一种高性能太阳敏感器复合光学系统设计

以夫朗禾费衍射理论为基础,结合微透镜,设计了一种高性能的数字式太阳敏感器复合光学系统。分析了光学系统的组成,建立了光学系统的数学模型,设计了光学系统的焦距、孔径和微透镜参量,并进行了成像的数值仿真。仿真结果表明,与基于掩模的光学系统相比,这种新型的复合光学系统成像光斑能量分布集中,保证计算光斑中心位置的高精度,使敏感器具有大视场和高精度的特点。     

2,2-双(4-氯-2-氟苄基)丙二酸二乙酯的晶体结构和密度泛函理论研究

标题化合物是一个重要的精细化工中间体,可用于制备嘧啶类、吡唑类等产品.本文利用红外光谱(IR)、质谱(MS)、核磁共振氢谱(1 H NMR)、核磁共振碳谱(13 C NMR)和X-射线单晶衍射对此化合物进行了表征,并在B3LYP/6-311G(d,p)模式下使用密度泛函理论(DFT)计算了此化合物的最稳定晶体结构以及最...     

Chemical composition and phase identification of sodium titanate nanostructures grown from titania by hydrothermal processing

Fine titanium dioxide particles were hydrothermally treated in a sodium hydroxide aqueous solution. The treatment extended from 1 to 6 days leading to belt-like and wire-like structures of a metastable phase of sodium titanate, with typical widths and diameters between 8 and 40 nm, and lengths from 100 nm to several micrometers. These conclusions are supported by X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and high resolution transmission electron microscopy. The latter method revealed two set of space fringes with characteristic distances of 0.29 and 0.34 nm. These distances could correspond to the lattice spacing of and planes in Na₂Ti₆O₁₃ compounds. The nanomaterial was found to be stable up to temperatures as high as 200 or depending on the reaction time and the concentration.     

ICF系统中全息透镜聚焦特性及衍射效率分析

根据全息透镜的工作原理,利用光线追迹法对其聚焦特性进行了理论分析。使用标量衍射法分析了全息透镜的衍射效率,讨论了不同的光栅槽型对其衍射效率的影响。对分析过程中所涉及到的有关近似处理方法的使用和影响进行了说明,讨论了全息透镜用作取样光栅的优点。     

Synthesis, Structure and H+/K+-ATPase Inhibitory Activity of Novel Triazolyl Substituted Tetrahydrobenzofuran Derivatives via One-pot Three-component Click Reaction

Eleven triazolyl substituted tetrahydrobenzofuran derivatives were synthesized in high yields as novel H⁺/K⁺‐ATPase inhibitor via one‐pot CuI‐catalyzed three‐component click reaction of azide, secondary amine and 3‐bromopropyne under mild conditions in water. Their structures were characterized by NMR, IR, ESI‐MS, elemental analysis and single‐crystal X‐ray diffraction analysis. Most of the target compounds exhibited better H⁺/K⁺‐ATPase inhibitory activity than commercial omeprazole with IC₅₀ values less than 15 µmol·L^?1. The initial structure‐activity analysis suggested that the triazole substituted by cycloalkyl, aromatic ring or O‐containing side‐chain seemed to be beneficial for enhancing the activity.     

Structural characteristics and residual stresses in oxide films produced on Ti by pulsed unipolar plasma electrolytic oxidation

Oxide films, 7–10 µm thick, were produced on commercially pure titanium by plasma electrolytic oxidation in a sodium orthophosphate electrolyte using a pulsed unipolar current with frequency (f) and duty cycle (δ) varying within f = 0.1–10 kHz and δ = 0.8–0.2, respectively. The coatings comprised a mixture of an amorphous phase with nanocrystalline anatase and rutile phases, where the relative rutile content range was 17–25 wt%. Incorporation of phosphorus from the electrolyte into the coating in the form of PO₂ ^–, PO₃ ^2– and PO₄ ^3–, as demonstrated by EDX and FT-IR analyses, contributed to the formation of the amorphous phase. Residual stresses associated with the crystalline coating phase constituents were evaluated using the X-ray diffraction sin² ψ method. It was found that, depending on the treatment parameters, internal direct and shear stresses in anatase ranged from–205 (±17) to–431 (±27) MPa and from–98 (±6) to–145 (±10) MPa, respectively, whereas the rutile structure is comparatively stress-free.     

Convergent-beam electron diffraction of CaZr4O9, a complex zirconia alloy phase

The point-group and space-group symmetry of the controversial fluorite-based stoichiometric superlath phase of ø₁ (CaZr₄O₉: Z=16), considered to be a coherently-intergrown subphase of lime-stabilized zirconia, is examined. Using convergent-beam and selected-area electron diffraction, it is determined that the space group of ø₁ is C2/c, in apparent agreement with earlier studies utilizing other diffraction techniques.     

Search for a precursor crystal-to-crystal phase transition to amorphization in α-GeO2 and α-AlPO4 under pressure

Recent X-ray diffraction studies on α-quartz (SiO₂) by Kingmaet al [1], have shown the occurrence of a reversible, crystalline-to-crystalline, phase transition just prior to amorphization at ≈ 21 GPa. This precursor transition has also been confirmed by our recent molecular dynamics simulation study [2]. In order to investigate the possibility of a similar behaviour in other isostructural compounds, which also undergo pressure induced amorphization, α-GeO₂ and α-AlPO₄ (berlinite form) were studied using energy dispersive X-ray diffraction. In either of these materials, no such phase transition is detected prior to amorphization. The onset of amorphization and its reversal is found to be time dependent in GeO₂.     

镓一镁二元相图研究

本文用两种差热分析方法即“一步法”和“二步法”以及多晶X-射线衍射法对镓-镁二元系相图进行了研究.修正了前人的工作. 为了考察该二元体系的金属间化合物是否以镓原子多面体簇状结构存在,作者对富镓部分相图(镓原子百分含量大于71.4％)进行了较为细致的研究.在三种不同比例下(含镓量分别为85at.％、90at.％、95at.％)合成,分离得到了颗粒状晶体.对这些晶体进行了差热分析和多晶X-射线研究.分析结果表明:从这三种不同比例的合金中分离得到的晶体为同一金属间化合物Mg_2Ga_5,也是该二元系镓含量最高的金属间化合物.考察Ga-Mg体系中存在的五种金属间化合物的结构,未能发现镓原子以多面体簇状结构存在的现象.