• 한국가축번식학회지
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• 제15권2호
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• pp.141-147
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• 1991

This stduy was carried out in order to investigate the effects of cryoprotective concentration and equilibration time on survival rate of ultrarapidly frozen in vitro fertilized bovine embryos. In vitro fertilized bovine embryos, following dehydration by cryoprotective agents and sucorese were directly plunged into liquid nitrogen and thawed in 38$^{\circ}C$ water. Survival rate was defined by development rate to the morula and blaqstocyst stage after in vitro culture of by FDA test. The results are summarized as follows : 1. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing medium of 0.25M sucroese added 2.0M, 2.5M, 3.0M, 3.5M, 4.0M glycerol were 75.0%, 72.0%, 67.6%, 44.8% and 18.3% respectively. 2. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing medium of 0.25M sucrose added 2.0M, 2.5M, 3.0M, 3.5M, 4.0M DMSO were 64.0%, 66.7%, 70.8%, 52.7% and 18.6, respectively. 3. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing medium of 0.25M sucrose added 2.0M, 2.5M, 3.0M, 3.5M, 4.0M propanediol were 68.4%, 64.9%, 63.2%, 62.2% and 34.7%, respectively. 4. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing medium of 2.50M glycerol added 0.1M, 0.25M, 0.5M, 0.75M, sucrose were 60.5%, 72.2%, 70.1% and 54.9%, respectively. The survival rate of in vitro fertilized embryos after ultrarapid frozen-thawing in the freezing medium of 2.5M glycerol added 0.25M sucrose were higher than concentration of 0.10M, 0.50M and 0.75M sucrose. 5. The equilibration time on the survival rate of in vitro fertilized bovine embryos was attained after short period of time(2.5~5min.) in the freezing medium added 0.25M sucrose and 3.0M DMSO higher than long period time(1~20min.).

• 한국수정란이식학회지
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• 제12권1호
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• pp.27-36
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• 1997

The studies were carried out to investigate the effects of co-culture with cumulus cells and oviduct epithelial cells on the in vitro fertilization and cleavage rate of bovine follicular cocytes and to determine the optimum thawing temperature and equilibration time on in vitro developmental rate of frozen bovine embryos. The ovaries were obtained from slaughtered Korean native cows. The follicular oocytes were cultured in TGM-199 medium containing 10 IU /ml의 PM SG, 10 IU /ml의 hCG, ip g/ml의 $\beta$-estradiol and 10% FCS for 24~48 hrs in incubator with 5% $CO_2$ in air at 38.5$^{\circ}C$. The bovine embryos following dehydration by cryoprotective agents and a various concentration of sucrose were directly plunged into liquld nitrogen and thawed in 3$0^{\circ}C$ water. Survival rate was defined as developmental rate on in vitro culture or FDA-test. The results are sunanarized as followes :1. The in vitro fertilization and in vitro developmental rates of bovine oocytes co-cultured with cumulus cells in TCM499 medium were 75.0~76.8% and 17.3~27.6%, respect-ively. And in-vitro fertilization rates of cumulus-enclosed oocytes(55.4%)were significantly(p<0.05) higher than cumulus-denuded oocytes (23.1%). 2. The in vitro fertilization and in vitro developmental rates of bovine oocytes co-cultured with l$\times$ l04cells /ml, 1 x l06cells /ml, lx l08cells /ml and 1 x l015cells /ml oviduct epithelial cells in TCM-199 medium were 74.5~77.8% and 15.7~21.20 respectively.3. The in-vitro fertilization and in vitro developmental rates of bovine oocytes cocultured in '1CM-199 media containing PMSG, hCG, PMSG+hCG. PMSG+$\beta$-estradiol, hCG+$\beta$-estradiol 0 to 40 hrs after insemination were 74.0~77.4% and l8.9~23.l%, re-spectiv ely.4.The survival rates of bovine embryos thawed after rapid freezing in the freezing medium containing a various concentration of sucrose added 1.5M and 2.OM glycerol,DMSO and propanediol were 23.5~31.4% and 20.6~34.l%, respectively. 5. The temperature thawed at 3$0^{\circ}C$ after rapid freezing of bovine embryos resulted in a significantly higher embryos survival rate than did at 2$0^{\circ}C$ and 35$^{\circ}C$.6. The equilibration time on the survival rates of bovine embryos was attained after short period of time(2.5~5 min.) in the freezing medium higher than long period of time (10~20min.). (Key words : bovine embryos, co-culture, freezing, in vitro development)

