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61.
62.
基于平煤十二矿深部开采面临的排矸量大、辅助运输困难、矿区环境污染以及常规充填面产能不足工程背景,创新了矸石充填与垮落法混合综采技术并阐述了其技术内涵。采用理论分析、物理相似模拟和现场实测方法系统地研究了混合综采工作面覆岩运移规律和空间结构特征。通过理论分析得到了不同充实率状态下混合综采工作面覆岩空间结构特征;物理相似模拟结果表明,混合综采工作面充填段基本顶仅发生弯曲下沉,而垮落段直接顶垮落、基本顶断裂,垮落段基本顶平均下沉量是充填段的4.2倍,覆岩空间结构表现出明显的非对称特征。矿压实测数据显示,充填段采场无明显的来压现象,垮落段来压现象显著,初次来压步距约30 m,周期来压步距约22 m,动载系数达1.7左右;岩层钻孔窥视结果观察到充填段顶板完整,覆岩空间结构呈现“两带”发育特征;垮落段覆岩结构呈“三带”发育特征,混合综采工作面覆岩非对称性空间结构特征显著。 相似文献
63.
段莉萍 《兵器材料科学与工程》1997,20(4):68-71
论述了用高技术贮氢材料的某些功能来改造现有的兵器,以及在研制新型兵器中,引入高技术新材料。为某些兵器所面临的技术难题,指出了有效的解决途径。 相似文献
64.
ESR and Raman spectroscopy have been used to characterize monolayers of vanadia, which had been immobilized on titania and on a 20% TiO2/80% SiO2 mixed oxide support from a vanadyl alkoxide precursor. Characteristic vibrations observed in the Raman spectrum, as well as UV-visible reflection data, indicate that the most abundant vanadia species on the surface consists of disordered polymeric arrays: the central vanadium ion is surrounded by the tightly bound vanadyl oxygen, four oxygen ions in the basal plane, and a distant sixth oxygen ligand in bridging position to the support. From the ESR spectra the principal values ofg andA tensors are obtained, and their dependence on the support material and on the vanadia loading is investigated. Comparison with TPR measurements indicates that for structurally and chemically similar catalysts, the ESR-derived deviationg = g – g
e from the free electrong value provides a useful measure of the V=O bond strength. 相似文献
65.
核函数是SVM(Support Vector Machine,支持向量机)的重要组成部分,核函数的选取对分类效果有明显的影响。该文把混合核函数引入到变压器状态评估中。实例分析表明,混合核函数支持向量机提高了状态评估的准确率。 相似文献
66.
67.
John W Cone Wilhelmina Clin-Theil Aart Malestein Arie Th van 't Klooster 《Journal of the science of food and agriculture》1989,49(2):173-183
The degradability of starch from various feedstuffs was investigated in vitro by incubation of 500-mg amounts in 50 ml of a 3:1 rumen fluid/buffer solution at 39°C for 6 h. The rumen fluid was obtained from one of three cows fed on hay or hay and concentrate. The degree of degradation after 6 h incubation varied strongly for the 23 feedstuffs investigated. The degradation of starch from the same feedstuff in rumen fluid from a hay-fed cow was significantly lower than in rumen fluid from a concentrate-fed cow. It seemed that differences in degradability between feedstuffs were not determined by the ration of the donor cow, but merely by the properties of the starch. Processed feedstuffs showed a higher degradation of their starch than the unprocessed feedstuffs, independent of the ration of the donor cow. Particle size influenced degradation, but not of the starch of tapioca meal. A fairly constant ranking in degradability between the various feedstuffs was found. Fermentation of mixtures of feedstuffs showed about the same rate of degradation as found for the single products. Only when great differences in the degree of degradability existed was the degradation of the total starch enhanced. The time of collection of rumen fluid strongly influenced the in-vitro degradation of starch. 相似文献
68.
Tae Hoon Lee Aydin Ozcan Inho Park Dong Fan Jun Kyu Jang Paulo G. M. Mileo Seung Yeon Yoo Ji Soo Roh Jun Hyeok Kang Byung Kwan Lee Young Hoon Cho Rocio Semino Hyo Won Kim Guillaume Maurin Ho Bum Park 《Advanced functional materials》2021,31(38):2103973
Incorporation of defects in metal–organic frameworks (MOFs) offers new opportunities for manipulating their microporosity and functionalities. The so-called “defect engineering” has great potential to tailor the mass transport properties in MOF/polymer mixed matrix membranes (MMMs) for challenging separation applications, for example, CO2 capture. This study first investigates the impact of MOF defects on the membrane properties of the resultant MOF/polymer MMMs for CO2 separation. Highly porous defect-engineered UiO-66 nanoparticles are successfully synthesized and incorporated into a CO2-philic crosslinked poly(ethylene glycol) diacrylate (PEGDA) matrix. A thorough joint experimental/simulation characterization reveals that defect-engineered UiO-66/PEGDA MMMs exhibit nearly identical filler–matrix interfacial properties regardless of the defect concentrations of their parental UiO-66 filler. In addition, non-equilibrium molecular dynamics simulations in tandem with gas transport studies disclose that the defects in MOFs provide the MMMs with ultrafast transport pathways mainly governed by diffusivity selectivity. Ultimately, MMMs containing the most defective UiO-66 show the most enhanced CO2/N2 separation performance—CO2 permeability = 470 Barrer (four times higher than pure PEGDA) and maintains CO2/N2 selectivity = 41—which overcomes the trade-off limitation in pure polymers. The results emphasize that defect engineering in MOFs would mark a new milestone for the future development of optimized MMMs. 相似文献
69.
70.
A new voltage-programmed driving scheme named the mixed parallel addressing scheme is presented for AMOLED displays, in which one compensation interval can be divided into the first compensation frame and the consequent N-1 post-compensation frames without periods of initialization and threshold voltage detection. The proposed driving scheme has the advantages of both high speed and low driving power due to the mixture of the pipeline technology and the threshold voltage one-time detection technology. Corresponding to the proposed driving scheme, we also propose a new voltage-programmed compensation pixel circuit, which consists of five TFTs and two capacitors(5T2C). In-Zn-O thin-film transistors(IZO TFTs) are used to build the proposed 5T2C pixel circuit. It is shown that the non-uniformity of the proposed pixel circuit is considerably reduced compared with that of the conventional 2T1C pixel circuit. The number of frames(N) preserved in the proposed driving scheme are measured and can be up to 35 with the variation of the OLED current remaining in an acceptable range. Moreover, the proposed voltage-programmed driving scheme can be more valuable for an AMOLED display with high resolution, and may also be applied to other compensation pixel circuits. 相似文献