• KSBB Journal
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• 제8권2호
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• pp.97-103
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• 1993

세포질 유전형질의 도입을 성공적으로 수행코자 세질 웅성 불임(eMS; cytoplasmic male sterili­t ty) 계통의 담배 MS(male sterility) Burley 21의 callus tissue에서 cytoplast를 분리시키고 이와 Ni­c cotiana tabacum Burley 64의 mesophyll protoplast 를 PEG방법에 의한 세포융합으로 cybrid cell올 유도할 수 있었다. cytoplast의 분라는 density gradient solution의 osmolarity를 일정하게 하는 것보다 gradient간의 차이가 더 효과적이였으며 분리된 cytoplast의 양은 재료로 이용된 protoplast의 20-30% 정도를 나타 내었다. 또한 cytoplast와 protoplast의 융합은 P PEG농도 50%에셔 효과적이었다.

• 미생물학회지
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• 제25권1호
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• pp.23-27
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• 1987

바이로이드 RNA 분자를 포함한 저분자량의 식물성 RNA 분자에 대해서 0M부터 8M 까지의 요소구배를 가진 폴리아크릴아미드켈을 이용하여 전기영동적 이동성을 조사하였다. 막대모양의 바이로이드 RNA 분자는 요소구배 겔에서 전반적으로 다른 저분량의 식물성 RNA들과 마찬가지로 요소구배에 수직인 방향으로 비슷한 수준의 전기영동적 이동성을 보여주었다. 이와 달리 고리모양의 바이로이드 RNA 분자는 요소구배 겔에서 고농도의 요소구배 부분에서 보다도 저 농도의 요소구배 부분에서 더 빠르게 이동하였다. 따라서 고리모양의 바이로이드 RNA 분자는 요소구배 겔의 중간부분에서 막대모양의 바이로이드 분자의 밴드를 가로 지르는 기울기를 가진 특이한 전기영동적 이동을 나타내었다. 결과적으로 고리모양의 바이로이드 RNA 분자의 전기영동적 이동성은 0M 8M의 요소구배를 가지는 바이로이드 RNA 분자의 변성겔에서 주로 요소의 농도에 따라서 영향을 받는 것으로 보인다.

• Elastomers and Composites
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• 제34권5호
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• pp.383-390
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• 1999

Functionally graded polyurethane elastomers PUEs/grad. Poly(dimethylammoninum ethylacrylate bromide)(PDMAEA) were prepared by the method of electrophoresis. Results of elemental analysis showed that concentration of PDMAEA had gradient across the thickness(2mm) of the base PUEs. The modified PUEs(PUEs/grad. PDMAEA) containing high concentration of PDMAEA displayed low degree of swelling in benzene which was poor solvent for PDMAEA, and high degree of swelling in water which was good solvent. For the each layer of modified PUEs, glass transition temperature, dynamic storage modulus were stooled by DSC, Rheovibron DDV-IIC dynamic viscoelastomer. The chemomechanical properties of modified PUEs was explored by the electric-stimulus.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.243-246
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• 2002

Surfactant-enhanced electrokinetic remediation is an emerging technology that can effectively remove hydrocarbons from low-permeability soils. In this study, the electrokinetic remediation using APG(alkyl polyglucoside) was conducted for the removal of phenanthrene from kaolinite. APG, which was an environmentally compatible and non-toxic surfactant, was used at concentrations of 5, 15, and 30g/1 to enhance the solubility of phenanthrene. Also an electrolyte solution was used for considering a relation between electrical potential gradient and removal efficiency of phenanthrene. When the electrolyte solution was used, it represented low electrical potential gradient, but the removal efficiency was lower than that of no electrolyte system. Removal efficiency of phenanthrene in EK process using surfactant solution depended on concentration of surfactant. Because surfactant increased the solubility and the mobility of phenanthrene, when surfactant concentration was high, high removal efficiency was observed.

