云边协同助力行业数字化转型

随着边缘计算的快速发展,边缘计算在各行业中的应用也越来越广泛.分析了云边协同在典型场景下的应用需求和业务模式,对云边协同在不同行业场景下的重要作用进行了介绍,最后给出了云边协同未来的发展趋势.     

铁氧化物在流化床温度和CO气氛下的形态迁移及其对NO催化还原

利用小型固定床实验台实验研究了铁氧化物在典型流化床温度和CO还原性气氛下的形态迁移及其生成物对NO的催化还原作用，采用分级还原结合X射线衍射（XRD）表征分析，确定铁氧化物与CO和NO反应后生成物的价态及各种铁氧化物对NO的还原机制。结果表明，Fe₂O₃在实验条件下可依次被CO还原为Fe₃O₄、FeO和单质铁，反应过程中随着还原度的增加，还原速率逐级下降，从Fe₂O₃还原到Fe₃O₄的速率最高，FeO还原到Fe速率最低，在实验温度范围内，床温升高有利于提高Fe₂O₃到Fe₃O₄的还原速率和还原度。不同形态的铁氧化物对NO的催化还原特性不同，Fe₂O₃及其部分还原后生成的Fe₃O₄都不能直接与NO反应，Fe₂O₃对CO催化还原NO的效果很弱，而Fe₃O₄对CO还原NO的反应却有很强的催化作用，而进一步还原生成FeO与单质铁还可直接与NO反应。     

矿井地面风硐的改造方案比选与施工

为解决通风系统改造后原地面风硐断面偏小、风速超限的问题,通过在原有地面风硐东侧并联一道钢制矩形通风管道的方法,从而增加风硐断面积,降低风硐内的风速和通风阻力,效果明显。     

Proposed network structures and combined adaptive algorithms for electrocardiogram signal denoising

An electrocardiogram (ECG) signal is a record of the electrical activities of heart muscle and is used clinically to diagnose heart diseases. An ECG signal should be presented as clear as possible to support accurate decisions made by doctors. This article proposes different combinations of combined adaptive algorithms to derive different noise-cancelling structures to remove (denoise) different kinds of noise from ECG signals. The algorithms are applied to the following types of noise: power line interference, baseline wander, electrode motion artifact, and muscle artifacts. Moreover, the results of the suggested models and algorithms are compared with those of conventional denoising tools such as the discrete wavelet transform, an adaptive filter, and a multilayer neural network (NN) to ensure the superiority of the proposed combined structures and algorithms. Furthermore, the hybrid concept is based on dual, triple, and quadruple combinations of well-known algorithms that derive adaptive filters, such as the least mean squares, normalized least mean squares and recursive least squares algorithms. The combinations are formulated based on partial update, variable step-size (VSS), and second iterative VSS algorithms, which are considered in different combinations. In addition, biased NN and unbiased linear neural network (ULNN) structures are considered. The performance of the different structures and related algorithms are evaluated by measuring the post-signal-to-noise ratio, mean square error, and percentage root mean square difference.     

地勘单位转制后税务风险识别与控制

结合“减税降费”的政策背景,以陕西省某转制地勘单位为例,引入风险控制相关理论并应用层次分析法,构建了税务风险评估指标体系,对转制地勘单位面临的税务风险进行了识别、分析、评估。研究结果表明:针对不同的税收类型,应着重关注不同方面的风险,排序前6位的风险依次为企业所得税扣除类风险、增值税决策环节风险、增值税销售环节风险、房产税计税依据风险、企业所得税税收优惠类风险、增值税采购环节风险;并对上述风险的控制机制进行了分析,从企业管控、政策优化两方面分别提出了相关对策和建议。     

How to choose endothermic process for thermochemical waste-heat recuperation?

The thermochemical waste-heat recuperation (TCR) systems by steam reforming of various hydrocarbon fuels are considered. A method for determining the TCR systems efficiency is proposed. The methodology is based on the determination of the heat recuperation rate and heat transformation coefficient. TCR due to steam reforming of methanol, ethanol, glycerol, propane, and methane was analyzed. To obtain the initial data for energy analysis of TCR systems, the thermodynamic analysis was performed. With the help of Aspen HYSYS was determined the synthesis gas composition and reaction enthalpy for all investigated variants. The investigation was performed for a wide temperature range from 400 to 1200 K, for the steam-to-fuel ratio of 1, and pressures of 1 bar. It was established that TCR due to the steam reforming of ethanol, glycerol, and propane in the temperature range above 800 K, it is possible to achieve complete recuperation of the exhaust after the furnace. As a results of investigation, the practical recommendations were given for choosing endothermic reaction for the thermochemical waste-heat recuperation systems: in the temperature range up to 600 K for TCR it is necessary to choose a methanol steam reforming reaction; in the temperature range from 600 to 1000 K - the reaction of steam reforming of ethanol and glycerol; in the temperature range above 1000 K - the reaction of steam reforming propane and methane.     

