自由曲面光学虚拟制造与检测系统的探讨

自由曲面光学产品设计、制造与检测的工艺流程，通常采取试凑法逐次逼近。由于加工 检测 再加工，循环往复，既费时，成本又高，产生了瓶颈问题。为了解决此弊端，本文运用虚拟制造技术，提出光学虚拟制造的基本构想，即虚拟制造系统结构模型，给出光学系统虚拟原型的构成和光学系统成像质量虚拟检测系统的构成，讨论光学成像质量的仿真检测以及敏度分析方法。研究结果表明：运用虚拟制造与检测技术，可缩短研发周期，降低成本，优化工艺并提高产品质量。     

A spectro-microscopic study of the reactive phase separation of Au + Pd and O on Rh(1 1 0)

Reorganization of Au + Pd submonolayers on a Rh(1 1 0) surface occurring during the water formation reaction has been observed and characterized by low energy electron microscopy (LEEM) and X-ray photoemission electron microscopy (XPEEM). The results demonstrate segregation of Au + Pd and oxygen into separate surface phases, the morphology and size of the O and Au + Pd patterns being governed by the reaction parameters and adsorbate coverage. At moderate Au + Pd coverages and temperatures in the range 760-860 K, lamellar periodic Au + Pd/O micro-structures are generated. The results are interpreted in terms of kinetic and thermodynamic considerations.     

Formation of regular surface-supported mesostructures with periodicity controlled by chemical reaction rate

We report a LEEM and XPEEM study of the formation of a variety of stationary two-dimensional metallic and oxygen structures in Au and Au + Pd adlayers on Rh(110) during water formation reaction. They result from chemically frozen spinodal decomposition and are created, preserved, or reversibly modified by tuning the reaction conditions. The wavelength of lamellar structures obtained at intermediate metal coverage is found to obey a power scaling law with respect to the reaction rate.     

Large scale free energy calculations for blind predictions of protein–ligand binding: the D3R Grand Challenge 2015

We describe binding free energy calculations in the D3R Grand Challenge 2015 for blind prediction of the binding affinities of 180 ligands to Hsp90. The present D3R challenge was built around experimental datasets involving Heat shock protein (Hsp) 90, an ATP-dependent molecular chaperone which is an important anticancer drug target. The Hsp90 ATP binding site is known to be a challenging target for accurate calculations of ligand binding affinities because of the ligand-dependent conformational changes in the binding site, the presence of ordered waters and the broad chemical diversity of ligands that can bind at this site. Our primary focus here is to distinguish binders from nonbinders. Large scale absolute binding free energy calculations that cover over 3000 protein–ligand complexes were performed using the BEDAM method starting from docked structures generated by Glide docking. Although the ligand dataset in this study resembles an intermediate to late stage lead optimization project while the BEDAM method is mainly developed for early stage virtual screening of hit molecules, the BEDAM binding free energy scoring has resulted in a moderate enrichment of ligand screening against this challenging drug target. Results show that, using a statistical mechanics based free energy method like BEDAM starting from docked poses offers better enrichment than classical docking scoring functions and rescoring methods like Prime MM-GBSA for the Hsp90 data set in this blind challenge. Importantly, among the three methods tested here, only the mean value of the BEDAM binding free energy scores is able to separate the large group of binders from the small group of nonbinders with a gap of 2.4 kcal/mol. None of the three methods that we have tested provided accurate ranking of the affinities of the 147 active compounds. We discuss the possible sources of errors in the binding free energy calculations. The study suggests that BEDAM can be used strategically to discriminate binders from nonbinders in virtual screening and to more accurately predict the ligand binding modes prior to the more computationally expensive FEP calculations of binding affinity.     

