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AMS-(14)C样品制备系统的研制及其性能研究

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同位素 2021年第3期34卷 273-281页

作者：亓明丽李昭梅唐俊森魏思雨刘明吉赵振池石书林 kimikazu sasa 沈洪涛广西师范大学物理科学与技术学院广西桂林541004 日本筑波大学应用加速器中心日本茨城305-8577 广西核物理与核技术重点实验室广西桂林541004

为了开展加速器质谱仪(accelerator mass spectrometry, AMS)在(14)C测量方面的研究,研制了可采用锌法、氢法、氢化钛法制备(14)C样品的装置,该制样系统以石英玻璃为主要结构材料,分为以下三个单元:系统真空维护单元、CO_(2)纯化单元和C... 详细信息

为了开展加速器质谱仪(accelerator mass spectrometry, AMS)在(14)C测量方面的研究,研制了可采用锌法、氢法、氢化钛法制备(14)C样品的装置,该制样系统以石英玻璃为主要结构材料,分为以下三个单元:系统真空维护单元、CO_(2)纯化单元和CO_(2)还原单元。为验证此装置的可靠性,进行了系列(14)C样品的制备实验,得到的石墨产率基本达到80%,同时对商业碳粉、树木的含碳量与实验过程中测量区域对应的CO_(2)量进行了线性拟合,结果呈现明显的线性关系。对一批标准样品和本底样品进行AMS测试,结果显示每个样品(12)C-的引出束流均大于20μA,系列空白样品的测量结果表明,^(14)C/^(12)C丰度比平均值为1.061×10^(-15),样品制备系统稳定且在制样过程中引入的碳污染较小,符合制样要求,现代木头样品的AMS绝对测量值为(9.13±0.05)×10^(-13),与预期值~9.0×10^(-13)相符合。上述结果表明,该系统结构紧凑,能避免相互污染,高效且便于操作,满足AMS对(14)C样品的测试要求。

关键词： ^(14)C样品制备 ^(14)C 加速器质谱

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加速器质谱测量^(129)Ⅰ方法的改进

核电子学与探测技术 2007年第4期27卷 740-744页

作者：周本胡長島泰夫姜山吴伟明管永精武绍勇何明袁坚阮向东関李紀笹公和高橋努崎裕貴松四雄騎玉理美智子末木啓介广西大学物理科学与工程技术学院筑波大学应用加速器部中国原子能科学研究院北京102413

在筑波大学的12UD串列加速器上开发了一套改进的129Ⅰ加速器质谱(AMS)测量方法,包括在120°磁铁后安装了一副自行设计制作有静电偏转板,有效改善了对127Ⅰ束流和129Ⅰ计数的测量;采用97MoO2分子导航束稳定加速器端电压,加速器的端电压... 详细信息

在筑波大学的12UD串列加速器上开发了一套改进的129Ⅰ加速器质谱(AMS)测量方法,包括在120°磁铁后安装了一副自行设计制作有静电偏转板,有效改善了对127Ⅰ束流和129Ⅰ计数的测量;采用97MoO2分子导航束稳定加速器端电压,加速器的端电压能稳定在几天内不超过0.1%,结合二次剥离,取得了满意的测量效果。用该方法测得AgI试剂样品的本底水平为7.83×10-13。对129Ⅰ/127Ⅰ比值范围为(4.92~0.28)×10-10的一系列样品的测量不确定度在7%以下,准确度较前有所提高。

关键词：加速器质谱 129I测量静电偏转板二次剥离

An integrated preforming-performance model for high-fidelity performance analysis of cured woven composite part with non-orthogonal yarn angles

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Chinese Journal of Aeronautics 2022年第6期35卷 367-378页

作者： Biao LIANG sasa GAO Weizhao ZHANG School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China College of Mechanical&Electrical Engineering Shaanxi University of Science&TechnologyXi’an 710021China Department of Mechanical and Automation Engineering The Chinese University of Hong KongHong KongChina

Preforming process would change yarn angle and yarn orientation,its influence on the material properties and material orientations needs to be considered in the performance ***,most current performance models fail to account for the preforming *** integrated performance model accounting for the impact of preforming has been *** this integrated model,part geometry,yarn angle and orientation after preforming of multiple prepreg layers are predicted by Finite Element Analysis(FEA)using a non-orthogonal constitutive *** were conducted to validate the preforming simulation for a single dome composites structure made by two prepreg layers with different initial fiber *** analysis until failure was then conducted for the single dome structure to validate the integrated performance *** between simulation and experiment shows that not only the failure mode and failure zone,but also the force-displacement curve during compression process are captured correctly by the performance model,demonstrating the effectiveness of the newly proposed model in accounting for the impact of preforming process.

