硅基pH荧光纳米颗粒的制备及其光学性能研究

荧光素钠的分子内运动会受到刚性无机材料的限制，阻塞非辐射弛豫通道，使放射性衰变填充到基态，提高其发光性能。利用st9ber法制备了pH响应荧光纳米颗粒。红外分析结果表明，荧光素钠与二氧化硅有效复合。探讨了荧光纳米颗粒的紫外光谱和荧光光谱与溶液pH值的响应关系。在pH值为1～3时，430 nm处紫外吸收强度随pH值增加逐渐降低，在pH值为4～11时，424到484 nm间紫外吸光强度随pH值增加逐渐增加，520 nm时线性良好；而在pH值为4～9之间，荧光强度随pH值增加而升高，并具有较好的响应关系。对荧光纳米颗粒分别在pH值为5和10的缓冲溶液中的荧光光谱进行了干扰测试，几乎不受常见离子干扰，具有良好抗干扰能力。     

纳米ZnO溶胶的制备及其光学性能

以氯化锌和氢氧化钠为原料,采用多元醇法制备纳米ZnO溶胶。利用透射电镜、荧光光谱和紫外光谱对其进行表征,详细研究了水浴时间和pH值对纳米氧化锌形貌和光学性能的影响。结果表明:随着水浴处理时间的增长,纳米ZnO粒径有所增大,其紫外吸收光谱红移,紫外荧光增强,而黄-绿光荧光强度减弱。随着pH值的增大,纳米ZnO粒子的粒径逐渐减小,紫外吸收光谱蓝移,其紫外荧光逐渐增强。     

助剂对紫外荧光喷墨油墨发光性能的影响

为了获得衰减不明显的高荧光强度的紫外荧光喷墨油墨,选用乙醇和三乙醇胺分别作为干燥剂和pH 值调节剂,配制油墨样品,探讨了乙醇和三乙醇胺含量对荧光强度的影响;选用不同种类及含量的紫外吸收剂,分别制备油墨样品,探讨了紫外吸收剂种类和含量对荧光强度、荧光衰减的影响。结果表明,随着乙醇含量的增加,三乙醇胺含量的降低,荧光强度显著增强;紫外吸收剂UV-7292 对荧光强度影响较小,且能改善油墨的耐光性能。在满足其它性能的前提下,当乙醇、三乙醇胺和紫外吸收剂UV-7292 的质量分数分别为15%,0. 6%和0. 5%时,紫外荧光喷墨油墨发光性能最佳。     

高荧光量子产率的二硫化钼量子点制备及荧光性能研究

二硫化钼量子点(MoS2 QDs)具有优良物理、化学等特性,在催化、荧光成像和荧光传感及生物成像等方面具有潜在的应用前景,然而其制备方法及量子产率仍有改进空间.本工作以钼酸钠提供钼源,谷胱甘肽提供硫源,通过"自下而上"一步水热法制备MoS2 QDs,并以其荧光强度作为指标,采用单因素分析,优化MoS2 QDs制备条件中的钼源与硫源比例、pH值、反应时间、反应温度.结果表明,最佳钼源与硫源质量比例为1:3.5、最佳pH值为4?8之间、反应时间18 h、反应温度210℃.采用正交试验的方法,优化出MoS2 QDs的最佳制备条件为:反应时间30 h、反应温度220℃、钼源与硫源比例为1:3.5、pH值为3,荧光量子产率高达21％.所制备MoS2 QDs的粒径4.0±0.35 nm,且单分散,富含氨基和羧基官能团,紫外吸收峰336 nm;发射波长为424 nm;半峰宽79 nm.可为MoS2 QDs在高灵敏的离子、生物分子检测以及低毒的细胞成像打下基础.     

