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Petroleum 2017年第1期3卷 96-108页

作者： Christina Hemme Wolfgang van Berk tu clausthal Institute of Disposal ResearchDepartment of HydrogeologyLeibnizstrasse 1038642 Clausthal-ZellerfeldGermany

Carbon capture and storage in deep geological formations is a method to reduce greenhouse gas *** CO_(2) is injected into a reservoir and dissolves in the *** the impact of pressure and temperature(P-T)the aqueous species of the CO_(2)-acidified brine diffuse through the cap rock where they trigger CO_(2)-watererock *** geochemical reactions result in mineral dissolution and precipitation along the CO_(2) migration path and are responsible for a change in porosity and therefore for the sealing capacity of the cap *** study focuses on the diffusive mass transport of CO_(2) along a gradient of decreasing PeT *** process is retraced with a one-dimensional hydrogeochemical reactive mass transport *** semigeneric hydrogeochemical model is based on chemical equilibrium *** on a broad variety of scenarios,including different initial mineralogical,chemical and physical parameters,the hydrogeochemical parameters that are most sensitive for safe long-term CO_(2) storage are *** results demonstrate that PeT conditions have the strongest effect on the change in porosity and the effect of both is stronger at high PeT conditions because the solubility of the mineral phases involved depends on PeT ***,modeling results indicate that the change in porosity depends strongly on the initial mineralogical composition of the reservoir and cap rock as well as on the brine ***,a wide range of conditions for safe CO_(2) storage is identified.

关键词： rock reservoir geochemical

Origion of Band-like and Atom-like Features of the Valence Band Auger Emission from Thansition Metals

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Journal of Materials Science & Technology 1999年第4期15卷 375-376页

作者： Jianmin YUAN(Department of Applied Physics, National University of Defense Technology, Changsha 410073, China)L.Intsche and J.Nome(Institut fr Theoretische Physik B, tu clausthal D-38678 clausthal-Zellerfeld, Germany)To whom correspondence should be addre Department of Applied Physics National University of Defense Technology Changsha 410073 China Institut für Theoretische Physik B TU Clausthal D-38678 Clausthal-Zellerfeld Germany

The occurrence of both band-like and atom-like Auger spectra involving valence band electron of d-transition metals is discussed based on the two-step model of the Auger electron emission, *** initial core-hole is first generated and the Auger transition occurs between the core-hole andthe valence states, The occupied vaIence states relax to screen the core-hole which results in a redistribution of the valence electrons, The electronic states concerned by the Auger transitionare calculated by the FLAPW method. There is a clear relation between band-like and atom-like features of the spectra and the different responses of these metals to the existence of a core-hole.

关键词： Atom Origion of Band-like and Atom-like Features of the Valence Band Auger Emission from Thansition Metals Rev

Modeling of a Cubic Antiferromagnetic Cuprate Super-Cage

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World Journal of Condensed Matter Physics 2015年第3期5卷 160-178页

作者： Hans Hermann Otto Materialwissenschaftliche Kristallographie TU Clausthal Clausthal-Zellerfeld Germany

Convex polyhedral cuprate clusters are being formed through lateral frustration when the a and c lattice parameters of the tetragonal ACuO2 infinite layer structure will become identical by substitution of a large cation (A = Ba2+). However, the corner-shared CuO2 plaquettes of the infinite network suffer a topotactic rearrangement forming edge-connected units, for instance Cu18O24 cages (polyhedron notation [4641238]) with 2 compound (space group P4/ nmm) will be discussed. The possibility to construct a cuprate super-cage with m3m symmetry (polyhedron notation [4641242438]) is being reported. This super-cage still consists of edge-connected CuO2 plaquettes when fully decorated with copper ions, but with different curvatures, arranged in circles of 9.39 ? of diameter with 139.2° Cu-O-Cu antiferromagnetic super-exchange interaction. On the one hand, the realization of such a quite stable cuprate super-cage as a candidate for high-Tc superconductivity depends on whether a template of suitable size such as the cation or C(CH3)4 enables its formation, and on the other hand the cage can further be stabilized by highly charged cations located along the [111] direction. Synthesis options will be proposed based on suggested cage formation pathways. An X-ray powder pattern was calculated for a less dense cluster structure of Im3m space group with a lattice parameter of a = 14.938 ? and two formula units of Cu46O51 to facilitate future identification. Characteristic X-ray scattering features as identification tool were obtained when the electron distribution of the hollow polyhedron was approximated with electron density in a spherical shell.

