• Horticultural Science & Technology
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• v.32 no.3
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• pp.318-329
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• 2014

In order to gain insight into the physiological responses of plants to high temperature stress, the effects of temperature on Chinese cabbage (Brassica campestris subsp. napus var. pekinensis cv. Detong) were investigated through analyses of photosynthesis and chlorophyll fluorescence under 3 different temperatures in the temperature gradient tunnel. Growth (leaf length and number of leaves) during the rosette stage was greater at ambient $+4^{\circ}C$ and ambient $+7^{\circ}C$ temperatures than at ambient temperature. Photosynthetic $CO_2$ fixation rates of Chinese cabbage grown under the different temperatures did not differ significantly. However, dark respiration rate was significantly higher in the cabbage that developed under ambient temperature relative to elevated temperature. Furthermore, elevated growth temperature increased transpiration rate and stomatal conductance resulting in an overall decrease of water use efficiency. The chlorophyll a fluorescence transient was also considerably affected by high temperature stress; the fluorescence yield $F_J$, $F_I$, and $F_P$ decreased considerably at ambient $+4^{\circ}C$ and ambient $+7^{\circ}C$ temperatures, with induction of $F_K$ and decrease of $F_V/F_O$. The values of RC/CS, ABS/CS, TRo/CS, and ETo/CS decreased considerably, while DIo/CS increased with increased growth temperature. The symptoms of soft-rot disease were observed in the inner part of the cabbage heads after 7, 9, and/or 10 weeks of cultivation at ambient $+4^{\circ}C$ and ambient $+7^{\circ}C$ temperatures, but not in the cabbage heads growing at ambient temperature. These results show that Chinese cabbage could be negatively affected by high temperature under a future climate change scenario. Therefore, to maintain the high productivity and quality of Chinese cabbage, it may be necessary to develop new high temperature tolerant cultivars or to markedly improve cropping systems. In addition, it would be possible to use the non-invasive fluorescence parameters $F_O$, $F_V/F_M$, and $F_V/F_O$, as well as $F_K$, $M_O$, $S_M$, RC/CS, ETo/CS, $PI_{abs}$, and $SFI_{abs}$ (which were selected in this study), to quantitatively determine the physiological status of plants in response to high temperature stresses.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.2
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• pp.3-11
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• 2011

Evaluation of cube roots in characteristic three finite fields is required for Tate (or modified Tate) pairing computation. The Hamming weights (the number of nonzero coefficients) in the polynomial representations of $x^{1/3}$ and $x^{2/3}$ determine the efficiency of cube roots computation, where $F_{3^m}$is represented as $F_3[x]/(f)$ and $f(x)=x^m+ax^k+b{\in}F_3[x]$ (a, $b{\in}F_3$) is an irreducible trinomial. O. Ahmadi et al. determined the Hamming weights of $x^{1/3}$ and $x^{2/3}$ for all irreducible trinomials. In this paper, we present formulas for cube roots in $F_{3^m}$ using the shifted polynomial basis(SPB). Moreover, we provide the suitable shifted polynomial basis bring no further modular reduction process.

• Journal of the Korean Magnetics Society
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• v.5 no.2
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• pp.119-122
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• 1995

We have measured the magnetic susceptibilities of a CuF/sub 2/ .center dot. 2H/sub 2/O sample by means of the SQUID(superconducting quantum interference device) at the magnetic fields of 0.5 T and 1 mT, in the temperature range 5-300 K. The sample was found to contain some nonmagnetic calcium and magnesium impurities by the elemental analysis. Our measurements differ from known results for pure Cu F/sub 2/ .center dot. 2H/sub 2/O and are well explained by the effect of the nonmagnetic impurities in our sample. The purity of our sample derived from the temperature dependence of the susceptibilities was compared with that from the elemental analysis.

