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1.
Mn(Ⅱ),Co(Ⅱ)与HSA相互作用的荧光光谱研究   总被引:5,自引:0,他引:5  
用荧光光谱法研究了生理pH和等离子点(pH=5.30)时Mn(Ⅱ)、Co(Ⅱ)与HSA的相互作用。根据Forste非辐射能量转移理论,得到了不同pH时Mn(Ⅱ)、Co(Ⅱ)在HSA中的第一强结合位置与Trp-214残基间的距离。这一结果远大于文献报道值,根据Mn(Ⅱ)、Co(Ⅱ)在HSA中的结合部位及HSA的畴结构对这一显著差异进行了讨论。  相似文献   

2.
掺杂功能磺酸的导电聚苯胺的合成及其红外光谱研究   总被引:8,自引:0,他引:8  
合成了参杂对甲苯磺酸(TSA),十二烷基苯磺酸(DBSA),樟脑磺酸(CSA)和磺基水杨酸(SSA)的导电聚苯胺要品:Dpan/TS,Dpan/DBSA,Dpan/CSA,Dpan/SSA,并对这些样品进行了表征,研究了它们的红外光谱特性。  相似文献   

3.
强恒磁场对动物血清中锌铜影响的研究   总被引:3,自引:0,他引:3  
用AAS研究了加磁前后的家兔和小鼠血清中锌,铜含量的变化。结果表明,家兔加磁16天后血清中锌较加磁前无显著差异(P>0.05),而血清中铜则显著降低(P<0.05);小鼠加磁16天,血清中锌,铜较对照组均有显著的降低(P<0.01)。  相似文献   

4.
本文采用硝酸溶解试样,制成试样浓度为0.5-1mg/mL,盐酸浓度为10%(V/V)的溶液,ICP-AES法直接测定铜稀土含金中0.05% ̄10%的单一稀土元素。研究了铜基体及其他元素干扰,选择了合适的分析线,优化了测定条件。方法准确,简单,快速,已用于铜稀土合金研究中的样品分析。  相似文献   

5.
本文讨论了用原子吸收和电感耦合等离子体发射光谱法(ICP-AES)测定经高压釜溶解的营养性埃及植物,如胡芦巴、甘草和莲座丛,并讨论了该法用于被消解植物样品中多元素日常分析的优点。这些样品具有较宽的元素含量范围,准确地测定这些营养性样品的主量和微量元素特别是有毒元素,对埃及人民的健康非常重要。ICP-AES法同时也用于被视为尼罗河净化剂的水生风信子的分析。分析结果表明,该植物能够有效地吸收有毒元素。被研究的植物经高压釜溶解,其溶液经原子吸收和ICP-AES法测定。作者对分析结果进行了对比,并阐明了二者之间的关系。  相似文献   

6.
用电子自旋共振(ESR)方法对非晶Ag ̄+离子导体0.85AgI~0.15Ag_4P_2O_7的热处理晶化过程进行研究,在样品中掺入微量(约1×10 ̄(-3)g/g)的Mn ̄(2+)或V ̄(4+)离子作为自旋探针离子,它们的ESR谱强度随升温线性减弱,当样品完全晶化时ESR谱消失。这样测定的样品完全晶化的温度分别为98℃(掺Mn的)和108℃(掺V的).本文还对Mn ̄(2+)和V ̄(4+)的ESR谱进行了分析。  相似文献   

7.
通过以有序的多孔氧化铝为模板,利用交流电在孔中沉积金属铜,并以此作为SERS活性基底。原子力显微镜(AFM)研究了氧化铝溶解过程中铜纳米线形貌,共焦显微拉曼则研究表面吸附SCN 的SERS光谱的变化。结果表明:铜纳米线表面SERS强度和纳米金属在表面直立的高度有关;而其频率和直立的高度无关。SCN 吸附在纳米线上比普通电化学粗糙的电极表面SERS强度高,说明纳米线(点)有望成为一种活性高,稳定性好的SERS基底。  相似文献   

8.
多波长线性回归分光光度法同时测定催化剂中钨和钼   总被引:3,自引:1,他引:2  
以水杨基荧光酮(SAF)-溴代十六烷基三甲铵(CTMAB)为显色体系,详细考查了测定条件。采用多波长线性回归分光光度法同时测定了W-Mo-Ni/Al2O3加氢催化剂中的钨和钼。相对标准偏差小于1.6%,合成样品回收率94.0%-106.4%。测定结果与比色法(分别测定)及X-射线荧光光谱法相吻合。  相似文献   

