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ⅢA-ⅡB multicomponent perovskite rare earth ferrites with promising electromagnetic wave absorption properties

Journal of Rare Earths 2024年第6期42卷 1118-1127,I0005页

作者： Yanyan He Tao chen yanyu Pan Minzhong Huang Kaixian Wang Liyan Xue Yazhu Li Fengzhi Tan Fan Yang Tongkuan Xu Heng chen School of Light Industry and Chemical Engineering Dalian Polytechnic UniversityDalian116034China Xiamen Institute of Rare EarthMaterials Haixi InstitutesChinese Academy of SciencesXiamen36021China Fujian Institute of Research on the Structure of Matter Chinese Academyof SciencesFuzhou350002China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou350108China Xiamen Key-Laboratoryof Rare Earth Photoelectric Functional Materials Xiamen Institute of Rare Earth MaterialsHaixi InstituteChinese Academy of SciencesXiamen361021China Key Laboratory of Rare Earths Ganjiang Innovation AcademyChinese Academy of SciencesGanzhou3410ooChina

Perovskite-type rare-earth ferrites(REFeO_(3))are promising materials for absorbing electromagnetic(EM)wave pollution.However,insufficient dielectric loss and poor impedance matching are key factors that limit the broader implementation of REFeO_(3).Herein,a series of multicomponent perovskite-type ferrites with strong EM wave absorption capabilities was prepared.Through the synergistic effect of chemical constitution regulation and entropy regulation,optimization of the dielectric loss and impedance matching is achieved by strengthening the structural defect mechanism,thus further adjusting the EM wave absorption performance.Compared with(LaGdSmNdBa)FeO_(3)(HE-1)and(LaGdPrSmNdBa)FeO_(3)(HE-2),(LaGdBa)FeO_(3)(ME-1)and(LaGdSmBa)FeO_(3)(ME-2)exhibit favorable performance,with optimal minimum reflection loss(RL_(min))of-56.35 dB(at 11.12 GHz)and-63.25 dB(at 7.22 GHz)and effective absorption bandwidth(EAB)of 4.46 and 4.72 GHz,respectively.This multicomponent design provides a new strategy for the development of EM wave absorption materials.

关键词： Rare earths Multicomponent design Rare earth ferrites Entropy regulation Electromagnetic wave absorption

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High-entropy rare earth stannate ceramics:Acid corrosion resistant radiative cooling materials with high atmospheric transparency window emissivity and high near-infrared solar reflectivity

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Journal of Advanced Ceramics 2024年第5期13卷 630-640页

作者： Tao chen Yanyan He yanyu Pan Kaixian Wang Minzhong Huang Liyan Xue Yazhu Li Fan Yang Yanchun Zhou Heng chen Fujian Institute of Research on the Structure of Matter Chinese Academy of SciencesFuzhou 350002China College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350117China Xiamen Institute of Rare Earth Materials Haixi InstitutesChinese Academy of SciencesXiamen 361021China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials Xiamen Institute of Rare Earth MaterialsHaixi InstitutesChinese Academy of SciencesXiamen 361021China Key Laboratory of Rare Earths Ganjiang Innovation AcademyChinese Academy of SciencesGanzhou 341000China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

In response to the development of the concepts of“carbon neutrality”and“carbon peak”,it is critical to developing materials with high near-infrared(NIR)solar reflectivity and high emissivity in the atmospheric transparency window(ATW;8–13μm)to advance zero energy consumption radiative cooling technology.To regulate emission and reflection properties,a series of high-entropy rare earth stannate ceramics(HE-RE_(2)Sn_(2)O_(7):(Y_(0.2)La_(0.2)Nd_(0.2)Eu_(0.2)Gd_(0.2))_(2)Sn_(2)O_(7),(Y_(0.2)La_(0.2)Sm_(0.2)Eu_(0.2)Lu_(0.2))_(2)Sn_(2)O_(7),and(Y_(0.2)La_(0.2)Gd_(0.2)Yb_(0.2)Lu_(0.2))_(2)Sn_(2)O_(7))with severe lattice distortion were prepared using a solid phase reaction followed by a pressureless sintering method for the first time.Lattice distortion is accomplished by introducing rare earth elements with different cation radii and mass.The as-synthesized HE-RE_(2)Sn_(2)O_(7)ceramics possess high ATW emissivity(91.38%–95.41%),high NIR solar reflectivity(92.74%–97.62%),low thermal conductivity(1.080–1.619 W·m^(−1)·K^(−1)),and excellent chemical stability.On the one hand,the lattice distortion intensifies the asymmetry of the structural unit to cause a notable alteration in the electric dipole moment,ultimately enlarging the ATW emissivity.On the other hand,by selecting difficult excitation elements,HE-RE_(2)Sn_(2)O_(7),which has a wide band gap(Eg),exhibits high NIR solar reflectivity.Hence,the multi-component design can effectively enhance radiative cooling ability of HE-RE_(2)Sn_(2)O_(7)and provide a novel strategy for developing radiative cooling materials.