• 한국진공학회지
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• 제7권s1호
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• pp.118-122
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• 1998

$Al_2O_x$(0$Al_2O_3$ gradient coatings were formed by evaporating pure aluminium(99.9%) in $O_2$ environment with an IBAD facility, 12keV $Ar^+$ was used to irradiate the coatings simultaneously during the deposition. Sample's composition and depth profile were analysed by RBS and AES measurement, and their microhardness and porosity property were also measured in the experiment. Results show that, the oxygen concentration in the deposited coatings has a nearly linear relationship with the inputting gas flow before $O_2$ partial pressure in the target chamber reaches $1.2\times10^{-3}$ mbar under which stoichiometric $Al_2O_3$ could be formed; and sample's microhardness and porosity property is affected significantly by the oxygen concentration in the coatings.

• The Korean Journal of Physiology
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• 제1권2호
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• pp.157-168
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• 1967

The entry of antipyrine and urea from the peritoneal cavity of rabbit into organ tissue and blood plasma was studied. Two hundred mg of antipyrine plus 300 mg of urea in 10 ml Ringer's solution was injected into the peritoneal cavity of anesthetized rabbit. The injection was made from above of a rabbit kept tying right side down and it enabled part of the abdominal organs (liver, intestine, kidney) was immersed in the injected solution and kept high concentration gradient throughout the experimental period. The remaining part of the organs was revered only by a thin film of the test solution. Subsequently, in this part of the organs the concentration gradient of the diffusible substances during entry was presumed to decrease as time elapsed. Four pieces of the liver tissue were taken namely, the right superficial, right deep, left superficial and left deep portions. Two were taken from the small intestine, one from the portion which was immersed in. the fluid and the other from that above the fluid mass. Both kidneys were separately analyzed. As a remote organ the gastrocnemius muscle was taken from the right leg of the animal. The intervals which were the time periods elapsed after injections were 5,7,10,15 or 30 minutes. At each point 5 animals were sacrificed and the concentrations of the test substances in the tissue water were measured. The results obtained were as follows. 1. In the liver the right portion which was immersed in the fluid showed higher concentration if the test substances than the left portion and the superficial region exceeded the deep region. The concentrations diminished as the time elapsed after infusion, particulary in the case of antipyrine, suggesting circulatory removal of the substances. In urea such decreasing tendency of the concentration was not obvious, and suggested slower removal rate of it as compared with that of antipyrine. 2. In the small intestine there was no regional difference in the concentration of the test substances. Because of the intestinal motility different portions of the intestine were seemed to have bathed in the fluid of the same concentration. In general the concentrations in the intestinal wall exceeded those of the liver, suggesting a slower removal rate than in the latter. 3. In the kidney the accumulation of the endogenous urea was predominant, and the accumulating mechanism in the renal tissue went on during the period of the experiment. Therefore it revealed increasing tendencies as the time elapsed. The penetration of the test substances in this organ from the peritoneal cavity seemed to be slower than in other abdominal organs, namely liver or small intestine. Part of the test substances in the kidney were obviously brought by the blood stream. 4. Rapid exponential decay of the concentration of antipyrine and of the osmolality of the peritoneal fluid was attributed to the extensive removal through the whole dimension of the peritoneal surface, and the remote organ such as the gastrocnemius muscle attained a fairly close value to that of the abdominal organs in less than 30 minutes. The factors which related to the absorption rate were discussed. They were the concentration gradient, permeability and the regional perfusion rate.

• 한국식물병리학회지
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• 제3권4호
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• pp.239-244
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• 1987

감자 걀쪽바이로이드(PSTV) RNA분자를 포함한 저분자량의 식물성 RNA분자에 대해서 0M부터 8M까지의 요소농도구배를 가진 폴리아크릴아마이드겔을 이용하여 1/40, 1/10로 희석한 완충액조건과 $17^{\circ}C,\;37^{\circ}C,\;57^{\circ}C$의 온도조건에서 전기영동을 실시하였다. 바이로이드의 RNA분자가 환상과 선상의 두가지 분자로 나뉘어지는 변성조건에서는 1/40로 희석한 TBE완충액을 포함하는 요소농도구배겔을 $57^{\circ}$에서 전기영동을 실시하는 것이 효과적이었다. 변성된 환상의 바이로이드분자에 대한 전기 영동적 이동성은 주로 요소의 농도에 따라 영향을 받는 것으로 보이는데, 이와 더불어 저 농도의 TBE완충액이 요소농도구배겔에서 환상과 선상바이로이드분자 사이에서 전기영동적 분리를 증가시켜 주었다.

