• Bulletin of the Korean Chemical Society
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• 제9권2호
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• pp.84-87
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• 1988

The Photophysical and photochemical properties of Ruthenium bipyridine with two long hydrocarbon chains, $[Ru(bipy)_2(dhbipy)]^{2+}$ and transient phenothiazine derivative cation radical $(PTD^+)$ in the cationic vesicle were studied. Transient absorption spectra of cation radical of phenothiazine derivative in the vesicle system containing the $Ru^{2+}$ complex, $[Ru(bipy)_2(dhbipy)]^{2+}$, (1) as sensitizer and phenothiazine derivative as electron donor was observed by XeCl excimer laser photolysis system. Thus the excited ruthenium complex would be quenched by phenothiazine derivative(PTD) reductively in the vesicle system. The quenching rate constant($K_Q$) of $Ru^{2+}$ with two long hydrocarbon chains in the vesicle by PTD was $9.6{\times}10^8M^{-1}S^{-1}$. The absorption decay kinetics showed that lifetime of phenothiazine derivative cation radical is a value in the 4-8m sec range.

• 한국전자파학회논문지
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• 제11권7호
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• pp.1186-1193
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• 2000

본 논문에서는 나카가미 패이딩 채널에서 FH/MFSK 시스템에 선택 다이버시티를 적용하였을 경우의 시스템 성능을 분석한다. 선택 합성(selection combining)후의 신호대 잡음비(SNR)로부터 제거확률을 유도하고 FH/MFSK 시스템의 성분분석을 위해 사용자수(M), SNR, 나카가미 페이딩(m), 다이버시티 가지의 수(D)와 같은 파라메더들을 사용한다. m이 1인 경우, 비트에러율(BER)은 각각 D=1에서 1.0$\times$10-3이고 D=2에서 1.0$\times$10-4으로 10배만큼 감소함을 알 수 있다. m이 2인 경우, BER은 D가 증가하더라도 일정한 값을 갖는다는 것을 또한 알 수 있다. D가 2인 경우, SNR이 15dB와 25dB일 때의 시스템 용량은 다이버시티를 고려하지 않은 용량보다 각각 75%와 20% 증가된다.

• 한국컴퓨터정보학회논문지
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• 제19권10호
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• pp.35-42
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• 2014

주어진 실내 환경에 위치한 여러 장애물에 대한 정보를 사전에 훈련하고 인식하여 로봇의 인지 능력을 향상시키기 위해 스테레오비전 센서의 RGB-D 이미지에서 인텐시티를 기반으로 일정 거리 안에 있는 장애물을 검출하는 기법을 제시한다. RGB-D 인텐시티 정보에 대해 PCA, ICA, LDA, SVM의 주요 패턴인식 알고리즘을 적용하여 인식률 및 실행시간을 구하고, 여러 패턴인식 알고리즘 중에서 어떤 알고리즘이 인식률 및 실행시간 측면에서 적용이 가능한지를 제시한다. 실험결과, RGB-D 데이터와 인텐시티 데이터를 비교한 결과 정확도면에서는 RGB-D 데이터가 4.2% 높은 인식률을 보였으나 훈련시간은 인텐시티 데이터가 RGB-D 이미지에 비해 LDA의 경우 29%, SVM의 경우 31% 빠르게 처리되었으며 테스트시간은 LDA의 경우 70%, SVM의 경우 33% 빠르게 처리되어 모바일 로봇 장애물 인식에 인텐시티 데이터를 사용하는 것이 정확도면에서도 우수하고 처리 속도 면에서 높은 개선효과가 있다.

• Journal of Advanced Marine Engineering and Technology
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• 제8권1호
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• pp.17-36
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• 1984

