bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructural evolution of modified 9Cr-1Mo steel due to annealing and high-temperature fatigue
Authors: Jones Wendell B. , Hills C.R. , Polonis D.H. 
Published: June 2020

The microstructural evolution of Modified 9Cr-lMo steel has been investigated for a variety of conditions, including normalizing, tempering and subsequent annealing. The alleged advantages of the modified alloy for high temperature service, when compared to the standard 9Cr-lMo composition, have been examined for high temperature fatigue conditions; the only difference between the two alloys is the presence of micro additions of V and Nb in the modified alloy.Air cooling (normalizing) of Modified 9Cr-lMo from 1045°C results in the precipitation of fine (FeCr)3C particles within the martensite laths. Additional carbide precipitation and changes in the dislocation structure occur during the tempering of martensite at 700°C and 760°C after normalizing. The precipitation of M23C6 carbides occurs preferentially at lath interfaces and dislocations. The formation of Cr2C was detected during the first hour of tempering over the range 650-760°C, but was replaced by VC within one hour at 760°C. During prolonged annealing at 550°C-650°C, following tempering, the lath morphology remains relatively stable in the absence of simultaneously applied stresses; partitioning of the laths into subgrains and some carbide coarsening are beginning after 400 hr. annealing at 650°C (Fig. 1), but the lath morphology persists. The martensite lath stability is attributed primarily to the VC precipitates distributed along the lath interfaces (Fig. 2) and promotes improved performance of the Modified 9Cr-lMo alloy over the the standard alloy under static tensile and creep conditions.
Dislocation loops in single-crystal NiAl
Authors: Liu Yaping 
Published: June 2020

In the conventional viewpoint, dislocation loops of vacancy type in single crystal NiAl can only exist in Al-rich compositions. Their configurations and their changes when deformation occurs, and their effects on the deformation have not been studied thoroughly.In the present study, nickel-rich NiAl single crystals of 48.1∼48.6 at %A1 were annealed at 1315°C for 50 hours, then cooled at 200°C/hr to permit vacancy condensation. Single-crystal samples cut with an [001] axis then underwent high temperature (850°C) tensile and cyclic deformation. TEM specimens were cut from the undeformed, 0.3% tensile strain, ±0.5 cyclic and 30∼40% tensile deformation samples.Two kinds of dislocations, edge and screw, were found in the undeformed NiAl. Edge dislocations consisted of concentric dislocation loops (Fig. 1) and spiral dislocations (dislocation A in Fig. 2). They lie on cubic planes and have cubic line orientations. Invisibility conditions of g.b=0 and g.b x u=0 show that they have <001> type Burgers vectors normal to the loop planes. The shift in image position on changing the sign of g was used to verify that the loops are vacancy in nature.
Diffraction study on bainite of Cu-Al alloy
Authors: Liu Delu , Ko T. 
Published: June 2020

Structure of bainite in Cu-Al and Cu-Zn-Al alloys has been reported as 3R, 9R or 18R long period stacking structure (LPS) by X-ray and electron diffraction studies. In the present work, a Cu-25.5 (at)% Al alloy sample was heated at 900°C for 2 h then isothermally held at 450°C for 60 s before quenching into iced brine. FIG.1 shows a TEM bright field image of bainite plates (marked B) grown from grain boundary. The parent phase ( with DO3 structure ) has transformed to martensite (marked M ) during cooling from 450° C to 0°C. Both bainite and martensite plates have dense striations inside.Careful diffraction study on a JEOL 2000FX TEM with accelerating voltage 200 KV revealed (FIG.2) that the diffraction patterns contai_ning the same zone axis [001] ( hexagonal index ) or [111]c ( cubic index ) are from a bainite plate with obtuse V-shape. They are indexed as [010], [140], [130], [120], [230], [340] and [110] zone pattern for hexagonal system respectively.
A new alloy phase produced in the co-deposited Bi-Mn films in a composition range 50-30 at% Mn
Authors: Yamada Takashi , Yoshida Kentaroh 
Published: June 2020

