煤焦油碳基固体酸催化合成2-叔丁基-5-甲基苯酚

合成了煤焦油碳基固体酸,并对其结构进行了表征.通过叔丁醇与问甲基苯酚合成了2-叔丁基-5-甲基苯酚,探讨了煤焦油碳基固体酸对烷基化反应的催化活性.实验结果表明,煤焦油碳基固体酸是烷基化反应的良好催化剂,在间甲基苯酚0.01 mol、催化剂用量为0.1 g、反应温度为110℃、反应时间为3 h、醇酚摩尔比为2.5:1的优...     

从核结构的有序性理解180，182Hf核形状演化

对于发生在同1个原子核中的从一种高激发模式向着低激发模式演化的物理图像,给出了一种新的理解：被布居到高角动量态的高有序激发核,以E2跃迁的方式先行退耦到转晕带,再退耦到共存区(或临界点)时释放了有序的结构能,诱发价核子对耦合强度改变,重新组合出低有序的激发模式基准态,实现了基准态结构的过渡;从微观上看,这是一种既温和而又平稳的转变。这种共存区(或临界点)在不同核素中位置的改变,就是研究基态量子相变的理论基础。文章阐述了连续发生两次这类相变的可能,并以180,182Hf核为例作了深入探讨。     

NdFeB磁性材料化学镀Ni-Cu-P合金沉积机理研究

通过对不同时间序列(0.5、1、10、20、40、60min)镀层的深入研究,提出Ni-Cu-P非晶态合金镀层形核与长大过程的沉积模型,并对不同时间序列非晶态合金镀层的形貌和结构研究表明:在施镀初期,Ni、Cu原子团优先沉积于基体表面能量较高的部位,并开始形核且以不规则形态长大;在施镀后期,随着P含量的不断增加,镀层形貌逐渐由不规则形态变为规则胞状形态,直至形成光滑平整的非晶态镀层。     

基于Quaternion-Gabor滤波器的彩色纹理分割算法研究

提出一种的简单快速的多通道Gabor滤波技术对彩色纹理进行分割。首先,通过DRBFT和IDRBFT对彩色纹理的进行多通道Gabor滤波,再运用PCA对滤波得到的特征向量进行降维,对降维后的特征向量进行k-mean聚类,最后再对聚类后的区域用mean shift进行平滑,通过对平滑后的区域进行边缘检测就可以得到不同纹理的边界。最后给出几种分割算法的实验结果比较,表明该算法对于分割彩色纹理还是非常有效的。     

变工况滚动轴承故障诊断方法综述

智能制造背景下,旋转机械工况更加复杂,运行条件更加严峻,设备的运行状态监测与故障诊断更加重要。变工况条件下,轴承振动信号存在幅值变、脉动冲击间隔、采样相位不恒定和信号噪声污染等特点,传统滚动轴承故障诊断方法的应用受到了限制。针对变工况条件下的轴承故障诊断技术,发展了以阶次跟踪、时频分析、随机振动以及混沌理论等人工提取特征的信号解调与分析方法、以卷积神经网络、自编码器与深度置信网络为代表的深度学习方法以及迁移学习方法。回顾近五年变工况轴承故障诊断领域的进展,从算法原理、算法优化以及算法实际应用等角度,详细介绍几种当前主流的变工况故障诊断方法,讨论各类算法的优势不足及适用场景,为后续的研究指明方向。     

A study of the reaction kinetics of SOCl2 in electrolytes containing AlCl3 or LiAlCl4

The reaction mechanism of SOCl₂ in electrolytes containing AlCl₃ or LiAlCl₄, and the factors affecting the capacity of carbon electrodes inThe capacity of the carbon electrode is found to be dependent on its porosity, i.e., the greater the porosity, the higher the capacity. The electroA study of the reduction mechanism of AlCl₃/SOCl₂ and LiAlCl₄/SOCl₂ electrolytes on platinum has been conducted using cyclic voltammetr     

Improved fish migration optimization method to identify PEMFC parameters

In a worldwide environment context where the emergency need to decrease pollutant emissions is an important issue, the research for solutions is increasing. Fuel cell technology is anticipated to become a practicable approach for solving the problem of pollution due to its environmentally friendly characteristics. In this work, a novel problem formulation is suggested for the efficient recognition of PEMFC parameters which the solving is by using the Improved Fish Migration Optimizer (IFMO) technique. After coding the steps of the algorithm in MATLAB, the objective function is resolved for the fuel cell. Comprehensive simulations evaluate the formulation performance with the suggested and traditional objective functions; then, the outcomes are compared. To confirm the suggested formulation ascendancy compared to the traditional curve-fitting method, a complete assessment based on convergence rate, the value of the objective function, and the value of absolute voltage error are performed. The achieved value of the objective function, absolute voltage error, and average time of computation is 0.005, 0.4, and 1.63, respectively. Environmentally, the combustion of hydrogen and its use in PEMFC produce no carbon dioxide.     

Non-noble metal ultrathin MoS2 nanosheets modified Mn0.2Cd0.8S heterostructures for efficient photocatalytic H2 evolution with visible light irradiation

A series of non-noble metal ultrathin MoS₂ nanosheets modified Mn_0.2Cd_0.8S heterostructured composites were prepared by an ultrasonic assisted hydrothermal synthesis process. Comparing with the pristine Mn_0.2Cd_0.8S composite, the obtained ultrathin MoS₂/Mn_0.2Cd_0.8S composites exhibited a significantly improved photocatalytic activity for hydrogen evolution from water with visible light response. The optimized photocatalytic activity toward MoS₂/Mn_0.2Cd_0.8S composite is around 8 times of the pristine Mn_0.2Cd_0.8S composite. Moreover, the ultrathin MoS₂/Mn_0.2Cd_0.8S composites displayed good photocatalytic stability in the course of photochemical reaction. The excellent photocatalytic activity of the ultrathin MoS₂/Mn_0.2Cd_0.8S composites might be attributed to the formed heterojunctions in composites itself and the sufficient active edge sites in MoS₂ phase. A possible photocatalytic mechanism was tentatively proposed. Considering its excellent photocatalytic activity and good photochemical stability, the obtained ultrathin MoS₂/Mn_0.2Cd_0.8S composite has potential application in photocatalytic hydrogen evolution from water by using solar energy.     

Special Z-scheme CdS@WO3 hetero-junction modified with CoP for efficient hydrogen evolution

In order to explore new materials capable of producing the new energy hydrogen, co-catalyst CoP was successfully modified Z-scheme hetero-junction CdS@WO₃ to achieve efficient splitting of water under visible light. With the lactic acid solution as sacrificial agent, the H₂ production was 736.89 μmol corresponding the apparent quantum yield of 1.72%, which was 20.2 and 24.5 times than pure CdS and WO₃, respectively. The results of XRD, TEM and FESEM characterization showed that the catalyst has obvious micro-morphology and high crystallinity. The valence distribution and composition of elements in the catalyst were measured by XPS. UV-vis, PL and electrochemical detection showed that the catalyst has excellent optical and electrical properties such as rapidly photo-generated charge transfer efficiency. Not only the energy band structure of the catalyst was calculated and analyzed, simultaneously the charge transfer mechanism and HER mechanism were explored and proposed.