bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identifying Molecular Counterparts of Functional Gradients in Biomaterials
Authors: Herbert Waite J 
Published: July 2020

Abstract
many naturally occurring structures are, in fact, composite materials with functionally graded mechanical properties. in manufacturing, achieving such graded properties is critical when joining two materials of significantly different elastic moduli, thermal or electronic characteristics. One assumes that similar imperatives are at play in the profusion of biological examples of gradients. Two gradient biosystems, in particular, have been the focus of our attention: These are mussel byssal threads and polychaete jaws. Mussel byssal threads are composites consisting of anisotropically packed discontinuous fibers in an amorphous matrix all coated by a protective cuticle. The threads are produced by process resembling reaction injection molding and imparted with a longitudinal gradient of mechanical properties ranging from stiff and tough distally to extensible and rubbery proximally. Collagen is the principal tensile polymer as determined by fiber x-ray diffraction, however, the mechanical properties of typical tendon are poorly matched with those of byssal threads.
Relation Between Shear Viscosity and Morphology in Lung Surfactant Monolayer
Authors: Ding Junqi , Warriner Heidi E , Zasadzinski Joseph A 
Published: July 2020

Abstract
The primary function of lung surfactant monolayers (LS) is to control and reduce surface tension in the lung permitting easy breathing. to do this, the monolayer must maintain coverage of the entire lung surface during the rapid surface area changes which accompany breathing. We use a magnetic needle viscometer and optical microscopy to determine the relationship between monolayer shear viscosity, which controls its two-dimensional flow properties, and synthetic lung surfactant composition. We show that, within a specific range, palmitic acid interacts with DPPC/POPG to make lung surfactant rigid at low surface tension (or high surface pressure) and fluid at high surface tension. This enables the monolayer to attain near zero surface tensions during compression yet respread easily at high surface tension More palmitic acid makes the monolayer more rigid and eventually increases the collapse surface tension while reducing the readsorption rate at high surface tension.
Effects of Spaceflight on Cultured Bone Cells
Authors: Landis WJ 
Published: July 2020

Abstract
Bone is known to alter its architecture, mass, composition, metabolic state, development and function in response to the effects of external forces applied to it, whether those forces be loading or unloading in nature (1). These adaptive changes by bone and the vertebrate skeletal system in general may be imparted by mechanical forces, gravity, buoyancy, or other such influences and manifest themselves in a number of ways. The skeleton of an animal, for example, may increase in mass through exercise and heightened activity, it may lose mass as a result of extended immobilization or weightlessness, or it may remodel during fracture repair processes. A mechanism explaining the adaptation by bone and the skeleton to the presence or absence of applied forces is not completely understood, but the changes are thought to occur ultimately at the cellular level of structure. Studies presented here have examined the relationship between forces and bone cell response in this context: Spaceflight and weightlessness have been utilized to investigate the influence of gravitational unloading on a model of cultured osteoblasts derived from normal embryonic chicken calvaria.
Vascular Tissue Engineering Utilizing Electrospun Matrices: Microscopic Evaluations
Authors: A. Matthews Jamil , E. Wnek Gary , G. Simpson David , L. Bowlin Gary 
Published: July 2020

Abstract
The development of a seamless, collagen-based vascular prosthetic scaffolding (&lt; 4 mm I.D.) has been accomplished using an electrospinning fiber production technique (Patents Pending). Electrospinning is the deliberate application of the phenomenon of electrostatic spraying which occurs when electrical forces at the surface of the polymer solution overcome the surface tension, creating a splay. The splay produces fibers with diameters in the nano-scale range (&lt;500 nm). The collagen-based scaffold production method (flexible, quick, and simple) utilizes the splaying of the collagen-based solution from a nozzle to a grounded rotating mandrel (4 mm O.D. cylindrical mandrel for the preliminary vascular tissue engineering). in splaying, the solvent evaporates creating nano-scale fibers of polymerized collagen (and elastin in some variations). The collagen fibers are collected on the mandrel forming a cylindrical tube (media equivalent scaffolding). to date, mixtures of collagen containing Type I and 80:20 Type l/Elastin have been utilized to produce vascular scaffolds of various thickness (50 - 2,000 microns).
Role of Raman Microprobe Spectroscopy in the Characterization of Microelectronic Materials
Authors: Klymko NR , Casey JA , Tai L , Fitzsimmons JA , Adar F 
Published: July 2020

