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氯化钇阳离子膜电解制备Y(OH)_(3)并热处理合成Y_(2)O_(3)

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中国稀土学报 2024年第4期42卷 790-800,I0005页

作者：洑阳成真林胜男徐太宇张峰张廷安东北大学冶金学院辽宁沈阳024110

通过电化学方法制备稀土氧化物在环保和经济上极具优势,阳离子交换膜电解氯化稀土转化技术还未应用于Y_(2)O_(3)的制备过程,对于YCl_(3)转化过程的参数和优化方法仍不清楚。本研究以氯化钇水溶液为原料通过阳离子交换膜电解技术,在阴极... 详细信息

通过电化学方法制备稀土氧化物在环保和经济上极具优势,阳离子交换膜电解氯化稀土转化技术还未应用于Y_(2)O_(3)的制备过程,对于YCl_(3)转化过程的参数和优化方法仍不清楚。本研究以氯化钇水溶液为原料通过阳离子交换膜电解技术,在阴极得到了片层状Y(OH)_(3)沉积物。用DSC-TG,FTIR和XRD研究了Y(OH)_(3)的热分解过程,得到了继承前驱体结构的Y_(2)O_(3)产物。使用SEM和XRD测试了不同极距、阴极钇离子浓度、电流密度、温度对电解产物的晶体和形貌的影响。得到最佳实验条件为:5 cm极距、0.025 mol·L^(-1)阴极钇离子浓度、31.3 mA·cm^(-2)电流密度和55℃电解温度下,产物具有最好的形貌和粒子结构。

关键词：离子交换膜电解 Y(OH)_(3) Y_(2)O_(3) 水溶液电解稀土

TREND OF PRECIPITATION VARIATION IN HUBEI PROVINCE SINCE THE 1960S

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Chinese Geographical Science 2003年第4期13卷 322-327页

作者： chenzheng-hong QINJun HubeiInstituteofMeteorologicalScience＆Technology Wuhan430074P.R.China NanjingInstituteofMeteorology.Nanjing430074 P.R.China

Through linear regression analysis to the trend of annual,seasonal and monthly precipitation of 72 meteorological stations in Hubei Province from 1961 to 1995,it is revealed that: 1) annual precipitation was increasing by 61.0mm/10a in the eastern part of Hubei (112°E as a dividing line) and decreasing by 34.9mm/10a in the western part; 2) precipitation in winter and summer (January,February,March,June and July) was increasing in almost whole province which usually with non-uniformity of precipitation distribution from the south to the north. The precipitation in spring,autumn and winter (April,September,November and December) was decreasing in most of the areas which usually with non-uniformity of precipitation distribution from the east to the west. March and December were transition periods between two spatial distribution patterns mentioned above; 3) the eastern part of Hubei has beome one of precipitation increasing centers in China. The results was consistent with the trend that more frequent flood and drought events happened in Hubei Province which are more different in spatial and temporal scales.

关键词： bias of precipitation temporal and spatial differences Hubei province

慢特征分析引导的多级注意力自编码器遥感图像变化检测

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测绘通报 2024年第9期 67-73页

作者：刘金玲陈红珍李辰征聂宏宾李立钢中国科学院国家空间科学中心复杂航天系统电子信息技术重点试验室北京100190 中国科学院大学计算机科学与技术学院北京100049

遥感图像变化检测是识别和量化地表变化的一种重要途径,是遥感技术的主要应用之一。然而在不同光照、季节等成像条件下获取的遥感图像中,同一物体会表现出不同的外观,使得变化检测算法难以准确判别真实地表变化。针对此问题,提出了基于... 详细信息

遥感图像变化检测是识别和量化地表变化的一种重要途径,是遥感技术的主要应用之一。然而在不同光照、季节等成像条件下获取的遥感图像中,同一物体会表现出不同的外观,使得变化检测算法难以准确判别真实地表变化。针对此问题,提出了基于慢特征分析引导的多级注意力自编码器(SFAMAA)遥感图像变化检测方法。首先,设计了一种U型卷积自编码器并引入多级通道注意力机制,扩大网络感受野的同时使其聚焦重要通道的信息,增强网络对全局信息和变化信息的感知能力;然后,设计了一种慢特征分析损失函数引导网络训练,使得网络可以有效抑制因成像条件差异导致的伪变化。在公开数据集SZTAKI上进行试验验证,试验结果表明,本文方法可有效抑制噪声和伪变化,对不同光照、季节等成像条件下获取的遥感图像具有较高的精度和良好的稳健性。

关键词：自编码器通道注意力慢特征分析变化检测

Computer Simulation of Ordering and Atom Clustering in Aging Binary Al-Li Alloy

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材料热处理学报 2004年第5B期25卷 720-723页

作者： LIXiao-ling chenzheng WANGYong-xin HUMing-juan DepartmentofMaterialScienceandEngineering ShanghaiJiaoTongUniversityShanghaiChina DepartmentofMaterialScienceandEngineering NorthwesternPolytechnicalUniversityXi＇anChina

Ordering and atom clustering in aging binary Al-Li alloy has been investigated by computer simulation through calculating the long range order (Iro.) parameter and composition deviation order parameter from single-site occupation probabilities of Li atom. The results show that when the alloy lies in metastable region in the phase diagram ordering and atom clustering occur simultaneously. As the composition of the alloy increases ordering occurs earlier than atom clustering gradually. When the alloy lies in instable region atom clustering takes place after the congruent ordering completes. It has also been found that the incubation period of the phase transformation is shortened as the composition increases.

