Showing papers on "Resolution (electron density) published in 1977"
TL;DR: Membranes prepared from Torpedo californica electroplax containing acctylcholine receptors have been studied by X-ray diffraction and electron microscopy and Sharp maxima in the scattering pattern indicate that long stretches of secondary structure are present in the receptor-containing membranes.
172 citations
TL;DR: It is shown that with careful design a resolution of about 1/4 msec can be achieved and an example is given of how a high-speed pneumotachograph can be used, with a measure of the pressure across a constriction in the vocal tract, to derive the time variation of the flow conductance and resistance at that constriction.
Abstract: It has been shown previously that a mask-type wire screen pneumotachograph can be constructed with a time resolution of % msec. In this paper it is shown that with careful design a resolution of ab...
114 citations
01 Jan 1977
TL;DR: In this paper, a comparison between synthetic seismograms and well logs illustrates the resolving power of seismic data and the limitations in trying to invert the process and derive logs from seismic data, thus, the seismic log process is called synthetic seismogram construction where the input information is derived from well logs, and modeling where lateral variation is the principal concern.
Abstract: Stratigraphic conclusions from seismic data depend on the data being sufficiently free of noise so that the seismic response is predominantly that of the sediments. Thus good recording and processing are essential. Given a reasonably noise-free response, seismic wavelength limits the detail which can be seen in two dimensions: vertical, or the thickness of stratigraphic units; and horizontal, or the areal size of features. Most reflection events seen on a seismic section are composites of reflections from individual interfaces. Calculating the waveform from a sequence of interfaces helps in understanding and interpreting waveform shape. This process is called synthetic seismogram construction where the input information is derived from well logs, and modeling where lateral variation is the principal concern. A comparison between synthetic seismograms and well logs illustrates the resolving power of seismic data and the limitations in trying to invert the process and derive logs from seismic data--thus, the seismic log process. The ease with which stratigraphic significance can be derived from seismic data also depends on the type of display; those which enhance different aspec s of data are helpful in appreciating geologic significance.
101 citations
TL;DR: A high-resolution scanning electron microscope with a short-focal-length final lens, operating in the "low-loss" mode, is used to make the smallest features in the x-ray replica visible.
Abstract: X-ray micrographs of biological materials have been obtained with a resolution better than 100 angstroms by using x-ray resist as the recording medium. A high-resolution scanning electron microscope with a short-focal-length final lens, operating in the "low-loss" mode, is used to make the smallest features in the x-ray replica visible.
91 citations
88 citations
TL;DR: In this paper, the dependence of depth resolution on sputter depth due to various parameters is theoretically estimated, and the validity of the proposed model is compared with experimental work of different authors.
Abstract: The dependence of depth resolution on sputter depth due to various parameters is theoretically estimated. Comparison with experimental work of different authors shows the validity of the proposed model.
88 citations
TL;DR: A web-like reticulum underlying the human erythrocyte membrane was studied at a resolution of 5-10 nm by means of scanning electron microscope, suggesting that the network has elastic properties.
Abstract: A web-like reticulum underlying the human erythrocyte membrane was studied at a resolution of 5–10 nm by means of a scanning electron microscope. The network was visualized in isolated membranes (ghosts) torn open to reveal their interior space and in residues derived from ghosts extracted with Triton X-100. It formed a continuous (rather than patchy) cover over the entire cytoplasmic surface, except where lifted off or torn away. Filaments (5–40 nm in diameter), annular figures (40–60 nm in diameter), and nodes (30–100 nm in diameter) were prominent in different networks. The dimensions of the filaments and the interstices in the reticulum varied with conditions, suggesting that the network has elastic properties. This reticulum is probably related to the erythrocyte membrane proteins spectrin and actin.
81 citations
65 citations
TL;DR: In this article, the A -type bands, 2 ν 2 + ν 3 and ν 1 + ǫ 2+ǫ 3, with band centers at 3092 and 3638 cm −1, respectively, of 14 N 16 O 2 have been measured with resolution of 0.03 cm − 1 or better.
60 citations
TL;DR: In this paper, a technique for high resolution measurements using a c.w. tunable dye laser was described, with atomic beam fluxes as low as 10 atoms/s, corresponding to a spatial density of about 0.2 atoms/cm 3.
54 citations
TL;DR: X-ray diffraction data sets have been measured from crystals of porcine skeletal muscle glucose 6-phosphate isomerase using a four-circle diffractometer and a Fourier map has been calculated and has been interpreted in terms of the folding of the polypeptide chain.
TL;DR: In this article, a zero-time detector for heavy ions using channel-plates has been designed, and the experimental arrangement was set up in order to measure exactly the timing performances of such a device.
TL;DR: In this paper, the authors used transmission electron microscopy at a resolution of better than 10 A to search for crystalline Si protrusions into, or islands in, the thermally grown SiO2.
Abstract: Thin (200–300 A) cross sections of Si/SiO2 have been examined by transmission electron microscopy at a resolution of better than 10 A to search for crystalline Si protrusions into, or islands in, the thermally grown SiO2. Within the resolution obtained, no evidence was found for any phase separation within the amorphous oxide layer.
TL;DR: Systematic crystallization studies on brewer's yeast aspartic acid transfer RNA have yielded different crystal forms, one of them diffracting to 3 A resolution, and the high resolution crystal form is orthorhombic.
TL;DR: Bands of acetylene in the region 6680-6460 cm −1 recorded with a high resolution infrared spectrograph are assigned to transitions and molecular constants of the levels involved have been evaluated as mentioned in this paper.
