• Korean Journal of Veterinary Research
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• v.45 no.4
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• pp.569-574
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• 2005

Enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to reticuloendotheliosis virus (REV) at single serum dilution was standardized. REV HI, one of the Korean field isolates, was inoculated into chicken embryo fibroblast (CEF) cells and was harvested from the culture fluids and cells after 10 to 12 days. Viruses were purified by centrifugation at the $107,000{\times}g$ for 12 hours on 20, 30, 45% (W/V) sucrose gradient. Virus specific fraction was collected and used as ELISA antigen. To standardize ELISA, the optimal concentration of coating antigen ($1{\mu}g/well$) and conjugate (1/1000) was determined by corrected OD (OD value of positive serum-OD value of negative serum) and P/N ratio (OD value of positive serum/OD value of negative serum). To calculate ELISA titer by measuring absorbance at 1/400 single serum dilution, serum titrations were carried out for various sample sera together with standard positive and negative sera. The observed titers of serum samples were plotted against sample/positive (s/p) ratios at 1/400 serum dilution. From the above data, the ELISA titers could be calculated by the equation of $log_{10}$ ELISA titer = 2.2763 ($log_{10}$ s/p) + 3.482 (r = 0.93). For evaluating the sensitivity, the standardized method were compared with conventional agar gel immunodiffusion (AGID) test method using serum samples collected from REV infected field chicken flocks. Fifty seven of 60 samples (95%) were positive for REV by ELISA, whereas only 11 (18.3%) samples were positive by AGID test. This results suggested that the ELISA tests developed in this study could be used for detection of antibodies to REV with high sensitivity.

• The Korean Journal of Nuclear Medicine
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• v.35 no.6
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• pp.364-370
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• 2001

Purpose: In the revascuarization of ischemic dysfunctional myocardium, stunned myocardium was reported to recover function earlier than hibernating myocardium. It was also suggested that stunning and hibernation could be discriminated by reversibility of perfusion impairment on myocardial SPECT. In this study, we investigated the time course of functional recover after CABG according to reversibility of perfusion impairment. Materials and Methods: In 92 patients with coronary artery disease, Tl-201 rest/dipyridamole stress Tc-99m-MIBI gated SPECT was performed before, 3 months after, and 17 months after CABG. Using a 20-segment model, segmental perfusion and systolic thickening were automatically quantified. Perfusion-impaired segments with abnormal thickening were classified by reversibility into reversible (REV) and irreversible (IRREV) groups. The proportions of function-recovered segments were compared between groups and also between 3 months and 17 months in each group. Results: A total of 129 segments were Included In the analysis, and 76 were REV and 53 were IRREV. At 3 months after CABG, 61 segments (80%) in REV group showed functional recovery while 28 segments (53%) in IRREV group did (p<0.001). However, at 17 months after CABG, 60 segments (79%) in REV group and 37 segments (70%) un IRREV group showed functional recovery (p=n.s.). When comparing 3 months and 17 months in each group, REV group showed no difference, while IRREV group showed significant further improvement (p<0.05). Conclusion: In viable myocardium with ischemic myocardial dysfunction, the segments with reversible perfusion impairment recover function earlier after revascularization than irreversible segments.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.65-65
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• 1993

봉합율의 최적 조건을 구하기 위해 다양한 방법으로 리포좀을 제조했으며, 인지질과 봉합 약물의 비는 20:1 이상이어야 하고, 리포좀 제조 방법에 따라 봉합율이 차이가 났으며, REV, REV를 freezing-thawing한 것과 SUV를 freezing-thawing한 리포좀에서 봉합율이 좋았다. REV를 freezing-thawing한 리포좀이 가장 좋았다 (66.7%, BPB; 115.7 ug trypsin/mg lipid). 콜레스테롤의 함량은 봉합율과 안정성을 고려하여 인지 질과의 비를 7.3으로 고정시켰다. 안정성은 투과성, light scattering, qucnching 등으로 측정했으며,4$^{\circ}C$,용액 상태에서 두 달 이상동안 보관했을 때 약 10% 정도가 리포좀 내에서 빠져나왔으며, 리포좀의 크기 변화는 거의 일어나지 않았다. Calcein봉합 리포좀을 Vero E6 cell에 투여했을 때, 매우 적은 양이 cell내로 들어가는 것을 형광 현미경으로 확인할 수 있었다.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.1
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• pp.54-64
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• 2006

To augment weakly damped lag mode stability of a hingeless helicopter rotor blade in hover, piezoelectric shunt with a resistor and an inductor circuits for passive damping has been studied. A shunted piezoceramics bonded to a flexure of rotor blade converts mechanical strain energy to electrical charge energy which is dissipated through the resistor in the R-L series shunt circuit. Because the fundamental lag mode frequency of a soft-in-plane hingeless helicopter rotor blade is generally about 0.7/rev, the design frequency of the blade system with flexure sets to be so. Experimentally, the measured lag mode frequency is 0.7227/rev under the short circuit condition. Therefore the suppression mode of this passive damping vibration absorber is adjusted to 0.7227/rev. As a result of damping enhancement using passive control, the passive damper which consists of a piezoelectric material and shunt circuits has a stabilizing effect on inherently weakly damped lag mode of the rotor blades, at the optimum tuning and resistor condition.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.6
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• pp.443-453
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• 2020

