杭州西湖总磷动态变化预测

建立了西湖污染物分析和浓度变化的水质对流扩散模型,并利用该模型对西湖水体引水后７ｄ内总磷浓度的变化进行了预测,然后对预测结果作了较为详细的分析。     

局部倾角滤波和预测反演联合分离绕射波

地震绕射波源于介质非连续性,从地震记录中将绕射波分离出来并进行成像,其结果对研究诸如碳酸盐岩缝洞储层这类复杂非均质储层具有重要意义.对炮集记录进行平面波分解,在地层倾角不大的假设下,反射波和绕射波同相轴在平面波分解剖面上存在较大的倾角差异.基于此,我们提出分步进行绕射波分离的方法:(1)利用局部倾角滤波方法将绕射波的较大倾角信息成分分离出来,此时,余下的部分包含有反射波和残留的低倾角绕射波信息;(2)利用频率-空间域预测反演方法从上述含有反射波和残留的低倾角绕射波信息中分离出残留绕射波成分;(3)将两次分离的绕射波信息相加得到最终的绕射波估计.用该方法能够得到相对完整的绕射波信息,有效地克服了靠单一的倾角差异进行绕射波分离时明显损失低倾角信息,从而影响绕射波成像结果横向分辨率这一问题.理论与实际资料试算验证了该方法的有效性.     

Copula-based identification of the non-stationarity of the relation between runoff and sediment load

It is important to identify the non-stationarity in the relation between runoff and sediment load under the backdrop of the changing environment. This relation helps to further understand the mechanisms of runoff and sediment yield. A copula-based method was used to detect possible change points in the relation between runoff and sediment load in the Wei River Basin (WRB), China, where soil erosion is a very severe issue. The modified Mann-Kendall trend test method was applied to obtain the trends of runoff and sediment load spanning 1960–2010 at monthly and annual timescales. Finally, the causes of the identified non-stationarity of the relation between runoff and sediment load were roughly analyzed from the perspective of climate change and human activities. Results indicated that:(1) the runoff and sediment load in the Jinghe and Wei rivers were generally characterized by noticeably decreasing trends at both monthly and annual timescales;(2) both the Jinghe and Wei rivers had a common change point (2002), implying that the stationarity of the relation between runoff and sediment load in the Jinghe and Wei River was invalid; (3) human activities including increasing water consumption and growing application of soil conservation practices are dominant factors resulting in non-stationarity in the rela-tion between runoff and sediment load in the WRB. This study provides a new idea for identifying the non-stationarity of multivariate relation in the hydro-meteorological field under the background of the changing environment.     

2014年8月云南鲁甸MS 6.5地震典型地表破裂特征

北京时间2014年8月3日16时30分,云南省鲁甸县发生了M_S 6.5地震,本次地震的发震构造为包谷垴-小河断裂。野外调查发现,王家坡不稳定斜坡上的地表破裂在整个破裂带中比较具有代表性,其地表破裂带整体走向N45°W-N50°W,并且由剪切破裂、张剪切破裂、压剪切破裂、张性破裂以及鼓包等典型地表破裂组成。其中左、右地表破裂边界与发震断层的出露位置一致,由断层错动造成;而部分地表破裂与断层的位置不重合,其成因分为2种,一种是发震断层导致的一些次级地表破裂,另一种是地震引发的滑坡后缘破裂。地表破裂类型和基本组合特征显示出王家坡潜在不稳定斜坡上的地表破裂带具有左旋走滑的性质。     

Quantitative analysis of the impact of droughts and floods on internal wars in China over the last 500 years

Although many large-N quantitative studies have evidenced the adverse effects of climatic extremes on social stability in China during the historical period, most of them rely on temperature and precipitation as major explanatory variables, while the influence of floods and droughts on social crises is rarely measured. Furthermore, a comparison of the climate-society nexus among different geographic regions and at different temporal scales is missing in those studies. To address this knowledge gap,this study examines quantitatively the influence of floods and droughts on internal wars in three agro-ecological(rice, wheat,and pastoral) regions in China in AD1470–1911. Poisson regression and wavelet transform coherence analyses are applied to allow for the non-linear and non-stationary nature of the climate-war nexus. Results show that floods and droughts are significant in driving internal wars in historical China, but are characterized by strong regional variation. In the rice region, floods trigger internal wars at the inter-annual and multi-decadal time scales. In the wheat region, both floods and droughts cause internal wars at the inter-annual and multi-decadal time scales. In the pastoral region, internal wars are associated with floods only at the multi-decadal time scale. In addition, the multi-decadal coherence between hydro-climatic extremes and internal wars in all three of the agro-ecological regions is only significant in periods in which population density is increasing or the upper limit of regional carrying capacity is being reached. The above results imply that the climate-war nexus is mediated by regional geographic factors such as physical environmental setting and population pressure. Hence, we encourage researchers who study the historical human-climate relationship to boil down data according to geographic regions in the course of statistical analysis and to examine each region individually in follow-up studies.     