18 Jan 1977
TL;DR: In this article, a high resolution electron spectrometer with a computerized multichannel detector system is used for detailed data recordings Several new electronic and vibrational bands are reported.
Abstract: He I induced valence electron spectra are presented from CF3Cl, CF2Cl2 and CFCl3 A high resolution electron spectrometer with a computerized multichannel detector system is used for detailed data recordings Several new electronic and vibrational bands are reported
01 Jan 1977
TL;DR: In this paper, an analysis of optical versus digital computing for image improvement and synthesis in electron microscopy and X-ray crystallography applications is presented, and examples for the improvement of resolution and 3D reconstruction are given.
Abstract: Holographic computing principles make possible image improvement and synthesis in many cases of current scientific and engineering interest. Examples are given for the improvement of resolution in electron microscopy and 3-D reconstruction in electron microscopy and X-ray crystallography, following an analysis of optical versus digital computing in such applications.
TL;DR: In this article, it is shown that it is possible to improve the resolution obtainable in electron micrographs by deliberately using low beam divergence (2 × 10-4 rad) and by minimizing thermal spread in the electron gun.
Abstract: This paper shows that it is possible markedly to improve the resolution obtainable in electron micrographs by deliberately using low beam divergence (2 × 10-4 rad) and by minimizing thermal spread in the electron gun. Point-to-point resolutions in the sub-3 A range will be illustrated for the hollandite structure. Image matching, including the effects of both beam divergence and chromatic aberration, showed that the experimental images could be fitted using 2 A objective aperture, with no divergence and defocus ripple of only 50 A. In fact, these stringent experimental requirements must be met if useful structural information is to be obtained in the 2-3 A range.
TL;DR: In this article, two methods, one based on nonlinear least squares and another based on an approximation, are described for determining the rotational temperature of diatomic molecules from absorption spectra measured with moderate resolution.
Abstract: Two methods, one based on non-linear least squares and one based on an approximation, are described for determining the rotational temperature of diatomic molecules from absorption spectra measured with moderate resolution. Experimental tests with CO and CO/air mixtures gave good results. The importance of line widths and instrumental distortions is emphasized.
TL;DR: In this article, a Fourier map of the cat muscle pyruvate kinase was calculated from X-ray diffraction data collected by screened precession photography to a nominal resolution of 3·1 A.
Journal Article•
TL;DR: In this paper, the influence of backscattered electrons on the edge resolution is estimated for low-Z (Al) and high-Z materials (Au), and the resolution is found to be of the order of 100nm and nearly independent of the atomic number of the sample.
Abstract: A definition of edge resolution is proposed, which is adapted to the pecularities of scanning Auger microscopy. Based on recent monte-Carlo computer simulations for scanning electron microscopy, the influence of backscattered electrons on the edge resolution is estimated for low-Z (Al) and high-Z materials (Au). The resolution is found to be of the order of 100nm and to be nearly independent of the atomic number of the sample.
TL;DR: In this paper, the combination vibration-rotation ν1+ν3 band of SO2 has been recorded under Doppler-limited and atmospheric conditions with 3 × 10−4 cm−1 instrumental resolution using a difference-frequency laser.
TL;DR: Trypsin-cleaved elongation factor EF-Tu-GDP from Escherichia coli crystallizes in several different unit cells in the optimal crystal form, and the tetragonal crystals are well-ordered, stable under X-ray exposure and diffract to at least 2.3 A resolution.
TL;DR: In the field of electron microscopy, it has been shown that the resolution of 2.3 A, close to the interatomic distances in some solids, has been achieved as discussed by the authors.
Abstract: From its beginnings the field of electron microscopy has sought, as its ultimate aim, the ability to study the structure of matter by imaging the individual atoms that compose it. The resolution necessary to attain this goal is obtainable in principle, because the electron wavelengths of the beams normally used are less than 0.1 A, What has kept this goal from realization are practical difficulties in the design and construction of electron microscopes. These difficulties have now been overcome to the extent that resolutions of 2–3 A, close to the interatomic distances in some solids, have been achieved.
TL;DR: In this paper, the v 3 Raman band of CD4 has been recorded with a resolution of about 0.25 cm-1 and the ground-state constants were obtained: B o=2·63264±0.00013 cm −1, D o =2·74±0·15 × 10-5 com −1.
Abstract: The v 3 Raman band of CD4 has been recorded with a resolution of about 0·25 cm-1. This spectrum has been analysed in conjunction with recent high-resolution measurements of the corresponding infra-red band. The following ground-state constants were obtained: B o=2·63264±0·00013 cm-1, D o=2·74±0·15 × 10-5 com-1. The upper-state constants have also been revised in minor respects. The final weighted r.m.s. deviation between experimental and theoretical peak wavenumbers is 0·009 cm-1 for 162 Raman lines.
TL;DR: The energy resolution and response uniformity of HgI2 detectors to nuclear radiation depends strongly on dislocation density and distribution in the Hg2 crystal bulk as discussed by the authors, and several large planar detectors fabricated from the interiors of large single crystals verified this dependence.
Abstract: The energy resolution and response uniformity of HgI2 detectors to nuclear radiation depends strongly on dislocation density and distribution in the HgI2 crystal bulk. Several large planar detectors fabricated from the interiors of large single crystals verified this dependence. Scanning with collimated low-energy (6 keV) and medium-energy (60 keV) gamma-rays confirmed the association of poor resolution and counting efficiency with regions of high dislocation density and crystal imperfection.