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Grain yield and N uptake of maize in response to increased plant density under reduced water and nitrogen supply conditions 被引量:1
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作者 Jingui Wei Qiang Chai +5 位作者 Wen Yin Hong Fan Yao Guo Falong Hu Zhilong Fan QimingWang 《Journal of Integrative Agriculture》 SCIE CSCD 2024年第1期122-140,共19页
The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.H... The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.However,whether an increased maize density can compensate for the negative effects of reduced water and N supply on grain yield and N uptake in the arid irrigated areas remains unknown.This study is part of a long-term positioning trial that started in 2016.A split-split plot field experiment of maize was implemented in the arid irrigated area of northwestern China in 2020 to 2021.The treatments included two irrigation levels:local conventional irrigation reduced by 20%(W1,3,240 m^(3)ha^(-1))and local conventional irrigation(W2,4,050 m^(3)ha^(-1));two N application rates:local conventional N reduced by 25%(N1,270 kg ha^(-1))and local conventional N(360 kg ha^(-1));and three planting densities:local conventional density(D1,75,000 plants ha^(-1)),density increased by 30%(D2,97,500 plants ha-1),and density increased by 60%(D3,120,000 plants ha^(-1)).Our results showed that the grain yield and aboveground N accumulation of maize were lower under the reduced water and N inputs,but increasing the maize density by 30% can compensate for the reductions of grain yield and aboveground N accumulation caused by the reduced water and N supply.When water was reduced while the N application rate remained unchanged,increasing the planting density by 30% enhanced grain yield by 13.9% and aboveground N accumulation by 15.3%.Under reduced water and N inputs,increasing the maize density by 30% enhanced N uptake efficiency and N partial factor productivity,and it also compensated for the N harvest index and N metabolic related enzyme activities.Compared with W2N2D1,the N uptake efficiency and N partial factor productivity increased by 28.6 and 17.6%under W1N1D2.W1N2D2 had 8.4% higher N uptake efficiency and 13.9% higher N partial factor productivity than W2N2D1.W1N2D2 improved urease activity and nitrate reductase activity by 5.4% at the R2(blister)stage and 19.6% at the V6(6th leaf)stage,and increased net income and the benefit:cost ratio by 22.1 and 16.7%,respectively.W1N1D2 and W1N2D2 reduced the nitrate nitrogen and ammoniacal nitrogen contents at the R6 stage in the 40-100 cm soil layer,compared with W2N2D1.In summary,increasing the planting density by 30% can compensate for the loss of grain yield and aboveground N accumulation under reduced water and N inputs.Meanwhile,increasing the maize density by 30% improved grain yield and aboveground N accumulation when water was reduced by 20% while the N application rate remained constant in arid irrigation areas. 展开更多
关键词 water and n reduction plant density MAIZE grain yield n uptake compensation effect
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Combined effects of obstacle and fine water mist on gas explosion characteristics 被引量:5
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作者 Xiaoping Wen Mengming Wang +2 位作者 Fahui Wang Minggao Yu Haoxin Deng 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第12期131-140,共10页