Only one alloy phase, MnBi, is described to exist in the equilibrium phase diagram of Bi-Mn system. However, other alloy phase than MnBi were successfully prepared by the present authors by making use of vacuum deposition techniques. One of them is a metastable Mn3Bi, which forms in co-deposited films whose composition are in a range, 85 to 65 at% Mn. The authors are now investigating the films in a neighboring composition range, 50 to 30 at% Mn.The films in the as-deposited state, which are prepared by the co-deposition and has a composition in this range, show halos and Debye-Sherrer rings in diffraction patterns. The rings can be indexed as those of Bi type lattice even though as much as 50 to 30 at% Mn must be included in the film. No crystal grains of Mn nor of any other alloy phases were detected in the micrograph. When the films was warmed up ty irradiating with an intense electron beam in an microscope, new crystals were observed to appear and grow. Figure 1 is a bright-field image showing this change in the film of 37.9 at% Mn. The intense beam was focused at the central part of the figure and black areas at this place are the crystals produced by this heating. Small grains surrounded by the black areas are the Bi type crystals which are going to suffer from the change. Other part of the figure than this central region, including these small grains, still show diffuse halos and the Bi type Debye-Sherrer rings. Black areas eating these unreacted regions are single crystalline for the most cases. Two of diffraction patterns taken from these black areas are shown in Figs. 2 and 3.
Interface state and bonding effect of clay mineral-organic polymer composite material
Authors: Chenghuang Xu , Kaiyi Chen 
Published: June 2020

The urgent need of new types of materials accelerates the research and development of polymeric composite material, among them the ones composed of organic polymer and inorganic polymeric particles are very spectacular.Clay mineral particles are inorganic nonmetallic particles of layered structure. As a rich and cheap resource, clay mineral has found wide applications in polymeric composite material industry, but its frequent use is no more than a filler. For heighten its use value, it is imperative to make full use of its structural property by trying various pretreatments. To this end, kaolin , the strengthening agent of rubber, is chosen as the object and SEM-EDS analysis are chosen as the means of our study. Our study centers on: a) the influence of activation and modification on the structure and surface state of kaolin particles; b) the interface state of modified kaolin and rubber and their bonding effect.
Observations on a fibrous form of silicon carbide
Authors: Otero Diaz L.C. , Landa Canovas A.R. , Hansen S. , Hyde B.G. 
Published: June 2020

During a phase and structure analysis of the ytterbium sulphide system we observed, in addition to various ytterbium sulphides , some fibrous crystals ≃10-100 μm long, ≃0.5 μm diameter, e.g. Fig.10. In the optical microscope they were seen to be crystalline, white and transparent. In the electron microscope planar defects were seen in parts of them; usually normal to the fibre axis, and often closely aggregated into groups, e.g. Figs. 1a and 2a, which were taken with JE0L 2000 FX and 4000 EX microscopes.The fibre morphology was unexpected, and ytterbium sulphides (with the exception of Yb2S3, which is yellow)are black and metallic in appearance. Futhermore the electron diffraction patterns from the fibres did not correspond to any knownor possible YbS phase/ structure.EDSxanalysis (with a LINK AN 10000, JE0L 2000 FX microscope) revealed the presence of Si in the fibres, but not heavier elements.
Microstructural characterization of Ca2SiO4 particles in a CaZrO3 and a MgO matrix
Authors: Kim Y. J. , Mast E. , Hou T. I. , Kriven W. M. 
Published: June 2020

Dicalcium silicate (abbreviated C2S) has five polymorphs at atmospheric pressure. The monoclinic (β) to orthorhombic (γ) transformation is accompanied by a 12 % volume increase on cooling and a 4.6° unit cell shape change. These analogies to ZrO2 make C2S a potential transformation toughener. Recently C2S particles have been successfully mixed with a calcium zirconate (abbreviated CZ) phase to form a composite ceramic with a microstructure similar to ZTA.The two composites were prepared in different ways. For the C2S/CZ composite, C2S powder was prepared by the Pechini method with starting materials of Ca(NO3)2 and colloidal silica. 10 vol % C2S was mixed with CZ and sintered at 1600°C for 2 hours. For the C2S/MgO composite, C2S powder was formed by reaction of SiO2.xH2O and CaCO3 at 1450°C. Solutions containing 15 vol % C2S were mixed with solutions of fine magnesia containing an acrylic resin. The suspension was dried and sintered at 1600°C for 3.5 hours. Microstructures of both composites were examined by SEM and TEM.
Microstructural study of the effects of potassium vapour on carbonised materials
Authors: Garrick L.S. , Fryer J.R. , Baird T. 
Published: June 2020

