第一篇：本科畢業(yè)論文--外文資料與中文翻譯

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

附錄：

外文資料與中文翻譯

外文資料：

Mine safety Coal mining historically has been a hazardous occupation but, in recent years, tremendous progress has been made in reducing accidental coal mine deaths and injuries.the main aspect is as following： ⑴ Safety of mine ventilation ?

Purposes of Mine Ventilation ?

Properly engineered control of the mine atmosphere is required to: ?

provide fresh air(oxygen)for men to breathe ?

provide a source of oxygen for internal combustion engines in machinery ?

dilute atmospheric contaminants to acceptable levels ?

maintain temperature and humidity within acceptable limits ?

remove atmospheric contaminants from the mine.Mine ventilation is twofold in purpose: first, it maintains life, and secondly it carries off dangerous gases.The historic role of ventilation was to provide a flow of fresh air sufficient to replace the oxygen consumed by the miners working underground.Today's mine ventilation primarily deals with noxious gases(mainly generated by trackless equipment underground).Canaries are said to have been used to detect gas in coal mines in the early stages of coal mining.This sensitive bird would be taken into the workings and, if it perished, the colliers would immediately leave the mine.In the 1920s the hand-turned fans were replaced with air-powered small turbine fans.河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

Large fans of the suction type were placed on the surface and gradually increased in size.Air from surface compressors was piped into the mine to power machinery and to assist in ventilation.Unless the air is properly distributed to the face, the mine ventilation system is not performing its primary function

[1]

.While it has always been recognized that this last part of ventilation is the most import, it is also the most difficult to achieve.The primary means of producing and controlling the airflow are also illustrated on Figure 1.Main fans, either singly or in combination, handle all of the air that passes through the entire system.These are usually, but not necessarily, located on surface, either exhausting air through the system as shown on Figure 1 or, alternatively, connected to downcast shafts or main intakes and forcing air into and through the system.Because of the additional hazards of gases and dust that may both be explosive, legislation governing the ventilation of coal mines is stricter than for most other underground facilities.In many countries, the main ventilation fans for coal mines are required, by law, to be placed on surface and may also be subject to other restrictions such as being located out of line with the connected shaft or drift and equipped with “blow-out” panels to help protect the fan in case of a mine

Figure 1.Typical elements of a main ventilation system 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

explosion.Stoppings and Seals:In developing a mine, connections are necessarily made between intakes and returns.When these are no longer required for access or ventilation, they should be blocked by stoppings in order to prevent short-circuiting of the airflow.Stoppings can be constructed from masonry, concrete blocks or fireproofed timber blocks.Prefabricated steel stoppings may also be employed.Stoppings should be well keyed into the roof, floor and sides, particularly if the strata are weak or in coal mines liable to spontaneous combustion.Leakage can be reduced by coating the high pressure face of the stopping with a sealant material and particular attention paid to the perimeter.Here again, in weak or chemically active strata, such coatings may be extended to the rock surfaces for a few metres back from the stopping.In cases where the airways are liable to convergence, precautions should be taken to protect stoppings against premature failure or cracking.These measures can vary from “crush pads” located at the top of the stopping to sliding or deformable panels on prefabricated stoppings.In all cases, components of stoppings should be fireproof and should not produce toxic fumes when heated.As a short term measure, fire-resistant brattice curtains may be tacked to roof, sides and floor to provide temporary stoppings where pressure differentials are low such as in locations close to the working areas.Where abandoned areas of a mine are to be isolated from the current ventilation infrastructure, seals should be constructed at the entrances of the connecting airways.If required to be explosion-proof, these consist of two or more stoppings, 5 to 10 metres apart, with the intervening space occupied by

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

sand, stone dust, compacted non-flammable rock waste, cement-based fill or other manufactured material.Steel girders, laced between roof and floor add structural strength.Grouting the surrounding strata adds to the integrity of the seal in weak ground.In coal mines, mining law or prudent regard for safety may require seals to be explosion-proof.Doors and airlocks：Where access must remain available between an intake and a return airway, a stopping may be fitted with a ventilation door.In its simplest form, this is merely a wooden or steel door hinged such that it opens towards the higher air pressure.This self-closing feature is supplemented by angling the hinges so that the door lifts slightly when opened and closes under its own weight.It is also advisable to fit doors with latches to prevent their opening in cases of emergency when the direction of pressure differentials may be reversed.Contoured flexible strips attached along the bottom of the door assist in reducing leakage, particularly when the airway is fitted with rail track.Ventilation doors located between main intakes and returns are usually built as a set of two or more to form an airlock.This prevents short-circuiting when one door is opened for passage of vehicles or personnel.The distance between doors should be capable of accommodating the longest train of vehicles required to pass through the airlock.For higher pressure differentials, multiple doors also allow the pressure break to be shared between doors.Mechanized doors, opened by pneumatic or electrical means are particularly convenient for the passage of vehicular traffic or where the size of the door or air pressure would make manual operation difficult.Mechanically operated doors may, again, be side-hinged or take the form of rollup or concertina

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

devices.They may be activated manually by a pull-rope or automatic sensing of an approaching vehicle or person.Large doors may be fitted with smaller hinged openings for access by personnel.Man-doors exposed to the higher pressure differentials may be difficult to open manually.In such cases, a sliding panel may be fitted in order to reduce that pressure differential temporarily while the door is opened.Interlock devices can also be employed on an airlock to prevent all doors from being opened simultaneously.Cfd applied to ventilation sys tems：Due to recent advances in computer processing power CFD has been used to solve a wide range of large and complex flow problems across many branches of engineering(Moloney et.al.1997/98/99).The increase in processor speed has also enabled the development of improved post processing and graphical techniques with which to visualize the results produced by these models.Recent research work has employed CFD models, validated by scale and full-scale experiments, to represent the ventilation flows and pollutant dispersion patterns within underground mine networks.In particular, studies by Moloney(1997)demonstrated that validated CFD models were able to successfully replicate the ventilation flows and gaseous pollutant dispersion patterns observed within auxiliary ventilated rapid development drivages.CFD has proven a capable method by which to identify detailed characteristics of the flow within critical areas such as the cutting face.The results produced by the CFD models were able to demonstrate the relative efficiency of the different auxiliary ventilation configurations in the dilution, dispersion and transport of the methane and dust from the development face.Further recent studies by Moloney et.al.(1999)have demonstrated that such

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

validated CFD models may be used to simulate the airflow and pollutant dispersion data for a wide range of mining and ventilation configurations.Each simulation exercise produces large sets of velocity, pressure and pollutant concentration data.⑵ Fires Methods of Control Fires that occur in mine airways usually commence from a single point of ignition.The initial fire is often quite small and, indeed, most fires are extinguished rapidly by prompt local action.Speed is of the essence.An energetic ignition that remains undetected, even for only a few minutes, can develop into a conflagration that becomes difficult or impossible to deal with.Sealing off the district or mine may then become inevitable.The majority of fires can be extinguished quickly if prompt action is taken.This underlines the importance of fire detection systems, training, a well-designed firefighting system and the ready availability of fully operational firefighting equipment.Fire extinguishers of an appropriate type should be available on vehicles and on the upstream side of all zones of increased fire hazard.These include storage areas and fixed locations of equipment such as electrical or compressor stations and conveyor gearheads.Neither water nor foam should be used where electricity is involved until it is certain that the power has been switched off.Fire extinguishers that employ carbon dioxide or dry powders are suitable for electrical fires or those involving flammable liquids.Deluge and sprinkler systems can be very effective in areas of fixed equipment, stores and over conveyors.These should be activated by thermal sensors rather than smoke or gas detectors in order to ensure that they are

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

operated only when open combustion occurs in the near vicinity.Except where electricity or flammable liquids are involved, water is the most common medium of firefighting.When applied to a burning surface, water helps to remove two sides of the fire triangle.The latent heat of the water as it vapourises and the subsequent thermal capacity of the water vapour assist in removing heat from the burning material.Furthermore, the displacement of air by water vapour and the liquid coating on cooler surfaces help to isolate oxygen from the fire.⑶ Methods of Dust Control The three major control methods used to reduce airborne dust in tunnels and underground mines: ventilation, water, and dust collectors.Ventilation air reduces dust through both dilution and displacement.The dilution mechanism operates when workers are surrounded by a dust cloud and additional air serves to reduce the dust concentration by diluting the cloud.The displacement mechanism operates when workers are upwind of dust sources and the air velocity is high enough to reliably keep the dust downwind.① Dilution Ventilation.The basic principle behind dilution ventilation is to provide more air and dilute the dust.Most of the time the dust is reduced roughly in proportion to the increase in airflow, but not always.The cost of and technical barriers to increased airflow can be substantial, particularly where air already moves through ventilation ductwork or shafts at velocities of 3,000 ft/min or more.② Displacement Ventilation.The basic principle behind displacement ventilation is to use the airflow in a way that confines the dust source and

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

keeps it away from workers by putting dust downwind of the workers.Every tunnel or mine passage with an airflow direction that puts dust downwind of workers uses displacement ventilation.In mines, continuous miner faces or tunnel boring machines on exhaust ventilation use displacement ventilation.Enclosure of a dust source, such as a conveyor belt transfer point, along with extraction of dusty air from the enclosure, is another example of displacement ventilation.Displacement ventilation can be hard to implement.However, if done well, it is the most effective dust control technique available, and it is worth considerable effort to get it right.The difficulty is that when workers are near a dust source, say, 10 to 20 ft from the source, keeping them upwind requires a substantial air velocity, typically between 60 and 150 ft/min.There is not always enough air available to achieve these velocities.③ Water sprays.The role of water sprays in mining is a dual one: wetting of the broken material being transported and,airborne capture.Of the two, wetting of the broken material is far more effective.Adequate wetting is extremely important for dust control.The vast majority of dust particles created during breakage are not released into the air, but stay attached to the surface of the broken material.Wetting this broken material ensures that the dust particles stay attached.As a result, adding more water can usually(but not always)be counted on to reduce dust.For example, coal mine operators have been able to reduce the dust from higher longwall production levels by raising the shearer water flow rate to an average of 100gpm.Compared to the amount of coal mined, on a weight basis, this 100gpm is equivalent to 1.9% added moisture from the shearer alone.河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

Unfortunately, excessive moisture levels can also result in a host of materials handling problems, operational headaches, and product quality issues, so an upper limit on water use is sometimes reached rather quickly.As a result, an alternative to simply adding more water is to ensure that the broken material is being wetted uniformly.⑷ Mine Drainage Water invades almost every mine in the form of ：direct precipitation(rain and snow), surface runoff, underground percolation.Flows of water have an important effect on the cost and progress of many mining operations and present life and property hazards in some cases.Means of Mine-water Control（Mine Drainage）: As shafts and other mine openings extend below the water table, water is likely to be encountered and to seep into the openings to an extent depending upon the area of rock surface exposed, the hydrostatic pressure, and other factors.In order to continue mining operations, it is therefore necessary to lower the ground water level in the vicinity of the mine by artificial means to keep the workings free of water as well as preventing the flow of surface water into the(surface or underground)mine.This operation is known as mine drainage.Means of mine drainage are limited by circumstances and objectives.The following types of mine-water control can be used singly or more effectively in combination: ① Locate shafts or excavations in best ground and protect from direct water inflow from surfaces.② Divert or drain water at or near surface.河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

③ Reduce permeability of rock mass by grouting with special types of cement, bentonite and liquid chemical grouts(water sealing).④ Case or cement exploration drill holes.⑤ Drill pilot holes in advance of work wherever there may be sudden influents at rates potentially inconvenient.⑥ Dewater bedrock at depth by pumping through dewatering wells or from an accessible place in the mine.。

