• Title/Summary/Keyword: Thermal switch

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Prototype of Smart Foundation with Heating Devices (발열장치를 이용한 기능성 스마트 파운데이션의 구성 시안)

  • Hwang, Young-Mi;Lee, Jeong-Ran
    • Fashion & Textile Research Journal
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    • v.14 no.4
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    • pp.588-596
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    • 2012
  • This research was intended to design an experimental girdle with thermal insulation function for adult women in their 20s. The design of the experimental girdle was based on the pattern of commercially available girdle. The final pattern of the experimental girdle was established according to the drawing equations determined based on the result of appearance evaluation. The equations were (waist circumference${\times}0.88$)/2 for waist circumference, (hip circumference${\times}0.77$)/2 for hip circumference, and (thigh circumference${\times}0.85$) for thigh circumference. In order to develop a heating device, the most effective fabric heater was adopted based on the experiments about the number of caron fibers, heater size and attachment site. Three heaters-one with a size of $14.5{\times}9.5$ cm, and the other two with the size of $8.0{\times}15.0$ cm-were attached to the areas corresponding to the lower abdomen and the hip, 5 cm below the waist. A heater was developed by connecting these heaters to a controller, 2 batteries (7.4 V 2000 mAh lithium polymer batteries) and a switch (for mode conversion between high/medium/low temperatures). The heater was integrated into the inside of the girdle, so that attachment and detachment were possible without the change of appearance. The tentative configuration plan was proposed for the development of a functional smart girdle with an excellent thermal insulation effect.

Unfolding of Ervatamin C in the Presence of Organic Solvents: Sequential Transitions of the Protein in the O-state

  • Sundd, Monica;Kundu, Suman;Dubey, Vikash Kumar;Jagannadham, Medicherla V.
    • BMB Reports
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    • v.37 no.5
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    • pp.586-596
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    • 2004
  • The folding of ervatamin C was investigated in the presence of various fluorinated and non-fluorinated organic solvents. The differences in the unfolding of the protein in the presence of various organic solvents and the stabilities of O-states were interpreted. At pH 2.0, non-fluorinated alkyl alcohols induced a switch from the native $\alpha$-helix to a $\beta$-sheet, contrary to the $\beta$-sheet to $\alpha$-helix conversion observed for many proteins. The magnitude of ellipticity at 215 nm, used as a measure of $\beta$-content, was found to be dependent on the concentration of the alcohol. Under similar conditions of pH, fluorinated alcohol enhanced the intrinsic a-helicity of the protein molecule, whereas the addition of acetonitrile reduced the helical content. Ervatamin C exhibited high stability towards GuHCl induced unfolding in different O-states. Whereas the thermal unfolding of O-states was non-cooperative, contrary to the cooperativity seen in the absence of the organic solvents under similar conditions. Moreover, the differential scanning calorimetry endotherms of the protein acquired at pH 2.0 were deconvoluted into two distinct peaks, suggesting two cooperative transitions. With increase in pH, the shape of the thermogram changed markedly to exhibit a major and a minor transition. The appearance of two distinct peaks in the DSC together with the non-cooperative thermal transition of the protein in O-states indicates that the molecular structure of ervatamin C consists of two domains with different stabilities.

Thermal Change Prediction of Magnetic Switch Using Regression Analysis (회귀 분석 기법을 활용한 전자 개폐기의 온도 변화예측)

  • Moon, Cheolhan;Yeon, Yeong-Mo;Kim, Seung-Hee;Min, Jun-Ki
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.6
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    • pp.749-755
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    • 2022
  • Electricity is essential energy in modern society, such as being used in various industries. However, the rate of fires occurring on electric wiring to deal with it is very high. In this work, we implemented a system to predict the temperature change of an electric circuit through analysis using various regression models. To do so, we collected the temperature data of 27 types of magnetic switches which control electric circuits as well as trained the regression models by using the collected temperature data. In our experiments, we confirmed that the regression models can be trained at a sufficiently usable level since the difference between the actual temperature and predicted temperature is about 4℃. The results of our work will be useful to predict the temperature of electric circuits and preventing fires on them.

