• 전자공학회논문지A
• /
• 제29A권9호
• /
• pp.56-64
• /
• 1992

Because of a small bandgap energy, a high doping density, and a low operating temperature, the dark current in HgCdTe photodiode is almost composed of a tunneling current. The tunneling current is devided into an indirect tunneling current via traps and a band-to-band direct tunneling current. The indirect tunneling current dominates the dark current for a relatively high temperature and a low reverse bias and forward bias. For a low temperature and a high reverse bias the direct tunneling current dominates. In this paper, to verify the tunneling currents in HgCdTe photodiode, the new tunneling-recombination equation via trap is introduced and tunneling-recombination current is calculated. The new tunneling-recombination equation via trap have the same form as SRH (Shockley-Read-Hall) generation-recombination equation and the tunneling effect is included in recombination times in this equation. Chakrabory and Biswas's equation being introduced, band to band direct tunneling current are calculated. By using these equations, HgCdTe (mole fraction, 0.29 and 0.222) photodiodes are analyzed. Then the temperature dependence of the tunneling-recombination current via trap and band to band direct tunneling current are shown and it can be known what is dominant current according to the applied bias at athe special temperature.

• Advances in Computational Design
• /
• 제5권1호
• /
• pp.35-54
• /
• 2020

One of the prevailing structural systems in high-rise buildings is the core-wall system. On the other hand, the existence of one or more underground stories causes the perimeter below-grade walls with the diaphragm of grade level to constitute of a very stiff box. In this case or a similar situation, during the lateral response of a tall building, underground perimeter walls and diaphragms that provide an increased lateral resistance relative to the core wall may introduce a prying action in the core that is called backstay effect. In this case, a rather great force is generated at the diaphragm of the grade-level, acting in a reverse direction to the lateral force on the core-wall system, and thus typically causes a reverse internal shear. In this research, in addition to review of the results of the preceding studies, an improved relationship is proposed for prediction of backstay force. The new proposed relationship takes into account the effect of foundation flexibility and is presented in a non-dimensional form. Furthermore, a specific range of the backstay force to lateral load ratio has been determined. And finally, it is shown that although all suggested formulas are valid in the elastic domain, yet with some changes in the initial considerations, they can be applied to some certain non-linear problems as well.

• Nuclear Engineering and Technology
• /
• 제53권1호
• /
• pp.253-257
• /
• 2021

This work demonstrates the use of baromembrane method based on reverse osmosis (RO) process. The method is realized on mobile complex, which allows to concentrate and determine ultra-low activity of radionuclides in water cooling ponds of Russian nuclear fuel cycle enterprises. The existence level of radionuclide background creates difficult conditions for identification the contribution of liquid discharges enterprise, as standard monitoring methods have a very high detection level for radionuclides. Traditional methods for determining the background radionuclides concentrations require the selection of at least 500 liters (l) of water, followed by their evaporation to form a dry residue. This procedure with RO membranes requires at least 5 days. It is possible to reduce the time and energy spent on evaporation of hundreds of water liters by pre-concentrating radionuclides in a smaller sample volume with baromembrane method. This approach allows preliminary concentration of water samples from 500 l volume till 20 l volume during several hours. This approach is universal for the concentration of dissolved salts of any heavy metals, other organic compounds and allows the preparation of water countable samples in much shorter time compared to the traditional evaporation method.

• International Journal of Computer Science & Network Security
• /
• 제23권5호
• /
• pp.121-127
• /
• 2023

A 500 km/h linear motor high speed terrestrial transportation service is planned to launch 2027 in Japan. In order to support 5G service in the train, the Sub-carrier spacing frequency of 30 kHz is planned to be used instead of common 15 kHz sub-carrier spacing to mitigate Doppler effect in such high-speed transportation. In addition, to increase the cell size of 5G mobile system, plural Base Station antenna will transmit the identical Down Link (DL) signal to form the expanded cell size along the train rail. In this situation, forward and backward antenna signals will be Doppler shifted by reverse direction respectively and the receiver in the train might suffer to estimate accurate Channel Transfer Function (CTF) for its demodulation. In this paper, Delay and Doppler Profiler (DDP) based Channel Estimator is proposed and it is successfully implemented in signal processing simulation system. Then the simulated performances are compared with the conventional Time domain linear interpolated estimator. According to the simulation results, QPSK modulation can be used even under severe channel condition such as 500 km/h, 2 path reverse Doppler Shift condition, although QPSK modulation can be used less than 200 km/h with conventional Channel estimator.

