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      • ANSYS Q3D 및 HFSS 시뮬레이션에 의한 110kHz 무선 전력 송수신 코일의 전기적 특성해석

        박재환,채석병 한국교통대학교 2015 한국교통대학교 논문집 Vol.50 No.-

        본 연구에서는 컴퓨터 시뮬레이션에 의하여 무선충전 송수신 코일의 인덕턴스 및 전력결합 정도를 시뮬레이션 하였다. ANSYS Q3D 시뮬레이터를 활용하여 송신코일의 L 값을 계산하였고, ANSYS HFSS 시뮬레이터를 활용 하여 코일의 전자계 분포 및 송수신 코일의 전력 결합도를 해석하였다. 권선 직경 0.95mm, 루프 직경 40mm, 10턴, 2층 구조의 송신 코일에 대하여 주파수 110kHz 조건에서 해석할 때, 11.2uH의 L값을 계산하였다. 실제 제작된 코일의 인덕턴스는 시뮬레이션에 의해 계산된 값에 비해 떨어지는 값을 나타내는데, 이는 리츠 구조의 영향 및 제조상의 재질 형상적 오차에 기인한다. 송신-수신 코일의 전력 결합도를 해석하기 위하여 HFSS 시뮬 레이션을 적용하였다. 송신코일은 직경 40mm 10턴 구조의 코일을 설정하고, 수신코일은 직경 40mm 1턴 구조 의 루프를 설정하였다. 이 때, 송수신 코일 이격거리 10mm에서 S21 값은 -46.57dB로 계산되었다. 이격 거리가 증가할수록 S21 값은 감소하였다.

      • 제어 입력에 시간 지연을 갖는 선형 시스템의 견실한 H∞ 제어기 설계

        류석환,김홍락 대구대학교 과학기술연구소 1997 科學技術硏究 Vol.4 No.1

        In this paper, a solution of the H∞ control problem for linear uncertain systems with input time delay is presented. An H∞ norm bounded condition is obtained as a sufficient condition for linear uncertain systems with input time delay. Based upon this sufficient condition, a robust H∞ controller design method which involves the solutions of linear matrix inequalities is developed. A numerical example is solved in order to illustrate the efficacy of the suggested design method.

      • 단백뇨를 보이는 사구체 질환 및 당뇨병성 신병증에서의 Lp(a)

        권태환,김준홍,조성,김석재,김용림,조동규,백미영 경북대학교 병원 1998 경북대학교병원의학연구소논문집 Vol.2 No.1

        Background: Recently there has been evidences that serum Lp(a), an independent risk factor to atherosclerotic cardiovascular diseases, were increased in proteinuric disorders such as nephrotic syndrome and diabetic nephropathy. Methods: We intended to search of altered concentrations of Lp(a) in proteinuric disorder measuring serum Lp(a) concentrations with ELISA in 44 glomerulonephritic patients(25 nephrotic syndrome(NS), 19 non-nephrotic range proteinuric glomerulonephritis(GN), 25 diabetic nephropathy patients(DN), and 31 healthy controls(HC). Also, we compared Lp(a) concentration between glomerulonephritis patients and diabetic nephropathy patients with proteinuria of similar degree. Results: 1) There were significantly increased levels of total choesterol, triglyceride, and LDL-cholesterol in Ns compared to GN, DN, HC. 2) There were significantly increased concentrations of serum Lp(a) in NS compared to HC, but no signiicant difference in serum Lp(a) among NS, GN, and DN. 3) There was no significant difference in serum Lp(a) concentrations between NS & DN with 24 hour urine protein greater than 3.0g. 4) There was no significant difference in serum Lp(a) concentration between GN with 24 hour urine protein greater than 0.5g and less than 1.5g and DN with proteinuria of simial degree. 5) In glomerulonephritis patients, there was negative correlation between serum Lp(a) concentration and serum albumin level but correlation with 24 hour urinary protein, total cholesterol, Ldl-cholesterol, and HDL-cholesterol was not shown. In diabetic nephropathy, there was no significant correlation among serum Lp(a) concentration and all parameters including serum albumin, 24 hour urinary protein, and other lipid profiles. Conclusion: The present study confirmed that patients with nephrotic syndrome of diverse etiologies have makedly increased plasma level of Lp(a), in conjunction with other lipid abnormalities. However, this study shows no difference in Lp(a) concentrations between diabetic nephropathy and glomerulonephritis with similar degree of proteinuria.

      • 불확실한 시변 파라메터를 갖는 선형시스템의 고장검출 시스템 설계

        류석환 대구대학교 2005 대구대학교 학술논문집 Vol.1 No.1

        본 연구에서는 시변 파라메터 불확실성을 갖는 선형시스템의 고장검출 시스템 설계를 다룬다. 고장 검출 시스템은 플랜트의 입력과 출력으로부터 오차신호를 발생시키기 위하여 불확실성을 갖는 플랜트의 동적 방정식을 왼쪽 소인수 분해를 이용한다. 이 오차신호로부터 효과적으로 제어시스템의 센서나 액츄에이터의 고장을 실시간으로 검출하기 위하여 고장검출 필터를 설계한다. 본 연구에서 제시한 방법의 효용성을 보여주기 위해서 원자력 발전소의 증기발생기 수위제어시스템에 본 연구의 결과를 적용하여 컴퓨터 모의실험을 수행한다. This paper deals with a fault detection system design for linear systems with uncertain time varying parameters. In order to generate a residual signal, we use a left coprime factorization of the plant dynamic equation with uncertainties. We also design a fault detection filter to effectively detect the fault occurences of the control systems. From the filtered output of the residual signal generator, we can detect sensor or actuator faults effectively. A simulation study with nuclear steam generator level control system shows that the presented method can detect the sensor fault or actuator fault effectively.

