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A Hybrid Optimization Approach of Single Point Incremental Sheet Forming of AISI 316L Stainless Steel Using Grey Relation Analysis Coupled with Principal Component Analysiss
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作者 A Visagan P Ganesh 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期160-166,共7页
We investigated the parametric optimization on incremental sheet forming of stainless steel using Grey Relational Analysis(GRA) coupled with Principal Component Analysis(PCA). AISI 316L stainless steel sheets were use... We investigated the parametric optimization on incremental sheet forming of stainless steel using Grey Relational Analysis(GRA) coupled with Principal Component Analysis(PCA). AISI 316L stainless steel sheets were used to develop double wall angle pyramid with aid of tungsten carbide tool. GRA coupled with PCA was used to plan the experiment conditions. Control factors such as Tool Diameter(TD), Step Depth(SD), Bottom Wall Angle(BWA), Feed Rate(FR) and Spindle Speed(SS) on Top Wall Angle(TWA) and Top Wall Angle Surface Roughness(TWASR) have been studied. Wall angle increases with increasing tool diameter due to large contact area between tool and workpiece. As the step depth, feed rate and spindle speed increase,TWASR decreases with increasing tool diameter. As the step depth increasing, the hydrostatic stress is raised causing severe cracks in the deformed surface. Hence it was concluded that the proposed hybrid method was suitable for optimizing the factors and response. 展开更多
关键词 single point incremental forming AISI 316L taguchi grey relation analysis principal component analysis surface roughness scanning electron microscopy
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Efficacy comparison of multipoint and single point scanning panretinal laser photocoagulation in non-proliferative diabetic retinopathy treatment
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作者 Yang-Zhou Zhang Hua Gong +2 位作者 Juan Yang Ji-Pu Bu Hui-Ling Yang 《World Journal of Diabetes》 SCIE 2024年第8期1734-1741,共8页
BACKGROUND Non-proliferative diabetic retinopathy(NPDR)poses a significant challenge in diabetes management due to its microvascular changes in the retina.Laser photocoagulation,a conventional therapy,aims to mitigate... BACKGROUND Non-proliferative diabetic retinopathy(NPDR)poses a significant challenge in diabetes management due to its microvascular changes in the retina.Laser photocoagulation,a conventional therapy,aims to mitigate the risk of progressing to proliferative diabetic retinopathy(PDR).AIM To compare the efficacy and safety of multi-spot vs single-spot scanning panretinal laser photocoagulation in NPDR patients.METHODS Forty-nine NPDR patients(86 eyes)treated between September 2020 and July 2022 were included.They were randomly allocated into single-spot(n=23,40 eyes)and multi-spot(n=26,46 eyes)groups.Treatment outcomes,including bestcorrected visual acuity(BCVA),central macular thickness(CMT),and mean threshold sensitivity,were assessed at predetermined intervals over 12 months.Adverse reactions were also recorded.RESULTS Energy levels did not significantly differ between groups(P>0.05),but the multi-spot group exhibited lower energy density(P<0.05).BCVA and CMT improvements were noted in the multi-spot group at one-month posttreatment(P<0.05).Adverse reaction incidence was similar between groups(P>0.05).CONCLUSION While energy intensity and safety were comparable between modalities,multi-spot scanning demonstrated lower energy density and showed superior short-term improvements in BCVA and CMT for NPDR patients,with reduced laser-induced damage. 展开更多
关键词 Panretinal laser photocoagulation Non-proliferative diabetic retinopathy Efficacy comparison Multipoint single point Treatment assessment
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Microfluidic-based single cell trapping using a combination of stagnation point flow and physical barrier 被引量:2
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作者 Miao Yu Zongzheng Chen +3 位作者 Cheng Xiang Bo Liu Handi Xie Kairong Qin 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2016年第3期422-429,共8页
