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Modeling grassland net primary productivity and water-use efficiency along an elevational gradient of the Northern Tianshan Mountains 被引量:5
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作者 QiFei HAN GePing LUO +2 位作者 ChaoFan LI Hui YE YaoLiang CHEN 《Journal of Arid Land》 SCIE CSCD 2013年第3期354-365,共12页
Mountainous ecosystems are considered highly sensitive and vulnerable to natural disasters and cli- rnatic changes. Therefore, quantifying the effects of elevation on grassland productivity to understand ecosys- tem-c... Mountainous ecosystems are considered highly sensitive and vulnerable to natural disasters and cli- rnatic changes. Therefore, quantifying the effects of elevation on grassland productivity to understand ecosys- tem-climate interactions is vital for mountainous ecosystems. Water-use efficiency (WUE) provides a useful index for understanding the metabolism of terrestrial ecosystems as well as for evaluating the degradation of grasslands. This paper explored net primary productivity (NPP) and WUE in grasslands along an elevational gradient ranging from 400 to 3,400 m asl in the northern Tianshan Mountains-southern Junggar Basin (TMJB), Xinjiang of China, using the Biome-BGC model. The results showed that: 1 ) the NPP increased by 0.05 g C/(m2-a) with every increase of 1-m elevation, reached the maximum at the mid-high elevation (1,600 m asl), and then decreased by 0.06 g C/(m2.a) per 1-m increase in elevation; 2) the grassland NPP was positively correlated with temperature in alpine meadow (AM, 2,700-3,500 m asl), mid-mountain forest meadow (MMFM, 1,650-2,700 m asl) and low-mountain dry grassland (LMDG, 650-1,650 m asl), while positive correlations were found between NPP and annual precipitation in plain desert grassland (PDG, lower than 650 m asl); 3) an increase (from 0.08 to 1.09 g C/(m2.a)) in mean NPP for the grassland in TMJB under a real climate change scenario was observed from 1959 to 2009; and 4) remarkable differences in WUE were found among different elevations, in general, WUE increased with decreasing elevation, because water availability is lower at lower elevations; however, at elevations lower than 540 m asl, we did observe a decreasing trend of WUE with decreasing elevation, which may be due to the sharp changes in canopy cover over this gradient. Our research suggests that the NPP simulated by Biome-BGC is consistent with field data, and the modeling provides an opportunity to further evaluate interactions between environmental factors and ecosystem productivity. 展开更多
关键词 elevational gradient net primary production water-use efficiency CLIMATE
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Effect of slope gradient on the subsurface water flow velocity of sand layer profile 被引量:3
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作者 HAN Zhen CHEN Xiao-yan +3 位作者 HUANG Yu-han LUO Bang-lin XING Hang HUANG Yong-chao 《Journal of Mountain Science》 SCIE CSCD 2020年第3期641-652,共12页
