微波消解-石墨炉原子吸收法测定汽油中的锰

用微波消解方法处理汽油样品,石墨炉原子吸收光谱法测定汽油中锰含量,建立了用微波消解-石墨炉原子吸收光谱法测定汽油中锰含量的新方法。用正交试验法考察了消解时间、温度、微波功率和酸度对消解效果的影响,确定了最佳微波消解条件。研究结果显示：测定汽油样品中锰含量时相对标准偏差（n=11）≤4.12%,加标回收率在96.5%—110.2%之间。方法具有测定精密度好、样品用量少、操作简单、环境友好等优点,可用于汽油样品中锰含量的测定。     

固体进样石墨炉原子吸收光谱技术在测定大鼠脑铁含量中的应用

石墨炉原子吸收光谱法是测定动物脑组织Fe含量的常用方法,然而由于传统的液体进样方法中,样品前处理阶段用硝酸消解周期长,成本高耗时长,限制了原子吸收光谱技术在测定动物组织中Fe含量的应用。文章以SD大鼠脑部海马、纹状体、皮层为实验材料,采用固体进样器进样,利用石墨炉原子吸收光谱技术对各组织中的Fe含量进行了测定,并与传统法方法——硝酸消解样品后,液体进样的石墨炉原子吸收光谱测定结果做了比较,结果表明这两种方法所测结果无显著性差异,但应用固体进样法,样品前处理阶段明显简单,显著节省了样品准备时间,降低了工作量,使测定时间明显缩短,成本明显降低,并且能够有效避免外界因素对测定结果的影响,为固体进样法的进一步应用奠定了基础。     

原子吸收光谱中火焰法和石墨炉法测定中草药中铜元素的比较研究

分别采用火焰原子吸收光谱法和石墨炉原子吸收光谱法测定5种中草药中铜元素的含量,比较两种方法测定铜元素的优劣。浓硝酸和双氧水微波消解处理样品,火焰原子吸收光谱法和石墨炉原子吸收光谱法分别测定其吸光度,校准曲线法计算元素含量。两种方法对于铜元素的检测有一定的差异,火焰法回收率在92.0%—102.0%之间,石墨炉法回收率在92.0%—110.0%。两种方法都能满足实验要求,但各有优点。     

微波溶样-石墨炉原子吸收光谱法测定石蒜中的镉铬铅

采用微波消解技术处理样品,用石墨炉原子吸收光谱法测定,对消解试剂和微波消解条件进行了筛选和优化,研究了石墨炉原子吸收的测定条件。研究表明,以HNO₃+HClO₄+H₂O₂作为微波消解试剂最佳,在基体改进剂NH₄H₂PO₄存在下,可有效地消除基体的影响,建立了微波溶样-原子吸收光谱法测定中药石蒜中Cd, Cr和Pb的方法,其Cd, Cr和Pb的测定检出限分别为0.066 7,1.22和0.810 μg·L-1。将该法应用于石蒜样品中Cd, Cr和Pb的测定,结果令人满意,RSD小于3.1%,回收率在83.8%～118%之间。     

微波消解-原子吸收光谱法测定蔬菜中金属元素

采用微波消解的方法处理蔬菜样品,火焰原子吸收光谱法检测蔬菜中锌、铜的含量,石墨炉原子吸收光谱法检测铅、镉的含量,测定方法快速、简便、准确.     

石墨炉原子吸收法直接测定固体样品中痕量钴

本文研究了石墨炉原子吸收法直接测定固体样品中痕量钴,该方法无须对样品进行干法或湿法消解,将固体样品研磨后,过200目筛,加入0．15％琼脂溶液,均匀悬浮,由石墨炉自动进样测定,本法准确,简单,无玷污,无损失,回收率为90－96％。     

ICP-AES、石墨炉原子吸收光谱法及X射线荧光光谱法测定土壤中钒的比较

研究了土壤中钒的3种测定方法,ICP-AES、石墨炉原子吸收光谱法和X射线荧光光谱法.其中ICP-AES选用谱线V 311.1nm,用干扰系数法,干扰系数用多个土壤标样的标准值和测定值的最小二乘法来确定;石墨炉原子吸收光谱法用新、旧石墨管(热解涂层),加与不加基体改进剂(硝酸镁)分别进行测试;X射线荧光光谱法样品无需前处理、无需做校准曲线,测定前仪器用自带校正钢片单点法进行校正.通过测试结果的比较得出:ICP-AES测定土壤标样中的钒,精密度高,准确度好,适合土壤中钒的实验室分析;石墨炉原子吸收光谱法灵敏度过高(高一个数量级),信号稳定性较差,对高温元素钒的测定最好加硝酸镁机体改进剂消除基体干扰且每只石墨管分析次数不超过100次;X荧光光谱法较适合于野外监测或土壤样品无损检测,操作方便快速.     

