CeNi5—xCux吸氢性能研究

样品在氩气氛下采用高频感应炉制备,所有样品经过均匀化热处理。在20,40和60℃下测量CeNi_(5-x)Cu_x饱和吸氢量,吸氢动力学曲线和放氢曲线。 在20和40℃,CeNi_3Cu_2压力一组成等温图中有较宽和明显的平台压力区,吸、放氢速度较快。若用Cu取代CeNi_5中部分Ni则成本可有所降低。CeNi_3Cu_2是很有发展前途的贮氢材料。CeNi_5和CeNi_4Cu在相同条件下不具有吸氢性能。CeNi_(5-x)Cu_x具有CaCu_5结构。     

THE CONNECTIVITY OF MAXIMUM MATCHING GRAPHS

The maximum matching graph of a graph has a vertex for each maximummatching and an edge for each pair of maximum matchings which differ by exactly oneedge. In this paper, we prove that the connectivity of maximum matching graph of abipartite graph is equal to its minimum degree.     

一类短期利率模型的最优估计、选择与定价应用

对CKLS的一般无约束模型进行了推广,提出了两个更为一般的无嵌套短期利率模型,并以中国银行间债券市场国债回购利率R007的日数据为样本,对这两个模型以及可嵌套在CKLS框架下的GBM模型、Vasicek模型和CIR SR模型的欧拉离散化形式进行了极大似然估计（MLE）.在此基础上,采用对数似然比和Vuong检验统计量,对它们的模型拟合效果进行了比较,结果表明对CKLS模型推广的第二种形式（模型5）优于其他四个模型.然后,又利用间接推断方法对模型5估计得到的初始参数值的偏差进行校正,并将修正后的参数估计值及其短期利率扩散模型用于对某上市公司的股票看涨期权进行定价.     

模糊推理的模糊熵三I算法及其还原性

讨论FMP问题的模糊熵三I算法解的存在条件,研究了三I解与模糊熵三I解的关系,获得了模糊熵三I算法的一般计算公式,并给出了几个重要蕴涵算子的模糊熵三I算法公式,证明了这些算法在一定条件下是还原算法.     

Imprint of solar activity on Nanjing stalagmite annual layer thickness sequence during the Last Glacial Maximum

PREVIOUS STUDIES ON ANNUAL GROWTH LAMINAE IN STA-LAGMITES SUGGESTED THAT IT IS A USEFUL PROXY TO INVESTI-GATE ANNUALLY HIGH-RESOLUTION CLIMATES[1―4].THE VARIA-TION OF ANNUAL LAMINAE THICKNESS HAS BEEN EXPLAINED AS REFLECTING SEASONAL CHANGES EITHER IN DR…     

扩程电阻的误差分析

本文利用误差理论导出了扩程电阻的误差表达式，并对扩程电阻的误差与各物理量的关系进行了分析，寻找出了规律。对误差的来源以及大小从理论上得到了明确的解释。     

A palynological and palaeoclimatological record from the southern Philippines since the Last Glacial Maximum

A palynological analysis of a marine sediment core in the southern Philippines,provides a detailed regional vegetation and climate history for the West Pacific Warm Pool(WPWP)since the Last Glacial Maximum(LGM).Chronology was determined by a detailed oxygen isotope record.A higher representation of pollen from tropical upper montane rainforest during the LGM indicate that this forest type moved down along elevation,probabaly due to the lowered temperature.During the last deglaciation and the early Holocene,mangroves were more expanded and tropical mid and upper montane rainforests were restricted,suggesting a rising sea-level and temperature increase.Herbaceous pollen and pteridophyte spore records indicate a much drier condition during the LGM than the Holocene.Mangrove development is controlled by conditions at the river mouth influenced by river discharge.Pteridophyte spores are abundant in wet conditions and are mainly transported by rivers.During the mid-Holocene,the reduction in mangrove pollen and pteridophyte spore appears to be a result of climate change:mainly decrease in river discharge.This may have been affected by the decreasing intensity of the Southeast Asian Monsoon,and the increasing frequency and intensity of warm ENSO events,El Ni?o,in this region.     

一种利用LSTM和稳态时间序列的光伏阵列故障诊断方法

针对光伏阵列电气工作参数包含复杂的暂态过程及工频干扰噪声严重影响故障诊断模型性能的问题,提出一种基于最大功率点的稳态时间序列预处理方法.首先,以自动过滤数据中的暂态过程和干扰噪声,获取连续的稳态时间序列电气特征数据,作为故障诊断模型的输入参数;然后,提出一种基于长短期记忆网络的深度网络模型,以实现对光伏阵列常见故障的检测及分类;最后,在一个小型光伏并网发电系统及其Simulink仿真模型上,进行故障模拟及仿真,以验证所提出的故障诊断方法.实验结果表明,所提出的故障诊断方法具有良好的精度和泛化性能,并且优于常规的反向传播神经网络和循环神经网络.     

有纵向底坡弯道急流的二维解析解

本文通过对水流运动的欧拉(Eulcr)方程和连续方程按小扰动原理进行线性化处理,然后求其波动方程的解。导出了有纵向底坡时,通过明渠弯道的水流波动周期、第一波峰位置及该点最大水深的解析式,并经试验进行了验证。计算与试验表明,当弯道的纵坡i(i=tgα)在所试验的范围内(tgα<5％)时,它对弯道的水力特性影响很小,可按平坡计算。     

长记忆过程参数的小波包极大似然估计方法

基于小波包变换的解相关属性,对传统方法进行了改进,提出并推证了一种小波包极大似然估计(WPMLE)方法,并将它应用到一类有非常广泛应用背景的长记忆过程中去.仿真结果表明,在一定的精确度要求下,这种近似算法极大地降低了参数估计的计算量,可以作为参数估计方法的一种很好的选择.