• 한국산업융합학회 논문집
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• 제25권3호
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• pp.443-449
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• 2022

In this study, in order to improve the disadvantages of the environmental error of the infusion set that performs infusion therapy in the existing clinical practice and to maximize the user's convenience by miniaturizing the existing infusion pump system, the structure of the muscle pump of the human vein was imitated. As a double check valve method, a method for preventing the backflow of fluid and discharging a constant fluid in one direction by external pressure was proposed. The proposed bio-mimic muscle pump uses a check valve that controls the flow of fluid in one direction and a silicone tube with elasticity, and a chamber is constructed. A peristaltic pump for applying intermittent pressure to the tube chamber was constructed using a multi-cam structure roller. In order to verify the performance of the proposed pump, optimization was performed while changing the number of multi-cam rollers and adjusting the speed of the roller driving motor, and the reproducibility of the instantaneous discharge amount and the continuous discharge amount of the pump was compared and tested. The performance of the muscle pump proposed in this study was verified through experiments that it can inject up to 1L of fluid within 12 hours, and that it is possible to inject the fluid with an accuracy of ±0.1ml. Real-time monitoring of the fluid injection volume through the bio-mimic muscle pump proposed in this study not only increases the convenience of the administrator, but also provides a precise fluid administration environment to more patients at a low cost, and additionally applies bubble detection and occlusion detection technology If so, it is believed that a safer medical environment can be provided to patients.

• 한국안전학회지
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• 제37권5호
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• pp.80-88
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• 2022

The Korean nuclear industry had developed the SPACE (Safety and Performance Analysis Code for nuclear power plants) code, which adopts a two-fluid, three-field model that is comprised of gas, continuous liquid and droplet fields and has the capability to simulate three-dimensional models. According to the revised law by the Nuclear Safety and Security Commission (NSSC) in Korea, the multiple failure accidents that must be considered for the accident management plan of a nuclear power plant was determined based on the lessons learned from the Fukushima accident. Generally, to improve the reliability of the calculation results of a safety analysis code, verification is required for the separate and integral effect experiments. Therefore, the goal of this work is to verify the calculation capability of the SPACE code for multiple failure accidents. For this purpose, an experiment was conducted to simulate a Control Element Drive Mechanism (CEDM) break with a safety injection failure using the ATLAS test facility, which is operated by Korea Atomic Energy Research Institute (KAERI). This experiment focused on the comparison between the experiment results and code calculation results to verify the performance of the SPACE code. The results of the overall system transient response using the SPACE code showed similar trends with the experimental results for parameters such as the system pressure, mass flow rate, and collapsed water level in component. In conclusion, it can be concluded that the SPACE code has sufficient capability to simulate a CEDM break with a safety injection failure accident.

• 청정기술
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• 제15권2호
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• pp.130-136
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• 2009

상용촉매인 Johnson Matthey사 KATALCO 83-3 촉매를 이용하여 마이크로 채널 반응기 (micro-channel reactor: MCR) 형태에 따른 메탄올 수증기 개질반응을 통한 수소제조반응 특성 연구를 수행하였다. 반응온도 200${\sim}$300$^{\circ}C$, 공간속도 3,000${\sim}$10,000 $hr^{-1}$, 촉매 크기 0.05${\sim}$2.2 mm 조건을 갖는 고정층 반응기에서 반응활성 실험을 수행한 결과, 촉매 크기 0.35 mm에서 최적의 반응활성을 나타났다. 이 결과를 토대로 stacked bed, boat bed 등 마이크로 채널 반응기 형태에 따른 반응활성을 연구한 결과, stacked bed type 마이크로 채널 반응기가 더 좋은 반응활성을 가짐을 알 수 있었다.

• 한국초전도ㆍ저온공학회논문지
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• 제25권4호
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• pp.60-64
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• 2023

The manufacturing process of antibody drugs comprises two main stages: the upstream process for antibody cultivation and the downstream process for antibody extraction. The domestic bio industry has excellent technology for the upstream process. However, it relies on the technology of foreign countries to execute downstream process such as affinity chromatography. Furthermore, there are no domestic companies capable of producing the equipment for affinity chromatography. High gradient magnetic separation technology using a high temperature superconducting magnet as a novel antibody separation and purification technology is introduced to substitute for the traditional technology of affinity chromatography. A specially designed magnetic filter was equipped in the bore of the superconducting magnet enabling the continuous magnetic separation of nano-sized paramagnetic beads that can be used as affinity magnetic nano beads for antibodies. To optimize the magnetic filter that captures superparamagnetic nanoparticles effectively, various shapes and materials were examined for the magnetic filter. The result of magnetic separation experiments show that the maximum separation and recovery ratio of superparamagnetic nanoparticles are 99.2 %, and 99.07 %, respectively under magnetic field (3 T) and flow rate (600 litter/hr).

