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Fabrication and evaluation of molecularly imprinted regenerated cellulose composite membranes via atom transfer radical polymerization

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Chinese Chemical Letters 2014年第2期25卷 273-278页

作者： Yi-Lin Wu Yong-Sheng Yan Jian-Ming Pan xiao-hui Dai Wei-Dong Shi Min-Jia Meng School of Chemistry and Chemical Engineering Jiangsu University

A simple and effective method for surface molecularly imprinted composite membranes （MICMs） for artemisinin （Ars） based on regenerated cellulose membranes was first prepared through surface- initiated atom transfer radical polymerization （ATRP）, and the as-prepared MICMs were then evaluated as adsorbents for selective recognition and separation of Ars molecules. Batch rebinding studies were conducted to determine the specific adsorption equilibrium, kinetics and selective permeation performance. The adsorption capacity of MICMs toward Ars by the Langmuir isotherm model was 2.008 mgg-1, which was nearly 5.0 times higher than non-molecularly imprinted composite membranes （NICMs）. The kinetic property of MICMs was well-fitted by the pseudo-second-order rate equation. The selective permeation experiments were successfully investigated to prove the excellent selective permeation performance for Ars than the competitive analog （artemether）.

关键词： Molecularly imprinted compositemembranes Atom transfer radical polymerization Selective recognition Artemisinin

Effect of the Addition of High Li Concentration on the Microstructure and Mechanical Properties of Al-Mg-Si Alloys with Different Mg Contents

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Acta Metallurgica Sinica(English Letters) 2021年第12期34卷 1721-1733页

作者： xiao-Kun Yang Bai-Qing Xiong Xi-Wu Li Li-Zhen Yan Zhi-hui Li Yong-An Zhang Ya-Nan Li Kai Wen State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.LtdBeijing 100088China GRIMAT Engineering Institute Co. LTDBeijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China

In the present work,the microstructural characteristics and mechanical properties of Al-1.5 Mg-0.6Si and Al-3.0 Mg-0.6Si alloy containing 3 wt%Li were investigated by optical microscopy(OM),X-ray diffraction analysis(XRD),scanning electron microscopy(SEM),time of flight-secondary ion mass spectrometry(SIMS),transmission electron microscopy(TEM),and mechanical performance *** addition of Li reduces the density of the base alloy by up to 8.4%.The residual second phases contain Mg and Si in the hot-rolled condition,but the Mg/Si atomic ratio decreases after quenching,which means that Li substitute some of the Mg and convert Mg_(2)Si into a(Mg,Li)_(2)Si phase during solution *** results of SIMS observations confirm *** high Mg-containing alloy has a more rapid hardening response compared to the low Mg-containing *** observation reveals that theδ′-Al3Li+β′′-Mg_(2)Si dual phases can be observed in the high Mg-containing alloy after aging for 100 h at 170°*** higher Mg content enhances the precipitation of theδ′phase,which results in the high Mg-containing alloy having a larger average diameter size ofδ′particles and widerδ′-precipitate-free zones(δ′-PFZs).The mechanical properties are significantly improved with the elastic modulus increasing by more than 16.5%.However,the existence of large second phases and wideδ′-PFZs in Li-containing alloys is detrimental to their ductility;as a result,their elongation is much lower than that of the base alloy.

关键词： Al-Mg-Si alloy Li addition Microstructure Aging behavior Mechanical properties Secondary ion mass spectrometer

Three-dimensional Model Analysis of Electric Field Excited by Multi-circuit Intersecting Overhead Transmission Lines

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高电压技术 2013年第8期39卷 2006-2013页

作者： xiao Dongping LEI hui ZHANG Zhanlong HE Wei State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing 400030 China

