• 한국임상수의학회지
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• 제10권1호
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• pp.95-99
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• 1993

A total of 108 Holstein calves with an average body weight of l19kg was studied in 4 farms in middle region of South Korea in late Autumn from November 8 to 27, 1991. Individuals were selected for treatment when they exhibited acute signs of pneumonia and had a rectal temperature of$\geq$4$0^{\circ}C$. Each animal received intramuscularly either danofloxacin at 1.25mg/kg once daily or oxytetracycline at 10mg/kg once daily for three consecutive days. The individuals which had a rectal temperature of$\geq$39.5$^{\circ}C$ at 24 hours after the third treatment received two further treatments. Treatment for three or five days with danofloxacin was very efficacious and superior to oxytetracycline in the treatment of calve pneumonia. Eighty-six per cent of 58 danofloxacin treated calves and sixty-six per cent of 50 oxytetracycline teated calves responded successfully to treatment for three days and the difference between treatment groups was highly significant. Danofloxacin was more efficacious than oxytetracycline in rapid and complete control of pyrexia and in resolution of clinical signs. The minimum inhibitory concentration of danofloxacin for Pasteurella hemolytica and Pasteurella multocida was equally 0.12~0.50 mcg/$m\ell$ while that of oxytetracycline for Pasteurella hemolytica and Pasteurella multocida was 2.0~4.0 and 4.0~16mcg/$m\ell$, respectively. During the treatment period side effect was not found in all animals of both treatment groups except some animals receiving oxytetracycline showed pain at the site of injection.

• 자원리싸이클링
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• 제17권1호
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• pp.66-72
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• 2008

폐알칼리망간전지로부터 침출과 공침반응을 이용하여 Mn-Zn ferrite 분말을 제조하기 위한 기초실험을 수행하였다. 100g/L 광액 농도 3.0M $H_2SO_4$, $60^{\circ}C$ 및 교반속도 200 rpm의 조건에서 과산화수소 30ml를 첨가하여 얻어진 아연과 망간의 침출율은 각각 97.9%, 93.9% 이상이었으며, 침출용액을 가지고 반응시간, 반응온도, $O_2$ 가스량을 조절하며 공침반응을 진행하였다. 공침반응 결과 pH 12, $80^{\circ}C$, $O_2$ 1.3L/min, 교반속도 400 rpm의 조건에서 Mn-Zn ferrite를 저온 합성할 수 있었다. 합성된 Mn-Zn ferrite분말은 $0.143{\mu}m$의 구형 ferrite로서 80 emu/g의 포화자화값을 가지고 있었다.

• 방사선산업학회지
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• 제9권4호
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• pp.187-192
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• 2015

CD44 is a particular adhesion molecule and facilitates both cell-cell and cell-matrix interactions. In particular, splice variants of CD44 are particularly overexpressed in a large number of malignancies and carcinomas. In this study, the $^{177}Lu$-labelled CD44 targeting antibody was prepared and bioevaluated in vitro and in vivo. Anti-CD44 was immunoconjugated with the equivalent molar ratio of cysteine-based DTPA-NCS and radioimmunoconjugated with $^{177}Lu$ at room temperature within 15 minutes. The stability was tested in human serum. An in vitro study was carried out in HT-29 human colon cancer cell lines. For the biodistribution study $^{177}Lu$-labelled anti-CD44 was injected in xenograft mice. Anti-CD44 was immunoconjugated with cysteine-based DTPA-NCS and purified by a centricon filter system having a molecular cut-off of 50 kDa. Radioimmunoconjugation with $^{177}Lu$ was reacted for 15 min at room temperature. The radiolabeling yield was >99%, and it was stable in human serum without any fragmentation or degradation. The radioimmunoconjugate showed a high binding affinity on HT-29 colon cancer cell surfaces. In a biodistribution study, the tumor-to-blood ratio of the radioimmunoconjugate was 43 : 1 at 1 day post injection (p.i) in human colon cancer bearing mice. The anti-CD44 monoclonal antibody for the targeting of colon cancer was effectively radioimmunoconjugated with $^{177}Lu$. The in vitro high immunoactivity of this radioimmunoconjugate was determined by a cell binding assay. In addition, the antibody's tumor targeting ability was demonstrated with very high uptake in tumors. This radioimmunoconjugate is applicable to therapy in human colon cancer with highly expressed CD44.

