• 공업화학
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• 제23권3호
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• pp.308-312
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• 2012

암모니아를 이용하여 질소가 도핑된 광촉매를 제조하고 이에 따른 가시광 광촉매 활성효과를 알아보았다. 질소 도핑된 $TiO_2$ 광촉매가 태양광영역에서 분해되는 정도를 확인하기 위해서 태양광에 조사하에 메틸렌블루 염료분해 실험을 수행하였다. SEM 이미지 분석결과 질소가 도핑된 $TiO_2$ 광촉매의 응집 입자가 감소함을 알 수 있었고, XRD 결과 $600^{\circ}C$에서 열처리된 질소 도핑 $TiO_2$ 광촉매는 아나타제 구조와 루타일이 존재하고 있음을 알 수 있었다. 또한, X선 광전자 분광기 분석을 통하여 암모니아 반응시간에 따라서 $TiO_2$ 광촉매에 N의 조성 증가를 알 수 있었다. $TiO_2$ 광촉매의 질소 도핑에 의하여 메틸렌블루에 대한 광분해 효과가 도핑되지 않은 시료에 비해 증가하였다. 또한 질소 도핑은 $TiO_2$ 광촉매의 결정에도 영향을 주었다.

• 한국환경과학회지
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• 제14권12호
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• pp.1093-1102
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• 2005

Effects of abscisic acid(ABA) and temperature on the anthocyanin accumulation and phenylalanine ammonia Iyase(PAL) activity were investigated in seedlings of Arabidopsis thaliana. In time course study, exogenous application of ABA $(50-1000\;{\mu}M)$ led to a noticeable increase in anthocyanin pigments which persisted over the following 5 days. Anthocyanins increased in concert with the chlorophyll loss. The activity of PAL, a key enzyme in the phenylpropanoid pathway, increased on exposure to ABA and reached maximum on the 4th day, This result shows that anthocyanin synthesis and PAL activity have a close physiological relationships. In the effects of temperatures ($10^{\circ}C,\;17^{\circ}C,\;25^{\circ}C$and $30^{\circ}C$) on anthocyanin accumulation and PAL activity in seedlings, a moderate-low temperatures ($17^{\circ}C$) enhanced both anthocyanin content and PAL activity, whereas elevated temperatures ($30^{\circ}C$) showed low levels of anthocyanin and PAL activity, suggesting a correlation between temperature-induced anthocyanin synthesis and the accumulation of PAL mRNA. Simultaneous application of ABA with temperatures Induced higher anthocyanin synthesis and PAL activity in seedlings than ABA or temperature stress alone. Moderate-low temperature with ABA exposure elicited the maximal induction of anthocyanin synthesis and PAL activity. Therefore, ABA treatment significantly increased thermotolerance in .A. thalinan seedlings. Ethephon and ABA showed similar mode of action in physiological effects on anthocyanin accumulation and PAL activity. Our data support that anthocyanins may be protective in preventing damage caused by environmental stresses and play an important role in the acquisition of freezing tolerance.

• Asian-Australasian Journal of Animal Sciences
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• 제19권2호
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• pp.181-188
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• 2006

The objective of this research was to determine the effects of synchronizing the rate of dietary energy and nitrogen release on: ruminal fermentation, microbial protein synthesis, blood urea nitrogen, and nutrient digestibility in beef cattle. Four, two-and-a-half year old Brahman-Thai native crossbred steers were selected for the project. Each steer was fitted with a rumen cannula and proximal duodenal cannula. The steers were then randomly assigned in a $4{\times}4$ Latin square design to receive four dietary treatments. Prior to formulation of the dietary treatments, feed ingredients were analyzed for chemical composition and a nylon bag technique was used to analyze the treatments various ingredients for degradability. The treatments were organized in four levels of a synchrony index (0.39, 0.50, 0.62 and 0.74). The results showed that dry matter digestibility trend to be increased (p<0.06), organic matter and acid detergent fiber digestibility increased linearly (p<0.05), while crude protein and neutral detergent fiber digestibility were not significantly different (p>0.05). Higher concentration and fluctuation of ruminal ammonia and blood urea were observed in the animal that received the lower synchrony index diets. As the levels of the synchrony index increased, the concentrations of ruminal ammonia nitrogen and blood urea nitrogen, at the 4 h post feeding, decreased linearly (p<0.05). Total volatile fatty acid and bacteria populations at the 4 h post feeding increased linearly (p<0.05). Microbial protein synthesis trend to be increase (p<0.08). The results of this research indicate that synchronizing the rate of degradation of dietary energy and nitrogen release improves ruminal fermentation, microbial protein synthesis and feed utilization.

• Asian-Australasian Journal of Animal Sciences
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• 제14권6호
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• pp.885-893
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• 2001

This review summarizes some recent research into ways of improving the productivity of ruminal fermentation by increasing protein flow from the rumen and decreasing the breakdown of protein that results from the action of ruminal microorganisms. Proteinases derived from the plant seem to be of importance to the overall process of proteolysis in grazing animals. Thus, altering the expression of proteinases in grasses may be a way of improving their nutritive value for ruminants. Inhibiting rumen microbial activity in ammonia formation remains an important objective: new ways of inhibiting peptide and amino acid breakdown are described. Rumen protozoa cause much of the bacterial protein turnover which occurs in the rumen. The major impact of defaunation on N recycling in the sheep rumen is described. Alternatively, if the efficiency of microbial protein synthesis can be increased by judicious addition of certain individual amino acids, protein flow from ruminal fermentation may be increased. Proline may be a key amino acid for non-cellulolytic bacteria, while phenylalanine is important for cellulolytic species. Inhibiting rumen wall tissue breakdown appears to be an important mechanism by which the antibiotic, flavomycin, improves N retention in ruminants. A role for Fusobacterium necrophorum seems likely, and alternative methods for its regulation are required, since growth-promoting antibiotics will soon be banned in many countries.

• Mycobiology
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• 제39권4호
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• pp.257-265
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• 2011

L-Phenylalanine is one of the essential amino acids that cannot be synthesized in mammals in adequate amounts to meet the requirements for protein synthesis. Fungi and plants are able to synthesize phenylalanine via the shikimic acid pathway. L-Phenylalanine, derived from the shikimic acid pathway, is used directly for protein synthesis in plants or metabolized through the phenylpropanoid pathway. This phenylpropanoid metabolism leads to the biosynthesis of a wide array of phenylpropanoid secondary products. The first step in this metabolic sequence involves the action of phenylalanine ammonialyase (PAL). The discovery of PAL enzyme in fungi and the detection of $^{14}CO_2$ production from $^{14}C$-ring-labeled phenylalanine and cinnamic acid demonstrated that certain fungi can degrade phenylalanine by a pathway involving an initial deamination to cinnamic acid, as happens in plants. In this review, we provide background information on PAL and a recent update on the presence of PAL genes in fungi.

• 공업화학
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• 제25권3호
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• pp.337-339
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• 2014

본 연구의 내용은 Dimethyl terephthalate의 생성 과정 중 필연적으로 생성되는 부산물인 Methyl 4-formylbenzoate를 이용해 one-pot reaction을 통한 p-Aminobenzoic acid를 얻는 방법이다. 이 방법은 Methyl 4-formylbenzoate에 chlorine gas와 methylene chloride를 이용해 acid chloride를 형성하고 ammonia gas를 통해 amide를 중간체로 가진다. 생성된 amide는 Hofmann degradation을 통해 p-Aminobenzoic acid로 전환된다. 이 방법은 폐기물인 Methyl 4-formylbenzoate를 재활용하여 기존의 p-Aminobenzoic acid를 수율 90%로 합성하였으며 이는 기존의 p-Aminobenzoic acid 생산과정을 대체할 수 있을 것으로 예상된다.

