• 한국진공학회지
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• 제10권3호
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• pp.321-327
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• 2001

Radio frequency magnetron sputtering방법으로 타켈의 Ti/si 조성과 $N_2$ 유량을 변화시켜 증착한 다양한 조성비의 Ti-Si-N 박막의 비저항 변화와 확산방지능력을 조사하였다. 높은 Si 함량을 포함한 Ti-Si-N박막내의 Si은 주로 비정질의 $Si_3N_4$ 형태로 존재하였으며 $N_2$의 양이 증가함에 따라 비저항도 증가하였다. 반면, 낮은 Si 함량을 포함한 Ti-Si-N박막은 낮은 $N_2$ 유량에서도 결정질의 TiN이 형성되었고 낮은 비저항을 나타내었다. 또한, 박막내의 N의 양이 증가함에 따라, 높은 박막의 밀도와 압축응력을 갖는 Ti-Si-N이 형성되었으며, 이는 박막 내의 N의 함량이 확산방지능력에 영향을 미치는 가장 중요한 요소 중 하나로 판단된다. 결과적으로, 29~49 at.%, Ti, 6~20 at.% Si, 45~55 at.% N 범위의 조성을 갖는 Ti-Si-N박막이 우수한 확산 억제 능력을 보유하면서 또한 낮은 비저항 특성을 나타내는데 적합한 조성 범위로 나타났다.

• Journal of Ecology and Environment
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• 제31권3호
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• pp.167-176
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• 2008

Atmospheric N deposition has far-reaching impacts on forest ecosystems, including on-site impacts such as soil acidification, fertilization, and nutrient imbalances, and off-site environmental impacts such as nitrate leaching and nitrous oxide emission. Although chronic N deposition has been believed to lead to forest N saturation, recent evidence suggests that N retention capacity, particularly in the forest floor, can be surprisingly high even under high N deposition. This review aims to provide an overview of N retention processes in the forest floor and the implications of changing C-N interactions for C sequestration. The fate of available N in forest soils has been explained by the competitive balance between tree roots, soil heterotrophs, and nitrifiers. However, high rates of N retention have been observed in numerous N addition experiments without noticeable increases in tree growth and soil respiration. Alternative hypotheses have been proposed to explain the gap between the input and loss of N in N-enriched, C-limited systems, including abiotic immobilization and mycorrhizal assimilation, both of which do not require additional C sources to incorporate N in soil N pools. Different fates of N in the forest floor have different implications for C sequestration. N-induced tree growth can enhance C accumulation in tree biomass as observed across temperate regions. C loss from forests can amount to or outweigh C gain in N-saturated, declining forests, while another type of 'C-N decoupling' can have positive or neutral effects on soil C sequestration through hampered organic matter decomposition or abiotic N immobilization, respectively.

• 한국재료학회지
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• 제9권1호
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• pp.42-45
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• 1999

The room temperature optical transmission spectra of GaN /InGaN/GaN single quantum wells (SQW) and InGaN/GaN heterostructures grwon by low pressure metalorganic chemical vapor deposition have been measured. The dependence of the absorption edges of the GaN/InGaN/GaN SQW on the well width has been determined from the transmission spectra. The result shows that the absorption edge of GaN/InGaN/GaN SQW shifts towards lower energy as increasing the well width. The dependence of the absorption edges of the InGaN/GaN heterostructures on InN mole fraction has also been determined from the transmission spectra. The result is compared with calculated values obtained from Vegards's laws. Our result shows a good agreement with the calculated values.

• Journal of Nutrition and Health
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• 제28권2호
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• pp.95-106
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• 1995

