Helioal Structure and Optical Activity of Two New Derivatives of R(+)-1,1'-Binaphthyl-2,2'-diol

Correlation between the belieal structure and optical activity of two derivatives of R(+)- 1, 1'-binaphthyl-2,2'-diol was derived from a study of their optical rotations, CD curves and Xray crystal structures.

Crystal Structure, Energy Band and Optical Properties of Phosphate In(PO_3)_3

The crystal of the title compound （InP3O9, Mr = 351.73） has been prepared and structurally determined by X-ray single-crystal diffraction. It crystallizes in the monoclinic system, space group Cc with a = 13.545（6）, b = 19.603（7）, c = 9.672（4）A, β= 127.196（4）°, V= 2045.6（14） ,A^3 and Z = 12. The compound, with a three-fold superstructure, has two kinds of infinite chains of PO4 tetrahedra along the c axis. The absorption and luminescence spectra of In（PO3）3 powder have been measured. The calculated results of crystal energy band structure by DFT indicate that the solid state is kind of insulator. What is more, the bonding and optical properties were also investigated with the CASTEP code.

Study on Band Structure of YbB_6 and Analysis of Its Optical Conductivity Spectrum

The electronic structure of YbB6 crystal was studied by means of density functional （GGA ＋ U） method. The calculations were performed by FLAPW method. The high accurate band structure was achieved. The correlation between the feature of the band structure and the Yb-B6 bonding in YbB6 was analyzed. On this basis, some optical constants of YbB6 such as reflectivity, dielectric function, optical conductivity, and energy-loss function were calculated. The results are in good agreement with the experiments. The real part of the optical conductivity spectrum and the energy-loss function spectrum were analyzed in detail. The assignments of the spectra were carried out to correlate the spectral peaks with the interband electronic transitions, which justify the reasonable part of previous empirical assignments and renew the missed or incorrect ones.

Optical Properties, Electronic Energy Level Structure and Electroluminescent Characteristics of Salicylaldehyde Anil Zinc

A new electroluminescent material, salicylaldehyde anil zinc （SAZ） was synthesized, which can form high quality, thermal stability, nano-scale amorphous films by vacuum evaporation. Its structure, thermal stability were characterized by infrared （IR） spectra, differential thermal analysis-thermogravimetry （DTA-TG） analysis, respectively. The optical properties of SAZ were investigated by UV absorption spectra, Photoluminescence （PL） excitation and emission spectra. The highest occupied molecular orbits （HOMO）, lowest unoccupied molecular orbits （LUMO） and optical band gap were evaluated by cyclic voltammetry curve and optical absorption band edge. The electroluminescent devices using SAZ as the emissive layer emit green light with a peak wavelength at 509 nm and a brightness of about 3.1 cd/m^2.

Studies on the Relationship between the Helical Structure and Optical Activity of Some Chiral Cyclic Esters Ⅱ

A method for the analysis of the relationship between the helical structure and optical activity was proposed by the study of the conformations and X-ray diffraction structures of some cyclic esters prepared by esterification of L-(-)-2.3-O-methylidene threitol and L-(+)-2,3-O-isopropplidene threitol with alkanedioyl dichlorides and o-,m-,and p-phthaloyl dichlorides.

Effect of initial crystallization temperature and surface diffusion on formation of GaAs multiple concentric nanoring structures by droplet epitaxy

GaAs multiple concentric nano-ring structures(CNRs)are prepared with multistep crystallization procedures by droplets epitaxy on GaAs(001)to explore the influence of different initial crystallization temperatures on CNRs morphology.Atomic force microscope(AFM)images show that GaAs nanostructures are more likely to form elliptical rings due to diffusion anisotropy.Meanwhile,with the increase of initial crystallization temperature,the inner ring height and density of CNRs are increased,and outer rings are harder to form.In addition,the mechanism of formation of CNRs is discussed by classical nucleation theory and diffusion theory.The method can be used to calculate the diffusion activation energy of gallium atoms(0.7±0.1 eV)on the GaAs(001)surface conveniently.

