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Structure of the mantle transition zone in the central and western parts of the North China Craton using the receiver function 3D Kirchhoff migration method

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Science China Earth Sciences 2024年第9期67卷 2783-2795页

作者： Min ZHU Qingju wu Jieyuan NING Ruiqing ZHANG Institute of Geophysics China Earthquake AdministrationBeijing 100081China Institute of Theoretical and Applied Geophysics Peking UniversityBeijing 100871China

Using data from the regional broadband dense temporary array deployed by the ChinArray project,we applied the three-dimensional(3D)Kirchhoff migration method of the teleseismic P-wave receiver function to investigate discontinuity structures of the mantle transition zone(MTZ)in the central and western parts of the North China Craton(NCC)using a highresolution 3D velocity model of the East Asian *** results show that the 410-km discontinuity beneath the Datong Volcano is depressed by~10 km,indicating the presence of a high-temperature anomaly near the depth of 410 km,which is likely related to small-scale mantle upwelling caused by the dehydration of the stagnant Pacific Plate in the *** upwelling of hot material provides a heat source for surface magmatic *** the Bohai Bay Basin,significant subsidence of the 660-km discontinuity is observed,and the transition zone here is extensively ***’s suggested that the anomalies in this region are related to the stagnation of the Pacific slab in the *** the thickness of the transition zone west of the North-South Gravity Lineament appears normal,we propose that the subducting front of the Pacific slab did not cross the gravity lineament in the *** comparison,the small-scale subsidence of the 660-km discontinuity and the thickening of the MTZ observed north of the Hannuoba Volcano likely indicate that the slab crossed the gravity lineament at its turning point and remained in the ***,a local thickening of the MTZ is observed in the Dabie orogenic belt of the Qinling *** is believed to be a combined effect of lithospheric delamination into the transition zone in the lower Yangtze region and the stagnation of the Pacific Plate.

关键词： North China Craton Mantle transition zone Receiver function migration Datong Volcano

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Design of communication relay mission for supporting lunar-farside soft landing

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Science China(Information Sciences) 2018年第4期61卷 73-86页

作者： Weiren wu Yuhua TANG Lihua ZHANG Dong QIAO Lunar Exploration Program and Space Engineering Center School of Aerospace Engineering Beijing Institute of Technology Dong Fang Hong Satellite Co.Ltd. Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information Technology

Chang’E-IV will be the first soft-landing and rover mission on the lunar farside. The relay satellite, which is located near the Earth-Moon L2 point for relay communication, is the key to the landing mission. Based on an analysis of the characteristics of the task and the technical difficulties associated with the relay satellite system, the overall design scheme of the relay communication mission is proposed in terms of trajectory design and communication system design among other aspects. First, according to the complex dynamic environment, a mission orbit that serves as an uninterrupted communication link is presented. A short-duration and low-energy transfer trajectory with lunar flyby is discussed. Orbital correction and a low-cost control strategy for orbit maintenance in the Earth-Moon L2 point region are provided. Second,considering the existing technical constraints, the requirement of relay communication in different stages and the design schemes of frequency division and redundant relay communication system are introduced. Finally,based on the trajectory design index and the performance of the communication system, the overall design scheme of the relay communication mission is proposed. This mission will provide the technical support and reference required for the Chang’E-IV mission.

关键词： lunar farside soft landing relay communication Earth-Moon Lagrange point

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Can the efficiencies of simplified perovskite solar cells go higher?

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Journal of Energy Chemistry 2021年第7期30卷 33-36页

作者： Jin-Feng Liao Wenhuai Feng Jun-Xing Zhong Bing-Xin Lei wu-Qiang wu Key Laboratory of Bioinorganic and Synthetic Chemistry(MOE) School of ChemistrySun Yat-sen UniversityGuangzhou 510275GuangdongChina School of Chemistry and Chemical Engineering Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan ProvinceHainan Normal UniversityHaikou 571158HainanChina

In recent years, metal halide perovskites have emerged as star semiconducting materials in the field of optoelectronic devices owing to their fascinating optoelectronic properties. Of particular interest are perovskite solar cells (PSCs), which have witnessed skyrocketing power conversion efficiencies (PCEs) within a short period of time, and were recently certified to reach 25.5%, which is already higher than other thin film photovoltaic technologies[1]. Nevertheless, multiple layers are still needed for state-of-theart PSCs to achieve high PCEs over 21%.

