背光源导光结构仿真模型及其光学特性研究

本文研究了侧入式LED背光源导光结构的仿真及现实因素对背光源出光效果的影响。首先分析了导光结构的主要功能、特性以及相关理论基础;之后针对其出光特性提出一种简化而准确的仿真模型;最后结合生产实践,重点分析了LED光源与导光板的结构匹配,导光板薄形化处理,以及网点优化设计等关键因素变化对背光源出光效果的影响,并进行了实验验证。该研究对导光板的结构参数提出了合理的优化设计需求,对生产具有一定的实际指导意义。

Boosting photocatalytic hydrogen evolution enabled by SiO_(2)-supporting chiral covalent organic frameworks with parallel stacking sequence

Two-dimensional covalent organic frameworks(2D COFs)feature extendedπ-conjugation and ordered stacking sequence,showing great promise for high-performance photocatalysis.Periodic atomic frameworks of 2D COFs facilitate the in-plane photogenerated charge transfer,but the precise ordered alignment is limited due to the non-covalentπ-stacking of COF layers,accordingly hindering out-of-plane transfer kinetics.Herein,we address a chiral induction method to construct a parallelly superimposed stacking chiral COF ultrathin shell on the support of SiO_(2) microsphere.Compared to the achiral COF analogues,the chiral COF shell with the parallel AA-stacking structure is more conducive to enhance the built-in electric field and accumulates photogenerated electrons for the rapid migration,thereby affording superior photocatalytic performance in hydrogen evolution from water splitting.Taking the simplest ketoenamine-linked chiral COF as a shell of SiO_(2) particle,the resulting composite exhibits an impressive hydrogen evolution rate of 107.1 mmol g^(-1)h^(-1)along with the apparent quantum efficiency of 14.31% at 475 nm.Furthermore,the composite photocatalysts could be fabricated into a film device,displaying a remarkable photocatalytic performance of 178.0 mmol m^(-2)h^(-1)for hydrogen evolution.Our work underpins the surface engineering of organic photocatalysts and illustrates the significance of COF stacking structures in regulating electronic properties.

基于开关背光及工作指示灯亮度均匀性影响因素分析

从背光源本身发光性能、LED电路板的布置、LED散热结构、开关按键及工作指示灯导光结构、制造工艺等方面,重点分析对开关背光及工作指示灯亮度均匀性的影响,并提出有效的解决方案。通过实际应用和测试,在一定程度上提高并改善了开关背光及工作指示灯的亮度和均匀性。

Effect of KOH treatment on structural and photovoltaic properties of ZnO nanorod arrays

ZnO nanorod arrays （NRs） were synthesized on the fluorine-doped SnO2 transparent conductive glass （FTO） by a simple chemical bath deposition （CBD） method combined with alkali-etched method in potassium hydroxide （KOH） solution. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and current-voltage （I-V） curve were used to characterize the structure, morphologies and optoelectronic properties. The results demonstrated that ZnO NRs had wurtzite structures, the morphologies and photovoltaic properties of ZnO NRs were closely related to the concentration of KOH and etching time, well-aligned and uniformly distributed ZnO NRs were obtained after etching with 0.1 mol/L KOH for 1 h. ZnO NRs treated by KOH had been proved to have superior photovoltaic properties compared with high density ZnO NRs. When using ZnO NRs etched with 0.1 mol/L KOH for 1 h as the anode of solar cell, the conversion efficiency, short circuit current and open circuit voltage, compared with the unetched ZnO NRs, increased by 0.71%, 2.79 mA and 0.03 V, respectively.

OLED在汽车车灯上的应用

OLED英文为Organic Light-Emitting Diode,即有机发光二极管,1987年由华裔邓青云发明。从表面看,OLED就是在LED的基础上加了一个单词有机(Organic),但是与LED则完全不同。介绍了OLED的在车灯上的应用,OLED的优点,OLED的种类,在车灯上呈现的3D炫彩夺目的效果,OLED的未来的发展方向,OLED需要继续改进的方向,

Calculation of Valence Subband Structures for Strained Quantum-Wells by Plane Wave Expansion Method Within 6×6 Luttinger-Kohn Model

The valence subband energies and wave functions of a tensile strained quantum well are calculated by the plane wave expansion method within the 6×6 Luttinger Kohn model.The effect of the number and period of plane waves used for expansion on the stability of energy eigenvalues is examined.For practical calculation,it should choose the period large sufficiently to ensure the envelope functions vanish at the boundary and the number of plane waves large enough to ensure the energy eigenvalues keep unchanged within a prescribed range.