Analyses of temperature-dependent interface states,series resistances,and AC electrical conductivities of Al/p Si and Al/Bi_4Ti_3O_(12)/p Si structures by using the admittance spectroscopy method

In this study, Al/p-Si and Al/Bi4Ti3O12/p-Si structures are fabricated and their interface states （Nss）, the values of series resistance （Rs）, and AC electrical conductivity （σac） are obtained each as a function of temperature using admit- tance spectroscopy method which includes capacitance-voltage （C-V） and conductance-voltage （G-V） measurements. In addition, the effect of interfacial Bi4Ti3012 （BTO） layer on the performance of the structure is investigated. The voltage- dependent profiles of Nss and Rs are obtained from the high-low frequency capacitance method and the Nicollian method, respectively. Experimental results show that Nss and Rs, as strong functions of temperature and applied bias voltage, each exhibit a peak, whose position shifts towards the reverse bias region, in the depletion region. Such a peak behavior is attributed to the particular distribution of Nss and the reordering and restructuring of Nss under the effect of temperature. The values of activation energy （Ea）, obtained from the slope of the Arrhenius plot, of both structures are obtained to be bias voltage-independent, and the Ea of the metal-ferroelectric-semiconductor （MFS） structure is found to be half that of the metal-semiconductor （MS） structure. Furthermore, other main electrical parameters, such as carrier concentration of acceptor atoms （NA）, built-in potential （Vbi）, Fermi energy （EF）, image force barrier lowering （△φb）, and barrier height （φb）, are extracted using reverse bias C 2-V characteristics as a function of temperature.

Crystal Structure and Thermal Decomposition Kinetics of 3-Nitro-4-diazo-5-oxygenpyrazole

A novel compound 3-nitro-4-diazo-5-oxypyrazole was synthesized by the nitration of 4-amino-3,5-dinitropyrazole using nitrification agents of fuming nitric acid and trifluoroacetic anhydride. The compound was purified by column chromatography and characterized by IR, NMR, MS and elemental analysis. Two different single crystals obtained by culturing with ethyl acetate as a solvent were measured by X-ray single-crystal diffractometer. The molecular weight of C3HN5O3 is 155.09 and the two crystals belong to monoclinic system, space groups P21/n and P21/c. For 1： a = 5.5007（2）, b = 9.0691（4）, c = 11.4158（4） A, β = 92.710°, V = 568.85 A3, Z = 4, Dc = 1.811 g/cm3, μ = 0.162 mm-1, F（000） = 312 and the final deviation factor is 0.0213. Crystals 1 and 2 have similar unit cell parameters, except that a = 10.1828（12）, b = 5.5925（6）, c = 10.5574（10） A and β = 108.330（4）° in crystal 2. The thermal behavior of the compound was studied by TG-DSC and melting endothermic peak and decomposition exothermic peak are at 425.7 and 534.5 K in DSC curve. The activation energy and pre-exponential factor of the exothermic decomposition reaction of the title compound obtained by Kissinger method and Flynn-Wall-Ozawa method are 50.38 k J/mol, 4.59 × 1022 s^（-1） and 55.89 k J/mol.

Correlation of Quantitative Structure and Inhibition Phytotoxicity for Aromatic Compounds Using Ab Initio Method

29 aromatic compounds were computed at the HF/6-31G^＊ level. Based on linear solvation energy theory firstly, the parameters of molecular structure were taken as theoretical descriptors, and the corresponding linear solvation energy relationship （LSER） （r^2= 0.8993, q^2=0.8559） between the structural parameters and inhibition phytotoxicity to the seed germination rate of cucumis （-lgGC50） was thus obtained. Then the parameters of molecular structure and thermodynamics were taken as theoretical descriptors, and as a result the other corresponding correlation equation （r^2=0.9268, q^2=0.8960） relating to -lgGC50 was achieved. The two equations obtained in this work by HF/6-31G^＊ are both more advantageous than that from AM 1.

Influence of crystal structure on mechanical activation effect

The effect of mechanical treatment on pyrite and molybdenite was studied. After mechanically activated for 40 min under the same condition, the apparent activation energy for leaching reaction of layer-structured molybdenite in HNO 3-H 2SO 4 solution becomes 6.0 kJ/mol lower than that for untreated one; while for isotropic pyrite, this value is 18.3 kJ/mol. Pyrite seems to be more sensitive towards mechanical activation. Resorting to the difference in crystal structure, it is considered that anisotropic molybdenite may obviate violate mechanical action through inter-layer slippage, while isotropic pyrie can not. So the action may damage pyrite crystal and produce large amount of lattice imperfection. Consequently, more mechanical energy is absorbed by pyrite crystal. So it is one-sighted to consider the mechanical activation effect according to only crystal lattice energy. Crystal structure, isotropy or anisotropy, is an important parameter which affects a lot.