• Journal of Surface Science and Engineering
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• v.53 no.2
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• pp.59-66
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• 2020

Effects of Na₂SiO₃ concentration added into 0.1 M NaOH + 0.05 M NaF solution on the formation behavior and properties of PEO films on AZ91 Mg alloy were investigated under 1200 Hz of alternating current (AC) by voltage-time curves, in-situ observation of arc generation behavior and measurements of film thickness, surface roughness and micro vickers hardness. In the absence of Na₂SiO₃ in the 0.1 M NaOH + 0.05 M NaF solution, about 4 ㎛ thick PEO film was formed within 1 min and then PEO film did not grow but white spots were formed by local burning. Addition of Na₂SiO₃ up to 0.2 M caused more increased formation voltage and growth of PEO film with uniform generation of arcs. Addition of Na₂SiO₃ from 0.2 M to 0.4 M showed nearly the same voltage-time behavior and uniform arc generation. Addition of Na₂SiO₃ more than 0.5 M resulted in a decrease of formation voltage and non-uniform arc generation due to local burning. PEO film growth rate increased with increasing added Na₂SiO₃ concentration but maximum PEO film thickness was limited by local burning if added Na₂SiO₃ concentration is higher than 0.5 M. Surface roughness of PEO film increased with increasing added Na₂SiO₃ concentration and appeared to be proportional to the PEO film thickness. PEO film hardness increased with increasing added Na₂SiO₃ concentration and reached a steady-state value of about 930 H_V at more than 0.5 M of added Na₂SiO₃ concentration.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.44-44
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• 2021

본 연구는 제주지역의 골프 코스에서 하절기 고온기간에 온도의 상승을 비롯한 다양한 환경변화로 인하여 생육 장애가 심한 한지형 잔디인 perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), creeping bentgrass (Agrostis palustris Huds.) 3종에 대하여 엽록소형광과 엽록소지수를 측정하여 골프 코스와 스포츠 필드에서 잔디 선정과 관리를 위한 기본적인 정보를 얻기 위하여 수행하였다. F_o 값은 3종 모두 하절기 초기에는 낮고 후기에 다소 증가하는 양상을 보였다. 그러나, perennial ryegrass의 경우는 하절기 초기와 후기 간의 F_o 값의 변화가 컸으며, 특히, 후기에 F_o 값은 다른 2종 월등하게 보다 높았다. F_m 값은 3종 모두 하절기 초기에는 낮고 하절기 후기에 증가하였으나 3종 간의 차이는 크지 않았다. 광계 II의 광화학적 효율의 척도인 F_v/F_m 값은 3종 모두에서 하절기 초기에 낮고, 후기에 다소 증가하는 양상을 보였으나, 하절기 후기에 Kentucky bluegrass와 creeping bentgrass는 perennial ryegrass에 비해 F_v/F_m 값이 다소 높아 하절기 고온에서도 보다 더 잘 적응하는 것으로 보인다. 엽록소지수는 perennial ryegrass와 Kentucky bluegrass에서는 뚜렷하게 하절기 초기에는 낮고 후기에 높은 양상을 보였으나, creeping bentgrass는 조사기간 내내 낮은 상태를 유지하였다. 이상의 결과로부터 Kentucky bluegrass가 하절기 후기의 고온이나 빈번한 강우에 의한 습한 조건에 가장 강하고, perennial ryegrass가 가장 취약한 것으로 사료된다.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.239-244
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• 2007

In order to investigate the effect of fluorine ion in the $Li_{1-x}FeO_2Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8) cathode material, it was synthesized $Li_{1-x}FeO_{2-y}F_y-Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8, $0.05{\le}y{\le}0.15$) cathode materials at $350^{\circ}C$ for 10hrs using solid-state method. $Li_{1-x}FeO_{2-y}F_y-Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8, $0.0{\le}y{\le}0.1$ was composed many large needle-like particles of about $1-1.5\;{\mu}m$ and small particles of about 50-100 nm, which were distributed among the larger particles. However, $Li_{1-x}FeO_{1.85}F_{0.15}-Li_xMnO_2$ material showed slightly different particle morphology. The particles of $Li_{1-x}FeO_{1.85}F_{0.15}-Li_xMnO_2$ were suddenly increased and started to be a spherical type of particle shape. $Li/Li_{1-x}FeO_{1.9}F_{0.1}-Li_xMnO_2$ cell showed a high initial discharge capacity of 163 mAh/g and a high cycle retention rate of 95% after 50 cycles. The initial discharge capacity of $Li/Li_{1-x}FeO_{2-y}F_y-Li_xMnO_2$ ($0.05{\le}y{\le}0.15$) cells increased according to the increase of F content. However, the cycleability of this cell was very rapidly decreased when the substituted fluorine content is over 0.1. We suggested that too large amount of F ion fail to substitute into the $Li_{1-x}FeO_2-Li_xMnO_2$ structure, which resulted in the severe decline of battery performance.

