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1µF6µF 5µF12Vdielectric-Q+Q +2Q (+r , 0)(-r , 0)(0, +r )OPart II. Free Response10.The electric potential diagram above shows equipotentials for a 2-dimensional region of space.a.At which point—A, B, C, D, or E—would an electron have the highest electric potentialenergy? Briefly explain your answer.b.In which general direction does the electric field point in this diagram? Briefly explain youranswer.c.Based on the equipotentials, draw a sketch on the diagram above of the electric field,including at least five field lines.d.At which point—A, B, C, D, or E—is the magnitude of the electric field the greatest? Brieflyjustify your answer.e. A proton is released from rest at point C. Qualitatively describe the proton’s subsequent:i.direction of motionii.speediii.accelerationf.For the proton in part e, calculate its velocity after having moved through a potentialdifference of 10 V.+q –q 0.01 m0.50 m0.50 m–q +qe Gauss’s Law to determine the magnitude of the electric field between the plates.c.Calculate the electric potential V between the two plates.d.Calculate the capacitance of this capacitor.AP Physics Practice Test: Potential, Capacitance κ=2.00A dielectric of is now inserted between the isolated plates while the same amount of charge Qremains on each plate.e.Calculate the new capacitance of the system with the dielectric between the plates.f.The electric field strength between the plates has (check one): ____ increased____ decreased____ remained the sameg.The electric potential between the plates has (check one): ____ increased____ decreased____ remained the sameh.The energy stored in the capacitor has (check one): ____ increased____ decreased____ remained the samei.How would your answers to f , g, and h change if the dielectric had been inserted while thevoltage supply was still connected to the capacitor? Explain.–Qba +Qc r +E –E c b ac.Calculate the magnitude of the difference in electric potential V between the two spheres.d.Calculate the capacitance of this conducting-sphere system.e.The spheres are discharged, and then connected to a source of electric potential of magnitude2V. Calculate how much Work must be done to fully charge the capacitor under these new conditions.-Q+Q +2Q (+r , 0) (-r , 0) (0, +r ) O9. The correct answer is a . The electric potential, or energy per unit charge, represents the amount ofenergy per unit charge it takes to move a test particle from infinitely far away to a given location. For apoint charge, the absolute potential is calculated using for each charge, and the electricpotential at a given location is simply the sum of the individual potentials for each charge in the vicinity:V =kQrV =V +Q +V +2Q +V −Q∑V =k (+Q )r +k (+2Q )r +k (−Q )r =2kQr. Field lines become more closely spaced there.The proton accelerates in the same direction of field, ie, towards upper left of diagram.The proton has a speed that increases over time; the electric field applies a force to it, causing it to accelerate.The proton’s acceleration increases as it moves into an area with an increasingly strong electricfield.This is a conservation of energy problem, with the field doing Work on the charge to increase its kinetic energy. Here, we can look at the change in electric potential energy and see how that converts to kinetic−Ki =12mv2−0=2(1.60e−19C)(10V)(1.67e−27kg)=4.38e4m/s– +– +–Q ba+Qcr +E –E c b aBecause only the magnitude of the potential was requested, is also acceptable.d. Using the definition of capacitance:Note that capacitance formula must use (b – a ) in denominator to produce positive result, because capacitance is always positive.e. Potential has doubled, and because Q = VC , the charge on the capacitor has doubled as well.kQ 1a −1b "#$%&'C =Q V =Q kQ 1a −1b #$&'=1k ab b −a "#$%&'U =12QV =122Q ()2kQ ab b −a "#$%&'=2kQ 2ab b −a "#$%&'。
高三环保行动英语阅读理解30题1<背景文章>Environmental issues have become one of the most pressing concerns in the world today. Climate change is a major threat, with rising temperatures leading to melting ice caps, rising sea levels, and more extreme weather events. Pollution is also a significant problem, affecting the air we breathe, the water we drink, and the land we live on.Air pollution is caused by a variety of factors, including industrial emissions, vehicle exhaust, and burning of fossil fuels. This can lead to respiratory problems, heart disease, and even cancer. Water pollution comes from industrial waste, agricultural runoff, and sewage. It can contaminate drinking water sources and harm aquatic life. Land pollution is caused by improper disposal of waste, such as plastic, and can damage soil quality and wildlife habitats.In addition to these problems, deforestation is also a major issue. Trees play a crucial role in absorbing carbon dioxide and producing oxygen. When forests are cut down, it releases large amounts of carbon dioxide into the atmosphere, contributing to climate change.We must take action to address these environmental problems. This can include reducing our carbon footprint by using renewable energysources, reducing waste, and protecting natural habitats. We can also support policies and initiatives that aim to combat climate change and pollution.1. What is one of the major threats caused by climate change?A. Decreasing temperatures.B. Stable sea levels.C. Melting ice caps.D. Less extreme weather events.答案：C。
Energy is a fundamental aspect of modern life,powering our homes,industries,and transportation systems.As the world continues to develop and the population grows,the demand for energy increases,making it crucial to consider sustainable and efficient energy sources.The Importance of EnergyEnergy is vital for the functioning of every aspect of our daily lives.From the moment we wake up and turn on the lights to the moment we go to sleep,energy is omnipresent.It is the driving force behind our economy,enabling industries to manufacture goods,and it is essential for transportation,healthcare,and communication.Types of EnergyThere are various types of energy,including:1.Fossil Fuels:These are nonrenewable energy sources such as coal,oil,and natural gas. They have been the primary source of energy for centuries but contribute significantly to greenhouse gas emissions and climate change.2.Renewable Energy:This includes sources like solar,wind,hydro,geothermal,and biomass.Renewable energy is sustainable and has a lower environmental impact compared to fossil fuels.3.Nuclear Energy:A highdensity energy source that uses nuclear reactions to generate electricity.It is a controversial energy source due to concerns about safety and nuclear waste disposal.Challenges in Energy ProductionThe production of energy,especially from nonrenewable sources,poses several challenges:Environmental Impact:Fossil fuels contribute to air pollution and climate change. Resource Depletion:The finite nature of fossil fuels means they will eventually run out. Economic Costs:The extraction and use of fossil fuels can be expensive and economically volatile.Advantages of Renewable EnergyRenewable energy offers several advantages over traditional energy sources:Sustainability:Renewable energy sources are virtually inexhaustible. Environmental Benefits:They produce little to no greenhouse gas emissions. Economic Opportunities:The renewable energy sector creates jobs and stimulates economic growth.The Future of EnergyThe future of energy lies in innovation and the adoption of cleaner,more efficient technologies.This includes:Improving Energy Efficiency:By making appliances and vehicles more energyefficient, we can reduce overall energy consumption.Expanding Renewable Energy Infrastructure:Investing in solar panels,wind turbines, and hydroelectric plants can help meet the growing energy demand sustainably. Research and Development:Continued research into new energy technologies,such as advanced batteries for energy storage and fusion power,could revolutionize the energy sector.ConclusionAs we move forward,it is imperative that we transition to a more sustainable energy future.This will require a combination of policy changes,technological advancements, and a shift in societal attitudes towards energy consumption.By embracing renewable energy and improving energy efficiency,we can ensure a cleaner,more sustainable world for future generations.。
