Singular Face Research Articles

Imaging of micro-steps on as-grown surface of sapphire with X-ray phase contrast technique

Basal-faceted sapphire ribbons grown using the Stepanov–LaBelle technology have a low density of surface steps. We present our results on a study of steps on the surface of a ribbon, misoriented relative to the singular face (0001) by several arc minutes. The ribbon has been characterized by means of in-line phase contrast imaging technique at Pohang Light Source, South Korea. It was shown for the first time that a step height of about 1 μm can be determined directly from an image. The step height obtained using the phase contrast method was confirmed by atomic force microscopy measurements. We have found that the experimental contrast matches the theoretical simulations only if the calculated intensity profile has been convolved with a Gaussian function. The full width at half maximum of the Gaussian was independently got from previous measurements. We have obtained an analytical solution in the case of theoretical fully coherent phase contrast image. The inverse problem is easy to solve, since there is a direct proportionality between the contrast and the step height.

О стабильности капель катализатора на границе контакта пар-жидкость-кристалл в процессе роста нитевидных нанокристаллов

The paper provides a physical justification for the wettability conditions for a crystalline surface of a limited area by a small-volume catalytic liquid at the end of a growing nanowires (NW) characterized by a contact angle β, which contributes to a fundamental understanding of the nature of the contact angle of catalyst drops at the top of the NW. It is shown that under the conditions of stationary growth of NWs with a transverse singular face, there are only values of the angles β and γ (the angle of inclination of the side surface of the crystal to this face), which correspond to the minimum increment of the free energy of the three-phase system αLVcosβ + αSL = αSVcosγ and determine the stability of the catalyst drop at the top of the NW. With the growth of cylindrical NWs, the conditions of indifferent equilibrium are realized at the drop wetting perimeter. A drop, due to the dissolution of a crystallizing substance or its separation from a liquid solution, can take an equilibrium shape with a contact angle β that does not satisfy the equilibrium contact angle condition θ in the Young equation. A concentric break (rib) at the NW tip should increase the observed wetting angle θ and lead to contact angle hysteresis. The restrictions imposed on the value of the contact angle of a stable catalyst drop at the top of the NW are determined. The catalyst drop will take an equilibrium shape if the hysteresis angle β is in the range θ < β ≤ θ' + γ (θ' is the wetting angle of the NW side walls). For the growth of semiconductor NWs in the form of a straight cylinder, γ = 90° and therefore always β > 90°. It is shown that the direction of displacement of the three-phase line relative to the droplet surface is determined by the growth angle φ0: for the nonwetting growth mode of NWs (with a transverse face) φ0 = β – γ; for the wetting growth mode (with the end surface curved near the three-phase line)

RECLAIMING MODERATE ISLAM IN NAHDLATUL ULAMA: Challenging the Dominant Religious Authority in Digital Platform

This article examines Nahdlatul Ulama’s attempts to face three challenges, its internal dynamic within the elite religious circle, the influence of its leadership at the grassroots level, and the rise of the new religious authorities who employ social media to enlarge their influence. Amidst the growth of internet users bridging the gap between rural and urban areas, this rise of new religious authority has steeply eroded NU's domination, which bases Islamic traditionalism in rural areas. This article contends that NU cannot be viewed as a singular face of religious orientation. However, in the level of ideology, NU’s aswaja (ahl as-sunnah wa al-jama >’ah) brings its followers into a moderate view. This religious orientation has been contested respectively amidst organizational structure and different geographical landscapes of NU's people. Meanwhile, the dominance of Islamic conservative groups in the digital platform appears to be quite strong. Because of these challenges, NU struggles to reclaim its religious authority at the level of the youngest circles.

