Thermodynamic database of the phase diagrams in the Mg-Al-Zn-Y-Ce system

The Mg-Al-Zn-Y-Ce system is one of the key systems for designing high-strength Mg alloys. The purpose of the present article is to develop a thermodynamic database for the Mg-Al-Zn-Y-Ce multicomponent system to design Mg alloys using the calculation of phase diagrams （CALPHAD） method, where the Gibbs energies of solution phases such as liquid, fcc, bcc, and hcp phases were described by the subregular solution model, whereas those of all the compounds were described by the sublattice model. The thermodynamic parameters describing Gibbs energies of the different phases in this database were evaluated by fitting the experimental data for phase equilibria and thermodynamic properties. On the basis of this database, a lot of information concerning stable and metastable phase equilibria of isothermal and vertical sections, molar fractions of constituent phases, the liquidus projection, etc., can be predicted. This database is expected to play an important role in the design of Mg alloys.     

NIT-Ph-p-BEN氮氧自由基的制备及催化降解性

以对醛基苯甲酸为原料，通过醛酸与2,3-二甲基-2,3-二羟胺基丁烷缩合，再经NaIO4氧化最终制得4-(4,4,5,5-四甲基-1,3-二氧化物)咪唑基-1-苯甲酸（NIT-Ph-p-BEN氮氧自由基）。采用FTIR、UV、ERP（电子顺磁共振波谱仪）和元素分析等对其结构进行表征；通过催化降解废水中有机染料甲基橙、甲基蓝和罗丹明B对其催化活性进行了评估。结果表明，当甲基橙、甲基蓝和罗丹明B浓度为15 mg/L，NIT-Ph-p-BEN质量浓度为0.15 g/L，H2O2浓度为30 mmol/L时，NIT-Ph-p-BEN对甲基橙有更好的催化降解性，仅在1 h内甲基橙的降解率达到94.26%。此外，反应机理表明，H2O2有助于实现NIT-Ph-p-BEN自由基的再生和循环利用。     

生物质中元素分布特征的聚类分析研究

测定了稻草秆、小麦秆、玉米秆、棉花秆、大豆秆、玉米芯、花生壳和柳树、松树、桦树、杨树、杉树 1 2个农业生物质和林业生物质种类 2 7个样品中主要元素 K,Ca,Na,Mg,Al,Fe,P和痕量元素 As,Cr,Co,Cu,Cd,Mn,Mo,Ni,Pb,Ti,Zn,V,Si,Ba,Be,Se,Sb,Ge,Hg的含量 ,并用SPSS聚类分析法分别进行了 R型和 Q型聚类研究 ,对这些元素在生物质中的分布特征进行了研究 .结果显示 :杨木、杉木和桦木与松木和柳木归成一大类 ,经济类作物黄豆秆和棉花秆分别归类后又归入一大类 ;农业生物质稻草秆和小麦秆、玉米秆被归入一类 ;虽然 2 7种生物质样品分别取自我国东北、华东、华北和西南地区 ,在地理位置上相距极远 ,但样品聚类谱系图表明 ,元素的分布特征与生物质的种类的关系显著 ,与产地的关系不明显 ,即元素的分布特征受种类的影响大 ,而受生长环境、气候、土壤条件的影响小 .     

基于退化四元小波变换的纸币识别

针对如何提取纸币图像特征和提高识别率的问题,综合利用退化四元小波变换具有的相位特性,提出一种基于退化四元小波变换的纸币识别方法.该方法首先对采集的纸币图像进行倾斜校正和边缘检测,然后运用退化四元小波对纸币图像进行分解操作,并对分解系数进行统计分析,将每个分解子带系数的能量和标准差作为该纸币图像的特征向量,最后将支持向量机作为分类器对纸币图像进行识别.本文方法在资源约束的嵌入式清分系统上实现,实验结果表明采用本文提出的算法突破了传统纸币识别系统识别率很难再提高的瓶颈,同时能够满足清分系统的实时性要求.     

