• Tribology and Lubricants
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• 제11권5호
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• pp.26-30
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• 1995

Sliding experiments have been conducted on alumina and silicon carbide ceramics. Wear and friction data of both materials indicate that wear proceeds in two distinct stages. The wear occurs by a relatively mild plastic-grooving process in the initial stage, but eventually gives way to a severe grain pull-out process after a defined period of sliding test. The datails of the transition mechanism are presented. The effects of grain size and second phase particle on the wear transition are also presented.

• 한국결정성장학회지
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• 제7권1호
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• pp.108-116
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• 1997

초크랄스키 대류에서의 동적 천이과정에 대한 실험 및 수치해석 연구가 수행되었다. 결정의 회전에 의한 강제대류와 결정/용융 경계면과 도가니 외벽간의 온도차에 의한 자연대류의 상호작용에 의해서 결정되어지는 유동구조와 천이현상을 해석하기 위해 도가니 내의 온도진동 특성을 시간주기($t_p$)와 진동크기($Delta\theta$)에 의해 검토하였다. 혼합대류인자에 따른 천이현상의 체계적인 연구가 수행되었으며($0.134\le Ra/PrRe^2 \le3.804$), 천이현상에 대한 Pr수의 영향을 조사하였다. 천이 메카니즘을 이해하기 위해, 자오면상의 온도장과 중심축에서의 축방향 속도에 대한 해석이 부가되었다.

• 분석과 대안
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• 제7권2호
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• pp.35-77
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• 2023

This study aims to solve the entangled loop between demographic transition (DT) and economic growth by analyzing cross-country data. We undertake a national-level group analysis to verify the compressed transition of demographic variables over time. Assuming that the LA (latecomer advantage) on DT over time exists, we verify that the DT of the latecomer is compressed by providing a formal proof of LA on DT over income. As a DT has the double-kinked functions of income, we check them in multiple aspects: early maturation, leftward threshold, and steeper descent under a contour map and econometric methods. We find that the developing countries (the latecomer) have speedy DT (CDT, compressed DT) as well as speedy income such that DT of the latecomers starts at lower levels of income, lasts for a shorter period, and finishes at the earlier stage of economic development compared to that of developed countries (the early mover). To check the balance of DT, we classify countries into four groups of DT---balanced, slow, unilateral, and rapid transition countries. We identify that the main causes of rapid transition are due to the strong family planning programs of the government. Finally, we check the effect of latecomer's CDT on economic growth inversely: we undertake the simulation of the CDT effect on economic growth and the aging process for the latecomer. A worrying result is that the CDT of the latecomer shows a sharp upturn of the working-age population, followed by a sharp downturn in a short period. Compared to early-mover countries, the latecomer countries cannot buy more time to accommodate the workable population for the period of demographic bonus and prepare their aging societies for demographic onus. Thus, we conclude that CDT is not necessarily advantageous to developing countries. These outcomes of the latecomer's CDT can be re-interpreted as follows. Developing countries need power sources to pump up economic development, such as the following production factors: labor, physical and financial capital, and economic systems. As for labor, the properties of early maturation and leftward thresholds on DTs of the latecomer mean that demographic movement occurs at an unusually early stage of economic development; this is similar to a plane that leaks fuel before or just before take-off, with the result that it no longer flies higher or farther. What is worse, the property of steeper descent represents the falling speed of a plane so that it cannot be sustained at higher levels, and then plummets to all-time lows.

• Asian-Australasian Journal of Animal Sciences
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• 제31권11호
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• pp.1756-1765
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• 2018

Objective: The purpose of this study was to evaluate the influence of body condition score (BCS) at calving on the metabolic status of female Murrah buffaloes in the transition period. Methods: Thirty-seven pregnant buffaloes (multiparous) were selected and monitored during the transition period based on their body condition score and on the estimated calving date. Two groups were formed: i) buffaloes with a BCS>3.5 (n = 17); this group was classified and named 'high BCS at calving' (HBCS); and ii) buffaloes with a $BCS{\leq}3.5$ (n = 20); this group was classified and named 'low BCS at calving' (LBCS). All animals were monitored during the last 30 days of pregnancy and the first 70 days post-calving and kept in the same environment and under the same feeding and management conditions. Mean values for BCS at calving were $2.98{\pm}0.9$ (mean${\pm}$standard error of the mean [SEM]) and $4.21{\pm}0.9$ (mean${\pm}$SEM) for the HBCS and LBCS groups, respectively. Results: The HBCS group showed higher milk fat content (p = 0.007) and milk fat yield (p = 0.027) and a higher concentration of milk urea nitrogen (p = 0.001) than LBCS buffaloes, which in turn had a lower urine pH value (p = 0.033) than HBCS buffaloes in the pre-calving period (7.86 for HBCS vs 7.76 for LBCS). The HBCS animals had a higher concentration of erythrocytes (p = 0.001) and hematocrit (p = 0.012) post-calving and a higher hemoglobin concentration (p = 0.004) pre-calving. Conclusion: Buffaloes during the transition period exhibited some variations in the oxidative stress related to their metabolic status. After calving, buffaloes with a high BCS at calving and greater lipid mobilization have a more marked alteration in oxidative status, but improved production performance.

