수용액 및 물-유기용매 혼합용매에서의 Hg$^{2+}$ 에 의한 Co(Ⅲ) 착물의 수화반응

오창언,윤두천,도명기,Oh Chang Eon,Yoon Doo Cheon,Doh Myung Ki 대한화학회 1990 대한화학회지 Vol.34 No.5

Observed rate constants (k$_{obs.}$) for Hg$^{2+}$-catalysed aquation of cis-[Co(en)$_2$(OH$_2$)Cl]$^{2+}$, [Co(NH$_3$)$_5$Cl]$^{2+}$, cis-[Co(NH$_3$)$_4$(OH$_2$)Cl]$^{2+}$, and [Co(NH$_2$CH$_3$)$_5$Cl]$^{2+}$ were measured at various concentrations of Hg$^{2+}$. The k$_{obs.}$ was increased with increasing the concentrations of Hg$^{2+}$. The k$_{obs.}$ were related to mechanistically derived rate constants by the relationship; Rate = k$_2$K[complex][Hg$^{2+}$]. Various mixed aqueous-organic solvent have been successfully employed for Hg$^{2+}$-catalysed aquation of octahedral myetal complexes. From the slope of the plot of log k againt Y (solvent ionizing power), the mechanism on the aquation of Co(Ⅲ) complexes by Hg$^{2+}$ has been suggested to be I$_d$-mechanism. The change in a rate on aquation of each Co(Ⅲ) complex was related to the ligand field parameters (${\Delta}$), for Co(Ⅲ) complexes. 촉매로서 Hg$^{2+}$을 사용한 수화반응에서 cis-[Co(en)$_2$(OH$_2$)Cl]$^{2+}$, [Co(NH$_3$)$_5$Cl]$^{2+}$, cis-[Co(NH$_3$)$_4$(OH$_2$)Cl]$^{2+}$ 및 [Co(NH$_2$CH$_3$)$_5$Cl]$^{2+}$착물들은 Hg$^{2+}$의 농도가 증가할수록 관측속도상수(k$_{obs}$)의 값이 증가하였다. Hg$^{2+}$에 의한 수화반응의 속도법칙은 Rate = k$_2$K[complex][Hg$^{2+}$]이었고, 그 메카니즘이 연구되었다. 또한 여러가지 유기용매-물 혼합용매에서 Co(Ⅲ)착물의 Hg$^{2+}$에 의한 수화반응이 연구되었다. 용매의 성질인 Y (solvent ionizing power)값에 대한 log k를 도시하여 그 기울기인 m값을 얻었다. 그 m값으로부터 수화반응의 메카니즘을 추정하였다. 속도론적인 자료로부터 Hg$^{2+}$에 의한 Co(Ⅲ)착물의 수화반응이 I$_{d^-}$메카니즘으로 제안되었다. 각 Co(Ⅲ)착물의 속도의 차이는 여러가지 리간드가 배위된 Co(Ⅲ)착물의 리간드장파라메타(${\Delta}$)값과 관계가 있었다.

수용액에서 $Hg^{2+}$에 의한 trans-[Co(3,2,3-tet)X$_2]^+$ (3,2,3-tet = 4,7-diazadecane-1,10-diamine, $X_2\;=\;Cl_2,\;(NO_2)Cl,\;Br_2,\;(NO_2)Br,\;(NO_3)_2)$ 착물의 아쿠아 반응

윤두천,오창언,도명기,Doo Cheon Yoon,Chang Eon Oh,Myung Ki Doh 대한화학회 1993 대한화학회지 Vol.37 No.11

