• Title/Summary/Keyword: Temperature Stabilizing

Search Result 123, Processing Time 0.037 seconds

Study on Current Limiting Characteristics of YBCO Thin-Film Wire with Insulation Layer

  • Doo, Seung-Gyu;Du, Ho-Ik;Jeon, An-Gyoon
    • Transactions on Electrical and Electronic Materials
    • /
    • v.14 no.1
    • /
    • pp.20-23
    • /
    • 2013
  • When applying superconducting wire to power machines, an investigation needs to be carried out on the characteristics of wire phase changes in connection with the insulating layer. This study examined trends in the increase of the wire's resistance and the characteristics of its recovery from quenching by a current-applied cycle at temperatures of 90 K, 180 K, and 250 K. The procedure was conducted based on the thickness and presence (or absence) of the insulating wire layers. To achieve this, YBCO thin-film wires with the same critical temperatures were prepared with copper and stainless steel stabilizing layers. At levels (-one, three, and five-), with superior performance, polyimide pressure-sensitive adhesive tape was attached to the wires at a very low temperature. The eight prepared test samples were wound around the linear frames. The wire's voltage and current created from the phase change characteristics were measured at the wire's prescribed temperature, using the four-point probe method. The wire's resistance and recovery characteristics were examined for each cycle at temperatures of 90 K, 180 K, and 250 K.

Protective Effect of Biological Osmolytes against Heat- and Chaotropic Agent-Induced Denaturation of Bacillus licheniformis γ-Glutamyl Transpeptidase

  • Lo, Huei-Fen;Chi, Meng-Chun;Lin, Min-Guan;Lan, Yuan-Gin;Wang, Tzu-Fan;Lin, Long-Liu
    • Journal of Microbiology and Biotechnology
    • /
    • v.28 no.9
    • /
    • pp.1457-1466
    • /
    • 2018
  • In the present study, the stabilizing effect of four different biological osmolytes on Bacillus licheniformis ${\gamma}$-glutamyl transpeptidase (BlGGT) was investigated. BlGGT appeared to be stable under temperatures below $40^{\circ}C$, but the enzyme retained less than 10% of its activity at $60^{\circ}C$. The tested osmolytes exhibited different degrees of effectiveness against temperature inactivation of BlGGT, and sucrose was found to be the most effective among these. The use of circular dichroism spectroscopy for studying the secondary structure of BlGGT revealed that the temperature-induced conformational change of the protein molecule could be prevented by the osmolytes. Consistently, the molecular structure of the enzyme was essentially conserved by the osmolytes at elevated temperatures as monitored by fluorescence spectroscopy. Sucrose was further observed to counteract guanidine hydrochloride (GdnHCl)-and urea-induced denaturation of BlGGT. Taken together, we observed evidently that some well-known biological osmolytes, especially sucrose, make a dominant contribution to the structural stabilization of BlGTT.

An Experimental Study on the Temperature Control For a Gas Engine Cogeneration System (가스엔진 열병합시스템의 온도제어에 관한 실험적 연구)

  • 장상준;유재석;방효선;한정옥
    • Journal of Energy Engineering
    • /
    • v.5 no.1
    • /
    • pp.28-33
    • /
    • 1996
  • This study was carried out find out the appropriate tuning method of PID controller for a package type gas engine cogeneration system in terms of stabilizing the engine coolant temperature and system heat balance. In order to acquire the proper parameters of the controller, a system transfer function was set as a first order plus dead time model and thereafter model parameters were determined by using several tuning methods. And, with determined values of parameters and the system transfer functions, optimal turning method was selected by simulating the process using MATLAB. From the experimental results, it was found that obtained PID gains made the system stable in various operating conditions.

  • PDF

Smectic Layer Reorientation Induced by AC Field

  • Song, Jun-Ho;Kim, Yong-Bae;Kumar, Satyendra;Souk, Jun-Hyung;Shin, Sung-Tae
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2002.08a
    • /
    • pp.415-418
    • /
    • 2002
  • We have studied electro-optic properties and layer deformations in the smectic phases of 4-(6ethoxy-l-trifluoromethyl-hexyloxycarbonyl)-phenyl-4-Nonyloxybiphenyl-4-carboxylat ( TFMEOHPNBC ) having fluorine attached to one of its benzene rings by electro-optical and small angle x-ray scattering techniques. 3 and 5${\mu}m$ thick test cells were prepared using beryllium plates to minimize x-ray beam absorption. Layer structure and orientation was studied while changing the amplitude and frequency of the applied electric field as a function of cell temperature. We observed that the chevron layer tilt angle is reduced and layer spacing is increased as stabilizing in antiferroelectric phase. This result is extraordinary that there is dimerization in antiferroelectric phase. We also found that there is a threshold electric field that changes the chevron structure to bookshelf structure. This threshold electric field depends on the frequency and temperature as shown in Fig.1. We will discuss the dynamics of layer orientation as determined from the x-ray, electro-optic and dielectric spectroscopy.