轨道交通学院毕业设计（论文）外文翻译题目：列车车载的直流恒流源的设计专业电子信息工程班级10115111学号1011511137姓名赵士伟指导教师陈文2014 年3 月 3 日本文摘自：IEEE TRANSACTIONS ON INDUSTRY AND GENERAL APPLICATIONS VOL. IGA-2, NO.5 SEPT/OCT 1966Highly Regulated DC Power Supplies Abstract-The design and application of highly regulated dc power supplies present many subtle, diverse, and interesting problems. This paper discusses some of these problems (especially inconnection with medium power units) but emphasis has been placed more on circuit economics rather than on ultimate performance.Sophisticated methods and problems encountered in connection with precision reference supplies are therefore excluded. The problems discussed include the subjects of temperature coefficient,short-term drift, thermal drift, transient response degeneration caused by remote sensing, and switching preregualtor-type units and some of their performance characteristics.INTRODUCTIONANY SURVEY of the commercial de power supply field will uncover the fact that 0.01 percent regulated power supplies are standard types and can be obtained at relatively low costs. While most users of these power supplies do not require such high regulation, they never-theless get this at little extra cost for the simple reason that it costs the manufacturer very little to give him 0.01 percent instead of 0.1 percent. The performance of a power supply, however, includes other factors besides line and load regulation. This paper will discuss a few of these-namely, temperature coefficient, short-term drift, thermal drift, and transient response. Present medium power dc supplies commonly employ preregulation as a means of improving power/volume ratios and costs, but some characteristics of the power supply suffer by this approach. Some of the short-comings as well as advantages of this technology will be examined.TEMPERATURE COEFFICIENTA decade ago, most commercial power supplies were made to regulation specifications of 0.25 to 1 percent. The reference elements were gas diodes having temperature coefficients of the order of 0.01 percent [1]. Consequently, the TC (temperature coefficient) of the supply was small compared to the regulation specifications and often ignored. Today, the reference element often carries aTC specification greater than the regulation specification.While the latter may be improved considerably at little cost increase, this is not necessarily true of TC. Therefore,the use of very low TC zener diodes, matched differential amplifier stages, and low TC wire wound resistors must be analyzed carefully, if costs are to be kept low.A typical first amplifier stage is shown in Fig. 1. CRI is the reference zener diode and R, is the output adjustment potentiometer.Fig. 1. Input stage of power supply.Fig. 2. Equivalent circuit of zener reference.Let it be assumed that e3, the output of the stage, feedsadditional differential amplifiers, and under steady-state conditions e3 = 0. A variation of any of the parameters could cause the output to drift; while this is also true of the other stages, the effects are reduced by the gain of all previous stages. Consequently, the effects of other stages will be neglected. The following disculssion covers the effects of all elements having primary and secondary influences on the overall TC.Effect of R3The equivalent circuit of CRI -R3 branch is shown in Fig. 2. The zener ha's been replaced with its equivalent voltage source E/' and internal impedance R,. For high gain regulators, the input of the differential amplifier will have negligible change with variations of R3 so thatbefore and after a variation of R3 is made.If it is further assumed that IB << Iz; then from (1)Also,Eliminating I, from (2b),andNow, assuming thatthen,Equation (2b) can also be writtenThe Zener DiodeThe zener diode itself has a temperature coefficient andusually is the component that dominates the overall TCof the unit. For the circuit of Fig. 1, the TC ofthe circuit describes, in essence, the portion of the regulator TC contributed by the zener. If the bridge circuit shown in Fig. 1 were used in conjunction with a dropping resistor so that only a portion of the output voltage appeared across the bridge circuit shown, the TC of the unit and the zener would be different. Since the characteristic of zeners is so well known and so well described in the literature, a discussion will not be given here [2].Variation of Base-Emitter VoltagesNot only do the values of V,, of the differential am-plifier fail to match, but their differentials with tem perature also fail to match. This should not, however,suggest that matched pairs are required. The true reference voltage of Fig. 1 is not the value E,, but E, + (Vie, -Vbe2)-Since, for most practical applicatioinsthe TC of the reference will be the TC of the zener plusConsidering that it is difficult to obtain matched pairs that have differentials as poor as 50 V/°C, it becomes rather apparent that, in most cases, a matched pair bought specifically for TC may be overdesigning.Example 2: A standard available low-cost matched pair laims 30AV/°C. In conjunction with a 1N752, the ontribution to the overall TC would beTests, performed by the author on thirteen standard germanium signal transistors in the vicinity of room temperature and at a collector current level of 3 mA,indicated that it is reasonable to expect that 90 to 95 percent of the units would have a base-emitter voltage variation of -2.1 to -2.4 mV/°C. Spreads of this magnitude have also been verified by others (e.g., Steiger[3]). The worst matching of transistors led to less than 400 ,V/°C differential. In conjunction with a 1N752,even this would give a TC of better than 0.007%/0C.Variation of Base CurrentsThe base current of the transistors is given byA variation of this current causes a variation in signal voltage at the input to the differential amplifier due to finite source impedances. Matching source impedances is not particularly desirable, since it reduces the gain of the system and requires that transistors matched for I,o and A be used. Hunter [4 ] states that the TC of a is in the range of +0.2%/0C to -0.2%7/'C and that 1,, may be approximated bywhere Ao is the value at To.β is also temperature dependent and Steiger [3] experimentally determined the variation to be from about 0.5%/°C to 0.9%/0C.And，Fig. 3. Input circuit of Q2.The current AIB flows through the source impedance per Fig. 3. The drops in the resistance string, however, are subject to the constraint that EB (and AEB) are determined by the zener voltage and the base-emitter drops of Q1 and Q2. Consequently, if in going from temperature T1to T2 a change AEB occurs,The change in output voltage isAndExample 3: For Q2 (at 25°C)(see Example 1)∴Variation of R,The effects of a variation of the TC between RIA and RIB is sufficiently self-evident so that a discussion of the contribution is not included.SHORT-TERM DRIFTThe short-term drift of a supply is defined by the National Electrical Manufacturers Association (NEMA) as "a change in output over a period of time, which change is unrelated to input, environment, or load [5]."Much of the material described in the section on temperature coefficient is applicable here as well. It has been determined experimentally, however, that thermal air drafts in and near thevicinity ofthe powersupplycontributesenormouslyto theshort-termcharacteristics. Thecooling effects of moving air are quite well known, but it is not often recognized that even extremely slow air movements over such devices as zeners and transistors cause the junction temperature of these devices to change rapidly. If the TC of the supply is large compared to the regulation, then large variations in the output will be observed. Units having low TC's achieved by compensation-that is, by canceling out the effects of some omponents by equal and opposite effects of others may still be plagued by these drafts due to the difference in thermal time constants of the elements.Oftentimes, a matched transistor differential amplifier in a common envelope is used for the first amplifier just to equalize and eliminate the difference in cooling effects between the junctions. Approximations to this method include cementing or holding the transistors together, imbedding the transistors in a common metal block, etc. Excellent results were achieved by the author by placing the input stage and zener reference in a separate enclosure. This construction is shown in Fig. 4. The improvement in drift obtained by means of the addition of the metal cover is demonstrated dramatically in Fig. 5.Fig. 5. Short-term drift of a power supply similar to the one shown in Fig. 4 with and without protective covers. The unit was operated without the cover until time tl, when the cover was attached. The initial voltage change following t, is due to a temperaturerise inside the box.Fig. 5. Short-term drift of a power supply similar to the one shown n Fig. 4 withand without protective covers. The unit was operated without the cover until time tl, when the cover was attached. The initial voltage change following t, is due to atemperature rise inside the box.If potentiometers are used in the supply for output adjustment (e.g., RI), care should be used in choosing the value and design. Variations of the contact resistance can cause