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열역학 실험식에 의한 Cd-Zn계의 안정 및 준안정 상태도의 계산
崔舜惇,權海旭,金星秀 嶺南大學校 工業技術硏究所 1986 연구보고 Vol.14 No.2
For quantitative predictions of the metastable features and the compact expression of phase equilibria encountered in the extractive metallurgy of cadmium and zine, the calculations of stable and metastable equilibrium diagrams of the Cd-Zn system are made using the four parameter subregular solution model. Parameters of the thermodynamic functions are derived from the phase diagram data of "Bulletin of Alloy Phase Diagrams" and the enthalpy data of Wittig and Kleppa. Stable equilibrium diagram and thermodynamic quantities re-calculated from the optimized parameters agree with all the experimental data within the errors. Such metastable phase equilibria as the chemical spinodals, the locus of compositions and temperature where the Gibbs energies of the liquid and solid are equal(To), the metastable extensions of the solidus and liquidus curves, and metastable miscibility gaps. Excellent agreement of the calculated solvus boundary data with the experimental data is believed to provide a correct expectation of the metastable phase equilibria.
최병호,김성진,정순욱 金烏工科大學校 1998 論文集 Vol.19 No.-
Ultrathin film of 100Å-order is fabricated by Langmuir-Blodgett technique. By measure of UV-vis spectra and capacitance, deposition status was confirmed together with the thickness of natural oxidized aluminum film inside a device and dielectric constant of (N-docosyl pyridinium)-TCNQ(1:2) complex. The conductivity of this film measured by the direction of either vertical or horizontal axis is results in a quite different value.
소결조건이 소결 청동계 마찰재의 마찰특성에 미치는 영향
최병호,박노진,정순욱 金烏工科大學校 1998 論文集 Vol.19 No.-
The effect of sintering conditions(temperature and time) on the frictional properties of sintered bronze-base were investigated. It was observed that with increasing sintering temperature up to 840℃ and sintering time up to 60 min. the hardness, bending strength and coefficient of friction increased continuously, but the wear rate decreased. At sintering temperature of 860℃, however, their mechanical and frictional properties decreased rapidly due to the sweating phenomenon of tin. In our experiments, the optimal sintering condition is that sintering temperature is about 840℃ and sintering time is about 60 min.. Its average grain size is about 14.2㎛.
권순경,박상욱,최우영 한국식품영양학회 1998 韓國食品營養學會誌 Vol.11 No.5
상백피에서 추출한 단백질 분해효소의 효소적 성질을 분석하였다. 상백피 추출액으로부터 분리한 단백질 함량은 1.12mg/ml, protease는 비활성도로서 5.14U/mg 수준이었다. 효소의 기질에 대한 특이성은 casein을 100으로 하였을 때 albumin 63, collagen 58, hemoglobin 45, gelatin 36의 비율로 가수분해하여 육류 단백질에 주로 함유된 collagen, hemoglobin을 분해하는 능력이 비교적 큰 것으로 나타났다. 효소의 최적온도는 60℃, 열안정성은 50∼80℃로서 비교적 열에 안정하였다. 효소의 최적 pH는 6.0이었으며 pH 6.0∼7.0에서 안정하였고 pH 9.0 이상에서는 활성이 급격히 저하되었다. 따라서 옛날부터 가정에서 고기를 삶을 때 연회를 위하여 사용하였던 상백피 중에 단백질 분해효소력이 존재함을 확인하였다. Water extract of mulberry tree barks(Morus alba Linne) was studied for its proteolytic activity. Protein content of the extract was 1.12 ㎎/ml and its specific activity was 5.14 U/ml. The enzyme was active on various proteins : the relative acitities were 100 for casein, 63 for albumin, 58 for collagen, 45 for hemoglobin and 36 for gelatin, respectively. These suggested that the ability of the enzyme to hydrolyze meat was relatively high since those are major meat proteins. Optimum pH and temperature for proteolytic activity were : pH 6.0 and 60℃. And the enzyme was stable at the pH range of 6.0 to 7.0 and temperature between 50 and 80℃. Apparent proteolytic activities could support some scientific grounds of traditional application of mulberry tree barks to home cooking for meat tenderization.
강순용,박종진,김창욱,최성진 한국운동역학회 2001 한국운동역학회지 Vol.11 No.1
The purpose of this study is to investigate the kinematical variables of the Tkatchev motion on the horizontal bar and the effects of kinematical variables of 1 phase on 2, 3, 4 phases and the effects of kinematical characteristics of every phase on motion the air and re-grasping. The subjects Tkatchev motion were filmed with S-VHS camera at the speed of 60 fields per second and each field is digitalized to 5 fields with from the sum of handstand motion to landing. The Kwon 3D 2.1 version program is employed to obtain 3-dimensional data. Based on the results of this study, the following conclusions are drawn. 1. In the Down swing phase, the maintenance of great vertical downward velocity is an important variable to achieve large angular velocity of body center and it is also proved that the fast downward motion gives advantage in spreading body joints to get great motion power in the next Whip swing motion. 2. In the Whip swing phase, fast upward velocity and fast angular velocity of hip joint will positively affect upswing movement in t he phase. To shorten the distance between horizontal bar and body center helps effective upward motion as well. These also work beneficially in the next phase. 3. In the Releases phase, fast vertical upward velocity until pull back after curving shoulder joint and hip joint at the whip swing and large change of position of body center are important variables to perform high and long flight duration. 4. In the Re-grasp phase, the maximum spread of shoulder joint and hip and the spread of body center to the opposite direction of it helps body center to stay in higher place and to perform large circular flight motion with extended length of time. This ultimately makes effective re-grasping motion happen and connects next motion smoothly.
