• Proceedings of the KWS Conference
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• 2008.05a
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• pp.46-46
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• 2008

• Korean Journal of Optics and Photonics
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• v.11 no.4
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• pp.227-231
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• 2000

Thermal cesium atomic beam was collimated by transversely cooling of atoms, for which circularly polarized ($\sigma^+$ and $\sigma^-$ polarized) laser light was illuminated to the atomic beam from two perpendicular directions. As a result, the temperature corresponding to the transverse velocity component could be decreased from 430 mK to 60 11K. In addition, the spatial atomic distribution was observed according to the power difference of the two laser beams and the magnetic field applied, and the result was qualitatively coincided with the calculation result by the Doppler cooling theory. heory.

• Journal of ILASS-Korea
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• v.2 no.1
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• pp.18-28
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• 1997

The present study is mainly aiming at numerically analyzing the combustion and emission characteristics of the diesel spray in a high-pressure environment. Computations are peformed for the peak chamber pressure with range from 4.08 MPa to 162 MPa. Numerical results indicate that the pressure increase in combustion chamber significantly influences the mechanism for droplet dynamics and mixing characteristics, spray penetration autoignition, flame lift-on height and the propagation or fuel vapor and flame. By increasing the ratio or the ambient density to injected liquid density, the fuel-air mixing rates and the burning rates increase and the $NO_x/soot$ emission level decreases.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.820-824
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• 1997

In order to investigate the effect of surface treatment(Anodizing) and rolling in Al 5083-H131 alloy, ballistic testing was conducted. Ballistic resistance of these materials. was measured by protection ballistic limit(V$_{50}$), a statical velocity with 50% probability for incomplete penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, are observed respectfully, resulting from V$_{50}$ test and Projectile Through Plates(PTP) test at velocities greater than V$_{50}$. PTP tests were conducted with 0$^{\circ}$obliquity at room temperature were also conducted with projectiles that were able to achieve near or complete penetration during PTP tests. Resistance to penetration, and penetration modes of Al 5052-H34 alloy, compared to those of Al 5083-H131 alloy.alloy.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.6
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• pp.427-433
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• 2007

Generally, H.V.A.C load capacity in early planning phase can presume with maximum thermal load. Basic data can prove by air conditioning equipment system data analysis at existing building. There are poor and not reliable alternative presentation. In this paper, measured data after use H.V.A.C load calculation K-load program reply choosing standard building and variables simulation. And I founded peak load correlation graph and mode for several kinds of variable and contents of size. I wish that equipment designer is beaconed to produce optimum capacity at building as quantitative through this result.

• Journal of Welding and Joining
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• v.8 no.2
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• pp.53-57
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• 1990

Analytic solutions of heat conduction during welding which were first found by Resenthal have some restrictions. One of these is that models to which analytic solutions can be applied must have simple geometric shape, and another is that quasi-stationary state must be created. On the other hand, computational methods developed recently with the aid of the computer can overcome these shortcomings, but the methods raise problems from economic point of view when they are applied to 3 dimensional problems. Taking account of these problems, a new method combinig the analytic method with the computational one is proposed. This method can be ued in weldments with complicated geometric shape in non-stationary state, but with the aid of the analytic method can reduce the computing time.

• Journal of Welding and Joining
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• v.8 no.4
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• pp.58-68
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• 1990

The formation of thermal stresses by plasma spraying is generally considered as adverse. Therefore, the knowledge of stress distribution in the deposited layer during and after plasma spraying will be of special interest. In this study finite difference heat transfer analysis and finite element stress analysis were carried out to predict the change of stress distribution in the plasma coated layer with the variations of preheat temperature, number of scan, particle size, and bond coat. The results of the numerical analysis were as follows: 1) Transient stresses developed in the coated layer were up to the level of yiedl strength at the temperature. 2) The tensile stresses were developed in the deposited layer and the surface of the substrate, but the compressive stresses were developed in the rest of the substrate. 3) Transient and residual stresses were significantly affected by the preheat temperature. 4) The variations of temperature of powder particle and number of torch scan changed tensile stress distribution, but made no difference on the magnitude of the stresses. 5) Bond coated layer reduced the stree level of deposited layer.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.2
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• pp.193-198
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• 2011

By a nonnegative sign pattern we mean a matrix whose entries are from the set {+, 0}. A nonnegative sign pattern A is said to allow normality if there is a normal matrix B whose entries have signs indicated by A. In this paper we investigated some nonnegative normal pattern that is different to the pattern in [1]. Some interesting constructions of nonnegative integer normal matrices are provided.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.2 no.2
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• pp.1-8
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• 2006

The objective of the present study is to investigate the load delivery characteristics of a hybrid-renewable energy system with geothermal and solar heat sources for hot water, heating and cooling of a residential house in Korea. The hybrid energy system consists of ground source heat pump of 2 RT for cooling with a 150 m vertical U-bend ground heat exchanger, solar collectors of 4.8 m2 and gas fired backup boiler. The averaged coefficient of performance of geothermal module during cooling and heating seasons are evaluated as about 4.5 and 3.8, respectively.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.264-269
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• 2007

본 논문에서는 감각형 객체(Tangible Object)를 이용한 테이블에서의 2D/3D 상호작용 시스템을 제안한다. 제안된 시스템은 기존의 ARTable[1]에 직육면체 형태의 감각형 객체와 카메라가 장착된 이동형 모니터를 추가하여 제작되었다. 감각형 객체는 모든 면에 ARToolkit[3]에서 쓰이는 마커가 부착되어 있으며, 내부에는 진동자와 불루투스 통신 모듈이 삽입되어 있다. 또한 카메라가 달린 모니터는 모니터 암에 연결되어 사용자가 이동하며 ARTable 상판을 관측할 수 있도록 부착되어 있다. 이 시스템를 이용하여 사용자는 디스플레이형 테이블인 ARTable 위에서 가상공간을 네비게이션(2D 상호작용)할 때 정확한 길을 찾아가기 위한 도움을 받을 수 있을 뿐만 아니라, 증강현실 환경에서 가상객체와 3D 상호작용을 할 수 있다. 또한 진동 모듈과 이를 제어하기 위한 블루투스 모듈이 내장 되어있어, 특정한 이벤트 발생시 진동자를 이용하여 사용자에게 촉각 감응 효과를 줄 수 있다. 제안된 시스템은 교육, 엔터테이먼트, 등 다양한 분야에서 사용될 수 있다.