光镊技术在单细胞和单分子特性检测中的研究进展

光镊是一种高分辨率的光学操控技术,自诞生以来就广泛应用于生物研究领域,对单细胞和单分子的相关研究起了关键作用.随着近些年对光镊技术的不断改进,一些新方法已经用于单细胞和单分子的研究.综述了近些年光镊在单细胞操控、细胞间相互作用、红细胞力学特性研究领域的最新进展和光镊技术在单分子特性检测中的最新应用成果,以及光镊拉曼技术和光镊结合微流控技术的最新应用实例.最后,分析了光镊目前的发展现状并对光镊技术未来的发展提出了展望分析.     

激光双光镊在单分子生物物理中的研究进展

光镊采用聚焦的激光束束缚微米、纳米级的粒子，具有亚皮牛级的力分辨率和亚毫秒级的时间响应，在单分子生物物理中具有广泛的应用。通过化学耦链将生物大分子连接到高分子微球上，光镊可以测量大分子的伸长以及受力，进而研究DNA-蛋白质相互作用、蛋白质折叠及分子马达机械化学性质等动态过程。简要介绍光镊的基本原理和常见的单分子光镊几何构型，并以双光镊为例，介绍如何设计和搭建光镊设备、所涉及的技术原理、稳定性与降噪处理方法以及分辨率测试方法。以国家蛋白质科学研究（上海）设施的双光镊实验装置为例，论述双光镊在单分子生物物理中的应用及进展。最后，对单分子光镊技术的发展前景作出展望。     

光镊技术的研究现况

光镊技术是激光技术的重大发明,能利用光的动量与物质相互作用产生光势阱效应,已成为微纳米微粒操控和皮牛顿力测量的重要工具。光镊技术不仅丰富和推进了光学领域的发展,也为光学与多学科的交叉融合架起了一座桥梁,彰显出了它独特而不可替代的作用。综述回顾了30年来光镊理论和技术的发展,系统梳理了光镊在细胞生物学、单分子生物学、软物质胶体科学以及物理纳米科学等领域的应用,并列举典型的应用实例,探讨了光镊技术应用的特点,展望了光镊技术应用蓬勃发展的美好未来。     

单模光纤微探头式光镊技术

通过对平端面和基于半球形自透镜端面的单模光纤微型探头光镊技术的研究．表明单模光纤微型探头式光镊系统结构简单、捕陷范围大、操纵灵活,可以适应更多的生物细胞和生物分子的光微操作需求．扩大了激光微操纵技术在生命科学中的应用范围。     

单细胞和单分子的激光捕获及喇曼光谱分析

上海光机所在“单细胞和单分子的激光捕获及喇曼光谱分析”项目中研制出了激光镊子喇曼光谱仪，可探测喇曼光谱范围为330-960nm，光谱分辨率水平为7cm^-1，探测灵敏度达到可以探测到单个生物细胞喇曼光谱的水平。完成了利用脉冲激光梯度力使得粘在样品池底面的样品颗粒从底面离开，从而可以被光镊捕获的实验，并采用合理的物理模型解释了实验现象。利用激光捕获喇曼光谱技术开展了环境温度变化对单个酵母细胞的分子喇曼光谱影响的研究；     

利用飞秒激光光镊捕获生物细胞

采用自行搭建的飞秒激光光镊,实现了对人体血红细胞（RBC）的稳定捕获。使用的光源为自行搭建的掺钛蓝宝石克尔透镜锁模激光器,输出中心波长810nm、脉冲宽度40fs和重复频率为100MHz的飞秒激光脉冲。通过实验比较了飞秒激光光镊和连续（CW）激光光镊的捕获能力,依据实验数据,比较了两者的Q值。实验结果显示,飞秒激光光镊对于捕获生物细胞同样有效,将光镊技术和飞秒激光特性相结合用于生物学研究领域会有很好的应用前景。     

红外半导体激光光镊的实验研究

激光光镊技术是一项在许多科学领域有广阔应用前景的技术。本文详细给出构建一台红外半导体激光光镊的设计思想及实例。由于采用了独特的对大功率多模红外激光选模整形和双透镜陷阱操纵技术等性能价格最优化选择 ,该系统易于构建 ,陷阱操作方便 ,其构建价格仅一般光镊的几十分之一 ,非常适合光镊技术的推广和一般实验室构建     

