检索结果-南通市图书馆

Evaluation of the passivation effect and the first-principles calculation on surface termination of germanium detector

引用

Nuclear Science and Techniques 2021年第9期32卷 40-51页

作者： sha-sha lv Yuan-Yuan Liu Wei-You Tang Li He Xiu-Xia Li Jian-Ping Cheng Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Department of Engineering Physics Tsinghua UniversityBeijing 100084China Joint Research Center Nuctech Company LimitedBeijing 100084China

The point-contact high-purity germanium detector(HPGe)has the advantages of low background,low energy threshold,and high energy resolution and can be applied in the detection of rare-event ***,the performance of HPGe must be further improved to achieve superior energy resolution,low noise,and long-term *** this study,we combine computational simulations and experimental comparisons to deeply understand the passivation mechanism of *** surface passivation effect is calculated and inferred from the band structure and density of interface states,and further con-firmed by the minority carrier *** first-principles method based on the density functional theory was adopted to systematically study the lattice structure,band structure,and density of state(DOS)of four different systems:Ge–H,Ge–Ge-NH 2,Ge-OH,and Ge-SiO_(x).The electronic char-acteristics of the Ge(100)unit cell with different passi-vation groups and Si/O atomic ratios were *** shows that H,N,and O atoms can effectively reduce the surface DOS of the Ge *** passivation effect of the SiO_(x) group varied with increasing O atoms and Si/O atomic ***,SiO and SiO_(2) passivation films were fabricated by electron beam evaporation on a Ge substrate,and the valence state of Si and resistivity was measured to characterize the *** minority carrier lifetime of Ge-SiO_(2) is 21.3 ls,which is approximately quadruple that of *** passivation effect and mechanism are discussed in terms of hopping conduction and surface defect *** study builds a relationship between the passivation effect and different termination groups,and provides technical support for the potential passivation layer,which can be applied in Ge detectors with ultralow energy thresholds and especially in HPGe for rare-event physics detection experiments in future.

关键词： Germanium detector Passivation Surface termination

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Static and dynamic evolution of CO adsorption onγ-U(100)surface with different levels of Mo doping using DFT and AIMD calculations

引用

Nuclear Science and Techniques 2023年第9期34卷 142-154页

作者： Jun-Wei Li Wei-Min Jia Chong Liu sha-sha lv Jin-Tao Wang Zheng-Cao Li Key Lab of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Xi’an Research Institute of High-Technology Xi’an 710025China Key Laboratory of Beam Technology(MOE) College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China

Alloys of uranium and molybdenum are considered as the future of nuclear fuel and defense ***,surface corrosion is a fundamental problem in practical applications and *** this study,the static and dynamic evolution of carbon monoxide(CO)adsorption and dissociation onγ-U(100)surface with different Mo doping levels was investigated based on density functional theory and ab initio molecular *** the static calculation phase,parameters,such as adsorption energy,configuration,and Bader charge,were evaluated at all adsorption ***,the time-dependent behavior of CO molecule adsorption were investigated at the most favorable *** minimum energy paths for CO molecu-lar dissociation and atom migration were investigated using the transition state search *** results demonstrated that the CO on the uranium surface mainly manifests as chemical adsorption before dissociation of the CO *** CO molecule exhibited a tendency to rotate and tilt upright ***,it is difficult for CO adsorption on the surface in one of the configurations with CO molecule in vertical direction but oxygen(O)is closer to the *** charge illustrates that the charge transfers from slab atoms to the 2π*antibonding orbital of CO molecule and particularly occurs in carbon(C)*** time is less than 100 fs for the adsorptions that forms embryos with tilt upright in dynamics *** density of states elucidates that the overlapping hybridization of C and O 2p orbitals is mainly formed via the d orbitals of uranium and molybdenum(Mo)atoms in the dissociation and re-adsorption of CO *** conclusion,Mo doping of the surface can decelerate the adsorption and dissociation of CO molecules.A Mo-doped surface,created through ion injection,enhanced the resistance to uranium-induced surface corrosion.

