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Integrated Assessment of Trapping Efficiency of Colored Sticky Cards and Sex Pheromone on Liriomyza spp.and Plutella xylostella 被引量:2
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作者 陈祯 郑传伟 +3 位作者 陈旷 戈毅航 刘霞 况荣平 《Agricultural Science & Technology》 CAS 2015年第2期306-310,共5页
[Objective] To evaluate the control effect of yellow sticky cards and sex pheromone on Plutella xylostella and Liriomyza spp.,which can provide reference for large area extension of the technique.[Method] The integrat... [Objective] To evaluate the control effect of yellow sticky cards and sex pheromone on Plutella xylostella and Liriomyza spp.,which can provide reference for large area extension of the technique.[Method] The integrated assessment of trapping efficiency of colored sticky cards and sex pheromone on Liriomyza spp.and Plutella xylostella was conducted by field surveys and structured interview in Tonghai County,Yunnan Province,China.[Result] The results showed that yellow sticky cards and sex pheromone have strong power of trapping Liriomyza spp.and Plutella xylostella(3 414±720 and(219±157) head/piece,respectively);the control cost by the usage of pesticide is the highest,(10 099.5±2 752.5) yuan/hm^2,yellow sticky cards and sex pheromone takes the second place,(1 125.0±465.0) yuan/hm^2,the control cost by the usage of yellow sticky cards is the lowest,(450.0 ±186.0)yuan/hm^2.Without the usage of yellow sticky cards and sex pheromone,pesticide application times and costs are(15.0±2.7) times and(12 070.5±2 136.0) yuan/hm^2;combined with usage of yellow sticky cards and sex pheromone,pesticide application times and costs reduce by 5.7 times and 4 618.5 yuan/hm^2.The ratio of trapped beneficial insects and target pests was 1 ∶1 131,which showed that the negative effect of yellow sticky cards and sex pheromone on the non-target insects was very limited.[Conclusion] The trapping approach has become popular among all the local farmers.Looking at the above factors,the trapping technology has strong application prospect and promotion value in pest control field. 展开更多
关键词 Yellow sticky cards Sex pheromone Liriomyza spp. Plutella xylostella Integrated assessment Ecological impact trapping efficiency Application prospect
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Theoretical study of the trapping efficiency of an optical tweezers array system 被引量:5
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作者 李勤 冯万力 +3 位作者 胡晓明 曹群 沙定国 林家明 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第2期726-735,共10页
Optical tweezers have been a valuable research tool since their invention in the 1980s. One of the most important developments in optical tweezers in recent years is the creation of two-dimensional arrays of optical t... Optical tweezers have been a valuable research tool since their invention in the 1980s. One of the most important developments in optical tweezers in recent years is the creation of two-dimensional arrays of optical traps. In this paper, a method based on interference is discussed to form gradient laser fields, which may cause the spatial modulation of particle concentration. The parameters related to the optical tweezers array are discussed in detail and simulated by the Matlab software to show the influence of important parameters on the distribution of particle concentration. The spatial redistribution of particles in a laser interference field can also be predicted according to the theoretical analysis. 展开更多
关键词 optical tweezers array gradient force trapping efficiency spatial modulation
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Species- and Habitat-variability of Photosynthesis, Transpiration and Water Use Efficiency of Different Plant Species in Maowusu Sand Area 被引量:105
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作者 蒋高明 何维明 《Acta Botanica Sinica》 CSCD 1999年第10期1114-1124,共11页
Photosynthesis ( P n ), transpiration ( E ) and water use efficiency ( WUE ) of more than 66 arid sand species from different environmental habitats, shifting sand dune, fixed sand dune, lowland and wetland in ... Photosynthesis ( P n ), transpiration ( E ) and water use efficiency ( WUE ) of more than 66 arid sand species from different environmental habitats, shifting sand dune, fixed sand dune, lowland and wetland in the Maowusu Sand Area were analyzed and the relation among these characteristics and the resource utilization efficiency, taxonomic categories and growth forms of the species were assessed. The results showed that species from Chenopodiaceae, Gramineae, Leguminosae which possessed the C 4 photosynthesis pathway, or C 3 pathway and also with nitrogen_fixation capacities had higher or the highest P n values, i.e., 20~30 μmol CO 2·m -2 ·s -1 , while that of evergreen shrub of Pinaceae had the lowest P n values, i.e., 0~5 μmol CO 2·m -2 ·s -1 . Those species from Compositae, Scrophulariaceae, and Gramineae with C 3 pathway but no N_fixation capacity had the highest E rates, i.e., 20~30 mmol H 2O·m -2 ·s -1 and again the evergreen shrub together with some species from Salicaceae and Compositae had the lowest E rates, i.e., 0~5 mmol H 2O·m -2 ·s -1 . Species from Leguminosae, Gramineae and Chenopodiaceae with C 4 pathway or C 3 pathway with N_fixation capacity, both shrubs and grasses, generally had higher WUE . However, even the physiological traits of the same species were habitat_ and season_specific. The values of both P n and E in late summer were much higher than those in early summer, with average increases of 26%, 40% respectively in the four habitats. WUE in late summer was, however, 12% lower. Generally, when the environments became drier as a result of habitats changed, i.e., in the order of wetland, lowland, fixed sand dune and shifting sand dune, P n and E decreased but WUE increased. 展开更多
