检索结果-南通市图书馆

Highly Hydrolysis-Resistant Polyimide Fibers Prepared by Thermal Crosslinking with Inherent Carboxyl Groups

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第2期42卷 247-255,I0010页

作者： Can-Can Zhang Jun-long Yang Ya-Jiang Huang Guang-Xian Li College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering of ChinaSichuan UniversityChengdu610065China

Easy hydrolysis in alkaline environments limits the use of polyimide fibers in environmental protection. The hydrolysis resistance levels of polyimide fibers can be improved by crosslinking of the macromolecular chains. In this work, crosslinked polyimide fibers(CPI fibers) were produced by intrinsic carboxyl decarboxylation for the first time. The thermal stability of the polyimide fibers containing the intrinsic carboxyl groups(PIC fibers) was studied, and the temperature of the decarboxylation-crosslinking reaction was determined to be 450 ℃. The PIC fibers were hotdrawn to initiate thermal crosslinking of the carboxyl groups and molecular chain orientation at high temperature. The CPI fibers had high tensile strengths(0.72-1.46 GPa) and compressive strengths(401-604 MPa). The oriented macromolecules and chemically crosslinked structure improved the tightness of the molecular chains and endowed the CPI fibers with excellent hydrolytic resistance. The CPI-50 fiber did not dissolve in a 0.5 wt% NaOH solution during heating at 90 ℃ for 10 h, and the tensile strength retention reached 87% when treated in 0.5 wt% NaOH solutions at 90 ℃ for 1 h, providing a guarantee for its application in alkaline corrosive environments.

关键词： Polyimide Carboxyl group Crosslinking Hydrolysis-resistance

Differences and identification on multi-time hydrocarbon generation of carboniferous-permian coaly source rocks in the Huanghua Depression,Bohai Bay Basin

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 765-776页

作者： Jin-Jun xu Xian-Gang Cheng Shu-Nan Peng Jun-Cai Jiang Qi-long Wu Da Lou Fu-Qi Cheng La-Mei Lin National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao 266580ShandongChina PetroChina Dagang Oilfield Company Tianjin300280China

Coal is a solid combustible mineral,and coal-bearing strata have important hydrocarbon generation potential and contribute to more than 12%of the global hydrocarbon resources.However,the deposition and hydrocarbon evolution process of ancient coal-bearing strata is characterized by multiple geological times,leading to obvious distinctions in their hydrocarbon generation potential,geological processes,and production,which affect the evaluation and exploration of hydrocarbon resources derived from coaly source rocks worldwide.This study aimed to identify the differences on oil-generated parent macerals and the production of oil generated from different coaly source rocks and through different oil generation processes.Integrating with the analysis of previous tectonic burial history and hydrocarbon generation history,high-temperature and high-pressure thermal simulation experiments,organic geochemistry,and organic petrology were performed on the Carboniferous-Permian(C-P)coaly source rocks in the Huanghua Depression,Bohai Bay Basin.The oil-generated parent macerals of coal's secondary oil generation process(SOGP)were mainly hydrogen-rich collotelinite,collodetrinite,sporinite,and cutinite,while the oil-generated parent macerals of tertiary oil generation process(TOGP)were the remaining small amount of hydrogen-rich collotelinite,sporinite,and cutinite,as well as dispersed soluble organic matter and unexhausted residual hydrocarbons.Compared with coal,the oil-generated parent macerals of coaly shale SOGP were mostly sporinite and cutinite.And part of hydrogen-poor vitrinite,lacking hydrocarbon-rich macerals,and macerals of the TOGP,in addition to some remaining cutinite and a small amount of crude oil and bitumen from SOGP contributed to the oil yield.The results indicated that the changes in oil yield had a good junction between SOGP and TOGP,both coal and coaly shale had higher SOGP aborted oil yield than TOGP starting yield,and coaly shale TOGP peak oil yield was lower than SOGP peak oil yield.There were significa

关键词： Thermal simulation Multi-time oil generation processes Coaly source rock Carboniferous-permian Huanghua Depression

Unraveling magnetic properties and martensitic transformation in Mn-rich Ni-Mn-Sn alloys:first-principles calculations and experiments

