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Enantioconvergent photoredox radical-radical coupling catalyzed by a chiral-at-rhodium complex

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Science China Chemistry 2019年第11期62卷 1512-1518页

作者： Zijun Zhou Xin Nie Klaus Harms Radostan Riedel Lilu Zhang Eric Meggers Fachbereich Chemie Philipps-Universit?t Marburg

Racemicα-chloro imidazol-2-yl-ketones undergo an enantioconvergent photoactivated C–C bond formation with N-aryl glycines catalyzed by a single bis-cyclometalated chiral-at-rhodium catalyst in yields of up to 80%and up to 98%enantiomeric excess(ee).Control experiments support a mechanism which is initiated by a single electron transfer from N-aryl glycinate to the photochemically excited rhodium-boundα-chloro imidazol-2-yl-ketone,followed by chloride fragmentation of theα-chloroketone,decarboxylation of the glycinate,and a subsequent highly stereocontrolled radical-radical *** work showcases the ability of the chiral rhodium catalyst to serve a dual function as chiral Lewis acid and at the same time as the photoredox active species upon substrate binding.

关键词： photoredox catalysis asymmetric catalysis visible light enantioconvergent radical recombination chiral-at-metal rhodium

Measurement of in-plane deformations of microsystems by digital holography and speckle interferometry(Invited Paper)

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Chinese Optics Letters 2009年第12期7卷 1109-1112页

作者： G. Pedrini J. Gaspar O. Paul W. Osten Institut fr technische Optik Universitt Stuttgart Department of Microsystems Engineering-IMtEK Universitt Freiburg

the reliability of microsystems is an important issue and for their quality inspection, it is necessary to know the displacements or deformations due to the applied mechanical, thermal, or electrostatic loads. We show how interferometrical techniques like digital holography and speckle interferometry can be used for the measurement of in plane deformations of microsystems with nanometric accuracy and we give a description of the measurement uncertainties.

关键词： Invited Paper Measurement of in-plane deformations of microsystems by digital holography and speckle interferometry

Numerical investigation of the effectiveness of radon control measures in cave mines

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International Journal of Mining Science and technology 2019年第3期29卷 469-475页

作者： Kayode Ajayi Khosro Shahbazi Purushotham tukkaraja Kurt Katzenstein Department of Mechanical Engineering SDSM & TRapid City SD 57701USA Department of Mining Engineering and Management SDSM & TSD 57701USA Department of Geology and Geological Engineering SDSM & TSD 57701USA

Ventilation is one of the radon control measures in an underground working ***,the dynamics related to the cave mining methods particularly in block/panel cave mines,complicate the design of effective ventilation system,and *** such as hang ups(in the drawbells),leakage from old workings,and changes in cave porosity lead to differing response of an existing ventilation ***,it is difficult to investigate these conditions at the mine or with a laboratory scale ***,this study develops a discrete model to investigate the impact of different radon control measures in cave mines using computational fluid dynamics *** considered two ventilation conditions for a fully developed cave:with and without the undercut *** each of the two conditions,we studied four parameters:airflow distribution through the production drifts,radon distribution through the production drifts,the effect of increasing airflow on radon concentration,and the effect of a cave top negative pressure on radon *** results show that:the undercut ventilation significantly increases the radon concentration in the production drift;the growth of radon concentration through the production drift is nonlinear(oscillating pattern);maintaining a negative pressure on top of the cave is more effective at mitigating radon exposure,when the undercut ventilation is active;and increase in air volume flow rate decreases radon concentration in most regions,however,there might be regions with significant radon accumulation due to pressure variation across the *** findings provide vital information for designing an effective ventilation system and for proactive implementation of radon control measures in cave mines.

