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1.
设计合成了带有羟基取代的希夫碱配体化合物1,并研究了它与Zn2+的识别。结果发现:在乙腈溶剂中化合物1与Zn2+络合后有强的荧光发射,而化合物1除了与Mg2+络合后有弱的荧光发射被检测到外,与其他离子(Fe2+, Co2+, Ni2+, Cu2+, Cd2+, Hg2+, Pb2+, Ca2+, Ba2+, Sr2+)络合后未检测到荧光发射。研究结果还表明:化合物1能在多组分混合离子中对Zn2+进行选择性检测而不受其他离子的干扰。为了弄清配体化合物1与Zn2+络合的反应机理,本论文还设计合成了其他三个带羟基取代的希夫碱配体化合物2-4,并分别研究了它们与Zn2+的识别。  相似文献   

2.
设计合成基于苯并噻唑Zn2+荧光增强型探针BHP,在HEPES缓冲液中测其对Zn2+识别性能。实验结果表明,BHP对Zn2+有较高的选择性,对其他金属离子如Cd2+,Fe2+,Ni2+,Pb2+,Hg2+,Al3+,Mn2+,Ag+,Cu2+,Co2+,Na+,K+,Mg2+和Ca2+无明显荧光增强响应。BHP与Zn2+按1:1计量比配位,在生理条件下荧光强度不受pH值影响。在HeLa细胞中对Zn2+的造影表明BHP可用于生物体Zn2+检测。  相似文献   

3.
SrAl12O19:Mn4+是一种用于高显色性白光发光二极管的候选红色荧光材料。本论文研究了Mg2+、Zn2+和Ge4+离子的掺杂效应以及Ge3+、Ca2+和Ba2+离子的取代效应SrAl12O19:Mn4+荧光材料性能的影响。样品通过高温固相反应制备,焙烧温度在1 250~ 1 500℃之间。利用X射线衍射技术表征了材料的相纯度,用荧光激发光谱和发射光谱表征了材料的荧光性能。研究结果指出,与未进行Mg2+或Zn2+掺杂的样品相比,Mg2+或Zn2+离子对Al3+格位的掺杂可以使材料的发光强度提高~60%,其原因被认为是掺杂促进了激活剂Mn4+离子进入晶格,其过程可以表示为:MO+MnO2=MAl''+MnAl·+3OO×(M=Mg,Zn),电子顺磁共振谱支持这一结果。Ge4+离子的掺杂使材料的发光性能明显下降。Ge3+离子可以取代Al3+离子形成全范围的固溶体,其中少量Ge3+离子的掺杂可以使材料的荧光发射强度提高~13%,而掺杂量进一步提高使材料的荧光性能下降。Ca2+和Ba2+对Sr2+的取代仅形成有限范围的固溶体。Ca2+的取代使材料的发光性能提高;而 Ba2+的取代使材料的发光强度下降。  相似文献   

4.
采用水溶液离子交换法制备了Ca2+交换的4A,13X和LSX分子筛,并在25 ℃下测定了它们的静态吸附等温线和动态穿透曲线.研究发现, Ca2+交换的4A,13X和LSX分子筛对氮的吸附性能都明显优于其相应的钠型分子筛,而它们对氩的吸附量变化不大,说明Ca2+交换的这三种分子筛是较好的氮氩分离吸附剂.从动态吸附的结果来看,所研究的各种分子筛都有一个最优的吸附分离压力,在本论文研究的压力范围内,这个最优压力在0.6 MPa附近.由穿透曲线可推算出混合气体的吸附量,通过氮和氩在混合气体中的吸附量和相应纯气体吸附量的对比可以得出,对于氮氩吸附选择性较高的分子筛,氮的存在对氩的吸附量有较大的影响.  相似文献   

5.
采用B3LYP/6-31++G(d,p)方法,对内含式化合物X@(HBNH)12 (X = Li0/+, Na0/+, K0/+, Be0/2+, Mg0/2+, Ca0/2+, H和He)的不同对称性构型进行计算,讨论其最稳定构型的几何参数、包含能、平衡常数、自然电荷、自旋密度、电离势和HOMO-LUMO能隙。发现在X@(HBNH)12化合物中,客体Na0/+, K0/+, Mg0/2+, Ca0/2+, H和He几乎处在笼的中心,Li+处在中心附近0.021 nm的半径内,Li和Be0/2+很大程度上偏离笼的中心位置。Li+, Be2+, Mg2+和Ca2+与其它离子相比,更易嵌入笼内形成稳定的内含式化合物。而且,M@(HBNH)12 (M = Li, Na,K)的第一电离势比Cs(3.9 eV)原子小,是超碱金属。  相似文献   

