微波消解、ICP-AES快速测定污泥中的铜、铅、锌、镉、铬、镍、锰和磷

本文采用微波消解样品、电感耦合等离子体 -原子发射光谱法 (ICP- AES)快速测定城市污泥中农用控制微量元素 Cu、Pb、Zn、Cr、Cd、Ni、Mn及有效肥料元素 P的含量 ,各分析元素的回收率在 96 .3%—10 4 %之间 ,相对标准偏差小于 4 .3% ,方法快速简便、准确度高、精密度好 ,结果令人满意。     

A Study on the Correlation Between Poles and Cuts in ππ Scattering

In this paper we propose a dispersive method to describe two-body scattering with unitarity imposed. This approach is applied to elastic ππ scattering. The amplitudes keep single-channel unitarity and describe the experimental data well, and the low-energy amplitudes are consistent with that of chiral perturbation theory. The pole locations of the σ, f0(980), ρ(770) and f2(1270) and their couplings to ππ are obtained. A virtual state appearing in the isospin-two S-wave is confirmed. The correlations between the left(and right) hand cut and the poles are discussed. Our results show that the poles are more sensitive to the right hand cut rather than the left hand cut. The proposed method could be used to study other two-body scattering processes.     

The Phase Transition of Eu2O3 under High Pressures

Pressure-induced phase transition of cubic Eu2 03 is studied by angle-dispersive x-ray diffraction （ADXD） up to 42.3 GPa at room temperature. A structural transformation from a cubic phase to a hexagonal phase is observed, which starts at 5.0 GPa and finishes at about 13.1 GPa. The phase transition leads to a volume collapse of 9.0% at 8.6 GPa. The hexagonal phase of Eu2 03 maintains stable up to the highest experiment pressure. After re/ease of pressure, the high-pressure phase transforms to a monoclinic phase. The pressure-volume data are fitted with the Birch-Murnaghan equation of state. The bulk moduli obtained upon compression from the fitting are 145（2） GPa and 151（6） OPa for the cubic and hexagonal phases, respectively, when their first pressure derivatives are fixed at 4.     

白簕多糖的提取工艺和含量比较

经多糖确证性实验首次证明白簕中含有多糖成分,不同部位的多糖含量不同,白簕中茎皮的多糖含量最高。单因素实验法对影响多糖得率的主要因素进行了分析,正交实验优化了多糖提取的工艺条件,研究表明：白簕茎皮中提取多糖类成分的最佳条件为：辐射时间60s、料液比1∶20、醇沉浓度70%、提取次数3次。在最佳条件下总多糖的含量为6.28mg/g。     

An Integrative Biosensor Based on Contra-Directional Coupling Two-dimensional Photonic Crystal Waveguides

We propose an integrative biochemical sensor utilizing the dip in the transmission spectrum of a normal singleline defect photonic crystal （PC） waveguide, which has a eontra-directional coupling with another PC waveguide. When the air holes in the PC slab are filled with a liquid analyte with different refractive indices, the dip has a wavelength shift. By detecting the output power variation at a certain fixed wavelength, a sensitivity of 1.2 × 10^-4 is feasible. This structure is easy for integration due to its plane waveguide structure and omissible pump source. In addition, high signal to noise ratio can be expected because signal transmits via a normal single-line defect PC waveguide instead of the PC hole area or analyte.     

Temporal shifting: a hidden key to the skewed peak puzzle

The recorder-provided peak position for flow-type chemical instruments has been verified mathematically as being comprised of a "spatially-non-existent" shift, which is generated due to the relativity in accounting for the detection at a fixed point. This shift, denoted as Phi, can be approximated by Phi approximately 0.5micro(t)2, where micro(t) is the temporal expanding coefficient of the system given. For flow injection analysis, the shift is correlated to a longitudinal dispersion coefficient D and the flow speed u, i.e., Phi approximately D/u2. For linear chromatography, it is correlated to a dynamic partition ratio k' and a scaling factor f of the column used, i.e., Phi approximately 0.5k'f. In combination, the temporal shift can be expressed as Phi approximately 0.5k'f+D(k'+1)2/u2. Although the shift may be small in scale, it provides a clue to decipher the basic parameters from a recorded peak. Under a linear isotherm, this parameter can be estimated readily from an experimental peak following a very simple procedure.     

