New Power Lateral Double Diffused Metal-Oxide-Semiconductor Transistor with a Folded Accumulation Layer

A new lateral double diffused metal oxide semiconductor field effect transistor with a double-charge accumulation layer using a folded silicon substrate is proposed to improve the performance of the breakdown voltage and specific on-resistance. Three kinds of technologies, which are the additional electric field modulation effect, majority carrier accumulation and increasing the effective conduction area, are applied simultaneously by a semi- insulating polycrystalline silicon layer deposited over the top of thin oxide covering the drift region. It is indicated that by the simulator, the ideal silicon limits of the breakdown voltage and specific on-resistance have been broken due to the complete three-dimensional reduced surface field effect and the doubled majority carrier accumulation layer.     

Analysis of space harmonic selectivity of period-varying folded waveguide

A period-varying folded waveguide is formed by varying the period of a folded waveguide. It has the advantages of the space harmonic selectivity and the wide bandwidth. However, the regularities of the variety of these period-varying folded waveguides are unavailable from the published papers. In order to solve this problem, the principle of the space harmonic selectivity of a period-varying folded waveguide is analysed, and the conditions to select the space harmonic for this slow wave system are obtained. In addition, the space harmonic selectivities for a linear period-varying folded waveguide and a hyperbolic sine-varying period folded waveguide are also analysed as examples.     

Return maps of folded nodes and folded saddle-nodes

Folded nodes occur in generic slow-fast dynamical systems with two slow variables. Open regions of initial conditions flow into a folded node in an open set of such systems, so folded nodes are an important feature of generic slow-fast systems. Twisting and linking of trajectories in the vicinity of a folded node have been studied previously, but their consequences for global dynamical behavior have hardly been investigated. One manifestation of the twisting is as "mixed mode oscillations" observed in chemical and neural systems. This paper presents the first systematic numerical study of return maps for trajectories that flow through a region with a folded node. These return maps are approximated by rank-1 maps, and the local twisting of trajectories near a folded node gives rise to multiple turning points in the approximating one dimensional maps. A variant of the forced van der Pol system is used here to illustrate that folded nodes can be a "chaos-generating" mechanism. Folded saddle-nodes occur in generic one-parameter families of slow-fast dynamical systems with two slow variables. These bifurcations give birth to folded nodes. Numerical simulations demonstrate that return maps of systems that are close to a folded saddle-node can be even more complex than those of folded nodes that are far from folded saddles.     

Ka波段曲折双脊波导行波管的研究

提出了一种曲折双脊波导慢波结构,理论分析了慢波结构的高频特性,并在此基础上设计了工作在Ka波段的曲折双脊波导行波管.利用三维粒子模拟软件MAGIC 3D建立了曲折双脊波导行波管模型,并对行波管中的注-波互作用进行了模拟分析.在相同工作条件下,分析比较了曲折双脊波导行波管和曲折波导行波管的各种性能参量,从中发现：在行波管增益峰值相近的情况下,曲折双脊波导行波管具有更好的带宽性能,其3 dB增益带宽为22％;同时具有更高的电子效率,其峰值接近9％. 关键词： 曲折双脊波导 高频特性 注-波互作用 带宽     

Periodic Folded Wave Patterns for (2+1)-Dimensional Higher-Order Broer-Kaup Equation

A general solution including three arbitrary functions is obtained for the (2+1)-dimensional higher-order Broer-Kaup equation by means of WTC truncation method. Introducing proper multiple valued functions and Jacobi elliptic functions in the seed solution, special types of periodic folded waves are derived. In long wave limit these periodic folded wave patterns may degenerate into single localized folded solitary wave excitations. The interactions of the periodic folded waves and their degenerated single folded solitary waves are investigated graphically and are found to be completely elastic.     

Periodic folded waves for a （2＋1）-dimensional modified dispersive water wave equation

A general solution, including three arbitrary functions, is obtained for a (2+1)-dimensional modified dispersive water-wave (MDWW) equation by means of the WTC truncation method. Introducing proper multiple valued functions and Jacobi elliptic functions in the seed solution, special types of periodic folded waves are derived. In the long wave limit these periodic folded wave patterns may degenerate into single localized folded solitary wave excitations. The interactions of the periodic folded waves and the degenerated single folded solitary waves are investigated graphically and found to be completely elastic.     

Folded Solitary Waves and Foldons in （2＋1） Dimensions

A general type of local/zed excitations, folded solitary waves and foldons, is defined and studied both analytically and graphically. The folded solitary waves and foldons may be “folded“ in quite complicated ways and possess qnite rich structures and abundant interaction properties. The folded phenomenon is quite universal in the real natural world. The folded solitary waves and foldons are obtained from a quite universal formula and the universal formul is valid for some quite universal (2 1)-dimensional physical mode/s. The “universal“ formula is also extended to a more general form with many more independent arbitrary functions.     

