外文文献：
Switching Power Supply Design
Switching power supply work in high frequency, high pulse state, are analog circuits in a rather special kind. Cloth boards to follow the principle of high-frequency circuit wiring.
First, layout:
Pulse voltage connection as short as possible, including input switch connected to the transformer, output transformer to the rectifier tube cable. Pulse current loop as small as possible such as the input filter capacitor is returned to the transformer to the switch capacitor negative. Some out-ended output transformers are the output rectifier to the output capacitor back to transformer circuit X capacitor as close as possible to the input switching power supply, input lines should be avoided in parallel with other circuits, should be avoided. Y capacitor should be placed in the chassis ground terminal or FG connectors. A total of touch induction and transformer to maintain a certain distance in order to avoid magnetic coupling. Such as poor handling of feeling in between inductor and transformer plus a shield, over a number of EMC performance for power supply to the greater impact.
General the output capacitor can be used the other two a close rectifier output terminal should be close to, can affect the power supply output ripple index, two small capacitor in parallel results should be better than using a large capacitor. Heating devices to maintain a certain distance, and electrolytic capacitors to extend machine life, electrolytic capacitors is the switching power supply bottleneck life, such as transformers, power control, high power resistors and electrolytic to maintain the distance required between the electrolyte leaving space for heat dissipation , conditions permitting, may be placed in the inlet.
Control part to pay attention to: Weak signal high impedance circuit connected to sample the feedback loop as short as in the processing as far as possible avoid interference, the current sampling signal circuits, in particular the current control circuit, easy to deal with some unexpected bad The accident, which had some skill,
now to 3843 the circuit example shown in Figure (1) Figure 1 better than Yu Figure 2, Figure 2 Zai full time by observing the current waveform oscilloscope Mingxian superimposed spikes, Youyuganrao limited flow ratio design Zhi Dian low, Figure 1 there is no such phenomenon, there are switch drive signal circuit, switch resistance should be close to the switch driver can switch the work to improve the reliability of this and the high DC impedance voltage power MOSFET driver characteristics. Second, routing
Alignment of current density: now the majority of electronic circuit board using insulated copper constitute tied. Common PCB copper thickness of 35μm, the alignment value can be obtained in accordance with 1A/mm experience the value of current density, the specific calculations can be found in textbooks. To ensure the alignment principles of mechanical strength should be greater than or equal to the width of 0.3mm (other non-power supply circuit board may be smaller minimum line width). PCB copper thickness of 70μm is also common in switching power supply, then the current density can be higher.
Add that, now Changyong circuit board design tool design software generally items such as line width, line spacing, hole size and so dry plate Guo Jin Xing parameters can be set. In the design of circuit boards, design software automatically in accordance with the specifications, can save time, reduce some of the workload and reduce the error rate.
Generally higher on the reliability of lines or line density wiring can be used double panel. Characterized by moderate cost, high reliability, to meet most applications.
The ranks of some of the power module products are also used plywood, mainly to facilitate integration of power devices such as transformer inductance to optimize wiring, cooling and other power tube. Good consistency with the craft beautiful, transformer cooling good advantage, but its disadvantage is high cost, poor flexibility, only suitable for industrial mass production.
Single-sided, the market circulation of almost universal switching power supply using single-sided circuit board, which has the advantage of lower costs in the
design and production technology are also taken some measures to ensure its performance.
Single PCB design today to talk about some experience, as a single panel with low cost, easy-to-manufacture features, the switching power supply circuit has been widely used, because of its side tied only copper, the device's electrical connections, mechanical fixation should rely on the copper layer, the processing must be careful. To ensure good performance of the mechanical structure welding, single-sided pad should be slightly larger to ensure that the copper and substrate tied good focus, and thus will not be shocked when the copper strip, broken off. General welding ring width should be greater than 0.3mm. Pad diameter should be slightly larger than the diameter of the device pins, but not too large, to ensure pin and pad by the solder connection between the shortest distance, plate hole size should not hinder the normal conditions for the degree of investigation, the pad diameter is generally greater than pin diameter 0.1-0.2mm. Multi-pin device to ensure a smooth investigation documents can also be larger.
Electrical connection should be as wide as possible, in principle, should be larger than the width of pad diameter, special circumstances should be connected in line with the need to widen the intersection pad (commonly known as Generation tears), to avoid breaking certain conditions, line and pad. Principle of minimum line width should be greater than 0.5mm.
Single-board components to be close to the circuit board. Need overhead cooling device to device and circuit board between the pins plus casing, can play a supporting device and increase the dual role of insulation to minimize or avoid external shocks on the pad and the pin junction impact and enhance the firmness of welding. Circuit board supporting the weight of large parts can increase the connection point, can enhance joint strength between the circuit board, such as transformers, power device heat sink.
Single-sided welding pins without affecting the surface and the shell spacing of the prior conditions, it can be to stay longer, the advantage of increased strength of welded parts, increase weld area and immediately found a Weld phenomenon. Shear
pin long legs, the welding force smaller parts. In Taiwan, the Japanese often use the device pins in the welding area and the circuit board was bent 45 degrees, and then welding process, its reasoning Ibid. Double panel today to talk about the design of some of the issues, in relatively high number of requests, or take the line density of the larger application environments using double-sided PCB, its performance and various indicators of a lot better than a single panel.
Two-panel pad as holes have been high intensity metal processing, welding ring smaller than a single panel, the pad hole diameter slightly larger in diameter than pins, as in the welding process solder solution conducive to penetrate through the top hole solder pad to increase the welding reliability. But there is a disadvantage if the hole is too large, wave soldering tin when the jet impact in the lower part of the device may go up, have some flaws.
High current handling of alignment, line width in accordance with pre-quote processing, such as the width is not enough to go online in general can be used to increase the thickness of tin plating solution, the method has a good variety of
1. Will take the line set to pad property, so that when the circuit board manufacturing solder alignment will not be covered, the whole hot air normally be tin plated.
2. In the wiring by placing pads, the pad is set to take in line shape, pay attention to the pad holes set to zero.
3. In the solder layer placed on line, this method is the most flexible, but not all PCB manufacturers will understand your intentions, needed captions. Place the line in the solder layer of the site will not coated solder tinning line several methods as above, to note that, if the alignment of a very wide all plated with tin in solder after the solder will bond a lot and distribution is very uneven, affecting appearance. Article tin can be used generally slender width in the 1 ~ 1.5mm, length can be determined according to lines, tin part of the interval 0.5 ~ 1mm
Double-sided circuit board for the layout, the alignment provides a very selective, make wiring more reasonable. On the ground, the power ground and signal ground must be separated, the two to converge in filter capacitors, in order to avoid a large pulsed current through the signal ground connection instability caused by unexpected
factors, the signal control circuit grounding point as far as possible, a skill, as far as possible the alignment of the non-grounded wiring layer in the same place, the last shop in another layer of earth. Output line through the filter capacitors, the general first, and then to the load, input line must also pass capacitor, to the transformer, the theoretical basis is to ripple through trip filter capacitor.
V oltage feedback sampling, in order to avoid high current through the alignment of the feedback voltage on the sampling point must be the most peripheral power output to increase the load effect of target machine.
Alignment change from a wiring layer to another wiring layer generally used hole connected, not through the pin pad device to achieve, because the plug in the device may be damaged when the relationship between this connection, there is current in every passage of 1A, at least two through-hole, through hole diameter is greater than the principle of 0.5mm, 0.8mm generally processed ensure reliability.
Cooling devices, in some small power supply, the circuit board traces can be and cooling, characterized by the alignment as generous as possible to increase the cooling area is not coated solder, conditions can even be placed over holes, enhanced thermal conductivity .
Today to talk about the aluminum plate in the switching power supply application and multilayer printed circuit in the switching power supply applications.
Aluminum plate by its own structure, has the following characteristics: very good thermal conductivity, single Mianfu copper, the device can only be placed in tied copper surface, can not open electrical connection hole so as not to place jumper in accordance with a single panel.
Aluminum plate is generally placed patch device, switch, the output rectifier heat conduction through the substrate to go out, very low thermal resistance, high reliability can be achieved. Transformer with planar chip structure, but also through substrate cooling, the temperature is lower than the conventional, the same size transformer with a large aluminum plate structure available output power. Aluminum plate jumper bridge approach can be used. Aluminum plate power are generally composed by the two PCB, another one to place the control circuit board, through the
physical connection between the two boards is integrated.
