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1.
杨亭榆 《绿色科技》2021,(6):245-249,280
黄水是白酒在固态发酵过程的副产物,含有大量发酵产物,黄水的成分一定程度反映了固态发酵的信息。基于白酒固态发酵只能在线检测温度这一现状,设计了针对白酒副产物黄水的一种传感器阵列检测装置,用于检测黄水的总酸和残余葡萄糖。该传感器阵列由电导率传感器、pH传感器和氧化还原传感器构成。采用主成份分析、判别函数分析印证了传感器数据对不同样品的区分作用,再采用多元线性回归对黄水样品建立了预测模型,结果显示:该传感器阵列装置对黄水的总酸和残余葡萄糖的预测偏差分别为0.39和0.45。  相似文献   
2.
Meta‐analysis of marine biological resources can elucidate general trends and patterns to inform scientists and improve management. Crustacean stocks are indispensable for European and global fisheries; however, studies of their aggregate development have been rare and confined to smaller spatial and temporal scales compared to fish stocks. Here, we study the aggregate development of 63 NE Atlantic and Mediterranean crustacean stocks of six species (Nephrops norvegicus, Pandalus borealis, Parapenaeus longirostris, Aristeus antennatus, Aristaeomorpha foliacea and Squilla mantis) in 1990–2013 using biomass index data from official stock assessments. We implemented a dynamic factor analysis (DFA) to identify common underlying trends in biomass indices and investigate the correlation with the North Atlantic Oscillation (NAO) index. The analysis revealed increasing and decreasing trends in the northern and southern NE Atlantic, respectively, and stable or slowly increasing trends in the Mediterranean, which were not related to NAO. A separate meta‐analysis of the fishing mortality (F) and biomass (B) of 39 analytically assessed crustacean stocks was also carried out to explore their development relative to MSY. NE Atlantic crustacean stocks have been exploited on average close to FMSY and remained well above BMSY in 1995–2013, while Mediterranean stocks have been exploited 2–4 times above FMSY in 2002–2012. Aggregate trends of European crustacean stocks are somewhat opposite to trends of fish stocks, suggesting possible cascading effects. This study highlights the two‐speed fisheries management performance in the northern and southern European seas, despite most stocks being managed in the context of the European Union's Common Fisheries Policy.  相似文献   
3.
我国流行的猪繁殖与呼吸综合征病毒(Porcine reproductive and respiratory syndrome virus, PRRSV)包括美洲型经典毒株和变异株。本研究应用RT—PCR、直接免疫荧光( direct immunofluorescence asay, DFA )及病毒分离3种检测方法对99份不同类型的猪繁殖与呼吸综合征临床疑似病料和人工感染病料进行检测。结果显示,RT—PCR检测试剂盒敏感性最高,DFA鉴别诊断试剂盒次之,病毒分离最差。DFA与病毒分离、RT—PCR的总符合率分别为92%和85.5%。RT—PCR灵敏性高,可作为PRRSV鉴别诊断的首选方法;DFA鉴别诊断法所需时间较短、特异性好,但需要一定的操作经验;病毒分离敏感性低、操作繁琐,阳性分离需要其它方法验证,不适合于PRRSV的鉴别诊断。  相似文献   
4.
利用电子鼻系统对不同干燥方式的糯米香茶茶汤风味进行分析检测,通过对传感器响应信号的处理及选取适当的模式识别方法,取得了较好的区分效果。结果表明,电子鼻能够区分不同干燥方式(恒温鼓风干燥、真空冷冻干燥、真空干燥)的糯米香茶茶汤风味。在模式识别中,判别因子分析法(DFA)的识别结果优于主成分分析法(PCA)。  相似文献   
5.
The performance of electronic nose (E-nose) for Chinese Cymbidium scent profiling has been evaluated. Changes in scent profiles of two Cymbidium ensifolium cultivars have been monitored at different flowering stages (initial flowering, full flowering, and terminal flowering) and different times combined with two gas collecting devices. Samples were collected by static headspace (SHS) method. How E-nose can be used for pattern recognition and for studying the releasing of flower scent were proposed. Data obtained were subjected to principal component analysis (PCA) and discriminant function analysis (DFA). PCA was performed on the initially instrumental data to explore the structure of each data set and such result showed that the sensory data contained information related to the cultivar and to time spots. DFA was performed to improve the results, leading to clear separations between the sample groups. Gas collecting device did not seriously affect the result of PCA and DFA. Relative aroma intensity (RAI) was proposed as an alternative concept to compare scent intensity between samples on different time points. These results demonstrate the potential application of the E-nose to evaluate the scent profile of flower.  相似文献   
6.