Combined effects of obstacles and fine water mist on a methane-air explosion of a semi-closed pipe were investigated experimentally.In this study,the diameter of the water mist,the location,and the number of obstacles... Combined effects of obstacles and fine water mist on a methane-air explosion of a semi-closed pipe were investigated experimentally.In this study,the diameter of the water mist,the location,and the number of obstacles was considered.The results demonstrated that 5 μm water mist present a significant suppression affected while 45 μm shows a slight promotion effected on a gas explosion of the condition without obstacles.In the presence of an obstacle,however,the inhibitory effect of 5 μm water veils of mist dropped significantly during flame propagation,and the effect of 45 μm water veils of mist changed from the enhancement of inhibition,and its inhibitory effect was significant.The inhibitory effect of 45 μm water veils of mist on gas explosion weakened firstly and then enhanced with the increasing distance between obstacle location from the ignition location as well as in several obstacles. 展开更多
关键词 Fine water mist Gas explosion suppression OBSTACLE Couple effects
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Coupling Effect of Water and Fertilizer on Soybean Yield and Nutrient Absorption 被引量:2
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作者 HAO Li ZU Wei +2 位作者 SUN Cong-shu LEI Shu-xia LIU Li-jun 《Journal of Northeast Agricultural University(English Edition)》 CAS 2003年第2期105-114,共10页
Soybean cultivar Bei 92-28 was tested in this experiment in 2000 to study the coupling effect of water and ferilizer on soybean yield.The results showed that the effect of irrigation varied among the levels of fertili... Soybean cultivar Bei 92-28 was tested in this experiment in 2000 to study the coupling effect of water and ferilizer on soybean yield.The results showed that the effect of irrigation varied among the levels of fertilizer application,and vice versa;pods per plant,seeds per pod.and 100-seed weight had positive correlations with soybean yield,but the degrees of correlations of different treatments were various;LAI and dry matter accumulation could be significantly increased when watered and applied fertilizer with different levels,but high fertilizer application treatment didn't obtain the highest yield;watering could increase the absolute absorption amount of N,P,K in seeds,but the accumulation rates were various. 展开更多
关键词 coupling effect water FERTILIZER soybean yield
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陆地高分辨率水文—生物地球化学过程CNMM-DNDC三维模型的研发及应用进展
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作者 郑循华 李思琪 +7 位作者 张伟 刘春岩 姚志生 韩圣慧 王睿 王凯 陈笑 李勇 《大气科学》 CSCD 北大核心 2024年第1期92-107,共16页
CNMM-DNDC模型是本文作者团队研发的陆地高分辨率水文—生物地球化学过程三维模型。本文系统介绍了建模背景和理念、核心过程和模型特点、模拟功能和观测验证、多尺度区域或流域初步应用以及未来发展展望。自2018年刊发首个版本以来,该... CNMM-DNDC模型是本文作者团队研发的陆地高分辨率水文—生物地球化学过程三维模型。本文系统介绍了建模背景和理念、核心过程和模型特点、模拟功能和观测验证、多尺度区域或流域初步应用以及未来发展展望。自2018年刊发首个版本以来,该模型经过了多方面科学过程改进和模拟功能扩展,在元素化学反应、物质相变和机械迁移等基本物理、化学、生物过程层面,完成了对陆地表层系统碳氮磷水循环全耦合的精细刻画。迄今开展的观测验证表明,CNMM-DNDC模型基本普适于不同生物气候带(从热带到寒区多年冻土地带)的流域或区域长时间序列“三高”(时间、空间和过程高分辨率)综合模拟,实现对陆地生态系统的碳、氮、磷、水三维运移、水土流失、水力驱动溶解态和颗粒态碳氮磷横向迁移、碳氮温室气体和污染气体排放、生态系统生产力、水分蒸散发和水分能量平衡等众多可持续发展目标表征变量的预测。该模型广泛推广应用于多尺度区域或流域的复杂过程虚拟科学试验研究和服务于面向生态环境建设与减污降碳的优化调控决策,可望为协同落实联合国多个可持续发展目标提供先进的数值模拟技术支撑。 展开更多