As the excellent thermal conductivity of aluminum plate, in a small amount of manual welding more difficult, solder cooling too fast and prone to problems of a simple and practical way of existing, an ironing ordinary iron (preferably temperature regulation function), over and iron for the last, fixed, and temperature to 150 ℃ and above the aluminum plate on the iron, heating time, and then affix the components according to conventional methods and welding, soldering iron temperature is appropriate to the device easy to , is too high when the device may be damaged, or even copper strip aluminum plate, the temperature is too low welding effect is not good, to be flexible. Recent years, with the multi-layer circuit board applications in switching power supply circuit, printed circuit transformer makes it possible, due to multilayer, smaller spacing also can take advantage of Bianya Qi window section, the main circuit board can be re- Add 1-2 formed by the multilayer printed coil to use the window, the purpose of reducing circuit current density, due to adopt printed coil, reducing manual intervention, transformers consistency, surface structure, low leakage inductance, coupling good . Open-type magnetic core, good heat dissipation. Because of its many advantages, is conducive to mass production, it is widely used. But the research and development of large initial investment, not suitable for small-scale health. Switching power supply is divided into, two forms of isolation and non-isolated, isolated here mainly to talk about switching power supply topologies form below, non-specified, are to isolate the power. Isolated power supply in accordance with the structure of different forms, can be divided into two categories: a forward and flyback. Flyback transformer primary side means that when the Vice-edge conduction cut-off, transformer storage. Close of the primary, secondary side conduction, the energy released to the load of work status, general conventional flyback power multiplex, twin-tube is not common. Forward refers to the primary conduction in transformer secondary side while the corresponding output voltage is induced into the load, the direct transfer of energy through the transformer. According to specifications can be divided into conventional forward, including the single-transistor forward, Double Forward. Half-bridge, bridge circuits are all forward circuit.
Forward and flyback circuits have their own characteristics in the process of circuit design to achieve optimal cost-effective, can be applied flexibly. Usually in the low-power flyback can be adopted. Slightly larger forward circuit can use a single tube, medium-power can use Double Forward circuit or half-bridge circuit, low-voltage push-pull circuit, and the half-bridge work in the same state. High power output, generally used bridge circuit, low voltage can be applied push-pull circuit. Flyback power supply because of its simple structure, and to cut the size of a similar size and transformer inductance, the power supply in the medium has been widely applied. Presentation referred to in some flyback power supply can do dozens of watts, output power exceeding 100 watts would be no advantage to them difficult. Under normal circumstances, I think so, but it can not be generalized, PI's TOP chips can do 300 watts, an article describes the flyback power supply can be on the KW, but not seen in kind.
Power output and the output voltage level.
Flyback power transformer leakage inductance is a critical parameter, because the power needs of the flyback transformer stored energy, to make full use of transformer core, the general must be open in the magnetic circuit air gap, the aim is to change the core hysteresis back line of the slope, so that transformers can withstand the impact of a large pulse current, which is not core into saturation non-linear state, the magnetic circuit in the high reluctance air gap in the state, generated in the magnetic flux leakage is much larger than completely closed magnetic circuit .
Transformer coupling between the first pole is the key factor determining the leakage inductance, the coil to be very close as far as possible the first time, the sandwich can be used around the law, but this would increase the distributed capacitance transformer. Use core as core with a long window, can reduce the leakage inductance, such as the use of EE, EF, EER, PQ-based EI type magnetic core effective than good. The duty cycle of flyback power supplies, in principle, the maximum duty cycle of flyback power supply should be less than 0.5, otherwise not easy loop compensation may be unstable, but there are some exceptions, such as the U.S. PI has introduced the TOP series chip can work under the conditions of duty cycle is greater than 0.5.
Duty cycle by the transformer turns ratio to determine former deputy side, I am an anti-shock view is, first determine the reflected voltage (output voltage reflected through the transformer coupling the primary voltage value), reflecting a certain voltage range of voltage increase is duty cycle increases, lower power loss. Reduce the reflected voltage duty cycle decreases, increases power loss. Of course, this is a prerequisite, when the duty cycle increases, it means that the output diode conduction time, in order to maintain output stability, more time will be to ensure that the output capacitor discharge current, the output capacitor will be under even greater high-frequency ripple current erosion, while increasing its heat, which in many circumstances is not allowed.
Duty cycle increases, change the transformer turns ratio, transformer leakage inductance will increase, its overall performance change, when the leakage inductance energy large enough, can switch to fully offset the large account space to bring low-loss, no further increase when the meaning of duty, because the leakage inductance may even be too high against the peak voltage breakdown switch. Leakage inductance as large, may make the output ripple, and other electromagnetic indicators deteriorated. When the duty hours, the high RMS current through the switch, transformer primary current rms and lowered the converter efficiency, but can improve the working conditions of the output capacitor to reduce fever. How to determine the transformer reflected voltage (duty cycle)
Some netizens said switching power supply feedback loop parameter settings, work status analysis. Since high school mathematics is rather poor, "Automatic Control Theory," almost on the make-up, and for the door is still feeling fear, and now can not write a complete closed-loop system transfer function, zero for the system, the concept of feeling pole vague, see Bode plot is only about to see is a divergence or convergence, so the feedback compensation can not nonsense, but there are a number of recommendations. If you have some mathematical skills, and then have some time to learn then the University of textbooks, "Principles of Automatic Control" digest look carefully to find out, combined with practical switching power supply circuit, according to the work of state for analysis. Will be harvested, the Forum has a
message, "coach feedback loop to study the design, debugging," in which CMG good answer, I think we can reference.
Then today, on the duty cycle of flyback power supply (I am concerned about the reflected voltage, consistent with the duty cycle), the duty cycle with the voltage selection switch is related to some early flyback switching power supply using a low pressure tube, such as 600V or 650V AC 220V input power as a switch, perhaps when the production process, high pressure tubes, easy to manufacture, or low-pressure pipes are more reasonable conduction losses and switching characteristics, as this line reflected voltage can not be too high, otherwise the work order to switch the security context of loss of power absorbing circuit is quite impressive.
Reflected voltage 600V tube proved not more than 100V, 650V tube reflected voltage not greater than 120V, the leakage inductance voltage spike when the tubes are clamped at 50V 50V working margin. Now that the MOS raise the level of manufacturing process control, flyback power supplies are generally used 700V or 750V or 800-900V the switch. Like this circuit, overvoltage capability against a number of switching transformer reflected voltage can be done a bit higher, the maximum reflected voltage in the 150V is appropriate, to obtain better overall performance.
TOP PI's recommendation for the 135V chipset with transient voltage suppression diode clamp. But his evaluation board generally reflected voltage to be lower than the value at around 110V. Both types have their advantages and disadvantages: Category: shortcomings against over-voltage, low duty cycle is small, a large pulse current transformer primary. Advantages: small transformer leakage inductance, electromagnetic radiation and low ripple index higher switch loss, the conversion efficiency is not necessarily lower than the second.
The second category: a large number of shortcomings of power loss, a large number of transformer leakage inductance, the ripple worse. Advantages: Some strong against over-voltage, large duty cycle, lower transformer losses and efficiency higher. Reflected voltage flyback power supply and a determining factor
Reflected voltage flyback power supply with a parameter related to that is the output
voltage, output voltage, the lower the larger the transformer turns ratio, the greater the transformer leakage inductance, switch to withstand higher voltage breakdown switch is possible to absorb power consumption is higher, has the potential to permanently absorb the circuit power device failure (particularly with transient voltage suppression diode circuits). In the design of low-voltage low-power flyback power output optimization process must be handled with care, its approach has several:
1, using a large core of a power level lower leakage inductance, which can improve the low-voltage flyback power conversion efficiency, reduce losses, reduce output ripple and improve multi-output power of the cross regulation in general is common in household appliances with a switch power, such as CD-ROM drive, DVB set-top boxes.
2, if the conditions were not increased core, can reduce the reflected voltage, reducing the duty cycle. Reduce the reflected voltage can reduce the leakage inductance but may reduce the power conversion efficiency, which is a contradiction between the two, must have an alternative process to find a suitable point, replace the transformer during the experiment can detect the transformer original side of the anti-peak voltage, peak voltage to minimize the anti-pulse width, and magnitude of the work safety margin increase converter. Generally reflected voltage 110V when appropriate.
