3个蕉类品种果实多酚氧化酶的特性研究

[目的]为控制3个蕉类品种多酚氧化酶（PPO）引起的酶促褐变提供理论依据。[方法]对3个蕉类品种果实PPO的最适pH与pH稳定性、最适温度与热稳定性以及化合物的影响进行了比较分析。[结果]威廉斯蕉、大蕉及粉蕉PPO最适pH分别为8.56、.5、6.5;pH稳定性范围都在pH 6.0～11.0;PPO最适温度分别是60、303、0℃;PPO的耐热性表现为威廉斯蕉PPO〉粉蕉PPO〉大蕉PPO;威廉斯蕉PPO活性的最佳抑制剂是盐酸-L-半胱氨酸,其次是抗坏血酸,再次是NaHSO3;大蕉、粉蕉PPO活性的最佳抑制剂都是抗坏血酸,其次是NaHSO3、盐酸-L-半胱氨酸。[结论]3个蕉类品种中威廉斯蕉PPO的耐热性最高,威廉斯蕉、大蕉及粉蕉PPO的化学抑制剂基本一致。     

科技特派员创业链的内涵、特征及培育策略

文章对科技特派员创业链的概念进行了阐述,分析了科技特派员创业链的具体内涵,描述了科技特派员创业链的运行特征,提出了加强管理、培育创业链主体、加大投入、金融支持等科技特派员创业链培育的若干策略。     

Automatic grading of Bi-colored apples by multispectral machine vision

In this paper we present a novel application work for grading of apple fruits by machine vision. Following precise segmentation of defects by minimal confusion with stem/calyx areas on multispectral images, statistical, textural and geometric features are extracted from the segmented area. Using these features, statistical and syntactical classifiers are trained for two- and multi-category grading of the fruits. Results showed that feature selection provided improved performance by retaining only the important features, and statistical classifiers outperformed their syntactical counterparts. Compared to the state-of-the-art, our two-category grading solution achieved better recognition rates (93.5% overall accuracy). In this work we further provided a more realistic multi-category grading solution, where different classification architectures are evaluated. Our observations showed that the single-classifier architecture is computationally less demanding, while the cascaded one is more accurate.     

Detection of contaminated hazelnuts and ground red chili pepper flakes by multispectral imaging

Mycotoxins are the toxic metabolites of certain filamentous fungi and have been demonstrated to cause various health problems in humans, including immunosuppression and cancer. Among them, the aflatoxins have received greater attention because they are potent carcinogens and are responsible for many human deaths per annum, mostly in non-industrialized countries. Various regulatory agencies have enforced limits on the concentrations of these toxins in foods and feeds involved in international commerce. Hyperspectral and multispectral imaging are becoming increasingly important for rapid and nondestructive testing for the presence of such contaminants. However, the high number of spectral bands needed may render such image acquisition systems too complex, expensive and slow. Moreover, they tend to generate overwhelming amount of data, making effective processing of this information in real time difficult. In this study, a two-dimensional local discriminant bases algorithm was developed to detect the location of the discriminative features in the multispectral data space. The algorithm identifies the optimal passband width and center frequencies of optical filters to be used for a multispectral imaging system. This was applied to a multispectral imaging system used to detect aflatoxin-contaminated hazelnut kernels and red chili peppers. Classification accuracies of 92.3% and 80% were achieved for aflatoxin-contaminated and uncontaminated hazelnuts and red chili peppers, respectively. The aflatoxin concentrations were decreased from 608 to 0.84 ppb for tested hazelnuts and from 38.26 to 22.85 ppb for red chili peppers by removal of the nuts/peppers that were classified as aflatoxin-contaminated. The algorithm was also used to classify fungal contaminated and uncontaminated hazelnut kernels, and an accuracy of 95.6% was achieved for this broader classification.     

海南休闲农业发展的模式及其保障措施初探

为了有效了解海南当前休闲农业发展现状,加快海南休闲农业资源整合升级,本文通过资源优势分析、产业分布和效益对比,在列举存在的六点存在问题基础上,提出海南发展城郊农家乐式旅游、村落乡镇旅游、热带田园农业休闲观光旅游、回归自然旅游、民俗风情旅游和科普及教育旅游等六大特色休闲农业模式,强调落实规划入手、政府支持、资源和技术整合及突出地方特色等五点保障措施是必要的。总结出海南在发展本土特色休闲农业方面具有得天独厚的自然资源、人文资源和社会条件,只要在合理规划利用、重点开发、政策引导下是大有作为的。     

基于C－SVM的大米品种识别研究

提出了一种基于支持向量机(C-SVM)区分大米品种的方法。首先对大米图像进行阈值分割、平滑处理等预处理,并根据大米的粒型特点,提取米粒的面积、周长等6个形态特征。利用Orange Canvas数据挖掘软件先对linear和RBF核函数进行核参数选择,并在Opencv 3.0环境下,编程实现K-means、linear和RBF的3种大米品种识别方法,对10组混合大米图像进行品种测试。试验结果表明,支持向量机线性核函数对大米品种识别具有较高的预测稳定性,识别分类准确率约为99%。     

皖南烟区适宜特色品种研究

在皖南烟区进行生产示范,通过研究各品种农艺性状、经济性状以及抗病性的差异,选择出适宜皖南烟区种植的特色品种。结果表明：KRK26、云烟97在农艺性状、经济性状及抗病性方面表现突出,其次是云烟87、粤烟97和K326。4个品种在皖南烟区烟农愿意接受程度为：云烟97〉KRK26〉粤烟97〉K326。     

基于特征空间的土壤含盐量的遥感反演

土壤表层含盐量的聚集是造成土壤盐渍化的主要原因,因此借助遥感手段及时、准确地对土壤含盐量进行研究有着重要的现实意义。以渭干河－库车河流域三角洲绿洲为研究区,采用2011年4月的Landsat卫星资料,利用改进型植被MSAVI和盐分指数（SI）构建土壤含盐量特征空间的遥感模型,并且通过2011年9月野外同步实测的地表0—10cm土壤含盐量进行相关性分析,R^2=0．8596,精度较好。这对干旱区绿洲农业的发展有着重要的现实意义。     

2010年7月22～24日三门峡市暴雨过程特征分析

采用NCEP/NCAR再分析资料和常规观测资料对2010年7月22～24日三门峡市暴雨过程进行诊断分析。结果表明,此次暴雨过程的暴雨区一直处于中低空低涡前部、切变线的南侧强风速带中,使得一直存在强烈的辐合上升运动;在暴雨区西部存在强烈的涡旋运动,低层辐合、高层辐散的形势为暴雨的发生提供了动力条件;从雷达基本速度产品分析出很多典型的中小尺度天气系统,这些系统直接导致了大强度降水;速度场上的逆风区（包括速度低值中心）能够很好地判别暴雨和暴雨落区,暴雨就发生在逆风区发生地或影响区周围。