检索结果-南通市图书馆

Autophagy in plants: Physiological roles and post-translational regulation

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2021年第1期63卷 161-179页

作者： Hua Qi Fan-Nv Xia shi xiao State Key Laboratory of Biocontrol Guangdong Provincial Key Laboratory of Plant ResourcesSchool of Life SciencesSun Yat-sen UniversityGuangzhou 510275China

In eukaryotes, autophagy helps maintain cellular homeostasis by degrading and recycling cytoplasmic materials via a tightly regulated *** the past few decades, significant progress has been made towards understanding the physiological functions and molecular regulation of autophagy in plant cells. Increasing evidence indicates that autophagy is essential for plant responses to several developmental and environmental cues, functioning in diverse processes such as senescence, male fertility, root meristem maintenance, responses to nutrient starvation,and biotic and abiotic stress. Recent studies have demonstrated that, similar to nonplant systems,the modulation of core proteins in the plant autophagy machinery by posttranslational modifications such as phosphorylation, ubiquitination,lipidation, S-sulfhydration, S-nitrosylation, and acetylation is widely involved in the initiation and progression of autophagy. Here, we provide an overview of the physiological roles and posttranslational regulation of autophagy in plants.

关键词： autophagy physiological roles post-translational regulation

HYDRAULIC CHARACTERISTICS OF VERTICAL VORTEX AT HYDRAULIC INTAKES

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2007年第2期19卷 143-149页

作者： CHEN Yun-liang WU Chao YE Mao ju xiao-ming State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China College of Hydraulic and Hydroelectric Engineering Sichuan University Chengdu 610065 China

The trace of vertical vortex flow at hydraulic intakes is of the shape of spiral lines, which was observed in the presented experiments with the tracer technique. It represents the fluid particles flow spirally from the water surface to the underwater and rotate around the vortex-axis multi-cycle. This process is similar to the movement of screw. To describe the multi-circle spiral characteristics under the axisymmetric condition, the vertical vortex would change not only in the radial direction but also in the axial direction. The improved formulae for three velocity components for the vertical vortex flow were deduced by using the method of separation of variables in this article. In the improved formulae, the velocity components are the functions of the radial and axial coordinates, so the multi-circle spiral flow of vertical vortex could be simulated. The calculated and measured results for the vertical vortex flow were compared and the causes of errors were analyzed.

关键词： vertical vortex tracer technique multi-circlespiral flow separation of variables

Speciation characterization and coagulation of poly-silica-ferric-chloride:The role of hydrolyzed Fe(Ⅲ) and silica interaction

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2011年第5期23卷 749-756页

作者： Jian shi Yan Zhang Kaiyun Zou Feng xiao Nantong University Nantong 226007 China. E-mail: shijianchuyu @ *** Key Laboratory of Environmental Water Chemistry Ecological Environment Research Center of Chinese Academy of Science Beijing 100085 China

The highly efficient inorganic polymer flocculants （IPFs） of the ferric-silica system is a new and promising coagulant. Interactions between ferric species and silica play a large part in the coagulation of suspensions. These effects are quite distinct from those associated with polymeric or colloid silica. However, although these species are key to coagulation efficiency, they have not been comprehensively discussed. A new type of coagulant, poly-silica-ferric-chloride （PFSC）, was synthesized by co-polymerization and characterized by time complexation spectroscopy and photon correlation spectroscopy. Compared with traditional ferric salt, the results indicated that PFSC had a higher molecular weight, lesser positive charge, lower Feb and higher Fec. The higher the Si/Fe ratio, the higher the silica and lower the silicac found. The PFSC with appropriate polysilica acid not only obtained better coagulation/flocculation efficiency in turbidity removal, enhanced the flocculation index （FI） and provided less residual ferric, it also lowered water treatment costs compared to traditional ferric salt. Results showed that PFSC could remove colloid particles in water by charge neutralization and sweeping, adsorption bridging mechanism.

关键词： coagulation inorganic polymer flocculant PFSC species distribution residual ferric

Mitigation of cross-eye jamming using a dual-polarization array

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2018年第3期29卷 491-498页

作者： MA Jiazhi shi Longfei xiao Shunping WANG Xuesong State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics and Information System National University of Defense Technology Changsha 410073China School of Science National University of Defense TechnologyChangsha 410073China

This paper presents an approach for mitigating the cross-eye jamming using a dual-polarization array. By transmitting a sum beam and a difference beam in two orthogonal polarimetric channels, a synthesized transmitted beam with spatially varying polarization is produced, such that the polarization of the transmitted radar wave varies in azimuth or elevation. Thus, the phases of the signals received on the two antennas of a cross-eye jammer become unequal, and an additional phase difference is introduced to disrupt the 180？ phase shifting in the retrodirective loop of the jammer. By means of beam scanning in a small angular range,the optimal beam steering configuration can be found to maximize the phase error for the mitigation of cross-eye jamming. As a result, the jamming performance of the cross-eye jammer degrades largely. Theoretical analysis and simulation results indicate that the proposed method is valid and feasible.

