• Title/Summary/Keyword: Stability Limits

검색결과 356건 처리시간 0.035초

전력 수송능력 증대를 위한 FACTS의 전력계통 적용효과 연구 (The Study of FACTS Application Effects for Power Transmission Capability Enhancement in Power System)

  • 장병훈;이근준;김영한
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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    • pp.117-122
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    • 1996
  • This paper presents the study results of FACTS application effect for transmission capability Enhancement. In a study of the application of series and shunt compensation to the mid and long term KEPCO system in 2000 and 2006 year, it was concluded that the successful application of FACTS would ve capable of controlling power flow in KEPCO system with incr eased transfers without exceeding existing thermal and dynamic stability limits.

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Stable Degradation of Benzoate by Klebsiella oxytoca C302 Immobilized in Alginate and Polyurethane

  • Kim, Jun-Ho;Jeong, Won-Hwa;T.B. Karegoudar;Kim, Chi-Kyung
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제7권6호
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    • pp.347-351
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    • 2002
  • Benzoate produced from the degradative pathways of various aromatic chemicals is generally recognized as a pollutant compound. However, various bacterial strains isolated as benzoate degraders have exhibited certain limits to their functions, including a loss of viability and degradability when cultivated in a broth medium for a longer time. Accordingly, immobilization techniques have been utilized to overcome such problems, and the current study examined the use of alginate and polyurethane for immobilizing Klebsiella oxytoca C302 to extend its viability and degradability of benzoate. The organism was well encapsulated by both matrices and the immobilized cells showed a high stability as regards their viability and degradability of 2 mM benzoate in a MM2 broth medium during cultivation for longer than 60 h in a semicontinuous batch system.

에너지함수법을 이용한 ATC 계산에 관한 연구 (A Study for ATC Computation Using an Energy Function Method)

  • 김양일;정성원;김재현
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 제38회 하계학술대회
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    • pp.465-466
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    • 2007
  • Available transfer capability(ATC) quantifies the viable increase in real power transfer from one point to another in a power system. ATC calculation has predominantly focussed on steady-state viability. In many power systems, point-to-point transfer is not restricted by steady-state limits, but by undesirable dynamic behavior following large disturbance. In this paper, an energy function method for transient stability ATC computation is proposed, which utilizes a between the potential energy and energy function.

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DC-Voltage Regulation for Solar-Variable Speed Hybrid System

  • Niyitegeka, Gedeon;Lee, Kyungkyu;Choi, Jaeho
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2015년도 추계학술대회 논문집
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    • pp.123-124
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    • 2015
  • Recently interest on DC systems has been grown up extensively for more efficient connection with renewable energy. During the operation, there happens DC_link voltage variations. This paper focuses on the DC voltage stabilization applied in stand-alone DC microgrid to improve the system stability by keeping the voltage within limits. Batteries and a variable speed diesel generator cover the shortage of power after all available renewable energy is consumed. Load shedding or power generation reduction should automatically takes place if the maximum tolerable voltage variation is exceeded. PSIM based simulation results are presented to evaluate the performance of the proposed control measures.

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동적 특성을 고려한 상주 양진당의 구조 안전성 평가 (Structural Safety Evaluation of Yangjindang in Sang-ju Using Vibration Characteristics)

  • 이가윤;이성민;김시윤;이기학
    • 한국공간구조학회논문집
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    • 제19권1호
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    • pp.37-44
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    • 2019
  • Yangjindang house, which is located in Sang-ju province of South Korea, is one of the special Hanok structures dated back to Joseon dynasty. This study aims to examine structural safety of the Yangjindang wood frame building considering dynamic parameters such as the natural frequency and damping ratio. The numerical model of the wood frame building is implemented using Midas Gen, especially the wood joint where column and beam were connected. The behavior of the actual frame building was compared with the modeling results. In addition, structure responses such as shear force, axial force, flexural moment and deflections were calculated and compared with the allowable limits. Numerical results show that, generally, despite of some local members shear failure, Yangjindang's structural response does not exceed the limitation according to current standards.

연상법을 이용한 신경계 환자의 임상적 추론 전략 제안 (Suggested Clinical Reasoning Strategies Using a Mnemonic Device for Patients with Neurological Disorders)

  • 우영근
    • PNF and Movement
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    • 제17권1호
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    • pp.145-156
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    • 2019
  • Purpose: This study suggests clinical reasoning strategies for therapists with little experience in clinical reasoning for the evaluation and treatment of patients with neurological disorders. Methods: The suggested method was the mnemonic PT STRESS whose initials represent the body structure and functions that can affect the activity limits and the items that can cause problems at the functional level in patients with neurological disorders. Results: PT STRESS stands for pain (P), ability of the trunk (T), sensation (S), tone (T), range of motion (R), emotion and endurance (E), muscular strength (strength), and stability (S). It tests and measures problems in the body structure and functions. Conclusion: This study suggests easy clinical reasoning strategies that can be used by therapists who have insufficient experience in the evaluation or treatment of patients with neurological disorders. However, more factors need to be considered in the future with regard to clinical reasoning of the diverse problems of patients with neurological disorders.