• 대한가정학회지
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• 제36권5호
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• pp.167-185
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• 1998

The propose of this study was to develop the new pre-parent education program for couples in i=transition to parenthood. This program was consisted three process, total eight sessions. The first process(the basic process) has two sessions. This process was designed to understand the whole parenthood, and to cope the role strain in early parenting period. The second process has three sessions, designed to enrich the marital relationship before the baby was born. And the Third process(parent-child process) has three sessions, too. Especially in last sessions, parent can exercise infant caring, and adapt fetus to their family member.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.923-926
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• 2000

This paper concerned with the patterns of foot-floor contact and electromyography activities of the lower extremity of the body during the termination of human gait. The termination of human gait is defined as the transition from a steady-state gait to a quiet standing posture. The transition between these two states has not been extensively studied and defined. There appears to be a critical period in the gait cycle that the decision to terminate gait or continue to take an additional step must be made.

• 산업공학
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• 제13권4호
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• pp.738-744
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• 2000

This Paper presents a method for unfinished work transition probability distribution of modulated $n^*D/D/l$ queue with overload period. The Modulated $n^*D/D/l$ queue is well known as a performance analysis model of ATM multiplexer with superposition of homogeneous periodic on-off traffic sources. Theory of probability by conditioning and results of $N^*D/D/l$ queue are used for analytic methodology. The results from this paper are expected to be applied to general modulated $n^*D/D/l$ queue.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.323-337
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• 2009

This paper researched the adiabatic characteristic, safety and sound insulation characteristic of rolling stock window pane type and transition process of korean train vehicle window glass, and also including investigating a hereafter course of development. The window pane have provided the romantic feeling and the external scenery of train travel to the passenger in period of korea 110 year railway history. From the adiabatic viewpoint, this paper reviewed heat conductivity(U-value) and solar factor according to window pane type, including the safety and sound transmission loss of window pane.

• 한국수정란이식학회지
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• 제23권4호
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• pp.245-250
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• 2008

This study was designed to investigate the effect of essential amino acids (EAA) and/or non-essential amino acids (NEAA) on the development of parthenogenetic and somatic cell nuclear transfer (SCNT) porcine embryos in vitro. To evaluate the timing of amino acids supplementation, activated oocytes were cultured in NCSU23-PVA with EAA, NEAA or NEAA+EAA (AAs) during specific periods as below: EAA, NEAA or AAs were supplemented during Day 0 to 6 (whole culture period: ALL), Day 2 to Day 6 (post-maternal embryonic transition period: POST-MET), Day 5 to Day 6 (post-compaction period: POST-CMP), Day 0 to Day 2 (pre-maternal embryonic transition period: PRE-MET), or Day 0 to Day 4 (post-compaction period: PRE-CMP). Supplementation of NEAA decreased cleavage rates in PRE-MET and PRE-CMP and also decreased blastocyst rates in POST-CMP. On the other hand, EAA significantly enhanced blastocyst formation rate in POST-MET and no detrimental effect on embryonic development in other groups. Interestingly, NEAA and EAA had synergistic effect when they were supplemented to the medium during whole culture period. Supplementation of AAs also enhanced SCNT porcine embryo development whereas BSA-free medium without AAs could not supported blastocyst formation of SCNT embryos. In conclusion, existence of EAA and NEAA in defined culture medium variously influences the development of parthenogenetic and SCNT porcine embryos, and their positive effect are only occurred when both EAA and NEAA are supplemented to the medium during whole culture period. Additionally, AAs supplementation enhances the blastocyst formation of SCNT porcine embryos when they are cultured in the defined condition.

• Clinical and Experimental Pediatrics
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• 제50권3호
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• pp.230-235
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• 2007

In the early neonatal period, the neonate is challenged by the loss of the placental calcium transport and manifests a quick transition, from an environment in which PTHrP plays an important role to a PTH- and 1,25-dihydroxyvitamin D-controlled neonatal milieu. Disturbances in mineral homeostasis are common in the neonatal period, especially in premature infants and infants who are hospitalized in an intensive care unit. In many cases these disturbances are thought to be exaggerated responses to the normal physiological transition from the intrauterine environment to neonatal independence. Some disturbances in calcium and phosphate homeostasis are the result of genetic defects, which in many instances can now be identified at the molecular level. Although fetus develop remarkably normally in the presence of maternal calcium, PTH and vitamin D deficiency, the neonates demonstrate abnormalities that are consequences of the prior abnormal maternal calcium homeostasis. Evaluation and management of hypocalcemia and hypercalcemia in neonate requires specific knowledge of perinatal mineral physiology and the unique clinical and biochemical features of newborn mineral metabolism.