Abstract
The production of semiconductor chips and packaging materials involves the use of a wide array of materials, from solvents and polymers, to photoresists, to metal and dielectric layers, to conductive and thermal pastes. Characterization of these materials, both in raw form and as formulated for in-process use, is integral to successful use of them in microelectronic manufacturing. Physical and chemical analytical techniques are employed to determine parameters such as composition, cure state, and interface chemistry. More often than not, it is the successful combination of complementary analyses which provide the complete understanding of material parameters needed.
This paper reports the use of Raman microprobe spectroscopy as a characterization technique for microelectronic materials. Several examples will be given, illustrating the type of information which can be obtained and the complementary use of Raman spectroscopy in conjunction with other analytical techniques such as Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) to characterize microelectronic packaging materials and organic materials used in semiconductor manufacture.
Application of Confocal Laser Imaging Microscopy and Raman Spectroscopy to Particle Characterization in Semiconductor Industry
Authors: Conti Giuseppina , Uritsky Yuri 
Published: July 2020

Abstract
The analytical needs in semiconductor technology have developed according to the increasing demands imposed by size and complexity. Early optical visualization, localization and counting of ever-smaller particles extended almost immediately to their morphological and chemical characterization. This evolution was due to the shifting balance from quality control to root-cause analysis. Root-cause analysis requires a deeper analytical approach to the characterization of the observed defects. Atomic composition may suffice at times as an answer. However, this information may be ambiguous and inadequate. Therefore, deeper chemical information regarding molecular structure and crystallinity of the particle is now required.
The analytical capabilities and versatilities associated with optical spectroscopy inevitably have led to their increasing applications in the semiconductor industry. in particular, the complementary Infrared and Raman spectroscopies on one hand provide huge insight into the molecular structure and crystallinity of the particles, on the other hand Raman and Photoluminescence (PL) spectroscopies are easily coupled to systems providing particle visualization and localization.
The Partition Layer of Common Bunt Teliospores
Authors: Hess WM , Weber DJ 
Published: July 2020

Abstract
The basidiomycete fungus, Tilletia constitutes the most important group of smuts economically as they infect cereal grains which provide a major portion of the world’s food supply. The teliospores of the smuts which have been studied have a spore wall layer called the partition layer or the striated zone which is very resistant to fixatives and resins used for electron microscopy. We assume that the chemical nature of this wall layer is the primary factor to prevent spore desiccation and to maintain spore viability for many years. Teliospores of Tilletia tritici (Bjerk.) Wint. (formerly T. caries), T. controversa Kühn, T. indica Mitra, and Neovossia horrida (Tak.) Padwick and Khan all have a reticulated exterior spore layer (sheath). Common bunt, Tilletia laevis Kühn (formerly T. foetida) teliospores lack this exterior reticulated layer, but are also resistant to spore desiccation and maintain viability for many years. Therefore, the purpose of this study was to compare the ultrastructural characteristics of the partition layer of T. laevis teliospores with the partition layer of other teliospores of smut fungi which have been studied.
Nipah Virus and Other Emerging Pathogens: The Role and Importance of Electron Microsccopy
Authors: Hyatt AD 
Published: July 2020

Abstract
When it is all said, done, celebrated and published, the question remains, “How do we identify new viruses?” How do we build preparedness for rapid identification and teams whereby important data can be disseminated to our peers in virology, histopathology and molecular biology? The answers lie in the ability to build effective teams and to recognize the unique contributions of disciplines such as electron microscopy and the associated skill bases. The success in Australia for the rapid and accurate identification of new viruses has, in the main, been attributed to the effective use of electron microscopy. Data generated from such investigations have provided the foundation for subsequent studies involving the above areas of diagnostic inquiry. Data presented in this paper overviews some of the successes of electron microscopy and highlights its continued role in the identification of ‘emerging pathogens’ that have potentional impact on trade, human health, medical health and conservational biology.
Estimation of Electron Beam Broadening in Specimen for Analytical Electron Microscopy
Authors: Lee C-W , Kidu S , Oikawa T , Shindo D 
Published: July 2020

