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用线圈电流控制非平衡磁场,用汤森放电击穿形成深度自触发放电,用磁阱捕获放电形成的二次电子和导致漂移电流,形成了高功率非平衡磁控溅射放电。采用偏压为-100V相对磁控靶放置的圆形平面电极收集饱和离子电流;在距离磁控靶14cm的位置由Langmuir探针测量浮置电位;示波器测量磁控靶的脉冲电压、电流、浮置电位和饱和离子电流信号。装置的放电脉冲功率达到0.9MW,脉冲频率最大值为40Hz左右,空间电荷限制条件是控制电子电流和离子电流的主要机制。     

基于毕达哥拉斯犹豫模糊距离测度的灰关联双向投影决策法

为解决多属性决策单方向偏差难题所提出的灰关联投影法尚存在适用性差的技术不足。为此,在借鉴双向投影技术要点的基础上联合新型灰关联系数,并引入毕达哥拉斯犹豫模糊集的表达优势,提出基于毕达哥拉斯犹豫模糊距离测度的灰关联双向投影决策方法。新方法能够有效解决毕达哥拉斯犹豫模糊多属性决策问题,具有较高的分辨度。通过算例应用分析,直接验证了毕达哥拉斯犹豫模糊灰关联双向投影方法的实用性,间接验证了毕达哥拉斯犹豫模糊距离测度和灰关联双向投影法的有效性。     

A salt-free zero-charged aqueous onion-phase enhances the solubility of fullerene C60 in water

An onion-phase (multilamellar vesicular phase or Lalpha-phase) was prepared from salt-free zero-charged cationic and anionic (catanionic) surfactant mixtures of tetradecyltrimethylammonium hydroxide (TTAOH)/lauric acid (LA)/H2O. The H+ and OH- counterions form water (TTAOH + LA --> TTAL + H2O), leaving the solution salt free. The onion-phase solution has novel properties including low conductivity, low osmotic pressure and unscreened electrostatic repulsions between cationic and anionic surfactants because of the absence of salt. The spherical multilamellar vesicles have an average 250 nm radius as measured by freeze-fracture transmission electron microscopy (FF-TEM) and the maximum interlayer distance, i.e., the thickness of the hydrophobic bilayer and the water layer, was calculated to be around 52 nm by small-angle X-ray scattering (SAXS). Extremely hydrophobic C60 fullerene can be solubilized in this salt-free zero-charged aqueous onion-phase. As a typical result, 0.588 mg.mL(-1) (approximately 0.82 mmol.L(-1)) C60 has been successfully solubilized into a 50 mmol.L(-1) catanionic surfactant onion-phase aqueous solution. The weight ratio of fullerene to TTAL is calculated to be around 1:40. Solubilization of C60 in the salt-free catanionic onion-phase solution was investigated by using different sample preparation routes, and a variety of techniques were used to characterize these vesicular systems with or without encapsulated C60. The onion-phase solution changed color from slightly bluish to yellow or brown after C60 was solubilized. 1H and 13C NMR measurements indicated that the C60 molecules are located in the hydrophobic layers, i.e., in the central positions [omega-CH3 and delta-(CH2)x] of the hydrophobic layers of the TTAL onion-phase. Salt-free zero-charged catanionic vesicular aqueous solutions are good candidates for enhancing the solubility of C60 in aqueous solutions and may broaden the functionality of fullerenes to new potential applications in biology, medicine, and materials. Hopefully, our method can also be extended to solubilize functionalized carbon nanotubes in aqueous solutions.     

Co1-xS embedded in porous carbon derived from metal organic framework as a highly efficient electrocatalyst for oxygen evolution reaction

Here, we report a two-step conversion method to fabricate a composite of Co_1-xS embedded in porous carbon framework (Co_1-xS@C) derived from metal organic frameworks (MOFs). The as-prepared porous dodecahedron Co_1-xS@C composite catalyst exhibits excellent electrocatalytic performance towards oxygen evolution reaction (OER).     

