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Crystal structure and infrared spectrum of thallium holmium polyphosphate, TlHo(PO_3)_4

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Journal of Rare Earths 2008年第6期26卷 765-769页

作者： Karima Horchani-Naifer Jaouher Amami Mokhtar Férid Unité de Recherches de Matériaux de Terres Rares Centre National de Recherches en Sciences des Matériaux

Crystals of thallium-holmium polyphosphate T1Ho（PO3）4 were grown by flux method technique and characterized by single crystal X-ray diffraction. Structure of T1Ho（PO3）4 was solved for the first time, and it crystallized in the monoclinic P21/n space group with the following unit-cell dimensions： a=1.02225（3） nm, b=0.88536（2） nm, c=1.09541（4） nm, β=105.888（1）°, V=0.95354（5） nm^3 and Z=4. The crystal structure was solved from 2174 independent reflections with final R1（F^2）=0.0442 and Rw（F^2）=0.0861 refined with 164 parameters. The atomic arrangement could be described as a long chain polyphosphate organization. Holmium atoms had eightfold coordination. The structure of T1Ho（PO3）4 consisted of HoO8 polyhedra sharing oxygen atoms with phosphoric group PO4. Infrared spectrum was investigated at room temperature in the frequencies range, 350--4000 cm^-1, showing some characteristic vibration bands of infinite chain structure of PO4 tetrahedra linked by bridging oxygen.

关键词： polyphosphate holmium crystal structure infrared spectroscopy rare earths

Conduction properties of condensed lanthanum phosphates:la(PO_3)_3 and laP_5O_(14)

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Journal of Rare Earths 2010年第3期28卷 321-328页

作者： Ines Hammas Karima Horchani-Naifer Mokhtar Férid Research Unit of Rare Earth Materials National Research Center in Sciences of MaterialsB.P.95 Hammam-Lif2050Tunisia

Single crystals of laP3O9·3H2O were prepared using a classical method of aqueous chemistry whereas those of the ultraphosphate laP5O14 were obtained by flux *** treatment of laP3O9·3H2O up to 700 °C allowed us to obtain the lanthanum polyphosphate la(PO3)*** conductivity as well as the vibrational study of the lanthanum ultraphosphate and polyphosphate were analysed in order to explain the mechanism of *** energies of 0.45 and 0.84 eV,deduced from the Arrhenius relation,were r...

关键词： condensed lanthanum phosphates electrical conductivity Grotthuss mechanism rare earths

Combustion synthesis and luminescence properties of laPO4： Eu （5%）

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Journal of Rare Earths 2009年第2期27卷 182-186页

作者： Mounir Ferhi Karima Horchani-Naifer Mokhtar Férid Research Unit of Rare Earth Materials National Research Center in Sciences of Materials B.P. 95 Hammam-Lif 2050 Tunisia

Rare earth doped materials are an important type of phosphors due to their excellent performance such as stability at high temperature and light emission covering the entire visible domain. The combustion synthesis at acid pH of the monoclinic laPO4： Eu（5%） powders was described. A mixture of la（NO3）3·6H2O, EuCly6H2O and （NH4）2HPO4 was used as anion precursor and glycin as fuel. The synthesis was followed by structure, morphology characterisation and luminescent properties of the obtained compound. The room temperature emission measurements under ultraviolet excitation at 254 nm were made for the emission transition ^5D0→^7FJ of this phosphor. The CIE （Commission Intemationale de l＇Eclairage） chromatic coordinates, dominant wavelength and colour purity were determined and compared to other luminescent materials obtained by other methods.

关键词： rare earth phosphates combustion optical materials luminescence chromaticity

Synthesis and crystal structure of sodium praseodymium polyphosphate, NaPr(PO_3)_4

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Journal of Rare Earths 2009年第1期27卷 1-3页

作者： K.Horchani-Naifer J.Amami M.Férid Research Unit of Rare Earth Materials National Research Center in Sciences of Materials

Reaction of Na2CO3, Pr6O11 and H3PO4 gave the sodium praseodymium polyphosphate NaPr（PO3）*** title compound crystallized in the monoclinic P21/n space group with a=0.9965（4） nm, b=1.31437（4） nm, c=0.72271（3） nm, β=90.429（3）°, V=0.9465（4） nm3, Z=4, R=0.0493 and wR=0.1266 for 1855 independent *** structure of NaPr（PO3）4 consisted of PrO8 polyhedra sharing oxygen atoms with phosphoric group PO4 to form a three-dimensional framework, delimiting intersecting tunnels in which the sodium ion was *** Na＋ ion was bonded to seven oxygen atoms.

