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Magnetic properties of lithium zinc ferrites synthesized by microwave sintered method

AIP ADVANCES 2016年第5期6卷 055936-055936页

作者： Yang, Qinghui Zhang, Huaiwu Wen, Qiye liu, Yingli Yang, xuwen Univ Elect Sci & Technol China State Key Lab Elect Thin Film & Integrated Device Chengdu 610054 Sichuan Peoples R China

In this paper, a series of polycrystalline ferrite samples were prepared with the composition of Zn0.1Li0.525-xTi0.15MgxFe2.225-0.5xO4 (LiZn) (x=0, 0.05, 0.10, 0.15 and 0.20) using both microwave sintering (MS) and conventional sintering (CS) technologies, respectively. The sintering time and temperature were 22 hours and 1000 degrees C for the CS process, and 2 hours and 880 degrees C for the MS process. Experiments showed that the MS treated LiZn ferrites exhibited more excellent magnetic properties and denser, more uniform micro-structures comparing with the ones treated by CS method. For the LiZn ferrite (x=0.1) sintered at 880 degrees C using MS, the saturation magnetic induction (Bs) is 242.3 mT, the coercive force (Hc) is 135 A/m, the square ratio (Br/Bs) is 0.87 and the ferromagnetic resonance line-width (Delta H) is 143.2 Oe. These results represented very good properties for an X-band phase shifter material and indicated that the MS method is a potentially important technique for fabricating low temperature co-fired ceramics (LTCC). (C) 2016 Author(s).

关键词： Ferrites Sintering Microwaves Magnesium Optical phase shifters

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玉屏风散加减辅助治疗过敏性鼻炎的系统评价

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中国药房 2017年第21期28卷 2947-2950页

作者：郭惟何颖贤张徐文温俊茂刘煜德广州中医药大学第四临床医学院广东深圳518033 广州中医药大学第一临床医学院广州510405

目的:系统评价玉屏风散加减辅助治疗过敏性鼻炎的疗效和安全性,为临床提供循证参考。方法:计算机检索万方数据库、中文科技期刊数据库、中国期刊全文数据库、中国生物医学文献数据库、Cochrane图书馆、EMBase、Pub Med,收集玉屏风散加... 详细信息

目的:系统评价玉屏风散加减辅助治疗过敏性鼻炎的疗效和安全性,为临床提供循证参考。方法:计算机检索万方数据库、中文科技期刊数据库、中国期刊全文数据库、中国生物医学文献数据库、Cochrane图书馆、EMBase、Pub Med,收集玉屏风散加减联合化学药(试验组)对比单纯化学药(对照组)治疗过敏性鼻炎的随机对照试验,提取资料并按照Cochrane系统评价员手册5.1.0评价纳入研究质量,采用Rev Man 5.2统计软件进行Meta分析。结果:共纳入15项RCT,合计1 366例患者。Meta分析结果显示,试验组患者总有效率[OR=3.95,95%CI(2.80,5.58),P<0.001]显著高于对照组,复发率[OR=0.37,95%CI(0.22,0.63),P<0.001]和不良反应发生率[OR=0.15,95%CI(0.06,0.35),P<0.001]显著低于对照组,差异均有统计学意义。结论:玉屏风散加减辅助治疗过敏性鼻炎疗效较好,可以降低复发率,安全性亦较好。

关键词：玉屏风散过敏性鼻炎 Meta分析系统评价疗效安全性

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Experiments of Transient Condensation Heat Transfer on the Heat Flux Senor

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MICROGRAVITY SCIENCE AND TECHNOLOGY 2015年第5期27卷 369-376页

作者： Wang, xuwen liu, Qiusheng Zhu, Zhiqiang Chen, Xue Chinese Acad Sci Inst Mech Key Lab Micrograv Beijing 100190 Peoples R China

The influence of transient heat transfer in different condensation condition was investigated experimentally in the present paper. Getting condensation heat and mass transfer regularity and characteristics in space can provide theoretical basis for thermodynamic device such as heat pipes, loop heat pipes and capillary pumped loops as well as other fluid management engineering designing. In order to study the condensation process in space, an experimental study has been carried out on the ground for space experiment. The results show that transit heat transfer coefficient of film condensation is related to the condensation film width, the flow condition near the two phase interface and the pressure of the vapor and non-condensable gas in chamber. On the ground, the condensation heat flux on vertical surface is higher than it on horizontal surface. The transit heat flux of film condensation is affected by the temperature of superheated vapor, the temperature of condensation surface and non-condensable gas pressure. Condensation heat flux with vapor forced convection is many times more than it with natural convection. All of heat flux for both vapor forced convection and natural convection condensation in limited chamber declines dramatically over time. The present experiment is preliminary work for our future space experiments of the condensation and heat transfer process onboard the Chinese Spacecraft "TZ-1" to be launched in 2016.

