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Stress and optical constants in thin films of BaF₂-PrF₃: A potential Th-free infrared low-index evaporation material

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OPTIK 2018年 173卷 174-179页

作者： Lva, xuwen Zheng, Weimin Xie, Ping li, Bin He, Weixiang Jing, Chao liu, Dingquan Shanghai Univ Dept Phys Shanghai 200444 Peoples R China Shandong Univ Sch Space Sci & Phys Weihai 264209 Peoples R China Chinese Acad Sci Shanghai Inst Tech Phys Shanghai 200083 Peoples R China Shanghai Tech Univ Sch Phys Sci & Technol Shanghai 200031 Peoples R China

Although PrF3 can be regarded as a potential infrared low-index evaporation material used in infrared antireflection to substitute for radioactive ThF4 because its thin films have a good transparency, the lower refractive index n and extinction coefficient k in the spectral range of thermal infrared, the greater tensile stress emerging in its layers will deteriorate the reliability and durability of antireflection coatings. In our investigation, BaF2-PrF3 thin films were deposited using electron beam evaporation from the sintered pellets of PrF3 admixed with BaF2. Stress in thin films was calculated from Stoney's equation on the basis of measuring the changes of radius of curvature of thin silicon strips. The stoichiometry of thin films was determined using the energy dispersive X-ray analysis (EDX). The optical constants of thin films were determined by fitting the measured spectral transmittance curves using Lorentz oscillators as a dispersion model. It can be observed that stress in BaF2-PrF3 thin films is obviously reduced with the increasing of the concentration of BaF2 in thin films and the sintered pellets. Moreover, it was also demonstrated that incorporation of BaF2 into PrF3 can reduce the refractive index of thin films, although BaF2-PrF3 thin films have a greater dispersion than that of PrF3 thin films. In addition, the lower value of extinction coefficient is also presented in thin films, like those of rare-earth fluorides.

关键词： Antireflection coatings Infrared Praseodymium fluoride Barium fluoride Electron beam evaporation Stress Optical constant

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High Q and high gradient performance of the first medium-temperature baking 1.3 GHz cryomodule

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Physical Review Accelerators and Beams 2024年第9期27卷 092003页

作者： Weimin Pan Jiyuan Zhai Feisi He Rui Ge Zhenghui Mi Peng Sha Song Jin Ruixiong Han Qunyao Wang Haiying lin Guangwei Wang xuwen Dai Zhanjun Zhang Mei li Minjing Sang liangrui Sun Rui Ye Tongxian Zhao Shaopeng li Keyu Zhu Baiqi liu Xiaolong Wang Xiangchen Yang Xiaojuan Bian Xiangzhen Zhang Huizhou Ma Jianbing Zhao liang Zhang Hui Zhao Runbing Guo Zhihui Mu Conglai Yang Xiaobing Zheng Chao Dong Hongjuan Zheng Zhengze Chang Xiaochen Yang Tongming Huang Qiang Ma Zihan Wang Ming liu Wenzhong Zhou Senyu Chen Chinese Academy of Sciences Beijing 100049 China Beijing 100049 China

The world’s first 1.3 GHz cryomodule containing eight 9-cell superconducting radio-frequency (rf) cavities treated by medium-temperature furnace baking (mid-T bake) was developed at the Institute of High Energy Physics, Chinese Academy of Sciences. The 9-cell cavities in the cryomodule achieved an unprecedented high average intrinsic quality factor (Q0) of 3.8×1010 at 16 MV/m and 3.6×1010 at 21 MV/m in the horizontal test. The cryomodule can operate stably up to a total continuous wave rf voltage greater than 193 MV, with an average cavity usable accelerating gradient of more than 23 MV/m. The results significantly exceed the specifications of Circular Electron Positron Collider and Dalian advanced light source and the other high repetition rate free electron laser facilities [linac Coherent light Source II (LCLS-II), LCLS-II-high energy, Shanghai High Repetition Rate X-ray FEL and Extreme light Facility, Shenzhen Superconducting Soft X-Ray Free Electron Laser, etc.]. There is evidence that the mid-T bake cavity may not require fast cooldown or long processing time in the cryomodule. This paper reviews the cryomodule performance and discusses some important issues in cryomodule assembly and testing.

