《回望人类发明之路》连载之十一 近代科学诞生(下)

近代科学的诞生,成为人类发明活动的分水岭。古往今来,人类渴望了解自己,这既出于治疗疾病的需要,又源于解开生命之谜的强烈内心需求。然而,了解人类自身比洞察身外的事物困难得多,因为生命过程极为隐秘复杂,而人类出于天性,不情愿解剖同类的遗体。在漫长的欧洲中世纪,     

基于DSP控制的显微系统

目前,在生物学、医学、微电子制造行业等领域都迫切需要一种新型的显微系统来改善当前效率较低的现状,并降低其在检测过程中的成本。本论文论述了一种基于DSP控制的新型显微系统,综合了CCD图像传感器的特点,以及DSP高速,实时响应强等的优点。这种基于DSP系统智能控制的显微系统把需要检测的目标物体通过光学显微镜放大成实物像,该像进入CCD光靶面。CCD将光信号转化为电信号,并将此模拟信号由图像采集卡采集后,转化为数字信号后通过DSP微处理器进行图像分析后,实现自动调焦获取最清晰的图像,并将采集到的图像处理后输出到显示屏上。它的便携性,高稳定性,以及高效率性,使其成为将来显微系统在生物、医学以及工业等检测应用的发展主流。     

High resolution imaging using scanning ion conductance microscopy with improved distance feedback control

Microscopy is an essential technique for observation on living cells. There is currently great interest in applying scanning probe microscopy to image-living biological cells in their natural environment at the nanometer scale. Scanning ion conductance microscopy is a new form of scanning probe microscopy, which enables non-contact high-resolution imaging of living biological cells. Based on a scanned nanopipette in physiological buffer, the distance feedback control uses the ion current to control the distance between the pipette tip and the sample surface. However, this feedback control has difficulties over slopes on convoluted cell surfaces, which limits its resolution. In this study, we present an improved form of feedback control that removes the contribution of up to the third-order slope from the ion current signal, hence providing a more accurate signal for controlling the distance. We show that this allows faster and lower noise topographic high-resolution imaging.     

[210]cub切型弛豫铁电单晶PMN-32PT电畴研究

利用偏光显微镜研究了电场对弛豫铁电单晶PMN-32PT电畴组态的影响．结果表明,对于[210]cub切型单晶,当施加的电场强度为0kV·cm^-1时,透明区域呈三方畴形态;当施加电场强度为6kV·cm^-1时,诱导出单斜相;但继续增加电场强度至10kV·cm^-1时,晶体没有呈现单斜相的单畴形态,亦无其他相变;此后,将电场强度减小至5kV·cm^-1时,单斜相消失,说明该单斜相是亚稳态的．     

导电原子力显微镜在介质薄膜电流图像检测中产生的假像

对导电原子力显微镜在介质层电流图像检测中存在的假像进行了研究。发现这种假像归因于导电探针针尖较大的直径,其大小与被检测样品表面的缺陷点、漏洞、沟穴大小相关。研究表明,为提高图像分辨率,避免检测过程中存在的假像,需要使用具有纳米直径针尖的超尖导电探针。     

预防医用显微镜霉变和自然氧化的探讨

显微镜是一种贵重精密仪器,最容易发生镜片霉变,镜身自然氧化,使显微镜无法正常使用。该文从产生这一现象的原因着手,提出显微镜养护措施,从而达到延长显微镜使用寿命的目的。     

倒置式金相显微镜的操作规程与实践教学

实用的倒置式金相显微镜操作规范,可以保证显微观察的效果,也利于设备保护。但是,更重要的是规程背后包含更加丰富的内容,这才是显微镜操作过程中需要深入了解的。本文介绍了倒置式金相显微镜的操作规程,规程细节的详细分析,以及在实践教学中的应用、维护。     

激光共聚焦显微镜的使用和管理

阐述了LEICA TCS SP5共聚焦显微镜的组成、工作原理、样品制备方法,提出了该激光扫描共聚焦显微镜的日常维护和管理方法。     

微波诱变高产L-乳酸细菌的选育与表征

采用带水循环冷却器的微波装置,在低功率微波条件下,对干酪乳杆菌鼠李糖亚种（Lactobacillus casei subsp．rhamnosus）X1—12进行诱变处理,在微波功率为400W、辐射时间3min的诱变条件下得到一突变菌株W4-3-9,其L-乳酸产量为115．8g／L,比原始菌株X1-12提高了58．0％,连续遗传10代,产酸性状稳定．采用原子力显微镜（AFM）对未辐射的原始菌株和高产酸的突变菌株的表面形态和DNA进行观察对比,获得了微波辐射前后干酪乳杆菌的细胞表面形态和DNA的AFM图像．     

Numerical surface characterization of wear debris from artificial joints using atomic force microscopy

Study on surface features of wear particles generated in wear process provides an insight into the progress of material failure of artificial joints. It is very important to quantify the surface features of wear particles in three dimensions. In this study, a new approach using atomic force microscopy was proposed to carry out 3D numerical surface characterization of wear debris generated from artificial joints. Atomic force microscopy combined with image processing techniques was used to acquire appropriate 3D images of wear debris. Computerized image analysis techniques were then used to quantify surface texture features of wear debris such as surface roughness parameters and surface texture index. The method developed from the present study was found to be feasible to quantity the surface characterization of nanoand micro-sized wear debris generated from artificial joints.