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101.
Sudhir Malik S. K. Soni R. K. Shivpuri 《Zeitschrift fur Physik C Particles and Fields》1995,67(2):239-244
Experimental results on multiplicity distributions for full phase space and in different pesudorapidity windows of charged secondary particles produced in proton-nucleon collisions at 800 GeV are presented and discussed. It is found that all these multiplicity distributions are well described by negative binomial distributions. We interpret our results on the basis of clan model. The bin size dependence of multiplicity distribution of charged secondary particles in proton-nucleon interactions is analysed in terms of multifractals. The values of generalised dimensions obtained from fitted distributions show a good agreement with those obtained from the data. 相似文献
102.
Efficient solid phase synthesis of oligoribonucleotide and its phosphorothioate analogue is described that utilizes the dimethoxytrityl (DMTr) for 5′-protection and t-butyldimethylsilyl (t-BDMS) group for 2′-protection of ribonucleoside monomers and the H-phosphonate coupling procedure. The synthetic cycles have been optimised to use only 8–10 fold excess of monomer at each coupling step, leading to an average coupling yield of 97%. 相似文献
103.
The photocatalytic degradation of 4-CP was mathematically modelled using the mechanistic insights and data presented in an earlier study [1]. The solution and surface concentrations of reacting species were calculated by solving a system of differential equations that account for oxidation reactions of dissolved and adsorbed species, adsorption and desorption, reduction of oxygen, and hole-electron recombination. The differential equations were integrated over discrete time-periods and annular regions of the photoreactor. The resulting model predicts the trends observed in studies in other laboratories using different experimental apparati. Using the model it is possible to predict effects of reactor geometry, TiO2 loading, light intensity, and mixing on the course of TiO2 photocatalytic oxidation. The model verifies the importance of surface reactions, and reveals the need to better understand the fate and role of oxygen in TiO2 photocatalytic systems. 相似文献
104.
INDEPENDENT EFFECTS OF PHYTOCHROME AND NITRATE ON NITRATE REDUCTASE AND NITRITE REDUCTASE ACTIVITIES IN MAIZE 总被引:1,自引:0,他引:1
Abstract— Involvement of phytochrome in the regulation of nitrate reductase (NR) and nitrite reductase (NIR) activities in excised, etiolated leaves of Zea mays (L.) variety 'Ganga-5' is demonstrated using low energy and high irradiance responses of phytochrome action. Photoreversibility by far-red light of red light stimulated increases in NR and NIR activities was lost by 2 h. Red light given to the leaves, when induction by NO- 3 , was saturated, further increased both enzyme activities. Even if red light was given 4–8 h before NO- 3 , it still increased both NR and NIR activities. 相似文献
105.
Paul S 《Applied biochemistry and biotechnology》1998,75(1):13-24
The light (L) chain of a model antibody (Ab) was deduced to contain a serine protease-like catalytic site capable of cleaving
peptide bonds. The catalytic site is encoded by a germline VL gene. The catalytic activity can potentially be improved by somatic sequence diversification and pairing of the L chain with
the appropriate heavy chain. Autoimmune disease is associated with increased synthesis of antigen (Ag)-specific Abs, but the
reasons for this phenomenon are not known. Only recently has attention turned to the functional role of the catalytic function.
Preliminary studies confirm that the catalytic cleavage of peptide bonds is a more potent means to achieve Ag neutralization,
compared to reversible Ag binding. Administration of a monoclonal Ab to VIP in experimental animals induces an inflammatory
response in the airways, suggesting that catalytic autoantibodies to this peptide found in airway disease and lupus are capable
of causing airway dysfunction. The phenomenon of autoantibody catalysis can potentially be applied to isolate efficient catalysts
directed against tumor or microbial Ags by exposing the autoimmune repertoire to such Ags or their analogs capable of recruiting
the germline VL gene encoding the catalytic site. 相似文献
106.
CO(2) as a separation switch for ionic liquid/organic mixtures 总被引:6,自引:0,他引:6
A novel technique to separate ionic liquids from organic compounds is introduced which uses carbon dioxide to induce the formation of an ionic liquid-rich phase and an organic-rich liquid phase in mixtures of methanol and 3-butyl-1-methyl-imidazolium hexafluorophosphate ([C4mim][PF6]). If the temperature is above the critical temperature of CO2 then the methanol-rich phase can become completely miscible with the CO2-rich phase, and this new phase is completely ionic liquid-free. Since CO2 is nonpolar, it is not equipped to solvate ions. As the CO2 dissolves in the methanol/[C4mim][PF6] mixture, the solvent power of the CO2-expanded liquid is significantly reduced, inducing the formation of the second liquid phase that is rich in ionic liquid. This presents a new way to recover products from ionic liquid mixtures and purify organic phases that have been contaminated with ionic liquid. Moreover, these results have important implications for reactions done in CO2/ionic liquid biphasic mixtures. 相似文献
107.
A detailed and systematic study is carried out of the \(B\bar B(N\bar N, N\bar \Delta , \Delta \bar \Delta )\) widths of the “True” (colour \(3 \times \bar 3\) ) diquoniums making use of the quark pair creation model supplemented by the idea of a quark-quark potential. The widths, which continue to be of the order of 10 MeV, help confirm our hypothesis of avoiding the need for the “Mock” (colour \(6 \times \bar 6\) ) diquoniums to explain the narrow width resonances observed in the production experiments. Another outcome concerns the criterion to select out the dominant ones among the numerous diquonium trajectories. It is proposed to replace the one based on “peripherality” withR~1/m π with another more natural one based on the width pattern itself. 相似文献
108.
The reversible charging and discharging effects associated with photoexcitation of a TiO2 shell in a Ag@TiO2 composite are described. The photoinduced charge separation in the TiO2 shell is followed by electron injection into the silver core. Interestingly, the charging of the silver core is associated with the shift in the surface plasmon band from 460 to 430 nm. The stored electrons are discharged upon exposure of the charged Ag@/TiO2 composite to an electron acceptor. As the electrons from the silver core are discharged, the original surface plasmon absorption of the Ag core is restored. 相似文献
109.
Charge separation and catalytic activity of Ag@TiO2 core-shell composite clusters under UV-irradiation 总被引:1,自引:0,他引:1
Photocatalytic properties of Ag@TiO2 composite clusters have been investigated using steady state and laser pulse excitations. Photoexcitation of TiO2 shell results in accumulation of the electrons in the Ag core as evidenced from the shift in the surface plasmon band from 460 to 420 nm. The stored electrons are discharged when an electron acceptor such as O2, thionine, or C60 is introduced into the system. Charge equilibration with redox couple such as C60/C60*- shows the ability of these core shell structures to carry out photocatalytic reduction reactions. The charge separation, charge storage, and interfacial charge-transfer steps that follow excitation of the TiO2 shell are discussed. 相似文献
110.
Densities and viscosities have been determined for binary mixtures of isopropyl acetate or isobutyl acetate with o-xylene, m-xylene, p-xylene and ethyl benzene at (303.15 and 313.15) K for the entire composition range. The excess molar volumes and deviations
in viscosity have been calculated from the experimental values. The variations of these parameters, with composition of the
mixtures and temperature, have been discussed in terms of molecular interactions occurring in these mixtures. Further, the
viscosities of these binary mixtures were calculated theoretically from their corresponding pure component data by using empirical
relations, and the results were compared with the experimental findings. 相似文献