不对称菁染料敏化纳米TiO2的光生电流过程

用光电化学方法研究了不对称菁类染料敏化TiO2 纳米结构电极的光电转换过程 .结果表明 ,该染料的电子激发态能级位置与TiO2 纳米粒子导带边位置匹配较好 ,光激发染料后 ,其激发态电子可以注入到TiO2 纳米多孔膜的导带 ,从而使TiO2 纳米结构电极的吸收光谱和光电流谱红移至可见光区 ,其IPCE(Incidentphoton to electronconversionefficiency)值最高可达 84.3 % .并进一步结合现场紫外 可见吸收光谱研究了外加电势对激发态染料往TiO2 纳米多孔膜注入电子过程的影响     

Morphology of Nanostructured Films for Environmental Applications: Simulation of Simultaneous Sintering and Growth

A sequential Brownian dynamics approach was used to establish the morphological evolution of a nanostructured particle deposit accounting for random diffusion, particle–particle and particle–surface interactions through van der Waals forces, and sintering of deposited particles. Monodisperse (30nm radius) titanium dioxide particles were used in the simulations. A linear sintering law rate expression was used to account for the decrease in total surface area of the deposit. Characteristics such as packing thickness, total surface area, and fractal dimension are reported as a function of time during the deposition process. Sintering resulted in higher fractal dimensions (as defined) for the deposits, and elevated temperatures resulted in more compact deposits.     

Application of Spectroscopy and Microscopy Techniques in Surface Coatings Evaluation: A Review

Abstract: This article presents a review of the published articles related to the novel application of spectroscopy and microscopy methods in paint and coatings quality evaluation. Traditional and simple techniques have been used in paint and coating industry for many years and proven to be effective. However, the paint and coating industry faces new formulations with nontraditional applications. Therefore, the industry needs to adjust itself with the current sophisticated production and testing methods. There are a number of modern microscopy and spectroscopy techniques that can be utilized in the paint and coating industry for a better understanding of the product quality and/or application performance. This, in particular, is highly applicable in modern and nontraditional applications such as nanotechnology and smart coatings. Though importance of spectroscopy and microscopy methods is being increasingly recognized in the industry, there is no current comprehensive review available to highlight the need for novel application of these techniques in surface coatings evaluations.     

利用非规整膜系实现宽角度入射减偏振、减反射薄膜的研究

利用非均匀膜系理论对宽角度入射减偏振、减反射薄膜进行优化设计,分析了在宽角度入射的情况下,偏振光产生透过率不同的原因,选取了Na3AlF6、Ta2O5和Al2O3三种不同折射率材料,采用BK7作为基底,模拟设计了光谱区在500～560 nm波段、入射角为0~70°之间的多层减偏振、减反射薄膜,设计结果表明,薄膜的透过率得到大幅度提高.     

Significant influence of particle surface oxidation on deposition efficiency, interface microstructure and adhesive strength of cold-sprayed copper coatings

The critical velocity for particle deposition in cold spraying is a key parameter, which depends not only on the material type, but also the particle temperature and oxidation condition. The dependency of deposition efficiency of cold spray Cu particles on the particle temperature and surface oxidation was examined. The effect of particle surface oxide scales on the interfacial microstructure and adhesive strength of the cold-sprayed Cu coatings was investigated. The results show that the deposition efficiency significantly increases with increasing the gas temperature but decreases with augmenting the oxygen content of the starting powder. The oxide inclusions at the interfaces between the deposited particles inhibit the effective bonding of fresh metals and remarkably lower the bond strength of the deposited Cu coatings on steel.     

