• 한국축산시설환경학회지
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• 제21권3호
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• pp.105-112
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• 2015

This study was conducted to establish the research direction of heat stress in dairy cows by searching papers and patents. Research papers published before 2014 through National Digital Science Library (NDSL) and patents registered with United States Patent and Trademark Office (USPTO), Japan Patent Office (JPO), European Patent Office (EPO) and Korean Intellectual Property Office (KIPO) were investigated using the key words of heat stress index, genetics, facilities and feed. The research trend for heat stress in dairy cows was analyzed with 182 papers and 282 patents. Global warming due to increased atmospheric concentration of greenhouse gases is a major interest in recent years. The papers related with heat stress in cattle were increased after 2006. Besides, patents connected with facilities and feed will be increased due to development of ICT. In particular, the various studies including patents about heat stress in dairy cows will be needed to conduct because the climate of southern Korean peninsula is changing from temperate to subtropic.

• 접착 및 계면
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• 제14권1호
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• pp.28-35
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• 2013

본 연구에서는 표면처리된 Ga-doped ZnO (GZO)를 사용해서 태양열 차단 코팅제를 제조하였으며, 표면처리 화합물의 종류와 처리조건에 따른 입자의 분산성, 가시광선투과율, 자외선차단율, 적외선차단율, 단열특성 등에 대해서 고찰하였다. IPA나 아크릴 바인더를 사용했을 때에는 무기산화물 입자의 분산특성이 낮았으나, 무기산화물 입자를 우레탄(우레아)기와 아크릴기 그리고 실리카를 포함하는 하이브리드 화합물로 표면처리한 경우에는 입자의 분산성이 향상되어 침전되는 입자가 거의 발생되지 않았고 가시광선 투과율과 헤이즈(haze)가 크게 향상되었다. 그리고 실제 단열특성을 평가하기 위해서 단열평가 장치와 sunlamp를 사용하였으며, 평가결과 열차단 필름을 사용한 경우 PET 필름 자체만 사용했을 때와 비교해서 내부온도가 $4.8^{\circ}C$ 이상 낮은 것으로 확인되었다.

• 한국염색가공학회지
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• 제20권6호
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• pp.87-91
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• 2008

It is commonly known that water repellency of the fabric treated with fluorocarbon resin brings about a decrease by the washing and recovers by the subsequent heat treatment. In this article, effect of the water repellency was investigated on the nylon 6, triacetate and silk fabrics treated with hydrocarbon and silicon resins. Hydrocarbon and silicon resins have been widely used in the textile finishing as the softening and water proofing agents. The fabrics were treated with hydrocarbon resins, Paragium JQ and RC (Ohara Paragium Chemical Co.) and a silicon resin, Poron MR (Shinetsu Chemical Co.), and then washed and subsequently heat treated. Although the water repellency increased by the resin treatment, it decreased by the washing apparently and recovered a little by the heat treatment. The effect of the heat treatment was small comparing with that of the fluorocarbon resin. Furthermore, as a mechanical property of the treated fabric, KES shearing and bending hysteresis parameters, modulus and hysteresis width of the hydrocarbon resin-treated nylon 6, triacetate and silk fabrics decreased by the heat treatment after washing. Therefore, the treatment is effective at improving the softening of the fabric in water repellent finish.

• 센서학회지
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• 제32권1호
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• pp.39-43
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• 2023

Microscale thermophysical property measurements of liquids have been developed considering the increasing interest in the thermal management of cooling systems and energy storage/transportation systems. To accurately predict the heat transfer performance, information on the thermal conductivity, heat capacity, and density is required. However, a simultaneous analysis of the thermophysical properties of small-volume liquids has rarely been considered. Recently, we proposed a new methodology to simultaneously analyze the aforementioned three intrinsic properties using heater-integrated fluidic resonators (HFRs) in an atmospheric pressure environment comprising a microchannel, resistive heater/thermometer, and mechanical resonator. Typically, the thermal conductivity and volumetric heat capacity are measured based on a temperature response resulting from heating using a resistive thermometer, and the specific heat capacity can be obtained from the volumetric heat capacity by using a resonance densitometer. In this study, we analyze methods to improve the thermophysical property measurement performance using HFRs, focusing on the effect of the ambience around the sensor. The analytical method is validated using a numerical analysis, whose results agree well with preliminary experimental results. In a vacuum environment, the thermal conductivity measurement performance is enhanced, except for the thermal conductivity range of most gases, and the sensitivity of the specific heat capacity measurement is enhanced owing to an increase in the time constant.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.173-176
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• 2009

A great emphasis has been placed on the design of heat treatment process to achieve desired microstructure and mechanical property of final product. In this study, finite element analysis was carried out to predict temperature, microstructure and hardness of eutectoid steel after water quenching. Convective heat transfer coefficients were determined by inverse analysis using surface temperatures measured with three different installation methods of thermocouples. Finally, the effect of convective heat transfer coefficients on the prediction of temperature history and hardness was analyzed by comparing experimental and simulation results.

