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2D DEM simulation of particle mixing in rotating drum: A parametric study

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Particuology 2010年第2期8卷 141-149页

作者： Yong xu chunhui xu Zhe Zhou Jing Du Daping Hu College of Sdence China Agricultural University Beijing 100083 China

Mixing behaviors of equal-sized glass beads in a rotating drum were investigated by both DEM simula- tions and experiments. The experiments indicated that higher rotation speed can significantly enhance mixing. The particle profiles predicted by 2D DEM simulation were compared with the experimental results from a quasi-2D drum, showing inconsistency due to reduction of contacts in the single-layer 2D simulation which makes the driving friction weaker than that in the quasi-2D test, better results could be reached by specifying a higher frictional coefficient between the particles and the cylinder wall. In order to explore the influences of physical properties （density, size or friction） on mixing behavior, numerical 2D simulations were carried out systematically, in which one examined specific property being examined was exaggerated while the others were kept the same as that in the control group. The DEM simulations reveal that particle density and size are the dominating factors affecting mixing behaviors, while the effect of frictional coefficient is less significant. However, segregation due to any of the factors can be diminished by specifying a proper particle size distribution （multi-size with lower size ratio）. 2009 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

关键词： Discrete Element Method Rotating drum Granule Mixing Mill Segregation

Molecular characterization of LMW-GS genes from a somatic hybrid introgression line Ⅱ-12 between Triticum aestivum and Agropyron elongatum in relation to quick evolution

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Journal of Genetics and Genomics 2008年第12期35卷 743-749页

作者： Fanguo Chen Feng Zhao chunhui xu Guangmin Xia School of Life Science Shandong University Jinan 250100 China

In order to exploit the evolution and find novel low-molecular-weight glutenin subunit （LMW-GS） for improvement of common wheat quality, thirteen variants from a somatic hybrid introgression line II-12 between Triticum aestivum cv. Jinan 177 （JN177） and Agropyron elongatum were characterized via genomic PCR. Four clones were pseudogenes because they contained an internal stop codon. The remaining nine variants contained intact open reading frames （ORFs）. Sequence alignment indicates that the proteins deduced from the nine ORFs have similar primary structure with LMW-GS cloned from its parents previously. However, they have some unique modifications in the structures. For example, EU292737 contains not only an extra Cys residue in the C-terminal domain but also a long repetitive domain. Both EU 159511 and EU292738 start their first Cys residue in the N-terminal repetitive domain, but not in the N-conserved domain traditionally. These structural alterations may have positive contributions to wheat flour quality. The results of phylogeny showed that most LMW-GS variances from 11-12 were homologous to those from parent JN177 and other wheat lines. The reason for quick evolution of LMW-GS in 11-12 was discussed.

关键词： Triticum aestivum somatic hybrid introgression line LMW-GS gene coding sequence evolution

Plane Analysis for an Inclusion in ID Hexagonal Quasicrys tai Using the Hyp er singular Integral Equation Method

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Acta Mechanica Solida Sinica 2019年第2期32卷 249-260页

作者： Fei Lou Ting Cao Taiyan Qin chunhui xu College of Science China Agricultural University Beijing 100083 China College of Engineering China Agricultural University Beijing 100083 China

A model of a thin elastic inclusion embedded in an infinite ID hexagonal quasicrystal is discussed. The atomic arrangements of the matrix and the inclusion are both periodic along the xi-direction and quasiperiodic along the a;2-direction in the oxiX2-coordinate system. Using the hypersingular integral equation method, the inclusion problem is reduced to solving a set of hypersingular integral equations. Based on the exact analytical solution of the singular phonon and phason stresses near the inclusion front, a numerical method of the hypersingular integral equation is proposed using the finite-part integral method. Finally, the numerical solutions for the phonon and phason stress intensity factors of some examples are given.

关键词： Elastic inclusion ID hexagonal quasicrystal Hypersingular integral equations

A New Method of Portfolio Optimization Under Cumulative Prospect Theory

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Tsinghua Science and Technology 2018年第1期23卷 75-86页

作者： Chao Gong chunhui xu Masakazu Ando Xiangming Xi Department of Risk Science in Finance and Management Chiba Institute of Technology Chiba 275-0016 Japan Department of Automation Tsinghua University Beijing 100084 China

In this paper, the portfolio selection problem under Cumulative Prospect Theory （CPT） is investigated and a model of portfolio optimization is presented. This model is solved by coupling scenario generation techniques with a genetic algorithm. Moreover, an Adaptive Real-Coded Genetic Algorithm （ARCGA） is developed to find the optimal solution for the proposed model. Computational results show that the proposed method solves the portfolio selection model and that ARCGA is an effective and stable algorithm. We compare the portfolio choices of CPT investors based on various bootstrap techniques for scenario generation and empirically examine the effect of reference points on investment behavior.