Influence of annealing treatment on the microstructure and mechanical performance of cold sprayed 304 stainless steel coating

In this study, 304 stainless steel coatings were deposited on interstitial-free steel substrate by cold spraying method. The effect of annealing treatment on microstructure, microhardness, ultimate tensile strength and fracture performance of the coatings were studied. The results showed that annealing treatment had made a dominant contribution to heal up the incomplete interfaces between the deposited particles. Both of the microstructure and the mechanical properties have been obviously optimized by annealing treatment. In addition, the coating microhardness decreased from 345 HV_0.2 for the as-sprayed coating to 201 HV_0.2 for the annealed coating. The coating ultimate tensile strength increased from 65 MPa for the as-sprayed coating to 357 MPa for the annealed coating, which resulted from the increase of the metallurgically bonded areas in the coating induced by annealing treatment. Fracture morphology of the coatings also revealed that annealing treatment changed the fracture character of the cold sprayed 304 stainless steel coating from brittle type to plastic type.     

Investigation of Cell Structure and Expansion Ratio of Microcellular Polypropylene Nanohomocomposites Prepared by a Solid-State Process

Microcellular poly(propylene-ethylene) random copolymer (r-PP-PE)/nanoclay (nanocomposite) and r-PP-PE/nanoclay/polypropylene fibers (nanohomocomposite) were autoclave-foamed via a solid-state microcellular foaming process using supercritical N₂ as a foaming agent. Polypropylene grafted with maleic anhydride (PP-g-MA) was used as a compatibilizer. Amount of PP-g-MA to nanoclay was 3:1. This study investigated the effects of clay content and the presence of polypropylene fiber on the expansion ratio and cell morphology of the samples. The results indicated that nanoclay increased the expansion ratio of the samples, but the expansion ratio for nanohomocomposites was slightly lower than the nanocomposites. In addition, scanning electron microscopy (SEM) observation showed that the nanoclay decreased the cell size and increased the cell density, except for the nanocomposite with the highest nanoclay content, 3 wt%, which had larger cell size compared to the samples with 1.5 wt% nanoclay and less. On the other hand, the simultaneous presence of nanoclay and polypropylene fibers synergistically increased the cell nucleation effect; thus there was a dramatic increase in cell density. The Differential scanning calorimetry (DSC) analysis showed that the microcellular foaming process decreased the crystallinity of both types of samples.     

Effect of vacuum heat treatment on tensile strength and fracture performance of cold-sprayed Cu-4Cr-2Nb coatings

The previous study [1] indicated that dense thick Cu-4Cr-2Nb coatings could be formed by cold spraying, and the post-spray heat treatment could significantly influence the microstructure and microhardness of the as-sprayed Cu-4Cr-2Nb coatings. In this study, the tensile strength and fracture performance of the Cu-4Cr-2Nb coatings after annealing were investigated. The vacuum heat treatment was conducted under 10⁻² Pa at 850 °C for 4 h. Results showed that the heat treatment had a great contribution to the healing-up of the incompleteness of the interfaces between the deposited particles. In addition, the coating microhardness decreased from 156.8 ± 4.6 Hv_0.2 for the as-sprayed coatings to 101.7 ± 4.5 Hv_0.2 for the annealed ones. The mean tensile strength of the annealed coatings was approximately 294.1 ± 36.1 MPa compared to that of 45.0 ± 10.5 MPa for the as-sprayed ones, which results from the partially metallurgically bonded zones between the deposited particles inducing by the heat treatment process.     

真空紫外和极紫外相干光源的研究及进展

本文简明扼要地介绍和评论了真空紫外和极紫外波段相干光源研究的现状和发展前景 ,重点包括 :真空紫外和极紫外波段相干光源的产生机制 ,理论描述 ,实验方法 ,以及一些典型的实验结果。最后对该领域的发展前景做了简要的评述。     

Advanced oxidation of Reactive Blue 181 solution: A comparison between Fenton and Sono-Fenton Process

