检索结果-南通市图书馆

Spectral properties of partially coherent chirped Airy pulsed beam in oceanic turbulence

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2021年第2期17卷 123-128页

作者： zhu bo-yuan BIAN Shao-jie TONG Yang MOU Xin-yue CHENG Ke College of Optoelectronic Technology Chengdu University of Information TechnologyChengdu 610225China

Spectral shifts and spectral intensities of partially coherent chirped Airy pulsed(PCCAP) beams propagating through oceanic turbulence are studied, where spectral properties of partially coherent chirped Gaussian pulsed(PCCGP) beams are also compared. The effects of optical parameters and oceanic turbulence parameters on spectral shifts at different observation positions are mainly discussed. It is shown that the spectral shift of PCCAP beam is richer than that of PCCGP beam, and there exists some critical positions for PCCAP beams where the spectral red-shift reaches its maximum. The spectral red-shift increases with increasing chirped parameter, correlation length or decreasing pulse duration. However, the increasing of spectral red-shift is accompanied by increasing dissipation rate of turbulence kinetic energy in unit mass liquid or decreasing relative intensity of temperature and salinity fluctuations, mean square temperature dissipation rate. A physical explanation of rapid spectral transition is also made.

关键词： turbulence coherent beam

Dynamical behavior and propagation characteristic of partially coherent sinh-Airy beams in oceanic turbulence

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2021年第1期17卷 59-64页

作者： ZHOU Yan CHENG Ke zhu bo-yuan YAO Na ZHONG Xian-qiong College of Optoelectronic Technology Chengdu University of Information TechnologyChengdu 610225China

By introducing the hyperbolic sine function to Airy beam, the dynamic behavior and propagation characteristics of partially coherent sinh-Airy beams in oceanic turbulence are studied using approximate analytical intensity expression. The influence of sinh modulation parameter, coherence length and ocean parameters on intensity evolution, beam width and kurtosis parameter is mainly discussed. The results show that a non-zero sinh modulation parameter presents not only the insensitivity to oceanic turbulence, but a smaller beam width. Furthermore, it also improves kurtosis parameter. These findings bring advantages in signal reception for long distance. In addition, a larger relative intensity of temperature or salinity fluctuations, mean square temperature dissipation rate, or a smaller dissipation rate of turbulence kinetic energy is more liable to increase beam width, or decrease intensity and kurtosis parameter of partially coherent sinh-Airy beams. The results provide an opportunity for improving signal reception of underwater communication or target detection by Airy beams or their groups.

关键词： parameter. turbulence coherent

Identification of reservoir types in deep carbonates based on mixedkernel machine learning using geophysical logging data

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第3期21卷 1632-1648页

作者： Jin-Xiong Shi Xiang-yuan Zhao Lian-bo Zeng Yun-Zhao Zhang Zheng-Ping zhu Shao-Qun Dong Key Laboratory of Exploration Technologies for Oil and Gas Resources of the Ministry of Education Yangtze UniversityWuhan4310HubeiChina School of Geosciences Yangtze UniversityWuhan430100HubeiChina College of Geosciences China University of Petroleum(Beijing)Beijing102249China Petroleum Exploration and Production Research Institute of SINOPEC Beijing100083China School of Earth Sciences and Engineering Xi'an Shiyou UniversityXi'an 710065ShaanxiChina

Identification of reservoir types in deep carbonates has always been a great challenge due to complex logging responses caused by the heterogeneous scale and distribution of storage *** cross-plot analysis and empirical formula methods for identifying reservoir types using geophysical logging data have high uncertainty and low efficiency,which cannot accurately reflect the nonlinear relationship between reservoir types and logging ***,the kernel Fisher discriminant analysis(KFD),a kernel-based machine learning technique,attracts attention in many fields because of its strong nonlinear processing ***,the overall performance of KFD model may be limited as a single kernel function cannot simultaneously extrapolate and interpolate well,especially for highly complex data *** address this issue,in this study,a mixed kernel Fisher discriminant analysis(MKFD)model was established and applied to identify reservoir types of the deep Sinian carbonates in central Sichuan Basin,*** MKFD model was trained and tested with 453 datasets from 7 coring wells,utilizing GR,CAL,DEN,AC,CNL and RT logs as input *** particle swarm optimization(PSO)was adopted for hyper-parameter optimization of MKFD *** evaluate the model performance,prediction results of MKFD were compared with those of basic-kernel based KFD,RF and SVM ***,the built MKFD model was applied in a blind well test,and a variable importance analysis was *** comparison and blind test results demonstrated that MKFD outperformed traditional KFD,RF and SVM in the identification of reservoir types,which provided higher accuracy and stronger *** MKFD can therefore be a reliable method for identifying reservoir types of deep carbonates.