9.
文中所述的研究用实验室组装的强短脉冲供电辉光放电发射光谱(HCMSPGD-OES)实验系统,对铜基合金中的次要组分Ni,Al,Mn,Si的含量进行了测定,辉光放电(GD)源在强短脉冲供电(HCMSP)时,原子线和离子线的发射得到增强,文中选用了Ni,Al,Mn,Si的次灵敏线作分析线,对影响分析强度的因素进行了研究,在选定的实验条件下几种组分的含量进行了测定,测定结果与样品的推荐值吻合较好,六次侧  相似文献   

10.
本文讨论了用连续CO_2激光器蒸发地质粉末样品,ICP-AES测定Ba和Sr。在样品中加入适量的粘合剂和石墨粉混匀压饼,用激光全部蒸发。在蒸发室出口处加入了一只多层多孔过滤器,一定程度上改善了系统长时间工作的稳定性。对影响激光采样和ICP-AES分析性能的参数进行了研究。实验结果表明,连续激光蒸发地质粉末样品、ICP-AES测定Ba、Sr,大部分分析结果满意。在选择的系统条件下,Ba、Sr的检出限分别为2.6μg·g ̄-1和3.0μg·g ̄-1;精密度RSD分别为6.3%(470μg·g ̄-1)和5.6%(52μg·g ̄-1)  相似文献   

11.
T. B. Ghosh  Sampa Dhabal 《Pramana》2004,62(6):1319-1325
Depth dependent concentration profiles for bilayer film of Sn (500 Å)/Cu (500 A) are determined at different temperatures by X-ray photoelectron spectroscopy (XPS). Although the nature of the diffusion profile for the sample studied immediately after deposition could be explained by the existing laws, the profiles for others are found to be distinctly different and are not explained by the theories of nucleation and growth of the inter-metallic phases. Measured value of the inter-diffusion coefficient for Cu points out to the grain boundary as well as interstitial diffusion processes. It is also observed that the compositions across the bulk of the films become uniform on annealing at higher temperatures and the width of this region increases with annealing. However, the composition close to the surface is found to be entirely different from that of the bulk even on prolonged heating. The findings possibly demonstrate the importance of physical surface in influencing the solid-state reactions.  相似文献   

12.
为了研究样品温度对激光诱导击穿Cu等离子体特征参数的影响,以黄铜为研究对象,在优化的实验条件下采用波长为532 nm的Nd∶YAG纳秒脉冲激光诱导激发不同温度下的块状黄铜,测量了Cu等离子体的特征谱线强度和信噪比;同时在局部热平衡条件下利用Boltzmann斜线法和Stark展宽法分析计算了不同的样品温度条件下等离子体电子温度和电子密度。实验结果表明,在激光功率为60 mW时,随着样品温度的升高,Cu的特征谱线强度和信噪比逐渐增加,样品温度为130 ℃时达到最大值,然后趋于饱和。计算表明,黄铜样品中Cu元素Cu Ⅰ 329.05 nm,Cu Ⅰ 427.51 nm,Cu Ⅰ 458.71 nm,Cu Ⅰ 510.55 nm,Cu Ⅰ 515.32 nm,Cu Ⅰ 521.82 nm, Cu Ⅰ 529.25 nm,Cu Ⅰ 578.21 nm八条谱线在130℃的相对强度相较于室温(18 ℃)下分别提高了11.55倍、4.53倍、4.72倍,3.31倍、4.47倍、4.60倍、4.25倍、4.55倍,光谱信噪比分别增大了1.35倍,2.29倍、1.76倍、2.50倍、2.45倍、2.28倍、2.50倍,2.53倍。分析认为,升高样品温度会增大样品的烧蚀质量,相对于温度较低状态增加了等离子体中样品粒子浓度,进而提高等离子体发射光谱强度。所以,适当升高样品温度能够提高谱线强度和信噪比,从而增强LIBS技术检测分析光谱微弱信号的测量精度,改善痕量元素的检测灵敏度。同时研究了改变样品温度时等离子体电子温度和电子密度的变化趋势。计算表明,当样品温度从室温上升到130 ℃的过程中,等离子体的电子温度由4 723 K上升到7 121 K时基本不再变化。这种变化规律与发射谱线强度和信噪比变化趋势一致。分析认为,这主要是由于在升高样品温度的初始阶段,激光烧蚀量增大,等离子体内能增大,从而导致等离子体电子温度升高。当激光烧蚀样品的量达到一定值后不再变化,激光能量被激发溅射出来的样品蒸发物以及尘粒的吸收、散射和反射,导致激光能量密度降低,电子温度趋于饱和,达到某种动态平衡。选用一条Cu原子谱线(324.75 nm)的Stark展宽系数计算激光等离子体的电子密度,同时研究改变样品温度时等离子电子密度的变化趋势,计算表明在样品温度为130 ℃时,Cu Ⅰ 324.75 nm对应的等离子电子密度相较于室温(18 ℃)条件下增大了1.74×1017 cm-3。该变化趋势与电子温度的变化趋势一致。适当升高样品温度使得电子密度增大,从而提高电子和原子的碰撞几率,激发更多的原子,这是增强光谱谱线强度的原因之一。由此可见,升高样品温度是一种便捷的提高LIBS检测灵敏度的有效手段。  相似文献   

