Nonisothermal melt-crystallization kinetics of isotactic polypropylene synthesized with a metallocene catalyst and compounded with different quantities of an α nucleator

The nonisothermal crystallization kinetics of a metallocene-made isotactic polypropylene (m-iPP) and its compounds with 0.1 wt % and 0.3 wt % of a sorbitol derivative [1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol (DMDBS); an α nucleator] were investigated by differential scanning calorimetry at different cooling rates from the melt. The nucleation efficiency was proved by a significant increase in the crystallization temperatures (accompanied by a slight augmentation of the degree of crystallinity and a decrease in the crystal sizes). This increase in the crystallization temperatures led to higher amounts of fractional content in the γ polymorph, even though DMDBS was supposed to be a nucleator for the α form. The Avrami and Ozawa methods effectively described only the early stage of crystallization, whereas a combined Avrami–Ozawa method was valid for the whole crystallization process. The values of the exponent for this method decreased for nucleated samples in the later stage of crystallization, especially in the case of m-iPP with 0.3 wt % DMDBS added (m-iPP03). The activation energy of the process and the surface free energy were also estimated. The production of considerable proportions of the γ polymorph in m-iPP03 corresponded to higher values of the activation energy and lower values of the surface free energy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

长输管线变电所备用电源自动投入系统的改造

根据管道储运公司下属的各变电所目前的运行方式以及备用电源自动投入系统(以下简称“备自投”)的运行情况，指出了备自投使用中的不足之处，并通过增加对应断路器的辅助触点来完善备自投，使变电所运行更加可靠。     

Repetition Blindness Occurs in Nonwords.

Theorists have predicted that repetition blindness (RB) should be absent for nonwords because they do not activate preexisting mental types. The authors hypothesized that RB would be observed for nonwords because RB can occur at a sublexical level. Four experiments showed that RB is observed for word-nonword pairs (noon noof), orthographically similar nonwords (glome glame), and identical repetitions (plass plass). More RB was found for words than for nonwords. Prior researchers may have failed to find RB for nonwords because display conditions that allow 2 words to be reliably encoded are insufficient for nonwords, or because observers coped with low ability to encode nonwords by using guessing strategies that do not require creating a mental type or tokenizing it. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Creep Crack Growth in Polypropylene Film with Various Crack Lengths at Diverse Stresses and Temperatures

Creep crack growth rates were measured using centrally cracked tension specimens of thin polypropylene film with different crack lengths at various stresses and temperatures. The creep crack growth rates were correlated with the stress intensity factor. There was the region of the minimum constant crack growth rate which occupied more than 70% of the total creep failure life. This constant creep crack growth rate characteristics were analyzed on the basis of the stress-dependent Arrhenius type thermally activated process.     

高炉喷吹废塑料燃烧动力学研究

为了提供高炉喷吹废塑料新技术工业化应用的理论依据，通过对其动力学参数的求解，研究了高炉喷吹废塑料的燃烧动力学，得出了该燃烧反应是一级反应，且在温度为200℃、塑料配比为20％～25％时活化能最低、燃烧阻力小的结论。     

Automatic processing of psychological distance: Evidence from a Stroop task.

A picture-word version of the Stroop task was used to test the automatic activation of psychological distance by words carrying various senses of psychological distance: temporal (tomorrow, in a year), social (friend, enemy), and hypotheticality (sure, maybe). The pictures implied depth, with the words appearing relatively close to or distant from the observer. The participants classified the spatial distance of words faster when the word's implicit psychological distance matched its spatial distance (e.g., a geographically close word was classified faster when it was "friend" than when it was "enemy"). The findings are consistent with the idea that psychological distance is accessed automatically, even when it is not directly related to people's current goals, and suggest that psychological distance is an important dimension of meaning, common to spatial distance, temporal distance, social distance, and hypotheticality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Propane conversion over zeolite catalysts: Comments on the role of Ga

The activation of propane using zeolite H-Y and Ga³⁺ exchanged zeolite Y indicates that in the presence of Ga³⁺ the mechanism of propane activation is changed from a cracking pathway to a dehydrogenation pathway. The presence of both Ga³⁺ and H⁺ are required to achieve this effect.     

Electrical and optical properties of MoO3-V2O5 mixed oxide films

Vacuum deposited MoO₃-V₂O₅ films of different molar concentrations have been used for DC electrical conductivity studies at different temperatures. The optical absorption spectra of MoO₃-V₂O₅ films of different molar concentrations have been measured. From these measurements it is found that optical band gap and activation energy vary with molar concentration of MoO₃-V₂O₅ films.     

Structural and electrical measurements of CdZnSe composite

TheI—Vcharacterization and the electrical resistivity of selenium rich Se₈₅Cd_15-xZn_x (x = 0, 3, 7, 11 and 15) system at room temperature have been studied. Samples were obtained using melt cooling technique. So prepared samples were then characterized in terms of their crystal structure and lattice parameter using X-ray diffraction method. The materials were found to be poly crystalline in nature, having zinc blend structure over the whole range of zinc concentration. The measurements ofI—V bdcharacteristics have been carried out at different temperatures from room to 140°C. The electrical resistivity of the samples with composition at room temperature has been found to vary between maximum 2.7 x 10⁸ Ωm and minimum 7.3 x 10⁵ Ωm and shows a maximum at 3 at. wt.% of Zn. The carrier activation energy of the samples with composition has also been determined and found to vary from 0.026 eV to 0.111 eV.     

石灰石分解反应的热重动力学研究

用热重分析等研究方法，对我国９个主要产地的石灰石矿样品进行了大量的实验和分析工作，并分别计算出不同产地石灰石的动力学数据。