• Preventive Nutrition and Food Science
• /
• v.8 no.3
• /
• pp.253-259
• /
• 2003

Conjugated linoleic acid (CLA) is a class of positional, geometric conjugated dienoic isomers of linoleic acid (LA). CLA activates the immune system, protects against tumorigenesis, and reduces the incidence of atherosclerosis. Trans-10, cis-12 CLA has specific effects on lipid metabolism, it has been shown to reduce body fat gain and regulates some adipocyte secreted proteins in vivo and in vitro. Here we report that a CLA mixture affects cytokine secretion from rat primary adipocytes. Rat primary adipocytes were treated with 1 mM, 100 $\mu$M, 1 $\mu$M or 100 nM CLA mixture doses; and leptin, tumor necrosis factor alpha (TNF a ), interleukin-6 (IL-6) and glycerol levels in the medium were measured. Leptin secretion was lower, TNF $\alpha$ secretion higher and IL-6 secretion did not change in response to the CLA mixture. Leptin and TNF $\alpha$ secretions did not change with CLA mixture treatment in a dose-dependent manner. In addition, the CLA mixture did not appear to enhance lipolysis in rat primary adipocytes. In conclusion, our study demonstrates that the decrease in leptin and increase in TNF $\alpha$ secretion in adipocytes treated with CLA mixture may be due to the apoptotic effect and to a reduction in peroxisome proliferator-activated receptor gamma (PPAR ${\gamma}$ ) ligands.

• Journal of Drive and Control
• /
• v.16 no.4
• /
• pp.23-31
• /
• 2019

The purpose of this study was to evaluate the PTO severeness for an agricultural tractor during disk plow and rotary tillage. The PTO load measurement system was constructed with data acquisition and a PTO torquemeter. Field experiments were conducted at a combination of traveling speed (L3 Low, L3 High) and PTO speed (P1, P2). The load spectrum was generated using the rain-flow counting method, and the SWT method was used to consider the range and mean of the PTO load. The damage sum was calculated by applying a modified miner rule, which is a cumulative damage law. The relative severeness was expressed as the ratio of the lowest damage sum. Relative severeness was higher with the lower PTO gear stage, and higher driving gear stage and it was approximately 40-102 times higher for rotary tillage than disk plow tillage in the same gear stages. The relative severeness was 1010.12 in the rotary tillage under L3 High P1 based on the disk plow tillage under L3 Low P2.

• Journal of Preventive Medicine and Public Health
• /
• v.7 no.1
• /
• pp.131-138
• /
• 1974

The author has conducted survey on the status of physical growth and morbidity of the children for christian children's fund programme, as a means of collecting basic data for the anticipated establishment of a health planning. A total 345 children aged 9 to 16 underwent C.C.F. programme while as a control, a total of 480 children of same ages from the middle-class school children in Jeonju area was also studied. As results of survey conducted for a period of one month (form July 1 to 31, 1974) on a total 429 children in 347 households living in Jeonju area. I. Socio-economic background 1. By educational status of the children, 39.9 per cent of the total children was attending at primary school, 33.8 per cent in middle school and 15.6 per cent in high school. 2. The greatest proportion or 28.8 per cent of the household head were engaged in labor, 17.9 per cent in peddler and 13.2 per cent in retail. 3. As for the living standard of the households, low class constitued 90.1 per cent, middle and high classes only 9.9 per cent. 4. 39.5 per cent of the households had their own house, 39.1 per cent lived in rent deposit house or rooms and 14.6 per cent in monthly rented house and rooms. II. Physical growth and nutritional status 1. The growth of children for C.C.F. programme in terms of height was found to be slightly smaller than the school children. The ages frm 9 to 16 corespond to the 'secondary growth and replenishment period and this period was regarded to be the one most affected by environmental and nutritional factors of all the other periods of growth and developmet. 2. The body weight of the children for C.C.F. presented a quite different pattern from that of the school children. The above findings appeared thin-and-long stature from the famillies with higher living standard while those from the household with low standard of living had a short-and-plump one. 3. According to the values of Rohrer's index, the children of C.C.F carried a higher degree of 'replenishment' than the children in Jeonju area and adolesecence comes later for the girls under C.C.F. programme. III. Morbidity 1. The monthly prevalence rate was 110.0 per thousand persons for the children under C.C.F. programme. 2. The total number of case was classified by timing of the incidence as follws. 40.0 per cent was constituted by diseases carried over from tile previous month and 60.0 per cent by new incidences. 3. The diseases were broken down by W.H.O. disease classification into the greatest proportion or 39.1 per thousand person constituted by disease of the digestive system.