• 접착 및 계면
• /
• 제24권4호
• /
• pp.131-135
• /
• 2023

레시틴은 양친매성 분자로 유기용매상에서 구형의 역 마이셀로 자가조립된다. 이러한 레시틴 용액에 담즙염, 물 등과 같은 첨가제가 들어갈 경우 레시틴의 분자 형태의 구조 변화를 유도하여 역 실린더형 마이셀로의 변환을 이끈다. 이번 연구에서는, 데케인 상에서 레시틴/담즙염 혼합물에 물을 첨가한 후, 유동계를 활용하여 혼합물의 유변학적 변화를 관찰한다. 이렇게 제조된 혼합물들은 점도가 높고 점탄성의 특징을 나타내어 약물전달, 식품젤 등의 다양한 분야에 활용이 가능할 것으로 기대된다.

• 시스템엔지니어링학술지
• /
• 제12권1호
• /
• pp.73-87
• /
• 2016

Combining power generation and water production by desalination is economically advantageous. Most desalination projects use fossil fuels as an energy source, and thus contribute to increased levels of greenhouse gases. Environmental concerns have spurred researchers to find new sources of energy for desalination plants. The coupling of nuclear power production with desalination is one of the best options to achieve growth with lower environmental impact. In this paper, we will per-form a sensitivity study of coupling nuclear power to various combinations of desalination technology: {1} thermal (MSF [Multi-Stage Flashing], MED [Multi-Effect Distillation], and MED-TVC [Multi-Effect Distillation with Thermal Vapour Compression]); {2} membrane RO [Reverse Osmosis]; and {3} hybrid (MSF-RO [Multi-Stage Flashing & Reverse Osmosis] and MED-RO [Multi-Effect Distillation & Reverse Osmosis]). The Korean designed reactor plant, the APR1400 will be modeled as the energy production facility. The economical evaluation will then be executed using the computer program DEEP (Desalination Economic Evaluation Program) as developed by the IAEA. The program has capabilities to model several types of nuclear and fossil power plants, nuclear and fossil heat sources, and thermal distillation and membrane desalination technologies. The output of DEEP includes levelized water and power costs, breakdowns of cost components, energy consumption, and net saleable power for any selected option. In this study, we will examine the APR1400 coupled with a desalination power plant in the Kingdom of Saudi Arabia (KSA) as a prototypical example. The KSA currently has approximately 20% of the installed worldwide capacity for seawater desalination. Utilities such as power and water are constructed and run by the government. Per state practice, economic evaluation for these utilities do not consider or apply interest or carrying cost. Therefore, in this paper the evaluation results will be based on two scenarios. The first one assumes the water utility is under direct government control and in this case the interest and discount rate will be set to zero. The second scenario will assume that the water utility is controlled by a private enterprise and in this case we will consider different values of interest and discount rates (4%, 8%, & 12%).

• 한국통신학회논문지
• /
• 제35권11B호
• /
• pp.1704-1709
• /
• 2010

무기체계 시스템 개발에서는 분명히 기술 선도국이 존재하고 무기체계 개발경쟁에서 앞서 있는 것을 부인할 수 없는데, 여기에 더불어 시스템의 설계 정보에 접근이 거의 불기능하다는 것도 현실이다. 따라서 이미 배치되어 운용되고 있는 선도 시스템과 유사한 무기체계 시스템의 개발이 필요한 경우의 개발 방법론이 필요하다. 한 가지 접근 방법으로 기존에 선진국에서 개발된 유사한 시스템을 분석하여 설계 정보로 참조하고, 이를 기반으로 추가적으로 설계 최적화에 대한 노력을 수행하는 것을 제시할 수 있다. 본 연구에서는 설계정보의 접근에 제약이 있는 선진 시스템에 대해 역공학 분석을 수행하여 설계 정보를 추출하여 정리해서 대상시스템의 기반 설계 정보로 활용하고 이 설계 정보들을 DSM 기법을 활용하여 최적화 설계 구조로 개선하는 방법을 제시하였다. 시스템의 설계 예로 유도무기체계 개발에 적용하였다.

