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Dopant Occupancy in MgO-Codoped Lithium Niobate Crystals

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Journal of Rare Earths 2006年第z1期24卷 276-280页

作者： He Xiangke Xue Dongfeng State Key Laboratory of Fine chemicals Department of Materials Science and Chemical Engineering School of Chemical Engineering Dalian University of Technology Dalian 116012 China Key Laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of Technology Dalian 116023 China State Key Laboratory of Fine Chemicals Department of Materials Science and Chemical Engineering School of Chemical Engineering Dalian University of Technology Dalian 116012 China Key Laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of Technology Dalian 116023 China

On the basis of the bond valence model, the preferential occupancy of various dopant such as Mn2+, Eu3+, Er3+, Nd3+, Lu3+, Yb3+, In3+, Cr3+, Fe3+ and Ti4+ in the ideal stoichiometric lithium niobate (SLN) crystallographic frame was investigated in a viewpoint of chemical bonds. Theoretical analysis indicates that the dopant occupancy is significantly influenced by the anti-site Nb4+Li. Our work also shows that Mg-like ions (Mg2+, Zn2+, In3+, Sc3+) have a repulsive effect on Nb4+Li ions. When removing Nb4+Li ion by codoping Mg-like ions, the dopant occupancy in the LN crystallographic frame is determined by the natural characteristics of dopant, which is consistent well with the result in the ideal SLN crystals.

关键词： lithium niobate bond valence model codoping dopant occupancy

Electrochemical Studies of Cytochrome c on Electrodes Modified by Single-Wall Carbon Nanotubes

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Chinese Journal of Chemistry 2003年第4期21卷 436-441页

作者：程发良杜珊金葆康 School of Chemistry and chemical engineering Anhui University department of Applied Chemistry Dongguan University of TechnologyDongguanGuangdong 523106 China

Single wall carbon nanotubes (SWNTs) modified gold electrodes were prepared by using two different methods. The electrochemical behavior of cytochrome c on the modified gold electrodes was investigated. The first kind of SWNT modified electrode (noted as SWNT/Au electrode) was prepared by the adsorption of carboxyl terminated SWNTs from DMF dispersion on the gold electrode. The oxidatively processed SWNT tips were covalently modified by coupling with amines (AET) to form amide linkage. Via Au—S chemical bonding, the self assembled monolayer of thiol unctionalized nanotubes on gold surface was fabricated so as to prepare the others SWNT modified electrode (noted as SWNT/AET/Au electrode). It was shown from cyclic voltammetry experiments that cytochrome c exhibited direct electrochemical responses on the both electrodes, but only the current of controlled diffusion existed on the SWNT/Au electrode while both the currents of controlled diffusion and adsorption of cytochrome c occurred on the SWNT/AET/Au electrode. Photoelastic Modulation Infared Reflection Absorption Spectroscopy (PEM IRRAS) and Quartz Crystal Microbalance (QCM) were employed to verify the adsorption of SWNTs on the gold electrodes. The results proved that SWNTs could enhance the direct electron transfer process between the electrodes and redox proteins.

关键词： single wall carbon nanotubes modified gold electrode PEM IRRAS QCM

Synthesis and Characterization of the First Dinuclear Europium(Ⅱ) Complex Supported by Carbon-Bridged Biphenolate Ligand

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Journal of Rare Earths 2006年第3期24卷 264-267页

作者：刘宝姚英明邓明宇张勇沈琪 Key Laboratory of Organic Synthesis of Jiangsu Province Department of Chemistry and Chemical Engineering Suzhou University Suzhou 215123 China

Anhydrous EuCl3 reacted with sodium carbon-bridged biphenolate LNa2[ L = 2,2＇-methylene bis（6-tert-butyl-4- methyl-phenoxo ] in a 1 ： 1 molar ratio in THF in the presence of HMPA （HMPA = hexamethylphosphoric triamide）, then the product formed in situ was reduced by Na-K alloy to generate the divalent carbon-bridged biphenolate europium complex [ LEu （HMPA） 2 ] 2 （THF） 4 （ 1 ） in a good isolated yield. Complex 1 was fully characterized by elemental analysis, NMR and IR spectra, and X-ray structural determination. The crystal data of complex 1 are monoclinic, P2 1/c space group, a=1.6521（3） nm, b=2.8274（3） nm, c=1.2074（2） nm, β=111.723（6）°, V=5.2393（14） nm^3, Z=2, Dc= 1.259 mg·m^-3, μ = 1.304 mm^-1, F（000） = 2092, R = 0.0815, wR = 0. 1723. Complex 1 is a dimer with two Eu - O bridges. The coordination geometry of each europium atom can be best described as a distorted trigonal bipyramid.