【目的】文峪河是山西省吕梁地区的重要水源地之一,研究其径流量变化可为整个吕梁地区的水安全保障体系建设和区域社会经济规划与产业布局提供决策支持。【方法】应用Hilbert-Huang变换(HHT)方法、非趋势波动分析方法(DFA)以及BP神经网络预测方法,对文峪河中长期天然径流序列的周期变化特征、分形特征进行非线性分析,探讨了影响径流形成的降水、气温等气候要素对文峪河径流演变的影响,并进一步分析了厄尔尼诺现象、太阳黑子活动与文峪河径流变换的响应关系。以EMD分解结果和标度不变性为依据,对径流未来的演化发展趋势进行预测,并分析了未来流域水安全的态势。【结果】文峪河径流序列存在准2年、准4年、6~7年和13~14年的周期变化规律;文峪河径流变化受气候要素影响强烈,与厄尔尼诺现象、太阳黑子数存在良好的响应关系;文峪河年径流序列具有分形结构特征和趋势增强特征。【结论】未来文峪河年径流存在一个持续的缩减趋势,2050年文峪河水库坝址处的径流量可能将缩减至0.5亿m3左右,比坝址处多年平均径流量减少近65%,流域水安全局势堪忧。  相似文献   
7.
刘道格  岳士刚  程慧祥 《安徽农业科学》2011,39(35):21965-21967,22041
运用消除趋势波动分析法(DFA),分析了上海市近8年PM10污染指数序列数据,并进行了时间序列的长程相关性分析,有效消除了数据中的噪声和非平稳信息影响,得到了定量描述PM10污染指数的长期演变行为的参数,即标度指数α。根据标度指数α的变化特性,探讨了PM10污染指数的长程幂律相关及其存在的时间尺度等问题。结果表明,该方法是可行的,从2003年7月1日开始,上海市的PM10污染指数变化的总体趋势是降低的,说明近8年来,上海市PM10污染情况得到了改善。该研究结果对于认识上海市城市大气环境质量变化过程和科学制定环保决策具有重要意义。  相似文献   
8.
IBDV强毒株与弱毒株对SPF鸡侵染过程的研究   总被引:3,自引:0,他引:3  
用DIG标记PS19探针和异硫氰酸荧光素标记的鸡抗IBDV IgG,对人工接种IBDV强毒株Hrb和弱毒细胞适应株Ts后不同时间段的法氏囊、盲肠扁桃体、脾、肾、肝、胸腺、大腿及胸部肌肉的石蜡切片分别进行原位杂交和荧光抗体检测。同时将各时间段每种组织的石蜡切片进行HE染色以观察组织破坏情况。结果发现,用原位杂交和荧光抗体两种方法首先分别于接种Hrb后8h和16h在法氏囊中检测到IBDV的阳性信号,然后依次是盲肠扁桃体、脾、肾、肝、胸腺。侵害程度以法氏囊最重。实验结果表明:Hrb毒株在组织中复制速度快,并迅速在SPF鸡体内传播。Ts毒株侵染较轻,对器官组织无损伤。  相似文献   
9.
对欧盟碳市场两个主要交易品种EUA和CER进行了高阶DFA分析,结果发现:不同阶数的DFA分析得到的标度指数不同,CER的标度指数的差异程度较大,认为CER的价格波动性更加剧烈。另外,传统DFA和滑动窗DFA得到的实证结果相同,EUA和CER研究的第一阶段的标度指数均大于0.5,具有长程相关性;第二阶段的值均小于0.5,具有状态反持续性。总体来看,EUA和CER的收益率序列具有分形市场中的状态持续性,也就是说,欧盟碳市场不是有效市场,而是有偏的随机游走。  相似文献   
10.
A progressive classification of a marsh and forest system using Landsat Thematic Mapper (TM), color infrared (CIR) photograph, and ERS-1 synthetic aperture radar (SAR) data improved classification accuracy when compared to classification using solely TM reflective band data. The classification resulted in a detailed identification of differences within a nearly monotypic black needlerush marsh. Accuracy percentages of these classes were surprisingly high given the complexities of classification. The detailed classification resulted in a more accurate portrayal of the marsh transgressive sequence than was obtainable with TM data alone. Individual sensor contribution to the improved classification was compared to that using only the six reflective TM bands. Individually, the green reflective CIR and SAR data identified broad categories of water, marsh, and forest. In combination with TM, SAR and the green CIR band each improved overall accuracy by about 3% and 15% respectively. The SAR data improved the TM classification accuracy mostly in the marsh classes. The green CIR data also improved the marsh classification accuracy and accuracies in some water classes. The final combination of all sensor data improved almost all class accuracies from 2% to 70% with an overall improvement of about 20% over TM data alone. Not only was the identification of vegetation types improved, but the spatial detail of the classification approached 10 m in some areas.  相似文献   
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