Synthesis of Sr Doped HoCrO3 Solid Solution Systems and Their Electrical Properties

PARK, SUNG HO,Kwon, Tae Yun 한국공업화학회 2000 Journal of Industrial and Engineering Chemistry Vol.6 No.4

Ho_(1-x)SrxCrO₃ systems, with perovskite structures, were synthesized for x=0, 0.05, 0.1, 0.2 at 1300 ℃ under atmospheric pressure. The results of X-ray analysis reveals that these prepared systems forms orthorhombic structures. Also, the HoCrO₃ systems which were doped with Sr cations on the site of Ho cations, exhibited a linear increase in their cell volume. It was found that the lattice parameter and reduced volume increased as the doping level of Sr^(2+) increased. From the measurements of D.C conductivity, the activation energy obtained from the conductivity dependence on temperature was 0.18 eV. The conduction mechanism would appear to be the hopping model of electron conduction.

Korean Red ginseng prevents endothelial senescence by downregulating the HO-1/NF-κB/miRNA-155-5p/eNOS pathway

Tae-Hoon Kim,Ji-Yoon Kim,Jieun Bae,Young-Mi Kim,Moo-Ho Won,Kwon-Soo Ha,Young-Guen Kwon,Young-Myeong Kim 고려인삼학회 2021 Journal of Ginseng Research Vol.45 No.2

Background: Korean Red ginseng extract (KRGE) has beneficial effects on the cardiovascular system by improving endothelial cell function. However, its pharmacological effect on endothelial cell senescence has not been clearly elucidated. Therefore, we examined the effect and molecular mechanism of KRGE on the senescence of human umbilical vein endothelial cells (HUVECs). Methods: HUVECs were grown in normal or KRGE-supplemented medium. Furthermore, they were transfected with heme oxygenase-1 (HO-1) gene or treated with its inhibitor, a NF-κB inhibitor, and a miR-155-5p mimic or inhibitor. Senescence-associated characteristics of endothelial cells were determined by biochemical and immunohistochemical analyses. Results: Treatment of HUVECs with KRGE resulted in delayed onset and progression of senescence-associated characteristics, such as increased lysosomal acidic β-galactosidase and decreased telomerase activity, angiogenic dysfunction, and abnormal cell morphology. KRGE preserved the levels of anti-senescent factors, such as eNOS-derived NO, MnSOD, and cyclins D and A: however, it decreased the levels of senescence-promoting factors, such as ROS, activated NF-κB, endothelial cell inflammation, and p21 expression. The beneficial effects of KRGE were due to the induction of HO-1 and the inhibition of NF-κB-dependent biogenesis of miR-155-5p that led to the downregulation of eNOS. Moreover, treatment with inhibitors of HO-1, NF-κB, and miR-155-5p abolished the anti-senescence effects of KRGE. Conclusion: KRGE delayed or prevented HUVEC senescence through a signaling cascade involving the induction of HO-1, the inhibition of NF-κB-dependent miR-155-5p biogenesis, and the maintenance of the eNOS/NO axis activity, suggesting that it may protect against vascular diseases associated with endothelial senescence.