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第4期43卷 1769-1785页

作者： Yu Zhang Jing Bai Ke-Liang Guo Jia-Xin xu Jiang-long Gu Nicola Morley Qui-Zhi Gao Yu-Dong Zhang Claude Esling Xiang Zhao Liang Zuo Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education) School of Material Science and EngineeringNortheastern University Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province School of Resources and Materials Northeastern University at Qinhuangdao Department of Material Science and Engineering University of Sheffield State Key Laboratory of Metastable Materials Science and Technology Yanshan University Laboratoire d'Etude des Microstructures Et de Mecanique des Materiaux University of Lorraine

We have investigated the phase stability,magnetic properties,and martensitic transformation thermodynamics/kinetics of the Ni24-xMn18+x+ySn6-y(x,y=0,1,2) system by combining the first-principles calculations and experiments.The calculation results show that the optimized lattice parameters are consistent with the experimental data.Respectively,we obtain the relation equation for the austenite formation energy(Eform-A) and Mn content(XMn):Eform-A=507.358XMn-274.126,as well as for the six-layer modulated(6M) martensite formation energy(Eform-6M) and Ni content(XNi):Eform-6M=-728.484XNi+264.374.The ternary phase diagram of the total magnetic moment was established.The excess Mn will reduce the total magnetic moment of 6M(Mag6M) and non-modulated(NM)(MagNM) martensites,with the following equations relating the total magnetic moment and Mn content:Mag6M=-15.905XMn+7.902and MagNM=-14.781XMn+7.411,while the effect on austenite is complex.The variation of total magnetic moment is mainly dominated by the Mn atomic magnetic moment.The 3d electrons of MnSn(Mn at Sn sublattice)play an important role in magnetic properties from the perspective of the electronic density of states.Based on the thermodynamics of martensitic transformation,the alloys will likely undergo austenite?6M?NM transformation sequence.Combining the thermodynamic and kinetic results,the martensitic transformation temperature decreases with x increasing and increases with y increasing.These results are expected to provide reference for predicting the phase stability and magnetic properties of NiMn-Sn alloys.

关键词： Ni–Mn–Sn First-principles calculations Martensitic transformation Magnetic property Kinetics

Achieving laparoscopic anatomic resection for hepatocellular carcinoma by fluorescence guided positive staining of hepatic cone unit

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2024年第4期23卷 406-411页

作者： Jun-Fang Deng Chuan-Hui Peng Yu Zhang Xiao-Feng xu Rong-Liang Tong Zheng-long Zhai Di-Yu Chen Cheng Zhang Li-Ming Wu Jian Wu Division of Hepatobiliary Pancreatic Surgery the First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China

Laparoscopic anatomical liver resection has been increasingly reported worldwide,but how to demarcate the resection planes is technically challenging[1].Positive staining technique with intraoperative indocyanine green(ICG)-fluorescence imaging has been introduced as an effective tool for real-time intraoperative guidance[2].Liver anatomy is complex.Generally,liver is composed of 9 segments,each is composed of two to three subsegments,and each subsegment contains several hepatic cone units.A hepatic cone unit is dominated by a tertiary or quaternary hepatic pedicles[3].

关键词： hepatic resection anatomy

Spatiotemporal variations in glacier area and surface velocity of the northern Antarctic Peninsula during 2018-2022

在线全文

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2024年第2期15卷 297-311页

作者： Yu-long KANG Shi-Chang KANG Wan-Qin GUO Tao CHE Zong-Li JIANG Zhen-Feng WANG Qiang-Qiang xu Cheng-De YANG State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100083China Key Laboratory of Remote Sensing of Gansu Province Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China School of Earth Sciences and Spatial Information Engineering Hunan University of Science and TechnologyXiangtan 411201China

