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1.
在D2O化学反应气条件下环丙烷衍生物的H/D交换反应特性,发现了三种新的产物离子(M+1)^+、(M+2)^+和(M+3)^+。应用碰撞诱导碎裂(CID)技术研究了这些离子的碎裂反应特性。实验结果表明三种新的产物离子是由反应物与试剂离子间发生H/D交换反应生成的。并获得了环丙烷衍生物结构中活泼氢位置及其数量的信息。  相似文献   

2.
本文用Sampsom等的“Z-标度类氢模型和库仑玻恩交换近似”方法,修改了Sampson理论中关于屏蔽常数的定义,选用电子机轨道平均半径标准,使用多组态Hartree-Fock(MCHF)及多组态Dirac-Kock(MCDF)方法计算屏蔽常数,并给出了类Be离子C^2^+,N^3^+,O^4^+,Ne^6^+及Fe^2^2^+的电离速率系统。从计算结果,可以看到高荷电靶离子的相对论效应。  相似文献   

3.
铁酸盐的水热氧化晶化法制备及其生成条件研究   总被引:1,自引:0,他引:1  
研究了空气氧化M^2+(M=Mn、Fe、Co、Ni)和Fe^2+的碱性悬浮液制备铁酸盐MFe2O4的条件,考察了原料配比、pH值、氧化温度、氧化时间对生成MFe2O4的影响。利用XRD及SEM检测氧化过程中沉淀物的形态和结构表明,在343 ̄358K和R=2OH^-/(M^2+Fe^2+)=1.0、M^2/Fe^2+=0.5(摩尔比)下用300mL/h的空气氧化Mx/3Fe1-x/3(OH)2悬浮液  相似文献   

4.
氟化物玻璃中Tm^3+离子敏化Ho^3+离子的红外发光性质   总被引:4,自引:0,他引:4  
李毛和  祁长鸿 《光学学报》1998,18(10):454-1458
研究了氟化物玻璃中Tm^3+和Ho^3+离子的红外吸收光谱性质,用钛宝石激光器作为激发源,研究了Tm^3+离子的交叉弛豫过程和Tm^3+敏化Ho^3+2μm的红外发射光谱。研究结果表明,只有发Tm^3+离子浓度较高(~2wt%)时,才能发生较强的交叉弛豫进行,随Mo^3+离子浓度的增加,2μm的发光强度增大,当激发光波长为813nm时,2μm的发光强度最大。  相似文献   

5.
齐飞  杨新 《化学物理学报》1999,12(5):525-529
首次报道了CrC^+,MoC^+和分子离子键离解能。通过测量M^++XY→MX^++Y的反应阈值,其中XY是已知键离解能的双原子分子。可以推出MX^+的键离解能,利用同步辐射真空紫外光电离原理,电离过渡金属羰基化合物M(CO)6,从而产生金属离子M^+和金属离子碳化物MC^+,测量M^+和MC^+的出现势,结合已知的CO分子键离解能D0(C-O)=11.09eV和图中的关系,可以求得MC^+的键离  相似文献   

6.
将LCAC-SW方法推广到离子对生成反应的动力学研究,导出了计算态-态反应几率的理论公式,并在Aten-Lantin-Los两态势能面上计算得到了Na+I2→Na^++I^-2电离反应的共线选态反应几率,结果表明反应几率随碰撞能增加呈振荡变化,该反应阈能约为2.8eV,与实验值相近。  相似文献   

7.
P538萃取锰(Ⅱ)的研究   总被引:1,自引:0,他引:1  
在25±0.5℃,用P538的环己烷溶液从NaClO4-HClO4介质中萃取Mn(Ⅱ)的反应机理为离子交换机理,萃取焓△H=-196kJ.mol^-1并用Cl^-离子水合作用和Mn^2+与Cl^-形成配合物的竞争解释了萃取分配比与水相中NaCl浓度的关系。  相似文献   

