bluuebunny/crossref_metadata_2025_split huggingface dataset:
SPC: What is It and Why Should You Use It in Your Xray Analytical Laboratory?
Authors: DeGroot P. B. 
Published: March 2019

AbstractStatistical Process Control (SPC) methods have become extremely popular in quality control and process improvement in the manufacturing environment, first in Japan and more recently in the U.S. They are gradually being introduced into the research and development setting as well, where they offer some advantages over more traditional statistical approaches. The greatest advantage of the SPC approach is that it ensures that the statistical description generated is valid, i.e., that the data on which it is based incorporate only random error. This is verified both initially and on a continuing basis. This means that the results provide valid predictions of future performance, not just a description of an historical set of replicate samples. SPC statistical evaluations of analytical results and instrument performance require only simple calculations and are easily applied in a consistent, valid manner by statistically unsophisticated analysts. Besides the numerical statistical analysis tools, the SPC approach provides other problem-solving techniques for improvement of the entire analysis process. These aspects of the SPC approach will be described and illustrated with examples from our x-ray fluorescence analysis laboratory.
X-ray Capillary Microbeam Spectrometer
Authors: Larsson S. , Engstrom P. , Rindby A. , Stocklassa B. 
Published: March 2019

AbstractBy utilizing the total reflecting properties of x-rays inside glass capillary tubes, intensive fine- or microbeams of x-rays can be attained. By using a conventional x-ray tube in combination with capillary technique, microbeams with a diameter of a few μm and with an intensity sufficient for trace elements, analyses have been achieved. By moving the sample, lineand areascan can be performed and trace element information can be directly superimposed on a micrograph from a built-in optical microscope.The background of the capillary technique is reviewed and an EDXRF microbeam spectrometer for trace elements is described. Examples of applications for the microbeam spectrometer are given.
X-Ray Diffraction Using Synchrotron Radiation - A Catalysis Perspective
Authors: Newsam J. M. , King H. E. , Liang K. S. 
Published: March 2019

AbstractSynchrotron X-radiation provides unique opportunities for diffraction experiments and, therefore, for extending our understanding of the structure - property interplay in catalyst systems. The present status of opportunities and applications of synchrotron X-ray diffraction techniques in the structural chemistry and catalysis science areas is overviewed, and illustrated by selected recent results.
The Determination of Rare Earth Elements in Geological Samples by XRF Using the Proportional Factor Method
Authors: Yuanpan Chen 
Published: March 2019

AbstractThis paper describes the principle, method and application of the proportional factor method for the determination of rare earth elements (REE) in geological samples by XRF, The analytical results of this method are compared with REE recommended values in geological standards, and good agreement was observed. Five of the REE (Pr, Tb, Ho, Tm and Lu) have also been determined by interpolation from chondrite-normalized plots, and more satisfactory results were obtained.
Impurity Analysis of Silicon Wafers by Total Reflection X-ray Fluorescence Analysis
Authors: Nomura Sigeaki , Nishihagi Kazuo , Tauiguchi Kazuo 
Published: March 2019

High purity of silicon wafers is demanded by the high performance and highly integrated IC and LSI semiconductors. Impurities on, or in, the silicon wafer have a big influence on the characteristics of the semiconductor as a final product. Usually, these impurities are introduced by water during washing, by bad handling, or by reagents and processes.Typical influences of these impurities are shown in Table 1. These elements are present at too small concentration to he detected by ordinary analytical methods (except for oxygen). Usually, XPS , AES, NAA, SIMS, ICPAES, ICP-MS and AAS are used for trace analysis.
X-ray Diffraction of Thin Oxide Films on Soldered Module Pins
Authors: Adi T. Paul , Stehmeyer H. F. 
Published: March 2019

AbstractThe presence of metal oxide films from wave solder baths on timed module pins are partly responsible for non-wet problems in subsequent soldering steps. The cylindrical geometry of the pins lends itself to the characterization of thin oxide films by using the highly sensitive Debye-Scherrer camera method. As confirmed by Electron Hicroprobe Analysis (EMA), pins containing thin oxide films were used to obtain the diffraction patterns. A software program was developed that subtracts the diffraction angles of an oxids-free control pin from the pattern of the contaminated pin, and tabulates the residual d-spacing (interplanar distance) of the contaminant film.
Residual Stresses in Al2O3/SiC (Whisker) Composites Containing Interfacial Carbon Films
Authors: Abuhasan Alias , Predecki Paul K. 
Published: March 2019

