AISI D2강 위에 다층으로 증착된 WC-Ti_(1-X)Al_(X)N 코팅의 국부부식 거동에 관한 연구

안승호,이정호,김호건,김정구,한전건 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.9

Multilayered WC-Ti_(1-x)Al_(x)N coatings are characterized by periodically repeated structures of lamellae of WC-Ti/WC-Ti_(1-x)Al_(x)N. WC-Ti_(1-x)Al_(x)N coatings of changing Al concentration were deposited on AISI D2 steel by high-ionization sputtered plasma vapor deposition (PVD). The Al concentration could be controlled by using evaporation source for Al and fixing the evaporating rate of other metals. Four kinds of WC-Ti_(1-x)Al_(x)N coatings were prepared: WC-Ti_(0.6)Al_(0.4)N, WC-Ti_(0.53)Al_(0.47)N, WC-Ti_(0.5)Al_(0.5)N and WC-Ti_(0.43)Al_(0.57)N. The corrosion behavior of WC-Ti_(1-x)Al_(x)N coatings was investigated using electrochemical techniques in deaerated 3.5% NaCl electrolyte (galvanic corrosion test, potentiodynamic polarization test, electrochemical impedance spectroscopy and Mott-Schottky method) and surface analyses (GDOES, SEM and EDS). Particular attention was paid to the effect of growth defects on the coating properties related to the corrosion behavior. The results of the coating and substrate galvanic corrosion test showed low galvanic current densities. In the potentiodynamic polarization test and EIS measurement, the corrosion current density of WC-Ti_(0.5)Al_(0.5)N was lower than others and presented higher R_(ct) values than others after 240 h immersion time. This could be attributed to the formation of a Ti oxide, which promotes partial closing of the defects. Capacitance values obtained from EIS as a function of different potentials (C^(-2) vs E) showed that the oxide layer exhibited an n-type semiconductor behavior.

인공고관절용 스테인리스강 316L에 증착된 다이아몬드상 카본 필름의 전기화학적 특성에 관한 연구

김호건,안승호,김정구,박세준,이광렬 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.4

Diamond-like carbon (DLC) films have several advantages in applications such as high hardness, chemical inertness, low friction and electrical insulation. Furthermore, DLC-coated STS 316L films have been reported to have a good biocompatibility, such as the absence of inflammatory response. Thus, corrosion resistance is the first consideration for the biomaterials to be used in the body. DLC films have been deposited onto substrates of STB 316L for artificial hip joints using r.f PACVD (plasma-assisted chemical vapor deposition) with C_(6)H_(6) and mixture of C_(6)H_(6) and SiH_(4) as the process gases. Three kinds of DLC-coated films were prepared as a function of diverse bias voltage and Si incorporation. Corrosion behavior of DLC films was investigated by electrochemical techniques (potentiodynamic polarization test and electrochemical impedance spectroscopy) and surface analyses (atomic force microscopy and scanning electron microscopy). The electrolyte used in his test was a 0.89%NaCl solution of pH 7.4 at temperature 37℃. Electrochemical measurements showed that DLC films with higher bias voltage and Si incorporation could improve corrosion resistance in the simulated body fluid environment. (Received December 5, 2003)

개에서 발생한 악성 정소상피종의 진단 및 치료

시호성, 김일화, 장동우, 안병우, 강현구 충북대학교 동물의학연구소 2008 Journal of Biomedical and Translational Research Vol.9 No.2

본문참고

扶正益氣方의 抗癌活性과 免疫調節作用에 관한 硏究

具滋權,宋昊哲,金東熙,徐榮培,朴陽春,金聖勳 대한본초학회 2000 大韓本草學會誌 Vol.15 No.1

To evaluate the antitum or activity and immune response Bujungikgibang(BJ1GB) studies were done experimentally. The results were obtained as follows: 1. BJIGB extracts exhibited a weak cytotoxicity against SK-OV-3, and SK-MEL-2 cell lines. While it showed cytotoxicity against B16-Fl0 cell line up to 30% of control at concentration of 0.5 mg/ml. 2. BJIGB extracts significantly showed inhibitoty effect on DNA topoisomerase 1 from calf thymus in a dose-dependant manner. 3. BJIGB extracts showed antiadhesive rates against A549, at 30% at 0.5 mg/ml, 60% at 1 mg/ml 4. BJIGB extracts inhibited CAM angiogenesis up to 60%. 5. BJIGB extracts prolonged life span of ICR mice bearing S-180 sarcoma cells up to 130.5%. 6. In FACS analysis, the population of helper T cell was increased weakly, while cytotoxity T cell was decreased insignificantly. 7. The production of nitric oxide in RAW cell stimulated by LPS was incresed at 0.5mg/ml or more in dose dependant fashion as compared with control. 8. Proliferation rate of splenocyte was increased at 0.5mg/ml or more a dose dependant fashion as compared with control. These results suggested that BJIGB extracts might be usefully applied for treatement of cancer and also it was nesessary to do more studies about its mechnisms.

