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Nano Research 2023年第5期16卷 6251-6259页

作者： Qihong Yue Guoqing Li Ping Fu biao meng Fangpei Ma Yu Zhou Jun Wang State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 210009China

Photocatalytic hydrogen(H_(2))production from seawater over a photocatalyst is of great significance for the utilization of the earth’s abundant seawater resources and the storage of inexhaustible solar energy with low-energy ***,the designation of efficient photocatalytic systems by using seawater usually suffers from activation decline when replacing pure water with ***,we synthesized threeβ-ketoenamine-linked covalent organic frameworks(COFs),demonstrating their promotion in the photocatalytic decomposition of seawater relative to pure water under visible-light *** target COFs were synthesized via a microwave assisted solvothermal method by using 1,3,5-triformylphloroglucinol(Tp)as the aldehyde monomer to react with diamino units with different numbers of benzene *** surveying the building blocks,the constructed COF with a high density ofβ-ketoenamine units exhibited the so far highest photocatalytic H_(2) evolution rate(41.3 mmol·g^(−1)·h^(−1))in seawater,about 1.66 times higher than that in pure ***β-ketoenamine units allowed the in-situ polarization of the COF framework through the adsorption of metal salts when proceeding with the photocatalytic H_(2) production in *** polarization effect significantly increases the dielectric constant of the organic semiconductor to lower exciton dissociation energy and thus enhances the charge separation and transfer to promote the H_(2) photoproduction in seawater.

关键词： covalent organic frameworks photocatalysis hydrogen evolution reaction seawater polarization

Science Letters:Energy harvesting with a slotted-cymbal transducer

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第8期10卷 1187-1190页

作者： Jiang-bo yuan Xiao-biao SHAN Tao XIE Wei-shan CHEN Department of Mechatronics Engineering Harbin Institute of Technology Harbin 150001 China

A cymbal transducer is made up of a piezoceramic disk sandwiched between two dome-shaped metal *** circumferential stresses caused by flexural motion of the metal endcaps can induce the loss of mechanical input *** element analysis shows that the radial slots fabricated in metal endcaps can release the circumferential stresses,and reduce the loss of mechanical input energy that could be converted into electrical *** this letter,the performance of a slotted-cymbal transducer in energy harvesting was *** results show that the output voltage and power of the cymbal are improved.A maximum output power of around 16 mW could be harvested from a cymbal with 18 cone radial slots across a 500 kΩ resistive load,which is approximately 0.6 times more than that of the original cymbal transducer.

关键词： Piezoelectric Cymbal transducer Energy harvesting

Directional Modulation Based on a Quantum Genetic Algorithm for a Multiple-Reflection Model

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Computers, Materials & Continua 2020年第9期64卷 1771-1783页

作者： Yuwei Huang Xiubo Chen Kaiguo yuan Jianyi Zhang biao Liu Information Security Center State Key Laboratory of Networking and Switching TechnologyBeijing University of Posts and TelecommunicationsBeijing100876China Beijing Electronic Science and Technology Institute Beijing100070China Sate Key Laboratory of Public Big Data Guizhou UniversityGuiyang550025China School of Computing and Informatics The University of Louisiana at LafayetteLafayetteLA 70503USA.

Directional modulation is one of the hot topics in data security *** fulfill the requirements of communication security in wireless environment with multiple paths,this study takes into account the factors of reflections and antenna radiation pattern for directional *** other previous works,a novel multiple-reflection model,which is more realistic and complex than simplified two-ray reflection models,is proposed based on two *** focus is a quantum genetic algorithm applied to optimize antenna excitation in a phased directional modulation antenna *** quantum approach has strengths in convergence speed and the globe searching ability for the complicated model with the large-size antenna array and multiple *** this,a phased directional modulation transmission system can be optimized as regards communication safety and improve performance based on the constraint of the pattern of the antenna *** work can spur applications of the quantum evolutionary algorithm in directional modulation technology,which is also studied.