关键词： Reservoir type identification Geophysical logging data Kernel Fisher discriminantanalysis Mixedkernel function Deep carbonates

Robotic versus laparoscopic surgery for sporadic benign insulinoma:Short-and long-term outcomes

在线全文

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2024年第4期23卷 399-405页

作者： zhu-Zeng Yin yuan-Xing Gao Zhi-Ming Zhao Ming-Gen Hu Wen-bo Tang Rong Liu Faculty of Hepato-Pancreato-Biliary Surgery The First Medical CenterChinese PLA General HospitalBeijing 100853China Institute of Hepatobiliary Surgery of Chinese PLA Beijing 100853China Key Laboratory of Digital Hepatobiliary Surgery of Chinese PLA Beijing 100853China

Background:Minimally invasive surgery is the optimal treatment for *** present study aimed to compare short-and long-term outcomes of laparoscopic and robotic surgery for sporadic benign ***:A retrospective analysis of patients who underwent laparoscopic or robotic surgery for insulinoma at our center between September 2007 and December 2019 was *** demographic,perioperative and postoperative follow-up results were compared between the laparoscopic and robotic ***:A total of 85 patients were enrolled,including 36 with laparoscopic approach and 49 with robotic *** was the preferred surgical ***-nine patients(69.4%)underwent enucleation;among them,26 and 33 patients underwent laparoscopic and robotic surgery,*** enucleation had a lower conversion rate to laparotomy(0 vs.19.2%,P=0.013),shorter operative time(102.0 vs.145.5 min,P=0.008)and shorter postoperative hospital stay(6.0 vs.8.5 d,P=0.002)than laparoscopic *** were no differences between the groups in terms of intraoperative blood loss,the rates of postoperative pancreatic fistula and *** a median follow-up of 65 months,two patients in the laparoscopic group developed a functional recurrence and none of the patients in the robotic group had a ***:Robotic enucleation can reduce the conversion rate to laparotomy and shorten operative time,which might lead to a reduction in postoperative hospital stay.

关键词： Robotic surgical procedures Laparoscopy Insulinoma Enucleation Pancreatectomy

Rapidly growing primordial black holes as seeds of the massive high-redshift JWST Galaxies

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第10期67卷 139-146页

作者： Guan-Wen yuan Lei Lei yuan-zhu Wang bo Wang Yi-Ying Wang Chao Chen Zhao-Qiang Shen Yi-Fu Cai Yi-Zhong Fan Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Deep Space Exploration Laboratory/Department of Astronomy School of Physical SciencesUniversity of Science and Technology of ChinaHefei 230026China Jockey Club Institute for Advanced Study The Hong Kong University of Science and TechnologyHong KongChina

A group of massive galaxies at redshifts of z■7 have been recently detected by the James Webb Space Telescope(JWST),which were unexpected to form at such an early time within the standard Big Bang *** this work,we propose that this puzzle can be explained by the presence of some primordial black holes(PBHs)with a mass of~1000M_(⊙).These PBHs act as seeds for early galaxy formation with masses of~10^(8)-10^(10)M_(⊙)at high redshift,hence accounting for the JWST *** use a hierarchical Bayesian inference framework to constrain the PBH mass distribution models,and find that the Lognormal model with the M_(c)~750M_(⊙)is preferred over other *** rapidly growing BHs are expected to have strong radiation and may appear as high-redshift compact objects,similar to those recently discovered by *** we focused on PBHs in this work,the bound on the initial mass of the seed black holes remains robust even if they were formed through astrophysical channels.

关键词： primordial black hole dark matter halo black hole accretion primordial galaxies

同方期刊数据库

Electron beam lithography on nonplanar and irregular surfaces

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2024年第2期10卷 1-23页

作者： Chenxu zhu Huseyin Ekinci Aixi Pan bo Cui Xiaoli zhu Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology(WIN) University of WaterlooWaterlooONCanada

E-beam lithography is a powerful tool for generating nanostructures and fabricating nanodevices with fine features approaching a few nanometers in ***,alternative approaches to conventional spin coating and development processes are required to optimize the lithography procedure on irregular *** this review,we summarize the state of the art in nanofabrication on irregular substrates using e-beam *** overcome these challenges,unconventional methods have been *** instance,polymeric and nonpolymeric materials can be sprayed or evaporated to form uniform layers of electron-sensitive materials on irregular ***,chemical bonds can be applied to help form polymer brushes or self-assembled monolayers on these *** addition,thermal oxides can serve as resists,as the etching rate in solution changes after e-beam ***,e-beam lithography tools can be combined with cryostages,evaporation systems,and metal deposition chambers for sample development and lift-off while maintaining low *** nanopyramids can be fabricated on an AFM tip by utilizing ice as a positive ***,Ti/Au caps can be patterned around a carbon ***,3D nanostructures can be formed on irregular surfaces by exposing layers of anisole on organic ice surfaces with a focused *** advances in e-beam lithography on irregular substrates,including uniform film coating,instrumentation improvement,and new pattern transferring method development,substantially extend its capabilities in the fabrication and application of nanoscale structures.