Subsurface water flow velocity influences the hydrodynamic characteristics of soil seepage and the interaction between subsurface water flow and surface runoff during soil erosion and sediment transport.A visualized m... Subsurface water flow velocity influences the hydrodynamic characteristics of soil seepage and the interaction between subsurface water flow and surface runoff during soil erosion and sediment transport.A visualized method and equipment was adopted in this study to observe the subsurface water flow.Quartz sand was used as the test material of subsurface water flow and fluorescent dye was used as the indicator for tracing subsurface water flow.Water was supplied at the same flow discharge to the three parts at the bottom of the test flume,and the subsurface water flow were determined with four slope gradients(4°,8°,10°,and 12°).The results showed that the seepage velocity gradually increased with increasing slope gradient.The pore water velocity at different depths of sand layer profile increased with increasing slope gradient,whereas the thickness of the flow front gradually decreased.For the same slope gradient,the pore water velocity in the lower layer was the largest,whereas the thickness of the flow front was the smallest.Comparative analysis of the relationship between seepage velocity and pore water velocity at different depths of sand layer profile showed that the maximum relative difference between the measured pore water velocity and the computational pore water velocity at different depths of sand profile in the experiment was 4.38%.Thus,the test method for measuring the subsurface water flow velocity of sand layer profile adopted in this study was effective and feasible.The development of this experiment and the exploration of research methods would lay a good test foundation for future studies on the variation law of subsurface water flow velocity and the determination of flow velocity in purple soils,thus contributing to the improvement of the hydrodynamic mechanism of purple soils. 展开更多
关键词 SUBSURFACE water flow PORE water VELOCITY SEEPAGE VELOCITY SLOPE gradient Sand layer
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Separation of Fe<sub>3</sub>O<sub>4</sub>Nanoparticles from Water by Sedimentation in a Gradient Magnetic Field
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作者 I. Medvedeva Iu. Bakhteeva +6 位作者 S. Zhakov A. Revvo M. Uimin A. Yermakov I. Byzov A. Mysik N. Shchegoleva 《Journal of Water Resource and Protection》 2015年第2期111-118,共8页
Sedimentation dynamics of magnetite (γ-Fe3O4) nanopowders (10 - 20 nm) in water in the presence of a gradient magnetic field was studied by optical and Nuclear Magnetic Resonance (NMR) relaxometry methods. The magnet... Sedimentation dynamics of magnetite (γ-Fe3O4) nanopowders (10 - 20 nm) in water in the presence of a gradient magnetic field was studied by optical and Nuclear Magnetic Resonance (NMR) relaxometry methods. The magnetic field B ≤ 0.3 T, dB/dz ≤ 0.13 T/cm was produced by the system of permanent strip magnets. The initial sedimentation rate of the nanoparticles in water and under magnetic fields is higher for less concentrated suspensions (c0 = 0.1 g/l) than for more concentrated ones (c0 = 1 g/l). This might be connected with the formation of gel structures due to strong magnetic attraction between ferromagnetic nanoparticles. In the gravitation field, the suspensions of the particles (10 - 20 nm) remain stable for over 20 hours. The sedimentation process can be greatly accelerated by the action of a vertical gradient magnetic field, reducing the sedimentation time down to several minutes. In a gradient magnetic field enhanced by a steel grid, sedimentation of the nanopowder (c0 = 0.1 g/l) for 180 minutes resulted in reduction of the iron concentration in water down to 0.4 mg/l. In flowing water regime, the residual iron concentration in water 0.3 mg/l is reached after 80 minutes. 展开更多
