昆明气温骤降与感冒发病率相关性研究     

毕家顺 《气象科技》2006,34(6):728-730

研究昆明气温骤降与感冒发病率的相关关系,对预防感冒具有一定意义。应用概率统计方法,讨论了季节性极端天气条件与感冒的关系。通过对感冒与冷空气活动过程的分析,找出了冬半年中容易引发感冒的气象因子。得出的结果表明,极端天气条件作为气候应激因子与感冒发病有密切关系。  相似文献   

TTI介质中波传播的伪谱法折叠效应的消除方法研究     

轩义华  秦成岗  赵仁永  张忠涛  丁琳  李小平 《物探化探计算技术》2007,29(6):473-476

在弹性波传播问题的研究中,伪谱法是一种很好的模拟方法。该法的最大优点是节省存储空间,运算速度优于其它方法。但是伪谱法也存在一定的问题,由于折叠效应的影响,普通的吸收边界条件不能达到良好的效果。所以,这里采用一种"反周期延拓"与普通吸收边界相结合的新办法,用来消除折叠效应和边界反射的影响,并在TTI介质的伪谱法正演模拟中加以应用。模拟结果表明,这种新的方法能有效地达到消除伪谱法正演模拟过程中所产生的折叠效应,具有一定的推广价值。  相似文献   

公共背景法在X射线荧光光谱分析化探样品中的应用   总被引：2，自引：3，他引：2  

魏培德 《岩矿测试》2002,21(2):147-149

在X射线荧光光谱分析化探样品时 ,对Co、Ni、Cu、Zn、Rb、Sr、Y、Zr、Nb、Pb和Th选择一个公共背景点 ( 2 9.60°) ,1 1种元素的检出限≤ 3× 1 0 - 6,能满足化探分析的要求。对国家一级水系沉积物标准物质进行测定 ,结果与标准值相符 ,8次测定的相对标准偏差RSD <7%。  相似文献   

长江口沉积物全量硼的测定初探   总被引：1，自引：0，他引：1  

姚荷孙  陈中原  李绿芊  韦桃源  赵怡文 《上海国土资源》2002,(2):17-21

利用ICP－AES测试方法准确测定长江口水下沉积物中的全量硼，对三种不同的样品消化方法进行了初步探索，我们认为HF－HCIO4－HNO3-H3PO4消化方法是可靠的理想的样品消化方法。  相似文献   

利用普通水准仪高精度监测建筑基础沉降   总被引：1，自引：0，他引：1  

姜晨光 《四川测绘》2002,25(1):35-37

介绍了利用普通水准仪高精度监测建筑基础沉降的特制器具和设备 ,叙述了相关的观测要领、方法及精度指标  相似文献   

Superintelligence and Natural Resources: Morality and Technology in a Brave New World     

Robert Todd Perdue 《社会与自然资源》2017,30(8):1026-1031

A growing majority of artificial intelligence (AI) scientists and engineers believe human-level intelligence will be attained before the dawn of the 22nd century, while a large number believe this will happen much sooner. At this point, the elevation to “superintelligence,” or systems that have superhuman levels of general intelligence, would likely proceed very rapidly. With this in mind, this commentary has three goals: (1) to provide an overview of how a leading scholar, Nick Bostrom, conceives of superintelligence, with its potential and risks, (2) to bring attention to a burgeoning form of common pool resource extraction, space mining, that may benefit from superintelligence management, and (3) to suggest that environmental social scientists should play a key role in programming seed AI, infusing it not only with our existing collective knowledge, but also with just values.  相似文献   

The Ideology of U.S. Agriculture: How Are Integrated Management Approaches Envisioned?     

Katherine Dentzman  Raymond Jussaume 《社会与自然资源》2017,30(11):1311-1327

The ease and affordability of the herbicide glyphosate and the development of glyphosate tolerant crops has encouraged a simplified weed management system in the U.S. However, the overuse of this technological package in recent years has led to an explosion in the number of herbicide resistant weeds and a decrease in the effectiveness of glyphosate. In addition to this bio-chemical problem, many growers appear to be stuck within a farming ideology that focuses on a reduction in time/labor, an increase in profitability and a vision of ever-increasing efficiencies of scale. This may prevent them from conceptualizing and implementing solutions that fall outside of a simple herbicide application plan. The objective of this paper is to begin describing the current ideology of industrial corn and soybean farmers in the United States, as well as how this ideology contributes to farmers’ resistance to complex weed management strategies.  相似文献   

数字太原地理空间框架建设项目方案探讨   总被引：2，自引：0，他引：2  

陈弘奕 《地理空间信息》2008,6(5):30-32

介绍了“数字太原”地理空间框架建设的目标、数据形式、系统结构、技术路线和流程,具体说明了地理空间信息平台的建设中的数据内容和地址数据的采集方法,详细介绍了地籍管理系统、矿产资源管理系统、环保监测信息系统、公众服务地理信息系统的建设内容。  相似文献   

THE MONUMENT AND THE BUNGALOW     

PEIRCE LEWIS 《Geographical review》1998,88(4):507-527

ABSTRACT. Students of human landscapes often view those landscapes as documents and seek to “read” them for cultural and historical meaning. But how does one learn to read landscape? And how can students be taught to do it? After many years of teaching courses about commonplace American landscapes, I have discovered that students must learn two things before they can expect to read human landscapes. First, they must learn to pay attention to commonplace things which most Americans normally ignore. Second, they must master vocabularies that permit them to classify elements in the landscape and to connect small things with larger ideas. Two examples in the landscape of Bellefonte, Pennsylvania—the town's war memorial and a scattering of California bungalows-demonstrate how these ideas work.  相似文献   

转换横波共炮记录单程声波方程正演模拟   总被引：7，自引：1，他引：6  

熊高君  张毅祥 《物探化探计算技术》1998,20(3):213-217

本文分别把分离的纵波和横波方程分裂为各自的两个单向旁轴方程（Ｊ．ＦＣｌｅａｒ－ｂｏｕｔ）,然后用单程纵波和横波方程,结合相位移加有限差分混合波场延拓法（Ｄ．Ｒｉｓｔｏｗ）,在共炮记录叠前深度偏移原理的基础上,借鉴几何地震学的射线法两点问题原理,提出合成转换Ｐ—ＳＶ波共炮记录的时间一致性原理和逆过程方法,从而推导出精确的转换Ｐ—ＳＶ波共炮记录正演模拟算法,由于单程延拓波场,可完全解决多次反射波问题。  相似文献