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1.
选用3种煤分别制得3种粒度的试样。采用非定温测量法进行TG分析,得到相应的TG/DTG曲线,选定煤自燃过程中的6个特征温度,并确定其温度界限,分析不同粒度煤样特征温度的变化并总结规律。结果表明,高位吸附温度和着火温度基本保持不变,其余4个特征温度的变化规律不尽相同。  相似文献   

2.
以外墙保温板残料活性炭为吸附剂,采用吸附的方法净化实验室含芘废水中的芘。探讨了活性炭对芘的吸附性能及吸附模型。结果表明:活性炭对芘的定温吸附符合定温吸附Freundlich模型,吸附以物理吸附为主,室温下芘的饱和吸附量为106mg/g。  相似文献   

3.
外墙保温板残料作原料制备活性炭既解决了保温板废料难处理问题,又解决了活性炭的原料问题,是一种极佳的提升废料价值的方式。本文通过实验讨论了水蒸气活化法制备的外墙保温板残料活性炭对碘的吸附行为和能力。以酚醛树脂类外墙保温残料为原料,在活650℃化温度,30mg/h的水蒸汽流量,活化30min制备的活性炭对碘的定温吸附符合Langemuir定温吸附模型,吸附以化学吸附为主,室温下饱和吸附量为839.2mg/g。  相似文献   

4.
碳酸氢铵热分解动力学研究   总被引:1,自引:0,他引:1  
本文用热重法(TG)研究了碳酸氢铵的热分解反应,测算出其反应级数,定温下的速度常数,进而推算出活化能,频率因子等动力学数据。  相似文献   

5.
研究不同拉伸条件(热拉温度、拉伸比、拉伸速率、预热温度及时间,热定型温度及时间)对薄膜微孔的影响,并确定最优拉伸工艺为在预热温度100℃,定温时间5min,拉伸温度为110℃以及热定型温度120℃,定温时间5min下,热拉程度60%:先萃取后拉伸工艺,拉伸速率为30mm/min,先拉伸后萃取工艺,拉伸速率为10mm/min时,拉伸出的微孔数量较多且分布均匀。因此,为了得到孔径比较均匀且量较多的微孔膜,拉伸程度不宜过大,拉伸速率较小。  相似文献   

6.
从自加速分解温度(SADT)评价含能物质的热危险性出发,分析了联合国危险物运输专家委员会推荐的几利-方法对含能材料热危险性评价的局限性,简述了与热分析法相关的测定含能材料自加速分解温度的方法,主要有加速量热仪法、TG—DTA、DSC、微量热法、动力学模拟法、绝热自点火实验法等。同时对各种方法的优缺点分别进行了分析,讨论了热分析法评价含能材料热危险性的发展趋势。  相似文献   

7.
针对现有日用陶瓷抗热震性测定方法存在的局限性,在GB/T 3298-2008采用定温冷热循环的基础上,提出了评价日用陶瓷抗热震性的阶梯温差法新方法。结果表明:该方法适合于日用陶瓷产品抗热震性的评价。通过对不同材质、相同材质不同器型产品的阶梯温差法试验,确定了不同产品抗热震性适用的温度范围,初步建立了不同产品抗热震性合格判定指标。通过该方法的评价,能让企业和消费者定量了解产品的抗热震性情况,指导生产和了解产品的温度使用范围。  相似文献   

8.
碳化硅纳米粉体性能优于传统的碳化硅粉体,能够达到高新技术领域的严格要求,具有更为广泛的用途。综述了近年来在高新技术领域发展起来的碳化硅纳米粉体的制备方法,对一些新的制备方法进行了重点介绍,阐述了各种方法的基本原理、特点及研究现状,并对各种方法进行了比较。碳热还原法原料便宜,质量稳定,易实现工业化生产;液相法可制得纯度高的纳米级微粉;气相法是目前比较先进的方法,但不易实现大批量生产。未来碳热还原法将继续占主导地位,提出了该领域科学工作者的努力方向。  相似文献   

9.
采用三种不同的动力学分析方法,即Freeman方法、Flynn-Wall-Ozawa以及Kissinger方法对不同类型聚乙烯的热分解动力学进行了探讨。结果表明,Flynn-Wall-Ozawa法I、Friedman法的测试结果与三者聚乙烯的结构特征较吻合,不同聚乙烯降解活化能的大小顺序为HDPE>LLDPE>LDPE。  相似文献   

10.
本文介绍了美国五种用于测定PUF及其制品阻燃性能的新方法,它们是:美国FMUSS-302法,美国加州117A法,117D法,TB133法及TB129法。文中汇集了这些方法的试验装置、试验条件及通过标准。这五个方法目前均未在我国应用,但可供借鉴。此外,本文对可用于测定材料多种阻燃参数的小型锥形量热计的原理及应用也做了简要的叙述。  相似文献   

11.
<正>2.7用承载的Pd作催化剂村田和久等人介绍了一种用Ti-MCM-22和Pd化合物的混合物作催化剂,使丙烯与O2在液相中反应来生产PO的工艺[28]。MCM-22用水热-煅烧法合成,然后用溶浸法使Ti化合物承载,在空气中  相似文献   

