江苏台网尾波持续时间震级的初步研究

利用江苏台网15个地震台的84个地震DD-1短周期记录资料,通过m_(Lg)震级与持续时间τ和震中距Δ相关,得出该区持续时间震级M_D公式:M_D=a_0+0.44(lgτ)~2+0.00036Δ+DM这里,a_0为与记录分向和尾波截止水平有关的常数;DM为台站校正值。M_D标度内部单台标准差为0.09～0.10震级单位,M_D相对m_(Lg)的单台标准差为0.16～0.17震级单位。     

循环冷却水高浓缩倍率处理技术在电厂的应用研究

随着淡水资源的日益紧缺,如何提高水资源的利用率以达到节约用水的目的引起更高的关注.基于河南某电厂循环冷却水浓缩倍率仅为2.0的现状,选取两种新型高效的水处理药剂(1号、2号).经试验研究确定处理效果更佳的1号药剂为选择药剂,并确定最佳投药量为8 mg/l.将1号药剂应用到实际工程中,循环水浓缩倍率提高至6.5以上,节省了大量的水资源,同时减少废水的排放量,为该电厂带来了良好的经济和环境效益,也为类似工程的建设提供一定的参考作用.     

控制森林大火系统工程

本文论述林火管理中防止大火成灾的重要性,并以系统工程为主要手段,通过计算机运算提供的数据,指挥人员选用相对优化的决策。依靠现代化的灭火技术,最大限度地制止大火蔓延直到熄灭,其目标是把火灾损失限制在最小程度.     

基于大型无脊椎动物完整性的赤水河健康评价体系构建

作为长江上游珍稀鱼类国家自然保护区的核心区,赤水河流域水系的健康状况虽颇受关注,但相关评价工作却较少。笔者结合现场调查(2016年)和历史数据(2007年),初步构建基于大型无脊椎动物群落的健康评价体系,对赤水河干流和部分支流的不同季节(春季和秋季)和不同河段(上中下游)的健康状况进行评估。指标筛选结果显示:赤水河上游河段在春季和秋季分别包括6、2个核心参数,中游河段分别包括5、4个,下游包括3、2个核心参数。通过四分法将健康状态划分为4个等级:健康、亚健康、一般和不健康。从整体上看,赤水河处于亚健康状态,且春季和秋季河流不同采样点健康状况有所差异,春季健康状况好于秋季。回归分析显示,BOD_5、COD_(Mn)以及NH~+_4-N是影响赤水河健康的主要环境因子。研究所构建的B-IBI评价指标较好地评估了赤水河的健康状况,可作为赤水河流域水体环境监测的有效手段之一。     

通用森林火险级系统

根据火烧试验,研究出来一套包括火险等级、火行为与火烈度等的完整系统.用公式R_0=aT bV ch-D计算日燃烧指标R_0(米/分)。此方法曾于1991年5月试用在小兴安岭伊春林区得出满意的结果。     

预涂动态膜强化渗透与截留性能研究

以二氧化钛粉体材料为涂膜剂,陶瓷管为基膜制备预涂动态膜,引入通量增强系数Zi和截留增强系数Fi研究了预涂动态膜制备条件对其强化渗透与截留性能的影响,并用SEM电镜对预涂动态膜和基膜表面形貌进行表征。结果表明:制备的预涂动态膜表面均匀密实,其孔径低于基膜平均孔径。预涂动态膜的渗透与截留性能随涂膜液pH值的增加而增加,在跨膜压差低于0.2 MPa、错流速度低于1.5 m/s,涂膜时间少于30 m in和涂膜液浓度低于0.4 g/L范围内,提高这些参数值有利于提高预涂动态膜的渗透与截留性能,超出此范围时,提高这些参数值对增强其渗透与截留性能的效果已不明显,其中错流速度的影响相对小些。跨膜压差为0.2 MPa,错流速度为1.5 m/s,涂膜时间30 m in,涂膜液浓度和pH值分别为0.4 g/L和10.2时为最佳制备条件。     

Environmental filtering in the dry season and spatial structuring in the wet: different fish community assembly rules revealed in a large subtropical floodplain lake

Although environmental filtering and spatial structuring are commonly regarded as two key factors shaping community dynamics, their relative contribution remains unknown for numerous aquatic ecosystems, particularly highly dynamic floodplain lakes. This issue is here addressed by examining the seasonal metacommunity dynamics of freshwater fishes in Lake Dongting, a large subtropical lake of the middle Chang-Jiang basin in southern China. Physicochemical variables and fish assemblages were recorded at 20 sampling sites during the wet, normal, and dry seasons. Distance-based redundancy analysis and associated variation partitioning were used to examine the relative role of environmental variables and spatial factors in fish community assembly in each season. Analysis results demonstrated that the relative contribution of environmental filtering and spatial structuring varied depending on environmental features and the extent of hydrological connectivity in different seasons. Intensified physicochemical parameters in the dry season convinced the enhanced environmental filtering, whereas high hydrological connectivity in the wet season favored the stronger spatial process. Specifically, the community assembly processes were temporally dynamic; spatial structuring (or mass effects), resulting from excessively high dispersal rates, was dominant during the flooding season, and environmental filtering was stronger than spatial structuring (or dispersal limitation) during the non-flooding season. These findings highlight the importance of conserving local habitats of Lake Dongting during the dry and normal seasons, and maintaining of the flood pulse of the lake and its natural variability during the wet season. Apparently, the construction of a water-level regulation project at the Chenglingji Channel, the outlet watercourse of Lake Dongting, is not supported because it will change the flood pulse of this lake and thus impact habitat heterogeneity or variability.