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GLOBALLY ASYMPTOTICALLY STABLE FORMATION CONTROL OF THREE AGENTS

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Journal of Systems Science & Complexity 2012年第6期25卷 1068-1079页

作者： Qin WANG Yu-ping TIAN Yaojin xu School of Automation Southeast University

This paper considers the formatiomshape control of three agents in the plane. By adding an adaptive perturbation to any agent＇s movement direction, a novel control strategy is proposed. It is shown that the proposed novel control law can not only guarantee the global asymptotical stability of the desired formation shape, but also ensure the collision avoidance of agents between each other. Simulation results are provided to illustrate the effectiveness of the control algorithm.

关键词： Formation control global asymptotic stability multi-agents system.

LLMP： Exploiting LLDP for Latency Measurement in Software-Defined Data Center Networks

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Journal of Computer Science & Technology 2018年第2期33卷 277-285页

作者： Yang Li Zhi-ping Cai Hong xu College of Computer National University of Defense Technology Changsha 410073 China Department of Computer Science City University of Hong Kong Hong Kong 9990V7 China

The administrators of data center networks have to continually monitor path latency to detect network anomaly quickly and ensure the efficient operation of the networks. In this work, we propose Link Layer Measurement Protocol （LLMP）, a prototype latency measuring framework based on the Link Layer Discovery Protocol （LLDP）. LLDP is utilized by the controller to discover network topology dynamically. We insert timestamps into the optional LLDPTLV field in LLDP, so that the controller can estimate latency on any single link. The framework utilizes a reactive measurement approach without injecting any probe packets to the network. Our experiments show that the latency of a link can be measured accurately by LLMP. In relatively complex network conditions, LLMP can still maintain a high accuracy. We store the LLMP measurement results into a latency matrix, which can be used to infer the path latency.

关键词： software-defined network (SDN) Link Layer Discovery Protocol (LLDP) latency measurement

String and Ball-Like TiO_2/rGO Composites with High Photo-catalysis Degradation Capability for Methylene Blue

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Transactions of Tianjin University 2018年第3期24卷 272-281页

作者： Fengyun xu ping Na School of Chemical Engineering and Technology Tianjin University

Novelthree-dimensionalstring and ball-like titanium dioxide/reduced graphene oxide, TiO_2/rGO(STG) composites were prepared using a one-step hydrolysis process followed by a low-temperature hydrothermaltreatment. The STG composites exhibited excellent photo-catalytic degradation performance for methylene blue owing to a good synergistic effect between TiO_2 and rGO. The STG composites with 1.0 wt% of rGO loading exhibited the highest removalrate of 86.0% for methylene blue and its reaction rate constant(5.27 × 10^(-3) min^(-1)) was much higher than those of pure string and ball-like TiO_2(ST). In addition, the STG composites also showed an outstanding capability for the photo-catalysis degradation of other cationic dyes. In addition, a possible photo-catalytic degradation mechanism for the STG composite was postulated, in which~?O_2^- and~·OH were the main oxidizing groups. This work of fers new insights into a better design and preparation of novelcomposite materials for the removalof organic dyes.

关键词： String and ball-like TiO2 Reduced graphene oxide Synergistic effect Photo-catalytic Methylene blue

Novel HBD-Containing Zn (dobdc) (datz) as efficiently heterogeneous catalyst for CO_(2) chemical conversion under mild conditions

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Green Energy & Environment 2021年第1期6卷 66-74页

作者： Jianwen Lan Ye Qu ping xu Jianmin Sun State Key Laboratory of Urban Water Resource and Environment MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150080China

A novel Zn-based metal–organic framework Zn(dobdc)(datz)[Zn_(2)(H2dobdc)(datz)2$1.5DMF]with plentiful hydrogen bond donors(HBD)groups was facilely synthesized from mixed *** dual activation of metal Zn sites and HBD groups for epoxides by forming Zn–O adduct and hydrogen bonds facilitated the ring-opening of epoxide substrate,which is critical for the subsequent CO_(2) ***,the existence of micropores and N-rich units in Zn(dobdc)(datz)afforded affinity towards CO_(2),which is beneficial to further improvement on catalytic CO_(2) conversion ***,Zn(dobdc)(datz)/Bu4NBr system was proved efficient heterogeneous catalyst for the CO_(2) cycloaddition with epoxides,and 98%propylene carbonate yield was obtained under mild conditions(80C,1.5 MPa and solvent-free).In addition,Zn(dobdc)(datz)/Bu4NBr exhibited remarkable versatility to different epoxides and could be completely recycled over six runs with high catalytic *** highly stable,easily recycle and solvent-free Zn-based MOF reported here displays eco-friendly and efficient performance to CO_(2)conversion.

