本科毕业论文--外文资料与中文翻译（5篇范例）

第一篇：本科毕业论文--外文资料与中文翻译

河南理工大学万方科技学院本科毕业论文

附录：

外文资料与中文翻译

外文资料：

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.河南理工大学万方科技学院本科毕业论文

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 河南理工大学万方科技学院本科毕业论文

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

河南理工大学万方科技学院本科毕业论文

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

河南理工大学万方科技学院本科毕业论文

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

河南理工大学万方科技学院本科毕业论文

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

河南理工大学万方科技学院本科毕业论文

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

河南理工大学万方科技学院本科毕业论文

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.河南理工大学万方科技学院本科毕业论文

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.河南理工大学万方科技学院本科毕业论文

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

河南理工大学万方科技学院本科毕业论文

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.河南理工大学万方科技学院本科毕业论文

中文翻译：

煤矿安全

在历史上，煤矿开采一直是危险的行业。但是，在近几年中，人们在减少煤矿伤亡事故方面取得了巨大的进步。主要有以下几个方面： ⑴ 矿井通风安全

矿山通风的目标：

• 从工程技术来讲，正确控制矿山空气需要：

• 提供新鲜的空气（氧气）工，供人呼吸； • 提供氧气来源，供给各种机械上的内燃机； • 稀释空气中的污染物，以达到允许标准； • 保持空气的温度和湿度在容许的界限内； • 除去空气当中来自矿山的污染物。

矿山通风的目标有两部分内容：首先，维持生命；其次，带走有毒的气体。矿山通风在历史上重要的角色是提供足量的新鲜空气，以代替井下工作的矿工所消耗的氧气。现今，矿山通风主要对付有害的气体（主要由无轨设备产生）。

在煤矿开采的早期，人们已用金丝雀来检测瓦斯。这种敏感的鸟带到工作地点，如果发现它死亡了，矿工将立即离开矿井。20世纪20年代，手工转动的风机被小型的空气动力涡轮风机所取代。大型的抽出式风机安置在地表，并且其尺寸在逐渐增加。地面的压缩机把风流通过管道压入矿井中，供给动力机械和辅助通风。

除非给工作面分配了合适的风量，否则矿井通风系统就没有完成它的主要任务。虽然人们普遍认识到通风的这个最终任务是极其重要的，河南理工大学万方科技学院本科毕业论文

但是要完成这个任务也是极其困难的。

图1也表示出了产生和控制风流的主要方法。主要通风机，单独或联合运行，控制流经整个系统的所有风流。主要通风机通常（但不是必须的）安置在地面，或者如图1所示的那样抽出风流流过系统，或者与进风竖井或主要进风道相连，压入风流进入和流经系统。由于煤矿瓦斯和粉尘都可能爆炸，这是其他地下设施所不具有的危害，所以煤矿的保障通风的法规比其他地下设施要严格。许多国家的法规

Figure 1.Typical elements of a main

ventilation system 规定，煤矿中的主要通风机必须安置在地面，并且还有其他一些限制，例如不安装在和竖井或巷道呈直线的位置，配备冲击板（防爆门）以在煤矿发生爆炸时，起到保护风机的作用。

风墙和密闭：矿山在开采过程中，进风和回风之间需要一些连接设施。当巷道不再需要通过或通风，那么应用风墙封闭，以防止风流短路。构筑风墙的材料为砖石、混凝土或耐火木材。另外，也使用预先制成的钢制风墙。风墙应充分楔入顶板、地板和四周，尤其当岩层松软或者煤矿易发生自燃的情况下。在风墙压力高的一面涂上一层密封剂，并特别注意其周界，那么漏风会减少。这里同样，在松软和化学活性强的岩层中，这种涂层应延伸到岩层表面距风墙后面几米处。在风路易于集中的情况下，应采取预防措施来保护风墙，以避免过早出现故障或者破裂。这些措施从在风墙的顶部安置压垫到在预制风墙上安置滑动的或可变形

河南理工大学万方科技学院本科毕业论文 的面板。在所有情况下，风墙的组成成分是防火的，当加热时不应产生有毒烟气。

作为一种短期措施，风障帘被固定在顶板、四周和底板，形成一种临时密闭，这用于压差小的地方，例如开采区域的附近位置。

当矿井报废区域需要同现有基本通风结构隔离，应在连接风道的入口处构造密闭。如果要求密闭具有防爆性，它们应由两个或多个间距为5~10米的风墙组成，在风墙之间的区域填充沙、石粉、紧密的不燃岩石废料、以水泥为基础的填充物或其他人造材料。钢梁架在顶板和底板之间，以增加结构强度。用薄灰浆填塞岩层周围，增加了松软地面上密闭的完整性。煤矿中，矿业法规或谨慎的安全考虑可能要求密闭为防爆的。

风门和风闸：当进风和回风之间必须通行时，在风墙上应安装一个通风门。最简单的形式是装有铰链的木制或钢制风门，能够在风流压力大的一侧开启。使铰链形成角度补充了这种半关闭特性，从而使风门打开时有轻微地提升，在自身的重力下关闭。建议在风门上安装插销，以防止在压差方向反向的紧急情况下，风门被打开。沿着风门的底部缚上具有特定断面形状的柔韧性条带，有助于减少漏风，尤其当风路上铺有轨道时。

安设在主要进风和回风之间的通风门通常构建为两道或多道，形成了风闸。这防止了当一道风门打开让车辆和人员通行时风流短路。风门之间的距离应能够容纳需通过风闸的交通工具中的最长列车。压差高时，多层风门也使压力突变均分到各风门上。

