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转铜/锌超氧化物歧化酶和抗坏血酸过氧化物酶基因甘薯的耐旱性

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植物生理与分子生物学学报 2006年第4期32卷 451-457页

作者：李筠邓西平郭尚洙田中净中国科学院教育部水土保持与生态环境研究中心黄土高原土壤侵蚀与旱地农业国家重点实验室韩国生物科学与生物技术研究所鸟取大学农学部

水分胁迫使转铜/锌超氧化物歧化酶基因(Cu/ZnSOD)和抗坏血酸过氧化物酶基因(APX)甘薯及未转基因甘薯中超氧阴离子(O-2·)、过氧化氢(H2O2)、丙二醛(MDA)含量和细胞膜相对透性增加,在相同条件下以上指标均为转基因甘薯低于未转基因甘薯;... 详细信息

水分胁迫使转铜/锌超氧化物歧化酶基因(Cu/ZnSOD)和抗坏血酸过氧化物酶基因(APX)甘薯及未转基因甘薯中超氧阴离子(O-2·)、过氧化氢(H2O2)、丙二醛(MDA)含量和细胞膜相对透性增加,在相同条件下以上指标均为转基因甘薯低于未转基因甘薯;而叶片含水量、净光合速率(Pn)和气孔导度(Gs)均下降,SOD和APX酶活性随胁迫程度的加重先增大后减小,胞间CO2浓度(Ci)则先减小后增大,在相同条件下转基因甘薯中以上指标均高于未转基因甘薯。这些结果表明:转入Cu/ZnSOD和APX基因使转基因甘薯清除活性氧的能力增强,在水分胁迫下能保持较高的叶片含水量和Pn,耐旱性得到提高。

关键词：水分胁迫活性氧光合作用转Cu/Zn SOD 和APX基因甘薯耐旱性

Microstructure and Mechanical Properties of TiB-Containing Al–Zn Binary Alloys

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Journal of Materials Science & Technology 2016年第7期32卷 653-659页

作者： sang-soo Shin Gil-Yong Yeom Tae-Yang kwak Ik-Min Park Department of Materials Science and Engineering Pusan National University Busan 609-735 Republic of Korea Liquid Processing & Casting Technology R&BD Group Korea Institute of Industrial Technology Incheon 21999 Republic of Korea

The microstructure and mechanical properties of newly developed Al-35Zn cast alloys with TiB refiner addition were evaluated by X-ray diffractometry, optical microscopy, and scanning electron microscopy coupled with energy dispersive spectrometry. The microstructure of these alloys featured α-Al den- drites surrounded by AI-Zn （α ＋ rI） eutectic structures. After the addition of TiB refiner, the alloy grain sizes decreased, and its morphology abruptly changed from dendritic to equiaxed grains. Such an im- proved microstructure of the modified alloys was accompanied by a significant increase in the tensile strength and elongation percentage compared to those of the AI-Zn or Zn-Al-based alloys. The results showed that with the increase of TiB content up to 0.05%, the morphology of α-Al dendrites and α ＋ T1 phases changed from coarse dendrite and lamellar structures into independent and fine ones. Based on these results, the effect of TiB refiner addition on the microstructure and mechanical properties of the AI-35Zn binary alloys was investigated.

关键词： Al-Zn(-Cu) alloyEutectic structureHigh strengthTiB2

A study on hydrogen uptake and release of a eutectic mixture of biphenyl and diphenyl ether

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Journal of Energy Chemistry 2020年第3期29卷 11-16页

