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Effects of free iron oxyhydrates and soil organic matter on copper sorption-desorption behavior by size fractions of aggregates from two paddy soils

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Journal of Environmental Sciences 2009年第5期21卷 618-624页

作者： WANG Fang, PAN Genxing, LI Lianqing institute of Resource, ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing 210095, China. institute of Resource Ecosystem and Environment of Agriculture Nanjing Agricultural University Nanjing 210095 China

Effects of free iron oxyhydrates （Fed） and soil organic matter （SOM） on copper （Cu^2＋） sorption-desorption behavior by size fractions of aggregates from two typical paddy soils （Ferric-Accumulic Stagnic Anthrosol （Soil H） and Gleyic Stagnic Anthrosol （Soil W）） were investigated with and without treatments of dithionite-citrate-bicarbonate and of H2O2. The size fractions of aggregates were obtained from the undisturbed bulk topsoil using a low energy ultrasonic dispersion procedure. Experiments of equilibrium sorption and subsequent desorption were conducted at soil water ratio of 1：20, 25℃. For Soil H, Cu^2＋ sorption capacity of the DCB-treated size fractions was decreased by 5.9% for fine sand fraction, by 40.4% for coarse sand fraction, in comparison to 2.9% for the bnlk sample. However, Cu^2＋ sorption capacities of the H2O2-treated fractions were decreased by over 80% for the coarse sand fraction and by 15% for the clay-sized fraction in comparison to 88% for bulk soil. For Soil W, Cu^2＋ sorption capacity of the DCB-treated size fraction was decreased by 30% for the coarse sand fraction and by over 75% for silt sand fraction in comparison to 44.5% for the bulk sample. Cu^2＋ sorption capacities of the H2O2-treated fractions were decreased by only 2.0% for the coarse sand fraction and by 15% for the fine sand fraction in comparison to by 3.4% for bulk soil. However, Cu^2＋ desorption rates were increased much in H2O2-treated samples by over 80% except the clay-sized fraction （only 9.5%） for Soil H. While removal of SOM with H2O2 tendend to increase the desorption rate, DCB- and H2O2-treatments caused decrease in Cu^2＋ retention capacity of size fractions, Particularly, there hardly remained Cu^2＋ retention capacity by size fractions from Soil H after H2O2 treatment except for clay-sized fraction. These findings supported again the dominance of the coarse sand fraction in sorption of metals and the preference of absorbed metals bound to SOM in differently stabilized

关键词： paddy soils Cn^2+ sorption-desorption soil organic matter free iron oxyhydrates size fraction of aggregates

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Recasting theory of elasticity with micro-finite elements

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Acta Mechanica Sinica 2015年第5期31卷 679-684页

作者： Wennan Zou institute for Advanced study Nanchang University

In the classical theory of elasticity,a body is initially modeled as a homogeneous and dense assemblage of constituent ＂material particles＂.The kernel concept of elastic deformation is the displacement of the particle that associates the current configuration with the reference *** this paper,we exploit an alternative constituent ＂micro-finite element＂,and use the stretch of the element as the essential quality to recast the theory of *** should be realized that such a treatment means that the elastic body can be modeled as a finite covering of elements and consequently characterized by a *** recasting of the elasticity theory becomes more feasible for dealing with defects and topological evolution.

关键词： Micro-finite element Stretch Displacement Relative rotation Compatibility condition

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超小金纳米粒子的近红外二区发光增强与生物医学应用（英文）

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Science China Materials 2025年第1期 86-104页

作者：周廷尧李正 institute for Advanced study Shenzhen University

超小金纳米粒子(AuNPs, d <3 nm)因其可调的发光特性、优越的药代动力学、低毒性和丰富的表面化学,已成为一种优异的诊疗纳米探针.近红外二区(NIR-Ⅱ)发光具有独特的优势,如深层组织穿透、高空间分辨率和信噪比,为超小AuNPs的先进生物...

