Angle-dependent Technique Research Articles

Programmable Nanoscale Crack Lithography for Multiscale PMMA Patterns.

Crack lithography is important for preparing microstructured materials. This strategic use of cracking breaks with the traditional idea that cracks are unwanted and has great potential for high-resolution and high-throughput production. However, the ability to control nanoscale crack patterning is still insufficient. Here, we present a nanoscale, programmable angle-dependent technique to control crack generation that relies on standard electron-beam lithography. Multiscale patterns of poly(methyl methacrylate) of arbitrary shape, geometric size, and large area were obtained, greatly expanding the processing capacity of electron-beam lithography. In addition, we observed the interaction between adjacent structures and cracks, which resulted in crack suppression or second-order cracks. We also demonstrated that angle-dependent nanoscale cracks can be used in physical unclonable functions and have great application prospects in the field of information security. We believe that our strategy for programmable nanoscale crack patterning provides new opportunities and perspectives for nanofabrication.

Engineered omnidirectional antireflection ITO nanorod films with super hydrophobic surface via glancing-angle ion-assisted electron-beam evaporation deposition

Growths of the indium tin oxide (ITO) nanorod films have been demonstrated by ion-assisted electron-beam evaporation with the glancing-angle deposition technique based on variation in deposition rate. Investigations have been performed on nanostructured ITO films deposited on ITO-coated commercial substrates in comparison to bare substrates. The physical microstructures have been investigated by grazing-incident X-ray diffraction (GIXRD), field-emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). The electrical, optical, and hydrophobic properties were characterized by four-point probe measurements, UV–Vis–NIR spectrophotometry with angle-dependent technique, and contact angle goniometry, respectively. The results indicated that physical morphologies and nanorod diameters of ITO nanorod films were heavily influenced, and thus could be controlled, by deposition rate. The primary reason was self-annealing effect which occurred during film deposition and was crucial factor towards surface diffusion and film crystallinity. From the optical examinations, ITO nanorods deposited on the ITO-coated glasses exhibited significant improvements on transparent conductive oxide (TCO) properties from reference samples. The proposed ITO materials could therefore function as omnidirectional anti-reflection materials and super hydrophobic surface. This work have also proved that the ITO nanorods prepared by the electron-beam evaporation with the GLAD technique was highly promising for solar cell and optoelectronic applications.

Mitral Annular Velocities Generated by Speckle Tracking Imaging: Reproducibility and Correlation with Tissue Doppler Velocities

Early diastolic mitral annular velocities (E') are routinely generated by tissue Doppler imaging (TDI), an angle-dependent technique. Velocity vector imaging (VVI) lacks this limitation. Normal VVI E' values and their correlation with TDI E' are unknown. E' by VVI and TDI were compared in 100 patients. VVI velocities are lower and correlate moderately with TDI velocities for medial E' (r = 0.405) and mildly for lateral E' (r = 0.278) and are image quality dependent. In patients with diastolic or systolic dysfunction, no correlation was found. E' < 0.06 m/s by VVI for the medial and lateral annulus can detect abnormal diastolic function with sensitivity of 90% and 77%, respectively, and with specificity of 56% and 52%, respectively. E' by VVI is lower than by TDI with a poor agreement between the measurements, which are therefore not interchangeable. Although VVI can be performed offline, this method is dependent on image quality.

Enhancement effect in photon-stimulated ion desorption for benzene adsorbed on silicon surfaces observed using angle-dependent technique

We have investigated photon-stimulated ion desorption from deuterated benzene (C 6D 6) adsorbed on Si(1 0 0) and Si(1 1 1) surfaces following C 1s core excitation. Using time-of-flight mass spectrometry combined with angle-dependent technique, we measured the dependences of mass-spectra of desorption ions on photon energies and on incident angle ( θ) of synchrotron beam. We have found the ion yields for adsorbate-derived fragments of CD + and CD 2 + are enhanced in very small angles of incident X-rays. Moreover, molecular orientation effect appeared in excitation energy dependences of D + ions from the Si(1 0 0) and Si(1 1 1) surfaces; that is, ion yield spectra measured at θ = 10° are different from that at θ = 65°. Furthermore, it was found that desorption ion yields increase greatly with decreasing incident angles. The angular dependences are consistently similar for all ion species, excitation energies, and indexes of substrates. Possible desorption processes are described on the basis of the observations.

