A facile catalysis-free method has been utilized to synthesize functional samarium hexaboride (SmB6) nanowires. Structural characterization shows that the nanowires are single-crystalline SmB6 with the [1 0 0] growth direction. These nanowires exhibit a low turn-on electric field of 4.2 V µm−1 based on the 10 µA cm−2 current density criterion at room temperature (RT). The effect of temperature on the field emission properties of the SmB6 nanowires has also been investigated. The turn-on field of the SmB6 nanowires is found to decrease from 4.2 to 2.7 V µm−1 (at 10 µA cm−2); meanwhile, the estimated field enhancement factor increases from 2207 to 4741 clearly with an increase from RT to 573 K. This dependence might be due to the change in the effective work function of the nanowires with temperature.

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Abstract. C1/C2 organohalogens (organohalogens with one or two carbon atoms) can have significant environmental toxicity and ecological impact, such as carcinogenesis, ozone depletion and global warming. Natural halogenation processes have been identified for a wide range of natural organic matter, including soils, plant and animal debris, algae, and fungi. Yet, few have considered these organohalogens generated from the ubiquitous bacteria, one of the largest biomass pools on earth. Here, we report and confirm the formation of chloroform (CHCl 3 ) dichloro-acetonitrile (CHCl 2 CN), chloral hydrate (CCl 3 CH(OH) 2 ) and their brominated analogues by direct halogenation of seven strains of common bacteria and nine cellular monomers. Comparing different major C stocks during litter decomposition stages in terrestrial ecosystems, from plant litter, decomposed litter, to bacteria, we found increasing reactivity for nitrogenous organohalogen yield with decreasing C/N ratio. Our results raise the possibility that natural halogenation of bacteria represents a significant and overlooked contribution to global organohalogen burdens. As bacteria are decomposers that alter the C quality by transforming organic matter pools from high to low C/N ratio and constitute a large organic N pool, the bacterial activity is expected to affect the C, N, and halogen cycling through natural halogenation reactions.

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As an essential component of sludge, soil organic matter is also the most energetic component of the sludge solid phase. However, the organic content of sludge reduces the engineering qualities of cement-cured sludge and restricts the cement curing reaction process. Humic acid (HA) was employed in tests conducted indoors to mimic the organic material naturally present in the waste sludge. The effect of different HA and cement dosages was investigated for the strength of the dredged sludge. The mechanism of the effect of HA on the strength of cement-solidified dredged sludge (CDS) was examined in conjunction with the findings of unconfined compression strength (UCS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). (1)The overall unconfined compressive strength of CDS decreased after the addition of HA. (2) The strength of the HA sludge-cured body exhibits an increasing trend with the increase in cement input. The strength of sludge cured bodies with high HA content can be enhanced by correctly increasing the curing agent. (3) HA acts as a cement retarder, delaying hydration time by adhering to the surface of cement particles to form an adsorption coating. (4) As observed by SEM, the conversion of C-S-H to foil-like is hindered by HA in the silt, and its microscopic morphology changes with the change of HA content, which is manifested by the decrease of CDS intensity on a macroscopic scale.