关键词： Directional modulation quantum genetic algorithm phased antenna array multiple reflection

Has LIGO detected primordial black hole dark matter?——tidal disruption in binary black hole formation

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Research in Astronomy and Astrophysics 2020年第11期20卷 303-311页

作者： yuan Gao Xiao-Jia Zhang meng Su Department of Physics The University of Hong KongHong Kong SARChina Department of Earth Sciences The University of Hong KongHong Kong SARChina Department of Physics and Laboratory for Space Research The University of Hong KongHong Kong SARChina

The frequent detection of binary mergers of^30 M⊙black holes(BHs)by the Laser Interferometer Gravitational-Wave Observatory(LIGO)rekindled researchers’interest in primordial BHs(PBHs)being dark matter(DM).In this work,we investigated PBHs distributed as DM with a monochromatic mass of 30 M⊙and examined the encounter-capture scenario of binary formation,where the densest central region of DM halo ***,we paid special attention to the tidal effect by the supermassive black hole(SMBH)*** doing so,we discovered a necessary tool called loss zone that complements the usage of loss *** found that the tidal effect is not prominent in affecting binary formation,which also turned out to be insufficient in explaining the totality of LIGO’s event rate estimation,especially due to a microlensing event constraining the DM fraction in PBH at the mass of interest from near unity to an order ***,an early-universe binary formation scenario proves so prevailing that the LIGO signal in turn constrains the PBH fraction below one ***,people should put more faith in alternative PBH windows and other DM candidates.

关键词： black hole physics dark matter gravitational waves quasars supermassive black holes

Primordial black holes generated by the non-minimal spectator field

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Science China(Physics,Mechanics & Astronomy) 2023年第8期66卷 42-50页

作者： De-Shuang meng Chen yuan Qing-Guo Huang CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou310024China

We improve and generalize the non-minimal curvaton model originally proposed in arXiv:2112.12680 to a model in which a spectator field non-minimally couples to an inflaton field and the power spectrum of the perturbation of spectator field at small scales is dramatically enhanced by the sharp feature in the form of non-minimal *** or after the end of inflation,the perturbation of the spectator field is converted into curvature perturbation and leads to the formation of primordial black holes(PBHs).Furthermore,for example,we consider three phenomenological models for generating PBHs with mass function peaked at~10^(-12) M_(⊙)and representing all the cold dark matter in our universe and find that the scalar induced gravitational waves generated by the curvature perturbation can be detected by the future space-borne gravitational-wave detectors such as Taiji,Tian Qin,and LISA.

关键词： primordial black holes non-minimal spectator field cold dark matter

Performance Evaluation with Improved Receiver Design for Asynchronous Coordinated Multipoint Transmissions

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Chinese Journal of Electronics 2016年第2期25卷 372-378页

作者： CAO yuan WEN Yinghong meng Xiangyang XU Wei National Engineering Research Center of Rail Transportation Operation and Control System. Beijing Jiaotong University School of Electronic and Information Engineering Beijing Jiaotong University National Mobile Communications Research Lab. Southeast University

Joint transmission is one of the ma jor transmission schemes in Coordinated multipoint(Co MP)transmission/reception systems for Long term evolutionadvanced(LTE-A). Due to different distances between User equipments(UE) and Base stations(BS), signals are not able to arrive at the receiver with perfect synchronization, which implies that the reception at UE is asynchronous. This paper presents an evaluation on asynchronous UE reception in multi-cell downlink joint transmission systems using our LTE-based Co MP ***, due to asynchronous reception, we propose an improved reception strategy to mitigate the interference which compensate for Rx timing difference on Joint transmission(JT) Co MP systems. Simulation results show that the per-subband global precoding scheme widely used in the Co MP system is considerably sensitive to asynchronous reception since the performance is dominated by the subcarrier used for precoding vector calculation. It is verified that our proposed solution is able to achieve significant improvements under asynchronous reception.

关键词： Joint transmission Asynchronous reception Global precoding CoMP

Integrated assessment of river health based on water quality, aquatic life and physical habitat

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Journal of Environmental Sciences 2009年第8期21卷 1017-1027页

作者： meng Wei ZHANG Nan ZHANG yuan ZHENG Binghui River and Costal Environmental Research Center China Research Academy of Environment Science Beijing 100012 China Key Laboratory of Water and Sediment Sciences College of Water Sciences Beijing Normal University Beijing 100875 China

The health conditions of Liao River were assessed using 25 sampling sites in April 2005, with water quality index, biotic index and physical habitat quality index. Based on the method of cluster analysis （CA） for water quality indices, it revealed that heavily polluted sites of Liao River are located at estuary and mainstream. The aquatic species surveyed were attached algae and benthic invertebrates. The result showed that the diversity and biomass of attached algae and benthic index of biotic integrity （B-IBI） were degrading as the chemical and physical quality of water bodies deteriorating. Physiochemical parameters, BODs, CODcr, TN, TP, NH3-N, DO, petroleum hydrocarbon and conductivity, were statistically analyzed with principal component analysis and correlation analysis. The statistical results were incorporated into the integrated assessing water quality index, combining fecal coliform count, attached algae diversity, B-IBI and physical habitat quality score. A comprehensive integrated assessing system of fiver ecological health was established. Based on the systimetic assessment, the assessed sites are categorized into 9 ＂healthy＂ and ＂sub-healthy＂ sites and 8 ＂sub-sick＂ and ＂sick＂ sites.

