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Multi-dimensional multiplexing optical secret sharing framework with cascaded liquid crystal holograms 被引量:3
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作者 Keyao Li Yiming Wang +6 位作者 Dapu Pi Baoli Li Haitao Luan Xinyuan Fang Peng Chen Yanqing Lu Min Gu 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2024年第1期28-35,共8页
Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since... Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since the amount of available information channels is limited.Herein,we propose and demonstrate an optical secret sharing framework based on the multi-dimensional multiplexing liquid crystal(LC)holograms.The LC holograms are used as spatially separated shares to carry secret images.The polarization of the incident light and the distance between different shares are served as secret keys,which can significantly improve the information security and capacity.Besides,the decryption condition is also restricted by the applied external voltage due to the variant diffraction efficiency,which further increases the information security.In implementation,an artificial neural network(ANN)model is developed to carefully design the phase distribution of each LC hologram.With the advantage of high security,high capacity and simple configuration,our optical secret sharing framework has great potentials in optical encryption and dynamic holographic display. 展开更多
关键词 holographic encryption optical secret sharing cascaded liquid crystal hologram multi-dimensional multiplexing
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Heavy oil component characterization with multi-dimensional unilateral NMR 被引量:4
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作者 Liu Huabing Xiao Lizhi +6 位作者 Guo Baoxin Zhang Zongfu Zong Fangrong Deng Feng Yu Huijun V.Anferov S.Anferova 《Petroleum Science》 SCIE CAS CSCD 2013年第3期402-407,共6页
Heavy oil is a complicated mixture and a potential resource and has attracted much attention since the end of last century. It is important to characterize the composition of heavy oil to enhance its recovery efficien... Heavy oil is a complicated mixture and a potential resource and has attracted much attention since the end of last century. It is important to characterize the composition of heavy oil to enhance its recovery efficiency. A designed unilateral Nuclear Magnetic Resonance (NMR) sensor with a Larmor frequency of 20 MHz and a well-defined constant gradient of 23.25 T/m was employed to acquire three- dimensional (3D) data for three heavy oil samples. The highly-constant gradient is advantageous for diffusion coefficient measurement of heavy oil. A fast data-implementation procedure including specially designed 3D pulse sequence and Inversion Laplace Transform (ILT) algorithm was adopted to process the data and extract 3D T1-D-T2 probability function. It indicates that NMR relaxometry and diffusometry are useful to characterize the components of heavy oil samples. NMR results were compared with independent measurements of fractionation and gas chromatography analysis. 展开更多
关键词 Heavy oil multi-dimensional nmr unilateral sensor
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Laplace NMR谱图重建——从经典正则化到深度学习
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作者 杨钰 陈博 +3 位作者 吴柳滨 林恩平 黄玉清 陈忠 《波谱学杂志》 CAS 2024年第2期191-208,共18页
