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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

Complement-dependent neuroinflammation in spinal cord injury:from pathology to therapeutic implications

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Neural Regeneration Research 2025年第5期20卷 1324-1335页

作者： Hassan Saad Bachar El Baba Ali Tfaily firas Kobeissy Juanmarco Gutierrez Gonzalez Daniel Refai Gerald R.Rodts Christian mustroph David Gimbel Jonathan Grossberg Daniel L.Barrow matthew f.Gary Ali m.Alawieh Department of Neurosurgery Emory University School of MedicineAtlantaGAUSA Department of Neurology Yale UniversityNew HavenCTUSA Center for Neurotrauma Multiomics&Biomarkers(CNMB)Morehouse School of MedicineAtlantaGAUSA

Spinal cord injury remains a major cause of disability in young adults,and beyond acute decompression and rehabilitation,there are no pharmacological treatments to limit the progression of injury and optimize recovery in this *** the thorough investigation of the complement system in triggering and propagating cerebral neuroinflammation,a similar role for complement in spinal neuroinflammation is a focus of ongoing *** this work,we survey the current literature investigating the role of complement in spinal cord injury including the sources of complement proteins,triggers of complement activation,and role of effector functions in the *** study relevant data demonstrating the different triggers of complement activation after spinal cord injury including direct binding to cellular debris,and or activation via antibody binding to damage-associated molecular *** effector functions of complement have been implicated in spinal cord injury,and we critically evaluate recent studies on the dual role of complement anaphylatoxins in spinal cord injury while emphasizing the lack of pathophysiological understanding of the role of opsonins in spinal cord *** this pathophysiological review,we systematically review the different translational approaches used in preclinical models of spinal cord injury and discuss the challenges for future translation into human *** review emphasizes the need for future studies to dissect the roles of different complement pathways in the pathology of spinal cord injury,to evaluate the phases of involvement of opsonins and anaphylatoxins,and to study the role of complement in white matter degeneration and regeneration using translational strategies to supplement genetic models.

关键词： complement neuroinflammation neuroplasticity regeneration spinal cord injury targeted therapy

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

Non-destructive corrosion study on a magnesium alloy with mechanical properties tailored for biodegradable cardiovascular stent applications

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Journal of materials Science & Technology 2021年第7期66卷 128-138页

作者： Changhong Cai marta m.Alves Renbo Song Yongjin Wang Jingyuan Li School of materials Science and Engineering University of Science and Technology BeijingBeijing100083China Centro de Qufmica Estrutural Instituto Superior TecnicoUniversidade de LisboaAv.Rovisco Pais1049-001LisboaPortugal

Anmg-2Zn-0.6Zr-0.6Nd alloy for biodegradable cardiovascular stent applications was prepared through indirect extrusion. The alloy exhibited a superior combination of tensile yield strength(TYS), ultimate tensile strength(UTS) and elongation(EL) of about 269 mPa, 298 mPa and 25.6 %, respectively. In addition,the non-destructive electrochemical frequency modulation(Efm) technique was used for the first time to investigate the corrosion behavior of mg alloys combined with electrochemical impedance spectroscopy(EIS) in Dulbecco’s modified Eagle’s medium(DmEm) and in Hank’s solution. Compared with the corrosion rate of 0.07 mm/year in Hank’s solution, lower corrosion rate of 0.03 mm/year was achieved in DmEm. The significant differences between the corrosion rate trends were discussed and related with the composition of the corrosion layer formed. Depending on the biomimetic fluids tested, different corrosion products were precipitated on the alloy’s surface: a compact and homogeneous layer of mg_(x)Ca_(y)(PO_(4))_(z) and Zn(OH)_(2) and organic compounds was formed in DmEm, whereas a partial coverage of mg_(x)Ca_(y)(PO_(4))_(z) and Zn(OH)_(2) was formed in Hank’s solution.