关键词： Perovskite solar cells Charge extraction Charge recombination Interfacial modification Energy level alignment

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Mechanistic identification of cutting force coefficients in bull-nose milling process

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Chinese Journal of Aeronautics 2013年第3期26卷 823-830页

作者： Gao Ge wu Baohai Zhang Dinghua Luo Ming The Key Laboratory of Contemporary Design and Integrated Manufacturing Technology Ministry of Education Northwestern Polytechnical University

An improved method to determine cutting force coefficients for bull-nose cutters is proposed based on the semi-mechanistic cutting force model. Due to variations of cutting speed along the tool axis in bull-nose milling, they affect coefficients significantly and may bring remarkable discrepancies in the prediction of cutting forces. Firstly, the bull-nose cutter is regarded as a finite number of axial discs piled up along the tool axis, and the rigid cutting force model is exerted. Then through discretization along cutting edges, the cutting force related to each element is recalculated, which equals to differential force value between the current and previous elements. In addition, coefficient identification adopts the cubic polynomial fitting method with the slice elevation as its horizontal axis. By calculating relations of cutting speed and cutting depth, the influences of speed variations on cutting force can be derived. Thereby, several tests are conducted to calibrate the coefficients using the improved method, which are applied to later force predictions. Eventually, experimental evaluations are discussed to verify the effectiveness. Compared to the conventional method, the results are more accurate and show satisfactory consistency with the simulations. For further applications, the method is instructive to predict the cutting forces in bull-nose milling with lead or tilt angles and can be extended to the selection of cutting parameters.

关键词： Bull-nose cutter Calibration Cutting force Cutting force coefficient Mechanistic model

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A regulated digital currency

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Science China(Information Sciences) 2019年第3期62卷 119-130页

作者： Yanbing wu Haining FAN Xiaoyun WANG Guangnan ZOU Institute for Advanced Study Tsinghua University Department of Computer Science and Technology Tsinghua University Space Star Technology Co. Ltd

The decentralized digital currency Bitcoin is an anonymous alternative to the centralized banking system and enjoys widespread and increasing adoption. Since Bitcoin created, many other electronic currencies have been developed. We propose a protocol for an electronic currency for making anonymous payments that can be supervised by an auditor, who has sole access to the transaction history. Other electronic currencies provide only anonymity, which is convenient for making illegal transactions without regulation. For users, miners, and banks, the transactions of our electronic currency are anonymous, and only auditors can see how it is used. We make use of POW(prove-of-work) technique that allows for distributed decisionmaking within a network, namely the Bitcoin blockchain protocol. We combine the POW and blockchain technology of Bitcoin to give better protection against double-spending attacks.

关键词： Blockchain Bitcoin anonymous digital currency regulated proof-of-work

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The ANOVA-Type Inference in Linear Mixed Model with Skew-Normal Error

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Journal of Systems Science & Complexity 2017年第3期30卷 710-720页

作者： wu Mixia ZHAO Jing WANG Tonghui ZHAO Yan College of Applied Sciences Beijing University of Technology Department of Mathematical Sciences New Mexico State University

Linear mixed effect models with skew-normal errors and distribution-free random effects are considered. The ANOVA-type F-tests are proposed to test the significance of random effects and the hypothesis on fixed effects of interest, respectively. Both tests are proved to be exact F-tests under this model, and the exact confidence interval for fixed effects of interest is derived. Simulation results are given to study the powers of ANOVA-type tests.

关键词： ANOVA-type estimator ANOVA-type F-test skew-normal error.

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Hydrophobic nanocellulose aerogels with high loading of metal-organic framework particles as floating and reusable oil absorbents

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Frontiers of Chemical Science and Engineering 2021年第5期15卷 1158-1168页

作者： Jiajia Li Shengcheng Zhai Weibing wu Zhaoyang Xu Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forestry Resources College of Materials Science and EngineeringNanjing Forestry UniversityNanjing210037China College of Light Industry and Food Engineering Nanjing Forestry UniversityNanjing210037China

In this paper,we employed a facile approach to prepare flexible and porous metal-organic frameworks(MOFs)containing cellulose nanofiber(CNF)aerogels(MNCAs)through freeze-drying MOF-containing cellulose nanofiber *** coating with methyltrimethoxysilane(MTMS)by chemical vapor deposition,recycled and hydrophobic MTMS-coated MNCAs(MMNCAs)were *** to the low density(0.009 g/cm^(3)),high porosity(97%)and good mechanical properties of the aerogel,the adsorption capacity of MMNCAs reached up to 210 g/g,which was nearly 3–5 times that of pure CNF *** prepared aerogels showed excellent oil/water selectivity and high capacity to adsorb oil and organic *** kind of cellulose-based aerogel may be applicable in the field of environmental protection.