  • PDF

Microstructures and Mechanical Properties of Ti-20Mo-0.5EB Composites (Hydroxyapatite를 대체하여 말뼈를 첨가한 Ti-20Mo-0.5EB의 미세조직과 기계적 특성)

  • Bae, Suhyun;Jeong, Wonki;Shin, Se-Eun
    • Journal of Powder Materials
    • /
    • v.28 no.5
    • /
    • pp.403-409
    • /
    • 2021
  • In this study, Ti-Mo-EB composites are prepared by ball milling and spark plasma sintering (SPS) to obtain a low elastic modulus and high strength and to evaluate the microstructure and mechanical properties as a function of the process conditions. As the milling time and sintering temperature increased, Mo, as a β-Ti stabilizing element, diffused, and the microstructure of β-Ti increased. In addition, the size of the observed phase was small, so the modulus and hardness of α-Ti and β-Ti were measured using nanoindentation equipment. In both phases, as the milling time and sintering temperature increased, the modulus of elasticity decreased, and the hardness increased. After 12 h of milling, the specimen sintered at 1000℃ showed the lowest values of modulus of elasticity of 117.52 and 101.46 GPa for α-Ti and β-Ti, respectively, confirming that the values are lower compared to the that in previously reported studies.

SPICE-Compatible Modeling of a Microbolometer Package Including Thermoelectric Cooler (열전 냉각기를 포함하는 볼로미터 패키지의 SPICE 등가 모델링)

  • Han, Chang Suk;Park, Seung Man;Kim, Nam-Hwan;Han, Seungoh
    • Journal of Sensor Science and Technology
    • /
    • v.22 no.1
    • /
    • pp.44-48
    • /
    • 2013
  • For a successful commercialization of microbolometer, it is required to develop a robust package including thermal stabilizing mechanism. In order to regulate the temperature within some operating range, thermoelectric cooler is generally used but it's not easy to model the whole package due to the coupled physics nature of thermoelectric cooler. In this paper, SPICE-compatible modeling methodology of a microbolometer package is presented, whose steady-state results matched well with FEM results at the maximum difference of 5.95%. Although the time constant difference was considerable as 15.7%, it can be offset by the quite short simulation time compared to FEM simulation. The developed model was also proven to be useful for designing the thermal stabilizer through parametric and transient analyses under the various working conditions.

Phase Stability Region of BiSrCaCuO Superconduction Thin Films Fabricated by Ion Beam Sputtering Method (이온 빔 스퍼터법으로 제작한 BiSrCaCuO 초전도 박막의 상안정 영역)

  • Yang, Sung-Ho;Park, No-Bong;Park, Yong-Pil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2003.05d
    • /
    • pp.49-52
    • /
    • 2003
  • BiSrCaCuO superconducting thin films have been fabricated by co-deposition using IBS(Ion Beam Sputtering) method. Despite setting the composition of thin film Bi2212 or Bi2223, in both cased, Bi2201, Bi2212 and Bi2223 phase were appeared. It was confirmed the obtained field of stabilizing phase was represented in the diagonal direction of the right below end in the Arrhenius plot of temperature of the substrate and $PO_3$ and it was distributed in the reeone.

  • PDF

Application of Biosurfactant(Sophorolipid) Produced from Candida bombiocola (Candida bombiocola로 부터 생산된 미생물 계면활성제(Sophorolipid)의 응용에 관한 연구)

  • 김원경;김은기
    • KSBB Journal
    • /
    • v.7 no.2
    • /
    • pp.107-111
    • /
    • 1992
  • Chayacterlstics of the sophorolipid produced from Candida bombiocola were investigated as an emulsifier of oil, a detergent or as a dispersant. Improved emulsification of crude oil was observed at high temperature ($70^{\circ}C$) with less than 1% concentration. Sophorolipid solution produced little foam even at reduced surface tension, however performance as a detergent of soiled cloths was poor. Dispersing and stabilizing abilities of sophorolipid solution were proved to be superior to those of chemical dispersants when examined by dispersing $Fe_2O_3$ or carbon black powders.

  • PDF

Study on Performance Characteristic of Water-Cooled Type Beat Pump Using Hydrocarbon Refrigerants (탄화수소계 냉매를 이용한 수냉식 히트점프의 성능특성에 관한 연구)

  • Jun Chul-Ho;Lee Ho-Saeng;Kim Jae-Dol;Yoon Jung-ln
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.29 no.8
    • /
    • pp.870-876
    • /
    • 2005
  • This study of the performance characteristics of natural refrigerants such as R-290 (propane), R-6OOa (iso-butane) and R-1270 (propylene) has investigated to compare with conventional HCFC's refrigerant R-22 for water-cooled heat pump system. The experimental apparatus has basic parts of cycle that uses the water as a heat source. The Performance of the water-cooled system using hydrocarbon refrigerants had been getting better than R-22 from start-up to the similar evaporating temperature after stabilizing system. Through the above it is possible that hydrocarbon refrigerants could be drop-in alternatives for R-22.

Numerical Simulation of Shock Wave Propagation using the Finite Difference Lattice Boltzmann Method

  • Kang, Ho-Keun;Michihisa Tsutahara;Ro, Ki-Deok;Lee, Young-Ho
    • Journal of Mechanical Science and Technology
    • /
    • v.16 no.10
    • /
    • pp.1327-1335
    • /
    • 2002
  • The shock wave process represents an abrupt change in fluid properties, in which finite variations in pressure, temperature, and density occur over the shock thickness which is comparable to the mean free path of the gas molecules involved. This shock wave fluid phenomenon is simulated by using the finite difference lattice Boltzmann method (FDLBM). In this paper, a new model is proposed using the lattice BGK compressible fluid model in FDLBM for the purpose of speeding up the calculation as well as stabilizing the numerical scheme. The numerical results of the proposed model show good agreement with the theoretical predictions.