检索结果-南通市图书馆

Effect of fire intensity on active organic and total soil carbon in a Larix gmelinii forest in the Daxing'anling Mountains,Northeastern China

引用

Journal of Forestry Research 2016年第6期27卷 1351-1359页

作者： Yunmin Wei Haiqing Hu jiabao sun Qiang Yuan Long sun Huifeng Liu College of Forest Northeast Forestry University 26 He XingRoad Xiangfang District Harbin 150040 China Forest PROTECTION Research Institute in Heilongjiang Province 75Ha Ping Road Xiangfang DistrictHarbin 150040 China College of Life Sciences Northeast Agricultural University59 Wood Street Gongbin Road Xiangfang DistrictHarbin 150030 China College of Agriculture and Forest in Da Xing An Ling Area in Heilongjiang Province Jagedaqi 165000 China

Studying contents and seasonal dynamics of active organic carbon in the soil is an important method for revealing the turnover and regulation mechanism of soil carbon pool. Through 3 years of field sampling and lab analysis, we studied the seasonal variations, content differences, and interrelationships of total organic carbon （TOC）, light fraction organic carbon （LFOC）, and particulate organic carbon （POC） of the soil in the forest areas burned with different fire intensities in the Daxing＇anling Mountains. The mean TOC content in the low-intensity burned area was greater than that in the unburned area, moderate-intensity, and high-intensity burned areas in June and November （P 〈 0.05）. LFOC and POC in the low-intensity burned area were greater than that in either moderate-intensity or high-intensity burned areas, with significant differences in LFOC in September and November （P 〈 0.05）. A significant difference in LFOC between the unburned and burned areas was only found in July （P 〈 0.05）. However, the differences in POC between the unburned and burned areas were not significant in all the whole seasons （P 〉 0.05）. Soil LFOC and POC varied significantly with the seasons （P 〈 0.05） in the Daxing＇anling Mountains. Significant linear relationships were observed between soil TOC, LFOC, and POC, which were positively correlated with soil nitrogen and negatively correlated with soil temperature in the Daxing＇anling Mountains.

关键词： Forest fire intensity Labile organic carbon.Light fraction organic carbon Particulate organic matter carbon Total organic carbon

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Pig pangenome graph reveals functional features of non‑reference sequences

引用

Journal of Animal Science and Biotechnology 2024年第3期15卷 956-970页

作者： Jian Miao Xingyu Wei Caiyun Cao jiabao sun Yuejin Xu Zhe Zhang Qishan Wang Yuchun Pan Zhen Wang College of Animal Sciences Zhejiang UniversityHangzhou 310058ZhejiangChina Yazhou Bay Science and Technology City Hainan Institute of Zhejiang UniversityYazhou DistrictBuilding 11Yongyou Industrial ParkSanya 572025HainanChina

Background The reliance on a solitary linear reference genome has imposed a significant constraint on our compre-hensive understanding of genetic variation in *** constraint is particularly pronounced for non-reference sequences(NRSs),which have not been extensively *** In this study,we constructed a pig pangenome graph using 21 pig assemblies and identified 23,831 NRSs with a total length of 105 *** findings revealed that NRSs were more prevalent in breeds exhibiting greater genetic divergence from the reference ***,we observed that NRSs were rarely found within coding sequences,while NRS insertions were enriched in immune-related Gene Ontology ***,our investigation also unveiled a close association between novel genes and the immune capacity of *** observed substantial differences in terms of frequencies of NRSs between Eastern and Western pigs,and the heat-resistant pigs exhibited a substantial number of NRS insertions in an 11.6 Mb interval on chromosome ***,we discovered a 665 bp insertion in the fourth intron of the TNFRSF19 gene that may be associated with the ability of heat tolerance in South-ern Chinese *** Our findings demonstrate the potential of a graph genome approach to reveal important functional features of NRSs in pig populations.

