Facile Synthesis of Carbon-Coated Zn 2

Carbon-coated Zn2SnO4 nanomaterials have been synthesized by a facile hydrothermal method in which as-prepared Zn2SnO4 was used as the precursor and glucose as the carbon source. The structural, morphological, and electrochemical properties were investigated by means of X-ray (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical measurement. The first discharge/charge capacity of carbon-coated Zn2SnO4 was about 1248.8 mAh/g and 873.2 mAh/g at a current density of 200 mA/g in the voltage range of 0.05 V–3.0 V, respectively, corresponding to Coulombic efficiency of 69.92%. After 40 cycles, the capacity retained 400 mAh/g, which is much better than bare Zn2SnO4

Conservation and diversification of the miR166 family in soybean and potential roles of newly identified miR166s

Identity between pre-miR166s in soybean. (TIF 5906 kb

Effects of Fe on microstructures and mechanical properties of Ti-15Nb-25Zr-(0, 2, 4, 8)Fe alloys prepared by spark plasma sintering

Biomedical Ti-15Nb-25Zr-(0, 2, 4, 8)Fe (mol%) alloys are prepared by mixing pure element powders and spark plasma sintering (SPS). Specimens with diameters of 20 mm and thicknesses of 3 mm are obtained by sintering at 1000°C for 10 min followed by cooling in the furnace. Some of the specimens are then heat-treated at 900°C for 1 h followed by water quenching. Zr and Fe are dissolved in Ti; however, segregation of Nb is observed in all of the alloys. The β and α′′ phases are observed in the as-sintered and heat-treated specimens owing to the insufficient diffusion of the alloying elements. Fe stabilizes the β phase and provides a solution-strengthening effect. With the increase in the Fe content in the as-sintered specimen, the compressive strength and micro-Vickers hardness are improved in the Ti-15-Nb-25Zr-(0, 2, 4)Fe alloys and slightly decreased in Ti-15-Nb-25Zr-8Fe. The as-sintered Ti-15Nb-25Zr-4Fe alloy exhibits the maximum compressive strength of 1740 MPa. Although the plasticity is decreased by the Fe addition, a fracture strain of approximately 17% is obtained for Ti-15Nb-25Zr-4Fe, indicating a good plasticity. The heat treatment cannot eliminate the segregation of Nb, but can improve the plasticity and slightly increase the strengths of Ti-15Nb-25-Zr(0, 2, 4)Fe. Moreover, the heat-treated Ti-15Nb-25Zr-8Fe exhibits a high strength of approximately 1780 MPa and fracture strain of approximately 19%. Therefore, good comprehensive mechanical properties, including high strengths, high hardnesses, and good plasticities, can be obtained in Fe-added β-Ti alloys prepared by SPS and subsequent optional short heat treatment.Li Q., Yuan X., Li J., et al. Effects of Fe on microstructures and mechanical properties of Ti-15Nb-25Zr-(0, 2, 4, 8)Fe alloys prepared by spark plasma sintering. Materials Transactions 60, 1763 (2019); https://doi.org/10.2320/matertrans.ME201913

Experimental and Numerical Evaluation of Rock Dynamic Test with Split-Hopkinson Pressure Bar

Feasibility of rock dynamic properties by split-Hopkinson pressure bar (SHPB) was experimentally and numerically evaluated with ANSYS/LS-DYNA. The effects of different diameters, different loading rates, and different propagation distances on wave dispersion of input bars in SHPB with rectangle and half-sine wave loadings were analyzed. The results show that the dispersion effect on the diameter of input bar, loading rate, and propagation distance under half-sine waveform loading is ignorable compared with the rectangle wave loading. Moreover, the degrees of stress uniformity under rectangle and half-sine input wave loadings are compared in SHPB tests, and the time required for stress uniformity is calculated under different above-mentioned loadings. It is confirmed that the stress uniformity can be realized more easily using the half-sine pulse loading compared to the rectangle pulse loading, and this has significant advantages in the dynamic test of rock-like materials. Finally, the Holmquist-Johnson-Concrete constitutive model is introduced to simulate the failure mechanism and failure and fragmentation characteristics of rock under different strain rates. And the numerical results agree with that obtained from the experiment, which confirms the effectiveness of the model and the method

VC-Dimension of Hyperplanes over Finite Fields

Let $\mathbb{F}_q^d$ be the $d$-dimensional vector space over the finite field with $q$ elements. For a subset $E\subseteq \mathbb{F}_q^d$ and a fixed nonzero $t\in \mathbb{F}_q$, let $\mathcal{H}_t(E)=\{h_y: y\in E\}$, where $h_y$ is the indicator function of the set $\{x\in E: x\cdot y=t\}$. Two of the authors, with Maxwell Sun, showed in the case $d=3$ that if $|E|\geq Cq^{\frac{11}{4}}$ and $q$ is sufficiently large, then the VC-dimension of $\mathcal{H}_t(E)$ is 3. In this paper, we generalize the result to arbitrary dimension and improve the exponent in the case $d=3$.Comment: 9 pages, 1 figur

Low springback and low Young’s modulus in Ti-29-Nb-13Ta-4.6Zr alloy modified by Mo addition

