基于主动式时间反转镜的声呐目标强度测量研究

为提高目标强度测量过程中的抗噪声、混响以及浅海多途干扰性能,从军标文件中的目标强度测量方法以及主动式时间反转镜的基本原理出发,经过研究和推演,发现可将基于单阵元的主动式时间反转镜与相关器结合应用于目标强度测量过程,提出了一种新的目标强度测量方法。该方法利用了主动式时间反转镜的抗多途特性,使得测量具有抗多途的性能;利用噪声与信号的不相关特性,算法结合相关器起到了很好的抗随机噪声效果;混响中的体积混响是随机的,算法具有抗体积混响的性能。论文分别从理论仿真和水池实验验证了算法的有效性和正确性。     

室内环境中脑控轮椅的路径跟踪控制

为了实现室内环境中脑控轮椅的自主导航,提出了一种简单有效的路径跟踪控制方法。给定的路径通常被表示为一系列离散点,根据这一特点,提出了分段直线路径跟踪方法,即依次跟踪由前后两个路径点构成的直线路径到达目标点。基于预瞄点技术并结合模糊算法和传统的PID控制方法设计控制器,完成各分段直线路径的跟踪,并给出了有效的切换条件。实验结果表明,本文提出的路径跟踪控制方法能够使脑控轮椅在室内环境中精确地跟踪给定路径。     

Rapid analysis of phthalic acid esters in environmental water using fast elution gas chromatography with mass spectrometry and adaptive library spectra

A method for the fast determination of the components in a complex sample by using gas chromatography with mass spectrometry was developed and used for the quantitative analysis of phthalic acid esters in environmental water. In the method, the adaptively corrected mass spectra were used to compensate for the differences between the library spectra and the measured ones in the experiment. The correction was obtained by the iterative transformation of the library spectra using iterative target transformation factor analysis, and the resolution was performed by non‐negative immune algorithm using the corrected spectra. Rapid analysis of 16 phthalic acid esters in water samples was achieved using fast elution gas chromatography with mass spectrometry measurements. The results show that the mass spectra and chromatographic profiles of the phthalic acid esters can be obtained from the overlapping signal of 13 min elution, and accurate quantitative analysis can be obtained. The recoveries of the phthalic acid esters obtained by standard addition are between 90.3 and 107.4%, and the relative standard deviations obtained in repeated measurements are less than 9%.     

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.     

Synthesis and characterization of folic acid‐modified carboxymethyl chitosan‐ursolic acid targeted nano‐drug carrier for the delivery of ursolic acid and 10‐hydroxycamptothecin

Carboxymethyl chitosan (CMCS), as a water‐soluble, biocompatible, and biodegradable polymer, is an excellent carrier for a sustained drug delivery system. In this study, a amphiphilic carboxymethyl chitosan‐ursolic acid nano‐drug carrier modified by folic acid (FPCU) were prepared, and then the nano‐drug carrier wrapped another anticancer drug 10‐hydroxycamptothecin were self‐assembled into nanoparticles (FPCU/HCPT NPs). The FPCU/HCPT NPs had a suitable size, high drug loading efficiency of ursolic acid (6.4%) and 10‐hydroxycamptothecin (14.1%). The drug release study in vitro indicated that the nanoparticles have obviously sustained effect and pH sensitive behaviors, the drug release amount was higher at pH 5.5 than at pH 7.4. in vitro and in vivo study showed that the nanoparticles displayed a high antitumor efficiency to tumor cells compared with free drug. The nano delivery system as a carrier for ursolic acid (UA) and 10‐hydroxycamptothecin (HCPT) has good application prospects in cancer treatment.     

α-Trifluoromethyl Chalcones as Potent Anticancer Agents for Androgen Receptor-Independent Prostate Cancer

α-Trifluoromethyl chalcones were prepared and evaluated for their antiproliferative activities against androgen-independent prostate cancer cell lines as well as five additional types of human tumor cell lines. The most potent chalcone 5 showed superior antitumor activity in vivo with both oral and intraperitoneal administration at 3 mg/kg. Cell-based mechanism of action studies demonstrated that 5 induced cell accumulation at sub-G1 and G2/M phases without interfering with microtubule polymerization. Furthermore, several cancer cell growth-related proteins were identified by using chalcone 5 as a bait for the affinity purification of binding proteins.     

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。     

基于酶辅助靶标循环的适体传感器灵敏检测中药中黄曲霉毒素B1

该文基于酶辅助靶标循环信号放大策略构建了用于黄曲霉毒素B1(AFB1)高灵敏检测的化学发光适体传感器。以G-四链体/氯化血红素DNA酶为信号分子设计了免标记的适体探针H1-S1和发夹探针H2。适体探针结合目标AFB1,在核酸外切酶I辅助下,触发靶标循环反应产生发夹H1。发夹H1与H2杂交,释放出完整的G-四链体序列,并进一步与氯化血红素结合形成G-四链体/氯化血红素DNA酶。DNA酶通过催化氧化鲁米诺-H2O2化学发光体系产生化学发光信号,实现AFB1的放大检测。在最优实验条件下,化学发光强度与AFB1质量浓度的对数在0.001~100 ng/mL范围内呈良好的线性关系,相关系数(r2)为0.9955,检出限为0.93 pg/mL,回收率为93.7%~107%。该适体传感器操作简单、灵敏度高、特异性好,在黄曲霉毒素污染检测方面具有良好的应用前景。     

地面目标雷达与红外特性数据库构建

为了对地面目标雷达与红外特性测试的各类数据进行统一规范化管理,使其高效应用,分析各类数据的特性及其处理方式,构建了目标特性数据库管理系统;数据库的整体设计中,在数据头和数据文件方案基础上增加了自动跟随数据表编号的路径生成方法,结合了接口式的运作结构,模块化的数据库功能和层次化的数据表结构设计思路;数据库的编制基于Access数据库管理软件和VC++编程软件,通过ADO数据库访问技术加以实现,详细描述了ADO接口的编程步骤,并对本接口不同指针的入库频率和提取效率进行了对比择优;在运行中,提出了主、副数据库移植性管理方法;工作实践验证了目标特性数据库管理系统的可靠性和高效性,为地面目标特性的测试与分析提供了良好的数据支撑。     

An infrared small target detection algorithm based on high-speed local contrast method

Small-target detection in infrared imagery with a complex background is always an important task in remote sensing fields. It is important to improve the detection capabilities such as detection rate, false alarm rate, and speed. However, current algorithms usually improve one or two of the detection capabilities while sacrificing the other. In this letter, an Infrared (IR) small target detection algorithm with two layers inspired by Human Visual System (HVS) is proposed to balance those detection capabilities. The first layer uses high speed simplified local contrast method to select significant information. And the second layer uses machine learning classifier to separate targets from background clutters. Experimental results show the proposed algorithm pursue good performance in detection rate, false alarm rate and speed simultaneously.