Subgrade reaction modulus (Ks) is one of the main factors in evaluating engineering properties of soils for structural calculations and operations. So, many studies have been performed on the effect of other soil geot...Subgrade reaction modulus (Ks) is one of the main factors in evaluating engineering properties of soils for structural calculations and operations. So, many studies have been performed on the effect of other soil geotechnical parameters on it. One is the effect of soil grains shape on engineering properties of soils, especially Ks. The aim of the present research is to evaluate the effect of soil grains shape on Ks for coarse-grained soils of the west of Mashhad, Iran. For this purpose, 20 PLTs were performed on coarse-grained soils of the west of Mashhad and Ks amounts were determined. Then, flakiness and elongation of the samples measured and changes of Ks by soil grain shape were evaluated. The results showed the strength dependency of Ks to grain forms which an increase in flakiness and elongation indices leads to a decrease in Ks. Therefore, it is necessary to reduce Ks estimated form empirical relationships for flaky and elongated soils. So, by writing a genetic algorithm-based program to find the optimal relationship between the grain shape and the subgrade reaction coefficient, a valid equation for correcting the results from previous empirical equations was presented.展开更多
以饲料玉米为研究对象,采用化学计量学方法,利用全波段光谱数据建立玉米粗蛋白预测的简单快速精准预测模型。结果表明:原始光谱经去趋势算法预处理后,Rank-KS算法选择校正集和预测集,使用偏最小二乘(Partial least square,PLS)方法进行...以饲料玉米为研究对象,采用化学计量学方法,利用全波段光谱数据建立玉米粗蛋白预测的简单快速精准预测模型。结果表明:原始光谱经去趋势算法预处理后,Rank-KS算法选择校正集和预测集,使用偏最小二乘(Partial least square,PLS)方法进行建模,校正集和预测集的相关系数分别为0.9915和0.9813,校正集和预测集的均方根误差分别为0.0634和0.1138。预测集的相对分析误差RPD为5.02,大于评估阈值3.0。所建模型精度和稳定性较为理想,可满足在线生成检测的要求。展开更多
基金Supported by NSFC(Nos.12271108,12226413)Nature Science Foundation of Shandong Province(No.ZR2022MA001)Innovation Program of Shanghai Municipal Education Commission。
文摘Subgrade reaction modulus (Ks) is one of the main factors in evaluating engineering properties of soils for structural calculations and operations. So, many studies have been performed on the effect of other soil geotechnical parameters on it. One is the effect of soil grains shape on engineering properties of soils, especially Ks. The aim of the present research is to evaluate the effect of soil grains shape on Ks for coarse-grained soils of the west of Mashhad, Iran. For this purpose, 20 PLTs were performed on coarse-grained soils of the west of Mashhad and Ks amounts were determined. Then, flakiness and elongation of the samples measured and changes of Ks by soil grain shape were evaluated. The results showed the strength dependency of Ks to grain forms which an increase in flakiness and elongation indices leads to a decrease in Ks. Therefore, it is necessary to reduce Ks estimated form empirical relationships for flaky and elongated soils. So, by writing a genetic algorithm-based program to find the optimal relationship between the grain shape and the subgrade reaction coefficient, a valid equation for correcting the results from previous empirical equations was presented.
文摘以饲料玉米为研究对象,采用化学计量学方法,利用全波段光谱数据建立玉米粗蛋白预测的简单快速精准预测模型。结果表明:原始光谱经去趋势算法预处理后,Rank-KS算法选择校正集和预测集,使用偏最小二乘(Partial least square,PLS)方法进行建模,校正集和预测集的相关系数分别为0.9915和0.9813,校正集和预测集的均方根误差分别为0.0634和0.1138。预测集的相对分析误差RPD为5.02,大于评估阈值3.0。所建模型精度和稳定性较为理想,可满足在线生成检测的要求。
文摘目的禽流感疫情的爆发和传播受到多种自然因素的影响。今欲尝试将地理信息系统与基因进化树分析相结合，以建立一种基于基因序列变异追踪中国禽流感病毒地理传播的技术。方法禽流感病毒基因来源于美国国立医学图书馆（National Library for Medicine，NLM）数据库，所获得的基因组数据利用E—Utilities软件包转化为结构体后，可用Matlab软件阅读。结构体主要字段包括PB2、PBl、PA、HA、NP、HA、M1和NSl8个片段，分别代表流感病毒的8个不同的基因片段。基于结构体字段，利用计算生物学的方法比较不同传播能力禽流感病毒的同义突变／非同义突变基因（Ka／Ks）比例，确定不同选择压力之下A型禽流感病毒的基因突变模式。进而选择Ka／Ks比例最大的基因片段，采用Jukes—Cantor算法估计氨基酸序列变异的进化距离，然后对不同爆发点的H5N1型禽流感进行进化树聚类。将聚类信息输入Google Earth，并利用不同图层地理信息对影响爆发点分布的因素做单因素分析。结果比较分析A型禽流感所有的8个基因序列可以看出，NSl、HA和NA蛋白的Ka／Ks比值较大。三者中，HA基因的Ka／Ks比值最大，可以代表病毒的传播能力。利用分级聚类的思路对HA基因转录的氨基酸相似程度进行比较，发现自2003年以来亚洲地区爆发的H5N1型禽流感之间的关系可以表示为一个由30个节点构成的进化树，其中14个节点为分支节点，16个节点为叶子结点。把分支树的前三个节点作为分类标准，可以把所有16个病毒株分为四类。这四类病毒在地理空间的分布呈现一定规律。计算发现禽流感爆发相关地理因素排序分别为：内陆水体〉主要铁路交通线〉家禽密度。结论对中国HSNl病毒株基因序列变异的地理分布分析显示，禽流感病毒爆发与候鸟迁徙、家禽运输密切相关。
