• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.206-207
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• 2009

PECVD를 이용하여 상온에서 Silicon nitride 박막을 제조하였다. 그리고 증착 중에 non-invasive ion energy analyzer를 이용하여 이온에너지와 이온에너지 flux룰 측정하였다. PECVD의 소스 파워는 500W, 바이어스 파워 100W으로 고정하고 주파수 250Hz으로 고정된 상태에서 펄스를 인가하여 duty ratio를 30-100%까지 변화시켰다. 작은 duty ratio 범위 (30-70%)에서 duty ratio가 감소할 때, 이온에너지와 이온에너지의 비가 감소하였다. 이 때 감소되는 굴절률은 저이온에너지 변수와 강한 연관성을 지니고 있었다. 굴절률은 1.65-2.46 사이에서 변화하였다.

• 한국정밀공학회지
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• 제20권1호
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• pp.144-150
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• 2003

When WC and group IV elements are added to Ti(C,N)-Ni substrate, microstructures of the cermet is changed. The microstructure gives direct effect on the property of the material. In this study, the amount of WC and group W elements of Ti(C,N) cermet tool was investigated. The composition of WC was changed from 5 to 20wt% to determine the effect of WC on the cutting performance of cermet tool. The more WC was added, the longer the tool life of the cermet tool was. The cermet with 20wt% WC showed the best fracture toughness. The effect of group W elements; ZrC, ZrN and HfC was also investigated by adding each of them to manufacture the cermet tool with fixed l4wt% WC composition. The cermet with 1wt% ZrC and 14wt% WC showed the best cutting performance among the investigated cermet tools.

• 대한수학회보
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• 제57권1호
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• pp.81-93
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• 2020

Let m ∈ ℕ₀, p > 1 and $${\alpha}^{[m,p]}(x)\;:\;{\sqrt{x}},\;\{{\sqrt{\frac{(m+n-1)p-(m+n-2)}{(m+n)p-(m+n-1)}}}\}^{\infty}_{n=1}$$. In this paper, we consider the backward extensions of Bergman-type weighted shift W_α^[m,p](x). We consider its subnormality, k-hyponormality and positive quadratic hyponormality. Our results include all the results on Bergman weighted shift W_α(x) with m ∈ ℕ and $${\alpha}(x)\;:\;{\sqrt{x}},\;{\sqrt{\frac{m}{m+1}},\;{\sqrt{\frac{m}{m+2}},\;{\sqrt{\frac{m+2}{m+3}},{\cdots}$$.

• The Korean Journal of Ceramics
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• 제4권4호
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• pp.377-381
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• 1998

Wear behaviors of unidirectionally oriented $Si_3N_{4w)/Si_3N_4$ composites, sintered at different temperatures with different alignments of whiskers, have been studied in parallel and perpendicular sliding directions with respect to the orientation of the whiskers by using a ball-on-disk reciprocating sliding apparatus. The results show that wear rate in parallel direction is much greater than that in perpendicular direction. With decreasing alignment of the whiskers, the wear rate decreases in parallel sliding direction and increases in perpendicular direction. With increasing sintering temperature, the wear rate increases obviously in both parallel and perpendicular directions.

• 월간한국양록
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• 18호
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• pp.2-10
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• 1993

본 시험은 3마리의 2년생 famale sika deer에게 동일한 에너지 수준하에 단백질 함량($7\%,\;12\%\;17\%$)이 각기 다른 사료를 급여하였을 때, 사료 영양소의 이용성 변화 및 체내 N 대사, 유지를 위한 단백질 요구량, 대사성 분질소 함량 등을 규명하기 위하여 실시하였으며, 결과를 요약하면 다음과 같다. 1. DM, OM, ADF의 소화율을 사료내 단백질 함량에 따른 차이를 보이지 않았으며(P>.1), CP의 소화율은 사료내 단백질 수준이 증가함에 따라 향상되었다(P<.05). 2. 사료내 단백질 함량이 증가함에 따라 분과 뇨로의 N 배출량 모두 증가하였으며(P<.05), 사료내 단백질 수준이 7, 12, $17\%$ 이었을 때 N retention은 각각 26.9, 31, 8, $38.9\%$였다. 3. 혈증 urea-N 함량은 사료내 단백질 함량의 증가에 따라 현저하게 증가하였다.(P<.05) 4. Famale sika deer의 유지수준의 단백질요구량(protein requirement for maintenance)은 $1.81g/kgW^{0.75}/d$다. 5. 대사성 분 질소(metabolic facal N)함량은 $0.32g/kgW^{0.75}/d$였다.

