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Facile synthesis of wormlike quantum dots-encapsulated nanoparticles and their controlled surface functionalization for effective bioapplications

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Nano Research 2016年第9期9卷 2531-2543页

作者： Yajuan Yang Yu Qi Min Zhu nana Zhao Fujian Xu State Key Laboratory of Chemical Resource Engineering College of Materials Science & EngineeringBeijing University of Chemical TechnologyBeijing 100029China Beijing Laboratory of Biomedical Materials Beijing University of Chemical TechnologyBeijing 100029China Key Laboratory of Carbon Fiber and Functional Polymers of Ministry of Education Beijing University of Chemical TechnologyBeijing 100029China Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems School of Materials Science & EngineeringBeijing Institute of TechnologyBeijing 100081China

Semiconductor quantum dots (QDs) are considered as ideal fluorescent probes owing to their intrinsic optical properties. It has been demonstrated that the size and shape of nanoparticles significantly influence their behaviors in biological systems. In particular, one-dimensional (1D) nanoparticles with larger aspect ratios are desirable for cellular uptake. Here, we explore a facile and green method to prepare novel 1D wormlike QDs@SiO2nanoparticles with controlled aspect ratios, wherein multiple QDs are arranged in the centerline of the nanoparticles. Then, an excellent cationic gene carrier, ethanolamine-functionalized poly(glycidyl methacrylate) (denoted by BUCT-PGEA), was in-situ produced via atom transfer radical polymerization on the surface of the QDs@SiO2nanoparticles to achieve stable surfaces (QDs@SiO2-PGEA) for effective bioapplications. We found that the wormlike QDs@SiO2-PGEA nanoparticles demonstrated much higher gene transfection performance than ordinary spherical counterparts. In addition, the wormlike nanoparticles with larger aspect ratio performed better than those with smaller ratio. Furthermore, the gene delivery processes including cell entry and plasmid DNA (pDNA) escape and transport were also tracked in real time by the QDs@SiO2-PGEA/pDNA complexes. This work realized the integration of efficient gene delivery and real-time imaging within one controlled 1D nanostructure. These constructs will likely provide useful information regarding the interaction of nanoparticles with biological systems. [Figure not available: see fulltext.] © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

关键词： quantum dots morphology poly(glycidyl methacrylate)(PGMA) gene delivery imaging

User scheduling for downlink FD-MIMO systems under Rician fading exploiting statistical CSI

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Science China(Information Sciences) 2018年第8期61卷 160-169页

作者： Xiao LI Tingting SUN nana QIN Shi JIN Xiqi GAO National Mobile Communications Research Laboratory Southeast University

In this paper, we consider the user scheduling algorithm for downlink full-dimension multipleinput multiple-output(FD-MIMO) system under Rician fading channels. We assume that two-dimensional(2 D) large-scale antenna array is deployed at base station(BS). An approximation of user's signal-tointerference-plus-noise ratio(SINR) and a lower bound of user's average signal-to-leakage-plus-noise ratio(SLNR) are derived. Based on these, two user scheduling algorithms exploiting only statistical channel state information(CSI) are proposed. The proposed algorithms take both the achievable sum rate and fairness into account. Simulation results reveal that the proposed user scheduling algorithms can make good trade-off between the achievable rate and fairness.

关键词： scheduling FD-MIMO fairness Rician fading

Identification of the hydrogen utilization pathway for the electrocatalytic hydrogenation of phenol

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Science China Chemistry 2021年第9期64卷 1586-1595页

作者： Ling Zhou Xiaorong Zhu Hui Su Hongzhen Lin Yanhong lyu Xu Zhao Chen Chen nana Zhang Chao Xie Yingying Li Yuxuan Lu Jianyun Zheng Benrt Johannessen San Ping Jiang Qinghua Liu Yafei Li Yuqin Zou Shuangyin Wang State Key Laboratory of Chem/Bio-Sensing and Chemometrics Provincial Hunan Key Laboratory for Graphene Materials and DevicesCollege of Chemistry and Chemical Engineeringthe National Supercomputer Centers in ChangshaHunan UniversityChangsha410082China College of Chemistry and Materials Science Nanjing Normal UniversityNanjing210023China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei230026China i-LAB Suzhou Institute of Nano-Tech and Nano-Bionics(SINANO)Chinese Academy of SciencesSuzhou215123China Department of Educational Science Hunan First Normal UniversityChangsha410205China Australian Synchrotron ClaytonVictoria3168Australia Western Australian School of Mines:Minerals Energy and Chemical Engineering and Fuels and Energy Technology InstituteCurtin UniversityPerthWA6102Australia