机械风门由气动力或电力开启，这对于车辆通行尤其方便，对于由于风门尺寸小或空气压力造成手动操作困难的情况下很便利的。机械操作风门也可以是一侧装铰链的形式，还可以呈手工卷制的雪茄烟或六角手风琴形式。它们可以通过拖绳人工操作，也可以自动感觉接近的车辆

河南理工大学万方科技学院本科毕业论文

或人员。大型风门安装有带铰链的小门供人员通行。暴露在较高压差下的人门人工开启可能困难。这种情况下，安装一滑动面板，当风门打开时能暂时减小压差。在风闸上也应采用互锁装置，以阻止所有风门同时被打开。

CFD在通风中的应用：由于计算机处理能力得到了新发展，所以CFD已经被用来解决许多工程学科中大量的规模巨大、结构复杂的流体问题。处理器速度的提高也促使了改良的后处理方法和图解法的发展，可以将这些模型产生的结果可视化。近来的研究工作已经采用CFD模型来描绘在地下矿井网络中风流流动和污染物的分布形式，并通过比例或全尺度的实验验证了其有效性。尤其是Moloney在1997年所作的研究表明：已经验证其有效性的CFD模型能够成功地重现局部通风快速掘进中所观测到的风流流动和污染物的分布形式。已证实CFD是一种有效的方法，可用来确定临界面积区（如工作面）流体的详细特征。这种模型所产生的结果也能表明不同的局部通风结构中，掘进工作面产生的瓦斯和粉尘运送、弥散和稀释的相对效率。1999 年，Moloney等近一步的新研究表明：已经验证的CFD模型可以用来模拟许多不同采矿和通风结构中的气流和污染物的散布数据，每次模拟训练都会产生大量的速度、压力和污染物浓度的数据。⑵ 火灾的控制方法

发生在矿井风巷中的火灾通常开始于一点的燃烧。最初火势非常小，实际上只要能够及时地进行局部处理，大多数火灾都能被立即扑灭。快速的行动是非常重要的。旺盛的燃烧如果未被发现，那么即使只有几分钟，也能够发展为大火，从而很难或者不可能扑灭了。因而，封闭区域或者整个矿井可能变得不可避免了。

如果及时行动，大部分火灾都能够扑灭。火灾探测系统、培训、设

河南理工大学万方科技学院本科毕业论文

计良好的灭火系统和现成的能充分运行的灭火设备很重要。合适型号的灭火器应安置在车辆上面和火灾危险大的所有区域的逆流侧。这包括储藏室区域和设备的固定安装位置（例如电站或压缩机站和运输机的传送机头）。

电力火灾既不能用水也不能用泡沫灭火，除非确定电源已关。使用二氧化碳或干粉的灭火器适于扑灭电力火灾或易燃液体火灾。

洪水和自动喷水系统在固定设备、储藏室和输送机上面这些地区很有效。这些装置要激活应通过热力探测器而不是烟雾或瓦斯探测器，以确保只有当在邻近地区发生明火燃烧时才自动运转。

除了电力和可燃液体火灾外，水是灭火最常用的方法。当水应用在燃烧着表面时，它有助于消除火灾三角形的两个方面。水蒸发时具有的潜在热能和随后水蒸气的热力能帮助消除燃烧物质的热能。此外，水蒸气取代空气并且液体在较凉的表面形成覆盖层，这有助于隔绝氧气。3.粉尘控制方法

减少隧道内和地下矿山中的悬浮粉尘，有三种主要控制方法：通风、水和粉尘捕获器。

通风气流通过稀释和置换作用减少粉尘。当工人处于粉尘云的包围中，稀释过程起作用，附加的气流通过稀释尘云，减少粉尘的浓度。当工人逆着尘源的方向时，置换作用起作用，气流速度足够高以至于可靠地使粉尘保持顺风方向。

① 稀释通风

稀释通风的基本原理是提供更多的空气和稀释粉尘。大多数情况下，减少的粉尘与增加的风量大致成比例，但并不总是这样。增加风量的费用和技术障碍是实际存在的，尤其是流过通风管道或井筒的气流速度已达到3000英尺/f分或更大。

② 置换通风

置换通风的基本原理是利用风流约束尘源，使粉尘沿

河南理工大学万方科技学院本科毕业论文

着工人下风向，从而远离工人。任一隧道或矿山通道中，如风流方向使粉尘沿着工人下风向运动，使用的都是置换通风。在矿山中，回风系统中连续采煤机的表面或隧道钻探机，使用的是置换通风。尘源的周围，例如运输皮带传送处连同周围为多尘空气的采区，是置换通风的又一个例子。置换通风很难实现。然而，如果做得好，置换通风是能利用的最有效的粉尘控制方法，值得付出大量的努力，使其运行良好。困难之处在于：当工人在尘源附近时，比方说10~20英尺，使工人逆着风流需要相当大的风速，典型的是在60到150英尺/分之间。并不总是有足够多的风量能达到这么大的风速。

③ 洒水

开采中洒水的作用是双重的：湿润正被运输的粉碎物质、空中捕获。这两个作用中，湿润粉碎物质非常有效。

适度的湿润对于粉尘控制来说是非常重要的。在粉碎过程中产生的粉尘颗粒大部分没有释放到空气中，而是附着在粉碎物质的表面。湿润破碎的物质能够确保粉尘颗粒保持附着状态。因此，通常认为加的水越多（但并不总是）也能减少粉尘。例如，煤矿操作员已能够通过提高（滚筒式）采煤机的水流速度，来减少长壁开采较高水平的粉尘，以至达到100(每分钟加仑数)。与开采煤的数量相比，以重量为基础，采煤机单独加的湿度100加仑（分）等于1.9%。可惜的是，过高的湿度也能导致许多材料的输送问题，难于操作的问题，产品的质量问题，所以，用水的上限有时能很快的达到。因此，用以替代仅仅增加水量的另外一种方法是确保粉碎的物质能够得到均匀的加湿。⑷ 矿山排水

