bluuebunny/crossref_metadata_2025_split huggingface dataset:
Searching for the causes why some of the paintings by Mihaly Munkacsy are darkening
Authors: Pozsgai Imre , Erdöhalmi-Torok Klara 
Published: June 2020

The paintings by the great Hungarian master Mihaly Munkacsy (1844-1900) made in an 8-9 years period of his activity are deteriorating. The most conspicuous sign of the deterioration is an intensive darkening. We have made an attempt by electron beam microanalysis to clarify the causes of the darkening. The importance of a study like this is increased by the fact that a similar darkening can be observed on the paintings by Munkacsy’s contemporaries e.g Courbet and Makart. A thick brown mass the so called bitumen used by Munkacsy for grounding and also as a paint is believed by the art historians to cause the darkening.For this study, paint specimens were taken from the following paintings: “Studio”, “Farewell” and the “Portrait of the Master’s Wife”, all of them are the property of the Hungarian National Gallery. The paint samples were embedded in a polyester resin “Poly-Pol PS-230” and after grinding and polishing their cross section was used for x-ray mapping.
Valence state analysis of elements by EPMA and its application
Authors: Liqing Chen , Zuqin Liu , Wei Zhang 
Published: June 2020

Valence state analyses of Fe and Mn in oxides by EPMA have been reported in literature. In this paper, the effects of valence state on intensity ratios ILα/IKα and ILα/ILβ of Cu, Ni, Co, Fe, Mn, Cr and their oxides, and on intensity ratios ILβ2/ILα1 and ILγ1/ILα1 of Mo, Nb, Zr and their oxides were studied. It was observed that intensity ratios change with valence states in accordance with some regularities, and these effects could be utilized for analyzing the valence states of catalysts.Valence state analysis of elements by EPMA is based on the fact that changes in the states of valence electrons in the outer shells of an atom cause corresponding changes in line intensities. The M electrons of Cu, Ni, Co, Fe, Mn, Cr and the N electrons of Mo, Nb, Zr are valence electrons. Line Kα1,2 and six lines of L are produced from the transitions of K-L2,3 and L-M or L-N respectively.
Quantitative E. D. Analysis At High Count-Rates
Authors: Reed S.J.B. 
Published: June 2020

Hitherto quantitative E.D. analysis has been carried out generally at pulse throughput rates up to about 5 kHz. Some commercially available E.D. systems are, however, now capable of rates exceeding 30 kHz. The present study is concerned with the feasibility of quantitative analysis at high count-rates, with the emphasis on applications to geological samples, especially silicates. Benefits of high count-rates include reduction in the time required per quantitative analysis. Also lower detection limits are obtainable with a constant time. Furthermore, flexibility with regard to count-rate is useful in combined E.D. and W.D. analysis.The Link Analytical XP2 pulse processor used in this study has a choice of 6 ‘process times’ (equivalent to the peaking time in a conventional amplifier). The throughput (or output) rate as a function of input count-rate for process times 1-4 is shown in Figure 1. The shortest (no. 1) gives a maximum throughput rate of 32 kHz, the dead time per pulse being 12 μS.
The Characterization Of Organic Charge Transfer Superconductors By Microreflectance Spectroscopy
Authors: Hill S. L. , Krishnan K. , Ferraro J. R. 
Published: June 2020

Certain classes of organic charge-transfer salts demonstrate superconducting behavior at liquid helium temperatures. Single crystal x-ray diffraction and infrared microreflectance analysis have been performed on several conducting systems to associate the nature of the crystalline structure with the electrical conductivity. The infrared spectrum for a single crystal salt exhibits absorptions which correlate with superconducting behavior.DiscussionWilliams and coworkers have performed x-ray Crystallography experiments to demonstrate the presence of an anion cavity between radical cation stacks- of bis(ethylenedithio)- tetrathiafulvalene (ET). The sulfur…sulfur interstack distance in a beta or kappa phase salt assumes a value less than the Vanderwaals distance and exhibit a superconducting (two dimensional) metal behavior (verified by Fermi surface calculations) at 1-20K. The structures of alpha and beta phase ET2I3suggest the potential for several potential intermolecular interaction modes. It may be observed that the beta phase permits both interstack as well as H … X anionic interactions, whereas these interactions are less likely to occur in the alpha phase.
Complementary Molecular Information on Phthalocyanine Compounds Derived From Laser Microprobe Mass Spectrometry and Micro-Raman Spectroscopy
Authors: Fletcher Robert A. , Etz Edgar S. 
Published: June 2020