关键词： lithography beam coating

Gradient microstructure and superior strength-ductility synergy of AZ61 magnesium alloy bars processed by radial forging with different deformation temperatures

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第3期170卷 65-77页

作者： Jingfeng Zou Lifeng Ma Yanchun zhu Ling Qin yuan yuan School of Mechanical Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China Heavy Machinery Engineering Research Center of the Ministry Education Taiyuan University of Science and TechnologyTaiyuan 030024China Department of Engineering University of HullCottingham RdHull HU67RXUK National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China

Gradient microstructure modification is a cost-efficient strategy for high strength without compromising ductility,which is urgently needed in the fundamental science of engineering *** this study,heterogeneous structures of AZ61 alloy bars with anisotropic gradients(with different grain size distributions from the surface to the center)were observed to exhibit strong strength-ductility synergies under different deformation tem *** results reveal that the grain refinement process under mediumlow temperature deformation conditions(≤350℃)consists of four transition stages along the radial direction,i.e.,twin activations and deformation band formations,dislocation cells and pile-ups,ultrafine sub-grains,and randomly orientated quasi-micron *** deformation temperatures have a great influence on twin activations and deformation band formations,and the high temperature can easily provoke the initiation of non-basal *** deformation bands were determined as a primary nucleation site due to their highly unstable dislocation hindrance *** in combination with the Radial forging(RF)deformation process,the differences of dynamic precipitates can be attributed to microstructural difference and solubility limit of Al at different tem *** summarizing the tensile test results,the sample forged at 350℃exhibited the best strength-ductility synergy,exhibiting the highest elongation(EL)of 23.2%with a 251 MPa yield strength(YS)and 394 MPa ultimate tensile strength(UTS)in center region,and combined with the highest strength value of 256 MPa YS and 420 MPa UTS in the center region,while the EL was slightly degraded to 19.8%.

关键词： Gradient microstructure Radial forging Strength-ductility synergy Magnesium alloy Strengthening mechanism

UAV-assisted cooperative offloading energy efficiency system for mobile edge computing

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Digital Communications and Networks 2024年第1期10卷 16-24页

作者： Xue-Yong Yu Wen-Jin Niu Ye zhu Hong-bo zhu Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Nanjing210003China Engineering Research Centerof Health Service System Based on Ubiquitous Wireless Networks Ministry of EducationNanjng Universityof Posts and Telecommunications Nanjing210003China

Reliable communication and intensive computing power cannot be provided effectively by temporary hot spots in disaster areas and complex terrain ground *** this has greatly developed the application and integration of UAV and Mobile Edge Computing(MEC)to the Internet of Things(loT).However,problems such as multi-user and huge data flow in large areas,which contradict the reality that a single UAV is constrained by limited computing power,still *** to allowing UAV collaboration to accomplish complex tasks,cooperative task offloading between multiple UAVs must meet the interdependence of tasks and realize parallel processing,which reduces the computing power consumption and endurance pressure of *** the computing requirements of the user terminal,delay constraint of a computing task,energy constraint,and safe distance of UAV,we constructed a UAV-Assisted cooperative offloading energy efficiency system for mobile edge computing to minimize user terminal energy ***,the resulting optimization problem is originally nonconvex and thus,difficult to solve *** tackle this problem,we developed an energy efficiency optimization algorithm using Block Coordinate Descent(BCD)that decomposes the problem into three convex ***,we jointly optimized the number of local computing tasks,number of computing offloaded tasks,trajectories of UAV,and offloading matching relationship between multi-UAVs and multiuser *** results show that the proposed approach is suitable for different channel conditions and significantly saves the user terminal energy consumption compared with other benchmark schemes.

关键词： Computation offloading Internet of things(IoT) Mobile edge computing(MEC) Block coordinate descent(BCD)

Bifunctional two-carbon reagent made from acetylene via 1,2-difunctionalization and its applications

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第3期67卷 936-944页

作者： bo Yang Kangkui Li Yongdong Wang Shifa zhu Key Laboratory of Functional Molecular Engineering of Guangdong Province School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China School of Chemistry and Chemical Engineering Zhejiang Sci-Tech UniversityHangzhou 310018China Singfar Laboratories Guangzhou 510670China

There are very limited approaches to directly gluing two molecules for the production of internal alkenes using the vastly abundant acetylene via 1,2-difunctionalization. Conversion of gaseous acetylene to internal alkenes via 1,2-difunctionalization in a desired manner is not as easy as it might be expected due to the potential competition reactions between acetylene and alkene produced and the difficulty in handling this harmful reagent and controlling the regio-and stereoselectivity. In this work, we designed an efficient catalytic system for the incorporation of acetylene gas into tremendous(E)-β-bromo vinylsulfones, which are bench-stable, easy to operate, and can function as bifunctional acetylene and show a rich reactivity profile in Sonogashira coupling, Heck coupling, substituted reaction, and various desulfonylation transformations, providing numerous internal alkenes.

关键词： acetylene 1 2-difunctionalization photocatalysis vinylsulfone