3, enhance the coupling, reducing losses, the introduction of new technologies, and the routing process, transformers to meet the security specifications will between the primary and secondary side to insulation measures, such as pad tape, plus side air insulation tape. These will affect the performance of transformer leakage inductance, the reality can be used in production around the primary winding secondary wrapping method. Or sub-system with a triple insulated wire wound to remove the insulation between the initial level, can enhance the coupling, even use wide copper winding. The article refers to low voltage output is less than or equal to 5V output, as this type of small power supply, my experience is that the power output of more than 20W output can use a forward, get the best value for money, of course, this is not the right decision , and personal habits, relationship between the application environment, the next time to talk about the flyback power supply with a magnetic core, magnetic
circuit air gap opening some understanding, I hope you receive adequate guidance. Flyback power transformer core magnetization state at work in one way, it needs to open the air gap magnetic circuit, similar to the pulsating direct current sensor. Part of the magnetic coupling through the air gap. Why I understand the principle of open air gap as follows: As the power ferrite also has a similar rectangle of the operating characteristics (hysteresis loop), operating characteristics curve in the Y-axis magnetic induction (B), now the general production process saturation point in 400mT above, the general value in the design of this value should be more appropriate in the 200-300mT, X-axis magnetic field strength (H) the value of current intensity is proportional to the magnetization. Open magnetic circuit air gap equal to the magnetic hysteresis loop to the X axis tilt, in the same magnetic induction intensity, can withstand a greater magnetizing current, equivalent to core store more energy, this energy cut-off switch When spilled into the load through the transformer secondary circuit, flyback power core to open the air gap is twofold. One is to transfer more energy, and the second to prevent the core into saturation.
Flyback Power Transformer magnetization state in one way, not only to pass through the magnetic coupling energy, is also responsible for input and output isolation voltage transform multiple roles. Therefore, the treatment gap need to be very careful, the air gap leakage inductance can become too large, increase the hysteresis loss, iron loss, copper loss increases, affecting the power of the whole performance. Air gap is too small has the potential to transformer core saturation, resulting in damage to power
The so-called flyback power supply is continuous and discontinuous mode transformer working conditions, working in full load condition in the power transformer complete transfer, or incomplete transmission mode. General design of the working environment, conventional flyback power supply should work in continuous mode, this switch, circuit loss are relatively small, and can reduce the stress of work input and output capacitors, but that there are some exceptions. Requires in particular that: As the characteristics of the flyback power supply is also more suitable for design into a high-voltage power supply, and high-voltage power
transformers generally work in discontinuous mode, I understand the need for as high voltage power supply output voltage of the rectifier diodes. Because of the manufacturing process characteristics, high-tension diode, reverse recovery time is long, low speed, the current continuous state, the diode has a positive bias in the recovery, reverse recovery energy loss is very large, is not conducive to converter performance increase, ranging from reduced conversion efficiency, rectifiers, severe fever, weight is even burnt rectifier. As in the intermittent mode, the diode is reverse biased under zero bias, loss can be reduced to a relatively low level. Therefore, high voltage power supply work in discontinuous mode, and the frequency can not be too high.
Another type of flyback power supply work in the critical state, the general type of power supply work in FM, or FM-width-modulated dual-mode, a number of low-cost self-excitation power (RCC) is often used this form in order to ensure stable output transformer As the operating frequency, output current or input voltage change, close to the fully loaded transformer is always maintained at between continuous and intermittent, this power is only suitable for small power output, otherwise the handling characteristics of electromagnetic compatibility will be a headache Flyback switching power supply transformer should work in continuous mode, it required relatively large winding inductance, of course, is to some extent continuous, excessive pursuit of absolute continuity is not realistic, may need a great core, very much coil turns, accompanied by a large leakage inductance and distributed capacitance, worth the trouble. So how does this parameter to determine, through repeated practice, and analysis of peer design, I think, in the nominal voltage input, the output reached 50% and 60% transformer from intermittent, continuous state of transition to more appropriate. Or at the highest input voltage state, the full output, the transformer can transition to the continuous state on it.