关键词： Radio frequency techniques Superconducting RF

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高校健美操教学与健身俱乐部教学比较研究

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体育科技文献通报 2016年第7期24卷 72-73页

作者：李绪稳西藏民族大学体育学院陕西咸阳712082

采用文献资料研究法、实地调研法、对比分析法等,对高校健美操教学和健身俱乐部课程教学进行对比研究,认为:高校健美操课程和健身俱乐部课程在教学的目的、要求、方法、技巧上均有所不同,但两者相互影响、相互促进,能有效地提高双边教... 详细信息

采用文献资料研究法、实地调研法、对比分析法等,对高校健美操教学和健身俱乐部课程教学进行对比研究,认为:高校健美操课程和健身俱乐部课程在教学的目的、要求、方法、技巧上均有所不同,但两者相互影响、相互促进,能有效地提高双边教学质量。

关键词：健美操教学健身俱乐部相互促进

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胶体果胶铋动力黏度的测定方法

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山西化工 2020年第6期40卷 4-6,10页

作者：李娜王旭文刘艳之山西振东安特生物制药有限公司山西晋中030600

目的:建立胶体果胶铋动力黏度的测定方法,为其质量控制提供新方法。方法:将胶体果胶铋加适量水分散后,再加人工胃液形成高黏度的稳定溶胶,采用转子型旋转黏度计测定上述溶胶在37℃条件下的动力黏度。结果:3批样品动力黏度平均值分别为55... 详细信息

目的:建立胶体果胶铋动力黏度的测定方法,为其质量控制提供新方法。方法:将胶体果胶铋加适量水分散后,再加人工胃液形成高黏度的稳定溶胶,采用转子型旋转黏度计测定上述溶胶在37℃条件下的动力黏度。结果:3批样品动力黏度平均值分别为557.6、634.0、627.3 mPa·s,RSD分别为1.45%、1.43%、1.41%(n=6);样品溶液6 h内较稳定。结论:该方法简便、准确、重复性好,适合用于测定胶体果胶铋的动力黏度。

关键词：胶体果胶铋动力黏度旋转黏度计人工胃液

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国际背景下的海洋调查技术标准化发展路径研究

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海洋学研究 2020年第1期38卷 87-94页

作者：马乐天冯旭文吕小飞吴春芳李家彪自然资源部海底科学重点实验室浙江杭州310012 自然资源部第二海洋研究所浙江杭州310012

通过对比分析我国与美国、欧盟的标准战略、标准化组织机构、标准体系和海洋调查技术标准具体的制订现状,综合比较了我国与发达国家之间的差异,建议借鉴以民间自由竞争为特点的美国标准模式和以高度国际化的标准体系为特点的欧洲标准模... 详细信息

通过对比分析我国与美国、欧盟的标准战略、标准化组织机构、标准体系和海洋调查技术标准具体的制订现状,综合比较了我国与发达国家之间的差异,建议借鉴以民间自由竞争为特点的美国标准模式和以高度国际化的标准体系为特点的欧洲标准模式,同时充分发挥国际标准化组织海洋技术分委会(ISO/TC8/SC13)主席和秘书处落户中国这一平台优势的桥梁作用,探索我国海洋调查技术标准国际化的有效路径。

关键词：海洋调查技术标准国际标准化组织

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The Influence of Tool Rake Surface Geometry on the Hard Turning Process of AISI52100 Hardened Steel

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MATERIALS 2019年第19期12卷 3096-3096页

