Synthesis and electrochemical performance of Li_3V_2(PO_4)_3 by optimized sol-gel synthesis routine

Li3V2(PO4)3 samples were synthesized by sol-gel route and high temperature solid-state reaction.The influence of Li3V2(PO4)3 as cathode materials for lithium-ion batteries on electrochemical performances was investigated.The structure of Li3V2(PO4)3 as cathode materials for lithium-ion batteries and morphology of Li3V2(PO4)3 were characterized by X-ray diffractometry(XRD) and scanning electron microscopy(SEM).Electrochemical performances were characterized by charge/discharge and AC impedance measurements.Li3V2(PO4)3 with smaller grain size shows better performances in terms of the discharge capacity and cycle stability.The improved electrochemical properties of Li3V2(PO4)3 are attributed to the refined grains and enhanced electrical conductivity.AC impedance measurements also show that the Li3V2(PO4)3 synthesized by sol-gel route exhibits significantly decreased charge-transfer resistance and shortened migration distance of lithium ions.

Hydrothermal Synthesis, Crystal Structure, Spectrum and Electrochemical Analysis of the Copper(Ⅱ) Coordination Polymer

The three-dimensional framework copper(Ⅱ) coordination polymer with basic copper carbonate and 3-(pyridin-2-yl)-1,2,4-triazole has been hydrothermally synthesized. It crystallizes in monoclinic space group P21/c, with a = 1.20860(3), b = 1.29581(2), c = 1.67863(3) nm, β = 116.0280(2)°, C21H12Cu3N12, Mr = 623.05, V = 2.36230(9) nm3, Dc = 1.752 g/cm3, Z = 4, F(000) = 1236, GOOF = 1.037, the final R = 0.0408 and wR = 0.1141. Every unit cell contains three copper atoms and three 3-(pyridin-2-yl)-1,2,4-triazole ligands. Every central Cu(Ⅱ) ion is coordinated by four nitrogen atoms of the 3-(pyridin-2-yl)-1,2,4-triazole ligands, forming a distorted tetrahedron. The title complex exhibits an intense photoluminescence at room temperature with the maximum emission at 392 nm. The cyclic voltametric behavior of the complex shows that the electron transfer in electrolysis reaction is irreversible.

Synthesis and Crystal Structure of Bridging Complex [Cu_2(bipy)_2·OAc·Cl·OH]·TsTausH·3H_2O

The title complex [Cu2(bipy)2OAcClOH]TsTausH3H2O(C31H37Cl- Cu2N5O11S2) has been synthesized by the reaction of 2,2?bipyridine(bipy), N-P-tolysulfony taurine (TsTausH) and copper acetate in water-ethanol solution, and its crystal structure was determined by X-ray diffraction method. The crystal belongs to triclinic, space group P with a = 0.74485(14), b = 1.6094(3), c = 1.7472(3) nm, a = 114.662(4), b = 99.997(4), g = 93.218(4), V = 1.8551(6) nm3, Mr = 882.31, Z = 2, Dc = 1.580 g/cm3, m = 1.395 mm-1 and F(000) = 906. The complex is a binuclear copper compound, and the two copper ions nearly have the same coordination environment. There exists MM bond in the complex. The distance of Cu(1)Cu(2) is 0.29747(7) nm. The two ions form two distorted octahedral geometries.

QSPR Studies on lgK_(ow) and lgK_(oc) of Fluorobenzenes and Property Parameters Based on HF and DFT Calculations

Quantum chemistry parameters of 22 fluorobenzenes were computed at six levels using Hartree-Fock and DFT methods. Based on the experimental data of n-octanol/water partition coefficient (lgKow), a three-parameter (dipole moments (μ), zero point energy (ZPE) and free energy (G°)) quantitative correlation equation that can predict lgKow was developed using structural and thermodynamic parameters as theoretical descriptors. Similarly, based on experimental data of soil organic carbon sorption coefficient (lgKoc), the other three-parameter (the most negative atomic net charge of molecule (q-), dipole moments (μ) and molecular volume (Vi)) quantitative correlation equation that can predict lgKoc was given. Quantitative correlation equations based on B3LYP/6- 311G** calculation were validated by VIF (variance inflation factors) and t-test and used to predict lgKow and lgKoc of a series of compounds. The result showed that the correlation and prediction ability of lgKoc equations based on three levels of HF/STO-3G, B3LYP/6-31G* and B3LYP/6- 311G** are all more advantageous than those based on AM1.

