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열전소자를 이용한 COB LED의 열적 특성 분석에 관한 연구
김효준,김태형,김용갑,황근창,Kim, Hyo-Jun,Kim, Tae-Hyung,Kim, Yong-Kab,Hoang, Geun-Chang 한국전자통신학회 2014 한국전자통신학회 논문지 Vol.9 No.12
This paper was designed to analyze thermal properties using thermoelectric element for air-cooling heat dissipation of 13.2W-class COB LED. For comparative analysis with generally used air cooling methods, the heat sink was designed and produced, and this experiment was conducted to measure the temperature distribution using a contact thermometer while the COB LED was operating for 100 minutes. One result was about $75^{\circ}C$ for the general cooling method, and the other was $57^{\circ}C$ while the thermoelectric element was operating with applying the current of 0.8A to the thermoelectric element. This results confirmed that the method of applying thermoelectric element was much better in the dissipation of thermal condense on the COB LED than that of the general air cooling one. The temperature on the contact points of COB LED using thermoelectric element was decreased about 31% compared with the air cooling method from $75^{\circ}C$ to $57^{\circ}C$. 본 논문에서는 13.2W급 COB LED의 공랭식 방열을 위해 열전소자를 이용하여 열적 특성을 분석하였다. 기존 방식과의 방열 성능을 비교 분석하기 위하여 Heat Sink를 설계 및 제작 하였고 실험은 100분간 COB LED를 구동시켜 접촉식 온도계를 통하여 온도 분포를 측정하였다. 접합부의 온도 측정 결과 열전소자를 사용하지 않는 방식에서는 약 $75^{\circ}C$로 나타났고, 열전소자에 0.8A의 전류를 인가하여 구동하였을 때 $57^{\circ}C$로 열 응집현상이 가장 심한 COB LED 접합부분의 열은 기존의 방식보다 약 31% 감소됨을 확인하였다.
QFN 반도체 패키지의 외형 결함 검사를 위한 효과적인 결함 분류 시스템 개발
김효준,이정섭,주효남,김준식,Kim, Hyo-Jun,Lee, Jung-Seob,Joo, Hyo-Nam,Kim, Joon-Seek 한국융합신호처리학회 2009 융합신호처리학회 논문지 (JISPS) Vol.10 No.2
There are many different types of surface defects on semiconductor Integrated Chips (IC's) caused by various factors during manufacturing process, such as cracks, foreign materials, chip-outs, chips, and voids. These defects must be detected and classified by an inspection system for productivity improvement and effective process control. Among defects, in particular, foreign materials and chips are the most difficult ones to classify accurately. A vision system composed of a carefully designed optical system and a processing algorithm is proposed to detect and classify the defects on QFN(Quad Flat No-leads) packages. The processing algorithm uses features derived from the defect's position and brightness value in the Maximum Likelihood classifier and the optical system is designed to effectively extract the features used in the classifier. In experiments we confirm that this method gives more effective result in classifying foreign materials and chips. 반도체 외관결함에는 발생 요인이 각각 다른 crack, foreign material, chip-out, chip, void 등이 있으며, 검사 시스템에서는 결함 유무 및 결함 분류를 수행하여 효과적인 공정관리가 가능하여야 한다. 본 논문에서는 QFN 패키지 결함의 분류를 위한 알고리즘 및 광학시스템을 제안한다. 제안한 방법에서 분류가 어려운 결함 중 하나인 foreign material 과 chip의 효과적인 분류를 위해 제안한 결함의 위치, 밝기의 특징정보(feature)를 사용한 ML(Maximum Likelihood ratio) 분류방법 및 특징정보 획득에 효과적인 광학계를 제안하였다. 실험 결과에서 분류가 어려운 foreign material과 chip에 대한 신뢰성 높은 분류성능을 보였다.
공정 CV 흑연주철의 주물의 직경이 기지조직 , 기계적 성질 및 초음파전도속도에 미치는 영향
김효준,이상익 ( Hyo Joon Kim,Sang Ik Lee ) 한국주조공학회 1989 한국주조공학회지 Vol.9 No.4
N/A The matrix structure and the morphology of CV graphite are affected by the addition of many kinds of elements, which are contained in the CV graphite cast iron, additives, fading time and cooling rate. The effects of cooling rate on the matrix structure, the shape of CV graphite, mechanical properties and propagation of ultrasonic wave in hypoeutectic CV graphite cast iron were studied. When the diameters of the samples are 50㎜, 35㎜ and 20㎜ 1. CV graphite number showed average 13.8% increase and CV graphite length showed 12.3% decrease with decreasing diameter of the samples. 2. The amount of graphite and ferrite showed average 10.6, 4.3% decrease and the amount of pearlite showed average 23.4% increase. 3. Hardness and tensile strength showed average 3.2%, 9.5% increase and impact strength showed average 1.3% decrease. 4. Ultrasonic wave velocity showed average 1.1% increase.
