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Decomposition of Phragmites australis rhizomes in artificial land-water transitional zones （ALWTZs） and management implications

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Frontiers of Earth Science 2015年第3期9卷 555-566页

作者： Zhen HAN Baoshan CUI yongtao zhang State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing 100875 China

Rhizomes are essential organs for growth and expansion of Phragmites australis. They function as an important source of organic matter and as a nutrient source, especially in the artificial land-water transitional zones （ALWTZs） of shallow lakes. In this study, decomposition experiments on 1- to 6-year-old R australis rhizomes were conducted in the ALWTZ of Lake Baiyangdian to evaluate the contribution of the rhizomes to organic matter accumulation and nutrient release. Mass loss and changes in nutrient content were measured after 3, 7, 15, 30, 60, 90, 120, and 180 days. The decomposition process was modeled with a composite exponential model. The Pearson correlation analysis was used to analyze the relationships between mass loss and litter quality factors. A multiple stepwise regression model was utilized to determine the dominant factors that affect mass loss. Results showed that the decomposition rates in water were significantly higher than those in soil for 1- to 6-year-old rhizomes. However, the sequence of decomposition rates was identical in both water and soil. Significant relationships between mass loss and litter quality factors were observed at a later stage, and P-related factors proved to have a more significant impact than N-related factors on mass loss. According to multiple stepwise models, the C/P ratio was found to be the dominant factor affecting the mass loss in water, and the C/N and C/P ratios were the main factors affecting the mass loss in soil. The combined effects of harvesting, ditch broadening, and control of water depth should be considered for lake administrators.

关键词： Phragmites australis rhizomes mass loss,decomposition rates nutrient contents Pearson correlationanalysis Artificial Land-Water Transitional Zone(ALWTZ)

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Solution-processed rare-earth thulium oxide with high permittivity for low-voltage transistor and inverters applications

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Journal of Rare Earths 2024年第8期42卷 1604-1609,I0007页

作者： Daiming Liu Fei Wang yongtao zhang Ya'nan Ding Shandong Engineering Laboratory for Preparation and Application of High-performance Carbon-Materials College of Electromechanical EngineeringQingdao University of Science&TechnologyQingdao266061China College of Electronic and Information Engineering Shandong University of Science and TechnologyQingdao266590China

The use of high-permittivity(high-k) thin films as gate dielectrics is essential in the development of lowpower electronics,In this work,rare-earth thulium oxide(Tm_(2)O_(3)) thin films were prepared by a facile solution process and annealed at various temperatures from 400 to 700℃.The evolution of the physical and dielectric properties of Tm_(2)O_(3) thin film with annealing temperature was *** is demonstrated that the Tm_(2)O_(3) thin film annealed at 600℃ exhibits the optimal performance,including a low leakage current of 3×10^(-10) A/cm^(2),a large areal capacitance of 250 nF/cm^(2) at 100 Hz,and a high permittivity value of *** Tm_(2)O_(3) thin film as a gate insulator was integrated into the thin film transistor(TFT) employing In_(2)O_(3)-based semiconducting *** In_(2)O_(3) TFT with 600℃-annealed Tm_(2)O_(3) dielectric exhibits the superior perfo rmance,with a high I_(on)/I_(off) of 1.65×10^(7),a small subthre shold swing(SS) value of 0.2 V/dec,a V_(TH) of+1.8 V,and a mobility of 1.68 cm^(2)/(V·s).Furthermore,an inverter constructed by connecting the TFT with a resistor exhibits full-swing *** work provides a facile and appealing method for preparing the high-k Tm_(2)O_(3) thin films as alternative gate dielectrics with the potential for use in low-power electronics and logic circuit applications.

关键词： Rare earths Tm_(2)O_(3) Dielectric Transistor Inverter

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CFD Investigations of Interaction Between Freak Wave and Bottom-Mounted Vertical Cylinder

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Journal of Shanghai Jiaotong university(Science) 2024年第5期29卷 809-816页

作者： GAO Ningbo zhang yongtao zhang Hong CCCC Second Harbor Engineering Co. Ltd.Wuhan430040China Key Laboratory of Large-Span Bridge Construction Technology Wuhan430040China Research and Development Center of Transport Industry of Intelligent Manufacturing Technologies of Transport Infrastructure Wuhan430040China CCCC Highway Bridges National Engineering Research Centre Co. Ltd.Beijing100088China

We studied the interactions between freak wave and bottom-mounted vertical *** freak wave is generated through linear superposition method which satisfies the definition that the wave height is at least two times the significant wave height.A numerical wave tank is developed based on FLUENT software in which the finite volume method is used for the spatial *** sensitivity is conducted in 2D model,and then the freak wave is simulated in 3D *** freak wave loads on the vertical cylinder are calculated and compared with the results obtained through Morison *** numerical results present larger peak and shallower trough compared with the prediction of Morison ***,the free surface wave elevation within a radius distance around the vertical cylinder is *** lowest wave run-up around vertical cylinder caused by freak wave is about 55%of the highest wave run-up,and the direction is about 45°of the wave propagation.