关键词： Adsorption and dissociation Uranium CO molecule Density functional theory Ab initio molecular dynamics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

OKMC simulation of vacancy-enhanced Cu solute segregation affected by temperature/irradiation in the Fe–Cu system

引用

Nuclear Science and Techniques 2022年第11期33卷 158-169页

作者： Zi-Qin Shen Jie Gao sha-sha lv Liang Chen Dong-Yue Chen De-Sheng Ai Zheng-Cao Li Key Lab of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Nuclear and New Energy Institute Tsinghua UniversityBeijing 100084China Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Beam Technology Ministry of EducationCollege of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Nuclear Engineering and Management The University of TokyoTokyo 113-8656Japan

The effects of annealing and irradiation on the evolution of Cu clusters in a-Fe are investigated using object kinetic Monte Carlo *** our model,vacancies act as carriers for chemical species via thermally activated diffusion jumps,thus playing an important role in solute *** the end of the Cu cluster evolution,the simulations of the average radius and number density of the clusters are consistent with the experimental data,which indicates that the proposed simulation model is applicable and *** the simulation of the annealing process,it is found that the evolution of the cluster size roughly follows the 1/2 time power law with the increase in radius during the growth phase and the 1/3 time power law during the coarsening *** addition,the main difference between neutron and ion irradiation is the growth and evolution process of the copper-vacancy *** aggregation of vacancy clusters under ion irradiation suppresses the migration and coarsening of the clusters,which ultimately leads to a smaller average radius of the copper *** proposed simulation model can supplement experimental analyses and provide a detailed evolution mechanism of vacancy-enhanced precipitation,thereby providing a foundation for other elemental precipitation research.

关键词： Object kinetic Monte Carlo Irradiation effect Solute segregation Reactor pressure vessel

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Numerical study of liquid coverage in a gas-liquid-solid packed bed

引用

Particuology 2015年第6期13卷 90-99页

作者： Wei Du Lifeng Zhang sha lv Panpan Lu Jian xu Weisheng Wei State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing 102249 China The Key Laboratory of Catalysis China National Petroleum Corp. China University of Petroleum Beijing 102249 China Department of Chemical and Biological Engineering University of Saskatchewan Saskatoon SK Canada

In this work, computational fluid dynamics （CFD） simulations using the volume-of-fluid （VOF） model were employed to investigate the effects of liquid properties, liquid and gas flow rates, and wettability of particles on liquid maldistribution at the microscopic level in a fixed bed reactor. The simulation results show that the number of wetted particles decreases with increasing gas velocity, consequently leading to lower liquid-solid contact areas. The radial liquid distribution is greatly enhanced by increasing the liquid flow rate, whereas the time for the liquid to pass through the whole bed is decreased, as expected. Based on simulation results, it was found that the liquid-solid contact area can be increased by using liquids of high viscosities and more wettable particles. However, the flow-through time increases with increasing liquid viscosity. An increase in the gas density showed a minimal impact on the liquid flow- through time, and the liquid density does not impact the radial liquid distribution or the liquid flow time within a range of liquid densities typically encountered in the petrochemical industry.

关键词： CFD VOF Liquid-solid contact area Radial liquid distribution Fixed bed

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Surface metallization of PTFE and PTFE composites by ion implantation for low-background electronic substrates in rare-event detection experiments

引用

Nuclear Science and Techniques 2022年第7期33卷 37-47页

作者： shao-Jun Zhang Yuan-Yuan Liu sha-sha lv Jian-Ping Cheng Bin Liao Pan Pang Zhi Deng Li He College of Nuclear Science and Technology Beijing Normal UniversityJoint Laboratory of Jinping Ultra-low Radiation Background Measurement of Ministry of Ecology and Environment Beijing Normal UniversityKey Laboratory of Beam Technology of Ministry of EducationBeijing Normal UniversityBeijing100875China Beijing Radiation Center Beijing100875China Department of Engineering Physics Key Laboratory of Particle and Radiation Imaging of Ministry of EducationTsinghua UniversityBeijing100084China Joint Research Center Nuctech Company LimitedBeijing100084China

Polytetrafluoroethylene(PTFE)is a low-background polymer that is applied to several applications in rare-event detection and underground low-background ***-based electronic substrates are important for reducing the detection limit of high-purity germanium detectors and scintillator calorimeters,which are widely applied in dark matter and 0υββdetection *** traditional adhesive bonding method between PTFE and copper is not conducive to working in liquid nitrogen and extremely low-temperature *** avoid adhesive bonding,PTFE must be processed for surface metallization owing to the mismatch between the PTFE and copper conductive ***-background PTFE matrix composites(m-PTFE)were selected to improve the electrical and mechanical properties of PTFE by introducing SiO_(2)/TiO_(2) *** microstructures,surface elements,and electrical properties of PTFE and m-PTFE were characterized and analyzed following ion *** and m-PTFE surfaces were found to be broken,degraded,and cross-linked by ion implantation,resulting in C=C conjugated double bonds,increased surface energy,and increased surface ***,the surface roughness,bond strength,and conjugated double bonds of m-PTFE were significantly more intense than those of ***,the interface bonding theory between PTFE and the metal copper foil was analyzed using the direct metallization ***,the peel strength of the optimized electronic substrates was higher than that of the industrial standard at extremely low temperatures,while maintaining excellent electrical properties.