几乎每一个矿都会有水侵入，侵入形式为：直接降水（雨和雪）；地面迳流（地面流走的水就叫迳流）；地下渗透。涌水对许多开采作业的费用和进展会产生重要的影响，并且在某些情况下能够造成人员伤亡和财

河南理工大学万方科技学院本科毕业论文

产损失。

控制矿山水的方法（矿山排水）：

当井筒或其他矿山巷道延伸到潜水位以下时，很可能遇到水，水渗露到巷道的程度取决于暴露岩层表面的区域、流体静压力和其他因素。为了能够继续开采作业，因此需要通过人工方法降低矿山邻近地区的地层水位，保持巷道内无水，同时防止地表水流入到（地表或地下）矿山内。这种操作称为矿山排水。

矿山排水的方法受限于环境条件和客观因素。下面控制矿山水的种类可以单独使用，也可以更有效地联合使用。

① 使井筒或巷道建在最佳的地面上，以防止直接水从地表流入。② 在地表或接近地表处，改变水的流向或者排水。

③ 用特殊类型的水泥、斑脱土（火山灰分解成的一种粘土)和液体化学浆（水填充物）进行注浆，以降低岩石块的渗透性。

④ 为探测钻孔下套管或用水泥涂探测钻孔。

⑤ 只要可能有突水，其速率可能不方便接近的地方，开采前打引水孔。

⑥ 通过疏水井和矿井内可利用的地方抽水，以降低岩床水位。⑸ 矿工听力损失和保护听力的方法

每个人都知道采矿业是一个嘈杂的行业，但你听力损失的可能性是从事安静工作人员的九倍还多，这个你知道吗？如果在工作中不保护自己遭受噪音的危害，那么到50岁时，你将可能需要助听器。很显然，最好的办法是从技术上消除噪声，但是通常这并不能马上实现（很难实现）。除非矿山是较安静的，否则只要你周围的噪音具有危害性，帮助你保护及其重要的听觉的一个方法是使用听力防护罩。即使你已损失了部分听力，你也应使用听力防护罩，以阻止听力的进一步恶化。当巨大的噪声

河南理工大学万方科技学院本科毕业论文

存在时，正确使用听力防护罩将有助于矿工预防大多数甚至全部导致听力损失的噪声。

矿主和矿工应一起采取措施，以降低听力永久损失的危险性。在消除噪音危害的战役中，技术控制的方法是第一位的.当矿主和操作员更换或升级设备时，只要可能，应当购买无噪音的设备。许多情况下，声障、隔音材料、封闭的驾驶室或其他噪音控制方法能够降低矿工的噪声接触。但是，如果技术控制方法不能消除噪声危害，那么矿主应当提供听力防护罩。防护罩应满足矿工的特殊需要：舒适、方便、在采矿环境下可用。矿主应该培训矿工如何选择和佩带各种各样的听力防护罩，矿工应当尽心尽责地有效使用这些防护设备。

矿工应该明白：矿山中，他们可以连同其他安全装备来安全地佩带听力防护罩和。事实上，有时听力防护罩使持续的背景噪音减弱，能够帮助矿工听到警告信号、发警报、说话。矿工也应确信：正确的佩带耳塞不会损害他们的耳膜。如果矿工工作中需要相互通话时，可使用内置通信电路的听力防护罩。当矿山环境的噪音断断续续时，这些装置尤为有用。出现一种带有有源电路的防护罩，能够减弱背景噪音，而放大附近的语音。这些电子装置，有些还没有在地下采矿中得到试验证明，但它们已经在地面开采和大规模的建筑行业得到应用。

如果做到这些方面，那么我们的采矿工作将变得更加安全。

第二篇：毕业论文外文翻译

齿轮和轴的介绍

摘 要:在传统机械和现代机械中齿轮和轴的重要地位是不可动摇的。齿轮和轴主要 安装在主轴箱来传递力的方向。通过加工制造它们可以分为许多的型号，分别用于许 多的场合。所以我们对齿轮和轴的了解和认识必须是多层次多方位的。关键词:齿轮；轴 关键词 在直齿圆柱齿轮的受力分析中，是假定各力作用在单一平面的。我们将研究作用 力具有三维坐标的齿轮。因此，在斜齿轮的情况下，其齿向是不平行于回转轴线的。而在锥齿轮的情况中各回转轴线互相不平行。像我们要讨论的那样，尚有其他道理需 要学习，掌握。斜齿轮用于传递平行轴之间的运动。倾斜角度每个齿轮都一样，但一个必须右旋 斜齿，而另一个必须是左旋斜齿。齿的形状是一溅开线螺旋面。如果一张被剪成平行 四边形（矩形）的纸张包围在齿轮圆柱体上，纸上印出齿的角刃边就变成斜线。如果 我展开这张纸，在血角刃边上的每一个点就发生一渐开线曲线。直齿圆柱齿轮轮齿的初始接触处是跨过整个齿面而伸展开来的线。斜齿轮轮齿的 初始接触是一点，当齿进入更多的啮合时，它就变成线。在直齿圆柱齿轮中，接触是平行于回转轴线的。在斜齿轮中，该先是跨过齿面的对角线。它是齿轮逐渐进行啮合 并平稳的从一个齿到另一个齿传递运动，那样就使斜齿轮具有高速重载下平稳传递运 动的能力。斜齿轮使轴的轴承承受径向和轴向力。当轴向推力变的大了或由于别的原 因而产生某些影响时，那就可以使用人字齿轮。双斜齿轮（人字齿轮）是与反向的并 排地装在同一轴上的两个斜齿轮等效。他们产生相反的轴向推力作用，这样就消除了 轴向推力。当两个或更多个单向齿斜齿轮被在同一轴上时，齿轮的齿向应作选择，以 便产生最小的轴向推力。交错轴斜齿轮或螺旋齿轮，他们是轴中心线既不相交也不平行。交错轴斜齿轮的 齿彼此之间发生点接触，它随着齿轮的磨合而变成线接触。因此他们只能传递小的载 荷和主要用于仪器设备中，而且肯定不能推荐在动力传动中使用。交错轴斜齿轮与斜 齿轮之间在被安装后互相捏合之前是没有任何区别的。它们是以同样的方法进行制 造。一对相啮合的交错轴斜齿轮通常具有同样的齿向，即左旋主动齿轮跟右旋从动齿 轮相啮合。在交错轴斜齿设计中，当该齿的斜角相等时所产生滑移速度最小。然而当

