Lifetime Evaluation of Medium and Small Size Power Transformers—— Part 1 : Theory

ＬｉｆｅｔｉｍｅＥｖａｌｕａｔｉｏｎｏｆＭｅｄｉｕｍａｎｄＳｍａｌＳｉｚｅＰｏｗｅｒＴｒａｎｓｆｏｒｍｅｒｓ—Ｐａｒｔ１：ＴｈｅｏｒｙＧｕｏＹｏｎｇｊｉ（郭永基），ＤａｉＹｏｕｊｉｅ（代有杰）ＤｅｐａｒｔｍｅｎｔｏｆＥｌｅｃｔｒｉｃａｌＥｎｇｉｎｅｅ...     

Development of CAPP System for Small and Medium Size Apparel Enterprises

Existing computer-aided process planning （CAPP） systems for garment manufacturing emphasize all-purpose ones, lack specialism and availability. So, few developed is popular in the garment industries. This study is intended for developing a CAPP system, which aims at the actual condition of process planning in the small and medium size apparel enterprises （SMAs）. It enables the technologists of process planning to be quicker in generating suitable plans that are similar to existing styles or new. It also automatically provides labor cost by considering the shop-ricer caztiticns. Process planning is achieved by adopting the Hybrid Interactive-variant process planning mete. The proposed system has been realized in Borland Delphi 7 and Orade 8. For validation of the system, the software has been implemented successfully in a firm named Jingchen in China.     

Experimental Study of Rotor-boundary Impact and Rub

ＥｘｐｅｒｉｍｅｎｔａｌＳｔｕｄｙｏｆＲｏｔｏｒ┐ｂｏｕｎｄａｒｙＩｍｐａｃｔａｎｄＲｕｂ＊ＺｈａｎｇＸｉａｏｚｈａｎｇ（张小章），ＤａｉＸｉｎｇｊｉａｎ（戴兴建），ＬｉｕＰｉｎｇ（刘萍）ＤｅｐａｒｔｍｅｎｔｏｆＥｎｇｉｎｅｒｉｎｇＰｈｙｓｉｃｓ，Ｔ...     

Experimental Evaluation of TCP and ICMP in Network Measurement

Network measurement is an important approach to understand network behaviors, which has been widely studied. Both Transfer Control Protocol （TCP） and Interact Control Messages Protocol （ICMP） are applied in network measurement, while investigating the differences between the measured results of these two protocols is an important topic that has been less investigated. In this paper, to compare the differences between TCP and ICMP when they are used in measuring host connectivity, RTT, and packet loss rate, two groups of comparison programs have been designed, and after careful evaluation of the program parameters, a lot of comparison experiments are executed on the Internet. The experimental results show that, there are significant differences between the host connectivity measured using TCP or ICMP; in general, the accuracy of connectivity measured using TCP is 20%- 30% higher than that measured using ICMP. The case of RTT and packet loss rate is complicated, which are related to path loads and destination host loads. While commonly, the RTF and packet loss rate＂ measured using TCP or ICMP are very close. According to the experimental results, some advices are also given on protocol selection for conducting accurate connectivity, RTF and packet loss rate measurements.     

The Application of Survey Study and Experimental Study to Second Language Acquisition

Survey study and experimental study are two kinds of important methods in applied linguistics.They are typically to collect quantitative data in the research of SLA.However,they are different.This paper mainly demonstrates their application to the research of SLA through the comparative analysis of these two kinds of studies.This will offer researchers a reference which study is better for their SLA research.     

Study and Application of Objective Evaluation Model on Fabric Style

Based on 31 fabric property parameters tested by FAST test system and other test instruments, the principal factors of fabric style are obtained through the principal factor analysis method and computer program. According to the correlation between each parameter and principal factor,the selected positive or negative coefficient, the objective evaluation model of fabric style bas been established based on the percentage of variance. And wool fabrics have been taken for example to show how to use the objective evaluation model for fabric design.     

Study and Development of a Simulation System for Dynamic Evaluation on Man-machine Interface Design of Advanced Main Control Rooms of Nuclear Power Plants

Since the man-machine interfaces (MMI) of a main control room provide the control platform of a nuclear power plant (NPP),the development of the design quality of MMIs plays a very important role in the operation of a NPP. With the development of digital technology, the development of the advanced main control rooms (AMCRs) has become an inexorable trend. Therefore, the positive and the negative effects of AMCRs on human factors engineering need to be evaluated. For this p~, a simulation system has been studied and developed to quantitatively evaluate a MMI design from the viewpoint of human factors. The simulation system takes advantage of computer simulation technology to simulate an operating process of an interaction between operators and a MMI design under an instruction of an operation procedure of the AMCR of a NPP. Meanwhile, the necessary data are recorded for evaluation. It integrates two editors and one simulator. In the paper, the simulation system is presented in detail. Furthermore, one sample is given to show the results of each of these three subsystems.     