수용액상에서 $Hg^{2+}$에 의한 trans-[Co(3,2,3-tet)$X_2]^+$ (3,2,3-tet = 4,7-diazadecane-1,10-diamine, $X_2\;=\;Cl_2,\;(NO_2)Cl,\;Br_2,\;(NO_2)Br,\;(NO_3)_2)$ 착물의 아쿠아 반응이 연구되었다. 생성물을 확인하고 반응메카니즘을 추정하기 위하여 크로마토그래피를 사용하였고 전자흡수 스펙트럼을 측정하였다. 그 결과 네자리 리간드인 3,2,3-tet가 배위된 여러가지 $trans-[Co(3,2,3-tet)X_2]^+$ 착물은 각각 아쿠아된 trans-[Co(3,2,3-tet)$(OH_2)_2]^{3+}$ 착물을 거쳐 cis-${\beta}$-[Co(3,2,3-tet)$(OH_2)_2]^{3+}$ 착물이 생성되었다. $Hg^{2+}$에 의한 trans-$[Co(3,2,3-tet)Cl_2]^+$ 착물과 trans-[Co(3,2,3-tet)$(NO_2)Cl]^+$ 착물의 아쿠아 반응에 대한 메카니즘을 추정하기 위하여 속도론적 조사를 하였따. 그 결과 $trans-[Co(3,2,3-tet)Cl_2]^+$ 착물은 D(dissociative)-메카니즘으로 진행되었고, trans-[Co(3,2,3-tet)$(NO2_)Cl]^+ $착물은 $I_d$(interchange dissociative)-메카니즘으로 진행되었다. 그리고 입체화학적인 거동을 조사하기 위하여 라세미(R,R:S,S)3,2,3-tet 대신에 키랄성이 R,R인 3,2,3,-tet를 배위시킨 trans-$[Co(R,R-3,2,3-tet)Cl_2]^+$ 착물에 $Hg^{2+}$를 용리시켰을 때 아쿠아 반응에 대한 원편광이색성(circular dichroism) 스펙트럼을 측정하여 그 절대구조를 확인한 결과 ${\Delta}-cis-{\beta}$-[Co(R,R-3,2,3-tet)$(OH_2)_2]^{3+}$ 착물이 생성되었다. $Hg^{2+}$-induced aquation trans-[Co(3,2,3-tet)$X_2]^+$(3,2,3-tet = 4,7-diazadecane-1,10-diamine, $X_2\;=\;Cl_2,\;(NO_2)Cl,\;Br_2,\;(NO_2)Br,\;(NO_3)_2)$ complexes was investigated in aqueous solution. The products and the reaction mechanism were confirmed by chromatography, UV/Vis. spectrum, and circular dichroism (CD) spectrum. From the results, $Hg^{2+}$-induced aquation of 3,2,3-tet system has been produced cis-${\beta}$ complex via trans complex. The kinetic studies on $Hg^{2+}$-induced aquation of trans-[Co(3,2,3-tet)$Cl_2]^+$ complex and trans-[Co(3,2,3-tet)$(NO_2)Cl]^+$ complex were also carried out to study the reaction mechanism. The results show that trans-[Co(3,2,3-tet)$Cl_2]^+$ complex undergoes the D(dissociative)-mechanism and trans-[Co(3,2,3-tet)$(NO_2)Cl]^+$ complex $I_d$(interchange dissociavite)-mechanism. In order to confirm steric course for the reaction mechanism, $Hg^{2+}$-induced aquation on trans-[Co(R,R-3,2,3-tet)$Cl_2]^+$ complex to which chiral R,R-3,2,3-tet was coordinated instead of the racemic(R,R:S,S) 3,2,3-tet was used has been examined by CD spectrum. From the results, the final complex was confirmed to be ${\Delta}-cis-{\beta}$-[Co(R,R-3,2,3-tet)$(OH_2)_2]^{3+}$ complex indicating the chirality was retained through whole process.

