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排序方式: 共有287条查询结果,搜索用时 31 毫秒
281.
Shyamaprosad Goswami Subrata Jana Anita Hazra Avijit Kumar Adak 《Journal of heterocyclic chemistry》2007,44(5):1191-1194
282.
Quality of decisions in inventory management models depends on the accuracy of parameter estimates used for decision making. In many situations, error in decision making is unavoidable. In such cases, sensitivity analysis is necessary for better implementation of the model. Though the newsvendor model is one of the most researched inventory models, little is known about its robustness. In this paper, we perform sensitivity analysis of the classical newsvendor model. Conditions for symmetry/skewness of cost deviation (i.e., deviation of expected demand–supply mismatch cost from its minimum) have been identified. These conditions are closely linked with symmetry/skewness of the demand density function. A lower bound of cost deviation is established for symmetric unimodal demand distributions. Based on demonstrations of the lower bound, we found the newsvendor model to be sensitive to sub-optimal ordering decisions, more sensitive than the economic order quantity model. Order quantity deviation (i.e., deviation of order quantity from its optimum) is explored briefly. We found the magnitude of order quantity deviation to be comparable with that of parameter estimation error. Mean demand is identified as the most influential parameter in deciding order quantity deviation. 相似文献
283.
Ratul Chowdhury Ritabrata Biswas Nairwita Mazumder Subenoy Chakraborty 《International Journal of Theoretical Physics》2011,50(5):1628-1642
This paper deals in the thermodynamic properties of Einstein-Gauss-Bonnet and Einstein-Yang-Mills-Gauss-Bonnet black holes.
It exhibits the various stable and unstable phases of the black holes in these two modified gravity theories. In the first
section, that reveals the various aspects of Einstein-Gauss-Bonnet black holes, we chose to study the changes in the Hawking
Temperature with variations in the radius of event horizon (r) and charge (Q); and tried to justify them physically. Secondly in case of Einstein-Yang-Mills-Gauss-Bonnet black holes, we have attempted
to compare the changes in the various thermodynamic parameters with varying r and Q; with the Einstein-Gauss-Bonnet black holes at a macroscopic level. Here we have considered the Yang Mills tensor, electromagnetic
Lagrangian added to the action integrand. Again this very work deals in drawing out the similarities between these two types
of black holes, thereby throwing some light on the aspect of black hole stability. Later we have also introspected the effects
of the Gauss-Bonnet coupling parameter α, whose function (6αr), is added as a correction term to the black hole entropy. We have especially focused on what changes does it have upon the
nature of the plots as to whether it enhances or reduces the effect of Q on the behavior of the curves. Finally this paper has also kept an eye at estimating the stability domains of the black holes
described in these two gravity theories. 相似文献
284.
Ghosh RD Das S Ganguly A Banerjee K Chakraborty P Sarkar A Chatterjee M Nanda A Pradhan K Choudhuri SK 《Dalton transactions (Cambridge, England : 2003)》2011,40(41):10873-10884
Multiple drug resistance (MDR) remains a major clinical challenge for cancer treatment. P-glycoprotein is the major contributor and they exceed their role in the chemotherapy resistance of most of the malignancies. Attempts in several preclinical and clinical studies to reverse the MDR phenomenon by using MDR modulators have not yet generated promising results. In the present study, a co-ordination complex of zinc viz., Zn N-(2-hydroxyacetophenone)glycinate (ZnNG) has been synthesized, characterized and its antitumour activity was tested in vitro against drug sensitive and resistant human T-lymphoblastic leukemic cell lines (CCRF/CEM and CEM/ADR5000 respectively) and in vivo against Ehrlich ascites carcinoma (EAC) implanted in female Swiss albino mice. To evaluate the cytotoxic potential of ZnNG, we used sensitive CCRF/CEM and drug resistant CEM/ADR 5000 cell lines in vitro. Moreover, ZnNG also has the potential ability to reverse the multidrug resistance phenotype in drug resistant CEM/ADR 5000 cell line and induces apoptosis in combination with vinblastine. ZnNG remarkably increases the life span of Swiss albino mice bearing sensitive and doxorubicin resistant subline of EAC in presence and in absence of doxorubicin. In addition, intraperitoneal application of ZnNG in mice does not show any systemic toxicity in preliminary trials in normal mice. To conclude, a novel metal chelate of zinc viz., ZnNG, may be a promising therapeutic agent against sensitive as well as drug resistant cancers. 相似文献
285.
Avijit Chowdhury Narayan Banerjee 《The European Physical Journal C - Particles and Fields》2018,78(7):594
The quasinormal modes of charged and uncharged massive scalar fields and also of charged Dirac fields against the background of a charged spherical black hole endowed with a scalar hair have been investigated. Special emphasis has been given to the case where negative scalar charge dominates over the electric charge of the black hole which mimics an Einstein-Rosen bridge. Except for the complete monotonic behaviour of the damping (imaginary part of the quasinormal frequency) against the charge of the black hole as opposed to the existence of a peak for the pure Reissner-Nordström case, the qualitative behaviour does not appreciably change due to the presence of scalar hair. 相似文献
286.
Dr. Shaikh A. Ali Dr. Hasan A. Al-Muallem Dr. Mohammad A. J. Mazumder 《Chemical record (New York, N.Y.)》2023,23(2):e202200235
This article reviews the synthesis of polyzwitterions (PZs) (poly-carboxybetaines, -phosphonobetaines, and -sulfobetaines) having multiple pH-responsive centers. The synthesis follows the Butler cyclopolymerization protocol involving a multitude of diallylammonium salts and their copolymerization with SO2 and maleic acid. The PZs have been transformed into cationic-, anionic-polyelectrolytes, and polyampholytes under the influence of pH. Particular attention is given to the application of these polymers as antiscalants, mild steel corrosion inhibitors, components in constructing Aqueous Two-Phase Systems (ATPSs), and membrane modifiers. The ATPSs could be used to separate various biomolecules, including proteins. Many amphiphilic polymers incorporating a few mol % hydrophobic monomers have shown enhanced viscosities and could be suitable for applications in oil fields. The progress of applying Butler cyclopolymerization in reversible addition-fragmentation chain transfer (RAFT) chemistry has been discussed. Future works are expected to focus on RAFT cyclopolymerization to construct block copolymers. 相似文献
287.
Dr. Md Motiur Rahaman Mazumder Rezoanul Islam Dr. M. Azizur R. Khan Dr. K. M. Anis-Ul-Haque Prof. Dr. Mohammed M. Rahman 《化学:亚洲杂志》2023,18(1):e202201025
The temperature dependency of the electrochemical analysis of acetyl ferrocene (AcFc) and iron(III) acetylacetonate ([Fe(acac)3]) has been investigated for non-aqueous redox flow batteries (NARFBs). AcFc and [Fe(acac)3] were utilized as catholyte and anolyte species, respectively, in an electrochemical cell with a cell voltage of 1.41 V and Coulombic efficiencies >99% for up to 50 total cycles at room temperature (RT, 25 °C). Experiments with a rotating ring disk electrode (RRDE) indicate that the diffusion coefficient reduces with decreasing temperature from 25 °C to 0 °C, yet the overall storage capacity was higher than that of an aqueous redox flow battery (ARFBs). The electrochemical kinetic rate constant (k0) of AcFc was found to be greater than that of [Fe(acac)3]. However, the value of k0 was not affected by the variable temperature. 1H NMR investigations reveal that temperature change during battery trials did not occur in any structural modification. The obtained result demonstrates the suitability of this battery at low temperatures. 相似文献