从原子到大分子体系的计算机模拟——计算化学50年

本文综述并修订了从20世纪50年代末至今,我们在计算化学领域所做的一些有意义的工作。序言部分把我们的工作置于当代科学的背景之下。然后我们以一种经典的基准测试体系——一种新的单粒子表象（即替代传统的原子和分子自旋轨道的化学自旋轨道）所构建的氢分子（H2）波函数——作为开始。用Hartree-Fock-Heitler-Lo...     

Broadband photonic ADC for microwave photonics-based radar receiver

A broadband photonic analog-to-digital converter(ADC) for X-band radar applications is proposed and experimentally demonstrated. An X-band signal with arbitrary waveform and a bandwidth up to 2 GHz can be synchronously sampled and processed due to the optical sampling structure. In the experiment, the chirp signal centered at 9 GHz with a bandwidth of 1.6 GHz is sampled and down-converted with a signal-to-noise ratio of 7.20 d B and an improved noise figure. Adopting the photonic ADC in the radar receiver and the above signal as the transmitted radar signal, an X-band inverse synthetic aperture radar system is set up, and the range and cross-range resolutions of 9.4 and 8.3 cm are obtained, respectively.     

Highly linear transmission and EVM improvement of vector modulation signals for radio-over-fiber applications

The principle of error vector magnitude (EVM) against modulator nonlinearity for vector modulation signal (VMS) transmission in radio-over-fiber (RoF) systems is theoretically and experimentally investigated. A highly linear modulation scheme is proposed and demonstrated using a single-drive dual parallel Mach-Zehnder modulator (MZM). This method improves EVM performance and enlarges the linear input dynamic range of the VMS transmission. An index of maximum allowable input power difference (MAIPD) that reflects the difference of upper input power limits between these two schemes is measured. An EVM limitation of 5% MAIPD has 5 dB. Both 16and 64-QAM results indicate that the proposed scheme supports VMS transmission better than the MZM one.     

Synthesis and Crystal Structure of 3,3'-Bis(5-(N-(4-hydroxylphenyl)imidomethyl)- pyrrol-2-yl)pentane·2CH_3OH

3,3'-Bis(5-(N-(4-hydroxylphenyl)imidomethyl)pyrrol-2-yl)pentane 1 has been synthesized and characterized. The crystal of its methanol complex, 1·(CH3OH)2, belongs to the orthorhombic system, space group Pccn with a = 18.094(2), b = 11.6890(16), c = 13.3629(19) , V = 2826.3(7) 3, Z = 8, C14.5H18N2O2, Mr = 252.31, Dc = 1.186 g/cm3, F(000) = 1080 and μ(MoKα) = 0.080 mm-1. The final R = 0.0662 and wR = 0.1801 for 1908 observed reflections with I 2σ(I), and R = 0.0800 and wR = 0.1948 for all reflections. In the solid state, bridged by included methanol molecules, the molecules of compound 1 form interpenetrated grid structure through N–H···O and O–H···O hydrogen bonds.     

列车防滑器主机故障诊断系统设计

SAB型列车防滑制动系统应用于国内T型列车,数量多,为了提高列车防滑器主机故障检测和维修效率,针对SAB WABCO公司的SWKAS20C型列车防滑器主机,设计了元件级故障检测与定位专家系统。通过研究模拟电子电路故障诊断技术,设计了基于支持向量机的多故障分类器,用于主机模拟电路故障样本数据的训练和测试,并通过改进算法寻优向量机参数,提高了故障诊断的准确度。搭建了模拟列车运行环境的测试平台,用以模拟主机在多种状态下的故障模式;使用VS2010开发环境编写了MFC专家系统。     

A Novel Binuclear Cu（Ⅱ） Complex with Nitroxide Radicals Exhibiting Ferromagnetic Interactions

A new binuclear Cu(Ⅱ) complex with nitronyl nitroxide radicals [Cu(NIT3Py)2Cl2]2(NIT3Py = 2-(3'-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been synthesized and structurally characterized by X-ray diffraction analysis.It crystallizes in monoclinic,space group C2/c with a = 38.483(4),b = 7.2450(8),c = 27.559(3) ,β = 134.0180(10)°,V = 5525.6(10) 3,C48H64Cl4Cu2N12O8,Mr = 1206.00,Z = 4,Dc = 1.450 g/cm3,μ(MoKα) = 1.025 mm-1,F(000) = 2504,S = 1.066,the final R = 0.0471 and wR = 0.1121 for 3286 observed reflections(I > 2σ(I)).The title complex consists of centrosymmetric dinuclear units [Cu(NIT3Py)2Cl2]2,in which the copper ions are square-pyramidally coordinated by two pyridyl nitrogen atoms of two radical ligands and three chlorine anions,two of which bridge the copper ions.The magnetic measurements show ferromagnetic interactions between the copper ions and the radical ligands.     

Heterometallic Trinuclear Ni2Zn and Ni2Mn Complexes of Macrocyclic Oxamide: Synthesis and Crystal Structures

Two novel heterometallic trinuclear complexes of macrocyclic oxamide [Mn(NiL)2(HBTC)H2O] (1) and [Zn(NiL)2(HBTC)H2O] (2) (NiL, H2L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien, H3BTC = 1,3,5-benzenetricarboxylic acid) have been solvothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. For 1, the crystals crystallize in the monoclinic system, space group P21/c with a = 11.3595(5), b = 23.1498(11), c = 17.2558(8) and =101.2530(10)°. For 2, the crystals crystallize in the monoclinic system, space group P21/c with a = 11.5214(8), b = 20.6566(14), c = 18.4126(13)  and = 92.6770(10)°. The structures of 1 and 2 have oxamido-bridged trinuclear [NiⅡ2MⅡ] units and consist of two-dimensional supramolecular architectures formed by strong O-H…O intermolecular hydrogen bonds.     

一种具有吡咯酰胺和脲的杂双位点受体的选择性氟离子比色识别

本文合成了一种具有吡咯酰胺和脲杂双识别位点的阴离子受体。利用紫外光谱法研究了该受体在乙腈溶液中对阴离子的识别作用。结果表明,该受体的识别能力比具有两个相同识别位点的受体的阴离子识别能力有所提高。同时,当仅当添加氟离子时,受体溶液的颜色会从无色变为黄色。表明,受体在氟离子的选择比色传感方面具有潜在的应用能力。     

两个含1-苄基咪唑的Zn(Ⅱ)和Cu(Ⅱ)新配合物:合成和结构研究(英文)

1-苄基咪唑(L)与对苯二甲酸和Zn(NO_3)_2·6H_2O反应生成一维聚合链[ZnL_2(TP)]_n(1),在这个配合物中通过链间的C-H…π相互作用形成了二维超分子层。1-苄基咪唑(L)和CuCl_2·2H_2O反应生成四核配合物[Cu_4(μ_4-O)Cl_6L_4](2),在这个配合物中通过C-H…Cl氢键形成了一维超分子链。测定了L,1和2的荧光发射光谱。