地下贯通工程测量方案的优化理论和方法   总被引：2，自引：0，他引：2  

冯仲科 《测绘学报》1996,25(4):303-308

地下贯通工程的控制测量导线多为加测陀累方位角的导线，本文讨论了贯通工程导线加测陀螺边的个数，位置，以及提高其可靠性，经济性的有关问题。  相似文献   

断陷湖盆隐蔽油藏预测及勘探的关键技术--高精度地震探测基础上的层序地层学研究   总被引：82，自引：6，他引：76  

李思田  潘元林等 《地球科学》2002,27(5):592-598

近十余年世界的我国隐蔽油藏勘探取得了巨大进展,其关键技术是高精度的三维地震及在此基础上的层序地层学研究,二者的结合已被油气产业部门当作勘探中的“权威性技术”。断陷湖盆在我国东部含油气资源的重要性居首位,控制层序形成演化的诸因素中,构造,古气候和在区域古地理格局中的位置对湖盆的类型和演化起着决定作用,需要按照断陷湖盆的沉积构造演化特征建立有预测功能的层序构成模式,在成熟的勘探区,重新建立等时层序地层格架,进行体系域精度的工业制图,阐明沉积体系的分布规律,使用高精度地球物理技术对圈闭定位,并对构造坡折带和低位域扇体给予重点注意,用这种技术方法指导隐蔽油气藏的勘探,已经并必将有许多重要发现。  相似文献   

Pre‐ and post‐test mathematical modelling of a plan‐asymmetric reinforced concrete frame building     

Peter Fajfar  Matja Dol&#x;ek  Damjan Maru&#x;i&#x;  Aurel Stratan 《地震工程与结构动力学》2006,35(11):1359-1379

Pre‐ and post‐test analyses of the structural response of a three‐storey asymmetric reinforced concrete frame building were performed, aimed at supporting test preparation and performance as well as studying mathematical modelling. The building was designed for gravity loads only. Full‐scale pseudo‐dynamic tests were performed in the ELSA laboratory in Ispra. In the paper the results of initial parametric studies, of the blind pre‐test predictions, and of the post‐test analysis are summarized. In all studies a simple mathematical model, with one‐component member models with concentrated plasticity was employed. The pre‐test analyses were performed using the CANNY program. After the test results became available, the mathematical model was improved using an approach based on a displacement‐controlled analysis. Basically, the same mathematical model was used as in pre‐test analyses, except that the values of some of the parameters were changed. The OpenSees program was employed. Fair agreement between the test and numerical results was obtained. The results prove that relatively simple mathematical models are able to adequately simulate the detailed seismic response of reinforced concrete frame structures to a known ground motion, provided that the input parameters are properly determined. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Damping characteristics of friction damped braced frame and its effectiveness in the mega-sub controlled structure system   总被引：10，自引：1，他引：10  

连业达  张询安 《地震工程与工程振动(英文版)》2007,6(2):171-181

Based on energy dissipation and structural control principle, a new structural configuration, called the mega- sub controlled structure (MSCS) with friction damped braces (FDBs), is first presented. Meanwhile, to calculate the damping coefficient in the slipping state a new analytical method is proposed. The damping characteristics of one-storey friction damped braced frame (FDBF) are investigated, and the influence of the structural parameters on the energy dissipation and the practical engineering design are discussed. The nonlinear dynamic equations and the analytical model of the MSCS with FDBs are established. Three building structures with different structural configurations, which were designed with reference to the conventional mega-sub structures such as used in Tokyo City Hall, are comparatively investigated. The results illustrate that the structure presented in the paper has excellent dynamic properties and satisfactory control effectiveness.  相似文献   

云南茶树林铅锌矿电磁波找矿效果     

李本茂  张学良  史家良  普建林 《云南地质》2007,26(2):257-263

茶树林铅锌矿，过去认为震旦系赋矿，钻探验证未见矿。本次利用物探方法实施深部探矿。依据物探异常，结合地质规律综合分析，认为是构造控矿。布置验证坑道，沿断裂破碎带发现新的厚大、品位高铅锌矿体，收到良好的找矿效果。  相似文献   