关键词 PHOTOSYNTHESIS TRANSPIRATION Water use efficiency HABITAT C 4 pathway SHRUBS Grasses Maowusu sand Area
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3D CFD validation of invert trap efficiency for sewer solid management using VOF model 被引量:5
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作者 Mohammad Mohsin Deo Raj Kaushal 《Water Science and Engineering》 EI CAS CSCD 2016年第2期106-114,共9页
Earlier investigators have numerically carried out performance analysis of the invert trap fitted in an open channel using the stochastic discrete phase model(DPM) by assuming the open channel flow to be closed condui... Earlier investigators have numerically carried out performance analysis of the invert trap fitted in an open channel using the stochastic discrete phase model(DPM) by assuming the open channel flow to be closed conduit flow under pressure and assuming zero shear stress at the top wall.This is known as the fixed lid model.By assuming the top wall to be a shear free wall,they have been able to show that the velocity distribution looks similar to that of an open channel flow with zero velocity at the bottom and maximum velocity at the top,representing the free water surface,but no information has been provided for the pressure at the free water surface.Because of this assumption,the validation of the model in predicting the trap efficiency has performed significantly poorly.In addition,the free water surface subject to zero gauge pressure cannot be modeled using the fixed lid model because there is no provision of extra space in the form of air space for the fluctuating part of the water surface profile.It can.however,be modeled using the volume of fluid(VOF) model because the VOF model is the appropriate model for open channel or free surface flow.Therefore,in the present study,three-dimensional(3D) computational fluid dynamics(CFD) modeling with the VOF model,which considers open channel flow with a free water surface,along with the stochastic DPM.was used to model the trap efficiency of an invert trap fitted in an open rectangular channel.The governing mathematical flow equations of the VOF model were solved using the ANSYS Fluent 14.0 software,reproducing the experimental conditions exactly.The results show that the 3D CFD predictions using the VOF model closely fit the experimental data for glass bead particles. 展开更多
关键词 Computational FLUID dynamics (CFD) Sediment deposition trap efficiency Invert trap Volume of FLUID (VOF) model
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Adiabatic cooling for cold polar molecules on a chip using a controllable high-efficiency electrostatic surface trap 被引量:6
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作者 李胜强 许亮 +2 位作者 夏勇 汪海玲 印建平 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第12期148-154,共7页
We propose a controllable high-efficiency electrostatic surface trap for cold polar molecules on a chip by using two insulator-embedded charged rings and a grounded conductor plate. We calculate Stark energy structure... We propose a controllable high-efficiency electrostatic surface trap for cold polar molecules on a chip by using two insulator-embedded charged rings and a grounded conductor plate. We calculate Stark energy structure pattern of ND3 molecules in an external electric field using the method of matrix diagonalization. We analyze how the voltages that are applied to the ring electrodes affect the depth of the efficient well and the controllability of the distance between the trap center and the surface of the chip. To obtain a better understanding, we simulate the dynamical loading and trapping processes of ND3 molecules in a |J, KM = |1,-1 state by using classical Monte–Carlo method. Our study shows that the loading efficiency of our trap can reach ~ 88%. Finally, we study the adiabatic cooling of cold molecules in our surface trap by linearly lowering the potential-well depth(i.e., lowering the trapping voltage), and find that the temperature of the trapped ND3 molecules can be adiabatically cooled from 34.5 m K to ~ 5.8 m K when the trapping voltage is reduced from-35 k V to-3 k V. 展开更多
关键词 CONTROLLABLE high-efficiency surface trap cold polar molecules
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Monitoring and Evaluating the Sedimentation Process in Mosul Dam Reservoir Using Trap Efficiency Approaches 被引量:1
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作者 Issa E. Issa Nadhir Al-Ansari +1 位作者 Sven Knutsson Govand Sherwany 《Engineering(科研)》 2015年第4期190-202,共13页
