• 한국수산과학회지
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• 제30권2호
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• pp.188-202
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• 1997

본 연구에서는 한국 동해에서의 바람장의 공간적인 분포특성을 정량적으로 파악하기 위하여 해면기압과 해상풍 자료에 EOF 분석방법을 적용하여 모드별로 고유함수의 공간적인 분포특성과 시간계수를 계산하였고 시간계수의 스펙트럼을 구하여 바람장의 공간 및 시간변동성 및 주기적인 특성을 파악하였다. 평균기압의 분포는 서고동저형의 등압선 배치를 나타내며, 기압의 최대 표준 편차는 블라디보스톡 부근에 위치하고 일본연안으로 갈수록 최저 표준편차를 갖는다. 블라디보스톡 부근은 $6.5^{\circ}C$의 해수면 온도의 최대 표준편차를 갖는 지역이기도 하다. 동서성분 해상풍의 제1모드는 분산의 $47.3\%$ 제2모드는 $30\%$를 반영하며 제1모드는 블라디보스톡 해역에서 최대 변화를 보이며 1년 및 6개월의 주기를 갖는다. 특히 제2모드에서 6개월의 주기가 탁월하다. 해상풍의 남북성분의 연평균 분포는 동해전역에서 북풍계열의 바람이 탁월하며, 특히 블라디보스톡 부근에서 최대 2.2m/s 이상의 북풍이 존재하고 3.8m/s의 표준편차 최대치가 존재하며 시간변동이 크다. 해수면 수온의 공간분포 역시 블라디보스톡 해역에서 최대치가 나타난다. 해상풍과 해면 기압의 결합 직교함수의 모드별 특성은 개별 직교함수에 비해 동서성분 해상풍의 제1모드의 기여도가 증가 하였으며, 제2모드의 기여도는 감소하는 양상을 띤다. 이로 인해 동서성분 해상풍과 해면기압의 결합 직교함수 (WU-PR)의 주기성은 해면 기압의 영향으로 제1모드에서는 1년 및 6개월의 주기가 탁월하며, 제2모드에서는 3개월의 계절변화로 해상풍의 개별 직교함수의 주기와 다르게 나타난다. 해수면 온도의 직교함수까지 포함한 3개의 결합 직교함수의 EOF분석에서는 제2모드에서 해상풍의 공간분포는 해수면 온도에 좌우되는 양상을 보인다. 스펙트럼 분석결과는 제1모드에서 1년 주기가 탁월하며 제2모드는 3개월 및 4개월의 계절변화가 나타난다.

• 한국운동역학회지
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• 제14권3호
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• pp.67-82
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• 2004

The purpose of this study was to evaluate the function and the safety of an additional weight shoe developed for the improvement of aerobic capacity, and to improve some problems found by subject's test for an additional weight shoe. The subjects employed for this study were 10 college students. 4 video cameras, AMTI force platform and Pedar insole pressure distribution measurement device were used to analyze foot motions. The results of the study were as follows: 1 The initial achilles tendon angle and initial rearfoot pronation angle of an additional weight shoe during walking were 183.7 deg and 2.33 deg, respectively, and smaller than a barefoot condition. Maximum achilles tendon angle and the angular displacement of achilles tendon angle were 185.35 deg and 4.21 deg respectively, and smaller than barefoot condition. Thus rearfoot stability variables were within the permission value for safety. 2. Maximal anterior posterior ground reaction force of additional weight shoe was appeared to be 1.01-1.2 B.W., and was bigger than a barefoot condition. The time to MAPGRF of an additional weight shoe was longer than a barefoot condition. Maximal vertical ground reaction force of additional weight shoe was appeared to be 2.3-2.7 B.W., and was bigger than a barefoot condition in propulsive force region. But A barefoot condition was bigger in braking force region. The time to MVGRF of an additional weight shoe was longer than a barefoot condition. 3. Regional peak pressure was bigger in medial region than in lateral region in contrast to conventional running shoes. The instant of regional peak pressure was M1-M2-M7-M4-M6-M5 -M3, and differed form conventional running shoes. Regional Impulse was shown to be abnormal patterns. There were no evidences that an additional weight shoe would have function and safety problems through the analysis of rearfoot control and ground reaction force during walking. However, There appeared to have small problem in pressure distribution. It was considered that it would be possible to redesign the inner geometry. This study could not find out safety on human body and exercise effects because of short term research period. Therefore long term study on subject's test would be necessary in the future study.

• Journal of Mechanical Science and Technology
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• 제15권4호
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• pp.482-491
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• 2001

An experimental study has been carried out to investigate an I-type sparger-performance in view of pressure oscillation and thermal mixing in a pool. Its pitch-to-hole diameter, P/D, varies from 2 to 5. The test conditions are restricted to the condensation oscillation regime. In the present study, two different hole patterns, staggered and parallel types, are employed under various test conditions. The amplitude of the pressure pulse shows a peak for pool temperatures of 45∼85$\^{C}$, which depends on P/D and the steam mass flux. The effect of hole pattern on the pressure load is smaller than that of P/D. The dominant frequency increases with the subcooling temperature of pool water and P/D. A correlation for the dominant frequency is proposed in terms of the pitch-to-hole diameter ratio and other dimensionless thermal hydraulic parameters.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권3호
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• pp.149-154
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• 2000