8.
以NH4Cl作助溶剂,碳还原硫酸钙的方法合成了CaS:Ce。在紫外光激发下,CaS:Ce中存在着Ce^3+的^2D-^2F5/2(500nm)和^2D-^2F7/2(550nm)跃迁发射,但在蓝色光激发下,只有波峰为532nm半宽度为92nm的宽带发射。当Ce^3+的浓度为0.075mol%时,^2D-^2F5/2跃迁发射强度与^2D-^2F7/2跃迁发射强度相等,而532nm发射猝灭。  相似文献   

9.
低温宽带NaCl(OH^—):(F^+2)H色心激光的实验研究   总被引:2,自引:1,他引:1  
林碧洲  许承晃 《光学学报》1994,14(4):46-350
在NaCl晶体中掺入OH^-离子可以有效地提高F^+2心的稳定性。采用四镜折迭X型像散补偿腔,获得了峰值波长1.57μm、输出功率>250mW的低温宽带NaCl(OH^-):(F^+2)H色心激光。本文着重讨论OH^-对F^+2心的稳定作用和影响色心激光振荡的各种因素。  相似文献   

10.
报道了一种反式Curtis环的镍(Ⅱ)的配合物NiL(ClO4)2(L为2,4,4,9,11,11-六甲基-1,5,8,12-四氮杂环十四-1,5,8,12-四烯)催化NaBrO3-CH2(COOH)2(MA)-H3PO4体系的化学振荡反应。测得该体系的振荡范围,研究、分析了各物种浓度、自由基抑制剂和还原剂、Ag^+、Hg^2+以及温度对振荡反应的影响。结果表明Br^-起重要动力学控制作用,在反应  相似文献   

11.
我们首次发现的铜锌超氧歧化酶(Cu2Zn2SOD)与氨基酸等发生直接相互作用的现象,是一种前人未研究过的重要的生化新现象。在此新发现的基础上,本文用ICP,VIS,NMR和酶活性测定方法,又从不同角度拓展研究了Cu2Zn2SOD酶与两类不同化合物,  相似文献   

12.
Xu  Hui  Wu  Jun-xia  Li  Chun-lei  Zhang  Jun-long  Wang  Xiu-xiu 《Ionics》2015,21(4):1163-1170
Ionics - H+ and Co2+ ions co-doped polyaniline were synthesized by cyclic voltammetry onto the stainless steel mesh with various concentrations of cobalt chloride (CoCl2 · 6H2O) in...  相似文献   

13.
Fluorescence quenching measurements were performed on aqueous solutions of the cationic surfactant cetyltrimethylammonium halide (CTAX) and two bile salts, sodium cholate (NaC) and sodium deoxycholate (NaDC), to study the state of aggregation in the mixtures. Pyrene was used as a photoluminiscence probe in the study, and dimethylbenzophenone (DMBP) as the quencher. Analysis of time-resolved decay data with and without quencher using a simple kinetic model gave information of the different aggregation characteristics in the above two cases. Mixed micelles of CTAX/NaC were small and spherical at all compositions, while those of CTAX/NaDC tended to grow from spherical micelles to larger rod-like mixed aggregates at equimolar and close-to-equimolar concentrations. In the latter case more complex kinetics ensues and the fluorescence decays were treated using a generatized model for diffusion-controlled quenching along one dimension for infinitely long rod-like micelles. The mutual diffusion coefficient for the probe-quencherpair was determined.  相似文献   

