检索结果-南通市图书馆

Luminescence properties of near-UV excitable yellow-orange light emitting warm CaSrAl_2SiO_7:Sm^(3+) phosphors

Journal of Rare Earths 2019年第4期37卷 365-373页

作者： Shweta Sharma nameeta brahme D.P.Bisen Pradeep Dewangan School of Studies in Physics and Astrophysics Pt.Ravishankar Shukla University Center for Nanoscience and Nanotechnology Pt.Ravishankar Shukla University

Single-phase CaSrAl_2 SiO_7:Sm^(3+) phosphors were synthesized by traditional high temperature solid state reaction method. Formation of samples and phase analysis were confirmed by X-ray diffraction technique. Morphology was done by field emission scanning electron microscopy and elemental compositions were confirmed by energy dispersive X-ray analysis. Present phosphors have tetragonal crystallography with space group P42_1 m. Average crystallite size was calculated by using Scherrer and Williamson-Hall method. Photoluminescence study of CaSrAl_2 SiO_7:Sm^(3+) phosphor was *** different excitation wavelengths, PL spectra consist of four emission bands at 564, 570, 601 and650 nm. The emission bands located at 564 and 570 nm are associated with the transition ~4 G_(5/2)→~6 H_(5/2)while emission bands at 601 and 650 nm are due to ~4 G_(5/2)→~6 H_(7/2) and ~4 G_(5/2)→~6 H_(9/2),*** emission was obtained when phosphor was excited under 404 nm wavelength. Non-radiative energy transfer process involved in concentration quenching, was also discussed. CIE coordinate is found in yellow-orange region, hence CaSrAl_2SiO_7:Sm^(3+) phosphors emit yellow-orange light when efficiently excited by near UV(～400 nm) LED chip. Color purity and CCT of the phosphor were determined; CCT suggests that present phosphor is a good candidate as a warm yellow-orange color emitting phosphor. Effect of different heating rates and different UV exposure time on the TL glow curve of the phosphor was investigated. Activation energies and kinetic parameters for different traps were calculated by using peak shape method. TL emission spectrum was also recorded. Present article explains all the possible mechanisms associated with luminescence process in CaSrAl_2 SiO_7:Sm^(3+) phosphors.

关键词： Thermoluminescence Photoluminescence Aluminosilicate Yellow-orange emitting phosphor Samarium CaSrAl2SiO7:Sm3+

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Comparative Analysis of Microleakage of Roots Filled with Different Obturation Techniques and Materials-an in Vitro Study

A Comparative Analysis of Microleakage of Roots Filled with ...

引用

作者： nameeta Shrestha 重庆医科大学

学位级别：硕士

Background:Endodontic therapy, over a period of time, has developed into an art and science to retain grossly carious, infected and mutilated teeth whenever possible, hence valuing each tooth more than a diamond;and increasing its longevity in the mouth to the greatest possible extent. The primary objective of a root canal therapy is to remove the organic and inorganic substances and also microorganisms to achieve a perfect seal at the apical region. The necessity to provide a perfect seal at the apical region as well as filling of accessory canals have brought forth many dynamic changes in obturation techniques and materials used as sealers.Gutta-percha has been used for root canal filling for more than a century. Many techniques have been introduced over the years for efficient and effective filling of the root canal space with gutta-percha. The E & Q Plus system (Meta Biomed Co., Ltd., UK) is a relatively new introduction to the endodontic armamentarium for root canal filling. The system consists of a control unit with a pen-grip device holding a heating tip, as well as a gutta-percha injection gun. Recently, a new cold flowable filling system - GuttaFlow (Coltene Whaledent, Germany), has been introduced for the obturation of root canals, combining sealer and gutta-percha in one product. It consists of a polydimethylsiloxane matrix highly filled with very finely ground gutta-percha, that are homogeneously mixed in a mixing capsule. GuttaFlow is said to have extraordinary chemical and physical properties that offer maximum sealing quality and biocompatibility. It easily flows into lateral canals and dentinal tubules;and it does not shrink upon setting, rather it expands by 0.2%.During the obturation procedure, the gutta-percha cone does not bind by itself to the canal wall, so a root canal sealer is necessary to bind the gutta-percha to the canal walls;and hence adhesiveness of a root canal sealer is a desirable property. Generally root canal sea

关键词： Root canal obturation microleakage

来源：

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

pEGFP-N_1-BMP_2真核表达载体的构建及其经超声微泡介导转染HPDLFs后的表达

引用

重庆医学 2010年第9期39卷 1045-1047,1050,F0003页

作者：仲琳钟晓波张云燕骆书美 nameeta Shrestha 齐进李春光重庆医科大学附属口腔医院牙体牙髓科 400016

目的构建pEGFP-N1-BMP2真核表达质粒,并检测其经超声微泡转基因技术转染人牙周膜成纤维细胞(HPDLFs)后的瞬时表达情况。方法从人胎盘滋养层细胞系中提取总RNA,采用RT-PCR方法获得目的基因人骨形成蛋白-2(hBMP2)基因片段,连接pMD19-T载... 详细信息

目的构建pEGFP-N1-BMP2真核表达质粒,并检测其经超声微泡转基因技术转染人牙周膜成纤维细胞(HPDLFs)后的瞬时表达情况。方法从人胎盘滋养层细胞系中提取总RNA,采用RT-PCR方法获得目的基因人骨形成蛋白-2(hBMP2)基因片段,连接pMD19-T载体并测序正确后与真核荧光表达载体pEGFP-N1连接,酶切鉴定后利用超声微泡转基因技术转染入HPDLFs中,通过荧光显微镜和RT-PCR检测目的基因在HPDLFs中的表达。结果成功克隆人BMP2基因,重组质粒pEGFP-N1-BMP2经PCR及双酶切鉴定均证实hBMP2基因已与pEGFP-N1正确重组。pEGFP-N1-BMP2经超声微泡转染HPDLFs后,通过绿色荧光观察和RT-PCR检测证实hBMP2能够在体外培养的HPDLFs内有效的转录和瞬时表达。结论成功构建pEG-FP-N1-BMP2真核表达载体,通过超声微泡转基因技术成功转染入HPDLFs并得到有效表达,为进一步研究该质粒与超声微泡转基因技术在牙周再生基因治疗中的应用提供实验基础。

关键词：牙周再生超声微泡人骨形成蛋白-2 增强型绿色荧光蛋白基因转染人牙周膜成纤维细胞

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：