沸石补强硅酮建筑密封胶的应用

考察了用沸石和焙烧沸石作为补强剂用于制备硅酮建筑密封胶的工艺过程,分析了粉体用量对密封胶热稳定性、拉伸强度、断裂伸长率、干燥时间的影响;用扫描电镜(SEM)、X射线衍射(XRD)、氮气吸-脱附等温测试(BET)和脱附孔径测试(BJH)方法对沸石和焙烧沸石的微观形貌、物相、比表面积、孔容和孔径进行了表征;研究结果表明,它们是一种具有多孔结构的铝硅酸盐矿物,主要成分分别为KNa2Ca2(Si29Al7)O72和K(Si3Al)O8,孔径分别为10.68 nm和14.02 nm,孔体积分别为0.465 5 mL/g和0.587 1 mL/g,比表面积分别为153.6 m2/g和191.4 m2/g,孔径分布宽、孔体积和比表面积大有利于补强,焙烧沸石的补强性优于沸石,揭示了它们的补强作用是硅烷偶联剂表面改性、孔道效应和锚固效应共同作用的结果。     

沙特胡富夫2×10 000 t/d熟料线预应力生料均化库仓壁设计介绍

沙特胡富夫2×10 000 t/d熟料生产线工程,共设置了2座单库储量达4万t的大型生料均化库。为了满足业主对裂缝过严控制的质量要求（不大于0.1 mm）并确保施工进度的要求,采用了无粘结后张拉预应力钢筋混凝土筒库方案。文章简要介绍了该库的仓壁结构情况,并详细介绍了无粘结预应力混凝土筒仓的结构设计计算及要注意的问题。     

Solid-state synthesis and effect of temperature on optical properties of Cu-ZnO, Cu-CdO and CuO nanoparticles

Controlling novel morphologies and developing effective doping strategies are two important tasks for advancing ZnO and CdO based nanomaterials. Modulation of band energies through size control offers new ways to control photoresponse and photoconversion efficiencies of the solar cell. The P-type semiconductors of copper oxide and zinc oxide are an important functional material used for photovoltaic cells. CuO is attractive as a selective solar absorber since it has high solar absorbance and a low thermal emittance. This work describes the synthesis and characterization of semiconducting nanoparticles (ZnO, CuO, CdO, Cu-ZnO, Cu-CdO) via one-step, solid-state reaction in the presence of polyethylene glycol 400.Solid-state mechanochemical processing—which is not only a physical size reduction process in conventional grinding but also a chemical reaction that is mechanically activated at the nanoscale during grinding. The present method is a simple and efficient method for the preparation of nanoparticles with high yield at low cost. The structural and chemical composition of the nanoparticles were analyzed by X-ray diffraction, field emission scanning electron microscopy and energy-dispersive spectrometer (FESEM/EDAX). Optical properties and band gap were studied by UV-vis absorption spectra. XRD data has been concluded that the Cu doping induced the lattice constants to change to some extent. These results have showed that the band gap energy decreases with increase in annealing temperature, which can be attributed to the improvement in crystallinity of the samples. The band gap of the Cu-ZnO and Cu-CdO crystals can be tuned in the range of 3.34-3.28 eV and 2.80-2.21 eV respectively, by the use of dopants.     

带压处理焦炉循环氨水总管焊缝开裂

介绍了某公司捣回焦炉循环氨水总管焊缝开裂后,在不停氨水的情况下,采用在开裂焊缝的两侧30 mm处焊上一对法兰,法兰四周用螺栓拉固,促使开裂焊缝合拢,阻止氨水外漏,然后在拉固螺栓的外围打上抱箍,用1:1的水泥砂浆外加8%水玻璃浇注密封,取得了令人满意的效果.     

Derivation of a crack opening deflection relationship for fibre reinforced concrete panels using a stochastic model: Application for predicting the flexural behaviour of round panels using stress crack opening diagrams

This study is aimed at proposing a simple analytical model to investigate the post-cracking behaviour of FRC panels, using an arbitrary tension softening, stress crack opening diagram, as the input. A new relationship that links the crack opening to the panel deflection is proposed. Due to the stochastic nature of material properties, the random fibre distribution, and other uncertainties that are involved in concrete mix, this relationship is developed from the analysis of beams having the same thickness using the Monte Carlo simulation (MCS) technique. The softening diagrams obtained from direct tensile tests are used as the input for the calculation, in a deterministic way, of the mean load displacement response of round panels. A good agreement is found between the model predictions and the experimental results.     

