• JSTS:Journal of Semiconductor Technology and Science
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• 제1권1호
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• pp.84-93
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• 2001

An electromagnetic micro x-y stage for probe-based data storage (PDS) has been fabricated. The x-y stage consists of a silicon body inside which planar copper coils are embedded, a glass substrate bonded to the silicon body, and eight permanent magnets. The dimensions of flexures and copper coils were determined to yield $100{\;}\mu\textrm{m}$ in x and y directions under 50 mA of supplied current and to have 440 Hz of natural frequency. For the application to PDS devices, electromagnetic stage should have flat top surface for the prevention of its interference with multi-probe array, and have coils with low resistance for low power consumption. In order to satisfy these design criteria, conducting planar copper coils have been electroplated within silicon trenches which have high aspect ratio ($5{\;}\mu\textrm{m}$in width and $30{\;}\mu\textrm{m}$in depth). Silicon flexures with a height of $250{\;}\mu\textrm{m}$ were fabricated by using inductively coupled plasma reactive ion etching (ICP-RIE). The characteristics of a fabricated electromagnetic stage were measured by using laser doppler vibrometer (LDV) and dynamic signal analyzer (DSA). The DC gain was $0.16{\;}\mu\textrm{m}/mA$ and the maximum displacement was $42{\;}\mu\textrm{m}$ at a current of 180 mA. The measured natural frequency of the lowest mode was 325 Hz. Compared with the designed values, the lower natural frequency and DC gain of the fabricated device are due to the reverse-tapered ICP-RIE process and the incomplete assembly of the upper-sided permanent magnets for LDV measurements.

• 한국해양공학회지
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• 제33권6호
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• pp.648-656
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• 2019

The ecological changes in the ocean due to the drastic global warming require that action be taken to sustain the productivity of fisheries. Proper ocean facilities could help prevent the loss of the expenditures made on marine aquaculture and reduce the related compensation for various ocean conditions. The aim of this study was to develop a floating ocean wave-breaker using an eco-friendly concrete and conducting a site survey, a structural analysis, and a test of towing the tank. As a result, the wave at the fish farm would be reduced. The results of the holding power of anchors and the capability of moving the floating structures were considered in the design of the wave-breaker. The analyses of the material properties of concrete and the steel structures, as well as the CAPEX and OPEX analyses of the manufacturing and operation processes confirmed the superiority of the floating concrete wave-breaker. In particular, this study demonstrated that the concrete floating breakwater can protect the fish farm against typhoons and reverse-waves, thereby reducing losses of the fish.

• 대한토목학회논문집
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• 제35권3호
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• pp.663-670
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• 2015

현재 수립된 대부분의 대중교통관련 계획에서는 투자우선순위를 결정함에 있어 중요도(importance) 분석 없이 시설물 조사와 설문 조사를 통해 시설물에 대한 설치율과 만족도(performance)가 낮은 항목을 우선적으로 고려하여 투자순위를 결정하고 있다. 본 연구에서는 구조방정식모형(SEM: Structural Equation Model)을 활용하여 버스 이용자의 통행시간에 대한 중요도와 만족도를 동시에 고려할 수 있는 중요도-만족도 분석(IPA: Importance-Performance Analysis) 기법을 제시하였다. 수도권과 비수도권을 대상으로 버스이용자에 대한 IPA 분석을 실시한 결과 수도권의 경우 우선적인 개선이 필요한 항목으로는 버스정차횟수, 교차로수, 배차간격, 승차대기시간 및 신호체계 순서로 분석되었고, 비수도권의 경우 수도권의 역순인 신호체계, 승차대기시간, 배차간격, 버스전용차로 및 교차로수 순서로 분석되었다.

• Journal of Medicine and Life Science
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• 제17권1호
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• pp.29-32
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• 2020

As respiratory syncytial virus(RSV) is transmitted either via directly contact with an infected case or via indirectly contaminated fomites or skin, the major preventive measures are strict hand hygiene, early detection of transmitted sources, and rapid isolation of RSV patients. Especially early detection of hidden cases is the most critical control measure when an index case was notified in a postpartum center. The Guideline of Korea Centers for Diseases Control and Prevention defines potential contacts in an epidemiologic survey as admitted newborns, parents of index cases, center's workers, and visitors for 10 days before the first diagnosis day of index case. However, it needs to classify potential contacts in more detail in order to conduct a successful survey. Authors conducted to search related literatures and appraise the evidences. Firstly, potential contacts would be classified into RSV-related symptomatic contacts(SxC) and asymptomatic contacts. And then, mother, caring workers, and visitors of the index cases among asymptomatic contacts would be defined as the asymptomatic close contacts(ASCC). Finally, the rest would be defined as the asymptomatic regular contacts(ASRC). The defined test using reverse transcription-PCR is applied to SxC and ASCC, and decision of isolation or regular activities are made according to the results. The rapid antigen detection test kits are applied to ASRC. These suggestions might be helpful to detect hidden cases earlier and prevent a further infection.

