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Searching for^(76)Ge neutrinoless double beta decay with the CDEX-1B experiment

Chinese Physics C 2024年第10期48卷 11-22页

作者： Bing-Tao Zhang Jun-Zheng Wang li-Tao Yang Qian Yue Ke-Jun Kang Yuan-Jing li Hai-Peng An C.Greeshma Jian-Ping Chang Yun-Huan Chen Jian-Ping Cheng Wen-Han Dai Zhi Deng Chang-Hao Fang Xin-Ping Geng Hui Gong Qiu-Ju Guo Xu-Yuan Guo li He Sheng-ming He Jin-Wei Hu Han-Xiong Huang Tu-Chen Huang Hai-Tao Jia Xi Jiang S.Karmakar Hao-Bin li Jian-Min li Jin li Qian-Yun li ren-ming-jie li Xue-Qian li Yu-Lan li Yi-Fan liang Bin liao Fong-Kay lin Shin-Ted lin Jia-Xuan liu Shu-Kui liu Yan-Dong liu Yu liu Yuan-Yuan liu Zhong-Zhi liu Hao Ma Yu-Cai Mao Qi-Yuan Nie Jin-Hua Ning Hui Pan Ning-Chun Qi jie ren Xi-Chao Ruan Ze She Manoj Kumar Singh Tian-Xi Sun Chang-Jian Tang Wei-You Tang Yang Tian Guang-Fu Wang li Wang Qing Wang Yu-Feng Wang Yun-Xiang Wang Henry-Tsz-King Wong Shi-Yong Wu Yu-Cheng Wu Hao-Yang Xing Rui Xu Yin Xu Tao Xue Yu-Lu Yan Nan Yi Chun-Xu Yu Hai-Jun Yu Jian-Feng Yue ming Zeng Zhi Zeng Feng-Shou Zhang Lei Zhang Zhen-Hua Zhang Zhen-Yu Zhang Kang-Kang Zhao ming-Gang Zhao Ji-Fang Zhou Zu-Ying Zhou Jing-Jun Zhou Key Laboratory of Particle and Radiation Imaging(Ministry of Education)and Department of Engineering Physics Tsinghua UniversityBeijing 100084 Department of Physics Tsinghua UniversityBeijing 100084 Institute of Physics Academia SinicaTaipei 11529 NUCTECH Company Beijing 100084 YaLong River Hydropower Development Company Chengdu 610051 College of Nuclear Science and Technology Beijing Normal UniversityBeijing 100875 College of Physics Sichuan UniversityChengdu 610065 School of Physics Peking UniversityBeijing 100871 Department of Nuclear Physics China Institute of Atomic EnergyBeijing 102413 Sino-French Institute of Nuclear and Technology Sun Yat-sen UniversityZhuhai 519082 School of Physics Nankai UniversityTianjin 300071 Department of Physics Banaras Hindu UniversityVaranasi 221005 Department of Physics Beijing Normal UniversityBeijing 100875

We operated a p-type point contact high purity germanium(PPCGe)detector(CDEX-1B,1.008 kg)in the China Jinping Underground Laboratory(CJPL)for 500.3 days to search for neutrinoless double beta(0νββ)decay of^(76)Ge.A total of 504.3 kg⋅day effective exposure data was *** anti-coincidence and the multi/single-site event(MSE/SSE)discrimination methods were used to suppress the background in the energy region of interest(ROI,1989–2089 keV for this work)with a factor of 23.A background level of 0.33 counts/(keV⋅kg⋅yr)was *** lower limit on the half life of^(76)Ge 0νββdecay was constrained as T_(1/2)^(0ν)>1.0×10^(23)yr(90%C.L.),corresponding to the upper limits on the effective Majorana neutrino mass:<3.2–7.5 eV.

