Investigation of the factors affecting the limit of detection of laser-induced breakdown spectroscopy for surface inspection

Laser-induced breakdown spectroscopy(LIBS) was examined to detect a trace substance adhered onto Al alloys for the surface inspection of materials to be adhesively bonded. As an example of Si contamination, silicone oil was employed and sprayed onto substrates with a controlled surface concentration. LIBS measurements employing nanosecond UV pulses(λ?=?266 nm) and an off-axis emission collection system with different detecting heights were performed. Because surface contaminants are involved in the plasma formed by laser ablation of the substrates, the relative contribution of the surface contaminants and the substrates to the plasma emission could be changed depending on the conditions for plasma formation. The limit of detection(LOD) was evaluated under several detecting conditions for investigating the factors that affected the LOD. A significant factor was the standard deviation values of signal intensities obtained for the clean substrates. This value varied depending on the measurement conditions.For the Al alloy(A6061), the smallest LOD obtained was 0.529 μg?·?cm^(-2). Furthermore, an improved LOD(0.299 μg?·?cm^(-2)) was obtained for the Al alloy with a lower Si content.

Recent advances in electrooxidative radical transformations of alkynes

During the past few years,electrochemical oxidative reactions through radical intermediates have emerged as an environmentally-benign,powerful platform for the facile formation of C–E(E=C,N,S,Se,O and Hal)bonds through singleelectron-transfer(SET)processes at the electrodes.Functionalized unsaturated molecules and unusual structural motifs can,for instance,be directly constructed under exceedingly mild reaction conditions through initial radical attack onto alkynes.This minireview highlights the recent advances in electrooxidation in radical reactions until June 2022,with a particular focus on radical additions onto alkynes.

Electrolyser design controls position-divergent C–H carboxylation

In recent years,molecular electrochemistry has undergone a remarkable renaissance to surface as a sustainable strategy for organic synthesis and catalysis,gaining considerable momentum by the use of renewable forms of energy[1,2].Modern organic electrochemistry has the unique power to control chemo-,regio-,and position-selectivities through the judicious choice of the electrode material,the applied potential or an additional catalyst,among others[1,2].Despite the major advances in molecular electrochemistry,these approaches continue to predominantly rely on non-renewable fossil resources.

Nickela-electrocatalyzed sulfide and phosphine oxygenations with water

Molecular electrochemistry has emerged as an environmentally-friendly platform.While major recent momentum was gained in electrocatalyzed bond activations by earth-abundant 3 d transition metals[1],cost-effective nickela-electrocatalysis continuous to be underdevelopment for electrocatalysis[2].Nickel is an essential component of metalloproteins involved in catalytic aerobic oxygenation processes,for which nickel-dioxygen species were proposed as the key catalytic species[3].