• Preventive Nutrition and Food Science
• /
• 제1권2호
• /
• pp.234-238
• /
• 1996

The purpose of this study was to determine whether vitamin {TEX}$B_{6}${/TEX} deficiency and age affect the blood cho-lesterol profile in exercising rats. Fifty four rats were fed either a viramin {TEX}$B_{6}${/TEX} deficient dief(-{TEX}$B_{6}${/TEX}) of a control diet(+{TEX}$B_{6}${/TEX}) for 6 weeks, then subdivided into 3 groups:non-exercise group(NE), exercise and sacrifice group(ES), exercise and recuperation group(ER). ES group was exercised in treadmill({TEX}$10^{o}${/TEX}, 0.5~0.8km/h) for 2 hours and sacrifice. ER group was recuperated three days with respective diet after exercise. At week 3 and 6, and level of plasma total cholesterol(TC), high density lipoprotein cholesterol(HDL_C) and low density lipoprotein cholesterol(LDL_C) were compared. In NE group, there was no difference in the levels of TC, HDL_C and LDL_C between +{TEX}$B_{6}${/TEX} rats and -{TEX}$B_{6}${/TEX} rats. The plasma levels of TC and LDL_C of 6 weeks were higher than those of 3 weeks and on difference in HDL_V between 3 weeks rats and 6 weeks rats. In ES group, there was also no difference in the levels of TC, HDL_C and LDL_C between +{TEX}$B_{6}${/TEX} rats and -{TEX}$B_{6}${/TEX} rats and there was no difference in TC, LDL-cholesterol between 3 weeks rats and 6 weeks rats. The level of HDL_C pf 6 weeks was lower than that of 3 weeks rats. In ER group, there was no difference in the levels of TC and LDL_C not only between +{TEX}$B_{6}${/TEX} rats and-{TEX}$B_{6}${/TEX} rats but also between 3 weeks rats and 6 weeks rats. The level of HDL_C was lower in -{TEX}$B_{6}${/TEX} rats than in +{TEX}$B_{6}${/TEX} rats and higher in 6 weeks rats than in 3 weeks rats. These results suggest that vitamin {TEX}$B_{6}${/TEX} deficiency may affect the HDL_C during exercise and after recuperation. The desirable effect of exercise on plasma Cholesterol profile is strengthened in adult age than young age.

• Preventive Nutrition and Food Science
• /
• 제2권3호
• /
• pp.214-218
• /
• 1997

The purpose of this study was to investigate the potential hypolipidemic effect of job's tears diet with the controlled intake of fiber in streptozotocin induced diabetic rats. Forty eight rats were fed either control diet or experimental diets (Raw, milled job's tears(RMJ); Raw, whole grain job's tears(RWJ);Steamed, milled job's tears(SMJ);Roasted, milled job's tears(OMJ)) for 3 weeks. The levels of total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), free fatty acid(FFA) and triglyceride (TG) in plasma, liver and skeletal muscle were compared. Compared to diabetic control group, the level of plasma TC was lower in OMJ an SMJ fed rats, and was not different from that in RMJ and RWJ fed rats. The level of LDL-C was significantly lower in RMJ, OMJ and SMJ fed rats. For plasma HDL-C levels, no difference was observed among all group. Plasma FFA level significantly lower in RMJ, SMJ and RWJ fed rats, Plasma TG a levels of all job's ears fed groups were 50∼70% lower and liver TG levels of all job's tears fed groups were 70∼80% lower than those fo diabetic control group. For muscle TG, no differences were seen among all groups. These results suggest that steamed job's tears and roasted job's tears could have the potentaila on improving lipid profile fo diabetes in clinical setting and the different cooking methods of job's tears might affect the lipid profile of the diabetic rats.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2000년도 춘계학술발표대회
• /
• pp.600-603
• /
• 2000

DNA chip containing 207 E. coli genes related to important metabolisms such as (TCA cycle, glycolysis, fermentation and etc) were used to carry out a comprehensive investigation of the change in metabolism and physiology during high cell density culture of E. coli by fed-batch cultivation.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 2004년도 한국우주과학회보 제13권1호
• /
• pp.35-35
• /
• 2004

Inhomogeneity Is important in wave coupling and mode conversion. We numerically examine the conversion of extraordinary(X) waves into upper hybrid(UH) waves in inhomogeneous plasmas by using a three-dimensional multi-fluid numerical model. A one-dimensional Inhomogeneous density profile is assumed in a cold and collisionless plasma. The density gradient is taken to be perpendicular to the magnetic field. An impulsive input is assumed to excite the X waves in the inhomogeneous box model. (omitted)

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1999년도 전력전자학술대회 논문집
• /
• pp.577-580
• /
• 1999

High power density on-board power supply is implemented by using flat transformer. In the high frequency switching converters, large leakage inductance increases the switching stress and duty cycle loss, which sometimes limits maximum switching frequency. The flat transformer is designed by using special core structure, which has very low profile and low temperature rise since the thermal loading is spread evenly over a larger area. 100W, 3.3V output on board supply is built and tested and 50.7W/$\textrm{inch}^{3}$ power density is achieved.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2005년도 추계학술대회논문집
• /
• pp.314-317
• /
• 2005

There are many benefits such as increased areal density, reduced power consumption, applied smaller size and improved shock resistance in Load/Unload(L/UL) mechanism. It has been the key technology of developing small form factor hard disk drive used in portable digital devices. The main objectives of L/UL are no slider-disk contact and faster L/UL process. For realizing those, we must consider many design parameters in L/UL systems. In this paper, we focus on the effects of ramp profile. We can investigate dynamic characteristics of suspension tap and slider on ramp during unloading process experimentally. In special, we examine the effects of vortical velocities, ramp slopes and disk vibrations. As the result of these experiments, we propose design criteria of advanced ramp profile for good unloading performance.

