烟草中挥发性与半挥发性有机酸的GC-MS法快速检测

建立了气相色谱-质谱联用同时测定烟草中25种挥发性与半挥发性有机酸的快速定量分析方法。样品经二氯甲烷震荡萃取,N,O-双(三甲基硅基)三氟乙酰胺(BSTFA)硅烷化,以反-2-己烯酸和肉桂酸双内标法定量,利用GC-MS/SIM法同时测定了25种挥发性、半挥发性有机酸。结果表明:此方法测定有机酸具有良好的线性(r2≥0.985)和重复性(RSDs≤8.93%,n=5),平均回收率81.43%~100.58%,检测限为0.03~2.30μg/g,定量限为0.10~7.67μg/g。建立的方法简便快捷,且具有较高的准确度和精密度,适用于烟草中挥发性与半挥发性有机酸的快速和同时测定。     

土壤生物修复剂在烟田中的应用效果

从烟叶生物学性状、烟株抗病性、产值、土壤理化性质、土壤微生物菌群5个方面介绍土壤生物修复剂在烟田中的应用效果。试验结果表明,土壤生物修复剂应用于烟草生产中,可促进烟草生长发育;提高烟株的抗病性,并对烟田土传病害有一定的抑制作用;提高烟叶产量及品质,增加经济效益;改善土壤板结,增强土壤保水保肥能力;提高微生物活力,改善土壤环境。     

香料烟中游离糖的毛细管气相色谱分析

为便于分析香料烟中游离糖质量分数与其品质的关系，建立了游离糖质量分数的气相色谱分析方法。该方法回收率高（93．7％－98．7％），相关性好（0．9995－0．9998），衍生化试剂选择较为理想。从对云南、新疆香料烟中游离糖的定量分析结果看，随着香料烟等级的提高，葡萄糖质量分数明显提高，且两产区的游离糖质量分数差异较大。     

Anxiety, anxiety disorders, tobacco use, and nicotine: A critical review of interrelationships.

Smoking is highly prevalent across most anxiety disorders. Tobacco use increases risk for the later development of certain anxiety disorders, and smokers with anxiety disorders have more severe withdrawal symptoms during smoking cessation than smokers without anxiety disorders. The authors critically examined the relationships among anxiety, anxiety disorders, tobacco use, and nicotine dependence and reviewed the existing empirical literature. Future research is needed to better understand the interrelationships among these variables, including predictors, moderators, and mechanisms of action. Increased knowledge in these areas should inform prevention efforts as well as the development and improvement of smoking cessation programs for those with anxiety and other psychiatric disorders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Discrete-time multiserver queues with priorities

We analyze the performance of discrete-time multiserver queues that use a priority structure in the scheduling of departures. Such systems are often encountered in the context of ATM and in voice-data multiplexing. The arrival process is iid from slot to slot with a general distribution for the batch sizes. The analysis of both system contents and delay makes extensive use of generating functions and yields simple formulas to evaluate important performance measures such as mean values, variances and tail probabilities of these random variables. A numerical example illustrates the results of the analysis and shows that using priorities and sharing resources can lead to a considerable improvement of system performance.     

西门子PLC在龙口缆机电控系统中的应用

本文主要介绍了由S7-300PLC，SRM6100无线电台和西门子调速器组成的龙口缆机电控系统，该系统在实时性，稳定性，安全性和灵活性方面满足了龙口缆机的工艺要求。重点阐述了该缆机的工艺要求，硬件配置及电控系统的功能。同时，介绍了该系统调试及投入运行过程中出现的问题及解决的方法。     

Computing failure probabilities. Applications to reliability analysis

The paper presents one method for calculating failure probabilities with applications to reliability analysis. The method is based on transforming the initial set of variables to a n-dimensional uniform random variable in the unit hypercube, together with the limit condition set and calculating the associated probability using a recursive method based on the Gauss–Legendre quadrature formulas to calculate the resulting multiple integrals. An example of application is used to illustrate the proposed method.     

云南香料烟中糖和烟碱的累积研究

研究了云南保山香料烟产区冬春和夏季香料烟生长发育期间叶片中总糖、淀粉和烟碱的累积规律.结果表明,与夏季香料烟相比,冬春香料烟的总糖含量较高、烟碱含量较低、糖碱比较高;发育过程中积累的淀粉较多,烟碱含量变化不大,甚至下降.说明冬春烟积累糖类物质的能力较高,但其烟碱合成积累能力则不足,可能与其生长发育的季节有关.     

3,5-二硝基水杨酸比色法测定废烟草中总糖

对3,5-二硝基水杨酸比色法测定总糖含量的条件进行了研究,结果表明:最佳比色波长为540 nm,显色剂的最佳用量为2.5 mL,沸水浴时间为5 min.对废烟草样品进行测定,试验表明:该方法在2-240μg.mL-1浓度范围内遵循比耳定律,呈线性关系(R=0.999 3),变异系数为0.46%,平均回收率为98.9%,该法的准确性和精密度均较好.与经典的斐林试剂法相比,具有操作简便、快速、测定成本低等特点.尤其适合于低浓度糖样的测定.     

智能控制在烟厂烟丝烘干控制系统中的应用

本文给出了烟丝烘干系统的控制策略,利用仿人智能控制实现了烟丝烘干系统的控制,给出了该控制器的详细设计。