紫外LED辅助的4H-SiC化学机械抛光

在4H-SiC晶片的化学机械抛光(CMP)体系中加入紫外LED系统,研究TiO_2颗粒、紫外LED光功率、抛光温度和抛光液pH值对4H-SiC晶片抛光性能的影响规律,以获得较高的材料去除速率(MRR)和原子级光滑表面,满足LED器件对衬底材料表面的严格要求.结果表明,采用平均粒径25 nm、质量分数为2%的TiO_2颗粒,可显著提高MRR,且减少微划痕等表面缺陷;增大紫外LED功率,MRR随之增大;升高抛光温度,MRR快速提高,并可降低抛光所得表面粗糙度;在CMP体系中加入紫外体系可增加羟基自由基数量,抛光液pH值较低(2.2)也可维持较高MRR值,且抛光液pH值超过10时MRR值大幅提高.采用原子力显微镜(AFM)、光学显微镜来考察4H-SiC晶片抛光后的表面质量.基于各因素的影响规律,最终获得表面粗糙度为0.058 6 nm的4H-SiC晶片表面,且MRR达到352.8 nm/h.     

水性聚氨酯-分散荧光黄高分子荧光染料的合成与荧光特性

用聚氧化丙烯二醇、2,4-甲苯二异氰酸酯、二羟甲基丙酸、三乙胺和分散荧光黄(DFY)合成了一种新型的水性聚氨酯-分散荧光黄(PU-DFY)高分子荧光染料.红外和紫外-可见吸收光谱显示,DFY已被化学键入聚氨酯链中.荧光光谱表明,PU-DFY和DFY都可在507nm处发出较强荧光,且很低浓度PU-DFY发出的荧光都较高浓度DFY的强.研究还发现,加入二苯胺猝灭剂的PU-DFY,荧光强度随温度的升高而增强,与一般荧光物质荧光强度的温度特性相反.     

pH值对高荧光性能CMC/Eu复合纳米材料粒径及其分布的影响

令可生物降解的羧甲基纤维素(CMC)和Eu3+在微波加热条件下反应,制备CMC/Eu纳米复合材料。用FT-IR、SEM、AFM、荧光光谱表征其结构、表面形貌和发光性质,并探讨pH值对其粒径大小及分布的影响。结果显示,在实验条件下纳米化后,其荧光强度大幅度提高;粒径在150～500nm范围内;pH值增大,粒径变小,分布均匀;pH值=13.4时粒径最小,分布最均。     

温度和pH敏感的磷酸腺苷荧光共聚物传感器

合成了一种新的疏水单体N-丙烯基-N'-α-喹啉硫脲(AQT)及其与N-异丙基丙烯酰胺、N,N-二甲基丙烯酰酰胺的三元共聚物.研究了在不同pH值条件下,聚合物水溶液的荧光响应特性,结果表明随着pH值的升高,聚合物水溶液的荧光强度下降.聚合物水溶液表现出显著的温度敏感特性,且通过控制聚合单体的比例,可以在32.5～37.5℃范围内调节聚合物的最低临界溶液温度(LCST).在聚合物溶液中,ATP、ADP和AMP的滴定实验表明,聚合物对ATP表现出良好的响应特性,而对ADP和AMP则几乎没有响应,可望应用于生理环境中ATP的测定.     

改性花青素涂覆聚丙烯新鲜度指示膜的制备与研究

以乙酸为酰化剂对玫瑰茄花青素改性处理制得新鲜度指示剂,选用聚乙烯醇(PVA)为基液,与改性花青素共混制得新鲜度指示液,以聚丙烯(PP)为基膜采用旋涂法制备食品新鲜度指示膜。对改性花青素进行红外光谱及紫外-可见光光谱分析,对指示膜pH响应性、热稳定性和光照稳定性进行了研究。结果表明,红外光谱显示玫瑰茄花青素成功引入酰基;紫外-可见光谱显示改性后的花青素溶液在可见光区域最大吸收峰下的吸光度突变区间由pH值2～3迁移到pH值3～4;指示膜pH响应测试显示随着pH值升高指示膜由红变浅粉再变绿;所制备改性花青素指示膜在光照和不同温度下的颜色稳定性均高于未改性花青素指示膜。     

紫外荧光双马树脂基复合材料的制备及性能

紫外荧光树脂基复合材料可用于航空航天大型复合材料制件牺牲层的制备,减少装配中垫片的使用,并通过牺牲层的荧光显色避免切削时伤及本体铺层.采用热熔法制备了紫外荧光双马树脂及国产T700碳纤维机织物/紫外荧光双马树脂预浸料,采用热压罐法制备了国产T700/紫外荧光双马树脂复合材料.系统研究了未添加紫外荧光粉、添加1.8％含量...     