• 대한약리학회지
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• 제18권1호
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• pp.43-54
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• 1982

Bile formation is a complex process comprised of three separate physiologic mechanism operating at two anatomical sites. At present time, it was known that at least two processes are responsible for total canalicular secretion at the bile canaliculus. One of the processes is bile salt-dependent secretion (BSDS) hypothesis that the active transport of bile salts from plasma to bile provided a primary stimulus for bile formation: the osmotic effect of actively transported bile acid was responsible for the movement of water and ions into bile. The other process is bile salt-independent secretion (ESIS), which is unrelated to bile salt secretion at the canaliculus and which may involve the active transport of sodium. The third process for bile formation involves the biliary ductal epithelium. Secretin-stimulated bile characteristically contained bicarbonate in high concentration. Therefor, it was suggested that secretin stimulated water and bicarbonate secretion from the biliary ductules. One the other hand, it was found that a large amounts of cAMP was present in canine bile but no apparent relationship between bile salt secretion and cAMP content in dog bile. However, bile flow studies in human have demonstrated that secretin and glucagon increase bile cAMP secretion as does secretin in baboons. Secretin increases baboon bile duct mucosal cAMP levels in addition to bile CAMP levels suggesting that in that species secretin-stimulated bile flow may be cAMP mediated. It has been postulated that glucagon and theophylline which increase the bile salt-independent secretion in dogs might act through an increased in liver cAMP content. In a few studies, the possible role of cAMP on bile formation has teen tested by administration of an exogenous derivative of cAMP, dibutyryl cAMP. In the rat, DB cAMP did not modify bile flow, but injection of DB cAMP in the dog promoted an increase in the bile salt-independent secretion. Because of these contradictory results, this study was carried out to examine the relationship between cyclic nucleotides and bile flow due to various bile salts as well as secretin or theophylline. Experiments were performed in rabbits with anesthesia produced by the injection of seconal(30 mg/kg). Rabbits had the cystic duct ligated and the proximal end of the divided common duct cannulated with an appropriately sized polyethylene catheter. A similar catheter was placed into the inferior vena cava for administration of drugs. Bile was collected for determination of cyclic nucleotides and total cholate in 15 min. intervals for a few hours. The results are summerized as followings. 1) Administrations of taurocholic acid or chenodeoxycholic acid increased significantly the concentrations of cAMP and cGMP in bile of rabbits. 2) Concentration of cAMP in bile during the continuous infusion of ursodeoxycholic acid, was remarkedly increased in accordance with the increase of bile flow, while on the contrary concentration of cGMP in bile was decreased significantly. 3) Dehydrocholic acid and deoxycholic acid significantly increased bile flow, total cholate output and cyclic nucleotides in bile. 4) Only cAMP concentration in bile was significantly increased from control value by secretin, while theophylline increased cAMP as well as cGMP in rabbit bile. 5) In addition, the administration of secretin to taurocholic acid-stimulated bile flow increased cAMP while theophylline produced the increases of cAMP and cGMP in bile. 6) The administration of insulin to taurocholic acid-stimulated bile flow decreased cAMP concentration, while on the contrary cGMP was remarkedly increased in rabbit bile.

• 한국지하수토양환경학회지:지하수토양환경
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• 제11권2호
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• pp.68-76
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• 2006

실험실 규모의 반연속 흐름 2단 토양컬럼을 이용하여 사염화에틸렌(PCE)에서 에틸렌으로의 혐기성 환원 탈염소화 반응특성을 조사하였다. 국내의 TCE로 오염된 현장에서 토양을 채취하여 컬럼 반응조에 충진하고, lactate(전자공여체 그리고/혹은 탄소원으로서)와 PCE를 함유한 현장 지하수를 컬럼 반응조로 주입하였다. 운전초기 약 50일 경과기간 동안 유입 lactate와 PCE의 질량비는 620:1이었는데, 이때 PCE에서 cis-DCE로의 불완전한 환원성 탈염소화가 관찰되었다. 그러나 유입 lactate와 PCE의 질량비를 5,050:1로 증가시킨 두번째 운전기간동안 PCE에서 ethylene로의 완벽한 탈염소화를 관찰할 수 있었는데, 이는 초기 운전기간 동안의 적절한 전자공여체의 공급의 중요성을 보여 주었다. PCE에서 cis-DCE로의 탈염소화율은 $0.62{\sim}1.94\;{\mu}mol$ PCE/L pore volume/d이었고, cis-DCE에서 ethylene으로의 탈염소화율은 $2.76\;{\mu}mol$ cis-DCE/L pore volume/d으로 나타났다. 전체 시스템에서의 PCE에서 ethylene으로의 전환율은 $1.43\;{\mu}mol$ PCE/L pore volume/d이었다. 본 실험에서 PCE에서 cis-DCE로의 분해단계에서 수소의 농도는 $10{\sim}64\;mM$, 그리고 cis-DCE에서 에틸렌으로의 분해단계에서 수소의 농도는 $22{\sim}29\;mM$이었다. 본 연구에서의 이러한 긍정적인 실험 결과는 본 연구에서 조사된 TCE로 오염된 지하수의 현장 생물학적 복원을 위해 혐기성 환원 탈염소화 공정의 적용 가능성을 보여준다.