作者： Xu, Hanzhong Zhou, Honggen Ma, Zhengyu Dai, Lei Jing, xuwen li, Guochao Sun, Yujing Jiangsu Univ Sci & Technol Sch Mech Engn Zhenjiang 212000 Jiangsu Peoples R China Jiangsu Univ Sci & Technol Jiangsu Prov Key Lab Adv Mfg Marine Mech Equipmen Zhenjiang 212000 Jiangsu Peoples R China Yancheng Polytech Coll Joint Technol Transfer Ctr Yancheng 224000 Peoples R China Qilu Univ Technol Sch Mech & Automot Engn Shandong Acad Sci Jinan 250000 Shandong Peoples R China

The hard turning process has been widely used in the field of hard material precision machining because of its high efficiency, low processing residual stress, and low environmental pollution. Due to its undesirably processing quality, it is still not a substitute for traditional grinding, so many studies have reported that the process has been optimized. However, there has been little research on the geometry optimization of hard cutting tools, which have a great influence on the traditional machining process. In this paper, two tools with different rake face shapes are designed. The finite element analysis method is used to compare their performance with a conventional plane tool while turning hardened steel. The results show that the cutting performance of the designed tool T1 and T2 (chip morphology, cutting force, and cutting temperature) and the quality of the machined surface are improved compared with the tool. The cutting force decreased by 12.72% and 14.74%, the cutting temperature decreased by 7.56% and 9.01%, respectively, and the surface residual stress decreased by 26.56% and 28.66%.

关键词： hard turning coordinating chip removal finite element analysis AISI52100 hardened steel

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某电厂贮煤筒仓结构裂缝成因初探

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武汉大学学报（工学版） 2020年第S01期53卷 69-75页

作者：安旭文王勇强侯建国李兴利杨小兵武汉大学土木建筑工程学院湖北武汉430072 电力规划设计总院北京100120 中国电力顾问集团华北电力设计院有限公司北京100120

根据贮煤筒仓结构的有限元计算结果,分别按正常使用极限状态下3种荷载组合工况计算了筒仓结构仓壁下环梁底部的径向应力,以探讨仓壁下环梁底部的裂缝成因。结果表明,在各种荷载组合下,仓壁下环梁底部的径向应力小于C40混凝土的抗拉强度... 详细信息

根据贮煤筒仓结构的有限元计算结果,分别按正常使用极限状态下3种荷载组合工况计算了筒仓结构仓壁下环梁底部的径向应力,以探讨仓壁下环梁底部的裂缝成因。结果表明,在各种荷载组合下,仓壁下环梁底部的径向应力小于C40混凝土的抗拉强度标准值,说明筒仓结构在正常施工和正常使用以及保证混凝土施工质量的前提条件下,仓壁下环梁底部混凝土环向开裂的可能性较小,但仓壁下环梁底部的径向拉应力比较大,接近混凝土的抗拉强度标准值,难以完全保证仓壁下环梁底部混凝土环向不开裂。

关键词：预应力混凝土贮煤筒仓结构裂缝成因温差贮煤压力

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Improving identification ability of adulterants in powdered Panax notoginseng using particle swarm optimization and data fusion

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INFRARED PHYSICS & TECHNOLOGY 2019年 103卷 103101-000页

作者： Yang, Xiaodong Song, Jie Peng, lin Gao, Lutao liu, xuwen Xie, lin li, Guanglin Southwest Univ Coll Engn & Technol Chongqing 400715 Peoples R China Yunnan Agr Univ Coll Big Data Kunming 650201 Yunnan Peoples R China