中文译文：
开关电源设计
开关电源状态，电源工作在高频率，高脉冲的模拟电路的一个比较特殊的一
种。布板布线原则遵循高频电路。
一，布局：
脉冲电压连接尽可能短，包括输入开关连接到变压器，输出变压器的整流管电缆。脉冲电流回路尽可能小，如输入滤波电容的负返回变压器开关电容器。一些外端输出变压器，输出整流变压器电路X电容尽可能靠近开关电源的输入输出电容，输入线能避免与其他电路平行的，应该尽量避免。Y电容应放置在机箱的接地端子或FG连接器。一个触摸感应和变压器总要保持一定的距离，以避免磁耦合。
总的输出电容可以使用的其他两个紧密整流器输出端应接近，可能会影响电源的输出纹波指标，两个小电容并联电容器的结果应该比使用大。加热装置要保持一定的距离，电解电容，延长机器寿命，铝电解电容器是开关电源的供电瓶颈，如变压器，电源控制，高功率电阻器和电解空间的距离为维持电解质之间需要离开耗散，条件允许的话，可能被放置在入口。
控制部分要注意：高阻抗电路连接到样品的反馈回路短弱信号处理中尽量避免干扰，电流采样信号的电路，特别是电流控制电路，容易处理一些意想不到坏的事故，其中有一些技巧.
二，路径
对准电流密度：现在大部分的电路板使用绝缘铜电子构成并列。常见的PCB 铜层厚度35μm，标准值为1A/mm，按照目前的密度值，具体计算可以参考教科书。为了确保机械强度的对齐原则应大于或等于0.3毫米宽（其他非电源电路板可能会为更小的最小线条宽度）。PCB的厚度为70μm铜也是常见的开关电源供应，则电流密度可以更高。
补充一点，现在常用电路板设计工具设计软件性参数，一般的项目，如线宽，线间距，孔大小等数值可根据Guo Jin Xing参量设置。在电路板的设计，设计软件自动按照规格，可以节省时间，减少工作量，减少一些错误率。
一般来说,更高的可靠性,在线或线密度布线可用于双面板。其特点是价格适中，可靠性高，能满足大多数应用。
一些产品的电源模块行列，也被用于胶合板，主要是方便设备的集成，如电力变压器电感优化布线，制冷等行业的功率管。良好的一致性与工艺美观，变压器冷却良好的优势，但其缺点是成本高，弹性差，只适合于工业化大生产。
单面，电力供应市场上流通使用的几乎是普遍的切换单双面电路板，它具有技术优势和生产成本较低的设计，也采取了一些措施，以确保其性能。
单PCB设计，今天谈一些经验，为制造功能单一的面板，成本低，易于开关电源的电路已被广泛使用，因为它的边绑只有铜，设备的电气连接，机械固定要依靠铜层，处理一定要慎重。
为了保证焊接结构件的机械性能良好，单面垫应该再大一点，以确保良好的铜和基材并列焦点，因而不会感到震动时，铜带，折断。一般焊接环宽度应大于0.3毫米。焊盘直径应略大于销直径的设备，但不太大，确保了最短的距离引脚和焊盘之间的连接由焊料，板孔尺寸应不妨碍调查的正常程度的条件，垫直径一般大于销直径0.1 - 0.2mm的。多针装置，确保顺利调查元件也可以较大。电气连接应尽可能广泛，原则上应直径大于垫宽度，特殊情况应连接线的需要扩阔路口垫（通常称为泪水代），以避免破坏某些条件，线，垫。最小线条宽度原则应大于0.5毫米。
单板组件接近电路板。需要冷却设备到设备的开销和电路板之间加套管针，可以起到支撑装置，提高保温的双重作用，尽量减少或避免外部冲击的影响交界
的垫脚，提高了焊接的坚定性。电路板支持点的大部分重量可以增加连接，可以提高连接强度板，如变压器之间的电路，功率器件的散热片。
间距的先决条件单面焊脚没有外壳表面和影响，它可以延长逗留时间，增加了区位优势的焊接部位的强度，提高焊接，立即找到了焊缝的现象。剪脚长的腿，焊接力较小的部分。在台湾，日本人经常使用的焊接领域的器件引脚和电路板中的弯曲45度，然后焊接过程中，其理由同上。双面板今天谈论的问题，设计了一些，在相对高的要求下，或采取双面PCB的线路密度的两倍大的应用环境使用，其性能和各项指标比单面板的好多了。
双面板焊盘孔已高强度的金属加工，焊接环小于单面板，焊盘孔直径稍大的直径比，因为在焊接过程中焊垫的解决方案有利于穿透顶端孔焊垫提高焊接的可靠性。但是有一个缺点，如果孔太大，波峰焊锡时射流冲击可能会在设备下部，也有一些缺陷。
高电流处理对齐，宽度根据预先报价处理，如宽度不够上线一般可用于增加锡层厚度的电镀液，该方法具有良好的多种
1. 将采取设置为填充属性，这样，当电路板制造焊接校准将不包括在内，整个热空气通常是镀锡。
2.在布线设置垫，垫设定线条造型时，注意垫孔设置为零。
3.在上线放置一层焊锡，这种方法是最灵活的，但不是所有的PCB制造商能够理解你的意图，需要说明文字。安置线在站点的焊剂层数将没有装罐线的上漆的焊剂几个方法如上所述，注意，如果所有路线很广锡焊料镀后焊将焊接很多，分布极不均匀，影响美观。可以使用一般细长条的宽度在1~1.5mm，长度可根据线路，锡部分区间确定为0.5～1mm。
电压反馈取样，以避免高电流通过采样点的反馈电压调整的必须是最外围功率输出，以增加目标负载效应。
对准变化从一个布线层布线层到另一个洞一般用于连接实现的，而不是通过密码键盘设备，因为设备插上时，可能会损坏连接之间的关系这一点，在每一个有电流通过的每1A，在至少有两个通孔，通孔直径大于0.5毫米的原则，一般为0.8mm 处理确保可靠性。
冷却装置，在一些小型电源，电路板走线可以和冷却的电路板一样，对齐特点是尽可能广，以增加散热面积是不带涂层焊接，甚至可以放置在孔，增强导热性。
今天来谈谈电源应用铝塑板在开关电源的开关电源的应用及多层印刷电路研究。
铝结构钢板基于自己的结构，具有以下特点：非常良好的热传导性，单Mianfu 铜，设备只能放置在铜表面的束缚，无法打开电气连接孔，以便按照单一面板跳线。
铝合金板一般放置修补设备，开关，输出整流器通过的基板热传导，热阻非常低，可靠性高，是可以实现的。变压器与平面芯片结构，还通过基板冷却的变压器，温度低于常规，大型铝板结构的可用输出功率相同大小的变压器。铝板跳线引桥都可以使用。铝基板电源一般由两块PCB，另一个将通过物理连接两块板之间的集成控制电路板，铝基板电源。
由于优良的热导率铝板焊，少量手工焊接更加困难，焊料冷却过快，过去简单实用的方法对现有的熨烫普通铁（最好的温度调节功能）容易出现问题的存在。最后，使温度，加热时间至150℃以上的铁铝板上稳定，然后固定上的组件按常规
方法焊接，电烙铁温度适当的设备容易焊接，过高时该设备可能会损坏，甚至铜带铝板，温度太低焊接效果并不好，要灵活。
近年来，随着多层电路板应用在电源电路开关电源，印刷电路变压器使它成为可能，由于多层，小间距也可以部分利用Bianya齐窗口，主电路板可重新添加一良好的耦合-2所形成的多层印刷线圈使用视窗电路1-2形成由多层印刷线圈使用的窗口，减少电流密度的目的，由于采用印刷线圈，减少人工干预，变压器的一致性，表面结构，低漏感。开放型磁芯，散热性好。因为它具有很多优点，有利于大规模生产，它被广泛使用。但研究与初始投资大，不适合进行小规模的健康发展。
开关电源分为两个独立形式的隔离和非孤立的隔离，这里主要谈谈开关电源拓扑结构形式下，非指定的隔离电源。供应隔离电源按照不同的结构形式可分为两类：正激和反激。反激变压器初级端意味着当Vice-edge导通截止，变压器存储。关闭的初级，中级侧传导，释放的能量功率反激式多路给负载的工作状态，一般传统反激式电源复用，负荷释放的能量的双管并不常见。而相应的输出电压诱导的负载，能量通过变压器的直接转移到转发是指在变压器二次侧主的传导。按规格可分为常规推进，包括单管正激，双管正激。半桥，全桥电路是正激电路
正激和反激电路具有电路设计他们自己的进程的特点，在达到最佳的成本效益，能灵活运用。反激式通常是低功率可以被采纳。稍大正激电路可以使用单管，中等功率可以使用双管正激电路或半桥电路，推挽电路，可应用于高功率输出，一般用于电桥电路，低电压。高功率输出，一般用于电桥电路，低电压可应用于推挽电路。
反激式电源供应器，因为它结构简单，并减少电感的大小，同样的变压器，电源供应器中的介质已被广泛应用。实验中提到的一些反激式电源供应器可以做到几十瓦，输出功率超过100瓦的优势将不会对他们很难。在正常情况下，我认为是这样，但不能一概而论，，PI的芯片可以做到300瓦，文章介绍了反激式电源，可对千瓦，但没见过实物。
输出功率和输出电压水平。
反激式电源变压器的漏感是一个关键参数，因为电源，反激变压器需要储存的能量，使变压器磁芯充分利用，一般必须打开磁路空隙，其目的是改变核心迟滞后线的斜率，使变压器能承受大型脉冲电流的状态影响，这是不饱和非线性状态的核心，在漏磁场中生成高磁阻气隙中的磁路是完全闭合磁路比大得多。
第一极是变压器之间的耦合的一个关键因素的确定泄漏电感、线圈尽可能非常近的第一时间,可以使用的夹心阶层,但这无疑会增加变压器的分布电容。使用Core核心，以及长窗，可以有效降低漏感，例如对EE的用途， EF， EER，基于PQ的EI类型磁芯有效。
反激式电源的占空比，原则上，反激式电源的最大占空比应小于0.5，否则不容易的环路补偿可能是不稳定的，但也有一些例外的TOP系列，如美国的PI 推出芯片可以工作在占空比大于0.5条件下。
务变周期的圈数比，以确定原副边匝数比，我的抗冲击的看法是，首先确定反射电压（输出电压值反映通过变压器耦合的初级电压），反映了一定的电压增加电压范围为占空比的增加，较低的功率损耗。降低反射电压占空比减小，提高了功率损耗。当然，这是一个先决条件，当占空比增大，这意味着输出二极管导通时间，以保持输出稳定，更多的时间将是保证输出电容放电电流，输出电容将受到
更大的高频纹波电流的侵蚀，同时增加它的热量，这在很多情况下是不允许的。
占空比增大，改变变压器匝数比，变压器漏感会增加，其整体性能的变化，当漏感能量足够大时，可以切换到完全抵消大容量空间，使损耗低，没有进一步上升的含义责任，因为漏感，甚至可能过于对峰值开关高电压击穿大量泄漏电感一样，可能使输出纹波和其他电磁指标恶化。当值小时，RMS和高RMS电流通过开关，变压器初级电流转换器的效率降低，但可以提高，以减少发热的工作条件的输出电容。如何确定变压器反射电压（占空比）
那么今天，在反激式电源（我关心的反射电压工作周期的一致性）的占空比，选择开关占空比的电压是与一些早期的反激式开关电源采用低压管，如600V或650V的交流220V输入功率开关一样，或许当生产过程中，高压管，容易制造，或低压管道更合理的传导损耗和开关特性，因为这条线反映的电压不能太高，否则工作以吸收电路安全开关电源方面的损失是相当可观的。
反射电压600V的管证明不超过100V的，650V的管反射电压不大于120伏，漏感尖峰电压时，管50V的钳位在50V的工作边缘。现在，MOS提高生产过程控制水平，反激式电源供应器通常用于700V的或750V或800 - 900V的开关。像这样的电路，开关变压器过电压能力，对数字反射电压可以做高一点，最大反射电压在150V的是适当的，以获得更好的整体性能。
首页PI的建议的二极管钳位135V芯片组，瞬态电压抑制。但他的评估板普遍反映电压，价值低于110伏特左右。这两种类型都有其优点和缺点：
分类：循环缺点防止过电压，低占空比小，大电流脉冲变压器的初级。优点：小型变压器漏感，电磁辐射和低纹波指数较高的开关损耗，转换效率不低于一定秒。第二类：缺点，大量的功率损失，大量的变压器漏感，纹波差。
优势：有较高的强烈反对过电压，大占空比，降低变压器损耗和效率。
反射电压反激式电源和一个决定性因素。
反射电压反激式电源供应的消费能力与吸收相关的参数是输出电压，输出电压，降低变压器的匝比越大，更大的变压器漏感，切换到承受高电压击穿开关可能较高，有可能永久地吸收电路的电源设备出现故障（特别是瞬态电压抑制二极管电路）。在这个过程中设计的低电压低功率返驰式电源输出最优化，必须小心处理与，其方法有几个：
1，采用大芯一般的功率水平较低的泄漏电感，可以提高低电压反激式电源转换效率，降低损耗，降低输出纹波，提高多调节输出功率，是两岸共同的家庭电器与一开关电源，如CD - ROM驱动器的DVB机顶盒。
