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A Systematic Review and Meta-Analysis of Water Quality Indices 预览
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作者 Kanga Idé Soumaila Albachir Seydou Niandou +4 位作者 Mustapha Naimi Chikhaoui Mohamed Keith Schimmel Stephanie Luster-Teasley Naeem Nizar Sheick 《农业科学与技术:B》 2019年第1期1-14,共14页
Water quality indices (WQI) are useful tools for indicating the suitability of water for an expected use. However, they can suffer from some problems. The objective of this paper was to analyze the development of WQI ... Water quality indices (WQI) are useful tools for indicating the suitability of water for an expected use. However, they can suffer from some problems. The objective of this paper was to analyze the development of WQI to determine which parameters are used in water quality assessment and to discuss the characteristics of WQI. To screen articles on WQI, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method is applied to include or exclude articles. Four necessary steps are needed to design WQI: parameter selection, standardization, weighting and aggregation. A set of six methods of aggregations of sub-indices are identified: the arithmetic mean, the geometric mean, the root square, the logarithmic function, the fuzzy inference and the minimum operator. The problems encountered for the overall index are different according to the form of aggregation. They are eclipsing, ambiguity, rigidity or flexibility, adaptability and compensation. The chemical parameters (70%) are the most used in the development of WQI with the physical parameters used at 24% and the biological parameters at 6%. Dissolved oxygen (DO, 87%), total coliforms (87%), biological oxygen demand (BOD, 73%), pH (73%), temperature (67%), turbidity (60%), ammonia (53%), ammonium (47%) and total dissolved solids (47%) are the most commonly used parameters for water quality assessment. 展开更多
关键词 WATER QUALITY indices WATER QUALITY PARAMETERS WATER QUALITY assessment REVIEW META-ANALYSIS
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Impact of environmental variables on spatial and seasonal internal phosphorus loading in a mesoeutrophic lake 预览
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作者 Katarzyna Kowalczewska-Madura Ryszard Goldyn +1 位作者 Julia Bogucka Katarzyna Strzelczyk 《国际泥沙研究:英文版》 SCIE 2019年第1期14-26,共13页
Strzeszynskie Lake was formerly a slightly eutrophic(meso-eutrophic)water body.The aim of the current research was to define variables on both spatial and seasonal internal phosphorus loading from bottom sediments at ... Strzeszynskie Lake was formerly a slightly eutrophic(meso-eutrophic)water body.The aim of the current research was to define variables on both spatial and seasonal internal phosphorus loading from bottom sediments at five stations located in zones varying in depth,oxygenation,macrophyte presence,and uses of the neighboring catchment area.Ex situ experiments done with the use of intact bottom sediment cores have shown that the highest phosphorus release occurred in the deepest part of the lake and reached 3.6 mg P/m2d under anoxic conditions during summer thermal stratification.In turn,the internal loading from littoral sediments,which were well aerated all year round,was clearly lower.Furthermore,phosphorus accumulation in the bottom sediment was observed to reach a maximum of 1.45 mg P/m2 d in autumn.A comparison of the internal loading intensity in lake zones with different land uses of the neighboring catchment area has shown slightly higher values at stations adjacent to the forest catchment area than those used for recreation.Changes in the land use of the catchment area of Strzeszynskie Lake,especially the increase in impermeable surfaces,have led to an increased inflow of external loads after heavy rains,resulting in deterioration in water quality and a delayed increase in internal loading. 展开更多
关键词 BOTTOM sediments INTERSTITIAL WATER BOTTOM WATER Internal LOADING Sediment-water interface
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Modelling and development of recycled water conditioning of copper-molybdenum ores processing 预览
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作者 Irina Pestriak Valery Morozov Erdenetuya Otchir 《矿业科学技术学报:英文版》 CSCD 2019年第2期313-317,共5页