Study on the Dynamic Synchronizing Control of An Islanded Microgrid (독립운전 마이크로그리드의 능동형 동기 투입 제어에 관한 연구)

  • Cho, Chang-Hee;Jeon, Jin-Hong;Kim, Jong-Yul;Kwon, Soon-Man;Kim, Sung-Shin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.6
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    • pp.1112-1121
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    • 2011
  • A microgrid is an aggregation of multiple distributed generators (DGs) such as renewable energy sources, conventional generators, and energy storage systems that provide both electric power and thermal energy. Generally, a microgrid operates in parallel with the main grid. However, there are cases in which a microgrid operates in islanded mode, or in a disconnected state. Islanded microgrid can change its operational mode to grid-connected operation by reconnection to the grid, which is referred to as synchronization. Generally, a single machine simply synchronizes with the grid using a synchronizer. However, the synchronization of microgrid that operate with multiple DGs and loads cannot be controlled by a traditional synchronizer, but needs to control multiple generators and energy storage systems in a coordinated way. This is not a simple job, considering that a microgrid consists of various power electronics-based DGs as well as alternator-based generators that produce power together. This paper introduces the results of research examining an active synchronizing control system that consists of the network-based coordinated control of multiple DGs. Consequently, it provides the microgrid with a deterministic and reliable reconnection to the grid. The proposed method is verified by using the test cases with the experimental setup of a microgrid pilot plant.

irrE, an Exogenous Gene from Deinococcus radiodurans, Improves the Growth of and Ethanol Production by a Zymomonas mobilis Strain Under Ethanol and Acid Stresses

  • Zhang, Ying;Ma, Ruiqiang;Zhao, Zhonglin;Zhou, Zhengfu;Lu, Wei;Zhang, Wei;Chen, Ming
    • Journal of Microbiology and Biotechnology
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    • v.20 no.7
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    • pp.1156-1162
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    • 2010
  • During ethanol fermentation, bacterial strains may encounter various stresses, such as ethanol and acid shock, which adversely affect cell viability and the production of ethanol. Therefore, ethanologenic strains that tolerate abiotic stresses are highly desirable. Bacteria of the genus Deinococcus are extremely resistant to ionizing radiation, ultraviolet light, and desiccation, and therefore constitute an important pool of extreme resistance genes. The irrE gene encodes a general switch responsible for the extreme radioresistance of D. radiodurans. Here, we present evidence that IrrE, acting as a global regulator, confers high stress tolerance to a Zymomonas mobilis strain. Expression of the gene protected Z. mobilis cells against ethanol, acid, osmotic, and thermal shocks. It also markedly improved cell viability, the expression levels and enzyme activities of pyruvate decarboxylase and alcohol dehydrogenase, and the production of ethanol under both ethanol and acid stresses. These data suggest that irrE is a potentially promising gene for improving the abiotic stress tolerance of ethanologenic bacterial strains.

Short-circuit Analysis of Solenoid and Pancake Type Bifilar Winding Magnets using BSCCO tape

  • Park Dong Keun;Ahn Min Cheol;Yang Seong Eun;Yoon Il Gu;Kim Young Jae;Ko Tae Kuk
    • Progress in Superconductivity and Cryogenics
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    • v.7 no.4
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    • pp.28-31
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    • 2005
  • To verify the feasibility of bifilar winding type superconducting fault current limiter (SFCL) using BSCCO tape, two types of magnets were fabricated and tested by short-circuit in this research. Even if the FCL using high Tc superconducting (HTS) tape has zero resistance in normal state, it needs to be wound as a bifilar winding for zero inductance. Solenoid type and pancake type bifilar winding magnets are designed and fabricated with the same length of BSCCO tape. The test system consists of AC power supply, transformer, fault switch, load and bifilar winding magnet. The applied AC voltages during fault duration, 0.1s, were from 0.5V to 20V. The test results without bifilar winding magnet were compared with those with each type magnets. The test results include voltage against magnet, transport current and generated resistance curve. Thermal stability, the recovery time, was studied from the results of two type magnets. The pancake type was the most effective to limit fault current but the solenoid type was thermally the most stable. From this research, short-circuit characteristics of the two types were obtained.

Performance analysis of dual source heat pump system with single unit dual source evaporator (SUDS증발기를 사용한 2중열원 열펌프의 성능해석)

  • 우정선;이세균;이재효;박효순
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.3
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    • pp.391-400
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    • 1999
  • The efficiency and capacity of an air source heat pump system decrease as the ambient temperature drops. One strategy of avoiding the decrease of the efficiency and capacity in air source heat pump system is to switch to another thermal energy source. Water can be a good candidate for the heat source. This paper presents the results of the performance analysis of heat pump system with a single unit dual source(SUDS) evaporator The heat exchanger combines two separated evaporators into a single evaporator and the object of the SUDS evaporator is to recover energy from dual heat sources, i.e. air and water. Simulation program is developed for the dual source heat pump system with a SUDS evaporator and experimental data are obtained and compared with the simulation results. Differences in heating capacity and COP are 7% and 8% respectively. Simulation results are in good agreement with the test results. Therefore, the developed program is effectively used for the design and performance prediction of the dual source heat pump system with a SUDS evaporator.