关键词 碳氮磷水循环全耦合模拟 水文—生物地球化学过程模型 CnMM-DnDC模型 联合国可持续发展目标
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A review of nanocarbons in energy electrocatalysis: Multifunctional substrates and highly active sites 被引量:15
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作者 Cheng Tang Maria-Magdalena Titirici Qiang Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2017年第6期1077-1093,共17页
Nanocarbons are of progressively increasing importance in energy electrocatalysis, including oxygen reduction, oxygen evolution, hydrogen evolution, COreduction, etc. Precious-metal-free or metal-free nanocarbon-based... Nanocarbons are of progressively increasing importance in energy electrocatalysis, including oxygen reduction, oxygen evolution, hydrogen evolution, COreduction, etc. Precious-metal-free or metal-free nanocarbon-based electrocatalysts have been revealed to potentially have effective activity and remarkable durability, which is promising to replace precious metals in some important energy technologies,such as fuel cells, metal–air batteries, and water splitting. In this review, rather than overviewing recent progress completely, we aim to give an in-depth digestion of present achievements, focusing on the different roles of nanocarbons and material design principles. The multifunctionalities of nanocarbon substrates(accelerating the electron and mass transport, regulating the incorporation of active components,manipulating electron structures, generating confinement effects, assembly into 3 D free-standing electrodes) and the intrinsic activity of nanocarbon catalysts(multi-heteroatom doping, hierarchical structure,topological defects) are discussed systematically, with perspectives on the further research in this rising research field. This review is inspiring for more insights and methodical research in mechanism understanding, material design, and device optimization, leading to a targeted and high-efficiency development of energy electrocatalysis. 展开更多
关键词 nAnOCARBOn Energy electrocatalysis Oxygen reduction Oxygen evolution Hydrogen evolution CO_2 reduction Electron structure Strong coupling effect Hierarchical structure DOPInG Defect Metal–air battery Fuel cell water splitting
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Coupled hydro-mechanical effect of a fractured rock mass under high water pressure 被引量:2
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作者 Zhongming Jiang Shurong Feng Sheng Fu 《Journal of Rock Mechanics and Geotechnical Engineering》 2012年第1期88-96,共9页
To explore the variation of permeability and deformation behaviors of a fractured rock mass in high water pressure,a high pressure permeability test(HPPT),including measuring sensors of pore water pressure and displ... To explore the variation of permeability and deformation behaviors of a fractured rock mass in high water pressure,a high pressure permeability test(HPPT),including measuring sensors of pore water pressure and displacement of the rock mass,was designed according to the hydrogeological condition of Heimifeng pumped storage power station.With the assumption of radial water flow pattern in the rock mass during the HPPT,a theoretical formula was presented to estimate the coefficient of permeability