6.
关莉莉  段连运  谢有畅 《化学学报》2004,62(15):1392-1396,FJ02
采用水溶液离子交换法分别制备了不同Li^ 和Ca^2^ 交换度的A型分子筛,并在25℃下测定了各分子筛吸附剂的氮和氩的吸附等温线及穿透曲线.研究发现,锂交换和钙交换的两种分子筛的氮吸附量和氮氩分离选择性都随分子筛中阳离子交换度的增加而增大;在阳离子交换度较高时,锂离子和钙离子交换的A型分子筛的氮氩分离能力均优于NaA分子筛.穿透曲线的结果显示,所研究的各种吸附剂都存在一个最优的吸附分离压力,大约在0.6MPa.在0.6MPaT,接近100%阳离子交换度的CaNaA分子筛的动态氮氩分离性能优于相同交换度的LiNaA分子筛。  相似文献   

7.
Ca2+交换的几种分子筛的氮氩分离性能   总被引:1,自引:0,他引:1  
采用水溶液离子交换法制备了Ca2+交换的4A、13X和LSX分子筛,并在25 ℃下测定了它们的静态吸附等温线和动态穿透曲线.研究发现, Ca2+交换的4A、13X和LSX分子筛对氮的吸附性能都明显优于其相应的钠型分子筛,而它们对氩的吸附量变化不大,说明Ca2+交换的这三种分子筛是较好的氮氩分离吸附剂.从动态吸附的结果来看,所研究的各种分子筛都有一个最优的吸附分离压力,在本论文研究的压力范围内,这个最优压力在0.6 MPa附近.由穿透曲线可推算出混合气体的吸附量,通过氮和氩在混合气体中的吸附量和相应纯气体吸附量的对比可以得出,对于氮氩吸附选择性较高的分子筛,氮的存在对氩的吸附量有较大的影响.  相似文献   

8.
合成了以1,8-萘酰亚胺为发色团,以联吡啶为离子受体的Zn2+荧光探针,并进行了表征及离子识别性能的研究。研究表明该化合物对Zn2+具有良好的识别性能,同时相对于Ca2+, Cd2+, Co2+, Cu2+, Hg2+, Fe3+, Mn2+, Ni2+, Pb2+等金属离子具有良好的选择性。  相似文献   

9.
采用水溶液离子交换法制备了高Li+交换度的4A、13X和LSX分子筛,并在25 ℃下测定了它们的静态吸附等温线和动态穿透曲线.研究发现,高Li+离子交换度的4A、13X和LSX分子筛都具有较大的氮吸附容量和较高的氮氩分离选择性,说明高Li+离子交换度的4A、13X和LSX分子筛是较好的氮氩分离吸附剂.从动态穿透曲线结果来看,所研究的三种分子筛都有一个最优的吸附分离压力,在本文研究的压力范围内,这个最优压力在0.6 MPa附近.对比高锂交换度的三种分子筛,以高锂交换度的LSX分子筛的氮氩吸附分离性能最好.  相似文献   

10.
研究了复合物Mg-NCSCH3在230~440 nm波段和Ca-NCSCH3在320~560 nm波段的光解离光谱. 复合物Mg-NCSCH3, Ca-NCSCH3光诱导反应的产物质谱表明有非反应猝灭产物Mg(Ca), C—S键断裂产物Mg(Ca)NC 和Mg(Ca)NCS以及重排反应产物Mg(Ca)-CHSH通道. 在原子跃迁谱线(32S→32P, 对于Mg; 42S?42P, 对于Ca)的红和蓝两边, Mg-NCSCH3的光解离光谱由两个宽峰组成; 而对于Ca-NCSCH3, 则是由三个谱峰构成. CIS/6-311++G**等级上, 对应于基态构型的Mg-NCSCH3电子态跃迁能量和振子强度与实验光谱较为一致; 而Ca-NCSCH3有较大的差别. 这是因为CIS方法忽略电子相关效应, 而Ca-based的跃迁中3d和4s轨道间存在较强的混合所致.  相似文献   

11.
一些具有NASICON型网格结构的固体电解质具有高的电导率和好的稳定性,NASICON的意思是Na Super Ionic Conductor[1]。当NaZr2(PO4)3中P5 被Si4 部分取代时便可以得到具有NASICON结构的Na1 xZr2SixP3-xO12体系,其具有高的钠离子电导率。然而有相同结构的Li1 xZr2SixP3-xO12体系的离子电导率却很低,这是因为Li 半径太小,而NASICON三维网格结构的离子通道太大,两者不匹配而使电导率下降[2]。但当LiZr2(PO4)3中Zr4 被离子半径小些的Ti4 取代,所得LiTi2(PO4)3的通道就与Li 半径相匹配,适合于锂离子的迁移,从而使其电导率…  相似文献   