The HBV DNA Amounts in Serum Have No relationship with ALT level and Hetergeneous Population Coexits in Chronic Hepatitis B Virus Infection

Chun, Yoon-Keun,Ha, Joo-hun,Hong-Jung-Woo,Oh, Soo-Myung,Kim, Sung-Soo 경희대학교 동서의학연구소 1999 INTERNATIONAL SYMPOSIUM ON EAST-WEST MEDICINE Vol.1999 No.1

Yoon-Keun Chun¹,Joohun Ha□Hong-Jung Woo□, Soo Myung Oh□,Sung Soo Kim□ ¹Department of Molecular Biology, College of Medicine,²Department of Surgery, college of Medicine,³Department of Internal Medicine, College of Oriental Medicine,and ⁴East-Weat Medical Reserch Institute,Kyung Hee University, Seoul, Korea. The HBV DNA Amounts in Serum Have No relationship with ALT level and Hetergeneous Population Coexits in Chronic Hepatitis B Virus Infection. Proceedings of International Symposium on East-West Medicine, Seoul. 212-230, 1999. -Hepatitis B is caused by hepadnavirus. Hepatitis B virus replicates through 3.5kb pregenomic RNA intermediate which is regulated by core promoter. Pathogenesis of hepatitis B virus has been bilieved the result of host immune response. But recently many studies have reported that high level of viral replication caused by mutation in core promoter might result in severs hepatitis. But these studies were performed in vitro, not in vivo. So there is yet debate about which factor, viral of host factor, is more important in pathogenesis of hepatitis B virus. So we measured real viral replication level in 204 chronic hepatitis B patients by quantifying HBV DNA from sera by our novel PCR-based more sensitive method, and compared these results with ALT level measured from same sera, which indicates liver cell damage. Surprisingly there are no significant correlation between HBV DNA quantity and ALT level. Then we cloned core promoter region. In SSCP, we found that many viral mutants coexist in one patient. Base on SSCP result, we chose main viral core promoter type in each patients, which is thought to determine overall viral replication level in this patient. Main type of core promoter region of each 41 patients were directly sequenced. And with these we measured promoter activity by luciferase assay system and compared promoter activity with on another. We found tha there were some differences in promoter activity according to core promoter sequences. And we constructed replication-competent viral constructs with core promoter from 41 patients and Transfected these into HepG2 cell and measured HBV DNA by southern blot. There were also differences in HBV DNA quantity according to core promoter sequences. On these all results we investigated correlation between the effect of HBV core promoter on viral replication in vitro and HBN DNA quantity, ALT level from sera of each patients. We found there is no significant correlation among them. As a result, we concluded that in determining severity chronic hepatitis B patients, host factors of each patient is more important rather than replicative activity of virus itself.

급성전골수성백혈병에서 백혈구성분채집술에 이은 치명적인 뇌출혈 2예

오윤정,박소윤,김윤정,한동석,김현수,최진혁,남동기,임호영,김효철,주희재 아주대학교 의과학연구소 1998 아주의학 Vol.3 No.1

The aim of this study is to report 2 cases of acute promyelocytic leukemia who died from intracranial hemorrhage following leukapheresis and to provide proper preventive measures against hemorrhage following leukapheresis. From 1994 to 1997, a total of twenty-six patients with leukemia underwent leukapheresis to control hyperleukocytosis at Ajou University Hospital. Two patients with acute promyelocytic leukemia received all-trans retinoic acid but developed drug-induced hyperleukocytosis. Shortly after leukapheresis, they died from intracranial hemorrhage. The risk factors for fatal hemorrhage are thought to be coexisting disseminated intravascular coagulation(DIC), thrombocytopenia aggravated by leukapheresis, exacerbated coagulopathy related to mechanical trauma through leukapheresis and the excess use of citrate during leukapheresis. To reduce the risk of the bleeding associated with leukapheresis, it is necessary to replace platelet sufficiently before and after leukapheresis and to give calcium to correct coagulopathy induced by excess citrate which is used as anticoagulant as well as the correction of disseminated intravascular coagulation.

