电热板消解法与微波消解法测定大气颗粒物Cu、Pb元素的对比

采用电热板消解法与微波消解法两种前处理消解方法,测定了青岛小麦岛环境监测站大气颗粒物滤膜样品的Cu、Pb含量,并对测定结果进行了分析对比.发现两种消解方法测定的Cu、Pb含量的分析精密度均较好,只是微波消解法测定值略小于电热板消解法,测定Cu元素时,两种方法不存在显著性差异,可等效使用,而测定Pb元素时,两种方法略存在差异.     

玫瑰花矿质元素测定中3种不同消解方法的比较

采用微波消解、电热板法和干灰化法对玫瑰花样品进行预处理比较,ICP-AES测定9种矿质元素的含量,检测结果表明,微波消解优于其他的两种方法,具有处理时间短、准确度高、消解完全、污染少等优点.     

微波消解-原子吸收光谱法测定沉积物中Cu、Zn、Pb、Cd和Cr

比较近海海洋沉积物成分分析标准物质(GBW 07314)在HNO3-HCl-H2O2体系微波消解和HNO3-HCl-HF-HClO4体系电热板消解下,用原子吸收分光光度计来测定样品中Cu、Zn、Pb、Cd和Cr含量,分析结果与标准值的差异情况.结果显示,两种方法消解样品,检测值在标准值范围内,但由于电热板消解方法的繁琐性,我们选择微波消解方法来前处理样品.通过对GBW 07314样品采用HNO3-HCl-H2O2体系微波消解,平行样测定(n=6),测定结果的相对标准偏差和回收率都得到满意的结果.     

蔬菜中铁含量的测定及方法比较

用分光光度法直接测定蔬菜中铁的含量,方法简便、快速、准确.分别采用浓盐酸和浓硫酸两种消解方法对样品进行处理,并对其测定结果进行比较,实验结果表明,浓硫酸消解法消解能力更强,测定更为准确.5种蔬菜中木耳铁含量最高,对指导人们合理食用蔬菜进行补铁及进一步开发蔬菜产品提供了可靠的理论依据.     

火焰原子吸收光谱法测定冬枣中的铁和锌

采用干法消解、湿法消解和非完全消解法3种方法多种体系处理冬枣样品,应用火焰原子吸收光谱法测定冬枣中铁和锌的含量.在选定的条件下,铁、锌的样品加标回收率在100.0％-101.3％之间,精密度（样品相对标准偏差RSD）均小于1.1％（n=11）.实验结果表明,湿法消解和非完全消解法的测定结果相差不大.其中非完全消解法简便、快捷,测定结果准确,更适用于冬枣中铁和锌的测定.     

微波消解-可见分光光度法测定土壤中的总铬

通过对3种常用微波消解实例进行试验,得出了微波消解土壤样品最佳的样品处理条件和仪器控制条件,优化了土壤中总铬的检测方法。以HNO3-H2O2-HF消解体系消解土壤样品效果最佳,该方法测定总铬的检出限为5m g/kg,两个土壤样品5次平行测定的RSD分别为0.49%和1.98%,加标回收率分别为97.30%和98.20%。微波消解-可见分光光度法测定土壤中的总铬是一种快速、准确、节约酸用量且低环境污染的检测方法。     

3种头发消解方法的对比研究

采用3种不同的消解方法处理同一发样,利用火焰原子吸收光谱法测定发样中Fe、Zn、Ca的含量,通过实验得出,3种消解方法对测定结果影响不大。对3种头发消解预处理方法进行分析比较,结果发现非完全消解法是值得推广的样品消解方法。     

微波消解-ICP-AES测定保鲜水果中硫含量

用硝酸-过氧化氢(4+2)混合溶液作为消解剂,微波消解法处理保鲜水果样品,采用电感耦合等离子体-原子发射光谱法(ICP-AES)测定所得样品溶液中硫的含量,选择182.0nm为测定硫的分析线,硫的检出限(3Sd)为0.065mg·L-1,样品测定的相对标准偏差(n=8)为1.90%用本法测定两个国家标准物质茶叶(GBW...     

HG-AFS测定地质样品中的总硒

采用王水消解法处理样品,用氢化物发生-原子荧光光谱法测定土壤中总硒的含量,取得了较满意的效果,并与硝酸-高氯酸电热板消解法进行了对比分析,得出结论:王水消解法不仅操作简单、省时,而且总硒测定的准确度也高于硝酸-高氯酸电热板消解法,为大量地质样品中总硒含量的测定提供了一种简便可行的方法.     