역행적 골수정 삽입술을 이용한 대퇴골 과상부 골절의 치료

권진우,신승호,조원호,성기호,김기환,손경태,이상훈,박세원,배종문,권태우 대한골절학회 2003 대한골절학회지 Vol.16 No.4

마이크로프로세서를 利用한 溫度制御

權泰夏,鄭信一,禹鐘鎬 釜山水産大學校 1982 釜山水産大學 硏究報告 Vol.22 No.2

本 論文에서는 마이크로프로세서와 溫度符號化器를 利用해서 溫度를 計數的으로 制御할 수 있는 시스템을 보다 간단히 構成하였으며 上昇기울기, 維持溫度, 降下기울기에 따라 多少의 差는 있으나 制御溫度의 變化幅이 ±0.3% 以內로 比較的 良好하게 制御되었다. bit數가 많은 A/D 變換器를 使用한다면 보다 더 精密한 溫度制御가 可能할 것이다. 現在狀態로도 實驗室의 小容量 뿐 만 아니라 産業用의 大容量 電氣爐의 溫度制御에도 利用될 수 있을 것으로 본다. This paper describes the temperature control system of an electric furnace using a SDK-85 microprocessor system as a control unit. The hardware structure of the control system was very simplified by eliminating mechanical drive portions and employing electronic circuits instead. Moreover, by employing a software method in the system desired temperature on time, i.e., rising rate, maintaining temperature and time, falling rate, can be easily controlled and changed by program. Experimental results showed the successful operation with flexibility. Temperature variation was less than ±0.3% of the desired value and was more accurate on the maintaining temperature region.

이동통신망에서의 최적 셀 할당에 관한 연구

권수태,정소영,윤상흠,김호준 전주대학교 공학기술종합연구소 2003 전주대학교 공학기술종합연구소 학술논문집 Vol.9 No.1

The paper considers a cell allocation problem in the Mobile Wireless Communication Network with limited capacity of Base Switching Center(BSC) and Mobile Switching Center(MSC), and the aim is assigning cells to BSC and MSC for supporting an efficient handoff and reducing the cabling cost. The cell assignment problem is formulated as a mixed integer programming, and a genetic algorithm is developed to derive the optimal solution. A verity of numerical problems are presented and then some interesting properties are exploited that are useful for charactering the problem.

구조화된 불확실성을 고려한 지능형 외팔보의 강인제어

권대규,방두열,소순선,유기호,이성철 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2003 工學硏究 Vol.34 No.-

This paper presents the robust control of a composite beam using μ-synthesis. The natural frequencies of the composite beam featured by a piezo-film sensor and piezo-ceramic actuator are calculated by using the modal analysis method and then modal coordinates are introduced to obtain the state equations of the structural system. Two-natural frequency were considered in the modelling, because robust control theory which has inherent robustness to structured uncertainty is adopted to suppress the transients vibrations of a glass fiber reinforced(GFR) composite beam. A robust controller satisfying the nominal performance and robust performance is designed using μ-synthesis theory based on the structured singular value. Simulations and experiments were carried out with the designed controller and effectiveness of the robust control strategy was verified by results.

신사회운동과 政治 : 政治勢力化의 요인과 쟁점 Factors and Issues for Politicking

권태환,송호근 서울대학교 사회과학연구원 2000 한국사회과학 Vol.22 No.1

이 연구의 결론에 해당하는 이 논문은 사회운동의 정치세력화의 다양한 양상을 비교론적 관점에서 권역별로 분석한 앞의 논문들의 연구결과를 종합하여 정치세력화의 개입하는 구조적 요인들을 체계화하는 데에 목적을 둔다.앞의 연구들은 '정치세력화'를 신사회 운동의 정당정치화에 국한하기보다는 어떤 결집된 형태가 아니더라도 정부와 정치권의 중대한 정책결정에 무시할 수 없는 압력을 가할 수 있는 운동형태로 규정하여 상당히 폭 넓은 입장을 취한다.'정치세력화를 향한 길'을 일차적 과정과 이차적 과정으로 구분하고, 이차적 과정을 정치세력화의 중대한 계기로 보았다.이 논문은 이차적 과정을 관할하는 가장 중요한 요인으로 '정치적' 기회구조를 지목하고, 정치적 기회구조를 지배집단의 구조와 이념적 관용의 수준, 국가의 구조, 정당구조로 세분하여 각각의 구체적 양상을 검토하였다.이러한 관점에서 본다면, 한국의 사회운동은 다른 국가들에 비하여 정치세력화의 조건이 비교적 양호하고 조직적 기반도 그런대로 괜찮은 편이다.그러나, 여전히 낙관적인 전망을 허용하는 것은 아니다. As a conclusion of this research, this paper aims at summarizing and systemizing the result of these papers published in this volume that are a comparative analysis of various aspects of politicking of civil social movements (CSMs) in East Asia, Latin America, and South Korea. This research stands upon a broad concept of the politicking of CSMs that includes dispersed claims of civilians without a visible organization that can affect governmental and political decision making. This paper divides the road to power into two consecutive stages, i.e., the first and second stages. The second stage is more decisive on the politicking than the first stage. The success and failure of the second stage relies upon the 'political opportunity structure' that consists of three important factors: the degree of ideological toleration and the structure of the ruling class, the structure of state and political party. From this standpoint, Korea's CSMS are comparatively in favorable conditions for politicking than Latin America and East Asia. But it does not still allow optimistic prediction.

