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Aperture shape optimization in intensity-modulated radiation therapy planning

Nuclear Science and Techniques 2023年第9期34卷 106-117页

作者： Li-Yuan zhang Zhi-Guo Gui peng-cheng zhang Jie Yang Shanxi Provincial Key Laboratory for Biomedical Imaging and Big Data North University of ChinaTaiyuan 030051China School of Medicine Management Shanxi University of Chinese MedicineTaiyuan 030619China

The gradient element of the aperture gradient map is utilized directly to generate the aperture shape without *** process can be likened to choosing the direction of negative gradient descent for the generic aperture shape *** negative gradient descent direction is more suitable under local conditions and has a slow convergence *** overcome these limitations,this study introduced conjugate gradients into aperture shape optimization based on gradient ***,the aperture gradient map of the current beam was obtained for the proposed aperture shape optimiza-tion method,and the gradients of the aperture gradient map were modulated using conjugate gradients to form a modulated gradient *** aperture shape was generated based on the modulated gradient *** proposed optimization method does not change the optimal solution of the original optimization problem,but changes the iterative search direction when generating the aperture *** performance of the proposed method was verified using cases of head and neck cancer,and prostate *** optimization results indicate that the proposed optimization method better protects the organs at risk and rapidly reduces the objective function value by ensuring a similar dose distribution to the planning target *** to the contrasting methods,the normal tissue complication probability obtained by the proposed optimization method decreased by up to 4.61%,and the optimization time of the proposed method decreased by 5.26%on average for ten cancer *** effectiveness and acceleration of the proposed method were verified through comparative *** to the comparative experiments,the results indicate that the proposed optimization method is more suitable for clinical *** is feasible for the aperture shape optimization involving the proposed method.

关键词： Aperture shape Column generation Conjugate gradient Gradient modulation Direct aperture optimization

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Tensile deformation behavior of nickel-free high-manganese austenitic cryogenic-temperature steel

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Journal of Iron and Steel Research(International) 2022年第5期29卷 793-801页

作者： Xin-tian Wang Hui-bin Wu Yang Gu Li-xiong Xu peng-cheng zhang Qi-bo Tang National Center for Materials Service Safety University of Science and Technology BeijingBeijing100083China Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing100083China

Nickel-free high-manganese austenitic Fe–24.4Mn–4.04Al–0.057C steel was produced by smelting,and the homogenized forged billet was *** plastic deformation mechanism was investigated through tensile testing of the hot-rolled *** characterization techniques such as scanning electron microscopy,transmission electron microscopy,electron backscattered diffraction,and X-ray diffraction were used to analyze the microstructural evolution of steel under different strain *** steel had a single austenite phase,which was stable during *** hot rolling,annealing twins were observed in the microstructure of the *** steel showed an excellent combination of mechanical properties,like a tensile strength of 527 MPa,impact energy of 203 J at−196℃,and an elongation of 67%till *** the initial deformation stage,the dislocations were generated within the austenite grains,entangled and accumulated at the grain boundaries and annealing twin *** twins participated in plastic deformation and hindered the dislocation *** the deformation progressed,the dislocation slip was hindered and produced stress concentration,and the stacking faults evolved into mechanical twins,which released the stress concentration and delayed the necking.

关键词： High-manganese steel Austenite grain Tensile deformation Mechanical twin Annealing twin

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Multi-objective optimization and evaluation of supercritical CO_(2) Brayton cycle for nuclear power generation

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Nuclear Science and Techniques 2024年第2期35卷 183-209页

作者： Guo-peng Yu Yong-Feng cheng Na zhang Ping-Jian Ming Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China School of Civil Engineering and Architecture East China Jiaotong UniversityNanchang 330013China

