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Nonlinear Dynamics - Inclusion of redundancy has been one of the primary techniques to reduce the probability of error and to achieve reliability in computing systems and many other engineered... 相似文献
43.
We investigate the effects of final state interactions (FSI) contributions in the nonleptonic two body $B^ + \to D_S^ + \bar K^0$ decay, however the hadronic decay of $B^ + \to D_S^ + \bar K^0$ is analyzed by using “QCD factorization” (QCDF) method and final state interaction (FSI). First, the $B^ + \to D_S^ + \bar K^0$ decay is calculated via QCDF method and only the annihilation graphs exist in that method. Hence, the FSI must be seriously considered to solve the $B^ + \to D_S^ + \bar K^0$ decay and the D 0π+(D 0*ρ+), D +π0(D +*ρ0) and D +η c (D +*J/ψ) via the exchange of K +(*), K 0(*) and D s +(*) mesones are chosen for the intermediate states. To estimate the intermediate states amplitudes, the QCDF method is again used. These amplitudes are used in the absorptive part of the diagrams. The experimental branching ratio of $B^ + \to D_S^ + \bar K^0$ decay is less than 8 × 10?4 and the predicted branching ratio is 0.23 × 10?9 in the absence of FSI effects and it becomes 6.74 × 10?4 when FSI contributions are taken into account. 相似文献
44.
Katherine G. Young Behnam Najafi William M. Sant Sonia Contera Ard A. Louis Jonathan P. K. Doye Andrew J. Turberfield Jonathan Bath 《Angewandte Chemie (International ed. in English)》2020,59(37):15942-15946
DNA self‐assembly allows the construction of nanometre‐scale structures and devices. Structures with thousands of unique components are routinely assembled in good yield. Experimental progress has been rapid, based largely on empirical design rules. Herein, we demonstrate a DNA origami technique designed as a model system with which to explore the mechanism of assembly. The origami fold is controlled through single‐stranded loops embedded in a double‐stranded DNA template and is programmed by a set of double‐stranded linkers that specify pairwise interactions between loop sequences. Assembly is via T‐junctions formed by hybridization of single‐stranded overhangs on the linkers with the loops. The sequence of loops on the template and the set of interaction rules embodied in the linkers can be reconfigured with ease. We show that a set of just two interaction rules can be used to assemble simple T‐junction origami motifs and that assembly can be performed at room temperature. 相似文献
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HazemShabaBehnam G.S.Srivastava 《逼近论及其应用》2002,18(3):1-14
We consider the space X of all analytic functions f(s1,s2)=∑∞m,n=1 amnexp(s1λm s2μn) of two complex variables s1 and s2,equipping it with the natural locally convex topology and using the growth parameter,the order of f as defined recently by the authors.Under this topology X becomes a Frechet space.Apart from finding the characterization of continuous linear functionals,linear transformation on X,we have obtained the necessary and sufficient conditions for a double sequence in X to be a proper bases. 相似文献
47.
Headspace-solvent microextraction (HS–SME) with sample ultrasound irradiation was successfully used for the study of the influence
of nitrogen fertilization and plant density on the essential oil yield and composition of cumin (Cuminum cyminum L.) seeds. The components were collected into a single microdrop of n-heptadecane and directly injected into a GC–MS injection port for analysis. A simplex method was used for fast optimization
of the extraction parameters. The experiments were executed as split-plot based on randomized complete block design. Nitrogen
fertilization as the main factor (in four levels) and plant density as subsidiary factor (in three levels) were applied. It
was shown that the total GC peak areas of the HS–SME extract, is proportional to the essential oil yield of the cumin seeds
obtained by a hydrodistillation method. Furthermore, similar trends in the concentrations of cuminaldehyde and most other
volatile components were obtained by the two methods. 相似文献
48.
Nano‐structured gemini‐based supramolecular solvent for the microextraction of cyhalothrin and fenvalerate 下载免费PDF全文
Neda Feizi Yadollah Yamini Morteza Moradi Behnam Ebrahimpour 《Journal of separation science》2016,39(17):3400-3409
A novel supramolecular solvent‐based microextraction followed by high‐performance liquid chromatography with ultraviolet detection method has been developed for the extraction and determination of two pyrethroid analytes, cyhalothrin and fenvalerate, in water and soil samples. The liquid–liquid‐phase separation of surfactants has been used in analytical extraction. The surfactant‐rich phase is a nano‐structured liquid, recently named as a supramolecular solvent, generated from the amphiphiles. The alkyl carboxylic acid based supramolecular solvents were introduced before. Coacervates made up of gemini surfactant, consisting of two amphiphilic moieties, were first used as solvent. The effective parameters on extraction (i.e., type of organic solvent, the amount of surfactant and volume of tetrahydrofuran, sample solution pH, salt addition, ultrasonic and centrifugation time) were investigated and optimized. Under the optimum conditions, preconcentration factors of 110 and 145 were obtained for the analytes. The linearity was 0.5–200.0 μg/L with the correlation of determination of (R2) ≥ 0.9984. The limit of detection of the method was (S/N = 3) 0.2 μg/L, and precisions in the range of 6.3–10.3% (RSDs, n = 5) were obtained. This method has been successfully applied to analyze real samples, and good recoveries in the range of 101.2–108.8% were obtained. 相似文献
49.
The aim of the present work is combination of the advantages of magnetic solid phase extraction (MSPE) and dispersive liquid phase microextraction (DLLME) followed by filtration-based phase separation. A new pretreatment method was developed for trace determination of megestrol acetate and levonorgestrel by liquid chromatography/ultraviolet detection in biological and wastewater samples. After magnetic solid phase extraction, the eluent of MSPE was used as the disperser solvent for DLLME. Emulsion resulted from DLLME procedure was passed through the in-line filter for phase separation. Finally the retained analytes in the filter was washed with mobile phase of liquid chromatography and transferred to the column for separation. This approach offers the preconcentration factors of 3680 and 3750 for megestrol acetate and levonorgestrel, respectively. This guarantees determination of the organic compounds at trace levels. The important parameters influencing the extraction efficiency were studied and optimized. Under the optimal extraction conditions, a linear range of 0.05–50 ng mL−1 (R2 > 0.998) and limit of detection of 0.03 ng mL−1 were obtained for megestrol acetate and levonorgestrel. Under optimal conditions, the method was successfully applied for determination of target analytes in urine and wastewater samples and satisfactory results were obtained (RSDs < 6.8%). 相似文献
50.