检索结果-南通市图书馆

Geochronology and geochemistry of Cretaceous-Eocene granites,Tengchong Block(SW China):Petrogenesis and implications for Mesozoic-Cenozoic tectonic evolution of Eastern Tethys

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2022年第2期13卷 214-236页

作者： Yongqing Chen guangjie li Luxue Qin Yingxiang Lu Chengxing Jiang School of Earth Sciences and Resources China University of Geosciences(Beijing)Beijing 100083China Yunnan Geological Survey Kunming 650051China

The Early Cretaceous-Early Eocene granitoids in the Tengchong Block record the evolutionary history of the Mesozoic-Cenozoic tectono-magmatic evolution of Eastern Tethys.(a)The Early Cretaceous granitoids with relatively low(^(87)Sr/^(86)Sr)iratios of 0.7090-0.7169 andε_(Nd)(t)values of-9.8 to-7.8 display metaluminous,calc-alkaline dominated by I-type granite affinity and hybrid mantle-crust geochemical signatures.They may have been derived from melting of the subducted Meso-Tethyan BangongNujiang oceanic crust with terrigenous sediments in an arc-continent collisional setting.(b)The Late Cretaceous-Paleocene granitoids with relatively high(^(87)Sr/^(86)Sr)iratios of 0.7109-0.7627,andε_(Nd)(t)values of-12.1 to-7.9 exhibit metaluminous to peraluminous,calc-alkaline dominated by S-type granite affinity and hybrid Lower-Upper crust geochemical signatures,which may be originated from partial melting of the Meso-Proterozoic continental crust in the collision setting between the Tengchong Block and Baoshan Block.(c)The Early Eocene granitoids have metaluminous,calc-alkaline I-type and S-type granites dual affinity,with relatively high(^(87)Sr/^(86)Sr)iratios of 0.711-0.736,ε_(Nd)(t)values of-9.4 to-4.7,showing crust-mantle mixing geochemical signatures.They may have been originated from partial melting of the late Meso-Proterozoic upper crustal components mixed with some upper mantle material during the ascent process of mantle magma caused by the subduction of the Neo-Tethyan Putao-Myitkyian oceanic crust,and collision between the Western Burma Block and the Tengchong Block.It is these multi-stage subductions and collisions that caused the spatial and temporal distribution of the granitic rocks in the Tengchong Block.

关键词： Zircon U-Pb geochronology Sr-Nd-Pb isotopes Granites in the Tengchong Block Tectono-magmatic evolution Eastern Tethys tectonic domain SW China

Revealing the role of pyramidal slip in the high ductility of Mg-li alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第3期12卷 1021-1025页

作者： Jing Xu Bo Guan Yunchang Xin guangjie Huang Peidong Wu Qing liu International Joint Laboratory for light Alloys College of Materials Science and EngineeringChongqing UniversityChongqing 400030China Key Laboratory for light-weight Materials Nanjing Tech UniversityNanjing 210009China Department of Mechanical Engineering McMaster UniversityHamiltonON L8S 4L7Canada

The high ductility of Mg-li alloy has been mainly ascribed to a high activity of pyramidalslip to accommodate plastic strain.In the present study,however,a quantitative analysis reveals that li-addition can only slightly stimulate the activation of pyramidalslip under compression along the normal direction of a hot-rolled Mg-4.5 wt.%li plate,with a relative activity of approximately 18%.Although the limited activity of pyramidalslip alone cannot accommodate a large plastic strain,it effectively reduces the number of{10.11}−{10.12}double twins,which are believed to be favorable sites for crack initiation.The evidently reduced activity of double twins leads to a lower cracking tendency,and therefore improves ductility.

关键词： Mg alloy Plasticity Plastic deformation Slip Twinning.