该齿的斜角不相等时，如果两个齿轮具有相同齿向的话，大斜角齿轮应用作主动齿轮。蜗轮与交错轴斜齿轮相似。小齿轮即蜗杆具有较小的齿数，通常是一到四齿，由 于它们完全缠绕在节圆柱上，因此它们被称为螺纹齿。与其相配的齿轮叫做蜗轮，蜗 轮不是真正的斜齿轮。蜗杆和蜗轮通常是用于向垂直相交轴之间的传动提供大的角速 度减速比。蜗轮不是斜齿轮，因为其齿顶面做成中凹形状以适配蜗杆曲率，目的是要 形成线接触而不是点接触。然而蜗杆蜗轮传动机构中存在齿间有较大滑移速度的缺 点，正像交错轴斜齿轮那样。蜗杆蜗轮机构有单包围和双包围机构。单包围机构就是蜗轮包裹着蜗杆的一种机 构。当然，如果每个构件各自局部地包围着对方的蜗轮机构就是双包围蜗轮蜗杆机构。着两者之间的重要区别是，在双包围蜗轮组的轮齿间有面接触，而在单包围的蜗轮组 的轮齿间有线接触。一个装置中的蜗杆和蜗轮正像交错轴斜齿轮那样具有相同的齿 向，但是其斜齿齿角的角度是极不相同的。蜗杆上的齿斜角度通常很大，而蜗轮上的 则极小，因此习惯常规定蜗杆的导角，那就是蜗杆齿斜角的余角；也规定了蜗轮上的 齿斜角，该两角之和就等于 90 度的轴线交角。当齿轮要用来传递相交轴之间的运动时，就需要某种形式的锥齿轮。虽然锥齿轮 通常制造成能构成 90 度轴交角，但它们也可产生任何角度的轴交角。轮齿可以铸出，铣制或滚切加工。仅就滚齿而言就可达一级精度。在典型的锥齿轮安装中，其中一个 锥齿轮常常装于支承的外侧。这意味着轴的挠曲情况更加明显而使在轮齿接触上具有 更大的影响。另外一个难题，发生在难于预示锥齿轮轮齿上的应力，实际上是由于齿轮被加工 成锥状造成的。直齿锥齿轮易于设计且制造简单，如果他们安装的精密而确定，在运转中会产生 良好效果。然而在直齿圆柱齿轮情况下，在节线速度较高时，他们将发出噪音。在这 些

情况下，螺旋锥齿轮比直齿轮能产生平稳的多的啮合作用，因此碰到高速运转的场 合那是很有用的。当在汽车的各种不同用途中，有一个带偏心轴的类似锥齿轮的机构，那是常常所希望的。这样的齿轮机构叫做准双曲面齿轮机构，因为它们的节面是双曲 回转面。这种齿轮之间的轮齿作用是沿着一根直线上产生滚动与滑动相结合的运动并 和蜗轮蜗杆的轮齿作用有着更多的共同之处。轴是一种转动或静止的杆件。通常有圆形横截面。在轴上安装像齿轮，皮带轮，飞轮，曲柄，链轮和其他动力传递零件。轴能够承受弯曲，拉伸，压缩或扭转载荷，这些力相结合时，人们期望找到静强度和疲劳强度作为设计的重要依据。因为单根轴 可以承受静压力，变应力和交变应力，所有的应力作用都是同时发生的。“轴”这个词包含着多种含义，例如心轴和主轴。心轴也是轴，既可以旋转也可 以静止的轴，但不承受扭转载荷。短的转动轴常常被称为主轴。当轴的弯曲或扭转变形必需被限制于很小的范围内时，其尺寸应根据变形来确 定，然后进行应力分析。因此，如若轴要做得有足够的刚度以致挠曲不太大，那么合 应力符合安全要求那是完全可能的。但决不意味着设计者要保证；它们是安全的，轴 几乎总是要进行计算的，知道它们是处在可以接受的允许的极限以内。因之，设计者 无论何时，动力传递零件，如齿轮或皮带轮都应该设置在靠近支持轴承附近。这就减 低了弯矩，因而减小变形和弯曲应力。虽然来自 M.H.G 方法在设计轴中难于应用，但它可能用来准确预示实际失效。这 样，它是一个检验已经设计好了的轴的或者发现具体轴在运转中发生损坏原因的好方 法。进而有着大量的关于设计的问题，其中由于别的考虑例如刚度考虑，尺寸已得到 较好的限制。设计者去查找关于圆角尺寸、热处理、表面光洁度和是否要进行喷丸处理等资料，那真正的唯一的需要是实现所要求的寿命和可靠性。由于他们的功能相似，将离合器和制动器一起处理。简化摩擦离合器或制动器的 动力学表达式中，各自以角速度 w1 和 w2 运动的两个转动惯量 I1 和 I2，在制动器情 况下其中之一可能是零，由于接上离合器或制动器而最终要导致同样的速度。因为两 个构件开始以不同速度运转而使打滑发生了，并且在作用过程中能量散失，结果导致 温升。在分析这些装置的性能时，我们应注意到作用力，传递的扭矩，散失的能量和 温升。所传递的扭矩关系到作用力，摩擦系数和离合器或制动器的几何状况。这是一 个静力学问题。这个问题将必须对每个几何机构形状分别进行研究。然而温升与能量 损失有关，研究温升可能与制动器或离合器的类型无关。因为几何形状的重要性是散 热表面。各种各样的离合器和制动器可作如下分类： 1．轮缘式内膨胀制冻块； 2．轮缘式外接触制动块； 3．条带式； 4．盘型或轴向式； 5．圆锥型；

