• 자원리싸이클링
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• 제14권1호
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• pp.55-63
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• 2005

This study investigated the electrochemical recovery of palladium in a HCl solution that is used for palladium leaching. The high acidity of HCl solution and the low concentration of Pd ions increased the cathodic overpotential and reduced the limiting current density. Lowering the current density produced dense deposits; however, they were under high tensile stress. Raising the temperature affected both the densification and the stress, which enabled the attainment of dense Pd deposits under low stress. Lowering the current density and raising the temperature up to 70$^{\circ}C$ was recommended for the recovery of palladium as sound bulk Pd deposits. Current efficiency was over 85% at the initial stage of recovery may decrease the current efficiency, since a low Pd ion concentration results in a low limiting current density.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2002년도 제9회 학술 발표회 프로그램과 논문초록
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• pp.41-41
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• 2002

Tolaasin, a pore-forming 1.9 kDa peptide toxin released by Pseudomonas tolaasii, produces brown blotch disease on cultivated oyster mushrooms. To investigate the mechanism of tolaasin-induced cell disruption, we studied the effect of temperature on the hemolytic process. In the kinetic analyses, single exponential function was fitted to the data obtained from temperature-dependent velocity of hemolysis(1/t$\_$50/, implying that there is a major time-limiting factor on the temperature-dependent hemolysis.(omitted)

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권4호
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• pp.210-218
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• 2000

For the fabrication of $YBa_2Cu_3O_x$ thick film, a substrate of $Y_2BaCuO_5$ was fabricated by adding $CeO_2$ into $Y_2BaCuO_5$ and two types of doping materials added with binder material were prepared. Each doping material was patterned on $Y_2BaCuO_5$substrate by the screen printing method and then was annealed at the temperature with a few step. It could be observed by X-ray diffraction patterns and SEM photographs that through the diffusion process of the $Y_2BaCuO_5$ and each doping material, the $YBa_2Cu_3O_x$ phase was formed. And with n additive of $CeO_2$ the thickness of formed $YBa_2Cu_3O_x$decreased. From the experiment of current limiting on thick film, the sample with thiner thickness of $YBa_2Cu_3O_x$ showed the more effective characteristics of current limiting.

• 한국전기전자재료학회논문지
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• 제16권12S호
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• pp.1286-1291
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• 2003

Quench behavior of resistive superconducting fault current limiters (SFCLS) with various pattern shapes was investigated. The pattern shapes employed were meander, bi-spiral, and spital shapes of identical line width, gap and margin. SFCLS were fabricated from YBCO thin films grown on two-inch diameter Al$_2$O$_3$ substrates under the same conditions. The total length of current limiting paths was the shortest at the spital shape due to its larger useless space. Inductance component of SFCLs with the spiral shape was around two times as high as those of other two shapes. This is not desirable since impedance characteristics of existing power systems can be changed. Resistance rise of current limiting elements was low at a spiral shape before the whole quench completion, which may act as a disadvantage for simultaneous quench in serial connection between current limiting elements, but the temperature tended to have similar values at higher voltages. On the other hand, hi-spital shape was severe at insulation level between current limiting lines. When these aspects were considered, we concluded that a meander shape was appropriate to design for a resistive SFCL based on thin films except the concentration of electric field at edge areas of strip lines.

• 한국환경과학회지
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• 제15권10호
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• pp.961-966
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• 2006

An algal assay procedure using an indigenous phytoplankton assemblage was tested to estimate the propagation of red tide phytoplankton species and determine the optimal time interval at which to measure growth yield in eutrophic marine waters where red tides frequently occur. Various red tide phytoplankton species were propagated on a large scale by adding nitrogen or phosphorous. This procedure was useful for estimating the limiting nutrient, elucidating the mechanisms underlying red tides, and determining the levels of increases in organic matter in eutrophic coastal waters. The algal assay using indigenous C. polykrikoides showed that this species did not always propagate, apparently because of very low concentrations of trigger elements that are necessary for its growth, rather than as a result of other environmental characteristics, e.g., water temperature or stress from sampling. In the winter, when water temperatures are lower than in spring, summer, or autumn, maximum propagation and the limiting nutrient could be estimated by measuring phytoplankton biomass at 2 - 3-day intervals. However, in the other seasons, when water temperatures are higher, phytoplankton biomass should be measured at 2-day intervals. In particular, daily monitoring will be required to determine precise growth yields in warm seasons.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.396-399
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• 2003

4H-SiC un diodes with field limiting rings(FLRs) were fabricated and characterized. The dependences of reverse breakdown voltage on the number of FLRs, the distance between p-base main junction and first FLR, and activation temperatures, were investigated. Al and B ions were implanted and activated at high temperature to form p-base region and p+ region in the n-epilayer. We have obtained up to 1782V of reverse breakdown voltage in the un diode with two FLRs on loom thick epilayer. The differential on-resistances of the fabricated diode are $5.3m{\Omega}cm^2$ at $100A/cm^2$ and $2.7m{\Omega}cm^2$ at $1kA/cm^2$, respectively. All pn diodes with FLRs have higher avalanche breakdown voltages than that of diode without an FLR. Regardless of the activation temperature, the un diode with a FLR located 5um apart from main junction has the highest mean breakdown voltage around 1600V among the diodes with one ring. On the other hand, the pn diode with two rings showed different behavior with activation temperature. It reveals that high voltage SiC pn diodes with low on-resistance can be fabricated by using the FLR edge termination.

