• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.55-61
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• 1993

An application of the optoacoustic detection method to investigate the catalytic effect of a perovskite, $Gd_{1-x}Sr_xCoO_{3-y}$ (x = 0.00, 0.25, 0.50, 0.75) system, in the oxidation reaction of CO is described. The optoacoustic signals Of $CO_2$ produced from the oxidation reaction were measured for differing x values in $Gd_{1-x}Sr_xCoO_{3-y}$. By monitoring optoacoustic signals with respect to the time, the concentration ratios of CO and $O_2$, and the temperature, the kinetic information on the catalytic properties of the perovskite for CO oxidation reaction can be obtained. The effect of Sr substitution in $Gd_{1-x}Sr_xCoO_{3-y}$ has been found to show the maximum catalytic effect at x = 0.25 and the substantial increase in catalytic activity at temperatures above 200$^{\circ}C$. It demonstrates that the optoacoustic detection method allows the investigation of the integrated catalytic effect not only for the oxidation reaction of CO, but also for many reactions, in general, by continuously and directly detecting the species associated with the reactions.

• Korean Journal of Poultry Science
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• v.29 no.2
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• pp.135-140
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• 2002

An experiment was conducted to determine the effects of vitamin C supplementation on the performance and egg quality of layers. A total of 800 ISA Brown layers of 71 weeks old were assigned to one of the following diets containing 0, 3, 10, 50 or 100 ppm LG-vitamin C, 100ppm free ascorbic acid, 100 ppm Rovimix stay C-35 or 50 ppm LG-vitamin C supplemented with 100 ppm Zn methionine chelate. The feeding trial was conducted for flour weeks during the period of May to June when the average ambient temperature was $23.8^{\circ}C$ (5 :00 PM). Each treatment was replicated five times with 20 birds housed in 2 birds cage units. Vitamin C supplementation did not improve the overall performances (egg Production and egg Quality). Birds fed 100 ppm of LG vitamin C had the lowest egg Production while birds fed 100 ppm of Rovimix-35 had the lowest egg weight among birds fed different sources of vitamin C. Although supplementation of vitamin C over 50 ppm increased soft and broken egg Production, supplementation of 10 ppm LG vitamin C showed lowest soft and broken egg Production among all treatments. E99she11 thickness was highest in the treatment of 50 ppm LG vitamin C. In conclusion, supplementation of vitamin C at the level of 3 ~ 100 ppm did not significantly influence the laying performance and eggshell quality of laying hens under normal ambient(20 ~$26^{\circ}C$ ) condition.

• Journal of the Korean Wood Science and Technology
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• v.35 no.1
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• pp.17-26
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• 2007

This study was conducted to investigate the effects of End-coating (CO) treatment and Vapor-dam (V) treatment on the air circulating oven drying characteristics of green stock (Paulownia tomentosa) for drum. The reduction of the weight of specimens was greatly displayed in order of control (C-NC) treatment, End-coating (C-CO) treatment, Vapor-dam (V-NC) treatment and Vapor-dam/End-coating (V-CO) treatment after the beginning of drying. The V-CO treated specimen showed smoother temperature gradient compared with the V-NC treated specimen throughout whole drying stage and there was little temperature gradient between the inner and outer part of the cylindrical stock. The C-CO treated specimen showed higher value of vapor pressure in both the inner and outer part of the cylindrical stock until the middle stage of drying, while after the middle stage of drying only the inner part of the cylindrical stock presented higher value compared with the C-NC treated specimen. The distribution of the absolute vapor pressure of the V-CO treated specimen was similar to that of the V-NC treated specimen during the initial stage of drying. However, the former showed a large distribution in order of the hollow, the outer part, the inner part of the cylindrical stock after the initial stage of drying, which was entirely different model of distribution from that of the V-NC treated specimen. Surface checks and ring failures were not observed for all of the specimens, while end checks were severely occurred for the C-NC treated specimen and the V-NC treated specimen.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.84-84
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• 2000

