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Chinese Physics C 2010年第5期34卷 565-570页

作者：岳骞李元景叶瑾程建平王义李金吴昱城 department of engineering Physics Tsinghua University Key Laboratory of Particle & radiation Imaging Tsinghua University

The effects of surface resistivity of the high voltage provider on the space dispersion of the induced charge of a prototype Resistive Plate Chamber （RPC） have been studied experimentally and theoretically. The results of both experiment and theory agree and confirm that a two-Gaussian function can be used to fit the dispersion of the induced charge of the RPC. It is shown that the Gaussian function with the narrower width is mainly due to the expansion of the avalanche charge in the gas gap of the RPC, and the Gaussian function with the larger width is due to the charge dispersion when it passes through the resistive carbon film. This will be useful in the RPC design when one wants to make an RPC with high position resolution.

关键词： RPC surface resistivity avalanche size position resolution

An industrial CT system for monitoring a running aero-engine

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Nuclear Science and Techniques 2014年第6期25卷 24-30页

作者：常铭肖永顺陈志强 department of engineering Physics Tsinghua University Key Laboratory of Particle & radiation Imaging Tsinghua University

In order to improve aerodynamic performance and efficiency, monitoring the geometry and position information of the internal structure with the aero-engine under various operational statuses is an important task. In this paper, a novel design of industrial computed tomography(ICT) system with a linac as X-ray source is proposed to complete the task. The major advantage of the proposed system is that it can provide visualized images of internal structures of the running aero-engine without physical disturbance, which makes it possible to extract the accurate geometry information. The main idea behind this design is to measure the projection data from various views for reconstructions making use of the rotations of the aero-engine blades, instead of the mechanical rotations in the conventional ICT system. However, due to high speed rotation of the aero-engine blades,the system faces more challenges than conventional ICT systems both in data acquisitions and reconstruction algorithms. The challenges and corresponding solutions are presented in this paper. In conclusion, the proposed ICT system provides a powerful tool for monitoring the running aero-engines.

关键词：航空发动机叶片工业CT系统运行工业计算机断层扫描空气动力性能信息通信系统内部结构线性加速器

Studies on mass attenuation coefficients for some body tissues with different medical sources and their validation using Monte Carlo codes

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Nuclear Science and Techniques 2020年第12期31卷 50-64页

作者： Sepideh Yazdani Darki Sajad Keshavarz department of Physics University of YazdYazdIran department of Medical radiation engineering University of Science and Research Branch TehranTehranIran

The mass attenuation coefficients of the breasts,lungs,kidneys,pancreas,liver,eye lenses,thyroid,brain,ovary,heart,large intestines,blood,skin,spleen,muscle,and cortical bone were measured at different sources(i.e.,0.021,0.029,0.03,0.14,0.218,0.38,0.412,0.663,0.83,and 1.25 MeV)using various methods including the Monte Carlo N-particle transport code(MCNP),the geometry and tracking code(GEANT4),and theoretical approach described in this *** attenuation coefficients were also compared with the values from the national institute of standards and technology(NIST-XCOM).The values obtained were similar to those obtained using *** results show that the theoretical method is quite convenient in comparison with GEANT4 and MCNP in the calculation of the mass attenuation coefficients of the human body samples applied when compared with the NIST values and demonstrated an acceptable difference.

关键词： Mass attenuation coefficient MCNP Geant4 XCOM Human organs

Gradient‑Layered MXene/Hollow Lignin Nanospheres Architecture Design for Flexible and Stretchable Supercapacitors

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Nano-Micro Letters 2025年第2期17卷 447-462页

作者： Haonan Zhang Cheng Hao Tongtong Fu Dian Yu Jane Howe Kaiwen Chen Ning Yan Hao Ren Huamin Zhai Jiangsu Provincial Key Lab of Sustainable Pulp and Paper Technology and Biomass Materials NanJing Forestry UniversityNanjing 210037People’s Republic of China department of Chemical engineering and Applied Chemistry University of Toronto200 College StreetTorontoON M5S 3E5Canada department of Materials Science and engineering University of Toronto184 College StreetTorontoON M5S 3E4Canada College of Materials Science and engineering Nanjing Forestry UniversityNanjing 210037People’s Republic of China