OLED技术在汽车车灯上的应用

科学技术随着人类进步在逐步发展,技术员们通过一点一滴积累,从无数次试验中攻坚克难,从最初的原始化的乙炔车灯,还是需要人工进行点亮的时代到现在市面上常见的卤素电灯泡,造型开始有了改革创新,脱离了原本的形式,甚至可以变成具有代表性标志性的Logo。OLED英文为Organic Light-Emitting Diode,从表面看,OLED就是在LED的基础上加了一个单词有机(Organic),但是与LED则完全不同。本文重点论述OLED技术发展背景及特点,提出OLED技术未来需要改进的方向。

Facile synthesis of UCNPs/Zn_xCd_(1-x)S nanocomposites excited by near-infrared light for photochemical reduction and removal of Cr(Ⅵ)

Photocatalysis driven by near-infrared（NIR）light is of scientific and technological interest for ex-ploiting solar energy.In this study,we demonstrate a facile hydrothermal process to synthesize core-shell nanoparticles combining upconversion nanoparticles（UCNPs）and alloyed ZnxCwhich can be excited using NIR or visible light.Morphologies,phase,and chemical composition have been investigated using field-emission scanning electron microscopy,transmission electron mi-croscopy,X-ray diffraction analysis,and atomic absorption spectroscopy.Moreover,we found that amorphous TiO2 layers existing in the final samples play an important role in formation ofyolk-shell nanoparticles,which bind the as-prepared ZnxCnanoparticlescan be tuna-ble by adjusting the amount of the Cd and Zn source compounds.The photochemical reduction of Cr（Ⅵ）in water has been performed to study the photocatalytic performance under irradiation by NIR light or a simulated solar light,showing efficient photoreduction and Cr（Ⅵ）removal over the/TiO2 yolk-shell nanoparticles.The as-prepared UCNPs@ZnxC/TiO2 nanoparticles show excellent production of hydroxyl radicals,which are responsible for the photochemical reduction of Cr（Ⅵ）to Cr（Ⅲ）.This study will provide an alternative strategy for en-vironmental wastewater treatment,making full use of solar energy.

Photocatalytic degradation of textile dyeing wastewater through microwave synthesized Zr-AC,Ni-AC and Zn-AC

The novel zirconium oxide, nickel oxide and zinc oxide nanoparticles supported activated carbons（Zr-AC, Ni-AC, Zn-AC） were successfully fabricated through microwave irradiation method. The synthesized nanoparticles were characterized using XRD, HR-SEM, XPS and BET. The optical properties of Zr-AC, Ni-AC and Zn-AC composites were investigated using UV–Vis diffuse reflectance spectroscopy. The photocatalytic efficiency was verified in the degradation of textile dyeing wastewater（TDW） in UV light irradiation. The chemical oxygen demand（COD） of TDW was observed at regular intervals to calculate the removal rate of COD. Zn-AC composites showed impressive photocatalytic enrichment, which can be ascribed to the enhanced absorbance in the UV light region, the effective adsorptive capacity to dye molecules, the assisted charge transfer and the inhibited recombination of electron-hole pairs. The maximum TDW degradation（82% COD removal） was achieved with Zn-AC. A possible synergy mechanism on the surface of Zn-AC was also designed. Zn-AC could be reused five times without exceptional loss of its activity.

Structure optimization of polymeric Mach-Zehnder rib waveguide

A systematic analysis of the polymeric Mach-Zehnder rib waveguide is presented based on the calculation and optimization. The simulation is carried out with the Effective Index Method (EIM) and two-dimensional (2-D) Finite Difference Beam Propagation Method (FD-BPM). The large refractive index step between the consecutive polymer layers is reduced by using EIM and thus the precision of the calculation is ensured. The important param- eters of the waveguide such as Y-junction angle and the separation gap are discussed and their relationships with the optical power propagation and the loss characteristics are investigated in this paper. The total loss of the opti- mized structure is 0.258 dB.

STUDY ON RECTANGULAR WAVEGUIDE GRATING SLOW-WAVE STRUCTURE WITH COSINE-SHAPED GROOVES

This paper focuses on a new rectangular waveguide grating Slow-Wave Structure (SWS) with cosine-shaped grooves and studies the propagation characteristics of the wave in the SWS. By using the approximate field-matching conditions,the dispersion equation and the coupling impedance of this circuit are obtained. The dispersion curves and coupling impedances of the fundamental wave are calculated and the influences of the various geometrical dimensions are discussed. The results show that the bandwidth of the cosine-shaped groove SWS is much wider than that of rectangular-shaped groove one. And reducing the groove width can broaden the frequency-band and decrease the phase-velocity,while increment of the groove-depth can also decrease phase-velocity. For above cases,the coupling impedance is more than 16Ω. The present analysis will be helpful on further study and design of the RF systems used in millimeter wave Traveling Wave Tube (TWT).

