累托石层孔材料在废水处理中的应用研究(Ⅷ)——层柱累托石的表征

研究了不同条件下制备的Ti/Zr层柱累托石,利用差热分析、红外光谱分析、X射线粉晶衍射、扫描电镜、BET比表面积分析等方法对层柱累托石的性能进行了表征.红外吸收光谱分析结果表明层柱反应只在层间域内进行,Ti/Zr层柱累托石不仅含有丰富的羟基,而且具有较强的热稳定性. X射线粉晶衍射分析结果表明:Ti基层柱累托石的层间高度可达1.8～1.9 nm;多金属聚合阳离子比单一金属聚合阳离子柱撑可获得更大的层间;钛层柱累托石经高温(400 ℃)焙烧开始出现锐钛矿新相.差热分析说明柱撑后的累托石的热稳定性大为增强.Ti/Zr层柱累托石的BET比表面积为202.434 m2/g,表面酸性＜+3.5,松散堆积密度为0.930 8 g/mL.     

速溶型聚丙烯酰胺的表征

通过微乳液法合成了高相对分子质量(Mr=1300万)粉状聚丙烯酰胺，采用FT—IR、SEM及DTG研究了聚合物的结构与其溶解性能的关系，并把该产品与国产及进口样品的综合性能数据进行了对照，研究结果表明：合成的聚丙烯酰胺具有纤维状、层状、孔状结构，这种结构是产品速溶的主要原因。     

多功能惯性器件及其加速度计部分的实验分析

既能感测载体的角运动，又能感测其线加速度的多功能惯性器件是惯性技术界十分感兴趣的。对于大角速率动调陀螺仪．若把压电敏感元件安装在陀螺仪限动器上，可构成大角速率多功能惯性器件。利用大角速率动调陀螺仪陀螺电机中特有的信号检测线圈，便于加速度信号的拾取。该文介绍了器件的工作原理、信号检测与处理及在不考虑陀螺仪部分时，线加速度计的测试结果。利用两个这种器件，即可构成满足大机动捷联惯导系统要求的惯性测量部件。     

Influence of mass transfer on thermogravimetric analysis of combustion and gasification reactivity of coke

Non-isothermal TG/DTG measurements are widely used to determine kinetic parameters of oxidation and gasification of carbons, e.g. by multi-heating rate methods. Thereby it is important to avoid spurious effects due to diffusion limitations. In this work, TG/DTG experiments with activated carbon were conducted under isothermal and non-isothermal conditions. The agreement of the experimental results with results of simulations based on the intrinsic kinetics, pore diffusion and external diffusion in/to the sample (crucible) is very good. The simulations show that mass transfer has an unwanted influence on TG measurements, if the concentration of the gaseous reactant (O₂ and CO₂) is too low and/or the heating rate is too high. Based on literature data, the simulation was extended to blast furnace coke with a very low reactivity and to highly reactive coke from pyrolysis of miscanthussinensis. The simulations and theoretical considerations lead to a criterion to exclude the influence of mass transfer on TG measurements a priori. This criterion is valid for combustion as well as for gasification with steam or carbon dioxide.     

Coal combustion: Correlation between surface area and thermogravimetric analysis data

A series of coals of different rank has been characterized by surface area measurements performed by sorption of both nitrogen and carbon dioxide. While the data obtained with nitrogen do not discriminate among the different coal samples, those based on carbon dioxide sorption do give a significant distinction between the samples. This technique has also been applied to the determination of the surface area of coal samples quenched after stepwise combustion in air atmosphere. It has been possible to establish a useful correlation between the latter data and the burning profile measured by derivative thermogravimetry. The aim of the present study was to gain a better understanding of the coal combustion process on a laboratory scale which could reasonably be extended to combustion plants. The results presented are relevant to some of the multivalent aspects inherent in the coal combustion process and some valuable information has been gained in respect of characterization of solid fuels.     

