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Optical spectroscopy and crystal-field strength of Cr^(3+) in various solid matrixes

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Rare Metals 2006年第1期25卷 51-57页

作者： XIA Haiping wang jinhao wang Hongyin ZHANG Jianli ZHANG Yuepin XU Tiefeng The Laboratory of Photo-electronic Materials Ningbo University Ningbo 315211 China

The Cr^3＋：BeAl2O4 crystal, Cr^3＋：LiNbO3 crystal, and ZnO-Al2O3-SiO2 glass-ceramic were obtained by the Czochralski technique, Bridgman method, and melting processing, respectively. The optical absorption and emission spectra of the above Cr^3＋-incorporated solid-state materials were recorded. The technical parameters for growing high-quality Cr^3＋：BeAl2O4 and Cr^3＋：LINbO3 crystals were obtained. The results indicate that the optical absorption and fluorescence spectra of Cr^3＋ show quite a few differences in various matrixes. The sharp line emissions were observed in the Cr^3＋：BeAl2O4 and Cr^3＋：LiNbO3 crystals. The crystal-field parameters （Dq） for Cr^3＋. in different matrixes were calculated from their corresponding spectra. It is indicated that Cr^3＋：BeAl2O4 and Cr^3＋：LiNbO3 belong to the high-field site crystal, while the Cr^3＋ ZnO-Al2O3-SiO2 glass and glass-ceramic belong to the weak-field site crystal.

关键词： special functional inorganic materials optical spectroscopy optical measurement Cr^3+ ion matrix

Migratable Power System Transient Stability AssessmentMethod Based on Improved XGBoost

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Energy Engineering 2024年第7期121卷 1847-1863页

作者： Ying Qu jinhao wang Xueting Cheng Jie Hao Weiru wang Zhewen Niu Yuxiang Wu Electric Power Science Research Institute State Grid Shanxi Electric Power CompanyTaiyuan030000China Department of Electrical and Power Engineering Taiyuan University of TechnologyTaiyuan030024China

The data-driven transient stability assessment(TSA)of power systems can predict online real-time prediction by learning the temporal features before and after ***,the accuracy of the assessment is limited by the quality of the data and has weak *** on this,this paper proposes a method for TSA of power systems based on an improved extreme gradient boosting(XGBoost)***,the gradient detection method is employed to remove noise interference while maintaining the original time series *** this basis,a focal loss function is introduced to guide the training of theXGBoostmodel,enhancing the deep exploration of minority class samples to improve the accuracy of the model ***,to improve the generalization ability of the evaluation model,a transfer learning method based on model parameters and sample augmentation is *** simulation analysis on the IEEE 39-bus system demonstrates that the proposed method,compared to the traditional machine learning-based transient stability assessment approach,achieves an average improvement of 2.16%in evaluation ***,under scenarios involving changes in topology structure and operating conditions,the accuracy is enhanced by 3.65%and 3.11%,***,the model updating efficiency is enhanced by 14–15 times,indicating the model’s transferable and adaptive capabilities across multiple scenarios.

关键词： Transient stability assessment data-driven segmented focusing approximation portability

Incorporated Organic Modified Ag Nanoparticles in Ormocer

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Journal of Materials Science & Technology 2004年第4期20卷 477-478页

作者： Haiping XIA, Jianli ZHANG, jinhao wang and Qiuhua NIELaboratory of Photo-electronic Materials, Ningbo University, Ningbo 315211, China Lab. of Photo-electronic Mat. Ningbo Univ. Ningbo 315211 China

Ag nanoparticles coated trisodium citrate were incorporated in ormocer by sol-gel method. The doping concentration of Ag in ormocer is about 1.0% in weight. The HRTEM demonstrated that the particles disperse in ormoce... 详细信息

关键词： Colloid Ag particle Sol-gel chemistry Ormocer

Fullerenol-containing Materials Derived by Sol-gel Processing

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Journal of Materials Science & Technology 2004年第5期20卷 555-557页

作者： Haiping XIA, Zhaoyang JIANG, Jianli ZHANG, jinhao wang, Yuepin ZHANG and Qiuhua NIELaboratory of Photo-electronic Materials, Ningbo University, Ningbo 315211, China Lab. of Photo-Electron. Mat. Ningbo Univ. Ningbo 315211 China

