厚松散层薄基岩下综采液压支架选型试验分析

针对淮南潘二矿厚松散层薄基岩地质条件下1811(1)工作面开采的液压支架选型,采用数值模拟及相似模拟手段,对1811(1)工作面开采三带发育高度进行了分析研究,并最终确定采用ZZ7200-13/26型支撑掩护式液压支架,通过现场矿压显现规律的实测确定ZZ7200-13/26型支撑掩护式液压支架选型的合理性。     

Low-temperature ECR-PEMOCVD deposition of high-quality crystalline gallium nitride films: A comparative study of intermediate layers for growth on amorphous glass substrates

A low temperature growth method based on an electron cyclotron resonance plasma-enhanced metal organic chemical vapor deposition system (ECR-PEMOCVD) was proposed for the growth of GaN (Gallium nitride) films on ordinary amorphous soda-lime glass substrates. To alleviate the large lattice mismatch between GaN film and glass substrate and improve the heat dissipation performance for potential optoelctrical device application, five intermediate layers (Cu, Ni, Ti, Ag, and ITO) were deposited on the glass substrate before the growth of GaN. A comparative study was performed through structural analysis of the as-grown GaN films with various intermediate layers investigated by means of in-situ reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD), and atomic force microscopy (AFM). The results indicate that the Ti intermediate layer has a great advantage over other intermediate layers in view of crystalline quality and smooth surface, therefore is more suitable and preferred for the potential application in optoelectronic devices.     

Enhanced densification of thin tape cast Ceria-Gadolinium Oxide (CGO) layers by rheological optimization of slurries

Optimized CGO-based slurries are formulated and shaped into thin dense layers via a tape-casting process. The formulation is adjusted with respect to the rheological behaviour. The internal structure and flow properties of slurries are explored with the aim of identifying the required conditions to obtain thin dense CGO layers at reduced sintering temperatures (1200 °C). We demonstrate a correlation between the rheological properties of the slurries, the sintering behaviour and the microstructure of the resulting tapes. Remarkably, a dense CGO layer less than 20 µm thick is obtained with a non-congested slurry, having optimized ceramic loading and liquid-like behaviour.     

七层熔融共挤出石头纸在昆钢的工业化实践

通过制备印刷层、遮盖层、发泡层、增强层母料,再将上述各挤入层的熔融胶状物通过同一模头挤出发泡,经常规三辊压光、冷却、牵引、收卷,即得到七层熔融共挤出石头纸。采用该方法制备的石头纸,挺度好、印刷适应性好,比重低,不透明度高、平滑度好、厚度均匀,各项性能指标符合GB/T22806-2008"白卡纸"的性能指标要求,可用于印制美术印刷品、卡片、名片、包装纸盒等。该制备方法在云南昆钢石头纸环保材料有限得到工业化实践。     

水泥土土工格栅地基处理应用分析

作为一种新的地基处理方法,水泥土土工格栅结构复合地基因工序简单、成本低廉、施工方便、效果理想而被广泛应用。许昌市某22层酒店工程中,采用水泥土土工格栅结构复合地基,减少了挖填土方量,工艺简单,可缩短工期50%,节省造价约30%。     

Introducing immobilized metal phthalocyanines as spin-injection and detection layers in organic spin-valves: Spin-tunneling and spin-transport regimes

In (organic) spin-valve devices, two ferromagnetic electrodes having different coercive fields are used to achieve an anti-parallel configuration necessary to enforce spin-flip of electrons within the semiconductor spacer layer. Here we report a use of immobilized magnetic organic molecules as spin-injection and spin-detection layers to form pre-fabricated spin-valve devices. While immobilized manganese- and nickel-phthalocyanines were used as spin-injection and spin-detection layers both, copper phthalocyanine acted as the spacer layer in the all-organic spin-valve devices.In the current-voltage characteristics of parallel and anti-parallel configurations, the electrical resistance was always higher for the latter one implying positive magnetoresistance in the material. By lowering thickness of the spacer layer down to a monolayer region, a tunneling regime could be achieved; spin-flip process in organic spin-valves has been found to be facile in the tunneling regime as compared to that during the spin-transport process through a thicker spacer layer.     

