检索结果-南通市图书馆

Electrostatic self-assembly of 2D/2D CoWO_(4)/g-C_(3)N_(4)p-n heterojunction for improved photocatalytic hydrogen evolution:Built-in electric field modulated charge separation and mechanism unveiling

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2022年第8期15卷 6987-6998页

作者： Haiyang Wang Ranran Niu Jianhui liu Sheng Guo Yongpeng Yang zhongyi liu Jun Li Henan Institute of Advanced Technology College of ChemistryZhengzhou UniversityZhengzhou 450052China School of Chemistry and Environmental Engineering Wuhan Institute of TechnologyWuhan 430205China

Two-dimensional(2D)semiconductor heterojunctions are considered as an effective strategy to achieve fast separation of photoinduced carriers.Herein,a novel CoWO_(4)/g-C_(3)N_(4)(CWO/CN)p–n junction was synthesized using an electrostatic selfassembly method.The constructed 2D/2D p–n heterostructure had a rich hetero-interface,increased charge density,and fast separation efficiency of photoinduced carriers.The in-situ Kelvin probe force microscopy confirmed that the separation pathway of photoinduced carriers through the interface obeyed an II-scheme charge transfer mechanism.Experimental results and density functional theory calculations indicated the differences of work function between CWO and CN induced the generation of built-in electric field,ensuring an efficient separation and transfer process of photoinduced carriers.Under the optimized conditions,the CWO/CN heterojunction displayed enhanced photocatalytic H_(2)generation activity under full spectrum and visible lights irradiation,respectively.Our study provides a novel approach to design 2D/2D hetero-structured photocatalysts based on p–n type semiconductor for photocatalytic H_(2)generation.

关键词： p-n junction interfacial charge transfer two-dimensional/two-dimensional photocatalytic H_(2)generation CoWO_(4)/g-C_(3)N_(4)heterojunction

Highly efficient visible/near-infrared light photocatalytic degradation of antibiotic wastewater over 3D yolk-shell ZnFe_(2)O_(4)supported 0D carbon dots with up-conversion property

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2022年第9期35卷 213-223页

作者： Weilong Shi Jie Gao Haoran Sun zhongyi liu Feng Guo Lijing Wang College of Chemistry Zhengzhou UniversityZhengzhou 450001China School of Life Sciences Northwestern Polytechnical UniversityXi’an 710072China School of Material Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Henan Engineering Center of New Energy Battery Materials Henan D&A Engineering Center of Advanced Battery MaterialsCollege of Chemistry and Chemical EngineeringInstitute of Architectural EngineeringShangqiu Normal UniversityShangqiu 476000China

The development of effective visible and near-infrared photocatalysts is highly promising in the current field of photocatalysis.Herein,carbon dots/ZnFe_(2)O_(4)(CDs/ZFO)with coating zero dimensional(0D)CDs on the surface of three dimensional(3D)yolk-shell ZFO spheres was designed and synthesized via a selftemplated solvothermal method.The as-prepared CDs/ZFO composites displayed outstanding visible and near-infrared photocatalytic degradation activity of tetracycline(TC),and the optimal 3%CDs/ZFO sample with loading 3%(mass)CDs displayed the highest photocatalytic TC degradation ability under visible light(79.5%within 120 min)and near-infrared light(41%within 120 min).The enhancement of photocatalytic activity for CDs/ZFO composite is mainly ascribed to the fact that 0D/3D yolk-shell CDs/ZFO structure not only effectively reflect the incident light to increase the utilization efficiency of solar light,but also utilize the up-conversion photoluminescence and electronic conductivity properties of CDs to broaden sunlight absorption range and promote separation and transfer of electron-hole pairs.

关键词： Carbon dots ZnFe_(2)O_(4) York-shell Near-infrared Photocatalytic

Recent Development in Defects Engineered Photocatalysts:An Overview of the Experimental and Theoretical Strategies

在线全文

学校读者我要写书评

暂无评论

Energy & Environmental Materials 2022年第1期5卷 68-114页

作者： Zaiba Zafar Shasha Yi Jinpeng Li Chuanqi Li Yongfa Zhu Amir Zada Weijing Yao zhongyi liu Xinzheng Yue College of Chemistry School of Material Science and EngineeringZhengzhou UniversityZhengzhou 450001China Department of Chemistry Tsinghua UniversityBeijing 100084China Department of Chemistry Abdul Wali Khan University MardanMardan 23200Pakistan

Recently,defect architectured photocatalysis is proved to be the most versatile choice for high solar to chemical energy conversion processes.Defect engineering strategies are of great demand to effectively tune the electronic microstructure and surface morphologies of semiconductors to boost charge carrier concentration and extend light harvesting capability.This review provides a comprehensive insight to various kinds of defects along with their synthesis procedures and controlling mechanism to uplift photocatalytic activity.In addition,the contribution made by defects and material optimization techniques toward electronic band structure of the photocatalyst,the optimal concentration of defects,the key adsorption processes,charge distribution,and transfer dynamics have been explained in detail.Further,to clarify the relationship between photocatalytic activity and defect states in real,a comprehensive outlook to the versatile photocatalytic applications has been presented to highlight current challenges and future applications.Defect engineering therefore stands as the next step toward advancement in the design and configuration of modern photocatalysts for high efficiency photocatalysis.

