A Phenomenological Thermodynamic Energy Density Function For Ferroelectric Wurtzite Al1−xScxN Single Crystals

A Landau-Devonshire thermodynamic energy density function for ferroelectric wurtzite aluminum scandium nitride (Al1−xScxN) solid solution is developed. It is parametrized using available experimental and theoretical data, enabling the accurate reproduction of composition-dependent ferroelectric properties, such as spontaneous polarization, dielectric permittivity, and piezoelectric constants, for both bulk and thin films. The maximum concentration of Sc for the wurtzite structure to remain ferroelectric is found to be 61 at. %. A detailed analysis of Al1−xScxN thin films reveals that the ferroelectric phase transition and properties are insensitive to substrate strain. This study lays the foundation for quantitative modeling of novel ferroelectric wurtzite solid solutions

Safety and efficacy of etomidate and propofol anesthesia in elderly patients undergoing gastroscopy: A double-blind randomized clinical study

The aim of the present study is to compare the safety, efficacy and cost effectiveness of anesthetic regimens by compound, using etomidate and propofol in elderly patients undergoing gastroscopy. A total of 200 volunteers (65–79 years of age) scheduled for gastroscopy under anesthesia were randomly divided into the following groups: P, propofol (1.5–2.0 mg/kg); E, etomidate (0.15-0.2 mg/kg); P+E, propofol (0.75–1 mg/kg) followed by etomidate (0.075-0.1 mg/kg); and E+P, etomidate (0.075-0.01 mg/kg) followed by propofol (0.75–1 mg/kg). Vital signs and bispectral index were monitored at different time points. Complications, induction and examination time, anesthesia duration, and recovery and discharge time were recorded. At the end of the procedure, the satisfaction of patients, endoscopists and the anesthetist were evaluated. The recovery (6.1±1.2 h) and discharge times (24.8±2.8 h) in group E were significantly longer compared with groups P, P+E and E+P (P<0.05). The occurrence of injection pain in group P+E was significantly higher compared with the other three groups (P<0.05). In addition, the incidence of myoclonus and post-operative nausea and vomiting were significantly higher in group P+E compared with the other three groups (P<0.05). There was no statistical difference among the four groups with regards to the patients' immediate, post-procedure satisfaction (P>0.05). Furthermore, there was no difference in the satisfaction of anesthesia, as evaluated by the anesthetist and endoscopist, among the four groups (P>0.05). The present study demonstrates that anesthesia for gastroscopy in elderly patients can be safely and effectively accomplished using a drug regimen that combines propofol with etomidate. The combined use of propofol and etomidate has unique characteristics which improve hemodynamic stability, cause minimal respiratory depression and less side effects, provide rapid return to full activity and result in high levels of satisfaction

Unconventional Superconductivity and Electron Correlations in Cobalt Oxyhydrate Na0.35_{0.35}CoO2_{2}⋅y\cdot yH2_{2}O

We report a precise $^{59}$Co nuclear quadrupolar resonance (NQR) measurement on the recently discovered cobalt oxyhydrate Na$_{0.35}$CoO$_{2}$$\cdot y$H$_{2}$O superconductor from $T$=40 K down to 0.2 K. We find that in the normal state the spin-lattice relaxation rate $1/T_1$ follows a Curie-Weiss type temperature ($T$) variation, $1/T_1T=C/(T-\theta)$, with $\theta$=-42 K, suggesting two-dimensional antiferromagnetic spin correlations. Below $T_c$=3.9 K, $1/T_1$ decreases with no coherence peak and follows a $T^n$ dependence with $n\simeq$2.2 down to $\sim$2.0 K but crosses over to a $1/T_1\propto T$ variation below $T$=1.4 K, which suggests non s-wave superconductivity. The data in the superconducting state are most consistent with the existence of line nodes in the gap function.Comment: submitted for publication in June '0

An Accurate Millimeter-Wave Imaging Algorithm for Close-Range Monostatic System

An efficient and more accurate millimeter-wave imaging algorithm, applied to a close-range monostatic personnel screening system, with consideration of dual path propagation loss, is presented in this paper. The algorithm is developed in accordance with a more rigorous physical model for the monostatic system. The physical model treats incident waves and scattered waves as spherical waves with a more rigorous amplitude term as per electromagnetic theory. As a result, the proposed method can achieve a better focusing effect for multiple targets in different range planes. Since the mathematical methods in classical algorithms, such as spherical wave decomposition and Weyl identity, cannot handle the corresponding mathematical model, the proposed algorithm is derived through the method of stationary phase (MSP). The algorithm has been validated by numerical simulations and laboratory experiments. Good performance in terms of computational efficiency and accuracy has been observed. The synthetic reconstruction results show that the proposed algorithm has significant advantages compared with the classical algorithms, and the reconstruction by using full-wave data generated by FEKO further verifies the validity of the proposed algorithm. Finally, the proposed algorithm performs as expected over real data acquired by our laboratory prototype

