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北方旱区农田水肥效应分析

高亚军,李生秀

《中国工程科学》 2002年 第4卷 第7期   页码 74-79

摘要：

结合多年的田间试验研究，对前人诸多研究结果进行了总结和深入分析。结果表明：农田水肥效应大小与试验方法有关，田间试验与模拟试验得到的结论相反。主要原因在于研究中"水"的概念各不相同，从旱棚试验或盆栽试验的结果推断水肥效应与实际情况相距较大。多数情况下，养分亏缺仍是北方旱区作物增产的主要限制因子。灌水的效果取决于土壤底墒、生育期降水、土壤肥力及灌水时期等各种因素。在现有的水资源条件下，提高养分供应水平是北方旱区大部分农田作物增产的主要途径。加强夏闲期降水的蓄积、提高土壤底墒是冬麦区作物高产的重要条件。

关键词： 水肥效应     北方旱区     田间试验     模拟试验    

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Field experiment on biological contact oxidation process to treat polluted river water in the Dianchi

Lu LI, Shuguang XIE, Hui ZHANG, Donghui WEN

《环境科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 38-47 doi: 10.1007/s11783-009-0007-6

摘要： In this study two types of biological contact oxidation processes (BCOP), a step-feed (SBCOP) unit and an inter-recycle (IBCOP) unit, were designed to investigate the treatment of heavily polluted river water. The Daqing River, which is the largest pollutant contributor to the Dianchi Lake, one of the most eutrophic freshwater lakes in China, was taken for the case study. It was found that the SBCOP had higher adaptability and better performance in the reduction of COD, TN, and TP, which made it applicable for the treatment of polluted river water entering the Dianchi Lake. Nitrification rate was observed to be greatly affected by the influent temperature. During each season, the nitrification in the SBCOP was higher than that in the IBCOP. TN removal efficiency in the SBCOP was higher than that in the IBCOP during the winter and spring but poorer during the summer, possibly due to the inhibition of denitrification by higher dissolved oxygen level in the summer. Moreover, symbiotic algae-bacteria growth may be conducive to the removal of pollutants.

关键词： step-feed biological contact oxidation process (SBCOP)     inter-recycle biological contact oxidation process (IBCOP)     river water     removal efficiency     nitrogen transformation     the Dianchi Lake watershed    

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ENHANCING RAINFALL-RUNOFF POLLUTION MODELING BY INCORPORATION OF NEGLECTED PHYSICAL PROCESSES

《农业科学与工程前沿（英文）》 2023年 第10卷 第4期   页码 553-565 doi: 10.15302/J-FASE-2023519

摘要：

The growing need to mitigate rainfall-runoff pollution, especially first flush, calls for accurate quantification of pollution load and the refined understanding of its spatial-temporal variation. The wash-off model has advantages in modeling rainfall-runoff pollution due to the inclusion of two key physical processes, build-up and wash-off. However, this disregards pollution load from wet precipitation and the relationship between rainfall and runoff, leading to uncertainties in model outputs. This study integrated the Soil Conservation Service curve number (SCS-CN) into the wash-off model and added pollutant load from wet precipitation to enhance the rainfall-runoff pollution modeling. The enhanced wash-off model was validated in a typical rural-residential area. The results showed that the model performed better than the established wash-off model and the commonly-used event mean concentrations method, and identified two different modes of pollution characteristics dominated by land pollution and rainfall pollution, respectively. In addition, the model simulated more accurate pollutant concentrations at high-temporal-resolution. From this, it was found that 12% of the total runoff contained 80% to 95% of the total load for chemical oxygen demand, total N, and total P, whereas it contained only 15% of the total load for NH4+-N. The enhanced model can provide deeper insights into non-point pollution mitigation.

