Physical, chemical and optical properties of aqueous L-arginine phosphate (LAP) solution

The mathematical modelling of the solution growth of high quality single crystals requires a good understanding of the fluid properties. In addition to the physical and mechanical properties a detailed knowledge of the optical parameters is required to study the dynamics of the crystal growth process. Measurements of polarizability, refractive index, optical dispersion, solubility, pH, viscosity, and density were performed on aqueous L-Arginine phosphate (LAP) solutions. The index of refraction was measured with an Abbe refractometer at four different wavelengths. Optical dispersion was calculated using the Cauchy's equation. Effects of the density and kinematic viscosity of the LAP solution are discussed in terms of the dimensionless Grashof and Reynolds number allowing a better understanding of the benefits of operating under the micro-g conditions of space for the solution growth of single crystals. The Cauchy's formula and Sellmeier formula of the refractive index have been used to determine both the gradients dn/dc and dn/dT as a function of wavelength and the polarizability of the LAP solution. The polarizability of the LAP crystal, ₂, was found to be 14.50 cm³/mol and this value was in good agreement with experimental data obtained and analyzed using the well-known Lorentz-Lorenz formula.     

水溶液提拉法实现KDP单晶柱面扩展

利用水溶液提拉法,把籽晶放在育晶器的底部,沿〈110〉方向进行提拉生长,生长出了截面较大的KDP单晶12mm×12mm×31mm。〈110〉方向的生长速度较传统的溶液降温法得到了一定的提高。这主要是由于提拉使得晶体在提拉方向上的溶质边界层梯度持续发生变化造成的。     

聚合物P(NIPAM-AM-NPA)的合成及溶液性能

以丙烯酸壬基酚聚氧乙烯酯(NPA)、丙烯酰胺、N-异丙基丙烯酰胺为单体,采用自由基水溶液聚合方法制备了水溶性共聚物P(NIPAM-AM-NPA)。采用FT-IR、1H-NMR对该共聚物以表征;研究了共聚物浓度、温度以及不同电解质对共聚物溶液性能的影响。结果表明,随着盐浓度的增加,聚合物溶液表观黏度有较大幅度上升。在相同情况下,NaCl的增粘效果最为显著,而MgCl2和CaCl2则影响不大。该共聚物的盐水溶液在升温条件下可保持良好的增粘作用,适当条件下还会出现黏度随温度升高而上升的独特现象。     

基于NIPAM和HEMA的温敏性共聚物水溶液性能研究

以N-异丙基丙烯酰胺(NIPAM)、甲基丙烯酸羟乙酯(HEMA)、丙烯酰胺(AM)、丙烯酸(AA)为原料,采用水溶液自由基聚合法制备了N-异丙基丙烯酰胺基温敏水溶性共聚物P(NIPAM-HEMA-AM)和P(NIPAM-HEMA-AM-NaAA)。研究了无机盐及聚合物结构对共聚物低临界溶解温度(LCST)的影响,考察了共聚物浓度、盐浓度、表面活性剂浓度对共聚物溶液流变性能特别是粘温特性的影响。结果显示,随着盐浓度的增加,共聚物溶液的LCST呈下降趋势。共聚物浓度较高时,在LCST附近表现出显著的升温增稠性。在P(NIPAM-HEMA-AM-NaAA)溶液中加入NaCl后溶液黏度增加,升温增稠效应明显。     

导模法生长蓝宝石单晶光纤的缺陷和光学特性研究

通过导模法(EFG)成功生长了蓝宝石单晶光纤(直径400~1000 μm, 长度500 mm)。光纤的横截面大致为圆形, 侧面无明显的小面, 直径变化小于40 μm。本研究对晶体缺陷, 例如微气泡, 包裹物和生长条纹等进行观察与分析, 得出: 大多数微气泡是球状的, 且存在于光纤的外侧缘; 在蓝宝石光纤外侧面也观察到少量的钼包裹物元素; 新模具在前几次使用中往往会产生更多的钼夹杂物, 在多次使用后降低。通过对熔体膜流体流动的实验和数值模拟, 研究蓝宝石光纤中微气泡尺寸和分布, 实验和数值模拟的结果显示出良好的一致性。微气泡的分布取决于熔体膜处的流体流动模式, 流体流动的涡流使微气泡在热毛细对流作用下移动到蓝宝石光纤外侧缘。633 nm处的吸收损耗为9 dB/m, 包裹物和表面不规则性会增加散射损耗。     

