Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matter...Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matters were analyzed. The results showed that contents of total N, total P and organic matters were generally decreasing with the increase of distance from sample locations to the river channel, and contents of the three items were generally higher in the upper soil layer than that in the lower soil layer. The content variations displayed how flooding functions influenced nutrient matter content variations in floodplain soils since the flood inundation frequencies of the sample locations varied. The correlation analysis displayed that there were remarkable relativities between total N, total P and organic matters within definite spatial distance from the Huolin River channel.展开更多
Accurate reconstruction from a reduced data set is highly essential for computed tomography in fast and/or low dose imaging applications. Conventional total variation（TV）-based algorithms apply the L1 norm-based pen...Accurate reconstruction from a reduced data set is highly essential for computed tomography in fast and/or low dose imaging applications. Conventional total variation（TV）-based algorithms apply the L1 norm-based penalties, which are not as efficient as Lp（0〈p〈1） quasi-norm-based penalties. TV with a p-th power-based norm can serve as a feasible alternative of the conventional TV, which is referred to as total p-variation（TpV）. This paper proposes a TpV-based reconstruction model and develops an efficient algorithm. The total p-variation and Kullback-Leibler（KL） data divergence, which has better noise suppression capability compared with the often-used quadratic term, are combined to build the reconstruction model. The proposed algorithm is derived by the alternating direction method（ADM） which offers a stable, efficient, and easily coded implementation. We apply the proposed method in the reconstructions from very few views of projections（7 views evenly acquired within 180°）. The images reconstructed by the new method show clearer edges and higher numerical accuracy than the conventional TV method. Both the simulations and real CT data experiments indicate that the proposed method may be promising for practical applications.展开更多
[Objective]The aim was to reveal the spatial distribution characteristics of total nutrients in soil and provide a theoretical basis for farmland management and improvement of crop yield. [Method]GIS technique was use...[Objective]The aim was to reveal the spatial distribution characteristics of total nutrients in soil and provide a theoretical basis for farmland management and improvement of crop yield. [Method]GIS technique was used to analyze the spatial distribution characteristics of total C,total N,total P and total K for different soil layers in Liaoning Province. [Result]The results showed that the content of total C,total N,total P decrease from east to west,but the content of total K was high in north district of Liaoning Province. The content of total C,total N,total P and total K was higher in soil surface （0-20 cm） than the lower （20-40 cm）. Total K varied less with soil depth,and its mean content was respectively 17.64 g/kg and 17.08 g/kg for soil surface and soil lower layer. [Conclusion]The results of the distribution of soil total nutrients in different soil layers supplied a theory basis for farmland management.展开更多
An asymmetric total synthesis of mansonone P and R were achieved, in whichintroduction of hydroxy substituent at position 2 was performed by Sharpless dihydroxylation ofsily enol ether.
In this paper, by initiative research on local spectral theory of total class wF（p, r, q） operators, we get some important results. Such as total class wF（p, r,q） operators is normaloid operator, the local spectra...In this paper, by initiative research on local spectral theory of total class wF（p, r, q） operators, we get some important results. Such as total class wF（p, r,q） operators is normaloid operator, the local spectral subspace of total class wF（p, r, q） operators is equal to the space EλH（Eλ the Reisz idempotent, with respect to λ1, of T）, total class wF（p, r, q） operators has finite ascent, and so on.展开更多
Total DNA is isolated from Porphyra cells which have been prepared from sea snail enzyme digests of Porphyra thalli. The crude extracts of total DNA are rapidly purified with Wizard DNA Clean-up resin by using modifie...Total DNA is isolated from Porphyra cells which have been prepared from sea snail enzyme digests of Porphyra thalli. The crude extracts of total DNA are rapidly purified with Wizard DNA Clean-up resin by using modified washing solution. DNA bands are clearly observed in the restriction endonuclease patterns of P. yezoensis and P. haitanensis total DNAs. Both P. yezoensis and P. haitanensis have specific DNA bands in the restriction patterns of EcoRI, PastI and HaeIII. According to the band pattern of total DNA, the discrimination between P. yezoensis and P. haitanensis is very easy especially in the restriction pattern of HaeIII. The comparative results indicate that the band pattern of total DNA is a new type and reliable DNA marker for identification and classification of Porphyra species.展开更多