On possible new methods for δ-layer synthesis of the diamond transistor

An upper estimate of the activation barrier Ea, overcome by boron atom during its adsorption on singular face of unalloyed diamond, has been obtained using quantum chemistry methods. This process is connected with the formation of boron-doped δ-layer in the unalloyed diamond, which is an integral part of the diamond transistor. The estimate of Ea was found to be approximately 6–7 eV. It is correspondent by the order of magnitude with floating electrode potential drop relative to stationary low-temperature plasma at electronic temperature above ~ 1 eV. Meanwhile, in the existing high-frequency plasma-enhanced CVD (MWCVD) technology used to create boron-doped δ-layers, the source of the δ-layer growth is high-energy boron ions with energies of hundreds of eV (and even units of keV) which enter the substrate from MW plasma. This energy that the ions acquire at the near-electrode voltage drop is clearly excessive and leads both to excessively high depth of ion penetration into the diamond and to large dispersion of this depth. This reduces the quality of the δ-layer and the transistor efficiency as a whole. At the same time, specificity of high-frequency plasma, created in the MW-resonator for the diamond growth, allows plasma modes and diamond growth both with large (units of keV) and small (units of eV) near-electrode voltage drops. This paper considers the possibility of switching between these two modes. The high-drop mode realizes the rapid growth of unalloyed diamond and the low-drop mode – high quality δ-layer.

Potential of Morphology Repair: Experimental Research on the Regeneration of Incomplete Crystallographic KH2PO4 Crystal Enclosed by Singular Face (Crystal Research and Technology 8/2019)

Crystal Research and TechnologyVolume 54, Issue 8 1970024 Cover PictureFree Access Potential of Morphology Repair: Experimental Research on the Regeneration of Incomplete Crystallographic KH2PO4 Crystal Enclosed by Singular Face (Crystal Research and Technology 8/2019) First published: 12 August 2019 https://doi.org/10.1002/crat.201970024AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract Mingwei Li and co-workers (article no. 1800240) have examined the regeneration characteristics of incomplete crystals of crystallographic potassium dihydrogen phosphate (KH2PO4) in supersaturated solution. The designed crystals were enclosed by singular faces and thus provided surface conditions for ordinary layer-by-layer growth, however, thin surface layers grew from crystal edges or concave angles to repair the crystals to convex polyhedrons. It is assumed that the incomplete crystal possesses a "potential of morphology repair", which drives the thin surface layer growth. Volume54, Issue8August 20191970024 RelatedInformation

Experimental Research on the Regeneration of Incomplete Crystallographic KH2PO4 Crystal Enclosed by Singular Face

AbstractThe phenomenon of thin surface layer growth during the regeneration of incomplete crystallographic potassium dihydrogen phosphate crystal has not been thoroughly elucidated to date. In the present study, four sets of incomplete crystallographic KH2PO4 crystals enclosed by singular faces are designed to observe their regeneration characteristics in supersaturated solution. In all the crystals, even though every crystal face is singular surface, thin surface layers still grow from crystal edges or concave angles to repair themselves to convex polyhedrons. Through surface energy calculation, it is found that the thin surface layer growth encounters higher growth barrier than ordinary layer‐by‐layer growth. Here, an assumption is proposed that the incomplete crystal possesses a “potential of morphology repair”, which drives the thin surface layers growing to repair itself into complete form. This assumption is confirmed to some extent by a thin surface layer fragments experiment. The experiment implies that thin surface layer is the same as the ordinary crystal seed once separated from incomplete crystal, and its growth rate is one order slower than in incomplete crystal.

The Growth of InAsxSb1 –x Solid Solutions on Misoriented GaAs(001) Substrates by Molecular-Beam Epitaxy

The effect of a substrate misorientation degree from a singular face on the composition and morphology of layers of InAsxSb1 –x solid solutions obtained by molecular-beam epitaxy on a GaAs surface has been investigated. The substrates of GaAs wafers with the orientation (100) misoriented in the direction [110] by 0°, 1°, 2°, and 5° are used. The heterostructures are grown at temperatures of 310°C and 380°C (respectively, the lower and upper boundaries of the temperature range in which structurally perfect InAsxSb1 –x films form). The effect of the molecular form of arsenic (As2 or As4) on the composition of the layers is studied. The composition and structural properties are investigated using high-resolution X-ray diffractometry (HRXRD) and atomic-force microscopy (AFM). It is established that, in the series of misorientation angles 0° → 5°, the arsenic fraction x increases consecutively when using fluxes of both As2 and As4 molecules. With the As2 molecular flux, the fraction x increases only a little (1.05 times) with increasing degree of misorientation, while, when using the As4 flux, the increase in x is 1.75 times. An increase in the growth temperature leads to growth in the arsenic fraction in the solid solution. The surface morphology improves with an increasing degree of misorientation at a low growth temperature and degrades at a high temperature.