关键词： radiative cooling materials high-entropy ceramics(HECs) rare earth stannate(RE_(2)Sn_(2)O_(7)) high atmospheric transparency window emissivity high near-infrared(NIR)solar reflectivity

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Gemological-Mineralogical Characteristic of Spinels from Sri Lanka

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宝石和宝石学杂志（中英文） 2023年第6期25卷 42-57页

作者： Pantaree Lomthong Dietmar Schwarz Gamini Zoyza yanyu chen Yicen Liu Asian Institute of Gemological Sciences Shenzhen 518038China Zmpery Gemology Lab. Shanghai 201403China Ceylon Gemmological Services Colombo 01400Sri Lanka Lab.of Gems&Technological Materials of Tongii University Shanghai 200092China

Detailed mineralogical and gemological records were conducted on 340 unheated spinels from the Horana, Eheliyagoda, Ratnapura, and Okkampatiya mining areas in Sri Lanka. The color of Sri Lankan spinel varies greatly: in addition to the mainstream pink to purple pink, green and blue can also be seen. Compared with spinel from other regions such as Myanmar, Vietnam, and Tanzania, Sri Lanka's spinel has more abundant inclusions: several mining areas generally have inclusions such as dolomite, apatite, zircon, and chondrodite. Minerals such as graphite and forsterite are also found in spinel produced in the Horana region;graphite and rutile have been found in spinel produced in the Okkamptiya region. Partially healed fissures are most common in spinel in the Okkampatiya mining area;Unlike Vietnamese spinel, dislocations and growth structures are almost absent in Sri Lankan spinel. The LA-ICP-MS analysis results showed that there were no significant differences among the mining areas. LA-ICP-MS analysis of 5 Sri Lankan cobalt blue spinels showed a variation of 11 to 120 ppm in this chromogenic element. The UV visible absorption spectrum results show that Sri Lankan spinel has a combination spectra with variable ratios of the spectral components Cr 3+ , V 3+ and Fe 2+ from pink to red, orange, purple to purple, and blue-green. The results of infrared spectroscopy and laser Raman spectroscopy analysis showed that all samples showed no indications for heat treatment.

关键词： gemological-mineralogical characteristic spinel Sri Lanka spectroscopy inclusion

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Synthesis of Clionastatins A and B through Enhancement of Chlorination and Oxidation Levels of Testosterone

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Chinese Journal of Chemistry 2022年第23期40卷 2747-2755页

作者： Hao Cui Yang Shen Ruifeng Wang Haoxiang Wei Xin Lei yanyu chen Pengfei Fu Haoxiang Wang Ruihao Bi Yandong Zhang Department of Chemistry and Key Laboratory of Chemical Biology of Fujian Province iChEMCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamenFujian 361005China

A full account of semisyntheses of polychlorinated marine steroids clionastatins A and B is described.We have developed a unique two-stage chlorination-oxidation strategy that enabled concise and divergent semisyntheses of clionastatins A and B in 16 steps from inexpensive testosterone.Key transformations in chlorination stage include(a)conformationally controlled,stereospecific dichlorination through an unusualβ-chloronium intermediate to install the diequatorial C1,C2-dichloride;(b)C4-OH directed C19–H oxygenation followed by challenging neopentyl chlorination to install the C19–Cl.The high oxidation level was constructed through(a)the desaturation at C6–C7 through one-pot photochemical dibromination–reductive debromination;(b)regioselective anti-Markovnikov oxidation of the C6–C7 double bond by photoredox-metal dual catalysis to forge the B ring enone;(c)late-stage desaturation with SeO_(2)to introduce C8–C9 double bond.Wharton transposition was used to forge the D-ring enone,and thermodynamically driven epimerization secured the cis-fused C/D ring system.Furthermore,we also provided a 14-step approach to clionastatin A by optimizing the construction of the D-ring enone with a dehydration-oxidation sequence.

