Hybrid MEMS optical scanner for volumetric 3‐D displays

Abstract— A fabrication technique and characteristics of high‐power‐handling microelectromechanical systems (MEMS) optical scanners for laser 3‐D volumetric‐image display application is reported. The MEMS scanner is designed to control the reflection of high‐power YAG‐laser beam by using the optomechanical combination of a dielectric‐film‐coated mirror cube and an electrostatic‐MEMS‐scanner platform. These hybrid‐type MEMS optical scanners have a stroke of about 20° at resonant frequencies of 600 Hz when a 45‐V pulse voltage is applied.     

Imaging-Based Metrics Drawn from Visual Perception of Haze and Clarity of Materials. I. Method,Analysis, and Distance-Dependent Transparency

A versatile imaging-based method is presented for quantifying the transparency of materials based on “illumination diffusion” (ID), representing scattering- and refraction-induced change in the spatial distribution of transmitted light intensity. Samples are backlit through a graticule mask, with analysis performed by comparative evaluation of graticule images recorded as-is and viewed through a sample, mimicking visual perception. ID-haze is quantified as the reduction of contrast, while ID-sharpness is derived from imaged knife-edge acuity. Measurements are performed for diverse materials, including clarified polyolefins, silica-filled amorphous polymers, semicrystalline films, and etched polymer sheets. Comparisons with the respective haze and clarity values obtained using a common ASTM D1003 haze-meter are made in terms of their quantitative correlation and suitability for applications. In particular, unlike conventional instruments, ID-based analysis captures the variation of transparency with sample-to-object “airgap” distance. Gratifyingly, ID-haze generally features a one-to-one correlation with standard ASTM haze, when determined at a specific distance. The presented method also enables sensitive detection of local defects—differentiating them from large-area characteristics—and accurately extracts the contribution of luminescence to loss of transparency. ID-based method therewith offers unique opportunities for application- and airgap-specific transparency analysis, and advanced options for optical process- and quality control.     

Dialkyl furan‐2,5‐dicarboxylates,epoxidized fatty acid esters and their mixtures as bio‐based plasticizers for poly(VInylchloride)

Dialkyl furan‐2,5‐dicarboxylates and epoxidized fatty acid esters (EFAE) of varying molecular weights and volatilities, as well as their mixtures, were investigated as alternative plasticizers for poly(vinylchloride) (PVC). The EFAE utilized were epoxidized soybean oil (ESO) and epoxidized fatty acid methyl ester (e‐FAME). All plasticizers were compatible with PVC, with plasticization efficiencies usually increasing with decreasing molecular weights of the plasticizers (except in the case of ESO, which was remarkably effective at plasticizing PVC, in spite of its relatively high molecular weight). In comparison with phthalate and trimellitate plasticizers, the alternatives generally yielded improved balance of flexibility and retention of mechanical properties after heat aging, with particularly outstanding results obtained using 30?50 wt % e‐FAME in mixtures with diisotridecyl 2,5‐furandicarboxylate. Although heat aging characteristics of the plasticized polymer were often related to plasticizer volatilities, e‐FAME performed better than bis(2‐ethylhexyl) 2,5‐furandicarboxylate, and bis(2‐ethylhexyl) phthalate of comparatively higher molecular weights. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42382.     

Investigation of chemical transformations of thiophenylglycoside of muramyl dipeptide on the fumed silica surface using TPD-MS,FTIR spectroscopy and ES IT MS

In this study, chemical transformations of benzyl ester of О-(phenyl-2-acetamido-2,3-dideoxy-1-thio-β-d-glucopyranoside-3-yl)-d-lactoyl-l-alanyl-d-isoglutamine (SPhMDPOBn) on the fumed silica surface were examined, and the surface complex structure was characterized by temperature-programmed desorption mass spectrometry (TPD-MS), infrared spectroscopy (FTIR) and electrospray ion trap mass spectrometry (ES IT MS). Stages of pyrolysis of SPhMDPOBn in pristine state and on the silica surface have been determined. Probably, hydrogen-bonded complex forms between silanol surface groups and the C = O group of the acetamide moiety NH-(CH₃)-C = O…H-O-Si≡. The thermal transformations of such hydrogen-bonded complex result in pyrolysis of SPhMDPOBn immobilized on the silica surface under TPD-MS conditions. The shifts ∆ν of amide I band (measured from 1,626 to 1,639 cm^−l for SPhMDPOBn in pristine state) of 33 and 35 cm^−l which occurred when SPhMDPOBn was immobilized on the silica surface may be caused by a weakening of the intramolecular hydrogen bonding of the SPhMDPOBn because the interaction with the silica surface as hydrogen bond with silanol groups is weaker than that in associates.     

On the ejection-induced instability in Navier-Stokes solutions of unsteady separation

Numerical solutions of the flow induced by a thick-core vortex have been obtained using the unsteady, two-dimensional Navier-Stokes equations. The presence of the vortex causes an adverse pressure gradient along the surface, which leads to unsteady separation. The calculations by Brinckman and Walker for a similar flow identify a possible instability, purported to be an inviscid Rayleigh instability, in the region where ejection of near-wall vorticity occurs during the unsteady separation process. In results for a range of Reynolds numbers in the present investigation, the oscillations are also found to occur. However, they can be eliminated with increased grid resolution. Despite this behaviour, the instability may be physical but requires a sufficient amplitude of disturbances to be realized.     

Nonlinear optical absorption of ZnO doped with copper nanoparticles in the picosecond and nanosecond pulse laser field

The nonlinear absorption of nanocomposite layers based on ZnO implanted with Cu+ ions with an energy of 160 keV in implantation doses of 10(16) and 10(17) ions/cm2 was investigated. The values of the nonlinear absorption coefficient were measured by the Z-scan method at a wavelength of 532 nm by use of nanosecond and picosecond laser pulses. Possible optical applications of these materials are discussed.     

Characteristics of a Sector of the Endcap Hadron Calorimeter for the CMS Facility

The characteristics of the prototype of the endcap hadron calorimeter for the CMS facility have been measured. Using the relations between the measured calorimeter response to a radiation source, muons, and pions, it is possible to determine the energy scale of the data-acquisition electronics, which will be used in future experiments along with the calorimeter. The light yield in the calorimeter due to a minimum-ionizing particle was measured. The effect of various factors on the duration of the calorimeter signal is analyzed. The joint operation of the hadron and electromagnetic calorimeters was investigated. The possibility of adjusting the uncompensated system using the data from a scintillation counter inserted between the calorimeters is analyzed. It is shown that the presence of a structural material between the calorimeters will not lead to a noticeable degradation in the energy resolution of the hadron calorimeter.     

Ultrasonic Assisted Fabrication of Nanocomposite Electrode Materials Au/C for Low-Voltage Electronics

Au/C nanocomposites have been obtained by the ultrasonic assisted reduction of HAuCl₄ solutions, impregnated in carbon material pores, using NaBH₄ as a reducing agent. It was established that conditions of nanocomposite (NC) synthesis exert an essential influence on the shape and size characteristics of Au filler and functional properties of NCs. Characterization of NCs by X-ray diffraction, small-angle X-ray scattering, and cyclic voltammetry methods has revealed that an increase in the NaBH₄ concentration raises not only gold nanoparticle dispersion in composites but also an electrochemical capacitance of Au/C NC electrode materials. A higher specific capacitance (700 F/g) for the NC electrode (NC-5 wt%-Au/C-1) was observed at a scanning rate of 10 mV/s in the potential window from (?1)V to (+1)V.