Current use of enrichment and processing technologies of ores requires the introduction of closed circuits of water treatment.A decrease in technological properties is caused by accumulations of ion-molecular componen... Current use of enrichment and processing technologies of ores requires the introduction of closed circuits of water treatment.A decrease in technological properties is caused by accumulations of ion-molecular components in the circulating water.The objective of the simulation is to determine the maximum allowable concentrations of ions and molecules as well as the choice of conditions for deposition or adsorption.First of all,our examinations decrease the concentration of copper ions and fatty acids in the circulating water.By pre-mixing water with the highest concentration of these ions,a reduction of copper ion and fatty acid concentrations in the recycled water occurs.The results do not only ensure the achievement of the maximum permitted concentration(MPC)of copper and iron,significantly reducing the amount of oxidized copper,they also make it possible to use the united sewage as current water for the flotation process.Mixing and adding filtrate of tailings,discharges of urban wastewater treatment and effluent of ash pit of thermal power stations(TPS)to recycled water causes an increase in the capacity of the enrichment plant by 15-17%. 展开更多
关键词 TAILINGS RECYCLING WATER Closed cycle Urban waste WATER CONDITIONING FLOTATION of ORE Natural WATER
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Impact of polymer mixtures on the stabilization and erosion control of silty sand slope
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作者 YANG Qing-wen PEI Xiang-jun HUANG Run-qiu 《山地科学学报:英文版》 SCIE CSCD 2019年第2期470-485,共16页
Silty sand can be prone to erosion because it is short of stability cementation materials. In recent years, various emerging soil stabilizers, especially natural organic substance and polymer, have been used to improv... Silty sand can be prone to erosion because it is short of stability cementation materials. In recent years, various emerging soil stabilizers, especially natural organic substance and polymer, have been used to improve soil strength, water stability and ability of erosion resistance. In this study, a new type of soil stabilization additive modified carboxymethyl cellulose(M-CMC), consisting of carboxymethyl cellulose(CMC) and polyacrylamide(PAM), was developed for stabilization treatment of silty sand. A series of laboratory tests were conducted to evaluate the performance of M-CMC application on shear strength, permeability, water susceptibility and microstructure of the silty sand soil treated with additive concentration range of 0%-1.3%. Moreover, rainfall simulation experiments were conducted to evaluate the effect of M-CMC on the erosion control of silty sand which compacted soil in a large-sized runoff(1 m~2) plots. Test plot which treated with 1.1% concentration of soil stabilizer and control plot which treated with same amount of water were cured outdoor for 50 days before rainfall simulation test. Rainfall intensity was applied at 120 mm·h-1 for 60 min. Finally, a field test is performed in order to assess the practical application effect of silty sand with 1.1% M-CMC. In general, the results showed that an increase of the concentration of M-CMC resulted in an improvement in water susceptibility and shear strength but a decrease in the infiltration rate. Internal friction angle of the treated soil remarkably increased under a low M-CMC concentration(less than 0.7%), while cohesion of them sharply increased under a relatively high M-CMC concentration(larger than 0.7%). Water susceptibility of the treated samples was improved remarkably under a relatively high M-CMC concentration(larger than 0.7%). Permeability coefficient of them decreased significantly when the M-CMC concentration was increased from 0 to 0.5% and, then, from 0.9% to 1.3%. Based on the images obtained from a scanning electron microscopy( 展开更多
关键词 Soil STABILIZATION WATER SUSCEPTIBILITY permeability EROSION WATER RETENTION CEMENTATION
Influence of reclaimed water discharge on the dissemination and relationships of sulfonamide, sulfonamide resistance genes along the Chaobai River, Beijing
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作者 Ning Zhang Xiang Liu +6 位作者 Rui Liu Tao Zhang Miao Li Zhuoran Zhang Zitao Qu Ziting Yuan Hechun Yu 《中国环境科学与工程前沿:英文版》 SCIE EI CAS CSCD 2019年第1期87-98,共12页