微波消解-火焰原子吸收光谱法测定海藻中的微量元素

利用微波消解-火焰原子吸收光谱法(FAAS)测定了大连产5种海藻样品中Zn、Fe、Cu、Mn 4种微量元素的含量.对微波消解条件和原子吸收光谱测定的条件进行了优化.实验结果表明,微波消解法操作简便快速、样品消解完全,空白值低、环境污染小;火焰原子吸收光谱方法选择性好,准确度高,回收率为91%-105%.样品测定结果显示...     

白光和红绿蓝光LED可调光源研制

为了提高LED光源色温和亮度的调节精度和准确度,结合色温由低向高变化时光色所呈现的渐变特点,提出了一种低色温白光LED灯珠、高色温白光LED灯珠加红绿蓝光LED灯珠补偿式调光的方法.将色温分成三个部分进行调节,每个部分选用不同的LED灯珠组合来进行调光.实验结果表明:不同组合情况下的LED光源的初始输出色温相对于目标值的偏差范围在1％以内;亮度可以在保证色温不变的情况下独立进行调节,初始输出值与目标值的偏差范围在1％以内;经过微调之后可以达到目标值;达到了色温和亮度独立调节的要求;光源发光稳定,不会因为长时间工作而影响调节精度.     

Atomic and electronic structures and stability of icosahedral nanodiamonds and onions

The relative stability of alternative carbon nanoparticles with icosahedral symmetry, such as diamond-like nanocrystallites and multiwalled fullerenes (onions), is investigated using the parametric model and the density functional tight-binding (DFTB) method. It is demonstrated that an increase in the size of particles and their hydrogenation favor the stabilization of diamond-like nanocrystallites. The formation of “intermediate” nanostructures consisting of diamond-like nanocrystallites inside the fullerene cage is revealed. The electronic spectra of icosahedral carbon nanoparticles are calculated.     

Visualization and interferometry for cylindrical and spherical sample tomography and profilometry

A technique combining image processing and laser interferometry for visualizing and detecting the deformation of transparent cylindrical and spherical sample is proposed. This deformation includes geometric deformation such as volume transition in profilometry and physical deformation such as refractive index change in tomography. Phase contour lines are used for quantitative analysis and graphical representation of the deformation. This method allows us to visually detect the spatial variation of the deformation field and to evaluate the test quality such as misalignment of optical system. A theoretical analysis using phase contour map to characterize the deformation field is described in detail. A method using phase contour map to qualify the interferometric test is proposed. Analysis of test examples is carried out. Suggestions on using phase contour line method to ameliorate test system design are finally discussed.     

Nonlocal potentials and their exact and approximate local and velocity-dependent equivalents

We show that good approximations to the exact equivalent local potential (ELP) and damping factor of a nonlocal Perey-Buck potential can be calculated in the partial wave WKB approximation of Horiuchi. The exact ELP and damping factor are obtained by means of a method previously given by one of us. We also confirm that an approximate ELP proposed by Bauhoff et al. is of comparable accuracy as the Horiuchi approximation. Thesel-dependent ELP's exhibit reduced attraction in the interior and provide a test for higher order WKB approximations. We subsequently obtain an equivalent velocity dependent potential (EVDP) which is even exactly wave function equivalent to the original nonlocal potential. This almost local potential, unlike the trivial equivalent local potential, is smooth and well-behaved and is therefore particularly useful in nuclear reactions where the off-shell behaviour of the potential is important.     

Quantum and Classical Disparity and Accord

Discrepancies and accords between quantum (QM) and classical mechanics (CM) related to expectation values and periods are generally found for both the harmonic oscillator (SHO) and a free particle in a box (FPB), which may apply generally. These indicate non-locality is expected throughout QM. The FPB energy states violate the Correspondence Principle. Previously unexpected accords are found and proven that 〈x ²〉 _CM =〈x ²〉 _QM and τ _CM =τ _QMb (beat period i.e. beats between the phases for adjoining energy states) for the SHO for all quantum numbers, n. However, for the FPB the beat periods differ at small n. It is shown that a particle’s velocity in an infinite square well varies, no matter how wide the box, nor how far the particle is from the walls. The quantum free particle variances share an indirect commonality with the Aharonov-Bohm and Aharonov-Casher effects in that there is a quantum action in the absence of a force. The concept of an “Expectation Value over a Partial Well Width” is introduced. This paper raises the question as to whether these inconsistencies are undetectable, or can be empirically ascertained. These inherent variances may need to be fixed, or nature is manifestly more non-classical than expected.