单波长色散X射线分析仪分析机理及在油品升级中的应用

对比了目前国际上比较常用的几种总硫分析方法的分析机理、适用范围以及优缺点,针对汽油吸附脱硫装置的特点,要求总硫分析仪具有较大的测定范围、较低的硫限制含量检测值、良好的线性度、迅速的响应时间、优良的重复性、少量的维护量.通过分析比较最终选用单波长色散X射线荧光型总硫分析仪做为其原料和产品的在线总硫含量检测手段,文章对其定性和定量的分析机理、结构组成、检测特点、样品预处理系统、取样回样的方式、自动标定的方式及其在工程应用中需要注意的事项作了叙述.     

原油中在线总硫分析仪的选用

原油作为成品油的生产原料其总硫含量需要严格监控.为了监测直供常减压的原油长输线中总硫的含量,需设一套在线总硫分析仪.简要介绍了库仑滴定法、醋酸铅法、化学发光法、紫外荧光法等4种硫含量的检测原理,重点介绍了X射线荧光光谱分析法.针对在线检测要求及原油中含蜡和固体杂质,试样一般温度高,压力大,较黏稠,雾化比较困难等介质特性...     

石油产品中硫含量测定方法适用性研究

本文通过分析我国石油产品标准中规定的硫含量分析方法，明确各种方法的适用性，并对常用的能量色散X射线荧光光谱法、电量法、单波长色散X射线荧光光谱法和紫外荧光法四种测定方法的重复性进行试验，提出石油产品中硫含量检测的选择方法，为不同石油产品的硫含量测定方法的选择提供参考依据，在实际工作中提高分析的准确度。     

X射线荧光光谱测定灯用煤油中的微量硫

本法利用波长色散X射线荧光光谱仪测定灯用煤油中的硫 ,测量精密度较好 ,加标回收率为 90 .4 %～ 10 8.9% ,检测限 (LLD)为 0 .6× 10 - 6 (ws)。     

新型的金属定量仪

定性或定量测定石油产品、污垢、淤渣中的各种金属,历来是采用发射光谱、原子吸收光谱、化学分析等方法。最近,国外发展了一种能量色散型荧光 X 射线分析仪,已开始商品化。这种仪器比过去的波长色散型荧光 X 射线分析仪前进了一步。它不需要以往那种测角分光晶体,而是采用硅半导体鉴定器和多路分析器,可在很短     

轻质燃料油硫含量分析方法评价

对轻质燃料油硫含量分析所使用的紫外荧光法、单波长色散X射线荧光光谱法、电量法3种方法进行评价,就其影响因素及3种分析方法的一致性进行比对分析。结果表明,3种分析方法测定低硫含量样品分析结果基本一致,重复性好、准确度高。同时对不同分析方法的优缺点进行了比较,在硫含量分析方法的选择时,可根据馏分情况、硫含量及实验室设备情况等因素来选择准确、高效、经济的检测方法。     

汽油中加入苯胺对硫含量检测结果的干扰及消除方法

针对汽油中加入苯胺对硫含量检测结果造成干扰的问题，分别采用《SH/T 0689-2000轻质烃及发动机燃料和其他油品的总硫含量测定法(紫外荧光法)》和《NB/SH/T 0842-2017轻质液体燃料中硫含量的测定单波长色散X射线荧光光谱法》进行试验，在三种不同硫含量的汽油样品中加入苯胺，用单波长色散X射线荧光光谱法检测硫含量不受干扰；用紫外荧光法检测硫含量，在氮含量大于100 g/L时，均会不同程度对硫含量检测产生干扰。可采取在硫含量标准物质中加入氮含量标准物质，按照试验方法制作标准曲线后对样品进行检测，或采取加装臭氧激发装置的方法解决干扰，使用该方法时应采取相应措施避免SO₂,转化为SO₃。     

单波长荧光光谱法测定原油中的盐含量

针对电量法分析盐含量的繁琐及重复性差的问题,开发采用单波长荧光光谱法分析原油中的盐含量,用单波长色散X射线荧光光谱仪检测原油中的无机氯,标准曲线法定量,再通过计算得到原油中盐含量(以NaCl计),回收率为94.28%～99.51%,6次重复测定的相对标准偏差小于8%,数据定量相对准确可靠,优于电量法的重复性,能满足生产的检测需求。     

SOLAⅡ总硫分析仪在催化汽油加氢脱硫装置中的应用

SOLAⅡ总硫分析仪主要用于检测燃料油或天然气等组分中的总硫质量分数、工艺过程中微量硫监测、火炬气排放总硫监测等。其紫外荧光分析方法符合ASTM以及国内石油化工行业标准规定的总硫分析方法,分析数据具有很好的平稳性,能够及时、可靠地跟踪过程的变化,准确地反映过程的实际情况,消除了人工取样可能产生的安全隐患,也节省了操作运行成本及工人的劳动强度。简述了SOLAⅡ总硫分析仪在实际应用中的注意事项。     