UV-light induced photodegradation of 17alpha-ethynylestradiol in aqueous solutions

The photodegradation of 17alpha-ethynylestradiol (EE2) in aqueous solutions induced by UV-light was preliminarily studied in this paper by means of fluorescence, UV and infrared spectra. The result suggested that EE2 in aqueous solutions underwent photodegradation under irradiation with UV disinfection lamp (lambda = 254 nm, 30 W), but the photodegradation was not observed under high pressure mercury lamp (lambda > or = 365 nm, 250 W). The photodegradation of 1.6-20.0 mg/l EE2 in aqueous solutions at a given initial pH value of 6.8 was pseudo-first order reaction. Increasing the initial concentration of EE2 lowered the photodegradation rate. The photodegradation rate of EE2 reached the lowest value at pH about 5.0, higher pH values of 6.0-8.0 benefited the photodegradation. Ferric ions can promote the photodegradation of EE2 in aqueous solutions at pH value of 2.0-5.0.     

具有UV探测灵敏性、稳定性和重复利用性的层状铀酰配位聚合物研究

灵敏的UV探测对于工业生产和个人防护非常重要, 本研究旨在开发新型UV探测材料。一般而言, 铀酰单元具有相对高的UV吸收效率和荧光强度。本课题组成功地在水热条件下制备了一例铀酰配位聚合物[(TEA)₂(UO₂)₅(PhPC)₆] (TEA = 四乙基胺离子, PhPC = (2-羧基乙基)苯膦酸, 标记为UPhPC-1)。基于单晶XRD数据的结构分析表明UPhPC-1中有三个不同的铀酰中心, 其中两个铀酰单元为五角双锥构型, 而第三个铀酰单元为四角双锥构型。全部三个铀酰中心与配体在[bc]平面配位形成无限的铀酰层。通过氢键网格和π-π相互作用, 这些铀酰层堆积成整体的层状结构。此化合物具有很好的热稳定性、水稳定性和高抗辐照能力。UV辐照实验结果表明UPhPC-1的本征荧光强度对365 nm的UV辐射高度敏感, 检测下限低且响应速率快, 而发光强度与UV辐照剂量呈负相关。电子顺磁共振谱分析证实在UV光照射下, UPhPC-1中极有可能产生自由基, 造成铀酰荧光部分淬灭。进一步, 被淬灭样品中的自由基能够在加热后被去除, 从而实现UPhPC-1发光强度的快捷恢复。目前的结果表明UPhPC-1在UV辐照的定量探测领域具有一定的发展潜力。     

Detection of nonderivatized peptides in capillary electrophoresis using quenched phosphorescence.

A capillary electrophoresis detection technique for (small) peptides is presented, i.e. quenched phosphorescence, a method that is generally applicable and does not require chemical derivatization. For this purpose, a novel phosphorophore, 1-bromo-4-naphthalenesulfonic acid (BrNS), was synthesized. BrNS has sufficient water solubility and provides strong phosphorescence at room temperature over a wide pH range. The detection is based on the dynamic quenching of the BrNS phosphorescence background signal by electron transfer from the amino group of the peptides at pH 9.5-10. For the di- and tripeptides Val-Tyr-Val, Val-Gly-Gly, Ala-Ser, Gly-Asn, Gly-Ala, and Gly-Tyr, detection limits in the range of 5-20 microg/L were obtained. The novel technique is even a good alternative for the (limited) group of peptides containing tyrosine and, thus, exhibiting native fluorescence as well as strong UV absorption: using Gly-Tyr, Val-Tyr-Val, methionine enkephalin, and human angiotensin II as test compounds, quenched phosphorescence detection was found to compare favorably with absorption detection at 190- and 266-nm laser-induced fluorescence detection, as performed with a recently developed, small-size, quadrupled Nd:YAG laser.     