关键词 MAGNETITE NANOPARTICLES water SEDIMENTATION gradient Magnetic Field
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Seismic Attribute Gradient Analysis and Reservoir Configuration Study of Shallow Water Delta Reservoir in Huanghekou Sag
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作者 Jianmin Zhang Xijie Wang +3 位作者 Pengfei Mu Guokun Zhang Wei Guo Wen Zhang 《Open Journal of Applied Sciences》 CAS 2023年第5期696-703,共8页
The geological conditions of shallow offshore delta oil reservoirs are complex. Under the condition of less well data and larger well spacing, the traditional reservoir configuration method is difficult to solve the d... The geological conditions of shallow offshore delta oil reservoirs are complex. Under the condition of less well data and larger well spacing, the traditional reservoir configuration method is difficult to solve the detailed study of such reservoirs in offshore oil fields. Based on the comprehensive analysis of the seismic phase, data of well log. The paper identifies criteria of the quaternary configuration boundary in shallow water delta of different types with distributary sand dam is established. At the same time, this paper used sensitive factor to construct the edge detection operator based on the amplitude attribute, characterizing the boundary of sand body thickness mutation or physical property mutation quantitatively, realizing the quantitative characterization of four-stage configuration boundary in the region with no wells or few wells, guiding the efficient development of offshore shallow water delta oilfield, and realizing the increase of storage and production of Bohai oilfield. 展开更多
关键词 Shallow water Delta Reservoir Configuration Attribute gradient Attribute Fusion
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不同含水率与负温梯度下粉土冻结水分迁移特性
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作者 高峰 陈志德 +2 位作者 张军辉 郑健龙 盛岱超 《交通运输工程学报》 北大核心 2026年第1期200-210,共11页
为研究初始含水率及负温梯度对粉土冻结过程中水分迁移演变的影响,应用多物理场仿真软件COMSOL Multiphysics 6.0开展了5组不排水条件下的粉土冻结数值试验,重点分析了冻结全过程内冻深发展、温度场演化、未冻水分布、水分迁移通量及冻... 为研究初始含水率及负温梯度对粉土冻结过程中水分迁移演变的影响,应用多物理场仿真软件COMSOL Multiphysics 6.0开展了5组不排水条件下的粉土冻结数值试验,重点分析了冻结全过程内冻深发展、温度场演化、未冻水分布、水分迁移通量及冻胀变形的动态响应规律,揭示了二者对冻结水分迁移机制的综合影响。研究结果表明:粉土冻结过程具有明显的阶段特征,即冻结深度随时间呈先快速增长,后逐渐趋于稳定的变化趋势;负温梯度对冻结进程具有显著调控作用,增大负温梯度能够明显加快冻结锋面的推进速度,并使得最终稳定后的最大冻结深度显著增加,当负温梯度从12.5℃·m^(-1)提高至22.5℃·m^(-1)时,最大冻结深度增长约63%;冻结前后粉土含水率竖向分布发生显著变化,增大初始含水率和负温梯度导致未冻结区内发生更强烈的水分迁移现象,且峰值含水率随负温梯度增大发生更明显的向下偏移;冻结前期冻结锋面处水分不断得到来自下部未冻区的水分补给,是导致冻胀量快速增长的主要原因,随着冻结进程推进,水分迁移通量因温度场趋于稳定及未冻水含量降低而逐渐减弱,冻胀发展速率也随之下降,最终达到相对稳定的冻胀量。研究所得冻结土体水分迁移特性,结合当前共玉高速公路防排水处治措施的潜在局限,明确了阻断路基内部水分向上迁移对变形控制的重要性。 展开更多
关键词 路基工程 水分迁移 数值模拟 正冻粉土 冰水相变 负温梯度
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碱性电解水隔膜的梯度纳米复合策略构筑及性能
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作者 陈朴 高峰 +4 位作者 陈华 胡海兵 刘明芳 詹晓力 张庆华 《精细化工》 北大核心 2026年第3期486-493,共8页
为解决碱性电解水复合隔膜中纳米填料易脱落及低电阻与高气密性难以协同优化的问题,采用梯度纳米复合策略,以不同粒径分布(<100与200~400 nm)的ZrO_(2)为功能填料,通过相转化法制备了具有颗粒协同作用的多层级复合隔膜。通过面电阻... 为解决碱性电解水复合隔膜中纳米填料易脱落及低电阻与高气密性难以协同优化的问题,采用梯度纳米复合策略,以不同粒径分布(<100与200~400 nm)的ZrO_(2)为功能填料,通过相转化法制备了具有颗粒协同作用的多层级复合隔膜。通过面电阻、气泡点压力、力学性能等测试筛选出最佳复合质量比,并与商用Zirfon 500隔膜进行了电解性能对比。结果表明,当粒径<100 nm与粒径200~400 nm ZrO_(2)质量比为1∶2时,制备的隔膜(Z_(12))表面展现出纳米颗粒均匀分散的状态,在关键性能指标上实现了突破性平衡:面电阻低至0.267Ω·cm^(2),气泡点压力高达0.70 MPa,抗拉强度达13.413 MPa,同时具备优异的热稳定性与耐碱性;在1.9 V工作电压下,其电流密度(83.10 mA/cm^(2))较Zirfon 500膜(77.97 mA/cm^(2))提升5.13 mA/cm^(2);当膜厚优化降至220μm时制备的Z_(12)-220电流密度(93.98 mA/cm^(2))较Z_(12)增加了10.88 mA/cm^(2)。 展开更多