• Biomolecules & Therapeutics
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• 제7권4호
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• pp.354-361
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• 1999

In this study, the effects of tauroursodeoxycholic acid (TUDCA) on ischemia/ reperfusion injury were investigated on isolated heart perfusion models. Hezrts were perfused with oxygenated Krebs-henseleit solution (pH 7.4, $37^{\cire}C$) on a Langendorff apparatus. After equilibration, isolated hearts were treated with TUDCA 100 and 200 $\mu\textrm{M}$ or vehicle (0.02% DMSO) for 10 min before the onset of ischemia in single treatment group. In 7 day pretreatment group. TUDCA 50, 100 and 200 mg/kg body weight were given orally for 7 days before operation. After global ischemia (30 min), ischemic hearts were reperfused for 30 min. The physiological (i.e. heart rate, left ventricdular developed pressure, coronary flow, double product, time to contracture formation) and biochemical (lactate dehydrogenase; LDH) parameters were evaluated. In vehicle-treated group, time to contracture formation was 810 sec during ischemia, LVDP was 34.0 mmHg at the endpoint of reperfusion and LDH activity in total reperfusion effluent was 34.3 U/L. Single treatment with TUDCA did not change the postischemic recovery of cardiac function, LDH and time to contractur compared with ischemic control group. TUDCA pretreatment showed the tendency to decrease LDH release and to increase time to contracture and coronary flow. Our findings suggest that TUDCA does not ameliorate ischemia/reperfusion-reduced myocardial damage.

• 대한기계학회논문집B
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• 제26권10호
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• pp.1427-1435
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• 2002

The main aim of the present article is numerically to investigate the micro-scale heat transfer phenomena in a silicon microstructure irradiated by picosecond-to-femtosecond ultra-short laser pulses. Carrier-lattice non-equilibrium phenomena are simulated with a self-consistent numerical model based on Boltzmann transport theory to obtain the spatial and temporal evolutions of the lattice temperature, the carrier number density and its temperature. Especially, an equilibration time, after which carrier and lattice are in equilibrium, is newly introduced to quantify the time duration of non-equilibrium state. Significant increase in carrier temperature is observed for a few picosecond pulse laser, while the lattice temperature rise is relatively small with decreasing laser pulse width. It is also found that the laser fluence significantly affects the N 3 decaying rate of Auger recombination, the carrier temperature exhibits two peaks as a function of time due to Auger heating as well as direct laser heating of the carriers, and finally both laser fluence and pulse width play an important role in controlling the duration time of non-equilibrium between carrier and lattice.

• 한국가축번식학회지
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• 제16권2호
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• pp.117-123
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• 1992

This Study was carried out ot investigate the effects of concentration and equilibration time of cryoprotective aagents on survival rate of slowly and ultrarapidly frozen porcine embryos. The porcine embryos following dehydration by cryoprotective agents and 0.25M sucrose were slowly freezed(from 2$0^{\circ}C$ to -7$^{\circ}C$/-1$^{\circ}C$/min., from -7$^{\circ}C$ to -35$^{\circ}C$/-0.2$^{\circ}C$/min., from -35$^{\circ}C$ to -38$^{\circ}C$/-0.3$^{\circ}C$/min.) by Cell Freezer and directly plunged into liquid nitrogen and thawed in 38$^{\circ}C$ water bath. Survival rate was defined as development rate to the morula and blastocyst stage after in vitro culture or by FDA test. The results are summarized as follows : 1. The survival rates of porcine embryos after slow frozen-thawing in the freezing medium of 0.25M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 80.6, 84.7, 75.0 or 78.8%, respectively. 2. The survival rates of porcine embryos after slow frozen-thawing in the freezing medium of 0.50M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 80.9, 82.4, 73.1 or 77.1%, respectively. 3. The survival rates of porcine embryos after ultrarapid frozen-thawing in the freezing medium of 0.25M sucroese added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 65.3, 68.6, 63.2 or 59.9%, respectively. 4. The survival rates of porcine embryos after ultrapid frozen-thawing in the freezing medium of 0.50M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0 propanediol or 2.0M glycerol＋2.0M propanediol was 67.5, 62.9, 56.9, or 62.8%, respectively. 5. The higher survival rate of porcine embryos was attained at the short period ofequilibration time(5min.) in the freezing medium added 0.25M sucrose and 3.0 DMSO compared to those of 10 or 20min. equilibration time in the same condition.