Reclaimed water represents an important source of antibiotics and antibiotic resistance genes, threatening the ecological safety of receiving environments, while alleviating water resource shortages. This study invest... Reclaimed water represents an important source of antibiotics and antibiotic resistance genes, threatening the ecological safety of receiving environments, while alleviating water resource shortages. This study investigated the dissemination of sulfonamide (SAs), sulfonamide resistance genes (SRGs), and class one integrons (intl1) in the surface water of the recharging area of the Chaobai River. The three antibiotics sulfamethoxazole, trimethoprim, and sulfadiazine had the highest abundance. The highest absolute abundances were 2.91×10^6, 6.94×10^6, and 2.18×10^4 copies/mL for sul1, sul2, and intl 1 at the recharge point, respectively. SRGs and intl1 were widespread and had high abundance not only at the recharging point, but also in remote areas up to 8 km away. Seasonal variations of SRGs abundance followed the order of summer>autumn>spring>winter. Significant correlations were found between SRGs and intl1 (a = 0.887 and 0.786, p<0.01), indicating the potential risk of SRGs dissemination. Strong correlations between the abundance of SRGs and environmental factors were also found, suggesting that appropriate environmental conditions favor the spread of SRGs. The obtained results indicate that recharging with reclaimed water causes dissemination and enrichment of SAs and SRGs in the receiving river. Further research is required for the risk assessment and scientific management of reclaimed water. 展开更多
关键词 SULFONAMIDE RESIDUES SULFONAMIDE resistance genes Reclaimed WATER RECHARGE Surface WATER Class one INTEGRONS
Evaluating mountain water scarcity on the county scale: a case study of Dongchuan District, Kunming, China
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作者 LI Jie DENG Wei ZHANG Ji-fei 《山地科学学报:英文版》 SCIE CSCD 2019年第4期744-754,共11页
Mountain water, which contributes 50% to 90% to the lower reaches of the watershed, has a considerably low utility efficiency. The water accessibility could be a quantitative measure of water scarcity in the mountains... Mountain water, which contributes 50% to 90% to the lower reaches of the watershed, has a considerably low utility efficiency. The water accessibility could be a quantitative measure of water scarcity in the mountains. It can be used effectively for emergency water shortage planning and water resource management. In the present study, Dongchuan District, a typical county in the Hengduan Mountains in Yunnan province of Southwest China, was selected as the study area, and the minimal cumulative resistance(MCR) model was used to simulate the least-cost path(LCP) from 1255 point features of natural villages, as well as 12,368 dryfield centroids, to their respective surrounding river systems, which serve as a source for emergency drinking water and irrigation during droughts. The average length of the LCP for each administrative village was calculated to represent the accessibility to water sources for agricultural production and daily life in these mountain villages. The distribution of population and dryfields, as well as other geographic elements, were analyzed to classify the degree of water scarcity in these villages. The results indicate that the area facing the highest risk of water shortage for agricultural irrigation is located in northern Dongchuan, in particular along the two sides of the Xiaojiang Valley, and that the area with the highest risk of water shortage for daily life needs is located along the Xiaojiang Valley. 展开更多
关键词 WATER SCARCITY MOUNTAINS WATER ACCESSIBILITY MCR model Dongchuan District
Geochemical evaluation of low salinity hot water injection to enhance heavy oil recovery from carbonate reservoirs
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作者 Ji Ho Lee Kun Sang Lee 《石油科学:英文版》 SCIE CAS CSCD 2019年第2期366-381,共16页
Although low salinity water injection(LSWI) has recovered residual oil after the conventional waterflood, highly viscous oil has remained in heavy oil reservoirs. Hot water injection is an economic and practical metho... Although low salinity water injection(LSWI) has recovered residual oil after the conventional waterflood, highly viscous oil has remained in heavy oil reservoirs. Hot water injection is an economic and practical method to improve oil mobility for viscous oil reservoirs. It potentially controls temperature-dependent geochemical reactions underlying the LSWI mechanism and oil viscosity. Therefore, this study has modeled and evaluated a hybrid process of low salinity hot water injection(hot LSWI) to quantify synergistic effects in heavy oil reservoirs. In comparison to seawater injection(SWI) and LSWI, hot LSWI results in more cation ion-exchange(Ca2+ and Mg2+) and more wettability modification. Hot LSWI also reduces oil viscosity. In core-scaled systems, it increases oil recovery by 21% and 6% over SWI and LSWI. In a pilotscaled reservoir, it produces additional oil by 6% and 3% over SWI and LSWI. Probabilistic forecasting with uncertainty assessment further evaluates the feasibility of hot LSWI to consider uncertainty in the pilot-scaled reservoir and observes enhanced heavy oil production. This study confirms the viability of hot LSWI due to synergistic effects including enhanced wettability modification and oil viscosity reduction effects. 展开更多