关键词： inorganic chemistry carbon-bridged biphenolate lanthanide complex crystal structure rare earths

A study on monoterpenoid-based natural deep eutectic solvents

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Green chemical engineering 2023年第1期4卷 99-114页

作者： Sara Rozas Lorena Zamora Cristina Benito Mert Atilhan Santiago Aparicio department of Chemistry University of BurgosBurgos09001Spain department of chemical and Paper engineering Western Michigan UniversityKalamazooMI49008-5462USA

Herein,the synthesis and characterization methods of natural deep eutectic solvents based on monoterpenoids have been *** viscous fluids with suitable physicochemical properties are *** materials are non-toxic,biodegradable,and ***,they can be used to develop sustainable solvents for various processes and can find their applications in various fields.A theoretical study based on quantum chemistry and classical molecular dynamics is used for the nanoscopic characterization of structure,dynamics,and hydrogen *** reported results help analyze the properties of this new family of *** required information for developing structure–property relationships for proper solvent design to form a sustainable chemistry framework is obtained.

关键词： Natural deep eutectic solvents Terpenes DFT MD COSMO-RS CO_(2)solubility

Reversible Chain Transfer Catalyzed Polymerization with Alkyl Iodides Generated from Alkyl Bromides by in Situ Halogen Exchange

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Chinese Journal of Polymer Science 2021年第9期39卷 1161-1168页

作者： Dan-Ni Gao Yu-Lai Zhao Jing-Yu Cai Lin-Xi Hou Long-Qiang Xiao department of Materials-Oriented chemical engineering School of Chemical EngineeringFuzhou UniversityFuzhou 350116China Qingyuan Innovation Laboratory Quanzhou 362801China Fujian Key Laboratory of Advanced Manufacturing Technology of Specialty chemicals Fuzhou UniversityFuzhou 350116China

Reversible chain transfer catalyzed polymerization(RTCP)is a practical and efficient process for the precise synthesis of polymers with special architecture by using simple phenols(2,4,6-trimethylphenol,TMP)or hydrocarbons(xanthene,XT)as efficient ***,alkyl iodide(R-1),which was gen erated from in situ bromine-iodine transformation of alkyl bromide(R-Br)with sodium iodide(Nal),was served as initiator to mediate RTCP with TMP or *** and other functional methacrylates,including GMA,DEAM,DMAEMA and BzMA,were successfully initiated by combining orga no catalysts and azo in itiators to yield polymers with low-polydispersity(M_(w)/M_(n)=1.1-1.5)and ideal mono mer conversions(50%-90%)at moderate *** over,3-armstar polymers were also obtained by this *** high chain-end fidelity of the obtained poly(methyl methacrylate)with iodine as chain-end group(PMMA-I)was confirmed by chain-extension *** en vironme ntally frie ndly initiators and orga no catalysts exhibit powerful polymerization properties toward RTCP,providing a sign ificant method to synthesize functional polymers.

关键词： Reversible chain transfer catalyzed polymerization Organocatalyst Halogen exchange

Modeling of microreactor for syngas production by catalytic partial oxidation of methane

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Journal of Natural Gas Chemistry 2010年第6期19卷 660-668页

作者： Akbar Zamaniyan Alireza Behroozsarand Hamid Mehdizadeh Hussein Ali Ghadirian department of Natural Gas Conversion Gas Research DivisionResearch Institute of Petroleum Industry (RIPI)Tehran 14665-1998Iran department of chemical engineering Islamic Azad UniversityIlkhchi BranchIlkhchiTabriz 53581-1148Iran department of chemical engineering NTNUTrondheimNO-7491Norway

Fixed-bed reactors for the catalytic partial oxidation of methane （CPOM） to produce synthesis gas still pose hot spots *** is a good alternative reactor proposed to resolve these *** this paper,synthesis gas （hydrogen and carbon monoxide） production was investigated by a two-dimensional numerical model of single *** fluid dynamic （CFD） modeling with detailed chemistry was conducted to understand the CPOM on platinum （Pt） *** inlet velocity,microchannel pressure,and fuel to air ratio （F/A） are selected as the effective parameters on microchannel *** results show that Reynolds number has considerable effect on methane conversion,hydrogen to carbon monoxide ratio （H2/CO）,and product *** gas inlet velocity causes all the above parameters to *** is noted that increasing microchannel pressure and decreasing the ratio of fuel to air cause the decrease of the H2/CO ratio.

