The dimension split element-free Galerkin method for three-dimensional potential problems

This paper presents the dimension split element-free Galerkin （DSEFG） method for three-dimensional potential problems, and the corresponding formulae are obtained. The main idea of the DSEFG method is that a three-dimensional potential problem can be transformed into a series of two-dimensional problems. For these two-dimensional problems, the improved moving least-squares （IMLS） approximation is applied to construct the shape function, which uses an orthogonal function system with a weight function as the basis functions. The Galerkin weak form is applied to obtain a discretized system equation, and the penalty method is employed to impose the essential boundary condition. The finite difference method is selected in the splitting direction. For the purposes of demonstration, some selected numerical examples are solved using the DSEFG method. The convergence study and error analysis of the DSEFG method are presented. The numerical examples show that the DSEFG method has greater computational precision and computational efficiency than the IEFG method.

Estimation of Gibbs free energy difference in Pd-based bulk metallic glasses

A new thermodynamic expression for Gibbs free energy difference ΔG between the under-cooled liquid and the corresponding crystals of bulk metallic glasses was derived. The newly proposed expression always gives results in fairly good agreement with experimental values over entire temperature range between the fusion temperature Tm and the glass transition temperature Tg of Pd40Ni40P20, Pd40Cu30Ni10P20 and Pd43Cu27Ni10P20, which possess different heat capacities. However, the TS and KN expressions cannot always provide results in good agreement with the experimental values. In addition, the deviations between the experimental values and the ΔG calculated by the proposed expression at Tg are smaller than those given by other expressions for all the bulk metallic glasses studied.

基于白噪声分析理论的Spin Glasses能量模型

使用白噪声分析理论研究Spin Glasses随机能量模型,对Derrida极限定理进行了推广;在白噪声分析框架下,给出了基于指数映射的极限定理,并提出了白噪声分析框架下的随机模型.

A thermodynamic approach to assess glass-forming ability of bulk metallic glasses

According to the Gibbs free energy difference between liquid and crystal,a thermodynamic glass-forming ability(GFA) parameter related to characteristic temperatures,onset crystallization temperature(Tx)and liquidus temperature(Tl),was proposed for evaluating the GFA of bulk metallic glasses(BMGs).The new parameter defined asω=Tl(Tl+Tx)/(Tx(Tl-Tx))has good correlation with the critical section thickness(Zc)of Ca-Mg-Cu BMGs.Being verified by the glasses data,including oxide glasses,which were used to validate the former GFA parameters,ωis one of the most reliable and applicable GFA parameters among Trg(=Tg/Tl), γ(=Tx/(Tl+Tg)),α(=Tx/Tl),δ(=Tx/(Tl-Tg),and so on.Finally,predicting GFA of Cu-Ag-Zr-Ti and Cu-Zr-Ti-Al BMGs usingωwas compared with the experimental results.

Heavy metal free primers: Polymorphism of gadolinium and titanium in the context of GSR glass phase

The possibility of identifying gunshot residue (GSR) particles produced by non-toxic primers containing only titanium and zinc is a very difficult task using SEM/EDX analysis employed in the analysis of GSR originating from primers containing lead, barium and antimony. However, Bauer et al. demonstrated that non-toxic (TieZn) primers form a TiZn2O4 spinel crystalline structure using SEM/EDX with EBSD (Electron Back Scatter Diffraction) and TKD (Transmission Kikuchi Diffraction), whereas GSR originating from gadolinium-doped TieZn primers form a non-crystalline glass phase. Here, a possible explanation of these different phenomena is hypothesized.

Gibbs Free Energy and Activation Energy of ZrTiAlNiCuSn Bulk Glass Forming Alloys

The Gibbs free energy differences between the supercooled liquid and the crystalline mixture for the (Zr_(52.5)Ti_5Al_(10)-Ni_(14.6)Cu_(17.9))_((100-x)/100)Sn_x (x=0, 1, 2, 3, 4 and 5) glass forming alloys are estimated by introducing the equationproposed by Thompson, Spaepen and Turnbull. It can be seen that the Gibbs free energy differences decrease firstas the increases of Sn addition smaller than 3, then followed by a decrease due to the successive addition of Snlarger than 3, indicating that the thermal stabilities of these glass forming alloys increase first and then followed by adecrease owing to the excessive addition of Sn. Furthermore, the activation energy of Zr_(52.5)Ti_5Al_(10)Ni_(14.6)Cu_(17.9) and(Zr_(52.5)Ti_5Al_(10)Ni_(14.6)Cu_(17.9))_(0.97)Sn_3 was evaluated by Kissinger equation. It is noted that the Sn addition increases theactivation energies for glass transition and crystallization, implying that the higher thermal stability can be obtainedby appropriate addition of Sn.

