• 수산해양기술연구
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• 제53권3호
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• pp.302-307
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• 2017

An electric steam boiler equipped with a condensate recovery system, which stores the condensate generated after using steam in steam washers, steam cookers, steam irons, and steam cleaners in a condensate tank and supplies compressed air to the condensate tank so that the condensate is recovered to the boiler by the pressure of the compressed air, was studied. In the results of this study, the heat energy balance between the quantity of the heat generated by the non-metallic surface heating element and the quantity of the heat absorbed by the water was good in a range of ${\pm}5%$. In addition, the heat transfer rate increased in proportion to the electric power of the surface heating element heater, the waste heat energy was normally recovered by the recovery of the condensate of the steam boiler equipped with the high compression waste heat recovery system, and the recovery rate of the waste heat exhibited 23%.

• 대한기계학회논문집B
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• 제40권2호
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• pp.69-73
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• 2016

최근 자동차 엔지니어들은 자동차 엔진의 열효율을 향상시키기 위한 수단으로 폐열 회수 기술에 많은 관심을 기울이고 있다. 배기량이 큰 가솔린 엔진은 대체로 V형인데, 열 회수를 위해 두 개의 슈퍼히터를 각각의 배기 다기관 가까이에 설치하는 것은 비용 면에서 효율적이지 않다. 하나의 슈퍼히터를 한쪽 배기 다기관에 최대한 가깝게 부착하면 좀 더 높은 열교환 효율을 얻을 수 있으나 폐열회수를 위한 배기가스의 유량은 절반이 된다. 반면에, 배기가스의 유량을 전부 이용하기 위하여 두 배기관이 합류된 지점에 슈퍼히터를 설치하면 배기가스의 온도는 많이 감소된다. 이 사실을 바탕으로 슈퍼히터의 최적 위치를 조사하기 위하여 상용프로그램인 AMESim을 이용해 해석을 수행하였다. 이 때, 배기가스 유량 중 절반만을 사용하더라도 슈퍼히터를 배기 다기관과 최대한 가까이 부착하는 것이 엔진의 배기가스로부터 3.8 kW의 열을 더 회수할 수 있는 것으로 나타났다. 이 결과를 바탕으로 최적의 폐열 회수 모델을 도출하고 제안하였다.

• 한국의류학회지
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• 제15권2호
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• pp.199-209
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• 1991

In this paper, the fabrics for Korean folk clothes(KFC) undergoes repeated laundering under given condition. After this cyclic laundering was applied, the mechanical properties of the specimen were measured using KES-F system in order to evaluated the end-use performance of fabrics for KFC. And also, the crease recovery of fabrics for KFC were measured by shirley crease recovery tester. 78 different kinds of commercial silk fabrics and polyester fabrics for KFC were used for this study. The experimental results were analysed statistically to relate the mechanical properties and the crease recovery of fabrics for KFC. Furthermore, these changes in dimensional stability, mechanical properties and handle of fabrics for KFC were discussed in comparison with those values for silk fabrics and polyester fabrics. The results obtained are as follows. 1. Regardless of materials, remarkable increase are observed in shrinkage of the fabrics for KFC about repeated laundering, but dull increase are observed in shrinkage after 10 cycles of the repeated laundering. On the other hand, slack extend are observed in dimensions after 20 cycles of the repeated laundering. The shrinkage of fabrics for KFC after 10 cycles of the lundering showed that the silk fabrics are $1.74{\pm}0.33\%$ (warp direction) and $1.35{\pm}0.23\%$ (weft direction) and the polyester fabrics are $1.45{\pm}0.22\%$ (warp direction) and $1.25{\pm}0.23\%$ (weft direction). 2. Except for tensile property, these changes in mechanical properties of fabrics for KFC by laundering have $\pm$ 16 range of bending, shearing, compression, surface, thickness & weight as compared with before laundering. Particularly, the LT and RT about $1\~3$ cycles of the repeated laundering showed remarkable decrease. And SMD, WC, T & W of fabrics for KFC by the laundering were more increased than one for original fabrics. But B, 2HB, G, 2HG, 2HGS were decreased more than one for original fabrics. 3. 'Stiffness', 'Anti-drape', 'Crispness' and 'Scroop' hand values decrease and'Fullness & softness', 'Flexibility & softness' hand values increase with repeated laundering. 4. Remarkable decrease are observed in crease recoveries about $1\~5$ cycles of the repeated lundering, but slack decrease are observed in crease recoveries after 5 cycles of repeated laundering. The crease recovery of fabrics for KFC have negative(-) correlation with LT, RT, G, RC and MMD, This fact implies that the smaller these values, the larger the crease recovery. The crease recovery of fabrics for KFC has a high degree of correlation with the mechanical properties such as shearing, compression, surface property. And also, the crease recovery are expected by measuring the mechanical properties such as G, 2HG, 2HGS, RC, WC, LC, MIU, MMD and SMD, according to the obtained regression equation.