• 대한금속재료학회지
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• 제48권7호
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• pp.630-638
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• 2010

The present investigation has been performed on the mixing behavior and microstructural development during fabrication of Fe micro-nano powder feedstock for a micro-powder injection molding process. The mixing experiment using a screw type blender system was conducted to measure the variations of torque and temperature during mixing of Fe powder-binder feedstock with progressive powder loading for various nano-powder compositions up to 25%. It was found that the torque and the temperature required in the mixing of feedstock increased proportionally with increasing cumulative powder loading. Such an increment was larger in the feedstock containing higher content of nano-powder at the same powder loading condition. However, the maximum value was obtained at the nano-powder composition of not 25% but 10%. It was owing to the 'roller bearing effect' of agglomerate type nano-powder acting as lubricant during mixing, consequently leading to the rearrangement of micro-nano powder in the feedstock. It is concluded that the improvement of packing density by rearrangement of nano-powders into interstices of micro-powders is responsible for the maximum powder loading of about 71 vol.% in the nano-powder composition of 25%.

• 한국추진공학회지
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• 제17권4호
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• pp.81-88
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• 2013

케로신과 액체산소를 추진제로 하는 다단연소방식 액체엔진용 산화제 과잉 예연소기를 설계하여 설계점에서 연소시험을 수행하였다. 설계된 산화제 과잉 예연소기는 산화제 일부와 연료를 혼합헤드를 통해 연소실에 공급하여 연소시키고 나머지 산화제를 연소실 재생냉각채널을 거쳐 연소실 중앙의 분사공을 통해 연소실로 주입하여 기화시키는 형태로 최종적으로 연소압 20 MPa, 혼합비 60에서 작동한다. 혼합헤드에는 단일 와류형 분사기를 벌집형태로 배열하였으며 가스 온도 균일성 향상과 연소 안정성 향상을 위한 혼합링과 터빈까지의 배관을 고려한 노즐을 장착하였다. 설계점 연소시험에서 산화제 과잉 예연소기는 높은 연소 안정성과 생성가스의 균일한 온도분포를 보였다.

• 설비공학논문집
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• 제20권6호
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• pp.381-387
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• 2008

The presence of non-condensable gases as an additional thermal resistance inside a refrigerating circuit has been found for a general refrigerator, The effect of non-condensable gases was varied by controlling the injection amount of dry air into the refrigerating circuit to increase a thermal resistance. Energy consumption tests for the refrigerator were conducted under the various amounts of non-condensable gases. The tested refrigerating circuit was the household refrigerator. As the molar fraction of non-condensable gases was increased from 0% to 1.46%, the amount of energy consumption was found to increase up to 25%. The increase of the amount of non-condensable gases in refrigerating circuit was found to result in increasing the condensation temperature at the condenser and decreasing the evaporation temperature at the evaporator, which were presumably caused by the low specific heat and increased partial pressure of non-condensable gas.

• 한국압력기기공학회 논문집
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• 제15권1호
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• pp.71-76
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• 2019

Actual stress distributions in the nozzle of a pressure vessel may not be in plane strain condition, implying that the crack-tip constraint condition may be relaxed in the nozzle. In this paper, a methodology for evaluating the fracture toughness of the ASME Code is presented considering the relaxation of the constraint effect in the nozzle of the reactor pressure vessel. The crack-tip constraint effect is quantified by the T-stress. The equation, which represent the relation between the fracture toughness in the lower constraint condition and the plane strain fracture toughness, is derived using the T-stress. This equation is similar to the method for evaluating the fracture toughness of the Master Curve for low constraint conditions. As a result of evaluating the fracture toughness considering the constraint effect in the reactor inlet, outlet and direct injection nozzles using the proposed equation, it was confirmed that the fracture toughness in the nozzles is higher than the plane strain fracture toughness. Applying the proposed evaluation methodology, it is possible to reflect the relaxation of the constraint effect in the nozzles of the reactor pressure vessel, therefore, the safe operation area on the pressure-temperature limit curve can be prevented from being excessively limited.

