外文翻译
英文原文
Belt Conveying Systems Development of driving system
Among the methods of material conveying employed，belt conveyors play
a very important part in the reliable carrying of material over long
distances at competitive cost．Conveyor systems have become larger and more complex and drive systems have also been going through a process of evolution and will continue to do so．Nowadays，bigger belts require more power and have brought the need for larger individual drives as well as multiple drives such as 3 drives of 750 kW for one belt(this is the case for the conveyor drives in Chengzhuang Mine)．The ability to control drive acceleration torque is critical to belt conveyors’performance．An efficient drive system should be able to provide smooth，soft starts while maintaining belt tensions within the specified safe limits．For load sharing on multiple drives．torque and speed control are also important considerations in the drive system’s design.
Due to the advances in conveyor drive control technology，at present many more reliable．Cost-effective and performance-driven conveyor drive systems
covering a wide range of power are available for customers’ choices[1].
1 Analysis on conveyor drive technologies
1．1 Direct drives
Full-voltage starters．With a full-voltage starter design，the conveyor head shaft is direct-coupled to the motor through the gear drive．Direct full-voltage starters are adequate for relatively low-power, simple-profile conveyors．With direct fu11-voltage starters．no control is provided for various conveyor loads and．depending on the ratio between fu11-and no-1oad power requirements，empty starting times can be three or four times faster than full load．The maintenance-free starting system is simple，low-cost and very reliable．However, they cannot control starting torque and maximum stall torque；therefore．they are
limited to the low-power, simple-profile conveyor belt drives．
Reduced-voltage starters．As conveyor power requirements increase，controlling the applied motor torque during the acceleration period becomes increasingly important．Because motor torque 1s a function of voltage，motor voltage must be controlled．This can be achieved through reduced-voltage starters by employing a silicon controlled rectifier(SCR)．A common starting method with SCR reduced-voltage starters is to apply low voltage initially to take up conveyor belt slack．and then to apply a timed linear ramp up to full voltage and belt speed．However, this starting method will not produce constant conveyor belt acceleration．When acceleration is complete．the SCRs,which control the applied voltage to the electric motor． are locked in full conduction, providing fu11-line voltage to the motor．Motors with higher torque and pull—up torque，can provide better starting torque when combined with the SCR starters, which are available in sizes up to 750 KW．
Wound rotor induction motors．Wound rotor induction motors are connected directly to the drive system reducer and are a modified configuration of a standard AC induction motor．By inserting resistance in series with the motor’s rotor windings．the modified motor control system controls motor torque．For conveyor starting，resistance is placed in series with the rotor for low initial torque．As the conveyor accelerates，the resistance is reduced slowly to maintain a constant acceleration torque．On multiple-drive systems．an external slip resistor may be left in series with the rotor windings to aid in load sharing．The motor systems have a relatively simple design．However, the control systems for these can be highly complex，because they are based on computer control of the resistance switching．Today，the majority of control systems are custom designed to meet a conveyor system’s particular specifications．Wound rotor motors are appropriate for systems requiring more than 400 kW ．
DC motor．DC motors．available from a fraction of thousands of kW ，are designed to deliver constant torque below base speed and constant kW above base speed to the maximum allowable revolutions per minute(r/min)．with the majority of conveyor drives, a DC shunt wound motor is used．Wherein the motor’s rotating armature is
connected externally．The most common technology for controlling DC drives is a SCR device． which allows for continual variable-speed operation．The DC drive system is mechanically simple, but can include complex custom-designed electronics to monitor and control the complete system．This system option is expensive in comparison to other soft-start systems．but it is a reliable, cost-effective drive in applications in which torque,1oad sharing and variable speed are primary considerations．DC motors generally are used with higher-power conveyors，including complex profile conveyors with multiple-drive systems，booster tripper systems needing belt tension control and conveyors requiring a wide variable-speed range．1．2 Hydrokinetic coupling
Hydrokinetic couplings，commonly referred to as fluid couplings．are composed of three basic elements; the driven impeller, which acts as a centrifugal pump；the driving hydraulic turbine known as the runner and a casing that encloses the two power components．Hydraulic fluid is pumped from the driven impeller to the driving runner, producing torque at the driven shaft．Because circulating hydraulic fluid produces the torque and speed，no mechanical connection is required between the driving and driven shafts．The power produced by this coupling is based on the circulated fluid’s amount and density and the torque in proportion to input speed．Because the pumping action within the fluid coupling depends on centrifugal forces．the output speed is less than the input speed．Referred to as slip．this normally is between l% and 3%．Basic hydrokinetic couplings are available in configurations from fractional to several thousand kW ．
Fixed-fill fluid couplings．Fixed-fill fluid couplings are the most commonly used soft-start devices for conveyors with simpler belt profiles and limited convex/concave sections．They are relatively
simple,1ow-cost,reliable,maintenance free devices that provide excellent soft starting results to the majority of belt conveyors in use today．Variable-fill drain couplings．Drainable-fluid couplings work on the same principle as fixed-fill couplings．The coupling’s impellers are mounted on the AC motor and the runners on the driven reducer high-speed shaft．Housing mounted to the drive base encloses the working circuit．The coupling’s rotating casing contains
bleed-off orifices that continually allow fluid to exit the working circuit into a separate hydraulic reservoir．Oil from the reservoir is pumped through a heat exchanger to a solenoid-operated hydraulic valve that controls the filling of the fluid coupling．To control the starting torque of a single-drive conveyor system，the AC motor current must be monitored to provide feedback to the solenoid control valve．Variable fill drain couplings are used in medium to high-kW conveyor systems and are available in sizes up to thousands of kW ．The drives can be mechanically complex and depending on the control parameters．the system can be electronically intricate．The drive system cost is medium to high, depending upon size specified．Hydrokinetic scoop control drive．The scoop control fluid coupling consists of the three standard fluid coupling components：a driven impeller, a driving runner and a casing that encloses the working circuit．The casing is fitted with fixed orifices that bleed a predetermined amount of fluid into a reservoir．When the scoop tube is fully extended into the reservoir, the coupling is l00 percent filled．The scoop tube, extending outside the fluid coupling，is positioned using an electric actuator to engage the tube from the fully retracted to the fully engaged position．This control provides reasonably smooth acceleration rates．to but the computer-based control system is very complex．Scoop control couplings are applied on conveyors requiring single or multiple drives from l50 kW to 750 kW.