6．混合式。分析摩擦离合器和制动器的各种形式都应用一般的同样的程序，下面的步骤是必 需的： 1．假定或确定摩擦表面上压力分布； 2．找出最大压力和任一点处压力之间的关系； 3．应用静平衡条件去找寻（a）作用力；（b）扭矩；(c)支反力。混合式离合器包括几个类型，例如强制接触离合器、超载释放保护离合器、超越 离合器、磁液离合器等等。强制接触离合器由一个变位杆和两个夹爪组成。各种强制接触离合器之间最大的 区别与夹爪的设计有关。为了在结合过程中给变换作用予较长时间周期，夹爪可以是 棘轮式的，螺旋型或齿型的。有时使用许多齿或夹爪。他们可能在圆周面上加工齿，以便他们以圆柱周向配合来结合或者在配合元件的端面上加工齿来结合。虽然强制离合器不像摩擦接触离合器用的那么广泛，但它们确实有很重要的运 用。离合器需要同步操作。有些装置例如线性驱动装置或电机操作螺杆驱动器必须运行到一定的限度然后 停顿下来。为着这些用途就需要超载释放保护离合器。这些离合器通常用弹簧加载，以使得在达到预定的力矩时释放。当到达超载点时听到的“喀嚓”声就被认定为是所 希望的信号声。超越离合器

或连轴器允许机器的被动构件“空转”或“超越”，因为主动驱动件 停顿了或者因为另一个动力源使被动构件增加了速度。这种离合器通常使用装在外套 筒和内轴件之间的滚子或滚珠。该内轴件，在它的周边加工了数个平面。驱动作用是 靠在套筒和平面之间契入的滚子来获得。因此该离合器与具有一定数量齿的棘轮棘爪 机构等效。磁液离合器或制动器相对来说是一个新的发展，它们具有两平行的磁极板。这些 磁极板之间有磁粉混合物润滑。电磁线圈被装入磁路中的某处。借助激励该线圈，磁 液混合物的剪切强度可被精确的控制。这样从充分滑移到完全锁住的任何状态都可以 获得。

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：毕业论文外文翻译

经济增速放缓对中国银行业的影响显现 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

中资银行净利润去年创下新高，似乎并没有受到中国这一世界第二大经济体经济增速放缓的影响。这是否意味着，银行业可以免受经济下行的影响呢？

未必。

银行业的反应往往有一定的滞后性。只有在一段时期后，中国宏观经济形势的影响才会在银行的营收中有所体现。

以不良贷款为例。在下降趋势持续了几年之后，不良贷款的比例终于开始上升，虽然涨幅不大。按资产总量计算，中国最大的银行中国工商银行(Industrial & Commercial Bank of China Ltd.)的不良贷款去年第四季度增加了人民币38.2亿元（约合6.06亿美元），中国第二大银行中国建设银行(China Construction Bank Corp.)的不良贷款增加了人民币62.7亿元。中国银行(Bank of China Ltd.)的不良贷款在第四季度增加了13.9亿元。（在中国，不良贷款指的是变成坏账的几率在30%以上的贷款。）

规模较小银行的不良贷款水平也在增长。中国最大的非国有银行中国民生银行(China

Minsheng Banking Corp.)2011年不良贷款增加了人民币2亿元。兴业银行(Industrial Bank Co.)的不良贷款去年增加了人民币9,900万元。

更能说明这一问题的是，中国银监会的数据显示，中国银行业的不良贷款比例在第四季度较第三季度上升了0.1个百分点，这是该比例过去六年来首次上升。

银监会没有给出原因，但是中资银行本周发布的年报提供了一些线索：房地产市场可能是罪魁祸首。

中国建设银行表示，在该银行的所有不良贷款中，与房地产业有关的不良贷款同比上涨了20%。民生银行说，其房地产融资业务的不良贷款比例为1.72%，大大超过了其0.63%的总体不良贷款比例。

两年来住房价格一直在承受压力，但直到现在我们才在银行的年报中看到了相关迹象。问题是，投资者是否看到了更多问题数据出现的可能性。

从2009年到2011年这三年里，中资银行共发放了25万亿元以人民币计价的贷款，其中约有40%的贷款流向了政府主导的基建项目和楼市。

今年的第二季度将是房地产贷款和地方政府借贷的还款高峰期。广发证券(GF Securities Co.)分析师沐华在最近的一份报告中说，由于经济减速，我们预计可能出现更多的不良贷款。

中国的金融服务公司诺亚财富投资管理有限公司(Noah Private Wealth Management, 简称：诺亚财富)说，共有1,172.5亿元的房地产信托产品将会在今年到期，高于去年的470.5亿元，这给房地产开发商的现金流造成了巨大压力。

分析人士说，除了房地产，地方政府借的贷款将为银行带来更大的挑战。据一些银行高管估计，中国10.7万亿元的政府贷款中，有三分之一将在今明两年到期。

标准普尔(Standard & Poor)的分析师廖强说，中国中央政府可能会给予地方政府债务一定的宽限，以防不良贷款激增。他说，尽管如此，房地产开发商以及供应过剩行业的制造企业仍会不时地面临由政策引发的再融资不确定性。

