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Multi-state autonomous drilling for lunar exploration

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Chinese Journal of Aeronautics 2016年第5期29卷 1397-1404页

作者： Chen Chongbin quan Qiquan shi Xiaomeng Deng Zongquan Tang Dewei Jiang Shengyuan State Key Laboratory of Robotics and System Harbin Institute of Technology

Due to the lack of information of subsurface lunar regolith stratification which varies along depth, the drilling device may encounter lunar soil and lunar rock randomly in the drilling process. To meet the load safety requirements of unmanned sampling mission under limited orbital resources, the control strategy of autonomous drilling should adapt to the indeterminable lunar environments. Based on the analysis of two types of typical drilling media （i.e., lunar soil and lunar rock）, this paper proposes a multi-state control strategy for autonomous lunar drilling. To represent the working circumstances in the lunar subsurface and reduce the complexity of the control algo- rithm, lunar drilling process was categorized into three drilling states： the interface detection, initi- ation of drilling parameters for recognition and drilling medium recognition. Support vector machine （SVM） and continuous wavelet transform were employed for the online recognition of drilling media and interface, respectively. Finite state machine was utilized to control the transition among different drilling states. To verify the effectiveness of the multi-state control strategy, drilling experiments were implemented with multi-layered drilling media constructed by lunar soil simulant and lunar rock simulant. The results reveal that the multi-state control method is capable of detecting drilling state variation and adjusting drilling parameters timely under vibration interferences. The multi-state control method provides a feasible reference for the control of extraterrestrial autonomous drilling.

关键词： Finite state machine Recognition algorithm Simulants Support vector machine Wavelet transform

Xanthium Suppression Under Maize||Sunflower Intercropping System

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Journal of Integrative Agriculture 2012年第6期11卷 1026-1037页

作者： CHEN Yuan-quan SUI Peng LUAN Chen shi Xue-peng College of Agronomy and Biotechnology China Agricultural UniversityBeijing 100193P.R.China

Weed control is one of the major constraint factors in crop production around the world. Field experiments were conducted during 2008-2009 under intercropping systems involving alfalfa （Medicago sativa L.）, sweet potato （lpomoea batatas [L.] Lain.）, peanut （Arachis hypogaea L.）, and sunflower （Helianthus annuus L.） in maize （Zea mays L.） without any weeds control methods taken. The results demonstrate that maizellsunflower is most effective on weed suppression and that it also has a more competitively inhibitory effect on Xanthium compared with the other patterns by evaluating the Xanthium density and dry weight under different intercropping systems with maize. Maizellpeanut, maizellalfalfa and maizel]sweet potato intercrops have no apparent inhibitory effect on weeds. To further investigate the effect of maize]lsunflower on weed control, indoor pot experiments were conducted by determining the effect of extractions on germination rate （GR）, root vigor, MDA （malondialdehyde）, SOD （superoxide dismutase） and POD （peroxidase） content of Xanthium. The results better prove that maizellsunflower extractions have more significant inhibitory effect on GR and young root vigor of Xanthium than maize monocrop extractions.

关键词： maize sunflower Xanthium intercropping weed suppression

Secure Bipartite Tracking Control for Linear Leader-Following Multiagent Systems Under Denial-of-Service Attacks

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IEEE/CAA Journal of Automatica Sinica 2022年第8期9卷 1512-1515页

作者： Lulu Chen Lei shi quan Zhou Hanmin Sheng Yuhua Cheng School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu 611731China China Railway Rolling Stock Corporation QINGDAO SIFANG CO.LTD.Qingdao 266311

Dear editor,This letter puts forward a secure feedback control scheme to bipartite tracking consensus for a set of generic linear autonomous agents subject to aperiodic and unknown denial-of-service(Do S)attacks.

关键词： bipartite letter autonomous

Boundary Perturbed Problem for Reaction Diffusion Time Delay Equation with Two Parameters

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Wuhan University Journal of Natural Sciences 2015年第2期20卷 93-96页

作者： XU Yonghong shi Lanfang mo Jiaqi Department of Mathematics and Physics Bengbu College College of Mathematics and Statistics Nanjing University of Information Science and Technology Department of Mathematics Anhui Normal University

The singular perturbation problem for reaction diffusion time delay equation with boundary perturbation is considered. Firstly, the outer solution for the initial boundary value problem is constructed. Then, the initial and boundary layer correction terms are obtained using the stretched variables transforms. Finally, the asymptotic behavior of solution for the initial boundary value problem is studied.

