Adatom Defect Induced Spin Polarization of Asymmetric Structures

The spin polarization of carbon nanomaterials is crucial to design spintronic devices. In this paper, the first-principles is used to study the electronic properties of two defect asymmetric structures, Cap-(9, 0)-Def [6, 6] and Cap-(9, 0)-Def [5, 6]. We found that the ground state of Cap-(9, 0)-Def [6, 6] is sextet and the ground state of Cap-(9, 0)-Def [5, 6] is quartet, and the former has a lower energy. In addition, compared with Cap-(9, 0) CNTs, the C adatom on C₃₀ causes spin polarization phenomenon and Cap-(9, 0)-Def [6, 6] has more spin electrons than Cap-(9, 0)-Def [5, 6] structure. Moreover, different adsorb defects reveal different electron accumulation. This finding shows that spin polarization of the asymmetric structure can be adjusted by introducing adatom defects.     

电子束蒸发沉积Ir膜真空紫外反射特性

Ir是一种重要的真空紫外反射材料,在太阳物理、宇宙物理、生命科学、大气物理、同步辐射等方面有着十分重要的应用.对电子束蒸发沉积Ir膜在真空紫外波段的反射特性进行了系统的理论和实验研究.根据吸收材料基底上单层金属膜数学计算模型,对不同基片上各种厚度的Ir膜真空紫外反射率进行了优化计算.根据计算和前期实验结果,采用电子束蒸发方法,在石英、K9玻璃基片上沉积了不同厚度的Ir膜,在入射波长120 nm处获得了近30%正入射反射率,对应的Ir膜厚度为12 nm.过厚或过薄均不利于Ir膜反射率的提高.经退火处理后,Ir膜中张应力有所释放但并未消除,同时晶粒平均尺寸显著增大,反射率下降.     

Observation of collective atomic recoil motion in a degenerate fermion gas

We demonstrate collective atomic recoil motion with a dilute, ultracold, degenerate fermion gas in a single spin state. By utilizing an adiabatically decompressed magnetic trap with an aspect ratio different from that of the initial trap, a momentum-squeezed fermion cloud is achieved. With a single pump pulse of the proper polarization, we observe, for the first time, multiple wave-mixing processes that result in distinct collective atomic recoil motion modes in a degenerate fermion cloud. Contrary to the case with Bose condensates, no pump-laser detuning asymmetry is present.     

角分辨光电子能谱光束线1200line/mm光栅研制

国家同步辐射实验室新建了覆盖5～40 eV的低能区高分辨率角分辨光电子能谱光束线.其球面光栅单色仪包含了三块光栅,即300,600和1200 line/mm球面层式(Laminar)光栅.采用全息离子束刻蚀工艺,在硅光栅基片上成功地刻蚀出1200 line/mm、占空比0.35、槽深35 nm、有效刻划面积大于120 ...     

Highly regioselective [3 + 2] annulation of azomethine imines with 1-alkynyl Fischer carbene complexes to functionalized N,N-bicyclic pyrazolidin-3-ones

The highly regioselective [3 + 2] cycloaddition of azomethine imines to 1-alkynyl Fischer carbene complexes has been successfully realized under mild conditions. Oxidative demetalation of the newly formed pyrazolo-pyrazolone carbene complexes with pyridine-N-oxide or ceric ammonium nitrate efficiently afforded pyrazolo-pyrazolone derivatives as well as cycloprop-2-enone and trisubstituted 1H-pyrazoles in some cases, providing a novel route to versatile functionalized N,N-bicyclic pyrazolidin-3-ones.     

Stability evaluation of Tc-99m radiolabeled GRPr antagonist with amino acid chelators

In order to select a chelator with excellent stability, easier radiolabeling process and low cost, GRPr antagonist RM26 with the amino acid based chelator was radiolabeled with technetium-99m. The stability of the radiolabeled peptides in PBS, serum as well as in the presence of excess cysteine was compared.

     

Ultrathin CuF2-Rich Solid-Electrolyte Interphase Induced by Cation-Tailored Double Electrical Layer toward Durable Sodium Storage

Solid-electrolyte interphase (SEI) seriously affects battery's cycling life, especially for high-capacity anode due to excessive electrolyte decomposition from particle fracture. Herein, we report an ultrathin SEI (3–4 nm) induced by Cu⁺-tailored double electrical layer (EDL) to suppress electrolyte consumption and enhance cycling stability of CuS anode in sodium-ion batteries. Unique EDL with SO₃CF₃-Cu complex absorbing on CuS in NaSO₃CF₃/diglyme electrolyte is demonstrated by in situ surface-enhanced Raman, Cyro-TEM and theoretical calculation, in which SO₃CF₃-Cu could be reduced to CuF₂-rich SEI. Dispersed CuF₂ and F-containing compound can provide good interfacial contact for formation of ultrathin and stable SEI film to minimize electrolyte consumption and reduce activation energy of Na⁺ transport. As a result, the modified CuS delivers high capacity of 402.8 mAh g⁻¹ after 7000 cycles without capacity decay. The insights of SEI construction pave a way for high-stability electrode.     

Assembled Porphyrin-Based Multinuclear Ruthenium(II)-NNNN Complex Catalysts for Transfer Hydrogenation of Ketones

Multinuclear porphyrin-based ruthenium(II)-NNNN complexes were efficiently assembled by means of coordinatively unsaturated 16-electron mononuclear ruthenium(II)-pyrazolyl-imidazolyl-pyridine complex, zinc(II) meso-tetra(4-pyridyl)-porphyrin (ZnTPyP), and 4,4′-linked bipyridines. The resultant multinuclear (Ru₄ and Ru₈) porphyrin-based ruthenium(II)-NNNN complexes exhibited exceptionally high catalytic activity at as low as 0.008 mol % Ru loading for the transfer hydrogenation reaction of ketones in refluxing 2-propanol, reaching up to 99 % yields and 5.7×10⁶ h⁻¹ TOFs.