2，如果条件不增加核心，可降低反射电压，降低占空比。降低反射电压可降低漏感，但可降低功率转换效率，这是一个两之间的矛盾，必须有一个替代过程，找到一个合适的点，更换变压器试验过程中可以检测到变压器原边反峰电压，峰值电压，以减少反脉冲宽度，大小和转换器的工作安全系数增加。普遍反映电压110V在适当的时候。
3，增强耦合，减少损失，引进新的技术和路由过程，变压器，以满足安全规范将小学和中学之间的边带保温措施，如垫带，再加上侧空气绝缘。这些都会影响性能的电感变压器漏，现实的，可用于生产各地的初级绕组二次包装的方法。或分线制与三重绝缘伤口，除去初始水平之间的绝缘层，可以提高耦合，甚至使用广泛的铜线圈。
文章指的是低电压输出小于或等于5V输出，这个供应类型的小功率，我的经验是，20W的输出功率输出超过可使用正激，得到物有所值的最佳过程中，这是
不正确的决定，个人习惯，环境之间的关系应用，下一次谈论一个磁芯与反激式电源供应器，磁路气隙开放一些了解，我希望你得到足够的指导。
反激式电源变压器磁芯磁化在开展的工作之一，它需要开放磁路气隙，类似的脉动直流电流传感器。部分气隙磁耦合通过。我理解的开放气隙原则如下：由于功率铁氧体饱和度也有一个过程类似矩形的经营特色（滞后环），工作特性曲线的Y轴磁感应强度（乙），现在一般生产这在400mT值点以上的设计中，一般价值应比较合适，在200 -300吨，X轴磁场强度（H）的强度值成正比的电流磁化。开磁路气隙等于磁滞回线的X轴的倾斜力度，在相同的磁感应强度，能承受较大的励磁电流，相当于核心储存更多的能量，这种能量切断开关当负载溅入通过变压器次级电路，反激式电源的核心打开空气间隙是双重的。一个是传输更多的能量，第二，防止陷入饱和的核心。
反激式电源变压器磁化状态的一种方式，不仅要通过磁耦合能量，也是负责电压输入和输出隔离转换多个角色。因此，焊接缺口需要非常小心，空气间隙漏感会变得太大，磁滞损耗增加，铁损，铜损增加，影响了整体表现力。空气间隙过小有可能变压器磁芯饱和，导致电源损坏。
所谓的反激式电源变压器的连续和不连续模式工作条件，工作方式完成电力变压器在满负荷条件下的转移，或不完整的传输。一般的工作环境设计，传统的反激式电源供应器应工作在连续模式下，此开关，电路损失都比较小，并能减少电容器的工作压力输入和输出，但有一些例外。
在需要特别指出：随着电力供应的特点，反激也比较适合设计成一个高压电源，高压电源变压器，一般工作在连续模式下，我需要了解电源输出电压为高功率电压的整流二极管。由于制造工艺的特点，高压二极管，反向恢复时间长，低转速，电流连续状态下，二极管的正向偏置的恢复，反向恢复能量损失非常大，不利于转换器的性能增加，发热，从降低转换效率，整流器，严重，重则甚至烧毁整流器。如间歇模式，二极管是反向偏置在零偏置，损耗可降低到较低的水平。因此，高电压电源供应工作在非连续模式，频率不能太高。
另一种类型的临界状态，在FM电力供应工作，或调频调宽双模式的通用型反激式电源供应工作，一些低成本的自激电源（RCC）是经常使用这种形式为了确保稳定的输出变压器的工作频率，输出电流或输入电压的变化，接近满载的变压器始终保持在连续和间歇性之间，这种力量是只适合小功率输出，否则电磁处理的特点兼容性将是一个头痛问题
反激式开关电源变压器应工作在连续模式下，它需要比较大的绕组电感，当然，是在一定程度上连续的，过分追求的绝对连续性是不现实的，可能需要一个巨大的核心，非常多的线圈匝数，一个伴随着大的漏感和分布电容，很麻烦。如何来确定这个参数，经过反复实践，和同行的设计分析，我认为，在额定电压输入，输出达到50％和60％的变压器从间歇，连续状态过渡到更合适。或在最高输入电压状态，完整的输出，变压器可以过渡到连续状态就可以了
外文出处： 《Exploiting Software How to Break Code》By Greg Hoglund, Gary McGraw Publisher : Addison Wesley Pub Date : February 17, 2004 ISBN : 0-201-78695-8 译文标题： JDBC接口技术 译文： JDBC是一种可用于执行SQL语句的JavaAPI（ApplicationProgrammingInterface应用程序设计接口）。它由一些Java语言编写的类和界面组成。JDBC为数据库应用开发人员、数据库前台工具开发人员提供了一种标准的应用程序设计接口，使开发人员可以用纯Java语言编写完整的数据库应用程序。 一、ODBC到JDBC的发展历程 说到JDBC，很容易让人联想到另一个十分熟悉的字眼“ODBC”。它们之间有没有联系呢？如果有，那么它们之间又是怎样的关系呢？ ODBC是OpenDatabaseConnectivity的英文简写。它是一种用来在相关或不相关的数据库管理系统（DBMS）中存取数据的，用C语言实现的，标准应用程序数据接口。通过ODBCAPI，应用程序可以存取保存在多种不同数据库管理系统（DBMS）中的数据，而不论每个DBMS使用了何种数据存储格式和编程接口。 1．ODBC的结构模型 ODBC的结构包括四个主要部分：应用程序接口、驱动器管理器、数据库驱动器和数据源。应用程序接口：屏蔽不同的ODBC数据库驱动器之间函数调用的差别，为用户提供统一的SQL编程接口。 驱动器管理器：为应用程序装载数据库驱动器。 数据库驱动器：实现ODBC的函数调用，提供对特定数据源的SQL请求。如果需要，数据库驱动器将修改应用程序的请求，使得请求符合相关的DBMS所支持的文法。 数据源：由用户想要存取的数据以及与它相关的操作系统、DBMS和用于访问DBMS的网络平台组成。 虽然ODBC驱动器管理器的主要目的是加载数据库驱动器，以便ODBC函数调用，但是数据库驱动器本身也执行ODBC函数调用，并与数据库相互配合。因此当应用系统发出调用与数据源进行连接时，数据库驱动器能管理通信协议。当建立起与数据源的连接时，数据库驱动器便能处理应用系统向DBMS发出的请求，对分析或发自数据源的设计进行必要的翻译，并将结果返回给应用系统。 2．JDBC的诞生 自从Java语言于1995年5月正式公布以来，Java风靡全球。出现大量的用java语言编写的程序，其中也包括数据库应用程序。由于没有一个Java语言的API，编程人员不得不在Java程序中加入C语言的ODBC函数调用。这就使很多Java的优秀特性无法充分发挥，比如平台无关性、面向对象特性等。随着越来越多的编程人员对Java语言的日益喜爱，越来越多的公司在Java程序开发上投入的精力日益增加，对java语言接口的访问数据库的API 的要求越来越强烈。也由于ODBC的有其不足之处，比如它并不容易使用，没有面向对象的特性等等，SUN公司决定开发一Java语言为接口的数据库应用程序开发接口。在JDK1．x 版本中，JDBC只是一个可选部件，到了JDK1．1公布时，SQL类包（也就是JDBCAPI）
Circuit breaker 断路器 Compressed air circuit breaker is a mechanical switch equipm ent, can be i 空气压缩断路器是一种机械开关设备，能够在n normal and special conditions breaking current (such as sho rt circuit cur 正常和特殊情况下开断电流（比如说短路电流）。 rent). For example, air circuit breaker, oil circuit breaker, interf erence circ 例如空气断路器、油断路器，干扰电路的导体uit conductor for the application of the safety and reliability o f the circuit 干扰电路的导体因该安全可靠的应用于其中， breaker, current in arc from is usually divided into the followin g grades: a 电流断路器按灭弧远离通常被分为如下等级：ir switch circuit breaker, oil circuit breaker, less oil circuit break er, compr 空气开关断路器、油断路器、少油断路器、压缩空essed air circuit breaker, a degaussing of isolating switch, six s ulfur hexaf
本科毕业设计 外文文献及译文 文献、资料题目：Designing Against Fire Of Building 文献、资料来源：国道数据库 文献、资料发表（出版）日期：2008.3.25 院（部）：土木工程学院 专业：土木工程 班级：土木辅修091 姓名：武建伟 学号：2008121008 指导教师：周学军、李相云 翻译日期： 20012.6.1
外文文献: Designing Against Fire Of Buliding John Lynch ABSTRACT: This paper considers the design of buildings for fire safety. It is found that fire and the associ- ated effects on buildings is significantly different to other forms of loading such as gravity live loads, wind and earthquakes and their respective effects on the building structure. Fire events are derived from the human activities within buildings or from the malfunction of mechanical and electrical equipment provided within buildings to achieve a serviceable environment. It is therefore possible to directly influence the rate of fire starts within buildings by changing human behaviour, improved maintenance and improved design of mechanical and electrical systems. Furthermore, should a fire develops, it is possible to directly influence the resulting fire severity by the incorporation of fire safety systems such as sprinklers and to provide measures within the building to enable safer egress from the building. The ability to influence the rate of fire starts and the resulting fire severity is unique to the consideration of fire within buildings since other loads such as wind and earthquakes are directly a function of nature. The possible approaches for designing a building for fire safety are presented using an example of a multi-storey building constructed over a railway line. The design of both the transfer structure supporting the building over the railway and the levels above the transfer structure are considered in the context of current regulatory requirements. The principles and assumptions associ- ated with various approaches are discussed. 1 INTRODUCTION Other papers presented in this series consider the design of buildings for gravity loads, wind and earthquakes.The design of buildings against such load effects is to a large extent covered by engineering based standards referenced by the building regulations. This is not the case, to nearly the same extent, in the
