Search Results

You are looking at 1 - 10 of 63 items for

  • Author: Yu Chen x
Clear All Modify Search
Open access

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

Chen Wang, Guidong Yu, Wei Sun and Jinde Cao

Abstract

The adjacency matrix of a graph is a matrix which represents adjacent relation between the vertices of the graph. Its minimum eigenvalue is defined as the least eigenvalue of the graph. Let Gn be the set of the graphs of order n, whose complements are connected and have pendent paths. This paper investigates the least eigenvalue of the graphs and characterizes the unique graph which has the minimum least eigenvalue in Gn.

Open access

Xiaodong Chen and Yang Yu

Abstract

This study aimed at providing a reference for the selection of energy tonics for sportsmen engaging in high-strength training and competitions by investigating the effects of the intake of beverages containing glycerinum before exercise at high temperature on the physical functions of bicyclists. Forty bicyclists were selected as research subjects and divided into a test group and a control group. The indexes such as urine volume, weight loss value, oxyhemoglobin saturation, blood lactic acid, nervous tension difference value and reaction time were detected after the sportsmen took different beverages. The conclusions were drawn after the data were analyzed by SPSS ver. 18.0. The research results demonstrated that, the intake of beverages containing glycerinum could reduce urine output and lower weight loss value, prolong the endurance riding time of bicyclists in high temperature environment, reduce the concentration of blood lactic acid, improve the aerobic exercise ability of sportsmen, relieve nervous tension and fatigue, and improve physical functions.