软X射线条纹相机的静态性能研究

软X光扫描相机是对软X光时间持性进行研究的主要诊断工具,我们利用 同步辐射作为光源,对它的静态性能：能量响应、增益等性能进行了相对标定,给出了软X 光条纹相机的能量响应曲线和增益特性曲线,并与利用B.L.Henke的经验公式计算给出的响 应曲线比较,其结果与理论较符合。     

高散射介质中光子扩散成像的线性平移不变性

运用微扰理论探讨了光子扩散成像的线性平移不变性,阐明了光子扩散成像用于生物组织这一高散射介质结构与功能成你的信号形成机理.光子扩散成像所得的图像是介质内部异常结构通过光子扩散成像系统的响应.光子扩散成像系统的作用可用一个脉冲响应函数来表征.     

A convenient synthesis of 5‐(O,O‐dialkylphosphoryl)‐4‐aryl‐3,4‐dihydropyrimidin‐2(1H)‐ones

A general and convenient route for the synthesis of dihydropyrimidines bearing the phosphoryl moiety by a one‐pot cyclocondensation involving aldehydes, urea, and O,O‐dialkyl‐2‐oxo‐propanephosphonates, using ytterbium triflate as catalyst, is reported. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:13–17, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10058     

Shear‐Induced Morphological Change in PP/LLDPE Blend

The morphology of a PP/LLDPE blend (50 : 50) by phase dissolution at high shear rate combined with dynamic packing injection molding at low shear rate was investigated by atomic force microscopy. Phase dissolution under high shear rate is manifested by a co‐continuous two‐phase structure that could be broken down to an island‐like structure when a low shear rate is applied via dynamic packing injection molding or simply by manual deformation.     

多相催化过硫酸盐工艺处理水环境中有机污染物的非自由基过程

20世纪80年代至今,水处理技术中的高级氧化过程(AOP)已被广泛研究及应用。然而水体中的有机污染物仍因种类繁多和降解难易不同困扰着研究者们,因此对于AOP的机理过程需要更深入的分析认识,以利于技术的进一步发展及应用。AOP中的过硫酸盐氧化工艺近年来得到大量关注,其自由基机理的关键活性物种是·OH 和·SO₄^-。非自由基机理分为¹O₂氧化和PS直接氧化(也称电子转移),某些体系中高价态金属也直接或间接地参与氧化过程。但非自由基过程的发生机理及优势特点仍存在争议。本文综述了基于多相催化过硫酸盐高级氧化过程处理水中有机污染物的最新研究,阐述反应机理及其分析手段,并指出当前研究可能存在的问题。对于过硫酸盐高级氧化工艺中非自由基过程的未来研究方向及应用前景提出展望。     

镍基合金掺杂W、Mo原子在γ/γ＇相界面扩散机理研究

运用基于密度泛函理论的第一性原理,研究掺杂W、Mo在镍基高温合金的沉淀强化γ′相分配差异的因素.通过VASP软件,建立γ′-Ni₃(Al_3/8Ti_5/8)相的体系模型,选取非等效位置的不同阵点,计算W、Mo原子在不同位置的替代形成能,分析W、Mo在γ′相的占位倾向;计算掺杂W、Mo原子前后,界面的吸附能,研究掺杂W、Mo对相界的影响;计算W、Mo原子从γ向γ′相扩散,获得W、Mo扩散的路径与势垒.结果表明,W、Mo的掺杂优先替代γ′-Ni₃(Al_3/8Ti_5/8)相5号Al原子,并提高相界的稳定性;分配的差异是W相比于Mo替代γ′相位置的Al原子更易形成空位,而γ相中的Ni原子较难形成空位,且逆扩散所需能量更多导致的.     

A novel dendritic anion conductor: quaternary ammonium salt of poly(amidoamine) (PAMAM)

The quaternary ammonium salts of dendritic poly(amidoamine) generations 2 and 3 are prepared by methylation and quaternization with methyl iodide. The obtained dendritic anion conductors exhibit a conductivity of 10^–5–10^–6 S·cm^–1 at ambient temperature. The plots of conductivity vs. temperature are curves with the lowest point around 58°C, which appear to exhibit a substantially different conductive law compared with ordinary linear or comb-like polyelectrolytes.     

Diallyl Trisulfide,the Antifungal Component of Garlic Essential Oil and the Bioactivity of Its Nanoemulsions Formed by Spontaneous Emulsification

The aim of this study was to evaluate the chemical compounds of garlic essential oil (EO), and determine the antifungal efficacy of garlic EO and its major components, diallyl trisulfide and its nanoemulsions against wood-rotting fungi, Trametes hirsuta and Laetiporus sulphureus. GC-MS analysis revealed that the major constituents of garlic EO were diallyl trisulfide (39.79%), diallyl disulfide (32.91%), and diallyl sulfide (7.02%). In antifungal activity, the IC₅₀ value of garlic EO against T. hirsuta and L. sulphureus were 137.3 and 44.6 μg/mL, respectively. Results from the antifungal tests demonstrated that the three major constituents were shown to have good antifungal activity, in which, diallyl trisulfide was the most effective against T. hirsuta and L. sulphureus, with the IC₅₀ values of 56.1 and 31.6 μg/mL, respectively. The diallyl trisulfide nanoemulsions showed high antifungal efficacy against the examined wood-rotting fungi, and as the amount of diallyl trisulfide in the lipid phase increases, the antifungal efficacy of the nanoemulsions increases. These results showed that the nanoemulsions and normal emulsion of diallyl trisulfide have potential to develop into a natural wood preservative.     

Bio‐orthogonal AIE Dots Based on Polyyne‐Bridged Red‐emissive AIEgen for Tumor Metabolic Labeling and Targeted Imaging

In this work, we aim to develop cancer cell‐targeting AIE dots based on a polyyne‐bridged red‐emissive AIEgen, 2TPE‐4E, through the combination of metabolic engineering and bio‐orthogonal reactions. Azide groups on a tumor were efficiently produced by intravenous injection of Ac4ManNAz and glycol‐metabolic engineering. These bio‐orthogonal azide groups could facilitate the specific targeting of DBCO‐AIE dots to the tumor cells undergoing metal‐free click reaction in vivo. The efficiency of this targeting strategy could be further improved with the development of new bio‐orthogonal chemical groups with higher reactivity and a large amount of AIEgens could be delivered to the tumor for diagnosis.