关键词： Surface modification Polytetrafluoroethylene Ion implantation Surface metallization Low temperature resistance

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Evolution of helium bubbles in nickel-based alloy by post-implantation annealing

引用

Chinese Physics B 2021年第8期30卷 55-60页

作者： Rui Zhu Qin Zhou Li Shi Li-Bin Sun Xin-Xin Wu sha-sha lv Zheng-Cao Li Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China Key Laboratory of Advanced Materials(Ministry of Education) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Key Laboratory of Beam Technology Ministry of EducationCollege of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China

Nickel-based alloys have been considered as candidate structural materials used in generation IV nuclear reactors serving at high *** the present study,alloy 617 was irradiated with 180-keV helium ions to a fluence of 3.6×10^(17) ions/cm^(2) at room *** the cross-section transmission electron microscopy(TEM)image,numerous over-pressurized helium bubbles in spherical shape are observed with the actual concentration profile a little deeper than the SRIM predicted ***-implantation annealing was conducted at 700℃for 2 h to investigate the bubble *** long-range migration of helium bubbles occurred during the annealing process,which makes the bubbles of the peak region transform into a faceted shape as *** the coarsening mechanism of helium bubbles at different depths is discussed and related to the migration and coalescence(MC)*** the diffusion of nickel atoms slowed down by the alloy elements,the migration and coalescence of bubbles are suppressed in alloy 617,leading to a better helium irradiation resistance.

关键词： helium bubble coarsening mechanism nickel-based alloy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Analysis of Etiology,Diagnosis,and Treatment Strategy and Efficacy of Pulsatile Tinnitus Caused by Abnormal Vascular Anatomy

引用

Current Medical Science 2023年第1期43卷 173-183页

作者： sha lv Jia-tian YUAN Qi-wei XIE Shi-xiong TANG Yao-wen WANG Department of Otolaryngology Ningbo First HospitalNingbo315000China

Objective To investigate the etiology,clinical characteristics,diagnosis,and treatment strategies and efficacy of pulsatile tinnitus(PT)caused by vascular anatomy *** The clinical data of 45 patients with PT in our hospital from 2012 to 2019 were collected and retrospectively *** All 45 patients had vascular anatomical *** patients were divided into 10 categories according to the different locations of vascular abnormalities:sigmoid sinus diverticulum(SSD),sigmoid sinus wall dehiscence(SSWD),SSWD with high jugular bulb,pure dilated mastoid emissary vein,aberrant internal carotid artery(ICA)in the middle ear,transverse-sigmoid sinus(TSS)transition stenosis,TSS transition stenosis with SSD,persistent occipital sinus stenosis,petrous segment stenosis of ICA,and dural arteriovenous *** patients complained of PT synchronous with heartbeat *** interventional therapy and extravascular open surgery were used according to the location of the vascular *** disappeared in 41 patients,was significantly relieved in 3 patients,and was unchanged in 1 patient *** for one patient with transient headache postoperatively,no obvious complications *** PT caused by vascular anatomy abnormalities can be identified by detailed medical history and physical and imaging *** can be relieved or even completely alleviated after appropriate surgical treatments.

关键词： pulsatile tinnitus vessel structural abnormity etiology treatment strategy efficacy

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Analyzing the surface passivity effect of germanium oxynitride:a comprehensive approach through first principles simulation and interface state density

引用

Nuclear Science and Techniques 2024年第5期35卷 74-84页

作者： Sheng-Jie Du Xiu-Xia Li Yang Tian Yuan-Yuan Liu Ke Jia Zhong-Zheng Tang Jian-Ping Cheng Zhi Deng Yu-Lan Li Zheng-Cao Li sha-sha lv College of Nuclear Science and Technology Joint Laboratory of Jinping Ultra‑Low Radiation Background Measurement of Ministry of Ecology and Environment Key Laboratory of Beam Technology of Ministry of Education Beijing Normal UniversityBeijing Normal UniversityBeijing 100875China Joint Research Center Nuctech Company LimitedBeijing 100084China Department of Engineering Physics Key Laboratory of Particle&Radiation Imaging of Ministry of EducationTsinghua UniversityBeijing 100084China Key Laboratory of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

