LaCr0.7Fe0.3O3-NiMn2O4 supported NTC composite ceramics with a sandwich-like structure

A novel sandwich-like structure was first proposed to adjust the electrical properties of NTC thermistors. The LaCr_0.7Fe_0.3O₃-NiMn₂O₄ supported composite ceramics with sandwich-like structure were initially fabricated via traditional solid-state reaction and uniaxial pressing methods, which allowed for the advantages of each component to be integrated into one material. X-Ray diffraction analysis indicates the ceramics mainly consisting of orthorhombic perovskite LaCr_0.7Fe_0.3O₃ and cubic spinel NiMn₂O₄ phases. SEM images manifest that the three layers adhered well to each other and exhibited high density. For electrical properties, the ρ_25°C was expanded to a wide range of 1182–110,233 Ω?cm and could be adjusted to the desired values by tuning the volume ratio of two basic layers, the B value was enhanced from 3358 K to 4167 K by NiMn₂O₄, and the thermal stability was improved by LaCr_0.7Fe_0.3O₃ with a resistance shift less than 0.55 % after annealing at 150 °C for 1500 h.     

一种5-甲磺酰基-1H-吡啶-2-酮的合成方法

以5-溴-2-甲氧基吡啶为原料,经取代、过氧化、脱甲基化3步制备了5-甲磺酰基-1H-吡啶-2-酮.取代过程选用正丁基锂先与5-溴-2-甲氧基吡啶进行卤素-锂交换反应,再用二甲基二硫醚进行亲核取代,反应彻底且收率较高.过氧化过程选用间氯过氧苯甲酸作为过氧化剂,将甲硫基氧化为甲磺酰基,此步选用n(2-甲氧基-5-甲硫基吡啶)∶n(间氯过氧苯甲酸)=1.00∶2.50的投料比,有较好的收率.在脱甲基化过程中选用氢溴酸醋酸溶液进行脱甲基化,目标产物直接在醋酸中析出,提纯较为简便.目标产物的总收率为58.03％,其结构经1H NMR、13C NMR和IR确证.该方法操作简单,收率较高,易提纯,可大批量生产.     

Numerical modeling of effect of slot on bubble motion in aluminum electrolytic process

A transient three-dimensional (3D) model was established to understand the bubble motion in an industrial electrolytic process. An anode with a new design was tested. It incorporates two slots that allow an efficient removal of gas bubbles. The electromagnetic fields were described by solving Maxwell's equations. The bubble movement was studied with two-way coupling Euler–Lagrange approach. The interplay of current density and bubble nucleation rate was included. The collision and coalescence of bubbles were considered. Random walk module was invoked for involving the chaotic effect of the turbulence. The numerical results were validated by experimental measurements. The results indicate that the current distribution and the bubble nucleation periodically change. Due to the slot, the bubble elimination heavily increases. The contribution of the slot to the bubble removal exceeds 50% in the case of three currents, and the promotion of the slot decays with increasing the current.     

Investigation on the anti-reduction mechanism of Ti4+ in high dielectric constant system Ca0.9La0.067TiO3 by doping with Al2O3

Ca_0.9La_0.067TiO₃ (abbreviated as CLT) ceramics doped with different amount of Al₂O₃ were prepared via the solid state reaction method. The anti-reduction mechanism of Ti⁴⁺ in CLT ceramics was carefully investigated. X-ray diffraction (XRD) was used to analyze the phase composition and lattice structure. Meanwhile, the Rietveld method was taken to calculate the lattice parameters. X-ray photoelectron spectroscopy (XPS) was employed to study the valence variation of Ti ions in CLT ceramics without and with Al₂O₃. The results showed that Al³⁺ substituted for Ti⁴⁺ to form solid solution and the solid solubility limit of Al³⁺ is near 1.11 mol%. Furthermore, the reduction of Ti⁴⁺ in CLT ceramics was restrained by acceptor doping process and the Q × f values of CLT ceramics were improved significantly. The CLT ceramic doped with 1.11 mol% Al₂O₃ exhibited good microwave dielectric properties: ε_r = 141, Q × f = 6848 GHz, τ_f = 576 ppm/°C.     

