冷轧退火对FeMnCoCrAl高熵合金组织和力学性能的影响

使用真空电弧炉熔炼出(Fe₅₀Mn₃₀Co₁₀Cr₁₀)₉₄Al₆合金,利用冷轧及在不同温度对合金进行退火,以期望得到由多尺度再结晶晶粒构成的层状结构;并对不同退火温度的样品进行拉伸性能测试。利用扫描电镜和EBSD对合金组织形貌进行表征,采用X射线衍射方法研究其相组成。结果表明:合金在铸态和冷轧后相组成未发生变化,700 ℃退火得到较好的多尺度再结晶晶粒的层状结构,其屈服强度为487 MPa,抗拉强度为708 MPa,断后伸长率为39%,表现出良好的综合力学性能。     

玉米秸秆衍生碳基固体酸的制备及其催化纤维素水解糖化

以玉米秸秆为原料，通过碳化-磺化法制备了碳基固体酸（CSA），采用XRD、FTIR、XPS、SEM、阳离子交换与返滴定法等手段对其结构形貌进行表征，并考察了制备条件对固体酸表面活性基团含量与催化活性的影响。以NaOH/尿素冻融预处理后的纤维素为底物，研究了CSA催化纤维素水解糖化的效果与条件。结果表明：NaOH/尿素冻融预处理能够有效辅助固体酸催化纤维素水解，在350℃碳化2h、100℃磺化5h条件下制备的CSA催化性能最好，其酸量达3.94mmol/g，其中磺酸基、羧基、酚羟基含量分别为1.09mmol/g、1.36mmol/g、1.49mmol/g。在m(CSA)∶m(纤维素)=3∶1、水解温度200℃、水解时间为0.5h的条件下，纤维素水解还原糖得率与转化率分别为47.1%和63%。CSA循环利用3次催化活性下降不大。本研究可为废弃生物质原料制备的固体酸催化纤维素水解转化利用提供科学参考。     

ACME台架蒸汽发生器传热特性数值模拟

以ACME台架的蒸汽发生器（SG）为研究对象，SG二次侧选用两流体模型，采用计算流体力学软件CFX对ACME台架的SG进行了整体直接模拟。针对稳定试验工况进行了计算，得到了SG一、二次侧的温度分布，二次侧空泡份额分布及传热管的壁温等参数沿U型管高度方向的变化，获得了二次侧较详细的流动和传热特性。计算结果表明，从第2道折流板开始，折流板底部已积聚了部分气泡，随高度的增加，折流板底部积聚的气泡越多，在弯管区附近及以上区域，已全部变为蒸汽。本文计算结果与试验结果符合较好。     

Transformation between nanosheets and nanowires structure in MnO2 upon providing Co2+ ions and applications for microwave absorption

The phase transition process of the MnO₂ phase with increases in Co²⁺ doping can be described by the Ouroboros symbol. The undoped sample is pure δ-MnO₂ with nanosheets structures. Then a small amount of Co²⁺ ions changes the final products and generates α-MnO₂ nanofibres in the δ-MnO₂ matrix. The products become pure α-MnO₂ with an appropriate amount of Co added. However, when the Co amount continues to increase, the amount of α-MnO₂ decreases in the products and turns back to form pure δ-MnO₂ in the end. Analysing the electromagnetic absorption performance, the relationship between the properties and the proportion of δ-MnO₂/α-MnO₂ in the powders adjusted by Co²⁺ doping has been explored, and the composites of δ-/α-MnO₂ show better absorption ability than the single-phase samples. As a result, the optimal reflection loss (RL) is −54.8 dB, and the effective absorption bandwidth can cover the Ku band at a thickness of 2.2 mm and the X band at a thickness of 3.1 mm with 50 wt.% filler loading ratios. This research might shed new light on the improvement of novel microwave absorption materials.