drift. It is not always necessary, however, to resort to the expense of high-resolution multiturn precision units to obtain low drift. A reduction in range of adjustment, use of low-resistance alloys and low-resolution units which permit the contact arm to rest firmly between turns, may be just as satisfactory. Of course, other considerations should include the ability of both the arms and the wire to resist corrosion. Silicone greases are helpful here. Periodic movement of contact arms has been found helpful in "healing" corroded elements.THERMAL DRIFTNEMA defines thermal drift as "a change in output over a period of time, due to changes in internal ambient temperatures not normally related to environmental changes. Thermal drift is usually associated with changes in line voltage and/or load changes [5]."Thermal drift, therefore, is strongly related to the TC of the supply as well as its overall thermal design. By proper placement of critical components it is possible to greatly reduce or even eliminate the effect entirely. It is not uncommon for supplies of the 0.01 percent(regulation) variety to have drifts of between 0.05 to 0.15 percent for full line or full load variations. In fact, one manufacturer has suggested that anything better than 0.15 percent is good. Solutions to reducing thermal drift other than the obvious approach of improving the TC and reducing internal losses include a mechanical design that sets up a physical and thermal barrier between the critical amplifier components and heat dissipating elements. Exposure to outside surfaces with good ventilation is recommended. With care, 0.01 to 0.05 percent is obtainable.TRANSIENT RESPONSEMost power supplies of the type being discussed have a capacitor across the load terminals. This is used for stabilization purposes and usually determines the dominant time constant of the supply. The presence of this capacitor unfortunately leads to undesirable transient phenomena when the supply is used in the remote sensing mode①. Normally, transistorized power supplies respond in microseconds, but as the author has pointed out [6], the response can degenerate severely in remote sensing .The equivalent circuit is shown in Fig. 6. The leads from the power supply to the load introduce resistance r. Is is the sensing current of the supply and is relatively constant.Under equilibrium conditions,A sudden load change will produce the transient of Fig. 7. The initial "spike" is caused by an inductive surge Ldi/dt; the longer linear discharge following is the resultof the capacitor trying to discharge (or charge). The discharge time iswhereandThe limitations of I,, are usually not due to available drive of the final amplifier stages but to other limitations, current limiting being the most common. Units using pre regulators of the switching type (transistor or SCR types) should be looked at carefully if the characteristics mentioned represent a problem.①Remote sensing is the process by which the power supply senses voltage directly at the load.Fig. 6. Output equivalent circuit at remote sensing.Fig. 7. Transient response, remote sensing.Fig. 8. Block diagram.Preregulated supplies are used to reduce size and losses by monitoring and controlling the voltage across the class-A-type series passing stage (Fig. 8). Since the main regulator invariably responds much quicker than the preregulator, sufficient reserve should always be built into the drop across the passing stage. Failure to provide this may result in saturation of the passing stage when load is applied, resulting in a response time which is that of the preregulator itself.SWITCHING PREREGULATOR-TYPE UNITS The conventional class-A-type transistorized power supply becomes rather bulky, expensive, and crowded with passing stages, as the current and power level of the supply increases. The requirement of wide output adjustment range, coupled with the ability of the supply to be remotely programmable, aggravates the condition enormously. For these reasons the high-efficiency switching regulator has been employed as a preregulator in commercial as well as military supplies for many years. The overwhelming majority of the supplies used silicon controlled rectifiers as the control element. For systems operating from 60-cycle sources, this preregulator responds in 20 to 50 ms.Recent improvements in high-voltage, high-power switching transistors has made the switching transistor pproach more attractive. This system offers a somewhat lower-cost, lower-volume approach coupled with a submillisecond response time. This is brought about by a high switching rate that is normally independent of line frequency. The switching frequency may be fixed, a controlled variable or an independent self-generated (by the LC filter circuit) parameter [7], [8]. Faster response time is highly desirable since it reduces the amount of reserve voltage required across the passing stage or the amount of (storage) capacity required in the preregulator filter.A transistor suitable for operating as a power switch has a high-current, high-voltage rating coupled with low leakage current. Unfortunately, these characteristics are achieved by a sacrifice in thermal capacity, so that simultaneous conditions of voltage and current leading to high peak power could be disastrous. It therefore becomes mandatory to design for sufficient switch drive during peak load conditions and also incorporate current-limiting or rapid overload protection systems.Commercial wide-range power supplies invariably have output current limiting, but this does not limit the preregulator currents except during steady-state load conditions (including short circuits). Consider, for example, a power supply operating at short circuit and the short being removed suddenly. Referring to Fig. 8, the output would rise rapidly, reduce the passing stage voltage, and close the switching transistor. The resulting transient extends over many cycles (switching rate) so that the inductance of the preregulator filter becomes totally inadequate to limit current flow. Therefore, the current will rise until steady state is resumed, circuit resistance causes limiting, or insufficient drive causes the switch to come out of saturation. The latter condition leads to switch failure.Other operating conditions that would produce similar transients include output voltage programming and initial turn-on of the supply. Momentary interruption of input power should also be a prime consideration.One solution to the problem is to limit the rate of change of voltage that can appear across the passing stage to a value that the preregulator can follow. This can be done conveniently by the addition of sufficient output capacitance. This capacitance inconjunction with the current limiting characteristic would produce a maximum rate of change ofwhereC0 = output capacity.Assuming that the preregulator follows this change and has a filter capacitor Cl, then the switch current isDuring power on, the preregulator reference voltage rise must also be limited. Taking this into account,whereER = passing stage voltageTl = time constant of reference supply.The use of SCR's to replace the transistors would be a marked improvement due to higher surge current ratings, but turning them off requires large energy sources. While the gate turn-off SCR seems to offer a good compromise to the overall problem, the severe limitations in current ratings presently restrict their use.REFERENCES[1] J. G. Truxal, Control Engineer's Handbook. New York: McGrawHill, 1958, pp. 11-19.[2] Motorola Zener Diode/Rectifier Handbook, 2nd ed. 1961.[3] W. Steiger, "A transistor temperature analysis and its applica-tion to differential amplifiers," IRE Trans. on Instrumentation,vol. 1-8, pp. 82-91, December 1959.[4] L. P. Hunter, Handbook of Semi-Conductor Electronics. NewYork: McGraw Hill, 1956, p. 13-3.[5] "Standards publication for regulated electronic dc powersupplies," (unpublished draft) Electronic Power Supply Group,Semi-Conductor Power Converter Section, NEMA.[6] P. Muchnick, "Remote sensing of transistorized power sup-plies," Electronic Products, September 1962.[7] R. D. Loucks, "Considerations in the design of switching typeregulators," Solid State Design, April 1963.[8] D. Hancock and B. Kurger, "High efficiency regulated powersupply utilizing high speed switching," presented at the AIEEWinter General Meeting, New York, N. Y., January 27-February 1, 1963.[9] R. D. Middlebrook, Differential Amplifiers. New York: Wiley,1963.