1．3 Variable-frequency control(VFC)
Variable frequency control is also one of the direct drive methods．The emphasizing discussion about it here is because that it has so unique characteristic and so good performance compared with other driving methods for belt conveyor． VFC devices Provide variable frequency and voltage to the induction motor, resulting in an excellent starting torque and acceleration rate for belt conveyor drives．VFC drives．available from fractional to several thousand(kW ), are electronic controllers that rectify AC line power to DC and，through an inverter, convert DC back to AC with frequency and voltage contro1．VFC drives adopt vector control or direct torque control(DTC)technology，and can adopt different operating speeds according to different loads．VFC drives can make starting or stalling
according to any given S-curves．realizing the automatic track for starting or stalling curves．VFC drives provide excellent speed and torque control for starting conveyor belts．and can also be designed to provide load sharing for multiple drives．easily VFC controllers are frequently installed on lower-powered conveyor drives，but when used at the range of medium-high voltage in the past．the structure of VFC controllers becomes very complicated due to the limitation of voltage rating of power semiconductor devices，the combination of medium-high voltage drives and variable speed is often solved with low-voltage inverters using step-up transformer at the output，or with multiple low-voltage inverters connected in series．Three-level voltage-fed PWM converter systems are recently showing increasing popularity for multi-megawatt industrial drive applications because of easy voltage sharing between the series devices and improved harmonic quality at the output compared to two-level converter systems With simple series connection of devices．This kind of VFC system with three 750 kW /2．3kV inverters has been successfully installed in ChengZhuang Mine for one 2．7-km long belt conveyor driving system in following the principle of three-level inverter will be discussed in detail．
2 Neutral point clamped(NPC)three-level inverter using IGBTs
Three-level voltage-fed inverters have recently become more and more popular for higher power drive applications because of their easy voltage sharing features．1ower dv/dt per switching for each of the devices，and superior harmonic quality at the output．The availability of HV-IGBTs has led to the design of a new range of medium-high voltage inverter using three-level NPC topology．This kind of inverter can realize a whole range with a voltage rating from 2．3 kV to 4．1 6 kV Series connection of HV-IGBT modules is used in the 3．3 kV and 4．1 6 kV devices．The 2．3 kV inverters need only one HV-IGBT per switch[2,3].
2．1 Power section
To meet the demands for medium voltage applications．a three-level neutral point clamped inverter realizes the power section．In comparison to a two-level inverter．the NPC inverter offers the benefit that three voltage levels can be supplied to the output terminals，so for the same output current quality，only
1/4 of the switching frequency is necessary．Moreover the voltage ratings of the switches in NPC inverter topology will be reduced to 1/2．and the additional transient voltage stress on the motor can also be reduced to 1/2 compared to that of a two-level inverter．
The switching states of a three-level inverter are summarized in Table 1．U．V and W denote each of the three phases respectively；P N and O are the dc bus points．The phase U，for example，is in state P(positive bus voltage)when the
switches S
1u and S
2u
are closed，whereas it is in state N (negative bus voltage)
when the switches S
3u and S
4u
are closed．At neutral point clamping，the phase is
in O state when either S
2u or S
3u
conducts depending on positive or negative phase
current polarity，respectively．For neutral point voltage balancing，the average current injected at O should be zero．
2．2 Line side converter
For standard applications．a l2-pulse diode rectifier feeds the divided DC-link capacitor．This topology introduces low harmonics on the line side．For even higher requirements a 24-pulse diode rectifier can be used as an input converter．For more advanced applications where regeneration capability is necessary, an active front．end converter can replace the diode rectifier, using the same structure as the inverter．