关键词 碱性电解水 梯度纳米复合策略 氧化锆 相转化法 面电阻 气泡点压力 功能材料
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海拔和水深梯度下高山湖泊藻类响应区域环境变化的长期模式识别
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作者 代平慧 陈光杰 +7 位作者 孔令阳 刘智 陈俊沅 马欠 王露 黄林培 李静 朱云 《生态学报》 北大核心 2026年第6期3092-3107,共16页
高海拔地区受人类活动直接干扰较少,区域气候变暖和大气沉降是影响高山湖泊环境和生态健康的重要因子。我国部分高山湖泊已经出现了明显的生态环境变化,因此对不同类型湖泊和生物指标开展对比分析已成为系统识别高山湖泊生态风险的关键... 高海拔地区受人类活动直接干扰较少,区域气候变暖和大气沉降是影响高山湖泊环境和生态健康的重要因子。我国部分高山湖泊已经出现了明显的生态环境变化,因此对不同类型湖泊和生物指标开展对比分析已成为系统识别高山湖泊生态风险的关键内容。选择滇西北地区6个高山湖泊为对象,通过沉积物粒度、总氮(TN)含量、氮稳定同位素及藻类(色素、硅藻)等多指标分析并结合历史资料,重建了近150年来湖泊环境与藻类的变化历史,重点识别了海拔和水深梯度下藻类数量与硅藻群落响应区域环境变化的模式异同及湖泊差异。三个深水湖泊中,丁公娘错藻类数量(叶绿素a色素浓度)没有明显变化,而盖公错纳和沃迪错的叶绿素a浓度持续上升;三个浅水湖泊中,属都湖的藻类数量逐渐上升,而丁公错和碧沽天池的叶绿素a浓度总体下降。方差分解分析表明,升温作用对沉积物叶绿素a浓度的驱动强度总体大于大气沉降作用(总氮含量),而对硅藻的驱动作用总体较弱。同时在水深梯度下,叶绿素a浓度与硅藻群落的变化特征存在明显的湖泊差异。其中,深水湖泊(丁公娘错、盖公错纳、沃迪错)的硅藻群落以小型浮游种为主,浅水湖泊(丁公错、属都湖、碧沽天池)以底栖种为主。丁公娘错的硅藻群落自1930年起发生明显转变,主要表现为小型浮游种(Pantocsekiella comensis)的快速上升;而盖公错纳和沃迪错的硅藻群落无显著变化。与深水湖泊不同,三个浅水湖泊的硅藻群落均出现了显著或多次变化。指标对比分析表明,藻类数量和硅藻群落结构总体呈现了较为一致的变化趋势。总之,在气候变暖和大气沉降的共同影响下高山湖泊藻类变化出现了异质性的区域模式,且在较低海拔和浅水型湖泊中存在更为敏感的响应特征。 展开更多
关键词 高山湖泊 藻类 硅藻 水深 气候变化 梯度效应
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水库消落带空间分异及其驱动因素——以四川省35座大型水库为例
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作者 万励 鲍玉海 +2 位作者 张浩哲 杨洁 贺秀斌 《长江流域资源与环境》 北大核心 2026年第1期215-229,共15页
水库消落带是陆地生态系统和水体生态系统交替作用区,明确消落带空间分布特征对库区生态环境保护和水库安全运行具有重要意义。以四川省35座大型水库消落带作为研究对象,对消落带在地形上的梯度分布、5 km缓冲区内消落带空间分异的驱动... 水库消落带是陆地生态系统和水体生态系统交替作用区,明确消落带空间分布特征对库区生态环境保护和水库安全运行具有重要意义。以四川省35座大型水库消落带作为研究对象,对消落带在地形上的梯度分布、5 km缓冲区内消落带空间分异的驱动因素进行分析,并且依次增大缓冲区范围探究其解释力q的变化。结果表明:(1)水位波动范围在低海拔、低坡度地区的消落带,主要在低梯度的区域出露;而对于高海拔、高坡度的区域,水库消落带梯度分布则较为均匀。(2)围绕消落带5 km缓冲区,利用最优参数地理探测器,发现影响消落带空间分异的驱动因素主要为地貌、年蒸发量和年均温度。(3)将缓冲区按5 km梯度依次扩大发现大部分因子的解释力q呈现下降趋势,表明其对消落带的影响存在距离上的依赖性。研究结果可为区域水库消落带生态修复、水库的运行管理等政策的制定提供数据支撑和理论依据。 展开更多
关键词 水库消落带 空间分异 梯度分布 最优参数地理探测器
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Photosynthetic and water-related physiological characteristics of Periploca sepium in response to changing soil water conditions in a shell sand habitat
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作者 Xiao Wang Jiangbao Xia +5 位作者 Ximei Zhao Mingming Dong Xianshuang Xing Ying Fang Qinqin Fu Zhaohua Lu 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第2期453-467,共15页
This study was performed to observe the effects of water on photosynthesis and water-related physiology in dominant shrubs in shell sand habitats.Four-year-old Periploca sepium seedlings were used as model species.A g... This study was performed to observe the effects of water on photosynthesis and water-related physiology in dominant shrubs in shell sand habitats.Four-year-old Periploca sepium seedlings were used as model species.A gradient of 12 water levels was established by artificially supplying the shell sand with water up to saturation and then allowing natural evapotranspiration to occur.The photo synthetic,chlorophyll fluorescence and stem sap flow parameters of P.sepium were measured under a range of water conditions.The different soil water conditions were classified according to the responses of these parameters.