With the rapid development of flexible wearable electronics,the demand for stretchable energy storage devices has *** this work,a novel gradient-layered architecture was design based on single-pore hollow lignin nanospheres(HLNPs)-intercalated two-dimensional transition metal carbide(Ti_(3)C_(2)T_(x) MXene)for fabricating highly stretchable and durable *** depositing and inserting HLNPs in the MXene layers with a bottom-up decreasing gradient,a multilayered porous MXene structure with smooth ion channels was constructed by reducing the overstacking of MXene ***,the micro-chamber architecture of thin-walled lignin nanospheres effectively extended the contact area between lignin and MXene to improve ion and electron accessibility,thus better utilizing the pseudocapacitive property of *** these strategies effectively enhanced the capacitive performance of the *** addition,HLNPs,which acted as a protective phase for MXene layer,enhanced mechanical properties of the wrinkled stretchable electrodes by releasing stress through slip and deformation during the stretch-release cycling and greatly improved the structural integrity and capacitive stability of the *** electrodes and symmetric flexible all-solid-state supercapacitors capable of enduring 600%uniaxial tensile strain were developed with high specific capacitances of 1273 mF cm^(−2)(241 F g^(−1))and 514 mF cm^(−2)(95 F g^(−1)),***,their capacitances were well preserved after 1000 times of 600%stretch-release *** study showcased new possibilities of incorporating biobased lignin nanospheres in energy storage devices to fabricate stretchable devices leveraging synergies among various two-dimensional nanomaterials.

关键词： Hollow lignin nanospheres MXene Gradient-layered architecture Wrinkled electrodes Stretchable supercapacitors

Spin-glass behavior in the competing CoCrGaO_(4)cubic spinel system

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Nano Research 2025年第1期18卷 501-507页

作者： Jiyu Hu Jiangli Ni Zhenfa Zi Chaocheng Liu School of Physics and Materials engineering Hefei Normal UniversityHefei 230009China National Synchrotron radiation Laboratory University of Science and Technology of ChinaHefei 230026China

Spin glasses(SGs),generally defined as disordered systems with randomized competing interactions,are widely investigated complex *** the ground states of spin glasses is crucial for understanding the nature of disordered magnets and many other physical manifestations,while also helping to solve some hard combinatorial optimization problems across multiple ***,the intrinsic cause of SG has always been elusive,especially in spinel oxide ***,we report the SG behavior observed in the cubic spinel oxides CoCrGaO_(4),and provide a comprehensive understanding of its intrinsic *** results indicate a frustrated state under multi-magnetic competition,and the features of SG are confirmed by susceptibility *** fitting parameters ofτ0,T0,and zv of isothermal remanent magnetization further reveal the relaxation behavior and strong spin ***,the varying exchange coupling under different temperatures and magnetic fields is unveiled,which should be responsible for the disordered *** studies unravel the underlying mechanism responsible for doping-induced magnetic frustration and introduce CoCrGaO_(4)as a potential platform for investigating spin glass behavior,thereby advancing fundamental research on frustrated magnetism within the spinel system.

关键词： spin glass(SG) magnetic frustration magnetic competition spinel ferrites

Modification of TiN Coatings by N^(+) and C^(+) Implantation with High Ion Flux

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Chinese Physics Letters 1999年第3期16卷 196-198页

作者： ZHANG Tong-he WU Yu-guang ZHAO Zhi-yong DENG Zhi-wei Institute of Low Energy Nuclear Physics Radiation Beam and Materials Engineering Open Laboratory of Department of Education of ChinaBeijing Radiation CenterBeijing Normal UniversityBeijing 100875

The TiN coating changed from columnar structure to compact texture after N^(+)and C^(+)implantation.X-ray analysis showed that combining with N atoms,Ti and Ti_(2)N would be transformed into TiN Phases during N *** ternary solid solution mixtures TiCN have been formed,while Ti,Ti_(2)N would be transformed into TiC and TiCN phases combining with C atoms after C *** hardness of the TiN coating increased by 2.3-2.4 times after N^(+)or C^(+)*** wear resistance of implanted TiN coatings is 2-3 times higher than that of unimplanted TiN *** the drills were treated with the method,their lifetime would increase by 7 times comparing with unimplanted *** an attractive procedure,the ion implantation of the TiN coatings would find new applications in many fields.

关键词： coating wear resistance

Twin image removal in X-ray fluorescence holography with two energies

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Chinese Physics C 2008年第12期32卷 1016-1020页

作者：陈淼鑫李政 Key Laboratory of Particle & radiation Imaging (Tsinghua University) Ministry of EducationDepartment of Engineering Physics Tsinghua University

In the last decade, X-ray fluorescence holography has been developed for the study of 3D atomic arrangements in solids. However, it encounters the twin image problem which may disturb the reconstructed atomic images. In this paper, the formation of twin image is discussed and we propose a modified two-energy algorithm to remove the twin image. The simulation shows that the method is valid and more efficient than the multiple-energy algorithm proposed by Barton.

