构建广电网络骨干光缆监测管理系统

主要介绍光缆线路自动监测系统的工作原理、组成结构和功能，针对广电行业的实际业务需求，比较了不同类型监测方法的优势和应用于广电城域骨干网光缆线路自动监测系统的解决方案，最后指出构建广电网络骨干光缆监测管理系统的前瞻性与扩展性。     

基于多层字典的自重构目标跟踪算法

针对视觉跟踪系统中常用的模板处理方法很难 适应目标外观和视频背景不断变化的不足,提出一种基于多层字典的自重构 目标跟踪算法。通过构建多层字典,分别从时间和 空间上增强目标描述能力,既可以刻画目标局部细节,又蕴含了目标整体信息;在跟踪过程 中,模板可以利 用多层字典根据前景和背景的复杂性自适应地分裂与分并,分裂出多个跟踪器从不同角度进 行跟踪,有效地 提高定位精度,也可以合并子模板以达到降低系统的计算负荷。定性和定量分析的实验结果 表明,本文算法具 有良好的跟踪精度和运行效率,可以较好地应对变化与遮挡。     

简易数字存储示波器的设计

随着电子通信以及教学事业的发展,示波器的应用越来越广泛,它在教学中所起到的作用越来越重要,示波器可以测量信号的幅度,频率以及波形等等,但是高精度的示波器非常昂贵,对于非盈利事业的教学组织来说无疑不合适,所以提出了一种以单片机为控制核心的简易示波器设计方案。它由前向控制部分,数据采集和存储部分,51单片机控制部分以及按键和MS12864R显示部分组成。     

卷烟商标残留成份SPME-GC/MS分析

本文建立了一种研究卷烟商标残留挥发性有机物(VOCs)的快速分析方法。利用顶空固相微萃取(HS-SPME)技术对样品进行前处理,与GC-MS联用对卷烟商标残留有机挥发性成份进行分析。并对纤维头类型、平衡时间、萃取温度等参数进行了优化,着重对SMPE重复性进行了讨论。确定SPME条件为65μmCW/DVB纤维头、平衡时间为20min、萃取温度为100℃。结果表明该方法可有效地分析羟基环已基苯甲酮、二苯甲酮、酯类化合物以及苯系物,为卷烟商标质量控制与有害成份监控提供依据。     

顶空-气质法测定食品包装材料中的4种有害物

目的研究食品用塑料包装材料中4种有害单体(1,3-丁二烯、丙烯腈、乙苯、苯乙烯)的顶空-气质联用检测方法。方法塑料包装材料经液氮粉碎、顶空加热后,采用质谱检测器对顶空气体进行检测,通过标准物质扫描获得目标物定性、定量离子,通过标准曲线绘制对目标物进行定性定量。结果 1,3-丁二烯、丙烯腈在0.02～2 mg/mL,乙苯、苯乙烯在0.1～10 mg/mL范围内线性良好,方法检出限分别为0.05,0.05,0.02,0.02mg/kg。对4种单体进行了加标回收试验,平均回收率在94.42%～106.07%之间,相对标准偏差为2.76%～5.91%。结论建立了食品用塑料包装材料中4种有害单体的顶空-气质联用检测方法,该方法检出限更低,节省了样品的前处理时间,为食品包装用塑料材料中有害单体的快速检测提供了方法指导。     

Changes of volatile compounds in wine vinegars during their elaboration in barrels made from different woods

Changes in the volatile components of red wine vinegars and balsamic vinegars were investigated during 1 year of aging in wood barrels and bottles. Barrels of four different woods (oak, chestnut, acacia and cherry) were used. A total of 57 volatile compounds were analysed by Gas Chromatography–Flame Ionization Detection (GC–FID) and Headspace Sorptive Extraction GC–Mass Spectrometry (HSSE-TD–GC–MS). We observed significant increases in the total content of volatile compounds only for balsamic vinegars. The concentrations of ethyl furoate, ethyl benzoate, benzaldehyde and acetophenone were highest in cherry barrels. These compounds, then, seem to be characteristic of this wood. Oak lactones presented the highest increases for vinegars aged in oak. Eugenol was only present in vinegars aged in chestnut and oak barrels. Oak and cherry seem to be the best type of wood for aging of vinegar due to their distinctive aromatic characteristics.     

