• 한국응용과학기술학회지
• /
• 제38권2호
• /
• pp.608-617
• /
• 2021

이 연구의 목적은 8주간의 코어 훈련이 프리스타일 스키 선수들의 배근력, 서전트 점프, Y-자 검사 및 평형감각 조절 능력에 미치는 영향을 보고자 하였다. 14명의 프리스타일 선수를 무작위로 운동군 7명과 통제군 7명으로 분류하였다. 훈련군은 8주간의 코어 훈련을 하였고, 통제군은 일반적인 훈련을 하였다. 연구 결과 배근력과 서전트 점프에서 효과를 보였고, 집단 간 유의한 차이는 보이지 않았다. Y-자 검사의 경우 좌측 앞쪽에서 효과를 보였고, 좌·우측 좌측 후방 안쪽에서 집단 간 차이를 보였다. 종합점수의 경우 운동군은 사전의 좌·우 차이 7.5cm, 사후에서 1.66cm로 감소하였으나 통제군은 사전 3.73cm에서 사후 7.01cm로 증가한 것으로 나타났다. 평형감각 조절 능력에서는 조건 2, 5, 6에서 유의한 효과를 보였으나 집단 간의 차이는 없었다. 결론적으로, 8주간의 코어 훈련은 프리스타일 스키선수들의 자세 조절 능력에서 유익한 효과를 미치는 것으로 나타났다.

• 한국지반공학회논문집
• /
• 제22권5호
• /
• pp.5-12
• /
• 2006

본 연구에서는 점토질 지반의 강도를 증진시키기 위해, 일련의 동전기 현상을 이용한 주입 실험을 수행하였다. 이를 위해 실내 Bench scale 실험을 실시하여 적용성을 파악하였다. 또한 확산의 영향에 의한 지반개량효과를 파악하기 위해 실험 종료 후 5일 간격으로 25일 동안 데인 실험을 실시하여 강도증진효과를 파악하였으며, 처리기간에 따른 영향을 고려하기 위해 5일 간격(5, 10, 15, 20, 25)으로 처리기간을 설정한 후 동전기 주입 실험을 실시하였다. 주입제 종류에 따른 실험결과, 초기 강도치와 비교하여 약 $2\sim7$배 정도의 강도증진효과가 발생하였으며, 특히 양극에 규산나트륨을 주입하고 음극에 인산을 주입한 경우 약 7배 정도의 강도증진효과가 발생하였다. 또한 확산과 함수비 감소에 따른 강도값을 분석해본 결과 시간경과에 따라 강도 값이 일정한 값으로 수렴하는 양상을 띠었으며, 함수비 감소에 의한 강도 증가치 보다 동전기 주입과 확산에 의한 영향으로 발생되는 강도증가치가 약 $700\sim1000%$ 높게 나타났다. 처리기간에 따른 실험결과, 처리기간이 증가함에 따라 동전기 주입에 의한 강도증진효과가 크게 나타났으며, 함수비 감소에 의한 강도증가치보다 대략 $3\sim4$배 정도 높게 나타남을 파악할 수 있었다.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2005년도 춘계 학술발표회 논문집
• /
• pp.910-915
• /
• 2005

In this study a series of tests(bench scale test) are carried out for increasing in strength of clayey soil by EK-Injection method. In addition, the effects of strength increase in the treated sample are measured by operating the vane shear test device during 25 days at 5 days intervals in order to estimate the effect of ground improvement caused by diffusion. The test results show that the strength increase was developed approximately double to 7 times in comparison to initial shear strength, and outstanding strength increase was created as much as 7 times while injecting the sodium silicate and phosphoric acid in anolyte and catholyte. In addition, the measured shear strength with the influence of diffusion and reduction of water-content had a tendency to converge in constant value in proportion to elapsed time. As a result of this study, strength increment developed by the influence of EK-Injection and diffusion rather than the reduction of water-content were high as 1000% on average

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 추계학술대회논문집B
• /
• pp.921-927
• /
• 2001

Steady flow bench test is a practical, powerful and widely used test in most engine manufacturers to give a design concept of a new engine. In order to use steady data as a performance index, it is necessary to build some database, which can correlate the port characteristics with engine data. However, it is very hard to investigate all port and valve shapes with experimental tools. The steady flow scheme is relatively simple and its results are bulk ones such as flow rate and momentum of flow. Therefore a CFD code can be easily applied to the port evaluation. In this study, the steady flow test was simulated through two and three-dimensional analysis on intake port design for comparing with experimental data and confirming the feasibility of applying analytic method. For this purpose, the effect of valve curvature on flow rate was estimated by a CFD code. There results were compared with those of real steady flow tests. As a result, the 2-D analysis described the phenomena qualitatively well, and also the results of 3-D analysis were almost consistent with experimental data.

• 한국정밀공학회지
• /
• 제32권7호
• /
• pp.603-609
• /
• 2015

Railway vehicles driven by wheels obtain force required for propulsion and braking by adhesive force between wheels and rails, this adhesive force is determined by multiplying adhesion coefficient of the friction surface by the applied axle load. Because the adhesion coefficient has a peak at certain slip velocity, it is important to determine the maximum values of the friction coefficient on the contact area. But this adhesive phenomenon is not clearly examined or analyzed. Thus we have developed new test procedure using the scaled adhesion test-bench for analyzing of the adhesion coefficient between wheel and rail. This adhesion test equipment is an experimental device that contacts mutually with twin disc which are equivalent to wheels and rails of railway vehicles.

