• Clinical and Experimental Reproductive Medicine
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• v.45 no.1
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• pp.25-30
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• 2018

Objective: This study conducted a preliminary examination of the effects of three-area laser-assisted zona thinning (LAZT) during the cleavage stage of embryo development on the hatching process in human in vitro fertilization-embryo transfer (IVF-ET) with subjects of advanced female age or frozen-thawed (FT) embryos. Methods: Eight-cell stage embryos were treated with LAZT in three areas of the zona pellucida at $120^{\circ}$ intervals. The control group was embryos without LAZT. Of the 72 consecutive fresh cycles and the 28 FT embryo transfer cycles, the patients in 55 fresh cycles and 17 FT cycles declined LAZT, and those cycles were defined as the control group. Results: In the fresh cycles, the pregnancy rates were similar in the LAZT and control groups. However, in the FT cycles, the pregnancy rate was significantly higher in the LAZT group than in the control group (45.5% in the LAZT group vs. 23.5% in the control group, p< 0.05). Conclusion: These results show that multi-area LAZT resulted in significantly improved pregnancy outcomes in human 8-cell embryos compared to controls.

• Clinical and Experimental Reproductive Medicine
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• v.13 no.1
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• pp.67-75
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• 1986

Follicle monitoring in the normal and clomiphene·stimulated cycles were analyzed in the Seoul IVF and ET (In vitro fertilization and embryo transfer) program. Ovarian follicular diameters were measured by the real·time sector scanner and plasma estradiol levels were assayed by radioimmunoassay methods during periovulatory period. The maximum follicular sizes of the clomiphene-stimulated and normal cycles were 21.1+-3.4mm and 19.2+-0.8mm, respectively. The peak levels of plasma estradiol in the clomiphene-stimulated and normal cycles were 10538+-553.6ng/ml and 298.3+-39.6pg/ml, respectively. Daily growth rate of the follicular diameters of the clomiphene-stimulated and normal cycles were 2.1mm and 1.9mm, respectively. Mean follicular number of the clomiphene-simulated and normal cycles were 2.28+-1.12 and 1.12+-0.21, respectively. There was a good statistical correlation between the mean follicular diameters and the plasma estradiol levels in the normal ovulatory and c1omiphene-stimulated ovulatory menstrual cycles (p<0.05). Our data revealad that the mean follicular diameter and the plasma estradiol level prior to HCG administration in IVF and program should reach at the level of 17.8+-3.0mm and 949.4+-487.1 pg/ml, respectively.

• Transactions of Materials Processing
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• v.27 no.6
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• pp.347-355
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• 2018

This study investigated the effects of the processing number of multi-axial diagonal forging (MADF) on the microstructural changes of OFC fabricated by MADF processes. The as-extruded OFC was cut to $25mm^3$ cube for the MADF processes. The MADF process consists of plane forging with a thickness reduction of 30% and diagonal forging with a diagonal forging angle of $135^{\circ}$. In order to analyze the microstructural evolutions according to the number of repetitions, 1, 2, 3 and 4 cycles of the MADF process were performed. OFC specimens were successfully deformed without surface cracking for up to 4 cycles of MADF. The grain size, average misorientation and average grain orientation spread (GOS) of MADF processed materials were analyzed using EBSD technique and their Vicker's hardness were also measured. The results showed that MADF process effectively refined the microstructure of OFC with initial average grain size of $84.2{\mu}m$. The average grain sizes of specimens MADF processed for 1, 2, 3, 4 cycles were refined to be $8.5{\mu}m$, $2.2{\mu}m$, $1.5{\mu}m$, $1.1{\mu}m$, respectively. The grain refinement seemed to be saturated when OFC was MADF processed over 2 cycles. In the case of specimens subjected to two or more cycles of MADF, the degree of decrease in average grain size was drastically reduced as the number of cycles increased due to softening phenomena such as dynamic recovery or dynamic recrystallization during processing. The degree of increase in average Vicker's hardness was also dramatically reduced as the number of cycles increased due to the same reason.

