Perpendicular Surface Research Articles

Application of orientation imaging to the study of substructural development in cold deformed Al-0.3%Mn single crystal of {110} orientation

A systematic study of the deformation microstructures over 3 perpendicular surfaces was carried out in the present work in order to correlate better the substructure with slip patterns, initial and final crystal orientation, and the macroscopic coordinate system. The microstructure and texture evolution of high purity Al-0.3 wt% Mn alloy of initial near brass {110}<112> (or Bs) orientation, channel-die compressed to the strain level of 1.5, were studied by TEM (including TEM orientation mapping) and high-resolution FEG-SEM/EBSD techniques to observe crystal subdivision deformation patterns at the microscopic scale. The grain orientation dependent structures were analyzed in terms of active slip systems focussing on the crystallography of extended planar boundaries. It was concluded that the type of dislocation structure (one or two sets of microbands) in {110}<112> oriented crystallites, at moderate strains (< 1.5) depended strongly on the crystallographic grain orientation. In this non-ideal initial crystal orientation the applied deformation mode activates a double slip, of which one system predominates and leads to further rotation away from Bs. A general rotation combined with a wide orientation spread is observed after a strain up to 1.5. The microband boundary alignment corresponds very well to the traces of crystallographic {111} planes, on which most of the slip occurs.

Calculation Methods to Determine Crystallographic Elements: Interface Plane, Surfaces Plane and Twinning Elements, Based on Electron Diffraction Orientation Measurements by SEM and TEM

In the present work, we summarize three calculation methods to determine some specific crystallographic elements based on electron diffraction orientation measurements by SEM and TEM. The first one is to determine the plane indices of the faceted interfaces where the orientation relation¬ships (ORs) between the adjacent crystals are reproducible. To acquire the orientation data, we need to prepare only one sample surface but not two perpendicular sample surfaces as usually required in the standard double trace method. The second is to characterize the surface crystalline planes and directions of a faceted nano-particle under TEM imaging and diffraction mode. With the determination of the edge trace vectors and then the plane normal vectors in the screen coordinate system of TEM, their Miller indices in the crystal coordinate system can be calculated through coordinate trans¬formation. The third method is to determine the twin type and the twinning elements based on the orientation information acquired by SEM EBSD measurements from the two twinned crystals through misorientation calculations. These methods will facilitate related studies.

Nearby boundaries create eddies near microscopic filter feeders

We show through calculations, simulations and experiments that the eddies often observed near sessile filter feeders are frequently due to the presence of nearby boundaries. We model the common filter feeder Vorticella, which is approximately 50 microm across and which feeds by removing bacteria from ocean or pond water that it draws towards itself. We use both an analytical stokeslet model and a Brinkman flow approximation that exploits the narrow-gap geometry to predict the size of the eddy caused by two parallel no-slip boundaries that represent the slides between which experimental observations are often made. We also use three-dimensional finite-element simulations to fully solve for the flow around a model Vorticella and analyse the influence of multiple nearby boundaries. Additionally, we track particles around live feeding Vorticella in order to determine the experimental flow field. Our models are in good agreement both with each other and with experiments. We also provide approximate equations to predict the experimental eddy sizes owing to boundaries both for the case of a filter feeder between two slides and for the case of a filter feeder attached to a perpendicular surface between two slides.

Low-cost interference lithography

The authors report demonstration of a low-cost (∼1000 USD) interference lithography system based on a Lloyd’s mirror interferometer that is capable of ∼300nm pitch patterning. The components include only a 405nm GaN diode-laser module, a machinist’s block, a chrome-coated silicon mirror, substrate, and double-sided carbon scanning electron microscopy (SEM) tape. The laser and the machinist’s block were assembled in a linear configuration, and to complete the system, the mirror and substrate were taped to perpendicular surfaces of the machinist’s block. Approximately 50 silicon substrates were prepared, exposed, and developed, after which some were inspected in a SEM. The associated laser spectrum was also measured, enabling calculation of the laser’s fringe visibility as it varied along the substrate surface. To compare the exposed resist pattern to the fringe visibility, the authors measured the first order diffraction efficiency as a function of position along the grating surface. Their measurements indicated that artifacts seen in both the optical spectrum and resulting grating patterns arose from the laser diode source, thus improving the source characteristics will be the topic of future work.

