冷链物流监控系统设计

系统针对冷链物流需求设计,包括终端设备与服务器。终端设备采用单片机低功耗、传感器、远程无线监控、数据管理与压缩、GPRS基站定位技术,使得终端设备能够良好地服务于冷链物流。服务器采用B/S服务器网络技术,用户可以登陆网页配置终端设备工作参数,并可以查看终端设备过程状态。系统在冷链物流的实际应用过程中,表现出良好的实际应用价值,对冷链监控有一定的意义,在市场中具有广泛的发展前景。     

降低TDCS峰均功率比算法及性能分析

针对变换域通信系统出现的高峰均功率比的问题,提出了一种降低TDCS系统峰均功率比的算法。该算法通过对随机相位进行选择,生成一定数量的基函数,并在此基础上,寻找到峰均功率比较低的基函数来传输数据,从而得到改进的TDCS框图。仿真结果表明,改进算法能在不影响TDCS的误码率性能的情况下有效降低PAPR,在CCDF为10-3时,改进算法的PA0较原始TDCS降低了6.1 dB。     

A new generalization of Hardy–Berndt sums

In this paper, we construct a new generalization of Hardy–Berndt sums which are explicit extensions of Hardy–Berndt sums. We express these sums in terms of Dedekind sums s _r (h, k : x, y|λ) with x?=?y?=?0 and obtain corresponding reciprocity formulas.     

Low Frequency Ultra-Thin Compact Metamaterial Absorber Comprising Split-Ring Resonators

We present a design of a low frequency ultra-thin compact and polarization-insensitive metamaterial absorber （MA）. The designed MA is a two-layer structure, a periodic array of novel split-ring resonators （SRRs）, which are constructed in an FR4 dielectric layer, and another ultra-thin grounded sheet is attached to the bottom. Numerical simulated results show that the proposed MA can realize effective absorption at the frequency 281.9 MHz, and its overall thickness is just only 0.29% of the resonant wavelength, the unit space is only 2.57%, and the absorbanee is kept well for a wide range of incident angles for different polarizations. In addition, the proposed MA is changed into a more compact one when the inter-digital structures are introduced in the SRRs. One convenient experiment is carried out in a rectangular waveguide simulator.     

A cDNA CLONE WITH ANTIONCOGENE ACTIVITY

A cDNA clone, p14--6, which has an antioncogene activity on the v--Ki--Ras oncogene-transformed malignant cell line DT, was found. This clone was recovered from the revertantR14 cells, which had been isolated by transfections of DT cells with a normal human fibro-blast cDNA library cloned in pcD2, an Okayama-Berg vector. When transfected into DT cells,p14--6 clone gave rise to phenotypical flat reversion in 5--15% of DT transfectant colo-nies. The p14--6--transfected flat cell line, RR, was proven to be a true revertant with signif-icantly reduced malignancy by in ritro and in riro malignancy tests. All other clones recov-ered from R14 cells were unable to cause this reversion. Molecular hybridizations showedthat the p14--6 was inserted into RR genome as tandem repeats, and no structural changewas found in the D--Ki--Ras oncogene in RR genome. These facts suggest that the antioncogeneactivity of the p14--6 clone on the DT cells may be exerted through expression of thecDNA contained in this clone. Possib     

THE POSITIVE PERIODIC SOLUTIONS OF PERIODIC RFDEs WITH INFINITE DELAY

This paper is concerned with the periodic retarded functional differential equati-ons(RFDEs) with infinite delay. The sufficient conditions for the existence of noncon-stant positive periodic solutions are established by combining the theory of monotone semiflows generated by RFDEs with infinite delay and the fixed point theorems of solution operators. A nontrivial application of the results obtained here to a well-known nonautonomous Lotka-Volterra system with infinite delay is also presented.     

双缝孔径像面强度全息术及其应用

本文分析了利用透镜成像的像面强度全息图的衍射特性,提出了利用双缝孔径记录像面强度彩虹全息图的方法,同时给出了实验结果。     

Feynman Identity: A Special Case Revisited

It is proved that a special case of Feynman identity is a consequence of the generalized Witt identity of some Lie algebra. Mathematics Subject Classifications (2000): 82B20, 05A19, 17B01.     

基于BDRM理论的深海声场快速预报研究

深海存在深海声道和双轴声道两种典型环境，WKBZ简正波方法已实现了深海声道中声场的快速准确预报，而对于双轴海洋声道则存在一定的误差。本文在WKBZ本征函数的基础上，推导出了参考界面相位修正的一致表达式，并将浅海声传播的波束位移射线简正波（BDRM）理论应用于计算双轴海洋声道中的声场，进行了数值模拟并与传统简正波方法进行比较，结果表明应用BDRM理论计算的传播损失具有很高的精度和速度。     

Stress Controlled Silicon Nitride Thin Film Deposited by Plasma Enhanced Chemical Vapour Deposition

SiN, films are deposited on silicon wafers through plasma enhanced chemical vapor deposition （PECVD）. The relationship between the film stress and deposition factors is investigated. It is found that low stress films would be obtained by adjusting the ratio of low frequency（LF） power to high frequency（HF） power pulse time or the chamber pressure. The best of the two methods to control stress in the film is changing the percentage of LF power pulse time. The low stress condition is achieved when the percentage of low frequency power pulse time in total time（LF and HF pulse time） is close to 40%, The low stress cantilever of tunable vertical cavity surface emitting laser is obtained by using this deposition condition,