Differentiating bulk nanobubbles from nanodroplets and nanoparticles

History has shown that it is not as easy as one might think to differentiate between bulk nanobubbles and nanodroplets or nanoparticles. It is generally easy to detect colloids (i.e. something that looks different, e.g. scatters light differently than its surrounding solvent), but less easy to determine the nature of these colloids. This has led to misinterpretations in the literature, where nanodroplets or nanoparticles have mistakenly been assumed to be nanobubbles. In this paper, we review a multitude of experimental methods and approaches to prove the existence of bulk nanobubbles. We conclude that combinations of optical detection with physical perturbations such as pressure or ultrasound, or phase-sensitive holographic methods are the most promising and convenient approaches.     

基于眼动追踪技术的高中生化学问题解决的差异性研究——以“氧化还原反应”为例

以氧化还原反应相关试题作为测试材料,采用眼动追踪技术对12名高一学生进行3(学业水平)*3(试题难度)两因素混合实验,实验结束后进行追述性口语报告。结果表明,在氧化还原反应问题解决过程中学优生信息加工速度快、深度浅、难度小,采用正向加工和逆向排除结合的策略。学中生信息加工速度慢、深度深、难度大,采用正向加工策略。学困生轻易放弃,信息加工无效。随着问题难度的增大,学生信息加工速度变慢、深度变深、难度变大。     

基于ZigBee网络和超声定位的智能跟随小车

基于成熟的IEEE802.15.4协议和ZigBee无线模块,结合超声定位,设计了一种新颖的智能跟随系统。设计的核心为PIC18F4620单片机和MRF24J40MA无线收发模块,通过无线收发来完成节点间的识别与同步,同时以超声测距系统完成对被跟踪目标的定位,通过控制驱动电机动作实现对指定目标的定距离跟随。控制网络以子网的形式控制不同系统的分时定位跟随,同时管理各移动定位系统的入网和切换。样机测试结果表明系统达到了预期的跟随设计要求,具有一定的工程使用价值。     

三维斑点追踪成像评价甲状腺功能亢进患者左心室收缩功能改变的应用价值

目的 探讨三维斑点追踪成像（3D-STI）技术在评价甲状腺功能亢进(甲亢)患者左心室整体收缩功能中的应用价 值。方法 选择50 例甲状腺功能亢进患者与45 例健康志愿者,获取心尖四腔心切面动态图像,存储左心室三维全容积动态图像后,运用3D-STI 软件进行脱机分析,得到两组收缩期左心室整体纵向峰值应变（GLS）、圆周峰值应变（GCS）、左心室扭转度角度峰值(LV-tw)、左心室扭力（LV-tor）、左心室心底水平旋转角度峰值（Prot-B）、左心室心尖水平旋转角度峰值（Prot-A）及左心室射血分数（LVEF）等,比较两组三维应变（3DS）指标之间的差异。结果 与正常对照组比较,甲亢组的左心室收缩功能增强,GLS、GCS 分别为（-20.47±3.08）% vs.（-18.52±4.77）%、（-28.98±3.00）% vs.（-25.88±2.12）%,两组差异均有统计学意义（均P＜0.05）;甲亢组LV-tw、LV-tor、LVProt-A、LVProt-B 均较正常对照组略有增加,但差异均无统计学意义（均P＞0.05）。结论 3D-STI 可无 创、敏感检测甲亢患者左心室三维应变,为临床客观评估甲亢左心室收缩功能提供一种新方法。     

Cell Tracking with Caged Xenon: Using Cryptophanes as MRI Reporters upon Cellular Internalization

Caged xenon has great potential in overcoming sensitivity limitations for solution‐state NMR detection of dilute molecules. However, no application of such a system as a magnetic resonance imaging (MRI) contrast agent has yet been performed with live cells. We demonstrate MRI localization of cells labeled with caged xenon in a packed‐bed bioreactor working under perfusion with hyperpolarized‐xenon‐saturated medium. Xenon hosts enable NMR/MRI experiments with switchable contrast and selectivity for cell‐associated versus unbound cages. We present MR images with 10³‐fold sensitivity enhancement for cell‐internalized, dual‐mode (fluorescence/MRI) xenon hosts at low micromolar concentrations. Our results illustrate the capability of functionalized xenon to act as a highly sensitive cell tracer for MRI detection even without signal averaging. The method will bridge the challenging gap for translation to in vivo studies for the optimization of targeted biosensors and their multiplexing applications.     

In Situ Pyrolysis Tracking and Real-Time Phase Evolution: From a Binary Zinc Cluster to Supercapacitive Porous Carbon

The in situ tracking of the pyrolysis of a binary molecular cluster [Zn₇(μ₃-CH₃O)₆(L)₆][ZnLCl₂]₂ is presented with one brucite disk and two mononuclear fragments (L=mmimp: 2-methoxy-6-((methylimino)-methyl)phenolate) to porous carbon using TG-MS from 30 to 900 °C. Following up the spilled gas product during the decomposed reaction of zinc cluster along the temperature rising, and in conjunction with XRD, SEM, BET and other materials characterization, where three key steps were observed: 1) cleavage of the bulky external ligand; 2) reduction of ZnO and 3) volatilization of Zn. The real-time-dependent phase-sequential evolution of the remaining products and the processing of pore forming template transformation are proposed simultaneously. The porous carbon structure featuring a uniform nano-sized pore distribution synthesized at 900 °C with the highest surface area of 1644 m² g⁻¹ and pore volume of 0.926 cm³ g⁻¹ exhibits the best known capacitance of 662 F g⁻¹ at 0.5 A g⁻¹.     

基于毕业学生的信息追踪与反馈机制提高教学管理效率与人才培养质量

学生是教育的受体,学生的意见在推进课程建设、教学改革以及提升人才培养质量等方面具有重要的指导和借鉴意义。秉承立德树人的理念,以服务学生成长发展为核心,育人成果为导向,探讨做好教育的实施主体和接受主体之间互相反馈的机制和模式,对不断推动教学改革向高效率和高质量方向发展具有重要意义。着重探讨了化学学院做好毕业生信息追踪的具体路径和意见反馈模式。     

灰度人脸识别形态学相关的一般理论研究

提出一般形态学相关概念,并提出一种小型联合变换相关器的硬件设计以实现一般形态学相关.提出两种改进的一般形态学相关算法,灰度图像按某种分解方法分解成一系列二值图像片.在第一种算法中,每片二值联合图像片的边缘被检测,其功率谱求和.在第二种算法中,一种情况是每片的联合变换功率谱被二值化或细化再求和;另一种情况是这些片的联合变换功率谱的总和被二值化或细化.计算机模拟结果表明,改进后的算法能改善高相似度灰度人脸图像识别的鉴别率.     

湍流大气传输中跟踪抖动对远场影响的仿真研究

分析了跟踪抖动对湍流大气传输远场光斑的影响。基于麦克斯韦电磁场理论,采用大气相干长度对大气湍流进行描述,推导了发射光束因跟踪抖动导致光轴偏离的远场表达式。在此基础上,利用相位屏法模拟抖动引起的倾斜相位和大气折射率起伏引起的相位调制,并采用低频补偿的功率谱反演法对传输过程进行了数值仿真。分析了不同跟踪抖动、湍流强度条件下远场光斑质心脱靶量的变化,以及不同尺寸模拟目标的回波概率。分析结果表明,在传输距离为10 km时,强湍流造成的远场光斑脱靶量可达几十μrad;当跟踪抖动较大时,湍流强弱对脱靶量影响差别很小。最后,对一定尺寸的模拟目标,从探测回波概率的角度给出了发射系统跟踪抖动量的控制范围。