(1)With the increase in the relative water content(RWC)of the shell sand,the parameters of leaf photosynthesis,chlorophyll fluorescence and water-related physiology in P.sepium showed significant critical responses.The net photo synthetic rate(Pn),transpiration rate(Tr),instantaneous water use efficiency(WUE),potential water use efficiency(WUEi),maximum photochemical efficiency(Fv/Fm),actual photochemical efficiency(ΦPSII)and daily accumulation of stem sap flow all increased first and then decreased with increasing RWC,but the corresponding water conditions associated with their maximum values were not the same.An RWC of 69.40%was determined to be the optimal water condition for photosynthesis and water-related physiological activity in P.sepium.At an RWC of 36.61%,the mechanism of photosynthetic inhibition in P.sepium changed from stomatal limitation to nonstomatal limitation;this was also the minimum water requirement for maintaining normal photo synthetic processes.An RWC of 50.27%resulted in the highest WUE in P.sepium,indicating that moderate drought stress increased WUE.(2)Based on the quantitative relationship between the photo synthetic parameters of P.sepium and the shell sand water gradient,the soil water availability was classified into 6 water grades.The RWC range for maintaining strong photosynthesis and high WUE in P.sepium was 63.22-69.98%.(3)Gas exchange in P.sepium was inhibited under drought and waterlogging stresses.Under these conditions,the photosynthetic electron transport chain was blocked,and the dissipation of light energy as heat increased,which ultimately led to a decline in photo synthetic productivity;moreover,transpiration and dissipation were aggravated,and water transmission and utilization processes in P.sepium were hindered.A significant negative feedback regulation mechanism in the photosynthetic and water-related physiological processes of P.sepium was observed;this mechanism allowed P.sepium growing in shell sand to be highly adaptable to water stress. 展开更多
关键词 water gradient range Periploca sepium Photosynthesis water physiology water availability classifi cation Shell sand
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长江干堤穿堤管道渗流破坏机理及新型防渗结构研究
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作者 黄雍 崔皓东 +3 位作者 张培青 李鸣威 汪瑾杰 翁朝晖 《中国农村水利水电》 北大核心 2026年第2期160-165,共6页
随着我国能源基础设施的快速发展,穿堤管道工程规模逐年增长,施工扰动引发的堤基渗流破坏问题日益凸显。以2012年汛期长江干堤西气东输天然气管道穿越段突发管涌险情为例,针对传统防渗措施失效的难题,通过地质勘察、施工记录追溯及三维... 随着我国能源基础设施的快速发展,穿堤管道工程规模逐年增长,施工扰动引发的堤基渗流破坏问题日益凸显。以2012年汛期长江干堤西气东输天然气管道穿越段突发管涌险情为例,针对传统防渗措施失效的难题,通过地质勘察、施工记录追溯及三维渗流建模,系统揭示了险情发生致灾机理。针对本工程深层渗流、动水吸蚀与管道振动的复合工况,基于“分级消能、刚柔协同”的治理思路,研发了“刚性封堵+柔性缓冲”复合防渗结构,结构末端采用袋装碎石层减缓动水吸附压力,结合聚氨酯-沥青-油毡麻丝多层材料截断渗流路径,并通过局部盖重压浸与锥探灌浆强化浅层防护。该结构于2013年实施后,经2016年、2020年长江超警戒水位洪水考验,堤后无新增险情。研究证实:新型防渗结构通过多层协同作用有效阻断深层渗流通道,解决了传统加固措施的局限性,且具备抗震性、耐久性及经济性优势,案例成果为类似穿堤工程渗流灾害防控提供了技术支撑与工程范例。 展开更多
关键词 穿堤管道工程 管涌险情 渗流路径截断 多层止水结构 水力梯度 防洪安全
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老青山隧洞进口渐变段衬砌施工技术研究
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作者 杨连云 张兴凯 庄红云 《云南水力发电》 2026年第3期55-59,共5页
引水隧洞混凝土作为主体工程的重要组成部分,质量的优劣直接影响工程使用功能和结构安全,所以混凝土施工方案管理应该放在首位,须对混凝土施工工艺进行详细分析研究。滇中引水一期工程大理Ⅱ段施工5标老青山隧洞,长148.686 m,断面形式... 引水隧洞混凝土作为主体工程的重要组成部分,质量的优劣直接影响工程使用功能和结构安全,所以混凝土施工方案管理应该放在首位,须对混凝土施工工艺进行详细分析研究。滇中引水一期工程大理Ⅱ段施工5标老青山隧洞,长148.686 m,断面形式为城门形渐变为马蹄形,断面形式对混凝土施工工艺提出了较高要求;在方案设计时,科学有效的利用了BIM技术,进行工艺流程设计和脚手架计算等过程应用,保证了施工质量。 展开更多
关键词 引水隧洞 渐变段 滇中引水 混凝土 施工技术
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基于管段分组的供水管网漏损评估模型
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作者 李庚岩 赵梦珂 刘海星 《中国给水排水》 北大核心 2026年第5期63-68,共6页