of the rock mass using water pressures in injection and measuring boreholes.The variation in permeability of the rock mass with the injected water pressure was studied according to the suggested formula.By fitting the relationship between the coefficient of permeability and the injected water pressure,a mathematical expression was obtained and used in the numerical simulations.For a better understanding of the relationship between the pore water pressure and the displacement of the rock mass,a 3D numerical method based on a coupled hydro-mechanical theory was employed to simulate the response of the rock mass during the test.By comparison of the calculated and measured data of pore water pressure and displacement,the deformation behaviors of the rock mass were analyzed.It is shown that the variation of displacement in the fractured rock mass is caused by water flow passing through it under high water pressure,and the rock deformation during the test could be calculated by using the coupled hydro-mechanical model. 展开更多
关键词 fractured rock mass permeability under the condition of high water head hydro-mechanical coupling effect
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Experimental Investigation on Vortex-Induced Vibration of Deep-Sea Risers of Different Excitation Water Depths
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作者 LI Peng DONG Zheng-kai +4 位作者 LIU Yu WANG Yu CONG Ai-jun GUO Haiyan FU Qiang 《China Ocean Engineering》 SCIE EI CSCD 2021年第2期215-227,共13页
The vortex-induced vibration test of the deep-sea riser was carried out with different excitation water depths in the wave-current combined water flume.By dimensionally changing the multi-stage water depth and hydrody... The vortex-induced vibration test of the deep-sea riser was carried out with different excitation water depths in the wave-current combined water flume.By dimensionally changing the multi-stage water depth and hydrodynamic parameters such as outflow velocity at various water depths,the dynamic response parameters such as dominant frequency,dimensionless displacement and vibration trajectory evolution process of the riser under different excitation water depths were explored to reveal the sensitive characteristics of the dynamic response of vortexinduced vibration of the risers under different excitation water depths.The results show that different excitation water depths will change the additional mass of the riser and the fluid damping and other parameters,which will affect the spatial correlation and stability of the vortex shedding behind the riser.In the lock-in region,the distribution range of the characteristic frequency becomes narrow and centered on the lock-in frequency.The increase of the excitation water depth gradually advances the starting point of the lock-in region of the riser,and at the same time promotes the excitation of the higher-order vibration frequency of the riser structure.Within the dimensionless excitation water depth,the dominant frequency and dimensionless displacement are highly insensitive to the excitation water depth at high flow velocity.The change of the excitation water depth will interfere with the correlation of the non-linear coupling of the riser.The“8-shaped”gradually becomes irregular,and the vibration trajectories of the riser show“O-shape”,“X-shape”and“Crescent-shape”. 展开更多
