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Spectral properties of Tm,Ho:LiYF_4 laser crystal

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Journal of Rare Earths 2011年第6期29卷 592-595页

作者：李春张莹张学建曾繁明 mauro.tonelli 刘景和 School of Materials Science and Engineering Changchun University of Science and Technology Office of Foreign Affairs Jilin Architectural and Civil Engineering Institute NEST-CNR and Dipartimento di Fisica Universita` di Pisa Largo B. Pontecorvo 3 56127 Pisa Italy

The LiYF4 single crystal codoped with thulium and holmium ions was successfully grown by the Cz method. The optimal technical parameters obtained were as follows： the pulling rate was 0.16 mm/h; the rotation speed was 3 rpm; the cooling rate was 15 °C/h. The result of XRD curve showed that as-grown Tm,Ho：LiYF4 laser crystal belonged to the monoclinic system with scheelite-type structure and space group I41/a. The cell parameters calculated were： a=0.52160 nm, c=1.09841 nm and Z=4. Absorption and fluorescence spectra of Tm,Ho：LiYF4 laser crystal at room temperature were measured and analysed. The absorption cross section, FWHM and absorption coefficient at 779.3 nm calculated were 7.44×10–21 cm2, 8.7 nm and 2.23 cm–1, respectively. An intensive fluorescence emission peak appeared near 2045 nm. The emission cross section and fluorescence lifetime were 0.87×10–20 cm2 and 10.8 ms, respectively. The ratio of Tm–Ho transfer to its back-transfer process was 10.6.

关键词： Tm Ho:LiYF4 laser crystal Cz method absorption spectrum fluorescence spectrum rare earths

Growth and spectral properties of Nd3+-doped potassium ytterbium tungstate laser crystal

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Growth and spectral properties of Nd3+-doped potassium ytter...

Temperature-Dependent Fluorescence Properties and Diode-Pumped Deep Red Laser Performance of Pr:LiGdF4 Crystal

第六届国际稀土开发与应用研讨会

作者： mauro.tonelli Department of physics The University of Pisa

The 5at.%Nd -doped potassium ytterbium tungstate(KNdYb(WO)) laser crystal with the dimension up to 28mm×l5mm×12mm was grown by the Kyropoulos method for the first *** unpolarization absorption spectrum of the crystal sample with the dimension of 3×3×1mm cut perpendicularly to the b axis was *** absorption cross sections is 16.03×l0cm at 808nm with an FWHM of *** strongest absorption peak observed at 890—1000nm is due to the I-F transition in Nd overlapping with the F—F transition in *** is indicated that effective energy transfer between Nd and Yb ions can be *** on the Judd-Ofelt theory,the intensity parametersΩ(λ=2,4,6) calculated were:Ω=9.39×l0cm,Ω=3.18×l0cm,Ω=3.35×*** fluorescence spectrum was measured in the 950-1150 nm range at room *** fluorescence life of F energy level is 196.33us,and the fluorescence branching ratio for the F—I transition at 1067nm is 55.74%.The energy transfer between Nd and Yb ions was observed from the fluorescence spectra pumped by 808nm and 980nm LD sources,and the Stark levels of Yb in Nd:KYbW crystal were determined.

关键词： Nd3+ -doped potassium ytterbium tungstate Kyropoulos method laser crystal growth spectral properties rare earths

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Chinese Physics Letters 2015年第5期32卷 86-90页

作者：张玉霞王树贤 Alberto Di Lieto 于果蕾于浩海张怀金 mauro.tonelli 徐现刚王继扬 State Key Laboratory of Crystal Materials and Institute of Crystal Materials Shandong University Jinan 250100 NEST Istituto Nanoscienze-CNR and Dipartimento di Fisica dell'UniversitA di Pisa Largo B. Pontecorvo 3 Pisa 56127 Italy 3 Inspur Hizaguang Optoelectronics Co. Ltd Jinan 250101

We demonstrate the temperature-dependent fluorescence properties of Pr：LiGdF4 crystal tor the first time, to the best of our knowledge, and its blue diode pumped cw red laser at 720 nm at room temperature. The fluorescence lifetime and polarized emission cross sections in the visible range are measured and calculated in a temperature range from 77K to 300 K, and the variations of the fluorescence lifetime and spectra are discovered. The reasons for these changes are explained accordingly. The output wavelength of the 720nm laser is first reported on the laser performance by using a fiber-coupled laser diode at the wavelength of 442nm as the pump source, and the maximum cw output power is about 303roW.