수소화된 비정질 실리콘(a-Si:H)과 미세결정질 실리콘 ($\mu$c-Si:H)은 저온.건식 공정인 PECVD로 값싼 유리 기판을 사용하여 넓은 면적에 증착이 가능하다는 큰 장점으로 인해 광전소자(photovoltaic device)와 박막 트랜지스터(TFTs)등에 폭넓게 응용되어 왔으며 최근에는 nm 크기의 실리콘 결정(nc-Si)에서 가시광선 영역의 발광 현상이 발견됨에 따라 광소자로서의 특성을 제어하기 위해서는 성장 조건과 공정 변수에 따른 구조 변화에 대한 연구가 선행되어야 한다. 본 연구에서는 UHV-ECR-PECVD 법을 이용하여 H2로 희석된 SiH4로부터 a-Si:H과 $\mu$c-Si:H를 증착하였다. 그림 1은 SiH4 20sccm/H2 50sccm/25$0^{\circ}C$에서 기판의 DC bias를 변화시키면서 박막을 증착시킬 때 나타나는 박막의 구조 변화를 raman spectrum의 To phonon peak의 위치와 반가폭의 변화로 나타낸 것이다. 비정질 실리콘 박막은 DC bias를 증가시킴에 따라 무질서도가 증가하다가 어떤 critical DC bias에서 최대치를 이룬후 다시 질서도가 증가한다. 이온의 충격력에 의해 박막내에 응력이 축적되면 박막의 에너지 상태가 높아지고 이 축적된 응력이 ordering에 대한 에너지 장벽을 넘을 수 있을 만큼 커지게 되면 응력이 풀리면서 ordering이 가능해지는 것으로 생각된다. 그림 2는 수소 결합 형태의 변화이다. 박막의 무질서도가 증가할 경우 알려진 바와 같이 2000cm-1근처의 peak은 감소하고 2100cm-1 부근이 peak이 증가하는 현상을 보였다. 본 논문에서는 여러 공정 변수, 특히 DC bias에 따르는 박막의 구조 변화와 다른 성장 조건(온도, 유량비)이 critical DC bias나 결정화, 결정성 등에 미치는 영향에 대한 분석결과를 보고하고자 한다.등을 이용하여 광학적 밴드갭, 광흡수 계수, Tauc Plot, 그리고 파장대별 빛의 투과도의 변화를 분석하였으며 각 변수가 변화함에 따라 광학적 밴드갭의 변화를 정량적으로 조사함으로써 분자결합상태와 밴드갭과 광 흡수 계수간의상관관계를 규명하였고, 각 변수에 따른 표면의 조도를 확인하였다. 비정질 Si1-xCx 박막을 증착하여 특성을 분석한 결과 성장된 박막의 성장률은 Carbonfid의 증가에 따라 다른 성장특성을 보였고, Silcne(SiH4) 가스량의 감소와 함께 박막의 성장률이 둔화됨을 볼 수 있다. 또한 Silane 가스량이 적어지는 영역에서는 가스량의 감소에 의해 성장속도가 둔화됨을 볼 수 있다. 또한 Silane 가스량이 적어지는 영역에서는 가스량의 감소에 의해 성장속도가 줄어들어 성장률이 Silane가스량에 의해 지배됨을 볼 수 있다. UV-VIS spectrophotometer에 의한 비정질 SiC 박막의 투과도와 파장과의 관계에 있어 유리를 기판으로 사용했으므로 유리의투과도를 감안했으며, 유리에 대한 상대적인 비율 관계로 투과도를 나타냈었다. 또한 비저질 SiC 박막의 흡수계수는 Ellipsometry에 의해 측정된 Δ과 Ψ값을 이용하여 시뮬레이션한 결과로 비정질 SiC 박막의 두께를 이용하여 구하였다. 또한 Tauc Plot을 통해 박막의 optical band gap을 2.6~3.7eV로 조절할 수 있었다. 20$0^{\circ}C$이상으로 증가시켜도 광투과율은 큰 변화를 나타내지 않았다.부터 전분-지질복합제의 형성 촉진이 시사되었다.이것으로 인하여 호화억제에 의한 노화 방지효과가 기대되었지만 실제로 빵의 노화는 현저히 진행되었다. 이것은 quinua 대체량 증가에 따른 반죽의 안정성이 저하되어 버린 것으로 생각되어진다. 더욱이 lipase를 첨가하면 반죽이 분화하는 경향이 보여졌지만 첨가량 75ppm에 있어서 상당히 비용적의 증대가 보였다. 이것은 lipase의 가수분해에 의해