Metallurgical coke in the blast furnace provides a permeable matrix through which reducing gases may ascend and molten materials descend. A lack of permeability will inevitably lead to a poor gas distribution and result in a reduction of the furnace output and efficiency.A decrease in the permeability of the carbonaceous coke matrix arises when changes induced by the blast furnace environment occur in the properties of the material and effect the matrix voidage by causing a reduction of coke strength. A major influence of change within the blast furnace is the presence of recirculating alkali, particularly potassium, which is known to induce considerable microstructural changes (enhanced localised ordering), within the metallurgical coke. These microstructural changes lead to structural weakening as a consequence of a variety of factors:-
Observation of the Sulphur Atoms in Cu2S Using HREM
Authors: Yu Y.D. , Guan R. , Kuo K.H. , Hashimoto H. 
Published: June 2020

We have indicated that the lighter atoms such as oxygen in Cu2O can be observed at the specimen with optimal thicknesses based on the dynamic effect of electron diffraction(1). This rule in principle should hold good for the imaging of other lighter atoms such as sulphur atom in Cu2S. However, this point of view needs further experimentally confirm because up to now only oxygen atoms have been observed in Cu2O and a series of new suboxides of copper and nickel (2). In addition, the sulphur atom is much heavier than oxygen one though is still lighter than copper atom. In the present report we provide such a confirmation.The crystallites of Cu2S shown in Fig.l were obtained by sulfurizing at 300°C of the copper thin film which was sealed in a glass tube with mg sulphur left on the tube wall in a vacuum of about 10-2 Pa. The energy dispersive spectrocscopy analysis indicated that they are the sulfides and the electron diffraction analysis indicated they have anti-fluorite structure.
New form of Transmission Cross Coefficient for High-Resolution Imaging
Authors: Ishizuka Kazuo 
Published: June 2020

It is well known that taking into account spacial and temporal coherency of illumination as well as the wave aberration is important to interpret an image of a high-resolution electron microscope (HREM). This occues, because coherency of incident electrons restricts transmission of image information. Due to its large spherical and chromatic aberrations, the electron microscope requires higher coherency than the optical microscope. On an application of HREM for a strong scattering object, we have to estimate the contribution of the interference between the diffracted waves on an image formation. The contribution of each pair of diffracted waves may be properly represented by the transmission cross coefficients (TCC) between these waves. In this report, we will show an improved form of the TCC including second order derivatives, and compare it with the first order TCC.In the electron microscope the specimen is illuminated by quasi monochromatic electrons having a small range of illumination directions. Thus, the image intensity for each energy and each incident direction should be summed to give an intensity to be observed. However, this is a time consuming process, if the ranges of incident energy and/or illumination direction are large. To avoid this difficulty, we can use the TCC by assuming that a transmission function of the specimen does not depend on the incident beam direction. This is not always true, because dynamical scattering is important owing to strong interactions of electrons with the specimen. However, in the case of HREM, both the specimen thickness and the illumination angle should be small. Therefore we may neglect the dependency of the transmission function on the incident beam direction.
Structure of PhoE Porin as Determined by Electron Crystallography
Authors: Jap Bing K. 
Published: June 2020

PhoE porin is a member of a family of pore forming proteins that are found in the outer membrane o Gram-negative bacteria. In E. coli , there are a variety of porins, such as OmpF, OmpC and PhoE. These porins have been shown to have no specific binding site for substrate although PhoE porin has been demonstrated to have some selectivity for anions and phosphate-containing compounds. Porins font general diffusion channels allowing small molecules, such as nutrients and waste products, of less that about 600 daltons, to diffuse freely across the membrane. In addition, porins also act as receptors for various bacterial phages. The closing and opening of the porin channels have been shown, at least, in vitro , to be voltage-gated.We have purified PhoE porin and reconstituted the purified protein with lipid, forming two-dimensional crystalline patches. The crystalline patches diffract to resolution better than 3.0Å. We have collected diffraction patterns of PhoE porin embedded in trehalose at various tilt angles up to about 60 degrees. The diffraction patterns were combined to form a complete 3-D diffraction data set. The diffraction data show that there are two orientations of B-strands, one with the strand axis normal to the membrane plane and the other with the axis tilted about 35 degrees from the membrane normal. This is consistent with projectior map of PhoE porin at 3.5Å resolution which shows that a significant fraction of the 6-sheet strands an oriented with the strand axis almost normal to the membrane plane.
Cryo-Electron Microscopy and Correlation Averaging of Frozen-Hydrated, Polymorphic 2D Crystals of the Mitochondrial Outer Membrane Channel
Authors: Guo Xiao-Wei 
Published: June 2020

