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Tribological study on the surface modification of metal-on-polymer bioimplants

Frontiers of Mechanical engineering 2022年第2期17卷 103-115页

作者： Gang SHEN Jufan ZHANG David CULLITON Ruslan MELENTIEV Fengzhou FANG Centre of Micro/Nano Manufacturing Technology(MNMT-Dublin) School of Mechanical and Materials EngineeringUniversity College DublinDublin 4Ireland Department of Aerospace Mechanical and Electronic EngineeringInstitute of Technology CarlowCarlowIreland State Key Laboratory of Precision Measuring Technology and Instruments Centre of Micro/Nano Manufacturing Technology(MNMT)Tianjin UniversityTianjin 300072China

The tribological performance of artificial joints is regarded as the main factor of the lifespan of implanted prostheses. The relationship between surface roughness and coefficient of friction (COF) under dry and lubricated conditions is studied. Results show that under dry test, friction coefficient is not reduced all the time with a decrease in surface roughness. On the contrary, a threshold of roughness value is observed, and frictional force increases again below this value. This critical value lies between 40 and 100 nm in Sa (roughness). This phenomenon is due to the transfer of friction mechanisms from abrasion to adhesion. Under wet test, COF always decreases with reduction in surface roughness. This result is mainly attributed to the existence of a thin layer of lubricant film that prevents the intimate contact of two articulating surfaces, thus greatly alleviating adhesion friction. Furthermore, surface texturing technology is successful in improving the corresponding tribological performance by decreasing friction force and mitigating surface deterioration. The even-distribution mode of texturing patterns is most suitable for artificial joints. By obtaining the optimal surface roughness and applying texturing technology, the tribological performance of polymer-based bioimplants can be greatly enhanced.

关键词： artificial joints surface roughness friction surface texturing

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Toward high efficiency for content-based multiattribute event matching via hybrid methods

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Science China(information Sciences) 2016年第2期59卷 201-216页

作者： Wenhao FAN Yuanan LIU Bihua TANG school of electronic engineering Beijing University of Posts and Telecommunications Beijing Key Laboratory of Work Safety Intelligent Monitoring Beijing University of Posts and Telecommunications

Event matching is a core in decoupled end-to-end communications, which are extensively applied to various areas. Event matching seeks the subscriptions that match a given event from a subscription set,however, this work becomes increasingly complicated in content-based multi-attribute scenarios, where events and subscriptions are formed in content, and described by multiple attributes. In addition, large-scale systems are easier to suffer from severe degradation in event matching performance. To this end, this paper presents a high-efficiency content-based multi-attribute event matching algorithm, called HEM(hybrid event matching),which is hybridized by 2 different methods. In HEM, the matching on each single attribute(called singleattribute matching) is processed by a triangle-based matching method or a direct matching method *** single-attribute matchings are sorted via a fast near-optimal algorithm, and each of them is carried out sequentially. In this manner, the searching space of event matching shrinks gradually, so that the searching performance is boosted along with the process of event matching. Experiments are conducted to evaluate HEM comprehensively, where it is observed that HEM outperforms 3 state-of-the-art counterparts(TAMA, H-TREE and REIN) in main criteria, such as event matching time, insertion time and deletion time. Moreover, the gap of performance between HEM and the counterparts enlarges with the increase of system scale.

关键词： event matching publish/subscribe data dissemination end-to-end communications interval search combinatorial optimization

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Puncturable ciphertext-policy attribute-based encryption scheme for efficient and flexible user revocation

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Science China(information Sciences) 2023年第7期66卷 130-146页

作者： Dilxat GHOPUR Jianfeng MA Xindi MA Yinbin MIAO Jialu HAO Tao JIANG school of Cyber engineering Xidian University Guangxi Key Laboratory of Trusted Software Guilin University of Electronic Technology Xi'an Satellite Control Center

With the rapid deployment of storage services, secure and efficient user authorization and revocation data shared through the cloud have become a grand challenge hindering cloud data *** previous direct and indirect user revocation schemes implemented large-scale user revocation, they faced heavy communication and computational costs. To address these challenges, this study presents a new encryption scheme that combines ciphertext-policy attribute-based encryption(CP-ABE) with puncturable encryption to achieve efficient and flexible user revocation. We design a proxy server to reduce the computational overhead in the decryption phase. Because the puncture process is performed on a semi-honest cloud, we use the digital signature method to verify the correctness of its operation. Furthermore, we prove the security of our scheme under the chosen-plaintext attack(CPA), and compare it with other schemes to highlight its advantages. Numerical analysis and experimental simulation results reveal that our scheme is more suitable than other schemes for use in a cloud environment for user revocation.