5.Hearing Loss among Miners and Measures to Protect Hearing

Everyone knows that mining is a noisy job, but did you know that you are nine times more likely to lose your hearing than someone who works in a quieter job? If unprotected from noise on the job, by age 50, you will probably need hearing aids.Obviously, the best solution is to engineer out the noise, but that isn’t always immediately possible.Until mines are quieter, one way you can help save your vital sense of hearing is to use hearing protectors whenever the noise around you is hazardous.Even if you already have some hearing loss, you can use hearing protectors to prevent your hearing from getting worse.When loud noise is present, proper use of hearing protectors will help miners pre-vent most or all noise-induced hearing loss.Both employers and miners, working together, can take steps to reduce the risk of permanent hearing loss.Engineering controls should be the number one priority in the battle to eliminate hazardous noise.When replacing or upgrading equipment, mine owners and operators should “buy quiet” whenever possible.In many situations, sound barriers, sound dampening material, enclosed cabs, or other noise controls can reduce miner’s exposure to noise.But, if engineering controls have not eliminated

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

the noise hazard, then employers should provide hearing protectors that meet the special needs of miners for: comfort, convenience, and usability in a mining environment.Employers should provide training to miners on how to select and wear a variety of hearing protectors, and miners should make a conscientious effort to use the devices effectively.Miners need to know that hearing protectors can safely be worn in a mine along with other safety equipment.In fact, sometimes hearing protectors can actually help miners hear warning signals, alarms, and speech by muffling the level of continuous background noise.Miners should also be assured that properly worn earplugs will not damage their ear canals or eardrums.If the job requires miners to talk with one another, hearing protectors with built-in communication circuits are available.New protectors with active circuits that muffle background noise while amplifying nearby speech are available.These may be especially useful in a mining environment where the noise is intermittent.Some of these electronic devices may not yet be approved for underground mining, but are already in use for above ground mining and heavy construction.If we do these, mining will be become more secure.河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

中文翻譯：

煤礦安全

在歷史上，煤礦開采一直是危險(xiǎn)的行業(yè)。但是，在近幾年中，人們?cè)跍p少煤礦傷亡事故方面取得了巨大的進(jìn)步。主要有以下幾個(gè)方面： ⑴ 礦井通風(fēng)安全

礦山通風(fēng)的目標(biāo)：

? 從工程技術(shù)來講，正確控制礦山空氣需要：

? 提供新鮮的空氣（氧氣）工，供人呼吸； ? 提供氧氣來源，供給各種機(jī)械上的內(nèi)燃機(jī)； ? 稀釋空氣中的污染物，以達(dá)到允許標(biāo)準(zhǔn)； ? 保持空氣的溫度和濕度在容許的界限內(nèi)； ? 除去空氣當(dāng)中來自礦山的污染物。

礦山通風(fēng)的目標(biāo)有兩部分內(nèi)容：首先，維持生命；其次，帶走有毒的氣體。礦山通風(fēng)在歷史上重要的角色是提供足量的新鮮空氣，以代替井下工作的礦工所消耗的氧氣?，F(xiàn)今，礦山通風(fēng)主要對(duì)付有害的氣體（主要由無軌設(shè)備產(chǎn)生）。

在煤礦開采的早期，人們已用金絲雀來檢測(cè)瓦斯。這種敏感的鳥帶到工作地點(diǎn)，如果發(fā)現(xiàn)它死亡了，礦工將立即離開礦井。20世紀(jì)20年代，手工轉(zhuǎn)動(dòng)的風(fēng)機(jī)被小型的空氣動(dòng)力渦輪風(fēng)機(jī)所取代。大型的抽出式風(fēng)機(jī)安置在地表，并且其尺寸在逐漸增加。地面的壓縮機(jī)把風(fēng)流通過管道壓入礦井中，供給動(dòng)力機(jī)械和輔助通風(fēng)。

除非給工作面分配了合適的風(fēng)量，否則礦井通風(fēng)系統(tǒng)就沒有完成它的主要任務(wù)。雖然人們普遍認(rèn)識(shí)到通風(fēng)的這個(gè)最終任務(wù)是極其重要的，河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

但是要完成這個(gè)任務(wù)也是極其困難的。

圖1也表示出了產(chǎn)生和控制風(fēng)流的主要方法。主要通風(fēng)機(jī)，單獨(dú)或聯(lián)合運(yùn)行，控制流經(jīng)整個(gè)系統(tǒng)的所有風(fēng)流。主要通風(fēng)機(jī)通常（但不是必須的）安置在地面，或者如圖1所示的那樣抽出風(fēng)流流過系統(tǒng)，或者與進(jìn)風(fēng)豎井或主要進(jìn)風(fēng)道相連，壓入風(fēng)流進(jìn)入和流經(jīng)系統(tǒng)。由于煤礦瓦斯和粉塵都可能爆炸，這是其他地下設(shè)施所不具有的危害，所以煤礦的保障通風(fēng)的法規(guī)比其他地下設(shè)施要嚴(yán)格。許多國(guó)家的法規(guī)

Figure 1.Typical elements of a main

ventilation system 規(guī)定，煤礦中的主要通風(fēng)機(jī)必須安置在地面，并且還有其他一些限制，例如不安裝在和豎井或巷道呈直線的位置，配備沖擊板（防爆門）以在煤礦發(fā)生爆炸時(shí)，起到保護(hù)風(fēng)機(jī)的作用。

風(fēng)墻和密閉：礦山在開采過程中，進(jìn)風(fēng)和回風(fēng)之間需要一些連接設(shè)施。當(dāng)巷道不再需要通過或通風(fēng)，那么應(yīng)用風(fēng)墻封閉，以防止風(fēng)流短路。構(gòu)筑風(fēng)墻的材料為磚石、混凝土或耐火木材。另外，也使用預(yù)先制成的鋼制風(fēng)墻。風(fēng)墻應(yīng)充分楔入頂板、地板和四周，尤其當(dāng)巖層松軟或者煤礦易發(fā)生自燃的情況下。在風(fēng)墻壓力高的一面涂上一層密封劑，并特別注意其周界，那么漏風(fēng)會(huì)減少。這里同樣，在松軟和化學(xué)活性強(qiáng)的巖層中，這種涂層應(yīng)延伸到巖層表面距風(fēng)墻后面幾米處。在風(fēng)路易于集中的情況下，應(yīng)采取預(yù)防措施來保護(hù)風(fēng)墻，以避免過早出現(xiàn)故障或者破裂。這些措施從在風(fēng)墻的頂部安置壓墊到在預(yù)制風(fēng)墻上安置滑動(dòng)的或可變形

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文 的面板。在所有情況下，風(fēng)墻的組成成分是防火的，當(dāng)加熱時(shí)不應(yīng)產(chǎn)生有毒煙氣。

作為一種短期措施，風(fēng)障簾被固定在頂板、四周和底板，形成一種臨時(shí)密閉，這用于壓差小的地方，例如開采區(qū)域的附近位置。

當(dāng)?shù)V井報(bào)廢區(qū)域需要同現(xiàn)有基本通風(fēng)結(jié)構(gòu)隔離，應(yīng)在連接風(fēng)道的入口處構(gòu)造密閉。如果要求密閉具有防爆性，它們應(yīng)由兩個(gè)或多個(gè)間距為5~10米的風(fēng)墻組成，在風(fēng)墻之間的區(qū)域填充沙、石粉、緊密的不燃巖石廢料、以水泥為基礎(chǔ)的填充物或其他人造材料。鋼梁架在頂板和底板之間，以增加結(jié)構(gòu)強(qiáng)度。用薄灰漿填塞巖層周圍，增加了松軟地面上密閉的完整性。煤礦中，礦業(yè)法規(guī)或謹(jǐn)慎的安全考慮可能要求密閉為防爆的。

風(fēng)門和風(fēng)閘：當(dāng)進(jìn)風(fēng)和回風(fēng)之間必須通行時(shí)，在風(fēng)墻上應(yīng)安裝一個(gè)通風(fēng)門。最簡(jiǎn)單的形式是裝有鉸鏈的木制或鋼制風(fēng)門，能夠在風(fēng)流壓力大的一側(cè)開啟。使鉸鏈形成角度補(bǔ)充了這種半關(guān)閉特性，從而使風(fēng)門打開時(shí)有輕微地提升，在自身的重力下關(guān)閉。建議在風(fēng)門上安裝插銷，以防止在壓差方向反向的緊急情況下，風(fēng)門被打開。沿著風(fēng)門的底部縛上具有特定斷面形狀的柔韌性條帶，有助于減少漏風(fēng)，尤其當(dāng)風(fēng)路上鋪有軌道時(shí)。

安設(shè)在主要進(jìn)風(fēng)和回風(fēng)之間的通風(fēng)門通常構(gòu)建為兩道或多道，形成了風(fēng)閘。這防止了當(dāng)一道風(fēng)門打開讓車輛和人員通行時(shí)風(fēng)流短路。風(fēng)門之間的距離應(yīng)能夠容納需通過風(fēng)閘的交通工具中的最長(zhǎng)列車。壓差高時(shí)，多層風(fēng)門也使壓力突變均分到各風(fēng)門上。

機(jī)械風(fēng)門由氣動(dòng)力或電力開啟，這對(duì)于車輛通行尤其方便，對(duì)于由于風(fēng)門尺寸小或空氣壓力造成手動(dòng)操作困難的情況下很便利的。機(jī)械操作風(fēng)門也可以是一側(cè)裝鉸鏈的形式，還可以呈手工卷制的雪茄煙或六角手風(fēng)琴形式。它們可以通過拖繩人工操作，也可以自動(dòng)感覺接近的車輛

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

或人員。大型風(fēng)門安裝有帶鉸鏈的小門供人員通行。暴露在較高壓差下的人門人工開啟可能困難。這種情況下，安裝一滑動(dòng)面板，當(dāng)風(fēng)門打開時(shí)能暫時(shí)減小壓差。在風(fēng)閘上也應(yīng)采用互鎖裝置，以阻止所有風(fēng)門同時(shí)被打開。

CFD在通風(fēng)中的應(yīng)用：由于計(jì)算機(jī)處理能力得到了新發(fā)展，所以CFD已經(jīng)被用來解決許多工程學(xué)科中大量的規(guī)模巨大、結(jié)構(gòu)復(fù)雜的流體問題。處理器速度的提高也促使了改良的后處理方法和圖解法的發(fā)展，可以將這些模型產(chǎn)生的結(jié)果可視化。近來的研究工作已經(jīng)采用CFD模型來描繪在地下礦井網(wǎng)絡(luò)中風(fēng)流流動(dòng)和污染物的分布形式，并通過比例或全尺度的實(shí)驗(yàn)驗(yàn)證了其有效性。尤其是Moloney在1997年所作的研究表明：已經(jīng)驗(yàn)證其有效性的CFD模型能夠成功地重現(xiàn)局部通風(fēng)快速掘進(jìn)中所觀測(cè)到的風(fēng)流流動(dòng)和污染物的分布形式。已證實(shí)CFD是一種有效的方法，可用來確定臨界面積區(qū)（如工作面）流體的詳細(xì)特征。這種模型所產(chǎn)生的結(jié)果也能表明不同的局部通風(fēng)結(jié)構(gòu)中，掘進(jìn)工作面產(chǎn)生的瓦斯和粉塵運(yùn)送、彌散和稀釋的相對(duì)效率。1999 年，Moloney等近一步的新研究表明：已經(jīng)驗(yàn)證的CFD模型可以用來模擬許多不同采礦和通風(fēng)結(jié)構(gòu)中的氣流和污染物的散布數(shù)據(jù)，每次模擬訓(xùn)練都會(huì)產(chǎn)生大量的速度、壓力和污染物濃度的數(shù)據(jù)。⑵ 火災(zāi)的控制方法

發(fā)生在礦井風(fēng)巷中的火災(zāi)通常開始于一點(diǎn)的燃燒。最初火勢(shì)非常小，實(shí)際上只要能夠及時(shí)地進(jìn)行局部處理，大多數(shù)火災(zāi)都能被立即撲滅?？焖俚男袆?dòng)是非常重要的。旺盛的燃燒如果未被發(fā)現(xiàn)，那么即使只有幾分鐘，也能夠發(fā)展為大火，從而很難或者不可能撲滅了。因而，封閉區(qū)域或者整個(gè)礦井可能變得不可避免了。