AbstractResidual strains and stresses were measured in hot-pressed α-Al2O3 composites containing 25 wt% β (cubic) SiC whiskers with and without a 50-100Å thick carbon coating. X-ray diffraction methods were used including the separation of macrostresses from the microstresses in the -Al2O3 and SiC phases by the method of Noyan and Cohen. The presence of the carbon coating on the whiskers reduced the magnitude of the residual microstresses in the whiskers by ˜13% and in the matrix by ˜10%. The measured residual stresses in the whiskers and the reduction due to the carbon film were in good agreement with calculations from recent models proposed by Hsueh, Becher and Angelini, and by Li and Bradt.
Parameters Affecting X-Ray Microfluorescence (XRMF) Analysis
Authors: Nichols Monte C. , Boehme Dale R. , Ryon Richard W. , Wherry David , Cross Brian , Aden Gary 
Published: March 2019

AbstractX-ray Microfluorescence (XRMF) analysis uses a finely collimated beam of X-rays to excite fluorescent radiation in a sample (Nichols & Ryon 1986). Characteristic fluorescent radiation emanating from the small interaction volume element is acquired using an energy dispersive detector placed in close proximity to the sample. The signal from the detector is processed using a computer-based multi-channel analyzer.XRMF imaging is accomplished by translating the sample through the small X-ray beam in a step or continuous raster mode. As the sample is translated, a pixel by pixel X-ray intensity image is formed for each chemical element in the sample. The resulting digitized image information for each element is stored for subsequent processing and/or display. The images, in the form of elemental maps representing identical areas, may be displayed and color coded by element and/or intensity and then overlayed for spatial correlation.The present study of parameters affecting the performance of an X-ray microfluorescence system has shown how such systems use X-ray beams with effective spot sizes less than 100 micrometers to bridge the gap in analytical capabilities between predominately surface micro analytical techniques such as SEM/EDX and bulk analytical methods such as standard XRF analysis. The combination of XRMF spectroscopy with digital imaging allows chemical information to be obtained and mapped from surface layers as well as from layers or structures beneath the sample surface. Simultaneously, it provides valuable high resolution chemical information in a readily interpreted visual form which displays the homogeneity within a given layer or structure. XRMF systems retain the advantages of minimal sample preparation, non-destructive analysis and high sensitivity inherent to XRF methods.
Monte Carlo Simulation of the X-Ray Fluorescence Spectra from Multielement Homogeneous and Heterogeneous Samples
Authors: Yacout A. M. , Gardner R. P. , Verghese K. 
Published: March 2019

AbstractA Monte Carlo model that predicts the entire photon, spectrum for energy-dispersive X-ray fluorescence (EDXRF) analyzers excited by radio-isotope sources from multielement homogeneous samples is developed and demonstrated. The components of the photon spectrum include: (1) the and Kα and Kβ characteristic primary, secondary and tertiary X rays from both the unscattered and scattered source photons, (2) the characteristic X rays excited by other characteristic X rays that have been scattered, and (3) the scattered source photons from single, double, and multiple scatters in the sample.The computer code NCSMCXF based on this model has been developed. It is capable of handling up to 20 elements per sample and provides a detailed account of the intensities of the X rays and backscattered source photons per unit source decay as well as a summary of the relative intensities from all elements present in the sample. Cubic splines are used within the code for photoelectric and total scattering cross sections and two-variable cubic splines for angular coherent and incoherent scattering distributions for efficiency in both computation time and storage. The code also provides the pulse-height spectrum of the sample by using the appropriate Si(Li) detector response function. The Monte Carlo predictions for benchmark experimental results on two alloy samples of known composition indicate that the model is very accurate. This approach is capable of replacing most of the experimental work presently required in EDXRF quantitative analysis.A previous Monte Carlo model that uses the simple assumption of spherical homogeneous particles to approximate sample heterogeneities has been modified to improve the computer execution time requirements for the heterogeneous sample case. A new technique for photon tracking in this medium is used and reduces the computation time requirement by half.
A Quantitative Texture Analysis of Pluri-Crystals by Texture Goniometry
Authors: Vadon A. , Heizmann J. J. , C. Laruelle  
Published: March 2019