High-throughput liquid chromatography/mass spectrometry method for the determination of the chromatographic hydrophobicity index

A fast gradient reversed-phase liquid chromatography (LC) method, using an acetonitrile gradient was developed to determine the chromatographic hydrophobicity index (CHI), as reported by Valco et al. (Anal. Chem. 1997, 69, 2022-2029).The analytical method provides retention times, based on UV detection at two different wavelengths, which then are converted into CHI values after calibration with a set of test compounds. The CHI of each compound is measured at three different pH values, 2.0, 7.4, and 10.5; so using an 8-min gradient at each pH value one compound can be analyzed in approximately 24 min. The aim of this work is to improve the throughput of the CHI screening using a LC/MS approach, so the application of the LC/MS technique is an extension of the LC/UV approach previously reported by Valco et al. This approach allows contemporary injection of N compounds into the LC/MS system, the retention time of each compound can be then extracted from the selected ion recording chromatograms. The throughput of the existing screening method could be increased by N times, where N is the number of compounds injected, so only three runs are needed to determine the CHI at three different pH values for a set of N compounds. The highest value of N depends on the total number of channels that can be monitored simultaneously; in the present work, 32 channels were used. This LC/MS method has been tested for a number of commercial products analyzed as mixtures, and data obtained were compared with those coming from the classical LC/UV approach. In the same way, the method was tested for a number of compounds associated with two GlaxoWellcome projects in the antibacterial area. Data reported show that the LC/MS method can be successfully applied for analyzing compounds in mixtures and for compounds with poor UW absorption, which cannot be analyzed with the standard LC/UV method.     

The decolorization and mineralization of acid orange 6 azo dye in aqueous solution by advanced oxidation processes: a comparative study

The comparison of different advanced oxidation processes (AOPs), i.e. ultraviolet (UV)/TiO(2), O(3), O(3)/UV, O(3)/UV/TiO(2), Fenton and electrocoagulation (EC), is of interest to determine the best removal performance for the destruction of the target compound in an Acid Orange 6 (AO6) solution, exploring the most efficient experimental conditions as well; on the other hand, the results may provide baseline information of the combination of different AOPs in treating industrial wastewater. The following conclusions can be drawn: (1) in the effects of individual and combined ozonation and photocatalytic UV irradiation, both O(3)/UV and O(3)/UV/TiO(2) processes exhibit remarkable TOC removal capability that can achieve a 65% removal efficiency at pH 7 and O(3) dose=45mg/L; (2) the optimum pH and ratio of [H(2)O(2)]/[Fe(2+)] found for the Fenton process, are pH 4 and [H(2)O(2)]/[Fe(2+)]=6.58. The optimum [H(2)O(2)] and [Fe(2+)] under the same HF value are 58.82 and 8.93mM, respectively; (3) the optimum applied voltage found in the EC experiment is 80V, and the initial pH will affect the AO6 and TOC removal rates in that acidic conditions may be favorable for a higher removal rate; (4) the AO6 decolorization rate ranking was obtained in the order of O(3)相似文献   

复合纳滤膜凝胶功能层的聚电解质特性

通过界面聚合的方法制备了以聚甲基丙烯酸二甲氨基乙酯(PDMAEMA)为交联预聚体,以微孔聚砜膜为基膜的复合纳滤膜;研究了凝胶表层的聚电解质特性.实验表明:荷电纳滤膜的表面具有一定的疏水性.交联凝胶层的溶胀度表现出pH、外加盐浓度、温度的响应性.     

