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1.
固相分光反射光度法测定药物中的合成色素   总被引:2,自引:0,他引:2  
固相分光光度法是一种简单,快速,灵敏的新型痕量的分析方法,本文首次提出用聚酰胺做吸附剂,采用改造的比色皿,测量反射器吸光度的方法,将固相分光光度法的应用由仅能分析痕量的无机离子,推广到测量药物中的合成色素,结果令人满意。  相似文献   

2.
刘文  吴自勤 《物理》1989,18(5):283-286
通过固相反应将晶态的金属转变为非晶态合金是近年来人们发现的一种新的制备北晶态合金的方法,这种方法原则上完全不受以往限制人们获得大块非晶态合金的因素的约束,因而给我们开发适合于大规模工业应用的非晶态合金生产工艺开辟了新的途径.目前,人们对固相反应非晶化机理的研究可以分为两个方面,一是固相反应的反应驱动力;二是固相反应的动力学过程.本文着重就金属多层膜间固相反应非晶化机理的实验和理论研究作了一些介绍.  相似文献   

3.
固相分光光度法是一种简单、快速、灵敏的新型痕量分析方法。本文首次提出用聚酰胺做固体吸附剂,采用激发光谱进行测定,克服了固相分光光度法背景大的缺点,同时以大幅度提高灵敏度,这种方法有良好的加标回收率、精密度及较高的准确度。并可将固相分光光度法的应用由仅能分析痕量无机离子,推广到测定合成色素。  相似文献   

4.
用固相反应法合成了名义组分为Bi1.92Pb0.32Sr2Ca1.7Mg0.3Cu3.07Ox的块状样品。X射线衍射谱(XRD)、扫描电子显微镜(SEM)和电子探计X射线分析(EDAX)结果以及块状和粉状试样的交流磁化率测量表明,样品中存在110和85K两个超导相;2223相(110K)首先在2212相(85K)晶体的晶界和外部区域生成。本文认为,最初存 关键词:  相似文献   

5.
氧碘化学激光气固相化学反应体系热力学分析   总被引:1,自引:1,他引:0  
氧碘化学激光器(COIL)的发展已经到了提高系统安全性和工作环境适应性、降低系统复杂性阶段,而改进O2(^1△g)的产生方式和方法正是这个阶段的重要工作内容之一。近期,美国空军研究实验室运用气-固相反应方式产生O2(^1△g)。采用碱金属过氧化物或碱土金属过氧化物与卤化氢反应,生成O2(^1△g)。通常气一固相反应有着反应速度慢,接触面积小,反应产物难以脱出固体表面的缺陷,使得产出率低,而不被广泛采用。但随着表面化学研究的突飞猛进,借助表面活化分子,特殊性质的表面构造,大表面的构造,都为气一固相反应的进行提供了可行途径。如果此方法能用在氧碘激光器上,将克服传统方法的诸多不足。  相似文献   

6.
综述了固相(微)萃取-室温磷光技术的主要方法以及在环境分析中的应用。主要从固相萃取的基本原理、装置、操作步骤、分离模式及填料等方面评述了固相(微)萃取技术的特点和应用,评述了室温磷光技术的优点和经典室温磷光技术在操作方法和定量分析方面存在的不足,提出了固相(微)萃取和室温磷光联用技术的必然性及其优点,并对该方法的关键技术和存在的难题进行了分析。该技术结合了富集技术与高选择性的磷光分析方法,使得分析的灵敏度进一步提高,选择性也得到了较大的改进。目前常用的固相萃取填料主要有Whatman 1PS滤纸和填充有C18或C8盘或(膜),目标分析物主要集中在多环芳烃、多氯联苯和多氯联苯呋喃等物质的分析,应用前景十分广泛。  相似文献   