This work is carried out to predict the special distribution of electric field induced by multi-circuit intersecting overhead high-voltage (HV) transmission lines (TLs) within a large range without any expensive and time-consuming computation. The two main parts of the presented methodology are 1) setting up a three-dimensional (3D) model to calculate the electric field based on combining ca- tenary equations with charge simulation method and 2) calculating the hybrid electric field excited by multi-circuit intersecting TLs using coordinate transformation and superposition technique. Examples of different TLs configurations, including a 220 kV single-circuit hori- zontally configured TLs, a 500 kV single-circuit triangularly configured TLs and a combination of the 220 kV TLs and the 550 kV TLs, are illustrated to verify the validity of this methodology. A more complicatal configurations, including a 500 kV double-circuit TLs and two 220 kV single-circuit horizontally configured TLs, are also calculated. Conclusions were drawn from the simulation: 1) The presented 3D model outperforms 2D models in describing the electric field distribution generated by practical HV TLs with sag and span. 2) Coordinate trans- formation and superposition technique considerably simplify the electric field computation for multi-circuit TLs configurations, which makes it possible to deal with complex engineering problems. 3) The electric field in the area covered by multiple intersecting overhead TLs is distorted and the hybrid electric field strength in some partial region increases so sharply that it might exceed the admissible value. 4) The configuration parameters of the TLs and the spatial configuration of multi-circuit TLs, for instance, the height of TLs, the length of span and the intersection angle of multiple circuits, influence the strength and the distribution of hybrid electric field. The influence regularities sum- marized in this paper can be referred by future TL designs t

关键词：架空输电线路电场分布模型分析相交三维多路激发 220千伏

Cross-sectional survey following a longitudinal study on mental health and insomnia of people with sporadic COVID-19

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World Journal of Psychiatry 2022年第8期12卷 1076-1087页

作者： xiao-Jun Li Tian-Ze guo Yan Xie Yan-Ping Bao Jia-Yue Si Zhe Li Yi-Ting Xiong hui Li Su-Xia Li Lin Lu Xue-Qin Wang Department of Psychiatry Peking University International HospitalBeijing 102206China Department of Bioengineering University of California San DiegoSan DiegoCA 92093United States Department of Psychology Peking University International HospitalBeijing 102206China Department of Epidemiology National Institute on Drug Dependence and Beijing Key laboratory of Drug DependencePeking UniversityBeijing 100191China University of California Davis DavisCA 95616United States Department of History University College LondonLondon WC1E 6BTUnited Kingdom Department of Psychiatry Peking University Sixth HospitalPeking University Institute of Mental HealthNHC Key Laboratory of Mental Health(Peking University)National Clinical Research Center for Mental Disorders(Peking University Sixth Hospital)Peking UniversityBeijing 100191China Department of Clinical Pharmacology National Institute on Drug Dependence and Beijing Key Laboratory of Drug DependencePeking UniversityBeijing 100191China Peking-Tsinghua Centre for Life Sciences and Peking University-International Development Group/McGovern Institute for Brain Research Peking UniversityBeijing 100091China

BACKGROUNDIn the post-pandemic era, the emergence of sporadic cases of coronavirus disease 2019 (COVID-19) and the scale of the pandemic are unpredictable. Therefore, the impact ofsporadic cases of COVID-19 and isolation measures on mental health and sleep in different groupsof people need to be *** clarify the severity of psychological problems and insomnia of staff and community residentsaround a hospital with sporadic cases of COVID-19, and their relationship with quarantinelocation and long-term *** cross-sectional survey was conducted on community residents and medical staff. Many of thesemedical staff had been subjected to different places of quarantine. Community residents did notexperience quarantine. Hospital anxiety and depression scale (HADS), acute stress disorder scale(ASDS) and insomnia severity index (ISI) were used to evaluate anxiety and depression, acutestress disorder symptoms, and the severity of insomnia. Additionally, we conducted a 1-yearfollow-up study on medical staff, with related scales measurement immediately after and one yearafter the 2-wk quarantine *** included 406 medical staff and 226 community residents. The total scores of ISI and subscale inHADS of community residents were significantly higher than that of medical staff. Furtheranalysis of medical staff who experienced quarantine showed that 134 were quarantined in hotels,70 in hospitals and 48 at home. Among all subjects, the proportions of HADS, ASDS and ISI scoresabove normal cutoff value were 51.94%, 19.17% and 31.11%, respectively. Multivariable logisticregression analysis found that subjects with higher total ASDS scores had a greater risk to developanxiety and depression. The total ISI score for medical staff in hotel quarantine was significantlyhigher than those in home quarantine. Total 199 doctors and nurses who completed the 1-yearfollow-up study. Compared with baseline, HADS and ASDS scores decreased significantly oneyear after the

关键词： COVID-19 Depression Anxiety Insomnia Quarantine

Large magnetic entropy change in weberite-type oxides Gd_(3)MO_(7)(M=Nb,Sb,and Ta)

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Science China(Physics,Mechanics & Astronomy) 2022年第4期65卷 86-94页