关键词： Navier-Stokes equations freak wave wave run-up wave force

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Spatial Distribution and Environmental Determinants of Denitrification Enzyme Activity in Reed-Dominated Raised Fields

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Chinese Geographical Science 2015年第4期25卷 438-450页

作者： LAN Yan CUI Baoshan HAN Zhen LI Xia LI Fengju zhang yongtao School of Environment State Key Joint Laboratory of Environmental Simulation and Pollution Control Beijing Normal University

Denitrification is an important process of nitrogen removal in lake ***,the importance of denitrification across the entire soil-depth gradients including subsurface layers remains poorly *** study aims to determine the spatial pattern of soil denitrification enzyme activity(DEA) and its environmental determinants across the entire soil depth gradients in the raised fields in Baiyang Lake,North *** two different zones of the raised fields(i.e.,water boundary *** body of the raised fields),the soil samples from 1.0 m to 1.1 m depth were collected,and the DEA and following environmental determinants were quantified:soil moisture,p H,total nitrogen(TN),ammonia nitrogen(NH4+-N),nitrate nitrogen(NO3–-N),total organic carbon(TOC),and rhizome biomass of Phragmites *** results showed that the soil DEA and environmental factors had a striking zonal distribution across the entire soil depth *** soil DEA reached two peak values in the upper and middle soil layers,indicating that denitrification are important in both topsoil and subsurface of the raised *** correlation analysis showed that the DEA is negatively correlated with the soil depth(p < 0.05).However,this phenomenon did not occur in the distance to the water edge,except in the upper layers(from 0.2 m to 0.7 m) of the boundary zone of the raised *** the main body of the raised fields,the DEA level remained high;however,it showed no significant relationship with the distance to the water *** linear regression analysis showed significant positive correlation of the DEA with the soil TN,NO3–-N,NH4+-N,and TOC;whereas it showed negative correlation with soil p *** significant correlations with soil moisture and temperature were observed.A positive correlation was also found between the DEA and rhizome biomass of ***.

关键词： denitrification enzyme activity(DEA) nitrate removal raised fields Baiyang Lake rhizomes

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Bucket Group Effect of the Composite Multi-bucket Structure

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Journal of Marine Science and Application 2014年第1期13卷 62-66页

作者： Shucheng Jin Yanhua Yang yongtao zhang Technology Center The Second Harbour Engineering Co.Ltd.

As a novel type of foundation in beach and shallow sea, the bucket structure is especially suitable for complex conditions such as soft clay ground and the worse types of sea environments. In this paper, the bearing capacity of a multi-bucket structure is studied by experiments with a single bucket and four-bucket foundation in a saturated sand layer. Based on the experimental data and numerical analysis results, the bearing capacity behavior and the bucket group effect are compared and analyzed. Furthermore, some influential factors, such as the soil type, the ratio of length to diameter L/D, the ratio of the bucket spacing to the bucket diameter S/D, and the bucket number are introduced and their effects on the multi-bucket structural capacity are investigated. The vertical static capacity adjustment factor is introduced to evaluate the bucket group effects of the multi-bucket foundation.

关键词： bucket group effect composite multi-bucket structure bearing capacity displacement control method vertical staticcapacity adjustment factor

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Specific hydrolysis of DNA by Ce^(4+)-ODN hybrid

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Science China Chemistry 2004年第1期47卷 75-79页

作者： SHEN Hebai ZHOU Wenjun YANG yongtao zhang Feng College of Life and Environment Science Shanghai Normal University Shanghai 200234 China College of Life and Environment Science Shanghai Normal University Shanghai 200234 China College of Life and Environment Science Shanghai Normal University Shanghai 200234 China College of Life and Environment Science Shanghai Normal University Shanghai 200234 China

The cerium complex bound to the derivative of oligoDNA has been synthesized successfully that can hydrolyze DNA with sequence-specificity. The synthesized derivative of oligoDNA, 5′-EDTA-P-10 mers ODN, was demonstrated by HPLC. The fluorescence spectrum of Tb3+ was detected after its interaction with the hybrid of 10-mers ODN and 26-mers ODN and the results show that the artificial endo-enzyme can recognize and combine firmly with the substrate DNA. The electrophorogram shows that the cerium-oligoDNA hybrid can specifically hydrolyze its substrate DNA and the cleavage site of this hydrolysis reaction is also discussed. This artificial nuclease can be widely used in molecular biology and genetic engineering as one kind of endo-enzyme.

关键词： oligomer DNA, Ce4+ complex, fluorescence spectrum, HPLC, hydrolyze DNA specifically.