• Journal of Welding and Joining
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• 제33권5호
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• pp.31-34
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• 2015

Microstructure and tensile property in the weld heat-affected zone (HAZ) of austenitic Fe-Mn-Al-C low density steels were investigated through transmission electron microscopy analysis and tensile tests. The HAZ samples were prepared using Gleeble simulation with high heat input welding condition of 300 kJ/cm, and the HAZ peak temperature of $1200^{\circ}C$ was determined from differential scanning calorimetry (DSC) test. The strain- stress responses of base steels showed that the addition of V improved the tensile and yield strength by grain refinement and precipitation strengthening. Tensile strength and elongation decreased in the weld HAZ as compared to the base steel, due to grain growth, while V-added steel had a higher HAZ strength as compared than V-free steel.

• 열처리공학회지
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• 제14권6호
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• pp.323-329
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• 2001

Artificial aging was performed to simulate the microstructural degradation in 2.25CrMo steel arising from long time exposure at $540^{\circ}C$. The carbide morphologies were classified as acicular, pipe and globular type, and the number of carbides per unit area was measured for each type of carbides. The fine acicular carbides were found to diminish drastically in the initial stage of aging. An attempt was made to evaluate the microstructural degradation in artificially aging heat treated 2.25CrMo steel by the magnetic property measurements such as saturation magnetization, coercivity and remanence. The saturation magnetization showed no distinct trend with aging time. However, the coercivity and remanence were observed to decrease rapidly in initial 920 hours of aging time and then decrease slowly afterwards.

• Journal of Magnetics
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• 제18권3호
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• pp.348-351
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• 2013

Inconel 600 alloy, Ni base alloy, is widely used for steam generator tubings where sensitization occurs at grain boundaries and sensitization will induce tubing failures. This alloy has usually paramagnetic property, however, it transforms into ferromagnetic property along grain boundaries when sensitization occurs: this means NDE using magnetism for sensitization is possible. Therefore, in this study, Inconel 600 alloys were heat treated at 873 K from 0 to 400 hours so as to generate sensitization and their magnetic properties were investigated in detail. The saturation and the residual magnetization increase with increasing heat treatment time and take a maximum. On the other hand, the coercive force decreases with the increase in time of heat treatment. We confirmed that characteristics at only grain boundaries change into ferromagnetic phase by a MFM observation. As a trial for industrial application, heat treated Inconel 600 alloy was scanned by a magnetic field sensor, and the variations in magnetization were obtained nondestructively. The results indicate a feasibility of magnetic NDE for sensitization of Inconel 600 alloy.

• 세라미스트
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• 제21권2호
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• pp.83-88
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• 2018

There is close relation between the heat generation and the performance of electronic device. The durability and efficiency of the device are degraded due to heat generation. It is necessary to release the generated heat from an electronic device. Based on demands of the printed circuit board (PCB) manufacturing, the robust and reliable plating technique of PCB is necessary. In this study, we review various methods for improving the heat sink property. These methods were considered to enhance the adhesion between ceramic substrate as heat sink and metal layer as electrode.

• 소성∙가공
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• 제19권1호
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• pp.25-31
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• 2010

To achieve desired microstructure and mechanical property of a manufacturing product, heat treatment process is applied as a secondary process after forging. Especially, quenching process is used for improving strength, hardness, and wear resistance since phase transformation occurs owing to rapid heat transfer from the surface of the specimen. In the present paper, a study on surface temperature measurement for water quenching of eutectoid steel was investigated. In order to determine the temperature history in experiments, three different measuring schemes were used by varying installation techniques of K-type thermocouples. Depending on the measured temperature distribution at the surface of the specimen, convective heat transfer coefficients were numerically determined as a function of temperature by the inverse finite element analysis considering the latent heat generation due to phase transformation. Based on the inversely determined convective heat transfer coefficient, temperature, phase, and hardness distributions in the specimen after water quenching were numerically predicted. By comparing the experimental and computational hardness distribution at three different locations in the specimen, the best temperature measuring scheme was determined. This work clearly demonstrates the effect of temperature measurement on the final mechanical property in terms of hardness distribution.