Various metal phthalocyanines (Pc's) have come under study because of their optoelectric properties which make them attractive materials for fabrication of ultra-fast molecular electronic devices. Probably the most extensively investigated metal Pc is vanadyl phthalocyanine, VOPc, which has been proposed as a medium for optical storage devices and has been shown to be a photoconductor in the infrared. Several methods have been used to elucidate the relationship between molecular structure and the Pc's optical and electronic properties.The thrust of this work is to show how well laser microprobe mass spectrometry (LAMMS) and micro-Raman spectroscopy complement each other to provide information so that structural assignments can be made. The vibrational frequencies obtained from micro-Raman spectroscopy indicate molecular structure while mass spectrometry provides the mass (m/z) of the molecule along with certain features of the structure through the fragmentation process. The compounds studied are the metal-free Pc (H2PC), and the derivatives containing the divalent cations of Ni, Cu, and VO. Some of the results are illustrated here for VOPc.
Imaging of Al-Li-Cu alloys with a Scanning Ion Microprobe
Authors: Soni K.K. , Williams D.B. , Chabala J.M. , Levi-Setti R. , Newbury D.E. 
Published: June 2020

In contrast to the inability of x-ray microanalysis to detect Li, secondary ion mass spectrometry (SIMS) generates a very strong Li+ signal. The latter’s potential was recently exploited by Williams et al. in the study of binary Al-Li alloys. The present study of Al-Li-Cu was done using the high resolution scanning ion microprobe (SIM) at the University of Chicago (UC). The UC SIM employs a 40 keV, ∼70 nm diameter Ga+ probe extracted from a liquid Ga source, which is scanned over areas smaller than 160×160 μm2 using a 512×512 raster. During this experiment, the sample was held at 2 × 10-8 torr.In the Al-Li-Cu system, two phases of major importance are T1 and T2, with nominal compositions of Al2LiCu and Al6Li3Cu respectively. In commercial alloys, T1 develops a plate-like structure with a thickness <∼2 nm and is therefore inaccessible to conventional microanalytical techniques. T2 is the equilibrium phase with apparent icosahedral symmetry and its presence is undesirable in industrial alloys.
Design for an Ultraclean, Computer-Controlled Freeze Dryer For Biological Specimens
Authors: Flenniken Robert , Kopf David , LeFurgey Ann , Ingram Peter 
Published: June 2020

Electron probe x-ray microanalysis (EPXMA) requires accurate and consistent preparation of samples in order to obtain meaningful quantitative data. For biological systems it is critical that the morphological state and elemental content of individual subcellular compartments are preserved, particularly in the case of cryofixed tissue in which the cryosectioned sample is dehydrated prior to microanalysis.In dehydrating samples several difficulties are encountered: (1) contamination from the vacuum system used in the process, (2) exposure to warm, humid room air during transfers between instruments, and (3) lack of control over temperature changes of the specimen stage and, therefore, the specimen. While it is possible to circumvent these problems by performing the dehydration in the column of the microscope, it is an inefficient use of the microscope when one freeze drying cycle may exceed 24 hours.A design for a freeze drying instrument has been developed which reduces the above negative effects and frees the microscope for EPXMA.
Loss of Elements From Anhydrously Fixed Pollen During Thin Sectioning
Authors: Skilnyk Hilary R. , Lott John N.A. 
Published: June 2020

Anhydrous fixations are not commonly considered as a means of preparing biological specimens for energy-dispersive x-ray analysis (EDX). Cucurbita maxima and Cucurbita andreana pollen grains were fixed anhydrously because water-soluble materials such as potassium phytate are extracted by aqueous fixatives. Combining anhydrous fixation with anhydrous sectioning techniques demonstrated significant reduction in the extraction of K, Mg and P from globoid particles in the tube cell cytoplasm in pollen.Air-dried Cucurbita maxima and Cucurbita andreana pollen grains were fixed for 4h in 2% paraformaldehyde dissolved in pure glycerol (W/V). Samples were washed for 1.5 h in (1:1) glycerol: 100% ethanol mixture. Dehydration began at 95% ethanol because glycerol is hygroscopic and not completely anhydrous. Infiltration was carried out beginning with propylene oxide followed by a series of Spurr’s resin: propylene oxide mixtures which consisted of 1:3, 1:2, 1:1, 2:1, and 3:1 proportions that were followed by three changes of 100% resin.
X-Ray Microanalysis of the Intestine: Identification of Electrolyte Secreting Cells
Authors: von Zglinicki Thomas , Roomans Godfried M. 
Published: June 2020

