Microstructure evolution of the Sn–Ag–y%Cu interconnect

The lead free Sn–Ag–y%Cu (y = 0.0, 0.5, 1.0 and 2.0) interconnect interfacial microstructures and the microstructure evolution under thermal treatment (isothermal aging, 150 °C/1000 h) were studied in detail by using surface microetching microscopy and cross section microscopy. The corresponding mechanical and reliability behaviors were evaluated by performing shear test and fracture mode analysis before and after the thermal treatment. The results indicate: (i) The interconnects could have different microstructures and intermetallic compound (IMC), depending on the Cu content. The Cu–Sn IMC could have microstructures that were clusters or protrusion-like, Augustine grass leaf-like, scissor-like, tweezers-like, etc. (ii) Ag₃Sn IMCs were not observed at time zero for any interconnect groups, but they occurred after the aging for all groups. The Ag₃Sn IMC could have different microstructures, again depending on Cu content. For low Cu content, the Ag₃Sn IMCs were granules or nodules; for higher Cu content, Ag₃Sn IMCs were plate-like. (iii) The growth of Ag₃Sn plates was promoted by the growth of Cu–Sn IMCs, but indirectly linked to the Cu content. (iv) High Cu content (1.0 wt% and higher) could degrade the mechanical and reliability performances of the LF interconnect by providing a brittle joint, which was mainly achieved through the substantial growth of Cu–Sn IMCs and Ag₃Sn plates.     

Quantum-mechanical effects and gate leakage current of nanoscale n-type FinFETs: A 2d simulation study

This paper simulates a kind of new sub-50 nm n-type double gate MOS nanotransistors by solving coupled Poisson-Schrödinger equations in a self-consistent manner with a finite element method, and presents a systematic simulation-based study on quantum-mechanical effects, gate leakage current of FinFETs. The simulation results indicate that the deviation from the classical model becomes more important as the gate oxide, gate length and Fin channel width becomes thinner and the Fin channel doping increases. Gate tunneling current density reduces with the body thickness decreasing. Excessive scaling increases the gate current below Fin thickness of 5 nm. The gate current can be dramatically reduced beyond 10¹⁷ cm⁻³ with the Fin body doping increasing. In order to understand the influence of electron confinement, quantum mechanical simulation results are also compared with the results from the classical approach. Our simulation results indicate that quantum mechanical simulation is essential for the realistic optimization of the FinFET structure.     

谈C语言中的图形模式

C语言不仅具有高级语言的功能,而且还具有低级语言特点,它可以直接控制显示屏幕等系统硬件。因此,可能利用C语言提供的图形函数,在图形模式下开发各种图形软件。     

Iron-rich intermetallic phases and their role in casting defect formation in hypoeutectic Al-Si alloys

Iron is the most common and detrimental impurity in aluminum casting alloys and has long been associated with an increase in casting defects. While the negative effects of iron are clear, the mechanism involved is not fully understood. It is generally believed to be associated with the formation of Fe-rich intermetallic phases. Many factors, including alloy composition, melt superheating, Sr modification, cooling rate, and oxide bifilms, could play a role. In the present investigation, the interactions between iron and each individual element commonly present in aluminum casting alloys, were investigated using a combination of thermal analysis and interrupted quenching tests. The Fe-rich intermetallic phases were characterized using optical microscope, scanning electron microscope, and electron probe microanalysis (EPMA), and the results were compared with the predictions by Thermocalc. It was found that increasing the iron content changes the precipitation sequence of the β phase, leading to the precipitation of coarse binary β platelets at a higher temperature. In contrast, manganese, silicon, and strontium appear to suppress the coarse binary β platelets, and Mn further promotes the formation of a more compact and less harmful α phase. They are therefore expected to reduce the negative effects of the β phase. While reported in the literature, no effect of P on the amount of β platelets was observed. Finally, attempts are made to correlate the Fe-rich intermetallic phases to the formation of casting defects. The role of the β phase as a nucleation site for eutectic Si and the role of the oxide bifilms and AlP as a heterogeneous substrate of Fe intermetallics are also discussed.     

九江市矿产资源开发利用现状与对策

分析了江西省九江市矿产资源的基本特点、开发利用现状及存在的问题,提出了九江市科学开发利用矿产资源的对策.     

Propulsive performance of a fish-like travelling wavy wall

Summary. A numerical simulation is performed to investigate the viscous flow over a smooth wavy wall undergoing transverse motion in the form of a streamwise travelling wave, which is similar to the backbone undulation of swimming fish. The objective of this study is to elucidate hydrodynamic features of the flow structure over the travelling wavy wall and to get physical insights to the understanding of fish-like swimming mechanisms in terms of drag reduction and optimal propulsive efficiency. The effect of phase speed, amplitude and Reynolds number on the flow structure over the wavy wall, the drag force acting on the wall, and the power consumption required for the propulsive motion of the wall is investigated. The phase speed and the amplitude, which are two important parameters in this problem, predicted based on the optimal propulsive efficiency agree well with the available data obtained for the wave-like swimming motion of live fish in nature.     

Applications of optimal mathematic-physical models in metallurgical manufacture scheduling system at Baosteel

The transfer of mass flow between ironmaking and steelmaking process at Baoshan Iron and Steel Co. Ltd. has been analyzed. The mathematic-physical models of transport scheduling for hot metal manufacturing have been researched combined with the practical problem in the metallurgical manufacture procedure. Taking into account these models, the scheduling software has been designed, programmed and tested on-line. The new automation system of production scheduling has been implemented successfully at Baosteel, which produces a great economic benefit.     

The hydration characteristics and expansion machanism of expansive cement at low<Emphasis Type="Italic">W/B</Emphasis> ratio

The hydration characteristics and expansion impetus of three kinds of cement paste under free-and confined-curing conditions were investigated, which were respectively mixed with three different kinds of expansive agent at low W/B ratio. The results show that the hydration products of pure cement paste and paste mixed with expansive agent are same, but the amount of hydration products, un-hydrated C₃S and C₂S are obviously different at the same hydration age. At 3 d age, the amount of CH in pure cement paste is less than that of paste mixed with expansive agent, but it is reverse when at 28 d age. The amount of AFt at 3d and 28d age in pure cement paste is less than those of paste mixed with expansive agent. Regardless of under free- or confined-curing condition, the amount of ettringite produced varies little since 3d age. The joint effect of the tumefaction of gel-ettringite due to water absorption and the expansive pressure on the pore caused by the crystalloid ettringite is the cause of the volume expansion of cement paste, and the former effect is much greater than the latter. LU Lin-nu : Born in 1972 Funded by 973 High-tech Project of China (No. 2001CB610704-2) and the Natural Science Foundation of Hubei Province(No. 2002AB075)     

用InTouch、MATLAB和VC++开发工业监控系统软件

本文针对工业自动控制的需要开发了基于InTouch、MATULB以及VC 三者混合编程的具有普通分散控制系统不具备的较完善控制功能(例如人工神经网络控制)的控制系统监控软件。本系统可通过通信连入控制网络。开发时充分利用了三者各自的优点。使本系统具有较高的开发效率和应用价值。     

Reconfigurable Web wrapper agents

Web wrapper agents exploit online Web data sources, facilitating information integration and reuse. With the DeepSpot Agent Toolbox, users can automate virtually all types of Web browsing sessions simply by browsing the target Web sites.