面向过程装备工程师培养的O2O课程体系构建

过程装备与控制工程专业的人才培养方案及课程体系可以划分为线上和线下两块。线上课程侧重于新知识传授,有助于学生开阔眼界,活跃思维,启迪智慧;线下课程侧重于基本知识传授,有助于学生夯实专业基础,培养专业素养,锻炼工程技能。研究线上和线下课程的主辅关系及交互模式,形成具有鲜明流程工业装备特征的“线上+线下”一体化课程群,建立培养效果(达成度)的评价方法与持续改进机制,有利于培养掌握综合知识、善于设计计算、了解制造检验的优秀过程装备工程师。     

饱和尾粉砂动孔隙水压力发展特性试验研究

采用动三轴仪对内蒙古某尾矿库尾粉砂进行了动强度试验,研究了围压、相对密实度及固结比对动荷载作用下尾粉砂中孔隙水压力发展特性的影响。研究结果表明,随着固结比、相对密实度、围压的增大,动荷载作用下饱和尾粉砂孔压增长曲线形状由陡峭转变为平缓。随着围压及固结比增大,试样动力破坏形式从以孔压值为主要表征指标的液化破坏,转化为以动剪应变为主要破坏形式的软化破坏。动荷载作用下发生液化破坏的饱和尾粉砂孔压增长过程分可为初始增长阶段、稳定增长阶段和快速增长至破坏阶段,孔压增长曲线表现为明显的反S型,本文采用双对数函数对该试验孔压增长曲线进行拟合,结果表明该模型可以较好地模拟尾粉砂在动荷载作用下的孔压发展规律。     

孤岛工作面撤出支架时的顶板加固及撤出工艺

11210高水充填工作面作为孤岛工作面,末采阶段顶板压力大。采用锚网支护控制工作面顶板,撤架时利用掩护架保证撤架空间安全,利用移架平台撤出剩余支架,实现了安全生产。     

Matrix Transformation in Boron Containing High-Temperature Co–Re–Cr Alloys

An addition of boron largely increases the ductility in polycrystalline high-temperature Co–Re alloys. Therefore, the effect of boron on the alloy structural characteristics is of high importance for the stability of the matrix at operational temperatures. Volume fractions of ε (hexagonal close-packed—hcp), γ (face-centered cubic—fcc) and σ (Cr₂Re₃ type) phases were measured at ambient and high temperatures (up to 1500 °C) for a boron-containing Co–17Re–23Cr alloy using neutron diffraction. The matrix phase undergoes an allotropic transformation from ε to γ structure at high temperatures, similar to pure cobalt and to the previously investigated, more complex Co–17Re–23Cr–1.2Ta–2.6C alloy. It was determined in this study that the transformation temperature depends on the boron content (0–1000 wt. ppm). Nevertheless, the transformation temperature did not change monotonically with the increase in the boron content but reached a minimum at approximately 200 ppm of boron. A probable reason is the interplay between the amount of boron in the matrix and the amount of σ phase, which binds hcp-stabilizing elements (Cr and Re). Moreover, borides were identified in alloys with high boron content.     

YSZ/MoS2 self-lubricating coating fabricated by thermal spraying and hydrothermal reaction

Thermal sprayed ceramic coatings have extensively been used in components to protect them against friction and wear. However, the poor lubricating ability severely limits their application. Herein, yttria-stabilized zirconia (YSZ)/MoS₂ composite coatings were successfully fabricated on steel substrate with the combination of thermal spraying technology and hydrothermal reaction. Results show that the synthetic MoS₂ powders are composed of numbers of ultra-thin sheets (about 7 ~ 8?nm), and the sheet has obvious lamellar structure. After vacuum impregnation and hydrothermal reaction, numbers of MoS₂ powders, look like flowers, generate inside the plasma sprayed YSZ coating. Moreover, the growing point of the MoS₂ flower is the intrinsic micro-pores of YSZ coating. The friction and wear tests under high vacuum environment indicate that the composite coating has an extremely long lifetime (>?100,000 cycles) and possesses a low friction coefficient less than 0.1, which is lower by about 0.15 times than that of YSZ coating. Meanwhile, the composite shows an extremely low wear rate (2.30?×?10^?7 mm³ N^?1 m^?1) and causes slight wear damage to the counterpart. The excellent lubricant and wear-resistant ability are attributed to the formation of MoS₂ transfer films and the ultra-smooth of the worn surfaces of hybrid coatings.     

复合材料在旋转压缩机上的应用分析

文章介绍了目前旋转式压缩机主要零部件的材料状况,详细论述了金属基复合材料、陶瓷基复合材料在旋转压缩机上的应用情况及前景,为复合材料在压缩机领域的应用提供指导。     

Theoretical Prediction of Chiral 3D Hybrid Organic–Inorganic Perovskites

Hybrid organic–inorganic perovskites (HOIPs), in particular 3D HOIPs, have demonstrated remarkable properties, including ultralong charge‐carrier diffusion lengths, high dielectric constants, low trap densities, tunable absorption and emission wavelengths, strong spin–orbit coupling, and large Rashba splitting. These superior properties have generated intensive research interest in HOIPs for high‐performance optoelectronics and spintronics. Here, 3D hybrid organic–inorganic perovskites that implant chirality through introducing the chiral methylammonium cation are demonstrated. Based on structural optimization, phonon spectra, formation energy, and ab initio molecular dynamics simulations, it is found that the chirality of the chiral cations can be successfully transferred to the framework of 3D HOIPs, and the resulting 3D chiral HOIPs are both kinetically and thermodynamically stable. Combining chirality with the impressive optical, electrical, and spintronic properties of 3D perovskites, 3D chiral perovskites is of great interest in the fields of piezoelectricity, pyroelectricity, ferroelectricity, topological quantum engineering, circularly polarized optoelectronics, and spintronics.     

A novel method based on convolutional neural networks for deriving standard 12-lead ECG from serial 3-lead ECG

Frontiers of Information Technology & Electronic Engineering - Reconstruction of a 12-lead electrocardiogram (ECG) from a serial 3-lead ECG has been researched in the past to satisfy the need...     

Imaging of two-dimensional unsaturated moisture flows in uncracked and cracked cement-based materials using electrical capacitance tomography

The development of visualizing tools to monitor unsaturated moisture flow in cement-based materials is of great importance, as most degradation processes in cement-based materials are connected to and take place in the presence moisture. This paper investigates the ability of electrical capacitance tomography (ECT) to image two-dimensional (2D) unsaturated moisture flow in cement-based materials. In ECT, the electrical permittivity distribution within an object is reconstructed based on measured capacitances between electrodes attached on the object’s surface. In a series of experiments, mortar specimens with and without discrete cracks were imaged with ECT during a 2D moisture ingress. The results show that ECT is able to monitor the evolution of the moisture flow, and to approximate the shape and position of the moisture front. These findings indicate that ECT is a viable method for monitoring and visualizing 2D unsaturated moisture flow in cement-based materials in the presence and absence of discrete cracks.