小分子硼酸肽的自组装

利用FMOC化学固相多肽合成法合成了3种含精氨酸的小分子硼酸肽(标记为BPs(1-3))。在生理pH下,含阳离子的硼酸肽可自组装形成有序超分子纳米组装体。二羟基酚染料茜素红与硼酸肽可特异性结合形成五元环硼酸酯,伴随荧光和颜色的显著变化,可进一步调控硼酸肽的自组装行为。通过扫描电镜研究茜素红调控前后硼酸肽的自组装形态,并用红外光谱和圆二色谱研究其自组装机理。结果表明,3种含精氨酸硼酸肽在生理pH下可自组装形成不同的超分子纳米组装体。通过茜素红的调控,茜素红/硼酸肽化合物,可自组装形成更有序,更精致的超分子聚集体。     

草酸盐共沉淀法制备SrAl_2O4∶Eu~(2+),Dy~(3+)发光粉体的研究

用草酸盐共沉淀法制备了SrAl2O4∶Eu2+,Dy3+发光粉体,用差热分析仪、X-射线衍射仪、扫描电镜和荧光分光光度计对制备产物进行了测试分析,并对烧成温度,Dy3+、H3BO3掺杂对荧光体发光特性的影响进行了讨论,确定了草酸盐共沉淀法的最佳烧成温度为1200℃,Dy3+最佳掺杂摩尔分数为0.002,硼酸为0.3。     

草酸盐共沉淀法制备SrAl2O4:Eu2+,Dy3+发光粉体的研究

用草酸盐共沉淀法制备了SrAl2O4:Eu2 ,Dy3 发光粉体,用差热分析仪、X-射线衍射仪、扫描电镜和荧光分光光度计对制备产物进行了测试分析,并对烧成温度,Dy3 、H3BO3掺杂对荧光体发光特性的影响进行了讨论,确定了草酸盐共沉淀法的最佳烧成温度为1200℃,Dy3 最佳掺杂摩尔分数为0.002,硼酸为0.3.     

前驱体法制备六方氮化硼颗粒及高温精制

以三聚氰胺和硼酸为原料,通过共沉淀法合成了二硼酸-三聚氰胺,在最佳工艺条件下以二硼酸-三聚氰胺为前驱体在氨气气氛中烧结制得六方氮化硼颗粒。采用IR、XRD、TG、SEM等测试方法对中间物和产物进行了表征,确定了中间物及产物的组成、物相、粒度及形貌。研究结果表明:以二硼酸-三聚氰胺为前驱体在1200℃烧结4h,可制得高纯度、晶型好的六方氮化硼。经过高温精制后的六方氮化硼颗粒具有较高的结晶度和致密度,其粒径可以达到20μm以上,纯度为98.5%。     

草酸盐共沉淀法制备SrAl2O4：Eu^2＋，Dy^3＋发光粉体的研究

用草酸盐共沉淀法制备了SrAl2O4：Eu^2＋，Dy^3＋发光粉体，用差热分析仪、X-射线衍射仪、扫描电镜和荧光分光光度计对制备产物进行了测试分析，并对烧成温度，Dy^3＋、H3BO3掺杂对荧光体发光特性的影响进行了讨论，确定了草酸盐共沉淀法的最佳烧成温度为1200℃，Dy^3＋最佳掺杂摩尔分数为0．002，硼酸为0．3。     

硼酸对Sr2Al6O11:Eu2+微波合成及荧光性质的影响

在微波场作用下合成了Sr2Al6O11:Eu2 x%(质量分数)(H3BO3)(x=0、1.5、3、5、7、9)系列蓝色光致发光材料.X射线粉末衍射(XRD)结果表明,未加硼酸作助熔剂时,产品的主相为SrAl2O4,硼酸在x=1.5～9之间产品的主相都为Sr2Al6O11.扫描电镜(SEM)观测结果:适量硼酸的加入有助于晶体的形成,硼酸的量为0时,产物为颗粒,硼酸量为x=1.5时,开始出现棒状晶体,当硼酸量为x=5时,产物主要为棒状晶体,当硼酸量x＞7时,产品明显团聚.荧光光谱显示:随硼酸量的增加,产品发光强度先增强后减弱,硼酸加入量为x=7,发光强度最高.Eu2 在Sr2Al6O11中存在两个发光中心,发射峰分别位于456.7nm(Eu2 1)和483.4nm(Eu2 2).当硼酸量＞7%(质量分数)时,发射峰红移,归因于硼酸对两种位置Eu2 的发光性能有不同的影响.     

