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STRUCTURE OF [W（H）2（F）(OH2)（PMe2）4]F

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Chinese Journal of Structural Chemistry 1986年第1期 23-27页

作者： Keith Prout Chemical Crysatallography Laborntory oxford unlversityt oxford U.K.

Mr = 546.3, orthorhombic, space group Cmc21, a = 14.223(4), b = 12.907(3), c = 12.343(4) A, V = 2265.746 A3, Z = 4, DC = 1.601 Mg.m-3, λ= 0.7106 A, μ(MoK(?)) = 56.86 cm-1, F(OOO) = 1048. Final R = 0.044 for 1937 observed reflections. Cation [W(H)2(F)(OH2)(PMes)4]4 has a mirror symmetry, an equatorial belt of four PMe3 groups and mutually syn fluoride and water Ugands. The mean W-P length is 2.462 (A) and P-C 1.83 (A). From the dimensions of the metal, fluoride and water system ( W(1)-F(1) = 2.08(1), W(1)-0(1) - 2.084(9), F(2)-O(1) = 2.59(2) A and F(2)-W(1)-O(1) - 76.7(4)°) an in-terligand hydrogen bond was assumed. The ligand water molecule also makes an H-bonded contact with the fluoride counter ion.

关键词： PMe2 STRUCTURE OF OH2 length

Universal adaptive optics for microscopy through embedded neural network control

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Light(Science & Applications) 2023年第12期12卷 2597-2609页

作者： Qi Hu Martin Hailstone Jingyu Wang Matthew Wincott Danail Stoychev Huriye Atilgan Dalia Gala Tai Chaiamarit Richard M.Parton Jacopo Antonello Adam M.Packer Ilan Davis Martin J.Booth Department of Engineering Science University of OxfordOxfordUK Department of Biochemistry University of OxfordOxfordUK Department of Physiology Anatomyand GeneticsUniversity of OxfordOxfordUK

The resolution and contrast of microscope imaging is often affected by aberrations introduced by imperfect optical systems and inhomogeneous refractive structures in *** optics(AO)compensates these aberrations and restores diffraction limited performance.A wide range of AO solutions have been introduced,often tailored to a specific microscope type or *** now,a universal AO solution-one that can be readily transferred between microscope modalities-has not been *** propose versatile and fast aberration correction using a physics-based machine learning assisted wavefront-sensorless AO control(MLAO)*** previous ML methods,we used a specially constructed neural network(NN)architecture,designed using physical understanding of the general microscope image formation,that was embedded in the control loop of different microscope *** approach means that not only is the resulting NN orders of magnitude simpler than previous NN methods,but the concept is translatable across microscope *** demonstrated the method on a two-photon,a three-photon and a widefield three-dimensional(3D)structured illumination *** showed that the method outperformed commonly-used modal-based sensorless AO *** also showed that our ML-based method was robust in a range of challenging imaging conditions,such as 3D sample structures,specimen motion,low signal to noise ratio and activity-induced fluorescence ***,as the bespoke architecture encapsulated physical understanding of the imaging process,the internal NN configuration was no-longer a"black box",but provided physical insights on internal workings,which could influence future designs.

关键词： optics illumination correction

Mechanical Properties of Si and Some d-electron Metals:Force Laws, Electron Correlation and Bond-breaking

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Journal of Materials Science & Technology 1999年第4期15卷 289-295页

作者： N.H.MarChoxford University oxford EnglandPrivate address: 6 Northcroft Road, Egham, Surrey,TW20 ODU, England Univ oxford Oxford England

The coordination-dependent force fleld of TersofF for covalently bonded Si has been used tocalculate the cleavage force as a function of interplanar separation and hence to estimate surfaceenergies. This force field is already fitted to density functional results. The relation to bond-breaking and electron correlation will be emphasized. Finnis-Sinclair-type many-body potentialshave then been used to treat some d-electron metals. In particular, results for cleavage forcein bcc Fe will be presented, and also some calculations as two perfectly planar Fe surfaces arerubbed together' at different interplanar separations. Finally, lattice dynamical models for thesteady-state propagation of a screw dislocation, and then of a crack, will be used, again within abond-breaking type of force field. For the screw dislocation propagation. a solitary wave equationis shown to follow in the 'almost continuum' limit. Energy radiated by phonons as the dislocationmoves can thereby be calculated.

关键词： Mechanical Properties of Si and Some d-electron Metals Rev Electron Correlation and Bond-breaking Si

NONLINEAR DIFFRACTION OF BICHROMATIC WAVES BY A VERTICAL CYLINDER

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Journal of Hydrodynamics 1997年第4期9卷 97-110页

作者： J.B.Huang, R. Eatock TaylorDepartment of Engineering Science, University of oxford, Parks Road, oxford, OX13PJ, UK. Univ of oxford Oxford United Kingdom

We present in this paper a semi-analytical solution for second-order wave diffraction by a vertical circular cylinder in bichromatic waves. On the base of the usual assumption of an irrotational flow, the wave-diffraction problems at second-order sum-frequency and difference-frequency are considered. The corresponding second-order diffraction potentials are decomposed into three parts, these are associated with the second-order incident wave, the quadratic forcing terras on the free-surface due to the first-order potential, and the linearised free-wave component resulting from the boundary condition on the body surface. A particular solution which exactly satisfies the inhomogeneous free-surface condition has been derived. Numerical results for the quadratic transfer functions of the second-order force components are given, and are compared with those obtained using numerical solutions (Kim & Yue, 1990,Moubayed & Williams 1995). These quadratic functions are useful in calculating the exciting forces on a circular cylinder of large dimension, fixed in irregular wave fields.

