• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1272-1275
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• 2007

The HDD (hard disk drive) using Load/Unload (L/UL) technology includes the benefits which are increased areal density, reduced power consumption and improved shock resistance than those of contact-start-stop (CSS). Dynamic L/UL has been widely used in portable hard disk drive and will become the key technology for developing the small form factor hard disk drive. Main design objectives of the L/UL mechanisms are no slider-disk contact or no media damage even with contact during L/UL, and a smooth and short load and unload process. In this paper, we focus on state matrix, pitch static attitude (PSA), roll static attitude (RSA), loading/unloading contour (LC/ULC), impact force and contact. Stability of slider is mainly determined by PSA and RSA. State matrix by PSA and RSA is also important indicator. Therefore we analyze state matrix of SFF HDD suspension through the LC/ULC.

• The Plant Pathology Journal
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• 제32권4호
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• pp.363-370
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• 2016

Pseudomonas syringae pv. actinidiae (Psa) causes bacterial canker disease in kiwifruit. Antibacterial activity of plant essential oils (PEOs) originating from 49 plant species were tested against Psa by a vapor diffusion and a liquid culture assays. The five PEOs from Pimenta racemosa, P. dioica, Melaleuca linariifolia, M. cajuputii, and Cinnamomum cassia efficiently inhibited Psa growth by either assays. Among their major components, estragole, eugenol, and methyl eugenol showed significant antibacterial activity by only the liquid culture assay, while cinnamaldehyde exhibited antibacterial activity by both assays. The minimum inhibitory concentrations (MICs) of estragole and cinnamaldehyde by the liquid culture assay were 1,250 and 2,500 ppm, respectively. The MIC of cinnamaldehyde by the vapor diffusion assay was 5,000 ppm. Based on the formation of clear zones or the decrease of optical density caused by these compounds, they might kill the bacterial cells and this feature might be useful for managing the bacterial canker disease in kiwifruit.

• Nuclear Engineering and Technology
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• 제49권4호
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• pp.710-720
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• 2017

In Korea, many nuclear power plants operate at a single site based on geographical characteristics, but the population density near the sites is higher than that in other countries. Thus, multiunit accidents are a more important consideration than in other countries and should be addressed appropriately. Currently, there are many issues related to a multiunit probabilistic safety assessment (PSA). One of them is the quantification of a multiunit PSA model. A traditional PSA uses a Boolean manipulation of the fault tree in terms of the minimal cut set. However, such methods have some limitations when rare event approximations cannot be used effectively or a very small truncation limit should be applied to identify accident sequence combinations for a multiunit site. In particular, it is well known that seismic risk in terms of core damage frequency can be overestimated because there are many events that have a high failure probability. In this study, we propose a quantification method based on a Monte Carlo approach for a multiunit PSA model. This method can consider all possible accident sequence combinations in a multiunit site and calculate a more exact value for events that have a high failure probability. An example model for six identical units at a site was also developed and quantified to confirm the applicability of the proposed method.

• Asian Pacific Journal of Cancer Prevention
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• 제13권11호
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• pp.5529-5533
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• 2012

Aim: To investigate the utility of prostate-specific antigen velocity (PSAV) and PSAV per initial volume (PSAVD) for early detection of prostate cancer (PCa) in Chinese men. Methods: Between January 2009 and June 2012, a total of 193 men (aged 49-84 years, median 67 years) with at least 2 transrectal ultrasonography (TRUS) procedures and concurrent serum PSA measurements underwent prostate biopsy because of suspicion of PCa. The total group were classified into PCa and non-PCa groups, and the variables of the two groups were compared. Univariate and multivariate analyses were used to investigate which variables were predictove. The diagnostic values of PSAV, PSAVD and prostate-specific antigen density (PSAD) were compared using receiver operating characteristic (ROC) analysis. Results: Prostate cancer was diagnosed in 44 (22.8%) of the 193 men. There were significant differences between the groups in last and initial prostate volumes determined by TRUS, initial age, last serum PSA levels, PSAV, PSAD and PSAVD. After adjusting for confounding factors, the odds ratios of PCa across the quartile of PSAVD were 1, 4.06, 10.6, and 18.9 (P for trend <0.001).The area under the ROC curves (AUCs) of PSAD (0.779) and PSAVD (0.776) were similar and both significantly greater than that of PSA (AUC 0.667). PSAVD was a significantly better indicator of PCa than PSAV (AUC 0.736). There was no statistical significant difference between the AUC of PSAV and that of last serum PSA level. The sensitivity and specificity of PSAVD at a cutoff of 0.023ng in participants with last serum PSA levels of 4.0ng/mL-10.0ng was 73.7% and 70.7%, respectively. Conclusions: The results of this study demonstrated PSAVD may be a useful tool in PCa detection, especially in those undergoing previous TRUS examination.