超小金纳米粒子(AuNPs, d <3 nm)因其可调的发光特性、优越的药代动力学、低毒性和丰富的表面化学,已成为一种优异的诊疗纳米探针.近红外二区(NIR-Ⅱ)发光具有独特的优势,如深层组织穿透、高空间分辨率和信噪比,为超小AuNPs的先进生物医学应用提供了多种机遇与挑战.在此,本文回顾了超小AuNPs在NIR-Ⅱ发光机制、清除途径及相关生物医学方面的最新研究进展.本文首先阐明了超小AuNPs NIR-Ⅱ的发光机理,以及增强NIR-Ⅱ的发光策略.然后,讨论了它们的结构对肝和肾清除的影响.文章还总结了超小AuNPs在生物成像、抗菌、药物递送等方面的应用.最后,我们展望了超小AuNPs在未来面临的机遇与挑战.

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Topsoil organic carbon mineralization and CO_2 evolution of three paddy soils from South China and the temperature dependence

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Journal of Environmental Sciences 2007年第3期19卷 319-326页

作者： ZHANG Xu-hui LI Lian-qing PAN Gen-xing institute of Resources Ecosystem and Environment of Agriculture Nanjing Agricultural University Nanjing 210095 China.

Carbon mineralization and its response to climatic warming have been receiving global attention for the last decade. Although the virtual influence of temperature effect is still in great debate, little is known on the mineralization of organic carbon （SOC） of paddy soils of China under warming. SOC mineralization of three major types of China＇s paddy soils is studied through laboratory incubation for 114 d under soil moisture regime of 70% water holding capacity at 20℃ and 25℃ respectively. The carbon that mineralized as CO2 evolved was measured every day in the first 32 d and every two days in the following days. Carbon mineralized during the 114 d incubation ranged from 3.51 to 9.22 mg CO2-C/gC at 20℃ and from 4.24 to 11.35 mg CO2-C/gC at 25℃ respectively; and a mineralizable C pool in the range of 0.24 to 0.59 gC/kg, varying with different soils. The whole course of C mineralization in the 114 d incubation could be divided into three stages of varying rates, representing the three subpools of the total mineralizable C： very actively mineralized C at 1-23 d, actively tnineralized C at 24--74 d and a slowly mineralized pool with low and more or less stabilized C mineralization rate at 75-114 d. The calculated Q10 values ranged from 1.0 to 2.4, varying with the soil types and N status. Neither the total SOC pool nor the labile C pool could account for the total mineralization potential of the soils studied, despite a well correlation of labile C with the shortly and actively mineralized C, which were shown in sensitive response to soil warming. However, the portion of microbial C pool and the soil C/N ratio controlled the C mineralization and the temperature dependence. Therefore, C sequestration may not result in an increase of C mineralization proportionally. The relative control of C bioavailability and microbial metabolic activity on C mineralization with respect to stabilization of sequestered C in the paddy soils of China is to be further studied.

关键词： C mineralization carbon pool laboratory incubation paddy soil soil warming

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Sorption of pyrene on two paddy soils and their particle-size fractions

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Journal of Environmental Sciences 2005年第6期17卷 962-965页

作者： LI Jiu-hai PAN Gen-xing institute of Resources Ecosystem and Environment of Agriculture Nanjing Agricultural University Nanjing 210095 China

In the present study, the sorption of pyrene on two kinds of bulk paddy soils, Gleyic Stagnic Anthrosols, and Ferric accumulic Stagnic Anthrosols as well as their particle-size fractions was investigated. The sorption isotherms fitted well with Freundlich equation. For both soils, the clay fraction（〈 2μm） and coarse sand fraction（2000-250μm） had higher sorption capacity than fine sand fraction（250-20 μm） and silt fraction（20-2 μm）. The IogKoc values obtained of each soil and its particle-size fractions were similar, proving that SOM content was a key factor affecting pyrene sorption. The Kd values showed a significant correlation with contents of dithionite-extractable Fe in both paddy soils and a good relationship with CEC in Gleyic Stagnic Anthrosols, indicating possible effects of surface properties of particle-size fractions on the sorption of pyrene.