关键词： cellulose nanofibers aerogels metal-organic framework oil-adsorption

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Experimental investigations on cavity-actuated under-expanded supersonic oscillating jet

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Chinese Journal of Aeronautics 2015年第5期28卷 1372-1380页

作者： Sun Bo Luo Xiaochen Feng Feng wu Xiaosong Department of Aerospace Engineering Nanjing University of Science and Technology

As one type of potential flow control actuators, cavity-actuated supersonic jet oscillators, which consist of a 2-D convergent nozzle and two face to face cavities, need to be investigated dee- ply to get the knowledge of their oscillating feature and underlying mechanism. Wind tunnel testing are conducted under different back pressures in a vacuum-type wind tunnel for two supersonic jet oscillators, to obtain their characteristics and the conditions for jet oscillating. The experimental results show that the continuous, nearly symmetric or asymmetric flipping between the two cavities appears over certain nozzle pressure ratio （NPR） range for both oscillators according to schlieren visualizations. Compared to the free jet, the oscillating jet with large exit achieves larger mixing; the oscillating jet with small exit has less mixing, based on the analysis of jet axial peak velocity and the entrainment. The cross-junction mode for estimating the resonance frequency in a pipe with two closed side branches is modified and obtained comparable estimations of the frequency of jet flipping with experimental data, but further investigations are needed to discover the underlying mechanism for the jet flipping.

关键词： Jet cavity interactions Jet flipping Oscillating jet Supersonic jet Wind-tunnel testing

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Recent advances in post-chiroptical manipulation of supramolecular aggregates assembled with molecular modules

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Science China Chemistry 2024年第9期67卷 2842-2863页

作者： Yanling Shen Wanhua wu Zhipeng Yu Cheng Yang Key Laboratory of Green Chemistry&Technology of Ministry of Education College of Chemistry InstitutionSichuan UniversityChengdu 610064China

Recently,various supramolecular assembly systems have been identified where the pre-existing chiral supramolecular structure can be manipulated through environmental adjustments,such as temperature,solvent,and *** changes result in diverse microscopic morphologies during the assembly process and induce chiroptical variations,particularly in circular dichroism(CD)and circularly polarized luminescence(CPL)*** chiroptical properties serve as direct indicators of the chiral supramolecular structure and hold promise for applications in sensing,molecular recognition,asymmetric synthesis,and material *** review focuses on research published in the last five years,highlighting instances where assembled structures aggregated by small organic molecular modules demonstrate in-situ chiroptical changes through external condition *** categorizes and discusses different modes of regulation,aiming to offer insights and guidelines for exploring dynamic changes in assembly processes and designing in-situ adjustable structures of assembly modules.

关键词： supramolecular assemblies post-chiroptical manipulation in-situ structural changes

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A QUANTUM MULTI-AGENT BASED NEURAL NETWORK MODEL FOR FAILURE PREDICTION

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Journal of Systems Science and Systems Engineering 2016年第2期25卷 210-228页

作者： Wei wu Min Liu Qing Liu Weiming Shen School of Electronic and Information Engineering Tongji University Shanghai 201804 China The Key Laboratory of Embedded System and Service Computing Ministry of EducationTongji University Shanghai 200092 China

An effective prognostic program is crucial to the predictive maintenance of complex equipment since it can improve productivity, prolong equipment life, and enhance system safety. This paper proposes a novel technique for accurate failure prognosis based on back propagation neural network and quantum multi-agent algorithm. Inspired by the extensive research of quantum computing theory and multi-agent systems, the technique employs a quantum multi-agent strategy, with the main characteristics of quantum agent representation and several operations including fitness evaluation, cooperation, crossover and mutation, for parameters optimization of neural network to avoid the deficiencies such as slow convergence and liability of getting stuck to local minima. To validate the feasibility of the proposed approach, several numerical approximation experiments were firstly designed, after which real vibrational data of bearings from the Laboratory of Cincinnati University were analyzed and used to assess the health condition for a given future point. The results were rather encouraging and indicated that the presented forecasting method has the potential to be utilized as an estimation tool for failure prediction in industrial machinery.

关键词： Failure prediction complex equipment quantum-inspired multi-agent algorithm back propagation neural network

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