Acoustic excitation effect on NO_x reduction and flame stability in a lifted non-premixed turbulent hydrogen jet with coaxial air

Oh, J.,Heo, P.,Yoon, Y. Pergamon Press ; Elsevier Science Ltd 2009 International journal of hydrogen energy Vol.34 No.18

The effects of acoustic excitation on the reduction in nitric oxidant (NO<SUB>x</SUB>) emission were experimentally investigated in non-premixed lifted hydrogen jet flames with coaxial air. The purpose of the present work was to analyze the acoustic forcing effect on the flow field, the reaction zone, and NO<SUB>x</SUB> emission, and to study the mechanisms of NO<SUB>x</SUB> reduction and flame stabilization. To analyze of the flow field, a PIV method was used that incorporated two Nd-YAG lasers and a CCD camera. The reaction zone was visualized by taking OH* chemiluminescence images with a 307.1 +/- 5 nm narrow band pass filter and an ICCD camera. A flow condition was carefully selected at u<SUB>F</SUB> = 150, 200, 250 m/s and u<SUB>A</SUB> = 12, 16, 20 m/s, which was sustainable for acoustic excitation in a lifted flame region. The frequency was swept from 150 to 1000 Hz in 5 Hz steps. From the measurements of the flow field, the reaction zone, and NO<SUB>x</SUB> emission, we concluded that NO<SUB>x</SUB> emission was reduced and minimized at the resonance frequency. The vortex that was generated by acoustic forcing promoted air entrainment and enhanced the fuel-air mixing rate. This premixing effect resulted in a lower flame temperature, and thus lower NO<SUB>x</SUB> emissions. In addition, the liftoff height periodically fluctuated due to the stretch effect as the vortex interacted with the flame base.

A STUDY ON THE EXPLOSION SAFETY ASSESSMENT OF HYDROCARBON REFRIGERANT REFRIGERATOR

Oh,Kyu-Hyung,Kim,Min-Kyu,Chu,Euy-Sung,Lim,Byung-Han,Kim,Man-Hoe,Park,Yoon-Ser 한국화재소방학회 1997 한국화재소방학회 학술대회 논문집 Vol.1997 No.-

This paper discribes an experimental explosion risk assessment study on refrigerators containing flammable hydrocarbon refrigerant. A refrigerator used in this study is a larder fridge type, 215 liter in volume. The hydrocarbon refrigerant used in the refrigerator is iso-butane(C<TEX>$_4$</TEX>H<TEX>$_{10}$</TEX>). For the explosion safety assessment of the refrigerator, temperature of compressor, cooling air circulation fan motor, defrost heater and inner lamp were measured during the operation. And to confirm the ignitablity of flammable gas by the electric spark of the switches of the refrigerator, ON-OFF test of all switches were conducted with compulsorily near the stoichiometric concentration atmosphere of iso-butane-air mixture. As the result of experiment above mentioned and another experiment for the explosion safety assessment, we can conclude that explosion hazard in connection with the use of hydrocarbon refrigerant was few.w.

두가지 혈류 유발방법에 의한 새로운 심폐소생술(이중 혈류 유발 심폐소생술)장치의 개발

황성오,김현,조준휘,오범진,임종천,최경훈,윤정한,이승환,김영식,이강현,이윤선 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Background: There have been many efforts to augment blood flow during cardiopulmonary resuscitation. These efforts have focused on maximizing the effect of cardiac pump or thoracic pump alone. However, considering that the heart is the biggest blood reservoir and increase of intrathoracic pressure can generate blood flow, simultaneous exploitation of both mechanisms may have synergistic effect. We hypothesized that simultaneous chest constriction in addition to sternal compression by standard CPR may have additive hemodynamic effects by preventing deformation of the chest and increase of intrathoracic pressure. Methods and results: we built a new mechanical device to perform compression and thoracic constriction simultaneously. The device consists of two main elements. Piston in the center is to depress the sternum. Strap is to constrict the thorax circumferentially. Strap is attached to both sides of the piston. When the piston is pushed down, it depresses the sternum and pulls on the thoracic strap. To determine strap width to produce optimal hemodynamic effect, we measured hemodynamic parameters with variable widths of strap in two dogs after induction of ventricular fibrillation. Result of the experiment showed that 10cm wide strap was determined to be most effective. We also determined optimal depth of compression to produce maximal hemodynamic effect with animal experiments using two dogs. Animal experiments showed that the highest aortic pressure could be generated when the stemum was depressed to 5 cm. Cardiopulmonary resusciation using a new device could generate higher systolic aortic pressure, coronary perfusion pressure and end-tidal carbon dioxide tension in comparison with standard cardiopulmonary resuscitation in a pilot animal study using two dogs. Conclusion: New cardiopulmonary resuscitation method using a mechanical device designed by us could perform sternal compression and simultaneous thoracic constriction, and generate better hemodynamic effects than standard cardiopulmonary resuscitation in pilot animal experiments.

