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91.
研究了用酸分解试样后不需分离基体直接用电感耦合等离子体原子发射光谱(ICP-AES)法测定铅锭中银、铜、铋、砷、锑、锡、锌、铁、镉、镍、铊11种杂质元素的方法。优化了样品前处理条件及仪器检测条件。方法的检出限为0.0012~0.0168μg/mL,回收率为89%~110%,RSD为2.3%~5.0%。方法简便快速,检出限低,精密度和准确度能满足铅锭中杂质元素的检测要求,具有较强的实用性和可操作性,可用于铅锭中杂质元素的测定。 相似文献
92.
93.
C Schorsch A.H Clark M.G Jones I.T Norton 《Colloids and surfaces. B, Biointerfaces》1999,12(3-6):317-329
The stability of dairy emulsions containing both proteins and polysaccharides is mainly controlled by the nature of the protein–polysaccharide interaction. This work describes the behaviour of a micellar casein/locust bean gum (LBG) model system, and examines the effect of adding sucrose. For such systems a very high incompatibility has been demonstrated leading to thermodynamic separation into two distinct phases, one rich in protein and the other in polysaccharide. The second virial coefficient approach described by Edmond and Ogston was adopted to clarify the effect of sucrose on the micellar casein/LBG phase diagrams. 相似文献
94.
D. Shakhvorostov M. A. Nicholls P. R. Norton M. H. Müser 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,76(3):347-352
Recent studies on a variety of metal phosphates (MP) have revealed that MPs
tend to be soft at ambient pressure if the coordination on the metal cation is
low and the degree of hydration or hydrogenation is high, while they are stiff
otherwise.
In addition, the softer MPs were found to stiffen dramatically more quickly
with increasing pressure than the stiffer MPs.
Here we review these findings and support their relevance with
new results on the
mechanical properties of tribofilms aged in air of relative humidity,
which were produced from commercial,
zinc phosphate-containing lubricant packages via heating and rubbing.
We find that the films can soften quite substantially after having been
exposed to humidity, as to be expected from the studies of bulk MPs.
Moreover, when the hydrated films are exposed to high loads, the
force-distance withdrawal curve becomes identical to that of unaged,
non-hydrated films.
A straightforward explanation of this observation is that
large pressure reverses the hydration of the tribofilms. 相似文献
95.
Sha MY Walton ID Norton SM Taylor M Yamanaka M Natan MJ Xu C Drmanac S Huang S Borcherding A Drmanac R Penn SG 《Analytical and bioanalytical chemistry》2006,384(3):658-666
Single-nucleotide polymorphisms (SNP) are the most common form of sequence variation in the human genome. Large-scale studies
demand high-throughput SNP genotyping platforms. Here we demonstrate the potential of encoded nanowires for use in a particles-based
universal array for high-throughput SNP genotyping. The particles are encoded sub-micron metallic nanorods manufactured by
electroplating inert metals such as gold and silver into templates and releasing the resulting striped nanoparticles. The
power of this technology is that the particles are intrinsically encoded by virtue of the different reflectivity of adjacent
metal stripes, enabling the generation of many thousands of unique encoded substrates. Using SNP found within the cytochrome
P450 gene family, and a universal short oligonucleotide ligation strategy, we have demonstrated the simultaneous genotyping
of 15 SNP; a format requiring discrimination of 30 encoded nanowires (one per allele). To demonstrate applicability to real-world
applications, 160 genotypes were determined from multiplex PCR products from 20 genomic DNA samples. 相似文献
96.
[reaction: see text] Tautomeric equilibria involving hydrogen migration in methylacenes were explored computationally using DFT methods. As the aromatic system becomes more extended, the methylene isomer is predicted to become favored. Reasonable-looking pericyclic sigmatropic hydrogen shifts are found to be energetically prohibitive, and bimolecular mechanisms involving radical pair intermediates are energetically feasible. 相似文献
97.
ER Badman GE Patterson JM Wells RE Santini RG Cooks 《Journal of mass spectrometry : JMS》1999,34(8):889-894
Dual-detector differential non-destructive Fourier transform detection in a quadrupole ion trap is shown to improve signal intensity and reduce noise compared with spectra recorded using a single detector. A larger area detector in each end-cap electrode is machined to fit its hyperbolic shape and so minimize field imperfections on the z-axis. Argon, acetophenone and bromobenzene spectra were recorded to allow a comparison between single- and dual-detector (differential) modes of detection and to demonstrate the improvement achieved with differential detection. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
98.
John D. Norton 《Foundations of Physics》2013,43(11):1384-1410
Brownian computers are supposed to illustrate how logically reversible mathematical operations can be computed by physical processes that are thermodynamically reversible or nearly so. In fact, they are thermodynamically irreversible processes that are the analog of an uncontrolled expansion of a gas into a vacuum. 相似文献
99.
Alec Norton 《Proceedings of the American Mathematical Society》1999,127(10):3111-3118
If is the (unique) minimal set for a diffeomorphism of the circle without periodic orbits, , then the upper box dimension of is at least . The method of proof is to introduce the exponent into the proof of Denjoy's theorem.
100.
A numerical model to calculate the impulse response of a two-dimensional, impenetrable, rough surface directly in the time domain has been recently introduced [J. Acoust. Soc. Am. (2000) 107, 27]. This model is based on wedge diffraction theory and assumes that the half-space containing the source and receiver is homogeneous. In this work, the model is extended to handle media where the index of refraction varies with the distance to the surface by merging the scattering model with a ray-based propagation model. The resulting hybrid model is tested against a Finite-Difference Time-Domain (FDTD) method for the problem of backscattering from a corrugated surface in the presence of a refractive layer. This new model can be applied, for example, to calculate acoustic reverberation from the sea surface in cases where the water mass is inhomogeneous and in the presence of a subsurface bubble layer at low frequencies where dispersion is negligible. It can also be used for atmospheric propagation problems where there is a sound speed gradient overlying rough terrain. 相似文献