• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.10
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• pp.1598-1602
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• 2004

In this paper, we report a microthermostat using PDMS (poly-dimethylsiloxane) and glass. This PDMS/glass chip is able to maintain constant temperature that is necessary for restriction enzyme reaction. Since PDMS is the low-cost and the mass-producible material and has very good biochemical compatibility, PDMS chip has more benefit than general Si chip. Heater was made of Au wiring patterned on Pyrex glass. A reaction chamber has a capacity of about 3 ${mu}ell$. We performed a restriction enzyme reaction by using the fabricated microthermostat and conventional method. Then, with the electrophoresis, we made a comparison between the result from the micro reactor and the one from conventional method.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.324-331
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• 2013

All evacuated tube collector is being constantly studied since it can reduce the conductive heat loss in absorber by using vacuum technology and has advantage of heat transport capacity and quick thermal response in comparatively small temperature difference. This study investigated the dynamic thermal performance of the solar collector with the control condition of solar irradiance and fluid temperature by using performance experimental apparatus which is combined with solar collector and refrigerator, examined the thermal characteristics in definite temperature range of fluid in constant temperature tank by simultaneously measuring refrigerating performance. As a result of it, I deducted the related equation of collector efficiency and found that mean collector efficiency has increased through quick heat transfer characteristics according to increase of outdoor temperature and irradiance in case of outlet temperature of constant temperature tank $22^{\circ}C$ when set outlet temperature of solar collector $25^{\circ}C$ with outlet temperature of constant temperature tank $18^{\circ}C$ & $22^{\circ}C$. Also COP of refrigerator was acquired value of 6.2~7.1 at outlet temperature of constant temperature tank $18^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2055_2056
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• 2009

국가표준을 유지하기위한 표준기급의 교류저항은 상품화된 것이 외국에서 한 종류 있으나 고정된 기름 항온조에서 유지를 해야 하고, 정전차폐가 어렵고, 교류에서 측정단자의 호환성이 어렵고 가격도 대단히 비싸다. 또한 저항체가 지지대 역할을 하는 원형 보빈에 감겨져있는 선으로 구성되어서 국제비교시나 혹은 이동교정시에 기계적인 구조의 변화로 저항 값에 영향을 받기가 쉽다. 이러한 단점들을 극복한 교류저항 표준기가 개발이 되었다. 개발된 표준기는 저항체의 기계적 구조에 의한 변화를 막기 위해서 non-inductive 구조의 metal foil element로 제작된 것을 사용하였으며, 각각의 저항체에 개개의 항온조를 체택함으로서 온도의 안정성과 이동의 편리를 함께 만족되도록 하였다. 제작된 교류저항 표준기의 특성은 온도 안정도가 ${\pm}5$ mK/d, 저항값의 안정도가 ${\pm}0.01{\mu}{\Omega}/{\Omega}/d$, 1년간의 장기안정도가 $1{\mu}{\Omega}/{\Omega}$ 이하로 측정이 되었다. 개발된 교류저항 표준기는 교류저항분야 국가표준유지 및 소급에 사용이 된다.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.10a
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• pp.90-91
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• 1996

투과증발은 일반 막공정과 달리 투과물의 상전이와 이로 인한 체류액의 온도강하가 존재하기 때문에 열전달현상을 간과할 수 없다. 즉 막을 통한 열전달이 다른 막공정에 비해 현저하게 차이가 난다는 것이다. 이러한 현상은 모듈의 길이가 짧거나 모듈을 항온조에 담가 수행하는 실험실 규모의 투과증발조업에서는 거의 발견되지 않는다. 그러나 투과증발장치가 커져 모듈의 항온유지가 블가능하고 사용되는 막도 상업화되어 투과속도가 비교적 큰 것을 사용하는 파일롯 규모의 실험에서는 쉽게 나타나는 현상이다. Rautenbach등이 셀룰로오즈 아세테이트 막을 이용한 물의 투과증발 실험에서 막간 온도강하가 5~12 K정도 일어났음을 보고한 바 있었다. 이때 온도강하는 조업조건에 따라 달라졌으며 유속이 낮을 수록 증가함을 보였다. 본 연구에서는 투과증발이 일어나는 모듈내에서 열전달현상을 열공급비를 정의하여 해석하였으며, 상전이 현상이 막분리효율에 끼치는 영향을 설명하였다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.4 no.1
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• pp.59-66
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• 1975

Silkworm and silkworm-chrysalis as an edible insect have been investigated. Through this investigation, the following results are obtained : 1) Silkworm and silkworm-chrysalis as a good source of protein-rich compound was examined, and they contained 54.9% to 56% protein as a crude protein. 2) Except tryptophan, almost all the essential amino acids contained. The amount of the amino acids was on the increased as much as the silkworm growth. 3) The following amino acids was not detected on the silkworm fibron analysis, aspartic acid, glutamic acid, cystine and methionine. But the following amino acid were relatively high amount : glycine, alanine, and tyrosine. 4) Sucrose, fructose, and glucose as a carbohydrates was investigated, the results are from 0.312% to 0.313% as an invert sugar; 0.289% to 0.305% as a glucose; 0.333% to 0.412% as a fructose. 5) The acidity and pH of the milk was examined according to the silkworm-chrysalis powder added. added material was not effected as far as the milk was change. Therefore, the milk and the silkworm-chrysalis mixture are being a good drinkable things.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.199-204
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• 2000

This paper reports a thermal environmental analysis of a room in accommodated with multi-heat sources according to ventilation condition. Two case modification have been investigated to obtain the lower temperature distribution in the room. The temperature distribution of the original room were found about $25{\sim}35^{\circ}C$. As a result, the use of, three ventilating fans and two electric fans are useful for room ventilation respectively, and using two electric fan is more recommendable in side of economical efficiency.

