红外光谱等方法对某未知样品的定性定量分析

利用红外光谱，热分析及红外光谱－色谱联联用技术对某未知样品进行了分析。通过分析。可知该物质为丙三醇硬脂酸单脂。并含有少量的硬脂酸甲酸和十六烷基酸甲酯，这两种微量物物质的比为1：2。     

病原菌诱导黄瓜产生交互保护作用的数学模型研究

以中国农业科学院蔬菜花卉研究所开展的生物试验为研究背景,建立了病原菌诱导黄瓜产生交互保护作用的数学模型,揭示了交互保护作用下病情指数的变化规律,并利用常微分方程定性理论分析了模型的动力学性态,最后通过数值实验进一步验证了交互保护作用效果.合理利用交互保护现象,可以减少农药使用,对于环境保护和食品安全等方面都具有十分重要的意义.     

合成氨装置101D堵塞物中晶体定性分析

基于Boentgen、Laue与Ewald、W.H.Bragg及W.L.Bragg、Friedrich和Knipping等前辈X射线及其晶体学的研究与发现,X射线晶体结构分析已成为研究原子或离子在晶体点阵中结合、鉴定晶体化合物空间结构的可靠方法.Debye-Scherrer粉晶X射线衍射法(XRPD)在合成氨装置101D工况技术分析中,比较有意义的实际应用是解决由不同单质或化合物组成的复杂混合堵塞物中晶体的鉴定问题.采用XRPD定性分析了合成氨装置101D堵塞物样品中的主要晶体成分.实验结果表明:本法对合成氨装置101D工况技术分析具有重要的意义.     

Stability Analysis and Design of Impulsive Control Lorenz Systems Family

Lorenz systems family unifying Lorenz system, Chen system and Lü system is a typical chaotic family. In this paper, we consider impulsive control Lorenz chaotic systems family with time-varying impulse intervals. By establishing an effective tool of a set of inequalities, we analyze the asymptotic stability of impulsive control Lorenz systems family and obtain some new less conservative conditions. Based on the stability analysis, we design a novel impulsive controller with time-varying impulse intervals. Illustrative examples are provided to show the feasibility and effectiveness of our method. The obtained results not only can be used to design impulsive control for Lorenz systems family, but also can be extended to other chaotic systems.     

Asymptotic Stability Properties of $\theta$-Methods for the Multi-Pantograph Delay Differential Equation

This paper deals with the asymptotic stability analysis of $\theta$–methods for multi-pantograph delay differential equationHere $\lambda, μ_1,μ_2, ... , μ_l, u_0 \in C$.In recent years stability properties of numerical methods for this kind of equation has been studied by numerous authors. Many papers are concerned with meshes with fixed stepsize. In general the developed techniques give rise to non-ordinary recurrence relation. In this work, instead,we study constrained variable stpesize schemes, suggested by theoretical and computational reasons, which lead to a non-stationary difference equation. A general theorem is presented which can be used to obtain the characterization of the stability regions of $\theta$–methods.     

Pr数对环形浅液池热毛细对流的影响

为了解流体普朗特数(Pr)对热毛细对流的影响,通过线性稳定性分析,确定了环形浅液池内硅熔体(Pr＝0.011)和几种硅油(Pr数从6.7至57.9)热毛细对流失稳的临界条件,获得了它们在临界条件下的热流体波,特别是高Pr数硅油的热流体波.结果发现:当Pr≤15.9时,临界Ma数随Pr数的增加迅速上升,此时环形池内只有一...     

小波变换法在X射线能谱去噪声中的应用

阐述了二进小波变换法的去噪声原理和方法,并将其应用于X射线能谱分析中噪声的去除。实验结果表明,该去噪方法能够解决传统平滑方法的滑方法的不足,改善X射线能谱的定性、定量分析结果。     

化工原理填料吸收塔与板式精馏塔计算问题类比教学的探讨

Analogy teaching of calculation of packing absorption column and plate tower of distillation was studied in this paper. Firstly, a detailed analogy of the above calculation problems was studied according to the frame of calculation type, calculation basis, quantitative calculation and qualitative analysis. Secondly, the qualitative analysis of the above calculations was used as examples to illustrate the analysis methodology. Students could master very well the sameness and difference of the calculation of absorption and distillation through analogy teaching.     

气相色谱法测定废气和空气中20种C1~C6烃类化合物的含量北大核心CSCD

石化企业在油品的生产加工过程中不可避免地会产生大量小分子烃类化合物,这些小分子烃类化合物来源广泛、种类繁多、毒性大、处理工艺比较复杂[1-3]。目前石化企业工作场所空气和固定污染源废气多采用综合指标表征,缺少特征因子的检测,现有国家标准也缺乏废气组成的定性分析及常见低分子烃的定量分析方法,因此需要开发定性、定量分析空气和废气中小分子烃类化合物的方法。     

循环伏安法定性分析矿物中某元素硫氧化物占比

根据硫化矿和氧化矿在电解液为硫酸钠的三电极体系中循环伏安曲线的差异,建立了循环伏安法定性分析矿物中某元素硫氧化物占比的方法,以铜的硫化物(黄铜矿)和氧化物(孔雀石)纯矿物进行循环伏安法测试。结果表明,在扫描速率0.1 V/s,扫描电压范围-0.8 V～0.8 V时,黄铜矿循环伏安曲线出现氧化还原峰,孔雀石循环伏安曲线未见明显氧化还原峰;黄铜矿和孔雀石混合物循环伏安曲线上的氧化还原峰电位与单一黄铜矿的氧化还原峰电位几乎一致,但峰电位对应的电流大小与矿物占比存在一定的关系。由此,可以通过循环伏安法定性判断混合矿中黄铜矿与孔雀石的占比,实现循环伏安法定性分析矿物中某元素硫氧化物占比。