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1.
选择由美国农业部农业研究中心研制开发的SWAT模型,以该模型与GIS结合的方式,建立了西溪流域水循环地理信息系统平台.应用该模型,对不同气温和降雨组合下的情景进行模拟,表明降雨量变化是影响西溪径流量变化的主要因素. 相似文献
2.
The rapid urbanization and industrialization involve an unsustainable use of natural systems,leading to various problems in cities.The urban hydrological system experiences fluctuating amount of surfac... 相似文献
3.
张亚智 《杨凌职业技术学院学报》2012,(4):1-3,9
在研究和分析灌区灌溉调度、农业生产条件时,常遇到天气“灾变”的问题。若遇到年径流量多、年内分配不均衡的丰水年份,对灌区水库来说,不但需要“放水”灌溉,还要考虑“拦洪”、“弃水”和“蓄水”等问题的合理安排,以减少丰水年可能引起的“涝灾”;若遇到年径流量小的枯水年份,利用水库在丰水期存人的水量,放水灌溉以缓解“旱情”的增加。为了充分利用水库调节径流在时空间重新分布的功能,减少、缓和因天气“灾变”而出现的“旱、涝”问题,了解和掌握来年的年径流量水文气象指标的变化,以决定当年水库运行策略是十分必要的。因而对来年或中长期年径流量水文指标进行灰色概率预测是很有实际意义的。 相似文献
4.
采用Morlet小波函数对龙川江流域1960—2008年径流量时间序列进行了多尺度周期性分析,通过小波方差确定径流序列的主要周期,并根据径流主周期对未来径流量变化进行了预测。结果表明：径流量变化的时间尺度为6a、20a和12a,其中12a的周期振荡最强,为径流量变化主周期;依据主周期的变化趋势,预测2009年前后龙川江流域年径流量将偏多,大约在2010—2020年径流量将偏少。因此,小波分析可以用来进行水资源量的趋势分析,为区域水资源的合理开发利用和未来决策提供依据。 相似文献
5.
基于岷江流域近52年(1961-2012)的径流与气象数据,采用线性回归、非参数检验(Mann-Kendall法)、Morlet小波变换、Pearson相关分析等方法,对岷江流域径流、气温、降水等主要水文气象要素进行分析.结果显示:(1)近52年来岷江流域年平均气温总体呈明显增长趋势,年均降水量呈显著下降趋势,年均气温以0.15℃/10 a的速率增加,年均降水量以20.18 mm/10 a的速率减少,区域气候的暖干化趋势明显.(2)岷江流域多年径流量呈显著减少趋势,减少速率为20.38×108m3/10 a,流域径流量在1968年左右出现减少突变,20世纪70年代早期开始径流量增加,1993年左右又发生一次减少突变,径流显著减少.(3)通过对年径流量序列进行Morlet小波转换分析发现,岷江流域径流量主要存在69 a的年际周期、17 a和28 a的年代际周期,径流量总体特征是向干枯化趋势发展.(4)通过年径流量与气象因素的相关分析发现,区域降水量是影响岷江流域径流减少的主导因子,在该流域降水量减小的背景下,气温升高进一步加剧了流域径流量的减小;流域径流对暖干气候的响应表现为径流量减少. 相似文献
6.
Haimanot Habte Lemji Hartmut Eckstädt 《Journal of Zhejiang University. Science. B》2013,14(10):924-933
Evaluating the performance of a biotrickling filter for the treatment of wastewaters produced by a company manufacturing beer was the aim of this study. A pilot scale trickling filter filled with gravel was used as the experimental biofilter. Pilot scale plant experiments were made to evaluate the performance of the trickling filter aerobic and anaerobic biofilm systems for removal of chemical oxygen demand (COD) and nutrients from synthetic brewery wastewater. Performance evaluation data of the trickling filter were generated under different experimental conditions. The trickling filter had an average efficiency of (86.81±6.95)% as the hydraulic loading rate increased from 4.0 to 6.4 m3/(m2·d). Various COD concentrations were used to adjust organic loading rates from 1.5 to 4.5 kg COD/(m3·d). An average COD removal efficiency of (85.10±6.40)% was achieved in all wastewater concentrations at a hydraulic loading of 6.4 m3/(m2·d). The results lead to a design organic load of 1.5 kg COD/(m3·d) to reach an effluent COD in the range of 50–120 mg/L. As can be concluded from the results of this study, organic substances in brewery wastewater can be handled in a cost-effective and environmentally friendly manner using the gravel-filled trickling filter. 相似文献
7.