拉普拉斯核磁共振(Laplace NMR)可以提供待测样品的扩散系数或弛豫时间等物理参数信息,是用于研究分子化学结构、动力学和相互作用的强大工具.Laplace NMR的适用性很大程度上取决于拉普拉斯逆变换相关的信号处理算法的性能.在本文中,我... 拉普拉斯核磁共振(Laplace NMR)可以提供待测样品的扩散系数或弛豫时间等物理参数信息,是用于研究分子化学结构、动力学和相互作用的强大工具.Laplace NMR的适用性很大程度上取决于拉普拉斯逆变换相关的信号处理算法的性能.在本文中,我们首先讨论了Laplace NMR谱图重建问题的不适定性,接着回顾了经典的基于正则化约束的重建算法,并介绍了目前前沿的深度学习算法在处理Laplace反演问题方面的应用,最后总结了这些算法的优缺点,并对Laplace NMR信号处理方法未来改进方向进行了展望. 展开更多
关键词 拉普拉斯核磁共振 扩散核磁共振 扩散排序谱 拉普拉斯反演变换 深度学习
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应用于太赫兹波驱动的DNP-NMR传输线
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作者 王维 张澳歌 +4 位作者 宋韬 姚纳 焦蛟 张开春 刘頔威 《真空电子技术》 2024年第3期5-9,共5页
太赫兹波驱动的动态核极化增强核磁共振波谱系统可大幅提高信号灵敏度和缩短检测时间。该系统需采用传输线在驱动源回旋管与谱仪之间进行太赫兹波传输。本文针对400 MHz增强核磁共振系统设计了由准光模式变换器和波纹波导组成的太赫兹... 太赫兹波驱动的动态核极化增强核磁共振波谱系统可大幅提高信号灵敏度和缩短检测时间。该系统需采用传输线在驱动源回旋管与谱仪之间进行太赫兹波传输。本文针对400 MHz增强核磁共振系统设计了由准光模式变换器和波纹波导组成的太赫兹传输线,并进行了相关实验测试,测试结果表明准光模式变换器可将263 GHz回旋管TE 03模式转换成准高斯波束,其高斯成份为97%,整个传输线最终输出波束的高斯成份为96.3%。 展开更多
关键词 太赫兹 增强核磁共振 回旋管 传输线 准光模式变换
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Intelligent 6G Wireless Network with Multi-Dimensional Information Perception 被引量:1
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作者 YANG Bei LIANG Xin +3 位作者 LIU Shengnan JIANG Zheng ZHU Jianchi SHE Xiaoming 《ZTE Communications》 2023年第2期3-10,共8页
Intelligence and perception are two operative technologies in 6G scenarios.The intelligent wireless network and information perception require a deep fusion of artificial intelligence(AI)and wireless communications in... Intelligence and perception are two operative technologies in 6G scenarios.The intelligent wireless network and information perception require a deep fusion of artificial intelligence(AI)and wireless communications in 6G systems.Therefore,fusion is becoming a typical feature and key challenge of 6G wireless communication systems.In this paper,we focus on the critical issues and propose three application scenarios in 6G wireless systems.Specifically,we first discuss the fusion of AI and 6G networks for the enhancement of 5G-advanced technology and future wireless communication systems.Then,we introduce the wireless AI technology architecture with 6G multidimensional information perception,which includes the physical layer technology of multi-dimensional feature information perception,full spectrum fusion technology,and intelligent wireless resource management.The discussion of key technologies for intelligent 6G wireless network networks is expected to provide a guideline for future research. 展开更多
关键词 6G wireless network artificial intelligence multi-dimensional information perception full spectrum fusion
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烟草果胶和纤维素含量^(13)C MultiCP/MAS NMR同时测量
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作者 王鹏 唐杰 +5 位作者 杨明宇 朱立军 汪长国 陈昆燕 王鹏 杨俊 《安徽农业大学学报》 CAS CSCD 2024年第3期516-522,共7页
果胶和纤维素是烟草细胞壁的重要组成成分,其含量对烟草品质与安全性产生重要影响。传统分析方法难以实现果胶和纤维素的同时定量。本文在优化核磁共振波谱序列条件的基础上,采用固体^(13)C多重交叉极化/魔角旋转核磁共振波谱分析技术(^... 果胶和纤维素是烟草细胞壁的重要组成成分,其含量对烟草品质与安全性产生重要影响。传统分析方法难以实现果胶和纤维素的同时定量。本文在优化核磁共振波谱序列条件的基础上,采用固体^(13)C多重交叉极化/魔角旋转核磁共振波谱分析技术(^(13)C MultiCP/MAS NMR)建立了烟草果胶和纤维素含量的同时测量新方法。方法以聚半乳糖醛酸和微晶纤维素为标准物质,以3-(三甲基甲硅烷基)丙酸-d4钠盐(TMSP)做为内标物质,分别建立内标法标准曲线,相关系数R2为0.999 0和0.998 2。果胶测量的检出限和定量限分别为0.38和1.28 mg·g^(–1),精密度(RSD,n=5)小于3.05%。纤维素测量的检出限和定量限为1.01和3.32 mg·g^(–1),精密度(RSD,n=5)小于2.74%。应用本方法测量烟梗、烟草薄片和烟叶等不同类型样品中的果胶和纤维素含量,并对比烟草行业标准方法的测量结果,果胶含量的相对误差在-0.95%至4.51%之间,纤维素含量的相对误差在0.77%至2.46%之间。表明^(13)C MultiCP/MAS NMR方法快速,准确,适合批量样品的分析测量,为果胶和纤维素等细胞壁类大分子的同时定量分析提供重要技术支持。 展开更多