关键词： neutrinoless double beta decay CDEX point-contact germanium detector ^(76)Ge

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Intelligent extraction of road cracks based on vehicle laser point cloud and panoramic sequence images

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Journal of Road Engineering 2024年第1期4卷 69-79页

作者： ming Guo li Zhu ming Huang jie Ji Xian ren Yaxuan Wei Chutian Gao School of Geomatics and Urban Spatial Informatics Beijing University of Civil Engineering and ArchitectureBeijing 102616China Engineering Research Centre of Representative Building and Architectural Heritage Database Ministry of EducationBeijing 100044China Key Laboratory of Modern Urban Surveying and Mapping National Administration of SurveyingBeijing 102616China School of Civil and Transportation Engineering Beijing University of Civil Engineering and ArchitectureBeijing 102616China

In light of the limited efficacy of conventional methods for identifying pavement cracks and the absence of comprehensive depth and location data in two-dimensional photographs,this study presents an intelligent strategy for extracting road *** methodology involves the integration of laser point cloud data obtained from a vehicle-mounted system and a panoramic sequence of *** study employs a vehicle-mounted liDAR measurement system to acquire laser point cloud and panoramic sequence image data simultaneously.A convolutional neural network is utilized to extract cracks from the panoramic sequence *** extracted sequence image is then aligned with the laser point cloud,enabling the assignment of RGB information to the vehicle-mounted three dimensional(3D)point cloud and location information to the two dimensional(2D)panoramic ***,a threshold value is set based on the crack elevation change to extract the aligned roadway point *** three-dimensional data pertaining to the cracks can be *** experimental findings demonstrate that the use of convolutional neural networks has yielded noteworthy outcomes in the extraction of road *** utilization of point cloud and image alignment techniques enables the extraction of precise location data pertaining to road *** approach exhibits superior accuracy when compared to conventional ***,it facilitates rapid and accurate identification and localization of road cracks,thereby playing a crucial role in ensuring road maintenance and traffic ***,this technique finds extensive application in the domains of intelligent transportation and urbanization *** technology exhibits significant promise for use in the domains of intelligent transportation and city development.

关键词： Road crack extraction Vehicle laser point cloud Panoramic sequence images Convolutional neural network

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Diophantine equations and Fermat's last theorem for multivariate(skew-)polynomials

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 159-173页

作者： PAN jie JIA Yu-ming li Fang School of Mathematical Sciences Zhejiang UniversityHangzhou 310058China Henan Experimental High School Zhengzhou 450003China

Fermat’s Last Theorem is a famous theorem in number theory which is diﬃcult to ***,it is known that the version of polynomials with one variable of Fermat’s Last Theorem over C can be proved very *** aim of this paper is to study the similar problems about Fermat’s Last Theorem for multivariate(skew)-polynomials with any characteristic.

关键词： Fermat's last theorem polynomial ring skew polynomial ring

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Simplified quantitative analysis method and its application in the insitu synthesized copper-based azide chips

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Defence Technology（防务技术） 2024年第2期32卷 309-316页

作者： jie ren Yunfeng li mingyu li Xingyu Wu Jiabao Wang Qingxuan Zeng State Key Laboratory of Explosion and Technology Beijing Institute of TechnologyBeijing 100081China

Copper-based azide(Cu(N_(3))2 or CuN_(3),CA)chips synthesized by in-situ azide reaction and utilized in miniaturized explosive systems has become a hot research topic in recent ***,the advantages of in-situ synthesis method,including small size and low dosage,bring about difficulties in quantitative analysis and differences in ignition capabilities of CA *** aim of present work is to develop a simplified quantitative analysis method for accurate and safe analysis of components in CA chips to evaluate and investigate the corresponding ignition *** this work,Cu(N_(3))2 and CuN_(3)components in CA chips were separated through dissolution and distillation by utilizing the difference in solubility and corresponding content was obtained by measuring N_(3)-concentration through *** spectrophotometry method was optimized by studying influencing factors and the recovery rate of different separation methods was studied,ensuring the accuracy and reproducibility of test *** optimized method is linear in range from 1.0-25.0 mg/L,with a correlation coefficient R^(2)=0.9998,which meets the requirements of CA chips with a milligram-level content *** with the existing ICP method,component analysis results of CA chips obtained by spectrophotometry are closer to real component content in samples and have satisfactory ***,as its application in miniaturized explosive systems,the ignition ability of CA chips with different component contents for direct ink writing CL-20 and the corresponding mechanism was *** study provided a basis and idea for the design and performance evaluation of CA chips in miniaturized explosive systems.