Polymer Passivation Effect on Methylammonium Lead Halide Perovskite Photodetectors

  • Kim, Hyojung;Byun, Hye Ryung;Kim, Bora;Kim, Sung Hyuk;Oh, Hye Min;Jeong, Mun Seok
    • Journal of the Korean Physical Society
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    • 제73권11호
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    • pp.1675-1678
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    • 2018
  • Methylammonium lead halide ($MAPbI_3$) perovskites are considered as promising materials owing to their excellent optical and electrical properties. However, perovskite materials suffer from degradation in air, which limits their practical applications. Here, we demonstrate successful passivation of the $MAPbI_3$ photodetectors through monochloro-para-xylylene (Parylene-C) deposition. The time-dependent photocurrent characteristics were systematically investigated, and we achieved significantly improved device performance and stability with Parylene-C passivation. Based on the excitation-power-dependent photoluminescence (PL) data, we confirmed that Parylene-C can reduce the carrier losses in $MAPbI_3$, leading to the enhancement of photocurrent and PL in $MAPbI_3$ photodetectors.

Glucose Diffusion Limiting Membrane Based on Polyethyleneimine (PEI) Hydrogel for the Stabilization of Glucose Sensor

  • Kim, Suk-Joon;Shin, Woonsup
    • Journal of Electrochemical Science and Technology
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    • 제12권2호
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    • pp.225-229
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    • 2021
  • Commercially available continuous glucose sensors require the operation stability for more than two weeks. Typically, the sensor comprises a sensing layer and an over-coating layer for the stable operation inside the body. In the sensing layer, enzymes and mediators are cross-linked together for the effective sensing of the glucose. The over-coating layer limits the flux of glucose and works as a biocompatible layer to the body fluids. Here, we report the simple preparation of the flux-limiting layer by the condensation of polyethyleneimine (PEI), tri-epoxide linker, and trimethylolpropane triglycidyl ether (PTGE). The sensor is constructed by a layer-by-layer drop-coating of the sensing layer containing glucose dehydrogenase and the PEI-derived blocking layer. It is stable for more than 14 days, which is enough for the sensor in the continuous monitor glucose monitoring (CGM) system.

Smart modified repetitive-control design for nonlinear structure with tuned mass damper

  • ZY Chen;Ruei-Yuan Wang;Yahui Meng;Timothy Chen
    • Steel and Composite Structures
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    • 제46권1호
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    • pp.107-114
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    • 2023
  • A new intelligent adaptive control scheme was proposed that combines observer disturbance-based adaptive control and fuzzy adaptive control for a composite structure with a mass-adjustable damper. The most important advantage is that the control structures do not need to know the uncertainty limits and the interference effect is eliminated. Three adjustable parameters in LMI are used to control the gain of the 2D fuzzy control. Binary performance indices with weighted matrices are constructed to separately evaluate validation and training performance using the revalidation learning function. Determining the appropriate weight matrix balances control and learning efficiency and prevents large gains in control. It is proved that the stability of the control system can be ensured by a linear matrix theory of equality based on Lyapunov's theory. Simulation results show that the multilevel simulation approach combines accuracy with high computational efficiency. The M-TMD system, by slightly reducing critical joint load amplitudes, can significantly improve the overall response of an uncontrolled structure.

Floating Inverter Amplifiers with Enhanced Voltage Gains Employing Cross-Coupled Body Biasing

  • Jae Hoon Shim
    • 센서학회지
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    • 제33권1호
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    • pp.12-17
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    • 2024
  • Floating inverter amplifiers (FIAs) have recently garnered considerable attention owing to their high energy efficiency and inherent resilience to input common-mode voltages and process-voltage-temperature variations. Since the voltage gain of a simple FIA is low, it is typically cascaded or cascoded to achieve a higher voltage gain. However, cascading poses stability concerns in closed-loop applications, while cascoding limits the output swing. This study introduces a gain-enhanced FIA that features cross-coupled body biasing. Through simulations, it is demonstrated that the proposed FIA designed using a 28-nm complementary metal-oxide-semiconductor technology with a 1-V power supply can achieve a high voltage gain (> 90 dB) suitable for dynamic open-loop applications. The proposed FIA can also be used as a closed-loop amplifier by adjusting the amount of positive feedback due to the cross-coupled body biasing. The capability of achieving a high gain with minimum-length devices makes the proposed FIA a promising candidate for low-power, high-speed sensor interface systems.