TE011腔使用扁平样品管提高水溶液样品ESR波谱灵敏度的研究

实验表明,在TE₀₁₁模式园柱形腔中,不但可以使用扁平样品管测量水溶液样品的ESR波谱,而且获得好的腔品质因子Q和高品质的ESR信号。所观察到的信号高度,是使用最佳尺寸毛细管样品时最大信号高度的3.2倍;又是在具有波导尺寸的TE₁₀₂腔中使用扁平样品管时所获得信号高度的3倍。本文对此作了定性的理论分析。     

A Fourier spectral-discontinuous Galerkin method for time-dependent 3-D Schrödinger–Poisson equations with discontinuous potentials

In this paper, we propose a high order Fourier spectral-discontinuous Galerkin method for time-dependent Schrödinger–Poisson equations in 3-D spaces. The Fourier spectral Galerkin method is used for the two periodic transverse directions and a high order discontinuous Galerkin method for the longitudinal propagation direction. Such a combination results in a diagonal form for the differential operators along the transverse directions and a flexible method to handle the discontinuous potentials present in quantum heterojunction and supperlattice structures. As the derivative matrices are required for various time integration schemes such as the exponential time differencing and Crank Nicholson methods, explicit derivative matrices of the discontinuous Galerkin method of various orders are derived. Numerical results, using the proposed method with various time integration schemes, are provided to validate the method.     

Synthesis and characterization of well‐defined polystyrene and poly(ε‐caprolactone) hetero eight‐shaped copolymers

Well‐defined hetero eight‐shaped copolymers composed of polystyrene (PS) and poly(ε‐caprolactone) (PCL) with controlled molecular weight and narrow molecular weight distribution were successfully synthesized by the combination of ring‐opening polymerization, ATRP, and “click” reaction. The synthetic procedure involves three steps: (1) preparation of a tetrafunctional PS and PCL star copolymer with two PS and two PCL arms using the tetrafunctional initiator bearing two hydroxyl groups and two bromo groups; (2) synthesis of tetrafunctional star copolymer, (α‐acetylene‐PCL)₂(ω‐azido‐PS)₂, by the transition of terminal hydroxyl and bromo groups to acetylene and azido groups through the reaction with 4‐propargyloxybutanedioyl chloride and NaN₃ respectively; (3) intramolecular cyclization reaction to produce the hetero eight‐shaped copolymers using “click” chemistry under high dilution. The ¹H NMR, FTIR, and gel permeation chromatography techniques were applied to characterize the chemical structures of the resulted intermediates and the target polymers. Their thermal behavior was investigated by DSC, and their crystallization behaviors of PCL were studied by polarized optical microscopy. The decrease in chain mobility of the eight‐shaped copolymers restricts the crystallization of PCL and the crystallization rate of PCL is slower in comparison with their corresponding star precursors. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6496–6508, 2008     

(农药-纤维素)酯类缓释剂的合成及水解性能的研究

以纤维素和羧甲基纤维素作为载体,将带有羧基的2,4-二氯苯氧乙酸和带有羟基的五氯酚等农药分别与它们相结合。制备了分子链上键合有农药的高聚物。进而通过水解试验其释放农药的性能。结果表明:农药在纤维素链上的替代度可以通过控制反应条件加以调节,所制备的键合有农药的高聚物可以自行水解而缓慢地释放出农药,并随水解时间的延长,释放速度逐渐减慢。     

水平连铸圆坯非金属夹杂物的研究

钢中非金属夹杂物对产品质量有重要影响。本文调查了水平连铸圆坯夹物形态、组成和分布,并对铸坯中夹杂物来源做了初步分析。     

煤基腐植酸对久效磷的增效作用研究

水溶性煤基酸分为从含有水溶性煤基酸的低价煤中抽提得到的水溶性煤基酸和从不含有水溶性煤基酸的低阶煤中氧化得到的水溶性煤基酸。考察了从武川风化煤和霍林河风化褐煤通过两步催化氧化法得到的水溶性煤基酸和从晋城风化煤中得到的水溶性煤基酸对高效、高毒性的杀虫剂--久效磷生物活性的影响。结果表明：（1）三种煤基酸都能增加久效磷的生物活性；（2）所用水溶性煤基酸的理想浓度为0.0025％；（3）根据毒力曲线，久效磷、武川煤基酸-久效磷和霍林河-久效磷的致死中浓度为9.94g/ha，5.99g/ha，6.62g/ha，相对毒力系数分别为：100，165.9，150.2；（4）大田实验结果证实了水溶性煤基酸对久效磷的增效作用。     

KNOT STRENGTH OF INDUSTRIAL TEXTILE FIBRES

In this paper, the knot strengths of the seven strands which were made of polyethleneterephthalate(PET), nylon 6, polyvinyl formal fibre, polypropylene and polyethylene with differentspecification used for industrial purposes were tested and discussed. The results of experimentshow: the knot strength loss does not only depend on the breaking elongation and the diameter ofsample, but also on the shape of the load-extension curve and twist factor of sample and other fac-tors; the range of the knot strength loss and the breaking energy loss vary in a wide range, in thepresent case. the former is from 2.7% to 58.14% and the latter from 16.36% to 78.76%. Thestrength loss of the polypropylene filament is the least among the samples investigated.     

统计热力学偶势超稳定性证明

对连续态的正则偶势证明其满足超稳定条件，其方法是在束缚态间嵌入一满足Ｒｕｅｌｅ判据的函数，并选择最简洁的形状因子，筛选确定最佳参数，使其既能获得非理想玻色气体的每一质点高密度基态能极限，又有最理想常数，这在统计热力学领域具有较好的应用前景。     

DNA-modified electrodes (VII)

Two kinds of DNA-modified electrodes were prepared by covalent and adsorptive immobilization of DNA onto self-assembled monolayers of 2, 2’-dithiodiethanol on gold electrodes and characterized by cyclic voltammetry, X-ray photoelectron spectroscopy and scanning tunneling microscopy. The results suggest that the methods are satisfactory for the immobilization of DNA on electrodes. Project supported by the National Natural Science Foundation of China (Grant Nos. 39370213; 39770220; 29773034), State Key Laboratory for Physical Chemistry of Solid Surfaces (Xiamen University), and Natural Science Foundation of Hubei Province (Grant NO. 96J037).