Autogenous healing of engineered cementitious composites at early age

Autogenous healing of early ages (3 days) ECC damaged by tensile preloading was investigated after exposure to different conditioning regimes: water/air cycles, water/high temperature air cycles, 90%RH/air cycles, and submersion in water. Resonant frequency measurements and uniaxial tensile tests were used to assess the rate and extent of self-healing. The test results show that ECC, tailored for high tensile ductility up to several percent and with self-controlled crack width below 60 μm, experiences autogenous healing under environmental exposures in the presence of water. However, the recovery for these early age specimens is not as efficient as the recovery for more mature specimen, for the same amount of pre-damage and exposure to the same environment. Even so, the self-healing for these early age specimens demonstrates high robustness when the preloading strain is limited to 0.3%. This conclusion is supported by the evidence of resonant frequency and stiffness recovery of the healed ECC materials.     

盐酸安非他酮的合成工艺优化

由关键中间体3-氯-α-溴-苯基乙基酮合成盐酸安非他酮。研究了碱、相转移催化剂（PTC）、溶剂及反应时间对盐酸安非他酮产率的影响。得出优化反应条件为：在KOH碱性条件下,以PEG-400为相转移催化剂,乙腈作溶剂,室温反应6 h。优化反应条件下,盐酸安非他酮的产率为87.3%。     

钢带缠绕增强塑料复合软管的有限元分析

提出了一种行之有效的利用有限元法计算螺旋钢带弹性模量的方法,在此基础上,对复合软管整体的单向拉伸、弯曲、扭转载荷下的力学性能进行了数值模拟分析,并与复合软管的实验结果进行了对比,结果表明,数值模拟与实验结果具有较强的一致性,从而验证了数值模拟结果的正确性,为解决复杂结构数值模拟分析中材料属性的确定问题提供了一种有效的方法。     

Preparation and mechanical properties of high‐performance short ramie fiber‐reinforced polypropylene composites

Short ramie fiber (RF) was used to reinforce the polypropylene (PP). The composites were prepared in a twin‐screw extruder followed by injection molding. The experimental results showed that both the strength and the modulus of the composites increase considerably with increasing RF content. The tensile strength and flexural strength are as high as 67 and 80 MPa by the incorporation of ramie up to 30 wt %. To the best of our knowledge, this is one of the best results for short natural fiber‐reinforced PP composites. However, the preparation method in this study is more simple and economic. This short RF‐reinforced PP composites extend the application field for short‐nature fiber‐reinforced PP composites. Morphological analysis revealed that it is the high aspect ratio of the fiber and good interfacial compatibility that result in the high performance of the composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Facile preparation of nylon 6 nanocomposites based on clay reinforcement and core‐shell latex toughening: Morphology,properties, and impact fracture behavior

This work is focused on a facile route to prepare a new type of nylon 6‐based nanocomposites with both high fracture toughness and high strength. A series of nylon 6‐matrix blends were prepared via melting extrusion by compounding with poly (methyl methacrylate‐co‐butadiene‐co‐styrene) (MBS) or poly(methyl methacrylate‐co‐methylphenyl siloxane‐co‐styrene) (MSIS) latices as impact modifier and diglycidyl ether of bisphenol‐A (DGEBA) as compatibilizer. Layered organic clay was also incorporated into above nylon 6 blends for the reinforcement of materials. Morphology study suggests that the MBS or MSIS latex particles could achieve a mono‐dispersion in nylon 6 matrix with the aid of DGEBA, which improves the compatibilization and an interfacial adhesion between the matrix and the shell of MBS or MSIS. High impact toughness was also obtained but with a corresponding reduction in tensile strength and stiffness. A moderate amount of organic clay as reinforcing agent could gain a desirable balance between the strength, stiffness and toughness of the materials, and tensile strength and stiffness could achieve an improvement. This suggests that the combination of organic clay and core‐shell latex particles is a useful strategy to optimize and enhance the properties of nylon 6. Morphology observation indicates that the layered organic clay was completely exfoliated within nylon 6 matrix. It is found that the core‐shell latex particles and the clay platelets were dispersed individually in nylon 6 matrix, and no clay platelets were present in MBS or MSIS latex particles. So the presence of the clay in nylon 6 matrix does not disturb the latex particles to promote high fracture toughness via particle cavitation and subsequent matrix shear yielding, and therefore, provides maximum reinforcement to the polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011