• Food Science and Biotechnology
• /
• 제18권3호
• /
• pp.618-623
• /
• 2009

Synergistic interactions between xanthan (X) and carob (C) were investigated by studying the linear viscoelastic behavior of X, C, and X/C mixtures at sol and gel states. At the solution state, storage modulus (G') dominates the linear viscoelastic properties of X/C mixtures. The gelation temperature (52 to $57^{\circ}C$) was weakly dependent on the xanthan fraction (${\phi}x$) in the mixture. The ${\phi}x$ also had a strong effect on G' until ${\phi}x=0.5$. The elastic active network concentration (EANC) of X/C gels was estimated from the pseudo-equilibrium modulus. The EANC for systems with ${\phi}x=0.25$, 0.5, 0.75, and 1 at 1% total concentration was 2.3, 4.4, 4.1, and 0.32 (${\times}10^{-3}\;mol/m^3$), respectively. The maximum synergistic effect was observed at about ${\phi}x=0.5$. The G' at the transition state of X/C mixed gel was proportional to ${\omega}^{3/2}$ at ${\omega}$>${\omega}_{tr}$ (the onset transition frequency) compared to the theoretical limit of ${\omega}^{1/2}$.

• 한국소음진동공학회논문집
• /
• 제21권11호
• /
• pp.983-990
• /
• 2011

This paper investigates active noise control(ANC) of a rectangular cavity using single channel filtered-x least mean square(FXLMS) algorithms to globally reduce the interior noise. To obtain the global reduction of the interior noise, multichannel active control should be incorporated in general. We, however, examined firstly the optimal location of the secondary source that produces a global reduction of the interior noise field using single channel control. We then investigated the frequency characteristics of the reduction to yield the effective frequency band of the active control system. It follows that the secondary source should be located as close to the primary source as possible in order to obtain the global reduction.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2009년도 춘계학술대회 논문집
• /
• pp.247-249
• /
• 2009

This paper investigates active noise control(ANC) of a rectangular cavity using single channel filtered-x least mean square(FXLMS) algorithms to reduce interior noise globally. To obtain global reduction of the interior noise, multichannel active control should be incorporated in general. We, however, examined firstly the optimal location of the secondary speaker that produces a global reduction of the interior noise field. We then investigated the frequency characteristics of the reduction to yield the effective frequency band of the active control system. It follows that the secondary speaker should be located as close to the primary source as possible in order to obtain global reduction.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 춘계학술대회논문집
• /
• pp.305-344
• /
• 2008

This paper presents the active control of flexible beam vibration. The beam was excited by a steady-state point force by mini shaker and the control was performed by mini shaker. To perform active control, least-mean-square (LMS) algorithm was used because it can easily obtain the complex transfer function in real-time. So an adaptive controller based on Filtered-X LMS algorithm was used and the controller was defined by minimizing the square of the response at a location of error sensor. In order to fine out performance tendency, input amplitude was changed in several cases and active vibration control was performed.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집B
• /
• pp.641-645
• /
• 2001

In this paper, it is discussed that active noise control in a circular duct using smart foam. Firstly, it is demonstrated that the potential of the conventional smart foam, proposed by Fuller, for active noise control in a duct. Conventional smart foam is not applicable to active noise control in a duct having flow. Thus, this paper presents a ring-type smart foam as an alternative. The ring-type smart foam consists of polyurethane acoustic foam of lining shape and PVDF film embedded in the foam. The embedded PVDF element acts as an actuator to reduce noise at lower frequencies and the foam absorbs noise at higher frequencies. A filtered-x LMS controller is used to minimize the signal from the error microphone. Experiments are executed to reduce broadband and tonal noise.

• 대한본초학회지
• /
• 제24권2호
• /
• pp.7-11
• /
• 2009

Objectives : This research was investigated anticoagulant effect of the Chaenomelis Fructus extract. Methods : To examine an active effect of anticoagulation in Chaenomelis Fructus extract, the study measured Prothrombin time(PT) and activated partial thromboplastin time (APTT) of human plasma in vitro and measured bleeding time and arterio-venous shunt model in rats in vivo. Results : Bleeding time of Chaenomelis Fructus extract in vivo had a significant increase as about 1.6 times and thrombus weight of Chaenomelis Fructus extract had a significant reduction of thrombus weight as 50%. Chaenomelis Fructus extract represented an effect of anticoagulation by operating on extrinsic pathway factor II, V, VII, X and intrinsic pathway factor VIII, IX, X, XI, XII in the coagulation system. Conclusions : Considering the above mentioned results, it is judged that a Chaenomelis Fructus extract has a control effect of thrombus creation.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1998년도 추계학술대회 논문집
• /
• pp.25-28
• /
• 1998