关键词： cross-eye jamming monopulse radar spatially varying polarization insertion phase beam scanning

Solidification structure refinement of ferritic stainless steel based on heterogeneous nucleation technology

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2019年第2期26卷 137-147页

作者： xiao-fang shi Li-zhong Chang Li Zhou School of Metallurgy Engineering Anhui University of TechnologyMa'anshan 243032AnhuiChina Key Laboratory of Metallurgical Emission Reduction and Resources Recycling(Anhui University of Technology) Ministry of EducationMa'anshan 243002AnhuiChina

The ridging defect on the surface of stainless steel products is related to the solidification structure of ferritic stainless *** the solidification structure and increasing the proport io n of equiaxed grains are necessary to lesse n the ridging ***,a new idea of using a heterogeneous nucieating agent which was composed of the composite core containing Ti was proposed,that is,a large amount of dispersed fine particles were initially formed on the solidification front,and a great amount ofδiron was then nucleated using these fine particles as the heterogeneous *** analyzing the crystallographic relationship between different crystals and inducing the calculation formulas of disregistry,the disregistry between the different oxides and TiNδiron was explored and the type of nucleation core was *** key parameters of forming the composite core containing Ti were obtained through a thermodynamic calculatio *** experimental results further con firm the correctness of the theoretical analysis.

关键词： Ferritic stainless steel Structure refinement Disregistry Heterogeneous nucleation Thermodynamics Solidification

Physical Characteristics of Welding Arc Ignition Process

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2012年第4期25卷 786-791页

作者： shi Linan SONG Yonglun xiao Tianjiao RAN Guowei College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology Beijing 100124 China

The existing research of welding arc mainly focuses on the stable combustion state and the research on the mechanism of welding arc ignition process is quite *** tungsten inert gas（TIG） touch arc ignition process is observed via a high speed camera and the high time resolution spectral diagnosis *** changing phenomenon of main ionized element provided the electrons in the arc ignition is *** metallic element is the main contributor to provide the electrons at the beginning of the discharging,and then the excitated shielding gas element replaces the function of the metallic *** electron density during the period of the arc ignition is calculated by the Stark-broadened lines of Hα.Through the discussion with the repeatability in relaxation phenomenon,the statistical regularity in the arc ignition process is *** similar rules as above are observed through the comparison with the laser-assisted arc ignition experiments and the metal inert gas（MIG） arc ignition *** research is helpful to further understanding on the generation mechanism of welding arc ignition and also has a certain academic and practical significance on enriching the welding physical theoretical foundation and improving the precise monitoring on automatic arc welding process.

关键词： welding arc ignition process physical characteristic spectral diagnosis

Perovskite thin-film solar cell: excitation in photovoltaic science

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2015年第2期58卷 221-238页

作者： junyan xiao Jiangjian shi Dongmei Li Qingbo Meng Key Laboratory for Renewable Energy Chinese Academy of Sciences Beijing Key Laboratory for New Energy Materials and Devices Institute of Physics Chinese Academy of Sciences

As a new member of thin-film solar cells, the perovskite solar ceils have inspired a new research hot in new photoelectric materials and devices, and have given a new energy to the photovoltaic science. Currently, various device structures, including mesoporous and planar, with and without hole transport material have been developed. In this review, much focus has been addressed to the deposition of high-quality perovskite films, structural optimization, and interface engineering as well as the understanding of the charge generation, transport, and recombination mechanisms of the devices. Furthermore, cost, stability, and environment issues of the cell are also discussed for commercial application.

关键词： perovskite solar cell photovoltaic device structure material interface

Effects of Rare Earth,Titanium,and Magnesium Additions on Microstructures and Properties of High-boron Medium-carbon Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2016年第11期23卷 1226-1233页

作者： xiao-li shi Ye-hua JIANG Rong ZHOU Faculty of Materials Science and Engineering Kunming University of Science and Technology

In order to improve the toughness and wear resistance of high-boron medium-carbon alloy （HBMCA）, a novel wear-resistant HBMCA comprising granular borocarbide was obtained by titanium, magnesium, and rare earth modifications. These modifications gave rise to greatly refined as-cast eutectic borocarbide structures and a less interconnected continuous borocarbide network. Heat treatment mostly produced broken and spheriodized borocarbides that tended to exist as isolated particles in modified HBMCA. The heat treated modified HBMCA exhibited enhanced hardness than pristine and impact toughness was improved significantly to 12.5 J/cm^2. In addition, it displayed 2.39 and 1.7 times greater wear resistance than high-speed steel （HSS） and high nickel-chromium alloy steel （Cr25） at high temperature （500℃）, respectively. Here, the modification mechanisms involving Re2O3, TiN, and MgO/ MgS heterogeneous nuclei were discussed.

关键词： modification eutectic borocarbide spheroidization toughness wear resistance

Hour-to-hour variability of the ionosphere: An application of the classical multidimensional scaling method

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2015年第7期58卷 1243-1250页

作者： shi Hao ZHANG DongHe HAO YongQiang xiao Zuo Department of Geophysics Peking University

The classical multidimensional scaling(MDS) method is introduced and applied in the study of the hour-to-hour ionospheric variability based on the ionospheric fo F2 observed at three ionosonde stations in East-Asia in 2002 and 2007. Results from the matrix eigen decompositions indicate that the annual part of the ionospheric variation is large in middle latitude and solar maximum period(2002) while low in the low latitude and solar minimum period(2007). The connectivity maps of the hour-to-hour ionospheric variability based on MDS method show some common diurnal features. The ionospheric connectivity between adjacent hours near noon hours and near midnight hours is high. The ionospheric connectivity between adjacent hours near sunrise hours and near sunset hours is poor, especially for the sunrise hours. Also there are latitudinal and solar activity dependences in this kind of connectivity. These results revealed from the ionospheric connectivity maps are useful physically and in practice for the ionospheric forecasting on the hour-to-hour scale.

关键词： ionospheric variability classical multidimensional scaling connectivity map