• Geomechanics and Engineering
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• v.38 no.3
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• pp.249-260
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• 2024

In order to study the mechanical propertied and change rules of undrained shear behavior of saline soil under the freeze-thaw cycles, an improved constitutive model reflecting the effects of freeze-thaw cycles was proposed based on the traditional Duncan-Chang model. The saline soil in Qian'an County, western Jilin Province, was selected as the experimental object. Then, a set of freeze-thaw cycles (0, 1, 10, 30, 60, 90, 120) tests were conducted on the saline soil specimens, and conventional consolidated undrained triaxial shear tests were conducted on the saline soil specimens that underwent freeze-thaw cycles. The stress-strain relationship was obtained by the triaxial shear test. The model parameters have a corresponding regression relationship with the number of freeze-thaw cycles. Finally, based on the function expression of the model parameters, the modified Duncan-Chang model with the number of freeze-thaw cycles as the influence factor was established, whilst the calculation program of the modified model is compiled. Based on the test results, the stress-strain relationship of the saline soil specimen shows strain hardening. The shear strength gradually decreases with the increase of freeze-thaw cycle. The 10 freeze-thaw cycles are the turning point in the trend of changes of the mechanical properties of saline soils. The calculated and experimental stress-strain relationship are compared, and the comparison between the calculated value of the model and the experimental value showed that the two had a good consistency, which verified the validity of the modified Duncan-Chang model in reflecting the effects of the freeze-thaw cycle.

• Clinical and Experimental Reproductive Medicine
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• v.43 no.3
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• pp.169-173
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• 2016

Objective: To determine the preferred regimen for women with adenomyosis undergoing in vitro fertilization (IVF), we compared the IVF outcomes of fresh embryo transfer (ET) cycles with or without gonadotropin-releasing hormone (GnRH) agonist pretreatment and of frozenthawed embryo transfer (FET) cycles following GnRH agonist treatment. Methods: This retrospective study included 241 IVF cycles of women with adenomyosis from January 2006 to January 2012. Fresh ET cycles without (147 cycles, group A) or with (105 cycles, group B) GnRH agonist pretreatment, and FET cycles following GnRH agonist treatment (43 cycles, group C) were compared. Adenomyosis was identified by using transvaginal ultrasound at the initial workup and classified into focal and diffuse types. The IVF outcomes were also subanalyzed according to the adenomyotic region. Results: GnRH agonist pretreatment increased the stimulation duration ($11.5{\pm}2.1days$ vs. $9.9{\pm}2.0days$) and total dose of gonadotropin ($3,421{\pm}1,141IU$ vs. $2,588{\pm}1,192IU$), which resulted in a significantly higher number of retrieved oocytes ($10.0{\pm}8.2$ vs. $7.9{\pm}6.8$, p=0.013) in group B than in group A. Controlled ovarian stimulation for freezing resulted in a significantly higher number of retrieved oocytes ($14.3{\pm}9.2$ vs. $10.0{\pm}8.2$, p=0.022) with a lower dose of gonadotropin ($2,974{\pm}1,112IU$ vs. $3,421{\pm}1,141IU$, p=0.037) in group C than in group B. The clinical pregnancy rate in group C (39.5%) tended to be higher than those in groups B (30.5%) and A (25.2%) but without a significant difference. Conclusion: FET following GnRH agonist pretreatment tended to increase the pregnancy rate in patients with adenomyosis. Further largescale prospective studies are required to confirm this result.

• Journal of Hydrogen and New Energy
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• v.22 no.3
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• pp.402-408
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• 2011

Organic Rankine cycles (ORC) can be used to produce power from heat at different temperature levels available as geothermal heat, as biogenic heat from biomass, as solar or as waste heat. In ORC working fluids with relatively low critical temperatures and pressures can be compressed directly to their supercritical pressures and heated before expansion so as to obtain a better thermal match with their heat sources. In this work thermal performance of ORC with and without an internal heat exchanger is comparatively investigated in the range of subcritical and transcritical cycles. R134a is considered as working fluid and special attention is paid to the effect of turbine inlet pressure on the characteristics of the system. Results show that operation with supercritical cycles can provide better performance than subcritical cycles and the internal heat exchanger can improve the thermal efficiency when the temperature of heat source becomes higher.