中国建设银行董事长王洪章周一在香港说，考虑到中国经济很可能继续保持稳定增长，他对该银行的资产质量持乐观态度。他说，不良贷款的水平是可控的。即使是比以往有所增加，总量还是很小，而且增长很可能也是暂时的。

第四篇：毕业论文外文翻译

外文翻译：

安全评估和风险管理方法建设

张军，张明元，袁勇波，周静

（中国土木与水利工程大学，大连理工，大连116085）

摘要： 改进后的LEC法是用于处理与期货大厦项目的安全评估的。经修订的评估项目L的危险方法隐藏的工作条件，存在由实验结果确定了不同价值体系之间的能源和人工能源，表明该方法的科学性和实用性，并能提高安全成本的经济效率。

关键词：建设危害，安全评价，安全管理

1建筑的危害和安全评估

建筑存在的危险性都和周围的建设用地有关系。这些条件不合理造成的勘查施工前和施工期间的经济活动不合理并会转移到危险性上。首先，它是认识到科学和危害之后而确定安全管理的必要，进行任何监测都有可能发生意外。

评估的目的是寻找出安全分析和预测危险的方法，而且其结果与现有工程或一个系统，都需要合理并可行。因此我们提出了从监督监测和抵御风险中得到的情况，以求意外事故有最低发生率，这是不同的方法之间的安全评估和正常的安全管理和监控。这样做的安全评估、分析、论证和可能的损失建筑工程有关的伤害和影响范围都最小。

安全文化是伴随人类的生产活动而产生的。但是，人类有意识地发展安全文化，还是近1 0余年的事，国际原子能机构在对1 9 8 6年发生的切尔诺贝利核泄漏事故调查分析的基础上，于1 9 9 1年编写的“7 5一工N 8 A G-4 "评。报告首次提出了“安全文化”的概念，并建立了一套核安全文化建设的思想和策略。

安全文化从核安全文化、航空航天安全文化等企业安全文化，拓宽到全民安全文化，由此发展到了由安全观念文化、安全行为文化、安全物质文化组成的全民安全文化的新时代。在该阶段，安全教育体系正在形成，儿童和，}，小学生的安全教育已经起步。大学和成人的专业化安全教育已初具规模，在有关政府机

构领导下的安全文化普及教育正蓬勃发展;安全科学作为独立的学科体系已经建立，安全科学形成了由安全科学技术基础学科、安全学、安全工程等构成的多学科体系;安全管理机构进一步健全，建立健全了一大批国际的、国家的、行业的、社会的、企业的安全管理机构;在法规、标准、安全制度方而，体现在而向全民的安全建设开始起步，而向行业的、企业的安全法规、标准、制度、操作规程等具有更强的针对性，在安全宣传方而，一个社会化的安全宣传网正在形成，出现了一些而向大众、宣传安全光荣、安全就是效益的作品，“安全第一，顶防为主”的安全哲学思想更加深入人心。

“安全文化是人类文化的部分，它涉及人类活动的各个领域，存在于社会生活的各个方而;它涉及自然科学和社会科学的诸学科，它为安全的世界观和方法论的形成提供乳育的胚胎，它既具有历史的继承性，又具有鲜明的时代感”。安全文化是灿烂的，华民族文化的组成部分，华民族在生存和繁衍，}，与世界其他民族一起创造并传播了安全文化。安全文化在我国的发展也经历了人类对安分与健康的台目追求、核安全文化出现、全民安全文化的兴起等二个阶段。2危险方法评估工作

考虑到人的危险在工作条件，格雷厄姆和吉尔伯特。楼金尼建议的频率和严重程度，以该评估环境和一些揭露应指环境变量作为独立设置的函数公式。根据他们的实际经验，根据不同情况独立变量的值，给出了三被标记的对象，然后在危害水平也分为公式后的危险值来计算。这种方法容易识别。

D=LEC

其中，D指该商标，L是指事故的发生概率，E和C是指人类正暴露的频率和在环境意味着损失。

3管理建设的危害

建造业是高风险行业，需要管理并改善其意外总数的发生。政府提出安全建设模式位“统一的模式，法律监督机构负责企业所有安全监管，部分群众以及整个社会参与监督”。作者假设如下：

（1）加强安全监察，建设，以确保施工安全的措施费组成竞争费和特殊项目费用;建设行政主管部门应加强项目前的审计。

（2）加强并完善组织建设施工安全监管，成立一个监管组织，其的特点是依法执行监管任务。

（3）编制依据不同专业的职业经理人的安全的安全生产监管部根据建筑由大小的地盘遵守《组织对构建企业安全生产和职业经理人准备》。

（4）发展项目和危害安全风险评估，登记项目，消除构建社会安全危害的可能影响。

（5）建立和落实，检查系统的支架固定和拆卸起重机械，成型板，建立和落实制度，消除危害的技术，设备和材料，建立和实施项目系统研究项目的施工安全。

（6）监测信息系统的致命危害工地使用是高级电力监控。

（7）开展风险规避。风险规避是一个有用的和共同的风险管理策略。当认识到严重后果的隐患和风险因素，但没有可用的措施之前，建设，施工计划可能改变或放弃为避免风险。

（8）建筑企业要建立和完善安全体系建设的长期性，管理和设备应达到 降低风险损失之和（参考标准：标准JGJ59 一 1999年）。

（9）发挥媒体的咨询作用，进行系统的安全性评估、设计、安全监测、认证和考试，以及意外伤害保险赔偿。

（10）建立工会公关，处理紧急项目。

4结论

本文主要内容是考察了管理层在判断建筑危害中应用的安全性评估方法。以及建设项目危险评价工作的执行情况，我们已确保了致命的危险事故发生率为最低。根据经验，可纳入危险管理系统的危险值为：低于160时的危险，否则，它会被认为是不可承受的危险事故。应该充分应用现代化的信息技术来建立和完善