Electrochemical hydrogenation(ECH)of biomass-derived platform molecules is a burgeoning route for the sustainable utilization of ***,the noble-metal-catalyzed ECH of phenolic compounds suffers from intense competition with hydrogen evolution *** prepared Pt Rh bimetallic nanoparticles dispersed on highly ordered mesoporous carbon nanospheres,which improves the utilization efficiency of adsorbed hydrogen(H_(ad))to ECH in H-UPD region(>0 V ***).Further analysis reveals(i)the strong overlapping between the d-orbitals of Pt and Rh enhances specific adsorption of phenol;(ii)incorporation of Rh devotes an electronic effect on weakening the alloy-H_(ad)interaction to increase the FE of *** calculations confirm the selectivity difference and the ECH parallel pathways:cyclohexanol and cyclohexanone are formed via hydrogenation/dehydrogenation of the intermediate ^(*)C_(6)H_(10) *** findings deepen our fundamental understanding of the ECH process,and cast new light on exploration of highly efficient electrocatalysts for biomass upgrading.

关键词： electrohydrogenation aromatic hydrogenation biomass conversion Pt Rh alloy

Tunneling, Information Asymmetry, and Private Placement Discounts

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Frontiers of Business Research in China 2012年第3期6卷 325-346页

作者： Dan He nana Wang School of Business Southwestern University of Finance and EconomicsChengdu 611130China

Private placement has become an increasingly important method of equity refinancing for regulators, listed companies, and investors. This paper analyzes factors influencing private placement discounts based on the controlling shareholder＇s opportunistic behavior and information asymmetry. Our findings indicate that the type of subscriber is a key determinant of the private placement discount, particularly when the subscriber is the controlling shareholder. Asymmetric information between listed companies and investors is another important determinant： The higher the degree of information asymmetry, the greater the private placement discounts.

关键词： tunneling information asymmetry private placement discount

CFD simulation of particle suspension in a stirred tank

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Particuology 2013年第3期11卷 317-326页

作者： nana Qi Hu Zhang Kai Zhang Gang Xu Yongping Yang State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University School of Chemical Engineering The University of Adelaide

Particle suspension characteristics are predicted computationally in a stirred tank driven by a Smith turbine. In order to verify the hydrodynamic model and numerical method, the predicted power number and flow pattern are compared with designed values and simulated results from the literature, respectively. The effects of particle density, particle diameter, liquid viscosity and initial solid loading on particle suspension behavior are investigated by using the Eulerian-Eulerian two-fluid model and the standard k-ε turbulence model. The results indicate that solid concentration distribution depends on the flow field in the stirred tank. Higher particle density or larger particle size results in less homogenous distribution of solid particles in the tank. Increasing initial solid loading has an adverse impact on the homogeneous suspension of solid particles in a low-viscosity liquid, whilst more uniform particle distribution is found in a high-viscosity liquid.

关键词： Stirred tank Smith turbine Particle suspension CFD simulation

Software Defect Prediction Based on Stacked Contractive Autoencoder and Multi-Objective Optimization

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Computers, Materials & Continua 2020年第10期65卷 279-308页

作者： nana Zhang Kun Zhu Shi Ying Xu Wang School of Computer Science Wuhan UniversityWuhan430072China Department of Computer Science Vrije University AmsterdamAmsterdam1081HVThe Netherlands

