• 한국세라믹학회지
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• 제45권12호
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• pp.796-801
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• 2008

$LaGaO_3$ thin film was prepared on Ni-Fe metal porous substrate by Pulsed Laser Deposition method. By the thermal reduction, the dense $NiO-{Fe_3}{O_4}$ substrate is changed to a porous Ni-Fe metal substrate. The volumetric shrinkage and porosity of the substrate are controlled by the reduction temperature. It was found that a thermal expansion property of the Ni-Fe porous metal substrate is almost the same with that of $LaGaO_3$ based oxide. $LaGaO_3$ based electrolyte films are prepared by the pulsed laser deposition (PLD) method. The film composition is sensitively affected by the deposition temperature. The obtained film is amorphous state after deposition. After post annealing at 1073K in air, the single phase of $LaGaO_3$ perovskite was obtained. Since the thermal expansion coefficient of the film is almost the same with that of LSGM film, the obtained metal support LSGM film cell shows the high tolerance against a thermal shock and after 6 min startup from room temperature, the cell shows the almost theoretical open circuit potential.

• Fisheries and Aquatic Sciences
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• 제26권5호
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• pp.344-354
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• 2023

Food and feeding habits of large cyprinid fishes (Labeobarbus intermedius, Labeobarbus nedgia, and Labeo forskalii) had been investigated in the upper Blue Nile River, Ethiopia. Four sampling sites were selected and specimens were sampled during the post-rainy (November 2016) and dry (March 2017) seasons by gillnets of 6 cm, 8 cm, 10 cm, 12 cm, and 14 cm mesh sizes. Totally 401 fishes were collected and about 30.4% (122) of the samples were documented with empty guts and 279 (69.6%) of them were with non-empty guts. The whole contents of all non-empty gut specimens were taken, labeled, and preserved using a 5% formaldehyde solution for further analysis. In the laboratory, gut contents were examined and identified using compound and stereo microscopes. The relative importance of different food items in the diet compositions was analyzed using a frequency of occurrence and volumetric analysis. During the post-rainy season, insects and phytoplankton were mostly ingested as food items. However, during the dry season, phytoplankton was the most important food item in the diet of all cyprinid fishes of the river. Based on current study results, L. intermedius and L. nedgia might be omnivores in their diet but Labeobarbus forskalii seemed to be detritivorous.

• 대한기계학회논문집B
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• 제41권10호
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• pp.639-647
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• 2017

Solid SCR에 사용 가능한 암모니아 저장물질의 하나인 암모니움 카바메이트는 열 분해시 이산화탄소 가스와 암모니아 가스를 생성하며, 분해 온도인 $60^{\circ}C$ 이하에서 암모니움 염으로 재결합되는 단점이 있다. 이러한 재결합 현상을 극복하기 위하여, 희석기체인 압축공기를 이용하여 기초가시화 실험을 수행하였다. 또한, 재결합 현상을 계량화하기 위하여, 재결합 물질의 무게변화를 측정하기 위한 간단한 장치를 만들어 자동차환경에서 사용되는 SUS재질의 3가지 관경에 크기에 대한 상관관계를 검토하였다. 아크릴 튜브로 제작된 온도조절이 가능한 가시화 실험장치에, 암모니아 가스, 이산화탄소 가스, 희석기 체인 질소 가스를 공급하며, 재결합 방지를 위한 온도, 압력, 희석유량과의 관계를 고찰하고, Chapman-Enskog Theory에서 파생된 Diffusivity를 사용하여 재결합 조건을 유추할 수 있는 지표로 사용하고자 한다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.425-428
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• 2000

본 연구에서는 재조합단백질 생산을 위한 식물세포배양용 세포배양기 운전에서 배지교환식 배양과 기체조성에 따른 영향을 관찰하였다. 배지교환식 배양에서는 6일째에 배지교환을 시작하는 것이 세포의 생장을 저해하지 않았으며 교환용 배지의 조성을 120 g/L sucrose와 2배 농축된 염농도를 하였을 때 가장 높은 세포농도인 20.0 gDCW/L를 나타내었으며 GUS 생산량은 60 g/L sucrose와 기본배지와 같은 농도의 염농도로 배지를 교환했을 때 12.9 U/mL로 다른 경우에 비하여 $1.5^{\sim}4.6$ 배 증가된 결과를 보였다. 그리고 $CO_2$의 농도를 5%로 높인 공기로 통기했을 때는 세포의 초기생장을 증진시켰으며 0.2 vvm의 통기량에서 5% $CO_2$로 통기시킨 경우는 일반 공기를 0.1 vvm으로 통기시킨 경우보다도 77% 높은 GUS의 생산량을 나타내었다.