13.
We report optical and electrical properties of Cu-Ni nanoparticles in hydrogenated amorphous carbon (Cu-Ni NPs @ a-C:H) with different surface morphology. Ni NPs with layer thicknesses of 5, 10 and 15 nm over Cu NPs @ a-C:H were prepared by co-deposition of RF-sputtering and RF-Plasma Enhanced Chemical Vapor Deposition (RF-PECVD) from acetylene gas and Cu and Ni targets. A nonmetal-metal transition was observed as the thickness of Ni over layer increases. The surface morphology of the sample was described by a two dimensional (2D) Gaussian self-affine fractal, except the sample with 10 nm thickness of Ni over layer, which is in the nonmetal-metal transition region. X-ray diffraction profile indicates that Cu NPs and Ni NPs with fcc crystalline structure are formed in these films. Localized Surface Plasmon Resonance (LSPR) peak of Cu NPs is observed around 600 nm in visible spectra, which is widen and shifted to lower wavelengths as the thickness of Ni over layer increases. The variation of LSPR peak width correlates with conductivity variation of these bilayers. We assign both effects to surface electron delocalization of Cu NPs.  相似文献   

14.
Physics of the Solid State - The formation of the Cu6Sn5 intermetallic in Sn(55nm)/Cu(30nm) thin-film bilayers has been studied upon heating the film sample from room temperature to 300°C...  相似文献   

15.
Three types of copper substrates, fresh, aged (kept for years in open atmosphere) and acid washed aged, were investigated for the reflow behaviour of a solder using different heating rates. Melting point of the Sn-3.5Ag solder was lowered on the aged Cu substrate. Reduction was found to be higher in high heating rate and declined with the decrease in the heating rate. Melting point was lowered from 221 °C to 175 °C with the heating rate of 180 °C/min, but recovered to 210 °C when aged Cu substrate was washed with sulphuric acid. XPS depth profile revealed the presence of Cu2O up to the greater depth in the aged substrate compared to the fresh and acid washed aged substrates. Study showed the relation of reduction in melting point with the depth of Cu2O on the surface of aged Cu substrates. It was proposed that lower dissipation of heat generated in high heating rates by the oxidation of the flux carbon during reduction of high Cu2O amount in aged carbon was responsible for the variations in melting points.  相似文献   

16.
The temperature dependence of the photoluminescence (PhL) spectral distributions has been reported for the lithium tetraborate Li2B4O7 (LTB) and Li2B4O7:Cu (LTB:Cu) single crystals and for glassy LTB:Cu. It was found that the emission peaks of the LTB and LTB:Cu single crystals are non-elementary and splittable by temperature increase into several elementary peaks. By the sample heating the temperature quenching of PhL as well as the redistribution of the PhL intensity among elementary peaks was observed. Heating of the LTB:Cu single crystal samples caused no shift of the spectral maxima of the individual PhL peaks. The curve describing the temperature dependency of individual PhL peaks for the LTB:Cu single crystal is characterized by maxima resulting from combination of PhL and thermostimulated luminescence (TSL). The PhL intensity for glassy LTB:Cu is significantly lower than that for LTB:Cu single crystal with the equivalent copper dopant content. As compared to the LTB:Cu single crystal, the PhL spectral maximum for glassy LTB:Cu is wider and shifted to the lower energy range. Heating of the glassy LTB:Cu sample results in the PhL temperature quenching without any shift of the spectral maximum.  相似文献   