关键词 果胶 纤维素 ^(13)C MultiCP/MAS nmr 烟草
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Envelope Method and More General New Global Structures of Solutions for Multi-dimensional Conservation Law
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作者 Gui-Qin Qiu Gao-Wei Cao +1 位作者 Xiao-Zhou Yang Yuan-An Zhao 《Communications on Applied Mathematics and Computation》 2023年第3期1180-1234,共55页
For the two-dimensional(2D)scalar conservation law,when the initial data contain two different constant states and the initial discontinuous curve is a general curve,then complex structures of wave interactions will b... For the two-dimensional(2D)scalar conservation law,when the initial data contain two different constant states and the initial discontinuous curve is a general curve,then complex structures of wave interactions will be generated.In this paper,by proposing and investigating the plus envelope,the minus envelope,and the mixed envelope of 2D non-selfsimilar rarefaction wave surfaces,we obtain and the prove the new structures and classifications of interactions between the 2D non-selfsimilar shock wave and the rarefaction wave.For the cases of the plus envelope and the minus envelope,we get and prove the necessary and sufficient criterion to judge these two envelopes and correspondingly get more general new structures of 2D solutions. 展开更多
关键词 Riemann problem Non-selfsimilar shock wave Non-selfsimilar rarefaction wave ENVELOPE multi-dimensional conservation law
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Research and Practice on the Multi-dimensional Course Goal Achievement Evaluation of Software Engineering
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作者 Ying Jiang Hongbin Wang Jiaman Ding 《计算机教育》 2023年第12期265-271,共7页
According to the standards of engineering education accreditation,the achievement paths and evaluation criteria of course goals are presented,aimed at the objectives of software engineering courses and the characteris... According to the standards of engineering education accreditation,the achievement paths and evaluation criteria of course goals are presented,aimed at the objectives of software engineering courses and the characteristics of hybrid teaching in Kunming University of Science and Technology.Then a multi-dimensional evaluation system for course goal achievement of software engineering is proposed.The practice’s results show that the multi-dimensional course goal achievement evaluation is helpful to the continuous improvement of course teaching,which can effectively support the evaluation of graduation outcomes. 展开更多
关键词 Software engineering Course goal achievement evaluation multi-dimensional
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An Ordinal Multi-Dimensional Classification(OMDC)for Predictive Maintenance
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作者 Pelin Yildirim Taser 《Computer Systems Science & Engineering》 SCIE EI 2023年第2期1499-1516,共18页
