韓國에서의 高等失業問題 硏究를 위한 豫備的 接近

金奎原 慶北大學校 1992 論文集 Vol.52 No.-

This paper addresses a new approach to the study of educated unemployment problem. After reviewing the extant literature on this subject area, it provides a distinction for the related concepts and further suggests that there should be five different aspects of this educated unemployment phenomenon. The author maintains that the conventional explanations begin by assuming a natural balance of power distribution and end up examining a market structure as given. Within this narrow scheme, it is no wonder to regard any failure to get employment opportunites from the labor market as an individual problem. The author also states that radical perspectives in general have a tendency to over-react to conservative standpoints. In going too far in the opposite direction, the former have substituted impersonal non-market forces, such as capitalism or world-system, for the latter's impersonal market forces. Finally, he argues that a balanced version should include serious attention to the ways in which the domestic political-economic powers have responded to changes in the international division of labor. The role of the state within a develop-ing country, in general, and its specific policies in the vortex of class conflicts, in particular, should be examined by a historical-structural analysis, as for fruitful research in the future.

병풀(Centella asiatica) 엑스-베타시클로텍스트린 고체 분산체를 함유한 폴록사머 407 히드로겔 제조 및 피부투과

김경국,곽은선,이계원,박진규,박목순,지웅길 충남대학교 약학대학 의약품개발연구소 1998 藥學論文集 Vol.14 No.-

Extract of Centella asiatica(ECA), which is poorly water-soluble extract from the Centella asiatica is known to express excellent wound healing properties. ECA-β-cyclodextrin (asiaticoside-β-cyclodextrin and genin-β-cyclodextrin) solid dispersion system, which was prepared by freeze-drying method, was formulated as gels containing poloxamer 407 and propylene glycol, and evaluated with respect to their viscosity. stability, skin permeation and drug amount in the skin of hairless mouse. The average molar ratio asiaticoside-β-CD and genin-β-CD was 1:1,7 and 1:22, respectively. When the molar ratio of genin and β-CD was 1:5, madecassic acid made 100% solid dispersion system and asiatic and about 65%. In dissolution study, >99% of asiaticoside from asiaticoside-β-CD was dissolved in 5 minutes, and >99% madecassic acid and >64% asiatic acid from genin-β-CD. The apparent viscosity of poloxamer 407 gels with ECA-β-CD solid dispersion system increased in proportion to poloxamer 407 and gels showed that asiaticoside was most stable and madecassic acid stable and asiatic acid similar to stability of gel with free ECA. The permeation amount of asiaticoside in poloxamer gels through-hairless mouse skin decreased as the concentration of poloxamer 407 increased. When propylene glycol was added at the level of 10%, the permeation amount of asiaticoside at poloxamer gels through hairless mouse skin increased but from 15% it decreased. The permeation of asiaticoside into the skin of hairless mouse was estimated to be about 0.10 ㎍/㎠.

저가 후막 EL소자 제조 및 신뢰성 평가

강계원,김대연,이영훈,강봉석,박정현,최병호 금오공과대학교 산업기술개발연구원 2000 産業技術開發硏究 Vol.16 No.-

AC powder electroluminescence(EL) device consists of seven layers : PET substrate, transparent electrode, phosphor layer, dielectric layer, two layer metal electrodes and protective layer. Etch layer needs to control to improve electrical and optical properties. Both phosphor and dielectric layer among them is more important to increase its properties. For long-time reliability, proper choices of passivation and sealing material are essential. In this paper, influence of phosphor and dielectric layer thickness on EL performance is studied. Type of cellulos is selected as a sealing material to avoid moisture. To add two type of plasticizer to resin improves flexibility and passivation of EL devices. Through this experiments, technologies of fabrication low-cost thick film EL device can be established.

이트라코나졸 경구제제의 제제설계 및 평가

장혜진,김정수,이계원,지웅길 忠南大學校 生命科學硏究院 醫藥品開發硏究所 2006 藥學論文集 Vol.21 No.-

We prepared oral formulations of itraconazole by hot-melt process to increase dissolution rate of this drug. Oral liquid preparations of drug were prepared by melt method with lactic acid and blended with co-solvent, antioxidant and surfactant. Glycofurol and isopropyl alcohol were used as co-solvents, and ascorbic acid and as-corbyl palmitate were used as antioxidants, and TPGS and Gelucire 44/14 were used as surfactants. The final preparations contained 10% of itracnoazole as drug content percentage. The dissolution profiles of itraconazole from liquid preparation were determined at 37±0.5℃ at a stirring rate of 100 rpm using the paddle method. The oral absorption of itraconazole liquid preparation was studied in the rabbits. Major pharmacokinetic parameters (AUC_(0-48hr), C_(max), T_(max)) were calculated from the plasma concentration-time data. The dissolution rate of itraconazole was higher for itraconazole liquid preparation filled into a hard gelatin capsule with 90% release within 20min as compared to 20% for Sporanox capsules. Both the AUC_(0-48hr) and C_(max) values of liquid formulation prepared with isopropyl alcohol were higher than those of itraconazole prepared with glycofurol. The dissolution rate of itraconazole liquid preparation was higher as compared to Sporanox capsules. The bioavailability of drug prepared with isopropanol were higher than those of drug prepared with glycofurol.

