人口问题中一般扩散模型的径向对称解

研究四阶非线性抛物方程初边值问题的径向对称解. 采用抛物正则化方法, 借助Campanato空间框架和一致Schauder型估计, 得到了正则化问题古典解的存在性, 并基于正则化问题解的一些必要一致估计, 证明了弱解的存在性.     

碱污染下红黏土强度指标变化的微观角度分析

为了研究碱性环境条件下桂林红黏土强度指标变化机制,对不同质量分数NaOH溶液污染下的红黏土开展直剪试验、物化分析试验、颗粒分析试验以及比表面积试验,进而探究地基土体宏观力学指标与微观结构之间的关系.研究结果表明:随着NaOH质量分数的增加,黏聚力逐渐增大,内摩擦角逐渐减小.随着孔隙溶液中Na+质量分数的增加,微小土颗粒...     

Positivity and Stability of Fractional-Order Linear Time-Delay Systems

This article focuses on the positivity and the asymptotic stability of fractional-order linear time-delay systems(FOLTDSs) which are composed of N(N ≥ 2) subsystems. Firstly, a sufficient and necessary condition is given to ensure the positivity of FOLTDSs. The solutions of the studied systems are obtained by using the Laplace transform method, and it can be observed that the positivity of FOLTDSs is completely determined by the series of matrices and independent of the magnitude of time-delays....     

基于小波变换的数字调制信号特征提取

小波变换的多分辨率特性对暂态信号有很强的检测能力,数字信号在不同码元之间呈现出幅度、频率和相位瞬变现象.文讨论如何利用小波变换对数字调制信号的瞬变特征进行提取,实验表明该方法对数字调制信号幅度、频率和相位的瞬变特征能够进行有效的检测.     

一种风光互补蓄电池能量管理系统的设计与仿真

为提高系统响应速度,缩短耗时,延长蓄电池的使用寿命,针对传统PI控制的不足,选取模糊控制优化蓄电池充放电控制,采用电压源型变换器平抑输出功率波动,设计了一种风光互补蓄电池能量管理系统。在MATLAB/Simulink平台搭建系统仿真模型,仿真结果显示,模糊控制响应速度快,控制效果好;并网电流与网侧电压保持同相位,跟踪性能好;设计的风光互补蓄电池能量管理系统具有良好的能量控制管理效果。     

图书馆自动化业务流程及金盘集成管理系统问题浅析

以贵州财经学院图书馆为例,系统地介绍了图书馆各部门利用金盘集成管理系统开展自动化业务的工作流程,分析了金盘图书馆管理系统在应用过程中遇到的问题,提出了改进金盘系统管理软件的建议。     

Structural properties of residual carbon in coal gasification fine slag and their influence on flotation separation and resource utilization: A review

Coal gasification fine slag (FS) is a typical solid waste generated in coal gasification. Its current disposal methods of stockpiling and landfilling have caused serious soil and ecological hazards. Separation recovery and the high-value utilization of residual carbon(RC) in FS are the keys to realizing the win-win situation of the coal chemical industry in terms of economic and environmental benefits.The structural properties, such as pore, surface functional group, and microcrystalline structu...     

Exome sequencing of gastric adenocarcinoma identifies recurrent somatic mutations in cell adhesion and chromatin remodeling genes

Gastric cancer is a major cause of global cancer mortality. We surveyed the spectrum of somatic alterations in gastric cancer by sequencing the exomes of 15 gastric adenocarcinomas and their matched normal DNAs. Frequently mutated genes in the adenocarcinomas included TP53 (11/15 tumors), PIK3CA (3/15) and ARID1A (3/15). Cell adhesion was the most enriched biological pathway among the frequently mutated genes. A prevalence screening confirmed mutations in FAT4, a cadherin family gene, in 5% of gastric cancers (6/110) and FAT4 genomic deletions in 4% (3/83) of gastric tumors. Frequent mutations in chromatin remodeling genes (ARID1A, MLL3 and MLL) also occurred in 47% of the gastric cancers. We detected ARID1A mutations in 8% of tumors (9/110), which were associated with concurrent PIK3CA mutations and microsatellite instability. In functional assays, we observed both FAT4 and ARID1A to exert tumor-suppressor activity. Somatic inactivation of FAT4 and ARID1A may thus be key tumorigenic events in a subset of gastric cancers.     

浅谈发挥学生党员先锋模范作用机制建设

目前,高校大学生是建设中国社会主义事业的主力军和生力军,高校学生党员是党组织的重要组成部分.其先锋模范作用的充分发挥与否,不仅关系到高校党员教育培养目标的实现,而且关系到党的教育事业的发展和现代化建设的兴衰成败.     

基于SSA-GRU大功率多状态PEMFC寿命预测

提出了一种用于最大额定功率为110 kW的质子交换膜燃料电池(proton exchange membrane fuel cell, PEMFC)剩余使用寿命的麻雀搜索算法优化门控循环单元的方法,进行了超过600 h的动态循环耐久试验,以模拟不同路况下车载PEMFC的工作情况。为准确预测大功率PEMFC的剩余使用寿命,需考虑其在不同工作状态下输出电压,将输出电压根据不同功率点进行分类预测。将采样数组经过滤波处理,减少峰值,平滑降噪,然后基于数据驱动的方法以各工作状态下电压数据以及不同的训练集划分作为输入,并预测结果通过选取的评价指标与不同的常见时序回归算法证实此模型的准确性。以数据的60%作为训练集为例,麻雀搜索优化门控循环单元(sparrow search algorithm-gate recurrent unit, SSA-GRU)的预测结果对比时间卷积网络(temporal convolutional network, TCN)其平均绝对百分比误差(mean absolute percentage error, MAPE)在30、50、70、90、110 kW分别降低了0.110...