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Abstract: We have investigated the threshold properties of Rubidium blue bronze Rb0.3MoO3 under high dc electric field in a large temperature range 20–150 K. The second threshold fields have been observed at temperature up to 102.4 K, and have quasi-linear relationships with temperatures 20–45 K and 55–100 K, respectively. A novel crossover platform has been found firstly in the temperature dependence of the second threshold field at about 45–55 K. The results indicate that the dynamical behavior of the second threshold effects may originate from different mechanisms. We suggest that the highly conducting state at 20–45 K and 55–100 K result from the undamped sliding motion of rigid CDW and current inhomogeneity, respectively. [Copyright &y& Elsevier]

This paper describes the influence of siliceous low-temperature hydrothermal fluid on the elemental concentrations and mineralogical characteristics of the late Permian anthracitic (Ro,max=3.58%) coal seam (No. 30) from the Zhijin Coalfield in western Guizhou Province, SW China. Coal samples were examined using instrumental neutron activation analysis, inductively coupled plasma-mass spectroscopy, inductively coupled plasma-atomic emission spectrometry, X-ray fluorescence, powder X-ray diffraction, scanning electron microscopy equipped with energy-dispersive X-ray, and isotope analysis. The modes of occurrence of elements were determined using a sequential chemical extraction procedure. The studies indicate that the No. 30 coal seam has a very high content of veined quartz (vol. 9.4%), whose isotope values of δ30Si and δ18O are 0.6‰ and 15.4‰, respectively, indicating that the quartz originated from siliceous low-temperature hydrothermal fluid (formation temperature 160–220 °C) rather than detrital material of terrigenous origin or magmatic hydrothermal inputs. Results of scanning electron microscopy equipped with energy-dispersive X-ray and sequential chemical extraction procedure show that the veined quartz is the dominant source of Fe, Cu, U, Pd, Pt and Ir, which are as high as 2.31%, 356, 8, 2.1, 2.43, and 0.006 μg/g in this coal seam, respectively. The studies have also found that elements, such as Fe and Cu are mainly in the veined quartz and they do not occur as sulfides in this coal seam, in sharp contrast to many other coal seams in China. The geochemical and mineralogical anomalies of the coal are attributed to the siliceous low-temperature hydrothermal fluid. [Copyright &y& Elsevier]

Abstract Encapsulating fluorogens into polymeric nanoparticles is proven an effective method to shield the fluorogens from the outer environment and improve the biocompatibility as well. Conventionally, the fluorogens are firstly conjugated to the monomers and then polymerized into macromolecules, where tedious molecular design and synthesis was unavoidable. Herein, we present a facile method to prepare the fluorogen-functionalized polymer, and then use the polymer as build blocks to fabricate nano-probes aiming at cell-imaging. Unlike the conventional ways, we prepared a homopolymer with active esters on the repeating units and used the polymer as matrix to graft fluorogens and hydrophilic groups. Note that the fluorogen and hydrophilic groups selected in our study were tetraphenylethylene (TPE) and polyethylene glycol (PEG), respectively. The resulting amphiphilic random copolymer self-assembled into spherical nanoparticles with size around 225 nm in aqueous solution. With comparable amount of TPE moieties, the polymeric nanoparticles demonstrated much stronger emission than the nanoparticles formed by small molecules of TPE derivatives. The polymeric nanoparticles showed very good stability and biocompatibility, and were employed to label Hela cells and gave high-contrast fluorescent images. We anticipate that the methodology presented in this study might be developed into a general avenue to encapsulating fluorogens into nanoparticles. Graphical abstract Image 1 Highlights • Post-polymerization modification was employed to prepare amphiphilic copolymers. • The copolymer contains TPE and PEG groups on the side chain. • The nanoparticles formed by the copolymers showed strong fluorescent emission. • The nanoparticles were applied to label Hela cells with high-contrast images. [ABSTRACT FROM AUTHOR]

