• Title/Summary/Keyword: Internal Power

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ESD damage mechanism of CMOS DRAM internal circuit and improvement of input protection circuit (정전기에 의한 CMOS DRAM 내부 회오의 파괴 Mechanism과 입력 보호 회로의 개선)

  • 이호재;오춘식
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.12
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    • pp.64-70
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    • 1994
  • In this paper, we inverstigated how a parricular internal inverter circuit, which is located far from the input protection in CMOS DRAM, can be easily damaged by external ESD stress, while the protection circuit remains intact. It is shown in a mega bit DRAM that the internal circuit can be safe from ESD by simply improving the input protection circuit. An inverter, which consists of a relatively small NMOSFET and a very large PMOSFET, is used to speed up DRAMs, and the small NMOSFET is vulnerable to ESD in case that the discharge current beyond the protection flows through the inverter to Vss or Vcc power lines on chip. This internal circuit damage can not be detected by only measuring input leakage currents, but by comparing the standby and on operating current before and after ESD stressing. It was esperimentally proven that the placement of parasitic bipolar transistor between input pad and power supply is very effective for ESD immunity.

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Modeling of Stochastic Properties of Internal Heat Generation of an Office Building for Slab Cooling Storage (사무소건물의 슬래브축냉을 위한 내부발열부하의 확률적 성상 모델화)

  • Jung, Jae-Hoon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.23 no.12
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    • pp.836-842
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    • 2011
  • It has been shown that the air-conditioning system with slab cooling storage is effective in cutting peak load and utilizing nighttime electric power. The stochastic properties of internal heat generation which has great influence on the cooling load are examined in this paper. Based on the measured cooling load and electric power consumption in an office building with slab cooling storage, stochastic time series models to simulate these random processes are investigated. Furthermore, a calculated result by an optimal control method of thermal analysis taking into account the internal heat is compared with the measured cooling load.

An Evaluation of the Effect of Internal Thinning Defect on the Failure Pressure of Elbow (곡관의 손상압력에 미치는 내부 감육결함의 영향 평가)

  • Kim, Jin-Weon;Kim, Tae-Soon;Park, Chi-Yong
    • Journal of the Korean Society of Safety
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    • v.18 no.4
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    • pp.28-34
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    • 2003
  • In the present study, three-dimensional finite element analysis was performed to investigate the effects of internal wall thinning defect on the failure pressure of elbow in the piping system and to develop the failure pressure evaluation model. From the results of finite element analysis, the failure pressure was derived by employing local stress criteria, and the effects of thinning location, bend radius, and defect geometry on the failure pressure of internally wall thinned elbow were investigated. Also, based on these investigations and previous model developed to estimate the failure pressure of elbow with an external pitting defect, the failure pressure evaluation model to be applicable to the elbow containing an internal thinning defect was proposed and compared with the results of finite element analysis. The failure pressure calculated by the model agreed well with the results of finite element analysis.

A Study on Optimal Control of Slab Cooling Storage Considering Stochastic Properties of Internal Heat Generation (내부발열의 확률적 성상을 고려한 슬래브축냉의 최적제어)

  • Jung, Jae-Hoon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.6
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    • pp.313-320
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    • 2015
  • In this paper, a method to obtain the probability distribution of room temperature and cooling load is presented, when the internal heat generation is applied to the system as a disturbance in the air conditioning system with slab cooling storage. The probability distribution of room temperature and the cooling load due to the disturbance were examined in one room of an office building. When considering only the electric power consumption as a probability component, it was found that the effect on room temperature and cooling load is small, because the probability component of the measured electric power consumption in the building is small. On the other hand, when considering the stochastic fluctuations of electric power consumption together with the heat generated by human bodies, the mean value of the cooling load was about 2,300 W and the ratio of the standard deviations was 19% (10 o'clock in second day). It was revealed that the stochastic effects of internal heat generation acting on the air conditioning system with slab cooling storage are not small.

Assessment of Internal Dose by $^3H\;&\;^{14}C$ of Total Diet for Inhabitants near Wolsung Nuclear Power Plants

  • Park, G.;Lin, X.J.;Kim, W.;Kang, H.D.;Doh, S.H.;Kim, D.S.;Kim, C.K.
    • Journal of Radiation Protection and Research
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    • v.28 no.1
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    • pp.51-57
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    • 2003
  • To assess the internal dose by $^3H\;&\;^{14}C$ in total diet of inhabitants near Wolsung Nuclear Power Plants, TFWT, OBT and $^{14}C$ concentration in total diet was analyzed for collection region and time. TFWT, OBT and $^{14}C$ concentrations were in the range of 3.19-42.2 Bq/L, 1.00-39.4 Bq/L, and 0.230-0.855 Bq/gC, respectively. The calculated annual effective dose with TFWT, OBT and $^{14}C$ is $6.10{\times}10^{-5}mSv/y,\;3.71{\times}10^{-5}mSv/y\;and\;7.08{\times}10^{-3}mSv/y$, respectively. And then annual internal dose with total diet for inhabitants near Wolsung NPPs is about $7.18{\times}10^{-3}mSv/y$, which is about 0.72% of annual effective dose limit 1 mSv/y.