To understand how a material evolves - its crystal growth, topotaxy, twinning, phase transformation, plastic deformation, microstress, etc. - it is important to know the crystal orientations, either between them or in respect to the sample.The crystal texture of the material is quantified by the Orientation Distribution Function (O.D.F.). This function represents the part of the material volume having a given orientation. To compute this O.D.F, we must first measure one or several complete or incomplete pole figures and then analyse them either with Roe-Bunge's harmonic method or with Vadon, Ruer, Baro's vector method. In the case of a very sharp texture, the results obtained with the harmonic method are not good because developing a DIRAC function in spherical harmonics requires a high rank, hence a large number of pole figures. On the contrary, with the vector method, the results are good since discretizing amounts to developing on a step-function basis.
Dosimetry of X-Ray Beams: The Measure of The Problem
Authors: de Castro Ted 
Published: March 2019

While x-ray dosimetry is most definitely a "Measure of the Problem" in Analytical X-Ray Safety, there are additional factors which further enlarge the problem and are equally major considerations which must be taken into account when deciding upon the degree of action appropriate to prevent this problem.Certainly, some idea of the nature of the typical levels of natural and man-made sources of radiation which surround us daily is useful to give us a perspective on the magnitude of radiation levels from analytical x-ray equipment. It is also important to know what levels of radiation exposure are considered unacceptable, either by regulatory limits or because of the potential for physiological damage.The consequences of an exposure to radiation from analytical x-ray machines will often go beyond a report of an overexposure and investigation, or painful and lasting physiological damage. There are times when the matter will come before our courts in order to fix responsibility and decide compensation for injuries suffered.
Microstructural Characterization of Thin Polycrystalline Films by X-Ray Diffraction
Authors: Wagner C.N.J. , Boldrick M.S. , Keller L. 
Published: March 2019

AbstractThe Fourier analysis of the broadened profiles in a powder pattern allows the determination of the effective particle or domain size and the microstrains within each domain in polycrystalline materials. In order to apply this method to the diffraction patterns of thin films and coatings, deposited on crystalline or amorphous substrates, special diffraction techniques must be employed for the registration of the relatively weak intensities. The fitting of the experimental profiles to pseudo-Voigt functions permits the recovery of the peak tails and a precise determination of the background. The positions of the peak maxima or centroids yield information about any compositional variations, and about the occurrence of stacking faults and residual stresses in thin films and coatings.
Problems and Solutions in Quantitative Analysis of Complex Mixtures by X-Ray Powder Diffraction
Authors: Bish David L. , Chipera Steve J. 
Published: March 2019

AbstractIn spite of the wide availability of automated diffractometers and advanced data reduction software, numerous traditional problems still exist that make highly precise and accurate quantitative analyses of complex mixtures difficult. The problems include particle statistics, primary extinction, microabsorption, preferred orientation, overlapping and broad reflections, variation in standard data with composition, availability of pure standards, and detection of amorphous and trace phases. Our analyses of rocks use the matrix flushing method on < 5μm particle-size material mixed with a 1.0-μm corundum internal standard to minimize the first four effects. Integrated intensities are used, and we employ several peaks from each phase whenever possible. We overcame overlap problems through iterative calculations using integral, multiple peaks or with profile refinement. Use of observed and calculated diffraction patterns for every phase enables us to predict the effects of composition and preferred orientation on RIRs. This allows us to correct for these effects if reference intensity ratios (RIRs) are known as a function of composition and orientation. Detection of amorphous phases is a significant problem, and standard mixtures reveal that amounts of amorphous components below 30% are difficult to detect. The poor detection limit and the nature of the diffraction band from amorphous phases make internal standard or spiking methods the best approach for analyzing samples containing amorphous materials. The Rietveld method of quantitative analysis has the potential to minimize all of the above problems. This method requires a knowledge of the crystal structures of all component crystalline phases, but no calibration data are necessary, structural and cell parameters can be varied during the refinement process, so that compositional effects can be accommodated and precise cell parameters can be obtained for every phase. Since this method fits the entire diffraction pattern and explicitly uses all reflections from every phase, complex, overlapped patterns can be easily analysed. In addition, this method presents the opportunity to correct for preferred orientation and microabsorption during data analysis.
Measuring Graphitic Carbon and Crystalline Minerals in Coals and Bottom Ashes
Authors: Wertz David L. , Collins Leo W. , Froelicher Franz 
Published: March 2019