关键词： paddy soil particle-size fraction PAHs sorption

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Variation of grain Cd and Zn concentrations of 110 hybrid rice cultivars grown in a low-Cd paddy soil

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Journal of Environmental Sciences 2009年第2期21卷 168-172页

作者： SHI Jing,LI Lianqing,PAN Genxing institute of Resource,ecosystem and Environment of Agriculture,Nanjing Agricultural University,Nanjing 210095,China. institute of Resource Ecosystem and Environment of Agriculture Nanjing Agricultural University Nanjing 210095 China

Enhanced Cd uptake and Zn depletion in rice grains and high potential for food Cd exposure by the high-yielding hybrid cultivars of China had been addressed. A field experiment was conducted in 2006 to determine the difference in grain Cd and Zn between cultivars. Total 110 cultivars including super rice and common hybrid rice cultivars were grown on a single paddy soil （Entic Haplaquept） with a neutral reaction and low total Cd content. Grain Cd and Zn concentrations were determined with graphite atomic adsorption spectrophotometer （GFAAS） and flame atomic adsorption spectrophotometer （AAS） respectively. Wide variation of Cd content in grain was found in a range of 0.004-0.057 mg/kg, while the Zn content in a range of 10.25-30.06 mg/kg among the cultivars. Higher Cd but lower Zn concentration in grains of super rice cultivars was observed compared to the common hybrid ones. A highly significant positive linear correlation of grain Cd/Zn with grain Cd was found for super rice and common hybrid cultivars, meanwhile much higher slope for these hybrid cultivars than the reported non-hybrid cultivars was also observed. Using the limit value of the Chinese chemical guidelines for foods （MOHC and SSC, 2005）, calculated potential risk of food Cd exposure with ＂Zn hungry＂ through diet intake was prominent with all the studied 110 hybrid rice cultivars, possessing high potential health problems for rice production in South China using the super rice cultivars. Breeding of genotypes of rice cultivars with low grain Cd and low Cd/Zn ratio is needed for rice production in acidic red soils where Cd bioavailability is prevalently high.

关键词： rice cultivar rice grain cadmium zinc genotype difference

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High ecostoichiometric stability and accumulating SiO2 and NO3- as main physiological adaptive mechanisms for reed to adverse environments

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Research in Cold and Arid Regions 2024年第5期16卷 250-258页

作者： JianJun Kang Fan Yang DongMei Zhang LiWen Zhao Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands Linze Inland River Basin Research Station Chinese Ecosystem Research NetworkNorthwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Minqin National Studies Station for Desert Steppe ecosystem Gansu Desert Control Research Institute

Previous studies have shown that nutrients accumulation played important roles in resisting to stress resistance of *** study examined the ecostoichiometric internal stability （EIS） of nutrients accumulation and,concomitantly identified the main resistant regulating substances and their contributions to stress resistance of reed （Gramineae） in arid desert *** （digging method） and soil samples （quartering method）) obtained from sand dune （SD）,desert steppe （DP）,interdune lowland （IL）,saline meadow （SM） and wetland （W） habitats were brought back to the lab for nutrients *** indicated that soil nutrients differed obviously,while reed maintained relatively stable ratios of SiO2:N,N:K,and P:K when the eco-environments changed in different ***,reed exhibits common adaptive characteristics by mainly accumulating large amounts of SiO2（122.6–174.0 g/kg） and NO3-（166.1–216.6 g/kg）,as well as moderate levels of soluble sugar （SS:24.0–55.0 g/kg）,which are mainly stored in leaves for stress *** contribution of ions to stress resistance was 80.03%–91.15%（with SiO2and NO3-accounting for 54.91%–63.10%）,whereas the contribution of solutes was only 8.85%–19.97%（with SS contributing to 5.14%–10.91%） in different *** findings suggest that maintaining relatively high EIS,while still accumulating SiO2and NO3-as main physiological regulators might be an effective strategy for reed to positively respond to adverse habitats,which provide a strong theoretical basis and technical reference for searching useful methods for restoration and reconstruction of the degraded ecosystems in desert oasis regions.