• Transactions of Materials Processing
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• v.14 no.1 s.73
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• pp.71-77
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• 2005

Thermal stability and dry sliding wear behavior of ultra-fine grained 6061 Al alloy fabricated by an accumulative roll-bonding (ARB) process have been investigated. After 4 ARB cycles, an ultra-fine grained microstructure of the 6061 Al alloy composed of grains with average size of 500nm, and separated mostly by high-angle boundaries was obtained. Though hardness and tensile strength of the ARB processed Al alloy increased with ARB cycles up to 4 cycles, the processed alloy exhibited decreased ductility and little strain hardening. Thermal stability of the ARB-processed microstructure was studied by annealing of the severely deformed alloy at $423K{\sim}573K$. The refined microstructure of the alloy remained stable up to 473K, and the peak aging treatment of the alloy at 450K for 8 hrs increased the thermal stability of the alloy. Sliding-wear rates of the alloy increased with the number of ARB cycles in spite of the increased hardness with the cycles. Wear mechanisms of the ultra-fine grained alloy were investigated by examining worn surfaces, wear debris, and cross-sections by a scanning electron microscopy (SEM).

• Clinical and Experimental Reproductive Medicine
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• v.16 no.1
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• pp.93-101
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• 1989

71 cycles of 67 women were treated for superovulation induction in our IVF & ET program from May to September in 1988. Endogenous LH surges were occurred in 21 cycles out of 71 cycles. And then, we selected 50 cycles without endogenous LH surge treated in the same period as control group. We compared egg recovery rate, egg maturity, fertilization rate, cleavage rate and pregnancy rate of study group with those of control group. We were able to detect more than 90% of endogenous LH surge by commencing daily LH monitoring on MCD 9. The egg recovery rate, egg maturity, fertilization rate, and pregnancy rate of the study group were not statistically different from those of the control group. Significantly lower cleavage rate was seen in the study group compared with that of control group. Above results suggested that the cycles with endogenous LH surge do not have to be abandoned and can be treated continuously to achieve successful pregnancy.

• Structural Engineering and Mechanics
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• v.28 no.5
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• pp.495-514
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• 2008

In this paper, experimental and theoretical investigations of the effect of the mean moment on the response and collapse of circular thin-walled tubes subjected to cyclic bending are discussed. To highlight the influence of the mean moment effect, three different moment ratios r (minimum moment/ maximum moment) of -1, -0.5 and 0, respectively, were experimentally investigated. It has been found that the moment-curvature loop gradually shrinks with the number of cycles, and becomes stable after a few cycles for symmetric cyclic bending (r = -1). However, the moment-curvature loop exhibits ratcheting and increases with the number of cycles for unsymmetric cyclic bending (r = -0.5 or 0). In addition, although the three groups of tested specimens had three different moment ratios, when plotted in a log-log scale, three parallel straight lines describe the relationship between the controlled moment range and the number of cycles necessary to produce buckling. Finally, the endochronic theory combined with the principle of virtual work was used to simulate the relationship among the moment, curvature and ovalization of thin-walled tubes under cyclic bending. An empirical formulation was proposed for simulating the relationship between the moment range and the number of cycles necessary to produce buckling for thin-walled tubes subjected to cyclic bending with different moment ratios. The results of the experimental investigation and the simulation are in good agreement with each other.

• Applied Science and Convergence Technology
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• v.24 no.3
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• pp.67-71
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• 2015

InP/InGaP quantum structures (QSs) were grown on GaAs (001) substrates by a migration-enhanced molecular beam epitaxy method. Temperature-dependent photoluminescence (PL) and emission wavelength-dependent time-resolved PL (TRPL) were performed to investigate the optical properties of InP/InGaP QSs as a function of migration enhanced epitaxy (MEE) growth cycles from 2 to 8. One cycle for the growth of InP QS consists of 2-s In and 2-s P supply with an interruption time of 10 s after each source supply. As the MEE growth cycle increases from 2 to 8, the PL peak is redshifted and exhibited different (larger, comparable, or smaller) bandgap shrinkages with increasing temperature compared to that of bulk InP. The PL decay becomes faster with increasing MEE cycles while the PL decay time increases with increasing emission wavelength. These PL and TRPL results are attributed to the different QS density and size/shape caused by the MEE repetition cycles. Therefore, the size and density of InP QSs can be controlled by changing the MEE growth cycles.