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991.
填充母料及其他常用塑料母料   总被引:1,自引:0,他引:1  
塑料母料对推动塑料工业的迅猛发展起了很大作用,其主要特点是:可以简化生产工艺过程:原料混合方便,混炼质量均匀,提高生产效率及制品性能指标;减少粉尘飞扬及对设备的磨损;降低制品在换色时清洗螺杆的用料量;延长原料储存的保质期等。  相似文献   
992.
This paper studies the Voronoi diagrams on 2‐manifold meshes based on geodesic metric (a.k.a. geodesic Voronoi diagrams or GVDs), which have polyline generators. We show that our general setting leads to situations more complicated than conventional 2D Euclidean Voronoi diagrams as well as point‐source based GVDs, since a typical bisector contains line segments, hyperbolic segments and parabolic segments. To tackle this challenge, we introduce a new concept, called local Voronoi diagram (LVD), which is a combination of additively weighted Voronoi diagram and line‐segment Voronoi diagram on a mesh triangle. We show that when restricting on a single mesh triangle, the GVD is a subset of the LVD and only two types of mesh triangles can contain GVD edges. Based on these results, we propose an efficient algorithm for constructing the GVD with polyline generators. Our algorithm runs in O(nNlogN) time and takes O(nN) space on an n‐face mesh with m generators, where N = max{m, n}. Computational results on real‐world models demonstrate the efficiency of our algorithm.  相似文献   
993.
对胺烷基化聚羟基酸酰胺的合成方法进行研究,确立了反应条件与制得的聚羟基酸酯特征之间的一些相互关系。并为获得适当长度的聚酯链选择了最佳合成条件。同时扼要论述了这类超分散剂的结构特性,以及对于颜料粒子表面吸附作用、分散体系的稳定作用以及对涂料、油墨生产的重要意义。  相似文献   
994.
固体酸SO4(2-)/Nb2O5催化合成尼龙酸二异丁酯   总被引:6,自引:0,他引:6  
研究了SO4^2-/Nb2O5作为催化剂催化合成尼龙酸二异丁酯的反应。通过正交试验确定了最佳反应条件:酸醇物质的量比为1:2.5,催化剂为反应物总量的0.35%,反应回流2.0h,在此条件下酯化率可达97.8%。  相似文献   
995.
This paper presents a novel method that uses the interception effect of gradient magnetic field on oxygen molecules to realize enrichment. The use of two opposite magnetic poles of two magnets at a certain distance forms a magnetic space having a field intensity gradient near its borders. When air injected into the magnetic space outflows from the magnetic space via its borders, oxygen molecules in the air will experience the interception effect of the gradient magnetic field, but nitrogen molecules will outflow from the magnetic space without hindrance. Thus, continuous oxygen enrichment is realized. The enrichment degree of oxygen reaches 0.65% when the inlet and outlet air flows are 40 mL/min and 20 mL/min, respectively, and the gas temperature is 298 K and the maximal product of magnetic flux density and its gradient is 563 T2/m (the distance between two magnetic poles is 1 mm). When the gas temperature rises to 343 K, the enrichment degree drops to 0.32%; and when the maximal product of magnetic flux density and field intensity gradient drops to 101 T2/m (the distance between two magnetic poles is 4 mm), the enrichment degree drops to 0.23%. The experimental results show that there is an optimal ratio between the inlet air flow and the outlet air flow. Under the experimental conditions in this paper, the value is about 2.0. It is demonstrated that the method presented in this paper can continuously enrich oxygen and has a higher enrichment degree than other oxygen-enrichment methods using magnetic separation. Translated from Journal of Beijing University of Chemical Technology, 2006, 33(5): 62–66 [译自: 北京化工大学学报]  相似文献   
996.
Xuping Sun 《Polymer》2004,45(7):2181-2184
Polyelectrolyte-protected gold nanoparticles have been facilely obtained by heating an amine-containing polyelectrolyte/HAuCl4 aqueous solution without the additional step of introducing other reducing agents. All experimental data indicate that different initial molar ratio of polyelectrolyte to gold can lead to the formation of dispersed nanoparticles, quasi one-dimensional aggregates of nanoparticles or bulk metal deposits. More importantly, the growth kinetics of gold particles thus formed can be tuned by changing the initial molar ratio of polyelectrolyte to gold.  相似文献   
997.
国外陶瓷球加工技术及其应用   总被引:4,自引:0,他引:4  
孙永安  李县辉 《陶瓷学报》2002,23(2):145-148
主要综述了国外陶瓷球的加工技术,加工陶瓷球使用的设备,研磨介质和研磨料的选择,介绍了陶瓷球及陶瓷球轴承的应用发展概况。  相似文献   
998.
The chemical equilibrium for the coupling of ethylbenzene dehydrogenation with nitrobenzene hydrogenation, to produce styrene and aniline simultaneously, has been calculated on the basis of the Soave–Redlich–Kwong equation of state. The dehydrogenation of ethylbenzene in the presence of nitrobenzene over the catalysts -Al2O3, ZSM-5, activated carbon and platinum supported on activated carbon has been carried out at 400 °C. The effects of Pt loading and the pretreatment of the catalysts have been investigated. It has been revealed that the conversion of ethylbenzene can be greatly improved by the reaction coupling due to the elimination of the hydrogen produced in the reaction by the hydrogenation of nitrobenzene. Platinum supported on the activated carbon has been suggested as a suitable catalyst. The best results with ethylbenzene conversion of 33.8% and styrene selectivity of 99.2% were obtained over Pt(0.02 wt%)/AC at 400 °C. Moreover, such process is also energetically favored since the necessary process heat to drive the ethylbenzene dehydrogenation can be provided by the coupling with the exothermic nitrobenzene hydrogenation reaction.  相似文献   
999.
Hua Yang  Zhong-yuan Lu  Chia-chung Sun 《Polymer》2004,45(19):6753-6759
By means of the molecular dynamics (MD) simulation, the crystallization mechanism of 22,8-polyurethane which contains hydrogen-bond units is investigated and the results show that the crystallization process at a fixed temperature can be characterized by three stages: (1) The extended chain collapses to a globular random coil; (2) The random coil reorganizes into an ordered lamellar structure; (3) Accompanied with the segments clustering due to the hydrogen-bond formation, the lamellar develops with local defects. Two kinds of hydrogen-bond, which are formed between NH group and CO group (N-H?OC), and between NH group and urethane alkoxy oxygen (N-H?O), respectively, are found to play an important role in the crystallization process of 22,8-polyurethane. Furthermore, the effect of temperature on the crystallization is also studied by selecting three temperatures 200, 300 and 400 K. The lower the crystal temperature is, the slower the crystallization rate is and the stronger the hydrogen-bonding interactions are presented. This is in harmony with the experimental results.  相似文献   
1000.
在线分析仪表水封结构的改进   总被引:1,自引:0,他引:1  
熊延英  孙斌  刘梦梅 《化肥工业》2007,34(3):41-42,45
原在线分析仪表的水封工作时,存在样气串气、带尘、带液现象,造成在线分析仪器的腐蚀并影响仪表指示,致使分析结果不准确或出现故障。水封结构改进后,在线分析系统的稳定性、可靠性大为提高。  相似文献   
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