• PNF and Movement
• /
• 제16권1호
• /
• pp.125-132
• /
• 2018

Purpose: The aim of this study was to investigate the isolated activation ratio of the quadriceps femoris muscle on different support surfaces during squat exercise. Methods: Twenty participants (10 males and 10 females) voluntarily agreed to participate in the research after receiving an explanation about the purpose and process of the study. Each participant performed squat exercises on three different support surfaces (a flat surface, a form roller, and an unstable surface). Muscle activities of the rectus femoris (RF), vastus medialis (VM), and vastus lateralis (VL) were measured by electromyography. The isolated activation ratio of the quadriceps femoris muscle was calculated using the %isolation formula. Results: For the squat exercise, the %isolation value of the VM was significantly higher on the unstable surface than on the flat surface and form roller. In contrast, the %isolation values for the RF for the squat exercise were significantly higher on the flat surface and form roller than on the unstable surface. There was no significant differences in the %isolation values of the VL on the three different surfaces. Conclusion: The findings indicate that squat exercise on different surfaces results in differential activation of the quadriceps femoris muscle, which suggests that squat exercise on a multi-directional unstable surface could increase the isolated activation ratio of the VM.

• Bulletin of the Korean Chemical Society
• /
• 제16권11호
• /
• pp.1028-1032
• /
• 1995

The structure and electronic properties of the Si(100) surface is studied using the atom superposition and electron delocalization method. The energy released when the symmetric dimer surface is reconstructed to form the buckled dimer surface with p(2X2) symmetry is calculated to be 0.99 eV per dimer in the case of ideal clean surfaces. This indicates that the surface dimer buckling is intrinsic from the viewpoint of thermodynamics. The relaxation energy, when water is adsorbed on the clean symmetric dimer surface to form the buckled dimer surface, is 2.25 eV per dimer for appropriate coverages. These results show that H2O molecule could induce a reconstruction of the surface structure through adsorption. The buckling of the surface dimer is, therefore, more favorable under the existence of water vapour. This conclusion supports the recently obtained experimental observations by Chander et al.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2004년도 학술.기술논문발표회
• /
• pp.109-112
• /
• 2004

Contemporary, architecture calls for a wide range of surface textures and treatments. A surface compatible with the architecture's design may vary from a glass-smooth finish to one requiring special sculptured ornamentation. These surfaces require many different types of form sheathing and lining. The purpose, of study development new design form and made elaborateness shape. Easy to used in field that architecture finish material not used expect effective reduce of working hours, personnel expenses, architecture finish material, cost, through this study, we have figured out the best mix proportion for durability and glossability of glossing exposure concrete.

• 제어로봇시스템학회논문지
• /
• 제15권8호
• /
• pp.812-817
• /
• 2009

In this paper, a new method to design sliding surfaces using eigenstructure assignment is proposed. Most conventional methods for constructing the surfaces require special form like canonical or regular canonical form of system matrices. But the proposed method can be applied to arbitrary system matrices. Futhermore, the surface matrix, C can be decided for the matrix multiplication, CB to have a designated form. SVD is used to decide desirable eigenvectors explicitly. To verify the proposed algorithm, a sliding mode controller for a multivariable system with matched uncertainty is constructed. The controller is designed to guarantee minimum approach velocity to the sliding surface.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 춘계학술대회 논문집
• /
• pp.1048-1051
• /
• 2001

This paper presents an analytical and experimental study of a cryogenic machining for precision hard turning. A cryogenic circulation system is designed and mounted on the top of the tool insert. The machining process used is facing operation on a CNC turning center with dry and cryogenic conditions. The tool temperature and cutting forces are measured by the K-type thermocouple and by a three-component Kistler dynamometer, respectively. Both data are fed into the data acquisition program through an A/D card. Surface roughness and form accuracy of the machined surface are measured by WYKO NT2000. It is also found that surface roughness and form accuracy with cryogenic cooling are better than those with no coolant.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 2000년도 춘계공동학술대회 논문집
• /
• pp.389-392
• /
• 2000

Gouge-free tool-path generation is an important issue in mold & die machining and researches on cutter interference avoidance can be found in many articles. One of the various methods is construction of tool-offlet surface or cutter-location (CL) surface on which the cutter-center point (CL-point) locates. Provided that the CL surface is represented in a suitable form, cutter-interference avoidance can be performed without the burden of computing CL data for every cutter-contact (CC) point. In the paper, various methods of constructing a CL surface in the z-map form are presented, where z-map is a special form of discrete nonparametric representation in which the height values at grid points on the xy-plane are stored as a 2D array z［i,j］.

• 대한산업공학회지
• /
• 제26권4호
• /
• pp.325-335
• /
• 2000

Gouge-free tool-path generation is an important issue in mold & die machining and researches on cutter interference avoidance can be found in many articles. One of the various methods is construction of tool-offset surface of cutter-location (CL) surface on which the cutter-center point (CL-point) locates. Provided that the CL surface is represented in a suitable form, cutter-interference avoidance can be performed without the burden of computing CL data for every cutter-contact (CC) point. In the paper, various methods of constructing a CL surface in the z-map form are presented, where z-map is a special form of discrete nonparametric representation in which the height values at grid points on the xy-plane are stored as a 2D array z[i,j].

• 대한조선학회논문집
• /
• 제42권5호
• /
• pp.506-515
• /
• 2005

Novel ships are commonly required iterative hull form modifications until she get reputation for new marine environment. Small FRP boats are manufactured in a identical shape with a mould. It implies that every modification step requires great time and expense which makes it difficult to improve the hull form promptly. Domestic hull form of small fishing boat of force has been evolved from the traditional hull form of developable shape. Utilizing this typical developable characteristics of small boats, ,New mouldless production method for FRP boat has been suggested and it is confirmed that the method is recommendable for a petty order of hull in evolving period of hull form development.

• 한국공간구조학회논문집
• /
• 제12권1호
• /
• pp.77-85
• /
• 2012

막 구조물은 연성의 막에 초기 장력을 주고 외관의 강성을 늘림으로써 외부하중에 안정된 형태를 유지하는 구조물로 두께를 얇게 하여 대공간 구조에 많이 채택된다. 이러한 막 구조는 자유로운 곡선을 표현할 수 있는 특성이 있어, 구조적 형태의 선정은 매우 중요하다. 이에 본 논문에서는 넙스를 기저함수로 하는 비정형 곡면으로 형상을 표현하고, 최적의 곡면 형상 탐색을 위한 대변형 결과값 도출을 위해 기하학적 비선형을 고려한 유한요소해석법을 제안하였다. 또한, 형상 탐색 결과로 나타난 곡면의 형상 근사화의 최소화를 위해 유한 요소망으로 표현된 최종 형상을 다시 넙스로 구현하는 인터페이스 기법을 제안하여, 비정형 막 구조물의 최적 곡면을 표현하였다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2008년도 추계학술대회 논문집
• /
• pp.3-4
• /
• 2008