受限空间烟气运动的盐水模拟原理

考虑烟气的浮力作用，合理地选取流场的特征参数，将烟气运动和盐水运动的基本方程无量纲化，分析两者之间的相似性，得到４个定性相似准则，其中Ｒｅ数是最主要的相似准则．并举例说明缩尺的盐水模拟实验可以满足相似准则。     

地质动力区划预测煤与瓦斯突出

为了确定煤与瓦斯突出矿井的突出危险区域,威胁区域和安全区域,提出基于地质动力区划的多因素模式识别概率预测方法预测煤与瓦斯突出的新思路。以鸡西滴道矿立井为研究对象,利用地质动力区划方法确定不同尺度和级别构造运动的特征,建立板块构造学说与矿井工程实际的联系,将对矿井煤与瓦斯突出产生影响的因素为参数,采用多因素模式识别概率预测方法划分研究区域内的危险区域。研究表明该方法对煤与瓦斯突出区域预测的合理性与有效性,可以在实际工程中应用推广。     

基于光谱分析的生物结皮提取研究——以毛乌素沙地为例

利用典型地物高光谱数据和TM遥感影像,对毛乌素沙地处于旺盛生长期(7-9 月)的由苔藓结皮主导的生物结皮进行了提取研究.结果表明:① 苔藓结皮在生长期具有与绿色植物相似的光谱曲线变化趋势;红边参数显示,二者除红边位置非常接近外,红边振幅、红边宽度和红边面积差异均较大;在近红外区域,苔藓结皮比绿色植物的反射率低很多;苔藓结皮无明显的553 nm反射峰;低盖度苔藓结皮(33%)、藻类结皮和植被枯落物在整个波段光谱曲线比较接近,与裸沙相比,三者反射率均较低.② 基于TM影像,用生物结皮指数(BSCI)、归一化植被指数(NDVI)、监督分类和坡度分级相结合的方法提取生物结皮,发现苔藓结皮的像元面积为0.72×10⁴ km²,占研究区总面积的6.43%.     

环境风对高层建筑楼梯井内火灾烟气运动特性的影响

环境风会影响高层建筑楼梯井内火灾烟气的运动特性.以广州市某地真实高层建筑楼梯井为原型,采用理论分析和数值模拟相结合的方法,利用火灾动力学仿真软件FDS建立该16层高层建筑楼梯井全尺寸FDS数值模型,对环境风作用下高层建筑楼梯井内火灾烟气运动规律展开数值模拟研究,分析不同窗户开合状态、不同风向和不同风速条件下环境风对高层...     

黄土丘陵区不同土地利用类型下生物土壤结皮的入渗效应

为揭示黄土丘陵区BSCs(生物土壤结皮)的入渗特征,以甘肃省定西市安家沟小流域为例,选择荒草地、沙棘灌丛和油松林3种典型土地利用类型进行采样,采用环刀模拟法研究不同土地利用类型下苔藓结皮和地衣结皮对水分入渗的影响. 结果表明:①不同土地利用类型下的2种BSCs均明显减少初渗速率和达到稳渗所需时间,初渗速率降幅最小值、最大值分别出现在油松林、荒草地下地衣结皮;荒草地、沙棘灌丛苔藓结皮稳渗速率相对裸土分别增加2.4%、10.0%,而二者地衣结皮明显降低稳渗速率,降幅分别为45.2%和55.0%,油松林下苔藓结皮和地衣结皮稳渗速率均增幅为18.2%. ②苔藓结皮在3种土地利用类型下均促进土壤水分入渗,其入渗量调控率在荒草地、沙棘灌丛和油松林下分别是1.0%、10.0%和0.7%;而地衣结皮在荒草地和沙棘灌丛下明显阻碍水分入渗,其入渗量调控率的绝对值分别为43.9%和50.0%,在油松林下的入渗量调控率则为16.5%. ③Horton模型对生物土壤结皮入渗过程拟合效果最好,较适于描述本区具有生物结皮覆盖的土壤入渗特征.      

Adsorption and movement of carbaryl in soils: A verification of cosolvent theory and comparison of batch equilibrium and soil thin layer chromatography results

Batch equilibrium and soil thin layer chromatography (TLC) techniques were used to investigate the influence of different volume fractions of organic cosolvents (acetone and methanol) on the adsorption and movement of carbaryl in four different types of Indian soils. L-shaped isotherms were obtained for both the cosolvent–water mixtures at all f _s values and were in close agreement with the Freundlich equation. Higher adsorption was observed on F.R.I. soil (FSL) followed by Alampur soil (ASL), Kalai soil (KL), and Bhoran soil (BSL) at all f _s values for both the cosolvent systems as was anticipated from the K and K _D values. The K and K _D values also confirmed that carbaryl adsorption was higher in methanol–water mixture than acetone–water mixture and decreased with increasing f _s values. The frontal R _f values obtained from soil TLC studies were inversely proportional to the K and K _D values for both the cosolvent systems. The higher K and K _D values and lower R _f values in methanol–water mixtures relative to acetone–water mixtures for all the soils indicated that acetone had a greater potential for ground water contamination compared to methanol. The adsorption data were used to evaluate the cosolvent theory for describing adsorption of carbaryl in acetone–water and methanol–water mixtures. The aqueous phase partition coefficients, K _DW (mol g^?1), normalized with respect to f _oc for carbaryl was evaluated by extrapolating f _s → 0.     