如果及時(shí)行動(dòng)，大部分火災(zāi)都能夠撲滅?；馂?zāi)探測(cè)系統(tǒng)、培訓(xùn)、設(shè)

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

計(jì)良好的滅火系統(tǒng)和現(xiàn)成的能充分運(yùn)行的滅火設(shè)備很重要。合適型號(hào)的滅火器應(yīng)安置在車輛上面和火災(zāi)危險(xiǎn)大的所有區(qū)域的逆流側(cè)。這包括儲(chǔ)藏室區(qū)域和設(shè)備的固定安裝位置（例如電站或壓縮機(jī)站和運(yùn)輸機(jī)的傳送機(jī)頭）。

電力火災(zāi)既不能用水也不能用泡沫滅火，除非確定電源已關(guān)。使用二氧化碳或干粉的滅火器適于撲滅電力火災(zāi)或易燃液體火災(zāi)。

洪水和自動(dòng)噴水系統(tǒng)在固定設(shè)備、儲(chǔ)藏室和輸送機(jī)上面這些地區(qū)很有效。這些裝置要激活應(yīng)通過熱力探測(cè)器而不是煙霧或瓦斯探測(cè)器，以確保只有當(dāng)在鄰近地區(qū)發(fā)生明火燃燒時(shí)才自動(dòng)運(yùn)轉(zhuǎn)。

除了電力和可燃液體火災(zāi)外，水是滅火最常用的方法。當(dāng)水應(yīng)用在燃燒著表面時(shí)，它有助于消除火災(zāi)三角形的兩個(gè)方面。水蒸發(fā)時(shí)具有的潛在熱能和隨后水蒸氣的熱力能幫助消除燃燒物質(zhì)的熱能。此外，水蒸氣取代空氣并且液體在較涼的表面形成覆蓋層，這有助于隔絕氧氣。3.粉塵控制方法

減少隧道內(nèi)和地下礦山中的懸浮粉塵，有三種主要控制方法：通風(fēng)、水和粉塵捕獲器。

通風(fēng)氣流通過稀釋和置換作用減少粉塵。當(dāng)工人處于粉塵云的包圍中，稀釋過程起作用，附加的氣流通過稀釋塵云，減少粉塵的濃度。當(dāng)工人逆著塵源的方向時(shí)，置換作用起作用，氣流速度足夠高以至于可靠地使粉塵保持順風(fēng)方向。

① 稀釋通風(fēng)

稀釋通風(fēng)的基本原理是提供更多的空氣和稀釋粉塵。大多數(shù)情況下，減少的粉塵與增加的風(fēng)量大致成比例，但并不總是這樣。增加風(fēng)量的費(fèi)用和技術(shù)障礙是實(shí)際存在的，尤其是流過通風(fēng)管道或井筒的氣流速度已達(dá)到3000英尺/f分或更大。

② 置換通風(fēng)

置換通風(fēng)的基本原理是利用風(fēng)流約束塵源，使粉塵沿

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

著工人下風(fēng)向，從而遠(yuǎn)離工人。任一隧道或礦山通道中，如風(fēng)流方向使粉塵沿著工人下風(fēng)向運(yùn)動(dòng)，使用的都是置換通風(fēng)。在礦山中，回風(fēng)系統(tǒng)中連續(xù)采煤機(jī)的表面或隧道鉆探機(jī)，使用的是置換通風(fēng)。塵源的周圍，例如運(yùn)輸皮帶傳送處連同周圍為多塵空氣的采區(qū)，是置換通風(fēng)的又一個(gè)例子。置換通風(fēng)很難實(shí)現(xiàn)。然而，如果做得好，置換通風(fēng)是能利用的最有效的粉塵控制方法，值得付出大量的努力，使其運(yùn)行良好。困難之處在于：當(dāng)工人在塵源附近時(shí)，比方說10~20英尺，使工人逆著風(fēng)流需要相當(dāng)大的風(fēng)速，典型的是在60到150英尺/分之間。并不總是有足夠多的風(fēng)量能達(dá)到這么大的風(fēng)速。

③ 灑水

開采中灑水的作用是雙重的：濕潤(rùn)正被運(yùn)輸?shù)姆鬯槲镔|(zhì)、空中捕獲。這兩個(gè)作用中，濕潤(rùn)粉碎物質(zhì)非常有效。

適度的濕潤(rùn)對(duì)于粉塵控制來說是非常重要的。在粉碎過程中產(chǎn)生的粉塵顆粒大部分沒有釋放到空氣中，而是附著在粉碎物質(zhì)的表面。濕潤(rùn)破碎的物質(zhì)能夠確保粉塵顆粒保持附著狀態(tài)。因此，通常認(rèn)為加的水越多（但并不總是）也能減少粉塵。例如，煤礦操作員已能夠通過提高（滾筒式）采煤機(jī)的水流速度，來減少長(zhǎng)壁開采較高水平的粉塵，以至達(dá)到100(每分鐘加侖數(shù))。與開采煤的數(shù)量相比，以重量為基礎(chǔ)，采煤機(jī)單獨(dú)加的濕度100加侖（分）等于1.9%。可惜的是，過高的濕度也能導(dǎo)致許多材料的輸送問題，難于操作的問題，產(chǎn)品的質(zhì)量問題，所以，用水的上限有時(shí)能很快的達(dá)到。因此，用以替代僅僅增加水量的另外一種方法是確保粉碎的物質(zhì)能夠得到均勻的加濕。⑷ 礦山排水

幾乎每一個(gè)礦都會(huì)有水侵入，侵入形式為：直接降水（雨和雪）；地面逕流（地面流走的水就叫逕流）；地下滲透。涌水對(duì)許多開采作業(yè)的費(fèi)用和進(jìn)展會(huì)產(chǎn)生重要的影響，并且在某些情況下能夠造成人員傷亡和財(cái)

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

產(chǎn)損失。

控制礦山水的方法（礦山排水）：

當(dāng)井筒或其他礦山巷道延伸到潛水位以下時(shí)，很可能遇到水，水滲露到巷道的程度取決于暴露巖層表面的區(qū)域、流體靜壓力和其他因素。為了能夠繼續(xù)開采作業(yè)，因此需要通過人工方法降低礦山鄰近地區(qū)的地層水位，保持巷道內(nèi)無水，同時(shí)防止地表水流入到（地表或地下）礦山內(nèi)。這種操作稱為礦山排水。

礦山排水的方法受限于環(huán)境條件和客觀因素。下面控制礦山水的種類可以單獨(dú)使用，也可以更有效地聯(lián)合使用。

① 使井筒或巷道建在最佳的地面上，以防止直接水從地表流入。② 在地表或接近地表處，改變水的流向或者排水。

③ 用特殊類型的水泥、斑脫土（火山灰分解成的一種粘土)和液體化學(xué)漿（水填充物）進(jìn)行注漿，以降低巖石塊的滲透性。

④ 為探測(cè)鉆孔下套管或用水泥涂探測(cè)鉆孔。

⑤ 只要可能有突水，其速率可能不方便接近的地方，開采前打引水孔。

⑥ 通過疏水井和礦井內(nèi)可利用的地方抽水，以降低巖床水位。⑸ 礦工聽力損失和保護(hù)聽力的方法

每個(gè)人都知道采礦業(yè)是一個(gè)嘈雜的行業(yè)，但你聽力損失的可能性是從事安靜工作人員的九倍還多，這個(gè)你知道嗎？如果在工作中不保護(hù)自己遭受噪音的危害，那么到50歲時(shí)，你將可能需要助聽器。很顯然，最好的辦法是從技術(shù)上消除噪聲，但是通常這并不能馬上實(shí)現(xiàn)（很難實(shí)現(xiàn)）。除非礦山是較安靜的，否則只要你周圍的噪音具有危害性，幫助你保護(hù)及其重要的聽覺的一個(gè)方法是使用聽力防護(hù)罩。即使你已損失了部分聽力，你也應(yīng)使用聽力防護(hù)罩，以阻止聽力的進(jìn)一步惡化。當(dāng)巨大的噪聲

河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文

存在時(shí)，正確使用聽力防護(hù)罩將有助于礦工預(yù)防大多數(shù)甚至全部導(dǎo)致聽力損失的噪聲。

礦主和礦工應(yīng)一起采取措施，以降低聽力永久損失的危險(xiǎn)性。在消除噪音危害的戰(zhàn)役中，技術(shù)控制的方法是第一位的.當(dāng)?shù)V主和操作員更換或升級(jí)設(shè)備時(shí)，只要可能，應(yīng)當(dāng)購(gòu)買無噪音的設(shè)備。許多情況下，聲障、隔音材料、封閉的駕駛室或其他噪音控制方法能夠降低礦工的噪聲接觸。但是，如果技術(shù)控制方法不能消除噪聲危害，那么礦主應(yīng)當(dāng)提供聽力防護(hù)罩。防護(hù)罩應(yīng)滿足礦工的特殊需要：舒適、方便、在采礦環(huán)境下可用。礦主應(yīng)該培訓(xùn)礦工如何選擇和佩帶各種各樣的聽力防護(hù)罩，礦工應(yīng)當(dāng)盡心盡責(zé)地有效使用這些防護(hù)設(shè)備。

礦工應(yīng)該明白：礦山中，他們可以連同其他安全裝備來安全地佩帶聽力防護(hù)罩和。事實(shí)上，有時(shí)聽力防護(hù)罩使持續(xù)的背景噪音減弱，能夠幫助礦工聽到警告信號(hào)、發(fā)警報(bào)、說話。礦工也應(yīng)確信：正確的佩帶耳塞不會(huì)損害他們的耳膜。如果礦工工作中需要相互通話時(shí)，可使用內(nèi)置通信電路的聽力防護(hù)罩。當(dāng)?shù)V山環(huán)境的噪音斷斷續(xù)續(xù)時(shí)，這些裝置尤為有用。出現(xiàn)一種帶有有源電路的防護(hù)罩，能夠減弱背景噪音，而放大附近的語音。這些電子裝置，有些還沒有在地下采礦中得到試驗(yàn)證明，但它們已經(jīng)在地面開采和大規(guī)模的建筑行業(yè)得到應(yīng)用。