Reservoirs are usually exposed to sediment accumulation problems that will lead to reduction in their storage capacity. This problem directly affects the performance of the dams and causes shortage of their useful lif... Reservoirs are usually exposed to sediment accumulation problems that will lead to reduction in their storage capacity. This problem directly affects the performance of the dams and causes shortage of their useful life. The simplest technique to estimate sediment deposition rate is using sediment rating curve with sediment trapping efficiency (TE) of the reservoir. Many empirical and semi-empirical approaches have been suggested for to determine this term depending on the annual inflow rate, reservoir characteristics and features of the catchments area. In this study six different empirical methods depending on the residence time principle (water retention time) were used. These approaches were reviewed and applied to determine TE of Mosul dam reservoir (MDR) for period 1986 to 2011. The monthly operating data for inflow, outflow and water elevations for MDR were used to determine monthly TE and long-term TE for whole period of MDR using the mentioned methods. Furthermore, the monthly inflow rate for River Tigris upstream MDR, its sediment rating curve and sediment feeding from valleys around MDR were used to estimate the amount sediment coming to the reservoir. The results provided by these methods for TE with sediment coming to MDR were used to compute the amount of sediment deposited in MDR on monthly bases during this period. The results obtained were evaluated using observed bathymetric survey data that had been collected in 2011 after 25 years of the operation of the dam. The results showed all the mentioned methods gave convergent results and they were very close to bathymetric survey results for estimating the volume of sediment deposited especially that proposed by Ward which gave 0.368% percentage error. Furthermore, the result computed using monthly TE gave good agreement if compared with that long-term TE where the percentage error was ranging between –3.229% to 1.674% for monthly adopted data and –4.862% to?–2.477% for whole period data. It is believed that this work will help others to use this procedure on other reservoirs. 展开更多
关键词 Losing Storage Capacity Mosul DAM RESERVOIR SEDIMENTATION SEDIMENT trap efficiency
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Numerical simulation on sand sedimentation and erosion characteristics around HDPE sheet sand barrier under different wind angles 被引量:1
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作者 ZHANG Kai ZHANG Peili +3 位作者 ZHANG Hailong TIAN Jianjin WANG Zhenghui XIAO Jianhua 《Journal of Mountain Science》 SCIE CSCD 2024年第2期538-554,共17页
For the safety of railroad operations,sand barriers are utilized to mitigate wind-sand disaster effects.These disasters,characterized by multi-directional wind patterns,result in diverse angles among the barriers.In t... For the safety of railroad operations,sand barriers are utilized to mitigate wind-sand disaster effects.These disasters,characterized by multi-directional wind patterns,result in diverse angles among the barriers.In this study,using numerical simulations,we examined the behavior of High Density Polyethylene(HDPE)sheet sand barriers under different wind angles,focusing on flow field distribution,windproof efficiency,and sedimentation erosion dynamics.This study discovered that at a steady wind speed,airflow velocity varies as the angle between the airflow and the HDPE barrier changes.Specifically,a 90°angle results in the widest low-speed airflow area on the barrier’s downwind side.If the airflow is not perpendicular to the barrier,it prompts a lateral airflow movement which decreases as the angle expands.The windproof efficiency correlates directly with this angle but inversely with the wind’s speed.Notably,with a wind angle of 90°,wind speed drops by 81%.The minimum wind speed is found at 5.1H(the sand barrier height)on the barrier’s downwind side.As the angle grows,the barrier’s windproof efficiency improves,extending its protective reach.Sedimentation is most prominent on the barrier’s downwind side,as the wind angle shifts from 30°to 90°,the sand sedimentation area on the barrier’s downwind side enlarges by 14.8H.As the angle grows,sedimentation intensifies,eventually overtakes the forward erosion and enlarges the sedimentation area. 展开更多
关键词 Multi-wind direction HDPE sheet sand barrier Numerical simulation Windproof efficiency Sedimentation erosion
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A Fast Predicting Neural Fuzzy Model for Suspended Solid Removal Efficiency in Multimedia Filter
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作者 Rusul Naseer Alaa' Abdulrazaq Jassim Saad AbuAlhail 《Journal of Environmental Protection》 2010年第4期438-447,共10页