Azithromycin으로 치료한 임신 중 쓰쓰가무시병 1예
김광석,최진욱,서호종,김기훈,박성호,서광섭,고성만,김순혜,김호정 대한감염학회 2001 감염 Vol.33 No.5
We report a case of tsutsugamushi disease in a 26 year-old pregnant woman who was treated with azithromycin. Her gestation period was 27 weeks and she admitted with fever, rash, and eschar on the right shoulder. Currently recommended medications for the treatment of scrub typhus are doxycycline or chloramphenicol. But, these drugs are class D drugs according to the U.S. Food and Drug Administration (FDA) Fetal Risk Summary, so they couldn't be used to treat pregnant women. Recently, a few case reports suggested that azithromycin, a relatively new macrolide antibiotic, was effective and safe for the treatment of scrub typhus in pregnant women. And, there is no evidence that azithromycin causes harmful effects to the developing fetus or to children. On the basis of current in vivo test that confirms the effectiveness of azithromycin, it may be the drug of choice for the treatment of scrub typhus in pregnant women and children. (Korean J Infect Dis 33:380-382, 2001)
금속수은 폭로 근로자의 일시뇨를 이용한 생물학적 모니터링 평가
홍두루미,김순덕,염용태,최재욱 大韓産業醫學會 1996 대한직업환경의학회지 Vol.8 No.1
Biological monitoring for exposure permits estimation of organ doses or body burdens from exposures through all relevant portals of entry. Biological monitoring data may be used to estimate environmental concentrations when the latter cannot be measured directly. Biological indices are usually concentration of a chemical of its metabolites or its effect at the true receptors. Mercury concentration in urine has been most commonly recommended as a biological exposure index of mercury. for data based on urine analysis, variation in urine volume is the most significant. The urinary concentration related to excretion of the solute provides some correction for fluctuation of urine output. Sampling time must be carefully observed because distribution and elimination of a chemical are kinetic events. This study has evaluated mercury concentration in spot urine compared to the results of 24 hour collected urine by the adjustment methods(specific gravity, creatinine) and sampling time. The subjects were 43 workers who had been exposed to the metallic mercury. The results were as follows: 1. The correlation coefficients between mercury concentration in 24 hour urine and that in spot urine were 0.639-0.715 and were not different by adjustment methods. 2. In the high exposure group who were over 100ug/l of urinary mercury, the correlation coefficients between mercury concentration in 24 hour urine and that in spot urine were 0.687-0.824 and were not different by adjustment methods. 3. Mercury concentration in spot urine were very variable by sampling time or exposure time. The correlation coefficients between mercury concentration in 24 hour urine and that in spot urine were most highest as 0.85-0.91 at first voiding urine in the morning, and were 0.77-0.86 at urine collected within four hours before end of shift. In the biological monitoring to exposure of mercury, sampling of spot urine were most proper at first voiding urine in the morning, and then at urine collected within four hours before end of shift. But the adjustment methods of specific gravity and creatinine were no difference of the results.
