有色粉体材料对太阳辐射吸收性能的UV-Vis-NIR光谱法表征

进一步研究了粉体材料对太阳辐射吸收能力的定量表征方法 .结果表明 ,当 Vcolored/V(Ti O2 ) (有色粉体与 Ti O2 的体积比 ) <5 %时 ,lg(1 /R) (R是试样对太阳辐射的反射率 )和 Vcolored/V(Ti O2 )呈直线关系 .从直线的斜率和截距可得出粉体材料的吸光系数和最大穿透厚度 .该方法具有普遍性 ,适用于各种有色粉体的测定 .

Analytical Study of Two Differently Ranked Coals Using UV-VIS-NIR Spectroscopy

The characterization of Indian bituminous and subbituminous coal was performed by UVVisible– NIR spectroscopy. Chemical leaching with varying concentration of hydrofluoric acid was conducted on both the samples. Electronic absorption at this region was higher for higher ranked coals. Chemical leaching increased electronic transitions in subbituminous coal with maximum transitions for HF (10%) leached samples. The absorption maximum of benzeneoxygen system was found between 235-270 nm and was showing a red shift with leaching. The characteristic naphthalene ring systems (220 & 280 nm) were masked by the absorption regions of monoaromatic rings;indicating the content of napthalenoid hydrocarbon was very low. The bands observed in the visible region (450nm) were attributed to SO2 in the sample and was showing a red shift. The weak band at the 680 nm was attributed to the Ⅱ-Ⅱ* electronic transitions of the polynuclear aromatic hydrocarbons which also showed red shift with leaching. It was found that the ash content is reduced by 87.5% & 76.2% in bituminous and subbituminous coal respectively with HF (30%) leaching.

墨西哥黄绿色磷灰石的宝石学和光谱学研究

墨西哥Durango地区是宝石级氟磷灰石最丰富的产地之一,对该地磷灰石的研究集中于地质年代学和矿物学标准,宝石学和光谱学资料较少。作为一种发光材料,早期学者主要利用激光诱导的光致发光光谱对未知产地的磷灰石进行研究,缺乏三维荧光光谱的研究。采用基础的宝石学测试、 LA-ICP-MS化学成分分析、红外吸收光谱、激光拉曼光谱、显微紫外-可见-近红外吸收光谱以及三维荧光光谱测试,系统性地对收集到的9颗墨西哥Durango磷灰石进行宝石学和谱学研究,旨在丰富墨西哥磷灰石的光谱学研究数据,并为产地鉴别提供科学依据。化学成分研究表明墨西哥磷灰石中稀土元素丰富,含量较高的La、 Ce、 Pr、 Nd和Sm元素,平均含量分别达3 956、 5 430、 472、 1 596和213μg·g^(-1),具有明显的轻稀土元素富集,重稀土元素亏损的特点,δEu平均值为0.29,负Eu异常显著,Ca/P摩尔比接近岩浆磷灰石的标准值1.68,为岩浆作用的产物,且形成岩浆处于中等还原状态。红外吸收光谱指纹区606和575 cm^(-1)吸收峰强度随方向的变化具有明显的规律性,能为晶体定向提供依据,官能团区显示3 482、 3 538和3 556 cm^(-1)结构水相关的吸收峰。紫外-可见-近红外吸收光谱中,由Nd^(3+)导致的528 nm的单峰和578和585 nm的双峰共同造成了黄绿区明显的透过窗,推测黄绿色体色由Nd^(3+)造成;紫外光区298 nm的吸收峰是造成可见光紫区吸收边的原因,推测由Ce^(3+)导致。三维荧光光谱最强荧光峰(λ_(ex)300 nm/λ_(em)356 nm)由Ce^(3+)的电子跃迁造成,红光区603和647 nm的发射峰由Pr^(3+)和Sm^(3+)的电子跃迁造成,与紫外灯下观察到的暗红色荧光现象相对应,推测暗红色荧光由Pr^(3+)和Sm^(3+)造成。该研究中系统的光谱学特征丰富了墨西哥产地磷灰石的谱学数据,并为产地溯源提供了科学依据。