关键词： Pr Temperature-Dependent Fluorescence Properties and Diode-Pumped Deep Red Laser Performance of Pr:LiGdF4 Crystal

高浓度铒离子掺杂钨酸镱钾激光晶体上转换发光研究(英文)

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红外与激光工程 2012年第9期41卷 2322-2327页

作者：张莹刘景和李春林海曾繁明 mauro.tonelli 中国科学院长春光学精密机械与物理研究所吉林长春130033 长春理工大学材料科学与工程学院吉林长春130022 意大利比萨大学比萨56127

首次采用泡生法生长了掺铒钨酸镱钾(分子式:Er3+:KYb(WO4)2,简称:Er:KYbW)激光晶体。室温下测试了该晶体的吸收及上转换发射光谱。在荧光光谱中,观察到3个较为明显的上转换发射带,分别位于470~560nm,645~675 nm,750~850 nm。其中,位于53... 详细信息

首次采用泡生法生长了掺铒钨酸镱钾(分子式:Er3+:KYb(WO4)2,简称:Er:KYbW)激光晶体。室温下测试了该晶体的吸收及上转换发射光谱。在荧光光谱中,观察到3个较为明显的上转换发射带,分别位于470~560nm,645~675 nm,750~850 nm。其中,位于533 nm处的上转换绿光强度最大。基于能量匹配原理分析了晶体上转换发光基质,结果表明,上转换红光和绿光的发光渠道均为双光子过程。根据J-O理论,计算了光谱参数,强度参数为:Ω2=16.342×10-20cm2,Ω4=4.183×10-20cm2,Ω6=1.264×10-20cm2;对应于绿光4S3/2-4I15/2跃迁的荧光分支比为76.37%,荧光寿命为278μs。这些光学参数表明Er:KYbW激光晶体可实现高效上转换绿光发射。

关键词：掺铒钨酸镱钾激光晶体上转换发光光谱参数

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掺钕钨酸钆钠晶体生长、结构及光谱特性

硅酸盐学报 2010年第2期38卷 177-182页

作者：林海张莹李春曾繁明秦杰明 mauro.tonelli 刘景和长春理工大学材料科学与工程学院长春130022 意大利比萨大学物理系意大利比萨56127

采用提拉法生长了尺寸为φ(30～35)mm×80mm的掺钕钨酸钆钠[Nd:NaGd(WO4)2,Nd:NGW]晶体。生长Nd:NGW晶体的最佳工艺参数为:晶体的提拉速率为1～2mm/h,晶体转速为15～18r/min,冷却速率为10℃/h,液面上轴向温度梯度为0.7～1℃/mm。通过热... 详细信息

采用提拉法生长了尺寸为φ(30～35)mm×80mm的掺钕钨酸钆钠[Nd:NaGd(WO4)2,Nd:NGW]晶体。生长Nd:NGW晶体的最佳工艺参数为:晶体的提拉速率为1～2mm/h,晶体转速为15～18r/min,冷却速率为10℃/h,液面上轴向温度梯度为0.7～1℃/mm。通过热重-差热分析(thermogravimetry-differential thermal analysis,TG-DTA),X射线衍射(X-ray diffraction,XRD)对晶体进行表征。测试了晶体的红外及Raman光谱,分析了晶体的振动模式,并将晶体振动光谱进行归属。由TG-DTA曲线得到晶体熔点为1251.7℃。XRD分析表明:晶体属于四方晶系、白钨矿结构、I41/a空间群,晶胞参数a=0.53213nm,c=1.13070nm。吸收光谱表明:Nd:NGW晶体在805nm附近有较强、较宽的吸收峰,吸收截面积为3.581×10-20cm2,适合于激光二极管泵浦。

关键词：掺钕钨酸钆钠晶体提拉法红外光谱 Raman光谱吸收光谱

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Yb:NGW激光晶体生长及光谱性能

硅酸盐学报 2010年第5期38卷 825-830页

作者：林海张莹李春张学建曾繁明 mauro.tonelli 刘景和长春理工大学材料科学与工程学院长春130022 吉林建筑工程学院材料科学与工程学院长春130021 意大利比萨大学物理系意大利比萨56127

采用提拉法生长了φ30mm×70mm的掺镱钨酸钆钠[Yb:NaGd(WO4)2,Yb:NGW]晶体,并对晶体进行了退火处理。讨论了Yb:NGW晶体的生长工艺。确定了最佳生长工艺参数为:提拉速率为1～2mm/h,转速为15～18r/min,冷却速率为10℃/h,轴向温度梯度为液... 详细信息

采用提拉法生长了φ30mm×70mm的掺镱钨酸钆钠[Yb:NaGd(WO4)2,Yb:NGW]晶体,并对晶体进行了退火处理。讨论了Yb:NGW晶体的生长工艺。确定了最佳生长工艺参数为:提拉速率为1～2mm/h,转速为15～18r/min,冷却速率为10℃/h,轴向温度梯度为液面上0.7～1℃/mm。通过热重–差热分析(thermogravimetry–differential thermal analysis,TG–DTA),X射线衍射(X-raydiffraction,XRD)对退火的晶体进行表征。测试了晶体的红外光谱和Raman光谱,并对出现的峰值进行了振动归属。测量了晶体的吸收光谱和荧光光谱。由TG–DTA曲线得到晶体熔点为1252.02℃。XRD分析表明:晶体属于四方晶系、白钨矿结构、I41/a空间群,计算的晶胞参数a=0.53603nm,c=1.11628nm。吸收光谱显示:晶体在968nm处吸收峰最强,半峰宽为57nm,适合激光二极管泵浦。