关键词： Two-phase flow Condensation Microgravity Transient heat flux

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绿色反应介质乳酸乙酯在有机合成中的应用研究进展

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有机化学 2016年第5期36卷 954-961页

作者：韦丽陈绪文刘云云万结平江西师范大学化学化工学院南昌330022

生物质来源的乳酸乙酯作为一种新型的绿色有机反应介质逐渐受到人们的关注.这一溶剂具有无毒、生物可降解、廉价易得、沸点高、同时对水和多数有机物的优秀互溶性等各种符合理想绿色介质的优点.近几年来,以乳酸乙酯为溶剂成功实现了包括... 详细信息

生物质来源的乳酸乙酯作为一种新型的绿色有机反应介质逐渐受到人们的关注.这一溶剂具有无毒、生物可降解、廉价易得、沸点高、同时对水和多数有机物的优秀互溶性等各种符合理想绿色介质的优点.近几年来,以乳酸乙酯为溶剂成功实现了包括Suzuki偶联反应、Glaser偶联反应以及各类具有生物活性杂环化合物的串联合成等反应.本文结合我们自己的研究工作和兴趣,系统综述了近年来以乳酸乙酯为反应介质的有机合成反应研究进展.

关键词：绿色介质乳酸乙酯偶联反应缩合反应串联反应

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On the reliability of nanoindentation hardness of Al₂O₃ films grown on Si-wafer by atomic layer deposition

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JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A 2014年第1期32卷

作者： liu, xuwen Haimi, Eero Hannula, Simo-Pekka Ylivaara, Oili M. E. Puurunen, Riikka L. Aalto Univ Sch Chem Technol Dept Mat Sci & Engn FI-00076 Espoo Finland VTT Tech Res Ctr Finland FI-02044 Espoo Finland

The interest in applying thin films on Si-wafer substrate for microelectromechanical systems devices by using atomic layer deposition (ALD) has raised the demand on reliable mechanical property data of the films. This study aims to find a quick method for obtaining nanoindentation hardness of thin films on silicon with improved reliability. This is achieved by ensuring that the film hardness is determined under the condition that no plastic deformation occurs in the substrate. In the study, ALD Al2O3 films having thickness varying from 10 to 600 nm were deposited on a single-side polished silicon wafer at 300 degrees C. A sharp cube-corner indenter was used for the nanoindentation measurements. A thorough study on the Si-wafer reference revealed that at a specific contact depth of about 8 nm the wafer deformation in loading transferred from elastic to elastic-plastic state. Furthermore, the occurrence of this transition was associated with a sharp increase of the power-law exponent, m, when the unloading data were fitted to a power-law relation. Since m is only slightly material dependent and should fall between 1.2 and 1.6 for different indenter geometry having elastic contact to common materials, it is proposed that the high m values are the results from the inelastic events during unloading. This inelasticity is linked to phase transformations during pressure releasing, a unique phenomenon widely observed in single crystal silicon. Therefore, it is concluded that m could be used to monitor the mechanical state of the Si substrate when the whole coating system is loaded. A suggested indentation depth range can then be assigned to each film thickness to provide guidelines for obtaining reliable property data. The results show good consistence for films thicker than 20 nm and the nanoindentation hardness is about 11 GPa independent of film thickness. (C) 2014 American Vacuum Society.