Predictive Maintenance is a type of condition-based maintenance that assesses the equipment's states and estimates its failure probability and when maintenance should be performed.Although machine learning techniq... Predictive Maintenance is a type of condition-based maintenance that assesses the equipment's states and estimates its failure probability and when maintenance should be performed.Although machine learning techniques have been frequently implemented in this area,the existing studies disregard to the nat-ural order between the target attribute values of the historical sensor data.Thus,these methods cause losing the inherent order of the data that positively affects the prediction performances.To deal with this problem,a novel approach,named Ordinal Multi-dimensional Classification(OMDC),is proposed for estimating the conditions of a hydraulic system's four components by taking into the natural order of class values.To demonstrate the prediction ability of the proposed approach,eleven different multi-dimensional classification algorithms(traditional Binary Relevance(BR),Classifier Chain(CC),Bayesian Classifier Chain(BCC),Monte Carlo Classifier Chain(MCC),Probabilistic Classifier Chain(PCC),Clas-sifier Dependency Network(CDN),Classifier Trellis(CT),Classifier Dependency Trellis(CDT),Label Powerset(LP),Pruned Sets(PS),and Random k-Labelsets(RAKEL))were implemented using the Ordinal Class Classifier(OCC)algorithm.Besides,seven different classification algorithms(Multilayer Perceptron(MLP),Support Vector Machine(SVM),k-Nearest Neighbour(kNN),Decision Tree(C4.5),Bagging,Random Forest(RF),and Adaptive Boosting(AdaBoost))were chosen as base learners for the OCC algorithm.The experimental results present that the proposed OMDC approach using binary relevance multi-dimensional classification methods predicts the conditions of a hydraulic system's multiple components with high accuracy.Also,it is clearly seen from the results that the OMDC models that utilize ensemble-based classification algorithms give more reliable prediction performances with an average Hamming score of 0.853 than the others that use traditional algorithms as base learners. 展开更多
关键词 Machine learning multi-dimensional classification ordinal classification predictive maintenance
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Data inversion of multi-dimensional magnetic resonance in porous media
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作者 Fangrong Zong Huabing Liu +1 位作者 Ruiliang Bai Petrik Galvosas 《Magnetic Resonance Letters》 2023年第2期127-139,I0004,共14页
Since its inception in the 1970s,multi-dimensional magnetic resonance(MR)has emerged as a powerful tool for non-invasive investigations of structures and molecular interactions.MR spectroscopy beyond one dimension all... Since its inception in the 1970s,multi-dimensional magnetic resonance(MR)has emerged as a powerful tool for non-invasive investigations of structures and molecular interactions.MR spectroscopy beyond one dimension allows the study of the correlation,exchange processes,and separation of overlapping spectral information.The multi-dimensional concept has been re-implemented over the last two decades to explore molecular motion and spin dynamics in porous media.Apart from Fourier transform,methods have been developed for processing the multi-dimensional time-domain data,identifying the fluid components,and estimating pore surface permeability via joint relaxation and diffusion