Superconducting properties of very high quality NbN thin films grown by high temperature chemical vapor deposition

Niobium nitride (NbN) is widely used in high-frequency superconducting electronics circuits because it has one of the highest superconducting transition temperatures ($T_c$ $\sim$ 16.5 K) and largest gap among conventional superconductors. In its thin-film form, the $T_c$ of NbN is very sensitive to growth conditions and it still remains a challenge to grow NbN thin film (below 50 nm) with high $T_c$. Here, we report on the superconducting properties of NbN thin films grown by high-temperature chemical vapor deposition (HTCVD). Transport measurements reveal significantly lower disorder than previously reported, characterized by a Ioffe-Regel ($k_F$$\ell$) parameter of $\sim$ 14. Accordingly we observe $T_c$ $\sim$ 17.06 K (point of 50% of normal state resistance), the highest value reported so far for films of thickness below 50 nm, indicating that HTCVD could be particularly useful for growing high quality NbN thin films

Accounting for the effect of heterogeneous plastic deformation on the formability of aluminium and steel sheets

Forming Limit Curves characterise ‘mean’ failure strains of sheet metals. Safety levels from the curves define the deterministic upper limit of the processing and part design window, which can be small for high strength, low formability materials. Effects of heterogeneity of plastic deformation, widely accepted to occur on the microscale, are neglected. Marciniak tests were carried out on aluminium alloys (AA6111-T4, NG5754-O), dual-phase steel (DP600) and mild steel (MS3). Digital image correlation was used to measure the effect of heterogeneity on failure. Heterogeneity, based on strain variance was modelled with the 2-component Gaussian Mixture Model and a framework was proposed to 1) identify the onset of necking and to 2) re-define formability as a probability to failure. The result were ‘forming maps’ in major-minor strain space of contours of constant probability (from probability, P=0 to P=1), which showed how failure risk increased with major strain. The contour bands indicated the unique degree of heterogeneity in each material. NG5754-O had the greatest width (0.07 strain) in plane strain and MS3 the lowest (0.03 strain). This novel characterisation will allow engineers to balance a desired forming window for a component design with the risk to failure of the material

Soil Chemical Characteristics of Organic and Conventional Agriculture

Use of chemical fertilizers and pesticides on intensive land of both lowland and upland food crops have been shown to increase agricultural productivity significantly. Research aimed to study soil chemical characteristics and soil pesticide residues at some crops of organic and conventional farms. The research was carried out in  Laboratory of Soil Chemistry, Indonesian Soil Research Institute and in Laboratory of Agrochemical Residue, Indonesian Agricultural Environment Research Institute, Bogor from February to July 2015. Soil samples at 0-10 cm depth were taken compositely from broccoli (Brassica oleracea), carrots (Daucus carota), maize (Zea mays), and tomatoes (Solanum lycopersicum) farms in Bogor Regency as well as from rice field in Tasikmalaya Regency at both organic and conventional farms. Soil chemical characteristics were analyzed include: soil organic-C (Walkey and Black), total-N (Kjeldahl), potential-P (HCl 25%), available-P (Olsen), potential-K (HCl 25%), available-K (NH4OAc 1 N pH 7), CEC (NH4OAc 1 N pH 7), and pH (soil : water = 1: 5), while pesticide residues included levels of organochlorine (lindane, aldrin, heptaklor, dieldrin, DDT, endosulfan); organophosphates (diazinon, fenitrotin, metidation, paration, profenofos); and carbamates (carbofuran, MIPC, BPMC) in the soil by using Gas Chromatography method. Results showed that levels of soil organic-C, total-N, potential and available-P, potential and available-K, CEC, pH  at organic farms were higher than those at conventional farms. Some pesticide residues compound (organochlorines, organophosphates, and carbamates) were detected at conventional farm, while those at organic farm were not detected (trace).Keywords: Conventional farm, organic farm, pesticide residues, soil properties. [How to Cite: Muhammad AA, F Hazra, S Salma and D Nursyamsi. 2016. Soil Chemical Characteristics of Organic and Conventional Agriculture. J Trop Soils 21: 19-25. Doi: 10.5400/jts.2016.21.1.19][Permalink/DOI: www.dx.doi.org/10.5400/jts.2016.21.1.19]&nbsp

Synthesis of unnatural hydroxyanthraquinones: Experiments towards total synthesis of pradimicinone

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Potentilla fulgens Wall

ABSTRACT The paper highlights some of the most important Ayurvedic medicinal plants of North Eastern India having anticancer potential. A brief review of distribution and pharmacological study (both in vivo and in vitro) of ten Ayurvedic medicinal plants of the region published by various researchers is illustrated in this paper. The medicinal plants discussed here are Enhydra Fluctuans Lour (Sanskrit: Hilamochika), Ageratum conizoides Linn

Crystallographic dependence of the spin Hall angle in epitaxial Pt films: Comparison of optical and electrical detection of spin-torque ferromagnetic resonance techniques

The spin Hall effect appears in nature in two forms. Its intrinsic form is highly dependent on the crystal symmetry while its extrinsic form stems from impurity scattering. Its efficiency is defined by the spin Hall angle, θSH, and has profound impact on spintronic technologies. However, an accurate measurement of θSH is not straightforward nor the identification of its origin. In this work, we apply a spin-torque driven ferromagnetic resonance method that is probed in two different ways, optically and electrically, to study the dependence of θSH in the crystallographic direction in epitaxial Al2O3/Pt (111), MgO(110)/Pt (110), and MgO(001)/Pt (001) films. We show that the electrical technique is limited in its ability to accurately quantify θSH at high current densities, and in some cases, it may even result in erroneous θSH values. Such cases include films that exhibit a large inhomogeneous broadening. We find that θSH is strongly affected by the crystallographic direction. Our study extends the understanding of one of the most commonly used methods for the exploration of the spin Hall effect