Degradation of n-butyl benzyl phthalate using TiO2/UV

n-Butyl benzyl phthalate (BBP) has been classified as endocrine disrupting compound and priority pollutant. Effects of TiO(2) dosage, pH, initial BBP concentration and co-existing substances on the degradation of BBP by TiO(2)/UV process were investigated. The optimal TiO(2) dosage and pH value for the BBP degradation were 2.0gL(-1) and 7.0, respectively. The degradation rate of BBP by TiO(2)/UV process could be fitted pseudo-first-order kinetics. The effects of co-existing substances on the degradation rate of BBP revealed that some anions (such as BrO(3)(-), ClO(4)(-) and Cr(2)O(7)(2-)) could enhance BBP degradation, and other anions would restrain BBP degradation. The sequence of inhibition was PO(4)(3-)>CO(3)(2-)>NO(3)(-)>SO(4)(2-)>Cl(-). The cations K(+), Na(+), Mg(2+) and Ca(2+) had the restrained effect on the BBP degradation, and the effect of Ca(2+) was the strongest among four cations tested. The organic compounds acetone and methanol decreased the degradation rate of BBP. The major intermediates of BBP degradation were identified as mono-butyl phthalate, mono-benzyl phthalate and phthalic acid, and a primary degradation mechanism was proposed.     

聚砜纳滤中空纤维膜去除内分泌干扰物双酚A

由本实验室自制等离子体改性聚砜纳滤中空纤维膜对内分泌干扰物双酚A溶液进行截留,通过改变溶液浓度、pH、操作压力以及离子强度等因素,经过长时间截留,观察聚砜纳滤中空纤维膜对双酚A溶液的截留率以及通量的变化,分析其作用机理,归纳出改变不同因素使得截留率及通量变化的规律,并研究了不同条件下原液浓度的变化.实验结果表明,聚砜纳滤中空纤维膜对双酚A有很强的吸附作用力,这种吸附力为去除双酚A的主要机理,且溶液为较高浓度,pH=6,压力为0.2MPa,低离子强度时去除率达到90%以上.在近中性条件下,吸附作用力在聚砜纳滤中空纤维膜去除双酚A过程中起主导作用,在较高pH条件下静电斥力发挥作用,离子强度的大小对吸附作用力影响不大.     

光固化EA体系中Eu(TTA)(AA)2Phen配合物的原位法合成及荧光性能

利用“原住法”合成技术，在EA(双酚A环氧丙烯酸酯树脂)中，合成了稀土荧光配合物Eu(TTA)(AA)2Phen(TTA：噻吩甲酰基三氟丙酮；AA：丙烯酸；Phen：邻菲咯啉)，利用红外光谱、紫外一可见光谱和荧光光谱对体系进行了表征。红外光谱的研究表明，配合物在EA体系中的特征吸收峰被基质树脂所掩盖，主要表现为基质树脂的特征吸收；紫外一可见光谱的研究表明，该体系在350nm附近出现配体TTA的强特征吸收，在低于300nm时，吸收峰被基质树脂掩盖；荧光光谱的研究表明，配合物在EA体系中能发出强的铕离子的特征荧光．并且低于铕质量分数为0．4％的范围内，荧光强度与稀土离子含量接近线性关系。     

Synthesis and non linear optical properties of new inorganic–organic hybrid material: 4-Benzylpiperidinium sulfate monohydrate

Single crystals of 4-benzyl-piperidine sulfate monohydrate were grown by slow evaporation method at room temperature. The synthesized compound was characterized by means of single-crystal X-ray diffraction, FT-IR and Raman spectroscopy, UV–visible and photoluminescence studies. The title compound crystallises at room temperature in the non centrosymmetric space group P2₁2₁2₁.The recorded UV–visible spectrum show good transparency in the visible region and indicates a non-zero value of the first Hyperpolarizability. Photoluminescence spectrum shows a broad and intense band at 440 nm and indicates that the crystal emits blue fluorescence. We also report DFT calculations of the electric dipole moments (μ), Polarizability (α), the static first Hyperpolarizability (β) and HOMO–LUMO analysis of the title compound was theoretically investigated by GAUSSIAN 03 package. The calculated static first Hyperpolarizability is equal to 6.4022 × 10⁻³¹ esu. The results show that 4-benzyl-piperidine sulfate monohydrate crystal might have important non linear optical behavior and can be a potential non linear optical material of interest.