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Recent progress in ZnO-based heterojunction ultraviolet light-emitting devices

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Chinese Science Bulletin 2014年第12期59卷 1219-1227页

作者： Yichun Liu Haiyang Xu Chunyang Liu weizhen Liu Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education Northeast Normal University

Wide bandgap(3.37 eV)and high excitonbinding energy of ZnO(60 meV)make it a promising candidate for ultraviolet light-emitting diodes(LEDs)and low-threshold lasing diodes(LDs).However,the difficulty in producing stable and reproducible high-quality p-type ZnO has hindered the development of ZnO p–n homojunction *** alternative strategy for achieving ZnO electroluminescence is to fabricate heterojunction devices by employing other available p-type materials(such as p-GaN)or building new device *** this article,we will briefly review the recent progress in ZnO LEDs/LDs based on p–n heterostructures and metal–insulatorsemiconductor *** methods to improve device efficiency are also introduced in detail,including the introduction of Ag localized surface plasmons and single-crystalline nanowires into ZnO LEDs/LDs.

关键词：紫外发光二极管异质结器件 ZnO 光发射器件表面等离子体激元异质结构氧化锌激光二极管

Response of monsoon vari-ability in Himalayas to global warming

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Chinese Science Bulletin 2002年第21期47卷 1842-1845页

作者： DUAN Keqin YAO Tandong PU Jianchen SUN weizhen Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of SciencesLanzhou 730000China

Reconstructed annual net accumulation from the Dasuopu ice core recovered in Himalayas, with a good correlation to Indian monsoon, reflects a major precipitation trend in central Himalayas. The Dasuopu accumulation (DSP An) also shows a strong correlation to the Northern hemispheric temperature. Generally, as the Northern hemispheric temperature increases by 0.1 K, the accumulation decreases by about 90 mm and vise versa. Under the condition of global warming, especially since 1920, the Northern hemispheric mean temperature has increased by about 0.5 K, whereas accumulation in Dasuopu ice core has decreased by about 450 mm. According to the relationship between accumulation and temperature, a scenario prediction of monsoon rainfall in central Himalayas is made.

关键词： Dasuopu ice core accumulation global warming.

PerfMon: Measuring Application-Level Performance in a Large-Scale Campus Wireless Network

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China Communications 2023年第3期20卷 316-335页

作者： weizhen Dang Tao Yu Haibo Wang Jing’An Xue Fenghua Li Jilong Wang Institute for Network Sciences and Cyberspace Tsinghua UniversityBeijing 100084China Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology(BNRist) Beijing 100084China Huawei Technologies Beijing 100085China Zhongguancun Laboratory Beijing 100094China

WiFi has become one of the most popular ways to access the ***,in large-scale campus wireless networks,it is challenging for network administrators to provide optimized access quality without knowledge on fine-grained traffic characteristics and real network *** this paper,we implement PerfMon,a network performance measurement and diagnosis system,which integrates collected multi-source datasets and analysis *** on PerfMon,we first conduct a comprehensive measurement on application-level traffic patterns and behaviors from multiple dimensions in the wireless network of T university(TWLAN),which is one of the largest campus wireless *** we systematically study the application-level network *** observe that the application-level traffic behaviors and performance vary greatly across different locations and device *** performance is far from satisfactory in some *** diagnose these problems,we distinguish locations and device types,and further locate the most crucial factors that affect the *** results of case studies show that the influential factors can effectively characterize performance changes and explain for performance degradation.

关键词： WiFi traffic patterns network manage-ment performance measurement network diagnosis

Experiments and kinetic modeling of the sorbitol dehydration to isosorbide catalyzed by sulfuric acid under conditions of non-constant volume

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Chinese Journal of Chemical Engineering 2024年第9期73卷 281-289页

作者： Dechang Cheng Zhihong Ma Ziyang Liu Xiaohui Liu Tao Liu weizhen Sun Ling Zhao State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China Shanghai Key Laboratory of Functional Materials Chemistry Research Institute of Industrial CatalysisSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Isosorbide is a novel bio-based material derived as a secondary dehydration product of *** work focuses on the kinetics of sulfuric acid-catalyzed dehydration of sorbitol under conditions of nonconstant ***,the effects of stirring rate,catalyst dosage,reaction temperature,and reaction time on the dehydration reaction of sorbitol were *** yield of isosorbide up to 77.13%was obtained after 1.5 h of reaction time under conditions of 2 kPa,1.0%(mass)catalyst dosage,and 413.15 *** on the sorbitol dehydration reaction mechanism and a simplified reaction network,a kinetic model was developed in this work.A good agreement was accomplished between kinetic modeling and experiments between 393.15 and 423.15 *** fitting results indicate that side reactions with higher activation energies are more affected by reaction temperatures,and the main side reaction that influences the selectivity of isosorbide is the oligomerization reaction among the primary dehydration products of *** model fitting of the catalyst amounts effect shows that the effective concentration of sulfuric acid would be reduced with the increase of dosage due to the molecular agglomeration ***,the kinetic experiments and modeling results obtained in this work will be helpful to the design and optimization of the industrial sorbitol dehydration process.