关键词： Thin films

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Aluminum oxide from trimethylaluminum and water by atomic layer deposition: The temperature dependence of residual stress, elastic modulus, hardness and adhesion

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THIN SOLID FILMS 2014年第0期552卷 124-135页

作者： Ylivaara, Oili M. E. liu, xuwen Kilpi, Lauri Lyytinen, Jussi Schneider, Dieter Laitinen, Mikko Julin, Jaakko Ali, Saima Sintonen, Sakari Berdova, Maria Haimi, Eero Sajavaara, Timo Ronkainen, Helena Lipsanen, Harri Koskinen, Jari Hannula, Simo-Pekka Puurunen, Riikka L. VTT Tech Res Ctr Finland FI-02044 Espoo Finland Aalto Univ Sch Chem Technol Dept Mat Sci & Engn FI-00076 Aalto Finland Fraunhofer IWS Dresden D-01277 Dresden Germany Univ Jyvaskyla Dept Phys FI-40014 Jyvaskyla Finland Aalto Univ Sch Elect Engn Dept Micro & Nanosci FI-00076 Aalto Finland Aalto Univ Sch Chem Technol Dept Mat Sci & Engn FI-00076 Aalto Finland Aalto Univ Sch Chem Technol Micronova Nanofabricat Ctr FI-00076 Aalto Finland

Use of atomic layer deposition (ALD) in microelectromechanical systems (MEMS) has increased as ALD enables conformal growth on 3-dimensional structures at relatively low temperatures. For MEMS device design and fabrication, the understanding of stress and mechanical properties such as elastic modulus, hardness and adhesion of thin film is crucial. In this work a comprehensive characterization of the stress, elasticmodulus, hardness and adhesion of ALD aluminum oxide (Al2O3) films grown at 110-300 degrees C from trimethylaluminum and water is presented. Film stress was analyzed by wafer curvature measurements, elastic modulus by nanoindentation and surface-acoustic wave measurements, hardness by nanoindentation and adhesion by microscratch test and scanning nanowear. The films were also analyzed by ellipsometry, optical reflectometry, X-ray reflectivity and time-of-flight elastic recoil detection for refractive index, thickness, density and impurities. The ALD Al2O3 films were under tensile stress in the scale of hundreds of MPa. The magnitude of the stress decreased strongly with increasing ALD temperature. The stress was stable during storage in air. Elastic modulus and hardness of ALD Al2O3 saturated to a fairly constant value for growth at 150 to 300 degrees C, while ALD at 110 degrees C gave softer films with lower modulus. ALD Al2O3 films adhered strongly on cleaned silicon with SiOx termination. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Atomic layer deposition Residual stress Elastic modulus Hardness Adhesion Aluminum oxide

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SLP Approach Based Facility Layout Optimization:An Empirical Study

SLP Approach Based Facility Layout Optimization:An Empirical...

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2016管理与组织国际会议

作者： Weiying Chen Changyu liu xuwen Huang Hualiang Lai Binfeng Li College of Mathematics and Informatics South China Agricultural University Konka Group Limited by Share Ltd

Favorable facility layouts could effectively improve production efficiency, reduce production cost, and improve comprehensive competitiveness. Take the inefficient workshop facility layout of the H Company as an example, the paper studies both transportation and processing cycle for raw materials of its main products, records statistically transport distances and transport weights for each raw material in each processing workshop, and discovers principal issues in the transportation and processing cycle for the H Company. This paper adopts the Systematic Layout Planning(SLP) approach to optimize the layout design of the H Company, and compares non-optimized layout scheme with optimized one from qualitative and quantitative analysis aspect by using the analytic hierarchy process approach. The results show that the application of SLP approach in the H Company could enhance obviously the performance of its workshop facility layout.

关键词： Systematic Layout Planning(SLP) Facility Layout Optimization Empirical Study Analytic Hierarchy Process

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Thermal and plasma enhanced atomic layer deposition of SiO₂ using commercial silicon precursors

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THIN SOLID FILMS 2014年 558卷 93-98页

作者： Putkonen, Matti Bosund, Markus Ylivaara, Oili M. E. Puurunen, Riikka L. Kilpi, Lauri Ronkainen, Helena Sintonen, Sakari Ali, Saima Lipsanen, Harri liu, xuwen Haimi, Eero Hannula, Simo-Pekka Sajavaara, Timo Buchanan, Iain Karwacki, Eugene Vaha-Nissi, Mika VTT Tech Res Ctr Finland FI-02044 Espoo Finland Aalto Univ Sch Chem Technol Inorgan Chem Lab FI-00076 Espoo Finland Beneq Oy FI-01510 Vantaa Finland Aalto Univ Sch Elect Engn Dept Micro & Nanosci FI-00076 Espoo Finland Aalto Univ Sch Chem Technol Dept Mat Sci & Engn FI-00076 Espoo Finland Univ Jyvaskyla Dept Phys FI-40014 Jyvaskyla Finland Air Prod & Chem Inc Allentown PA 18195 USA