Na content dependence of superconductivity and the spin correlations in Na_{x}CoO_{2}\cdot 1.3H_{2}O

We report systematic measurements using the ^{59}Co nuclear quadrupole resonance(NQR) technique on the cobalt oxide superconductors Na_{x}CoO_{2}\cdot 1.3H_{2}O over a wide Na content range x=0.25\sim 0.34. We find that T_c increases with decreasing x but reaches to a plateau for x \leq0.28. In the sample with x \sim 0.26, the spin-lattice relaxation rate 1/T_1 shows a T^3 variation below T_c and down to T\sim T_c/6, which unambiguously indicates the presence of line nodes in the superconducting (SC) gap function. However, for larger or smaller x, 1/T_1 deviates from the T^3 variation below T\sim 2 K even though the T_c (\sim 4.7 K) is similar, which suggests an unusual evolution of the SC state. In the normal state, the spin correlations at a finite wave vector become stronger upon decreasing x, and the density of states at the Fermi level increases with decreasing x, which can be understood in terms of a single-orbital picture suggested on the basis of LDA calculation.Comment: version published in J. Phys. Condens. Matter (references updated and more added

B \to (\jpsi,\eta_c) K decays in the perturbative QCD approach

In this paper, we calculated the B \to (\jpsi, \eta_c) K decays in the perturbative QCD approach with the inclusion of the partial next-to-leading order (NLO) contributions. We found that (a) when the large enhancements from the known NLO contributions are taken into account, the NLO pQCD predictions for the branching ratios are the following: Br(B^0 \to \jpsi K^0) = 5.2^{+3.5}_{-2.8}\times 10^{-4}, Br(B^+ \to \jpsi K^+) = 5.6^{+3.7}_{-2.9}\times 10^{-4}, $Br(B^0 \to \eta_c K^0) = 5.5^{+2.3}_{-2.0}\times 10^{-4}$, $Br(B^+ \to \eta_c K^+) = 5.9^{+2.5}_{-2.1}\times 10^{-4}$, which are roughly 40% smaller than the measured values, but basically agree with the data within $2-\sigma$ errors; (b) the NLO pQCD predictions for the CP-violating asymmetries of B \to (\jpsi,\eta_c)K decays agree perfectly with the data.Comment: 18 pages, 3 figures, RevTex. some modifications in content,numerical results change

Quantitative trait locus (QTL) analysis of pod related traits in different environments in soybean

Soybean is an important crop, whose most agronomic traits are quantitative inherited. Mapping of these quantitative trait loci in soybean genes is importance for various applications. A F2:15 RIL population containing 149 lines derived from a cross between Charleston as female and Dongnong 594 as male parent were used for mapping of the QTL of pod related traits. Three agronomic traits showing clear phenotypic variations between parents were investigated and relevant QTLs were analyzed with software WindowsQTL Cartographer V2.5. The pod related traits are podwall thickness, weight of podwall, and ratio of podwall to pod (weight to weight). A total of 67 QTLs were mapped for 3 agronomic traits. Some QTLs identified under all environments tend to be valuable for soybean molecular marker assistant breeding selection.Key words: Soybean, pod traits, QTL, different environments

Neoformation of pedogenic carbonates by irrigation and fertilization and their contribution to carbon sequestration in soil

© 2015 Elsevier B.V. The impact of land use change and farming management on soil organic carbon (SOC) and soil inorganic carbon (SIC), particularly pedogenic carbonates (PC), was assessed in a semi-humid region of China. The SOC and SIC content and stocks were measured, and δ13C values were used to calculate the percentage of PC and lithogenic carbonates (LC) in the total SIC. Over the 39-year period, organic fertilizers at high and low rates (OFH and OFL), mineral fertilizers (MF), and a control site without fertilizers (CK) showed an increase of PC compared to a natural fallow plot (F). The main pathway of SIC accumulation was the neoformation of pedo-atmogenic carbonates contributing to C sequestration of at least 0.38, 0.27, 0.23, and 0.12MgCha-1yr-1 for the OFH, OFL, MF, and CK treatments, respectively. The LC stock remained similar in all treatments except for the CK, where LC was significantly lower than all of the other treatments which suggested dissolution. An increase in OC stocks in response to organic fertilization was not limited to the surface soil, but it continued down the soil profile to a depth of 160cm. The maximum potential for neoformation of PC depends on Ca2+ and Mg2+ availability; in this study these cations were provided by irrigation water. However, organic and mineral fertilizers modify this potential. Without organic and mineral fertilization, the PC formed at the expense of dissolution and re-precipitation of LC, even when substantial quantities of Ca2+ and Mg2+ were present in the soil. Our experimental results indicate that the neoformation of PC should be considered during estimation of soil carbon stocks and sequestration for the development of optimal fertilization, irrigation and land use practices.13