종이상자포장기의 개발에 관한 연구

권경우,권병철,류봉조,명태식,박찬호,이광원 한밭대학교 산업과학기술연구소 1994 논문집 Vol.2 No.-

The paper describes the development of a new automatic wrapping machine using paper films as it has not been used so far. The most of the automatic wrapping machine have used the vinyl film causing environmental pollution, the paper films, however, have a weak point in the aspect of high temperature adhesion. Therefore, the mechanism of the existing wrapping machine should be altered to prevent it from curling effect through the technical know-how. A new method and technology reducing the curling effect in the automnatic wrapping machine are demonstrated by using developed blower. Thus it is exqection and will decrease environmental pollution.

Methanol 자화성 효모에 의한 균체 단백질 생산

권태종,이동희,정호권,최태부 건국대학교 1992 學術誌 Vol.36 No.2

SCP producing yeast JAM -3032 that has high productivity potential with methanol as carbon and energy source was isolated from soil, and conditions for SCP production, nutritional values, and alcohol oxidase of the microorganism were investigated. Isolated strain JAM-3032 was identified as Pichina on the morphological, cultural, physiological and biochemical characteristics. The production of cell mass reached at maximal level after 54 hrs cultivation at 28℃, pH 6.0 in the medium containing methanol 3.0%, yeast extract 0.8%, K2HPO4 0.1%, KH2PO4 0.1%. MgSO4ㆍ7H2O 0.05%, alanine 0.01%, nicotinic acid 0.04%, and biotin 0.04%. Dry cells of Pichia sp. JAM -3032 was composed of proteins 53.3%, carbohydrates 31. 5%, nucleic acids 5.6%, lipids 2.9%, ash 6.4% and amino acid composition of the proteins was satisfied in FAO reference. Biosynthesis of the alcohol oxidase of the strain JAM -3032 was induced by methanol. The enzyme was purified by treatment of ammonium sulfate fractionation, DEAE-Sephadex A-50 ion exchange chromatography and Sepharose 6B gel nitration. The purified enzyme was homogeneous on SDS-PAGE, and molecular weight was estimated to be about 520,000 D that was consisted of 8 subunits containing FAD as coenzyme. The optimal pH and temperature for the enzyme reaction was 7.5 and 37℃, respectively. Activation energy was 17.1Kcal/mol and half inactivating temperature was 40℃. The enzyme activity was inhibited by Ag+, Cu2+ and Hg2+ ions remarkably. The enzyme acted on methanol specifically, and its Km value was 0.89 mM.