如果做到這些方面，那么我們的采礦工作將變得更加安全。

第二篇：畢業(yè)論文外文翻譯

齒輪和軸的介紹

摘 要:在傳統(tǒng)機(jī)械和現(xiàn)代機(jī)械中齒輪和軸的重要地位是不可動(dòng)搖的。齒輪和軸主要 安裝在主軸箱來傳遞力的方向。通過加工制造它們可以分為許多的型號(hào)，分別用于許 多的場(chǎng)合。所以我們對(duì)齒輪和軸的了解和認(rèn)識(shí)必須是多層次多方位的。關(guān)鍵詞:齒輪；軸 關(guān)鍵詞 在直齒圓柱齒輪的受力分析中，是假定各力作用在單一平面的。我們將研究作用 力具有三維坐標(biāo)的齒輪。因此，在斜齒輪的情況下，其齒向是不平行于回轉(zhuǎn)軸線的。而在錐齒輪的情況中各回轉(zhuǎn)軸線互相不平行。像我們要討論的那樣，尚有其他道理需 要學(xué)習(xí)，掌握。斜齒輪用于傳遞平行軸之間的運(yùn)動(dòng)。傾斜角度每個(gè)齒輪都一樣，但一個(gè)必須右旋 斜齒，而另一個(gè)必須是左旋斜齒。齒的形狀是一濺開線螺旋面。如果一張被剪成平行 四邊形（矩形）的紙張包圍在齒輪圓柱體上，紙上印出齒的角刃邊就變成斜線。如果 我展開這張紙，在血角刃邊上的每一個(gè)點(diǎn)就發(fā)生一漸開線曲線。直齒圓柱齒輪輪齒的初始接觸處是跨過整個(gè)齒面而伸展開來的線。斜齒輪輪齒的 初始接觸是一點(diǎn)，當(dāng)齒進(jìn)入更多的嚙合時(shí)，它就變成線。在直齒圓柱齒輪中，接觸是平行于回轉(zhuǎn)軸線的。在斜齒輪中，該先是跨過齒面的對(duì)角線。它是齒輪逐漸進(jìn)行嚙合 并平穩(wěn)的從一個(gè)齒到另一個(gè)齒傳遞運(yùn)動(dòng)，那樣就使斜齒輪具有高速重載下平穩(wěn)傳遞運(yùn) 動(dòng)的能力。斜齒輪使軸的軸承承受徑向和軸向力。當(dāng)軸向推力變的大了或由于別的原 因而產(chǎn)生某些影響時(shí)，那就可以使用人字齒輪。雙斜齒輪（人字齒輪）是與反向的并 排地裝在同一軸上的兩個(gè)斜齒輪等效。他們產(chǎn)生相反的軸向推力作用，這樣就消除了 軸向推力。當(dāng)兩個(gè)或更多個(gè)單向齒斜齒輪被在同一軸上時(shí)，齒輪的齒向應(yīng)作選擇，以 便產(chǎn)生最小的軸向推力。交錯(cuò)軸斜齒輪或螺旋齒輪，他們是軸中心線既不相交也不平行。交錯(cuò)軸斜齒輪的 齒彼此之間發(fā)生點(diǎn)接觸，它隨著齒輪的磨合而變成線接觸。因此他們只能傳遞小的載 荷和主要用于儀器設(shè)備中，而且肯定不能推薦在動(dòng)力傳動(dòng)中使用。交錯(cuò)軸斜齒輪與斜 齒輪之間在被安裝后互相捏合之前是沒有任何區(qū)別的。它們是以同樣的方法進(jìn)行制 造。一對(duì)相嚙合的交錯(cuò)軸斜齒輪通常具有同樣的齒向，即左旋主動(dòng)齒輪跟右旋從動(dòng)齒 輪相嚙合。在交錯(cuò)軸斜齒設(shè)計(jì)中，當(dāng)該齒的斜角相等時(shí)所產(chǎn)生滑移速度最小。然而當(dāng)

該齒的斜角不相等時(shí)，如果兩個(gè)齒輪具有相同齒向的話，大斜角齒輪應(yīng)用作主動(dòng)齒輪。蝸輪與交錯(cuò)軸斜齒輪相似。小齒輪即蝸桿具有較小的齒數(shù)，通常是一到四齒，由 于它們完全纏繞在節(jié)圓柱上，因此它們被稱為螺紋齒。與其相配的齒輪叫做蝸輪，蝸 輪不是真正的斜齒輪。蝸桿和蝸輪通常是用于向垂直相交軸之間的傳動(dòng)提供大的角速 度減速比。蝸輪不是斜齒輪，因?yàn)槠潺X頂面做成中凹形狀以適配蝸桿曲率，目的是要 形成線接觸而不是點(diǎn)接觸。然而蝸桿蝸輪傳動(dòng)機(jī)構(gòu)中存在齒間有較大滑移速度的缺 點(diǎn)，正像交錯(cuò)軸斜齒輪那樣。蝸桿蝸輪機(jī)構(gòu)有單包圍和雙包圍機(jī)構(gòu)。單包圍機(jī)構(gòu)就是蝸輪包裹著蝸桿的一種機(jī) 構(gòu)。當(dāng)然，如果每個(gè)構(gòu)件各自局部地包圍著對(duì)方的蝸輪機(jī)構(gòu)就是雙包圍蝸輪蝸桿機(jī)構(gòu)。著兩者之間的重要區(qū)別是，在雙包圍蝸輪組的輪齒間有面接觸，而在單包圍的蝸輪組 的輪齒間有線接觸。一個(gè)裝置中的蝸桿和蝸輪正像交錯(cuò)軸斜齒輪那樣具有相同的齒 向，但是其斜齒齒角的角度是極不相同的。蝸桿上的齒斜角度通常很大，而蝸輪上的 則極小，因此習(xí)慣常規(guī)定蝸桿的導(dǎo)角，那就是蝸桿齒斜角的余角；也規(guī)定了蝸輪上的 齒斜角，該兩角之和就等于 90 度的軸線交角。當(dāng)齒輪要用來傳遞相交軸之間的運(yùn)動(dòng)時(shí)，就需要某種形式的錐齒輪。雖然錐齒輪 通常制造成能構(gòu)成 90 度軸交角，但它們也可產(chǎn)生任何角度的軸交角。輪齒可以鑄出，銑制或滾切加工。僅就滾齒而言就可達(dá)一級(jí)精度。在典型的錐齒輪安裝中，其中一個(gè) 錐齒輪常常裝于支承的外側(cè)。這意味著軸的撓曲情況更加明顯而使在輪齒接觸上具有 更大的影響。另外一個(gè)難題，發(fā)生在難于預(yù)示錐齒輪輪齒上的應(yīng)力，實(shí)際上是由于齒輪被加工 成錐狀造成的。直齒錐齒輪易于設(shè)計(jì)且制造簡(jiǎn)單，如果他們安裝的精密而確定，在運(yùn)轉(zhuǎn)中會(huì)產(chǎn)生 良好效果。然而在直齒圓柱齒輪情況下，在節(jié)線速度較高時(shí)，他們將發(fā)出噪音。在這 些

情況下，螺旋錐齒輪比直齒輪能產(chǎn)生平穩(wěn)的多的嚙合作用，因此碰到高速運(yùn)轉(zhuǎn)的場(chǎng) 合那是很有用的。當(dāng)在汽車的各種不同用途中，有一個(gè)帶偏心軸的類似錐齒輪的機(jī)構(gòu)，那是常常所希望的。這樣的齒輪機(jī)構(gòu)叫做準(zhǔn)雙曲面齒輪機(jī)構(gòu)，因?yàn)樗鼈兊墓?jié)面是雙曲 回轉(zhuǎn)面。這種齒輪之間的輪齒作用是沿著一根直線上產(chǎn)生滾動(dòng)與滑動(dòng)相結(jié)合的運(yùn)動(dòng)并 和蝸輪蝸桿的輪齒作用有著更多的共同之處。軸是一種轉(zhuǎn)動(dòng)或靜止的桿件。通常有圓形橫截面。在軸上安裝像齒輪，皮帶輪，飛輪，曲柄，鏈輪和其他動(dòng)力傳遞零件。軸能夠承受彎曲，拉伸，壓縮或扭轉(zhuǎn)載荷，這些力相結(jié)合時(shí)，人們期望找到靜強(qiáng)度和疲勞強(qiáng)度作為設(shè)計(jì)的重要依據(jù)。因?yàn)閱胃S 可以承受靜壓力，變應(yīng)力和交變應(yīng)力，所有的應(yīng)力作用都是同時(shí)發(fā)生的。“軸”這個(gè)詞包含著多種含義，例如心軸和主軸。心軸也是軸，既可以旋轉(zhuǎn)也可 以靜止的軸，但不承受扭轉(zhuǎn)載荷。短的轉(zhuǎn)動(dòng)軸常常被稱為主軸。當(dāng)軸的彎曲或扭轉(zhuǎn)變形必需被限制于很小的范圍內(nèi)時(shí)，其尺寸應(yīng)根據(jù)變形來確 定，然后進(jìn)行應(yīng)力分析。因此，如若軸要做得有足夠的剛度以致?lián)锨惶螅敲春?應(yīng)力符合安全要求那是完全可能的。但決不意味著設(shè)計(jì)者要保證；它們是安全的，軸 幾乎總是要進(jìn)行計(jì)算的，知道它們是處在可以接受的允許的極限以內(nèi)。因之，設(shè)計(jì)者 無論何時(shí)，動(dòng)力傳遞零件，如齒輪或皮帶輪都應(yīng)該設(shè)置在靠近支持軸承附近。這就減 低了彎矩，因而減小變形和彎曲應(yīng)力。雖然來自 M.H.G 方法在設(shè)計(jì)軸中難于應(yīng)用，但它可能用來準(zhǔn)確預(yù)示實(shí)際失效。這 樣，它是一個(gè)檢驗(yàn)已經(jīng)設(shè)計(jì)好了的軸的或者發(fā)現(xiàn)具體軸在運(yùn)轉(zhuǎn)中發(fā)生損壞原因的好方 法。進(jìn)而有著大量的關(guān)于設(shè)計(jì)的問題，其中由于別的考慮例如剛度考慮，尺寸已得到 較好的限制。設(shè)計(jì)者去查找關(guān)于圓角尺寸、熱處理、表面光潔度和是否要進(jìn)行噴丸處理等資料，那真正的唯一的需要是實(shí)現(xiàn)所要求的壽命和可靠性。由于他們的功能相似，將離合器和制動(dòng)器一起處理。簡(jiǎn)化摩擦離合器或制動(dòng)器的 動(dòng)力學(xué)表達(dá)式中，各自以角速度 w1 和 w2 運(yùn)動(dòng)的兩個(gè)轉(zhuǎn)動(dòng)慣量 I1 和 I2，在制動(dòng)器情 況下其中之一可能是零，由于接上離合器或制動(dòng)器而最終要導(dǎo)致同樣的速度。因?yàn)閮?個(gè)構(gòu)件開始以不同速度運(yùn)轉(zhuǎn)而使打滑發(fā)生了，并且在作用過程中能量散失，結(jié)果導(dǎo)致 溫升。在分析這些裝置的性能時(shí)，我們應(yīng)注意到作用力，傳遞的扭矩，散失的能量和 溫升。所傳遞的扭矩關(guān)系到作用力，摩擦系數(shù)和離合器或制動(dòng)器的幾何狀況。這是一 個(gè)靜力學(xué)問題。這個(gè)問題將必須對(duì)每個(gè)幾何機(jī)構(gòu)形狀分別進(jìn)行研究。然而溫升與能量 損失有關(guān)，研究溫升可能與制動(dòng)器或離合器的類型無關(guān)。因?yàn)閹缀涡螤畹闹匾允巧?熱表面。各種各樣的離合器和制動(dòng)器可作如下分類： 1．輪緣式內(nèi)膨脹制凍塊； 2．輪緣式外接觸制動(dòng)塊； 3．條帶式； 4．盤型或軸向式； 5．圓錐型；

6．混合式。分析摩擦離合器和制動(dòng)器的各種形式都應(yīng)用一般的同樣的程序，下面的步驟是必 需的： 1．假定或確定摩擦表面上壓力分布； 2．找出最大壓力和任一點(diǎn)處壓力之間的關(guān)系； 3．應(yīng)用靜平衡條件去找尋（a）作用力；（b）扭矩；(c)支反力?；旌鲜诫x合器包括幾個(gè)類型，例如強(qiáng)制接觸離合器、超載釋放保護(hù)離合器、超越 離合器、磁液離合器等等。強(qiáng)制接觸離合器由一個(gè)變位桿和兩個(gè)夾爪組成。各種強(qiáng)制接觸離合器之間最大的 區(qū)別與夾爪的設(shè)計(jì)有關(guān)。為了在結(jié)合過程中給變換作用予較長(zhǎng)時(shí)間周期，夾爪可以是 棘輪式的，螺旋型或齒型的。有時(shí)使用許多齒或夾爪。他們可能在圓周面上加工齒，以便他們以圓柱周向配合來結(jié)合或者在配合元件的端面上加工齒來結(jié)合。雖然強(qiáng)制離合器不像摩擦接觸離合器用的那么廣泛，但它們確實(shí)有很重要的運(yùn) 用。離合器需要同步操作。有些裝置例如線性驅(qū)動(dòng)裝置或電機(jī)操作螺桿驅(qū)動(dòng)器必須運(yùn)行到一定的限度然后 停頓下來。為著這些用途就需要超載釋放保護(hù)離合器。這些離合器通常用彈簧加載，以使得在達(dá)到預(yù)定的力矩時(shí)釋放。當(dāng)?shù)竭_(dá)超載點(diǎn)時(shí)聽到的“喀嚓”聲就被認(rèn)定為是所 希望的信號(hào)聲。超越離合器