Bi-layer Mo films were deposited on soda-lime glass substrates using DC magnetron supttering. Increasing gas pressure, the resistivity varied from $1\times10^{-5}\; to\; 8.3\times10^{-3}\; \Omega.cm$. Furthermore, stress direction yielded compressive-to-tensile transition stress curves. The micro-structure of the compressively-stressed film which had poor adhesion consists of tightly packed columns, but of the tensile-stressed films had less dense structure. Under all gas pressure conditions, Mo films exhibited distinctly increasing optical reflection with decreasing gas pressure. The expansion of (110) peak width with the gas pressure meant the worse crystalline growth. The impurity levels in the Mo film exhibited highly concentrated Na, Se and O elements due to less dense micro-structure. The degree of Na diffusion depends on the type of the glass substrate used and the nature of the Mo film.

• Wind and Structures
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• 제16권1호
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• pp.117-136
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• 2013

A field study of wind-induced internal pressures in a flexible and porous industrial warehouse with a single dominant opening, of various sizes for a range of moderate wind speeds and directions, is reported in this paper. Comparatively weak resonance of internal pressure for oblique windward opening situations, and hardly discernible at other wind directions, is attributed to the inherent leakage and flexibility in the envelope of the building in addition to the moderate wind speeds encountered during the tests. The measured internal pressures agree well with the theoretical predictions obtained by numerically simulating the analytical model of internal pressure for a porous and flexible building with a dominant opening. Ratios of the RMS and peak internal to opening external pressures obtained in the study are presented in a non-dimensional format along with other published full scale measurements and compared with the non-dimensional design equation proposed in recent literature.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.649-653
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• 2006

Engine Noise is composed of the mechanical and combustion noise. The contribution of combustion noise is generally bigger than the contribution of the mechanical noise at idle condition in DI diesel engine. That noise usually makes a roughness problem at the fundamental engine order. It is difficult to remove the modulation frequency so we have to directly reduce the combustion noise. The key effect of combustion noise reducing solution is the modification of the combustion pressure profile. It is accomplished by the multiple injection method and we solved the 400Hz combustion noise and improved the sound quality at idle condition in DI diesel engine.

• Biomolecules & Therapeutics
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• 제10권2호
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• pp.89-98
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• 2002

In this study general pharmacological profiles of KI-60606 on the central nervous system, the cardiovascular system and the other organs were investigated. The dosages given were 0,5, 10 and 25 mg/kg and drugs were administered intravenously. The animals used for this study were mice, rats, cats and guinea pigs. KI-60606 showed no effects on general behavior, motor coordination, spontaneous locomotor activity, hexobarbital-induced hypnosis time, body temperature, analgesic activity, anticonvulsant activity and contraction of nictitating membrane in cats. Furthermore KI-60606 showed no effects on blood pressure, heart rate, LVP (left ventricular peak systolic pressure), LVEDP (left ventricular end diastolic pressure), LVDP (left ventricular developing pressure), DP(double product), CFR(coronary flow rate), smooth muscle contraction using guinea pig ileum and gastric secretion at all dosage tested except the increase of gastrointestinal transport and urinary $K^+$ excretion.

• Wind and Structures
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• 제30권3호
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• pp.299-316
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• 2020

Based on wind tunnel tests, this paper investigates the aerodynamic behavior of a large span canopy roof with elliptical plan and hyperbolic paraboloid shape. The statistics of pressure coefficients and the peak factor distributions are calculated for the top and bottom faces of the roof, and the Gaussian or non-Gaussian characteristics of the pressure time-histories in different areas of the roof are discussed. The cross-correlation of pressures at different positions on the roof, and between the top and bottom faces is also investigated. Combination factors are also evaluated to take into account the extreme values of net loads, relevant to the structural design of canopies.

• Tribology and Lubricants
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• 제12권3호
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• pp.63-71
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• 1996

The connecting rod bearing, which is subjected to periodical dynamic loading, is an impoRant component of the reciprocating engine. In the operation of this bearing, significant parameters are the oil film thickness and the film pressure. Peak film pressures of 20-30 MPa are not uncommon. So the elastic deformation of the bearing housing can have a significant effect on the bearing performance. In this study, a numerical analysis of connecting rod bearing is investigated. Elastic deformation of the bearing housing is considered in the analysis. Separate hydrodynamic and structural analysis are coupled through a direct iterative process. It is shown that as the result of the elastic deformation of the bearing housing, the eccentricity ratio is increased, and the minimum value of the minimum film thickness and the maximum value of the maximum film pressure are decreased. The variations of rotational speed and cylinder pressure affect the minimum film thickness and the maximum film pressure variations of the connecting rod bearing.

• 유공압시스템학회논문집
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• 제5권2호
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• pp.14-19
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• 2008

Hydraulic excavator consists of booms, arms, bucket, and cylinder. The cylinder make these structures moved and the cushion parts of cylinder in operation absorb the great impact which is stemmed from high velocity and pressure at cushion parts of cylinders. The cushion technology of cylinders has a great effect on the operator's comfortable as well as protecting equipment from damage by suppressing the inertia of the hydraulic excavator. In this study, three hydraulic cylinders have different shapes of a cushion ring, respectively. we studied optimal cushion pattern by analyzing the change of cushion pressure and time, according to supply pressure and velocity variations.