High-purity germanium(HPGe)detectors,which are used for direct dark matter detection,have the advantages of a low threshold and excellent energy *** surface passivation of HPGe has become crucial for achieving an extremely low energy *** this study,first-principles simulations,passivation film preparation,and metal oxide semiconductor(MOS)capacitor characterization were combined to study surface *** calculations of the energy band structure of the -H,-OH,and -NH_(2) passivation groups on the surface of Ge were performed,and the interface state density and potential with five different passivation groups with N/O atomic ratios were accurately analyzed to obtain a stable surface *** on the theoretical calculation results,the surface passivation layers of the Ge_(2)ON_(2) film were prepared via magnetron sputtering in accordance with the optimum atomic ratio *** microstructure,C-V,and I-V electrical properties of the layers,and the passivation effect of the Al/Ge_(2)ON_(2)/Ge MOS were characterized to test the interface state *** mean interface state density obtained by the Terman method was 8.4×10^(11) cm^(-2) eV^(-1).The processing of germanium oxynitrogen passivation films is expected to be used in direct dark matter detection of the HPGe detector surface passivation technology to reduce the detector leakage currents.

关键词： Surface passivation High purity germanium detector Germanium nitrogen oxide Interface state density

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of Substrate Pulse Bias Duty Cycle on the Microstructure and Mechanical Properties of Ti–Cu–N Films Deposited by Magnetic Field-Enhanced Arc Ion Plating

引用

Acta Metallurgica Sinica(English Letters) 2017年第2期30卷 176-184页

作者： Sheng-Sheng Zhao Yan-Hui Zhao lv-sha Cheng Vladimir Viktorovich Denisov Nikolay Nikolaevich Koval Bao-Hai Yu Hai-Juan Mei School of Mechanical and Electrical Engineering Shenzhen Polytechnic Institute of Metal Research Chinese Academy of Sciences Institute of High Current Electronics Siberian BranchRussian Academy of Sciences

Ti–Cu–N films were deposited on 316 L stainless steel substrates by magnetic field-enhanced arc ion *** effect of substrate pulse bias duty cycle on the chemical composition,microstructure,surface morphology,mechanical and tribological properties of the films was systemically *** results showed that,with increasing the duty cycle,Cu content decreases from 3.3 to 0.58 at.%.XRD results showed that only Ti N phase is observed for all the deposited films and the preferred orientation transformed from Ti N（200） to Ti N（111） plane with the increase in duty *** surface roughness and deposition rate showed monotonous decrease with increasing the duty *** residual stress and hardness firstly increase and then decrease afterwards with the increase in duty cycle,while the variation of critical load shows reverse *** for the film with duty cycle of 10%,others perform the better wear resistance.

关键词： Magnetic field Arc ion plating Ti-Cu-N film Residual stress Hardness

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Itraconazole therapy for infant hemangioma:Two case reports

引用

World Journal of Clinical Cases 2021年第28期9卷 8579-8586页

作者： Zhe Liu sha lv Shuang Wang Sheng-Ming Qu Gui-Yun Zhang Yi-Tong Lin Lei Yang Fu-Qiu Li Department of Dermatology The Second Hospital of Jilin UniversityChangchun 130041Jilin ProvinceChina

BACKGROUND Infantile hemangiomas(IHs)are the most common childhood benign tumors,showing distinctive progression characteristics and *** to the high demand for aesthetics among parents of IH babies,early intervention is critical in some cases.β-Adrenergic blockers and corticosteroids are first-line medications for IHs,while itraconazole,an antifungal medicine,has shown positive results in recent *** SUMMARY In the present study,itraconazole was applied to treat two IH *** therapeutic course lasted 80-90 d,during which the visible lesion faded by more than 90%.Moreover,no obvious side effects were reported,and the compliance of the baby and parents was *** Although these outcomes further support itraconazole as an effective therapeutic choice for IHs,large-scale clinical and basic studies are still warranted to improve further treatment.

关键词： Infant Hemangiomas Therapeutics Itraconazole Oral Case report

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：