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A Quantitative Study on the Effect of Heat Treatment on the Microstructure and Orientation of Titanium Hydride in Electrochemically Hydrogenated Pure Titanium

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Acta Metallurgica Sinica(English Letters) 2022年第12期35卷 2057-2068页

作者： Changzheng Li Yunchang Xin Guangjie Huang qing liu International Joint Laboratory for Light Alloys College of Materials Science and EngineeringChongqing UniversityChongqing 400030China Key Laboratory for Light-Weight Materials Nanjing Tech UniversityNanjing 210009China

The electrochemical hydrogen charging of pure titanium and its alloys has been investigated previously,while how a subsequent annealing treatment aff ects the type of hydride and its orientation relationship with matrix is not *** the present study,a quantitative study on the microstructure and orientation of titanium hydrides during electrochemical hydrogen charging and subsequent annealing treatment was carried out using scanning electron microscopy,transmission electron microscopy and electron backscatter diff *** results show thatδ-hydride is the main in both the electrochemically hydrogenated sample and the subsequent annealing treated *** electrochemical hydrogen charging for 48 h,the surface is mainly composed of denseδ-hydride with a thickness of approximately 42μm,the orientation relationship betweenα-matrix andδ-hydride follows only the orientation relationship of OR2,{0001}_(α)//{111}_(δ),_(α)//_(δ) and an interface plane{1013}_(a)//{110}_(δ).Besides OR2,a part of hydrides show an orientation relationship of OR1 with the matrix after annealing,{0001}a//{001}_(δ),_(a)//{110}_(δ) and an interface plane of {1010}_(δ)//{110}_(δ).It is further found that the relative frequency of OR1and OR2 is closely related to annealing *** an argon atmosphere at 450℃,the frequencies of OR1 and OR2 are nearly balance with an annealing time of 12 h,while OR1 becomes to be the predominant one with a relative frequency of 96.5%after annealing for 96 *** mechanism for the evolution of orientation relationship of hydrides with annealing time was discussed.

关键词： Titanium alloys Titanium hydride Heat treatment Microstructure Orientation relationship

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Progress and Future Development of Lancang-Mekong Cooperation

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国际问题研究 2018年第3期 199-215页

作者： liu qing Department for Asia-Pacific Security and Cooperation China Institute of International Studies (CIIS)

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Spatiotemporal evolution and driving forces of changes in rural settlements in the poverty belt around Beijing and Tianjin： a case study of Zhangjiakou city, Hebei Province

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Journal of Mountain Science 2017年第5期14卷 980-997页

作者： SUN Pi-ling XU Yue-qing liu qing-guo liu Chao WANG Hong-liang College of Resource and Environmental Sciences China Agricultural University Belling 100193 China Qianjiang Xinhua Middle School Chongqing 409000 China

The rural settlement is one of important aspects to understand regional human-environment relationships. Zhangjiakou city, located in the poverty belt around Beijing and Tianjin, was used as an example to analyze the evolution of rural settlements during 1985–2010 through the use of statistical and spatial analysis methods. The results demonstrate the following:(1) the area of rural settlements expanded from 665.76 to 928.14 km2 during 1985–2010. Rural settlements in prefecture city of Zhangjiakou were significantly agglomerated in terms of their spatial distribution, which presented an approximately normal distribution over the entire period. Rural settlements were usually distributed within regions where the terrain niche had an elevation of between 900 and 1500 m, and a slope from 5? to 20?;(2) there were significant regional differences in the density and size distribution of rural settlements in Zhangjiakou. The density of rural settlements in 2010 was higher than that in 1985, while there was a clustered distribution of rural settlements in 2010. There was a significant high value cluster in the size distribution, and a local negative correlation between the size and density distribution of rural settlements in Zhangjiakou;(3) rural economic development, investment in agricultural technology, and infrastructure improvement played important roles in the evolution of rural settlements. There were spatial differences in the relationship between the distribution of rural settlements and socio-economic factors in Zhangjiakou. This study provides practical guidance for the achievement of urban and rural integration development and the promotion of a new form of countryside construction.