作者： Ziyu Yang Shijun Qin Xubin Ye Zhehong Liu Yujie guo Hongzhi Cui Jun-Yi Ge hui Li Youwen Long Yu-Jia Zeng College of Civil and Transportation Engineering College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China Materials Genome Institute Shanghai UniversityShanghai 200444China College of Engineering Physics Shenzhen Technology UniversityShenzhen 518118China

In the present work,the structure,magnetic properties,and cryogenic magnetocaloric effect of weberite-type oxides Gd_(3)MO_(7)(M=Nb,Sb,and Ta)are reported through powder X-ray diffraction,bulk susceptibility,and heat capacity measurements,as well as scaling law analysis and a mean-field approach.A remarkably large isothermal magnetic entropy change of 354.0 m J K^(-1)cm^(-3)is observed for Gd_(3)SbO_(7)under an external field of 9 T at 2.0 *** relative cooling power is estimated to be 618.9 J kg^(-1)(4.8 J cm^(-3))for an applied field of 8.9 T,with the largest adiabatic temperature change being 22.4 K at 6.3 *** magnetocaloric performance of these oxides is quite impressive when compared with the benchmark magnetic refrigerant,gadolinium gallium garnet(Gd_(3)Ga_(5)O_(12),GGG).Therefore,Gd_(3)MO_(7)(M=Nb,Sb,and Ta)are promising alternatives for cryogenic cooling techniques,especially for the magnetic liquefaction of helium.

关键词： magnetocaloric effect antiferromagnetism oxides cryogenic rare earths

Cooperative Detection Method for DDoS Attacks Based on Blockchain

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Computer Systems Science & Engineering 2022年第10期43卷 103-117页

作者： Jieren Cheng Xinzhi Yao hui Li Hao Lu Naixue Xiong Ping Luo Le Liu Hao guo Wen Feng Hainan University Haikou570228China Hainan Blockchain Technology Engineering Research Center Haikou570228China Hainan Huochain Tech Company Limited Haikou570100China Research Office of Information Technology Air Force Early Warning AcademyWuhan430019China Department of Mathematics and Computer Science Northeastern State UniversityTahlequah74464USA

Distributed Denial of Service(DDoS)attacks is always one of the major problems for service *** blockchain to detect DDoS attacks is one of the current popular ***,the problems of high time overhead and cost exist in the most of the blockchain methods for detecting DDoS *** paper proposes a blockchain-based collaborative detection method for DDoS ***,the trained DDoS attack detection model is encrypted by the Intel Software Guard Extensions(SGX),which provides high security for uploading the DDoS attack detection model to the ***,the service provider uploads the encrypted model to Inter Planetary File System(IPFS)and then a corresponding Content-ID(CID)is generated by IPFS which greatly saves the cost of uploading encrypted models to the *** addition,due to the small amount of model data,the time cost of uploading the DDoS attack detection model is greatly ***,through the blockchain and smart contracts,the CID is distributed to other service providers,who can use the CID to download the corresponding DDoS attack detection model from *** provides a decentralized,trusted and tamper-proof environment for service ***,smart contracts and IPFS greatly improve the distribution efficiency of the model,while the distribution of CID greatly improves the efficiency of the transmission on the *** this way,the purpose of collaborative detection can be achieved,and the time cost of transmission on blockchain and IPFS can be considerably *** designed a blockchain-based DDoS attack collaborative detection framework to improve the data transmission efficiency on the blockchain,and use IPFS to greatly reduce the cost of the distribution *** the experiment,compared with most blockchain-based method for DDoS attack detection,the proposed model using blockchain distribution shows the advantages of low cost and *** remote authentication mechanism of Intel

关键词： Blockchain smart contract IPFS DDoS attack

Study on the clogging mechanism of punching screen in sand control by the punching structure parameters

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Petroleum Science 2024年第1期21卷 609-620页

作者： Fu-Cheng Deng Fu-Lin Gui Bai-Tao Fan Lei Wen Sheng-Hong Chen Ning Gong Yun-Chen xiao Zhi-hui Xu Yangtze University Jingzhou434023HubeiChina CNOOC Research Institute Ltd. Beijing100028China CNOOC Ener Tech-Drilling&Production Co. Tianjin300457China Tianjin Branch of CNOOC Ltd. Tianjin300459China

