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Optimization of the S-band side-coupled cavities for proton acceleration

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Nuclear Science and Techniques 2020年第3期31卷 1-9页

作者： hao-yun Li Xin-Miao Wan wei Chen Chen-Hui shi zhi-Hui Li The Key Laboratory of Radiation Physics and Technology of Ministry of Education Institute of Nuclear Science and Technology Sichuan University

The proton beam with energy around 100 MeV has seen wide applications in modern scientific research and in various ***,proton sources in China fall short for meeting experimental needs owing to the vast size and expensive traditional proton *** Institute of Nuclear Science and Technology of Sichuan University proposed to build a 3 GHz side-coupled cavity linac(SCL)for re-accelerating a 26 MeV proton beam extracted from a CS-30 cyclotron to 120 *** carried out investigations into several vital factors of S-band SCL for proton acceleration,such as optimization of SCL cavity geometry,end cell tuning,and bridge coupler *** demonstrated that the effective shunt impedance per unit length ranged from 22.5 to 59.8 MX/m throughout the acceleration process,and the acceleration gradient changed from 11.5 to 15.7 MV/m when the maximum surface electric field was equivalent to Kilpatrick electric *** obtained equivalent circuit parameters of the biperiodic structures and applied them to the end cell tuning;results of the theoretical analysis agreed well with the 3D *** designed and optimized a bridge coupler based on the previously obtained biperiodic structure parameters,and the field distribution un-uniformness was\1.5%for a two-tank *** radio frequency power distribution system of the linac was obtained based on the preliminary beam dynamics design.

关键词： Proton beam Side-coupled cavity linac Accelerating cavity Biperiodic structure Bridge coupler

Effect of 6H-SiC crystal growth shapes on thermo-elastic stress in the growing crystal

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International Journal of Minerals,Metallurgy and Materials 2012年第7期19卷 622-627页

作者： Yong-gui shi Pei-yun Dai Jian-feng yang zhi-hao Jin Hu-lin Liu State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi'an 710049 China

The effect of 6H-SiC crystal growth shapes on the thermo-elastic stress distribution in the growing crystal was systematically in- vestigated by using a finite element method. The thermo-elastic stress distribution in the crystal with a flat growth shape was more homoge- neous than that in the crystals with concave and convex growth shapes, and the value of thermo-elasticity in the crystal with a fiat growth shape was also smaller than that in the two other types of crystals. The maximum values of thermo-elastic stress appeared at interfaces be- tween the crystal and the graphite lid. If the lid was of the same properties as 6H-SiC, the thermo-elastic stress would decrease in two orders of magnitude. Thus, to grow 6H-SiC single crystals of high quality, a transition layer of SiC formed by deposition or reaction is suggested; meanwhile the thermal field in the growth chamber should be adjusted to maintain the crystals with fiat growth shapes.

关键词： silicon carbide thermo-elasticity physical vapor transport single crystals crystal growth finite element method

Analog rise-time discriminator for CdZnTe detector

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Nuclear Science and Techniques 2017年第4期28卷 59-65页

作者： Chuan-hao Hu Guo-Qiang Zeng Liang-Quan Ge shi-Long wei Jian yang Qiang Li Hong-zhi Li Chengdu University of Technology Chengdu 610059 China National Ocean Technology Center Tianjin 300112 China

Due to variable time for charge collection,energy resolution of nuclear detectors declines,especially compound semiconductor detectors like cadmium zinc telluride(CdZnTe) *** solve this problem,an analog rise-time discriminator based on charge comparison principle is *** reference charge signal after attenuation is compared with the deconvoluted and delayed current *** is found that the amplitude of delayed current signal is higher than that of the reference charge signal when rise time of the input signal is shorter than the discrimination time,thus generating gating signal and triggering DMCA(digital multi-channel analyzer) to receive the total integral charge *** rise time of the input signal is longer than discrimination time,DMCA remains inactivated and the corresponding total integral charge signal is *** results show that combination of the designed rise-time discriminator and DMCA can reduce hole tailing of CdZnTe detector *** resolution of the system is 0.98%@662 keV,and it is still excellent under high counting rates.

