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81.
We consider a single machine scheduling problem to minimize the weighted completion time variance. This problem is known to be NP-hard. We propose a heuristic and a lower bound based on job splitting and the Viswanathkumar and Srinivasan procedure. The test on more than 2000 instances shows that this lower bound is very tight and the heuristic yields solutions very close to optimal ones since the gap between the solution given by the heuristic and the lower bound is very small. 相似文献
82.
Nayereh Majd Jahangir Payamara Fariba Daliri 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(3):1-12
We have investigated the quantum phase transition in the ground state of collective Lipkin-Meshkov-Glick model (LMG model) subjected to decoherence due to its interaction, represented by a quantum channel, with an environment. We discuss the behavior of quantum and classical pair wise correlations in the system, with the quantumness of correlations measured by quantum discord (QD), entanglement of formation (EOF), measurement-induced disturbance (MID) and the Clauser-Horne-Shimony-Holt-Bell function (CHSH-Bell function). The time evolution established by system-environment interactions is assumed to be Markovian in nature and the quantum channels studied include the amplitude damping (AD), phase damping (PD), bit-flip (BF), phase-flip (PF), and bit-phase-flip (BPF) channels. One can identify appropriate quantities associated with the dynamics of quantum correlations signifying quantum phase transition in the model. Surprisingly, the CHSH-Bell function is found to detect all the phase transitions, even when quantum and classical correlations are zero for the relevant ground state. 相似文献
83.
Rick L. Paul Elizabeth A. Mackey Rolf Zeisler Rabia O. Spatz Bryan E. Tomlin 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(3):945-950
A combination of instrumental neutron activation analysis (INAA) and prompt gamma-ray activation analysis (PGAA) was used
to value assign 35 elements in SRM soil 2709a (San Joaquin Soil). INAA with counting of short-lived radioisotopes was used
for determination of Al, Au, Ca, Dy, K, Mg, Mn, Na, Ti, and V. Elements determined by INAA with counting of intermediate and
long-lived radioisotopes included As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Lu, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Yb, Zn, and
Zr. Thermal neutron PGAA was used for the determination of H, B, Si, K, Ti, Mn, Fe, Cd and Gd. Expanded uncertainties were
determined for all values reported. 相似文献
84.
MI Umar MZ Asmawi A Sadikun IJ Atangwho MF Yam R Altaf A Ahmed 《Molecules (Basel, Switzerland)》2012,17(7):8720-8734
This study evaluated the anti-inflammatory effect of Kaempferia galanga (KG) using an activity-guided approach. KG rhizomes were serially extracted with petroleum ether, chloroform, methanol and water. These extracts (2 g/kg each) were tested for their ability to inhibit carrageenan-induced rat paw edema. The chloroform extract was found to exert the highest inhibition (42.9%) compared to control (p < 0.001), hence it was further fractionated by washing serially with hexane, hexane-chloroform (1:1) and chloroform. The chloroform fraction (1 g/kg) showed the highest inhibitory effect (51.9%, (p < 0.001), on carrageenan-induced edema. This chloroform fraction was further fractionated with hexane-chloroform (1:3) and chloroform, and of the two fractions, the hexane-chloroform sub-fraction was the most effective in inhibiting edema (53.7%, p < 0.001). GC-MS analysis of the active sub-fraction identified ethyl-p-methoxycinnamate (EPMC) as the major component, which was re-crystallized. EPMC dose-dependently inhibited carrageenan-induced edema with an MIC of 100 mg/kg. Moreover, in an in vitro study, EPMC non-selectively inhibited the activities of cyclooxygenases 1 and 2, with IC?? values of 1.12 μM and 0.83 μM respectively. These results validate the anti-inflammatory activity of KG which may be exerted by the inhibition of cyclooxygenases 1 and 2. EPMC isolated from this plant may be the active anti-inflammatory agent. 相似文献
85.
Rabia Nessah 《Bulletin des Sciences Mathématiques》2004,128(5):417-431
An existence result for abstract nonlinear inequalities. As a consequence of our result, we obtain some further generalizations of recent known results. According to this result, we show the existence of g-saddle point and Aumann strong equilibrium for a constrained noncooperative game. 相似文献
86.
