提出一种支持总最佳连接ABC(Always Best Connected)的新型单播路由机制.由于网络链路参数值的难以精确测量和用户服务质量QoS(Quality of Service)需求的难以准确表达,因此引入区间表示、偏好序列、概率密度函数、满意度函数和评价函...提出一种支持总最佳连接ABC(Always Best Connected)的新型单播路由机制.由于网络链路参数值的难以精确测量和用户服务质量QoS(Quality of Service)需求的难以准确表达,因此引入区间表示、偏好序列、概率密度函数、满意度函数和评价函数加以刻画;考虑到网络运营商业化,引入成本、价格、费用和博弈机制,兼顾用户和网络提供方利益;基于免疫选择和自组织临界变异进化算法寻路,使得各方效用在QoS路由上达到或接近Nash均衡下的Pareto最优.基于NS2进行了仿真实现,在多个实际和虚拟的网络拓扑上与经典路由机制进行了性能对比,结果表明,该机制是可行和有效的.展开更多
The hot deformation characteristics of as-forged Ti−3.5Al−5Mo−6V−3Cr−2Sn−0.5Fe−0.1B−0.1C alloy within a temperature range from 750 to 910℃and a strain rate range from 0.001 to 1 s^(-1) were investigated by hot compre...The hot deformation characteristics of as-forged Ti−3.5Al−5Mo−6V−3Cr−2Sn−0.5Fe−0.1B−0.1C alloy within a temperature range from 750 to 910℃and a strain rate range from 0.001 to 1 s^(-1) were investigated by hot compression tests.The stress−strain curves show that the flow stress decreases with the increase of temperature and the decrease of strain rate.The microstructure is sensitive to deformation parameters.The dynamic recrystallization(DRX)grains appear while the temperature reaches 790℃at a constant strain rate of 0.001 s^(-1) and strain rate is not higher than 0.1 s^(-1) at a constant temperature of 910℃.The work-hardening rateθis calculated and it is found that DRX prefers to happen at high temperature and low strain rate.The constitutive equation and processing map were obtained.The average activation energy of the alloy is 242.78 kJ/mol and there are few unstable regions on the processing map,which indicates excellent hot workability.At the strain rate of 0.1 s^(-1),the stress−strain curves show an abnormal shape where there are two stress peaks simultaneously.This can be attributed to the alternation of hardening effect,which results from the continuous dynamic recrystallization(CDRX)and the rotation of DRX grains,and dynamic softening mechanism.展开更多
Tissue culture has been widely used for mass propagation of Phalaenopsis. However, somaclonal variation occurred during micropropagation process posed a severe problem by affecting product quality. In this study, wild...Tissue culture has been widely used for mass propagation of Phalaenopsis. However, somaclonal variation occurred during micropropagation process posed a severe problem by affecting product quality. In this study, wild type and peloric flower buds of Phalaenopsis hybrids derived from flower stalk nodal culture were used for cDNA-RAPD and cDNA suppression subtractive hybridization analyses in order to study their genetic difference in terms of expressed sequence tags. A total of 209 ESTs from normal flower buds and 230 from mutants were sequenced. These ESTs sequences can be grouped into several functional categories involved in different cellular processes including metabolism, signal transduction, transcription, cell growth and division, protein synthesis, and protein localization, and into a subcat- egory of proteins with unknown function. Cymbidium mosaic virus transcript was surprisingly found expressed fre- quently in the peloric mutant of P. Little Mary. Real-time RT-PCR analysis on selected ESTs showed that in mutant flower buds, a bZIP transcription factor (TGA1a-like protein) was down-regulated, while up-regulated genes include auxin-regulated protein kinase, cyclophilin, and TCP-like genes. A retroelement clone was also preferentially expressed in the peloric mutant flowers. On the other hand, ESTs involved in DNA methylation, chromatin remodeling and post- transcriptional regulation, such as DNA methyltransferase, histone acetyltransferase, ERECTA, and DEAD/DEAH RNA helicase, were enriched in normal flower buds than the mutants. The enriched transcripts in the wild type indicate the down regulation of these transcripts in the mutants, and vice versa. The potential roles of the analyzed transcripts in the development of Phalaenopsis flowers are discussed.展开更多
AIM： TO assess the sampling variability of computeraided, fractal-corrected measures of fibrosis in liver biopsies. METHODS： Samples were derived from six to eight different parts of livers removed from 12 patients ...AIM： TO assess the sampling variability of computeraided, fractal-corrected measures of fibrosis in liver biopsies. METHODS： Samples were derived from six to eight different parts of livers removed from 12 patients with clinically and histologically proven cirrhosis undergoing orthotopic liver transplantation. Sirius red-stained sections with a thickness of 2 μm were digitized using a computer-aided image analysis system that automatically measures the surface of fibrosis, as well as its outline perimeter, fractal surface and outline dimensions, wrinldedness, and Hurst coefficient. RESULTS： We found a high degree of inter-sample variability in the measurements of the surface [coefficient of variation （CV） = 43% ± 13%] and wrinkledness （CV = 28% ± 9%） of fibrosis, but the inter-sample variability of Hurst＇s exponent was low （CV = 14% ± 2%）. CONCLUSION： This study suggests that Hurst＇s exponent might be used in clinical practice as the best histological estimate of fibrosis in the whole organ, and evidences the fact that biopsy sections, which are fundamental for the qualitative diagnosis of chronic hepatitis, play a key role in the quantitative estimate of architectural changes in liver tissue.展开更多
文摘提出一种支持总最佳连接ABC(Always Best Connected)的新型单播路由机制.由于网络链路参数值的难以精确测量和用户服务质量QoS(Quality of Service)需求的难以准确表达,因此引入区间表示、偏好序列、概率密度函数、满意度函数和评价函数加以刻画;考虑到网络运营商业化,引入成本、价格、费用和博弈机制,兼顾用户和网络提供方利益;基于免疫选择和自组织临界变异进化算法寻路,使得各方效用在QoS路由上达到或接近Nash均衡下的Pareto最优.基于NS2进行了仿真实现,在多个实际和虚拟的网络拓扑上与经典路由机制进行了性能对比,结果表明,该机制是可行和有效的.