Single cell trapping in vitro by microfluidic device is an emerging approach for the study of the relationship between single cells and their dynamic biochemical microenvironments. In this paper, a hydrodynamic-based ... Single cell trapping in vitro by microfluidic device is an emerging approach for the study of the relationship between single cells and their dynamic biochemical microenvironments. In this paper, a hydrodynamic-based microfluidic device for single cell trapping is designed using a combination of stagnation point flow and physical barrier.The microfluidic device overcomes the weakness of the traditional ones, which have been only based upon either stagnation point flows or physical barriers, and can conveniently load dynamic biochemical signals to the trapped cell. In addition, it can connect with a programmable syringe pump and a microscope to constitute an integrated experimental system.It is experimentally verified that the microfluidic system can trap single cells in vitro even under flow disturbance and conveniently load biochemical signals to the trapped cell. The designed micro-device would provide a simple yet effective experimental platform for further study of the interactions between single cells and their microenvironments. 展开更多
关键词 single cell trapping Microfluidics Stagnation point flow Physical barrier Hydrodynamic tweezers Dynamic biochemical signal
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Single Point Positioning with Sequential Least-Squares Filter and Estimated Real-Time Stochastic Model 被引量:7
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作者 WU Yun GUO Jiming 《Geo-Spatial Information Science》 2008年第1期13-16,共4页
To obtain higher accurate position estimates, the stochastic model is estimated by using residual of observations, hence, the stochastic model describes the noise and bias in measurements more realistically. By using ... To obtain higher accurate position estimates, the stochastic model is estimated by using residual of observations, hence, the stochastic model describes the noise and bias in measurements more realistically. By using GPS data and broadcast ephemeris, the numerical results indicating the accurate position estimates at sub-meter level are obtainable. 展开更多
关键词 GPS single point positioning functional model stochastic model sequential least-square filter
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Nonlinear Coupled Analysis of a Single Point Mooring System 被引量:2
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作者 WANG Junrong LI Huajun LI Ping ZHOU Kai 《Journal of Ocean University of China》 SCIE CAS 2007年第3期310-314,共5页
Coupled effects on a single point mooring(SPM) system subjected to the combined action of wind,waves and current are studied in this paper. Due to the complicatedness of the sea state and the huge size of the vessel,p... Coupled effects on a single point mooring(SPM) system subjected to the combined action of wind,waves and current are studied in this paper. Due to the complicatedness of the sea state and the huge size of the vessel,physical experimental study is both time consuming and uneconomical,whereas the numerical study is cost-effective and DNV software provides powerful SESAM software in solving the issues. This paper focuses on the modeling process of the SPM system,catenary equilibrium calculation,static analysis of the vessel in three different scenarios,and dynamic response simulation of the SPM system under environmental excitations. The three scenarios in study are as follows:the SPM is under the combined function of(a) wind,waves and current,(b) wind and waves,(c) current and waves. They are so set that one can compare the contributions of different types of loads in both static and dynamic studies. Numerical study shows that wind and current are the two major factors contributing to the mooring line tension,and surge and sway are the two dominant motions of the moored vessel subjected to environmental excitations. 展开更多
关键词 single point mooring system response amplitude operator catenary equilibrium static analysis dynamic response
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Investigation of Surface Micro Waviness in Single Point Diamond Fly Cutting 被引量:1
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作者 Sheng-Fei Wang Peng-Qiang Fu +2 位作者 Fei-Hu Zhang Chen-Hui An Yong Zhang 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2014年第5期119-123,共5页
Single point diamond fly cutting is widely used in the manufacture of large-aperture ultra-precision optical elements. However,some micro waviness( amplitude about 30 nm,wavelength about 15 mm) along the cutting direc... Single point diamond fly cutting is widely used in the manufacture of large-aperture ultra-precision optical elements. However,some micro waviness( amplitude about 30 nm,wavelength about 15 mm) along the cutting direction which will decrease the quality of the optical elements can always be found in the processed surface,and the axial vibration of the spindle caused by the cut-in process is speculated as the immediate cause of this waviness. In this paper,the analytical method of dynamic mesh is applied for simulating the dynamic behavior of the vertical spindle. The consequence is then exerted to the fly cutter and the processed surface profile is simulated. The wavelength of the simulation result coincides well with the experimental result which proves the importance of the cut-in process during the single point diamond fly cutting. 展开更多