12.
从化学法和生物法两个方面系统地总结了手性β-羟基酸的合成方法,并通过分析和比较各种方法的优缺点,对合成手性β-羟基酸的发展前景进行了展望.  相似文献   

13.
There are several methods available to measure chlorophyll in canola oil and seed, and these will not necessarily yield the same results and should not be used in terchangeably. Total chlorophyll was determined for samples of canola seed and commercial canola oil by recognized spectrophotometric methods and by high-performance liquid chromatography (HPLC). The HPLC method, which summed all chlorophyll-related pigments detected, found approximately 1.4 times more total chlorophyll per sample than did the spectrophotometric methods. The spectrophotometric methods are calibrated with only chlorophyll a and underestimate other chlorophyll pigments, which have lower extinction, coefficients and different absorption maxima. The HPLC method detects each pigment at its absorption maxima and applies the appropriate absorptivity factor. Care must be taken when comparing results obtained by different methods. There appears to be a need for a standardized method of chlorophyll pigment measurement by HPLC.  相似文献   

14.
章艺  彭西高 《耐火材料》2006,40(6):460-463
详细介绍了近年来国内外铝电解槽用耐火材料抗冰晶石侵蚀测试方法的现状,系统分析比较了各种测试方法的优缺点。从耐火材料检测实践出发,提出了根据耐火材料实际应用状况和材料种类来选择适当的检测方法。全部浸入法和半浸入法适用于电解槽侧壁耐火材料,坩埚法主要适用于散状耐火材料。  相似文献   

15.
Methods for the determination of O/M ratios in uranium and uranium-plutonium oxide nuclear fuels are reported based on an extensive literature survey. The salient features, as well as the merits and drawbacks of each method are critically reviewed. The need for a fast direct method, by which the simpler indirect methods may be checked, is met by the carbon-reduction method.  相似文献   

16.
We have recently presented a new methodology for screening different signal analysis methods in combination with signal pre-treatment methods with the goal to effectively identify those combinations that are highly selective towards a specific process change (Bartels et al., Ind. Chem. Eng. Res. 48 (2009) 3158-3166). The main outcome of the methodology is visually represented in an overall result matrix with coloured tiles illustrating a measure for the suitability of each combination of analysis method and signal pre-treatment. Suitable methods can be visually identified very quickly.For the early detection of agglomeration in fluidized beds we illustrate this methodology by four different cases: two cases from a pilot-scale bubbling bed, one from an industrial scale bubbling bed and one case from a lab-scale circulating bed. With the result matrix for each case several suitable methods are identified. The data are also evaluated to identify methods that are more generally applicable for a range of different cases. The suitability of a positively identified method is subsequently analyzed for its temporal response to both agglomeration and other effects. The influence of the different data pre-treatment methods is also addressed.  相似文献   

17.
A more accurate method (comparing to the Euler, Runge–Kutta, and implicit Runge–Kutta methods) for the numerical solutions of ordinary differential equations (ODEs) is presented in this paper. The coefficients in the approximate solution for the ODE using the proposed method are divided into two groups: the fixed coefficients and the free coefficients. The fixed coefficients are determined by using the same way as in the traditional Taylor series method. The free coefficients are obtained optimally by minimizing the error of the approximate solution in each time interval. Examples are presented to compare the numerical solutions of the Rahmanzadeh, Cai, and White's method (RCW) to those of other popular ODEs methods.  相似文献   

18.
化学法制备ZrO2超细粉体   总被引:1,自引:0,他引:1  
唐志阳 《佛山陶瓷》2004,14(4):34-36
摘介绍了化学法制备ZrO2超细粉体常用的几种方法:沉淀法、溶胶-凝胶法、水热法、沉淀-乳化法等;介绍了各种制备方法的工艺流程及其特点。  相似文献   

19.
邻、间、对苯二甲酰氯的合成工艺   总被引:2,自引:0,他引:2  
介绍了以邻苯二甲酸酐为原料,采用光气法、氯化亚砜法或氯代烃法等制备邻苯二甲酰氯的工艺和以间/对苯二甲酸为原料,采用光气法、氯化亚砜法、金属氧化物法、羧酸/酉自法等制备间/对苯二甲酰氯的工艺,对各合成方法的优缺点进行了评价。通过工艺对比可知,以邻苯二甲酸酐或间屑寸苯二甲酸为原料,采用光气法和氯化亚砜法制备邻苯二甲酰氯或间/对苯二甲酰氯的工艺应用广泛;以间/对二甲苯为原料,先生成间/对六氯二甲苯,再与对应的苯二甲酸或者酯反应制备间履寸二甲酰氯的方法最经济。  相似文献   

20.
There are some computational models for fluids viscosity calculation. However, each of these models is reliable in confined density. In this comparative study two methods are evaluated for viscosity prediction in all range of density. We determine the effectiveness of each of the models and we demonstrate the strengths and weaknesses of them. Viscosity of the six refrigerants is calculated by some computational models based on Chapman⿿Enskog and Rainwater⿿Friend theories. Then a feed forward artificial neural network (ANN) with multilayer perceptrons is used to viscosity prediction and finally two methods (computational models and artificial neural network) are comparing. It is concluded that there is no opinion by computational methods to calculate viscosity from low to high density. The results show that prediction accuracy of computational models in low and moderate densities is good as ANN method. However artificial neural network has very good accuracy in high densities while computational method is defeated when the density is more than 8.  相似文献   

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