• Applied Biological Chemistry
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• v.43 no.4
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• pp.236-240
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• 2000

Correlations between mitochondrial respiration, glycolysis activity and overall growth activity of rice (Oryza sativa: cv. Dasan) seedlings during low temperature exposure were studied in order to provide insights into the underlying mechanism for the primary phase of chilling injury in plants. Among cellular membranes involved in energy metabolism, only the mitochondrial inner membrane showed not only physical phase transition at ca. $13^{\circ}C$, as monitored by ESR spin label, but also functional phase transition at the same temperature, as assessed by cytochrome c oxidase activity. The main regulatory enzyme of glycolysis, phosphofructokinase, in situ did not suffer phase transition of its activity at least in the $4{\sim}27^{\circ}C$ range. Low temperature caused a significant accumulation of glucose 6-phosphate (G6P) and fructose 6-phosphate (F6P), which disappeared almost completely on rewarming of the seedlings. Temperature profiles of the steady state levels of G6P and F6P revealed the inflection point appearing at around phase transition temperature of the mitochondrial membrane. The results conform to our previous proposition on the mechanism for the early stage events of chilling injury that the accumulation of glycolytic metabolites in cells due to metabolic imbalance at low temperature gives rise to an excess supply of electrons during rewarming period, which, in turn, results in overproduction of active oxygen in mitochondria.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.04a
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• pp.70-71
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• 1998

1. 서론 : 상업적으로 널리 사용되고 있는 cellulose acetate, polysulfone 등과 같은 막 소재는 유기용매에 대한 화학적 안정성이 떨어지므로 새로운 막분리 소재가 필요로 되고 있다. 기계적 강도, 열적 안정성이 뛰어난 Polyimide 는 거의 모든 종류의 유기용매에 대한 안정성이 우수하여 비수계용 한외여과의 분야에서 높은 잠재력을 지니고 있다. 그러나 Polyimide 는 대부분의 유기용매에 녹지 않으므로 상전환방법에 의한 비대칭막을 제조하기가 어려웠다. (생략)

• The Optical Journal
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• s.103
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• pp.57-61
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• 2006

해를 거듭할수록 아시아에서 가장 유력한 사진 영상관련 전시회로 자리매김하고 있는 '서울국제사진영상기자재전/디지털영상전(PHOTO & IMAGING)'이 2006년 5월 18일부터 21일까지 4일간 서울 삼성동 코엑스 태평양홀에서 개최된다. 한국광학기기협회, 한국사진기재협회, 코엑스가 공동주최하고 산업자원부, PPA(Professional Photographers of America), SLRCLUB, 대한사진영상신문이 후원하는 본 전시회는 올해로 15회째를 맞이한 가운데 20개국 250여개의 사진 관련 모든 분야의 기자재 업체들이 각 분야의 전문화 된 다양한 제품들을 전시한다. 또한 수많은 전문 · 취미 사진가들을 포함한 6만 여명의 사진애호가들의 관심이 집중 될 것으로 기대를 모으고 있다.

• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1181-1187
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• 1999

PZT(53/47) precursor 1M sols were prepared using a diol based Sol-Gel process, and thin films were deposited by spin coating onto Pt/Ti/$SiO_2$/Si substrates. With a single coating, final film thickness of aproximately 0.9${\mu}m $ was achieved from diol-based PZT sol. Since PZT crystallized in a ferroelectric perovskite phase from an intermediate nonferroelectric pyrochlore phase, the effects of the presence of perovskite PZT seeds on the phase transformation of PZT were investigated. Seeded PZT films were prepared from the seeded PZT 1M sols in which seeds with less than 0.2${\mu}m $ in size and 1wt% were dispersed in n-propanol before mixing with the PZT stock solution. The seeding effects were confirmed by the fact that the formation temperature of perovskite phase decreased by 50$^{\circ}C$ with less than 1wt% seeds.