Perpendicular surface magnetic anisotropy in an amorphous ferromagnet induced by adsorption occurring through the mechanism of the formation of hydrogen bonds

It has been found that the domain structures of amorphous magnetically soft iron-based ferromagnetic ribbons in an atmosphere of water vapor and methyl alcohol are significantly different. In the former case, several domains separated by domain walls oriented at an angle of 30°–40° to the long side of the sample are observed. In the latter case, two domains separated by one wall located in the middle of the sample in parallel to its long side are observed. In the former case, the normal component of the magnetization on the sample surface has been detected using the polar magnetooptical Kerr effect. In the latter case, the normal component of the magnetization is almost absent. The observed effects are reversible. The normal component of the magnetization is induced by the desorption of water and methyl alcohol molecules, which are absorbed through the mechanism of the formation of hydrogen bonds, from the sample surface. According to the performed estimate, the effective field of the perpendicular magnetic anisotropy reaches a value of 1.6 kA/m.

Quantifying Corrosion Growths on Perpendicular Magnetic Recording Media

High media roughness associated with perpendicular recording introduces the phenomenon of widely separated single needle-like corrosion growths after temperature-humidity stress. Previous generation longitudinal recording media demonstrated clusters of corrosion growths around a central media defect, which were detectable by reflected light. However, because of the isolated nature of this new type of corrosion, traditional ellipsometry is no longer effective. As a result, we have developed a method for quantifying scattered isolated corrosion growths on perpendicular recording media disk surfaces, using existing optical surface technology. Our method can detect corrosion densities down to 5000 corrosion sites/mm2, given corrosion size at least 0.3 mum in length and 7 nm in height. The amount of corrosion reveals itself as an increase in laser light scatter across a disk surface referenced to its original prestress scatter. Scanning electron microscopy and atomic force microscopy analysis of the corrosion growths verified that the scatter measurements correlate to physical properties such as density and size of corrosion needles.

The shape of extrusions and intrusions and initiation of stage I fatigue cracks

Scanning electron microscopy (SEM) combined with local milling by focused ion beam (FIB) was used to study the true shape of the relief developed on the surface of polycrystalline 316L steel cycled with constant plastic strain amplitude. Localization of the cyclic strain to persistent slip bands results in early formation of persistent slip markings. The evolution of the early relief formation is reported using the observation on two perpendicular surfaces. The observed configurations of extrusions and intrusions are discussed and compared with predictions of the latest models of fatigue crack initiation. The prominent role of intrusions in fatigue crack initiation is emphasized.

Anisotropy of the Exciton Processes in GaSe Crystals with Low S and Te Concentrations

The anisotropy of the excitonical processes in the GaSe crystals and GaSe with small quantities of GaS(GaSe 0.99 S 0.01 ) crystals has been studied through the optical specters (SO) and through the photoluminescence (PL) from the perpendicular surface on the symmetry axis C 6 (→E⊥→C polarization) and from the flat surface parallel with the C 6 axis (→E∥→C and →E⊥→C polarization). The edge of the fundamental band of the GaSe crystals as well as of the GaSe 0.99 S 0.01 and GaSe 0.99 Te 0.01 crystals is formed at T = 78 K of the direct excitons' band. The width of the free excitons' band is determined by the processes of interaction between the excitons and optical and acoustic phonons. Phonons with energy of 17 meV and 27 meV participate to the formation of the edge towards small energies of the excitonic band in the GaSe crystals. The average energy of the phonons that participate to the formation of the excitonic absorbtion band in the GaSe crystals with small concentrations of S and Te equals 17 meV. Due to the mechanism of interaction of the excitons and phonons the integral absorption coefficient for the studied crystals (polarized E→⊥→C) is in small increase once with the temperature whilst the integral absorption coefficient in the maximum of the direct excitons' band. The (n = 1) state is in diminution. For example, for the GaSe 0.99 Te 0.01 crystals, α increases from 2700 at T = 78 K to 2025 cm -1 at 220 K. The edge towards small energies of the free excitons' band in the GaSe crystals and GaSe crystals with small quantities of S and Te is in a great concordance with Toyozowa's theory. The constant of interaction between the free excitons with phonons with an average energy of 135 cm -1 equals 0.9. Using the spectral characteristic of the reflection coefficient from the surface parallel to the C 6 axis, there has been determined the refraction index placed in the center of the excitons n = 1 which equals 2.62 for GaSe and 2.58 and 2.55 respectively for the GaSe 0.99 S 0.01 and GaS 0.99 Te 0.01 crystals. The shifting of the reflection specters towards big energies like ∼10 meV in a E→⊥C→ polarization comparing to E→∥→C is determined by the difference of the oscillators' strength in these polarizations. The PL at T = 78 K specters from the surface parallel with the C 6 axis (polarized E→∥→C) confirm the difference between the forces of the excitons' oscillators in the E→∥→C and E→⊥→C polarization. The intensity of PL bands, at the (001) surface as well as at the (100) surface depends on the excitation intensity by a function of a I = L n force towards the emission bands of the direct and indirect free excitons the force factor is overlinear, and for the impurity nature bands it represents ∼0.5. The parameters that determine the width of the bands of excitonic PL is determined, considering the strong concentration of the structural faults at the (100) surface of the GaSe and GaSe 0.99 Te 0.01 and GaSe 0.99 S 0.01 GaSe crystals. Out of the spectral analysis I(L) the nature of the impurity bands has been determined, and from the PL specter structure there has been determined the energy of the accepting level which equals 93 meV from the maximum of the valence band of the GaSe crystals.