关键词 deep-sea riser excitation water depth vortex-induced vibration(VIV) dynamic response coupling effect
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养殖水体NO_(2)^(-)-N降解复合菌剂制备及特性研究
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作者 伍俊溢 魏祥东 《现代畜牧科技》 2024年第6期20-24,共5页
随着我国水产养殖规模也逐年上升,养殖水体中氮化合物累积问题日益严重。为实现我国水产行业的安全生产,本文筛选出一种NO_(2)^(-)-N降解菌,并与光合菌、乳酸菌进行复配以此制备复合菌剂。通过单因素试验分析温度、pH值、亚硝酸盐初始... 随着我国水产养殖规模也逐年上升,养殖水体中氮化合物累积问题日益严重。为实现我国水产行业的安全生产,本文筛选出一种NO_(2)^(-)-N降解菌,并与光合菌、乳酸菌进行复配以此制备复合菌剂。通过单因素试验分析温度、pH值、亚硝酸盐初始浓度、菌种接种量等对NO_(2)^(-)-N降解的影响,确定不同影响因素下复合菌剂的最佳降解效果和生长状态。研究结果表明,从活性淤泥中筛选带1株具有高效NO_(2)^(-)-N氧化性质的菌株A3,并与光合细菌(Rhodopseudomonas palustris)、乳酸菌(Lactobacillus acidophilus)按照32∶2∶1混合,该比例降解效率最高。复合菌剂在40℃,pH值为9.0、pH值为6.0的条件下,OD600值稳定在0.2~0.4,对NO_(2)^(-)-N的降解率保持在50%左右。复合菌剂在25℃,pH值为7.5的条件下长势最好,降解率最高;复合菌剂的降解率随初始NO_(2)^(-)-N浓度的升高而降低,OD600值变化不明显,表明复合菌剂与A3菌株对NO_(2)^(-)-N有很强的耐受性,能够在0.1~8.0 g/L的条件下维持降解活性,保持一定的降解速率。 展开更多
关键词 复合微生物菌剂 nO_(2)^(-)-n 养殖水体 nO_(2)^(-)-n高效氧化菌
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The effects of process conditions on the plasma characteristic in radio-frequency capacitively coupled SiH_4/NH_3/N_2 plasmas: Two-dimensional simulations
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作者 刘相梅 宋远红 +1 位作者 姜巍 易林 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第4期338-343,共6页
A two-dimensional (2D) fluid model is presented to study the behavior of silicon plasma mixed with SiH4 , N2 , and NH3 in a radio-frequency capacitively coupled plasma (CCP) reactor. The plasma–wall interaction ... A two-dimensional (2D) fluid model is presented to study the behavior of silicon plasma mixed with SiH4 , N2 , and NH3 in a radio-frequency capacitively coupled plasma (CCP) reactor. The plasma–wall interaction (including the deposition) is modeled by using surface reaction coefficients. In the present paper we try to identify, by numerical simulations, the effect of variations of the process parameters on the plasma properties. It is found from our simulations that by increasing the gas pressure and the discharge gap, the electron density profile shape changes continuously from an edge-high to a center-high, thus the thin films become more uniform. Moreover, as the N2 /NH3 ratio increases from 6/13 to 10/9, the hydrogen content can be significantly decreased, without decreasing the electron density significantly. 展开更多
关键词 capacitively coupled plasma process conditions effects SiH4/nH3/n2 discharges
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Tidal effects on temperature iront in the Yellow Sea 被引量:6
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作者 马建 乔方利 +1 位作者 夏长水 杨永增 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2004年第3期314-321,共8页
Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring,thrives in summer, and fades in autumn as thermocline declines. TF intensity |ST| is defined to describe the distributio... Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring,thrives in summer, and fades in autumn as thermocline declines. TF intensity |ST| is defined to describe the distribution of TF. Based on the MASNUM wave-tide-circulation coupled model, temperature distribution in the Yellow Sea was simulated with and without tidal effects. Along 36°N, distribution of TF from the simulated results are compared with the observations, and a quantitative analysis is introduced to evaluate the tidal effects on the forming and maintaining processes of the TF. Tidal mixing and the circulation structure adapting to it are the main causes of the TF. 展开更多
