共查询到10条相似文献，搜索用时 312 毫秒
1.
A. VALAN ARASU T. SORNAKUMAR 《浙江大学学报(A卷英文版)》2008,9(3):416-422
Parabolic trough collectors （PTCs） are employed for a variety of applications including steam generation and hot water generation. This paper deals with the experimental results and an economic analysis of a new fibre reinforced plastic （FRP） based solar PTC with an embedded electronic controlled tracking system designed and developed for hot water generation in a restaurant in Madurai, India. The new collector performance has been tested according to ASHRAE Standard 93 （1986）. The performance of a new PTC hot water generation system with a well mixed hot water storage tank is investigated by a series of extensive tests over ten months period. The average maximum storage tank water temperature observed was 74.91℃, when no energy is withdrawn from the tank to the load during the collection period. The total cost of the new economic FRP based solar PTC for hot water generation with an embedded electronic controlled tracking system is Rs. 25000 （US$ 573） only. In the present work, life cycle savings （LCS） method is employed for a detailed economic analysis of the PTC system. A computer program is used as a tool for the economic analysis. The present worth of life cycle solar savings is evaluated for the new solar PTC hot water generation system that replaces an existing electric water heating system in the restaurant and attains a value of Rs. 23171.66 after 15 years, which is a significant saving. The LCS method and the MATLAB computer simulation program presented in this paper can be used to estimate the LCS of other renewable energy systems. 相似文献
2.
A graphical and visual simulation system for the study of optical packet switching(OPS)nodes is accomplished.With the simulation system,the effect on physical performance-bit error rate(BER)due to a variety of factors such as the crosstalk parameters of OPS nodes,number of cascaded OPS nodes,length of optical output buffer,traffic load and fluctuation of amplitude of optical signals are evaluated.Reliability of the simulation system is proved by the analytical results obtained in all the above cases. 相似文献
3.
A CAD／CAE system of the ring-type planetary reducer with small tooth number difference is presented.It is a parameterized CAD/CAE system adopting the object-oriented technique and comprising in itself the geometric feature database(including the modules of ring-plates with ineer te4eth,eccentric shaft modules and output shaft modules),standard componentdatabase and material database.In cdomparison with design by handwork,this computer aided design and analysis system has the advantages of improved quality,shortened design period and reduced cost.The reliability of the system has been verified by a illustrative example. 相似文献
4.
邢连香 《山西教育(综合版)》2006,(1)
The exam system has come to be the main topic of modern education.As it plays so important a role in the area of education that it is under much discussion as to its use.People who are for it try to develop this system more;those who are against it believe that such a system should be stopped.Should exam be stopped?In my opinion it should be.Firstly,a number of people think that an exam is the only way to test knowledge,but,in fact,that is not true.A few questions given in an exam could in no… 相似文献
5.
朱惠凤 《初中生世界(初三物理版)》2002,(18)
一、1.许多老师正在听演讲。误:A number of teachers is listening to thelecture.正:A number of teachers are listening to thelecture.2.这个工厂里的工人数是800.误:The number of the workers in this factoryare eight hundred.正:The number of the worders in this factoy iseight hundred. 相似文献
6.
An acoustic pressure amplifier （APA） is capable of improving the match between a thermoacoustic engine and a load by elevating pressure ratio and acoustic power output. A standing-wave thermoacoustic engine driving a resistance- and-compliance （RC） load through an APA was simulated with linear thermoacoustics to study the impact of load impedance on the performance of the thermoacoustic system. Based on the simulation results, analysis focuses on the distribution of pressure amplitude and velocity amplitude in APA with an RC load of diverse acoustic resistances and compliance impedances. Variation of operating parameters, including pressure ratio, acoustic power, hot end temperature of stack, etc., versus impedance of the RC load is presented and analyzed according to the abovementioned distribution. A verifying experiment has been performed, which indicates that the simulation can roughly predict the system operation in the fundamental-frequency mode. 相似文献
7.
The related existing energy saving index system of buildings is deficient in direction, index coverage, depth, and technological and economic considerations. Aiming at the deficient existing research and with the advancement of energy saving of buildings in China from northern heating regions to southern hot summer and cold winter regions, selecting residential buildings in hot summer and cold winter regions as the research object, and through much evaluation index reference and repeated demonstrations and the borrowing of literature research home and abroad and relevant energy saving standards, filters and eliminates energy efficient technologies evaluation indexes according to the design principle of index system, the factors influencing the energy saving of residential buildings are evaluated, index system weight is established by adopting analytic hierarchy process, and finally the evaluation index system of energy saving technologies of residential buildings in hot summer and cold winter area of China is established. Each target layer includes five standard layer indexes and sixteen index layer indexes The standard layer of evaluation index, namely primary indexes, includes the technological, energy saving effect, economic, environmental, and social indexes. The secondary indexes are selected based on the principles of concision, comprehensiveness, representativeness and operability. 相似文献
8.
喻安民 《中学英语园地(高三版)》2005,(10)
1.In our city,its in July,but its even in A ugust.A .hotter;hottest B .hot;hotC.hotter;hor D .hot;hotter2.Of the two A ustralian students,Masha is one.I think you canfind her easily.A .tallest B.the taller C .taller D .the tallest3.The population of Shanghai is than thatofShijiazhuang.A .sm aller B.larger C .less D .large4.W hich subject do you think is ,physics or chem istry?A .interesting B .m ostinterestingC.m ore interesting D .the m ostinteresting5.Jim is running B ruce.They are… 相似文献
9.
ZOU Jun FU Xin YANG Hua-yong 《浙江大学学报(A卷英文版)》2007,8(9):1429-1434
The highly nonlinear behavior of the system limits the performance of classical linear proportional and integral (PI) controllers used for hot rolling. An active disturbance rejection controller is proposed in this paper to deal with the nonlinear problem of hydraulic servo system in order to preserve fast response and small overshoot of control system. The active disturbance rejection (ADR) controller is composed of nonlinear tracking differentiator (TD),extended state observer (ESO) and nonlinear feedback (NF) law. An example of the hydraulic edger system case study is investigated to show the effectiveness and robustness of the proposed nonlinear controller,especially,in the circumstance of foreign disturbance and working condition variation,compared with classic PI controller. 相似文献
10.
1.—Could you tell me whom the radio______by?—Sorry,I have no idea(.2007福州市)A.invents B.inventedC.is invented D.was invented2.—How many students are there in your school?—______the students in our school______over twothousand.(2006青海省)A.The number of;is B.The number of;areC.A number of;is3.选择与划线部分意义相近的短语:In the end,he decided to send the sick child to hospital.(2007成都市)A.At once B.At last C.At first4.The kids didn’t start to fly kites on the playground______th… 相似文献