针对供水管网基础数据集存在数据质量差问题,提出了基于管段分组的供水管网漏损评估方法,该方法考虑管段地理位置和属性特征进行分组,基于分组结果构建管段群组数据集,运用轻量级梯度提升机(LightGBM)算法,建立管段群组漏损评估模型,并... 针对供水管网基础数据集存在数据质量差问题,提出了基于管段分组的供水管网漏损评估方法,该方法考虑管段地理位置和属性特征进行分组,基于分组结果构建管段群组数据集,运用轻量级梯度提升机(LightGBM)算法,建立管段群组漏损评估模型,并将其应用于某市供水管网。结果表明,所构建的模型具有良好的性能,受试者工作特征曲线下面积(AUC)达到0.86以上;对比现有研究中管段漏损评估模型,管段群组漏损评估模型的性能更优,AUC增加了0.13;夏普利加性解释(SHAP)分析结果显示,管长、漏损时间间隔和历史漏损次数在漏损评估模型中是较重要的影响因素。 展开更多
关键词 供水管网 管段分组 轻量级梯度提升机(LightGBM)算法 漏损评估 夏普利加性解释(SHAP)
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基于渗漏-结构失稳-洞身变形协同治理的水库除险加固技术
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作者 刘琳楠 《工程技术研究》 2026年第2期54-56,共3页
以尚书水库除险加固工程为研究对象,针对其渗漏、结构失稳、洞身变形问题,建立多层次协同治理体系。监测数据显示,库水位周期性变化下,各坝肩断面渗压水头稳定,监测断面右坝肩、左坝肩、坝中的渗压极差分别为1.0 m、1.6 m、0.5 m,渗压... 以尚书水库除险加固工程为研究对象,针对其渗漏、结构失稳、洞身变形问题,建立多层次协同治理体系。监测数据显示,库水位周期性变化下,各坝肩断面渗压水头稳定,监测断面右坝肩、左坝肩、坝中的渗压极差分别为1.0 m、1.6 m、0.5 m,渗压梯度较为平缓;坝体沉降得到较好控制,各断面最大沉降量为7.9~9.3 mm,沉降分布均匀性较好(最大沉降差值仅为1.4 mm)。监测结果表明,该技术可显著提升坝区渗流场稳定性。 展开更多
关键词 水库 除险加固 协同治理 渗压水头 渗压梯度
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水滴在仿生润湿性梯度表面运动行为研究
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作者 钟兴海 魏洲洋 +2 位作者 姜喜旺 周广 苏敬文 《广州化工》 2026年第3期58-61,共4页
由于无需外部能量输入的优点,具有独特的液体自发性运动的功能表面已成为研究热点。然而驱动力不足导致的运输速度慢以及运输距离短,限制了其实际应用。受仙人掌利用锥状针刺实现液体收集和自发运输启发,在铜基底上加工出仿生楔形表面... 由于无需外部能量输入的优点,具有独特的液体自发性运动的功能表面已成为研究热点。然而驱动力不足导致的运输速度慢以及运输距离短,限制了其实际应用。受仙人掌利用锥状针刺实现液体收集和自发运输启发,在铜基底上加工出仿生楔形表面。水滴在润湿性梯度力和楔形表面产生的拉普拉斯压差的共同驱动下自发运动平均速度可达108.2 mm/s,改善了水滴在类似功能表面上运动性能不足的问题。得益于仿生润湿性梯度表面优异的液滴运输性能,在雨雾环境下展现了良好的雾收集效率,并且在微流控、细胞迁移和提高生物检测效率等领域具有广阔的应用前景。 展开更多
关键词 水滴运输 仿生表面 润湿性梯度 雾收集
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Relationships Between River Water Quality and Landscape Factors in Haihe River Basin, China: Implications for Environmental Management 被引量:4
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作者 XU Huashan ZHENG Hua +2 位作者 CHEN Xiaoshu REN Yufen OUYANG Zhiyun 《Chinese Geographical Science》 SCIE CSCD 2016年第2期197-207,共11页
River water plays a key role in human health, and in social and economic development, and is often affected by both natural factors and human activities. An in-depth understanding of the role of these factors can help... River water plays a key role in human health, and in social and economic development, and is often affected by both natural factors and human activities. An in-depth understanding of the role of these factors can help in developing an effective catchment management strategy to protect precious water resources. This study analyzed river water quality, patterns of terrestrial and riparian ecosystems, intensity of agricultural activities, industrial structure, and spatial distribution of pollutant emissions in the Haihe River Basin in China for the year of 2010, identifying the variables that have the greatest impact on river water quality. The area percentage of farmland in study area, the percentage of natural vegetation cover in the 1000-m riparian zone, rural population density, industrial Gross Domestic Product(GDP)/km^2, and industrial amino nitrogen emissions were all significantly correlated with river water quality(P < 0.05). Farming had the largest impact on river water quality, explaining 43.0% of the water quality variance, followed by the coverage of natural vegetation in the 1000-m riparian zone, which explained 36.2% of the water quality variance. Industrial amino nitrogen emissions intensity and rural population density explained 31.6% and 31.4% of the water quality variance, respectively, while industrial GDP/km^2 explained 26.6%. Together, these five indicators explained 