附录1：外文资料翻译 A1.1外文资料题目 26.22 接地故障电路开关 我们目前为止报道的接地方法通常是充分的, 但更加进一步的安全措施在某些情况下是必要的。假设例如, 有人将他的手指伸进灯口（如Fig.26.45示）。虽然金属封入物安全地接地, 但那人仍将受到痛苦的震动。或假设1个120V 的电炉掉入游泳池。发热设备和联络装置将导致电流流入在水池中的危害，即使电路的外壳被安全地接地，现在已经发展为当这样的事件发生时，设备的电源将被切断。如果接地电流超过5mA ，接地开关将在5 ms 内跳掉，这些装置怎么运行的？ 如Fig.26.46所示，一台小变流器缠绕上导线 ，第二步是要连接到可能触发开合120 V 线的一台敏感电子探测器。 在正常情况下流过导体的电流W I 与中性点上的电流N I 准切的相等，因此流经核心的净潮流(N W I I -)是零。 结果，在核心没有产生电流，导致的电压F E 为零，并且开关CB 没有动作。 假设如果某人接触了一个终端(图Fig.26.45示)，故障电流F I 将直接地从载电线漏到地面，这是可能发生的。如果绝缘材料在马达和它的地面封入物之间断开，故障电流也会被产生。在以下任何情况下，流经CT 的孔的净潮流等于F I 或L I ，不再是零。电流被产生，并且产生了可以控制CB 开关的电压F E 。 由于5 mA 不平衡状态只必须被检测出，变压器的核心一定是非常有渗透性的在低通量密度。 Supermalloy 是最为常用的，因为它有相对渗透性典型地70000在通量密度仅4mT 。 26.23 t I 2是导体迅速发热的因素 它有时发生于导体短期内电流远大于正常值的情况下，R I 2损失非常大并且导体的温度可以在数秒内上升几百度。例如，当发生严重短路时，在保险丝或开关作用之前，会有很大的电流流过导体和电缆。 此外，热量没有时间被消散到周围，因此导体的温度非常迅速地增加。 在这些情况下什么是温度上升？ 假设导体有大量m ，电阻R 和热量热容量c 。 而且，假设电流是I ，并且那它流动在t 少于15秒期间。 在导体上引起的热 Rt I Q 2= 从Eq.3.17，在功率一定的情况下我们可以计算导体上升的温度差：
毕业设计（论文）外文文献翻译 文献、资料中文题目：软件开发概念和设计方法文献、资料英文题目： 文献、资料来源： 文献、资料发表（出版）日期： 院（部）： 专业： 班级： 姓名： 学号： 指导教师： 翻译日期： 2017.02.14
外文资料原文 Software Development Concepts and Design Methodologies During the 1960s, ma inframes and higher level programming languages were applied to man y problems including human resource s yste ms,reservation s yste ms, and manufacturing s yste ms. Computers and software were seen as the cure all for man y bu siness issues were some times applied blindly. S yste ms sometimes failed to solve the problem for which the y were designed for man y reasons including: ?Inability to sufficiently understand complex problems ?Not sufficiently taking into account end-u ser needs, the organizational environ ment, and performance tradeoffs ?Inability to accurately estimate development time and operational costs ?Lack of framework for consistent and regular customer communications At this time, the concept of structured programming, top-down design, stepwise refinement，and modularity e merged. Structured programming is still the most dominant approach to software engineering and is still evo lving. These failures led to the concept of "software engineering" based upon the idea that an engineering-like discipl ine could be applied to software design and develop ment. Software design is a process where the software designer applies techniques and principles to produce a conceptual model that de scribes and defines a solution to a problem. In the beginning, this des ign process has not been well structured and the model does not alwa ys accurately represent the problem of software development. However,design methodologies have been evolving to accommo date changes in technolog y coupled with our increased understanding of development processes. Whereas early desig n methods addressed specific aspects of the
外文原文 Mechanical Design Abstract: A machine is a combination of mechanisms and other components which transforms, transmits. Examples are engines, turbines, vehicles, hoists, printing presses, washing machines, and movie cameras. Many of the principles and methods of design that apply to machines also apply to manufactured articles that are not true machines. The term "mechanical design" is used in a broader sense than "machine design" to include their design. the motion and structural aspects and the provisions for retention and enclosure are considerations in mechanical design. Applications occur in the field of mechanical engineering, and in other engineering fields as well, all of which require mechanical devices, such as switches, cams, valves, vessels, and mixers. Keywords: Mechanical Design mechanisms Design Process The Design Process Designing starts with a need real.Existing apparatus may need improvements in durability, efficiency, weight, speed, or cost. New apparatus may be needed to perform a function previously done by men, such as computation, assembly, or servicing. With the objective wholly or partly In the design preliminary stage, should allow to design the personnel fully to display the creativity, not each kind of restraint. Even if has had many impractical ideas, also can in the design early time, namely in front of the plan blueprint is corrected. Only then, only then does not send to stops up the innovation the mentality. Usually, must propose several sets of design proposals, then perform the comparison. Has the possibility very much in the plan which finally designated, has used certain not in plan some ideas which accepts. When the general shape and a few dimensions of the several components become
外文翻译 专业机械设计制造及其自动化学生姓名刘链柱 班级机制111 学号1110101102 指导教师葛友华
外文资料名称： Design and performance evaluation of vacuum cleaners using cyclone technology 外文资料出处：Korean J. Chem. Eng., 23(6), (用外文写) 925-930 (2006) 附件： 1.外文资料翻译译文 2.外文原文
