房产交易与信息发布系统的开发及实现

综合考虑了一般房产管理的运行模式和现有的网络地理信息系统实现方法,在探索一个性能价格比高的房产交易与信息发布系统的实现方法的基础上,提出了一种基于Internet或Intranet上的房产交易管理信息系统模型模式;采用网络的主流技术ASP,同时结合ESRI公司的ArcIMS用SQLSERVER2000数据库实现房产交易管理和房产信息发布。     

Classification using proximity catch digraphs

Machine Learning - We employ random geometric digraphs to construct semi-parametric classifiers. These data-random digraphs belong to parameterized random digraph families called proximity catch...     

Compression molding and melt‐spinning of the blends of poly(lactic acid) and poly(butylene succinate‐co‐adipate)

Poly(lactic acid) (PLA) is a biobased polymer made from biomass having high mechanical properties for engineering materials applications. However, PLA has certain limited properties such as its brittleness and low heat distortion temperature. Thus, the aim of this study is to improve toughness of PLA by blending with poly(butylene succinate‐co‐adipate) (PBSA), the biodegradable polymer having high toughness. Polymer blends of PLA and PBSA were prepared using a twin screw extruder. The melt rheology and the thermal property of the blends were examined. Further the blends were fabricated into compression molded parts and melt‐spun fiber and were subjected to tensile and impact tests. When the PBSA content was low, PBSA phase was finely dispersed in the PLA matrix. On the other hand, when the PBSA content was high, this minor phase dispersed as a large droplet. Mechanical properties of the compression molded parts were affected by the dispersion state of PBSA minor component in PLA matrix. Impact strength of the compression molded parts was also improved by the addition of soft PBSA. The improvement was pronounced when the PBSA phase was finely dispersed in PLA matrix. However, the mechanical property of the blend fibers was affected by the postdrawing condition as well as the PBSA content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41856.     

Erosion, corrosion and erosion–corrosion of EB PVD thermal barrier coatings

Electron beam (EB) physical vapour deposited (PVD) thermal barrier coatings (TBCs) have been used in gas turbine engines for a number of years. The primary mode of failure is attributed to oxidation of the bond coat and growth of the thermally grown oxide (TGO), the alumina scale that forms on the bond coat and to which the ceramic top coat adheres. Once the TGO reaches a critical thickness, the TBC tends to spall and expose the underlying substrate to the hot gases. Erosion is commonly accepted as a secondary failure mechanism, which thins the TBC thus reducing its insulation capability and increasing the TGO growth rate. In severe conditions, erosion can completely remove the TBC over time, again resulting in the exposure of the substrate, typically Ni-based superalloys. Since engine efficiency is related to turbine entry temperature (TET), there is a constant driving force to increase this temperature. With this drive for higher TETs comes corrosion problems for the yttria stabilised zirconia (YSZ) ceramic topcoat. YSZ is susceptible to attack from molten calcium–magnesium–alumina–silicates (CMAS) which degrades the YSZ both chemically and micro-structurally. CMAS has a melting point of around 1240 °C and since it is common in atmospheric dust it is easily deposited onto gas turbine blades. If the CMAS then melts and penetrates into the ceramic, the life of the TBC can be significantly reduced. This paper discusses the various failure mechanisms associated with the erosion, corrosion and erosion–corrosion of EB PVD TBCs. The concept of a dimensionless ratio D/d, where D is the contact footprint diameter and d is the column diameter, as a means of determining the erosion mechanism is introduced and discussed for EB PVD TBCs.     

Experimental study of pressurized gas-fluidized bed heat transfer

This paper reports on an experimental study of the influence of operating pressure, in the range 150-1100 kPa, on wall-to-bed heat transfer coefficient in a bubbling fluidized bed. Both Geldart Group A and B solids were studied and the fluidizing gases were air and superheated steam. Fluidizing velocities were in the range 1-33 U_mf and wall temperatures in the range 125-275°C. Wall-to-bed heat transfer coefficients were found to increase steadily with increasing fluidizing gas velocity and not to pass through a maximum. Increase in operating pressure was found generally to result in an increase in wall-to-bed heat transfer coefficient, although the effect is probably non-linear. In the bubbling regime, the wall-to-bed heat transfer coefficient was found to change with vertical position in the bed. Wall-to-bed heat transfer coefficients decreased when the bed entered the slugging regime.     

Oxidation Behaviour of NiCrAl and NiCoCrAl Bond Coatings Under Industrial Gas Turbine Conditions

Model bond coatings were deposited with a wide range of compositions and their oxidation behaviour investigated at 900 °C. These Ni–Co–Cr–Al coatings were deposited using magnetron sputtering (a physical vapour deposition technique) onto 10 mm diameter sapphire substrates. A range of compositions was generated by co-sputtering from a combination of two or three sources: Ni–10 wt% Cr, Ni–20Cr, Ni–50Cr, Ni–20Co–40Cr and/or Ni–40Co–20Cr combined with pure Al. The coatings were oxidised at 900 °C and the scales formed characterised. These data have been summarised into oxide predominance diagrams to show the relationships between coating compositions and the formation of protective Cr₂O₃ or Al₂O₃ scales, or the formation of other, less protective oxides (or mixed oxides). Both coating composition and exposure temperature (by comparison with earlier published research) were found to influence the oxide scale growth rate and oxide type, and thus the resulting degree of protection.