UV-Vis-NIR Light-deformable Shape-memory Polyurethane Doped with Liquid-crystal Mixture and GO towards Biomimetic Applications

Nature has been inspiring material researchers to fabricate biomimetic functional devices for various applications, and shape-memory polymer materials(SMPMs) have received tremendous attention since the promising intelligent materials possess more advantages over others for the fabrication of biomimetic functional devices. As is well-known, SMPMs can be stimulated by heat, electricity, magnetism, pH, solvent and light. From the viewpoint of practical applications, ultraviolet(UV)-visible(Vis)-near infrared(NIR) light-responsive SMPMs are undoubtedly more advantageous. However, up to now, UV-Vis-NIR light-deformable SMPMs by combining photothermal and photochemical effects are still rarely reported. Here we designed a UV-Vis-NIR light-deformable SMP composite film via incorporating a liquid crystal(LC) mixture and graphene oxide(GO) into a shape-memory polyurethane matrix. The elongated composite films exhibited interesting photomechanical bending deformations with different light-triggered mechanisms,(1) photochemically induced LC phase transition upon UV exposure,(2) photochemically and photothermally induced LC phase transition upon visible-light irradiation,(3) photothermally triggered LC phase transition and partial stress relaxation upon low-intensity NIR exposure. All the deformed objects could recover to their original shapes by high-intensity NIR irradiation.Moreover, the biomimetic circadian rhythms of acacia leaves and the biomimetic bending/spreading of fingers were successfully achieved, which could blaze a way in the field of biomimetic functional devices due to the excellent light-deformable and shape-memory properties of the SMP composite films.

无定形Si-C-O-N涂层的光学性能研究

利用射频磁控溅射法,在SSiC陶瓷表面沉积一层无定形Si-C-O-N涂层,测试了抛光后的涂层和SSiC陶瓷在不同波段的反射率情况。结果表明:在软X射线波段,涂层的反射率小于SSiC陶瓷;在EUV波段,两者反射率基本相当;在UV-VIS-NIR波段,涂层的反射率优于SSiC陶瓷。这主要归因于表面粗糙度和涂层中氧元素对反射率共同作用的结果。

四氯化碳用于纯化单层碳纳米管的研究

利用四氯化碳来纯化单层碳纳米管,并利用UV-VIS-NIR等手段对其进行表征,取得了显著的效果,得到了纯度为90%以上的单层碳纳米管,且产率为15%.