关键词： mg-Zn-Zr-Nd alloy mechanical property Corrosion EIS Efm

EffECT Of GAmmA RAYS IN THE PREPARATION Of POLYmER AND HYDROGEL fROm ACRYLAmIDE mONOmER

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Chinese Journal of Polymer Science 2003年第4期21卷 437-442页

作者： m.m.Alam m.f.mina f.Akhtar NRCD INST AERE GPO Box-3787 Dhaka BangladeshNRCD INST AERE GPO Box-3787 Dhaka BangladeshNRCD INST AERE GPO Box-3787 Dhaka Bangladesh

The formation of polymer and hydrogel from aqueous solutions having 20, 30 and 40% concentrations ofacrylamide monomer by γ-ray irradiation processing in the dose range 0.06-30 kGy using a Co-60 source and theircharacterization have been observed. Polymer conversion and gel fraction are found to depend on radiation doses. Polymerconversion increases with the increase of dose, depending on the solution concentration, where maximum conversion isachieved at 0.18, 0.16 and 0.10 kGy for 20%, 30% and 40% concentrations, respectively. On the other hand, gel fractionincreases with dose from the gel point (0.12 kGy) for all concentrations, where 100% conversion of gel occurs at doses≥5 kGy. Tensile strength, viscosity and molecular weight (m_w) of polymer samples increase with both the dose and theconcentration, showing a high value of m_w up to≈10~8. Swelling of hydrogels under water with respect to time varies due tothe variation of cross-linking density formed in the gels and the maximum swelling mainly occurs within 24 h. A remarkable change of surface morphology reveals characteristic features of monomer, polymer and hydrogel films.

关键词： Polymer Hydrogel γ-Radiation Cross-linking Swelling

SWELLING BEHAVIOR Of ACRYLAmIDE HYDROGEL IN DIffERENT SOLVENTS AND pHs

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Chinese Journal of Polymer Science 2005年第3期23卷 269-274页

作者： m.f.mina m.m.Alam Institute of Nuclear Science and Technology Atomic Energy Research EstablishmentGPO Box-3787Dhaka-1000BangladeshInstitute of Nuclear Science and TechnologyAtomic Energy Research EstablishmentGPO Box-3787Dhaka-1000Bangladesh

Swelling property of acrylamide hydrogels,prepared from aqueous solutions of acrylamide monomer havingconcentrations in the range of 10-60 wt% by ray irradiation method using a Co-60 gamma radiation source at dosesranging 1-30.0 kGy,has been investigated under various swelling *** swelling media were basically solvents(solutions),produced by dissolving methanol,ethanol,glucose,sucrose,sodium chloride and sodium persulfate individuallywith distilled water,and solutions prepared with pHs=3,7 and *** investigation was performed in order to observe theeffect of these solvents and pHs as well as the influence of monomer concentrations,radiation doses and times on swellingbehavior of *** values were found higher for hydrogels prepared with lower monomer concentrations(ca.20 wt%)and radiation doses(ca.5 kGy)and showed a leveling off tendency within 24 *** glucose solvent and the buffersolution of pH=10 revealed significant increase of swelling of hydrogels as compared to other *** areexplained based on crosslinking density in hydrogel,polymer-solvent/polymer-polymer interactions in solutions,permeability of molecules in solutions and ionization capacity of hydrogel in pH.

关键词： Acrylamide Hydrogel Co-60 gamma radiation source Swelling.

Effect of substitution group on dielectric properties of 4H-pyrano [3,2-c] quinoline derivatives thin films

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Chinese Physics B 2016年第7期25卷 440-449页

作者： H m Zeyada f m El-Taweel m m El-Nahass m m El-Shabaan Department of Physics Faculty of Science Damietta University Department of Chemistry Faculty of Science Damietta University Department of Physics Faculty of Education Ain Shams University