关键词 数字模型 波浪 潮汐 环流 黄海
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Analysis Methods for the Determination of Anthropogenic Additions of P to Agricultural Soils
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作者 Richard L. Haney Virginia L. Jin +4 位作者 Mari-Vaughn V. Johnson Elizabeth B. Haney R. Daren Harmel Jeffrey G. Arnold Michael J. White 《Open Journal of Soil Science》 2015年第2期59-68,共10页
Phosphorus loading and measurement is of concern on lands where biosolids have been applied. Traditional soil testing for plant-available P may be inadequate for the accurate assessment of P loadings in a regulatory e... Phosphorus loading and measurement is of concern on lands where biosolids have been applied. Traditional soil testing for plant-available P may be inadequate for the accurate assessment of P loadings in a regulatory environment as the reported levels may not correlate well with environmental risk. In order to accurately assess potential P runoff and leaching, as well as plant uptake, we must be able to measure organic P mineralized by the biotic community in the soil. Soils with varying rates of biosolid application were evaluated for mineralized organic P during a 112-day incubation using the difference between P measured using a rapid-flow analyzer (RFA) and an axial flow Varian ICP-OES. An increase in the P mineralized from the treated soils was observed from analysis with the Varian ICP-OES, but not with the RFA. These results confirm that even though organic P concentrations have increased due to increasing biosolid application, traditional soil testing using an RFA for detection, would not accurately portray P concentration and potential P loading from treated soils. 展开更多
关键词 Phosphorus AnTHROPOGEnIC ADDITIOnS Biosolids Rapid-Flow Analyzer (RFA) Inductively Coupled Plasma (ICP) Texas Commission of Environmental Quality (TCEQ) Soil ORGAnIC C (SOC) Total n (Tn) water-Soluble ORGAnIC C (WSOC) water Soluble ORGAnIC n (WSOn)
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多面体SrTiO_(3)原位生长N缺陷PCN中的纳米叠层效应助力光催化完全分解水:内建电场调控的协同机制
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作者 韦之栋 严嘉玮 +1 位作者 郭伟琦 上官文峰 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2023年第5期279-289,共11页
光的钻穿效应使得纳米级光催化剂(粒径200nm以下催化剂和低维催化剂等)能带弯曲程度降低,无法有效利用“向阳背阴”的Dember效应,进而削弱光生载流子从体相到表面的驱动力,不利于完全分解水的实现.我们前期研究发现,催化剂微结构的极化... 光的钻穿效应使得纳米级光催化剂(粒径200nm以下催化剂和低维催化剂等)能带弯曲程度降低,无法有效利用“向阳背阴”的Dember效应,进而削弱光生载流子从体相到表面的驱动力,不利于完全分解水的实现.我们前期研究发现,催化剂微结构的极化率影响其扭曲度,进而可以实现对催化剂内建电场的调控,促进纳米颗粒光催化完全分解水的过程.基于此,本文在粒径小于200 nm的多面体SrTiO_(3)催化剂表面.原位生长聚合物的氮化碳(PCN),形成了薄层PCN包覆的SrTiO_(3)纳米叠层催化剂,实现了完全分解水过程.并利用物相结构分析、形貌分析、表面分析、光谱分析、同步辐射分析和理论计算等方法深入解析了SrTiO_(3)-PCN复合催化剂的结构,揭示了由纳米尺度的叠层效应引发的内建电场协同调控机制.催化剂的物相结构分析结果表明,SrTiO_(3)和PCN是组成复合催化剂的主要单体,并没有新的物质生成,复合后各元素微结构极化率发生变化,表现为拉曼光谱峰强度的变化.片层状的PCN包覆在多面体SrTiO_(3)的表面,形成了独特的复合催化剂叠层结构.N 1s与Sr 3d的X射线光电子能谱结果表明,SrTiO_(3)与PCN的结合围绕着Sr和N两种元素进行.随着SrTiO_(3)含量的增加,-NH_(2)中的N与SrTiO_(3)中的元素结合,促进了-N-H基团的生成,而-N-H-基团受到化学环境改变的影响,倾向于向氰基转变,进而形成缺陷.利用同步辐射研究了Sr原子配位数的变化,揭示了N-Sr键的形成源自于Sr-Ti键中的Sr与-NH_(2)中的N结合,促进了N缺陷态的形成,显著提升了光吸收性能.催化剂热力学分析结果表明,体相氮缺陷引起价带位置上移,而表面氮缺陷对价带位置影响较小.当SrTiO_(3)/PCN的比为1:2时,复合催化剂可以实现完全分解水过程,氢氧比接近2:1.其原因在于SrTiO_(3)与PCN之间的费米能级不同,N-Sr键的形成增强了表面电势,促进了二者复合后内建电场的重构.随着SrTiO_(3)含量的增加,体相缺陷浓度增加,进而使得分解水性能显著降低.研究表明,由N-Sr形成使得催化剂在光吸收率、热力学性质及动力学性质的改变所引起的纳米尺度叠层效应,是引发内建电场协同调控进而实现光催化完全分解水的重要因素.综上,本文结果可以对调控内建电场实现完全分解水方面研究提供一定借鉴. 展开更多
