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Preliminary Response of Soil Fauna to Simulated N Deposition in Three Typical Subtropical Forests

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Pedosphere 2006年第5期16卷 596-601页

作者： XU Guo-Liang MO Jiang-Ming ZHOU Guo-Yi fu Sheng-Lei Institute of Ecology South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 （China） Graduate School of the chinese academy of sciences Beijing 100039 （China）

A field-scale experiment arranged in a complete randomized block design with three N addition treatments including a control (no addition of N), a low N (5 g m-2 year-1), and a medium N (10 g m-2 year-1) was performed in each of the three typical forests, a pine (Pinus massoniana Lamb.) forest (PF), a pine-broadleaf mixed forest (MF) and a mature monsoon evergreen broadleaf forest (MEBF), of the Dinghushan Biosphere Reserve in subtropical china to study the response of soil fauna community to additions of N. Higher NH4+ and NO3- concentrations and a lower soil pH occurred in the medium N treatment of MEBF, whereas the NO3- concentration was the lowest in PF after the additions of N. The response of the density, group abundance and diversity index of soil fauna to addition of N varied with the forest type, and all these variables decreased with increasing N under MEBF but the trend was opposite under PF. The N treatments had no significant effects on these variables under MF. Compared with the control plots, the medium N treatment had significant negative effect on soil fauna under MEBF. The group abundance of soil fauna increased significantly with additions of higher N rates under PF. These results suggested that the response of soil fauna to N deposition varied with the forest type and N deposition rate, and soil N status is one of the important factors affecting the response of soil fauna to N deposition.

关键词： Dinghushan Biosphere Reserve N deposition soil fauna subtropical china

First-principles calculation on the electronic structures, phonon dynamics, and electrical conductivities of Pb_(10)(PO_(4))_(6O) and Pb_(9)Cu(PO_(4))_(6O) compounds

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Journal of Materials Science & Technology 2024年第6期173卷 218-224页

作者： L.Y.Hao E.G.fu State Key Laboratory of Nuclear physics and Technology Department of Technical PhysicsSchool of PhysicsPeking UniversityBeijing 100871China

Superconducting materials with high critical temperature have the potential to revolutionize many fields,including military,electronic communications,and power ***,scientists around the world have been tirelessly working with the ultimate goal of achieving high-temperature *** 2023,a preprint by Lee et *** South Korea claimed the discovery of ultra-high-temperature superconductivity with a critical temperature of up to 423 K in Cu-doped lead-apatite(LK-99)(arXiv:2307.12008,arXiv:2307.12037),which caused a worldwide sensation and ***,the electronic structures,phonon dynamics,and electrical conductivities of LK-99 and its parent compound lead-apatite have been calculated using first-principles *** results show that the lead-apatite compound and the LK-99 compound are insulator and half-metal *** flat band characteristic is consistent with previous *** electrical conductivity of the LK-99 compound shows two extreme points,and the electrical conductivity along the C-axis increases significantly after 400 *** phonon dispersion spectra of the compounds were investigated,demonstrating their dynamic instability.

关键词： Superconductivity LK-99 Lead-apatite First-principles calculation

Availability analysis of private cloud safety computer platform based on the Markov process

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Transportation Safety and Environment 2024年第1期6卷 103-108页

作者： Limin fu Jiakun Wen Southwest Jiaotong University The School of Information Science&TechnologyChengduSichuan 610097China CRSC Research&Design Institute Group Co. LtdBeijing 100070China

To ensure the correctness of train control system design and development,the ways of simulation,test and formalization were *** to the safe critical attribute of train control system,the characters related to system safety were propounded such as real time,hybrid,distribution(concurrence)and reactivity,and the specific formal methods associated with every character were introduced in *** analysis and classification of the methods were done based on their mathematical basis and applications,and their advantages and disadvantages were *** result indicates that every method has determinate limitations,which is determined by the essences of model checking and theory *** is pointed out that the presentation of new method,the expansion of existing methods and the integration of many methods will be the development trend of formalization in train control system.

