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11.
It is shown that the lower bound in the uncertainty relation for joint position-momentum measurements is twice as large as that in the usual Heisenberg uncertainty principle for separate measurements. 相似文献
12.
Compoundl, Cp2Mo(mto) is obtained by the reaction of Cp2MoCl2 with methanol solutions of potassium dithiooxalate in air. Red platelike crystals of Cp2Mo(mto) were grown by the slow diffusion of pentane into a CH2Cl2 solution ofl and have been studied by X-ray crystallography: space group, P21/n,a=7.578(1),b=10.551(2),c=14.090(3) Å, =94.38(2)°,V=1123.1(4) Å3,Z=4. The mto ligand chelates to the Mo atom through one oxygen atom and the sulfur atom. The two Cp rings form dihedral angles of 24° with the least-squares plane of the mto ligand. The Mo–O and Mo–S bond distances are 2.193(5) and 2.449(2) Å, respectively. 相似文献
13.
Ian H. Campbell John P. Ferraris Thomas W. Hagler Michael D. Joswick Ian D. Parker Darryl L. Smith 《先进技术聚合物》1997,8(7):417-423
A widely applicable electroabsorption technique to measure internal electric fields in organic light-emitting diodes is presented. The technique exploits the change in the a.c. electroabsorption response in the presence of a d.c. electric field. The electroabsorption signal is modulated at the fundamental frequency of the a.c. test signal, in addition to the usual modulation at the second harmonic frequency, when a d.c. bias is present. In metal/organic film/metal devices employing different metal contacts there is a built-in electric field in the organic film caused by the difference in work function between the two contacts. The electroabsorption response at the fundamental frequency of the applied a.c. bias is measured as a function of an external d.c. bias. The electroabsorption signal is nulled when the applied d.c. bias cancels the built-in electric field established by the different metals. We apply this technique to measure changes in metal–polymer Schottky barrier heights as a function of the contact metal. In metal/multiple organic films/metal structures the electroabsorption signals from the constituent organic films are identified spectroscopically and measured at both the fundamental and second harmonic frequency of the a.c. test signal. The amplitudes of the electroabsorption responses are then used to determine the a.c. and d.c. electric fields present in the organic layers. We apply this technique to determine the d.c. electric field distribution within a multi-layer organic light-emitting diode. These results highlight the general applicability of electroabsorption methods to probe internal electric fields in organic light-emitting diodes. © 1997 John Wiley & Sons, Ltd. 相似文献
14.
It is shown that the cone of positive normal functionals on a hypergraphA may be substantially larger than the cone of positive weights onA. For a semiclassical hypergraphA the two cones coincide if and only if the number of edges ofA of cardinality 2 is finite. This disproves an earlier statement of T. A. Cook. 相似文献
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16.
Johansson AS Whitaker TB Hagler WM Giesbrecht FG Young JH Bowman DT 《Journal of AOAC International》2000,83(5):1264-1269
The variability associated with testing lots of shelled corn for aflatoxin was investigated. Eighteen lots of shelled corn were tested for aflatoxin contamination. The total variance associated with testing shelled corn was estimated and partitioned into sampling, sample preparation, and analytical variances. All variances increased as aflatoxin concentration increased. With the use of regression analysis, mathematical expressions were developed to model the relationship between aflatoxin concentration and the total, sampling, sample preparation, and analytical variances. The expressions for these relationships were used to estimate the variance for any sample size, subsample size, and number of analyses for a specific aflatoxin concentration. Test results on a lot with 20 parts per billion aflatoxin using a 1.13 kg sample, a Romer mill, 50 g subsamples, and liquid chromatographic analysis showed that the total, sampling, sample preparation, and analytical variances were 274.9 (CV = 82.9%), 214.0 (CV = 73.1 %), 56.3 (CV = 37.5%), and 4.6 (CV = 10.7%), respectively. The percentage of the total variance for sampling, sample preparation, and analytical was 77.8, 20.5, and 1.7, respectively. 相似文献
17.
Five 2 kg test samples were taken from each of 120 farmers' stock peanut lots contaminated with aflatoxin. Kernels from each 2 kg sample were divided into the following U.S. Department of Agriculture grade components: sound mature kernels plus sound splits (SMKSS), other kernels (OK), loose shelled kernels (LSK), and damaged kernels (DAM). The kernel mass (g), aflatoxin mass (ng), and aflatoxin concentration (ng of aflatoxin/g of peanuts) were measured for each of the 2400 component samples. The variabilities associated with measuring aflatoxin mass (ng) in OK + LSK + DAM, or A(OLD)ng, and in LSK + DAM, or A(LD)ng, and aflatoxin concentration (ng/g) in OK + LSK + DAM, or A(OLD)ng/g, and in LSK + DAM, or A(LD)ng/g, were determined. The variance associated with measuring aflatoxin in each of the 4 combinations of components increased with aflatoxin, and functional relationships were developed from regression analysis. The variability associated with estimating the lot concentration from each of the 4 combinations of components was also determined. The coefficients of variation (CV) associated with estimating the aflatoxin for a lot with aflatoxin at 100 ng/g were 90, 86, 94 and 96% for aflatoxin masses A(OLD)ng and A(LD)ng and aflatoxin concentrations A(OLD)ng/g and A(LD)ng/g, respectively. The performance of aflatoxin sampling plans using the combination of aflatoxin masses in OK + LD + DAM and LD + DAM components was evaluated with a 2 kg test sample and a 50 ng/g accept/reject limit. 相似文献
18.
