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1.
在常温下合成了以邻苯二酚为配体,分别以乙二胺、1,2-丙二胺、1,3-丙二胺为抗衡离子的7种手性钼钨八面体配合物(NH2CH2CH2NH3)3[Mo(V)O2(OC6H4O)2](1),(NH2CH2CH2NH3)2[W(VI)O2(OC6H4O)2](2),(NH2CH2CH2NH3)2.5[Mo(V)0.5W(VI)0.5O2(O2C6H4)]2](3),(NH3CH2CHNH2CH3)3[Mo(V)O2(OC6H4O)2](4),(NH3CH2CHNH2CH3)2[W(VI)O2(OC6H4O)2](5),(NH3CH2CHNH2CH3)2.5[Mo(V)0.5W(VI)0.5O2(OC6H4O)2](6),(NH3CH2CH2CH3NH2)2.5[Mo(V)0.5W(VI)0.5O2(OC6H4O)2](7),并在生理条件下对其与ATP的相互作用进行了液体NMR研究,发现标题配合物的中心金属离子在纯D2O溶剂中大多数以+5价形式存在,W(VI)被还原为W(V),但与ATP混合后又转化为+6价,配合物原有的顺磁性特征完全消失.研究还发现ATP可以促进中心离子与原配体发生解离.  相似文献   

2.
研究了Er1.0P5O14铒非晶玻璃的红外量子剪裁现象. 从吸收谱和激发光谱的计算比较中肯定了Er1.0P5O14非晶 玻璃的1537.0 nm红外荧光为多光子量子剪裁荧光. 从Er1.0P5O14非晶玻璃的可见和红外荧光发射光谱中发现激发2H11/2, 4G11/24G9/2能级所导致的4I13/24I15/2量子剪裁红外荧光很强;基于自发辐射速率、无辐射弛豫速率和能量传递速率等参数的计算,对其量子剪裁机理进行了分析.发现起源于基态的强下转换能量传递{2H11/24I9/2,4I15/24I13/2},{4G11/24I13/2, 4I15/22H11/2},{4G9/24F7/2,4I15/24I13/2}和{4G9/24I13/2, 4I15/22H11/2}是导致Er1.0P5O14非晶玻璃具有强的三光子和四光子量子剪裁红外荧光的原因.研究结果对改善太阳能电池效率有一定意义.  相似文献   

3.
We have measured the resistivities of Al2O3-Bi2Sr1.8Ca1.2Cu2Oy and MgO-Bi2Sr1.8Ca1.2Cu2Oy composites with the nominal Bi2Sr1.8Ca1.2Cu2Oy volume fraction, 2212, ranging from 0.15 to 1.00. For the Al2O3-Bi2Sr1.8Ca1.2Cu 2Oy composites, we find for the samples with 2212≥0.6 that the superconducting transition temperature, Tc, is not disturbed by the addition of Al2O3. For 2212<0.3, no zero-resistivity state is observed. For the MgO-Bi2Sr1.8Ca1.2Cu2Oy composites, Tc is barely disturbed for the samples with ρ2212≥0.7. No superconducting state is observed for the samples with ρ2212<0.35. The variation of (300 K) with ρ2212 indicates a three-dimensional percolating Bi-Sr-Ca-Cu-O matrix occurring at ρ2212≈0.19 and ≈0.15 in Al2O3-Bi2Sr1.8Ca1.2 Cu2Oy and MgO-Bi2Sr1.8Ca1.2Cu2Oy, respectively. Both resistivity and magnetization measurements suggest that the reactions of Bi2Sr1.8Ca1.2Cu2Oy with MgO are weaker than with Al2O3.  相似文献   

4.
As a key factor leading to the pressure-dependent R1-line-shift reversal and R1-state lifetime, at 10 K, the pressure-dependent variation of mixing-degree of |t22(3T1)e4T2〉 and |t232 E〉base-wavefunctions in the wavefunction of R1 state of LLGG:Cr3+ has been calculated and analyzed. From this, the physical origin of the pressure-dependent R1-line-shift reversal has been revealed. Furthermore, by using the pressure-dependent values of the sum of all square mixing-coefficients of |t22(3T1)e4T2〉in the wavefunction of R1 state, the lifetimes of R1 state of LLGG:Cr3+ at various pressures have been calculated, which are in good agreement with observed results. The quantum anticrossing effect between t232E and t22(3T1)e4T2 levels due to both spin-orbital interaction and electron-phonon interaction is remarkable, which is related to the admixture of |t22(3T1)e4T2〉and |t232 E〉as well as the low-high crystal-field transition.  相似文献   