夯扩桩沉管控制贯入度计算法     

周武阶 《地质与勘探》1998,34(5):53-55

通过改造格尔谢万诺夫打桩公式,提供了夯扩桩沉管控制贯入度计算表达式,在此 ,介绍了沉积控制贯入度在夯扩桩设计和施工中的用途,并举例验证。  相似文献   

水泥厂球磨机基础切割拆除控制爆破          下载免费PDF全文

黄常波  陈建平 《探矿工程》1998,(6):52-54

介绍了基础切割拆除爆破的实践和经验。同时成功地应用了非电毫秒导爆管雷管孔外多级接力扩大雷管起爆段数的方法。  相似文献   

Econometric analysis of the ship demolition market     

Sabine Knapp  Shashi N. Kumar  Anna Bobo Remijn   《Marine Policy》2008,32(6):1023-1036

The topic of ship recycling has obtained considerable attention during the last two decades for a variety of reasons with the likelihood of the adoption of a new international convention under the auspices of the International Maritime Organization (IMO). This study applies econometric modeling to a unique data set to provide insight into the dynamics of the ship recycling market. The data set contains information on 51,112 ships over 100 gt and includes 748,621 events over a period of 29 years. The analysis confirms a negative relationship of earnings and a positive relationship of scrap prices for all locations while Bangladesh seems to be more sensitive to changes in earnings than the other locations and more likely demolishes larger and older vessels. The results for flag and ownership vary across scrapping locations with Malta and Cyprus indicating potential importance from a registry perspective. The overall safety profile of a vessel seems to be less important towards the probability of a ship being scrapped. Possible implementation of the convention at EU level will mostly likely affect Turkey while non-ratification of one of the major flags will most likely affect China or Bangladesh.  相似文献   

江苏近岸紫菜养殖筏架区定生绿藻群落结构及其受控因素   总被引：3，自引：1，他引：2  

李艳  肖洁  丁兰平  王宗灵  宋伟  方松  范士亮  李瑞香  张学雷 《海洋学报(英文版)》2015,34(8):93-99

基于2010年10月至2011年4月对苏北紫菜养殖筏架区定生绿藻及环境因素调查数据,分析研究了紫菜筏架上定生绿藻种群结构和数量变化及重要环境因子对其的影响并估算了调查区绿藻总生物量.结果表明,筏架上定生绿藻种类有浒苔(Ulva prolifera)、盒管藻(Capsosiphon groenlandicus)、缘管浒苔(Ulva linza)、肠浒苔(Ulva intestinalis)、条浒苔(Ulva clathrata)和扁浒苔(Ulva compressa).绿藻生物量变化呈倒抛物线型,4月份为主高峰14898吨,11月份为次高峰2034吨,2月份最低,仅为729吨,3-4月份绿藻几乎呈暴发性增长.种类多样性随季节变化有很大差异,养殖筏架刚入海的9、10月份,绿藻种类丰富,生物多样性高;12月至笠年2月,尽管生物量很低,但仍是多种并存;3-4月份随着生物量的猛增,种类多样性降至最低,盒管藻优势地位明显,生物量比例最大能到80%,浒苔比例呈指数增长,达20%～40%.水温对绿藻生物量及种类演替有直接调控作用,在水温< 10℃时,绿藻即能快速生长;而盐度作用不明显.开展紫菜筏架上定生绿藻群落动态变化及其生物量的估算,为追溯南黄海大规模绿潮发源地提供佐证,为绿潮预防和治理提供基础数据支撑.  相似文献   

带有小数补偿的低频数控振荡器及其基于FPGA的实现     

朱峰  李孝辉  王国永 《时间频率学报》2011,34(2)

在分析数控振荡器（NCO）工作原理的基础上,以低频信号为例,研究了影响NCO性能的几个因素。结合杂散特性,着重讨论了频率控制字误差对输出频率带来的影响,提出在相位累加器中加入小数部分补偿,以使降低信号频率门限值和提高输出的准确性。最后采用FPGA（现场可编程门阵列）实现了带有小数补偿的NCO,在兼顾硬件资源的同时优化了系统性能,另外通过仿真验证了这种方法的可行性。  相似文献