X射线荧光岩屑录井仪器

由光谱分析的一般检测原理入手,介绍X射线荧光岩屑分析仪器的基本原理及仪器构成。分析了波长色散型和能量色散型两类仪器的优缺点,简介了XRF仪器结构、特点、技术指标、检测电路和采集软件功能。针对XRF分析仪器的特殊结构阐述了X射线荧光岩屑分析的实践依据。通过室内测试和现场45口井的验证应用,证实该仪器的检测精度、重复性和稳定性等均达到了设计指标要求,为岩屑录井提供了全新手段,丰富了录井资料,为地层的解释评价创造了有利条件。     

往复式空气压缩机常见故障及处理

介绍了往复式空气压缩机运行中常见故障,分析了产生故障的主要原因,提出了处理方法。     

Clothianidin dissipation in tomato and soil, and distribution in tomato peel and flesh

Clothianidin, a new neonicotinoid insecticide, was systematically evaluated. An analytical method using gas chromatography with electron capture detection was developed. Recoveries were between 92% and 102%, with relative standard deviations from 3% to 5% at three fortified levels. The decrease of clothianidin in tomato and soil samples under field conditions at Beijing, Shandong, and Anhui were determined. The dissipation rates of clothianidin fit first-order kinetics. Its half-lives ranged from 6.7 to 12.7 days in soil, and 7.0 to 11.9 days in tomato. On the suggested pre-harvest interval of 7 days, the distribution of clothianidin in tomato peel and flesh was studied. Most residues were found on the peel. Hence, removing the tomato peel before consumption is advisable. The stability of clothianidin fortified at 0.3 or 3 mg/kg in frozen green and red ripe tomatoes was also determined. The half-life mainly depended on the spiked levels of this pesticide.     

中国致密砂岩气及在勘探开发上的重要意义

致密砂岩气藏系指聚集工业天然气的致密砂岩场晕或圈闭,根据其储集层特征、储量大小及所处区域构造位置高低,可将致密砂岩气藏分为两类:"连续型"致密砂岩气藏和"圈闭型"致密砂岩气藏,前者通常位于构造低部位,圈闭界限模糊,无统一气水界面,往往气水倒置,储源一体或近源;后者位于圈闭高处,上气下水,储量规模较小但产量相对较高。中国致密砂岩气都是煤成气,组分以烷烃气(C1 4)为主,甲烷含量最高,烷烃气具正碳同位素系列;非烃气(主要是CO2和N2)含量低。截至2010年底,中国致密砂岩气的储量和年产量分别占全国天然气储量和产量的39.2%和24.6%,预计将来比例还会提高。与页岩气、煤层气等非常规气相比,中国近期在非常规气勘探开发中应以致密砂岩气为先。     

Aflatoxins and fumonisins in rice and maize staple cereals in Northern Vietnam and dietary exposure in different ethnic groups

Mycotoxins in food are increasingly a food safety hazard concern in particular in developing countries. This study was performed to determine the occurrence and determinants of aflatoxin and fumonisin contamination in rice and maize and to assess health risks through dietary intake exposure among ethnic minority groups in northern Vietnam. A total of 111 rice and 102 maize samples, were tested for occurrence of fungi and mycotoxins, i.e. aflatoxins (AF’s) and fuminisin B (FB). Results showed that 107 (96.4%) rice and 84 (82.4%) maize samples were contaminated by fungi. Aspergillus flavus was found in 68 (61.3%) rice and 30 (29.4%) maize samples, Aspergilus parasiticus in 40 (36.0%) rice and 27 (26.7%) maize samples. AF’s - were detected in 27 rice (24.3%) and 27 maize samples (26.4%) at minimum and maximum levels in rice of 2.06 and 77.8 ng/g and 20.5 and 110 ng/g in maize, respectively. Nine (8.1%) rice and 24 (23.5%) maize samples contained FB at ranges of 2.3–624 ng/g in rice and 5.6–89.8 ng/g in maize. Data collected through interviews and observations in households showed that type of crop, storage duration and presence of fungi, particularly mycotoxigenic fungi were important risk factors for AF’s and FB contamination. Based on daily food consumption data, the estimated average exposure dose of aflatoxin B₁(AFB₁) from rice was 21.7 ng/kg bw/day for adults and 33.7 ng/kg bw/day for children. For FB, the rice based average exposure amounted to 536 ng/kg bw/day for adults and 1019 ng/kg bw/day for children. The calculated excess risk of liver cancer incidence by ingestion of cereals containing AFB₁ was 1.5 per 100,000 adults and 2.3 per 100,000 children per year. The average intake of FB was calculated to be lower than the tolerable diet intake (TDI). Our findings highlight that rice and maize are contaminated with mycotoxins at levels representing actual health hazards for the ethnic minority groups consuming these stable cereals. Proper drying and storage conditions in households are likely to reduce the mycotoxin contamination.     

