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NaYF4∶Yb^3+,Ln^3+@NaYF4∶Yb^3+@NaYF4(Ln=Ho,Tm)核-双层壳纳米晶中Yb^3+调控的高效上转换发光

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发光学报 2020年第9期41卷 1102-1113页

作者：廖华珍肖萍叶松王德平同济大学材料科学与工程学院上海201804

采用共沉淀法合成了尺寸小于10 nm的Yb^3+/Ln^3+(Ln=Ho^3+,Tm^3+)掺杂β-NaYF4核纳米晶,在此基础上构建了NaYF4∶Yb^3+,Ln^3+@NaYF4∶Yb^3+@NaYF4核-双层壳结构纳米晶,并通过XRD和TEM测试证明了中间活性壳和最外层惰性壳的成功包覆。光... 详细信息

采用共沉淀法合成了尺寸小于10 nm的Yb^3+/Ln^3+(Ln=Ho^3+,Tm^3+)掺杂β-NaYF4核纳米晶,在此基础上构建了NaYF4∶Yb^3+,Ln^3+@NaYF4∶Yb^3+@NaYF4核-双层壳结构纳米晶,并通过XRD和TEM测试证明了中间活性壳和最外层惰性壳的成功包覆。光谱结果表明,在活性核和活性壳中分别掺杂Yb^3+、并进一步生长最外层的惰性壳能够有效地提高Ho^3+和Tm^3+的上转换发射强度,这是由核-双层壳结构纳米晶对980 nm激发光的吸收增强以及Yb^3+浓度猝灭阈值的提高所引起的高效能量传递共同导致的。此外,通过调节中间壳层中的Yb^3+掺杂浓度,可以获得高效可调发光。本研究为开发多色高效上转换发光纳米晶提供了一条有效的途径。

关键词：上转换发光核-双层壳结构 β-NaYF4

Modelling of grain boundary impurity segregation during high temperature plastic deformation

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Science China(Physics,Mechanics & Astronomy) 2011年第5期54卷 872-877页

作者： CHEN XianMiao song ShenHua Department of Materials Science and Engineering Shenzhen Graduate School Harbin Institute of Technology Shenzhen 518055 China

A modified theoretical model is proposed to predict the grain boundary segregation of impurity atoms during high temperature plastic deformation. The model is based on the supersaturated vacancy-impurity complex created by plastic deformation and involves quasi-thermodynamics and kinetics. Model predictions are made for phosphorus grain boundary segregation during plastic deformation in ferrite steel. The results reveal that phosphorus segregates at grain boundaries during plastic deformation. At a given temperature, under a certain strain rate the segregation increases with increasing deformation amount until reaching a steady value, and at the same deformation amount it increases with increasing strain rate. The predicted results are compared with the available experimental values, indicating that there is a reasonable agreement between the theoretical predictions and the experimental observations.

关键词： grain boundary non-equilibrinm segregation plastic deformation

Application of blunt dissection in ESD of a gastric submucosal tumor

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World Journal of Gastroenterology 2014年第21期20卷 6698-6700页

作者： Zong-Quan Wen Guang-Yao Wu Shao-ping Yu Xiao-Dong Lin song-Hu Li Xian-Guang Huang Fu Zhang Xiao-Yu Zeng Hai-Yan Huang Ai-Mei Li Department of Gastroenterology Dongguan Kanghua Hospital Department of Endoscopy Centre Dongguan Kanghua Hospital

We performed endoscopic submucosal dissection of a gastric fundus *** was difficult to strip the tumor completely due to space limitation,and we used blunt dissection to remove the tumor quickly and ***,the basal area of the 2.5 cm submucosal tumor located in the gastric fundus was cut open,and the mucosa was *** tumor was difficult to peel,therefore,a snare was used and the tumor was pulled and tightened *** electronic coagulation was used during the *** tumor was then bluntly *** method ensured rapid and complete removal of the tumor.

