Hydroxyl Groups Promoted Ag Dispersion and Excellent Performance of Ag/Al2O3 Catalyst for HCHO Oxidation

Catalysis Letters - Hydroxyl groups are considered as anchoring sites for active components on catalysts. Guided by this viewpoint, 4 wt. % Ag/Al2O3 catalyst derived from Boehmite (AlOOH) was...     

基于价电子理论的Ag-Sn金属间化合物形成机理

SnAgCu焊点中的金属间化合物(intermetallic compounds,IMCs)Ag3 Sn脆性大且电阻高,对焊点可靠性具有重要影响,有必要明确其形成过程和相变机制以控制其生长.采用固体与分子经验电子理论(empirical electron theory,EET)研究Ag-Sn系统中的主要扩散元素及原子运动路径,应用自洽键距差(self-consistent bond length difference,SCBLD)法计算了Ag-Sn系统内参与反应相的价电子结构及可能形成的固溶体的结合能,根据结合能变化趋势从价电子层面描述出Ag3 Sn在焊点内部的形成过程.研究结果表明:Ag-Sn系统中的主要扩散元素为Sn,Sn原子进入Ag晶胞形成固溶体,固溶体内原子重新排布,形成结合能更高、排布更均匀的共价键,造成晶格膨胀,位于(110)晶面和面心位置的Ag原子随之向外扩张,形成了同样具有良好对称性的Ag3 Sn,与前人研究Ag-Sn系统扩散的实验结果相符.     

基于胸围-腹围的湖南地区孕妇装号型制定的研究

针对采集的湖南地区孕妇体型数据,基于胸腹差和臀腹差,运用聚类分析,将孕妇体型分为H型、O型、A型和V型4类.确定孕妇装号型的基本部位,提出孕妇服装号型制定的方法,即上装以人体身高厘米数为号、人体胸围厘米数为型,下装以人体身高厘米数为号、人体腹围厘米数为型,利用线性回归分析给出了号型推档数值,并形成4种体型孕妇装号型系列表.论文成果能为孕妇装号型推荐和孕妇装设计提供理论基础,以此可有效提高孕妇服装的合体性.     

短视频对服装服饰类用户购买意愿的影响

短视频营销已成为当前助推消费升级的重要新生力量,研究其对用户购买意愿的影响对提升产品销量具有重要的理论意义和实践价值.通过文献总结分析,借助SOR理论模型,提出研究假设,构建探究服装服饰类短视频对用户的购买意愿影响模型,并通过结构方程模型进行验证分析.结果表明:短视频的有用性、易用性显著正向影响用户的购买意愿,而娱乐性影响不显著;感知匹配度在有用性、易用性、娱乐性刺激变量和购买意愿反应变量间存在中介作用.针对上述结论,建议服装服饰类短视频运营企业商家注重在有用性、易用性、感知匹配度方面进行改进,促使短视频营销更快更好的发展.     

Design of the broadband microstrip array antenna for blast furnace surface monitoring

Aiming at the requirements of high-resolution imaging and high integration of the blast furnace radar,this paper presents a method for designing a wideband microstrip array antenna,which broadens the antenna bandwidth through the design of parasitic patches and air layers.By combining multi-input multi-output (MIMO) radar and synthetic aperture radar (SAR) imaging principles,a linear MIMO array is designed,and a near-field simulation imaging experiment is performed on the simulated feed line through the wave number domain imaging algorithm.Simulation results show that the gain of the main lobe of the antenna can reach 14.05 dBi,the reflection coefficient is less than -10 dB,the absolute bandwidth is 5.25 GHz,the operating frequency is 20.67~25.92 GHz,and the range resolution is increased to 3 cm compared with the existing blast furnace radar.The average error of the azimuth direction of the simulated material line imaging is 0.008 m,and the range direction is 0.0011 m.Compared with the traditional microstrip array antenna,this antenna effectively widens the bandwidth,and the range resolution is higher than that of the traditional blast furnace radar.It can accurately obtain the shape information on the simulated material line,and has an engineering application value for blast furnace surface monitoring.     

Adaptive simulated annealing particle swarm optimization algorithm

Particle swarm optimization is widely used in various fields because of the few parameters to be set and the simple calculation structure.In order to improve the optimization speed and accuracy of the PSO,and to avoid falling into the local optimal solution,an adaptive simulated annealing PSO is proposed,which uses the hyperbolic tangent function to control the inertia weight factor for nonlinear adaptive changes,uses linear change strategies to control 2 learning factors,introduces the simulation annealing operation,set a temperature according to the initial state of the population,guide the population to accept the difference solution with a certain probability according to the Metropolis criterion,and ensure the ability to jump out of the local optimal solution.To verify the effect of the algorithm proposed in this paper,7 typical test functions and 5 algorithms proposed in the literature are selected for comparison and testing.According to the average value,standard deviation and number of iterations of the optimization results,the algorithm proposed in this paper has greatly improved the iteration accuracy,convergence speed and stability so as to overcome the shortcomings of particle swarm optimization.     

西方的东方学及其功能属性

西方的"东方学"作为与古典学、人类学相并列的三大学术领域之一,具有悠久的历史传统,它既是作为一门学问的"东方学",也是作为一种思想形态的"东方观".西方人的自我确认、与他者文化的区分与辨异,都离不开"东方"的存在,而且都围绕"东方专制主义""亚细亚生产方式""东方停滞论""东方神秘主义"四个关键词展开.不同历史阶段西方人"东方"视野的移动伸缩、对"东方—西方"的认同与辨异、结构与解构模式的交互运动,都出于自身文化的内在需要,由此形成了关于"东方"的知识体系与思想传统.研读西方"东方学"著作,揭示其"西方文化认同"与"东西文化辨异"的功能,分析其知识形态与意识形态的双重属性,可以为中国的"东方学"学术史的研究提供外部参照与国际背景.     

"聚合性":巴赫金与陀思妥耶夫斯基

以往对巴赫金"复调"及"外位性"概念的理解多关注其对话的开放性,而往往忽略其基于"涵义"概念的统一性.巴赫金的统一性观念在文化的叙事结构中是对"聚合性"的移置,在诗学层面上是对陀思妥耶夫斯基"博爱的统一"叙事的抽绎.因此,要理解陀思妥耶夫斯基的复调,既需要借助于外位性概念,也要理解这些概念背后的文化叙事结构.     

一类负模量Kirchhoff - Carrier方程的解

利用变分方法和反证法研究了一类含有非线性项的Kirchhoff - Carrier方程,证明了当0<λ1时,该方程至少存在一对非平凡解,且当λ≥a λ₁时该方程不存在同号解.     

中国耕地细碎化的理论解析与研究框架

基于演绎推理法和文献研究法,探索耕地细碎化的概念、过程、机制和效应,并构建耕地细碎化研究框架,为耕地细碎化研究提供理论指导。结果表明:①耕地细碎化是耕地在自然-人为双重因素驱动下,耕地地块在形态上不断分割、变小,耕地产权在主体上不断细分、多元的过程,并分别表现为相互关联又有所区别的耕地景观细碎化和耕地权属细碎化; ②耕地细碎化研究应遵循“诊断-机制-效应-治理”的理论框架,耕地细碎化诊断需从形态和权属两方面构建评价指标体系,形成机制可从自然切割力、利用切割力、设施切割力和管理切割力4个方面揭示不同因素的作用机制,效应需揭示不同尺度下耕地细碎化形态和产权的趋势性转折对经济、社会和生态的影响,治理研究应按照“问题识别治理潜力治理路径保障措施”的逻辑顺序构建。