检索结果-南通市图书馆

Hybrid Diffuse and Sharp Interface Immersed Boundary Methods for Particulate Flows in the Presence of Complex Boundaries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2022年第4期31卷 1242-1271页

作者： Jianhua Qin Xiaolei Yang zhaobin li The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

A coupling framework that leverages the advantages of the diffuse and sharp interface immersed boundary(IB)methods is presented for handling the interaction among particles and particles with the static complex geometries of the *** the proposed coupling approach,the curvilinear IB method is employed to represent the static complex geometries,a variant of the direct forcing IB method is proposed for simulating particles,and the discrete element method is employed for particle-particle and particle-wall *** proposed approach is validated using several classical benchmark problems,which include flow around a sphere,sedimentation of a sphere,collision of two sedimenting spheres,and collision between a particle and a flat wall,with the present predictions showing an overall good agreement with the results reported in the *** capability of the proposed framework is further demonstrated by simulating the interaction between multiple particles and a wall-mounted cylinder,and the particle-laden turbulent flow over periodic *** proposed method provides an efficient way to simulate particle-laden turbulent flows in environments with complex boundaries.

关键词： Immersed boundary method particle-laden flow complex geometry

The role of high-energy computed radiography(CR)in radiotherapy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2009年第1期20卷 31-36页

作者： li zhaobin SUN Yi LU Yaohong FU Shen Department of Radiation Oncology the No.6 Hospital of Shanghai JiaoTong University Shanghai 200233 China

Computed radiography(CR)imaging has high irradiation tolerance and it is easy to archive CR images along with other image information by Digital Imaging and Communications in Medicine(DICOM)format,and to process *** can be used in radiation Quality Control(QC)task and verification of treatment *** this paper,the role of high-energy CR in radiation oncology is *** patients were imaged by CR system and EPID before *** verification images were acquired with 1–2 MU(Monitor Unit)using 6 MV *** for a linac was done with film and high-energy CR to collect the data on daily,weekly and monthly *** QC included Multileaf Collimators(MLC)calibration and mechanical iso-centre *** was also adapted to verify patient position,the film was used to compare with digitally reconstructed radiographs(DRR)and portal image from EPID. Treatment setting-up was verified based on the result of *** quality verification images could be acquired by the CR *** to EPID,the results showed that the system was suitable for practical use to acquire daily verification images,and it was useful to fulfill part of quality assurance(QA)in radiation *** quality of image acquired by the high-energy CR system is comparable or even better than DRRs and portal images. The final treatment set-up for the patients could be verified more accurately with the CR system.

关键词：计算机X摄影方法影像效果图像融合医学应用

Towards multi-fidelity simulation of flows around an underwater vehicle with appendages and propeller

在线全文

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2022年第1期12卷 35-41页

作者： Zhideng Zhou zhaobin li Guowei He Xiaolei Yang The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

Flow around a real-life underwater vehicle often happens at a high Reynolds number with flow structures at different scales from the boundary layer around a blade to that around the hull. This poses a great challenge for large-eddy simulation of an underwater vehicle aiming at resolving all relevant flow scales. In this work, we propose to model the hull with appendages using the immersed boundary method, and model the propeller using the actuator disk model without resolving the geometry of the blade. The proposed method is then applied to simulate the flow around Defense Advanced Research Projects Agency(DARPA) suboff. An overall acceptable agreement is obtained for the pressure and friction coefficients. Complex flow features are observed in the near wake of suboff. In the far wake, the core region is featured by a jet because of the actuator disk, surrounded by an annular region with velocity deficit due to the body of suboff.

关键词： Multi-fidelity model Large-eddy simulation Immersed boundary method Actuator disk model DARPA suboff

A preliminary clinic dosimetry study for synchrotron radiation therapy at SSRF

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2013年第6期24卷 7-11页

作者： li zhaobin SHI Zeliang ZHANG Qing WANG Yong FU Shen The 6th People's Hospital of Shanghai Jiaotong University

Synchrotron radiation(SR)represents a unique and innovative anti-cancer treatment due to its unique physical features,including high flux density,and tunable and collimated radiation *** aim of this work is to assess the dosimetric properties of SR in Shanghai Synchrotron Radiation Facility(SSRF)for potential applications to clinical radiation *** experiments were performed with 34 and 50 keV X-rays on the BL13W biomedical beamline of SSRF and the 6 MV X-rays from ARTISTE linac for the dosimetry *** percentage depth dose(PDD)and the surface dose of the SR X-rays and the 6 MV photon beams were performed in solid water phantom with Gafchromic EBT3 *** curves are normalized to the maximum calculated *** depth of full dose buildup is about 10μm deeper for the monoenergetic X-ray beams of 34 and 50 *** beam transmits through the phantom,with a linear attenuation *** profile in the horizontal plane shows that the dose distribution is uniform within the facula,while the vertical profile shows a Gaussian distribution of the *** penumbra is less than 0.2 mm in the horizontal *** EBT film may be a useful and convenient tool for dose measurement and quality control for the high space and density *** is therefore important to gain a thorough understanding about the physical features of SR before this novel technology can be applied to clinical practice.

关键词：上海同步辐射装置剂量学特性辐射治疗临床实践光源 SSRF X射线束线性衰减系数

How far the wake of a wind farm can persist for?