关键词 Low SALINITY WATER INJECTION Hot WATER INJECTION WETTABILITY modification GEOCHEMICAL reaction Viscosity reduction
干法氟化铝能源利用分析 预览
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作者 裴耀祖 李彩妍 唐惕 《云南化工》 CAS 2019年第1期96-97,99共3页
干法氟化铝生产工艺以流程短、工艺紧凑、原料利用率高、能耗低、环境污染少、产品质量好、市场竞争力强等特点而被广泛推广。然而,干法氟化铝在生产过程中,每天需要大量的新鲜水来提供系统的正常运行。但水资源为不可再生资源,全世界... 干法氟化铝生产工艺以流程短、工艺紧凑、原料利用率高、能耗低、环境污染少、产品质量好、市场竞争力强等特点而被广泛推广。然而,干法氟化铝在生产过程中,每天需要大量的新鲜水来提供系统的正常运行。但水资源为不可再生资源,全世界能被人类利用的淡水资源只占0.00768%。因此,做好水平衡工作,合理利用水资源迫在眉睫。 展开更多
关键词 干法氟化铝 水平衡
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超声波流量计在企业水平衡测试中的应用与分析 预览
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作者 王征 《科技风》 2019年第7期244-245,共2页
企业水平衡测试是实行工业节水的一项行之有效的基本方法。以一个化工企业为例,通过企业水平衡测试掌握企业厂区内各个单元具体用水情况。在水平衡测试工作中选用超声波流量计来协助测试工作,提升测试工作的效率与准确度,并同时优化了... 企业水平衡测试是实行工业节水的一项行之有效的基本方法。以一个化工企业为例,通过企业水平衡测试掌握企业厂区内各个单元具体用水情况。在水平衡测试工作中选用超声波流量计来协助测试工作,提升测试工作的效率与准确度,并同时优化了企业的节水长效管理。 展开更多
关键词 超声波 流量计 水平衡测试 工业节水
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Recent advances in thin film composites membranes for brackish groundwater treatment with critical focus on Saskatchewan water sources
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作者 Arash Mollahosseini Amira Abdelrasoul 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第7期181-194,共14页
Drinking water scarcity is an ever-increasing global concern. This issue appears as a greater threat to the countries with no access to sea water resources or rivers, since their potential water resources are only lim... Drinking water scarcity is an ever-increasing global concern. This issue appears as a greater threat to the countries with no access to sea water resources or rivers, since their potential water resources are only limited to ground waters only. There are serious concerns with the treatment of ground water resources, including landfill leachates, agricultural contaminations(pesticides,herbicides, and fertilizers), and rural contaminations. Membrane separation has been proved to be the governing technology in water and wastewater treatment plants, as these methods are responsible for more than half of the market share of the world’s desalination capacity. This study intends to offer a holistic view of the groundwater contamination with specific focus on Saskatchewan province in Canada, and the recent efforts in the groundwater treatment using thin film composite membrane technology. This study begins with an introduction of the general aspects of ground water and membrane separation, polluting agents, and their sources.It is followed by a discussion of Saskatchewan’s groundwater status and various issues.Furthermore, the recent research that became available since 2010 is reviewed in details and the results are summarized with respect to purification efficiency. Different affecting parameters in a groundwater-thin film composite system are synthesized and an in-depth overview is presented. 展开更多
关键词 Thin film composite membrane GROUNDWATER BRACKISH WATER WATER pollution POLYAMIDE CANADA SASKATCHEWAN
西葫芦微咸水膜下滴灌土壤水盐运移对产量影响的预测模型 预览
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作者 郭向红 毕远杰 +2 位作者 孙西欢 马娟娟 孔晓燕 《农业工程学报》 EI CAS CSCD 北大核心 2019年第8期167-175,共9页
为了定量计算微咸水膜下滴灌对土壤水盐和西葫芦产量的影响,根据微咸水膜下滴灌土壤水盐运移特点和西葫芦生长试验,建立了西葫芦微咸水膜下滴灌土壤水盐运移模型和水盐生产函数,并将二者联立,建立了西葫芦微咸水膜下滴灌土壤水盐运移对... 为了定量计算微咸水膜下滴灌对土壤水盐和西葫芦产量的影响,根据微咸水膜下滴灌土壤水盐运移特点和西葫芦生长试验,建立了西葫芦微咸水膜下滴灌土壤水盐运移模型和水盐生产函数,并将二者联立,建立了西葫芦微咸水膜下滴灌土壤水盐运移对产量影响的预测模型。利用西葫芦微咸水膜下滴灌水盐试验数据对模型进行验证,结果表明模型计算的西葫芦微咸水膜下滴灌土壤含水率和土壤含盐量与实测土壤含水率和土壤含盐量的变化趋势一致,模型计算土壤含水率、土壤含盐量和西葫芦产量的均方根误差分别为0.049 cm^3/cm^3、0.065 g/kg和3.83 t/hm^2,土壤含水率、土壤含盐量和西葫芦产量的平均相对误差分别为5.17%、7.42%和5.84%,土壤含水率、土壤含盐量和西葫芦产量的平均绝对误差分别为0.047 cm^3/cm^3、0.062 g/kg和3.95 t/hm^2。所建的模型具有较高的模拟精度,可用于模拟西葫芦微咸水膜下滴灌土壤水盐动态和西葫芦产量。 展开更多
关键词 土壤 产量 西葫芦 微咸水 膜下滴灌
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One-year survey of opportunistic premise plumbing pathogens and free-living amoebae in the tap-water of one northern city of China
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作者 Lizhong Liu Xueci Xing +1 位作者 Chun Hu Haibo Wang 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第3期20-31,共12页
