• Journal of Pharmaceutical Investigation
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• 제29권3호
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• pp.211-216
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• 1999

To evaluate the thrombolytic activity of streptokinase-dextran conjugate, a rat model of arterial thrombosis was used. Briefly, the femoral artery was exposed and a filter paper saturated with 70% $FeCl_3$ solution was placed around the femoral artery in order to stop the blood flow. Six minutes after the stop of the blood flow in the femoral artery, streptokinase $(10000{\sim}30000\;units\;per\;rat)$ or streptokinase-dextran conjugate $(5000{\sim}17000\;units\;per\;rat)$ was administered by i.v. bolus injection through the femoral vein. Then the blood flow in the femoral artery was monitored using a Doppler laser flow meter. The i.v. bolus administration of streptokinase could not restore the blood flow in the femoral artery in the dose range of $10000{\sim}30000$ units per rat. The i.v. bolus administration of streptokinase-dextran conjugate could restore the blood flow in the femoral artery in the dose range of $5000{\sim}17000$ units per rat. A good correlation between the dose of streptokinase-dextran conjugate and the total thrombolytic effect was observed. In addition, the lag time between the injection of streptokinase-dextran conjugate and the restoring of the blood flow was decreased as the i.v. dose of streptokinase dextran conjugate increased. These results show the superior beneficial effect of streptokinase-dextran conjugate compared with the unconjugated streptokinase with respect to the elongation of thrombolytic activity, the administration method (single injection versus continuous infusion), and the reduced dose necessary for a equivalent thrombolytic effect.

• 한국막학회:학술대회논문집
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• 한국막학회 1993년도 추계 총회 및 학술발표회
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• pp.61-62
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• 1993

고분자 분리막의 투과성과 선택성을 향상시키기 위하여 IPN막, 고분자/액정 복합막을 다양한 기능을 가진 재료가 개발되고 있다. 본 연구에서는 알칼리메탈이온을 분리하기 위하여 고분자 지지체에 운반체로써 crown ether(macro-cyclic polyether)류를 분산시킨 고분자/운반체 복합박막을 제조하였다. 고분자/운반체 복합박막은 고분자와 운반체의 혼합용액을 수면에 전개시켜 제조하였다. 고분자는 PVC(M.W 60000, Aldrich), PS(M.W 280000, Aldrich)와 CA(M.W 30000, Sigma)를 사용하였고, 운반체로는 crown ether 중 $K^+$이온과 선택성을 가지는 18-Crown-6(Sigma)를 사용, 고분자와 18-Crown-6의 증량분을 달리하는 혼합용액을 제조하였다. 이때 용매는 Tetrahydrofuran를 사용하였다. 수면에 생성된 박막을 다공성 지지막에 적층시킨 후 감압 건조시켜 복합막을 제조하였다. 고분자와 운반체가 혼합되어 있는 용액의 점도와 표면장력을 각각 fluid spectrometer와 tensionmeter를 사용, 용액이 수면위에서 완전한 막을 형성하면서 분산될 수 있는지 조사하였으며, 고분자 지지체에 분산 고정된 운반체의 분산형태와 표면농도를 조사하기 위하여 ESCA를 이용하였다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1994년도 춘계학술대회 and 제3회 신약개발 연구발표회
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• pp.180-180
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• 1994

Farnesyl protein transferase는 Ras precursor의 C-terminal에 있는 cystein residue에 farnesyl group을 결합시키는 효소다. 이 효소를 bovine testis에서 30-50% ammonium sulfate fractionation, DEAE-sephacel ion exchange, Sephacryl s-300 gel filtration, hexapeptide(KKCVIM) affinity chromatography를 통해 30000배로 분리하였다. 분리된 효소는 gel filtration시 약 100kDa으로, SDS-polyacrylamide 전기영동시 50kDa의 인접한 두 bands로 나타났고 이것은 $\alpha$, $\beta$ subunits으로 생각되었다. $\alpha$ subunit을 encoding하는 RAM2 유전자를 site directed mutagenesis로 145번의 histidine을 aspartate로, 140번의 aspartate를 asparagine 으로 바꾸었더니 optimal pH와 $K_{m}$ 값이 변했다. Diethyl pyrocarbonate로 histidine residues를 chemical modification시켰을때 효소의 활성이 저하되었다. 145번 histidine이 aspartate로 바뀐 돌연변이효소에서 비교적 느리게 활성이 저하되므로 145번 histidine이 이 효소의 active site에 있을것으로 추측된다.

