각-관 열교환기의 냉각능력 향상에 관한 연구

이대희,조헌노,원세열,이영민 인제대학교 1999 仁濟論叢 Vol.14 No.3

본 연구에서는 변압기 냉각용 각-관(Shell and Tube) 열교환기의 성능을 실험적으로 테스트하여 열교환기의 냉각능력을 향상시키는 기술을 개발하고자 하였다. 예열수조 2개를 항온조와 함께 사용함으로써 열교환기 입구에서와 온수의 초기온도를 60℃로 유지하고, cooling tower를 이용하여 입구에서 냉각수 온도를 20℃로 유지하였다. 냉각수 유량변화(5ℓ/min, 10ℓ/min, 15ℓ/min)에 따른 baffle의 형태(Single-segmental baffle, Double-segmental baffle, Disk & Doughnut baffle, Helical baffle)와 baffle의 개수(7개에서 5개) 및 tube의 개수(26개에서 18개)를 변화시켰을 때 열교환기의 냉각능력을 각각 실험하였다. 온수와 냉각수의 입ㆍ출구에서의 온도변화를 측정하기 위하여 Thermocouple을 온수와 냉각수 관의 입ㆍ출구에 하나씩 설치하였다. 실험결과 Disk & Doughnut, Helical baffle, Double-segmental baffle의 열전달률이 Single-segmental baffle보다 5.3%, 5.5%, 11.8% 높고, Double-segmental baffle의 경우 Tube 수의 감소율이 35%일 때 열전달률의 감소율은 14.3%임을 알 수 있었고, baffle의 수가 5개에서 7개로 증가했을 때 열전달률이 12.1% 증가함을 알았다. An experimental study to enhance the cooling capacity of the shell and tube type heat exchanger has been carried out. The initial temperature of hot water in the heat exchanger is maintained at 60℃, using two preheating water baths and one constant temperature water bath, while the coolant temperature is maintained at 20℃ by way of the cooling tower. For the coolant rates of 5 ℓ/min, 10 ℓ/min, 15 ℓ/min, the experiments to determine the heat exchanger cooling capacity have been performed using the various types of baffle(Single- segmental baffle, Double-segmental baffle, Disk & Doughnut baffle, Helical baffle), the number of baffles(from 7 to 5) and number of tubes(from 26 to 18). Thermocouples are installed in the inlet and outlet of hot-water and coolant tube to measure the temperature difference. It was found that the heat transfer rates for Disk & Doughnut baffle, Helical baffle, Double-segmental baffle are 5.3%, 5.5%, 11.8% higher than the Single-segmental baffle, respectively. When the number of tube is reduce by 35%, the 14.3% decrease in the heat transfer rate occurs, while when the number of baffle increases from 5 to 7, the 12% increase in the heat transfer rate occurs.

Antioxidant Activity and Whitening Effect of Lindera erythrocarpa Extract

Min ?Chul Kang,Ryeo Kyeoung Ko,Ju-Yeop Lee,Haeng-Bum Kim,Bong-Seok Kim,Jong-Heon Han,Seong-Hyun An,Gi-Ok Kim 한국생물공학회 2008 한국생물공학회 학술대회 Vol.2008 No.10

Totally Laparoscopic Pancreaticoduodenectomy Using 3D Flexible Laparoscopic System

( Heon Tak Ha ),( Ja Ryung Han ),( Hyung Jun Kwon ),( Jae Min Chun ),( Sang-geol Kim ),( Yoon Jin Hwang ),( Young Seok Han ) 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: Robotic PD has not yet been expanded due to the needs of the dedicated teams and the excessive costs. 3D flexible laparoscopic system (3D) with depth perception and spatial orientation allows the precise dissection of the dangerous site and facilitate the comfortable reconstruction. We present experiences regarding the efficacy of L-PD using 3D. Methods: Totally L-PD was attempted in 15 patients from June 2016 to June 2017. However, conversion to open PD was required in one patient with tumor invasion to the superior mesenteric vein. Pancreaticojejunostomy was completed with the dunking procedure in 1 patient and with duct-to-mucosa technique in 13 patients. Results: Mean operation time was 500 min. The replaced right hepatic artery originated from superior mesenteric artery of hepatic artery was identified in one patient and preserved well because of the precise dissection under the excellent visual field. The mean size of pancreatic duct and hepatic duct were 3 mm and 10 mm. There was no major intra-operative complications and post-operative mortality. Postoperative complications were detected in 7 patients, including pancreatic fistula (n=5), and delayed gastric emptying (n=2). All pancreatic fistula was grade A and were recovered with conservative treatment. Conclusions: In selected patients, L-PD is a safe and effective procedure with comparable surgical outcomes to open surgery. Especially, we believe that 3D will play an important role in the expansion of complicated PD surgery and will provide a bridge role for future robot systems.