7.
蒋建中 《物理学进展》2002,22(2):163-174
本文报道了晶粒尺寸对压力诱导相转变的最新进展。用热力学理论分析了造成纳米晶体材料(纳米晶)的相转变压力与同种大块材料不同的主要因素是体积变化比,表面能差和内能差。通过估算这三个因素的具体大小,可解释文献报道的实验结果,并可确定大块材料和纳米晶之间相转变压力发生差异的控制因素。在纳米晶中,晶粒尺寸对结构稳定性和相转变压力的影响与体系本身有关。  相似文献   

8.
保护介质对爆轰固相产物生成的影响   总被引:4,自引:0,他引:4       下载免费PDF全文
陈权  马峰 《高压物理学报》1998,12(2):129-133
 通过爆轰合成超细金刚石实验,对装药在不同环境下引爆后得到的固相碳产物进行比较分析,研究不同介质如氮气、水、冰、遇热分解的盐等对爆轰产物中固相碳形成的影响,同时提出用石墨化程度来比较这种影响。结果显示,介质对爆轰产物中固相碳的石墨化和超细金刚石的保护有着重要的作用。几种介质中水的保护效果较好。  相似文献   

9.
固相配位化学反应研究:LXV.成核过程的Monte Carlo研究   总被引:1,自引:0,他引:1  
缪强  胡澄 《化学物理学报》1994,7(2):118-123
本文用Monte Carlo方法模拟固体反应中的成核过程,证实了成核理论中关于成核温度及有关结论,估计了成核温度,得到了成核温度附近系统的构型分布的一些定量结果。  相似文献   

10.
徐明 《物理》2005,34(9):632-632
离子纳米晶是纳米晶材料的一个重要方面,它是通过离子性结合形成的大小处于纳米尺度的晶体.不少离子纳米晶材料已开始从实验室进入应用,如氧化锆的陶瓷增韧,氧化钛在环境保护中的应用等.由于离子在固体中的扩散激活能很高,典型的固相反应需要在高温高压才能进行,因此增加了离子纳米晶的制造成本.然而,在尺寸只有几个纳米的晶体中,离子交换反应势垒降低,无需高温高压也能进行,从而提供了一条在常温常压下合成新的离子纳米晶的途径.  相似文献   

11.
A new method of fringe-pattern analysis by spatial phase stepping (SPS) is presented. SPS combines the computational simplicity of phase stepping with the single image analysis capability of the Fourier transform method. The technique works by subdividing a linearised fringe pattern into three component images, from which the phase is calculated by a three phase step algorithm. A computer simulation has been undertaken to demonstrate the theory and enable an analysis of systematic errors. In addition, two experimental transonic flow fields are solved by SPS and a comparison is made with results derived using the Fourier transform method.  相似文献   

12.
The largest accelerator in the world, the Large Hadron Collider (LHC) at CERN, has entered into commissioning phase. It is expected that when this impressive machine will become fully operational, it will generate two counter rotating 7 TeV/c proton beams that will be made to collide, leading to an unprecedented luminosity of 1034 cm–2s–1. Total energy stored in each LHC beam is about 362 MJ, sufficient to melt 500 kg copper. Safety of operation is a very critical issue when working with such extremely powerful beams. It is important to know the consequences of an accidental release of the beam energy in order to design protection system for the equipment. For this purpose we have carried out extensive numerical simulations of the interaction of one full LHC beam with copper and graphite targets which are materials of practical importance. Our calculations have shown that the LHC protons will penetrate up to about 35 m in solid copper and 10 m in solid graphite. A very interesting outcome of this work is that the impact of the LHC beam on solid matter will generate Warm Dense Matter (WDM) and Strongly Coupled Plasmas (SCP). The beams for the LHC are pre‐accelerated in the SPS (Super Proton Synchrotron) to 450 GeV/c and transferred to LHC via two beam lines. Several SPS cycles are required to fill the LHC, in one cycle a batch with up to 288 bunches can be accelerated. From the safety point of view it is also very important to study the damage caused to the equipment in case of an accident involving an uncontrolled release of the SPS beam. For this purpose we have also carried out detailed numerical simulations of the impact of the full SPS beam on solid copper and tungsten targets. These simulations have shown that the targets are severely damaged by the beam. It is also interesting to note that also in this case, a large part of the target material is converted into WDM and SCP. This study, therefore, shows that the LHC and the SPS have the potential to be used for studying these important fields of research. However, to achieve this goal, it is necessary to advance this work by designing dedicated experiments. This work is in progress (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

