基于近红外光谱的五味子提取过程在线检测方法研究     

仲怿  潘万芳  朱捷强  范骁辉  康立源  李正 《勤云标准版测试》2015,(4):357-356

目的 利用近红外(NIR)光谱法,建立定量模型,实现五味子提取过程中关键指标的快速检测。方法 在线采集五味子提取液的近红外光谱,以高效液相色谱法和差重法获取参照,采用最小二乘回归法(PLSR)分别建立五味子醇甲、果糖、葡萄糖和可溶性固形物的定量模型。结果 定量模型的校正集相关系数R、校正均方根误差RMSEC、预测均方根误差RMSEP分别为：五味子醇甲0.99792、1.41、8.76,果糖0.99246、0.0919、0.333,葡萄糖0.99371、0.0954、0.448,可溶性固形物0.98723、3.07、11.2。结论 该方法快速、便捷,结果准确,适用于五味子提取过程的快速检测。  相似文献   

坛紫菜天然红色变异体的分离与特性分析          下载免费PDF全文

侯同玉  严兴洪 《上海海洋大学学报》2011,20(4):504-509

在坛紫菜栽培群体中发现一棵红色块与野生色块相嵌的颜色变异叶状体,在实验室进行红色藻块的体细胞再生克隆培养,获得了纯红色变异体。与野生型相比,红色变异体在叶状体的形态、颜色、生长速度、成熟、藻胆蛋白及叶绿素含量等方面均存在着明显的差异。红色变异体的颜色呈铁锈红色,体形宽大,生长速度明显快于野生型,培养400多天仍不成熟。与野生型相比,它的叶状体活体吸收光谱除各吸收峰的峰值有变化外,第4个吸收峰的峰顶(藻蓝蛋白的吸收峰)向短波方向移动了约3 nm,表明其藻红蛋白的结构有可能发生了改变。另外,它的藻红蛋白(PE)和叶绿素a的含量均显著增加,但藻蓝蛋白(PC)的含量有所下降,使得PE/Chl. a和PC/Chl. a的比值较高, 但PE/PC比值较低。培养400 d的红色变异体的体细胞再生体中,正常叶状体和畸形叶状体的百分数分别为78.49%和19.81%,根丝细胞苗占1.7%,未见细胞团出现,说明该变异体的不成熟是由叶状体的细胞分化严重延缓所致。  相似文献   

基于可见/近红外反射光谱的梨树叶片钾含量的快速测定研究   总被引：1，自引：0，他引：1  

赵化兵  王洁  董彩霞  徐阳春 《土壤》2014,46(2):256-261

利用可见/近红外反射光谱定量分析技术对梨树鲜叶钾素含量进行快速测定研究。对150个梨树叶片样本进行光谱扫描,其中120个做建模集,30个做验证集。通过对样品的可见/近红外光谱进行多种预处理,并建立钾素预测模型,探讨了可见/近红外光谱数据预处理对预测精度的影响。结果表明,通过原始光谱与S-G(3)平滑相结合的预处理方法,用17个主成分建立的偏最小二乘法模型最好,其交叉验证集和预测集模型的决定系数(R2)分别为0.722 7和0.679 1,交叉验证均方根误差(RMSECV)为1.171,预测的平均相对误差为6.81%,能高效、快速地预测梨树叶片钾素含量,为梨树钾素快速测定提供了新的手段。  相似文献   

Multifractal and joint multifractal analysis of soil micronutrients extracted by two methods along a transect in a coarse textured soil     

Ênio Farias de França e Silva  Aitor García-Tomillo  Diego Henrique Silva de Souza  Eva Vidal-Vázquez  Glécio Machado Siqueira  Daniel da Costa Dantas  Antonio Paz-González 《European Journal of Soil Science》2021,72(2):608-622

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联合Terra/Aqua MODIS多角度多光谱数据反演冬小麦叶面积指数   总被引：1，自引：1，他引：0  

何维  杨华 《农业工程学报》2013,29(4):204-212

Terra与Aqua双星搭载的MODIS传感器可实现每日上下午分别对同一地点观测一次,并且由于卫星轨道漂移形成累积连续多天的多角度观测特点,加上多通道的光谱响应,极大地丰富了地表目标的观测信息,为LAI等地表参数的实时准确反演提供了可能。该文利用MODIS双星高质量的连续多天的多波段地表反射率数据,结合PROSAIL(PROSPECT+SAIL,properties spectra+scattering by arbitrarily inclined leaves)模型和查找表方法反演冬小麦LAI,并与MODIS LAI产品及野外采样点实测LAI对比,结果表明,联合双星高质量的多角度多波段数据能够较准确反演冬小麦LAI,其反演结果无论从空间分布还是时序变化特征来讲,较MODIS LAI产品更符合实际情况,也更接近地面实测值。该文的研究为充分利用MODIS数据的角度和光谱信息反演小麦等农作物的LAI提供了一定的借鉴。  相似文献   