Frozen dried cryosections of mouse jejunum were investigated. Besides Paneth and Goblet cells, two different types of crypt enterocytes could be distinguished according to clearly different electrolyte concentrations and to the presence (type A) or absence (type B) of small secretion granula in the cytoplasm.Secretion was stimulated by an intraperitoneal injection of either isoproterenol or pilocarpine. In some experiments, isoproterenol stimulation was blocked by alloxan, a potent inhibitor of the adenylate cyclase. Changes of cytoplasmic element concentrations were measured in frozen dried cryosections. In addition, the water content of the cells was measured by fully quantitative bulk specimen x-ray microanalysis.It was expected that actively secreting cells should display a decrease of Cl concentrations. This behaviour was confirmed in crypt A cells exclusively (Fig. 1). Therefore, it was concluded that crypt A cells are the main secretory cells in the intestinal epithelium.The water content of all epithelial cells in the intestine was found to increase under pilocarpine stimulation and to decrease under isoproterenol stimulation (Fig. 2).
Use of X-Ray Microanalysis to Characterize Liver Necrosis of Mice, Rats, And Guinea-Pig
Authors: Augsten Kurt , Güttner Jürgen 
Published: June 2020

On the basis of ultrastructural findings several types of cell death have been distinguished, which characterize different pathological mechanisms of death. Necrosis refers to the progressive degradation of cell structure after death caused by different toxins. Apoptosis is characterized morphologically by shrinking and budding of a cell and by the appearance of discrete apoptic bodies which varied considerably in size. The aim of this work was by means of x-ray microanalysis to characterize different liver necrosis of well-known and unknown aetiology.Liver necrosis of mice that had been suffered from Tyzzer’s disease, mouse hepatitis virus infection and infectious ectromelia as well as necrosis of unknown origin of guinea-pigs were investigated. Rats receiving CCl4 (p. o.) were used as reference. The liver was processed for routine histology by fixation in 4 % neutralized formalin for two days and embedded in paraffin; subsequently following serial sections, 4-5 um thick, were mounted on glass slides and Al-foil or C-discs.
Low-Energy Electron Induced X-Ray Spectroscopy (LEEIXS), An Emerging Technique in Surface and Thin-Film Analysis. New Developments and Applications
Authors: Charbonnier M. , Romand M. , Gaillard F. 
Published: June 2020

Within the last two decades analysis and characterization of surfaces, interfaces and very thin films have become of considerable importance in many fields of modern technology. This increasing demand has lead to a rapid development of various surface and near-surface analytical techniques. Some of these methods such as XPS, AES, SIMS and ISS have matured both with respect to instrumentation and methodology and therefore are now sufficiently well-established. Others are yet in their infancy but possess a large potential and this is the case of low-energy electron induced x-ray spectrometry (LEEIXS) discussed hereafter.The instrument is a wavelength-dispersive x-ray spectrometer in which the conventional x-ray tube has been replaced by an electronically stabilized gas-discharge source. Such a system operates as an electron source under the primary vacuum of the spectrometer (≃ 10−1 torr). Typical operating conditions are in the range 0.5-5 kV with a current of 0.1-0.5 mA and the diameter of the electron beam at the sample surface is less than 1 cm2.
A Study on the Occurrence of Gold in Unoxidized Carlin-Type Ores in China Using AEM, SEM-EDX and SXRF
Authors: Yongkang Liu , Shirong Liu , Guangquan Wan , Lindi Zhou , Jilian Li , Fangqiong Lu 
Published: June 2020

The knowledge about the occurrence of gold is essential both to the explanation for the genesis of gold mineralization in its deposits and to the evaluation and exploration or even smelt process of its ores. It has been well known that the gold occurrence in the Carlin-type ores still remains a difficult question to be answered because of the tiny scale of its locality and its very low content.This paper reports the results of our analysis on some gold bearing minerals in the Carlin-type ores discovered during recent years in China with combined use of analytical electron microscopy (AEM), scanning electron microscopy-energy dispersive X ray spectrometry (SEM-EDX) and synchrotron X ray flourescence analysis (SXRF) techniques as following:(1) Some gold occurred as submicron size grains in the ores (see Photo 1-4 and Figure 1-3) with grain size generally less than 0.2 micron.(2) It has been found by AEM and SEM-EDX observation and SXRF analysis that gold occurred as micrograins embedded in the boundaries of clay or quartz minerals rather than, as said, entered the lattice or adhered as a covering film to the surface of clay minerals (see Figure 4).
Quantitative Microanalysis of ZrO2/Non-Oxide Ceramic Composites
Authors: Miller P.R. , Hannink R.H.J. , Muddle B.C. 
Published: June 2020