13.
Recent progress is reviewed concerning the evidence for a phase change in strongly interacting matter, as predicted by Lattice QCD theory to occur at an energy density of about 2–3 GeV per cubic fermi. Experiments at the CERN SPS with Lead (208 Pb) beams show that such densities have been reached, and suggest a set of observable quantities to bear first evidence concerning the transition.  相似文献   

14.
N. Derimow  T. Clark  C. Roach 《哲学杂志》2019,99(15):1899-1913
A parallel study of mechanical alloying and solidification was carried out on FCC high-entropy alloys (HEAs) CoCrCuNi, CoCrCuFeNi and CoCrCuMnNi to investigate the effects of each processing methods on the resulting microstructure, crystal structure and microhardness. Elemental powders were mechanically alloyed followed by spark plasma sintering (SPS) at 800°C and 900°C to achieve densified discs, while arc melting was carried out from bulk pieces of the elemental metals followed by furnace annealing at 800°C and 900°C for 5?h. Both processing routes resulted in a primary FCC phase with secondary Cu-rich FCC segregation as interdendrites for the solidified alloys and particle boundaries for the SPS alloys, with the exception of a small amount of σ phase present in the SPS processed alloys. The solidification of the CoCrCuNi, CoCrCuFeNi and CoCrCuMnNi HEAs resulted in typical dendritic microstructure, followed by the precipitation of a small Cr-rich phase in the CoCrCuMnNi alloy after annealing. The grain size of the mechanically alloyed powder was approximately 20?nm from the Scherrers equation and the SPS processed HEAs consisted of a Cu-rich phase in the particle boundaries, forming cobblestone-like microstructure. The microhardness was examined in the as-cast, annealed and SPS states. It was found that the SPS processed samples had an increased microhardness by a factor of 2.5.  相似文献   

15.
Rapidity distributions of both E895 proton data at AGS energies and NA49 net proton data at SPS energies can be described reasonably well with a potential version of the Ur QMD in which mean-field potentials for both pre-formed hadrons and confined baryons are considered, with the help of a traditional coalescence afterburner in which one parameter set for both relative distance R_0 and relative momentum P_0,(3.8 fm, 0.3 Ge V/c), is used. Because of the large cancellation between the expansion in R_0 and the shrinkage in P_0 through the Lorentz transformation, the relativistic effect in clusters has little effect on the rapidity distribution of free(net) protons. Using a Woods-Saxon-like function instead of a pure logarithmic function as seen by FOPI collaboration at SIS energies, one can fit well both the data at SIS energies and the Ur QMD calculation results at AGS and SPS energies. Further, it is found that for central Au+Au or Pb+Pb collisions at top SIS, SPS and RHIC energies, the proton fractions in clusters are about33%, 10%, and 0.7%, respectively.  相似文献   

16.
采用水热合成法得到了新颖结构的配位超分子[Cu(phen)(H2O)2.SO4]。通过X射线单晶衍射、红外光谱(IR)、紫外光谱(UV-VIS-NIR)及荧光光谱进行了测定和分析指认结构分析表明:标题化合物中Cu离子的配位模式分为两种,与phen分子中的2个N原子和水分子中2个O原子是通过配位键直接配位的;与硫酸根离子中的2个O原子的配位是采取Cu离子与O原子之间形成氢键,该氢键使Cu离子和硫酸根离子中的2个O原子处于亚配位状态,因此使Cu离子处于扭曲的八面体几何构型中。晶体中存在着大量的氢键将化合物连成了1D双链结构。利用表面光电压光谱(SPS)和场诱导表面光电压光谱(FISPS)研究了化合物的表面光电行为。化合物的SPS在300~800nm范围内呈现出明显的2个正的光伏响应带。FISPS的结果显示化合物呈现出一定的p-型半导体的特征。  相似文献   