Analysis and Experiment Verification of Heat Generation Factor of High Power 18650 Lithium-ion Cell (고출력 18650 리튬이온 배터리의 발열인자 해석 및 실험적 검증)

  • Kang, Taewoo;Yoo, Kisoo;Kim, Jonghoon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.24 no.5
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    • pp.365-371
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    • 2019
  • This study shows the feasibility of the parameter of the 1st RC parallel equivalent circuit as a factor of the heat generation of lithium-ion cell. The internal resistance of a lithium-ion cell consists of ohmic and polarization resistances. The internal resistances at various SOCs of the lithium-ion cell are obtained via an electrical characteristic test. The internal resistance is inversely obtained through the amount of heat generated during the experiment. By comparing the resistances obtained using the two methods, the summation of ohmic and polarization resistances is identified as the heating factor of lithium-ion battery. Finally, the amounts of heat generated from the 2C, 3C, and 4C-rate discharge experiments and the COMSOL multiphysics simulation using the summation of ohmic and polarization resistances as the heating parameter are compared. The comparison shows the feasibility of the electrical parameters of the 1st RC parallel equivalent circuit as the heating factor.

Stability Analysis of an Asymmetric Shaft with Internal Damping (내부감쇠가 있는 축비대칭 구동축의 안정성 해석)

  • Shin, Eung-Soo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.1
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    • pp.8-14
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    • 2013
  • This paper intends to provide the whirling characteristics of an asymmetric rotor-shaft system with a non-ideal DC motor. The equations of motion have been derived in terms of system parameters such as the internal/external damping, the asymmetry and the motor voltage. By imposing the conditions that the motor input power should be balanced by the dissipated power, steadystate whirling characteristics are obtained such as the whirling amplitude, the whirling frequency and the stability diagrams. Results show that the whirling stability is affected by the internal/external damping and the asymmetry as well as the motor voltage. Also, the whirling amplitude at the steadystate is increased and the motor speed is lowered as the internal damping becomes higher or the external damping is reduced. In addition, the asymmetry causes the variation of the whirling orbit, which becomes splitted into two distinct trajectories. Finally, non-ideal characteristics of the DC motor is found to reduce the whirling motion in case of steadystate whirling with high asymmetry and high internal damping.

Performance analysis of a R744 and R404A cascade refrigeration system with internal heat exchanger (내부 열교환기 부착 R744-R404A용 캐스케이드 냉동시스템의 성능 분석)

  • Oh, H.K.;Son, C.H.
    • Journal of Power System Engineering
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    • v.16 no.1
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    • pp.38-43
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    • 2012
  • This paper describes an analysis on performance of R744-R404A cascade refrigeration system with internal heat exchanger to optimize the design for the operating parameters of the system. The operating parameters considered in this study include subcooling and superheating degree, internal heat exchanger and compression efficiency, evaporating and condensing temperature in the R744 low- and R404A high-temperature cycle and temperature difference of cascade heat exchanger. The main results are summarized as follows : COP of cascade refrigeration system increases with the increasing of compression efficiency, but decreases with the increasing temperature difference of cascade heat exchanger. Also, the COP increases with the increasing of internal heat exchanger efficiency in high-temperature cycle, but decreases with that in low-temperature cycle. Therefore, internal heat exchanger efficiency, compressor efficiency and temperature difference of cascade heat exchanger on R744-R404A cascade refrigeration system have an effect on the COP of this system.

The Effect of Internal Marketing on Apparal Firms' Performance (의류업체에서 내부 마케팅의 영향 요인이 내부 성과와 외부 성과에 미치는 영향)

  • Row Young;Park Jae-Ok;Lee Kyu-Hye
    • The Research Journal of the Costume Culture
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    • v.13 no.3 s.56
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    • pp.452-468
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    • 2005
  • The major aim of this study was to find factors that effectively improve the satisfaction of apparel firms' employees who are the internal customer and how these factors affect customer satisfaction. The subjects of the study was salespeople working at major women's apparel retail outlets and their customers located in Seoul. A data from 192 questionnaire were used for the final analysis. Descriptive statistics, factorial analysis, Cronbach's a, Person's correlation coefficient, and multiple regression were conducted. The results indicated that factors influenced by internal marketing were recruitmenteducation training, power endorsement, internal communication, CEO's management style and human resource management Regression analysis results indicated that recruitmenteducation training and power endorsement significantly influenced internal performance of the organization (employee's commitment to and satisfaction with the organization). Employee's commitment significantly influenced external performance of the organization, consumer satisfaction where as employees' satisfaction with the organization did not have significant effect.

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