Modeling of filter performance is very difficult because of complexity of the defining physical and chemical events in the filtration system whereas the knowledge of functionality of filter coefficient. The main objec... Modeling of filter performance is very difficult because of complexity of the defining physical and chemical events in the filtration system whereas the knowledge of functionality of filter coefficient. The main objective of this study is to predict the performance of multimedia filter and to evaluate both the initial and transient stage of suspended solid removal efficiency depending on experimental data. Fuzzy logic has been used to build a model of multi input and one output (MISO) for the removal efficiency of multimedia filter which it consists from sand and granular activated carbon (GAC) mediums. The control parameters of (FLC) of Sugeno model are seven parameters which are media depths, media grains size for both sand and GAC, filtration rate, diameter of suspension particle, feed concentration, and operation time. The output parameter is removal efficiency of media filter whereas these data are collocated from pilot scale deep bed filter, thus, the removal efficiency of filter was modeled by 575 rules as a function of different control parameters. An adaptive of neuron fuzzy inference system (ANFIS) had used to simulate the experimental data. The simulation results were evaluated using mean absolute percentage error (MAPE), whereas the results showed that the prediction of ANFIS model has a good agreement with experimental data when the MAPE is equal to 7.0458 and fuzzy rule -based modeling proved a reliable and flexible tool to study the performance of multimedia filter. The conclusion showed that there is a relationship between flow rate, effective size and optimum bed depth for all filter media, the increment of effective size generates a higher value of optimum filter bed depth for a lower value of filtration rate. It was concluded that the optimal removal efficiency (95-100) achieved by (0.5-0.7 mm) grain size of sand, (1.5-1.9) mm grain size of granular activated carbon (GAC), with media depths should range from 0.3 to 0.6 m. 展开更多
关键词 MULTIMEDIA Filter sand FILTRATION REMOVAL efficiency Fuzzy LOGIC Suspended SOLID
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Effect of Two Substrate Types on Feeding Efficiency by Juvenile Chinese Sturgeon Acipenser sinensis on Barcheek Goby Rhinogobius giurinus
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作者 Xiaolian Gu Jianyi Liu +5 位作者 Sikai Wang Tao Zhang Feng Zhao Ping Zhuang Ming Duang Boyd Kynard 《Agricultural Sciences》 2023年第10期1436-1443,共8页
We conducted experiments in an artificial stream tank with wild juvenile Chinese sturgeon Acipenser sinensis captured in the Yangtze Estuary to test the null hypothesis that their feeding efficiency on Barcheek goby R... We conducted experiments in an artificial stream tank with wild juvenile Chinese sturgeon Acipenser sinensis captured in the Yangtze Estuary to test the null hypothesis that their feeding efficiency on Barcheek goby Rhinogobius giurinus was not affected by sand vs. smooth glass substrate. Gobies are among the most common prey eaten by wild juvenile A. sinensis in the estuary. Test results found neither substrate type significantly affected feeding efficiency by juveniles. Previous research found a strong innate habitat preference of A. sinensis for sand substrate. The present results indicate that the preference for sand is not related to efficiently capturing R. giurinus on sand, but is an adaptation predisposing juvenile A. sinensis to seek sandy substrate where R. giurinus and other benthic forage are the most abundant in the Yangtze Estuary. 展开更多
关键词 Acipenser sinensis Feeding efficiency sand Substrate BEHAVIOR
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Distribution and controls of petroliferous plays in subtle traps within a Paleogene lacustrine sequence stratigraphic framework, Dongying Depression, Bohai Bay Basin, Eastern China 被引量:2
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作者 Ji-Chang Zhu Cai-Neng Zou +4 位作者 You-Liang Feng Shu Jiang Wei-An Wu Ri-xiang Zhu Miao Yuan 《Petroleum Science》 SCIE CAS CSCD 2020年第1期1-22,共22页
The characteristics of petroliferous plays in subtle traps within a sequence stratigraphic framework in the Dongying Depression are investigated in this study.Sand bodies within lowstand systems tracts(LSTs)of sequenc... The characteristics of petroliferous plays in subtle traps within a sequence stratigraphic framework in the Dongying Depression are investigated in this study.Sand bodies within lowstand systems tracts(LSTs)of sequences,comprising incisedchannel fills,sublacustrine fans,deltas in LSTs,controlled by syndepositional normal faults,and sand bodies within transgressive systems tracts(TSTs)to early highstand systems tracts(HSTs),consisting of beach bars,and turbidites,controlled by the prodelta slope,paleorelief,and syndepositional normal faults,are good subtle reservoirs.Mudstones and shale of deep lake subfacies in TSTs to early HSTs of sequences are source and cap rocks.Abnormal overpressure is the dominant dynamic factor for hydrocarbon migration from source rock to the subtle traps.Normal faults,sand bodies,and unconformities function as conduit systems.Sand bodies distributed in the abnormal overpressure source rocks within LSTs to early HSTs are petroliferous plays in lithologic traps.The petroliferous plays in stratigraphic traps are controlled by unconformities at margins of the Depression. 展开更多
关键词 Subtle traps sand bodies WITHIN lowstand systems TRACT Syndepositional normal fault Abnormal OVERPRESSURE Dongying Depression
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Optimization of a magneto–optic trap using nanofibers 被引量:2
