自立式高耸结构风振控制方法研究

本文针对自立式高耸结构的风振控制装置及其设计方法开展研究。首先,根据自立式高耸结构的特点,设计了环形TMD、TLD和TLCD三种调频减振装置,并推导了其力学模型;随后,基于等效阻尼比的概念和我国规范的抗风设计方法,建立了自立式高耸结构风振控制的统一设计方法;最后,针对数值算例,进行了风振控制装置设计,并通过时程分析方法验证了该方法的有效性。研究结果表明,所设计的三种环形调频减振装置适用于自立式高耸结构的风振控制,建立的简化设计方法与时程分析的结果平均误差仅为5.37%,具有较高的精度,可用于自立式高耸结构的风振控制设计。     

傲牛铁矿三采区充填体稳定性及间柱回采顺序研究

随着傲牛铁矿三采区矿柱的回采,矿房充填体失去矿柱的侧压限制且暴露面积越来越大,充填体的受力条件发生改变,影响其稳定性,为此需要进行充填体的稳定性及回采顺序优化研究。结合傲牛铁矿的矿岩物理力学性质和矿柱回采方法,对矿房充填体建立力学模型,分析充填体在开采时受力的稳定性,计算充填体的极限自立高度;同时根据现场情况,提出了2种间柱整体开采顺序方案和2种中段间柱回采顺序方案,并对其进行了数值计算分析。计算结果表明:在整体开采间柱顺序上,从下至上开采最优,应力集中程度低,安全性高;在265 m中段间柱开采顺序上,先开采(1)、(3)、(5)间柱,再回采(2)、(4)间柱,位移变化较小。研究成果为现场的间柱回采提供了理论依据。     

安庆铜矿高阶段回采充填体-矿体-岩体稳定性的有限元分析

对安庆铜矿高阶段大直径深孔崩矿的１２０ｍ高充填体自立高度的稳定性进行分析后,着重用弹塑性有限元计算了采场的整体稳定性,其结果与现场实测数据比较符合。     

Self-standing flexible cathode of V2O5 nanobelts with high cycling stability for lithium-ion batteries

Self-standing V₂O₅ nanobelt electrode free of binders, conductive carbon or current collectors was successfully prepared via a simple one-step hydrothermal reaction. The length of V₂O₅ nanobelts was up to several hundreds micrometers and the thickness was around 40 nm. Ultralong nanobelts as building blocks and internal voids provide a robust mechanical flexibility and shortened ion/electron transport pathway. The self-standing electrode delivered an initial specific capacity of 127.4 mA h g⁻¹ at a current density of 60 mA g⁻¹ and exhibited excellent cycling stability with capacity retention up to 89.8% after 200 cycles. The outstanding cycling performance can be attributed to the excellent network stability, shortened Li-ion diffusion pathway and the high surface area between electrolyte/electrode interfaces.     

Influence of coexistent salt on hydrothermal synthesis of smectite and film-formability of the smectite

To evaluate the influence of coexistent salt in the Mg–Si precursor for the hydrothermal synthesis of smectite, stevensite was synthesized hydrothermally from Mg–Si precursors with different salt concentrations. Prepared homogeneous Mg–Si precursors were washed with distilled water before hydrothermal treatment. The salt concentration of the Mg–Si precursors was differentiated according to the washing cycle number. The salt concentration decreased concomitantly with increased washing cycles. Prepared smectite samples were characterized using ICP, XRD, TG-DTA, TEM, EDX, and viscosity measurement. Trioctahedral smectite peaks were observed in the XRD charts of all samples; NaNO₃ peaks were observed in the sample with excess salt. Excessive salt interrupted smectite synthesis, whereas salt of twice of ideal composition accelerated the smectite synthesis. Results also show that salt concentration affects smectite crystallinity. To investigate film formability of the derived smectite samples, coating films on glass substrates and binder-free self-standing films were prepared from aqueous dispersions of the derived smectite samples. The film formability improved with decreasing salt concentration of smectite. Smectite with low salt concentration forms a highly transparent film. Film formation processes were discussed through observation of film preparation using clay dispersions with different salt concentrations.     