真空蒸发制备Cd(Se,S)薄膜及其光学性能研究

利用真空蒸发技术在CdS粉末中掺入不同比例的Se粉末作源,选择合适的工艺条件在玻璃衬底上获得了性能稳定的Cd(Se,S)薄膜,薄膜为纤锌矿结构,具有沿[002]晶向的择优取向.Cd(Se,S)薄膜为n型材料,在可见光范围内具有良好的透过率.随Se成分的增加,薄膜由透明橘黄色变为透明棕红色,吸收限向长波方向移动.     

水溶液中Sm-Co薄膜的制备及其磁学性质

在以甘氨酸为络合剂的水溶液中,利用恒电位技术成功制备出了高Sm含量(质量分数为62.2%)的Sm-Co合金薄膜。循环伏安曲线表明,甘氨酸在电化学沉积Sm-Co合金薄膜的过程中具有重要作用。络合物[CoⅡ-SmⅢ(Gly-)2(HGly±)]3+的形成有利于Sm和Co在相对低电位下的共沉积。X射线衍射仪(XRD)分析结果表明,镀态合金膜为非晶态,经过退火处理后,合金膜由非晶态转化为多晶态结构,出现了永磁相Sm2Co17,合金膜的矫顽力明显增大。     

低温保护剂溶液固化性质的DSC研究

利用差示扫描量热仪,研究了乙二醇、丙三醇、1,3丙二醇、1,3丁二醇和2,3丁二醇水溶液的水合性质、玻璃化转变温度和反玻璃化转变温度,得出了这些性质与溶液浓度的关系.研究发现未冻水含量在低浓度时没有明显的规律性,而在中高浓度则随着溶液浓度的增大而增大.对于玻璃化转变,中低浓度区溶液形成的是部分晶体的玻璃态,紧接着在高浓度区溶液形成完全的玻璃态.部分玻璃化的温度不随浓度变化,而玻璃化的温度随浓度增大而升高.形成反玻璃化的浓度范围比较小,反玻璃化的温度随浓度增大而升高.保护剂在玻璃化转变温度和反玻璃化转变温度的明显差异,则反映它们在玻璃化能力方面的强与弱.     

纳米ZnO中Al的掺杂及其在水溶液中光催化性能的研究

分别用热物理法制备ZnO、掺Al/Zno和光化学反应沉积制备掺Al/ZnO的纳米粉体材料,采用XRD,TEM等手段研究了ZnO超微粒子结构与形貌.在Al掺杂ZnO纳米晶的水相体系中,通过吸光度、脱色率的测定证实了Al掺杂有效的改善了ZnO对亚甲基蓝(MB)的光催化降解性能.Al掺杂ZnO纳米晶较普通氧化锌有更好的光催化活性.效果最好的是热物理法掺Al/ZnO对亚甲基蓝的降解.     

