拉丁方正交完全系和常用正交表的简捷构造法   总被引：1，自引：0，他引：1  

刘长安 《海洋湖沼通报》1995,(4):1-8

本文根据两个同阶拉丁方正交的定义和正交表的定义以及有关的数学理论，编制出拉丁方正交完全系和常用正交表的简捷构造法，提供给实验工作者使用并以此加深对拉丁方设计和正交设计的理解和掌握。设正整数ｍ〉２，本文在以下两种情形分别使用不同的方法构造ｍ阶拉丁方正交完全系：（１）ｍ为质数：以自然顺序的第１列为起点，从第２列开始，在列中依次进行数置换；（２）ｍ为质数幂：首先构造一个特定的标准拉丁方作为起点，然后从第  相似文献   

An experimenal analysis for the impact of 2D variation assimilation of satellite data on typhoon track simulation     

Xie Hongqin  Wu Zengmao  Gao Shanhon 《海洋学报(英文版)》2003,22(4):511-522

A series of test simulations are performed to evaluate the impact of satellite-derived meteorological data on numerical typhoon track prediction. Geostationary meteorological satellite (GMS-5) and NOAA‘s TIROS operational vertical sounder (TOVS) observations are used in the experiments. A twodimensional variation assimilation scheme is developed to assimilate the satellite data directly into the Penn State-NCAR nonhydrostatic meteorological model (MM5). Three-dimensional objective analyses fields based on T213 results and routine observations are employed as the background fields of the initialization. The comparisons of the simulated typhoon tracks are also carried out, which correspond respectively to the initialization scheme with two-dimensional variation (2D- Var), three-dimensional observational nudging and direct assimilation of satellite data. It is found that, comparing with the experiments without satellite data assimilation, the first two assimilation schemes lead to significant improvements on typhoon track prediction. Track errors reduce by 18% at 12 h for 2D- Var and from about 16% at 24 h to about 35% at 48 h for observational nudging. The simulated results based on assimilating different kinds of satellite data are also compared.  相似文献   

城市扩展对趵突泉泉域直接补给区保泉能力影响          下载免费PDF全文

孙斌  高文锋  魏月  雷炳霄  毕栋威 《山东国土资源》2020,36(4):55-60

直接补给区是趵突泉泉域重要的补给场所之一,随着城市发展其面积逐渐缩小。通过遥感手段解译60多年来济南城市发展趋势,分析揭示其对直接补给区面积及强渗漏小流域入渗功能的影响,采用大气降雨入渗系数法定量计算直接补给区面积削减对泉水保护的影响。结果表明,1954年—2015年,济南城市发展经历了平缓增长、快速增长、爆发式增长3个发展阶段,导致泉水直接补给区面积累计削减130km^2,约占总面积的29%,直接补给区内强渗漏小流域遭受不同程度破坏,6个渗漏功能完全丧失,9个渗漏功能部分丧失,仅9个渗漏功能保存近似完好,直接造成泉水入渗补给量减少约9.7万m^3/d(以多年平均降雨量648mm计)。直接补给区生态功能亟待保护与修复,应统筹管理小流域内山、水、林、土、草,加强小流域内山坡、山脚、山谷局部水循环的系统保护与修复,逐步恢复泉水补给能力。  相似文献   

Direct estimation of catchment response time parameters in medium to large catchments using observed streamflow data          下载免费PDF全文

O.J. Gericke  J.C. Smithers 《水文研究》2017,31(5):1125-1143

In single‐event deterministic design flood estimation methods, estimates of the peak discharge are based on a single and representative catchment response time parameter. In small catchments, a simplified convolution process between a single‐observed hyetograph and hydrograph is generally used to estimate time parameters such as the time to peak (T_P), time of concentration (T_C), and lag time (T_L) to reflect the “observed” catchment response time. However, such simplification is neither practical nor applicable in medium to large heterogeneous catchments, where antecedent moisture from previous rainfall events and spatially non‐uniform rainfall hyetographs can result in multi‐peaked hydrographs. In addition, the paucity of rainfall data at sub‐daily timescales further limits the reliable estimation of catchment responses using observed hyetographs and hydrographs at these catchment scales. This paper presents the development of a new and consistent approach to estimate catchment response times, expressed as the time to peak (T_Px) obtained directly from observed streamflow data. The relationships between catchment response time parameters and conceptualised triangular‐shaped hydrograph approximations and linear catchment response functions are investigated in four climatologically regions of South Africa. Flood event characteristics using primary streamflow data from 74 flow‐gauging stations were extracted and analysed to derive unique relationships between peak discharge, baseflow, direct runoff, and catchment response time in terms of T_Px. The T_Px parameters are estimated from observed streamflow data using three different methods: (a) duration of total net rise of a multipeaked hydrograph, (b) triangular‐shaped direct runoff hydrograph approximations, and (c) linear catchment response functions. The results show that for design hydrology and for the derivation of empirical equations to estimate catchment response times in ungauged catchments, the catchment T_Px should be estimated from both the use of an average catchment T_Px value computed using either Methods (a) or (b) and a linear catchment response function as used in Method (c). The use of the different methods in combination is not only practical but is also objective and has consistent results.  相似文献   