• Transactions of the Korean hydrogen and new energy society
• /
• v.14 no.3
• /
• pp.229-235
• /
• 2003

A 50W class MCFC stack was operated in order to test a new design of the circular shaped separator. in the new design, the anode gas was supplied into the stack and was exhausted out of the stack after the anode reaction. The exhausted gas was reacted with the cathode gas supplied with excess oxygen in the vessel in which the stack was placed. Then the reacted gas flowed into the cathode side of the stack and was exhausted through the outlet located in the center of the stack. The average voltage of the single cells in the stack was 0.835V under the current density of $150mA/cm^2$, initially, and the degradation rate of the stack voltage was 1.7%/1,000h. High stack voltage with good stability of the present stack was due to the small temperature gradient in the stack. The small temperature gradient as well as the easiness of temperature control was the result of the new configuration of the separator which utilized the heat of the combustion reaction between anode outlet gas and the cathode inlet gas for heating the stack.

• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.6
• /
• pp.757-764
• /
• 2011

In this study, we analysed the influence of the performance and inflow flow of a radial inflow turbine with the variation of vane nozzle exit angles for a 100kW class turbine applicable in the waste heat recovery system. For this, three-dimensional CFD analysis was performed using commercial code called ANSYS Fluent 12.1. As the vane nozzle exit angle was more increased the reattachment region near blades of the vane nozzle got smaller, and also the Mach number at vane nozzle exit was observed to be 1 due to the effect of the cross section reduction. Through this study, we expect that the analysed results will be used as the design material for the composition of the turbine optimal design parameters corresponding to the target output power.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.06a
• /
• pp.17-20
• /
• 2006

한국에너지기술연구원에서는 가정용 고분자연료전지 열병합 발전시스템을 위한 통합형 천연가스 연료처리 시스템을 개발해 왔다. 가정용 시스템으로서 필수적인 소형화와 고효율을 현실화하기 위해, 연료처리 시스템의 각 단위 공정 즉 수증기 개질, 수성가스 전이, 선택적 산화 공정 등을 이중 동 심관형 반응기에 통합하여 상호 열교환이 용이하도록 반응기를 설계하였다. 현재 시험 운전 중인 Prototype-I 연료 처리 시스템은 1kW급 고분자 연료전지 열병합 발전 시스템에 개질 가스를 공급하기 위해 설계되었으며, 기초 성능은 정격 부하 운전시 열효율 78% (HHV 기준), 메탄 전환율 91%이다. 개질 가스 내 일산화탄소 농도는 고분자 연료전지 전극의 피독을 피하기 위해 10ppm 이하로 유지되어야 하며, Prototype-I 연료 처리 시스템은 백금과 루테늄 촉매를 적용한 선택적 산화 반응기를 통해 개질 가스 내 일산화탄소 농도를 10ppm 이하로 제거하였다. 일반 가정에서는 고분자 연료전지 시스템의 부하 변동이 예상되기 때문에 연료 처리 시스템의 부하 변동 운전 특성도 살펴보았다 정격 부하에서 80%, 60%, 40%로 부하를 변동하며 운전하였고, 각 부하에서 안정한 메탄 전환율과 10ppm이하의 일산화탄소 농도를 보였다. 80%까지는 열효율이 77%로 큰 변화를 보이지 않았으며, 60%에서는 76%, 40%에서는 72%로 열효율이 감소하는 현상을 보였다 연료 처리 시스템의 일일 시동-정지 운전시 내구성을 테스트 중이다. 현재까지 50여회의 일일-시동 정지를 시도하였다 시동 후 약 세 시간가량의 정력 부하 운전을 실시한 후 부하 변동을 실시하였고, 총 운전 시간 8시간 정도 운전한 후 시스템을 정지하였다 메탄 전환율과 일산화 탄소 농도, 열효율을 모니터링 하고 있으며, 현재까지 초기 성능을 그대로 유지하고 있다. 앞으로 일일시동-정지 운전 시험을 지속하면서 초기 시동 특성 및 부하 변동에 따른 응답 특성 개선, 그리고 연료전지와의 연계 운전을 실시할 예정이다

• The Journal of the Korea institute of electronic communication sciences
• /
• v.15 no.3
• /
• pp.421-432
• /
• 2020