Fabrication of Alq_3/PBD OMQW Structures and Its Photoluminescence Characteristics

Abstract: Organic multiple quantum well(OMQ) structures consisting of alternating layers of tris(8 - quinolinolato)aluminum( ff) (Alq3) and 2 - (4 - biphenylyl) -5 - (4 - ter - butylphenyl) -(1,3,3- oxadiazole) (PBD) have been fabricated by organic molecular beam deposition (OMBD). The individual layer thickness in the multilayer samples was varied from 6 nm to 20 nm. The multiple quantum well structures were determined by low angle X - ray diffraction, optical absorption and photolumi-nescence(PL). The PL spectra narrow and the emission energy has been observed to shift to higher energy compared with that in the monolayer structure, suggesting a quantum size effect.

Structural insights of mechanically induced aluminum-doped hydroxyapatite nanoparticles by Rietveld refinement

Aluminum doped hydroxyapatite （HA：AI3 ＋） nanopowders were successfully prepared via a simple and efficient one-pot mechanochemical route. The effects of dopant loading on phase compositions and structural features were assessed by Rietveld analysis. The XRD-Rietveld refinement revealed the stabilization of HA in hexagonal structure for all the samples. The sharpness and intensity of the apatite-derived XRD peaks decreased as the dopant content increased to 10% due to the increase in lattice imperfections and mechanically induced amorphization. The incorpo- ration of A13 ＋ into the HA lattice decreased the unit cell parameters. From the FfiR measurements, the representing bands of apatite were identified in all cases. The mechanosynthesized nanopowders consisted of nanospheroids with an average size of 44 - 20 nm and therefore are promising for bone tissue regeneration.

Effect of Annealing Temperatures on the Structural and Electrical Properties of Laser Induced Plasma for TiO2x-1Bix Thin Films

In this study, Bismuth doped Titanium dioxide thin films were deposited on glass substrates by a pulse laser deposition using laser. The effect of annealing temperature on the structural and electrical properties was investigated. X-ray diffraction pattern for pure and doped titanium dioxide films with different doping different ratio with Bi show that these films have amorphous structure oanvert to polycrystalline structure with annealing and doping and have a good identically with standard peaks for Anatase and Rutile phases. The orientation was at specific direction for Rutile. The crystalline of films increases by the increase of doping ratio. The crystalline increased with annealing temperature. Annealed films at different annealing temperatures have been studied. The results show that these films have two activation energies and by increasing the doping ratio, the activation energies and the conductivity increase. Both the annealing and composition effects on Hall constant, density of electron carders and Hall mobility are studied. Hall Effect measurements show that all films have n- type charge conductivity and the concentration increases while the mobility decreases with doping and annealing.

Superconductivity at 10.4 K in a novel quasi-one-dimensional ternary molybdenum pnictide K2Mo3As3

Here we report the discovery of the first ternary molybdenum pnictide based superconductor K2Mo3As3. Polycrystalline samples were synthesized by the conventional solid state reaction method. X-ray diffrac- tion analysis reveals a quasi-one-dimensional hexagonal crystal structure with （Mo3As3）2 linear chains separated by K^＋ ions, similar as previously reported K2Cr3As3, with the space group of P-6m2 （No. 187） and the refined lattice parameters a = 10.145（5） A and c = 4.453（8） A. Electrical resistivity, magnetic susceptibility, and heat capacity measurements exhibit bulk superconductivity with the onset Tc at 10.4 K in K2Mo3As3 which is higher than the isostructural Cr-based superconductors. Being the same group VIB transition elements and with similar structural motifs, these Cr and Mo based superconductors may share some common underlying origins for the occurrence of superconductivity and need more investigations to uncover the electron pairing within a quasi-one-dimensional chain structure.