2．3 Inverter control
Motor Contro1．Motor control of induction machines is realized by using a rotor flux．oriented vector controller．
Fig．2 shows the block diagram of indirect vector controlled drive that incorporates both constant torque and high speed field-weakening regions where the PW M modulator was used．In this figure，the command flux is generated as function of speed．The feedback speed is added with the feed forward slip command signal . the resulting frequency signal is integrated and then the unit vector
signals(cos and sin )are generated．The vector rotator generates the voltage and angle commands for the PW M as shown．
PWM Modulator．The demanded voltage vector is generated using an elaborate
PWM modulator．The modulator extends the concepts of space-vector modulation to the three-level inverter．The operation can be explained by starting from a regularly sampled sine-triangle comparison from two-level inverter．Instead of using one set of reference waveforms and one triangle defining the switching
and frequency， the three-level modulator uses two sets of reference waveforms U
r1
and just one triangle．Thus, each switching transition is used in an optimal U
r2
way so that several objectives are reached at the same time．
Very low harmonics are generated．The switching frequency is low and thus switching losses are minimized．As in a two-level inverter, a zero-sequence component can be added to each set of reference waveform s in order to maximize the fundamental voltage component．As an additional degree of freedom，the position of the reference waveform s within the triangle can be changed．This can be used for current balance in the two halves of the DC-1ink．
3 Testing results
After Successful installation of three 750 kW /2．3 kV three-level inverters for one 2．7 km long belt conveyor driving system in Chengzhuang Mine．The performance of the whole VFC system was tested．Fig．3 is taken from the test，which shows the excellent characteristic of the belt conveyor driving system with VFC controller．
Fig．3 includes four curves．The curve 1 shows the belt tension．From the curve it can be find that the fluctuation range of the belt tension is very smal1．Curve 2 and curve 3 indicate current and torque separately．Curve 4 shows the velocity of the controlled belt．The belt velocity have the“s”shape characteristic．A1l the results of the test show a very satisfied characteristic for belt driving system．
4 Conclusions
Advances in conveyor drive control technology in recent years have resulted in many more reliable．Cost-effective and performance-driven conveyor drive system choices for users．Among these choices，the Variable frequency control (VFC) method shows promising use in the future for long distance belt conveyor drives due to its excellent performances．The NPC three-level inverter using high voltage IGBTs
make the Variable frequency control in medium voltage applications become much more simple because the inverter itself can provide the medium voltage needed at the motor terminals，thus eliminating the step-up transformer in most applications in the past．
The testing results taken from the VFC control system with NPC three．1evel inverters used in a 2．7 km long belt conveyor drives in Chengzhuang Mine indicates that the performance of NPC three-level inverter using HV-IGBTs together with the control strategy of rotor field-oriented vector control for induction motor drive is excellent for belt conveyor driving system．
中文译文：
带式输送机及其牵引系统
在运送大量的物料时，带式输送机在长距离的运输中起到了非常重要的竞争作用。输送系统将会变得更大、更复杂，而驱动系统也已经历了一个演变过程，并将继续这样下去。如今，较大的输送带和多驱动系统需要更大的功率,比如3驱动系统需要给输送带750KW (成庄煤矿输送机驱动系统的要求)。控制驱动力和加速度扭矩是输送机的关键。一个高效的驱动系统应该能顺利的运行,同时保持输送带张紧力在指定的安全极限负荷内。为了负载分配在多个驱动上，扭矩和速度控制在驱动系统的设计中也是很重要的因素。由于输送机驱动系统控制技术的进步,目前更多可靠的低成本和高效驱动的驱动系统可供顾客选择[1]。
1 带式输送机驱动
1.1 带式输送机驱动方式
全电压启动在全电压启动设计中，带式输送机驱动轴通过齿轮传动直接连接到电机。直接全压驱动没有为变化的传送负载提供任何控制,根据满载和空载功率需求的比率，空载启动时比满载可能快3～4倍。此种方式的优点是:免维护,启动系统简单，低成本，可靠性高。但是，不能控制启动扭矩和最大停止扭矩。因此，这种方式只用于低功率,结构简单的传送驱动中。
降压启动随着传送驱动功率的增加,在加速期间控制使用的电机扭矩变得越来越重要。由于电机扭矩是电压的函数,电机电压必须得到控制，一般用可控硅整流器(SCR) 构成的降压启动装置，先施加低电压拉紧输送带,然后线性的增加供电电压直到全电压和最大带速。但是，这种启动方式不会产生稳定的加速度，当加速完成时,控制电机电压的SCR 锁定在全导通，为电机提供全压。此种控制方式功率可达到750kW。