关键词： portfolio choice cumulative prospect theory bootstrap method adaptive real-coded genetic algorithm

The squeeze flow of a bi-viscosity fluid between two rigid spheres with wall slip

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Particuology 2023年第8期79卷 153-160页

作者： Tianyi Zhou Da Lin Yujia Shen Wei Yang chunhui xu xuedong Chen College of Science China Agricultural UniversityBeijing100083China Chinese Academy of Agricultural Mechanization Sciences Group Co. LtdBeijing100083China

In this paper,the squeeze flow between two rigid spheres with a bi-viscosity fluid is *** on lubrication theory,the squeeze force is calculated by deriving the pressure and velocity *** results of the normal squeeze force are discussed,and fitting functions of the squeeze and correction coefficients are *** squeeze force between the rigid spheres increases linearly or logarithmically with the velocity when most or part of the boundary fluid reaches the yield state,***,the slip correction coefficient decreases with the increase in the *** investigation may contribute to the further study of bi-viscosity fluids between rigid spheres with wall slip.

关键词： Squeeze flow Bi-viscosity fluid Rigid spheres Wall slip

An unbalanced PD-L1/CD86 ratio in CD14^＋＋CD16^＋ monocytes is correlated with HCV viremia during chronic HCV infection

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Cellular & Molecular Immunology 2014年第3期11卷 294-304页

作者： Jiajia Zheng Hua Liang chunhui xu Qiang xu Ting Zhang Tao Shen Fengmin LU Department of Microbiology Peking University Health Science Center Beijing China Department of Laboratory Medicine Peking University Third Hospital Beijing China State Key Laboratory for infectious Disease Prevention and Control National Center for AIDS/STD Control and Prevention China CDC Beijing China Center of Infectious Diseases Peking University Beijing China These authors contributed equally to this work

Circulating monocyte subsets with distinct functions play important roles in hepatitis C virus （HCV） infection. However, the mechanisms have not been well studied. In this study, we analyzed the distributions and phenotypic characteristics of three circulating monocyte subsets--CD14^＋＋CD16^-, CD14^＋＋CD16^＋ and CD14^＋＋mCD16^——in chronic HCV-infected patients, HCV spontaneous resolvers and healthy controls, and we evaluated the possible link between HCV viremia and disease progression. Our results indicated that the frequency of the CD 14^＋＋CD 16^＋ monocyte subset was decreased, and negatively correlated with HCV RNA and core antigen levels during chronic HCV infection. PD-L1 expression and the PD-L1/CD86 ratio in CD14^＋＋CD16^＋ monocytes were higher during chronic HCV infection than in spontaneous HCV resolvers and healthy controls. The PD-L1/CD86 ratio positively correlated with HCV viral load and core antigen levels. Finally, PD-L1 was significantly increased, while cytokine secretions were dramatically decreased upon Toll-like receptor （TLR） ligand binding and HCV JFH-lstimulation. These findings indicates the compromised immune status of the CD14^＋＋CD16^＋ monocytes during chronic HCV infection and provides new insights into the specific role of the CD14^＋＋CD16^＋ monocytes and their significance in chronic HCV infection.

关键词： core antigen hepatitis C virus monocytes PD-L1/CD86 viral load

Non-seismic geophysical analysis of potential geothermal resources in the Longgang Block,Northeast China

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Earth and Planetary Physics 2022年第6期6卷 576-591页

作者： HaiYan Liu Chong Peng LinFu xue WenQing Li chunhui xu Cremilda Samuel Jofrisse College of Earth Sciences Jilin UniversityChangchun 130061China College of Geographical Sciences Shanxi Normal UniversityTaiyuan 030031China Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China College of Geo-exploration Science and Technology Jilin UniversityChangchun 130026China School of GeoSciences University of EdinburghEdinburgh EH93JWUK College of Tourism and Geographical Sciences Jilin Normal UniversitySiping Jilin 136000China