5.
于晶杰  肖志国  宁桂玲 《发光学报》2013,34(12):1561-1566
采用高温固相法合成了荧光体Ba10(PO44(SiO42:Ce3+和Ba10(PO44(SiO42:Eu2+,研究了两种荧光体的光谱特性。结果表明,两者都呈现较强的宽带激发特征。根据同种基质中Eu2+和Ce3+两种离子光谱特征的相关性,通过测得的Ba10(PO42(SiO42基质中Ce3+的光谱数据估算了Ba10(PO42(SiO42:Eu2+中Eu2+的斯托克斯位移(ΔS)和激发能量,估算结果与Ba10(PO42(SiO42:Eu2+样品的光谱分析结果十分吻合。Ba10(PO42(SiO42:Eu2+可以同时被紫光和蓝光激发,发出偏白的绿光,可用作白光LED的荧光粉。  相似文献   

6.
CaMoO4:Eu3+,Bi3+,Li+红色荧光粉的共沉淀制备与表征   总被引:1,自引:0,他引:1  
关荣锋  孙倩  李勤勤  许宁 《发光学报》2013,34(8):1000-1005
采用共沉淀法合成了红色荧光粉Ca0.75MoO4:Eu0.253+、Ca0.75MoO4:Eu0.25-x3+,Bix3+及Ca0.5MoO4:Eu0.25-2x3+, Bix3+,Li0.25+x+,并采用X射线衍射(XRD)、拉曼光谱,扫描电镜(SEM)和荧光光谱(PL)测定分析了其结构形貌特征及发光性能。结果表明:制备的CaMoO4:Eu3+,Bi3+,Li+红色荧光粉为白钨矿结构,颗粒尺寸约为0.5~1 μm。掺杂Bi3+的Ca0.75MoO4:Eu0.25-x3+,Bix3+的相对发光强度明显高于未掺Bi3+的Ca0.75MoO4:Eu0.253+荧光粉。Bi3+离子的掺杂将吸收来的能量传递给激活离子Eu3+,起到了能量传递的作用。当Bi3+掺杂量为x=0.005时,在395 nm激发下,主发射峰在616 nm处的相对发光强度最大,但掺杂浓度过高时会出现浓度猝灭现象。另外,电荷补偿剂的掺入能够解决材料中因同晶取代引起的电荷不平衡的问题,以Li+作电荷补偿剂、Eu3+和 Bi3+共掺合成的Ca0.5MoO4:Eu3+0.23,Bi0.013+,Li+0.26红色荧光粉的发光性能强于Ca0.75MoO4:Eu0.253+、Ca0.5MoO4:Eu0.253+, Li0.25+及Ca0.75MoO4:Eu0.243+,Bi0.013+。  相似文献   

7.
本研究通过壳模型计算研究了N=51的同中子素91Zr、93Mo和95Ru中高自旋晕态21/2+的同核异能态现象。计算发现,低角动量的p1/2轨道上的质子是仅在93Mo中存在21/2+晕阱的主要原因。同时,本工作还研究了N=52的同中子素92Zr、94Mo和96Ru中101+-121+能级结构的系统性,发现94Mo中的101+-121+能级间隙相对最小,考虑到与93Mo的17/21+-21/21+能级相似的组态,这一结果为93Mo中出现21/2+晕阱提供了补充性的论证。Isomerism of the high-spin yrast 21/2+ states of the N=51 isotones 91Zr, 93Mo and 95Ru has been investigated using the shell model calculations. It is found that the low-j πp1/2 is responsible for the only yrast trap in 93Mo. In addition, the relatively smaller 101+-121+ level spacing in 94Mo has been found by investigating the systematics of the 101+-121+ level structures in the N=52 isotones 92Zr, 94Mo and 96Ru. This result provides a supplementary argument to the origin of the 21/2+ yrast trap in 93Mo from the viewpoint of the similarity between the configurations of 101+-121+ states in 94Mo and those of 17/21+-21/21+ states in 93Mo.  相似文献   