关键词： Copper-based azide chips Spectrophotometry Separation method Quantitative analysis Ignition ability

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Identification of anomalous fast bulk events in a p-type point-contact germanium detector

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Nuclear Science and Techniques 2022年第5期33卷 53-67页

作者： ren-ming-jie li Shu-Kui liu Shin-Ted lin li-Tao Yang Qian Yue Chang-Hao Fang Hai-Tao Jia Xi Jiang Qian-Yun li Yu liu Yu-Lu Yan Kang-Kang Zhao Lei Zhang Chang-Jian Tang Hao-Yang Xing Jing-Jun Zhu College of Physics Sichuan UniversityChengdu 610065China Key Laboratory of Particle and Radiation Imaging(Ministry of Education)and Department of Engineering Physics Tsinghua UniversityBeijing 100084China

The ultralow detection threshold,ultralow intrinsic background,and excellent energy resolution of ptype point-contact germanium detectors are important for rare-event searches,in particular for the detection of direct dark matter interactions,coherent elastic neutrino-nucleus scattering,and neutrinoless double beta *** bulk events with an extremely fast rise time are observed in the CDEX-1B *** report a method of extracting fast bulk events from bulk events using a pulse shape simulation and reconstructed source experiment *** data and the distribution of X-rays generated by intrinsic radioactivity verified that the fast bulk experienced a single hit near the passivation *** performance of this germanium detector indicates that it is capable of single-hit bulk spatial resolution and thus provides a background removal technique.

关键词： p-type point-contact germanium detector Dark matter Pulse shape analysis Anomalous fast bulk events

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Topology optimization of modular structures with multiple assemblies and applications to airborne shelves

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Chinese Journal of Aeronautics 2024年第4期37卷 321-332页

作者： jie WANG Tong GAO ming li Jihong ZHU Longlong SONG Weihong ZHANG State IJR Center of Aerospace Design and Additive Manufacturing Northwestern Polytechnical UniversityXi’an 710072China Beijing Specialized Machinery Institute Beijing 100143China

This work is devoted to the aeronautical application of topology optimization for modular structures with multiple assemblies that consist of repeated standard modules and optional *** kinds of structures are widely used owing to their transportability,reconfigurability,low manufacturing and service *** this work,the design of airborne shelves with modular structures characterized by the standard module configuration is formulated for the first time as a topology optimization problem of multiple assemblies and multiple load cases subjected to the volume *** is shown that the weighted compliance design of multiple assemblies is a compromising solution compared to the optimization result of each individual assembly of standard ***,the performance of optimized airborne shelves with the modular structures can effectively be ameliorated with the help of reinforcements.

关键词： Topology optimization Modular structures Multiple assemblies Standard modules Airborne shelves

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Acaricidal effect of the antimicrobial metabolite xenocoumacin 1 on spider mite control

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Journal of Integrative Agriculture 2024年第3期23卷 948-959页

作者： Jiaxing Wei Hong Yan jie ren Guangyue li Bo Zhang Xuenong Xu Institute of Plant Protection Chinese Academy of Agricultural SciencesBeijing 100193China State Key Laboratory for Biology of Plant Diseases and Insect Pests Beijing 100193China Key Laboratory of Natural Enemies Insects Ministry of Agriculture and Rural AffairsBeijing 100193China