In this study, qPCR was used to quantify opportunistic premise plumbing pathogens(OPPPs) and free-living amoebae in 11 tap water samples collected over four seasons from a city in northern China. Results demonstrated ... In this study, qPCR was used to quantify opportunistic premise plumbing pathogens(OPPPs) and free-living amoebae in 11 tap water samples collected over four seasons from a city in northern China. Results demonstrated that the average numbers of gene copies of Legionella spp. and Mycobacterium spp. were significantly higher than those of Aeromonas spp.(p < 0.05). Legionella spp. and Mycobacterium spp. were 100%(44/44) positively detected while P. aeruginosa and Aeromonas spp. were 79.54%(35/44) and 77.27%(34/44) positively detected. Legionella pneumophila was only detected in 4 samples(4/44), demonstrating its occasional occurrence. No Mycobacterium avium or Naegleria fowleri was detected in any of the samples. The average gene copy numbers of target OPPPs were the highest in summer,suggesting seasonal prevalence of OPPPs. Average gene copy numbers of OPPPs in the taps of low-use-frequency were higher than in taps of high-use-frequency, but the difference was not significant for some OPPPs(p > 0.05). Moderate negative correlations between the chlorine concentration and the gene copy numbers of OPPPs were observed by Spearman analysis(rsranged from -0.311 to -0.710, p < 0.05). However, no significant correlations existed between OPPPs and AOC, BDOC, or turbidity. Moderate positive correlations were observed between the target microorganisms, especially for Acanthamoeba spp., through Spearman analysis(p < 0.05). Based on our studies, it is proposed that disinfectant concentration, season, taps with different-use frequency, OPPP species, and potential microbial correlations should be considered for control of OPPPs in tap water. 展开更多
关键词 OPPORTUNISTIC premise PLUMBING pathogens(OPPPs) Free-living amoebae(FLA) Drinking WATER distribution systems(DWDS) Tap-water Quantitative PCR(qPCR)
An experimental study on the influences of water erosion on wind erosion in arid and semi-arid regions
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作者 YANG Huimin ZOU Xueyong +1 位作者 WANG Jing’ai SHI Peijun 《干旱区科学:英文版》 SCIE CSCD 2019年第2期208-216,共9页
Complex erosion by wind and water causes serious harm in arid and semi-arid regions. The interaction mechanisms between water erosion and wind erosion is the key to further our understanding of the complex erosion. Th... Complex erosion by wind and water causes serious harm in arid and semi-arid regions. The interaction mechanisms between water erosion and wind erosion is the key to further our understanding of the complex erosion. Therefore, in-depth understandings of the influences of water erosion on wind erosion is needed. This research used a wind tunnel and two rainfall simulators to investigate the influences of water erosion on succeeding wind erosion. The wind erosion measurements before and after water erosion were run on semi-fixed aeolian sandy soil configured with three slopes(5°, 10° and 15°), six wind speeds(0, 9, 11, 13, 15 and 20 m/s), and five rainfall intensities(0, 30, 45, 60 and 75 mm/h). Results showed that water erosion generally restrained the succeeding wind erosion. At a same slope, the restraining effects decreased as rainfall intensity increased, which decreased from 70.63% to 50.20% with rainfall intensity increased from 30 to 75 mm/h. Rills shaped by water erosion could weaken the restraining effects at wind speed exceeding 15 m/s mainly by cutting through the fine grain layer, exposing the sand layer prone to wind erosion to airflow. In addition, the restraining effects varied greatly among different soil types. The restraining effects of rainfall on the succeeding wind erosion depend on the formation of a coarsening layer with a crust and a compact fine grain layer after rainfall. The findings can deepen the understanding of the complex erosion and provide scientific basis for regional soil and water conservation in arid and semi-arid regions. 展开更多
关键词 WIND EROSION WATER EROSION SANDY soil particle size surface ROUGHNESS wind-water EROSION agriculturalpastoral ECOTONE
Spatial distribution of water-active soil layer along the south-north transect in the Loess Plateau of China
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作者 ZHAO Chunlei SHAO Ming’an +2 位作者 JIA Xiaoxu HUANG Laiming ZHU Yuanjun 《干旱区科学:英文版》 SCIE CSCD 2019年第2期228-240,共13页
