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991.
992.
对W Z-C系列无料钟高炉炉顶布料设备上、下密封阀在涟钢3#高炉的使用情况进行了论述,分析了故障产生的机理,对密封阀的结构进行了改造并取得了相当可观的经济效益。 相似文献
993.
Xiaodan Zhang Wei Liu Dale Sun Youguo Li 《Metallurgical and Materials Transactions A》2007,38(3):499-505
The transformation of carbides with austenization time of a high speed steel (HSS) roll material, manufactured by a centrifugal
casting method, has been studied. The correlation between wear resistance and the type, morphology, volume fraction, and distribution
of the carbides has also been investigated. Microstructural observations, X-ray diffraction (XRD) analysis, hardness measurements,
and energy dispersive spectroscopy (EDS) have been used to characterize the carbides. The type and volume fraction of carbides
were found to change with austenizing time. During austenization, the transformation of the M3C carbides can be postulated as M3C + γ-Fe → M2C, with much finer nodular and rodlike MC carbides also forming through a solid-state transformation. The M2C carbide decomposes as M2C + γ-Fe → MC + M7C3 + M6C. The decomposed carbide substantially maintains a platelike shape until the end of decomposition. The most important finding
of this study is that austenization results in changes in the type, morphology, volume fraction, and distribution of carbides
and that it can be controlled to produced a homogeneous distribution of hard carbides, resulting in an improvement in the
wear resistance of HSS rolls. This finding may be of great use for the industrial production of HSS rolls. 相似文献
994.
Following the original model for a single cell/dendrite growth by Hunt,[5] systematic numerical simulations are carried out with focus on cell shape evolution and tip radius selection in a directional
solidification process conducted in a capillary tube. Computations indicate that the anisotropy of solid/liquid interfacial
energy and the diameter of a capillary tube have significant influences on the selection of a tip shape. The anisotropy in
dilute SCN-salol alloys has been determined through the equilibrium droplet shape method and its value is 1.09 pct. The calculated
cell/dendrite shapes with this value of anisotropy agree with experimental observations where a single cell/dendrite of SCN-salol
alloys grows in a capillary tube. 相似文献
995.
In the design of algorithms for large-scale applications it is essential to consider the problem of minimizing I/O communication.
Geographical information systems (GIS) are good examples of such large-scale applications as they frequently handle huge amounts
of spatial data. In this paper we develop efficient external-memory algorithms for a number of important problems involving
line segments in the plane, including trapezoid decomposition, batched planar point location, triangulation, red--blue line
segment intersection reporting, and general line segment intersection reporting. In GIS systems the first three problems are
useful for rendering and modeling, and the latter two are frequently used for overlaying maps and extracting information from
them. 相似文献
996.
Confluent graphs capture the connection properties of train tracks, offering a very natural generalization of planar graphs,
and—as the example of railroad maps shows—are an important tool in graph visualization. In this paper we continue the study
of confluent graphs, introducing strongly confluent graphs and tree-confluent graphs. We show that strongly confluent graphs
can be recognized in NP (the complexity of recognizing confluent graphs remains open). We also give a natural elimination
ordering characterization of tree-confluent graphs, and we show that this class coincides with the (6,2)-chordal bipartite
graphs. Finally, we define outerconfluent graphs and identify the bipartite permutation graphs as a natural subclass. 相似文献
997.
刘品意 《消防技术与产品信息》2005,(2):12-14
通过对西部某小城市的住宅消防设施建设和管理现状的调查 ,反映了占西部绝大部分城市面积的中小城镇的住宅消防设施十分令人担忧的现状 ,分析了造成这一现状的原因 ,提出了解决这一问题的建设管理思路 相似文献
998.
公共关系是提高企业形象竞争力的法宝,企业将公共关系运用于营销活动之中,能够与社会公众建立、维持和发展良好的互利关系,通过树立良好的企业形象和信誉,从而为企业市场营销创造一个和谐的环境。从公共关系与市场营销的内涵入手,对市场营销中公共关系的作用和具体应用进行了初步的分析,希望通过这些分析,能够引起陶瓷企业在营销活动中对公共关系的注意。 相似文献
999.
Jianying Li Shengtao Li Fuyi Liu M. A. Alim 《Journal of Materials Science: Materials in Electronics》2006,17(3):211-217
The post-sintering heat treatment on the current-voltage behavior of the ZnO-Bi2O3 based varistors is reported. It is suggested that only phase transition of the Bi2O3 is not alone responsible for the resulting electrical performance by these devices. The ambient condition influences the
performance parameters. Thus, incorporating the role of oxygen and zinc interstitial in the total device during the post-sintering
heat-treatment is accounted as responsible parameters for the ultimate performance. Two recipes are used in demonstrating
the effect of heat-treatment on the functional behavior of the devices. 相似文献
1000.