我国集中连片特困地区基本教育设施建设途径优化研究 ——以万源市小学教育设施为例

对于我国集中连片特困地区而言, 公共服务设施的配置无疑是新阶段的重 点,其中教育设施的均等化更是该区域公平 和发展的重要保障。为了完善该区域公共 服务设施的布局,促使其实现均等化,研究 以万源市教育设施的建设途径为核心,对万 源市教育设施现状进行了调研,总结了目前 该区域教育设施的建设困境,最终从空间布 局、政策保障和教育结构优化3个主要方面 提出万源市教育设施的建设优化途径,以期 为该区域公共服务设施的均等化提供启发 和借鉴。     

空分设备的氪氙预浓缩技术

大型空分设备的工艺流程不同，采取的氪、氙预浓缩技术也不同。介绍了适用于不同流程的从液氧中提取氪-氙浓缩物和从富氧液空中提取氪-氙浓缩物的氪、氙预浓缩工艺原理、技术参数和特点。     

集中药包爆破破冰的试验研究

黄河凌汛灾害危害面积广,为解决凌汛灾害需进行防凌破冰。分析了2013年²014年在黄河包头地区开河期进行的爆破破冰试验有关数据,总结了药量、破冰体积、药包最佳入水深度、破冰孔距、排距等技术参数之间的关系及有关计算公式,得到药包在最佳入水深度处爆破破冰体积与药量的关系及最佳入水深度;得到破冰工程计算式,通过调节经验系数、药包埋深等,可取得最佳爆破破冰效果,为解决爆破破冰及防凌破冰装备的研制提供参考。     

Semi-analytical solution for free transverse vibrations of Euler–Bernoulli nanobeams with manifold concentrated masses

In the present study, transverse vibrations of nanobeams with manifold concentrated masses, resting on Winkler elastic foundations, are investigated. The model is based on the theory of nonlocal elasticity in the presence of concentrated masses applied to Euler–Bernoulli beams. A closed-form expression for the transverse vibration modes of Euler–Bernoulli beams is presented. The proposed expressions are provided explicitly as the function of two integrated constants, which are determined by the standard boundary conditions. The utilization of the boundary conditions leads to definite terms of natural frequency equations. The natural frequencies and vibration modes of the concerned nanobeams with different numbers of concentrated masses in different positions under some typical boundary conditions (simply supported, cantilevered, and clamped–clamped) have been analyzed by means of the proposed closed–form expressions in order to show their efficiency. It is worth mentioning that the effect of various nonlocal length parameters and Winkler modulus on natural frequencies and vibration modes are also discussed. Finally, the results are compared with those corresponding to a classical local model.     

岩石集中装药爆炸能量分布的计算

本文分析了岩石集中装药爆炸破坏过程,计算了爆破过程所消耗的各种能量的分布。计算结果表明,岩石中2~#岩石硝铵集中药包爆炸所消耗的爆炸气体膨胀能量、冲击波能量分别占装药总能量的50％～60％和10％～20％,无用能约占20％～30％。     

Behavior of Pultruded Fiber-Reinforced Polymer Beams Subjected to Concentrated Loads in the Plane of the Web

Results of the behavior of pultruded fiber-reinforced polymer (FRP) I-shaped beams subjected to concentrated loads in the plane of the web are presented. Twenty beams with nominal depths from 152.4 to 304.8?mm were tested in three-point bending with a span-to-depth ratio of four. Load was applied to the top flange directly above the web—12 without bearing plates and 8 with bearing plates of varying width and thickness. All test specimens failed with a wedgelike shear failure at the upper web-flange junction. Finite-element results support experimental findings from strain gauge and digital image correlation data. Bearing plates increased beam capacity by 35% or more as a function of bearing plate width and thickness. Bearing plates increased average shear stress in the web at failure from 17.4 to 27.2?MPa—below the accepted value of in-plane shear strength (69?MPa). A design equation is presented, and predicted capacities are compared with experimental results. The average value of experimental capacity to predicted capacity is 1.12 with a standard deviation of 0.11 and coefficient of variation (COV) of 0.10 for sections up to 304.8?mm deep.     

浓缩随机载荷谱试验研究

用运输机类型的随机谱载对中间有圆孔的LY12CZ试件进行裂纹形成和扩展试验,然后分别用两种浓缩谱进行试验研究。结果表明在裂纹的形成和扩展阶段对寿命起主要作用的参数影响是有明显差别的。特别是运输机谱中的地-空-地循环,在裂纹扩展的公式中对裂纹形成寿命的贡献估计不足。根据疲劳的材料常数对裂纹扩展的材料常数进行修正得到的计算结果与原谱的试验结果相当吻合。     

动力厂220t/h煤粉锅炉四角燃烧器的改造

介绍了广州石油化工总厂动力厂220t/h煤粉锅炉燃烧系统的改造情况和浓稀相燃烧器的原理、现场安装以及在安装过程中各部分的定位.