关键词： safety computer Markov process cloud computing availability analysis

Effects of acid deposition on forests in south china

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Journal of Environmental sciences 1998年第4期10卷 122-126页

作者： Feng Zong wei, Tao fu lu Research Center for Eco-Environmental sciences, chinese academy of sciences, beijing 100085, china

Acid deposition has caused serious damage to the forests of china. In this paper, the quantification theory I is used to calculate the forest volume loss caused by acid disposition in seven provinces of south china. The results showed that contribution rates of acid deposition to forest volume loss in seven provinces of south china vary from 24 5% to 37 91%; the volume loss rates range from 7% to 20%. Total volume losses per year are 1 0145×10 6 m 3, of which Zhejiang Province is the greatest, totalling 3 841×10 5 m 3, while Anhui Province is the least, amounting to 1 59×10 4 m 3.

关键词： acid deposition damage forest volume loss. 

Gyroid Triply Periodic Minimal Surface Lattice Structure Enables Improved Superelasticity of CuAlMn Shape Memory Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 1047-1065页

作者： Mengwei Wu Chunmei Ma Ruiping Liu Huadong fu Department of Materials Science and Engineering China University of Mining and Technology(Beijing)Beijing100083China Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing100083China

Improving the shape memory effect and superelasticity of Cu-based shape memory alloys(SMAs)has always been a research hotspot in many *** work systematically investigates the effects of Gyroid triply periodic minimal surface(TPMS)lattice structures with different unit sizes and volume fractions on the manufacturing viability,compressive mechanical response,superelasticity and heating recovery properties of CuAlMn *** results show that the increased specific surface area of the lattice structure leads to increased powder adhesion,making the manufacturability proportional to the unit size and volume *** compressive response of the CuAlMn SMAs Gyroid TPMS lattice structure is negatively correlated with the unit size and positively correlated with the volume *** superelastic recovery of all CuAlMn SMAs with Gyroid TPMS lattice structures is within 5%when the cyclic cumulative strain is set to be 10%.The lattice structure shows the maximum superelasticity when the unit size is 3.00 mm and the volume fraction is 12%,and after heating recovery,the total recovery strain increases as the volume fraction *** study introduces a new strategy to enhance the superelastic properties and expand the applications of CuAlMn SMAs in soft robotics,medical equipment,aerospace and other fields.

关键词： Shape memory alloys Superelasticity Gyroid triply periodic minimal surface(TPMS)lattice structure Selective laser melting(SLM)

STUDY ON THE SECOND HARMONIC GENERATION OF SOME LANTHANIDE(Ⅲ) COORDINATION COMPOUNDS

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chinese Chemical Letters 1992年第2期3卷 135-136页

作者： Jia fu WANG~*, Meng Hui CAI, Cheng YE, Zhi Ming FENG Institute of Chemistry, chinese academy of sciences, beijing 100080

The measurements of second harmonic generation efficiencies of some coordination compounds of lanthanide(Ⅲ) carboxylates and β-diketonates have been reported. The results show thatmost of lanthanide cinnamate have S... 详细信息

关键词： SHG than COORDINATION COMPOUNDS STUDY ON THE SECOND HARMONIC GENERATION OF SOME LANTHANIDE

Fractal properties of patch perimeters in a disturbed montane landscape,beijing,china

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Journal of Environmental sciences 1999年第2期11卷 68-72页

作者： Ma Ke ming, fu Bo jie Research Center for Eco Environmental sciences, chinese academy of sciences, beijing 100085, china