关键词 surface waviness surface profile spindle dynamic behavior single point diamond fly cutting
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Zero-sequence Current Suppressing Strategy for Dual Three-phase Permanent Magnet Synchronous Machines Connected with Single Neutral Point 被引量:2
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作者 Zongwang Li Yuxuan Du +2 位作者 Jinghua Ji Tao Tao Wenxiang Zhao 《CES Transactions on Electrical Machines and Systems》 CSCD 2022年第4期465-472,共8页
Dual three-phase permanent-magnet synchronous machines(DTP-PMSM)connected with a single neutral point provide a loop for zero-sequence current(ZSC).This paper proposes a novel space vector pulse width modulation(SVPWM... Dual three-phase permanent-magnet synchronous machines(DTP-PMSM)connected with a single neutral point provide a loop for zero-sequence current(ZSC).This paper proposes a novel space vector pulse width modulation(SVPWM)strategy to suppress the ZSC.Five vectors are selected as basic voltage vectors in one switching period.The fundamental and harmonic planes and the zero-sequence plane are taken into consideration to synthesis the reference voltage vector.To suppress the ZSC,a non-zero zero-sequence voltage(ZSV)is generated to compensate the third harmonic back-EMF.Rather than triangular carrier modulation,the sawtooth carrier modulation strategy is used to generate asymmetric PWM signals.The modulation range is investigated to explore the variation of modulation range caused by considering the zero-sequence plane.With the proposed method,the ZSC can be considerably reduced.The simulated and experimental results are presented to validate the effectiveness of the proposed modulation strategy. 展开更多
关键词 Zero-sequence current a single neutral point dual three-phase permanent-magnet synchronous machine third harmonic back-EMF
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FIELD STUDIES OF SINGLE POINT IMPACT ON LIQUEFIABLE SOIL FOUNDATION OF HIGHWAY
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作者 沈正 刘志彬 +1 位作者 方磊 李汉光 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2013年第4期404-412,共9页
A highway in the floodplain of the Abandoned Yellow River in the north of Jiangsu Province is recently remediated to reduce liquefaction potential using the dynamic compaction(DC)method of densification of in-place so... A highway in the floodplain of the Abandoned Yellow River in the north of Jiangsu Province is recently remediated to reduce liquefaction potential using the dynamic compaction(DC)method of densification of in-place soils.Firstly,the liquefaction potential of the soil at the project site is analysed according to the code of seismic design.Then the in-situ single point impact tests are performed on the liquefiable soil.Settlement of crater,excess pore pressure,ground heave and lateral deformation under DC impact are measured and analyzed.Subsequently, the standard penetration test(SPT)and cone penetration test(CPT)are used for investigating the compaction effectiveness.At last,the improvement effect of DC is discussed according to the technical specification of dynamic consolidation to ground treatment.The investigation results indicate that the DC technique is an effective way for remediating liquefiable soil in highway engineering practice. 展开更多
关键词 dynamic compaction single point impact LIQUEFACTION standard penetration test (SPT) improvementdepth
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Microstructure and M echanical Properties of Magnesium Alloy Sheet by Friction Heating Single Point Incremental Forming
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作者 王进 王海 +1 位作者 李丽华 姜虎森 《Journal of Donghua University(English Edition)》 EI CAS 2015年第4期654-657,671,共5页
By friction heating single point incremental forming,truncated square pyramid parts with different draw angles of a magnesium alloy AZ31 B were formed at room temperature.Metallurgical,tensile and micro-hardness tests... By friction heating single point incremental forming,truncated square pyramid parts with different draw angles of a magnesium alloy AZ31 B were formed at room temperature.Metallurgical,tensile and micro-hardness tests were carried out to obtain the effects of wall angle on microstructure and mechanical properties. The results show that grain in side wall of the formed parts becomes refined significantly. Furthermore,with the increase of draw angle,grain size increases,but strength,hardness and plasticity decrease. In addition, surface roughness tests were performed on the formed surface to determine the influence of speed of forming tool. The results show that surface roughness has a little increase with the increase of tool rotational speed. 展开更多
