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排序方式: 共有207条查询结果,搜索用时 31 毫秒
21.
Redondo Mara Julia Romn Lucrecia Rossi Bertone Fiorela Verdecchia Melina 《Algebras and Representation Theory》2022,25(4):1037-1059
Algebras and Representation Theory - Let A and B be two Morita equivalent finite dimensional associative algebras over a field . It is well known that Hochschild cohomology is... 相似文献
22.
Fathy Abdel‐Kader Amer Metwally Hammouda Bakr Fathy Abdel‐Wahab Abdel‐Aziz Sayed El‐Ahl 《Journal of heterocyclic chemistry》2008,45(6):1549-1569
23.
Typical conversion of lignocellulosic biomass into reducing sugars using dilute acid hydrolysis and alkaline pretreatment 总被引:2,自引:0,他引:2
Yu-Loong Loow Ta Yeong Wu Jamaliah Md. Jahim Abdul Wahab Mohammad Wen Hui Teoh 《Cellulose (London, England)》2016,23(3):1491-1520
The development and production of fossil fuel alternatives have become one of the main focal points in recent investigations. Lignocellulosic biomass is a renewable source of fermentable sugars for second-generation biofuels and chemicals via biotechnological pathways. However, the presence of lignin and hemicellulose in lignocellulosic biomass makes it difficult for the biomass to be hydrolyzed or digested during fermentation. Thus, effective biomass pretreatment is vital. The present review shows that chemical pretreatment is the current preferred method to obtain high sugar yields at low cost, with dilute acid and alkaline hydrolysis as the two most reported technologies. Dilute acid favours hydrolysis of the hemicelluloses whereas alkaline hydrolysis targets the lignin fraction. Both methods have merits and demerits, and have been combined with other treatments such as hydrothermal and enzymatic hydrolysis. Further investigation is required to improve the pretreatment processes and to ensure the economic viability of bioconversion. 相似文献
24.
A.?Arhrib R.?BenbrikEmail author Chuan-Hung?Chen Melina?Gomez-Bock Souad?Semlali 《The European Physical Journal C - Particles and Fields》2016,76(6):328
We study the constraints of the generic two-Higgs-doublet model (2HDM) type-III and the impacts of the new Yukawa couplings. For comparisons, we revisit the analysis in the 2HDM type-II. To understand the influence of all involving free parameters and to realize their correlations, we employ a \(\chi \)-square fitting approach by including theoretical and experimental constraints, such as the S, T, and U oblique parameters, the production of standard model Higgs and its decay to \(\gamma \gamma \), \(WW^*/ZZ^*\), \(\tau ^+\tau ^-\), etc. The errors of the analysis are taken at 68, 95.5, and \(99.7~\%\) confidence levels. Due to the new Yukawa couplings being associated with \(\cos (\beta -\alpha )\) and \(\sin (\beta -\alpha )\), we find that the allowed regions for \(\sin \alpha \) and \(\tan \beta \) in the type-III model can be broader when the dictated parameter \(\chi _F\) is positive; however, for negative \(\chi _F\), the limits are stricter than those in the type-II model. By using the constrained parameters, we find that the deviation from the SM in \(h\rightarrow Z\gamma \) can be of \(\mathcal{O}(10~\%)\). Additionally, we also study the top-quark flavor-changing processes induced at the tree level in the type-III model and find that when all current experimental data are considered, we get \(Br(t\rightarrow c(h, H) )< 10^{-3}\) for \(m_h=125.36\) and \(m_H=150\) GeV, and \(Br(t\rightarrow cA)\) slightly exceeds \(10^{-3}\) for \(m_A =130\) GeV. 相似文献
25.
Roumaissa Zenzen Idir Belaidi Samir Khatir Magd Abdel Wahab 《Comptes Rendus Mecanique》2018,346(12):1253-1266
In this paper, a Structural Health Monitoring (SHM) technique for damage identification in beam-like and truss structures using Frequency Response Function (FRF) data coupled with optimization techniques is presented. Genetic Algorithm (GA) and Bat Algorithm (BA) are used to estimate the location and severity of damage. The damage in the structures is simulated by reduction in rigidity of specific members. Both optimization techniques are coupled with modelled structures using Finite Element Method (FEM). The approach is based on minimizing an objective function by comparing measured and calculated FRFs. The results show that better accuracy is obtained using BA than using GA in terms of precision and computational time. Furthermore, it is found that the proposed approach provides faster solution than other approaches in the literature. 相似文献
26.