关键词：掺镱钨酸钆钠晶体提拉法激光晶体 Raman光谱吸收光谱荧光光谱

ABCDE—agile block chain DApp engineering

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Blockchain(Research and Applications) 2020年第1期1卷 18-35页

作者： Lodovica Marchesi Michele Marchesi Roberto tonelli DMI University of CagliariCagliari09124Italy

Blockchain software development is becoming more and more important for any modern software developer and IT ***,blockchain software production still lacks a disciplined,organized and mature development process,as demonstrated by the many and(in)famous failures and frauds occurred in recent *** this paper we present ABCDE,a complete method addressing blockchain software *** method considers the software integration among the blockchain components—smart contracts,libraries,data structures—and the out-of-chain components,such as web or mobile applications,which all together constitute a complete DApp *** advocate for ABCDE the use of agile practices,because these are suited to develop systems whose requirements are not completely understood since the beginning,or tend to change,as it is the case of most blockchain-based *** is based on Scrum,and is therefore iterative and *** Scrum,we kept the requirement gathering with user stories,the iterative-incremental approach,the key roles,and the *** main difference with Scrum is the separation of development activities in two flows—one for smart contracts and the other for out-of-chain software interacting with the blockchain—each performed iteratively,with integration activities every 2–3 *** makes explicit the activities that must be performed to design,develop,test and integrate smart contracts and out-of-chain software,and documents the smart contracts using formal diagrams to help development,security assessment,and maintenance.A diagram derived from UML class diagram helps to effectively model the data structure of smart contracts,whereas the exchange of messages between the entities of the system is modeled using a modified UML sequence *** proposed method has also specific activities for security assessment and gas optimization,through systematic use of patterns and *** focuses on Ethereum blockchain and its

关键词： Blockchain Smart contracts Blockchain-oriented software engineering UML DApp design

Long-term Regional Dynamic Sea Level Changes from CMIP6 Projections

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Advances in Atmospheric Sciences 2021年第2期38卷 157-167页

作者： Bruno FERRERO Marcos tonelli Fernanda MARCELLO Ilana WAINER University of São Paulo São Paulo 05508120Brazil

Anthropogenic climate forcing will cause the global mean sea level to rise over the 21st ***,regional sea level is expected to vary across ocean basins,superimposed by the influence of natural internal climate ***,we address the detection of dynamic sea level(DSL)changes by combining the perspectives of a single and a multimodel ensemble approach(the 50-member CanESM5 and a 27-model ensemble,respectively,all retrieved from the CMIP6 archive),under three CMIP6 projected scenarios:SSP1-2.6,SSP3-7.0 and *** ensemble analysis takes into account four key metrics:signal(S),noise(N),S/N ratio,and time of emergence(ToE).The results from both sets of ensembles agree in the fact that regions with higher S/N(associated with smaller uncertainties)also reflect earlier *** DSL signal is projected to emerge in the Southern Ocean,Southeast Pacific,Northwest Atlantic,and the *** common for both sets of ensemble simulations show that while S progressively increases with increased projected emissions,N,in turn,does not vary substantially among the SSPs,suggesting that uncertainty arising from internal climate variability has little dependence on changes in the magnitude of external *** changes are greater and quite similar for the scenarios SSP3-7.0 and SSP5-8.5 and considerably smaller for the SSP1-2.6,highlighting the importance of public policies towards lower emission scenarios and of keeping emissions below a certain threshold.

关键词： dynamic sea level CMIP6 sea level rise signal-to-noise time of emergence

Highly efficient Nd:(La_xGd_(1-x))_3Gd_5O_(12) laser operation at 1.33 μm

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Chinese Optics Letters 2016年第2期14卷 51-54页

作者：贾志泰尹延如杨合张百涛何京良 mauro.tonelli 陶绪堂 State Key Laboratory of Crystal Materials Shandong University Key Laboratory of Functional Crystal Materials and Device (Shandong University Ministry of Education) NEST-CNR and Dipartimento di Fisica Università di Pisa

The continuous wave （CW） and passively Q-switched （PQS） performances of diode-pumped Nd：（LaxGd1-x）3Gd5O12 （Nd：LaGGG） at 1.33 μm are achieved for the first time to our knowledge. The maximum CW output power of 5.1 W is obtained with the optical-optical conversion efficiency of 25.3% and the slope efficiency of 26.6%. In the PQS operation, by using the V3＋：YAG crystal as the saturable absorber, the maxi- mum average output power, shortest pulse width, largest pulse energy, and highest peak power are measured to be 1.1 W, 27.54 ns, 75.78 μJ, and 2.44 kW, respectively.

关键词： Optics Physics