• Clinical and Experimental Reproductive Medicine
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• 제21권3호
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• pp.261-266
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• 1994

Semen preparation for Assisted Reproductive Technology(ART) involves the separation of the motile sperm from non-motile, dead sperm, cellular debris and seminal fluid. The aim of this study is to compare the motile sperm recovery rate and motility index of different sperm preparation method(swim-up method, 80% isotonic continuous percoll method, two-layer discontinuous percoll method, mini-percoll method). In Mini-Percoll method, pellets from patients were suspended in 0.3ml of medium and layerd on a discontinuous percoll gradient consisting of 0.3ml each of 50, 70, 95% isotonic percoll. All semen samples are divided into normal and subnormal sperm group(oligo-, astheno-, oligoasthenozoospermia). Especially, we evaluated the effect of mini-percoll method in subnormal sperm group. In normal sperm group, mini-percoll method and two layer discontinuous percoll method (40%/80%) allowed increasing of motile sperm recovery rate. But motility index was higher in swimup method than the other methods. In subnormal sperm group, mini-percoll method has advantages as compare with the other methods in motile sperm recovery rate and motility index. These results suggest that modified mini-percoll method could be certainly a valuable tool in some cases of severe male factor sperm.

• Membrane and Water Treatment
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• 제6권1호
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• pp.1-13
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• 2015

The modification of ultrafiltration membranes with carbon nanotube (CNT) buckypaper on fouling control was investigated. Two types of commercially available flat-sheet membranes were used: PS35 and PES900C/D (PES) (the PS35 membranes were hydrophilic with a molecular weight cutoff of 20 kDa, and the PES membranes were hydrophobic with a molecular weight cutoff of 20 kDa). The CNT buckypaper modified ultrafiltration membranes were prepared by filtering a CNT suspension through the flat-sheet membrane in a dead-end ultrafiltration unit. After modification, the pure water flux of PES was significantly increased, while the pure water flux of PS35 was decreased. The properties of the CNT modified membranes were also investigated. Considering the antifouling properties, pure water flux of the modified membrane, and the stability of CNT buckypaper layer on the membrane surface, ethanol solution with a concentration of 50 wt.%, multi-walled carbon nanotubes (MWCNTs) with a larger diameter (30-50 nm), and the CNT loading with $7.5g/m^2$ was selected. The CNT buckypaper on the surface of ultrafiltration membranes can trap the pollutants in sewage effluent and prevent them reaching the surface of virgin membranes. Water quality analysis showed that the effluent quality of the modified membrane was obviously improved. The removal efficiency of humic acid and protein-like matters by the modified membrane was significant. These results indicate the potential application of the CNT buckypaper layer modified membranes in the field of wastewater reclaim.

• Journal of Electrochemical Science and Technology
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• 제13권1호
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• pp.78-89
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• 2022

ANODE-free Li-metal batteries (AFLMBs) operating with Li of cathode material have attracted enormous attention due to their exceptional energy density originating from anode-free structure in the confined cell volume. However, uncontrolled dendritic growth of lithium on a copper current collector can limit its practical application as it causes fatal issues for stable cycling such as dead Li formation, unstable solid electrolyte interphase, electrolyte exhaustion, and internal short-circuit. To overcome this limitation, here, we report a novel dual-salt electrolyte comprising of 0.2 M LiPF₆ + 3.8 M lithium bis(fluorosulfonyl)imide in a carbonate/ester co-solvent with 5 wt% fluoroethylene carbonate, 2 wt% vinylene carbonate, and 0.2 wt% LiNO₃ additives. Because the dual-salt electrolyte facilitates uniform/dense Li deposition on the current collector and can form robust/ionic conductive LiF-based SEI layer on the deposited Li, a Li/Li symmetrical cell exhibits improved cycling performance and low polarization for over 200 h operation. Furthermore, the anode-free LiFePO₄/Cu cells in the carbonate electrolyte shows significantly enhanced cycling stability compared to the counterparts consisting of different salt ratios. This study shows an importance of electrolyte design guiding uniform Li deposition and forming stable SEI layer for AFLMBs.

• 한국가구학회지
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• 제29권1호
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• pp.31-39
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• 2018

Recently, as the continuously increasing of the one-person households, builders were focusing on a built-in furniture development for efficiency. Through the dead space of the space can be reduced. Also, Condensation that occurs in a built-in furnitures installation space may result in different results depending on the room's direction, floor, finish, adjacent room effect, occupant's lifestyle. In this background, it can be considered in terms of functional aspect and morphological aspect by using WUFI2D simulation system. As a result, the tendency of occurrence of condensation was examined by comparing the water content and the growth potential of fungus graph which came from WUFI2D. Results of this study are as followings: Built-in furniture, both top & bottom open, is more stable to condensation than the built-in furniture with the top or bottom open. Also, Among from the top floor built-in furniture to the bottom of it, the bottom one is more stable to condensation.

• Mycobiology
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• 제33권1호
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• pp.1-6
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• 2005

Morphological characteristics of hyphal interaction between Grifola umbellata (Pers. Ex Fr.) Pilat and its companion fungus which related to sclerotia formation from hyphae were investigated by external observations, light microscopy and transmission electron microscopy (TEM). External observations showed that a dense antagonism line was formed by both G. umbellata and companion fungus after their hyphae contacted each other in dual culture. Many hyphal strands emerged on the colony of G. umbellata and differentiated to sclerotia from where hyphal strands crossed. Light microscope observations revealed the process of antagonism line formation. Mature antagonism with structural differentiation, was composed of three main layers: the rind, the rind underlayer and the hypha layer. TEM observations showed that after colonies hyphal contact, a series of reactions always occurred in both G. umbellata and companion fungus. Cells in the center of antagonism line were dead. Cells of G. umbellata adjacent to the antagonism line were usually large and hollow, with unilateral thickened wall, whereas those of companion fungus were empty, with thin or thick wall. Both hyphal interaction at the antagonism line may be one of the main reasons for sclerotia of G. umbellata differentiation from hypha.