飞秒激光诱导细胞融合技术的实验研究

细胞融合是细胞工程中的一项重要技术手段。传统细胞融合采用电脉冲、化学融合剂或病毒法实现，这些方法或融合率极低或对融合细胞毒性较大。紫外纳秒激光脉冲与光镊相结合诱导细胞融合为细胞生物学提供了一种单细胞操作，实现细胞融合的手段，但纳秒激光对细胞的热损伤较大。飞秒激光具有单脉冲能量小（nJ），峰值功率密度极高的特点。在生物学应用中，其时空分辨率高等优点被广泛应用于细胞手术、基因转染等研究领域。我们利用飞秒激光为光源实现了集光镊与细胞手术为一体的飞秒激光细胞显微操作系统。利用该系统，实现飞秒激光诱导细胞融合。该成果有望成为单细胞操作实现高效细胞融合的技术手段。     

四象限光电探测器在激光光学系统中的典型应用分析

分析了四象限光电探测器在激光制导、光镊、扫描探针显微镜和空间光通信等激光光学系统中的典型应用。结果表明,四象限光电探测器应用在激光制导中具有高制导精度的优势;应用在光镊系统和扫描探针显微镜中具有纳米级分辨率：应用在空间光通信中具有较高跟踪和定位精度。     

一种用于生物研究的光镊与激光微束系统

分析光镊与激光微束的性质和特点,研究两者相互配合、联合操作的技术及优势。在国内首次实现光镊与微束激光的耦合技术,这种全新的显微操作系统可对活体细胞进行全方位操作与微加工。     

数字式单边带混频

本文主要分析用正交信号实现单边带混频电路,并阐述其优越性.     

Bright CdSe quantum dot inserted in single ZnSe nanowires

We report the evidence of CdSe quantum dot (QD) insertion in single defect-free ZnSe nanowire. These nanowires have been grown by molecular beam epitaxy in vapour-liquid-solid growth mode catalysed with gold particles. We developed a two-step process allowing us to grow very thin (from 15 to 5 nm) defect-free ZnSe nanowire on top of a nanoneedle, where all defects are localised. The CdSe QDs are incorporated to the defect-free nanowires part. Owing to the extraction efficiency of the nanowires and the reduced number of stacking fault defects in the two-step-process nanowires, a very efficient photoluminescence is observed even on isolated single nanowire. Time-resolved photoluminescence and correlation photon give evidences that the bright photon emission is related to the CdSe QD.     

Design and simulation of a nanoelectronic single electron 2-4 decoder using a novel simulator

The design and simulation of a single-electron 2-4 decoder using a novel single electron circuit simulation tool named single-electron circuit simulator (SECS), is presented in this paper. In single electron circuits bits of information are represented by the presence or absence of single electrons at conducting or semiconducting islands. SECS utilizes the Monte Carlo method and the change in free-energy of the whole circuit determines the tunnel rates of possible tunnel events, providing thus a real time simulation of any arbitrary single-electron circuit. Furthermore, SECS is using the SPICE interface for schematic capture. SPICE models of single-electron circuit structures have been developed and, therefore, SECS can also be used for the design and simulation of hybrid microelectronic—single-electron circuits.     

On modelling and characterization of single electron transistor

As the nanotechnology rose to the surface, single electron transistor (SET) was invented. In contrast to the well-known response of MOS current, SET current has peaks at certain gate voltages, which disappears at other gate voltages. The SET has promised to be valuable in many applications for its high speed and low power consumption. First, a comparison was drawn between different models of SET based on the orthodox theory. Such theory explains electron transport from source to drain, employing free energies, tunnel rates and coulomb blockade phenomenon, in addition to quantizing electron tunnelling. Afterwards, a simplified model was proposed to account for unnecessary lengthy calculation processes, resulting from the large number of states assumed for simulation. The proposed PSPICE simplified model was confirmed by comparing its results to the results of the available models, and it was found to agree well with them. Taking much less runtime than the available models, the proposed model can easily be used to simulate SET-based integrated circuits on PSPICE.     