Soil water is an important composition of water recycle in the soil-plant-atmosphere continuum.However, intense water exchange between soil-plant and soil-atmosphere interfaces only occurs in a certain layer of the so... Soil water is an important composition of water recycle in the soil-plant-atmosphere continuum.However, intense water exchange between soil-plant and soil-atmosphere interfaces only occurs in a certain layer of the soil profile. For deep insight into water active layer(WAL, defined as the soil layer with a coefficient of variation in soil water content >10% in a given time domain) in the Loess Plateau of China,we measured soil water content(SWC) in the 0.0–5.0 m soil profile from 86 sampling sites along an approximately 860-km long south-north transect during the period 2013–2016. Moreover, a dataset contained four climatic factors(mean annual precipitation, mean annual evaporation, annual mean temperature and mean annual dryness index) and five local factors(altitude, slope gradient, land use, clay content and soil organic carbon) of each sampling site was obtained. In this study, three WAL indices(WALT(the thickness of WAL), WAL-CV(the mean coefficient of variation in SWC within WAL) and WALSWC(the mean SWC within WAL)) were used to evaluate the characteristics of WAL. The results showed that with increasing latitude, WAL-T and WAL-CV increased firstly and then decreased. WAL-SWC showed an opposite distribution pattern along the south-north transect compared with WAL-T and WAL-CV.Average WAL-T of the transect was 2.0 m, suggesting intense soil water exchange in the 0.0–2.0 m soil layer in the study area. Soil water exchange was deeper and more intense in the middle region than in the southern and northern regions, with the values of WAL-CV and WAL-T being 27.3% and 4.3 m in the middle region,respectively. Both climatic(10.1%) and local(4.9%) factors influenced the indices of WAL, with climatic factors having a more dominant effect. Compared with multiple linear regressions, pedotransfer functions(PTFs) from arti?cial neural network can better estimate the WAL indices. PTFs developed by artificial neural network respectively explained 86%, 81% and 64% of the total variations in WAL-T, WAL-SWC and WAL-CV. K 展开更多
关键词 WATER ACTIVE layer soil WATER content REDUNDANCY analysis pedotransfer function artificial neural network LOESS Plateau
Fertirrigation with Low-Pressure Multi-Gate Irrigation Systems in Sugarcane Agroecosystems:A Review
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作者 Arturo GARC′IA-SALDA?NA Ces′areo LANDEROS-S′ANCHEZ +3 位作者 Mar′?a del Refugio CASTA?NEDA-CH′AVEZ Juan Pablo MART′INEZ-D′AVILA Arturo P′EREZ-V′AZQUEZ Eugenio CARRILLO-′AVILA 《土壤圈:英文版》 SCIE CAS CSCD 2019年第1期1-11,共11页
There are very few studies on the application of fertilizers through irrigation water(fertirrigation) using a multi-gate irrigation system in sugarcane AES. Through fertirrigation, the application of fertilizers can b... There are very few studies on the application of fertilizers through irrigation water(fertirrigation) using a multi-gate irrigation system in sugarcane AES. Through fertirrigation, the application of fertilizers can be simplified, and their distribution uniformity in sugarcane fields improved. This paper provides an overview of the state of the art regarding fertirrigation with multi-gate irrigation in sugarcane agroecosystems(AES). In order to systematize, organize, and discuss the scientific data on fertirrigation with low-pressure multi-gate irrigation systems in sugarcane AES, bibliographic material from the following full-text scientific journal databases was screened: the Elsevier Science Direct Freedom Collection, Springer Link, and the International Society for Horticultural Science. Next,a matrix of keywords was used to analyze the interrelationships among the available literature, current issues, and the recent findings.We conclude that development of fertirrigation technologies with low-pressure multi-gate irrigation is much needed. 展开更多
关键词 climate change crop WATER requirement FERTILIZER application FERTILIZER distribution UNIFORMITY SUGARCANE industry WATER use efficiency
Experimental study on unsaturated soil water diffusivity in different soils in Hebei Piedmont Plain 预览
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作者 GAO Ye-xin LIU Ji-chao +2 位作者 FENG Xin ZHANG Ying-ping ZHANG Bing 《地下水科学与工程:英文版》 2019年第2期165-172,共8页
Horizontal soil column method was used to determine the horizontal diffusion rate of sandy loam, loam and clay loam under the same bulk density. The results showed that the migration rates of different lithological we... Horizontal soil column method was used to determine the horizontal diffusion rate of sandy loam, loam and clay loam under the same bulk density. The results showed that the migration rates of different lithological wet fronts were different. The sandy loam had the fastest migration rate, the loam followed, and the clay loam was the slowest, but the law of change is the same among the three lithologies. The volumetric water content affects the change of Boltzmann parameter λ. When the volumetric water content is between 0.35-0.45 cm^3/cm^3,λ approaches stability. When the volumetric water content is less than 0.35 cm^3/cm^3, the λ value decreases rapidly with the decrease of water content. The water diffusion rate is related to the volumetric water content and particle size. The greater the moisture content is, the greater the diffusion rate will be. The larger the particle size, the larger the diffusion rate. The diffusivity of sandy loam is 10-30 times larger than that of loam and clay loam. The relationship between water content and diffusion rate is in accordance with the exponential function . 展开更多