High pressure modifications in amorphous boron suboxide: An ab initio study

Using constant pressure ab initio calculations, we probe the high-pressure modifications in amorphous boron suboxide (B₆O) consisting of glassy boron trioxide (B₂O₃) and boron (B) domains up to a theoretical pressure of 100 GPa. At this pressure, the structure remains amorphous. We find a steady increase in the average coordination of both B and oxygen (O) atoms. O atoms mostly attain threefold coordination as in B₂O₃ glass at high pressures. On the other hand, the mean coordination number of B-atoms reaches six at high pressures and the structural changes in B-rich regions are perceived to be quite analogous to those of amorphous B. B₁₂ clusters are found to persevere during the pressurizing process and the high-pressure modifications occur predominantly around O-atoms and the regions that connect the pentagonal pyramid-like motifs to each other. Upon pressure release, some high-pressure configurations persist in the model and another noncrystalline structure being about 10% denser than the original state is recovered, suggesting a permanent densification and a possible irreversible amorphous-to-amorphous phase transformation in B₆O. The recovered network shows slightly better mechanical properties than the uncompressed model. During the compression and decompression processes, amorphous B₆O remains semiconducting. The delocalization of some band tail states is seen at high pressures.     

Thermal and transport properties of as-grown Ni-rich TiNi shape memory alloys

Electrical resistivity, Seebeck coefficient, specific heat and thermal conductivity measurements on the Ti_50−xNi_50+x (x = 0.0–1.6 at.%) shape memory alloys are performed to investigate their thermal and transport properties. In this study, anomalous features are observed in both cooling and heating cycles in all measured physical properties of the slightly Ni-rich TiNi alloys (x ≤ 1.0), corresponds to the transformation between the B19′ martensite and B2 austenite phases. Besides, the transition temperature is found to decrease gradually with increasing Ni content, and the driving force for the transition is also found to diminish slowly with the addition of excess Ni, as revealed by specific heat measurements. While the signature of martensitic transformation vanishes for the Ni-rich TiNi alloys with x ≥ 1.3, the characteristics of strain glass transition start to appear. The Seebeck coefficients of these TiNi alloys were found to be positive, suggesting the hole-type carriers dominate the thermoelectric transport. From the high-temperature Seebeck coefficients, the estimated value of Fermi energy ranges from ∼1.5 eV (Ti_48.4Ni_51.6) to ∼2.1 eV (Ti₅₀Ni₅₀), indicating the metallic nature of these alloys. In addition, the thermal conductivity of the slightly Ni-rich TiNi alloys with x ≤ 1.0 shows a distinct anomalous feature at the B19′ → B2 transition, likely due to the variation in lattice thermal conductivity.     

Producing fully-lamellar microstructure for wrought beta-gamma TiAl alloys without single α-phase field

Fine-grained fully-lamellar (FL) microstructure is desired for TiAl components to serve as compressor/turbine blades and turbocharger turbine wheels. This study deals with the process and phase transformation to produce FL microstructure for Mo stabilized beta-gamma TiAl alloys without single α-phase field. Unlike the α + γ two-phased TiAl or beta-gamma TiAl with single α-phase field, the wrought multi-phase TiAl–4/6Nb–2Mo–B/Y alloys exhibit special annealing process to obtain FL microstructure. Short-term annealing at temperatures slightly above β-transus is recommended to produce the desired FL microstructure. The related mechanism is to guarantee the sufficient diffusion homogenization of β stabilizers during single β-phase annealing, and further avoid α decomposition by α → γ + β when cooling through α + β + γ phase field. The colony boundary β phase contributes to fine-grained nearly FL microstructure, by retarding the coarsening of the α phase grains.     

Strong coupling effects during Cu/In/Ni interfacial reactions at 280 °C

The substantial heat generated in three-dimensional integrated circuits and high-power electronics has made thermal management a critical challenge for reliability in the electronics industry. Pure indium solder has been used as a thermal interface material to minimize the contact thermal resistance between a chip and its heat sink. Indium and indium-based alloys are potential lead-free solder for low-temperature applications. Heat sinks in the heat dissipation system as well as substrates of electronic joints are usually made of copper, with nickel being the most commonly used diffusion barrier on the chip side. Therefore, the Cu/In/Ni sandwich structure would be encountered in electronic devices. The soldering process for forming the Cu/In/Ni structure crucially determines the reliability of devices. In this study, Cu/In/Ni interfacial reactions at 280 °C were investigated. Intermetallic compounds were identified and the microstructural evolution was observed. A strong coupling effect between Cu and Ni was found, which caused several peculiar phenomena: (1) the formation of a Cu–In compound (the Cu₁₁In₉ phase) at the In/Ni interface; (2) the formation of two sub-layers of the Cu₁₁In₉ phase at the Cu/In interface; (3) the formation of faceted rod-like Cu₁₁In₉ grains; and (4) the formation of a half-Cu₁₁In₉, half-Ni₃In₇ microstructure after prolonged reactions. The mechanism of phase transformations is elucidated based on the calculated Cu–In–Ni ternary phase diagram using CALPHAD thermodynamic modeling.