关键词： defect engineering electronic structure photocatalysis vacancies

我国托育服务供给体系的建构:基于“公共/私人”分析框架的思考

在线全文

学校读者我要写书评

暂无评论

甘肃社会科学 2024年第2期 109-117页

作者：刘中一中国人口与发展研究中心人口研究部北京100081

不同历史时期、不同的国家地区,公共托育与私人托育供给间有着不同组合,由此形成三种特色鲜明的托育服务供给体系类型:以保姆和祖辈托育等个体化托育为主导的私人托育服务供给体系;以托儿所、托婴中心等机构化托育为主导的公共托育服务... 详细信息

不同历史时期、不同的国家地区,公共托育与私人托育供给间有着不同组合,由此形成三种特色鲜明的托育服务供给体系类型:以保姆和祖辈托育等个体化托育为主导的私人托育服务供给体系;以托儿所、托婴中心等机构化托育为主导的公共托育服务供给体系;以公共托育与私人托育混合发展的多元托育服务供给体系。从供给影响需求的角度看,公共托育与私人托育供给都有自己的适用性和局限性。从家庭托育、家庭式托育到家庭托育点,不仅意味着托育服务供给形式的变动,也标志着社会政策重心在私人托育和公共托育供给安排上的调整。家庭式托育和家庭托育点一定程度上实现了公共托育与私人托育供给的协同。长远来看,我国普惠托育服务供给体系的建构路径一定不是公共托育与私人托育“二选一”,而是要实现公共托育与私人托育的共同发展。为此,第一,需要重新思考公共托育与私人托育的关系,需要对家庭托育等私人托育在托育服务供给体系中的地位和作用进行科学定位;第二,需要对托育服务供给体系中私人托育发展进行资源支持和政策扶植;第三,需要辩证地对待公共托育与私人托育各自的特点,反对过分夸大任何一种托育服务供给的地位和作用。

关键词：托育服务公共托育私人托育供给体系普惠托育

SnS_2@C Hollow Nanospheres with Robust Structural Stability as High?Performance Anodes for Sodium Ion Batteries

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2019年第1期11卷 241-249页

作者： Shuaihui Li Zhipeng Zhao Chuanqi Li zhongyi liu Dan Li College of Chemistry and Molecular Engineering Zhengzhou University Henan Institute of Advanced Technology Zhengzhou University

Constructing unique and highly stable structures with plenty of electroactive sites in sodium storage materials is a key factor for achieving improved electrochemical properties through favorable sodium ion di usion kinetics. An SnS_2@carbon hollow nanospheres(SnS_2@C) has been designed and fabricated via a facile solvothermal route, followed by an annealing treatment. The SnS_2@C hybrid possesses an ideal hollow structure, rich active sites, a large electrode/electrolyte interface, a shortened ion transport pathway, and, importantly, a bu er space for volume change, generated from the repeated insertion/extraction of sodium ions. These merits lead to the significant reinforcement of structural integrity during electrochemical reactions and the improvement in sodium storage properties, with a high specific reversible capacity of 626.8 mAh g^(-1) after 200 cycles at a current density of 0.2 A g^(-1) and superior high-rate performance(304.4 mAh g^(-1) at 5 A g^(-1)).

关键词： SnS2@C Hollow nanospheres Anode materials Sodium ion batteries

融合BERT多层次特征的短视频网络舆情情感分析研究

在线全文

学校读者我要写书评

暂无评论

计算机科学与探索 2024年第4期18卷 1010-1020页

作者：韩坤潘宏鹏刘忠轶中国人民公安大学公安管理学院北京100038

自媒体时代与网络社交软件的广泛普及,导致短视频平台极易成为舆情事件起源和发酵的“孵化器”。分析短视频平台中的舆情评论信息,对于舆情事件的预警、处置和引导具有重要意义。鉴于此,结合BERT与TextCNN模型,提出一种融合BERT多层次... 详细信息