spectra.Through the resolution of spectroscopic signals with spatial encoding gradients,multi-dimensional MR imaging has been widely used to investigate the microscopic environment of living tissues and distinguish diseases.Signals in each voxel are usually expressed as multi-exponential decay,representing microstructures or environments along multiple pore scales.The separation of contributions from different environments is a common ill-posed problem,which can be resolved numerically.Moreover,the inversion methods and experimental parameters determine the resolution of multi-dimensional spectra.This paper reviews the algorithms that have been proposed to process multidimensional MR datasets in different scenarios.Detailed information at the microscopic level,such as tissue components,fluid types and food structures in multi-disciplinary sciences,could be revealed through multi-dimensional MR. 展开更多
关键词 multi-dimensional MR Data inversion Porous media Inverse Laplace transform FOURIERTRANSFORM
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NMR、GPC和MALDI-TOF应用于聚乙二醇单甲醚的教学实验
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作者 史声宇 刘智勇 +4 位作者 张宗瑞 相益信 沈显荣 宋庆平 高建纲 《广州化工》 CAS 2024年第10期129-131,共3页
将核磁共振(NMR)、凝胶渗透色谱(GPC)和基质辅助激光解吸/电离飞行时间质谱(MALDI-TOF)三种高级分析技术整合到本科《高分子材料研究方法》课程的实验教学中。通过分析聚乙二醇单甲醚样品,学生深入学习了高分子结构和分子量的表征方法,... 将核磁共振(NMR)、凝胶渗透色谱(GPC)和基质辅助激光解吸/电离飞行时间质谱(MALDI-TOF)三种高级分析技术整合到本科《高分子材料研究方法》课程的实验教学中。通过分析聚乙二醇单甲醚样品,学生深入学习了高分子结构和分子量的表征方法,熟悉了这三种仪器的操作和原理。本实验显著提升了课程内容的深度和广度,激发了学生的学习兴趣,并且增强了学生的实践操作能力和创新思维。综合应用这些分析技术,使学生在高分子材料的研究中获得了更全面的理解和技能的提升。 展开更多
关键词 高分子 核磁共振 凝胶渗透色谱 大分子质谱
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基于^(13)C-NMR偶极去相技术的有机肥料中有机组分特征研究
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作者 王林洋 张育维 +3 位作者 李亚丽 唐杉 谢丽华 汪洪 《植物营养与肥料学报》 CAS CSCD 北大核心 2024年第8期1630-1638,共9页
【目的】在固体13C-NMR的交叉极化魔角旋转全边带抑制(cross polarization/magic angle spinning/total suppression of sidebands,CP/MAS/TOSS)技术得到的谱图中,质子碳与非质子碳的信号重叠。偶极去相(dipolar dephasing,DD)技术利用1... 【目的】在固体13C-NMR的交叉极化魔角旋转全边带抑制(cross polarization/magic angle spinning/total suppression of sidebands,CP/MAS/TOSS)技术得到的谱图中,质子碳与非质子碳的信号重叠。偶极去相(dipolar dephasing,DD)技术利用13C-1H异核耦合作用大小的差异,区分与不同质子结合的13C核基团。本研究基于DD技术探讨有机肥料中碳结构特征。【方法】供试有机肥料样品包括3种秸秆(小麦秸秆、玉米秸秆、水稻秸秆)、3种粪肥(鸡粪、牛粪、猪粪)和3种腐植酸肥(腐植酸铵、腐植酸钠、腐植酸钾)样品,利用13C-NMR谱的CP/MAS/TOSS结合DD技术,测定了不同来源的有机肥料样品图谱,比较其碳分布比例。【结果】秸秆和粪肥样品中烷氧碳组分较多,占鉴定出所有碳组分的比例分别为55%和31%~37%,非质子化的烷氧碳占比不到3%;秸秆、猪粪样品中非质子芳香碳占3%~4%,鸡粪和牛粪样品中非质子芳香碳分别占15%和11%,较秸秆和猪粪样品含有更多的非质子化芳香族化合物。粪肥和秸秆样品中甲氧基碳占比低于烷基氮。腐植酸样品以芳香碳、羧基碳和酰胺基碳为主,羧基碳和酰胺基碳占到12%~16%,总芳香族碳占48%~72%,非质子芳香碳占25%~37%,表明腐植酸芳香骨架上可能存在较多取代。【结论】基于CP/TOSS结合DD技术(偶极相移延时时间设置为40μs)分析结果发现,鸡粪和牛粪中非质子芳香碳占比高于猪粪和秸秆;腐植酸肥芳香族碳比例高于粪肥和秸秆,尤其是非质子芳香碳占比较高,表明腐植酸肥芳香化程度高于粪肥和秸秆。 展开更多
关键词 有机肥料 ^(13)C-核磁共振 交叉极化 偶极去相
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基于小型化原子磁力计的零场NMR波谱仪搭建与测试
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作者 付方跃 郭清乾 +5 位作者 冯晓宇 徐佳玉 姚泽坤 胡涛 杨晓冬 常严 《波谱学杂志》 CAS 2024年第1期87-98,共12页
常规高场NMR波谱仪依托超导技术,其体积大、维护成本高,且存在样本磁化率不均匀导致的谱线展宽现象,零场或近零场NMR技术则可实现有效互补.本文自主搭建了一套基于小型原子磁力计的可移动零场NMR波谱仪,采用以多功能采集卡(National Ins... 常规高场NMR波谱仪依托超导技术,其体积大、维护成本高,且存在样本磁化率不均匀导致的谱线展宽现象,零场或近零场NMR技术则可实现有效互补.本文自主搭建了一套基于小型原子磁力计的可移动零场NMR波谱仪,采用以多功能采集卡(National Instruments PCIe-6353)为核心的集成控制系统,仪器主磁场强度小于1nT,可实现高分辨率的J-耦合谱采集.为实现对自旋体系的有效操控,利用样品绝热初态的单脉冲激发实现对三轴脉冲线圈的精确标定.在此基础上,使用改进的组合脉冲序列实现了在^(13)C-^(1)H异核体系下的单自旋选择性操控,验证了零场NMR波谱仪的有效性. 展开更多
