钢结构深化设计与BIM技术的有机结合在中国博览会会展综合体工程中的应用

以中国博览会会展综合体工程为例,针对该项目体量大、单体多、界面复杂、工程进度紧的特点,在深化设计阶段,对钢结构、土建、屋面系统和机电管线进行共同建模.通过建立的建筑信息模型,检查出结构间的软碰撞、硬碰撞及各工种配合的合理性,对实施过程提出了相应的优化建议.     

A novel approach for optimizing the optical performance of the broadband tap coupler

An integrated approach using neural networks, exponential desirability functions and genetic algorithms to optimize parameter design problems with multiple responses is presented. The proposed approach aims to identify the input parameter settings to maximize the overall minimal satisfaction level with respect to all the responses. The proposed approach is illustrated by optimizing the fused process parameters created during fused biconic taper coupler development to improve the performance and reliability of a 1% (1199) single-window broadband tap coupler. The proposed solution procedure was implemented on a Taiwanese manufacturer of fibreoptic passive components. The implementation results demonstrate the practicability of the method. Comparison analysis revealed that the proposed procedure outperformed the traditional Taguchi method in resolving multi-response parameter design problems.     

Classification of MODIS images combining surface temperature and texture features using the Support Vector Machine method for estimation of the extent of sea ice in the frozen Bohai Bay,China

Image classification of frozen areas and adjacent sea ice is important for monitoring the evolution of ocean freezing. This paper proposes a novel approach to the Moderate Resolution Imaging Spectroradiometer (MODIS) image classification and estimation of the extent of sea ice in frozen areas during recent global surface warming hiatus. We derived the texture feature (TF) and surface temperature (ST) from the MODIS image for classification and sea ice detection. We extracted MODIS TF by a grey-level co-occurrence matrix (GLCM), and retrieved the MODIS ST using a split-window method, and finally classified the image using a Support Vector Machine (SVM) convoluting the ST and TF methods. Results were compared and validated with those of conventional spectral-based supervised classification approaches. Results show that the overall accuracy and kappa coefficient (κ) using the proposed method was much higher in comparison with those of the spectral-based maximum likelihood and SVM methods. The SVM fusion ST and TF method was effective and useful for MODIS 500 m image classification and sea ice mapping in frozen area. Combining ST and TF can improve sea ice extent estimation accuracy in the frozen Bohai Bay.     

Ionomer content effects on the electrocatalyst layer with in-situ grown Pt nanowires in PEMFCs

The effects of ionomer contents were investigated in composite electrodes with in-situ grown single crystal Pt nanowires (Pt-NWs) for PEMFCs, including the amount in the carbon matrix and impregnated on the surface of the electrocatalyst layer. The electrocatalyst layer was prepared by growing Pt-NWs directly on the carbon matrix with a simple one-step wet chemical approach at room temperature. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), polarization curve tests, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) were employed to evaluate the ionomer effects. The experimental results showed that the ionomer in the carbon matrix had an influence on the ionic conductivity and aggregation and distribution of the Pt-NWs, and the ionomer impregnated on the surface of the electrocatalyst layer affected the mass transport and ionic conductivity. The performance of the MEA was improved by optimizing the ionomer contents.     

An improved color image watermarking scheme based on Schur decomposition

Multimedia Tools and Applications - With the rapid development of computer technology, the copyright protection of color image is becoming a more and more urgent problem. In this paper, an improved...     

Influence of β‐nucleation on polymorphism and properties in random copolymers and terpolymers of propylene

The competition between α, β, and γ polymorphs has been studied in several random copolymers and terpolymers of propylene, by performing X‐ray diffraction and differential scanning calorimetry experiments. Formation of β‐crystals, achieved by the addition of a β‐nucleating agent, was found to be highly dependent on comonomer type and crystallization conditions. Additionally, the mechanical properties have been evaluated from stress‐strain, microhardness and dynamic‐mechanical thermal analyses. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Physicochemical and sensory characteristics of soya protein isolate hydrolysates with added substrate‐like amino acids

Soya protein isolate (SPI) with or without added substrate‐like amino acid was subject to enzymatic hydrolysis catalysed by commercial proteases (Alcalase 2.4 L, flavourzyme and pancreatin). Addition of a small amount of amino acids (amino acid: SPI = 1: 2500, mol g^?1) during hydrolysis would cause a significantly (P < 0.05) reduced protein recovery, increased degree of hydrolysis, and altered amino acid composition and antioxidant activities of SPI hydrolysates. The SPI hydrolysates prepared with added Asp, Arg or Lys exhibited a higher antioxidant activity than the control. The bitterness of SPI hydrolysates was largely reduced upon addition of Met, Asp or Glu during hydrolysis, whilst the umami taste and mouthfeel‐liking were remarkably increased. Therefore, adding amino acid during hydrolysis is a feasible and beneficial approach to improve both the functional and sensory properties of SPI hydrolysate.     

热处理对12Cr2Mo1R耐热钢断裂韧度的影响

本文对12Cr2Mo1R耐热钢板进行了正火+回火处理(NT),然后再进行模拟焊后热处理(SPWHT),研究了这两种状态钢板在不同温度下的J-Δa阻力曲线,并对断裂韧度J0.2BL值进行了分析。研究结果表明,这两种热处理态组织均以贝氏体为主,所含碳化物都由M3C、M2C、M7C3和M23C6组成,其中M代表合金元素Cr、Mo、Mn和Fe或者它们的组合;在相同热处理的状态下,温度越高,断裂韧度值越高;相同温度情况下,正火+回火态12Cr2Mo1R耐热钢表现出较高的断裂韧度,因为其碳化物含量较小,碳化物之间的间距相对较大。