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Taming heat with tiny pressure

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The Innovation 2024年第2期5卷 70-78页

作者： Kun Zhang Zhe Zhang Hailong Pan Haoyu Wang Xueting Zhao Ji Qi Zhao Zhang Ruiqi Song Chenyang Yu Biaohong huang Xujing Li huaican Chen Wen Yin Changlong Tan weijin hu Michael Wüubbenhorst Jiangshui Luo Dehong Yu Zhidong Zhang Bing Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Laboratory for Soft Matter and Biophysics Department of Physics and AstronomyKU Leuven3001 LeuvenBelgium Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China College of Materials Science and Engineering Sichuan UniversityChengdu 610064China School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150080China Australian Nuclear Science and Technology Organisation Lucas HeightsNSW 2234Australia

Heat is almost *** electricity,which can be easily manipulated,the current ability to control heat is still highly limited owing to spontaneous thermal dissipation imposed by the second law of *** illumination and pressure have been used to switch endothermic/exothermic responses of materials via phase transitions;however,these strategies are less cost-effective and ***,we spectroscopically demonstrate the glassy crystal state of 2-amino-2-methyl-1,3-propanediol(AMP)to realize an affordable,easily manageable approach for thermal energy *** supercooled state of AMP is so sensitive to pressure that even several megapascals can induce crystallization to the ordered crystal,resulting in a substantial temperature increase of 48 K within 20 ***,we demonstrate a proof-of-concept device capable of programable heating with an extremely high work-to-heat conversion effi-ciency of*** delicate and efficient tuning of heat may remarkably facilitate rational utilization of waste heat.

关键词： illumination thermal rational

Electrical and optical modulation on ferroelectric properties of P(VDF-TrFE) thin film capacitors

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Journal of Materials Science & Technology 2019年第10期35卷 2194-2199页

作者： Xiaohan Li Biaohong huang weijin hu Zhidong Zhang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences(IMRCAS)Shenyang110016China School of Material Science and Engineering University of Science and Technology of China(USTC)Anhui230026China

Modulating the ferroelectric properties of P(VDF-TrFE) polymers both electrically and optically could open up new opportunities for their applications in non-volatile memories and sensors. Here by using the Nb:SrTiO3 semiconductor as electrode compared with metal Au electrode, we report on the modulation of ferroelectric properties of P(VDF-Tr FE) thin film capacitors both by electric field and UV light. A ferroelectric hysteresis loop shift together with the asymmetric switching behavior has been observed when using semiconducting electrode, which could be explained by the band alignment model based on interfacial charge screening. On the basis of band bending near the ferroelectric/semiconductor interface,we could further modulate the ferroelectric switching behaviors reversibly by UV light illumination. Our research provides a new route to engineer the ferroelectric properties of P(VDF-TrFE) polymer thin film capacitors, promising their applications in optoelectronic devices.

关键词： P(VDF-TrFE) Ferroelectric Semiconducting electrode Coercive field Switching dynamics UV-light

The effects of Eu^(3+) doping on the epitaxial growth and photovoltaic properties of BiFeO_(3) thin films

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Journal of Materials Science & Technology 2022年第11期106卷 49-55页

作者： Dingshuai Feng Biaohong huang Lingli Li Xiaoqi Li Youdi Gu weijin hu Zhidong Zhang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

Nowadays,photovoltaic effect has been widely studied in various ferroelectric materials due to its ap-plications as optoelectronic *** this work,with BiFeO_(3)(BFO)films as the photovoltaic materials,we report the effects of Eu^(3+)doping content on the phase structure,ferroelectric and optical properties of BFO films grown on Ca_(0.96) Ce_(0.04) MnO_(3)/YAlO_(3)(001)*** found that a small doping level of 0.05 could induce a phase change of BFO from tetragonal to rhombohedral,due to the shrinking of the lattice upon Eu^(3+)doping and the breaking of surface terrace structure induced by Ca_(0.96) Ce_(0.04) MnO_(3) *** results in a sharp band gap reduction from 3.30 eV to 2.60 eV,and a decrease in the coercivity of ferroelectric polarization *** on these findings,we investigate the photovoltaic effects of ITO/Eu_(x) Bi_(1-x) FeO_(3)/Ca_(0.96) Ce_(0.04) MnO_(3) vertical *** is found that the short-circuit current density(J_(sc))decreases with increasing Eu^(3+)doping,whereas the open-circuit voltage(V_(oc))first increases to a level of 0.1 V and then decreases with further Eu^(3+)*** could be explained by the combined ef-fect of Schottky-junction and depolarization field on the photovoltaic *** research suggests that a moderate Eu^(3+)doping is helpful for enhancing the photovoltaic effect of BFO thin film devices.

