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Effect of Vegetation Changes on Soil Erosion on the Loess Plateau

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Pedosphere 2006年第4期16卷 420-427页

作者： ZHENG fen-li State Key Laboratory of Soil Erosion and Dryland Farming in Loess Plateau Northwest A＆F University Yangling 712100 （China）.

Vegetation is one of the key factors affecting soil erosion on the Loess Plateau. The effects of vegetation destruction and vegetation restoration on soil erosion were quantified using data from long-term field runoff plots established on the eastern slope of the Ziwuling secondary forest region, China and a field survey. The results showed that before the secondary vegetation restoration period (before about 1866-1872), soil erosion in the Ziwuling region of the Loess Plateau was similar to the current erosion conditions in neighboring regions, where the soil erosion rate now is 8000 to 10000 t km-2 year-1. After the secondary vegetation restoration, soil erosion was very low; influences of rainfall and slope gradient on soil erosion were small; the vegetation effect on soil erosion was predominant; shallow gully and gully erosion ceased; and sediment deposition occurred in shallow gully and gully channels. In modern times when human activities destroyed secondary forests, soil erosion increased markedly, and erosion rates in the deforested lands reached 10000 to 24000 t km-2 year-1, which was 797 to 1682 times greater than those in the forested land prior to deforestation. Rainfall intensity and landform greatly affected the soil erosion process after deforestation. These results showed that accelerated erosion caused by vegetation destruction played a key role in soil degradation and eco-environmental deterioration in deforested regions.

关键词： deforestation Loess Plateau natural vegetation restoration soil erosion

Effects of Accelerated Soil Erosion on Soil Nutrient Loss After Deforestation on the Loess Plateau

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Pedosphere 2005年第6期15卷 707-715页

作者： ZHENG fen-li State Key Laboratory of Soil Erosion and Dryland Farming in Loess Plateau Institute of Soil and Water ConservationChinese Academy of Sciences and Ministry of Water Resources Yangling 712100 （China）

Soil erosion and nutrient losses on newly-deforested lands in the Ziwuling Region on the Loess Plateau of China were monitored to quantitatively evaluate the effects of accelerated soil erosion, caused by deforestation, on organic matter, nitrogen and phosphorus losses. Eight natural runoff plots were established on the loessial hill slopes representing different erosion patterns of dominant erosion processes including sheet, rill and shallow gully (similar to ephemeral gully). Sediment samples were collected after each erosive rainfall event. Results showed that soil nutrients losses increased with an increase of erosion intensity. linear relations between the losses of organic matter, total N, NH4-N, and available P and erosion intensity were found. Nutrient content per unit amount of eroded sediment decreased from the sheet to the shallow gully erosion zones, whereas total nutrient loss increased. Compared with topsoil, nutrients in eroded sediment were enriched, especially available P and NH4-N. The intensity of soil nutrient losses was also closely related to soil erosion intensity and pattern with the most severe soil erosion and nutrient loss occurring in the shallow gully channels on loessial hill slopes. These research findings will help to improve the understanding of the relation between accelerated erosion process after deforestation and soil quality degradation and to design better eco-environmental rehabilitation schemes for the Loess Plateau.

关键词： accelerated soil erosion deforestation erosion intensity Loess Plateau nutrient loss

Regulating FUS liquid-liquid Phase Separation via Specific Metal Recognition

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Chinese Journal of Polymer Science 2022年第9期40卷 1043-1049页

作者： fen li Yiyang lin Yan Qiao Beijing National Laboratory for Molecular Sciences(BNLMS) Laboratory of Polymer Physics and ChemistryCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Chemical Resource Engineering Beijing Laboratory of Biomedical MaterialsBeijing University of Chemical TechnologyBeijing 100029China

liquid-liquid phase separation(LLPS)or biomolecular condensation that leads to formation of membraneless organelles plays a critical role in many biochemical *** study of regulating LLPS is therefore central to the understanding of protein aggregation and disease-relevant *** report a fused in sarcoma protein(FUS)-derived low complexity(LC)sequence that undergoes LLPS in the presence of metal *** LC protein was constructed by fusing a hexhistidine-tag to the N-terminal low complexity domain(the residues 1–165 in QGSY-rich segment)of *** condensation of the intrinsic disordered protein into coacervate droplets was observed in the presence of metal ions that chelate oligohistidine moieties to form protein *** demonstrate the key role of metal ion-histidine coordination in governing LLPS behaviours and the fluidity of biomolecular *** taking advantage of competitive binding using chelators,we show the possibility of regulating dynamic behaviors of disease-relevant protein droplets,and developing a potential approach towards controllable biological encapsulation/release.

