An efficient luminescent bonding-type Eu-containing copolymer as a red-emitting phosphor for fabrication of LED

A luminescent europium-containing copolymer, poly(MMA-MA-co-Eu(TTA)₂phen), was synthesized though a reaction of EuCl₃, 1,10-phenanthroline (phen), α-thenoyltrifluoroacetone (TTA) with copolymer of maleic acid (MA) and methyl methacrylate (MMA). The copolymer was characterized by FT-IR, UV–vis, gel permeation chromatograph (GPC), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. The Eu-copolymer phosphor exhibited high thermal stability and excellent photoluminescence properties, appropriate CIE chromaticity coordinates for red and a quantum yield of 24% under near-UV light excitation. It emitted intense red light at 613 nm under UV excitation at room temperature, which is attributed to the ⁵D₀ → ⁷F₂ transition of Eu(III) ions. An intense red-emitting light-emitting diode (LED) was fabricated by combining poly(MA-MMA-co-Eu(TTA)₂phen) with a 395 nm-emitting InGaN chip. The results indicate that the Eu-copolymer phosphor may act as a red component for fabrication of white LEDs.     

预应力混凝土管桩两种施工方法的特点比较

预应力管桩有捶击沉桩和静压沉桩两种施工方法,其各自存在优缺点及适应性,对结构设计师和土建建造师正确了解其特性和正确选用施工方法具有重要意义。     

Experimental Study on a Hot‐Oxygen Burner in a Bench‐Scale Gasifier

The direct‐ignition technology of an entrained‐flow coal‐water slurry gasifier with hot‐oxygen burner (HOB) is presented. Experimental tests were carried out using diesel oil and coal‐water slurry in a bench‐scale entrained‐flow opposed multi‐burner (OMB) gasifier. Using a CCD camera equipped with high‐temperature endoscope, flame images inside the gasifier were recorded and subsequently processed. The results show that the HOB diesel flame is more stable than the normal two‐channel burner flame typically used. Entrained‐flow coal‐water slurry gasifiers can start up using the HOB directly without a higher preheated wall temperature. An HOB can potentially save gasifier preheating time and operation costs and enables a wide range of future applications.     

电子商务系统的安全问题及其解决方案

论述了现代电子商务的保密原理和安全技术 ,特别是近年来因特网上涌现出的新概念、新技术和最新解决方案 ,展示了安全技术在网上交易与支付系统中的应用     

省标《先张法预应力混凝土管桩基础技术规程》DBJ13-86-2007学习札记

偏心受压时,桩身结构承载力是否“可另外再提高20%”？当地下水或土对混凝土或混凝土中钢筋有弱腐蚀时,采用PHC管桩,规定壁厚“不应小于125mm＂是否合理？本文就省地方标准《先张法预应力混凝土管桩基础技术规程》这2项规定提出疑问。     

聚烯烃功能性棚膜的研究和应用进展

对近几年来聚烯烃功能性棚膜专用树脂、功能性助剂的开发以及功能性棚膜的加工配方和工艺研究进行了综述,指出采用棚膜专用树脂,选用受阻胺类复合耐老化体系、接枝反应型流滴防雾体系和稀土有机化合物转光体系等助剂,以及反应挤出成型技术是今后棚膜研究和生产的发展方向。     

掘进工作面迎头风量调控技术运用实践

通过对采区内掘进工作面各个时段迎头风量的调控，使采区范围内各用风地点风量分配趋近合理，采区范围内采、掘作业在时间和空间上尽量达到统一，保证矿井安全、正常有序生产。     

Visual-Quality Optimizing Super Resolution

In this paper, we propose a robust image super-resolution (SR) algorithm that aims to maximize the overall visual quality of SR results. We consider a good SR algorithm to be fidelity preserving, image detail enhancing and smooth. Accordingly, we define perception-based measures for these visual qualities. Based on these quality measures, we formulate image SR as an optimization problem aiming to maximize the overall quality. Since the quality measures are quadratic, the optimization can be solved efficiently. Experiments on a large image set and subjective user study demonstrate the effectiveness of the perception-based quality measures and the robustness and efficiency of the presented method.