绕线转子感应电机绕线转子感应电机直接连接到驱动系统减速机上,通过在电机转子绕组中串联电阻控制电机转矩。在传送装置启动时,把电阻串联进转子产生较低的转矩，当传送带加速时，电阻逐渐减少保持稳定增加转矩。在多驱动系统中，一个外加的滑差电阻可能将总是串联在转子绕组回路中以帮助均分负载。该方式的电机系统设计相对简单，但控制系统可能很复杂，因为它们是基于计算机控制的电阻切换。当今，控制系统的大多数是定制设计来满足传送系统的特殊规格。绕线转子电机适合于需要400kW以上的系统。
直流(DC)电机大多数传送驱动使用DC 并励电机，电机的电枢在外部连接。控制DC 驱动技术一般应用SCR装置，它允许连续的变速操作。DC 驱动系统在机械上是简单的,但设计的电子电路，监测和控制整个系统，相比于其他软启动系统的选择是昂贵的，但在转矩、负载均分和变速为主要考虑的场合,它又是一个可靠的，节约成本的方式。DC 电机一般使用在功率较大的输送装置上,包括需要输送带张力控制的多驱动系统和需要宽变速范围的输送装置上。
1.2 液力偶合器
流体动力偶合器通常被称为液力偶合器，由三个基本单元组成：充当离心泵的叶轮,推进水压的涡轮和装进两个动力部件的外壳。流体从叶轮到涡轮，在从动轴产生扭矩。由于循环流体产生扭矩和速度，在驱动轴和从动轴之间不需要任何机械连接。这种连接产生的动力决定于液力偶合器的充液量，扭矩正比于输入速度。因在流体偶合中输出速度小于输入速度,其间的差值称为滑差,一般为1 %～3 %。传递功率可达几千千瓦。
固定充液液力偶合器固定充液液力偶合器是在结构较简单和仅具有有限的弯曲
部分的输送装置中最常用的软启动装置，其结构相对比较简单，成本又低，对现在使用的大多数输送机能提供优良的软启动效果。
可变充液液力偶合器也称为限矩型液力偶合器。偶合器的叶轮装在AC 电机上,涡轮装在从动减速器高速轴上，包含操作部件的轴箱安装在驱动基座。偶合器的旋转外壳有溢出口,允许液体不断地从工作腔中流出进入一个分离的辅助腔，油从辅助腔通过一个热交换器泵到控制偶合器充液量的电磁阀。为了控制单机传动系统的启动转矩,必须监测AC 电机电流,给电磁阀的控制提供反馈。可变充液液力偶合器可使用在中大功率输送系统中，功率可达到数千千瓦。这种驱动无论在机械,或在电气上都是很复杂的，其驱动系统成本中等。
勺管控制液力偶合器也称为调速型液力偶合器。此种液力偶合器同样由三个标准的液力偶合单元构成，即叶轮、涡轮和一个包含工作环路的外壳。此种液力偶合器需要在工作腔以外设置导管(也称勺管) 和导管腔，依靠调节装置改变勺管开度(勺管顶端与旋转外壳间距) 人为的改变工作腔的充液量,从而实现对输出转速的调节。这种控制提供了合理的平滑加速度，但其计算机控制系统很复杂。勺管控制液力偶合器可以应用在单机或多机驱动系统，功率范围为150kW～750kW。
1．3 变频控制(VFC)
变频控制也是一种直接驱动方式，它具有非常独特的高性能。VFC 装置为感应电机提供变化的频率和电压,产生优良的启动转矩和加速度。VFC设备是一个电力电子控制器,首先
把AC 整流成DC ，然后利用逆变器，再将DC 转换成频率、电压可控的AC。VFC 驱动采用矢量控制或直接转矩控制(DTC) 技术，能根据不同的负载采用不同的运行速度。VFC 驱动能根据给定的S 曲线启动或停车，实现自动跟踪启动或停车曲线。VFC 驱动为传送带启动提供了优良的速度和转矩控制，也能为多机驱动系统提供负载均分。VFC 控制器可以容易地装在小功率输送机驱动上。过去在中高电压使用时，VFC 设备的结构由于受电力半导体器件的电压额定值限制而变得很复杂，中高电压的变速传动常常使用低压逆变器，然后在输出端使用升压变压器，或使用多个低压逆变器串联来解决。与简单的器件串联连接的两电平逆变器系统比较，由于串联器件之间容易均压以及输出端可以有更好的谐波特性，三电平电压型PWM 逆
变器系统在数兆瓦工业传动中近年来获得了越来越多的应用。由三台750kW/ 2. 3kV 的这种逆变器构成的VFC 系统已经成功安装在成庄煤矿长2. 7km的带式输送机驱动系统中。
2 使用IGBT的中性点箝位三电平逆变器
由于串联器件电压均分容易,器件每次开关的d v/ d t 低以及输出端出色的谐波品质，三电平电压型逆变器在大功率传动应用中变得越来越流行。高压IGBT(HV-IGBT) 的出现使得应用三电平中性点箝位原理的中高压逆变器设计有了更大的应用范围。这种逆变器目前可以实现从2. 3kV到4. 16kV全范围的应用。HV-IGBT 模块串联可使用在3. 3kV和4.
16kV的设备。2. 3kV逆变器每个开关只需要一个HV-IGBT[2,3]。
2．1 主功率逆变电路
主功率逆变电路用三电平中点箝位电压型逆变器实现,可以满足中高压交流传动应用
的需要。与两电平电压型逆变器相比，三电平中点箝位电压型逆变器提供三个电压级别给输出端，对于同样的输出电流品质，开关频率可降低到原来的1/ 4，开关器件的电压额定值可减小到原来的1/ 2 ，附加到电机上的额外的瞬态电压应力也可能减少到原来的1/ 2 。
三电平中点箝位电压型逆变器的开关状态可归纳于表1 ，U ，V 和W 分别表示三相，P，N 和O 是直流母线上的三个点。例如，当开关S1U和S2U闭合时，U 相处于状态P(正母线电压) ，反之，当开关S3U和S4U闭合时，U 相处于状态N (负母线电压) 。在中性点箝位时,该相在O 状态，这时根据相电流极性的正负,或者是S2U导通或者是S3U导通。为了保证中性点电压平衡，在O 点被注入的平均电流应该是零。
2.2 输入端变流器
为通常使用12 脉冲二极管整流器给直流环节电容器充电,在输入端引入的谐波是很小的。若对输入谐波有更高的要求，可以使用24 脉冲二极管整流器作为输入变流器。对于需要有再生能力的更高级应用，可以用一个有源输入变流器取代二极管整流器，这时输入
整流器与输出逆变器为同一结构。
2.3 逆变器控制
电机控制感应电机的控制可以使用转子磁场定向矢量控制器实现,通过使用PWM 调制器完成了恒转矩区和高速弱磁区的控制。图2 为间接矢量控制框图。图中指令磁通Ψr 是速度的函数,反馈速度和前馈滑差控制信号ωsl相加。对相加结果的频率信号积分，然后产生单位矢量(cosθe 和sinθe ) ，最后通过矢量旋转器产生电压角控制PWM 调制器。
PWM调制器该调制器实际上是把空间矢量调制概念扩展到三电平逆变器。其基本原理是三电平PWM 调制器使用两个参考波U r1和U r2，但只使用一个三角波。它以一种优化方式确定每一次开关时刻。
产生的谐波尽可能的小，使用尽可能低的开关频率以最小化开关损耗；可将零序成分加到每一个参考波里以便最大化基波电压。作为一个附加的自由度,参考波与三角波的相对位置可改变，这可以用于直流环节中点的电流平衡。
3 测试结果
三个750kW/ 2. 3kV 三电平逆变器在成庄煤矿2. 7km 长带式输送机驱动系统成功安装之后,对整个变频传动系统(VFC) 的性能进行了测试,测试结果显示出使用VFC 控制系统的带式输送机的优良特性。图3为测试结果波形。由图看出,曲线1 显示受控带速,带速呈S 形曲线形状,曲线2 、3 分别表示电流和扭矩,曲线4 显示带张力。从图中可以发现,带张力的波动范围很小，所有检测结果显示出带式输送机驱动系统令人满意的特性。
4结论
近年来输送机驱动控制技术的进步已更为可靠，符合低成本效益和高效驱动的驱动系统为用户提供了选择。在这些选择中，可变频率控制(VFC)的方法显现出在将来长距离输送中带式输送机扮演了重要的角色。使用高压IGBT 的中点嵌位三电平逆变器本身可以提供电机终端所需的供电中高压,使变频控制的应用更为简单。通过成庄煤矿2. 7km长带式输送机中采用的中点嵌位三电平逆变器变频调速(VFC)控制系统的测试结果表明,采用
HV-IGBT 的中点嵌位三电平逆变器以及使用转子磁场矢量控制策略的感应电机变频传动,使带式输送机驱动系统具有非常优秀的性能,显示出良好的应用前景。
中英文资料对照外文翻译 机械设计 摘要： 机器由机械和其他元件组成的用来转换和传输能量的装置。比如：发动机、涡轮机、车、起重机、印刷机、洗衣机和摄影机。许多机械方面设计的原则和方法也同样适用于非机械方面。术语中的“构造设计”的含义比“机械设计”更加广泛，构造设计包括机械设计。在进行运动分析和结构设计时要把产品的维护和外形也考虑在机械设计中。在机械工程领域中，以及其它工程领域，都需要机械设备，比如：开关、凸轮、阀门、船舶以及搅拌机等。 关键词：设计流程设计规则机械设计 设计流程 设计开始之前就要想到机器的实用性，现有的机器需要在耐用性、效率、重量、速度，或者成本上得到改善。新的机器必需能够完全或部分代替以前人的功能，比如计算、装配、维修。 在设计的初级阶段，应该充分发挥设计人员的创意，不要受到任何约束。即使有一些不切实际的想法，也可以在设计的早期，即在绘制图纸之前被改正掉。只有这样，才不致于阻断创新的思路。通常,必须提出几套设计方案,然后进行比较。很有可能在这个计划最后指定使用某些不在计划方案内的一些想法的计划。 一般当产品的外型和组件的尺寸特点已经显现出来的时候，就可以进行全面的设计和分析。接着还要客观的分析机器性能、安全、重量、耐用性，并且成本也要考虑在内。每一个至关重要的部分要优化它的比例和尺寸，同时也要保持与其它组成部分的平衡。 选择原材料和工艺的方法。通过力学原理来分析和实现这些重要的特性，如稳定和反应的能量和摩擦力的利用，动力惯性、加速度、能量；包括材料的弹性强度、应力和刚度等物理特性，以及流体的润滑和驱动器的流体力学。设计的过程是一个反复与合作的过程，无论是正式的还是非正式的，对设计者来说每个阶段都很重要。。产品设计需要大量的研究和提升。许多的想法,必须通过努力去研究成为一种理念,然后去使用或放弃。
