A 1.2 W, continuous-wave, continuously-tunable, singly-resonant optical parametric oscillator ͑OPO͒ ͑idler tuning range 3.0-3.8 m͒, pumped by a 10 W continuous-wave Nd:YAG laser, is used in combination with a photoacoustic cell for the detection of ethane. An intracavity solid-state etalon ͑thickness 400 m͒ was used to stabilize the OPO cavity and could be used to mode-hop tune the idler wavelength over 10 cm Ϫ1. The usefulness of the system was demonstrated by determining a detection limit for ethane down to 10 parts per trillion. The selectivity was achieved by making a 24 GHz wide pump laser scan over the ethane absorption line at 2996.9 cm Ϫ1 , after which a Lorentzian fit determined the total area of the absorption signal. Both area value and peak value proved to be linearly depending on the ethane concentration.

This paper is devoted to improve the containment capacity of the Hesgoula south dumping site. The general geology of the dumping site was obtained through geological surveys. Physico-mechanical properties of silty clay and bedrock layers that have a large impact on the stability of the dump were measured by direct shear tests and triaxial tests in laboratory. Then ultimate bearing capacity of the substrate were analyzed and calculated. This paper proposed three capacity expansion and increase plans and used GeoStudio software for comparison. Through computation of the stability of the dump site slope after capacity expansion and increase for each plan, the capacity expansion plan was determined. The capacity expansion and increase plan will solve the problem of the current insufficient containment capacity of the Hesgoula south dumping site, which is of great significance for saving mine transportation costs, improving work efficiency, and reducing grassland occupation.

Nowadays, boron nitride (BN) has attracted a great deal of attention due to its physical and chemical properties, such as high-temperature resistance, oxidation resistance, heat conduction, electrical insulation, and neutron absorption. The unique lamellar, reticular, and tubular morphologies and physicochemical properties of BN make it attractive in the fields of adsorption, catalysis, hydrogen storage, thermal conduction, insulation, dielectric substrate of electronic devices, radiation protection, polymer composites, medicine, etc. Based on this, we propose a novel method to produce boron nitride nanosheets (BNNSs) by a two-step method. The structure and morphology of the prepared BNNSs were characterized by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, XRD, FTIR, etc. The results showed that the prepared BNNSs had high crystallinity and the stripping efficiency of h-BN as well as the performance and yield of BNNSs had been improved, and the cost and environmental pollution of BNNS preparation had been reduced accordingly.

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Herein we report the first catalytic decarbonylation and decarbonylative hydroamination of formamides without using additives enabled by a redox-neutral rare earth catalyst. The protocol displays complete N-aryl/alkenyl formamide-selectivity, thus providing a wide variety of creative uses of the N-formylation and N-deformylation method and opening up new prospects for minimizing waste and controlling the required selectivity in amine transformation events.