Synthesis and Structure of anti-Configuration Complex [Cu(tssb)_2]·2[(H_3O)Cl]·4H_2O

The title complex [Cu(tssb)2]2[(H3O)Cl]4H2O (C18H34Cl2CuN2O14S2) (tssb = tau- rine salicylaldehyde Schiff base) has been synthesized by the reaction of taurine salicylaldehyde Schiff base (tssb) and copper acetate in water-ethanol. Its single-crystal structure was determined by X-ray diffraction method. The crystal structure belongs to triclinic, space group P1 with a = 0.7407(1), b = 1.3329(3), c = 1.5736(3) nm, ?= 103.800(4), ?= 95.030(4), ?= 104.416(4)? Mr = 701.06, V = 1.4433(5) nm3, Z = 2, Dc = 1.613 g/cm3, = 1.153 mm-1 and F(000) = 726. The compound is an infinitely expanding three-dimensional network connected with hydrogen bonds. The Cu(Ⅱ) atom is coordinated by two nitrogen and two oxygen atoms to form a distorted planar coordination compound which adopts anti-configuration because two sulfonic acid groups are posi- tioned diagonally on a plane.

Synthesis, Crystal Structure and Spectrum Properties of Trinuclear Manganese Coordination Compound Mn_3(2,2'-bipy)_2(3,5-DMBA)_6

A novel complex Mn3(2,2'-bipy)2(3,5-DMBA)6 with 3,5-dimethylbenzoic acid (3,5-DMBA) and 2,2'-bipyridine (2,2'-bipy) has been synthesized by means of a solvent method. It crystallizes in the monoclinic space group C2/c with a=3.1118(6), b=1.1754(2), c=2.0887(4) nm, β=118.50(3)o, V=6.714(2) nm3 , Dc=1.384 g/cm3 , Z=8, F(000)=2912, the final GOOF=1.078, R=0.0691 and wR=0.1455. The crystal structure shows that the three coordinated manganese(Ⅱ) ions lie in a line with the middle one as the symmetric center. The distance between the central manganese(Ⅱ) and the symmetric one is 0.3549 nm. There exist two coordination modes for the three manganese (Ⅱ) ions: the symmetric manganese(Ⅱ) ions are coordinated with three oxygen atoms and two nitrogen atoms from three 3,5-DMBA molecules and one 2,2'-bipy molecule, respectively, forming a distorted square-pyramidal coordination geometry; the middle manganese(Ⅱ) ion is coordinated with six oxygen atoms from six 3,5-DMBA molecules, generating a distorted octahedral coordination geometry. Spectrum properties of the complex were also studied.

Experimental and QSPR Studies on n-Octanol/water Partition Coefficient (lgK_(ow)) of Substituted Aniline

The n-octanol/water partition coefficients (lgKow) of 18 substituted anilines were determined at 25 ℃ by shake-flask method. The geometrical optimization of substituted anilines has been performed at B3LYP/6-311G** level with Gaussian98 program, and the molecular surface areas of substituted anilines were calculated using ChemOffice 2004 program. The calculated structural parameters of substituted anilines were used as theoretical descriptors and the two-parameter (molecular surface area (MA) and the energy of the highest occupied molecular orbital (EHOMO)) quantitative structure-property relationship (QSPR) model of lgKow for substituted aniline with molecular structural parameters was developed by multi-linear regression method. The regression coefficient square (r2) is 0.990 and the standard deviation SE 0.109. The model was validated by variance inflation factors (VIF) and t-test, and the results show that there exists small self-correlation between variables of the model with perfect stability. The model gives results in good qualitative agreement with experimental data. At last, the model was applied to predict lgKow values of five substituted anilines whose lgKow values have not been determined experimentally.