Effects of Supercritical Carbon Dioxide Treatment on Meat Quality and Sensory Evaluation in Soy Sauce and Hot-pepper Paste Marinated Pork

Young Min Choi,Sang Hoon Lee,Jee Hwan Choe,Kyoung Heon Kim,Min Suk Rhee,Byoung Chul Kim 한국축산식품학회 2013 한국축산식품학회지 Vol.33 No.5

The objective of this study was to investigate the effects of supercritical carbon dioxide (SC-CO2) treatment on meat quality and sensory evaluation of marinated pork. Meat marinated in two traditional Korean marinades, soy sauce and hot-pepper paste, and raw marinated meat were then treated with 7.4, 12.2, or 15.2 MPa CO2 at 31.1oC for 10 min. The SC-CO2 treatments had no effect on the meat pH (p>0.05) or Warner-Bratzler shear force (p>0.05). There was no significant difference (p>0.05) in the total loss (sum of treatment loss and cooking loss) between the control and SC-CO2 treated samples at 15.2 MPa (soy sauce marinated pork: 21.78 vs. 18.97%; hot-pepper marinated pork: 21.61 vs. 18.01%). After the SC-CO2 treatment, lighter surface colors were observed in the treatment samples compared to those of the control samples (p< 0.001). However, tasting panelists were unable to distinguish a difference in color or in overall acceptability of the control and treatment (p>0.05). In the case of soy sauce marinated pork, when SC-CO2 applied at 15.2 MPa and 31.1oC for 10 min, treatment samples showed a tenderer meat than the control samples. Therefore, the SC-CO2 treatment conditions had no adverse effects on the sensory quality characteristics of the marinated meat products.

Effects of Supercritical Carbon Dioxide Treatment on Meat Quality and Sensory Evaluation in Soy Sauce and Hot-pepper Paste Marinated Pork

Choi, Young Min,Lee, Sang Hoon,Choe, Jee Hwan,Kim, Kyoung Heon,Rhee, Min Suk,Kim, Byoung Chul Korean Society for Food Science of Animal Resource 2013 한국축산식품학회지 Vol.33 No.5

The objective of this study was to investigate the effects of supercritical carbon dioxide (SC-$CO_2$) treatment on meat quality and sensory evaluation of marinated pork. Meat marinated in two traditional Korean marinades, soy sauce and hot-pepper paste, and raw marinated meat were then treated with 7.4, 12.2, or 15.2 MPa $CO_2$ at $31.1^{\circ}C$for 10 min. The SC-$CO_2$ treatments had no effect on the meat pH (p>0.05) or Warner-Bratzler shear force (p>0.05). There was no significant difference (p>0.05) in the total loss (sum of treatment loss and cooking loss) between the control and SC-$CO_2$ treated samples at 15.2 MPa (soy sauce marinated pork: 21.78 vs. 18.97%; hot-pepper marinated pork: 21.61 vs. 18.01%). After the SC-$CO_2$ treatment, lighter surface colors were observed in the treatment samples compared to those of the control samples (p< 0.001). However, tasting panelists were unable to distinguish a difference in color or in overall acceptability of the control and treatment (p>0.05). In the case of soy sauce marinated pork, when SC-$CO_2$ applied at 15.2 MPa and $31.1^{\circ}C$for 10 min, treatment samples showed a tenderer meat than the control samples. Therefore, the SC-$CO_2$ treatment conditions had no adverse effects on the sensory quality characteristics of the marinated meat products.

비만학생들의 운동후 회복시 초과 산소소비량 및 지속시간에 관한 연구

박철호,권민호,고봉민,박은경,우상헌 東亞大學校附設스포츠科學硏究所 1999 스포츠科學硏究論文集 Vol.17 No.-

The purpose of this study was to examine the effect of two different intensity of continuous exercise on magnitude of excess post-exercise oxygen consumption(EPOC), energy consumption following a 20min treadmill exercise. The subjects of this study were eight super-obesity in middle school students who were above 13 years old. subjects participated in two different exercise intensity to measure respiratory gas, blood lactate concentration and eardrum temperature. The results of this study were as follows: 1. The Energy consumption of the high intensity (80% VO₂ max) exercise group (264.68 35.60cal) was greater than that of the low intensity (50%) exercise group(172.01 20.39 Cal)(p<.001). 2. The EPOC of the high intensity exercise group (22.36+ 6.82Cal ) was greater than that of the low intensity exercise group(15.39+5.27 Cal)(p<.001). 3. The EPOC duration of th high intensity exercise group(28.36=3.56min) was longer than that of the low intensity exercise group(17.23+1.25min)(p<.001) 4. The blood lactate concentration, respiratory exchange ratio and temperature of the high intensity exercise group were greater than those of the low intensity exercise group(p<.05,p<.01). EPOC and duration were increase with 80%VO₂max, 80% VO₂max as intensity exercise got higher this also showed that it had something to do with lactate concentration in blood and increase of body temperature in the conclusion. We considered that there was a difference in using methods of energy, as there was a similar difference in RER. We though this following with oxygen consumption after exercise, we could clarify that high intensity exercise was better than lower intensity exercise in sametime for those who are obese especially adolescents to maintain their weights on the aspect of effect.

