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Molecular Chain Flexibility and Dielectric Loss at High-Frequency:Impact of Ester Bond Arrangement in Poly(ester imide)s

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Chinese Journal of Polymer Science 2024年第8期42卷 1122-1133页

作者： Ya-Dong Li Hong Li Lu-Kun Feng Feng Bao Ming-Liang Wang Cai-Zhen Zhu Zhao-Hui Zheng xiao-bin ding Jian Xu Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100081China Institute of Low-Dimensional Materials Genome Initiative College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China

The evolution of high-frequency communication has accentuated the significance of controlling dielectric properties in polymer ***,it has been theorized that rigid molecular chains lead to lower dielectric ***,the validity of this proposition at high frequencies remains *** scrutinize the correlation between chain flexibility and dielectric properties,we synthesized six poly(ester imide)s(PEIs)with systematically varied molecular chain flexibilities by modifying the ester's substitution on the aromatic *** introduction of ester bonds bestowed all PEI films with a low dielectric dissipation factor(D_(f)),ranging from 0.0021 to 0.0038 at 10 GHz in dry *** dry D_(f)displayed a pattern consistent with volume polarizability(P/V).Unexpectedly,PI-mmm-T,featu ring the most flexible molecular chain,exhibited the lowest dielectric loss under both dry(0.0021@10 GHz)and hygroscopic(0.0029@10 GHz)***,the observed increase in D_(f)after humidity absorption suggests that the high dielectric loss of PEI in applications may be attributed to its hygroscopic *** simulations and characterization of the aggregation structure revealed that the smaller cavities within flexible molecular chains,after close stacking,impede the entry of water *** sacrificing high-temperature resistance,the precursor exhibited enhanced solubility properties and could be processed into high-quality *** research unveils new insights into the relationship between flexibility and highfrequency dielectric loss,offering innovative perspectives on synthesizing aromatic polymers with exceptional dielectric properties.

关键词： 5G communications Poly(ester imide)s Molecular chain flexibility Dielectric properties Humidity absorption

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Hybrid Composite of Polyaniline Containing Carbon Nanotube

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Chinese Chemical Letters 2001年第11期12卷 1037-1040页

作者： Jian Guo DENG xiao bin ding Yu Xing PENG Albert SCCHAN Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041 Open Laboratory of Chirotechnology and Department of Applied Biology and Chemical Technology Hong Kong Polytechnic UniversityHong Kong

Carbon nanotube-polyaniline hybrid material was synthesized by emulsion polymerization in-situ. The morphology of hybrid material was studied by TEM and X-ray diffraction. The conductivity of nanocomposite increases with the increasing of carbon nanotube content because of the new conductivity passageways formed by carbon nanotubes.

关键词： carbon nanotube polyaniline hybrid material

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Synthesis of Molecularly Imprinted Polymer Particles by Suspension Polymerization in Silicon Oil

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Chinese Chemical Letters 2006年第9期17卷 1243-1246页

作者： xiao bing WANG Zhao Hui ZHENG xiao bin ding Xu CHENG Xin Hua HU Yu Xing PENG Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu 610041 Graduate School of the Chinese Academy of Sciences Beijing 100081

Molecularly imprinted polymers using 2,4-dichlorophenoxyacetic acid （2,4-D） as templates were prepared by suspension polymerization in silicon oil. The polymer particles exhibited regular shape in the micro-scale range. The adsorbing experiments indicated that the imprinted polymer particles possessed higher affinity to 2,4-D than the non-imprinted polymer particles.

关键词： Molecularly imprinted polymer particles suspension polymerization silicon oil.

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Fast synthesis of dopamine-coated Fe_3O_4 nanoparticles through ligand-exchange method

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Chinese Chemical Letters 2012年第9期23卷 1099-1102页

作者： Peng An Fang Zuo Yuan Peng Wu Jun Hua Zhang Zhao Hui Zheng xiao bin ding Yu Xing Peng Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChina Chengdu 610041 Graduate School of the Chinese Academy of Sciences China Beijing 100049 State Key Laboratory of Polymer Materials and Engineering of China Polymer Research InstituteSichuan UniversityChina Chengdu 610065 College of Chemistry&Environment Protection Engineering Southwest University for NationalitiesChina Chengdu 610041 State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation So0uthwest Petroleum University(SWPU)China Chengdu 610500

A fast approach was described for the synthesis of water-dispersible monodisperse dopamine-coated Fe304 nanoparticles （DA- Fe304） with uniform size and shape via ligand-exchange of oleic acid on Fe304 using only 2 min. The prepared DA-Fe304 nanoparticles were characterized by transmission electron microscopy, Fourier transform infrared spectrometry, and vibrating sample magnetometer. The results indicated that the resulting DA-Fe304 nanoparticles had an average diameter of about 19.2 nm. The magnetic saturation value of the prepared DA-Fe304 nanoparticles was determined to be 72.87 emu/g, which indicating a well- established superparamagnetic property.