• KSBB Journal
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• v.8 no.4
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• pp.358-363
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• 1993

The effect of ultrasound on the acid hydrolysis of inulin was studied under significantly mild reaction conditions, at which sugar degradation products were not detected. Reaction conditions were i the range of 50~$60^{\circ}C$ and 0.1~0.3%(w/w) of HCl concentrations. The effects of reactor position inside water bath and mechanical agitation under ultrasound were investigated. The production rates of fructose with/without ultrasound irradiation were compared. The activation energies for both control and ultrasound reaction were the same, i. e., 25kca1/mo1, and ultrasound enhancement was average 22%.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.857-863
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• 1992

Acid type saturated Weston cells that can be used as the standard of electromotive force unit were constructed and their characteristics in a specially designed enclosure were evaluated. Cadmium sulfate was purified by recrystallization under vaccum. Mercurous sulfate with dispersed mercury and the exact composition of cadmium amalgam were obtained by means of electrolysis. The enclosure was constructed using a commercial circulator. Temperature of the enclosure was only drifted in the range of ${\pm}$5 mK in the case of extreme change of room temperature. The electromotive force of standard cells was measured over the temperature range of 5∼${\sim} 30^{\circ}C$. The standard deviation of the electromotive forces was about 1 ppm.

• Korean Journal of Materials Research
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• v.7 no.11
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• pp.942-950
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• 1997

NiAI기 산화물 분산강화(Oxide Dispersion Strengthende:ODS)합금을 기계적 합금화 (Mechanical Alloying: MA)방법으로 제조하였으며, 열간압축방법으로 성형하였다. 연이어 단순항온처리에 의한 정상결정립성장과 특성조건에서의 thermomechanical treatment 에 의한 이차재결정화를 유도하였다. 결정립 조대화된 ODSD MA NiAI의 creep 성질 및 이에 조대화된 미세조직은 creep 성질이 저하된 반면, 이차재결정화된 MA NiAI의 creep성질은 크게 향상되었다. 이 creep 성질의 향상은 이차재결정화의 특성인 급격한 결정립의 조대화, 분산상의 성장억제 및 grain aspect ratio의 증가에 기인한 것으로 사료되었다. 이차재결정화된 ODS MA NiAI의 creep또는 glide controlled dislocation creep임을 제시하지만, 전체 creep속도가 결정립 크기 및 grain aspect ratio의 영향을 크게 받은 것을 볼 때, 결정립계 미끄럼기구가 주 creep 기구와 조합되어 MA NiAI의 전체 creep기구에 영향을 준 것으로 추정할 수 있었다.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.1
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• pp.7-16
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• 1995

In countries where confucianism is popular, it is extremely hard to get fresh cadaver bone for allograft. Therefore in Korea, the reimplantation of resected autoclaved autogenous bone segments has been increasingly performed for limb reconstruction of extremities with malignancies. To preserve the bone morphogenetic protein and mechanical strength of heated bone, many studies have reported that pasteurization of bone is far better than autoclaving over $100^{\circ}C$. Based on this assumption, replacement with a pasteurized autogenous bone graft after resection of a malignant bone tumor was deemed feasible for reconstruction. However, little is known about how high a temperature and how much time for pasteurization is needed to make tumors completely necrotic and to maintain the mechanical strength of bone. Consequantly, experimental studies were carried out to test heat conductivity of human bone and torsional strength of porcine tibia after pasteurization. First, two pairs of human proximal tibia and distal femur were used. We used T-type thermocoples to check core temperature of the bone and a computerized data acquisition system to record results. Without reaming of the medullary cavity, in a $60^{\circ}C$-thermostatic saline tub, it took 32 minutes and 50 seconds to raise the core temperature of human proximal tibia from $20^{\circ}C$ to $58^{\circ}C$, and 30 minutes for distal femur. In a $80^{\circ}C$ saline tub, it took 12 minutes and 50 seconds for proximal tibia, and 11 minutes and 10 seconds for distal femur. In contrast, using porcine tibia whose cortical thickness is similar to that of human tibia, after reaming of the medullary canal, it took less than 3 minutes and 30 seconds in a $60^{\circ}C$ saline tub, less than 1 minute and 45 seconds in a $70^{\circ}C$ tub, and less than 1 minute in a $80^{\circ}C$ tub to elevate core temperature from $20^{\circ}C$ to $58^{\circ}C$. Second, based on data of the heat conductivity test, we compared the torsional strength before and after pasteurization. Twenty matched pairs of porcine tibia were used, The left one was used as a non-heated control group and the right one as a pasteurized experimental group. Wighout reaming of the medullary cavity, there was no statistical difference in torsional strength between the pasteurization of the $60^{\circ}C$-35minute and of $80^{\circ}C$-15minute. With reaming, we also found no statistical difference among pasteurization of $60^{\circ}C$-15 minute, of $70^{\circ}C$-15 minute, and of $80^{\circ}C$-15 minute groups. In conclusion, reaming of the medullary canal is very helpful in saving pasteurization time. And, in a $60^{\circ}C$ saline tub, no significant weakness in torsional strength occurs with pasteurization of the bone for up to 35 minutes. Also no significant weakness in torsional strength occurs with an exposure of 15 minutes to the $80^{\circ}C$ saline tub.