石墨炉原子吸收光谱法测定蜂花粉中的砷

采用石墨炉原子吸收光谱法测定蜂花粉中总砷.利用微波消解法处理样品,用基体改进剂直接定容消解液,测得方法回收率为92.1％-95.2％,相对标准偏差为2.11％-3.03％,相关系数r=0.9993,检出限为o.15μg/L,本方法操作简便、快速、灵敏度高、结果准确.     

应用ICP-MS和GFAAS测定藻类食品中铅、镉的方法研究及比较

建立微波消解-电感耦合等离子体-质谱法(ICP-MS)测定藻类食品中铅、镉含量的方法,并与国家标准方法石墨炉原子吸收光谱法(GFAAS)进行了比较.样品经过微波消解,分别使用ICP-MS和GFAAS测定藻类食品裙带菜和海带中铅、镉含量,各元素校正曲线的相关系数均大于0.9991,样品分析结果RSD均小于3.6%(n=6...     

微波消解-石墨炉原子吸收光谱法测定3种中药中的铬

百合、龙眼和桂皮3种中药样品用硝酸-过氧化氢(3+2)混合溶液浸泡过夜,微波消解.并用石墨炉原子吸收光谱法(GF-AAS)测定了铬的含量.在优化的试验条件下,方法的回收率在97.3％-103.9％之间,相对标准偏差(n=6)在1.9％-4.1％之间.     

Fisher Information of Wavefunctions： Classical and Quantum

A parametric quantum mechanical wavefunction naturally induces parametric probability distributions by taking absolute square, and we can consider its classical Fisher information. On the other hand, it also induces parametric rank-one projections which may be viewed as density operators, and we can talk about its quantum Fisher information. Among many versions of quantum Fisher information, there are two prominent ones. The first, defined via a quantum score function, was introduced by Helstrom in 1967 and is well known. The second, defined via the square root of the density operator, has its origin in the skew information introduced by Wigner and Yanase in 1963 and remains relatively unnoticed. This study is devoted to investigating the relationships between the classical Fisher information and these two versions of quantum Fisher information for wavefunctions. It is shown that the two versions of quantum Fisher information differ by a factor 2 and that they dominate the classical Fisher information. The non-coincidence of these two versions of quantum Fisher information may be interpreted as a manifestation of quantum discord. We further calculate the difference between the Helstrom quantum Fisher information and the classical Fisher information, and show that it is precisely the instantaneous phase fluctuation of the wavefunctions.     

Rotational Brownian Motion on Sphere Surface and Rotational Relaxation

The spatial components of the autocorrelation function of noninteracting dipoles are analytically obtained in terms of rotational Brownian motion on the surface of a unit sphere using multi-level jumping formalism based on Debye＇s rotational relaxation model, and the rotational relaxation functions are evaluated.     

Antibody and DNA dual-labeled gold nanoparticles: Stability and reactivity

Gold nanoparticles labeled by both antibody (IgG) and single stranded DNA (ss-DNA) have been synthesized and characterized. The stability and reactivity of the dual-labeled nanoparticles were compared with the conventional IgG or ss-DNA modified nanoparticles. It was found that the IgG adsorption significantly improved the stability of the nanoparticles in aqueous solution, which is beneficial for attaching ss-DNA. The presence of IgG also effectively prohibits the desorption of ss-DNA against dithiothreitol (DTT) displacement. The coverage on dual-labeled nanoparticles was found to be 50 ± 15 ss-DNA/nanoparticle and 10 ± 2 IgG/nanoparticle, respectively, compared to the value of 70 ± 15 ss-DNA/nanoparticle of only ss-DNA-labeled gold nanoparticles. Dot-immuno and cross-linking experiments confirmed that both the IgG and ss-DNA retained their bioactivity on the nanoparticle surface. The dual-labeled nanoparticles have potential to be used as novel bio-probes for ultrasensitive detection.     

Base doping and dopant profile control of SiGe npn and pnp HBTs

Incorporation of high doping concentrations and the creation and maintaining of steep doping profiles during processing are key enabler for high level RF performance of heterojunction bipolar transistors (HBTs). In this paper, we discuss results of base doping and dopant profile control for npn and pnp SiGe HBTs fabricated within 0.25 μm BiCMOS technologies. High level of electrically active B and P doping concentrations (up to 10²⁰ cm⁻³) have been incorporated into SiGe. By adding C to SiGe steep doping profiles have been maintained due to the prevention of dopant diffusion during device processing. It is shown that broadening of P doping profiles caused by segregation could be reduced by lowering the deposition temperature for the SiGe cap. B and P atomic layer doping is shown to be suitable for the creation of steep and narrow doping profiles. This result is demonstrating the capability of the atomic layer processing approach for future devices with critical requirements of dopant dose and location control.     