The effects of various n-6/n-3 ratios(about 2, 4, 6, 8) of dietary fatty acids on various lipid levels and prostaglandin production were studied at the constant P/S ratio (1.5-1.6) in young (5 weeks old) and adult(8 months old) Sprague-Dawley rats using palm oil, safflower oil and sardine oil. The concentration of serum cholesterol tended to increase with the increasing n-6/n-3 ratio. The tendency of HDL-cholesterol levels was similar to serum cholesterol levels. These were not apparent differences between young and adults rats. Serum triglyceride levels increased according to increasing n-6/n-3 ratio in young rats. These were generally high in the adult rats compared with the young rats. Though liver cholesterol level tended to increase according to the increasing n-6/n-3 ratio in the young rats. The liver triglyceride level did not change according to the n-6/n-3 ratio. However, these levels were apparently higher in the adult than in the young rats. The fatty acid compositions of phosphatidylcholine(PC) were similar in serum and liver. The arachidonate/linoleate ratios in tissue PC were influenced by the n-6/n-3 ratio. They tended to be lower in the adult rats compared with the young rats. It was suggested that the activity of $\Delta$6-desturase was decreased by aging. Production of platelet thromboxane A2(TXA2)and aortic prostacyclin(PGI2) was not apparently influenced with n-6/n-3 ratio. Whereas the ratio of TXA2/PGI2 was the lowest value at 3.8 of n-6/n-3 ratio, expecially in the young rats. Thus this ratio seemed to be a desirable level to protect atherosclerosis. These results indicate that the lipid level and prostaglandin production were influenced not only by n-6/n-3 ratio(under constant P/S ratio) but by aging, particulary triglycerde level and arachidonic/linoleic acid ratio.

• Asian-Australasian Journal of Animal Sciences
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• 제27권11호
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• pp.1608-1614
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• 2014

The objective of this study was to investigate the different dietary ratios of n-6 to n-3 (n-6/n-3) fatty acid (FA) on performance and n-6/n-3 FA in muscles of broiler chickens. A total of 300 one-day-old Cobb chicks were randomly assigned to 3 treatments of 10 replicates in each (10 birds/replicate). Birds were fed on a corn-soybean meal-based diet containing 1% oil during starter (day 1 to 21) and 2% oil during finisher (day 22 to 39) phases, respectively. Treatments of high, medium and low dietary n-6/n-3 FA were formulated by replacing rice bran oil with linseed oil to achieve n-6/n-3 FA close to >20:1, 10:1 and 5:1, respectively. Average daily gain, average daily feed intake, and feed conversion ratio were similar (p>0.05) among the treatments. Serum glucose, cholesterol and triglycerides concentrations were not affected (p>0.05) by dietary treatments. In breast, concentration of C18:3n-3 was significantly greater (p = 0.001) for medium and low vs high n-6/n-3 FA, while concentrations of C20:5n-3, C22:6n-3, total n-3 FA, and n-6/n-3 FA were significantly higher for low vs medium, and medium vs high dietary n-6/n-3 FA. In contrast, concentrations of C18:2 and mono-unsaturated FA (MUFA) were lower for low vs high dietary n-6/n-3 FA. In thigh muscles, concentrations of C20:5n-3 were higher (p<0.05) for medium and low vs high dietary n-6/n-3 FA, and concentrations of C18:3n-3, C22:6, and n-3 FA were greater (p<0.05) for medium vs high, low vs medium dietary n-6/n-3 FA. However, concentrations of C18:1, MUFA, n-6/n-3 were lower (p<0.05) for low and medium vs high dietary n-6/n-3 FA. In conclusion, lowering the dietary n-6/n-3 FA did not affect the performance of chickens, but enhanced beneficial long-chain n-3 FA and decreased n-6/n-3 FA in chicken breast and thigh, which could be advantageous for obtaining healthy chicken products.

• Journal of applied mathematics & informatics
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• 제5권3호
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• pp.859-866
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• 1998

In this paper we shall prove weak(or strong) convergence of the iterates ${\chi_n} \;and \;{y_n}$ defined by $\chi-{n+1}= \alpha_nTy_n+(1-\alpha_n)S\chi_n , y_n=\beta_nT\chi_n+(1-\beta_n)\chi_n$ for all n$\geq$1, where $\alpha_n$ and $\beta_n$ satisfy 0$\leq\alpha_n,\beta_n\leq$b<1.