Experimental and Theoretical Study of Young Modulus in Micromachined Polysilicon Films

IntroductionThe development of microelectromechanicalsystems (MEMS) has achieved impressiveprogress with many new designs that couldpotentially lead to another industrial revolution.However,the long- term durability of the MEMSdevices,which requires a fun…     

Study on SO_2 Emission Mitigation of Thermal Power Plants in China

IntroductionWith the development of economics,Chinafaces the challenge of severe air pollution.As oneof the largest coal consumers in the world,coalaccounts for over 70 % in China's energyproduction and consumption mix,which hascaused serious SO2 and acid rain pollution in urbanareas.In 1 998,national SO2 emission was about2 0 .87Mt in China,of which87% came from coalcombustion[1] . In over 70 % cities nationwide,urban atmospheric quality violated the third classof national air quality sta…     

Superhydrophobicity on Micro-and Nanostructured Polyolefin Surfaces:an Experimental and Theoretical Study

1 Results Simultaneous micro-and nanostructuring was prepared on polyolefin surfaces by injection molding.The molds were made of electropolished aluminum foil where the micropatterns were structured with a custom made robot.Nanopatterns were subsequently created on the molds by oxidizing the aluminum surface electrochemically in polyprotic acid.The preparation technique allowed simultaneous control of the dimensions of the micro-and nanostructures.Structuring has a remarkable effect on the contact angle between the polyolefin and water.With optimized microstructure covered with nanostructure the static contact angle between polypropylene and water was found to be 165°.The sliding angle of about 2.5° proved the superhydrophobic state[1]. Molecular dynamics simulations were used to study the effect of periodic roughness of polyethylene on the hydrophobicity.Nanoscale pillars of different lateral dimensions and heights were derived from flat crystalline surfaces,and the results of simulations on the structured surfaces were compared with theoretical predictions of the Wenzel and Cassie equations[2-3].     

Study of Competitive Chelating Reaction between Lanthanum and Tribromoarsenazo in the Medium of Weak Acid by Capillary Zone Electrophoresis

Two kinds of metal chelates of rare earth elements reacted with tribrimoarsenazo formed under the condition of critic acid were observed by simultaneous technique of capillary electrophoresis-photothermal interference spectrometry. The tendency of the conversion between these chelates as functions of the mole ratio of the reagent and the metal, pH value and the elapsing time was investigated. Kinetic equation of competitive chelating reaction between the TBA-La (Ⅲ) and La (Ⅲ) -critic acid were established. It was found that the competitive chelating reaction follows second-order kinetics, for this second-order reaction, k = 5. 55 L·mol-1·S-1 .     

Experimental Study on the Feasibility of Methane Drainage in Coal Seams with Compound Technique of Perforating and Fracturing

1IntroductionGas disasters are the most main hidden dangersof coal mines,actually the ultimate means ofproblem-solvingis pre-drainage.The permeabilitycoefficient of coal seamis the parameter whichjudges the degree of difficulty or easiness of themethane flows in coal seams,which is provedright in theory and in practice.During drainingmethane,the drainage effects of coal seams,whose pressure are not relived,are mainly dependonthe permeability coefficients[1].At the presenttime,one of the key pr…     

Experimental Study on the Hydrodynamics and Mass Transfer Characteristics of Airlift Loop Reactors（ALR）

1IntroductionWhen used in the reaction system,airlift loopreactors(ALRs)have the characteristics of highmass transfer coefficient,good mixingperformance,low flow sheer stress and energysaving,and thus enjoy a broad prospect ofapplication.In additionto tra…     

Experimental Study on the Hydrodynamics and Mass Transfer Characteristics of Airlift Loop Reactors（ALR）

The promoting effect of ultrasonic wave on the hydrodynamics and mass transfer characteristics of the airlift loop reactor was studied．The effect of the airlift reactor and ultrasonic wave on the reactor’s gas holdup,liquid circulation velocity,mixing time and overall volumetric mass transfer coefficient respectively with and without the presence of ultrasonic wave is empathetically examined and compared．The experiment has proven that the incorporation of ultrasonic wave has no effect on the gas holdup but has the tendency to gradually decrease the liquid circulation velocity and increase the overall volumetric mass transfer coefficient; the effect on the mixing time is relatively complex．At low gas velocity,low powered ultrasonic wave promotes the radial mixing of fluid;with the increase of ultrasonic power,ultrasonic vibration obstructs the radial mixing of fluid．Therefore,there exists an optimal ultrasonic power．Moreover,the effect of ultrasonic wave on the mixing time gradually decreases with the increase of the superficial gas velocity．Correlations were also proposed for the hydrodynamics and mass transfer characteristics of the reactor．     

Evaluation of Eco-efficiency and Effect on Environment of Remanufacturing——A Case Study of CNC-remanufacturing for Used Machining Tools

A case of remanufacturing used lathes via CNC technology is introduced, whose environmental and economic benefits are evaluated respectively. The results indicate that these environmental and economic benefits are remarkable, which are directly affected by remanufacturing design, more than 90% materials in used lathes are reused. Finally, the causes of economic and environmental benefits of remanufacturing machine tools are put forward. The remanufacturing design method, implementation procedure, and evaluation method of economic and environmental benefits presented are helpful for other equipment remanufacturing.     