Microstrip line ferromagnetic resonance and Brillouin light scattering investigations of magnetic properties ofCo2MnGeHeusler thin films

${\text{Co}}_{2}\text{MnGe}$ films of different thicknesses (34, 55, and 83 nm) were grown by rf sputtering at $400\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$ on single-crystal ${\text{Al}}_{2}{\text{O}}_{3}$ corundum substrates showing an in-plane $\mathbf{c}$ axis. Their dynamic magnetic properties were studied using conventional and microstrip line (MS) ferromagnetic resonances (FMRs), as well as Brillouin light scattering (BLS) techniques. The effective magnetizations and gyromagnetic factors are first deduced from the resonance spectra involving the uniform magnetic mode under in-plane and out-of-plane magnetic applied fields. The angular dependence of the frequency, measured under a weak in-plane magnetic applied field, then allows deriving of the parameters describing the in-plane magnetic anisotropy. In the 34- and 55-nm-thick films, its behavior is described assuming a magnetic energy density showing an orthorhombic symmetry with a twofold axis normal to the film and planar anisotropy axes at $\ifmmode\pm\else\textpm\fi{}\ensuremath{\pi}/4$ of the $\mathbf{c}$ axis of the substrate; however, due to the comparative deduced values of the pertinent coefficients, this energy density is predominantly tetragonal. In the thickest film (83 nm), one of the planar anisotropy axes is parallel to $\mathbf{c}$ and approximate tetragonal symmetry is no more observed. Moreover, the orthorhombic symmetry is not completely fulfilled and a small misalignment between the principal directions connected to the uniaxial and the fourfold energy terms appears. Finally, the perpendicular surface standing modes, which are observed in MS-FMR and in BLS spectra, allow evaluation of the exchange stiffness constant. Good agreement between BLS and MS-FMR measurements has been found.

Microtopography Model of Rough Surface

For perfect surface roughness description is not enough to know characteristics of surface profile. It is necessary to use topography methods, so called microtopography. Thereby, surface roughness in microtopographycal understanding must be described with three coordinates, whose in Cartesian coordinates system compose point under consideration height h, abscissa and ordinate, determines point position in the plane. Most efficient methods in irregular surface roughness research are random function theory methods. Therefore, microtopography, analogically to profile, may consider as random function, but two dimensional function, i.e. two variable x and y random field h(x,y). From analogy with random process, random field can be normal – ordinates are distributed by normal (Gaussian) distribution. Moreover, random field can be homogeneous and heterogeneous. Random field is deemed homogeneous if its mean value is discretionary and correlation function depends only from distance between surface points. Important characteristic of random field is correlation function, whose depends of two variables t1 and t2 – orthogonal Cartesian coordinates of vector t. Random field is homogeneous and isotropic when its characteristics are equivalent in any direction. There are three types of surface anisotropy: • General event of surface anisotropy. Characteristics of this event roughness parameters are depend of surface split direction. • Surface roughness with direct anisotropy. Those surfaces are with typical traces of tool and they proper two mutually perpendicular surface roughness directions. • Extended anisotropy area – special event of anisotropy roughness. Of analytical opinion, gainfully anisotropy roughness see as extended occasional isotropy area. This let easy cross from anisotropy surface to isotropy and contrariwise, thereby embrace amount class of surface roughness. Let’s formulate microtopography model of rough surface [1]. Surface roughness is described with homogeneous normal random field h(x,y) that has uninterrupted correlation function and uninterrupted deriviates. We may consider that E{h(x,y)}=0. The mean random field value is plane called mean plane. For describing random field we must know mathematical expectation and field correlation function, what in fact reduces on determining dispersion and rationed correlation function r(t1, t2). Homogeneous random field dispersion D{h} doesn’t depends of direction and can be founded in any surface split. Given model of rough surface let inspect surfaces produced by abrasive instruments and friction surfaces after wear-in period.

