仿古建筑檐椽安装施工技术研究

随着人们对民族传统文化的追求日渐强烈,仿古建筑的需求也迅速增长.结合某建筑工程实例,总结了仿古建筑檐椽安装中钢筋混凝土与木质材料结合施工的技术要点,希望为类似工程提供可资借鉴的经验.     

Likelihood ratio tests for the structural change of an AR(p) model to a Threshold AR(p) model

This article considers the likelihood ratio (LR) test for the structural change of an AR model to a threshold AR model. Under the null hypothesis, it is shown that the LR test converges weakly to the maxima of a two‐parameter vector Gaussian process. Using the approach in Chan and Tong (1990)and Chan (1991), we obtain a parameter‐free limiting distribution when the errors are normal. This distribution is novel and its percentage points are tabulated via a Monte Carlo method. Simulation studies are carried out to assess the performance of the LR test in the finite sample and a real example is given.     

Hepatoprotective and hypolipidemic effects of water-soluble polysaccharidic extract of Pleurotus eryngii

The potential biological functions of Pleurotus eryngii have long been described in Chinese traditional medicine. However, little is known about the bioactive components of P. eryngii and their functions in liver injury and high-fat induced animal models. The present study thoroughly investigated the comprehensive functions of water-soluble polysaccharidic extract of P. eryngii (PEPE) using in vivo mouse models and in vitro biochemistry tests. PEPE could significantly increase the activities of antioxidant enzymes and effectively remove the free radicals in a liver-injury mouse model. Furthermore, in a high-fat-load mouse model, PEPE not only remarkably decreased the lipid levels of total cholesterol, total triglyceride, and low-density lipoprotein cholesterol, but also resulted in an increase in high-density lipoprotein cholesterol. Histopathological observations indicated that PEPE could effectively prevent excessive lipid formation in liver tissue. Our data suggest that PEPE can be used as a valuable functional food additive for hypolipidemic and hepatoprotective treatments.     

Leveraging in-situ formation of Ni–Fe nanoparticles to promote the catalytic performance of Ruddlesden-Popper based electrode for symmetrical solid oxide fuel cells

Ruddlesden?Popper layered oxide, La_0.25Sr_2.75FeNiO_7-δ (LSFN) is evaluated as a potential electrode material for symmetrical solid oxide fuel cells. The in-situ formation of Ni–Fe alloy nanoparticles on the LSFN surface in reducing atmosphere can be believed to enhance the activity towards hydrogen oxidation reaction. LSFN exhibit maximum conductivity of 221.2 S/cm and 0.206 S/cm in air and hydrogen environment. Furthermore, LSFN is mixed with GDC powder to form a composite electrode for symmetric solid oxide fuel cells (SSOFC). Results show that with the combination of GDC, the maximum power density of YSZ-based SSOFC enlarges from 232.3 mW cm^?2 to 348.5 mW cm^?2, and related polarization resistance reduces from 0.359 Ω cm² to 0.108 Ω cm². The improved performance is attributed to the enlarged triple-phase boundary with the mixing of GDC. In addition, YSZ-based SSOFC with the LSFN-GDC composite electrode shows a stable performance in intermediate-temperature SSOFCs within 200 h, which indicates that LSFN-GDC composite material is a prospective symmetrical electrode for SSOFC.     

我国建筑业产值利润率与企业技术装备相关性研究

多年来,尽管我国建筑业总产值始终保持了较快增长,但建筑业产值利润率却始终没有较大幅度提高.本文将通过数量关系探究建筑业产值利润率与企业技术装备的关系,从而为多渠道提升建筑业产值利润率提供参考.     

Larger Stabilizing Particles Make Stronger Liquid Marble

Understanding the mechanical stability of granular‐armored liquid marbles is prerequisite for their applications including encapsulation, sensors, microreactions, and miniaturized liquid storage. Most liquid marbles are armored with agglomerated granular structure which complicates the wetting and interacting states of particles, hence, impeding one from understanding the effect of granular size on the mechanical stability of marbles. In this work, using a custom‐built platform to examine the liquid marbles armored by a single layer of uniform grains, it is revealed that larger microsized grains produce stronger liquid marble. This finding is attributed to the gravity‐induced capillary attraction which dominates the interaction of particles and provides additional tension to the granular network of the marble surface, which enhances the mechanical stability of marbles. In addition, different granular network structures are formed at the marble surface by using a binary mixture of monodisperse grains, and their effect on the mechanical stability of marbles is explored. The understandings offer important insights for application involving liquid marbles and provides guideline to formulate robust marble‐based products.     

Focal shifts in focused beams with an elliptical diffracting screen

The approximate analytical formula of the focal shift has been derived for an elliptical diffracting screen that consists of a circular lens and an elliptical aperture. It is found that the focal shift of the beam focused by this elliptical diffraction screen depends not only on the product of the Fresnel number of the focusing geometry and the standard deviation of a mapped function, but also on the ellipticity (the ratio between the minor and the major axes) of the elliptical aperture. The focal shift increases as the decrease in the ellipticity of elliptical aperture. By using an approximate analytical formula and the diffraction integral formula, some numerical simulation comparisons are done. The presented analyses show that the actual analytical expression for the focal shift of a rotationally asymmetric diffraction screen cannot generally be obtained by using the azimuthal average of the screen amplitude transmittance.     

Application of sequential quadratic programming based on active set method in cleaner production

Clean Technologies and Environmental Policy - On the platform of general chemical process simulation software (it was named Optimization Engineer, OPEN), a general optimization algorithm for...