俄罗斯富钒型水热法合成祖母绿的紫外-可见-近红外光谱表征

祖母绿为绿柱石族中铬(Cr)、钒(V)共同致色的宝石种,合成历史悠久,技术不断改进,新配方产品不时出现。近期市场上出现一种新型水热法合成祖母绿,颜色亮丽,外观可与哥伦比亚天然祖母绿媲美,经初步分析发现其为V致色合成祖母绿。为了探究其特征,运用激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)、紫外-可见-近红外(UV-Vis-NIR)分光光度计进行详细研究,旨在获得其化学成分中致色元素含量及UV-Vis-NIR吸收光谱特征,分析致色原因,并寻求与天然祖母绿的相区别的方法,为检测机构提供重要数据信息。化学成分研究表明,该合成祖母绿为纯V致色,具有富V贫铁(Fe)的特征,铜(Cu)在不同批次样品中,含量差别较大,而Cr及其他致色元素含量大多低于检测限。作为对比的传统富Fe型水热法合成祖母绿样品,则具有高Cr高Fe的特征。此外,含有较高的镍(Ni)及微量钛(Ti),锰(Mn),Cu,而V含量则低于检测限。新型合成祖母绿的紫外-可见吸收光谱呈现典型的钒元素的吸收光谱特征,在紫区430 nm、橙红区617 nm处显示两个宽大的吸收带。此外在约390和680 nm附近分别有一肩峰,多数样品在756 nm处有一弱吸收峰。430 nm吸收带归属于V^(3+)的d电子[^(3)T_(1g)(^(3)F)→^(3)T_(1g)(^(3)P)]自旋允许跃迁,617 nm吸收带归属于V^(3+)的d电子的^(3)T_(1g)(^(3)F)→^(3)T_(2g)(^(3)F)自旋允许跃迁,756 nm吸收峰为Cu^(2+)所致,该吸收光谱特征与传统富Fe型合成祖母绿明显不同。天然祖母绿大多具Fe^(3+),Fe^(2+)及Cr^(3+)的吸收光谱组合特征,较容易与该合成祖母绿区分;少数纯V致色天然祖母绿,虽然同样具有V元素特征的吸收峰,但由于同时具有在810~830 nm附近Fe^(2+)的特征吸收带,也能与富V型合成祖母绿区别。近红外区,主要在1 402,1 467和1 895 nm处显示I型水相关吸收峰,也可与天然祖母绿区别。紫外-可见-近红外光谱是鉴定天然祖母绿与合成祖母绿的一个有效手段,但要结合其他鉴定信息,如包裹体、分子振动光谱等,避免新合成配方祖母绿的出现而导致错误的鉴定结论。

Controllable Synthesis of Ag Nanocubes via a Polyol Method

The controllable synthesis of uniform silver nanocubes with high purity is pivotal for the fundamental study of self-assembly and further research on the hollow nanostructures,gold nanocages for instance.Here,Ag nanocubes of different sizes were synthesized by an improved polyol method.With addition of HCl solution,Ag nanocubes with size about 100 nm were obtained under an air atmosphere.And Ag nanocubes with size around50 nm can be produced in a short time under Argon atmosphere with the presence of NaHS instead of HCl.Meanwhile,uniform Ag nanocubes with size larger than 100 nm were also synthesized successfully via adjusting experiment parameters.Results of transmission electron microscopy(TEM)combined with selected area electron diffraction(SAED)show that the Ag nanocubes are single crystalline with six(200)surface plane.In the UV-Vis-NIR optical absorption spectrum,the diple moment resonance absorption peak is changed in the range of 420—500nm with the increase of Ag nanocubes size.

Optimization Conditions for Single-Walled Carbon Nanotubes Dispersion

The sonication-driven dispersion of single-walled carbon nanotubes (SWCNTs) in aqueous surfactant solution has been monitored by UV-vis-NIR spectroscopy and scanning electron microscopy. Dispersion of SWCNTs experiments reveal that the maximum concentration of dispersed SWCNTs corresponds to the maximum UV-vis-NIR absorbance of the solution. With higher surfactant concentration the dispersion rate of SWCNTs increases and low temperature sonication is required to achieve maximum dispersion. Dispersion of higher SWCNT concentrations requires longer sonication time. For effective dispersion the optimal concentration of surfactant is 1.5 wt%, the concentration of SWCNTs that can be homogeneously dispersed in aqueous solution is about 0.4 mg/ml.

Growth, Structural, Spectral and Optical Studies on Pure and L-Alanine Mixed Bisthiourea Cadmium Bromide (LABTCB) Crystals

Pure bisthiourea cadmium bromide (BTCB) and 1 mole % L-alanine mixed bisthiourea cadmium bromide (LABTCB) single crystals have been grown by slow evaporation method. The grown crystals have been characterized by single crystal XRD analysis, powder XRD analysis, FTIR analysis, UV-Vis-NIR analysis and SHG studies. XRD analysis confirms the crystalline nature of the materials. The addition of L-alanine changes the crystal structure from orthorhombic to tetragonal. The presence of various functional groups present in the pure BTCB and LABTCB crystals have been confirmed by FTIR analysis. The UV-Vis-NIR spectrum shows the transmission characteristics of the crystals. The SHG study depicts the nonlinear optical efficiency of the crystals.