• 한국환경과학회지
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• 제11권9호
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• pp.961-969
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• 2002

This study was performed : 1) to establish the experimental analysis conditions for the sorption and desorption of toxic organic contaminants to/from the activated sludge, sediment, and clay, and 2) to determine the sorption and desorption equilibrium coefficients of some representative halogenated aliphatic compounds. Through the preliminary sorption test using Azo dye, a setting of quantitative experimental conditions to determine the sorption and desorption characteristics was decided as follows; equilibration time of 180 minutes, centrifuge for 15 minutes at 5000$\times$g, and 500mg/$\ell$ of TOC concentration. The sorption and desorption characteristics of halogenated aliphatic compounds onto activated sludge, sediment and clay could be described very well using the Freundlich isotherm. The preference of the average sorption capacity of the overall compounds showed in the sequence sediment 0.26mg/g, clay 0.23mg/g, and activated sludge 0.11 mg/g. The desorption rate of the sorbed compounds onto activated sludge, sediment and clay was approximately 89.8%, 35.3%, and 66.4%, respectively.

• 구강회복응용과학지
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• 제19권1호
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• pp.49-55
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• 2003

When treating the occlusion the dentist must ensure that patients do not develop an occlusal awareness or neurosis after therapy. This means that after treatment patients should not be conscious of the dentition at rest, in occlusion, or during function. Butactually this goal is not easy to reach in daily practice. The dental technician works with rigid casts and dies that do not move. The dentist must use fixed prostheses that have been made in a laboratory setting in a clinical environment that is significantly different. In this article relativey easy cast adjustment technique which can decrease the time necessary to clinically adjust the occlusion of newly fabricated fixed prostheses, and actual occlusal equilibration technique for natural and restored dentition will be discussed.

• International Journal of Precision Engineering and Manufacturing
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• 제7권2호
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• pp.36-40
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• 2006

Diagnosis and repair tasks of an unbalanced rigid rotor reduce the chances of unexpected failure and the consequent losses in production, time, and money. This paper presents investigation of a balancing system for equilibration of rigid rotor unbalance. A practical vibration signal based method is developed for unbalance diagnosis using wavelet technology and a Lissajous diagram. This paper shows that a mass unbalance can be efficiently estimated through an appropriate narrow-band filter used to extract the required spectra component. The wavelet technology is used to design specified narrow filter bank. A modified Lissajous diagram is also introduced with statistical analysis to compute the phase position. Several experimental tests demonstrate the effectiveness in balancing the mass unbalance of a rigid rotor.

• 한국표면공학회지
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• 제21권4호
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• pp.149-159
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• 1988

Electrodeposition of chromium from low concentration chromjum (III) sulfate complexess in aqueous using sodium formate-glycine mixtures as a complexing agent was studied. In the bath formation, it is found that the optimum again temperature and time for equilibration of the electrolytes are nrcessary for 24 hrs at 45$^{\circ}C$and the optimum elecrical charge for low current electrolysis which might be produced Cr(II) ions in the electrolytes is necessary for minum 2Ah/$\ell$. The optmun concentration off standard electrolyte for main composition is 0.05M chromium(III) sulfate, 0.2M sodium formate-0.2M glycine, and I mMNaSCN as a catalysea, respectivwly. The standard electrolyte is shows good covering, good throwing power, and 6% of current efficiency (Cr(III)basis). The oppearance of electrodeposits shows att active bright chromium. The SEM morphology of the chromjum coating is observed as smooth surfaces and dispersed micro prcro pores. X-ray diffraction analysis shows a bcc structure which the perferred orintation of the chromium electrodeposits is strongin(200)plane.

• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.167-170
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• 2012

A test-area molecular dynamics simulation method for the vapor-liquid interface of argon through a Lennard-Jones intermolecular potential is presented in this paper as a primary study of interfacial systems. We found that the calculated density profile along the z-direction normal to the interface is not changed with time after equilibration and that the values of surface tension computed from this test-area method are fully consistent with the experimental data. We compared the thermodynamic properties of vapor argon, liquid argon, and argon in the vapor-liquid interface. Comparisons are made with kinetic and potential energies, diffusion coefficient, and viscosity.