• Asian-Australasian Journal of Animal Sciences
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• 제23권4호
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• pp.491-500
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• 2010

Three experiments were conducted to investigate the effects of polyurethane coated urea on in vitro ruminal fermentation, ammonia release dynamics and lactating performance of Holstein dairy cows fed a steam-flaked corn-based diet. In Exp. 1, a dual-flow continuous culture was run to investigate the effect of polyurethane coated urea on nutrient digestibility, rumen fermentation parameters and microbial efficiency. Three treatment diets with isonitrogenous contents (13.0% CP) were prepared: i) feedgrade urea (FGU) diet; ii) polyurethane coated urea (PCU) diet; and iii) isolated soy protein (ISP) diet. Each of the diets consisted of 40% steam-flaked corn meal, 58.5% forages and 1.5% different sources of nitrogen. PCU and FGU diets had significantly lower digestibility of NDF and ADF (p<0.01) than the ISP diet. Nitrogen source had no significant effect (p = 0.62) on CP digestibility. The microbial efficiency (expressed as grams of microbial N/kg organic matter truly digested (OMTD)) in vitro of the PCU diet (13.0 g N/kg OMTD) was significantly higher than the FGU diet (11.3 g N/kg OMTD), but comparable with the ISP diet (14.7 g N/kg OMTD). Exp. 2, an in vitro ruminal fermentation experiment, was conducted to determine the ammonia release dynamics during an 8 h ruminal fermentation. Three treatment diets were based on steam-flaked corn diets commonly fed to lactating cows in China, in which FGU, PCU or soybean meal (SBM) was added to provide 10% of total dietary N. In vitro $NH_3-N$ concentrations were lower (p<0.05) for the PCU diet than the FGU diet, but similar to that for the SBM diet at all time points. In Exp. 3, a lactation trial was performed using 24 lactating Holstein cows to compare the lactating performance and blood urea nitrogen (BUN) concentrations when cows were fed PCU, FGU and SBM diets. Cows consuming the PCU diet had approximately 12.8% more (p = 0.02) dietary dry matter intake than those consuming the FGU diet. Cows fed the PCU diet had higher milk protein content (3.16% vs. 2.94%) and lower milk urea nitrogen (MUN) concentration (13.0 mg/dl vs. 14.4 mg/dl) than those fed the FGU diet. Blood urea nitrogen (BUN) concentration was significantly lower for cows fed the PCU (16.7 mg/dl) and SBM (16.4 mg/dl) diets than the FGU (18.7 mg/dl) diet. Cows fed the PCU diet had less surplus ruminal N than those fed the FGU diet and produced a comparable lactation performance to the SBM diet, suggesting that polyurethane coated urea can partially substitute soybean meal in the dairy cow diet without impairing lactation performance.

• 지질공학
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• 제20권3호
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• pp.281-295
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• 2010

새롭게 구축된 자동 흙-함수특성곡선 시험장치는 측정원리가 간단하고 연속적인 측정이 가능하며, 시험자에 의해 발생될 수 있는 오차를 최소화하여 보다 정확한 불포화토의 흙-함수특성곡선을 산정할 수 있다. 본 시험장치는 압력조절장치, 플로우셀, 물저장소, 공기방울트랩, 저울, 시료준비장치, 측정시스템 등으로 구성되어 있다. 공기의 압력은 0-300 kPa범위까지 적용할 수 있으며, 단기간내 시험을 완료할 수 있다. 본 시험장치에서는 건조과정과 습윤과정을 재현할 수 있으며, 측정 자동화 프로그램(SWRC)을 이용하여 건조과정과 습윤과정에 따른 시료내 함수비 변화를 실시간으로 확인할 수 있다. 본 시험기를 이용하여 상대밀도 75%인 주문진 표준사에 대한 건조 및 습윤과정의 체적함수비에 따른 모관흡수력을 측정하였다. 측정결과, 건조 및 습윤과정을 거치는 동안 동일한 체적함수비에서 대한 모관흡수력 값이 다르게 나타나는 이력현상(hysteresis)이 발생하였다. 측정된 결과를 토대로 기존의 Brooks and Corey, van Genuchten 및 Fredlund and Xing 방법을 이용하여 흙-함수특성곡선을 예측하였다. 결정계수를 이용하여 이들 방법에 대한 정확성을 평가한 결과 대상토질조건의 경우 van Genuchten방법이 신뢰성이 가장 높은 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.412-420
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• 2005

