Gateside packwall design in solid backfill mining-A case study

Based upon characteristic movement features of the overlying strata in solid backfill mining and in-situ observations,an associated model representing a roadway support system has been developed.Based on the Winkler foundation and beam model,the current study presents a static analysis of the model,thus permitting acquisition of a theoretical formula pertaining to roof convergence.Through use of working face 6304-1(Jisan Colliery) as the research setting,the association between roof convergence magnitude and both packwall strength and width have been elucidated.Based upon observed conditions at the working face,realistic packwall parameters have been formulated,with numerical simulation results and field application results indicating that design parameters garnered from the developed formula successfully adapted to local geological movement and deformation.Accordingly,roadway deformation was shown to be within the permissible range,thus satisfying mine production requirements.The proposed method in the current study may give a design basis for pack design in the context of SBM under similar conditions.     

室内低压电力线1～30MHz频段信道特性

国外电力线信道模型参数不适配于我国工程环境。实验测试了室内常用的截面积为2.5mm2硬铜线在1~30 MHz频带内的信道特性。固定频率时,考察导线长度变化对信道特性影响;固定长度时,考察频率变化对信道特性的影响。此外还观测了PVC材料、导线间距和导线距地面高度对信道特性的影响。根据实测数据,计算出了适用于我国环境的信道模型参数。通过与实测数据对比验证了仿真方法与所得参数的正确性。     

南极磷虾油对负重游泳小鼠的抗疲劳作用

为研究南极磷虾油对小鼠的抗疲劳作用,分别将高、中、低剂量全脂型虾油(WKO)和磷脂型虾油(PKO)每日1次灌入昆明种小鼠胃中,持续4周后,测定小鼠的负重游泳时间、肝糖原、肌糖原、血清乳酸。结果表明,中剂量WKO及PKO组小鼠的负重游泳时间均极显著长于空白对照组,低剂量PKO组小鼠的负重游泳时间显著长于空白对照组;3个剂量WKO组及高剂量PKO组的肝糖原水平极显著高于空白组;除低剂量PKO组外,其余虾油组小鼠的肌糖原水平极显著高于空白对照组小鼠,而血清乳酸水平均极显著低于空白对照组小鼠。     

基围虾冻藏过程中的品质变化

通过测定基围虾不同冻藏时间点(0、1、3、5、7周)质构、多酚氧化酶(PPO)活性、脂肪氧化、脂肪酸组成、风味及鲜度的变化,探究了对虾冻藏过程中品质变化的机理。结果表明,随着冻藏时间的延长,基围虾的黏附性逐渐增加,弹性、硬度、咀嚼性显著下降。PPO活性呈现先升后降的趋势。基围虾冻藏过程中脂肪氧化水平(TBARS)不断增加,饱和脂肪酸显著增加,多不饱和脂肪酸(PUFA)显著降低。基围虾冻藏过程中共检测出50多种挥发性风味物质,其中醇类和芳香族化合物含量降低,醛、酮及含氮化合物的含量增加。由ATP、ADP、AMP和HxR及Hx等鲜度指标的测定结果可知,基围虾冻藏7周后仍比较新鲜。虽然基围虾在冻藏过程中品质和营养价值降低,但仍较新鲜。     

Full color white light,temperature self-monitor,and thermochromatic effect of Cu+ and Tm3+ codoped germanate glasses

Lighting sources with full-color visible output are widely preferred in practical applications. In addition, modern lighting sources also tend to be intelligentized, and the intelligentization asks for smart luminescence materials. In this work, we attempt to develop novel full-color emitting material with temperature sensing and thermochromatic ability. To this end, the Cu²⁺ is successfully reduced to Cu⁺ which is incorporated into the germanate glasses. The glasses are prepared via a melt-quenching technique using graphite powders as reducing reagent. The supper-broadening of the excitation and the emission spectra of Cu⁺ in the germanate glasses are observed. Full-color emission is realized by introducing Tm³⁺ as co-dopant to provide the blue component in the spectra. The energy transfer behavior between Cu⁺ and Tm³⁺ is investigated, and it is found that these two luminescence centers are independently existent without energy transfer between them. The chromatic properties of the Cu⁺/Tm³⁺ co-doped glasses are tuned by Tm³⁺ concentration and excitation wavelength. The temperature sensing based on the fluorescence intensity ratio technique is demonstrated, and a constant sensitivity for the temperature detection is obtained. Moreover the thermochromatic property is also investigated, and it is found that the studied Cu⁺/Tm³⁺-doped glasses exhibit excellent thermochromatic performance.     