TMS 32020单片信号处理器在测控系统中的应用

在卫星地面测控系统中,要求在低信噪比(如-20分贝)条件下提取目标的多普勒频率信息,以引导接收机锁相环捕获信号并锁定。模拟式频率引导采用经典的晶体滤波器组,其数量大、成本高、重量体积大。数字式频率引导采用对接收信号采样序列进行FFT运算处理实现对目标的频率捕获,具有显著的优越性。作者等人以8086微机实现的数字频率引导设备已成功地应用于同步通讯卫星测控站中。为了进一步提高处理速度,采用了TMS32020单片信号处理器研制出频率引导快速处理机,使频率引导处理时间提高15倍以上。该成果的硬件设备可适应不同的实时数字信号处理要求,应用于雷达、通讯、遥控、仪器、语音、智能等各种场合。     

Modeling single event crosstalk speedup in nanometer technologies

With advances in CMOS technology, circuits become increasingly more sensitive to transient pulses caused by single event (SE) particles. In addition, coupling effects among interconnects can cause SE transients to spread electronically unrelated circuit paths which may increase the SE Susceptibility of CMOS circuits. The coupling effects among interconnects need to be considered in single event modeling and analysis of CMOS logic gates due to technology scaling effects that increase both SE vulnerability and crosstalk effects. This work reports on the signal speedup effects caused by SE crosstalk and then proposes a best-case delay estimation methodology for use in design automation tools for the first time to our knowledge. The SE coupling speedup expressions derived show very good results in comparison to HSPICE results. Results show an average error of about 8.42% for best-case delay while allowing for very fast analysis in comparison to HSPICE.     

单电源模拟设计技术及虚地发生器的应用

对单电源模拟电路设计中的核心部件单纯源放大器进行了分析并提出几点应注意的问题;介绍了TI公司的虚地发生器（TLE2425/2426）在单电源模拟电路设计中的应用,并与一般的电压参考进行了比较。     

基于单片机的多点无线温度监控系统

随着经济发展信息科学技术与微电子技术也得到了很大的推动,对于温度进行监控的手段,也随着现代科学技术的发展做到温度的自动化与智能化的监控。单片机的多点无线温度控制就是在此基础上进行开发设计的。本文主要对单片机进行设计时的无线传输模块进行温度监控检测系统的应用进行分析,对于温度的调节范围与其温度超过标准后进行报警的办法进行分析与研究。     

Efficient single layer RGB phosphorescent organic light-emitting diodes

We report efficient single layer red, green, and blue (RGB) phosphorescent organic light-emitting diodes (OLEDs) using a “direct hole injection into and transport on triplet dopant” strategy. In particular, red dopant tris(1-phenylisoquinoline)iridium [Ir(piq)₃], green dopant tris(2-phenylpyridine)iridium [Ir(ppy)₃], and blue dopant bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium [FIrpic] were doped into an electron transporting 1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBi) host, respectively, to fabricate RGB single layer devices with indium tin oxide (ITO) anode and LiF/Al cathode. It is found that the maximum current efficiencies of the devices are 3.7, 34.5, and 6.8 cd/A, respectively. Moreover, by inserting a pure dopant buffer layer between the ITO anode and the emission layer, the efficiencies are improved to 4.9, 43.3, and 9.8 cd/A, respectively. It is worth noting that the current efficiency of the green simplified device was as high as 34.6 cd/A, even when the luminance was increased to 1000 cd/m² at an extremely low applied voltage of only 4.3 V. A simple accelerated aging test on the green device also shows the lifetime decay of the simplified device is better than that of a traditional multilayered one.     

单训练样本条件下的人脸识别算法研究

由于主成分分析法和线性判别分析法等传统方法对单训练样本的识别能力弱,甚至直接失效。本文提出了二维小波变换与矩阵的最大间距准则或矩阵的线性判别分析相融合的人脸特征提取算法。即首先将原图像进行三层二维小波变换,然后对每层的近似分量分别进行最大间距准则或线性判别分析处理,最后用欧氏距离判别。在ORL人脸数据库上取得的实验结果表明,本文提出的算法能够提高单训练样本条件下的人脸识别率,同时也满足实时性要求。