关键词： Super-Cage Convex Polyhedra Cuprate BaCuO2 T-CuO Superconductivity Bond Strength Frustration X-Ray Pattern

A Study on Configuration and Integration of Sub-Systems to System-of-Systems with Rule Verification

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Engineering（科研） 2015年第10期7卷 625-643页

作者： Tim Warnecke Department of Computer Science TU Clausthal Clausthal-Zellerfeld Germany

Increasing complexity of today’s software systems is one of the major challenges software engineers have to face. This is aggravated by the fact that formerly isolated systems have to be interconnected to more complex systems, called System-of-Systems (SoS). Those systems are in charge to provide more functionality to the user than all of their independent sub-systems could do. Reducing the complexity of such systems is one goal of the software engineering paradigm called component-based software engineering (CBSE). CBSE enables the developers to treat individual sub-systems as components which interact via interfaces with a simulated environment. Thus those components can be developed and implemented independently from other components. After the implementation a system integrator is able to interconnect the components to a SoS. Despite this much-used approach it is possible to show that constraints, which are valid in an isolated sub-system, are broken after this system is integrated into a SoS. To emphasize this issue we developed a technique based on interconnected timed automata for modelling sub-systems and System-of-Systems in the model checking tool UPPAAL. The presented modelling technique allows it to verify the correctness of single sub-systems as well as the resulting SoS. Additionally we developed a tool which abstracts the complicated timed automata to an easy to read component based language with the goal to help system integrators building and verifying complex SoS.

关键词： System-of-Systems CBSE Verification Model Checking UPPAAL

Can Distributed Ledgers Help to Overcome the Need of Labeled Data for Agricultural Machine Learning Tasks?

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Plant Phenomics 2023年第3期5卷 391-394页

作者： Stefan Paulus Benjamin Leiding Institute of Sugar Beet Research Holtenser Landstr.7737079 GöttingenGermany Institute for Software and Systems Engineering TU ClausthalWallstr.638640 GoslarGermany

Introduction Plant phenotyping describes the result of the interaction of genotype with the environment[1].This is performed with high throughput in greenhouses by automated screening systems using different types of imaging and non-imaging sensors[2].The high-throughput imaging routines result in large amounts of data,which require sophisticated processing *** and reusing phenotype-related data are not common,because its acquisition and processing are resource costly and technically intensive[3].

关键词： routine processing throughput

Small-Scale Mineralogical Heterogeneity from Variations in Phase Assemblages in the Transition Zone and D" Layer Predicted by Convection Modelling

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Journal of Earth Science 2011年第2期22卷 160-168页

作者： Arie P van den Berg David A Yuen Michael H G Jacobs Maarten V de Hoop Earth Sciences Department Utrecht University Department of Geology and Geophysics and Minnesota Supercomputing Institute University of MinnesotaMinneapolisMN 55415USA Institut für Metallurgie TU ClausthalClausthal-ZellerfeldGermany Department of Mathematics and Center of Applied and Computational Mathematics Purdue UniversityWest LafayetteINUSA

Small-scale heterogeneity in the deep mantle is concentrated in the upper-mantle transition zone （TZ）, in the depth range 410-660 km and also at the bottom 250 km D＂ region. This encourages a more detailed investigation of the potential for seismic reflectivity imaging by modelling heterogeneous structures in mantle convection models including phase transitions of the TZ and D＂ regions. We applied finite elements with variable spacing near the boundary layers in 2-D cylindrical geometry that allow for sufficient spatial resolution. We investigated several models including an extended Boussinesq （EBA） model, focused on the D＂ region, and a compressible （ALA） model for the TZ region. The results for the D＂ region show typical lens-shaped structures of post-perovskite （PPV） embedded in the perovskite （PV） background mantle, where the thickness of the lenses, at 200-400 km, strongly depends on the Clapeyron slope of the PV-PPV transition. A second phase transition （double crossing） occurs in case the core temperature is higher than the intercept temperature Ti. Our phase-dependent rheology results in contrasting effective viscosity between PV and PPV. Our model results reveal a distinctly clear mechanical weakening of the PPV lenses with about an order of magnitude lower viscosity. The shear wave-speed distributions computed from our convection results are strongly correlated with the heterogeneous distribution of the mineral phase. Gradients in the seismic wave-speed that are the target of seismological reflectivity imaging are clearly revealed. The wave-speed results show a clear resolution of the top and bottom interfaces of the PPV lenses. Our ALA model for the TZ is based on a thermodynamical model for the magnesium end- member of an olivine-pyroxene mantle. The model predicts a much more complex distribution of mineral phases, compared to our D＂ results, in agreement with the greater number of mineral phases involved in the olivine-pyroxene phase diagram for the P

关键词： mantle convection phase transition post-perovskite mineralogical heterogeneity.