文摘The hot deformation characteristics of as-forged Ti−3.5Al−5Mo−6V−3Cr−2Sn−0.5Fe−0.1B−0.1C alloy within a temperature range from 750 to 910℃and a strain rate range from 0.001 to 1 s^(-1) were investigated by hot compression tests.The stress−strain curves show that the flow stress decreases with the increase of temperature and the decrease of strain rate.The microstructure is sensitive to deformation parameters.The dynamic recrystallization(DRX)grains appear while the temperature reaches 790℃at a constant strain rate of 0.001 s^(-1) and strain rate is not higher than 0.1 s^(-1) at a constant temperature of 910℃.The work-hardening rateθis calculated and it is found that DRX prefers to happen at high temperature and low strain rate.The constitutive equation and processing map were obtained.The average activation energy of the alloy is 242.78 kJ/mol and there are few unstable regions on the processing map,which indicates excellent hot workability.At the strain rate of 0.1 s^(-1),the stress−strain curves show an abnormal shape where there are two stress peaks simultaneously.This can be attributed to the alternation of hardening effect,which results from the continuous dynamic recrystallization(CDRX)and the rotation of DRX grains,and dynamic softening mechanism.
文摘Tissue culture has been widely used for mass propagation of Phalaenopsis. However, somaclonal variation occurred during micropropagation process posed a severe problem by affecting product quality. In this study, wild type and peloric flower buds of Phalaenopsis hybrids derived from flower stalk nodal culture were used for cDNA-RAPD and cDNA suppression subtractive hybridization analyses in order to study their genetic difference in terms of expressed sequence tags. A total of 209 ESTs from normal flower buds and 230 from mutants were sequenced. These ESTs sequences can be grouped into several functional categories involved in different cellular processes including metabolism, signal transduction, transcription, cell growth and division, protein synthesis, and protein localization, and into a subcat- egory of proteins with unknown function. Cymbidium mosaic virus transcript was surprisingly found expressed fre- quently in the peloric mutant of P. Little Mary. Real-time RT-PCR analysis on selected ESTs showed that in mutant flower buds, a bZIP transcription factor (TGA1a-like protein) was down-regulated, while up-regulated genes include auxin-regulated protein kinase, cyclophilin, and TCP-like genes. A retroelement clone was also preferentially expressed in the peloric mutant flowers. On the other hand, ESTs involved in DNA methylation, chromatin remodeling and post- transcriptional regulation, such as DNA methyltransferase, histone acetyltransferase, ERECTA, and DEAD/DEAH RNA helicase, were enriched in normal flower buds than the mutants. The enriched transcripts in the wild type indicate the down regulation of these transcripts in the mutants, and vice versa. The potential roles of the analyzed transcripts in the development of Phalaenopsis flowers are discussed.
基金Supported by "Michele Rodriguez" Foundation, Institute forQuantitative Measures in Medicine, Milan, Italy
文摘AIM： TO assess the sampling variability of computeraided, fractal-corrected measures of fibrosis in liver biopsies. METHODS： Samples were derived from six to eight different parts of livers removed from 12 patients with clinically and histologically proven cirrhosis undergoing orthotopic liver transplantation. Sirius red-stained sections with a thickness of 2 μm were digitized using a computer-aided image analysis system that automatically measures the surface of fibrosis, as well as its outline perimeter, fractal surface and outline dimensions, wrinldedness, and Hurst coefficient. RESULTS： We found a high degree of inter-sample variability in the measurements of the surface [coefficient of variation （CV） = 43% ± 13%] and wrinkledness （CV = 28% ± 9%） of fibrosis, but the inter-sample variability of Hurst＇s exponent was low （CV = 14% ± 2%）. CONCLUSION： This study suggests that Hurst＇s exponent might be used in clinical practice as the best histological estimate of fibrosis in the whole organ, and evidences the fact that biopsy sections, which are fundamental for the qualitative diagnosis of chronic hepatitis, play a key role in the quantitative estimate of architectural changes in liver tissue.