Fertilizers are heavily applied in orchards of the hilly and mountainous topography of South China and may increase nutrient loadings to receiving waters.A simple runoff collecting system was used to measure the effec...Fertilizers are heavily applied in orchards of the hilly and mountainous topography of South China and may increase nutrient loadings to receiving waters.A simple runoff collecting system was used to measure the effects of different fertilization treatments on total N and P concentrations of surface runoff in a Chinese chestnut (Castanea mollissima Blume) orchard in Dongyuan County,Guangdong Province,China.In such orchards,fertilizer was typically applied in two short furrows or pits on either side of each tree.Treatments included three application depths (surface,10cm and 20 cm),and three application rates (low,median and high).Results showed that 90.5% of the runoff water samples had a total N concentration higher than 0.35 mgL^(-1) and 54.2% had a total P concentration higher than 0.1 mgL^(-1).Fertilizer application at all depths and at all but the lowest rate significantly increased total N and P concentrations in runoff water.Fertilization with chemical compound fertilizer at a soil depth of 20cm produced significantly lower (P<0.05) total N concentration in runoff than both surface and 10-cm depth fertilization,and significantly lower (P<0.05) total P concentration in runoff than surface fertilization.Total N and P concentrations in runoff significantly increased with the application rate of organic fertilizers.With the exception of total P concentrations,which were not significantly different between the control and fertilization at a rate of 119 kg P ha-1 in organic form,all the other fertilization treatments produced significantly higher total N and total P concentrations in runoff than the control.A fertilization depth≥20cm and an application rate≤72 kg N ha^(-1) or 119 kg P ha^(-1) for compound organic fertilizer was suggested to substantially reduce N and P runoff losses from hillslope orchards and to protect receiving waters in South China.展开更多
基金Key Project of Chinese Academy of Sciences, No.ZKHZ-3-06
文摘Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matters were analyzed. The results showed that contents of total N, total P and organic matters were generally decreasing with the increase of distance from sample locations to the river channel, and contents of the three items were generally higher in the upper soil layer than that in the lower soil layer. The content variations displayed how flooding functions influenced nutrient matter content variations in floodplain soils since the flood inundation frequencies of the sample locations varied. The correlation analysis displayed that there were remarkable relativities between total N, total P and organic matters within definite spatial distance from the Huolin River channel.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61372172 and 61601518)
文摘Accurate reconstruction from a reduced data set is highly essential for computed tomography in fast and/or low dose imaging applications. Conventional total variation（TV）-based algorithms apply the L1 norm-based penalties, which are not as efficient as Lp（0〈p〈1） quasi-norm-based penalties. TV with a p-th power-based norm can serve as a feasible alternative of the conventional TV, which is referred to as total p-variation（TpV）. This paper proposes a TpV-based reconstruction model and develops an efficient algorithm. The total p-variation and Kullback-Leibler（KL） data divergence, which has better noise suppression capability compared with the often-used quadratic term, are combined to build the reconstruction model. The proposed algorithm is derived by the alternating direction method（ADM） which offers a stable, efficient, and easily coded implementation. We apply the proposed method in the reconstructions from very few views of projections（7 views evenly acquired within 180°）. The images reconstructed by the new method show clearer edges and higher numerical accuracy than the conventional TV method. Both the simulations and real CT data experiments indicate that the proposed method may be promising for practical applications.
基金Supported by Public Project of Science and Technology Ministry(SYKYYW200903)The Ecological Carrying Capacity and Region Ecological Security Regulation of Northeast Industrial Base(2004CB418507)~~
文摘[Objective]The aim was to reveal the spatial distribution characteristics of total nutrients in soil and provide a theoretical basis for farmland management and improvement of crop yield. [Method]GIS technique was used to analyze the spatial distribution characteristics of total C,total N,total P and total K for different soil layers in Liaoning Province. [Result]The results showed that the content of total C,total N,total P decrease from east to west,but the content of total K was high in north district of Liaoning Province. The content of total C,total N,total P and total K was higher in soil surface （0-20 cm） than the lower （20-40 cm）. Total K varied less with soil depth,and its mean content was respectively 17.64 g/kg and 17.08 g/kg for soil surface and soil lower layer. [Conclusion]The results of the distribution of soil total nutrients in different soil layers supplied a theory basis for farmland management.