• Advances in Energy Research
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• 제6권1호
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• pp.75-90
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• 2019

Anthropogenic greenhouse gas emissions are rising rapidly despite efforts to curb release of such gases. One long term potential solution to offset these destructive emissions is the capture and storage of carbon dioxide. Partially depleted hydrocarbon reservoirs are attractive targets for permanent carbon dioxide disposal due to proven storage capacity and seal integrity, existing infrastructure. Optimum well completion design in depleted reservoirs requires understanding of prominent geomechanics issues with regard to rock-fluid interaction effects. Geomechanics plays a crucial role in the selection, design and operation of a storage facility and can improve the engineering performance, maintain safety and minimize environmental impact. In this paper, an integrated geomechanics workflow to evaluate reservoir caprock integrity is presented. This method integrates a reservoir simulation that typically computes variation in the reservoir pressure and temperature with geomechanical simulation which calculates variation in stresses. Coupling between these simulation modules is performed iteratively which in each simulation cycle, time dependent reservoir pressure and temperature obtained from three dimensional compositional reservoir models in ECLIPSE were transferred into finite element reservoir geomechanical models in ABAQUS and new porosity and permeability are obtained using volumetric strains for the next analysis step. Finally, efficiency of this approach is demonstrated through a case study of oil production and subsequent carbon storage in an oil reservoir. The methodology and overall workflow presented in this paper are expected to assist engineers with geomechanical assessments for reservoir optimum production and gas injection design for both natural gas and carbon dioxide storage in depleted reservoirs.

• 한국자원공학회지
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• 제55권6호
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• pp.660-669
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• 2018

석유회수증진법은 저류층 내의 잔존 석유의 회수율을 높이는 기술로 그 종류가 다양하다. 이 중 화학적 공법에 사용되는 폴리머, 계면활성제는 온도, 염도 등에 영향을 받으므로 적용할 수 있는 저류층이나 생산조건에 제약이 있다. 이 연구에서는 최근 연구 자료를 기반으로 화학적 공법의 문제해결과 효율 향상을 위한 기술 개발에 대해 분석하였다. 고온 및 고염 조건에서 분해가 쉽게 발생하는 기존의 폴리머를 개선하기 위해 새로운 폴리머 및 주입법 기술이 개발되었고 석유회수증진이 비전통저류층으로 활용 범위를 확대함에 따라 셰일과 탄산염암 저류층에 적용 가능한 계면활성제 개발이 이루어지고 있다. 하지만 이러한 화학물질은 비용이 높아 아직까지 현장에서는 널리 활용되어지지 않고 있으며 추가적인 연구를 통해 비용을 절감할 수 있다면 석유회수증진을 위해 효과적으로 적용될 것이다.

• 대한금속재료학회지
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• 제46권10호
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• pp.683-690
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• 2008

In order to develop transparent electrodes for high efficiency GaN-based light emitting diodes (LEDs), the electrical and optical properties of the electron beam evaporated ITO contacts have been investigated as a function of the deposition temperature and flow rate of oxygen during the deposition. As the deposition temperature increases from $140^{\circ}C$ to $220^{\circ}C$, the resistivity of the ITO films decreases slightly from $4.0{\times}10^{-4}{\Omega}cm$ to $3.3{\times}10^{-4}{\Omega}cm$, meanwhile the transmittance of the ITO films significantly increases from 67% to 88% at the wavelength of 470 nm. When the flow rate of oxygen during the deposition increases from 2 sccm to 4 sccm, the resistivity of the ITO films increases from $3.6{\times}10^{-4}{\Omega}cm$ to $7.4{\times}10^{-4}{\Omega}cm$, meanwhile the transmittance of the ITO films increases from 86% to 99% at 470 nm. Blue LEDs fabricated with the electron beam evaporated ITO electrode show that the ITO films deposited at $200^{\circ}C$ and 3 sccm of the oxygen flow rate give a low forward-bias voltage of 3.55 V at injection current of 20 mA with a highest output power.