The two-spotted spider mite,Tetranychus urticae Koch,is one of the most harmful pests in many agroecosystems *** effectively manage this pest,there is an urgent need to develop novel bio-active acaricides that support integrated pest management strategies targeting *** this study,we explored the acaricidal effects of xenocoumacin 1 (Xcn1) on *** and its predator Neoseiulus californicus using the highly puri?ed ***1 was extracted and purified from the cell-free supernatant of the Xenorhabdus nematophila CB6 mutant constructed by the easy promoter activated compound identi?cation (easyPACId) *** the concentration of Xcn1 exceeded 100μg mL~(–1),the survival rate of spider mite adults declined to below 40%and the fecundity was decreased by 80%at six days *** concentrations of 25 and 50μg mL~(–1),Xcn1 signi?cantly impeded spider mite development by inhibiting the ***,neither concentration had any adverse effects on the survival or reproduction of the predatory mite *** results from laboratory and semi-?eld experiments consistently demonstrated the effectiveness of the antimicrobial metabolite Xcn1 in controlling pest mites at both the molecular and physiological *** study offers a promising possibility that combines the compatible biocontrol agents of Xcn1 and predatory mites for integrated pest mite control.

关键词： pest management predatory mite Xcn1 morphology developmental inhibition transcriptome

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Distribution of oxide inclusions in H13 castings under super-gravity field with multi-stage rotation speeds

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Journal of Iron and Steel Research International 2024年第1期31卷 121-133页

作者： Shao-ying li Xiao-jun Xi Xing-ming Zhao Han-jie Guo Jing Guo School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing100083China Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials Beijing100083China Beijing Beiye Functional Materials Corporation Beijing100192China Shandong Tianwu Forming Technology Co. Ltd.Liaocheng252024ShandongChina

The 42 kg industrial H13 castings were prepared by different super-gravity fields with multi-rotation speeds,and the distribution of oxide inclusions in the castings was *** addition,the inward movement Reynolds number and inward movement time of oxide inclusions as well as the solidification time of molten steel at different positions in the castings were calculated to clarify the removal mechanism of oxide inclusions in super-gravity *** results show that the large size(i.e.,greater than 10μm)oxide inclusions are mainly concentrated in the inner and outer parts of the super-gravity castings with constant rotation speed(500 r min^(-1))and five-stage rotation speeds(500,600,750,850,and 950 r min^(-1)),respectively,while there are no large oxide inclusions in the super-gravity castings with three-stage rotation speeds(500,600,and 750 r min^(-1)).Although an increase in the particle size of inclusion and the rotation speed in super-gravity field is conducive to the increase in the inward movement Reynolds number of oxide inclusions and reduction in the inward movement time of oxide inclusions,it will reduce the local solidification time of molten *** the range of the rotation speed studied,the super-gravity field with three-stage rotation speeds has the best effect on the removal of inclusions in H13 molten steel.

关键词： Distribution Oxide inclusion H13 casting Super-gravity field Rotation speed

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Integrating machine learning and CALPHAD method for exploring low-modulus near-β-Ti alloys

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Rare Metals 2024年第1期43卷 309-323页

作者： Hao Zou Yue-Yan Tian li-Gang Zhang ren-Hao Xue Zi-Xuan Deng ming-ming Lu Jian-Xin Wang li-Bin liu School of Computer Science and Engineering Central South UniversityChangsha 410083China School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