关键词： X-ray holography twin image

Tuning the interfacial reaction environment via pH-dependent and induced ions to understand C–N bonds coupling performance in NO3- integrated CO2 reduction to carbon and nitrogen compounds over dual Cu-based N-doped carbon catalyst

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Journal of Energy Chemistry 2025年第1期100卷 273-285页

作者： Tianhang Zhou Chen Shen Zhenghao Wu Xingying Lan Yi Xiao College of Carbon Neutrality Future Technology State Key Laboratory of Heavy Oil Processing China University of Petroleum (Beijing) Institute of Materials Science TU Darmstadt department of Chemistry Xi'an Jiaotong-Liverpool University department of Mechanical and Mechatronics engineering and Waterloo Institute of Nanotechnology University of Waterloo Waterloo

Dual atomic catalysts （DAC）,particularly copper （Cu2）-based nitrogen （N） doped graphene,show great potential to effectively convert CO2and nitrate （NO3-） into important industrial chemicals such as ethylene,glycol,acetamide,and urea through an efficient catalytical process that involves C–C and C–N ***,the origin of the coupling activity remained unclear,which substantially hinders the rational design of Cu-based catalysts for the N-integrated CO2reduction reaction （CO2RR）.To address this challenge,this work performed advanced density functional theory calculations incorporating explicit solvation based on a Cu2-based N-doped carbon (Cu2N6C10) catalyst for *** calculations are aimed to gain insight into the reaction mechanisms for the synthesis of ethylene,acetamide,and urea via coupling in the interfacial reaction *** to the sluggishness of CO2,the formation of a solvation electric layer by anions （F-,Cl-,Br-,and I-） and cations (Na+,Mg2+,K+,and Ca2+) leads to electron transfer towards the Cu *** process significantly accelerates the reduction of *** results reveal that*CO intermediates play a pivotal role in N-integrated ***,the Cu2-based N-doped carbon catalyst examined in this study has demonstrated the most potential for C–N coupling to *** findings reveal that through the process of a condensation reaction between*CO and NH2OH for urea synthesis,*NO3-is reduced to*NH3,and*CO2to*CCO at dual Cu atom *** dual-site reduction facilitates the synthesis of acetamide through a nucleophilic reaction between NH3and the ketene ***,we found that the I-and Mg2+ions,influenced by pH,were highly effective for acetamide and ammonia synthesis,except when F-and Ca2+were ***,the mechanisms of C–N bond formation were investigated via ab-initio molecular dynamics simulations,and we found that adjusting the micro-environment can change the dominant side reaction,shift

关键词： pH-dependent micro-environments C–N coupling Dual Cu-based nitrogen carbon catalysts Explicit solvation model Ion stabilizer AIMD

Characterization of a broad-energy germanium detector for its use in CJPL

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Nuclear Science and Techniques 2017年第1期28卷 42-48页

作者： Zhi Zeng Yu-Hao Mi Ming Zeng Hao Ma Qian Yue Jian-Ping Cheng Jun-Li Li Rui Qiu Hui Zhang Key Laboratory of Particle and radiation Imaging (Ministry of Education) and department of engineering Physics Tsinghua University Beijing 100084 China

The broad-energy germanium(BEGe)detector,with the ability of background discrimination using pulse shape discrimination,is a competitive candidate for neutrinoless double beta decay(ovββ)*** this paper,we report our measurements of key parameters for detector modeling in a commercial p-type BEGe ***-like sources are used to investigate energy resolution and linearity of the detector.A cylindrical volume source is used for efficiency *** an assembled device for source positioning and a collimated ^(133)Ba source,the detector is scanned to check its active *** an^(241)Am point-like source,the dead layer thicknesses is measured at about 0.17 mm on the front and 1.18 mm on the *** detector characterization is of importance for BEGe detectors to be used in the ovββ experiments at China JinPing underground Laboratory(CJPL).

关键词： BEGe Characterization Dead layer 0mbb CJPL

A Low-Cost Dual Energy CT System with Sparse Data

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Tsinghua Science and Technology 2014年第2期19卷 184-194页

作者： Yuanyuan Liu Jianping Cheng Li Zhang Yuxiang Xing Zhiqiang Chen Peng Zheng Nuclear and radiation Safety Center Ministry of Environmental Protection of China department of engineering Physics Tsinghua University

Dual Energy CT （DECT） has recently gained significant research interest owing to its ability to discriminate materials, and hence is widely applied in the field of nuclear safety and security inspection. With the current technological developments, DECT can be typically realized by using two sets of detectors, one for detecting lower energy X-rays and another for detecting higher energy X-rays. This makes the imaging system expensive, limiting its practical implementation. In 2009, our group performed a preliminary study on a new low-cost system design, using only a complete data set for lower energy level and a sparse data set for the higher energy level. This could significantly reduce the cost of the system, as it contained much smaller number of detector elements. Reconstruction method is the key point of this system. In the present study, we further validated this system and proposed a robust method, involving three main steps：（1） estimation of the missing data iteratively with TV constraints; （2） use the reconstruction from the complete lower energy CT data set to form an initial estimation of the projection data for higher energy level; （3） use ordered views to accelerate the computation. Numerical simulations with different number of detector elements have also been examined. The results obtained in this study demonstrate that 1 ＋ 14% CT data is sufficient enough to provide a rather good reconstruction of both the effective atomic number and electron density distributions of the scanned object, instead of 2 sets CT data.

关键词： X-ray imaging dual energy CT system sparse samples reconstruction material discriminationAR^TV