Water soluble fullerenols were synthesized and incorporated in SiO2, SiO2-TiO2, GPTMS-SiO2, GPTMS-ATPS inorganic and organic-inorganic materials by sol-gel processes. The maximum concentrations of C60(OH)n and C70(OH)n in the obtained SiO2 gels were estimated to be about 0.6% and 1.5% in weight, respectively. The characteristics of the UV/visible spectra of fullerenols in H2O and various gels were measured and compared. The thermal stability of fullerenols in gels was investigated with differential thermal analysis (DTA). The results indicate that the absorption features of fullerenols in solid gels are similar to those in H2O and the fullerenols in SiO2 are stable at 400℃. The optical limiting effect of the fullerenols was investigated preliminarily.

关键词： Water soluble fullerenol Sol-gel chemistry Thermal stability Optical properties

基于电压矩阵的跟网变流器无锁相环控制的本质特征与提升策略

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电力系统自动化 2024年第21期48卷 138-147页

作者：吴超赵统王尽颢王勇上海交通大学电子信息与电气工程学院上海市200240

弱电网下跟网变流器由于锁相环引起的负阻特性容易造成振荡现象。针对锁相环的提升策略已有较多研究,其中,基于电压矩阵的同步控制策略因其不存在锁相环受到广泛关注,但关于其稳定性缺乏严格的理论证明。文中分析表明,基于电压矩阵的无... 详细信息

弱电网下跟网变流器由于锁相环引起的负阻特性容易造成振荡现象。针对锁相环的提升策略已有较多研究,其中,基于电压矩阵的同步控制策略因其不存在锁相环受到广泛关注,但关于其稳定性缺乏严格的理论证明。文中分析表明,基于电压矩阵的无锁相环控制策略本质上是基于并网点电压反正切计算的开环定向方式,虽然去除锁相环但不能提高稳定性。因为该策略并没有降低电压扰动给电流控制带来的负阻特性,所以如何降低并网点电压扰动对于电流控制的影响是提升弱电网下跟网变流器稳定性的关键。因此,提出自适应带通滤波器来降低同步环节的带宽,从而提升跟网变流器在弱电网下的稳定性。最后,通过阻抗模型和实验结果验证了理论分析的正确性和所提策略的有效性。

关键词：跟网变流器小干扰稳定宽频振荡锁相环电压矩阵阻抗模型

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可变拓扑的改进型交直流混合微电网

电力系统自动化 2020年第18期44卷 147-154页

作者：孟润泉杜毅韩肖清王磊王金浩王鹏电力系统运行与控制山西省重点实验室(太原理工大学) 山西省太原市030024 国网山西省电力科学研究院山西省太原市030000

为提高配电网非理想工况下并网的交直流混合微电网(HMG)的运行性能,提出一种可变拓扑的交直流HMG及其控制策略。首先,在HMG交流母线与配电网之间插入了串联补偿变压器(SCT),并设置对应的双功能变换器在并网运行时控制SCT实现电压补偿,... 详细信息

为提高配电网非理想工况下并网的交直流混合微电网(HMG)的运行性能,提出一种可变拓扑的交直流HMG及其控制策略。首先,在HMG交流母线与配电网之间插入了串联补偿变压器(SCT),并设置对应的双功能变换器在并网运行时控制SCT实现电压补偿,而在孤岛运行时用作HMG交直流母线接口变换器。其次,在分析电路拓扑和工作模式的基础上,设计了双功能变换器与交直流母线接口变换器的解耦协调控制策略。最后,仿真和实验结果表明,在配电网电压波动、暂降和暂升工况下,所提方案能够使HMG交流母线电压保持稳定,提高了HMG的故障穿越能力和供电质量。

关键词：微电网交直流变换器串联补偿变换器故障穿越能力电能质量

GeO_2对Eu^(3+)掺杂Bi_2O_3-B_2O_3-ZnO玻璃光谱性质的影响

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光学学报 2005年第11期25卷 1515-1518页

作者：夏海平章践立王金浩张约品宁波大学光电子功能材料重点实验室宁波315211

用高温融熔法制备了Eu3+掺杂摩尔分数为1%的(60-χ)Bi2O3-χGeO2-30B2O3-10ZnO(摩尔分数χ=5,10,20,30)系统玻璃。测定了玻璃的差热分析曲线、发射光谱与激发光谱。从发射光谱与稀土Eu3+离子光学跃起矩阵元的特点,计算了Eu3+光学跃迁的... 详细信息

