探测器倾斜的锥束FDK修正重建算法

在锥束工业CT系统中,通常要求射线源焦点、物体旋转中心、平板探测器中心三点在一条直线上,与平板探测器垂直。由于机械的定位误差,探测器定位后会出现一定角度的倾斜现象,如果直接利用平板探测器倾斜后采集的投影数据进行重建,重建结果将会出现偏离,产生伪影。针对该问题,利用系统标定的方法测得探测器倾斜角度,利用机械校正对其进行粗调,利用提出的基于探测器倾斜的FDK修正算法进行微调,经过两次校正可以有效抑制由于平板探测器倾斜造成的伪影,通过实验验证了该方法的可行性。     

电子束选区熔化成形技术及在模具中的应用

基于电子束的选区熔化成形技术利用电子束能量密度高、无反射及真空加工环境无污染等优点，将电子束加工与快速原型制造技术相结合，可以制备传统模具制造技术无法制造的具有内流道和材料梯度的模具。本文结合自行研制的国内第一台电子束选区熔化成形设备的构成及技术路线，阐述了该技术在模具行业中的应用前景，并且采用该技术制备了完全致密的金属三维零件。     

纵向磁记录介质研究进展

综述了纵向磁记录介质研究进展情况,主要针对常用的CoCrX型介质,以及正在开发的SmCo型介质的研究进展情况进行了总结。     

LDPE农用耐候棚膜专用料的配方研究及工业化生产

研究了LDPE农用聚乙烯耐候棚膜专用料的配方及老化问题,介绍了选用母粒掺混法制备专用料的工艺路线。经人工加速老化和扣棚自然老化试验证明,用该专用料吹制的棚膜,其使用寿命可达1.5～2年,比普通膜寿命长3～4倍。     

聚偏二氯乙烯用途及生产技术

介绍聚偏二氯乙烯共聚物性能、品种及主要用途和国内外生产应用概况,分析了国内开发及市场现状提出对开发此类产品的建议。     

由TiOSO4水解—沉淀制备TiO2薄膜

通过控制ＴｉＯＳＯ４的水解－沉淀反应条件，可控制基片上膜层粒子大小及其附着力，适量尿素加入可加快均匀成速度。根据ＳＥＭ断面观察与重量法相比较，表征了膜厚。适当反应条件下，反应１ｈ，干燥－煅烧制得的膜０．２μｍ以上；四次重复反应－煅烧，获得的膜这０．８μｍ以上。     

环保高性能防腐涂料驱动未来市场

介绍了防腐涂料的新品种和防腐体系的选择,指出了我国防腐涂料的发展趋势。     

The effect of partial substitution of Ti with Zr, Cr or V in the Mg35Ti10Ni55 electrode alloy on its electrochemical performance

In this paper, Zr, Cr and V were selected as the partial substitution elements for Ti to form Mg₃₅Ti₅M₅Ni₅₅ quaternary alloys prepared by means of mechanical alloying on the basis of the ternary Mg₃₅Ti₁₀Ni₅₅ electrode alloy previously studied by the authors. It is found that all the three quaternary alloys possess an amorphous main phase and exhibit improved cycling stability than the original ternary Mg₃₅Ti₁₀Ni₅₅. The Zr-substituted alloy has also a higher discharge capacity. X-ray photoelectron spectroscopy (XPS) surface analysis reveals that on the surface of each alloy a multi-component oxide composite film is formed, which is more compact and corrosion resistant than the Mg(OH)₂ film and the (TiO₂)_x(NiO)_y(Mg(OH)₂)_z composite films reported previously. Auger electron spectroscopy (AES) analysis shows that the substituting elements tend to reduce the thickness of the passivation films. The thickness of composite oxide film on the alloys is in the following order: Mg₃₅Ti₁₀Ni₅₅>Mg₃₅Ti₅V₅Ni₅₅>Mg₃₅Ti₅Zr₅Ni₅₅>Mg₃₅Ti₅Cr₅Ni₅₅. The result agrees well with that of the polarization resistances (R_P) values obtained from the electrochemical impedance spectroscopy (EIS) Nyquist diagrams. It demonstrates that the thicker the passivation film is, the higher the R_P is and the more difficultly the charge transfer reaction proceeds. Anodic polarization curves indicate that the addition of Cr and Zr decreases effectively the corrosion current. However, the corrosion of the electrode alloys in the electrolyte is still high and proceeds constantly as the corrosion current remains almost constant during further cycles.     

Biodegradable blend films based on two polysaccharide derivatives and their use as ibuprofen‐releasing matrices

Differential scanning calorimetry (DSC), FTIR, X‐ray diffraction (XRD), and viscosity methods were used to examine the miscibility, interaction, and degradability of cationic guar gum (GG) and sodium carboxymethylcellulose (NaCMC) in their blend films. The experiment results prove that there exist electrostatic interactions and hydrogen bonding between GG and NaCMC. Blend films degrade quicker than pure GG or NaCMC film. Furthermore, the degradation rate of blend films is related to the interactions between GG and NaCMC. Based on the research of blend films as the drug carriers for Ibuprofen, it is found that the blend composition, initial drug concentration, and pH value affect the drug release and the GG/NaCMC blend films have good sustained release performance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3553–3559, 2007     

XPG-800型悬挂式胶片冷却机的研制

介绍最新开发的XPG-800型悬挂式胶片冷却机的设计特点、工作原理、主要技术参数、结构特征，阐述了本机组主要技术改进。