• 대한수학회지
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• 제45권5호
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• pp.1393-1404
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• 2008

Let K be a nonempty closed convex subset of a Banach space E. Suppose $\{T_{n}\}$ (n = 1,2,...) is a uniformly asymptotically regular sequence of nonexpansive mappings from K to K such that ${\cap}_{n=1}^{\infty}$ F$\(T_n){\neq}{\phi}$. For $x_0{\in}K$, define $x_{n+1}={\lambda}_{n+1}x_{n}+(1-{\lambda}_{n+1})T_{n+1}x_{n},n{\geq}0$. If ${\lambda}_n{\subset}[0,1]$ satisfies $lim_{n{\rightarrow}{\infty}}{\lambda}_n=0$, we proved that $\{x_n\}$ weakly converges to some $z{\in}F\;as\;n{\rightarrow}{\infty}$ in the framework of reflexive Banach space E which satisfies the Opial's condition or has $Fr{\acute{e}}chet$ differentiable norm or its dual $E^*$ has the Kadec-Klee property. We also obtain that $\{x_n\}$ strongly converges to some $z{\in}F$ in Banach space E if K is a compact subset of E or there exists one map $T{\in}\{T_{n};n=1,2,...\}$ satisfy some compact conditions such as T is semi compact or satisfy Condition A or $lim_{n{\rightarrow}{\infty}}d(x_{n},F(T))=0$ and so on.

• 한국전자파학회논문지
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• 제15권8호
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• pp.752-758
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• 2004

본 논문에서는 MBE로 성장한 AlGaN/InGaN/GaN 에피층으로 제작된 GaN HEMTs의 특성을 분석하였다. 게이트 전극 길이가 0.5 $\mu$m로 제작된 소자는 비교적 평탄한 전류 전달 특성을 나타내었으며 최대 전류 880 mA/mm, 최대 전달정수 156 mS/mm, 그리고 $f_{r}$와 $f_{MAX}$는 각각 17.3 GHz와 28.7 GHz가 측정되었다. 또한 표면 처리되지 않은 AlGaN/InGaN/HEMT의 경우 기존의 AlGaN/GaN HEMT와는 달리 펄스 전류 동작 상태에서 전류 와해 현상(current collapse)이 발생하지 않음이 확인되었다. 이 연구 결과는 InGaN를 채널층으로 사용할 경우 표면에 존재하는 트랩에 의한 전류 와해 현상이 발생하지 않는 고성능, 고출력의 GaN HEMT를 제작할 수 있음을 보여준다....

• 한국정보통신학회논문지
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• 제18권6호
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• pp.1361-1368
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• 2014

본 연구에서는 하이퍼큐브의 망비용을 개선한 계층적 상호연결망 HFCube(n,n), HCN(n,n), HFN(n,n)의 임베딩을 분석한다. 연구 결과는 다음과 같다. 하이퍼큐브 $Q_{2n}$는 HFCube(n,n)에 연장율 3, 밀집율 2에 임베딩 가능하다. HFCube(n,n)은 HFN(n,n)과 HCN(n,n)을 부그래프(subgraph)로 갖고 있다. HFCube(n,n)은 HFN(n,n)에 연장율 3에 사상 가능하고, HFCube(n,n)을 HCN(n,n)으로 임베딩 하는 연장율 비용은 O(n)임을 보인다. 이러한 결과는 각 연결망의 여러 가지 유용한 성질들을 분석하는데 도움이 될 것이다.

• 대한수학회지
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• 제41권3호
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• pp.479-487
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• 2004

Let G be a finite group and N be a normal subgroup of G. We denote by ncc(N) the number of conjugacy classes of N in G and N is called n-decomposable, if ncc(N) = n. Set $K_{G}\;=\;\{ncc(N)$\mid$N{\lhd}G\}$. Let X be a non-empty subset of positive integers. A group G is called X-decomposable, if KG = X. In this paper we characterise the {1, 3, 4}-decomposable finite non-perfect groups. We prove that such a group is isomorphic to Small Group (36, 9), the $9^{th}$ group of order 36 in the small group library of GAP, a metabelian group of order $2^n{2{\frac{n-1}{2}}\;-\;1)$, in which n is odd positive integer and $2{\frac{n-1}{2}}\;-\;1$ is a Mersenne prime or a metabelian group of order $2^n(2{\frac{n}{3}}\;-\;1)$, where 3$\mid$n and $2\frac{n}{3}\;-\;1$ is a Mersenne prime. Moreover, we calculate the set $K_{G}$, for some finite group G.