关键词 零场核磁共振 J-耦合谱 原子磁力计 单自旋操控
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舒肝宁注射液的^(1)H-NMR指纹图谱分析
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作者 何峰 朱彤彤 +4 位作者 韩春月 张昀 杨翠萍 韩立峰 付志飞 《中南药学》 CAS 2024年第3期753-759,共7页
目的对舒肝宁注射液的^(1)H-NMR指纹图谱进行分析,为其质量控制标准技术升级提供参考依据。方法使用Noesygppr1d脉冲序列[recycle delay(RD)-90°-t 1-90°-t_(m)-90°-ACQ]采集1H-NMR谱图,质子共振频率为600.13 MHz,实验... 目的对舒肝宁注射液的^(1)H-NMR指纹图谱进行分析,为其质量控制标准技术升级提供参考依据。方法使用Noesygppr1d脉冲序列[recycle delay(RD)-90°-t 1-90°-t_(m)-90°-ACQ]采集1H-NMR谱图,质子共振频率为600.13 MHz,实验温度为298 K,通过方法学考察验证分析方法可靠性,采用相关系数法和夹角余弦法评价不同批次舒肝宁注射液样品的相似度。结果对舒肝宁注射液的^(1)H-NMR指纹图谱进行分析,共鉴定出88种化学成分,且不同批次的舒肝宁注射液具有较高的相似度。结论建立了一种基于^(1)H-NMR的舒肝宁注射液质量控制方法,可为舒肝宁注射液技术升级提供参考依据。 展开更多
关键词 舒肝宁注射液 1H-nmr 指纹图谱 相似度
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^(13)C NMR、FT-IR、Raman和建模技术对烟煤和无烟煤分子结构的应用研究
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作者 李元吉 代诚欣 +2 位作者 孟上九 张保勇 张强 《太原理工大学学报》 CAS 北大核心 2024年第6期1063-1072,共10页
【目的】探究高精度煤的结构演化及其机理的定量表征。【方法】通过显微组分鉴定、镜质体反射率、工业品质、元素分析和光谱分析,确定了烟煤(FS1)和无烟煤(ZY1)碳骨架结构、官能团的赋存状态等信息,并通过计算机辅助分子设计建立2个分... 【目的】探究高精度煤的结构演化及其机理的定量表征。【方法】通过显微组分鉴定、镜质体反射率、工业品质、元素分析和光谱分析,确定了烟煤(FS1)和无烟煤(ZY1)碳骨架结构、官能团的赋存状态等信息,并通过计算机辅助分子设计建立2个分子结构模型。【结果】结果表明,随着煤化作用的进行,烟煤到无烟煤过程中,亚甲基的损失速率比甲基的损失速率快,芳香性增强,芳香环的脂肪族链变短且支化度较高,含氧官能团逐渐减少,煤结晶程度增强,煤的化学结构趋于成熟稳定,且煤中的脂肪碳减少,芳香碳增加,甲基碳和亚甲基碳含量减少。经过多次尝试确定了芳香炭、脂肪族侧链和氧官能团之间的键合模式,获得最终的分子结构模型:C_(175)H_(162)O_(13)N_(2)(FS1)、C_(190)H_(159)O_(5)N_(3)(ZY1).该模型较好地反映煤的真实结构,模拟的^(13)C NMR光谱与实验光谱具有良好的一致性。上述研究为不同变质程度煤的分子结构演化提供了理论参考,为建立高可信度的分子结构表征提供了方法。 展开更多
关键词 ^(13)C nmr FT-IR RAMAN 分子结构模型
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基于LF-NMR研究双孢菇远红外辅助热泵干燥过程中水分迁移规律及品质变化
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作者 高晓倩 刘瑞玲 +4 位作者 吴来春 孟祥红 吴伟杰 陈杭君 郜海燕 《中国食品学报》 EI CAS CSCD 北大核心 2024年第8期403-413,共11页
为研究双孢菇远红外辅助热泵干燥过程中水分分布规律及品质变化,采用低场核磁共振及成像技术分别对干燥过程的双孢菇进行弛豫特性及质子密度成像分析,并研究干燥前、后双孢菇微观结构和品质的变化。结果表明:在热泵温度分别为45,55,65℃... 为研究双孢菇远红外辅助热泵干燥过程中水分分布规律及品质变化,采用低场核磁共振及成像技术分别对干燥过程的双孢菇进行弛豫特性及质子密度成像分析,并研究干燥前、后双孢菇微观结构和品质的变化。结果表明:在热泵温度分别为45,55,65℃时,双孢菇到达干燥终点的时间分别为510,420,390 min。双孢菇的T2反演谱有3个不同的弛豫峰:T21(3~23 ms)、T22(25~155 ms)和T23(155~1084 ms),分别代表双孢菇中的结合水、不易流动水和自由水。干燥初期,T23左迁幅度很大,干燥后期,左迁幅度变小,随着干燥时间的延长,自由水的流动性降低。干燥结束时,T23对应的弛豫峰下降约99.8%,只剩下部分T21和T22对应的峰,说明自由水几乎被完全去除,双孢菇内仅剩结合水和少量不易流动水。低场核磁共振图像显示,65℃条件下,干燥360 min,水分基本被脱除,而55℃和45℃处理组分别在干燥390 min和450 min才基本脱除。双孢菇外侧的水分先被脱除,内部的水分向外迁移,并且温度越高,内部水分迁移速率越快。另外,65℃条件下的双孢菇的BI值分别比45℃和55℃条件下的BI低30.55%和22.69%,说明65℃更能维持双孢菇原有的色泽。65℃条件下干燥的双孢菇的抗坏血酸、总酚、总黄酮含量分别比干燥前下降84.62%,55.80%和36.78%,与45℃和55℃相比,65℃下双孢菇营养成分的损失最小。本研究表明低场核磁共振及成像技术为双孢菇干燥过程中水分的变化提供了直观的参考依据,也可为双孢菇的远红外辅助热泵干燥工艺优化干燥参数、提高产品质量提供理论参考。 展开更多
关键词 双孢菇 远红外辅助热泵干燥 低场核磁共振 水分分布 品质
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Postmortem ^(7)Li NMR analysis for assessing the reversibility of lithium metal electrodes in lithium metal batteries
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作者 Jaewon Baek Sunha Kim +1 位作者 Hee-Tak Kim Oc Hee Han 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第7期430-440,共11页