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作者 Xin Wang Li-Jun Song +3 位作者 Chen-Xi Wang Peng-Fei Zhang Gang Li Tian-Cai Zhang 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第7期198-201,共4页
We experimentally demonstrate a reliable method based on a nanofiber to optimize the number of cold atoms in a magneto–optical trap(MOT) and to monitor the MOT in real time.The atomic fluorescence is collected by a n... We experimentally demonstrate a reliable method based on a nanofiber to optimize the number of cold atoms in a magneto–optical trap(MOT) and to monitor the MOT in real time.The atomic fluorescence is collected by a nanofiber with subwavelength diameter of about 400 nm.The MOT parameters are experimentally adjusted in order to match the maximum number of cold atoms provided by the fluorescence collected by the nanofiber.The maximum number of cold atoms is obtained when the intensities of the cooling and re-pumping beams are about 23.5 mW/cm^2 and 7.1 mW/cm^2,respectively;the detuning of the cooling beam is-13.0 MHz, and the axial magnetic gradient is about 9.7 Gauss/cm.We observe a maximum photon counting rate of nearly(4.5 ± 0.1)× 10^5 counts/s.The nanofiber–atom system can provide a powerful and flexible tool for sensitive atom detection and for monitoring atom–matter coupling.It can be widely used from quantum optics to quantum precision measurement. 展开更多
关键词 NANOFIBER magneto–optic trap OPTIMIZATION fluorescence efficient coupling
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Hydrogel amendment to sandy soil reduces irrigation frequency and improves the biomass of Agrostis stolonifera 被引量:1
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作者 Hillary Agaba Lawrence J. B. Orikiriza +3 位作者 Joseph Obua John. D. Kabasa Martin Worbes Aloys Hüttermann 《Agricultural Sciences》 2011年第4期544-550,共7页
Soil water potential indicates the water status of the soil and the need for irrigation. The effect of hydrogel amendment to the upper sand soil layer on water infiltration into the lower un-amended sand layer, irriga... Soil water potential indicates the water status of the soil and the need for irrigation. The effect of hydrogel amendment to the upper sand soil layer on water infiltration into the lower un-amended sand layer, irrigation frequency, water use efficiency and biomass production of Agrostis stolonifera was investigated. The upper 25 cm sand layer in three identical buckets was amended at 0.4%, 0.2% and a control (no hydrogel) while the lower 25 cm sand layer separated from the upper layer by a wire mesh in the same buckets was un-amended. Agrostis stolonifera seeds were sown in each bucket and adequately irrigated using a hand sprayer. Potential meter electrodes were inserted at three random positions in each of the buckets and subsequent irrigations were done when a pressure of 600 bars was recorded in any of the three treatments. Data were collected on irrigation frequency, water content in the lower layer, water use efficiency and biomass production of Agrostis stolonifera. The mean water potential in the lower 25 cm layer un-amended sand was significantly more negative in the 0.4% hydrogel than in the control. More water content (10%) was recorded in the lower layer under the control bucket than in either the 0.2% and 0.4% hydrogel amended buckets. The frequency of irrigation was three-fold in the control compared to the 0.4% hydrogel amended sand. The hydrogel amended sand significantly increased the shoot and root biomass of Agrostis stolonifera by 2.2 and 4 times respectively compared to the control. The 0.4% hydrogel amendment in sand increased the water use efficiency of grass eight fold with respect to the control. The hydrogel stimulated development of a dense root network and root aggregation that increased contact of the roots with moisture thus improving water use efficiency of hydrogel amended soil. The results suggest that hydrogels can improve sandy soil properties for plant growth by absorbing and keeping water longer in the soil matrix thus reducing watering frequency. 展开更多
关键词 sand Water Use efficiency HYDROGEL IRRIGATION BIOMASS AGROSTIS Stolonifera
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How Can China Avoid The "Low-to-Moderate Income Trap"? 被引量:1
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作者 蔡昉 《China Economist》 2008年第2期108-115,共8页
At present, China finds itself at a crucial moment of development. Economic growth should embody the requirement of "sound and fast" development, whose prerequisite should be reasonable and orderly income di... At present, China finds itself at a crucial moment of development. Economic growth should embody the requirement of "sound and fast" development, whose prerequisite should be reasonable and orderly income distribution. Theory and the experience of other countries show that when making the transformation from a moderate to high income society, wide income distribution discrepancies may hinder economic growth. To avoid falling into this trap, China needs to strike a balance between utilizing both market mechanisms and government regulation to achieve a "fair" and "efficient" income balance during the rudimentary and redistribution phase. 展开更多
关键词 INCOME distribution INCOME trap efficiency Fair.
