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Design,fabrication,and cold test of an S-band high-gradient accelerating structure for compact proton therapy facility

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Nuclear Science and Techniques 2021年第4期32卷 38-48页

作者： Yu Zhang wen-cheng Fang Xiao-Xia Huang Jian-Hao Tan cheng Wang chao-Peng Wang Zhen-Tang Zhao Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China ShanghaiTech University Shanghai 201210China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201204China

An S-band high-gradient accelerating structure is designed for a proton therapy linear accelerator(linac)to accommodate the new development of compact,singleroom facilities and ultra-high dose rate(FLASH)*** optimize the design,an efficient optimization scheme is applied to improve the simulation *** S-band accelerating structure with 2856 MHz is designed with a low beta of 0.38,which is a difficult structure to achieve for a linac accelerating proton particles from 70 to 250 MeV,as a high gradient up to 50 MV/m is required.A special design involving a dual-feed coupler eliminates the dipole field *** paper presents all the details pertaining to the design,fabrication,and cold test results of the S-band high-gradient accelerating structure.

关键词： S-band High gradient Accelerating structure Compact Single-room facility Dual-feed coupler Cold test

Effects of embedding direct reduction followed by magnetic separation on recovering titanium and iron of beach titanomagnetite concentrate

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Journal of Iron and Steel Research International 2017年第2期24卷 156-164页

作者： chao Geng Ti-chang Sun You-wen Ma cheng-yan Xu Hui-fen Yang School of Civil and Environmental Engineering University of Science and Technology Beijing Beijing 100083 China

Embedding direct reduction followed by magnetic separation was conducted to fully recover iron and titanium separately from beach titanomagnetite （TTM）. The influences of reduction conditions, such as molar ratio of C to Fe, reduction time, and reduction temperature, were studied. The results showed that the TTM concentrate was reduced to iron and iron-titanium oxides, depending on the reduction time, and the reduction sequence at 1 200℃ was suggested as follows ： Fe2.75 Ti0.25O4→Fe2TiO4→FeTiO3→FeTi2O5. The reduction temperature played a considerable role in the reduction of TTM concentrates. Increasing temperature from 1 100 to 1 200℃ was beneficial to recovering titanium and iron, whereas the results deteriorated as temperature increased further. The results of X-ray diffraction and scanning electron microscopy analyses showed that low temperature （≤1100℃） was unfavorable for the gasification of reductant, resulting in insufficient reducing atmosphere in the reduction process. The molten phase was formed at high temperatures of 1250-1 300℃, which accelerated the migration rate of metallic particles and suppressed the diffusion of reduction gas, resulting in poor reduction. The optimum conditions for reducing TTM concentrate are as follows： molar ratio of C to Fe of 1.68, reduction time of 150 min, and reduction temperature of 1 200℃. Under these conditions, direct reduction iron powder, assaying 90.28 mass% TFe and 1.73 mass% TiO2 with iron recovery of 90.85%, and titanium concentrate, assaying 46.24 mass% TiO2 with TiO2 recovery of 91.15%, were obtained.

关键词： Titanomagnetite concentrate Direct reduction Reduction condition Direct reduction iron powder Magnetic separation

Wideband high gain millimeter wave antenna based on wavy power divider for millimeter wave radar sensor

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The Journal of China Universities of Posts and Telecommunications 2025年

作者： Zhang Shuanggen Yu Tao Wang Yulan Zhou Ran cheng Zhihua School of Integrated Circuit Science and Engineering， Tianjin University of Technology

In this paper， a broadband high gain millimeter wave radar array antenna based on a wavy power divider is proposed. The radar antenna comprises a wavy power divider and a 10-element array antenna. By adjusting the wavy radius of the power divider， the surface current of the power divider is altered， resulting in better impedance matching with the antenna. This ultimately leads to a significant improvement in bandwidth performance. The 410 millimeter wave radar antenna loaded with wavy power divider exhibits an approximate enhancement of 3 GHz compared to traditional microstrip power divider antennas， and an average gain increase of 2.42 dB within the vehicle millimeter wave radar frequency band relative to the improved gradient power divider structure. The 410 millimeter wave radar antenna loaded with wavy power divider possesses the characteristics of high gain and broad bandwidth.

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Intracavity Optical Deposition of Graphene Saturable Absorber for Low-Threshold Passive Mode-Locking of a Fiber Laser

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Chinese Physics Letters 2013年第2期30卷 121-123页

作者： LUO Zhi-chao CAO wen-Jun LUO Ai-Ping XU wen-cheng Laboratory of Nanophotonic Functional Materials and Devices School of Information and Optoelectronic Science and EngineeringSouth China Normal UniversityGuangzhou 510006

A compact,intracavity optical deposition of graphene saturable absorber(SA)for low-threshold passively mode-locked fiber laser is proposed and *** optical deposition is implemented in the laser cavity by using a slot *** the fabricated graphene SA,the fiber laser achieves self-starting,passively mode-locked operation at a low threshold of 32 mW pump power,delivering a 13.1-MHz 2.36-ps pulse train.