生物基燃料乙醇生产工艺的能耗分析与节能技术综述

针对如何高效、经济和可持续发展生物质液体燃料这一问题,考察了淀粉质原料生产燃料乙醇的整个流程,从原料预处理到酒精脱水,尤其针对蒸馏、蒸煮液化等耗能较大的阶段,对不同的生产工艺技术进行了能耗比较,分析了不同的节能技术。通过大量的数据分析评述了最佳的技术路线,为燃料乙醇生产系统的节能降耗提出建议。     

Dynamic deviation reduction‐based concurrent dual‐band digital predistortion

This article introduces the concurrent dual‐band digital predistortion (DPD) architecture with only one upconvertion unit, which is suitable for the linearization of wideband power amplifiers (PAs) excited by concurrent dual‐band signals. By extending the conventional dynamic deviation reduction (DDR) model to the concurrent dual‐band mode, we propose two DDR‐based concurrent dual‐band models, the dual‐band DDR (DB‐DDR) model and the simplified dual‐band DDR (SDB‐DDR) model. The performance of these two models is experimentally assessed with two types of wideband PAs (a GaN Class F PA and a GaN Doherty PA) driven by the concurrent dual‐band signal, and compared with the prior two‐dimensional digital predistortion (2D‐DPD) model and the two‐dimensional modified memory polynomial (2D‐MMP) model. The results prove the good DPD performance and low computational complexity of the proposed models. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:401–411, 2014.     

乙烯装置急冷油系统减粘技术的研究

基于乙烯装置急冷油和急冷系统结垢物的组成分析，探讨了急冷油增粘和系统结垢的机理．研究了适用于急冷油系统的新型减粘剂RIPP-1420和减粘剂的注入技术。结果表明，RIPP-1420减粘剂和该注入技术能有效降低急冷油系统物料的粘度，减少结垢物的生成。     

Ultrahigh molecular weight polyethylene/polypropylene/organo‐montmorillonite nanocomposites: Phase morphology,rheological, and mechanical properties

Phase morphology, rheological, and mechanical properties of ultrahigh molecular weight polyethylene (UHMWPE)/PP/organo‐montmorillonite nanocomposites were investigated in this work. The results of TEM and XRD indicated that the organo‐montmorillonite PMM prepared with the complex intercalator [2‐methacryloyloxyethyldodecyldimethylammonium bromide/poly(ethylene glycol)] were exfoliated and dispersed into UHMWPE matrix, and the synergistic effect of the complex intercalator on the exfoliation and intercalation for montmorillonite occurred. Besides, the presence of PMM in UHMWPE matrix was found able to lead to a significant reduction of melt viscosity and enhancement in tensile strength and elongation at break of UHMWPE, except that izod‐notched impact strength was without much obvious change. The dispersed PMM particles exhibited a comparatively large two‐dimensional aspect ratio (L_clay/d_clay = 35.5), which played an important role in determining the enhancement of mechanical properties of UHMWPE nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

加压条件下电梯活塞效应及疏散可行性分析

通过对电梯井加压和不加压条件下电梯运行活塞效应引起的电梯井内、建筑空间及外界之间的气体流动规律分析,确定火灾条件下烟气是否会卷入前室的临界质量流率。研究结果表明,只对电梯井的一个开口集中加压时,加压质量流率达到临界质量流率以上,活塞效应就不会引起加压损失;对电梯井上下部都加压时,上下加压质量流率各在临界质量流率的一半以上,活塞效应才不会引起加压损失。对于现状条件下的大多数电梯,特别是多梯井,通过设计来防止活塞效应引起烟气卷入前室是可行的。     

煤化学链燃烧颗粒流动反应的数值模拟

针对化学链燃烧气固反应速率的影响因素复杂未知的问题,本文建立了碳粒与CaSO4载氧体颗粒在水蒸气气氛下的数理模型,并利用Fluent进行数值计算,从微观上分析了温度和压力的改变,对颗粒间化学链燃烧反应速率、CO2生成速率以及载氧体表面固相生成物沉积速率的影响。分析结果表明,提高反应器内的温度和压力,均加快了CaSO4载氧体颗粒表面CaS的沉积速率,且压力的提高在很大程度上促进了沉积速率的增加,而沉积覆盖在载氧体表面上的CaS导致了反应速率的下降。该研究有利于高纯度CO2气体的捕集,从而达到减排的目的,对化学链反应速率的控制具有重要意义。