LiTaO_3 단결정을 사용한 압전변압기의 개발

황성필,김무준,하강열,강갑중 한국센서학회 2002 센서학회지 Vol.11 No.3

본 연구에서는 온도에 따른 압전특성이 매우 안정적인 LiTaO_3(x-112°y) 단결정을 이용하여 압전변압기를 제작하고 그 특성을 분석하였다. 제작시 LiTaO_3 단결정의 변환효율이 낮은 단점을 보완하기 위해 Lame'-mode를 이용하여 길이와 폭의 비가 2:1인 압전변압기를 제작하고 PSpice를 이용하여 진동 모드 해석, 입력전압에 따른 출력전압특성 및 진동속도특성을 분석하였다. 제작한 압전변압기는 길이방향의 제 2차 고조파 주파수와 폭방향의 기본공진주파수가 결합된 290.83(㎑)에서 입력전압에 대한 최대출력전압이 나타났으며, 약 10배 정도의 승압비를 얻을 수 있었다. The single crystal of LiTaO_3(x-112°y) has very stable thermal characteristics in a piezoelectric transformer. In this paper, a piezoelectric transformer made of the crystal is newly designed and its operating characteristics are analyzed. The length of the transformer is determined as twice as its width for Lame'-mode because the single crystal of LiTaO_3 has low electro-acoustic efficiency. The electric and vibrational characteristics of the transformer is simulated by the PSpice program, and its results are compared to experimental ones. As the results, the ratio of output voltage to input shows large than 10 at 290.83(㎑), which is the frequency coupled the 2nd harmonic for length and the fundamental for width of the Lame'-mode transformer.

대규모 전력계통의 적용을 위한 전력조류계산법

이창근,황갑주 울산대학교 2002 공학연구논문집 Vol.33 No.1

전력조류계산은 전력계통의 상태를 파악하는데 필요한 도구로 전력계통의 운용과 계획의 기반이 되고 있다. 특히 대상 전력계통의 규모가 커지고 구성설비가 복잡해짐에 따라 보다 효과적으로 전력계통을 해석할 수 있는 조류계산법의 연구가 요청되고 있으며, 현재 우리나라 전력회사의 실무에서는 미국 PTI사에서 개발한 PSS/E 패키지를 수입하여 사용하고 있다. 본 연구는 실계통 규모를 해석할 수 있는 전력조류계산법을 개발하는데 있다. 개발된 산법에는 전력방정식을 풀기 위해 가우스-자이델법과 뉴턴-랍슨법 및 고속분할법을 포함하였으며, 스퍼스 프로그래밍 기법과 객체 지향적 프로그래밍 기법도 도입하였다. 개발한 산법의 성능을 평가하기 위해 IEEE 샘플계통과 우리나라 실계통에 적용하였으며, 그 결과를 실무에서 널리 사용하고 PSS/E의 결과와도 비교하였다. Power flow calculation is a important tool for power system analysis, operation and planning. Therefore many methods to analysis power system have been proposed for decades. In Korea power system, the softwares are developed by the oversea and are not suitable for new computer environments. In this paper focused on developing software which can analyze large scaled power system and be suitable for new computer environment. Developed software includes three well-known algorithms, that is, Gauss-Seidel, Newton-Raphson and Fast-Decoupled method. And it also employees a sparse programming technique, bus ordering scheme and object-oriented programming (OOP). The developed software is tested on IEEE -14, -30, -57 and -118 bus sample system and KEPCO's 823 bus system and their results are compared with those of PSS/E developed by PTI.

大學生의 學校 및 社會에 대한 情報追求行爲 : 부산 대학생을 중심으로

姜大基,黃甲鎭 釜山大學校 學生生活硏究所 1982 硏究報 Vol.18 No.1

The study attempted to investigate the relationship between information-seeking behavior about the university life and society in general and background variables including family structure, class size and departmental employment rate. In this study, alienation and self-esteem were treated as intervening variables. For the analysis, 523 questionnaires were collected from undergraduate students at the Busan National University. A path analysis showed that respondent's self-esteem played a significant role in affecting student's information-seeking behavior and alienation. Among the background variables, class size was the only significant variable related to self-esteem. However, alienation which was assumed to be the major variable influencing information-seeking behavior among students did not show a significant effect on information-seeking behavior. It was assumed that one of the reasons for the very low relationship between these two variables was the structural constraints created by the university system such as extreme competition and anxiety for the among lower grade students.