关键词： Erhai Lake     field experiment     non-point source     pollution load     rainfall runoff     wash-off model    

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Full scale amendment of a contaminated wood impregnation site with iron water treatment residues

Sanne Skov NIELSEN, Peter KJELDSEN, Rasmus JAKOBSEN

《环境科学与工程前沿（英文）》 2016年 第10卷 第4期 doi: 10.1007/s11783-016-0842-1

摘要： Iron water treatment residues are a free by-product with high concentration of iron oxides Iron water treatment residues has a large potential for arsenic sorption Soils are highly contaminated by arsenic at wood preservation sites Iron water treatment residues were added to hot spots contaminated with arsenic The addition led to significant decrease in leaching of arsenic from the contaminated soil Iron water treatment residues (Fe-WTR) are a free by-product of the treatment of drinking water with high concentration of iron oxides and potential for arsenic sorption. This paper aims at applying Fe-WTR to a contaminated site, measuring the reduction in contaminant leaching, and discussing the design of delivery and mixing strategy for soil stabilization at field scale and present a cost-effective method of soil mixing by common contractor machinery. Soil contaminated by As, Cr, and Cu at an abandoned wood impregnation site was amended with 0.22% (dw) Fe-WTR. To evaluate the full scale amendment a 100 m test site and a control site (without amendment) were monitored for 14 months. Also soil analysis of Fe to evaluate the degree of soil and Fe-WTR mixing was done. Stabilization with Fe-WTR had a significant effect on leachable contaminants, reducing pore water As by 93%, Cu by 91% and Cr by 95% in the upper samplers. Dosage and mixing of Fe-WTR in the soil proved to be difficult in the deeper part of the field, and pore water concentrations of arsenic was generally higher. Despite water logged conditions no increase in dissolved iron or arsenic was observed in the amended soil. Our field scale amendment of contaminated soil was overall successful in decreasing leaching of As, Cr and Cu. With minor improvements in the mixing and delivery strategy, this stabilization method is suggested for use in cases, where leaching of Cu, Cr and As constitutes a risk for groundwater and freshwater.

关键词： Field experiment     Iron oxide     Arsenic     Stabilization     Wood preservation sites    

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Design and experiment of a novel pneumatic soft arm based on a deployable origami exoskeleton

《机械工程前沿（英文）》 2023年 第18卷 第4期 doi: 10.1007/s11465-023-0770-2

摘要： Soft arms have shown great application potential because of their flexibility and compliance in unstructured environments. However, soft arms made from soft materials exhibit limited cargo-loading capacity, which restricts their ability to manipulate objects. In this research, a novel soft arm was developed by coupling a rigid origami exoskeleton with soft airbags. The joint module of the soft arm was composed of a deployable origami exoskeleton and three soft airbags. The motion and load performance of the soft arm of the eight-joint module was tested. The developed soft arm withstood at least 5 kg of load during extension, contraction, and bending motions; exhibited bistable characteristics in both fully contracted and fully extended states; and achieved a bending angle of more than 240° and a contraction ratio of more than 300%. In addition, the high extension, contraction, bending, and torsional stiffnesses of the soft arm were experimentally demonstrated. A kinematic-based trajectory planning of the soft arm was performed to evaluate its error in repetitive motion. This work will provide new design ideas and methods for flexible manipulation applications of soft arms.

关键词： pneumatic soft arm     soft airbag     deployable origami exoskeleton     bistable characteristics     cargo-loading capacity    

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Atmospheric heterogeneous reaction of chlorobenzene on mineral -FeO particulates: a chamber experiment

《环境科学与工程前沿（英文）》 2023年 第17卷 第11期 doi: 10.1007/s11783-023-1734-9

摘要：

● Photochemical conversion of chlorobenzene (CB) on α-Fe2O3 was evaluated.