Storage, form, and influencing factors of karst inorganic carbon in a carbonate area in China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第3期67卷 725-739页

作者： Chaochao DU Xiaoyong BAI Yangbing li Qiu TAN Cuiwei ZHAO guangjie LUO Luhua WU Fei CHEN Chaojun li Chen RAN Sirui ZHANG lian XIONG Fengjiao SONG Biqin XIAO Zilin li Yingying XUE Mingkang LONG Qing LUO Xiaoyun ZHANG Minghui li Xiaoqian SHEN Shu YANG State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China School of Geography and Environmental Sciences Guizhou Normal UniversityGuiyang 550001China CAS Center for Excellence in Quaternary Science and Global Change Xi'an 710061China Guizhou Provincial Key Laboratory of Geographic State Monitoring of Watershed Guizhou Normal CollegeGuiyang 550018China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China

Carbonate rock chemical weathering carbon sinks reduce the rate of increase of the atmospheric CO_(2) concentration and global warming. However, uncertainty still exists in the estimation results of carbonate rock chemical weathering carbon sink fluxes(CCSF), and the contributions of climate change and ecological restoration to the CCSF are not clear. To this end, we compiled published site data on ion concentrations in different watersheds in China and used a classical thermodynamic dissolution model to reassess the potential and spatial and temporal patterns of the CCSF in China from 1991 to 2020. We quantified the contributions of temperature(MAT), precipitation(MAP), evapotranspiration(ET), soil water(SM), and the normalized difference vegetation index(NDVI) to the CCSF. The results revealed that(1) China's CCSF was 22.76 t CO_(2)km^(-2)yr^(-1), which was higher than the global average(15.77 t CO_(2)km^(-2)yr^(-1)). The total carbonate rock chemical weathering carbon sink(CCS) was 4772.67×10^(4)t CO_(2), contributing 14.91% of the global CCS through a carbonate rock area of 252.98×10^(4)km^(-2).(2) China's CCSF decreased gradually from southeast to northwest, with values of 33.14, 12.93, and7.27 t CO_(2)km^(-2)yr^(-1)in the southern karst, Qinghai-Tibetan karst, and northern karst regions, respectively.(3) The overall CCSF in China exhibited an increasing trend from 1991 to 2020, with a rate of increase of 0.16 t CO_(2)km^(-2)yr^(-1).(4) The contributions of the MAP, MAT, ET, SM, and NDVI to the CCSF were 63.3%, 3.02%, 27.5%, 3.1%, and 3.05%, respectively. Among them, the increase in precipitation was the main contributor to the increase in the CCSF in China over the last 30 years, while the enhancement of ET offset part of the positive contribution of the increase in precipitation to the CCSF. In conclusion, the results of this study provide a systematic quantification of the magnitude, the patterns, and the influencing factors of CCS over a long time series in China. The results are of great significance an

关键词： Carbonate rocks Carbon sinks Patterns Influencing factors Thermodynamic dissolution modeling

Long‐life lithium batteries enabled by a pseudo‐oversaturated electrolyte

在线全文

学校读者我要写书评

暂无评论

Carbon Energy 2024年第4期6卷 115-127页

作者： Youchun Yu Simeng Wang Juyan Zhang Weiwei Qian Nana Zhang guangjie Shao Haiyan Bian Yuwen liu Lan Zhang Hebei Key Laboratory of Applied Chemistry College of Environmental and Chemical EngineeringYanshan UniversityQinhuangdaoChina Beijing Key Laboratory of Ionic liquids Clean Process CAS Key Laboratory of Green Process and EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijingChina Haike Group Research Institute of Innovation&Technology DongyingChina Langfang Green Industrial Technology Center LangfangChina