大學生의 不適應에 관한 社會學的 考察

金成國,黃甲鎭 부산대학교 학생생활연구소 1984 硏究報 Vol.20 No.1

Although prior studies analyze student's adjustment to college exclusively in psychological terms, the adjustment process consists of a range of dimensions. This study develops a sociological approach to the adjustment problem. More specifically, the present study identifies three types of maladjustment (related with learning problems, difficulty in campus life, and student activism, respectively). It also specifies major sources of maladjustment such as individual characteristics (including personality, family background, the organization of university, social structural environment). Empirically, correlation and regression analysis (using a simple recursive path model) show several interesting results: ① The pattern of causal relationship differs according to the types of the maladjustment. ② Self-esteem plays a very important role in explaining the maladjustment. Regardless of maladjustment types, its causal effects are consistently shown. ③ Students' evaluation of politic-economic situation is the most important predictor of their attitude about the student movement. ④ Our measure of the maladjustment is moderately correlated with social psychological measures such as alienation scale and symptom check List-90. In conclusion, it is suggested that future student guidance should be specified to correspond to different types of maladjustment.

Methyl Orange에 依한 Disopyramide Phosphate의 分光光度 定量法

申台容,嚴東玉,黃甲洙 又石大學校 1990 論文集 Vol.12 No.-

A singly charged methyl orange anion(M. O) was found to be extracted with Disopyramide phosphate(DP) as a 1:1 complex in dechloroethane. MO-dichloroethane system gave a yellow color for DP, while in the absence of DP, an organic phase showed almost no color. In this way, the spectrophotometric method was in vestigated for the determination of DP by soivent extraction. The results obtained were as follow: 1. The maximum absorption wavelength of the reaction product was 420nm(ε=6.45×10^3.ℓ·moℓ^-1.㎝^-1) 2. Dichloroethane was the best extracting solvent among the several organic solvents and the most suitable pH range was 5.8~6.3 3. Linear relationship was found between absorbance and concentration in the range of 1 x 10^-5M∼10^-4M for DP. 4. This method was suitable for the spectrophotometric determination of DP in mixed pharmaceutical preparation.

釜山大學校 女學生의 家族價値觀의 近代性에 관한 硏究

李成海,黃甲鎭 부산대학교 학생생활연구소 1983 硏究報 Vol.19 No.1

This article tries to investigate the modernity of family-related values of coeds at Pusan National University. A total of 6,298 female collegians were given questionaires on family related values in May of 1983. A total of 1,002 responses were finally analyzed for this article. Some key findings in the study are as follows: (1) More than 80% of respondents turned out to be modern in the values of family, education and ancestor worship, while only about 55% of respondents did so in the values of marriage, horoscope matching and filial piety. (2)The more education the respondent's mother received, the less modern the respondent(the female student) in the values of marriage, family and ancestor worship. And the higher income levels of the resrondent's family was, the less modern the nespondent was in the ualues of marriage.

複合生藥製劑의 止血作用및 摘出子官筋에 미치는 影響(第4) : 壽脾煎 및 歸脾양에 대하여 On Soo-Bi-Jeon and Kwi-Bi-Tang

殷載淳,李東熙,黃甲洙 又石大學校 1990 論文集 Vol.12 No.-

These experiments were conducted to investigate the pharmacological difference between Soo-Bi-Jeon and Kwi-Bi-Tang extract,, clinically used in gynecology, on the hemostasis and the contractile force of the isolated uterine muscle. For this purpose, the effects of the extracts on the bleeding time in mouse tail and prothrombin time in vitro were estimated. Forthermore, its activity on the isolated uterine muscle in rats were investigated. The results obtained were as following; The bleeding time and prothrombin time were significantly shortened compared with the control group in all samples, The uterotonic action produced by Kwi-Bi-Tang(Sample II), Sample III and IV (the same component crude drugs between not blocked by atropine (10^(-7)M) and cyproheptadine (10^(-7)M). but inlhibited by pretreatment of verapamil (10^(-7)M). On the oter hand, Soo-Bi-Jeon(Sample I) extract relaxed the uterine muscle.