• 설비공학논문집
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• 제4권2호
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• pp.123-136
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• 1992

A preliminary thermodynamic design model of two-evaporator refrigerator/freezer system is constructed. This system is based on Lorentz-Meutzner cycle using refrigerant mixtures. This model screens alternative refrigerant (R32, R125, R143a, R22, R134a, R152a, R124, R142b, R123) mixtures to select the best performance-giving refrigerant mixtures and its composition for the system. Also, it estimates the effects of cooling temperatures of intercoolers, evaporator's area ratio, cooling load ratio on the performance of the system. The COP of the system ranges from 1.4 to 1.6, which is superior to that of the single evaporator system charged with R12 by 13% to 29%. Among 15 mixtures, R22/R123, R143a/R123, R32/R142b, and R32/R124 (in the order of high COP) are most recommendable. For the case of R22/R123, R22 mass fraction more than 0.5(Load Ratio=1.0) or 0.7(Load Ratio=0.33) is recomended in order to replace R12 without reduction in volumetric capacity when keeping the compressor as the same one. COP has the highest value with X(R22)=0.7 and 0.8, respectively. For the case of R143a/R123, in the similar manner, mass fraction of R143a is more than 0.5 or 0.6 while best performance occurs at X(R143a)=0.8. Higher temperature intercooler is more important for the performance of the system than lower temperature intercooler. The area ratio of evaporators is roughly proportional to load ratio of the evaporators.

• 한국지역사회생활과학회지
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• 제14권3호
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• pp.89-98
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• 2003

To assess the actual status of businesses selling fermented soybean products, this study surveyed 130 Farmhouse style small size soybean sauce processing sites supported by the Rural Development Administration nationwide. The sex composition of the businesses representatives of 2% male and 98% female showed that a farmhouse soybean processing business is generally operated by rural women as a non-filming business. The percentage of co-worked sites was 71.2 and that of sites with permits was 39.2. The main products were meju, doenjang, and kanjang. Total production volume was found to be 523 tons, 256 tons, and 135 k$\ell$s, respectively. The number of years of experience of the manufacturers of the kanjang and doenjang was found to be 25.7 on average which shows that long-experienced, skilled manufacturers are participating in this project. The traditional measuring unit differed greatly depending on the region. This difference in the measuring unit of soybeans resulted in a large difference in the volume of doenjang and kanjang produced Per Province. For one kg of raw soybeans, the weight of Doenjang produced also varied from 2.14 kg in the Gyeongbuk area to 1.62 kg in Jeju. In the aspect of salt use, 1.75 $\ell$ (translated by volumetric unit 0.704 due) of salt pet kg of meju, in Jeju, was the highest in Korea. Government supervision would be beneficial in the areas of raw material products, standardization of measuring units and production methods, organization and operation of a conference for the different groups of producers, and in construction of a nationwide database.

• 한국도로학회논문집
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• 제15권4호
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• pp.107-116
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• 2013

PURPOSES: The liquid-type chemical warm-mix asphalt (WMA) additive has been developed. This study evaluates the basic properties of the additive and the mechanical properties of WMA asphalt and mixture manufactured by using the newly developed chemical additive. METHODS: First, the newly developed WMA additive was applied to the original asphalt by various composition of additive components and dosage ratio of additive. These WMA asphalt binders were evaluated in terms of penetration, softening point, rotational viscosity, and PG grade. Based on the binder test results, one best candidate was chosen to apply to the mixture and then the mechanical properties of WMA mixture were evaluated for moisture susceptibility, dynamic modulus, and rutting and fatigue resistance. RESULTS : According to the binder test, WMA asphalt binders showed the similar properties to the original asphalt binder except the penetraion index of WMA additive was a little higher than original binder. From the Superpave mix design, the optimum asphalt content and volumetric properties of WMA mixture were almost the same with those of hot mix asphalt (HMA) mixture even though the production and compaction temperatures were $30^{\circ}C$ lower for the WMA mixture. From the first set of performance evaluation, it was found that the WMA mixture would have some problem in moisture susceptibility. The additive was modified to improve the resistance to moisture and the second set of performance evaluation showed that the WMA mixture with modified chemical additive would have the similar performance to HMA mixture. CONCLUSIONS : Based on the various laboratory tests, it was concluded that the newly developed chemical WMA additve could be successfully used to produce the WMA mixture with the comparable performance to the HMA mixture. These laboratory evaluations should be confirmed by applying this additive to the field and monitoring the long-term performance of the pavement, which are scheduled in the near future.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.277-277
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• 2010