• 치위생과학회지
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• 제9권4호
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• pp.461-467
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• 2009

The purpose of this study was to find out the degree of self-consciousness of oral malodor, the status of oral hygiene care, some oral examination factors, and measurement values of malodor compounds through conduction oral examination and questionnaire survey, and measuring volatile malodor compounds by instrumental analysis. The data were collected from 155 patients visiting a dental clinic by using a self-administered questionnaire, conducting oral examination for halitosis, and measuring malodor compounds with Oral Chroma. The rate of recognizing their breath as 'somewhat bad' were 80.0% for the female patients and 74.3% for the male, and, however, 14.3% of the male recognized their breath as 'very bad' while 18.8% of the female did not recognized oral malodor, showing statistically significant difference between gender(p=0.004). The average concentrations of volatile sulfur compounds measured by Oral Chroma were 1.65 ng/10 ml for hydrogen sulfide, 1.71 ng/10 ml for methyl mercaptan and 1.66 ng/10 ml for dimethyl sulfide, on the average, respectively, exceeding malodor threshold levels of all 3 compounds, and were significantly higher in the male group than those in the female, also exceeding all threshold levels except hydrogen sulfide values of the female group. The type of oral malodor was the most prevalent for Type I as 23.2%, followed by Type V, Type IV, Type II whileas Type I and Type IV in the female as 30.6% and 25.9% respectively, showing statistically significant difference by gender(p=0.006). The correlations among oral examination indices was the highest between tongue fur score and simplified oral hygiene index, followed by a significant reverse correlation between the number of fixed prosthodontic teeth and the number of dental caries(p=0.000).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.271-274
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• 2000

Gas sensor materials capable of detecting hydrogen gases (H$_2$) or nitrogen oxides (NO$\_$x/, primarily NO and NO$_2$) with high sensitivity have attracted much interest in conjunction with the growing concern to the protection of global environments. Beside conventional sensor materials, such as semiconductors., conducting polymers and solid electrolytes, the potential of sensor materials with a new method for detecting hydrogen gases or nitrogen oxides gas has also been tested. The breakdown voltage of porous varistors shifted to a low electric field upon exposure to H$_2$ gas, whereas it shifted to a reverse direction in an atmosphere containing oxidizing gases such as O$_3$ and NO$_2$ in the temperature range of 300 to 600$^{\circ}C$. Furthermore, it was found that the magnitude of the breakdown voltage shift, i. e. the magnitude of sensitivity, was well correlated with gas concentration, and that the H$_2$ sensitivity was improved by controlling the composition of the Bi$_2$O$_3$ rich grain boundary phase. However, NO$\_$x/ sensing properties of porous varistors have not been studies in detail. The objective of the present study is to investigate the effect of the composition of the Bi$_2$O$_3$ rich grain boundary phase and other additive such as A1$_2$O$_3$ on the hydrogen gases (H$_2$) sensing properties of porous ZnO based varistors.

• Journal of Welding and Joining
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• 제27권6호
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• pp.31-35
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• 2009

When conducting CTOD test, especially in thick welded steel plate, fatigue pre-cracking occasionally failed to satisfy the requirements of standards thus making the test result invalid. Internally accumulated residual stress of test piece has been thought as one of the main reasons. The propagation of fatigue crack, started from the tip of machined notch, which might have propagated irregularly due to residual stress field. To overcome this kind of difficulty three methods to modify the residual stress are suggested in standard i.e. local compression, reverse bending and stepwise high-R ratio method. In this paper not only multi pass welding but also local pre-compressing process of thick steel plate has been simulated using finite element method for clarifying variation of internal welding residual stress. The simulated results show that welding residual stress is compressive in the middle section of the model and it is predominantly increased after machining the specimen. Comparing as-welded state all component of the welding residual stress changing to compressive in the tip of machine notch whereas residual stress of the outer area remain as tensile condition relatively. Analysis results also show that this irregular residual stress distribution is improved to be more uniformly by applying local compression.