흡착 우라늄 이온의 전기 탈착거동

정종헌,원휘준,최왕규,김계남,이성호,오원진 한국공업화학회 2003 응용화학 Vol.7 No.1

Liquid wastes containing uranium ions in high concentration of chemical salts havebeen treated by electrosorption on a activated carbon fibers(ACFs) electrode. Effectiveuranium (VI) removal is accomplished when the potential is -0.5V(vs. Ag/AgCl) ormore negative. For a feed concentration of 100mg/1, the concentration of U(VI) in thecell effluent is reduced to less than 1mg/1, and electrosorption capacity over 500mg/uranium/gACF is reached. The adsorbed uranium can be desorbed up to 99%for 20h by passing a 1.9N NaCl solution at pH 3 through the cell and applying a potential of +1.2V. The amount of desorbed uranium increased as the solution pHwas lowered and the applied potential increased.

염산 메트폴민을 함유하는 경구방출제어형 제제의 제조 및 용출특성

구본철,김정수,이계원,지웅길 忠南大學校 生命科學硏究院 醫藥品開發硏究所 2006 藥學論文集 Vol.21 No.-

Metformin is an antihyperglycemic agent of the biguanide class used in the treatment of non-in-sulin-dependent diabetes mellitus. Metformin hydrochloride has intrinsically poor permeability in the lower portion of the GI-tract leading to absorption almost exclusively in the upper part of the GI-tract. Its oral bioavailability is in the range of 50 to 60%. It also has a very high water solubility. In this study, we prepared sustained release matrix system containing metformin hydrochloride using various characteristics of polyethylene oxide (PEO). The metformin hydrochloride matrix tablets were prepared by direct compressed method and wet granulation compressed method with various molecular weight of PEO. Even though the molecular weights of PEOs used were 900K, 2,000K, and 5,000K. Moreover, three types of matrix tablets were formulated compositions were same, the hardness was different. The release kinetics were studied for 9 hours in pH 1.2 simulated gastric fluid and pH 6.8 simulated intestinal fluid, using a dissolution tester at 37.5℃, 50 rpm. As the molecular weight of PEO increased, the release rate decreased due to the slower swelling and dissolution of PEO. For the effect of hardness of matrix tablets, the rate of drug release was decreased with increasing hardness.

비페닐 디메틸 디카르복실레이트(DDB)의 용출향상을 위한 고체분산체의 제조 및 평가

이정우,김정수,이계원,지웅길 忠南大學校 生命科學硏究院 醫藥品開發硏究所 2006 藥學論文集 Vol.21 No.-

Biphenyl dimethyl dicarboxylate(DDB) is synthetic compound derived from Schizandrin C, a component of Fructus Schizandrae. DDB is currently employed as an agent against virally induced hepatic injury and has been found to be effective in improving liver function and symptoms of patients with chronic viral hepatitis. But, DDB is practically water-insoluble and its dissolution rate is extremely low, resulting in very low bioavailability(20-30%). To improve the dissolution rate of DDB, solid dispersion particles of DDB were prepared with two different types of hydrophilic polymers such as Eudragit E100, hydroxypropylmethylcellulose(HPMC) by spray drying method. Properties of solid dispersions were characterized by DSC and PXRD. DDB tablets were prepared by compressing the powder mixtures composed of raw DDB, solid dispersions, lactose and Avicel PH102, magnesium stearate. At ratio above 1:3(w/w), DDB was amorphous state within DDB-Eudragit E100 solid dispersion. As the weight ratio of Eudragit E100 to DDB was increased, the dissolution rate of DDB-Eudragit E100 solid dispersion tablets was reached 69.37-98.29% after 30min. But, it rapidly decreased to 28.34-45.98% after 2hour due to precipitation of DDB. However, in case of 1:3:1 DDB-Eudragit E100-HPMC solid dispersion tablet containing HPMC, dissolution rate was reached 97.47% after 2hour without decrease of dissolution rate. From overall findings, DDB formulation containing Eudargit E100 and HPMC solid dispersion could be used to remarkably improve the dissolution rate in dosage form of tablets.

五加皮의 效能에 대한 硏究

최민호,이계복,조규원,박진영,김경수,송정석,한종현 한국전통의학연구소 2003 한국전통의학지 Vol.13 No.1

The purpose of this study is to measure the changes of regional cerebral blood flow (rCBF) and blood pressure (BP) of Cortex Acanthopanacis in rats, and to determine the effect of Cortex Acanthopanacis on phenylephrine (PE) induced contraction of isolated rat thoracic aorts. The measurement was continually monitored by laser-doppler flowmeter (Transonic Instrument, USA) and pressure transducer (Grass, USA) in anesthetized adult Sprague-Dawley rats through the data acquisition system composed of MacLab and Macintosh computer. Contractile force was measured with force displacement transducer under 1.5 g loading tension. The result of this experiment was as following; 1. Cortex Acanthopanacis did not effect the changes of rCBF and blood pressure significantly. 2. Contractions evoked by phenylephrine were decreased significantly by Cortex Acanthopanacis 3. L-NNA, ODQ, atropine and indomethacin significantly altered the relaxation of Cortex Acanthopanacis. 4. Propranolol did not change the relaxation of Cortex Acanthopanacis. These results indicate that Cortex Acanthopanacis did not change the rCBF and BP, but Cortex Acanthopanacis can relax PE induced contraction of isolated rat thoracic aorta and that this increasing contraction related to endothelium and various mechanism.

