水稻田甲烷的减排方法研究及评价   总被引：26，自引：1，他引：25  

李晶  王明星  陈德章 《大气科学》1998,22(3):354-362

通过对稻田甲烷排放多年的野外实验观测和对稻田甲烷排放控制因子的研究,总结出减少稻田甲烷排放的主要方法,对各种减排方法的减排效果和经济效益做了研究,并利用层次分析法对各种减排方法做了进一步的评价分析。现有的稻田甲烷减排方法主要有其他肥料代替传统的有机肥、种植低甲烷排放的水稻品种,以及稻田的灌水管理。适合中国国情的方法主要有杂交稻替代常规稻,沼渣肥替代纯有机肥。杂交稻替代常规稻的经济效益很显著,减少甲烷排放的同时能增加水稻的产量。沼渣肥替代有机肥的减排效果较好,社会效益和环境效益明显优于杂交稻替代常规稻。  相似文献   

普通栽培稻×小粒野稻F_1酯酶同工酶研究     

陈景  张建中  刘康平 《广东海洋大学学报》1998,(1)

用二倍体普通栽培稻和异源四倍体小粒野稻及其杂种一代（F1）进行酯酶同工酶测定和主要性状的田间表证。结果表明：普通栽培稻与小粒野生稻由于亲缘关系较远,其遗传基础差异很大,从而致使两者的酯酶同工酶谐相差也很大。两者杂交的F1,集中显示出双亲的所有酶带。F1的酶带是由于双亲互补的多个结构基因通过一系列调控机制而表达的结果。  相似文献   

INFLUENCE OF TIBETAN PLATEAU ON AIR-SEA INTERACTION OVER TROPICAL PACIFIC IN OCEAN-ATMOSPHERIC COUPLED SYSTEM     

吴爱明  倪允琪 《Acta Meteorologica Sinica》1998,(3)

A hybrid coupled ocean-atmosphere model is designed,which consists of a global atmosphericgeneral circulation model(L9R15 AGCM)and a simple ocean model(ZC ocean model over tropicalPacific).Using the model,experimental predictions are performed for the 1986/87 El Nino eventand the 1988/89 La Nina event with and without the Tibetan Plateau respectively(called TPFORC and NTP FORC hereinafter).It is found as follows:(1)The coupled system cansuccessfully predict the El Nino or La Nina event even if the Tibetan Plateau orography is notincluded in the model.The patterns of SSTA and wind anomalies in the model without the TibetanPlateau are similar to those with the Tibetan Plateau,which further verifies the fact that ENSOprocess is mainly caused by the air-sea interaction in tropical Pacific.(2)However.the existenceof the Tibetan Plateau exerts its influences on the intensity and duration of El Nino(or La Nina).It is unfavorable to the development and maintenance of westerly anomalies,so to some extent,restrains the development of El Nino,but favors the development of La Nina.(3)Effects of theTibetan Plateau orography on the wind anomalies in the coupled system are different from those inuncoupled AGCM simulation.  相似文献   

基于面向对象知识表达的空间推理决策及应用   总被引：7，自引：0，他引：7  

沙宗尧  边馥苓 《遥感学报》2004,8(2):165-171

提出了一种基于面向对象知识表达的空间推理决策方法 ,该方法扩展了常规的GIS空间分析功能 ,使其建立在GIS空间分析与领域知识基础上。认为GIS空间分析与领域知识利用的结合需要建立统一的知识表达概念模型 ,通过将常规决策知识设计为决策知识类 ,将决策事实作为事实知识类处理 ,并由知识类的消息机制进行内部通讯 ,实现空间推理决策的智能化。在进行领域知识分析与知识分类的基础上 ,给出了领域知识类的层次结构组织图和知识类定义以及决策知识及事实知识的面向对象表达 ,最后给出了空间知识类的形成及空间推理决策过程。方法的实用性在实践中得到验证  相似文献   

应用单纯形-模拟退火混合算法估计河流水质参数   总被引：3，自引：0，他引：3       下载免费PDF全文

郭建青  李彦  王洪胜  马健 《水科学进展》2004,15(6):765-769

将由单纯形法(SM)与模拟退火(SA)两种算法构成的混合算法(SMSA),应用于求解分析瞬时投放示踪剂情况下的一维河流水团示踪试验数据,估计河流水质参数的函数优化问题。分别就不同的降温指数、内循环次数与新状态产生函数中的扰动系数等算法控制参数对混合算法和改进模拟退火法的收敛速度的影响,进行了数值实验。结果表明,SMSA混合优化算法对于求解估计河流水质参数的函数优化问题是非常有效的。在实验条件下,与单一具有记忆功能的改进模拟退火法的水质参数计算结果相比较,SMSA混合算法具有:①混合算法的收敛速度明显优于改进模拟退火法;②降温指数和内循环次数对SMSA混合算法的收敛速度影响非常微弱;③新状态产生函数中的随机扰动幅度大小对算法收敛速度具有较为明显的影响等特点。  相似文献   