Studying the variable energy band structure for energy storage materials in charge/discharge process

So far,a clear understanding about the relationship of variable energy band structure with the corresponding charge-discharge process of energy storage materials is still lacking.Here,using optical spectroscopy(red-green-blue(RGB)value,reflectivity,transmittance,UV-vis,XPS,UPS)to studyα-Co(OH)_(2) electrode working in KOH electrolyte as the research object,we provide direct experimental evidence that:(1)The intercalation of OH-ions will reduce the valence/conduction band(VB and CB)and band gap energy(Eg)values;(2)The deintercalation of OH-ions corresponds with the reversion of VB,CB and E_(g) to the initial values;(3)The color of Co(OH)_(2) electrode also exhibit regular variations in RGB value during the charge-discharge process.

Statistical study of “trunk-like” heavy ion structures in the inner magnetosphere

We present a statistical study of“trunk-like”structures observed in He+and O+in the inner magnetosphere.The main characteristic of these structures is that the energy of the peak flux decreases earthward.Using observations from the Helium Oxygen Proton Electron(HOPE)instrument onboard Van Allen Probe A,we identify the trunks observed from November 2012 to June 2019 and obtain the universal time,L shell,magnetic local time(MLT),and energy information of each trunk’s root and tip.We then investigate the behavior of trunks in terms of their frequency of occurrence,temporal evolution,spatial and energy distribution,and trunk dependence on different geomagnetic indices.We find that(1)the trunks are always located at L=1.5−4.0 and have a preferential location mainly concentrated at MLT=18−24,(2)the sector within MLT=14−16 is a forbidden zone without trunk roots,and(3)the energy of He+ trunks is the largest near dusk and gradually decreases in the counterclockwise direction,whereas the energy of O+ trunks is relatively evenly distributed with MLT and L.The differences between He+ and O+ trunks are probably due to the different charge exchange and Coulomb collision lifetime.The dependence on different geomagnetic indices indicates that the trunk structures occur more frequently during relatively quiet periods.

Establishment of correlation between reaction kinetics and carbon structures in the char gasification process

For a gasification process,the char-CO_(2)gasification is the controlling step worthwhile to be deeply investigated.The article chosen corn stalk(CS),poplar sawdust(PS)and bagasse residue(BR)as the typical waste species derived from agricultural,forestal and industrial sources.The char-CO_(2)gasification behavior,reaction kinetics and carbon structure were studied to reveal the intrinsic factors determining the reaction kinetics.Generally,the carbon conversion and maximum conversion rate were influenced by the feedstocks species and char preparation temperatures,as influenced by ash proportion,potassium content in ash and carbon structure of char.The char-CO_(2)reaction for CS was subject more to the catalytic effect of alkali compositions,while pore structure affected more the gasification reaction for PS char.The isoconversional kinetic analysis indicated that the gasification reaction became stable at carbon conversion of 0.5.Subsequently,sectionalized kinetic parameters were calculated for the initial gasification temperature to the temperature reaching 50%conversion.The result showed that high initial gasification temperature increased the char-CO_(2)gasification barrier to hardly start the reaction but accelerate the reaction rate.The carbon structure analyses further clarified that the reaction activation energy was highly related to the microcrystalline structure of carbon,while the reaction rate was more determined by carbon pore structure.

Relationship between the helical structure and optical activity of some chiral cyclic esters

A homologous series of cyclic esters was used as a model for studying and clarifying the relationship between the helical structure and optical activity.

Optical Properties and Activation Energy of A Novel System of Cdte Nanoparticles Embedded in Phosphate Glass Matrix

We report growth and optical properties of a novel system of CdTe nanoparticls doped P2O5–Na2O–ZnO– Li2O glass matrix. We have investigated the effect of concentration, annealing time and temperature on the band gap and size of the CdTe semiconductor nanoparticles. In addition the effect of adding ZnO to the glass matrix on the growing of the nanoparticles has been investigated. We found that the addition of ZnO to the glass composition is strongly affecting the growth of the nanoparticles. On the other hand, we have calcu-lated the size polydispersity index which showed narrow size distribution for the prepared nanoparticles. Furthermore, we have estimated the activation energy of diffusion for the prepared CdTe nanoparticles which gave the activation energy with low value~ 44 kJ mol-1.

