Crystal Structures,Thermal Behavior Analysis and Thermal Safety of Two Energetic Salts of Hydrazinyl-1,2,4,5-tetrazine with 3,5-Dinitrosalicylic Acid

Two energetic salts, DPHT·DNS·H₂O(1) and DHT·2DNS·2H₂O(2)[DPHT=3-(3,5-dimethyl-1H-pyrazol-1-yl)-6-hydrazinyl-1,2,4,5-tetrazine; DHT=3,6-dihydrazinyl-1,2,4,5-tetrazine], were synthesized from S-tetrazine with 3,5-dinitrosalicylic acid(DNS). Compounds 1 and 2 were structurally characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction. The thermal behavior of the title compounds was studied by differential scanning calorimetry(DSC) and thermogravimetry(TG). The non-isothermal decomposition kinetics of compound 2 were investigated. The self-accelerating decomposition temperature, thermal ignition temperature, and critical temperatures of thermal explosion were obtained to evaluate the thermal safety of compound 2. The results show compounds 1 and 2 decompose at 150.8 and 179.2℃, respectively. The T_SADT and T_b of compound 2 are higher than those of DHT, which indicates compound 2 is a potential candidate for energetic materials that have good thermal stability.     

考虑视轴方向的个性化眼模型的构建

包含更多人眼解剖学特性的个性化眼模型具有重要的实验和临床意义。由角膜地形图计算了8只人眼视轴与光轴之间的夹角,水平分量平均值为4.23°±1.51°,竖直分量平均值为-0.40°±1.27°。根据视轴与光轴之间的夹角、角膜地形数据、眼内各部分轴向间距和人眼波像差,运用光学设计软件Zemax分别为这8只人眼构建了考虑视轴方向的个性化眼模型。在此基础上,计算了波前引导的个性化角膜切削深度,并与光程差方法计算的切削深度进行了比较。在切削光区中心处,两者相差不大,平均值为(0.09±0.04)μm;随着半径增大,两者之间的差值逐渐增大。对于所研究的实例,光区外围处的最大差值为0.59μm。个性化眼模型为设计波前引导的个性化角膜切削方案提供了一个有效工具。     

激光原位角膜磨镶手术后不良症状的光学分析

测量了准分子激光原位角膜磨镶(LASIK)手术后人眼的单色像差。并根据术后症状,将所有数据分类为视物星芒状组、单眼复视组、视物雾状组和参考组。视物星芒状组和视物雾状组的三阶和四阶泽尼克(Zernike)像差的均方根(RMS)值明显大于无症状的参考组。术后有不良症状各组的人眼的调制传递函数(MTF)明显低于参考组的调制传递函数。在明视觉条件下,四阶像差特别是对称性的泽尼克球差,对调制传递函数的影响大;而在暗视觉条件下,三阶像差特别是非对称性的泽尼克彗差对调制传递函数的影响大。四阶以上的高阶像差对各有症状组的调制传递函数曲线有影响,而这些高阶像差对参考组的调制传递函数已无明显影响。像差的均方根值和调制传递函数曲线是研究术后不良症状的较有效光学手段。     

基于个性化人眼模型的大视场波像差特性的研究

大视场波前像差对人眼光学系统的影响不容忽视。运用Zemax光学设计软件分别为8只正常人眼构建了个性化的人眼模型,该人眼模型由实际测量的人眼波前像差数据、角膜地形数据及眼内各部分轴向间距数据优化得来,与个体人眼具有相同的光学特性。在此基础上,分析了人眼颞侧方向0°,10°,20°,30°,40°,50°视场的离轴像差随视场角的变化趋势,得出边缘视觉比中央视觉质量差主要来源在于像散与彗差。四阶以上的高阶像差随着视场角的改变,变化不大。将个性化人眼模型计算得到的大视场波前像差值与用哈特曼夏克(Hartmann-Shack)波前传感器实际测量得到的人眼像差值相比较,两者结果相吻合。     

四烷基胺硅酸盐水溶液的研究

三甲基硅烷化气相色谱(TMS-GC)法研究了四甲基胺、四乙基胺、四丙基胺和四丁基胺硅酸盐水溶液中硅酸根离子聚合状态的分布,并对四甲基胺硅酸盐与硅酸钠溶液中硅酸根离子结构的差异进行了比较,从中得到合成沸石分子筛模板剂的作用原理。     

Synthesis and electrochemical characterization of β-tetra-(2-isopropyl-5-methylphenoxylphthalocyaninato)titanium(IV) Oxide

A β-4-(2-isopropyl-5-methylphenoxylphthalocyaninato)titanium(IV) oxide (TiOPc) was prepared and characterized by MS, ¹H NMR, and elemental analysis. Cyclic voltammograms show that this TiOPc has two quasi-reversible reduction couples and two quasi-reversible to irreversible oxidations processes. The first reductions are two-electron processes, confirmed by spectroelectrochemistry to be due to Ti^IVPc²⁻/Ti^IIIPc³⁻ redox processes. The second reductions are two-electron processes during which Ti^IIIPc³⁻ was reduced to Ti^IIIPc⁵⁻ species. Spectroelectrochemistry showed that oxidation occurs at the ring during the first oxidation. However, spectroelectrochemistry also showed that upon the second oxidation, the molecule decomposes. Chronocoulometry confirmed transfer of two electrons at the first and second reduction steps. Published in Elektrokhimiya in Russian, 2008, Vol. 44, No. 12, pp. 1466–1472. The text was submitted by author in English.     

An intravascular loopless monopole antenna for vessel wall MR imaging at 3.0 T

The purpose of this study was to develop a novel intravascular loopless monopole antenna (ILMA) design specifically for imaging of small vessel walls. The ILMA consisted of an unshielded, low-friction guide wire and a tuning/matching box. The material of the guide wire was nitinol and it was coated with polyurethane. Because the guide wire was unshielded, it could be made thinner than the coaxial cable-based loopless intravascular antenna design. The material of the box was aluminum. In this study, the diameter of the guide wire was 0.5 mm and the length was 58.7 mm. The ILMA was used as a receiving antenna and body coil for transmission. To verify the feasibility of the ILMA, in vitro and in vivo experiments were performed on a 3.0-T magnetic resonance (MR) scanner. In vitro tests using the ILMA indicated that the proposed design could be used to image target vessel walls with a spatial resolution of 313 μm at the frequency coding direction and more than 100 mm of longitudinal coverage. In vivo tests demonstrated that the images showed the vessel walls clearly by using the ILMA and also indicated that the ILMA could be used for small vessels. The proposed antenna may therefore be utilized to promote MR-based diagnoses and therapeutic solutions for cardiovascular atherosclerotic diseases.     

The origin of reflection loss peaks in the double-layer electromagnetic wave absorber

We investigated the origin of reflection loss (RL) peaks of Co₂Z particle composite (t mm)/fake-shaped carbonyl iron (CI) particle composite (1.5 mm) double-layer absorbers backed by a perfect conductor in 0.1–18 GHz. The RL peak frequency in the low frequency region remains unvariable and the RL peak in the high frequency region moves to lower frequency with the increase of Co₂Z particle composite thickness. The investigation results indicated that the two RL peaks come from the quarter-wavelength cancellation at the interface from Co₂Z particle composite to CI particle composite and the interface from air to Co₂Z particle composite, respectively.