作者： Munjeong Jang Byeong soo Shin Young Suk Jo Jeong Won Kang sang Kyu kwak Chang Won Yoon Hyangsoo Jeong Center for Hydrogen Fuel Cell Research Korea Institute of Science and Technology(KIST)5 Hwarang-ro 14-gilSeongbuk-guSeoul 02792Republic of Korea Divison of Energy and Environment Technology KIST SchoolKorea University of Science and Technology5 Hwarang-ro 14-gilSeongbuk-guSeoul 02792Republic of Korea Department of Chemical and Biological Engineering Korea UniversityAnam-ro 145Seongbuk-guSeoul 02841Republic of Korea School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology50UNIST-gilUlsan 44919Republic of Korea KHU-KIST Department of Converging Science and Technology Kyung Hee University26 Kyungheedae-roDongdaemun-guSeoul 02447Republic of Korea

Hydrogen storage in Liquid Organic Hydrogen Carrier(LOHC)systems is appealing for the safe storage and distribution of excess renewable energy via existing gasoline infrastructures to *** present the eutectic mixture of biphenyl and diphenyl ether of its first use as a LOHC *** material is hydrogenated with 99%selectivity without the cleavage of C–O bond,with commercial heterogeneous catalysts,which is confirmed by nuclear magnetic spectroscopy and gas chromatography-mass *** concentration,dehydrogenation enthalpy,and thermo-neutral temperature are calculated using a density functional *** results indicate that O-atom-containing material exhibits more favorable dehydrogenation thermodynamics than that of the hydrocarbon *** H2-rich material contains6.8 wt%of gravimetric hydrogen storage capacity.A preliminary study of catalytic dehydrogenation on a continuous reactor is presented to demonstrate a reversibility of this material.

关键词： Hydrogen storage Liquid organic hydrogen carrier Diphenyl ether Dehydrogenation Thermodynamics

Matrix Rings over Reflexive Rings

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Algebra Colloquium 2018年第3期25卷 459-474页

作者： Jeoung soo Cheon Tai Keun kwak Yang Lee Department of Mathematics Pusan National University Busan 46241 Korea Department of Mathematics Daejin University Pocheon 11159 Korea Institute of Basic Science Daejin University Pocheon 11159 Korea

The concept of reflexive property is introduced by Mason. This note concerns a ring-theoretic property of matrix rings over reflexive rings. We introduce the concept of weakly reflexive rings as a generalization of reflexive rings. From any ring, we can construct weakly reflexive rings but not reflexive, using its lower nilradical. We study various useful properties of such rings in relation with ideals in matrix rings, showing that this new property is Morita invariant. We also investigate the weakly reflexive property of several sorts of ring extensions which have roles in ring theory.

关键词： weakly reflexive ring reflexive ring power of ideal matrix ring ring of minimal order

Nano-precision combined process of electrolytic in-process dressing grinding and magnetic assisted polishing on optics glass material

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中国有色金属学会会刊：英文版 2009年第B09期19卷 301-306页

作者： Tae-soo kwak Yong-Chul LEE Gyung-Nyun KIM Dae-Bong CHOI Mikio YAMANOI Hitoshi OHMORI Department of Mechanical Engineering Jinju National University

This study is focused on the application of an effective fabrication method combining electrolytic in-process dressing(ELID) grinding and magnetic assisted polishing(MAP) to nano-precision mirror surface grinding on the optics glass-ceramic named Zerodure that is commonly used in precision optics components. The results show the variation of surface roughness after MAP processes utilizing Fe+CeO2, Fe+CeO2+diamond paste and Fe+diamond paste are applied to ELID ground surfaces. The MAP surface roughnesses for ELID ground surface roughnesses(Ra) of 52.1, 39.8 and 51.1 nm using #1200 grinding wheel are improved to 6.1, 4.6 and 1.9 nm, respectively. The surface roughness of MAP process using Fe+CeO2+diamond paste is superior to that using other processes. Moreover, it takes less than 10 min to conduct the MAP processes. The combined method suggested effectively reduces the working time to get the required surface qualities.