关键词： Heat tolerance Immune ability Non-reference sequences Pig pangenome

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于随机子空间识别的模态参数不确定性量化方法

引用

振动与冲击 2024年第8期43卷 272-279页

作者：罗杰康杰孙嘉宝曾舒洪南京航空航天大学航天学院南京211106

基于协方差驱动随机子空间识别(covariance-driven stochastic subspace identification,SSI-COV)方法的模态参数识别具有强鲁棒性、高精度的优势,在结构工作模态分析中应用广泛。为保证模态参数识别的准确性,新近提出的基于随机子空间(... 详细信息

基于协方差驱动随机子空间识别(covariance-driven stochastic subspace identification,SSI-COV)方法的模态参数识别具有强鲁棒性、高精度的优势,在结构工作模态分析中应用广泛。为保证模态参数识别的准确性,新近提出的基于随机子空间(stochastic subspace identification,SSI)的模态参数不确定性量化方法,可有效估计模态参数的方差,但由于其计算各中间变量时,需显式表示出Jacobian矩阵,导致矩阵运算维度高、计算效率低。为此,提出一种基于SSI-COV的模态参数不确定度高效计算方法。首先,计算振动响应相关函数的方差,通过奇异值分解(singular value decomposition,SVD),选取合适的奇异值截断阶数,由每阶奇异向量组装出多组Hankel矩阵的扰动。其次,根据一阶矩阵摄动理论,隐式计算SSI-COV算法各中间变量的一阶扰动,最终,由多组模态参数的扰动叠加计算出方差。最后,以桁架结构模型为例,采用所提方法辨识结构模态参数并计算模态参数方差,分析了Hankel矩阵维度及相关函数奇异值截断阶数对辨识结果的影响,结果表明计算得到的模态参数方差与蒙特卡洛仿真(Monte Carlo simulation,MCS)结果非常接近,且模态参数不确定度可作为剔除虚假模态的有效依据。

关键词：模态分析随机子空间法不确定度量化非白激励

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

融合多工况功率谱密度函数的工作模态分析方法

引用

振动与冲击 2024年第4期43卷 179-189页

作者：曾舒洪康杰孙嘉宝罗杰南京航空航天大学航天学院南京211106

频域分解(frequency domain decomposition,FDD)方法是开展环境激励下结构工作模态分析(operational modal analysis,OMA)的常用方法。但是,现有的FDD方法存在一些不足:①无法剔除非白激励及谐波激励引起的虚假模态;②无法区分结构密集... 详细信息

频域分解(frequency domain decomposition,FDD)方法是开展环境激励下结构工作模态分析(operational modal analysis,OMA)的常用方法。但是,现有的FDD方法存在一些不足:①无法剔除非白激励及谐波激励引起的虚假模态;②无法区分结构密集模态与不相关非白激励产生的虚假模态。通过研究发现功率谱密度(power spectral density,PSD)矩阵的秩是FDD方法性能的决定性因素。在此基础上,提出一种新的工作模态识别OMA方法,该方法结合了不同激励工况下的响应PSD函数矩阵,并分别对单个激励工况下的响应PSD矩阵与多工况下的增广响应PSD矩阵进行奇异值分解,通过对比单工况PSD矩阵与增广PSD矩阵在奇异值峰值处秩的变化,识别出包括密集模态在内的结构模态参数,并消除由非白激励产生的虚假模态。采用桁架结构仿真算例和广州塔的工程数据集验证所提方法的有效性。

关键词：工作模态分析(OMA) 非白噪声激励密集模态功率谱密度(PSD)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

N-糖基硫代亚脲基-(硫代)磷酰胺二芳基和二烷基酯的合成

引用

有机化学 2003年第4期23卷 356-360页

作者：曹玲华周传健孙家宝刘育亭新疆大学化学系

二芳氧基磷酰肼 ( 2a ,2b)或二乙氧基硫代磷酰肼 ( 4 )与糖基异硫氰酸酯 ( 5a～ 5d)反应 ,生成相应的N 糖基硫代亚脲基 -磷酰胺二芳基酯 ( 6a～ 6d ,7a～ 7d)和N 糖基硫代亚脲基 -硫代磷酰胺二乙基酯 ( 8a～ 8d) .

关键词：糖基异硫氰酸酯硫代磷酰胺酯合成二芳氧基磷酰阱除草剂

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

自主工作模态分析方法研究综述

引用

机械工程学报 2023年第13期59卷 89-109页

作者：康杰王寅罗杰孙嘉宝曾舒洪南京航空航天大学航天学院南京211106

为适应结构健康监测对模态分析高效和自动化的需求,自主工作模态分析(Automated operational modal analysis,AOMA)在近二十年已成为结构动力学领域的研究热点之一。自动鉴别并剔除模态分析结果中的虚假模态,保留结构真实模态,是AOMA的... 详细信息