The specific energy of li metal batteries(LMBs)can be improved by using high‐voltage cathode materials;however,achieving long‐term stable cycling performance in the corresponding system is particularly challenging for the liquid electrolyte.Herein,a novel pseudo‐oversaturated electrolyte(POSE)is prepared by introducing 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl ether(TTE)to adjust the coordination structure between diglyme(G2)and lithium bis(trifluoromethanesulfonyl)imide(liTFSI).Surprisingly,although TTE shows little solubility to liTFSI,the molar ratio between liTFSI and G2 in the POSE can be increased to 1:1,which is much higher than that of the saturation state,1:2.8.Simulation and experimental results prove that TTE promotes closer contact of the G2 molecular with li^(+)in the POSE.Moreover,it also participates in the formation of electrolyte/electrode interphases.The electrolyte shows outstanding compatibility with both the li metal anode and typical high‐voltage cathodes.li||li symmetric cells show a long life of more than 2000 h at 1 mA cm^(−2),1 mAh cm^(−2).In the meantime,li||liNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cell with the POSE shows a high reversible capacity of 134.8 mAh g^(−1 )after 900 cycles at 4.5 V,1 C rate.The concept of POSE can provide new insight into the li^(+)solvation structure and in the design of advanced electrolytes for LMBs.

关键词： high voltage lithium metal batteries pseudo‐oversaturated electrolyte solid electrolyte interphases(SEI) solvation structure

STABIliTY ANALYSIS OF THE SPliT-STEP THETA METHOD FOR NONliNEAR REGIME-SWITCHING JUMP SYSTEMS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2021年第2期39卷 192-206页

作者： guangjie li Qigui Yang School of Mathematics and Statistics Guangdong University of Foreign StudiesGuangzhou 510420China Department of Mathematics South China University of TechnologyGuangzhou 510640China

In this paper,we investigate the stability of the split-step theta(SST)method for a class of nonlinear regime-switching jump systems–neutral stochastic delay differential equations(NSDDEs)with Markov switching and jumps.As we know,there are few results on the stability of numerical solutions for NSDDEs with Markov switching and jumps.The purpose of this paper is to enrich conclusions in such respect.It first devotes to show that the trivial solution of the NSDDE with Markov switching and jumps is exponentially mean square stable and asymptotically mean square stable under some suitable conditions.If the drift coefficient also satisfies the linear growth condition,it then proves that the SST method applied to the NSDDE with Markov switching and jumps shares the same conclusions with the exact solution.Moreover,a numerical example is demonstrated to illustrate the obtained results.

关键词： Exponential mean-square stability Neutral stochastic delay differential equa-tions Split-step theta method Markov switching and jumps.

机器换人的储蓄效应——技术变革中的收入冲击、消费变动与风险偏好演化

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

劳动经济研究 2024年第1期12卷 28-56页

作者：李超宁光杰山东大学商学院山东大学生活质量与公共政策研究中心

机器换人与居民高储蓄率是近些年中国经济的重要现象,而关于二者的内在关联及影响机理尚待系统研究。本文基于技术变革视角,对中国持续居高的居民储蓄提出了新解释。研究表明:人工智能带来的机器换人显著增强了储蓄偏好,其他因素不变时... 详细信息

机器换人与居民高储蓄率是近些年中国经济的重要现象,而关于二者的内在关联及影响机理尚待系统研究。本文基于技术变革视角,对中国持续居高的居民储蓄提出了新解释。研究表明:人工智能带来的机器换人显著增强了储蓄偏好,其他因素不变时,微观主体受机器换人的影响每提高一个标准差,储蓄平均增加21.45%。该结论在利用不同机器换人和储蓄指标、区域双重差分、工具变量、惩罚回归等方法进行稳健性与内生性检验时均成立。影响机制在于,机器换人虽降低了收入,但会通过减少双倍消费增加储蓄。深层次原因是,机器换人降低了居民的风险偏好,促使其减少享受型与发展型消费。研究还发现,人工智能是任务偏向型而非技能偏向型技术进步,提升劳动者教育水平不足以弱化其影响,但促进劳动者自由流动、加强劳动保护有助于降低其不利冲击。因此应充分重视人工智能的潜在冲击,积极出台与新技术相适应的配套措施,着力激发消费潜能、释放内循环的经济活力。