Synthesis,Structure and Electric Property of a 3D Supramolecular Co^ⅡCoordination Complex

The title compound, [Co(C_(16)H_(10)N_2S_4)_2(H_2O)_4](C_(14)H_9N_2O_4)2(1,C_(16)H_(10)N_2S_4=4-pyridine-tetrathiafulvalene-4-pyridine and C14 H9 N2 O4 = 4-(4-carboxyphenyl)diazenyl)benzoate),has been successfully synthesized under hydrothermal conditions. The structure was determined by elemental analyses and single-crystal X-ray diffraction analysis. Moreover, the conductivity property of compound 1 was investigated. Compound 1 crystallizes in triclinic system, space group P1 with a = 6.4006(3), b = 7.1818(4), c = 33.0932(14) ?, α = 89.261(4), β = 86.530(3), γ = 66.642(4)°, V =1393.90(12) ?3, Z = 1, C60 H46 N8 O12 S8 Co, M3 r = 1386.46, Dc = 1.652 g/cm, μ = 0.684 mm-1 and F(000) = 713. The final R = 0.0411 and wR = 0.0810 for 3936 observed reflections with I > 2σ(I).Compound 1 contains one-half of the complex cation with the CoI I ion located on an inversion center,and one 4-(4-carboxyphenyl)diazenyl)benzoate counter anion. The Co atom has a N2 O4 octahedral coordination. Complex 1 forms a three-dimensional supramolecular network and a semiconducting behavior is observed with srt= 0.04 S·cm-1.

A novel, simple and sensitive resonance scattering spectral method for the determination of chlorite in water by means of rhodamine B

A new resonance scattering method was proposed for the determination of chlorite, basing on the resonance scattering effect of rhodamine dye. In HCl-sodium acetate buffer solution, chlorite oxidizes I- into I2 and the reaction of I2 and excess I- results in I3-. It is respectively combined with rhodamine dyes, including rhodamine B (RhB), butyl rhodamine B (b-RhB), rhodamine G (RhG) and rhodamine S (RhS), to form association complex particles, which exhibit stronger resonance scattering (RS) effect at 400 nm. The chlorite concentration of ClO2- in the range of 0.00726—0.218 ?滋g/ml, 0.0102—0.292 ?滋g/ml, 0.00726—0.145 ?滋g/ml and 0.0290—0.174 ?滋g/ml is respectively linear to the RS intensity of association complex particle systems at 400 nm for the RhB, b-RhB, RhG and RhS. The detection limits of the four systems were respectively 0.00436, 0.00652, 0.00580 and 0.01450 ?滋g/ml ClO2-. In the four systems, the RhB system possesses good stability and high sensitivity. It has been applied to the analysis of chlorite in wastewater with satisfactory results.

Design and Experiment of the High Speed Wire Drawing with Ultrasound

The previous experiments of wire drawing with ultrasonic vibration were mostly carried out on self-made machine or drawing test machine and the drawing speed didn't conform to practical production. In order to promote the practical application of the technology,the ultrasonic vibration system was designed and manufactured by using the classical dynamics method. The dynamic characteristic of the ultrasonic vibration system was analyzed. The performance parameters of the system were measured on the resistance analyzer. The oxygen-free brass wire drawing with ultrasonic vibration at the approximate speed of practice was carried out on the LH-200/17 drawing machine. By comparing the wire drawing through ultrasonic vibration and the conventional wire drawing,the experimental results show that the drawing process with ultrasound was steady at the high drawing speed of 1 126 mm/s,while the broken wire often occurs at the speed of 980 mm/s during the conventional wire drawing; the ultrasonic vibration reduced the drawing force by 7 %; and the ultrasound also reduced the uneven deformation of the wire and greatly improved the surface quality of the wire. The research results provide theoretical and experimental support for the practice and application of the wire drawing by ultrasonic vibration.

