A roll film camera for the AEI-EM6 electron microscope

The currently available plate camera for the AEI EM6 and 6B microscopes is inconvenient for the photography of large numbers of serial sections: firstly because it has to be reloaded relatively frequently and secondly because the restricted format of 70 mm film does not allow a large enough field to be examined at low power. The camera described was designed and built in these laboratories to obviate these problems.     

Modification of an EM6G electron microscope for X-ray microanalysis

A dual purpose stage has been constructed for an EM6G 100 kV transmission electron microscope. With this stage the composition of thin films and bulk specimens can be determined by X-ray microanalysis. With thin films a change of specimen cartridge then enables a full analysis of crystal defects in the film to be made using tilt controls incorporated in the stage. Modifications to the stage to reduce background effects in X-ray microanalysis spectra are also described. The alternative use of this system in the bulk analysis of specimens by an X-ray fluorescence technique is also discussed.     

A cold stage for the Philips EM300 electron microscope

A cold stage has been constructed for the Philips EM300 (and EM301) electron microscopes for investigating the structure of frozen-hydrated biological specimens. The stage entails minimal alterations to the instrument and is capable of a resolution better than 10 Å at the normal operating temperature of -120°C. Frozen specimens can be readily exchanged without condensation or warming up, and maintained in the stage over periods of several hours without detectable deterioration.     

CCD显微摄像法测量孔心距

通过对 1 9J型万能工具显微镜进行数码改造 ,建立了用于工件孔心距测量的CCD数码显微摄像系统。讨论了CCD摄像法测量孔心距的基本原理 ,简要介绍其软件系统 ,为工件孔心距的精密测量提供了快速、有效、经济的测量途径。     

An improved double-tilt stage for the AEI EM7 high-voltage electron microscope

Vibration transmitted by the specimen rod of a side-entry stage frequently decreases image resolution, and the length of the rod in the high-voltage electron microscope can make the problem severe. A detachable tip clamped to the translation stage minimizes the effect, but eliminates the rod as a means of tilting. Furthermore, the second tilt mechanism is usually built into the rod. Thus the sample is coupled not clamped to the rod, increasing the effect. The image resolution attainable with our double-tilt stage was 1·5 nm along the rod's axis and 5·0 nm perpendicular to it before modification. An isotropic resolution of 0·5 nm was achieved by attaching the specimen tip to the rod with a flexible coupling and clamping both ends of the tip to the translation ring. The couplings used transmit the torque to rotate the specimen holder but dampen vibration. Ion-pumping the vacuum system with all other pumps off also improved specimen stability.     

原子力显微镜矩形测力臂弹性系数计算方法研究

原子力显微镜测力臂弹性系数的准确性直接影响其测量精度,是仪器标定的一个重要指标。分别运用理论计算方法、动态计算方法和静态计算方法计算原子力显微镜测力臂弹性系数。以矩形测力臂为例,对其进行灵敏度分析,找出影响测力臂弹性系数的参数。分别选取矩形测力臂原始参数值及参数上下极限值,构成3组实验数据。利用上述3种计算方法,分别计算出3组不同参数值的矩形测力臂的弹性系数,然后对这3种计算方法计算所得的弹性系数进行分析并和生产商给出的名义值进行比较,所得结果为原子力显微镜矩形测力臂弹性系数的精确计算提供参考。     

Single-fluorophore imaging with an unmodified epifluorescence microscope and conventional video camera

Single fluorophores in aqueous solution were imaged in real time with a conventional silicon-intensified target video camera connected to an unmodified commercial microscope (IX70, Olympus) with epifluorescence excitation with a high-pressure mercury lamp. Neither a powerful laser nor an extremely sensitive video camera was required. Three experimental systems were used to demonstrate quantitatively that individual, moving or stationary Cy3 fluorophores could be imaged with the microscope: Cy3-gelsolin attached to an actin filament sliding over heavy meromyosin, sliding actin filaments sparsely labelled with Cy3, and heavy meromyosin labelled with one or two Cy3 fluorophores. The results should encourage many laboratories to attempt 'single-molecule physiology' in which the functions and mechanisms of molecular machines are studied at the single-molecule level in an environment where the biological machines are fully active.     

Air-lock system for the transfer of reactive samples to the Philips EM 300S electron microscope

An air-look system has been developed in order to transfer reactive samples under vacuum from any preparation facility to the high-resolution stage of the Philips EM 300S electron microscope. The system has been tested using the highly hygroscopic material strontium chloride prepared in the form of small particles. Based on the shape of the particles and the associated diffraction pattern, it has been shown that the air-lock transfer system effectively prevents hydration in the case of small SrCl(2) particles.     

Combined CBED and HREM in a philips EM400T analytical electron microscope

The two methods - Convergent Beam Electron Diffraction, and High Resolution Electron Microscopy - provide complementary information about crystalline material. However, the electron optical requirements are conflicting and cannot be optimally fulfilled in a single microscope. This paper shows how an adequate compromise can be found which allows application of both methods in one microscope.     