Electrodeposition of Al from a 1-butylpyrrolidine-AlCl3 ionic liquid

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Progress in Natural Science:Materials International 2015年第6期25卷 603-611页

作者： Giridhar Pulletikurthi Bj?rn B?decker Andriy Borodin Bernd Weidenfeller Frank Endres Institute of Electrochemistry Clausthal University of Technology

The addition of 1-butylpyrrolidine to AlCl3results in the formation of an electrolyte that is suited to Al *** feasibility of electrodepositing Al from the synthesized electrolyte was *** compositions of AlCl3and 1-butylpyrrolidine were prepared for this *** mixtures show a different phase behavior at various compositions of AlCl3and ***,Raman and NMR spectroscopy were employed to characterize the synthesized *** the prepared compositions,1:1.2 mol ratio of 1-butylpyrrolidine:AlCl3and the upper phase of 1:1.3 mol ratio of 1-butylpyrrolidine:AlCl3were found to be suitable for Al electrodeposition at room temperature（RT）.Uniform and thick（ mm thick） layers of Al were obtained on copper at *** deposition occured from the cationic species of AlCl3xLty（where x r 2,y ? 1–2,and L ? 1-butylpyrrolidine） in this *** behavior is contrary to the well investigated classic AlCl3based ionic liquids,where the deposition of Al occurs mainly from anionic Al2 Cl 7ions.

关键词： Aluminium Al cations 1-butylpyrrolidine Ionic liquid Electrodeposition

Graphite Nucleation in Cast Iron Melts Based on Solidification Experiments and Microstructure Simulation

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Journal of Materials Science & Technology 2008年第3期24卷 321-324页

作者： Andreia Sommerfeld Bernd Bttger Babette Tonn Institute of Metallurgy Clausthal University of TechnologyClausthal-Zellerfeld ACCESS e.V. Intzestr.552072 Aachen

Microstructure strongly influences the mechanical properties of cast iron. By inoculating the melt with proper inoculants, foreign substrates are brought into the melt and eventually the graphite can crystallize on them. The elements and substrates that really play a role for nucleation are yet unknown. Until now there is very little knowledge about the fundamentals of nucleation, such as composition and morphology of nuclei. In this work we utilized EN-GJL-200 as a base material and examined several produced specimens. The specimens were cast with and without inoculants and quenched at different solidification states. Specimens were also examined with a high and low oxygen concentration, but the results showed that different oxygen contents have no influence on the nucleation in cast iron melts. Our research was focused on the microscopic examination and phase-field simulations. For studying the samples we applied different analytical methods, where SEM-EDS, -WDS were proved to be most effective. The simulations were conducted by using the software MICRESS, which is based on a multiphase-field model and has been coupled directly to the TCFE3 thermodynamic database from TCAB. On the basis of the experimental investigations a nucleation mechanism is proposed, which claims MnS precipitates as the preferred site for graphite nucleation. This theory is supported by the results of the phase-field simulations.

关键词： Graphite nucleation Cast iron melts Solidification Microstructure simulation

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

Mechanical characterization of cp-Ti produced by investment casting

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Transactions of Nonferrous Metals Society of China 2011年第8期21卷 1735-1740页

作者： Khaled M.IBRAHIM Mansour MHAEDE Lothar WAGNER Central Metallurgical R&D Institute(CMRDI) Institue of Materials Science and Engineering TU-Clausthal

The influence of hot swaging（SW） and annealing treatment on microstructure and mechanical properties of commercially pure titanium produced by investment casting was *** as-cast samples showed a typical microstructure consisting of a variety of α-morphologies,while the hot swaged samples exhibited a kinked lamellar *** at 500 °C did not significantly change this microstructure while annealing at 700 and 870 °C led to recrystallization and formation of equiaxed *** cast bars exhibited a typical hard α-layer in near-surface regions with a maximum depth and maximum hardness of 720 μm and HV0.5 660,*** to SW,the tensile strength of the as-cast material drastically increased from 605 MPa to 895 *** at 500 °C decreased the tensile strength slightly from 895 to 865 MPa while annealing at 700 °C led to a further pronounced drop in tensile strength from 865 to 710 *** additional decrease in tensile strength was noticed with increasing the annealing temperature from 700 to 870 °*** true fracture strain of the as-cast and hot swaged samples was in the range of 0.05 to 0.12,while the annealed samples showed values in the range of 0.25 to *** addition,the as-cast and hot swaged samples revealed a brittle cleavage fracture ***,the annealed samples showed a transgranular ductile fracture with formation of dimples.

关键词： pure titanium investment casting swaging thermo-mechanical processing mechanical properties