• Bulletin of the Korean Chemical Society
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• 제7권2호
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• pp.108-110
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• 1986

The solution epr spectra of ${\alpha}-1,2,3-[H_nPV(IV)V_2W_9O_{40}]^{(7-n)-}$were measured at various pH and three protonated species have been identified. The spectrum of $H_3PV(IV)Ⅴ_2$ consisting of 8 lines indicates that the V-OH-V bridge prevents effectively the electron transfer between the vanadium atoms. The spectrum of $H_2PV(IV)V_2$ consisting of 15 lines can be interpreted by assuming that the electron is hopping fast between the two vanadium atoms in the V-O-V sequence. The multi-line spectrum of $HPV(IV)V_2$ is interpreted as a poorly resolved 43-line spectrum which originates from the electron hopping among the three vanadium atoms with the forward and backward transition probabilities of 4:1 in the OH-V-O-V sequence.

• Current Optics and Photonics
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• 제6권4호
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• pp.367-374
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• 2022

A photodetector based on a reduced graphene oxide (RGO)/n-Si heterojunction with high responsivity, detectivity and fast response speed is presented. Here, we put forward a simple vacuum filtration method to prepare RGO film and transfer it onto an n-Si substrate to form an RGO/n-Si heterojunction. The experimental results show that the heterojunction has good rectification characteristics, and the response and recovery time are less than 0.31 s and 0.25 s, respectively. Under 470 nm light conditions at -2 V applied voltage, the responsivity and detectivity of the device are 65 mA/W and 4.02 × 10¹⁰ cmHz^1/2W^-1, respectively. The simple preparation process and good performance of the RGO/n-Si heterojunction make it a promising material for photoelectric detection, especially in the near-ultraviolet band.

• 대한수학회보
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• 제31권1호
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• pp.105-113
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• 1994

In the course of study of dendroids, Czuba [3] introduced a notion of $R^{i}$ -continua which is a generalization of R-arc [1]. He showed a new class of non-contractible dendroids, namely of dendroids which contain an $R^{i}$ -continuum. Subsecequently Charatonik [2] attempted to extend the notion into hyperspace C(X) of metric continuum X. In so doing, there were some oversights in extending some of the results relating $R^{i}$ -continua of dendroids for metric continua. In fact, Proposition 1 in [2] is false (see example C below) and his proof of Theorem 6 in [2] is not correct (Take Example 4 in [4] with K = [e,e'] as an $R^{1}$-continuum of X and work it out. Then one seens that K not .mem. K as he claimed otherwise.). The aims of this paper are to introduce a notion of w-regular convergence which is weaker than 0-regular convergence and to prove that the w-regular convergence of a sequence {Xn}$^{\infty}$$_{n=1}$ to $X_{0}$ of subcontinua of a metric continuum X is a necessary and sufficient for the sequence {C( $X_{n}$)}$^{\infty}$$_{n=1}$ to converge to C( $X_{0}$ ), and also to prove that if a metric continuum X contains an $R^{i}$ -continuum with w-regular convergence, then the hyperspace C(X) of X contains $R^{i}$ -continuum.inuum.uum.

• 전자공학회논문지S
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• 제36S권6호
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• pp.9-16
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• 1999

이 논문에서는 렘펠의 D-준동현사상을 바탕으로 하여 드브루인 수열을 만드는 효과적인 알고리즘을 제안한다. 이 알고리즘에서는 k차 드브루인 수열에서 n차 드브루인 수열의 다음 비트을 만드는데 필요한 배타논리합 연산수는, r의 2진 표현에서 1의 갯수를 W(r)이라 쓸 때, $k(2^{W(n-k)}-1)$쯤임을 보인다: 딸서, 드브루인 함수를 잘 고르면 이 수는 k가 된다.

• Journal of Applied Biological Chemistry
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• 제59권4호
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• pp.289-298
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• 2016

FK506 hyper-yielding mutant, called the TCM8594 strain, was made from Streptomyces tsukubaensis NRRL 18488 by mutagenesis using N-methyl-N'-nitro-N-nitrosoguanidine, ultraviolet irradiation, and FK506 sequential resistance selection. FK506 production by the TCM8594 strain improved 45.1-fold ($505.4{\mu}g/mL$) compared to that of S. tsukubaensis NRRL 18488 ($11.2{\mu}g/mL$). Among the five substrates, wheat bran was selected as the best solid substrate to produce optimum quantities of FK506 ($382.7{\mu}g/g$ substrate) under solid-state fermentation, and the process parameters affecting FK506 production were optimized. Maximum FK506 yield ($897.4{\mu}g/g$ substrate) was achieved by optimizing process parameters, such as wheat bran with 5 % (w/w) dextrin and yeast extract as additional nutrients, 70 % (v/w) initial solid substrate moisture content, initial medium pH of 7.2, $30^{\circ}C$ incubation temperature, inoculum level that was 10 % (v/w) of the cell mass equivalent, and a 10 day incubation. The results showed an overall 234 % increase in FK506 production after optimizing the process parameters.