In the laser treatment of a workpiece (9), e.g. for surface hardening, melting, alloying, cladding, welding or cutting, the adverse effect of reflectivity of the surface, when a pure, monochromatic laser (6) is used, is remedied by the simultaneous application of a relatively shorter wavelength beam (1). The two beams (1)(5) may be combined by a beam coupler (4) or may reach the workpiece (9) by separate optical paths (not shown). The shorter wavelength beam (1) improves the coupling efficiency of the higher- powered laser beam (5).

Laser Material Processing

Pt-free electrocatalysts for hydrogen evolution reaction (HER) with high activity and low price are desirable for many state-of-the-art renewable energy devices, such as water electrolysis and photoelectrochemical water splitting cells. However, the design and fabrication of such materials remain a significant challenge. This work reports the preparation of a flexible three-dimensional (3D) film by integrating porous C3N4 nanolayers with nitrogen-doped graphene sheets, which can be directly utilized as HER catalyst electrodes without substrates. This nonmetal electrocatalyst has displayed an unbeatable HER performance with a very positive onset-potential close to that of commercial Pt (8 mV vs 0 mV of Pt/C, vs RHE @ 0.5 mA cm–2), high exchange current density of 0.43 mA cm–2, and remarkable durability (seldom activity loss >5000 cycles). The extraordinary HER performance stems from strong synergistic effect originating from (i) highly exposed active sites generated by introduction of in-plane pores into C...

Porous C3N4 nanolayers@N-graphene films as catalyst electrodes for highly efficient hydrogen evolution.

Electrocatalysis developments for hydrogen evolution reaction in alkaline solutions – A Review

https://pure.tue.nl/ws/files/101607113/1_s2.0_S0360128516300260_main.pdf

Electrocatalysts for the generation of hydrogen, oxygen and synthesis gas

Multiferroic bismuth ferrite-based materials for multifunctional applications: Ceramic bulks, thin films and nanostructures

https://uwaterloo.ca/centre-advanced-materials-joining/sites/ca.centre-advanced-materials-joining/files/uploads/files/hang_growth_behaviour.pdf

Growth behavior of Cu/Al intermetallic compounds and cracks in copper ball bonds during isothermal aging.

Rapid pressureless low-temperature sintering of Ag nanoparticles for high-power density electronic packaging

http://www.cbe.buffalo.edu/people/pdfPub.jsp?id=3498

Ni–CeO2 composite cathode material for hydrogen evolution reaction in alkaline electrolyte

Formation mechanism and orientation of Cu3Sn grains in Cu–Sn intermetallic compound joints

Wafer bonding using Sn interlayer and silicon bond components with Ti/Ni/Cu metallization was achieved by ultrasonic bonding at ambient temperature for 4 s under 0.6 MPa. High-melting-point joint which fully consisted of Cu3Sn intermetallic compounds was formed with a high shear strength of 65.8 MPa and a low electrical resistivity of 67.3 μΩ · cm. Experimental results showed that ultrasonic vibration induced steep temperature rise at rubbing interface, melting solid solder, and sequent ultrasonic effects at the liquid Sn/solid Cu interface dominated the mechanism and kinetics of rapid formation of Cu3Sn joint.

Chunqing Wang

Papers

Growth behavior of Cu/Al intermetallic compounds and cracks in copper ball bonds during isothermal aging.

Rapid pressureless low-temperature sintering of Ag nanoparticles for high-power density electronic packaging

Ni–CeO2 composite cathode material for hydrogen evolution reaction in alkaline electrolyte

Formation mechanism and orientation of Cu3Sn grains in Cu–Sn intermetallic compound joints

Rapid formation of Cu/Cu3Sn/Cu joints using ultrasonic bonding process at ambient temperature