• The Korean Journal of Food And Nutrition
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• v.28 no.3
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• pp.422-427
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• 2015

This study was carried out to investigate the microbiological contamination levels of Dutch coffee products marketed in Korea. The temperature conditions during distribution and storage were also considered in this experiment. Retailed Dutch coffee were purchased from regional cafes, that is, these were self-blended by the cafes, and the marketed products were purchased from department stores and from Internet sites. The 21 samples were blended in a coffee house and 9 were obtained from department stores or were delivered from internet sites. House blended Dutch coffee contained $35.2{\pm}15.8CFU/mL$ of general bacteria, and this increased to $78.4{\pm}29.7CFU/mL$ at room temperature or $51.2{\pm}32.1CFU/mL$ after refrigeration for 5 days. These almost reached the highest criteria level for the Korea Food Sanitation Law. After 10 days, the count increased to $98.5{\pm}58.4CFU/mL$ at room temperature and $86.7{\pm}44.2CFU/mL$ at refrigeration temperature. In the Dutch coffee for distribution, $39.6{\pm}20.1CFU/mL$ of general bacteria were detected, but these did not increase after 5 days or 10 days both for room temperature and under refrigeration. The Coliform group was not found in any kind of Dutch coffee, and Fungi was founded in 60% of the Dutch samples purchased in coffee houses, department stores, and shopping sites mall. On day 0 day, $2.6{\pm}1.7CFU/mL$ of fungi were detected in the coffee house Dutch, and it did not increase significantly during the storage period at room and in a cold temperature. $3.5{\pm}3.4CFU/mL$ of fungi were detected in the Dutch coffee for distribution, and it didn't increase during further storage under any temperature.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.1
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• pp.103-113
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• 1993

Every year, over $3.37{\times}10^7$ ton of municipal solid waste is generated in Korea, of which about 28% is organic food waste from restaurant, dining halls and households etc. Methane conversion of the food waste by anaerobic digestion could be a viable approach for energy recovery as well as safe disposal of the waste. However, as food waste is composed of highmolecular complex polymers such as cellulose, lignin and protein, anaerobic digestion of food waste has not been efficient in terms of volumetric loading rate, solid retention time and extent of anaerobic degradation. In this research, the improved anaerobic degradation of food waste was attemped by applying rumen microorganisms to anaerobic digestion. Acidification efficiency of food waste by rumen microorganisms was compared with that of conventional acidogenesis. And optimum acidification conditions by rumen microorganisms were also determined. For the experiments, anaerobic batch reactors of 600 mL was fed with the processed (dried and milled) food waste obtained from a restaurant. Ultimate volatile fatty acid (VFA) yield produced by rumen microorganisms was about 8.4 meq VFA/g volatile solid (VS) that is 95% of the theoretical value. This yield was not much different from that of conventional acidogenesis, but hydrolysis rate was about twice faster. Cumulative VFA concentration increased from 66 meq/L to 480 meq/L, when the initial TS was increased from 1% to 15%. But VFA yield at 15% TS was half of that at 1% TS. This inhibition on the acidification might be caused by the rapid drop of pH and higher concentration of nonionized VFA. Optimal pH and temperature range for the acidification were about 6.0~7.5 and $35{\sim}45^{\circ}C$, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.514-520
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• 2014

In this study, the production potential of alternative coagulant ($Al_2(SO_4)_3$ solution) having the identical coagulation activity with respect to the commercial coagulant was investigated. The raw material of alternative coagulant was a spent catalyst including aluminium (waste activated alumina) generated in the manufacturing process of the polymer. The alternative coagulant was produced through a series of processes: 1) intense heat and grinding, 2) chemical polymerization and substitution with $H_2SO_4$ solution, 3) dissolution and dilution and 4) settling and separation. To determine the optimal operating conditions in the lab-scale autoclave and dissolver, the content of $Al_2O_3$ in alternative coagulant was analyzed according to changes of the purity of sulfuric acid, reaction temperature, injection ratio of sulfuric acid and water in the dissolver. The results showed that the alternative coagulant having the $Al_2O_3$ content of 7~8% was produced under the optimal conditions such as $H_2SO_4$ purity of 50%, reaction temperature of $120^{\circ}C$, injection ratio of $H_2SO_4$ of 5 times and injection ratio of water of 2.3 times in dissolver. In order to evaluate the coagulation activity of the alternative coagulant, the Jar-test was conducted to the effluent in aerobic reactor. As a result, in both cases of Al/P mole of 1.5 and 2.0, the coagulation activity of the alternative coagulant was higher than that of the existing commercial coagulant. When the production costs were compared between the alternative and commercial coagulant through economic analysis, the production cost reduction of about 50% was available in the case of the alternative coagulant. In addition, it was identified that the alternative coagulant could be applied at field wastewater treatment plant without environmental problem through ecological toxicity testing.

