Influence of Magnesium Powder and Heat Treatment on the Superconducting Properties of $MgB_2/Fe$ Wires

김남규,김이정,전병혁,김찬중,Tan, Tan Kai,Kim, N.K.,Kim, Y.I.,Jun, B.H.,Kim, C.J. 한국초전도학회 2007 Progress in superconductivity Vol.9 No.1

The most common technique to fabricate $MgB_2$ superconducting wire is by powder-in-tube (PIT) technique. Therefore, the starting powder for the processing of $MgB_2$ superconductors is an important factor influencing the superconducting properties and performance of the conductors. In this study, the influence of magnesium precursor powders and annealing temperatures on the transition temperatures ($T_c$) and critical current densities ($J_c$) of $MgB_2/Fe$ wires was investigated. All the $MgB_2/Fe$ wires were fabricated by in situ PIT process. It was found that higher $J_c$ was obtained for $MgB_2$ wires with smaller particle size of magnesium precursor powders. The $J_c$ also increases with decreasing annealing temperatures.

도핑 비율에 따른 하이브리드 백색 OLED의 효율 향상에 관한 연구

김남규,신훈규,권영수,Kim, Nam-Kyu,Shin, Hoon-Kyu,Kwon, Young-Soo 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.9

We synthesized new materials of $Zn(HPB)_2$ and Ir-complexes as blue or red emitting material. We fabricated white Organic Light Emitting Diodes (OLED) by using $Zn(HPB)_2$ for the blue emitting layer, Ir-complexes for the red emitting layer and $Alq_3$ for the green emitting layer. We fabricated white OLED by using double emitting layers of $Zn(HPB)_2$:Ir-complexes and $Alq_3$. The doping rate of Ir-complexes was varied, such as 0.2%, 0.4%, 0.6%, and 0.8%, respectively. When the doping rate of $Zn(HPB)_2$:Ir-complexes was 0.6%, white emission was achieved. The Commission Internationale de l'Eclairage (CIE) coordinates of the white emission was (0.322, 0.312).

Hole Blocking Layer 사용에 따른 하이브리드 백색 OLED의 색순도 향상에 관한 연구

김남규,신훈규,권영수,Kim, Nam-Kyu,Shin, Hoon-Kyu,Kwon, Young-Soo 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.12

Novel materials of $Zn(HPB)_2$ and Ir-complexes were respectively synthesized as blue or red emitting material. White Organic Light Emitting Diodes (OLED) were fabricated by using $Zn(HPB)_2$ for a blue emitting layer, Ir-complexes for a red emitting layer and $Alq_3$ for a green emitting layer. White OLED was fabricated by using double emitting layers of $Zn(HPB)_2$ and $Alq_3:Ir$-complexes, and hole blocking layer of BCP. We also varied the thickness of BCP. When the thickness of BCP layer was 5 nm, white emission was achieved. We obtained a maximum luminance of $3,500cd/m^2$. The CIE coordinates was (0.375, 0.331). From this study, we could propose that the hybrid structure is efficient in lighting application of white OLED by improvement of color purity.

SCEM's impact on environmental activities SMEs

김남규,황금주,Kim, Namkyu,Hwang, Kumju Korean Resource Economics Association 2008 자원·환경경제연구 Vol.17 No.1

