This paper presents a new method for robust online variability extraction in time series. The proposed estimator is simultaneously highly robust and efficient. We derive its breakdown point, influence function, and asymptotic variance and study the finite sample properties in a simulation study. 相似文献
A simple and direct spectrophotometric method is developed for the determination of some cephalosporin group antibiotic drugs
such as Loracarbef (Lora), Ceftazidime (Ceft), and Cefaclor (Cefa) in bulk and pharmaceutical formulations. The optimum conditions
for the analysis of aqueous solutions of drugs are studied. Under the optimum conditions, the three drugs could be assayed
in the concentration range 2–9 × 10−5, 2–6 × 10−5, and 3–9 × 10−5 M for Lora, Ceft and Cefa, respectively. Detection and quantification limits are calculated. The obtained results showed
good recoveries of 100.4, 107.4, and 100.7% for Lora, Ceft, and Cefa, respectively. The results obtained are compared favorably
with those given by literature methods. 相似文献
This paper presents an eigenfunctions expansion based scheme for Fractional Optimal Control (FOC) of a 2-dimensional distributed
system. The fractional derivative is defined in the Riemann–Liouville sense. The performance index of a FOC problem is considered
as a function of both state and control variables, and the dynamic constraints are expressed by a Partial Fractional Differential
Equation (PFDE) containing two space parameters and one time parameter. Eigenfunctions are used to eliminate the terms containing
space parameters and to define the problem in terms of a set of generalized state and control variables. For numerical computation
Grünwald–Letnikov approximation is used. A direct numerical technique is proposed to obtain the state and the control variables.
For a linear case, the numerical technique results into a set of algebraic equations which can be solved using a direct or
an iterative scheme. The problem is solved for different number of eigenfunctions and time discretization. Numerical results
show that only a few eigenfunctions are sufficient to obtain good results, and the solutions converge as the size of the time
step is reduced. 相似文献
Pyridine-derived platinum(II) complexes with the general formula [PtCl2L2] (L1: 3,5-dimethylpyridine, L2: 2-amino-5-bromopyridine, L3: 4-(4-nitrobenzyl)pyridine) were synthesized. Characterization of the synthesized complexes was made via FT-IR, UV–Vis, 1H-NMR and 13C-NMR techniques. While the thermal behavior of the complexes was investigated via DTA/TG combined system, their kinetic parameters were investigated by using Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods. The activation energy of the decomposition kinetics of the complexes was calculated to be 196.5–31.7 kJ mol?1 for FWO and 203.4–29.2 kJ mol?1 for KAS. The cytotoxic effect of the complexes against the colon cancer cell line (DLD-1), which is one of the most common types of cancer observed both in humans and animals, was investigated. The complexes showed high cytotoxicity on DLD-1. In particular, [PtCl2L12] complex was found to be the most effective compounds against colon cancer cell line during the 24 h incubation period. According to these results, the pyridine-derived platinum(II) complexes would contribute to oncologic treatment as chemotherapeutic agents.
Triple diamino-bridged cyclotriphosphazene (1) was reacted in a 1:8 stoichiometry with the sodium derivatives of long-chain diols [1-octanol, 1-decanol, 1-dodecanol, 1-hexadecanol] tetrahydrofuran (THF) at room temperature to form hexa-substituted cyclotriphosphazene derivatives (2, 3, 4 and 5, respectively), whose mesomorphic behaviours were investigated for their possible applications as liquid crystals. The cylindrical-type cyclotriphosphazene derivatives (2–5) were characterised by mass and elemental analyses and by Fourier transform infrared spectroscopy (FT-IR), 1H and 31P {1H} NMR spectroscopies. The thermal and mesomorphic properties were investigated by differential scanning calorimetry and by polarising optical microscopy, respectively. It was found that liquid crystal materials could be obtained from compounds 3 and 4 with alkoxy chains rather than using aromatic ring(s) as mesogens as published previously. 相似文献
AbstractWe study the transfer via functors between abelian categories of the (dual) relative splitness of objects with respect to a fully invariant short exact sequence. We mainly consider fully faithful functors and adjoint pairs of functors. We deduce applications to Grothendieck categories, (graded) module categories and comodule categories. 相似文献
Reaction of cyclophosphazene, N3P3Cl6 (1), with the sodium derivative of the fluorinated diol, 2,2,3,3,4,4-hexafluoropentane-1,5-diol (2), in THF solution at room temperature afforded five isolated products, whose structures have been characterised by X-ray crystallography and 1H, 19F and 31P NMR spectroscopy: the mono-spiro compound, N3P3Cl4(OCH2CF2CF2CF2CH2O) (3), its ansa isomer (4), a di-spiro derivative N3P3Cl2(OCH2CF2CF2CF2CH2O)2 (5), its spiro-ansa (6) isomer and the tri-spiro compound N3P3(OCH2CF2CF2CF2CH2O)3 (7). Quantitative 31P NMR measurements of the soluble portion of the reaction mixture show that in the reaction of (1) with the sodium derivative of the fluorinated pentanediol (2) there is a small preference for spiro compounds compared to ansa compounds (ratio ca. 1.3:1), similar to the analogous reaction of (1) with the sodium derivative of the fluorinated butanediol where there is a slightly greater proportion of spiro compared to ansa compounds (ratio ca. 1.5:1). The relative proportions of spiro and ansa compounds is likely to depend on the fine balance in stabilities of the different medium-sized rings in the fluorinated pentanediol (spiro, 8- and ansa, 10-membered rings) compared to the fluorinated butanediol (spiro, 7- and ansa, nine-membered rings) derivatives of cyclophosphazene. 相似文献
The TiO2 nanoparticles are electrospun with polyacrylonitrile (PAN) polymer solution onto the discharged battery coal (DBC) electrode and the results are evaluated as a supercapacitor. The morphology and chemical composition of the synthesized TiO2 nanoparticles and PAN+TiO2 nanocomposite fibers were characterized by Scanning electron microscopy, thermogravimetry and FTIR analysis. Supercapacitor measurements and electrochemical characterizations of the electrodes examined by cyclic voltammetry and electrochemical impedance spectroscopy. Electrochemical measurements showed that the best current value was obtained from PAN and TiO2 coated DBC. The performances of both PAN and PAN+TiO2 coated DBC electrodes were investigated as supercapacitors. PAN+TiO2/DBC showed the best specific capacitance value of 156.00 F g−1 and PAN/DBC showed 74.93 F g−1. In addition, PAN+TiO2/DBC exhibited reliable stability performance over 2000.00 cycles. 相似文献
In this work, an electrochemical DNA‐based sensor was developed for the detection of the interaction between the anticonvulsant compounds 2‐phthalimido‐N‐substituted phenylethanesulfonamides (PMPES‐derivatives) and 24‐mer short DNA sequences by using differential pulse voltammetry (DPV) based on both compound and guanine oxidation signals at the renewable carbon graphite electrode (CGE) surface. The influence of compounds on DNA showed differences depending on the nature and position of the substituent on the N‐phenyl ring. Compounds bearing 3‐methoxy, 4‐chloro and 2,6‐dimethyl substituents bind to single stranded probe DNA more strongly than the other derivatives of PMPES. Thus, these compounds were evaluated for use as an electrochemical hybridization label (indicator). 相似文献