Despite the proficiency of lithium(Li)-7 NMR spectroscopy in delineating the physical and chemical states of Li metal electrodes,challenges in specimen preparation and interpretation impede its progress.In this study,... Despite the proficiency of lithium(Li)-7 NMR spectroscopy in delineating the physical and chemical states of Li metal electrodes,challenges in specimen preparation and interpretation impede its progress.In this study,we conducted a comprehensive postmortem analysis utilizing ^(7)Li NMR,employing a stan-dard magic angle spinning probe to examine protective-layer coated Li metal electrodes and LiAg alloy electrodes against bare Li metal electrodes within Li metal batteries(LMBs).Our investigation explores the effects of sample burrs,alignment with the magnetic field,the existence of liquid electrolytes,and precycling on the ^(7)Li NMR signals.Through contrasting NMR spectra before and after cycling,we identi-fied alterations in Li^(0) and Li^(+) signals attributable to the degradation of the Li metal electrode.Our NMR analyses decisively demonstrate the efficacy of the protective layer in mitigating dendrite and solid elec-trolyte interphase formation.Moreover,we noted that Li*ions near the Li metal surface exhibit magnetic susceptibility anisotropy,revealing a novel approach to studying diamagnetic species on Li metal elec-trodes in LMBs.This study provides valuable insights and practical guidelines for characterizing distinct lithium states within LMBs. 展开更多
关键词 nmr spectroscopy Lithium-7 Lithium metal battery Electrolyte Electrode-protective layer Solid electrolyte interface Magnetic susceptibility anisotropy Lithium-metal nmr signal Diamagnetic^(7)Li nmr signal
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Multi-dimension and multi-modal rolling mill vibration prediction model based on multi-level network fusion
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作者 CHEN Shu-zong LIU Yun-xiao +3 位作者 WANG Yun-long QIAN Cheng HUA Chang-chun SUN Jie 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第9期3329-3348,共20页
Mill vibration is a common problem in rolling production,which directly affects the thickness accuracy of the strip and may even lead to strip fracture accidents in serious cases.The existing vibration prediction mode... Mill vibration is a common problem in rolling production,which directly affects the thickness accuracy of the strip and may even lead to strip fracture accidents in serious cases.The existing vibration prediction models do not consider the features contained in the data,resulting in limited improvement of model accuracy.To address these challenges,this paper proposes a multi-dimensional multi-modal cold rolling vibration time series prediction model(MDMMVPM)based on the deep fusion of multi-level networks.In the model,the long-term and short-term modal features of multi-dimensional data are considered,and the appropriate prediction algorithms are selected for different data features.Based on the established prediction model,the effects of tension and rolling force on mill vibration are analyzed.Taking the 5th stand of a cold mill in a steel mill as the research object,the innovative model is applied to predict the mill vibration for the first time.The experimental results show that the correlation coefficient(R^(2))of the model proposed in this paper is 92.5%,and the root-mean-square error(RMSE)is 0.0011,which significantly improves the modeling accuracy compared with the existing models.The proposed model is also suitable for the hot rolling process,which provides a new method for the prediction of strip rolling vibration. 展开更多
