• Asian-Australasian Journal of Animal Sciences
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• 제25권3호
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• pp.325-334
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• 2012

The objective of this study was to determine the roughage to concentrate (R:C) ratio with rain tree pod meal (RPM) supplementation on in vitro fermentation using gas production technique. The experiment design was a 6${\times}$4 factorial arrangement in a CRD. Factor A was 6 levels of R:C ratio (100:0, 80:20, 60:40, 40:60, 20:80 and 0:100) and factor B was 4 levels of RPM (0, 4, 8 and 12 mg). It was found that gas kinetic, extent rate (c) was linearly increased (p<0.01) with an increasing level of concentrate while cumulative gas production (96 h) was higher in R:C of 40:60. In addition, interaction of R:C ratio and RPM level affected $NH_3-N$ and IVDMD and were highest in R:C of 0:100 with 0, 4 mg of RPM and 40:60 with 8 mg of RPM, respectively. Moreover, interaction of R:C ratio and RPM level significantly increased total volatile fatty acids and propionate concentration whereas lower acetate, acetate to propionate ratios and $CH_4$ production in R:C of 20:80 with 8 mg of RPM. Moreover, the two factors, R:C ratio and RPM level influenced the protozoal population and the percentage of methanogens in the total bacteria population. In addition, the use of real-time PCR found that a high level of concentrate in the diet remarkably decreased three cellulolytic bacteria numbers (F. succinogenes, R. flavefaciens and R. albus). Based on this study, it is suggested that the ratio of R:C at 40:60 and RPM level at 12 mg could improve ruminal fluid fermentation in terms of reducing fermentation losses, thus improving VFA profiles and ruminal ecology.

• 한국환경과학회지
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• 제27권1호
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• pp.39-45
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• 2018

In this study, the International Maritime Organization (IMO)'s guideline MEPC. 277 (64) was developed and evaluated for the removal efficiency of T-N in a SBR and MBR combined process. This combined process of resized equipment based on large capacity water treatment device for a protection of marine aquatic life. In this experiment, T-N concentration of influent and effluent was measured through with the artificial wastewater. The SBR reactor operation time was varied according to the C : N : P ratios so that different conditions for mixing and aeration period in mins (90 : 60, 80 : 40, 70 : 50) and two C: N: P ratios (10 : 5 : 3, 10 : 3 : 1) were used. During experiment in the reactor's aeration and anoxic tank DO concentrations were 3 mg/L and 0.2 mg/L respectively. Furthermore, in the reactor MLSS concentration was 2000 mg/L and flowrate was 2 L/hr. Experiment results showed that C : N : P, 10 : 3 : 1 ratio with 90 mins mixing and 60 mins aeration maximized removal efficiency at 97.3% T-N as compared to other conditions. The application of the SBR and MBR combined process showed efficient results.

• Journal of Nutrition and Health
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• 제29권1호
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• pp.122-133
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• 1996

As ciarette smoking adversely affects vitamin C metabolism in humans, smokers need substantially more vitamin C intake than do non-smokers to achieve similar serum vitamin C concentration. To provide the basic information currently available for the determination of vitamin C requirement for Korean smokers, we investigated the differences the serum vitamin C values between smokers(n=53) and non-smokers(n=62) in relation to their intake of the vitamin through diet in 115 male college students, who had not been using vitamin C supplements. Dietary intakes of vitamin C were determined by a 24-hour recall, and serum vitamin C was determined using the 2, 4-dinitrophenylhydrazine method. The mean vitamin C intakes of smokers and non-smokers were consuming less than 75% of the Koeran RDA for vitamin c in their diet. Smokers consumed yellow and green leafy vegetables more often (P=0.02) and fresh fruits less often(P=0.006) than non-smokers. The mean serum vitamin C concentration of smokers consuming the same amounts of vitamine C as non-smokers, 64.3 umol/1, were 20% lower than for non-smokers, 80.1 umol/l(P<0.05). The risk of low serum vitamin C concentration (LoC) among smokers were 3.8% compared with 1.6% in non-smokers, and the odd ratio for LoC risk was 2.43. There were no correlations between dietary and serum vitamin C for smokers and non-smokers. It was concluded that smokers might require at least 20% more vitamin C to reach the same concentration comparable to non-smokers.