关键词： Ferroelectric Photovoltaic effect BiFeO_(3) Eu^(3+)doping Band gap

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同杆并架双回线路模变换分析

电网技术 1998年第1期22卷 25-27,30页

作者：何奔腾胡为进浙江大学电机系

本文通过对同杆双回线的模变换分析，得出了其模变换表达式，同时也得出了几种特殊的对应于普通三相系统模变换的同杆双回线变换矩阵。其中，推出的复数矩阵具有零元素多，运算简单等优点，而两种实数矩阵类Ｃｌａｒｋ和类Ｋａｒｒａｎ... 详细信息

本文通过对同杆双回线的模变换分析，得出了其模变换表达式，同时也得出了几种特殊的对应于普通三相系统模变换的同杆双回线变换矩阵。其中，推出的复数矩阵具有零元素多，运算简单等优点，而两种实数矩阵类Ｃｌａｒｋ和类Ｋａｒｒａｎｂａｎｅｒ变换矩阵除具有上述优点外，且其运算简单物理意义明确，可运用于各种稳态及暂态电气量。

关键词：同杆并架双回线路模变换继电保护线路保护

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金融支持滇中产业聚集区发展研究

西部金融 2014年第3期 63-66,88页

作者：雷一忠胡维金中国人民银行昆明中心支行云南昆明650021

建设滇中产业聚集区是云南省委、省政府作出的重大战略抉择。本文根据云南省委、省政府制定的发展目标,使用投资效果系数法测算了2013-2020年滇中产业聚集区的固定资产投资需求,在此基础上分析了金融支持滇中产业聚集区发展面临的困难... 详细信息

建设滇中产业聚集区是云南省委、省政府作出的重大战略抉择。本文根据云南省委、省政府制定的发展目标,使用投资效果系数法测算了2013-2020年滇中产业聚集区的固定资产投资需求,在此基础上分析了金融支持滇中产业聚集区发展面临的困难和问题,认为应该通过完善投融资体制、创新开发模式、加强市场化融资和提升投融资环境等措施为滇中产业聚集区发展提供金融支持。

关键词：滇中产业聚集区投资效果系数固定资产投资

考虑边端效应及参数变化的直线感应电机MRAS速度观测方法

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铁道科学与工程学报 2024年第4期21卷 1591-1601页

作者：胡海林陈维金虞诗焱丰富汪涛江西理工大学电气学院江西赣州341000 国家铁路局磁浮技术铁路行业重点实验室上海201804 江西省磁悬浮技术重点实验室江西赣州341000

以轨道交通直线感应电机(Linear Induction Motor,LIM)牵引驱动系统速度观测器为研究对象,针对边端效应及电机参数变化导致辨识结果实时性、鲁棒性不足的问题,提出一种基于二阶超螺旋滑模的改进模型参考自适应系统(Model Reference Adap... 详细信息

以轨道交通直线感应电机(Linear Induction Motor,LIM)牵引驱动系统速度观测器为研究对象,针对边端效应及电机参数变化导致辨识结果实时性、鲁棒性不足的问题,提出一种基于二阶超螺旋滑模的改进模型参考自适应系统(Model Reference Adaptive System,MRAS)速度观测方法。首先,以计及动态边端效应的初次级电压电流磁链方程为核心,设计直线感应电机标准MRAS速度观测器,降低边端效应对速度辨识性能的影响。然后,进一步分析初级集肤效应和初次级横向错位对标准MRAS速度观测器辨识性能的影响。在此基础上,基于二阶超螺旋算法对MRAS参考模型进行改进,利用主滑模面和辅助滑模面对次级磁链观测的干扰项进行补偿,同时抑制由于滑模算法引入的系统抖振,提高了速度观测器的鲁棒性和动态性能。最后,搭建仿真和硬件在环实验环境进行算法验证。实验结果表明:励磁互感及其他电机参数随边端效应修正因子变化,标准MRAS观测器在突加负载、引入测量误差和电机参数突变的工况下,速度辨识误差明显;改进的MRAS观测器能够实现直线感应电机速度的快速、准确辨识,基于该速度观测器的矢量控制策略,在突加负载、引入测量误差和电机参数突变的工况下,控制性能满足设计要求。研究结果能为轨道交通直线感应电机无速度传感器牵引驱动系统的研究提供一定借鉴。