关键词： Rural settlement Spatiotemporal evolution Driving factors Geographical weighted regression Zhangjiakou city

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Inhomogeneous deformation of {111} grain in cold rolled tantalum

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Journal of Materials Science & Technology 2018年第11期34卷 2178-2182页

作者： Yahui liu Shifeng liu Chao Deng Haiyang Fan Xiaoli Yuan qing liu College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Electron Microscopy Center of Chongqing University Chongqing UniversityChongqing 400044China Department of Mechanical Engineering KU LeuvenLeuvenBelgium School of Metallurgy and Material Engineering Chongqing University of Science and TechnologyChongqing 401331China

The microstructures of {111} grain were characterized in detailed and systematically investigated with the aid of electron backscatter diffraction(EBSD) and transmission electron microscope(TEM). The stored energy in different regions in the grain was evaluated by the band contrast values collected from EBSD. The results show that the distribution of energy is inhomogeneous through the grain. Especially,the regions containing the least and the largest energy were extracted from the EBSD data, and then quantitatively analyzed based on the misorientation and Schmid factor. Many peaks with large misorientation appeared in the region containing larger energy, and these peaks represent the existences of micro-bands and micro-shear bands in {111} grain. The results of Schmid factor suggest that the region containing larger energy is prone to deforming ahead of the region with less stored energy, implying the more serious subdivision of the microstructure of region with larger stored energy.

关键词： Tantalum Stored energy Misorientation Schmid factor

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Sake or supper? Breeding rice for culinary excellence and optimal brewing

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Molecular Plant 2023年第12期16卷 1879-1881页

作者： Changquan Zhang qing liu Qiaoquan liu Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding Zhongshan Biological Breeding LaboratoryCollege of AgricultureYangzhou UniversityYangzhou225009China

Improving grain quality is a paramount objective within modern rice breeding *** concept of rice grain quality is intricate,comprising aspects related to milling,appearance,cooking,nutrition,and hygiene(Custodio et al.,2019).It is well established that the quality of rice grain is a sophisticated quantitative trait governed by multiple genes(Ren et al.,2023).Over the past decade,tremendous efforts have been made to breed elite rice varieties with desired grain quality *** instance,the culinary quality of contemporary indica rice has undergone significant enhancements through the substitution of the Wxb allele in place of the Wxa allele,a pivotal domestication-related gene controlling rice grain amylose content,affecting both its cooking and consumption qualities(Zhang et al.,2019;Gu et al.,2023).Recent genomic studies on various modern cultivars and landraces have pinpointed multiple domesticated genes,as well as specific genomic regions,that contribute to distinct agronomic traits and environmental adaptations(liu et al.,2023).Nevertheless,the identification of genes related to grain quality that have been selected through breeding in modern cultivars continues to be constrained because of the complex regulatory networks implicated.

关键词： breeding cultivar elite

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Fixed-point ICA algorithm for blind separation of complex mixtures containing both circular and noncircular sources

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The Journal of China Universities of Posts and Telecommunications 2016年第2期23卷 15-23页

作者： Yao Junliang Ren Haipeng liu qing School of Automation and Information Engineering Xi'an University of Technology

Fixed-point algorithms are widely used for independent component analysis（ICA） owing to its good convergence. However, most existing complex fixed-point ICA algorithms are limited to the case of circular sources and result in phase ambiguity, that restrict the practical applications of ICA. To solve these problems, this paper proposes a two-stage fixed-point ICA（TS-FPICA） algorithm which considers complex signal model. In this algorithm, the complex signal model is converted into a new real signal model by utilizing the circular coefficients contained in the pseudo-covariance matrix. The algorithm is thus valid to noncircular sources. Moreover, the ICA problem under the new model is formulated as a constrained optimization problem, and the real fixed-point iteration is employed to solve it. In this way, the phase ambiguity resulted by the complex ICA is avoided. The computational complexity and convergence property of TS-FPICA are both analyzed theoretically. Simulation results show that the proposed algorithm has better separation performance and without phase ambiguity in separated signals compared with other algorithms. TS-FPICA convergences nearly fast as the other fixed-point algorithms, but far faster than the joint diagonalization method, e.g. joint approximate diagonalization of eigenmatrices（JADE）.

关键词： ICA fixed-point iteration noncircular complex signal phase ambiguity

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Cloning, expression and biocharacterization of OfCht5, the chitinase from the insect Ostrinia furnacalis

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Insect Science 2013年第2期20卷 147-157页

作者： qingyue Wu Tian liu qing Yang Department of Bioscience and Biotechnology Dalian University of Technology Dafian China