关键词： Isosorbide Sorbitol dehydration Non-constant volume Kinetic modeling

Phenylboronic acid-modified hollow silica nanoparticles for dual-responsive delivery of doxorubicin for targeted tumor therapy

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Regenerative Biomaterials 2017年第2期4卷 111-124页

作者： Ling Huang Qingfeng Zhang Liangliang Dai Xinkun Shen weizhen Chen Kaiyong Cai Key Laboratory of Biorheological Science and Technology Ministry of Education College of BioengineeringChongqing UniversityChongqing 400044P.R.China

This work reports a multifunctional nanocarrier based on hollow mesoporous silica nanoparticles(HMSNs)for targeting tumor ***(DOX)was loaded into HMSNs and blocked with cytochrome C conjugated lactobionic acid(CytC–LA)via redox-cleavable disulfide bonds and pH-disassociation boronate ester bonds as intermediate *** CytC–LA was used both as sealing agent and targeting motif.A series of characterizations demonstrated the successful construction of the drug delivery *** system demonstrated pH and redox dual-responsive drug release behavior in *** DOX loading HMSNs system displayed a good biocompatibility,which could be specifically endocytosed by hepG2 cells and led to high cytotoxicity against tumor cells by inducing cell *** vivo data(tumor volume,tumor weight,terminal deoxynucleotidyl transferase dUTP nick end labeling and hematoxylin and eosin staining)proved that the system could deliver DOX to tumor site with high efficiency and inhibit tumor growth with minimal toxic side effect.

关键词： hollow mesoporous silica nanoparticles dual-response drug delivery targeted tumor therapy in vivo

Magnetism of NaYbS_(2):From finite temperatures to ground state

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Science China(Physics,Mechanics & Astronomy) 2024年第10期67卷 92-104页

作者： weizhen Zhuo Zheng Zhang Mingtai Xie Anmin Zhang Jianting Ji Feng Jin Qingming Zhang School of Physical Science and Technology Lanzhou UniversityLanzhou 730000China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Rare-earth chalcogenide compounds ARECh_(2)(A=alkali or monovalent metal,RE=rare earth,Ch=O,S,Se,Te)are a large family of quantum spin liquid(QSL)candidate ***2is a representative member of the *** key issues on NaYbS_(2),particularly how to determine the highly anisotropic spin Hamiltonian and describe the magnetism at finite temperatures and the ground state,remain to be *** this paper,we conducted an in-depth and comprehensive study on the magnetism of NaYbS_(2) from finite temperatures to the ground ***,we successfully detected three crystalline electric field(CEF)excitation energy levels using low-temperature Raman scattering *** them with the CEF theory and magnetization data,we worked out the CEF parameters,CEF energy levels,and CEF *** further determined a characteristic temperature of~40 K,above which the magnetism is dominated by CEF excitations while below which the spinexchange interactions play a main *** characteristic temperature has been confirmed by the temperature-dependent electron spin resonance(ESR)***-temperature ESR experiments on the dilute magnetic doped crystal of NaYb_(0.1)Lu_(0.9)S_(2) further helped us to determine the accurate ***,we quantitatively obtained the spin-exchange interactions in the spin Hamiltonian by consistently simulating the magnetization and specific heat ***,the above studies allow us to explore the ground state magnetism of NaYbS_(2) by using the density matrix renormalization *** combined numerical calculations and experimental results to demonstrate that the ground state of NaYbS_(2) is a Dirac-like QSL.

关键词： rare-earth chalcogenide anisotropic spin Hamiltonian quantum spin liquid

Singlet oxygen-dominated peroxymonosulfate activation by layered crednerite for organic pollutants degradation in high salinity wastewater

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Journal of Environmental Sciences 2024年第1期135卷 86-96页

作者： Chengji Sui Zixuan Nie Huan Liu Grzegorz Boczkaj weizhen Liu Lingshuai Kong Jinhua Zhan Key Laboratory for Colloid&Interface Chemistry of Education Ministry Department of ChemistryShandong UniversityJinan 250100China School of Environment and Energy Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and RecyclingSouth China University of TechnologyGuangzhou 510006China Gdansk University of Technology Faculty of Civil and Environmental EngineeringDepartment of Sanitary EngineeringG.Narutowicza St.11/1280-233 GdanskPoland EkoTech Center Gdansk University of TechnologyG.Narutowicza St.11/1280-233 GdanskPoland