An Experimental Study of the Effects of Surface Openings on Air Flow Caused by Wind in Courtyard Buildings

One of the modifications to increase the ventilation performance of buildings with courtyards is to create cavities to convey the air horizontally in the courtyard by the wind. This also decreases the cooling load, indirectly, in temperate or hot-humid climates. This study examines and attempts to explain the effects imposed by openings created in the architectural mass of courtyard buildings upon the velocities of airflows within such courtyards. The research was conducted through tests in a wind tunnel. The results from this study indicate that for buildings containing openings arranged in configurations different from those of courtyard buildings, openings located on perpendicular surfaces increase the velocities of airflows within courtyards in proportion to their dimensions and positions.

Reflective corner cube array

The present invention relates to vibration detection devices. In one embodiment a corner reflective array is provided. The corner reflective array includes at least one corner cube. Each corner cube includes three mutually perpendicular reflective surfaces that intersect in a corner.

Intensity-Dependent Optical Nonlinear Absorption and Refraction of Gold Nanorods

Au nanorods dispersed in aqueous solution were prepared with the electrochemical method. The absorption spectrum shows two absorption peaks corresponding to the perpendicular and transverse surface plasma resonance absorption of the nanorods. The third-order optical nonlinear properties are investigated by Z-scans. The signs of the nonlinear absorption coefficient and refractive index are reversed as the intensity of incident laser increases, which is due to the shape change of the gold nanoparticles melted by the intense laser pulses.

Indirect two-trace method to determine a faceted low-energy interface between two crystallographically correlated crystals

An indirect two-trace method to determine interfaces between two crystals with a uniquely defined interface plane is proposed. It involves preparation of only one sample surface, instead of the two perpendicular sample surfaces required by the traditional two-trace method. By making use of two independent interface trace vectors from one uniquely defined interface and the orientations of their adjacent crystals, the interface plane normal and thus the interface plane in the two correlated crystal systems can be determined through numerical calculations concerning coordinate system change. The new method is widely applicable to identify any uniquely defined and reproducible interfaces between crystallographically correlated crystals, even slip systems, provided that they are microscopically visible and crystallographically of the same nature. It can simplify the experimental procedure, increase the determination accuracy and broaden the scope of interface studies.

4 K , ultrahigh vacuum scanning tunneling microscope having two orthogonal tips with tunnel junctions as close as a few nanometers

An instrument that incorporates two scanning tunneling microscope (STM) tips which can have their tunnel junctions as close together as a few nanometers was designed and built. The sample is fixed and can be imaged simultaneously and independently with both STM tips. The tips and sample can be positioned and angled to image the same surface or perpendicular surfaces. The entire STM head is cooled with liquid helium to about 4K while in an ultrahigh vacuum environment. Macroscopic positioning of the tips is accomplished using piezoelectric “stick-slip” coarse motion stages, whereas atomic positioning is accomplished with piezoelectric tube scanners. This instrument addresses the critical need to locally characterize individual nanostructures and heterostructures.

Comparative evaluation of the electrical configurations for the two-dimensionalelectric potential method of damage monitoring in carbon fiber polymer–matrixcomposite

The effectiveness of the two-dimensional electric potential method of damage sensing in aquasi-isotropic carbon fiber polymer–matrix composite depends on the electricalconfiguration, i.e., the current direction relative to the surface fibers and theelectrical contact scheme. Oblique current application in any direction provideseffective damage sensing, as shown by using electrical contacts on the oppositein-plane surfaces. In-plane current application through the cross section in anydirection also provides effective damage sensing, as shown by using electricalcontacts that are either on the edge surfaces or in holes through the composite.In-plane surface current application is effective when the current is perpendicular tothe surface fibers (due to the low resistivity in the direction of the fibers) andis ineffective when the current is parallel to the surface fibers (due to the highresistivity in the direction perpendicular to the fibers). The oblique configuration isrecommended for practical implementation. In general, the potential method is reliablewhen (i) the resistance between the electric current line and the nearly parallelelectric potential gradient line is sufficiently low, as attained when these lines aresufficiently close, and (ii) the resistance between the current line and the damagelocation is sufficiently low, as attained when the distance of separation is sufficientlysmall.