Chitosan loaded with silver nanoparticles,CS‐AgNPs,using thymus syriacus,wild mint,and rosemary essential oil extracts as reducing and capping agents
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Fadi AL‐Shnani Thanaa Al‐Haddad Francois Karabet Abdul Wahab Allaf 《Journal of Physical Organic Chemistry》2017,30(11)
The present study describes the green method for the preparation of chitosan loaded with silver nanoparticles (CS‐AgNPs) in the presence of 3 different extracted essential oils. The essential oils play dual roles as reductant and capping agents. The reducing power and DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) assay for the 3 essential oils—Thymus syriacus (T), wild mint (M), and rosemary (R)—have been reported. The preparation of CS‐AgNPs was performed by 2 steps. The 3 previously extracted essential oils have been used as reducing and capping agent in the first step, while in the second step, silver nanoparticles were integrated in chitosan. The integration of AgNPs in the structure of chitosan was confirmed by ultraviolet‐visible, Fourier transform infrared spectroscopy, scanning electron microscopy techniques, and energy dispersive X‐ray. Surface plasmon resonance confirmed the formation of CS‐AgNPs with maximum absorbance at λmax between 405 ‐ 410 and 410 ‐ 430 nm for colloidal and films of CS‐AgNPs, respectively. The intensity of bands at 3408 cm?1 in the fourier transform infrared spectroscopy measurements was decreased substantially and shifted slightly to lower frequency (?υ = 43 cm?1). Scanning electron microscopy shows a spherical morphology of AgNPs with size of 62 nm for both colloidal and film samples, and energy dispersive X‐ray analysis shows peaks confirming AgNPs formation. 相似文献
27.
The ZnO filler has been introduced into a solid polymeric electrolyte of polyvinyl chloride (PVC)–ZnO–LiClO4, replacing costly organic filler for conductivity improvement. Ionic conductivity of PVC–ZnO–LiClO4 as a function of ZnO concentration and temperature has been studied. The electrolyte samples were prepared by solution casting
technique. The ionic conductivity was measured using impedance spectroscopy technique. It was observed that the conductivity
of the electrolyte varies with ZnO concentration and temperature. The temperature dependence on the conductivity of electrolyte
was modelled by Arrhenius and Vogel–Tammann–Fulcher equations, respectively. The temperature dependence on the conductivity
does not fit in both models. The highest room temperature conductivity of the electrolyte of 3.7 × 10−7 Scm−1 was obtained at 20% by weight of ZnO and that without ZnO filler was found to be 8.8 × 10−10 Scm−1. The conductivity has been improved by 420 times when the ZnO filler was introduced into the PVC–LiClO4 electrolyte system. It was also found that the glass transition temperature of the electrolyte PVC–ZnO–LiClO4 is about the same as PVC–LiClO4. The increase in conductivity of the electrolyte with the ZnO filler was explained in terms of its surface morphology. 相似文献
28.
L.A. Wahab M.B. El-Den A.A. Farrag S.A. Fayek K.H. Marzouk 《Journal of Physics and Chemistry of Solids》2009,70(3-4):604-608
Optical and electrical properties of Zn- and Cd-modified Cu2SnSe4 amorphous films have been studied. The results show that Zn and Cd incorporation decreases the thermal activation energy, the pre-exponential factor and the optical gap. Variation in the refractive index and extinction coefficient with the wavelength has been also reported. The relations between the optical gap and the chemical composition in the investigated films have been discussed in terms of the average heat of atomization. The effect of γ-radiation up to 71.25 Mrad dose on the optical gap was also studied. 相似文献
29.
Zehl T Wahab M Mögel HJ Schiller P 《Langmuir : the ACS journal of surfaces and colloids》2006,22(6):2523-2527
Monte Carlo simulations provide some insight into the self-assembly of amphiphiles in aqueous environment. A rather simple solvent-free model, with only two adjustable parameters in the effective pair potential, allows one to describe the formation of micelles, stable curved membranes, and metastable vesicles. Characteristic features of the self-assembled aggregates, such as the distribution of the micelle size and the value of the curvature elastic constant for membranes, can be obtained from simulated data. The capability of the simple approach was demonstrated for a surfactant model with three spherical segments. The extension of the simulation to molecules with more segments and branched amphiphiles is straightforward. 相似文献
30.