A Hybrid Neuro-Fuzzy Model for Mineral Potential Mapping   总被引：5，自引：0，他引：5  

Alok Porwal  E. J. M. Carranza  M. Hale 《Mathematical Geology》2004,36(7):803-826

A GIS-based hybrid neuro-fuzzy approach to mineral potential mapping implements a Takagi–Sugeno type fuzzy inference system in a four-layered feed-forward adaptive neural network. In this approach, each unique combination of predictor patterns is considered a feature vector whose components are derived by knowledge-based ordinal encoding of the constituent predictor patterns. A subset of feature vectors with a known output target vector (i.e., unique conditions known to be associated with either a mineralized or a barren location), extracted from a set of all feature vectors, is used for the training of an adaptive neuro-fuzzy inference system. Training involves iterative adjustment of parameters of the adaptive neuro-fuzzy inference system using a hybrid learning procedure for mapping each training vector to its output target vector with minimum sum of squared error. The trained adaptive neuro-fuzzy inference system is used to process all feature vectors. The output for each feature vector is a value that indicates the extent to which a feature vector belongs to the mineralized class or the barren class. These values are used to generate a favorability map. The procedure is applied to regional-scale base metal potential mapping in a study area located in the Aravalli metallogenic province (western India). The adaptive neuro-fuzzy inference system demarcates high favorability zones occupying 9.75% of the study area and identifies 96% of the known base metal deposits. This result is significant both in terms of reduction in search area and the percentage of deposits identified.  相似文献   

PART I: Theoretical Site Response Estimation for Microzoning Purposes     

P. Triantafyllidis  P. Suhadolc  P. M. Hatzidimitriou  A. Anastasiadis  N. Theodulidis 《Pure and Applied Geophysics》2004,161(5-6):1185-1203

— We estimate the theoretical site response along seven cross sections located in the city of Thessaloniki (Greece). For this purpose the 2-D structural models used are based on the known geometry and the dynamic soil properties derived from borehole measurements and other geophysical techniques. Several double-couple sources have been employed to generate the seismic wavefield, and a hybrid method that combines the modal summation with finite differences, has been deployed to produce synthetic accelerograms to a maximum frequency of 6 Hz for all components of motion. The ratios between the response spectra of signals derived for the 2-D local model and the corresponding spectra of signals derived for the 1-D bedrock reference model at the same site, allow us to estimate the site response due to lateral heterogeneities. We interpret the results in terms of both geological and geometrical features of the models and of the characteristics of the wave propagation. The cases discussed confirm that the geometry and depth of the rock basement, along with the impedance contrast, are responsible for ground amplification phenomena such as edge effects and generation and entrapment of local surface waves. Our analysis also confirms that the peak ground acceleration is not well correlated with damage and that a substantially better estimator for possible damage is the spectral amplification.  相似文献   

Analysis and Representation of Changes in Change Detection     

SUIHaigang  LIDeren 《地球空间信息科学学报》2002,5(2):13-16

In this paper,factors lead to changes ande what changes should be considered are firstly discussed.then changes to be represented by set theory is given.Twelve basic change types are described in detail.At last the paper points out that the change between geoobjects and pixels in images is not all corresponging and it causes the difficulty of accurate and robust change detection techniques.  相似文献   

3D Hybrid Ray-FD and DWN-FD Seismic Modeling for Simple Models Containing Complex Local Structures     

Ivo  Opršal  Johana  Brokešová  Donat  Fäh  Domenico  Giardini 《Studia Geophysica et Geodaetica》2002,46(4):711-730

Hybrid approaches find broad applications wherever all-in-one modelling of source, path, and site effects is too expensive. Our new 3D hybrid approach allows to compute the seismic wavefield in elastic isotropic models containing a complex local structure embedded in a large, but considerably simpler, regional structure. The hybrid modelling is realized in two successive steps.In the 1^st step, the ray or discrete wave number (DWN) method is used to compute the seismic wavefield due to the source and simple regional structure. The complex local structure is not present. Thus, the excitation contains the source and regional path effects. The time history of this wavefield (excitation), recorded at the points of so called excitation box, is stored on a disk. The excitation box envelopes a small portion of a computational domain.The 2^nd step of the hybrid method, now containing the complex local structure, is computed by finite differences (FD) inside the excitation box and its close vicinity. The excitation from the 1^st step is now used to inject the 1^st step wavefield into the 2^nd step computation. After that, the hybrid combination of the 1^st and 2^nd steps contains the source, regional path, and local structure effects at reasonably lower computational costs than in case of all-in-one modelling.The 3D ray-FD method is tested on models in which the locally complex structure is the well-known Volvi lake basin, embedded in various 1D structures. The wavefield is excited by the point source situated outside the basin. Although the structure outside the excitation box may be less dimensional (2D, 1D, homogeneous), the whole problem is actually 3D due to the 3D features of the structure inside the excitation box, 3D shape of the excitation box, and arbitrary source — excitation-box configuration. Simple (1D) structures outside the excitation box allow for comparison with the alternative hybrid DWN-FD results. However the ray method is suitable for computation of 3D regional structures outside the excitation box. The results from both approaches show a very good agreement for realistic crustal and local structural models.  相似文献   

Multiobjective optimal FLC driven hybrid mass damper system for torsionally coupled,seismically excited structures     

A. S. Ahlawat  A. Ramaswamy 《地震工程与结构动力学》2002,31(12):2121-2139

In most of the research work on structural vibration control only two‐dimensional plane structural modelling has been considered, although only a few practical building structures can be modelled as planar structures. Therefore, these methods are not directly applicable to the majority of the practical building structures. This paper discusses the design of a multiobjective optimal fuzzy logic controller (FLC) driven hybrid mass damper (HMD) system for seismically excited torsionally coupled building structures. Floor acceleration and velocity information have been used as feedback to the fuzzy logic controller. A three branch tournament Genetic Algorithm has been used for the multiobjective optimal design of the FLC driven HMD system, where the minimization of the non‐dimensionalized peak displacement, acceleration and rotation of the structure about its vertical axis, have been as the three objective functions. The proposed multiobjective optimal fuzzy logic controller has been verified for an example problem reported in the literature. This HMD system consists of four HMDs arranged in such a way that the system can control the torsional mode of vibration effectively in addition to the flexure modes of vibration. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献