Allyl complexes of molybdenum with Schiff base ligands. The crystal structures of [MoCl(CO)2{N(C6H4-2-OMe)C(Me)C5H4N}(η-C3H5)] and [MoCl(CO)2{N(Me)C(Ph)C5H4N}(η-C3H5)] are described

Treatment of the molybdenum tetracarbonyl complexes of [Mo(CO)₄L₂] (L₂=pyridyl amine Schiff base ligands) with allyl chloride in refluxing THF afforded η³-allyl complexes [MoCl(CO)₂L₂(η³-allyl)] (1-9). These complexes have been characterised by various techniques including ¹H-NMR, IR and FABMS spectroscopies and the single crystal X-ray structure determinations of the complexes [MoCl(CO)₂{N(C₆H₄-2-OMe)C(Me)C₅H₄N}(η³-C₃H₅)] (3) and [MoCl(CO)₂{N(Me)C(Ph)C₅H₄N}(η³-C₃H₅)] (4).     

Beam-induced effects in soft X-ray photoelectron emission microscopy experiments

The beam-induced effects, a consequence of the high photon flux density used in soft X-ray photoelectron emission microscopes in operation at the 3rd generation synchrotron sources, are discussed and illustrated using some representative results obtained with the microscopes at the laboratory Elettra. The focus is on the photon-induced charge potential and chemical degradation, which might be a severe problem for photon-sensible specimens. The possible steps to avoid, reduce or even make use of the beam-induced effects are outlined.     

自由曲面光学透镜注射成型误差因素研究

自由曲面光学透镜注射成型误差对其光学性能将产生直接影响。注射成型过程中，注射工艺参数组合的优劣，直接影响成型误差的大小。为了获得高精密度的光学元件，就热塑性塑料的注射温度、模具温度、注射压力、保压压力及保压时间等主要工艺参数，对注射成型误差的影响进行综合研究,并且进行了实验验证。研究结果表明：适当提高注射温度与模具温度，同时采用高压注射、高压保压以及快速保压工艺，可显著降低注塑工件的体积收缩率，显著提高面形精密度，其光学表面面形误差小于0.1μm。可为注射工艺设计提供合理的依据。     

Relationship between nonadiabaticity and damping in permalloy studied by current induced spin structure transformations

By direct imaging we determine spin structure changes in Permalloy wires and disks due to spin transfer torque as well as the critical current densities for different domain wall types. Periodic domain wall transformations from transverse to vortex walls and vice versa are observed, and the transformation mechanism occurs by vortex core displacement perpendicular to the wire. The results imply that the nonadiabaticity parameter beta does not equal the damping alpha, in agreement with recent theoretical predictions. The vortex core motion perpendicular to the current is further studied in disks revealing that the displacement in opposite directions can be attributed to different polarities of the vortex core.     

Rotational Dynamics of Adamantanecarboxylic Acid in Complex with β-cyclodextrin

The reorientation of 1-adamantanecarboxylic acid (AdCA) within the β-cyclodextrin (β-CD) cavity is investigated by means of multiple-field ¹³C NMR relaxation. The dissociation constant describing the complexation equilibrium is determined using translational diffusion measurements for the guest during a titration by the host in D₂O/DMSO solvent mixture. The changes in apparent diffusion properties of AdCA during the titration are at 25 °C well described assuming the formation of a 1:1 complex, whereas at 0 °C the data indicate the presence of a 2:1 (guest:host) complex. The ¹³C NMR relaxation parameters for the AdCA molecule bound inside the β-CD cavity are extracted. Despite the high association constant, indicating a strong interaction between the two molecules, the guest molecule is quite mobile. The reorientation of the bound AdCA at 25 °C can be described by either the Lipari–Szabo or the axially symmetric rotational diffusion model. The motion is extremely anisotropic: the adamantyl group rotates fast around the β-CD symmetry axis, inside its cylindrical cavity. At lower temperature, the relaxation properties are no longer possible to explain using these models. Instead, the data are analyzed using extended, three-step spectral density of Clore et al. [J. Am. Chem. Soc. 112, 4989 (1990)].