关键词：在线电解修整光学玻璃纳米相抛光材料电解过程表面粗糙度地面粗糙度磨削

Inhibitory effects of coronary vasodilator papaverine on heterologously-expressed HERG currents in Xenopus oocytes

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Acta Pharmacologica Sinica 2007年第4期28卷 503-510页

作者： Cuk-seong KIM Nam LEE sook-jin SON Kyu-seung LEE Hyo-shin KIM Yong-geun kwak soo-wan CHAE sang-do LEE Byeong-hwa JEON Jin-bong PARK Department of Physiology College of MedicineChungnam National UniversityDaejeon 301131Korea Department of Pharmacology Chonbuk National UniversityMedical SchoolChonju 561-180Korea

Aim:To characterize the effects of papaverine on HERG channels expressed inXenopus oocytes as well as cardiac action potential in rabbit ventricular ***:Conventional microelectrodes were used to record action potential inrabbit ventricular *** currents were recorded by 2-electrode voltageclamp technique in Xenopus oocytes injected with HERG ***:Papa-verine increased the cardiac action potential duration in rabbit ventricular *** blocked heterologously-expressed HERG currents in a concentration-depen-dent manner (IC5071.03±4.75 μmol/L,NH 0.80,n=6),whereas another phosphodi-esterase inhibitor,theophylline （500 μmol/L）,did *** blockade of papaverineon HERG currents was not *** slope conductance measuredas a slope of the fully activated HERG current-voltage curves decreased from78.03±4.25 μS of the control to 56.84±5.33,36.06±6.53,and 27.09±5.50 μS （n=4） by30,100,and 300 μmol/L of papaverine,*** （100 μmol/L）caused a 9 mV hyperpolarizing shift in the voltage-dependence of steady-stateinactivation,but there were no changes in the voltage-dependence of HERG cur-rent *** blocked HERG channels in the closed,open,andinactivated ***:These results showed that papaverine blockedHERG channels in a voltage-and state-independent manner,which may mostlikely be the major mechanism of papaverine-induced cardiac arrhythmia reportedin humans.

关键词： papaverine HERG cardiac action potential

Fabrication of High-Density Out-of-Plane Microneedle Arrays with Various Heights and Diverse Cross-Sectional Shapes

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Nano-Micro Letters 2022年第2期14卷 60-78页

作者： Hyeonhee Roh Young Jun Yoon Jin soo Park Dong-Hyun Kang Seung Min kwak Byung Chul Lee Maesoon Im Brain Science Institute Korea Institute of Science and Technology(KIST)Seoul 02792South Korea Division of Electrical Engineering College of EngineeringKorea UniversitySeoul 02841South Korea Micro/Nano Fabrication Center KISTSeoul 02792South Korea Division of Bio‑Medical Science&Technology KIST SchoolUniversity of Science&Technology(UST)Seoul 02792South Korea

Out-of-plane microneedle structures are widely used in various applications such as transcutaneous drug delivery and neural signal recording for brain machine *** work presents a novel but simple method to fabricate high-density silicon(Si)microneedle arrays with various heights and diverse cross-sectional shapes depending on photomask pattern *** proposed fabrication method is composed of a single photolithography and two subsequent deep reactive ion etching(DRIE)***,a photoresist layer was patterned on a Si substrate to define areas to be etched,which will eventually determine the final location and shape of each individual ***,the 1st DRIE step created deep trenches with a highly anisotropic etching of the Si ***,the photoresist was removed for more isotropic etching;the 2nd DRIE isolated and sharpened microneedles from the predefined trench *** on diverse photomask designs,the 2nd DRIE formed arrays of microneedles that have various height distributions,as well as diverse cross-sectional shapes across the *** these simple steps,high-aspect ratio microneedles were created in the high density of up to 625 microneedles mm^(-2)on a Si *** tests showed a small force as low as~172μN/microneedle is required for microneedle arrays to penetrate the dura mater of a mouse *** demonstrate a feasibility of drug delivery application,we also implemented silk microneedle arrays using molding *** fabrication method of the present study is expected to be broadly applicable to create microneedle structures for drug delivery,neuroprosthetic devices,and so on.