Chitinase catalyzes β,4-glycosidic linkages in chitin and has attracted re- search interest due to it being a potential pesticide target and an enzymatic tool for preparation of N-acetyl-β D-glucosamine. An individual insect contains multiple genes encoding chitinases, which vary in domain architectures, expression patterns, physiological roles and biochemical properties. Herein, Of ChtS, the glycoside hydrolase family 18 chiti- nase from the widespread lepidopteran pest Ostrinia furnacalis, was cloned, expressed in the yeast Pichia pastoris and biochemically characterized in an attempt to facilitate both pest control and biomaterial preparation. Complementary DNA sequence analysis indicated that Of CHT5 consisted of an open reading frame of 1 665-bp nucleotides. Phy- logenic analysis suggested Of Cht5 belongs to the Group I insect chitinases. Expression of Of Cht5 in Pichia pastoris resulted in highest specific activity after 120 h of induction with methanol. Through two steps of purification, consisting of ammonium sulfate pre- cipitation and metal chelating chromatography, about 7 mg of the recombinant Of Cht5 was purified to homogeneity from 1 L culture supernatant. Of Cht5 effectively converted colloidal chitin into chitobiose, but had relatively low activity toward a-chitin. When chi- tooligosaccharides [（GlcNAc）n, n = 3-6] were used as substrates, Of Cht5 was observed to possess the highest catalytic efficiency parameter toward （GlcNAc）4 and predominan- tely hydrolyzed the second glycosidic bond from the non-reducing end. Together with fl-N-acetyl-D-hexosaminidase OfHexl, Of Cht5 achieved its highest efficiency in chitin degradation that yielded N-acetyl-β D-glucosamine, a valuable pharmacological reagent and food supplement, within a molar concentration ratio of Of Cht5 versus Of Hexl in the range of 9 ： 1-15 ： 1. This work provides an alternative to existing preparation of chitinase for pesticides and other applications.

关键词： chitin chitinase glycoside hydrolase N-acetyl-β-D-glucosamine Ostriniafurnacalis pest control

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Existence and Uniqueness of Solutions for two Classes of Functional Equations Arising in Dynamic Programming

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Acta Mathematicae Applicatae Sinica 2007年第2期23卷 195-208页

作者： Ze-qing liu Shin Min Kang Department of Mathematics Liaoning Normal University P.O. Box 200 Dalian 116029 China Department of Mathematics and The Research Institute of Natural Science Gyeongsang National UniversityChinju 660-701 Korea

In this paper we establish the existence, uniqueness and iterative approximation of solutions for two classes of functional equations arising in dynamic programming of multistage decision processes. The results presented here extend, and unify the corresponding results due to Bellman, Bhakta and Choudhury, Bhakta and Mitra, liu and others.

关键词： Functional equation dynamic programming fixed point successive approximation nonexpansive mapping

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THE POSITIVE SOLUTION OF CLASSICAL GELFAND MODEL WITH COEFFICIENT THAT CHANGE SIGN

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Applied Mathematics and Mechanics(English Edition) 2002年第12期23卷 1458-1463页

作者： YAO qing-liu(姚庆六) Department of Applied Mathematics Nanjing University of EconomicsNanjing 210003 P R China

The existence and iteration of positive solution for classical Gelfand models are considered, where the coefficient of nonlinear term is allowed to change sign in [0, 1]. By using the monotone iterative technique, an existence theorem of positive solution is obtained, corresponding iterative process and convergence rate are given. This iterative process starts off with zero function, hence the process is simple, feasible and effective.

关键词： Gelfand model coefficient changed sign positive solution existence monotone iterative technique

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THE NATURAL CONVECTION OF AQUIFERS WITH CONSTANT HEAT SOURCES AND ITS INFLUENCE ON TEMPERATURE FIELDS

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Journal of Hydrodynamics 2012年第4期24卷 617-627页

作者： liu Guo-qing ZHOU Zhi-fang School of Earth Science and Engineering Hohai UniversityNanjing 210098China

By combining sand tank tests with numerical simulations, this paper studies the temperature fields around constant heat sources to reveal the mechanism of the natural convection and its influence on the temperature fields in the process of energy storage. Using the ＂24-channel temperature auto acquisition system＂ developed by our research group in the tests, the temperatures are recorded at measuring points within the research area in the tests, the revised Brinkman equation and a transfer-convection balance model are used for solving the aquifer water-thermal coupling problems, and through comparison of the test results with the calcula- tion results, it is discovered that the influence ranges and the variations of the two temperature fields are consistent, which validates the mathematical model. On the basis of this, we also study the influences of the heat source positions and the boundary conditions on the temperature fields, and the results show that, under the natural convection, the heat source positions may influence the distri- bution of the temperature fields, thus affect the energy storage. For the same energy storage layer, the temperature field for the top energy storage is characterized by a smaller heat influence range and a relatively concentrated temperature distribution. However, when the heat source is at the bottom, the range of a temperature field, and the temperature is relatively dispersed, which is not favorable to heat recycle, with the same heat source position, the boundary conditions determine the size of the critical Rayleigh number, and thus have an influence on the occurrence and the strength of the natural convection, and accordingly, on the temperature fields.

关键词： porous media natural convection water-thermal coupling sand tank test numerical simulation

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