최근 경제와 산업 전반에서 중소기업의 환경성과와 환경활동은 지속가능 발전의 관점에서 특히 관심이 고조되고 있다. 중소기업을 지속가능성 체계(stainability framework)에 포함시키기 위해 진행되고 있는 다양한 노력 중에서도 그 동안 대기업이 주도하던 친환경공급망관리(Supply Chain Environmental Management)는 중소기업의 환경활동을 촉진시키는 유용한 수단으로 인식되고 있다. 본 연구는 우리나라 전기전자산업에서 대기업 주도의 친환경공급망접근방법(SCEM approach)이 중소기업의 환경성과에 미치는 영향에 대하여 실증분석하였다. 연구방법론으로는 설문조사 결과에 대하여 인자분석과 회귀분석을 실시하였다. 계량분석 결과, 대기업 주도의 SCEM이 중소기업의 환경활동촉진에 긍정적인 영향을 미치고 있으며, 특히 친환경공급망접근방법 중에 시장거래(arm's length) 기법보다는 협력적(collaborative) 기법이 더 효과적으로 중소기업의 환경활동 촉진에 기여하고 있다는 점을 제시하였다. 본 연구에서는 다국적 기업의 친환경공급망접근방법 역시 중소기업의 환경활동촉진에 중요한 요인이 되고 있다는 점도 도출하였다. Small and medium sized enterprises' (SMEs) environmental performance and activities have been often of great concern toward sustainability as they have been playing a critically important role in the economic and industrial development. Among many initiatives to engage SMEs into the sustainability framework, Supply Chain Environmental Management (SCEM) of large companies has a great potential to persuade SMEs to adopt environmentally improved activities. This study investigated the relationship between SCEM approaches of large companies and environmental activities of SMEs in the Korean electronics industry. A postal questionnaire survey was used as a data collection method, and factor analysis and regression analysis were applied to analyse the collected data. The empirical findings suggested that SCEM approaches of large companies have positive impacts on environmental activities of SMEs. Among SCEM approaches, the collaborative approach was more effective than the arm's-length approach. Additionally, this study found positive impacts of trans-national SCEM approaches on SMEs' environmental activities.

목탄이 첨가된 $MgB_2$의 초전도 성질에 미치는 열처리 온도의 영향

김남규,탄카이신,전병혁,박해웅,주진호,김찬중,Kim, Nam-Kyu,Tana, Kai Sin,Jun, Byung-Hyuk,Park, Hai-Woong,Joo, Jin-Ho,Kim, Chan-Joong 한국초전도학회 2007 Progress in superconductivity Vol.9 No.1

Charcoal was used as a carbon source for improving the critical current density of $MgB_2$ and the effect of annealing temperature on the $J_c$ of $MgB_2$ was investigated. The charcoal powder used in this study was $1{\sim}2$ microns in size and was prepared by wet attrition milling. $MgB_2$ bulk samples with a nominal composition of $Mg(B_{0.95}C_{0.05})_2$ were prepared by in situ process of Mg and B powders. The powder mixture was uniaxially compacted into pellets and heat treated at temperatures of $650^{\circ}C\;-\;1000^{\circ}C$ for 30 minutes in flowing Ar gas. It was found that superconducting transition temperature of $Mg(B_{0.95}C_{0.05})_2$ decreased by charcoal additions which indicates the carbon substitution for boron site. $J_c$ of $Mg(B_{0.95}C_{0.05})_2$ was lower than that of the undoped $MgB_2$ at the magnetic fields smaller than 4 Tesla, while it was higher than that of the undoped sample especially at the magnetic field higher than 4 T. High temperature annealing seems to be effective in increasing $J_c$ due to the enhanced carbon diffusion into boron sites.

경관 급식의 적용과 투여방법의 실제

김남규,Kim, Nam-Gyu 대한병원협회 1990 대한병원협회지 Vol.19 No.6

도인(挑仁)이 일측 신절제와 streptozotocin으로 유발된 당뇨병성 신증 Rat에 미치는 영향

김남규,오재선,전상윤,Kim, Nam-Kyu,Oh, Jae-Seon,Jeon, Sang-Yun 대한한방내과학회 2014 大韓韓方內科學會誌 Vol.35 No.4

Objectives: Diabetic nephropathy is the most common cause of end stage renal disease. Transforming growth factor (TGF)-${\beta}1$, type IV collagen, advanced glycation end-products (AGEs), and angiotensin II type 1 receptor (AT1) are the main factors of diabetic nephropathy. We investigated the effects of Prunus on renal function and histopathological changes of diabetic nephropathy rat model induced by unilateral nephrectomy and streptozotocin. Methods: Diabetes was induced in male Sprague-Dawley rats ($290{\pm}10g$) by injecting streptozotocin (55 mg/kg) into the tail vein after unilateral nephrectomy. Rats were divided into 3 groups (n=6): normal, control, and Prunus. After 8 weeks of oral administration of Prunus extract on the Prunus group from 3 days after streptozotocin injection, we checked weight, 24 hrs urine, blood biochemistry and renal tissue to evaluate renal function and histopathological changes by examining parameters including albuminuria, BUN, creatinine, cholesterol, low density lipoprotein (LDL), triglyceride, TGF-${\beta}1$, type IV collagen, AGEs, and AT1. We also measured mRNA expression of TGF-${\beta}1$, type IV collagen, AGEs, and AT1 by Real Time polymerase chain reaction (RT-PCR). Results: Prunus decreased the amount of 24 hrs proteinuria, and inhibited histopathological changes of diabetic nephropathy including the expression and accumulation of TGF-${\beta}1$, type IV collagen and AGEs which could promote development of diabetic nephropathy. Prunus also inhibited mRNA expression of TGF-${\beta}1$, type IV collagen. Conclusions: These findings suggest that Prunus might protect the renal function and inhibit the development of renal injury by regulating factors including TGF-${\beta}1$, type IV collagen, AGEs, except AT1, so Prunus can be used for diabetic patients to prevent the progression of diabetic nephropathy.