성인에서 장기간 Furosemide오용과 연관된 신수질 석회화

김윤구,이윤하,이규백,장세호,김대중,오하영,김보현,김미경,조윤숙 대한신장학회 1996 대한신장학회잡지 Vol.15 No.4

음파가진이 부상된 수소 난류 확산화염에 미치는 영향

오정석(Jeongseog Oh),허필원(Pilwon Heo),윤영빈(Youngbin Yoon) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5

The effects of acoustic excitation on the reduction in nitric oxidant (NOx) emission were experimentally investigated in non-premixed lifted hydrogen jet flames with coaxial air. The purpose of this work was to find an effective method to reduce NOx emission, to analyse the acoustic forcing effect on the flow field, the reaction zone, and NOx emission, and to study NOx reduction mechanisms. For the analysis of the flow field, a PIV method was used that incorporated two Nd-YAG lasers and a CCD camera. The reaction zone was visualized by taking OH<SUP>*</SUP> chemiluminescence images with a 307.1±5 ㎚ narrow band pass filter and an ICCD camera. A flow condition was carefully selected at uF=200 ㎧ and uA=16 ㎧, which was sustainable for the acoustic excitation in a lifted flame region. The frequency was swept from 150 to 1000 ㎐ in 5 ㎐ steps. And then NOx emissions were detected with a NOx sensor and recorded in a DAQ system. From the measurements of the flow field, the reaction zone, and NOx emission, we concluded that NOx emission was reduced and minimized at a resonance frequency. The vortex that was generated by acoustic forcing promoted air entrainment and enhanced fuel-air premixing. This premixing effect resulted in a lower flame temperature, and thus, a lower NOx emission.

Superconducting MgB2 Wire Drawing Considering Anisotropic Hardening Behavior and Hydrostatic Effect

Young‑Seok Oh,Ho Won Lee,Kook‑Chae Chung,Duck‑Young Hwang,Seong‑Hoon Kang,Jeong Whan Yoon 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

Numerical modeling was conducted to investigate the deformation behavior of powder mixture during multi-pass drawingprocesses for multi-filamentary MgB2wire. A modified Drucker-Prager Cap (DPC) model with an elliptical cap surface usingthe new material characterization method was developed to capture the anisotropic hardening behavior and hydrostatic effectof the powder mixture. A number of uniaxial die compaction, cold isostatic pressing, diametrical compression, and uniaxialcompression tests were conducted using different powder densities to characterize the modified DPC model. A commercialfinite element software ABAQUS with a user subroutine was used to simulate the drawing of the MgB2wire. The densityand area fraction of the powder mixture during the wire-drawing process were verified with experimental results. The differencein packing density at the inner and outer filaments of the MgB2wire was successfully captured by simulation. Inaddition, the effect of the initial packing density on the superconducting properties of MgB2wire was numerically studied. It is shown that the increase in the superconducting area, which results from a high initial packing density, should be moreeffective compared to the increase in the grain connectivity in enhancing the critical current properties for the MgB2wirewhen the final packing density is saturated after a number of drawing processes.