应用旋风技术真空吸尘器的设计和性能介绍 吉尔泰金，洪城铱昌，宰瑾李， 刘链柱译 摘要：旋风型分离器技术用于真空吸尘器 - 轴向进流旋风和切向进气道流旋风有效地收集粉尘和降低压力降已被实验研究。优化设计等因素作为集尘效率，压降，并切成尺寸被粒度对应于分级收集的50％的效率进行了研究。颗粒切成大小降低入口面积，体直径，减小涡取景器直径的旋风。切向入口的双流量气旋具有良好的性能考虑的350毫米汞柱的低压降和为1.5μm的质量中位直径在1米3的流量的截止尺寸。一使用切向入口的双流量旋风吸尘器示出了势是一种有效的方法，用于收集在家庭中产生的粉尘。 摘要及关键词：吸尘器; 粉尘; 旋风分离器 引言 我们这个时代的很大一部分都花在了房子，工作场所，或其他建筑，因此，室内空间应该是既舒适情绪和卫生。但室内空气中含有超过室外空气因气密性的二次污染物，毒物，食品气味。这是通过使用产生在建筑中的新材料和设备。真空吸尘器为代表的家电去除有害物质从地板到地毯所用的商用真空吸尘器房子由纸过滤，预过滤器和排气过滤器通过洁净的空气排放到大气中。虽然真空吸尘器是方便在使用中，吸入压力下降说唱空转成比例地清洗的时间，以及纸过滤器也应定期更换，由于压力下降，气味和细菌通过纸过滤器内的残留粉尘。 图1示出了大气气溶胶的粒度分布通常是双峰形，在粗颗粒（>2.0微米）模式为主要的外部来源，如风吹尘，海盐喷雾，火山，从工厂直接排放和车辆废气排放，以及那些在细颗粒模式包括燃烧或光化学反应。表1显示模式，典型的大气航空的直径和质量浓度溶胶被许多研究者测量。精细模式在0.18?0.36 在5.7到25微米尺寸范围微米尺寸范围。质量浓度为2?205微克，可直接在大气气溶胶和 3.85至36.3μg/m3柴油气溶胶。
专业资料 学院： 专业：土木工程 姓名： 学号： 外文出处：Structural Systems to resist (用外文写) Lateral loads 附件：1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文 抗侧向荷载的结构体系 常用的结构体系 若已测出荷载量达数千万磅重，那么在高层建筑设计中就没有多少可以进行极其复杂的构思余地了。确实，较好的高层建筑普遍具有构思简单、表现明晰的特点。 这并不是说没有进行宏观构思的余地。实际上，正是因为有了这种宏观的构思，新奇的高层建筑体系才得以发展，可能更重要的是：几年以前才出现的一些新概念在今天的技术中已经变得平常了。 如果忽略一些与建筑材料密切相关的概念不谈，高层建筑里最为常用的结构体系便可分为如下几类： 1.抗弯矩框架。 2.支撑框架，包括偏心支撑框架。 3.剪力墙，包括钢板剪力墙。 4.筒中框架。 5.筒中筒结构。 6.核心交互结构。 7. 框格体系或束筒体系。 特别是由于最近趋向于更复杂的建筑形式，同时也需要增加刚度以抵抗几力和地震力，大多数高层建筑都具有由框架、支撑构架、剪力墙和相关体系相结合而构成的体系。而且，就较高的建筑物而言，大多数都是由交互式构件组成三维陈列。 将这些构件结合起来的方法正是高层建筑设计方法的本质。其结合方式需要在考虑环境、功能和费用后再发展，以便提供促使建筑发展达到新高度的有效结构。这并
不是说富于想象力的结构设计就能够创造出伟大建筑。正相反，有许多例优美的建筑仅得到结构工程师适当的支持就被创造出来了，然而，如果没有天赋甚厚的建筑师的创造力的指导，那么，得以发展的就只能是好的结构，并非是伟大的建筑。无论如何，要想创造出高层建筑真正非凡的设计，两者都需要最好的。 虽然在文献中通常可以见到有关这七种体系的全面性讨论，但是在这里还值得进一步讨论。设计方法的本质贯穿于整个讨论。设计方法的本质贯穿于整个讨论中。 抗弯矩框架 抗弯矩框架也许是低，中高度的建筑中常用的体系，它具有线性水平构件和垂直构件在接头处基本刚接之特点。这种框架用作独立的体系，或者和其他体系结合起来使用，以便提供所需要水平荷载抵抗力。对于较高的高层建筑，可能会发现该本系不宜作为独立体系，这是因为在侧向力的作用下难以调动足够的刚度。 我们可以利用STRESS，STRUDL 或者其他大量合适的计算机程序进行结构分析。所谓的门架法分析或悬臂法分析在当今的技术中无一席之地，由于柱梁节点固有柔性，并且由于初步设计应该力求突出体系的弱点，所以在初析中使用框架的中心距尺寸设计是司空惯的。当然，在设计的后期阶段，实际地评价结点的变形很有必要。 支撑框架 支撑框架实际上刚度比抗弯矩框架强，在高层建筑中也得到更广泛的应用。这种体系以其结点处铰接或则接的线性水平构件、垂直构件和斜撑构件而具特色，它通常与其他体系共同用于较高的建筑，并且作为一种独立的体系用在低、中高度的建筑中。
中文翻译 STC89C52处理芯片 电气工程的研究和解决方案中心（ceers） 艾哈迈德为吉.波特 首要性能： 与MCS-51单片机产物兼容、8K字节在系统可编程视频存储器、1000次擦拭周期，全静态操作：0Hz~33Hz、三级加密程序存储器，32个可编程I/O接口线、三个16位定时器（计数器），八个中断源、低功能耗空闲和掉电模式、掉电后间断可唤醒，看门狗定时器、双数值指针，掉电标示符。 关键词：单片机，UART串行通道，掉电标示符等 前言 可以说，二十世纪跨越了三个“点”的时代，即电气时代，电子时代和现已进入的电脑时代。不过，这种电脑，通常指的是个人计算机，简称PC机。还有就是把智能赋予各种机械的单片机（亦称微控制器）。顾名思义，这种计算机的最小系统只用了一片集成电路，即可进行简单的运算可控制。因为它体积小，通常都是藏在被控机械的内部里面。它在整个装置中，起着有如人类头脑的作用，他出了毛病，整个装置就会瘫痪。现在，单片机的种类和适用领域已经十分广泛，如智能仪表、实施工控、通讯设备、导航系统、家用电器等。各种产品一旦用上了单片机，就你能起到产品升级换代的功效，常在产品名称前冠以形容词——“智能型”，如智能洗衣机等。接下来就是关于国产STC89C52单片机的一些基本参数。 功能特性描述: STC89C52单片机是一种低功耗、高性能CMOS8位微控制器，具有8K在系统可编程视频播放存贮器使用高密度非易失性存储器技术制造，与工业80C51 产物指令和引脚完全兼容。片上反射速度允许程序存储器在系统可编程，也适用于常规的程序编写器。在其单芯片上，拥有灵敏小巧的八位中央处理器和在线系统可编程反射，这些使用上STC89C52微控制器为众多嵌入式的控制应用系统提供高度矫捷的、更加有用的解决方案。STC89C52微控制器具有以下的标准功效：8K字节的反射速度，256字节的随机存取储存器，32位I/O串口线，看门狗定时器，2个数值指针，三个16 为定时器、计数器，一个6向量2级间断结构，片内晶振及钟表电路。另外，STC89C52可降至0HZ静态逻辑操作，支持两种软件可选择节电模式、间断继续工作。空闲模式下，CPU停止工作，允许RAM、定时器/计数器、串口、间断继续工作。掉电保护体式格局下，RAM内容被生成，振动器被冻结，单片机一切的工作停止，直到下一个间断或者硬件复位为止。8位微型控制器8K字节在系统中可编程FlashSTC89C52.。
I / 11 本科毕业设计外文翻译 <2018届） 论文题目基于WEB 的J2EE 的信息系统的方法研究 作者姓名[单击此处输入姓名] 指导教师[单击此处输入姓名] 学科(专业 > 所在学院计算机科学与技术学院 提交日期[时间 ]
基于WEB的J2EE的信息系统的方法研究 摘要：本文介绍基于工程的Java开发框架背后的概念，并介绍它如何用于IT 工程开发。因为有许多相同设计和开发工作在不同的方式下重复，而且并不总是符合最佳实践，所以许多开发框架建立了。我们已经定义了共同关注的问题和应用模式，代表有效解决办法的工具。开发框架提供：<1）从用户界面到数据集成的应用程序开发堆栈；<2）一个架构，基本环境及他们的相关技术，这些技术用来使用其他一些框架。架构定义了一个开发方法，其目的是协助客户开发工程。 关键词：J2EE 框架WEB开发 一、引言 软件工具包用来进行复杂的空间动态系统的非线性分析越来越多地使用基于Web的网络平台，以实现他们的用户界面，科学分析，分布仿真结果和科学家之间的信息交流。对于许多应用系统基于Web访问的非线性分析模拟软件成为一个重要组成部分。网络硬件和软件方面的密集技术变革[1]提供了比过去更多的自由选择机会[2]。因此，WEB平台的合理选择和发展对整个地区的非线性分析及其众多的应用程序具有越来越重要的意义。现阶段的WEB发展的特点是出现了大量的开源框架。框架将Web开发提到一个更高的水平，使基本功能的重复使用成为可能和从而提高了开发的生产力。 在某些情况下，开源框架没有提供常见问题的一个解决方案。出于这个原因，开发在开源框架的基础上建立自己的工程发展框架。本文旨在描述是一个基于Java的框架，该框架利用了开源框架并有助于开发基于Web的应用。通过分析现有的开源框架，本文提出了新的架构，基本环境及他们用来提高和利用其他一些框架的相关技术。架构定义了自己开发方法，其目的是协助客户开发和事例工程。 应用程序设计应该关注在工程中的重复利用。即使有独特的功能要求，也
1、 外文原文 A: Fundamentals of Single-chip Microcomputer Th e si ng le -c hi p m ic ro co mp ut er i s t he c ul mi na ti on of both t h e de ve lo pm en t o f t he d ig it al co m pu te r an d th e i n te gr at ed c i rc ui t a rg ua bl y t h e to w m os t s ig ni f ic an t i nv en ti on s o f t he 20th c e nt ur y [1]. Th es e t ow ty pe s of ar ch it ec tu re a re fo un d i n s in g le -ch i p m i cr oc om pu te r. So m e em pl oy t he spl i t pr og ra m/da ta m e mo ry o f th e H a rv ar d ar ch it ect u re , sh ow n in Fi g.3-5A -1, o th ers fo ll ow t he p h il os op hy , wi del y a da pt ed f or ge n er al -p ur po se co m pu te rs a nd m i cr op ro ce ss o r s, o f ma ki ng n o log i ca l di st in ct ion be tw ee n p r og ra m an d d at a m e mo ry a s i n t he P r in ce to n ar ch ite c tu re , sh ow n i n F ig.3-5A-2. In g en er al te r ms a s in gl e -chi p m ic ro co mp ut er i s c h ar ac te ri ze d b y t h e i nc or po ra ti on o f a ll t he un it s of a co mp uter i n to a s in gl e d ev i ce , as s ho wn in Fi g3-5A -3. Fig.3-5A-1 A Harvard type Program memory Data memory CPU Input& Output unit memory CPU Input& Output unit
毕业设计（论文） 外文翻译 题目西安市水源工程中的 水电站设计 专业水利水电工程 班级 学生 指导教师 2016年