关键词： Magnetic nanoparticles Fe304 Dopamine Ligand-exchange

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Atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering correction

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Nuclear Science and Techniques 2024年第3期35卷 40-52页

作者： ding-Han Zhu Xiong Zhang xiao-Qiang Li Peng Li Yan-bin Wang Shuang Zhang State Key Laboratory of NBC Protection for Civilian Beijing 102205China

In high-altitude nuclear detonations,the proportion of pulsed X-ray energy can exceed 70%,making it a specific monitoring signal for such *** pulsed X-rays can be captured using a satellite-borne X-ray detector following atmospheric *** quantitatively analyze the effects of different satellite detection altitudes,burst heights,and transmission angles on the physical processes of X-ray transport and energy fluence,we developed an atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering *** proposed method is an improvement over the traditional analytical method that only computes direct-transmission *** traditional analytical method exhibits a maximum relative error of 67.79% compared with the Monte Carlo *** improved method reduces this error to within 10% under the same conditions,even reaching 1% in certain ***,its computation time is 48,000 times faster than that of the Monte Carlo *** results have important theoretical significance and engineering application value for designing satellite-borne nuclear detonation pulsed X-ray detectors,inverting nuclear detonation source terms,and assessing ionospheric effects.

关键词： High-altitude nuclear detonation Atmospheric transmission Pulsed X-rays Scattering correction Analytical method Monte Carlo method

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A brand new green coating technology for realizing the regulation of spherical propellant energy release process

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Defence Technology（防务技术） 2024年第6期36卷 78-94页

作者： Wenhao Fan Yajun ding Zhongliang xiao School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing210094China Key Laboratory of Special Energy Materials Nanjing University of Science and TechnologyMinistry of EducationNanjing 210094China

To achieve the controllable release of energy of nitrocellulose-based propellants,this paper combines the cellulose-based nanocomposites aqueous coating(Surelease®-NC)with fluidized bed coating equipment to successfully prepare the coated spherical propellant for the first *** effects of fluidized bed coating temperature,air velocity,flow speed and atomization pressure on the adhesion rate,coating integrity and coating uniformity of the coated spherical propellant were investigated,and the preparation of coated spherical propellant with homogeneous size and structural integrity was achieved for the first *** microscopic morphology,chemical structure,water vapor adsorption behavior,combustion performance,and ageing resistance property of the coated spherical propellant were systematically investigated by,Fourier transforms infrared spectroscopy(FTIR),Micro confocal raman spectrometer,field scanning electron microscopy(SEM),dynamic vapor adsorption techniques,and closed bomb test,confirming the surface core-shell structure and the tightly bonded interfacial structure of coated spherical ***,the coated spherical propellant has good hygroscopic,excellent progressive burning and long storage stability.

关键词： Nanocomposites aqueous coating Fluidized bed coating equipment Coated spherical propellant Controllable release of energy Long storage stability

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Numerical evaluations on the fluid production in the in-situ conversion of continental shale oil reservoirs

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Petroleum Science 2024年第4期21卷 2485-2501页

作者： Zhao-bin Zhang Maryelin Josefina Brice?o Montilla Shou-ding Li xiao Li Jian-Peng Xing Yan-Zhi Hu Key Laboratory of Shale Gas and Geoengineering Institute of Geology and Geophysics Chinese Academy of Sciences Institute of Earth Sciences Chinese Academy of Sciences College of Earth and Planetary Sciences University of Chinese Academy of Sciences Institute of Energy Peking University

In-situ conversion presents a promising technique for exploiting continental oil shale formations,characterized by highly fractured organic-rich rock. A 3D in-situ conversion model, which incorporates a discrete fracture network, is developed using a self-developed thermal-flow-chemical(TFC) *** of the model elucidates the in-situ conversion process in three stages and defines the transformation of fluids into three distinct outcomes according to their end stages. The findings indicate that kerogen decomposition increases fluid pressure, activating fractures and subsequently enhancing permeability. A comprehensive analysis of activated fracture permeability and heating power reveals four distinct production modes, highlighting that increasing heating power correlates with higher cumulative fluid production. Activated fractures, with heightened permeability, facilitate the mobility of heavy oil toward production wells but hinder its cracking, thereby limiting light hydrocarbon ***, energy efficiency research demonstrates the feasibility of the in-situ conversion in terms of energy utilization, especially when considering the surplus energy from high-fluctuation energy sources such as wind and solar power to provide heating.

