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The convergence rate and necessary-and-sufficient condition for the consistency of isogeometric collocation method

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Applied Mathematics(A Journal of Chinese Universities) 2022年第2期37卷 272-289页

作者： LIN Hong-wei XIONG yun-yang HU Hui YAN Jia-cong HU Qian-qian School of Mathematical Science Zhejiang UniversityHangzhou 310027China Department of Mathematics Zhejiang Gongshang UniversityHangzhou 310018China

Although the isogeometric collocation(IGA-C)method has been successfully utilized in practical applications due to its simplicity and efficiency,only a little theoretical results have been established on the numerical analysis of the IGA-C *** this paper,we deduce the convergence rate of the consistency of the IGA-C ***,based on the formula of the convergence rate,the necessary and sufficient condition for the consistency of the IGA-C method is *** results advance the numerical analysis of the IGA-C method.

关键词： isogeometric collocation consistency necessary and sufficient condition convergence rate

Efficient modeling of cable-pulley system with friction based on arbitrary-Lagrangian-Eulerian approach

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Applied Mathematics and Mechanics(English Edition) 2017年第12期38卷 1785-1802页

作者： yun PENG Yadong wei Ming ZHOU Science and Technology Innovation Institute Dongguan University of Technology Dongguan 523808Guangdong ProvinceChina School of Aerospace Engineering Tsinghua UniversityBeijing 100084China

In conventional modeling of a cable-pulley system, the cable must be finely meshed with Lagrangian elements for valid contact detections with pulleys, leading to extremely low efficiency. The sliding joint method based on the arbitrary-Lagrangian- Eulerian （ALE） formulation still lacks an efficient cable element, and in particular, modeling of friction between a sliding joint and the cable has not been studied. This paper presents efficient multi-body modeling of a cable-pulley system with friction. A variable- length cable element with a node movable along the cable, which is described with ALE, is developed to mesh the cable. A transitional cable element is then proposed to model the contact part of the cable by fixing its two nodes to the two corresponding locations of the pulley. Friction of the cable-pulley is derived as a simple law of tension decay and embedded in the multi-body system modeling. It is simplified as a generalized friction force acting only on the arc-length coordinate. This approach can use a rough mesh on the cable, and is free of contact detections, thus significantly saving computation time. Several examples are presented to validate the proposed method, and show its effectiveness in real engineering applications.

关键词： cable-pulley system length-variable friction arbitrary-Lagrangian-Eulerian(ALE) cable tension decay dynamics

Energy consumption and emission mitigation prediction based on data center traffic and PUE for global data centers

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Global Energy Interconnection 2020年第3期3卷 272-282页

作者： Yanan Liu Xiaoxia wei Jinyu Xiao Zhijie Liu yang Xu yun Tian School of Artificial Intelligence Beijing Normal UniversityHaidian DistrictBeijng 100875China Global Energy Interconnection Development and Cooperation Organization Xicheng DistrictBeijing 100031China

With the rapid development of technologies such as big data and cloud computing,data communication and data computing in the form of exponential growth have led to a large amount of energy consumption in data ***,data centers will become the world’s largest users of energy consumption,with the ratio rising from 3%in 2017 to 4.5%in *** to its unique climate and energy-saving advantages,the high-latitude area in the Pan-Arctic region has gradually become a hotspot for data center site selection in recent *** order to predict and analyze the future energy consumption and carbon emissions of global data centers,this paper presents a new method based on global data center traffic and power usage effectiveness(PUE)for energy consumption ***,global data center traffic growth is predicted based on the Cisco’s ***,the dynamic global average PUE and the high latitude PUE based on Romonet simulation model are obtained,and then global data center energy consumption with two different scenarios,the decentralized scenario and the centralized scenario,is analyzed quantitatively via the polynomial fitting *** simulation results show that,in 2030,the global data center energy consumption and carbon emissions are reduced by about 301 billion kWh and 720 million tons CO2 in the centralized scenario compared with that of the decentralized scenario,which confirms that the establishment of data centers in the Pan-Arctic region in the future can effectively relief the climate change and energy *** study provides support for global energy consumption prediction,and guidance for the layout of future global data centers from the perspective of energy ***,it provides support of the feasibility of the integration of energy and information networks under the Global Energy Interconnection conception.