Synthesis, Structure and Aggregationinduced Emission Characteristics of Two Diaryquioxaline Derivatives

Two new diaryquioxaline derivatives, C21H10N2S3Br2 (1) and C21H10Br2N2OS2(2), have been successfully synthesized. These two compounds have been determined by single-crystal X-ray diffraction analyses. Compound 1 crystallizes in monoclinic system, space group P21/n with a = 12.7896(3), b = 6.0613(2), c = 26.1153(7) A,β= 94.1810(10)°, V = 2018.(97) A^3, Z = 4, C21H10N2S3Br2, Mr = 546.32, Dc = 1.797 g/cm^3 and F(000)= 1072. The final R = 0.0343 and wR = 0.785 for 3585 observed reflections with I> 2σ(I). Compound 2 crystallizes in monoclinic system, space group P2x/n with a = 7.8638(4), b = 14.3447(7), c = 17.8936(8) A, β = 96.6980(10)°, V = 2004.69(17) A3, Z = 4, C21H10Br2N2OS2, Mr = 530.25, Dc = 1.757 g/cm^3 and F(000)= 1040. The final R = 0.0988 and wR = 0.1108 for 4613 observed reflections with I > 2σ(I). By combination of diarylquinoxaline core and a 1,3-dithiole-2-thione unit, compound 1 is used as "turn on" chemosensors for Hg^2+by making use of the aggregation-induced emission (AIE) feature of diarylquinoxaline core and the specific reaction of 1,3-dithiole-2-thione with Hg^2+.

Microstructure of Carbon Fiber and Carbon Reinforced Plastic

This study is the investigation of the microstructure of different types of carbon fiber. They were compared with the carbonized and graphitized fibers. Results of structural researches have been presented. It was found that the damage varies from different pollution and the damage of the monofibers. The effect of the pollution of the monofiber was determined.

Comparative DFT Study of [Mg(CHZ)_3](ClO_4)_2 and [Mg(CHZ)_3](NO_3)_2(CHZ=Carbohydrazide)

The molecular geometry,electronic structure,thermochemistry and infrared spectra of [Mg(CHZ)3](ClO4)2 and [Mg(CHZ)3](NO3)2 were comparatively studied using the Heyd-Scuseria-Ernzerhof(HSE) screened hybrid density functional with 6-31G** basis set.The experimental results show that the complexes have six-coordinated octahedron feature,and the metal-ligand interactions are predominantly ionic in nature.The calculated heats of formation predict that [Mg(CHZ)3](NO3)2 is more stable than [Mg(CHZ)3](ClO4)2.Detailed NBO analyses indicate that the ligand-anion interaction plays an important role in the stability for these two energetic complexes.Moreover,the stretching vibration frequencies of N-H bonds shift to lower wave number compared to the free CHZ ligand,which are caused by the delocalizations from N-H bond orbital to lone-pair electron antibond orbital of magnesium.

Thermal behavior and Rheological Properties of PANI-DBSA/PAN Blends

Conducting blends of polyacrylonitrile (PAN) copolymer and dodecylbenzene sulfonic acid doped polyaniline (PANI-DBSA) were prepared by solution blending of the two components. By means of various characterization methods including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and cone-plate rheometry, the effects of PANI-DBSA content on the thermal behavior, morphological and rheological properties of the blends were investigated. A single and composition-dependent Tg was found for each of all blends and the thermal stability of PANI-DBSA/PAN was superior to that of both pure Co-PAN and PANI- DBSA. Rheological results show that the apparent viscosity of blend solution decreased at low PANI- DBSA content (2.5 wt%) while increased at high PANI-DBSA content (7.5wt%-10 wt%). Moreover, the shear-thinning appeared more distinctly with the incorporation of PANI-DBSA into the blend solutions especially at a high shear rate.

A new type of photon-added squeezed coherent state and its statistical properties

We construct a new type of photon-added squeezed coherent state generated by repeatedly operating the bosonic creation operator on a new type of squeezed coherent state [Fan H Y and Xiao M 1996 Phys. Lett. A 220 81]. We find that its normalization factor is related to single-variable Hermite polynomials. Furthermore, we investigate its statistical properties, such as Mandel's Q parameter, photon-number distribution, and Wigner function. The nonclassicality is displayed in terms of the intense oscillation of photon-number distribution and the negativity of the Wigner function.

