资源整合型沙坪煤矿设计综述

 文章介绍了沙坪煤矿作为山西省实施“关小建大、资源整合”煤炭产业政策第一个示范性资源整合项目，将九座地方小窑整合一起，仅用了14个月建成一座大型现代化煤矿的设计特色，提出了简化生产系统、合理集中生产、加快煤矿建设速度、降低投资、提高综合效益的做法，可供条件类似煤矿设计、建设中借鉴。     

Physico-chemical concept of drag reduction nature in dilute polymer solutions (the Toms effect)

The physicochemical concept of turbulent drag reduction (the Toms effect) integrates physicochemical characteristics of polymer solutions with hydrodynamic and rheological flow parameters into a generalized equation, where the increment in volumetric flow rate Q_P is a function of the external shear stress τ_w, temperature, volume of macromolecular coils with immobilized solvent V_c and a function of their volume fraction Ψ = C · [η]/(1 + C · [η]). The Q_P depends on the coil intrinsic elasticity [G] = kT/V_c as well. This model allows one: (1) to describe the Toms effect in terms of useful elastic work spent by macromolecular coils with immobilized solvent to overcome the frictional forces (i.e. the forces of intermolecular interactions), (2) to forecast the initial conditions of the Toms effect (τ_* ≈ (RT)/(M · [η])) and (3) to explain the unusual temperature dependence of the polymer solutions flow.     

现浇钢筋混凝土楼板裂缝控制措施及修复方法

对某工程钢筋混凝土楼板产生的几类裂缝进行了原因分析,阐明了裂缝对结构的危害性,提出了该工程相应的裂缝修复处理方法,并从施工方面提出了针对性的预防和控制措施,为解决相同类型的工程问题积累了经验。     

Methanol synthesis from CO2 hydrogenation over CuO-ZnO-ZrO2-MxOy catalysts (M=Cr,Mo and W)

Three CuO-ZnO-ZrO₂-M_xO_y (CZZM, M = Cr, Mo and W) mixed oxides were prepared by a co-precipitation method and tested as catalysts for methanol synthesis from CO₂ hydrogenation. The catalysts were characterized by XRD, N₂ adsorption/desorption, XPS, reactive N₂O adsorption, H₂-TPR, and CO₂-TPD techniques. The results indicated that the methanol selectivity and yield of the CuO-ZnO-ZrO₂ catalyst noticeably increased by the additions of MoO₃ and WO₃, but slightly decreased by Cr₂O₃ doping. Combining with the characterization results, the difference in methanol yield over the three catalysts can be attributed to the differences in their BET specific surface areas (S_BET) and adsorption capacities for CO₂, while the methanol selectivity is closely correlated to the ratio of surface contents of Zn to Cu, as well as the fraction of strong basic sites in the total basic sites of the investigated catalysts.     

Dry reforming of methane with isotopic gas mixture over Ni-based pyrochlore catalyst

Dry reforming of methane was carried out using isotopic ¹³CO₂ and C¹⁸O₂ gases over a Ni-based pyrochlore catalyst that was synthesized using the modified Pechini method. In this method, 1 wt% Ni was doped into the La₂Zr₂O₇ pyrochlore structure. The catalyst was characterized by H₂-TPR, TPO, and XRD and tested for its methane reforming activity under CO₂ dry-reforming reaction conditions.The results of repeated TPR/TPO cycles up to 950 °C showed that the consecutive TPR profiles were nearly identical, indicating that the catalyst was stable at high temperatures, and that the nickel oxidation/reduction processes were reversible. The dry-reforming experimental results using labelled ¹³CO₂ gas showed the syngas production for this material proceeded through the activation of CH₄ with O that came from breaking one of the CO bonds of CO₂ with the latter reaction (CO₂ activation) likely occurring at oxygen vacancies at or near the Ni particle-pyrochlore interface. It was also found that only a small portion of the CO originated from CH₄. A variation of the same experimental test, but using ¹²C¹⁸O₂, revealed only ¹²C¹⁸O was formed and no ¹²C¹⁶O was detected, ruling out the possibility of reaction with the lattice oxygen in the catalyst structure with this material. Over this catalyst, the activated CH₄ appeared to dissociate to elemental carbon on the catalyst surface, which was determined to be the source of carbon from a post reaction TPO of the catalyst that was exposed to the ¹³CO₂¹²CH₄ mixture. No carbon deposition appeared to originate from ¹³CO₂.     

Methods of analysis modified size exchange chromatography method for analysis of heavy oil residues

A modified size exchange chromatography method is used to obtain molecular weight distributions, average molecular weight, and other characteristics of heavy oil residues: coal asphalt, petroleum asphalt, vacuum residue oil, and ethylene residue oil. This method can be applied for developing and studying processes involved in hydrogenation of heavy oil residues, road asphalt production, and coal liquefaction.     

电气工程造价控制存在问题分析及解决措施

分析了电气工程造价控制中存在的问题,阐述了制约电气工程造价控制问题的因素,并结合工作经验,提出了控制电气工程造价的有效措施,以期利用科学的手段解决电气工程造价的控制问题,使电气行业能有更好的发展前景。     

人防工程通风设计中的一些问题

针对人防工程通风设计中容易发生的一些问题进行了探讨,阐述了过滤吸收器、油网过滤器、通风密闭阀门的选择方法,指出人防工程平战功能转换措施和系统的战时控制方法设计必须齐备详实。     

论述大板基础典型施工方案

介绍了大板基础施工的特点、应用范围及工艺原理,并从前期工作、基坑开挖、底板基础施工等方面入手,详细分析了大板基础施工过程中应注意的操作要点,指出大板基础施工工艺先进、实用性强,具有良好的经济效益和社会效益。     

Continuous preparation of multiscale reinforcement by electrophoretic deposition of carbon nanotubes onto carbon fiber tows

The simple and continuous deposition of carbon nanotubes onto the surface of carbon fiber tows, using ethanol as a dispersive medium, was achieved by the electrophoretic process. The resulting materials showed a uniform distribution of carbon nanotubes on the fiber surface. Such a continuous process provides industrial potential for preparing a multiscale carbon nanotube-carbon fiber reinforcement.