• 한국응용곤충학회지
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• 제26권2호
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• pp.99-106
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• 1987

포장(圃場)에서 월동(越冬)하고 있는 벼 잎집무늬마름병균(病菌) 균핵(菌核)의 밀도(密度)와 그 활성(活性)을 조사(調査)하기 위하여 1986년(年) 12월(月)에 이리(裡里), 나주(羅州), 진주(晋州), 대구(大邱)의 포장(圃場)에서 균핵(菌核)을 채집(採集)하여 발아력(發芽力)과 병원성(病原性)을 조사(調査)하였다. 균핵(菌核)의 밀도(密度)는 이리(裡里), 나주(羅州), 진주(晋州), 대구(大邱) 지역(地域)이 각각(各各) ha당 $2.7{\times}10^6,\;1.2{\times}10^6,\;0.7{\times}10^6,\;0.6{\times}10^6$였으며 지역(地域)에 따라 그중 $42{\sim}78%$(평균(平均) 60%)가 발아력(發芽力)이 있었고 발아(發芽)된 균핵중(菌核中) 평균(平均) 49%가 벼품종(品種) 진흥(振興)에 병원성(病原性)이 있었다. 따라서 발아력(發芽力)과 병원성(病原性)을 동시(同時)에 가진 균핵(菌核)의 비율(比率)은 전체균핵(全體菌核)의 29%였다. 균핵(菌核)으로부터 분리(分離)한 잎집무늬마름병균(病菌)은 배지(培地)에서의 균총형태(菌叢形態)에 따라 3가지 유형(類形)으로 대별(大別)되었으나 유형(類形)이나 균핵(菌核)의 크기, 균핵형성량(菌核形成量)은 진흥(振興)에 대(對)한 병원성(病原性)과 아무런 상관(相關)이 없었다. 10%의 편차(偏差)안에서 평균균핵밀도(平均菌核密度)를 95% 신뢰(信賴)하기 위하여 필요(必要)한 단순임의(單純任意) 표본수(標本數)는 이리(裡里), 나주(羅州), 진주(晋州), 대구(大邱)에서 각각(各各) 41, 132, 232, 395개소(個所)로 산출(算出)되었다.

• 폴리머
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• 제34권6호
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• pp.540-546
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• 2010

본 실험실에서 연구되어진 poly(vinyl alcohol)(PVA)/poly(styrene sulfonic acid-co-maleic acid) (PSSA-MA) 이온교환막에 메탄올 투과도 감소를 위하여 실리카기를 함유하고 또한 프로톤 도너 역할을 할 수 있는 3-(trihydroxysilyl)-1-propanesulfonic acid(THS-PSA)를 도입하여 가교된 PVA/PSSA-MA/THS-PSA 막을 제조하였다. 제조된 막의 내구성 향상을 위하여 500 ppm $F_2$ 기체를 이용하여 시간에 따라 직접불소화를 실시하였으며, 불소기의 도입에 따른 막의 물리화학적 변화를 관찰하기 위하여 접촉각 특정, 열 중량분석 및 X-ray photoelectron spectroscopy(XPS)를 통해 확인하였다. 표면불소화된 PVA/PSSA-MA/THS-PSA막의 전기화학적 특성을 평가하기 위하여 함수율, 이온교환용량, 이온전도도, 메탄올 투과도 측정을 실시하여 상용화된 Nafion 115와 비교하였다. 불소화 시간이 증가함에 따라 도입된 불소의 함량은 최고 4.3%의 함량과 50 nm의 침투 깊이를 나타내었다. 불소화 시간이 60분 경과했을 때 이온전도도는 0.036 S/cm으로 Nafion 115의 0.024보다 향상되었으며, 메탄올 투과도는 $9.26E-08cm^2/s$으로 Nafion의 1.17E-06보다 감소되었음을 확인하였다. 또한 MEA를 제작하여 전류밀도에 따른 셀 전압을 측정하였다.