关键词 光催化水分解 纳米叠层效应 内建电场 氮缺陷的聚合物氮化碳 纳米多面体钛酸锶
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1958—2017年江西省水稻需水量与有效降雨量耦合关系分析
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作者 李娜 袁成福 +3 位作者 罗凤春 胡龙颂 周昌明 王艳艳 《水资源与水工程学报》 CSCD 北大核心 2024年第1期206-216,共11页
基于江西省15个气象站点1958—2017年逐日气象数据,利用Penman-Monteith方法、Mann-Kendall趋势检验、气候倾向率和ArGIS空间插值分析等方法,分析了早稻和晚稻生育期内有效降雨量(P_(e))、需水量(ET_(c))及需水量与有效降雨量耦合度(λ... 基于江西省15个气象站点1958—2017年逐日气象数据,利用Penman-Monteith方法、Mann-Kendall趋势检验、气候倾向率和ArGIS空间插值分析等方法,分析了早稻和晚稻生育期内有效降雨量(P_(e))、需水量(ET_(c))及需水量与有效降雨量耦合度(λ)时空分布特征。结果表明:江西省早稻和晚稻生育期内平均有效降雨量分别为186.69和119.26 mm,早稻和晚稻有效降雨量分别以1.00和1.31 mm/10a的平均速度增加,赣北有效降雨量及其上升趋势均大于赣南;早稻和晚稻生育期多年平均需水量分别为335.77和381.20 mm,早稻和晚稻需水量最大值均出现在赣州、吉安站附近区域,最小值均出现在庐山、修水站附近区域,早稻需水量和晚稻需水量变化趋势分别为-3.09和-7.95 mm/10a;早稻和晚稻需水量与有效降雨量耦合度多年平均值分别为0.57和0.33,早稻和晚稻耦合度均以0.01/10a呈不显著增加趋势。早稻和晚稻耦合度最大值均出现在庐山站,早稻和晚稻耦合度较小值均在赣州、吉安、南昌和波阳站,总体上,早、晚稻耦合度及耦合度倾向率均为赣北大于赣南,赣南地区水稻缺水情况比赣北更严重,尤其要关注赣南地区晚稻缺水情况,并做好水资源规划及制定灌溉措施。 展开更多
关键词 有效降雨量 需水量 耦合度 时空分布 水稻 江西省
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渭北旱塬矮化富士苹果幼树N,K营养状况分析 被引量:10
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作者 王进鑫 张晓鹏 +1 位作者 高保山 王健 《西北农林科技大学学报(自然科学版)》 CSCD 北大核心 2004年第10期20-24,共5页
 采用311-A最优混合设计,以有机肥、无机肥(mN∶mP2O5∶mK2O=1∶0.7∶1)和补充灌水量为主要因子,通过田间试验和室内叶分析,对无病毒矮化红富士苹果树体的N,K营养状况进行了研究。结果表明,在渭北旱塬南缘,红富士苹果幼园不施肥或施肥...  采用311-A最优混合设计,以有机肥、无机肥(mN∶mP2O5∶mK2O=1∶0.7∶1)和补充灌水量为主要因子,通过田间试验和室内叶分析,对无病毒矮化红富士苹果树体的N,K营养状况进行了研究。结果表明,在渭北旱塬南缘,红富士苹果幼园不施肥或施肥不足,均会造成树体N,K营养缺乏,成为影响幼树生长发育的主要限制因子,其中以N素缺乏尤为严重;在中量施肥条件下,N,K营养均为非限制性因素,但补充灌水能提高养分的有效性。对树体生长、发育和营养状况进行综合分析后确定,渭北旱塬南缘矮化红富士幼树的最适施肥量、灌水量分别为:有机肥20000~24536kg/hm2,无机肥N,K2O均为376.90~501.2kg/hm2,P2O5263.80~350.84kg/hm2,平水年补充灌水量为24.8~61.8mm,丰水年可不进行补充灌水。 展开更多
关键词 渭北旱塬 矮化栽培 富士苹果 幼树 n K 营养状况
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棉花不同水氮组合NDVI的差异性及产量效应研究 被引量:2
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作者 温鹏飞 朱鹏 +4 位作者 吕新 张泽 张强 陶垿 王飞 《灌溉排水学报》 CSCD 北大核心 2016年第10期69-72,共4页
为建立最优水氮组合提供参考,设置4个氮肥处理、3个水分处理的大田试验,随机分组,分析了棉花不同水氮组合NDVI和棉花生长状况的差异性,建立以产量为因变量的水肥模型。结果表明,不同水氮组合的棉花冠层NDVI变化都呈"低-高-低"... 为建立最优水氮组合提供参考,设置4个氮肥处理、3个水分处理的大田试验,随机分组,分析了棉花不同水氮组合NDVI和棉花生长状况的差异性,建立以产量为因变量的水肥模型。结果表明,不同水氮组合的棉花冠层NDVI变化都呈"低-高-低"趋势。施氮量对棉花冠层NDVI的影响大于灌水;依据建立水氮效应的产量模型确定的最高施氮量和灌水量分别为298.47 kg/hm2和3 698.75 m3/hm2,理论棉花产量为6 597.02 kg/hm2。因此,合理的水氮组合既能减少水肥浪费,又能提高棉花产量。棉花冠层NDVI能够很好地反映棉花生长状况,可替代传统方法获取棉花生长指标。 展开更多
关键词 水肥耦合 GreenSeeker 棉花 产量
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含NaCl荷电细水雾对甲烷爆炸火焰传播的抑制特性 被引量:16
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作者 余明高 吴丽洁 +1 位作者 万少杰 郑凯 《化工学报》 EI CAS CSCD 北大核心 2017年第11期4445-4452,共8页
为进一步提高细水雾抑制甲烷爆炸的效率,搭建了小尺寸细水雾抑制甲烷爆炸实验平台,在普通细水雾中添加NaCl添加剂,并对其荷电,进行含NaCl添加剂荷电细水雾抑制甲烷爆炸火焰传播特性的实验研究。结果表明,含NaCl添加剂荷电细水雾对甲烷... 为进一步提高细水雾抑制甲烷爆炸的效率,搭建了小尺寸细水雾抑制甲烷爆炸实验平台,在普通细水雾中添加NaCl添加剂,并对其荷电,进行含NaCl添加剂荷电细水雾抑制甲烷爆炸火焰传播特性的实验研究。结果表明,含NaCl添加剂荷电细水雾对甲烷爆炸火焰传播的抑制效果,优于普通细水雾单独添加NaCl添加剂和荷电作用的抑制效果之和。随着NaCl浓度和荷电电压的增大,甲烷爆炸火焰传播速度明显减小;其中荷电8 kV、NaCl浓度12.5%的工况抑制效果最佳,甲烷爆炸火焰传播速度二次峰值较普通细水雾作用时下降了10.747 m·s^(-1),下降比例高达60.26%;分析认为,在细水雾抑制甲烷爆炸火焰传播的过程中,NaCl添加剂和荷电作用之间存在相互促进抑制效果的耦合作用。 展开更多
关键词 感应荷电 naCl添加剂 细水雾 甲烷 火焰速度 耦合作用
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玉米秸秆及其黑炭添加对黄绵土CO_2和N_2O排放的影响 被引量:9
