• 설비공학논문집
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• 제11권6호
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• pp.846-854
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• 1999

Measurements of the local heat transfer coefficients were made on a hemispherically convex surface with a round oblique impinging jet. The liquid crystal transient method was used for these measurements. This method, which is a variation on the transient method, suddenly exposes a preheated wall to an impinging jet while video recording the response of liquid crystal for the surface temperature measurements. The Reynolds number used was 23000 and the nozzle-to-surface distance was L/d=2, 4, 6, 8, and 10 and the jet angle was $\alpha$=$0^{\circ}\; 15^{\circ}\;30^{\circ}C\; and \;40^{\circ}C$. In the experiment, the Nusselt number at the stagnation point decreases as the jet angle increases and has the maximum value for L/d=6. The X-axis Nusselt number distributions exhibit Secondary maxima at $0^{\circ}C\re $\alpha$\re 15^{\circ}C, L/d\le6$ for X/d＜0(upstream) and at $0^{\circ}C\re $\alpha$40^{\circ}C,\;L/d\le4\;and\; at\; 30^{\circ}C\re $\alpha$$\leq$40^{\circ}C,\;L/d\le 6 $for X/d＞0(downstream). The secondary maxima occurs at long distance from the stagnation point as the jet angle increases or the nozzle-to-surface distance decreases. The Y-axis Nusselt number distributions exhibit secondary maxima at Y/d=$\pm$2 for $0^{\circ}C\le a\le30^{\circ}C\; and\; L/d\le4, and \;for\;$\alpha$=40^{\circ}C$and L/d=2. The displacement of the maximum Nusselt number from the stagnation point increases as the jet angle increases or the nozzle-to-surface distance decreases and the maximum distance is about 0.67 times of the nozzle diameter. The ratio of the maximum Nusselt number to the stagnation Nusselt number increases as the jet angle increases.

• 한국화재소방학회논문지
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• 제30권1호
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• pp.24-30
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• 2016

자연발화 특성은 가연성물질의 취급 및 화재예방을 위한 중요한 인자이다. 본 연구는 ASTM D2155식 발화온도 측정장치를 사용하여 Ethylene Glycol과 물을 혼합한 시료의 자연발화 특성을 고찰하였다. Ethylene Glycol 100%는 시료량 $75{\mu}l{\sim}160{\mu}l$의 범위에서 $434^{\circ}C$로 나타났다. 물을 첨가하여 Ethylene Glycol 80%와 물 20%를 혼합한 시료는 시료량 $100{\mu}l{\sim}125{\mu}l$의 범위에서 $434^{\circ}C$로 나타났고, Ethylene Glycol 60%와 물 40%를 혼합한 시료에서 시료량 $120{\mu}l{\sim}160{\mu}l$의 범위에서 $437^{\circ}C$로 나타났다. 또한 순간발화온도는 시료량 $125{\mu}l$에서 각각 $579^{\circ}C$, $595^{\circ}C$ 및 $611^{\circ}C$를 구하였으며, 물의 비율이 증가할수록 자연발화온도와 순간발화온도는 증가되는 것으로 나타났다.

• BMB Reports
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• 제40권1호
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• pp.125-129
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• 2007

Neurofilament-L (NF-L) is a major element of the neuronal cytoskeleton and is essential for neuronal survival. Moreover, abnormalities in NF-L result in neurodegenerative disorders. Carnosine and the related endogeneous histidine dipeptides prevent protein modifications such as oxidation and glycation. In the present study, we investigated whether histidine dipeptides, carnosine, homocarnosine, or anserine protect NF-L against oxidative modification during reaction between cytochrome c and $H_2O_2$. Carnosine, homocarnosine and anserine all prevented cytochrome c/$H_2O_2$-mediated NF-L aggregation. In addition, these compounds also effectively inhibited the formation of dityrosine, and this inhibition was found to be associated with the reduced formations of oxidatively modified proteins. Our results suggest that carnosine and histidine dipeptides have antioxidant effects on brain proteins under pathophysiological conditions leading to degenerative damage, such as, those caused by neurodegenerative disorders.

• 한국환경과학회지
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• 제30권11호
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• pp.979-982
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• 2021

This study was conducted to investigate the effects of adding Tenebrio molitor L Powder to broiler feed on fatty acid profiles in broiler breast meat. In total, 180 broiler chicks (1-day old Arbor Acres) were included. The birds were randomly divided into control and treatment groups, with 3 replicate subgroups each(30 birds per subgroup), and fed a diet for 35 days without (control) or with 1% Tenebrio molitor L powder (treatment). Among individual fatty acids, addition of Tenebrio molitor L. powder resulted in slightly higher C18:1n-9, C20:3n-3 and C20:3n-6 contents, and lower C18:2n-6 content compared withcontrols (p<0.05). No remarkable differences in total SFA and total USFA contents were found between groups. In conclusion, inclusion of Tenebrio molitor L. in broiler diets did not improve overall fatty acid profiles.