D. T. Nguyen A. C. Scheiner J. W. Andzelm S. Sirois D. R. Salahub A. T. Hagler 《Journal of computational chemistry》1997,18(13):1609-1631
The potential energy surface of un-ionized glycine has been explored with density functional theory. The performance of several nonlocal functionals has been evaluated and the results are presented in the context of available experimental information and post-Hartree–Fock quantum chemical results. The zero-point and thermal vibrational energies along with vibrational entropies play a very important role in determining the relative stability of glycine conformers; the realization of this has led to some revision and reinterpretation of the experimental results. Uncertainties in the vibrational contributions to the energy differences of several tenths of a kilocalorie/mole remain. The uncertainty in the vibrational free energy is even larger, about 1 kcal/mol. In the final analysis, we suggest that the best estimate of the electronic energy difference between the two lowest glycine conformers should be revised downward from 1.4 to 1.0 kcal/mol. Thirteen stationary points on the potential energy surface have been localized. For the majority of these, there is close agreement among various nonlocal density functionals and the post-Hartree–Fock methods. However, the second conformer (IIn), which has a strong hydrogen bond between the hydroxyl hydrogen and the nitrogen of the amine group, presents a distinct challenge. The relative energy of this conformer is extremely sensitive to the basis set, the level of correlation, or the functional used. The widely used BP86, PP86, and BP91 nonlocal functionals overestimate the strength of the hydrogen bond and predict that this conformer is the lowest energy structure. This contradicts both experiment and high-level post-Hartree–Fock studies. The adiabatic connection method (ACM) and the BLYP functional yield the correct order. The ACM method, in particular, gives energies which are in reasonable agreement with MP2, although these are somewhat low as compared with experiment. Based on this study, ACM should perform well for this type of bioorganic application, with typical errors of a few tenths of a kilocalorie/mole and only rarely exceeding 0.5 kcal/mol. © 1997 John Wiley & Sons, Inc. J Comput Chem 18 : 1609–1631, 1997 相似文献
19.
S. Besseghini A. Gambardella V. A. Chernenko M. Hagler C. Pohl P. Müllner M. Ohtsuka S. Doyle 《The European physical journal. Special topics》2008,158(1):179-185
A series of Ni51.4Mn28.3Ga20.3/Si(100) thin film composites with different film thicknesses varying from 0.1 to 5 μm have been prepared by magnetron sputtering
and subsequently annealed. X-ray powder diffraction patterns of the films show the features associated with the lattice-modulated
martensitic phase and/or cubic austenite at room temperature. 220-fiber texture was confirmed by the X-rays measurements made
at 150 °C. While the Curie temperature is almost film thickness independent, the martensitic transformation temperature shows
a strong descended dependence in the submicron range. The substrate curvature measurements demonstrate that the forward and
reverse martensitic transformation in the films is accompanied by the reversible relaxation and accumulation of residual stress,
originally created by the thermal treatment due to the difference in thermal expansion of the film and substrate. The values
of residual stresses measured by both substrate curvature and X-rays diffraction methods at constant temperatures are found
to be dependent on the film thickness. This behavior appears in correlation with the thickness dependence of the transformation
temperature. 相似文献
20.
Huang D Gu Q Ge H Ye J Salam NK Hagler A Chen H Xu J 《Journal of chemical information and modeling》2012,52(5):1356-1366
Human chemokine receptor CXCR3 (hCXCR3) antagonists have potential therapeutic applications as antivirus, antitumor, and anti-inflammatory agents. A novel virtual screening protocol, which combines pharmacophore-based and structure-based approaches, was proposed. A three-dimensional QSAR pharmacophore model and a structure-based docking model were built to virtually screen for hCXCR3 antagonists. The hCXCR3 antagonist binding site was constructed by homology modeling and molecular dynamics (MD) simulation. By combining the structure-based and ligand-based screenings results, 95% of the compounds satisfied either pharmacophore or docking score criteria and would be chosen as hits if the union of the two searches was taken. The false negative rates were 15% for the pharmacophore model, 14% for the homology model, and 5% for the combined model. Therefore, the consistency of the pharmacophore model and the structural binding model is 219/273 = 80%. The hit rate for the virtual screening protocol is 273/286 = 95%. This work demonstrated that the quality of both the pharmacophore model and homology model can be measured by the consistency of the two models, and the false negatives in virtual screening can be reduced by combining two virtual screening approaches. 相似文献