北宋东京开封外城的历史演革

来源 :科技资讯 | 被引量 : 0次 | 上传用户:hngyssh
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
北宋东京外城来源于五代后周时期所修的罗城。北宋时期,修筑了瓮城、马面、敌楼等防御设施。城墙内外皆为夯土,十分坚固。除了加固城体之外,北宋时还对外城南墙进行外扩,以增加城市容量。城墙外围有护城河,河宽水深。
其他文献
The problem of the robust D-stability analysis for linear systems with parametric uncertainties is addressed.For matrix polytopes,new conditions via the affine
With applying the information technology to the military field,the advantages and importance of the networked combat are more and more obvious.In order to make
采用甘油作为聚乙烯醇(PVA)的塑化改性剂,实现了PVA的热塑成型,以超临界二氧化碳(scCO2)为物理发泡剂,采用间歇式降压法制备了一系列PVA泡沫材料。利用差式扫描量热仪和流变仪系
An adaptive algorithm named low complexity phase offset estimation (LC-POE) is proposed for orthogonal frequency division multiplexing (OFDM) signals. Depending
通过对川滇地区M≥7地震余震序列活动早期衰减特征的研究,发现序列基本上符合G-R关系,大、小地震成比例,序列中的最大强余震小于或等于用序列拟合计算b值截距得到的最大地震,
In the methods of image thresholding segmentation,such methods based on two-dimensional(2D) histogram and optimal objective functions are important.However,when
Methods of the comprehensive evaluation have been studied for many years.However,the change speed of evaluated objects was rarely considered by the existing eva
The existing trajectory clustering(TRACLUS) is sensitive to the input parameters ε and MinLns. The parameter value is changed a little, but cluster results are
<正>2018年,农发行江苏省分行营业部认真贯彻落实总分行脱贫攻坚各项决策部署,切实增强扶贫工作责任感、使命感和紧迫感,精准把握对口帮扶、协作扶贫等切入点,努力推动各种资
现今社会,科技发展日新月异,微信、互联网等新兴媒体迅速崛起,大大削减了电视节目作为人们日常获取新闻信息的霸权地位。为此,传统的电视新闻节目面临着巨大的挑战,为了要谋