As an independent sand control unit or a common protective shell of a high-quality screen,the punching screen is the outermost sand retaining unit of the sand control pipe which is used in geothermal well or oil and gas ***,most screens only consider the influence of the internal sand retaining medium parameters in the sand control performance design while ignoring the influence of the plugging of the punching screen on the overall sand retaining performance of the *** explore the clogging mechanism of the punching screen,this paper established the clogging mechanism calculation model of a single punching screen sand control unit by using the computational fluid mechanics-discrete element method(CFD-DEM)combined *** to the combined motion of particles and fluids,the influence of the internal flow state on particle motion and accumulation was *** results showed that(1)the clogging process of the punching sand control unit is divided into three stages:initial clogging,aggravation of clogging and stability of *** the initial stage of blockage,coarse particles form a loose bridge structure,and blockage often occurs preferentially at the streamline gathering place below chamfering inside the sand control *** the stage of blockage intensification,the particle mass develops into a relatively complete sand bridge,which develops from both ends of the opening to the center of the *** the stable plugging stage,the sand deposits show a“fan shape”and form a“V-shaped”gully inside the punching slot element.(2)Under a certain reservoir particle-size distribution,The slit length and opening height have a large influence on the permeability and blockage rate,while the slit width size has little influence on the permeability and blockage *** microscopic clogging mechanism and its law of the punching screen prevention unit are proposed in this study,which has some field guidance significance for the design of punching screen

关键词： Punching screen Plugging CFD-DEM Size parameter Sand control

Role of academic self-efficacy in the relationship between self-directed learning readiness and problem-solving ability among nursing students

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Frontiers of Nursing 2018年第1期5卷 75-81页

作者： xiao-Hong Zhang Li-Na Meng hui-hui Liu Ru-Zhen Luo Chun-Mei Zhang Pei-Pei Zhang Yan-hui Liu Tianjin University of Traditional Chinese Medicine Tianjin 300193China Inspection Department Tianjin Childrens HospitalTianjin 300134China

Objective: Problem-solving should be a fundamental component of nursing education because It is a core ability for professional nurses. For more effective learning, nursing students must understand the relationship between self-directed learning readiness and problem-solving ability. The aim of this study was to investigate the relationships among self-directed learning readiness, problemsolving ability, and academic self-efficacy among undergraduate nursing ***: From November to December 2016, research was conducted among 500 nursing undergraduate students in Tianjin, China,using a self-directed learning readiness scale, an academic self-efficacy scale, a questionnaire related to problem-solving, and selfdesigned demographics. The response rate was 85.8%.Results: For Chinese nursing students, self-directed learning readiness and academic self-efficacy reached a medium-to-high level,while problem-solving abilities were at a low level. There were significant positive correlations among the students' self-directed learning readiness, academic self-efficacy, and problem-solving ability. Furthermore, academic self-efficacy demonstrated a mediating effect on the relationship between the students' self-directed learning readiness and problem-solving ***: To enhance students' problem-solving ability, nursing educators should pay more attention to the positive impact of self-directed learning readiness and self-efficacy in nursing students' education.

关键词： self-directed learning readiness problem-solving ability academic self-efficacy nursing undergraduates nursing students cross-sectional survey

Solving Surface Deformation of Radio Telescope Antenna by Artificial Neural Network

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Research in Astronomy and Astrophysics 2022年第3期22卷 194-204页

作者： Bo-Yang Wang Qian Ye Li Fu guo-Xiang Meng Jin-Qing Wang Qing-hui Liu Zhi-Qiang Shen School of Mechanical Engineering Shanghai Jiaotong UniversityShanghai 200240China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

Recent investigations have derived the relation between the near-field plane amplitude and the surface deformation of reflector antenna,namely deformation-amplitude equation(DAE),which could be used as a mathematical foundation of antenna surface measurement if an effective numerical algorithm is *** algorithms are hard to work directly due to the complex mathematical *** paper presents a local approximation algorithm based on artificial neural network to solve *** length factor method is used to construct a trial solution for the deformation,which ensures the final solution always satisfies the boundary *** improve the algorithm efficiency,Adam optimizer is employed to train the network *** the application of the data normalization method proposed in this paper and a step-based learning rate,a further optimized loss function could be converged *** algorithm proposed in this paper could effectively solve partial differential equations without boundary conditions such as DAE,which at the same time contains the first-order and the second-order partial derivatives,and constant *** results show that compared with the original algorithm by Fast Fourier transform,this algorithm is more stable and accurate,which is significant for the antenna measurement method based on DAE.

关键词： methods:numerical telescopes waves scattering