建筑垃圾对城市雨水径流中Pb的吸附特性(英文) 总被引：2，自引：0，他引：2
以砖混建筑垃圾为研究对象,采用人工模拟雨水,通过静态和动态吸附实验研究了不同粒径粒级建筑垃圾对雨水径流中Pb的吸附效果.实验结果表明:准二级动力学模型比准一级动力学模型能更好地描述建筑垃圾对Pb的吸附过程;Freundlich等温模型能较好地拟合其等温吸附过程;不同粒径粒级建筑垃圾均对雨水径流中的Pb具有较好的净化效果,去除率高达99%,粒径粒级越小,对Pb的净化效果越好,但其渗透性能越差;建筑垃圾的粒径粒级对Pb的吸附平衡时间、吸附速率和吸附量具有重要影响,粒径2.36~4.75mm的建筑垃圾对Pb的平衡吸附速率和平衡吸附量最大,分别为18.1μg/min和5.5μg/g.上述研究结果为城市雨水径流中Pb污染的有效控制以及建筑垃圾资源化提供了科学依据. 相似文献
8.
渭河林家村站径流变化趋势分析 总被引：1，自引：0，他引：1
运用灰色系统理论分析渭河林家村站1956-2000年以来径流量的变化趋势,以绝对关联度定量描述径流量与主要影响因素之间的关系,说明引起渭河林家村站径流量变化趋势的原因之一是流域年降水量的变化,而且与年平均气温有一定的关系,为河川径流变化趋势成因分析提供了一种新的思路。 相似文献
9.
毕节试验区是典型的岩溶山区,岩溶面积约占全区总面积的70％,其境内的六冲河流域面积占全区总面积38.1％;年径流量占全区总径流量39.5％.应用改进的SWAT分布式水文模型建立其降雨一径流模型,得到流域的水循环模式,进而推广到毕节市全域.根据数值模拟结果和调查资料计算表明,毕节市地表水资源供需矛盾突出;地下水资源虽然丰富,但利用率极低,工程性缺水明显.因此,必需对毕节市地下水资源作专项研究,合理开发,才能适应当地经济社会发展的客观要求. 相似文献
10.
《Learning and individual differences》2007,17(3):280-290
Attributional retraining (AR) is a motivational intervention that consistently produces improved performance by encouraging controllable failure attributions. Research suggests that cognitively engaging AR methods are ideal for high-elaborating students, whereas affect-oriented techniques are better for low-elaborating students. College students' (N = 749) elaborative learning was assessed in the first semester, after which students were assigned to one of three writing-based AR conditions (No AR, Cognitive AR, Affective AR). Academic performance (course grades, GPA), motivation, attributions, and emotions were assessed in the second semester. AR by elaboration (low/high) 3 × 2 ANCOVAs showed optimal results for high elaborators following cognitive AR, and for low elaborators following affective AR. Performance improvements for the former were mediated by improved cognitions (expectations), and for the latter were mediated by increased positive affect. 相似文献
11.