• Nuclear Engineering and Technology
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• 제50권3호
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• pp.319-326
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• 2018

Since the Fukushima Daiichi nuclear disaster, concern and worry about multiunit accidents have been increasing. Korea has a higher urgency to evaluate its site risk because its number of nuclear power plants (NPPs) and population density are higher than those in other countries. Since the 1980s, technical documents have been published on multiunit probabilistic safety assessment (PSA), but the Fukushima accident accelerated research on multiunit PSA. It is therefore necessary to summarize the present situation and draw implications for further research. This article reviews journal and conference papers on multiunit or site risk evaluation published between 2011 and 2016. The contents of the reviewed literature are classified as research status, initiators, and methodologies representing dependencies, and the insights and conclusions are consolidated. As of 2017, the regulatory authority and nuclear power utility have launched a full-scale project to assess multiunit risk in Korea. This article provides comprehensive reference materials on the necessary enabling technology for subsequent studies of multiunit or site risk assessment.

• 자원리싸이클링
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• 제27권6호
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• pp.44-52
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• 2018

본 연구에서는 동 함유 슬러지로부터 회수된 동 조금속을 황산구리 전해액에서 전해정련 공정 조건을 선택적으로 조절함에 따라 초미세 분말 형태의 동을 회수하고자 하였다. 황산구리 전해액 농도, 인가전류밀도, 첨가제 종류 및 농도에 따라 LSV(Linear Sweep Voltammetry)을 이용하여 초미세 분말 제조가 가능한 인가전류밀도 범위를 설정하여 전해정련 공정을 수행 하였다. 이 때 얻어진 분말에 대해 SEM(Scanning Electron Microscope) 및 PSA(Particle Size Analyzer)를 사용하여 동 분말 형상 및 크기를 분석하였다. 유기첨가제를 사용하지 않은 0.1 ~ 0.4 M 황산구리 전해액 조건에서 동 분말 크기는 인가전류밀도가 한계전류밀도에 가까울수록 감소하였고, 0.2 ~ 0.3 M 황산구리 전해액에서 동 분말 크기가 가장 감소하는 경향을 나타내었다. 또한, 위 실험을 통해 얻은 공정 조건을 바탕으로 유기 첨가제 종류 및 농도를 달리 첨가하여 동 분말 표면 형상 및 크기를 분석하였을 때, Cellulose계 첨가제 2,000 ppm 조건에서 가장 작은 크기(nm급)의 양호한 구형 형태 동 분말을 얻을 수 있었다.

• ETRI Journal
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• 제7권4호
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• pp.11-14
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• 1985

바이폴라 소자로 구성된 회로가 양호한 특성을 갖기 위해서는 개별 소자의 동작 속도, 집적도 및 전력 소비 특성이 좋아야 한다. 그런데 지금까지 주로 사용해온 기존의 SBC 바이폴라 트랜지스터로는 이들 특성을 개선하는 데는 한계가 있었다. 일반적으로 바이폴라 트랜지스터는 면적이 줄어듦에 따라 이들 특성이 개선되므로 본 연구에서는 SBC 방법과는 다른 PSA 공정 방법을 개발하였다. 즉, 소자 격리에서의 종래의 PN 접합에 의한 방법과 다른 산화막에 의한 방법을 도입하였고 또한 에미터, 베이스 사이의 거리를 최소로 줄이기 위하여 다결정 실리콘에 의한 polysilicon self-align 방법으로 에미터 및 베이스를 형성시켰다.

• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1534-1538
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• 2010

Fed-batch cultures of Hansenula polymorpha were studied to develop an efficient biosystem to produce recombinant human serum albumin (HSA). To comply with this purpose, we used a high-purity oxygen-supplying strategy to increase the viable cell density in a bioreactor and enhance the production of target protein. A mutant strain, H. polymorpha GOT7, was utilized in this study as a host strain in both 5-l and 30-l scale fermentors. To supply high-purity oxygen into a bioreactor, nearly 100% high-purity oxygen from a commercial bomb or higher than 93% oxygen available in situ from a pressure swing adsorption (PSA) oxygen generator was employed. Under the optimal fermentation of H. polymorpha with highpurity oxygen, the final cell densities and produced HSA concentrations were 24.6 g/l and 5.1 g/l in the 5-l fermentor, and 24.8 g/l and 4.5 g/l in the 30-l fermentor, respectively. These were about 2-10 times higher than those obtained in air-based fed-batch fermentations. The discrepancies between the 5-l and 30-l fermentors with air supply were presumably due to the higher contribution of surface aeration over submerged aeration in the 5-l fermentor. This study, therefore, proved the positive effect of high-purity oxygen in enhancing viable cell density as well as target recombinant protein production in microbial fermentations.