基于DoG检测图像特征点的快速二进制描述子

针对SIFT描述子实时性差和传统二进制描述子对尺度、旋转和视角变化鲁棒性差的问题,本文通过优化采样模式和添加灰度差分不变量比较测试进行改进,提出了一种鲁棒性更高的二进制描述子。首先,设计了一种尺度关联、编号标记的采样模式;然后,旋转采样模式中各采样点到特定位置,确保描述子尺度、旋转不变性;接着,分析了采样点点对模式对描述子的影响,选择使用机器学习训练后的128对采样点对;最后,选择灰度值比较测试及梯度绝对值和比较测试构建二进制描述子。实验中采用DoG检测图像关键点,结果表明:本文提出的描述子在描述子构建和描述子匹配上比SIFT描述子分别快84%和67%;在有视角变化的图像匹配上,准确率比传统的二进制描述子高3%~5%,召回率平均要高30%以上。本文提出的特征点描述方法适用于时间要求高的图像匹配领域。     

Synthesis of a novel DOPO‐based polyphosphoramide with high char yield and its application in flame‐retardant epoxy resins

A novel and highly effective flame retardant (FR), DOPO‐TPMP oligomer, was synthesized by a simple condensation of 4‐(hydroxymethyl)‐2,6,7‐trioxa‐1‐phosphabicyclo[2.2.2]octane‐1‐oxide and phosphorus oxychloride followed by a polycondensation reaction with 6‐(2,5‐dihydroxyphenyl)‐6H‐dibenzo[c,e][1,2]oxaphosphinine‐6‐oxide. The chemical structure of DOPO‐TPMP was well characterized using Fourier transform infrared and NMR spectra. DOPO‐TPMP was used as an additive‐type FR for epoxy resin (EP). The FR properties of the resultant EP composites were investigated by limiting oxygen index (LOI) test, UL‐94 vertical burning test and cone calorimeter measurements. Specifically, the EP composite containing 10.0% DOPO‐TPMP achieved a LOI value of 36.1%, V‐0 rating in the UL‐94 test and a 58% reduction in peak heat release rate. Further mechanism analysis attributed the enhanced flame retardancy to the increased char yield on the addition of DOPO‐TPMP. © 2019 Society of Chemical Industry     

全过程集成管理服务在西安地铁5号线二期工程的应用

近年来,我国不断推动房地产和市政工程建设实施全过程工程咨询管理,即全过程集成管理服务.西咸轨道投资建设公司成立时间短、人员少,却仅用了一年零三个月的时间,完成了西安地铁5号线二期车站设备系统的工程建设任务,这得益于全过程集成管理模式的应用.     

Effect of Al2O3/CaO on the melting and mineral transformation of Ningdong coal ash

Coal ash melting characteristics has a direct impact on the smooth operation of entrained gasifier. Mineral conversion of coal ash is very significant to be investigated, because the mineral can affect the melting temperature and viscosity under high temperature conditions. In this paper, the effects of different Al₂O₃/CaO on the mineral conversion, melting temperature and viscosity of Ningdong coal ash are studied by the combination of experiment and simulation. The trend of melting temperature decreases firstly and rises with increasing Al₂O₃/CaO. The ash melting point reached to the lowest when the ratio is 1.23. XRD and Factsage software are used to analyze crystallization behavior of samples. The results show that the content of anorthite, albite and corundum increases and subsequently decreases, while the content of mullite decreases firstly and then rises with increasing Al₂O₃/CaO. High content with CaO can contribute to form albite and anorthite of low-melting. Besides, high content with Al₂O₃ can tend to produce mullite of high-melting. The results of experimental and simulation are basically the same, which lays a foundation for the melting characteristics of Ningdong coal ash and can provide technical support for the smooth operation of the entrained-gasifier.     

In situ Raman spectroscopic study towards the growth and excellent HER catalysis of Ni/Ni(OH)2 heterostructure

The electrochemical water splitting to produce H₂ in high efficiency with earth-abundant-metal catalysts remains a challenge. Here, we describe a simple “cyclic voltammetry + ageing” protocol at room temperature to activate Ni electrode (AC-Ni/NF) for hydrogen evolution reaction (HER), by which Ni/Ni(OH)₂ heterostructure is formed at the surface. In situ Raman spectroscopy reveals the gradual growth of Ni/Ni(OH)₂ heterostructure during the first 30 min of the aging treatment and combined with polarization measurements, it suggests a positive relation between the Ni/Ni(OH)₂ amount and HER performance of the electrode. The obtained AC-Ni/NF catalyst, with plentiful Ni–Ni(OH)₂ interfaces, exhibits remarkable performance towards HER, with the low overpotential of only 30 mV at a H₂-evolving current density of 10 mA/cm² and 153 mV at 100 mA/cm², as well as a small Tafel slope of 46.8 mV/dec in 1 M KOH electrolyte at ambient temperature. The excellent HER performance of the AC-Ni/NF could be maintained for at least 24 h without obvious decay. Ex situ experiments and in situ electrochemical-Raman spectroscopy along with density functional theory (DFT) calculations reveal that Ni/Ni(OH)₂ heterostructure, although partially reduced, can still persist during HER catalysis and it is the Ni–Ni(OH)₂ interface reducing the energy barrier of H1 adsorption thus promoting the HER performance.     

湿法回收钒高氨氮废水处理工程实例

湿法提钒回收处理过程中的废水具有高硬度、高含盐、高氨氮等特征,采用预处理+负压亚沸碱析脱氨及微负压氨回收工艺,可使出水水质稳定氨氮达到15 mg/L以下,同时超级吸氨器以及两级氨水吸收罐可制得浓度为18％～25％的氨水作为产品,降低项目整体运行费用.