中等分辨率制备分离的 快速色谱技术 W. Clark Still,* Michael K a h n , and Abhijit Mitra Departm(7nt o/ Chemistry, Columbia Uniuersity,1Veu York, Neu; York 10027 ReceiLied January 26, 1978 我们希望找到一种简单的吸附色谱技术用于有机化合物的常规净化。这种技术是适于传统的有机物大规模制备分离，该技术需使用长柱色谱法。尽管这种技术得到的效果非常好，但是其需要消耗大量的时间，并且由于频带拖尾经常出现低复原率。当分离的样本剂量大于1或者2g时，这些问题显得更加突出。近年来，几种制备系统已经进行了改进，能将分离时间减少到1-3h，并允许各成分的分辨率ΔR f≥（使用薄层色谱分析进行分析）。在这些方法中，在我们的实验室中，媒介压力色谱法1和短柱色谱法2是最成功的。最近，我们发现一种可以将分离速度大幅度提升的技术，可用于反应产物的常规提纯，我们将这种技术称为急骤色谱法。虽然这种技术的分辨率只是中等（ΔR f≥），而且构建这个系统花费非常低，并且能在10-15min内分离重量在的样本。4 急骤色谱法是以空气压力驱动的混合介质压力以及短柱色谱法为基础，专门针对快速分离，介质压力以及短柱色谱已经进行了优化。优化实验是在一组标准条件5下进行的，优化实验使用苯甲醇作为样本，放在一个20mm*5in.的硅胶柱60内，使用Tracor 970紫外检测器监测圆柱的输出。分辨率通过持续时间（r）和峰宽（w,w/2）的比率进行测定的（Figure 1），结果如图2-4所示，图2-4分别放映分辨率随着硅胶颗粒大小、洗脱液流速和样本大小的变化。
陶瓷 ceramics 合成纤维 synthetic fibre 电化学腐蚀 electrochemical corrosion 车架 automotive chassis 悬架 suspension 转向器 redirector 变速器 speed changer 板料冲压 sheet metal parts 孔加工 spot facing machining 车间 workshop 工程技术人员 engineer 气动夹紧 pneuma lock 数学模型 mathematical model 画法几何 descriptive geometry 机械制图 Mechanical drawing 投影 projection 视图 view 剖视图 profile chart 标准件 standard component 零件图 part drawing 装配图 assembly drawing 尺寸标注 size marking
技术要求 technical requirements 刚度 rigidity 内力 internal force 位移 displacement 截面 section 疲劳极限 fatigue limit 断裂 fracture 塑性变形 plastic distortion 脆性材料 brittleness material 刚度准则 rigidity criterion 垫圈 washer 垫片 spacer 直齿圆柱齿轮 straight toothed spur gear 斜齿圆柱齿轮 helical-spur gear 直齿锥齿轮 straight bevel gear 运动简图 kinematic sketch 齿轮齿条 pinion and rack 蜗杆蜗轮 worm and worm gear 虚约束 passive constraint 曲柄 crank 摇杆 racker 凸轮 cams
机械设计理论 机械设计是一门通过设计新产品或者改进老产品来满足人类需求的应用技术科学。它涉及工程技术的各个领域，主要研究产品的尺寸、形状和详细结构的基本构思，还要研究产品在制造、销售和使用等方面的问题。 进行各种机械设计工作的人员通常被称为设计人员或者机械设计工程师。机械设计是一项创造性的工作。设计工程师不仅在工作上要有创造性，还必须在机械制图、运动学、工程材料、材料力学和机械制造工艺学等方面具有深厚的基础知识。如前所诉，机械设计的目的是生产能够满足人类需求的产品。发明、发现和科技知识本身并不一定能给人类带来好处，只有当它们被应用在产品上才能产生效益。因而，应该认识到在一个特定的产品进行设计之前，必须先确定人们是否需要这种产品。 应当把机械设计看成是机械设计人员运用创造性的才能进行产品设计、系统分析和制定产品的制造工艺学的一个良机。掌握工程基础知识要比熟记一些数据和公式更为重要。仅仅使用数据和公式是不足以在一个好的设计中做出所需的全部决定的。另一方面，应该认真精确的进行所有运算。例如，即使将一个小数点的位置放错，也会使正确的设计变成错误的。 一个好的设计人员应该勇于提出新的想法，而且愿意承担一定的风险，当新的方法不适用时，就使用原来的方法。因此，设计人员必须要有耐心，因为所花费的时间和努力并不能保证带来成功。一个全新的设计，要求屏弃许多陈旧的，为人们所熟知的方法。由于许多人墨守成规，这样做并不是一件容易的事。一位机械设计师应该不断地探索改进现有的产品的方法，在此过程中应该认真选择原有的、经过验证的设计原理，将其与未经过验证的新观念结合起来。 新设计本身会有许多缺陷和未能预料的问题发生，只有当这些缺陷和问题被解决之后，才能体现出新产品的优越性。因此，一个性能优越的产品诞生的同时，也伴随着较高的风险。应该强调的是，如果设计本身不要求采用全新的方法，就没有必要仅仅为了变革的目的而采用新方法。 在设计的初始阶段，应该允许设计人员充分发挥创造性，不受各种约束。即使产生了许多不切实际的想法，也会在设计的早期，即绘制图纸之前被改正掉。只有这样，才不致于堵塞创新的思路。通常，要提出几套设计方案，然后加以比较。很有可能在最后选定的方案中，采用了某些未被接受的方案中的一些想法。
机械专业英语词汇 陶瓷ceramics 合成纤维synthetic fibre 电化学腐蚀electrochemical corrosion 车架automotive chassis 悬架suspension 转向器redirector 变速器speed changer 板料冲压sheet metal parts 孔加工spot facing machining 车间workshop 工程技术人员engineer 气动夹紧pneuma lock 数学模型mathematical model 画法几何descriptive geometry 机械制图Mechanical drawing 投影projection 视图view 剖视图profile chart 标准件standard component 零件图part drawing 装配图assembly drawing 尺寸标注size marking 技术要求technical requirements 刚度rigidity 内力internal force 位移displacement 截面section 疲劳极限fatigue limit 断裂fracture 塑性变形plastic distortion 脆性材料brittleness material 刚度准则rigidity criterion 垫圈washer 垫片spacer 直齿圆柱齿轮straight toothed spur gear 斜齿圆柱齿轮helical-spur gear 直齿锥齿轮straight bevel gear 运动简图kinematic sketch 齿轮齿条pinion and rack 蜗杆蜗轮worm and worm gear 虚约束passive constraint 曲柄crank 摇杆racker 凸轮cams 共轭曲线conjugate curve 范成法generation method 定义域definitional domain 值域range 导数\\微分differential coefficient 求导derivation 定积分definite integral 不定积分indefinite integral 曲率curvature 偏微分partial differential 毛坯rough 游标卡尺slide caliper 千分尺micrometer calipers 攻丝tap 二阶行列式second order determinant 逆矩阵inverse matrix 线性方程组linear equations 概率probability 随机变量random variable 排列组合permutation and combination 气体状态方程equation of state of gas 动能kinetic energy 势能potential energy 机械能守恒conservation of mechanical energy 动量momentum 桁架truss 轴线axes 余子式cofactor 逻辑电路logic circuit 触发器flip-flop 脉冲波形pulse shape 数模digital analogy 液压传动机构fluid drive mechanism 机械零件mechanical parts 淬火冷却quench 淬火hardening 回火tempering 调质hardening and tempering 磨粒abrasive grain 结合剂bonding agent 砂轮grinding wheel 后角clearance angle 龙门刨削planing 主轴spindle