Potts-Ising model for simulation of polarization switching in polycrystalline ferroelectrics

This paper proposes a scheme based on the Potts and Ising models for simulating polarization switching of polycrystalline ferroelectrics using the Monte Carlo method. The polycrystalline texture with different average grain size is produced from the Potts model. Then Ising model is implemented in the polycrystalline texture to produce the domain pattern and hysteresis loop. The domain patterns and hysteresis loops have been obtained for polycrystalline texture with different average grain size. From the results of domain pattern evolution process under an applied electric field using this scheme, an extended domain, which covers more than one grain with polarization aligned roughly in the same direction, has been observed during the polarization reversal. This scheme can well reproduce the basic properties of polycrystalline ferroelectrics and is a valuable tool for exploring the physical properties of polycrystalline ferroelectrics.     

Folded Solitary Waves and Foldons in(2+1) Dimensions

A general type of localized excitations, folded solitary waves and foldons, is defined and studied bothanalytically and graphically. The folded solitary waves and foldons may be “folded“ in quite complicated ways andpossess quite rich structures and abundant interaction properties. The folded phenomenon is quite universal in the realnatural world. The folded solitary waves and foldons are obtained from a quite universal formula and the universalformula is valid for some quite universal (2 1)-dimensional physical models. The “universal“ formula is also extendedto a more general form with many more independent arbitrary functions.     

Effective three-nucleon forces from the folded diagram expansion

The folded diagram expansion for the effective hamiltonian of a system of three valence nucleons in the 1s0d shell is investigated. Beside the one-body and two-body operators, which already occur in the folded diagram expansion for systems with one and two valence nucleons, also folded diagrams involving three nucleons are obtained. These terms, which can be interpreted as a contribution to an effective three-nucleon force, yield a non-negligible contribution which is repulsive for the low-lying states. Two different techniques are studied for the summation of the folded diagrams. A very good convergence is obtained using the Lee-Suzuki iteration scheme.     

Modeling of polycrystalline ZnO thin-film transistors with a consideration of the deep and tail states

We report a model of the carrier transport and the subgap density of states in a polycrystalline ZnO film for simulating a polycrystalline ZnO thin film transistor. This simple model considering the deep and the band tail states reproduces well the characteristics of polycrystalline ZnO thin film transistors. Furthermore, using the developed model, we study the effects of defect parameters on the electrical performances of the polycrystalline ZnO thin film transistors.     

山东蒙阴金刚石多晶的显微红外光谱研究及其成因意义

山东蒙阴金刚石多晶可划分为多角刻面状和浑圆状金刚石多晶两大类,它们的显微红外光谱研究结果表明,金刚石多晶中的氮含量较低,介于16.69～72.81μg.g-1之间,且同一金刚石多晶的不同金刚石晶粒(或部位)中的氮含量不相同;刻面状金刚石多晶均为ⅠaAB型,且A心的浓度大于B心的浓度。浑圆状金刚石多晶也多为ⅠaAB型,但具有更高浓度的B心,且存在少数同时包含单替代氮、A心和B心的浑圆状金刚石多晶;金刚石多晶不是在金刚石颗粒的成核阶段所形成的,而是在金刚石长大期间或金刚石颗粒形成后的某个特殊条件下聚集而成;山东蒙阴金刚石多晶可能形成于氮浓度较低的较深部地幔。同时,多角刻面状金刚石多晶的形成时间稍晚于金刚石单晶体,浑圆状金刚石多晶的形成时间明显早于金刚石单晶体。     

Many-body terms in the folded diagram expansion

The folded diagram expansion for the effective hamiltonian to be used in shell-model calculations for a system with A valence nucleons yields folded diagrams connecting up to A nucleons. The importance of such effective many-nucleon forces is investigated for the example of 4 valence nucleons in the 1s0d shell (²⁰Ne). The folded diagram terms turn out to reduce the binding energy for the low-lying states. The effects of the folded diagrams involving three nucleons are of the same importance as those of the two-body terms. The four-nucleon forces originating from folded diagrams are considerably weaker. This suggests that three-body operators have to be considered in a microscopic calculation of an effective energy-independent shell-model hamiltonian, whereas terms involving four nucleons may be ignored.     