Crystal Structures and Electrochemical Properties of R1.5Ca1.5MgNi14(R=Nd,Gd and Er)Hydrogen Storage Alloys

Ca₃MgNi₁₄, Nd_1.5Ca_1.5MgNi₁₄, Gd_1.5Ca_1.5MgNi₁₄ and Er_1.5Ca_1.5MgNi₁₄ alloys were prepared by high frequency induction melting and sintering. Characterization and analysis were performed by X-ray diffraction/Rietveld full-spectrum fitting, gaseous P-C-T hydrogen storage test and electrochemical properties tests. It can be found that all alloys consist of Gd₂Co₇-type 3R phase and Ce₂Ni₇-type 2H phase. Although the hydrogen storage capacities of Nd_1.5Ca_1.5MgNi₁₄, Gd_1.5Ca_1.5MgNi₁₄ and Er_1.5Ca_1.5MgNi₁₄ decrease to some extent compared to that of Ca₃MgNi₁₄, their equilibrium pressures for absorption and desorption increase markedly. Moreover, R_1.5Ca_1.5MgNi₁₄ alloys have better cycling stabilities and high-rate discharge(HRD) properties as compared to Ca₃MgNi₁₄. The hydrogen diffusion in alloy electrodes is the main factor to influence the HRD performance.     

北京谱仪III上利用神经网络方法进行粒子鉴别的研究

本文描述了一种多层感知器的神经网络系统在BESIII粒子鉴别技术中的应用。网络按照子探测器分别进行训练, 输出结果可以作为后续网络的输入或者可以为似然函数方法构建概率密度函数。蒙特卡罗模拟样本的检验结果表明, 利用神经网络方法可以在BESIII上获得较好的粒子鉴别效果。     

Dependence of Crystal Quality and β Value on Synthesis Temperature in Growing Gem Diamond Crystals

High quality Ib gem diamond single crystals were synthesized in cubic anvil high-pressure apparatus （SPD- 6 × 1200） under 5.4GPa and 1230℃-1280℃. The （100） face of seed crystal was used as growth face, and Ni70Mn25Co5 alloy was used as solvent/catalyst. The dependence of crystal quality andβ value （the ratio of height to diameter of diamond crystal） on synthesis temperature was studied. When the synthesis temperature is between 1230℃ and 1280℃, theβ value of the synthetic high-quality gem diamond crystals is between 0.4 and 0.6. The results show that when theβ value is between 0.4 and O. 45, the synthetic diamonds are sheet-shape crystals; however, when theβ value is between 0.45 and 0.6, the synthetic diamonds are tower-shape crystals. In addition, when theβ value is less than 0.4, skeleton crystals will appear. When theβ value is more than 0.6, most of the synthetic diamond crystals are inferior crystals.     

（Na0.52K0.44Li0.04）Nb0.9-xSbxTa0.1O3 Lead-Free Piezoelectric Ceramics with High Performance and High Curie Temperature

（Na0.52K0.44Li0.04）Nb0.9-x Sbx Ta0.1O3 lead-free piezoelectric ceramics are prepared by a solid-state reaction method. With increasing Sb content, the transition temperature from orthorhombic to tetragonal polymorphic phase decreased. A composition （Na0.52K0.44Li0.04）Nb0.863Sb0.037Ta0.1O3 is found to possess excellent piezo- electric and electromechanical performances （d33 = 306pC/N, kp =48%, and kt=50%）, and high Curie temperature （Tc = 320 ℃）. These results indicate that （Na0.52K0.44Li0.04）Nb0.863Sb0.037 Ta0.1O3 is a promising lead-free piezoceramics replacement for lead zirconate titanate.     

Symmetric Telecloning and Entanglement Distribution of Spin Quantum States

We propose a physical realization of symmetric telecloning machine for spin quantum states. The concept of area average fidelity is introduced to describe the telecloning quality. It is indicated that for certain input states this quantity may come to an enough high level to satisfy the need of quantum information processing. We also study the properties of entanglement distribution via the spin chain for arbitrary two-qubit entangled pure states as inputs and find that the decay ratio of entanglement for the output states is only determined by the parameters of spin chain and waiting time, independent of the initial input states.     

Effects of Li Substitution and Sintering Temperature on Properties of Bi0.5（Na,K）0.5TiO3 Lead-Free Piezoelectric Ceramics

Bi0.5 （Na0.72K0.28- x Lix ）0.5 TiO3 （BNKLT- 100x） lead-free piezoelectric ceramics are synthesized by conventional solid state sintering techniques. The dielectric and piezoelectric properties of the BNKLT-100x ceramics as a function of Li content are systematically investigated. It is found that not only Li content but also the sintering temperature has a strong effect on the piezoelectric properties of BNKLT. The piezoelectric constant d33 Of BNKLT varies from 120 to 252pC/N in the Li content range from 0.03 to 0.16. In the sintering temperature range from 1080 to 1130℃, the d33 value of BNKLT-6 changes from 200pC/N to 252pC/N. The BNKLT-6 sample sintered at 1100℃ has the highest piezoelectric constant d33 of 252pC/N, with the electromechanical coupling factors kp of 0.32 and kt of 0.44.