동측에 발생한 대퇴골 경부 및 간부 골절의 치료

권진우,김기환,문상호,공규민,손경태,이상훈,권태우 대한골절학회 2003 대한골절학회지 Vol.16 No.3

목적: 동측의 대퇴골 경부 골절과 간부 골절이 동반된 경우에서 수술적 치료에 대해 본원에서 실시한 수술 방법들의 결과를 분석하였다. 대상 및 방법: 수술 후 1년 이상 추시 관찰이 가능하였던 11례를 대상으로 하였으며 경부 골절은 Garden 제 1형이 3례, 제 2형이 6례, 제 3형이 1례, 제 4형이 1례였다. 간부 골절은 중간부가 7례, 원위부가 4례였다. 추시 기간은 최소 1년 이상으로 평균 33개월이었고 11례 전부가 남자였으며 나이는 22세에서 54세로 평균 38세였다. 각 수술 방법에 따른 수술시간을 측정하였으며 방사선학으로 골유합의 시기, 부정유합, 불유합 등을 평가하였고 임상적으로는 골절부의 동통 및 관절 운동장애를 평가하였다. 결과: 치료 방법으로는 경부는 다발성 피고정술이 8례, 활강압방 고 나사못고정술이 1례였으며 간부의 경우는 중간부는 역행적 Ender정 고정술이 4례 , 금속판 고정술이 1례, 재건상 골수강내 고정술이 2례, 역행적 금속정 고정술이 1례였고, 원위부는 금속판 고정술이 1례, 역행적 교합성 금속정 고정술이 3례였다. 평균 수술시간은 재건상 골수강내 골종술이 180분, 다발성 핀고정술 및 금속판 고정술이 220분, 다발성 핀고정술 및 역행적 골수강내 고정술이 200분이었다. 골유합 기간은 간부 골절의 경우 평균 5개월이었다. 경부 골절에 대한 합병증으로는 간부 골절에 대해서 Ender정 고정술을 한 1례와 간부에 금속판 고정술을 한 후 지연진단되어 경부에 다발성 핀고정술을 한 1례에서 대퇴골두에 무혈성 괴사증이 병발하였으며 재건상 골수강내 금속정 삽입술을 한 1례에서 수술시 경부 골절의 정복소실이 있었으며 간부 골절에 대한 합병증으로는 역행적 금속정 고정술을 한 2례 (Ender정 1례와 교합성 금속정 1례)에서 불유합이 생겨서 금속판 고정술 및 자가골이식술로 대치하였다. 그리고 Ender정 고정술을 한 1례에서 지속적인 슬관절 주위 동통이 있었다. 결론: 대퇴골 경부 골절과 동측의 간부 골절이 동반된 경우의 수술적 치료에서 재건상 골수강내 금속 고정술은 기술적으로 어려움이 많아서 경부와 간부의 치료를 각각 하는 것이 기술적으로 쉬웠다. 수술시는 경부 골절의 수술을 먼저 하여도 고정에 어려움이 없었으며 간부 골절은 분쇄 골절이 많기 때문에 견고한 내고정이 필요하였다. Purpose: The purpose of this study was to analysis the result of operative treatment in ipsilateral femur neck and shaft fracuture. Material and Methods: Eleven cases of ipsilateral femur neck and shaft fractures were operated and followed more than 1 year. There were 11 men and mean age at index operation was 38 years (range 22~54). In neck fracture there were 3 of type Ⅰ, 6 of type Ⅱ, and 1 of typeⅢ according to Garden classification, shaft fractures were located an middle 1/3 (7 cases), at distal 1/3 (4 cases). We evaluated the operation time, union time, nonunion, malunion, and clinical evaluation with pain and joint stiffness. Result: In neck fractures treatment methods were 8 of multiple pinning, 2 of reconstruction nail and 1 of CHS, in shaft fractures 2 of DCP, 7 of retrograde nailing (3 Ender nail, 4 interlocking nail). The mean operation time was 180 minutes in reconstruction nail, 220 minutes in multiple pinning and DCP and 200 minutes in multiple pinning and retrograde nailing. The mean time for shaft union was 5 months. The complications were 1 case of neck reduction loss during operation in reconstruction nailing group, 1 of persistant pain around knee in Ender nailing group. Conclusion: The author think that reconstruction nail fixation is technically difficult, thus neck and shaft fracture be fixed individually. Neck fracture can be fixed first without difficulty and shaft fractures should be fixed rigidly due to comminution.