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991.
H.U. Anderson M.M. Nasrallah B.K. Flandermeyer A.K. Agarwal 《Journal of solid state chemistry》1985,56(3):325-334
The stability of high-temperature fuel cell electrodes to their ambient environment is important for the long-term reliability of fuel cells. In this report the behavior of oxide electrode materials as a function of oxygen activity and temperature is considered. Models for the oxidation-reduction behavior of both p- and n-type oxides are presented. These models take into account the absorption and evolution of oxygen which take place as oxygen activity is varied. The resulting instability in electrical conductivity is explained as a consequence of changes in carrier concentration due to variability in ionic defect concentration. The proposed models are applied to acceptor-doped LaCrO3 and donor-doped SrTiO3. It is shown that the models explain the experimental data well and as a consequence diagrams can be made which show the regions of oxygen activity and temperature for which stability of electrical conductivity and defect structure might be expected. 相似文献
992.
We consider the boundary value problem
where r 2, n
i 1 for i = 1, ... ,r,
and 0 = t
1 < t
2 < ... < t
r = 1. Criteria are offered for the existence of double and triple positive (in some sense) solutions of the boundary value problem. Further investigation on the upper and lower bounds for the norms of these solutions is carried out for special cases. We also include several examples to illustrate the importance of the results obtained. 相似文献
993.
S. Banerjee S. N. Ganguli A. Gurtu P. K. Malhotra R. Raghavan A. Subramanian K. Sudhakar M. M. Agarwal T. K. Chatterjee J. M. Kohli J. P. Lamba I. S. Mittra J. B. Singh P. M. Sood Dev Anand P. V. K. S. Baba G. L. Kaul Y. Prakash N. K. Rao G. Singh R. Hamatsu T. Hirose S. Kitamura T. Yamagata Bombay Collaboration Chandigarh Collaboration Jammu Collaboration Tokyo Collaboration 《Zeitschrift fur Physik C Particles and Fields》1986,32(2):163-170
A study of \(\bar np\) annihilations with \(\bar n\) momentum between 0.5 and 0.8 GeV/c is presented. The search fors-channel resonances in \(\bar np\) annihilations reveal possibly two narrow structures in the odd pions final state. Inclusiveρ 0 andf 0 cross sections in \(\bar np\) annihilations have been estimated to be 9.0±0.6 mb and 3.4±0.6 mb respectively. Longitudinal and transverse momentum distributions for inclusiveρ 0 production have been presented. A study of resonance production in exclusive final state revealsρ 0 production to be dominant in the odd pion final states andρ +,ω 0 productions are most important for the even pion final states. Theπ + π ? effective mass spectra in the backward and the forward directions in the \(\bar np\) c.m. system have been examined for a possible ?-ω interference effect. 相似文献
994.
Umesh P. Agarwal Sally A. Ralph Richard S. Reiner Carlos Baez 《Cellulose (London, England)》2016,23(1):125-144
The structure of wood cell wall cellulose in its native state remains poorly understood, limiting the progress of research and development in numerous areas, including plant science, biofuels, and nanocellulose based materials. It is generally believed that cellulose in cell wall microfibrils has both crystalline and amorphous regions. However, there is evidence that appears to be contrary to this assumption. Here we show, using 1064-nm FT-Raman spectroscopy, that (1) compared to the crystalline state, cellulose in the never-dried native state is laterally aggregated but in a less-than crystalline state wherein internal chains are water-accessible, (2) hydroxymethyl groups (CH2OH) in cellulose exist not only in the tg conformation but also in the gt rotamer form, and (3) in native-state fibrils, low-frequency Raman bands due to cellulose crystal domains are absent, indicating the lack of crystallinity. Further evidence of the absence of crystallinity of the fibrils was the failure of the normal 64 % H2SO4 hydrolysis procedure to produce nanocellulose crystals from untreated wood. X-ray diffraction data obtained on wood, treated-wood, and wood-cellulose samples were consistent with the new finding and indicated that full-width-at-half-height of the X-ray diffractograms and lateral disorder in samples as measured by Raman were correlated (R2 = 0.95). 相似文献
995.
V. Sharma P. Srivastava D. D. Agarwal K. Diwedi 《Russian Journal of Organic Chemistry》2016,52(3):433-436
A new reagent system consisting of aqueous KI3 in AcOH and NaIO4 as oxidant has been found to be effective in iodinating a variety of commercially important aromatic substrates under ambient conditions. The presence of Na2SO3 enhances the yield and the product purity. The procedure ensures high yields (72–98%) at room temperature in a short reaction time. A remarkable feature of this system is that even acidsensitive functionalities like anilines can be iodinated quantitatively. 相似文献
996.