12.
采用传统固相反应工艺,按化学计量比合成BaO-Al_2O3-SiO_2(BAS)-x%(w/w) Li_2O-Na_2O-B_2O3-SiO_2(LNBS)(x=0,1,2,3,4)陶瓷。研究不同LNBS烧结助剂添加量对BAS系微波介质陶瓷的结构和介电性能的影响。通过Clausius-Mossotti公式计算讨论了BAS理论与实验介电常数(εr)的差异。研究结果表明:LNBS烧结助剂中Li+进入钡长石Al3+位或单四元环(S4R)间隙,并产生了O_2-空位或Ba2+空位,从而促进BAS六方相向单斜相的转变。添加适量的LNBS烧结助剂后,BAS陶瓷的烧结温度从1 400℃降低到1 325℃,同时BAS陶瓷样品密度、品质因数(Qf)值以及频率温度系数(τf)得到改善。当x=1,烧结温度为1 325℃时,可获得综合性能相对较好的BAS陶瓷,其介电性能:Qf=35 199 GHz,εr=6.37,τf=-1.613×10-5℃-1。  相似文献   

13.
Thin crystals of La2O3, LaAlO3, La2/3TiO3, La2TiO5, and La2Ti2O7 have been irradiated in situ using 1 MeV Kr2+ ions at the Intermediate Voltage Electron Microscope-Tandem User Facility (IVEM-Tandem), Argonne National Laboratory (ANL). We observed that La2O3 remained crystalline to a fluence greater than 3.1×1016 ions cm−2 at a temperature of 50 K. The four binary oxide compounds in the two systems were observed through the crystalline-amorphous transition as a function of ion fluence and temperature. Results from the ion irradiations give critical temperatures for amorphisation (Tc) of 647 K for LaAlO3, 840 K for La2Ti2O7, 865 K for La2/3TiO3, and 1027 K for La2TiO5. The Tc values observed in this study, together with previous data for Al2O3 and TiO2, are discussed with reference to the melting points for the La2O3-Al2O3 and La2O3-TiO2 systems and the different local environments within the four crystal structures. Results suggest that there is an observable inverse correlation between Tc and melting temperature (Tm) in the two systems. More complex relationships exist between Tc and crystal structure, with the stoichiometric perovskite LaAlO3 being the most resistant to amorphisation.  相似文献   

14.
A new reaction of MgCl2·4H2O with CCl2F2 is investigated by DTA and TG from room temperature to 350 °C. It is observed that MgF2 was obtained between 252 and 350 °C, Below the temperature, MgCl2·4H2O dehydrates and hydrolyzes to MgCl2 and Mg(OH)Cl, which are the real reactants of the reaction with CCl2F2. The formation of MgF2 is ascribed to the reaction of MgCl2 and Mg(OH)Cl with HF, which forms by decomposition of CCl2F2 with the taking part in of H2O released from dehydration of hydrated magnesium chloride on the surface of MgCl2 and Mg(OH)Cl, which catalyzes the decomposition of CCl2F2 in this case. Consequently, the reactions are tested in the fluid-bed condition. It is found that MgF2 formed at temperatures down to 200 °C in a fluid-bed reactor. This reaction may be used as a method of disposing of the environmentally sensitive CCl2F2 (rather than release into the atmosphere). It is also a method for the preparation of MgF2.  相似文献   

15.
An experimental study on the conversion of NO in the NO/N2, NO/O2/N2, NO/C2H4/N2 and NO/C2H4/O2/N2 systems has been carried out using dielectric barrier discharge (DBD) plasmas at atmospheric pressure. In the NO/N2 system, NO decomposition to N2 and O2 is the dominating reaction; NO conversion to NO2 is less significant. O2 produced from NO decomposition was detected by an on-line mass spectrometer. With the increase of NO initial concentration, the concentration of O2 produced decreases at 298 K, but slightly increases at 523 K. In the NO/O2/N2 system, NO is mainly oxidized to NO2, but NO conversion becomes very low at 523 K and over 1.6% of O2. In the NO/C2H4/N2 system, NO is reduced to N2 with about the same NO conversion as that in the NO/N2 system but without NO2 formation. In the NO/C2H4/O2/N2 system, the oxidation of NO to NO2 is dramatically promoted. At 523 K, with the increase of the energy density, NO conversion increases rapidly first, and then almost stabilizes at 93–91% of NO conversion with 61–55% of NO2 selectivity in the energy density range of 317–550 J L−1. It finally decreases gradually at high energy density. A negligible amount of N2O is formed in the above four systems. Of the four systems studied, NO conversion and NO2 selectivity of the NO/C2H4/O2/N2 system are the highest, and NO/O2/C2H4/N2 system has the lowest electrical energy consumption per NO molecule converted.  相似文献   