과산화수소의 농도와 적용시간이 상아질의 깊이에 따라 레진 수복물의 미세인장결합강도에 미치는 영향

손정룡,이계영,강유미,오영택,이광원,김태균 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.5

본 연구의 목적은 심부 상아질과 치수실 상아질에 H₂O₂를 각기 다른 적용시간과 농도로 적용하였을 때, 레진수복물과의 미세인장결합강도에 미치는 영향을 평가하는 것이다. 준비된 각각의 치아에 전형적인 근관와동을 형성하고 다음과 같이 무작위로 1개의 대조군과, 4개의 실험군으로 나누었다: 1군, 전처리를 시행하지 않았다; 2군, 20% H₂O₂를 20분, 10분, 5분간 적용하였다; 3군, 10% 를 20분, 10분, 5분간 적용하였다; 4군 5% H₂O₂를 20분, 10분, 5분간 적용하였다; 5군, 2.5% H₂O₂를 20분, 10분, 5분간 적용하였다. 위와 같이 처리한 후 와동 내를 Superbond C&B(Sunmedical, Co., Shiga, Japan)로 충전하였다. 각 치아는 증류수에 24시간 저장한 뒤 심부 상아질과 치수실 상아질로 잘라 미세인장결합강도 시험을 시행하였다. 각 군에서 측정된 미세인장결합강도를 3-way ANOVA와 Tukey post hoc test로 통계 처리하였다(p < 0.05). 실험 결과 모든 군에서 심부 상아질(D1)의 미세인장 결합강도가 치수실 상아질(D2)보다 높게 나타났다. 평균 결합강도는 H₂O₂의 농도와 적용 시간이 증가할수록 감소하였다. 통계분석에서 상아질의 깊이, H₂O₂농도와 적용 시간이라는 세 가지 변수간의 교호작용 효과는 없으나(p > 0.05). 상아질의 깊이와 H₂O₂농도 사이, H₂O₂농도와 적용 시간 사이에서는 교호작용 효과가 있었다(p < 0.05). SEM 관찰에서는 H₂O₂의 농도가 증가할수록 상아세관이 좀 더 개방된 양상을 보였다. The purpose of this study was to examine the effect of hydrogen peroxide at different application time and concentrations on the microtensile bond strength of resin restorations to the deep and the pulp chamber dentin. A conventional endodontic access cavity was prepared in each tooth, and then the teeth were randomly divided into 1 control group and 4 experimental groups as follows: Group 1, non treated; Group 2, with 20% Hydrogen peroxide (H₂O₂); Group 3, with 10% H₂O₂; Group 4, with 5% H₂O₂; Group 5, with 2.5% H₂O₂; the teeth of all groups except group 1 were treated for 20, 10, and 5min. The treated teeth were filled using a Superbond C&B (Sun medical Co., Shiga, Japan). Thereafter, the specimens were stored in distilled water at for 24-hours and then sectioned into the deep and the chamber dentin. The microtensile bond strength values of each group were analyzed by 3-way ANOVA and Tukey post hoc test(p < 0.05). In this study, the microtensile bond strength of the deep dentin (D1) was significantly greater than that of the pulp chamber dentin (D2) in the all groups tested. The average of microtensile bond strength was decreased as the concentration and the application time of H₂O₂ were increased. Analysis showed significant correlation effect not only between the depth of the dentin and the concentration of H₂O₂ but also between the concentration of H₂O₂ and the application time(p < 0.05), while no significant difference existed among these three variables(p > 0.05). The higher H₂O₂ concentration, the more opened dentinal tubules under a scanning electron microscope(SEM) examination.

ZVS를 이용한 풀 브릿지 단일 전력단 고주파 공진 AC-DC 컨버터의 특성해석

남승식,황계호,오경섭,원재선,조규판,김동희 嶺南大學校 工業技術硏究所 2003 工業技術硏究所論文集 Vol.31 No.2

This paper proposes a single-stage high frequency resonant AC-DC converter using zero voltage switching with high input power factor. The proposed high frequency resonant converter ingegrates a half bridge boost rectifier as power factor corrector(PFC) and half resonant converter into a single stage. The input stage of the half bridge boost converter is working in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. Therefore, high power factor is achieved naturally. The results of simulation using the Pspice have demonstrated the feasibility of the proposed AC-DC converter. The proposed converter will be able to be practically used as power supply.