Traditional theoretical and empirical calculation methods can guide the design of β-and metastable β-alloys for bio-titanium. However, it is still difficult to obtain novel near-β-Ti alloys with low modulus. This study developed a method that combines machine learning with calculation of phase diagrams(CALPHAD) to facilitate the design of near-β-Ti alloys. An elastic modulus database of Ti–Nb–Zr–Mo–Ta–Sn system was constructed first, and then three features(the electron to atom ratio, mean absolute deviation of atom mass, and mean electronegativity) were selected as the key factors of modulus by performing a three-step feature selection. With these features, a highly accurate model was built for predicting the modulus of near-β-Ti alloys. To further ensure the accuracy of modulus prediction, machine learning with the elastic constants calculated was leveraged by CALPHAD database. The root mean square error of the well-trained model can be as low as 6.75 GPa. Guided by the prediction of machine learning and CALPHAD, three novel near-β-Ti alloys with elastic modulus below 50 GPa were successfully designed in this study. The best candidate alloy(Ti–26Nb–4Zr–4Sn–1Mo–Ta) exhibits an ultra-low modulus(36.6 GPa) after cold rolling with a thickness reduction of 20%. Our method can greatly save time and resources in the development of novel Ti alloys, and experimental verifications have demonstrated the reliability of this method.

关键词： Near-β-Ti alloy Machine learning Calculation of phase diagram Low-modulus alloy Feature selection

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Apically guiding electron/mass transfer reaction induced by Ag/FeN_(x)Mott-Schottky effect within a hollow star reactor toward high performance zinc-air batteries

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Journal of Energy Chemistry 2024年第8期95卷 106-116,I0004页

作者： Kaixiang Shi Kaixin Wang Tong li Junhao li jie ren Xu li Yonggang Min Zhouguang Lu Wei Tan Quanbing liu Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering jieyang Center(Rongjiang Laboratory) Guangdong University of TechnologyJieyang 515200GuangdongChina Guangzhou Key Laboratory of Clean Transportation Energy Chemistry Guangdong Provincial Key Laboratory of Plant Resources BiorefinerySchool of Chemical Engineering and Light IndustryGuangdong University of TechnologyGuangzhou 510006GuangdongChina Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province School of Chemistry and Chemical EngineeringHainan Normal UniversityHaikou 571158HainanChina School of Materials and Energy Guangdong University of TechnologyGuangzhou 510006GuangdongChina Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055GuangdongChina

The disparity in the transfer of carriers(electrons/mass)during the reaction in zinc-air batteries(ZABs)results in sluggish kinetics of the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),along with elevated overpotentials,thereby imposing additional constraints on its ***,the pre-design and target-development of inexpensive,high-performance,and long-term stable bifunctional catalysts are urgently *** this work,an apically guiding dual-functional electrocatalyst(Ag-FeN_(x)-N-C)was prepared,in which a hierarchical porous nitrogen-doped carbon with three-dimensional(3D)hollow star-shaped structure is used as a substrate and high-conductivity Ag nanoparticles are coupled with iron nitride(FeN_(x))*** calculations indicate that the Mott-Schottky heterojunction as an inherent electric field comes from the two-phase bound of Ag and FeN_(x),of which electron accumulation in the FeN_(x)phase region and electron depletion in the Ag phase region promote orientated-guiding charge *** effective modulation of local electronic structures felicitously reforms the d-band electron-group distribution,and intellectually tunes the masstransfer reaction energy barriers for both ORR/***,the hollow star-s haped hierarchical porous structure provides an apical region for fast mass *** results show that the halfwave potential for ORR is 0.914 V,and the overpotential for OER is only 327 mV at 10 mA cm^(-2).A rechargeable ZAB with Ag-FeN_(x)-N-C as the air cathode demonstrates long-term cycling performance exceeding 1500 cycles(500 h),with a power density of 180 mW cm^(-2).Moreover,when employing AgFeN_(x)-N-C as the air cathode,flexible ZABs demonstrate a notable open-circuit voltage of 1.42 V and achieve a maximum power density of 65.6 mW cm^(-2).Ag-FeN_(x)-N-C shows guiding electron/mass transfer route and apical reaction microenvironment for the electrocatalyst architecture in the explo

关键词： Hollow star structure Mott-Schottky effect Apically guiding effect Bifunctional catalysis Zinc-air batteries

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