Abstract
The electron beam broadening in specimens is a important issue to obtain a high spatial resolution expected by using a fine electron probe of nanometer order in analytical electron microscopy. Beam broadening mainly depends on electron diffusion in specimens. The theoretical equation on the beam broadening, which is based on single scattering approximation model for incident electrons, has been proposed by Goldstein et al.. in this work, the beam broadening was estimated experimentally by a TEM equipped with a field emission gun and the results were compared with the values theoretically obtained.
The sizes of the beam diameter with and without specimens were measured by using JEM-2010F and JEM 3000F TEMs, which are equipped with a field emission gun, being operated at 200 and 300 kV, respectively. The beam diameter was defined as the diameter containing 90% of the total electrons. The specimens used were amorphous SiO2, crystalline MgO and Si.
Progress with the IBM Very High Resolution STEM
Authors: Batson RE , Mook HW , Kruit P , Krivanek OL , Dellby N 
Published: July 2020

Abstract
The IBM high resolution STEM project has now reached the point where integration of new subsystems into the instrument is the main activity. During the past three years, we have demonstrated a 50meV EELS resolution using a high brightness electron monochromator incorporated into the electron gun [1, 2, 3], and better than 0.14mn spatial resolution using spherical aberration correction at 120KeV. [4] Recent effort has been to identify and remove many sources of instabilities in the original instrument; to rebuild several existing subsidiary pieces of equipment such as the ADF detector, the EELS spectrometer electron optical coupling, and the EELS CCD detection system; and to set up software and hardware control of each system to allow routine operation.
The new STEM column is summarized in Fig. 1. Briefly, the original VG gun flange has been lowered about 4cm, using a spacer, to allow insertion of the Fringe Field monochromator.
Substitutional Impurity Segregation to the Σ 5 (310)/[001] Stgb in Cu Doped Aluminum and Ag Doped Copper
Authors: Plitzko J M , Campbell G H , King W E , Foiles S M , Kisielowski C 
Published: July 2020

Abstract
The phenomenon of segregation is of long standing scientific interest and has been studied extensively, both theoretically as well as experimentally. For our investigations we have chosen the Σ5 symmetric tilt grain boundaries (STGB) in two face-centered cubic (FCC) metals, aluminum and copper. Both metals were doped with only 1 at% of the impurity species (Cu and Ag). One of our major goals in this study was to investigate the size effect on segregation of an impurity to distinct sites at the grain boundary. Therefore we have selected the Ag as an impurity in Cu and Cu as an impurity in Al. The latter one is of special interest for applications like interconnects in microcircuits, where one of the major controlling factors of electromigration is expected to be the diffusion or segregation of Cu atoms at Al grain boundaries.
The model grain boundaries have been fabricated with ultra-high vacuum diffusion bonding of single crystals which bonds the bicrystals under highly controlled environmental conditions.
Quantitative Field-Emission Transmission Electron Microscopic Study of Domain Boundaries in Cerium Doped A-Sialon Materials
Authors: Xu F , Bando Y , Wang C , Mitomo M 
Published: July 2020

Abstract
α-sialon is the isostructural derivative based on the a-silicon nitride (α-Si3N4) structure by partial replacement of Si by Al and N by O. The structure is considered to be stabilized by the incorporation into the large interstices (r=0.146nm) of a metal like Li, Mg, Ca and most small rareearths. Large rare-earth metal ions have been considered not to be able to enter the interstices in α-sialon structure until several recent successes in accommodating large cerium ions (r=0.103nm). This gives rise to questions of the location and distribution of these large cerium ions within the asialon structure. It has been found that α-sialon grains formed in Ce-Si-Al-O-N system are usually rich in a new structural defect which has been considered to be initiated specifically by the presence of cerium in the lattice. This new intergrown defect is identified as domain boundary in our present study by transmission electron microscopy (TEM).
Structural Characterization of Vanadium Carbide Using Core Ionization Electron Energy Loss Spectroscopy (Cieels) in Transmission Mode
Authors: González-Valenzuela C , Espinosa-Magaña F , Paraguay D. F , Duarte-Moller A 
Published: July 2020

