• The Plant Pathology Journal
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• 제23권2호
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• pp.70-75
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• 2007

We conducted an inoculation test using nine open-pollinated families of pine trees to evaluate their susceptibility and mortality in different densities of pine wood nematode. Three-year-old nine open-pollinated pine families were inoculated with Bursaphelenchus xylophilus at levels of 3,000, 5,000, and 7,000 nematodes/seedling in greenhouse. There were no distinct patterns in latent period among three densities of B. xylophilus in all families. Most families showed the first disease symptoms of needle discoloration within 12-15 days after inoculation. However, open-pollinated progenies of Pinus densiflora showed the longest latent period because none of one-year-old needles were wilted until 14 days after inoculation with 5,000 and 7,000 nematodes. One-year-old needles were wilted earlier than current needles in all tested families with all densities of B. xylophilus. Current needles were not wilted until 14 days after inoculation in all seedlings. The mortality of all seedlings rapidly increased from 35 days to 49 days after inoculation, and all died within 80 days except two seedlings. A 3,000 nematodes/100 ${\mu}L$ with sterilized distilled water are enough to screen 3-year-old pine seedlings for resistance to B. xylophilus.

• 한국정밀공학회지
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• 제22권3호
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• pp.115-122
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• 2005

As the digital TV markets rapidly growing, many manufacturers introduce large size flat screen TV units. There are two different display types available to large size models which are plasma and TFT-LCD. Since both are constructed with thin large panels that are mostly fragile to even moderate mechanical shock inputs. Some large size panels are severely resonated by the acoustic sound generated TV which deteriorates video quality. Recognizing the potential problems of large displays, accurate measurement of the panels is to be an essential task for the reliable design. Measurement of mechanical properties of a thin large crystallized panel such as TFT-LCD display with traditional material testing equipments is challenging. Since TFT-LCDs are constructed with combination of brittle glass panels, polymer sheets, and liquid crystal, their properties are not only anisotropic but also usually non-linear. Accurate measurement of the properties often requires very expensive facilities. Especially when the size of the test sample is as large as 40-inch or wider, direct measurement cost is prohibitive. Even worse, machining of the large TFT-LCD to make a smaller size specimen that could be fit into a material tester is not possible because of liquid crystal leakage. A new method fer the measurement of elastic modulus of large TFT-LCD panel is presented in this article. The suggested method provides a simple, economic, and user-friendly way fer measuring the elastic modulus of large panels with considerable level of accuracy.

• 전기학회논문지P
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• 제62권2호
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• pp.57-64
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• 2013

Many accidents are being occurred due to many missteps, etc. at the railway platform. Recently in Korea, efforts to prevent casualties fundamentally are being made by installing and operating the PSD(Platform Screen Door) with underground station building as its center to prevent these casualties of passengers. Although this PSD can solve the problem of public casualties at platform fundamentally, it is impossible to install it at whole station buildings since its installation cost is high, and in case of the ground station building of general railway whose operation speed is higher, installation of PSD is impossible due to the characteristics of railway system. This paper proposes the novel safety equipment using Laser radar sensors for the prevention against casualties of passengers at station buildings where the PSDs are not installed like this. The safety equipment using Laser radar sensors is the safety equipment making an approaching train stopped if the falling object is a person by detecting the obstacle at platform through, and it has the merit possible to apply it to station buildings not only in the underground section but also in the ground section since it may detect accurately under ambient environmental elements such as the snow, rain and yellow dust, etc. also. We developed the prototype of the safety equipment to reduce public casualties at platform by using Laser radar sensors and carried out its performance test, and the result is presented in this paper.

