This paper investigates the behaviour of traffic flow in traffic systems with a new model based on the NaSch model and cluster approximation of mean-field theory. The proposed model aims at constructing a mapping rela...This paper investigates the behaviour of traffic flow in traffic systems with a new model based on the NaSch model and cluster approximation of mean-field theory. The proposed model aims at constructing a mapping relationship between the microcosmic behaviour and the macroscopic property of traffic flow. Results demonstrate that scale-free phenomenon of the evolution network becomes obvious when the density value of traffic flow reaches at the critical point of phase transition from free flow to traffic congestion, and jamming is limited in this scale-free structure.展开更多
采用光学显微镜、电子显微镜和动态力学分析等方法研究Bi含量对直径为400μm、高度为200μm的无铅Cu/Sn-0.3Ag-0.7Cu(SAC0307)/Cu微尺度焊点的显微组织及蠕变性能的影响。结果表明:当焊点中Bi含量较低(1%(质量分数))时,其基体组织细小,C...采用光学显微镜、电子显微镜和动态力学分析等方法研究Bi含量对直径为400μm、高度为200μm的无铅Cu/Sn-0.3Ag-0.7Cu(SAC0307)/Cu微尺度焊点的显微组织及蠕变性能的影响。结果表明:当焊点中Bi含量较低(1%(质量分数))时,其基体组织细小,Cu_6Sn_5为粗大块状,Ag_3Sn分布不均匀;当焊点中Bi含量较多(3%(质量分数))时,基体组织与Cu_6Sn_5进一步细化,Ag_3Sn在细化的同时分布更均匀,界面扇贝状IMC层更平直。另外,温度为80~125℃、应力为8~15 MPa条件下,拉伸蠕变试验得到SAC0307微焊点的蠕变激活能(Q)和蠕变应力指数(n)分别为82.9 k J/mol和4.35;当钎料中Bi含量由1.0%增加到3.0%时,焊点的Q值从89.2 k J/mol增加到94.6 k J/mol,n值由4.48增加到4.73,钎焊接头的抗蠕变能力明显提高,所有焊点的蠕变变形机制主要受位错攀移控制。展开更多
A new dual-mode transmission networks （DMTN） based on broad-storage architecture for digital television （DTV） is proposed, in which the primary TV network is superimposed by a complementary framework based on broa...A new dual-mode transmission networks （DMTN） based on broad-storage architecture for digital television （DTV） is proposed, in which the primary TV network is superimposed by a complementary framework based on broad-storage TV （BSTV）. The necessity of congregating hot TV resources is discussed via analyzing the scale-free properties in DMTN. The self-organized parallel broadcasting technology （SPBT） and the uniform content locator （UCL） are studied to utilize availably transmission channels and to help consumers to communicate with each other expediently. Experimental results show that DMTN can provide not only traditional TV services on schedule, but also digital interactive TV services on demand by using a single channel.展开更多
基金supported by the National Basic Research Program of China (973) (Grant No 2006CB705500)the National Natural Science Foundation of China (Grant No 70671008)
文摘This paper investigates the behaviour of traffic flow in traffic systems with a new model based on the NaSch model and cluster approximation of mean-field theory. The proposed model aims at constructing a mapping relationship between the microcosmic behaviour and the macroscopic property of traffic flow. Results demonstrate that scale-free phenomenon of the evolution network becomes obvious when the density value of traffic flow reaches at the critical point of phase transition from free flow to traffic congestion, and jamming is limited in this scale-free structure.
文摘采用光学显微镜、电子显微镜和动态力学分析等方法研究Bi含量对直径为400μm、高度为200μm的无铅Cu/Sn-0.3Ag-0.7Cu(SAC0307)/Cu微尺度焊点的显微组织及蠕变性能的影响。结果表明:当焊点中Bi含量较低(1%(质量分数))时,其基体组织细小,Cu_6Sn_5为粗大块状,Ag_3Sn分布不均匀;当焊点中Bi含量较多(3%(质量分数))时,基体组织与Cu_6Sn_5进一步细化,Ag_3Sn在细化的同时分布更均匀,界面扇贝状IMC层更平直。另外,温度为80~125℃、应力为8~15 MPa条件下,拉伸蠕变试验得到SAC0307微焊点的蠕变激活能(Q)和蠕变应力指数(n)分别为82.9 k J/mol和4.35;当钎料中Bi含量由1.0%增加到3.0%时,焊点的Q值从89.2 k J/mol增加到94.6 k J/mol,n值由4.48增加到4.73,钎焊接头的抗蠕变能力明显提高,所有焊点的蠕变变形机制主要受位错攀移控制。
基金Sponsored by the National High Technology Research and Development Program of China(2007AA01Z151)the National Natural Science Foundation of China(60272014)
文摘A new dual-mode transmission networks （DMTN） based on broad-storage architecture for digital television （DTV） is proposed, in which the primary TV network is superimposed by a complementary framework based on broad-storage TV （BSTV）. The necessity of congregating hot TV resources is discussed via analyzing the scale-free properties in DMTN. The self-organized parallel broadcasting technology （SPBT） and the uniform content locator （UCL） are studied to utilize availably transmission channels and to help consumers to communicate with each other expediently. Experimental results show that DMTN can provide not only traditional TV services on schedule, but also digital interactive TV services on demand by using a single channel.