생체모사환경에서 DLC 필름의 부식마모 특성에 미치는 Si 함량의 영향에 관한 연구

김호건,김우중,김정구,박세준,이광렬 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.3

In a method to improve resistance to wear, corrosion and mechanical properties of protective coating, DLC coatings have been extensively studied over the past several years due to their unique combination of properties. Especially, Si-DLC coatings have been attracting increasing interest of researchers since they have a great potential for solving some of the major disadvantages of pure DLC coatings. Si-incorporated diamond-like carbon (Si-DLC) coatings ranging from 0 to 2 at.% were deposited on Ti alloy substrate by means of r.f. plasma-assisted chemical vapor deposition (r.f. PACVD) technique, using mixtures of benzene (C_(6)H_(6)) and silane (SiH_(4)) as the reaction gases. Corrosion and wear behavior of DLC coatings was investigated by electrochemical techniques (potentiodynamic polarization test and electrochemical impedance spectroscopy), tribological techchnique(wear test) and surface analyses (atomic force microscopy, scanning electron microscopy and Raman spectroscopy). It was found that DLC coatings with increasing Si content could acquire improved corrosion and wear resistance in the simulated body fluid environment (0.89 wt.% NaCl of pH 7.4 at 37℃). (Received December 6, 2004)

과학 수행 평가 문항의 선정 및 제작을 위한 평가 준거의 개발

김은진,박현주,강호감,노석구 한국과학교육학회 2003 한국과학교육학회지 Vol.23 No.1

본 연구에서는 과학교육에서 수행평가의 올바른 사용과 정착을 위하여 과학 수행평가문항의 선정과 제작을 위한 평가준거를 개발하였다. 이를 위하여 과학과 평가목표 및 수행평가에 대한 이론적 논의를 통해 평가준거의 대범주로 평가 목표의 충실도(Fidelity), 수행평가의 특징과 구성 요소에 대한 만족도(Satisfaction), 문항의 내용 타당도(Content Validity), 학습자에 대한 내용의 적합도 및 공정성(Suitability & Fairness), 문항의 신뢰도와 객관도(Reliability & Objectivity), 사용상의 편의성 및 실용성(Usability)의 6가지 범주를 개발하였고, 각 대범주별 하위항목을 선정하여, 총 25개의 하위 항목을 가진 평가준거표를 개발하였다. 그리고 개발된 평가준거표의 타당도는 과학교육 연구자 5명의 안면타당도로 보았고, 신뢰도는 3가지 종류의 과학 수행평가문항을 과학교육 전문가 2명과 초등예비교사 6명이 평가하교, 그 결과를 Kendall계수를 통한 평가자간 합치도로 검증하였다. 그 결과 합치도는 통계적으로 유의한 수준으로 나타났다. 이상의 과정을 통하여 최종적인 평가준거표를 완성하여 제시하였다. We have developed of a criterion that would help to select and develop performance assessments in science education. There are six categories of a criterion: Fidelity, satisfaction, content validity, fairness & suitability, reliability & objectivity, and usability. There are the total of 25 sub-categories under the six categories. Five science educators evaluated the validity of the criterion. For reliability of the criterion, Kendall's tau-b was used. Eight science educators and elementary teachers evaluated three performance assessment tasks for the correspondence of the criterion. This study also discuss the implications of this criterions as well.

팔영산 삼림식생과 토양환경

이호준,김종홍,배병호,박문수,전영문,강재구,신정식 建國大學校基礎科學硏究所 1997 理學論集 Vol.22 No.-

전라남도 고흥군 소재 팔영산 (608.6 m) 일대의 삼림군락에 대한 색생조사를 1993년 10월부터 1995년 7월까지 실시하였다. 조사한 자료는 Z-M 방식에 의해 종조성표를 작성하였다. 이에 따라 삼림군락은 신갈나무군락, 졸참나무군락, 굴참나무군락, 서어나무군락, 소나무군락등 5 개 군락으로 분류되었다. 입지와 환경과의 유기적 관계를 조사하기 위해 토양을 분석한 결과, 신갈나무군락은 토양의 비옥도가 높은 산의 능선 부위에 집중 분포하였으며, 굴참나무군락과 소나무군락은 토양의 비옥도가 낮고 비교적 건조한 고도 400 m 이하 지역에 주로 군락을 형성하고 있었다. 또한 졸참나무군락은 고도 300 - 550 m 이내에서 부분적으로 나타났으며, 서어나무군락은 토양의 비옥도가 양호한 고도 300 - 550 m 사이의 골짜기 주변에 국지적으로 분포하였다. 팔영산 삼림식생의 특징은 상록활엽수림이 형성될 수 있는 지역이나 후박나무, 동백나무, 사스레피나무 등의 몇몇 종을 제외하고는 상록활엽수의 분포를 확인할 수 없었으며, 일부 식재림을 제외한 대부분의 지역이 낙엽활엽수와 소나무의 혼효림으로 구성되어 있었다. The phytosociological study forest vegetation on Mt. Palyoung (608.6 m) was investigated from October 1993 to July 1995 in Koheug-Gun, Cheonnam province. According to Z-M method, the floristic composition table of the forest vegetation was divided into five community as follows; Quercus mongolica community, Quercus serrata community, Quercus variabilis community, Pinus densiflora community, Carpinus laxiflora community. The soil was analyzed to investigated the soil conditions and soil fertility. As a result, the organic matters which showing soil fertility were found to be low Quercus variabilis and Pinus densiflora community at comparatively xerophic conditions, below 400 m altitude, while they were increased in Quercus mongolica community on mountain ridge, and that Quercus serrata community was appeared 300-550 m altitude around mountain stream to moderate soilfertility. The forest vegetation of Mt. Palyoung area unconfirmed capable of evergreen broad-leaved forest, but appeared to Machilus thunbergii, Camellia japonica and Eurya japonica species etc. On the other hand, surveyed site's vegetation was distributed mixed forest of deciduous leaved forest and Pinus desiflora, except for some afforestation.