김효준,Lee Jin-Haeng,Lee Ki Baek,Shin Ji-Woong,Kwon Mee-ae,Lee Soojin,Jeong Eui Man,Cho Sung-Yup,Kim In-Gyu 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-
Glutathione S-transferase (GST) from Schistosoma japonicum has been widely used as a tag for affinity purification and pulldown of fusion proteins to detect protein–protein interactions. However, the reliability of this technique is undermined by the formation of GST-fused protein aggregates after incubation with cell lysates. It remains unknown why this aggregation occurs. Here, we demonstrate that the GST tag is a substrate of transglutaminase 2 (TG2), which is a calcium-dependent enzyme that polyaminates or crosslinks substrate proteins. Mutation analysis identified four glutamine residues in the GST tag as polyamination sites. TG2-mediated modification of the GST tag caused aggregate formation but did not affect its glutathione binding affinity. When incubated with cell lysates, GST tag aggregation was dependent on cellular TG2 expression levels. A GST mutant in which four glutamine residues were replaced with asparagine (GST 4QN ) exhibited a glutathione binding affinity similar to that of wild-type GST and could be purified by glutathione affinity chromatography. Moreover, the use of GST 4QN as a tag reduced fused p53 aggregation and enhanced the induction of p21 transcription and apoptosis in cells treated with 5-fluorouracil (5-FU). These results indicated that TG2 interferes with the protein–protein interactions of GST-fused proteins by crosslinking the GST tag; therefore, a GST 4QN tag could improve the reproducibility and reliability of GST pulldown experiments.
아공정 CV 흑연주철의 주물의 직경이 기지조직 , 기계적 성질 및 초음파전도속도에 미치는 영향
김효준,이상익 ( Hyo Joon Kim,Sang Ik Lee ) 한국주조공학회 1989 한국주조공학회지 Vol.9 No.4
N/A The matrix structure and the morphology of CV graphite are affected by the addition of many kinds of elements, which are contained in the CV graphite cast iron, additives, fading time and cooling rate. The effects of cooling rate on the matrix structure, the shape of CV graphite, mechanical properties and propagation of ultrasonic wave in hypoeutectic CV graphite cast iron were studied. When the diameters of the samples are 50㎜, 35㎜ and 20㎜ 1. CV graphite number showed average 17.9% increase and CV graphite length showed 10.3% decrease with decreasing diameter of the samples. 2. The amount of graphite and ferrite showed average 11.2, 4.1% decrease and the amount of pearlite showed average 15.7% increase. 3. Hardness and tensile strength showed average 3.5%, 11.3% increase and impact strength showed average 1.5% decrease. 4. Ultrasonic wave velocity showed average 1.1% increase.
연교(連翹)가 강제수영부하시험에서 CRF, c-Fos와 TH에 미치는 영향
김효준,이태희,Kim, Hyo-Joon,Lee, Tae-Hee 대한한의학방제학회 2010 大韓韓醫學方劑學會誌 Vol.18 No.1
Objectives : In order to investigate the antidepressant effects of Forsythiae Fructus(FF), we performed the Forced Swimming Test(FST). Also the expressions of corticotropin-releasing factor (CRF), c-Fos and tyrosine hydroxylase(TH) were measured by immunohistochemical method at paraventricular nucleus(PVN), ventral tegmental area(VTA) and locus coeruleus(LC). Methods : Spraque-Dawley rats were administered FF extract(100 mg/kg, 400 mg/kg) intragastrically three times prior to the FST. Results : The duration of immobility in the FST was significantly decreased in the FF 100 mg/kg, 400 mg/kg groups(p<0.05). The expression of CRF was significantly reduced in the FF 100 mg/kg and 400 mg/kg groups(p<0.001). c-Fos expression was significantly decreased at PVN in the FF 100 mg/kg group(p=0.069). TH expression at VTA was significantly increased in the FF 100 mg/kg and 400 mg/kg groups(p<0.05). TH expression at LC was not significantly changed(p=0.346). Conclusion : According to the results, it can be suggested that Forsythiae Fructus has antidepressant effect via the decreased immobility through the reduction of CRF and c-Fos expression at PVN.
Incremental Technique과 Composite Resin을 이용한 손상된 전치부 수복: Case Reports
김효준,Kim, Hyo-Jun 대한심미치과학회 2000 Journal of the Korean Academy of Esthetic Dentistr Vol.9 No.1
Direct bonded restoration with composite resin is one of the few areas which the achievement and result are available in chair side. Especially free-hand bonding technique and incremental technique give us challengeable opportunity for restoring severely damaged anterior teeth. If clinicians have keen sense of observation to evaluate polychromatic characteristics of natural teeth, hue, chroma, value, translucency, opacity and correlate the observation result with various kinds of composite resins, they will have privilege to share joy from restoring damaged anterior teeth in chair side immediately.