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Journal of Earth Science 2020年第5期31卷 884-895页

作者： Muhammad Ayoub Khan Muhammad Ishaq Kakar thomas ulrich Liaqat Ali Andrew CKerr Khalid Mahmood Rehanul Haq Siddiqui Center of Excellence in Mineralogy University of BalochistanQuettaPakistan Department of Geoscience Aarhus UniversityHoegh-Guldbergs Gade 2QK-8000 Aarhus CDenmark National Center of Excellence in Geology University of PeshawarPeshawarPakistan School of Earth and Ocean Sciences Cardijf UniversityCardiffWales CF103 YEUK Department of Earth Sciences、University of Sargodha SargodhaPakistan Balochistan University of Information Technology Engineering and Management SciencesQuettaPakistan

The Zhob ophiolite comprises the Naweoba, Omzha and Ali Khanzai blocks, which are surrounded by the sediments of the Alozai Group and Loralai Formation. The Ali Khanzai Block contains metamorphic, ultramafic, gabbroic, volcanic and volcaniclastic rocks with associated chert. The Zhob manganese deposits found in the Ali Khanzai Block, occur in banded, lenticular and massive forms within red to brown coloured metachert. Braunite and pyrolusite are the main constituent manganese-bearing minerals with minor hausmannite, hematite and barite while quartz is the major gangue mineral with some carbonate minerals. Geochemical evidence from the major oxides indicates that the manganese mineralization and associated metachert at Zhob were formed by hydrothermal activity with little contribution from contemporaneous volcanic materials and this is confirmed by high Fe/Mn and low Co/Zn ratios and trace element patterns. These deposits formed along with seafloor spreading centres and were later obducted as part of Ali Khanzai Block of Zhob ophiolite.

关键词： Zhob ophiolite manganese ore hydrothermal genesis

Dynamic convergent shock compression initiated by return current in high-intensity laser-solid interactions

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Matter and Radiation at Extremes 2024年第4期9卷 40-53页

作者： Long Yang Martin Rehwald thomas Kluge Alejandro LasoGarcia Toma Toncian Karl Zeil ulrich Schramm thomas E.Cowan Lingen Huang Helmholtz-Zentrum Dresden-Rossendorf 01328 DresdenGermany Technische Universitat Dresden 01062 DresdenGermany

We investigate the dynamics of convergent shock compression in solid cylindrical targets irradiated by an ultrafast relativistic laser *** particle-in-cell simulations and coupled hydrodynamic simulations reveal that the compression process is initiated by both magnetic pressure and surface ablation associated with a strong transient surface return current with density of the order of 10^(17) A/m^(2) and lifetime of 100 *** results show that the dominant compression mechanism is governed by the plasma β,i.e.,the ratio of thermal pressure to magnetic *** targets with small radius and low atomic number Z,the magnetic pressure is the dominant shock compression *** to a scaling law,as the target radius and Z increase,the surface ablation pressure becomes the main mechanism generating convergent ***,an indirect experimental indication of shocked hydrogen compression is provided by optical shadowgraphy measurements of the evolution of the plasma expansion *** results presented here provide a novel basis for the generation of extremely high pressures exceeding Gbar(100 TPa)to enable the investigation of high-pressure physics using femtosecond J-level laser pulses,offering an alternative to nanosecond kJ-laser pulse-driven and pulsed power Z-pinch compression methods.

关键词： shock convergent return

单个流体包裹体LA-ICPMS定量分析技术及其应用(英文)

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地学前缘 2003年第2期10卷 379-393页

作者： thomas ulrich Geology Department Australian National University 澳大利亚

对于不同类型的地球化学勘查样品 ,运用恰当的分析方法处理 ,是成功地发现矿床的关键。激光熔融电感耦合等离子质谱分析 ,即LA ICPMS ,是功能最强的多元素分析技术之一。该方法获得数据快捷 ,样品制备简单 ,其高灵敏度为很多主元素和微... 详细信息

