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Preparation of Electrospun PVDF nanofiber Composite Filter Medium and Its Application in Air Filtration

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Paper And Biomaterials 2019年第1期4卷 23-30页

作者： Qi du na Wang Wen Liu xueFeng Chen Yue xu Ying Wan China national Pulp and Paper Research Institute Co. Ltd. Beijing 100102 China national Engineering Laboratory of Pulp and Paper Beijing 100102 China

nanofibrous media with both high particle interception efficiency and robust air permeability has broad technological applications in areas including individual protection, industrial security, and environmental governance. However, producing such filtration media has proven to be extremely challenging. Here we reported an approach to preparing and fabricating a polyvinylidene fluoride (PVDF) nanofiber composite filter medium composed of 2D PVDF nanofiber nets and a stable substrate via onestep electrospinning for effective air filtration. PVDF nanofibers are obtained by adjusting the electrospinning process. With the combined properties of ultrasmall diameter, high porosity, and a bonded scaffold, the resulting PVDF nanofiber composite filter medium exhibits a robust high filtration efficiency of 99.901%(equivalent to an F9 rating) for 0.4 mm particles and a long service life (a large dust holding capacity of 36 g/m^2) for ultrafine airborne particles based on the sieving principle and surface filtration behavior. The successful synthesis of PVDF nanofibers medium would not only make it a promising candidate for air filtration, but also provide new insights into the design and development of composite nanofiber structures for various applications.

关键词： electrospinning filtration efficiency nanofiber dust holding capacity air filtration

Secret key generation based on private pilot under man-in-the-middle attack

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Science China(Information Sciences) 2017年第10期60卷 93-106页

作者： Yu HUANG Liang JIN na LI Zhou ZHONG Xiaoming xu national Digital Switching System Engineering and Technological R&D Center national Engineering Laboratory for Mobile Network Technologies Beijing University of Posts and Telecommunications

Given the openness and invariance of public pilot, secret key generation(SKG) based on wireless channels is vulnerable to active attacks. In this paper, we explore man-in-the-middle(MITM) attacks, where the attacker acts as a transparent relay to intercept channel state information and deduce the generated *** prevent this type of attacks, a dynamic private pilot is generated, where legitimate nodes first consider the information authenticated between them as seed information for the private pilot, and then generate the private pilot based on this seed information according to the pilot requirements. Then, both the new seed information and secret keys are dynamicaally derived from wireless channels that are estimated with the private pilot instead of a public pilot. The proposed private pilot encrypts and authenticates wireless channels, allowing an SKG rate close to that without attackers. Analysis and simulation results show that the proposed SKG approach can effectively withstand an MITM attack.

关键词： private pilot man-in-the-middle attack secret key generation physical layer security

Recovery of scandium from bauxite residue——red mud:a review

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Rare Metals 2016年第12期35卷 887-900页

作者： na Zhang Hong-xu Li Xiao-Ming Liu School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction University of Science and Technology Beijing

Red mud is a slimy caustic residue generated from alumina production. Taking into account the rela- tively considerable content and availability of scandium, red mud can be viewed as an important and promising scandium resource rather than a solid waste. This paper is primarily to review the investigations of scandium recov- ery from red mud based on the most widely used hydrometallurgical processes including acid leaching, sol- vent extraction and ion exchange adsorption. It is thought that recovery of scandium from red mud should be con- sidered as a direct objective rather than a by-product in the development of overall flowsheet. In order to achieve environmentally-friendly processes with high scandium recovery and low cost, more attention is required to be paid to optimizing the selective leaching of scandium to decrease mineral acid consumption and alleviate pollution, and developing new solvent extraction systems and novel ion exchange adsorption materials with high selectivity and recognition for scandium.

关键词： Red mud Scandium Acid leaching Solvent extraction Ion exchange Selectivity

Hollow-glass-microsphere-based Biphenyl Epoxy Resin Composite with Low Dielectric Contant

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Chemical Research in Chinese Universities 2018年第5期34卷 862-866页

作者： xu Weiwei na Hui ZHAO Chengji Center of Metrology Datang Northeast Electric Power Test & Research Institute Co. Ltd. Changchun 130012 P. R. China College of Chemistry Jilin University Changchun 130012 P. R. China

In this study, rigid 4,4＇-diglycidyl（3,3＇,5,5＇-tetramethylbiphenyl） epoxy（TMBP）-based composites were developed by the incorporation of varying percentages of commercial hollow glass microspheres（HGMs, QH-450） into the TMBP resin used for electronic packaging. The thermal and mechanical properties as well as the morphology of all the composites were characterized, and dielectric properties were characterized by advanced analytical techniques. The results reveal that a series of TMBP/QH-450 composites exhibits higher initial degradation tempera- tures（Td, s,/o〉300 ~C）, and the residual char and glass transition temperature were clearly improved with QH-450 loading. In addition, all epoxy composites exhibited a lower dielectric constant ranging from 3.74 to 3.06 at 1.2 MHz because the lower dielectric properties of the inert gas used as the core of the QH-450 decreased molecule polarity. Hence, this developed TMBP/QH450 system demonstrates potential applications in electronic packaging.

关键词： Biphenyl Thermal property Polymer composite Dielectric constant

Simulating Calculation of Frictional Force between Mold and Billet

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Journal of Iron and Steel Research International 1998年第1期5卷 13-16页

作者： xu Guangming Cui Jianzhong na Xinjie Northeastern University

Assumption about the inner surface of mold is made according to the forming mechanisms of frictional force. The frictional force between billet and mold can be analysed by calculating the thermal shrinkage and the shearing strength of the *** model is used to calculate the maximum drawing speed at different conditions. The results are very satisfactory.