• Journal of Korean Society of Forest Science
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• v.37 no.1
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• pp.17-30
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• 1978

Press drying was used on italian poplar (Populus euamericana) to find the profitable means of drying. This study was designed to investigate the process of platen drying considering core temperature, drying time, current moisture content, drying rate, shrinkage and recovery, and green volume specific gravity, equilibrium moisture content and dimensional stability of press dried material and air dried material, The drying tests were conducted using 1.5 centimeter thick material at platen temperature of $175^{\circ}C$. The results were summarized as follows. 1. Core temperature was divided into three stages of drying characterized by period initial heating, plateau temperature and rising core temperature. Plateau temperature was 114 to $119^{\circ}C$. 2. The following predicting equations of drying time(y) in different core temperatures were developed for initial thickness($x_1$), initial moisture content ($x_2$) and final moisture content ($x_3$) 3. The predicting equaltion of current moisture content(u) was log u=4.658-0.060t as funtion of drying time(t) and that of drying rate(r) was log r=-2.797-0.049t. Current moisture content and drying rate of air drying were shown in figure 2. 4. The predicting equation of shrinkage in thickness direction(y) was log y=1.933+0.038t as function of drying time(t), and that of expansion in width direction was $y=-0.692+0.043t-0.001t^2$. 5. Thickness shrinkage was increased more than proportional at to pressure increase. Width shrinkage and thickness recovery was greatest at 35psi. 6. Green volume specific gravity of press dried material was 25% greater than that of air dried material. But equilibrium moisture content of press dried material was less 24% than that of air dried material. Antishrinkage efficiency of press dried material were obtained 27.7%.

• Journal of Animal Environmental Science
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• v.18 no.1
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• pp.1-8
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• 2012

The study was conducted to investigate the effects of climate on indoor environment of a swine house with natural. This study was tested in the beef swine stall at Young-in, Kyung-ki do. The test was experimented for the effect of interior environment by the outdoor environment and the interior-pan. The results are as follows. 1. In test 1 ($T_{out}$ : $25.7^{\circ}C$, without fan), an indoor air flow pattern was showed that entered from sidewall winch-curtain to went out of a indoor by the ridge winch-curtain. And the velocity of a section of the center was measured two times as large as the velocity of the floor. It is the acceleration of the velocity by thermal buoyancy. And, the entered air was rapidly dissipated by flow energy. So that in the swain livestock with sidewall winch-curtain is effected by thermal buoyancy. And the air temperature of the indoor was distributed more higher as compared with the outdoor temperature. This result is caused by the sensible heat from swine and the ventilation is restricted. 2. In test 2 (($T_{out}$ : $25.7^{\circ}C$, with fan), the velocity of a section of the center was measured more higher as compared with the test 1. And the variance of air velocity was distributed higher as compared with the test 1. This result is showed dead region of air flow with a fan operation. And, the variance of gas density was distributed lower as compared with the test 1.

• Microbiology and Biotechnology Letters
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• v.3 no.3
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• pp.123-134
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• 1975

Out of 96 yeast strains isolated from various natural habitats, five strains were screened based on their ability to ferment agricultural biproducts such as rice-, barley-and wheat-bran, and sawdust. These were identified as Hansenula anomala var anomala, Candide utilis, C. pelliculosa, Debaryomyces hansenii, and Irpex lacteus. Using these yeasts the above mentioned agricultural biproducts were fermented in various combinations. The fermented product was fed to 180 male Starcroses for eight weeks and obtained a body weight increase of 15.1g a day, while the unfermented control feed increased 10.5g a day.