可重构制齿生产线能效监控系统设计与实现技术研究

针对制齿生产线耗能设备众多、能耗环节及能量源组件多、能量流动复杂等特点,从面向低碳制造的能效集成监控与系统可重构的角度,在分析制齿生产线能量源构成和主要能效指标的基础上,提出了一种包含物理资源层、智能感知层、核心功能层、系统交互层和基础支撑层的可重构制齿生产线能效监控系统的设计和实现方案,对支持该系统实现的基于软插件的异构数控机床能效数据采集技术进行了研究,通过进一步的数据分析处理实现了制齿生产线的能效实时监控与管理,并提出了一种制齿生产线能效监控的动态可配置方法,以适应制齿生产线的物理配置变动和能效监控需求变化的可重构性。最后,基于上述系统架构及关键实现技术,结合某集团轿车齿轮制齿生产线实际情况进行了系统的开发和初步应用。     

加压酸浸法从烟化炉冰铜中浸出铜和镍的试验研究

烟化炉冰铜主要是采用烟化炉处理低品位铜、锡、镍、锌等物料时产生的中间产物，主要含铜、镍、铁、硫等元素，从中浸出铜和镍具有重要价值。采用加压酸浸法从烟化炉冰铜中浸出铜和镍，试验研究了时间、温度、氧分压、液固比、粒度等因素对铜、镍、铁浸出率的影响。试验结果表明：烟化炉冰铜粒度球磨至小于75μm、温度433K、时间3h、氧分压为0.6MPa、液固比4/1mL/g、木质素磺酸钠用量为2‰的优化条件下，铜、镍、铁浸出率分别平均为98.18%、98.42%和26.46%。     

Smartphone-based bulky waste classification using convolutional neural networks

Multimedia Tools and Applications - The rapid urbanization process is escalating the urban waste problem, and ineffective management has worsened the issue, leading to severe consequences to the...     

Determination of Metastable Zone Width and Nucleation Induction Period of Palm Oil and its Olein/Stearin in Melting Layer Crystallization

Measurement methods of metastable zone width (MZW) and nucleation induction time for melting layer crystallization of palm oil (PO) and its olein/stearin (POL/PST) were established, and the effects of cooling rate (corresponding to various supercoolings) on MZWs and induction time for melting layer crystallization of PO, POL, and PST were determined. The results indicated that the MZW coherently rose with increasing cooling rates with respect to PO and POL, while it declined with higher cooling rates for PST. The induction period results demonstrated that the nucleation induction periods of PO, PST, and POL decreased with increasing supercoolings, and the lag time for nucleation negatively correlated to the melting point of oils at the same supercooling. These data could offer significant instruction in designing and controlling the melting layer crystallization process for palm oil.     

轨腰仿生自分层防腐梯度涂料合成及影响因素和结构探究

目的仿荷藕结构及功能,制备一种自分层防腐涂料。方法合成聚氨酯改性环氧树脂(PU/EP)及氟硅改性丙烯酸树脂(氟硅改性PAA),将两种树脂共混形成自分层涂料。通过铅笔硬度测试、机械性能测试、接触角测试、耐老化测试、划格法附着力测试、电化学阻抗测试等,分别评价两种树脂比例、混合溶剂比例对涂膜自分层行为及性能的影响,并通过SEM-EDS、红外光谱等表征技术分析涂膜分层后的结构。结果当PU/EP∶氟硅改性PAA=1∶1时,接触角达到96.0°,柔韧性为0.5 mm,耐冲击为50 cm,附着力等级为1,失光率降至19%;乙酸丁酯(NBAC)∶正丁醇(NBA)=4∶6时,涂膜分层情况良好,接触角达到107.7°,浸泡水中48 h耐水性无变化,失光率降至17%。SEM-EDS、红外光谱分析表明,自分层涂膜上层为氟硅改性PAA、底层为PU/EP,中间存在过渡涂层,过渡层两种树脂中的─COOH、─OH、环氧基发生反应,使整个涂层更具稳定性。经由EIS分析,在3.5%NaCl溶液中浸泡40天后,腐蚀介质没有渗透涂膜到达基底金属界面。结论制备的轨腰仿生自分层涂膜的机械性能、附着力、疏水性、耐老化、防腐蚀性能优异,涂膜结构稳定。