• 전자공학회논문지A
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• 제28A권11호
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• pp.910-914
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• 1991

This paper describes the improvement of frequency characteristic of crystal oscillator I.C using Ti-Salicide. The characteristics of transistor(drive current) using Ti-Salicide process are better than Poly-Si process, because the mobility. To know frequency characteristic of oscillator I.C, the simulation is performed using inverter buffer chain of Fan-out 10 TTL. Its result shows at once the generation of normal clock pulse in input signal and the improvement of rising and falling time.

• 정보학연구
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• 제1권2호
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• pp.15-24
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• 1998

본 연구에서 살펴본 바와 같이 컨테이너 운송의 경우 보험단보의 공백구간에서 발생하는 위험을 회피하기 위해서는 운송인 책임의 개시와 위험의 이전시기가 일치되어 있는 컨테이너 정형무역거래조건을 이용해야 한다고 사료되어진다.

• 대한간호
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• 제3권6호통권14호
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• pp.8-12
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• 1964

• 대한수학회보
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• 제58권5호
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• pp.1069-1078
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• 2021

Let R be a commutative ring with identity. A proper ideal I of R is called 1-absorbing primary ([4]) if for all nonunit a, b, c ∈ R such that abc ∈ I, then either ab ∈ I or c ∈ ${\sqrt{1}}$. The concept of 1-absorbing primary ideals in a polynomial ring, in a PID and in idealization of a module is studied. Moreover, we introduce weakly 1-absorbing primary ideals which are generalization of weakly prime ideals and 1-absorbing primary ideals. A proper ideal I of R is called weakly 1-absorbing primary if for all nonunit a, b, c ∈ R such that 0 ≠ abc ∈ I, then either ab ∈ I or c ∈ ${\sqrt{1}}$. Some properties of weakly 1-absorbing primary ideals are investigated. For instance, weakly 1-absorbing primary ideals in decomposable rings are characterized. Among other things, it is proved that if I is a weakly 1-absorbing primary ideal of a ring R and 0 ≠ I₁I₂I₃ ⊆ I for some ideals I₁, I₂, I₃ of R such that I is free triple-zero with respect to I₁I₂I₃, then I₁I₂ ⊆ I or I₃ ⊆ I.

• Journal of Periodontal and Implant Science
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• 제42권6호
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• pp.231-236
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• 2012

Purpose: The aim of this study was to evaluate the influence of the crown-to-implant (C/I) ratio on the change in marginal bone level around the implant and to determine the site-related factors influencing the relationship between the C/I ratio and periimplant marginal bone loss. Methods: A total of 259 implants from 175 patients were evaluated at a mean follow-up of five years. Implants were divided into two groups according to their C/I ratios: ${\leq}$ 1, and >1. Site-related factors having an influence on the relationship between C/I ratio and periimplant marginal bone loss were analyzed according to the implant location, implant diameter, implant manufacturer, prosthesis type, and guided bone regeneration (GBR) procedure. Results: It was found that 1) implants with a C/I ratio below 1 exhibited greater periimplant marginal bone loss than implants with a C/I ratio more than 1, 2) site-related factors had an effect on periimplant marginal bone loss, except for the implant system used, 3) the C/I ratio was the factor having more dominant influence on periimplant marginal bone loss, compared with implant diameter, prosthesis type, implant location, and GBR procedure, 4) implants with a C/I ratio below 1 showed greater periimplant marginal bone loss than implants with a C/I ratio greater than 1 in the maxilla, but not in the mandible, 5) and periimplant marginal bone loss was more affected by the implant system than the C/I ratio. Conclusions: Within the limitations of this study, implants with a higher C/I ratio exhibited less marginal bone loss than implants with a lower C/I ratio in the posterior regions. The C/I ratio was a more dominant factor affecting periimplant marginal bone loss in the maxilla than the mandible. Meanwhile, the implant system was a more dominant factor influencing periimplant marginal bone loss than the C/I ratio.

• 대한수학회논문집
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• 제10권3호
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• pp.499-518
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• 1995

In this paper we consider more systematically the centralizer C(S) of the set $S = {f_a $\mid$ f_a : X \to X ; x \longmapsto x * a, a \in X}$ with respect to the semigroup End(X) of all endomorphisms of an implicative BCK-algebra X with the condition (S). We obtain a series of interesting results. The main results are stated as follows : (1) C(S) with repect to a binary operation * defined in a certain way forms a bounded implicative BCK-algebra with the condition (S). (2) X can be imbedded in C(S) such that X is an ideal of C(S)/ (3) If X is not bounded, it can be imbedded in a bounded subalgebra T of C(S) such that X is a maximal ideal of T. (4) If $X (\neq {0})$ is semisimple, C(S) is BCK-isomorphic to $\prod_{i \in I}{A_i}$ in which ${A_i}_{i \in I}$ is simple ideal family of X.

• 산업공학
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• 제12권2호
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• pp.193-204
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• 1999

Development of high technology especially in telecommunication and precise weapon systems will impact the future battle field environment. So it is not difficult to anticipate the environment of military command and control system will be changed rapidly. Considering these future battle field environment, military needs automated C4I (Command, Control, Communication, Computer and Intelligence) system, namely real time decision support system which is combined high technologies. Most of advanced countries have been studied and developed these kinds of systems and already applied these systems in real military operations. In order to take a military initiative in Korea peninsula it is essential to catch up with this trend and procure C4I system. The purpose of this research is to present the method and the direction of optimal C4I system development model. First we survey the related theory about C4I systems. Second we present the conceptual framework for C4I system concept development. Third we model the system using Timed Petri-Net and perform simulation. Finally we analyze the through-put time and suggest alternatives. If we model using the real organization structure, operational tasks and various situations then optimal C4I system would be developed.

