浙江中部夏熟作物田主要杂草生态相似性的数量分析

应用七级目测法对浙江中部地区27个夏熟作物田样点的杂草进行了优势等级调查，将所得数据转换成重要值，以杂草在27个样点中的重要值为运算指标，应用主成分分析法和图论聚类中的最小生成树法，对24种杂草的生态学相似性进行了比较，指出了长期使用单一的除草剂导致农田杂草种群迅速更迭的原因：杂草对除草剂的敏感性差异及不同杂草间的生态学特性的差异。     

Effect of the Electron-LO-Phonon Coupling on an Exciton Quantum Dot

The influence of the electron-LO-phonon coupling on energy spectrum of the low-lying states ofan exciton inparabolic quantum dots is investigated as a function of dot size. Calculations are made by using the method of few-bodyphysics within the effective-mass approximation. A considerable decrease of the energy in the stronger confinement rangeis found for the low-lying states of an exciton in quantum dots, which results from the confinement of electron-phononcoupling.     

Interface Optical Phonon Modes and Frohlich Electron-Phonon Interaction Hamiltonian in a Multi-shell Spherical Nanoheterosystem

Under dielectric continuum approximation, interface optical (IO) phonon modes and the Frohlich electron-IO phonon interaction Hamiltonian in a multi-shell spherical nanoheterosystem were derived and studied. Numericalcalculations on three-layer and four-layer CdS/HgS spherical nanoheterosystems have been performed. Results revealthat there are four IO phonon modes for the three-layer system and six IO phonon modes for the four-layer system.On each interface, there are two IO phonon modes, the frequency of one is between WTO,CdS and WLO,CdS, and that ofthe other is between WTO,HgS and WLO,HgS. With the increasing of quantum number l, the frequency of each IO modeapproaches one of the two frequency values of the single CdS/HgS heterostructure, and the potential for each IO modeis more and more localized at a certain interface, furthermore, the coupling between the electron-lO phonons becomes weaker.     

ICP-AES测定钛基复合材料中镍、钕和铁的研究

采用ICP－AES法对钛基复合材料中的合金元素镍、钕、铁的测定进行了研究，着重进行了基体元素及待测元素镍、钕、铁之间干扰试验及各元素在测定浓度范围内的线性相关性试验，进行了酸度试验，测定了钛基复合材料中3种元素的含量，得到了较好的精密度和准确度。方法简便、可靠，获得满意的分析结果。     

藻类植物中钙、镁、铁、锰、铜和锌含量分析

本文采用火焰原子吸收光谱法测定了七种藻类植物中钙 ,镁 ,铁 ,锰 ,铜 ,锌六种元素的含量。结果表明 ,藻类植物中含有较丰富的钙 ,镁 ,铁 ,锰 ,锌元素 ,其含量由大到小顺序为Ca >Mg >Fe >Zn >Mn >Cu ,尤以钙的含量最为丰富 ,铜含量较少。本实验结果为探讨藻类植物作为资源开发利用提供了有用数据。     

针对混合应用业务的ARQ改进方案

在高速无线通信中,自动请求重传(ARQ)是链路层不可缺少的技术,它通过重传向上层屏蔽无线链路上包的丢失。随着无线网络的发展,无线传输速率不断提高,应用的业务类型也越来越广泛。目前,众多ARQ技术的研究都集中在如何提高该技术的确认效率,以适应更高的传输速率,但鲜有研究着手于如何使ARQ能够更好地应用于混合业务环境。针对混合业务环境下的ARQ改进提出了2种方案,并给出其中1种在实际应用中的改善效果。     

绿色荧光粉YAGG∶Tb,Gd用于FED的尝试

FED器件的发展迫切需要具有化学和热稳定性 ,高亮度 ,长寿命的新型荧光材料。本文合成了Gd3 +离子共掺杂的YAGG∶Tb获得了YAGG∶Tb ,Gd ,并将其用于 0～ 30 0 0V低压范围 ,对其在不同电压和电流密度下的发光特性进行了测试。结果表明 ,该种材料特性优于ZnO∶Zn并且不存在电压与电流饱和     

Existence of solutions for the time-dependent thermistor equations

The equations describing the behaviour of temperature/flow microsensorsemploy-ing polysilicon thermistors form a degenerate nonlinearparabolic system. One special feature is that different equationsof this system are to be satisfied on different domains. Bymeans of supersolutions and subsolutions, the maximum principle,and fixed point arguments, the authors show the existence ofsolutions to the equations.     

含氢硅单晶2210cm-1红外吸收峰本质的理论研究——Ⅰ.振子频率的价键力场计算

本文根据Urey-Bradely 力场的思想,用价键力场的方法对文献[1]中提出的含氢硅单晶中2210cm^-1吸收峰对应的缺陷复合体的两个模型:空位+4H,间隙硅烷,进行了振动频率的计算.在对计算结果和力常数调节合理性分析的基础上,得出了空位+4H模型比较合理的结论.此外还介绍了理论计算揭示的从实验上区分两个模型的可靠途径.     

Bistable Behaviour of N Two-Level Atoms Interacting with the Field inside a High-Q Cavity Containing a Nonlinear Kerr-Like Medium

Taking the intensity-dependent coupling between atoms and cavity mode into account, we investigate a system consisting of N homogeneously broadened two-level atoms interacting with the field inside a single-mode Fabry- Perot cavity containing a nonlinear Kerr-like medium. We derive the steady-state bistable behaviour of the system, and further analyse in details the influence of several critical parameters on the bistable behaviour.