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Did Ecological Engineering Projects Have a Significant Effect on Large-scale Vegetation Restoration in Beijing-Tianjin Sand Source Region, China? A Remote Sensing Approach 被引量:6
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作者 LI Xiaosong WANG Hongyan +2 位作者 ZHOU Shufang SUN Bin GAO Zhihai 《Chinese Geographical Science》 SCIE CSCD 2016年第2期216-228,共13页
Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation re... Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation restoration in the Beijing-Tianjin Sand Source Region(BTSSR) from 2000 to 2010 based on the rain use efficiency(RUE) trend in relation to the land cover. More than half of the BTSSR experienced a vegetation productivity increase from 2000 to 2010, with the increasing intensity being sensitive to the indicators chosen. A clear tendency towards smaller increasing areas was shown when using the net primary productivity(NPP, 51.30%) instead of the accumulated normalized difference vegetation index(59.30%). The short-term variation in the precipitation and intra-seasonal precipitation distribution had a great impact on the remote sensing-based vegetation productivity. However, the residual trends method(RESTREND) effectively eliminated this correlation, while incorporating the variance and skewness of the precipitation distribution increased the models′ ability to explain the vegetation productivity variation. The RUE combined with land cover dynamics was valid for the effectiveness assessment of the ecological engineering projects on vegetation restoration. Particularly, the result based on growing season accumulated normalized difference vegetation index(ΣNDVI) residuals was the most effective, showing that 47.39% of the BTSSR experienced vegetation restoration from 2000 to 2010. The effectiveness of the ecological engineering projects differed for each subarea and was proportional to the strength of ecological engineering. The water erosion region dominated by woodland showed the best restoration, followed by the wind-water erosion crisscross regions, while the wind erosion regions dominated by grassland showed the worst effect. Seriously degraded regions still cover more area in the BTSSR than restored regions. Therefore, more future effort should be put in restoring degraded land. 展开更多
关键词 vegetation restoration ecological engineering rain use efficiency(RUE) residual trends method(RESTREND) Beijing-Tianjin sand Source Region(BTSSR)
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Experimental Study on Improvement of Soft Clay Using Sand Columns
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作者 N.Sohaib M.SarfrazFaiz M.Farjad Sami 《Journal of Civil Engineering and Architecture》 2020年第7期391-401,共11页
