Correlation between microbubble-induced acoustic cavitation and hemolysis in vitro

Microbubbles promise to enhance the efficiency of ultrasound-mediated drug delivery and gene therapy by taking advantage of artificial cavitation nuclei.The purpose of this study is to examine the ultrasound-induced hemolysis in the application of drug delivery in the presence of microbubbles.To achieve this goal,human red blood cells mixed with microbubbles were exposed to 1-MHz pulsed ultrasound.The hemolysis level was measured by a flow cytometry,and the cavitation dose was detected by a passive cavitation detecting system.The results demonstrate that larger cavitation dose would be generated with the increase of acoustic pressure,which might give rise to the enhancement of hemolysis.Besides the experimental observations,the acoustic pressure dependence of the radial oscillation of microbubble was theoretically estimated.The comparison between the experimental and calculation results indicates that the hemolysis should be highly correlated to the acoustic cavitation.     

PCB的抗干扰设计

本文以印制电路板的电磁兼容性为研究对象,分析了电磁干扰产生机理,并详细介绍了PCB布局,布线设计中减少电磁干扰的原则,这些措施可确保PCB设计的成功实现。     

高准确度低压电压互感器误差分析

高准确度低压电压互感器是用于计量部门、电业部门、科研单位开展精密电能表、电气指示仪表和低压电压互感器的传递校验以及进行电压、功率和电能的精密测量所需用的仪器。     

崇明岛的大梦想

正生态文明就是在约束条件下的一种均衡论,在保护中发展,在发展中求保护,在摸索中寻求适合崇明发展的产业。东海瀛洲,是崇明岛美丽的古称。相传在远古东海之中有一瀛洲侧境,是神仙居处,秦始皇和汉武帝先后派人到东海之上四处寻找,都没有找到。而到了明朝,朱元璋则把"东海瀛洲"四个字赐给了崇明岛。瀛,海也。崇明岛东南濒东海,西南与上海宝山、江苏     

中国信息安全产业的中坚力量——记国家信息安全工程技术研究中心

信息安全,顾名思义,就是使信息网络的硬件、软件及其系统中的数据受到保护,不受偶然的或者恶意的原因而遭到破坏、更改、泄露,系统能连续、正常、安全的运行,使信息服务保持不中断。它是一门涉及计算机科学、网络技术、通信技术、密码技术、信息安全技术、应用数学、数论、信息论等多种学科的综合性学科。     

基于时间反转的骨裂纹超声成像模拟研究

提出了一种结合超声非线性和时间反转技术进行长骨中裂纹成像的技术。骨裂纹的超声散射信号中包含非经典非线性成分。从时反阵列接收的探测信号中,经滤波得到三次谐波;然后利用时间反转技术来对裂纹区域进行聚焦成像。在计算机仿真实验中,基于Preisach-Mayergoyz(PM)模型模拟了单个及两个骨裂纹产生的非线性信号,实现了时间反转的非线性成像,并讨论了裂纹的深度位置对成像结果的影响。该方法为骨裂纹的超声无损检测提供了一种新技术。     

超声多普勒检测动脉内出血的多维度复合模型研究

建立检测内出血点的量化技术有助于进一步提高超声止血的效率。提出了描述动脉血管内出血的多维度复合模型。由一个描述破裂血管的二维模型和一个描述下游血管系统响应的一维模型组成。计算机仿真及初步的活体实验结果证明了理论模型的有效性,并表明内出血时的血流速度波形会产生大幅度单波峰或收缩速度峰的相位延迟,该结果可作为自动快速检测血管破裂的量化参数。     

Graphene/SrTiO_3 interface-based UV photodetectors with high responsivity

Strontium titanate(SrTiO3),which is a crucial perovskite oxide with a direct energy band gap of 3.2 eV,holds great promise for ultraviolet(UV)photodetection.However,the response performance of the conventional SrTiO3-based photodetectors is limited by the large relative dielectric constant of the material,which reduces the internal electric field for electron-hole pair separation to form a current collected by electrodes.Recently,graphene/semiconductor hybrid photodetectors by van-der-Waals heteroepitaxy method demonstrate ultrahigh sensitivity,which is benefit from the interface junction architecture and then prolonged lifetime of photoexcited carriers.Here,a graphene/SrTiO3 interface-based photodetector is demonstrated with an ultrahigh responsivity of 1.2×106 A/W at the wavelength of 325 nm and～2.4×104 A/W at 261 nm.The corresponding response time is in the order of～ms.Compared with graphene/GaN interface junctionbased hybrid photodetectors,～2 orders of magnitude improvement of the ultrahigh responsivity originates from a gain mechanism which correlates with the large work function difference induced long photo-carrier lifetime as well as the low background carrier density.The performance of high responsivity and fast response speed facilitates SrTiO3 material for further efforts seeking practical applications.     

Kinetic studies on the single electron transfer reaction between 2, 2, 6, 6-tetramethylpiperidine oxoammonium ions and phenothiazines: the application of Marcus theory

Electron transfer reactions take place readily between 2, 2, 6, 6-tetramethylpiperidine oxoammonium ions (1a, 1b) and phenothiazines (2a—2g), giving corresponding nitroxides (3a, 3b) and phenothiazine radical cations (4a—4g). The rate constants for the electron self-exchange reactions between 1 and 3, as well as between 2 and 4, are determined by EPR and ~1H NMR line-broadening effect in acetonitrile. By application of the Marcus theory, the kinetics of the cross-exchange reactions between 1 and 2 is studied.     

用于活体温度评估的非线性超声热应变模型

热疗在肿瘤消融、高血压治疗等方面有重要应用价值.对热疗过程进行温度监控有利于实施合理的治疗规划,同时可提高治疗的安全性、减少副作用.利用基于超声回波偏移的热应变测温理论进行二维温度估计是一种常用的超声测温方法.但该理论基于组织热膨胀及声速随温度线性变化的假设,适用的温度测量范围一般限于37℃～50℃.该文基于升温组织的...