• Title/Summary/Keyword: experimental device

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Development of Small Flat Plate Type Cooling Device (소형의 평판형 냉각장치 개발)

  • Moon, Seok-Hwan;Hwang, Gunn;Kang, Seung-Youl;Cho, Kyoung-Ik
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.22 no.9
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    • pp.614-619
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    • 2010
  • Recently, a problem related to the thermal management in portable electronic and telecommunication devices is becoming issued. That is due to the trend of a slimness of the devices, so it is not easy to find the optimal thermal management solution for the devices. From now on, a pressed circular type cooling device has been mainly used, however the cooling device with thin thickness is becoming needed by the inner space constraint of the applications. In the present study, the silicon flat plate type cooling device with the separated vapor and liquid flow path was designed and fabricated. The normal isothermal characteristics created by vapor-liquid phase change was confirmed through the experimental study. The cooling device with 70 mm of total length showed 6.8 W of the heat transfer rate within the range of $4{\sim}5^{\circ}C/W$ of thermal resistance. In the future, it will be possible to develop the commercialized cooling device by revising the fabrication process and enhancing the thermal performance of the silicon and glass cooling device.

Experimental Investigation of the Electrostatic Discharge(ESD) Damage in Packaged Semiconductor Devices (패키지 반도체소자의 ESD 손상에 대한 실험적 연구)

  • Kim, Sang-Ryull;Kim, Doo-Hyun;Kang, Dong-Kyu
    • Journal of the Korean Society of Safety
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    • v.17 no.4
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    • pp.94-100
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    • 2002
  • As the use of automatic handling equipment for sensitive semiconductor devices is rapidly increased, manufacturers of electronic components and equipments need to be more alert to the problem of electrostatic discharges(ESD). In order to analyze damage characteristics of semiconductor device damaged by ESD, this study adopts a new charged-device model(CDM), field-induced charged model(FCDM) simulator that is suitable for rapid, routine testing of semiconductor devices and provides a fast and inexpensive test that faithfully represents ESD hazards in plants. High voltage applied to the device under test is raised by the field of non-contacting electrodes in the FCDM simulator, which avoids premature device stressing and permits a faster test cycle. Discharge current and time are measured and calculated. The characteristics of electrostatic attenuation of domestic semiconductor devices are investigated to evaluate the ESD phenomena in the semiconductors. Also, the field charging mechanism, the device thresholds and failure modes are investigated and analyzed. The damaged devices obtained in the simulator are analyzed and evaluated by SEM. The results obtained in this paper can be used to prevent semiconductor devices form ESD hazards and be a foundation of research area and industry relevant to ESD phenomena.

Device Suitability Analysis by Comparing Performance of SiC MOSFET and GaN Transistor in Induction Heating System (유도 가열 시스템에서 SiC MOSFET과 GaN Transistor의 성능 비교를 통한 소자 적합성 분석)

  • Cha, Kwang-Hyung;Ju, Chang-Tae;Min, Sung-Soo;Kim, Rae-Young
    • The Transactions of the Korean Institute of Power Electronics
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    • v.25 no.3
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    • pp.204-212
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    • 2020
  • In this study, device suitability analysis is performed by comparing the performance of SiC MOSFET and GaN Transistor, which are WBG power semiconductor devices in the induction heating (IH) system. WBG devices have the advantages of low conduction resistance, switching losses, and fast switching due to their excellent physical properties, which can achieve high output power and efficiency in IH systems. In this study, SiC and GaN are applied to a general half-bridge series resonant converter topology to compare the conduction loss, switching loss, reverse conduction loss, and thermal performance of the device in consideration of device characteristics and circuit conditions. On this basis, device suitability in the IH system is analyzed. A half-bridge series resonant converter prototype using the SiC and GaN of a 650-V rating is constructed to verify device suitability through performance comparison and verified through an experimental comparison of power loss and thermal performance.

Development of a Bath Assistive System with Water Temperature Monitoring to Prevent Heart Attack (수온 모니터링 기능을 탑재한 심장마비 방지용 목욕 보조 시스템)

  • Kang, So Myoung;Wei, Qun
    • Journal of Korea Multimedia Society
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    • v.22 no.2
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    • pp.242-249
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    • 2019
  • Old people and patients with cardiovascular disease could die of a heart attack in the bath with heated water for a long time. Various researches have been studied to prevent these accidents from happening such as measuring the ECG signal when taking bath. However, these devices are hard to use and the higher price is not easily accepted by the public. In this paper, a low-cost and use-friendly, real time high precision water temperature monitoring device to prevent heart attack in the bath was developed. The device with waterproof design that lets the device can float on the surface of the water, and an accurate way to make water temperature measurement method was proposed by this paper that is immerging the sensor into water with 4cm depth to measure the temperature of underwater. The manufactured device was conducted to two experiments; one was to verify the basic functions of the device, and another one was for compare the proposed device with commercial products for monitoring the water temperature in the bathtub. As the experimental results shown, the proposed device has stable performance for the water temperature measurement and communicating with laptop in wireless.

An Experimental Study on the Design of Dobby Hook for Repeated Loading Force (반복하중을 받는 Dobby Hook의 설계에 관한 실험적 연구)

  • Kim, Jong-Su;Lee, Gyu-Jeong;Lee, Tae-Se
    • 한국기계연구소 소보
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    • s.20
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    • pp.115-118
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    • 1990
  • Hook of Dobby is a important part of shedding device, which must be endured the repeated loading force. In this paper, experiment on various mechanical characteristics; measurement of loading force were carried out, and compared the experimental values with results of Finite Element Method.