• 대한본초학회지
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• 제20권4호
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• pp.151-161
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• 2005

Objectives : Our research purpose is to establish the standard identification analysis on C. officinale and L. chuanxiong in Korea and China by PCR-mediated fingerprinting. Methods : The Restriction Fragment Length Polymorphism (RFLP) and Randomly Amplified Polymorphic DNA (RAPD) method was used on Internal Transcribed Spacer (ITS) regions and rbcL regions to compare and discriminate genes extracted from crude drugs as C. officinale and L. chuanxiong in Korea and China. Results : L. chuanxiong Korea and China have very similar polymorphism, whereas L. chuanxiong in Korea and C. officinale have very different polymorphism in RFLP. And restriction enzymes AluI and SacI forms the specific fragment band only in C. officinale, they can be used as RFLP marker on ITS regions to discriminate among the species. Conclusions : The results could be applied in discriminating crude drugs among C. officinale and L. chuanxiong in Korea and China. Also they could be used in controlling drug quality, preserving medicinal plants, and improving plant description.

• Journal of Nutrition and Health
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• 제29권8호
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• pp.881-888
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• 1996

The purpose of this study was to determine whether vitamin B6(B6) deficiency affects fuel utilization and blood cholesterol profile with exercise-training. Twenty-four rats were fed a B6 deficient(-B6) diet or a control (+B6) diet for 5 weeks and either exercised(EX) or nonexercised (NE). EX rats were exercised on treadmill(10$^{\circ}$, 0.5-0.8km/h) for 20 minutes everyday. Glucose(GLU), glycogen (GLY), protein(PRO), trglyceride(TG), free fatty acid(FFA), total cholesterl(TC), HDL-cholesterol(HDL-C) and LDL-choleterol(LDL-C) were compared in plasma(P), liver(L) and skeletal muscle(M) of rats. There was a vitamin effect on the level of P-GLU, P-TG, M-TG, L-GLY, L-PRO and an exercise effect on the level of P-PRO, P-FFA, M-PRO, L-GLY, L-TG, P-TC, P-HDL-C, P-LDL-C. Compared to +B6 rats were lower and there were no differences in P-GLU, P-FFA, P-TG. M-GLY, L-TG, P-TC and P-HDL-C. In EX group, the level of P-TG was higher and M-PRO was lower in -B6 rats. There were no differences in M-GLY, L-TG, P-TC and P-HDL-C. These results suggest that a lowered intake of vitamin B6 may impair the adaptation of animals to fuel metabolism related to a decrease of fatty acid oxidation and attenuates the exercise-traning effect on blood lipid profile.

• 한국축산식품학회지
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• 제44권4호
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• pp.951-965
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• 2024

Lactiplantibacillus plantarum is a valuable potential probiotic species with various proven health-beneficial effects. L. plantarum LM1001 strain was selected among ten strains of L. plantarum based on proteolytic activity on whey proteins. L. plantarum LM1001 produced higher concentrations of total free amino acids and branched-chain amino acids (Ile, Leu, and Val) than other L. plantarum strains. Treatment of C2C12 myotubes with whey protein culture supernatant (1%, 2% and 3%, v/v) using L. plantarum LM1001 significantly increased the expression of myogenic regulatory factors, such as Myf-5, MyoD, and myogenin, reflecting the promotion of myotubes formation (p<0.05). L. plantarum LM1001 displayed β-galactosidase activity but did not produce harmful β-glucuronidase. Thus, the intake of whey protein together with L. plantarum LM1001 has the potential to aid protein digestion and utilization.

• 태양에너지
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• 제6권2호
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• pp.3-14
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• 1986

It is desirable to collect the solar thermal energy at relatively high temperature in order to minimize the size of thermal storage system and to enlarge the scope of solar thermal energy utilization. In this study, to develop a solar collector that has both advantages of collecting solar thermal energy at high temperature and fixing conveniently the collector system for long term period, a cylindrical parabolique concentrating solar collector (M.C.P.C.S.C) was designed, which has several rows of parabolique reflectors and thin thickness such as the flat-plate solar collector, maintaining the optical form of concentrating solar collector. The thermal performance of the M.C.P.C.S.C. newly designed in this study was analysed theoretically and experimentally. The results are summarized as follows: 1) prediction equation for outlet temperature, $T_o$, of heat transfer fluid and for the thermal efficiency, ${\eta}$, of the collector were derived as; o $$T_o=[C+B1_n(\frac{I_c(t)}{pv^3})]T_i$$ o $${\eta}=\frac{A}{A_c}\dot{m}[(C-1)+B1_n(E{\cdot}di^6\frac{I_c(t)}{\dot{m}^3})]\frac{T_i}{I_c(t)}$$ 2) When the insolation on the tilted solar collector surface, $I_c$, was $900-950W/m^2$ and the heat transfer fluid was not circulated in tubular absorber, the maximum temperature on the absorber surface was $100-118^{\circ}C$, this result suggested that the heat transfer fluid could be heated up to $98-116^{\circ}C$. The maximum temperature on the absorber surface was decreased with the increase of the collector shape factor, $L_p/L_w$ 3) There was a good agreement between the experimental and theoretical value of solar collector efficiency, ${\eta}$, which was proportional to the collector shape factor, $L_p/L_w$ 4) It is desirable to continue the study on the relationship between the collector shape factor, $L_p/L_w$, and the thermal efficiency of solar collector.