• Membrane Journal
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• v.31 no.1
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• pp.67-79
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• 2021

Mesoporous polystyrene (PS) and polyethersulfone (PES) membranes have been fabricated by reverse-thermally induced phase separation (RTIPS) process, using flash freezing. The mesoporous pores can be created by the nano-scaled phase separation induced by the formation and growth of solvent crystals in the dope solution in RTIPS process. RTIPS process has been characterized through analysis on the enthalpy change in the solvent of the dope solution, the morphology of the membrane fabricated with different polymer content, and the pore size distribution and its standard deviation of pore size of the membrane with polymer content via DSC, SEM, and BET, respectively. It is found that the kinetic aspect of the dope solution, i.e., the crystallization of solvent is a crucial factor to determine the structure of membrane fabricated in RTIPS rather than the thermodynamic aspect of the dope solution.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.63-69
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• 2022

Vanadium dioxide shows a unique and interesting property of metal-insulator transition, which has attracted great attention from the viewpoints of fundamental materials science and industrial applications. In this study, the effect of Mg and W addition on the metal-insulator transition of VO₂ were investigated for the bulk materials that are prepared by spark plasma sintering. The X-ray diffraction analysis of the sintered specimens revealed that the lattice parameters barely change, and the secondary phases are present. The transition temperature of MIT appears in the range of 64.2-64.6℃, regardless of the impurity element and content. On the other hand, the addition of Mg and W alters the electrical conductivity, i.e., the electrical conductivity increases by a factor of up to 2.4 or decrease by a factor of up to 57.4 depending on the impurity type and its content. The thermal conductivity showed the values of 1.8~2.5 W/m·K below the transition temperature, and the values of 1.9~2.8 W/m·K above the transition temperature. These changes in electrical and thermal conductivities can be attributed to the combination of the change in charge carrier density, the impurities as scattering centers, and the change in microstructures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.210-211
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• 2005

[ $(K_{0.5}Na_{0.5})NbO_3$ ](KNN) 세라믹스의 소결 특성과 압전 특성을 높이기 위해 B-site에 Sb를 치환하여 Sb함량에 따른 특성을 측정 하였다. Sb 의 함량을 0mol $\sim$ 0.1mol 까지 첨가한 결과 소결 밀도는 Sb의 첨가량이 많아질수록 증가하다 Sb-0.08mol에서 4.40g/$cm^3$으로 가장 높은 밀도를 가졌으며, 여기서의 전기기계 결합 계수가(Kp) 0.45로 높은 값을 나타내었다. 상전 이 온도는 375$^{\circ}C$로 순수한 KNN 의 420$^{\circ}C$ 보다 약 45$^{\circ}C$정도 떨어졌으나 orthorhombic에 서 tetragonal 로 바뀌는 전이 온도는 KNN이 220$^{\circ}C$, KNNS 가 225$^{\circ}C$로 크게 변하지 않았다.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1916-1920
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• 2010