潜叶虫潜道图像分析

为通过潜叶虫潜食叶片所留下的潜道分析其分类、行为和生态,应用Getdata图形数字化软件和R语言,提取线形潜道的数字化图像,并获得各种图像形状参数,如平均转角、转角集中度、分维D、直线度ST、蜿蜒度SN等.结果发现:大多数潜道的平均转角较小(不超过±25.0°),转角集中度较高(>0.600),说明潜食方向大多保持为前进方向;多数潜道的ST在0.010到0.300之间,数值极小,而SN一般都超过0.600,表明多数潜叶昆虫潜道的蜿蜒程度非常大;米楮上两种潜叶蛾的潜道形状参数如D和ST存在显著差异.     

三峡库区淹没区土壤重金属形态分布及其对水质影响

结合三峡水库调度模式,在汛期及汛后对库区淹没区土壤中重金属Cu,Pb,Cd,Cr的存在形态、迁移转化特征及其对水体水质的影响进行研究.结果表明:不同重金属在库区土壤中存在形态不同,Cu和Cr主要以残渣态存在,w(残渣态Cu)和w(残渣态Cr)平均值为87.41%和96.04%,而w(可提取态Pb)和w(可提取态Cd)较高,平均值为41.95%和88.14%,生态风险相对高于Cu和Cr.在汛期三峡水库低水位运行,水体重金属含量较高,汛期水体ρ(Pb)和ρ(Cd)分布特征与土壤w(Pb)和w(Cd)分布呈显著相关性,而汛后水库首次172 m高水位蓄水,由于水环境因素的改变,水体中重金属含量显著降低,汛后淹没土壤重金属形态含量变化细微,土壤淹没对库区水体水质影响小,不构成汛期、汛后水体重金属含量波动的主因.      

Modeling high-frequency position data of large herbivores with a phase-state model

Understanding the rules and factors that drive the foraging behavior of large herbivores is important to describe their interaction with the landscape at various spatial scales. Some unresolved questions refer to landscape-behavioral interactions that result in oriented or random search in seasonally changing landscapes. Remotely sensed position data indicate that herbivores select local patches of heterogeneous landscapes depending on a complex host of dynamically varying animal and environmental conditions. Since foraging paths consist in successions of relatively short steps, increasing the frequency at which position information is acquired would contribute to entangle the mechanisms resulting in herbivores’ foraging paths. We addressed the question whether herbivores would obtain information at a patch scale that would modify their distribution at a landscape scale based on directed movement or navigation ability. We considered a set of 100,000 high-frequency (1 min intervals) position data of several free-ranging sheep (Ovis aries) at a seasonal-varying range (Patagonian Monte, Argentina) and observed their movements at landscape and at single vegetation patch scales. At a landscape scale, we inspected the spatial co-variation of seasonally varying forage offer and ewes’ movement speeds. At a patch scale, we developed a phase-state (P-S) model of movement cycles based on the occurrence of behavioral phases along foraging paths, and fitted it to the observed daily time series of ewes’ movement speeds. Ewes were preferentially distributed in areas with high forage offer during periods of low forage availability and the reverse occurred during the season of high forage availability. Parameters of the model of activity cycles amenable to control by ewes (duration of speed phases, time elapsed between speed cycles) did not covariate with forage offer, but varied significantly among ewes. The shape (kurtosis) parameter of the model of movement cycles, one which is unlikely under ewes’ control, co-varied significantly with spatial forage offer but did not differ among ewes. We conclude that ewes allocated foraging time along a series of similar movement efforts irrespective of forage availability at small patches. Average forage scarcity at multi-patch level increases the ratio of searching to feeding time. This results in apparent selective time allocation to richer forage areas but does not imply evidence for oriented movement at a landscape scale. We advance a behavioral-based definition of forage patches and discuss its implications in developing foraging theory and models. The P-S model applied to high-frequency position data of large herbivores substantially improves the interpretation of the factors controlling their time allocation in space with respect to previous models of herbivore spatial behavior by discriminating among behavioral-based and environmentally induced components of their movements.     

Differences in Eye and Hand Movements of Novice and Experienced Press Operators

Presses are very widely used in industrial and commercial companies and are often the source of serious accidents occurring during operation. Most of the accidents are due to inadequate training of novice operators. Continuous recordings of eye and hand movements of five novice operators and five experienced operators in press operation were made. Significant difference between novice and experienced operators was observed in eye fixation time, eye movement patterns, hand dwell time, and eye-hand coordination. Also, differences were observed in spatial distribution of eye fixations during the die-closing portion of a stroke. There were no significant differences between novice and experienced operators in the eye and the hand movement time. The results could be used as basic data to establish a guide determining the method and training period to train novice operators.