关键词： Steroids Semisynthesis Chlorination Oxidation Photochemistry

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计及界面电荷和极性效应的油纸复合绝缘非线性电路等效模型

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电工技术学报 2024年第11期39卷 3422-3432页

作者：黄猛李怡然吴延宇陈良炯齐波新能源电力系统全国重点实验室(华北电力大学) 北京102206

换流变压器是特高压直流输电工程中的关键设备,换流变压器油纸复合绝缘的界面处在直流电压下易积聚电荷,诱发局部放电甚至击穿。当前对于界面电荷的积聚分布,多采用传统的阻容模型进行计算,存在较大的误差。该文提出一种简易的非线性电... 详细信息

换流变压器是特高压直流输电工程中的关键设备,换流变压器油纸复合绝缘的界面处在直流电压下易积聚电荷,诱发局部放电甚至击穿。当前对于界面电荷的积聚分布,多采用传统的阻容模型进行计算,存在较大的误差。该文提出一种简易的非线性电路等效模型,首先,分别测量变压器油和油浸纸板的电容、电阻参数与极化电流,获得油纸的拓展Debye模型;其次,在拓展Debye模型的基础上,将变压器油和油浸纸板的恒定电阻模型改为随电场变化的非线性模型,并加入反映极性效应的界面势垒限制电流源,以此建立等效模型;最后,将电路等效模型仿真结果与实际测量结果进行对比。结果表明,与实际测量结果相比,该等效模型具有良好的适用性。该文模型为油纸绝缘的电场分布、界面电荷积聚量的计算提供了一种准确度较高的简便方法。

关键词：油纸绝缘界面电荷界面极化拓展Debye模型电路等效模型

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金属间化合物Pt_(7)Sb投影Berry相位与析氢催化关联的第一性原理计算

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金属学报 2024年第6期60卷 837-847页

作者：周彦余李江旭刘晨赖俊文高强马会孙岩陈星秋中国科学院金属研究所沈阳材料科学国家研究中心沈阳110016 中国科学技术大学材料科学与工程学院沈阳110016

高效催化材料的设计是能源材料领域的重要任务之一。本工作根据寻找具有低Pt负载量的高效析氢反应(HER)催化剂的指导原则,结合投影Berry相位描述符,设计发现了性能优异的HER催化剂立方Pt_(7)Sb,其氢吸附Gibbs自由能(ΔG_(H^(*)))甚至小... 详细信息

高效催化材料的设计是能源材料领域的重要任务之一。本工作根据寻找具有低Pt负载量的高效析氢反应(HER)催化剂的指导原则,结合投影Berry相位描述符,设计发现了性能优异的HER催化剂立方Pt_(7)Sb,其氢吸附Gibbs自由能(ΔG_(H^(*)))甚至小于Pt元素。因此,在降低Pt负载量的情况下,其HER催化活性有望提高。从电子结构分析来看,2个描述符ΔG_(H^(*))和投影Berry相位之间有很好的一致性。由于投影Berry相位完全由体态(波函数相位)决定,这种一致性意味着良好的催化性能与本征电子结构的拓扑性质之间存在着密切的关系。该结果提供了一个很好的HER催化剂候选材料,降低了Pt的负载量,并为展示催化剂本征拓扑性质的作用提供了参考。

关键词：析氢反应催化剂投影Berry相位第一性原理计算

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高判别精度的区块链交易合法性检测方法

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计算机工程与应用 2024年第5期60卷 271-280页

作者：蔡元海宋甫元黎凯陈彦宇付章杰南京信息工程大学数字取证教育部工程研究中心南京210044 西安电子科技大学综合业务网理论及关键技术国家重点实验室西安710071

区块链上的交易合法性检测对于加密数字货币的监管具有重大意义。针对现有交易合法性检测方法存在的检测精度低下、判别过程中难以有效兼顾交易本身信息与前后拓扑信息的问题,提出融合可信深度森林的多角度高精度合法性检测方法。设计... 详细信息

区块链上的交易合法性检测对于加密数字货币的监管具有重大意义。针对现有交易合法性检测方法存在的检测精度低下、判别过程中难以有效兼顾交易本身信息与前后拓扑信息的问题,提出融合可信深度森林的多角度高精度合法性检测方法。设计基于可信生成特征的可信深度森林TForest,以特征重排序的方式赋予子样本足够的区分度,结合可变滑动窗口以均衡无混淆的方式提取可信子样本,在大幅度降低生成特征维度的基础上,提高了深度森林的判别精度。提出一种集成策略,基于不同基模型对于正负样本识别能力的差异性,采用双阶段逐层优化的方式有效融合可信深度森林与Transformer图网络及残差网络三类基判别器,兼顾两方面信息,构成高精度的多角度分析模型T2Rnet。在Elliptic数据集上的实验结果显示,该模型的F1-score达到83.11%,相比基准图卷积方法提升31.6%,具备可靠的交易合法性检测性能。

关键词：区块链合法性检测可信深度森林神经网络双阶段集成

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流产后关爱护理干预改善人工流产术后患者睡眠质量的效果研究

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世界睡眠医学杂志 2024年第4期11卷 810-812页