Application of Scale of Absolute Surface Potentials to the Reactions of Chemisorption and Electrocatalysis on Metals. Part 2

The concepts of the absolute surface potential (ASP) ES of the (hkl) facet of a metal crystal with ES = ΔGs/zF directly related to the Gibbs surface energy ΔGS and with an equilibrium between (auto) adsorption of its own atoms on this facet of Nad and negative charged surface vacancies (NCSV). On this basis, the ASP scale is a scale of adsorption potentials with point defects—the NCSV and adatoms, which determine their surface statistics as a result of the action of surface and electrostatic forces on these quasiparticles. This dualism is aimed at overcoming differences in the understanding of the surface potential in Helmgholz theory and Gibbs theory. The adsorption scale of the singular metal face has a special point—the potential of the zero charge (PZC) of the electrode $$E_{{\text{N}}}^{0}{\text{ = }}-\Delta G_{{\text{S}}}^{0}{{(hkl)} \mathord{\left/ {\vphantom {{(hkl)} {zF}}} \right. \kern-0em} {zF}}$$ with a minimum of adsorption of atoms and NCSV. Point of absolute adsorption devides the scale of cathodic and anodic polarization (Fig. 4.1, Part 1) with predominant adsorption of NCSV or adatoms, reaching the maximum degree at the potential of the second special point $$E_{{\text{S}}}^{0}$$ in each area of the ideal electrode polarization. Part 2 discusses the transition from the ASP to hydrogen scale using the ratio between the standard and absolute values ​​of a hydrogen electrode adopted by the International Union of Physical and Applied Chemistry. Combining the ASP scale with the scale of the absolute potentials of electrode reactions made it possible to calculate the electrode potential of a chemisorption and electrocatalytic reaction of hydrogen evolution on various metals, as well as the potential for the formation of passivating oxide on metals (Ni, Cr), known as the “Flade potential.”

Mechanisms of epitaxial growth of SiC films by the method of atom substitution on the surfaces (100) and (111) of Si single crystals and on surfaces of Si films grown on single crystals Al2O3

The structure and morphology of silicon carbide (SiC) films formed by a new method of atom substitution on the surfaces (100) and (111) of silicon substrates (Si) were investigated. It is shown that the singular faces (100) of Si in the process of substitution of silicon atoms for carbon atoms are transformed into a face of SiC, consisting of an ensemble of facets resembling saw-tooth structures, the side surfaces of which are covered with planes (111) and (110) and (210). Theoretically, a fundamentally different mechanism of atom substitution on the faces (111) and faces (100) is described and experimentally confirmed. It was found that on the vicinal surface of Si, deviated 4° or more from the singular face (100), during the synthesis of SiC, an ordered phase of SiC is formed, the surface morphology of which appears as of facets (scales) consisting of faces (111). It is shown that the method of topochemical substitution of atoms can grow epitaxial SiC layers not only on a silicon substrate, but also on substrates of other materials, in particular, on single-crystal sapphire substrates.

Kinetics of Structural Changes on GaSb(001) Singular and Vicinal Surfaces During the UHV Annealing

The dynamics of processes of antimony desorption was investigated on the singular and vicinal GaSb(001) surface by RHEED method. The role of the terraces edges was determined during antimony evaporation in Langmuir desorption mode. It is shown that the structural transition (2x5) -> (1x3) is a complex of two transitions - order -> disorder and disorder -> order. The influence of the degree of surface miscut from the singular face on the dimension of the transition (2x5) -> DO was studied. The activation energies of structural transitions ex(2x5) -> (2x5), (2x5) -> DO and DO -> (1x3) on singular and vicinal faces GaSb(001) were determined.

Kinetics of structural changes on GaSb(001) singular and vicinal surfaces during the UHV annealing

AbstractThe dynamics of processes of antimony desorption was investigated on the singular and vicinal GaSb(001) surface by RHEED method. The role of the terraces edges was determined during antimony evaporation in Langmuir desorption mode. It is shown that the structural transition (2 × 5) → (1 × 3) is a complex of two transitions— order → disorder and disorder → order. The influence of the degree of surface miscut from the singular face on the dimension of the transition (2 × 5) → DO was studied. The activation energies of structural transitions ex (2 × 5) → (2 × 5), (2 × 5) → DO and DO → (1 × 3) on singular and vicinal faces GaSb(001) were determined.