Since 1973, the competition on the development of fuel saving type internal combustion engines has become severe by the two times oil shock, and new type engines are reported every several months. Whenever these new type engines are developed, new designs are required and they will be offered in the market after performing the endurance test for a long time. But the engine market is faced with a heavy burden of finance, as the developing of a new engine requires tremendous expenses. For this reason, the computer simulation method has been lately developed to cope with it. The computer simulation method can be available to perform the reasonable research works by the theoretical analysis before carrying out practical experiments. With these processes, the developing expenses are cut down and the period of development is curtailed. The object of this study is the development of simulation computer program for the small naturally aspirated four-stroke diesel engine which is intended to product by the original design of our country. The process of simulation is firstly investigated for the ideal engine cycle, and secondly for the real engine cycle. In the ideal engine cycle, each step of the cycle is simulated by the energy balance according to the first law of thermodynamics, and then the engine performance is calculated. In the real cycle imulation program, the injection rate, the preparation rate and the combustion rate of fuel and the heat transfer through the wall of combustion chamber are considered. In this case, the injection rate is supposed as constant through the crank angle interval of injection and the combustion rate is calculated by the Whitehouse-Way equation and the heat transfer is calculated by the Annand's equation. The simulated values are compared with measured values of the YANMAR NS90(C) engine and Mitsubishi 4D30 engine, and the following conclusions are drawn. 1. The heat loss by the exhaust gas is well agree with each other in the lower load, but the measured value is greater than the calculated value in the higher load. The maximum error rate is about 15% in the full load. 2. The calculated quantity of heat transfer to the cooling water is greater than the measured value. The maximum error rate is about 11.8%. 3. The mean effective pressure, the fuel consumption, the power and the torque are well agree with each other. The maximum error is occurred in the fuel consumption, and its error rate is about 7%. From the above remarks, it may be concluded that the prediction of the engine performance is possibly by using the developed program, although the program needs to reform by adding the simulation of intake and exhaust process and assumping more reliable mechanical efficiency, volumetric efficiency, preparation rate and combustion rate.

• 한국식품과학회지
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• 제18권3호
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• pp.226-233
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• 1986

근원섬유단백질의 열안정성에 대한 pH의 영향에 있어서 소의 근육의 경우에 fiber type에 따라 차이를 보이지 않으나, 닭의 근육의 경우에는 fiber type에 따라 안정 pH 범위에 차이를 나타내었다. 한편, 이온강도 및 유기용매의 농도변화에 따른 영향에 있어서는 이온강도가 증가함에 따라 그리고 유기용매의 농도가 증가함에 따라 변성속도가 증가하였으며, 또한 actomyosin의 열안정성이 myosin과 HMM의 열안정성보다 높은 것으로 나타났다. 열안정성에 대한 열역학량$(D\;value,Z\;value,\;{\Delta}H^{\ddag},\;{\Delta}S{\ddag},\;{\Delta}G^{\ddag})$은 red muscle과 white muscle 사이에 명백한 차이를 보였으며 white muscle이 red muscle보다 높은 열안정성을 나타내었으며, 동물의 종류에 따라서도 현저한 차이를 보였다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.317-328
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• 2017

This paper presents design and specific absorption rate analysis of a 2.4 GHz wearable patch antenna on a conventional and electromagnetic bandgap (EBG) ground planes, under normal and bent conditions. Wearable materials are used in the design of the antenna and EBG surfaces. A woven fabric (Zelt) is used as a conductive material and a 3 mm thicker Wash Cotton is used as a substrate. The dielectric constant and tangent loss of the substrate are 1.51 and 0.02 respectively. The volume of the proposed antenna is $113{\times}96.4{\times}3mm^3$. The metamaterial surface is used as a high impedance surface which shields the body from the hazards of electromagnetic radiations to reduce the Specific Absorption Rate (SAR). For on-body analysis a three layer model (containing skin, fats and muscles) of human arm is used. Antenna employing the EBG ground plane gives safe value of SAR (i.e. 1.77W/kg<2W/kg), when worn on human arm. This value is obtained using the safe limit of 2 W/kg, averaged over 10g of tissue, specified by the International Commission of Non Ionization Radiation Protection (ICNIRP). The SAR is reduced by 83.82 % as compare to the conventional antenna (8.16 W/kg>2W/kg). The efficiency of the EBG based antenna is improved from 52 to 74 %, relative to the conventional counterpart. The proposed antenna can be used in wearable electronics and smart clothing.