中空螺旋半合管直推取样建井工艺在污染场地调查中的应用研究          下载免费PDF全文

王青薇  尹业新  王水  王何琦  王瑜  钟道旭 《探矿工程》2022,49(3):154-159

污染场地土壤地下水的勘查需要同时满足取样和建井需求,中空螺旋半合管具有一定的自攻性,能够在获取低扰动土壤样品的同时建立地下水监测井。本文首先分析了中空螺旋的技术特点,同时基于直推式环境取样装备,提出中空螺旋半合管直推取样建井工艺,并在砂土相对密实度为0.46~0.83（12~16 m）的第四系砂土类地层进行项目试验。试验结果表明,该工艺能够有效解决传统直推取样工艺在土壤密实区域难以到达预定深度的难题,且岩心采取率>90%,是一种值得推广的环境取样技术。  相似文献   

永磁直驱变频泥浆泵在雄安地热钻井中的应用          下载免费PDF全文

李超  刘家荣  郭坤  刘文武  王玉超 《探矿工程》2021,48(2):100-103

泥浆泵作为钻井主要配套设备,在钻井施工中起着至关重要作用。目前大功率电动泥浆泵中多以交流异步电机驱动,气胎离合器、中间车、皮带轮减速的传动方式驱动泥浆泵。随着地热（干热岩）、页岩气等陆域清洁能源及深部资源勘探开发的需要,对大功率电动泥浆泵也提出了更高的要求。为此,在分析了雄安项目地热钻井的需求后,采用永磁变频电机直接驱动F-1300泥浆泵的小齿轮轴,具有传动结构简单、无级调速、节省能源、控制精度高的优势,适应了现代地热钻井技术的发展,提高了钻机的整体水平和作业能力,提高了钻井效率和质量。  相似文献   

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赵德军  徐新强  陈永祥  李帅鑫 《大地测量与地球动力学》2015,35(2):322-325

?????????????????????????????????????????????????????3?????棬??????????????????????????????3????????????????????????GPS/?????????????4?????????????“???????100 km????￡???????澫??±1 cm”????????|??????????????????????????|GOCE????????Ч???????????????????????????????  相似文献   

基于投入产出方法的气象服务综合经济效益评估     

吴亚玲  吴先华  郭际  陈云峰 《南京气象学院学报》2015,7(6):525-533

如何评估气象服务带来的综合经济效益,一直是人们关注的重点和难点.以投入产出表的分配系数、消耗系数和列昂捷夫逆矩阵为核心,提出了关联经济效益、间接经济效益和完全经济效益的概念和算法,并以深圳市2012年的气象服务为例对方法进行验证,得到了一系列富于启示意义的结论.如:1)由于产业经济系统内部的关联性,气象服务带来的关联经济效益、间接经济效益和完全经济效益值较大,应引起全社会的关注和重视;2)深圳市气象服务的投入与完全经济效益比值区间约为1:134.34~1:228.378,远大于以往研究1:30~1:51的结果;3)传统的气象服务对象如农林牧渔业、建筑业等带来服务经济效益偏低,未来应重视向研究与试验发展业,综合技术服务业,租赁和商务服务业,居民服务和其他服务业,信息传输、计算机服务和软件业等服务产业提供气象服务,提高气象服务给社会带来的综合经济效益.  相似文献   

2021年5月21日漾濞M_S 6.4地震前地震活动异常分析     

高琼  邓嘉美  陈佳 《地震地磁观测与研究》2021,42(5):51-57

2021年5月21日漾濞发生M_S 6.4地震,震前地震活动异常明显,中长期阶段云南地区3级地震活动水平较低,滇西北地区出现长达456天的4级地震平静;短临阶段震中区附近出现3—4级地震条带;临震阶段中小地震活动由外围地区开始向震中区迁移,震中区出现直接前震。  相似文献   

不同变形性质正轴圆柱投影和正轴圆锥投影间的直接变换     

李厚朴  边少锋 《测绘学报》2012,41(4):536-542

为避免不同变形性质正轴圆柱投影和正轴圆锥投影间传统间接变换繁琐的计算过程,利用子午线弧长、等量纬度和等面积纬度函数间变换的直接展开式,建立了相应投影坐标间的直接变换模型,无需计算大地纬度即可完成变换。本文导出公式均为含参考椭球第一偏心率的符号形式,可解决两类投影在不同参考椭球下的变换问题。算例分析表明与传统间接变换模型相比,本文建立的直接变换模型提高了计算效率和计算精度,可供实际使用。  相似文献