关键词： ciphertext-policy attribute-based encryption puncturable encryption user revocation outsource decryption digital signature

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Corpus-based research on English word recognition rates in primary school and word selection strategy

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Frontiers of information Technology & electronic engineering 2017年第3期18卷 362-372页

作者： Wen-yan XIAO Ming-wen WANG Zhen WENG Li-lin ZHANG Jia-li ZUO school of Computer information engineering Jiangxi Normal UniversityNanchang 330022China Jiangxi university of Science and Technology Nanchang 330003China

Acquiring vocabulary is important when studying English, as it assists in listening, speaking, reading, and writing. In this paper, we develop an English webpage corpus(EWC) and create a word frequency list using web crawler technology. By comparing EWC word lists with the British National Corpus(BNC), we find that the BNC word frequency list possesses the feature of timeliness. We also explore primary school students' English word recognition rates by comparing the word frequency lists of several corpora, including EWC, BNC, SUBTLEX-US, and Subtitle Corpus of Children's BBC(CBBC). The results show that the word recognition rates for primary school children are relatively low in both general language and specific language register. Motivated by the experiment results, we finally propose some word-selection strategies for compiling English textbooks for Chinese primary school students.

关键词： Corpus Primary English Recognition rate Word frequency Coverage rate

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Communication-efficient federated continual learning for distributed learning system with Non-IID data

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Science China(information Sciences) 2023年第2期66卷 94-113页

作者： Zhao ZHANG Yong ZHANG Da GUO Shuang ZHAO Xiaolin ZHU school of electronic engineering Beijing University of Posts and Telecommunications Beijing Key Laboratory of Work Safety Intelligent Monitoring Beijing University of Posts and Telecommunication

Due to the privacy preserving capabilities and the low communication costs, federated learning has emerged as an efficient technique for distributed deep learning/machine learning training. However, given the typical heterogeneous data distributions in the realistic scenario, federated learning faces the challenge of performance degradation on non-independent identically distributed(Non-IID) data across clients. Therefore, we propose federated continual learning to improve the performance on Non-IID data by introducing the knowledge of the other local models. Specifically, we propose a novel federated continual learning method called Fed SI, adapting the synaptic intelligence method to the federated learning scenario. Furthermore,in order to reduce the communication overheads, we propose the bidirectional compression and error compensation(BCEC) algorithm to produce the communication-efficient federated continual learning method,called CFedSI. Specifically, the proposed BCEC algorithm compresses both the uplink and the downlink transmission data and utilizes the error compensation locally to ensure training divergence. Experiments show that CFedSI improves the accuracy on Non-IID data by up to 46% with KDDCUP’99 dataset, 23%with CICIDS2017 dataset, 22% with MNIST dataset, and 8% with FashionMNIST dataset, along with the reduced communication overheads.

关键词： distributed learning system federated learning continual learning model compression error compensation

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A New Probabilistic Transformation in Generalized Power Space

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Chinese Journal of Aeronautics 2011年第4期24卷 449-460页

作者： HU Lifang HE You GUAN Xin DENG Yong HAN Deqiang Research Institute of information Fusion Naval Aeronautical and Astronautical University Yantai 264001 China Sche Institute of electronic Science and engineering National University of Defense Technology Changsha 410073 China school of electronics and information Technology Shanghai Jiao Tong University Shanghai 200240 China Institute of Integrated Automation Xi 'an Jiaotong University Xi'an 710049 China

The mapping from the belief to the probability domain is a controversial issue, whose original purpose is to make （hard） decision, but for contrariwise to erroneous widespread idea/claim, this is not the only interest for using such mappings nowadays. Actually the probabilistic transformations of belief mass assignments are very useful in modern multitarget multisensor tracking systems where one deals with soft decisions, especially when precise belief structures are not always available due to the existence of uncertainty in human being’s subjective judgments. Therefore, a new probabilistic transformation of interval-valued belief structure is put forward in the generalized power space, in order to build a subjective probability measure from any basic belief assignment defined on any model of the frame of discernment. Several examples are given to show how the new transformation works and we compare it to the main existing transformations proposed in the literature so far. Results are provided to illustrate the rationality and efficiency of this new proposed method making the decision problem simpler.

关键词： Dempster-Shafer theory generalized power space information fusion interval value uncertainty

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Simultaneous polarization separation and switching for 100-Gbps DP-QPSK signals in backbone networks

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Chinese Physics B 2019年第2期28卷 299-305页

作者： Yu-Long Su Huan Feng Hui Hu Wei Wang Tao Duan Yi-Shan Wang Jin-Hai Si Xiao-Ping Xie He-Ning Yang Xin-Ning Huang State Key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision MechanicsChinese Academy of Sciences Key Laboratory for Physical electronics and Devices of the Ministry of Education and Shaanxi Key Laboratory of information Photonic Technique School of Electronic and Information EngineeringXi'an Jiaotong University university of Chinese Academy of Sciences

We propose a novel scheme of simultaneous polarization separation and switching, based on the orthogonallypolarized four-wave mixing(FWM) effect, for ultra-high-speed polarization multiplexing(Pol-MUX) fiber networks such as 100-Gbps and 400-Gbps backbone networks. We use theoretical and experimental analysis of the vector theory of FWM to successfully achieve polarization separation and all-optical switching by utilizing a 100-Gbps dual polarizationquadrature phase shift keying(DP-QPSK) signal and two orthogonally-polarized pumps. Both of the polarization-separated QPSK signals have clear constellation diagrams, with root mean square(RMS) error vector magnitudes(EVMs) of 14.32%and 14.11% respectively. The wavelengths of idlers can be created at 30 different wavelengths, which are consistent with International Telecommunication Union-Telecommunication(ITU-T) wavelengths, by flexibly changing the wavelength of the pump light. Moreover, the idlers that have distinct wavelengths have power distributed in a range from-10 dBm to-15 dBm, which can support error-free transmission. The power penaltyis 5 d B lower than that of back-to-back(BTB)signal for both the X-and Y-polarization components measured at a bit error ratio(BER) of 3.8×10^(-3). Our experimental results indicate that this scheme has promising applications in future backbone networks.