Advanced oxidation processes have been widely studied for organic pollutants treatment in water,but the degradation performance of radical-dominated pathway was severely inhibited by the side reactions between the anions and radicals,especially in high salinity ***,a singlet oxygen(^(1)O_(2))-dominated non-radical process was developed for organic pollutants degradation in high salinity wastewater,with layered crednerite(CuMnO_(2))as catalysts and peroxymonosulfate(PMS)as *** on the experiments and density functional theory calculations,^(1)O_(2)was the dominating reactive species and the constructed Cu-O-Mn with electron-deficient Mn captured electron from PMS promoting the generation of^(1)O_(2).The rapid degradation of bisphenol A(BPA)was achieved by CuMnO_(2)/PMS system,which was 5-fold and 21-fold higher than that in Mn_(2)O_(3)/PMS system and Cu_(2)O/PMS *** CuMnO_(2)/PMS system shown prominent BPA removal performance under high salinity conditions,prominent PMS utilization efficiency,outstanding total organic carbon removal rate,wide range of applicable pH and good *** work unveiled that the^(1)O_(2)-dominated non-radical process of CuMnO_(2)/PMS system overcame the inhibitory effect of anions in high salinity conditions,which provided a promising technique to remove organic pollutants from high saline wastewater.

关键词： Singlet oxygen Non-radical process High salinity Mixed metal oxides Wastewater treatment

Clustering Analysis of Black-start Decision-making with a Large Group of Decision-makers

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电力系统自动化 2012年第8期36卷 154-160页

作者： Liu, Weijia Lin, Zhenzhi Wen, Fushuan Xue, Yusheng Dai, Yan Sun, weizhen Wang, Chao Zhejiang University Hangzhou 310027 China State Grid Electric Power Research Institute Nanjing 210003 China Zhejiang Electric Power Dispatch and Communication Center Hangzhou 310007 China

The optimization of black-start decision-making plays an important role in the rapid restoration of a power system after a major failure/*** the introduction of the concept of smart grids and the development of real-time communication networks,the black-start decision-makers are no longer limited to only one or a few power system experts such as dispatchers,but rather a large group of professional people in *** overall behaviors of a large decision-making group of decision-makers/experts are more complicated and ***,the existing methods for black-start decision-making cannot handle the situations with a large group of *** this background,a clustering algorithm is presented to optimize the black-start decision-making problem with a large group of *** decision-making preferences are obtained by clustering analysis,and the final black-start decision-making results are achieved by combining the weights of black-start indexes and the preferences of the decision-making *** effectiveness of the proposed method is validated by a practical *** work extends the black-start decision-making problem to situations with a large group of decision-makers.

关键词：决策者聚类分析黑启动大集实时通信网络决策问题电力系统电源系统

Polar solvent induced in-situ self-assembly and oxygen vacancies on Bi_(2)MoO_(6)for enhanced photocatalytic degradation of tetracycline

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Nano Research 2024年第6期17卷 4951-4960页

作者： Fangyan Liu Dongyue Su weizhen Liu Baiquan Liu Chuan Liu Hong Wang Mengye Wang State Key Laboratory of Optoelectronic Materials and Technologies Guangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologySun Yat-Sen UniversityGuangzhou 510275China School of Materials Sun Yat-Sen UniversityShenzhen 518107China School of Environment and Energy Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and RecyclingSouth China University of TechnologyGuangzhou 510006China

It has been proved to be an effective route to efficiently ameliorate photocatalytic performance of catalysts via designing three-dimensional(3D)hierarchical nanostructures and constructing oxygen vacancies(VOs).However,controlling the self-assembly of organization into 3D hierarchical nanostructures while introducing VOs in photocatalysts remains a ***,we reported an ethylene glycol(EG)mediated approach to craft 3D hydrangea-structure Bi_(2)MoO_(6)with VOs for efficient photocatalytic degradation of *** manipulating the EG concentration during the fabrication process,the influence of EG concentration on the Bi_(2)MoO_(6)structure was systematically *** could promote the self-assembly of Bi_(2)MoO_(6)nanosheets to form a 3D hierarchical *** with 2D nanoplates,3D hierarchical architecture enhanced the surface area and the amount of active sites of Bi_(2)MoO_(6).In addition,the reduction effect of EG on metallic oxide enabled the generation of VOs in Bi_(2)MoO_(6).The VOs adjusted the electronic structure of Bi_(2)MoO_(6),which not only enhanced the light harvesting,but also facilitated the simultaneous utilization of photo-induced electrons and holes to form reactive oxygen species(·O2−and·OH)for the efficient tetracycline decomposition.3D Bi_(2)MoO_(6)hydrangea with VOs achieved a 79.4%removal efficiency of tetracycline after 75 *** work provides a simple yet robust EG-mediated strategy,which not only promotes the self-assembly of nano-catalysts into 3D hierarchical architectures,but also crafts tunable VOs for highly efficient photocatalysis.

关键词： three-dimensional(3D)hierarchical nanostructures tunable oxygen vacancies ethylene glycol(EG)-mediated strategy bismuth molybdate photocatalytic degradation tetracycline