Ice sheet serves as a crucial indicator for assessing climate change.Mass loss in recent remote sensing-based studies indicated that the Antarctic Peninsula has rapid rates of glacier retreat and speed up of surface velocity.However,observations of seasonal variability of ice speed are limited,and glacier-area changes require multi-temporal monitoring.This study investigated the changes in area and surface velocities of∼375 glaciers on the northern Antarctic Peninsula(NAP)utilizing satellite images acquired by the Sentinel 1&2 satellites during 2018-2022.The results indicate that the glacier area reduced by approximately 166.1±44.2 km^(2)(-0.2%±0.1%per year)during the study period,with an acceleration after 2020(-0.4%±0.3%per year),and the most dramatic reduction happened on the eastern NAP.The maximum annual ice speeds on the NAP generally exceeded 3500 m per year,while the ice speeds in 2021 were the highest(exceeded 4210 m per year).The ice speed variability in austral autumn was higher than in other seasons,meanwhile the summer ice speeds showed an increasing trend.The glacier G012158E47018N,McNeile Glacier,glacier G299637E64094S and Drygalski Glacier showed the most remarkable ice speed variations represented by high daily velocities and strong fluctuations on their termini.Our results demonstrated that the variations in glacier area and seasonal ice speed on the NAP were responsive to the ice-ocean-atmosphere processes.Therefore,seasonal velocity and area variations should be considered when conducting accurate mass balance calculations,model validations and change mechanism analyses under climate warming scenarios.

关键词： Glacier area Seasonal ice speed Sentinel 1&2 Northern Antarctic Peninsula Ice-ocean-atmosphere processes

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

有自由面的裂隙网络稳定渗流试验与数值分析

岩土力学 2024年第3期45卷 878-884页

作者：张旭盛建龙叶祖洋周新武汉科技大学资源与环境工程学院湖北武汉430081 冶金矿产资源高效利用与造块湖北省重点实验室湖北武汉430081

为探究裂隙网络含自由面的稳定渗流特性,设计可视化的二维裂隙网络渗流试验装置,通过调节裂隙网络模型的上、下游水头开展一系列裂隙网络渗流试验,依次记录自由面水头高度和渗流流量大小;同时基于有限元软件COMSOL Multiphysics中的Darc... 详细信息

为探究裂隙网络含自由面的稳定渗流特性,设计可视化的二维裂隙网络渗流试验装置,通过调节裂隙网络模型的上、下游水头开展一系列裂隙网络渗流试验,依次记录自由面水头高度和渗流流量大小;同时基于有限元软件COMSOL Multiphysics中的Darcy接口,建立等比例二维裂隙网络数值模型,复现试验工况并与试验结果对比分析。对比发现试验结果与模拟结果基本吻合,这验证了试验结果的有效性以及数值模拟的准确性。研究结果表明:影响自由面变化的主要因素为上、下游水头高度及二者高度差:渗流水力梯度越大,自由面位置的下降越快;渗流水力梯度相同的水力条件,上、下游水头越高,形成的自由面水头越高,自由面降落曲线也越陡。其中,若上、下游水头高度不处于近似的水平,二者对于自由面位置的影响存在较大差异。自由面变化的基本规律符合Dupuit公式的表述。稳定渗流的水力梯度与平均流量仅在流量较小时符合线性相关,随着水力梯度的增加,二者关系呈现明显的非线性。

关键词：稳定渗流裂隙网络自由面透水层渗流水力梯度水头

PSRDP:A Parallel Processing Method for Pulsar Baseband Data

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第1期24卷 300-310页

作者： Ya-Zhou Zhang Hai-long Zhang Jie Wang Xin-Chen Ye Shuang-Qiang Wang xu Du Han Wu Ting Zhang Shao-Cong Guo Meng Zhang Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210008China National Astronomical Data Center Beijing 100101China Southeast University Nanjing 211189China School of Cyber Science and Engineering Qufu Normal UniversityQufu 273165China

