Complete convergence of weighted sums for arrays of rowwise φ-mixing random variables

In this paper, we establish the complete convergence and complete moment convergence of weighted sums for arrays of rowwise φ-mixing random variables, and the Baum-Katz-type result for arrays of rowwise φ-mixing random variables. As an application, the Marcinkiewicz-Zygmund type strong law of large numbers for sequences of φ-mixing random variables is obtained. We extend and complement the corresponding results of X. J. Wang, S. H. Hu (2012).     

用振幅矢量法计算光栅衍射的光强分布

本文介绍一种在普通物理阶段严格计算光栅衍射光强分布的振幅矢量方法，此方法回避了困难的菲涅耳－基尔霍夫积分，这通常在普通物理中是不被采纳的．用振幅矢量法计算有两个显著的优点，一个是物理概念清楚，另一个是计算简单严格     

Propagation of optical beams in strongly nonlocal nonlinear media

The propagation of arbitrary laser beams in strongly nonlocal nonlinear media is investigated based on the ABCD matrix. The second-order moment beam width and the mean curvature radius are derived under the off-waist incident condition.     

信息高速公路与校园网

从信息高速公路内涵出发，联系到校园网的建设，提出学校计算机教育的目标及一种实现与ＩＮＴＥＲＮＥＴ相联的方式。     

Hydrothermal Synthesized Co-Ni3S2 Ultrathin Nanosheets for Efficient and Enhanced Overall Water Splitting

We used the one-step hydrothennal controlled synthesis method for Co-Ni3S2 ultrathin nanosheets grown directly on nickel foam(NF).The as-synthesized Co-Ni3S2/NF showed eiilianced activities in the hydrogen evolution reaction(HER),oxygen evolution reaction(OER)and better overall water splitting(OWS)efficiency than the iin-doped Ni3S2/NF.the voltage of Co-Ni3S2/NF for OWS was only 1.58 V at the current density of 10 niA/cm^2 and with long time(>30 h)current output during the current-density(i-t)test.The good i-t pertonnance was also observed in both HER and OER processes.Additionally,the Co-Ni3S2/NF showed a large current density(>1A/cm^2)for both HER and OER.Wlien the current densities reached 100 and 1000 mA/cm^2,the required overpotentials tor Co-Ni3S2/NF were 0.35 and 0.75 V for OER and 0.30 and 0.85 V for HER.Therefore,after introducing Co,the activity of Ni3S2-based material was strongly enhanced.     

Micro-gated-field emission arrays with single carbon nanotubes grown on Mo tips

Using our approach previously reported, we have fabricated relatively large area micro-gated-field emission arrays with carbon nanotube (CNT) grown on Mo tips. By redesigning the device and fabrication processes, the percentage of single CNTs increased to about 50-70% with a substantial improvement in leakage current between gate and cathode and gate interceptive current. The I-V measurement of a 11000 cell array at a gate to cathode voltage of 92 V showed an anode current of 1.2 mA, corresponding to a current density of 0.57 A/cm², with a gate current only 3.3% of the anode current.     

Fundamental frequency patterns of Chinesein different speech modes

I.IntroductionTheF,patternsofspeechareimportantnotonlyforthcprosodicfeaturesbuta1soforvoicesourcecharactcristics.Nowmoreandmorespeechscientistsrecognizedthatvoiceexcitationsourceintcxt-to-spccchsystemsp1aysanimportantro1elnbothintclligibilityandnaturalnessorsynthcticspcech.Espccially,forChinese,atone1anguagewithmulti-tonesystem,thetonalpatternswhicharcmainlydcmonstratedintheF,con-tourscarry1exicalmeaning.SomecomparativestudiesoftheF,pattcrnsinbetweentonelanguage(Chinese)andstress1anguage(En…     

简单共聚模型的分布函数与组成方程推导

针对自由基共聚合反应歧化终止和偶合终止两类机理生成的线型共聚物,应用统计物理的基本原理,对处于最可几分布状态下的线型共聚物分子量分布函数进行了理论推导,并以此分布函数,结合自由基共聚合机理动力学处理和概率计算,从另一种途径得到Mayo-Lowis和Alfrey-Goldfinger简单共聚物组成方程,研究结果有助于进一步理解简单共聚模型组成方程的物理学基础,同时也将为线型自由基共聚合反应机理的研究提供一个新方法.     

Self-assembly of silica nanosheets on titanium fibers for solids-phase microex⁃traction of UV absorbers in environmental water samplesEI北大核心CSCD

Silica nanosheets （SiO2NSs）were successfully assembled on titanium （Ti）wires by sol-gel method. TiO2 nanosheets （TiO2NSs）were grown in situ on Ti wires using anodic oxidation in a fluoride-containing electrolyte to obtain Ti@TiO2NSs. The Ti@TiO2NSs@SiO2NSs fibers were obtained by coating Ti@TiO2NSs with SiO2NSs. It was characterized by scanning electron microscopy （SEM） and X-ray energy dispersive spectroscopy （EDS）. The fibers were used for solid-phase microextraction of ultraviolet absorbers （UVFs）. Under the optimized conditions, six UVFs presented good linearity with the correlation coefficients （R2） greater than 0.999, and the limits of detection （LODs）ranged from 9 to 59 ng/L. The intra-day and inter-day relative standard deviations （RSDs） were from 4.3% to 5.1% and 4.6% to 5.8% for a single fiber at the spiked level of 25 μg/L, respectively. The developed method was successfully applied to the selective enrichment and determination of target UVFs in environmental water samples with recoveries from 93.2% to 108.1% and RSDs from 4.5% to 7.1%. Moreover, the fiber can be fabricated in a precisely controllable manner and is stable for at least 200 extraction and desorption cycles. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

介电弹性作动器主动隔振模糊控制试验研究

采用模糊控制策略,开展介电弹性作动器的主动隔振性能试验研究。基于介电弹性材料的Maxwell应力模型建立了作动器的力电耦合模型,分析了作动器的非线性特性;针对隔振系统设计了Mamdani型模糊控制器,建立了控制电压信号与振动响应之间的关系;在此基础上,开展了介电弹性作动器主动隔振试验研究,并与加速度反馈控制进行了对比。试验结果表明,在相同驱动电压的情况下,基于模糊控制策略的主动隔振性能要优于加速度反馈控制,且能够显著降低由于非线性驱动力导致的倍频响应幅值,有助于提高隔振系统的稳定性。