关键词： Data center Pan-Arctic Energy consumption carbon emission Data traffic PUE Global Energy Interconnection

Design of a Two-Step Calibration Method of Kinematic Parameters for Serial Robots

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Chinese Journal of Mechanical Engineering 2017年第2期30卷 438-448页

作者： wei WANG Lei WANG Chao yun School of Mechanical Engineering and Automation Beihang University State Key Lab of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology

Serial robots are used to handle workpieces with large dimensions, and calibrating kinematic parameters is one of the most efficient ways to upgrade their accuracy. Many models are set up to investigate how many kinematic parameters can be identified to meet the minimal principle, but the base frame and the kinematic parameter are indistinctly calibrated in a one-step way. A two-step method of calibrating kinematic parameters is proposed to improve the accuracy of the robot＇s base frame and kinematic parameters. The forward kinematics described with respect to the measuring coordinate frame are established based on the product- of-exponential （POE） formula. In the first step the robot＇s base coordinate frame is calibrated by the unit quaternion form. The errors of both the robot＇s reference configuration and the base coordinate frame＇s pose are equivalently transformed to the zero-position errors of the robot＇s joints. The simplified model of the robot＇s positioning error is established in second-power explicit expressions. Then the identification model is finished by the least square method, requiring measuring position coordinates only. The complete subtasks of calibrating the robot＇ s 39 kinematic parameters are finished in the second step. It＇s proved by a group of calibration experiments that by the proposed two-step calibration method the average absolute accuracy of industrial robots is updated to 0.23 mm. This paper presents that the robot＇s base frame should be calibrated before its kinematic parameters in order to upgrade its absolute positioning accuracy.

关键词： Kinematic parameter Calibration Error model Product of exponential Industrial robot

tP40 carbon: A novel superhard carbon allotrope

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Chinese Physics B 2020年第10期29卷 392-400页

作者： Heng Liu Qing-yang Fan Fang yang Xin-Hai Yu wei Zhang Si-Ning yun College of Information and Control Engineering Xi'an University of Architecture and TechnologyXi'an 710055China Department of Mechanical and Electrical Engineering Hetao CollegeBayannur Inner Mongolia 015000China School of Microelectronics Xidian UniversityXi'an 710071China Functional Materials Laboratory School of Materials Science and EngineeringXi'an University of Architecture and TechnologyXi'an 710055China

In this work, a novel carbon allotrope tP40 carbon with space group P4/mmm is proposed. The structural stability, mechanical properties, elastic anisotropy, and electronic properties of tP40 carbon are investigated systematically by using density functional theory (DFT). The calculated elastic constants and phonon dispersion spectra indicate that the tP40 phase is a metastable carbon phase with mechanical stability and dynamic stability. The B/G ratio indicates that tP40 carbon is brittle from 0 GPa to 60 GPa, while tP40 carbon is ductile from 70 GPa to 100 GPa. Additionally, the anisotropic factors and the directional dependence of the Poisson's ratio, shear modulus, and Young's modulus of tP40 carbon at different pressures are estimated and plotted, suggesting that the tP40 carbon is elastically anisotropic. The calculated hardness values of tP40 carbon are 44.0 GPa and 40.2 GPa obtained by using Lyakhov–Oganov's model and Chen's model, respectively, which means that the tP40 carbon can be considered as a superhard material. The electronic band gap within Heyd–Scuseria–Ernzerhof hybrid functional (HSE06) is 4.130 eV, and it is found that the tP40 carbon is an indirect and wider band gap semiconductor material.

关键词： novel carbon allotrope elastic properties anisotropy superhard material

Facile synthesis of C_(3)N_(4)-supported metal catalysts for efficient CO_(2) photoreduction

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Nano Research 2022年第1期15卷 551-556页

作者： yun-Nan Gong Bi-Zhu Shao Jian-Hua Mei wei yang Di-Chang Zhong Tong-Bu Lu Institute for New Energy Materials and Low Carbon Technologies School of Materials Science and EngineeringSchool of Chemistry and Chemical EngineeringTianjin University of TechnologyTianjin 300384China Key Laboratory of Jiangxi University for Functional Material Chemistry College of Chemistry&Chemical EngineeringGannan Normal UniversityGanzhou 341000China

Facile synthesis of photocatalysts with highly dispersed metal centers is a high-priority target yet still a significant *** this work,a series of Co-C_(3)N_(4) photocatalysts with different Co contents atomically dispersed on g-CaN4 have been prepared via one-step thermal treatment of cobalt-based metal-organic frameworks(MOFs)and urea in the *** to the highly dispersed and rich exposed Co sites,as well as good charge separation efficiency and abundant mesopores,the optimal 25-Co-C_(3)N_(4),in the absence of noble metal catalysts/sensitizers,exhibits excellent performance for photocatalytic C0_(2) reduction to CO under *** irradiation,with a high CO evolution rate of 394.4μmol·g^(-1)·h^(-1),over 80 times higher than that of pure g-C_(3)N_(4)(4.9μmol·g^(-1)·h^(-1)).In:addition,by this facile synthesis strategy,the atomically dispersed Fe and Mn anchoring on g-C_(3)N_(4)(Fe-C_(3)N_(4) and Mn-C_(3)N_(4))have been also obtained,indicating the reliability and universality of this strategy in synthesizing photocatalysts with highly dispersed metal *** work paves a new way to develop cost-effective photocatalysts for photocatalytic C0_(2) reduction.