关键词： nonlinear reaction diffusion asymptotic solution

High-Porosity Foam-Based Iontronic Pressure Sensor with Superhigh Sensitivity of 9280 kPa^(-1)

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Nano-Micro Letters 2022年第2期14卷 12-23页

作者： Qingxian Liu Yuan Liu Junli shi Zhiguang Liu quan Wang Chuan Fei Guo School of Astronautics Harbin Institute of TechnologyHarbin 150001HeilongjiangPeople’s Republic of China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055People’s Republic of China Department of Mechanics and Aerospace Engineering Southern University of Science and TechnologyShenzhen 518055GuangdongPeople’s Republic of China Department of Civil and Environmental Engineering Shantou UniversityShantou 515063GuangdongPeople’s Republic of China Department of Mechanical Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA Department of Physics and TcSUH University of HoustonHoustonTX 77204USA Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices Southern University of Science and TechnologyShenzhen 518055GuangdongPeople’s Republic of China Present Address:320 Crescent Village Circle Unit 1413 San JoseCA 95134USA

Flexible pressure sensors with high sensitivity are desired in the fields of electronic skins,human-machine interfaces,and health *** ionic soft materials with microstructured architectures in the functional layer is an effective way that can enhance the amplitude of capacitance signal due to generated electron double layer and thus improve the sensitivity of capacitive-type pressure ***,the requirement of specific apparatus and the complex fabrication process to build such microstructures lead to high cost and low ***,we report a simple strategy that uses open-cell polyurethane foams with high porosity as a continuous three-dimensional network skeleton to load with ionic liquid in a one-step soak process,serving as the ionic layer in iontronic pressure *** high porosity(95.4%) of PU-IL composite foam shows a pretty low Young's modulus of 3.4 kPa and good compressibility.A superhigh maximum sensitivity of 9,280 kPa^(-1) in the pressure regime and a high pressure resolution of 0.125% are observed in this foam-based pressure *** device also exhibits remarkable mechanical stability over 5,000 compression-release or bending-release *** high porosity of composite structure provides a simple,cost-effective and scalable way to fabricate super sensitive pressure sensor,which has prominent capability in applications of water wave detection,underwater vibration sensing,and mechanical fault monitoring.

关键词： High porosity Elastic modulus Compression deformation Iontronic pressure sensor Superhigh sensitivity

Multi-track Storage of 10000 Holograms in a Disk-Type Photorefractive Crystal

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Chinese Physics Letters 2000年第9期17卷 675-677页

作者： TAO shi-quan XU Min LIU Guo-Qing YUAN quan JIANG Zhu-qing Applied Physics Department Beijing Polytechnic UniversityBeijing 100022

Three-dimensional disk-type holographic storage using spatioangular multiplexing with a spherical reference beam is analyzed and experimentally *** overlapping factors between adjacent holograms in a track and between adjacent tracks in a disk are determined based on the selective angles calculated by coupled-wave *** are 10000 holograms stored along 5 tracks in a sector of a single iron-doped lithium niobate crystal.

关键词： theory. holographic lithium

Lateral Bearing Capacity of modified Suction Caissons Determined by Using the Limit Equilibrium Method

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China Ocean Engineering 2018年第4期32卷 461-466页

作者： LI Da-yong MA shi-li ZHANG Yu-kun CHEN Fu-quan College of Civil Engineering Fuzhou University Key Laboratory of Civil Engineering Disaster Prevention and Mitigation Shandong University of Science and Technology

The modified suction caisson(MSC) adds a short-skirted structure around the regular suction caissons to increase the lateral bearing capacity and limit the deflection. The MSC is suitable for acting as the offshore wind turbine foundation subjected to larger lateral loads compared with the imposed vertical loads. Determination of the lateral bearing capacity is a key issue for the MSC design. The formula estimating the lateral bearing capacity of the MSC was proposed in terms of the limit equilibrium method and was verified by the test results. Parametric studies on the lateral bearing capacity were also carried out. It was found that the lateral bearing capacity of the MSC increases with the increasing length and radius of the external skirt, and the lateral bearing capacity increases linearly with the increasing coefficient of subgrade reaction. The maximum lateral bearing capacity of the MSC is attained when the ratio of the radii of the internal compartment to the external skirt equals 0.82 and the ratio of the lengths of the external skirt to the internal compartment equals 0.48, provided that the steel usage of the MSC is kept constant.