Study on performance characteristics of fused deposition modeling 3D-printed composites by blending and lamination

Component contacting degree in a composite material is an important reference for evaluation the performance characteristics. In this article, two composite material systems involving polylactic acid (PLA) with acrylonitrile butadiene styrene (ABS) and PLA with thermoplastic polyurethane (TPU) were prepared by blending and laminating through fused deposition modeling (FDM) 3D printing technology. The mechanical and thermal properties of the as-prepared composite materials were examined. The results indicated that PLA and TPU played a dominant role in tensile strength and breaking elongation, respectively, in individual composite material. ABS and TPU changed the glass transition peek, crystallinity, and modulus of PLA. The results also suggested that although the processing design of the blending method was more suitable for the contact between two components, but the mechanical properties of laminated composites were closer to theoretical predictions. The structural design and processing technology provide a comparative method and reference basis for studying the performance characteristics of composite materials.     

Polyethylene glycol modified epoxy acrylate UV curable 3D printing materials

The purpose of this paper is to research improvement in the flexibility of epoxy acrylate 3D printing materials so as to satisfy the requirements of clothing attachments or accessories. Tensile tests, differential scanning calorimeter, XRD, rheological and Fourier transform infrared analysis were used to measure and compare the performance and characteristics of polyethylene glycol modified bisphenol-A epoxy acrylate 3D printed samples with different molecular weights and contents. Based on a comprehensive analysis of the experimental results, the E/PEG₁₀₀₀(1/0.2)-AA sample was revealed to have an optimal composition ratio. After secondary curing, the tensile strength of the sample rose to 8 MPa, with the elongation being converged to 30%. This paper provides a reference for the modification and improvement of flexible UV-cured 3D printed products.     

Influence of forming method of blending versus casting layer-by-layer on structural properties and packing performances of casein-gelatin composite edible film under different appending proportion

In order to obtain casein edible films with great packing performance, gelatin as the reinforcing additive with different ratios were loaded via two methods including layer- by- layer and blending. A comparative study on structure properties between double layers and blending films made from casein and gelatin was obtained by scanning electron microscopy and Fourier transform infrared spectroscopy. The difference between the films' packing characters were conducted by water vapor permeability (WVP), optical property, and mechanical properties (including tensile strength (TS) and elongation (EAB)). The results showed that the degree of films roughness increased and the structural stability decreased as the increase of gelatin additive ratio in both double layers and blending films. Thickness and WVP both displayed a trend of increasing first then decreasing at the dividing of gelatin instead of casein in 50%. Importantly, WVP values in double layers film with a largest value of 6.95 gm⁻¹Pa⁻¹s⁻¹ was higher than blending films, observably (P < 0.05). Additionally, TS in blending film was increased by 23.44% than double layers film under the gelatin additive proportion of 70%, and EAB value in double layers film was larger by 207.65% than blending film under the gelatin additive proportion of 10%.     

Strong Convergence Analysis of Batch Gradient-Based Learning Algorithm for Training Pi-Sigma Network Based on TSK Fuzzy Models

By combining of the benefits of high-order network and TSK (Tagaki-Sugeno-Kang) inference system, Pi-Sigma network is capable to dispose with the nonlinear problems much more effectively, which means it has a compacter construction, and quicker computational speed. The aim of this paper is to present a gradient-based learning method for Pi-Sigma network to train TSK fuzzy inference system. Moreover, some strong convergence results are established based on the weak convergence outcomes, which indicates that the sequence of weighted fuzzy parameters gets to a fixed point. Simulation results show the modified learning algorithm is effective to support the theoretical results.     

A <Emphasis Type="Italic">K</Emphasis> self-adaptive SDN controller placement for wide area networks

As a novel architecture, software-defined networking (SDN) is viewed as the key technology of future networking. The core idea of SDN is to decouple the control plane and the data plane, enabling centralized, flexible, and programmable network control. Although local area networks like data center networks have benefited from SDN, it is still a problem to deploy SDN in wide area networks (WANs) or large-scale networks. Existing works show that multiple controllers are required in WANs with each covering one small SDN domain. However, the problems of SDN domain partition and controller placement should be further addressed. Therefore, we propose the spectral clustering based partition and placement algorithms, by which we can partition a large network into several small SDN domains efficiently and effectively. In our algorithms, the matrix perturbation theory and eigengap are used to discover the stability of SDN domains and decide the optimal number of SDN domains automatically. To evaluate our algorithms, we develop a new experimental framework with the Internet2 topology and other available WAN topologies. The results show the effectiveness of our algorithm for the SDN domain partition and controller placement problems.