神东矿区8m以上超大采高综采工作面技术探讨

在结合上湾矿新开四盘区12401首采面地质条件的基础上,对超大采高综采工作面参数和产量进行了分析,计算了该工作面的支护强度要在1.6 MPa以上,护帮范围需要达到4.5 m以上,最后对8 m以上超大采高综采工作面主要综采设备的关键技术难点与可行性进行了分析,论证了8 m以上超大采高综采实现的可能。     

PLC在全自动太阳能制绒清洗设备中的应用

随着太阳能行业的高速发展,设备的自动化已成为太阳能硅片清洗设备的发展趋势。以全自动太阳能制绒清洗设备工艺流程为基础,介绍了欧姆龙PLC在全自动硅片清洗设备中的应用过程。     

Comparative Exploration of Document Collections: a Visual Analytics Approach

We present an analysis and visualization method for computing what distinguishes a given document collection from others. We determine topics that discriminate a subset of collections from the remaining ones by applying probabilistic topic modeling and subsequently approximating the two relevant criteria distinctiveness and characteristicness algorithmically through a set of heuristics. Furthermore, we suggest a novel visualization method called DiTop‐View, in which topics are represented by glyphs (topic coins) that are arranged on a 2D plane. Topic coins are designed to encode all information necessary for performing comparative analyses such as the class membership of a topic, its most probable terms and the discriminative relations. We evaluate our topic analysis using statistical measures and a small user experiment and present an expert case study with researchers from political sciences analyzing two real‐world datasets.     

μC/OS-II的应用设计

本文在研究TMS320LF2407结构及编程特点的基础上,详细讨论μC/OS-II的移植过程,主要分析移植中可能出现的问题,给出解决方法,并编写了一个应用软件来测试该系统移植的正确性。     

2 μm emission properties and hydroxy groups quenching of Tm3+ in germanate-tellurite glass

Tm³⁺ activated germanate-tellurite glasses with good thermal stability and anti-crystallization ability were prepared. Efficient 2 μm fluorescence was observed in the optimal concentration Tm³⁺ doped glass and the corresponding radiative properties were investigated. For Tm³⁺: ³F₄ → ³H₆ transition, high spontaneous radiative transition probability (260.75 s⁻¹) and large emission cross section (7.66 × 10⁻²¹ cm²) were obtained from the prepared glass. According to Dexter's and Forster's theory, energy transfer microscopic parameters were computed to elucidate the observed 2 μm emissions in detail. Besides, the effect of hydroxy groups quenching was also quantificationally investigated based on simplified rate equations. Results demonstrate that the optimal concentration Tm³⁺ doped germanate-tellurite glass possessing excellent spectroscopic properties might be an attractive candidate for 2 μm laser or amplifier.     

Potential barrier study at the InGaAs/InAs quantum dot interface in asymmetric multi quantum well structures

The photoluminescence and its temperature dependences have been investigated for the InAs quantum dots embedded in the asymmetric GaAs/In_xGa_1−xAs/In_0.15Ga_0.85As/GaAs quantum wells (dot-in-a-well, DWELL structures) as a function of the In content x (x = 0.10-0.25) in the capping In_xGa_1−xAs layer. The study of PL temperature dependences in the range of 80-120 K has revealed the potential barrier for electrons at the capping In_xGa_1−xAs/InAs QD interface. The value of mentioned barrier has varied in QD structures with the different In_xGa_1−xAs capping layer compositions and it was estimated in the studied asymmetric GaAs/In_xGa_1−xAs/In_0.15Ga_0.85As/GaAs DWELL structures. It is shown that the barrier for electrons equal to 48 and 24 meV appears in the InGaAs conduction band at the formation of InGaAs QW/InAs QD interface for the In compositions of x = 0.10 and 0.15, respectively. This barrier has not been detected in DWELLs with the In compositions x = 0.20 and 0.25. The energy gap offsets at the InAs/In_xGa_1−xAs interface in studied structures has been estimated and discussed as well.     

Light emission at 2 μm from Ho-Tm-Yb doped silicate glasses

The 2.0 μm emission properties and thermal stability of Yb-Tm-Ho triply-doped silicate glass are investigated. The characteristic temperatures, absorption spectrum and fluorescence spectra of the glasses are measured. Intensive emission near 2.0 μm is observed upon excitation at 980 nm and the corresponding mechanisms are discussed. Based on the measured absorption spectra, the absorption and emission cross sections, the Judd-Ofelt parameters and radiative properties are calculated and discussed. The predicted spontaneous transition probability for Ho³⁺:⁵I₇ → ⁵I₈ transition in silicate glass is 58.05 s⁻¹. The results indicate that the energy transfer in Yb³⁺ → Tm³⁺, Yb³⁺ → Ho³⁺, Tm³⁺ → Ho³⁺ is efficient and the Yb-Tm-Ho triply-doped silicate glass is a promising 2.0 μm laser glass material.     

TC6钛合金的超塑变形机制研究

提出了一种全新的超塑性研究方法：基于m值的高效超塑变形机制。采用该方法对TC6钛合金进行高温拉伸实验,研究其超塑性能,并与最大m值法超塑性进行比较分析。实验结果表明,细晶组织的该合金具有优良的超塑性,最佳变形温度在900℃,最大m值超塑变形可以获得20倍的最大延伸率;基于m值的高效超塑变形可以显著提高超塑成形效率,在获...     

抽水地面沉降中含水层长期变形特性研究

 长江三角洲地面沉降监测数据表明,抽水地面沉降中含水层的变形在总沉降量中占较大比例,且随时间长期发展。分析认为含水层砂土的蠕变是造成其变形长期发展的主要原因,而目前计算砂土蠕变特性的模型中普遍存在参数较多且确定困难的问题。根据含水层砂土的蠕变特性,对采用Singh黏性土蠕变模型计算含水层长期变形的方法进行研究。该模型假定土的蠕变速率与时间在双对数坐标系中呈线性关系,模型中仅有1个参数,即双对数坐标系中蠕变速率与时间曲线的斜率m。砂性土蠕变试验数据统计结果表明,砂性土的m值为0.9～1.1。通过对m的灵敏性分析可知,m在0.9～1.1区间内取值对计算结果影响不大,因此,在缺乏试验数据时可假定m = 1。利用常州和上海的地面沉降实测数据验证Singh模型计算含水层变形的有效性及模型参数简化确定方法的准确性。