在线全文

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2022年第1期12卷 17-22页

作者： Guodan Dong zhaobin li Jianhua Qin Xiaolei Yang The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

With the increased penetration of wind energy in our nation’s energy portfolio, wind farms are placed in a way close to each other. Thus, their wakes have to be fully considered in the design and operation of a wind farm. In this study, we investigate the wake of a wind farm using large-eddy simulation with wind turbine rotor modelled by the actuator disk model. The simulated results show that the wake of a wind farm can persist for a long distance in its downstream. For the considered wind farm layout, the velocity in the wake recovers 95% of that of the undisturbed inflow at 55 rotor diameters downstream from its last row, suggesting that the wake of a wind farm should be fully considered in the optimal design and operation for its downstream wind farms.

关键词： Wind farm wake Large-eddy simulation Actuator disk Wind turbine wake

A Safe and Reliable Routing Mechanism of LEO Satellite Based on SDN

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2020年第7期64卷 439-454页

作者： Chao Guo Juan Guo Chanjuan Yu zhaobin li Cheng Gong Abdul Waheed Department of Electronics and Communication Engineering Beijing Electronic Science and Technology InstituteBeijing100070China Vocational and Technical College Guilin University of Electronic TechnologyBeihai536000China School of Computer and Communication Engineering University of Science and Technology BeijingBeijing100083China University of Management Technology Lahore55300Pakistan

Satellite networks have high requirements for security and data processing *** order to improve the reliability of the network,software-defined network(SDN)technology is introduced and a central controller is set in the *** to the characteristics of global perspective,control data separation,and centralized control of SDN,the idea of SDN is introduced to the design of the satellite network *** a result,satellite nodes are only responsible for data transmission,while the maintenance of the links and the calculation of routes are implemented by the *** the massive LEO satellite network based on SDN,a state evaluation decision routing mechanism is *** designed mechanism monitors the status of the entire network effectively and reduces the on-board load on the satellite *** best routing decision is made under the comprehensive consideration of the current and historical status of each inter-satellite link between Low Earth Orbit(LEO)satellite network *** calculation and storage requirements are controlled within a reasonable *** on the curve parameter transmission fuzzy encryption algorithm,a safe and reliable condition assessment decision routing mechanism(CADRM)is *** ensures that the personal information of the LEO satellite network can be transmitted safely and *** experimental simulation results show the improvement of network throughput,the reduction of packet loss rate and the enhancing of network reliability.

关键词： Route LEO satellite SDN state assessment inter-satellite link

The role of AGFA high-energy CR in the calibration and quality con-trol of multileaf collimators(MLC)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2007年第3期18卷 145-149页

作者： li zhaobin XIONG Fei HUANG Guofeng CAO Zheng JIANG Ruiyao FU Shen Department of Radiation Oncology the No.6 Hospital of Shanghai Jiaotong University Shanghai 200233 China

linear accelerators equipped with multileaf collimators (MLC) are becoming more common and are widely used in the intensity-modulated radiotherapy (IMRT). There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance (QA) and quality control (QC). This paper is aimed to investigate the role of AGFA high-energy CR (Computed Radiography) in calibrating dynamic multileaf col- limators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required.

关键词：高能量CR MLC校准质量控制放射疗法

在线全文

学校读者我要写书评

暂无评论

算力网络应用平台研究与设计

信息技术与信息化 2024年第2期 27-30页

作者：许俊东李兆滨宋德华田韧浪潮通信信息系统有限公司山东济南250101

针对算力网络(CPN)因算力多样泛在、多要素融合、需求差异化的特点导致的用户使用困难、应用管理难等问题,从纳管与接入、决策与调度、应用与开放三个层面研究算力网络应用的管理以及异构算力融合和跨域编排关键技术,并设计一个算力网... 详细信息

针对算力网络(CPN)因算力多样泛在、多要素融合、需求差异化的特点导致的用户使用困难、应用管理难等问题,从纳管与接入、决策与调度、应用与开放三个层面研究算力网络应用的管理以及异构算力融合和跨域编排关键技术,并设计一个算力网络应用平台。通过提供一种即开即用、按需付费的零感知算网应用服务,使用户关注于应用服务需求,无需关心算力资源需求和算力网络复杂环境,从而实现降低用户的算力网络使用门槛,提升算网应用的使用和管理效率的目标。

关键词：算力网络应用平台零感知算网应用服务应用管理异构算力融合跨域算力编排

The Impact of High-standard Free Trade Areas on the Diversification of China's Export Products: Expanding Market or Intensifying Competition?

在线全文

学校读者我要写书评

暂无评论

China & World Economy 2024年第4期32卷 33-67页

作者： zhaobin Fan Ruimin Bian Hui li International Business School Jinan UniversityChina School of Management Jinan UniversityChina School of Mathematics University of BirminghamUK

In the context of China's efforts to establish a global network of free trade areas and diversify its export products, this study explores the impact of trade agreement depth on China's export diversification. Building upon a trade model with multiproduct firms, we discover that the effect of trade agreement depth on export diversification is multifaceted, depending on the relative magnitude of the “market expansion effect” and the “competition intensification effect.” Through empirical analysis of China's exports to 132 countries (or regions) from 2000 to 2015, we find that the deepening of trade agreements affected China's export diversification negatively. This negative correlation was predominantly due to the similarity in comparative advantages between China and its trade partners, leading to the “competition intensification effect” overshadowing the “market expansion effect.” We also note that “natural” agreements, when deepened, were more likely to affect China's export diversification adversely than their “non-natural” counterparts. Moreover, as export diversification increased, the marginal impact of deepening trade agreements exhibited an inverted U-shaped trajectory.

关键词： export product diversification export similarity high-standard free trad areas trade agreement depth