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1.
《Food Control》2015
The aim of the study was to investigate annual and regional differences in the level of aflatoxin B1 (AFB1) in grains and dairy cattle feed. Maize (n = 972), wheat (n = 201), barley (n = 147), oat (n = 136), grain mixtures (n = 168), and dairy cattle feed (n = 325) were sampled from 2009 to 2013 on different farms and in different farm factories situated in four Croatian regions. The samples were analysed for AFB1 using the validated ELISA immunoassay. AFB1 was determined in 16.4% of all investigated samples, among which maize was proven to be the most contaminated, with 21.7% of the samples recovered during 2013 harbouring AFB1 in concentrations over the permissible ones. Levels higher than permitted were observed in 17.9% and 12.3% of grain mixtures and dairy cattle feed, respectively, whereas concentrations of AFB1 determined in other crops throughout the investigated period met the stipulated requirements. The results revealed the AFB1 occurrence to be significantly (p < 0.05) dependent on the cultivation region, with the highest levels generally found in maize harvested in 2013 and consequently in grain mixtures and cattle feed that can most likely be associated with climatic conditions as the most critical factor for mould formation, and thus also AFB1 production. 相似文献
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The morphology of the photoactive layer critically affects the performance of the bulk heterojunction polymer solar cells (PSCs). To control the morphology, we introduced a hydrophobic fluoropolymer polyvinylidene fluoride (PVDF) as nonvolatile additive into the P3HT:PCBM active layer. The effect of PVDF on the surface and the bulk morphology were investigated by atomic force microscope and transmission electron microscopy, respectively. Through the repulsive interactions between the hydrophilic PCBM and the hydrophobic PVDF, much more uniform phase separation with good P3HT crystallinity is formed within the active layer, resulting enhanced light harvesting and improved photovoltaic performance in conventional devices. The PCE of the conventional device can improve from 2.40% to 3.07% with PVDF additive. The PVDF distribution within the active layer was investigated by secondary ion mass spectroscopy, confirming a bottom distribution of PVDF. Therefore, inverted device structure was designed, and the PCE can improve from 2.81% to 3.45% with PVDF additive. Our findings suggest that PVDF is a promising nonvolatile processing additive for high performance polymer solar cells. 相似文献
3.
给水管网计算中的数据转换方法 总被引:3,自引:0,他引:3
在给水管网计算中,通过建立环-管段矩阵、环-节点矩阵以及输入节点流量、节点坐标等少量数据,通过计算和数据转换,便可求得经济管径、管段设计流量、节点水压值、水厂供水量、管网造价、年费用折算值等。采用该方法进行管网计算,可以减少40%~70%的计算时间。 相似文献
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含氯取代基的聚间苯二甲酰间苯二胺的合成与表征 总被引:7,自引:0,他引:7
以 2 ,5 -二氯对苯二甲酰氯作为第三单体 ,将其与间苯二甲酰氯、间苯二胺在N ,N -二甲基乙酰胺中进行低温溶液共缩聚反应 ,合成了含氯取代基的聚间苯二甲酰间苯二胺。研究了单体摩尔浓度、反应初始温度、叔胺添加剂种类、第三单体用量等对共聚物相对分子质量的影响 ,并用红外光谱、热重分析等方法对共聚物进行了表征。 相似文献
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添加剂组成对通用内燃机油性能的影响 总被引:1,自引:0,他引:1
通过相关模拟试验,分析研究了添加剂组成对通用内燃机油的抗磨性能,抗氧化性能以及清净分散性能的影响。 相似文献
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Industry widely uses rotary valves and blow tanks for the pneumatic conveying of products, each having their pros and cons depending on the specific application. This article shows the differing results obtained when low-velocity conveying a product through a common pipeline using both a drop-through rotary valve and a bottom-discharge blow tank feeder. A number of issues arise in the rotary valve system, the main one being rotary valve air leakage. A blow tank system, on the other hand, does not leak, as it is an enclosed system. The experimental results show dramatic differences in product throughput. Further exploration leads to a novel modification being made to the rotary valve system in an attempt to increase its capacity. The result of this modification shows a slight increase in output tonnage, but still significantly less than that obtained from the blow tank. 相似文献