苦蔘이 家免의 血管收縮抑制에 미치는 影響

권오율,남창규,정찬길 世明대학교 한의학연구소 1999 韓醫學硏究所 論文集 Vol.2 No.-

The purpose of this study was to analyze the effect and mechanism of Sophorae Radix on arterial experimental section contracted by PE(phenyl-ephrine). The results were summarized as follows; 1.Sophorae Radix significantly ingibited the PE-induced contraction of artery, accordingly as concentration of Sophorae Radix increased. 2.Sophorae Radix significantly ingibited the PE-induced contraction of artery both with intact endothelium and removed endothelium. 3.The ingibiting effect of Sophorae Radix on contracted strips was not changed by the pretreatment of NLA(Nω-nitro-L-arginine). 4.Sophorae Radix more significantly inhibited the PE-induced contraction of artery than KCI-induced. 5.The mechanism of inhibition of Sophorae Radix on contracted strips is suggested that Ca++ was blocked from the external medium.

刺人參이 PE로 유발된 토끼의 수축혈관에 미치는 영향

권오율,남창규 世明대학교 한의학연구소 2002 韓醫學硏究所 論文集 Vol.4 No.-

This study was undertaken to define the effect of Oplopanacis Cortex on the phenylephrine-induced arterial contraction and the mechanism of Oplopanacis Cortex-induced relaxation. In order to investigate the effect of Oplopanacis Cortex on contracted rabbit carotid arterial strips, transverse strips with intact or damaged endothelium were used for the experiment using organ bath. To analyze the mechanism of Oplopanacis Cortex-induced relaxation, Oplopanacis Cortex extract infused into contracted arterial strips induced by phenylephrine after treatment of indomethacin, tetraethylammonium chloride or N_(t) nitro-_L-arginine. The relaxation of Oplopanacis Cortex was dependent on the presence of endothelium, showing that Oplopanacis Cortex-indeced relaxation was not observed in the strips damaged endothelium. The endothelium-dependent relaxation induced by Oplopanacis Cortex was suppressed by the pretreatment of N_(t) nitro-_L-arginine, but it was not observed in the strips pretreated or tetraethylammonium chloride. These result demonstrated that Oplopanacis Cortex may inhibit phenylephrine-induced constraction through the production of nitric oxide in the vascular endothelial cells.

계면활성제를 첨가한 TMA-포접화합물의 상변화에 관한 실험적 연구

김창오,정낙규,김진흥,오율권 朝鮮大學校 機械技術硏究所 2001 機械技術硏究 Vol.4 No.1

The purpose of this study is to investigate the propriety of TMA clathrate as a cold storage medium. Particularly, this is to examine the extent of subcooling improvement when the surfactants are added to the TMA clathrate, because water used cold storage material has low phase change temperature and subcooling. This study has been analyzed and compared with TMA 30wt% clathrate how phase change temperature, subcooling and specific heat in the various concentrations are changed. This results view to be improved phase change temperature and subcooling of TMA30wt% as a cold storage medium, when it had some surfactant. Additionally, it is that surfactant must be controlled under available solution limit and study for new additive must be lasted to know its effect.

Foreign Direct Investment in Korea: A Foreign Perspective

Oh Yul Kwon 한국경제연구원 2004 한국경제연구원 연구보고서 Vol.2004 No.-

In contrast to international trade, which expanded rapidly and played the role of engine for economic development in Korea, inward foreign direct investment(FDI) has remained sluggish and failed to contribute significantly to Korean economic growth. Although it is well established that FDI can enrich a host country’s economy in a number of ways, the Korean government restricted and controlled FDI, partic- ularly up to the 1997 financial crisis. As a result, Korea was regarded as the worst place to invest among Asian nations. These restrictions of FDI and unhealthy FDI environments were reflected in the flagging level of FDI in Korea. After 1997, however, the Korean government has under- taken a paradigm shift in FDI policy from “restriction and control” to “promotion and assistance”, and undertaken a series of policy measures and all-out efforts to improve the business environment and attract FDI. As a result, inward FDI in Korea surged over the three-year period 1998-2000. Despite this spurt, the magnitude of FDI in Korea is still small in comparison to other countries, and has been declining sharply since 2001. How then, would the relatively low magnitude of FDI in Korea and a recent sharp decline be explained? What addi- tional measures should Korea undertake to increase FDI inflows to a level comparable internationally? To address these vexing questions from a foreign perspective, a compre- hensive survey was conducted from May to July 2002 of foreign companies that had undertaken FDI and have been operating in Korea. A questionnaire comprising 96 questions was distributed to about 400 foreign companies, and a total of 69 responses were received. According to the survey results, foreign firms undertake FDI in Korea to capitalise on the emerging business opportunities in Korea, and do not consider Korea as a stepping stone to gain market access to other Asian countries. Foreign business people generally have a negative view on the improvements in the Korean business environment in the recent past. Consistent with this, foreign business people point to various types of difficulties in establishing and operating FDI projects in Korea. These difficulties arise not only from excessive, complex and opaque government regulations, the excessive discretionary power of bureaucrats and cronyism and corruption, but also from inept labour relations and high wages, unfair advantages held by domestic firms, inefficient corporate governance of Korean companies, cultural and communication difficulties, Koreans’ prejudice against foreign products, closed Korean society, and poor social amenities for expatriate families. The respondents also consider themselves disadvantaged in a system where Korean firms rely heavily on personal rela- tionships for business operations. They recognise, however, strengths of Korean workers, such as diligence, loyalty toward companies, collaborative team spirit, and willingness to be trained, but point out poor English skills as the weakest aspect ...