外文翻译 英文原文 Belt Conveying Systems Development of driving system Among the methods of material conveying employed，belt conveyors play a very important part in the reliable carrying of material over long distances at competitive cost．Conveyor systems have become larger and more complex and drive systems have also been going through a process of evolution and will continue to do so．Nowadays，bigger belts require more power and have brought the need for larger individual drives as well as multiple drives such as 3 drives of 750 kW for one belt(this is the case for the conveyor drives in Chengzhuang Mine)．The ability to control drive acceleration torque is critical to belt conveyors’ performance．An efficient drive system should be able to provide smooth，soft starts while maintaining belt tensions within the specified safe limits．For load sharing on multiple drives．torque and speed control are also important consideratio ns in the drive system’s design. Due to the advances in conveyor drive control technology，at present many more reliable．Cost-effective and performance-driven conveyor drive systems cov ering a wide range of power are available for customers’ choices[1]. 1 Analysis on conveyor drive technologies 1．1 Direct drives Full-voltage starters．With a full-voltage starter design，the conveyor head shaft is direct-coupled to the motor through the gear drive．Direct full-voltage starters are adequate for relatively low-power, simple-profile conveyors．With direct fu11-voltage starters．no control is provided for various conveyor loads and．depending on the ratio between fu11- and no-1oad power requirements，empty starting times can be three or four times faster than full load．The maintenance-free starting system is simple，low-cost and very reliable．However, they cannot control starting torque and maximum stall torque；therefore．they are
英文翻译 机械设计 一台完整机器的设计是一个复杂的过程。机械设计是一项创造性的工作。设计工程师不仅在工作上要有创造性，还必须在机械制图、运动学、工程材料、材料力学和机械制造工艺学等方面具有深厚的基础知识。 Machine Design The complete design of a machine is a complex process. The machine design is a creative work. Project engineer not only must have the creativity in the work, but also must in aspect and so on mechanical drawing, kinematics, engineerig material, materials mechanics and machine manufacture technology has the deep elementary knowledge. 任何产品在设计时第一步就是选择产品每个部分的构成材料。许多的材料被今天的设计师所使用。对产品的功能，它的外观、材料的成本、制造的成本作出必要的选择是十分重要的。对材料的特性必须事先作出仔细的评估。 One of the first steps in the design of any product is to select the material from which each part is to be made. Numerous materials are available to today's designers. The function of the product, its appearance, the cost of the material, and the cost of fabrication are important in making a selection. A careful evaluation of the properties of a. material must be made prior to any calculations. 仔细精确的计算是必要的，以确保设计的有效性。在任何失败的情况下，最好知道在最初设计中有有缺陷的部件。计算（图纸尺寸）检查是非常重要的。一个小数点的位置放错，就可以导致一个本可以完成的项目失败。设计工作的各个方面都应该检查和复查。 Careful calculations are necessary to ensure the validity of a design. In case of any part failures, it is desirable to know what was done in originally designing the defective components. The checking of calculations (and drawing dimensions) is of utmost importance. The misplacement of one decimal point can ruin an otherwise acceptable project. All aspects of design work should be checked and rechecked. 计算机是一种工具，它能够帮助机械设计师减轻繁琐的计算，并对现有数据提供进一步的分析。互动系统基于计算机的能力，已经使计算机辅助设计（CAD）和计算机辅助制造（CAM）成为了可能。心理学家经常谈论如何使人们适应他们所操作的机器。设计人员的基本职责是努力使机器来适应人们。这并不是一项容易的工作，因为实际上并不存在着一个对所有人来说都是最优的操作范围和操作
A Distributed Approach for Track Occupancy Detection Abstract This paper investigates the problem of track occupancy detection in distributed settings. Track occupancy detection determines which tracks are occupied in a railway system. For each track, the Neyman–Pearson structure is applied to reach the local decision. Globally, it is a multiple hypotheses testing problem. The Bayesian approach is employed to minimize the probability of the global decision error. Based on the prior probabilities of multiple hypotheses and the approximation of the prior probabilities of multiple hypotheses and the approximationofthereceiving operation characteristic curve of the local detector, a person-by-person optimization method is implemented to obtain the fusion rule and the local strategies off line. The results are illustrated through an example constructed from in situ devices. Key Words:Track occupancy detection,Neyman–Pearson, Generalized likelihood ratio test, Bayesian approach,Distributed detection 1Introduction With respect to the majority of railway systems in China, a quasi-moving block method is employed to specify the safe zone of a train. A key piece of knowledge to be determined is the set of track segments that are occupied, i.e., track occupancy detection. Then the speed restriction curves for the following trains are