• 한국전기전자재료학회논문지
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• 제24권7호
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• pp.589-593
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• 2011

[ $SnO_2$ ]nano powders were prepared by solution reduction method using tin chloride($SnCl_2{\cdot}2H_2O$), hydrazine($N_2H_4$) and NaOH. The $SnO_2$ thick films for gas sensors were fabricated by screen printing method on alumina substrates and annealed at $300^{\circ}C$ in air, respectively. XRD patterns of the $SnO_2$ nano powders showed the tetragonal structure with (110) dominant orientation. The particle size of $SnO_2$ nano powders at the ratio of $SnCl_2:N_2H_4$+NaOH= 1:6 was about 60 nm. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a test box. Sensitivity of $SnO_2$ gas sensor to 5 ppm $CH_4$gas and 5 ppm $CH_3CH_2CH_3$ gas was investigated for various $SnCl_2:N_2H_4$+NaOH proportion. The highest sensitivity to $CH_4$ gas and $CH_3CH_2CH_3$ gas of $SnO_2$ sensors was observed at the $SnCl_2:N_2H_4$+NaOH= 1:8 and $SnCl_2:N_2H_4$+NaOH= 1:6, respectively. Response and recovery times of $SnO_2$ gas sensors prepared by $SnCl_2:N_2H_4$+NaOH= 1:6 was about 40 s and 30 s, respectively.

• 대한방사선기술학회지:방사선기술과학
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• 제15권2호
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• pp.25-30
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• 1992

With transmitted dose through chest which has the problem of wide variations in absorption, simple film/screen combination method makes it diffucult to image lung field, mediastinum and retrocardiac areas. In order to overcome this, it is very common to use the high kilovoltage technique in diminishing the differences between high and low contrast. We have been adopting this method at department of diagnostic radiology, Seoul National University Hospital. To compare the image of it with that of low kilovoltage technique, we did radiographic tests using beans on the skin. We marked off into three anatomical categories such as lungs, mediastinum and near diaphragm, then attached a bean on a marked area at random. In order to compare with high and low, we took a radiography of high($120{\sim}140\;kVp$) and low($70{\sim}90\;kVp$) kilovoltage tehchniques, respectively at the same time. We have done experiments 320 cases. We evaluated the results of test in response to sensitivity(true positive) and specificity(true negative). In evaluating, we gave them points from 1 to 5 according to true or false. With given points by a radiologist having much experiences, we could acquire the percentage of sensitivity and specificity. The percentage made us to get the schematic table of ROC curve of those two methods. Consequently, high kilovoltage technique appeared 18% better than low kilovoltage technique for detecting beans with our apparatus.

• Journal of Advanced Marine Engineering and Technology
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• 제19권3호
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• pp.50-61
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• 1995

In recent years, many ceramic researchers have discoved various methods of joining ceramic to metal. However, most of these joining methods are perfomed under vacuum and pressured circumstances. So, when we join ceramic to metal,the proceedings are very complicated and require a very high cost. The purpose of this study is to develop a new joining method of an alumina ceramic to an aluminum metal in air atmosphere. The joining condition, such as copper metallizing, nickel plating, brazing, etc. was investigated through the shear strength test of the trial joint. The results obtained from the above experimenta are summarized as follows : 1) In the case of the $Al_2O_3$/$Al_2O_3$joint, the shear strength of the joint was affected by the various foctor such as kaolin content, copper metallizing thickness, firing temperature, firing time. 2) The better shear strength of the $Al_2O_3$/Al joint was obtained when Ni plating was conducted under higher current density than existing plating condition. 3) The shear strength of the $Al_2O_3$/Al joint increases with the Ni plating thickness is confined to the range of this paper. 4) The shear strength of the thermal-shocked specimen($Al_2O_3$/Al joint) was far more deteriorated than that of the as-bonded specimen.

• 한국미생물·생명공학회지
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• 제8권4호
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• pp.237-245
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• 1980

건시 저장 중 부패미생물을 분리동정하고, 유독성 곰팡이의 Aflatoxin 생성 여부를 검사한 결과를 요약하면 다음과 같다. 1) 건시 저장 초기에는 곰팡이가, 저장기간이 길어짐에 따라 세균의 침해가 많았다. 2) 분리 동정한 부패 미생물의 균수는 Asp. sp.가 가장 많았고, Escherichia sp., Mucor sp., Alternaria sp., Penicillium sp. 순으로 많았다. 3) 분리 균주 중 Aspergillus flavus Group과 Penicillium citrimum Series도 동정된 균에서와 저장건시에서 분리한 형광물질은 TLC 상에서의 Rf 값으로 보아 Aflatoxin B$_1$, G$_1$유사물질로 추정하였다. 4) 유시시료 또는 분리균주에서 분리된 Aflatoxin 유사물질은 U. V. absorption spectra 측정 결과 Asp. flavus Group에서 Aflatoxin B$_1$, Pen. citrinum Series 에서 Aflatoxin G$_1$으로 확인되었다. 이것은 앞으로 계속 더 구명하여야 하겠다.