Gas shales with a high gas content were encountered in the Lower Cambrian Lujiaping Formation in the northeast part of the upper Yangtze area, China. In this area, the tectonic condition is complex and the organic matter is over-matured, so conventional oil and gas exploration have not previously been considered. During a recent shale gas exploration, canister-desorbed gas contents of more than 1 m 3 /t were detected from 490 to 825 m depth, with a maximum value of 3.18 m 3 /t at 762 m. Hence to understand the mechanism of preservation of the gas is important. The gas shales have a total organic carbon (TOC) content of between 0.44% and 6.91%, and vitrinite-like macerals reflectance (R o ) between 3.3% and 4.3% with type II kerogen. The porosity of 22 gas shale samples ranges between 0.4% and 2.29%, and their permeability is between 6.9 × 10 − 5 and 3.8 × 10 − 1 mD. To investigate the shale's pore structure and its relation to gas storage behavior, we studied the microscopic mechanism of gas preservation using a combination of pore characterization techniques, including focused ion beam-scanning electron microscope (FIB-SEM) imaging, and comparison of gas sorption and free gas storage capacity. Folding, thrusting and subsequent rapid uplifting movements occurred after most of the dry gas had been originally generated, and the present gas is a mixture originated from the cracking of liquid hydrocarbons at high maturity and kerogen pyrolysis in the early hydrocarbon-generation phase. SEM observations, combined with low temperature gas adsorption and mercury injection capillary pressure analyses, show that pores within the organic matter or the mineral particles in the Lujiaping Shale are rare, while the nanometer-sized pores (1–4 nm) between organic matter and clay mineral particles, especially in cleavage domains, are greatly developed. Thus the gas in these shales is mainly adsorbed gas due to the limited free gas storage space. This is unlike most other shale gas reservoirs, pores within the organic matter and pores between or within mineral particles are dominant. Moreover, the desorbed gas content correlates well with TOC content and the microporous and mesoporous specific surface area determined by low temperature CO 2 and N 2 , respectively, suggesting that the nanometer-sized pores associated with the organic matter make up the fundamental storage space for this shale. The calculations based on FIB-SEM observation showed that the nanometer-sized intergranular pores have large specific surface areas, with their small pore throat diameters resulting in high capillary pressure. These characteristics have contributed to the preservation of shale gas in this complex tectonic area. [ABSTRACT FROM AUTHOR]

Abstract: The modulation effect of transverse current on the switching with hysteresis characteristics of quasi-1D charge-density wave conductor rubidium blue bronze Rb0.3MoO3 single crystals was investigated for the first time. The behavior of the transverse current dependence of second threshold field ( characteristic curves) was obtained at 24 K under the current source driving. The gradually decreases with the increase of transverse current when transverse current exceeds a certain value . The curves become smoother and the switching shows a gentle weakening by the increasing of . Correspondingly, the properties (voltage source driving) with an obvious switching from a low conducting state to a high conducting state were measured under the modulation of transverse current. Gradually, the cannot be distinguished with transverse current increase. The areas of the hysteresis characteristics loop become gently smaller when transverse current increases. It is noted that the transverse currents only induce to decrease when they go up, yet however, hardly affect the back curves of the hysteresis loop. This could explain the effect of the transverse current as not a thermal effect, because the back curves of the hysteresis loop are not identical at different temperatures. [Copyright &y& Elsevier]

Abstract Morphological engineering plays a very important role to the performance of perovskite solar cells. In this study, 3,4-dihydroxybenzhydrazide employes as an additive in the perovskite precursor to control the crystallization kinetics. It is found that the doping of 3,4-dihydroxybenzhydrazide led to increase of grain size and decrease of grain boundaries, both of which facilitate charge transportation and suppress charge recombination within the photoactive layers. Consequently, the power conversion efficiencies of the corresponding perovskite solar cells are significantly enhanced, and a champion power conversion efficiencies of 17.58% with open circuit voltage of 1.06 V, short circuit current density of 21.40 mA cm−2 and fill factor of 79.1% is achieved, which is 21.5% higher than that without 3,4-dihydroxybenzhydrazide (14.47%). Moreover, upon doping the stability of the perovskite solar cells is also improved. We believe that the idea demonstrated in this research can also be applied to other lead-based perovskite systems. Graphical abstract Image 1005 Highlights • DOBD containing Lewis base C O was employed as additive to control the crystallizxation kinetics of perovskite. • The grain size of peroveskite enlarged dramatically with doping of DOBD. • The PCEs of perovskite solar cell with DOBD incrased dramatically and the stability of Pero-SCs was also enhanced. [ABSTRACT FROM AUTHOR]

