• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 추계학술대회 논문집 전문대학교육위원 P
• /
• pp.13-15
• /
• 1999

The zero voltage and zero current switching(ZVZCS) full bridge (FB) PWM converter using secondary active clamp is characterized by high efficiency, good ZVZCS characteristic, simple topology and low cost. But at the period for discharge of the secondary clamp capacitor, peak pulses and ringing pulse occur in rectified secondary side of the converter. In this paper, a novel secondary active clamp circuit for the ZVZCS FB PWM converter is proposed and a 50 kHz, 500 W prototype converter was experimented for verification of the converter characteristics. It was verified that high voltage peak pulses and ringing pulse on secondary rectified waveforms of the converter are decreased effectively.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.769-772
• /
• 2006

The effects of high temperature on strength, elastic modulus and strain at peak stress of concrete were experimentally investigated. The type of test was the stressed test that a preload was applied to the specimen prior to heating and the load was sustained during the heating period. In this study, the level of preload was 25% of compressive strength at room temperature. All tests were conducted at various temperatures(20,100, 200, 300, 400, 500, 600 and $700^{\circ}C$) for concretes made with W/B ratios 46% and 32%. Test results showed that on the whole, the relative values of strength and elastic modulus, and the real strain value at peak stress were not influenced by the W/B ratio.

• Journal of Chest Surgery
• /
• 제14권1호
• /
• pp.1-8
• /
• 1981

Alterations in serum enzymes were studied in twenty-five patients who underwent open heart surgery in N.M.C. during the period from June 1979, to Feb. 1980. There were fifteen congenital and ten acquired heart diseases. In all patients, Rygg-Kyvsgaard five head roller pump and Polystan bubble oxygenator were used and serial determination of total level of Creatine phosphokinase [CPK], Lactic dehydrogenase [LDH], Glutamic oxaloacetic transaminase [SGOT] were made preoperatively, operation day [just after aortic clamp release, 2 hrs later, 4 hrs later, 6 hrs later], and postoperative days up to 5th day. Immediate postoperative clinical courses were also evaluated. Twenty-five patients were divided into two groups: Group A[13] was cardiopulmonary bypass time more than 95 minutes and aortic clamp time more than 45 minutes. Group B[12] was cardiopulmonary bypass time less than 95 minutes and aortic clamp time less than 45 minutes. The peak levels of SGOT, LDH in Group A were more significantly elevated than Group B [P<0.05]. But peak levels of CPK were not significant between two groups. In the view of clinical evaluation, poor clinical courses were more frequent in Group A [54%] than Group B[8%].

• Journal of Welding and Joining
• /
• 제15권5호
• /
• pp.84-91
• /
• 1997

The metal transfer phenomenon of the pulsed-GMAW is simulated by formulating the electromagnetic force incorporated with the Volume of Fluid algorithm. The free surface profiles, pressure and velocity distributions within the drop are computed numerically. Axial velocity and acceleration generated during peak current period are found to have a significant effect on drop detachment. Therefore, the accelerated inertia force becomes one of important factors affecting metal transfer in the pulsed-GMAW. When the pulse current parameters are selected properly, the molten drop is detached just after current pulse, and the operating range of the pulsing frequency increases with higher peak current and duty cycle. Calculated operating ranges show reasonably good agreements with the available experimental data.

• Nuclear Engineering and Technology
• /
• 제38권2호
• /
• pp.195-200
• /
• 2006

In order to confirm the integrity of IRWST following a severe accident, the hydrogen behavior inside and around the IRWST has been investigated for an SBO accident. A detailed containment model, including 18 control volumes for IRWST, has been developed. Analysis results show that the peak hydrogen concentration is about 57% during the core melting period. The combustion regime shows that flame acceleration and DDT are possible in the IRWST. The flame acceleration criterion is met when the peak hydrogen concentration occurs; the 7 -DDT criterion is also met during some periods. These results show certain measures may be required to assure IRWST integrity against an SBO accident.

• 천문학회보
• /
• 제38권2호
• /
• pp.92.2-92.2
• /
• 2013

We revisit the 1.3-year (yr) signals observed on the Sun, in the interplanetary space, and in the Earth's magnetosphere to study the coupling among signals from the three regions for about forty years (1970--2007) covering three solar cycles 21, 22, and 23. For this, we make dynamic spectra of datasets including three different regions. From this, we estimate the peak frequency around 1.3 yr for each region and the corresponding band power. We found that coherent power only appears during 1987-1995 and the coherent behavior is found only in the interplanetary space and Earth, not in the Sun. Although the solar surface magnetic field shows significant power around 1.3 yr, their peak frequencies are statistically different from those of the outer regions, which make us to dismiss the existence of coherence among the three regions. But it is notable that the peaks in band power corresponding to the 1.3-yr period are clearly simultaneous in the interplanetary space and Earth.