Aflatoxin M1 in raw and UHT cow milk collected in Bosnia and Herzegovina and Croatia

Aflatoxin M1 (AFM1) concentrations were determined in raw and UHT cow milk samples collected in different regions of Bosnia and Herzegovina and Croatia during the autumn months of 2014. The mean AFM1 levels in the raw milk samples were (ng/kg): 6.22 in Bosnia and Herzegovina, 5.65 in Croatia. In all except one milk sample, AMF1 levels were below the LOQ value of 34.2 ng/kg (ELISA method). In four milk samples, AFM1 concentrations exceeded the EU MRL of 50 ng/kg. Samples were subjected to LC-MS/MS analysis which confirmed elevated values determined by ELISA. Elevated levels were in the range 56.6–132.6 ng/kg. Two positive milk samples from Bosnia and Herzegovina originated from Una Sana Canton, two from Croatia from eastern Croatia. The highest AFM1 levels of 132.6 ng/kg was measured in milk from eastern Croatia. In 214 samples of processed UHT milk from Bosnia and Herzegovina and Croatia, AFM1 ranged from 2.29 ng/kg to 21.4 ng/kg, all below the LOQ value. AFM1 exceeded the EU MRL value in only 0.62% of milk samples, indicating the sporadic use of contaminated feedstuff at farms in both countries.     

改进中加强 创新中发展——改革开放30年企业思想政治工作的实践与探索

改革开放30年来，企业思想政治工作随着形势的不断变化，曾经面临着诸多新问题。企业思想政治工作正是在解决这些问题的实践中不断探索，创新思路和方法，提升效果和水平，成为企业改革、发展、进步的动力源泉。     

Aflatoxins and ochratoxin A in dried chestnuts and chestnut flour produced in Italy

The occurrence of aflatoxins and ochratoxin A in chestnut products made in Italy was surveyed. Thirty-seven samples of chestnut flour and fourteen of dried chestnuts were collected from retail outlets located in northern Italy. After extraction and purification through an immunoaffinity column, aflatoxins and ochratoxin A were analysed using both HPLC-FLD and HPLC-MS/MS. The mycotoxin contamination found in this survey was widespread and remarkable. As regards aflatoxins, the incidence of aflatoxin B₁ was 62.2 and 21.4% in chestnut flour and dried chestnuts, respectively; in the same products, the percentage of samples exceeding the value of 2.0 μg kg⁻¹ for aflatoxin B₁ (maximum limit fixed by EC Regulation 165/2010 in dried fruits) was 24.3% and 7.1%. A widespread and high incidence of AFG₁ was also found (40.5%). The maximum values for aflatoxin B₁ and total aflatoxins were 67.88 and 188.78 μg kg⁻¹, respectively (chestnut flour sample). Ochratoxin A occurred in all samples, showing very high values (mean 12.38 and 13.63 μg kg⁻¹ for chestnut flour and dried chestnuts, respectively); the percentages of samples exceeding the limit of 10 μg kg⁻¹ (EU limits for dried vine fruit) were 64.9 and 42.8% for chestnut flour and dried chestnuts, respectively. The maximum value was 65.84 μg kg⁻¹ (dried chestnut sample).     

Aflatoxigenic fungi and aflatoxins occurrence in sultanas and dried figs commercialized in Brazil

The presence of aflatoxins, Aspergillus flavus and Aspergillus parasiticus in dried fruits was investigated. A total of 62 dried fruit samples were analyzed (24 black sultanas, 19 white sultanas and 19 dried figs). A total of 10 A. flavus isolates were found, nine in one white sultana sample (corresponding to 18% infection) and one isolate in dried figs (2%), and all of them were aflatoxin B₁ and B₂ producers. A. parasiticus was not found. Aflatoxins were detected in 3 of 19 (16%) white sultana samples analyzed and, the limits were not higher than 2.0 μg/kg. In dried figs 11 of 19 (58%) samples were contaminated with aflatoxins and, with exception of one sample that was contaminated with 1500 μg/kg of B₁ aflatoxin, the others had less than 2.0 μg/kg. Neither aflatoxigenic or aflatoxins contaminated black sultanas.