[10] Sorensen Controlled Power Catalog and Handbook. Sorensen,Unit of Raytheon Company, South Norwalk, Conn.With the rapid development of electronic technology, application field of electronic system is more and more extensive, electronic equipment, there are more and more people work with electronic equipment, life is increasingly close relationship. Any electronic equipment are inseparable from reliable power supply for power requirements, they more and more is also high. Electronic equipment miniaturized and low cost in the power of light and thin, small and efficient for development direction. The traditional transistors series adjustment manostat is continuous control linear manostat. This traditional manostat technology more mature, and there has been a large number of integrated linear manostat module, has the stable performance is good, output ripple voltage small, reliable operation, etc. But usually need are bulky and heavy industrial frequency transformer and bulk and weight are big filter.In the 1950s, NASA to miniaturization, light weight as the goal, for a rocket carrying the switch power development. In almost half a century of development process, switch power because of its small volume, light weight, high efficiency, wide range, voltage advantages in electric, control, computer, and many other areas of electronic equipment has been widely used. In the 1980s, a computer is made up of all of switch power supply, the first complete computer power generation. Throughout the 1990s, switching power supply in electronics, electrical equipment, home appliances areas to be widely, switch power technology into the rapid development. In addition, large scale integrated circuit technology, and the rapid development of switch power supply with a qualitative leap, raised high frequency power products of, miniaturization, modular tide.Power switch tube, PWM controller and high-frequency transformer is an indispensable part of the switch power supply. The traditional switch power supply is normally made by using high frequency power switch tube division and the pins, such as using PWM integrated controller UC3842 + MOSFET is domestic small power switch power supply, the design method of a more popularity.Since the 1970s, emerged in many function complete integrated control circuit, switch power supply circuit increasingly simplified, working frequency enhances unceasingly, improving efficiency, and for power miniaturization provides the broad prospect. Three end off-line pulse width modulation monolithic integrated circuit TOP (Three switch Line) will Terminal Off with power switch MOSFET PWM controller one package together, has become the mainstream of switch power IC development. Adopt TOP switch IC design switch power, can make the circuit simplified, volume further narrowing, cost also is decreased obviouslyMonolithic switching power supply has the monolithic integrated, the minimalist peripheral circuit, best performance index, no work frequency transformer can constitute a significant advantage switching power supply, etc. American PI (with) company in Power in the mid 1990s first launched the new high frequency switching Power supply chip, known as the "top switch Power", with low cost, simple circuit, higher efficiency. The first generation of products launched in 1994 represented TOP100/200 series, the second generation product is the TOPSwitch - debuted in 1997 Ⅱ. The above products once appeared showed strong vitality and he greatly simplifies thedesign of 150W following switching power supply and the development of new products for the new job, also, high efficiency and low cost switch power supply promotion and popularization created good condition, which can be widely used in instrumentation, notebook computers, mobile phones, TV, VCD and DVD, perturbation VCR, mobile phone battery chargers, power amplifier and other fields, and form various miniaturization, density, on price can compete with the linear manostat AC/DC power transformation module.Switching power supply to integrated direction of future development will be the main trend, power density will more and more big, to process requirements will increasingly high. In semiconductor devices and magnetic materials, no new breakthrough technology progress before major might find it hard to achieve, technology innovation will focus on how to improve the efficiency and focus on reducing weight. Therefore, craft level will be in the position of power supply manufacturing higher in. In addition, the application of digital control IC is the future direction of the development of a switch power. This trust in DSP for speed and anti-interference technology unceasing enhancement. As for advanced control method, now the individual feels haven't seen practicability of the method appears particularly strong,perhaps with the popularity of digital control, and there are some new control theory into switching power supply.（1）The technology: with high frequency switching frequencies increase, switch converter volume also decrease, power density has also been boosted, dynamic response improved. Small power DC - DC converter switch frequency will rise to MHz. But as the switch frequency unceasing enhancement, switch components and passive components loss increases, high-frequency parasitic parameters and high-frequency EMI and so on the new issues will also be caused.（2）Soft switching technologies: in order to improve the efficiency ofnon-linearity of various soft switch, commutation technical application and hygiene, representative of soft switch technology is passive and active soft switch technology, mainly including zero voltage switch/zero current switch (ZVS/ZCS) resonance, quasi resonant, zero voltage/zero current pulse width modulation technology (ZVS/ZCS - PWM) and zero voltage transition/zero current transition pulse width modulation (PWM) ZVT/ZCT - technical, etc. By means of soft switch technology can effectively reduce switch loss and switch stress, help converter transformation efficiency （3）Power factor correction technology (IC simplifies PFC). At present mainly divided into IC simplifies PFC technology passive and active IC simplifies PFC technology using IC simplifies PFC technology two kinds big, IC simplifies PFC technology can improve AC - DC change device input power factor, reduce the harmonic pollution of power grid.（4）Modular technology. Modular technology can meet the needs of the distributed power system, enhance the system reliability.（5）Low output voltage technology. With the continuous development of semiconductor manufacturing technology, microprocessor and portable electronic devices work more and more low, this requires future DC - DC converter can provide low output voltage to adapt microprocessor and power supply requirement of portable electronic devicesPeople in switching power supply technical fields are edge developing related power electronics device, the side of frequency conversion technology, development of switch between mutual promotion push switch power supply with more than two year growth toward light, digital small, thin, low noise and high reliability, anti-interference direction. Switching powersupply can be divided into the AC/DC and DC/DC two kinds big, also have AC/AC DC/AC as inverter DC/DC converter is now realize modular, and design technology and production process at home and abroad, are mature and standardization, and has approved by users, but the AC/DC modular, because of its own characteristics in the process of making modular, meet more complex technology and craft manufacture problems. The following two types of switch power supply respectively on the structure and properties of this.Switching power supply is the development direction of high frequency, high reliability, low consumption, low noise, anti-jamming and modular. Because light switch power, small, thin key techniques are changed, so high overseas each big switch power supply manufacturer are devoted to the development of new high intelligent synchronous rectifier, especially the improvement of secondary devices of the device, and power loss of Zn ferrite (Mn) material? By increasing scientific and technological innovation, to enhance in high frequency and larger magnetic flux density (Bs) can get high magnetic under the miniaturization of, and capacitor is a key technology. SMT technology application makes switching power supply has made considerable progress, both sides in the circuitboard to ensure that decorate components of switch power supply light, small, thin. The high frequency switching power supply of the traditional PWM must innovate switch technology, to realize the ZCS ZVS, soft switch technology has becomethe mainstream of switch power supply technical, and greatly improve the efficiency of switch power. For high reliability index, America's switch power producers, reduce by lowering operating current measures such as junction temperature of the device, in order to reduce stress the reliability of products made greatly increased.Modularity is of the general development of switch power supply trend can