ON THE DIMENSION OF THE DIVERGENCE SET OF THE OSTROVSKY EQUATION

We investigate the refined Carleson’s problem of the free Ostrovsky equation{ut+■_(z)^(3)u+■_(x)^(-1)u=0,u(x,0)=f(x)where(x,t)∈R×R and f∈H^(s)(R).We illustrate the Hausdorff dimension of the divergence set for the Ostrovsky equationα1,U(s)=1-2 s,1/4≤s≤1/2.

Corrosion of Basic Refractories for Glass Tanks Using Petrol Coke and Countermeasures

Replacing heavy oil with petrol coke can greatly reduce the cost of glass production,but obviously shorten the service life of refractories used in the regenerator checker body of glass tanks.To prolong the service life of the regenerator checker body,the slag chemical composition and alkali-sulfur ratio of glass tanks after using petrol coke and the damage mechanism of the residual magnesia bricks in the regenerator checker body were studied,as well as the corrosion resistance of three magnesia based bricks(direct bonded magnesia chrome bricks,fused rebonded magnesia chrome bricks,and fused rebonded high-purity magnesium aluminate spinel bricks).On this basis,a series of targeted countermeasures were adopted to optimize the configuration of refractories,significantly improving the service life of checker bricks and meeting the requirements of glass industry development.

Critical Finite Size Scaling Relation of the Order-Parameter Probability Distribution for the Three-Dimensional Ising Model on the Creutz Cellular Automaton

我们在周期的边界条件下面在简单立方的格子上为三维的 spin-1/2 和 spin-1 Ising 模型在批评的点学习顺序参数概率分发。为顺序参数概率分发放大关系的有限尺寸被微正规 Creutz 细胞的自动机模拟数字地测试并且验证。州的批评代表三角洲，描绘可伸缩的顺序参数概率分发的远尾巴政体，在批评温度用细胞的自动机模拟为三维的 Ising 模型被估计。结果在对蒙特卡罗计算的好同意。

基于电子平均自由程的金属纳米颗粒临界尺寸估算

基于金属价电子占据k空间体积与布里渊区体积之间的关系,求出费米球半径,导出电子平均自由程的计算公式。以Ag和Cu为例计算出电子平均自由程,与其他方法计算结果一致。当金属材料的几何尺度与电子平均自由程相当时,与之相关的物理性能会发生显著变化,从这个角度出发,用电子平均自由程尺度估算Ag和Cu的纳米尺寸临界值分别为52 nm和39 nm。这种计算思路同样适用于其他金属纳米材料。

基于Google Glass解放双手遥控移动机器人系统

随着人机交互技术的发展,解放双手的技术日臻繁荣。在面对复杂任务时,解放双手的技术提供了新的交互渠道,丰富了交互信号的来源。利用Google Glass穿戴式的特点,搭建了一个解放双手的移动机器人远程控制系统。本系统使用旋转矢量传感器检测操作者的头部运动,设计控制器解析操作者的控制意图,并经WI-FI发送给机器人。为了验证系统的灵活性和可靠性,对其进行避障实验测试。实验结果表明,操作者使用该系统能够流畅地控制机器人完成任务,成功地从任务中解放出双手;同时,为遥控移动机器人提供了新的方式。

基于Google Glass的远程解放双手式机器人控制系统

随着人机交互技术的发展,解放双手的技术也日益繁荣。在面对复杂任务时,解放双手的技术提供了新的交互渠道,丰富了交互信号的来源。利用Google Glass穿戴式的特点,搭建了一个解放双手的移动机器人远程控制系统。该系统运用互补滤波器融合加速度传感器、陀螺仪以及地磁传感器的测量数据检测操作者的头部运动,并根据设计的控制器解析操作者的控制意图,然后经WiFi传送给被控机器人。同时,运用互补滤波器的高通滤波器成分成功地抑制了头部参考位置的漂移。为了验证系统的灵活性和可靠性,对其进行避障实验测试。实验结果表明,操作者能够流畅地控制机器人完成任务,成功地从任务中解放出双手,为遥控移动机器人提供了新的方式。此外,这一解放双手的系统对双手残疾者也大有益处。

脉冲激光焊接Zr基非晶合金晶化后纳米压痕行为

试验采用脉冲激光束将Zr基非晶合金与铝结合,研究焊接接头中非晶合金晶化后的纳米压痕变形行为。该文从自由体积与塑性变形能量耗散的角度详细分析了不同晶化相含量对变形行为的影响。焊接接头不同区域的微区X射线衍射研究表明,由于不同的冷却速率可形成3个不同的结晶度区域,焊缝由部分结晶区域(熔合区和热影响区)和非晶态区域(BMGs母材)组成,并且形成了Zr2Cu和Zr2Ni等硬质金属间化合物。该文讨论了压痕周围的锯齿状流动行为和堆积形态,验证了非晶合金中,自由体积越大的区域在纳米压痕过程中呈现出更明显的锯齿,结晶率最高的熔合区具有最高的纳米压痕硬度和约化弹性模量。在1600~3100μN压痕载荷范围内,纳米压痕中的塑性变形能耗随压痕载荷的增大而增大。