关键词： Blunt dissection Endoscopic submucosal dissection Gastric fundus submucosal tumor

Regionally proximal relation of order d along arithmetic progressions and nilsystems

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Science China Mathematics 2020年第9期63卷 1757-1776页

作者： Eli Glasner Wen Huang song Shao Xiangdong Ye School of Mathematics Tel Aviv UniversityTel Aviv 6997801Israel CAS Wu Wen-Tsun Key Laboratory of Mathematics and School of Mathematics University of Science and Technology of ChinaHefei 230026China

The regionally proximal relation of order d along arithmetic progressions,namely AP[d]for d 2 N,is introduced and *** turns out that if(X;T)is a topological dynamical system with AP[d]=Δ,then each ergodic measure of(X;T)is isomorphic to a d-step pro-nilsystem,and thus(X;T)has zero ***,it is shown that if(X;T)is a strictly ergodic distal system with the property that the maximal topological and measurable d-step pro-nilsystems are isomorphic,then AP[d]=RP[d]for each d 2 *** follows that for a minimal 1-pro-nilsystem,AP[d]=RP[d]for each d 2 *** example which is a strictly ergodic distal system with discrete spectrum whose maximal equicontinuous factor is not isomorphic to the Kronecker factor is constructed.

关键词： regionally proximal relation pro-nilsystem discrete spectrum equicontinuous factor

A report on pneumonia-induced ventriculitis with intraventricular abscess

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Chinese Medical Journal 2021年第2期134卷 247-248页

作者： yong-Gang Gui Yan-Fen Chai song-Tao Shou Chen-Guang Zhao Department of Emergency Medicine Tianjin Medical University General HospitalTianjin 300052China

To the Editor:Ventriculitis,also known as ependymitis,ventricular empyema,pyocephalus,or pyogenic ventriculitis,is the inflammation of the ependymal lining of the cerebral *** inflammation of the ventricular drainage system is usually secondary to bacterial infection of the cerebrospinal *** morbidity associated with ventriculitis has been reported in up to 45%of patients.[1]Generally,neurosurgical patients or patients with head trauma are particularly at risk of developing ventriculitis,when these patients are treated with cerebrospinal fluid shunts or drains,implantation of intrathecal infusion pumps,or implantation of deep brain stimulation hardware.[2]Clinically,most patients with ventriculitis present with fever,deterioration of the conscious level,and dysneuria.[3]Delayed in the diagnosis and treatment will lead to severe intracranial infection,serious neurological impairment,and *** cases of ventriculitis have been reported in the newborns and infants,with bacteria being the most common pathogens,although several cases of ventriculitis secondary to aspergillus fumigatus infection have been described.

关键词： ventricular inflammation stimulation

Geometry Design and Tooth Contact Analysis of Crossed Beveloid Gears for Marine Transmissions

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Chinese Journal of Mechanical Engineering 2012年第2期25卷 328-337页

作者： ZHU Caichao song Chaosheng LIM Teik Chin VIJAYAKAR Sandeep State Key Laboratory of Mechanical Transmission Chongqing UniversityChongqing 400030China School of Dynamics Systems at University of Cincinnati CincinnatiOhio 45221USA Advanced Numerical Solutions 3956 Brown Park DriveSuite BHilliardOhio 43026USA

Beveloid gears,also known as conical gears,gain more and more importance in industry practice due to their abilities for power transmission between parallel,intersected and crossed ***,this type of gearing with crossed axes has no common plane of action which results in a point contact and low tooth ***,a geometry design approach assuming line contact is developed to analyze the tooth engagement process of crossed beveloid gears with small shaft angle for marine transmission *** loaded gear tooth contact behavior is simulated by applying a quasi-static analysis to study the effects of gearing parameters on mesh *** the proposed method,a series of sensitivity analyses to examine the effects of critical gearing parameters such as shaft angle,cone angle,helix angle and profile-shift coefficient on the theoretical gear mesh is *** parametric analysis of pitch cone design shows that the dominant design parameters represented by the angle between the first principle directions（FPD） and normal angular factor are more sensitive to the shaft and cone angles than they are to the helix *** theoretical contact path is highly sensitive to the profile-shift coefficient,which is determined from the theoretical tooth contact *** FPD angle is found to change the distribution of contact pattern,contact pressure and root stress as well as the translational transmission error and the variation of the mesh stiffness *** contact pattern is clearly different between the drive and coast sides due to different designed FPD ***,a practical experimental setup for marine transmission is performed and tooth bearing test is conducted to demonstrate the proposed design *** experimental result compared well with the *** of this study yield a better understanding of the geometry design and loaded gear mesh characteristics for crossed beveloid gears used in marine trans