Update and Debate Issues in Surgical Treatment of Middle and Low Rectal Cancer

김남규,Min Sung Kim,Sami F. AL-Asari 대한대장항문학회 2012 Annals of Coloproctolgy Vol.28 No.5

Based on a review of the literature, this paper provides an update on surgical treatment of middle and low rectal cancer and discusses issues of debate surrounding that treatment. The main goal of the surgical treatment of rectal cancer is radical resection of the tumor and surrounding lymphatic tissue. Local excision of early rectal cancer can be another treatment option, in which the patient can avoid possible complications related to radical surgery. Neoadjuvant chemoradiation therapy (CRT) has been recommended for patients with cT3-4N0 or any T N+ rectal cancer because CRT shows better local control and less toxicity than adjuvant CRT. However, recent clinical trials showed promising results for local excision after neoadjuvant CRT in selected patients with low rectal cancer. In addition, the “wait and see” concept is another modality that has been reported for the management of tumors that show complete clinical remission after neoadjuvant CRT. Although radical surgery for middle and low rectal cancer is the cornerstone therapy, an ultralow anterior resection with or without intersphincteric resection (ISR) has become an alternative standard surgical method for selected patients. Many studies have reported on the oncological safety of the ISR, but few of them have addressed the issue the functional outcome. Furthermore, an abdominoperineal resection (APR) has problems with high rates of tumor perforations and positive circumferential resection margins, and those factors have contributed to its having a high rate of local recurrence and a poor survival rate for rectal cancer compared with sphincter-saving procedures. Recently, great efforts have been made to reduce these problems, and the total levator excision or the extended APR concept has emerged. Surgical management for low rectal cancer should aim to radically excise the tumor and to preserve as much of the sphincter function as possible by using a multimodality approach. However, further prospective clinical trials are needed for tailored treatment of rectal cancer patients.

VRML을 이용한 3차원 전자 카탈로그 저작도구 설계 및 구현

김남규(Nam-Gyu Kim),김대흠(Tae-Hum Kim),김영찬(Young-Chan Kim) 한국정보과학회 2001 한국정보과학회 학술발표논문집 Vol.28 No.1A

인터넷 상거래의 폭발적 증가로 인터넷에서의 전자 카탈로그에 대한 관심이 증폭되고 있다. 그러나 현존하는 사이트는 주로 2차원 서비스만을 제공한다. 따라서 사용자에게 직관적이고 현실에 가까운 정보를 제공하기 위한 3차원 서비스가 요구된다. 이러한 3차원 멀티미디어 컨텐츠 표현 언어로는 VRML이 대표적이나 기존의 VRML 저작도구는 전자 상거래에서 사용되는 전자 카탈로그를 제작하는 기능을 지원하지 않는다. 본 논문에서 구현한 VRML을 이용한 3차원 전자 카탈로그 저작도구는 상품을 나타내는 VRML과 데이터 베이스를 연동하여 사용자에게 직관적이고 현실적인 상품 이미지와 상세한 상품 정보를 제공한다.

4차 산업혁명 시대에 5G의 필요성 및 5G 이동통신 표준화 동향

김남규(Namkyu Kim),김예진(Yejin Kim),허정우(Jeongwoo Huh),최준영(Junyoung Choi),최종윤(Jongyoon Choi),김연석(Yeonseok Kim),나웅수(Woongsoo Na),박래혁(Laihyuk Park),조성래(Sungrae Cho) 한국통신학회 2017 한국통신학회 학술대회논문집 Vol.2017 No.6