• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.60-65
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• 2007

Acoustic chamber was developed for verifying the performance of a satellite under the launch condition on the Space environment test department. As the size of a satellite is increased the extension of existing facility is required. This paper encompasses the following items; redesign of components in acoustic chamber, product procedures of them and review of the test for the components of satellite in the upgraded acoustic chamber.

• Journal of the Korean Vacuum Society
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• v.2 no.1
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• pp.50-57
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• 1993

이원계 박막확산쌍에서 열처리 방법에 의한 고상 비정질화 반응의 경향성을 예측하기 위하여 유효 구동력 개념을 제시하였다. 고상 비정질화 반응은 두 원소의 물리적 혼합물과 비정질상간의 최대 자유에너지차로 주어지는 열역학적 구동력(ΔGmax)과 확산원소의 원자반경에 대한 기지의 유효 침입형자리 반경의 비로 주어지는 구조적 요소(Rm/d)가 충족될 때 일어나는 빠른 확산에 의하여 발생된다고 고찰하고, 유효 구동력 기준을 이용하여 금속/금속계 뿐만 아니라 금속/실리콘 계의 고상반응에 의한 비정질상 생성 경향성을 예측하고 실험결과들과 비교하여 잘 적용됨을 보였다. 또한, 유효 구동력 기준이 금속/실리콘 계에서 비정질상의 임계 성장두께 경향성의 예측에도 잘 적용됨을 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.4
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• pp.769-779
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• 2015

In this paper, the ideal standard design and construction of plant factory systems with the Green IT technologies is proposed. For feasibility and problem analysis, a container-type plant factory which was integrated with hardware and software of elemental technologies was operated as a test bed. This operation testing and research will be the foundation of the future construction and operation of large plant factories.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.10a
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• pp.29-30
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• 1995

산업폐수는 종종 희석용액 내에 많은 유독성 물질을 함유하고 있다. 산업폐수를 처리하는 분리공정으로 역삼투막과 한외여과와 같은 막분리 기술은 분리 공정이 간단하고 상변화없이 폐수용량을 크게 감소시킬 수 있고 에너지 소모가 작은 장점을 가지고 있어 그 적용이 확산되고 있다. 계면활성제의 흡착성을 이용한 한외여과 막분리는 높은 막투과속도와 계면활성제의 높은 선택성이 결합된 것인데, Sodium Dodecyl Sulfate(SDS)와 같은 계면활성제를 이용하여 폐수로부터 불용성 중금속 이온과 독성의 유기물질을 분리하는 데에 적용할 수 있다. 임계미셀농도(CMC) 이상에서의 농도에서, 60~200 계면활성제 분자들이 거대분자나 미셀을 형성하면서 서로 응집된다. 그러므로 음으로 하전된 미셀과 결합된 금속 음이온은 2,000에서 10,000 범위의 분자량을 가지는데 역삼투막(RO)보다 작은 압력에서 상당히 큰 막투과속도를 가진 한외여과막에 의해 선택적으로 제거될 수 있다 본 연구의 목적은 중공사 한외여과막의 막투과속도에 미치는 인자들의 영향과, 계면활성제의 흡착성을 이용한 중공사 한외여과 막분리계 성능에 미치는 금속의 형태, S/M 몰비등의 효과를 결정하는데 있다.

• Journal of the Korean Chemical Society
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• v.32 no.4
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• pp.311-317
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• 1988

The solubilities of naphthalene in ammonia could be measured at various temperatures and pressures above the critical point of ammonia to represent the relationship between the solubility and the density of ammonia at desired temperature and pressure by means of a simple equation. This equation allows a calculation of the solubilities at higher and lower pressures. Using the equation, the solution energies, the solution entropies, and the second cross virial coefficients between naphthalene and ammonia have been determined to be compared with those in the case of the dissolution of naphthalene in supercritical carbon dioxide.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.389-394
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• 2007

Recently, a location-based threshold-endorsement(LTE) scheme is proposed to thwart bogus data injection attacks. The scheme exhibits much greater filtering power than earlier symmetric schemes and results in enhanced energy savings. In this paper, we show that LTE has fatal vulnerabilities. We also propose an improved scheme that mitigates the weakness and thereby achieves the original claims without lessening remarkable filtering power intended in LTE.

• Nuclear Engineering and Technology
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• v.7 no.2
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• pp.119-126
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• 1975

On the assumption that the spectral distribution of prompt fission neutrons released from supercritical accidents can be expressed by the generalized Cranberg form with two spectral parameters, which is then transformed into the single parameter form, a variation of the fission spectrum-averaged cross-sections for some threshold reactions with varying the spectral parameter has teen calculated using an electronic computer. It appears that the average cross-sections are very sensitive to the spectral deformation, especially those for the detectors having the threshold at high neutron energy are high compared to those for the detectors of which the threshold energies are comparatively low.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.177-180
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• 2009

This study was investigated to know the thermal decomposition for the propellant ingredients and 2 kinds of HTPE propellants. The thermal analysis of the propellant ingredients used in this study showed that the thermal stability of these materials decreases in the following order : AP > HTPE > AN > BuNENA. In addition, propellant HTPE 002 containing AN showed that an endothermic process at around $125^{\circ}C$ corresponding to the solid-solid phase change($II{\rightarrow}I$) of AN was followed by the exothermic process due to decomposition of BuNENA/AN until $200^{\circ}C$. The critical temperature, $T_c$, of thermal explosion for the propellants HTPE 001 and HTPE 002, were obtained from the non-isothermal curves at various heating rates, by using Semenov's thermal explosion theory. Kissinger's method was employed to obtain the activation energy of the thermal decomposition, and it was used to calculate the $T_c$.

• The Journal of the Korea Contents Association
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• v.8 no.8
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• pp.253-260
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• 2008

The research for a 3-axial accelerometer sensor has increased dramatically in the fields of cellular phone, PDA, etc. In this paper, we develop a human walking detection algorithm using 3-axial accelerometer sensor and a user interface system to show the activity expenditure in real-time. To measure a walking number more correctly in a variety of walking activities including walking, walking in place, running, slow walking, we propose a new walking number detection algorithm using adaptive threshold value. In addition, we calculate the activity expenditure base on counted walking number and display calculated activity expenditure on UI in real-time. From the experimental results, we could obtain that the detection rate of proposal algorithm is higher than that of existing algorithm using a fixed threshold value about $5{\sim}10%$. Especially, it could be found out high detection rate in walking in place.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.75-85
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• 2016

A pyrotechnic system consisting of donor/acceptor pair separated by a gap relies on shock attenuation characteristics of the gap material and shock sensitivity of the donor and acceptor charges. Despite of its common use, numerical study of such pyrotechnic train configuration is seldom reported because proper modeling of the full process requires precise capturing of the shock wave attenuation in the gap prior to triggering a full detonation of high explosive and accurate description of the high strain rate dynamics of the explosively loaded inert confinements. We apply a Eulerian level-set based multimaterial hydrocode with reactive flow models for pentolite donor and heavily aluminized RDX as acceptor charge. The complex shock interaction, critical gap thickness, acoustic impedance, and go/no-go characteristics of the gap test are quantitatively investigated.