• 한국재료학회지
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• 제11권8호
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• pp.647-654
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• 2001

Nb 첨가 Zr합금인 Zr-lNb합금과 Zr-lNb-lSn-0.3Fe함금의 석출물 및 산화 특성에 미치는 마지막 열처리 온도의 영향을 알아보기 위하여 최종 열처리 온도를 $450^{\circ}C$에서 $800^{\circ}C$까지 변화시켜 미세조직 및 산화 특성을 조사하였다. 부식 시험은 $400^{\circ}C$ , 수중기 분위기에서 270 일 동안 실시하였으며 X-선 회절법을 이용하여 산화막 결정 구조를 분석하였다. 마지막 열처리 온도가 $600^{\circ}C$ 이상일 때 두 합금 모두 $\beta$-Zr이 관찰되었으며 모두 재결정 이후 마지막 열처리 온도가 상승할수록 석출물의 면적 분율이 증가하는 경향을 나타내었다. 모든 열처리 온도 구간에서 Zr-lNb합금의 부식 저항성이 Zr-lNb-lSn-0.3Fe 합금에 비해 우수하였으며 두 합금 모두 재결정 이후 부식 저항성이 급격히 나빠졌다. 이는 $600^{\circ}C$ 이후 형성된 $\beta$-Zr의 영향으로 밝혀졌다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권10호
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• pp.1461-1468
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• 2014

This study was aimed to examine the antibacterial and antioxidative properties of seven edible plants from Thailand to develop alternative antibiotics as feed additives. The plants include Citrus aurantifolia Swingle (Lime) fruits and its leaves, Sesbania grandiflora L. (Agati sesbania) leaves, Piper sarmentosum Roxb (Wild betal) leaves, Curcuma domestica Valeton (Turmeric) roots, Morinda citrifolia L. (Beach mulberry) leaves, Cassia siamea britt (Siamea cassia) leaves, and Cocos nucifera L. (Coconut) peels. The plants were extracted by methanol, n-hexane, chloroform, ethyl acetate, butanol and water. Antibacterial activities with minimum inhibitory concentration (MIC) were determined by agar diffusion assay against Escherichia coli, Burkholderia sp., Haemopilus somnus, Haemopilus parasuis, and Clostridium perfringens that were considered pathogenic strains in livestock infection. Methanol extracts of C. aurantifolia Swingle fruits and leaves showed the broadest spectrum of antibacterial activities except for C. perfringens. Butanol extract of S. grandiflora L. leaves showed the strongest activity against Burkholderia sp. with MIC, $135{\mu}g/mL$. P. sarmentosum Roxb leaves showed antibacterial activities against E. coli, Burkholderia sp. and H. parasuis. Ethyl acetate and water extracts from C. domesitca Valeton roots showed MIC of $306{\mu}g/mL$ and $183{\mu}g/mL$, respectively against only C. perfringens. Antioxidative activity was determined by 2-diphenyl-2-picryl hydrazyl photometric assay. The methanol extracts of C. aurantifolia Swingle fruits and P. sarmentosum Roxb leaves showed the highest antioxidant activity among all the extracts with 3.46 mg/mL and 2.70 mg/mL effective concentration 50% ($EC_{50}$) values, respectively. Total contents of phenolics and flavonoids were measured from the plant extracts. Methanol extracts of S. grandiflora L. and chloroform extracts of C. domestica Valeton were found to have the highest amount of total phenolics, 41.7 and $47.8{\mu}g/mL$, respectively. Flavonoid content of methanol extracts in S. grandiflora L. T was $22.5{\mu}g/mL$ and the highest among plant extracts tested. These results indicated that C. aurantifolia Swingle, S. grandiflora L., P. sarmentosum Roxb, and C. domestica Valeton have antibacterial and antioxidant activities and can be used as alternative antibiotics or potential feed additives for the control of animal pathogenic bacteria.