关键词： FUS liquid-liquid phase separation Biomolecular condensate Membraneless organelles Protocells Metal coordination

Theoretical Study on Reaction Mechanism of Aluminum-Water System

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Chinese Journal of Chemical Physics 2008年第3期21卷 245-249页

作者： Yun-lan Sun Yan Tian Shu-fen li Department of Chemical Physics University of Science and Technology of China Hefei 230026 China School of Metallurgy and Resources Anhui University of Technology Maanshan 243002 China

A theoretical study on the reaction of aluminum with water in the gas phase was performed using the hybrid density functional B3LYP and QCISD（T） methods with the 6-311＋G（d,p） and the 6-311＋＋G（d,p） basis sets. The results show that there are three possible reaction pathways that involve four isomers, seven transition structures, and two possible products for the reaction of aluminum with water. The two most favorable reaction pathways were found, whose intermediates and products agreed quite well with experimental results. The enthalpy and Gibbs free energy change of the reaction between A1 and H2O at 298 and 2000 K were calculated. Some results are also in good agreement with the previous calculations or experimental results.

关键词： Aluminum Water Reaction mechanism Hybrid density functional theory

Substitution effects on the hydrogen storage behavior of AB2 alloys by first principles

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Frontiers of physics 2011年第2期6卷 214-219页

作者： fen li Ji-jun ZHAO li-xian SUN Key Laboratory of Materials Modification by Laser Ion and Electron Beams （Dalian University of Technology） Ministry of Education Dalian 116024 China College of Advanced Science and Technology Dalian University of Technology Dalian 116024 China Materials and Thermochemistry Laboratory Dalian Institute of Chemical Physics Dalian 1160237 China

The hydrogen storage behavior of the TiCr2 and ZrCr2 alloys substituted with the third components （Zr, V, Fe, Ni） have been studied using first-principles calculations. The change of the hydrogen absorption energies caused by metal doping is arising from the charge transfer among the doped alloys interior. Zr and V atoms devoted abundant electrons, leading to a great enhancement of the H absorption energy, while Fe and Ni atoms always accepted electrons, yielding a remarkable decrease of the H absorption energy. The hydrogen diffusion energy barrier is closely correlated with the geometry effect rather than the electronic structure.

关键词： alloy hydrogen storage doping first-principles

Design and Properties of Fluoroelastomer Composites via Incorporation of MWCNTs with Varied Modification

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Chinese Journal of Polymer Science 2020年第9期38卷 983-992,I0007页

作者： Guang-Yao Yang li-fen Tong Xiao-Bo liu Research Branch of Advanced Functional Materials School of Materials and EnergyUniversity of Electronic Science and Technology of ChinaChengdu 610054China

Multi-walled carbon nanotubes(MWCNTs)modified with silane coupling agent A-1120(MWCNTs-A1120)were *** with the raw MWCNTs,acidified MWCNTs(MWCNTs-COOH),and MWCNTs grafted with EDA(MWCNTs-NH2),MWCNTs-A1120 have the best dispersion in fluoroelastomer at the same doping ***,fluoroelastomer/MWCNTs-A1120 composite has the best mechanical properties with tensile strength of 13.92 MPa and elongation at break of 111.78%.Then,the effects of doping amount of MWCNTs-A1120 on the electrical properties of the composites were *** dielectric constant of the composite increases with the increase of MWCNTs-A1120,and the dielectric loss does not change much at the low doping amount such as 0.5 wt%.When the doping amount of MWCNTs-A1120 is 5 wt%,the dielectric constant and the dielectric loss value are greatly increased,and the volume resistivity is greatly decreased,which proves that the conductive network is formed in the composite,so the filling amount of 5 wt%is the percolation *** tensile deformation of the sample also affects the electrical properties of the *** the tensile deformation increases,the dielectric constant and dielectric loss of the composite *** the composite with 5 wt%MWCNTs-A1120,excessive tensile deformation will destroy the conductive network structure of the composite,so the composite will change from conductive material to dielectric ***,such composite is a good candidate for flexible conductive material or flexible dielectric material used in harsh environments such as high temperatures and various aggressive solvents.

