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인쇄회로 기판의 전기검사에서의 미세 탐침과 패드의 동적 거동 현상 관측
송성민(Seongmin Song),차강일(Gangil Cha),김명규(Myungkyu Kim),전승호(Seungho Jeon),유상석(SangSeok Yu) 대한기계학회 2015 大韓機械學會論文集B Vol.39 No.3
인쇄기판의 양산 신뢰성 확인을 위한 전기검사에서는 다수의 미세 탐침들이 기판의 패드와 접점을 유지하며 회로의 전기적 신뢰성을 확인하는 검사이다. 이 때 다수의 탐침들이 모두 정 정렬 될 수 없으므로 탐침의 충돌하는 위치와 각도는 기판에 심각한 결과를 초래할 수 있다. 본 연구에서는 탐침이 패드와 충돌하는 상황에서 발생할 수 있는 탐침의 미끄러짐 현상을 관측하고자 한다. 탐침은 접촉부가 둥근형상과 평평한 형상의 두 종류를 선정하였고, 탐침 돌출 길이, 탐침 직경, 이송 속도 등이 탐침의 미끄러짐에 주는 영향을 관찰하였다. 이를 통해 전기 검사 시 탐침의 경사에 따라 기판의 패드에 작용하는 수평 인가력과 탐침 경사각 사이의 관계를 조사하였으며, 또 전기 검사 후 미끄러진 탐침의 복원시 발생할 수 있는 탐침과 패드 사이의 역학관계에 대해서도 고찰하였다. 경사각은 탐침의 접촉부가 평평하면서 돌출길이가 짧고, 직경이 크며, 검사 속도가 느린 경우에 작다는 것을 확인하였다. In an electrical reliability test of a printed circuit board (PCB), the impact of the micro probing pins on the PCB needs to be checked to ascertain the quality of the circuit. In this study, the impact of the dynamic movement of the probing pin on the pad was observed. As a misaligned pin can exert horizontal force on the pad of the PCB, this study focused on the behavior of a misaligned probing pin. The parameters of observation were the circular and flat edges of the probing pin. The effects of the speed of movement, diameter, and the length of projection of the probing pin were also investigated. The results demonstrated that slippage angle is strongly affected by the shape of the edge of the probing pin, and that projection length is an important factor affecting pin slippage. In contrast, the speed of movement of the probing pin was able to double the slippage angle.
Kang, Seongmin,Cha, Jae Hyung,Hong, Yoon-jung,Lee, Daekyeom,Kim, Ki-Hyun,Jeon, Eui-Chan Elsevier 2018 waste management Vol.71 No.-
<P><B>Abstract</B></P> <P>This study estimates the optimum sampling cycle using a statistical method for biomass fraction. More than ten samples were collected from each of the three municipal solid waste (MSW) facilities between June 2013 and March 2015 and the biomass fraction was analyzed. The analysis data were grouped into monthly, quarterly, semi-annual, and annual intervals and the optimum sampling cycle for the detection of the biomass fraction was estimated. Biomass fraction data did not show a normal distribution. Therefore, the non-parametric Kruskal-Wallis test was applied to compare the average values for each sample group.</P> <P>The Kruskal-Wallis test results showed that the average monthly, quarterly, semi-annual, and annual values for all three MSW incineration facilities were equal. Therefore, the biomass fraction at the MSW incineration facilities should be calculated on a yearly cycle which is the longest period of the temporal cycles tested.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This study estimates the optimum sampling cycle using a statistical method for biomass fraction estimation. </LI> <LI> The analysis data were grouped into monthly, quarterly, semi-annual, and annual intervals and the optimum sampling cycle for the detection of the biomass fraction was estimated. </LI> <LI> MSW incineration facilities should be estimated on a yearly cycle which is the longest period of the temporal cycles tested. </LI> </UL> </P>
Ye Ryung Cha,Seongmin Kim,Jic Hyun Lee,Ie-Sung Shim 한국원예학회 2020 원예과학기술지 Vol.38 No.1
Salicylic acid (SA) is an important signal transduction molecule that helps plants overcome external stress conditions. Drought stress can strongly impact plants during cultivation. In this study, we investigated the effects of pretreating Chinese cabbage seedlings with exogenous SA during drought stress through physiological and biochemical analyses. The study lasted for 39 days, including a period of 23-day during which Chinese cabbage seedlings were pretreated with SA. Plants were pretreated three or six times with SA (10<SUP>-4</SUP>M) or left untreated (control), and subjected to a 12-day drought period. Leaf samples were harvested before (day 0) and on days 3, 6, 9, and 12 of the drought period. Malondialdehyde (MDA) content, photosynthesis rate, chlorophyll fluorescence, total chlorophyll content, and antioxidant enzyme (catalase, ascorbate peroxidase, glutathione reductase) activities were determined during the drought period. Pretreatment with SA led to enhanced drought tolerance in Chinese cabbage seedlings. Pretreating seedlings six times was found to be more efficacious than three times. SA pretreatment reduced MDA synthesis and prevented leaf rolling and leaf scorching. Additionally, SA pretreatment preserved the photosynthetic apparatus and counteracted the reduced activity of antioxidant enzymes. These results demonstrate that pretreatment with exogenous SA protects Chinese cabbage seedlings from oxidative stress and promotes their growth. We thus conclude that pretreatment with exogenous SA can enhance drought tolerance in Chinese cabbage seedlings.