This paper proposes a 2-kW solid-state power amplifier (SSPA) developed by employing power amplifier pallets designed using gallium-nitride high electron mobility transistors, which is used in S-band military radars and to replace existing traveling-wave tube amplifier (TWTA). The SSPA consists of a high-power amplifier module, which combines eight power amplifier pallets, a drive amplifier module, a digital control module, and a power supply unit. First, the amplifier module and component were integrated into a small package to account for space limitations; next, an on-board harmonic filter was fabricated to reject spurious components; and finally, an auto gain control system was designed for various duty ratios because recent military radar systems are all active phase radars using the pulse operation mode. The developed SSPA exhibited a max gain of 48 dB and an output power ranging between 63-63.6 dBm at a frequency band of 3.1 to 3.5 GHz. The auto gain control function showed that the output power is regulated around 63 dBm despite the fluctuation of the input power from 15-20 dBm. Finally, reliability of the developed system was verified through a temperature environment test for nine hours at high (55 ℃) / low (-40℃) temperature profile in accordance with military standard 810. The developed SSPA show better performance such as light weight, high output, high gain, various safety function, low repair cost and short repair time than existing TWTA.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.2 no.1
• /
• pp.21-30
• /
• 1997

The present study reports the density, growth and production of a razor clam, Sinollovacula constricta, which is known to be one of the important fishreies catches from the Korean tidal flat. The annual yield reached to about 6,000 metric tons per year till 1994. The study was conducted on the Hwaseong tidal flat located on the central west coast, 40 kilometers south-west from Seoul. The annual yield of the razor clam in this area reached to about 50% of the total catch from the whole Korean coast. Samples were colleted monthly at 14 occasions from May 1992 to August 1993. Density of S. constricta ranged from 92~165 individuals per square meter during the study period. General trend of decreasing density was observed when the animal became older, but an exception was the year class of 1991 whose density was lower than that of 1990. The size of the shell was clearly separated into two classes during fall and winter (from September to February), however, the maximum frequency of the length of small size classes moved to right after February. It indicates a fast growth of young clams from spring to summer. Fast growth of the shell could also be examined by the growth curve. The shell growth of the whole life span was described by the von Bertalanffy equation of $L_t=89.3{\times}[1{\exp}\{-0.58{\times}(t+0.73\}]$. The growth in flesh dry weight was well fitted to the Gompertz growth model with the equation, $W_t=5.00{\times}{\exp}\{-4.31{\times}{\exp}(-0.043{\times}t)\}$. The clam lost about 30% of the body weight during spawning in August. The annual production calculated based on the data from September 1992 to August 1993 amounted to 150 g $DW{\cdot}m^{-2}{\cdot}yr^{-1}$ which was 2~50 fold higher than those of other bivalves occurred in Korea. This estimate was patitioned by each year classes; 87.5 by 1992, 53.4 by 1991, 59.0 by 1990 and -30.0 g $DW{\cdot}m^{-2}{\cdot}yr^{-1}$ by 1989 year class.

• Asian-Australasian Journal of Animal Sciences
• /
• v.26 no.8
• /
• pp.1065-1071
• /
• 2013

The swine leukocyte antigen class II molecules are possibly associated with the induction of protective immunity. The study described here was to investigate the relationship between polymorphisms in exon 2 of the swine DQA gene and piglet diarrhea. This study was carried out on 425 suckling piglets from three purebred pig strains (Large White, Landrace and Duroc). The genetic diversity of exon 2 in swine DQA was detected by PCR-SSCP and sequencing analysis, eight unique SSCP patterns (AB, BB, BC, CC, CD, BD, BE and DD) representing five specific allele (A to E) sequences were detected. Sequence analysis revealed 21 nucleotide variable sites and resulting in 12 amino acid substitutions in the populations. A moderate level polymorphism and significant deviations from Hardy-Weinberg equilibrium of the genotypes distribution were observed in the populations (p<0.01). The association analysis indicated that there was a statistically significant difference in the score of piglet diarrhea between different genotypes, individuals with genotype CC showed a lower diarrhea score than genotypes AB ($0.98{\pm}0.09$), BB ($0.85{\pm}0.77$) and BC ($1.25{\pm}0.23$) (p<0.05), and significantly low than genotype BE ($1.19{\pm}0.19$) (p<0.01), CC genotype may be a most resistance genotype for piglet diarrhea.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.50 no.4
• /
• pp.511-519
• /
• 2014

This study is aimed to analyze the three-dimensional underwater irradiance using an optical simulation software and to clarify the propriety and operation method under considering luminous intensity distribution of the luring lamp and penetrability in the seawater, when we use the light diffuser type 300W high powered LED and the metal halide lamp (MHL) on a coastal squid jigging vessel in the 10-ton class, simultaneously. For their attenuation characteristics of each wavelength in relation to the sea, LED lamp was to be effective in the 1.9-fold at 50 m depth and 2.1-fold at 80 m for underwater irradiance more than MHL according to the power consumption. In addition, the underwater irradiance distribution using the LED and MHL combination was rather increased even when reducing total power usage up to 20% depending on the simulation with changing the configuration and lighting angle of the lamp. These results can be utilized as an evaluation method of the operation and performance of the LED lamp according to adjusting its arrangement and lighting angle.