Effect of spark plasma sintering conditions on the thermoelectric properties of (Bi_0.25Sb_0.75)₂Te₃ alloys

Lim, Sang-Soon,Kim, Ju-Heon,Kwon, Beomjin,Kim, Seong Keun,Park, Hyung-Ho,Lee, Ki-Suk,Baik, Jeong Min,Choi, Won Jun,Kim, Dong-Ik,Hyun, Dow-Bin,Kim, Jin-Sang,Baek, Seung-Hyub Elsevier 2016 JOURNAL OF ALLOYS AND COMPOUNDS Vol.678 No.-

<P><B>Abstract</B></P> <P>As a field-assisted technique, spark plasma sintering (SPS) enables densification of specimens in a very short period of time compared to other sintering techniques. For high performance thermoelectric material synthesis, SPS is widely used to fabricate nanograin-structured thermoelectric materials by rapidly densifying the nanopowders suppressing grain growth. However, the microstructural evolution behavior of thermoelectric materials by SPS, another important process during sintering, has been rarely studied. Here, we explore SPS as a tool to control the microstructure by long-time SPS. Using p-type (Bi<SUB>0.25</SUB>Sb<SUB>0.75</SUB>)<SUB>2</SUB>Te<SUB>3</SUB> thermoelectric materials as a model system, we systematically vary SPS temperature and time to understand the correlations between SPS conditions, microstructural evolution, and the thermoelectric properties. Our results show that the relatively low eutectic temperature (∼420 °C) and the existence of volatile tellurium (Te) are critical factors to determine both microstructure and thermoelectric property. In the liquid-phase sintering regime, rapid evaporation of Te leads to a strong dependence of thermoelectric property on SPS time. On the other hand, in the solid-phase sintering regime, there is a weak dependence on SPS time. The optimum thermoelectric figure-of-merit (Z) of 2.93 × 10<SUP>−3</SUP>/K is achieved by SPS at 500 °C for 30 min. Our results will provide an insight on the optimization of SPS conditions for materials containing volatile elements with low eutectic temperature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spark plasma sintering (SPS) is used to synthesize the thermoelectric (Bi<SUB>0.25</SUB>Sb<SUB>0.75</SUB>)<SUB>2</SUB>Te<SUB>3</SUB>. </LI> <LI> Liquid phase and volatile element are a key for the microstructure and thermoelectric property. </LI> <LI> Thermoelectric figure-of-merit of 2.9 × 10<SUP>−3</SUP>/K is achieved at 500 °C for 30 min. </LI> </UL> </P>

제 2형 콜라겐에 의해 경구관용 유도된 DBA/1 mice에서의 세포면역반응

양형인 ( Hyung In Yang ),김완욱 ( Wan Uk Kim ),민도준 ( Do Jun Min ),박성환 ( Sung Hwan Park ),홍연식 ( Yeon Sik Hong ),이상헌 ( Sang Heon Lee ),조철수 ( Chul Soo Cho ),김호연 ( Ho Youn Kim ) 대한류마티스학회 2000 대한류마티스학회지 Vol.7 No.4