Panax notoginseng (P. notoginseng) is frequently targeted for adulteration with lower-grade P. notoginseng because of its high price. This paper presents a novel method to improve the identification ability of adulterants using spectroscopic techniques and chemometrics. P. notoginseng powder of different grades were blended at different percentages (0-100%), in which the minimum blend ratio was 0.5%. NIR (12,497-4000 cm(-1)) and FT-MIR (4000-400 cm(-1)) spectra of samples were acquired. The wavenumbers of 7099-4200 cm(-1), 3600-2750 cm(-1), and 1750-400 cm(-1) were selected manually as characteristic spectra, which included 3706 variables. Then principal component analysis (PCA) was used to further reduce the data dimension of characteristic spectra, and the first nine principal components (PCs) were applied to build classification models of 14 (the ratio of 0.5% excluded) and 15 kinds of blend ratios. Finally, Support vector machine (SVM) was built for classification of adulterants of different blend ratio. The accuracy of prediction set is 92.46% and 91.79%, respectively. On this basis, particle swarm optimization (PSO) was applied to optimize the parameters of SVM, and the accuracy of prediction set increased to 96.65% and 96.97%, respectively. The results demonstrate that the application of data fusion of NIR and FT-MIR spectra combined with SVM optimized by PSO can improve the identification ability of adulterants in powdered P. notoginseng.

关键词： Panax notoginseng Adulteration PCA PSO SVM

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Graphene-encapsulated silica as matrix solid-phase dispersion extraction sorbents for the analysis of poly-methoxylated flavonoids in the leaves of Murraya panaculata (L.) Jack

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JOURNAL OF SEPARATION SCIENCE 2015年第12期38卷 2132-2139页

作者： Sun, Ting li, xuwen Yang, Jie li, Lanjie Jin, Yongri Shi, Xiaolei Jilin Univ Coll Chem Changchun 130062 Peoples R China Jilin Univ Coll Quartermaster Technol Changchun 130062 Peoples R China

In this study, graphene-encapsulated silica was synthesized by a hydrothermal reduction strategy. The presence of silica in graphene was identified by Fourier-transform infrared spectrometry, X-ray diffraction and scanning electron microscopy. The graphene-encapsulated silica subsequently was used as adsorbent for matrix solid-phase dispersion extraction of poly-methoxylated flavonoids from the dried leaves of Murraya panaculata (L.) Jack. Compared with the other adsorbents (graphene, silica gel, C-18 silica, neutral alumina, diatomaceous earth) and without any adsorbents, better results were obtained. Then a method for analysis of poly-methoxylated flavonoids was established by coupling matrix solid-phase dispersion extraction with ultra high performance liquid chromatography and UV detection. Compared with reflux extraction and ultrasonic extraction, the proposed method is quicker, more efficient and more environmental protection. Less than 10 min is needed from extraction to detection.

关键词： Flavonoids Graphene Matrix solid-phase dispersion Murraya panaculata Traditional Chinese medicine

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ImageSem at ImageCLEF 2018 caption task: Image retrieval and transfer learning 19

ImageSem at ImageCLEF 2018 caption task: Image retrieval and...

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19th Working Notes of CLEF Conference and Labs of the Evaluation Forum, CLEF 2018

作者： Zhang, Yu Wang, xuwen Guo, Zhen li, Jiao Institute of Medical Information Chinese Academy of Medical Sciences Peking Union Medical College Beijing100020 China

This paper presents the participation of the Image Semantics group (ImageSem) of the Institute of Medical Information at the ImageCLEF 2018 caption task. We participated in both of the concept detection and the caption prediction tasks, with submitting 15 runs in total. In this study, we applied liRE, an open source Lucene Image Retrieval, to index 222, 314 images in training and 9, 938 images in test sets. In concept detection subtask, we retrieved the similar images in the training set and applied Latent Dirichlet Allocation (LDA) for clustering concepts of the similar images. The transfer learning method was integrated to solve muti-label annotation in the concept detection task. In caption prediction, we used image retrieval strategies by tuning the parameters: the top similar images and number of candidate concepts. In the evaluation, ImageSem achieved the best Fl Score of 0.0928 in the concept detection subtask and the Mean BLEU score of 0.2501 in the caption prediction subtask.

关键词： Forecasting

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