对于不同类型的地球化学勘查样品 ,运用恰当的分析方法处理 ,是成功地发现矿床的关键。激光熔融电感耦合等离子质谱分析 ,即LA ICPMS ,是功能最强的多元素分析技术之一。该方法获得数据快捷 ,样品制备简单 ,其高灵敏度为很多主元素和微量元素 (包括铂族元素、稀土元素、高场强元素和多种成矿示踪元素 )提供了低检测限 ,正在并将要持续为地球化学应用提供新的信息。仪器由ICPMS(四极 ,多接受或磁扇域 )附加激光器 (紫外或红外波长 )而构成。应用于地球科学研究的标准仪器的激光器为具有 2 6 6nm四倍频率的Nd :YAG激光器 ,或者是具有 193nm波长的ArF激态原子激光器。激光器熔融样品 ,并通过运载气体将熔融的样品物质传送到IP ,而不是将样品溶解后 ,通过雾化器和雾化室将样品传输给ICP。这就使我们能够进行微区分析 ,如矿物环带 ,或者矿物中的微小矿物、融体和流体包裹体等。运用外标校对元素比值 ,并结合内标使用 ,可以获得定量测试结果。对于固体熔融物的分析精度一般为 2 %～ 5 %RSD(相对标准误差 ) ,对于流体包裹体则为 10 %～ 30 %RSD。LA ICPMS的一些复杂系统可能引起成分分馏和质量干扰。对于分馏效应 ,可以通过运用产生小粒子的短波长激光器和运用He作为运载气体来减小 ;对于质量干扰 ,则可以通过?

关键词：流体包裹体地球化学勘查样品激光熔融电感耦合等离子质谱分析微量元素铂族元素稀土元素地球科学研究雾化器雾化室

A simulation study on spatial and time resolution for a cost-effective positron emission particle tracking system

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Particuology 2024年第5期88卷 312-322页

作者： Josephine Oppotsch Matthias Steinke Miriam Fritsch Fritz-Herbert Heinsius thomas Held Nikoline Hilse Viktor Scherer ulrich Wiedner Ruhr-Universität Bochum Institut für Experimentalphysik I44801 BochumGermany Ruhr-Universität Bochum Lehrstuhl für Energieanlagen und Energieprozesstechnik44801 BochumGermany

This work is the second part of a simulation study investigating the processing of densely packed and moving granular assemblies by positron emission particle tracking (PEPT).Since medical positron emission tomography (PET) scanners commonly used for PEPT are very expensive,a PET-like detector system based on cost-effective organic plastic scintillator bars is being developed and tested for its *** this context,the spatial resolution of a resting positron source,a source moving on a freely designed model path,and a particle motion given by a discrete element method (DEM) simulation is studied using Monte Carlo simulations and the software toolkit *** not only extended the simulation and reconstruction to a moving source but also significantly improved the spatial resolution compared to previous work by adding oversampling and iteration to the reconstruction ***,in the case of a source following a trajectory developed from DEM simulations,a very good resolution of about 1 mm in all three directions and an average 3D deviation between simulated and reconstructed events of 2.3 mm could be ***,the resolution for realistic particle motion within the generic grate system (which is the test rig for further experimental studies) is well below the smallest particle *** simulation of the dependence of the reconstruction accuracy on tracer particle location revealed a nearly constant efficiency within the entire detector system,which demonstrates that boundary effects can be neglected.

关键词： Positron emission particle tracking Monte Carlo method Time-of-flight Plastic scintillators Silicon photomultipliers(SiPMs)

A simulation study for a cost-effective PET-like detector system intended to track particles in granular assemblies

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Particuology 2024年第1期84卷 117-125页

作者： Josephine Oppotsch Antonios Athanassiadis Miriam Fritsch Fritz-Herbert Heinsius thomas Held Nikoline Hilse Viktor Scherer Matthias Steinke ulrich Wiedner Ruhr-Universität Bochum Institut für Experimentalphysik I44801 BochumGermany Ruhr-Universität Bochum Lehrstuhl für Energieanlagen und Energieprozesstechnik44801 BochumGermany

Since many industrial applications rely on the processing of densely packed and moving granular ma-terial,obtaining bulk internal information on the particle movement inside the reactors is of great *** information can be delivered by Positron Emission Particle Tracking(PEPT).By marking pellets with a positron-emitting radioisotope,the position of these tracer particles can be determined via the time-of-flight differences of the emitted gamma-ray *** current paper proposes a PET-like detector system based on cost-effective organic plastic scintillators instead of the more common but expensive inorganic *** system is currently under construction and was tested for its resolution and efficiency in this simulation *** Monte Carlo simulations and the software toolkit Geant4,three different geometries(an empty glass box,a generic grate system,and a cubic box of 1 m3 completely filled with pellets)were investigated,leading to a spatial resolution in the millimeter range and an efficiency,defined as the ratio of reconstructed decay locations to simulated decays,of 2.7%,1.4%,and 0.3%.