或連軸器允許機(jī)器的被動(dòng)構(gòu)件“空轉(zhuǎn)”或“超越”，因?yàn)橹鲃?dòng)驅(qū)動(dòng)件 停頓了或者因?yàn)榱硪粋€(gè)動(dòng)力源使被動(dòng)構(gòu)件增加了速度。這種離合器通常使用裝在外套 筒和內(nèi)軸件之間的滾子或滾珠。該內(nèi)軸件，在它的周邊加工了數(shù)個(gè)平面。驅(qū)動(dòng)作用是 靠在套筒和平面之間契入的滾子來獲得。因此該離合器與具有一定數(shù)量齒的棘輪棘爪 機(jī)構(gòu)等效。磁液離合器或制動(dòng)器相對(duì)來說是一個(gè)新的發(fā)展，它們具有兩平行的磁極板。這些 磁極板之間有磁粉混合物潤(rùn)滑。電磁線圈被裝入磁路中的某處。借助激勵(lì)該線圈，磁 液混合物的剪切強(qiáng)度可被精確的控制。這樣從充分滑移到完全鎖住的任何狀態(tài)都可以 獲得。

GEAR AND SHAFT INTRODUCTION

Abstract: The important position of the wheel gear and shaft can't falter in

traditional machine and modern machines.The wheel gear and shafts mainly install the direction that delivers the dint at the principal axis box.The passing to process to make them can is divided into many model numbers, useding for many situations respectively.So we must be the multilayers to the understanding of the wheel gear and shaft in many ways.Key words: Wheel gear;Shaft

In the force analysis of spur gears, the forces are assumed to act in a single plane.We shall study gears in which the forces have three dimensions.The reason for this, in the case of helical gears, is that the teeth are not parallel to the axis of rotation.And in the case of bevel gears, the rotational axes are not parallel to each other.There are also other reasons, as we shall learn.Helical gears are used to transmit motion between parallel shafts.The helix angle is the same on each gear, but one gear must have a right-hand helix and the other a left-hand helix.The shape of the tooth is an involute helicoid.If a piece of paper cut in the shape of a parallelogram is wrapped around a cylinder, the angular edge of the paper becomes a helix.If we unwind this paper, each point on the angular edge generates an involute curve.The surface obtained when every point on the edge generates an involute is called an involute helicoid.The initial contact of spur-gear teeth is a line extending all the way across the face of the tooth.The initial contact of helical gear teeth is a point, which changes into a line as the teeth come into more engagement.In spur gears the line of contact is parallel to the axis of the rotation;in helical gears, the line is diagonal across the face of the tooth.It is this gradual of the teeth and the smooth transfer of load from one tooth to another, which give helical gears the ability to transmit heavy loads at high

speeds.Helical gears subject the shaft bearings to both radial and thrust loads.When the thrust loads become high or are objectionable for other reasons, it may be desirable to use double helical gears.A double helical gear(herringbone)is equivalent to two helical gears of opposite hand, mounted side by side on the same shaft.They develop opposite thrust reactions and thus cancel out the thrust load.When two or more single helical gears are mounted on the same shaft, the hand of the gears should be selected so as to produce the minimum thrust load.Crossed-helical, or spiral, gears are those in which the shaft centerlines are neither parallel nor intersecting.The teeth of crossed-helical fears have point contact with each other, which changes to line contact as the gears wear in.For this reason they will carry out very small loads and are mainly for instrumental applications, and are definitely not recommended for use in the transmission of power.There is on difference between a crossed helical gear and a helical gear until they are mounted in mesh with each other.They are manufactured in the same way.A pair of meshed crossed helical gears usually have the same hand;that is ,a right-hand driver goes with a

right-hand driven.In the design of crossed-helical gears, the minimum sliding velocity is obtained when the helix angle are equal.However, when the helix angle are not equal, the gear with the larger helix angle should be used as the driver if both gears have the same hand.Worm gears are similar to crossed helical gears.The pinion or worm has a small number of teeth, usually one to four, and since they completely wrap around the pitch cylinder they are called threads.Its mating gear is called a worm gear, which is not a true helical gear.A worm and worm gear are used to provide a high angular-velocity reduction between nonintersecting shafts which are usually at right angle.The worm gear is not a helical gear because its face is made concave to fit the curvature of the worm in order to provide line contact instead of point contact.However, a disadvantage of worm gearing is the high sliding velocities across the teeth, the same as with crossed

helical gears.Worm gearing are either single or double enveloping.A single-enveloping gearing is one in which the gear wraps around or partially encloses the worm..A gearing in which each element partially encloses the other is, of course, a double-enveloping worm gearing.The important difference between the two is that area contact exists between the teeth of double-enveloping gears while only line contact between those of single-enveloping gears.The worm and worm gear of a set have the same hand of helix as for crossed helical gears, but the helix angles are usually quite different.The helix angle on the worm is generally quite large, and that on the gear very small.Because of this, it is usual to specify the lead angle on the worm, which is the complement of the worm helix angle, and the helix angle on the gear;the two angles are equal for a 90-deg.Shaft angle.When gears are to be used to transmit motion between intersecting shaft, some of bevel gear is required.Although bevel gear are usually made for a shaft angle of 90 deg.They may be produced for almost any shaft angle.The teeth may be cast, milled, or generated.Only the generated teeth may be classed as accurate.In a typical bevel gear mounting, one of the gear is often mounted outboard of the bearing.This means that shaft deflection can be more pronounced and have a greater effect on the contact of teeth.Another difficulty, which occurs in predicting the stress in bevel-gear teeth, is the fact the teeth are tapered.Straight bevel gears are easy to design and simple to manufacture and give very good results in service if they are mounted accurately and positively.As in the case of squr gears, however, they become noisy at higher values of the pitch-line velocity.In these cases it is often good design practice to go to the spiral bevel gear, which is the bevel counterpart of the helical gear.As in the case of helical gears, spiral bevel gears give a much smoother tooth action than straight bevel gears, and hence are useful where high speed are encountered.7

It is frequently desirable, as in the case of automotive differential applications, to have gearing similar to bevel gears but with the shaft offset.Such gears are called hypoid gears because their pitch surfaces are hyperboloids of revolution.The tooth action between such gears is a combination of rolling and sliding along a straight line and has much in common with that of worm gears.A shaft is a rotating or stationary member, usually of circular cross section, having mounted upon it such elementsas gears, pulleys, flywheels, cranks, sprockets, and other power-transmission elements.Shaft may be subjected to bending, tension, compression, or torsional loads, acting singly or in combination with one another.When they are combined, one may expect to find both static and fatigue strength to be important design considerations, since a

single shaft may be subjected to static stresses, completely reversed, and repeated stresses, all acting at the same time.The word “shaft” covers numerous variations, such as axles and spindles.Anaxle is a shaft, wither stationary or rotating, nor subjected to torsion load.A shirt rotating shaft is often called a spindle.When either the lateral or the torsional deflection of a shaft must be held to close limits, the shaft must be sized on the basis of deflection before analyzing the stresses.The reason for this is that, if the shaft is made stiff enough so that the deflection is not too large, it is probable that the resulting stresses will be safe.But by no means should the designer assume that they are safe;it is almost always necessary to calculate them so that he knows they are within acceptable limits.Whenever possible, the power-transmission elements, such as gears or pullets, should be located close to the supporting bearings, This reduces the bending moment, and hence the deflection and bending stress.Although the von Mises-Hencky-Goodman method is difficult to use in design of shaft, it probably comes closest to predicting actual failure.Thus it is a good way of checking a shaft that has already been designed or of discovering

why a particular shaft has failed in service.Furthermore, there are a considerable number of shaft-design problems in which the dimension are pretty well limited by other considerations, such as rigidity, and it is only necessary for the designer to discover something about the fillet sizes, heat-treatment, and surface finish and whether or not shot peening is necessary in order to achieve the required life and reliability.Because of the similarity of their functions, clutches and brakes are treated together.In a simplified dynamic representation of a friction clutch, or brake, two inertias I1 and I2 traveling at the respective angular velocities W1 and W2, one of which may be zero in the case of brake, are to be brought to the same speed by engaging the clutch or brake.Slippage occurs because the two elements are running at different speeds and energy is dissipated during actuation, resulting in a temperature rise.In analyzing the performance of these devices we shall be interested in the actuating force, the torque transmitted, the energy loss and the temperature rise.The torque transmitted is related to the actuating force, the coefficient of friction, and the geometry of the clutch or brake.This is problem in static, which will have to be studied separately for eath geometric configuration.However, temperature rise is related to energy loss and can be studied without regard to the type of brake or clutch because the geometry of interest is the heat-dissipating surfaces.The various types of clutches and brakes may be classified as fllows:

1.Rim type with internally expanding shoes 2.Rim type with externally contracting shoes 3.Band type 4.Disk or axial type 5.Cone type 6.Miscellaneous type The analysis of all type of friction clutches and brakes use the same general procedure.The following step are necessary:

1.Assume or determine the distribution of pressure on the frictional surfaces.2.Find a relation between the maximum pressure and the pressure at any point 3.Apply the condition of statical equilibrium to find(a)the actuating force,(b)the torque, and(c)the support reactions.Miscellaneous clutches include several types, such as the

positive-contact clutches, overload-release clutches, overrunning clutches, magnetic fluid clutches, and others.A positive-contact clutch consists of a shift lever and two jaws.The greatest differences between the various types of positive clutches are concerned with the design of the jaws.To provide a longer period of time for shift action during engagement, the jaws may be ratchet-shaped, or gear-tooth-shaped.Sometimes a great many teeth or jaws are used, and they may be cut either circumferentially, so that they engage by cylindrical mating, or on the faces of

the mating elements.Although positive clutches are not used to the extent of the frictional-contact type, they do have important applications where

synchronous operation is required.Devices such as linear drives or motor-operated screw drivers must run to definite limit and then come to a stop.An overload-release type of clutch is required for these applications.These clutches are usually spring-loaded so as to release at a predetermined toque.The clicking sound which is heard when the overload point is reached is considered to be a desirable signal.An overrunning clutch or coupling permits the driven member of a machine to “freewheel” or “overrun” because the driver is stopped or because another source of power increase the speed of the driven.This type of clutch usually uses rollers or balls mounted between an outer sleeve and an inner member having flats machined around the periphery.Driving action is obtained by wedging the rollers between the sleeve and the flats.The clutch is

therefore equivalent to a pawl and ratchet with an infinite number of teeth.Magnetic fluid clutch or brake is a relatively new development which has two parallel magnetic plates.Between these plates is a lubricated magnetic powder mixture.An electromagnetic coil is inserted somewhere in the magnetic circuit.By varying the excitation to this coil, the shearing strength of the magnetic fluid mixture may be accurately controlled.Thus any condition from a full slip to a frozen lockup may be obtained.11

第三篇：畢業(yè)論文外文翻譯

經(jīng)濟(jì)增速放緩對(duì)中國(guó)銀行業(yè)的影響顯現(xiàn) Lagging Indicators: China's Banks and the Slowdown

摘要: Chinese banks' net income surged to record highs last year, defying the slowing growth on the world's second-largest economy.Is it indicating that banks are resilient to the economic downturn?Not nec...Chinese banks' net income surged to record highs last year, defying the slowing growth on the world's second-largest economy.Is it indicating that banks are resilient to the economic downturn?