To address the problem of real-time processing of ultra-wide bandwidth pulsar baseband data,we designed and implemented a pulsar baseband data processing algorithm(PSRDP)based on GPU parallel computing technology.PSRDP can perform operations such as baseband data unpacking,channel separation,coherent dedispersion,Stokes detection,phase and folding period prediction,and folding integration in GPU clusters.We tested the algorithm using the J0437-4715 pulsar baseband data generated by the CASPSR and Medusa backends of the Parkes,and the J0332+5434 pulsar baseband data generated by the self-developed backend of the Nan Shan Radio Telescope.We obtained the pulse profiles of each baseband data.Through experimental analysis,we have found that the pulse profiles generated by the PSRDP algorithm in this paper are essentially consistent with the processing results of Digital Signal Processing Software for Pulsar Astronomy(DSPSR),which verified the effectiveness of the PSRDP algorithm.Furthermore,using the same baseband data,we compared the processing speed of PSRDP with DSPSR,and the results showed that PSRDP was not slower than DSPSR in terms of speed.The theoretical and technical experience gained from the PSRDP algorithm research in this article lays a technical foundation for the real-time processing of QTT(Qi Tai radio Telescope)ultra-wide bandwidth pulsar baseband data.

关键词： (stars:)pulsars:general methods:data analysis techniques:miscellaneous

A Cross-matching Service for Data Center of Xinjiang Astronomical Observatory

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第1期24卷 119-127页

作者： Hai-long Zhang Jie Wang Xin-Chen Ye Wan-Qiong Wang Jia Li Ya-Zhou Zhang xu Du Han Wu Ting Zhang Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210008China National Astronomical Data Center Beijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Cross-matching is a key technique to achieve fusion of multi-band astronomical catalogs. Due to different equipment such as various astronomical telescopes, the existence of measurement errors, and proper motions of the celestial bodies, the same celestial object will have different positions in different catalogs, making it difficult to integrate multi-band or full-band astronomical data. In this study, we propose an online cross-matching method based on pseudo-spherical indexing techniques and develop a service combining with high performance computing system(Taurus) to improve cross-matching efficiency, which is designed for the Data Center of Xinjiang Astronomical Observatory. Specifically, we use Quad Tree Cube to divide the spherical blocks of the celestial object and map the 2D space composed of R.A. and decl. to 1D space and achieve correspondence between real celestial objects and spherical patches. Finally, we verify the performance of the service using Gaia 3 and PPMXL catalogs. Meanwhile, we send the matching results to VO tools-Topcat and Aladin respectively to get visual results. The experimental results show that the service effectively solves the speed bottleneck problem of crossmatching caused by frequent I/O, and significantly improves the retrieval and matching speed of massive astronomical data.

关键词： virtual observatory tools astronomical databases:miscellaneous catalogs

Monothetic and conductive network and mechanical stress releasing layer on micron-silicon anode enabling high-energy solid-state battery

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第3期43卷 1017-1029页

作者： Xiang Han Min xu Lan-Hui Gu Chao-Fei Lan Min-Feng Chen Jun-Jie Lu Bi-Fu sheng Peng Wang Song-Yan Chen Ji-Zhang Chen College of Materials Science and Engineering Co-Innovation Center of Efficient Processing and Utilization of Forestry ResourcesNanjing Forestry UniversityNanjing210037China Department of Physics Xiamen UniversityXiamen361005China Western Digital Corporation MilpitasCA95035USA

Silicon has ultrahigh capacity,dendrite-free alloy lithiation mechanism and low cost and has been regarded as a promising anode candidate for solid-state battery.Owing to the low infiltration of solid-state electrolyte(SSE),not the unstable solid-electrolyte interphase(SEI),but the huge stress during lithiation-and delithiation-induced particle fracture and conductivity lost tend to be the main issues.In this study,starting with micron-Si,a novel monothetic carbon conductive framework and a MgO coating layer are designed,which serve as electron pathway across the whole electrode and stress releasing layer,respectively.In addition,the in situ reaction between Si and SSE helps to form a LiF-rich and mechanically stable SEI layer.As a result,the mechanical stability and charge transfer kinetics of the uniquely designed Si anode are significantly improved.Consequently,high initial Coulombic efficiency,high capacity and durable cycling stability can be achieved by applying the Si@MgO@C anode in SSB.For example,high specific capacity of 3224.6 mAh·g^(-1)and long cycling durability of 200 cycles are achieved.This work provides a new concept for designing alloy-type anode that combines surface coating on particle and electrode structure design.

关键词： Lithium-ion battery(LIB) Solid-state electrolyte(SSE) Silicon anode Stress relief Coating