• ETRI Journal
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• 제42권1호
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• pp.129-137
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• 2020

All-solid-state batteries are promising energy storage devices in which high-energy-density and superior safety can be obtained by efficient cell design and the use of nonflammable solid electrolytes, respectively. This paper presents a systematic study of experimental factors that affect the electrochemical performance of all-solid-state batteries. The morphological changes in composite electrodes fabricated using different mixing speeds are carefully observed, and the corresponding electrochemical performances are evaluated in symmetric cell and half-cell configurations. We also investigate the effect of the composite electrode thickness at different charge/discharge rates for the realization of all-solid-state batteries with high-energy-density. The results of this investigation confirm a consistent relationship between the cell capacity and the ionic resistance within the composite electrodes. Finally, a concentration-gradient composite electrode design is presented for enhanced power density in thick composite electrodes; it provides a promising route to improving the cell performance simply by composite electrode design.

• The Korean Journal of Physiology and Pharmacology
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• 제1권5호
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• pp.537-546
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• 1997

It has been postulated that the intracellular taurine is co-transported with $Na^+$down a concentration gradient and prevents the intracellular accumulation of sodium. It is therefore, expected that an elevated level of intracellular taurine prevents the sodium-promoted calcium influx to protect the cellular damages associated with sodium and calcium overload. In the present study, we evaluated the effects of intra- and extracellular taurine on the myocardial $Na^+$and$Ca^{++}$ contents and the cardiac functions in isolated rat hearts which were loaded with sodium by monensin, a $Na^+-ionophore$. Monensin caused a dose-dependent increase in intracellular $Na^+$ accompanied with a subsequent increase in intracellular $Ca^{++}$ and a mechanical dysfunction. In this monensin-treated heart, myocardial taurine content was decreased with a concomittent increase in the release of taurine. The monensin-induced increases in intracellular $Na^+$, $Ca^{++}$ and depression of cardiac function were prevented in the hearts of which taurine content had been increased by high-taurine diet. Conversely, in the hearts of which taurine concentration gradient had been decreased by addition of taurine in the perfusate, the monensin-induced increases in $Na^+$, $Ca^{++}$ and functional depression were accelerated. These results suggest that taurine, depending on the intra-extracellular concentration gradient, can affect intracellular sodium and calcium concentrations, and that an increased intracellular taurine may play a role in protection of myocardial dysfunction associated with the sodium and calcium overload.

• 대한기계학회논문집B
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• 제35권6호
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• pp.633-640
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• 2011

본 연구에서는 고온의 미소농도구배 조건에서의 에지화염의 안정화 및 화염 강도 변화를 실험적으로 관찰하였다. 실험 연소기는 크게 혼합기가 투입되는 슬롯과 석영 채널 및 채널 내부 가열을 위한 추가적인 예혼합 연소기로 구성되어 있다. 실험의 정확성을 위해 각 경계 조건에 대한 정량적인 검증 절차가 수행되었다. 결론적으로 연료 농도 구배의 정량적인 제어와 질소 희석비율을 조절하여 고온의 조건에서도 에지화염을 임의의 위치에 안정화 시킬 수 있었다. 에지화염 내부에 존재하는 확산화염의 화염 강도가 채널 내부의 온도증가에 따라 증가하고 질소의 희석비율 증가에 따라 감소하는 것을 보였다. 연료에 따른 화염 강도 변화를 살펴본 결과 프로판의 경우가 메탄에 비해 강도 변화율이 큰 것을 알 수 있었다.