calculated accordingly. When there are misdetections, collisions may happen; additionally, false alarms may lead to declines of line capacity. Track occupancy detection is achieved by a set of track circuits. The track circuit is a crucial device mainly composed of a transmitter–receiver pair and a track segment. The measurement is the receiving signal at the end of the track. For each segment, a decision is made locally and individually, which leads to frequent ambiguities on which tracks are occupied for the whole line. It means that the false alarm rate of the line increases greatly. Besides, for the next generation of railway systems, a moving block method is adopted. Such a method requires the exact position and velocity of the train. However, those data are not provided in the current detection mechanism.
近几年，我厂和英国、西班牙的几个公司有业务往来，外商传真发来的图纸都是英文标注，平时阅看有一定的困难。下面把我们积累的几点看英文图纸的经验与同行们交流。 1标题栏 英文工程图纸的右下边是标题栏（相当于我们的标题栏和部分技术要求），其中有图纸名称（TILE）、设计者（DRAWN）、审查者（CHECKED）、材料（MATERIAL）、日期（DATE）、比例（SCALE）、热处理（HEAT TREATMENT）和其它一些要求，如： 1)TOLERANCES UNLESS OTHERWISE SPECIFIAL 未注公差。 2)DIMS IN mm UNLESS STATED 如不做特殊要求以毫米为单位。 3)ANGULAR TOLERANCE±1°角度公差±1°。 4)DIMS TOLERANCE±0.1未注尺寸公差±0.1。 5)SURFACE FINISH 3.2 UNLESS STATED未注粗糙度3.2。 2常见尺寸的标注及要求 2.1孔（HOLE）如： （1）毛坯孔：3"DIAO+1CORE 芯子3"0+1; （2）加工孔：1"DIA1"; （3）锪孔：锪孔(注C＇BORE=COUNTER BORE锪底面孔); （4）铰孔：1"/4 DIA REAM铰孔1"/4; （5）螺纹孔的标注一般要表示出螺纹的直径，每英寸牙数（螺矩）、螺纹种类、精度等级、钻深、攻深，方向等。如： 例1.6 HOLES EQUI-SPACED ON 5"DIA (6孔均布在5圆周上（EQUI-SPACED=EQUALLY SPACED均布） DRILL 1"DIATHRO＇ 钻1"通孔（THRO＇=THROUGH通） C/SINK22×6DEEP 沉孔22×6 例2.TAP7"/8-14UNF-3BTHRO＇ 攻统一标准细牙螺纹，每英寸14牙，精度等级3B级 （注UNF=UNIFIED FINE THREAD美国标准细牙螺纹） 1"DRILL 1"/4-20 UNC-3 THD7"/8 DEEP 4HOLES NOT BREAK THRO钻 1"孔，攻1"/4美国粗牙螺纹，每英寸20牙，攻深7"/8,4孔不准钻通（UNC=UCIFIED COARSE THREAD 美国标准粗牙螺纹）
Title: Modelling of transport costs and logistics for on-farm milk segregation in New Zealand dairying Material Source: Computers and Electronics in Agriculture Author: A. E. Dooley, Parker, H. T. Blair Abstract On-farm milk segregation to keep milk with high value properties separate from bulk milk will affect transport logistics. Separate milk collection, either as independent runs for different milk types,or storage of distinct milk types in the truck and trailer units, may increase the length and number of runs required. Two contrasting regions,with different farm sizes and roading networks were modelled,at two stages of lactation over 20 years. Thirty farms in each region were modelled with 0, 25, 50 and 100% of farms per region changing milk types over a transition period of up to 18 years. Genetic algorithm software was used to search for the order of the farm milk collection pick-ups which gave an optimal, least cost solution for milk collection for each prescribed set of inputs. Milk collection costs within scenario were variable over time depending on the amounts of the different milk types, increasing whenever another run was required, then decreasing over time as the milk load increased. Milk collection cost is small relative to milk income, with the status quo (SQ) cost for milk collection being less than NZ$9.61/kl for the North Island and NZ$13.53/kl for the South Island farm sets. The increased transport costs associated with collecting two milk types ranged from 4.5 to 22.0% more for the different scenarios. The extra cost to an average size North Island farm changing systems (25% farms changing), compared to an equivalent status quo farm, would be between NZ$307 and NZ$1244 per year. Fewer farms changing to differentiated milk production increased the costs per kilolitre of differentiated milk. Keywords: Milk transport; Scheduling; Milk segregation; Collection costs 1.Introduction