      • KCI등재

        규산질다공체와 무기첨가물의 수중 인 제거 효과

        박명환,한명수,이석준,안치용,윤병대,오희목 한국육수학회 2002 생태와 환경 Vol.35 No.3

        The CellCaSi, a porous silicate material, was tested for the removal of phosphorus(Pas phosphate) n water. The effect of the CellCaSi was investigated on the basis of both particle size(under 1, 2 and 4㎜) and added amount(0, 1, 2.5, 5, and 10g/ℓ) of the CellCaSi. The removal efficiency of phosphorus was highest with a particle size of under 1㎜ and also increased with an increasing amount of the CellCaSi. The pH change showed little effect on the phosphorus removal of the CellCaSi. The calcium ion was eluted from the CellCaSi into the water, while the aluminium and iron were not. The eluted calcium ion was combined with dissolved phosphorus and then precipitated. The highest removal efficiency of phosphorus was obtained by the combined addition of the CellCaSi, calcium chloride, and ferric chloride. That is, the phosphorus concentrations of 0.10 and 1.0 ㎎/ℓdecreased to 0.03 and 0.47 ㎎/ℓ by the addition of the CellCaSi(1 g/ℓ), calcium ion(30 ㎎/ℓ), and ferric ion(1 ㎎/ℓ) at day 8 after treatment. The water qualities at the end of the experiment were as follows:pH was 8.1 and conductivity was 318 ??S/㎝ for raw and potable waters).

      • 체적제어를 이용한 신뢰성 기반 위상 최적화

        박재용,황승민,임민규,오영규,박재용,한석영 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

        This paper presents a reliability-based topology optimization (RBTO) using bi-directional evolutionary structural optimization (BESO). An actual design involves uncertain conditions such as material property, operational load and dimensional variation. Deterministic topology optimization (DTO) is obtained without considering of uncertainties related to the uncertainty parameters. However, the RBTO can consider the uncertainty variables because it has the probabilistic constraints. In this paper, the reliability index approach (RIA) is adopted to evaluate the probabilistic constraint. RBTO based on BESO starting from various design domains produces a similar optimal topology each other. Numerical examples are presented to compare the DTO with the RBTO.

      • 불확실한 파라미터와 유연한 관절을 갖는 로보트 매니퓰레이터를 위한 견실한 비선형 제어

        이희영,류석환 대구대학교 과학기술연구소 1994 科學技術硏究 Vol.1 No.-

        In this paper, a robust controller design problem for robot manipulators with parameter uncertainty and flexible joints is considered. The system dynamics of the robot manipulator is expressed as a nonlinear singularly perturbed system. Based on the singular perturbation theory, a robust slow control law is developed such that the control law stabilizes the slow subsystem for allowable parameter uncertainty. Based on this slow control law, a corrective control law is synthesized using the integral manifold theory. In order to demonstrate the efficacy of the proposed controller, computer simulation is performed for a robot

      • KCI등재후보

        다기능성을 갖는 철도 차량용 승차감 측정시스템 개발

        김영국,김석원,박찬경,김기환,박태원 한국센서학회 2004 센서학회지 Vol.13 No.5

        Recently. the "ride comfort" problem becomes increasingly important because of today's needs for train speedup. The concept of term "ride comfort" is equivocal. Generally it is defined as the vehicle vibration. There are many studies on evaluation method of ride comfort for railway. But each of them recommends the different assessment method and the different guidance. In general, the evaluation methods defined in the standards. such as ISO 2631 and UIC 513R, and Ride Index suggested by Sperling. have been used in the railroad. But, only one or two methods of these can be evaluated by using the commercial ride comfort measuring system. Therefore, it is necessary to develop the new ride comfort measuring system for railway with multi-function. In this paper, the generalization of "ride comfort" and the design and verification of new ride comfort measuring system for railway with multi-function have been described and the application examples has been introduced.

      • Benzoate, m-Toluate, Phenol의 Pseudomonas putida에 의한 생분해

        김장규,김석형,김태환,이대광,김남기 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.1

        It this study, basic data were obtained for the treatment of industrial waste water which includes aromatic compounds. Substrate concentrations used were 100ppm, 500ppm, and 1,000pprn and initial pH's were pH6, pH7, and pH8 in order to obtain the optimum conditions for treating benzoate, m-toluate, and phenol by Pseudomonas putida(KCTC 1644). Durations were 20hrs for 100ppm, 40hrs for 500ppm, and 60hrs for 1,000ppm before the static growth of Pseudomonas putida. 100% of 100ppm benzoate(0.31g cell/1) was biodegraded at pH6, pH7, and pH8 before 20hrs, 52.8% of 500ppm at pH8 in 40hrs, and 27.9% of 1,000ppm at pH8 in 60hrs. The best initial pH was pH8 for the biodegradation and the growth of Pseudomonas putida in benzoate medium. For m-toluate, the best initial pH was also pH8. At this pH, 40.6% of 10Dppm(0.31 cell/1), 21.9% of 500ppm, and 14.1% of 1,000ppm m-toluate were biodegraded respectively in limited time. But for phenol, the best initial pH was pH7. At this point, 9.8% of 100ppm(0.218 cell/1), 7.1% of 500ppm, and 4.7% of 1,000ppm phenol were biodegraded respectively. Therefore, the best carbon source in this experiment was benzoate. Pseudomonas putida was also able to biodegrade m-cresol, p-hydroxybenzoic acid, and benzaldehyde.

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