영상수위계는 카메라에 의해서 수위표를 촬영하여 촬영된 영상을 처리하여 수위값으로 변환하여 자동적으로 수위를 측정하는 장비이다. 이 수위계는 기존 수위측정 장비인 부자식, 압력식, 기포식, 초음파식, 레이다식과는 달리 수위표를 촬영한 영상으로부터 수위를 직접 눈으로 확인할 수 있는 장점이 있다. 이로 인해 영상자료로부터 측정된 수위를 검증할 수 있어 수위측정의 정확도를 향상시킬 수 있다. 그리고 수위표 영상과 더불어 관측지점 주변의 전체 영상을 동시에 촬영하여 실시간으로 전송하기 때문에 홍수시 하천 상황에 대한 모니터링 목적으로 사용될 수 있다. 영상수위계 시스템은 크게 메인제어기, 전원부, 서버부 및 카메라부로 구성되어 있다. 현재 운영되고 있는 시스템은 전원장치 리셋시 전 시스템을 리셋해야하고, 상전 단전시 전 시스템이 off된다. 그리고 별도의 통신모듈을 사용하여 장비간 통신이 이루어지고 있다. 또한 카메라부에는 렌즈와 팬/틸트를 제어하기 위한 별도의 장비가 포함되어 있고, 백색 LED 조명이 사용되어 야간에 수위인식주기마다 조명이 on/off 되고 있다. 위와 같은 전원장치의 운영으로 시스템을 안정적으로 운영할 수 없다. 그리고 수위 오인식을 최소화하기 위해서는 연속적인 수위 인식이 필요하지만, 백색 LED조명과 1초에 2프레임을 캡쳐하는 비디오 캡쳐방식에 의해 시스템을 상시로 운영하는 것이 곤란하다. 현재 운영 중인 영상수위계를 안정적으로 운영할 수 있도록 장비별로 제어가 가능하도록 전원 제어장치를 개발하였고, 상전 단전시 최소 30분 정도 전원을 유지할 수 있도록 무정전전원장치(UPS)를 설치하였으며, 측정자료의 저장장치를 하드디스크 타입에서 Flash SSD 메모리 타입으로 교체하였다. 또한 영상수위계 시스템을 상시 운영할 수 있도록 백색 LED조명을 적외선 LED조명으로 교체하였고, 1초에 1회 수위를 인식하도록 수위인식주기와 1초에 25프레임 캡쳐할 수 있도록 비디오 캡쳐방식을 개선하였다. 위와 같은 시스템의 개선으로 시스템을 안정적으로 운영할 수 있게 되어 시스템 고장에 의해 발생하는 수위 결측을 감소시킬 수 있고, 시스템의 상시 운영으로 수 위 오인식을 최소화시킬 수 있을 것으로 판단된다.

• Journal of the Korean Magnetics Society
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• v.8 no.4
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• pp.179-184
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• 1998

Colossal magnetoresistance is closely related to (but is not) the abrupt change of electrical resistivity in the vicinity of Curie temperature, which is caused by the temperature dependent paramagnetic-ferromagnetic phase transition and concurrent change of electrical conducting mechanism. A resistivity-temperature equation is presented to fully describe the overall behavior, especially the abrupt change. The main ingredients of the equation are a simple effective media theory and a function for the temperature dependent fraction of ferromagnetic phase. The model fits very well to the measured resistivity-temperature curve of $La_{0.7}Ca_{0.3}MnO_3$.

• Journal of Sericultural and Entomological Science
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• no.11
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• pp.1-14
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• 1970

The following results were obtained by surveying the productivity of mulberry fields in Korea. 1. The productivity of mulberry field per 10a in which cocoon can be yield belongs to the range of 9.8∼105kg, and among them the productivity of 20 to 60kg was chiefly distributed. And their average was 50.2kg. 2. In general, the larger the mulberry field in scale per a person is, the lower the productivity of it is, but about 6.6 ares per a person was estimated to be economic scale for high productivity. 3. As far as the texture of soil is concerned, sandy-loam and loam contained a capacity of higher productivity while others like clay and sand that of lower productivity, And the depth of surface soil must be at least 50cm, although 70cm's depth of surface sail could bring about high productivity. 4. Fertilization of 900kg's compost on planting and 1,200kg's that after planting could enhance the productivity, because the use of compost have a positive relation to the productivity. 5. The greater the number of farmer's domestic animals is as a source of organic matter the higher the productivity is. 6. In the case of fertilization of 1,200kg compost, the amount of 20kg's nitrogen per 10 ares as chemical manure was best for high productivity. However, fertilization of 14.7kg's nitrogen as average amount of that, which is far below the standard amount, had been a factor to reduce the productivity of mulberry field. 7. In pruning the low-cut form resulted in high productivity, but as their shape become taller due to the lack of techniques, they were turned out to be non head pruning, thus to produce poor harvest of leaves. 8. The pure mulberry fields showed better productivity than others such as wide and narrow ridge planting and inter-crop planting. 9. As for the degree of planting density, at least 800 trees per 10 ares should be planted to increase the productivity, although the planting of 713 trees per 10 ares could be possible in case of the low stemmed pruning. 10. The hole and tranch in planting must be digged as wider and dipper as possible far the better growth of mulberry tree. 11. On the whole, varieties like NOsang and Y oung-cheun choowoo had a tendency of lower productivity.