• 한국콘텐츠학회논문지
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• 제21권3호
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• pp.1-9
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• 2021

홀로그램 피라미드는 플로팅 홀로그램의 응용으로, 착용형 장비 없이 다각도에서 3D 홀로그램을 감상할 수 있게 하는 장치이다. 저렴하고 제작이 간단하다는 장점으로 교육, 프로토타이핑, 쇼케이스 등 다양한 분야에서 사용되고 있다. 그 중에서도 데스크톱형 홀로그램은 기존의 홀로그램 피라미드의 크기를 키워 더욱 선명하고 크게 홀로그램을 감상할 수 있게 하였다. 하지만 다각도에서 홀로그램 피라미드를 감상할 수 있음에도 불구하고, 피라미드의 각각의 면이 이어지는 곳에서 홀로그램을 감상할 경우, 홀로그램이 끊기거나 왜곡되는 현상이 있다. 뿐만 아니라, 기존 홀로그램 피라미드에 투사되는 영상은 단순히 각각의 면에 홀로그램을 90도씩 회전시킨 4개의 뷰를 투사하도록 제작되어 있기 때문에, 사용자가 다양한 각도에서 홀로그램을 감상하더라도 4개의 각도에서 바라본 뷰 밖에 보지 못한다. 본 논문에서는 이러한 문제를 해결하기 위해 사용자의 위치를 추적하여 사용자의 시선 각도에 해당하는 홀로그램 영상을 생성 후, 역으로 왜곡하여 투영된 홀로그램이 왜곡되지 않는 방법을 제안하고, 기존의 홀로그램 피라미드 영상을 사용한 결과와 새롭게 제안한 방법을 적용한 결과를 비교 하였다.

• Journal of Veterinary Science
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• 제23권6호
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• pp.92.1-92.8
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• 2022

Background: Feline calicivirus (FCV) is widespread throughout the world. An FCV infection is associated with conjunctivitis, rhinitis, and mouth ulcers that can lead to the animal's death. Because vaccination is not always effective, it is necessary to monitor the infection regularly. Objectives: This study examined the FCV epizootic situation in the Moscow metropolitan area by conducting a molecular phylogenetic analysis of the virus isolates. Methods: Samples from 6213 animals were examined by a reverse transcription polymerase chain reaction. For phylogenetic analysis, 12 nucleotide sequences obtained from animal samples were selected. Sequencing was performed using the Sanger method. Phylogenetic analysis was conducted using the Maximum Likelihood method. Results: The FCV genome was detected in 1,596 (25.7%) samples out of 6,213. In 2018, calicivirus was detected in 18.9% of samples, 27.8% in 2019, 21.4% in 2020, and 32.6% in 2021. Phylogenetic analysis of the F ORF2 region and the ORF3 start region led to division into two FCV genogroups. Most of the isolates (8 out of 12) were close to the Chinese strains. On the other hand, there were isolates closely related to European and American strains. The isolates circulating in Moscow were not included in clusters with vaccine strains; their nucleotide similarity varied from 77% to 83%. Conclusions: This study revealed a high prevalence and genetic diversity of the FCV in Moscow. The epizootic situation remains stably tense because 24 viruses were detected in 25% of animals annually.

• 대한한의학방제학회지
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• 제31권4호
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• pp.283-293
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• 2023

Objectives : Native to East Asia, Japan, and Korea, Cinnamomum japonicum Siebold (CJ) is renowned for its aromatic leaves and bark. We previously assessed the antioxidant activity of fractionated CJ branches (CJB:70% EtOH extract), including hexane (CJB1), chloroform (CJB2), ethyl acetate (CJB3), butanol (CJB4), and water (CJB5). Our findings revealed that CJB3 exhibited the highest antioxidant activity. Here, we aimed to investigate whether CJB3 possesses cytoprotective effects and induces the activity of antioxidant enzymes in hepatocytes. Methods : As HepG2 cells were the first to exhibit the key characteristics of hepatocytes, we investigated the hepatoprotective effects of CJB3 on HepG2 cells. Results : Before conducting the cell experiment, we checked that CJB3, up to a concentration of 100 ㎍/mL, did not exhibit cytotoxicity toward HepG2 cells. ROS production increased because of t-BHP treatment decreased in a concentration-dependent manner upon CJB3 treatment. We confirmed that CJB3 inhibited t-BHP-induced cell death. CJB3 was found to reverse the expression of proteins associated with t-BHP-induced apoptosis. We also observed that CJB3 induced Nrf2 phosphorylation and the nuclear translocation of Nrf2. And, CJB3 treatment caused a time-dependent enhancement of GCL and NQO1 protein expression. We further confirmed that CJB3 increased the expression of Nrf2 target genes, and this effect was associated with the activation of JNK, p38, and AMPK. Conclusion : CJB3 prevents t-BHP-induced oxidative stress and apoptosis and enhances the expression of Nrf2 target genes via JNK, p38, and AMPK activation. These results suggest that CJB3 is a promising candidate for the treatment of liver diseases.