Addition of zirconia (ZrO2) to oxide and non-ox1de ceramics improves consolidation behaviour, strength and toughness of fabricated bodies. Such materials are generally referred to as zirconia-toughened ceramics, ZTC. Typical examples of such systems include oxide matrices such as α- and β"-Al2O3, MgO.Al2O3 (spinel), ZrSiO4 (zircon) and ZnO; non-oxide systems include Sic, Si3N4, TiN, TiCN and TiB2. In these materials an Improved toughness is anticipated as a result of the stress-activated tetragonal to monoclinic transformation in the dispersed ZrO2. In an effort to understand the consolidation mechanisms and microstructural features leading to the improved strength and toughness of ZrO2-TiX (X=C,N,B2) based composites, a systematic study has been made of the composition of the component phases using energy dispersive x-ray spectroscopy (EDXS) and electron energy loss spectroscopy (EELS).The experiments were conducted on two types of samples. Firstly, to establish the kTizr factors for EDXS analysis and to assess the detectability limits of the EELS technique, a series of TiO2-ZrO2 solid-solution standards containing 2.5-13 mole% TiO2 were prepared.
Chemical Analysis of Layered Structures by Digital X-ray and EELS Mapping on an HB501 STEM
Authors: Long N.J. , Petford-Long A.K. 
Published: June 2020

The development of materials formed from multilayer structures (MLS), with compositional modulation on the nanometre scale, such as semiconductor multiple quantum-well structures (MQW), used as lasers in fibre-optic communications, and metallic MLS such as Co/Cr and Co/W, for use as perpendicular magnetic recording media has led to a need for high spatial resolution chemical analysis techniques. The properties of such materials depends critically on the composition profile across the layers and interfaces. Techniques which can be applied to analysis of MLF in cross-section are energy dispersive X-ray (EDS) or electron energy loss (EELS) analysis using a small probe scanning transmission electron microscope (STEM).A VG HB501 STEM at Oxford, fitted with a windowless EDS detector and an EELS detector has been modified to enable pulse counted digital X-ray and EELS maps (plus bright-field (BF) or annular dark-field (ADF) images) to be collected and stored for post-processing in the Semper image-processing package.
Application of ALCHEMI to the study of non-Stoichiometric Compounds
Authors: Munroe P.R. , Baker I. 
Published: June 2020

ALCHEMI, or atom location by channeling enhanced microanalysis, has been used to study the sublattice occupancy of trace elements in minerals and ternary additions to intermetallic compounds. ALCHEMI studies of intermetallic compounds have previously been performed on compounds which are at, or near to, stoichiometry, or where the ternary element has been added at the expense of one species. In these cases it is assumed that the sublattices are perfect. That is, in the compound AB + X, there are no A atoms on the B sublattice or vice versa.In compounds which are far from stoichiometry, which may include ternary additions, there may be A atoms on the B sublattice. For example in Ni-45Al (compositions given in atomic %) , 10% of the aluminum sublattice sites are occupied by nickel atoms; iron-rich FeAl alloys behave similarly. Thus if a nickel-rich NiAl thin foil is tilted to an orientation where the x-ray intensity of the aluminum sublattice is enhanced, there will be a concomitant enhancement of the nickel x-ray intensity due to the nickel atoms located on the aluminum sublattice.
A CBED Study of CuAgSS
Authors: Baker C.L. , Lincoln F.J. , Johnson A.W.S. 
Published: June 2020

The room temperature phase of the compound CuAgS occurs in nature as the mineral stromeyerite. Its structure is stable up to approximately 90°C, above this temperature it transforms to a cation disordered structure with copper and silver ions mobile through a hexagonal close packed sulphur lattice. The structure of stromeyerite has been investigated by single crystal X-ray diffraction and was found to have an orthorhombic unit cell with possible space groups Cmcm (63) or Cmc21 (36). The structure was refined in Cmcm but only to an R factor of 0.30. Refinement in Cmc21 was not attempted. The structure is important as a starting model for those of other phases in the system Cu-Ag-S and consequently more precise information was required.Synthetic CuAgS was prepared from the binary sulphides by solid state reaction in vacuo at 300°C for one week. It was then ground to a powder and annealed at 70°C in N2 for a month.
Critical Voltage for Non-Centro. Crystals and its Application to the Accurate Measurement of Structure Factor Phases by CBED
Authors: Spence J.C.H. , Zuo J.M. 
Published: June 2020