8.
本文用X射线和差热分析方法对BaO-Li2O-B2O3三元系中的两个截面:BaB2O4-Li2B2O4和BaB2O4-Li2O作了研究。在BaB2O4-Li2B2O4赝二元系中发现了一个新的化合物4BaB2O4·Li2B2O4。化合物在930±3℃由包晶反应形成,并与Li2B2O4形成共晶反应。共晶温度为797±3℃,共晶点组分为79mol%Li2B2O4。在BaB2O4-Li2O截面中也存在化合物4BaB2O4·Li2B2O4,其包晶反应温度从930±3℃随Li2O含量增加下降到908±3℃。在组分60mol%Li2O处形成另一个新的化合物2BaB2O4·3Li2O。该化合物在630±3℃也是由包晶反应形成,并与Li2O和Li2CO3分别形成共晶反应,共晶温度分别为400±3℃和612±3℃。在BaB2O4-Li2B2O4和BaB2O4-Li2O体系中都没有观察到固溶体。用计算机程序分别对化合物4BaB2O4·Li2B2O4和2BaB2O4·3Li2O的X射线粉末衍射图案进行了指标化,其结果:4BaB2O4·Li2B2O4的空间群为Pmma,a=13.033?,b=14.630?,c=4.247?,每个单胞包含两个化合式单位;2BaB2O4·3Li2O的空间群为Pmmm,a=4.814?,b=9.897?,c=11.523?,每个单胞也含有两个化合式单位。 关键词:  相似文献   

9.
Traditional ligand-field theory has to be improved by taking into account both pure electronic contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of improved ligand-field theory, the R line, t23 2T1 and t23 2T2 lines, t22 (3T1)e4T2, t22 (3T1)e4T1 and t2 e2(4A2)4T1 bands, g factors of t23 4A2 and t23 2E, four strain-induced level-splittings and R-line thermal shift of MgO:V2+ have been calculated. The results are in very good agreement with the experimental data. It is found that for MgO:V2+, the contributions due to electron-phonon interaction (EPI) come from the first-order term; the contributions from the second-order and higher terms are insignificant. In thermal shift of R line of MgO:V2+, the temperature-dependent contribution due to EPI is dominant. The results obtained in this work may be used in theoretical calculations of other effects of EPI.  相似文献   

10.
陈佩赓  鲁家导  郭文安  李永良  高有辉 《物理学报》2014,63(18):187302-187302
以氧化铝纳米孔为模板,采用直流电化学沉积的方法制备了Cd_(0.96)Zn_(0.04)S/Cd_(0.97)Mn_(0.03)S/Cd_(0.96)Zn_(0.04)S量子阱纳米线阵列,并系统研究了该纳米线阵列在不同温度和不同磁场下的电学输运特性.随着外磁场的变化,样品表现出共振传输特性.通过量子阱理论对实验现象进行了分析,直接得到了稀磁层Cd_(0.97)Mn_(0.03)S中s-d交换作用常数N_0α的定量结果.研究发现该交换作用常数随温度具有e~(-1/T)的变化趋势.  相似文献   

11.
The steady state and transient fluorescence spectra of CaF2: Dy3+ have been studied using Ar+ and N2 lasers in the temperature range 77–673 K and in the wavelength region 4500–9000 Å. The spectra show the presence of two types of centers (type A and type B) with decay times of 1.3 and 3.5 ms. The observed spectrum is mostly due to type A centers. Three new groups of fluorescence 4F9/26H11/2, 4F9/2−(6H9/2, 6F11/2) and 4F9/2−(6H7/2, 6F9/2) have been observed for type A centers, and a tentative assignment of the positions of the Stark levels of 6H11/2, (6H9/2, 6F11/2) and (6H7/2, 6F9/2) has been made. The change in the intensity of the transitions with temperature and excitation wavelength are discussed.  相似文献   

12.
于潘龙  田莲花 《发光学报》2018,39(9):1200-1206
采用高温固相法制备了颜色可调的NaTaOGeO4∶Tb3+,Mn2+荧光粉,并研究了其发光特性以及能量传递机理。在244 nm激发下,NaTaOGeO4∶Tb3+的发射光谱的发射峰分别位于380,413,436,492,544 nm,分别属于Tb3+5D37FJ5D47FJ(J=6,5,4)能级跃迁,为蓝光和绿光发射。在280 nm波长激发下,在492 nm和544 nm处有较强的发射峰,分别属于Tb3+5D47F65D47F5能级跃迁,为绿光发射。在248 nm波长激发下,NaTaOGeO4∶Mn2+的发射光谱由位于576 nm处的宽带组成,属于Mn2+4T16A1能级跃迁。当在NaTaOGeO4∶Tb3+荧光粉中共掺杂Mn2+时,可以同时观察到Mn2+和Tb3+的发射峰,通过改变浓度掺杂比,可以得到颜色可调控的荧光粉。  相似文献   

