Power and Energy,a Real Challenge and Opportunity

The International Conference of Power and Energy,Chinaunder the sponsorship of Chinese Society of ElectricalEngineering,and co-sponsorship of the Chinese Societyof Power Engineering,China Energy Research Society,East WestCenter (USA) and McGraw-Hill Publishing Company (USA),wasduly held from Oct.22 to Oct.26,!990.Over 100 experts and schol-ars from USA,USSR,France,Austria,Japan,Germany,UK,Poland,Czechoslovakia,Finland,Hungary,Switzerland,Norway,Italy and     

Electromagnetic field diffusion, θ-functions,and image solutions

Contents We discuss some initial and boundary value problems of one-dimensional electromagnetic field diffusion. The solutions can be given by infinite series in two essentially different (however equivalent) forms, one being the usual Fourier-expansion and the other one being an infinite series of Gaussian exponentials or related functions (as for instance error-functions). The second form can be obtained by using infinitely many images to fulfill initial and boundary conditions. Finally the mathematical relations between the two equivalent types of solutions are discussed in terms of -functions and their transformation properties. The existence of the solutions in these two different forms is very interesting from a numerical point of view also.

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Die Diffusion elektromagnetischer Felder, -Funktionen und Spiegelungsmethoden

Übersicht Es werden einige Anfangs- und Randwertprobleme eindimensionaler elektromagnetischer Felddiffusion erörtert. Die Lösungen können in zwei wesentlich verschiedenen (jedoch gleichwertigen) Formen angegeben werden, erstens in Form üblicher Fourier-Reihen und zweitens in Form unendlicher Reihen von Gaußschen Exponentialfunktionen oder damit verwandter Funktionen (z.B. Fehlerfunktionen). Diese zweite Form der Lösungen läßt sich durch die Anwendung unendlich oft wiederholter Spiegelung zur Erfüllung der Rand- und Anfangsbedingung anschaulich interpretieren. Abschließend werden die beiden Lösungstypen mit Hilfe von -Funktionen und deren Transformationseigenschaften erläutert. Die Verfügbarkeit der Lösungen in beiden Formen ist auch numerisch sehr interessant.

     

Current status and challenges in PEMFC stacks, systems and commercialization

Polymer electrolyte membrane fuel cells(PEMFCs)operate atlowtemperatures(60~80℃),offer a fast start-up and shut downti me(few minutes),fast response to changing electric loads,andcan sustain unli mited thermal cycles·They are ideally suited fortransport…     

The Transformer Short-Circuit Test and the High Power Laboratory in China-the Past, Present, and Future

We review the short-circuit testing of distribution and power transformers, and include a list of 110-220kV power transformers tested up to February 2002.     

Past, Present and Future of PXI

Since its first introduction more than 25 years ago, the concept of Virtual Instrumentation has now been widely adopted in automated test and measurement industry. Virtual Instrumentation allows users to create a user-defined system by combining modular h…     

The Transformer Short-Circuit Test and the High Power Laboratory in China-the Past,Present,and Future

IntroductionOver the last half century, the transform erindustry in China has experienced substan-tial developm ent. Prior to 1949, only distributiontransform ers up to 2000 kV A /33 kV were pro-duced;however,by the end of last century,Chinawas producing …     

China Power Systems, Today and Tomorrow

Through rapid extension and incessant improvement of 500 kV (including 330 kV) and 220 kV transmission trunk networks, China power systems have entered a new era of large power networks, large power plants, large power units, extra-high voltage transmission and highly automatic control. It is symbolized by the installed generating     

GTI''''s hydrogen programs: hydrogen production, storage, and applications

1 Hydrogen production and storageBeginningin 2000,Gas Technology Institute(GTI)made amajor commitment to combine its core competency in compressedgas systems and fuel processing·This resultedin a major collabora-tive program with the U·S·Department of …     

Past, present and future of fuel cells

Ｉｎ 18 3 9,Ｇｒｏｖｅ[1] ｐｕｂｌｉｓｈｅｄｈｉｓｓｔｕｄｉｅｓｏｎｔｈｅｇｅｎｅｒａｔｉｏｎｏｆｅｌｅｃｔｒｉｃｉｔｙｂｙｃｏｎｎｅｃｔｉｎｇｔｗｏｐａｒｔｉａｌｌｙｉｍｍｅｒｓｅｄｐｌａｔｉｎｕｍｆｏｉｌｓｉｎｓｕｌｐｈｕｒｉｃａｃｉｄａｎｄｆｅｅｄｉｎｇｈｙｄｒｏｇｅｎａｎｄｏｘｙｇｅｎｓｅｐａｒａｔｅｌｙｔｏｔｈｅｅｌｅｃｔｒｏｄｅｓ .Ｔｈｅｂａｓｉｃｅｌｅｃｔｒｏｃｈｅｍｉｃａｌｒｅａｃｔｉｏｎｗａｓｓｉｍｐｌｅ :Ａｎｏｄｉｃｒｅａｃｔｉｏｎ :Ｈ2 2Ｈ+ + 2ｅ-Ｃａｔｈｏｄｉｃｒｅａｃｔ…     

SCR Drives?AC Line Disturbance, Isolation, and Short-Circuit Protection

In just eleven years, 1962-1973, adjustable-speed drives based on the SCR have progressed from zero to perhaps 80 percent of the market. Their real advantages are incontestable, high performance, efficiency, and reliability versus low cost, weight, size, and maintenance. But compatibility of the SCR drives with the ac line has become a live subject, to be covered in three parts in this paper. 1) AC line disturbance discusses the effects of the SCR drives on the ac line. 2) Short-circuit protection describes the adverse effects large power systems can have on SCR drives unless proper precautions are taken. 3) Isolation by means of a transformer is sometimes desirable to minimize these effects.     