Quantitative Comparison of the Antimicrobial Efficiency of Leaching versus Nonleaching Polymer Materials 下载免费PDF全文
Joerg Bruenke Ingolf Roschke Seema Agarwal Thomas Riemann Andreas Greiner 《Macromolecular bioscience》2016,16(5):647-654
New antimicrobial materials will be more and more in the focus for hygienic and clinical disease control. Antimicrobial materials have to be distinguished in leaching and nonleaching materials. For many applications of antimicrobial materials on implants the use of nonleaching materials is essential. Therefore, the antimicrobial efficiency of leaching and nonleaching polymers has been investigated quantitatively in vitro in direct comparison on a highly relevant implant of central venous catheters (CVCs) using a well‐established called Certika test. This test is especially designed to test antimicrobial properties of leachable and nonleachable materials. This contribution demonstrates that newly developed nonleaching antimicrobial CVCs are equivalent to conventional leaching CVC systems in their antimicrobial performance against gram‐positive and gram‐negative bacteria, as well as Candida species. The use of new nonleaching antimicrobial polymers as shown here for CVCs represents a different mode of action with the aim to prevent infections also with antibiotic‐resistant strains and reduced side effects.
997.
Harshal Agarwal Vishnu R. Unni K.T. Akhil N.T. Ravi S. Md. Iqbal R.I. Sujith Bala Pesala 《Applied Acoustics》2016
In the past decade, a variety of thermoacoustic engines (TAEs) were devised to convert thermal energy to acoustic power. In this paper, we optimized the design of a standing wave thermoacoustic generator that can provide high intensity acoustic pressure and convert it into electrical power output using a low cost alternator. Three prototypes of standing wave thermoacoustic generator (TAG) were designed to optimize the overall efficiency. The first prototype of standing wave TAG could produce an acoustic pressure of 0.9 kPa (153 dB) with an input thermal power of 210 W. Further, the maximum heat to electrical conversion efficiency was 0.045% with an input thermal power of 250 W. However, the performance of this system was not fully optimized. The performance of TAE depends upon various parameters including stack position, stack length and resonator length. Hence, a new second prototype of tunable TAG was developed to tune these critical parameters in order to improve the overall efficiency. A compact third prototype of TAG was successfully built with optimized parameters and has been tested. In the improved design, high intensity acoustic pressure of 2.9 kPa (163.5 dB) was observed for the same 210 W input thermal power. The maximum heat to electrical energy conversion efficiency was 0.084% with an input of 250 W which is 87% higher as compared to the first prototype. The major reason for the lower conversion efficiency is due to the low efficiency of the alternator. In future, high efficiency alternator designs can be employed along with careful impedance matching to obtain higher conversion efficiencies. The results described in this paper demonstrate the potential of developing compact portable acoustic power and electricity generators for decentralized power applications. 相似文献
998.
Assembly of Gold Nanoparticles on Gold Nanorods Using Functionalized Poly(N‐isopropylacrylamide) as Polymeric “Glue” 下载免费PDF全文
Ziyin Fan Moritz Tebbe Andreas Fery Seema Agarwal Andreas Greiner 《Particle & Particle Systems Characterization》2016,33(9):698-702
A telechelic thermoresponsive polymer, α‐amino‐ω‐thiol‐poly(N‐isopropylacrylamide) (H2N‐PNiPAM‐SH), is used as the polymeric glue to assemble gold nanoparticles (AuNPs) around gold nanorods (AuNRs) into a satellite structure. Prepared by reversible addition‐fragmentation chain transfer polymerization followed by hydrazinolysis, H2N‐PNiPAM‐SH is able to interlink the two types of the gold building blocks with the thiol‐end grafting on AuNRs and the amine‐end coordinating on the AuNP surface. The density of the grafted AuNPs on AuNRs can be tuned by adjusting the molar ratio between AuNPs and AuNRs in the feed. The resulted satellite‐like assembly exhibits unique optical property that was responsive to temperature change. 相似文献
999.
1000.
Since the induced objects on a lightlike submanifold depend on its screen distribution which, in general, is not unique and hence we can not use the classical submanifold theory on a lightlike submanifold in the usual way. Therefore, in present paper, we study screen conformal lightlike submanifolds of a semi-Riemannian manifold, which are essential for the existence of unique screen distribution. We obtain a characterization theorem for the existence of screen conformal lightlike submanifolds of a semi-Riemannian manifold. We prove that if the differential operator Ds is a metric Otsuki connection on transversal lightlike bundle for a screen conformal lightlike submanifold then semi-Riemannian manifold is a semi-Euclidean space. We also obtain some characterization theorems for a screen conformal totally umbilical lightlike submanifold of a semi-Riemannian space form. Further, we obtain a necessary and sufficient condition for a screen conformal lightlike submanifold of constant curvature to be a semi-Euclidean space. Finally, we prove that for an irrotational screen conformal lightlike submanifold of a semi-Riemannian space form, the induced Ricci tensor is symmetric and the null sectional curvature vanishes. 相似文献