Proof of the equivalence of Tanizawa–Berkvens’ and Cointe–van Daalen's formulations for the time derivative of the velocity potential for non-linear potential flow solvers     

《Applied Ocean Research》2017

Dealing with freely-floating bodies in the framework of non-linear potential flow theory may require solving Laplace's equation for the time derivative of the velocity potential. At present, there are two competing formulations for the body boundary condition. The first one was derived by Cointe [1] in 2D. It was later extended to 3D by van Daalen [2]. The second formulation was derived by Tanizawa [3] in 2D. It was extended to 3D by Berkvens [4]. In this paper, a proof is given that the Cointe–van Daalen's and the Tanizawa–Berkvens’ formulations are equivalent. It leads to a simplified version of Cointe–van Daalen's formulation. The formulation is validated against the analytical solution for a moving sphere in an unbounded water domain.  相似文献   

新疆一次罕见的暖区暴雨过程特征分析     

阿不力米提江.阿布力克木  汤浩  张俊兰 《沙漠与绿洲气象(新疆气象)》2019,13(6):1-12

2018年7月31日新疆出现了一次罕见的暴雨过程,最大暴雨中心位于新疆东部哈密市,哈密市伊州区沁城乡小堡村过程累计雨量115.5 mm,连续2个时次小时雨强29.2 mm。对比哈密市建站以来6个国家气象站历年资料发现,此次暴雨特征与以往冷锋暴雨明显不同,暴雨降水时段更为集中,强度比冷锋暴雨更强,暴雨云团为典型的中尺度云团,范围小、呈块状。由于500 h Pa西太平洋副热带高压偏西偏北,高空无低值系统和冷空气入侵,哈密市主要受西太平洋副热带高压外围偏南暖湿气流的影响,此次暴雨结合了南方副热带高压型和偏南风风速辐合型暖区暴雨的典型特征,具有暖区暴雨的热力结构和风场配置,是一次罕见的暖区暴雨过程。暴雨区偏南风风速辐合和暴雨区山区地形的抬升效应是本次暴雨重要的触发机制,700 hPa孟加拉湾和日本海南部两支水汽在华北平原汇合沿东南输送路径至暴雨区且有强烈水汽辐合。暴雨发生在云顶亮温(TBB)等值线密集区梯度最大处,越接近TBB低值中心梯度处的暴雨强度越强。  相似文献   

Feeling Slow Food: Visceral fieldwork and empathetic research relations in the alternative food movement     

Allison Hayes-Conroy 《Geoforum》2010,41(5):734-742

This paper details the author’s experiments with accessing the visceral realm in research on the food-based social movement, Slow Food (SF). “Visceral” is defined as the bodily realm where feelings, sensations, moods and so on are experienced. Fieldwork methods aimed at participatory co-creation of data through verbal communications in the form of in-depth conversations and group discussions, as well as non-verbal communications in the form of “intentionally designed experiences” and other forms of sensory involvement. Communications centered on understanding how foods and food-based settings elicit feelings and sensations that move and power bodies differently, and specifically how SF guides bodies to be affected by specific foods and environments. The paper details how data were created and recorded, specifically exploring how sensory-based research events were translated to data through the creation of imagined bodily empathies. The paper also discusses the emergence of change-oriented communications that pushed for transformation in SF’s (in)attention to visceral differences, thus demonstrating how visceral research can challenge researchers and participants to critically reflect upon, and perhaps transform, how their own bodies feel (and respond to) the world.  相似文献   

香格里拉红牛铜多金属矿成矿模式及深部找矿     

邹顺坤  张志平 《云南地质》2010,29(3):299-302,244

红牛矿属印支晚期义敦岛弧带南段、中甸弧主弧期远程熔体(岩浆)—溶液改造型矽卡岩矿床,赋存于上三叠统曲嘎寺组第二段地层中。除典型矽卡岩铜矿床特征外,出现成矿温度较高的辉钼矿,推测矿区深部应发育含矿性较好的中酸性侵入体,具有寻找大—超大型矽卡岩—斑岩复合型铜钼多金属矿床的找矿前景。  相似文献   

保山市清水河铜铅锌多金属矿外围找矿新思路     

何志魁  苏兰 《云南地质》2010,29(3):307-310

工作区1∶5万土壤化探Cu、Pb、Zn、Ag、Au等元素异常发育,重力梯度带也显示存在中型Cu、Pb、Zn硫化物中型矿床的可能。研究认为:背斜核地(双脉地带)有较大背景。  相似文献   

人体舒适度预报方法研究   总被引：13，自引：5，他引：13  

石春娥  王兴荣等 《气象科学》2001,21(3):363-368

经过人群调查得出适合于江淮地区人体舒适度指数公式及预报指标，综合利用T106数值预报产品和地面常规资料，采用MOS预报的方法和天气气候统计方法预报出气温、风速、日照等与舒适度指数有关的气象要素，研制了合肥市人体舒适度预报系统，该系统具有明显的地方特色，和客观实用，易于操作等特点。  相似文献   

