SiC-NANOPARTICLE DISPERSED COMPOSITE SOLDER BUMPS FABRICATED BY ELECTROPLATING

SiC-mixed Sn–58Bi composite solder bumps were successfully fabricated via an electroplating process. For the composite solder bump fabrication, ultrasonically dispersed SiC nanoparticles were added to the plating solutions. DSC analysis indicated that the melting temperature of SiC-mixed Sn–58Bi solders was the same as that of the non-mixed Sn–58Bi. Shear strengths of Sn–58Bi+SiC solder bumps were 6% higher than that of non-mixed solder bumps. The thicknesses of intermetallic compound were almost the same for both Sn–58Bi and Sn–58Bi+SiC samples. The Sn–58Bi+SiC composite solder bumps had finer lamellar structures than non-mixed Sn–58Bi. From the fracture surface analysis, fracture occurred at solder bump matrix, not at joint interface. Therefore, the addition of the SiC nanoparticles in the Sn–58Bi solders decreased the grain sizes, which increased the shear strengths.Sn–58Bi, SiC nanoparticles, Pb-free solders, solder bump, electroplating

Variability in empathic fear response among 11 inbred strains of mice

Empathy is an important emotional process that involves the ability to recognize and share emotions with others. We have previously developed an observational fear learning (OFL) behavioral assay to measure empathic fear in mice. In the OFL task, a mouse is conditioned for context-dependent fear when it observes a conspecific demonstrator receiving aversive stimuli. In the present study, by comparing 11 different inbred mouse strains that are commonly used in the laboratory, we found that empathic fear response was highly variable between different strains. Five strains - C57BL/6J, C57BL/6NTac, 129S1/SvImJ, 129S4/SvJae and BTBR T+ Itpr3tf/J - showed observational fear (OF) responses, whereas AKR/J, BALB/cByJ, C3H/HeJ, DBA/2J, FVB/NJ and NOD/ShiLtJ mice exhibited low empathic fear response. Importantly, day 2 OF memory was significantly correlated with contextual memory in the classical fear conditioning among the 11 strains. Innate differences in anxiety, locomotor activity, sociability and preference for social novelty were not significantly correlated with OFL. Interestingly, early adolescent C57BL/6J mice exhibited an increase in acquisition of OF. The level of OFL in C57BL/6J strain was not affected by sex or strains of the demonstrator. Taken together, these data strongly suggest that there are naturally occurring OFL-specific genetic variations modulating empathic fear behaviors in mice. The identification of causal genes may uncover novel genetic pathways and underlying neural mechanisms that modulate empathic fear and, ultimately, provide new targets for therapeutic intervention in human mental disorders associated with impaired empathy. Wide phenotypic variation in empathic fear response among 11 inbred mouse strains. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society115181sciescopu

Exceptional load-bearing capability of Al FPCB/Cu FPCB lap joints using instantaneous laser-based large area facial soldering: Experimental and numerical investigations

This study introduces a novel method for integrating aluminum flexible printed circuit boards (FPCBs) and copper FPCBs into battery management systems (BMS) using and instantaneous large area facial laser source soldering. Achieving a robust bonding strength of 65 MPa involved applying 600 W of laser power for 2 s, enhancing atom diffusion and promoting intermetallic compound (IMC) growth. Finite Element Method (FEM) simulations revealed variations in heat transfer between Al and Cu, affecting IMC thickness at interfaces. Formation of the (Cu, Ni)3Sn4 phase within solder, and variations in laser output significantly influenced solder joint orientation and Al electrode nucleation. Excessive laser power (>800 W) caused critical damage, such as delamination at the Al-PI interface, altering fracture modes and bonding strength. Furthermore, with a detailed examination of the laser soldering phenomenon through both experimental and numerical investigations, this study provides a thorough understanding of the different soldering mechanisms in conventional reflow soldering compared to instantaneous uniform large-area heat source laser soldering. These insights provide new design and material considerations to replace the conventional wiring harness with Al/Cu FPCB lap joints which optimize the circuitry and reducing BMS volume

Experimental observation of the non-diffusive avalanche-like electron heat transport events and their dynamical interaction with the shear flow structure

We present experimental observations suggesting that non-diffusive avalanche-like transport events are a prevalent and universal process in the electron heat transport of tokamak plasmas. They are observed in the low confinement mode and the weak internal transport barrier plasmas in the absence of magnetohydrodynamic instabilities. In addition, the electron temperature profile corrugation, which indicates the existence of the E x B shear flow layers, is clearly demonstrated as well as their dynamical interaction with the avalanche-like events. The measured width of the profile corrugation is around 45(rho i), implying the mesoscale nature of the structure

Raman Markers from Silver Nanowire Crossbars

We fabricated silver nanowire crossbars partially decorated with silver nanoparticles via a double-step transversal capillary transfer microprinting approach and demonstrated their polarization-dependent surface-enhanced Raman scattering (SERS) properties. We demonstrated that SERS intensity of nanowire junctions and nanowire nanoparticle junctions can be turned on/off on demand by the rotation of the polarization plane, which excites specific transversal plasmon resonances and initiates selective excitation/suppression of central and auxiliary nanostructured junctions. We suggest that massive fabrication of such addressable crossbar nanojunctions is important for exploiting these SERS markers for chemical and biological detection assays.close191