A novel method of synthesis of dense arrays of aligned single crystalline copper nanotubes using electrodeposition in the presence of a rotating electric field

Copper nanotube arrays are synthesized by electrodeposition of copper into the porous alumina membranes in presence of a lateral rotating electric field. A computer simulation of the experiment gives the insight of growth mechanism. In principle, this method can be applied to synthesize nanotube arrays of all such materials which can be electrodeposited

Temperature dependent electrical resistivity of a single strand of ferromagnetic single crystalline nanowire

We have measured the electrical resistivity of a single strand of a ferromagnetic Ni nanowire of diameter 55 nm using a 4-probe method in the temperature range 3 K-300 K. The wire used is chemically pure and is a high quality oriented single crystalline sample in which the temperature independent residual resistivity is determined predominantly by surface scattering. Precise evaluation of the temperature dependent resistivity ($\rho$) allowed us to identify quantitatively the electron-phonon contribution (characterized by a Debye temperature $\theta_R$) as well as the spin-wave contribution which is significantly suppressed upon size reduction

Macro and microscopic characters of Maerua oblongifolia (Forssk.) A. Rich leaf

The paper deals with a detailed investigation on the leaves of Maerua oblongifolia (Forssk.) A. Rich. which includes it’s morphological, anatomical and powder analysis. It is a low woody bushy under-shrub belonging to the family Capparaceae. The leaves are used in treatment of as fever, ear ache, stomach ache, skin infections, urinary calculii, diabetes mellitus, epilepsy, rigidity in lower limbs, and abdominal colic. The leaf amphistomatic, with mostly anamocytic, few tetracytic stomata. In transverse section of leaf is ribbed on either sides at midvein, epidermis one layered. Mesophyll differentiated into palisade and spongy tissues. Ground tissue of midvein differentiated into palisade, collenchyma and parenchyma. The midvien consists of one large oval shaped vascular bundles arranged are at the centre. Petiole in transverse section is circular adaxially small, grooved at centre and epidermis is having one layered, a single circular vascular bundle present at the centre, vascular bundle is enclosed by endodermis. The powder microscopic and organoleptic characters are also presented in this study. This study would helps as an appropriate source for authentification of the present studied drug. &nbsp

Binary Cu(II) Complexes with 7-Hydroxy-8-phenylazonaphthalene-1,3-disulphonate (Orange G) & Mixed Ligand Complexes Involving 2,2-Dipyridyl & Nitrilotriacetic Acid as Primary Ligands

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A new method to derive middle atmospheric temperature profiles using a combination of Rayleigh lidar and O₂ airglow temperatures measurements

The vertical temperature profiles in a typical Rayleigh lidar system depends on the backscatter photon counts and the CIRA-86 model inputs. For the first time, we show that, by making simultaneous measurements of Rayleigh lidar and upper mesospheric O2 temperatures, the lidar capability can be enhanced to obtain mesospheric temperature profile up to about 95 km altitudes. The obtained results are compared with instantaneous space-borne SABER measurements for a validation

Electrical transport properties of nanostructured ferromagnetic perovskite oxides La_0.67Ca_0.33MnO_3 and La_0.5Sr_0.5CoO_3 at low temperatures (5 K > T >0.3 K) and high magnetic field

We report a comprehensive study of the electrical and magneto-transport properties of nanocrystals of La_0.67Ca_0.33MnO_3 (LCMO) (with size down to 15 nm) and La_0.5Sr_0.5CoO_3 (LSCO) (with size down to 35 nm) in the temperature range 0.3 K to 5 K and magnetic fields upto 14 T. The transport, magnetotransport and non-linear conduction (I-V curves) were analysed using the concept of Spin Polarized Tunnelling in the presence of Coulomb blockade. The activation energy of transport, \Delta, was used to estimate the tunnelling distances and the inverse decay length of the tunnelling wave function (\chi) and the height of the tunnelling barrier (\Phi_B). The magnetotransport data were used to find out the magnetic field dependences of these tunnelling parameters. The data taken over a large magnetic field range allowed us to separate out the MR contributions at low temperatures arising from tunnelling into two distinct contributions. In LCMO, at low magnetic field, the transport and the MR are dominated by the spin polarization, while at higher magnetic field the MR arises from the lowering of the tunnel barrier by the magnetic field leading to an MR that does not saturate even at 14 T. In contrast, in LSCO, which does not have substantial spin polarization, the first contribution at low field is absent, while the second contribution related to the barrier height persists. The idea of inter-grain tunnelling has been validated by direct measurements of the non-linear I-V data in this temperature range and the I-V data was found to be strongly dependent on magnetic field. We made the important observation that a gap like feature (with magnitude ~ E_C, the Coulomb charging energy) shows up in the conductance g(V) at low bias for the systems with smallest nanocrystal size at lowest temperatures (T < 0.7 K). The gap closes as the magnetic field and the temperature are increased.Comment: 13 figure

Modification in electrical transport with a change in geometry from a nanowire to a nanotube of copper: effect of the extra surface:

We have studied the temperature-dependent (3-300 K) electrical resistance of metal nanowires and nanotubes of the same diameter with the specific aim to understand the changes in electrical transport brought about by a change in the geometry of a nanowire to a nanotube. Single crystalline nanowires and nanotubes of copper were synthesized by electrodeposition in nanoporous alumina templates. The temperature-dependent resistivity data have been analysed using the Bloch-Gruneisen function for the lattice contribution to resistivity, and the characteristic Debye temperature theta(R) was determined along with the residual resistivity rho(0). Substantial size effects were observed in both the parameters rho(0) and theta(R), where the former is enhanced and the latter is suppressed from bulk to nanowires and further to nanotubes. It has been observed that the transport parameters in the nanotubes with wall thickness t are similar to those of a nanowire with diameter d, where d approximate to 2t in the specific size range used in this work. It is suggested that appreciable size effects in the electrical transport parameters occur due to the extra surface in the nanotube. In both nanotubes and nanowires, the single parameter that determines the size effect is the surface area to volume ratio

Esters of petroselinic acid containing Trachyspermum copticum seed oil: Potential industrial lubricant base stocks

126-134Trachyspermum copticum seed oil contains volatile oil rich in thymol, which is distilled out and used for medicinal and aromatic formulations. The seed powder after removal of the volatiles loses its importance. However, the fixed oil being rich in unsaturation with petroselinic acid (18:1, Δ6; 68.3%) and linoleic acid (18:2; 25.3%) is used for preparing biolubricant base stocks. Methyl, isopropyl and 2-ethyl hexyl esters of the oil have been converted to epoxides, followed by in situ hydroxylation and acylation using hexanoic and butyric anhydrides. The acylated products have been evaluated for lubricant properties, and are found to exhibit density (0.91-0.97 g/cc); viscosity of 23.5-27.3 cSt at 40°C and 4.85-5.33 cSt at 100°C. The values are comparable to jatropha acylated products. The products exhibited good copper corrosion resistance value of ‘1a’ and high flash points of 230-242°C. The acylated esters with good weld load behavior, and lower wear and pour point values and viscosity indices, 128.84-138.94, can be potential base stocks belonging to group III category lubricants with ISO VG Grade about 22. These products can be further explored for the preparation of hydraulic, metal working and other industrial fluid formulations