Rabia Sattar Rubina Mukhtar Muhammad Atif Muhammad Hasnain Ali Irfan 《Journal of heterocyclic chemistry》2020,57(5):2079-2107
The presence of benzoxazole moiety in most of the heterocyclic compounds is well reported. The present literature review mainly highlights the novel synthetic transformation and describes the biological potential of most of the heterocyclic compounds by virtue of presence of benzoxazole framework. Most of the researchers have revealed that benzoxazole derivatives exhibit significant antibacterial, anti-inflammatory, antifungal, anticancer, analgesic, antiviral, anti-tubercular, and anthelmintic activities. Benzoxazole moieties also act as tyrosinase inhibitor and cholesterol ester transfer protein inhibitor. This literature review may provide an opportunity to the chemists to design new derivatives of benzoxazole that proved to be the successful agent in view of safety, effectiveness, and efficacy. 相似文献
87.
Guanidino compounds guanidine, methylguanidine, guanidinoacetic acid, guanidinobutyric acid, guanidinopropionic acid, and guanidinosuccinic acid after derivatization with hexafluoroacetylacetone and ethyl chloroformate at pH 9 in aqueous phase, eluted, and separated from gas chromatographic column HP-5 (30 m × 0.32 mm id) with film thickness of 0.25 μm at an initial column temperature 90 °C for 2 min, followed by heating rate of 10 °C min?1 up to 220 °C with nitrogen flow rate of 1 mL min?1. The detection was by flame ionization detector. The linear calibration ranges of each of guanidino compounds were obtained within 1–10 μg mL?1, and the limit of detection was within 0.014–0.19 μg mL?1. The derivatization and gas chromatography elution and separation were repeatable in terms of retention time and peak height/peak area with relative standard deviation (RSD) (n = 4) within 1.7–2.9 % and 1.4–2.8 %, respectively. The method was applied for the determination of guanidino compounds from deproteinized serum of uremic patients and healthy volunteers, and was found in the range below the limit of quantitation (BLOQ) to 1.25 μg mL?1 with RSD within 1.4–3.6 %, and BLOQ to 0.4 μg mL?1 with RSD 1.3–3.4 %, respectively. A number of pharmaceutical additives did not effect the determination with RSD within ±3.1 %. 相似文献
88.
Nadia Parveen Rabia Nazir Muhammad Mazhar 《Journal of Thermal Analysis and Calorimetry》2013,111(1):93-99
Tris(bipyridine)nickel(II) chloride (1) and bis(bipyridine)nickel(II) chloride (2) pyrolize at heating rate of 50 °C/min to a maximum of 450 °C for 24 h under an inert atmosphere of flowing argon gas, to yield size-controlled nickel nanoparticles. Thermogravimetric studies of the complexes (1) and (2) and GC–MS analysis of the trapped volatile matter evolved during thermal degradation of the complexes indicate their clean decomposition pathway to zero-valent nickel. Both heating rate and argon gas flow rate affect purity, particle size, and shape of the particles. X-ray powder diffractometry and atomic force microscopy showed the formation of face-centered cubic (fcc) structured nickel particles having particle size in the range of 3.5–5.0 nm. Magnetic susceptibility measurements suggest nickel nanoparticles to be ferromagnetic in nature characterized by particle size–dependent Curie temperature and high coercivity that is comparable to the bulk iron. 相似文献
89.
90.
Sma?n Hocine Chérifa Rabia Mohammed M. Bettahar Michel Fournier 《Reaction Kinetics and Catalysis Letters》2003,79(2):357-364
Cs2.5M0.08H0.26PMo12O40and Cs2.5M0.08H1.26PMo11VO40(M: Ni, Fe) heteopolyanions were selectively prepared, characterized by IR, Raman, 31P NMR, XPS and XRD and tested in the ODH of cyclohexane. The salt structure, and reaction mechanism and kinetics are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献