Traffic estimation based on long short-term memory neural network for mobile front-haul with XG-PON

A novel predictive dynamic bandwidth allocation(DBA) method based on the long short-term memory(LSTM)neural network is proposed for a 10-gigabit-capable passive optical network in mobile front-haul(MFH) links. By predicting the number of packets that arrive at the optical network unit buffer based on LSTM, the round-trip time delay in traditional DBAs can be eliminated to meet the strict latency requirement for MFH links. Our study shows that the LSTM neural network has better performance than feed-forward neural networks. Based on extensive simulations, the proposed scheme is found to be able to achieve the latency requirement for MFH and outperforms the traditional DBAs in terms of delay, jitter, and packet loss ratio.     

一种一维超分子链状四核镍夹心砷钨酸盐的合成和表征(英文)

利用水热方法合成了一种一维超分子链状四核镍夹心的砷钨酸盐[enH2][Ni(en)2]4[Ni4(H2O)2(α-AsW9O34)2].10H2O(1)(en=ethylene diamine);借助元素分析、红外光谱和单晶X射线衍射对其进行了表征。结果表明,化合物1的分子结构单元由1个二支撑的四核镍夹心砷钨酸盐多阴离子{[Ni(en)2]2[Ni4(H2O)2(α-AsW9O34)2]}6-,2个游离的[Ni(en)2]2+配离子,1个游离的双质子化[enH2]2+阳离子和10个结晶水分子组成。有趣的是,相邻的四核镍夹心砷钨酸盐多阴离子{[Ni(en)2]2[Ni4(H2O)2(α-AsW9O34)2]}6-借助Ni…O弱相互作用构筑一维超分子链状结构[Ni…O距离分布在0.253 2～0.283 7nm之间]。     

60Coγ射线对高铝组分Al0.5Ga0.5N基p-i-n日盲型光探测器理想因子的影响

采用⁶⁰Co γ射线源对高铝组分Al_0.5Ga_0.5N盲紫外p-i-n结构光探测器和Si基可见光p-i-n结构探测器进行了累计剂量分别为0.1, 1, 10 Mrad(Si)总剂量辐照实验. 实验发现, 随着辐照剂量的增加, AlGaN盲紫外p-i-n结构光探测器的理想因子显著增大, 辐照后理想因子n > 2; 而Si基可见光p-i-n 结构探测器的理想因子随辐照剂量的变化并不明显. AlGaN盲紫外p-i-n结构光探测器理想因子的退化可能主要是因为欧姆接触性能的退化, Si基可见光p-i-n结构探测器的理想因子的变化则可能是由于敏感层的退化. 关键词： xGa_1?xN')" href="#">高铝组分Al_xGa_1?xN γ射线辐射效应 理想因子 欧姆接触     

不完美维护活动干预下的设备剩余寿命估计

剩余寿命估计是保障设备安全性和可靠性的关键技术。现有文献在研究维护活动干预下的设备剩余寿命估计问题时,通常仅考虑维护活动对退化水平或退化速率的单一影响,忽略了维护活动对两者的双重影响。鉴于此,提出了一种考虑不完美维护活动影响的性能退化建模与剩余寿命估计方法,融合了维护活动对设备退化水平和退化速率的双重影响。首先基于扩散过程分阶段建立存在不完美维护活动干预下的随机退化模型,然后基于设备的状态监测数据和维护数据对模型参数进行极大似然估计和Bayesian更新,最后在首达时间的概念下,推导得到了剩余寿命的解析概率分布。实验结果表明,所提出方法能够大大提高存在不完美维护活动影响设备的剩余寿命估计精度。     

Ab initio studies on n-type and p-type Li4Ti5O12

This paper studies the structure and electronic properties of Li4Ti5O12, as anode material for lithium ion batteries, from first principles calculations. The results suggest that there are two kinds of unit cell of Li4Ti5O12: n-type and p-type. The two unit cells have different structures and electronic properties:the n-type with two 16d site Li ions is metallic by electron, while the p-type with three 16d Li ions is metallic by hole. However, the Li4Ti5O12 is an insulator. It is very interesting that one n-type cell and two p-type cells constitute one Li4Ti5O12 supercell which is insulating. The results show that the intercalation potential obtained with a p-type unit cell with one additional electron is quite close to the experimental value of 1.5 V.     

离子液体在制备金属氧化物纳米材料中的应用

总结了近年来在离子液体中制备金属氧化物纳米材料的新方法以及离子液体在金属氧化物纳米材料制备方面的应用及发展趋势.目前,对于制备纳米金属氧化物,离子液体主要是作为电解液、表面活性剂;其未来的发展趋势是离子热合成和集模板-溶剂-反应物于一身的离子液体反应.     

两分量Bose-Einstein凝聚体的非线性Ramsey干涉

以非线性Rosen-Zener隧穿理论为基础,用两分量Bose-Einstein凝聚体设计了非线性Ramsey干涉计.通过数值模拟实验在时间域上观察到了丰富的Ramsey干涉图样,凝聚体中原子间重要的非线性相互作用导致这些干涉图样明显不同于线性Ramsey干涉时的正弦型条纹.通过进一步对干涉图样作Fourier分析,发现干涉图样的基频能够精确反映系统的非线性和不对称性特征,从而为测量原子的相关性质提供了理论依据. 关键词： Bose-Einstein凝聚 非线性Ramsey干涉 Rosen-Zener隧穿     

大学物理实验教学改革的实践与探索

对我校大学物理实验教学存在的弊端进行了分析,指出了大学物理实验教学改革的思路、内容和方法,并付诸实践,取得了较好的效果.     

BIFURCATION AND STABILITY ANALYSIS FOR LIQUID SURFACES

A more comprehensive discussion on the bifurcation problems for the shape of liquidsurfaces is made in this paper.The necessary conditions for bifurcation are given,and thebifurcating solutions near bifurcation points can be obtained by perturbation technique.Finally the stability of the bifurcating states is analyzed by means of the principle ofminimum potential energy.