准晶体的构筑原理及微粒分数维结构模型   总被引：7，自引：1，他引：7  

彭志忠 《地球科学》1985,(4)

准晶体的原子构造中两个原理在起作用,即二十面体原理和黄金中值原理。二十面体原理是指大小相近的原子形成孤立的十二次配位体时,二十面体配位形式在能量上最有利。黄金中值原理是指在准晶体中原子的排列符合黄金中值律。这两个原理适用于由少量原子构成的体系,也适用于某些生物的结构。运用这两个原理于准晶体微粒,我们获得了最简单的准晶体结构模型。此模型可以解释Al-Mn准晶体的高分辨图的所有细节。此模型与Hiraga模型以及Bursill和彭菊琳模型都不相同。在此模型中Al_(12)Mn二十面体不是共棱的。这一模型具有分数维结构的待征,因此称之为准晶体的微粒分数维结构模型。  相似文献   

甘肃西部地区高放废物处置库场址预选调查   总被引：1，自引：0，他引：1  

刘林清  余运祥 《华东地质学院学报》1995,18(1):33-39

本文根据高放废物处置库场址选择的基本要求，对区域地质及深部构造特征、新构造运动及地震分布规律进行了调查，确定北山南带地区为稳定区。在稳定区内根据处置库有利围岩的出露情况，结合岩体工程地质特征分析，初步选出了４个以花岗岩为主体的场址预选区。经综合分析，认为在４个场址预选区中，以Ｉ号预选区的条件最优，其次是Ⅱ号预选区，再次是Ⅲ号和Ⅳ号预选区。场址区的最后确定尚待进一步调查和论证。  相似文献   

夜间气象能见度的测量研究   总被引：3，自引：0，他引：3  

胡江华  周建勋 《南京气象学院学报》1995,18(4):584-587

运用能见度理论和双止偏光能见度测定仪原理，讨论了夜间气象能见度的测量原理和一种新的测量方法，并完成了初步的野外对比试验，得出了比较结论。  相似文献   

氡气勘查地球化学技术的研究与应用--氡气地球化学特性、方法原理、异常模式   总被引：7，自引：1，他引：7  

贾国相  赵友方  姚锦其  黎绍杰 《矿产与地质》2005,19(1):60-65

从氧的地球化特性、氧气测量方法的原理、氧的地球化学晕的形成机理及氧气异常模式的确立等方面，阐述了氧气勘查地球化学技术在油气勘查应用研究中的概况。认为该技术在方法、原理及应用效果等方面的研究已日趋成熟，应用该项技术，在油气藏上方的土壤或岩石中，已查明氧气呈环状晕圈特征，并且，这一规律被反复得到证实和公认，可进一步在油气勘查领域推广应用。  相似文献   

桉树腐殖酸(HA)专用肥区域试验与配方的优选     

钱国钦 《福建地理》2007,(4)

采用随机区组设计,以等价投入的常规化肥为对照,开展专用肥多点施肥试验研究.通过专用肥对林木生长量、林相特征的影响分析,结果表明:与等价投入(肥料成本)的常规化肥相比,施用系列专用肥的林分生长量均显著或极显著地高于常规化肥处理,且叶片浓绿、树势强壮,施后19个月内,树高、胸径、材积分别提高了7.8%~51.8%、9.8%~53.0%和30%以上,叶片叶绿素含量提高26.3%~94.2%,叶面积指数提高41.0%~172.8%.经对HA桉树专用肥的增产性、适应性和稳定性的综合分析与评定,选出基肥专用的优化配方为:有机质≥30.0%、N P2O5 K2O≥6.0%(2.5-2.0-1.5)、腐殖酸总量≥8.0%,并加上适量的"绿滴"复合微生物菌剂(于施用时和基肥按每50 kg∶1 kg的量掺入);追肥专用的优化配方为:有机质≥20.0%、N P2O5 K2O≥20.0%(9-8-3)、腐殖酸总量≥6.0%.  相似文献   