关键词： polarization separation and switching four-wave mixing orthogonal polarization 100-Gbps dual polarization-quadrature phase shift keying

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Top gate engineering of field-effect transistors based on wafer-scale two-dimensional semiconductors

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Journal of Materials Science & Technology 2022年第11期106卷 243-248页

作者： Jingyi Ma Xinyu Chen Yaochen Sheng Ling Tong Xiaojiao Guo Minxing Zhang Chen Luo Lingyi Zong Yin Xia Chuming Sheng Yin Wang Saifei Gou Xinyu Wang Xing Wu Peng Zhou David Wei Zhang Chenjian Wu Wenzhong Bao State Key Laboratory of ASIC and System School of MicroelectronicsFudan UniversityShanghai200433China In Situ Devices Center Shanghai Key Laboratory of Multidimensional Information ProcessingEast China Normal UniversityShanghai 200241China school of electronic information Soochow UniversitySuzhou215006China

The investigation of two-dimensional(2D)materials has advanced into practical device applications,such as cascaded logic ***,incompatible electrical properties and inappropriate logic levels remain enormous *** this work,a doping-free strategy is investigated by top gated(TG)MoS_(2) field-effect transistors(FETs)using various metal gates(Au,Cu,Ag,and Al).These metals with different work functions provide a convenient tuning knob for controlling threshold voltage(V_(th))for MoS_(2) *** instance,the Al electrode can create an extra electron doping(n-doping)behavior in the MoS_(2) TG-FETs due to a dipole effect at the gate-dielectric *** this work,by achieving matched electrical properties for the load transistor and the driver transistor in an inverter circuit,we successfully demonstrate wafer-scale MoS_(2) inverter arrays with an optimized inverter switching threshold voltage(V_(M))of 1.5 V and a DC voltage gain of 27 at a supply voltage(V_(DD))of 3 *** work offers a novel scheme for the fabrication of fully integrated multistage logic circuits based on wafer-scale MoS_(2) film.

关键词： Two-dimensional semiconductor MoS_(2) Top gate Field effect transistor Logic inverter

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Fabrication of flexible α-MnO_2 nanowire membranes with superior mechanical strength

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Chinese Science Bulletin 2014年第13期59卷 1454-1458页

作者： Xingyue Zhao Xiaochong Zhao Jianbao Li Xiangyun Deng Hong Lin State Key Laboratory of New Ceramics & Fine Processing School of Materials Science and Engineering Tsinghua University Science and Technology on Surface Physics and Chemistry Laboratory Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island Resources Hainan University College of Physics and electronic information Tianjin Normal University

The Assembly of one-dimensional(1D)nanostructures such as nanowires/nanorods/nanotubes into twodimensional(2D)macrostructured films is attracting considerable research interest because of their unique properties and wide *** this study,flexible membranes were successfully fabricated using a-MnO2nanowires synthesized through a hydrothermal *** effects of thickness and post-annealing temperature on the mechanical properties of the membranes were investigated in ***-indentation measurements showed that the modulus of the as-prepared 11.75 lm-thick membrane reached5.765 GPa,and the modulus increased with the increasing post-annealing ***,the fabricated membranes with superior mechanical strength can have potential applications such as in photocatalysis,filtering,and supporting substrates.

关键词：机械强度二氧化锰纳米线制造膜退火温度机械性能水热法合成

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Research on D2D Co-localization Algorithm Based on Clustering Filtering

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China Communications 2020年第8期17卷 121-132页

作者： Jiawen Zhang Fuxing Yang Zhongliang Deng Xiao Fu Jiazhi Han school of Automation Beijing University of Posts and TelecommunicationsBeijing 100876China school of electronic engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

Nowadays, most positioning systems carry out locational calculation based on the accurate location information of some devices in the network. However there is a deviation in the locational information of the part of the device, we need to reduce it in order to obtain higher positioning accuracy. In this paper, we proposed a new centralized D2D(Device-to-Device) co-location algorithm. This algorithm uses DBSACN(Density-Based Spatial Clustering of Applications with Noise) clustering to reduce the deviation of device location information. Numerical results show that the positioning accuracy of the centralized D2D co-localization algorithm is improved by 62.7% compared with the SPAWN algorithm, which positioning performance superior to the traditional co-localization algorithm.

关键词： co-location D2D clustering DBSACN

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