17.
A method is developed to consistently satisfy the Gibbs equilibrium conditions between the quark–gluon and hadronic phase, although each phase has been formulated in separate grand canonical partition functions containing three quark flavours. The sector in the space of thermodynamic variables where the transition takes place is restricted to a curve, according to the phase diagram of QCD. The conservation laws of quantum numbers are also imposed on the transition curve. The effect of the inclusion of the pentaquark states is considered. The data from S+S, S+Ag (SPS) and Au+Au (RHIC) are found to be compatible with the formation of a QGP phase and the occurrence of the chemical freeze-out immediately after crossing the transition line, but the data from Pb+Pb (SPS) are not. PACS 12.40.Ee; 05.70.Fh; 12.38.Mh; 24.10.Pa  相似文献   

18.
苏贤礼  唐新峰  李涵 《物理学报》2010,59(4):2860-2866
采用新颖的熔体旋甩结合放电等离子烧结技术制备了单相InSb化合物,研究了熔体旋甩工艺对其微结构以及热电性能的影响. 结果表明,熔体旋甩得到的薄带自由面主要由300 nm—2 μm的小柱状晶组成,薄带接触面为非晶或精细纳米晶,薄带经烧结后得到了具有大量层状精细纳米结构的致密块体,尺寸约为40 nm. 与熔融+放电等离子体烧结制备样品相比,在测试温度范围内(300—700 K),试样的电导率略有下降,但Seebeck系数显著增加,热导率和晶格热导率显著降低,室温下晶格热导率降低幅度约为106%,700 K下晶格热导率的降低幅度达1664%,熔融+熔体旋甩+放电等离子体烧结制备的InSb化合物试样在700 K时其最大ZT值达到049,与熔融+放电等离子体烧结试样相比提高了29%. 关键词: 熔体旋甩 n型InSb化合物 微结构 热电性能  相似文献   

19.
放电等离子固相烧结制备高密度LaB_6阴极性能   总被引:1,自引:0,他引:1       下载免费PDF全文
采用放电等离子烧结(SPS)技术,以碳化硼还原法制备的LaB6粉末为原料,制备了高致密LaB6多晶块体阴极,并系统研究了烧结温度、压力对LaB6烧结样品的物相、结构和性能的影响。确定了SPS烧结LaB6的最佳工艺为:压力50MPa,烧结温度1650℃,保温时间10min。实验结果表明:与其它LaB6多晶制备方法相比,SPS制备得到的LaB6烧结块体的力学及发射性能均有大幅提高,样品相对密度达到96.2%,维氏硬度达到1720kg/mm2,抗弯强度达到203.2MPa。样品在1520℃温度下发射电流密度达到17.41A/cm2,功函数为2.40eV。SPS制备法显著降低了LaB的烧结温度,缩短了烧结时间。  相似文献   

20.
EuTiO3 and Eu0.5Ba0.5TiO3 ceramics were synthesized using mechanochemical activation of oxide precursors and then calcined. The uniaxially as well as isostatically pressed samples were sintered in different kinds of reducing atmospheres, namely Ar?+?(7–10)%H2, respectively, 99.99%H2 in the case of pressureless sintering or in vacuum (enriched by CO vapors) in the case of pressure-assisted spark plasma sintering (SPS). The samples prepared by SPS contained the pyrochlore phase as the second phase. In contrast with SPS, pressureless sintered samples were phase pure, although thermodynamics calculations showed that CO atmosphere in SPS is more reducing than pure hydrogen. This is explained by short sintering times in SPS that do not allow establishment of the thermodynamic equilibrium. The proper choice of sintering temperature, time, and atmosphere enabled preparation of dense and phase pure samples of Eu x Ba1? x TiO3 ceramics suitable for the evaluation of “true” physical properties (e.g., infrared reflectivity), or for experimental confirmation of specific functionalities proposed from theory.  相似文献   

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