• 태양에너지
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• 제6권2호
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• pp.3-14
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• 1986

It is desirable to collect the solar thermal energy at relatively high temperature in order to minimize the size of thermal storage system and to enlarge the scope of solar thermal energy utilization. In this study, to develop a solar collector that has both advantages of collecting solar thermal energy at high temperature and fixing conveniently the collector system for long term period, a cylindrical parabolique concentrating solar collector (M.C.P.C.S.C) was designed, which has several rows of parabolique reflectors and thin thickness such as the flat-plate solar collector, maintaining the optical form of concentrating solar collector. The thermal performance of the M.C.P.C.S.C. newly designed in this study was analysed theoretically and experimentally. The results are summarized as follows: 1) prediction equation for outlet temperature, $T_o$, of heat transfer fluid and for the thermal efficiency, ${\eta}$, of the collector were derived as; o $$T_o=[C+B1_n(\frac{I_c(t)}{pv^3})]T_i$$ o $${\eta}=\frac{A}{A_c}\dot{m}[(C-1)+B1_n(E{\cdot}di^6\frac{I_c(t)}{\dot{m}^3})]\frac{T_i}{I_c(t)}$$ 2) When the insolation on the tilted solar collector surface, $I_c$, was $900-950W/m^2$ and the heat transfer fluid was not circulated in tubular absorber, the maximum temperature on the absorber surface was $100-118^{\circ}C$, this result suggested that the heat transfer fluid could be heated up to $98-116^{\circ}C$. The maximum temperature on the absorber surface was decreased with the increase of the collector shape factor, $L_p/L_w$ 3) There was a good agreement between the experimental and theoretical value of solar collector efficiency, ${\eta}$, which was proportional to the collector shape factor, $L_p/L_w$ 4) It is desirable to continue the study on the relationship between the collector shape factor, $L_p/L_w$, and the thermal efficiency of solar collector.

• 대한화학회지
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• 제9권4호
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• pp.161-168
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• 1965

$C_6H_6{\cdot}I_2$ 및 $C_6H_6{\cdot}ICI$ 의 두 錯物의 安定度에 미치는 용매의 영향을 자외선 分光光度法으로 硏究하였다. 클로로포름, 시크로헥산 및 n-헥산 용액에서 $C_6H_6{\cdot}I_2$ 생성에 대한 실온에서의 평형상수가 各各 0.090, 0.216 및 0.328$lmole^{-1}$ 이고 $C_6H_6{\cdot}ICI$ 생성에 대한 실온에서의 평형상수가 各各 0.125, 0.676 및 0.639$lmole^{-1}$ 임을 알았다. 이 結果로부터 이들 두 錯物의 安定度가 용매의 誘電常數의 減少와 더불어 增加함을 볼 수 있고 그 增加率이 $C_6H_6{\cdot}I_2$에서 보다 $C_6H_6{\cdot}ICI$에서 더 큼을 알 수 있다. 이 事實로 보아 $C_6H_6^+{\cdots}I_2^-$ 또는 $(C_6H_6)^+{\cdots}Cl^-$型 의 이온 構造다가 이들 錯物의 共鳴安定化에 참여하는 정도가 크며 또 그 참여도가 $C_6H_6{\cdot}I_2$에서 보다 $C_6H_6{\cdot}ICl$에서 더 크다고 생각된다.

• 충청수학회지
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• 제13권1호
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• pp.139-144
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• 2000

The generalized noncommutative torus $T_{\rho}^d$ of rank m was defined in [2]. Assume that for the completely irrational noncommutative subtorus $A_{\rho}$ of rank m of $T_{\rho}^d$ there is no integer q > 1 such that $tr(K_0(A_{\rho}))=\frac{1}{q}{\cdot}tr(K_0(A_{\rho^{\prime}}))$ for $A_{\rho^{\prime}}$ a completely irrational noncommutative torus of rank m. All $C^*$-algebras ${\Gamma}({\eta})$ of sections of locally trivial $C^*$-algebra bundles ${\eta}$ over $M=\prod_{i=1}^{e}S^{2k_i}{\times}\prod_{i=1}^{s}S^{2n_i+1}$, $\prod_{i=1}^{s}\mathbb{PR}_{2n_i}$, or $\prod_{i=1}^{s}L_{k_i}(n_i)$ with fibres $T_{\rho}^d{\otimes}M_c(\mathbb{C})$ were constructed in [6, 7, 8]. We prove that ${\Gamma}({\eta}){\otimes}M_{p^{\infty}}$ is isomorphic to $C(M){\otimes}A_{\rho}{\otimes}M_{cd}(\mathbb{C}){\otimes}M_{p^{\infty}}$ if and only if the set of prime factors of cd is a subset of the set of prime factors of p, that $\mathcal{O}_{2u}{\otimes}{\Gamma}({\eta})$ is isomorphic to $\mathcal{O}_{2u}{\otimes}C(M){\otimes}A_{\rho}{\otimes}M_{cd}(\mathbb{C})$ if and only if cd and 2u - 1 are relatively prime, and that $\mathcal{O}_{\infty}{\otimes}{\Gamma}({\eta})$ is not isomorphic to $\mathcal{O}_{\infty}{\otimes}C(M){\otimes}A_{\rho}{\otimes}M_{cd}(\mathbb{C})$ if cd > 1 when no non-trivial matrix algebra can be ${\Gamma}({\eta})$.