关键词： In-situ conversion Continental shale oil Natural fracture network TFC model

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Analytical model for predicting time-dependent lateral deformation of geosynthetics-reinforced soil walls with modular block facing

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 711-725页

作者： Luqiang ding Chengzhi xiao Feilong Cui School of Civil and Transportation Engineering Hebei University of TechnologyTianjin300401China

To date,few models are available in the literature to consider the creep behavior of geosynthetics when predicting the lateral deformation(d)of geosynthetics-reinforced soil(GRS)retaining *** this study,a general hyperbolic creep model was first introduced to describe the long-term deformation of geosynthetics,which is a function of elapsed time and two empirical parameters a and *** conventional creep tests with three different tensile loads(Pr)were conducted on two uniaxial geogrids to determine their creep behavior,as well as the a-Pr and b-Pr *** test results show that increasing Pr accelerates the development of creep deformation for both ***,a and b respectively show exponential and negatively linear relationships with Pr,which were confirmed by abundant experimental data available in other *** on the above creep model and relationships,an accurate and reliable analytical model was then proposed for predicting the time-dependent d of GRS walls with modular block facing,which was further validated using a relevant numerical investigation from the previous *** evaluation and comparison of the proposed model with six available prediction models were *** a parametric study was carried out to evaluate the effects of wall height,vertical spacing of geogrids,unit weight and internal friction angle of backfills,and factor of safety against pullout on d at the end of construction and 5 years *** findings show that the creep effect not only promotes d but also raises the elevation of the maximum d along the wall ***,the limitations and application prospects of the proposed model were discussed and analyzed.

关键词： Geosynthetics Creep behavior Geosynthetics-reinforced soil(GRS)walls Lateral deformation Analytical model

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Industry-Oriented Detection Method of PCBA Defects Using Semantic Segmentation Models

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1438-1446页

作者： Yang Li xiao Wang Zhifan He Ze Wang Ke Cheng Sanchuan ding Yijing Fan xiaotao Li Yawen Niu Shanpeng xiao Zhenqi Hao bin Gao Huaqiang Wu Department of Internet of Things Technology and Application China Mobile Research InstituteBeijing 100053China Beijing Advanced Innovation Center for Integrated Circuits the School of Integrated CircuitTsinghua UniversityBeijing 100084China SigmaStar Technology Limited Xiamen 361199China IEEE

Automated optical inspection(AOI)is a significant process in printed circuit board assembly(PCBA)production lines which aims to detect tiny defects in *** AOI equipment has several deficiencies including low throughput,large computation cost,high latency,and poor flexibility,which limits the efficiency of online PCBA *** this paper,a novel PCBA defect detection method based on a lightweight deep convolution neural network is *** this method,the semantic segmentation model is combined with a rule-based defect recognition algorithm to build up a defect detection *** improve the performance of the model,extensive real PCBA images are collected from production lines as *** optimization methods have been applied in the model according to production demand and enable integration in lightweight computing *** results show that the production line using our method realizes a throughput more than three times higher than traditional *** method can be integrated into a lightweight inference system and pro-mote the flexibility of *** proposed method builds up a general paradigm and excellent example for model design and optimization oriented towards industrial requirements.

关键词： Automated optical inspection(AOI) deep learning defect detection printed circuit board assembly(PCBA) semantic segmentation.

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Hybrid Network Model Based on Data Enhancement for Short-term Power Prediction of New PV Plants

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 77-88页

作者： Shangpeng Zhong xiaoming Wang bin Xu Hongbin Wu Ming ding the Anhui Province Key Laboratory of Renewable Energy Utilization and Energy Saving Hefei University of TechnologyHefei 230009China the State Grid Anhui Electric Power Research Institute Hefei 230061China

This study proposes a hybrid network model based on data enhancement to address the problem of low accuracy in photovoltaic(PV)power prediction that arises due to insuffi cient data samples for new PV ***,a time-series gener ative adversarial network(TimeGAN)is used to learn the distri bution law of the original PV data samples and the temporal correlations between their features,and these are then used to generate new samples to enhance the training ***,a hybrid network model that fuses bi-directional long-short term memory(BiLSTM)network with attention mechanism(AM)in the framework of deep&cross network(DCN)is con structed to effectively extract deep information from the origi nal features while enhancing the impact of important informa tion on the prediction ***,the hyperparameters in the hybrid network model are optimized using the whale optimi zation algorithm(WOA),which prevents the network model from falling into a local optimum and gives the best prediction *** simulation results show that after data enhance ment by TimeGAN,the hybrid prediction model proposed in this paper can effectively improve the accuracy of short-term PV power prediction and has wide applicability.

关键词： New photovoltaic(PV)plant short-term predic tion time-series generative adversarial network(TimeGAN) hy brid network hyperparameter

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