AbstractThe use of coal, as either a primary energy source or as a source of feedstock chemicals, has been complicated by the noxious and toxic chemical species formed in its gaseous effluents and also by the huge quantities of ash vhich result from its processing. Both the noxious gases and the ash have been the subjects of Federal legislations.X-ray powder patterns (XRPP), composed of atom-pair and self x~ray scattering and the diffraction produced by crystalline phases, have long been used to investigate coals and particularly their combustion ashes (1-3). Over twenty different crystalline phases have recently been reported to exist in certain lignite fly ash (3). Analysis of the crystalline phases has typically been emphasized in previous papers involving coals and ashes, but the amorphous scattering has been given little treatment.
X-Ray Study of the BaO-Y2O3-CuOxSystem
Authors: Wong-Ng W. , Roth R. S. , Beech F. , Davis K. L. 
Published: March 2019

AbstractTen compounds are found in the Ba0-Y203-CuOxsystem. High temperature (≈950-1000°C) phases identified as Ba4Y2O7, Ba2Y2O5, Ba3Y4O9, BaY2O4, Y2Cu2O5, BaCuO2+x, Ba3YCu2OZBaY2Cu05and BazYCu306+xare formed in this temperature range. In addition, a new compound with composition of 2BaO:CuO, which possibly has a melting point below 950°C, was prepared at 850°C. A summary o£ the crystallographic data of these 10 phases is given. In particular, results of x-ray studies pertaining to four compounds, BazYCu306+x, which is currently the most promising high To' superconductor material, Ba2Cu03, BaY2Cu05, and Ba3YCu20Zare reviewed.
Neutron Diffraction - A Probe for Grain Size and Preferred Orientation in Zircaloy-Clad Uranium
Authors: Richardson James W. , Mueller Melvin H. , Schultz Arthur J. , Ross Frederick K. , Reichel Daniel G. 
Published: March 2019

AbstractA recent goal of the ANL Intense Pulsed Neutron Source (IPNS) has been the fabrication of a new enriched uranium target with increased neutron flux (by a factor of 3) which is dimensionally stable under irradiation. Neutron diffraction, using several instruments both at IPNS and MURR, has been used as a probe to characterize the target material vith respect to grain size and preferred orientation. The samples studied were portions of the uranium discs (4" diameter X 1/2" thick) which, when stacked, form the target assembly at IPNS. The old target discs were fabricated as slices from a fast cooled casting (arc-melted, water cooled in a cylindrical mold) and possess small grain size and negligible orientation. The new enriched target discs, on the other hand, are being fabricated from a slow cooled material (graphite book-mold, natural cooling) and, prior to additional treatment, have a large grain size and a high degree of preferred orientation which could produce dimensional changes during fission as the target is used. Our conclusion from this investigation is that a β-phase heat treatment (quench from 730°C) is necessary to produce a finer grain and more nearly random texture in thg new enriched material. Based on our detailed texture measurements the anticipated target lifetime of several years appears feasible.
Near-Surface Analysis of Semicondutor Using Grazing Incidence X-Ray Fluorescence
Authors: Iida Atsuo , Sakurai Kenji , Gohshi Yohichi 
Published: March 2019

SummaryThe X-ray external total reflection was used for the x-ray fluorescence analysis of the near surface layer of a GaAs wafer and a GaAlAs epilayer. Synchrotron radiation was used as an excitation source. The intensity ratio between the Ga K and As K fluorescence signals was measured as a function of the glancing angle. The reduction of As atoms near the surface of less than a hundred Å was observed for the high temperature annealed GaAlAs epilayer.
Development of μ-Fluorescent and Diffracted X-Ray Spectrometer with a Fine Focused X-Ray Beam and its Application for Ulsi Microanalysis
Authors: Yamamoto Naoki 
Published: March 2019