• 한국진공학회지
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• 제18권4호
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• pp.296-301
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• 2009

ZnO에 대한 박막증착 연구를 위하여 유도결합 플라즈마 원자층박막증착(inductively coupled plasma assisted atomic layer deposition: ICP-ALD) 장치를 제작하고, 장치에 대한 기본 공정조건을 설정하기 위하여 플라즈마를 유도하지 않은 상태에서 p-type Si(100) 기판 위에 ZnO 박막을 증착하는 다양한 실험을 수행하였다. Zn 전구체(precursor)로는 Diethyl zinc [$Zn(C_2H_5)_2$, DEZn]를, 반응가스(reaction gas)로는 $H_2O$를, 캐리어(carrier) 및 퍼지가스(purge gas)로는 Ar을 사용하였다. 기판온도 $150^{\circ}C$에서 DEZn, $H_2O$, Ar의 공급시간을 변화시켜가면서 자기제한적 표면반응(self-limiting surface reaction)에 의한 박막성장조건을 성공적으로 유도하였다. 기판온도를 변화시켜가면서($90{\sim}210^{\circ}C$) 증착실험을 반복하여, 본 장치에 대한 ALD 공정온도(thermal ALD process window)를 확립하고 성장된 ZnO박막에 대한 증착특성, 결정성, 불순물 및 내부조성비등을 조사하였다. ALD 공정온도는 기판온도 $110{\sim}190^{\circ}C$로써 이 구간에서의 박막 평균증착률은 0.29 nm/cycle로 일정하게 나타났다. 기판온도가 높아질수록 결정성이 향상되어 ZnO(002) 피크가 우세하였다. 모든 ALD 공정온도에서 Zn와 O로만 구성된 고순도의 ZnO 박막을 실현하였는데, 온도가 높아질수록 Zn와 O의 비가 1에 근접하며 안정된 hexagonal wurtzite ZnO 구조의 박막이 성장되었다.

• Archives of Pharmacal Research
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• 제2권2호
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• pp.89-97
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• 1979

To find out the rheological characteristics of several pharamaceutical semisolid products, experiments were carriedout over the temperature range of 20 to 30 .deg.C . From continuous shear rheograms obtained with a Ferranti-Shirley cone and plate viscometer, loop area, shear rates, ryild values, limiting viscosities and activation energies were calculated. The systems were metastable and their viscosity decreased with time. As the temperature was raised, products studied showed a decrease in viscosity and yield value.

• 한국초전도ㆍ저온공학회논문지
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• 제22권1호
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• pp.7-11
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• 2020

As demand for electricity in urban areas increases, it is necessary to improve electric power stability by interconnecting neighboring substations and high temperature superconductor (HTS) power cables are considered as a promising option due to its large power capacity. However, the interconnection of substations reduces grid impedance and expected fault current is over 45 kA, which exceeds the capacity of a circuit breaker in Korean grid. To reduce the fault current below 45 kA, a HTS power cable having a fault current limiting (FCL) function is considered by as a feasible solution for the interconnection of substations. In this study, a FCL HTS power cable of 600 MVA/154 kV, transmission level class, is considered to reduce the fault current from 63 kA to less than 45 kA by generating an impedance over 1 Ωwhen the fault current is induced. For the thermal design of FCL HTS power cable, a parametric study is conducted to meet a required temperature limit and impedance by modifying the cable core from usual HTS power cables which are designed to bypass the fault current through cable former. The analysis results give a minimum cable length and an area of stainless steel former to suppress the temperature of cable below a design limit.

• Ocean and Polar Research
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• 제29권4호
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• pp.349-366
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• 2007

Seasonal variations of various physicochemical components (temperature, salinity, pH, DO, COD, DOC, nutrients-silicate, DIN, DIP) and potential limiting factor for phytoplankton primary production were studied in the surface water of semi-enclosed Masan Bay. Seasonal variations of nutrient concentrations, with lower values in summer and winter, and higher in fall, are probably controlled by freshwater loadings to the bay, benthic flux and magnitude of occurrence of phytoplankton communities. Their spatial distributional patterns are primarily dependent on physical mixing process between freshwater and coastal seawater, which result in a decreasing spatial gradient from inner to outer part of the bay. In the fall season of strong wave action, the major part of nutrient inputs (silicate, ammonium, dissolved inorganic phosphorus) comes from regeneration (benthic flux) at sediment-water interface. During the summer period, high Si:DIN and Si:DIP and low DIN:DIP relative to Redfield ratios suggest a N- and secondarily P-deficiency. During other seasons, however, silicate is the potential limiting factor for primary production, although the Si-deficiency is less pronounced in the outer region of the bay. Indeed, phytoplankton communities in Masan Bay are largely affected by the seasonal variability of limiting nutrients. On the other hand, the severe depletion of DIN (relatively higher silicate level) during summer with high freshwater discharge probably can be explained by N-uptake of temporary nanoflagellate blooms, which responds rapidly to pulsed nutrient loading events. In Masan Bay, this rapid nutrient consumption is considerably important as it can modify the phytoplankton community structures.