关键词： Photochemical conversion     Chlorobenzene     α-Fe2O3     PCDD/Fs     Mineral particulate    

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Biaxial tensile-compressive experiment of concrete at high temperatures

SONG Yupu, ZHANG Zhong, QING Likun, YU Changjiang

《结构与土木工程前沿（英文）》 2007年 第1卷 第1期   页码 94-98 doi: 10.1007/s11709-007-0009-z

摘要： Biaxial tension-compression experiments of concrete of five stress ratios at high temperatures were carried out using the large static-dynamic triaxial test system in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology. The stress ratios s1/s3 are 0, 0.1, 0.25, 0.50, and 0.75. The temperatures are 20vH, 200vH, 300vH, 500vH, 600vH. The mechanical behavior of concrete under biaxial tension-compression at high temperatures is analyzed. It is found that both the tensile strength and strain diminished with the increase in temperature under each stress ratio. Based on the test results, the relationship between tensile strengths and stress ratios and temperature is proposed. In addition, the failure criterion of concrete under biaxial stress state of tension-compression at high temperatures is established.

关键词： increase     Offshore Engineering     temperature     relationship     addition    

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Numerical simulation and experiment research of radiation performance in a dish solar collector system

Yong SHUAI, Xinlin XIA, Heping TAN

《能源前沿（英文）》 2010年 第4卷 第4期   页码 488-495 doi: 10.1007/s11708-010-0007-z

摘要： The Monte Carlo ray-tracing method is applied and coupled with optical properties to predict the radiation performance of solar concentrator/cavity receiver systems. Several different cavity geometries are compared on the radiation performance. A flux density distribution measurement system for dish parabolic concentrators is developed. The contours of the flux distribution for target placements at different distances from the dish vertex of a solar concentrator are taken by using an indirect method with a Lambert and a charge coupled device (CCD) camera. Further, the measured flux distributions are compared with a Monte Carlo-predicted distribution. The results can be a valuable reference for the design and assemblage of the solar collector system.

关键词： Monte Carlo method     solar energy     radiation performance     cavity receiver    

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Centrifuge experiment and numerical analysis of an air-backed plate subjected to underwater shock loading

Zhijie HUANG, Xiaodan REN, Zuyu CHEN, Daosheng LING

《结构与土木工程前沿（英文）》 2019年 第13卷 第6期   页码 1350-1362 doi: 10.1007/s11709-019-0559-x

摘要： In this study, systematic centrifuge experiments and numerical studies are conducted to investigate the effect of shock loads due to an underwater explosion on the dynamic responses of an air-backed steel plate. Numerical simulations with three different models of pressure time history generated by underwater explosion were carried out. The first model of pressure time history was measured in test. The second model to predict the time history of shock wave pressure from an underwater explosion was created by Cole in 1948. Coefficients of Cole’s formulas are determined experimentally. The third model was developed by Zamyshlyaev and Yakovlev in 1973. All of them are implemented into the numerical model to calculate the shock responses of the plate. Simulated peak strains obtained from the three models are compared with the experimental results, yielding average relative differences of 21.39%, 45.73%, and 13.92%, respectively. The Russell error technique is used to quantitatively analyze the correlation between the numerical and experimental results. Quantitative analysis shows that the simulated strains for most measurement points on the steel plate are acceptable. By changing the scaled distances, different shock impulses were obtained and exerted on the steel plate. Systematic numerical studies are performed to investigate the effect of the accumulated shock impulse on the peak strains. The numerical and experimental results suggest that the peak strains are strongly dependent on the accumulated shock impulse.

关键词： underwater explosion     centrifuge experiment     shock load     dynamic response     accumulated shock impulse    

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Parameter for judging reactivity of coal and coke

HE Hongzhou, LUO Zhongyang, CEN Kefa

《能源前沿（英文）》 2008年 第2卷 第3期   页码 354-358 doi: 10.1007/s11708-008-0052-z

摘要： To eliminate the judgment error of char reactivity arising from different carbon content of samples, a new parameter called specific maximum weight loss rate was introduced. It is defined as the quotient of the maximum weight loss rate in non-isothermal thermogravimetric analysis (TGA) experiment to the carbon content of the corresponding sample. The reactivity of different kinds of coal, the reactivity of the same coal type with different lithotype, and the reactivity of the char with different carbon conversion rates were checked by using the specific maximum weight loss rate, and the results were analyzed and compared with those obtained by using other criteria. The results show that the specific maximum weight loss rate can be used as a commonality parameter to evaluate and distinguish the reactivity of different coal and char. The heating rate selected in TGA experiment has no effect on the judgment.