In this work, the decolorization of C.I. Reactive Blue 181 (RB181), an anthraquinone dye, by Ultrasound and Fe²⁺ H₂O₂ processes was investigated. The effects of operating parameters, such as Fe²⁺ dosage, H₂O₂ dosage, pH value, reaction time and temperature were examined. Process optimisation [pH, ferrous ion (Fe²⁺), hydrogen peroxide (H₂O₂), and reaction time], kinetic studies and their comparison were carried out for both of the processes. The Sono-Fenton process was performed by indirect sonication in an ultrasonic water bath, which was operated at a fixed 35-kHz frequency. The optimum conditions were determined as [Fe²⁺] = 30 mg/L, [H₂O₂] = 50 mg/L and pH = 3 for the Fenton process and [Fe²⁺] = 10 mg/L, [H₂O₂] = 40 mg/L and pH = 3 for the Sono-Fenton process. The colour removals were 88% and 93.5% by the Fenton and Sono-Fenton processes, respectively. The highest decolorization was achieved by the Sono-Fenton process because of the production of some oxidising agents as a result of sonication. The paper also discussed kinetic parameters. The decolorization kinetic of RB181 followed pseudo-second-order reaction (Fenton study) and Behnajady kinetics (Sono-Fenton study).     

先进固体核磁共振揭示苯硼酸-壳聚糖纳米粒子非均匀结构和相容性

该文采用先进的固体核磁共振技术研究了壳聚糖-聚3-丙烯酰胺基苯硼酸纳米粒子非均匀结构和高分子间的相容性．¹³C CPMAS 实验表征了壳聚糖与苯硼酸结合后的构象变化,2D ¹³C-¹H HETCOR 实验进一步证明了壳聚糖在界面处通过硼酸配位作用与苯硼酸链紧密相连．2D ¹H-¹H 自旋交换和扩散实验阐明了壳聚糖和聚苯硼酸的界面混合性,相分离尺度大约为15-20 nm．     

铬掺杂氧化锌薄膜的超声喷雾法制备及其光学与磁学性质

用注射超声喷雾法将前驱体由针管直接送入超声喷头内,在石英基板上制备Zn_(1-x)Cr_xO(x=0.0,0.01,0.03,0.05)薄膜。采用X射线衍射仪、扫描电子显微镜、荧光光谱仪、紫外-可见分光光度计、振动样品磁强计(VSM)等对薄膜的结构、光学和磁学性质进行测量。实验结果表明,未掺杂的ZnO薄膜为六角纤锌矿结构,沿着c轴(002)择优取向,而Cr掺杂抑制了薄膜的c轴择优取向性;掺杂后的薄膜平均晶粒尺寸均增大,且当x=3%时,晶粒尺寸最大,达31.4nm。扫描电镜(SEM)下薄膜呈球形颗粒状,并且在x=5%下,薄膜出现了长条状的微观形貌。Cr掺杂使样品的光致发光谱(PL)发生了很大的变化:未掺杂的样品的PL谱在378nm处存在一个紫外发射峰,对应于550nm附近还存在一个由于缺陷态引起的绿光发射峰;掺Cr样品只有在350~550nm的很宽的范围内存在一个发射峰,对其进行高斯拟合后,发现掺Cr量为x=1%,3%,5%下样品均存在V_(Zn)(锌空位)、Zn_i(Zn间隙位)、V_(Zn)~-(带一个电子的锌空位)内部缺陷态,且当x=3%时,V_(Zn)最多。Cr的掺杂使得薄膜的带隙增大,并且x=3%时,禁带宽度最大,达到3.374eV。掺Cr的三个样品均具有室温铁磁性,且x=3%样品的磁化强度最大,其与V_(Zn)(锌空位)最大相对应,验证了Cr~(3+)和V_(Zn)的缺陷复合体是ZnO∶Cr样品具有稳定的铁磁有序的最有利条件的理论预测。     

钛表面FHAP涂层的电沉积制备及其FTIR特征研究

在含有Ca2+,PO3-₄和F-的电解液中,用电化学恒电流方法,在工作电流为0.9 mA温度为60 ℃的条件下沉积60 min,在医用钛(Ti)表面上制得含氟羟基磷灰石(FHAP)涂层。采用扫描电镜(SEM)、能量弥散X射线谱(EDS)、X射线衍射(XRD)对涂层进行表征,用傅里叶变换红外光谱(FTIR)考察了氟离子的引入对涂层构象和生物活性的影响。结果表明：氟部分取代磷灰石中的羟基,FHAP晶格常数变小,涂层相貌由疏松的微米级的菊花瓣状变化为致密的纳米级的尖锥状。FTIR分析表明,涂层中羟基的伸缩和弯曲振动模式的对称性发生了改变,模拟体液浸泡后涂层覆盖碳磷灰石,涂层生物活性良好。     