be modular power component distributed power system, can be designed to N + 1 redundant system, and realize the capacity expansion parallel. According to switch power running large noise this one defect, if separate the pursuit of high frequency noise will increase its with the partial resonance, and transform circuit technology, high frequency can be realized in theory and can reduce the noise, but part of the practical application of resonant conversion technology still have a technical problem, so in this area still need to carry out a lot of work, in order to make the technology to practional utilization.Power electronic technology unceasing innovation, switch power supply industry has broad prospects for development. To speed up the development of switch power industry in China, we must walk speed of technological innovation road, combination with Chinese characteristics in the joint development path, for I the high-speed development of national economy to make the contribution. The basic principle and component functionAccording to the control principle of switch power to classification, we have the following 3 kinds of work mode:1) pulse width adjustment type, abbreviation Modulation PulseWidth pulse width Modulation (PWM) type, abbreviation for. Its main characteristic is fixed switching frequency, pulse width to adjust by changing voltage 390v, realize the purpose. Its core is the pulse width modulator. Switch cycle for designing filter circuit fixed provided convenience. However, its shortcomings is influenced by the power switch conduction time limit minimum of output voltage cannot be wide range regulation; In addition, the output will take dummy loads commonly (also called pre load), in order to prevent the drag elevated when output voltage. At present, most of the integrated switch power adopt PWM way.2) pulse frequency Modulation mode pulse frequency Modulation (, referred to PulseFrequency Modulation, abbreviation for PFM) type. Its characteristic is will pulse width fixed by changing switch frequency to adjust voltage 390v, realize the purpose. Its core is the pulse frequency modulator. Circuit design to use fixed pulse-width generator to replace the pulse width omdulatros and use sawtooth wave generator voltage? Frequency converter (for example VCO changes frequency VCO). It on voltage stability principle is: when the output voltage Uo rises, the output signal controller pulse width unchanged and cycle longer, make Uo 390v decreases, and reduction. PFM type of switch power supply output voltage range is very wide, output terminal don't meet dummy loads. PWM way and way of PFM respectively modulating waveform is shown in figure 1 (a), (b) shows, tp says pulse width (namely power switch tube conduction time tON), T represent cycle. It can be easy to see the difference between the two. But they have something in common: (1) all use time ratio control (TRC) on voltage stability principle, whether change tp, finally adjustment or T is。
Energy conservation is a critical issue that affects the sustainability of our planet and the quality of life for future generations.Here are some key points to consider when writing an essay on protecting energy:1.Introduction to Energy ConservationBegin by introducing the concept of energy conservation and its importance. Mention the finite nature of energy resources and the need to use them wisely.2.Current Energy ConsumptionDiscuss the current patterns of energy consumption globally.Highlight the sectors that consume the most energy,such as transportation,industry, and residential use.3.Environmental ImpactExplain how excessive energy consumption contributes to environmental issues like climate change,air pollution,and resource depletion.Discuss the consequences of these issues for ecosystems and human health.4.Technological AdvancementsDescribe the role of technology in energy conservation,such as renewable energy sources solar,wind,hydro and energyefficient appliances.Mention smart grids and the integration of IoT for better energy management.5.Policies and RegulationsDiscuss government policies and international agreements aimed at promoting energy conservation,such as the Kyoto Protocol and the Paris Agreement.Highlight the role of carbon pricing and subsidies for renewable energy.6.Individual ActionsEmphasize the role of individuals in conserving energy through simple actions like turning off lights,using public transportation,and reducing water usage.Discuss the concept of a lowcarbon lifestyle and its benefits.cation and AwarenessStress the importance of education in raising awareness about the need for energy conservation.Discuss the role of schools,media,and community programs in educating the public.8.Economic BenefitsExplain how energy conservation can lead to economic benefits,such as reducedenergy bills and the creation of jobs in the renewable energy sector.Discuss the potential for energy efficiency to boost economic competitiveness.9.Challenges and BarriersAddress the challenges faced in promoting energy conservation,such as the initial costs of investing in renewable technologies and the resistance to change.Discuss the need for overcoming these barriers through innovation,policy support,and public engagement.10.ConclusionSummarize the main points of the essay.Reiterate the urgency of energy conservation and the collective responsibility of all stakeholders.End with a call to action,encouraging readers to contribute to the effort of protecting energy resources.Remember to use a variety of sources to support your arguments and to cite them appropriately.Writing in a clear,concise,and persuasive manner will help to effectively communicate the importance of energy conservation.。
Question 1:What is the acceleration of a freely falling object near the surface of the Earth, where the acceleration due to gravity is approximately 9.8 m/s²?A) 2.5 m/s²B) 4.9 m/s²C) 9.8 m/s²D) 19.6 m/s²Answer: C) 9.8 m/s²Question 2:A 2.0 kg mass is attached to a spring with a spring constant of 20 N/m. What is the maximum speed of the mass when it is oscillating with an amplitude of 0.10 m?A) 0.50 m/sB) 1.0 m/sC) 2.0 m/sD) 4.0 m/sAnswer: B) 1.0 m/sQuestion 3:An object is thrown vertically upwards with an initial velocity of 20 m/s. How long will it take for the object to reach its maximum height?A) 1.0 sB) 2.0 sC) 4.0 sD) 5.0 sAnswer: B) 2.0 sQuestion 4:A 10 Ω resistor and a 5 Ω resistor are connected in parallel. What is the equivalent resistance of the circuit?A) 2 ΩB) 5 ΩC) 10 ΩD) 15 ΩAnswer: A) 2 ΩQuestion 5:A 100 g ball is moving at a speed of 5 m/s and collides with astationary 200 g ball. If the collision is elastic, what is the speed of the first ball after the collision?A) 2.5 m/sB) 3.5 m/sC) 4.0 m/sD) 5.0 m/sAnswer: C) 4.0 m/sPhysics Section B: Short AnswerQuestion 6:Describe the process of photosynthesis and its importance to the Earth's ecosystem.Answer:Photosynthesis is a complex biochemical process by which green plants, algae, and some bacteria convert light energy, usually from the sun,into chemical energy stored in glucose. The process occurs in the chloroplasts of plant cells and involves several steps:1. Light-dependent reactions: These reactions take place in thethylakoid membranes of the chloroplasts. Water molecules are split, releasing oxygen as a byproduct, and electrons are transferred through the electron transport chain, creating a proton gradient across the thylakoid membrane.2. Calvin Cycle (Light-independent reactions): This cycle occurs in the stroma of the chloroplasts. Carbon dioxide is fixed into a stable intermediate, and ATP and NADPH produced in the light-dependent reactions are used to convert the intermediate into glucose.Photosynthesis is crucial for the Earth's ecosystem as it provides oxygen for aerobic organisms and serves as the foundation of the food chain. It also helps regulate the Earth's atmosphere by absorbing carbon dioxide, which helps mitigate climate change.Question 7:Explain the concept of electric potential and how it relates to electric fields.Answer:Electric potential, also known as voltage, is a measure of the electric potential energy per unit charge at a specific point in an electric field. It represents the amount of work done in bringing a unit positive charge from infinity to that point.The relationship between electric potential (V) and electric fields (E) is given by the equation:\[ V = -\int E \cdot dl \]This equation indicates that the electric potential difference (voltage) between two points in an electric field is equal to the negative line integral of the electric field strength along the path between the two points.In simpler terms, electric potential is a scalar quantity that describes the "height" or "energy level" of a point in an electric field. A higher electric potential means that more work is required to move a positive charge from that point to infinity. The electric field, on the other hand, is a vector quantity that indicates the direction and strength of the force experienced by a positive test charge placed at a given point in the field.。