关键词： passive fiber laser

Printing perovskite and graphene parallel structure-based optical-mechanical sensors for human-machine interaction

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Science China Technological Sciences 2025年

作者： Sisi CHEN Jiemin ZHANG Nan cheng wenbo LI Jing LIU Hongfei XIE Jie ZHANG Yueying cheng Xiaotong ZHAO Meng SU Yanlin SONG Key Laboratory of Green Printing CAS Research/Education Center for Excellence in Molecular Sciences Institute of ChemistryChinese Academy of Sciences (ICCAS) University of Chinese Academy of Sciences Weiyang College Tsinghua University Department of Cardiovascular Surgery First Medical Center PLA General Hospital AECC Beijing Institute of Aeronautical Materials Beijing Institute of Graphene Technology Beijing Engineering Research Centre of Graphene Application School of Integrated Circuit & Beijing National Research Center for Information Science and Technology (BNRist) Tsinghua University

Surgical robots are designed to provide enhanced precision and dexterity compared to manual surgical procedures,which mainly rely on multimodal sensing technologies for the surgeon to seamlessly operate the robotic arms and *** with single-mode sensors, optical and mechanical bi-modal sensors provide improved precision, enhanced safety,and robustness of human-machine interaction systems. Here, the template-guided and pneumatic printing technologies are combined to construct perovskite and graphene parallel structures with both optical and mechanical sensing capabilities. The printed uniformly crystallized perovskite microstructure exhibits fast and sensitive photoelectric response characteristics,enabling shadow recognition functionality. The combination of graphene and elastic rubber endows the great printability to prepare parallel structures near the perovskite arrays for force sensing capabilities. Thus, the printed perovskite and graphene structures possess non-contact optical sensing capabilities to detect hand position by recognizing shadows between the hand and the sensor, as well as contact mechanical sensing capabilities to detect touch force applied by the hand. It provides a synergistic platform for real-time and multidimensional feedback to improve human-machine interaction.

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Phase saddle point transformation-enabled mode-adaptive detection of acoustic orbital angular momentum with high efficiency and low crosstalk

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Science China(Physics,Mechanics & Astronomy) 2025年

作者： Kai Wu Yang Tan Jingjing Liu Bin Liang Jianchun cheng Collaborative Innovation Center of Advanced Microstructures and Key Laboratory of Modern Acoustics MOE Institute of AcousticsDepartment of Physics Nanjing University

Acoustic orbital angular momentum (OAM) provides an infinite set of orthogonal bases in Hilbert space and significantly boosts the link capacity and data transmission rate. High-capacity and low-crosstalk OAM detection within compact physical space is highly desired to effectively harness this spatial dimension of sound wave, but the existing mechanisms generally either operate only for finite OAMs with predetermined mode orders or rely on complicated active devices. Here, we propose a phase saddle point (PSP) transformation mechanism for distinguishing and demultiplexing acoustic OAM modes in a passive, mode-adaptive,high-efficiency, and high-accuracy paradigm. The phase mask characterized by a PSP in the specific area is created through the single-pass log-polar transformation without prior information of incident modes, whose interaction with incident vortex beams of different OAM modes will yield the translation of the stationary phase point and thereby generate the corresponding focused line spots at distinct lateral positions. We theoretically elucidate the mode-adaptive response of PSP transformation by deriving the quantitative relationship between the OAM order and line spot offset. This mode adaptability enables our mechanism to detect OAM of arbitrary mode orders and mode numbers with the inter-mode crosstalk being effectively suppressed, beyond attainable with the existing methods. The effectiveness of our proposed mechanism is validated by demonstrating several distinct examples of single-mode OAM sorting and multi-mode synthesized vortex beam demultiplexing. We anticipate this modeadaptive methodology, designed for compact dimensions and featuring with low crosstalk and uniform efficiency, will find important applications in OAM information processing.