Voltage-dependent, anion-selective channels (VDAC) are formed in the mitochondrial outer membrane (mitOM) by a 30-kDa polypeptide. These channels form ordered 2D arrays when mitOMs from Neurospora crassa are treated with soluble phospholipase A2. We obtain low-dose electron microscopic images of unstained specimens of VDAC crystals preserved in vitreous ice, using a Philips EM420 equipped with a Gatan cryo-transfer stage. We then use correlation analysis to compute average projections of the channel crystals. The procedure involves Fourier-filtration of a region within a crystal field to obtain a preliminary average that is subsequently cross-correlated with the entire crystal. Subregions are windowed from the crystal image at coordinates of peaks in the cross-correlation function (CCF, see Figures 1 and 2) and summed to form averages (Figure 3).The VDAC channel forms several different types of crystalline arrays in mitOMs. The polymorph first observed during phospholipase treatment is a parallelogram array (a=13 run, b=11.5 run, θ==109°) containing 6 water-filled pores per unit cell. Figure 1 shows the CCF of a sub-field of such an “oblique” array used to compute the correlation average of Figure 3A. With increased phospholipase treatment, other polymorphs are observed, often co-existing within the same crystal. For example, two distinct (but closely related) types of lattices occur in the field corresponding to the CCF of Figure 2: a “contracted” version of the parallelogram lattice (a=13 run, b=10 run, θ=99°), and a near-rectangular lattice (a=8.5 run, b=5 nm). The pattern of maxima in this CCF suggests that a third, near-hexagonal lattice (a=4.5 nm) may also be present. The correlation averages of Figures 3B-D were computed from polycrystalline fields, using peak coordinates in regions of CCFs corresponding to each of the three lattice types.
Three-Dimensional Structure of Cobalt-Tetrammine-ATP Induced Membrane Crystals of Na,K-ATPase
Authors: Skriver Elisabeth , Hebert Hans , Kavéus Urban , Maunsbach Arvid B. 
Published: June 2020

2-D membrane crystals of renal Na,K-ATPase have been induced to obtain structural information about the sodium pump. Crystalline arrays of the p21 and the p1 type formed during incubation in media containing vanadate and magnesium have been analyzed by image processing and the 3-D structures determined. We report here a new 3-D structure reconstructed from membrane crystal with p4 symmetry that were formed during incubation with cobalt-tetrammine-ATP (Co(NH3)4ATP) which is an MgATP analogue complex that binds to the enzyme and stabilizes it in an E2conformational state.Membrane-bound Na,K-ATPase purified from renal outer medulla was incubated in 0.5 mM Co(NH3)4ATP and 0.5 mM CoCl2for one hour at 37°C and then at 4°C for 28 days. Tilt series of crystalline membrane fragment negatively stained with 1% uranyl acetate were recorded in a Jeol 100CX electron microscope at angels from −60° to +60° with increments of 6°. Electron micrographs of the tilt series were digitized into 512 × 512 pixel squares using a EIKONIX 1412 scanner and image processing performed with the "EM" program system.
Design of the VG HB603 300kV Field-Emission STEM
Authors: von Harrach H.S. , Colling J.A. , Keyse R. , Morphew J. 
Published: June 2020

A new generation of UHV field-emission STEMs operating at up to 300 kV has been designed by VG Microscopes. The design philosophy of these instruments has been to improve further the analytical performance achieved by 100 kV cold field-emission STEMs, such as the VG HB501 series.There are three types of instrument with a common basic design:HB603: an analytical STEM with optimised X-ray microanalysis (0.3srad collection angle per detector) and parallel/serial electron energy-loss facilities;HB603U: a high-resolution STEM with optimised high-angle dark-field detection and < 0.13 nm resolution;HB603S: a full UHV STEM with Auger analyser and specimen preparation facilities at 3 × 10-10 mbar pressure throughout the instrument.
A New Illumination System for an Analytical Transmission Electron Microscope Using a Condensor Objective Lens
Authors: Benner Gerd , Bihr Johannes , Prinz Manfred 
Published: June 2020