Surface Characterization of Rosin Sizing Agents on Paper. Relationship between Surface Coverage Ratio of Rosin Sizing Agents on Pulp Fiber and the Liquid Absorption Characteristics.

The relationship between the surface coverage ratio of rosin sizing agents on pulp fiber and the liquid absorption characteristics was examined. The surface coverage ratio of rosin on paper sheets was estimated by the degree of surface carbon atom concentration, which was obtained from the ESCA angle-dependent technique. The Stöckigt sizing degree, the rate of change in contact angle with the elapse of time and the magnitude of slope of the line in dynamic contact angle were adopted as the liquid absorption characteristics.In the case of the emulsion type rosin, the liquid absorption characteristics changed notably by heat treatment in comparison to those in the soap type rosin.The Stöckigt sizing degree increased with the surface coverage ratio, and the rate of change in contact angle with elapse of time and the magnitude of slope to the line in dynamic contact angle decreased with the increase in the surface coverage ratio. Furthermore, the rate of change in contact angle and the magnitude of slope to the line in dynamic contact angle decreased remarkably by heat treatment.

Surface Characterization of Rosin Sizing Agent on Paper. Surface Coverage Ratio of Rosin Sizing Agents on Pulp Fiber.

Distribution of rosin size in handsheets, which were prepared from hardwood bleached kraft pulp added with either soap-type rosin size or emulsion-type rosin size, was studied using the following two methods: (A) back-scattering mode of scanning electron microscopy for handsheets pre-treated with OS04 in the gas phase, and (B) ESCA angle-dependent technique. Rosin size components were observed as contrasted area from back-scattered electron images. No clear difference in areas due to rosin size components was observed between the handsheets dried at 20°C and those heated at 170°C for 20sec., when the handsheets from L•BKP added with soap-type rosin were used as samples. In the case of handsheets prepared from L•BKP with emulsion-type rosin size, the areas due to size components decreased by heat treatment, suggesting that partial melting and spreading of the size components occurred on pulp fiber surfaces. On the other hand, when the ESCA angle-dependent technique was used, areas due to rosin size components clearly increased by the heat treatment at 170°C for 20sec. for the handsheets prepared with emulsion rosin size at any addition levels examined. The maximum coverage ratio of emulsion-type rosin size was calculated as about 48% on paper surface. The difference in coverage ratios obtained between the two methods may be ascribed to that in the detectable depth.

Surface characterization of a rosin sizing agent in paper by means of EPMA, ESCA and TOF-SIMS

Abstract EPMA(e1ectronprobe micro analysis), ESCA (electron spectroscopy for chemical analysis) and TOF-SIMS (time of flight type secondary ion mass spectrometry) were used to detect the distribution of a rosin sizing agent in paper. For EPMA we labelled paper samples with osmium tetroxide which enabled the detection of rosin in the XY direction of the paper sheet. For ESCA we labelled paper samples with fluorine which also enabled the detection of rosin. At the same time, the ESCA angle-dependent technique was used to obtain depth profiles of the rosin. Also, distribution images of rosin on an extremely thin ( 1 nm) surface layer were made observable by monitoring fragment ions from the rosin with TOF-SIMS. By using EPMA, a notable difference in rosin distribution was shown on the pulp fiber. However, according to the TOF-SIMS examination, the rosin was shown to be distributed relatively even in an extremely thin surface layer. The ESCA angle- dependent technique showed that rosin was present mainly on the outer surface layer.