关键词： thermogravimetric analysis     specific maximum     different lithotype     experiment     TGA experiment    

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How did Archimedes discover the law of buoyancy by experiment?

Hidetaka KUROKI

《机械工程前沿（英文）》 2016年 第11卷 第1期   页码 26-32 doi: 10.1007/s11465-016-0368-z

摘要：

After Archimedes and Vitruvius era, for more than 2000 years, it has been believed that the displaced water measurement of golden crown is impossible, and at his Eureka moment, Archimedes discovered the law of buoyancy (Proposition 7 of his principles) and proved the theft of a goldsmith by weighing the golden crown in water.

A previous study showed that a small amount of displaced water was able to be measured with enough accuracy by the introduced method. Archimedes measured the weight of displaced water. He did not find the law of buoyancy but rather specific gravity of things at the moment.

After which, Archimedes continued to measure the specific gravity of various solids and fluids. Through these measurements, he reached the discovery of the law of buoyancy directly by experiment. In this paper, the process to the discovery of Archimedes’ principle (Proposition 5) is presented.

关键词： Archimedes’ principle     buoyancy     specific gravity     Eureka     Vitruvius     displaced water     balance     floating body    

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Analysis and experiment on structure parameters for an energy reclaiming suspension

CHEN Shi‘an, HE Ren, LU Senlin

《机械工程前沿（英文）》 2008年 第3卷 第2期   页码 200-204 doi: 10.1007/s11465-008-0024-3

摘要： An energy reclaiming suspension is proposed to reclaim vibration energy in the suspension. To study its riding performance and reclaiming energy performance, a hydraulic energy reclaiming device prototype is produced and its mechanical behavior is analyzed and tested according to the hydraulic theory. Theoretical analysis shows that mechanical behavior of the energy reclaiming device is embodied by a viscidity damping parameter and an analogous coulomb damping parameter determined by its structure; their expressions are obtained. Experimental investigation shows that theoretical predictions agree with test results.

关键词： Experimental investigation     analogous coulomb     hydraulic     performance     suspension    

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Recent progress in electric-field assisted combustion: a brief review

《能源前沿（英文）》 2022年 第16卷 第6期   页码 883-899 doi: 10.1007/s11708-021-0770-z

摘要： The control of combustion is a hot and classical topic. Among the combustion technologies, electric-field assisted combustion is an advanced techno-logy that enjoys major advantages such as fast response and low power consumption compared with thermal power. However, its fundamental principle and impacts on the flames are complicated due to the coupling between physics, chemistry, and electromagnetics. In the last two decades, tremendous efforts have been made to understand electric-field assisted combustion. New observations have been reported based on different combustion systems and improved diagnostics. The main impacts, including flame stabilization, emission reduction, and flame propagation, have been revealed by both simulative and experimental studies. These findings significantly facilitate the application of electric-field assisted combustion. This brief review is intended to provide a comprehensive overview of the recent progress of this combustion technology and further point out research opportunities worth investigation.

关键词： electric field     combustion     flame stabilization     emission reduction     flame propagation    

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Analysis and experiment of controllability of magnetorheological fluids based on micro-pipeline

Yongqing SU, Yikuan SONG, Jiguang YUE

《机械工程前沿（英文）》 2009年 第4卷 第3期   页码 339-344 doi: 10.1007/s11465-009-0048-3

摘要： The controllability of the magneto-rheological fluid (MRF) flowing through a micro-pipeline is analyzed. The coupled formulas for MRF are deduced by analyzing the property of the flow field and magnetic field. Then, the relationship between the flow speed of MRF and the special shear stress under the effect of the magnetic field is founded. The model of the MRF and micro-pipeline is established by using multi-physics software of Comsol, the curve of - in an ideal condition is attained by modifying parameters, and by adding the boundary condition of the model. This paper provides a theoretical proof of the controllability of MRF flowing through the micro-pipeline and explores MRF’s application on the micro-drive and control field.