Entropy‐based equation to assess hillslope sediment production     

José Carlos de Araújo 《地球表面变化过程与地形》2007,32(13):2005-2018

A new equation to assess hillslope sediment production, based on physical and probabilistic approaches, is presented. The equation, which allows the computation of the delivery ratio for every event, considers the physical variables of travel distance, stream power, settling velocity and gross erosion. The probability density function that arises from the new formulation is solved using the principle of maximum entropy. Based on data from five watersheds in both tropical and temperate zones, the new delivery parameter K_v is calibrated and associated with vegetation cover and conservation practice. The proposed equation is rationally based in relation to parameter K_v. The entropy‐based equation was applied to assess sediment yield in two other experimental watersheds, showing good predictability for the set (mean absolute error of 20·8%). No systematic error was found in the analysed data. The entropy‐based equation showed good predictability for long‐term sets of data and for high‐erosivity events, but did not perform well for the low‐erosivity ones. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Non‐linear system identification of the versatile‐typed structures by a novel signal processing technique     

Jian Zhang  Tadanobu Sato  Susumu Iai 《地震工程与结构动力学》2007,36(7):909-925

Non‐linear structural identification problems have raised considerable research efforts since decades, in which the Bouc–Wen model is generally utilized to simulate non‐linear structural constitutive characteristic. Support vector regression (SVR), a promising data processing method, is studied for versatile‐typed structural identification. First, a model selection strategy is utilized to determine the unknown power parameter of the Bouc–Wen model. Meanwhile, optimum SVR parameters are selected automatically, instead of tuning manually. Consequently, the non‐linear structural equation is rewritten in linear form, and is solved by the SVR technique. A five‐floor versatile‐type structure is studied to show the effectiveness of the proposed method, in which both power parameter known and unknown cases are investigated. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Prediction of the median IDA curve by employing a limited number of ground motion records     

Alireza Azarbakht  Matjaž Dolšek 《地震工程与结构动力学》2007,36(15):2401-2421

A methodology has been proposed which can be used to reduce the number of ground motion records needed for the reliable prediction of the median seismic response of structures by means of incremental dynamic analysis (IDA). This methodology is presently limited to predictions of the median IDA curve only. The reduction in the number of ground motion records needed to predict the median IDA curve is achieved by introducing a precedence list of ground motion records. The determination of such a list is an optimization problem, which is solved in the paper by means of (1) a genetic algorithm and (2) a proposed simple procedure. The seismic response of a simple, computationally non‐demanding structural model has been used as input data for the optimization problem. The presented example is a three‐storey‐reinforced concrete building, subjected to two sets of ground motion records, one a free‐field set and the other a near‐field set. It is shown that the median IDA curves can be predicted with acceptable accuracy by employing only four ground motion records instead of the 24 or 30 records, which are the total number of ground motion records for the free‐field and near‐field sets, respectively. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

地下储气库评价设计方法及应用     

杨树合  何书梅  季静  杨丽蓉 《新疆地质》2002,20(3):271-273

地下储气库对调节冬夏季节天然气供需矛盾，保障用户需求、优化集输系统功能有重要作用。在对地下储气库概念及原理进行阐述的基础上，提出了建立地下储气库应具备的首要条件，同时对地下储气库设计过程中应重点解决的回顾及指标设计进行了详细论述。通过建设实践，证实了文中提出的设计及评价方法的可靠性。  相似文献   

基于MEM1谱分析的水文时间序列隐含周期特性研究   总被引：13，自引：1，他引：13  

王栋  朱元甡 《水文》2002,22(2):19-23

水文时间序列的隐含周期(本文将简单周期、复合周期及近似周期等统称为隐含周期)的识别、判定是一个重要而又较为困难的问题,相对成熟和有效的做法是对其进行频谱分析。建立在最大熵原理(POME)基础之上的MEM1谱分析,克服了传统谱分析方法的诸多不足,具有频谱光滑、分辨率高等独特优势。为此,以黄河花园口(秦厂)测站年径流系列、月径流系列和年最大洪峰流量序列隐含周期特性的研究为例,探讨了MEM1谱分析在水文时间序列隐含周期特性中的应用。  相似文献