• 한국임상수의학회지
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• 제34권5호
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• pp.384-387
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• 2017

A dead male Jeju weasel with clinical signs of severe dehydration and moribund was submitted for the necropsy. Grossly, purple-red ecchymoses were scattered in the surface of the entire lungs. Milky-white mucoid materials occupied in the left bronchial lumens. Histopathologically, an adult worm with thick cuticle layer surrounded by chronic inflammatory cells was embedded in the left caudal lung lobe. Numerous oval or barrel-shaped parasitic eggs with muco-purulent exudates were observed in the dilated bronchus of another section of left caudal lobe. Operculate parasitic eggs showed typical morphologic characteristics such as barrel shape with asymmetry bipolar plugs and thick bi-layered wall. Based on the histopathologic findings and morphological characteristics of parasitic eggs in the pulmonary tissue section, this case was diagnosed as verminous pneumonia associated Eucoleus aerophilus infection in Jeju weasel.

• 한국동물위생학회지
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• 제25권2호
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• pp.127-133
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• 2002

The case reports for clostridium type A enterotoxemia in Formosan deer have rarely been reported. This paper describes a natural case of type A enterotoxemia in farmed Formosan deer in Cheongwon-gun. A dead, male 10-month-old Formosan deer was submitted to Chungbuk Livestock and Veterinary Research Institute, March 24, 2001 and examined. That deer was fed with assorted grain feed, oak leaves, acorn and bean curd. Grossly there was no visible external change. Despite of the carcass being examined within 12 hours of death, there was a quite degree of posonortem decomposition. There was severe hemorrhage in the serosa of abomasum and small intestine. Much blood tinged and watery contents were contained in those organs. Also there were severe swelling of spleen, some red foci in hepatic parenchyma. Microscopically there were severe congestion and hemorrhage in mucosa submucosa, muscular layer, and serosa of abomasum and small intestine. Also spleen and pancreas showed severe Congestion and hemorrhage. There were multifocal hemorrhage with hepatic necrosis in periportal area and focal mononuclear cell deposition in sinusoid. In bacterial culture for small intestine, Cl perfringens was isolated. By toxin typing for the strain, that had $\alpha$ -toxin belonged to type A. In electronmicroscopy for feces, no vims particle was detected. Considering clinical signs, gross lesions, microscopic lesions, bacterial culture, and toxin typing of the isolate, this case was diagnosed as enterotoxemia by Cl perfringens type A.

• 대한기계학회논문집A
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• 제24권9호
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• pp.2361-2370
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• 2000

The introduction of inexpensive cylinder pressure sensors provides new opportunities for precise engine control. This paper presents a control strategy of spark advance based upon cylinder pressure of spark ignition engines. A location of peak pressure(LPP) is the major parameter for controlling the spark timing, and also the UP is estimated, using a multi-layer feedforward neural network, which needs only five pressure sensor output voltage samples at -40˚, -20˚, 0˚, 20˚, 40˚ after top dead center. The neural network plays an important role in mitigating the A/D conversion load of an electronic engine controller by increasing the sampling interval from 10 crank angle(CA) to 20˚ CA. A proposed control algorithm does not need a sensor calibration and pegging(bias calculation) procedure because the neural network estimates the UP from the raw sensor output voltage. The estimated LPP can be regarded as a good index for combustion phasing, and can also be used as an MBT control parameter. The feasibility of this methodology is closely examined through steady and transient engine operations to control individual cylinder spark advance. The experimental results have revealed a favorable agreement of individual cylinder optimal combustion phasing.

• Transactions on Electrical and Electronic Materials
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• 제16권4호
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• pp.212-220
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• 2015

We investigated nanotextured Si solar cells using the silver-assisted chemical etching process. The nanotexturing process is very sensitive to the concentration of chemical etching solution. The high concentration process results in a nanowire formation for the nanosurfaces and causes severe surface damage to the top region of the micropyramids. These nanowires show excellent light absorption in photoreflectance spectra and radiative light emission in photoluminescence spectra. However, the low concentration process forms a nano-roughened surface and provides high minority carrier lifetimes. The nano-roughened surfaces of the samples show the improved electrical cell properties of quantum efficiency, conversion efficiency, and cell fill factor due to the reduction in the formation of the over-doped dead layer.

• 한국균학회지
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• 제26권1호통권84호
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• pp.78-85
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• 1998

전국 각지에서 채집한 사멸곤충에서 분리한 곤충 기생성 진균이 생산하는 살충성 생리활성물질을 탐색한 결과 곰팡이 분리주 CNAB-63 균주가 목화진딧물과 점박이응애 모두에 대해 다른 분리균주들보다 비교적 높은 살충효과를 보인 바, 본 균주가 생산하는 살충성분을 각종 chromatography로 분리 정제하였다. 정제된 활성물질 CNAB는 점박이응애에서 66.59%, 목화진딧물에서 52.96%의 살충효과를 보였으며, 그 외에도 온실가루이에 살충효과를 보였으나 배추좀나방에는 미미한 살충효과를 보였다. 한편 활성물질 CNAB는 $100\;{\mu}g/disk$ 농도에서 곰팡이, 효모, 세균류에 전혀 항균활성을 보이지 않았다.