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A Facile Strategy for Intrinsic Low-Dk and Low-Df Polyimides Enabled by Spirobifluorene Groups

Chinese Journal of Polymer Science 2023年第2期41卷 288-296页

作者： Wan-Yi Tan Ling-Feng Jian Wei-Peng Chen Yong-Wen Zhang Xiao-Chuang Lu Wan-Jun Huang Ji-Sheng Zhang Jing-Wu Wu Jun-Li Feng Yi-Dong Liu Ting-Ting Cui Yong-Gang Min Guangdong University of Technology(GDUT) Guangzhou510006China Huimai Materials Technology(Guangdong)Co. Ltd.Foshan528200China Shenzhen Customs Industrial Product inspection Technology center Shenzhen518026China

Modified polyimides(MPIs)show great potential towards 5G communication applications,due to its excellent thermal stability,mechanical property and chemical stability as compared to most of *** fluoride groups or porous structure is favorable to ultra-low dielectric constant(D_(k))and dielectric loss(D_(f)).However,the cost of the fluorinated MPIs is high and their synthetic processes are complicated,and porous MPIs suffer poor mechanical ***,increasing the fraction of free volume is a very effective way to lower D_(k)through introducing more ultra-low-D_(k)air ***,most of this kind of MPIs lag far behind the fluorinated MPIs and the porous MPIs in terms of ultra-low D_(f),hindering the application of MPIs in high-speed communication ***,it is highly desirable to develop intrinsic ultra-low-D_(k)/D_(f)MPIs at high frequency with less fluoric groups and nonporous ***,we introduce a facile and effective strategy to lower D_(k)and D_(f)through introducing rigid and large sterically hindered aromatic groups into *** the one hand,their large steric hindrance effect leads to low D_(k)by increasing intrinsic free *** the other hand,the resulting highly stiff polymer chain and strong intermolecular interaction are favorable to reduce D_(f)by inhibiting dipole *** on this strategy,the spirobifluorene groups are *** as-prepared MPIs show excellent dielectric performance with low D_(k)of 2.74–2.76 and low D_(f)of 0.00599 at 10 GHz,to some extent,exceeding the multiple fluorinated MPI with D_(k)/D_(f)of 2.67/0.00663 at 10 GHz.

关键词： Polyimide High speed communication Low dielectric constant Low dielectric loss

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Prediction of Cross-Tension Strength of Self-Piercing Riveted Joints Using Finite Element Simulation and XGBoost Algorithm

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Chinese Journal of Mechanical Engineering 2021年第2期34卷 168-178页

作者： Jianping Lin Chengwei Qi Hailang Wan Junying Min Jiajie Chen Kai Zhang Li Zhang School of Mechanical Engineering Tongji UniversityShanghai 201804China Pan Asia technical Automotive center Shanghai 202106China

Self-piercing riveting(SPR)has been widely used in automobile industry,and the strength prediction of SPR joints always attracts the attention of *** this work,a prediction method of the cross-tension strength of SPR joints was proposed on the basis of finite element(FE)simulation and extreme gradient boosting decision tree(XGBoost)*** FE model of SPR process was established to simulate the plastic deformations of rivet and substrate materials and verified in terms of cross-sectional dimensions of SPR *** residual mechanical field from SPR process simulation was imported into a 2D FE model for the cross-tension testing simulation of SPR joints,and cross-tension strengths from FE simulation show a good consistence with the experiment *** on the verified FE model,the mechanical properties and thickness of substrate materials were varied and then used for FE simulation to obtain cross-tension strengths of a number of SPR joints,which were used to train the regression model based on the XGBoost algorithm in order to achieve prediction for cross-tension strength of SPR *** show that the cross-tension strengths of SPR steel/aluminum joints could be successfully predicted by the XGBoost regression model with a respective error less than 7.6%compared to experimental values.

关键词： Self-piercing riveting Joint strength Cross-tension Finite element modeling Machine learning

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Mechanical properties of molybdenum products prepared by using molybdenum powders with different micro-morphologies

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Rare Metals 2015年第4期34卷 276-281页

作者： Geng An Jun Sun Ren-Zhi Liu Jing Li Yuan-Jun Sun State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University technical center Jinduicheng Molybdenum Co. Ltd

Using two kinds of molybdenum （Mo） powders with different micro-morphologies as raw materials, the Mo wires with a diameter of 0.18 mm and Mo sheets with thickness of 0.5 and 0.2 mm were prepared at the same process of pressing, sintering, drawing, or rolling, respectively. By comparative analysis on the microstructure and mechanical properties of Mo wires and Mo sheets, the effect of Mo powder micro-morphology on properties and quality of Mo products was studied. The results show that, compared with that prepared by traditional Mo powder with inhomogeneous particle size and aggregation, the Mo wires prepared by specific Mo powder with homogeneous particle sizes, less agglomeration, and better dispersion exhibit higher yield, higher tensile strength, and lower elongation at room temperature, and the Mo sheets also show excellent high-temperature performances and better isotropy. The essential reason for those is the difference of Mo powder micro-morphology. Inhomogeneous particle size and aggregation of Mo powder greatly influence the microstructure of Mo sintered compacts and mechanical properties of Mo products.