关键词： polyphosphate praseodymium crystal structure infrared spectroscopy rare earths

Impact of grain size,Pr3+ concentration and host composition on non-contact temperature sensing abilities of polyphosphate nano- and microcrystals

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Journal of Rare Earths 2019年第8期37卷 812-818,I0001页

作者： S.Gharouel l.Marciniak A.lukowiak W.Strek K.Horchani-Naifer M.Férid Research Unit of Rare Earth Materials National Research Center in Sciences of MaterialsB.P.95 Hammam-Lif2050Tunisia b Institute of Low Temperature and Structure ResearchPAS Okolna St. 50-422WroclawPoland

In this article,varied praseodymium polyphosphate hosts:MI(li,Na K)Pr(PO3)4 microcrystals and lila1-xPrx(PO3)4(x = 0.01 ^-1)nanocrystals were successfully synthesized by the flux method and the coprecipitation technique,*** size of stoichiometric nanocrystals of liPr(PO3)4 was tuned by the te mpe rature of thermal treatment in range of 35-145 *** order to dete rmine the most suitable material for the non-contact optical thermometric applications,the temperature sensing measurements were carried out by using luminescence intensity ratio(lIR)of emission bands corresponding to the ^3 P1→ ^3H5 and ^3P0→ ^3 H5 electronic transitions of Pr3+ ions into the 123-423 K temperature *** influence of the host material composition of MⅠ(li,Na,K)Pr(PO3)4 microcrystals on the sensitivity of luminescent thermometers was *** is found that the sensitivity of lithium praseodymium polyphosphate is the highest of all micropowders under ***,it is found that the nanocrystals reveal much higher relative sensitivity in respect to the microcrystalline *** highest sensitivity of lIR temperature sensing is found for liPr(PO3)4 nanocrystals(35 nm grain size)in the whole temperature range,reaching 0.283%/K at 164 *** impact of the average grain size on the sensitivity of lIR based thermometers of liPr(PO3)4 nanocrystals was *** is found that the reduction of the grain size from 145 to 35 nm results in the enhancement of the relative sensitivity from0.156 to 0.240%/K at 223 *** it is found that the high dopant concentration possesses favorable influence on the relative sensitivity of lila1-xPrx(PO3)4 nanocrystalline luminescent thermometers.

关键词： Pr^3+ Temperature sensing luminescence intensity ratio Temperature sensitivity Grain size Dopant concentration

中国古典美学视域下的体育文化探源与概念思辨

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体育科学研究 2024年第3期28卷 1-7页

作者：吕艾文上海体育大学武术学院上海200438

体育文化的历史生成与概念思辨不仅是体育理论研究中的基础性问题,更是探究中国体育文化传承与发展规律的基本途径和重要手段。为解决以往体育起源诸学说过于笼统和宽泛的不足,从体育的生成与发展中把握其本质特征,从而提出“礼乐起源... 详细信息

体育文化的历史生成与概念思辨不仅是体育理论研究中的基础性问题,更是探究中国体育文化传承与发展规律的基本途径和重要手段。为解决以往体育起源诸学说过于笼统和宽泛的不足,从体育的生成与发展中把握其本质特征,从而提出“礼乐起源”的学说,以期在体育的形式和形态中理解其文化智慧与审美理想,对体育进行一种文化与审美的整体观照。中国体育的历史传承深受中国古典哲学思想的熏陶,具有塑造行为、培养情感和提升品格等审美教化功能,并对近代以来中国“体育”术语概念的发展与演变产生了一定的影响力。为摆脱多年来体育概念定义困难的尴尬局面,应坚持历史与逻辑发展相统一的原则,避免对体育概念进行统一划归式的总结,从中国体育的礼乐本质与当代意义出发,坚守其“生命本位”的核心价值与“雅俗共赏”的艺术精神,为我国体育理论研究的深化和提升提供理论创新。

关键词：中国古典美学礼乐文化体育文化体育概念

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凹印制版技术的发展

印刷技术 2004年第20期 20-25页

作者： Siegfried BeiBwenger Max rid 张改梅 HEll公司 K.walter公司北京印刷学院

凹版印刷是一种神奇的印刷工艺,虽然工艺简单,但印刷出来的图像层次丰富、色彩鲜艳、清晰度好、质量高.惟一的挑战就是凹版滚筒的制作有一定的难度.从1446年第一支镀铜凹版滚筒的问世,至今已有几百年的历史了,随着科学技术的发展,凹印... 详细信息

凹版印刷是一种神奇的印刷工艺,虽然工艺简单,但印刷出来的图像层次丰富、色彩鲜艳、清晰度好、质量高.惟一的挑战就是凹版滚筒的制作有一定的难度.从1446年第一支镀铜凹版滚筒的问世,至今已有几百年的历史了,随着科学技术的发展,凹印制版技术越来越先进,同时也日趋复杂.期间先后经历了多个发展阶段,最早出现的是手工雕刻凹版,后来又有了针刻凹版、镂刻凹版、腐蚀凹版以及直接雕刻凹版.各种五花八门的凹印制版工艺,其核心问题和最基本的原理就是采用何种成像方式,是雕刻成像还是在铜层表面进行腐蚀.

关键词：凹印制版技术发展凹版印刷电子雕刻制版技术传统照相凹印制版技术照相直接加网制版技术