关键词： Radon gas Underground mining Panel cave mines Broken rocks Computational fluid dynamics(CFD) Porous media Cave mining method

On strong-scaling and open-source tools for analyzing atom probe tomography data

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npj Computational Materials 2021年第1期7卷 148-157页

作者： Markus Kühbach Priyanshu Bajaj Huan Zhao Murat HÇelik Eric AJägle Baptiste Gault Max-Planck-Institut für Eisenforschung GmbH(MPIE) DüsseldorfGermany m4p material solutions GmbH MagdeburgGermany Institute for Advanced Simulation(IAS) Jülich Supercomputing Centre(JSC)JülichGermany Universität der Bundeswehr München NeubibergGermany Department of Materials Imperial College LondonRoyal School of MinesLondonUK

the development of strong-scaling computational tools for high-throughput methods with an open-source code and transparent metadata standards has successfully transformed many computational materials science *** such tools are mature already in the condensed-matter physics community,the situation is still very different for many *** probe tomography(APt)is one *** microscopy and microanalysis technique has matured into a versatile nano-analytical characterization tool with applications that range from materials science to geology and possibly ***,data science tools are required for extracting chemo-structural spatial correlations from the reconstructed point *** APt and other high-end analysis techniques,post-processing is mostly executed with proprietary software tools,which are opaque in their execution and have often limited *** development by members of the scientific community has improved the situation but compared to the sophistication in the field of computational materials science several gaps *** is particularly the case for open-source tools that support scientific computing hardware,tools which enable high-throughput workflows,and open welldocumented metadata standards to align experimental research better with the fair data stewardship *** this end,we introduce paraprobe,an open-source tool for scientific computing and high-throughput studying of point cloud data,here exemplified with *** show how to quantify uncertainties while applying several computational geometry,spatial statistics,and clustering tasks for post-processing APt datasets as large as two billion *** tools work well in concert with Python and HDF5 to enable several orders of magnitude performance gain,automation,and reproducibility.

关键词： hardware Python execution

Geoelectrical survey over perched aquifers in the northern part of Upper Sakarya River Basin,türkiye

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Journal of Groundwater Science and Engineering 2022年第4期10卷 335-352页

作者： Can Ertekin Emin U Ulugergerli Aegean Regional Directorate of Mineral Research and Exploration İzmirTürkiye Çanakkale Onsekiz Mart University Department of Geological EngineeringTerzioğlu CampusÇanakkaleTürkiye Çanakkale Onsekiz Mart University Engineering FacultyDepartment of Geophysical EngineeringTerzioğlu CampusÇanakkaleTürkiye

In this study,a groundwater exploration survey was conducted using the DC Resistivity(DCR)method in a hydrogeological setting containing a perched *** data were gathered and an electrical tomography section was recovered using conventional four-electrode instruments with a Schlumberger array and a two-dimensional(2D)inversion *** proposed scheme was tested over a synthetic threedimensional(3D)subsurface model before deploying it in a field *** proposed method indicated that gathering data with simple four-electrode instruments at stations along a line and 2D inversion of datasets at multiple stations can recover depth intervals of the studied aquifer in the hydrogeological setting even if it has a 3D *** this study,2D inversion of parallel profiles formed a pseudo-3D volume of the subsurface resistivity structures and mapped out multiple resistive(>25 ohm·m)bodies at shallow(between 50-100 m)and deep sections(>150 m).In general,the proposed method is convenient to encounter geological units that have limited vertical and spatial extensions in any direction and presents resistivity contrast from groundwater-bearing geologic materials.

关键词： Groundwater Perched Aquifer DC Resistivity Inversion Sakarya River türkiye

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Hadron molecules

Chinese Physics C 2010年第9期34卷 1185-1190页

作者： thomas Gutsche tanja Branz Amand Faessler Ian Woo Lee Valery E.Lyubovitskij Institut für theoretische Physik Universitt TübingenKepler Center for Astro and Particle Physics

We discuss a possible interpretation of the open charm mesons D＊s0 （2317）,D s1 （2460） and the hidden charm mesons X（3872）,Y（3940） and Y（4140） as hadron *** a phenomenological Lagrangian approach we review the strong and radiative decays of the D＊ s0 （2317） and D s1 （2460） *** X（3872） is assumed to consist dominantly of molecular hadronic components with an additional small admixture of a charmonium *** the radiative （γJ/ψ and γψ（2s）） and strong （J/ψ2π and J/ψ3π） decay modes we show that the present experimental observation is consistent with the molecular structure assumption of the X（3872）.Finally,we give evidence for molecular interpretations of the Y（3940） and Y（4140） related to the observed strong decay modes J/ψ＋ω or J/ψ＋φ,respectively.