     

某铅锌矿的三维地质模型及储量估算

针对矿山现有的地质信息数据等，建立了以利用Surpac软件的三维地表模型、矿体模型及地质数据库，对矿山资源储量进行计算。基于地质统计学的理论，建立某铅锌矿地表模型、钻孔数据库、矿体模型、块体模型，对矿体内样品进行组合分析统计，采用幂次距离反比法对块体品位进行估值，最后根据国内对地质矿产资源的分类方法，按照不同边界品位、工业品位等分类依据，得出资源储量核实报告，为铅锌矿的后续生产，提供了可靠保证。结果表明：通过构建该矿地质数据库，建立的三维模型，可对地质工程、采矿工程、储量估算、矿石品位动态管理等提供技术支持。     

ZerNet: Convolutional Neural Networks on Arbitrary Surfaces Via Zernike Local Tangent Space Estimation

In this paper, we propose a novel formulation extending convolutional neural networks (CNN) to arbitrary two-dimensional manifolds using orthogonal basis functions called Zernike polynomials. In many areas, geometric features play a key role in understanding scientific trends and phenomena, where accurate numerical quantification of geometric features is critical. Recently, CNNs have demonstrated a substantial improvement in extracting and codifying geometric features. However, the progress is mostly centred around computer vision and its applications where an inherent grid-like data representation is naturally present. In contrast, many geometry processing problems deal with curved surfaces and the application of CNNs is not trivial due to the lack of canonical grid-like representation, the absence of globally consistent orientation and the incompatible local discretizations. In this paper, we show that the Zernike polynomials allow rigourous yet practical mathematical generalization of CNNs to arbitrary surfaces. We prove that the convolution of two functions can be represented as a simple dot product between Zernike coefficients and the rotation of a convolution kernel is essentially a set of 2 × 2 rotation matrices applied to the coefficients. The key contribution of this work is in such a computationally efficient but rigorous generalization of the major CNN building blocks.     

Study on the stability of gas film in electrochemical discharge machining of ultra-white glass micro array holes

With the widespread application of non-conducting tough materials, such as ultra-white glass in MEMS recent years, many difficulties have arisen in the processing of these kind of material with eigen-structure characteristics. By analyzing the generation principle of interelectrode gas film of this kind of material, the breakdown characteristics of gas film under different power supply parameters are studied, and the relationship between the process parameters and the forming quality, material removal rate under the condition of gas film stability is further analyzed, so as to realize the optimal selection and the ultra-white glass micro array holes successfully machined.

     

基于高速动态的颗粒气泡脱附过程动力学研究

通过颗粒气泡脱附高速动态测试系统，研究了颗粒气泡脱附过程动力学。运用Image-Pro Plus图像处理软件测量颗粒气泡间接触角、三相润湿周边，计算颗粒气泡间毛细黏附力随颗粒运动时间的变化。结果表明：颗粒从气泡表面脱附主要分为气泡拉伸变形接触角增大和气泡滑动三相润湿周边减小两个阶段。气泡拉伸阶段，三相润湿周边固定在颗粒表面，接触角由平衡接触角增大到前进接触角；气泡滑动阶段，接触角保持不变，三相润湿周边滑动减小。毛细黏附力在气泡脱附过程中随接触角增大而增大，随三相润湿周边滑动而减小，当外力超过颗粒气泡间临界黏附力时，颗粒从气泡表面脱附。     

Thermal-Disrupting Interface Mitigates Intercellular Cohesion Loss for Accurate Topical Antibacterial Therapy

Bacterial infections remain a leading threat to global health because of the misuse of antibiotics and the rise in drug-resistant pathogens. Although several strategies such as photothermal therapy and magneto-thermal therapy can suppress bacterial infections, excessive heat often damages host cells and lengthens the healing time. Here, a localized thermal managing strategy, thermal-disrupting interface induced mitigation (TRIM), is reported, to minimize intercellular cohesion loss for accurate antibacterial therapy. The TRIM dressing film is composed of alternative microscale arrangement of heat-responsive hydrogel regions and mechanical support regions, which enables the surface microtopography to have a significant effect on disrupting bacterial colonization upon infrared irradiation. The regulation of the interfacial contact to the attached skin confines the produced heat and minimizes the risk of skin damage during thermoablation. Quantitative mechanobiology studies demonstrate the TRIM dressing film with a critical dimension for surface features plays a critical role in maintaining intercellular cohesion of the epidermis during photothermal therapy. Finally, endowing wound dressing with the TRIM effect via in vivo studies in S. aureus infected mice demonstrates a promising strategy for mitigating the side effects of photothermal therapy against a wide spectrum of bacterial infections, promoting future biointerface design for antibacterial therapy.