The forest landscape has been highly fragmented in Donglingshan montane region, beijing, china, where the folding degree of patch perimeters considerately influenced the spatial distribution of biological diversity, therefore the quantitative description to it is very helpful to conservation biology studies. The fractal dimensions of landscape patch perimeters of this region were estimated and compared. The results showed that fractal dimensions of all the landscape types were between 1.00 and 1.58. The fractal dimensions of natural vegetation types were higher than that of artificial vegetation type. Where forests (1 21) and shrubs (1.24) are near to farmland (1.12), so they were both highly disturbed by human activities regarding the smallest mean patch areas. But the grassland (1.58) had the largest mean patch area, its disturbance intensity was the lowest in this region. The fractal dimension of the overall landscape was 1.24, which was near to those of forests and shrubs, and obviously different from those of farmland and grassland. The fractal dimension of the overall landscape was 1.13 in small scales, and that was 1.65 in large scales. Which means that a large number of small area patches had regular perimeters, their fragment degrees were higher; whereas the large area patches had folding perimeters, their fragment degrees were lower, they had smaller patch numbers, however occupied most of the landscape area. Large areas and highly folded perimeters were the main property of the landscape patch in Donglingshan montane region.

关键词： beijing Dongling montane region landscape fragmentation patch perimeter fractal dimension.

Nonlinear uncertainty impact of geometric variations on aerodynamic performance of low-pressure turbine blades with ultra-high loading under extreme operational conditions

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chinese Journal of Aeronautics 2024年第5期37卷 281-300页

作者： Xiaojing WANG Zhengping ZOU Chao fu Pengcheng DU School of Energy and Power Engineering Beihang UniversityBeijing 100191China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 100191China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

Uncertainty impact of random geometric variations on the aerodynamic performance of low-pressure turbine blades is considerable,which is further amplified by the current ultra-high-lift design trend for weight ***,this uncertainty impact on ultra-highly loaded blades under extreme operational conditions near the margins with potential large-scale open separation is focused on in this *** is demonstrated that this impact is significant,unfavourable,and nonlinear,which is clearly severer under extreme *** addition to the overall attenuation and notable scattering of specific performance,the operational margins with open separation are also notably scattered with great risk of significant *** scattering and nonlinearity are dominated by the variations in leading-edge *** thinning of leading edge triggers local transition,enhancing downstream friction and reducing resistance to open separation,which is further exacerbated by operational ***,the opposite thickening yields less benefit,implying *** unfavourable impact highlights the need for robust aerodynamic design,where both a safer operational condition and a more robust blade are indispensable,i.e.,a compromise among performance,weight,and *** the necessary limitation of loading levels,a mid-loaded design is recommended to reduce adverse pressure gradients in both the leading edge and rear region of the suction side,which helps to decrease the susceptibility of the transition and open separation to random *** improvements can also be achieved by appropriately thickening the leading edge.

关键词： Ultra-highly loaded turbine blade Geometric variations Uncertainty analysis Operational margins Robust aerodynamic design Nonlinearity

Analytical computation of magnetic field in coil-dominated superconducting quadrupole magnets based on racetrack coils

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Nuclear Science and Techniques 2024年第4期35卷 119-135页

作者： Chuang Shen Ying-Shun Zhu fu-San Chen china Spallation Neutron Source Institute of High Energy PhysicsChinese Academy of Sciences1 Zhongziyuan RoadDongguan 523000China Institute of High Energy physics Chinese Academy of Sciences19B Yuquan RoadBeijing 100049China University of chinese academy of sciences Beijing 100049China

Currently,three types of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and ***,all three coil configurations have complex spatial geometries,which make magnet manufacturing and strain-sensitive superconductor applications *** with the three existing quadrupole coils,the racetrack quadrupole coil has a simple shape and manufacturing process,but there have been few theoretical *** this paper,the two-dimensional and three-dimensional analytical expressions for the magnetic field in coil-dominated racetrack superconducting quadrupole magnets are *** analytical expressions of the field harmonics and gradient are fully resolved and depend only on the geometric parameters of the coil and current ***,a genetic algorithm is applied to obtain a solution for the coil geometry parameters with field harmonics on the order of 10^(-4).Finally,considering the practical engineering needs of the accelerator interaction region,electromagnetic design examples of racetrack quadrupole magnets with high gradients,large apertures,and small apertures are described,and the application prospects of racetrack quadrupole coils are analyzed.

关键词： Superconducting quadrupole magnet Racetrack coil Multipole field Genetic algorithm Magnetic design