不同尺度转换方式对土地利用格局模拟的影响效应研究

以张家界市永定区为研究对象,根据2005年土地利用现状图和数字高程模型数据源得到的土地利用、地形、河流以及道路等空间数据,在不同的尺度聚合方法下构建了多种尺度上的土地利用格局模拟模型,以试图探讨不同尺度转换方式对土地利用格局模拟的影响。研究结果显示:① 在空间尺度逐渐增大过程中,中心值原则（RCC）下,模型的拟合优度（ROC值）变化相对较大,表现出很强的随机性,在400 m×400 m和700 m×700 m的尺度时,ROC值出现明显的波动;② 面积最大原则（RMA）和优化组合方法（OIM）下,随着聚合尺度的升高,模型的拟合优度值变化相对较为平缓,且ROC值逐渐增大的趋势比较明显;③ 比较RCC、RMA和OIM三种方法,优化组合方法（OIM）具有更高的拟合优度,在各种聚合尺度上,土地利用类型的ROC值均得到了明显的提高（耕地、林地和建设用地的平均ROC值分别提高到0.767,0.785,0.895）;④ 各种尺度转换方法下,在1 700 m×1 700 m尺度时各种地类格局的拟合均出现ROC的峰值,可以认为1 700 m是永定区土地利用格局的最佳模拟尺度。研究结果对区域进行土地利用的规划、制定相应的土地开发与利用政策等也具有一定的参考意义。     

坡面人工植物群落修复对水土流失及控磷的影响

研究地位于巢湖市夏阁镇大庙村,巢湖流域富磷地区小柘皋河上游,该区域开采严重,形成大量的裸露区域,控制该区的水土流失、减少磷流失对巢湖的富营养化具有重要意义.在自然降雨条件下,在坡度为30.的坡地建立15个径流小区,以裸地为对照,研究了5种不同的建植模式:D1(裸地)、D2(狗牙根群落覆盖区)、D3(胡枝子+马棘群落覆盖...     

低碳减排对促进绿色农业农机的贡献和意义

近年来,由于全球经济突飞发展,碳过量排放引起温室效应,造成全球气候变暖,保护环境已成为时代主旋律,为此,沛县农机部门把握时代机遇,积极推进低碳减排,促进绿色农机化作业。     

根结线虫卵寄生真菌蜡蚧菌(Lecanicillium lecanii)产生的几丁质酶活性

卵寄生真菌产生的几丁质酶在卵孵化和寄生过程中发挥重要的作用,也是评价寄生线虫真菌生物防治潜力重要的生化指标之一。利用NAG法和pNP法分别测定蜡蚧菌(Lecanicillium lecanii)CFCC84957和CFCC80920菌系的几丁质降解酶系和外切酶活性,CFCC84957菌系接种4～6d含有0.2%胶体几丁质的培养滤液后,几丁质降解酶系到达活性高峰期,而CFCC80920菌系的培养滤液未检测到几丁质降解酶系。2个菌系的培养滤液从第2d开始均能检测到几丁质外切酶活性,CFCC84957和CFCC80920活性出现的最高峰分别在第12d和6d,但是CF-CC84957的活性值约是CFCC80920的4倍(分别为0.51μmol·h-1·ml-1、0.12μmol·h-1·ml-1)。含有0.01%糖基化几丁质的几丁质酶活性电泳检测到1条分子量为48.2kD的蛋白质谱带。     

Effect of Inoculation Rhizobium and Response of Soybean-Rhizobium System to Insoluble Phosphate

In order to produce efficiently symbiotic system in acid soils which could be used for the recovery of insoluble phosphate soil and improvement of the fertility,etc.,host range of Rhizobium was isolated from the root nodules of wild and cultivated soybean varieties growing in south China,evaluated the effects of Rhizobium on enhance nitrogen fixing activities,phosphorus(P),nitrogen (N)uptakes,growth and yield of soybean under pot and field conditions.The results showed that combined Rhizobium inoculation was more effective than individual Rhizobium inoculation. The combined Rhizobium of CW54 strains had the highest effect, nodule number, nodule weight and nodule nitrogenase activity were markedly stimulated as compared to those of the control U110, respectively. The nitrogen contents in the plants treated with CW54 strains were significantly increased by 43.2% as compared to those of the control U110 in Al-P soil, but statistical significance was not observed in Fe-P soil. By contrast, inoculation with CW54 significantly enhanced phosphorus uptake of plant in Fe-P soil than that in Al-P soil. The effects of inoculation of CW54 strains in a field condition were similar to those of in a pot condition. The total biomass and yield in the plants treated with CW54 strains were significantly increased by 86.4% and 51.4% as compared to those of the control at the time of soybean podding in a field condition, respectively.These results suggested that inoculation Rhizobium was beneficial for soybean nutrient uptake,growth and yield under insoluble phosphate soil conditions.     