Hemingway and Fitzgerald:A Comparative Study of Their Works

Belonging to the same time in American history, Ernest Hemingway and F. Scott Fitzgerald have many similarities anddifferences in their artistic worlds. They deal with similar themes: being at a loss, death and failure. Yet the significances of theirthemes are quite different, even opposite.     

Study of droplet size and velocity of fuel containing CO2 spray by means of PDA

Injection of fuel containing CO2 has potential to reduce NOx and soot emissions in a diesel engine. This paper presents an experimental study on the spray characteristics of fuel containing CO2 as measured by phase doppler anemometry (PDA). Experiments were performed under atmospheric conditions on diesel hole-type nozzles at constant injection pressure. Effects of CO2 concentration in diesel fuel on the spray pattern, droplet size and velocity were measured. Experimental results show that fuel atomization will improve greatly when the concentration of dissolved CO2 in the fuel exceeds the critical value. The axial and radial velocity of the fuel spray containing CO2 is larger than that of conventional diesel fuel spray near the nozzle exit due to flash boiling phenomena. Downstream of the spray, the radial velocity and droplet size of fuel containing CO2 is much more uniform and smaller than that of pure diesel spray. It is attributed to the greatly enhanced liquid-gas mixing resulting from flash separation of CO2 from the liquid. New insight into the atomization of the fuel containing CO2 was obtained and a possible mechanism to explain the phenomena was proposed. The method may be developed into a new technique for controlling diesel combustion and exhaust emis-sions.     

Degrees of Affinity: A Comparative Study on English and Chinese Proverbs

ＤｅｇｒｅｅｓｏｆＡｆｆｉｎｉｔｙ：ＡＣｏｍｐａｒａｔｉｖｅＳｔｕｄｙｏｎＥｎｇｌｉｓｈａｎｄＣｈｉｎｅｓｅＰｒｏｖｅｒｂｓＧｕｉＱｉｎｇ－ｙａｎｇＤｅｇｒｅｅｓｏｆＡｆｆｉｎｉｔｙ：ＡＣｏｍｐａｒａｔｉｖｅＳｔｕｄｙｏｎＥｎｇｌｉｓｈａｎｄＣｈｉｎ...     

Electrospun Small Diameter Tubes to Mimic Mechanical Properties of Native Blood Vessels Using Poly (L-lactide-co-ε-caprolactone )and Silk Fibroin: a Preliminary Study

Mismatch in mechanical properties can induce intimal hyperplasia,which is one of the main reasons for the failure of small diameter artificial blood vessels. Electrospun small diameter tubes with tailored mechanical properties were fabricated through blending poly( L-lactide-co-ε-caprolactone)( PLCL) and silk fibroin( SF)with the mass ratios of 30 /70,50 /50,and 70 /30 in this study.Scanning electron microscopy( SEM) and mechanical testing were used to characterize morphological and mechanical properties of the tubes. Results showed that tensile strength of the tubes was higher than most of the native blood vessels,and elongations at break of them were improved greatly by blending PLCL. Compliances of the tubes were all higher than 1% /13. 33 kPa( 1% /100 mmHg).Particularly,tubes with blending mass ratio of 50 /50 showed similar compliance with human native femoral arteries,which provided a promising biomaterial that could be applied on small diameter vascular applications.     

Copolymers of Styrene with Conjugated Dienes by Titanium Catalysts:Synthesis,Characterization and Evaluation of the Mechanical Properties

1 Results Polymerization of butadiene,isoprene and styrene and binary copolymerization of styrene with butadiene and isoprene were investigated using the catalyst Ti(η5-C5H5)(η2-MBMP)Cl (1) (MBMP=2,2′-methylenebis(6-tert-butyl-4-methylphenoxo) activated with methylaluminoxane (MAO).Syndiotactic polystyrene, cis-1,4- polybutadiene and cis-1,4-polyisoprene were obtained in good yields at 50 °C.Binary copolymerization of styrene with butadiene yielded block copolymers containing segments of cis-1,4-polybutadiene and crystalline syndiotactic polystyrene. Novel pseudorandom copolymers of styrene with isoprene were synthesized using the 1/MAO catalyst.The 13C NMR chemical shifts of the carbon atoms diagnostic of the different monomer diads and triads were predicted and assigned using properly calculated additive shift factors.Despite the syndiotactic arrangement of the styrene homosequences,the styrene-co-isoprene polymers are completely soluble in organic solvents and completely amorphous also at high styrene concentration.