• 제목/요약/키워드: Temperature variation

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Study on variation of electrical characteristics of vertical PV module according to the change of irradiance and temperature (수직형 태양광발전모듈의 계절별 일사획득 및 온도변화에 따른 출력특성 변화에 관한 연구)

  • Park, Kyung-Eun;Kang, Gi-Hwan;Kim, Hyun-Il;Yu, Gwon-Jong;Kim, Jun-Tae
    • 한국태양에너지학회:학술대회논문집
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    • 2008.11a
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    • pp.57-62
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    • 2008
  • Building Integrated PV(BIPV) is one of the best fascinating PV application technologies. To apply PV module in building, various factors should be reflected such as installation position, shading, temperature, and so on. Especially the installation condition should be considered, for the generation performance of PV module is changed or the generation loss is appeared according to installation position, method, and etc. This study investigates variation of electrical characteristics of a PV module according to the change of irradiance and temperature. From this experimental study, we confirmed that the irradiance, the temperature variation and the generation performance of a PV module were appeared differently according seasonal variation. Actually the PV module installed in building facade showed high-generation performance in winter.

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Characterization of Thermal Expansion Coefficients of Carbon/Epoxy Composite for Temperature Variation (탄소섬유 복합재료의 온도변화에 대한 열팽창계수 특성 변화 규명)

  • 김주식;윤광준
    • Composites Research
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    • v.12 no.6
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    • pp.1-7
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    • 1999
  • The change of the coefficients of thermal expansion(CTE) of Carbon/Epoxy was investigated for the temperature variation and a prediction model for the change of CTE was proposed. Elastic properties and CTEs in the principal material directions were measured in the range of room temperature to cure temperature and characterized as functions of temperature. By applying the characterized properties to the classical lamination theory, a computational method to predict the change of CTEs of a general laminate for temperature variation was proposed. the coefficients of thermal expansion of laminates with various stacking sequences were measured and compared with those predicted. Good agreements between the predicted results and the experimental data show that the c hanges of CTEs of a general laminate for temperature variation can be predicted well by using the proposed method.

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A Study on the Temperature Variation Characteristics of Power VDMOSFET (전력 VDMOSFET의 온도변화 특성에 관한 연구)

  • Lee, Woo-Sun
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.35 no.7
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    • pp.278-284
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    • 1986
  • Double-diffused metal oxide power semiconductor field effect transistors are used extensively in recent years in various circuit applications. The temperature variation of the drain current at a fixed bias shows both positive and negative resistance characteristics depending on the gate threshold voltage and gate-to source bias votage. In this paper, the decision method of the gate crossover voltage by the temperature variation and a new method to determine the gate threshold voltage graphecally are presented.

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Temperature Effects in the Resistivity Monitoring at Embankment Dams (저수지 전기비저항 모니터링에서의 온도효과)

  • Kim, Eun-Mi;Cho, In-Ky;Kim, Ki-Seog;Yong, Hwan-Ho
    • Geophysics and Geophysical Exploration
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    • v.21 no.2
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    • pp.82-93
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    • 2018
  • Resistivity monitoring data at embankment dams are affected by the seasonal temperature variation. Especially when the seasonal temperature variation is large like Korea, the temperature effects may not be ignored in the longterm resistivity monitoring. Therefore, temperature effects can make it difficult to accurately interpret the resistivity monitoring data. In this study, through analyzing the time series of ground temperature collected at an embankment dam, ground temperature variations are calculated approximately. Then, based on the calculated temperature profile with depth, the inverted resistivity model of the embankment dam is corrected to remove the temperature effects. From these corrections, it was confirmed that the temperature effects are significant in the upper, superficial part of the dam, but can be ignored at depth. However, temperature correction based only on the temperature distribution in the dam body cannot remove the temperature effect thoroughly. To overcome this problem, the effect of temperature variation in the reservoir water seems to be incorporated together with the air temperature variation.

Dynamic Strength Variation of Glass Epoxy Composites with respect to Strain Rates (변형률 속도에 따른 유리섬유 에폭시 복합재료의 동적 강도 변화)

  • 임태성;이대길
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.05a
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    • pp.83-88
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    • 2001
  • In this study, the tensile and compressive tests of glass fiber epoxy composites were performed to measure the strength variation with respect to strain rates of 1-200 $\textrm{sec}^{-1}$. In addition, tensile and compressive tests of 50-200 $\textrm{sec}^{-1}$ strain rates were conducted at a low temperature ($-60^{\circ}C$) to investigate the effects of temperature on the strength variation. From the test results, it was found that the tensile and compressive strengths increased about 100% and 70%, respectively, at the strain rates of 10-100 $\textrm{sec}^{-1}$ compared to the quasi-static strengths while the strengths were little affected by the environmental temperature variation.