• 공업화학
• /
• 제19권2호
• /
• pp.228-235
• /
• 2008

니켈 표면처리 공정에서 전류밀도에 따라 니켈의 전착두께가 증가되었으며, 증가폭은 $6{\sim}10A/dm^2$에서 저전류보다 높게 나타났다. 전류밀도를 측정하기 위해 Hull-cell 분석을 수행 하였다. 최적 공정온도는 $60^{\circ}C$, pH는 3.5~4.0이었고, 전해용액 중 니켈이온의 농도는 300 g/L 이상에서 농도에 따라 전착두께가 증가되었다. 전류밀도에 따라 용액 중 니켈이온 감소 속도가 증가되었는데, 이는 음극표면에서 니켈 전착 량에 따른 전착두께의 증가를 나타낸다. 그러나 전착속도가 빠를 경우 니켈 전착 층의 치밀성은 저하되며, 표면의 상태는 불규칙하게 변화된다. 니켈이온의 전착과정이 불규칙하게 일어나 조직의 pin hole 등을 야기해 표면특성을 저하시키는 것으로 확인되었다. 광택니켈 전착 후 25 h 내식을 유지한 결과, 낮은 전류밀도를 유지하는 것이 내식특성이 우수한 것으로 나타났다. 프로그램모사 결과, 전류밀도가 높아질수록 확산 층의 두께는 증가하며, 음극표면의 농도는 낮아진다. 농도분포는 낮은 전류밀도에서 고른 분포를 나타내었으며 이는 일정한 전착두께를 예측할 수 있다. 생산성 저하를 예방하기 위해 공정시간은 크게 변화시키지 않았으며, 전류밀도와 전착두께를 변화시키면서 공정변수를 조절하였다. 본 연구의 표면분석 결과 조직특성이나 내식성 등의 표면 물성이 낮은 전류밀도를 사용할 경우에 더욱 우수한 것으로 나타났다.

• Journal of the Korean Wood Science and Technology
• /
• 제30권1호
• /
• pp.25-33
• /
• 2002

파티클보드의 두께방향으로 밀도경사와 흡음성 개선을 위한 새로운 열압방식개발을 위하여 본 과제를 수행하였다. 적용한 열압방식으로는 기존의 평판가열식 열압방식(A-type pressing), 성형장치내 열압방식(B-type pressing), 그리고 성형장치내 요철카울을 설치한 열압방식(C-type pressing)을 적용하였다. 원료목질은 낙엽송 세이빙을 사용하였으며, 접착제로는 수용성 페놀-포름알데하이드 접착제를 사용하였다. 흡음성 개선을 위한 보드는 열압시 요철카울에 의하여 보드 이면에 계단형 공극을 생성하였다. 열압방식별 제조된 보드의 물리적 및 기계적 성질을 측정하였는 바, 성형장치내 열압을 함으로써 강도적 성능을 향상시킬 수 있는 것으로 나타났으며, 보드의 두께방향 밀도경사 역시 평균밀도에 대한 최소밀도의 비율이 90% 이상을 나타내어 기존의 평판가열식으로 제조한 보드 보다 크게 개선시킬 수 있는 것으로 나타났다. 또한 열압시 요철카울에 의하여 천공을 해 줌으로써 파티클보드의 흡음계수를 향상시킬 수 있는 것으로 나타남으로써 향후 저밀도 후판보드 제조가능성과 흡음재 등 새로운 건축내장재료로의 사용가능성을 확인하였다.

• 한국결정성장학회지
• /
• 제9권6호
• /
• pp.535-541
• /
• 1999

Low-dislocation-density large-diameter GaAs single crystals with low-residual-strain have been strongly required. We have developed dislocation-free 3-inch Si doped GaAs crystals for photonic devices, and low-dislocation-density low-residual-strain 4-inch to 6-inch semi-insulating GaAs crystals for electronic devices by Vertical Bridgman(VB) technique. We confirmed that VB substrates with low-residual-strain have higher resistance against slip-line generation during MBE process. VB-GaAs single crystals show uniform radial profile of resistivity reflecting to the flat solid-liquid interface during the crystal growth. Uniformity of micro-resistivity of VB-GaAs substrate is much better than of the LEC-GaAs substrate, which is due to the low-dislocation-density of VB-GaAs single crystals.

• 동력기계공학회지
• /
• 제21권1호
• /
• pp.43-49
• /
• 2017

This work aims to investigate on the low cycle fatigue life assessment, which is adopted on the strain-life relationship, or better known as the Coffin-Manson relationship, and also the strain energy density-based model. The low cycle fatigue test results of Alloy 617 weldments under $900^{\circ}C$ have been statistically estimated through the Coffin-Manson relationship according to the provided strain profile. In addition, the strain energy density-based model is proposed to represent the energy dissipated per cycle as fatigue damage parameter. Based on the results, Alloy 617 weldments followed the Coffin-Manson relationship and strain energy density-based model well, and they were compatible with the experimental data. The predicted lives based on these two proposed models were examined with the experimental data to select a proper life prediction parameter.