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.     

Damping Effect on Waves Propagating Past a Submerged Horizontal Plate and a Vertical Porous Wall

A set of analytical solutions for waves propagating past a combined submerged horizontal plate and vertical porous wall breakwater system is presented. The wave damping effect caused by the horizontal plate induced flow constriction is considered in the analysis. The velocity potentials in each fluid domain are derived based on the linear wave theory and the unknown coefficients are determined from the matching conditions using three sets of orthogonal eigenfunctions. Reflection and transmission coefficients are presented to evaluate the performance of the breakwater system. The analytical solutions in terms of the reflection and transmission coefficients as well as the hydrodynamic force on the vertical porous wall are found in good agreement with published laboratory measurements. In comparison with the solutions without taking into account the wave damping effect, the present analytical solutions significantly improve the accuracy of the wave predictions, especially for the reflected waves.     

Physical Properties of Vegetable Oil and Chlorinated Ethene Mixtures

Laboratory experiments were conducted to investigate the abiotic interactions of soybean oil (SoyOil) and chlorinated ethene (CE) nonaqueous phase liquids (NAPLs). The mixed NAPL density and interfacial tension behaved ideally, as predicted by the volume ratio. The mixed NAPL viscosity increased exponentially from that of the pure CE to that of pure SoyOil as the volume fraction increased. The measured contact angle was highly variable and was unpredictable as a function of the volume composition of the mixed NAPL. The physical property effects indicate that the mobilization of residual CE NAPLs because of SoyOil injection is unlikely. Equilibrium dissolution of CEs from the NAPL mixtures behaved linearly as a function of the mole fraction. Dissolved SoyOil in simulated groundwater enhanced the dissolution of trichloroethene (TCE) during flow tests, increasing the effluent TCE concentration from 141?to?202?mg/L. The ready intermingling of the CE dense nonaqueous phase liquids (DNAPLs) and SoyOil indicate that such interactions may be significant at sites where vegetable oil is injected into DNAPL source areas to enhance in situ anaerobic bioremediation.     

The Therapeutic Process As a Predictor of Change in Patients' Important Relationships During Time-Limited Dynamic Psychotherapy.

Components of the therapeutic process have been shown to be moderately strong predictors of change in patients' global interpersonal functioning during therapy. The authors sought to extend this research by examining how the therapeutic process in time-limited dynamic psychotherapy related to change in patients' perceptions of a specific relationship as rated by the Structural Analysis of Social Behavior. Results showed that ratings of therapist warmth at Session 3 predicted increased warmth and decreased hostility in patient behavior at posttreatment. Therapist warmth at Session 16 was predictive of a decrease in submissive behavior by patients toward their significant other. The importance of the association between the therapeutic process and patients' important interpersonal relationships is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Towards a Formal Account of Reasoning about Evidence: Argumentation Schemes and Generalisations

This paper studies the modelling of legal reasoning about evidence within general theories of defeasible reasoning and argumentation. In particular, Wigmore's method for charting evidence and its use by modern legal evidence scholars is studied in order to give a formal underpinning in terms of logics for defeasible argumentation. Two notions turn out to be crucial, viz. argumentation schemes and empirical generalisations.     

Sydis and the voice/data terminal craze of 1984

In 1984, computing firms saw integrated voice/data terminals (IVDTs) as the solution to the proliferation of new forms of executive communication. The Sydis VoiceStation was hailed as the best of this new class of office machine but, like all IVDTs, it failed. Sydis succumbed to "integration stress," one danger of product development driven by the urge to integrate traditionally discrete functions. Sydis also failed from poor integration of financial and market actors.     

Influence of alumina content on the nucleation crystallization and microstructure of barium fluorphlogopite glass-ceramics based on 8SiO2·YAl2O34MgO2MgF2BaO Part I Nucleation and crystallization behaviour

The effect of varying the aluminium oxide content on the nucleation and crystallization behaviour of barium containing glasses based on 8SiO₂·YAl₂O₃4MgO2MgF₂BaO was investigated in order to develop novel, high strength, machinable glass-ceramics. Nine glasses were synthesized and characterized by Differential Scanning Calorimetry (DSC) Combined Differential Thermal Analysis Thermal Gravimetric Analysis (DTA/TGA), X-ray diffraction (XRD) and dilatometry. The glass transition temperature (T _g) and first peak crystallization temperature (Tp1) reduced with reducing alumina content. Glasses with Y > 1.5 exhibited a second peak crystallization temperature (Tp2). Tp1 was shown to correspond to the crystallization of barium fluorphlogopite (BaSi₆Al₂Mg₆F₂O₁₉) and Tp2 to the crystallization of cordierite (Mg₂Al₂Si₅O₁₈). The thermal expansion coefficient (TEC) was insensitive to alumina content. All the glasses exhibited an optimum nucleation temperature just above T _g, which was thought to be a result of amorphous phase separation (APS). DTA/TGA showed the glasses to undergo weight loss corresponding to silicon tetrafluoride volatilization from the surface, which resulted in a fluorphlogopite deficient surface layer.     

Geometry and damage effects in a composite marine T-joint

The structural integrity and damage tolerance of typical composite T-joints found in ships constructed from glass fibre reinforced plastic was the subject of this investigation. The effect of the geometry of the T-joint on the strain distribution was investigated using finite element (FE) analysis. The results, reported in this paper, showed that the critical strains were significantly affected by the joint geometry. Results of the FE analysis conducted to investigate the effect of disbonds between the filler and overlaminate are also reported. This showed that particular defects led to large changes in the strains in the T-joint structure, which would encourage disbond progression. The FE model was validated by mechanical tests on a representative T-joint, instrumented with surface strain gauges and displacement transducers, into which a range of defects was progressively introduced.     

Part-Set Cuing Effects in Younger and Older Adults.

In 3 experiments, the authors examined part-set cuing effects in younger and older adults. Participants heard lists of category exemplars and later recalled them. Recall was uncued or cued with a subset of studied items. In Experiment 1, participants were cued with some of the category names, and they remembered fewer never-cued categories than a free-recall condition. In Experiment 2, a similar effect was observed for category exemplar cues. There was also an age difference: By some measures, a small number of cues impaired older adults more than younger. Experiment 3 replicated this result and found that older adults were disproportionately slow in the presence of cues. Across experiments, older adults showed robust part-set cuing effects, and sometimes, they were disproportionately impaired by cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

软件EMBA诞生

2004年7月16日,孙伟沉浸在忙碌和兴奋之中。这位美国迈阿密佛罗里达州立大学终身教授的获得者现在是北京航空航天大学软件学院的院长,他喜欢接受挑战性的工作。自从他担任这一职位以来,他一直试图将北航软件学院塑造成为更具有特色的国际性学院,如今,他的这一理想又迈出了更为坚实的一步:北航软件学院将与美国卡内基-梅隆大学和美国项目管理学院签署协议,联手培养硕士级软件营销管理人才,这也是中国第一个软件营销专业。专程为这一专业成立而从美国赶来的 CMM 认证核心创始人之一、