X射线荧光光谱法在镁钙质耐火材料测定中的应用

采用熔融的方法进行制样,并以标准样品和高纯试剂配制熔融的系列标准玻璃片来建立校准曲线,采用灼烧后的样品与混合溶剂(四硼酸锂:偏硼酸锂=1:1)在高温条件下熔融成片,用X射线荧光光谱法测定镁钙质耐火材料中的SiO2、CaO、MgO、Fe2O3、Al2O3等组分含量,本方法分析的结果精密度和准确度高,分析速度快。     

X射线荧光光谱法测定冰晶石中6元素

应用X射线荧光光谱法测定了冰晶石中氟、钠、铝、硫、二氧化硅和氧化铁的含量。称取0．7000g样品与7．0000g混合熔剂（67g四硼酸锂与33g偏硼酸锂混合而成）于铂一金坩埚中混合均匀,加入几滴溴化锂脱模剂,置于电热熔融设备中熔融制得玻璃熔片用于X射线荧光光谱分析。采用本方法分析冰晶石标准样品,测量值与认定值吻合良好。     

新型Ce:YAG陶瓷荧光体封装白光LED的性能

利用真空烧结技术制备了一种可用于白光LED封装的Ce:YAG陶瓷荧光体。用X射线衍射仪、光致发光激发谱、光致发光谱等测试手段对这种陶瓷荧光体进行表征。结果表明:陶瓷荧光体的主相为Y3A l5O12,该荧光体可以很好的被470 nm蓝光激发,发射出550 nm的黄光。该陶瓷荧光体封装蓝光芯片所得的白光LED器件在110℃的高温下老化600小时,光衰只有10%,色坐标无变化,证明其寿命及稳定性远远好于采用传统方式封装的白光LED。研究结果表明,该Ce:YAG陶瓷荧光体是一种非常适合大功率白光LED封装的荧光材料。     

Eu^2＋，Dy^3＋掺杂铝酸锶长余辉发光材料的研究

用固相法制备出了Eu^2＋，Dy^3＋共掺杂Sr4Al7O25：Eu^2＋，Dy^3＋、SrAl2O4：Eu^2＋，Dy^3＋长余辉发光材料。研究了硼酸含量对其制备过程及发光性能的影响。用XRD对所合成材料进行物相分析，用荧光光谱仪记录其发射光谱，并在暗室里拍摄紫外激发下的发光照片。结果表明：随着硼酸加入量的不同，Eu^2＋、Dy^3＋共掺杂铝酸锶的发光效果、形貌特征均不同。在某一范围内，随着硼酸添加量的增加，材料的发光性能、发光亮度均有所提高，烧结温度有所降低。     

Preparation and luminescent properties of CaTiO<Subscript>3</Subscript>: Pr<Superscript>3+</Superscript>, Al<Superscript>3+</Superscript> persistent phosphors by nitrate-citric acid combustion method

Using citric acid as reducing agent and fuel, nitrate as a oxidant, boric acid as a flux material, red persistent phosphors CaTiO₃: Pr³⁺, Al³⁺ have been successfully synthesized by nitrate-citric acid combustion method. The best route is determined by studying influences of the amount of citric acid and ammonium nitrate, pH value of the solution, initiating temperature of furnace, and the amount of boric acid. The photoluminescence and crystallinity of persistent phosphors were investigated by using luminescence spectrometer and X-ray diffractometer (XRD), respectively. The results show that the optimum molar ratio of citric acid to calcium nitrate was about 0.8 and that of boric acid to calcium nitrate was about 0.4. Photoluminescence and decay curves show that the samples exhibited the optimal luminous properties at pH value of 6 and at the initiating temperature of 700 °C.     

Laser phosphoroscope and applications to room-temperature phosphorescence

A simple phosphoroscope with no moving parts is described. In one scan the total luminescence, the long-lived phosphorescence, and the short-lived fluorescence can be determined. A 50% duty cycle excitation from a diode laser is used to excite the sample, and from the digitized waveform the phosphorescence is extracted from the off period, the total emission from the full cycle, and the fluorescence from the on period corrected for the phosphorescence contribution. The performance of the system is demonstrated using room-temperature phosphorescence of organic dyes in boric acid glasses, a multi-emissive boron-polymer dye, and a europium chelate.     

纸浆纤维−聚碳酸酯复合材料

目的 采用可再生的纸浆纤维和功能塑料聚碳酸酯(PC)制备功能木塑复合材料，探究硼酸处理对复合材料相关性能的影响，进一步拓展材料在工程领域的应用。方法 配制质量分数为5%的硼酸溶液，将部分纸浆纤维放入硼酸溶液中浸渍2 h，将纸浆纤维与PC混合后，用双螺旋挤出机进行熔融加工，再用微型注塑机注塑成型,制备出复合材料。结果 经硼酸处理后的复合材料，在添加质量分数为30%的纸浆纤维时，复合材料的弹性模量达到4.31 GPa，比添加同样纤维含量的未经过硼酸处理的复合材料高16%:同时，与纯PC的弹性模量相比提高了90%。结论 采用硼酸处理可以提高纸浆纤维的热稳定性，可进一步提高复合材料的力学强度。PC是一种生活中常见的功能塑料，其本身具有优良的力学性能，硼酸的处理和纸浆纤维的加入使其力学性能进一步提升，有望作为结构材料应用于集装箱、托盘等方面，在包装领域有较好的应用前景。     

