基于Le Gall 5/3滤波器提出了一种逐行小波变换方法,处理器从图像节点SD卡逐行读出图像信息,完成多级变换后将变换结果行写入SD卡。该方法 SRAM内存需求低,且仅涉及定点整数乘法、加法及移位操作。应用所提方法对一幅256像素×256...基于Le Gall 5/3滤波器提出了一种逐行小波变换方法,处理器从图像节点SD卡逐行读出图像信息,完成多级变换后将变换结果行写入SD卡。该方法 SRAM内存需求低,且仅涉及定点整数乘法、加法及移位操作。应用所提方法对一幅256像素×256像素仔猪灰度图像进行小波变换实验,结果表明,该方法以合理的定点运算代价换取了3.968 KB的SRAM开销以及8.718 s的时间开销。为基于小波变换的WMSN节点图像压缩奠定了基础,使农业生产图像在低带宽WMSN上高效传输成为可能。展开更多
以氨基-1,2,4-三唑和2-偕二硝甲基-5-硝基四唑(HDNMNT)为原料,通过中和反应合成出两种新型含能离子盐——2-偕二硝甲基-5-硝基四唑3-氨基-1,2,4-三唑盐(3-ATDNMNT)和2-偕二硝甲基-5-硝基四唑4-氨基-1,2,4-三唑盐(4-ATDNMNT),收率分别为9...以氨基-1,2,4-三唑和2-偕二硝甲基-5-硝基四唑(HDNMNT)为原料,通过中和反应合成出两种新型含能离子盐——2-偕二硝甲基-5-硝基四唑3-氨基-1,2,4-三唑盐(3-ATDNMNT)和2-偕二硝甲基-5-硝基四唑4-氨基-1,2,4-三唑盐(4-ATDNMNT),收率分别为95.4%和96.7%;利用FT-IR、1 H NMR、13C NMR、15 N NMR及元素分析等方法对其结构进行表征;采用量子化学方法计算了3-ATDNMNT和4-ATDNMNT的爆轰性能;在标准状态下(膨胀比为70∶1),利用最小自由能原理,分别计算了两种离子盐在丁羟复合推进剂中的能量性能。结果表明,3-ATDNMNT的爆速和爆压分别为8.587km/s和33.58GPa,4-ATDNMNT的爆速和爆压分别为8.693km/s和34.31GPa。以3-ATDNMNT部分取代丁羟复合推进剂中的AP后,丁羟复合推进剂的理论比冲可达2 635.7N·s/kg。以4-ATDNMNT部分取代丁羟复合推进剂中的AP后,当HTPB、Al、AP及4-ATDNMNT各组分质量分数分别为10%、5%、15%及70%时,获得该丁羟复合推进剂的最高理论比冲为2 677.2N·s/kg。展开更多
A hydrolyte of magnesium 7 methoxyl 4′ hydroxylisoflavone 3′ sulfonate ([Mg(H 2O) 6](C 16 H 11 O 4SO 3) 2·10H 2O) was synthesized and its crystal structure was determined by X ray diffractio...A hydrolyte of magnesium 7 methoxyl 4′ hydroxylisoflavone 3′ sulfonate ([Mg(H 2O) 6](C 16 H 11 O 4SO 3) 2·10H 2O) was synthesized and its crystal structure was determined by X ray diffraction analyses. The crystal belongs to triclinic crystal system, space group P ī with cell constants a =0 7359(1) nm, b =0 9935(1) nm, c = 1 6335(2) nm, α =91 16(1)°, β =92 07(1)°, γ =106 53(1)°, V =1 1436(2) nm 3 and Z =1. The results show that the title compound consists of [Mg(H 2O) 6] 2+ , C 16 H 11 O 4SO - 3 and H 2O. Mg(II) is located at the symmetry center of the title compound. [Mg(H 2O) 6] 2+ , C 16 H 11 O 4SO - 3 and H 2O form fourteen kinds of hydrogen bonds. The distance of 0 351 nm between parallel isoflavone rings shows a π π stacking interaction. The hydrogen bonds and π π stacking interaction lead to supramolecular formation with three dimensional network structure. The title compound was also characterized by IR and 1H NMR spectra.展开更多
The Filtering Grid Scale （FGS） of sub-grid scale models does not match with the theoretical Proper FGS （PFGS） because of the improper mesh. Therefore, proper Large Eddy Simulation （LES） Mesh is very decisive for...The Filtering Grid Scale （FGS） of sub-grid scale models does not match with the theoretical Proper FGS （PFGS） because of the improper mesh. Therefore, proper Large Eddy Simulation （LES） Mesh is very decisive for better results and more economical cost. In this work, the purpose is to provide an adaptive control strategy for proper LES mesh with turbulence theory and CFD methods. A new expression of PFGS is proposed on the basis of -5/3 law of inertial sub-range and the proper mesh of LES can be built directly from the adjustment of RANS mesh. A benchmark of the backward facing step flow at Re = 5147 is provided for application and verification. There are three kinds of mesh sizes, including the RANS mesh, LAM （LES of adaptive-control mesh）, LFM （LES of fine mesh）, employed here. The grid number of LAM is smaller than those of LFM evidently, and the results of LAM are in a good agreement with those of DNS and experiments. It is revealed that the results of LAM are very close to those of LFM. The conclusions provide positive evidences for the novel strategy.展开更多