研究钢弧形闸门的动态稳定性 牛志国 河海大学水利水电工程学院，中国南京，邮编210098 nzg_197901@https://www.doczj.com/doc/ad985351.html,，niuzhiguo@https://www.doczj.com/doc/ad985351.html, 李同春 河海大学水利水电工程学院，中国南京，邮编210098 ltchhu@https://www.doczj.com/doc/ad985351.html, 摘要 由于钢弧形闸门的结构特征和弹力，调查对参数共振的弧形闸门的臂一直是研究领域的热点话题弧形弧形闸门的动力稳定性。在这个论文中，简化空间框架作为分析模型，根据弹性体薄壁结构的扰动方程和梁单元模型和薄壁结构的梁单元模型，动态不稳定区域的弧形闸门可以通过有限元的方法，应用有限元的方法计算动态不稳定性的主要区域的弧形弧形闸门工作。此外，结合物理和数值模型，对识别新方法的参数共振钢弧形闸门提出了调查，本文不仅是重要的改进弧形闸门的参数振动的计算方法，但也为进一步研究弧形弧形闸门结构的动态稳定性打下了坚实的基础。 简介 低举升力，没有门槽，好流型，和操作方便等优点，使钢弧形闸门已经广泛应用于水工建筑物。弧形闸门的结构特点是液压完全作用于弧形闸门，通过门叶和主大梁，所以弧形闸门臂是主要的组件确保弧形闸门安全操作。如果周期性轴向载荷作用于手臂，手臂的不稳定是在一定条件下可能发生。调查指出:在弧形闸门的20次事故中，除了极特殊的破坏情况下，弧形闸门的破坏的原因是弧形闸门臂的不稳定;此外，明显的动态作用下发生破坏。例如:张山闸，位于中国的江苏省，包括36个弧形闸门。当一个弧形闸门打开放水时，门被破坏了，而其他弧形闸门则关闭，受到静态静水压力仍然是一样的，很明显，一个动态的加载是造成的弧形闸门破坏一个主要因素。因此弧形闸门臂的动态不稳定是造成弧形闸门(特别是低水头的弧形闸门)破坏的主要原是毫无疑问。
PA VEMENT PROBLEMS CAUSED BY COLLAPSIBLE SUBGRADES By Sandra L. Houston,1 Associate Member, ASCE (Reviewed by the Highway Division) ABSTRACT: Problem subgrade materials consisting of collapsible soils are com- mon in arid environments, which have climatic conditions and depositional and weathering processes favorable to their formation. Included herein is a discussion of predictive techniques that use commonly available laboratory equipment and testing methods for obtaining reliable estimates of the volume change for these problem soils. A method for predicting relevant stresses and corresponding collapse strains for typical pavement subgrades is presented. Relatively simple methods of evaluating potential volume change, based on results of familiar laboratory tests, are used. INTRODUCTION When a soil is given free access to water, it may decrease in volume, increase in volume, or do nothing. A soil that increases in volume is called a swelling or expansive soil, and a soil that decreases in volume is called a collapsible soil. The amount of volume change that occurs depends on the soil type and structure, the initial soil density, the imposed stress state, and the degree and extent of wetting. Subgrade materials comprised of soils that change volume upon wetting have caused distress to highways since the be- ginning of the professional practice and have cost many millions of dollars in roadway repairs. The prediction of the volume changes that may occur in the field is the first step in making an economic decision for dealing with these problem subgrade materials. Each project will have different design considerations, economic con- straints, and risk factors that will have to be taken into account. However, with a reliable method for making volume change predictions, the best design relative to the subgrade soils becomes a matter of economic comparison, and a much more rational design approach may be made. For example, typical techniques for dealing with expansive clays include: (1) In situ treatments with substances such as lime, cement, or fly-ash; (2) seepage barriers and/ or drainage systems; or (3) a computing of the serviceability loss and a mod- ification of the design to "accept" the anticipated expansion. In order to make the most economical decision, the amount of volume change (especially non- uniform volume change) must be accurately estimated, and the degree of road roughness evaluated from these data. Similarly, alternative design techniques are available for any roadway problem. The emphasis here will be placed on presenting economical and simple methods for: (1) Determining whether the subgrade materials are collapsible; and (2) estimating the amount of volume change that is likely to occur in the 'Asst. Prof., Ctr. for Advanced Res. in Transp., Arizona State Univ., Tempe, AZ 85287. Note. Discussion open until April 1, 1989. To extend the closing date one month,
外文文献： The Intelligent Building One of the benefits of the rapid evolution of information technology has been the development of systems that can measure, evaluate, and respond to change。An enhanced ability to control change has sparked developments in the way we design our physical environment, in particular, the buildings in which we work。As a result, we are witnessing significant growth in the area of "Intelligent Buildings"--buildings that incorporate information technology and communication systems, making them more comfortable, secure, productive, and cost-effective What is an Intelligent Building? An Intelligent Building is one equipped with the telecommunications infrastructure that enables it to continuously respond and adapt to changing conditions, allowing for a more efficient use of resources and increasing the comfort and security of its occupants。An Intelligent Building provides these benefits through automated control systems such as: heating, ventilation, and air-conditioning (HVAC)；fire safety；security；and energy/lighting management。For example, in the case of a fire, the fire alarm communicates with the security system to unlock the doors。The security system communicates with the HVAC system to regulate the flow of air to prevent the fire from spreading。 What benefits do Intelligent Buildings offer their owners and occupants? The introduction in the workplace of computers printers photocopiers, and fax machines has increased indoor pollution。Electrical and telecommunications facilities in office buildings are under pressure to satisfy the demands created by the rapid growth of computer and networking technologies。These factors have a definite impact on productivity. New technology can be used to create Intelligent Buildings that address these problems by providing a healthier, more productive, and less energy-intensive work environment。As these are critical factors for business