Streptozotocin 유도 당뇨쥐에서의 Phospholipase A₂, Cyclooxygenase 활성과 Thromboxane 및 Prostacyclin합성
양정아,김성옥,최정화,곽오계,이순재,장현욱 영남대학교 약품개발연구소 1998 영남대학교 약품개발연구소 연구업적집 Vol.8 No.-
당뇨병에서의 혈전생성 기전에 관련된 주된 요인을 관찰코져 흰쥐를 4주간 사육한 후 streptozotocin(STZ)으로 당뇨를 유발한 후 6일째에 희생하여 당뇨쥐에 있어서의 phospholipase A₂ 활성변화에 따른 조직의 과산화적 손상과 혈소판 응집능 등의 변화를 관찰한 결과는 다음과 같다. 체중증가는 STZ를 투여한 후에는 STZ 투여군에서 현저하게 감소하였다. 식이섭취에 있어 STZ injection 후, DM군은 16% 증가하였다. 식이효율은 STZ injection 후 DM군은 정상군에 비해 유의적으로 감소하였다. 혈청 중의 총 지질과산화물가는 정상군에 비해 DM군은 2.5배 높았다. HDL 중의 TBARS는 정상군에 비해 DM군은 약 1.6배 정도 높았고 LDL 중의 TBARS는 정상군에 비해 DM군에서 4.8배의 높은 증가를 보였다. 혈소판 phospholipase A₂ 활성은 DM군은 정상군에 비해 42% 증가하였다. 혈소판 cyclooxygenase 활성은 정상군에 비해 DM군이 2배 정도 높은 수준이었다. 혈소판 중의 TXA₂ 농도는 정상군과 비교하여 DM군에서 169%로 현저하게 높았고 대동백 PGI₂의 농도는 정상군에 비해 DM군은 낮은 수준을 보였으며 대동맥 PGI₂와 혈소판 TXA₂의 비는 DM군에서 정상군에 비해 55% 낮았다. 결론적으로 STZ 유발 당뇨쥐에 있어서는 혈청 지질과산화물 수준의 증가와 더불어 phospholipase A₂ 활성이 증가되었으며 따라서 cyclooxygenase가 유도하는 AA cascade 활성화에 의해 TXA₂ 생성증가 및 PGI₂/TXA₂ ratio의 감소가 관찰되었다. 이러한 결과는 당뇨병 질환에서 나타나는 동맥경화증, 심혈관계 질환 등의 여러 혈관계의 병리적 현상들이 당뇨 상태에서의 지질대사 이상으로 인한 지질과산화물의 증가와 그의 독성으로 인한 여러 혈소판 관련 인자들의 활성화와 밀접하게 연관되어 나타나는 것을 시사하는 것이라 하겠다. The relation between lipid peroxidation and thrombotic reaction were investigated in streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male rats weighing 100±10gm were randomly assigned to normal and STZ-induced diabetic group(DM). Diabetes was experimentally induced by intravenous injection of 55mg/kg of body weight of STZ in citrate buffer(pH 4.3) after 4 weeks feeding of basal diet. Animals were sacrificed at the 6th day of diabetic states. Body weight gains were lower in diabetic group after STZ injection. Serum levels of thiobarbituric acid reacting substances(TBARS) that were markedly increased in DM group compared with of normal group. TBARS levles of HDL and LDL were similar patterns to total TBARS of serum. Activities of platelet phospholipase A₂(PLA₂) were higher in diabetic group than those of normal group. Activities of platelet cyclooxygenase were 106% in DM group than normal group. Platelet thromboxane A₂(TXA₂) formation was increased in DM group than normal group. Production of aortic prostacyclin(PGI₂) was lower in diabetic group than that of normal group. PGI₂/TXA₂ ratios were decreased by 55% in DM groups than those of normal group. The present results indicate that STZ-induced diabetic rats are more sensitive to oxidative stess which leads to acceleration of lipid peroxidation and platelet aggregability. In conclusion, accelerating effect of lipid peroxidation and thrombogenesis in diabetic state is regarded to be resulted from enhancement of PLA₂ activity and arachidonic acid metabolism, inhibition of antiaggregating agent and aortic PGI₂ formation.
편평세포암종 임파절 전이에 대한 인공 신경망 시스템의 진단능 평가
허민석,박태원,박상욱,유동수,이삼선,최순철 大韓口腔顎顔面 放射線學會 1999 Imaging Science in Dentistry Vol.29 No.1
Purpose: The purpose of this study was to evaluate cervical lymph node metastasis of oral squamous cell carcinoma patients by MRI film and neural network system. Materials and Methods: The oral squamous cell carcinoma patients(21 patients, 59 lymph nodes) who have visited SNU hospital and been taken by MRI, were included in this study. Neck dissection operations were done and all of the cervical lymph nodes were confirmed with biopsy. In MR images, each lymph node were evaluated by using 6 MR imaging criteria(size, roundness, heterogeneity, rim enhancement, central necrosis, grouping) respectively. Positive predictive value, negative predictive value, and accuracy of each MR imaging criteria were calculated. At neural network system, the layers of neural network system consisted of 10 input layer units, 10 hidden layer units and 1 output layer unit. 6 MR imaging criteria previously described and 4 MR imaging criteria (site I-node level II and submandibular area, site II-other node level, shape I-oval, shape II-bean) were included for input layer units. The training files were made of 39 lymph nodes(24 metastatic lymph nodes, 10 non-metastatic lymph nodes) and the testing files were made of other 20 lymph nodes(10 metastatic lymph nodes, 10 non-metastatic lymph nodes). The neural network system was trained with training files and the output level (metastatic index) of testing files were acquired. Diagnosis was decided according to 4 different standard metastatic index-68, 78, 88, 98 respectively and positive predictive values, negative predictive values and accuracy of each standard metastatic index were calculated. Results: In the diagnosis of using single MR imaging criteria, the rim enhancement criteria had highest positive predictive value (0.95) and the size criteria had highest negative predictive value(0.77). In the diagnosis of using single MR imaging criteria, the highest accurate criteria was heterogeneity (accuracy : 0.81) and the lowest one was central necrosis (accuracy : 0.59). In the diagnosis of using neural network systems, the highest accurate standard metastatic index was 78, and that time, the accuracy was 0.90. Neural network system was more accurate than any other single MR imaging criteria in evaluating cervical lymph node metastasis. Conclusion: Neural network system has been shown to be more useful than any other single MR imaging criteria. In future, Neural network system will be powerful aiding tool in evaluating cervical node metastasis.