Mapping and Comparative Analysis of QTL for Rice Plant Height Based on Different Sample Sizes within a Single Line in a RIL Population

To clarify the most appropriate sample size for obtaining phenotypic data for a single line, we investigated the main-effect QTL (M-QTL) of a quantitative trait plant height (ph) in a recombinant inbred line (RIL) population of rice (derived from the cross between Xieqingzao B and Zhonghui 9308) using five individual plants in 2006 and 2009. Twenty-six ph phenotypic datasets from the completely random combinations of 2, 3, 4, and 5 plants in a single line, and five ph phenotypic datasets from five individual plants were used to detect the QTLs. Fifteen M-QTLs were detected by 1 to 31 datasets. Of these, qph7a was detected repeatedly by all the 31 ph datasets in 2006 and explained 11.67% to 23.93% of phenotypic variation; qph3 was detected repeatedly by all the 31 datasets and explained 5.21% to 7.93% and 11.51% to 24.46% of phenotypic variance in 2006 and 2009, respectively. The results indicate that the M-QTL for a quantitative trait could be detected repeatedly by the phenotypic values from 5 individual plants and 26 sets of completely random combinations of phenotypic data within a single line in an RIL population under different environments. The sample size for a single line of the RIL population did not affect the efficiency for identification of stably expressed M-QTLs.     

水砂石破坏混凝土坝力学机理

从水砂石宏观力学和微观力学的作用效果出发,定性地探讨了水砂石破坏混凝土坝的力学机理,得出了混凝土力学性能变化的趋势,并在此基础上提供了一些展望与看法。     

Axisymmetrical deformation of prestressed circularmembrane under uniformly distributed loads

With establishing the fundamental equation of prestressed circular membrane under Fppl von Kármán membrane theory, Hencky transform is extended and the general solution of axisymmetrical deformation of prestressed circular membrane under uniformly distributed loads is obtained. The central deflection, the radial and circumferential stresses of the membrane are given in the form of power series. And it is found that the solution approaches to the results from Hencky theory when the prestressing is far less than the loads; and the solution approaches to the results based on linear theory when the prestressing is far greater than the loads.     

Bamboo simulation based on fractal algorithm

Fractal theories are quite popular in modeling and simulation of objects with irregular shapes. The combination of fractal theories and virtual reality technologies may be used to generate the realistic and complex nature objects. Plants simulation is one of the most important fields in computer graphics. The simulation algorithms of Bamboo are discussed. The conventional L-system modeling approach is improved based on the single-axis characteristics of Bamboo, and the relevant method, e.g. the displacement mapping technique used in Bamboo internodes modeling and rendering is discussed as well. Moreover, based on the basic idea of particle system, an improved simulation approach for distribution pattern of Bamboo is presented.This improved simulation algorithm can make the random distribution of particles break the rules of rectangular shape. Simulation results show that the proposed methods can simulate realistic Bamboo forms and distribution patterns in the nature.     

Study on NO2 gas sensing characteristics of In doped ZnO thin films prepared by RF magnetron sputtering

In doped ZnO thin films were prepared on glass substrate by RF magnetron sputtering. The result of XRD and AFM shows that the films are polycrystalline with high c axis orientation. The study of gas sensing reveals that the films are sensitive to NO2 and the best sensibility occurs at 273 ℃; the sensibility is concerned with the concentration of NO2 and the film thickness. The ZnO∶In films are more sensitive to the NO2 gas with higher concentration of NO2 and thinner films have a better sensitivity. Exposed to 2×10-5 NO2 at 273 ℃, the 90nm thick film has a sensibility of 16, indicating that ZnO∶In films can be used to measure NO2 with a low concentration.