Single-crystal oxoborate (Pb3O)2(BO3)2WO4: Growth and characterization

An oxoborate, (Pb₃O)₂(BO₃)₂WO₄, has been prepared by solid-state reaction methods below 620 °C. Single-crystal XRD analysis shows that it crystallizes in the orthorhombic group Cmcm with a = 18.480(4) Å, b = 6.3567(13) Å, c = 11.672(2) Å, Z = 4. The crystal structure is composed of one-dimensional 1/∞ [Pb₃O]⁴⁺ chains formed by corner-sharing OPb₄ tetrahedra. BO₃ and WO₄ groups are located around the chains to hold them together via PbO bonds. The IR spectra further confirmed the presence of BO₃ groups. Furthermore we have performed theoretical calculations by employing the all-electron full potential linearized augmented plane wave (FP-LAPW) method to solve the Kohn Sham equations. Starting from our XRD data we have optimized the atomic positions by minimizing the forces. These are used to calculate the electronic band structure, the atomic site-decomposed density of states, electron charge density and the chemical bonding features. The calculated electronic band structure and densities of states suggest that this oxoborate possesses a wide energy band gap. The valence band maxima and the conduction band minima are located at Y point in the Brillouin zone resulting in a direct energy band gap of 2.3 eV using the local density approximation and 2.6 eV for the Engel–Vosko generalized gradient approximation. This compares well with our experimentally measured energy band gap of 2.9 eV. From our calculated electron charge density distribution, we obtain an image of the electron clouds that surround the molecules in the unit cell of the crystal. The chemical bonding features were analyzed and the substantial covalent interactions are observed between Pb and O, B and O and W and O atoms.     

阳离子型纤维素醚溶液性质的研究

用激光光散射仪研究了不同pH值时一种高电荷密度阳离子纤维素醚(KG-30M)的稀溶液性质,由不同角度的流体动力学半径(Rh),及根均方旋转半径Rg与Rh比值推断其形状不规则,但接近于球形。进而借助流变仪详细研究了三种不同电荷密度阳离子纤维素醚的浓溶液,讨论了浓度、pH值及其自身电荷密度对其流变性能的影响,随浓度升高,牛顿指数(n)先下降后发生波动甚至回升,3%(质量分数)时出现触变性行为。适中的电荷密度有利于得到较高的零切黏度,pH对其黏度影响不大。     

Process-Parameter-Dependent Optical and Structural Properties of ZrO(2) MgO Mixed-Composite Films Evaporated from the Solid Solution

The process-parameter-dependent optical and structural properties of ZrO(2)MgO mixed-composite material have been investigated. Optical properties were derived from spectrophotometric measurements. By use of atomic force microscopy, x-ray diffraction analysis, and energy-dispersive x-ray (EDX) analysis, the surface morphology, grain size distributions, crystallographic phases, and process-dependent material composition of films have been investigated. EDX analysis made evident the correlation between the oxygen enrichment in the films prepared at a high level of oxygen pressure and the very low refractive index. Since oxygen pressure can be dynamically varied during a deposition process, coatings constructed of suitable mixed-composite thin films can benefit from continuous modulation of the index of refraction. A step modulation approach is used to develop various multilayer-equivalent thin-film devices.     

Physical Properties and Thermal Decomposition of Aqueous Solutions of 2-Amino-2-hydroxymethyl-1, 3-propanediol (AHPD)

Physical properties such as density, viscosity, refractive index, surface tension, and thermal stability of 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) were experimentally measured. All the experimental measurements were made over a wide range of temperatures from (298.15 to 333.15) K and AHPD concentrations of (1, 7, 13, 19, and 25) mass%. An overall decrease in all the measured physical properties was observed with increasing temperature. The experimental results are presented as a function of temperature and AHPD mass fraction. All the measured physical properties were correlated as a function of temperature. Thermal decomposition of pure and aqueous solutions of AHPD was investigated using a thermo-gravimetric analyzer (TGA) at a heating rate of 10 K · min⁻¹.     

二氧化钒智能节能材料的溶液法制备与光学性能

VO2智能控温材料由于可随环境温度变化自主调节光波透反射特性,从而可以机敏地调整室内温度,实现冷热双向调节,达到冬天保暖、夏天保冷的效果,而备受关注,成为了下一代智能窗的首选材料.VO2材料研究需要解决以下问题:包括纯相M/R VO2的控制合成;相变温度的降低及其变化温度范围的调控;提高二氧化钒涂层的可见光透过率,以满足建筑的采光要求以及廉价可重复制备方法的开发等.报道了化学溶液制备方法的若干新结果,并指出廉价的化学溶液制备方法可能是VO2智能控温材料产业化应用的重要解决方案.     

