Banaras Hindu University

About: Banaras Hindu University is a education organization based out in Varanasi, Uttar Pradesh, India. It is known for research contribution in the topics: Population & Dielectric. The organization has 11858 authors who have published 23917 publications receiving 464677 citations. The organization is also known as: Kashi Hindu Vishvavidyalay & Benares Hindu University.

Preparation and structure refinement of Eu3+ doped CaMoO4 nanoparticles

Abstract: The nanoparticles of CaMoO4 : Eu3+ (Eu3+ = 0, 1, 3, 5, 7, 10 at. %) are prepared at low temperature (150 °C for 3 h) using urea hydrolysis in ethylene glycol. These are characterized by X-ray diffraction (XRD), infrared spectroscopy (IR) and transmission electron microscopy (TEM). From XRD study, it was found that the solubility limit of Eu3+ ions at the Ca2+ sites is up to 3 at. % and above this, phase segregation occurs. In combination with Rietveld analysis, its crystal structure was found to be tetragonal phase (space groupI41/a (88) and Z = 4 (number of CaMoO4 formula units per unit cell). Unit cell parameters and bond distances are calculated. The average crystallite sizes of as-prepared, 500 and 900 °C heated samples are found to be 20, 35 and 70 nm, respectively. The lattice strain is found to be 0.003–0.005. From IR study, the bands at 820 and 441 cm−1 are assigned to asymmetric stretching and bending vibrations of the MoO42− tetrahedron, respectively. From TEM study, the shape of particle was found to be spherical. The high resolution TEM suggests a change in orientation of the crystal on annealing up to 900 °C.

The role of abscisic acid in plant tissue culture: a review of recent progress

Abstract: Abscisic acid (ABA) plays a significant role in the regulation of many physiological processes of plants. It is often used in tissue culture systems to promote somatic embryogenesis and enhance somatic embryo quality by increasing desiccation tolerance and preventing precocious germination. ABA is also employed to induce somatic embryos to enter a quiescent state in plant tissue culture systems and during synthetic seed research. Application of exogenous ABA improves in vitro conservation and the adaptive response of plant cell and tissues to various environmental stresses. ABA can act as anti-transpirant during the acclimatization of tissue culture-raised plantlets and reduces relative water loss of leaves during the ex vitro transfer of plantlets even when non-functional stomata are present. This review focuses on the possible roles of ABA in plant tissue culture and recent developments in this area.

Multifunctional Er3+–Yb3+ codoped Gd2O3 nanocrystalline phosphor synthesized through optimized combustion route

Abstract: This paper reports the synthesis of high upconversion luminescent Gd2O3: Er3+, Yb3+ nanophosphor through optimized combustion route using urea as a reducing agent. The paper also reports the first observation of upconversion emission bands extending upto the UV region (335, 366 and 380 nm) in Er3+–Yb3+ co-doped phosphor materials. The fuel to oxidizer ratio has been varied to obtain the maximum upconversion luminescence. Three high intensity bands are found at 408, 523–548 and 667 nm due to the 4G11/2 → 4I15/2, 2H11/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions, respectively, along with the other bands. Input excitation power dependence has been studied for different transitions, and the saturation effect and decrease in the slope of different transitions at higher input pump power has been explained. Heat treatments of the samples show change in crystallite phase/size and relative upconversion luminescence intensities of blue, green and red bands. The color of the phosphor emission has shown to be tunable with change in the crystal structure as well as on excitation laser power and Er3+–Yb3+ concentration. The property of color tunability of the phosphor material has been used to record the fingerprint in different colors. Also, the future prospect of the nanocrystalline phosphor material as a sensor for temperature, using FIR method, has been explored.

Limits on Light Weakly Interacting Massive Particles from the First 102.8 kg×day Data of the CDEX-10 Experiment.

Abstract: We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of 8×10^{-42} and 3×10^{-36} cm^{2} at a 90% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass (m_{χ}) of 5 GeV/c^{2} are achieved. The lower reach of m_{χ} is extended to 2 GeV/c^{2}.