능이버섯의 藥理作用에 관한 硏究

殷載淳,이중원,黃甲洙 又石大學校 1990 論文集 Vol.12 No.-

The pharmacological effects of Sarcodon aspratus extract were investigated. The extract promoted contraction of isolated stomach and ileum, and this contraction was blocked by atropine(7×10^-7M) and cyproheptadine (1.5×10^-7M). The maximum effective dose of the extract was 1.5×10^-3g/㎖. The extract promoted the peristaltic movement of small intestine, and this movement was blocked by atropine. The extract accelerated the secretion of histamine in serum and gastric acid. The serum glucose and total cholesterol levels in alloxan-induced mice were significantly decreased by oral administration of the extract for 7 days. The pharmacological effects of the extract on the central nervous system were little.

Ni-Ferrite-Based Thermochemical Cycle for Solar Hydrogen Production

Hwang, Gab-Jin,Park, Chu-Sik,Lee, Sang-Ho,Seo, In-Tae,Kim, Jong-Won 한국공업화학회 2004 Journal of Industrial and Engineering Chemistry Vol.10 No.6

Ni-Ferrite (NiFe₂O₄) was prepared as a basic _metal oxide for a solar hydrogen production cycle consisting of a methane reduction step and a water-splitting step. All steps were performed at relatively low temperatures (below 1073 K). In the CH₄-reduction step, it was confirmed that CH₄ reduction of the prepared Ni-ferrite progressed through two reaction regions with an increase of reaction time. In one, CH₄ reacted with oxygen discharged from Ni-ferrite (region 1); in the other, the methane self-decomposition occurred (region 2). The water splitting step was performed using the reduced Ni-ferrite after the CH₄ reduction step in the two regions. In the water splitting step after the CH₄ reduction step (region 1), CO and CO₂gas were not detected. The maximum H₂ production rate was about 3.3 mL/min g-metal-oxide at 10 min. The H₂ production rate in the water splitting step after the CH₄ reduction step (region 2) was about 3.3 mL/min g-metal-oxide at any reaction time. We confirmed from the XRD patterns that the phase of the prepared Ni-bearing ferrites was changed in each reaction step and that the phase after the water splitting step returned to the phase before the methane reduction step.

HI-H2O 기상 혼합물에서 Silica 막의 안정성

HWANG Gab Jin,PARK Chu Sik,LEE Sang Ho,Choi Ho Sang 한국막학회 2004 멤브레인 Vol.14 No.3

열화학적 IS 공정에서 요오드화수소의 분해에 적용하기 위하여 화학증착법(CVD)으로 제조된 silica 막의 안정성을 HI-H_2O 기상 혼합물에서 평가하였다. Si 원천으로 tetraethoxysilane을 사용하여 서로 다른 CVD 온도로 기공크기가 100 nm인 α-alumina를 처리하였다. CVD온도는 700^℃, 650^℃, 600^℃이었다. 600^℃에서 수행한 단일 성분의 투과 실험에서 측정한 막의 H_2/N_2 선택도는 CVD 온도 700^℃의 M1 막은 43.2, 650^℃의 M2 막은 12.6, 600^℃의 M3 막은 8.7을 나타내었다. HI-H_2O 기상 혼합물에서 안정성 실험은 450^℃에서 수행하였는데, CVD 온도 650^℃에서 처리된 막이 다른 온도에서 처리된 막보다 더 안정성이 더 좋은 결과를 얻었다. The stability of the prepared silica membrane by chemical vapor deposition (CVD) method in the HI-H_2O gaseous mixture was evaluated aiming at the application for hydrogen iodide decomposition in the thermochemical IS process. Porous α-alumina having pore size of 100 nm was modified by the different CVD temperature using tetraethoxysilane as the Si source. The CVD temperature was 700^℃, 650^℃, and 600^℃. The H_2/H_2 selectivities of the modified membranes which were measured by single-component permeation experiment showed 43.2, 12.6, and 8.7 at 600^℃ for the M1 (CVD temperature was 700^℃), M2 (CVD temperature was 650^℃) and M3 membranes (CVD temperature was 600^℃), respectively. Stability experiment in the HI-H_2O gaseous mixture was carried out at 450^℃. The prepared silica membrane at 600^℃ of CVD temperature was more stable than that at the other CVD temperature.