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Jing Yu, Liu Liu and Gong Chen

Abstract

The purpose of this study was to investigate college students on their speed of performing different types of self-defense skills commonly taught in American university self-defense courses. The results indicated that close defense skills and distance punches are faster than distance kicks in most single skills or combination skills. Women can do most skills as fast as men. The results also indicated that all kicks with back-foot are slower than kicks with front-foot in distance defense. Women need 2.42- 6.12 seconds to escape from all 20 holds, while men need 1.14-5.54 seconds for people who successfully escaped. Escaping from different holds is not as difficult as what most people think. After proper learning and practice, a majority of college women and men can escape from many holds in 1-6 seconds.

Open access

Yun-Yu Chen

Abstract

As a kind of mass transfer process as well as the basis of separating and purifying mixtures, interfacial adsorption has been widely applied to fields like chemical industry, medical industry and purification engineering in recent years. Influencing factors of interfacial adsorption, in addition to the traditional temperature, intensity of pressure, amount of substance and concentration, also include external fields, such as magnetic field, electric field and electromagnetic field, etc. Starting from the point of thermodynamics and taking the Gibbs adsorption as the model, the combination of energy axiom and the first law of thermodynamics was applied to boundary phase, and thus the theoretical expression for the volume of interface absorption under electric field as well as the mathematical relationship between surface tension and electric field intensity was obtained. In addition, according to the obtained theoretical expression, the volume of interface absorption of ethanol solution under different electric field intensities and concentrations was calculated. Moreover, the mechanism of interfacial adsorption was described from the perspective of thermodynamics and the influence of electric field on interfacial adsorption was explained reasonably, aiming to further discuss the influence of thermodynamic mechanism of interfacial adsorption on purifying air-conditioning engineering under intensification of electric field.

Open access

Gong Chen, Liu Liu and Jing Yu

A Comparative Study on Strength between American College Male and Female Students in Caucasian and Asian Populations

Muscle strength has been considered as a major factor on sport performance, martial arts competitions, self-defense, and other physical activities. The purpose of the study was to investigate potential difference on muscle strength between male and female college students. The results indicated that the muscle strength of female students is significantly lower than male students on strength of arm, upperbody and chest, shoulder, leg, and abdominal. Females have 37-68% of muscle strength of males in general. The difference on muscle strength between females and males is more on upper body, and less on lower body. Females are relatively stronger on their legs than arms and shoulders.

Open access

Wu Zhou, Lili Chen, Huijun Yu, Bei Peng and Yu Chen

Abstract

The abnormal phenomenon occurring in sensor calibration is an obstacle to product development but a useful guideline to product improvement. The sensitivity jump of micro accelerometers in the calibrating process is recognized as an important abnormal behavior and investigated in this paper. The characteristics of jumping output in the centrifuge test are theoretically and experimentally analyzed and their underlying mechanism is found to be related to the varied stiffness of supporting beam induced by the convex defect on it. The convex defect is normally formed by the lithography deviation and/or etching error and can result in a jumping stiffness of folded microbeams and further influence the sensitivity when a part of the bending beams is stopped from moving by two surfaces contacting. The jumping level depends on the location of convex and has nothing to do with the contacting properties of beam and defects. Then the location of defect is predicted by theoretical model and simulation and verified by the observation of micro structures under microscopy. The results indicate that the tested micro accelerometer has its defect on the beam with a distance of about 290μm from the border of proof mass block.

Open access

Chih-Li Chen, Tien-Pen Hsu and Guo-Yu Weng

Abstract

In this paper two new approaches are developed to calculate the astronomical vessel position (AVP). Basically, determining the AVP is originated from the spherical equal altitude circles (EACs) concept; therefore, based on the Sumner line's idea, which implies the trial-and-error procedure in assumption, the AVP is determined by using the two proposed approaches. One consists in taking the great circle of spherical geometry to replace the EAC to fix the AVP and the other implements the straight line of the plane geometry to replace the EAC to yield the AVP. To ensure the real AVP, both approaches choose the iteration scheme running in the assumed latitude interval to determine the final AVP. Several benchmark examples are demonstrated to show that the proposed approaches are more accurate and universal as compared with those conventional approaches used in the maritime education or practical operations.

Open access

Ping Du, Yan-Qiu Chen, Chang-Tian Li and Yu Li

Application of Random Amplified Polymorphic DNA Analysis in Identifying Phellinus Igniarius Strains

Described in this paper, the random amplified polymorphic DNA (RAPD) analysis was conducted with 20 random primers in various strains of Phellinus igniarius collected from different localities. The results showed that 17 of the 20 random primers were polymorphic ones. The DNA bands derived from each primer amplifying in tested strains ranged from 10 to 33. The size of the amplified DNA fragments ranged from 250 to 2000 base pairs. Of each test primer, a wide variation in banding profiles was observed among the 7 strains of P. igniarius. A total of 377 band positions were scored for all of the tested strains, which differed significantly among the bands from different primers. UPGMA cluster analysis subdivided the tested strains into two groups, which was helpful to find out the difference among the tested strains and to distinguish them directly.