Sand Compaction Piles(SCP)commonly known as Sand Columns(SC)now has been vastly used for reinforcing the range of soft soils.The installation of sand columns results in enhancing the ultimate bearing capacity of soft ... Sand Compaction Piles(SCP)commonly known as Sand Columns(SC)now has been vastly used for reinforcing the range of soft soils.The installation of sand columns results in enhancing the ultimate bearing capacity of soft soil,increase the rate of consolidation,prevention of liquefaction in loose sandy soils and provide lateral resistance against the horizontal movement.This research aims at investigating the effects of floating columns in clayey soil with silty deposits by developing small scale laboratory models.The laboratory tests were conducted on a circular column of 37 mm diameter and results of the treated ground are compared to the untreated ground.The effects of sand columns on soils of different shear strengths(low-medium-high),slenderness ratio(L/D)of columns and different loading pattern are investigated.Group effect was also investigated by varying the spacing between the columns.The equivalent entire area of test model was loaded to determine the stiffness of composite ground and axial capacity of sand column was determined by loading the column area alone.Based on current study,it was concluded that sand column can significantly enhance the engineering properties of soft clayey soil.Also,the group effect was studied and it was concluded that by increasing the spacing between the columns,the group efficiency decreases.The axial capacity of sand columns decreases while increasing the spacing between the columns. 展开更多
关键词 Ground IMPROVEMENT sand COLUMNS SHEAR strength SLENDERNESS ratio group efficiency
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Production and Evaluation of Synthetic Carbonated Sand as an Adsorbent Media for Batch Adsorption Process
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作者 Rafa Hashim A1-Suhaili Diheyaa Waj id Abbood Haider Ali Mehdi 《Journal of Environmental Science and Engineering(A)》 2013年第7期453-463,共11页
An attempt was made to improve the adsorption capability of the normal sand to be used as adsorbent for phenol and cadmium This has been done by producing a coated sand media. The coating process was done using emulsi... An attempt was made to improve the adsorption capability of the normal sand to be used as adsorbent for phenol and cadmium This has been done by producing a coated sand media. The coating process was done using emulsion asphalt to convert the normal sand to carbonated sand by using chemical treatment with sulfuric acid. The production process involves mixing of the sand with asphalt and an acid, then subjecting the mix to a heating process. Different mixing ratios, heating temperatures and times (activation times) were tried to obtain the optimum conditions at which the highest removal efficiency is obtained. Three types of acids were tried acetic acid, phosphoric acid and sulfuric acid. It was found that the sulfuric acid requires the lowest activation time, hence selected for the production. The removal efficiency of the produced media was significantly affected by the temperature, mixing ratio and activation heating time. The results show that, the optimum conditions for the production process are 350 , (1:2:3) (Asphalt/acid/sand) and 52 min for temperature, mixing ratio and activation heating time respectively. The final product was tested and found effective as an adsorbent media for phenol and cadmium. The removal efficiencies of these two pollutants in a batch adsorber were found 82.42% and 86.67%, respectively. The X-R diffraction and FTIR spectra tests had proved this media as an adsorbent. 展开更多