베체트병 환자에서 저용량 스테로이드 사용과 관련하여 발생한 중심성장액맥락망막병증
차성욱 ( Sungwook Cha ),김경진 ( Kyung Jin Kim ),권성민 ( Seongmin Kweon ),이신애 ( Sinae Lee ),민병철 ( Byungchul Min ),김은성 ( Eunsung Kim ),이정욱 ( Jungwook Lee ) 영남대학교 의과대학 2017 Yeungnam University Journal of Medicine Vol.34 No.1
Central serous chorioretinopathy may induce poor eyesight and serous retinal detachment. However, its exact cause has not been well established thus far. It can be associated with systemic high-dose corticosteroid treatment mainly for young and middle-aged men and may spontaneously regress or recur after withdrawal from corticosteroid. After corticosteroid administration for Behcet`s disease, it is necessary to identify any ocular symptoms. Behcet`s disease can lead to the development of ocular complications, such as uveitis, hypopyon, retinal vasculitis, optic neuritis, angiogenesis, secondary cataract, and glaucoma. It is possible to diagnose any of these complications via optical coherence tomography and digital indocyanine green angio-graphy. It is easy to neglect an ocular symptom that may appear after a low-dose corticosteroid treatment as an ocular complication in patients with Behcet`s disease. Thus, we report on a case concerning high-dose corticosteroid treatment with a literature review.
Nosocomial Outbreak of COVID-19 in a Hematologic Ward
Jung Jiwon,Jungmin Lee,Seongmin Jo,Bae Seongman,Ji Yeun Kim,Cha Hye Hee,Lim Young-Ju,Kwak Sun Hee,Hong Min Jee,Kim Eun Ok,Bae Joon-Yong,Kang Changmin,Sung Minki,Park Man-Seong,Kim Sung-Han 대한감염학회 2021 Infection and Chemotherapy Vol.53 No.2
Background: Coronavirus disease 2019 (COVID-19) outbreaks occur in hospitals in many parts of the world. In hospital settings, the possibility of airborne transmission needs to be investigated thoroughly. Materials and Methods: There was a nosocomial outbreak of COVID-19 in a hematologic ward in a tertiary hospital, Seoul, Korea. We found 11 patients and guardians with COVID-19 through vigorous contact tracing and closed-circuit television monitoring. We found one patient who probably had acquired COVID-19 through airborne-transmission. We performed airflow investigation with simulation software, whole-genome sequencing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Results: Of the nine individuals with COVID-19 who had been in the hematologic ward, six stayed in one multi-patient room (Room 36), and other three stayed in different rooms (Room 1, 34, 35). Guardian in room 35 was close contact to cases in room 36, and patient in room 34 used the shared bathroom for teeth brushing 40 minutes after index used. Airflow simulation revealed that air was spread from the bathroom to the adjacent room 1 while patient in room 1 did not used the shared bathroom. Airflow was associated with poor ventilation in shared bathroom due to dysfunctioning air-exhaust, grill on the door of shared bathroom and the unintended negative pressure of adjacent room. Conclusion: Transmission of SARS-CoV-2 in the hematologic ward occurred rapidly in the multi-patient room and shared bathroom settings. In addition, there was a case of possible airborne transmission due to unexpected airflow.