• 한국자동차공학회논문집
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• 제21권3호
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• pp.82-87
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• 2013

In this work, the 1L grade integrated metal DOC/DPF filter that can install in engine manifold position was developed to investigate the effect of platinum-coating amount of filter on the improvement of filter activation temperature and reduction of particulate matter (PM). This filter was installed in 2.9L CI engine which meets the EURO-4 emission regulation. Tests for PM reduction efficiency of filter were conducted under ND-13 mode with full-load test condition. It was revealed that the time to reach the activation temperature of metal filter ($280^{\circ}C$) was shorter as the amount of platinum-coating increased. This short activation time can be helpful for the reduction of CO and HC emissions during cold start condition. At the same time, PM reduced as the coating amount increased. The reduction percentage of $DOC_{40}$, $DOC_{20}$, and $DOC_0$ were 96.7% (2.34 mg/kW'h), 95.1% (3.47 mg/kW'h), and 94.5% (3.69 mg/kW'h) compared to previous result (71.4 mg/kW'h), respectively.

• 대한불안의학회지
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• 제13권2호
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• pp.123-131
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• 2017

Objective : The PTSD Checklist (PCL) is a self-report screen for posttraumatic stress disorder (PTSD) that can be scored for both diagnostic assessment and symptom severity measurement. The most recent revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) contains a number of changes to the definition of PTSD, and the aim of this study was to assess the psychometric properties of the Korean version of the PCL for the DSM-5 (PCL-5-K). Methods : The participants were 204 Korean veterans of the Vietnam War who completed the PCL-5-K, the Mini Mental Status Examination (MMSE), PTSD module of Structured Clinical Interview for DSM-5, Research Version (SCID5-RV PTSD module), Korean version of Impact of Event Scale-Revised (IES-R-K) and Combat Exposure Scale (CES-K). Results : The PCL-5-K demonstrated good internal consistency (${\alpha}=0.972$) and test-retest reliability (r=0.96); the suggested cut-off score for PTSD diagnosis was ${\geq}37$ with 0.88 sensitivity and 0.96 specificity. The PCL-5-K scale correlated highly with the IES-R-K and CES-K. Factor analysis identified only one factor. Conclusion : Among elderly Korean veterans of the Vietnam War, the PCL-5-K demonstrated similar psychometric qualities to those of both the original PCL and subsequent versions. It is expected that the PCL-5-K will be a useful PTSD screening tool.

• 한국콘텐츠학회논문지
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• 제7권5호
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• pp.110-117
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• 2007

최근의 유비쿼터스 미디어의 오디오/ 비디오 기술의 발전은 미디어 화면사이즈와 같은 외형적 특성의 다양화를 가져왔고, 이런 새로운 시청환경은 시청자의 매개 커뮤니케이션 경험을 바꿀 수 있게 되었다. 이에 따라 최근 미디어효과 연구 분야에서는 미디어 자체의 외형적 특성에 대한 관심이 증가되고 있다. 이런 관점에서 본 연구는 유비쿼터스 환경의 DMB폰(2.1인치), PMP(4.3인치), PC모니터(19인치)가 지니는 서로 다른 화면사이즈 특성이 시청자의 화면내용에 대한 기억과 감동에 어떤 영향을 미치는지 실험연구를 통해 고찰한 것이다. 검증결과 화면사이즈가 시청자의 기억과 감동에 미치는 효과는 유의미했고, 큰 화면을 지닌 미디어일수록 시청한 콘텐츠에 대한 화면정보에 대한 기억 및 콘텐츠에 대한 감동에 있어서 더 유리하게 작용하는 것으로 나타났다.