16.
The NaCdVO4-Cd3V2O8 and CdO-V2O5 sections of the ternary system Na2O-CdO-V2O5 have been studied and the crystal structures of Cd3V2O8 and Cd18V8O38 compounds were determined from single-crystal X-ray diffraction data. Cd3V2O8 crystallizes with the maricite-type structure in space group Pnma, a=9.8133(10) Å, b=6.9882(10) Å, c=5.3251(10) Å and Z=4, whereas Cd18V8O38 crystallizes in space group P1 with a new-type structure, a=8.5761(14), b=8.607(3), c=12.896(2) Å, α=95.64(1), β=102.45(1), γ=108.42(1)° and Z=1. The Cd3V2O8 structure is made up of Cd1O4 infinite chains of edge-sharing Cd1O6 octahedra which are parallel to the b direction. The Cd1O4 chains are linked together by VO4 tetrahedra and strongly distorted Cd2O4 tetrahedra. The structure of Cd18V8O38 is based on an ordered three-dimensional framework of cadmium and vanadium polyhedra that share corners. The distorted CdO6 octahedra, CdO5 trigonal bipyramids and CdO5 square pyramids share corners, edges or faces.  相似文献   

17.
Differential scanning calorimetry and high temperature oxide melt solution calorimetry are used to study enthalpy of phase transition and enthalpies of formation of Cu2P2O7 and Cu3(P2O6OH)2. α-Cu2P2O7 is reversibly transformed to β-Cu2P2O7 at 338–363 K with an enthalpy of phase transition of 0.15 ± 0.03 kJ mol−1. Enthalpies of formation from oxides of α-Cu2P2O7 and Cu3(P2O6OH)2 are −279.0 ± 1.4 kJ mol−1 and −538.8 ± 2.7 kJ mol−1, and their standard enthalpies of formation (enthalpy of formation from elements) are −2096.1 ± 4.3 kJ mol−1 and −4302.7 ± 6.7 kJ mol−1, respectively. The presence of hydrogen in diphosphate groups changes the geometry of Cu(II) and decreases acid–base interaction between oxide components in Cu3(P2O6OH)2, thus decreasing its thermodynamic stability.  相似文献   

18.
Transparent glasses of various compositions in the system (100−x)Li2B4O7x(SrO-Bi2O3-Nb2O5) (where x=10, 20, 30, 40, 50 and 60, in molar ratio) were fabricated via splat quenching technique. The glassy nature of the as-quenched samples was established by differential thermal analyses. X-ray powder diffraction (XRD) and transmission electron microscopic studies confirmed the amorphous nature of the as-quenched and crystallinity in the heat-treated samples. Fluorite phase formation prior to the perovskite SrBi2Nb2O9 phase was analyzed by both the XRD and high-resolution transmission electron microscopy. Dielectric and the optical properties (transmission, optical band gap and Urbach energy) of these samples have been found to be compositional dependent. Refractive index was measured and compared with the values predicted by Wemple-Didomemenico and Gladstone-Dale relations. The glass nanocomposites comprising nanometer-sized crystallites of fluorite phase were found to be nonlinear optic active.  相似文献   

19.
用Pitzer-Simonson-Clegg热力学模型(PSC模型),分别拟合KCl-H2O、K2SO4-H2O、KNO3-H2O体系以及KNO3-K2SO4-H2O和KNO3-KCl-H2O体系水活度和溶解度实验数据,得到二元参数和三元离子相互作用参数,并以此计算3个二元盐水体系溶解度相图,及2个三元盐水体系在不同温度下的溶解度,结果表明计算值与实验值一致。  相似文献   

20.
Samples in the system Lu2−xYxSi2O7 (0?x?2) have been synthesized following the sol-gel method and calcined to 1300 °C, a temperature at which the β-polymorph is known to be the stable phase for the end-members Lu2Si2O7 and Y2Si2O7. The XRD patterns of all the compositions studied are compatible with the structure of the β-polymorph. Unit cell parameters are calculated as a function of composition from XRD patterns. They show a linear change with increasing Y content, which indicates a solid solubility of β-Y2Si2O7 in β-Lu2Si2O7 at 1300 °C. 29Si MAS NMR spectra of the different members of the system agree with the XRD results, showing a linear decrease of the 29Si chemical shift with increasing Y content. Finally, a correlation reported in the literature to predict 29Si chemical shifts in silicates is applied here to obtain the theoretical variation in 29Si chemical shift values in the system Lu2Si2O7-Y2Si2O7 and the results compare favorably with the values obtained experimentally.  相似文献   

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