关键词：直线感应电机无速度传感器模型参考自适应系统边端效应二阶超螺旋滑模算法

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西安地区的连阴雨模糊数学模型

高等数学研究 2015年第4期18卷 90-92页

作者：沈志军支宇堃胡卫金咸阳宝石钢管钢绳有限公司陕西咸阳712000 西安市临潼区气象局陕西临潼710600

为更好地服务于治污减霾和汛期气象工作,利用数学模型和模糊数学的相关知识,对西安及附近地区连阴雨的规律进行了分类.表明模糊数学可应用于识别连阴雨天气的规律.

关键词：数学模型连阴雨模糊数学西安

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钢坯定重动态智能调控技术探讨

山西冶金 2024年第7期47卷 185-187页

作者：丁建军詹卫金胡洪首钢长治钢铁有限公司山西长治046031

近年来,随着棒材生产多线切分常态化,高速棒材生产技术及钢坯免加热直接轧制技术日益成熟,并得到广泛应用。在棒材生产过程中,许多企业实现了钢坯快速输送并直接轧制,生产效率大大提高。但是,轧钢生产线要求连铸工序对钢坯进行定重控制... 详细信息

近年来,随着棒材生产多线切分常态化,高速棒材生产技术及钢坯免加热直接轧制技术日益成熟,并得到广泛应用。在棒材生产过程中,许多企业实现了钢坯快速输送并直接轧制,生产效率大大提高。但是,轧钢生产线要求连铸工序对钢坯进行定重控制,采用跨单位电话通知方式进行人工调整,响应速度慢、稳定性差,难以满足快节奏的生产模式,导致轧后通尺量大,严重制约成材率指标的提高。因此,从连铸到轧钢工序系统考虑,通过建立数学模型,运用在线检测、信息计算技术,实现生产过程的动态调整,达到无人干预并自动控制的目的,为生产线实现高效智能制造提供切实可行的技术控制方法。

关键词：坯耗指标定重数学模型在线检测动态调整成材率指标

Effect of OH^- on fluorescence properties in 1.5-1.6 μm for Er:Yb:YCOB crystal

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Journal of Rare Earths 2019年第9期37卷 924-930,I0001页

作者： Degao Zhong Chen hu Shakir Ullah hui Xu Jianhong Li Fei You Dongjuan Wang Shijia Sun weijin Kong Jie Tang Zhenghe Yu Bing Teng College of Physics Qingdao UniversityQingdao 266071China National Demonstration Center for Experimental Applied Physics Education (Qingdao University) Qingdao 266071China CRYSTECH Inc. Qingdao 266107China Institute o f Engineering Materials Weifang Business Vocational CollegeWeifang 262234China

FTIR absorption spectra indicate that H^+can easily enter the crystal structure and form OH^-centers in Er:Yb:YCOB and O-H bonds prefer to lie in the a-c *** our current studied concentration level,crystal samples with higher OH-abso rption coefficie nts demonstrate stro nger fluo rescence intensity and longer fluorescence lifetime at 1535 *** the stretching vibration energy of OH-group approximately corresponds to the energy gap between the 4 I11/2 and 4 I13/2 levels of Er^3+,and thus,OH^-ions can shorten the fluorescence lifetime of Er^3+-4I11/2 level by the phonon-assisted cross-relaxation process between the Er^3+and *** curre nt results confirm that a certain conte nt of OH ions can enhance the ene rgy transfer process from Yb^3+to Er^3+and subsequently promote fluorescence output in 1.5-1.6μm.

关键词： Er:Yb:YCOB crystal OH^-ions Fluorescence output efficiency Energy transfer process Rare earths