关键词： modified suction caissons(MSCs) lateral bearing capacity limit equilibrium method parametric studies

Clinical features and prognostic factors of duodenal neuroendocrine tumours:A comparative study of ampullary and nonampullary regions

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 907-918页

作者： Sa Fang Yu-Peng shi Lu Wang Shuang Han Yong-quan shi Department of Gastroenterology Honghui HospitalXi’an Jiaotong UniversityXi'an 710054Shanxi ProvinceChina Department of Gastroenterology The Second Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710032Shaanxi ProvinceChina Department of Gastroenterology Xijing Hospital Affiliated to Air Force Medical UniversityXi'an 710032Shaanxi ProvinceChina

BACKGROUND Duodenal neuroendocrine tumours(DNETs)are rare ***,the incidence of DNETs has been increasing in recent years,especially as an incidental finding during endoscopic ***,there is no consensus regarding the ideal treatment of *** there are few studies on the clinical features and survival analysis of *** To analyze the clinical characteristics and prognostic factors of patients with duodenal neuroendocrine *** The clinical data of DNETs diagnosed in the First Affiliated Hospital of Air Force Military Medical University from June 2011 to July 2022 were ***-docrine tumours located in the ampulla area of the duodenum were divided into the ampullary region group;neuroendocrine tumours in any part of the duo-denum outside the ampullary area were divided into the nonampullary region *** a retrospective study,the clinical characteristics of the two groups and risk factors affecting the survival of DNET patients were *** Twenty-nine DNET patients were *** male to female ratio was 1:1.9,and females comprised the *** ampullary region group accounted for 24.1%(7/29),while the nonampullary region group accounted for 75.9%(22/29).When diagnosed,the clinical symptoms of the ampullary region group were mainly abdominal pain(85.7%),while those of the nonampullary region groups were mainly abdominal distension(59.1%).There were differences in the composition of staging of tumours between the two groups(Fisher's exact probability method,P=0.001),with nonampullary stage II tumours(68.2%)being the main stage(P<0.05).After the diagnosis of DNETs,the survival rate of the ampullary region group was 14.3%(1/7),which was lower than that of 72.7%(16/22)in the nonampullary region group(Fisher's exact probability method,P=0.011).The survival time of the ampullary region group was shorter than that of the nonampullary region group(P<0.000).The median survival time of the ampullary

关键词： Duodenum Neuroendocrine Tumour Ampullary Nonampullary Clinical features Prognostic

Acoustic radiation force on thin elastic shells in liquid

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Chinese Physics B 2020年第9期29卷 337-342页

作者： Run-Yang mo Jing Hu shi Chen Cheng-Hui Wang Shaanxi Key Laboratory of Ultrasonics School of Physics and Information TechnologyShaanxi Normal UniversityXi'an 710119China

Based on the coupled acoustic scattering of two neighboring fluid-filled thin elastic shells suspending in an unbounded viscous liquid,an analytical method is developed to calculate the acoustic radiation force(ARF)of the *** physical effects are taken into account:elastic radiation scattering and the multiple interactions of *** results reveal that the magnitude of ARF can be enhanced by the sound radiation from the elastic shell undergoing forced vibrations and two resonant peaks can be observed on the ARF function *** feature of the lower peak is determined by the interactions and acoustic response of the back *** attractive forces can be obtained in the low kR1 band for the case of radius ratio R2/R1>1,while the magnitude of ARF at the lower peak may be influenced to some extent by acoustic shielding phenomenon for the case of radius ratio R2/R1<***,the interactions of particles cannot be *** results may provide a theoretical basis for precisive manipulation of multiple particle systems.

关键词： thin elastic shell radiation force elastic radiation scattering mutual interactions