用高温融熔法制备了Eu3+掺杂摩尔分数为1%的(60-χ)Bi2O3-χGeO2-30B2O3-10ZnO(摩尔分数χ=5,10,20,30)系统玻璃。测定了玻璃的差热分析曲线、发射光谱与激发光谱。从发射光谱与稀土Eu3+离子光学跃起矩阵元的特点,计算了Eu3+光学跃迁的参量Ω2与Ω4。结果显示强度参量Ω2与Ω4随着GeO2量的增加而增加,表明材料的对称性降低,Eu-O键强增加,共价性增加。玻璃的软化温度随GeO2组份的增加而提高。在GeO2摩尔分数达10%时,析晶起始温度与玻璃软化温度的差达最大,约146℃,表明该玻璃的热稳定性最好。

关键词：光谱学 Eu^3+掺杂铋基光学玻璃 Judd-Ofelt理论氧化锗强度参量热稳定性

Growth and Optical Spectra of Zn∶Er∶LiNbO_3 Crystals by Bridgman Method

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Journal of Rare Earths 2005年第5期23卷 563-563页

作者： wang jinhao Zhang Jianli Zhang Yuepin Xia Haiping Laboratory of Photo-Electronic Matedals Ningbo University Ningbo 315211 China

The growth of LiNbO3 single crystal with Er^3＋/Zn^2＋ co-doped by the bridgman method and the characteristics of absorption spectra and fluorescence spectra were reported. By means of the optimized con- ditions such as growth rate of 0.8 - 1.5 mm · h^- 1, temperature gradient about 30 - 35℃ ·cm^-1 across the solid-liquid interface and sealed platinum, large size crystals containing Zn^2＋（3%） and Er^3＋（0.6%） with good optical quality were obtained. X-ray diffraction and DTA were used to characterize the crystals. The results indicate that the concentration of Er^3＋ ions in crystals decrease along the growth direction, the absorption intensity and the fluorescence intensity ions also decrease along the growth direction. of Er^3＋ However, for the upper part crystal, the upconversion fluorescence intensity is higher than that of the lower part crystal excited with 800 or 970 nm pump. The effects of crystal lattice, structure defect and effective segregation of Er^3＋ ions were discussed in respect to the variations were discussed of upconversion fluorescence intensity.

关键词： LiNbO3 crystal Er^3 +/Zn^2 + co-doping bridgman method upconverison fluorescence rare earths

Co^(2+),Zn^(2+)双掺杂铌酸锂晶体的坩埚下降法生长及其光谱特性(英文)

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硅酸盐学报 2005年第11期33卷 1326-1329页

作者：夏海平王金浩章践立张约品宁波大学光电子功能材料重点实验室宁波315211

在LiNbO3中掺入0.1%(摩尔分数,下同)的CoO与3%,6%的ZnO,采用坩埚下降法技术生长了双掺杂的Co2+∶Zn2+∶LiNbO3晶体。用X射线衍射与差热分析表征了获得的晶体。测定了晶体不同部位在350~2 500 nm波段的吸收光谱。研究表明:Co离子位于LiN... 详细信息

在LiNbO3中掺入0.1%(摩尔分数,下同)的CoO与3%,6%的ZnO,采用坩埚下降法技术生长了双掺杂的Co2+∶Zn2+∶LiNbO3晶体。用X射线衍射与差热分析表征了获得的晶体。测定了晶体不同部位在350~2 500 nm波段的吸收光谱。研究表明:Co离子位于LiNbO3晶体的崎变的氧八面体中,呈现+2价,沿着生长方向Co2+在晶体中的浓度逐渐减少。ZnO的掺杂有效地抑制了Co2+离子在晶体中的掺入,使得Co2+在晶体中浓度的分布变得均匀。同时发现:ZnO的掺入使得上部晶体的熔点升高。从化学组分的角度解释了产生熔点变化的原因。观测到了750 nm波长的荧光发射带。

关键词：钴锌双掺杂铌酸锂晶体坩埚下降法熔点光谱