• 반도체디스플레이기술학회지
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• 제10권1호
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• pp.51-55
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• 2011

The surface passivation is one of the important methods that can improve the efficiency of solar cells and can be classified into two methods: wet-chemical passivation and film passivation. In this paper, chemical HF treatment were employed for the passivation of n-type silicon wafers and their effects were studied. To investigate film passivation effects, the silicon nitride films were also deposited by PECVD (plasma-enhanced chemical vapor deposition) on n-type silicon wafers treated with chemical HF. The minority carrier lifetime measurements were used for evaluation of the passivation characteristics in the all experiments steps. We confirmed that the minority carrier lifetime was improved with chemical HF treatment due to passivation effects by H-termination.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2383-2385
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• 2010

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.1055-1058
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• 2011

• BMB Reports
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• 제44권1호
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• pp.1-10
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• 2011

Inter-cellular communication via diffusible small molecules is a defining character not only of multicellular forms of life but also of single-celled organisms. A large number of bacterial genes are regulated by the change of chemical milieu mediated by the local population density of its own species or others. The cell density-dependent "autoinducer" molecules regulate the expression of those genes involved in genetic competence, biofilm formation and persistence, virulence, sporulation, bioluminescence, antibiotic production, and many others. Recent innovations in recombinant DNA technology and micro-/nano-fluidics systems render the genetic circuitry responsible for cell-to-cell communication feasible to and malleable via synthetic biological approaches. Here we review the current understanding of the molecular biology of bacterial intercellular communication and the novel experimental protocols and platforms used to investigate this phenomenon. A particular emphasis is given to the genetic regulatory circuits that provide the standard building blocks which constitute the syntax of the biochemical communication network. Thus, this review gives focus to the engineering principles necessary for rewiring bacterial chemo-communication for various applications, ranging from population-level gene expression control to the study of host-pathogen interactions.

• 한국환경보건학회지
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• 제43권5호
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• pp.382-392
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• 2017

Objectives: The purpose of this study is to obtain basic data on the development of a risk communication model through an investigation of risk perception for radon and identify effective risk communication channels. Methods: A questionnaire was used to evaluate differences in perception level according to respective communication channels. A chi-squared test was used to analyze the difference in pre- and post-risk communication by communication channel. One-way ANOVA was used to analyze the difference in the radon risk perception rate for each communication channel. Results: All of the communication channels resulted in increased radon risk perception, but there was no statistical difference between them in terms of perception (p>0.05). However, based on previous findings that it is effective to use a multi-channel approach, it is considered that communication channels based on duplicate avenues is most appropriate. Conclusions: It is expected that this study will be used as basic data to better understand the formation of public opinion about radon risk and to understand the social reaction to each risk factor.

• 한국산업보건학회지
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• 제22권4호
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• pp.293-300
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• 2012

Objectives: In chemical hazard communication, information receiver's perception is a important factor, but the study on the perception was few. Therefore, this study evaluated the perception of managers and workers group about chemical hazard communication by chemical hazard communication tools that were being used in fields. Methods: 91 managers and 238 workers were surveyed in two companies where use chemicals. All subjects were asked about the comprehensibility and perception for MSDS and GHS Pictograms being used in their workplaces through face-to-face interviews. Results: Most of the respondents knew MSDS, and more than half of the respondents had used MSDS once or more per year. The level of use to find the information on chemicals with MSDS was higher in the managers in comparison with workers. Also, the managers could understand and find the information on MSDS easier(p < 0.05). In the question asking the meaning of GHS Pictograms, the managers responded more correctly, as well(p < 0.05). 86.8% of the managers and 62.6% of the workers were conscious of the possible health hazards of chemicals that they could be exposed at work. However, among the respondents conscious of the health hazards, only less than 70% were well aware of the contents of the health hazards correctly. Conclusions: In chemical hazard communication, it is very important to evaluate whether information receiver have proper and correct knowledge and perception or not and actions based on the evaluations as well as provide correct information.

• 센서학회지
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• 제23권5호
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• pp.299-304
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• 2014

Optimizing the performance of a composite sensor array is necessary when the number of sensors to choose from is large. In this paper, we present a chemical sensors array optimization method using Wilks Lamda algorithm applicable a device to detect low concentration of alcohol from driver's exhale breath for interlocking engine ignition preventing drink-driving. More than 20 chemical sensors fabricated different synthetic stuffs and heater temperatures by collaborators were nominated, 5 sensors were selected for optimal sensors array using the method, and alcohol samples were well discriminated from the interference gases inside the vehicle. It has been confirmed by Principal Component Analysis (PCA).

• 한국인쇄학회지
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• 제20권2호
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• pp.95-106
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• 2002

The effect of various precipitants on the sizes and the shapes was investigated using a scanning electron microscopes when the ${\alpha}$-FeOOH particles was possible in a selection of an appropriate precipitants after due considerations of the shape and the growth of particles.

• 한국통신학회논문지
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• 제29권6A호
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• pp.667-667
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• 2004

위성망과 같이 DBP(Delay Bandwidth Product)가 큰 고속망에서 전송 지구국의 버퍼는 일시적인 막힘 현상에 의한 전송 효율이 저하되는 것을 방지하기 위하여 큐 현상을 충분히 소화하도록 설계되어야 한다. 뿐만 아니라 버퍼의 어떠한 상태 하에서도 막힘 없는 유연한 전송 패킷의 흐름과 수많은 연결 트래픽 간의 공정성을 보장하고 접속 서비스의 특성에 따라서 정의되는 QOS를 충족시키는 기술이 중요하다. 기존의 버퍼알고리즘들은 여러 네트워크 환경의 다양한 변화에 적절히 대응하지 못하여 위성망과 같은 특수한 네트워크에 적합하지 않다. Floyd에 의해 제안된 RED(Random Early Detection) 알고리즘은 기존의 버퍼 알고리즘과 비교하여 뛰어난 버퍼관리 성능을 보여왔다. 하지만 RED 알고리즘 방식은 TCP 패킷의 연결 수나 네트워크의 변화에 적절히 대응하지 못하여 위성망과 같이 다수의 사용자가 동시 다발적으로 발생할 수 있는 환경에서는 적합하지 못하다. 본 논문에서는 입력 비율에 따라 향상된 버퍼 활용도를 가진 TARED(Target Adaptive REB) 알고리즘이 위성망을 포함한 네트워크 환경에서 향상된 성능을 보이고 제안된 TARED 알고리즘을 이용하면 입력 비율에 따른 버퍼의 점유 레벨의 오버플로우나 언더플로우가 없이 전체 시스템의 성능을 향상시킴과 동시에 네트워크의 적응능력과 시스템의 안정화에 우수함을 보일 수 있었다.

• Current Photovoltaic Research
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• 제5권3호
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• pp.75-82
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• 2017

High efficiency thin film solar cells require an absorber layer with high absorption and low defect, a transparent conductive oxide (TCO) film with high transmittance of over 80% and a high conductivity. Furthermore, light can be captured through the glass substrate and sent to the light absorbing layer to improve the efficiency. In this paper, morphology formation on the surface of glass substrate was investigated by using HF, mainly classified as random etching and periodic etching. We discussed about the etch mechanism, etch rate and hard mask materials, and periodic light trapping structure.