67.3% of the total variance in water quality. Consequently, water environmental management of the Haihe River Basin should focus on adjusting agricultural activities, conserving riparian vegetation, and reducing industrial pollutant emissions by optimizing industrial structure. The results demonstrate how human activities drive the spatial pattern changes of river water quality, and they can provide reference for developing land use guidelines and for prioritizing management practices to maintain stream water quality in a large river basin. 展开更多
关键词 land use watershed management river water quality gradient analysis
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Application of PCR-DGGE in Research of Bacterial Diversity in Drinking Water 被引量:7
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作者 QING WU XIN-HUA ZHAO SHENG-YUE ZHAO 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2006年第5期371-374,共4页
Objective To analyze the structure of bacteria in drinking water by molecular biological techniques, Methods DNA of bacteria in drinking water was directly extracted without culture. 16S ribosomal DNA fragments, inclu... Objective To analyze the structure of bacteria in drinking water by molecular biological techniques, Methods DNA of bacteria in drinking water was directly extracted without culture. 16S ribosomal DNA fragments, including V-6, -7, and -8 regions, were amplified with universal primers (EUBf933CJC and EUBr1387) and analyzed by DGGE. Results DGGE indicated that amplification products could be separated, The results showed that DGGE could be used in the separation of different microbial 16SrRNA genes extracted from drinkng water. Though there were special bacteria in different water samples, the predominant bacteria were essentially the same. Three sequences of the reclaimed specific bands were obtained, and phylogenetic tree of these bands was made. Conclusion Bacterial diversity in drinking water is identified by molecular biological techniques. 展开更多
关键词 Drinking water Denaturing gradient gel electrophoresis (DGGE) 16S ribosome RNA Microbial diversity
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大庆外围油田低含水原油单管低温集输节能优化
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作者 修丽群 《石油石化节能与计量》 2026年第2期37-42,49,共7页
大庆外围油田采出液含水率范围一般为20%~60%,处于大庆原油反相点之前,与大庆老区高含水油田不同,外围油田采出液表观黏度随含水率升高而增大,多年来一直未确定一种投资低、运行能耗低且适应性强的集油工艺。因此,需要开展低含水原油集... 大庆外围油田采出液含水率范围一般为20%~60%,处于大庆原油反相点之前,与大庆老区高含水油田不同,外围油田采出液表观黏度随含水率升高而增大,多年来一直未确定一种投资低、运行能耗低且适应性强的集油工艺。因此,需要开展低含水原油集输工艺的适应性研究,将采出液室内环道实验与现场试验相结合,确定低含水含气原油单管常温集输界限。结合塔21-4区块8号平台的实际情况制定最佳集输方案:该平台需采取井口采出液加热到凝固点和管线维温的集输工艺;根据平台情况优化其运行参数,平台管线维温需控制在25~30℃,井口加热到的温度需控制在36~42℃,此时井口回压保持在0.4~0.8 MPa,进站温度保持在33~35℃,可满足油井正常生产需求。使用该最佳运行参数年节省耗电量8×10^(4)kWh、年节省投资5.6万元。该优化方案可有效指导高寒地区低含水油井单管低温集输运行与管理,达到节能降耗的目的。 展开更多
关键词 外围油田 低含水原油 单管低温集输 流速 含水率 压降梯度
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Experimental demonstration of influence of underwater turbulence on ghost imaging 被引量:4
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作者 Man-Qian Yin Le Wang Sheng-Mei Zhao 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第9期180-185,共6页
