非线性离散微分方程的双曲函数法求解

本文推广了双曲函数方法用于求解非线性离散系统。求解离散的(2+1)维Toda系统和离散的mKdV系统，成功地得到了离散钟型孤立子、离散冲击波型孤立子及一些新的精确行波解。     

Concentric-ring structures in an atmospheric pressure helium dielectric barrier discharge

This paper performs a numerical simulation of concentric-ring discharge structures within the scope of a two-dimensional diffusion--drift model at atmospheric pressure between two parallel circular electrodes covered with thin dielectric layers. With a relative high frequency the discharge structures present different appearances of ring structures within different radii in time due to the evolvement of the filaments. The spontaneous electron density distributions help understanding the formation and development of self-organized discharge structures. During a cycle the electron avalanches are triggered by the electric field strengthened by the feeding voltage and the residual charged particles on the barrier surface deposited in the previous discharges. The accumulation of charges is shown to play a dominant role in the generation and annihilation of the discharge structures. Besides, the rings split and unify to bring and annihilate rings which form a new discharge structure.     

Analysis of Ar line spectra from indirectly-driven implosion experiments on SGII facility

This paper reports on the indirectly-driven implosion experiments on SGII laser facility in which Ar emission spectrum from Ar-doped D-filled plastic capsule is recorded with the crystal spectrometer. Spectral features of Ar Heβ line and its associated satellites are analysed to extract the electron temperature and density of the implosion core. Non local thermal equilibrium (NLTE) collisional-radiative atomic kinetics and Strark broadening line shape are included in the present calculation. By comparing the calculated spectrum with the measured one, the core electron temperature and density are inferred to be 700 eV and 2.5×10²³ cm^-3 respectively. With these inferred values of electron temperature and density, neutron yield can be estimated to agree with the measured value in magnitude despite of the very simple model used for the estimation.     

A general mapping approach and new travelling wave solutions to the general variable coefficient KdV equation

A general mapping deformation method is applied to a generalized variable coefficient KdV equation. Many new types of exact solutions, including solitary wave solutions, periodic wave solutions, Jacobian and Weierstrass doubly periodic wave solutions and other exact excitations are obtained by the use of a simple algebraic transformation relation between the generalized variable coefficient KdV equation and a generalized cubic nonlinear Klein－Gordon equation.     

类铍铝离子的Kα跃迁特性研究

我们报道了类Be的Al X最低40个能级的能级精细结构.利用基于多组态Dirac-Fock方程,我们给出了类Be的Al X的K_α跃迁的能级,波长,振子强度和能级寿命.研究表明,当前所得的理论计算结果与实验值以及其它理论值符合很好,同时对于分析已有的实验结果和指导拟开展的实验也有一定的意义.     

K-Shell Spectra from CH-Tamped Aluminum Layers Irradiated with Intense Femtosecond Laser Pulses

X-ray spectra of H-like and He-like aluminum ions from aluminum buried in CH layers irradiated with 30fs, 200 TW laser are measured. The electron temperature and density are derived from line ratios of the He-α resonance line to its satellite lines. Typical temperatures of 490-646 eV and electron densities up to 7 × 10^20 cm-3 are obtained. The results show that the electron density increases and temperature decreases with the increasing CH thickness.     

Robust Output Tracking Control of an Uncertain Linear System via a Modified Optimal Linear-Quadratic Method

This study investigates the robust output tracking problem for a class of uncertain linear systems. The uncertainties are assumed to be time invariant and to satisfy the matching conditions. According to the selected nominal parameters, an optimal solution with a prescribed degree of stability is determined. Then, an auxiliary input via the use of an adapting factor, connected to the nominal optimal control, is introduced to guarantee the robustness and prescribed degree of stability for the output tracking control of the uncertain linear systems. This method is very simple and effective and can reject bounded uncertainties imposed on the states. A maglev vehicle model example is given to show its effectiveness.     

Passive coupling of InGaAsP/InP laser array and singlemode fibres using silicon waferboard

Passive alignment of semiconductor lasers and singlemode fibres has been achieved for the first time using a micro-machined silicon substrate. Mechanical alignment features fabricated on the substrate surface were used to align the active regions of an InGaAsP/InP laser array to four singlemode fibres held in V grooves. Optical coupling efficiencies have been achieved that are comparable to values obtained using the conventional technique of active fibre manipulation. The approach, called silicon waferboard, offers the potential for low-cost optoelectronic device packaging as well as a means for dense hybrid integration of optoelectronic, electronic and optical components required for multifibre, multichip systems.<>     

Secure encrypted-data aggregation for wireless sensor networks

This paper proposes a secure encrypted-data aggregation scheme for wireless sensor networks. Our design for data aggregation eliminates redundant sensor readings without using encryption and maintains data secrecy and privacy during transmission. Conventional aggregation functions operate when readings are received in plaintext. If readings are encrypted, aggregation requires decryption creating extra overhead and key management issues. In contrast to conventional schemes, our proposed scheme provides security and privacy, and duplicate instances of original readings will be aggregated into a single packet. Our scheme is resilient to known-plaintext attacks, chosen-plaintext attacks, ciphertext-only attacks and man-in-the-middle attacks. Our experiments show that our proposed aggregation method significantly reduces communication overhead and can be practically implemented in on-the-shelf sensor platforms.     

The dual-edge alignment technique with improved spur reduction effects in ring oscillators

In this paper, the technique of dual-edge phase-alignment and its effects on ring oscillators are presented. This technique provides resetting of the built-up jitter at both rising and falling edges of a clean aligning signal named as the reference. Using signals and systems theory, the effect of the technique on the spurs due to the aligning reference signal is completely analyzed. We show that adding properly the dual-edge aligning feature to phase-aligned ring oscillators cause the spurs in the neighborhood of the carrier to disappear. First, the validity of the results obtained from the derived analytical equations is verified through simulations using MATLAB. Then a complete circuit considering realistic models for its components is simulated in TSMC RF CMOS 0.18um process using ADS for further validation.