地震强度因子M_f值在华南和东北地区中强以上地震前的中短期异常变化

用反映地震活动增强特征的地震强度因子Mf 值,系统研究了其在华南和东北地区中强以上地震前的中短期( T≤1 年) 异常变化。结果发现在震前1 年左右,半数震例的震中附近地区出现Mf 值中期异常区明显收缩,即可认为出现Mf 值中短期异常,亦即认为当前已进入地震孕育的中短期阶段。笔者通过对Mf 值在华南和东北地区中强以上地震前在时间和空间上的异常变化研究后认为:该值在上述地区的地震中短期预报中具有一定预报效果     

土建结构振动控制研究进展

介绍了结构控制研究的任务、主要的减振装置、结构的主动控制和被动控制、结构的开环和闭环控制及其相应的算法;对土建结构控制研究的进展进行了综述,并列举了土建结构振动控制的工程应用实例;对土建结构控制研究的内容、研究方法和研究队伍等提出了建议。     

PREDICTING BASE FLOW USING HYDROGEOLOGIC PARAMETERS1

ABSTRACT: A method is presented for predicting base flow using easily measured, or estimated, hydrogeologic parameters. A mathematical model based upon the theory of subsurface flow to parallel drains is applied to a small watershed in Oklahoma. An example of model application is presented for a five-year period of record from this small watershed. Three years of data are used to calibrate the model, and two years of data are used for model validation. Hydrographs of observed and predicted base flow are presented for the five-year period of record. We concluded from this limited application of the model, on a small watershed, that the modeling techniques discussed herein were valid and should be tested for longer time periods on a larger watershed to determine their general applicability.     

THE RELATIONSHIP BETWEEN THE TIME BASES OF SIMULATION MODELS AND THEIR STRUCTURE1

ABSTRACT: The time base of a simulation model can be defined as a combination of two time intervals. One is the interval used for input and internal computations. The second is the interval used for the output and calibration of the model. The time base of a model is related on the one hand to the type of applications for which the simulated data are used, and on the other hand to the structure and complexity of the model. The latter may be represented by the number of parameters employed to specify the operation of the model. Using data typical to relatively small watersheds in a semiarid climate, the interaction between the complexity of a series of models and the time bases used by them was studied. This included the effects of the two factors, time base and complexity, on the values of the optimal parameters, prediction of mean annual flow, and general performance of the models. The main conclusion is that if the acceptable time base is longer, the model can be less complex needing fewer parameters. There is also an advantage in using a time base comprising a shorter input time interval and a longer output time interval.     

Organizing knowledge for tutoring fire loss prevention

The San Bernardino National Forest in southern California has recently developed a systematic approach to wildfire prevention planning. However, a comprehensive document or other mechanism for teaching this process to other prevention personnel does not exist. Anintelligent tutorial expert system is being constructed to provide a means for learning the process and to assist in the creation of specific prevention plans. An intelligent tutoring system (ITS) contains two types of knowledge—domain and tutoring. The domain knowledge for wildfire prevention is structured around several foci: (1) individual concepts used in prevention planning; (2) explicitly specified interrelationships between concepts; (3) deductive methods that contain subjective judgment normally unavailable to less-experienced users; (4) analytical models of fire behavior used for identification of hazard areas; (5) how-to guidance needed for performance of planning tasks; and (6) expository information that provides a rationale for planning steps and ideas. Combining analytical, procedure, inferential, conceptual, and expositional knowledge into a tutoring environment provides the student and/or user with a multiple perspective of the subject matter. Aconcept network provides a unifying framework for structuring and utilizing these diverse forms of prevention planning knowledge. This network structure borrows from and combines semantic networks and frame-based knowledge representations. The flexibility of this organization facilitates an effective synthesis and organization of multiple knowledge forms.     

南昌市名特优农产品生产基地布局规划

本文通过对南昌市名特优农产品资源、生产现状和市场条件的综合分析，确立了发挥地区资源优势，重点发展的名特优农产品，并进行了科学合理的规划和布局。     

海洋信息工程安全生产管理体系建设研究

海洋信息工程是战略性与风险性并存的新兴产业,如何科学构建安全生产管理体系、有效管控安全风险,成为各界关注的重点。本文分析了海洋信息工程的高风险性,围绕风险管控探索海洋信息工程安全生产管理体系建设的原则和策略,创新地提出"三全"法、一库四系统、多元共治等风险辨识治理措施,为海洋信息工程安全生产管理体系建设提供多种方法。     

Infrared spectroscopic probing of dimethylamine clusters in an Ar matrix

Amines have many atmospheric sources and their clusters play an important role in aerosol nucleation processes. Clusters of a typical amine, dimethylamine (DMA), of different sizes were measured with matrix isolation IR (infrared) and NIR (near infrared) spectroscopy. The NIR vibrations are more separated and therefore it is easier to distinguish different sizes of clusters in this region. The DMA clusters, up to DMA tetramer, have been optimized using density functional methods, and the geometries, binding energies and thermodynamic properties of DMA clusters were obtained. The computed frequencies and intensities of NH-stretching vibrations in the DMA clusters were used to interpret the experimental spectra. We have identified the fundamental transitions of the bonded NH-stretching vibration and the first overtone transitions of the bonded and free NH-stretching vibration in the DMA clusters. Based on the changes in vibrational intensities during the annealing processes, the growth of clusters was clearly observed. The results of annealing processes indicate that DMA molecules tend to form larger clusters with lower energies under matrix temperatures, which is also supported by the calculated reaction energies of cluster formation.     

苯胺蓝脱色放线菌的分离及脱除特性研究

通过苯胺蓝平板法从陕西秦岭森林高度腐殖化土壤中分离得到一株具有高度碳源利用多样性放线菌AG-56,经16S r RNA鉴定为链霉菌属(Streptomyces),命名为Streptomyces AG-56,Gen Bank登录号KU925845.同时,考察了Streptomyces AG-56在液体条件下对苯胺蓝的降解能力.结果显示,菌株AG-56对苯胺蓝的3个波长(602、314、192 nm)吸收基团都具有不同程度的降解能力,并伴有物理吸附作用,其中对602 nm处基团具有最大的脱除能力,脱除率为72%.菌株AG-56在污水脱色方面特别是对三芳基甲烷类染料废水处理方面展现出了巨大的应用潜能.     

认识电磁辐射 畅享绿色生活

电磁辐射是能量以电磁波的形式在空间传播方式,人类赖以生存的地球本身就是一个巨大的电磁场环境,由于人工电磁辐射源的应用,使得电磁场环境趋于复杂化,但只有超过国家规定的电磁环境质量标准时,才称为电磁环境污染.近来,电磁环境信访投诉事件剧增,人们需正确认识电磁辐射,才能安心工作和生活,电磁类建设项目才能更好地服务人们,才能更高效地促进社会发展.