Deformation-induced higher Young’s modulus can satisfy the contradictory requirements of Ti alloys for spinal-fixation applications, which demand a high Young’s modulus to reduce springback during operations and a low Young’s modulus to prevent stress shielding effect for patients after surgeries. In this study, TNTZ-(1, 3, 5)Mo are designed by adding Mo and Ti to Ti-29-Nb-13Ta-4.6Zr (TNTZ) in order to maintain low initial Young’s modulus and achieve low springback. All the solutionized alloys show single β phase with increasing the β stability by Mo addition. They show low Young’s moduli less than 65 GPa, similar ultimate tensile strength of 650 MPa and elongation around 20%. The springback of TNTZ-3Mo and TNTZ-5Mo is lower than that of TNTZ and TNTZ-1Mo owing to their more stable β phase. After cold rolling, TNTZ-3Mo shows the largest increasing ratio of 25% in Young’s modulus and the highest ultimate tensile strength owning to the appearance of deformation-induced ω phase. With the low initial Young’s modulus of 59 GPa, TNTZ-3Mo is a potential candidate to make the spinal rods in spinal fixation devices.Li Q., Qi Q., Li J., et al. Low springback and low Young’s modulus in Ti-29-Nb-13Ta-4.6Zr alloy modified by Mo addition. Materials Transactions 60, 1755 (2019); https://doi.org/10.2320/matertrans.ME201912

Precise Measurements of Branching Fractions for Ds+D_s^+ Meson Decays to Two Pseudoscalar Mesons

We measure the branching fractions for seven $D_{s}^{+}$ two-body decays to pseudo-scalar mesons, by analyzing data collected at $\sqrt{s}=4.178\sim4.226$ GeV with the BESIII detector at the BEPCII collider. The branching fractions are determined to be $\mathcal{B}(D_s^+\to K^+\eta^{\prime})=(2.68\pm0.17\pm0.17\pm0.08)\times10^{-3}$, $\mathcal{B}(D_s^+\to\eta^{\prime}\pi^+)=(37.8\pm0.4\pm2.1\pm1.2)\times10^{-3}$, $\mathcal{B}(D_s^+\to K^+\eta)=(1.62\pm0.10\pm0.03\pm0.05)\times10^{-3}$, $\mathcal{B}(D_s^+\to\eta\pi^+)=(17.41\pm0.18\pm0.27\pm0.54)\times10^{-3}$, $\mathcal{B}(D_s^+\to K^+K_S^0)=(15.02\pm0.10\pm0.27\pm0.47)\times10^{-3}$, $\mathcal{B}(D_s^+\to K_S^0\pi^+)=(1.109\pm0.034\pm0.023\pm0.035)\times10^{-3}$, $\mathcal{B}(D_s^+\to K^+\pi^0)=(0.748\pm0.049\pm0.018\pm0.023)\times10^{-3}$, where the first uncertainties are statistical, the second are systematic, and the third are from external input branching fraction of the normalization mode $D_s^+\to K^+K^-\pi^+$. Precision of our measurements is significantly improved compared with that of the current world average values

Measurement of branching fractions of Λc+\Lambda_{c}^{+} decays to Σ+K+K−\Sigma^{+} K^{+} K^{-}, Σ+ϕ\Sigma^{+}\phi and Σ+K+π−(π0)\Sigma^{+} K^{+} \pi^{-}(\pi^{0})

Based on 4.5 fb$^{-1}$ data taken at seven center-of-mass energies ranging from 4.600 to 4.699 GeV with the BESIII detector at the BEPCII collider, we measure the branching fractions of $\Lambda_{c}^{+}\rightarrow\Sigma^{+}+hadrons$ relative to $\Lambda_{c}^{+}\rightarrow \Sigma^+ \pi^+ \pi^-$. Combining with the world average branching fraction of $\Lambda_{c}^{+}\rightarrow \Sigma^+ \pi^+ \pi^-$, their branching fractions are measured to be $(0.377\pm0.042\pm0.018\pm0.021)\%$ for $\Lambda_{c}^{+}\rightarrow\Sigma^{+} K^{+} K^{-}$, $(0.200\pm0.023\pm0.010\pm0.011)\%$ for $\Lambda_{c}^{+}\rightarrow\Sigma^{+} K^{+} \pi^{-}$, $(0.414\pm0.080\pm0.029\pm0.023)\%$ for $\Lambda_{c}^{+}\rightarrow\Sigma^{+}\phi$ and $(0.197\pm0.036\pm0.008\pm0.011)\%$ for $\Lambda_{c}^{+}\rightarrow\Sigma^{+}K^{+} K^{-}$(non-$\phi$). In all the above results, the first uncertainties are statistical, the second are systematic and the third are from external input of the branching fraction of $\Lambda_{c}^{+}\rightarrow \Sigma^+ \pi^+ \pi^-$. Since no signal for $\Lambda_{c}^{+}\rightarrow\Sigma^{+} K^{+} \pi^{-}\pi^{0}$ is observed, the upper limit of its branching fraction is determined to be 0.11\% at the 90$\%$ confidence level