琼脂产品中硼酸含量的探讨

根据国家标准GB/T21918-2008食品中硼酸的测定[1]中第一法测定各类食品中的硼酸,特别是琼脂产品中的硼酸。数据结果表明,硼酸在琼脂产品中的含量值得探究。     

Doping boric acid into polyacrylonitrile fibers prior to drying process and the effects on stabilization

The effects of boric acid on the stabilization reactions of polyacrylonitrile (PAN) fibers were investigated by dipping fibers in boric acid aqueous solutions prior to drying process. The boron (B) contents in the PAN fibers are proportional to the concentrations of bath solution up to 2300 ppm when the boric acid concentration is 2.0 wt%. Methylene blue adsorption capacities of the doped PAN fibers decrease with increasing B. Differential scanning calorimetry spectra of the PAN fibers show the boric acid has a weak inhibition effect on the cyclization reactions and a significant hindering effect on the oxidation reactions. Combing with the elemental analysis and bulk densities of the stabilized fibers, it is considered that boric acid particles prevent oxygen from diffusing by occupying the space of the pores. However, by prolonging the stabilization period, the oxygen content in stabilized B-doped PAN fibers can be regulated to an appropriate value, and thus, carbon fibers owning excellent mechanical properties can be prepared. The B content in the resultant carbon fibers is nearly doubled compared to that of the relative PAN fibers.     

硼酸涂覆法防止C-Cu复合丝氧化问题

以硼酸为保护剂, 通过在C-Cu复合丝表面涂覆一层硼酸试剂, 有效地解决了高温复合时镀铜层的氧化难题, 并通过XRD、 SEM和拉伸强度测试全面考察了硼酸的影响。实验结果表明, 硼酸的浓度为1.0%时铜镀层的氧化程度很小, 炭纤维在复合材料中分散均匀且与基体铝结合良好, 1.0%的硼酸用量对复合材料的力学性能没有任何影响。      

光亮硫酸盐镀锌液中硼酸的测定

光亮硫酸盐镀液中硼酸的测定，一般采用氯化钾镀锌体系中对硼酸的测定方法，但误差较大，现略加改进，其准确性就有了较大的提高，而且操作简便，快捷，可以满足生产要求，本法也适应用于氯化钾体系测定硼酸含量。     

碳热还原法制备部分石墨化的C/B_4C复合粉体

以炭黑和硼酸为原料,通过碳热还原法合成了部分石墨化的C/B4C复合粉体。考察了加热温度和硼酸添加量对C/B4C复合粉体合成过程的影响,采用X射线衍射和扫描电镜等方法对C/B4C复合粉体的物相及形貌进行了分析,利用热重法研究了C/B4C复合粉体的氧化性能。研究结果表明,随着加热温度的升高,复合粉体的石墨化度增大,B4C含量下降;随着硼酸加入量的增大,复合粉体中B4C含量及其石墨化度均增大;当炭黑和硼酸加入量分别为33.21%和66.79%时,经1900℃热处理所得复合粉体的石墨化度达23.26%,B4C含量为20.63%;与工业用B4C和炭黑的混合物相比,实验室合成的C/B4C复合粉体具有较好的抗氧化性能。     

Low-valence ion addition induced more compact passive films on nickel-copper nano-coatings

Ni-Cu nano-coatings were prepared by pulsed electroplating technique in the baths containing various amount of boric acid. Their microstructure, morphologies and corrosion resistance were characterized in detail. The addition of boric acid strongly influences on the microstructure of the Ni-Cu coatings. The coating with a grain size of 130 nm, obtained from the bath containing 35 g L⁻¹ boric acid, shows the highest corrosion resistance. This is attributed to the low-valence Cu ion (Cu⁺) additions in nickel oxide, which could significantly decrease the oxygen ion vacancy density in the passive film to form a more compact passive film. The higher Cu⁺ additions and the lower diffusivity of point defects (D₀) are responsible for the formation of more compact passive film on the coating obtained from the bath with 35 g L⁻¹ boric acid.     

Homogeneous dispersion of gallium nitride nanoparticles in a boron nitride matrix by nitridation with urea

A Gallium Nitride (GaN) dispersed boron nitride (BN) nanocomposite powder was synthesized by heating a mixture of gallium nitrate, boric acid, and urea in a hydrogen atmosphere. Before heat treatment, crystalline phases of urea, boric acid, and gallium nitrate were recognized, but an amorphous material was produced by heat treatment at 400 degrees C, and then was transformed into GaN and turbostratic BN (t-BN) by further heat treatment at 800 degrees C. TEM obsevations of this composite powder revealed that single nanosized GaN particles were homogeneously dispersed in a BN matrix. Homogeneous dispersion of GaN nanoparticles was thought to be attained by simultaneously nitriding gallium nitrate and boric acid to GaN and BN with urea.