Lithiated cobalt and nickel oxides are becoming very attractive as active cathode materials for secondary lithium ion secondary battery. $LiCoO_2$ is easily synthesized from lithium cobalt salts, but has a relatively high oxidizing potential on charge. LiNiOz is synthesized by a more complex procedure and its nonstoichiometry significantly degraded the charge-discharge characteristics. But $LiNiO_2$ has a lower charge potential which increases the system stability. Lithiated cobalt and nickel oxides are iso-structure which make the preparation of solid solutions of $LiNi_{1-x}Co_xO_2$ for O$LiCoO_2 and LiNiO_2$ electrode. The aim of the presentb paper is to study the electrochemical behaviour, as weU as the possibilities for practical application of layered Iithiated nickel oxide stabilized by $Co^{3+}$ substitution as active cathode materials in lithium ion secondary battery.

• 한국멀티미디어학회논문지
• /
• 제16권7호
• /
• pp.829-840
• /
• 2013

본 논문은 흉부 X-선 기반으로 전역적 특성을 고려한 1차 영역 분할과 지역적 특성을 고려한 2차 영역 분할을 결합한 폐 영역 분할 방법을 제안한다. 1차 영역 분할은 랜드마크 기반의 학습 데이터를 사용하여 생성한 모델을 기반으로 일정 형태를 유지하며 경계선을 탐색하는 능동 형태 모델을 적용하였다. 2차 영역 분할은 국부 영역에 대하여 에너지를 산출하고 에너지가 최소가 되는 윤곽선을 탐색하는 국부 영역 기반 윤곽 모델을 사용하였다. 마지막으로 정확도를 평가하기 위해 5장의 영상을 전문가가 수동으로 분할한 영역과 제안한 방법을 통해 분할된 영역의 결과에 대한 다이스 계수를 계산하였으며, 유사도는 $95.33%{\pm}0.93%$로 나타났다. 효과적인 영상 분할 방법은 흉부 x-ray 영상에서 더 정확한 초기 진단과 예후 추정을 위한 컴퓨터 보조 진단 시스템의 개발에 필수적인 요소가 될 것으로 기대한다.

• 한국군사과학기술학회지
• /
• 제24권4호
• /
• pp.357-367
• /
• 2021

This paper studies the simulations of active airframe vibration controls for the Sikorsky X2 helicopter with a lift-offset coaxial rotor. The 4P hub vibratory loads of the X2TD rotor are obtained from the previous work using a rotorcraft comprehensive analysis code, CAMRAD II. The finite element analysis software, MSC.NASTRAN, is used to model the structural dynamics of the X2TD airframe and to analyze the 4P vibration responses of the airframe. A simulation study using Active Vibration Control System(AVCS) with Fx-LMS algorithm to reduce the airframe vibrations is conducted. The present AVCS is modeled using MATLAB Simulink. When AVCS is applied to the X2TD airframe at 250 knots, the 4P longitudinal and vertical vibration responses at the specified airframe positions, such as the pilot seat, co-pilot seat, engine deck, and prop gearbox, are reduced by 30.65 ~ 94.12 %.

• 한국전기전자재료학회논문지
• /
• 제30권8호
• /
• pp.474-478
• /
• 2017

We report on thin-film transistors based on $TiO_x$ pre-annealed by femtosecond laser pulses. A 30-nm thick $TiO_x$ active channel layer was initially deposited by an ALD system. The $TiO_x$ semiconducting films were annealed by irradiation with a femtosecond laser (power: $3W/cm^2$) for 5, 25, and 50s. Atomic force microscopy images revealed that the surface of a $TiO_x$ film without femtosecond laser pre-annealing was relatively rough, while after annealing with femtosecond laser pulses, the surface of the $TiO_x$ films became smooth. With increasing radiation time, the surrounding gas atmosphere could have a larger impact on the $TiO_x$ surface; meanwhile, the thin-film roughness decreased. Thin-film transistors with $TiO_x$ active channels pre-annealed at 50s exhibited good transfer characteristics and an on-to-off current ratio of ${\sim}10^3$.