Li2O-2B2O3熔体的物性研究

系统测量了四硼酸锂(Li2O-2B2O3)熔体的密度ρ、表面张力γ随着温度的变化规律,实验结果表明在1100K到1500K范围内Li2O-2B2O3高温熔体的密度和表面张力随着温度的升高均线性减小.通过实验数据拟合得出熔体密度与温度关系为ρ(T)=2.574-4.89×10-4T,熔点处LiO-2B2O3熔体的密度为1.992g/cm3;熔体表面张力与温度关系的拟合公式为γ=262.8-4.59×10-2T.     

用功能原理讨论稳定受迫振动

应用功能原理讨论稳定受迫振动,得出受迫振动与强迫力之间的相位差关系式(9),定量讨论了在一周期中速度共振和振幅共振的能量,以及强迫力做功输入能量的阻力做功耗散能量的关系,从而得出了一些有意义的结论.     

Optical focusing feature of single element in 128×128 elements electrically controllable cylindrical liquid crystal lens array

<正>A 128×128 elements cylindrical liquid crystal(LC) lens array with electrically controllable focal length is proposed.The cylindrical LC lens array uses transparent indium tin oxide(ITO) films as electrode,avoiding to affect the optical path operating in the voltage-off status.As the top electrode of the cylindrical LC lens array contacts with LC,the operation voltage root-mean-square(RMS) amplitude can be as low as 1.4 V and the response time is about 20-30 ms.The special optical focusing feature of the cylindrical LC lens array is got.And the focal length of this array is about 60-450μm.     

Experimental investigations of the functional morphology of dragonfly wings

Nowadays, the importance of identifying the flight mechanisms of the dragonfly, as an inspiration for designing flapping wing vehicles, is well known. An experimental approach to understanding the complexities of insect wings as organs of flight could provide significant outcomes for design purposes. In this paper, a comprehensive investigation is carried out on the morphological and microstructural features of dragonfly wings. Scanning electron microscopy （SEM） and tensile testing are used to experimentally verify the functional roles of different parts of the wings. A number of SEM images of the elements of the wings, such as the nodus, leading edge, trailing edge, and vein sections, which play dominant roles in strengthening the whole structure, are presented. The results from the tensile tests indicate that the nodus might be the critical region of the wing that is subjected to high tensile stresses. Considering the patterns of the longitudinal corrugations of the wings obtained in this paper, it can be supposed that they increase the load-bearing capacity, giving the wings an ability to tolerate dynamic loading conditions. In addition, it is suggested that the longitudinal veins, along with the leading and trailing edges, are structural mechanisms that further improve fatigue resistance by providing higher fracture toughness, preventing crack propagation, and allowing the wings to sustain a significant amount of damage without loss of strength.     

工作记忆、中央执行功能与流体智力的关系分析

探讨工作记忆、中央执行功能子成分与流体智力的关系.以秦巴山区18～40岁健康成人为研究对象,通过对中央执行功能子成分、工作记忆广度以及流体智力的测量,分析了各变量之间的关系,并进一步探讨了中央执行功能各子成分的可分离性.得到 （1）工作记忆中的中央执行功能具有可分离性;（2）工作记忆广度与瑞文测验成绩之间的显著相关是刷新功能的作用;（3）相对于抑制功能和转换功能,刷新功能对流体智力具有更强的预测效应和解释力.     

Thermal Buckling Analysis of FGM Sandwich Circular Plates Under Transverse Nonuniform Temperature Field Actions北大核心CSCD

Based on the von Kármán geometric nonlinear plate theory, the displacement⁃type geometric nonlinear governing equations for FGM sandwich circular plates under transverse nonlinear temperature field actions were derived. With the immovable clamped boundary condition, the analytical formula for dimensional critical buckling temperature differences of the system was obtained from the solution of the linear eigenvalue problem. Moreover, the 2⁃point boundary value problem of ordinary differential equations was solved with the shooting method. The effects of geometric parameters, constituent material properties, gradient indexes, temperature field parameters and layer⁃thickness ratios on the critical buckling temperature differences, the thermal postbuckling equilibrium paths, and the buckling equilibrium configurations of FGM sandwich circular plates, were investigated. The results show that, with the increases of the thickness⁃radius ratio, the relative thickness of the FGM layer and the gradient index, the FGM sandwich circular plate's critical buckling temperature difference will increase monotonically. Given a fixed radius and a fixed total thickness, the postbuckling deformation of the FGM sandwich circular plate will decrease significantly with the relative thickness of the FGM layer. © 2023 Editorial Office of Applied Mathematics and Mechanics. All rights reserved.     

Phase imaging with rotating illumination

A modified extended-ptychographical-iterative-engine （ePIE） algorithm is proposed to overcome the dis- advantages of ePIE technique and reduce the influence of stage hysteresis or backlash error. The exit wave of a rotatable ＂screen＂ illuminated by plane wave is used as the illumination on the specimen, and the complex transmission functions of the rotatable object and specimen can be simultaneously reconstructed. Compared with the standard x - y scanning PIE algorithm, the proposed algorithm can completely avoid the influence of stage hysteresis （or backlash error）. The proposed algorithm also has higher convergence s!oeed and better accuracy than the standard PIE algorithm.     

德国完成可印刷OLED研究可实现经济化生产

经过5年的研究,德国联邦教育与研究部（BMBF）资助的500万欧元印刷OLED项目（PrintOLED）近日成功完成。该项目作为＂有机电子＂尖端集群的组成部分,成功从溶液中开发出大面积、均匀的有机功能材料涂层。相比传统的真空蒸发工艺带来的高材料消耗而言,研究中采用的印刷工艺（包括凹版印刷、喷墨印刷和狭缝式挤出涂布等）可实现OLED和有机太阳能电池的经济化生产。     

静息态功能磁共振成像评估健康老年人认知行为的多尺度熵模型研究

当前,静息态功能磁共振成像(rfMRI)为脑功能检测提供了高效、快捷的先进技术.熵可以捕捉神经信号动态特征,可作为量化评估参数,但尚存在固定尺度计算缺陷且对认知行为的生物学标记少有研究,影响检测精准性.为此,本文将多尺度熵模型与机器学习方法联合,寻求BOLD信号复杂度表征健康老年人认知分数的功能影像学标记.由扫描前认知量表测试分数将98名健康老年人分为优、差两组,78名纳入训练,20名纳入测试.首先,构建多尺度熵模型,计算两组扫描数据熵,统计和对比以优化模型参数;然后,在优化参数下由统计显著性高的脑区熵值构建特征向量;最后,用极限学习机对两组分类并统计检验.发现:rfMRI多尺度熵在评估老年人认知分数时,在额、颞叶脑区存在较大显著性差异,以此为标记区分认知分数可达80%准确率.结论:额、颞叶等脑区优化的多尺度熵可有效区分健康老年人认知行为优劣.该研究将为rfMRI替代主观繁琐的传统认知量表测试提供新的检测参数和新方法.     

Control system for the CSNS ion source test stand

A penning plasma surface H- ion source test stand for the CSNS has just been constructed at the IHEP. In order to achieve a safe and reliable system, nearly all devices of the ion source are designed to have the capability of both local and remote operation function. The control system consists of PLCs and EPICS real-time software tools separately serving device control and monitoring, PLC integration and OPI support. This paper summarizes the hardware and software implementation satisfying the requirements of the ion source control system.