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排序方式: 共有274条查询结果,搜索用时 15 毫秒
1.
Physics of Atomic Nuclei - In this work we derive analytically a real $$\alpha+\alpha$$ potential using the JLM effective nucleon–nucleon (NN) interaction. The aim is to obtain analytically... 相似文献
2.
Synthesis of Nanoporous Ni‐Co Mixed Oxides by Thermal Decomposition of Metal‐Cyanide Coordination Polymers 下载免费PDF全文
Mohamed B. Zakaria Dr. Ming Hu Dr. Malay Pramanik Dr. Cuiling Li Dr. Jing Tang Prof. Ali Aldalbahi Prof. Saad M. Alshehri Dr. Victor Malgras Prof. Yusuke Yamauchi 《化学:亚洲杂志》2015,10(7):1541-1545
A straightforward strategy to prepare nanoporous metal oxides with well‐defined shapes is highly desirable. Through thermal treatment and a proper selection of metal‐cyanide coordination polymers, nanoporous nickel‐cobalt mixed oxides with different shapes (i.e., flakes and cubes) can be easily prepared. Our nanoporous materials demonstrate high electrocatalytic activity for oxygen evolution reaction. 相似文献
3.
Chanjuan Zhang Dr. Philipp Gotico Dr. Regis Guillot Dr. Diana Dragoe Dr. Winfried Leibl Dr. Zakaria Halime Prof. Ally Aukauloo 《Angewandte Chemie (International ed. in English)》2023,62(8):e202300926
At the core of carbon monoxide dehydrogenase (CODH) active site two metal ions together with hydrogen bonding scheme from amino acids orchestrate the interconversion between CO2 and CO. We have designed a molecular catalyst implementing a bimetallic iron complex with an embarked second coordination sphere with multi-point hydrogen-bonding interactions. We found that, when immobilized on carbon paper electrode, the dinuclear catalyst enhances up to four fold the heterogeneous CO2 reduction to CO in water with an improved selectivity and stability compared to the mononuclear analogue. Interestingly, quasi-identical catalytic performances are obtained when one of the two iron centers was replaced by a redox inactive Zn metal, questioning the cooperative action of the two metals. Snapshots of X-ray structures indicate that the two metalloporphyrin units tethered by a urea group is a good compromise between rigidity and flexibility to accommodate CO2 capture, activation, and reduction. 相似文献
4.
Rahmawati Rahmawati Yeni Wahyuni Hartati Jalifah binti Latip Tati Herlina 《Journal of separation science》2023,46(12):2200800
Plants in the genus Erythrina is a potential source of chemical constituents, one of which is flavonoids, which have diverse bioactivities. To date, literature on the flavonoids from the genus Erythrina has only highlighted the phytochemical aspects, so this review article will discuss isolation techniques and strategies for the first time. More than 420 flavonoids have been reported in the Erythrina genus, which are grouped into 17 categories. These flavonoid compounds were obtained through isolation techniques and strategies using polar, semi-polar, and non-polar solvents. Various chromatographic techniques have been developed to isolate flavonoids using column flash chromatography, quick column chromatography, centrifugally accelerated thin-layer chromatography, radial chromatography, medium-pressure column chromatography, semi-preparative high-performance liquid chromatography, and preparative high-performance liquid chromatography. Chromatographic processes for isolating flavonoids can be optimized using multivariate statistical applications such as response surface methodology with central composite design, Box–Behnken design, Doehlert design, and mixture design. 相似文献
5.
In this Note, a numerical investigation of laminar convection wake above a heated plate placed in a channel is carried out. An analytical study based on a three region structure is proposed in the immediate neighbourhood of the trailing edge. Velocity and temperature at the centerline channel as well as the pressure gradient are presented in asymptotic expressions. Comparison of these results with numerical solutions enhances the analytical study. To cite this article: Z. Doulfoukar, A. Achiq, C. R. Mecanique 333 (2005). 相似文献
6.
Zakaria Belhachmi Christine Bernardi Andreas Karageorghis 《Journal of Mathematical Fluid Mechanics》2004,6(2):121-156
This paper deals with the spectral element discretization
of the Navier-Stokes equations in a disk with discontinuous
boundary data, which is known as the driven cavity problem.
The numerical treatment does not involve any
regularization of these data. Relying on a variational
formulation in the primitive variables of
velocity and pressure, we describe a discretization of these equations and
derive error estimates in appropriate weighted Sobolev spaces.
We propose an algorithm to solve the
nonlinear discrete system and present numerical experiments to verify its
efficiency. 相似文献
7.
