3,419 research outputs found
Jordan-Schwinger realizations of three-dimensional polynomial algebras
A three-dimensional polynomial algebra of order is defined by the
commutation relations ,
where is an -th order polynomial in
with the coefficients being constants or central elements of the algebra.
It is shown that two given mutually commuting polynomial algebras of orders
and can be combined to give two distinct -th order polynomial
algebras. This procedure follows from a generalization of the well known
Jordan-Schwinger method of construction of and algebras from
two mutually commuting boson algebras.Comment: 10 pages, LaTeX2
Large nonlinear absorption and refraction coefficients of carbon nanotubes estimated from femtosecond Z-scan measurements
Nonlinear transmission of 80 and 140 femtosecond pulsed light with wavelength through single walled carbon nanotubes suspended in water
containing sodium dodecyl sulphate is studied. Pulse-width independent
saturation absorption and negative cubic nonlinearity are observed,
respectively, in open and closed aperture Z-scan experiments. The theoretical
expressions derived to analyze the z-dependent transmission in the saturable
limit require two photon absorption coefficient and a
nonlinear index to fit the data.Comment: 10 pages, 2 figures. Accepted and to appear in Applied Physics
Letter
μ-Opioid Receptor Up-Regulation and Functional Supersensitivity Are Independent of Antagonist Efficacy
Kinetics of hydrodeoxygenation of octanol over supported nickel catalysts: a mechanistic study
The hydrodeoxygenation (HDO) of 1-octanol as a model aliphatic alcohol of bio-oil was investigated in a continuous down-flow fixed-bed reactor over γ-Al2O3, SiO2, and HZSM-5 supported nickel catalysts in the temperature range of 488–533 K. The supported nickel catalysts were prepared by incipient wetness impregnation method and characterized by BET, XRD, TPR, TPD, H2 pulse chemisorption, and UV-vis spectroscopy. Characterization of supported nickel (or nickel oxide) catalysts revealed existence of dispersed as well as bulk nickel (or nickel oxide) depending on the extent of nickel loading and the nature of the support. The acidity of γ-Al2O3 supported nickel catalysts decreased with increasing the nickel loading on γ-Al2O3. n-Heptane, n-octane, di-n-octyl ether, 1-octanal, isomers of heptene and octene, tetradecane, and hexadecane were identified as products of HDO of 1-octanol. The C7 hydrocarbons were observed as primary products for catalysts with active metal sites such as γ-Al2O3 and SiO2 supported nickel catalysts. However, C8 hydrocarbons were primarily formed over acidic catalysts such as pure HZSM-5 and HZSM-5 supported nickel catalyst. The 1-octanol conversion increased with increasing nickel loading on γ-Al2O3, and temperature and decreasing pressure and WHSV. The selectivity to products was strongly influenced by temperature, nickel loading on γ-Al2O3, pressure, and types of carrier gases (nitrogen and hydrogen). The selectivity to C7 hydrocarbons was favoured over catalysts with increased nickel loading on γ-Al2O3 at elevated temperature and lower pressure. A comprehensive reaction mechanism of HDO of 1-octanol was delineated based on product distribution under various process conditions over different catalysts
INTELLIGENT TELEMETRY DRIVEN NETWORK
By streaming real-time Optical Transport Network (OTN) and optical performance parameters from network devices using telemetry, the values of the next few intervals may be forecasted. Proactive alerts may be provided to the users and corrective action may be taken if the user chooses. Possible impact to millions of users riding the system may thereby be avoided. This provides a seamless experience to the users
LOSS ALLOCATION OF TRANSMISSION LINE AND MINIMIZATION OF LOSS FOR 5 BUS,14 BUS &30 BUS SYSTEMS
The paper focuses on the issue of transmission loss allocation and transmission loss minimization by incorporating UPFC injection model using load flow analysis. To investigate the effect of the UPFC on the steady state condition of the system and load flow, different models can be used. These models are usually based on modification of traditional load flow methods. In this project, a mathematical model for UPFC referred as UPFC injection model is used. Since accurate power tracing is very difficult, allocation of losses for a particular transaction (in power business it is buying and selling system) may not be effectively realized. However loss allocation is an important aspect in determining the cost of transmission. Thus a methodology to find the losses accurately is vital. It is imperative to make sure that all users of the transmission network are charged proportionate to their usage and this aspect is all the more important because of the common infrastructure they use. The Z-bus loss allocation method is used to achieve the required objective. This method will promote more efficient network operations when implemented in deregulated electric industries. The Unified Power Flow Controller (UPFC) injection model is incorporated in Load Flow Model by the method of Newton Raphson Algorithm to study its effects for power flow control and losses minimization in the power system. In this project optimal placement of UPFC is conducted based on active power loss Sensitivity factors. Based on these sensitivity factors the UPFC is optimally placed in the required transmission line to investigate the impact of UPFC in the system. The changes in the system are studied to see the impact of the UPFC. The impact of UPFC are analyzed by using 5-Bus, IEE
Femtosecond carrier dynamics and saturable absorption in graphene suspensions
Nonlinear optical properties and carrier relaxation dynamics in graphene,
suspended in three different solvents, are investigated using femtosecond (80
fs pulses) Z-scan and degenerate pumpprobe spectroscopy at 790 nm. The results
demonstrate saturable absorption property of graphene with a nonlinear
absorption coefficient, , of ~2 to 9x10^-8 cm/W. Two distinct time scales
associated with the relaxation of photoexcited carriers, a fast one in the
range of 130-330 fs (related to carrier-carrier scattering) followed by a
slower one in 3.5-4.9 ps range (associated with carrier-phonon scattering) are
observed.Comment: 3 pages, 2 figures, 2 table
- …