14.
核磁共振(NMR)技术是研究表面活性剂在溶液中聚集状态的一种非常有用的工具,本文运用多种NMR技术研究了几种不同类型表面活性剂及水溶性功能高分子在水溶液中的聚集行为: 1. 季铵盐型双子表面活性剂16-4-16的聚集行为季铵盐型双子表面活性剂N,N′-双(十六烷基二甲基)-α,ω-丁烷溴化铵(16-4-16)分子中联接基团及靠近离子头的质子位于胶束的壳层, 运动受到一定限制. 而距离离子头较远的烷烃链位于胶束的内部,运动相对自由. 与对应的单链表面活性剂十六烷基三甲基溴化铵(CTAB)相比,16-4-16形成的胶束堆积更为紧密. 通过NOESY谱中交叉峰强度的定量计算,认为16-4-16在胶束中分子以上下交错排列的方式形成球形聚集体.  2. 脱氧胆酸钠与十六烷基三甲基溴化铵的相互作用在脱氧胆酸钠(NaDC)溶液中,NaDC质子H3与其他质子不同,其横向弛豫时间(T2)表现为双指数衰减,表明此质子可能存在两种不同的状态. 实验证明,其它胆酸盐的H3的横向弛豫也呈现双指数衰减. 因此推测在胆酸盐的稀溶液中,3-OH质子和羰基氧之间有可能存在氢键作用,形成了头尾相连的分子对结构.  在NaDC和CTAB的混合溶液中,两者形成1∶1的混合胶束. 用NOESY和ROESY研究混合胶束的结构,显示CTAB的离子头位于NaDC的羧酸基团附近. 这可能是正负离子之间的静电性相互作用的结果.  3. 丙烯酰胺/丙烯酸模板共聚物的微结构研究了不同pH值条件下,丙烯酰胺和丙烯酸共聚物分子在水溶液中的聚集形态. 在酸性溶液中,分子内的氢键致使聚集体形成较为紧密的堆积,侧链的苯氧基团运动受阻;随着溶液pH值的增大,丙烯酸电离产生的阴离子使得分子间的静电斥力增大,分子链变得伸展,分子间的氢键作用导致了聚集体体积变大. 当溶液呈强碱性,丙烯酸完全电离,氢键作用力被破坏,分子呈现自由伸展的状态,侧链的苯氧基团运动相对自由.  相似文献   

15.
A new fluorescent analytical methodology for the quantification of peroxynitrite (ONOO(-)) in the presence of nitric oxide (NO) was developed. The quantification of ONOO(-) is based in the oxidation of the non-fluorescent reduced fluoresceinamine to a high fluorescent oxidized fluoresceinamine in reaction conditions where the interference of NO is minimized. Screening factorial experimental designs and optimization Box-Behnken experimental design methodologies were used in order to optimize the detection of ONOO(-) in the presence of NO. The factors analysed were: reduced fluoresceinamine concentration (C( Fl)); cobalt chloride concentration (C(CoCl2)); presence of oxygen (O(2)); and, the pH (pH). The concentration of sodium hydroxide (C(NaOH)) needed to diluted the initially solution of ONOO(-) was also evaluated. An optimum region for ONOO(-) quantification where the influence of NO is minimal was identified - C(Fl) from 0.50 to 1.56 mM, C(CoCl2) from 0 to 1.252?×?10(-2) M, pH from 6 to 8 and C(NaOH) 0.10 M. Better results were found in the presence of NO at pH 7.4, C(Fl) 0.5 mM, without oxygen, without cobalt chloride and with a previous dilution of peroxynitrite solution with C(NaOH) 0.1 M. This methodology shows a linear range from 0.25 to 40 μM with a limit of detection of 0.08 μM. The bioanalytical methodology was successfully applied in the ONOO(-) quantification of fortified serum and macrophage samples.  相似文献   

16.
Wide-angle neutron scattering experiments combined with Empirical Potential Structural Refinement modelling have been used to study the detailed structure of decyltrimethylammonium bromide (C10TAB) micelles at two different temperatures; 25°C and 50°C and two concentrations; 0.4 and 0.8?M in water. At higher temperature, the micelles become smaller, and fewer counterions bind to the micelle surfaces, however, the headgroup positions are more ordered, possibly due to crowding in the smaller micelles. At higher concentration, the models suggest the micelles become elongated, although the aggregations numbers are smaller than those at the lower concentration. The smaller micelles found in 0.8?M solutions have more hydrated headgroups and lower counterion binding than the ellipsoidal micelles found in 0.4?M C10TAB solutions.  相似文献   