Abstract: Single crystals of quasi-one-dimensional charge-density-wave conductor blue bronze Tl0.3MoO3 have been grown by electrolytic reduction method using the raw materials Tl2CO3–MoO3 with composition around 1:4.3mol ration. The electrolytic temperature was about 570°C, and electrolytic current was 25mA during the electrolytic process. By this method, the Tl0.3MoO3 single crystals obtained have a relatively large average size and high quality. Platelet crystals with typical dimensions of 7×2×1mm3 were obtained. The crystal structure is monoclinic with space group C2/m. The parameters of the unit cell of the single crystal are as follows: a=18.486(6)Å, b=7.555(2)Å, c=10.032(3)Å and β=118.38(3)°. The C-center symmetry of Tl0.3MoO3 crystal is demonstrated by the selected area electron diffraction (SAED) patterns in the transmission electron microscope (TEM). The full-width at half-maximum (FWHM) of the rocking curve of the Bragg peak of the Tl0.3MoO3 was approximately 0.4°. These are evidences that the single crystal is of high quality. The temperature dependence of the resistivity shows that a metal–semiconductor transition occurs near 181K. [Copyright &y& Elsevier]

[Display omitted] • Natural grids structure of wood was successfully utilized to design alternative TEM grids products. • Wood slice with GO or polyvinyl formal films were applied to fabricate holeless TEM grids. • Nano-materials from 0, 1 to 2 dimensions could be successfully characterized via wooden TEM grids. • Wooden grids show excellent corrosion resistance available for extreme sample conditions. Wood as renewable and earth-abundant biomass material, has attracted much research interest revolving around the utilization of its natural pore structure recently. The highly ordered microtexture of wood has been used to design multitudinous functional products which offer good potential for high value utilization of wood resource. Here, a novel application has been developed by using thin wood slice with transparent grid structure to fabricate TEM grids, which could entirely replace commercially products in TEM observation and even widen their application condition. Wood slice with simple inclusions removal process was used as holey grids directly, and a facile method was employed to uniformly cover graphene oxide/polyvinyl formal films on wood slice skeleton as holeless TEM grids. It has been proved that both the fabricated holey and holeless TEM grids are successfully applied to clearly observing the morphology and structure of nano-materials from zero dimension, one dimension to two dimensions. Meanwhile, it demonstrates wooden TEM grids are feasible in strong corrosive sample preparation condition, while commonly used TEM grids are impracticable. The designed TEM grids substitute material has the obvious superiorities in preparation process, low cost, corrosion resistance, hydrophilicity, environment and biocompatibility. The utilization of thin wood slice for TEM grids products also expanded the application field of wood and is very promising to be commercial products. [ABSTRACT FROM AUTHOR]

In this study, we synthesized an amphiphilic α-cyanostilbene derivative (E -form)-1-(12-(2-(2-(benzo[d]thiazol-2-yl)-2-cyanovinyl)-5-(diethylamino)phenoxy)dodecyl)pyridin-1-ium bromide (denoted by BCPB). As being dissolved in aqueous solution, BCPB shows strong emission of excimers at around 660 nm due to the formation of aggregates. Addition of different amount of CB[7] into the solution leads to the emission shift from 660 nm, firstly to 540 nm and then to 588 nm. The emission shift is attributed to the two-step assembly driven by the concentration of CB[7], and the molar ratios of CB[7]/BCPB (denoted by R m) play a critical role for the shift. As R m ≤ 4, CB[7] mainly interacts with the cationic pyridinium group of BCPB to form BCPB@CB[7] complex. As R m > 4, another CB[7] binds to the diethylamino group at one end of α-cyanostilbene to form BCPB@CB[7] 2 complex. The two-step assembly well explains the emission shift of BCPB. Three distinctly different emissions of an amphiphilic α-cyanostilbene derivative are realized through two-step host-guest assembly driven by concentration of cucurbit[7]uril. Image 1 • An α-cyanostilbene derivative BCPB is synthesized, and the emission properties with existence of CB[7] are investigated. • BCPB showed two-step assembly with CB[7], so the emission shifted from 660 nm, firstly to 540 nm and then to 588 nm. • The two-step assembly was confirmed by mass spectra, 1H NMR and FTIR, and supported by the morphological change. [ABSTRACT FROM AUTHOR]