• 대한화학회지
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• 제7권4호
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• pp.230-237
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• 1963

2-Methyl-5,5'-gem-disubstituted-$\Delta^2$-thiazoline系 化合物의 合成을 1,1'-gem-dusubstituted thiiranes의 三員環을 ammonis로 開環하여 骸當하는 N-또는 S-acetyl-amino mercaptan을 얻고 그것을 다시 閉環하는 方法과 또 하나는 같은 三員環인 gem-disubstitutes imines을 thiolacetic acid 로 開環하고 그것을 直接 다시 閉環하여 얻은 두가지 方法에 의하여 硏究하엿다. 前者는 thiirane ring은 gem-disubtitution의 compression 效果에 의하여 極히 安定化되어 여러가지 强力한 反應條件下에서의 sodium amide를 利用한 ammonia nuclephile에 頑强한 抵抗을 나타냈으며 反對로 後者의 三員環 imine은 같은 gem-disubstitution 效果를 받음에도 不拘하고 容易하게 開環하였다. 이 gem-disubstitution 效果에 의한 環狀化合物의 開環阻止性과 閉環促進性을 立體化學的인 見地에서 考察하였으며 本硏究로서 環狀化合物의 安定性에 미치는 gem-disubstitution의 compression 效果는 所謂 Thorpe-Ingold bond angle deformation에 緣由하는 것이 아니고 오히려 gem-dusubstituents와 異節環狀化物內의 hetero atom(s)이 미치는 bond interaction에 起因하다는 結論을 얻었다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권9호
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• pp.1255-1261
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• 2005

The objective of this study was to evaluate the net flux response of nitrogen compounds (alpha-amino N, ammonia N, urea N, essential amino acids) across the portal-drained viscera (PDV), liver and total splanchnic tissues of mature wethers to increasing level of dietary fishmeal (FM) supplementation. Four wethers (average body weight, 64 kg) with chronic indwelling catheters into the portal, hepatic and mesenteric veins and the abdominal aorta were used in a 4${\times}$4 Latin square design. A basal diet consisting of 0.7 hay and 0.3 concentrate was fed twice daily with a fixed amount at 1.4 times maintenance energy (1.3 kg/day on a dry matter basis). The supplementation proportion of FM as treatment was 0, 0.03, 0.06 and 0.09 to the amount of the basal diet to contain 119, 137, 154 and 170 g crude protein per kg dietary dry matter, respectively. Blood flows through PDV and liver did not differ (p>0.05) among the treatments. Both net PDV release and hepatic uptake of alpha amino acid N increased linearly (p<0.05) in response to increased dietary FM, which resulted in similar total splanchnic release of alpha-amino N among the treatments. Similarly, increased dietary FM increased net PDV absorption and hepatic removal of ammonia N linearly (p<0.05). Hepatic synthesis and total splanchnic release of urea N increased linearly (p<0.01) with increased dietary FM, but PDV uptake of urea N did not respond to increased dietary FM. Linear regression equations between the increases in FM N intake and PDV net flux indicated that 0.34 and 0.30 of FM N was absorbed in the form of alpha-amino N and ammonia N, respectively. The results demonstrated that FM supplementation provides more alpha-amino N than ammonia N to the liver, but the alpha-amino acid N absorption is less than the expected metabolizable protein N from FM supplementation.

• 한국분말재료학회지
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• 제13권6호
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• pp.432-438
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• 2006

Aluminum nitride (AlN) nanopowders with low degree of agglomeration and uniform particle size were synthesized by carbothermal reduction of alumina and subsequent direct nitridization. Boehmite powder was homogeneously admixed with carbon black nanopowders by ball milling. The powder mixture was treated under ammonia atmosphere to synthesize AlN powder at lour temperature. The effect of process variables such as boehmite/carbon black powder ratio, reaction temperature and reaction time on the synthesis of AlN nanopowder was investigated.

• Bulletin of the Korean Chemical Society
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• 제23권8호
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• pp.1103-1105
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• 2002

H-ZSM-5 and γ-alumina were treated with formaldehyde and sodium carbonate. The treatment increased the amounts of weak acid sites, removing strong acid sites. The maximum temperature of weak acid sites in their ammonia TPD spectra shifted in the direction of high temperature. The modified H-ZSM-5 and g-alumina were mixed with the methanol synthesis catalyst to perform dimethyl ether synthesis from syn-gas. The modified catalysts showed better selectivity to dimethyl ether, minimizing the reforming reaction to carbon dioxide. The maximum yield of 53.3% to dimethyl ether was achieved under the reaction conditions of 54.4 atm, 523 K, and the feed rate of 4500 Lhr-1 .gcat-1.