关键词： Liao River river health assessment benthic-index of biotic integrity water quality physical habitat conditions

Conductive Metal/Covalent Organic Frameworks for CO_(2) Electroreduction

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Chinese Journal of Structural Chemistry 2022年第5期41卷 1-14页

作者： Chang-Pu Wan Jun-Dong Yi Rong Cao yuan-biao Huang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China School of Chemistry and Materials Science Collaborative Innovation Center of Chemistry for Energy Materials(iChEM)University of Science and Technology of ChinaHefei 230026China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China

Porous crystalline metal-organic frameworks(MOFs)and covalent organic frameworks(COFs)are promising platforms for electrocatalytic reduction of CO_(2)(CO_(2)RR)due to their large CO_(2)adsorption uptakes and periodically arranged single active ***,the applications in CO_(2)RR of the traditional MOFs and COFs are greatly limited by their low electron *** recent years,numerous types of MOFs and COFs with high intrinsic conductivity have been rationally designed and successfully constructed,and some of them have been applied in CO_(2)*** this review,the applications of conductive MOFs and COFs in CO_(2)RR have been *** conductive MOFs and COFs can be categorized according to the methods,in which the conductivity is enhanced,such as constructing fullyπ-conjugated backbones,donor-acceptor heterojunction,enhancing theπ-πstacking interactions between organic moieties and/or the introduction of guest molecules.

关键词： metal-organic frameworks covalent organic frameworks CO_(2)electroreduction reaction conductive frameworks

Resilient tightly coupled INS/UWB integration method for indoor UAV navigation under challenging scenarios

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Defence Technology（防务技术） 2023年第4期22卷 185-196页

作者： Qian meng Yang Song Sheng-ying Li yuan Zhuang Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology Southeast UniversityNanjing210096China Department of Mechanical Engineering Hong Kong Polytechnic UniversityHong KongChina State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina

Based on the high positioning accuracy,low cost and low-power consumption,the ultra-wide-band(UWB)is an ideal solution for indoor unmanned aerial vehicle(UAV)localization and ***,the UWB signals are easy to be blocked or reflected by obstacles such as walls and furniture.A resilient tightly-coupled inertial navigation system(INS)/UWB integration is proposed and implemented for indoor UAV navigation in this paper.A factor graph optimization(FGO)method enhanced by resilient stochastic model is established to cope with the indoor challenging *** deal with the impact of UWB non-line-of-sight(NLOS)signals and noise uncertainty,the conventional neural net-works(CNNs)are introduced into the stochastic modelling to improve the resilience and reliability of the *** on the status that the UWB features are limited,a‘two-phase'CNNs structure was designed and implemented:one for signal classification and the other one for measurement noise *** proposed resilient FGO method is tested on flighting UAV platform under actual indoor challenging *** to classical FGO method,the overall positioning errors can be decreased from about 0.60 m to centimeter-level under signal block and reflection *** superiority of resilient FGO which effectively verified in constrained environment is pretty important for positioning accuracy and integrity for indoor navigation task.

关键词： Unmanned aerial vehicle(UAV) Resilient navigation Indoor positioning Factor graph optimization Ultra-wide band(UWB)

Bionic stab-resistant body armor based on triangular pyramid structure

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Defence Technology（防务技术） 2021年第3期17卷 792-799页

作者： Ya-xin Guo meng-qi yuan Xin-ming Qian State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China

A stab-resistant substrate was designed and realized with a triangular pyramidal structure, inspired by the biological armor model in nature. The stab-resistance behavior and dynamic response mechanisms were studied through numerical simulation and experimental testing of a knife impacting a substrate,and an optimal structural design was obtained accordingly, with a tilted angle of 22.5and optimal thickness of 1.2 mm. It was shown that the triangular pyramidal structure generated twice the internal energy of the knife than the flat substrate due to the dispersing effect of the structure. The force parallel to the inclination caused a significant scratch on the substrate surface, while the force perpendicular caused obvious substrate deformation. A new riveting method was used to form the total layer, which passed the GA 68-2008 standard. The stab-resistant clothing coupled with the reduced wearing burden could provide effective protection and avoid fatal injuries on security personnel working in dangerous environments. The method provided may enlighten the future design and manufacturing of stabresistant clothing.

关键词： Stab resistant Impact behavior Body armor Finite element analysis