17.
应用可见吸收光谱首次研究了铜锌超氧化酶(Cu2Zn2SOD)活性中心金属离子在一定缓冲溶液中与无机氯化钴的直接相互作用,讨论了加入不同比例量的氯化钴,不同的pH值,不同酸盐及作用的平衡时间对这种相互作用的影响,结果发现,CoCl2中的Co(Ⅱ)与Cu2Zn2SOD中的Zn(Ⅱ)有交换作用,形成部分的Cu2中的Co2SOD,且上述四种因素对此均有不同程度的影响,本研究开创了金属酶活性中心金属离子与外  相似文献   

18.
The thermal diffusivity has been investigated in double perovskite Sr2MMoO6 (M=Fe, Mn and Co) by means of the mirage effect. We have found that the thermal diffusivity of metallic Sr2FeMoO6 is 0.39 cm2/s, which is larger than that (0.33 cm2/s) of insulating Sr2MnMoO6 and Sr2CoMoO6. We further investigate the substitution effects of the La3+ ions for the Sr2+ ions in Sr2FeMoO6 and Sr2MnMoO6, and have found that the thermal diffusivities of both samples significantly increase with the La concentration. Such an enhancement of the thermal diffusivities has been ascribed to occupation of the extra itinerant electrons on the conduction Mo4d band.  相似文献   

19.
通过化学氧化块状石墨型氮化碳(g-C3N4),获得在水中分散性好的片状g-C3N4.XRD,FTIR和XPS表明,所得片状g-C3N4含有氧官能团.这不仅可以作为锚定点负载纳米银粒子(Ag NPs),而且可以获得Ag NPs均匀分散的Ag NPS/g-C3N4纳米复合物.制备的复合材料中银纳米颗粒的重量百分比也会随着硝酸银与片状g-C3N4的质量变化而发生变化.基于g-C3N4对Co2+的明显的拉曼强度响应,Ag NPS/g-C3N4纳米复合物作为表面增强拉曼散射(SERS)传感器检测Co2+.通过拉曼强度的对照,发现随着Co2+浓度的增加,拉曼信号增加;而含有73%银纳米颗粒的Ag NPS/g-C3N4纳米复合物有高的灵敏性,检测极限浓度达到10-9 mol·L-1;复合材料同时显示出高的选择性,对其他如Cd2+,Cu2+和Zn2+的金属离子没有明显的拉曼增强信号.分析了复合材料对Co2+的增强机制.由于Co2+与g-C3N4中的=N-/-NH-基团的耦合,引发复合材料中Ag NPs聚集,从而产生局部电磁场,进而产生表面增强效应.可以预知,Ag NPS/g-C3N4纳米复合物将作为一种用于制造SERS传感器的新的理想材料.  相似文献   

20.
Bi5Fe1-xCoxTi3O15(x = 0.0, 0.2, 0.4, 0.5, 0.6, and 0.8) multiferroic ceramics are synthesized in two steps using the solid state reaction technique. X-ray diffraction patterns show that the samples have four-layer Aurivillius phases. At room temperature (RT), the samples each present a remarkable coexistence of ferromagnetism (FM) and ferroelectricity (FE). The remnant polarization (2P r ) reaches its greatest value of 14 μC/cm 2 at x = 0.6. Remnant magnetization (2M r ) first increases and then decreases, and the greatest 2M r is 7.8 menu/g when x = 0.5. The magnetic properties for x = 0.4 are similar to those for x = 0.6, indicating that the magnetic properties originate mainly from the coupling between Fe 3+ and Co 3+ ions, rather than from their own magnetic moments.  相似文献   

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