The application of the three-beam dynamical theory of transmission electron diffraction to centrosymmetric and non-centrosymmetric crystals shows that certain regions of three-beam CBED patterns are highly sensitive to the three-phase structure invariant By applying this method to the systematics geometry, a method has been described which allows structure factor phases to be measured with an accuracy of 0.07°. Using the Bethe potentials, we find a degeneracy in eigenvalues at the critical voltage VA for acentric crystals in the systematics orientation whereHere VA is now seen to depend both on the structure factors Vg (in volts) and on the systematics “two=phase” invariant In this paper we consider the application of this method to BeO (wurtzite structure), with g = (004) and h = (002). Then the CBED intensity is most sensitive to Y near the (004) Bragg condition at 46 kV. But since the theory contains only the product KSg, other voltages and orientations are also sensitive.
Characterization of Occurrence and Distribution of Invisible Gold in Ore by EPMA
Authors: Mao Shuihe 
Published: June 2020

Owing to the invisibility of ultramicron gold (invisible gold) in “Carl in type” gold ore, it is extremely difficult to investigate its occurrence and distribution by conventional determinative means.EPMA has been proved to be very powerful instrument for doing research on this subject because it has advantages of high space resolution, nondestructive,getting quantitative analysis results and observing various kinds of images continuously with same equipment etc.The unoxidized ore sample is selected from drill cuttings at a “Carlin type” gold mine in Southwest China with gold tenor of 31.02 g/t and weighs 2438g. The operating conditions of EPMA are: accelerating voltage 25kV, beam current 1×l0-8 A, beam diameter about 1 μm. AuLα but not AuMα is preferably chosen as analysed x-ray line, because AuMα 1 (5.840Å) is overlapping with the 3rd order line of FeKα (5.812Å) to some extent and iron is the main component of pyrite matrix. According to the expression of detection limit(CDL ), the calculated value of CDL under the circumstances is 0.038%.
Real-time observation of single molecules by confocal fluorescence microscopy
Authors: Nie Shuming , Chiu Daniel T. , Zare Richard N. 
Published: June 2020

The ability to detect, identify, and manipulate individual molecules offer exciting possibilities in many fields, including chemical analysis, materials research, and the biological sciences. A particularly powerful approach is to combine the exquisite sensitivity of laser-induced fluorescence and the spatial localization and imaging capabilities of diffraction-limited or near-field optical microscopes. Unlike scanning tunneling microscopy (STM) and atomic force microscopy (AFM), which lack molecular specificity, optical spectroscopy and microscopy techniques can be used for real-time monitoring and molecular identification at nanometer dimensions or in ultrasmall volumes.We report the use of confocal fluorescence microscopy coupled with a diffraction-limit laser beam and a high-efficiency photodiode for real-time detection of single fluorescent molecules in solution at room temperature. Rigler and Eigen have also demonstrated single-molecule detection with a confocal microscope and fluorescence correlation spectroscopy. The probe (or sampling) volume is effectively an elongated cylinder, with its radius being determined by optical diffraction and length by spherical aberration.
SNR gains with superconducting coils and hyperpolarized inert gas
Authors: Black R. D. 
Published: June 2020

Magnetic resonance microscopy (MRM) has advanced from a technical challenge to a practical tool in a wide range of basic sciences (1). The nondestructive nature of the technique allows for repeated studies of the same sample, retrospective studies through any arbitrary plane, registered studies using different contrast mechanisms, and examination of valuable specimens. "Proton contrast" is provided by making use of T1, T2, T1ρ , diffusion, and magnetization contrast weightings, thus permitting direct examination of the state of water in tissues; something not possible with other microscopic techniques. The technical hurdles imposed by a limited signal-to-noise ratio (SNR) have been partially overcome by improved RF coil design and by three dimensional Fourier transform encoding for large arrays. We have introduced two additional technologies that help to further redress this SNR deficit: superconducting RF coils and inert gas hyperpolarization.It has been argued elsewhere (2,3) that the dominant source of noise in the receiving chain for small objects in high fields is the pickup coil and the preamplifier.