基金This work was supported by NNSFC(QT program)NNSFC(20372026)+1 种基金SRF for ROCS.SEM,Gansu Science Foundation(No,YS031-A21-001)Lanzhou University Foundation(No.5715220101).
文摘An asymmetric total synthesis of mansonone P and R were achieved, in whichintroduction of hydroxy substituent at position 2 was performed by Sharpless dihydroxylation ofsily enol ether.
文摘In this paper, by initiative research on local spectral theory of total class wF（p, r, q） operators, we get some important results. Such as total class wF（p, r,q） operators is normaloid operator, the local spectral subspace of total class wF（p, r, q） operators is equal to the space EλH（Eλ the Reisz idempotent, with respect to λ1, of T）, total class wF（p, r, q） operators has finite ascent, and so on.
文摘Total DNA is isolated from Porphyra cells which have been prepared from sea snail enzyme digests of Porphyra thalli. The crude extracts of total DNA are rapidly purified with Wizard DNA Clean-up resin by using modified washing solution. DNA bands are clearly observed in the restriction endonuclease patterns of P. yezoensis and P. haitanensis total DNAs. Both P. yezoensis and P. haitanensis have specific DNA bands in the restriction patterns of EcoRI, PastI and HaeIII. According to the band pattern of total DNA, the discrimination between P. yezoensis and P. haitanensis is very easy especially in the restriction pattern of HaeIII. The comparative results indicate that the band pattern of total DNA is a new type and reliable DNA marker for identification and classification of Porphyra species.
基金Project supported by the Science and Technology Department of Guangdong Province,China (No.2004B33301007)the Rockefeller Brothers Fund,America.
文摘Fertilizers are heavily applied in orchards of the hilly and mountainous topography of South China and may increase nutrient loadings to receiving waters.A simple runoff collecting system was used to measure the effects of different fertilization treatments on total N and P concentrations of surface runoff in a Chinese chestnut (Castanea mollissima Blume) orchard in Dongyuan County,Guangdong Province,China.In such orchards,fertilizer was typically applied in two short furrows or pits on either side of each tree.Treatments included three application depths (surface,10cm and 20 cm),and three application rates (low,median and high).Results showed that 90.5% of the runoff water samples had a total N concentration higher than 0.35 mgL^(-1) and 54.2% had a total P concentration higher than 0.1 mgL^(-1).Fertilizer application at all depths and at all but the lowest rate significantly increased total N and P concentrations in runoff water.Fertilization with chemical compound fertilizer at a soil depth of 20cm produced significantly lower (P<0.05) total N concentration in runoff than both surface and 10-cm depth fertilization,and significantly lower (P<0.05) total P concentration in runoff than surface fertilization.Total N and P concentrations in runoff significantly increased with the application rate of organic fertilizers.With the exception of total P concentrations,which were not significantly different between the control and fertilization at a rate of 119 kg P ha-1 in organic form,all the other fertilization treatments produced significantly higher total N and total P concentrations in runoff than the control.A fertilization depth≥20cm and an application rate≤72 kg N ha^(-1) or 119 kg P ha^(-1) for compound organic fertilizer was suggested to substantially reduce N and P runoff losses from hillslope orchards and to protect receiving waters in South China.
文摘完全p-支配集是一个著名的NP-难问题,在无线传感网络中被用于构建无线传感节点的自我保护网络.该文主要研究完全p-支配集在DG(Disk Graph)模型及其特殊模型上的参数复杂性及参数算法设计.首先证明完全p-支配集在顶点度受限的UDG(Unit Disk Graph)上仍是NP-难的.为了深入理解完全p-支配集在UDG模型上的难解性根源,利用参数化规约进一步研究了完全p-支配集在UDG上的参数复杂性.基于难解性根源的分析,最后利用树分解技术和动态规划技术,针对平面图(一种特殊DG模型)上的完全p-支配集,设计了一个时间为O((2p+2)19.1·2^(1-k)k3 n+n3)的精确算法,其中n为给定实例中的顶点个数,k为问题解的大小.