Role of ZnO-CeO_2 Nanostructures as a Photo-catalyst and Chemi-sensor

ZnO-CeO2 nanostructures were synthesized by simple and effcient low temperature method. The structure and morphology of the ZnO-CeO2 nanostructures were characterized by X-ray powder diffraction （XRD） and field emission scanning electron microscopy （FESEM）, which revealed elongated shaped CeO2 nanoparticles with diameters of 40–90 nm distributed on the surface of elongated ZnO nanostructures with diameters of 50–200 nm （edge–centre）. Further the structure of the synthesized ZnO-CeO2 nanostructure was supported by Raman spectra and Fourier transform infrared spectroscopy （FTIR）. UV-vis absorption spectrum was used to confirm the optical properties of the CeO2 doped ZnO nanostructures. Photo-catalytic activity of CeO2 doped ZnO nanostructure was evaluated by degradation of acridine orange and methylene blue which degraded 84.55% and 48.65% in 170 min, respectively. ZnO-CeO2 nanostructures also showed good sensitivity （0.8331 μA·cm-2·（mol/l）-1） in short response time （10 s） by applying to chemical sensing using ethanol as a target compound by I-V technique. These degradation and chemical sensing properties of ZnO-CeO2 nanostructures are of great importance for the application of ZnO-CeO2 system as a photo-catalyst and chemical sensor.

The Parameters Selection of SMA Optically Activated and Its Application

Shape Memory Alloy (SMA) optically activated is the key technology of optical SMA activator.According to the shape memory mechanism of SMA,researches are done on the activating response time and light wavelength of activating source etc of SMA optically activated to approach the parameters selection of optical activation.SMA has the optimum efficiency in the range of 13 seconds to 27 seconds when SMA is illuminated continuously by wavelength of 675nm;The power of light wave has a low effect on SMA;The longer the activating wavelength,the quicker the response time of SMA activated.If the proper activating time and activating wavelength are adopted, and the structure deformation of composite material of SMA imbedded may be actively controlled,an ideal effect will be gotten.The research provides an evidence for the design of optical SMA activator and is of great significance to its application.The research on smart structure has a wide application prospect.

Synthesis, Characterization and Conductivity of α-Keggin-type Nanoparticles, Co(en)_3PMo_(12)O_(40)·8H_2O with Optical Activity

Polyoxometallates Co(en) 3PMo 12O 40·8H 2O(+,-)[abbreviated as PMo 12-Co(+,-)], nanoparticles were synthesized by the chemical precipitation reaction at room temperature for the first time. They were characterized by means of elemental analyses, IR spectrometry and X-ray diffraction. The images of scanning electron microscopy(SEM) and the results of calculation by using the Scherrer equation for the line widths of the XRD patterns were used to estimate the average particle size of the powder products, which was 40 nm. The results show that the nanoparticle size was affected by starting materials′ concentrations. The particles had a small size and a narrow distribution, when the concentrations of H 3PMo 12O 40·24H 2O and Co(en) 3I 3·H 2O were around 1.7×10 -4 and 1.0×10 -3 mol/L, respectively. When the concentration was increased, there was no significant increase in the particle size, but more polydisperse Co(en) 3(PMo 12O 40) (+, -) were obtained. In poly(ethylene glycol)(PEG) with an average molecular weight(M W) of 600 g/mol and containing LiClO 4[n(O)/n(Li)=100∶1] as the supporting electrolyte, the conductivity of the composite system increases upon the addition of PMo 12-Co(+ or -) nanoparticles, which was measured by the a.c. impedance technique. The interactions among PEG, LiClO 4, PMo 12, and Co can be used to explain that the PMo 12-Co(+ or -) nanoparticles could promote the conductivity of the PEG-LiClO4-PMo12-Co system.

Exploring the band structure of Wurtzite InAs nanowires using photocurrent spectroscopy

Nano Research volume We use polarized photocurrent spectroscopy in a nanowire device to investigate the band structure of hexagonal Wurtzite InAs.Signatures of optical transitions between four valence bands and two conduction bands are observed which are consistent with the symmetries expected from group theory.The ground state transition energy identified from photocurrent spectra is seen to be consistent with photoluminescence emitted from a cluster of nanowires from the same growth substrate.From the energies of the observed bands we determine the spin orbit and crystal field energies in Wurtzite InAs.This information is vital to the development of crystal phase engineering of this important III-V semiconductor.