摘要:

SUMMARYThis paper describes and discusses for microscopists and spectroscopists the choice of computer equipment and the design of programs used in the Denver Universal Microspectroradiometer (DUM). This instrument is an accurate computerized photon‐counting microspectrophotometer, microspectrofluorimeter and microrefractometer. The computer is used to control the operation of the system, to acquire radiometric data of various kinds, and to reduce, analyse and output the data in a readily usable form.Since the radiometer was designed to carry out many kinds of measurements in a variety of micro‐ and macroscopic specimens, and since different methods of microscopy or spectroscopy have to be combined in various ways for the study of any one specimen, no single master‐program could fulfil efficiently all foreseeable requirements. Therefore, the programming developed is interactive, modular, hierarchical and hybrid. Modular interactive programming makes it possible for almost any kind of main program, applicable to almost any kind of measurement, to be assembled quickly from a collection of hierarchical subroutines. Main programs are short and composed mainly of Fortran statements calling subroutines; subroutines, in turn, automatically call other subroutines over many levels. The subroutines are independently written and optimized for maximum operational efficiency in the computer system used, or for maximum ease of transfer to other systems.This approach to programming enables someone unfamiliar with computer languages to operate the radiometric system from the console of the CRT terminal. The writing of new main programs, by linking groups of existing subroutines, requires only a minimum acquaintance with Fortran; only the writing and revision of subroutines requires programming experience.Differences and similarities in the method of computer operation between the present system and other computerized radiometers are briefly disc

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04057.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYA simple accessory has been designed which can be used for all types of metal or carbon evaporation in either an upwards or downwards direction as required. A method of preparing platinum carbon rod sources which makes possible successive repeatable evaporations of platinum carbon is also described.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04058.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYAs measured by the life‐time of their electron diffraction patterns, the radiation sensitivity of anthracene and coronene at 500 kV is reduced by a factor of three to four at liquid helium temperature in comparison to room temperature. Forl‐valine the ratio is about 1·8 but there is a wide variation in the results, possibly due to differences in crystal thickness. The end‐dose at 20°K for valine is equivalent to 13 electrons/Å2; for anthracene and coronene it is about 600 electrons/Å2at room temperature. The variation of end‐dose with temperature shows that at least two mechanisms must be involved in damage to such compounds, possibly concerning the breaking of intermolecular and intramolecular bonds, r

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04059.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYStandard specimens were examined in a transmission electron microscope with a top entry stage. Using a range of objective focal lengths, measurements of contrast, resolution and magnification range were made. Focal lengths up to 14 mm were examined. The contrast was found to increase with increasing focal length, being twelve and a half times greater at 14 mm focal length than at the normal high resolution mode of 2 mm focal length. Resolution, determined by the fresnel fringe method decreased from 0·3 nm to 3·5 nm. The photographic image magnification was reduced from × 1000– × 500,000 at 2 mm focal length to ×100‐× 50,000 at 14 mm foc

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04060.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYCalcium stearate monomolecular films were examined by electron microscopy using replica techniques. The effects of two evaporants, palladium and platinum, on the structure of Langmuir‐Blodgett monolayers and multilayers were investigated. The fine structure appears to be altered unless precautions are taken to minimize the radiation heat transfer during the shadow‐casting procedure. The structural features of deposited monolayers are also influenced by the underlying solid substr

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04061.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYTwo‐dimensional Monte Carlo computations have been used to predict the backscattered and secondary electron intensity profiles when a plane surface has a square of sidedstanding out from it. This was taken as a model for a gold cube of dimensionsdsituated on a thick gold substrate. This latter situation has been approximately reproduced experimentally and the predicted intensity profiles show quite good agreement with the observed intensity profiles for a range of values of the dimension

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04062.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYCathodoluminescence observations on biological compounds are compared with previously established data from ultra violet and visible light excitation studies. The comparison demonstrates that the same molecules are responsible for the luminescence properties of macromolecules independent of the type of exciting radiation. Natural cathodoluminescence was also observed from cells. Moreover, advantages gained by the absorption of strongly cathodoluminiscent dyes into cells are demonstrated.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04063.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYIt is shown that by making a map of channelling patterns on the surface of a sphere, the long range distortions inevitably present in planar maps can be avoided. The construction and use of the map is described.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04064.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYA comparison of currently used methods of tissue fixation for scanning electron microscopic study of vascular endothelium revealed thatin situfixation by intravascular perfusion is superior to immersion for the preservation of endothelial surface morphology.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04065.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYA rapid method of extracting nuclei in high yield from small quantities of plant material, for freeze‐fracture studies is described. The nuclei are gently isolated directly into buffered glutaraldehyde which ensures good preservation of ultrastructure. Removal of the cell wall allows rapid glycerination of the specimen and faster cleaning of the replic

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04066.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY