均匀沉淀法制备超微细透明氧化铁黄颜料

以FeSO4和CO（NH2）2为原料，采用均匀沉淀法制备了超微细透明氧化铁黄颜料，讨论了反应条件对产品晶粒大小及分布的影响，得出了优化的工艺条件，FeSO4浓度为1.0mol/L。原料磨尔比n[尿素]；n[Fe^2 ]=3.5:1，空气通入量6L/h，复合添加剂用量0.3%。     

根据钻孔资料确定地下岩层产状——通用地质坐标系应用实例(之四)

根据钻孔资料确定地下岩层产状是一个比较复杂的问题。利用赤平极射投影网上的小圆相交方法,可以求得倾斜钻孔资料地下岩层的可能产状,但赤平极射投影网上的小圆作图比较复杂。利用通用地质坐标系可直接在球面投影上计算出两个小圆的交点,能更快更准确地得到结果。     

Reliability investigations in micromechanical devices

Fatigue limited lifetime of micromechanical structures has been investigated. To determine the maximum cycle number up to failure a modified Paris equation has been used to model crack growth under load. Test structures (cantilever beams) with well-defined pre-cracks were externally loaded at resonance frequency. Single crystalline silicon as functional material (bulk micromachining) was investigated. Measured and simulated critical stress intensity factors are strongly correlated for all investigated test structures and for different crack lengths showing the validity of the used model. Lifetime decreases exponentially for loads approaching a critical stress intensity. Using the experimental results determined at test structures and the simulation model, fatigue limited lifetime of micromechanical device with typical, process induced crack distribution can be extrapolated.     

PAMAM/PA6共混合金的结晶结构与性能

研究了不同代数和不同份量的PAMAM树形分子对PAMAM／PA6共混合金力学性能的影响，并用DSC、WAXD对PAMAM／PA6共混合金的结晶结构进行了分析．结果表明，PAMAM在低用量时，可提高PAMAM／PA6的结晶速度，使微晶尺寸变大，对共混合金起增塑作用；而在高用量时则对PAMAM／PA6的结晶过程起抑制作用，使微晶尺寸变小，对共混合金起增强作用．     

Synthesis and characteristics of SiC whiskers with “rosary bead” morphology

SiC whiskers with ″rosary bead″ morphology were synthesized using suitable silicon source and carbon source through solid reaction at the temperature above 1537 K. The diameter and length of the SiC whiskers were about 0.1-1.0 μm and 20-100 μm,respectively. The largest diameter of their enlarged ends of the whiskers was about 0.2-1.0 μm, and it gradually and smoothly decreased to the size of the plain part of the whiskers. The results of X-ray diffraction analysis show that the crystalline structure of the obtained SiC whiskers is β-SiC. It is considered that the SiC whiskers grow via a vapor-solid mechanism.     

灌溉周期对工业大麻秆部分理化性能的影响Ⅱ.灌溉周期对纤维素相对结晶度和晶胞尺寸的影响

为更好利用生物质材料,研究纤维素的相对结晶度和晶胞尺寸及其影响因素,用广角X射线衍射仪,研究了不同灌溉周期（3天浇一次水、14天浇一次水、不浇水）对工业大麻秆纤维素相对结晶度和晶胞尺寸的影响。结果表明在整个生长期中,随着生长期延长纤维素的相对结晶度呈增加趋势,晶胞尺寸呈减小趋势;不同灌溉周期对纤维素相对结晶度和晶胞尺寸影响显著（P≤0.05）;纤维素的物理结构在纤维细胞壁不同层次中是不同的。     

Synthesis and curing of liquid crystalline epoxy resin based on asymmetric mesogen

A novel liquid crystalline epoxy resin (LCER) derived from asymmetric mesogen unit was synthesized. Its structure and liquid crystalline behavior were characterized by hydrogen nuclear magnetic resonance (H‐NMR), differential scanning calorimetry (DSC), polarized optical microscopy (POM). The results indicated that the LCER converted to a nematic phase at 85°C during heating and finally became isotropic at 145°C. The curing behavior and phase behavior of the LCER with 4,4′‐diaminodiphenyl methane and methyl hexahydrophthalic anhydride were also studied by DSC and POM, respectively. Their apparent activation energy (E_a) was evaluated according to the Ozawa's isoconversional method. The results suggested that autocatalytic reaction had occurred in these two systems. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

克拉玛依油田石炭系火山岩区断层封闭性研究

为填补克拉玛依油田火山岩断裂封闭机理及定量评价研究的空白,在解剖典型火山岩油藏的基础上,应用综合因子法,综合考虑断面正压力(σ)、断裂带泥质充填物含量(Rm)、断层紧闭指数(I),结合了流体指数F对克拉玛依地区4条主要断层的封闭性进行评价,结果表明,综合因子Q与断裂封闭性有正相关关系,克拉玛依地区由东南向西北,断裂级别依次减小,断层封闭性逐渐变差。综合因子法的评价结果与实际地质情况较相符,可作为火山岩区断层封闭性的评价方法进行推广。     

Cholesteric monomer and elastomers containing menthyl groups: Synthesis and phase behavior

The synthesis of a new cholesteric monomer ( M_LC) containing menthyl groups and a series of cholesteric elastomers ( LCE₁−LCE₄ ) is described. Their chemical structures and purity were characterized by FTIR, ¹H-NMR, and elemental analyses. The phase behavior and thermal stability were investigated by differential scanning calorimetry, polarizing optical microscopy, X-ray diffraction, and thermogravimetric analysis. By inserting a flexible spacer between the mesogenic core and the terminal menthyl groups, mesomorphism of M _LC was realized. LCE₁−LCE₄ with low content of crosslinking unit exhibited cholesteric phase because of the introduction of the nematic crosslinking unit. This indicates that low levels of chemical crosslinking do not significantly affect the phase behavior and mesomorphism of the elastomers, and reversible mesophase transitions can be observed. In addition, with increasing the content of crosslinking unit, the corresponding T_g decreased for LCE₁−LCE₄ , whereas their T_i did not remarkable change. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparing crystalline silicon from Si-Sn solvent by zone melting directional solidification method

To develop a low cost and highly effective metallurgical route for solar-grade Si production, we investigated the zone melting directional solidification method. In this method, bulk crystalline Si is successfully produced from Si-Sn solvent; this bulk crystalline Si demonstrates a steady growth interface and excellent compositional uniformity. Moreover, the growth rate of bulk crystalline Si along the axial direction increases because the remaining MG-Si serves as Si source to keep the Si-Sn solution saturated with Si atoms, and it is approximately three times larger than that of Si by using the Si-based alloy directional solidification method without Si source. In this work, the evolution of impurity phases segregated in different regions along the axial direction is extensively discussed. The distribution and amount of impurities, including Ca, Al, B, and P, are effectively controlled by this refining method, further improving the quality of bulk crystalline Si.