关键词： beveloid gears loaded tooth contact analysis crossed axes marine transmission

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翘曲端壁对大折转角压气机叶栅流动的影响

航空动力学报 2015年第5期30卷 1236-1243页

作者：崔可宋彦萍刘华坪陈浮哈尔滨工业大学能源科学与工程学院哈尔滨150001

研究了翘曲端壁对大折转角压气机叶栅流动的影响.结果表明:翘曲最高点位于压力面时效果较好,翘曲高度为2%叶高时出口总压损失下降约5.8%;而翘曲最高点位于压力面与吸力面之间时效果则不理想;翘曲高度为5%叶高、翘曲最高点距压力面为0.2... 详细信息

研究了翘曲端壁对大折转角压气机叶栅流动的影响.结果表明:翘曲最高点位于压力面时效果较好,翘曲高度为2%叶高时出口总压损失下降约5.8%;而翘曲最高点位于压力面与吸力面之间时效果则不理想;翘曲高度为5%叶高、翘曲最高点距压力面为0.25倍节距时出口总压损失增加约3.4%,此时端壁附近压力梯度呈先顺后逆变化,低能流体由压力面端区迁移至10%叶高处与吸力面附近低能流体汇合,增加了流道内二次流强度;当来流攻角不为零时,下端壁翘曲所构造的反向压差对于减小二次流强度、降低出口总压损失的效果仍比较明显,+3°攻角下出口总压损失减小约5.6%,-3°攻角下出口总压损失减小约3.5%,但同时其导致的负荷沿径向重新分配也将使得上端壁附近流动状况也发生改变.

关键词：翘曲端壁造型大折转角压气机二次流

WCDMA系统中Internet访问性能的优化

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北京邮电大学学报 2005年第2期28卷 4-8页

作者：王钺宋永华任勇山秀明清华大学电子工程系北京100084 英国布鲁内尔大学电子与计算机工程系

为提高在WCDMA系统中进行无线Internet访问的性能,研究了一种基于代理的新机制,并运用排队论建立起解析模型以分析其性能.新机制充分利用了数据业务对延时不敏感的特性,可以在不降低利用率的前提下缩短系统的平均响应时间.同时,分析结... 详细信息

为提高在WCDMA系统中进行无线Internet访问的性能,研究了一种基于代理的新机制,并运用排队论建立起解析模型以分析其性能.新机制充分利用了数据业务对延时不敏感的特性,可以在不降低利用率的前提下缩短系统的平均响应时间.同时,分析结果表明,在上述系统中影响平均响应时间的关键参数是并行的传输信道数.为此,进一步讨论了并行信道数的选择与系统性能的优化问题,并针对网络的时变特性给出了一种自适应信道调整的算法.仿真试验表明自适应算法可以在各种业务条件下有效地缩短系统的平均响应时间.

关键词： WCDMA 无线Internet访问代理

电流源型逆变器SHE-PWM开关角度的计算方法研究

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中国电机工程学报 2005年第17期25卷 62-65页

作者：官二勇宋平岗叶满园刘顺炮华东交通大学电气工程学院江西省南昌市330013 东南大学电气工程系江苏省南京市210096

该文以电流源型逆变器(CSI)为研究对象,对特定消谐技术(SHE)的应用进行了分析和研究;针对用数值方法求解SHE-PWM开关角度时,非线性超越方程组计算初值选择困难的问题,提出了以梯形调制法(TPWM)生成方程组初值的方法,使求解速度明显加快... 详细信息

该文以电流源型逆变器(CSI)为研究对象,对特定消谐技术(SHE)的应用进行了分析和研究;针对用数值方法求解SHE-PWM开关角度时,非线性超越方程组计算初值选择困难的问题,提出了以梯形调制法(TPWM)生成方程组初值的方法,使求解速度明显加快;根据非线性方程组的数值解进行了仿真和实验,其结果证明了计算结果的正确性。

关键词：电力电子特定消谐技术非线性超越方程组电流源型逆变器