期刊文献+
共找到5篇文章
< 1 >
每页显示 20 50 100
极端低温胁迫下秋茄LC-MS代谢组学分析 被引量:4
1
作者 郭晋敏 杨升 +4 位作者 陈秋夏 刘星 刘双双 王金旺 王文卿 《分子植物育种》 CAS 北大核心 2024年第23期7657-7668,共12页
为研究红树植物秋茄(Kandelia obovata)在极端低温胁迫下的代谢响应,以‘龙港’秋茄幼苗叶片为试验材料,-5℃处理为低温组,10℃处理为对照组,采用液相色谱与质谱联用技术(LC-MS)的代谢组学方法分析不同温度下‘龙港’秋茄幼苗叶片中代... 为研究红树植物秋茄(Kandelia obovata)在极端低温胁迫下的代谢响应,以‘龙港’秋茄幼苗叶片为试验材料,-5℃处理为低温组,10℃处理为对照组,采用液相色谱与质谱联用技术(LC-MS)的代谢组学方法分析不同温度下‘龙港’秋茄幼苗叶片中代谢物差异。结果显示:低温组与对照组共筛选出80种鉴定到物质名称且差异显著的代谢物。KEGG富集结果显示,其中9种差异代谢物显著富集到了α-亚麻酸代谢、亚油酸代谢、黄酮和黄酮醇的生物合成、苯丙氨酸代谢、植物激素信号转导这5条通路当中。在α-亚麻酸代谢、亚油酸代谢、黄酮和黄酮醇的生物合成和苯丙氨酸代谢通路当中,低温组中的9(S)-HOTrE、12-OPDA、9(S)-HpOTrE、9-OxoODE、9(S)-HODE、紫云英苷、槲皮素-3-O-葡萄糖苷和苯甲酰甲酸含量较对照组出现显著上调,其中9(S)-HOTrE、12-OPDA、9(S)-HpOTrE、9-OxoODE、9(S)-HODE属于不饱和脂肪酸类物质,紫云英苷和槲皮素-3-O-葡萄糖苷属于类黄酮类物质,苯甲酰甲酸属于苯及其替代衍生物。在苯丙氨酸代谢和植物激素信号传导通路当中,低温组中的水杨酸含量较对照组出现显著下调,水杨酸属于苯及其替代衍生物。本研究为明确‘龙港’秋茄响应极端低温胁迫的代谢表型和代谢策略奠定了基础,为秋茄抗寒良种的选育和分子改良提供依据。 展开更多
关键词 秋茄 低温胁迫 LC-MS 多元统计分析
原文传递
基于深度学习的苹果点云语义分割方法研究 被引量:1
2
作者 刘星 顾寄南 +2 位作者 黄则栋 张文浩 张伟 《中国农机化学报》 北大核心 2024年第8期223-227,245,共6页
点云数据可以准确、直观地反映苹果与树枝之间的空间关系,由于点云数据的不规则性,传统的卷积神经网络不适用于点云数据。因此,提出一种基于改进动态图卷积的苹果点云语义分割方法。基于动态图卷积DGCNN,采用不同尺度的K最近邻KNN构造... 点云数据可以准确、直观地反映苹果与树枝之间的空间关系,由于点云数据的不规则性,传统的卷积神经网络不适用于点云数据。因此,提出一种基于改进动态图卷积的苹果点云语义分割方法。基于动态图卷积DGCNN,采用不同尺度的K最近邻KNN构造各节点的邻域关系;在边缘卷积EdgeConv中加入邻居节点信息,提取更加丰富的局部特征;设计基于图的注意力模块,给中心点的K个最近邻居点分配不同的权重,相对于使用最大值池化对特征进行聚合操作,该注意力模块能更好地聚合邻接域特征信息;引入通道注意力模块,给不同特征分配不同的权重。试验表明,在苹果点云数据集上,该网络有较高的点云分割精度,整体精度OA和平均交并比MIOU分别达到91.2%和69.2%,相较于DGCNN,OA和MIOU分别提高3.9%、3.6%。 展开更多
关键词 苹果分类 DGCNN 语义分割 边缘卷积 混合注意力机制
在线阅读 下载PDF
舾装件附件自动匹配软件开发应用 被引量:1
3
作者 廖思溶 刘星 马玲 《广船科技》 2021年第3期40-42,2,共4页
基于建模精细化的要求,使用AM建模软件,为常用舾装件附件设计解决方案。主要为孔、垫板、紧固件、栏杆四个船舶设计常用舾装附件的自动匹配。
关键词 舾装件附件 自动匹配 建模
在线阅读 下载PDF
An Approach to Spectral Discrimination of Rocks Using ASAI and Rough Sets
4
作者 ZhangZhenfei HuGuangdao +5 位作者 YangMingguo liuxing WangZhenlmi LiWenhui ZhangXiaobing HeLi 《Journal of China University of Geosciences》 SCIE CSCD 2003年第3期257-260,共4页
Field data of outcrop spectrums provide important basis for modeling of hyper-spectral remote sensing aiming at mineral prospecting. We make an approach to the application of rough set theory in spectral discriminatio... Field data of outcrop spectrums provide important basis for modeling of hyper-spectral remote sensing aiming at mineral prospecting. We make an approach to the application of rough set theory in spectral discrimination of rocks. We build a decision table with an adequate number of samples (outcrops) of known rock type (the universe), of which the conditional attributes are discretized 'area spectrum absorption indexes' (ASAI) corresponding to wavelength intervals, and the decision attribute is rock type. We search to obtain the exhaustive set of reducts of the table, each of which will serve as a variable number of deduction rules. Suppose we have n (usually a very big number) rules in total and there are m types of rocks in our universe, for any unknown sample, we judge its rock type by each of those rules. An unknown sample may be recognized as a different type by different rules because it is outside our universe, and we accept the most frequent judgment result and ignore the other m-1 types of results. Our ASAI is an improvement upon the traditional spectrum absorption index (SAI), better applicable to field spectrums: given a spectrum curve and a wavelength interval, we take the average reflectance within the interval as a base line and let ASAI=a below/(a above+a below), where a below and a above stand for total areas, bounded by the curve, the base line and the borders of the intervalbelow and above the base line respectively. With the equipments of FieldSpectr Fr (made by ASD Co., US), we collected data from Baiya gold deposit, Yunnan, and applied the above method to discriminate altered rocks as an experiment. The results show satisfactory performance of the method. 展开更多
关键词 rough set spectral discrimination area spectrum absorption index
在线阅读 下载PDF
A Dilemma Arising from “Scientism” in Jurisprudence: How Does Legal Knowledge Become a Component of Legal Practice?
5
作者 liuxing 《Social Sciences in China》 2005年第2期175-176,共2页
Whether in “scientific” diachronic or synchronic jurisprudence, the proposition that “legal knowledge can and must be scientific knowledge” is doomed to failure. The failure comes from the insuperable dilemma pres... Whether in “scientific” diachronic or synchronic jurisprudence, the proposition that “legal knowledge can and must be scientific knowledge” is doomed to failure. The failure comes from the insuperable dilemma presented by the premiseacademic expectations.contained in its own When the methodsof observation, inference and analysis involved in legal evidence, inferences and conclusions, which may be highly effective in the positive natural or other positive social sciences, they seem to tread on thin ice, 展开更多
关键词 法律知识 法制建设 立法 法律文化 民主法制
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部