New members of a class of iron-thiolate-nitrosyl compounds: trinuclear iron-thiolate-nitrosyl complexes containing Fe(3)S(6) core

The neutral trinuclear iron-thiolate-nitrosyl, [(ON)Fe(mu-S,S-C(6)H(4))](3) (1), and its oxidation product, [(ON)Fe(mu-S,S-C(6)H(4))](3)[PF(6)] (2), were synthesized and characterized by IR, X-ray diffraction, X-ray absorption, electron paramagnetic resonance (EPR), and magnetic measurement. The five-coordinated, square pyramidal geometry around each iron atom in complex 1 remains intact when complex 1 is oxidized to yield complex 2. Magnetic measurements and EPR results show that there is only one unpaired electron in complex 1 (S(total) = 1/2) and no unpaired electron (S(total) = 0) in 2. The detailed geometric comparisons between complexes 1 and 2 provide understanding of the role that the unpaired electron plays in the chemical bonding of this trinuclear complex. Significant shortening of the Fe-Fe, Fe-N, and Fe-S distances around Fe(1) is observed when complex 1 is oxidized to 2. This result implicates that the removal of the unpaired electron does induce the strengthening of the Fe-Fe, Fe-N, and Fe-S bonds in the Fe(1) fragment. A significant shift of the nuNO stretching frequency from 1751 cm(-1) (1) to 1821, 1857 cm(-1) (2) (KBr) also indicates the strengthening of the N-O bonds in complex 2. The EPR, X-ray absorption, magnetic measurements, and molecular orbital calculations lead to the conclusion that the unpaired electron in complex 1 is mainly allocated in the Fe(1) fragment and is best described as {Fe(1)NO}7, so that the unpaired electron is delocalized between Fe and NO via d-pi* orbital interaction; some contributions from [Fe(2)NO] and [Fe(3)NO] as well as the thiolates associated with Fe (1) are also realized. According to MO calculations, the spin density of complex 1 is predominantly located at the Fe atoms with 0.60, -0.15, and 0.25 at Fe(1), Fe(2), and Fe(3), respectively.     

基于衣康酸配体构筑的两个锌配合物的合成、结构和荧光性质

通过水热法合成了两种锌配位聚合物{[Zn（ic）（bip）]·2H₂O}_n（1）和[Zn（ic）（bpe）]_n（2）（H₂ic=衣康酸,bip=3,5-二（1-咪唑基）吡啶,bpe=1,2-二（4-吡啶基）乙烯）,并通过X射线单晶衍射和元素分析对其结构进行了表征。配合物1和2均为含有一维金属-羧酸链的二维（4,4）格子层结构。此外,对它们的热重、粉末X射线衍射和固体荧光性能进行了考察。与配体bip相比,1的发射光谱发生了明显的蓝移（⁷8 nm）,可能归因于配体到金属的电荷转移;2显示与游离的bpe配体相似的荧光性质,轻微的红移可能是因为与金属离子之间的配位作用导致的。     

空气污染各组分对甲烷超声速燃烧性能的影响

在与甲烷详细化学反应机理对比验证基础上,采用18组分24步简化反应机理模拟甲烷超声速燃烧过程,从化学动力学和热力学角度用数值方法研究了乙醇燃烧加热空气中的七种主要污染组分(H2O,CO2,O,OH,CO,H,H2)对甲烷超声速燃烧性能的影响.分析结果表明:在一定条件下,进口空气中污染组分H2O的增加造成平均比热容增加,总温降低,并作为第三体抑制甲烷的燃烧过程,使超燃室的性能下降;CO2因大分子量特性使燃气平均分子量增大,降低超燃室做功能力,H2O和CO2两组分对甲烷超燃性能都起消极作用;污染组分自由基H、O、OH和燃烧中间产物CO、H2使燃烧室燃烧效率上升,对甲烷超燃性能起积极作用.     

苝四甲酸二酐有机单晶纳米结构的制备及形成机理的研究

在分子束外延(MBE)系统中, 利用物理气相沉积(PVD)的方法在阳极氧化铝(AAO)模板上制备了有机 染料分子苝四甲酸二酐(PTCDA)的不同纳米结构; 并使用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、 高分辨透射电子显微镜(HRTEM)以及选区电子衍射(SAED)技术进行了系统的研究. 结果发现, 当衬底温度(T_s)为330 ℃时得到的是纳米丝、针、带以及棒; T_s为280 ℃, 230 ℃, 180 ℃时得到的主要是纳米棒, 并且纳米棒的长度随T_s的降低而变短; T_s为50 ℃时只能得到连续的PTCDA薄膜. HRTEM以及SAED结果证实了纳米针与棒为单晶. 依据SEM结果, 提出纳米结构的生成主要受T_s以及衬底表面曲率的影响.