关键词 Hebei PIEDMONT plain Soil WATER DIFFUSIVITY BOLTZMANN parameter VOLUMETRIC WATER content
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Comparative evaluation for catalytic gasification of petroleum coke and asphaltene in subcritical and supercritical water 预览
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作者 Rachita Rana Sonil Nanda +3 位作者 Aimee Maclennan Yongfeng Hu Janusz A. Kozinski Ajay K. Dalai 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第4期107-118,共12页
Subcritical and supercritical water gasification of petroleum coke and asphaltene was performed at variable temperatures (350-650℃),feed concentrations (15-30 wt%) and reaction times (15-60 min).Nickel-impregnated ac... Subcritical and supercritical water gasification of petroleum coke and asphaltene was performed at variable temperatures (350-650℃),feed concentrations (15-30 wt%) and reaction times (15-60 min).Nickel-impregnated activated carb on (Ni/AC) was synthesized as a catalyst for en hancing syngas yields at optimal gasification conditions (650℃,15 wt% and 60 min).Structural chemistry of precursors and chars developed at different gasification temperatures was studied using physicochemical and synchrotronbased approaches such as carbon-hydrogen-nitrogen-sulfur (CHNS) analysis,thermogravimetric and differential thermogravimetric analysis (TGA/DTA),scanning electron microscopy (SEM),Fourier-Transform Infrared spectroscopy (FTIR),Raman spectroscopy,X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS).Asphaltene testified to be a better precursor for catalytic hydrothermal gasification leading to 11.97 mmol/g of total gas yield compared to petroleum coke (8.04 mmol/g).In particular,supercritical water gasification using 5 wt% Ni/AC at 650℃ with 15 wt% feed concentration for 60 min resulted in 4.17 and 2.98 mmol/g of H2 from asphaltene and petroleum coke,respectively.Under the same conditions,the respective CH4 yields from catalytic gasification of asphaltene and petroleum coke were 2.54 and 1.07 mmol/g.Nonetheless,asphaltene also seemed to an attractive feedstock for the production of highly aromatic chars through hydrothermal gasification. 展开更多
关键词 ASPHALTENE Petroleum coke SUBCRITICAL WATER SUPERCRITICAL WATER GASIFICATION CHAR
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Temperature and silicate are significant driving factors for the seasonal shift of dominant diatoms in a drinking water reservoir 预览
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作者 ZHANG Yun PENG Chengrong +4 位作者 WANG Jun HUANG Shun HU Yao ZHANG Jinli LI Dunhai 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第2期568-579,共12页
The individual or combined eff ect of water temperature and silicate on seasonal shift of dominant diatom species in a drinking water reservoir in China was studied in this paper. These eff ects were analyzed based on... The individual or combined eff ect of water temperature and silicate on seasonal shift of dominant diatom species in a drinking water reservoir in China was studied in this paper. These eff ects were analyzed based on the field investigation of temporal dynamics in species composition and abundance of phytoplankton and environmental factors from September 2015 to August 2016. We firstly found that six dominant diatom species ( Fragilaria nanana , Achnanthidium catenatum , Aulacoseira ambigua , Ulnaria ulna , Cyclotella meneghiniana and Asterionella formosa (Class Bacillariophyceae)), which accounted for 98.7% of the total abundance of diatoms and 46.8% of the total abundance of phytoplankton, showed an obvious seasonal succession. Then significant driving factors for seasonal shift of the dominant diatom species were selected by Redundancy Analysis. The result showed that water temperature and silicate were the main environmental factors aff ecting the growth of diatoms on temporal scales. Next, the regressions of water temperature and silicate and dominant diatom abundance were fitted in Generalized Additive Model separately, and the smoothers of water temperature and diatom species suggested that the dominant diatom species adapted to diff erent optimum temperature ranges, which corresponded with the growth of seasonal changes. A positive linear correlation between silicate and diatom abundance was generated by Generalized Additive Model. Finally, the ordinal controls of water temperature and silicate on the growth of diatoms were analyzed on temporal scales specifically. We suggested that water temperature and silicate controlling the growth of diatoms in order. Diatoms grow well only when the two controlling factors simultaneously satisfy the growth conditions;as limiting factors, the two factors played their respective limiting roles in turn on temporal scales. 展开更多