A fluorescent and diffracted X-ray spectrometer with an X-ray sub-micron beam was developed for the analysis of stress, crystal structure, and contamination in micro-regions of ULSIs. A fine glass capillary with a parabolic cross-sectional inner wall surface was made to form a micro X-ray beam. A micro-focus X-ray generator with a membrane-type target was also developed for use with the capillary. The equipment was used to analyze the crystal phases of Ti silicide fine lines and the strains in Al interconnections.The resistance of Ti-silicide lines increases the line width narrows under about 0.5 μrn. This is because of the growth of crystal phases of TiSi2(C49) and TiSi(B27) with high resistivity ﹛60 to 100 μΩ-cm).Hillocks of Al grow at line edges when Al layers are compressed by Si substrates and surrounding insulating layers. On the other hand, when the Al is extended by these layers, voids form in the AI lines.
Anti-CD24 Antibody–Nitric Oxide Conjugate Selectively and Potently Suppresses Hepatic Carcinoma
Authors: Sun Fumou , Wang Yang , Luo Xiaojun , Ma Zhaoxiong , Xu Yao , Zhang Xinrong , Lv Tian , Zhang Yihua , Wang Min , Huang Zhangjian , Zhang Juan 
Published: March 2019

AbstractNitric oxide (NO) has a wide range of potential applications in tumor therapy. However, a targeted delivery system for NO donors has remained elusive, creating a bottleneck that limits its druggability. The antibody–drug conjugate (ADC) is a targeted drug delivery system composed of an antibody linked to an active cytotoxic drug. This design may compensate for the weak targeting ability and various biological functions of the NO donor. In this study, we designed the NO donor HL-2, which had a targeted, cleaved disulfide bond and an attachable maleimide terminal. We conjugated HL-2 with an antibody that targeted CD24 through a thioether bond to generate an ADC-like immunoconjugate, antibody-nitric oxide conjugate (ANC), which we named HN-01. HN-01 showed efficient internalization and significantly increased the release of NO in hepatic carcinoma cells in vitro. HN-01 induced apoptosis of tumor cells and suppressed tumor growth in hepatic carcinoma-bearing nude mice through antibody-dependent co-toxicity; HN-01 also increased NO levels in tumor cells. Collectively, this study expands the concept of ADC and provides an innovative NO donor and ANC to address current challenges in targeted delivery of NO. This new inspiration for an ANC design can also be used in future studies for other molecules with intracellular targets.Significance:This study is the first to expand the concept of ADC with an antibody-nitric oxide conjugate that suppresses hepatic carcinoma in vitro and in vivo.
Immunotherapy of Melanoma: Facts and Hopes
Authors: Weiss Sarah A. , Wolchok Jedd D. , Sznol Mario 
Published: March 2019

Abstract
Melanoma is among the most sensitive of malignancies to immune modulation. Although multiple trials conducted over decades with vaccines, cytokines, and cell therapies demonstrated meaningful responses in a small subset of patients with metastatic disease, a true increase in overall survival (OS) within a randomized phase III trial was not observed until the development of anti–CTLA-4 (ipilimumab). Further improvements in OS for metastatic disease were observed with the anti–PD-1–based therapies (nivolumab, pembrolizumab) as single agents or combined with ipilimumab. A lower bound for expected 5-year survival for metastatic melanoma is currently approximately 35% and could be as high as 50% for the nivolumab/ipilimumab combination among patients who would meet criteria for clinical trials. Moreover, a substantial fraction of long-term survivors will likely remain progression-free without continued treatment. The hope and major challenge for the future is to understand the immunobiology of tumors with primary or acquired resistance to anti–PD-1 or anti–PD-1/anti–CTLA-4 and to develop effective immune therapies tailored to individual patient subsets not achieving long-term clinical benefit. Additional goals include optimal integration of immune therapy with nonimmune therapies, the development and validation of predictive biomarkers in the metastatic setting, improved prognostic and predictive biomarkers for the adjuvant setting, understanding mechanisms of and decreasing toxicity, and optimizing the duration of therapy.