应用双排TDI CCD提高空间推扫遥感相机动态范围

考虑空间相机观测场景的动态范围很大,本文提出了采用双排时间延迟积分(TDI)CCD来提高相机动态范围的方案。对两排TDI CCD分别设置不同的积分级数。得到的积分级数高的CCD图像虽然可能存在饱和区域,但暗区域极易分辨;积分级数低的CCD图像虽然不利于暗区域的分辨,但可以较好地观测亮区域的层次。最后,根据积分级数的差别对两排CCD的图像数据进行合成来获得大动态范围图像。结果显示,该方案有效地提高了相机的动态范围,当积分级数分别设置为8和48时,动态范围可以提高15.56dB。     

Precise atomic force microscope cantilever spring constant calibration using a reference cantilever array

A method for calibrating the stiffness of atomic force microscope (AFM) cantilevers is demonstrated using an array of uniform microfabricated reference cantilevers. A series of force-displacement curves was obtained using a commercial AFM test cantilever on the reference cantilever array, and the data were analyzed using an implied Euler-Bernoulli model to extract the test cantilever spring constant from linear regression fitting. The method offers a factor of 5 improvement over the precision of the usual reference cantilever calibration method and, when combined with the Systeme International traceability potential of the cantilever array, can provide very accurate spring constant calibrations.     

Accurate determination of spring constant of atomic force microscope cantilevers and comparison with other methods

We present calibration results of commercial AFM cantilevers using the KRISS nanoforce calibrator (NFC) that can determine traceably spring constants with an uncertainty better than 1%, along with the results obtained from other four calibration methods: the dimensional method, the cantilever-on-cantilever method, the Sader method, and the thermal noise method. Two types (contact and tapping mode) of beam-shaped AFM cantilevers with nominal spring constants of 0.9 N m⁻¹ and 42 N m⁻¹, respectively, were investigated in this study. Because of its small uncertainty, the NFC method was used to assess the uncertainties of other four methods through comparisons between values obtained from other methods and those from the NFC method for the same cantilever. Results from other methods were generally in good agreement with those from the NFC method within the uncertainties of other methods claimed in other literatures, but values obtained from the Sader method were differed by up to 40% from the NFC values, which is 2 times worse than the known uncertainty.     

Increasing the versatility of an EMscope SP2000A sputter cryo system on a Hitachi S-570 scanning electron microscope

The EMscope SP2000A Sputter Cryo System provides biologists with a quick and reproducible procedure to freeze, fracture, etch, and sputter coat biological samples, which are then transferred to a cold stage for scanning electron microscopic (SEM) observations. The standard specimen holder, which is supplied with the unit and referred to as a “stub,” will accommodate most specimens; however, fabricating a variety of additional holders to perform more specialized functions considerably increases the versatility of the cryounit and the resolution that can be achieved. For example, the adaptation of small hinged or hingeless gold holders, which are used in the freeze-fracture technique, produces clean fractures, allows for storage of samples in liquid nitrogen and permits samples to be frozen much more rapidly than the large standard holder. A short working distance holder has been designed, which allows samples to be inserted into the final objective lens, thereby resulting in a negative working distance up to ?3 mm. Use of this holder with the upper detector in the Hitachi S-570 SEM, enhances the secondary electron signal and thereby increases resolution of frozen samples severalfold. Another specimen holder has been designed, which allows conventional SEM stubs to be observed without removal of the cryostage. This modification permits use of the EMscope stage and specimen transfer device at room temperature without any further alteration or adjustment. These and other types of modified holders allow investigators to store, manipulate, fracture, and observe biological samples at resolutions not normally attainable with a standard SEM cryostage.     

数码显微镜的设计

介绍了数码显微镜光学系统的设计方法,实现了数码显微镜总体尺寸的缩短,符合数码显微镜小型化的发展方向。采用了多头螺纹调焦机构,改变了传统显微镜由齿轮通过齿条带动镜筒的调焦方式,在调焦过程中具有调焦精细,手感舒适,影象清晰的优点,该结构有利于微型马达的驱动,容易实现数码显微镜调焦的自动化。用精密螺纹连接燕尾槽工作台与调节旋钮,工作台始终在燕尾槽内平稳滑动,克服了数码显微镜在观察移动物体时影像容易晃动的难题。样机研制的结果表明:数码显微镜成象清晰,且结构简单、可靠,光学性能和机械结构均满足设计要求。     

Detection of dichroism with the microscope

Two simple, sensitive, visual methods are described for the detection of dichroism in microscopic objects. 1. The object is oriented at ±45° between crossed polars, and either the polarizer or the analyser is rotated through an equal angle alternately clockwise and anti-clockwise. A dichroic object will brighten as the polar is rotated in one direction and darken as the polar is rotated in the other. If the optic axis of the object lies north-east to south-west and the transmission axes of polarizer and analyser respectively east-west and north-south, a positively dichroic object will darken as the polarizer is rotated anti-clockwise, or the analyser is rotated clockwise. 2. A formally similar method, which avoids the need to rotate either polar, is to orient the object at ± 45° between crossed polars, and insert a Nakamura plate between the polars in an optical plane conjugate with the specimen. Dichroism is indicated by inequality of the apparent brightness of the specimen on either side of the dividing line of the plate. Both methods are more sensitive than visual techniques traditionally used in microscopy. The sign of the dichroism of polished smears of dye particles is discussed. It is suggested that polishing in the dry state orients individual dye molecules, while polishing of a damp smear orients dye molecule aggregates. The relation of dichroism to the colour of stained histological structures, as seen either between crossed polars or with bright-field illumination, is discussed, and the elementary optical theory of dichroism is summarized.