Abstract
Vanadium carbide was purchased as powder at Aldrich with a 99.9% pure. Sample was prepared in the standard method for powder observation in a TEM.EELS experiments were carried out in a Phillips CM 200 STEM equipped with a Gatan 766 PEELS spectrometer. Experimental conditions for acquiring were the follows: a spot size of 500 nm, a chamber length of 400 mm and a detector aperture of 3 mm using a energy dispersion of 0.3 eV/channel with a beam energy of 200 KeV. Acquisition time was around 10 mn. taking an average of 100 spectra.
All the EELS spectra were corrected for background subtraction and multiple scattering deconvolution, before the fine structure analysis. The fine structure range was about 200 eV beyond the C-K edge located at energy loss of 283.8 eV and respect to the VL23-edge located at a energy loss of 513 eV.
On Lensless Imaging of Organics with Neutrons, X-Rays, Helium Atoms and Low Energy Electrons: Damage and Iterative Phase Retrieval
Authors: Spence JCH , Weierstall U , Fries J 
Published: July 2020

Abstract
Recent experiments with X-rays and high energy electrons have shown that image recovery from diffracted intensities is possible for non-periodic objects using iterative algorithms. Application of these methods to biological molecules raises the crucial problem of radiation damage, which may be quantified by Q = ΔE σi/σe, the amount of energy deposited by inelastic events per elastic event. Neutrons, helium atoms and low energy electrons below most ionization thresholds produce the smallest values of Q (see for TMV imaged at 60 eV). For neutrons (λ = 10-2Å, and deuterated, 15N-abelled molecules) Q is ∼3000 times smaller (∼50 times for λ = 1.8Å) than for electrons (80- 500keV) and about 4x 106 times smaller than for soft X-rays (1.5Å). Since σe for neutrons is about 105 times smaller than for electrons (and about 10 times smaller than for soft X-rays), a 105 times higher neutron dose is required to obtain the same S/N in a phase contrast image compared with electrons, if other noise sources are absent.
Light Atom Sensitivity of Quantitative HREM
Authors: Möbus G 
Published: July 2020

Abstract
Introduction: Modern TEM/STEM instruments with field emission gun and various analytical equipment allow the measurement of interfacial properties by a range of modes and techniques without exchanging the specimen. It is therefore useful to think of a criterion to assess the sensitivity of each technique, e.g. for the location of light atoms, by a commonly applicable formula.
Sensitivity measures: A “quantitative” TEM experiment is defined here as consisting of a digital comparison (e.g. via data difference or cross correlation) between experimental (E) and simulated (S) microscopy signal. The matching quality R = f(E,S) is to be optimised (minimum for data difference, maximum for cross correlation). The target quantity of the Q-TEM experiment is assumed to be the location or occupancy of a light atomic column in projection surrounded by heavier atoms in the core of an interface making use of dynamical enhancement effects.
An Interferometric Electron Ruler with Picometer Accuracy in Gauaging Lattice Displacement
Authors: Wu Lijun , Zhu Yimei , Tafto J 
Published: July 2020

Abstract
We report a novel technique to accurately measure interfacial lattice displacement by forming an electron probe close to a specimen in a manner similar to that originally proposed by Gabor to record a hologram. This method is based on the quantitative analysis of the interference pattern of shadow images in coherent electron diffraction. The approach is unique in that there are no adjustable microscope parameters, the contrast is strong even when the fault is viewed edge-on, and a large number of shadow images of the fault corresponding to different Bragg reflections can be studied simultaneously. Since it is an interferometric technique, the spatial resolution of the measurement is not limited by the wavelength of the fast electrons. An accuracy down to 1pm has been demonstrated in measuring the displacement associated stacking faults and grain boundaries in superconductors. It is, to our knowledge, the highest that has been achieved in measurements of displacement vectors.
Predictive Structure-Property Correlations for SrtiO3 Grain Boundaries
Authors: Prabhumirashi Pradyumna L , Johnson Kevin D , Dravid Vinayak P 
Published: July 2020