关键词： charm mesons hadronic molecule strong and radiative decay

Grade zero part of forced graded algebras

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Science China Mathematics 2018年第2期61卷 269-286页

作者： Hankyung Ko Mathematisches Institut Universitt Bonn

this paper concerns a certain subcategory of the category of representations for a semisimple algebraic group G in characteristic p, which arises from the semisimple modules for the corresponding quantum group at a p-th root of unity. the subcategory, thus, records the cohomological difference between quantum groups and algebraic groups. We define translation functors in this category and use them to obtain information on the irreducible characters for G when the Lusztig character formula does not hold.

关键词： algebraic groups quantum groups cohomology characters

Relationship between magnetic parameters and heavy element contents of arable soil around a steel company,Nanjing

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Science China Earth Sciences 2010年第3期53卷 411-418页

作者： BLAHA U ROESLER W APPEL E Institute for Geosciences University of Tübingen

Magnetic parameters and element contents were determined in core NJ008 collected from the uppermost ca. 40 cm in a steel company in southwest Nanjing. the results showed that magnetic susceptibility (χ), saturation isothermal remanent magnetization (SIRM) and anhysteretic remanent magnetization (ARM) were enhanced in the uppermost 20 cm, with a mean magnetic susceptibility value of 112.5×10-8 m3 kg-1. Below 20 cm, χ decreased sharply with a mean value of 27.8×10-8m3 kg-1. Low-coercivity minerals such as magnetite dominate in arable soils, while the relative content of antiferromagnetic minerals increases below 20 cm. Heavy metals (Ni, Cu, Fe, Pb, V, and Zn) have similar vertical trends as χ. Principal component analysis reveals common high loadings of the same factor for magnetic concentration parameters (χ, ARM, and SIRM) and elements (Ni, Cu, Fe, Pb, V, and Zn) with an excellent linear correlation (0.69≤R≤0.98) between them. Magnetic susceptibility of paddy soil core NJ013, which had the same parent material as NJ008 but was far from pollution sources, showed stable values of magnetic concentration parameters along the whole core. Absolute values correspond to the so-called magnetic background value (below 20 cm) of NJ008. this indicates that pesticide and fertilizer had little effect on magnetic signals of the upper part of core NJ008 and the extremely enhanced magnetic concentration parameters originate from the steel company emission. Although, the arable soil does not reveal the pollution history and transportation due to annual ploughing, the significant linear relationship between magnetic concentration parameters and heavy metal contents suggests that magnetic parameters can serve as a proxy for quickly detecting soil metallic pollution and estimating the extent of contamination.

关键词： steel company soil heavy metal magnetic parameters

Groundwater protection:What can we learn from Germany?

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第3期9卷 227-231页

作者： Klaus-Dieter BALKE Institute for Geosciences University of TübingenSigwartstr.10D-72076 TübingenGermany

For drinking water security the German waterworks proceed on a comprehensive concept,i.e.,the protection of all the regions from the recharge area to the *** includes the protection of the recharge area by a precautionary management,a safe water treatment,a strict maintenance of the water distribution network,continuous control and an intensive training of *** protection zones together with effective regulations and control play a very important *** protection zones with different restrictions in land-use are *** in reservoirs and lakes is also protected by Surface Water Protection *** the surrounding area the land-use is controlled,*** treatment is necessary if acidification happens caused by acid rain,or eutrophication caused by the inflow of *** important is the collaboration between waterworks and the farmers cultivating land in the recharge area in order to execute water-protecting ecological farming with the aim to reduce the application of fertilizers and plant protection *** financial losses have to be compensated by the waterworks.

关键词： Drinking water security Germany Groundwater protection zone Water protection