Pion electroproduction from nuclei near threshold

The electroproduction of low energy pions is calculated for experimental situations corresponding to the detection of only one of the outgoing particles. The final nuclear state is a superposition of particle-hole states, corresponding to the giant resonances. A comparison with the predictions of the Fermi gas model is made. The effect of final state interactions was included by using a distorted wave impulse approximation to describe electroproduction from nuclei. Distortion effects near threshold have a significant effect on the magnitude of the electroproduction cross section.     

镉取代对纳米镍铁氧体结构和磁性的影响

采用湿化学共沉淀法合成了Ni_1-xCd_xFe₂O₄ (0≤x≤0.5)的混合铁氧体,利用X射线衍射对其结构和晶相进行表征．结果表明：随着镉Cd浓度的增加晶格参数逐渐增大．扫描电子显微镜研究微观结构,TG/DTA研究了硫酸共沉淀物．揭示了在650 oC合成铁氧体同时进行分解．测量了纳米粒子的磁化强度和交流磁化率．结果表明,Ni_1-xCd_xFe₂O₄混合铁氧体的磁化率、居里温度和有效磁矩随着镉含量的增加下降。     

Major volatile constituents of Annona squamosa L. bark

The volatile constituents of Annona squamosa L. bark were identified from the essential oil obtained by steam distillation and studied by GC/MS. Six major components were identified as 1H-Cycloprop(e)azulene (3.46%), germacrene D (11.44%), bisabolene (4.48%), caryophyllene oxide (29.38%), bisabolene epoxide (3.64%) and kaur-16-ene (19.13%). The oil was also screened for its antimicrobial activity, which exhibited a significant antimicrobial activity against Bacillus subtilis and Staphylococcus aureus.     

Role of oxygen impurity in growth and magnetic properties of Ni83Fe17 permalloy thin films

To study the influence of oxygen impurities in the sputtering atmosphere on microstructure, and the magnetic and magnetotransport properties, thin films of Ni₈₃Fe₁₇ were deposited under dc magnetron sputtering technique into which regulated oxygen gas was introduced. The partial pressure of oxygen was varied from 2×10⁻⁷ to 3×10⁻⁶ mbar. X-ray diffraction patterns indicate the reduction of grain growth with increasing the oxygen partial pressure. The grain microstructure and the composition were confirmed through high resolution transmission electron microscopy attached with Scanning Transmission Electron Microscopy (STEM). Transition from canted to rectangular magnetic hysteresis loop was observed through magnetization measurements for samples prepared under higher oxygen partial pressure which implies the structural changes in the magnetic domain formation. These observations were further confirmed through the measurements of anisotropic magnetoresistance properties.     

Magnetic properties of rare earth ion (Sm) added nanocrystalline Mg-Cd ferrites, prepared by oxalate co-precipitation method

Nanocrystalline ferrite powder having the general formula Mg_1−xCd_xFe₂O₄+5% Sm³⁺ (x=0, 0.2, 0.4, 0.6, 0.8 and 1.0) was synthesized by chemical oxalate co-precipitation technique. The synthesized powder was characterized by X-ray, IR and SEM techniques. The XRD analysis confirms cubic spinel phase with orthoferrite secondary phase. The lattice constant increases with increase in Cd²⁺ content (x). It is smaller than that for pure Mg-Cd ferrites. The average crystallite size lies in the range 28.69-32.66 nm. Saturation magnetization and magnetic moment increase with cadmium content up to x=0.4 and decrease thereafter. This is attributed to the existence of localized canted spin. The decrease in saturation magnetization and magnetic moment beyond x=0.4 is due to the presence of triangular spin arrangement on B-site. Coercivity and remanent magnetization decrease while Y-K angles increase with Cd²⁺ content. The Sm³⁺ addition improves the magnetic properties.     

Fractional partial differential equations with boundary conditions

We identify the stochastic processes associated with one-sided fractional partial differential equations on a bounded domain with various boundary conditions. This is essential for modelling using spatial fractional derivatives. We show well-posedness of the associated Cauchy problems in $C_0(\mathrm{\Omega })$ and $L_1(\mathrm{\Omega })$. In order to do so we develop a new method of embedding finite state Markov processes into Feller processes on bounded domains and then show convergence of the respective Feller processes. This also gives a numerical approximation of the solution. The proof of well-posedness closes a gap in many numerical algorithm articles approximating solutions to fractional differential equations that use the Lax–Richtmyer Equivalence Theorem to prove convergence without checking well-posedness.     

Deposition of copper iodide thin films by chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR) methods

In this paper, we report structural, morphological, electrical studies of copper iodide (CuI) thin films deposited onto glass substrates by chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR) methods. CuI thin films were characterized for their structural, morphological and wettability studies by means of X-ray diffraction (XRD), FT-Raman spectroscopy, scanning electron microscopy (SEM), optical absorption, and contact angle measurement methods. Thickness of thin films was 1 ± 0.1 μm measured by gravimetric weight difference method. The CuI thin films were nanocrystalline, with average crystal size of ～60 nm. The FT-IR study confirmed the formation of CuI on the substrate surface. SEM images revealed the compact and cube like structure for CuI thin films deposited by CBD and SILAR methods, respectively. Optical absorption study revealed optical energy gaps as 2.3 and 3.0 eV for CBD and SILAR methods, respectively. Wettability study indicated that CuI thin films deposited by SILAR method are more hydrophobic as compared to CBD method.     

Lewis Acid Directed Regioselective Metalations of Pyridazine

Mono‐ or bidentate boron Lewis acids trigger a regioselective magnesiation or zincation of pyridazine in position C3 (ortho product) or C4 (meta product). The regioselectivity of the metalation was rationalized with the help of calculated pK_a values of both pyridazine and pyridazine/Lewis acid complexes.     

Cation disorder and structural studies on Bi4−x Nd x Ti3O12 (0.0≤x≤2.0)

Here we report the results of combined powder X-ray and neutron diffraction studies of Bi_4?x Nd _x Ti₃O₁₂ (0.0 ≤ x ≤ 2.0) compositions. The parent Bi₄Ti₃O₁₂ has an orthorhombic lattice (space group: B2cb) with unit cell parameters a = 5.4432(5) Å, b = 5.4099(5) Å and c = 32.821(2) Å, and V = 966.5(1) ų. This orthorhombic lattice is retained in all the studied compositions. The unit cell parameters gradually decrease with Nd³⁺ ion concentration with a discontinuity at x = 0.75. Orthorhombicity of the lattice decreases with increase in Nd³⁺ content in the lattice. The orthorhombic unit cell parameters for a representative Bi₂Nd₂Ti₃O₁₂ composition are: a = 5.3834(9), b = 5.3846(9) and c = 32.784(1) Å. The observed orthorhombic distortion at x = 2.0 is very small and thus the crystal structure apparently has a pseudo-tetragonal lattice. In addition, Nd³⁺ preferentially substitutes in the perovskite slab of the Aurivillius structure. The fraction of Nd³⁺ in the fluorite slab increases with increase in Nd³⁺ contents.