关键词 friction heating single point incremental forming AZ31B mechanical property
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Embedded Programmable Single Point Multiple Output Intelligent Data Acquisition and Transmission System
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作者 Guoli QU Yun WU +1 位作者 Gaihua XU Lin CHEN 《Asian Agricultural Research》 2016年第11期54-60,共7页
To effectively solve the problems of inconsistent communication protocols in automatic monitoring equipment,and limited data acquisition transmission and monitoring equipment,this paper developed programmable single p... To effectively solve the problems of inconsistent communication protocols in automatic monitoring equipment,and limited data acquisition transmission and monitoring equipment,this paper developed programmable single point multiple output intelligent data acquisition and transmission system. It made an in-depth elaboration of the data acquisition and transmission system from hardware design,software architecture and principle,main functions and technical parameters. Finally,it came up with four innovation points:(i) intelligent(automatic)matching a variety of communication protocols for environmental monitoring equipment,(ii) realizing multi-protocol and multi-target parallel data transmission,(iii) realizing remote dynamic input of control instructions through wired or wireless network,and(iv) supporting configuration(process) simulation of field equipment DCS operating conditions. 展开更多
关键词 PROGRAMMABLE single point multiple output Intelligent matching multi-protocols Reverse remote control
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Point Groups and Single Forms of Quasicrystals with Eightfold and Twelvefold Symmetry
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作者 Shi Nicheng and Liao Libing Beijing Graduate School, China University of Geosiences, Beijing 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1989年第1期39-43,共5页
This paper mainly deals with the point groups and single forms of octagonal quasicrystals and the description of one-dimensional quasilattice. The authors present a new sequence for describing the arrangement of quasi... This paper mainly deals with the point groups and single forms of octagonal quasicrystals and the description of one-dimensional quasilattice. The authors present a new sequence for describing the arrangement of quasiperiods in one-dimensional quasilattice. The first ten numbers of quasiperiods of this sequence are 1, 1, 2, 5, 12, 29, 70, 169, 408 and 985. The arrangement of quasiperiods in the first five steps are a, b, ab. babab and babababbabab. Seven p(?)nt groups and nine single forms for the octagonal system have been deduced, They are as follows: Point groups: 8.8m, 82, 8/m, 8/mmm, 8 and 82m; single forms: octagonal prism, dioctagonal prism. octagonal pyramid. dioctagonal pyramid. octagonal dipyramid, dioctagonal dipyramid, octagonal scalenohedron, dioctagonal scalenohedron and octagonal trapezohedron. Besides seven point groups and nine single forms for the dodecahegonal system have also been deduced. 展开更多
关键词 point Groups and single Forms of Quasicrystals with Eightfold and Twelvefold Symmetry
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Unscented Kalman filter for a low-cost GNSS/IMU-based mobile mapping application under demanding conditions
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作者 Mokhamad Nur Cahyadi Tahiyatul Asfihani +1 位作者 Hendy Fitrian Suhandri Risa Erfianti 《Geodesy and Geodynamics》 EI CSCD 2024年第2期166-176,共11页