The capacity of the carbonaceous materials reached ca. $350\;mAhg^{-1}$ which is close to theorestical value of the carbon intercalation composition $LiC_6$, resulting in a relatively low volumetric Li capacity. Notwithstanding the capacities of carbon, it will not adjust well to the need so future devices. Silicon shows the highest gravimetric capacities (up to $4000\;mAhg^{-1}$ for $Li_{21}Si_5$). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. We focused on electrode materials in the multiphase form which were composed of two metal compounds to reduce the volume change in material design. A combination of electrochemically amorphous active material in an inert matrix (Si-M) has been investigated for use as negative electrode materials in lithium ion batteries. The matrix composited of Si-M alloys system that; active material (Si)-inactive material (M) with Li; M is a transition metal that does not alloy with Li with Li such as Ti, V or Mo. We fabricated and tested a broad range of Si-M compositions. The electrodes were sputter-deposited on rough Cu foil. Electrochemical, structural, and compositional characterization was performed using various techniques. The structure of Si-M alloys was investigated using X-ray Diffractometer (XRD) and transmission electron microscopy (TEM). Surface morphologies of the electrodes are observed using a field emission scanning electron microscopy (FESEM). The electrochemical properties of the electrodes are studied using the cycling test and electrochemical impedance spectroscopy (EIS). It is found that the capacity is strongly dependent on Si content and cycle retention is also changed according to M contents. It may be beneficial to find materials with high capacity, low irreversible capacity and that do not pulverize, and that combine Si-M to improve capacity retention.

• 한국지하수토양환경학회지:지하수토양환경
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• 제12권2호
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• pp.37-46
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• 2007

본 연구에서는 플라스틱과 Woodchip을 주원료로 하여 복합플라스틱계 담체를 개발하고 성능평가를 실시하였다. 개발담체는 기존상용화 담체에 비하여 처리효율 및 미생물 부착성 등은 유사하였으나, 경제적인 측면에서 우수한 것으로 평가되었다. 담체의 성능평가는 Lab scale의 바이오트리클링필터에 개발담체를 충진하여 톨루엔과 황화수소를 대상으로 제거효율 및 운전인자 등을 평가하였다. 본 연구에서 톨루엔 제거효율은 가스유입량 $1.5\;m^3/hr$, 유입농도 260ppm, 공탑체류시간 42s 운전조건에서 90% 이상으로 높게 나타내었으며, 톨루엔 최대제거능은 $77\;g/m^3{\cdot}hr$이었다. 황화수소와 톨루엔 동시제거 실험에서는 $H_2S$와 톨루엔이 효과적으로 제거되었다. $H_2S$의 최대제거능은 $100\;g-S/m^3{\cdot}hr$이었으며, $H_2S$ 농도가 100 ppm까지는 톨루엔제거에 영향을 주지 않았으나 $H_2S$ 농도가 증가함에 따라 톨루엔 제거효율은 감소되었다.

• 공업화학
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• 제21권5호
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• pp.488-494
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• 2010

W/O 에멀젼법하에 homogenizer를 사용하여 ${\alpha}$-알루미나 분체 제조 시 O : W 부피비, 교반속도, 계면활성제 사용량과 조성 및 종류 등의 변화에 의하여 분체의 입자형상, 응집성, 평균입경과 입도분포 등의 변화를 분석하였다. 계면활성제는 비이온 계면활성제가 사용되었고 단일 및 혼합계면활성제로는 SP80 및 [SP80 & TW80]을 사용하였고 보조계면활성제로는 n-부탄올을 사용하였다. SP80을 사용하였을 경우, 분체의 입자형상은 구형에 근접하였고 평균입경은 주어진 O : W 부피비 변화 및 16000 rpm 이상의 교반속도에서 큰 차이를 보이지 않았다. [SP80 & TW80]을 사용하였을 경우, 구형에 가까운 분체의 입자간 응집 및 합체현상은 $HLB_m$ = 5일 때 낮았고 평균입경은 단일계면활성제를 사용하였을 때 비하여 다소 감소하였다. $HLB_m$ = 5인 [SP80 & TW80]와 함께 0.1 vol% n-부탄올을 사용하였을 경우, 입자간 응집성이 상대적으로 낮고 나노크기의 입도를 갖는 분체 분율을 증가시킬 수 있었다.