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Identification methods for anomalous stress region in coal roadways based on microseismic information and numerical simulation

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International Journal of Mining Science and Technology 2017年第3期27卷 525-530页

作者： Liu chao Li Shugang cheng cheng cheng Xiaoyu College of Safety Science and Engineering Xi'an University of Science & Technology Xi'an 710054 China Key Laboratory of Western Mine Exploitation and Hazard Prevention Ministry of Education Xi'an University of Science & Technology Xi'an 710054 China

It is believed that the microseismicity induced by mining effect and gas gradient disturbance stress is a precursor to the essential characteristics of roadway unstability. In order to effectively identify and evaluate the stability of coal roadways in the process of mine development and extraction, a microseismic monitoring system was deployed for the study of the stress evolution process, damage degree and distribution characteristics in the tailgate and headgate. The mine under study is the 62113 outburst working face of Xin Zhuangzi coalmine in Huainan mining area. The whole process of microfractures initiation,extension, interaction and coalescence mechanisms during the progressive failure processes of the coal rock within the delineated and typical event clusters were investigated by means of a two dimensional realistic failure process analysis code(RFPA2D-Flow). The results show that the microseismic events gradually create different-sized event clusters. The microseismicity of the tailgate is significantly higher than that of the headgate. The study indicates that the greater anomalous stress region matches the area where microfractures continuously develop and finally connect to each other and form a fissure *** to the mine layout and stress concentration, the ruptured area is mainly located on the left shoulder of the tailgate roof. The potential anomalous stress region of the coal roadway obtained by numerical simulation is relatively in good agreement with the trend of spatial macro evolution of coal rock microfractures captured by the microseismic monitoring system. The research results can provide important basis for understanding instability failure mechanism of deep roadway and microseismic activity law in complex geologic conditions, and it ultimately can be used to guide the selection and optimization of reinforcement and protection scheme.

关键词： Microseismic monitoring technology Numerical simulation Anomalous stress region Event clusters Microcracks

Mutual regulation of microglia and astrocytes after Gas6 inhibits spinal cord injury

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Neural Regeneration Research 2025年第2期20卷 557-573页

作者： Jiewen Chen Xiaolin Zeng Le Wang wenwu Zhang Gang Li Xing cheng Peiqiang Su Yong Wan Xiang Li Department of Spine Surgery The First Affiliated HospitalSun Yat-sen UniversityGuangzhouGuangdong ProvinceChina Guangdong Province Key Laboratory of Orthopedics and Traumatology GuangzhouGuangdong ProvinceChina

Invasive inflammation and excessive scar formation are the main reasons for the difficulty in repairing nervous tissue after spinal cord *** and astrocytes play key roles in the spinal cord injury micro-environment and share a close ***,the mechanisms involved remain *** this study,we found that after spinal cord injury,resting microglia(M0)were polarized into pro-inflammatory phenotypes(MG1 and MG3),while resting astrocytes were polarized into reactive and scar-forming *** expression of growth arrest-specific 6(Gas6)and its receptor Axl were significantly down-regulated in microglia and astrocytes after spinal cord *** vitro experiments showed that Gas6 had negative effects on the polarization of reactive astrocytes and pro-inflammatory microglia,and even inhibited the cross-regulation between *** further demonstrated that Gas6 can inhibit the polarization of reactive astrocytes by suppressing the activation of the Yes-associated protein signaling ***,in turn,inhibited the polarization of pro-inflammatory microglia by suppressing the activation of the nuclear factor-κB/p65 and Janus kinase/signal transducer and activator of transcription signaling *** vivo experiments showed that Gas6 inhibited the polarization of pro-inflammatory microglia and reactive astrocytes in the injured spinal cord,thereby promoting tissue repair and motor function ***,Gas6 may play a role in the treatment of spinal cord *** can inhibit the inflammatory pathway of microglia and polarization of astrocytes,attenuate the interaction between microglia and astrocytes in the inflammatory microenvironment,and thereby alleviate local inflammation and reduce scar formation in the spinal cord.

关键词： astrocytes Axl cell polarization Gas6 Hippo signal inflammatory micro-environment intercellular interaction microglia single-cell sequencing spinal cord injury

Odd elasticity realized by piezoelectric material with linear feedback

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Science China(Physics,Mechanics & Astronomy) 2021年第11期64卷 108-117页

作者： wen cheng Gengkai Hu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China

The systems exhibiting sustainable external energy exchange are abundant,e.g.,biological organisms’reaction to external stimuli while maintaining a constant energy exchange with the *** a linear mechanical system exhibiting an external energy gain or release,the recently proposed odd elasticity theory can characterize the overall stress and strain ***,realizing the required odd elasticity is still *** this work,we discovered that the smart materials with designed feedbacks can achieve this odd elasticity,thereby providing a practical platform to analyze the phenomenon related to this novel elasticity *** also demonstrated this idea by designing a non-reciprocal Rayleigh wave via odd elasticity and the equivalent piezoelectricity with linear *** underpinned electric energy scenario was also *** work establishes a method to easily realize the materials with odd elastic behaviors and explore the rich phenomena related to nonHermitian systems.

关键词： odd elasticity piezoelectricity feedback Rayleigh wave unidirectional invisibility