For the last two decades,low-cost Global Navigation Satellite System(GNSS)receivers have been used in various applications.These receivers are mini-size,less expensive than geodetic-grade receivers,and in high demand.... For the last two decades,low-cost Global Navigation Satellite System(GNSS)receivers have been used in various applications.These receivers are mini-size,less expensive than geodetic-grade receivers,and in high demand.Irrespective of these outstanding features,low-cost GNSS receivers are potentially poorer hardwares with internal signal processing,resulting in lower quality.They typically come with low-cost GNSS antenna that has lower performance than their counterparts,particularly for multipath mitigation.Therefore,this research evaluated the low-cost GNSS device performance using a high-rate kinematic survey.For this purpose,these receivers were assembled with an Inertial Measurement Unit(IMU)sensor,which actively transmited data on acceleration and orientation rate during the observation.The position and navigation parameter data were obtained from the IMU readings,even without GNSS signals via the U-blox F9R GNSS/IMU device mounted on a vehicle.This research was conducted in an area with demanding conditions,such as an open sky area,an urban environment,and a shopping mall basement,to examine the device’s performance.The data were processed by two approaches:the Single Point Positioning-IMU(SPP/IMU)and the Differential GNSS-IMU(DGNSS/IMU).The Unscented Kalman Filter(UKF)was selected as a filtering algorithm due to its excellent performance in handling nonlinear system models.The result showed that integrating GNSS/IMU in SPP processing mode could increase the accuracy in eastward and northward components up to 68.28%and 66.64%.Integration of DGNSS/IMU increased the accuracy in eastward and northward components to 93.02%and 93.03%compared to the positioning of standalone GNSS.In addition,the positioning accuracy can be improved by reducing the IMU noise using low-pass and high-pass filters.This application could still not gain the expected position accuracy under signal outage conditions. 展开更多
关键词 LoW-cost GNSS GNSS/IMU single point Positioning-IMU(SPP/IMU) Differential GNSS-IMU(DGNSS/IMU) Unscented Kalman Filter(UKF) Outageconditions
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Clinical application of acupuncture at distal single point to treatment of painful heels 被引量:1
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作者 朱现民 张敏 WANG You-jing 《World Journal of Acupuncture-Moxibustion》 2012年第4期60-64,共5页
Clinical application of acupuncture at a single point to treatment of painful heels was introduced by 5 proved cases of acupuncture at distal single point for treatment of painful heels. Acupuncture at distal single p... Clinical application of acupuncture at a single point to treatment of painful heels was introduced by 5 proved cases of acupuncture at distal single point for treatment of painful heels. Acupuncture at distal single point, such as Fēngchí (风池 GB 20), Xiàguān (下关 ST 7), Jiānqí (肩奇), Hòuxī (后溪 SI 3), Zúgēn (足跟), etc., in combination with movement of heels can rapidly and effectively alleviate pain and restore the function. Results indicated that single needling a distal point is beneficial to the freely flow of qi and blood in meridians and the manipulation promotes conduction of the needling sensation, and local movement was combined, bringing the point into the best function. This method is not only convenient, easy to manipulate, but also safe and practical, and has obvious effects, so it is worthy to be popularized. 展开更多
关键词 painful heels ACUPUNCTURE single point distal point selection
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Mechanical properties and microstructure evolution in incremental forming of AA5754 and AA6061 aluminum alloys 被引量:4
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作者 Ghulam HUSSAIN Muhammad ILYAS +1 位作者 B.B.LEMOPI ISIDORE Wasim A.KHAN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第1期51-64,共14页
This study performs single point incremental forming(SPIF)on two aluminum alloys(i.e.AA5754 and AA6061),and analyzes their post forming mechanical properties and microstructure evolution.The forming parameters namely ... This study performs single point incremental forming(SPIF)on two aluminum alloys(i.e.AA5754 and AA6061),and analyzes their post forming mechanical properties and microstructure evolution.The forming parameters namely wall angle(35°-55°),feed rate(1-4 m/min),spindle rotational speed(50-1000 r/min),and lubricant(grease and hydraulic oil)are varied to probe detailed processing effects.The pre-and post-SPIF mechanical properties and microstructures are characterized by conducting tensile tests and optical microscopy,respectively.It is shown that an increase in the wall angle,feed rate and rotational speed causes microscopic variations in the alloys such that the grains of AA5754 and the second phase particles of AA6061 elongate.As a result,the ultimate tensile strength of the formed parts is increased by 10%for AA5754 and by 8%for AA6061.And,the ductility of AA5754 is decreased from 22.9%to 12%and that of AA6061 is decreased from 16%to 10.7%.Regarding the lubricant effect,it is shown that the mechanical properties remain insensitive to the type of lubricant employed.These results indicate that SPIF processing modifies the microstructure of Al alloys in a way to enhance the strength at the cost of ductility. 展开更多