2019IMP&HIRFL Annual Report·311·References[1] C.T.Liu,S.M.Bai,X.Y.Ren,et al.,Radiation Protection,16(2)(1996)121.(in Chinese)[2] C.T.Liu,Radiation Protection,12(2)(1996)122.(in Chinese)7-56Shielding Design of HIAFLi Yang,Li Wuyuan,Mao Wang,Wang Lijun,Yan Weiwei and Yang Bo High Intensity heavy-ion Accelerator Facility(HIAF)is designed by the Institute of Modern Physics,Chinese Academy of Sciences,which can accelerate particles form proton up to uranium.As shown in Fig.1,HIAF is composed of the following parts:Superconducting Electron Cyclotron Resonance(SECR)ion source,Linear Accelerator(LINAC),Low Energy experimental terminal(LET),high intensity synchrotron BRing(Booster Ring), High Energy experimental terminal(HET),super-conducting radioactive bema line HFRS(HIAF FRagment Separator),multi-function high precision synchrotron SRing(Spectrometer Ring)and High Energy Density(HED) experimental terminal.In the process of beam acceleration and transport,some accelerated particles will be lost in the surrounding materials(such as the beam pipe)and produce secondary particles dominated by high-energy neutrons with strong penetrability.These secondary particles make up prompt radiation.To protect the facility personnel and the general public from radiation exposure,shielding design should be conducted.Shielding calculation of LINAC,BRing,SRing,HET and HED based on analytical methods and Monte Carlo simulation has been made.According to the reports of International Commission on Radiological Protection[1]and National Council on Radiation Protection and Measurement[2],the occupational and annual public dose limit are20and1mSv, respectively.The same values are also provided in Chinese Standard GB18871-2002[3].The standard(GBZ/T201-2007)requires that dose rate at30cm outside the shielding wall should be less than2.5µSv/h[4].J-PARC shielding design report suggests that dose rate in soil at100cm outside the shielding wall should be less than 5.5mSv/h[5].For a conservative design,the dose limit used in shielding design of HIAF is listed in Table1.The occupational exposure is5mSv(one-fourth of the standard),and exposure to the public is0.1mSv(one-tenth of the standard).Table1Dose limit used in HIAF shielding design.Dose limit type Standard Objective Occupational dose limit/(mSv/year)205 Public dose limit/(mSv/year)10.1Dose rate limit/(µSv/h) 2.5 2.5 For the sake of shielding cost,HIAF is built underground.The shielding structure includes tunnel primary shielding and local shielding.The tunnel primary shielding is determined by the beam uniform loss in beam pipe. While the local shielding is determined by the beam intensive loss in some point such as beam dump.In the design of tunnel primary shielding,we constructed a rectangle-tunnel geometric model(see Fig.2)using Monte Carlo code FLUKA[6]to represent the real rectangle-tunnel,whose length is50m.The inner radius and outer radius of the beam pipe are5and6cm,respectively.Secondary radiationfield depends on the projectile type,incident energy. Tofind the maximum radiationfiled,we preliminarily simulate serval typical particle acceleration and eventually determined the beam loss parameters(see Table2)subsequently used in calculation of shielding thickness.In the design of local shielding,we focused on the beam dump in high-energy experimental terminal(HET),air duct and versatile shaft.The local shielding for air duct and versatile shaft is very complicated.It refers to specific structure. Given space limitations,we only introduce the technique used in local shielding calculation.The structure like duct/shaft with large empty space and thick shielding will pose a big challenge for the computational efficiency when a straight forward Monte Carlo simulation is used.To solve this problem,we adopt the so-called two-step method, that is,we split one run into multiple runs by editingfluscw.f and source.f.With this approach,the computational efficiency was significantly improved.Finally,we calculated the shielding thickness required to meet dose limit.The results are listed in the Table3. Note that partial results are presented.·312·IMP&HIRFL Annual Report2019Table2Beam loss parameters used in tunnel primary shielding calculation.Tunnel Ion Energy/(MeV/u)Intensity/ppsLINAC p48 1.3E+11BRing12C1380 2.3E+7SRing12C1500 3.3E+7Table3The calculated shielding thickness of HIAF.Lateral wall/m Cell wall/m Bottom wall/m Frontal wall/m Number AreaConcrete Concrete+soil Concrete Concrete 1LINAC0.6 1.20.6\2BRing0.8 1.2+4.30.8\3SRing0.9 1.2+4.60.9\4HET 1.9 1.2+6.5 2.57Fig.1(color online)The layout of HIAF.Fig.2(color online)The calculation mode for the tunnelconstructed by FLUKA.References[1] A.D.Wrixon,NeW ICRP Recommendations.J.Radiol.Prot.,28(2008)161.[2]NCRP Report NO.144,Radiation Protection for Particle Accelerator Facilities,113(2005)456.[3]National Standard,GB18871-2002,Basic Standards Fort Protection against Ionizing Radiation and for the Safety of RadiationSources.[4]National Standard,GBZ/T201-2007,Radiation Shielding Requirements in Room of Radiotherapy Installations.[5]T.Mura,N.Gun,I.Ken.JEARI-Tech-2004-001-part,2(2004)878.[6]http://www.fl.7-57Disposal of Hazardous Waste Produced by the Laboratories and Purchase of Precursor Chemicals in2019Wang Lijun,Su Youwu,Li Wuyuan,Yang Bo and Mao WangHazardous waste such as waste liquid,experimental waste,expired reagents and others that are produced by biological laboratory and chemical laboratory in the process of materials,biophysics and medical physics researching. According to the national law and standard[1],those waste must be carefully managed and controlled for environment and public safety.The collection,classification and sorting of waste chemical reagents[2]and solutions produced by all the laboratories of the institute had been completed in2019[3].A total of27.7kg waste chemical reagents,2765kg waste liquid。
Chapter 1 Introduction（引言）§1.1 Space and Time（空间与时间）universe宇宙object物体measurement 测量kinematics运动学motion of objects 物体的运动mass point/particle质点center of mass 质心space and time 时空rotation 旋转subject研究的对象phenomena 现象intergalactic星系间的submicroscopic 亚微观的dimension尺度uniform均匀的isotropic各向同性的continuous连续的direction方向graininess 颗粒性location位置frame of reference 参考系specify确定、规定simultaneously 同时地inconsistent with与…不一致define/definition 定义platinum-iridium铂铱合金atomic standard 原子标准transition 跃迁meridian子午线general conference on weights and measures 国际计量大会vacuum真空former standard of length米原器atomic energy level原子能级isotope cesium 铯同位素krypton 氪angstrom埃§1.2 Coordinate Systems and Frames of Reference（坐标系与参考系）frame of reference 参考系coordinate system坐标系rectangular Cartesian coordinates直角笛卡儿坐标系axis / axes (pl.)（坐标）轴origin坐标原点at rest静止dimension维mutually perpendicular 互相垂直intersection 交点§1.3 Idealized Models（理想模型）idealized model 理想模型simplified version简化方式neglect忽略particle质点air resistance 空气阻力vacuum真空in terms of 利用rigid body刚体insulator绝缘体§1.4 Vectors（矢量）vector矢量scalar标量magnitude大小velocity速度acceleration 加速度momentum动量proportional to正比于parallel平行position vector位置矢量§1.5 Properties of Vectors（矢量的特点）resultant/net vectoradditionsubtractionequivalenttranslatehead-to-tail methodparallelogram method diagonalcommutative lawscalar productdot productdistributive lawmultiplicationcross product vector productarearight-hand ruleparallelmultiplyfunctionsome variable§1.6 Components of a Vector（矢量的分量）component分量absolute value绝对值projection投影perpendicular 垂线rectangular component正交分量§1.7 Unit Vectors（单位矢量）unit vector单位矢量dimensionless 无量纲的unit magnitude单位大小respectively分别地Chapter 2 Kinematics: Motion in Two and Three Dimensions （运动学：二维与三维运动）§2.1 Kinematical Function of a Point（质点的运动函数）position vector位置矢量trigonometry 三角学§2.2 Displacement and Velocity（位移与速度）trajectory轨迹displacement vector位移矢量velocity速度ratio比值，比率straight line直线approach趋近、接近limit极限average velocity 平均速度instantaneous velocity瞬时速度slope斜率chord弦limiting process 求极限过程curved path弯曲路径derivative导数magnitude and direction大小和方向speed速率scalar components标量分量limiting value极限值limiting process 求极限过程tangent相切、切线change增量、改变量differential n.微分differentiate v. 微分、求导integrate v.积分integration n.积分coefficient系数module (矢量的)模successively 连续地square root 平方根§2.3 Acceleration（加速度）acceleration 加速度average acceleration 平均加速度instantaneous acceleration 瞬时加速度second derivative二阶导数positive正的negative负的respectively 分别地one-dimensional motion一维运动uniform circular motion匀速圆周运动projectile motion抛体运动§2.4 Motion with Constant Acceleration（匀加速运动）无§2.5 Linear Motion with Constant Acceleration（匀加速直线运动）linear线性的one-dimensional一维的corresponding对应的eliminate消去freely falling bodies自由落体air resistance 空气阻力acceleration due to gravity 重力加速度altitude高度vertical direction 竖直方向negative sign 负号latitude经度regardless of与.