13.
The mechanical anisotropy, structural properties, electronic band structures and thermal properties of C2 N2 (CH2 ), Si2 N2 (SiH2 ) and Ge2 N2 (GeH2 ) are detailed and investigated in this work. The novel silicon nitride phase Si2 N2 (SiH2 ) and germanium nitride phase Ge2 N2 (GeH2 ) in the Cmc 21 structure are proposed in this work. The novel proposed Si2 N2 (SiH2 ) and Ge2 N2 (GeH2 ) are both mechanically and dynamically stable. The electronic band calculation of the HSE06 hybrid functional shows that C2 N2 (CH2 ), Si2 N2 (SiH2 ) and Ge2 N2 (GeH2 ) are all wide band gap semiconductor materials, and C2 N2 (CH2 ) and Si2 N2 (SiH2 ) are direct band gap semiconductor materials, while Ge2 N2 (GeH2 ) is a quasi-direct band gap semiconductor material, the band gap of C2 N2 (CH2 ), Si2 N2 (SiH2 ) and Ge2 N2 (GeH2 ) are 5.634 eV, 3.013 eV, and 2.377 eV, respectively. The three-dimensional and plane distributions of Young’s modulus, shear modulus and Poisson’s ratio of C2 N2 (CH2 ), Si2 N2 (SiH2 ) and Ge2 N2 (GeH2 ) show that these materials have different degrees of mechanical anisotropy. The order of Young’s modulus of Si2 N2 (SiH2 ) and Ge2 N2 (GeH2 ) in different directions is different from that of C2 N2 (CH2 ). When the tensile axis is in a particular direction, the order of the Young’s modulus of Si2 N2 (SiH2 ): E [110] <E [120] <E [111] <E [101] <E [010] =E [100] <E [011] <E [001], and the order of the Young’s modulus of Ge2 N2 (GeH2 ): E [110] <E [111] <E [101] <E [120] <E [100] <E [010] <E [011] <E [001] .  相似文献   

14.
郭海涛  张鸣杰  许彦涛  肖旭升  杨志勇 《中国物理 B》2017,26(10):104208-104208
The structures of pseudo-binary GeS_2–Sb_2S_3, GeS_2–CdS, Sb_2S_3–CdS, and pseudo-ternary GeS_2–Sb_2S_3–CdS chalcogenide systems are systematically investigated by Raman spectroscopy. It is shown that a small number of [S_3Ge–GeS_3]structural units(SUs) and-S-S-/S8 groups exist simultaneously in GeS_2 glass which has a three-dimensional continuous network backbone consisting of cross-linked corner-sharing and edge-sharing [GeS_4] tetrahedra. When Sb_2S_3 is added into GeS_2 glass, the network backbone becomes interconnected [GeS_4] tetrahedra and [SbS_3] pyramids. Moreover, Ge atoms in[S_3Ge–GeS_3] SUs tend to capture S atoms from Sb_2S_3, leading to the formation of [S_2Sb–SbS_2] SUs. When CdS is added into GeS_2 glass, [Cd_4GeS_6] polyhedra are formed, resulting in a strong crystallization tendency. In addition, Ge atoms in[S_3Ge–GeS_3] SUs tend to capture S atoms from CdS, resulting in the dissolution of Ge–Ge bond. Co-melting of Sb_2S_3 or CdS with GeS_2 reduces the viscosity of the melt and improves the homogeneity of the glass. The GeS_2 glass can only dissolve up to 10-mol% CdS without crystallization. In comparison, GeS_2–Sb_2S_3 glasses can dissolve up to 20-mol% CdS,implying that Sb_2S_3 could delay the construction of [Cd_4GeS_6] polyhedron and increase the dissolving amount of CdS in the glass.  相似文献   

15.
An attempt is made to synthesize Nd2Co14C compound by mechanical alloying Nd16Co76B8−xCx (0x8) alloys and subsequent annealing. Phase formation and magnetic properties of Nd2Fe14B-type Nd16Co76B8−xCx alloys and their hydrides are investigated. The Nd2Co14(B,C) phase with Nd2Fe14B-type structure is formed for Nd16Co76B8−xCx (0x7) alloys, while NdCo7Cδ phase with TbCu7-type structure is observed in Nd16Co76C8 alloy. The lattice parameter c of the Nd2Co14(B,C) phase decreases with increasing the carbon content. A limit volume of the unit cell to form the Nd2Fe14B-type structure is estimated to be 0.870 nm3. The spin-reorientation temperature TSR increases with increasing the carbon content, due to an enhancement of magnetocrystalline anisotropy caused by carbon substitution for boron. After hydrogenation, the lattice expansion is observed for Nd16Co76B8−xCx (0x7) alloys. The spin-reorientation temperature of Nd16Co76B8−xCxHy (0x7) is much lower than that of the host alloys. Some structural and magnetic properties of hypothetic Nd2Co14C and Nd2Co14CHy compounds are estimated by extrapolation.  相似文献   