신 워킹 전문화의 생체역학적 기능성 평가

This study was to analysis the kinematic and kinetic differences between new walking shoe(NWS : RYN) and general walking shoe(GWS). The subjects for this study were 10 male adults who had the walking pattern of rearfoot shrike with normal foot. The movement of one lower leg was measured using plantar pressure and Vicon Motion Analysis Program(6 MX13 and 2 MX40 cameras : 100 f / s) while the subjects walked at the velocity(1.5m/s. on 2m).. The results of this study was as follows : 1. The NWS was better than the GWS that caused injuries such as adduction, abduction and pronation are reduced While walking on a perpendicular surface, the landing angle and the knees angles were extensive which makes walking more safe which reduces anxiety and uneasiness. 2. The bottom of the NWS were now made into a more circular arch which supports the weight of the body and reduces the irregular angles when wearing GWS. This arch made the supporting area more wide which made the upholding the trunk of the body more effective. The whole bottom of the foot that supports the weight is more flexible in addition, increases the safeness of walking patterns and the momentum of the body. 3. The moment the heel of the foot of the NWS touch the ground, the range of the pressure were partially notable and the range of the pressure on the upper part of the thigh were dispersed The injuries that occurred while walking. primary factors when a shock related injuries are reduced Judgements of the impacts of the knees and the spinal column dispersing could be made.

Magnetic structure of vortex and antivortex states in patterned Co elements studied by using scanning ion microscopy with polarization analysis

Scanning ion microscopy with polarization analysis (SIMPA) is used to investigate the surface magnetic structure of patterned Co elements created in situ by focused ion-beam lithography from thin (30nm) Co films deposited on Si(100) substrates by electron-beam evaporation. The diameter d of the circular-shaped Co elements is varied between 5 and 38μm. Three-dimensional, spin- and spatially resolved SIMPA spin maps directly reveal the nonuniform micromagnetic structure of magnetic vortex and antivortex states. They are dominated by a circular or hyperbolic surface magnetization profile with a wide vortex or antivortex core in the center with a perpendicular surface magnetization component which decreases with increasing distance from the core. Varying d, the vortex wall thickness can be changed from 0.6 to 4.2μm. For Co elements with d&amp;lt;13μm, only single magnetic vortex states are found, whereas for d&amp;gt;13–15μm, magnetic multivortex and antivortex states are observed.

Ferromagnetic resonance study of polycrystalline cobalt ultrathin films

We present room-temperature ferromagnetic resonance (FMR) studies of polycrystalline ∥Pt∕10nmCu∕tCo∕10nmCu∕Pt∥ films as a function of Co layer thickness (1⩽t⩽10nm) grown by evaporation and magnetron sputtering. FMR was studied with a high-frequency broadband coplanar waveguide (up to 25 GHz) using a flip-chip method. The resonance field and the linewidth were measured as functions of the ferromagnetic layer thickness. The evaporated films exhibit a lower magnetization density (Ms=1131emu∕cm3) compared to the sputtered films (Ms=1333emu∕cm3), with practically equal perpendicular surface anisotropy (Ks≃−0.5erg∕cm2). For both series of films, a strong increase of the linewidth was observed for Co layer thickness below 3 nm. For films with a ferromagnetic layer thinner than 4 nm, the damping of the sputtered films is larger than that of the evaporated films. The dependence of the linewidth can be understood in terms of the spin-pumping effect, from which the interface spin-mixing conductance is deduced.

Adsorption of long flexible polymer chains at planar surfaces: scaling analysis and criticalexponents

The process of adsorption on a planar repulsive, ‘marginal’ and attractivewall of long flexible polymer chains with excluded volume interactions in theframework of the renormalization group field-theoretical approach, directly ind = 3 dimensions up to two-loop order, for the semi-infinite|ϕ|4 n-vector model in the limit n → 0 is investigated. We perform Padé and Padé–Borel resummation of the series obtained forthe surface critical exponents, characterizing the process of adsorption of long flexiblepolymer chains at the surface. The polymer linear dimensions parallel and perpendicular tothe surface and the corresponding partition functions, as well as the behaviour of themonomer density profiles and the fraction of adsorbed monomers at the surface and in theinterior, are studied. The field-theoretical results obtained at fixed dimensionsd = 3 are in good agreement with recent Monte Carlo calculations.