关键词：机器换人储蓄偏好收入冲击风险偏好

LSTM-based argument recommendation for non-API methods

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2020年第9期63卷 5-26页

作者： guangjie li Hui liU Ge li Sijie SHEN Hanlin TANG School of Computer Science and Technology Beijing Institute of Technology School of Electronics Engineering and Computer Science Peking University

Automatic code completion is one of the most useful features provided by advanced IDEs. Argument recommendation, as a special kind of code completion, is widely used as well. While existing approaches focus on argument recommendation for popular APIs, a large number of non-API invocations are requesting for accurate argument recommendation as well. To this end, we propose an LSTM-based approach to recommending non-API arguments instantly when method calls are typed in. With data collected from a large corpus of open-source applications, we train an LSTM neural network to recommend actual arguments based on identifiers of the invoked method, the corresponding formal parameter, and a list of syntactically correct candidate arguments. To feed these identifiers into the LSTM neural network, we convert them into fixed-length vectors by Paragraph Vector, an unsupervised neural network based learning algorithm. With the resulting LSTM neural network trained on sample applications, for a given call site we can predict which of the candidate arguments is more likely to be the correct one. We evaluate the proposed approach with tenfold validation on 85 open-source C applications. Results suggest that the proposed approach outperforms the state-of-the-art approaches in recommending non-API arguments. It improves the precision significantly from 71.46% to 83.37%.

关键词： argument recommendation LSTM deep learning non-API

Dynamics of a stochastic Holling II predator-prey model with Levy jumps and habitat complexity

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2021年第6期14卷 297-312页

作者： guangjie li Qigui Yang School of Mathematics and Statistics Guangdong University of Foreign Studies Guangzhou 510006P.R.China Department of Mathematics South China University of Technology Guangzhou 510640P.R.China

This paper investigates a stochastic Holling II predator-prey model with Levy jumps and habit complexity.It is first proved that the established model admits a unique global positive solution by employing the Lyapunov technique,and the stochastic ultimate boundedness of this positive solution is also obtained.Sufficient conditions are established for the extinction and persistence of this solution.Moreover,some numerical simulations are carried out to support the obtained results.

关键词： Stochastic predator-prey model jumps Holling II type functional response habitat complexity stochastic ultimate boundedness persistence and extinction.

高效跨域的Transformer小样本语义分割网络

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

计算机工程与应用 2024年第4期60卷 142-152页

作者：方红李德生蒋广杰上海第二工业大学数理与统计学院上海201209 上海第二工业大学资源与环境工程学院上海201209

小样本语义分割旨在仅使用数个标注样本学习目标类别特征并完成分割任务。主流研究存在的主要问题是:训练效率低下,训练和测试在同一数据域。为此构建了一种基于Transformer的高效、跨域的小样本语义分割网络SGFNet。在编码层,使用共享... 详细信息

小样本语义分割旨在仅使用数个标注样本学习目标类别特征并完成分割任务。主流研究存在的主要问题是:训练效率低下,训练和测试在同一数据域。为此构建了一种基于Transformer的高效、跨域的小样本语义分割网络SGFNet。在编码层,使用共享权重的MixVisionTransformer构建孪生网络,用于提取支持集和查询集的图像特征;在关系计算层,通过计算支持集图像特征向量与其对应mask的哈达玛积,提取目标类别的高维特征,并与查询集图像特征进行关系计算;在解码层,改进基于MLP的解码器,提出了残差解码器,将不同层级的特征解码得到最终分割结果。实验表明,该模型只需要在FSS-1000数据集上使用单张3090 GPU训练1.5~4.0 h,即可在FSS-1000数据集上获得最优结果1-shot mIoU 87.0%,在PASCAL-5i和COCO-20i数据集进行跨域测试达到非跨域的效果,1-shot mIoU分别为60.4%和33.0%,证明了该模型高效且跨域。

关键词：小样本语义分割(FSS) 跨域 Transformer 小样本学习(FSL) 语义分割