Irreversible order-disorder transformation of Ge(0 0 1) probed by scanning tunnelling microscopy

We investigate the surface structure of Ge(0 0 1) during the (2 × 1)–(1 × 1) phase transition occurring at T > 1130 K by high-resolution scanning tunnelling microscopy. We find a drastic size reduction of dimerized domains in line with substantial dimer breakup accompanied by surface roughening. Completing the picture provided by previous spectroscopic observations, probing with high spatial resolution reveals the nucleation of several nanodomains with distinct vicinal orientations and reconstructions. The structural transformation is irreversible and is not observed for other singular faces of Ge.

Seeing is Believing: Archival Imagery and Counter-Narratives

One by one, they emerge from the local archives. Singular black and brown faces, mixed among the seas of whiteness in class photographs, yearbook entries, black-owned newspapers, personal diaries, and more. Local historians had warned that these stories could not be found. And yet, there we were. One by one, two by two, church group by community picnic. The irony and tensions of being conspicuously unseen defines part of the black diasporic experience. This article employs archival photographs to construct a historical counter-narrative about the experiences of black communities in upstate New York. Using Ithaca, New York as a case study, I situate a “local” experience within African diaspora history.

Surface micromorphology of germanium single-crystal boules grown from melt

The morphology of the growth surface of germanium single crystals grown by directed crystallization and the Czochralski method is studied by interference profilometry, optical microscopy, and scanning electron microscopy (SEM). Stable periodic profile distributions on different time scales (~3 and ~0.3 s) indicating changes in the crystallization kinetics are revealed on the upper surface of disks grown by directed crystallization and the lateral cylindrical surface of Czochralski-pulled boules. Based on known data on temperature fluctuations at the crystal-melt interface and the parameters of the crystal’s surface profile and growth rates measured in this study, the kinetic coefficients are estimated to be βK = (2 × 10−6−7 × 10−7) m s−1 K−1. The two-dimensional pattern of irregularity distribution on the surfaces indicates the stepwise growth of the {111} singular faces according to the layer-by-layer mechanism. A correlation between profile irregularities and periodicity in the distribution of dislocation etch pits over the radius and lateral crystal surface is revealed on juvenile crystal surfaces.

The desiring-image: Gilles Deleuze and contemporary queer cinema

TABLE OF CONTENTS Acknowledgments List of Abbreviations Introduction The Triple Womb Queering the Cinema Books New Queer Is... New Queer Ain't Seven Pillars of Schizo Homo Pomo Word on Orientation, or Around 1991 Preview of Coming Attractions Chapter 1: Beyond Gay: Dead Ringers and Queer Perceptions We're Just Not Sure What Kind It Dissenting from A Dissenting View Mutant Textuality Perceptions of Perception: Movement, Time, Subtraction Perceptions and Desire: Types of Flows Out-of-Fields and the Desiring-Image The Desiring-Images of Dead Ringers First Out-of-Field: The Mantles vs. the World Second Out-of-Field: The Love that Keeps Almost Speaking Its Name Third Out-of-Field: The Triple-Womb and the Either... Or... Fourth Out-of-Field: Impulse and Immanence The Desiring-Image as Relation-Image Chapter 2: Hard Bodies and Sex Blobs: Deterritorializing Desire in Naked Lunch and Shortbus Innaresting Sex Arrangements Peaks, Sheets, and Series Everything Is Permitted: Incompossibilities of Desire Schizos and Counterpublics If on a Summer's Night a Sex-Blob Sounds, Stutters, and Scatterplots Kafka High, or a New Low?: Quandaries of the Minor Shortbus: The Queer Politics of Actual Sex Does This Bus Only Make One Stop? Chapter 3: Something in Her Face: Queering the Affection-Image in The Watermelon Woman Who Is She, and What Is She to You? The Riddle of the Lesbian Affection-Image Like Clockwork, or How to Make a Face Facing Elsie, and the Mystery of the Other Person Black Lesbians and Their Others Peaks of Present, or What Ever Happened to Lesbian Community? Sheets of Past and Centers of Indetermination Singular Face, Implying Multitudes Deflective Unities and Oracular Chores Faces in the Crowd Facing Forward Chapter 4: Brother to Brother and Adventures in Queer Crystallography Queer Crystallography Crystals, Then and Now The Four Types Looking for Bruce / Looking for Perry Through a Crystal-Image, Darkly What's Sex Got to Do with It? Chapter 5: Crystal-Queer Economies: Beau travail What's Money Got to Do with It? The Oyster and the Book in Blood The Broken Compass and the Three Economies Beau travail, or the Ambiguities Compound Crystals Bachelors and Belles transitions Chapter 6: Theses on a Philosophy of Queer History: Velvet Goldmine Changing the World / Changing Ourselves Angels, Aliens, and Orphans Point to Point B Wild Cards and Unexpected Critiques Toward Productive Ends The Minors and the Miners Conclusion The Pin and the Pearl Glossary Works Cited