In this paper, we report ALD deposition of silicon dioxide using either thermal or plasma enhanced atomic layer deposition (PEALD). Several aminosilanes with differing structures and reactivity were used as silicon precursors in R&D single wafer ALD tools. One of the precursors was also tested on pilot scale batch ALD using O-3 as oxidant and with substrates measuring 150 x 400 mm. The SiO2 film deposition rate was greatly dependent on the precursors used, highest values being 1.5-2.0 angstrom/cycle at 30-200 degrees C for one precursor with an O-2 plasma. According to time-of-flight-elastic recoil detection analysis measurements carbon and nitrogen impurities were relatively low, but hydrogen content increased at low deposition temperatures. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Atomic layer deposition Plasma-enhanced atomic layer deposition Precursors Silicon dioxide Batch deposition Conformal coating

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Misdiagnosis of a Patient with Internal Carotid Artery Fenestration: A Case Report and Literature Review

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ANNALS OF VASCULAR SURGERY 2016年 30卷 309.e1-309.e4页

作者： Liang, Zhigang Xiu, Chunming liu, Zhuli Sun, xuwen Yu, Guoping Tao, Manli Li, Wei Qingdao Univ Coll Med Affiliated Yantai Yuhuangding Hosp Dept Neurol Yantai Shandong Peoples R China Capital Med Univ Beijing Tiantan Hosp Dept Neurol Beijing Peoples R China

Background: Internal carotid artery fenestration is a rare congenital cerebrovascular condition and can be misdiagnosed as carotid artery dissection. Case Report: A patient was initially misdiagnosed with carotid artery dissection. This initial diagnosis was made using a carotid vascular computed angiography and magnetic resonance angiography. A digital subtraction angiography examination revealed a fenestration in the terminal C1 segment of the right internal carotid artery. Previous literature related to carotid artery fenestration was reviewed and analyzed. Conclusions: Fenestration of the carotid artery combined with aneurysm at the external segment of the internal carotid artery or from the starting position of the carotid artery remains rare in elderly patients, can be misdiagnosed as artery dissection.

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离子交换树脂吸附黄连素废水中铜离子的研究

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环境工程技术学报 2017年第2期7卷 181-187页

作者：崔晓宇何绪文单永平曾萍刘瑞霞孙晨中国矿业大学(北京)化学与环境工程学院北京100083 环境基准与风险评估国家重点实验室中国环境科学研究院北京100012 中国环境科学研究院城市水环境科技创新基地北京100012 德国亥姆霍兹环境研究中心环境微生物学院莱比锡04318

以Cu^(2+)-黄连素混合体系的含铜制药废水为研究对象,考察3种离子交换树脂(D152、D113和D401)对含铜废水中Cu^(2+)和黄连素的吸附性能并对树脂进行了筛选,对D401树脂进行了吸附动力学和吸附热力学拟合分析,同时考察该树脂在黄连素竞争... 详细信息

以Cu^(2+)-黄连素混合体系的含铜制药废水为研究对象,考察3种离子交换树脂(D152、D113和D401)对含铜废水中Cu^(2+)和黄连素的吸附性能并对树脂进行了筛选,对D401树脂进行了吸附动力学和吸附热力学拟合分析,同时考察该树脂在黄连素竞争吸附影响下对Cu^(2+)的去除效果。最后,在静态试验基础上开展了动态试验,考察D401树脂柱在3种流速[1、2和5 BV(柱体积)/h]下,进样量为1~20 BV时出水的Cu^(2+)和黄连素浓度。结果表明:D401树脂的比吸附量随温度升高而增加,随树脂投加量的增加而降低;该树脂在较宽的pH范围内对Cu^(2+)具有很好的选择吸附性,pH为5.0是最佳吸附条件,此时比吸附量可达39.87 mg/g。吸附过程可以通过Langmuir吸附等温线和伪二级动力学模型进行描述。动态试验中,树脂柱在1 BV/h的流速下,对Cu^(2+)有较好的去除效果;在3种流速条件下,对黄连素的吸附率均较低,进一步验证了该型树脂对Cu^(2+)具有很好的选择吸附性。

关键词：树脂铜离子吸附热力学动力学黄连素废水

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