16.
本文用自由基捕捉剂苯亚甲基叔丁基氮氧化物(PBN)与ESR相结合的方法研究了十种取代苯基重氮盐RC6H4N2+BF4-(R=F,Cl,Br,NO2,OCH3及CH3)在乙腈中电解还原产生的活泼自由基。结果表明:1.RC6H4N2+BF4-电解还原时产生RC6H4自由基,并能被捕捉剂PBN所捕捉,以形成稳定的自由基加合物[RC6H4-PBN]·。2.由[RC6H4-PBN]·ESR谱的超精细裂分常数算出的二面角θβ值大小与处于不同位置的给定取代基R的关系为:θβ(O-R) < θβ(m-R) < θβ(P-R)  相似文献   

17.
采用高温固相法合成Sr3B2O6:Eu3+,Li+红色荧光粉,考察了激活剂Eu3+和电荷补偿剂Li+浓度对Sr3B2O6:Eu3+,Li+荧光粉发光性能的影响。结果表明:适量掺杂Eu3+、Li+离子并不改变Sr3B2O6的结构。当Eu3+掺杂量为4%、Li+的掺杂量为8%时,在900 ℃下灼烧2 h可以得到发光性能最佳的Sr2.9B2O6:0.04Eu3+,0.08Li+红色荧光粉。以394 nm的近紫外光激发时,Sr3B2O6:Eu3+,Li+荧光粉发射出红光,对应于Eu3+的4f-4f 跃迁,其中以614 nm附近的5D07F2跃迁发光最强,是一种有潜力用于白光LED的红色荧光粉。  相似文献   

18.
Passivation treatment on indium-doped Hg0.8Cd0.2Te epitaxial layers grown on p-Cd0.96Zn0.04Te substrates by molecular beam epitaxy has been performed in order to improve the surface stability of the Hg0.8Cd0.2Te layers. Room-temperature capacitance–voltage measurements clearly revealed metal-insulator–semiconductor (MIS) behavior for the Al/ZnS/passivated Hg0.8Cd0.2Te layer/Cd0.96Zn0.04Te diodes. The fast state density and the fixed charge density of the Al/ZnS/passivated Hg0.8Cd0.2Te/Cd0.96Zn0.04Te diode with a sulfur-treated Hg0.8Cd0.2Te layer were smaller than those with a chemically oxidized Hg0.8Cd0.2Te layer. The interface state density at the ZnS/sulfur-treated Hg0.8Cd0.2Te interface were low at 1011 eV−1 cm−2 at the middle of the Hg0.8Cd0.2Te energy gap. These results indicate that the Hg0.8Cd0.2Te epilayer is significantly passivated by sulfur treatment and that the passivated Hg0.8Cd0.2Te layers can be used for Hg1−xCdxTe-based MIS diodes and MIS field-effect transistors.  相似文献   

19.
While YSr2Cu3O7 cannot be prepared under ambient conditions, partial substitution of the phosphate group for copper, as in YSr2Cu2.8(PO4)0.2Oy, stabilizes this phase in the orthorhombic structure, but the material is not superconducting. Superconductivity in YSr2Cu2.8(PO4)0.2Oy is obtained by increasing the hole concentration through partial substitution of Y by Ca, as in Y0.7Ca0.3Sr2Cu2.8(PO4)0.2Oy (Tc≈40 K). By incorporating the phosphate group in orthorhombic YBaSrCu3O 7, a stable tetragonal derivative of the formula YBaSrCu2.8(PO4)0.2Oy (Tc≈ 47 K) has been prepared; the Tc increases to 70 K by partial substitution of Y by Ca as in Y0.7Ca0.3BaSrCu2.8(PO4)0.2Oy.  相似文献   

20.
用高温固相法合成了用于白光LED的Na2Ca4(1-x-y)(PO4)2SiO4:xEu3+,yBi3+红色荧光粉.研究了助熔剂H3BO3、二次煅烧时间和稀土掺杂量等制备条件对样品发光性质的影响.结果表明,在1 200℃、助熔剂H3BO3加入量为样品质量的3.8%时可得到更有利于发光的α-NCPS基质,而且掺入Eu3+...  相似文献   

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