关键词： Positron emission particle tracking Geant4 Monte Carlo method Time-of-flight Plastic scintillators Silicon photomultipliers(SiPMs)

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增加自由空间

现代制造 2005年第7期 52-53页

作者： thomas ulrich

在钻镗床各个坐标方向的较大自由空间为用户提供了很高的使用性能。通过两次装夹即可完成大型复杂工件任意轮廓形状的全部加工工序,并可以减少大量的辅助工时。

关键词：镗床数控加工加工精度加工工序

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镗铣床移动式工作台实现经济性加工

现代制造 2013年第21期 56-57页

作者： thomas ulrich

大型减速箱的加工向镗铣床提出了高精度的要求，在部件长度为4－5m的情况下，加工误差须保持在0.01mm以内。为了降低热影响，设备在所有轴上配备了流体静力导向技术并采用双壁式立柱。

关键词：加工误差镗铣床经济性工作台移动式导向技术高精度减速箱

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完成大型零件钻铣加工的精加工机床

现代制造 2009年第27期 70-70,72页

作者： thomas ulrich

加工又重又高的大型零件时,不仅对工艺技术提出了很高的要求,而且对加工机床本身的加工能力也提出了很大的挑战。作为加工这种大型零件的一种解决方案,钻铣加工中心是一个很好的选择。

关键词：精加工机床大型零件铣加工加工能力加工中心钻铣

Distortions in focusing laser pulses due to spatio-temporal couplings:an analytic description

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High Power Laser Science and Engineering 2024年第3期12卷 20-40页

作者： Klaus Steiniger Fabia Dietrich Daniel Albach Michael Bussmann Arie Irman Markus Loeser Richard Pausch thomas Püschel Roland Sauerbrey Susanne Schöbel ulrich Schramm Mathias Siebold Karl Zeil Alexander Debus Helmholtz-Zentrum Dresden-Rossendorf DresdenGermany CASUS-Center for Advanced Systems Understanding GörlitzGermany Technische Universität Dresden DresdenGermany

In ultra-short laser pulses,small changes in dispersion properties before the final focusing mirror can lead to severe pulse distortions around the focus and therefore to very different pulse properties at the point of laser±matter interaction,yielding unexpected interaction *** mapping between far-and near-field laser properties intricately depends on the spatial and angular dispersion properties as well as the focal *** a focused Gaussian laser pulse under the influence of angular,spatial and group-delay dispersion,we derive analytical expressions for its pulse-front tilt,duration and width from a fully analytic expression for its electric field in the time±space domain obtained with scalar diffraction *** expression is not only valid in and near the focus but also along the entire propagation distance from the focusing mirror to the *** relating angular,spatial and group-delay dispersion before focusing at an off-axis parabola,where they are well measurable,to the respective values in the pulse’s focus are obtained by a ray tracing ***,these formulas are used to show in example setups that the pulse-front tilts of lasers with small initial dispersion can become several tens of degrees larger in the vicinity of the focus while being small directly in the *** formulas derived here provide the analytical foundation for observations previously made in numerical *** numerically simulating Gaussian pulse propagation and measuring properties of the pulse at distances several Rayleigh lengths off the focus,we verify the analytic expressions.

关键词： group-delay dispersion pulse-front tilt spatio-temporal couplings third-order dispersion ultra-short laser pulses

Insights into carbon dioxide sequestration into coal seams through coupled gas flow-adsorption-deformation modelling

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 26-40页

作者： Hywel thomas Min Chen Geoenvironmental Research Centre Cardiff School of EngineeringCardiff UniversityQueen’s BuildingsThe ParadeNewport RoadCardiffCF243AAUK Key Laboratory of Marine Geology Tongji UniversityShanghai200092China

Injecting carbon dioxide(CO_(2))into coal seams may unlock substantial carbon sequestration *** the coal acts like a carbon filter,it can preferentially absorb significant amounts of CO_(2).To explore this further,desorption of the adsorbed gas due to pressure drop is investigated in this paper,to achieve an improved understanding of the long-term fate of injected CO_(2) during post-injection *** paper presents a dual porosity model coupling gas flow,adsorption and geomechanics for studying coupled processes and effectiveness of CO_(2) sequestration in coals.A new adsorption?desorption model derived based on thermodynamics is incorporated,particularly,the desorption hysteresis is *** reliability of the proposed adsorption-desorption isotherm is examined via validation *** is indicated that occurrence of desorption hysteresis is attributed to the adsorption-induced pore *** injection ceases,the injected gas continues to propagate further from the injection well,while the pressure in the vicinity of the injection well experiences a significant *** the adsorbed gas near the well also decreases,this decrease is less compared to that in pressure because of desorption *** unceasing spread of CO_(2) and drops of pressure and adsorbed gas depend on the degree of desorption hysteresis and heterogeneity of coals,which should be considered when designing CO_(2) sequestration into coal seams.

关键词： CO_(2)geological storage Coal seam Adsorption Desorption hysteresis