关键词 rolling mill vibration multi-dimension data multi-modal data convolutional neural network time series prediction
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Operando NMR methods for studying electrocatalysis
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作者 Zhiyu Zhu Ruipeng Luo Evan Wenbo Zhao 《Magnetic Resonance Letters》 2024年第2期54-64,共11页
The combination of electrochemical measurements with spectroscopic characterizations provides valuable insights into reaction mechanisms.Nuclear magnetic resonance(NMR)spectroscopy,as a powerful technique due to its a... The combination of electrochemical measurements with spectroscopic characterizations provides valuable insights into reaction mechanisms.Nuclear magnetic resonance(NMR)spectroscopy,as a powerful technique due to its atomic specificity and versatility in studying gas,liquid,and solid,allows the study of electrolyte solution,catalyst and catalyst-adsorbate interfaces.When applied in operando,NMR can offer molecular-level insights into various electrochemical processes.Operando NMR has been applied extensively in battery research,but relatively underexplored for electrocatalysis in the past two decades.In this mini review,we first introduce the operando electrochemical NMR setups,categorized by different probe designs.Then we review the applications of operando NMR for monitoring the electrolyte solution and the catalyst-adsorbate interface.Considering the high environmental impact of electrochemical conversion of CO_(2)into value-added products,we zoom in to the use of operando NMR in studying electrochemical CO_(2)reduction.Finally,we provide our perspective on further developing and applying operando NMR methods for understanding the complex reaction network of Cu-catalyzed electrochemical CO_(2)reduction. 展开更多
关键词 Operando nmr In situ nmr EC-nmr ELECTROCATALYSIS Electrochemical CO_(2)reduction
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Structural analysis of silk using solid-state NMR
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作者 Tetsuo Asakura 《Magnetic Resonance Letters》 2024年第3期19-34,共16页
Silkworms and spiders are capable of generating fibers that are both highly durable and elastic in a short span of time,using a silk solution stored within their bodies at room temperature and normal atmospheric press... Silkworms and spiders are capable of generating fibers that are both highly durable and elastic in a short span of time,using a silk solution stored within their bodies at room temperature and normal atmospheric pressure.The dragline silk fiber,which is essentially a spider's lifeline,surpasses the strength of a steel wire of equivalent thickness.Regrettably,humans have yet to replicate this process to produce fibers with similar high strength and elasticity in an eco-friendly manner.Therefore,it is of utmost importance to thoroughly comprehend the extraordinary structure and fibrillation mechanism of silk,and leverage this understanding in the manufacturing of high-strength,high-elasticity fibers.This review will delve into the recent progress in comprehending the structure of silks derived from silkworms and spiders,emphasizing the distinctive attributes of solidstate NMR. 展开更多
关键词 SILK Bombyx mori SPIDER Solid-state nmr STRUCTURE
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