关键词： Analog rise-time discriminator CdZnTe detector Charge comparison principle

A Novel Bat Algorithm based on Cross Boundary Learning and Uniform Explosion Strategy

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Applied Mathematics(A Journal of Chinese Universities) 2019年第4期34卷 480-502页

作者： YONG Jia-shi HE Fa-zhi LI hao-ran ZHOU wei-qing School of Computer Science Wuhan UniversityWuhan 430072China State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

Population-based algorithms have been used in many real-world *** algorithm(BA)is one of the states of the art of these *** of the super bat,on the one hand,BA can converge quickly;on the other hand,it is easy to fall into local ***,for typical BA algorithms,the ability of exploration and exploitation is not strong enough and it is hard to find a precise *** this paper,we propose a novel bat algorithm based on cross boundary learning(CBL)and uniform explosion strategy(UES),namely BABLUE in short,to avoid the above contradiction and achieve both fast convergence and high *** from previous opposition-based learning,the proposed CBL can expand the search area of population and then maintain the ability of global exploration in the process of fast *** order to enhance the ability of local exploitation of the proposed algorithm,we propose UES,which can achieve almost the same search precise as that of firework explosion algorithm but consume less computation *** is tested with numerous experiments on unimodal,multimodal,one-dimensional,high-dimensional and discrete problems,and then compared with other typical intelligent optimization *** results show that the proposed algorithm outperforms other algorithms.

关键词： Optimization Bat algorithm Cross boundary learning Uniform explosion strategy

Ecological study of cave nectar bats reveals low risk of direct transmission of bat viruses to humans

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Zoological Research 2022年第4期43卷 514-522页

作者： Kai Zhao wei Zhang Bei Li shi-Zhe Xie Fan Yi Ren-Di Jiang yun Luo Xiang-yang He yun-zhi Zhang Zheng-Li shi Li-Biao Zhang Xing-Lou yang CAS Key Laboratory of Special Pathogens and Biosafety Wuhan Institute of VirologyChinese Academy of SciencesWuhanHubei 430071China University of Chinese Academy of Sciences Beijing 100049China Guangdong Key Laboratory of Animal Conservation and Resource Utilization Guangdong Public Laboratory of Wild Animal Conservation and UtilizationInstitute of ZoologyGuangdong Academy of SciencesGuangzhouGuangdong 510260China School of Public Health Dali UniversityDaliYunnan 671003China

Bats are reservoirs of various *** widely distributed cave nectar bat(Eonycteris spelaea)is known to carry both filoviruses and ***,the potential transmission of theses bat viruses to humans is not fully *** this study,we tracked 16 *** bats in Mengla County,yunnan Province,China,using miniaturized GPS devices to investigate their movements and potential contact with ***,to determine the prevalence of coronavirus and filovirus infections,we screened for the nucleic acids of the Měnglàvirus(MLAV)and two coronaviruses(GCCDC1-CoV and HKU9-CoV)in anal swab samples taken from bats and for antibodies against these viruses in human serum *** of the serum samples were found to contain antibodies against the bat *** GPS tracking results showed that the bats did not fly during the daytime and rarely flew to residential *** foraging range of individual bats also varied,with a mean cumulative nightly flight distance of 25.50 km and flight speed of up to 57.4 km/*** together,these results suggest that the risk of direct transmission of GCCDC1-CoV,HKU9-CoV,and MLAV from *** bats to humans is very low under natural conditions.

关键词： Bats Eonycteris spelaea GPS tracking GCCDC1-CoV HKU9-CoV Měnglàvirus

Effect of axial vertical vibration on degeneration of lumbar intervertebral discs in modified bipedal rats: An in-vivo study

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Asian Pacific Journal of Tropical Medicine 2017年第7期10卷 781-784页

作者： Xiao Liang hao Shen wei-Dong shi Shan Ren wei Jiang hao Liu Peng yang zhi-Yong Sun Jun Lin Hui-Lin yang Department of Orthopaedic Surgery The First Affiliated Hospital of Soochow University Intensive Care Unit Department The First Affiliated Hospital of Medical CollegeShihezi University Department of Nephrology The Affiliated Hospital of Qingdao University

Objective: To assess the effects of axial vibrations on gene expression and lumbar intervertebral disc degeneration in vivo. Methods: A modified bipedal rat model was established using a brachial plexus rhizotomy approach to imitate human upright posture. The experimental animals were randomly divided into three groups: control, vertical vibration, and whole-body vibration. Gene expression in degeneration of the intervertebral discs was assessed by reverse transcription-quantitative polymerase chain reaction. Results: The expression of aggrecan, Col1α1, Col2α1, and decorin were shown to be up-regulated in 14-week-old rats in the vertical vibration and whole-body vibration groups, whereas biglycan and versican expression was down-regulated in 14-week-old rats of the two experimental groups. Furthermore, biglycan and versican expression levels were shown to be lower in the whole-body vibration group than in the vertical vibration group(P<0.05). Conclusions: This in-vivo study demonstrated that vibrations can influence the expression of anabolic genes. Furthermore, whole-body vibrations seem to have a greater effect in this regard than vertical vibrations. A new method is expected to relieve the low back pain of the patients through our research.