关键词： Microneedle Various heights Cross-sectional shapes Isotropic etch Deep reactive ion etching

Ipomoea batatas HKT1 transporter homolog mediates K^+ and Na^+ uptake in Saccharomyces cerevisiae

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Journal of Integrative Agriculture 2017年第10期16卷 2168-2176页

作者： PARK Sung-chul YU Yi-cheng KOU Meng YAN Hui TANG Wei WANG Xin LIU Ya-ju ZHANG Yun-gang kwak sang-soo MA Dai-fu SUN Jian LI Qiang Xuzhou Institute of Agricultural Sciences in Jiangsu Xuhuai District/Key Laboratory for Biology and Genetic Breeding of Sweet Potato Ministry of Agriculture/Sweet Potato Research InstituteChinese Academy of Agricultural Science Institute of Integrative Plant Biology School of Life ScienceJiangsu Normal University Plant Systems Engineering Research Center Korea Research Institute of Bioscience and Biotechnology

Soil salinity causes the negative effects on the growth and yield of crops. In this study, two sweet potato （Ipomoea batatas L.） cultivars, Xushu 28 （X-28） and Okinawa 100 （O-100）, were examined under 50 and 100 mmol L-1 NaCI stress. X-28 cultivar is relatively high salt tolerant than O-100 cultivar. Interestingly, real-time quantitative polymerase chain reaction （RT-qPCR） results indicated that sweet potato high-affinity K^＋ transporter 1 （IbHKT1） gene expression was highly induced by 50 and 100 mmol L-1 NaCI stress in the stems of X-28 cultivar than in those of O-100 cultivar, but only slightly induced by these stresses in the leaves and fibrous roots in both cultivars. To characterize the function of IbHKT1 transporter, we performed ion-flux analysis in tobacco transient system and yeast complementation. Tobacco transient assay showed that IbHKT1 could uptake sodium （Na^＋）. Yeast complementation assay showed that IbHKT1 could take up K^＋ in 50 mmol L^-1 K^＋ medium without the presence of NaCI. Moreover, Na^＋ uptake significantly increased in yeast overexpressing IbHKTI. These results showed that IbHKT1 transporter could have K^＋-Na^＋ symport function in yeast. Therefore, the modes of action of IbHKT1 in transgenic yeast could differ from the mode of action of the other HKT1 transporters in class I. Potentially, IbHKT1 could be used to improve the salt tolerance nature in sweet potato.

关键词： IbHKT1 Na^+/K^+transporter salt stress sweet potato

Critical cooling rate on carbide precipitation during quenching of austenitic manganese steel

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China Foundry 2010年第2期7卷 178-182页

作者： Youn-soo Ham Jeong-Tae Kim Si-Young kwak Jeong-Kil Choi Woo-Young Yoon Daeyang R-Tech.Co. Ltd290-28Daehwa-DongDaeduk-GuDaejeonKorea e-Design Center KITECH7-47Songdo-DongYeonsu-GuIncheon 406-800Korea Department of Materials Science and Engineering Korea UniversityAnam-DongSeongbuk-GuSeoul 136-701Korea

Critical cooling rate to avoid carbide precipitation during quenching of austenitic manganese steel was investigated by means of optical microscopy,image analyzer and numerical *** efficient heat treatment analysis program including temperature-dependent material properties was developed for the prediction of cooling rate and probability of carbide precipitation during quenching by finite difference ***-dependent heat transfer coefficient was adopted to achieve more precise *** ratio of carbide precipitation was measured by image analyzer to determine the critical point of carbide ***-dependent critical cooling rate at that point was calculated by the developed numerical ***,the probability of carbide precipitation on the whole area of specimen can be predicted by the proposed numerical program and the numerical result of a specimen was compared with the experimental result.

关键词： austenitic manganese steel carbide precipitation quenching critical cooling rate