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Analysis of χ Phase Precipitation in Aged 2205 Duplex Stainless Steel

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Journal of Wuhan University of Technology(Materials Science) 2015年第3期30卷 591-595页

作者：刘和平 SUN Hu'er LIU Bin LI Dazhao SUN Fenger zhang yongtao School of Materials Science and Engineering North University of China School of Machinery Shanghai Dian Ji University

Analysis ofZ phase precipitation in 2205 duplex stainless steel aged at 700 and 750 ~C has been investigated systematically. The experimental results showed that X phase forms prior to the precipitation of δ phase and disappears once tr phase starts to precipitate. This phenomenon indicates that a phase nucleated and consumed the Z phase. The δ phase nucleated mairdy at ferrite/austenite interface and grew inwards into the ferrite phase. The morphology of a phase reveals a coral-like structure at the temperature of 700 ℃ for 120 min followed by quenching in water. The decomposition of ferrite occurs via the following eutectoid reaction： F---＊o＇＋y2. The selected area diffraction pattern of zone axes is[3 1 3-][3 1 3], indicating a characteristic orientation relationship between X phase and δ-ferrite.

关键词： duplex stainless steel X phase tr phase microstructure analysis

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Hot Deformation Behavior of Low Carbon Steel during Compression at Elevated Temperature

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Journal of Wuhan University of Technology(Materials Science) 2014年第3期29卷 601-605页

作者：刘和平 LIU Bin LI Dazhao SUN Hu'er SUN Feng'er JIN Xuejun zhang yongtao School of Materials Science and Engineering North University of China School of Materials Science and Engineering Shanghai Jiao Tong University School of Machinery Shanghai DianJi University

Hot compression tests of low carbon steel were carried out on Gleeble-3500 system in the temperature range from 750 to 900 ℃ and in the strain rate range from 0.001 to 1.0 s^-1, and the associated microstructural evolution was studied by observations with a metallographic microscope. The results show that the stress-strain curves exhibit a peak stress at critical strain, after which the flow stresses *** monotonically until reaching high strains, showing a dynamic flow softening. The peak stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by the Zener-Hollomon parameter Z in the hyperbolic sine equation. The flow stress increases with increasing strain rate and decreasing deforming temperature. The flow stress can be described by constitutive equation in hyperbolic sine function and can also be described by a Zener-Hollomon parameter Z. With increasing deformation temperature and deereasing strain rate, the grain size as well as the volume fraction of the reerystaUized grains increase. The safe region for hot working of the alloy has been determined according to the processing map and microstructure at the true strain of 0.5, which is the deformation temperature of 840-940 ℃ and the strain rate of 0.001-1.0 s^-1.

关键词： hot deformation dynamic recrystallization constitutive equation processing map

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Same impact momentum causes different degrees of spinal cord injury

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Chinese Science Bulletin 2014年第32期59卷 4298-4303页

作者： Le Ji Xiaoqian Dang Binshang Lan Qichun Song Dapeng Duan Zhe Ji yongtao zhang Lisong Heng Department of Orthopedic Surgery The Second Affiliated Hospital School of Medicine Xi’an Jiaotong University Department of Orthopedic Surgery Shaanxi Provincial People’s Hospital Department of Orthopedic Surgery Xi’an Honghui Hospital

The weight-drop impact is widely used in making animal model of spinal cord injury(SCI).But there has not yet been an appropriate unit for the quantification of the *** this study,we compared the degrees of the spinal cord injury caused by weight-drop impact with the same momentum but different combinations of drop weight and drop height,in order to test whether‘‘momentum’’is capable of being the unit for the quantification of weightdrop *** adult rats were randomly allocated to three groups and were injured with 5 g–10 cm(group A),10 g–2.5 cm(group B)and 15 g–1.11 cm(group C)impacts with the same momentum to the spinal cord,***-field locomotor function was evaluated using the Basso–Beattie–Bresnahan(BBB)locomotor rating *** percentage of spared tissue area(STA)at the epicenter,and 500,1000 and 1500 lm from the epicenter was calculated using serial sections stained by hematoxylin and *** a result,the behavioral recovery(BBB scores)and the STA percentage were similar in group B and group ***,the BBB score in group A was significantly lower than that in groups B and C at the same time point post *** STA percentage was significantly less and the lesion/cavity length was significantlygreater in group A than in groups B and *** suggested that the 5 g–10 cm weight-drop impact,compared with the other two impacts with different weights and heights,caused a greater damage of the spinal cord when the momentum was the ***,these impacts with the same momentum but different weights and drop heights cause different degrees of spinal cord *** alone is inadequate to be the unit for the qualification of weightdrop impact and to be used to predict the extent of injury.

关键词：脊髓损伤运动功能 HE染色 STA 动物模型成年大鼠连续切片跌落高度

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LAND EVALUATION AND RATIONAL STRUCTURE OF LAND-USE IN DESERT STEPPE AREA IN NINGXIA HUI AUTONOMOUS REGION

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干旱区资源与环境 1993年第Z1期7卷 176-178页

作者： zhang yongtao Shen Yuancun Tnstitute of Geography, Chinese Academy of Sciences, Beijing, 100101

Located in the middle and north part of Ningxia Hui Autonomous Region, the desertsteppe area includes the whole of Shizuishan, Huinong, Pingluo, Taole, Helan, Yingchuan,Yongning, Lingwu, Qingtongxia, Wuzhong, Zhongning, and Zhongwei counties and thenorth part of Yanchi, Tongxin counties. This region has an area of 32020 km^2. The popula-

关键词： Desert Steppe Land Resources Evaluation Land Use Structure

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