总承包工程中设计阶段的造价控制

工程建设造价控制的重点在设计阶段,设计阶段造价控制的特点、方法及思考.     

Electrochemical formation of poly(thionine) thin films: The effect of amine group on the polymeric film formation of phenothiazine dyes

The electropolymerization of thionine in an aqueous solution has been carried out by using both cycling voltammetry and chronoamperometry experiments. Electropolymerization has been applied at various pHs by using different working electrodes. The characterization of poly(thionine) thin films is performed by using cyclic voltammetry, current–time transients, atomic force microscopy, scanning tunnelling microscopy, ATR‐FTIR, and UV–vis absorption spectroscopy techniques. It is deduced from current–time transients and morphological data that poly(thionine) film forms with random adsorption process and exhibits an irregular polymeric film. Poly(thionine) film formation was compared with that of previously published results of phenothiazine derivatives of poly(azure A) and poly(methylene blue). It has been concluded that type of amine functional group of phenothiazine dyes is very effective on the formation of polymeric film structure. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39686.     

Ozonation of Reactive Orange 122 Using La3+-Doped WO3/TiO2/Sep Photocatalyst

La³⁺/WO₃/TiO₂/sep composites have been prepared by the sol–gel method. The degradation of dye was studied under the influence of various operational parameters such as initial pH, amounts of catalyst, concentrations of the dye, and ozone flow rate. The mineralization of Reactive Orange 122 has been confirmed by chemical oxygen demand measurements. The color removal of dye was found to follow a pseudo–first-order kinetics. Maximum color and chemical oxygen demand removal were 99.9% and 90% respectively, at a dye concentration of 200 mg/L, ozone flow rate of 2.0 L/min., 0.05 g/L weight of catalyst, and pH of 6.9 in 4 h. In addition, the catalyst was characterized by X-ray diffraction spectra, Fourier-Transform Infrared Spectroscopy, scanning electron microscopy, and a transmission electron microscope. This work could be a good candidate as a practical application for photocatalytic dye degradation.     

铁电薄膜材料及集成铁电器件的相关问题

铁电薄膜材料及集成铁电器件自20世纪90年代以来一直受到人们的关注，就目前该领域研究中的几个基础问题，如生长动力学、特性退变、异质结界面以及如何进一步发展铁电薄膜和集成铁电器件等提出了见解。     

球铁初生A体枝晶生长的计算机模拟

用Ｌ系统分形法，模拟了亚共晶球墨铸铁初生Ａ体的形态及其生长，并实现了微观组织的计算机模拟图象显示，模拟结果符合亚共晶球铁的一次结晶过程；Ａ体枝晶的三种形态及其生长具有模拟性；Ａ体生长动力学曲线和实际结晶过程一致。研究结果为亚共晶球铁“计算机金相”的形成提出了模拟途径。     

Palm oil‐based unsaturated polyester: Activation energy and swelling properties

In this study, unsaturated polyester (UP) resin based on palm oil was synthesized. Palm oil monoglyceride (POMG) was obtained by alchoholysis process of palm oil at 230°C for 3 h. Then, POMG was treated with maleic anhydride (MA) at different ratio of POMG:MA to produce UP resin. The products were then characterized using Fourier transform infrared (FTIR) spectrometer and proton nuclear magnetic resonance (¹H‐NMR) spectrometer. FTIR and ¹H‐NMR spectrum analyses confirmed that the unsaturated group of MA was chemically attached to POMG. The activation energy of POMG/MA reaction was also studied. The results showed that the ratio of reactants and the presence of 2‐methylimidazole influenced the activation energy of reaction. The prepared UP resin was mixed with 35% of styrene, 0.3% of cobalt naphthenate, and 1% of methyl ethyl ketone peroxide before it was subjected to curing process. The effect of POMG/MG ratio on swelling properties of the cured UP was studied, and the result indicated that toluene and cured UP resin were compatible. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Synthesis and characterization of hydroxyethyl methacrylate/acrylamide responsive hydrogels

Hydrogels based on an aqueous solution of hydroxyethyl methacrylate (HEMA) and acrylamide (AM) in the presence of trithioglycolic acid (TTGA) were prepared under the effect of gamma irradiation. These hydrogels were characterized by IR spectroscopy and thermogravimetric analysis and investigated for temperature‐ and pH‐responsive materials. It was found that TTGA is essential for the formation of HEMA/AM hydrogels at different compositions, in which the gel fraction depends on composition. A binary mixture of HEMA and AM at equal ratios was the critical composition that forms hydrogels, even in the presence of TTGA. The IR spectroscopic analysis showed that the formation of hydrogels depends on hydrogen bonding and crosslinking. The TGA investigations with respect to mass loss and the temperatures of the maximum value of the rate of reaction showed that HEMA/AM hydrogels possess higher thermal stability than that of pure HEMA and this stability increases with increasing ratio of the AM component. Also, it was observed that the temperature of the maximum value of the rate of thermal decomposition reaction depends on hydrogel composition. However, calculations of the activation energy showed that the hydrogel composed of 90% HEMA and 10% AM exhibits the highest thermal stability during the increasing or decreasing rate of reaction. Kinetic studies of swelling in water showed that HEMA/AM hydrogels displayed a temperature‐responsive character within the temperature range 25–30°C, and showed a stepwise swelling behavior in the pH range 2–10, depending on composition. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1105–1115, 2005