The Influence of Benzophenone Substitution on the Physico-Chemical Characterizations of 8-HydroxyQuinoline NLO Single Crystals

Single crystals of 8-Hydroxyquinoline(8-HQ) and Benzophenone substituted 8-HydroxyQuinoline(B8-HQ) are grown by slow evaporation of acetone at room temperature. Coloured crystals of 8-HQ and B8-HQ with good optical quality of dimensions 54 × 3 × 1.5 mm3 and 27 × 3 × 1 mm3 are harvested. Single crystal X-ray diffractometer was utilized to measure the unit cell parameters and to confirm the crystal structure. The presence of various functional groups in the molecule was ascertained by FTIR spectral analysis. The cut-offwavelength of 8-HQ andB8-HQwas centered at 350 and 356 nm. The functional groups in the molecule are elucidated by 1H and 13C-NMR spectral analyses. Kurtz Perry test confirms the SHG in8-HQ andB8-HQ single crystals.

Spectroscopic Investigation of Modified Single Wall Carbon Nanotube (SWCNT)

We have investigated the effects of chemical treatment on Single Wall Carbon Nanotube (SWCNT) before and after being modified with HNO3/H2SO4 by Raman, FTIR and UV-Vis-NIR spectroscopy. The results show successful carboxylation of the CNT sidewalls as observed from FTIR and UV-Vis-NIR spectroscopy. This successful functionalization is achieved in 6-8 hrs of refluxing. We also report changes in the first and second order Raman spectra of SWNTs functionalized with oxygenated groups. During the experiment, we observe some important Raman features: Radial breathing mode (RBM), Tangential mode (G-band), and Disordered mode (D-band);which are affected due to the chemical oxidation of carbon nanotubes. We found that the ratio of D- to the G-band intensity (Id/Ig), increase after functionalization and the RBM mode in acid treated SWCNTs is almost disappeared.

Studies on Optical, Mechanical and Electrical Properties of Organic Nonlinear Optical p-Toluidine p-Toluenesulfonate Single Crystal

The optically transparent and bulk single crystal of p-Toluidine p-Toluenesulfonate (PTPT) was grown by slow evaporation technique. The lattice parameters and crystallinity of the grown crystal were estimated by single crystal XRD. The optical absorption of the crystal was recorded using the UV-Vis-NIR spectrophotometer. The optical bandgap and optical constants of the material were determined by using absorption spectrum. The refractive index of the grown crystal has been determined using the Brewster angle method. The dielectric constant and dielectric loss were measured as a function of frequency and temperature for the grown crystal. Nonlinear optical properties were performed to confirm the SHG efficiency of the grown crystal. Hence, PTPT is an excellent NLO material with enhanced SHG efficiency required for important applications in the field of optoelectronic and photonics. This material exhibits NLO behaviour remarkably due to its better optical and dielectric properties.

Nanoparticles of In2O3/SnO2 (90/10) and (80/20) at Two Different Proportions and Its Properties

ITO nanoparticles were obtained by combustion reaction of urea as fuel. The gel form structures were fired at 350°C in furnace for 20 min to yield powdery products and these products were calcined to five different temperatures from 100°C to 500°C for an hour to yield ITO powders. From the scanning electron microscopy (SEM) photographs and particle size analysis the average sizes of the cubic particle of powders are found to be less than 15 nm and less than 20 nm respectively. The ratio of doping concentration In/Sn is 90/10 and 80/20. The X-ray diffraction (XRD) data were evaluated by Scherer equation for the estimation of the average crystal size of the powders (less than 20 nm) for 90/10 and (less than 25 nm) for 80/20. The synthesized ITO powder characterized by XRD, UV-Vis-NIR and PL shows high specific surface area and possesses small primary crystallite size and good optical band gap.