Although geothermal energy has many clear advantages,including its sustainability and environmentally friendly nature,research into potential geothermal resources across the Longgang Block,Northeast China,has been *** we present the first analysis of the potential geothermal resources in this region that employs joint geological and non-seismic geophysical methods to identify target areas that may be economically *** acquire and analyze high-precision gravity,magnetic,and magnetotelluric sounding data,which are constrained using the petrophysical parameters of outcropping rocks across the Longgang Block,to conduct a comprehensive evaluation of the region’s deep geological structures and their geothermal resources potential,with a focus on identifying faults,rock masses,and thermal storage *** find that Archean granitic gneiss and Mesozoic rock masses in the deeper section of the Longgang Block possess weak gravity anomalies and high *** also identify thermal storage structures near these deeper geological units based on their extremely low *** data are used to infer the dip and depth of known or hidden faults,to constrain the spatial distribution of intrusive rock masses,and to determine the spatial distribution of subsurface thermal storage *** potential of the target areas for geothermal resources exploitation is divided into three grades based on contact depths between faults and thermal storage structures,and the scale of their thermal storage *** results suggest that a joint non-seismic geophysical approach can be effective in locating and evaluating geothermal resources in complex geological settings.

关键词： Longgang Block geothermal resources Anshan−Benxi area petrophysical parameters magnetotelluric sounding

Hexyl substitution of pentathienoacene toward a significant improvement in charge transport

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Chinese Chemical Letters 2019年第4期30卷 903-905页

作者： Ping He Hantang Zhang chunhui xu Yonggang Zhen Huanli Dong Wenping Hu Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province China West Normal University Beijing National Laboratory for Molecular Science Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences College of Chemistry and Material Science Shandong Agriculture University Tianjin Key Laboratory of Molecular Optoelectronic Sciences Department of Chemistry School of Science Tianjin University and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)

A novel semiconductor, dihexyl-substituted pentathienoacene(C6-PTA) is designed and synthesized in five steps with the total yield up to 25.2%. The introduction of hexyl chains endow the thin film semiconductor with about threefold increase in carrier mobility and one to three orders of magnitude improvement in current on/off ratio. Furthermore, single crystal FETs based on C6-PTA exhibited mobility up to 0.64 cm^2 V^(-1) s^(-1), which is over 50 times higher than the thin film counterpart. The results indicate clearly that C6-PTA is a promising organic semiconductor with high stability.

关键词： Organic field-effect transistors Organic semiconductors Thienoacene Charge transport Stability

The DEAD-box RNA helicase ZmRH48 is required for the splicing of multiple mitochondrial introns,mitochondrial complex biosynthesis,and seed development in maize

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Journal of Integrative Plant Biology 2023年第11期65卷 2456-2468页

作者： Yan-Zhuo Yang Shuo Ding Xin-Yuan Liu chunhui xu Feng Sun Bao-Cai Tan Key Laboratory of Plant Development and Environmental Adaptation Biology Ministry of EducationSchool of Life SciencesShandong UniversityQingdao 266237China

RNA helicases participate in nearly all aspects of RNA metabolism by rearranging RNAs or RNA–protein complexes in an adenosine triphosphatedependent *** to the large RNA helicase families in plants,the precise roles of many RNA helicases in plant physiology and development remain to be ***,we show that mutations in maize(Zea mays)DEAD-box RNA helicase48(Zm RH48)impair the splicing of mitochondrial introns,mitochondrial complex biosynthesis,and seed *** of Zm RH48 function severely arrested embryogenesis and endosperm development,leading to defective kernel *** RH48 is targeted to mitochondria,where its deficiency dramatically reduced the splicing efficiency of five cis-introns(nad5 intron 1;nad7 introns 1,2,and 3;and ccm Fc intron 1)and one trans-intron(nad2 intron 2),leading to lower levels of mitochondrial complexes I andⅢ.Zm RH48 interacts with two unique pentatricopeptide repeat(PPR)proteins,PPR-SMR1 and SPR2,which are required for the splicing of over half of all mitochondrial ***-SMR1 interacts with SPR2,and both proteins interact with P-type PPR proteins and Zm-m CSF1 to facilitate intron *** results suggest that Zm RH48 is likely a component of a splicing complex and is critical for mitochondrial complex biosynthesis and seed development.

关键词： intron splicing maize mitochondria RNA helicase seed development ZmRH48