关键词： Mechanical properties Non-orthogonal model Performance analysis Woven composites Yarn angle

Purinergic Modulation of Activity in the Developing Auditory Pathway

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Neuroscience Bulletin 2020年第11期36卷 1285-1298页

作者： sasa Jovanovic Ivan Milenkovic School of Medicine and Health Sciences Carl von Ossietzky University Oldenburg26129 OldenburgGermany

Purinergic P2 receptors,activated by endogenous ATP,are prominently expressed on neuronal and nonneuronal cells during development of the auditory periphery and central auditory *** the mature cochlea,extracellular ATP contributes to ion homeostasis,and has a protective function against noise ***,we focus on the modulation of activity by extracellular ATP during early postnatal development of the lower auditory *** mammals,spontaneous patterned activity is conveyed along afferent auditory pathways before the onset of acoustically evoked signal *** this critical developmental period,inner hair cells fire bursts of action potentials that are believed to provide a developmental code for synaptic maturation and refinement of auditory circuits,thereby establishing a precise tonotopic *** ATP-release triggers such patterned activity by raising the extracellular K+concentration and contributes to firing by increasing the excitability of auditory nerve fibers,spiral ganglion neurons,and specific neuron types within the auditory brainstem,through the activation of diverse P2 *** review recent studies that provide new models on the contribution of purinergic signaling to early development of the afferent auditory ***,we discuss potential future directions of purinergic research in the auditory system.

关键词： Purinergic signaling Auditory system Development Cochlea Spiral ganglion Auditory brainstem

Attenuation and Distortion of Compression Waves Propagating in Very Long Tube

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Journal of Thermal Science 2011年第1期20卷 53-57页

作者： Shinya NAKAMURA Daisuke sasa Toshiyuki AOKI Graduate School of Engineering Sciences Kyushu UniversityKasugaFukuoka816-8580Japan

A lot of phenomena related to propagating various waves are seen when the high-speed train goes through the tunnel,the gas pipeline is broken due to an accident or the air brake of the wagon *** instance,a compression wave generated ahead of a high-speed train entering a tunnel propagates to the tunnel exit and spouts as a micro pressure wave,which causes an exploding *** order to estimate the magnitude correctly,the mechanism of the attenuation and distortion of a compression wave propagating along a very long tunnel must be understood and the experimental information on these phenomena is *** experimental investigation is carried out to clarify the attenuation and distortion of the propagating compression wave in a very long *** results show that the strength of a compression wave decreases with *** attenuation and distortion of compression waves are affected by the initial waveform of the compression wave and by the unsteady boundary layer induced by the propagating *** shape of a compression wave becomes different with the propagating distance;that is,a shock wave appears just head of a wavefront and an overshoot on pressure distribution is observed behind a shock wave due to the transition of the unsteady boundary layer.

关键词： Propagating Compression Wave Very Long Tube Micro-pressure Wave High-Speed Train

Formation mechanism of extension fractures induced by excavation of a gallery in soft sedimentary rock,Horonobe area,Northern Japan

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Geoscience Frontiers 2013年第1期4卷 105-111页

作者： Tetsuya Tokiwa kimikazu Tsusaka Makoto Matsubara Taiki Ishikawa Daisuke Ogawa Horonobe Underground Research Unit Japan Atomic Energy AgencyHokkaido 098-3224Japan Geoscience Research Laboratory Kanagawa 242-0014Japan Mitsubishi Materials Techno Corporation Tokyo 102-8205Japan

This paper focuses on the formation mechanism of fractures induced by excavation of a gallery in soft sedimentary rocks in the Horonobe area of Japan. Detailed fracture mapping of the gallery indicates that the fractures consist of both pre-existing shear fractures and excavation damaged zone （EDZ） fractures. EDZ fractures correspond to weak planes associated with bedding planes or transgranular cracks. The EDZ fractures terminate against pre-existing shear fractures. Therefore, even for excavations in soft sedimentary rocks, formation of the EDZ fractures are controlled by pre-existing fractures and earlier weak planes.