关键词：计算机模拟有序化原子偏聚 Al-Li合金

Enhanced Nonlinear Optical Properties of Laser Deposited Ag／BaTiO3 Nanocomposite Films

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Chinese Physics Letters 2003年第6期20卷 924-927页

作者： YANGGuang WANGWei-Tian YANGGuo-Zhen chenzheng-Hao LaboratoryofOpticalPhysics InstituteofPhysicsandCenterforCondensedMatterPhysicsChineseAcademyofSciencesBeijing100080

The composite films containing Ag particles embedded in BaTiO3 matrix were deposited on MgO (100) substrates by using the pulsed laser deposition technique and characterized by x-ray diffraction and x-ray photoelectron spectroscopy. The absorption peak resulting from the surface plasmon resonance of Ag particles is found at the wavelength of 430 nm. The third-order nonlinear optical characteristics of the films are determined by z-scan technique using a nanosecond laser. The results show that the Ag/BaTiO3 nanocomposite films exhibit great optical nonlinearities and the real and imaginary parts of the third-order nonlinear susceptibility X(3) are calculated to be 4.544 x 10-6 esu and 2.352 x 10-7 esu, respectively. The enhancement mechanism of X(3) is discussed.

关键词： Nanocomposite films

NUMERICAL SIMULATION OF 3-D REAERATION IN BODY-FITTED COORDINATE SYSTEM

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Journal of Hydrodynamics 2003年第4期15卷 92-97页

作者： FangXiang-wei ChenGang ShenChun-ni chenzheng-han LiJian-zhong DepartmentofMilitaryCivilEngineering LongisticalEngineeringUniversityChongqing400041China InstituteofwaterResourcesand.HydroelectricEngineering Xi‘anUniversityofTechnologyXi’an710048China InstituteofwaterResourcesandHydroelectricEngineering .Xi‘anUnversityofTechnologyXi’an710048China

A three-dimensional numerical model was developed to simulate reaerationusing a body-fitted coordinate system. The model was designed to calculate the velocity and oxygenconcentration separately, called, 'no pairing resolution'. The velocity was calculated by SIMPLECalgorithm in the body-fitted coordinate system. The considerably proposed model was checked by areaeration experiment couducted in an open channel. The computed results agree considerably wellwith the experimental data. The model was also used to predict the reaeration in an S-shapedchannel, and the numerical results are discussed.

关键词： reaeration turbulent model numerical simulation concentration field

Computer simulation of interface evolution for an Al-Li alloy during early aging stage

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Rare Metals 2004年第3期23卷 279-285页

作者： TANGLiying WANGYongxin chenzheng LUYanli ZHANGJianjun DepartmentofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXi＇an710072China DepartmentofMaterialsScienceandEngineering NorthwesternPolytechnicalUniversityXi＇an710072China

The nucleation of ordered phase was simulated based on microscopic diffusionequation and the assumptions of the classical nucleation theory were examined. The quantitativecalculations of interface thickness evolution were accomplished for the first time. It was foundthat the interfaces between ordered phase and disordered matrix were diffuse. The interfacethickness decreased with time, from the initial 1.2 nm to an equilibrium value 0.6 nm. The ratios ofthe radius of ordered particles and the interface thickness monotonously increased, but they wereof the same order of magnitude all the time. The sharp interface assumption should not be adopted inthis stage. For the Al-10% Li (atom fraction) alloy aged at 192℃, the assumptions of the classicalnucleation theory disagreed with the facts. The phase transformation followed the non-classicalnucleation mechanism and the applicable scope of the classical nucleation should be confined.

关键词： metal material interface computer simulation non-classical nucleationtheory

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六氟丁二烯的制备工艺研究进展

有机氟工业 2024年第1期 23-27页

作者：陈芳夏秋阳王昊朱建秀杜晨峥中化化工科学技术研究总院有限公司北京100083 中国国际工程咨询有限公司北京100048 中国中煤能源集团有限公司北京100120

六氟丁二烯因其刻蚀精准、绿色环保等优势而备受关注,成为新一代电子刻蚀气体的理想产品。目前已报道的六氟丁二烯制备路线复杂多样,以现有制备方法中涉及到的关键中间体为分类标准对当前主流制备工艺进行归纳,并对现阶段取得的进展展... 详细信息

六氟丁二烯因其刻蚀精准、绿色环保等优势而备受关注,成为新一代电子刻蚀气体的理想产品。目前已报道的六氟丁二烯制备路线复杂多样,以现有制备方法中涉及到的关键中间体为分类标准对当前主流制备工艺进行归纳,并对现阶段取得的进展展开论述。在此基础上,总结主流制备工艺存在的问题并展望未来可行的技术研发方向。

关键词：六氟丁二烯制备工艺电子气体刻蚀关键中间体

Synthesis of serotonin transporter imaging agent [^(125)I]ADAM

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Nuclear Science and Techniques 2005年第3期16卷 153-155页

作者： LUChun-Xiong WUChun-Ying JIANGQuan-Fu chenzheng-Ping ZHANGTong-Xing LIXiao-Ming WANGSong-Pei JiangsuInstituteofNuclearMedicine Wuxi214063

The synthesis of serotonin transporter imaging agent [125I] -2-((2-((dimethylamino)methyl)phenyl) thio)-5-iodophenylamine([125I] ADAM) was reported. The chemical structure of the labeling precursor 5- (tributyl- stannyl) -2-((2-((dimethylamino)methyl)phenyl)thio)phenylamine and all its intermediates were verified by IR,1HNMR and MS. The radioiodinated compound was prepared using iododestannylation reaction by hydrogen peroxide. Final radiochemical purity was above 95% determined by TLC.

关键词：复合胺传输成象介质 TLC 合成工艺放射医学