关键词： Heterogeneous Zn-MOF catalyst HBD groups CO_(2)conversion High versatility and recyclability Mild conditions

Hydrogen generation from methanolysis of sodium borohydride over Co/Al_2O_3 catalyst

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Journal of Natural Gas Chemistry 2012年第5期21卷 488-494页

作者： Dongyan xu Lin Zhao ping Dai Shengfu Ji College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266042ShandongChina College of Electromechanical Engineering Qingdao University of Science and TechnologyQingdao 266061ShandongChina State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China

Co/Al2O3 catalyst is prepared with an impregnation-chemical reduction method and used to catalyze the methanolysis of sodium borohydride （NaBH 4） for hydrogen *** solution temperature of 0 C,the methanolysis reaction can be effectively accelerated using Co/Al2O3 catalyst and provide a desirable hydrogen generation rate,which makes it suitable for applications under the circumstance of low environmental *** byproduct of methanolysis reaction is analyzed by X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FTIR）.The characterization results indicate that methanol can be easily recovered after methanolysis reaction by hydrolysis of the methanolysis byproduct,NaB（OCH 3） *** catalytic activity of Co/Al2O3 towards NaBH 4 methanolysis can be further improved by appropriate calcination *** catalytic methanolysis kinetics and catalyst reusability are also studied over the Co/Al2O3 catalyst calcined at the optimized temperature.

关键词： hydrogen generation sodium borohydride methanolysis cobalt

Correlation of serum albumin level on postoperative day 2 with hospital length of stay in patients undergoing emergency surgery for perforated peptic ulcer

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World Journal of Gastrointestinal Surgery 2023年第7期15卷 1434-1441页

作者： Dan Xie ping-Lan Lu Wen xu Jing-Ya you Xiao-Gang Bi Ying Xian Department of General Intensive Care Unit Lingnan HospitalThe Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhou 510530Guangdong ProvinceChina Department of Surgical Intensive Care Unit The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhou 510000Guangdong ProvinceChina

BACKGROUND Perforated peptic ulcer(PPU)is a common emergency surgical condition and a significant cause of morbidity and mortality *** advances in surgical techniques have improved outcomes for patients with PPU,many factors still affect postoperative hospital stay and overall *** potential factor is the serum albumin(SA)level,a widely utilized marker of nutritional status that has been associated with length of stay and complications in various surgical *** To clarify the correlation of SA level on postoperative day 2 with hospital length of stay(HLOS)in patients undergoing emergency surgery for perforated peptic ulcer(PPU).METHODS We retrospectively collected and analyzed clinical baseline data,including blood routine and SA levels,of patients who underwent emergency PPU surgery and postoperative treatment at the Lingnan Hospital,the Third Affiliated Hospital of Sun Yat-sen University between December 2012 and September *** were grouped according to HLOS with 7 d as the cut-off value,and relevant indicators were analyzed using SPSS *** Of the 37 patients undergoing emergency surgery for PPU referred to our department,33 had gastric and 4 had duodenal ulcer *** median HLOS was 10 *** were 8 patients in the≤7-d group(median HLOS:7 d)and 29 patients in the>7-d group(median HLOS:10 d).The≤7-d group had markedly higher SA on postoperative day 2 than the>7-d group(37.7 g/L vs 32.6g/L;P7 d(Odds ratio=0.629,P=0.015).The cut-off of SA on postoperative day 2 was 30.6g/L,with an area under the curve of 0.86 and a negative predictive value of 100%for the prediction of HLOS≤7 *** The SA level on postoperative day 2 was associated with the HLOS in patients undergoing emergency surgery for *** pre-and post-operative albumin levels should be monitored,and infusion of human SA should be considered in a timely man

关键词： Perforated peptic ulcer Emergency surgery Serum albumin Hospital length of stay

High visible light photocatalytic activities obtained by integrating g-C_(3)N_(4) with ferroelectric PbTiO_(3)

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Journal of Materials Science & Technology 2021年第15期74卷 128-135页