Bimodal plate structures induced by pulsed laser in duplex-phase Zr alloy

A duplex-phase Zr-2.5Nb alloy was treated by pulsed laser, followed by careful microstructural characterization using field emission gun scanning electron microscope and attached electron backscatter diffraction. Beneath the modification zones with common uniform α-plate structures(UPS), a layer of unreported bimodal α-plate structures(BPS) featured by coarse(submicron)plates forming multiple cores surrounded by dense fine(nanoscale) plates was found. Presence of such BPS is attributed to non-equilibrium thermodynamic conditions induced by the pulsed laser treatments. Limited diffusion of Nb due to the short pulse during laser heating allows β phases with distinctly different Nb contents to be presented: Nb-enriched prior β films and Nb-depleted β phases, transforming into the fine and the coarse plates during cooling, respectively. Orientation analyses show that both types of plates in the BPS are aroused essentially from a single β orientation, suggesting epitaxial growth of the Nb-depletedβ phases from the preexisting β films.

Spectral Absorption Gas Sensor Based on Anti-Resonant Reflecting Optical Waveguide

An air-silica microstructure optical fiber based on the anti-resonant reflecting optical waveguide （ARROW） principle was used to develop a spectral absorption gas sensor. The ARROW fiber has an air core and an air cladding layer. An ARROW fiber with a length of 725mm was used to construct a sensing system to detect acetylene gas. The gas was injected into the fiber from one end of the fiber. The transmission spectra were collected using an optical spectrum analyzer. The results indicate that the system can detect the gas of different concentrations and has the good system linearity. The response time of the system is about 200 s.

Experimental demonstration of the three-phase-shifted DFB semiconductor laser with buried heterostructure using common holographic exposure

In this article, we report the first experimental demonstration of the three-phase-shifted （3PS） DFB semiconductor laser with buried heterostructure based on the Reconstruction-Equivalent-Chirp （REC） technique. The simulation results show that the performances of the equivalent 3PS DFB semiconductor laser are nearly the same as those of the true 3PS laser. Compared with the quarter-wave-phase shift （QWS） DFB semiconductor laser, the 3PS DFB semiconductor laser shows better single-longitude-mode （SLM） property even at high injection current with high temperature. However, it only changes the ~un-level sampling structures but the seed grating is uniform using the REC tech- nique. Therefore, its fabrication cost is low.

Nanotube photovoltaic configuration for enhancement of carrier generation and collection

We report on the growth of geometric feature tuned semiconductor nanotubes on a transparent substrate through the application of an anodic aluminum oxide membrane-assisted method. Three-dimensional nanotube solar cells are developed in which semiconductor absorbers are not only used to fill the inner core of the nanotubes, but also to replace the membrane and to fill the intertube space between the nanotubes. The nanotube solar cells generate and separate carriers in three dimensions, namely, inside the cores of the nanotubes, in the intertube space between the nanotubes along the radial direction, and above the nanotubes along the axial direction. In preliminary experiments conducted to demonstrate the potential of this approach, nanotube CdS-CdTe solar cells were fabricated. CdS nanotubes with an inner diameter, wall thickness and intertube spacing of 35, 20, and 35 nm, respectively, were grown; the porosity and CdS nanotube density were 36.5% and 2.26 × 10^10 nanotubes/cm^2, respectively. These features of CdS nanotubes enable more efficient carrier collection because of the reduced recombination, especially in those cases in which the minority carrier lifetime is short, thus resulting in a diffusion length of less than 100 nm. Nanotube CdS-CdTe solar cells exhibit a wide and strong spectral response and quantum efficiency, indicating enhanced light absorption and carrier generation and collection. Without the benefit of an antireflection coating, the cells exhibited a wide and strong spectral response of quantum efficiency, and a short current density of 25.5 mA/cm^2, an open circuit voltage of 750 mV, and a power conversion efficiency of 10.7% under 1-sun illumination. The materials and electro-optical characterizations indicated well-defined junction and interface behavior in these 3D nanotube solar cell configurations.

Design, Fabrication, and Measurement of Two Silicon-Based Ultraviolet and Blue-Extended Photodiodes

Two silicon-based ultraviolet （UV） and blue-extended photodiodes are presented, which were fabricated for light detection in the ultraviolet/blue spectral range. Stripe-shaped and octagon-ring-shaped structures were designed to verify parameters of the UV-responsivity, UV-selectivity, breakdown voltage, and response time. The ultra-shallow lateral pn junction had been successfully realized in a standard 0.5-μm complementary metal oxide semiconductor （CMOS） process to enlarge the pn junction area, enhance the absorption of UV light, and improve the responsivity and quantum efficiency. The test results illustrated that the stripe-shaped structure has the lower breakdown voltage, higher UV-responsicity, and higher UV-selectivity. But the octagon-ring-shaped structure has the lower dark current. The response time of both structures was almost the same.