The most suitable objective lens for an analytical transmission electron microscope (TEM) is the single-field condensor objective lens developed by Riecke/Ruska [1]. This lens permits both high-resolution TEM operation and the generation of small electron probes needed for the analytical, microditfraction and scanning transmission electron microscope (STEM) modes. The symmetrical position of the specimen allows maximum specimen tilting and an optimum detector arrangement (EDX, SE, BSE). For this type of lens in TEM illumination mode an auxiliary lens has to be used or the excitation of the objective lens must be changed. This paper describes an automated illumination system which realizes the Koehler illumination [2] and does not require an auxiliary lens.An illumination system for use in an analytical TEM must meet the following requirements:
Computer-Assisted Microscope Alignment
Authors: Marks L.D. 
Published: June 2020

Full alignment of a high resolution electron microscope, including alignment of the beam tilt, is a very difficult process. Whereas astigmatism correction is relatively straightforward, correcting the beam tilt is by no means so simple and there is a strong interaction between astigmatism and tilt so that it is possible to apparently correct the two at one defocus. To overcome this problem, the method of applying a ± tilt oscillation to the beam has been introduced previously, the principle being to adjust the texture of an amorphous carbon film image so that it is symmetric with respect to the tilt oscillations. This procedure works, but in practice is not easy to use and there are additional experimental problems in terms of loss of intensity due to insufficiently corrected beam shift/tilt purity.As an extension of this process, and as a general extension of astigmatism correction as well, we have developed a procedure for providing a computer generated optical diffraction pattern to compliment the standard TV image. One critical problem was providing optical diffraction patterns at a sufficiently rapid speed to make the process experimentally viable; one optical diffraction pattern every 5 seconds for example is too slow. The numerical procedure can be broken down into a number of different steps:
Yag Single Crystals for Scintillators of Stem
Authors: Hibino M. , Irie K. , Autrata R. , schauer P. 
Published: June 2020

Although powdered phosphor screens are usually used for scintillators of STEM, it has been found that the phosphor screen of appropriate thickness should be used depending on the accelerating voltage, in order to keep high detective quantum efficiency. 1 It has been also found that the variation in sensitivity, due to granularity of phosphor screens, makes the measurement of fine electron probe difficult and that the sensitivity reduces with electron irradiation specially at high voltages.In order to find out a preferable scintillator for STEM, single crystals of YAG (yttrium aluminum garnet), which are used for detecting secondary and backscattered electrons in SEM were investigated and compared with powdered phosphor screens, at the accelerating voltages of 100kV and 1 MV. A conventional electron detection system, consisting of scintillator, light guide and PMT (Hamamatsu Photonics R268) was used for measurements. Scintillators used are YAG single crystals of 1.0 to 3.2mm thicknesses (with surfaces matted for good interface to the light guide) and of 0.8mm thickness (with polished surface), and powdered P-46 phosphor screens of 0.07mm and 1.0mm thicknesses for 100kV and 1MV, respectively. Surfaces on electron-incidence side of all scintillators are coated with reflecting layers.
S/N Ratio Characteristics of the Imaging Plate System for A TEM
Authors: Oikawa T. , Mori N. , Osuna T. , Ohnishi M. , Kawasaki M. 
Published: June 2020

The fundamental characteristics of the Imaging Plate System for a TEM (TEM-IP System) have already been ascertained and the system has began to be put to practical use in various fields of transmission electron microscopy. When considering the practicability of any image recording device, the “image quality” is an important factor.In this study, the S/N ratio of the TEM-IP System, one of the evaluation factors for the “image quality” of the system is estimated.Signal measurement was carried out under two readout conditions high resolution mode (HR-Mode) and high sensitivity mode (HS-Mode), which are available in the IP-reader of the PIXsysTEM. In order to distinguish between instrumental noise (system noise) and noninstrumental noise (quantum noise), the S/N ratio was measured as a function of the electron dose, and the dose was widely varied in the dynamic range of the system.