In order to investigate factors affecting the denitrification in the F-STEP PROCESS using a loess ball as support media and Pseudomonas DWC 17-8, calcining temperature, loess ball size, pH, nitrate concentration, working temperature, and inhibitor were studied in batch mode using synthetic sludge. A 5- 10 mm of loess ball (960$^{circ}$ of calcining temperature) was the most suitable for denitrification. When the initial pH was increased from 3.0 to 7.0, the removal efficiency of nitrate was increased. Specifically, at initial pH of 7.0, the maximum removal efficiency of nitrate was 5.0 mg/min. When the initial concentration of nitrate was increased from 100 to 400 mg/l, the removal efficiency of nitrate was proportional to the concentration of nitrate. The maximum removal efficiency of nitrate was 5.72 mg/min at 400 mg/l of initial concentration. When the operating temperature was increased from 10 to 30$^{circ}$, the removal efficiency of nitrate was increased from 0.76 to 6.15 mg/min, and at above 40$^{circ}$ of operating temperature, it was decreased from 4.0 to 2.0 mg/min. Among the various inhibitors, higher than 10$^{-1}$ M of sodium azide abolished this reaction completely. When the KCN concentration was above 10$^{-1}$ M, the reaction was inhibited completely. In the case of 2,4-dinitrophenol and sodium sulphide, it was inhibited at above 10$^{-2}$ M completely. For testing the various flow orders of the F-STEP PROCESS for effective denitrification using practical wastewater, continuous experiments under the optimum conditions were carried out for 60 days. Among the various processes, the PROCESS A gave the highest efficiencies of denitrification, nitrification, and total nitrogen (TN) removal with 86.5, 89.5, and $90\%$, respectively. For scale-up in the PROCESS A, real farm wastewater was used and pilot tests carried out for 90 days. The denitrification efficiency was $97.5\%$, which was increased by $12.7\%$. The efficiencies of TN removal and nitrification were 96.6 and $70.0\%$, respectively. The removal efficiency of chemical oxygen demand (COD) was $63.7\%$, which was increased by $20\%$.

• Korean Chemical Engineering Research
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• 제50권1호
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• pp.149-154
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• 2012

바이오필터담체가 충전된 흡착칼럼 운전 시의 흡착 및 탈착거동에 대하여 조사하였다. 에탄올을 휘발성유기화합물(VOC)로서 함유하는 폐가스를 처리하기 위한 연속동적흡착 실험을 바이오필터공정과 같은 90% 이상의 상대습도에서 수행하였다. 에탄올 1,000 ppmv(or 2,050 mg ethanol/$m^3$)를 포함하는 폐가스 2 L/min을 흡착칼럼에 공급하였을 때에 흡착칼럼 출구에서의 파과점과 흡착평형에 이르는 시간은 1단 시료구에서 보다 각각 10배와 3배 만큼 지연되었다. 한편 에탄올 2,000 ppmv(or 4,100 mg ethanol/$m^3$)를 포함하는 폐가스의 경우에는 각각 9배와 3배 지연되었다. 이와 같이 흡착칼럼 출구에서 지연기간의 비는 공급농도와 무관하게 서로 거의 일치하였음이 관찰되었다. 또한 1단 시료구와 출구에서 비교한 유입폐가스의 에탄올농도의 10%를 보이는 탈착시간 지연비도 약 1.5배로서 거의 일치하였다. 한편 미생물활성과 멸균공정의 흡착평형에 대한 영향에 대하여 조사하였다. 멸균된 입상 활성탄으로 충전된 vial의 기상 에탄올 농도는 멸균되지 않은 입상 활성탄으로 충전된 경우와 거의 일치하였다. 그러나 퇴비(compost)나 입상 활성탄/퇴비 혼합물의 경우에는 멸균 안한 경우가 멸균한 경우보다 기상에서의 에탄올 농도가 현저하게 높았다.