排序方式: 共有110条查询结果,搜索用时 15 毫秒
101.
Raveendran Sindhu Parameswaran Binod Karri Satyanagalakshmi Kanakambaran Usha Janu Kuttavan Valappil Sajna Noble Kurien Rajeev Kumar Sukumaran Ashok Pandey 《Applied biochemistry and biotechnology》2010,162(8):2313-2323
In recent years, growing attention has been focused on the use of lignocellulosic biomass as a feedstock for the production
of ethanol, a possible renewable alternative to fossil fuels. Several pretreatment processes have been developed for decreasing
the biomass recalcitrance, but only a few of them seem to be promising. In this study, effect of various organic solvents
and organic acids on the pretreatment of sugarcane bagasse was studied. Among the different organic acids and organic solvents
tested, formic acid was found to be effective. Optimization of process parameters for formic acid pretreatment was carried
out. The structural changes before and after pretreatment was investigated by scanning electron microscopy, X-ray diffraction
(XRD), and Fourier transform infrared (FTIR) analysis. The X-ray diffraction profile showed that the degree of crystallinity
was more for pretreated biomass than that of untreated. The FTIR spectra shown at the stretching of hydrogen bonds of pretreated
sugarcane bagasse arose at higher number. It also revealed that the cellulose content in the solid residue increased because
the hemicelluloses fraction in raw materials was released by acid hydrolytic reaction. 相似文献
102.
Sandhya C Binod P Nampoothiri KM Szakacs G Pandey A 《Applied biochemistry and biotechnology》2005,127(1):1-15
Antifungal activity of chitinase can be effectively utilized in biologic pest control strategies. Because solid-state cultivation
has been termed a cost-effective means for fungal growth and metabolite production, chitinase production by Trichoderma harzianum was studied using wheat bran-based solid medium containing 1% colloidal chitin. Chitinase synthesis was found to be growth
associated because maximum enzyme (5.4 U/g of dry substrate) and biomass production occurred at 72h. Substrate moisture had
a critical impact on chitinase production; five grams of medium having an initial moisture content of 68.4% when incubated
for 72 h increased the enzyme yield to 9.3 U/g of dry substrate. Optimization of colloidal chitin concentration showed that
improvements in chitinase yield and maximum activity were attained with a 2% (w/w) concentration. Supplementation of additional
nitrogen sources also influenced enzyme production, and the best yield was obtained with yeast extract. The effect of crude
chitinase on hyphal morphology of the phytopathogenic fungus Collelotrichum gloeosporioides was swelling as well as lysis of hyphal wall, depending on the age of the mycelium. Studies of pH and thermal stability showed
that crude culture filtrate was active over pH 4.0–6.0 and retained about 48.2% activity after 40 min of incubation at 40°C. 相似文献
103.
Virgil Percec Makoto Obata Jonathan G. Rudick Binod B. De Martin Glodde Tushar K. Bera Sergei N. Magonov V. S. K. Balagurusamy Paul A. Heiney 《Journal of polymer science. Part A, Polymer chemistry》2002,40(20):3509-3533
The synthesis of 2‐ethynyl‐9‐substituted carbazole and 3‐ethynyl‐9‐substituted carbazole monomers containing first‐generation chiral and achiral dendritic (i.e., minidendritic) substituents, 2‐ethynyl‐9‐[3,4,5‐tris(dodecan‐1‐yloxy)benzyl]carbazole (2ECz), 3‐ethynyl‐9‐[3,4,5‐tris(dodecan‐1‐yloxy)benzyl]carbazole (3ECz), 2‐ethynyl‐9‐{3,4,5‐tris[(S)‐2‐methylbutan‐1‐yloxy]benzyl}carbazole (2ECz*), and 3‐ethynyl‐9‐{3,4,5‐tris[(S)‐2‐methylbutan‐1‐yloxy]benzyl}carbazole (3ECz*), is presented. All monomers were polymerized and copolymerized by stereospecific polymerization to produce cis‐transoidal soluble stereoisomers. A structural analysis of poly(2ECz), poly(2ECz*), poly(3ECz), poly(3ECz*), poly(2ECz*‐co‐2ECz), and poly(3ECz*‐co‐3ECz) by a combination of techniques, including 1H NMR, ultraviolet–visible, and circular dichroism spectroscopy, thermal optical polarized microscopy, and X‐ray diffraction experiments, demonstrated that these polymers had a helical conformation that produced cylindrical macromolecules exhibiting chiral and achiral nematic phases. Individual chains of these cylindrical macromolecules were visualized by atomic force microscopy. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3509–3533, 2002 相似文献
104.
