用数值方法分析绝热毛细管的流量特性

根据均相流假设，用两相流基本方程建立了毛细管的数学模型，采用一种快速、有效的计算方法对绝热毛细管的流量特性进行数值模拟，并把计算结果与实验数据进行了对比分析。     

安钢"一罐到底"铁水供应模式运行实践

介绍了"一罐到底"铁水供应模式在安钢的运行实践。通过对设备的技术改造和生产组织的精益管理,较好地解决了"一罐到底"铁水供应模式中遇到的相关难题,保证了"一罐到底"模式的高执行率运行,使铁水入炉温度得到提升,铁水消耗大幅降低,取得了较好的经济效益。     

Kirigami‐Inspired Self‐Assembly of 3D Structures

Self‐assembly of 3D structures presents an attractive and scalable route to realize reconfigurable and functionally capable mesoscale devices without human intervention. A common approach for achieving this is to utilize stimuli‐responsive folding of hinged structures, which requires the integration of different materials and/or geometric arrangements along the hinges. It is demonstrated that the inclusion of Kirigami cuts in planar, hingeless bilayer thin sheets can be used to produce complex 3D shapes in an on‐demand manner. Nonlinear finite element models are developed to elucidate the mechanics of shape morphing in bilayer thin sheets and verify the predictions through swelling experiments of planar, millimeter‐scaled PDMS (polydimethylsiloxane) bilayers in organic solvents. Building upon the mechanistic understandings, The transformation of Kirigami‐cut simple bilayers into 3D shapes such as letters from the Roman alphabet (to make “ADVANCED FUNCTIONAL MATERIALS”) and open/closed polyhedral architectures is experimentally demonstrated. A possible application of the bilayers as tether‐less optical metamaterials with dynamically tunable light transmission and reflection behaviors is also shown. As the proposed mechanistic design principles could be applied to a variety of materials, this research broadly contributes toward the development of smart, tetherless, and reconfigurable multifunctional systems.     

Preparation and luminescence properties of Y<Subscript>3−y</Subscript>Al<Subscript>5−x</Subscript>Ga<Subscript>x</Subscript>O<Subscript>12</Subscript>:Ce<Superscript>3+</Superscript><Subscript>y</Subscript> phosphors

Y_3?yAl_5?xGa_xO₁₂:Ce³⁺_y phosphors were prepared by high temperature solid state reaction method. The crystal structures, the influence of Ga³⁺ concentration on the photoluminescence (PL), cathodoluminescence, thermal stability and morphology of the phosphors were studied in detail. The results indicated that diffraction angle of the samples decreased gradually with the increase of Ga³⁺ ions content in XRD pattern. The emission peak of the spectra show a progressive blue-shift, the intensity increased first and then decreased and the optimal Ga³⁺ concentration in Y_2.94Al_5?xGa_xO₁₂:Ce³⁺_0.06 phosphors is x?=?0.75. The critical concentration of Ce³⁺ in YAGG:Ce³⁺ phosphors is affected with the ratio of Ga³⁺ to Al³⁺ and the Y_2.9Al_4.25Ga_0.75O₁₂:Ce³⁺_0.1 phosphor showed the best performance on PL. However, the optimum concentration of Y_3?yAl_5?xGa_xO₁₂:Ce³⁺_y phosphors is x?=?1.5 and y?=?0.04 when they were excited by cathode ray.     

Modulation of Metal and Insulator States in 2D Ferromagnetic VS2 by van der Waals Interaction Engineering

2D transition‐metal dichalcogenides (TMDCs) are currently the key to the development of nanoelectronics. However, TMDCs are predominantly nonmagnetic, greatly hindering the advancement of their spintronic applications. Here, an experimental realization of intrinsic magnetic ordering in a pristine TMDC lattice is reported, bringing a new class of ferromagnetic semiconductors among TMDCs. Through van der Waals (vdW) interaction engineering of 2D vanadium disulfide (VS₂), dual regulation of spin properties and bandgap brings about intrinsic ferromagnetism along with a small bandgap, unravelling the decisive role of vdW gaps in determining the electronic states in 2D VS₂. An overall control of the electronic states of VS₂ is also demonstrated: bond‐enlarging triggering a metal‐to‐semiconductor electronic transition and bond‐compression inducing metallization in 2D VS₂. The pristine VS₂ lattice thus provides a new platform for precise manipulation of both charge and spin degrees of freedom in 2D TMDCs availing spintronic applications.     

Coronary Artery Fibrous Plaque Detection Based on Multi-Scale Convolutional Neural Networks

Journal of Signal Processing Systems - One of the major causes of the coronary heart disease is vascular stenosis and thrombosis that is generally caused by development of fibrous plaques....     

Inhibition of Polyunsaturated Fatty Acids Synthesis Decreases Growth Rate and Membrane Fluidity of <Emphasis Type="Italic">Rhodosporidium kratochvilovae</Emphasis> at Low Temperature

The intention of this study was to investigate the role of polyunsaturated fatty acids (PUFA) in the cold adaptation of Rhodosporidium kratochvilovae YM25235 by knockout of the Δ¹²/Δ¹⁵-fatty acid desaturase gene (RKD12) to inactivate Δ¹²/Δ¹⁵-fatty acid desaturase. Polymerase chain reaction (PCR) amplification was used to detect the genomic structure of RKD12 gene in YM25235. The RKD12 gene was knocked out by DNA homologous recombination to inhibit the biosynthesis of PUFA. Then, the contents of linoleic acid (LNA) and α-linolenic acid (ALA) after gene knockout were investigated using a gas chromatography-mass spectrometer, followed by determination of the growth rate and membrane fluidity of YM25235 at low temperature. After PCR amplification, a 1611 bp genomic fragment was amplified from YM25235. When the RKD12 gene was knocked out, the contents of LNA and ALA in YM25235 significantly decreased. The growth rate and membrane fluidity of YM25235 decreased significantly at low temperature. Inhibition of PUFA biosynthesis by RKD12 gene knockout influenced cold adaptation of YM25235 by decreasing the PUFA content in cell membranes and reducing the growth rate and membrane fluidity of YM25235 at low temperature.     

鼓泡破泡一体化高效精馏塔盘流动特性与CFD模拟

就痕量精馏中塔板传质效率低、需强化气液传质的问题,研究者提出了新型鼓泡破泡一体化高效精馏塔盘,通过在筛板上泡沫层高度范围内设置一层破泡装置,打破大气泡,减小气泡体积,强制界面进行更新,从而提高传质效率。采用双欧拉模型分别对鼓泡破泡一体化塔盘和筛板进行了气液流场的数值模拟,并对模型进行了验证。对比两种塔板的计算结果可以看出：在相同操作条件下,破泡装置将大气泡破裂成无数小气泡,使高气含率区域面积较普通筛板进一步增大,且气含率梯度变化更均匀;增加破泡装置后,在相同气速条件下气泡上升速度下降,气体在液层中的滞留时间延长,使鼓泡层高度增加,可显著提高传质效率,且降低了气体雾沫夹带量;破泡装置还明显改善了气相的纵向分布,气含率由塔板底部向上逐渐增大且存在明显分界;破泡装置附近湍动较剧烈,气泡破碎喷出的气体会进一步撕裂液膜,气体破碎作用会抑制气泡聚并,促进界面的快速更新更有利于传质过程的进行。研究结果可对工业塔板设计和优化提供指导。     

分析关口表电能采集系统现场故障排查技术

本文对关口表电能采集系统现场故障排查技术进行了简单分析.并提出了相关解决措施.