Initial stage of the epitaxial assembly of graphene from silicon carbide and its simulation by semiemprical quantum chemical methods: Carbon face

The epitaxial growth of graphene on a singular carbon face of silicon carbide is simulated by semiempirical quantum chemical methods. It is shown that the main regularities of the growth of graphene on such a face, i.e., the sequence of surface reconstructions with a short spatial period (2 × 2) → (3 × 3) → graphene, are exhibited naturally during the analysis of various paths of graphene assembly and seeking the most probable path.

Orientational phase diagram of the epitaxially strained Si(001): Evidence of a singular (105) face

By exploiting the misfit strain of Ge on Si epitaxy, we examine the significant changes induced by surface stress in the polar structural phase diagram of Si(001) surfaces. Under compressive strain, the atomic and mesoscale structures of the vicinal Si(001) surfaces are converted into a new singular (105) face which does not exist on the strain-free equilibrium shape of Si and Ge. The observed structural modifications of substrates have far-reaching implications for the Stranski-Krastanov evolutionary path of three-dimensional islanding.

Hybrid Boundary Element Method for Two-Dimensional Linear Elastic Fracture Analysis

A robust one-step hybrid boundary element method for use in two-dimensional linearly elastic fracture mechanics analyses was developed and validated using well known analytic and numerical solutions. The direct boundary element and distributed dislocation methods were used to simulate non-degenerate domain boundaries and internal cracks, respectively. Using Gauss-Chebychev quadrature to evaluate the singular crack face integrals, very accurate mixed mode stress intensity factors for through slit cracks in multiply connected domains were obtained. The hybrid boundary element technique may facilitate damage tolerance design/analysis of complex structures, where the mechanisms of load transfer and progressive structural failure are key concerns.

An Autoethnography of a Face

Deleuze and Guattari (1987) suggest that one is a hacceity, an individuation that is not an individual, and a Body without Organs (BwO), multiplicities on a plane of immanence. Hacceities and BwOs flow unimpeded. Without direction they continually change. But on earth, hacceities and BwOs often fold into a singular face as they submit to a machine of faciality, an abstract system that totally integrates signification and subjectification. In this poststructural autoethnography, the author plays with these ideas. Following flows and coagulations, the author uses prose, theory, and drawing to bring to the fore faces and bodies of herself.

Formation of ultrathin iron magnetic films on the silicon vicinal surface

The phase composition, electronic structure, and magnetic properties of ultrathin layers of iron and iron silicides formed upon deposition of 1- to 25-A-thick Fe film on an atomically clean vicinal surface Si(100) at room temperature have been investigated using high-resolution photoelectron spectroscopy with synchrotron radiation and the magnetic linear dichroism in Fe 3p electron photoemission. It has been demonstrated that the phases involved (Fe-Si solid solution, the Fe3Si silicide, the iron film) are formed in the same order as in iron deposition on the Si(100) singular face; in this particular case, the segregation of silicon on the iron film is noticeably enhanced. It has been established that the ferromagnetic ordering of the films in the plane of the sample surface follows a threshold character and sets in after a 7-A-thick film has been deposited during the stage of growth of the Fe3Si silicide. A further deposition brings about an increase in the remanent magnetization of the film, which reaches saturation at coverages of about 20 — ricated exhibits magnetic anisotropy with the easy magnetization axis aligned with the substrate steps.