Effect of seed layer on the growth of rutile TiO2 nanorod arrays and their performance in dye-sensitized solar cells

In order to improve the performance of TiO₂ photoanode-based dye sensitized solar cells (DSSCs), rutile TiO₂ nanorod arrays (NRAs) were grown on SnO₂:F (FTO) conductive glass coated with TiO₂ seed layer by a hydrothermal method. The TiO₂ seed layer was obtained by spin-coating titanium tetraisopropoxide (TTIP) isopropanol solution with concentration in the range of 0~0.075 M. Then the effect of the thin TiO₂ seed layer on the crystal structure and surface morphology of TiO₂ NRAs and the photoelectric conversion properties of the corresponding DSSCs were investigated. It is found that TiO₂ NRAs are vertically oriented, about 1.7 μm long and the average diameter is about 35 nm for the samples derived from TTIP in the range of 0.005~0.05 M, which are more uniform and better separated from each other than those without TiO₂ seed layer (average diameter 35~85 nm). The photoelectric conversion efficiency of DSSCs based on TiO₂ NRAs with TiO₂ seed layer is larger than that without TiO₂ seed layer. Typically, the energy efficiency of DSSCs obtained from the seed solution of 0.025 M TTIP is 1.47%, about 1.8 times greater than that without TiO₂ seed layer. The performance improvement is attributed to the thinner, denser and better oriented NRAs grown on seeded-FTO substrate absorbing more dye and suppressing charge recombination at the FTO substrate/electrolyte interface.     

Evaluation of tensile load-strain characteristics of geogrids through in-soil tensile tests

This paper evaluates in-soil tensile load-strain characteristics of geogrids with the help of a custom designed and developed in-soil tensile setup in the laboratory. Displacement controlled in-soil tensile tests were carried out to evaluate the effect of normal stress, soil type, and presence of sand-sandwiched layer, on the tensile load-strain characteristics of geogrid. Confinement of geogrid within the soil and application of normal stress were found to increase the mobilized tensile load and secant tensile stiffness of geogrid. Secant stiffness improvement factors were determined to quantify the improvement in tensile load-strain characteristics of geogrid under confinement, on comparison to in-isolation values. Geogrid was observed to exhibit lower secant tensile stiffness when embedded in marginal soil, moist-compacted at wet of optimum. However, the concept of sand-sandwiched geogrid was found to improve the tensile load-strain behaviour of geogrids embedded in marginal soil compacted at wet of optimum.     

Structural and opto-electrical properties of pyrolized ZnO-CdO crystalline thin films

A series of ZnO-CdO thin films of different molar ratios of Zn and Cd have been deposited on glass substrate at substrate temperature ~ 360 ℃ by the spray pyrolysis technique at an ambient atmosphere. X-ray diffraction (XRD) studies confirmed the polycrystalline nature of the film and modulated crystal structures of wurtzite (ZnO) and cubic (CdO) are formed. The evaluated lattice parameters, and crystallite size are consistent with literature. Dislocation density and strain increased in the film as the grain sizes of ZnO and CdO are decreased. The band gap energy varies from 3.20 to 2.21 eV depending on the Zn/Cd ratios in the film. An incident photon intensity dependent I-V study confirmed that the films are highly photosensitive. Current increased with the increase of the intensity of the light beam. The optical conductivity and the optical constants, such as extinction coefficient, refractive index and complex dielectric constants are evaluated from transmittance and reflectance spectra of the films and these parameters are found to be sensitive to photon energy and displayed intermediate optical properties between ZnO and CdO, making it preferable for applications as the buffer and window layers in solar cells.