关键词： Modified-MWCNTs Fluoroelastomer nanocomposite Interface compatibility Dielectric properties Volume resistivity

Biosensor Based on TTF@SiO_2 Nanoparticles as Electron Transfer Mediator for the Determination of Glucose

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Chemical Research in Chinese Universities 2006年第4期22卷 474-478页

作者： li Xiao-hua XIAN Yue-zhong MIN Hong li Chen-xin XIE Zong-hong ZHANG fen-fen JIN li-tong Department of Chemistry East China Normal University Shanghai 200062 P. R. China

Tetrathiafulvalene（TTF） was doped in an SiO2 network and the resulting nanocompesite was used as a mediator for the selective detection of glucose. The uniform TTF-doped silica（TIT@SiO2 ） nanoparticles were prepared by the water-in-oil（W/O） microemulsion method, and were characterized by transmission electron microscopy（TEM）. The core-shell structure TTF@ SiO2 could prevent TIT from leaching out into an aqueous solution. Combined with chitosan （CHIT）, which serves as a scaffold for glucose oxidase and nanocomposite immobilization, the GCE/TTF@ SiO2- CHIT-GOx biosensor was developed. Under optimal conditions, the biosensors exhibit a linear range of 1.0 × 10^-5 5 × 10^-3 mol/L with a detection limit down to 5.0 μmol/L（S/N = 3 ）. The excellent selectivity, sensitivity, and stability of the glucose biosensor show its potential for practical applications.

关键词： TTF@ SiO2 nanoparticle Chitosan Glucose Biosensor

Thermodynamic Properties of linear Protein Solutions:an Application to Type Ⅰ Antifreeze Protein Solutions

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Chemical Research in Chinese Universities 2012年第6期28卷 1070-1073页

作者： li li-fen liANG Xi-xia li Qian-zhong Department of Physics lnner Mongolia University Hohhot 010021 P. R. China Department of Basic Curriculum North China Institute of Science and Technology Beijing 101601 P. R. China

A statistical thermodynamic theory of linear protein solutions was proposed with the aid of a lattice model and applied to type Ⅰ antifreeze protein（AFPI） *** numerical results for several AFPI solutions show that the Gibbs function of the solution has a minimum at a certain protein concentration,but the protein chemical potential increases with increasing the *** influences of temperature and protein chain length on the AFPI chemical potential were also *** evaluation for the colligative depression of the freezing point confirms that the antifreeze action should be recognized as *** theoretical deduction for the concentration dependence of the thermal hysteresis activity coincides qualitatively with the previous experimental and theoretical results.

关键词： Antifreeze protein solution Gibbs function Chemical potential Thermal hysteresis

Enhanced dewaterability of waste activated sludge by UV assisted ZVI-PDS oxidation

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Journal of Environmental Sciences 2022年第3期34卷 152-164页

作者： Yanping Zhang Tiantian li Jiayu Tian Huichun Zhang fen li Jiahua Pei School of Civil Engineering and Transportation Hebei University of TechnologyTianjin 300401China Department of Civil and Environmental Engineering Case Western Reserve UniversityClevelandOH 44106USA College of Chemical and Environmental Engineering Harbin University of Science and TechnologyHarbin 150000China

Ultraviolet(UV)assisted zero-valent iron(ZVI)-activated sodium persulfate(PDS)oxidation(UV-ZVI-PDS)was used to treat waste activated sludge(WAS)in this *** dewaterability performance and mechanism of WAS dewatering were *** results showed that UV-ZVI-PDS can obtain better sludge dewatering performance in a wide pH range(2.0-8.0).When the molar ratio of ZVI/PDS was 0.6,UV was 254nm,PDS dosage was 200 mg/g TS(total solid),pH was 6.54,reaction time was 20 min,the CST(capillary suction time)and SRF(specific resistance to filtration)were decreased by 64.0%and 78.2%,*** molar ratio of ZVI/PDS used in this paper is much lower than that of literatures,and the contents of total Fe and Fe^(2+) in sludge supernatant remained at a low level,as 3.7 mg/L and 0.0 mg/*** analysis of extracellular polymeric substances(EPS),scanning electron microscope(SEM)and particle size distribution showed that the EPS could be effectively destroyed by UV-ZVI-PDS,the sludge flocs broken down into smaller particles,cracks and holes appeared,and then the bound water was *** the same time,the highly hydrophilic tightly bound-EPS(TB-EPS)were converted into loosely bound EPS(LB-EPS)and soluble EPS(S-EPS).During sludge pretreated by UV-ZVI-PDS,positively charged ions,such as Fe^(2+),Fe^(3+) and H^(+),produced in the reaction system could reduce the electronegativity of sludge surface,promote sludge particles aggregation,and then enhanced the sludge dewaterability.

关键词： Sludge dewatering Persulfate Zero-valent iron UV Extracellular polymeric substances