Not necessarily.The banks have a tendency to be lagging indicators.Only after a certain amount of time has passed will China's macro situation show up on the bottom line.Take, for example, bad loans.They're finally growing, incrementally, after years of declining.Industrial & Commercial Bank of China Ltd., the nation's largest bank by assets, saw its

nonperforming loans rise by 3.82 billion yuan(about $606 million)in the fourth quarter;China Construction Bank Corp., the No.2 bank on the mainland, reported a 6.27 billion yuan rise in such loans.Bank of China Ltd.'s bad loans in the fourth quarter rose 1.39 billion yuan.(In China, nonperforming loans are those that have at least a 30% chance of turning sour.)

Smaller banks also saw some increases in bad loans.China Minsheng Banking Corp., the

country's largest non-state-owned bank, posted a rise of 200 million yuan in nonperforming loans in 2011.Such loans at Industrial Bank Co.grew by 99 million yuan last year.More tellingly, data from the Chinese banking regulator showed that the nonperforming loan ratio in the nation's banking sector edged up 0.1 percentage point in the fourth quarter from the third quarter, the first rise in the past six years.The regulator didn't give a reason, but the earnings reports from Chinese banks this week offered some cues: The property market might be the culprit.China Construction Bank said among the total, its nonperforming loans related to the real estate sector surged 20% over the same period.Minsheng Bank said the nonperforming ratio of its real estate financing businesses was 1.72%, well above its overall bad loan ratio of 0.63%.Home prices have been under pressure for about two years, but it's only now do we see a sign of it in banks' statements.The question is whether investors see a few more problem numbers down the road.In three years starting 2009, banks in China issued a total of 25 trillion yuan of

renminbi-denominated loans, with roughly 40% of the lending going to government-initiated infrastructure projects and the property sector.'The second quarter of this year will be one of the peak seasons for the repayment of property loans and local government borrowings.With a slowing economy, we can expect that higher nonperforming loans are on the cards,' GF Securities analyst Mu Hua said in a recent note.According to Noah Wealth Management, a Chinese financial service company, a total of 117.25 billion yuan of property trust products will be due this year, well above the 47.05 billion yuan last year, putting huge pressure on property developers' cash flows.Besides property, analysts say local government borrowings will present a bigger challenge to banks.Banking executives have estimated that a third of China's 10.7 trillion yuan government debt will be due this year and the next.Standard & Poor's analyst Liao Qiang said he believes Beijing will likely give some regulatory forbearance to local government debt to prevent a surge in banks' bad loans.'Nevertheless, property developers and manufacturers in industries with a supply glut will continue to face policy-induced refinancing uncertainties from time to time,' he said.Monday in Hong Kong, China Construction Bank Chairman Wang Hongzhang said he's optimistic about the bank's asset quality, given China's economic growth is likely to remain solid.'Nonperforming loan levels are controllable.Even though they are higher than before, the amount is small and [the rise] is likely to be temporary,' he said.Agence France-Presse/Getty Images

中資銀行凈利潤(rùn)去年創(chuàng)下新高，似乎并沒有受到中國(guó)這一世界第二大經(jīng)濟(jì)體經(jīng)濟(jì)增速放緩的影響。這是否意味著，銀行業(yè)可以免受經(jīng)濟(jì)下行的影響呢？

未必。

銀行業(yè)的反應(yīng)往往有一定的滯后性。只有在一段時(shí)期后，中國(guó)宏觀經(jīng)濟(jì)形勢(shì)的影響才會(huì)在銀行的營(yíng)收中有所體現(xiàn)。

以不良貸款為例。在下降趨勢(shì)持續(xù)了幾年之后，不良貸款的比例終于開始上升，雖然漲幅不大。按資產(chǎn)總量計(jì)算，中國(guó)最大的銀行中國(guó)工商銀行(Industrial & Commercial Bank of China Ltd.)的不良貸款去年第四季度增加了人民幣38.2億元（約合6.06億美元），中國(guó)第二大銀行中國(guó)建設(shè)銀行(China Construction Bank Corp.)的不良貸款增加了人民幣62.7億元。中國(guó)銀行(Bank of China Ltd.)的不良貸款在第四季度增加了13.9億元。（在中國(guó)，不良貸款指的是變成壞賬的幾率在30%以上的貸款。）

規(guī)模較小銀行的不良貸款水平也在增長(zhǎng)。中國(guó)最大的非國(guó)有銀行中國(guó)民生銀行(China

Minsheng Banking Corp.)2011年不良貸款增加了人民幣2億元。興業(yè)銀行(Industrial Bank Co.)的不良貸款去年增加了人民幣9,900萬元。

更能說明這一問題的是，中國(guó)銀監(jiān)會(huì)的數(shù)據(jù)顯示，中國(guó)銀行業(yè)的不良貸款比例在第四季度較第三季度上升了0.1個(gè)百分點(diǎn)，這是該比例過去六年來首次上升。

銀監(jiān)會(huì)沒有給出原因，但是中資銀行本周發(fā)布的年報(bào)提供了一些線索：房地產(chǎn)市場(chǎng)可能是罪魁禍?zhǔn)住?/p>

中國(guó)建設(shè)銀行表示，在該銀行的所有不良貸款中，與房地產(chǎn)業(yè)有關(guān)的不良貸款同比上漲了20%。民生銀行說，其房地產(chǎn)融資業(yè)務(wù)的不良貸款比例為1.72%，大大超過了其0.63%的總體不良貸款比例。

兩年來住房?jī)r(jià)格一直在承受壓力，但直到現(xiàn)在我們才在銀行的年報(bào)中看到了相關(guān)跡象。問題是，投資者是否看到了更多問題數(shù)據(jù)出現(xiàn)的可能性。

從2009年到2011年這三年里，中資銀行共發(fā)放了25萬億元以人民幣計(jì)價(jià)的貸款，其中約有40%的貸款流向了政府主導(dǎo)的基建項(xiàng)目和樓市。

今年的第二季度將是房地產(chǎn)貸款和地方政府借貸的還款高峰期。廣發(fā)證券(GF Securities Co.)分析師沐華在最近的一份報(bào)告中說，由于經(jīng)濟(jì)減速，我們預(yù)計(jì)可能出現(xiàn)更多的不良貸款。

中國(guó)的金融服務(wù)公司諾亞財(cái)富投資管理有限公司(Noah Private Wealth Management, 簡(jiǎn)稱：諾亞財(cái)富)說，共有1,172.5億元的房地產(chǎn)信托產(chǎn)品將會(huì)在今年到期，高于去年的470.5億元，這給房地產(chǎn)開發(fā)商的現(xiàn)金流造成了巨大壓力。

分析人士說，除了房地產(chǎn)，地方政府借的貸款將為銀行帶來更大的挑戰(zhàn)。據(jù)一些銀行高管估計(jì)，中國(guó)10.7萬億元的政府貸款中，有三分之一將在今明兩年到期。

標(biāo)準(zhǔn)普爾(Standard & Poor)的分析師廖強(qiáng)說，中國(guó)中央政府可能會(huì)給予地方政府債務(wù)一定的寬限，以防不良貸款激增。他說，盡管如此，房地產(chǎn)開發(fā)商以及供應(yīng)過剩行業(yè)的制造企業(yè)仍會(huì)不時(shí)地面臨由政策引發(fā)的再融資不確定性。

中國(guó)建設(shè)銀行董事長(zhǎng)王洪章周一在香港說，考慮到中國(guó)經(jīng)濟(jì)很可能繼續(xù)保持穩(wěn)定增長(zhǎng)，他對(duì)該銀行的資產(chǎn)質(zhì)量持樂觀態(tài)度。他說，不良貸款的水平是可控的。即使是比以往有所增加，總量還是很小，而且增長(zhǎng)很可能也是暫時(shí)的。

第四篇：畢業(yè)論文外文翻譯

外文翻譯：

安全評(píng)估和風(fēng)險(xiǎn)管理方法建設(shè)

張軍，張明元，袁勇波，周靜

（中國(guó)土木與水利工程大學(xué)，大連理工，大連116085）

摘要： 改進(jìn)后的LEC法是用于處理與期貨大廈項(xiàng)目的安全評(píng)估的。經(jīng)修訂的評(píng)估項(xiàng)目L的危險(xiǎn)方法隱藏的工作條件，存在由實(shí)驗(yàn)結(jié)果確定了不同價(jià)值體系之間的能源和人工能源，表明該方法的科學(xué)性和實(shí)用性，并能提高安全成本的經(jīng)濟(jì)效率。

關(guān)鍵詞：建設(shè)危害，安全評(píng)價(jià)，安全管理

1建筑的危害和安全評(píng)估

建筑存在的危險(xiǎn)性都和周圍的建設(shè)用地有關(guān)系。這些條件不合理造成的勘查施工前和施工期間的經(jīng)濟(jì)活動(dòng)不合理并會(huì)轉(zhuǎn)移到危險(xiǎn)性上。首先，它是認(rèn)識(shí)到科學(xué)和危害之后而確定安全管理的必要，進(jìn)行任何監(jiān)測(cè)都有可能發(fā)生意外。

評(píng)估的目的是尋找出安全分析和預(yù)測(cè)危險(xiǎn)的方法，而且其結(jié)果與現(xiàn)有工程或一個(gè)系統(tǒng)，都需要合理并可行。因此我們提出了從監(jiān)督監(jiān)測(cè)和抵御風(fēng)險(xiǎn)中得到的情況，以求意外事故有最低發(fā)生率，這是不同的方法之間的安全評(píng)估和正常的安全管理和監(jiān)控。這樣做的安全評(píng)估、分析、論證和可能的損失建筑工程有關(guān)的傷害和影響范圍都最小。

安全文化是伴隨人類的生產(chǎn)活動(dòng)而產(chǎn)生的。但是，人類有意識(shí)地發(fā)展安全文化，還是近1 0余年的事，國(guó)際原子能機(jī)構(gòu)在對(duì)1 9 8 6年發(fā)生的切爾諾貝利核泄漏事故調(diào)查分析的基礎(chǔ)上，于1 9 9 1年編寫的“7 5一工N 8 A G-4 "評(píng)。報(bào)告首次提出了“安全文化”的概念，并建立了一套核安全文化建設(shè)的思想和策略。

安全文化從核安全文化、航空航天安全文化等企業(yè)安全文化，拓寬到全民安全文化，由此發(fā)展到了由安全觀念文化、安全行為文化、安全物質(zhì)文化組成的全民安全文化的新時(shí)代。在該階段，安全教育體系正在形成，兒童和，}，小學(xué)生的安全教育已經(jīng)起步。大學(xué)和成人的專業(yè)化安全教育已初具規(guī)模，在有關(guān)政府機(jī)

構(gòu)領(lǐng)導(dǎo)下的安全文化普及教育正蓬勃發(fā)展;安全科學(xué)作為獨(dú)立的學(xué)科體系已經(jīng)建立，安全科學(xué)形成了由安全科學(xué)技術(shù)基礎(chǔ)學(xué)科、安全學(xué)、安全工程等構(gòu)成的多學(xué)科體系;安全管理機(jī)構(gòu)進(jìn)一步健全，建立健全了一大批國(guó)際的、國(guó)家的、行業(yè)的、社會(huì)的、企業(yè)的安全管理機(jī)構(gòu);在法規(guī)、標(biāo)準(zhǔn)、安全制度方而，體現(xiàn)在而向全民的安全建設(shè)開始起步，而向行業(yè)的、企業(yè)的安全法規(guī)、標(biāo)準(zhǔn)、制度、操作規(guī)程等具有更強(qiáng)的針對(duì)性，在安全宣傳方而，一個(gè)社會(huì)化的安全宣傳網(wǎng)正在形成，出現(xiàn)了一些而向大眾、宣傳安全光榮、安全就是效益的作品，“安全第一，頂防為主”的安全哲學(xué)思想更加深入人心。