关键词： bichromatic waves nonlinear diffraction,cylinder

An institution theory of formal meta-modelling in graphically extended BNF

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Frontiers of Computer Science 2012年第1期6卷 40-56页

作者： Hong ZHU Department of Computing and Communication Technologies Oxford Brookes University Oxford UK

Meta-modelling plays an important role in model driven software development. In this paper, a graphic exten- sion of BNF （GEBNF） is proposed to define the abstract syn- tax of graphic modelling languages. From a GEBNF syntax definition, a formal predicate logic language can be induced so that meta-modelling can be performed formally by spec- ifying a predicate on the domain of syntactically valid mod- els. In this paper, we investigate the theoretical foundation of this meta-modelling approach. We formally define the se- mantics of GEBNF and its induced predicate logic languages, then apply Goguen and Burstall＇s institution theory to prove that they form a sound and valid formal specification lan- guage for meta-modelling.

关键词： meta-modelling modelling languages abstractsyntax semantics graphic extension of BNF (GEBNF) for-mal logic institution

Increased β-Cyanoalanine Nitrilase Activity Improves Cyanide Tolerance and Assimilation in Arabidopsis

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Molecular Plant 2014年第1期7卷 231-243页

作者： Brendan O'Leary GaU M. Preston Lee J. Sweetlove Department of Plant Sciences University of Oxford Oxford UK

Plants naturally produce cyanide （CN） which is maintained at low levels in their cells by a process of rapid assimilation. However, high concentrations of environmental CN associated with activities such as industrial pollution are toxic to plants. There is thus an interest in increasing the CN detoxification capacity of plants as a potential route to phytoremediation. Here, Arabidopsis seedlings overexpressing the Pseudomonas fluorescens β-cyanoalanine nitrilase pinA were compared with wild-type and a β-cyanoalanine nitrilase knockout line （△Atnit4） for growth in the presence of exogenous CN. After incubation with CN, ＋PfpinA seedlings had increased root length, increased fresh weight, and decreased leaf bleaching compared with wild-type, indicating increased CN tolerance. The increased tolerance was achieved without an increase in β-cyanoalanine synthase activity, the other enzyme in the cyanide assimilation pathway, suggesting that nitrilase activity is the limiting factor for cyanide detoxification. Labeling experiments with [^13C] KCN demonstrated that the altered CN tolerance could be explained by differences in flux from CN to Asn caused by altered β-cyanoalanine nitrilase activity. Metabolite profiling after CN treatment provided new insight into downstream metabolism, revealing onward metabolism of Asn by the photorespiratory nitrogen cycle and accumulation of aromatic amino acids.

关键词： cyanide β-cyanoalanine cyanide detoxification asparagine metabolism nitrilase

Hebbian plasticity:the elusive missing link at the heart of Alzheimer’s disease pathogenesis?

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Neural Regeneration Research 2023年第1期18卷 123-124页

作者： Alexander F.Jeans Department of Pharmacology University of OxfordOxfordUK

The amyloid cascade hypothesis of Alzheimer’s pathogenesis:The amyloid cascade hypothesis of Alzheimer’s disease(AD)pathogenesis will shortly celebrate its thirtieth birthday(Hardy and Higgins,1992).Based on abundant genetic and biochemical evidence,it proposes that deposition of the amyloid-β(Aβ)peptide in brain parenchyma is an essential upstream trigger in AD pathogenesis that drives a cascade of events,specifically including the recruitment and pathological hyper-phosphorylation of the micro-tubule-associated protein tau,that culminate in derangement of synaptic function and,eventually,neuronal death.

关键词： pathogenesis Alzheimer eventually

Dynamic necking of a near α titanium alloy at high strain rates:Experiments and modelling

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Defence Technology（防务技术） 2021年第4期17卷 1126-1134页

作者： Long-hui Zhang Antonio Pellegrino Nik Petrinic Department of Engineering Science University of OxfordOxfordOX13PJUK

The tensile behaviour of near a Ti3Al2.5 V alloy,conceived for applications in aerospace and automotive engineering,is characterized from quasi-static to high strain *** material is found to present noticeable strain rate *** dynamic true strain rate in the necking cross-section reaches values up to ten times higher than the nominal strain *** is also observed that beyond necking the dynamic true stress-strain curves present limited rate *** experimental results at different strain rates are used to determine a suitable constitutive model for finite element simulations of the dynamic tensile *** model predicts the experimentally macroscopic force-time response,true stress-strain response and effective strain rate evolution with good agreement.

关键词： Nearαtitanium alloy High strain rate Locking effect Constitutive modeling Finite element simulation

Human cancergermlineantigen-specific cytotoxicTcell-what canwelearnfrompatient

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Cellular & Molecular Immunology 2020年第7期17卷 684-692页

作者： Megat Abd Hamid Yanchun Peng Tao Dong Nufield Department of Medicine Chinese Academy of Medical Science Oxford Institute(COI)University of OxfordOxfordUK MRC Human Immunology Unit MRC Weatherall Institute of Molecular MedicineUniversity of OxfordOxfordUK

In this review,we will highlight the importance of cancer germline antigen-specific cytotoxic CD8^(+) T lymphocytes(CTL)and the factors affecting antitumor CTL *** light of cancer immunotherapy,we will emphasis the need to further understand the features,characteristics,and actions of modulatory receptors of human cancer germline-specific CTLs,in order to determine the optimal conditions for antitumor CTL responses.

关键词： cytotoxic T cell immune check point receptor immune therapy T cell receptor cancer antigen