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排序方式: 共有62条查询结果,搜索用时 15 毫秒
1.
针对铭文中出现的反书、倒书等特殊形式的书写现象,本工作采用泥条贴范法,从铭文制作的工艺角度对反书和倒书进行了讨论,并搭建了一套以树叶刻字为基础的推论模型,通过模拟实验进一步地阐述了在此模型下反书和倒书的产生的可能性及原因。  相似文献   
2.
Many factors governed the penetration efficacy of prehistoric projectile weaponry. Archaeologists broadly focus their efforts on understanding the effect of stone weapon tips because these specimens are often the only part of the weapon system that survives in the archaeological record. The tip cross-sectional area (TCSA) and perimeter (TCSP) of stone weapon tips have been shown to correlate with target penetration depth. Here, using results from both static and dynamic penetration testing, we compare TCSA and TCSP against other tip geometry metrics: lateral surface area (LSA) and volume (V). Our analyses broadly show that using a single-point geometry metric evaluated at multiple locations along the length of the point, or using multiple geometry metrics evaluated at a single location, better predicts required energy than using a single-point geometry metric evaluated at a single location. Our results also show that in the case where a single geometry metric evaluated at multiple locations is used LSA provided the most robust prediction models. Finally, our results show that for the case where all geometry metrics evaluated at a single location are used the location that provides the most robust prediction model is dependent on how far the point penetrated the target.  相似文献   
3.
明朝初年,国脉皆仰东南,为解决南方粮财物的北运问题,宋礼和白英受命组织修建了大运河山东段南旺分水枢纽。该枢纽主要包括引汶济运、导泉补源、设立水柜和置闸节流四个组成部分。其中,引汶济运是工程之重点,包括戴村坝、小汶河、南旺分水以及配套工程等四个子系统。这些水利设施组成一个和谐的系统工程,保证了该段运河的水量稳定充足,从而实现了大运河500余年的正常通行。南旺分水枢纽代表了我国古代运河水工的最高科学技术成就,堪称世界水利史上的一大经典范例。  相似文献   
4.
This paper discusses studies of the development of river conservancy in modern China, and the role of engineers-in-chief in river improvement planning on rivers such as the Hai-ho (Haihe) and the Whangpoo (Huangpu). It discusses the introduction of foreign hydraulic dredging technology and management into two major Chinese ports. It then analyses the process by which two agencies of the Chinese government absorbed and adjusted this technology to suit local circumstances in the treaty ports of Tianjin and Shanghai beginning in the 1890s. Without prior experience in river conservancy, the conservancy boards adopted a range of foreign technologies. This allowed them to develop into major institutions that facilitated increasing trade flows between China and the rest of the world. Of particular significance in this process of technological change was the role of the expatriate engineers-in-chief who were employed as chief executive officers of both agencies. They were responsible for establishing the operations of the agencies, accommodating an increasing range of responsibilities such as financial and human resource management, and training Chinese engineers and managers for senior positions until they were ready to replace the expatriate engineers-in-chief after the 1930s.  相似文献   
5.
农业系统是一个开放的复杂大系统。系统的功能决定于系统的结构,合理的农业结构应该是充分合理利用农业自然资源和社会经济资源,因地制宜发挥地区的优势,使农业生态效益与经济效益相结合,构成良性循环,达到低投入,高效益,持续稳定增产的目的。本文根据农业系统的开放性、复杂性和层次性,利用系统工程中的结构分解--协调法计算出南宁地区左江流域六县(市)最优的农业结构,即合理的农业结构。为该地区制定经济发展规划提供科学依据。  相似文献   
6.
前视全景钻孔电视在龙门石窟防渗工程中的应用   总被引:1,自引:0,他引:1  
影响龙门石窟雕刻艺术品长期保存的主要病害是渗水,卸荷裂隙往往切割洞窟、隙宽较大而成为洞窟渗水的主要通道。为查明洞窟卸荷裂隙的分布位置,最可靠的方法是在现场进行水平钻探。但受钻探施工的干扰,钻孔岩芯可能在钻探取芯的过程中造成折断或破裂,钻孔取芯率也会相对较低,因而仅靠观测岩芯难以确定卸荷裂隙的准确部位。为此,采用有潜在价值的钻孔电视方法,以识别不同的岩层,确定裂隙的分布情况及裂隙中的充填物。研究结果表明钻孔电视在龙门石窟防渗工程中取得成功的应用,说明这是一种值得在岩土文物保护工程中推广应用的新技术。  相似文献   
7.
韩云霞 《攀登》2009,28(3):131-132
“广播电视村村通”工程是农牧区广播电视事业发展的载体,是解决边远山区农牧民群众看不到电视、听不到广播难题的“民心工程”。要因地制宜,探索建立农牧区广播电视公共服务体系,搞好“广播电视村村通”工程建设。  相似文献   
8.
李贺文 《神州》2011,(3X):1-2,4
从对兰州理工大学技术工程学院大学生人文素质现状的抽样调查来看,由于专业教育的偏向和较低的高考成绩,使得理工科独立学院学生的人文素质普遍偏低。因此加强理工科独立学院大学生的人文素质教育就显得尤为重要,而这可以试着从理工科学生的培养模式、考核方式及教师队伍建设、政策鼓励等方面做出一定的改进,以提高理工科大学生学习人文知识的兴趣和机会,以保障人文素质教育在理工科学生中的顺利开展,使其成为一个和谐发展的人。  相似文献   
9.
Abstract

Cahokia (a.d. 800–1400), located near the confluence of the Mississippi and Missouri rivers, was the largest settlement in ancient North America. Monks Mound occupies the center of Cahokia and provides both a modern and ancient focal point for the site. Past investigations of Monks Mound explored issues of mound chronology and use. Recent soil coring around the perimeter clarifies the geological context and degree of preparation necessary before the mound was built. The results suggest that the mound is not optimally positioned for stability and its location may ultimately accelerate deterioration. Moreover, evaluation of the mound features and fill indicates that maximization of the geotechnical potential of sediments was not a primary concern for the Cahokians. Although poorly engineered relative to modern standards, the suitability of the mound as a platform may have been secondary to other design choices made while building the largest single mound in ancient North America.  相似文献   
10.
In this paper a method for the identification of simplified linear models for building structures is applied to the case when acceleration, rather than displacement, is measured. A frame from benchmark structural controller studies is simulated, and from the input-output data of these simulations, simplified models for the acceleration response of the frame are obtained that have far fewer degrees of freedom. One of these simplified models is used to design a controller, which is tested using an evaluation model from the benchmark controller studies and found to be effective.  相似文献   
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