自媒体时代与网络社交软件的广泛普及,导致短视频平台极易成为舆情事件起源和发酵的“孵化器”。分析短视频平台中的舆情评论信息,对于舆情事件的预警、处置和引导具有重要意义。鉴于此,结合BERT与TextCNN模型,提出一种融合BERT多层次特征的文本分类模型(BERT-MLFF-TextCNN),并对抖音短视频平台中的相关评论文本数据进行情感分析。首先,利用BERT预训练模型对输入文本进行编码。其次,提取各编码层中的语义特征向量进行融合。然后,融入自注意力机制突出其关键特征,从而实现特征的有效利用。最后,将所得特征序列输入TextCNN模型中进行分类。实验结果表明,与BERT-TextCNN、GloVe-TextCNN和Word2vec-TextCNN模型相比,BERT-MLFF-TextCNN模型表现更优,F1值达到了0.977。通过该模型能够有效识别短视频平台舆情的情感倾向,在此基础上利用TextRank算法进行主题挖掘,实现舆情评论情感极性的主题词可视化,为相关部门的舆情管控工作提供决策参考。

关键词：网络舆情情感分析主题可视化 BERT

在线全文

学校读者我要写书评

暂无评论

数字经济治理对公民安全感知的影响机理研究

工程管理科技前沿 2024年第3期43卷 90-96页

作者：潘宏鹏刘忠轶中国人民公安大学公安管理学院北京100038

数字经济治理对于推动区域数字经济发展、建设数字中国具有重要意义,已成为我国新发展阶段的重要课题。为深入探究数字经济治理与公民安全感知之间的“黑箱”机制,本文基于B市问卷调查数据,进行了一系列假设推演与实证分析。研究发现,... 详细信息

数字经济治理对于推动区域数字经济发展、建设数字中国具有重要意义,已成为我国新发展阶段的重要课题。为深入探究数字经济治理与公民安全感知之间的“黑箱”机制,本文基于B市问卷调查数据,进行了一系列假设推演与实证分析。研究发现,数字经济治理会显著正向预测公民安全感知;数字经济发展评价在数字经济治理对公民安全感知的正向预测中起部分中介作用,数据隐私安全可对上述中介产生调节效应;数字技术普及正向调节数字经济治理与公民安全感知之间的关系。本文研究结果可为我国数字经济治理工作提供一定的参考。

关键词：数字经济治理公民安全感知数字经济发展评价

Cooperative Multi-Agent Reinforcement Learning with Constraint-Reduced DCOP

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Beijing Institute of Technology 2017年第4期26卷 525-533页

作者： Yi Xie zhongyi liu Zhao liu Yijun Gu School of Information Technology and Cybersecurity People's Public Security University of China Beijing 100038 China School of Management People's Public Security University of China Beijing 100038 China School of Postgraduates People's Public Security University of China Beijing 100038 China

Cooperative multi-agent reinforcement learning（ MARL） is an important topic in the field of artificial intelligence,in which distributed constraint optimization（ DCOP） algorithms have been widely used to coordinate the actions of multiple agents. However,dense communication among agents affects the practicability of DCOP algorithms. In this paper,we propose a novel DCOP algorithm dealing with the previous DCOP algorithms＇ communication problem by reducing constraints.The contributions of this paper are primarily threefold：（1） It is proved that removing constraints can effectively reduce the communication burden of DCOP algorithms.（2） An criterion is provided to identify insignificant constraints whose elimination doesn＇t have a great impact on the performance of the whole system.（3） A constraint-reduced DCOP algorithm is proposed by adopting a variant of spectral clustering algorithm to detect and eliminate the insignificant constraints. Our algorithm reduces the communication burdern of the benchmark DCOP algorithm while keeping its overall performance unaffected. The performance of constraint-reduced DCOP algorithm is evaluated on four configurations of cooperative sensor networks. The effectiveness of communication reduction is also verified by comparisons between the constraint-reduced DCOP and the benchmark DCOP.

关键词： reinforcement learning cooperative multi-agent system distributed constraint optimization （DCOP） constraint-reduced DCOP

小餐饮商户接入食品安全溯源体系策略博弈研究

在线全文

学校读者我要写书评

暂无评论

复杂系统与复杂性科学 2024年第1期21卷 145-151页

作者：吕洋刘忠轶张振源刘溪溪中国人民公安大学公安管理学院北京100038 山东财经大学法学院济南250014

为探究影响小餐饮商户接入食品安全溯源体系的关键因素及食品监管部门和社会公众的行为选择,基于演化博弈理论,构建了小餐饮商户、食品监管部门以及社会公众三方之间的演化博弈模型。在有限理性的假设下,分析了不同参数对博弈三方策略... 详细信息

为探究影响小餐饮商户接入食品安全溯源体系的关键因素及食品监管部门和社会公众的行为选择,基于演化博弈理论,构建了小餐饮商户、食品监管部门以及社会公众三方之间的演化博弈模型。在有限理性的假设下,分析了不同参数对博弈三方策略选择的影响。研究结果表明:为进一步维护食品安全环境,促使小餐饮商户选择积极接入食品安全溯源体系,应建立科学合理的奖惩与补偿机制,调动社会公众参与监管的积极性,利用信息技术手段降低小餐饮商户成本,实现食品全链条质量安全监管。

关键词：食品安全溯源体系小餐饮商户演化博弈