基于韦伯-费希纳定律的营养状态普适韦伯指数公式

在适当设定各营养状态指标参照值Cj0的基础上,用相应于参照值Cj0的指标规范值xj作为基于韦伯-费希纳定律的营养状态指数公式中的刺激量.由于各项指标的同级营养状态标准的规范值xjl差异不大,从而可认为各指标的营养状态韦伯指数公式都具有一个共同适用的韦伯常数α,并采用智能解域搜索算法优化α,得出对所有14项营养指标皆适用的营养状态普适韦伯指数公式.将营养状态韦伯指数公式应用于数十个湖泊的富营养化评价,并与其它多种方法的评价结果进行比较,结果表明该公式不但理论依据充分,而且具有简单、适用的特点.     

班公湖—怒江成矿带商旭造山型金矿床Ⅲ号矿段深部找矿潜力研究

西藏双湖县商旭造山型金矿床位于班公湖—怒江缝合带中段,矿体受NWW向的脆—韧性断裂构造控制,呈似层状、脉状产于中—下侏罗统木嘎岗日群混杂岩中。围岩为炭质板岩、变石英砂岩等。矿石类型主要为石英脉型和构造蚀变岩型,矿石构造以细脉状和角砾状为主,矿石矿物为自然金。矿床学与同位素地球化学研究认为木嘎岗日群含金建造为商旭金矿提供了主要物质来源,NWW向脆—韧性断裂构造为含金热液的运移和金的沉淀供了运输通道和就位空间,羌塘南缘早白垩世构造—岩浆活动为含金热液的运移提供了热动力,矿区内NWW向构造破碎带中变形强烈,具黄铁矿化、硅化蚀变的地段,为本矿区的找矿有利地区。土壤地球化学调查显示,Ⅲ号矿段南部,T-4、T-5异常区域具有较好的找矿潜力;电法测深资料显示,Ⅲ号矿段的控矿构造在深部还有延伸,并可能与区域较深大的断裂相连。综合分析认为,Ⅲ_(1-2)号矿体在标高4200m以下还具有较大的找矿潜力,通过进一步地质勘查工作,有望提高金资源量,扩大矿床规模。同时,初步总结了商旭造山型金矿床"找矿三步组合拳"的勘查工作方法。     

Extended survival of several organisms and amino acids under simulated martian surface conditions

Recent orbital and landed missions have provided substantial evidence for ancient liquid water on the martian surface as well as evidence of more recent sedimentary deposits formed by water and/or ice. These observations raise serious questions regarding an independent origin and evolution of life on Mars. Future missions seek to identify signs of extinct martian biota in the form of biomarkers or morphological characteristics, but the inherent danger of spacecraft-borne terrestrial life makes the possibility of forward contamination a serious threat not only to the life detection experiments, but also to any extant martian ecosystem. A variety of cold and desiccation-tolerant organisms were exposed to 40 days of simulated martian surface conditions while embedded within several centimeters of regolith simulant in order to ascertain the plausibility of such organisms’ survival as a function of environmental parameters and burial depth. Relevant amino acid biomarkers associated with terrestrial life were also analyzed in order to understand the feasibility of detecting chemical evidence for previous biological activity. Results indicate that stresses due to desiccation and oxidation were the primary deterrent to organism survival, and that the effects of UV-associated damage, diurnal temperature variations, and reactive atmospheric species were minimal. Organisms with resistance to desiccation and radiation environments showed increased levels of survival after the experiment compared to organisms characterized as psychrotolerant. Amino acid analysis indicated the presence of an oxidation mechanism that migrated downward through the samples during the course of the experiment and likely represents the formation of various oxidizing species at mineral surfaces as water vapor diffused through the regolith. Current sterilization protocols may specifically select for organisms best adapted to survival at the martian surface, namely species that show tolerance to radical-induced oxidative damage and low water activity environments. Additionally, any hypothetical martian ecosystems may have evolved similar physiological traits that allow sporadic metabolism during periods of increased water activity.     

一个FUZZY聚类分析的快速算法

Fuzzy聚类分析,是近年来在气象预报等很多科学领域中广泛应用的一种客观分析技术。本文根图的可迁闭包性质,探讨从模糊相似矩阵R中节点的可达性问题着手,生成相应的深度优先生成树(DFT)来完成聚类,从而得到一个时间复杂性为O(n~2)的快速Fuzzy聚类算法。     