关键词： synthesis gas microchannel catalytic partial oxidation of methane reynolds number

chemical composition,antioxidant and antibacterial activities of essential oil and methanol extract of Artemisia vulgaris and Gaultheria fragrantissima collected from Nepal

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Asian Pacific Journal of Tropical Medicine 2017年第10期10卷 952-959页

作者： Bishnu Prasad Pandey Rupak Thapa Anil Upreti department of chemical Science and engineering Kathmandu UniversityDhulikhelKavreNepal department of Biotechnology Kathmandu UniversityDhulikhelKavreNepal

Objective: To identify the chemical constituents and biological activities of essential oil and crude methanol extract of Artemisia vulgaris(***) and Gaultheria fragrantissima(***).Methods: Phytochemical screening, total phenolic and flavonoid content, antibacterial activities, anti-oxidant assay of the crude extract were carried out to identify the biological activities and phytonutrients present in the ***, the chemical constituents present in the essential oil and crude methanol extract were analyzed using gas chromatography mass spectroscopy and high performance liquid chromatography(HPLC) ***: Gas chromatography mass spectroscopy analysis of essential oil from the aerial part of *** revealed 24 different compounds in ***(11.29%), b-thujone(19.19%), chrysanthenone(4.48%), camphor(11.89%), borneol(4.44%) and germacrene D(8.42%) were the major ***, leaves of *** contained methyl salicylate(95%) and asarone(4.64%).Furthermore, methanol extract of leaves of *** and *** were found rich in the total flavonoids and phenolic *** analysis of the methanol extract of leaves *** revealed the presence of morin and luteolin, whereas rutin was found as a major flavonoids compound in the leaves of ***, methanol extract of the *** and *** showed the highest antioxidant and antibacterial properties compared to the essential ***: The HPLC analysis of the methanol extract of *** shows the presence of luteolin and morin, whereas *** reveals the presence of rutin and a glycosylated *** reveal that *** oil is the rich source of monoterpene and sesquiterpene ***, *** and *** are the rich source of the phenolic and flavonoids compounds and show good antioxidant and antibacterial activity.

关键词： Artemisia vulgaris Gaultheria fragrantissima Flavonoids Antioxidant HPLC Gas chromatography mass spectroscopy

First-principles study on mechanical properties of LaMg_3 and LaCuMg_2

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Journal of Central South university 2014年第6期21卷 2136-2142页

作者：王明辉潘荣凯李鹏博卞楠唐壁玉彭立明丁文江 School of Chemistry and chemical engineering Guangxi University department of Physics Xiangtan university Light Alloy Net Forming National engineering Research Center School of Materials Science and EngineeringShanghai Jiaotong University

Abstract： With the substitution of part Mg in LaMg3 by Cu, the elastic constants CH and C12 increase while C44 decreases, implying an enhanced Poisson effect and smaller resistance to 〈001〉（100） shear. Furthermore, the bulk modulus B increases, while the shear modulus G, elastic modulus E and anisotropie ratio A are reduced. The calculated Debye temperature of LaCuMg2 is lower, implying the weaker interaction between atoms in LaCuMg2. Then, the stress-strain curves in entire range and the ideal strength at critical strain are studied. The present results show that the lowest ideal tensile strength for LaMg3 and LaCuMg2 is in the 〈100〉 direction. The ideal shear strength on the 〈 1 ^-1 0〉（110） slip system of LaMg3 is greater than LaCuMg2. The density of states and charge density distribution are further studied to understand the inherent mechanism of the mechanical properties.

关键词： first-principle calculations elastic constant ideal strength mechanical properties electronic structure

Surface Analysis of ZIRLO Alloy Implanted with Carbon

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Journal of Rare Earths 2005年第S1期23卷 373-377页

作者：彭德全白新德潘峰孙辉陈宝山 department of Materials Science and engineering Tsinghua University Beijing 100084 China Jianzhong chemical Cooperation Yibin 644000 China

ZIRLO alloy specimens were implanted with carbon ions with fluence range from 1×10 16 to 1×10 18ions·cm -2, using a MEVVA source at an extraction voltage of 40 kV at maximum temperature of 380 ℃. The surfaces of the implanted samples were then analyzed and the TRIM 96 computer code was used to simulate the depth distribution of carbon. The valences of elements in the implanted surface of ZIRLO alloy were analyzed by X-ray photoemission spectroscopy (XPS); and then the depth distributions of the elements on the surface of the samples were obtained by Auger electron spectroscopy (AES). Scanning electron microscopy (SEM) was used to examine the micro-morphology of implanted samples. Glancing angle X-ray diffraction (GAXRD) at 0.30 incident angles was employed to examine the phase transformations of implanted samples. It shows that the as-received ZIRLO alloy is mainly composed of hexagonal alpha zirconium, as for implanted samples, there appeared hexagonal zirconia (H-ZrO_ 0.35) and sigma zirconium carbide (δ-Zr_3C_2), and the δ-Zr_3C_2 increased when increasing the fluence. When the fluence reached 1×10 18 ions·cm -2, the concentration of δ-Zr_3C_2 is the maximum in all the samples. The micro-morphology of implanted samples are similar, there are many pits with diameters ranging from 1 to 3 μm on the implanted surfaces.

关键词： ZIRLO alloy carbon ion implantation X-ray photoemission spectroscopy (XPS) auger electron spectroscopy (AES) glancing angle X-ray diffraction (GAXRD)