为适应结构健康监测对模态分析高效和自动化的需求,自主工作模态分析(Automated operational modal analysis,AOMA)在近二十年已成为结构动力学领域的研究热点之一。自动鉴别并剔除模态分析结果中的虚假模态,保留结构真实模态,是AOMA的核心和难点。现有AOMA方法可分为三类:(1)聚类法,核心是基于聚类算法自动挑选稳定图中的稳定模态作为真实模态,是目前的主流方法。(2)峰值提取法,自动挑选由真实模态引起的响应功率谱密度函数曲线或其奇异值曲线的峰值。(3)深度学习法,利用神经网络将工作模态分析问题转化为图像目标检测或时序分析问题。重点分析了三类方法的核心思想、分析流程及各自的特点,介绍了AOMA方法在工业软件及工程结构中的应用案例,最后阐明AOMA应用中应注意的问题及发展趋势。

关键词：工作模态分析自主辨识虚假模态聚类峰值提取深度学习

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Two-dimensional ferromagnetic superlattices

引用

National Science Review 2020年第4期7卷 745-754页

作者： Shanshan Liu Ke Yang Wenqing Liu Enze Zhang Zihan Li Xiaoqian Zhang Zhiming Liao Wen Zhang jiabao sun Yunkun Yang Han Gao Ce Huang Linfeng Ai Ping Kwan Johnny Wong ANDrew Thye Shen Wee Alpha T.N'Diaye Simon A.Morton Xufeng Kou Jin Zou Yongbing Xu Hua Wu Faxian Xiu State Key Laboratory of Surface Physics and Department of Physics Fudan University Institute for Nanoelectronic Devices and Quantum Computing Fudan University Laboratory for Computational Physical Sciences (MOE) Fudan University Department of Electronic Engineering Royal Holloway University of London School of Electronic Science and Engineering Nanjing University Materials Engineering The University of Queensland Department of Physics National University of Singapore Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore Lawrence Berkeley National Laboratory School of Information Science and Technology Shanghai Tech University Centre for Microscopy and Microanalysis The University of Queensland Collaborative Innovation Center of Advanced Microstructures

Mechanically exfoliated two-dimensional ferromagnetic materials(2 D FMs) possess long-range ferromagnetic order and topologically nontrivial skyrmions in few layers. However, because of the dimensionality effect, such few-layer systems usually exhibit much lower Curie temperature(TC) compared to their bulk counterparts. It is therefore of great interest to explore effective approaches to enhance their TC, particularly in wafer-scale for practical applications. Here, we report an interfacial proximity-induced high-TC2 D FM FeGe Te(FGT) via A-type antiferromagnetic material Cr Sb(CS) which strongly couples to FGT. A superlattice structure of(FGT/CS)n, where n stands for the period of FGT/CS heterostructure, has been successfully produced with sharp interfaces by molecular-beam epitaxy on 2-inch wafers. By performing elemental specific X-ray magnetic circular dichroism(XMCD) measurements, we have unequivocally discovered that TCof 4-layer FeGeTecan be significantly enhanced from 140 K to230 K because of the interfacial ferromagnetic coupling. Meanwhile, an inverse proximity effect occurs in the FGT/CS interface, driving the interfacial antiferromagnetic Cr Sb into a ferrimagnetic state as evidenced by double-switching behavior in hysteresis loops and the XMCD spectra. Density functional theory calculations show that the Fe-Te/Cr-Sb interface is strongly FM coupled and doping of the spin-polarized electrons by the interfacial Cr layer gives rise to the TCenhancement of the FeGeTefilms, in accordance with our XMCD measurements. Strikingly, by introducing rich Fe in a 4-layer FGT/CS superlattice, TCcan be further enhanced to near room temperature. Our results provide a feasible approach for enhancing the magnetic order of few-layer 2 D FMs in wafer-scale and render opportunities for realizing realistic ultra-thin spintronic devices.

关键词： 2D ferromagnetic material room temperature 2-inch Fe3GeTe2 film wafers proximity effect (Fe3GeTe2/CrSb)nsuperlattice

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

2023年世界田径锦标赛男子三级跳远起跳技术特征分析

引用

体育科技文献通报 2023年第8期31卷 11-12,16页

作者：孙家宝山东师范大学体育学院山东济南250358

本文通过对2023年世界田径锦标赛男子三级跳远起跳技术进行研究,运用文献资料、运动视频分析、数理统计等研究方法,对主要数据进行分析处理。研究结果表明:2023年世锦赛三级跳远前3名运动员起跳技术中,着地角均小于起跳角,支撑腿膝角缓... 详细信息

本文通过对2023年世界田径锦标赛男子三级跳远起跳技术进行研究,运用文献资料、运动视频分析、数理统计等研究方法,对主要数据进行分析处理。研究结果表明:2023年世锦赛三级跳远前3名运动员起跳技术中,着地角均小于起跳角,支撑腿膝角缓冲角度较小,运动员腿部力量较大;3名运动员的技术类型分别是:冠军跳跃型、亚军均衡型、季军跳跃型;在对三级跳运动动员进行训练时,应着重加强腿部力量的训练。