关键词 single point incremental forming mechanical properties microstructure evolution aluminum alloy wall angle forming parameter
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Finite element and experimental analyses of cylindrical hole flanging in incremental forming 被引量:3
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作者 G.HUSSAIN H.VALAEI +1 位作者 Khalid A.Al-GHAMDI B.KHAN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第9期2419-2425,共7页
The influence of the size of pre-cut hole of blank on the formability of cylindrical hole flanging in single point incremental forming(SPIF) was studied. The flange is produced in four stages starting from 45° ... The influence of the size of pre-cut hole of blank on the formability of cylindrical hole flanging in single point incremental forming(SPIF) was studied. The flange is produced in four stages starting from 45° to 90° and employing aluminum as the test material. It is shown that the hole size has significant effects on the stress/strain distribution on the cylindrical flange. The magnitude of hoop strains increases and the flange thickness increases as the hole size increases. Likewise, the von Mises stress reduces with the increasing of hole size. Further, there is a threshold value of hole size(i.e., 80 mm) below which severe stresses occur, which lead to sheet fracturing thus failing the successful forming of cylindrical flange. Moreover, the formability reduces as the hole size is increased above the threshold size. Finally, it is concluded that 80 mm is the threshold size of hole for maximizing the formability of aluminum sheet in incremental hole flanging. 展开更多
关键词 hole flanging single point incremental forming(SPIF) FORMABILITY stress STRAIN THRESHOLD
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Single point and asymmetric incremental forming 被引量:2
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作者 J. Jeswiet D. Adams +2 位作者 M. Doolan T. McAnulty P. Gupta 《Advances in Manufacturing》 SCIE CAS CSCD 2015年第4期253-262,共10页
This paper presents an update on single point incremental forming (SPIF) of sheet metal since 2005. It includes a description of the process with new information on the maximum forming angle, Фmax, for 5052-H32. An... This paper presents an update on single point incremental forming (SPIF) of sheet metal since 2005. It includes a description of the process with new information on the maximum forming angle, Фmax, for 5052-H32. An indepth example of the successful design and production of parts is given for industry. This includes discussion on production times and surface roughness with details that will help designers. A general design guide for users of SPIF is provided. It is based upon experience gained in the last decade. In general, materials show a trend of decreasing formability with increasing initial thickness. It is shown that for thicker sheet metal, it is recommended using large spherical tools (12.7 mm or larger), or a large fiat-ended tool. The fiat-ended tool provides the best combination of good formability and very low surface roughness. For aluminum, galvanized steel and stainless steel, it is recommended using a fiat-ended tool. Advances in multi-pass techniques and information on successful and useful numerical models which predict forming behaviour are included. Finally, there is a discussion on future work needed in SPIF. 展开更多
关键词 single point incremental forming (SPIF) Design guide for SPIF Advances in SPIF
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Dynamic Analysis for the Global Performance of An SPM-Feeder-Cage System Under Waves and Currents 被引量:2
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作者 Cristian CIFUENTES M.H.KIM 《China Ocean Engineering》 SCIE EI CSCD 2015年第3期415-430,共16页
In the present study, the dynamic response of a coupled SPM-feeder-cage system under irregular waves and shear currents is analyzed. A numerical model is developed by using the commercial software Orca Flex. Hydrodyna... In the present study, the dynamic response of a coupled SPM-feeder-cage system under irregular waves and shear currents is analyzed. A numerical model is developed by using the commercial software Orca Flex. Hydrodynamics coefficients of the vessel are calculated by using a 3D diffraction/radiation panel program. First- and second-order wave forces are included in the calculations. Morison equation is used to compute the drag force on line elements representing the net. Drag coefficients are determined at every time step in the simulation considering the relative normal velocity between the structural elements and the fluid flow. The dynamic response of the coupled system is analyzed for various environments and net materials. The results of the study show the effects of solidity ratio of the net and vertical positions of the cage on the overall dynamic response of the system, confirming the viability of this type of configuration for future development of offshore aquaculture in deep waters. 展开更多