Abstract
In polycrystalline materials the trapping of charge at interfaces has a decisive influence on the electrical transport properties through the formation of electrostatic potential barriers. This can either be an intrinsic phenomenon or can be related to impurity segregation leading to complex defect centers. This plays a key role in technologically important systems, especially those having electrically active interfaces, e.g.,p-n junctions in semiconductors and grain boundaries in electroceramics.
Electroceramic oxides such as ZnO and SrTiO3 are common systems that exhibit the tendency of current control by internal potential barriers. While bulk measurements, either electrical (e.g. P-E, C-V, I-V), or optical (e.g. Raman) have contributed significantly to the understanding of charged interfaces, there are a very few direct observations of electrical activity at a nanometer level. For instance, it has been recognized that space charge and dopant segregation at the grain boundary are inter-related.
Quantitative EFTEM of Cr Grain Boundary Segregation in Cocrta
Authors: Wittig JE , Al-Sharab JF , Bentley J , Evans ND , Nolan TP , Sinclair R 
Published: July 2020

Abstract
Grain boundary Cr segregation provides magnetic isolation between the crystals in sputtered Co thin films used for longitudinal magnetic recording. Magnetic isolation decouples individual grains in order to increase coercivity, lower media noise, and allow for higher recording densities. These sputtered Co alloys grow with a strong [1120] texture owing to a body centered cubic (BCC) Cr underlayer. The sputtered Cr seed-layer has a [001]BCC growth texture and the BCC {110}cr planes lattice match with the hexagonal (0002)cr planes. This produces the desired condition of the easy axis of magnetization, [0001]co, in the plane of the magnetic layer. However, since two orthogonal orientations of the {110}cr planes exist parallel to the [001]cr growth direction, it is possible to nucleate two hexagonal Co grains with orthogonal variants of the c-axis that will impinge to form a 90° grain boundary. The well defined crystallographic texture of the Co-alloy thin film with random angle and 90° grain boundaries presents an opportunity to study the effects of boundary character on Cr segregation in hexagonal crystals.
Energy Loss Fine Structure Studies of Temper-Embrittled Lowalloy Steel
Authors: Papworth AJ , Williams DB 
Published: July 2020

Abstract
Temper-embrittlement in low-alloy steel has been attributed to the segregation of elements to the prior austenite grain boundary (PAGB). Auger electron spectroscopy (AES) has shown that the embrittlement of the PAGB is due to phosphorus segregation. The problem with this type of analyses is that only the PAGBs that fracture can be analyzed. More recent X-ray studies in a field emission gun scanning transmission microscope have shown that molybdenum, nickel, chromium manganese and phosphorus all segregate to PAGBs, and that these elements can be classified into two segregation groups; those PAGBs that contain nickel, manganese and phosphorus and those PAGBs that contain molybdenum, chromium and phosphorus. AES cannot determine conclusively, which segregation group is responsible for the embrittled PAGBs. The measurement of how embrittled the low-alloy steel has become, requires the knowledge, which PAGBs are embrittled and the percentage of these boundaries within a given volume.
Non-Stoichiometry at Dislocation Cores in Perovskites and Related Materials
Authors: Duscher Gerd , Kim M , Browning ND , Christen D K , Cantoni C , Pantelides S T , Pennycook S J 
Published: July 2020

Abstract
Z-contrast images and electron energy loss spectra (EELS) were obtained from low angle grain boundaries in SrTiO3 and YBa2Cu3O7-x (YBCO). Z-contrast images are easy to interpret and especially useful for positioning the beam to acquire EELS data from small sample areas [1], because both these techniques can be performed simultaneously.
In high-temperature superconductors even a single grain boundary can reduce the critical current by up to four orders of magnitude. The band-bending model can quantitatively explain this phenomenon. YBCO is a hole-doped superconductor with about one hole per unit cell for optimum doping at x close to zero. It has a structure closely related to the perovskite structure, and Z-contrast images have shown that the dislocation cores are made up of similar structural units as in SrTiO3.[2,3] Our EELS measurements show clear evidence for band bending effects around isolated dislocation cores in an undoped 8° low angle grain boundary.