Structured illumination microscopy using micro-pixellated light-emitting diodes

Structured illumination is a flexible and economical method of obtaining optical sectioning in wide-field microscopy [1]. In this technique the illumination system is modified to project a single-spatial frequency grid pattern onto the sample [2, 3]. The pattern can only be resolved in the focal plane and by recording images for different transverse grid positions (or phases) an image of the in-focus parts of the object can be calculated. Light emitting diodes (LEDs) are becoming increasingly popular for lighting and illumination systems due to their low cost, small dimensions, low coherence, uniform illumination, high efficiency and long lifetime. These properties, together with recent developments in high brightness, ultraviolet operation and microstructured emitter design offer great potential for LEDs as light sources for microscopy. In this paper we demonstrate a novel structured illumination microscope using a blue micro-structured light emitting diode as the illumination source. The system is potentially very compact and has no-moving-parts

Partial Wave Analysis of J/ψ→γ(K+K−π+π−)J/\psi \to \gamma (K^+K^-\pi^+\pi^-)

BES data on $J/\psi \to \gamma (K^+K^-\pi^+\pi^-)$ are presented. The $K^*\bar K^*$ contribution peaks strongly near threshold. It is fitted with a broad $0^{-+}$ resonance with mass $M = 1800 \pm 100$ MeV, width $\Gamma = 500 \pm 200$ MeV. A broad $2^{++}$ resonance peaking at 2020 MeV is also required with width $\sim 500$ MeV. There is further evidence for a $2^{-+}$ component peaking at 2.55 GeV. The non-$K^*\bar K^*$ contribution is close to phase space; it peaks at 2.6 GeV and is very different from $K^{*}\bar{K^{*}}$.Comment: 15 pages, 6 figures, 1 table, Submitted to PL

Physical and mathematical modeling of inclusion removal with gas bottom-blowing in continuous casting tundish

Gas blowing at the bottom of tundish is an efficient metallurgy technique in clean steelmaking and has been widely concerned. In this paper, spherical alumina particles were selected to model inclusions, 1:3 scale model was utilized, the removal efficiency of inclusions with the gas bottomblowing in the tundish was studied by physical and mathematical modeling. The mathematical model is validated by comparing the predicted and measured residence time distributions and dye flow patterns of tracer. The results show that while the removal efficiency of large size particles has no obvious changes, the gas bottom-blowing has great contribution to the removal of small particles

Study on the Fabrication of Nano-SiC/Ni-P Composite Coatings with the Assistance of Electromagnetic-Ultrasonic Compound Field

Electroless nanocomposite platings were fabricated while the magnetic field strength and ultrasonic parameters were controlled. The effect of the complex field on the composite platings’ deposition process was discussed. The results show that composite coatings fabricated by a complex magnetic field had better density and homogeneity than coatings processed without the influence of external fields. The time-step deposition discussions indicate that the extra magnetic field accelerates the motion of the composite particulates in the bath through the action of the Lorentz force and promotes the nucleation and growth process of composite particulate clusters. The mechanical energy generated by the ultrasonic vibration activates the substrate surface and promotes the deposition of the Ni2+ in the plating solution on the substrate surface. While the complex field is functioning, ultrasonic and magnetic interactions play an important role in the fabrication of the uniform and dense nano-SiC/Ni-P composite coatings, which consist of amorphous spherical Ni-P/SiC particle clusters with 200 nm diameter. The nanoindentation hardness of these composite coatings was approximately 0.15 GPa

Individually-addressable flip-chip AllnGaN micropixelated light emitting diode arrays with high continuous and nanosecond output power

Micropixelated blue (470nm) and ultraviolet (370nm) AlInGaN light emitting diode arrays have been fabricated in flip-chip format with different pixel diameters (72μm and 30μm at, respectively, 100 and 278 pixels/mm2). Each micro-LED pixel can be individually-addressed and the devices possess a specially designed n-common contact incorporated to ensure uniform current injection and consequently uniform light emission across the array. The flip-chip micro-LEDs show, per pixel, high continuous output intensity of up to 0.55μW/μm2 (55W/cm2) at an injection current density of 10kA/cm2 and can sustain continuous injection current densities of up to 12kA/cm2 before breakdown. We also demonstrate that nanosecond pulsed output operation of these devices with per pixel onaxis average peak intensity up to 2.9μW/μm2 (corresponding to energy of 45pJ per 22ns optical pulse) can be achieved. We investigate the pertinent performance characteristics of these arrays for micro-projection applications, including the prospect of integrated optical pumping of organic semiconductor lasers