Thermal Decomposition Mechanism and Non Isothermal Kinetics of Complex of [La_2(P-MBA)_6(PHEN)_2]2H_2O

Ｏｗｉｎｇｔｏｔｈｅｖａｒｉａｔｉｏｎｏｆｃｏｏｒｄｉｎａｔｅｄｍｏｄｅｓｆｏｒｃａｒｂｏｘｙｌａｔｅａｎｉｏｎｓ ,ｍａｎｙｄｉｆｆｅｒｅｎｔｔｙｐｅｓｏｆｃｒｙｓｔａｌｓｔｒｕｃｔｕｒｅｓｆｏｒｔｈｅｒａｒｅｅａｒｔｈｃｏｍｐｌｅｘｅｓｗｉｔｈａｒｏｍａｔｉｃａｃｉｄａｎｄｎｉｔｒｏｇｅｎ ｃｏｎｔａｉｎｉｎｇｌｉｇａｎｄｓｗｅｒｅｏｂｔａｉｎｅｄ[1～ 4 ] .Ｔｈｅｉｒｔｈｅｒｍａｌｄｅｃｏｍｐｏｓｉｔｉｏｎｂｅｈａｖｉｏｒｈａｄｂｅｅｎｒｅ ｐｏｒｔｅｄｉｎｐｒｅｖｉｏｕｓｐａｐｅｒｓ[5～ 8] .…     

动力调谐陀螺仪子空间辨识

针对传统子空间辨识法(SIM)用于动力调谐陀螺仪(DTG)建模过程中存在的结构参数复杂、干扰因素未知、建模精度不高等问题,提出了一种改进的子空间辨识方法。首先,确定辨识对象DTG的状态空间模型集,分析DTG输出信号中存在的固有有色噪声。然后,针对有色噪声的干扰问题,对传统SIM进行改进,通过数据Hankel矩阵的正交投影消除传统SIM的有偏性。最后,在数值仿真中引入置信椭圆,对改进算法进行统计特性分析。仿真结果表明:在不同强度有色噪声干扰下,改进算法无偏,方差特性与有色噪声强度和数据长度有关。辨识实验表明:改进SIM的辨识效果明显优于传统SIM,辨识拟合度优于90%。得到的结果显示改进算法能够应用于DTG系统建模。     

水葫芦的热解行为研究

以水葫芦作为研究对象,采用热重分析仪在30~800℃条件下分别对水葫芦根、茎和叶不同部分的热分解行为进行了研究。结果表明,在温度达到800℃时,水葫芦的根与茎大约有80%分解,而叶基本分解完全;水葫芦的根茎叶在氮气和空气氛围下热解行为基本一致,在65℃左右,280℃左右和500℃左右有三个明显的失重峰。根据水葫芦根、茎和叶不同部位不同气氛下的TG/DTG图的对比分析,认为气氛对热解行为的影响较小,水葫芦的根、茎、叶应该以热分解为主,氧化分解部分不明显。     

THERMAL ANALYSIS AND DRYING KINETICS OF OLIVE BAGASSE

ABSTRACT

The slow thermal decomposition of olive bagasse at temperatures ranging from 25 to 900° C, with particular stress on the moisture evaporation phenomena, is analyzed making use of thermogravimetry, derivative ihermogravimelry and differential scanning calorimetry. The results obtained demonstrate that Thermal Analysis techniques contribute for the characterization of iniernai moisture transfer processes. “ Drying curves” obtained from Thermal Analysis experiments were compared with thin-layer drying curves of olive bagasse at relatively high temperatures. The existence of a critical moisture content, which distinguishes two types of water liaisons, was demonstrated, and its value quantified at 17-18%.     

NR／BR胎面胶的力学性能与其热行为的关系

热分析为橡胶复合物的分类和辨别提供了一项成功的技术。使用TGA和DTG研究天然橡胶（NR）和顺丁橡胶（BR）并用胶的热行为,以此来预测和定义其力学性能。DTG硫化曲线显示,天然橡胶的最初降解温度比顺丁橡胶的降解温度要低。根据TGA—DTG的图形轮廓,证实了两个与并用胶的力学性能十分有用的参数,一个是△Tmax（Tmax^BR100-Tmax^BRx）,另一个是NR／BR并用胶的峰高比率。