• 태양에너지
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• 제14권2호
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• pp.51-60
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• 1994

본 연구에서는 Furan foundry sand 유동층에서 유동화 특성과 Single spiral coil tube에 대한 열전달 특성을 실험하였으며, 전열관의 Pitch와 직경의 비(p/Do=1.58, 2.37, 3.17, 4.75) 및 전열관의 Pitch와 유동입자 크기의 비(p/dp=21.25, 25.15, 30.18, 35.93)가 전열특성에 미치는 영향을 실험적으로 연구하였다. 그 결과 다음과 같은 결론을 얻었다. 1) p/Do가 증가 할수록 평균 열전달계수는 증가한다. 2) 평균 Nusselt수의 증가율은 p/Do=4.75일 때보다 1.58 일 때가 더 크다. 3) 평균 Nusselt수와 Re수, $Pr_g$수 및 p/dp의 상관 관계식은 다음과 같이 나타낼 수 있었다. $Nu_{mean}=C\;Re^m\;Pr_g^{0.4}(p/dp)^n$.

• 한국환경보건학회지
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• 제29권1호
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• pp.43-50
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• 2003

This study was performed to compare the effects of rice straw and towage sludge cake as bulking materials on temperature, pH, weight and volume reduction, porosity, C/N ratio, salinity, and conductivity in aerobic composting of food wastes. Volume ratios of food wastes to rice straw in reactor control, RS-1, RS-2, RS-3 and RS-4 were 4:0, 4:1, 4:2, 4:3 and 4:4, respectively. Weight ratios of food wastes to sewage sludge rake in reactor control, SL-1, SL-2, SL-3 and SL-4 were 4:0, 4:1, 4:2, 4:3 and 4:4, respectively. Reactors were operated for 24 days with 1 hour stirring by 1 rpm and 2 hours aeration per day. The values of pH of food waters, rice straw and sewage sludge cake were 4.39, 7.40 and 5.79, respectively. The lowering of the volume ratio of food wastes to rice straw resulted in the high reaction temperature and the fast weight and volume reduction rates. The lowering of the weight ratio of food wastes to sewage sludge cake resulted in the slow weight and volume reduction rates. C/N ratio in control was larger than that in rice straw containing reactors, and that in rice straw containing reactors was larger than that in sewage sludge cake containing reactors. Salinity and conductivity in reactors were condensed and increased by reaction days.

• Transactions on Electrical and Electronic Materials
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• 제10권4호
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• pp.121-124
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• 2009

In this study, in order to develop compositions of ceramics suitable for piezoelectric actuator and ultrasonic vibrator applications using low temperature sintering, multilayer, PMN-PNN-PZT ceramics were fabricated using $Li_2CO_3$ and $Na_2CO_3$ as sintering aids. Their structural, piezoelectric and dielectric characteristics were investigated according to the Zr/Ti ratio. As the Zr/Ti ratio increased, the electromechanical coupling factor $k_p$, and piezoelectric constant $d_{33}$ and the mechanical quality factor $Q_m$ all increased with Zr/Ti ratio and then decreased after the ratio exceeded 50/50. At the ratio of Zr/Ti =49/51 and sintering temperature of $900^{\circ}C$; the density, electromechanical coupling factor $k_p$, dielectric constant ${\varepsilon}_r$ piezoelectric $d_{33}$ constant and mechanical quality factor $Q_m$ all showed the optimum values of 7.900 $g/cm^3$, 0.576, 856, 312 pC/N, 1,326, respectively. These property values are very suitable for multilayer ceramics actuator applications.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.481-485
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• 2002

본 연구에서는 수직형 LPE 장치를 이용하여 meltback 방법으로 제작된 PBH-LD에 대한 누설전류를 해석하였다. PBH-LD에서 활성층 이외의 p-n 다이오드와 p-n-p-n 전류차단층과 같은 누설경로에 따른 이들의 영향을 조사하였다. 이러한 누설전류의 영향을 알아보기 위해 누설 폭이 "0" 일 때와 누설 폭이 $W_{ι}$ 일 때를 비교하였다. 그 결과 누설 폭에 따른 임계전류는 누설 폭을 줄이거나, 고유저항 ($\rho$$_{ι}$$\rho$$_{a}$ )비를 증가시켜줌으로써 임계전류가 낮아짐을 확인하였다. 본 연구에서 제작된 LD의 경우 활성층의 폭 $W_{a}$ 가 약 1.4$\mu\textrm{m}$이고 누설 폭이 약 0.6$\mu\textrm{m}$로, 제작된 LD의 cavity length와 임계전류를 비교해 본 결과 고유저항비가 약 0.5일 때 누설 폭에 따른 계산된 임계전류값과 실제 제작된 PBH-LD의 임계전류값이 일치함을 확인하였다. 따라서, 제작된 PBH-LD의 p-InP 차단층의 도핑농도를 $10^{18}$ c $m_{-3}$ 에서 $10^{17}$ $cm^{-3}$으로 줄여 누설영역의 저항을 크게 함으로써 누설전류를 더 줄일 수 있으리라 생각된다.다.

