N1-(2-苯基-1,2,3-三唑-4-甲酰基)-吡唑类衍生物的合成

利用２－苯基－１,２,３－三唑－４－甲酰肼（１）分别与３－芳基偶氮乙酰丙酮（２）和３－芳基偶氮乙酰乙酸乙酯（３）在酸性条件下环化,制得１２个新的Ｎ１－（２－苯基－１,２,３－三唑－４－甲酰基（－３,５－二甲基－４－芳基偶氮吡唑（４）和Ｎ１－（２－苯革－１,２,３－三唑－４－甲酰基）－３－甲基－４－芳基偶氮－２－吡唑啉－５－酮（５）,用元素分析、ＩＲ、＾１ＨＮＭＲ和ＭＳ确定了它们的结构。     

Deposition of Nano-Size Titania—Silica Particles in a Hot-Wall CVD Process

The deposition of nano-size titania—silica particles is carried out in a hot-wall CVD reactor by using two premixed precursors, titanium tetraisopropoxide (TTIP) and tetraethyl orthosilicate (TEOS). The deposition occurs mostly in two regions, one near the reactor entrance and the other near the reactor exit. Deposits collected near the reactor entrance are densely packed micrometer-size aggregates/particles of good adhesion to the substrate, while those near the reactor exit are loosely packed nano-size particles with a poor adhesion to the substrate. It is conjectured that the more reactive TTIP reacts first and produces TiO₂ particles later covered by SiO₂ formed via a catalytic surface reaction of the less reactive TEOS on TiO₂ particle surfaces. The presence of surface SiO₂ retards the growth of TiO₂ particles, leading to deposits formed by micrometer-size aggregates containing nano-size primary particles of 30 to 40 nm in the first deposition region. With less or no SiO₂ present on TiO₂ particle surfaces, the deposits formed in the first deposition region are densely packed micrometer-size particles. The Ti/Si ratio of the produced particles, for a furnace temperature of 750°C, increases with increasing TTIP/TEOS concentration ratio, and is lower than the Ti/Si ratio of the incoming reactant stream. The Ti/Si ratio of the particles is also found to decrease with increasing furnace temperature.     

Colloid Emulsion of Nanosized Strontium Bismuth Tantalate Powder

A novel colloid-emulsion process has been used to synthesize nanosized strontium bismuth tantalate (SrBi₂Ta₂O₉) particles. During calcination, the desired bismuth-layered structure phase develops at the expense of the pyrochlore phase. Calcining the precursor powder at 750°C for 2 h leads to the complete formation of single-phase layered-structured SrBi₂Ta₂O₉. The powder that is formed consists of nanoparticles with a narrow size distribution and almost-spherical morphology. The crystallinity of the calcined powder increases as the calcination temperature and heating time increases. The developed colloid-emulsion process significantly reduces the SrBi₂Ta₂O₉ particle size, in comparison to conventional process techniques, and results in a uniform microstructure of the obtained powder.     

新世纪全球香料工业展望

分析了全球香料行业的现状和未来的发展趋势,结合我国香料行业的发展现状,探讨了我国香料行业在新的世纪面临的机遇和挑战,并对我国香料工业今后的发展提出了自己的建议。     

高原缺氧环境下立窑用风量的计算

１　立窑煅烧用风量的计算方法１．１　标准状况下煤燃烧所需理论空气量 当已知煤的应用基组成时,标准状况下燃烧所需理论空气量计算公式为：也可用近似计算公式：式中：──标准状况下煤燃烧所需理论空气量, ──烧成用煤的低位应用基热值, ｋＪ／ｋｇ。１．２　标准状况下煤燃烧所需实际空气量 实际生产中为了防止发生燃料不完全燃烧现象,考虑适当的过剩空气。即实际空气量： 式中：Ｖａ──标准状况下煤燃烧所需实际空气量, ｍ３ ／ｋｇ; α──空气过剩系数．１．１～１．３,机立窑可取 １．２。１．３　常温状态下煤燃烧所需实…     