关键词： simulating calculation frictional force mold billet

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A low redox potential and long life organic anode material for sodium-ion batteries

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Journal of Energy Chemistry 2025年第1期100卷 557-564页

作者： Zhi Li Yang Wei Kang Zhou Xin Huang Xing Zhou Jie xu Taoyi Kong Junwei Lucas Bao Xiaoli Dong Yonggang Wang Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Institute of New Energy Collaborative Innovation Center of Chemistry for Energy Materials (iChEM) Fudan University Department of Chemistry Boston College School of Materials Science and Engineering Anhui University of Technology

Sodium-ion batteries （SIBs） with organic electrodes are an emerging research direction due to the sustainability of organic materials based on elements like C,H,O,and sodium ***,organic electrode materials for SIBs are mainly used as cathodes because of their relatively high redox potentials（>1 V）.Organic electrodes with low redox potential that can be used as anode are ***,a novel organic anode material （tetrasodium 1,4,5,8-naphthalenetetracarboxylate,na4TDC） has been developed with low redox potential （na4TDC-hard carbon composite can further acquire improved capacity and cycling stability for 1200 cycles even with a high mass loading of up to 20 mg *** pairing with a thick na3V2（PO4）3cathode (20.6 mg cm-2),the as-fabricated full cell exhibited high operating voltage （2.8 V）,excellent rate performance and cycling stability with a high capacity retention of 88.7% after 200 cycles,well highlighting the na4TDC anode material for SIBs.

关键词： Organic anode material Low redox potential Composite anode Sodium-ion batteries

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预处理工艺对皂荚籽脱壳性能的影响

农机化研究 2025年第3期47卷 162-168页

作者：李娜李姜维徐鹏云线承源王杉河北农业大学机电工程学院河北保定071000 河北省智慧农业装备技术创新中心河北保定071001

针对人工剥离皂荚米功效低、成本高,以及现有皂荚籽机械化脱壳装置去壳过程繁琐、脱壳不充分,需循环脱壳且脱壳率低的问题,以分级后安徽省亳州市产皂荚籽为研究对象,提出了一种通过一定浓度的塔塔粉蒸煮皂荚籽后再烘干的预处理工艺。通... 详细信息

针对人工剥离皂荚米功效低、成本高,以及现有皂荚籽机械化脱壳装置去壳过程繁琐、脱壳不充分,需循环脱壳且脱壳率低的问题,以分级后安徽省亳州市产皂荚籽为研究对象,提出了一种通过一定浓度的塔塔粉蒸煮皂荚籽后再烘干的预处理工艺。通过自主设计的碾搓式皂荚籽脱壳装置,以脱壳率为评价指标,通过单因素试验和正交试验,分析蒸煮时间、塔塔粉浓度与烘干时间在不同水平下的脱壳效果。试验结果表明:随着塔塔粉浓度的增大,脱壳率先增大后减小;随着蒸煮时间和烘干时间的增加,脱壳率逐渐增大后再逐渐趋于平稳。通过Design-Expert软件分析试验数据,结果显示:对皂荚籽脱壳率影响显著性由小到大的顺序为蒸煮时间、烘干时间、塔塔粉浓度。建立皂荚籽脱壳的回归数学模型并优化求解一组最优参数组合,即蒸煮时间为90 min,塔塔粉浓度为3%,烘干时间为8 h,此条件下脱壳率达到84.42%。

关键词：皂荚籽预处理工艺脱壳率

Transverse mode-coupling instability with longitudinal impedance

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Nuclear Science and Techniques 2024年第6期35卷 40-53页

作者： Hai-Sheng xu Chun-Tao Lin na Wang Jing-Ye xu Yuan Zhang Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China Institute of Advanced Science Facilities Shenzhen 518107GuangdongChina

Transverse mode-coupling instability(TMCI)is a dangerous transverse single-bunch instability that can lead to severe par-ticle *** mechanism of TMCI can be explained by the coupling of transverse coherent oscillation modes owing to the transverse short-range wakefield(i.e.,the transverse broadband impedance).Recent studies on future circular colliders,e.g.,FCC-ee,showed that the threshold of TMCI decreased significantly when both longitudinal and transverse impedances were *** performed computations for the circular electron-positron collider(CEPC)and observed a similar *** studies on the influence of longitudinal impedance on the TMCI threshold were *** concluded that the imaginary part of the longitudinal impedance,which caused a reduction in the incoherent synchrotron tune,was the primary reason for the reduction in the TMCI ***,the real part of the longitudinal impedance assists in increasing the TMCI threshold.

关键词： Transverse mode-coupling instability Longitudinal impedance

Optimization Strategies of na_(3)V_(2)(PO_(4))_(3) Cathode Materials for Sodium‑Ion Batteries

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nano-Micro Letters 2025年第2期17卷 204-251页

作者： Jiawen Hu Xinwei Li Qianqian Liang Li xu Changsheng Ding Yu Liu Yanfeng Gao School of Materials Science and Engineering Shanghai UniversityShanghai 200444People’s Republic of China Shanghai Institute of Ceramics Chinese Academy of SciencesShanghai 200050People’s Republic of China

na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural ***,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in ***,it is of significance to boost the sodium storage performance of NVP cathode *** to now,many methods have been developed to optimize the electrochemical performance of NVP cathode *** this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology *** foreign-ion doping or substitution is highlighted,involving na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so ***,the challenges and prospects of high-performance NVP cathode material are also put *** is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.

关键词： Sodium-ion batteries na_(3)V_(2)(PO_(4))_(3) Cathode materials Electrochemical performance Optimization strategies