• 한국컴퓨터정보학회논문지
• /
• 제1권1호
• /
• pp.105-128
• /
• 1996

소프트웨어의 전체 비용 중에서 유지보수 비용이 절반 이강을 차지하고 있기 때문에, 이 비용을 줄이기 위한 도구가 필요하다. 유지보수를 위한 공학적인 기법들 중에서 역 공학은 원시 코드로부터 설계 정보를 추출하고 원시 코드를 다른 형태 혹은. 좀 더 추상화된 형태로 표현하는 과정이다. 본 논문에서는 역 공학 기법을 적용하여. 기존 COBOL 프로그램으로부터 프로그램들 간의 호출 관계. 프로그램 내의 논리 구조와 프로그램의 자료 흐름에 대한 정보를 추출하는 방법에 대해서 제안하고 회복된 설계 정보로부터 프로그램 구조조도와 모듈 구조도를 생성하는 방법에 대해서 제시한다. 원시 코드로부터 정확하게 생성된 구조도는 유지보수 자가 프로그램을 전체적으로 혹은, 구체적으로 이해하도록 지원하는 중요한 정의가 될 것이다. 또한. 유지보수 자가 프로그램을 재분석할 때 혹은 다른 유지보수 자들이 그 프로그램을 분석할 때. 명확하게 수정된 구조도는 유지보수 자들에게 프로그램을 더욱 쉽게 이해하도록 지원하게 될 것이다.

• 한국산업정보학회논문지
• /
• 제24권5호
• /
• pp.53-64
• /
• 2019

본 연구에서는 재사용 가능한 제품을 대상으로 순방향물류(Forward logistics)에서 부터 역방향물류(Reverse logistics)에 이르기까지 전체 물류비용과 수요와 회수에 따른 제조업자에서의 재고관리, 재사용을 위한 과정에서 발생하는 청소공정비용 및 폐기비용을 고려한 재사용 네트워크 모델(Reusable network model)을 제안한다. 제안 모델의 유효성을 검증하기 위하여 최적화 기법 중 하나인 유전자 알고리즘(Genetic algorithm: GA)을 이용한다. 파라미터가 해(Solution)에 미치는 영향을 알아보기 위해서 세 가지 파라미터 조건에서 우선 순위형 GA(Priority-based GA: priGA)와, 각 세대(Generation)마다 파라미터가 조정되는 개량형 하이브리드 GA(Modified hybrid genetic algorithm: mhGA)를 사이즈가 다른 4가지 예제에 적용하여 시뮬레이션을 실시한다.

• 한국발생생물학회지:발생과생식
• /
• 제16권3호
• /
• pp.227-233
• /
• 2012

Circadian timing system plays a major role in a wide range of reproductive function. However it is plausible idea that other environmental and/or internal cue might be simultaneously participated in the optimal regulation of reproductive system. In the present study we extended the reverse feeding (RF) time regimen up to 8 weeks, then measured the general and reproductive indices of the animals. The animals of ad libitum feeding group (Control, CON) have free access to food for 4, 6 and 8 weeks, respectively. The day feeding animals (reverse feeding, RF group) have restricted access to food during daytime (09:00-18:00) for 4, 6 and 8 weeks, respectively. When the feeding schedules were over, key indices were measured. After 4 weeks and 8 weeks of feeding, body weights of animals were not significantly different. However, body weights of 6 weeks RF animals were significantly smaller than those of control animals (CON : RF = $333.46{\pm}12.71$ g : $289.91{\pm}8.31$ g, p<0.01). The blood glucose levels of 4 weeks RF animals were significantly decreased compared to the levels of control animals (CON : RF = $161.4{\pm}2.7$ mg/dL : $176.7{\pm}5$ mg/dL, p<0.01) while the levels of 6 weeks RF and 8 weeks RF animals were not different form those of control animals. Reproductive and non-reproductive tissue weights from 6 weeks RF group were significantly lowered than those from CON group (testis, CON : RF = $1.4714{\pm}0.0174$ g : $1.3724{\pm}0.0168$ g, p<0.001; epididymis, CON : RF = $0.3574{\pm}0.0059$ g : $0.3243{\pm}0.0068$ g, p<0.001; seminal vesicle, CON : RF = $0.1655{\pm}0.0068$ g : $0.1328{\pm}0.0054$ g, p<0.001; prostate, CON : RF = $0.3350{\pm}0.0231$ g : $0.2528{\pm}0.0143$ g, p<0.01). After 4 weeks and 8 weeks of reverse feeding, sperm counts in RF animals were markedly reduced than those in control animals[CON 4W : RF 4W = $121.17{\pm}9.96\;({\times}10^6)$ : $50.86{\pm}9\;({\times}10^6)$, p<0.001; CON 8W : RF 8W= $138.69{\pm}9.8\;({\times}10^6)$ : $108.94{\pm}4.22\;({\times}10^6)$, p<0.001]. Present study indicates that RF may induce an adaptable metabolic stress and cause impairment of androgen-dependent reproductive tissues. On-going longitudinal studies will allow a better understanding of the how does mealtime shift affect the reproductive function and exact nature of adaptation.