关键词：世界田径锦标赛三级跳远起跳技术技术分析

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

“变”与“不变”:高等教育数智化转型的趋向、风险与路径

引用

高校教育管理 2022年第6期16卷 23-31,58页

作者：张志华孙嘉宝季凯南京邮电大学教育科学与技术学院江苏南京210023

数智化时代,高等教育正面临以数字化、智能化、智慧化为特征的转型趋势,“变”与“不变”的辩证思维为把握高等教育数智化转型提供了新视野。相较于传统教育,数智技术赋能学生培养个性化、教师素养数字化和教育教学时空多元化的转变。... 详细信息

数智化时代,高等教育正面临以数字化、智能化、智慧化为特征的转型趋势,“变”与“不变”的辩证思维为把握高等教育数智化转型提供了新视野。相较于传统教育,数智技术赋能学生培养个性化、教师素养数字化和教育教学时空多元化的转变。在此过程中,高等教育“不变”的要素应是学生主体地位、教师主导角色、高校根本任务。“变”与“不变”中隐含学生无效认知负荷增加与被边缘化的风险,教师“数字鸿沟”扩大与“主奴悖论”蔓延的风险,教育教学的信息安全问题与人文关怀缺位的风险。基于此,学生应主动求变,提升数智技术个性化培养成效;教师应积极应变,提升自身数字素养与技能;高校应准确识变,促进数智化转型。

关键词：高等教育数智化技术赋能技术异化立德树人学生培养教师素养

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Tuning 2D magnetism in Fe3+XGeTe2 films by element doping

引用

National Science Review 2022年第6期9卷 163-170页

作者： Shanshan Liu Zihan Li Ke Yang Enze Zhang Awadhesh Narayan Xiaoqian Zhang Jiayi Zhu Wenqing Liu Zhiming Liao Masaki Kudo Takaaki Toriyama Yunkun Yang Qiang Li Linfeng Ai Ce Huang jiabao sun Xiaojiao Guo Wenzhong Bao Qingsong Deng Yanhui Chen Lifeng Yin Jian Shen Xiaodong Han Syo Matsumura Jin Zou Yongbing Xu Xiaodong Xu Hua Wu Faxian Xiu State Key Laboratory of Surface Physics and Department of Physics Fudan University Institute for Nanoelectronic Devices and Quantum Computing Fudan University College of Science University of Shanghai for Science and Technology Laboratory for Computational Physical Sciences(MOE) Fudan University Solid State and Structural Chemistry Unit Indian Institute of Science School of Electronic Science and Engineering Nanjing University Department of Physics University of Washington Department of Electronic Engineering Royal Holloway University of London Materials Engineering The University of Queensland Beijing Key Laboratory of Microstructure and Property of Advanced Materials Institute of Microstructure and Property of Advanced Materials Beijing University of Technology The Ultramicroscopy Research Center Kyushu University State Key Laboratory of ASIC and System School of Microelectronics Fudan University Collaborative Innovation Center of Advanced Microstructures Department of Applied Quantum Physics and Nuclear Engineering Kyushu University Centre for Microscopy and Microanalysis The University of Queensland Shanghai Research Center for Quantum Sciences

Two-dimensional(2D) ferromagnetic materials have been discovered with tunable magnetism and orbital-driven nodal-line features. Controlling the 2D magnetism in exfoliated nanoflakes via electric/magnetic fields enables a boosted Curie temperature(TC) or phase transitions. One of the challenges, however, is the realization of high TC2D magnets that are tunable, robust and suitable for large scale fabrication. Here, we report molecular-beam epitaxy growth of wafer-scale Fe3+XGeTe2films with TCabove room temperature. By controlling the Fe composition in Fe3+XGeTe2, a continuously modulated TCin a broad range of 185–320 K has been achieved. This widely tunable TCis attributed to the doped interlayer Fe that provides a 40% enhancement around the optimal composition X = 2. We further fabricated magnetic tunneling junction device arrays that exhibit clear tunneling signals. Our results show an effective and reliable approach, i.e. element doping, to producing robust and tunable ferromagnetism beyond room temperature in a large-scale 2D Fe3+XGeTe2fashion.

关键词： 2D ferromagnetic material Fe3+XGeTe2 film element doping above room temperature TC tunability

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：