固体核磁共振研究固体酸催化剂酸性进展

酸性直接与固体酸催化剂的活性相关,因此研究固体酸催化剂的酸性受到了科研工作者的广泛关注. 固体核磁共振技术已经成为研究固体酸催化剂酸性的一种强有力的工具. 该文介绍了固体核磁共振的特点和各种常用技术,着重综述了固体核磁共振研究固体酸催化剂酸性的进展.     

原子吸收光谱法测定与分析榛子抗寒性的研究

以榛子一年生枝条为试材,利用原子吸收光谱法和电导法分别测定与分析榛子3个种(6个无性系)不同低温处理后的K+渗出率和电解质渗出率,并建立了各无性系的低温-K+渗出率及低温–电解质渗出率回归模型。结果表明：利用2种方法综合评价各无性系抗寒能力结果一致,原子吸收光谱法测定K+渗出率指标可作为榛子无性系抗寒性的一种早期鉴定手段;6个无性系抗寒性大小排序为：C₇R₇＞Z-9-40＞C₆R₁＞CS₂R₁＞Z-9-22＞Z-9-30,3个种的抗寒性强弱顺序为：平榛＞平平欧杂交榛＞平欧杂交榛;各无性系半致死温度在-26～40 ℃之间。     

冷原子吸收法测定人发和中成药中汞

本文以空气作载气考察了各种实验条件对冷原子吸收法测定汞的影响 ,在最佳实验条件下 ,汞的灵敏度为 1 1μg·L-1,检出限为 0 5 μg·L-1,校正曲线线性范围 0～ 4 0 μg·L-1。采用密封式压力消解样品 ,以HNO3、H2 SO4和H2 O2 ( 4 + 1+ 1)为氧化剂 ,SnCl2 为还原剂 ,成功地用于人发标样和不同种类中成药中汞的测定 ,相对标准偏差分别为 3 2 % ,1 5 %和 0 2 4 % ,回收率 94 6%～ 10 2 % ,用方便节省的空气代替高纯氩气作载气完全可行。     

微波消解-冷原子荧光法测定煤中痕量汞

微波消解技术具有样品溶解完全、污染少、节约试剂和方便快捷等特点。文章采用微波消解预处理煤样 ,并用冷原子荧光法测定样品中的痕量汞。采用硝酸 盐酸 氢氟酸消解体系 ,进行了微波消解条件的选择 ,并考察了载气流量、屏蔽气流量、负高压和干扰等对测定的影响。在选定的操作条件下 ,汞的检出限为0 0 3ng·mL-1,相对标准偏差 (n =7)小于 5 %。方法准确、快速和方便 ,利用国家标准参考物质煤飞灰GBW 0 84 0 1验证了方法的准确度 ,测定值与参考值基本吻合     

Study on the Compatibility of SMA and Composite Materials by Holographic Interferometry

With the help of holographic interferometry a study is conducted on the compatibility of SMA (shape memory alloy) and epoxy resin composite material. The paper gives experiment results and analysis which show that after coupling SMA with the composite material, the flexural rigidity of composite material is somewhat reinforced. Under certain conditions, SMA and the epoxy resin composite material are compatible.     

Study on the Compatibility of SMA and Composite Materials by Holographic Interferometry

With the help of holographic interferometry a study is conducted on the compatibility of SMA (shape memory alloy) and epoxy resin composite material. The paper gives experiment results and analysis which show that after coupling SMA with the composite material, the flexural rigidity of composite material is somewhat reinforced. Under certain conditions, SMA and the epoxy resin composite material are compatible.