• 자원환경지질
• /
• 제34권3호
• /
• pp.307-313
• /
• 2001

$Fe^0$ 등의 0가 금속을 포함하는 반응재들은 오염운이 반응벽을 통과하는 동안 염소계 용매들을 분해시킨다. Fe$^{0}$ 를 이용한 투수성 반응벽은 특히 trichloroethene(TCE)이 주된 오염원인 경우 처리비용이 적다는 장점이 있는 반면, 반응속도가 느리고, 반응벽의 운영기간이 제한된다는 단점이 있다. 본 연구는 기존의 Fe$^{0}$ 를 이용한 반응벽에 직류전원을 걸어주는 향상된 처리기술 개발은 예비연구이다. $Fe^0$ 반응컬럼을 이용한 bench-scale의 실험을 통해 $Fe^0$ 반응재와 직류전원의 조합은 TCE의 탈염소화를 촉진하는 것으로 나타났다. 탈염소화의 반응기작은 철의 산화와 부가적인 전자의 공급원인 외부전원에 의한 환원에 기인한다.

• 설비공학논문집
• /
• 제22권12호
• /
• pp.837-844
• /
• 2010

In this study, performance of R1234yf and R1234yf/R134a mixture is measured on a heat pump bench tester in an attempt to substitute R134a used widely in mobile air conditioners (MACs). The bench tester is equipped with a open type compressor providing a nominal capacity of 3.5 kW. All tests are conducted under the summer cooling and winter heating conditions of 7/4 $5^{\circ}C$ and $-7/41^{\circ}C$ in the evaporator and condenser, respectively. For R1234yf/R134a mixture, measurements are made at 5%, 10%, and 15% of R134a by mass. Test results show that the coefficient of performance (COP) and capacity of R1234yf are up to 2.7% and 4.0% lower than those of R134a, respectively. For R1234yf/R134a mixture, the COP and capacity are up to 3.9% lower and 3.6% higher than those of R134a. For R1234yf and R1234yf/R134a mixture, the compressor discharge temperature is $4.1{\sim}6.7^{\circ}C$ lower than that of R134a while the amount of charge is reduced up to 11% as compared to R134a. 90%R1234yf/10%R134a is a better refrigerant than pure R1234yf in that it is less flammable and more compatible with existing R134a system. Based upon the results, it is concluded that R1234yf and R1234yf/R134a mixture are long term environmentally friendly solutions to mobile air-conditioners due to their excellent environmental properties with acceptable performance.

• Tribology and Lubricants
• /
• 제25권6호
• /
• pp.432-437
• /
• 2009

The effect of oxidation in SAE 5W30 engine oils on friction and wear characteristics was investigated using reciprocating bench tester and shell 4-ball tester. Commercial engine oils were collected and oxidized using the KS M 2021 method modifying the oxidation time. Kinematic viscosity, total acid number(TAN), FT-IR spectrum and total base number(TBN) also measured to examine the chemical change of oils with oxidation. The results showed that TAN was slightly changed and Kinematic viscosity was suddenly increased during the oxidation stage. however, TBN results keep a constant slope after TBN linearly decreased with oxidation time. Spectroscopy results showed that spectrums were orderly increased at $1710cm^{-1}$ during the oxidation time. Friction test results showed that oxidation of oils formed unstable friction layers causing higher fluctuating friction. however, the wear resistance was independent of oxidized time due to the different friction characteristics by oxidation. We found several factors in relation to lubrication properties with oxidation time. This factors were Viscosity, TBN, change of FT-IR spectrum, friction coefficient using reciprocating bench tester and wear scar.

• 대한전자공학회논문지SD
• /
• 제41권7호
• /
• pp.13-20
• /
• 2004

미세 광학 벤치의 설계를 위해서 두 가지 테스트 벤치에 대해 결합효율을 계산하였다. 광섬유로 들어오고 나가게 되는 빛을 볼 렌즈를 통과한 것과 그렇지 않은 것으로 설계하였다. 미세 광학 벤치의 실제 제작 과정에서 발생할 수 있는 광소자들의 위치 에러를 고려하여 시뮬레이션을 하였고, 그것들의 허용오차를 -3 ㏈ 조건으로 정하였다. 볼 렌즈가 없는 fiber-to-fiber에서는 lateral misalignment가 2.7 um 그리고 tilt 에러가 5.8o 이내로 나타났다. 각각의 광섬유 앞단에 광의 집속을 위해 볼 렌즈가 놓여지면 working distance는 60 um로 확장되어지나, 각각의 광소자들이 놓여진 위치 파라미터 사이에 보다 강한 교호작용이 존재하기 때문에 tolerance design을 위해 교호작용을 함께 고려해야 한다.

• 의료법학
• /
• 제14권2호
• /
• pp.173-214
• /
• 2013

Traditionally, the Supreme Court has held that medical treatment agreements covered by national health insurance should be distinguished from other medical treatment agreements which are viewed as a consummation of the autonomous free will between doctor and patient. Namely, the Supreme Court views medical treatment agreements covered by national health insurance to be bound by the National Health Insurance Law with the intent to promote the applicability and comprehensiveness of the national health insurance scheme. Yet, issues of voluntary non-reimbursable treatments are triggered not only by the mistakes or moral hazard of medical care institutions but also by systemic limitations of national health insurance coverage criteria. Thus, there is a need for legislative measures that allow certain medical treatments to be included or reflected in the national health insurance coverage system so that patients may receive prompt and flexible medical treatments. To reflect such concerns, the Supreme Court made an exception for voluntary non-reimbursable treatments and developed a strict test to be applied in such cases in Supreme Court Judgment 2010 Doo 27639, 27646 (ruled on June 8, 2012 by the Grand Bench). Such judgment, however, is not a fundamental overturn of the Supreme Court's prior rulings that voluntary non-reimbursable treatments are not allowed under the law. It is only a slight revision of its previous stance for cases in which there is a lack of legislative measures to make coverage of a new yet valid medical treatment possible under the current national health insurance coverage system.