文摘以氨基-1,2,4-三唑和2-偕二硝甲基-5-硝基四唑(HDNMNT)为原料,通过中和反应合成出两种新型含能离子盐——2-偕二硝甲基-5-硝基四唑3-氨基-1,2,4-三唑盐(3-ATDNMNT)和2-偕二硝甲基-5-硝基四唑4-氨基-1,2,4-三唑盐(4-ATDNMNT),收率分别为95.4%和96.7%;利用FT-IR、1 H NMR、13C NMR、15 N NMR及元素分析等方法对其结构进行表征;采用量子化学方法计算了3-ATDNMNT和4-ATDNMNT的爆轰性能;在标准状态下(膨胀比为70∶1),利用最小自由能原理,分别计算了两种离子盐在丁羟复合推进剂中的能量性能。结果表明,3-ATDNMNT的爆速和爆压分别为8.587km/s和33.58GPa,4-ATDNMNT的爆速和爆压分别为8.693km/s和34.31GPa。以3-ATDNMNT部分取代丁羟复合推进剂中的AP后,丁羟复合推进剂的理论比冲可达2 635.7N·s/kg。以4-ATDNMNT部分取代丁羟复合推进剂中的AP后,当HTPB、Al、AP及4-ATDNMNT各组分质量分数分别为10%、5%、15%及70%时,获得该丁羟复合推进剂的最高理论比冲为2 677.2N·s/kg。
基金ProjectsupportedbytheNaturalScienceFoundationofShaanxiProvince (No .2 0 0 1K11 G5 )
文摘A hydrolyte of magnesium 7 methoxyl 4′ hydroxylisoflavone 3′ sulfonate ([Mg(H 2O) 6](C 16 H 11 O 4SO 3) 2·10H 2O) was synthesized and its crystal structure was determined by X ray diffraction analyses. The crystal belongs to triclinic crystal system, space group P ī with cell constants a =0 7359(1) nm, b =0 9935(1) nm, c = 1 6335(2) nm, α =91 16(1)°, β =92 07(1)°, γ =106 53(1)°, V =1 1436(2) nm 3 and Z =1. The results show that the title compound consists of [Mg(H 2O) 6] 2+ , C 16 H 11 O 4SO - 3 and H 2O. Mg(II) is located at the symmetry center of the title compound. [Mg(H 2O) 6] 2+ , C 16 H 11 O 4SO - 3 and H 2O form fourteen kinds of hydrogen bonds. The distance of 0 351 nm between parallel isoflavone rings shows a π π stacking interaction. The hydrogen bonds and π π stacking interaction lead to supramolecular formation with three dimensional network structure. The title compound was also characterized by IR and 1H NMR spectra.
基金Project supported by the National Natural Science Foundation of china (Grant No. 50776056)the National High Technology Research and Development of China (863 Program,Grant No. 2009AA05Z201)
文摘The Filtering Grid Scale （FGS） of sub-grid scale models does not match with the theoretical Proper FGS （PFGS） because of the improper mesh. Therefore, proper Large Eddy Simulation （LES） Mesh is very decisive for better results and more economical cost. In this work, the purpose is to provide an adaptive control strategy for proper LES mesh with turbulence theory and CFD methods. A new expression of PFGS is proposed on the basis of -5/3 law of inertial sub-range and the proper mesh of LES can be built directly from the adjustment of RANS mesh. A benchmark of the backward facing step flow at Re = 5147 is provided for application and verification. There are three kinds of mesh sizes, including the RANS mesh, LAM （LES of adaptive-control mesh）, LFM （LES of fine mesh）, employed here. The grid number of LAM is smaller than those of LFM evidently, and the results of LAM are in a good agreement with those of DNS and experiments. It is revealed that the results of LAM are very close to those of LFM. The conclusions provide positive evidences for the novel strategy.