• Journal of the Korean Electrochemical Society
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• v.3 no.4
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• pp.235-240
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• 2000

Screen-printing and doctor blade method were investigated and proposed as an electrode coating process for high power capacitor. CV measured from the amorphous $MnO_2$ electrode prepared by screen-printing shows closer to ideal capacitor characteristics. Specific capacitances calculated from CVs with potential scan rate of 50mV/s were 5.8, 81.8, and 172.0 F/g for electrode thickness of $140{\mu}m,\;24{\mu}m,\; 3{\mu}m$, respectively. Assumed that utilization of active $MnO_2$ in electrode of screen-printing is $100\%$, those were $3.4\%$ in one of paste method and $47.6\%$ in one of doctor blade method. The screen-printing can be good technique to coat thin film on current collector for high power application.

• Korean Journal of Organic Agriculture
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• v.4 no.1
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• pp.45-58
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• 1995

This paper studied production characteristics of organic farming products and analyzed management income and production cost of organic farming(rice). In order to analyze these points actually, this study was focused on pruduction activities of a producers' organization, Pulmoo Cooperatives in Hong-Dong Myun, Hong-Seong Region, Chung Nam Province. So the following results were obtained : In 1994, output level and an income rate of rice per unit area(10a) which was produced in organic farming method(O.F.M) was higher than those of general farming method(G.F.M) as about 5%, 7.4%. And management income size of the former was 1.8 times as large as that of the latter. But rice production cost of O.F.M was 1.93 times as much as that of G.F.M, particularily in labor cost and farming equipment cost, light and heat expenses, many other material costs. For the progress of organic farming O.F.M and equipmets should be developed much more, for example, the technics of prevetion against damages by blight and harmful insects and improvement of varieties, natural pesticides, agricultual application of microorganisim, construction of compost heat factory, etc. Since these technics and establishments have taken on the public goods, the development of those should be supported by government.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.7
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• pp.604-610
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• 2003

The effects of sintering additives such as B $i_2$ $O_3$ and $V_2$ $O_{5}$ on the microwave dielectric and sintering properties of (Z $n_1$$_{-xM}$ $g_{x}$)Ti $O_3$ system were investigated. Highly dense samples were obtained for (Z $n_{0.8}$M $g_{0.2}$)Ti $O_3$ at the sintering temperature range of 870~90$0^{\circ}C$ with B $i_2$ $O_3$ and $V_2$ $O_{5}$ additions of 〈1 wt.%, respectively. The microwave dielectric properties of (Z $n_{0.8}$M $g_{0.2}$)Ti $O_3$ with 0.45 wt.%B $i_2$ $O_3$ and 0.55 wt.% $V_2$ $O_{5}$ sintered at 90$0^{\circ}C$ were as follows : Q$\times$ $f_{o}$ = 50,800 GHz, $\varepsilon$$_{r}$ = 22, and $\tau$$_{f}$ = -53 ppm/$^{\circ}C$. In order to improve temperature coefficient of resonant frequency, Ti $O_2$ was added to the above system. The optimum amount of Ti $O_2$ was 15 moi.% when sintered at 87$0^{\circ}C$, at which we could obtain following results: Q$\times$ $f_{o}$ = 32,800 GHz, $\varepsilon$$_{r}$ = 26, and$\tau$$_{f}$ = 0 ppm/$^{\circ}C$.EX>.EX>.EX>.EX>.EX>.EX>.EX>.

• Journal of the Korean Electrochemical Society
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• v.16 no.3
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• pp.162-168
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• 2013

$Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn) nano-composite is a promising cathode material for xEV application due to its high theoretic capacity. However high voltage operating system of $Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn) has worked as a hurdle in its application because of the inherent demerits, such as cycle life degradation and gas evolution. In order to enhance cell performance of $Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn)/graphite cell, we examined electrolyte mainly composed of FEC, fluroalkyl ether and $LiPF_6$ (F-based EL). F-based EL showed much better discharging retention ratio than 1.3 M $LiPF_6$ EC/EMC/DMC (3/4/3, v/v/v) (STD). Furthermore gas evolution, especially CO and $CO_2$ during $60^{\circ}C$ storage for 30 days was dramatically reduced owing to thermal stable SEI formation effect of F-based EL.