关键词： Molybdenum powder Micro-morphology Aggregation Molybdenum product Mechanical property

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An Eulerian SPH method with WENO reconstruction for compressible and incompressible flows

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Journal of Hydrodynamics 2023年第2期35卷 210-221页

作者： Zhentong Wang Chi Zhang Oskar J.Haidn Xiangyu Hu TUM School of Engineering and Design Technical University of MunichMunichGermany Huawei Technologies Munich Research center MunichGermany

While Eulerian smoothed particle hydrodynamics(SPH)method has received increasing attention in scientific and industrial communities owing to its high spatial accuracy,it exhibits excessive numerical dissipation due to the fact that the flux is derived in particle pair *** this paper,we adopt a one-dimensional weighted essentially non-oscillatory(WENO)reconstruction to reduce the numerical dissipation and improve the overall accuracy particularly in capturing the contact *** underlying principle is to construct a 4-point stencil along the interacting line of each particle pair and then the WENO scheme is applied to reconstruct the initial states of the Riemann problem which determines the flow flux.A set of benchmark tests for both compressible and incompressible flows are studied to investigate the accuracy,robustness and versatility of the proposed Eulerian SPH method with the WENO reconstruction(ESPH-WENO).

关键词： Eulerian smoothed particle hydrodynamics(SPH) compressible flows incompressible flows Riemann problem

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Flight inspection Analysis on National Cosmetics in 2018

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China Detergent & Cosmetics 2019年第4期4卷 46-50页

作者： Jia Na center for Food and Drug inspection of NMPA

In this article,the author briefly introduced the causes of cosmetics flight inspection and analyzed the national cosmetics flight inspection in ***,the author proposed the corresponding production quality management suggestions,offered reference for enterprises and helped businesses to improve the capability of production quality *** so doing,the corporate responsibility awareness could be established so as to guarantee the quality and safety of cosmetics.

关键词： nation cosmetics flight inspection analysis

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Identification and Characterization of MicroRNAs and Their Targets in Grapevine(Vitis vinifera)

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Agricultural Sciences in China 2008年第8期7卷 929-943页

作者： LU Yan-du GAN Qin-hua CHI Xiao-yuan QIN Song Yantai Institute of Coastal Zone Research for Sustainable Development Chinese Academy of Sciences Yantai 264003 P.R.China Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 P.R.China Graduate School Chinese Academy of Sciences Beijing 100049 P.R.China technical center of inspection and Quarantine Shandong Entry-Exit Inspection and Quarantine Bureau Qingdao 266001 P.R.China

MicroRNAs （miRNAs） are a class of newly identified, small, non-coding RNAs that play vital roles in regulation. Based on miRNAs unique features of expression pattern, evolutionary conservation, secondary structure and genetic requirements for biogenesis, computational predication strategy is adopted to predicate the novel miRNAs. In this research, potential miRNAs and their targets in grapevine （Vitis vinifera） were predicted. We used previously known plant miRNAs against grapevine genome sequence databases to search for potential miRNAs. A total of 81 potential miRNAs were detected following a range of strict filtering criteria. Using these potential miRNA sequences, we could further blast the mRNA database to find the potential targets in this species. Comparative analysis of miRNAs in grapevine and other species reveals that miRNAs exhibit an evolutional conservation, the number and function of miRNAs must have significantly expanded during the evolution of land plants. Furthermore divergence made versatile functions of miRNAs feasible. Cluster of miRNAs likely represents an ancient expression mechanism. Predicted target genes include not only transcription factors but also genes implicated in floral development, signal transduction, diseases and stress response. Till now, little is known about experimental or computational identification of miRNA in grapevine species. Increased knowledge of the biological mechanisms of the grapevine will allow targeted approaches to increase the quality of fruit and reduce the impact of parasites together with stress, which could enable a sustainable, environmentally-sound, farming policv.

关键词： microRNAs prediction targets Vitis vinifera evolution floral development

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Crystal Structure of Lithium Yttrium Borate LiY_6O_5(BO_3)_3

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Chinese Journal of Structural Chemistry 2006年第10期25卷 1175-1178页

作者： GAO Jian-Hua Beijing center for Crystal Research and Development Technical Institute of Physics and Chemistry The Chinese Academy of Sciences Beijing 100080 China

Single crystals of LiY6O5（BO3）3 were obtained by the flux method and its structure was determined by a four-circle automatic diffractometer with a MoKα radiation. It crystallizes in monoclinic, space group P21/n with a = 8.330（3）, b = 15.444（4）, c = 8.780（3）°A,β = 91.85（3）°, V = 1129.0（6）°A^3, Z = 4, Mr= 796.83, F（000） = 1456, μ = 30.567 mm^-1, Dc= 4.688 g/cm^3, the final R = 0.0722 and wR = 0.1304. It exhibits a three-dimensional fiamework of yttrium-oxygen polyhedra interconnected by common edges and corners. B and Li atoms are located in the planes and cavities formed by oxygen atoms, respectively.