无关maximum value最大值minimum value最小值§2.6 Projectile Motion （抛体运动）projectile抛体trajectory轨迹assumption 假设negligible可忽略的rotation 转动air friction 空气摩擦parabola抛物线parabolic trajectory 抛物线轨迹initial初始的horizontal水平的independent 独立的superposition叠加flight time飞行时间horizontal range射程maximum height最大高度horizontal surface水平面a body projected horizontally平抛物体vertical竖直的firing angle抛射角§2.7 Circular Motion（圆周运动）circular motion 圆周运动uniform circular motion匀速圆周运动circular motion with varying speed变速圆周运动centripetal向心的arc length 弧长angular displacement 角位移instantaneous angular velocity（瞬时）角速度radian(s) 弧度dimensional有量纲的counterclockwise 逆时针clockwise顺时针circle圆center of a circle圆心vectorially矢量地angular acceleration 角加速度tangential acceleration 切向加速度center-seeking 向心resolve （矢量）分解centripetal acceleration 向心加速度normal acceleration 法向加速度perpendicular to垂直于radial径向的radius半径§2.8 Relative Motion（相对运动）relative velocity相对速度relative acceleration 相对加速度observer观察者outcome结果measurement 测量stationary 静止的differentiate求微分Galilean transformation equation伽利略变换valid有效的special theory of relativity狭义相对论as it turns out结果是relative to相对于heading due north头朝北right triangle直角三角形upstream逆流hypotenuse直角三角形的斜边Chapter 3 Newton’s Laws of Motion（牛顿运动定律）§3.1 Newton’s First Law（牛顿第一定律）at rest静止net external force/ resultant force合外力inertial frame of reference 惯性参考系inertia惯性act on = exert（力）作用于approximation近似inertial mass 惯性质量interact (n. interaction)相互作用resultant external force合外力momentum动量unless stated otherwise 除非另有说明§3.2 Newton’s Second Law（牛顿第二定律）nonzero非零的mass质量momentum动量rate of change变化率directly proportional to正比于inversely proportional to反比于§3.3 Newton’s Third Law（牛顿第三定律）interact相互作用opposite相反、相对isolated 孤立的action force 作用力reaction force反作用力§3.4 Applications of Newton’s Laws（牛顿运动定律的应用）tension 张力diagram示意图isolate 隔离free-body diagram受力图unknown未知量Atwood’s Machine阿特伍德机light string轻绳vertically 竖直地frictionless 无摩擦的incline斜面pulley滑轮balanced平衡的block 木块、滑块wedge楔、斜铁plane 平面horizontal surface水平面§3.5 International Units and Dimensions（国际单位制与量纲）physical quantity物理量fundamental unit基本单位universally普遍scientific community科学界luminous intensity光强度abbreviation缩写lowercase小写的uppercase大写的rectangle矩形§3.6 Introduction to Some Common Forces（几种常见力）electromagnetic电磁的lean against 倚靠compress 压mattress spring 床垫弹簧normal force 法向力、支持力stiffness倔强性stretch 拉伸frictional force / force of friction 摩擦力viscous medium粘滞媒质（介质）resistance 阻力force of static friction 静摩擦力maximum force of static friction最大静摩擦力is proportional to正比于proportionality constant比例常数coefficient of static friction 静摩擦系数coefficient of kinetic friction 滑动摩擦系数variation变化§3.7 The Four Fundamental Forces（四种基本力）gravitational force 引力universal gravitational constant万有引力常数electromagnetic force电磁力bind约束Coulomb’s law库仑定律charged particle带电粒子strong nuclear force 强力hydrogen氢nucleus (pl. nuclei or nucleuses)原子核neutron 中子proton质子counteract抵抗repulsive排斥的strength强度weak nuclear force弱力short-range force 短程力radioactivity放射性radioactive decay 放射性衰变nucleons核子massless 无质量的action at a distance远程作用hypothesis 假设field场Chapter 4Linear Momentum and Angular Momentum （动量与角动量）§4.1 Linear Momentum and Impulse（动量与冲量）(linear) momentum动量impulse 冲量impulse-momentum theorem动量定理time-average force 平均冲力§4.2 Impulse-momentum Theorem for Particles System（质点系的动量定理）particles system 质点系internal forces 内力external forces 外力§4.3 Conservation of Linear Momentum（动量守恒定律）momenta（pl.）动量§4.4 Center of Mass（质心）vector notation矢量表示continuous object连续物体element of mass 质元§4.5 Motion of the Center of Mass（质心的运动）conserved 守恒的isolated system 孤立系统§4.6 Angular Momentum of a Particle（质点的角动量）conserved 守恒的isolated system 孤立系统§4.7 Conservation Law of Angular Momentum（角动量守恒定律）Kepler 开普勒ellipse椭圆Chapter 6 Rotation of a Rigid Body about a Fixed Axis （刚体的定轴转动）§6.1 Motion of a Rigid Body（刚体的运动）rigid body刚体parallelogram rule 平行四边形法则translation 平动an extended body 空间实体rotation 转动nondeformable 不变形的resultant motion 合运动parallel平行fixed axis 固定轴counterclockwise motion 逆时针运动angular acceleration 角加速度clockwise motion顺时针运动separation 间隔translation 平动angular velocity 角速度trajectory 轨迹§6.2 Law of Rotation of a Rigid Body about a Fixed Axis（刚体定轴转动定律）moment of inertia 转动惯量rotation axis 旋转轴torque 力矩proportionality constant比例常数element of mass 质元line of action of force 力的作用线analogue 类似；相似perpendicular distance垂直距离distribution of mass 质量分布pivot about 围绕…旋转；以…为轴旋转moment arm 力臂is proportional to与…成正比§6.3 Calculation of Moments of Inertia for Rigid Bodies（转动惯量的计算）an extended body 延续实体hoop圆环spherical shell薄球壳solid sphere实心球spherical cavity球腔linear density线密度§6.4 Application of Law of Rotation of a Rigid Body about a Fixed Axis（刚体定轴转动定律应用）orientation 方向；方位atwood’s machine伍德机brake制动器，刹车pedal踏板sprocket链轮齿bearing轴承pulley滑轮nonslip 无滑动§6.5 Conservation of Angular Momentum with Respect to the Fixed Axis（对定轴角动量守恒）resultant external torque合外力矩isolated隔离的valid 有效；适用pin 销；轴hapter 7Electric Fields of Stationary Electric Charges（静止电荷的电场）§7.1 Charge（电荷）Electricity电学magnetism磁学accelerator 加速器interatomic原子间的amber琥珀magnetite磁铁矿electrification充电magnet磁铁charge 电荷quantized量子化的quantization量子化proton质子electrically charged带电的charged body带电体conservation守恒uncharged不带电的§7.2 Coulomb’s Law（库仑定律）Coulomb’s Law库仑定律inversely proportional to相反地separating 分开的permittivity介电常数hydrogen氢opposite sign符号相反§7.3 The Electric Field（电场）electric field 电场test charge检验电荷distribution分布X-ray X-射线lightning闪电electronic电子的intermolecular分子间的rub摩擦magnesia氧化镁electromagnetism电磁学plastic rod塑料棒repel排斥attract 吸引suspend悬挂neutron中子electron电子neutral中性的integer整数integral multiple整数倍proportional to正比于square平方product乘积repulsive排斥Coulomb constant库仑常数superposition principle叠加原理electric field (intensity) 电场强度source charge场源电荷radio waves无线电波atmosphere大气thundercloud 雷雨云§7.4 Calculation of Electric Field（电场的计算）stationarydenominatorelectric dipoleelectric dipole moment spherically symmetriccontinuous charge distributioncharge elementstrategy静止的分母电偶极子电偶极矩球对称电荷连续分布元电荷策略bisector平分线manipulation处理linear charge density电荷线密度surface charge density 电荷面密度volume charge density电荷体密度ring charge带电圆环charged disk带电圆盘infinite plate of charge无限大带电平面§7.5 Electric Field Lines and Electric Flux（电场线和电通量）electric field lines电场线electric flux电通量infinity无穷远visualize形象化strength强度penetrate穿过qualitative定量的closed surface闭合曲面align排列thread线intersection 相交cross交叉§7.6 Gauss’s Law（高斯定理）Gauss’s law 高斯定理arbitrary shape 任意形状gaussian surface 高斯面electric flux电通量principle 原理practice实际§7.7 Application of Gauss’s Law（高斯定理的应用）algebraic代数的rearrange重新整理charge distribution电荷分布spherical symmetry 球对称cylindrical symmetry 柱对称plane symmetry 平面对称symmetric对称的spherical shell球壳infinite length无限长infinite plane无限大平面Chapter 8 Electric Potential（电势）§8.1 Conservativity of Electrostatic Field（静电场的保守性）line integral线积分conservative force field 保守力场closed path闭合路径conservative保守的circuital theorem for electrostatic field静电场环路定理§8.2 Potential Difference and Electric Potential（电势差和电势）potential difference电势差electric potential电势infinity无穷远electrostatic potential energy 静电势能volt伏特voltage电压electron volt电子伏特battery电池§8.3 Calculation of Electric Potential（电势的计算）equipotential surface等势面broken lines虚线semicircular半圆的insulating绝缘的infinite无限的dashed lines虚线extend延伸solid lines实线finite有限的arbitrary任意的function函数curved surface曲面§8.4 Electric Potential Gradient（电势梯度）gradient梯度notation符号potential Gradient电势梯度maximum最大值right angle 直角sketch勾画§8.5 Electrostatic Potential Energy（静电势能）electrostatic potential energy 静电势能vicinity附近Chapter 9 Conductor in Electrostatic Field（静电场中的导体）§9.1 Conductors in Electrostatic Equilibrium（导体的静电平衡）isolated conductor 孤立导体electrostatic equilibrium静电平衡equipotential body等势体radius of curvature曲率半径electrostatic shielding静电屏蔽neutralize电中和sharp point discharge尖端放电lightning rod 避雷针cosmic rays 宇宙射线lightning stroke雷击glow discharge 辉光放电ion离子corona discharge电晕放电shrink收缩cavity 空腔grounding接地curved surface 曲面conducting wire导线collision碰撞thunderstorm雷暴induced charge 感应电荷insert插入guarantee保证contradiction 矛盾§9.2 Calculation of Electrostatic Field with Conductors Nearby （有导体存在时静电场的分析与计算）conducting slab 导电板lateral area侧面uncharged conductor不带电导体edge effect边缘效应redistribute 重新分配external外部Chapter 10 Capacitors and Dielectrics in Electrostatic Field （电容器和静电场中的电介质）§10.1 Capacitance and Capacitors（电容和电容器）Leyden jar 莱顿瓶flash 闪光灯capacitance电容coaxial同轴的capacitor电容器coaxial cable同轴电缆parallel-plate capacitor 平行平板电容器concentric同心的cylindrical capacitor圆柱形电容器parallel combination 并联spherical capacitor 球形电容器series combination串联submultiple因数farad 法拉microfarad 微法拉picofarad 皮法拉rectify 调整inductance 自感应ignition 点火sparking打火花metallic金属(性)的combination联合、组合equivalent相当的§10.2 Dielectrics and Electric Field（电介质与电场）dielectric电介质relative dielectric constant 相对介电常数voltmeter 伏特计insulating绝缘的dielectric breakdown介质击穿dielectric strength介电强度§10.3 Polarization of Dielectrics（电介质的极化）polarize极化polar