作者： Tingting xu ping Niu Shulan Wang Li Li Department of Chemistry School of ScienceNortheastern UniversityShenyang110819China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina School of Metallurgy Northeastern UniversityShenyang110819China

Graphitic carbon nitride(g-C_(3)N_(4))with the merits of high visible light absorption,proper electronic band structure with high conduction band edge and variable modulation,is viewed as a promising photocatalyst for practical *** alleviate its high recombination rate of photo-excited charge carriers and maximize the photocatalytic performances,it is paramount to design highly effective transfer channels for photo-excited charge *** materials can have the charge carriers transport in opposite directions owing to the internal spontaneous polarization,which may be suitable for constructing the heterostructure with g-C_(3)N_(4)for efficient charge *** by this concept,herein ferroelectric PbTiO_(3),which can be the visible-light absorber,is coupled with g-C_(3)N_(4)to construct PbTiO_(3)/g-C_(3)N_(4)heterostructure with close contact via Pb–N bond by the facile post thermal *** optimized Pb TiO_(3)/g-C_(3)N_(4)heterostructure exhibited excellent photocatalytic and photoelectrochemical activities under visible light ***,the simultaneous application of ultrasound-induced mechanical waves can further improve its photocatalytic activities through reinforcing the built-in piezoelectric *** work proposes a widely applicable strategy for the fabrication of high-performance ferroelectric based photocatalysts and also provides some new ideas for developing the understanding of ferroelectric photocatalysis.

关键词： Photocatalysis Ferroelectric Piezoelectric Carbon nitride Lead titanate

A Comprehensive Review:Recent Developments of Biomimetic Sensors

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Journal of Bionic Engineering 2022年第4期19卷 853-876页

作者： xu Ye Yuanyuan Li Yan Zhang ping Wang National Engineering Laboratory for Modern Silk College of Textile and Clothing EngineeringSoochow UniversitySuzhou 215123China

With the fast development of Internet of Things,flexible and extensible sensors have undergone a great *** of the limited functions of traditional flexible sensors,more and more researchers begin to develop biomimetic sensors inspired by nature,which introduce unique structures of various natural creatures into sensors through a simple and low-cost process,endowing them with excellent comprehensive *** imitating structures,compositions,biological mechanisms of natural organisms,these flaws can be overcome,making sensors have a variety of functions,such as hydrophobicity,discoloration and so *** this paper,biomimetic objects used in sensors are summarized from three perspectives,plants(lotus leaves),animals(butterfly wings)and components(enzymes).And then,the common preparation methods of biomimetic materials are described in detail,such as template method,hydrothermal method,***,the current applications of biomimetic sensors in wearable fields like electronic skin,human health detection and human motion detection,are also ***,the difficulties and limitations of sensors,efforts to improve properties of materials,as well as likely future developments were ***,it is highly promising to provide readers with a quick glimpse into the research landscape of this field.

关键词： Biomimetic sensors Template Lithography Wearable devices

Unsupervised pseudoinverse hashing learning model for rare astronomical object retrieval

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Science China(Technological Sciences) 2022年第6期65卷 1338-1348页

作者： WANG Ke GUO ping LUO ALi xu MingLiang Artificial Intelligence Research Center School of Computer and Artificial IntelligenceZhengzhou UniversityZhengzhou 450001China School of Systems Science Beijing Normal UniversityBeijing 100875China Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China

Searching for rare astronomical objects based on spectral data is similar to finding needles in a haystack owing to their rarity and the immense data volume gathered from large astronomical spectroscopic *** this paper,we propose a novel automated approximate nearest neighbor search method based on unsupervised hashing learning for rare spectra *** proposed method employs a multilayer neural network using autoencoders as the local compact feature *** are trained with a non-gradient learning algorithm with graph Laplace *** algorithm also simplifies the tuning of network architecture hyperparameters and the learning control ***,the graph Laplace regularization can enhance the robustness by reducing the sensibility to *** proposed model is data-driven;thus,it can be viewed as a general-purpose retrieval *** proposed model is evaluated in experiments and real-world applications where rare Otype stars and their subclass are retrieved from the dataset obtained from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(Guo Shoujing Telescope).The experimental and application results show that the proposed model outperformed the baseline methods,demonstrating the effectiveness of the proposed method in rare spectra retrieval tasks.

关键词： compact features unsupervised hashing object retrieval pseudoinverse learning

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