Children's perseverative appearance-reality errors are related to emerging language skills 总被引：1，自引：0，他引：1
Two experiments explored the communicative bases of preschoolers' object appearance-reality (AR) errors. In Experiment 1, 3-, 4-, and 5-year-olds (N = 36) completed the AR test (with high- and low-deceptive objects), a control test with the same discourse structure but nondeceptive stimuli, and stimulus naming and memory tests. AR performance correlated positively with control (discourse) and naming test performance. Object deceptiveness had little effect. In Experiment 2, 3- and 4-year-olds (N = 64) completed AR tests that experimentally varied question phrasing and use of exemplar objects. Children also completed memory, vocabulary, and control tests (of verbal perseveration). AR performance variance was predicted by a composite perseveration score from three non-AR tasks, vocabulary, and exemplars. The results indicate that the discourse structure of the AR test elicits a perseverative tendency that is mediated by children's verbal knowledge. 相似文献
12.
选用1964～1990年内金沙江上游和下游14个雨量站资料进行降水特征分析,结果表明:降水地区分布相当不均匀,年内主要集中分配在汛期6～9月,年际变化不大;选用金沙江干支流上4个控制站年径流系列进行特征分析,结果表明:径流深地区分布不均匀,年内分配不均匀,丰枯周期明显,年际变化不大。 相似文献
13.
Isabella Meneghel Isabel M. Martínez Marisa Salanova Hans de Witte 《Psychology in the schools》2019,56(6):875-890
The aim of this article is twofold: (a) to validate the psychometric properties of the Academic Resilience Scale (AR‐S) in a Spanish university context; and (b) to test a model where different coping strategies are antecedents of AR, and where academic satisfaction and performance are its consequences. The studies were conducted with 185 (study 1) and 780 (study 2) students. In study 1, the construct validity, reliability, and convergent and divergent validity of the AR‐S were analyzed. The hypothesized model (study 2) was tested using structural equation modeling. The results confirmed the good psychometric properties of the AR‐S in the Spanish context, providing evidence of its validity. Furthermore, the distinctive role of different coping strategies in resilience was confirmed, as well as the relationship between resilience and academic satisfaction. No direct relationship between resilience and performance was found, highlighting the full mediation of satisfaction. 相似文献
14.
《Structural equation modeling》2013,20(2):174-205
This research was designed to investigate how much more suitable moving average (MA) and autoregressive-moving average (ARMA) models are for longitudinal panel data in which measurement errors correlate than AR, quasi-simplex, and 1-factor models. The conclusions include (a) when testing for a stochastic process hypothesized to occur in a longitudinal data set, testing for other processes is necessary, because incorrect models often fit other processes well enough to be deceiving; (b) when measurement error correlations are flagged to be relatively high in panel data, the fit and propriety of an MA or ARMA model should be considered and compared to the fit and propriety of other models; (c) when an MA model is fit to AR data, measurement error correlations may nonetheless be deceptively high, though fortunately MA model fit indexes are almost always lower than those for an AR model; and (d) the assumption that longitudinal panel data always contain measurement error correlations is patently false. In summary, whenever evaluating longitudinal panel data, the fit, propriety, and parsimony of all 5 models should be considered jointly and compared before a particular model is endorsed as most suitable. 相似文献
15.
A laboratory-scale trickling biofilter column,filled with Raschig rings and inoculated with Pseudomonas putida (ATCC 1785)was used to purify chlorobenzene contained waste gases.Sodium dodecyl sulfonate(SDS)was used to enhance the performance of trickling biofllter.Purification performance of the trickling biofilter was examined for chlorobenzene inlet concentration of 1.20～5.04 g/m~3 at different EBRTs between 76～153 s.Without SDS addition,with simultaneous increase in chlorobenzene inlet loading rate and gas flow rate,100% removal efficiency was achieved at EBRT of 109 s and inlet loadings below 5120 mg/m~3.Addition of SDS to nutrient solution led to improvement of trickling biofilter purification performance. By introducing 25 mg/L SDS,the removal efficiency was increased by 21% and elimination capacity up to 234 g/(m~3.h)was achieved at chlorobenzene inlet loading of 241 g/(m~3.h).Although SDS concentration experienced a low rate reduction after continuous nutrient solution recirculation,this result has little influence on trickling biofilter's removal efficiency in monitoring period. 相似文献
16.