Diosgenin quantification,characterisation and chemical composition in a tuber collection of Dioscorea spp. in the state of Jalisco,Mexico

Dioscorea spp. tubers are known commonly as camote de cerro to the state of Jalisco, México. Besides its use as food, it contains diosgenin, a raw material used widely for synthesising steroid hormones. The purpose of the present research was to determine diosgenin contents by gas chromatography‐mass spectrometry (GC‐MS), as well as physical and chemical characteristics of sixty Dioscorea spp. accessions cultivated in mesh shade coming from eleven localities in the state of Jalisco. Extraction protocol for diosgenin was maceration combined with ethanol 80%. Significant statistical differences for diosgenin content were found between accessions, finding levels between 0.02 and 0.16 mg kg^?1 in dry basis. Length, weight tuber, proportion pulp/skin, percentage of pulp and percentage of skin showed significant differences. Chemical composition based in fresh weight presented in moisture percentage a range of 71.93–83.26%, crude protein 1.42–1.74%, ashes 0.80–1.16%, lipid 0.13–0.17%, crude fibre 3.80–4.02% and total carbohydrates 13.97–25.44%. Results show that tubers from Jalisco can be an important source of nutrients for consumers.     

Composition and antibacterial activities of essential oils of seven Ocimum taxa

GC/MS was used to identify compounds of essential oils from seven Ocimum taxa (O. americanum L., O. basilicum L., O. campechianum Mill., O. x citriodorum Vis., O. kilimandscharicum Baker ex Gürke and three botanical varieties and cultivars of Ocimum basilicum L.: ‘Genovese’, var. difforme and var. purpurascens). Preliminary screening of their antibacterial activity was done against a number of common pathogens (Enterococcus faecalis, Enterococus faecium, Escherichia coli 0157:H7, Listeria monocytogenes, Listeria ivanovii, Proteus vulgaris, Staphylococcus aureus, Staphylococcus epidermis) using the filter paper disc agar diffusion technique, while further analyses were done by modification of the disc diffusion method. A broad variation in the antibacterial properties of investigated essential oils was observed. E. coli 0157:H7 was inhibited by O. basilicum ‘Genovese’ essential oil, while Ocimum americanum and Ocimum x citriodorum essential oils were the most effective against Enterococcus faecalis, Enterococcus faecium, P. vulgaris, S. aureus and S. epidermis.     

Multi-residue method for detecting coccidiostats at carry-over level in feed by HPLC–MS/MS

A multi-residue HPLC–ESI–MS/MS method has been developed for the simultaneous extraction, detection and confirmation of the 11 coccidiostats referenced by Regulation 2009/8/EC (lasalocid sodium, narasin, salinomycin sodium, monensin sodium, semduramicin sodium, maduramicin ammonium alpha, robenidine hydrochloride, decoquinate, halofuginone hydrobromide, nicarbazin, and diclazuril) in feedstuffs at carry-over level. The sensitivity of the method allows quantification and confirmation for all coccidiostats below target concentration. The method was in-house validated and meets all criteria of European legislation (2002/657/EC). The precision of the method was determined under repeatability and within-laboratory reproducibility conditions; RSD_r and RSD_R were below the maximum permitted values for every tested concentration. The specificity was checked by analysing representative blank samples and blank samples fortified with potentially interfering substances (benzimidazoles, corticosteroides, triphenylmethane dyes, quinolones, nitrofurans, nitroimidazoles, phenicols); no interference were found. Concerning quantification, a quadratic regression model was fitted to every calibration curve with a regression coefficient r ² above 0.99 on each data set. Finally, the expanded uncertainty U was calculated with data obtained within the laboratory while applying the method during validation and in routine tests.     

Contamination by moulds of grape berries in Slovakia

This paper describes the first map, albeit partial, of toxigenic fungi re-isolated from grape berries collected in three out of the six most important Slovakia winemaking areas in two different periods of the harvest year 2008. Low temperatures and high relative humidity during July 2008 favoured the development of grape fungal diseases that cause rots such as Plasmopara, Uncinula, Botrytis, Metasphaeria, Elsinoë, and Saccharomycetes. In the analysed samples, the following genera of toxigenic fungi were identified in the range of 1–4%: Aspergillus, Alternaria, Cladosporium, Epicoccum, Fusarium, Penicillium, Rhizopus, Ulocladium, and Trichoderma Trichothecium, while the genera Aspergillus, Alternaria, Fusarium, and Penicillium were in the range 11–29%. A. niger, A. carbonarius, some strains of A. carbonarius–with ‘crystals’ and strains of A. uvarum–uniseriate were identified; these species are considered ochratoxigenic (able to produce variable amounts of toxins). In addition, a non-ochratoxigenic strain of A. ibericus and a Fusarium strain able to biosynthesize small amount of fumonisins, beauvericin, and enniatins were identified. P. expansum, able to produce citrinin, represents 29.7%, of the Penicillium genus together with P. verrucosum, P. glabrum, P. citrinum, and P. crustosum. An analysis for the identification and quantification of the main toxins: ochratoxin A, fumonisins, beauvericin, enniatins, and fusaproliferin was performed on grape samples; it was consistent with the results of the mycological analysis. Toxigenic fungi should be checked throughout the years and their occurrence compared with all environmental factors to avoid health risks.