Software defect prediction plays an important role in software quality ***,the performance of the prediction model is susceptible to the irrelevant and redundant *** addition,previous studies mostly regard software defect prediction as a single objective optimization problem,and multi-objective software defect prediction has not been thoroughly *** the above two reasons,we propose the following solutions in this paper:(1)we leverage an advanced deep neural network-Stacked Contractive AutoEncoder(SCAE)to extract the robust deep semantic features from the original defect features,which has stronger discrimination capacity for different classes(defective or non-defective).(2)we propose a novel multi-objective defect prediction model named SMONGE that utilizes the Multi-Objective NSGAII algorithm to optimize the advanced neural network-Extreme learning machine(ELM)based on state-of-the-art Pareto optimal solutions according to the features extracted by *** mainly consider two *** objective is to maximize the performance of ELM,which refers to the benefit of the SMONGE *** objective is to minimize the output weight norm of ELM,which is related to the cost of the SMONGE *** compare the SCAE with six state-of-the-art feature extraction methods and compare the SMONGE model with multiple baseline models that contain four classic defect predictors and the MONGE model without SCAE across 20 open source software *** experimental results verify that the superiority of SCAE and SMONGE on seven evaluation metrics.

关键词： Software defect prediction deep neural network stacked contractive autoencoder multi-objective optimization extreme learning machine

The Analysis of Secure HARQ with Chase Combining over Block Fading Channel

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China Communications 2016年第5期13卷 82-88页

作者： Yue Wu Lukman A Olawoyin nana Zhang Hongwen Yang Wireless Communication Center School of Information and Communication EngineeringBeijing University of Posts and Telecommunications

In this letter, the physical layer security of hybrid automatic repeat request with chase combining(HARQ-CC) scheme is investigated from the viewpoint of information theory. Different from the literature which used Wyner code, our analysis focuses on the general scenario without specific code. We firstly obtain the outage probability of both main channel and wiretap channel. Since retransmissions are completely determined by main channel, we then prove that its achievable diversity order equals to maximum transmission number() while this order of wiretap channel is only one. Furthermore, we evaluate the metric of secure gap which demonstrates the difference between main channel and wiretap channel with reliable and secure constraints. As increases, the secure gap decreases monotonously. When is large enough, the security can be guaranteed even if wiretap channel is better than main channel.

关键词： physical layer security HARQ chase combining outage probability diversity order secure gap

Structure optimization of gas-liquid combined loop reactor using a CFD-PBE coupled model

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Petroleum Science 2012年第3期9卷 379-388页

作者： Qi nana Zhang Kai Xu Gang Yang Yongping Zhang Hu School of Energy Power and Mechanical Engineering North China Electric Power UniversityBeijing 102206China School of Chemical Engineering University of AdelaideSouth AustraliaSA 5005Australia

Flow characteristics, such as flow pattern, gas holdup, and bubble size distribution, in an internal loop reactor with external liquid circulation, are simulated to investigate the influence of reactor internals by using the computational fluid dynamics （CFD）-population balance equations （PBE） coupled model. Numerical results reveal that introducing a downcomer tube and a draft tube can help to improve the mass and heat transfer of the reactor through enhanced liquid circulation, increased gas holdup and reduced bubble diameter. The hydrodynamic behavior in the internal loop reactor with external liquid circulation can be managed effectively by adjusting the diameter and axial position of the draft tube.

关键词： Loop reactor Structure optimization Hydrodynamics CFD-PBE coupled model

From nanoparticles to single atoms for Pt/CeO2:Synthetic strategies,characterizations and applications

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Journal of Rare Earths 2020年第8期38卷 850-862,I0002页

作者： Ying Xin nana Zhang Yanan Lv Jin Wang Qian Li Zhaoliang Zhang Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials School of Chemistry and Chemical EngineeringUniversity of JinanJinan 250022China

Pt/CeO2 catalysts with unitary Pt species,nanoparticles,clusters or single atoms,often exhibit excellent activity and unique selectivity in many catalytic reactions benefiting from their small size,abundant unsaturated active sites,and unique electro nic *** recent years,a tre mendous number of related articles have provided great inspiration to future research and development of Pt/CeO2 *** this review,the state-of-the-art evolution of Pt nanoparticles to Pt single atoms on CeO2 is reviewed with the emphasis on synthetic strategies,advanced characterization techniques(allowing one to clarify the single atoms from clusters),the catalytic applications and mechanisms from the viewpoint of theoretical ***,the critical outlooks and the challenges faced in developing the single-atom Pt/CeO2 catalysts are highlighted.

关键词： Pt/CeO2 Single atoms Cluster Synthetic strategy Characterization Application