Neutral Taxation of Foreign Investment Income with Special Reference to Korea

Kwon, Oh Yul 한국경제학회 1985 The Korean Economic Review Vol.1 No.1

Changes in Matrix Metalloproteinase and Tissue Inhibitors of Metalloproteinase in Patients with Rotator Cuff Tears

Oh-Soo Kwon,Young-Yul Kim,Ji Yoon Ha,Han Bit Kang 대한견주관절의학회 2014 대한견주관절학회지 Vol.17 No.2

Background: The purpose of this study was to determine whether in patients with rotator cuff tears a correlation exists between molecular changes and clinical parameters such as age, duration of symptom, range of motion, and tear size. Molecular changes of matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) were assessed by measuring messenger RNA (mRNA) levels of the two proteins. Methods: The rotator cuff tissue from was obtained from the edge of a torn tendon revealed after debridement by a motorized shaver. Using the sample of rotator cuff tissue, the reverse transcription polymerase chain reaction was performed to quantify MMP-2 and TIMP-2 mRNA expression. To determine whether mRNA levels and the clinical variables, such as age, defect size, range of motion (ROM) of shoulder, and duration of symptoms, show any correlation, Spearman’s correlation coefficients were used to test for significant differences. Results: There was an inverse correlation between the mRNA levels of MMP-2 and TIMP-2 from the torn rotator cuff tendons regardless of the clinical variables. However, comparison of mRNA levels versus clinical parameters such as age, defect size, range of motion and duration of symptoms revealed a number of findings. We found a significant correlation between age and mRNA levels of MMP-2 from torn cuffs (r = 0.513, p = 0.021). Further, we found a significant correlation between defect size in the full thickness tears and mRNA levels of MMP-2 (r = 0.454, p = 0.045). Conversely, no significant association between mRNA levels of MMP-2 and ROM or duration of symptom was found. Conclusions: Our results suggest that both MMP-2 and TIMP-2 may be involved in the disease process of rotator cuff tears. Although the level of mRNA expression of MMP-2 and TMP-2 remain constant in torn rotator cuffs irrespective of the clinical variables, their levels may be influenced by age and defect size, which could account to change in tendon degradation and the healing process.

레이저를 이용한 Tailored Blank 용접 판재의 피로거동

오택열,권윤기,이종재,곽대순 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.4

For the Tailor Welded Blank sheet used for automobile body panel, the characteristics of fatigue strength and crack propagation behavior were studied. The thickness of specimen was joined to be same (0.9mm+0.9mm) and different (0.9mm+2.0mm). As a base test, mechanical properties around weld zone were examined. The results indicated that there were no significant decreases in mechanical properties, but hardness around weld bead was 2.3 times greater than base material. The fatigue strength was the highest when the loading direction was parallel to the welding direction, which was about 85% of tensile strength of base metal. It was decreased by 8.5% when the thickness of specimen and base metal was different, and it was increased by 25% when pre-strain was applied. The crack propagation rate was noticeably decreased around weld line and rapidly increased as it passed through weld line. Reviewing the shape of the crack propagation, crack width around weld line was wide around the weld zone due to retardation of crack growth, but it became narrow passing weld line due to decreased toughness.

Phase Evolution and Grain-Boundary Contributions in CaCu_(3-x)Zn_xTi_4O_(12)

Oh Hyeon Kwon,Byeong Kon Kim,Yeon Hwa Jo,Paul Gouri Sankar,Yul Gyo Jung,Jung Won Lee,Tae Sung Jung,조용수 대한금속·재료학회 2011 ELECTRONIC MATERIALS LETTERS Vol.7 No.4

Extensive substitutions of Zn in Ca(Cu_(1-x)Zn_x)_3Ti_4O_(12) (x = 0, 0.1, 0.5, 1.0 and 2.0) dielectrics are investigated in terms of the phase evolution, dielectric properties and grain boundary resistivity. The composition of CaCu_(2.9)Zn_(0.1)Ti_4O_(12) (x = 0.1) densified at a relatively low sintering temperature of 1000°C showed a k value of approximately 7,000 and a tanδ value of approximately 0.07 at 10 kHz, which is better than the values for pure CaCu_3Ti_4O_(12) (CCTO). The improved dielectric properties are also believed to be related to the lower grain boundary resistivity of ~1676 kΩ.cm, as obtained from a Cole-Cole plot. Beyond this level of Zn,the degradation of the dielectric constant was associated with unexpected crystalline phases, in this case Ca_2Zn_4Ti_(16)O_(38), CaTiO_3, and Zn_2TiO_4, which were observed as the level of Zn increased. Although the degradation does not match that of pure CCTO, an addition of Zn up to x=1.0 can hold the dielectric constant at the level of a few thousands, which is still promising compared to other high-k dielectric materials that must be densified below −1000°C to meet the subsequent microcircuit requirements.

A Model-Based Fault Diagnosis in Uncertain Systems

Oh Kyu Kwon,Yul Wan Sung 대한전자공학회 1990 대한전자공학회 학술대회 Vol.1990 No.01

Robust Fault Diagnosis in Uncertain Systems

Oh-Kyu Kwon,Yul-Wan Sung 대한전기학회 1993 Journal of KIEE Vol.6 No.1