• Radiation Oncology Journal
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• 제7권2호
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• pp.171-183
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• 1989

Roesch의 생존 방정식속에 세포증식으로 일어나는 생존증가를 가장 일반적 형식으로 포함시킨 식을 유도하고 이 식으로부터 저선량률 방사선에만 적용되는 동결과선량식 (Isoeffect formula)을 유도하였다. 이 저선량률식이 파라메터 하나로 결정해주는 총선량은 Paterson과 Green에 의하여 얻어진 실험 임상결과와 일치한다. 이 파라메터와 선량률 효과 사이의 관계의 의의를 논하였다. 또한 고선량률 분절(fractionation) 치료와 동저선량률 계속치료를 연락하는 동결과 선량식을 유도 사용하여, Ellis가 잰 실험결과와 비교하였다. 그 결과, Ellis와 Paterson이 쓴 'tolerance'의 표준이 $\alpha/\beta$의 비 4Gy에 해당하는 것임이 밝혀졌다. 그러므로 이들의 'tolerance'의 표준은 'early effect'에만 두고 본 것이 아님을 알 수 있다. 개념적인 면에서도, 아래와 같은 새로운 견해가 나올 수 있다. KHT sarcoma의 생존선도 (survival curve)에 선량률 효과가 보이지 않는 이유로 $\alpha/\beta$의 비가 큰 점을 들을 수 있다. 이것은 이 survival curve에 어께 (shoulder)가 보이지 않는 것으로도 증명이 된다. Pierquin이 선량률에 무관하게 head and neck tumor치료에 같은 총선량을 쓴 것을 정당화시킬 수 있다.

• 소성∙가공
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• 제8권3호
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• pp.295-295
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• 1999

In the present study, the corrosion behavior of AZ91D as-cast alloy was investigated form the viewpoint of the distribution aspect of precipitate ($Mg_{17}Al_{12}$) and the variation of Al concentration in the Mg-rich matrix. The dendrite arm spacing (DAS) of an as-cast specimen was measured as a function of degree which describes the distribution aspect of the precipitate, and the salt spray test was conducted for various grain-sired specimens fur 20 days. The dendrite arm spacing increased as the grain size increased to about 150㎛, but a constant value is indicated when the grain size exceeds that range. Although the relationship between the corrosion rate and grain size is of a nonlinear type, the linear trend between the corrosion rate and the dendrite arm spacing is maintained for the overall range of dendrite arm spacing. Since the precipitate in the as-cast alloy is discontinuously distributed, this linear relationship means that the variation of Al-solute concentration in the Mg-rich matrix has a more potent effect than the protective action of the precipitate on the corrosion behavior of an as-cast alloy.

• 한국해양공학회지
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• 제6권2호
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• pp.76-84
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• 1992

In this study, corrosion fatigue test of SAPH45 steel was performed by the use of plane behavior of base metal (BM) and heat affected zone (HAZ) of SAPH45. The main results obtained are as follows: 1) The more aspect ratio (b/t) of corner crack decreases, the more aspect ratio (b/a) takes greatly effect by corrosion. 2) The correlation between the stress intensity factor range ($\Delta$k) and crack growth rate (da/dN) for weldment in seawater is given by Paris rule as follow: da/dN=C($\Delta$K) super(m). Where m is constant, and the value is 3.82-3.84. 3) The accelerative factor ($\alpha$) of BM and HAZ under seawater is about 1.1-1.9, and ($\alpha$) of HAZ increases more and more under the low $\Delta$K region. 4) HAZ is more susceptible to corrowion than BM because of potential of electrode (E sub(c)) of HAZ becomes more less noble potential than that of BM.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4304-4308
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• 2011

Kinetic studies of the reactions of O,O-dimethyl Z-S-aryl phosphorothioates with X-benzylamines have been carried out in dimethyl sulfoxide at $85.0^{\circ}C$. The Hammett (log $k_2$ vs ${\sigma}_X$) and Br$\ddot{o}$nsted [log $k_2$ vs $pK_a$(X)] plots for substituent X variations in the nucleophiles are discrete with a break region between 4-Me and H, while the Hammett plots (log $k_2$ vs ${\sigma}_Z$) for substituent Z variations in the leaving groups are linear. The sign of the cross-interaction constant (${\rho}_{XZ}$) is positive for both the strongly and weakly basic nucleophiles. Greater magnitude of ${\rho}_{XZ}$ (= 2.54) value is observed with the weakly basic nucleophiles compared to with the strongly basic nucleophiles (${\rho}_{XZ}$ = 0.17). The deuterium kinetic isotope effects ($k_H/k_D$) involving deuterated benzylamines [$XC_6H_4CH_2ND_2$] are primary normal ($k_H/k_D$ > 1). The proposed mechanism is a stepwise with a rate-limiting leaving group expulsion from the intermediate involving a frontside nucleophilic attack with a hydrogen bonded, four-center-type transition state for both the strongly and weakly basic nucleophiles.