作者：陈燕玉福建省宁德师范学院附属宁德市医院宁德352100

目的:分析流产后关爱护理干预改善人工流产术后患者生命质量与睡眠质量的效果。方法:选取2022年1月至2023年6月宁德师范学院附属宁德市医院收治的人工流产术患者100例作为研究对象,按照随机数字表法分为对照组和观察组,每组50例。对照... 详细信息

目的:分析流产后关爱护理干预改善人工流产术后患者生命质量与睡眠质量的效果。方法:选取2022年1月至2023年6月宁德师范学院附属宁德市医院收治的人工流产术患者100例作为研究对象,按照随机数字表法分为对照组和观察组,每组50例。对照组给予常规护理干预,观察组在对照组基础上给予关爱护理干预,采用健康调查简表(SF-36)比较2组患者干预前后生命质量的变化,采用匹兹堡睡眠质量指数(PSQI)比较2组患者干预前后睡眠质量的变化,并比较2组患者的失眠发生率。结果:干预后,2组SF-36评分均有升高,且观察组显著高于对照组,差异有统计学意义(P<0.05);干预后,2组PSQI评分均有降低,且观察组显著低于对照组,差异有统计学意义(P<0.05)。结论:流产后关爱护理干预在人工流产术中的应用能显著提升患者生命质量与睡眠质量,综合性护理价值高。

关键词：妊娠人工流产术流产后关爱护理干预生命质量睡眠质量匹兹堡睡眠质量指数

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Data fusion and machine learning for ship fuel efficiency modeling:Part Ⅱ-Voyage report data,AIS data and meteorological data

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Communications in Transportation Research 2022年第1期2卷 222-243页

作者： Yuquan Du yanyu chen Xiaohe Li Alessandro Schonborn Zhuo Sun Centre for Maritime and Logistics Management Australian Maritime CollegeUniversity of TasmaniaLauncestonTAS 7250Australia Institute for Marine and Antarctic Studies College of Sciences and EngineeringUniversity of TasmaniaTaroonaTAS 7053Australia College of Power and Energy Engineering Harbin Engineering UniversityHarbin150001China Maritime Energy Management World Maritime UniversityFiskehamnsgatan 120124 MalmoSweden College of Transportation Engineering Dalian Maritime UniversityDalian116026China

When voyage report data is utilized as the main data source for ship fuel efficiency analysis,its information on weather and sea conditions is often regarded as unreliable.To solve this issue,this study approaches AIS data to obtain the ship's actual detailed geographical positions along its sailing trajectory and then further retrieve the weather and sea condition information from publicly accessible meteorological data sources.These more reliable data about weather and sea conditions the ship sails through is fused into voyage report data in order to improve the accuracy of ship fuel consumption rate models.Eight 8100-TEU to 14,000-TEU containerships from a global shipping company were used in experiments.For each ship,nine datasets were constructed based on data fusion and eleven widely-adopted machine learning models were tested.Experimental results revealed the benefits of fusing voyage report data,AIS data,and meteorological data in improving the fit performances of machine learning models of forecasting ship fuel consumption rate.Over the best datasets,the performances of several decision tree-based models are promising,including Extremely randomized trees(ET),AdaBoost(AB),Gradient Tree Boosting(GB)and XGBoost(XG).With the best datasets,their R^(2) values over the training sets are all above 0.96 and mostly reach the level of 0.99-1.00,while their R^(2) values over the test sets are in the range from 0.75 to 0.90.Fit errors of ET,AB,GB,and XG on daily bunker fuel consumption,measured by RMSE and MAE,are usually between 0.8 and 4.5 ton/day.These results are slightly better than our previous study,which confirms the benefits of adopting the actual geographical positions of the ship recorded by AIS data,compared with the estimated geographical positions derived from the great circle route,in retrieving weather and sea conditions the ship sails through.

关键词： Ship fuel efficiency Fuel consumption rate Voyage report AIS Data fusion Machine learning

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非球面透镜模压退火影响因素及其优化仿真研究

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科技通报 2024年第6期40卷 25-31,56页

作者：陈庆张彦宇湖南铁道职业技术学院湖南株洲412001 湖南石油化工职业技术学院湖南岳阳414011

退火过程是光学玻璃模压的一个重要过程,影响退火过程的因素主要有退火速度、保持力及保持时间等因素。本文采用有限元仿真的方法,结合正交方法详细分析了退火过程中主要的3个工艺参数对非球面透镜退火过程的影响,最后通过灰色关联分析... 详细信息

退火过程是光学玻璃模压的一个重要过程,影响退火过程的因素主要有退火速度、保持力及保持时间等因素。本文采用有限元仿真的方法,结合正交方法详细分析了退火过程中主要的3个工艺参数对非球面透镜退火过程的影响,最后通过灰色关联分析来获取多目标的工艺参数优化,获得了各工艺参数的最优组合。

关键词：非球面透镜退火优化分析

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