关键词 Carbonated sand adsorbent media organic and inorganic emulsion asphalt optimum conditions mixing ratio activation time removal efficiency.
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铁路三维电子沙盘搭建及其应用研究 被引量:1
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作者 赵亮亮 董凤翔 黄旎诗 《铁道标准设计》 北大核心 2024年第8期50-57,共8页
为解决目前铁路行业电子沙盘存在的表达方式不一、应用内容单一、数据泄露风险大、数据加载效率低等问题,研究海量地理地质及BIM模型的数据处理、管理和应用方法,建立以BIM+GIS为技术核心的标准化电子沙盘,从而更好地服务于铁路设计和... 为解决目前铁路行业电子沙盘存在的表达方式不一、应用内容单一、数据泄露风险大、数据加载效率低等问题,研究海量地理地质及BIM模型的数据处理、管理和应用方法,建立以BIM+GIS为技术核心的标准化电子沙盘,从而更好地服务于铁路设计和建造。根据鲁南高铁、拉林铁路、成渝中线高铁等项目实践总结,在中国铁路BIM联盟和国铁集团相关标准基础上提出了面向电子沙盘应用的地形、影像、BIM模型、专题图的数据制作标准,从坐标转换、数据转换、数据切片、知识图谱建立、模型发布、前端数据汇集的方法完成了电子沙盘的搭建。最后,在电子沙盘中实现了百公里级、多专业数据的在线高效组织和管理,提出的方法和标准适用于铁路设计、建设过程的管理和分析应用。 展开更多
关键词 铁路 BIM GIS 智能化 电子沙盘 专题图 高效组织
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准饱和细砂在圈闭气体溶解过程中渗透系数的变化
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作者 程东会 兰盈伯 +6 位作者 袁靖 项琳 杨晓婷 乔晓英 邓林 王梓林 王庆 《水文地质工程地质》 CAS CSCD 北大核心 2024年第6期1-7,共7页
准饱和含水层的渗透系数会随着圈闭气体饱和度的增大而变小,但受限于试验操作和测量精度,通过传统驱替试验很难获得大量连续的圈闭气体饱和度数据,因此限制了小圈闭气体饱和度及其对应的准饱和渗透系数之间关系的准确刻画。研究设计了... 准饱和含水层的渗透系数会随着圈闭气体饱和度的增大而变小,但受限于试验操作和测量精度,通过传统驱替试验很难获得大量连续的圈闭气体饱和度数据,因此限制了小圈闭气体饱和度及其对应的准饱和渗透系数之间关系的准确刻画。研究设计了一个以氧气代替天然圈闭过程中空气的准饱和细砂圈闭气体溶解试验,通过精确测量溶解过程中水中可溶性氧和相应的渗透系数得到了大量连续的圈闭气体饱和度及其准饱和渗透系数的数据。试验结果表明,在小于5%圈闭气体饱和度的区间,圈闭气体进入到无效孔隙中,因此不影响渗透系数的大小;圈闭气体饱和度在5%~6%时会形成孔喉阻塞效应,对渗透系数的影响加剧。在此基础上,构建了预测准饱和渗透系数的van Genuchten模型。与传统Faybishenko幂律模型相比,新构建的模型很好地表征了小圈闭气体饱和度对渗透系数影响不大的特征;在其他圈闭气体饱和度时,新模型与传统模型的预测性能相当。新构建的准饱和渗透系数模型为深入研究准饱和水流和溶质运移奠定了基础。 展开更多
关键词 准饱和细砂介质 圈闭气体饱和度 渗透系数 van Genuchten模型 Faybishenko幂律模型
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旋流沉砂池除砂特性分析及优化
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作者 张睿 江扬阳 +3 位作者 谢锋 李广磊 冯建刚 徐辉 《河海大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第6期53-59,共7页
为研究旋流沉砂池的流动特性,提升其除砂效率,以某污水泵站初步设置的旋流沉砂池为研究对象,基于数值模拟方法,采用RSM模型和DPM模型分析了旋流沉砂池的流动特性和除砂效率,针对其存在的不足提出了增加导流板的结构优化方案,并对不同长... 为研究旋流沉砂池的流动特性,提升其除砂效率,以某污水泵站初步设置的旋流沉砂池为研究对象,基于数值模拟方法,采用RSM模型和DPM模型分析了旋流沉砂池的流动特性和除砂效率,针对其存在的不足提出了增加导流板的结构优化方案,并对不同长度导流板方案进行了对比分析。结果表明:在壁面阻挡和搅拌桨叶片旋转产生的水平环流和立面环流作用下,水流在旋流沉砂池内呈现螺旋形;水流在沿进水渠道进入池体时,对池体内的旋转水流产生冲击,流速较大的进流在压差作用下向池心偏移,容易将靠近池心的砂粒重新卷走,影响旋流沉砂池的除砂效果;在进水渠道末端增设导流板能够有效减小进流对沉砂池内旋转水流的冲击,并使撞击到导流板的水流向下折回到池底,从而提高除砂效率;3种导流板方案中导流板长度为2000 mm的方案除砂效果较优,相较于初始方案,对0.10、0.15、0.20 mm粒径砂粒的除砂效率分别提升了7%、11%、2%。 展开更多
关键词 旋流沉砂池 除砂效率 流动特性 砂粒轨迹 导流板 数值模拟
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雨水调节池沉积物去除效能
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作者 王文亮 张鑫 +4 位作者 赵紫依 李俊奇 蔡然 任自强 李运杰 《给水排水》 CSCD 北大核心 2024年第4期83-87,共5页
雨水调节池是重要的径流污染、径流峰值控制绿色基础设施。雨水调节池设置水质控制容积,颗粒悬浮物通过沉淀作用去除,水质控制容积的设计标准为年径流总量控制率,关键设计参数为设计排空时间与设计表面负荷;通过设置微型池或永久池,可... 雨水调节池是重要的径流污染、径流峰值控制绿色基础设施。雨水调节池设置水质控制容积,颗粒悬浮物通过沉淀作用去除,水质控制容积的设计标准为年径流总量控制率,关键设计参数为设计排空时间与设计表面负荷;通过设置微型池或永久池,可延长雨水停留时间,提升沉积物去除效能。结合案例,系统梳理了雨水调节池沉积物去除效能计算的基本公式,介绍了基于数理统计、SWMM模拟的计算方法,可为完善雨水调节池设计方法提供参考。 展开更多
关键词 雨水调节池 沉积物 绿色基础设施 去除效能
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