Kinetics of Thermal Dehydroxylation and Carbonation of Magnesium Hydroxide

The kinetics of simultaneous dehydroxylation and carbonation of precipitated Mg(OH)₂ were studied using isothermal and nonisothermal thermogravimetric analyses. Specimens were analyzed using X-ray diffraction, transmission electron microscopy, and through measurements of the volume of carbon dioxide evolved in a subsequent reaction with hydrochloric acid. From 275° to 475°C, the kinetics of isothermal dehydroxylation in helium were best fit to a contracting-sphere model, yielding an activation energy of 146 kJ/mol, which was greater than values reported in the literature for isothermal dehydroxylation under vacuum (53–126 kJ/mol). The carbonation kinetics were complicated by the fact that dehydroxylation occurred simultaneously. The overall kinetics also could be fit to a contracting-sphere model, yielding a net activation energy of 304 kJ/mol. The most rapid carbonation kinetics occurred near 375°C. At this temperature, Mg(OH)₂ underwent rapid dehydroxylation and subsequent phase transformation, whereas thermodynamics favored the formation of carbonate. During carbonation, MgCO₃ precipitated on the surface of disrupted Mg(OH)₂ crystals acting as a kinetic barrier to both the outward diffusion of H₂O and the inward diffusion of CO₂.     

Fracture toughness characterization of a PC/ABS blend under different strain rates by various J-integral methods

A published, nonconventional J-integral method, based on the hysteresis energy and the ASTM E813 methods, has been employed to test the fracture toughness of a polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) blend. The critical J values (J_Ic) at crosshead speeds ranging from 0.5 to 20 mm/min obtained from the hysteresis energy method are ∼10 to 20% higher than those obtained from the E813–81 method and ∼50 to 70% lower than those obtained from the E813–87 method. However, the hysteresis energy method results in comparable J_Ic values with a modified ASTM E813–87 method when the 0.2 mm offset line is replaced with a 0.1 mm offset line. The critical displacements in terms of the onset of crack initiation, determined from the plots of hysteresis energy vs. displacement, hysteresis ratio vs. displacement, and the true crack growth length vs. displacement, are fairly close in value. This indicates the critical crack initiation and the corresponding J_Ic obtained from this hysteresis energy method indeed represent the actual physical event of the onset of crack initiation.     

含铝硝胺推进剂配方优化设计

利用正交设计方法对含铝硝胺推进剂配方进行了优化设计，并结合工艺性能确定出优选的推进剂配方。     

白细胞介素-2脂质体药物动力学的研究

~(125)I-IL－2脂质体及游离~(125)I-IL－2通过小鼠尾静脉给药后，观察其在主要脏器中的药物分布及血药浓度-时间曲线。结果表明，脾脏和肝脏对IL－2脂质体有较高的摄取，IL－2脂质体具有缓释作用；IL－2脂质体的血浆清除率明显低于单纯IL－2，其生物利用度明显提高。     

Toughening of nylon 6 with core-shell impact modifiers: Effect of matrix molecular weight

Rubber particle size is an important issue in toughening of engineering thermoplastics. Use of core-shell impact modifiers offers the advantage of a predetermined particle size; however, these particles must be appropriately dispersed in the matrix polymer to be effective for toughening. Recent work has shown that core-shell modifiers having a poly(methyl methacrylate) (PMMA) shell can be dispersed in nylon 6 with the aid of certain styrene/maleic anhydride (SMA) copolymers. These materials are miscible with PMMA and can also react with polyamides during melt processing. Enhanced interaction between the rubber and matrix phases as a result of the formation of in situ graft copolymers at the interface was suggested to contribute to the improved dispersion. However, rheological issues also influence the dispersion of core-shell modifier particles in the matrix. This article examines the influence of the matrix melt viscosity on the dispersion of the core-shell particles in the nylon 6 matrix and the resulting mechanical properties of the blends using four nylon 6 materials of different molecular weights. © 1996 John Wiley & Sons, Inc.