It is difficult to obtain a clear image in underwater turbulence environment with classical imaging methods due to the absorption, scattering, and underwater turbulence on the propagation beam.However, ghost imaging(G... It is difficult to obtain a clear image in underwater turbulence environment with classical imaging methods due to the absorption, scattering, and underwater turbulence on the propagation beam.However, ghost imaging(GI), a nonlocally imaging technique, has shown the turbulence-free ability in atmospheric turbulence by exploiting the second-order correlation between the signal beam and the reference beam.In this paper, we experimentally investigate the imaging quality of GI affected by the underwater environment, where the underwater environment is simulated by a 1 m×0.4 m×0.4 m tank with distilled water.The water temperature is controlled by a heater inside the tank, and a temperature gradient is obtained by putting the heater at different positions of the tank.The water vibration is produced by a heavy force, and the turbid medium is obtained by dissolving very small specks of CaCO3 in the water.A set of Hadamard speckle pattern pairs are generated and modulated on the incident beam, and then the beam illuminates on an unknown object after passing through the simulated underwater environment.With the second-order correlations, the image is reconstructed under different temperature gradients, water vibration, and turbid medium ratios.The results show that GI has the turbulence-free ability under lower temperature gradient, water vibration, and turbid media.The structural similarity image measurement(SSIM)values of the reconstructed images only start to decrease when the temperature gradient is greater than 4.0℃.The same temperature gradient produced at the different positions has a little effect on the quality of the underwater GI. 展开更多
关键词 UNDERwater GHOST imaging temperature gradient turbid MEDIA water vibration
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基于PageRank算法的城市配水管网管段改造比选排序设计
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作者 巩建军 《中国水能及电气化》 2026年第4期52-56,共5页
针对城市配水管网管段改造中存在的比选排序与经济效益优化问题,提出一种基于PageRank算法改进的MPR-Pipe算法。该算法通过求解管网节点与管段多种水力属性的PageRank值,构建了以经济流量与单位水力坡降为基础的管段重要性度量指标。该... 针对城市配水管网管段改造中存在的比选排序与经济效益优化问题,提出一种基于PageRank算法改进的MPR-Pipe算法。该算法通过求解管网节点与管段多种水力属性的PageRank值,构建了以经济流量与单位水力坡降为基础的管段重要性度量指标。该指标能够有效表征管段实际运行流量偏离经济流量的程度,并作为管段改造优先级排序的依据。理论分析表明,所提算法具有较高的求解效率。实际应用结果显示,MPR-Pipe算法能够准确识别并优先排序实际流量远超经济流量、单位水力坡降较大的关键瓶颈管段,为管网改造提供科学依据。 展开更多
关键词 配水管网 管段改造 单位水力坡度 比选 PAGERANK算法
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WATER TRANSPORT IN WOOD PARTICLE MATERIAL
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作者 Shang DckuNortheast Forestry University, Harbin 150040, P.R.China 《Journal of Northeast Forestry University》 SCIE CAS CSCD 1990年第1期79-85,共7页
An analogy between water flux and the field of temperature gradient in a column of wood fuel chips was discovered by these experiments.The heat-mass transfer coeffieient was deter-mined by least squares method.An equa... An analogy between water flux and the field of temperature gradient in a column of wood fuel chips was discovered by these experiments.The heat-mass transfer coeffieient was deter-mined by least squares method.An equation relating water flux and tempetature gradient was devel-opcd and it was demonstrated that the tempeature gradient was the main driving force for watertransport.The meehanism was evaporation-condensation of water vaor through natural convcctionin air phase.The study gives a theoretical exlanation for analyzing the problem of water transport inwood particle material. 展开更多
关键词 WOOD FUEL CHIPS water FLUX Temperature gradient ANALOGY
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