The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle *** models of four Brayton cycle layouts are developed in this study for different reactors to reduce the cost and increase the thermohydraulic performance of nuclear power generation to promote the commercialization of nuclear *** analysis,multi-objective optimizations,and four decision-making methods are applied to obtain each Brayton scheme’s optimal thermohydraulic and economic *** show that for the same design thermal power scale of reactors,the higher the core’s exit temperature,the better the Brayton cycle’s thermo-economic *** the four-cycle layouts,the recompression cycle(RC)has the best overall performance,followed by the simple recuperation cycle(SR)and the intercooling cycle(IC),and the worst is the reheating cycle(RH).However,RH has the lowest total cost of investment(C_(tot))of$1619.85 million,and IC has the lowest levelized cost of energy(LCOE)of 0.012$/(kWh).The nuclear Brayton cycle system’s overall performance has been improved due to *** performance of the molten salt reactor combined with the intercooling cycle(MSR-IC)scheme has the greatest improvement,with the net output power(W_(net)),thermal efficiencyη_(t),and exergy efficiency(η_(e))improved by 8.58%,8.58%,and 11.21%,*** performance of the lead-cooled fast reactor combined with the simple recuperation cycle scheme was optimized to increase C_(tot) by 27.78%.In comparison,the internal rate of return(IRR)increased by only 7.8%,which is not friendly to investors with limited *** the nuclear Brayton cycle,the molten salt reactor combined with the recompression cycle scheme should receive priority,and the gas-cooled fast reactor combined with the reheating cycle scheme should be considered carefully.

关键词： Supercritical CO_(2)Brayton cycle Nuclear power generation Thermo-economic analysis Multi-objective optimization Decision-making methods

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Recent process developments in beneficiation and metallurgy of rare earths:A review

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Journal of Rare Earths 2024年第4期42卷 629-642页

作者： Shaokai cheng Wenbo Li Yuexin Han Yongsheng Sun peng Gao Xiaolong zhang School of Resources and Civil Engineering Northeastern UniversityShenyang110819China National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore Resources Shenyang110819China

Rare earth elements(REEs)are irreplaceable materials supporting low-carbon technology and equip-ment,and their commercial demand and strategic position are becoming increasingly *** the continuous depletion of rare earth(RE)resources,developing high-efficiency beneficiation and eco-friendly metallurgical processes has attracted widespread *** paper reviews the major minerals exploited for RE production and their deposits,as well as the beneficiation and metallurgical processes of RE ***,monazite,mixed RE ores,and ion-adsorption clays are the main raw materials in the world to ***-bearing ores(except ion-adsorption minerals)are generally beneficiated by flotation,gravity and magnetic separation *** mainstream metallurgical processes for bastnaesite,monazite and mixed RE concentrates are oxidation roasting-HCl leaching,caustic soda decomposition and high-temperature concentrated sulfuric acid roasting,***-adsorption clays are directly processed by in situ leaching-precipitation/solvent *** achieve the sustainable development of RE resources,it is essential to further explore innovative techniques to achievecomprehensive utilization and cleaner production.

关键词： Rare earths Beneficiation processes Metallurgical processes Cleaner production

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Modeling of LF refining process:a review

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Journal of Iron and Steel Research(International) 2024年第2期31卷 289-317页

作者： Zi-cheng Xin Jiang-shan zhang Kai-xiang peng Jun-guo zhang Chun-hui zhang Qing Liu State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China School of Automation and Electrical Engineering University of Science and Technology BeijingBeijing100083China Tangshan Branch Hebei Iron and Steel Co.Ltd.Tangshan063000HebeiChina Xinjiang Bayi Iron and Steel Co. Ltd.Baosteel GroupWulumuqi830022XinjiangChina

With the increasing demand for energy conservation and emission reduction,more attentions have been paid to the intelligentization,greenization and low carbonization during the transformation and upgrading of steelmaking *** furnace(LF)refining is one of the key procedures in steelmaking process and has been widely used in steelmaking plants for its high equipment matching degree,low equipment investment and outstanding refining *** to the main tasks of LF refining process,the modeling methods of temperature prediction model,slag-making model,alloying model,argon blowing model and model of inclusions behavior were systematically reviewed,and the advantages and disadvantages of each modeling method were *** addition,the technical framework for the future has also been proposed based on existing works,including classification of raw materials,graphic representation of knowledge,introduction,upgradation and management of device/equipment,customization of steelmaking,modeling of refining process,synergy of models,intelligentization of decision-making,automation of control,and digitization of processes and operations,aiming to provide a reference for the modeling and intelligent development of LF refining process.