一道预防和控制系统来检测意外事故。以期待应用技术来预防更多的意外事故发生。

第五篇：毕业论文外文翻译

国际服务贸易：对进口商和出口商的详细描述

霍尔格·布仁里奇基娅拉·克里斯库勒

摘要：本文提供了一组从事国际服务贸易企业的一些新颖的特殊案例，采用的独特数据来自于进出口企业的世界第二大服务出口国——英国。数据显示在英国只有一小部分的公司从事国际服务贸易，并且行业分布广泛，无论从公司规模、生产力还是公司其他特点来看，该国服务贸易商与其他贸易商的区别还是很大的。本文同时也提供了详细的数据证明该国服务进出口商贸易模式，比如市场供应量、每个市场的出口和进口货值以及在单个市场销售总量中所占的份额。本文将运用现有的服务和货物贸易理论来对上述现象进行充分的解释。研究结果表明，企业间的异质性是服务贸易的主要特征。此外，在企业层面上来讲，服务贸易与货物贸易还是有许多共同点，并由此得出结论：现存的异质性货物贸易公司模型同样也能够作为很好的出发点来解释相关的服务贸易。

关键字：国际服务贸易，企业层次解析

1、引言

服务贸易一直是国际贸易发展过程中增长最快的部分，20世纪90年代初以 来，服务贸易以将近10%的年增长率快速增长，在2006年服务贸易的总出口量达到了2800亿美元（根据世界贸易组织，2008年）。在同一时期，服务的内容也迅速转向以高新技术密集型为代表的新类别。比如引起激烈讨论的服务外包等商业服务类。一般来说，鉴于发达经济体服务行业的未来发展趋势以及重要性，服务贸易自由化在过去以及现在都被作为贸易谈判的重要环节并不会让人们感到奇怪。

尽管如此，我们还是发现很少的公司从事服务贸易行业。这与货物贸易的相关研究形成了鲜明的对比，货物贸易的相关研究为出口国提供了很多鲜明的实例，最近研究表明，货物贸易的相关研究同样也能为进口企业提供有效的实例。这些企业都是大型的，生产力很高的企业，企业使用了更多的资本密集型的生产工序，还聘请了高技能劳动力（详见贝尔纳，杰森，1995,1999；贝尔纳等，2007；瓦格内尔，2007；格林纳威，科内尔勒，2007）。此文献的数据也表明，部分企业的货物出口额常常很低。即使在出口商中，大部分的公司只会在很少的几个国外市场进行贸易，并把自己的主要销售目标放在了国内市场（贝尔纳，杰森，1999；伊顿等，2004；贝尔纳等，2009）。这些研究同样激发了更多学者推出更多的理论文献，并通过许多尝试将这些事例融入不同的理论框架（例如：梅利兹，2003；贝尔纳等，2003,2009；伊顿等，2008）。

本文通过对2000年——2005年在英国服务贸易进出口的两个独特的企业级数据的分析，我们首次为从事服务贸易的公司提出了一套可比的程式化事例。这些数据的第一个受访者资料（ARD）包含了企业级服务进出口贸易的价值信息以及相关附加变量的取值范围，同时，这也做为英国的民营企业的样本象征。这能使我们能够轻易区分服务进出口公司以及不从事服务贸易的公司，也能让我们能够分析这些群体之间的差异性。我们还将ARD与ITIS（国家贸易服务查询）进行结合。因为ITIS能够提供更多详细的服务贸易公司信息。比如：与该国进行贸易的国家以及该国服务进出口贸易模式。

我们将使用这两套数据以及一些其他附加的原始数据来描绘出英国服务进

出口的贸易特点和贸易模式。我们的首要目标是改进现有的关于服务贸易的相关理论文献。以下详细提及描述的文献，目前要么完全倚靠完全竞争或者垄断竞争理论框架要么完全依靠具有代表性的公司。研究表明，这种抽象略看企业异质性的显著水平，使得我们难以了解国际服务贸易的一些重要方面。本文的第一部分主要从更加详细的方面分析了企业的异质性，同时还提供了提套经验规律，可以使得未来具有异质性的服务贸易的公司模型能够复制。我们主要将以两个步骤来使得上述企业级货物贸易在经验规律文献下能够慢慢地有序发展。

第一步是使用ARD来识别英国的公司里的服务贸易进出口商，然后将这些服务贸易商与不从事服务贸易的企业进行比较。在第二个步骤中，我们会将ARD以及ITIS的相关数据进行结合分析，以便不仅能够了解进出口状况，也能够对从事服务贸易的企业的贸易模式提供更多的细节。

为了今后的理论工作提供投入，我们对于研究结果的政策影响也十分感兴趣。例如：我们的研究结果有助于我们了解过去和未来的服务贸易实施自由化的后果。类似货物贸易自由化，服务贸易自由化可能导致纯粹的国内企业的市场份额，以及从事服务贸易的企业变化。研究发现，进口商和出口商的许多公司特点（生产力，技术密集度等）与国内企业不同，本文建议在服务贸易自由化之后，增加总的生产率和技能的需求将有重要的意义。

2、文献综述

关于服务贸易的理论文献中占主导地位的主题是分从贸易不同的程度来看，析服务贸易与货物贸易有哪些不同，以及如何影响先前的货物贸易理论成果。比如：希尔（1977）认为，大多数服务的主要特点是要求联合生产必须同时消费和生产。因为服务不能储存，对于一项交易来说，生产者和消费者都必须是现行的，服务交易必须发生在同一时间，可能的话应该发生在同一地点。迪尔朵夫（1985年）和梅尔文（1989）认为法律服务贸易的比较优势功能可能失效，或至少需要重新解释。米尔扎和尼科莱蒂（2004）指出，进行联合生产时取得的从出口国和进口国的投入通常需要服务贸易。