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A Study on safety against a fire of charging cable for mobile phone for vehicle (자동차용 모바일 폰 충전 케이블의 발화 안전성에 관한 연구)

  • Kwon, Jin-Wook;Choi, Kyu-Sik;Hwang, Myung-Whan
    • Journal of the Korea Safety Management & Science
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    • v.20 no.3
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    • pp.21-26
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    • 2018
  • This paper describes result of a study on safety against a fire of charging cable for mobile phone for vehicle. Combustion on the USB cable in the car was happened while driving. Gas coming from the burning USB cable could be a reason which can make a secondary car accident since the driver also can be embarrassed while driving. In order to prevent a secondary car accident connected on the road, to research a reason why USB cable can emit gas and be burned in charging. We did simulation test with abnormal fault condition for the electronic component on the board in the USB cable. So we get the result from abnormal fault condition simulation test, for instance, shorted test for output terminal of 8 pin switch, shorted test for chip resistor after thermal aging in the condition $25^{\circ}C$, 93 % RH during 48 hours. To analysis the result of all test, Combustion on the USB cable was not the 8 pin but other electrical component such as a chip resistor. Therefore we guess that the reason for USB cable combustion in charging in a car was not 8 pin and a LED but another defective component.

A Study on the Manufacture of Gas Insulated Switchgear Spacer Using APG Molding Process (APG 주형방식을 이용한 가스절연개폐기용 절연 스페이서 제작에 관한 연구)

  • Lee, Chanyong;Bae, Jaesung;Cho, Han-Gu;Lee, Sangmook;Lee, Jaehyeong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.4
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    • pp.386-391
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    • 2022
  • The gas insulation switchgear, which is a device for protecting a power system, cannot be supported by the insulation gas itself in a charge unit stored in a metal container. Therefore, molding technology is required to manufacture a gas insulation switch spacer. The APG method injection molding simulation was performed by applying the variables obtained through the physical properties of an epoxy composite used for manufacturing an insulating spacer to a moldflow software. After varying the temperature conditions of heater in the simulation, the thermal characteristics and the degree of hardening of the spacer were analyzed, based on which the optimum process conditions are presented.

Fabrication and characterization of $WSi_2$ nanocrystals memory device with $SiO_2$ / $HfO_2$ / $Al_2O_3$ tunnel layer

  • Lee, Hyo-Jun;Lee, Dong-Uk;Kim, Eun-Kyu;Son, Jung-Woo;Cho, Won-Ju
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.134-134
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    • 2011
  • High-k dielectric materials such as $HfO_2$, $ZrO_2$ and $Al_2O_3$ increase gate capacitance and reduce gate leakage current in MOSFET structures. This behavior suggests that high-k materials will be promise candidates to substitute as a tunnel barrier. Furthermore, stack structure of low-k and high-k tunnel barrier named variable oxide thickness (VARIOT) is more efficient.[1] In this study, we fabricated the $WSi_2$ nanocrystals nonvolatile memory device with $SiO_2/HfO_2/Al_2O_3$ tunnel layer. The $WSi_2$ nano-floating gate capacitors were fabricated on p-type Si (100) wafers. After wafer cleaning, the phosphorus in-situ doped poly-Si layer with a thickness of 100 nm was deposited on isolated active region to confine source and drain. Then, on the gate region defined by using reactive ion etching, the barrier engineered multi-stack tunnel layers of $SiO_2/HfO_2/Al_2O_3$ (2 nm/1 nm/3 nm) were deposited the gate region on Si substrate by using atomic layer deposition. To fabricate $WSi_2$ nanocrystals, the ultrathin $WSi_2$ film with a thickness of 3-4 nm was deposited on the multi-stack tunnel layer by using direct current magnetron sputtering system [2]. Subsequently, the first post annealing process was carried out at $900^{\circ}C$ for 1 min by using rapid thermal annealing system in nitrogen gas ambient. The 15-nm-thick $SiO_2$ control layer was deposited by using ultra-high vacuum magnetron sputtering. For $SiO_2$ layer density, the second post annealing process was carried out at $900^{\circ}C$ for 30 seconds by using rapid thermal annealing system in nitrogen gas ambient. The aluminum gate electrodes of 200-nm thickness were formed by thermal evaporation. The electrical properties of devices were measured by using a HP 4156A precision semiconductor parameter analyzer with HP 41501A pulse generator, an Agillent 81104A 80MHz pulse/pattern generator and an Agillent E5250A low leakage switch mainframe. We will discuss the electrical properties for application next generation non-volatile memory device.

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