基于包容性设计理念智能导盲眼镜设计与探究

制定适合视障人士行为习惯的产品,并提出有关盲人群体的产品设计策略,建立产品、人和环境三者之间良好的互动关系。分析视障群体的需求层次,明确触觉体验在产品应用上的重要性,并在包容性设计理念的引领下,运用感官代偿方法来研究与实践,从而给出避障措施改善视障者出行体验。基于用户需求得出具体导盲方案,制作出三维模型、应用效果、伴护系统方案。针对性地提出有关盲人助行产品的解决方案,以触觉、听觉提高产品交互效率,为弱势群体思考的人性化设计提供一些借鉴与参考。

探究浸润剂对无碱玻璃纤维性能的影响及解决对策

本文深入探讨浸润剂在增强无碱玻璃纤维性能方面的关键作用,通过详细分析浸润剂对纤维的物理强度、化学稳定性和热性能的影响,旨在阐明科学选择和优化浸润剂的方法。本文涵盖了不同浸润剂的性质,并为它们在工业生产中的应用提供了明确的指导原则,此外还关注于配方的改进和生产过程的调整,目标是提升无碱玻璃纤维的整体性能,并同时考虑环境的影响,以促进可持续发展。通过这一综合性分析,本文为无碱玻璃纤维的发展提供了全面的理论和实践指导。

COMPUTER SIMULATION OF PHASE SEPARATION IN CaO-MgO-Fe_2O_3-Al_2O_3-SiO_2 GLASS

The fractal and spinodal decomposition models combined Monte Carlo method were used in computer simulation of phase separation from CaO MgO Fe 2O 3 Al 2O 3 SiO 2 glass. The fractal dimension was applied to quantitative analysis. The mechanism of phase separation was investigated. The results showed that the fractal dimensions and simulated micrographs of phase separation were in good agreement with the experimental results. And the mechanism of phase separation was spinodal decomposition.

Effects of Microalloying on Glass Forming Ability and Thermodynamic Fragility of Cu-Pr-Based Amorphous Alloys

The effects of microalloying of Ti and B on the glass formation of Cu60Pr30Ni10Al10-2xTixBx（x = 0, 0.05% （atom fraction）） amorphous alloys was investigated using differential scanning calorimetry （DSC） and X-ray diffraction （XRD）. XRD analysis showed that mieroalloying with 0.05% Ti and 0.05% B improved the glass forming ability （GFA）. The smaller difference in the Gibbs free energy between the liquid and crystalline states at the glass transition temperature （△G1-X（Tg）） and the smaller thermodynamic fragility index （△Sf/Tm, where ASf is the entropy of fusion, and Tm is the melting temperature） after mieroalloying correlated with the higher GFA.

Study on Glass Fiber Dispersion Technology in SiO_2 Aerogel-glass Fiber Composite Insulation Materials

In order to improve the mechanical properties of SiO_2 aerogel-glass fiber composites, effects of different solvents(cyclohexane, n-hexane, ethanol, acetone) and different dispersing modes(planetary ball milling, ultrasonic dispersion and mechanical stirring) and dispersing duration(10-40 min) on the dispersion of chopped alkali-free glass fiber bundles were studied to determine the best dispersion process. On this basis, the materials were batched according to the mass fraction of SiO_2 aerogel powder to chopped alkali free glass fiber bundles of 90:10, and a certain amount of zinc oxide light-screening agent and phenolic resin binder were added. SiO_2 aerogel glass fiber composite specimens were prepared by direct adding chopped alkali free glass fiber bundles and pre-dispersed chopped alkali free glass fiber bundles, respectively. The cold crushing strength and the thermal conductivity at different surface temperatures(300, 400, 500 and 600 ℃, respectively)of the specimens were measured. The results show that:(1) the optimum dispersion process of chopped alkali-free glass fiber bundles is using ethanol as solvent and mechanical stirring for 30 min;(2) pre-dispersion of chopped alkali-free glass fiber bundles has little effect on the thermal conductivity of SiO_2 aerogel-glass fiber composites but can improve the cold crushing strength.

Surface Characterization of Glass Fiber by Inverse Gas Chromatography

The surface properties of glass fiber were quantificationally analyzed by inverse gas chromatography （IGC）. Five n-alkanes （C6, C7, C8, C9, and C10） were chosen as apolar probes to characterize the dispersive component of surface free energy. Trichloromethane （CHCl3）, acetone, and tetrahydrofuran （THF） were chosen as polar probes to detect the Lewis acid-base parameters. It is found that the dispersive components of free energy are 32.3, 30.5, 27.5, and 26.9 mJ/m^2 at 70, 80, 90, and 100 ℃. respectively. The Lewis acidic number Ka of the glass fiber is 0.512 4, and the basic number Kb is 2.862. The results mean the glass fiber is a Lewis basic material.