低雾化低挥发性汽车用新型聚氨酯泡沫塑料助剂

康普顿公司开发了一系列适用于消除或减少汽车内饰件中胺扩散或雾化的添加剂，其中包括快速、有效的生产用零扩散催化剂和低雾化表面活性剂。该系列添加剂能大大降低泡沫制品中的胺扩散，与异氰酸酯和多元醇原料能组成最佳组合，以保持良好的泡沫物理性能。     

The allelopathic mechanisms of dominance in bracken (Pteridium aquilinum) in Southern California

Bracken,Pteridium aquilinum, exerts a strong dominance over associated plants throughout much of its worldwide range. Associated plants are often severely inhibited or even excluded from dense stands of the fern. This study investigated the various aspects of herb suppression in bracken stands and assessed the contribution of the various forms of interference between plants to the establishment and maintenance of bracken dominance. It was shown that competition for soil moisture, light, and nutrients could not account for the lack of herbs in bracken stands. Further, uniformity of soil pH, texture, water-holding capacity, and organic matter content ruled out variability in physical factors as a cause. Baiting and trapping experiments showed that the higher concentration of animal activity inside the bracken stands contributed significantly to the pattern of herb suppression, but only against select species. The maintenance of this pattern in the animal-free Santa Cruz Island stands indicates the importance of another factor, allelopathy. It was found that phytotoxins leached from the dead, standing bracken fronds with the first few rains of the wet season were largely responsible for herb suppression. These toxins were isolated in raindrip and from soil inside the fern stands. Removal of the fronds from the stand before the rains could leach them resulted in reinvasion by the herbs after several seasons, and, conversely, placing fronds over the herbs in the grassland brought about herb inhibition. A number of known allelopathic chemicals were tentatively identified from bracken leachates. The importance of the interaction of allelopathy with other factors of plant interference is illustrated by bracken.     

工程机械轮胎成型机的发展

缓慢,因为人们关注的主要是生产大宗轮胎的机器。因此,新一代工程机械轮胎成型机的出现具有特殊的意义,特别是因为这种轮胎的市场条件正在迅速变化。目前,大部分工程机械轮胎成型机都相当陈旧,对它们往往是进行修理和改造,而不是更新。工程机械轮胎成型的理念和技术相当长时间以来未发生变化,这意味着大胎生产往往需要大量手工劳动。近年来唯一真正的改进是采用轮胎胎面胶条自动缠绕工艺。不愿更新工程机械轮胎成型机的一个历史原因可能是投资比较大,它与这一市场用量较低相矛盾。但是目前工程机械轮胎的发展(供选择轮胎越来越多,批量越来越…     

Study of hemocompatibility and endothelial cell interaction of tecoflex-based electrospun vascular grafts

Abstract

Ensuring long-term functioning and efficient endothelialization of small diameter vascular grafts (VG) is an urgent task of tissue engineering. A solution may be to use electrospun VGs prepared from blends polyurethane with gelatin and/or bivalirudin. Here, properties of 3D matrices were explored by SEM, contact angle measurements and IR spectroscopy, and their interaction with blood and endothelial cells was studied. Introduction of gelatin into matrices enhanced adhesion and proliferation of endotheliocytes and enabled adhesion of platelets, whereas bivalirudin inhibited platelet adhesion while having no negative effect on the adhesion and proliferation of endothelial cells.     

Online light scattering measurements: A method to assess morphology development of polymer blends in a twin‐screw extruder

Light scattering has proved itself an efficient technique to determine particle diameters in heterogeneous dilute dispersions in the micrometer range. Extrusion of polymer blends is expected to give rise to very small particles, typically in the range from hundreds of nanometers to tens of micrometers. A light scattering device developed in our laboratory has been used to study the morphology of polymer blends obtained in a twin‐screw extruder. The main advantage of this technique is the immediate response obtained without any surface or interface modification that can occur during the sample preparation by using more conventional techniques like electron microscopy. To show the possible applications of this light scattering device, preliminary tests have been carried out. First, we present a comparison between experimental measurements and theoretical results for dilute systems. Second, we have investigated the effect of shear flow on the droplet deformation. Finally, we have studied the variations of the light scattering pattern for a reactive blend.     

Low-temperature phase formation in the SrF2–LaF3 system

Phase formation in the SrF₂–LaF₃ system was studied at temperatures ranging from 300°C to 450°C using nitrate flux. The solubility of LaF₃ in SrF₂ decreases with decreasing temperature. The equilibrium width of the solid solution region Sr_1−xLa_xF_2+x at 400°C, it is 44.6 ± 0.4 mol% LaF₃ (x = 0.446), at 350°C — 38.3 ± 0.7 mol% LaF₃ (x = 0.383), and decreases almost to zero at 300°C.     

Result Merging Technique for Answering XPath Query over XSLT Transformed Data

Caching stores the results of previously answered queries in order to answer succeeding queries faster by reusing these results. We propose two different approaches for using caches of XSLT transformed XML data in order to answer queries. The first approach checks whether or not a current query Q can be directly answered from the result of a previously answered query Qi stored in the cache. The new query is otherwise submitted to the source over the network, the answer of the query is determined, transmitted back to the client, and stored in the cache. The second approach determines only the intersection Q−Qi and integrates the result of Q−-Qi into the previous results in the cache, which requires applying a numbering scheme for the output of the XSLT stylesheet. We show by experimental results that the second approach can significantly speed up the answering time in comparison to the first approach, but is not significantly slower in few worst cases than the second approach.     

A cost-effective lexical acquisition process for large-scale thesaurus translation

Thesauri and controlled vocabularies facilitate access to digital collections by explicitly representing the underlying principles of organization. Translation of such resources into multiple languages is an important component for providing multilingual access. However, the specificity of vocabulary terms in most thesauri precludes fully-automatic translation using general-domain lexical resources. In this paper, we present an efficient process for leveraging human translations to construct domain-specific lexical resources. This process is illustrated on a thesaurus of 56,000 concepts used to catalog a large archive of oral histories. We elicited human translations on a small subset of concepts, induced a probabilistic phrase dictionary from these translations, and used the resulting resource to automatically translate the rest of the thesaurus. Two separate evaluations demonstrate the acceptability of the automatic translations and the cost-effectiveness of our approach.

Influence of grain boundary weak links on the nonequilibrium response of YBaCuO thin films to short laser pulses

The transient voltage response in both epitaxial and granular YBaCuO thin films to 80 ps pulses of YAGNd laser radiation of wavelength 0.63 and 1.54 m was studied. In the normal and resistive states both types of films demonstrate two components: a nonequilibrium picosecond component and a bolometric nanosecond one. The normalized amplitudes are almost the same for all films. In the superconducting state we observed a kinetic inductive response and two-component shape after integration. The normalized amplitude of the response in granular films is up to five orders of magnitude larger than in epitaxial films. We interpret the nonequilibrium response in terms of a suppression of the order parameter by the excess of quasiparticles followed by the change of resistance in the normal and resistive states or kinetic inductance in the superconducting state. The sharp rise of inductive response in granular films is explained both by a diminishing of the cross section for current percolation through the disordered network of Josephson weak links and by a decrease of condensate density in neighboring regions.