关键词： Magneto-rheological fluids (MRF)     micro-pipeline     coupled model     multi-physics simulation    

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A MATLAB code for the material-field series-expansion topology optimization method

《机械工程前沿（英文）》 2021年 第16卷 第3期   页码 607-622 doi: 10.1007/s11465-021-0637-3

摘要： This paper presents a MATLAB implementation of the material-field series-expansion (MFSE) topo-logy optimization method. The MFSE method uses a bounded material field with specified spatial correlation to represent the structural topology. With the series-expansion method for bounded fields, this material field is described with the characteristic base functions and the corresponding coefficients. Compared with the conventional density-based method, the MFSE method decouples the topological description and the finite element discretization, and greatly reduces the number of design variables after dimensionality reduction. Other features of this method include inherent control on structural topological complexity, crisp structural boundary description, mesh independence, and being free from the checkerboard pattern. With the focus on the implementation of the MFSE method, the present MATLAB code uses the maximum stiffness optimization problems solved with a gradient-based optimizer as examples. The MATLAB code consists of three parts, namely, the main program and two subroutines (one for aggregating the optimization constraints and the other about the method of moving asymptotes optimizer). The implementation of the code and its extensions to topology optimization problems with multiple load cases and passive elements are discussed in detail. The code is intended for researchers who are interested in this method and want to get started with it quickly. It can also be used as a basis for handling complex engineering optimization problems by combining the MFSE topology optimization method with non-gradient optimization algorithms without sensitivity information because only a few design variables are required to describe relatively complex structural topology and smooth structural boundaries using the MFSE method.

关键词： MATLAB implementation     topology optimization     material-field series-expansion method     bounded material field     dimensionality reduction    

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标题 作者 时间 类型 操作

北方旱区农田水肥效应分析

高亚军,李生秀

期刊论文

Field experiment on biological contact oxidation process to treat polluted river water in the Dianchi

Lu LI, Shuguang XIE, Hui ZHANG, Donghui WEN

期刊论文

ENHANCING RAINFALL-RUNOFF POLLUTION MODELING BY INCORPORATION OF NEGLECTED PHYSICAL PROCESSES

期刊论文

Full scale amendment of a contaminated wood impregnation site with iron water treatment residues

Sanne Skov NIELSEN, Peter KJELDSEN, Rasmus JAKOBSEN

期刊论文

Design and experiment of a novel pneumatic soft arm based on a deployable origami exoskeleton

期刊论文

Atmospheric heterogeneous reaction of chlorobenzene on mineral -FeO particulates: a chamber experiment

期刊论文

Biaxial tensile-compressive experiment of concrete at high temperatures

SONG Yupu, ZHANG Zhong, QING Likun, YU Changjiang

期刊论文

Numerical simulation and experiment research of radiation performance in a dish solar collector system

Yong SHUAI, Xinlin XIA, Heping TAN

期刊论文

Centrifuge experiment and numerical analysis of an air-backed plate subjected to underwater shock loading

Zhijie HUANG, Xiaodan REN, Zuyu CHEN, Daosheng LING

期刊论文

Parameter for judging reactivity of coal and coke

HE Hongzhou, LUO Zhongyang, CEN Kefa

期刊论文

How did Archimedes discover the law of buoyancy by experiment?

Hidetaka KUROKI

期刊论文

Analysis and experiment on structure parameters for an energy reclaiming suspension

CHEN Shi‘an, HE Ren, LU Senlin

期刊论文

Recent progress in electric-field assisted combustion: a brief review

期刊论文

Analysis and experiment of controllability of magnetorheological fluids based on micro-pipeline

Yongqing SU, Yikuan SONG, Jiguang YUE

期刊论文

A MATLAB code for the material-field series-expansion topology optimization method

期刊论文