암 생쥐에서 Testosterone으로 인한 유해감각예민도 둔화와 이에 대한 Naloxone의 차단효과

양구범,박제민,김명정,전명호,이국희 대한생물치료정신의학회 2000 생물치료정신의학 Vol.6 No.1

In order to examine the effect of testosterone on antinociception and the role of opioid system as an underlying mechanism, thirty-seven adult female mice(Institute of Cancer Research) were randomized to Naloxone(n=18) and Control group(n=19). Testosterone propionate(1mg/kg, ip) with naloxone HCL(2mg/kg, ip) or with normal saline(5ml/kg, ip) was administered on the first and the third experimental days. Nociceptive sensitivity was measured by Tail flick test(TFL, sec) before and after injection on the first and the third experimental days. The same dose of testosterone was injected on the second experimental day. The results were as follows; 1.TFL of control group was significantly increased by testosterone. TFL of control group measured on the first experimental day before and after injection were 5.5±1.1 sec(mean±sd) and 6.3±1.2 sec, respectively, and the change was significant(t=4.06, p=0.001). That measured on the third experimental day before injection was 5.9±1.0, showing a significant increase compared to that of the first experimental day(t=2.37, p=0.029). 2.Testosterone-induced antinociception was blocked by naloxone. In naloxone group, change in TFLs measured before(5.6±0.8) and after(5.3±0.9) injection was not significant on the first experimental day. On the third day, TFL measured before injection(6.6±1.2) was increased significantly than that of the first experimental day(t=2.87, p=0.011), but it decreased to baseline level after injection of naloxone(5.3±1.3; t=4.73, p=0.000). From these results, it is suggested that testosterone has antinociceptive effect, which is mediated by endogenous opioid system.

면외변위의 정량적 계측을 위한 ESPI와 Shearography의 비교

최정구,김경석,장호섭,정성욱 朝鮮大學校 機械技術硏究所 2005 機械技術硏究 Vol.8 No.2

Electronic Speckle Pattern Interfrometry is a common method for measuring out-of-plane displacement and in-plane displacement and applied for vibration analysis and strain/stress analysis. However, ESPI is sensitive to environmental disturbance, which provide the limitation of industrial application. On the other hand, Shearography based on shearing interferometer can directly measure the first derivative of out-of-plane displacement, which is insensitive to vibration disturbance. This paper proposes the out-of-plane displacement extraction technique from results of Shearography by numerical processing and measurement results of ESPI and Shearoraphy are compared quantitatively.

연봉제 임금체계의 국제비교에 대한 탐색적 접근에 관한 연구

이종구;김호원 경희대학교 산업관계연구소 2006 産硏論叢 Vol.31 No.-

Salary system of the developed countries is based on the annual salary system. There are some slight differences among the systems in the countries, though, those countries have the foundation of long history and the prevalence so as to have settled annual salary system in common. This research is to compare and analyze the structure and characteristics of annual salary systems of the United States, Japan, Germany and the one of Korea. The research has been conducted as the exploratory study on the annual salary system of the US, Japan, Germany with domestic and foreign data. Meanwhile, the empirical analysis has been performed for 71 companies of Korea, which had adopted the annual salary system, to derive the types of the system. In this way, the research could perform the comparison and analysis between the system of the advanced countries and the one of Korea, which is still early on, in terms of the types, the application positions, valuation system, change range of annual pay and the purpose of the system adoption. After this, some suggestions for adopting original annual salary system in Korean companies could be deducted. The result of this research shows that the merit pay system has not accomplished the original goal in the America. As for Japan, the annual salary system had an obstacle of some difficulties to have objective valuation, and the companies maintained seniority-based pay system in general like in Korea. Therefore, Korean companies need to have a care not to adopt American-style merit pay system totally and abolish seniority-based pay system, which has been basis of the salary system, in process of expanding and adopting the annual salary system in Korea. In the beginning, it is considerable to build korean-style annual salary system, which has an influence of employee's performance, with the seniority-based system. The influence of the performance and the ability on the payment can be increased after managing better valuation system.