Application of developed Grid-GA distributed hydrologic model in semi-humid and semi-arid basin 总被引：1，自引：0，他引：1
A grid and Green-Ampt based(Grid-GA)distributed hydrologic physical model was developed for flood simulation and forecasting in semi-humid and semi-arid basin. Based on topographical information of each grid cell extracted from the digital elevation model (DEM) and Green-Ampt infiltration method, the Grid-GA model takes into consideration the redistribution of water content, and consists of vegetation and root interception, evapotranspiration, runoff generation via the excess infiltration mechanism, runoff concentration, and flow routing. The downslope redistribution of soil moisture is explicitly calculated on a grid basis, and water exchange among grids within runoff routing along the river drainage networks is taken into consideration. The proposed model and Xin’anjiang model were applied to the upper Lushi basin in the Luohe River, a tributary of the Yellow River, with an area of 4 716 km2 for flood simulation. Results show that both models perform well in flood simulation and can be used for flood forecasting in semi-humid and semi-arid region. 相似文献
17.
The feasibility and performance of nitrogen removal from municipal sewage were investigated through the completely autotrophic nitrogen removal over nitrite (CANON) process in a continuous reactor. CANON process was successfully started up with the transformation of nitrogen into gas by mass-balance analysis. For the synthetic waste-water (up to 480 mg NH4+-N/(L·d)), removal rates of the ammonia nitrogen and total nitrogen (TN) were about 80% and 55%, respectively, at 1.25 h hydraulic retention time (HRT). For the secondary effluent of municipal sewage, the effluent concentrations of NH4+-N and TN were below 5 mg/L and 9 mg/L, respectively. It is in accordance with the water quality standard for scenic environment with the reuse of urban recycling water (GB/T 18921-2002). 相似文献
18.
Danielle N. Pappas Christopher H. Skinner Amy L. Skinner 《Psychology in the schools》2010,47(9):887-902
An across‐groups (classrooms), multiple‐baseline design was used to investigate the effects of an interdependent group‐oriented contingency on the Accelerated Reader (AR) performance of fourth‐grade students. A total of 32 students in three classes participated. Before the study began, an independent group‐oriented reward program was being applied (i.e., a student received access to a tangible reward after passing each AR comprehension test). This program was supplemented with an interdependent group‐oriented contingency, and results showed that the number of quizzes passed per week increased immediately after the intervention was applied; however, this increase was not maintained. When students were divided into ability groups based on their average baseline performance, the lowest performing students exhibited a statistically significant increase in quiz performance (i.e., quizzes taken, quizzes passed, and book level), but no significant changes were found in the average and high performing groups. © 2010 Wiley Periodicals, Inc. 相似文献
19.
大湖口水文站枯水流量小,枯季径流占全年径流的比重一般小于5％。为了解决枯季测验和整编难的问题,在对多年资料进行分析论证的基础上,提出了在控制年径流总量的前提下,对枯季流量进行监测与停测,采用多年单值化综合线进行整编的构想,对水文巡测进行了有益探索。 相似文献
20.
为评估降雨路面径流汞(Hg)污染状况,对南京绕城高速公路马群段11场降雨路面径流进行了监测,分析了汞(Hg)的事件平均浓度(EMC)以及降雨特性对径流中Hg污染的影响.结果表明,不同赋存状态的Hg的污染程度均较为严重,总Hg(THg)、溶解态汞(HgD)和颗粒态汞(HgP)含量分别为0.173~3.347,0.069~0.862和0.104~2.485μg/L.THg的EMC超过了中国《地表水环境质量标准(GB 3838—2002)》中5类水的限值.雨水径流中Hg主要以颗粒态存在,络合态Hg(Hgre,0.250~2.821μg/L)的含量远大于挥发性Hg(Hg0,0.023~0.215μg/L)和活性Hg(Hg2+,0.026~0.359μg/L).各种降雨特性对径流中Hg污染的影响顺序为前期晴天数径流时间降雨历时降雨强度降雨量. 相似文献