基于杠杆率校正的PLS-DA法对正半岩武夷岩茶的识别研究   总被引：3，自引：2，他引：1  

周健  成浩  王丽鸳  薛凤仁  何孝延  徐锦斌  贺巍 《茶叶科学》2009,29(1)

武夷岩茶属于闽北乌龙茶,是福建省的特有茶类,也是我国传统名茶中的精品,尤其以武夷中心地带所产的正岩茶品质最佳。本文采用近红外光谱技术,利用杠杆率校正(leverage correction)结合偏最小二乘法(Partial least Squares Discriminant Analysis,PLS-DA)的分析方法,进行了武夷岩茶中的正岩茶与半岩茶的分类识别研究。结果表明不仅定标集42个样本的识别正确率为100%,对于未参与模型建立的验证集20个样本的识别正确率也达到了100%。初步证明了利用近红外技术结合PLS-DA分析方法对正岩茶与半岩茶进行分类识别的可行性。  相似文献   

Feeding quality assessment of fresh maize stover by means of near-infrared spectroscopy with a new sample presentation unit     

J. M. Montes    V. Mirdita    K. Prasad    M. Blummel    A. E. Melchinger 《Plant Breeding》2008,127(2):214-216

Stover quality traits are important in breeding programmes of maize cultivars. However, conventional procedures for evaluation of stover quality are expensive and thus limit the full exploitation of the available genetic variability. Our objective was to assess the potential of near‐infrared spectroscopy (NIRS) with a new sample presentation unit to determine feeding quality of maize stover. The plant material comprised maize inbreds and hybrids. The sample presentation unit was equipped with a near‐infrared diode‐array spectrometer. Coefficient of determination in cross‐validation ranged between 0.77 and 0.94 for contents of dry matter, nitrogen, neutral detergent fibre and in vitro fermentability expressed as gas volume after 24h incubation time, but it was lower for ash content. It was concluded that NIRS with the new sample presentation unit was less accurate than laboratory NIRS to predict the standard reference methods. However, the new sample presentation unit might be used as a fast and efficient technique to perform large screenings of maize stover accessions in breeding programmes.  相似文献   

新课程背景下政治教师的教学反思     

肖奕雯 《湖南农机》2008,(4):67-69

长期以来,政治课教学在一定程度上存在着失效和失信的问题,教学反思是政治教师成长中的重要条件,能够使政治教师成为教学中的自觉者、促进知识结构完善的学习者、促进教育观念更新的变革者。文章在分析新课程背景下政治教师教学反恩的必要性的基础上,探讨了教学反思的内容及策略。  相似文献   

主/从机器人系统设计与双向伺服控制   总被引：1，自引：1，他引：0  

陈铁华  赵丁选  张祝新 《农业机械学报》2008,39(12):141-145

建立了主／从异构式机器人力反馈遥操作控制系统。主操作系统采用2个2-DOF操作手,分别采用伺服阀控制液压马达获得2个解耦的旋转自由度。用力信息对伺服阀进行控制以驱动主操作手运动,解决主手操纵力不能直接驱动主操作手液压马达的问题。从机器人为4-DOF串联关节型四自由度机器人,采用比例方向阀控制。分别采用力反射伺服型和力对称型双向伺服控制策略,对主／从机器人系统进行遥操作力反馈双向伺服控制实验研究。验证了本设计的主操作手结构的合理性,力对称型双向伺服控制策略具有较好的控制性能。  相似文献   

Structural changes in lignin of tropical woods during digestion by termite, <Emphasis Type="Italic">Cryptotermes brevis</Emphasis>     

Kyoko S. Katsumata  Zhenfu Jin  Keko Hori  Kenji Iiyama 《Journal of Wood Science》2007,53(5):419-426

Wood samples of apitong (Dipterocarpus grandiflorua) and ilang-ilang (Ilang-Ilang C. dadloyi) and feces of termites [Cryptotermes brevis (Walker)] fed on these woods were collected from University of the Philippines, Los Baňos. Lignin of each sample was isolated by Björkman’s procedure. There was no significant difference in ¹H nuclear magnetic resonance (NMR) spectra or in the methoxyl content between Björkman lignins from original woods and termite feces. Differences were detected in the contents of aliphatic and unconjugated phenolic hydroxyl groups, suggesting minor structural changes of lignin during digestion by termites. In addition, the ratio of syringyl to guaiacyl nuclei of Björkman lignin from termite feces determined by ¹H NMR spectra was higher than those from the original woods. The molar ratio of syringyl to guaiacyl nuclei of termite feces was higher than those from the original woods as determined by alkaline nitrobenzene oxidation. These results suggest that the structural changes of lignin in the termite gut are due to the insignificant formation of C-C linkages in guaiacyl nuclei. It was concluded that there were minor changes in the structural features of lignin under mostly anaerobic conditions, in contrast to the significant changes that occur through biological modification under aerobic conditions.  相似文献