Coherent and transient states studied with extreme ultraviolet and X-ray free electron lasers: present and future prospects

The most recent light sources, extreme ultraviolet (EUV) and X-ray free electron lasers (FELs), have extended tabletop laser experiments to shorter wavelengths, adding element and chemical state specificity by exciting and probing electronic transitions from core levels. Through their unique properties, combining femtosecond X-ray pulses with coherence and enormous peak brightness, the FELs have enabled studies of a broad class of dynamic phenomena in matter that crosses many scientific disciplines and have led to major breakthroughs in the last few years. In this article, we review how the advances in the performance of the FELs, with respect to coherence, polarization and multi-color pulse production, have pushed the development of original experimental strategies to study non-equilibrium behavior of matter at the femtosecond–nanometer time–length scales. In this review, the emphasis is placed on the contribution of the EUV and soft X-ray FELs on three important subjects: (i) the new regime of X-ray matter interactions with ultrashort very intense X-ray pulses, (ii) the new potential of coherent imaging and scattering for answering questions about nano dynamics in complex materials and (iii) the unique possibility to stimulate and probe nonlinear phenomena that are at the heart of conversion of light into other forms of energy, relevant to photovoltaics, femtosecond magnetism and phase transitions in correlated materials.     

Study and applications of plasma-modified Si and porous Si surfaces

In this work we have studied the electrical, chemical and physical properties of CH_x/silicon and CH_x/porous silicon (PS). The hydrocarbon (CH_x) layer has been deposited by plasma of methane under argon atmosphere. Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) Spectroscopy and photoluminescence have been used to characterize the CH_x/p-Si, CH_x/PS interfaces and, electrolyte/(CH_x/p-Si) and CH_x/PS/p-Si structures. The results show that in the case of bare silicon, the CH_x layers act as a resistant film to HF electrolyte and can be used as a potential tool for ultra-low thickness for masking and patterning. The deposition of CH_x layer on PS shows that CH_x/PS/p-Si structure presents a rectifying behaviour and can be used for detecting low concentration of large variety of gases. In addition CH_x coated PS samples exhibit more intense luminescence than that observed from an uncoated PS surface where red luminescence is shown .In conclusion, the results clearly demonstrate the interest and applications of Si and PS electrodes coated with hydrocarbon groups.     

Synthesis and characterization of disodium ethylenediaminetetraacetic acid capped and europium doped CdS nanoparticles

We present a novel two-step chemical synthesis route to produce of disodium ethylenediaminetetraacetic acid (EDTA) capped and europium doped CdS nanoparticles. First EDTA was applied to chelate with cadmium on the surface of cadmium-rich CdS nanoparticles and act as a capping agent. Further, the purified EDTA-capped particles were used to bind with Eu³⁺. The purified and redispersed particles were characterized by UV/vis absorption, photoluminescence, TEM and SEM. It was observed that Eu³⁺ on the nanoparticle surface significantly increased the band gap emission intensity of the CdS nanoparticles.     

Hydrogen implantation and diffusion in silicon and silicon dioxide

Depth profiles of hydrogen implanted into crystalline silicon in random direction at different fluences have been measured by the¹⁵N technique and by SIMS. Whereas hydrogen implanted at a fluence of 10¹⁵ ions/cm² shows some limited mobility, no such mobility is observed for higher implantation fluences. In these cases, ballistic computer codes describe the depth distributions well, within the ranges of both experimental and theoretical accuracy. Annealing up to 510 K does not change the hydrogen distributions.Furthermore, high-fluence hydrogen implantation into silicon dioxide has been examined. There is some indication for radiation-enhanced diffusion during the implantation process. Upon subsequent thermal annealing, the hydrogen is found to diffuse, probably via a trapping/detrapping mechanism associated with an OH/H₂ transformation of the hydrogen bonding.     

Inherent correlations between thermodynamics and statistical physics in extensive and nonextensive systems

With the help of a general expression of the entropies in extensive and nonextensive systems, some important relations between thermodynamics and statistical mechanics are revealed through the views of thermodynamics and statistical physics. These relations are proved through the MaxEnt approach once again. It is found that for a reversible isothermal process, the information contained in the first and second laws of thermodynamics and the MaxEnt approach is equivalent. Moreover, these relations are used to derive the probability distribution functions in nonextensive and extensive statistics and calculate the generalized forces of some interesting systems. The results obtained are of universal significance.