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Temperature Control of Ondol Indoor-Space (온돌 실내공간의 온도제어)

  • Shin, C.B.;Lee, J.W.;Sah, J.Y.;Lee, S.C.;Cho, S.H.;Suh, H.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.3
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    • pp.538-545
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    • 1995
  • The heat transfer model of ondol heating system is derived in the linear form. The step responses of On-Off controller, PID controller and Position type fuzzy controllers are compared in the sense of several aspects : variation of temperature feedback variable, variation of supplied heat quantity by the boiler, variation of flow rate, variation of thickness of the base, variation of the outdoor temperature.

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Thermal buckling of FGM beams having parabolic thickness variation and temperature dependent materials

  • Arioui, Othman;Belakhdar, Khalil;Kaci, Abdelhakim;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.27 no.6
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    • pp.777-788
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    • 2018
  • An investigation on the thermal buckling resistance of simply supported FGM beams having parabolic-concave thickness variation and temperature dependent material properties is presented in this paper. An analytical formulation based on the first order beam theory is derived and the governing differential equation of thermal stability is solved numerically using finite difference method. a function of thickness variation is introduced which controls the parabolic variation intensity of the beam thickness without changing its original material volume. The results showed the high importance of taking into account the temperature-dependent material properties in the thermal buckling analysis of such critical beam sections. Different Influencing parametric on the thermal stability are studied which may help in design guidelines of such complex structures.

Simulation of the hot water ONDOL heating system by response factor method (應答係數法에 의한 溫水 溫室 暖房 시스템의 Simulation)

  • 조상준;민만기;최영돈
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.3
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    • pp.409-424
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    • 1987
  • Simulation on the hot water ONDOL heating system was made in order to investigate the variation of room temperature and specific fuel consumption of boiler. Heat balance equation was derived by response factors and solved implicitly. Variation of room temperature and specific fuel consumption of boiler were calculated with respect to the thickness of room floor, the absorptivity of wall for solar radiation, on-off temperature range of boiler and air exchange. The results show that specific fuel consumption of boiler is independent of the thickness of room floor and decreases with increasing the absorptivity of wall and on-off temperature range of boiler. However, it increases with increasing the air exchange. They also show that, when the absorptivity and on-off temperature range of boiler are increased, the amplitudes of room temperature variation increase.

An Accurate Current Reference using Temperature and Process Compensation Current Mirror (온도 및 공정 보상 전류 미러를 이용한 정밀한 전류 레퍼런스)

  • Yang, Byung-Do
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.8
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    • pp.79-85
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    • 2009
  • In this paper, an accurate current reference using temperature and process compensation current mirror (TPC-CM) is proposed. The temperature independent reference current is generated by summing a proportional to absolute temperature (PTAT) current and a complementary to absolute temperature (CTAT) current. However, the temperature coefficient and magnitude of the reference current are influenced by the process variation. To calibrate the process variation, the proposed TPC-CM uses two binary weighted current mirrors which control the temperature coefficient and magnitude of the reference current. After the PTAT and CTAT current is measured, the switch codes of the TPC-CM is fixed in order that the magnitude of reference current is independent to temperature. And, the codes are stored in the non-volatile memory. In the simulation, the effect of the process variation is reduced to 0.52% from 19.7% after the calibration using a TPC-CM in chip-by-chip. A current reference chip is fabricated with a 3.3V 0.35um CMOS process. The measured calibrated reference current has 0.42% variation for $20^{\circ}$C${\sim}$100$^{\circ}$C.

Crack Initiation and Temperature Variation Effects on Self-sensing Impedance Responses of FRCCs (FRCCs의 자가센싱 임피던스 응답에 미치는 균열 발생 및 온도 변화 영향성)

  • Kang, Myung-Soo;Kang, Man-Sung;Lee, Han Ju;Yim, Hong Jae;An, Yun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.3
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    • pp.69-74
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    • 2018
  • Fiber-Reinforced Cementitious Composites (FRCCs) have electrical conductivity by inserting reinforced conductive fibers into a cementitious matrix. Such characteristic allows us to utilize FRCCs for crack monitoring of a structure by measuring electrical responses without sensor installation. However, the electrical responses are often sensitively altered by temperature variation as well as crack initiation. The temperature variation may disturb crack detection on the measured electrical responses. Moreover, as sensing probes for measuring electrical reponses increase, undesired contact noises are often augmented. In this paper, a self-sensing impedance circuit is specially designed for reducing the number of sensing probes. The crack initiation and temperature variation effects on the self-sensing impedance responses of FRCCs are experimentally investigated using the self-sensing impedance circuit. The experiment results reveal that the electrical impedance response are more sensitively changed due to temperature variation than crack initiation.