彬长矿区4号煤层煤质特征及洁净等级划分

为实现彬长矿区优质煤炭资源的清洁高效利用,在对彬长矿区以往勘查钻孔的煤质化验资料统计分析的基础上,系统分析了该矿区主采煤层4号煤的煤岩、煤质特征,论述了硫分、灰分、挥发分、发热量和有害微量元素的分布规律,依据最新煤炭资源潜力评价提出的煤炭洁净等级6级划分方案,选用灰分、硫分、有害元素(F、Cl、As及Pb)6个评价指标对矿区内4号煤层的煤炭资源洁净等级进行了初步划分。彬长矿区4号煤层以低硫、低中灰、中高挥发分、特高热值不黏煤为主,局部含小范围的弱黏煤,彬长矿区4号煤层原煤洁净等级为Ⅲ级,属较好洁净煤;浮煤洁净等级为Ⅱ级,属好洁净煤。整个矿区内4号煤层原煤洁净等级以Ⅲ级较好洁净煤为主,分布区占矿区面积的73.03%,仅在矿区西部洪家镇—巨家镇一带和中东部出现小范围的Ⅳ级中等洁净煤分布区,面积占比为26.97%。     

厦门市汀溪灌区总干渠洪水复核方法探讨

汀溪灌区作为汀溪水库群的农业供水对象,其灌溉用水量的大小直接关系到汀溪水库群向翔安、同安两区的水资源供需平衡,甚至影响厦门市水资源配置方案。但由于灌溉面积和渠道功能发生变化,有必要进行洪水分析复核从而重新确定工程规模。本文对汀溪灌区总干渠洪水复核方法进行探讨,供参考。     

Determination of the normal horizontal working area: a new model and method

A new model was developed for the determination of the normal horizontal working area by extending Squires' concept. The elbow not only moves freely straight ahead, but also to the right and left of the operator in describing the working area. The parametric equations developed in this research enabled us to determine working area curves which lie on both sides of the body median. Experimental results showed that the relevant anthropometric parameters were poorly correlated. A new method was developed to determine correctly the normal horizontal working area curves for the 5th, 50th, and 95th percentiles of male and female populations. When compared to the corresponding curve generated by the new method, Squires' curve for the 10th percentile male considerably overestimated the normal horizontal working area to the right of the body median and underestimated it to the left.     

岩溶地面塌陷区地质灾害治理及桩基设计探究

对徐州岩溶地区高层建筑的地面塌陷情况进行了分析,并对软土地区桩基设计计算方法、地基模型及桩基沉降变化模型作了详细探究,从而使桩基设计技术更加完善。     

节能示范区公共设施建设管理问题研究

节能示范区是低碳经济发展过程中的阶段性产物,而节能示范区的低碳节能的公共设施管理已经成为迫切需要解决的重要问题。通过节能示范区公共设施建设管理和使用中存在的问题分析,探讨解决方法与途径。     

Packing equal circles into a circle with circular prohibited areas

The paper considers the problem of packing a maximal number of identical circles of a given radius into a multiconnected domain. The domain is a circle with prohibited areas to be finite unions of circles of given radii. We construct a mathematical model of the problem and investigate its characteristics. The starting points are constructed in a random way or on the ground of the hexagonal lattice. To find the local maxima, a modification of the Zoutendijk method of feasible directions and a strategy of active inequalities are applied. We compare our results with the benchmark instances of packing circles into circular and annular containers. A number of numerical examples are given.     

中原经济区郑州都市区建设战略研究

旨在通过对郑州都市区发展战略的研究,对接和落实中原经济区的战略构想,进一步促进郑州都市区更好更快发展,增强郑州都市区的核心凝聚力、竞争力和影响力,把郑州都市区建设成为中原经济区核心增长区和全国重要的区域性中心城市。     

Biogenerated silica nanoparticles synthesized from sticky,red, and brown rice husk ashes by a chemical method

An inexpensive chemical method was used to synthesize biogenic mesoporous silica (m-SiO₂) from rice husk ash (RHA). A comparative study was carried out to produce silica nanoparticles (S-SiO₂, R-SiO₂, and B-SiO₂) from three type of rice husk ashes (sticky, red, and brown). The microstructure of m-SiO₂ was dependent on the geographical provenance and the types of RHA. An analysis of the SEM and TEM micrographs reveals that the S-SiO₂ nanoparticles had a clustered spherical shape, while R-SiO₂ and B-SiO₂ nanoparticles were found to be purely spherical. The average crystallite size of S-SiO_2, R-SiO₂ and B-SiO₂ nanoparticles evaluated from the TEM measurements were observed to be 50, 20 and 10 nm, respectively. The XRD pattern of silica nanopowders had an absence of sharp peaks that confirmed the amorphous nature of the material. The Fourier transform infrared (FTIR) spectra of silica nanoparticles showed the symmetric Si–O and O–Si–O stretching bond vibrations at 462, 1088, and 1098 cm⁻¹. The surface area of S-SiO_2, R-SiO₂ and B-SiO₂ nanopowders was measured to be 7.5513, 201.45, and 247.18 m² g⁻¹, respectively. The surface area of uniformly-distributed spherical nanoparticles of B-SiO₂ was observed the highest, which can be applied for the application of energy storage and drug delivery systems.     

On the formation mechanisms of fine granular area (FGA) on the fracture surface for high strength steels in the VHCF regime

The fine granular area (FGA) plays a crucial role in the VHCF regime. However, so far, the uniform understanding or conclusion about the formation mechanism of FGA has not been drawn. In view of the significance of FGA, the current studies on FGA, i.e., the FGA size, the stress intensity factor range at the periphery of FGA, the crack initiation and growth process in FGA, and the formation mechanisms of FGA, are reviewed in the present paper. The role of internal hydrogen in the VHCF regime is further discussed. In the end, two important definite conclusions are drawn based on the present investigations.