关键词： Intervertebral disc Vibration Animal model Gene expression

An Organic Small Molecule as a Solid Additive in Non-Fullerene Organic Solar Cells with Improved Efficiency and Operational Stability

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Chinese Journal of Polymer Science 2023年第2期41卷 194-201页

作者： Yi-Nuo yang Xiao-Ming Li shi-Jie Wang Xiao-Peng Duan yun-hao Cai Xiao-Bo Sun Dong-Hui wei wei Ma Yan-Ming Sun School of Chemistry Beihang UniversityBeijing100191China State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an710049China The College of Chemistry and Molecular Engineering Zhengzhou UniversityZhengzhou450001China

The use of additive is an effective approach to optimize the active layer morphology and improve the power conversion efficiency(PCE)of organic solar cells(OSCs).However,residual solvent additives always lead to undesirably compromise the stability of *** this work,an organic small molecule BBT-Cl was designed and used as a novel solid additive to partly replace solvent additive to fabricate highperformance *** synergistic effect of the dual additives on the optical property,morphology and photovoltaic characteristics of the PM6:Y6 based non-fullerene OSCs have been systematically *** introduction of BBT-Cl could effectively enhance the crystallinity of the blend and promote charge extraction and ***,the OSCs processed by the dual additives exhibit a high PCE of 17.73%,which is obviously higher than OSCs with CN additive(16.48%).Meanwhile,BBT-Cl based dual additives treatment has also been successfully introduced into another two non-fullerene OSCs to verify its general ***,20%PCE aging is significantly prolonged from 720 min to 2880 min for the devices proceeded with the dual *** work highlights the great potential of solid additive in the fabrication of efficient OSCs with excellent stability.

关键词： Organic solid additive Morphology Dual additives Organic solar cells Operational stability

Generation and Measurement of Isolated 160-Attosecond XUV Laser Pulses at 82eV

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Chinese Physics Letters 2013年第9期30卷 54-57页

作者： ZHAN Min-Jie YE Peng TENG hao HE Xin-Kui ZHANG wei ZHONG shi-yang WANG Li-Feng yun Chen-Xia wei zhi-Yi Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190

Isolated attosecond extreme-ultraviolate(XUV)pulses are generated based on high-harmonic-generation from a neon gas cell driven by carrier-envelope phase stabilized sub-5-fs Ti:sapphire laser pulses at repetition rate of *** characterization of isolated attosecond XUV pulses is demonstrated to be 160-attosecond by attosecond streaking *** development of attosecond source and streaking spectroscopy will allow scientists to explore the electron dynamics in matter.

关键词： spectroscopy second extreme

Revisit of GeV Gamma-Ray Emission from Orion B with the Fermi Large Area Telescope

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Research in Astronomy and Astrophysics 2024年第9期24卷 128-135页

作者： wei Zeng Xiao-Na Sun Rui-zhi yang Jia-Chun He Zhao-Dong shi Ting-Ting Ge yun-Feng Liang En-wei Liang Guangxi Key Laboratory for Relativistic Astrophysics School of Physics Science and TechnologyGuangxi UniversityNanning 530004China Department of Astronomy School of Physical SciencesUniversity of Science and Technology of ChinaHefei 230026China CAS Key Labrotory for Research in Galaxies and Cosmology University of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China

We revisit the γ-ray emission above 300 Me V towards the massive star-forming region of Orion B by adopting14 yr observations with the Fermi Large Area Telescope and utilizing the updated software *** extended γ-ray emission region around Orion B is resolved into two components(region Ⅰ and region Ⅱ).The γ-ray spectrum of region I agrees with the predicted γ-ray spectrum assuming the cosmic ray(CR)density is the same as that of Alpha Magnetic Spectrometer(AMS-02)measured ***γ-ray emissivity of region II appears to be deficit at low energy band(E<3 GeV).Through modeling we find that CR densities exhibit a significant deficit below 20 Ge V,which may be caused by a slow diffusion inside the dense *** is probably caused by an increased magnetic field whose strength increases with the gas density.

关键词： (ISM:)cosmic rays gamma-rays:ISM (Galaxy:)open clusters and associations:individual(NGC 2023 NGC 2024 NGC 2068 and NGC 2071)