The AC electrical conductivity and dielectrical properties of 2-amino-6-ethyl-5-oxo-4-（3-phenoxyphenyl）-5,6-dihydro-4H-pyrano[3, 2-c]quinoline-3-carbonitrile（Ph-HPQ） and 2-amino-4-（2-chlorophenyl）-6-ethyl-5-oxo-5,6-dihydro-4H-pyrano [3, 2-c] quinoline-3-carbonitrile（Ch-HPQ） thin films were determined in the frequency range of 0.5 k Hz–5 mHz and the temperature range of 290–443 K. The AC electrical conduction of both compounds in thin film.form is governed by the correlated barrier hopping（CBH） mechanism. Some parameters such as the barrier height, the maximum barrier height, the density of charges, and the hopping distance were determined as functions of temperature and frequency. The phenoxyphenyl group has a greater influence on those parameters than the chlorophenyl group. The AC activation energies were determined at different frequencies and temperatures. The dielectric behaviors of Ph-HPQ and Ch-HPQ were investigated using the impedance spectroscopy technique. The impedance data are presented in Nyquist diagrams for different temperatures. The Ch-HPQ films have higher impedance than the Ph-HPQ films. The real dielectric constant and dielectric loss show a remarkable dependence on the frequency and temperature. The Ph-HPQ has higher dielectric constants than the Ch-HPQ.

关键词： thin films quinoline derivatives dielectrical properties correlated barrier hopping

OPTImIZATION Of THE SYNTHESIS Of ACRYLAmIDE HYDROGEL BY γ-RAY IRRADIATION

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Chinese Journal of Polymer Science 2004年第3期22卷 253-258页

作者： m.A. Chowdhury m.m. Alam m.f. mina f. Akhtar S.E. Kabir Department of Chemistry Faculty of Science Jahangir Nagar University Dhaka BangladeshNRCD INST AERE GPO Box-3787 Dhaka Bangladesh NRCD INST AERE GPO Box-3787 Dhaka Bangladesh NRCD INST AERE GPO Box-3787 Dhaka Bangladesh Department of Chemistry Faculty of Science Jahangir Nagar University Dhaka Bangladesh

Hydrogels have been synthesized from 10%, 20%, 30%, 40%, 50% and 60% aqueous solutions of acrylamide monomer by gamma radiation employing doses in the range of 0.2-30 kGy from a Co-60 source. The effect of solution concentration, γ-ray dose, pH and time was studied in order to observe the optimizing conditions in the characterization of hydrogels. Gel fraction increases with dose for all concentrations indicating hundred-percentage conversion of gel at doses 5 kGy for homogenous solutions in the range of 20%-50% concentration. On the other hand, 10% solution provides conversion less than 86% even at 30 kGy, whereas 60% monomer makes an inhomogeneous solution which stile gives about 100% gel fraction. Swelling of hydrogels under water with respect to time varies with both the doses and concentrations due to the change of crosslinking density in the gels. The maximum volume change of hydrogels during swelling and water desorption mainly occurs within 24 h. Swelling is also enhanced with the rise of pH due to change of ionic content of the solvent. Considering the amount of gel fraction and the properties of hydrogel, the samples prepared from 20% solution at 5 kGy show better results. moreover, the effect of bacteria on hydrogel was found to be nil, suggesting a prohibition of growth of microorganism in it.

关键词： Hydrogel Acrylamide γ-radiation Swelling microorganism

瞬态转速分析及其在发动机气缸故障诊断中的应用(英文)

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大连海事大学学报 2002年第B8期28卷 56-60页

作者：白广来孟宪尧 m.f White 大连海事大学自动化研究所辽宁大连116026 marine machinery Inst.Norwegian Univ.of Science&Technology

发动机气缸内的压力和气压产生的扭矩是一个非常重要但运行时很难得到的参数。为此 ,描述了一种通过测量和分析发动机的瞬态转速来监测气缸内的压力和压力扭矩的方法。在发动机模型和测量的瞬态转速信号的基础上 ,经过傅立叶变换和傅立... 详细信息

发动机气缸内的压力和气压产生的扭矩是一个非常重要但运行时很难得到的参数。为此 ,描述了一种通过测量和分析发动机的瞬态转速来监测气缸内的压力和压力扭矩的方法。在发动机模型和测量的瞬态转速信号的基础上 ,经过傅立叶变换和傅立叶逆变换 ,可得出发动机各缸的气压扭矩的波动波形。根据气压扭矩振动波形可监视发动机气缸内的工作状态和对故障气缸做出诊断。

关键词：瞬态转速分析发动机气缸故障诊断船舶轮机设备