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Experimental and numerical studies of concrete bridge decks using ultra high-performance concrete and reinforced concrete

  • Shemirani, Alireza Bagher
    • Computers and Concrete
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    • v.29 no.6
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    • pp.407-418
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    • 2022
  • This paper numerically investigates the effect of changes in the mechanical properties (displacement, strain, and stress) of the ultra-high-performance concrete (UHPC) without rebar and the reinforced concrete (RC) using steel re-bars. This reinforced concrete is mostly used in the concrete bridge decks. A mixture of sand, gravel, cement, water, steel fiber, superplasticizer, and micro silica was used to fabricate UHPC specimens. The extended finite element method as used in the ABAQUS software is applied for considering the mechanical properties of UHPC, RC, and ordinary concrete specimens. To calibrate the ABAQUS, some experimental tests have been carried out in the laboratory to measure the direct tensile strength of UHPC by the compressive-to-tensile load converting (CTLC) device. This device contains a concrete specimen and is mounted on a universal tensile testing apparatus. In the experiments, three types of mixed concrete were used for UHPC specimens. The tensile strength of these specimens ranges from 9.24 to 11.4 MPa, which is relatively high compared with ordinary concrete specimens, which have a tensile strength ranging from 2 to 5 MPa. In the experimental tests, the UHPC specimen of size 150×60×190 mm with a central hole of 75 mm (in diameter)×60 mm (in thickness) was specially made in the laboratory, and its direct tensile strength was measured by the CTLC device. However, the numerical simulation results for the tensile strength and failure mechanism of the UHPC were very close to those measured experimentally. From comparing the numerical and experimental results obtained in this study, it has been concluded that UHPC can be effectively used for bridge decks.

Construction and Evaluation of an Experimental Type Torque Converter by Adapting an Electrorheological Fluid as an Operating Medium (전기유변유체를 동작매체로 하는 실험용 토크 전달장치 제작 및 성능평가)

  • 김상국;정동운;최윤대
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.10
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    • pp.2706-2711
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    • 1994
  • In this work, an experimental type of torque converter has been constructed and its characteristics have been evaluated by adapting an electrorheological fluid(ERF) as an operating medium. The device was designed by using the equations which were proposed by Carlson et al. The correlation between the rheological behaviour of an ERF and mechanical parameters of the clutch has been investigated. The torque generated by an ERF in this device is sum of one due to the yield strength by polarizing dispersed particles in dielectric oil and one due to the viscous drag. The experimental results are presented in terms of torque and current density as a function of rotational speed at various electric field strength applied. Experimental results showed that the measured torque was rapidly increased with the increase of the electric field, generally being proportional to the rotational speed of the motor. The measured current was shown to be increased with the increased electric field. Also, the current was decreased with the increase of increased with the increased electric field. Also, the current was decreased with the increase of the rotational speed of the motor and reached plateau region after f = 5 Hz.

Experimental and numerical investigation of expanded metal tube absorber under axial impact loading

  • Nouri, M. Damghani;Hatami, H.;Jahromi, A. Ghodsbin
    • Structural Engineering and Mechanics
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    • v.54 no.6
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    • pp.1245-1266
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    • 2015
  • In this research, the cylindrical absorber made of expanded metal sheets under impact loading has been examined. Expanded metal sheets due to their low weight, effective collapse mechanism has a high energy absorption capacity. Two types of absorbers with different cells angle were examined. First, the absorber with cell angle ${\alpha}=0$ and then the absorber with angle cell ${\alpha}=90$. Experimental Study is done by drop Hammer device and numerical investigation is done by finite element of ABAQUS software. The output of device is acceleration-time Diagram which is shown by Accelerometer that is located on the picky mass. Also the output of ABAQUS software is shown by force-displacement diagram. In this research, the numerical and experimental study of the collapse type, force-displacement diagrams and effective parameters has been investigated. Similarly, the comparison between numerical and experimental results has been observed that these results are matched well with each other. From the obtained results it was observed that the absorber with cell angle ${\alpha}=0$, have symmetric collapse and had high energy absorption capacity but the absorber with cell angle ${\alpha}=90$, had global buckling and the energy absorption value was not suitable.

Effectiveness of Beam-propagation-method Simulations for the Directional Coupling of Guided Modes Evaluated by Fabricating Silica Optical-waveguide Devices (광도파로 모드 간의 방향성 결합현상에 대한 빔 진행 기법 설계의 효율성 및 실리카 광도파로 소자 제작을 통한 평가)

  • Jin, Jinung;Chun, Kwon-Wook;Lee, Eun-Su;Oh, Min-Cheol
    • Korean Journal of Optics and Photonics
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    • v.33 no.4
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    • pp.137-145
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    • 2022
  • A directional coupler device, one of the fundamental components of photonic integrated circuits, distributes optical power by evanescent field coupling between two adjacent optical waveguides. In this paper, the design process for manufacturing a directional coupler device is reviewed, and the accuracy of the design results, as seen from the characteristics of the actual fabricated device, is confirmed. When designing a directional coupler device through a two-dimensional (2D) beam-propagation-method (BPM) simulation, an optical structure is converted to a two-dimensional planar structure through the effective index method. After fabricating the directional coupler device array, the characteristics are measured. To supplement the 2D-BPM results that are different from the experimental results, a 3D-BPM simulation is performed. Although 3D-BPM simulation requires more computational resources, the simulation result is closer to the experimental results. Furthermore, the waveguide core refractive index used in 3D-BPM is adjusted to produce a simulation result consistent with the experimental results. The proposed design procedure enables accurate design of directional coupler devices, predicting the experimental results based on 3D-BPM.