In this article we study some properties of the Nörlund and Riesz mean of sequences of fuzzy real numbers. We establish necessary and sufficient conditions for the Nörlund and Riesz means to transform convergent sequences of fuzzy numbers into convergent sequences of fuzzy numbers with limit preserving. 相似文献
105.
On a Class of Generalized Lacunary Difference Sequence Spaces Defined by Orlicz Functions 总被引:1,自引:0,他引:1
In this article we introduce the generalized lacunary difference sequence spaces [N_θ,M,Δ~m]_0,[N_θ,M,Δ~m]_1 and [N_θ,M,Δ~m]_∞using m~(th)- difference.We study their properties like completeness,solidness,symmetricity.Also we obtain some inclusion relations involving the spaces [N_θ,M,Δ~m]_0,[N_θ,M,Δ~m]_1 and[N_θ,M,Δ~m]_∞and the Cesàro summable and strongly Cesàro summable sequences. 相似文献
106.
This paper evaluates the performance of an underlay cognitive relay network under imperfect channel state information (CSI) where a secondary user (SU) transmits using a secondary relay (SR) based on decode and forward scheme. The outage probability (OP) of SU is investigated in a scenario where the decode and forward relay harvests energy from radio frequency signal of SU. The relay uses a fraction of time for harvesting in time switching–based relaying (TSR) while a fraction of received power is used for harvesting in power splitting–based relaying (PSR) scheme. The SU and relay control their transmit power using a scaling factor, based on CSI of the interfering links (ie, links from SU transmitter and SR to the primary user [PU] receiver) to protect the quality of service of PU. The available CSI at the SU and SR are imperfect due to practical limitation. Analytical expressions of the OP are derived for TSR‐ and PSR‐based schemes. The impact of harvesting time, power splitting ratio, imperfect CSI, PU outage constraint and interference threshold on the OP of the SU network, and average transmit power of SR is indicated. Further, the impact of multiple SRs is also shown. 相似文献
107.
Band notched UWB circular monopole antenna with inductance enhanced modified mushroom EBG structures
Naveen Jaglan Samir Dev Gupta Binod Kumar Kanaujia Shweta Srivastava 《Wireless Networks》2018,24(2):383-393
Circular monopole antenna for ultra-wide band applications with notch band transition from WLAN to WiMAX is presented. The proposed antenna rejects WiMAX band (3.3–3.8 GHz). Antennas utilises modified mushroom-type electromagnetic band gap (EBG) structures to achieve band-notched designs. The proposed inductance enhanced modified EBG structures are 34 % compact than the conventional mushroom EBG structures. The band notched antenna designs using EBG structures have advantages like notch-frequency tuning, antenna design independent approach and omnidirectional radiation pattern. The step wise effect of inductance enhancement and tuning of notch from WLAN band (5–6 GHz) to WiMAX band is shown. Effect of variation of EBG structure parameters on which notched frequency depends is investigated. The proposed antenna has been fabricated on low cost FR4 substrate with overall dimensions as (42 × 50 × 1.6) mm3. Measured results are in good agreement with simulated ones. 相似文献
108.
Binod Vaidya Dimitrios Makrakis Jong Hyuk Park Sang-Soo Yeo 《Wireless Personal Communications》2011,56(3):385-401
A wireless multihop network is emerging as one of the most important technologies in the field of ubiquitous networking. However,
a number of formidable challenges remain, several of the most crucial been associated with robustness and network security.