氟化类金刚石(F-DLC)薄膜的红外分析

以CF4和CH4为源气体,利用射频等离子体增强化学气相沉积法,在不同条件下制备了氟化类金刚石(F-DLC)薄膜,并进行了退火处理。红外分析表明,F-DLC薄膜中主要有C-Fx(x=1,2,3)、C-C、C-H2、C-H3和C=C化学键等。低功率下制备的薄膜主要由C-C、CF和CF2键构成,功率增加时,薄膜内C-C键含量相对增加;气体流量比R(R=CF4/[CF4 CH4])增大,薄膜内F的含量增加,C-C键相对减少;高温退火后,薄膜内部分F和几乎全部的H从膜内逸出,薄膜的稳定温度在300℃以上。低功率、高流量比下制备的薄膜,F含量相对较大,介电常数较低。     

水溶液电沉积稀土合金膜的结构和性能研究

综述了水溶液中电沉积稀土合金膜的结构与性能的研究现状.其中结构包括显微结构、非晶形成规律、晶化动力学;性能涉及磁性、析氢电催化行为、耐腐蚀性、力学性能及光学性能.水溶液中电沉积稀土合金膜在一定的制备条件下具有非晶态结构,由于其优异的磁学、析氢电催化、耐腐蚀、力学及光吸收性能,已经应用于镀覆大的非平面电子装置、磁泡记忆元件、高温超导薄膜、磁光记录材料、电极材料、发光材料、储氢材料以及表面工程技术等领域,同时对水溶液中电沉积稀土合金膜的研究进行了展望.     

氟磷灰石对酸性水溶液中铀(VI)的去除研究

随着全球核能的开发利用, 铀已成为土壤、地表水和地下水的常见污染物, 从含铀废水中去除铀(VI)已成为迫切需要。本工作以氟化钙、焦磷酸钙、氢氧化钙为反应原料合成氟磷灰石, 系统研究了其对铀(VI)的去除性能并采用不同测试手段对吸附铀(VI)前后的氟磷灰石进行表征, 揭示了其相关去除机理。结果表明: 在温度为308 K, pH=3, 固液比为0.12 g/L, 平衡时间为120 min, 初始铀浓度为100 mg/L的条件下, 氟磷灰石对铀(VI)的吸附容量可达655.17 mg/g, 其吸附过程符合准二级动力学和Langmuir等温吸附模型, 且为自发和吸热过程。氟磷灰石对铀(VI)的去除机理为表面矿化, 吸附铀(VI)的氟磷灰石表面产生了新相准钙铀云母[Ca(UO₂)₂(PO₄)₂·6H₂O], 准钙铀云母在pH≥3水溶液中能保持较高稳定性。因此, 氟磷灰石可以作为一种有前景的矿化剂, 用于含铀废水的净化和固体化处理。     

C/W多层膜的制备及其光学特性

介绍了软X射线波段C/W多层膜的制备和光学性能检测.采用高真空直流磁控溅射方法在超光滑硅基片上制作了C/W多层膜,用X射线衍射(XRD)仪,小角测量方法测试多层膜的光学性能,采用透射电镜(TEM)观测多层膜断层样品的微观结构,并在同步辐射软X射线光束线上,测试了所制备的C/W多层膜样品的反射率,然后对测试结果进行拟合分析.结果表明,所制备的C/W多层膜样品的质量较高,界面清晰,粗糙度小,所有膜层均为无定形态,没有晶相生成,以44.2°入射在5.9 nm处有约6%的反射率.     

脉冲激光沉积制备SnS薄膜及其光学特性的研究

利用脉冲激光沉积法在玻璃衬底上制备SnS薄膜,研究了SnS薄膜的晶体结构、表面形貌以及有关光学特性。所制备的SnS薄膜样品为斜方晶系多晶结构,在(111)晶面上有很强的择优取向性;衬底温度在100~400℃范围内,表面形貌有所区别,随着温度升高,薄膜表面分别呈现大小晶粒共存、片状颗粒、针状颗粒和锥状颗粒的形貌特征;紫外区的SnS薄膜透过率极低,可见光范围的透过率很低,近红外区的透过率较大;样品在可见区和紫外区吸收强烈,吸收系数达105cm-1量级,直接禁带宽度为1.39~1.46 eV。