纳米多孔银力学性能表征分子动力学模拟

纳米多孔金属拥有优异的物理、化学性能,在众多领域中极具应用前景.相关力学性能的认知是实现其功能化应用的重要基础之一.基于分子动力学模拟,以三种拓扑结构(立方体结构、金刚石结构、螺旋体结构)的纳米多孔银为对象,研究了单轴拉伸下的力学响应,探讨了拓扑结构和相对密度与其力学性能的内在联系.仿真结果表明,纳米多孔银的极限强度和杨氏模量随相对密度增大而增大的同时,还紧密地依赖于拓扑结构.其中,金刚石结构与螺旋体结构的模量随相对密度的变化趋势较为相近,而螺旋体结构中螺旋形式的孔棱在受力拉直的过程中抵抗变形,表现出相对较好的塑性.立方体结构中,孔棱分布形式单一,抵抗变形的能力较弱,模量值较低.同一相对密度下,金刚石结构的强度最大,立方体结构次之,螺旋体结构最小.金刚石结构中,交错的孔棱间形成三角骨架结构,具有一定的稳定性,表现出相对较高的强度.     

基态α-环己二酮最优解离路径中环状异构体的红外光谱分析

在CCSD(T)//B3LYP/6-311++G(d,p)理论水平上研究了基态α-环己二酮（α-CHD）到环戊酮（c-C5H8O）和一氧化碳（CO）的光解离反应势能面（PES）,并计算了沿反应路径各环状异构体的红外光谱。从过渡态的相对能量、高能势垒的数目两个方面,并结合红外光谱研究结果确定了α-CHD→c-C5H8O+CO的最优光解离路径。对其势能面上的环状异构体进行了红外光谱分析,给出各异构体的振动频率、振动强度和主要的振动模式,与实验结果吻合较好。计算结果为基态α-CHD提出了一条新的最优解离路径,同时丰富了其环状异构体的光谱信息。     

Search for a lighter Higgs boson in the Next-to-Minimal Supersymmetric Standard Model

Following the discovery of the Higgs boson with a mass of approximately 125 Ge V at the LHC, many studies have been performed from both the theoretical and experimental viewpoints to search for a new Higgs Boson that is lighter than 125 Ge V. We explore the possibility of constraining a lighter neutral scalar Higgs boson h_1 and a lighter pseudo-scalar Higgs boson a_1 in the Next-to-Minimal Supersymmetric Standard Model by restricting the next-to-lightest scalar Higgs boson h_2 to be the one observed at the LHC after applying the phenomenological constraints and those from experimental measurements. Such lighter particles are not yet completely excluded by the latest results of the search for a lighter Higgs boson in the diphoton decay channel from LHC data. Our results show that some new constraints on the Next-to-Minimal Supersymmetric Standard Model could be obtained for a lighter scalar Higgs boson at the LHC if such a search is performed by experimental collaborations and more data. The potentials of discovery for other interesting decay channels of such a lighter neutral scalar or pseudo-scalar particle are also discussed.     

Study of new boson W_1~± in the Minimal Higgsless Model at the LHC

The Minimal Higgsless Model predicts the existence of new vector gauge boson W1± . By the process PP → W1± qq → W±Z0qq, Z0 → l+l-, W±→ qq (l=e,μ; q is hadronized to be jets), we study the sensitivity of searching for this possible vector gauge boson in the level of generator events of signal and backgrounds, then give integrated luminosity required to discover 5σ signal as a function of W1± mass. The generator for the signal PP→W1± qq→W±Z0qq at tree level is developed with the Minimal Higgsless Model and then interfaced with PYTHIA for the parton showers and hadronization. The backgrounds are produced with MadGraph and PYTHIA.     