关键词： Adaptive strategy Desert oasis Gramineae Nutrients Stoichiometric characteristics

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Electroless plating of carbon nanotubes and their millimeter-wave absorbing properties

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Journal of Beijing institute of Technology 2012年第4期21卷 551-557页

作者：尹艳华付民赵京磊王春芳 The institute of ecosystem Industry School of Chemical Engineering and EnvironmentBeijing Institute of Technology

A method of electroless plating was utilized to deposit Cu, Ni, Co, Ag on the surface of carbon nanotubes （CNTs） respectively, in order to prepare millimeter-wave absorbing materials. Field emission scanning electron microscope （FE-SEM） and energy dispersive spectrometer （EDS） were used to observe morphologies and chemical compositions of the samples respectively. Millime- ter-wave radiometer imaging detection was employed to measure the absorbing properties of the sam- ples. FE-SEM and EDS results demonstrate the effectiveness of successful metal deposition. The re- suits of millimeter-wave radiometer imaging detection reveal that the millimeter-wave absorbing properties of electroless-silver plating are better than other kinds of samples.

关键词： carbon nanotubes electroless plating millimeter wave absorbing properties

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Impact of soil conditions on the physiological characteristics of maize plants in an arid region, Northwest China

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Research in Cold and Arid Regions 2016年第4期8卷 334-342页

作者： LiWen Zhao ZhiBin He WenZhi Zhao Linze Inland River basin Research Station Chinese Ecosystem Network Research Key Laboratory of Ecohydrology of Inland River basin Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences

Overuse of irrigation water to ensure the crop yield of maize plants has caused serious water shortage problems in the middle reach of Heihe River, China. Thus, further research on the physiological characteristics, i.e., photosynthetic rate and leaf transpiration rate, are urgently needed to develop an efficient irrigation management system. In this paper, we selected two common soil textures （sandy loam, sand） and three one-time irrigation volumes （60 mm, 20 mm, 0 mm） in order to analyze the impact of soil conditions on the physiological characteristics of maize plants. Physiological and meteorological factors, soil water content and plant growing parameters were synchronously monitored on Jun. 30, Jul. 25 and Aug. 27 of 2012. The results indicate that sandy loam is better than sand for the growth of maize plants and single irrigation may provide limited influence on the physiological characteristics. Thus, increasing irrigation times and decreasing one-time volume is suggested for an efficient irrigation system.

关键词： photosynthesis leaf transpiration water use efficiency maize plant soil water content

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Cartan-Fubini type extension of holomorphic maps respecting varieties of minimal rational tangents

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Science China Mathematics 2015年第3期58卷 513-518页

作者： HWANG JunMuk Korea institute for Advanced study

A fundamental result in the theory of minimal rational curves on projective manifolds is Cartan- Fubini extension theorem proved by Hwang and Mok, which describes the extensibility of biholomorphisms between connected open subsets of two Fano manifolds of Picard number 1 which preserve varieties of minimal rational tangents （VMRT）, under a mild geometric assumption on the second fundamental forms of VMRT＇s. Hong and Mok have developed Cartan-Fubini extension for non-equidimensional holomorphic immersions from a connected open subset of a Pano manifold of Picard number 1 into a uniruled projective manifold, under the assumptions that the map sends VMRT＇s onto linear sections of VMRT＇s and it satisfies a mild geometric condition formulated in terms of second fundamental forms on VMRT＇s. In the current paper, we give a generalization of Hong and Mok＇s result, under the same condition on second fundamental forms, assuming only that the holomorphic immersions send VMRT＇s to VMRT＇s. Our argument is different from Hong and Mok＇s and is based on the study of natural foliations on the total family of VMRT＇s. This gives a substantially simpler proof than Hong and Mok＇s argument.

关键词： varieties of minimal rational tangents extension of holomorphic maps

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