Objective: To investigate the dosage of bovine type II collagen (BnCII) for the induction of oral tolerance in CIA animals, and to verify the changes of immune response and TGF-β production of mesenteric lymph node cells in tolerized CIA animals. Methods: Oral tolerance was induced by feeding of variable doses (5㎍, 10㎍, 20㎍ and 40㎍) of BnCII to DBA/1 mice 4 times per week during 2 weeks, and control mice were given ovalbumin (1000㎍), before immunization. We examed clinical assessment; incidence of arthritis, severity of arthritis, arthritic limb by visual analysis. IgG antibodies to BnCII were measured by ELISA, T cell responses to BnCII and PHA were quantified by antigen (CII)-induced 3H-thymidine incorporation into lymphocytes of mesenteric lymph node, draining lymph node, and spleen. TGF-β in supernatants obtained from lymph node culture medium was measured by ELISA. Results: Arthritis limbs were observed in 100% of control at 5 weeks after subcutaneous BnCII injection. The incidences of CIA in all tolerized group were significantly lower than that in control 5 weeks after immunization (control 100% vs. 5㎍ feeding group: 50%, 10㎍ feeding group: 50%, 20㎍ feeding group: 50%, 40㎍ feeding group: 55.5%, P<0.01). In comparison to control, mean articular indices were lower in all tolerized groups (control 5.13: 5㎍ feeding group 3.50, 10㎍ feeding group 2.75, 20㎍ feeding group 2.87, 40㎍ feeding group 2.63, P<0.05). Arthritic limbs were also significantly lower in tolerized groups (control 58.3: 5㎍ feeding group 20.8, 10㎍ feeding group 16.7, 20㎍ feeding group 20.8, 40㎍ feeding group 20.8, P<0.05). The titers of IgG antibody to CII were lower in tolerized group than that in control [tolerized group; median 10 (min. 0, max. 48), control; median 33 (min. 8.6, max. 101), P<0.05]. The proliferative responses to BnCII were significantly suppressed in tolerized (control 8010±2319cpm, tolerized group 4500±2060cpm, P<0.01). High TGF-β production was noted in tolerized group (control; 28pg/ml, BnCII feeding group; 73pg/ml). Conclusion: Oral tolerance in DBA/1 mice was successfully induced from low doses of BnCII (5㎍) and suppressed T and B cell function in conjunction with increased TGF-β production may play an important role for the induction of CII induced oral tolerance in DBA/1 mice.

식용유지의 誘電특성에 관한 연구

민용규,정헌상 충북대학교 농업과학기술연구소 1991 農業科學硏究 Vol.9 No.2

In order to predict the quality of edible oils with electric properties the dielectric properties of the fresh and the thermally oxidized soybean and corn oil were determined at room temperature in the frequency from 0.2 to 100kHz, and also physical and chemical properties of these oils were determined by AOAC methods and the correlationship among these properties was investigated. Thermal oxidation was carried out at 180℃ for 12 hrs. The dielectric constant of edible oils showed the characteristic of Debye's dispersion with frequency and remarkable decrease around 1kHz. Dielectic loss tangent showed the peek around 4kHz frequency. These phenomena could be thought as the result from the frequency properties of dipole orientational polarization. Due to the increase of polar materials, free fatty acid value, peroxide value, density, dielectric constant, and dielectric loss tangent increased in proportion to the thermal oxidation time. Accordingly, the index of rancidity of edible oils could be predicted by measurement of the dielectnc properties. Key Words : Soybean oil, Corn oil, Dielectric constant, Thermal oxidation, Dielectric loss tangent.

3-Trolley Portainer Crane 운전 시뮬레이터의 개발

정민포,김규년,정태동,최제헌,김종훈 울산대학교 1994 공학연구논문집 Vol.25 No.2

항만에서, 빠른 시간내에 많은 양의 컨테이너 박스를 운반하는것이 곧 비용 절감이다. 이를 위해서는 크레인의 성능을 미리 예측을 할 수 있어야 한다. 특히 새로운 크레인을 제작할때, 실제 시험을 해본후 그 성능을 알아내기란 어려운 실정이다. 따라서, 컴퓨터상에서 이를 미리 시뮬레이션하여 그 성능을 알아낸다면 여러면에서 비용절감의 효과를 얻을수 있다. 본 연구에서는 기존의 하나의 Trolley에 의해 운전되는 크레인보다 더 나은 성능을 위해 설계된 3-Trolly Portainer Crane을 시뮬레이션하는 소프트웨어를 개발했다. 이것은 3개의 Torolley가 동시에 작동하여 하나일때보다 더 빠른 시간에 작업을 완수할수가 있다. 이 사실을 시뮬레이션을 통해 증명하고, 다양한 결과 자료를 이용해서 실제 이 크레인의 제작에도 상당히 도움이 될수 있다. 또한, 3개가 동시에 움직여서 각 구간별 소요시간의 측정이 문제가 되지만, 이것을 하나의 task로 미리 계산할 수 있는 방법을 고안, 적용하여 완수 하였다. In the port, it is a reduction of cost to load or unload many containers quickly. To do so, we should predict the performance of crane. Therefore, if we could simulate a crane operation and estimate the performance by the computer system, we can obtain a benefit of cost. In this study, we developed an operation simulator system of the 3-Trolley Portainer Crane which is designed for more efficeincy. Conceptually, the 3-Trolley Portainer Crane is operated concurrently by 3 trolleys, so it is faster than 1-Trolley Portainer Crane. We proved that through the simulation. It will be useful to manufactrue 3-Trolley Portainer Crane with many results from this software system. Also, the problem that must be calculated in parallel is solved by a single calculation method which we developed.