Integrated Design,Construction and Debugging of Project

l.IntroduchonThec0nstructiontroopsofNEPGaredistributedoverHeilongjiang,JilinandLia0ningprovinces.Itiscomposedof3electricP0wersurveyanddesigninstitutes,l2thermalpowerconstructioncompanies,3powertransmissionandsubstationprOjectcompaniesand3e1ectricpowerscientificinstitutesf0rregulati0nandtesting.TheclassificationofallconsttuctionentefPrlsesareallthefirstrateofChinaandl3ofthemareamongthe500constructionenterpriseswhichhavethelargestecon0micscaleandthebestecon0micbenefit.Thesurvevanddesigninst…     

Sulfur Dioxide Emission Control, Blockade and Drainage

This paper presents the present status of sulfur dioxide emission from thermal plants in China, tells the main problems existing in its emission control and finally gives out suggestions to the problems, that is, to constitute complete standards and regulations and enhance supervision accordingly.     

The cascade development scheme of the Hongshui River Tapping the nation''''s wealth of rivers,from Yangtze,Yellow River to Hongshui River Cooperation from Hongkong,Macao,Taiwan and abroad in terms of loans,provision of equipment and technology,and investmen

China is very rich in hydropower resources.The country's theoreticalpotential is 680 GW,of which the exploitable is 380 GW,correspond-ing to an annual electricity generation of 1923 TWh.But the installedhydropower capacity is only 36,900 MW through 1989 with an electricitygeneration of 114 TWh.Together with the 12,000 MW of hydropowerstation under construction,the total hydropower exploited is still onlyabout 13% of the exploitable.In order to speed up the hydropower construction,Chinese governmenthas mapped out the development strategy for hydropower.Efforts shouldbe concentrated on continuous cascade exploitation of some river sections     

Can bottlenecks on coal, power,oil and transportation be removed？

In late March and early April, information on coal price escalation was continuously arising everywhere. As the largest coal producing province, Shanxi Province has also burst out a critical situation of coal supply. The coal price in Shanxi,Shandong etc. has escalated by 10 to 30 yuan per ton of coal.The price ofoil products nationwide rose 8% on April 1st,this price adjustment is the highest in recent years.     

Thermoelectric properties of rare earth doped Ca3-xRExCo4O9 (RE = Dy,Er, Gd,and Tb; x = 0, 0.01, 0.03, and 0.05)

Ca_3-xRE_xCo₄O₉ thermoelectric ceramics with different rare earth (RE = Dy, Er, Gd, and Tb) substitution for Ca have been successfully produced by the classical solid state method. All these rare earths in small proportions produce the same effects on the thermoelectric phase, reflected on a similar and significant decrease of the electrical resistivity, compared with the undoped samples. The Seebeck coefficient slightly decreases with all the studied substitutions while the power factor values appreciably increase at high temperatures for small amounts (0.01) of doping elements. Further doping produces the decrease of power factor which indicates that the optimal doping level has been determined to be 0.01 for all the tested rare earths which produces, approximately, the same improvement, around 20 % of the power factor obtained in the undoped samples at 800 °C.     

Electric Vehicle Charging Simulation Framework Considering Traffic, User, and Power Grid

The traffic and user have significant impacts on the electric vehicle (EV) charging load but are not considered in the existing research. We propose a novel integrated simulation framework considering the traffic, the user, and power grid as well as the EV traveling, parking and charging based on cellular automaton (CA). The traffic is modeled by the traffic module of the proposed framework based on CA, while the power grid and user are modeled in the EV charging module. The traffic flow, user’s charging preference, user’s charging satisfaction, and the total supply capability (TSC) in the surveyed region are considered in the proposed framework. Two cases are carried out to show the interactions between the user and power grid. It is shown that the proposed framework can accurately simulate the interactions among traffic situation, user’s behavior and TSC， which are significantly lacking in the existing research. The proposed framework is scalable in considering additional interrelated elements.     

Synthesis, electrical and thermal properties of Bi4V2−xZrxO11 (x = 0.0, 0.02, 0.06 and 0.10) ceramics

Polycrystalline ceramic samples of Bi₄V_2?xZr_xO₁₁ (x?=?0.0, 0.02, 0.06 and 0.10) have been synthesized by standard solid state reaction method using high purity oxides. The formation of the compounds have been checked by X-ray diffraction method. The dielectric constant, dielectric loss and ac conductivity as a function of frequency and temperature have been measured. The dielectric studies indicate that the material is highly lossy and hence its ac conductivity increases with the increase of temperature. The dc conductivity of all the materials has been measured as a function of temperature from room temperature to 673 K and its activation energy was calculated using the relation σ?=?σ_oexp (?Ea/kT). The Modulated Differential Scanning Calorimetry (MDSC) has been used to investigate the effect of substitution on the heat capacity and heat flow of the compounds. The results are discussed in detail.     

The Past, Present and Future of SupplyChain Automation

Automation has gradually evolved from within the four walls of the enterprise to encompass the outside world, resulting in the drive towards the automation of relationships. Companies with the capability to use technology to automate relationships and produce new products will have a definite advantage over others.     

Interactions between electricity,energy and the national economy

Electricity and economic growth are closely linked.For most developed countries the electricity elasticity is in the order of unity,while fordeveloping countries it is generally larger than unity.Energy consumption share for electricity generation in nations' primary energy is one ofimportant indexes of electrification degree in a country.Along with the increasing of this share,the primary energy intensity of the country keepsgoing down,especially when the share is below 30-35%,so it is of more importance for developing countries.This trend holds true for China's energy situation as well.As a strategical measure for energy conservation,the share of energy con-sumption for electricity generation keeps going up to make the energy intensity going down.