关键词： LF refining Temperature prediction Slag-making Alloying Argon blowing Inclusion behavior Modeling method

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Microstructure recognition of steels by machine learning based on visual attention mechanism

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Journal of Iron and Steel Research(International) 2024年第4期31卷 909-923页

作者： Xing-yu Chen Lin cheng cheng-yang Hu Yu-peng zhang Kai-ming Wu The State Key Laboratory of Refractories and Metallurgy Hubei Province Key Laboratory of Systems Science on Metallurgical ProcessingInternational Research Institute for Steel TechnologyCollaborative Center on Advanced SteelsWuhan University of Science and TechnologyWuhan 430081HubeiChina Metals Valley and Band(Foshan)Metallic Composite Materials Co. Ltd.Foshan 528000GuangdongChina

U-Net has achieved good performance with the small-scale datasets through skip connections to merge the features of the low-level layers and high-level layers and has been widely utilized in biomedical image segmentation as well as recent microstructure image segregation of the *** representative visual attention mechanism modules,named as squeeze-and-excitation networks,convolutional block attention module,and extended calibration algorithm,were intro-duced into the traditional U-Net architecture to further improve the prediction *** is found that compared with the original U-Net architecture,the evaluation index of the improved U-Net architecture has been significantly improved for the microstructure segmentation of the steels with the ferrite/martensite composite microstructure and pearlite/ferrite composite microstructure and the complex martensite/austenite island/bainite microstructure,which demonstrates the advantages of the utilization of the visual attention mechanism in the microstructure *** reasons for the accuracy improvement were discussed based on the feature maps analysis.

关键词： Microstructure recognition-Steel Machine learning Visual attention mechanism Visualization

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Indefinite Linear Quadratic Optimal Control Problem for Singular Linear Discrete-time System: Krein Space Method

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自动化学报 2007年第6期33卷 635-640页

作者： CUI peng zhang cheng-Hui School of Control Science and Engineering Shandong University Jinan 250061 P. R. China

有限时间地平线不定线性二次(LQ ) 为单个线性分离变化时间的系统的最佳的控制问题被讨论。为单个系统的不定的 LQ 最佳的控制问题能在一个合理假设下面为标准州空间的系统被转变到那。不定的 LQ 最佳的控制问题对为向后的随机的系统的... 详细信息

有限时间地平线不定线性二次(LQ ) 为单个线性分离变化时间的系统的最佳的控制问题被讨论。为单个系统的不定的 LQ 最佳的控制问题能在一个合理假设下面为标准州空间的系统被转变到那。不定的 LQ 最佳的控制问题对为向后的随机的系统的设计的双，这被显示出。因此，最佳的 LQ 控制器能被计算 Kalman 过滤器的获得矩阵获得。为不定的 LQ 问题保证一个唯一的答案的必要、足够的条件被给。这个问题的一个明确的解决方案以 Riccati 差别方程的答案被获得。

关键词：模糊线性二次最佳控制单次线性离散时间系统有限时间差异方程 KaLman过滤

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Interface optimization of graphene paper-Cu composite prepared by electrodeposition

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Journal of Iron and Steel Research(International) 2024年第1期31卷 64-73页

作者： Jing Guo Hai-jing Wang Shuang-juan Liu peng zhang Jing-yu Tang Wei-yang zhang Han-jie Guo peng-cheng Wang Cai Meng School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Institute of High Energy Physics Chinese Academy of SciencesBeijing100049China Advanced Technology and Materials Co. Ltd.Beijing100083China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei230027AnhuiChina