Zuriati Zakaria 《中国化学会会志》2020,67(12):2241-2245
This article reflects on the Federation of Asian Chemical Societies (FACS) Citation Award Lecture delivered in the Industrial Technology Research Institute Symposium on CO2 Utilization and Green Technology during the 18th Asian Chemical Congress held in Taipei, December 12, 2019. Malaysia produces sizable amounts of palm oil and palm kernel oil, with palm fronds and tree trunks as the main waste. At the Malaysia Japan International Institute of Technology, the biomass was decomposed to produce fine chemicals, used as substrate for mushroom growth, and converted to bio-coke for heat energy. A notable difference has been found regarding the emission of greenhouse gases from a natural peat forest and those from the oil palm plantation converted from peatlands, where in the palm plantation, water table is lowered and aerobic processes occurs, resulting in more CO2 being released compared to CH4. The introduction of fertilizers to the plantation resulted in more N2O being released. The team has also pioneered a project to plant temperate vegetables. Cooling pipes (16–18°C with circulating water cooled by chiller) were embedded within each thermal conditioning soil plot. Lettuce and radish, the experimental plants, showed good growth in the thermal conditioning soil due to nitrogen-fixing bacteria, which were destroyed at a higher temperature. 相似文献
8.
Zakaria Zoukal 《Journal of Macromolecular Science: Physics》2020,59(10):621-634
AbstractThe role of the end-groups of three oligophenylene vinylene (OPV) and the solvents on the hybrid materials from poly (vinyl chloride) (PVC) and the OPV are examined. The gelation of the three organogel OPVs and of the hybrid materials in bromobenzene and benzyl alcohol was characterized. The morphology, as well as the thermodynamic properties, of these OPV and hybrid materials showed that they depended mostly on the solvent and very little on the different end-groups located on the OPV backbones. 相似文献
9.
Qinghua Cai Zakaria Mohamad Yuan Yuan 《Communications in Nonlinear Science & Numerical Simulation》2012,17(12):4856-4869
We propose two nutrient-phytoplankton models with instantaneous and time delayed recycling, investigate the dynamics and examine the responses to model complexities. Instead of the familiar specific uptake rate and growth rate functions, we assume only that the nutrient uptake and phytoplankton growth rate functions are positive, increasing and bounded above. We use geometrical and analytical methods to find conditions for the existence of none, one, or at most two positive steady states and analyze the stability properties of each of these equilibria. With the variation of parameters, the system may lose its stability and bifurcation may occur. We study the occurrence of Hopf bifurcation and the possibility of stability switching. Numerical simulations illustrate the analytical results and provide further insight into the dynamics of the models, biological interpretations are given. 相似文献
10.
Jost Klawitter Stephan Bek Marjorie Zakaria Chenhui Zeng Andrea Hornberger Richard Gilbert Touraj Shokati Jelena Klawitter Uwe Christians K. Olaf Boernsen 《Analytical and bioanalytical chemistry》2014,406(25):6399-6408
Stearoyl-CoA desaturase 1 (SCD1) plays a role in the development of obesity and related conditions, such as insulin resistance, and potentially also in neurological and heart diseases. The activity of SCD1 can be monitored using the desaturation index (DI), the ratio of product (16:1n-7 and 18:1n-9) to precursor (16:0 and 18:0) fatty acids. Here, different analytical strategies were applied to identify the method which best supports SCD1 biology. A novel effective approach was the use of the SCD1-independent fatty acid (16:1n-10) as a negative control. The first approach was based on a simple extraction followed by neutral loss triglyceride fatty acid analysis. The second approach was based on the saponification of triglycerides followed by fatty acid analysis (specific for the position of the double bond within monounsaturated fatty acids (MUFAs)). In addition to the analytical LC-MS assays, different matrices (plasma total triglyceride fraction and the very low-density lipoprotein (VLDL) fraction) were investigated to identify the best for studying changes in SCD1 activity. Samples from volunteers on a high-carbohydrate diet were analyzed. Both ultra HPLC (UHPLC)-MS-based assays showed acceptable accuracies (75–125 % of nominal) and precisions (<20 %) for the analysis of DI-specific fatty acids in VLDL and plasma. The most specific assay for the analysis of the liver SCD activity was then validated for specificity and selectivity, intra- and interday accuracy and precision, matrix effects, dilution effects, and analyte stability. After 3 days of high-carbohydrate diet, only the specific fatty acids in human plasma VLDL showed a significant increase in DI and associated SCD1 activity. 相似文献