• 설비공학논문집
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• 제20권7호
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• pp.492-499
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• 2008

The cooling load in winter is significant in many commercial buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. The development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the performance of a multi-heat pump with 3-piping system was investigated as a function of refrigerant charge and its performance was analyzed in cooling mode, heating mode, and heat recovery mode. COP in the heating or cooling mode showed little dependence on refrigerant charge at overcharge conditions, while those were strongly dependent on refrigerant charge at undercharge conditions and outdoor inlet temperature. In the heat recovery mode, the performance of the system was very sensitive to charge amount at all conditions. Optimum charge amount in the heat recovery mode was 14% lower than that in the cooling mode at the standard condition because the refrigerant only passed the indoor units. It is required to store the excessive refrigerant charge in a storage tank to optimize the system performance at operating modes.

• 한국자동차공학회논문집
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• 제20권2호
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• pp.78-84
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• 2012

The purpose of this study is to investigate the performance characteristics of new exhaust heat recovery device for the engine's fast warm-up. In this study, two different interior area designed for prototyping and on the exhaust heat recovery device to evaluate the performance compare the performance characteristics were chosen a better product. A company's product and selected prototype-2 were evaluated and compared the performance. This experiment was conducted under the same conditions. The time from starting to warm-up of engine was measured. As a result, the performance characteristics of the prototype-2 was not higher than that of the A company's product. However, in comparison with base system, prototype-2 of the exhaust heat recovery device discover that the warm-up time was shortened.

• 한국정보전자통신기술학회논문지
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• 제13권2호
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• pp.113-122
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• 2020

Noise affects the accuracy of three-dimensional shape recovery. Its occurrence is unpredictable and depends on several mechanical, environmental, and other factors. When two-dimensional image sequences are obtained for shape from focus (SFF), mechanical vibration occurs in the translational stage, causing an error in the three-dimensional shape recovery. To address this issue, mechanical vibration is modeled using Newton's second law and the principle of the rack and pinion gear. Then, an optimal sampling step size considering the mechanical vibration is suggested through theoretical demonstration. Experiments conducted with real objects verify the effectiveness of the proposed sampling step size. In this paper, in a realistic environment with noise, the potential of obtaining more accurate three-dimensional reconstruction results of the objects is explored by acquiring the optimal sampling step size, which improves the sampling step size relative to those reported in a previous study performed under similar conditions.

• Fibers and Polymers
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• 제7권4호
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• pp.328-332
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• 2006

Poly(ethylene terephthalate) (PET) and poly(ethylene glycol) (PEG) copolymers cross-linked with pentaerythritol, a four-way cross-linker, are prepared to compare their mechanical and shape memory properties with the one cross-linked by glycerol. Composition of PEG and pentaerythritol is varied to search for the one with the best mechanical and shape memory properties. The highest shape recovery rate is observed for the copolymer composed of 30 mol% PEG-200 and 2.5 mol% pentaerythritol. Four-way cross-linking by pentaerythritol significantly improves shape recovery rate and retention of high shape recovery rate after repeated use compared to the one cross-linked by glycerol, a three-way cross-linker, and difference and advantage of additional cross-linking point are discussed.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1272-1276
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• 2009

The purpose of this study is to introduce wasted heat recovery heat exchanger for different kind of material in HVAC systems in field. For the purpose of estimating the large volume rotary heat exchanger and cross flow plate heat exchanger in heat recovery ventilator.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1613-1618
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• 2004

Diffuser is an important fluid-mechanical equipment to convert kinetic energy into pressure energy. Many of the experimental and theoretical researches have been done in a diffuser but the understanding of energy transfer and detailed mechanism of energy dissipation is unclear. In this study, computations were performed using a numerical method with SIMPLE algorithm for conical diffuser with various diffuser angles and diffuser lengths. Also, we investigated the pressure recovery coefficient in conical diffuser by inserting strut. In this paper, we showed that the strut can cause a rising pressure recovery.

• Journal of Korean Neurosurgical Society
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• 제49권2호
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• pp.83-91
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• 2011

Objective : Minocycline, a second-generation tetracycline-class antibiotic, has been well established to exert a neuroprotective effect in animal models and neurodegenerative disease through the inhibition of microglia. Here, we investigated the effects of minocycline on motor recovery and neuropathic pain in a rat model of spinal cord injury. Methods : To simulate spinal cord injury, the rats' spinal cords were hemisected at the 10th thoracic level (T10). Minocycline was injected intraperitoneally, and was administered 30 minutes prior surgery and every second postoperative day until sacrifice 28 days after surgery. Motor recovery was assessed via the Basso-Beattie-Bresnahan test Mechanical hyperalgesia was measured throughout the 28-day post -operative course via the von Frey test Microglial and astrocyte activation was assessed by immunohistochemical staining for ionized calcium binding adaptor molecule 1 (lba1) and glial fibrillary acidic protein (GFAP) at two sites: at the level of hemisection and at the 5th lumbar level (L5). Results : In rats, spinal cord hemisection reduced locomotor function and induced a mechanical hyperalgesia of the ipsilateral hind limb. The expression of lba1 and GFAP was also increased in the dorsal and ventral horns of the spinal cord at the site of hemisection and at the L5 level. Intraperitoneal injection of minocycline facilitated overall motor recovery and attenuated mechanical hyperalgesia. The expression of lba1 and GFAP in the spinal cord was also reduced in rats treated with minocycline. Conclusion : By inhibiting microglia and astrocyte activation, minocycline may facilitate motor recovery and attenuate mechanical hyperalgesia in individuals with spinal cord injuries.