A Critical Examination to the Unitarized IJ ＝ 20 ππ Scattering Chiral Amplitude

We discuss the Padé approximation to the ππ scattering amplitudes in one-loop chiral perturbation theory.The approximation restores unitarity and can reproduce the correct resonance poles,but the approximation violates crossing symmetry and produces spurious poles on the complex s plane and therefore plagues its predictions in some cases.However we find that one virtual state in the IJ = 20 channel may have physical relevance.     

宽带接入技术

本文介绍了包括xDSL、Cable Modem、APON、宽带有源光网络和HFC等几种典型的有线宽带接入技术,分析了各宽带接入技术的特点及存在的问题,并针对目前正在推广发展的ADSL技术,分析了影响ADSL传输性能与速率的各种因素。     

激光促进甲醇在氧化物上的表面反应

运用红外光谱（IR）、程序升温脱附（TPD）技术,对甲醇吸附在氧化物SiO2、γ－Al2O3和MgO表面所形成的反应体系进行了红外振动结构和化学吸附形态分析,并引入1052cm^-1激光,研究了上述体系的激光促进表面反应（LSSR）规律。结果表明：所选固体材料能够明显促进甲醇光促分解反应,室温条件下即可在SiO2上达到40.5%的转化率;另外与甲醇吸附强度和吸附量相比,反应体系的振动结构对LSSR效率起着更为重要的作用,SiO2因能够较好地吸收、传送激光能量而具有比γ－Al2O3和MgO更好的促进反应性能。最后,根据表征和反应结果给出了反应机理的模型。     

Bismuth Mediated Organic Reaction: A Convenient Method for the Synthesis of Allylic (Benzylic) Selenides and α-Organylselenocarbonyl Compounds in Aqueous Media

Organic reactions promoted by active metals have aroused much interest in recent years. Active bismuth has been used in Barbier-type reaction of allylic halides with aldehydes1 and aldimines2 as well as Reformatzky type reaction3. Other publications referred to the cross coupling between aldehydes and α-diketones4, the substitution to benzotriazole drivatives5 and the reductive coupling reaction of nitro compounds6. These reactions generally promoted by elemental bismuth generated in situ fr…     

A Dye-sensitized Nanocrystalline Solid State Photovoltaic Cell

Dye-sensitized photovoltaic cells based on nanocrystalline TiO, film are of considerabletechnological interest because of their high conversion efficiency and potential low cost.However the liquid junction photovoltaic cells have a series of technological problems inpractical applications. Recently, the replacement of liquid electrolyte by solid stateconductors such as ionic conducting polymers' and organic hole tfansport materialsZ hasbeen tested. In this papef, we report the fabrication of …     

加快小城镇建设促新疆经济增长

分析了小城镇建设的现实,指出在新疆,以促进小城镇建设作为经济发展的重要推动力,可缓解城市对立的二元经济结构,经济要素分散及刺激内需的问题,也可实现农村剩余劳动力的转移,增加农民的收入和农业化经营,因地制宜,选择性地进行小城镇建设,在科学规划的基础上,实现南北疆的协调发展,可持续增长。     

改进溶胶-凝胶法固定酶结构剖析及在苯酚光化学传感器中的应用

通过光学显微镜比较了用密闭老化法和浸涂法制备的溶胶凝胶膜的表面状态,从实验上证实了用密闭老化法制备的溶胶凝胶膜不会破裂;并用透射电子显微镜观察了包埋辣根过氧化物酶的溶胶凝胶膜的内部结构.结果表明,酶固定于溶胶凝胶中后,与在溶液中一样,呈均匀分布且不易流失.此敏感膜可用于制备基于化学发光强度减弱的苯酚光化学传感器;用竞争反应的原理讨论了响应机理.     

A Ferritin Reactor for Entrapping Various Heavy Metal Ions in Flowing Seawater

Recent studies showed that the ferritins had three tunnels across the protein shell with 0.7~0.9 nm diameter for iron metabolism^[1-2]. However, very little was known the mechanism(s) that the ferritin reactor entrapped various heavy metal ions (M²⁺) and other small organic molecules in the flowing seawater directly.     

应用ABEEM模型计算铁(Ⅱ)配合物的电荷分布

以密度泛函理论和电负性均衡原理为基础,在原子-键电负性均衡模型中,利用最小二乘法,并结合自编程序,拟合确定了氢、碳、氮、硫以及铁(Ⅱ)等各种类型的原子及相关化学键区域的参数.利用上述参数计算了一些铁(Ⅱ)配合物的电荷分布,计算结果可以和从头算结果很好地相关联.     

A Secondary Operator Ordering Problem for a Charged Rigid PlanarRotator in Uniform Magnetic Field

When the motion of a particle is constrained, an excess term exists using hermitian form of Cartesian momentum pi(i= 1, 2, 3) in usual kinetic energy (1/2μ)∑Pi^2, and the correct kinetic energy turns out to be (1/2μ)∑(1/fi)pifipi, where the fi are dummy factors in classical mechanics and nontrivial in quantum mechanics. In this paper the explicit form of the dummy functions f i is given for a charged rigid planar rotator in the uniform magnetic fieM.