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作者 刘娇 袁瑞娜 +1 位作者 赵英 张阿凤 《农业环境科学学报》 CAS CSCD 北大核心 2014年第8期1659-1668,共10页
采用二次通用旋转组合设计,在室内进行恒温(28℃)培养试验,探讨在室内培养条件下土壤水分、有机碳(秸秆、黑炭)和氮素耦合对温室气体(CO2和N2O)排放的影响,并建立回归模型对试验数据进行回归分析,结果表明:(1)相比施加秸秆来说,在土壤... 采用二次通用旋转组合设计,在室内进行恒温(28℃)培养试验,探讨在室内培养条件下土壤水分、有机碳(秸秆、黑炭)和氮素耦合对温室气体(CO2和N2O)排放的影响,并建立回归模型对试验数据进行回归分析,结果表明:(1)相比施加秸秆来说,在土壤中施加黑炭具有显著的减排效果。(2)以秸秆作为碳源时,水、碳、氮三因子对土壤两种温室气体(CO2和N2O)累积排放量的影响大小均表现为有机碳>水分>氮素;以黑炭作为碳源时,水碳氮三因子对土壤CO2累积排放量的影响大小表现为水分>有机碳>氮素,对土壤N2O累积排放量的影响为有机碳>氮素>水分。(3)水碳氮交互作用对土壤CO2累积排放量的影响表现为:施加秸秆时为碳氮>水氮>水碳,施加黑炭时为水碳=水氮>碳氮;而对N2O累积排放量的影响而言,施加秸秆时为水碳>碳氮>水氮,施加黑炭时为水氮>碳氮>水碳。(4)研究认为,令CO2累积排放量最小的水碳氮组合以秸秆作为碳源时为水分含量30%、不施加秸秆和氮素施加量81.9 mg kg-1,以黑炭作为碳源时为水分含量10%、不施加黑炭和氮素施加量48.4 mg·kg-1;令N2O累积排放量最小的水碳氮组合以秸秆作为碳源时为水分含量30%、不施加秸秆和氮素施加量100 mg·kg-1,以黑炭作为碳源时为水分含量10%、不施加黑炭和氮素施加量100mg·kg-1。 展开更多
关键词 黄绵土 水碳氮耦合 秸秆 黑炭 温室气体
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南水北调中线工程输水建筑物整流累积效应研究
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作者 陈晓楠 白一墨 +4 位作者 胡羽蝶 曾诚 夏悦玥 尹雨然 王玲玲 《水利水电科技进展》 CSCD 北大核心 2024年第2期61-65,98,共6页
为分析输水建筑物整流对南水北调中线工程输水能力的影响,以陶岔渠首闸至十二里河渡槽渠段为例,建立一二维耦合水动力模型,其中渠道段采用一维模型,4个输水建筑物段(刁河渡槽、湍河渡槽、严陵河渡槽和淇河倒虹吸)采用二维模型,利用多年... 为分析输水建筑物整流对南水北调中线工程输水能力的影响,以陶岔渠首闸至十二里河渡槽渠段为例,建立一二维耦合水动力模型,其中渠道段采用一维模型,4个输水建筑物段(刁河渡槽、湍河渡槽、严陵河渡槽和淇河倒虹吸)采用二维模型,利用多年实测数据对耦合模型进行率定。分别对无整流方案和15种整流方案进行模拟计算,分析不同整流方案对上下游的影响,进而确定水头损失最小的整流方案。结果表明:单体整流影响范围为建筑物上下游3~5 km,多个建筑物整流的累积效果小于单个建筑物整流效果的线性叠加;对渠段中间2个输水建筑物(湍河渡槽、严陵河渡槽)进行整流的效果优于对上下游2个输水建筑物(刁河渡槽、淇河倒虹吸)进行整流的效果。 展开更多
关键词 输水建筑物 整流 累积效应 数值模拟 一二维耦合模型 南水北调中线工程
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水肥耦合效应对设施番茄生长及水分利用效率的影响
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作者 祝洋 刘志应 +2 位作者 李新苗 王楠 张娟 《山东农业科学》 北大核心 2024年第4期92-101,共10页
为提高南疆地区设施栽培番茄的水分利用效率和高效栽培,并提高新疆产蛭石的利用率,将蛭石与黄沙、菇渣混合,研究以蛭石为主复合基质栽培模式下温室番茄生长的水肥耦合效应。试验以“双赢先锋”番茄为材料,设灌水量、氮、磷、钾4个因子... 为提高南疆地区设施栽培番茄的水分利用效率和高效栽培,并提高新疆产蛭石的利用率,将蛭石与黄沙、菇渣混合,研究以蛭石为主复合基质栽培模式下温室番茄生长的水肥耦合效应。试验以“双赢先锋”番茄为材料,设灌水量、氮、磷、钾4个因子素采用四因素五水平二次正交旋转组合设计的二分之一执行,设置18组水肥耦合处理,其中5组灌水量分别设置为基质田间持水率的66.0%、70.8%、78.0%、85.2%、90.0%,分析各因子的主效应、单因素效应和双因素耦合效应。结果表明:①经综合评价,W18为最优处理,即在灌水量为78.0%的田间持水率下,施N 340 kg/hm^(2)、P_(2)O_(5)185 kg/hm^(2)、K_(2)O 310 kg/hm^(2),番茄的生长和水分利用效率为最优水平,有利于提升产量。灌水量对水分利用效率起决定作用,灌水量与施氮量具有耦合正效应,同一灌水量下,适当提高氮肥用量有利于番茄对水分的利用,但过量施氮则不利于水分利用效率的提高。②灌水量、施氮量、施磷量对番茄生长有显著正效应,而施钾量对番茄的生长作用不显著,各因素对番茄生长的主效应大小为灌水量>施氮量>施磷量>施钾量。③单因素效应分析表明:各生长指标随着水肥的增加先上升后下降,呈抛物线趋势,水肥过高或过低都会使番茄生长受到抑制。④耦合效应分析表明:水氮耦合、水磷耦合、氮磷耦合对番茄生长有耦合正效应,均能显著促进番茄生长,其中水氮耦合的作用最大。 展开更多
关键词 设施番茄 水肥耦合效应 生长 水分利用效率
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基于去离子水冷却±800 kV换流变压器阀侧套管的冷却效果和参数的影响
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作者 刘杉 高冲 +2 位作者 侯俊义 周建辉 卢斌先 《电工技术学报》 EI CSCD 北大核心 2024年第12期3884-3894,共11页
随着我国±800 kV大容量特高压直流输电的快速发展,环氧树脂套管的过热问题备受关注。基于去离子水冷却,该文将环氧树脂套管的水道结构由多管道式改进为一体化结构。采用三维电-热-流场耦合分析方法,考虑热传导和热对流的影响,模拟... 随着我国±800 kV大容量特高压直流输电的快速发展,环氧树脂套管的过热问题备受关注。基于去离子水冷却,该文将环氧树脂套管的水道结构由多管道式改进为一体化结构。采用三维电-热-流场耦合分析方法,考虑热传导和热对流的影响,模拟了换流变压器阀侧套管的温度场分布。通过与温升实验数据对比,仿真结果与实验结果的误差在3.99%以内,验证了该套管模型设计的合理性。与去离子水冷却的多管道式套管相比,改进后的±800 kV去离子水冷却一体化套管的载流导体外表面的最高温度更低且环氧树脂内表面的温差更小,结果表明该套管的去离子水冷却效果极强。研究了水道尺寸、流量和入口水温对去离子水冷却一体化套管温度分布的影响,结果表明该套管的温度分布主要由入口水温和流量控制,将去离子水的流量设置为10 L/min时几乎可以带走套管产生的全部热量,且入口水温越低冷却效果越好。分析结果可用于去离子水冷却±800 kV环氧树脂套管的结构优化与设计。 展开更多
关键词 去离子水 电-热-流场耦合模型 冷却效果 参数扫描 高压套管
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