关键词 DIATOM drinking WATER RESERVOIR seasonal succession SILICATE WATER TEMPERATURE
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河流静水滩区潜流带水交换空间分布模式研究(英文)
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作者 宋进喜 程丹东 +4 位作者 张军龙 张永强 龙永清 张妍 申卫博 《地理学报:英文版》 SCIE CSCD 2019年第3期377-388,共12页
Hyporheic zone(HZ) influences hydraulic and biogeochemical processes in and alongside streams, therefore, investigating the controlling geographic factors is beneficial for understanding the hydrological processes in ... Hyporheic zone(HZ) influences hydraulic and biogeochemical processes in and alongside streams, therefore, investigating the controlling geographic factors is beneficial for understanding the hydrological processes in HZ. Slack water pool (SWP) is an essential micro-topographic structure that has an impact on surface water and groundwater interactions in the HZ during and after high flows. However, only a few studies investigate HZ surface water and groundwater exchange in the SWP. This study used the thermal method to estimate the HZ water exchange in the SWP in a segment of the Weihe River in China during the winter season. The findings show that on the flow-direction parallel to the stream, river recharge dominates the HZ water exchange, while on the opposing flow-direction bank groundwater discharge dominates the water exchange. The water exchange in the opposing flow-direction bank is about 1.6 times of that in the flow-direction bank. The HZ water exchange is not only controlled by flow velocity but also the location and shape of the SWP. Great water exchange amount corresponds to the shape with more deformation. The maximum water exchange within the SWP is close to the river bank where the edge is relatively high. This study provides some guidelines for water resources management during flooding events. 展开更多
关键词 HYPORHEIC WATER exchange thermal method discharge RECHARGE surface water-groundwater interactions
Single-crystal TiO2/SrTiO3 core–shell heterostructured nanowire arrays for enhanced photoelectrochemical performance
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作者 Ying Chen Shi Li +3 位作者 Ruo-Yu Zhao Wei Li Zhao-Hui Ren Gao-Rong Han 《稀有金属:英文版》 SCIE EI CAS CSCD 2019年第5期369-378,共10页
Vertically aligned TiO2/SrTiO3 core–shell heterostructured nanowire arrays with different shell thicknesses(5–40 nm)were fabricated on fluorine-doped tin oxide substrate via a hydrothermal process.Microstructural ch... Vertically aligned TiO2/SrTiO3 core–shell heterostructured nanowire arrays with different shell thicknesses(5–40 nm)were fabricated on fluorine-doped tin oxide substrate via a hydrothermal process.Microstructural characterization demonstrated that the TiO2 nanowires were uniformly coated by the singlecrystal SrTiO3 shell,where continuous and large-area interface could be clearly observed.By this means,significantly enhanced photoelectrochemical water splitting properties(0.78 mA·cm^-2 at 1.23 V vs.RHE)were successfully realized in well-designed sample(with a shell thickness of 5–10 nm)compared with those of pristine TiO2(0.38 mA·cm^-2 at 1.23 V vs.RHE).The improvement of photoelectrochemical properties was attributed to the improved charge injection and charge separation,which are calculated by the results of water oxidation and sulfite oxidation measurements.Based on these results,a mechanism was proposed that SrTiO3 shell acted as an electron–hole separation layer to improve the photocurrent density.On the other hand,the sample with an over-thick SrTiO3 shell(20–40 nm)exhibited slightly reduced photoelectrochemical properties(0.66 mA·cm^-2),which could be explained by the increase of the recombination rate in thethicker SrTiO3 shell.This work provided a facile strategy to improve and modulate the photoelectrochemical performance of heterostructured photoanodes. 展开更多
关键词 TiO2/SrTiO3 heterostructured nanowire arrays PHOTOELECTROCHEMICAL water splitting SHELL thickness Band alignment
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