This study using the active vibration control technique attempts to alleviate numerically the airframe vibration of a UH-60A helicopter. The AVCS(Active Vibration Control System) is applied to reduce the 4/rev vibration responses at the specified locations of the UH-60A airframe. The 4/rev hub vibratory loads of the UH-60A rotor is predicted using the nonlinear flexible dynamics analysis code, DYMORE II. Various tools such as NDARC, MSC.NASTRAN, and MATLAB Simulink are used for the AVCS simulation with five CRFGs and seven accelerometers. At a flight speed of 158knots, the predicted 4/rev hub vibratory loads of UH-60A rotor excite the airframe, and then the 4/rev vibration responses at the specified airframe positions such as the pilot seat, rotor-fuselage joint, mid-cabin, and aft-cabin are calculated without and with AVCS. The 4/rev vibration responses at all the locations and directions are reduced by from 25.14 to 96.05% when AVCS is used, as compared to the baseline results without AVCS.

• Proceedings of the Microbiological Society of Korea Conference
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• 2003.05a
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• pp.55-58
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• 2003

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.155-158
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• 2004

To investigate the in-situ REV, cross-correlations between the ablsolute value of iu/outflux in tested boreholes and fracture frequency with various window widths were calculated. The changes of vertical flow rates can be considered as iu/outflux into/out of borehole. The results of cross-correlation analysis shows that 7m can be the most appropriate width of the appliable window.

• Journal of Chest Surgery
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• v.24 no.1
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• pp.15-25
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• 1991

From February 1988 to December 1990, 42 patients underwent so called REV operation for pulmonary stenosis or atresia with or without anomalies of ventriculoarterial connection and truncus arteriosus. The principles of operative technique are mobilization of pulmonary arterial tree beyond the pericardial reflection, transection of pulmonary trunk between the pulmonary ventricle and pulmonary artery, suture of distal pulmonary arterial stump to the upper margin of Pulmonary ventriculotomy site with absorbable suture, and anterior patch with 0.625% glutaraldehyde fixed autologous pericardium with monocusp inside it. Age at operation ranged 3-156months [mean 41.8 month] with twelve of whom infants. Operative indications were pulmonary atresia, with ventricular septal defect[16], and pulmonary stenosis with double outlet right ventricle[8], with ventricular septal defect[16], with double outlet right ventricle[8], with complete transposition of the great arteries[8], with corrected transposition of the great arteries[6], with Fallot`s tetralogy[3], and truncus arteriosus[1]. There were six hospital deaths[14%] and no late death. Twenty-four of 36 survivals were followed up more than 12 months with good clinical results. Postoperative angiocardiogram was performed in fifteen patients. Hemodynamically, two patents had residual pressure gradients along the pulmonary outflow tract, one patient showed severe pulmonary regurgitation; morphologically, there were six significant stenosis of left pulmonary arterial tree, two of whom showed significant pressure gradients. Our present experience with REV operation suggests that this technique make it possible to perform anatomic repair in a wide variety of congenital anomalies of abnormal ventriculoarterial connection associated with pulmonary outflow tract obstruction without using the prosthetic material, even in infants, with relatively low mortality and morbidity.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.7
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• pp.29-36
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• 2004

In this work, the effect of composite couplings on hub loads of a hingeless rotor in forward flight is investigated. The hingeless composite rotor blade is idealized as a laminated thin-walled box-beam. The nonclassical effects such as transverse shear, torsional warping are considered in the structural formulation. The nonlinear differential equations of motion are obtained by applying Hamilton's principle. The blade response and hub loads are calculated using a finite element formulation in space and time. The aerodynamic forces acting on the blade are calculated by quasi-steady strip theory. The theory includes the effects of reversed flow and compressibility. The magnitude of elastic couplings obtained by MSC/NASTRAN is compared with the classical pitch-flap $({\delta}3)$ or $pitch-lag({\alpha}1)$ coupling. It is found that the elastic couplings have a substantial effect on the behavior of $N_b/rev$ hub loads. Nearly 10 to 40% of hub loads is reduced by appropriately tailoring the fiber orientation angles in the laminae of the composite blade.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5457-5463
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• 2011

The objective of this study is to investigate cooling performance characteristics of mobile air conditioning system using R744 as an alternative of R-134a. In order to analyze the cooling performance characteristics of the air conditioning system using R744 for a passenger vehicle, the developed air conditioning system using R744 was applied in a real passenger vehicle and tested under various operating conditions with the variation of gas-cooler inlet air conditions, evaporator inlet air temperatures and compressor speeds. As a result, cooling capacity and coefficient of performance (COP) of the tested air conditioning system decreased with the rise of the inlet air temperature of the gas cooler but increased with the rise of the inlet air temperature of the evaporator. In addition, cooling capacity and coefficient of performance (COP) increased by 42.2 % with the rise of the compressor speed from 900 rev/min to 1800 rev/min, but it decreased by 55.4%.