K_2ZnSiO_4∶Eu~(3+)红色荧光粉的制备及发光性能

采用高温固相法合成了适合近紫外光、蓝光激发的K2ZnSiO4∶Eu3+红色荧光粉,研究了该荧光粉的发光特性。XRD结果显示,所合成的荧光粉主晶相为K2ZnSiO4。样品的激发光谱由O2-→Eu3+电荷迁移带(200~350nm)和Eu3+离子的特征激发峰(350~500nm)组成,最强峰位于396nm,次强峰位于466nm。在396nm和466nm激发下,样品均呈多峰发射,分别由Eu3+离子的5D0→7FJ(J=0,1,2,3,4)能级跃迁产生,其中619nm处峰值最大。增加Eu3+离子的掺杂浓度,荧光粉的发光逐渐增强。在实验测定的浓度范围内,未出现浓度猝灭现象。不同Eu3+浓度样品的色坐标均位于色品图红光区,非常接近NTSC标准。     

The condition numbers for weighted Moore-Penrose inverse and weighted linear least squares problem

Condition numbers play an important role in numerical analysis. Classical normise condition numbers are used to measure the size of both input perturbations and output errors. In this paper, we study the weighted normwise relative condition numbers for the weighted Moore-Penrose inverse and the weighted linear least-squares (WLS) problems in the case of the full-column rank matrix. The bounds or formulas for the weighted condition numbers are presented. The obtained results can be viewed as extensions of the earlier works studied by others.     

简单芳香化合物的结构和性质对活性炭吸附行为的影响

用静态吸附法考察了一种活性炭对废水中四种简单芳香化合物的吸附行为,并用Langmuir模型对吸附数据进行了拟合。结果表明,Langmuir模型可以近似地描述这些芳香化合物在该活性炭上的吸附行为。芳香化合物的极性及其在水中的溶解度对其在活性炭上吸附的影响较大,芳香化合物与活性炭之间的π-π色散作用对吸附的影响很小。     

A highly selective chromo- and fluorogenic dual responding fluoride sensor: naked-eye detection of F- ion in natural water via a test paper

A highly selective and sensitive chromogenic and fluorogenic dual signal responding fluoride-sensor 1, comprising a Ru-bipy fluorophore (bipy = 2,2'-bipyridine) and a 2,4-dinitrophenylhydrazone chromophore was prepared and spectroscopically characterized. Uv-vis titrations with F- revealed the appearance of a new intense absorption band centered at about 580 nm which was accompanied by a dramatic change in color from yellow to magenta, with the association constant logK being 6.71 +/- 0.04. Fluorescence spectra showed that upon addition of F-, the emission intensities enhanced significantly without any change in the excited and emission wavelengths, suggesting a potential photoinduced electronic transfer (PET) signaling transduction mechanism. An easy-to-prepare test paper which was obtained by putting a filter paper into an acetonitrile solution of 1, can detect F- in aqueous media, indicating the potential application for detecting F- in natural aqueous environments without any spectroscopic instrumentation. Spectroscopic titrations of the free ligand were also studied for comparison.     

Antitumor activity of transition metal(II) complexes with all- trans retinoic acid

Five complexes of transition metals with all-trans retinoic acid (HRA) have been prepared and characterized by elemental analysis, molar conductance, t.g.–d.t.a, i.r., and u.v.-vis. spectroscopy, and 1H-n.m.r. spectrometry. The general formula of these complexes is ML2 ·nH2O where L=RA, M=MnII, CoII, NiII, CuII, ZnII, and n=3 or 4. They have been studied for their antitumour activity against human bladder cancer line EJ (EJ cells) with respect to proliferation, induce differentiation, P21 and mutation P53 expressions in vitro.     

聚氨酯/环氧树脂互穿网络硬质泡沫塑料反应过程和微观结构

聚氨酯／环氧树脂互穿网络(PU／EPIPN)硬泡中异氰酸根的消耗速度较纯PU硬泡高，是由于环氧树脂的固化荆同时也是异氰酸根反应的催化荆。而PU／EP IPN硬泡中环氧基的反应速度和反应程度均较纯EP网络低，归因于互穿网络对基团扩散的阻碍。在互穿网络硬泡形成过程中，存在环氧开环中所新产生的羟基与异氰酸根的反应、大分子多元醇中羟基与环氧基的反应以及异氰酸根与环氧基形成嗯唑烷酮的反应三种形成网络间的化学键的途径。同时由于PU／EPIPN硬泡高度的交联，使得IPN硬泡中两个网络具有良好的相容性。动态力学性能表明所有IPN样品都只有一个玻璃化温度。透射电镜表明IPN样品无明显的相界面。     

化学计量比LiNbO3晶体宏观生长缺陷的观察

本文对采用双坩埚提拉法(DCCZ)生长的化学计量比LiNbO3晶体中出现的机械双晶、组分过冷、包裹体等宏观生长缺陷进行了观察和分析.结果表明机械双晶通常以{102}和{104}面族为双晶面,而不是以前文献报道的{102}和{012}面族;化学计量比LiNbO3晶体双坩埚提拉法生长与同成份晶体生长不同,前者是助熔剂生长体系,生长速度稍快或温度较小的波动就会导致组分过冷,而后者属于纯熔体生长体系,不容易产生组分过冷;包裹体是由于组分过冷生长时界面失稳夹入熔体所造成的.由于这些缺陷的存在都会严重影响单晶的获得率和质量,为此,我们通过大量实验研究后提出了可以减少和避免这些生长缺陷提高晶体质量的方法.     

哑铃型富勒烯化合物的光诱导电子转移反应

1,3-Dipolar cycloaddition of DTE-azomethine ylides (DTE: dithienyl-ethene) to C60 in refluxed toluene was used to synthesize novel dumbbell-type fullerene dimer 1. For the sake of comparison, the monoadduct 2 were also synthesized. The molecular geometries of these two compounds were determined by theoretical calculations with HF-3/21G method. UV-Vis and fluorescence experiments were carried out in solvents with different polarity at the room temperature. All the results indicated the existence of a photoinduced intramolecular electron transfer process between the donor and acceptor moieties.     

示波极谱法测定葡萄籽提取物中原花青素

提出了测定葡萄籽提取物中原花青素的电化学分析新方法。在碱性硼砂底液中,原花青素与Zn(Ⅱ)在(-1.02±0.02V)(vs.SCE)电位处产生灵敏络合吸附波。其峰电流IP与原花青素在40～200mg·L-1范围内呈良好的线性关系,方法的检出限为25mg·L-1。该方法已用于保健食品中原花青素的含量测定,重现性好,结果满意。     

甲状腺肿大率与尿碘、盐碘关系的探讨

为了解甲状腺肿大率与尿碘“分离”现象产生的原因 ,用B超检查甲状腺肿大率 ,用酸消化砷 -铈接触法测定尿碘 ,用直接滴定法测定盐碘。结果表明 ,全市甲状腺肿大率为 7 1% ;尿碘中位数为 2 0 5 5 μg/L ,盐碘中位数为 43 4× 10 -6。甲状腺肿大率与尿碘水平无明显相关性 ,与盐碘浓度也无差异显著性。提示出现病情与尿碘分离现象 ,可能存在其它致甲肿的原因。