ICP-MS测定无公害畜禽饮用水中铅、汞、砷和镉

用ICP-MS测定畜禽饮用水中铅、汞、砷、镉的含量,其最终结果与现行国家标准方法一致。     

Study of new boson W_1~± in the Minimal Higgsless Model at the LHC

The Minimal Higgsless Model predicts the existence of new vector gauge boson W1± . By the process PP → W1± qq → W±Z0qq, Z0 → l+l-, W±→ qq (l=e,μ; q is hadronized to be jets), we study the sensitivity of searching for this possible vector gauge boson in the level of generator events of signal and backgrounds, then give integrated luminosity required to discover 5σ signal as a function of W1± mass. The generator for the signal PP→W1± qq→W±Z0qq at tree level is developed with the Minimal Higgsless Model and th...     

Optimal Capacity Allocation on Heterogeneous Complex Transport Networks

We study how the node delivering capacity is allocated so that the traffic transport efficiency can be enhanced maximally. Network heterogeneity of degree distribution and processing delay of the traffic are considered. An explicit analytical solution is provided, which is based on the M/M/1 queueing theory and optimization principle, provided that the network structure and routing strategy are given. In particular, we extend the relevant conclusions in the literature [Europhys. Lett. 83 （2008） 28001]. Finally, an order parameter simulation example by comparing results with those obtained via simple capacity allocation in large Barabasi—Albert （BA） scale-free network is provided to illustrate the effectiveness of the theoretical results.     

复杂铝合金零件镀银工艺改进

介绍了复杂铝合金零件镀银工艺,分析了影响铝合金电镀层质量的因素,通过试验改进了铝合金电镀工艺,在常规二次浸锌工艺中增加了电镀锌,采用浸锌电镀锌联合处理法提高了复杂铝合金零件镀银的结合力。给出了工艺流程及各工序溶液配方和相关参数,并提出了相应的操作要点。介绍了生产过程中易出现的问题及解决办法。利用划格法和热震法检验了镀层的结合强度。测试结果表明:采用新工艺加工的零件达到了结合力的要求。     

激光的复宗量厄米-高斯相干模表示

利用部分相干光理论,以具有双正交性质的复宗量厄米-高斯(EHG)模为基底,推导出激光的EHG模相关系数(MCCs)和M2因子公式,建立了激光的EHG相干模表示与对应的常规厄米-高斯(SHG)相干模表示之间的关系,并讨论了两种典型的应用例.研究结果表明,激光的EHG模相关系数可以通过SHG模相关系数得到;当同阶模式的权重因子相同时,由彼此互不相关的EHG模式叠加而成的光束比由彼此互不相关的SHG模式叠加而成光束的光束质量更好.     

基于分级结构的优化QoS路由算法北大核心

Ad hoc(自组织)网络中包含延迟、延迟抖动、带宽和丢包率等约束条件在内的QoS(服务质量)路由问题,是一个NP完全问题,传统的平面QoS蚂蚁路由算法难以解决提高算法全局搜索能力和加快收敛速度之间的矛盾。针对以上问题,提出了HQAC(分级QoS蚁群)算法,在分级的基础上对蚁群算法的路由搜寻过程进行了改进,同时对信息素更新公式进行了优化。仿真结果表明,与传统的QoS路由算法相比,HQAC算法在搜索全局最优解,尤其是收敛速度等性能上有了很大的提高。     

Ratio of a strange quark mass ms to up or down quark mass mu,d predicted by a quark propagator in the framework of the chiral perturbation theory

Based on the fully dressed quark propagator and chiral perturbation theory, we study the ratio of the strange quark mass ms to up or down quark mass mu,d . The ratio is related to the determination of quark masses which are fundamental input parameters of QCD Lagrangian in the Standard Model of particle physics and can not be directly measured since the quark is confined within a hadron. An accurate determination of these QCD free parameters is extremely important for both phenomenological and theoretical applications. We begin with a brief introduction to the non-perturbation QCD theory, and then study the mass ratio in the framework of the chiral perturbation theory (χPT) with a parameterized fully dressed quark propagator which describes confining fully dressed quark propagation and is analytic everywhere in the finite complex p2-plane and has no Lehmann representation so there are no quark production thresholds in any theoretical calculations of observable data. Our prediction for the ratio ms/mu,d is consistent with other model predictions such as Lattice QCD, instanton model, QCD sum rules and the empirical values used widely in the literature. As a by-product of this study, our theoretical results, together with other predictions of physical quantities that used this quark propagator in our previous publications, clearly show that the parameterized form of the fully dressed quark propagator is an applicable and reliable approximation to the solution of the Dyson-Schwinger Equation of quark propagator in the QCD.     

自适应的端到端可用带宽测量方法

提出了一种轻负载的、自适应的端到端可用带宽测量方法.在低负载链路下,计算探测包对距离增大的概率,结合输出探测包距离分布,得到可用带宽.在此基础上通过探测包输出包距离对称度区分链路负载情况,自适应地采用合适的可用带宽计算方法.仿真实验表明,相比之前方法,本方法测量时间少、准确性高、测量开销小.     

极低信噪比下对偶序列跳频信号的随机共振检测方法

针对对偶序列跳频(DSHF)在极低信噪比(SNR)下无法通信的问题,该文充分利用对偶序列跳频信号时、频域物理特征,提出一种随机共振(SR)检测方法,极大扩展该信号的应用场景。首先,通过分析对偶序列跳频的发射、接收信号及超外差解调的中频(IF)信号,构建随机共振系统,采用尺度变换调整中频信号;然后,引入判决时刻,将无定态解的非自治福克普朗克方程(FPE)转化为可解的自治方程,从而推导出含时间参量的概率密度周期定态解;其次,以最大后验概率为准则,得到检测概率、虚警概率和接收机工作特性(ROC)曲线;最后,得出以下结论:(1) 应用匹配随机共振检测对偶序列跳频信号的信噪比最低可达–18 dB;(2)对偶序列跳频与匹配随机共振结合,适用于信噪比在–18～–14 dB的信号检测;(3)应用匹配随机共振检测对偶序列跳频信号在信噪比为–14 dB时,检测性能提升了25.47%。仿真实验验证了理论的正确性。     

OLED用偏光片的研究进展

介绍了OLED用偏光片的发展历程,原理和效用。最后对OLED用偏光片的结构提出了更轻薄的要求,预测了其应用趋势和市场发展。