17.
The effects of cooking by microwave oven on the secondary structure of lipid and protein contents in bovine ground beef were investigated in the midinfrared region by Fourier transform infrared (FTIR) spectroscopy to highlight the nonthermal effects of microwave oven heating. Samples of bovine ground beef were cooked in a conventional electric oven at the temperature of 175°C for 15 min and in a microwave oven at 800 W for 1½ min. Spectra analyses of bovine meat after cooking in the conventional oven evidenced a relevant increase in intensity of the carbonyl band at 1742 cm?1 and of the methylene group at 2921 and 2853 cm?1 that can be attributed to the Maillard reaction. In contrast, the increase in intensity of these bands after microwave oven heating was less than that which occurred after conventional cooking, showing that the temperature in ground beef meat samples during microwave heating was less than that induced by conventional heating. Spectral analysis in the amide I, II, and III regions showed that a significant increase in intensity occurred in the region from 1660 to 1675 cm?1 and around 1695, 1635, 1575, and 988 cm?1 after cooking by means of a microwave oven. These features, which can be attributed to β-turns and β-sheet structures, are characteristic of disorder processes in meat protein contents and increasing transition dipole coupling due to higher contents in aggregated β-sheet structures. This result highlighted nonthermal effects of microwave oven heating in the protein's secondary structure.  相似文献   

18.
杨雪  李苏宇  姜远飞  陈安民  金明星 《物理学报》2019,68(6):65201-065201
研究了不同温度下聚焦透镜到样品表面距离对激光诱导击穿光谱(laser-induced breakdown spectroscopy,LIBS)强度的影响,使用Nd:YAG脉冲激光激发样品并产生等离子体,探测的等离子体发射的光谱线为Cu(Ⅰ)510.55 nm,Cu(Ⅰ)515.32 nm和Cu(Ⅰ)521.82 nm.使用透镜的焦距为200 mm,测量的聚焦透镜到样品表面距离的范围为170—200 mm,样品温度从25℃升高到270℃,激光能量为26 mJ.总体上,升高样品温度能有效地提高LIBS光谱的辐射强度.在25℃和100℃时,光谱强度随着聚焦透镜到样品表面距离的增加而单调增加;在样品温度更高(150, 200, 250和270℃)时,光谱强度随着距离的增加出现先升高而后又降低的变化.同时,在样品接近焦点附近,随着样品温度的升高,LIBS光谱强度的变化不明显,还可能出现光谱强度随着样品温度升高而降低的情况,这在通过升高样品温度来提高LIBS光谱强度中特别值得我们注意.为了更进一步了解这两个条件对LIBS的影响,计算了等离子体温度和电子密度,发现等离子体温度和电子密度的变化与光谱强度的变化几乎一致,更高样品温度下产生的等离子体温度和电子密度更高.  相似文献   

19.
The isothermal and non-isothermal ageing of an Al-2.4 wt% Cu alloy have been studied using X-ray diffraction analysis and differential scanning calorimetry (DSC) at different heating rates. Quantitative metallography methods have been applied to measure the corresponding transformed volume fractions at various temperatures and times of precipitation. The variation of the heating rate using DSC technique has allowed us to calculate two kinetics parameters of precipitation which are the Avrami exponent and the activation energy of the process using Kissinger, Ozawa and Bosswell methods. These parameters are similar to those found for the precipitation reaction of θ′ and θ (Al2Cu) phases.  相似文献   

20.
电沉积复合丝及其巨磁阻抗效应的研究   总被引:1,自引:0,他引:1  
采用脉冲电沉积工艺在Cu丝上沉积Fe Ni合金镀层 ,成功地制备出巨磁阻抗效应 (GMI)复合丝材料 ,研究了复合丝的磁性能和巨磁阻抗效应 .复合丝外壳磁性镀层软磁性越好 ,巨磁阻抗效应越明显 ,制备的复合丝最高巨磁阻抗效应为 2 7.19% .研究了复合丝阻抗与巨磁阻抗比值GMI随外加磁场的变化 ,其变化曲线的形状受复合丝磁各向异性场的影响 .此外 ,还研究了复合丝巨磁阻抗效应与驱动交变电流频率的关系 ,复合丝Fe17Ni83 样品巨磁阻抗效应的临界频率为 30kHz(GMI为 9.95 % ) ,特征频率为 30 0kHz(GMI为 2 7.19% ) ,截止频率为 10MHz (GMI为 10 .36 % ) .如此低的临界频率和特征频率及较宽的频率段对于实际应用非常有利 .  相似文献   

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