关键词 offshore aquaculture SPM(single point mooring) feeder vessel connecting lines operational/survival environment drag force equivalent net cage grouping net modeling line tensions solidity ratio
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Investigation of Internal Turret Mooring System for Oil Production Storage Vessels
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作者 Ma Zhiliang , Huang Xianglu , Ma Peisun Fan Genfa, Yu Xiangsan and Jin Dexian Professor, Shanghai Jiao Tong University, Shanghai Associate Professor, Shanghai Jiao Tong University, Shanghai Research Fellow, Shanghai Jiao Tong University, Shanghai 《China Ocean Engineering》 SCIE EI 1991年第4期395-408,共14页
The internal turret mooring system for oil production storage vessels is a developing type ofoffshore floating production system suitable for deep water and harsh environmental application. In this paper, some achieve... The internal turret mooring system for oil production storage vessels is a developing type ofoffshore floating production system suitable for deep water and harsh environmental application. In this paper, some achievements in our research work are presented. The description includes: dynamic analysis of mooring system, research on performance of turret assembly, influence of vessel dimensions and hull forms on mooring performance, model tests under combined action of environmental forces in basin, and hull structural strength analysis. 展开更多
关键词 floating production system single point mooring turrent mooring system oil production storage vessel production storage unit
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Attention-Based Multi-Scale Prediction Network for Time-Series Data
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作者 Junjie Li Lin Zhu +2 位作者 Yong Zhang Da Guo Xingwen Xia 《China Communications》 SCIE CSCD 2022年第5期286-301,共16页
Time series data is a kind of data accumulated over time,which can describe the change of phenomenon.This kind of data reflects the degree of change of a certain thing or phenomenon.The existing technologies such as L... Time series data is a kind of data accumulated over time,which can describe the change of phenomenon.This kind of data reflects the degree of change of a certain thing or phenomenon.The existing technologies such as LSTM and ARIMA are better than convolutional neural network in time series prediction,but they are not enough to mine the periodicity of data.In this article,we perform periodic analysis on two types of time series data,select time metrics with high periodic characteristics,and propose a multi-scale prediction model based on the attention mechanism for the periodic trend of the data.A loss calculation method for traffic time series characteristics is proposed as well.Multiple experiments have been conducted on actual data sets.The experiments show that the method proposed in this paper has better performance than commonly used traffic prediction methods(ARIMA,LSTM,etc.)and 3%-5%increase on MAPE. 展开更多
关键词 network traffic prediction attention mechanism neural network machine learning single point forecast
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Some Polar Sets for the Generalized Brownian Sheet
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作者 LI Huiqiong LIU Luqin CHEN Zhenlong 《Wuhan University Journal of Natural Sciences》 CAS 2008年第2期137-140,共4页
Let W^-(t)(t∈R+^N) be the d-dimensional N-parameter generalized Brownian sheet. We study the polar sets for W^-(t). It is proved that for any α∈ R^d, P{W^-(t) = α, for some t∈ R〉^N} = {1, if βd 〈 2N ... Let W^-(t)(t∈R+^N) be the d-dimensional N-parameter generalized Brownian sheet. We study the polar sets for W^-(t). It is proved that for any α∈ R^d, P{W^-(t) = α, for some t∈ R〉^N} = {1, if βd 〈 2N ,0 if αd〉 2N and the probability that W^-(t) has k-multiple points is 1 or 0 according as whether 2kN〉d(k-1)β or 2kN 〈 d(k - 1)α. These results contain and extend the results of the Brownian sheet, where R〉^N = (0,+∞)U,R+^N = [0,+∞)^N,0〈 α ≤1and β〉1. 展开更多
关键词 generalized Brownian sheet polar set single point multiple points
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