A room-temperature electrodeposition method with an organic electrolyte was developed to fabricate a HNO3-pretreated graphene paper Cu(GP'-Cu)*** improve the interfacial bonding of GP'-Cu composite,magnetron sputtering technology was used to create a"sandwich"structural gradient GP'-Cu *** selection of the intermediate transition layer metal was based on two-dimensional *** electron microscopy,X-ray photoelectron spectroscopy,and other analytical methods confirmed that the addition of an intermediate transition metal(Cr,Ni)layer reduced the gap distance and enhanced the interfacial bonding of the GP'and Cu deposited *** GP'-Ni-Cu composite exhibited the largest increase in tensile strength and *** addition,it had the highest thermal diffusivity and elongation at break among the GP'-Cu,GP'-Cr-Cu and GP'-Ni-Cu composites.

关键词： Graphene paper Two-dimensional disregistry Magnetron sputtering Metal composite

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Rapid Phase Ambiguity Elimination Methods for DOA Estimator via Hybrid Massive MIMO Receive Array

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Chinese Journal of Electronics 2024年第1期33卷 175-184页

作者： Xichao ZHAN Zhongwen SUN Feng SHU Yiwen CHEN Xin cheng Yuanyuan WU Qi zhang Yifan LI peng zhang School of Information and Communication Engineering Hainan University School of Electronic and Optical Engineering Nanjing University of Science and Technology

For a sub-connected hybrid multiple-input multiple-output(MIMO) receiver with K subarrays and N antennas, there exists a challenging problem of how to rapidly remove phase ambiguity in only single time-slot. A direction of arrival(DOA) estimator of maximizing received power(Max-RP) is proposed to find the maximum value of K-subarray output powers, where each subarray is in charge of one sector, and the center angle of the sector corresponding to the maximum output is the estimated true DOA. To make an enhancement on precision, Max-RP plus quadratic interpolation(Max-RP-QI) method is designed. In the proposed Max-RP-QI, a quadratic interpolation scheme is adopted to interpolate the three DOA values corresponding to the largest three receive powers of *** achieve the Cramer Rao lower bound, a Root-MUSIC plus Max-RP-QI scheme is developed. Simulation results show that the proposed three methods eliminate the phase ambiguity during one time-slot and also show low computational complexities. The proposed Root-MUSIC plus Max-RP-QI scheme can reach the Cramer Rao lower bound,and the proposed Max-RP and Max-RP-QI are still some performance losses 2–4 d B compared to the Cramer Rao lower bound.

关键词： Phased arrays Interpolation Wireless sensor networks Direction-of-arrival estimation Simulation Receiving antennas Massive MIMO

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Tracking and Guiding Multiple Laser Beams for Beam and Target Alignment

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International Journal of Automation and computing 2015年第6期12卷 600-610页

作者： peng-cheng zhang De Xu Research Center of Precision Sensing and Control Institute of Automation Chinese Academy of Sciences

An accurate and robust approach for tracking and guiding multiple laser beams is developed, which can be applied to the task of beam and target alignment. Multiple laser spots are firstly detected and recognized from the image sequences of the target and laser spots. Then, the contour tracking algorithm based on the chain code is investigated, in which the shape matching scheme based on the invariant moments is employed to distinguish different spots. When occlusion occurs in the multiple spots tracking procedure,the contour tracking combined with Kalman filter prediction is proposed to obtain the positions of multiple spots in real-time. In order to guide 3 spots to align the target, an incremental proportional integral(PI) controller is employed to make the image features of spots converge to the desired ones. Comparative experiments show that, the proposed tracking method can successfully cope with the fast motion, partial or complete occlusion. The experiment results on spots guiding also exhibit the accurate and robust performance of the strategy. The proposed visual system solves the problem of spots mixing, reduces the alignment time, improves the shooting accuracy and has been successfully applied to the experimental platform.

关键词： Laser spot spot segmentation contour tracking visu

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