基于声音信号测量的活体禽蛋胚胎识别

本文将声学理论和声学分析仪器应用于禽蛋胚胎的活体识别中,提出一种半侵入法测量禽蛋胚胎胎动的新方法。这种方法先在胚胎气室的顶部用针扎一个小洞,使活体胚胎的胎动声音信号从气室中放大传出来,然后将胚胎放置于倒圆锥形容器中,再通过声音传感器测量胚胎的胎动。该方法具有操作简单、可靠性高等优点,进行胚胎识别时不会影响胚胎的正常发育,非常适用于禽蛋孵化过程中的育种筛选以及长期监测。     

一种基于SSI的天气现象评价系统的研究

为了提高某市的天气预报准确率,开发了一种采用SSI技术研发的天气现象评价系统.首先阐述了SSI技术,以及为什么采用SSI技术作为该系统的构架,然后分析了该项目的市台需求和解决方案,详细地描述了iBATIS2.3技术在该项目中的应用.最后根据国家气象局制定的评定规则,给出了本系统评定天气现象的最终结果,并对最终结果进行了分析.     

喷涂纯聚脲技术在水利工程防护中的应用与展望

纯聚脲技术是成功实现水利工程聚脲防护的关键。首先科学阐述了聚脲的定义,全面介绍了纯聚脲技术应用于水利工程防护的技术优势,详细探讨了纯聚脲技术施工工艺要领,深入分析了水利工程纯聚脲和假聚脲的工程案例。     

三维运动连续进料式混合搅拌机

文章设计了一种新型三维运动连续进料式混合搅拌机。其结构包括机架、混合桶、搅拌轴、搅拌电机、旋转电机、旋转轴、集电环和电刷。该混合搅拌机一方面将混合桶的旋转和混合桶内搅拌轴的旋转结合在一起,大幅度提高了混料的效率,另一方面将旋转轴作为进、出料口,可以进行连续性装填,提高了效率,降低了能耗。图1参14     

消除或改善短柱的抗震措施

随着大跨度和超高层结构的发展以及建筑错层、转换层、设备层和地下车库结构的需要,短柱的出现不可避免.结构中短柱的剪切破坏是造成结构破坏,甚至引起结构倒塌的主要原因.本文介绍了钢筋砼短柱判别方法,并分别从构件材料性能、抗震构造措施、非传统柱截面形式、约束混凝土柱、抗震结构体系5个方面采取措施,来增强钢筋砼短柱的延性和抗剪承...     

Influence of oil mist parameters on minimum quantity lubrication – MQL grinding process

Promising alternatives to conventional dry and fluid coolant applications are minimum quantity lubricant (MQL) or near dry grinding. Despite several researches, there have been a few investigations about the influence of MQL parameters on the process results, such as oil flow rate, air pressure, MQL nozzle position and distance from the wheel–workpiece contact zone. The current study aims to show through experiment and modeling, the effects of the above parameters on grinding performance such as grinding forces and surface roughness. The results show that the setting location of the nozzle is an important factor regarding the effective application of MQL oil mist. It has been shown that optimal grinding results can be obtained when the MQL nozzle is positioned angularly toward the wheel (at approximately 10–20° to the workpiece surface). In addition, it is found that the efficient transportation of oil droplets to the contact zone requires higher mass flow rate of the oil mist towards the grains flat area and longer deposition distance of an oil droplet. Applying the new setup, considerable reduction in the grinding forces and surface roughness has been achieved.     

Three-dimensional structure analysis by X-ray micro-computed tomography of macroporous alumina templated with expandable microspheres

The three-dimensional (3D) structures of macroporous alumina, produced by a novel method that combines gel casting with expandable polymeric microspheres as a sacrificial templating material, have been characterised by X-ray micro-computed tomography (μ-CT). The grey-scale intensity tomogram data produced by the X-ray μ-CT was segmented into porous and solid phases and the individual pores were identified. We compared two-dimensional slices of the analysed data with the corresponding scanning electron microscopy images and showed that the structural features of the pores were well reproduced in the X-ray μ-CT images. 3D visualisations of the pore structure and the pore network were also shown. The open porosity obtained from X-ray μ-CT corresponded well with the porosity derived from mercury porosimetry for pores larger than the voxel dimension (3 μm). The quantitative analysis also yielded information on the spatial variations in porosity and the number of connected neighbours of pores. The 3D data was used to relate the calculated permeability to the open porosity.     

带悬伸段柱计算长度的讨论

运用逐段分析的方法,并结合转角—位移法基本方程的推导,建立了考虑剪切变形影响的带悬伸段柱的稳定方程.对比分析了有关文献给出的轴力作用在柱顶且不考虑剪切变形影响的相关计算长度系数的拟合公式,给出了各公式拟合的计算长度系数用来求临界荷载时造成的误差;指出了柱脚铰接和刚接时临界荷载差值的关系;给出了轴压力对转角约束刚度的影响分析.以上分析结论对工程设计有一定的使用价值.     

The performance of a surface-applied corrosion inhibitor for the carbon steel in saturated Ca(OH)2 solutions

In the present work, the performance of an amino alcohol based surface applied inhibitor was studied by the electrochemical techniques in saturated Ca(OH)₂ solutions. The surface morphology of the carbon steel was observed by scanning electron microscope, and the energy diffraction spectrum was also tested. Results showed that the inhibitor used in this work demonstrated obvious inhibition efficiency on the carbon steel in saturated Ca(OH)₂ solutions. The inhibition mechanism of the inhibitor lies in the quick adsorption of the active component on carbon steel surface.     

Rock matrix-fractured media model for heterogeneous and fractured coal bed

Coal was considered rock matrix-fractured media composed of rock matrix and fractures, and the rock matrix-fractured media model for heterogeneous and fractured coal bed was presented. In this model the rock matrix is heterogeneous, and the mechanical parameters such as elastic modulus and strength follow Weibull distribution. Fractures in coal bed were generated with the discrete fracture network method, and the properties of fractures were simulated with Desai element. Then the virtual generating system (VGS) of natural heterogeneous and fractured coal bed was developed in Matlab 6.0. The coupled model of gas flow and deformation process based on the rock matrix-fractured media model method and VGS for heterogeneous and fractured coal bed was presented, and the numerical code was developed in Matlab 6.0. The gas flow process in the heterogeneous and fractured coal bed was simulated in a numerical case. The main conclusions are: 1) The natural heterogeneous and fractured coal bed could be simulated by the rock matrix-fractured media model and VGS; 2) The fractures connected with the well have much more effects on gas flow than those non-connected.