• 오토저널
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• 제15권1호
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• pp.45-54
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• 1993

The reattachment lengths of the Non-Newtonian fluid are investigated in the sudden expansion pipes whose ratios are 2.316 and 3.368, and the range of the Reynolds numbers is 100-30000. The reattachment lengths for the viscoelastic fluid in the laminar flow region are found to be much shorter than those of the Newtonian fluid, and decrease significantly with the increase of the concentration of viscoelastic fluid is two or three times longer than those of water, and gradually increases with the increase of the concentration of viscoelastic fluid.

• Clinical and Experimental Reproductive Medicine
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• 제32권4호
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• pp.353-359
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• 2005

Heterotopic pregnancy is named when an extrauterine (ectopic) pregnancy coexists with an intrauterine pregnancy simultaneously by many causes such as PID (pelvic inflammatory disease), endometriosis, IUD (intrauterine device), previous pelvic surgery and others. This is very rare in general population, with a range of occurrence estimated between 1:7963 and 1:30000. But recently the incidence has increased as the uses of ARTs (assisted reproductive technologies) including ovulation induction, IVF-ET (in-vitro fertilization and embryo transfer) and GIFT (gamete intrafallopian transfer) increase. Because this has high maternal morbidity, mortality and fetal loss, early diagnosis and proper management is very important. We report a case of heterotopic pregnancy following IVF-ET with a brief review.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권12호
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• pp.578-583
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• 2002

For ac PDP, the lifetime should be guaranted over, 30000 hours. The lifetime is correlated with the deterioration characteristics for the weakest element in ac PDP. However, the short-term deterioration test method of the at PDP has not well developed. In this paper, a short term deterioration test method of a given element in the ac PDP is proposed. By this method, MgO deterioration characteristics are investigated. The deterioration rate is decreased with MgO thickness but it was almost saturated over 5000$\AA$.

• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.2042-2052
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• 2003

An experimental study was performed to investigate heat transfer characteristics of turbulent swirling flow in an axisymmetric annuli. The static pressure, the local flow temperature, and the wall temperature with decaying swirl were measured by using tangential inlet conditions and the friction factor and the local Nusselt number were calculated for Re=30000∼70000. The local Nusselt number was compared with that obtained from the Dittus-Boelter equation with swirl and without swirl. The results showed that the swirl enhances the heat transfer at the inlet and the outlet of the test tube.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.325-329
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• 1998

This paper describes the controller for the improving speed control of the AC servo motor. The microprocessor provides an output to the difference in command. the servo system improves the characteristics of speed control. When the motor is running at the same speed as set by the reference signal, the speed encoder also provides a signal of the same frequency. Thus, the microprocessor controlled digital techniques enable to realize the flexible performance and control which was possible with time constant of linear acceleration/deceleration. We can know that optimal speed of machining center is 75msec in 30000mm/min and actually, 75msec is using on machining center. Finally experimental results prove excellent performance of this control system. This can be reduced error with more exact measure of actual speed. The system can be adaptable to CNC machine.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.347-351
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• 1998

This paper describes the controller for the improving speed control the AC servo motor. The microprocessor provides an output to the difference in command. The servo system improves the characteristics of speed control. When the motor is running at the same speed as set by the reference signal, the speed encoder also provides a signal of the same frequency. Thus, the microprocessor controlled digital techniques enable to realize the flexible performance and control which was possible with time constant. We can know that optimal speed of machining center is 75msec in 30000mm/min and actually, 75msec is using on machining center. Finally experimental results prove excellent performance of this control system. This can be reduced error with more exact measure of actual speed. The system can be adaptable to CNC machine.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.382-385
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• 2001

In the previous study, a new LTCC material in the $PbWO_{4}-TiO_{2}-B_{2}O_{3}-CuO$ system was introduced. The developed material can be sintered at $850^{\circ}C$ and its dielectric properties are $\varepsilon_{r}=20-25$, $Q{\times}f_{o}=30000\sim50000GHz$, and $\tau_{f}=0.2{\sim}30ppm/^{\circ}C$, respectively. Therefore this material can be used as a LTCC substrate material for fabrication of multilayered high frequency communication module set. In present study, using this material, tape casting condition was established. With this condition, a multilayered resonator was fabricated and its electrical properties were examined. In present study, an antenna-duplexer module was also fabricated. Frequency characteristics of as-fabricated antenna-duplexer module was compared with simulation results.