基于多壁碳纳米管的三电极血乙醇生物传感器的研究

采用丝网印刷技术在PVC基板上印制三电极,将多壁碳纳米管、麦尔多拉蓝、乙醇脱氢酶(ADH)以及氧化型辅酶Ⅰ(NAD+)依次修饰在工作电极表面,然后在该三电极表面贴一层亲水膜,形成一个5μL反应池,制成血乙醇检测新型生物传感器检测条。结果表明,此生物传感器具有良好的准确性和稳定性;检测线性范围为0.5～20mmol/L,r=0.99493;检出限为0.22mmol/L;电流达到95%稳态时间小于15s。考察了pH值、温度及干扰物对生物传感器的影响。用此生物传感器和顶空气相色谱法对10份全血标本乙醇浓度平行测试,两者相关性良好r=0.97583。利用虹吸现象吸取微量全血直接定量测定乙醇浓度是此生物传感器的特点。     

On the detectability of Galactic dark matter annihilation into monochromatic gamma-rays

Monochromatic γ-rays are thought to be the smoking gun signal for identifying dark matter annihilation. However, the flux of monochromatic γ-rays is usually suppressed by virtual quantum effects since dark matter should be neutral and does not couple with γ-rays directly. In this work, we study the detection strategy of the monochromatic γ-rays in a future space-based detector. The flux of monochromatic γ-rays between 50 GeV and several TeV is calculated by assuming the supersymmetric neutralino as a typical dark matter candidate. The detection both by focusing on the Galactic center and in a scan mode that detects γ-rays from the whole Galactic halo are compared. The detector performance for the purpose of monochromatic γ-ray detection, with different energy and angular resolution, field of view, and background rejection efficiencies, is carefully studied with both analytical and fast Monte-Carlo methods.     

Application of the parametric for mulae for electromagnetic showers in unconverted γ/π~0 discrimination

In the LHC experiment, the neutral pions produced during jet fragmentation are the background sources for all physics channels with high-energy photons in their final state. In this paper, the application of the three-dimensional parametric formula for electromagnetic (EM) showers, which we developed in the Alpha Magnetic Spectrometer II experiment, is presented to distinguish the unconverted photons from the neutral pions. With the constructed electromagnetic calorimeter (ECAL) in a GEANT4 simulation, the parametric formulae were validated and the unconverted γπ⁰ discrimination was performed with the Toolkit for Multivariate Data Analysis (TMVA) package in ROOT for different transverse energies ranging from 15 GeV to 75 GeV, which is the most sensitive region for light Higgs (with mass ～120 GeV) searches with the channel H→γγ. With this discrimination method and the selected transverse energy region, we can reject π⁰ with the efficiency from ～40% (65--75 GeV) to ～90% (15--25 GeV) when keeping 90% γ efficiency.     

Preparation of N-Acetyl-2-arylglycin Esters by N-H Insertion Reaction of Aryldiazoacetates with Acetamide

The intermolecular N-H insertion reaction of methyl α-diazo α-arylacetate with acetamide has been investigated using transition-metal complexes as catalysts. The Cu(II) complex Cu(hfacac)₂ (hfacac represents hexafluoroacetylacetonate) has proven to be the most active catalyst to yield methyl N-acetyl-2-phenylglycin in good isolated yield (73–80%) with 3 mmol% of catalyst loading in reflux toluene. The catalyst is also valuable to the substituted aryldiazoacetates at the 4-position on phenyl ring.     

A novel non-dripping oligomeric flame retardant for polyethylene terephthalate

An oligomer or low polymer, polysulfonyldiphenylene thiophenylphosphonate (PSTPP), was synthesized from phenylphosphonothioic dichloride (PPTD) and 4,4^′-sulfonyldiphenol (SDP) by polycondensation reaction. Its structures and thermal behaviors were studied using infrared spectrophotometer and thermal gravimetric analysis, respectively. This novel oligomer can be used as the flame retardant for poly(ethylene terephthalate) (PET). PET samples containing PSTPP can reach an oxygen index (OI) of 29 and a UL-94 V-0 rating when the phosphorus content of the sample is 2.5 wt%. No melting dripping was observed during the UL-94 flame test.     

Synthesis and characterization of QD-3: the first organically templated aluminoborate with 11-, 12-, and 14-ring intersecting channels

QD-3, a novel aluminoborate (TETA) 2[Al 2B 10 O 20].0.25H 2O (TETA = triethylenetetramine), has been solvothermally synthesized and characterized by IR, thermogravimetric analysis, power X-ray diffraction, elemental analysis, and single-crystal X-ray diffraction. This compound crystallizes in the orthorhombic system, space group Pna2 1 (No. 33), a = 25.9174(2) A, b = 7.4028(5) A, c = 17.013(4) A, V = 3264.2(2) A (3), and Z = 4. Its structure consists of AlO 4 tetrahedra and B 5O 10 clusters, which are interconnected and form a three-dimensional framework with large 11-, 12-, and 14-ring channels.