Microstructure and electric properties of Pr-doped Pb(Zr0.52Ti0.48)O3 ceramics

Improving the piezoelectric activity of lead zirconate titanate (PZT) ceramics is of great importance for practical applications. In this study, the influence of Pr³⁺ doping on the ferroelectric phase composition, microstructure, and electric properties on the A-site of (Pb_1-1.5xPr_x)(Zr_0.52Ti_0.48)O₃ is extensively investigated. A dense and fine microstructural sample is obtained with the introduction of Pr³⁺. The results show that the morphotropic phase boundary (MPB) moves to the rhombohedral phase region. The rhombohedral and tetragonal phases exhibit an ideal coexistence in the 4 mol.% Pr³⁺ doped (PPZT4) samples. Lead vacancy and the reduction of the potential energy barrier are considered to be the key mechanisms for donor doping, which is upheld by the Pr³⁺ doping. Combining the I-E hysteresis loops with the P-E hysteresis loops, it becomes apparent that both contribution maximums of the domain switching and residual polarisation are in PPZT4. Moreover, the thermal aging resistance of PZT is improved by doping, and the temperature stability is optimised from 83% in PZT to 96% in PPZT4. Hence, an appropriate amount of Pr³⁺ doping can effectively improve the piezoelectric activity of PZT ceramics in the MPB area and optimise the performance stability of the material under application temperatures.     

Cross-linked polyvinyl amidoxime fiber: a highly selective and recyclable adsorbent of gallium from Bayer liquor

Gallium, a scarce metal produced mainly from Bayer liquor, is widely used in semiconductors. Ion-exchange method is currently considered as the most effective method to recover gallium from Bayer liquor. In this article, fibrous amidoxime adsorbents are introduced to recover gallium from Bayer liquor. In addition, hydrazine cross-linked polyvinyl amidoxime (HPAO) fibers have been prepared. The structure of the as-prepared fibers was ascertained by FTIR, elemental analysis and weight gain rate. The adsorption kinetics, adsorption isotherm and recycling performance were investigated by batch method. Cross-linking duration was studied and it turned out to be an important factor to optimize the adsorption capacity and recycling performance. After 1.5 h cross-linking time, the fiber showed the highest gallium adsorption capacity of 14.83 mg/g in Bayer liquor. After 3 h cross-linking time, the fiber showed the best recycling performance, which retained 82.9% of the initial adsorption ability after four cycles. Adsorption capacity of vanadium was lower than 1 mg/g for all samples. HPAO displayed very fast adsorption kinetics with an equilibrium at 60 min. The EDS results confirmed the low extraction of aluminum and vanadium provided by HPAO fibers. The gallium-loaded fiber could be effectively eluted by acidified thiourea. With proper control of the cross-linking duration by hydrazine, HPAO fiber with high selectivity towards gallium, high adsorption capacity and good recycle performance could be obtained, which is promising for recovering gallium needed for industrial applications.     

安家岭储煤场输煤暗道通风除尘技术应用研究

针对输煤暗道的生产工艺现状，提出了采用通风与密闭抽尘净化技术，结合转载落料点密闭干雾降尘等技术措施，实现了输煤暗道内粉尘的的综合治理，通过粉尘浓度在线监测系统进行智能化控制，实现对输煤暗道通风除尘系统的远程连续监测监控，输煤暗道转载点下风侧5 m作业人员通行的位置总粉尘浓度由380.8 mg/m3降至19.8 mg/m3，降尘效率达94.8%，呼吸性粉尘浓度从96.7 mg/m3降至8.4 mg/m3，降尘效率达91.3%，降尘效果较好，有效地解决了输煤暗道及其转载落料点的粉尘污染问题，为输煤暗道内的粉尘防治提供参考依据。     

不同水头与流量条件下堤防梯形决口水流特性数值模拟

本文对有矩形障碍物的溃坝算例进行模拟验证,将FLOW-3D计算的速度场结果与FLUENT、Wang的结果进行对比,三者结果基本一致,验证了Flow-3D软件用于堤防决口三维数值模拟的可行性.采用某实际河道堤防简化建模,建立了在决口口门形状、尺寸一定的条件下,上游不同水头、不同流量工况下的堤防决口三维数值模拟.分析结果表明:不同水头、不同流量作用下决口较大的流速平面分布主要分布在决口上游进口左侧发生水跌处.因此,在进行决口封堵时,应注意预先做好决口上游侧的裹头处理,防止在封堵的过程中因流速过大导致溃口口门扩宽;在选取封堵材料时,也可根据溃口处流速分布来选择相应的封堵料粒径.     

Effect of neodymium substitution on crystalline orientation,microstructure and electric properties of sol-gel derived PZT thin films

Pb(Nd_xZr_0.52Ti_0.48)O₃ (PNZT) (x = 0%, 1%, 2%, 3%, 4%, 5%) thin films were prepared by sol-gel process to investigate the effects of neodymium substitution on crystalline orientation, microstructure and electric properties of lead zirconate titanate (PZT) films. X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis showed that PNZT films with Nd doping concentration below 3% exhibited dense perovskite structure with (100) preferred orientation. The average grain size of PNZT films decreased as the Nd substitution increased. The maximum dielectric constant, remnant polarization and minimum coercive field were obtained in 2% Nd-doped PZT films. Fatigue resistance was also improved significantly with 2% Nd dopant.     

Window Detection in Facades Using Heatmap Fusion

Journal of Computer Science and Technology - Window detection is a key component in many graphics and vision applications related to 3D city modeling and scene visualization. We present a novel...     

Effect of comb-type copolymer on crystallization of paraffin from waxy oils and methyl ethyl ketone (MEK) -toluene dewaxing

In this research, maleic anhydride-α-octadecene copolymer and its derivative with phenylethylamine was synthesized and its effect on the crystallization of paraffins was investigated. This derivative, when added into second cut of vacuum gas oil and forth cut of vacuum gas oil, increases the size and improves aggregation of paraffin crystals observed by polarizing light microscopy, increases onset temperature and enthalpy of paraffin crystallization determined by differential scanning calorimetry, improves the dewaxing efficiency with dosage of 100?ppm explored by MEK-toluene dewaxing.     

Super-Resolution Reconstruction of Images Based on Microarray Camera

In the field of images and imaging, super-resolution (SR) reconstruction of images is a technique that converts one or more low-resolution (LR) images into a highresolution (HR) image. The classical two types of SR methods are mainly based on applying a single image or multiple images captured by a single camera. Microarray camera has the characteristics of small size, multi views, and the possibility of applying to portable devices. It has become a research hotspot in image processing. In this paper, we propose a SR reconstruction of images based on a microarray camera for sharpening and registration processing of array images. The array images are interpolated to obtain a HR image initially followed by a convolution neural network (CNN) procedure for enhancement. The convolution layers of our convolution neural network are 3×3 or 1×1 layers, of which the 1×1 layers are used to improve the network performance particularly. A bottleneck structure is applied to reduce the parameter numbers of the nonlinear mapping and to improve the nonlinear capability of the whole network. Finally, we use a 3×3 deconvolution layer to significantly reduce the number of parameters compared to the deconvolution layer of FSRCNN-s. The experiments show that the proposed method can not only ameliorate effectively the texture quality of the target image based on the array images information, but also further enhance the quality of the initial high resolution image by the improved CNN.