Effects of different spatial distributions of physical soil crusts on runoff and erosion on the Loess Plateau in China

The response of runoff and erosion to soil crusts has been extensively investigated in recent decades. However, there have been few attempts to look at the effects of spatial configuration of different soil crusts on erosion processes. Here we investigated the effects of different spatial distributions of physical soil crusts on runoff and erosion in the semi‐arid Loess Plateau region. Soil boxes (1.5 m long × 0.2 m wide) were set to a slope of 17.6% (10°) and simulated rainfall of 120 mm h^?1 (60 minutes). The runoff generation and erosion rates were determined for three crust area ratios (depositional crust for 20%, 33%, and 50% of the total slope) and five spatial distribution patterns (depositional crust on the lower, lower‐middle, middle, mid‐upper, and upper slope) of soil crusts. The reduction in sediment loss (‘sediment reduction’) was calculated to evaluate the effects of different spatial distributions of soil crusts on erosion. Sediment yield was influenced by the area ratio and spatial position of different soil crusts. The runoff rate reached a steady state after an initial trend of unsteadily increasing with increasing rainfall duration. Sediment yield was controlled by detachment limitation and then transport limitation under rainfall. The shifting time of erosion from a transport to detachment‐limiting regime decreased with increasing area of depositional crust. No significant differences were observed in the total runoff among treatments, while the total sediment yield varied under different spatial distributions. At the same area ratio, total sediment yield was the largest when the depositional crust was on the upper slope, and it was smallest when the crust was deposited on the lower slope. The sediment reduction of structural crust (42.5–66.5%) was greater than that of depositional crust (16.7–34.3%). These results provide a mechanistic understanding of how different spatial distributions of soil crusts affect runoff and sediment production. Copyright © 2017 John Wiley & Sons, Ltd.     

Design of dampers for structures based on optimal control theory

The aim of this paper was to propose a design guideline for using visco‐elastic dampers for the control of building structures subjected to earthquake loading as well as suspension roof structures subjected to wind loading. The active control algorithm was used to calculate the control forces. Based on the single‐mode approach the control forces were transformed to the forces which visco‐elastic dampers can provide. Application of the method to the design of the building structure with passive damping devices in the bracing system and to the suspension roof with dampers was studied. Through the application of optimal control theory a systematic design procedure to implement dampers in structures is proposed. Copyright © 2000 John Wiley & Sons, Ltd.     

基于SuperMap IS.NET的西安市基础地理信息查询系统设计与实现

随着城市规模的不断扩大,基础地理信息呈海量化、多元化、跨时空等特点。管理任务日趋繁重,建立现代化的基础地理信息综合查询系统迫在眉睫。本文探讨了基于SuperMap IS.NET网络GIS平台建立的西安市基础地理信息综合查询系统,并就该系统的数据模型、系统架构、系统设计目标、功能设计和关键技术进行了介绍。     

新疆北部弧-盆转化体系下铁氧化物-铜-金矿床的流体演化特征:来自卤族元素和稀有气体同位素的证据

东准噶尔北缘和东天山雅满苏带是中国新疆北部地区两个重要的晚古生代铁氧化物-铜-金矿化潜力区,以老山口、乔夏哈拉和黑尖山矿床作为典型矿床代表。研究表明两区域的铁氧化物-铜-金矿床均产出于盆地闭合的弧盆转化体系下,且具有明显的铁、铜-金两阶段矿化。卤族元素和稀有气体同位素作为可靠的流体示踪剂,被应用于探究这一特定构造环境下的铁氧化物-铜-金矿床的流体演化和矿床成因。结果显示老山口、乔夏哈拉和黑尖山矿床的成矿流体具有明显的混合流体端员特征:(1)岩浆流体端员,主要参与黑尖山矿床磁铁矿阶段,I/Cl、Br/Cl和⁴⁰Ar/³⁶Ar比值分别为(16.3~18.0)×10^-6、(1.03~1.06)×10^-3和352~437;(2)海水表源蒸发成因盐卤水端员,主要参与老山口矿床铜-金矿化阶段,I/Cl、Br/Cl和⁴⁰Ar/³⁶Ar比值分别为(77.1~87.7)×10^-6、(1.53~1.80)×10^-3和672~883;(3)蒸发岩溶解或者深度水-岩反应成因的盐卤水/沉积岩地层水端员,主要参与到老山口、乔夏哈拉矿床的磁铁矿阶段以及黑尖山、乔夏哈拉矿床的铜-金矿化阶段,综合I/Cl、Br/Cl和⁴⁰Ar/³⁶Ar比值分别为(477~26 301)×10^-6、(0.39~1.28)×10^-3和288~510。明显的多阶段矿化和铜-金矿化阶段以非岩浆富Ca高盐度卤水为主的特征与世界范围内的IOCG型矿床极为相似,表明新疆北部的铁氧化物-铜-金矿床应为IOCG型矿床。     

斑岩型和浅成低温热液型矿床成矿流体与找矿预测研究:以华南若干典型矿床为例

斑岩型和浅成低温热液型矿床是全球铜、钼、金、银的主要来源之一,具有重要经济价值。这两类矿床之间通常存在紧密的时空关系,对其成矿流体性质和演化的解剖不仅有利于探究金属沉淀机制,也有助于揭示两者之间的内在成因联系。本文在综述国内外重要研究前沿基础上,以中国华南富家坞斑岩型铜钼(金)矿、桐村斑岩钼矿,以及邱村和安村浅成低温热液金矿为例,系统总结了斑岩型和浅成低温热液型矿床流体特征、演化规律和金属沉淀机制、探讨了从斑岩型到浅成低温热液型流体演化的“气相迁移”模型,并以福建紫金山铜金矿床为例,介绍了应用流体填图进行找矿预测的实例。