“安全文化是人類文化的部分，它涉及人類活動(dòng)的各個(gè)領(lǐng)域，存在于社會(huì)生活的各個(gè)方而;它涉及自然科學(xué)和社會(huì)科學(xué)的諸學(xué)科，它為安全的世界觀和方法論的形成提供乳育的胚胎，它既具有歷史的繼承性，又具有鮮明的時(shí)代感”。安全文化是燦爛的，華民族文化的組成部分，華民族在生存和繁衍，}，與世界其他民族一起創(chuàng)造并傳播了安全文化。安全文化在我國(guó)的發(fā)展也經(jīng)歷了人類對(duì)安分與健康的臺(tái)目追求、核安全文化出現(xiàn)、全民安全文化的興起等二個(gè)階段。2危險(xiǎn)方法評(píng)估工作

考慮到人的危險(xiǎn)在工作條件，格雷厄姆和吉爾伯特。樓金尼建議的頻率和嚴(yán)重程度，以該評(píng)估環(huán)境和一些揭露應(yīng)指環(huán)境變量作為獨(dú)立設(shè)置的函數(shù)公式。根據(jù)他們的實(shí)際經(jīng)驗(yàn)，根據(jù)不同情況獨(dú)立變量的值，給出了三被標(biāo)記的對(duì)象，然后在危害水平也分為公式后的危險(xiǎn)值來計(jì)算。這種方法容易識(shí)別。

D=LEC

其中，D指該商標(biāo)，L是指事故的發(fā)生概率，E和C是指人類正暴露的頻率和在環(huán)境意味著損失。

3管理建設(shè)的危害

建造業(yè)是高風(fēng)險(xiǎn)行業(yè)，需要管理并改善其意外總數(shù)的發(fā)生。政府提出安全建設(shè)模式位“統(tǒng)一的模式，法律監(jiān)督機(jī)構(gòu)負(fù)責(zé)企業(yè)所有安全監(jiān)管，部分群眾以及整個(gè)社會(huì)參與監(jiān)督”。作者假設(shè)如下：

（1）加強(qiáng)安全監(jiān)察，建設(shè)，以確保施工安全的措施費(fèi)組成競(jìng)爭(zhēng)費(fèi)和特殊項(xiàng)目費(fèi)用;建設(shè)行政主管部門應(yīng)加強(qiáng)項(xiàng)目前的審計(jì)。

（2）加強(qiáng)并完善組織建設(shè)施工安全監(jiān)管，成立一個(gè)監(jiān)管組織，其的特點(diǎn)是依法執(zhí)行監(jiān)管任務(wù)。

（3）編制依據(jù)不同專業(yè)的職業(yè)經(jīng)理人的安全的安全生產(chǎn)監(jiān)管部根據(jù)建筑由大小的地盤遵守《組織對(duì)構(gòu)建企業(yè)安全生產(chǎn)和職業(yè)經(jīng)理人準(zhǔn)備》。

（4）發(fā)展項(xiàng)目和危害安全風(fēng)險(xiǎn)評(píng)估，登記項(xiàng)目，消除構(gòu)建社會(huì)安全危害的可能影響。

（5）建立和落實(shí)，檢查系統(tǒng)的支架固定和拆卸起重機(jī)械，成型板，建立和落實(shí)制度，消除危害的技術(shù)，設(shè)備和材料，建立和實(shí)施項(xiàng)目系統(tǒng)研究項(xiàng)目的施工安全。

（6）監(jiān)測(cè)信息系統(tǒng)的致命危害工地使用是高級(jí)電力監(jiān)控。

（7）開展風(fēng)險(xiǎn)規(guī)避。風(fēng)險(xiǎn)規(guī)避是一個(gè)有用的和共同的風(fēng)險(xiǎn)管理策略。當(dāng)認(rèn)識(shí)到嚴(yán)重后果的隱患和風(fēng)險(xiǎn)因素，但沒有可用的措施之前，建設(shè)，施工計(jì)劃可能改變或放棄為避免風(fēng)險(xiǎn)。

（8）建筑企業(yè)要建立和完善安全體系建設(shè)的長(zhǎng)期性，管理和設(shè)備應(yīng)達(dá)到 降低風(fēng)險(xiǎn)損失之和（參考標(biāo)準(zhǔn)：標(biāo)準(zhǔn)JGJ59 一 1999年）。

（9）發(fā)揮媒體的咨詢作用，進(jìn)行系統(tǒng)的安全性評(píng)估、設(shè)計(jì)、安全監(jiān)測(cè)、認(rèn)證和考試，以及意外傷害保險(xiǎn)賠償。

（10）建立工會(huì)公關(guān)，處理緊急項(xiàng)目。

4結(jié)論

本文主要內(nèi)容是考察了管理層在判斷建筑危害中應(yīng)用的安全性評(píng)估方法。以及建設(shè)項(xiàng)目危險(xiǎn)評(píng)價(jià)工作的執(zhí)行情況，我們已確保了致命的危險(xiǎn)事故發(fā)生率為最低。根據(jù)經(jīng)驗(yàn)，可納入危險(xiǎn)管理系統(tǒng)的危險(xiǎn)值為：低于160時(shí)的危險(xiǎn)，否則，它會(huì)被認(rèn)為是不可承受的危險(xiǎn)事故。應(yīng)該充分應(yīng)用現(xiàn)代化的信息技術(shù)來建立和完善

一道預(yù)防和控制系統(tǒng)來檢測(cè)意外事故。以期待應(yīng)用技術(shù)來預(yù)防更多的意外事故發(fā)生。

第五篇：畢業(yè)論文外文翻譯

國(guó)際服務(wù)貿(mào)易：對(duì)進(jìn)口商和出口商的詳細(xì)描述

霍爾格·布仁里奇基婭拉·克里斯庫(kù)勒

摘要：本文提供了一組從事國(guó)際服務(wù)貿(mào)易企業(yè)的一些新穎的特殊案例，采用的獨(dú)特?cái)?shù)據(jù)來自于進(jìn)出口企業(yè)的世界第二大服務(wù)出口國(guó)——英國(guó)。數(shù)據(jù)顯示在英國(guó)只有一小部分的公司從事國(guó)際服務(wù)貿(mào)易，并且行業(yè)分布廣泛，無論從公司規(guī)模、生產(chǎn)力還是公司其他特點(diǎn)來看，該國(guó)服務(wù)貿(mào)易商與其他貿(mào)易商的區(qū)別還是很大的。本文同時(shí)也提供了詳細(xì)的數(shù)據(jù)證明該國(guó)服務(wù)進(jìn)出口商貿(mào)易模式，比如市場(chǎng)供應(yīng)量、每個(gè)市場(chǎng)的出口和進(jìn)口貨值以及在單個(gè)市場(chǎng)銷售總量中所占的份額。本文將運(yùn)用現(xiàn)有的服務(wù)和貨物貿(mào)易理論來對(duì)上述現(xiàn)象進(jìn)行充分的解釋。研究結(jié)果表明，企業(yè)間的異質(zhì)性是服務(wù)貿(mào)易的主要特征。此外，在企業(yè)層面上來講，服務(wù)貿(mào)易與貨物貿(mào)易還是有許多共同點(diǎn)，并由此得出結(jié)論：現(xiàn)存的異質(zhì)性貨物貿(mào)易公司模型同樣也能夠作為很好的出發(fā)點(diǎn)來解釋相關(guān)的服務(wù)貿(mào)易。

關(guān)鍵字：國(guó)際服務(wù)貿(mào)易，企業(yè)層次解析

1、引言

服務(wù)貿(mào)易一直是國(guó)際貿(mào)易發(fā)展過程中增長(zhǎng)最快的部分，20世紀(jì)90年代初以 來，服務(wù)貿(mào)易以將近10%的年增長(zhǎng)率快速增長(zhǎng)，在2006年服務(wù)貿(mào)易的總出口量達(dá)到了2800億美元（根據(jù)世界貿(mào)易組織，2008年）。在同一時(shí)期，服務(wù)的內(nèi)容也迅速轉(zhuǎn)向以高新技術(shù)密集型為代表的新類別。比如引起激烈討論的服務(wù)外包等商業(yè)服務(wù)類。一般來說，鑒于發(fā)達(dá)經(jīng)濟(jì)體服務(wù)行業(yè)的未來發(fā)展趨勢(shì)以及重要性，服務(wù)貿(mào)易自由化在過去以及現(xiàn)在都被作為貿(mào)易談判的重要環(huán)節(jié)并不會(huì)讓人們感到奇怪。

盡管如此，我們還是發(fā)現(xiàn)很少的公司從事服務(wù)貿(mào)易行業(yè)。這與貨物貿(mào)易的相關(guān)研究形成了鮮明的對(duì)比，貨物貿(mào)易的相關(guān)研究為出口國(guó)提供了很多鮮明的實(shí)例，最近研究表明，貨物貿(mào)易的相關(guān)研究同樣也能為進(jìn)口企業(yè)提供有效的實(shí)例。這些企業(yè)都是大型的，生產(chǎn)力很高的企業(yè)，企業(yè)使用了更多的資本密集型的生產(chǎn)工序，還聘請(qǐng)了高技能勞動(dòng)力（詳見貝爾納，杰森，1995,1999；貝爾納等，2007；瓦格內(nèi)爾，2007；格林納威，科內(nèi)爾勒，2007）。此文獻(xiàn)的數(shù)據(jù)也表明，部分企業(yè)的貨物出口額常常很低。即使在出口商中，大部分的公司只會(huì)在很少的幾個(gè)國(guó)外市場(chǎng)進(jìn)行貿(mào)易，并把自己的主要銷售目標(biāo)放在了國(guó)內(nèi)市場(chǎng)（貝爾納，杰森，1999；伊頓等，2004；貝爾納等，2009）。這些研究同樣激發(fā)了更多學(xué)者推出更多的理論文獻(xiàn)，并通過許多嘗試將這些事例融入不同的理論框架（例如：梅利茲，2003；貝爾納等，2003,2009；伊頓等，2008）。

本文通過對(duì)2000年——2005年在英國(guó)服務(wù)貿(mào)易進(jìn)出口的兩個(gè)獨(dú)特的企業(yè)級(jí)數(shù)據(jù)的分析，我們首次為從事服務(wù)貿(mào)易的公司提出了一套可比的程式化事例。這些數(shù)據(jù)的第一個(gè)受訪者資料（ARD）包含了企業(yè)級(jí)服務(wù)進(jìn)出口貿(mào)易的價(jià)值信息以及相關(guān)附加變量的取值范圍，同時(shí)，這也做為英國(guó)的民營(yíng)企業(yè)的樣本象征。這能使我們能夠輕易區(qū)分服務(wù)進(jìn)出口公司以及不從事服務(wù)貿(mào)易的公司，也能讓我們能夠分析這些群體之間的差異性。我們還將ARD與ITIS（國(guó)家貿(mào)易服務(wù)查詢）進(jìn)行結(jié)合。因?yàn)镮TIS能夠提供更多詳細(xì)的服務(wù)貿(mào)易公司信息。比如：與該國(guó)進(jìn)行貿(mào)易的國(guó)家以及該國(guó)服務(wù)進(jìn)出口貿(mào)易模式。

我們將使用這兩套數(shù)據(jù)以及一些其他附加的原始數(shù)據(jù)來描繪出英國(guó)服務(wù)進(jìn)

出口的貿(mào)易特點(diǎn)和貿(mào)易模式。我們的首要目標(biāo)是改進(jìn)現(xiàn)有的關(guān)于服務(wù)貿(mào)易的相關(guān)理論文獻(xiàn)。以下詳細(xì)提及描述的文獻(xiàn)，目前要么完全倚靠完全競(jìng)爭(zhēng)或者壟斷競(jìng)爭(zhēng)理論框架要么完全依靠具有代表性的公司。研究表明，這種抽象略看企業(yè)異質(zhì)性的顯著水平，使得我們難以了解國(guó)際服務(wù)貿(mào)易的一些重要方面。本文的第一部分主要從更加詳細(xì)的方面分析了企業(yè)的異質(zhì)性，同時(shí)還提供了提套經(jīng)驗(yàn)規(guī)律，可以使得未來具有異質(zhì)性的服務(wù)貿(mào)易的公司模型能夠復(fù)制。我們主要將以兩個(gè)步驟來使得上述企業(yè)級(jí)貨物貿(mào)易在經(jīng)驗(yàn)規(guī)律文獻(xiàn)下能夠慢慢地有序發(fā)展。