Preparation of Organic Montmorillonite and Mechanical Properties of Montmorillonite/Unsaturated Polyester Composites

The synthesis process of organic montmorillonite was designed and some kinds of montmorillonite/unsaturated polyester composites using different interlayer spacing montmorillonite were prepared. The interlayer spacing of montmorillonite was investigated by XRD and was increased to 3.98nm. The relationship between the four influential factors and the interlayer spacing were regressively analyzed and the mathematical model was established, and the result shows when the content of organic reagent was less than 70%, the relationship between the interlayer spacing and the content was linear as follows: interlayer spacing=1.771+2.828×concentration, the effect of the other factors was not significant. Additionally, the testing of mechanical properties of the composites showed the impact strength was improved by 217%, and the bending strength was improved by 355%, when using the montmorillonite(MMT) of the largest interlayer spacing (3.98 nm).The result of ESEM shows the interface is bonded well when the composite specimen contains the 3.98 nm MMT.

Analysis of Valence Electron Structure of RE in Solid Solution in Medium and Low Carbon Steel

According to EET theory, the valence electron structures of RE in the solid solution of austenite, pearlite and martensite were calculated. The influence of RE in solid solution on phase transformation of pearlite and recrystallization of martensite was explained by the valence electron structure data of phases. Calculating results indicate that C element is favorite to enhance the number of RE in the solid solution. RE in the solute solution shortens the incubation period of proeutectoid ferrite, increases its quantity and carbon content, decreases the quantity of pearlite and thickness of its lamellas and lamellar spacing, then the strength and hardness of pearlite are improved and granular pearlite can be obtained. RE dissolved in martensite intensifies martensite, enhances tempering stability of martensite, increases its recrystallization temperature and prolongs the holding time needed during tempering.

Estimation of n-Octanol/water Partition Coeffi-cients(lgK_(ow)) and the Aqueous Solubility(-lg_(Sw)) of all PCDF Congeners by Density Functional Theory

Optimized calculation of dibenzofuran (DF) and 135 polychlorinated diben- zofurans (PCDFs ) was carried out at the B3LYP/6-31G* level in GAUSSIAN 98 program. Based on the theoretical linear solvation energy relationship (TLSER) model, the obtained structural parameters were taken as theoretical descriptors to establish the novel quantitative structure- property relationship (QSPR) model for predicting n-octanol/water partition coefficients (lgKow) of PCDFs. The new model of lgKow achieved in this work contains three variables: energy of the highest occupied molecular orbital (EHOMO), the most negative atomic partial charge (q-) and average molecular polarizability (α), of which R2 = 0.9011 and SD = 0.17 with larger t values. In addition, the variation inflation factors (VIF) of variables in the present model are all less than 5.5, suggesting high accuracy of the lgKow model. And the results of cross-validation test (q2 = 0.8688) and method validation also show this model exhibits optimum stability and better predictive power than semi-empirical method. At the same time, it is found that the aqueous solubility (-lgSw) has high relative correlation with constant volume molar heat capacity (CV0), of which R2 = 0.9777 and SD = 0.22. Moreover, lgKow and -lgSw values of all PCDF congeners were predicted respectively.

Preparation and mechanical properties of TLCP/ UP / GF in-situ hybrid composites

One kind of novel reactive thermotropic liquid crystalline polymer-methacryloyl copolymer (LCMC) containing polyester mesogenic units was synthesized. Its structure, morphology and properties were investigated systemically by Ubbelohde viscometer, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffractometry (WAXD) and polarizing optical microscopy (POM). The results indicate that it is one kind of nematic thermotropic liquid crystal polymer (TLCP). The impact strength, bending strength and the morphologies of impact fracture surface of LCMC, unsaturated polyester (UP) and glass fiber (GF) in-situ hybrid composites were studied by Izod impact tester, universal testing machine and scanning electron microscopy (SEM), respectively. The results show that the impact and bending strength of composites containing LCMC are improved, especially the composites containing 5% LCMC increases most obviously. These results with SEM results reveal that LCMC plays an important role in the improvement of interfacial adhesive between matrix and fiber.