The study of synchronization in the periodic nonuniform folded waveguide

The periodic nonuniform folded waveguides are special structures, the physical dimension of which is between the periodic folded waveguide and the tapering period folded waveguide. Therefore, the synchronization between the microwave and the electron beam can be maintained in the whole interaction process and the periods are not tapered. In comparison with the tapering period folded waveguide, the theoretical analysis and the technological requirements for this structure are more convenient. In order to study this structure, the space harmonics are analysed, the conditions to make the m-th space harmonic synchronizing with the electron beam in the whole interaction process are present, and the dispersion curve and the coupling impedance curve are obtained by the simulation software HFSS.     

A study of kinetic effects in isotropic polycrystalline <Emphasis Type="Italic">p</Emphasis>-type silicon

A formula is derived for calculating the relaxation time of charge carriers scattered both by a disordered atomic lattice of polycrystalline silicon and by a system of disordered potential barriers formed on the surfaces of crystallites in isotropic polycrystalline silicon. The hole relaxation time is analyzed, and the temperature dependence of hole mobility is calculated for the p-type polycrystalline silicon. The calculations of the Hall factor, differential thermal emf, transverse magnetoresistance, and coefficients of elastoconductivity due to hole scattering by the disordered atomic lattice and by the potential barriers formed on the crystallite surfaces in isotropic polycrystalline p-type silicon are also made. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 76–88, February, 2008.     

结构参数对折叠波导行波管工作性能的影响

分析和计算了互作用区折叠波导截面长宽比(b/a)、直边高度和电子束通道大小等结构参数对太赫兹波段折叠波导行波管工作性能的影响。结果表明:互作用区衰减常数随b/a的增大而减小, 耦合阻抗和小信号增益则随b/a的增大先增加而后减小, 存在最优值。电子束通道越大, 衰减常数越大, 耦合阻抗和小信号增益降低得越多。相对于电子束通道, 增益和损耗对直边高度的敏感程度显著降低。因此为了提高器件功率容量, 可适当增加折叠波导的高度;在保证电子束能够顺利传输的前提下, 电子束通道越小越好。在折叠波导行波管的实际研制中, 可依据具体的实验条件和要求, 在适当的范围内合理选取互作用区各结构参数的值。     

结构参数对折叠波导行波管工作性能的影响

分析和计算了互作用区折叠波导截面长宽比(b/a)、直边高度和电子束通道大小等结构参数对太赫兹波段折叠波导行波管工作性能的影响。结果表明：互作用区衰减常数随b/a的增大而减小, 耦合阻抗和小信号增益则随b/a的增大先增加而后减小, 存在最优值。电子束通道越大, 衰减常数越大, 耦合阻抗和小信号增益降低得越多。相对于电子束通道, 增益和损耗对直边高度的敏感程度显著降低。因此为了提高器件功率容量, 可适当增加折叠波导的高度;在保证电子束能够顺利传输的前提下, 电子束通道越小越好。在折叠波导行波管的实际研制中, 可依据具体的实验条件和要求, 在适当的范围内合理选取互作用区各结构参数的值。     

LD抽运的折叠腔Nd∶YVO4/KTP倍频红光激光器

对LD端面抽运的Nd∶YVO₄/KTP腔内倍频激光器的三镜折叠腔结构进行优化设计,研究了总腔长、输入镜曲率半径和Nd∶YVO₄和KTP晶体的热效应对激光谐振腔的稳定区域、Nd∶YVO₄晶体内基模光束半径的影响。实验结果表明:该方法所得出的结论与理论相吻合。在实验中比较了折叠腔不同折叠角度的红光输出功率,并获得了最佳折叠角度为25°,其有效倍频效率为10.8%。最后使用基频光的偏振特性与KTP的相位匹配之间的关系对实验结果进行理论解释。     

Characterization Method of Polycrystalline Materials Using Conductive Atomic Force Microscopy

An apparatus for characterization of polycrystalline materials based on conductive atomic torce microscopy （cAFM） is developed and a quantitative measurement of electrical characteristics of individual grains in polycrystalline ZnO ceramic is demonstrated. Improvement of the experimental method is presented. Experimental results illuminate unambiguously the different electrical characteristics between individual grains, suggesting the suitability and maneuverability of this method in the study of local structure or properties and their relationship in polycrystalline materials such as semi-conducting ceramics.     

毫米波折叠波导行波管输入输出过渡波导设计

折叠波导以其宽频带、加工方便而成为一类重要的毫米波与太赫兹波段行波管慢波线。针对折叠波导慢波系统与标准波导的匹配过渡连接,通过等效电路分析与电磁计算软件模拟,设计出了直渐变波导、双曲圆弧渐变波导、切比雪夫阶梯渐变波导3种输入输出过渡波导结构,分析了各种过渡波导的优缺点及结构尺寸对性能的影响。计算表明,经过合理优化的设计,3种过渡结构均可以使反射系数在28~40 GHz波段小于0.05。