第一步是使用ARD來識(shí)別英國(guó)的公司里的服務(wù)貿(mào)易進(jìn)出口商，然后將這些服務(wù)貿(mào)易商與不從事服務(wù)貿(mào)易的企業(yè)進(jìn)行比較。在第二個(gè)步驟中，我們會(huì)將ARD以及ITIS的相關(guān)數(shù)據(jù)進(jìn)行結(jié)合分析，以便不僅能夠了解進(jìn)出口狀況，也能夠?qū)氖路?wù)貿(mào)易的企業(yè)的貿(mào)易模式提供更多的細(xì)節(jié)。

為了今后的理論工作提供投入，我們對(duì)于研究結(jié)果的政策影響也十分感興趣。例如：我們的研究結(jié)果有助于我們了解過去和未來的服務(wù)貿(mào)易實(shí)施自由化的后果。類似貨物貿(mào)易自由化，服務(wù)貿(mào)易自由化可能導(dǎo)致純粹的國(guó)內(nèi)企業(yè)的市場(chǎng)份額，以及從事服務(wù)貿(mào)易的企業(yè)變化。研究發(fā)現(xiàn)，進(jìn)口商和出口商的許多公司特點(diǎn)（生產(chǎn)力，技術(shù)密集度等）與國(guó)內(nèi)企業(yè)不同，本文建議在服務(wù)貿(mào)易自由化之后，增加總的生產(chǎn)率和技能的需求將有重要的意義。

2、文獻(xiàn)綜述

關(guān)于服務(wù)貿(mào)易的理論文獻(xiàn)中占主導(dǎo)地位的主題是分從貿(mào)易不同的程度來看，析服務(wù)貿(mào)易與貨物貿(mào)易有哪些不同，以及如何影響先前的貨物貿(mào)易理論成果。比如：希爾（1977）認(rèn)為，大多數(shù)服務(wù)的主要特點(diǎn)是要求聯(lián)合生產(chǎn)必須同時(shí)消費(fèi)和生產(chǎn)。因?yàn)榉?wù)不能儲(chǔ)存，對(duì)于一項(xiàng)交易來說，生產(chǎn)者和消費(fèi)者都必須是現(xiàn)行的，服務(wù)交易必須發(fā)生在同一時(shí)間，可能的話應(yīng)該發(fā)生在同一地點(diǎn)。迪爾朵夫（1985年）和梅爾文（1989）認(rèn)為法律服務(wù)貿(mào)易的比較優(yōu)勢(shì)功能可能失效，或至少需要重新解釋。米爾扎和尼科萊蒂（2004）指出，進(jìn)行聯(lián)合生產(chǎn)時(shí)取得的從出口國(guó)和進(jìn)口國(guó)的投入通常需要服務(wù)貿(mào)易。

在引力方程框架的基礎(chǔ)上，過去十年的服務(wù)貿(mào)易的工作經(jīng)驗(yàn)同樣也增加了。這些貨物貿(mào)易文獻(xiàn)論文缺乏詳細(xì)的微觀層面的數(shù)據(jù)，也沒有分析國(guó)家或行業(yè)服務(wù)貿(mào)易的總體水平數(shù)據(jù)（如弗氏和文候得，木村和李。2002年，2006;海德，2009）這些研究結(jié)果是與貨物貿(mào)易的相關(guān)研究是類似。例如海德等（2009）和木村和李（2006）估計(jì)可比較的貨物和服務(wù)貿(mào)易細(xì)則以及找到類似的彈性估計(jì)。海德，邁耶和里斯還表明，其他變量在貨物貿(mào)易的重力回歸被發(fā)現(xiàn)，比如共同的語言或共享的殖民地起源，都會(huì)相應(yīng)地增加商品和服務(wù)貿(mào)易。

3、定義和數(shù)據(jù)描述

在本節(jié)中，我們描述的企業(yè)級(jí)數(shù)據(jù)服務(wù)進(jìn)口和出口，并使用額外的變量。我們首先解釋在本文中國(guó)際服務(wù)貿(mào)易的定義，然后說明我們的主要數(shù)據(jù)來源，以及它們是如何與我們分析的目的相結(jié)合的。附錄A包含更多細(xì)節(jié)上的數(shù)據(jù)。

3.1 國(guó)際服務(wù)貿(mào)易的定義

在這篇論文中，服務(wù)貿(mào)易的定義是根據(jù)國(guó)際貨幣基金組織（IMF）的國(guó)際收支平衡手冊(cè)的基本定義（第5版），在英國(guó)收支平衡統(tǒng)計(jì)的平衡的基礎(chǔ)上被編譯（見國(guó)際貨幣基金組織，1993）。因此，國(guó)際服務(wù)貿(mào)易是指一個(gè)經(jīng)濟(jì)體系的居民和非居民之間的服務(wù)交易。

3.2 數(shù)據(jù)來源

3.2.1 受訪者資料庫(kù)

我們的第一個(gè)主數(shù)據(jù)源是受訪者資料庫(kù)（ARD），這是基于英國(guó)國(guó)家統(tǒng)計(jì)局的一項(xiàng)強(qiáng)制性對(duì)英國(guó)企業(yè)進(jìn)行的調(diào)查，并且英國(guó)的受訪者資料庫(kù)也是相當(dāng)于美國(guó)的縱向受訪者數(shù)據(jù)庫(kù)的。ARD是基于英國(guó)每年超過40,000私營(yíng)部門的公司的一個(gè)分層抽樣，小型企業(yè)和大型企業(yè)的全面隨機(jī)抽樣（根據(jù)今年的那些員工超過100或250）。ARD的包含了其他變量，比如：就業(yè)信息，投資，中間投入，增加值，總產(chǎn)出，行業(yè)隸屬關(guān)系，企業(yè)位置和外國(guó)所有權(quán).本文還包括對(duì)跨國(guó)公司的地位從外商直接投資的注冊(cè)信息，（見克里斯庫(kù)勒和馬丁，2009）。

3.2.2 國(guó)際貿(mào)易的咨詢服務(wù)

第二大信息的主要來源是國(guó)際貿(mào)易查詢服務(wù)（ITIS），ITIS也是由國(guó)家統(tǒng)計(jì)局進(jìn)行的。它收集的國(guó)際交易數(shù)據(jù)是來自于英國(guó)本土的私營(yíng)部門公司的服務(wù)和服務(wù)帳戶（統(tǒng)計(jì)局，2007），同樣也是英國(guó)國(guó)際收支的平衡貿(mào)易的主要投入。ITIS調(diào)查的公司一般都擁有10個(gè)或更多的員工。此項(xiàng)調(diào)查是法定的，是在上季度和上的基礎(chǔ)上進(jìn)行。我們充分結(jié)合了這兩種查詢方式。自2001年以來，我們每年已經(jīng)采樣了已超過20,000公司（2001年之前為10,000）。

3.2.3 第三代客戶綜合系統(tǒng)創(chuàng)新調(diào)查

我們運(yùn)用了第三代客戶綜合系統(tǒng)創(chuàng)新調(diào)查（CIS3），其中包括1998-2000年期間所得到企業(yè)的出口貨物，高技能，并被當(dāng)做衡量畢業(yè)生在勞動(dòng)力中所占的比例信息的數(shù)據(jù)。這是唯一可用的統(tǒng)計(jì)局的數(shù)據(jù)集，其中包含對(duì)這些變量的直接信息。類似于ARD的服務(wù)貿(mào)易，CIS3提供了一個(gè)企業(yè)的出口狀態(tài)的和出口貨物的總價(jià)值的信息，但不是具體的產(chǎn)品出口或出口目的地。CIS3是基于分層隨機(jī)抽樣，來調(diào)查約20000個(gè)左右的制造業(yè)和服務(wù)業(yè)的英國(guó)企業(yè)。這項(xiàng)調(diào)查包含貨物在1998年和2000年出口的信息，以及2000年的技能信息。

3.3 樣本組合和描述性統(tǒng)計(jì)

在本文的其它部分，我們將使用這三種調(diào)查的不同組合。所有這三個(gè)數(shù)據(jù)集包含常見的公司標(biāo)識(shí)，因而很容易合并。我們首先使用ARD的數(shù)據(jù)對(duì)服務(wù)貿(mào)易商的特點(diǎn)和非貿(mào)易商進(jìn)行比較（4.1節(jié)）。在4.1節(jié)中，貿(mào)易商技能服務(wù)以及讀物和商品出口商的比較結(jié)果是基于合并后的ARD數(shù)據(jù)以及2000年的CIS3數(shù)據(jù)。通過結(jié)合該的ARD和CIS3數(shù)據(jù)，我們獲得了出口服務(wù)商樣本所包含的信息（來源于ARD），貨物出口和企業(yè)技能強(qiáng)度（來源于CIS3），以及其他企業(yè)級(jí)的變量，比如就業(yè)和生產(chǎn)力的（來源于ARD）。

4、服務(wù)貿(mào)易商的特殊事例

接下來，本文將提出服務(wù)的出口商和進(jìn)口商的特殊事例。我們首先關(guān)注的服務(wù)貿(mào)易商和非服務(wù)貿(mào)易商的比較（4.1節(jié)）。然后，我們描述了現(xiàn)有的服務(wù)商的貿(mào)易模式并提出了解釋在企業(yè)級(jí)和總服務(wù)貿(mào)易的變化和密集廣泛的利率的重要性（4.2節(jié)）。最后，我們?cè)诿恳粋€(gè)部分都做了小結(jié)，以便未來研究可能的討論和經(jīng)濟(jì)政策影響。

因此，貨物貿(mào)易的異構(gòu)的企業(yè)模型似乎也成為了提供了解釋服務(wù)貿(mào)易的微觀模式的一個(gè)很好的開始點(diǎn)。這也許是不奇怪，因?yàn)槲覀兊难芯拷Y(jié)果和上述討論在貨物貿(mào)易文獻(xiàn)相比較的事實(shí)之間的存在相似性。然而，我們還注意到一個(gè)服務(wù)貿(mào)易模式的一些有趣的特殊性，比如服務(wù)商似乎主要是沿著較高的利潤(rùn)率擴(kuò)大出口和進(jìn)口的事實(shí)。再次，我們認(rèn)為，這些分歧不要求對(duì)貨物貿(mào)易的現(xiàn)有模式的重大

修改，雖然他們可能意味在關(guān)鍵的參數(shù)值中重要的定量差異，比如市場(chǎng)準(zhǔn)入或變量的貿(mào)易成本。

5、結(jié)論

在本文中，本文使用了英國(guó)的出口和進(jìn)口在2000-2005年期間獨(dú)特的企業(yè)級(jí)數(shù)據(jù)，為從事國(guó)際服務(wù)貿(mào)易的企業(yè)提供了一套的特殊事例。從這些事例中出現(xiàn)的兩個(gè)主要結(jié)果一個(gè)是在企業(yè)級(jí)的服務(wù)貿(mào)易中的異質(zhì)性很強(qiáng)，有時(shí)與貨物貿(mào)易文獻(xiàn)中找到的數(shù)據(jù)模式有驚人的相似。另一個(gè)就是使企業(yè)異質(zhì)性納入現(xiàn)有模式的服務(wù)。這對(duì)于獲取服務(wù)出口和進(jìn)口的關(guān)鍵方面是十分有必要的。貨物貿(mào)易的現(xiàn)有模式應(yīng)該是這樣做的一個(gè)極好的出發(fā)點(diǎn)，即使有可能使用一些必要的修改來解釋在整篇論文所強(qiáng)調(diào)貨物和服務(wù)貿(mào)易之間的差異。