基于磁通负反馈结构的高灵敏度感应式磁场传感器研制

感应式磁场传感器广泛应用于地球物理电磁勘探仪器,但也是阻碍我国地球物理电磁勘探仪器装备研发和推广应用的瓶颈技术.在我国SinoProbe计划中"地面电磁探测(SEP)系统"项目支持下,我们研制出用于大地电磁测深(the Magnetotellurics MT)方法的高灵敏度磁场传感器.研制过程中,采用磁通负反馈技术,增强传感器系统工作稳定性;采用斩波稳零放大电路技术,有效降低低频1/f噪声对传感器灵敏度的影响;采用高磁导率合金材料,增加磁场传感器的灵敏度.最终,MT磁场传感器工作频率范围为1 m√HZ~1 k√HZ,噪声水平0.1 √HZ时为1.5 pT/√HZ;1 √HZ时为0.15 pT/√HZ;10 √HZ时为0.03 pT/√HZ;长度96 cm,重量≤6 kg.理论和测试结果表明:与同类产品比较,本文研制的感应式磁场传感器在≥10 √HZ时,平均噪声水平从150 fT/√HZ,下降至30 fT/√HZ,噪声水平更优,测量精度更高,能够更好地满足MT方法的需求.     

Application of Harmony Search algorithm to the solution of groundwater management models

This study proposes a groundwater resources management model in which the solution is performed through a combined simulation-optimization model. A modular three-dimensional finite difference groundwater flow model, MODFLOW is used as the simulation model. This model is then combined with a Harmony Search (HS) optimization algorithm which is based on the musical process of searching for a perfect state of harmony. The performance of the proposed HS based management model is tested on three separate groundwater management problems: (i) maximization of total pumping from an aquifer (steady-state); (ii) minimization of the total pumping cost to satisfy the given demand (steady-state); and (iii) minimization of the pumping cost to satisfy the given demand for multiple management periods (transient). The sensitivity of HS algorithm is evaluated by performing a sensitivity analysis which aims to determine the impact of related solution parameters on convergence behavior. The results show that HS yields nearly same or better solutions than the previous solution methods and may be used to solve management problems in groundwater modeling.     

Water volume differentially modifies copepod predatory strengths on two prey types

Predatory interaction strengths are highly context-dependent, and in temporary aquatic ecosystems, may be affected by water volume changes. We examine the influence of water volume on Lovenula raynerae (Copepoda) functional responses towards two temporary pond prey types. Daphnia prey risk was not affected by increasing water volume, whereas for Culex prey risk was reduced. Accordingly, water volume changes through the hydroperiod may have species-specific effects on prey, with implications for population persistence under environmental change.     

基于二叉树的启发式搜索算法改进

最短路径是现代物流配送研究中热点问题之一,在分析传统启发式搜索算法的基础上,针对算法在路径优化中存在的不足,提出基于二叉树优化启发式搜索算法（A＊）实现所需结点之间最短路径查询,在引入已知的全局信息条件下选择下一个被检查的结点,并根据用户给出的起始顶点与目标顶点以及搜索的角度查找最短路径,从而搜索可能性较大的结点,提高搜索过程的效率.实验表明,基于二叉树的A＊比A＊效率提高11％～26％.     

Ultra-low-frequency (ULF) and total electron content (TEC) anomalies observed at Agra and their association with regional earthquakes

Employing a three-component search coil magnetometer (f = 0.01–30 Hz) the ultra-low-frequency (ULF) magnetic field observations have been taken in a noise free rural site at Bichpuri, Agra, India since 20 April 2007. We have analysed 7 months of night time data from 01 May to 30 November 2007. The data show seven occurrences of ULF bursts with periods ranging from a few minutes to an hour in a wide frequency range up to 15 Hz. The occurrence of such ULF bursts has been statistically analysed. The polarization parameter analysis shows that two of these bursts occurred from sources in the ionosphere and magnetosphere (Z/X < 1). It is further seen that four bursts correlated very well with some regional earthquakes (M > 4.5), which occurred at distances less than 628 km from the observation site at Agra. In some cases the bursts occurred 1–3 days prior to the main shocks.Since earthquakes are also known to perturb the ionosphere, we have analysed total electron content (TEC) data obtained from a GPS receiver stationed at Agra since June 2006. Analysis of the data for the same period as the magnetic field observations shows that there existed TEC anomalies on all the days when ULF bursts occurred. The TEC anomalies show enhancement and depletion in the data in all cases. While the mechanisms of the ULF and TEC anomalies are not well known, it is expected that the ULF bursts occurred due to microfracturing of the earth's crust during stress accumulation and that the TEC anomalies occurred as a result of the electric field induced in the ionosphere during such processes.     

兰州国家陆地搜寻与救护基地建设功能及成效浅析

介绍了兰州国家陆地搜寻与救护基地的功能定位,训练设施、救援装备及救援队伍的建设成果及建设作用。通过岷县漳县地震的救援行动以及开展的几次救援队伍培训工作,展现了兰州国家陆地搜寻与救护基地在建成后已在逐渐发挥其应有的作用和功效。