在引力方程框架的基础上，过去十年的服务贸易的工作经验同样也增加了。这些货物贸易文献论文缺乏详细的微观层面的数据，也没有分析国家或行业服务贸易的总体水平数据（如弗氏和文候得，木村和李。2002年，2006;海德，2009）这些研究结果是与货物贸易的相关研究是类似。例如海德等（2009）和木村和李（2006）估计可比较的货物和服务贸易细则以及找到类似的弹性估计。海德，迈耶和里斯还表明，其他变量在货物贸易的重力回归被发现，比如共同的语言或共享的殖民地起源，都会相应地增加商品和服务贸易。

3、定义和数据描述

在本节中，我们描述的企业级数据服务进口和出口，并使用额外的变量。我们首先解释在本文中国际服务贸易的定义，然后说明我们的主要数据来源，以及它们是如何与我们分析的目的相结合的。附录A包含更多细节上的数据。

3.1 国际服务贸易的定义

在这篇论文中，服务贸易的定义是根据国际货币基金组织（IMF）的国际收支平衡手册的基本定义（第5版），在英国收支平衡统计的平衡的基础上被编译（见国际货币基金组织，1993）。因此，国际服务贸易是指一个经济体系的居民和非居民之间的服务交易。

3.2 数据来源

3.2.1 受访者资料库

我们的第一个主数据源是受访者资料库（ARD），这是基于英国国家统计局的一项强制性对英国企业进行的调查，并且英国的受访者资料库也是相当于美国的纵向受访者数据库的。ARD是基于英国每年超过40,000私营部门的公司的一个分层抽样，小型企业和大型企业的全面随机抽样（根据今年的那些员工超过100或250）。ARD的包含了其他变量，比如：就业信息，投资，中间投入，增加值，总产出，行业隶属关系，企业位置和外国所有权.本文还包括对跨国公司的地位从外商直接投资的注册信息，（见克里斯库勒和马丁，2009）。

3.2.2 国际贸易的咨询服务

第二大信息的主要来源是国际贸易查询服务（ITIS），ITIS也是由国家统计局进行的。它收集的国际交易数据是来自于英国本土的私营部门公司的服务和服务帐户（统计局，2007），同样也是英国国际收支的平衡贸易的主要投入。ITIS调查的公司一般都拥有10个或更多的员工。此项调查是法定的，是在上季度和上的基础上进行。我们充分结合了这两种查询方式。自2001年以来，我们每年已经采样了已超过20,000公司（2001年之前为10,000）。

3.2.3 第三代客户综合系统创新调查

我们运用了第三代客户综合系统创新调查（CIS3），其中包括1998-2000年期间所得到企业的出口货物，高技能，并被当做衡量毕业生在劳动力中所占的比例信息的数据。这是唯一可用的统计局的数据集，其中包含对这些变量的直接信息。类似于ARD的服务贸易，CIS3提供了一个企业的出口状态的和出口货物的总价值的信息，但不是具体的产品出口或出口目的地。CIS3是基于分层随机抽样，来调查约20000个左右的制造业和服务业的英国企业。这项调查包含货物在1998年和2000年出口的信息，以及2000年的技能信息。

3.3 样本组合和描述性统计

在本文的其它部分，我们将使用这三种调查的不同组合。所有这三个数据集包含常见的公司标识，因而很容易合并。我们首先使用ARD的数据对服务贸易商的特点和非贸易商进行比较（4.1节）。在4.1节中，贸易商技能服务以及读物和商品出口商的比较结果是基于合并后的ARD数据以及2000年的CIS3数据。通过结合该的ARD和CIS3数据，我们获得了出口服务商样本所包含的信息（来源于ARD），货物出口和企业技能强度（来源于CIS3），以及其他企业级的变量，比如就业和生产力的（来源于ARD）。

4、服务贸易商的特殊事例

接下来，本文将提出服务的出口商和进口商的特殊事例。我们首先关注的服务贸易商和非服务贸易商的比较（4.1节）。然后，我们描述了现有的服务商的贸易模式并提出了解释在企业级和总服务贸易的变化和密集广泛的利率的重要性（4.2节）。最后，我们在每一个部分都做了小结，以便未来研究可能的讨论和经济政策影响。

因此，货物贸易的异构的企业模型似乎也成为了提供了解释服务贸易的微观模式的一个很好的开始点。这也许是不奇怪，因为我们的研究结果和上述讨论在货物贸易文献相比较的事实之间的存在相似性。然而，我们还注意到一个服务贸易模式的一些有趣的特殊性，比如服务商似乎主要是沿着较高的利润率扩大出口和进口的事实。再次，我们认为，这些分歧不要求对货物贸易的现有模式的重大

修改，虽然他们可能意味在关键的参数值中重要的定量差异，比如市场准入或变量的贸易成本。

5、结论

在本文中，本文使用了英国的出口和进口在2000-2005年期间独特的企业级数据，为从事国际服务贸易的企业提供了一套的特殊事例。从这些事例中出现的两个主要结果一个是在企业级的服务贸易中的异质性很强，有时与货物贸易文献中找到的数据模式有惊人的相似。另一个就是使企业异质性纳入现有模式的服务。这对于获取服务出口和进口的关键方面是十分有必要的。货物贸易的现有模式应该是这样做的一个极好的出发点，即使有可能使用一些必要的修改来解释在整篇论文所强调货物和服务贸易之间的差异。