• Asian-Australasian Journal of Animal Sciences
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• 제28권12호
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• pp.1736-1741
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• 2015

The objective of this study was to determine the effect of forage: concentrate ratio (F:C) on growth performance, ruminal fermentation and blood metabolites of housing-feeding yaks. Thirty-two Maiwa male yaks (initial body weight = $207.99{\pm}3.31kg$) were randomly assigned to four dietary treatments (8 yaks per treatment). Experimental diets were: A, B, C, D which contained 70:30, 60:40, 50:50 and 40:60 F:C ratios, respectively. Dry matter intake and average daily gain in yaks fed the C and D diets were greater (p<0.05) than yaks fed the A and B diets. No differences were found in ruminal $NH_3-N$, total volatile fatty acids, acetate, butyrate, valerate, and isovalerate concentrations. The propionate concentration was increased (p<0.05) in the C and D groups compared with the A and B diets. In contrast, the acetate to propionate ratio was decreased and was lowest (p<0.05) in the C group relative to the A and B diets, but was similar with the D group. For blood metabolites, no differences were found in serum concentrations of urea-N, albumin, triglyceride, cholesterol, low density lipoprotein, alanine aminotransferase, and aspartate aminotransferase (p>0.05) among treatments. Treatment C had a higher concentration of total protein and high density lipoprotein (p<0.05) than A and B groups. In addition, there was a trend that the globulin concentration of A group was lower than other treatments (p = 0.079). Results from this study suggest that increasing the level of concentrate from 30% to 50% exerted a positive effect on growth performance, rumen fermentation and blood metabolites in yaks.

• Nutrition Research and Practice
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• 제15권3호
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• pp.367-381
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• 2021

BACKGROUND/OBJECTIVES: This study aimed to establish a mother and child cohort in the Chinese population, and investigate human breastmilk (HBM) composition and its relationship with maternal body mass index (BMI) and infant growth during the first 3 mon of life. SUBJECTS/METHODS: A total of 101 Chinese mother and infant pairs were included in this prospective cohort. Alterations in the milk macronutrients of Chinese mothers at 1 mon (T1), 2 mon (T2), and 3 mon (T3) lactation were analyzed. HBM fatty acid (FA) profiles were measured by gas chromatography (GC), and HBM proteomic profiling was achieved by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). RESULTS: During the first 3 mon of lactation (P < 0.05), significant decreases were determined in the levels of total energy, fat, protein, and osteopontin (OPN), as well as ratios of long-chain saturated FA (including C16:0, C22:0 and C24:0), monounsaturated FA (including C16:1), and n-6 poly unsaturated FA (PUFA) (including C20:3n-6 and C20:4n-6, and n-6/n-3). Conversely, butyrate, C6:0 and n-3 PUFA C18:3n-3 (α-linolenic acid, ALA) were significantly increased during the first 3 mon (P < 0.05). HBM proteomic analyses distinguished compositional protein differences over time (P = 0.001). Personalized motherinfant analyses demonstrated that HBM from high BMI mothers presented increased total energy, fat, protein and OPN, and increased content of n-6 PUFA (including C18:3n-6, C20:3n-6 and n-6/n-3 ratio) as compared with low BMI mothers (P < 0.05). Furthermore, BMI of the mothers positively correlated with the head circumference (HC) of infants as well as the specific n-6 PUFA C20:3n-6 over the 3 time points examined. Infant HC was negatively associated with C18:0. CONCLUSION: This study provides additional evidence to the Chinese HBM database, and further knowledge of FA function. It also helps to establish future maternal strategies that support the healthy growth and development of Chinese infants.

• 한국식품영양과학회지
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• 제19권6호
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• pp.641-645
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• 1990

In order to study the influence of culture conditions on cell growth and lipid formation by Mucor sp, various carbon and nitrogen sources initial pH and C./N ratio of medium were investigated. Glucose was found to be suitable carbon source in terms of lipid yield and ${\gamma}$-linolenic acid(GLA) content. When NH4Cl and (NH4)2SO4 were used as nitrogen source lipid content was high(19-21%) but GLA content was low(15-17%) On the other hand when NaNO3 and KNO3 were used lipid content was low(about 13%) but GLA content was high(22-23%). The highest production of lipid was obtained at a C/N ratio of 40 using glucose and (NH4)2SO4 as carbon and nitrogen source respectively. it was found that lipid yield was high at pH4.6 Also this fungus did not grow at 35$^{\circ}C$ and lipid yield was highr at 15$^{\circ}C$ than $25^{\circ}C$.