In this paper, we introduce a comprehensive resilient security framework for wireless ad hoc networks that are using multipath
routing. It deploys an integrated multisignatures scheme and uses a self-certified public keying technique to ensure secure
route discovery. In addition, it uses the Schnorr signature scheme along with an information dispersal algorithm to ensure
secure data transfer. We provide security analysis of the proposed approach and compare it with several existing popular schemes.
It can be seen that the proposed approach is more secure than other existing schemes. We also evaluated the proposed approach
by means of computer simulation and compared its performance to that of the existing popular schemes. The results are in favor
of the proposed technique in terms of efficiency and effectiveness. 相似文献
109.
In recent past, Hawking temperature has been modified for the validity of thermodynamical laws at the event horizon in general relativity context. This lead to the introduction of modified Hawking temperature and it has been found that the modified Hawking temperature is more realistic on the event horizon. With this motivation, here we investigate the thermodynamical consistency of scalar-tensor gravity based models by examining the validity of the generalized second law of thermodynamics (GSLT) and thermodynamical equilibrium (TE) at the event horizon. In order to attain our goal, we consider a spatially flat Friedman–Robertson–Walker Universe filled with ordinary matter and the boundary of the Universe bounded by the event horizon that is in thermal equilibrium with modified Hawking temperature. Next, we calculate the general expressions for the GSLT and TE using modified Hawking temperature in the context of the more general action of scalar-tensor gravity where there is a non-minimally coupling between the scalar field and matter Lagrangian (as the chameleon field). From the general expression of GSLT, we find that the null energy condition must hold for a viable scalar-tensor model of the Universe dominated by a perfect fluid. Furthermore, in order to better understand these complicated general expressions of GSLT and TE, we explore the validity of the GSLT and TE for two viable models of scalar-tensor gravity namely Brans–Dicke gravity with a self-interacting potential and Chameleon gravity at the event horizon using special cosmological solutions. Finally, some graphical representation of the GSLT and TE have been presented. From the graphical analysis, we found that the power-law forms of the scale factor and scalar field is much favourable for the study of universal thermodynamics as compared to other choices of the scalar field and the analytic function. 相似文献
110.
Binod Raj Giri Krishna Prasad Shrestha Tam V.-T. Mai Fabian Mauss Lam K. Huynh 《国际化学动力学杂志》2023,55(1):3-14
Amino (NH2) radicals play a central role in the pyrolysis and oxidation of ammonia. Several reports in the literature highlight the importance of the reactions of NH2 radicals with fuel in NH3-dual-fuel combustion. Therefore, we investigated the reactions of NH2 radicals with methanol (CH3OH) and ethanol (C2H5OH) theoretically. We explored the various reaction pathways by exploiting CCSD(T)/cc-pV(T, Q)Z//M06-2X/aug-cc-pVTZ level of theory. The reaction proceeds via complex formation at the entrance and exit channels in an overall exothermic process. We used canonical transition state theory to obtain the high-pressure limiting rate coefficients for various channels over the temperature range of 300–2000 K. We discerned the role of various channels in the potential energy surface (PES) of NH2 + CH3OH/C2H5OH reactions. For both reactions, the hydrogen abstraction pathway at the OH-site of alcohols plays a minor role in the entire T-range investigated. By including the title reactions into an extensive kinetic model, we demonstrated that the reaction of NH2 radicals with alcohols plays a paramount role in accurately predicting the low-temperature oxidation kinetics of NH3-alcohols dual fuel systems (e.g., shortening the ignition delay time). On the contrary, these reactions have negligible importance for high-temperature oxidation kinetics of NH3-alcohol blends (e.g., not affecting the laminar flame speed). In addition, we calculated the rate coefficients for NH2 + CH4 = CH3 + NH3 reaction that are in excellent agreement with the experimental data. 相似文献