关键词： metal-organic frameworks highly dispersed metal g-C_(3)N_(4) photocatalysts C02 reduction

Size control of SBA-15 by tuning the stirring speed for the formation of CMK-3 with distinct adsorption performance

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Nano Research 2016年第8期9卷 2294-2302页

作者： Qi Wang Zhencai Wang Tianhao Zheng Xiongping Zhou wei Chen Dekun Ma yun yang Shaoming Huang Key Laboratory of Carbon Materials of Zhejiang Province College of Chemistry and Materials Engineering Wenzhou UniversityWenzhou 325027 China

Controlling the size of SBA-15 can be beneficial for exploiting CMK-3, which has excellent structural parameters, for better performance in adsorption and/or catalytic processes. In this study, the width of freestanding SBA-15 rods was readily and successfully regulated by simply altering the stirring power during the synthesis. A higher stirring rate produced SBA-15 rods with larger width. Then, the size of the CMK-3 rods was adjusted by duplication of the different- sized SBA-15. The results show that the larger sized CMK-3 has higher specific surface area and pore volume, which led to a higher adsorption capacity and a faster adsorption rate. It is believed that the synthetic method reported here is powerful for developing better mesoporous carbon for application in water purification and catalysis.

关键词： SBA-15 CMK-3 size control adsorption

Synthesis, Crystal Structure and Spectral Property of a Water-bridged Co(Ⅱ) Coordination Polymer with 3-Flavonoxylacetic Acid Ligand

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Chinese Journal of Structural Chemistry 2019年第3期38卷 369-375页

作者： KONG yang-yang FAN Hui wei Xiao-Yi CAI Shuang-Lian CHEN yun State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical Engineering Hunan University

A new cobalt complex with flavonoid carboxylate ligand was synthesized and characterized. X-ray diffraction data revealed that the compound crystallizes in the monoclinic crystal system, space group P2_1/c with a = 7.936(3), b = 21.475(7), c = 20.010(7) ?, β = 102.856(14)o, V = 3325(2) ?~3, Z = 4, C_(34)H_(32)CoO_(15), M_r = 739.53, D_c = 1.477 g/cm^3, F(000) = 1532, μ = 0.591 mm^(-1), R = 0.1123 and w R = 0.1419. In the crystal structure, the Co(Ⅱ) shows 6 coordination geometry, and the flavonoid ligand coordinated with the Co(Ⅱ) ion in a monodentate mode. Hydrogen bonding interactions and π-π stacking interactions lead to the three-dimensional stacking of crystal and increase its stability. Moreover, the thermal stability and luminescent properties of the complex are also investigated. The fluorescence of the complex shows a great reduction of the intensity than that of the ligand.

关键词： cobalt(Ⅱ) crystal structure water-bridged polymer flavonoid spectral property

Genetic characteristics of a patient with multiple primary cancers:A case report

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World Journal of Clinical Cases 2021年第28期9卷 8563-8570页

作者： wei-wei Ouyang Qing-yun Li Wen-Gang yang Sheng-Fa Su Li-Jia Wu Ying yang Bing Lu Department of Thoracic Oncology The Affiliated Hospital of Guizhou Medical University and Cancer Hospital of Guizhou Medical UniversityGuiyang 550000Guizhou ProvinceChina Genecast Biotechnology Co. LtdWuxi 214104Jiangsu ProvinceChina

BACKGROUND Two or multiple primary malignant neoplasms(MPMNs)rarely occur in the same *** has been reported that MPMNs are easily misdiagnosed as the recurrence or metastasis of malignancies in clinical practice,affecting the choice of treatment for the patients,thereby resulting in the delay of optimal *** generation sequencing(NGS)can be used to distinguish between multiple primary lung cancers and intrapulmonary metastasis,and may distinguish the origin of tumours in different sites of the *** SUMMARY We report the case of 66-year-old woman who suffered from different malignant neoplasms in the rectum and esophageal and gastrointestinal *** first neoplasm rectal adenocarcinoma was diagnosed and removed in *** second and third lesions were diagnosed with esophageal squamous-cell carcinoma(ESCC)and gastrointestinal stromal tumour(GIST),respectively,in *** whole exome sequencing was performed on the tissue specimens of rectal carcinoma,esophageal cancer,GIST,and white blood cells to investigate the relationship between malignancies at different timeframe and determine whether the ESCC and GIST evolved from the rectal *** including v-Ki-ras2-Kirsten rat sarcoma viral oncogene homolog,adenomatosis polyposis coli,and mothers against decapentaplegic homolog 4 were detected in rectal adenocarcinoma sample,mast/stem cell growth factor receptor was detected in GIST tissue,and lysine methyltransferase 2D was detected in ESCC ***,ESCC and GIST were not genetically evolved from rectal adenocarcinoma,and this patient did not have a trunk driven *** NGS is an effective tool to study clonal evolution of tumours and distinguish between MPMNs and intrapulmonary metastasis.

关键词： Multiple primary malignant neoplasms Whole exome sequencing Rectal carcinoma Esophageal squamous-cell carcinoma Gastrointestinal stromal tumour Case report