• Journal of Chest Surgery
• /
• 제21권2호
• /
• pp.231-239
• /
• 1988

Currently numerous methods are in use for myocardial hypothermia as a myocardial preservation modality for cardiac operation. During cardiac ischemia after crystalloid cardioplegia[4C GIK solution], topical cold saline[Group I, a=9], topical ice slush[Group II, n=9] and topical ice chip[Group III, a=10] have been compared for myocardial surface cooling in the isolated rat heart model of cardiopulmonary bypass. During postischemic period, hemodynamic functions[aortic flow, coronary flow, peak aortic pressure and heart rate], biochemical enzymatic activities and cellular injuries with electron microscope were evaluated in this isolated rat heart perfusion model. Postischemic aortic flow, cardiac output and peak aortic pressure in Group I and Group II recovered better than Group III.[p< 0.05] Postischemic creatine kinase and lactate dehydrogenase leakages in Group II and Group III increased more than Group l and postischemic mitochondrial swelling in Group III was more severe than Group I, and Group II.[p< 0.05] These results suggest that topical cold saline was the better method than topical ice slush or topical ice chip as a myocardial preservation modality in the isolated rat heart model of cardiopulmonary bypass.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
• /
• pp.290-292
• /
• 2008

we applied Wind Field Module of PHRLM so that disaster prevention agency concerned can effectively estimate the possible strong wind damages by typhoon. In this study, therefore, we estimated wind speed at 300m level using 700hPa wind according to the research method by Franklin(2003), PHRLM(2003), and Vickery and Skerlj(2005). Then we calculated wind speed at 10m level using the estimated wind speed at 300m level, and finally, peak 3.second gust on surface. The case period is from 18LST August 31 to 03LST September 1, 2002, when the typhoon Rusa in 2002 was the most intense. Among disaster prediction models in the US, Wind Field Module of PHRLM in Florida was used for the 2002 typhoon Rusa case. As a result, peak 3.second gust on the surface increased $10\sim20%$ in the typhoon's 700hPa wind speed.

• Animal Bioscience
• /
• 제35권10호
• /
• pp.1499-1511
• /
• 2022

Objective: This study was aimed to estimate the genetic parameters, including genetic and phenotypic correlations, of milk yield, lactation curve traits and milk composition of Thai dairy cattle from three government research farms. Methods: The data of 25,789 test-day milk yield and milk composition records of 1,468 cattle from lactation 1 to 3 of Holstein Friesian (HF) and crossbred HF dairy cattle calved between 1990 and 2015 from three government research farms in Thailand were analysed. 305-day milk yield was estimated by the Wood model and a test interval method. The Wood model was used for estimating cumulative 305-day milk yield, peak milk yield, days to peak milk yield and persistency. Genetic parameters were estimated using linear mixed models with herd, breed group, year and season of calving as fixed effects, and animals linked to a pedigree as random effects, together with a residual error. Univariate models were used to estimate variance components, heritability, estimated breeding values (EBVs) and repeatability of each trait, while pairwise bivariate models were used to estimate covariance components and correlations between traits in the same lactation and in the same trait across lactations. Results: The heritability of 305-day milk yield, peak milk yield and protein percentage have moderate to high estimates ranging from 0.19 to 0.45 while days to peak milk yield, persistency and fat percentage have low heritability ranging from 0.08 to 0.14 in lactation 1 cows. Further, heritability of most traits considered was higher in lactation 1 compared with lactations 2 and 3. For cows in lactation 1, high genetic correlations were found between 305-day milk yield and peak milk yield (0.86±0.07) and days to peak milk yield and persistency (0.99±0.02) while estimates of genetic correlations between the remaining traits were imprecise due to the high standard errors. The genetic correlations within the traits across lactation were high. There was no consistent trend of EBVs for most traits in the first lactation over the study period. Conclusion: Both the Wood model and test interval method can be used for milk yield estimates in these herds. However, the Wood model has advantages over the test interval method as it can be fitted using fewer test-day records and the estimated model parameters can be used to derive estimates of other lactation curve parameters. Milk yield, peak milk yield and protein percentage can be improved by a selection and mating program while days to peak milk yield, persistency and fat percentage can be improved by including into a selection index.

• 아시안잔디학회지
• /
• 제22권1호
• /
• pp.35-48
• /
• 2008

골프장 잔디의 주요 해충의 하나인 등얼룩풍뎅이의 발생상창을 알아보기 위하여 부산과 군포, 김포 지역의 골프장에서 토양 내에서의 발육경과와 페로몬트랩을 이용한 성충의 발생경과를 2004년부터 2007년까지 조사하였다. 등얼룩풍뎅이 성충의 발생은 6월 초순에서 8월 하순까지였는데, 성충의 발생 peak는 조사지역과 년도에 따라 차이가 있었다. 부산지역에서는 2006년 6월 25일에 발생 peak를 보였고, 2007년에는 6월 22일에 발생 peak를 보였는데 군포지역에서는 각각 6월 30일과 29일에 peak를 보였다. 페로몬트랩에 유인된 등 얼룩풍뎅이의 개체수는 조사 골프장별로 차이를 보였다. 등얼룩풍뎅이 유충의 발육경과도 부산지역이 군포지역에 비하여 빨랐는데 군포에서는 2004년 8월 27일 조사에서 2령충만 발견된데 비하여 부산지역에서는 같은 해 8월 26일에 조사한 것에서 2령충과 3령충이 함께 발견되었다. 부산지역에서 등얼룩풍뎅이의 발생경과는 월동한 3령 유충이 5월 초순에서 6월 중순까지 용화하였고, 6월 초순부터 우화하였다. 그리고 6월 하순부터 부화하였다. 8월 중순부터는 3령충이 되어 월동에 들어갔다. 등얼룩풍뎅이 성충의 교미 peak 시간은 20:00부터 22:00였다.