关键词： Fracture Excavation damaged zone (EDZ)Weak plane Soft rock Excavation

A review of CPT based axial pile design in the Netherlands

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Underground Space 2021年第1期6卷 85-99页

作者： Kenneth Gavin Meho sasa Kovacevic David Igoe TU Delft Geo-Engineering SectionFaculty of Civil Engineering and GeosciencesDelft University of TechnologyBuilding 23Stevinweg 1PO-Box 50482628 CN Delft/2600 GA DelftNetherlands University of Zagreb Croatia Trinity College Dublin Ireland

Because of the deltaic nature of the Netherlands,deep soft soil deposits are *** to the population density exploitation of underground space is vital for commercial developments and transport *** are used as primary support elements in deep excavations,cut and cover tunnels,quay walls,flood defences and to provide uplift resistance to the base of tunnels and *** paper examines empirical correlations linking the Cone Penetration Test(CPT)end resistance qc and the resistance of deep foundations in *** is found that correlations between qc and pile end resistance are independent of pile ***,the impact of installation method,residual load,plugging and sand creep should be *** the case of shaft resistance,constant correlation factors between qc and average shaft resistance are possible for non-displacement *** the case of displacement piles,correlations that include the effects of friction fatigue and pile plugging during installation are recommended.

关键词： Piles Sand CPT based methods Design codes

An efficient hyper-elastic model for the preforming simulation of Carbon-Kevlar hybrid woven reinforcement

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Chinese Journal of Aeronautics 2022年第12期35卷 321-335页

作者： sasa GAO Zhengtao QU Yunjie ZHANG Zizhao ZHAO Biao LIANG College of Mechanical&Electrical Engineering Shaanxi University of Science&TechnologyXi’an 710021China State Key Laboratory of Applied Optics Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China

An efficient hyper-elastic model that can reflect the primary mechanical behaviors of Carbon-Kevlar hybrid woven reinforcement was developed and implemented with VUMAT constitutive code for preforming *** model parameters were accurately determined through the uniaxial and bias-extension *** calibrate the simulation code,preforming experiments of hybrid woven reinforcement over the hemisphere mold and tetrahedron mold were respectively conducted to validate the proposed hyper-elastic *** comparison between the simulations and experiments shows that the model can not only accurately capture shear angle distribution and geometry shape after deformation,but also accurately predict the force–displacement curve and potential fiber tensile failure during the preforming *** result indicates that the proposed model can be used to predict the preforming behavior of Carbon-Kevlar hybrid woven reinforcement,and simulate its manufacturing process of complicated geometry.

关键词： Constitutive law Finite element analysis Hybrid woven reinforcement Hyper-elastic Preforming

Simulating hydraulic fracturing processes in laboratory-scale geological media using three-dimensional TOUGH-RBSN

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第6期10卷 1102-1111页

作者： Daisuke Asahina Pengzhi Pan kimikazu Tsusaka Mikio Takeda John E.Bolander Geological Survey of Japan IbarakiJapan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China INPEX Corporation TokyoJapan University of California DavisUSA

In this context, recent developments in the coupled three-dimensional(3 D) hydro-mechanical(HM)simulation tool TOUGH-RBSN are presented. This tool is used to model hydraulic fracture in geological media, as observed in laboratory-scale tests. The TOUGH-RBSN simulator is based on the effective linking of two numerical methods: TOUGH2, a finite volume method for simulating mass transport within a permeable medium; and a lattice model based on the rigid-body-spring network(RBSN) concept. The method relies on a Voronoi-based discretization technique that can represent fracture development within a permeable rock matrix. The simulator provides two-way coupling of HM processes, including fluid pressure-induced fracture and fracture-assisted flow. We first present the basic capabilities of the modeling approach using two example applications, i.e. permeability evolution under compression deformation, and analyses of a static fracturing simulation. Thereafter, the model is used to simulate laboratory tests of hydraulic fracturing in granite. In most respects, the simulation results meet expectations with respect to permeability evolution and fracturing patterns. It can be seen that the evolution of injection pressure associated with the simulated fracture developments is strongly affected by fluid viscosity.

关键词： Hydraulic fracture Crack opening TOUGH Rigid-body-spring network(RBSN) Permeability Injection pressure Fluid viscosity Hydro-mechanical(HM) processes