关键词： borate lithium yttrium borate single-crystal structure VUV luminescent materials

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Effect of Preload Force on Heat Generation of Li(Ni_(0.8)Co_(0.1)Mn_(0.1))O_(2)/SiO_(x)-C System Batteries:The Discharge Process

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Journal of Thermal Science 2024年第5期33卷 1809-1825页

作者： LIN Chunjing LAI Zhenxing BAI Guangli MA Biao WEI Zhen QI Chuang LIU Shiqiang Key Laboratory of Advanced Manufacturing Technology for Automobile Parts Ministry of EducationChongqing University of TechnologyChongqing 400054China China Auto Research New Energy Vehicle inspection center(Tianjin)Co Tianjin 300300China

Lithium-ion batteries(LIBs)undergo various degradation phenomena such as material decomposition,structural change and uneven lithium ion distribution during long-term cycles,which would affect their performance and *** order to improve the performance of the LIBs during their life cycle,preload force is preset when the batteries are *** preload forces will in turn affect the cycle life and heat generation of the *** order to address this issue,this work carries out charge/discharge cycle tests on a NCM811 battery under different preload *** calorimetry tests are performed to investigate the battery heat generation under different states of health(SOHs)and preload *** on the test results,an empirical prediction model for heat generation power as a function of SOH is *** show that when the preload force is 5 N·m,the battery capacity decreases in the slowest rate and the average heat generation power is the *** in peaks of the incremental capacity curve can be used to characterize the loss of lithium at the electrode,which in turn characterizes the change of heat generation power of the *** average heat generation power is mainly affected by the SOH,going through a period of trough with the decrease of the SOH and continuing to increase after crossing the critical *** general,these findings emphasize the relationship between preload force,SOH and heat generation power,which is helpful for the judgment of optimal preload to improve the efficiency of LIBs.

关键词： lithium ion battery cyclic aging preload force heat generation characteristic

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Research on the On-line Monitoring System of Battery Power

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International Journal of Technology Management 2015年第2期 31-33页

作者： Leilei XIE Youyu CHEN Long XIN Shanghai Institute of Quality Inspection and Technical Research Institute 201114China

Through the comparison of various acquisition technology and related technology theory of the existing scheme, the paper analyze and design the power battery testing platform of the data acquisition system, and give the research design scheme of the utility model through the design of the software on PC and CAN bus, which makes the full synchronization requirements acquisition unit; improve the linearity and stability of total voltage and current acquisition by the integrated circuit, and improve the system sampling rate, effectively complete the corresponding index. Finally, through experimental verification, to ensure the completion of the technical indicators.

关键词： Single data acquisition CAN AH and WH metering power battery

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Metagenomic insights into microorganisms and antibiotic resistance genes of waste antibiotic fermentation residues along production,storage and treatment processes

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Journal of Environmental Sciences 2024年第2期136卷 45-55页

作者： Ziming Han Xiao Luan Haodi Feng Yanqin Deng Min Yang Yu Zhang State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China National Engineering Research center of Industrial Wastewater Detoxication and Resource Recovery Beijing 100085China Wuhan Agricultural inspection center Wuhan 430016China University of Chinese Academy of Sciences Beijing 100049China

Antibiotic fermentation residue(AFR)is nutrient-rich solid waste generated from fermentative antibiotic production *** is demonstrated that AFR contains high-concentration of remaining antibiotics,and thus may promote antibiotic resistance development in receiving environment or feeding farmed ***,the dominate microorganisms and antibiotic resistance genes(ARGs)in AFRs have not been adequately explored,hampering understanding on the potential antibiotic resistance risk development caused by ***,seven kinds of representative AFRs along their production,storage,and treatment processes were collected,and multiple methods including amplicon sequencing,metagenomic sequencing,and bioinformatic approaches were adopted to explore the biological characteristics of *** expected,antibiotic fermentation producer was found as the predominant species in raw AFRs,which were collected at the outlet of fermentation ***,except for producer species,more environment-derived species persisted in stored AFRs,which were temporarily stored at a semi-open *** genus,classified as Firmicutes phylum and Bacilli class,became predominant bacterial taxa in stored AFRs,which might attribute to its tolerance to high concentration of *** from metagenomic sequencing together with assembly and binning approaches showed that these newly-colonizing species(e.g.,Lactobacillus genus)tended to carry ARGs conferring resistance to the remaining ***,after thermal treatment,remaining antibiotic could be efficiently removed from AFRs,and microorganisms together with DNA could be strongly *** sum,the main risk from the AFRs was the remaining antibiotic,while environment-derived bacteria which tolerate extreme environment,survived in ARFs with high content antibiotics,and may carry ***,hydrothermal or other harmless treatment technologies are recommended to remove antibiotic content and inactivate bacteria befor

关键词： Pharmaceutical manufacturing Antibiotic mycelia residue Antibiotic resistance bacteria Thermal treatment Solid waste

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