Theoretical study on the electronic properties and stabilities of low-index surfaces of WC polymorphs

The low-index surfaces of WC polymorphs are calculated using the first-principles method based on density functional theory. It is found that there are large relaxations within the top three layers for all termination surfaces, and charge density falls greatly toward the vacuum. The outermost and second interlayer relaxations for C-terminated surfaces are much larger than those for W-terminated surfaces. The surface energies for all low-index surfaces are large which is due to the breaking of strong W–C bonds. For both WC polymorphs, the C-termination surfaces are thermodynamically more unstable than W-terminated surfaces over the whole range of carbon chemical potentials considered in this paper; the most stable surfaces correspond to the (0 0 1) surface with W termination for α-WC, and the (0 0 1) surface with WC termination for β-WC.     

聚丙烯酸甲酯齐聚物的合成及乙氧基化

以四氩呋喃为溶剂,正十二硫醇为链转移剂,采用自由基溶液聚合的方法合成了聚丙烯酸甲酯齐聚物.考察了单体滴加时闻对黏均分子量的影响,确定滴加时间为40 min可以得到较低黏均分子量的聚丙烯酸甲酯齐聚物.在自制的插入式酯基乙氧基化催化荆MCT-09催化下成功地对聚丙烯酸甲酯齐聚物进行了乙氧基化反应.反应结果显示,随着反应进行...     

循环载荷作用下盐岩力学特性响应研究

 通过模拟储气库运行围岩受载情况,对层状盐岩储气库围岩中常见盐岩及含夹层盐岩进行应力水平不断提高的反复加卸载试验研究。试验结果表明：与单调加载相比,循环载荷下芒硝试样强度明显降低;含钙质泥岩夹层芒硝的强度高于纯芒硝,但由于受夹层的影响,峰值点对应应变低于纯芒硝。与其他岩石明显不同,在初期阶段,盐岩试样循环加卸载曲线基本呈线性并重叠,随应力水平及循环次数的提高,滞回环现象有轻微表现,但面积很小。后期卸载过程中盐岩的杨氏模量略高于加载过程,除卸载过程弹性变形恢复滞后外,还受加载过程中耦合的塑性变形因素影响。由于钙质泥岩夹层的变形能力相对较弱,含夹层芒硝的杨氏模量稍高于芒硝,同时,在反复循环卸载过程中的变形恢复也大于纯盐岩。总体上看,盐岩在加卸载过程中杨氏模量基本不随应力水平及加卸载次数的变化而变化。同时,即使进入屈服破坏阶段,也没有出现一般岩土材料加卸载杨氏模量随屈服应力降低而降低的现象。根据能量观点分析,循环载荷作用下强度降低幅度与循环次数及累积滞回环面积相关。本次试验中,5个试样循环加卸载作用过程中,加卸载曲线几乎重合,滞回环很小,因而强度降幅也很小。据此推断,在储气库反复加卸载运行过程中,围岩强度基本不会受循环次数的影响;但大幅度的压力波动有可能产生能量累积,从而影响其强度与寿命。     

Mo2C intermediate layers for graphite-Cu system using the molten salt method

A simple and effective route for the direct synthesis of Mo₂C coatings on graphite matrix is introduced for the joining of copper alloy heat sinks to graphite materials in Tokamak devices. The composition and microstructure of the Mo₂C coatings on graphite, and the wetting behaviors of molten copper on coated and uncoated graphite were investigated. Results indicated that the Mo₂C coatings were of several tens of micrometers depth in the graphite matrix. The coatings greatly improved the wettability of graphite by copper, and copper could be infiltrated into Mo₂C-coated graphite matrix without external pressure. The strong interfacial bonding between copper and the graphite matrix was obtained by utilizing the mechanical interlocking within the space limitations of the graphite network. The Mo₂C-modified graphite-copper samples resulted to have the average shear strength of 17 ± 4 MPa.     

粗煤气铁矿颗粒床高温除尘联产直接还原铁工艺及估算

在煤灰熔点高于直接还原铁还原温度200℃的条件下,以直接还原竖炉作为移动颗粒床除尘器为核心技术的3段连续除尘,以铁矿煤球团为直接还原铁原料和移动颗粒床除尘颗粒,粗煤气显热可以直接用于生产直接还原铁。粗煤气显热约占煤炭气化热值的13%,估算联产直接还原铁显热利用效率可达70%以上,与现有的粗煤气废锅发电比,综合热效率提高约2倍,直接还原铁能耗303kg（C）/t.Fe,可以实现温室气体近零排放,减排CO₂约1.7t/t.Fe。可以在不减少粗煤气化学热能（H₂+CO）,联产直接还原铁的同时解决粗煤气的高温除尘与净化问题。     

降低焦炭水分的措施及效果

介绍了某焦化厂降低焦炭水分的措施及使用效果。实践证明,采用低水分熄焦方法可缩短熄焦时间,减少水的用量,降低焦炭水分,从而以低的投入成本收到良好的效果。     

Facile fabrication of ZrO2 hollow porous microspheres with yeast as bio-templates

ZrO₂ hollow porous microspheres have been fabricated successfully using living yeast cells as bio-templates through a facile ageing process at lower crystallizing temperature. XRD, SEM, FT-IR and N₂ adsorption-desorption were used to characterize ZrO₂ hollow microspheres. The results showed that the inorganic-organic hybrid hollow microspheres were fabricated at 100 °C and ZrO₂ hollow microspheres with tetragonal phase and porous structure were obtained at 300 °C. The crystallization temperature of ZrO₂ decreased obviously due to the inducting of bio-molecules. The as-prepared hollow microspheres are approximately ellipsoid. The shells of these hollow microspheres are porous, which are composed of some nanoparticles with size of ∼20 nm. The formation mechanism of ZrO₂ hollow microspheres was proposed and discussed tentatively.     

浅谈环保型建材在住宅建筑中的应用

根据我国建材市场的现状,分析了传统建筑装饰材料的污染及其原因,阐述了环保型建材的使用情况,提出了环保型建材应用于住宅建筑的必要性。     

基于硬度的矸石选择性破碎分选的可行性探讨

基于选煤厂外排矸石中砂岩、高岭岩和煤矸石硬度的差别,通过破坏载荷试验以及破碎筛分、发热量测定试验,探讨砂岩、高岭岩和煤矸石选择性破碎分选的可行性。结果表明,在硬度差别比较明显的情况下,通过硬度进行选择性破碎分选是可行的。     

十二烷基二苯醚单/双磺酸盐的合成

以十二醇、二苯醚和发烟硫酸为原料合成了十二烷基二苯醚磺酸盐.考察了物料摩尔比和反应温度对十二烷基二苯醚磺酸盐组成的影响,并采用高效液相色谱/质谱对磺化产物进行了分析表征.结果表明:十二烷基二苯醚进料量的增加有利于单磺酸盐的生成;温度低于50℃时,温度的升高有利于双磺酸盐的生成;而温度大于50℃时,温度的升高有利于单磺酸...