The effect of Holocene temperature fluctuations on the evolution and ecology of Neotoma (woodrats) in Idaho and northwestern Utah     

Felisa A Smith  Julio L Betancourt 《Quaternary Research》2003,59(2):160-171

Animals respond to climatic change by adapting or by altering distributional patterns. How an animal responds is influenced by where it is positioned within its geographic range; the probability of extirpation is increased near range boundaries. Here, we examine the impact of Holocene climatic fluctuations on a small mammalian herbivore, the bushy-tailed woodrat (Neotoma cinerea), at five locations within south central Idaho and northwestern Utah. Previous work demonstrated that woodrats adapt to temperature shifts by altering body size. We focus here on the relationship between body mass, temperature, and location within the geographic range. Body mass is estimated by measuring fossil fecal pellets, a technique validated in earlier work. Overall, we find the predicted phenotypic response to climate change: animals were larger during cold periods, and smaller during warmer episodes. However, we also identify several time periods when changes in environmental temperature exceeded the adaptive flexibility of N. cinerea. A smaller-bodied species, the desert woodrat (N. lepida) apparently invaded lower elevation sites during the mid-Holocene, despite being behaviorally and physically subordinate to N. cinerea. Analysis of contemporary patterns of body size and thermal tolerances for both woodrat species suggests this was because of the greater heat tolerance of N. lepida. The robust spatial relationship between contemporary body size and ambient temperature is used as a proxy to reconstruct local climate during the Holocene.  相似文献   

1998年1月10日张北-尚义6.2级地震前昌平地震台应变资料的异常变化分析          下载免费PDF全文

王勇  刘福生  张国红  张学政 《地震工程学报》1999,21(3):15

分析了昌平地震台体应变、线应变及差应变等观测资料在１９９８ 年１ 月１０日张北尚义６ ．２ 级地震前的异常变化．结果表明：该次地震前昌平台的应变观测资料出现了明显的趋势异常;体应变的异常时间与震级有较好的相关性;差应变资料显示了短临异常;由线应变资料计算的主应变方向在地震前逐渐向震中偏转; Ｍ２ 波潮汐因子也出现了明显的异常变化  相似文献   

The Key Technical Points and Main Characteristics of the New National Standard of Magnitude     

Liu Ruifeng  Wang Liyan 《中国地震研究》2018,32(3):301-314

The New Magnitude National Standard of General Rules for Earthquake Magnitude( GB17740-2017) is the state mandatory standard. It was released on May 12,2017,by the General Administration of Quality Supervision,Inspection and Quarantine of the Peoples Republic of China and the Standardization Administration of the Peoples Republic of China. This paper introduces the necessity of revising the national standard of magnitude,and the main contents,technical points and primary features of the new national standard of magnitude,so that it can be applied better in practice.  相似文献   

3D <Emphasis Type="Italic">v</Emphasis><Subscript>P</Subscript> and <Emphasis Type="Italic">v</Emphasis><Subscript>S</Subscript> models of southeastern margin of the Tibetan plateau from joint inversion of body-wave arrival times and surface-wave dispersion data          下载免费PDF全文

Lina Gao  Haijiang Zhang  Huajian Yao  Hui Huang 《地震科学（英文版）》2017,30(1):17-32

A new 3D velocity model of the crust and upper mantle in the southeastern (SE) margin of the Tibetan plateau was obtained by joint inversion of body- and surface-wave data. For the body-wave data, we used 7190 events recorded by 102 stations in the SE margin of the Tibetan plateau. The surface-wave data consist of Rayleigh wave phase velocity dispersion curves obtained from ambient noise cross-correlation analysis recorded by a dense array in the SE margin of the Tibetan plateau. The joint inversion clearly improves the v _S model because it is constrained by both data types. The results show that at around 10 km depth there are two low-velocity anomalies embedded within three high-velocity bodies along the Longmenshan fault system. These high-velocity bodies correspond well with the Precambrian massifs, and the two located to the northeast of 2013 M _S 7.0 Lushan earthquake are associated with high fault slip areas during the 2008 Wenchuan earthquake. The aftershock gap between 2013 Lushan earthquake and 2008 Wenchuan earthquake is associated with low-velocity anomalies, which also acts as a barrier zone for ruptures of two earthquakes. Generally large earthquakes (M ≥ 5) in the region occurring from 2008 to 2015 are located around the high-velocity zones, indicating that they may act as asperities for these large earthquakes. Joint inversion results also clearly show that there exist low-velocity or weak zones in the mid-lower crust, which are not evenly distributed beneath the SE margin of Tibetan plateau.  相似文献