排序方式: 共有117条查询结果,搜索用时 15 毫秒
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本文收集处理了2014年9月到2015年9月一年的国家精细化指导预报资料(以下简称SCMOC);利用德州11个县市区的实况资料对其20点起报的日最低气温、日最高气温、晴雨、一般性降水,逐日3h预报气温进行对比分析,检验预报质量。通过研究发现:日最低气温质量较好,不需订正,日最高气温预报质量较差,无直接参考价值需订正,二者都具有明显季节变化特征;通过误差分析探索了误差特点,算出平均绝对误差;逐3h气温预报有明显的日变化以及季节变化特征;一般性降水预报质量不稳定,其中的48h预报质量高于24小时预报质量,降水预报空报率较高。通过研究总结要素误差特点为今后提高预报准确率提供参考。 相似文献
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提出了一种基于纳米金粒子比色法的汞离子检测方法,采用铋试剂-Ⅱ修饰的纳米金粒子胶体悬浮液检测汞离子。汞离子与铋试剂-Ⅱ选择性配位,使纳米金粒子胶体悬浮液反团聚,汞离子浓度与溶液吸光度呈一定的线性关系,线性范围为0.05μg/L~1mg/L,相对标准偏差为1.98%~3.52%。在实验条件下,采用Savitzky-Golay一阶导数对连续投影算法提取的特征波长进行了预处理,通过线性支持向量机回归模型进行建模与分析,该模型具有良好的自预测能力和实际预测能力。校正集的相关系数为0.9685,均方根误差为0.0412mg/L,验证集的相关系数为0.9600,均方根误差为0.0434mg/L。本文方法为提高汞离子浓度的检测效率提供了有效支持。 相似文献
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鸡组织滴虫是小鸡与青年鸡的一种原生虫类传染病,以损害肝脏与盲肠为主要特征。由于此病能引起肝脏、肓肠发生炎性病变,故又叫做盲肠肝炎。 相似文献
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Quick and accurate assessment of fish freshness is of great significance for intelligent quality monitoring and ensuring the safety of consumers. In the current fish freshness evaluation method based on visual images, the study of fish gills needs to remove the gill cover, which is invasive to the fish body, and the analysis of other parts has a low evaluation accuracy. To solve the above problems, a fish freshness classification method based on color histogram & grey-level co-occurrence matrix-linear discriminant analysis (CHG-LDA) was proposed. Firstly, preprocessing operations such as labeling, image zooming and color space conversion were performed on the collected fish images. Secondly, the extracted color histogram features and grey-level co-occurrence matrix (GLCM) features were fused to constitute the features, and the feature dimension was reduced by LDA. Finally, K-nearest neighbor (KNN) algorithm was used to classify fish freshness. The CHG-LDA method proposed solved the problem of poor classification performance caused by the low quality of the extracted fish image features. The experiment was carried out on a real crucian data set, and the index values of precision, recall, F1-score and accuracy were all 1. Compared with color histogram features, color moment, GLCM features, etc., this method improved the performance of each evaluation index on KNN, RF, ANN, and LightGBM classifiers. Among them, the evaluation time of KNN was the best, which was 0.01s. Experimental results showed that this method can achieve accurate and non-destructive evaluation of fish freshness, and it was feasible for actual production monitoring. 相似文献
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布鲁氏菌病是由布鲁氏菌属细菌引起的人兽共患的常见传染病.为了预防、控制和净化布病按照《布鲁氏菌病防治技术规范》的要求非疫区以监测为主;稳定控制区以监测净化为主;控制区和疫区实行监测、扑杀和免疫相结合的综合防治措施.本试验主要通过对免疫前和免疫后的牛羊用布病虎红平板凝集试验进行定期跟踪监测,以此说明对单头(只)牛羊用注射器进行喂服比将疫苗放到饮水中动物自由饮用免疫效果好. 相似文献
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