Growth, Crystal Structure and Characterization of a New Single Crystal: Lithium Sodium Acid Phthalate (LiNaP), for Third Order Nonlinear Optical Applications

A new alkali metallo-organic single crystal of Lithium Sodium Acid Phthlate (LiNaP) complex has been synthesized from aqueous solution in the equimolar ratio 3:1:2. Transparent and bulk single crystals of dimension 9 × 4 ×2 mm3 have been grown from the conventional slow-cooling technique. The crystal structure of the compound has been solved from single crystal X-ray diffraction. The compound 2[C8H4O3]4-Li3+Na+ crystallizes in triclinic system with a space group of Pī having cell dimensions a = 7.5451(2) ? b = 9.8422(3) ? c = 25.2209(7) ? α = 80.299(2);β = 89.204(2);γ = 82.7770(10). FTIR measurement was carried out fo? LiNaP to study the vibrational structure of the compound. The various functional groups present in the molecule and the role of H-bonds in stabilizing the crystal structure of the compound have been explained. Optical absorption properties were studied for the grown crystal using UV-Vis-NIR spectrum. Thermal measurements were carried out for LiNaP to determine the thermal strength as well as to ascertain the hydrated nature of the crystal. Third order nonliner optical studies have also studied by Z-scan techniques. Nonlinear absorption and nonlinear refractive index were found out and the third order bulk susceptibility of compound was also estimated. The results of all studies have been discussed in detail.

Photo-Dimerization Characteristics of Coumarin Pendants within Amphiphilic Random Copolymer Micelles

The photo-dimerization characteristics of coumarin pendants within amphiphilic random copolymer micelles in aqueous solution was comprehensively investigated using various selected wavelength light in the UV-Vis-NIR region. The time-dependent photo-dimerization degree （PD） changes in the photo-dimerization experiments showed saturating behaviors with intensity-independent of PDmax values at 28%, 44%, 92%, 85%, 36%, 35%, 32% and 31% for 254, 288, 320, 360, 400, 500, 650 and 900 nm irradiations, respectively. The irradiation experiments at 254 and 288 nm announced the occurring of an asymmetric equilibrium of photo-dimerization and photo-cleavage at the used conditions. Both the alternative irradiation cycles of 360 and 254 nm, 650 and 254 nm showed a partially, but evidently reversible photo-dimerization tendency.

Effect of dopant concentration on the spectra characteristic in Zr^(4+) doped Yb:Nd:LiNbO_3 crystals

A series of Yb：Nd：LiNbO3 crystals tridoped with various concentrations of Zr4＋（1 mol.%, 2 mol.% and 4 mol.%） were grown by the Czochralski technique from the congruent melt. The X-ray powder diffraction, UV-Vis-NIR absorption spectra and IR transmittance spectra were measured to analyze the crystal composition and defect structure. The Zr4＋, Yb3＋ and Nd3＋ ions in LiNbO3 crystal had two effects： volume compensation effect and ion valence state compensation effect. The Zr O2 doping threshold concentration was nearly 2.0 mol.%. The fluorescence emissions of Nd3＋ ions and Yb3＋ ions were observed under 808 nm excitation. The intensity of fluorescence emissions enhanced with the increasing of the Zr4＋ doping concentrations. The Zr：Yb：Nd：LiNbO3 crystals with 4 mol.% doping concentration of Zr4＋ ion revealed strong emission around 1 μm, which is of great significance for laser materials.

Antimicrobial effects by silver–indium–tantalum oxide thin film in visible light

This study focuses on the antimicrobial effects in silver-indium-tantalum oxide(Ag–InTaO)thin films.A stack of alternated layers of Ag(7 nm),In_(2)O_(3)(14 nm)and Ta_(2)O_(5)(10 nm)was sequentially deposited by sputtering.Then this as-deposited stack of films was rapidly annealed at three selected temperatures 700,800 or 900℃ for 5 min to allow the formation of complex oxides.Results from material characterization indicate that annealing help to form complex oxides,intermetallic compounds and Ag particles on the top surface.These features lead to the improved antimicrobial effect against E.Coli.under visible light by Ag–InTaO.