molecules极性分子polarization 极化nonpolar molecules非极性分子induced dipole moments 感应电矩permanent electric dipole moments 固有电矩surface charge表面电荷align排成一线orient取向bound charge束缚电荷homogeneous 均匀的free charge 自由电荷microwave 微波oven 烤箱vibrate 振动tune 调整resonate 共振oscillate 振荡§10.4 Gauss’s Law for Electric Displacement Vector （高斯定律）electric displacement 电位移dielectric constant介电常数deliberately故意地the flux of D(r) D(r) 的通量permittivity电容率§10.5 Energy Stored in a Charged Capacitor（电容器的能量）transfer转移electrostatic potential energy 静电势能battery电池electrostatic field energy 静电场能increment 增量energy density能量密度transformation转化maximum operating voltage 最大工作电压terminal 终端deliver递送dissipate消散pathway路径Chapter 11 Magnetic Force (磁力)§11.1 Nature of Magnetic Force(磁力的本质)magnetite磁铁矿石bar magnet条形磁铁interaction 相互作用magnetic pole磁极electric current loops of molecules分子环形电流§11.2 Magnetic Field and Magnetic Field Vector(磁场和磁感应强度)magnetic field磁场magnetic field vector=magnetic induction =magnetic flux density磁感应强度magnetic force 磁场力Lorentz force 洛仑兹力B-line磁感(应)线magnetic flux磁通量tesla(T)特（斯拉）weber韦伯§11.3 Motion of a Charged Particle in a Magnetic Field(带电粒子在磁场中的运动)cyclotron period回旋周期magnetic focusing磁聚焦helix螺旋线pitch螺距magnetic lens磁镜magnetic confinement 磁约束a magnetic bottle磁瓶the mass spectrometer 质谱仪schematic drawing示意图ion离子precision 精确度proton质子deuteron 氘核bombard 轰击cyclotron 加速器dees D型盒evacuate抽成真空shield屏蔽oscillate 振动plasma等离子体nuclear fusion核聚变Van Allen belts范阿仑辐射带§11.4 The Hall Effect(霍尔效应)the Hall voltage 霍尔电压the drift velocity漂移速度§11.5 Magnetic Force on a Current-carrying Conductor(载流导体在磁场中受力—安培力)current-carrying conductor/wire载流导体/导线current loop in a uniform magnetic field匀强磁场中的载流线圈linear element 线元current element vector 电流元矢量loop 环, 回路magnetic moment of a current loop载流线圈磁矩rectangular loop矩形回路a wire segment 一段导线strip 条；带Chapter 12 Source of Magnetic Field（磁场的源）§12.1 The Magnetic Field of Moving Point Charges（运动点电荷的磁场）permeability of free space真空磁导率§12.2 The Biot-Savart Law（毕奥-萨伐尔定律）the Biot-Savart Law毕奥-萨伐尔定律permeability of free space真空磁导率Gauss’law in magnetism磁场的高斯定律magnetic monopoles磁单极solenoid螺线管turn匝current-carrying wire 载流导线encircle环绕current element电流元diverge发散converge聚合magnetic pole磁极magnet磁铁magnetic flux磁通量§12.3 Ampere Circuital Theorem （安培环路定理）penetrate穿过bounded by以…为边界finite point 有限点line integral线积分§12.4 Application of Ampere Circuital Theorem（安培环路定理的应用）current-carrying wire 载流导线circumference 周长cylindrical shell圆柱形壳toroid螺绕环inner radius 内径outer radius外径spherical conductor 球形导体§12.5 Magnetic Field due to Varying Electric Field（与变化的电场相联系的磁场）displacement current位移电流generalized Ampere’s Law广义安培环路定理conduction current传导电流magnetic monopole磁单级postulate假设total current全电流steady current恒定电流§12.6 The Magnetic Force Between Two Parallel Current-carryingWires（平行电流间的相互作用力）antiparallel反平行Chapter 13 Magnetic Media in Magnetic Field（磁场中的磁介质）§13.1 Effect on Magnetic Field Caused by Magnetic Media（磁介质对磁场的影响）magnetic medium磁介质diamagnetic medium抗磁质paramagnetic medium顺磁质ferromagnetic material 铁磁质magnetic moment 磁矩paramagnetism 顺磁性partial alignment部分取向electron spin 电子自旋magnetic dipole 磁偶极子ferromagnetism 铁磁性diamagnetism抗磁性induced magnetic moment感生磁矩permanent magnetic moment固有磁矩§13.2 Atomic Magnetic Dipole Moments（原子磁矩）magnetization磁化atomic原子的magnetic dipole moment磁矩orbital magnetic moment 轨道磁矩quantum theory量子理论intrinsic spin angular momentum内禀自旋角动量§13.3 Magnetization（磁介质的磁化）magnetization n.磁化、磁化强度magnetize . 磁化atomic current loopamperian currentcross-sectional area分子环流v安培电流横截面积induced magnetic dipole moments感生磁矩surface magnetization current/ bound current 面磁化电流(面束缚电流)applied magnetic field外加磁场magnetic susceptibility磁化率relative permeability相对磁导率bismuth 铋Bohr magneton玻尔磁子superconductor超导体emf电动势§13.4 Ferromagnetic Materials（铁磁质）iron铁cobalt钴nickel镍alloy 合金ferromagnetism 铁磁性magnetic domain磁畴critical temperature临界温度Curie temperature居里温度thermal agitation热扰动end effect边界效应magnetic saturation磁饱和reversible 可逆的magnetic hysteresis磁滞效应hysteresis loop 磁滞回线magnetization curve磁化曲线initial magnetization curve起始磁化曲线remnant magnetization剩磁coercive force矫顽力memory 记忆能力magnetize磁化demagnetize去磁，退磁transformer 变压器motor 电动机secondary coil副线圈cycle循环irreversible process 不可逆过程hard ferromagnetic materials硬磁性材料soft ferromagnetic materials软磁性材料hysteresis loss磁滞损耗（铁损）Curie point居里点permanent magnet永久磁体, magnetic tape磁带，memory unit记忆元件iron cores铁芯galvanometer 电流计rr§13.5 Circuital Theorem for H （H 的环路定理）magnetic intensity磁场强度magnetization current 磁化电流free current自由电流isotropic各向同性的permeability磁导率relative permeability相对磁导率Chapter 14 Electromagnetic Induction（电磁感应）§14.1 Faraday Law of Electromagnetic Induction（法拉第电磁感应定律）electromagnetic induction 电磁感应induction current感应电流emf (electromotive force) 电动势induction emf 感生电动势weber韦伯Lenz Law楞次定律polarity极性§14.2 Motional emf（动生电动势）motional emf 动生电动势§14.3 Induced emf and Induced Electric Field（感生电动势和感生电场）nonelectrostatic force非静电力induced emf 感生电动势induced electric field感生电场vortex field涡旋场eddy currents 涡流nonconservative field 非保守场time-varying field时变场alternate变化alternative 交流电的，交变的laminated叠片（组成）的§14.4 Mutual Induction（互感现象）mutual induction互感现象mutual inductance互感系数emf by mutual induction互感电动势orientation 方位§14.5 Self-induction（自感现象）self-induction自感现象self-inductance 自感系数inductor电感self-induced emf 自感电动势is proportional to正比于§14.6 Energy of Magnetic Field（磁场的能量）magnetic energy density磁场能量密度energy due to mutual induction互感磁能Chapter 15 Maxwell’s Equations and Electromagnetic Waves （麦克斯韦方程组组与电磁波波）§15-1 Maxwell’s Equations（麦克斯韦方程组）§15-2 Electromagnetic Waves（电磁波）propagation传播in phase同相、同步transverse waves横波wavelength波长visible spectrum可见光谱infrared waves 红外波radiation 辐射ultraviolet ray紫外线Poynging vector 坡印亭矢量§15-3 The Wave Equation for Electromagnetic Waves（电磁波的方程）wave function波函数wave equation波的方程wave number 波数angular frequency 角频率plane wave平面波Chapter 16 Temperature and the Kinetic Theory of Gases（温度与气体运动论）§16.1 Thermal Equilibrium and Temperature （热平衡及温度）temperature 温度hotness热coldness冷thermometric property热力学特性thermal contact热接触the average internal molecular kinetic energy 分子内平均动能thermal equilibrium热平衡electrical conductor 导电器the zeroth law of thermodynamics热力学第零定律temperature scale温标§16.2 The Celsius and Fahrenheit Temperature Scales（摄氏温标与华氏温标）thermometer温度计temperature scale温标the ice-point temperature冰点温度freezing point冰点steam-point沸点normal boiling point标准沸点the steam-point temperature 气化点温度the Celsius temperature scale摄氏温标the Fahrenheit temperature scale华氏温标§16.3 Gas Thermometers and the Absolute Temperature Scale（气体温度计和绝对温标）calibrate 校对、校准discrepancy差异volume 体积density密度sufficiently low 足够低sulfur硫a constant-volume gas thermometer等容气体温度计triple point of water 水的三相点ideal-gas temperature scale理想气体温标absolute temperature scale绝对温标nitrogen氮hydrogen氢oxygen氧recalibrate再校准extrapolate外推，向外延长triple point 三相点coexist共存helium氦liquefy液化in terms of 利用rigid body刚体insulator绝缘体Kelvin scale 开尔文温标§16.4 The Ideal-Gas Law（理想气体定律）Boyle’s law玻意耳定律constant volume 等体Boltzmann’s constant玻耳兹曼常量mole摩尔Avogadro’s number 阿伏伽德罗常量carbon atom碳原子universal gas constant普适气体常量ideal gas理想气体equation of state状态方程state variable状态参量standard condition标准条件subscript 下标§16.5 The Kinetic Theory of Gases（气体分子运动论）macroscopic state variable宏观状态变量microscopic quantity微观量walls of a container容器壁translational kinetic energy平动动能root mean square (rms) speed方均根速率order of magnitude量级piston活塞redistribute 再分布partition 分配equipartition theorem（能）均分定理classical statistical mechanics经典统计力学degree of freedom自由度monatomic 单原子的bond键diatomic 双原子的polyatomic 多原子的vibration振动mean free path平均自由程air current 气流convection 对流diffuse扩散reciprocal倒数frequency频率§16.6 Maxwell Speed Distribution Function（麦克斯韦速率分布函数）probability概率abscissa横坐标normalization condition 归一化条件most probable distribution最概然分布Chapter 17 Heat and the First Law of Thermodynamics （热及热力学第一定律）§17.1 Heat Capacity and Specific Heat（热容与比热）atomist 原子学家thermal energy 热能manifestation 表现形式molecular motion 分子运动thermal contact热接触caloric a.热的n.热（质）internal energy 内能heat capacity热容量phase相heat conduction热传导calorie卡（路里）molar mass摩尔质量Law of conservation of energy能量守恒定律The first law of thermodynamics 热力学第一定律be proportional to和…成正比molar specific heat摩尔比热solar heating system太阳能热系统coolant冷却液§17.2 Change of Phase and Latent Heat（相变与潜热）heat capacity热容量phase change相变vaporization汽化，蒸发fusion 熔化melting融化condensation 凝聚sublimation升华carbon dioxide二氧化碳crystalline a. 结晶的、晶状的n.结晶体average translational kinetic energy平均平动动能latent heat潜热§17.3 Joule’s Experiment（焦耳实验）thermally insulated绝热的mechanical equivalence of heat热功当量§17.4 The Internal Energy of an Ideal Gas（理想气体内能）internal energy 内能real gas实际气体§17.5 Work and the PV Diagram for a Gas（功与气体PV图）quasi-static process准静态过程piston活塞isobaric等压的isothermal 等温的§17.6 The First Law of Thermodynamics（热力学第一定律）§17.7 Heat Capacities of Gases（气体的热容）infinitesimal无穷小的§17.8 The Quasi-Static Adiabatic Process for an Ideal Gas（理想气体准静态绝热过程）compression 压缩Poisson formula 泊松公式process equations 过程方程。