英文资料 Limits and Tolerances The breakage of the machine spare parts ,generally always from the surface layer beginning of .The function of the product ,particularly its credibility and durable ,be decided by the quantity of spare parts surface layer to a large extent. Purpose that studies the machine to process the surface quantity be for control the machine process medium various craft factor to process the surface quantity influence of regulation, in order to make use of these regulations to control to process the process, end attain to improve the surface quantity, the exaltation product use the function of purpose . The machine processes the surface quantity to use the influence of the function to the machine (A) The surface quantity to bear to whet the sexual influence 1.Rough degree of surface to bear to whet the sexual influence A just process vice-of two contact surfaces of good friction, the first stage is rough only in the surface of the peak department contact ,the actual contact area is much smaller than theoretical contact area, in contact with each other the peak of the units have very great stress, to produce actual contact with the surface area of plastic deformation, deformation and peak between the Department of shear failure, causing serious wear. Parts wear may generally be divided into three stages, the initial stage of wear and tear, normal wear and tear all of a sudden intense phase of stage wear. Parts of the surface roughness of the surface wear big impact. In general the smaller the value of surface roughness, wear better. However, surface roughness value is too small, lubricants difficult to store, contact between the adhesive-prone elements, wear it to increase. Therefore, the surface roughness of a best value, the value and parts of the work related to increased work load, the initial wear increased, the best rough surface is also increased. 2.Cold Working hardening the surface of the wear resistance Processing the Cold Work hardening the surface of the friction surface layer of metal microhardness increase, it will generally improve the wear resistance. Cold Working but not a higher degree of hardening, wear resistance for the better, because too much will lead to hardening of the Cold Working excessive loose organization of
VOLUME 30 ISSUE 2 October 2008 Journal of Achievements in Materials and Manufacturing Engineering Copyright by International OCSCO World Press. All rights reserved.2008 151 Research paper 2008年十月期2卷30 材料与制造工程成果期刊 版权所有：国际OCSCO 世界出版社。一切权利保有。2008 ？？151研究论文 1. Introduction Friction stir welding (FSW) is a new solid-state welding method developed by The Welding Institute (TWI) in 1991 [1]. The weld is formed by the excessive deformation of the material at temperatures below its melting point, thus the method is a solid state joining technique. There is no melting of the material, so FSW has several advantages over the commonly used fusion welding techniques [2-10]. 1.导言摩擦搅拌焊接（FSW）是焊接学？会于1991年研发的一种新型固态焊接方法。这种焊接？是由材料在低于其熔点的温度上过量变形形成，因此此技术是一种固态连接技术。材料不熔化，所以FSW 相比常用的熔化焊接技术有若干优势。例如，在焊接区无多孔性或破裂，工件（尤其薄板上）没有严重扭曲，并且在连接过程中不需要填料、保护气及昂贵的焊接准备there is no significant distortion of the workpieces (particularly in thin plates), and there is no need for filler materials, shielding gases and costly weld preparation during this joining process. FSW被认为是对若干材料例如铝合金、镁合金、黄铜、钛合金及钢最显著且最有潜在用途的焊接技术FSW is considered to be the most remarkable and potentially useful welding technique for several materials, such as Al-alloys, Mg-alloys, brasses, Ti-alloys, and steels [1-16]. 然而，在FSW过程中，用不合适的焊接参数能引起连接处失效，并且使FSW连接处的力学性能恶化。However, during FSW process using inappropriate welding parameters can cause defects in the joint and deteriorate the mechanical properties of the FSW joints [2, 3]. 此技术起初就主要是为低熔点材料如铝合金、镁合金及铜合金而广泛研究的。The technique has initially been widely investigated for mostly low melting materials, such as Al, Mg and Cu alloys. 此技术已被证明是很有用的，尤其在连接用于航空航天用途的如高合金2XXX及7XXX系列铝合金等难熔高强度的铝合金。It has proven to be very useful, particularly in the joining of the difficult-to-fusion join high strength Al-alloys used in aerospace applications, such as highly alloyed 2XXX and 7XXX series aluminium alloys. 做出Al-5086 H32型板摩擦搅拌对焊的高强度、抗疲劳及断裂的力学性能？。The difficulty of making high-strength, fatigue and fracture resistant Mechanical properties of friction stir butt-welded Al-5086 H32 plate G. .am a,*, S. Gü.lüer b, A. .akan c, H.T. Serinda. a a Mustafa Kemal University, Faculty of Engineering and Architecture, 31040 Antakya, Turkey a 土耳其安塔卡亚31040，Mustafa Kemal大学建筑工程系 b General Directorate of Highways of Turkey, Ankara, Turkey b 土耳其安卡拉土耳其高速公路总理事会？ c Abant Izzet Baysal University, Faculty of Engineering an d Architecture, 14280 Bolu, Turkey c 土耳其Bolu 14280 Abant Izzet Baysal 大学建筑工程系 * Corresponding author: E-mail address: gurelcam@https://www.doczj.com/doc/4e1166366.html, *相关作者电子邮箱地址：gurelcam@https://www.doczj.com/doc/4e1166366.html, Received 30.06.2008; published in revised form 01.10.2008