Hierarchical Li4Ti5O12 nanosheet arrays anchoring on carbon fiber cloth as ultra-stable free-standing anode of Li-ion battery

A flexible, free-standing composite anode with Li₄Ti₅O₁₂ nanosheet arrays anchoring on plain-weaved carbon fiber cloth (LTO@CC) is prepared by a hydrothermal and post-annealing process assisted by a TiO₂ seed layer. The LTO@CC anode free from polymeric binder and conducting agent exhibited much higher lithium storage capacity and cycling stability than the conventional slurry-processed electrode using the dandelion-like Li₄Ti₅O₁₂ microspheres prepared by the same hydrothermal process. A high specific capacity of 128.8 mA h g^?1 was obtained at a current rate of 30 C (1 C = 175 mA g^?1), and almost negligible capacity loses was observed when the cell was cycled at 10, 20 and 30 C each for 100 cycles. The carbon fiber matrix contributed to Li storage at low current rate, but the LTO nanosheet arrays have played the dominant role on the excellent rate capability. The improved electrochemical performance can be attributed to the synergetic effect between the hierarchical Li₄Ti₅O₁₂ nanosheet arrays and the carbon fiber matrix, which integrated short Li⁺ diffusion length, three-dimensional conductive architecture and well preserved structural integrity during the high rate and repeated charge-discharge measurements.     

高阶段采场充填体强度及稳定性研究

从胶结充填体在采空区所起的力学作用入手,借助于经验类比法和数学力学模型计算法,得出了能够满足井下采空区所需的胶结充填体强度的要求,为矿山充填配比设计提供了强度依据。同时也分析了暴露宽度与暴露高度对胶结充填体强度的影响关系,揭示具有稳定性的胶结充填体力学强度变化特性。结合安徽某铜矿的工业性试验情况进行了实例分析,从而验证了上述结论的合理性。     

Self-standing and efficient bifunctional electrocatalyst for overall water splitting under alkaline media enabled by Mo1-xCoxS2 nanosheets anchored on carbon fiber paper

The layered MoS₂ nanostructures have been widely used in the electrochemical hydrogen evolution reaction (HER), but rarely applied in overall water splitting application for their ignorable oxygen evolution reaction (OER) activity. To address this issue, a novel self-standing and bifunctional electrocatalyst, consisting of Co-doped MoS₂ nanosheets anchored on carbon fiber paper, has been prepared via hydrothermal method. Taking advantage of conductive substrate of carbon fiber paper, sufficient-exposed active edges of MoS₂ sheets, and metallic character caused by Co-doping, our electrode exhibits high-efficient bifunctional activities for the overall water splitting in alkaline electrolyte (1 M KOH), which can produce a current density of 20 mA cm⁻² at an overpotential of 197 mV for HER and 235 mV for OER.     

SnSe nanoplates swallowed in carbon nanofibers as the self-standing anode for lithium-ion and sodium batteries with enhanced performance

SnSe is a promising anode candidate for both lithium-ion and sodium batteries (LIBs and SIBs) with high theoretic capacities, low toxicity and abundant resources. However, it suffers a short cycling life due to the poor conductivity and volume expansion when used as anode material. To improve its Li/Na storage properties, SnSe nanoplates are encapsulated in carbon nanofibers formation a 3D conductive network via a moderate electrostatic spinning and heat treatment. The modified SnSe anode exhibits textile-like feature with extensively mechanical flexibility, and was directly used as anode without and additives for both LIBs and SIBs. It delivers an excellent cycle performance with a high capacity (598 mA h g^?1 after 400 cycles for LIBs and 240 mA h g^?1 after 250 cycles for SIBs), which are modify enhanced comparing with reported works. The effective strategy can provide an available approach to build self-standing and flexible architecture, which is beneficial for the design of electrode materials for SIBs.