Search

Ambient humidity plays an important role in the fields of industrial and agricultural production, food and drug storage, climate monitoring, and maintenance of precision instruments. To sense and control humidity, humidity-responsive actuators that mimick humidity responsive behavior existing in nature, have attracted intense attention. The most common and important class of humidity actuators is active bilayer structures. However, such bilayer structures generally show weak interfacial adhesion, tending to delaminate during frequent bending and restoration cycles. In this work, to address this problem, a novel monolayer humidity-driven actuator with no adhesive issue is developed by integrating the swellable metal–organic frameworks (MIL-88A) into thermoplastic polyurethane films. The proposed actuators display excellent humidity response that under the conditions of relative humidity simulated with saturated salt solution, the MIL-88A/polyurethane composite films show good self-folding response and stability for recycling use. In addition, a deep insight into the self-folding of the composite films is also provided and a new response mechanism is proposed. In this case, the results show that both the preparation method and response properties of the humidity actuators are improved. Therefore, it suggests a new promising way to develop and design flexible humidity actuators.

Three new perovskite-like hybrid iodobismuthates with two quaternary ammonium cations, namely (BnNEt3)3(Bi2I9) (1) (BnNEt3)4(Bi4I16) (2) and (n-Bu4N)2n(Bi4I14)n (3) (Bn = benzyl, n-Bu = n-butyl), have been synthesized by reacting BiI3 with the quaternary ammonium iodide in molar ratio 2:3 (1), 1:1(2), and 2:1 (3), respectively. All hybrids were characterized by elemental analysis, X-ray diffraction and UV–Vis spectroscopic analysis. Single-crystal X-ray diffraction revealed that hybrids 1 and 2 are di-nuclear and tetra-nuclear cluster structures respectively, while 3 is a polymeric chain structure based on a (Bi4I14) tetra-nuclear cluster unit. Their optical band-gaps have been determined as 2.19 eV(1), 2.16 eV(2), 2.02 eV(3), respectively. The optical band gaps exhibit a structure-related decrease from 1 to 3, in agreement with their color changes and the density functional theory (DFT) calculation results. The DFT calculations also reveal that there is a inversely proportional relationship between the optical Eg and the aggregation degree of the BiI6 octahedra in the hybrid iodobismuthate clusters.

Silver microparticles have inspired much research interest due to their enhanced properties for use in optical, electric, catalytic, and magnetic applications. One such use is as electrically conductive filler for printed electronics. A manufacturing approach has been developed to prepare low-curing-temperature silver pastes. Firstly, silver flakes were synthesized directly by a one-step aqueous-phase reduction reaction, using silver nitrate as silver salt precursor and iron(II) sulfate heptahydrate as reducing agent. Various silver flake samples were synthesized by controlling experimental parameters such as the reaction temperature, surfactant concentration, and reducing agent concentration. The obtained silver powders were characterized by x-ray diffraction analysis, scanning electron microscopy, and dynamic light scattering measurements. The results revealed that the morphology of the silver powders was a plate-like structure with diameter of 1 μm to 1.5 μm and thickness of 30 nm. The prepared silver flakes were then used directly without ball milling to prepare low-curing-temperature silver pastes. The bulk resistivity of a line screen-printed using silver paste containing 48 wt.% (34 ± 5 vol.%) silver flakes and cured at 140°C for 30 min in air was about (1.773 ± 0.118) × 10−6 Ω m. More importantly, the prepared screen-printed patterns exhibited excellent durability in terms of peel strength and folding endurance.

Land use and land cover (LULC) play a significant role in carbon regulation. South-China accounts for ~65% of China’s carbon sink. In Xishuangbanna (South-China), rubber is expanding rapidly creating an urgent need to understand and monitor LULC change and how spatial variation affects carbon storage (CS). This is vital for the formation and implementation of better land use management practices. We studied LULC changes of 22-year period; addressing how these changes have affected the CS. We quantified LULC changes between1988 and 2010 using remote sensing methods and calculated CS changes using InvEST. Results showed that between 1988 and 2010, the rate of deforestation accelerated to 203.2 km 2 y −1 and ~23% of forest were lost. Conversion of natural forest to rubber was responsible for 78% of this deforestation. Rubber expansion rate was 153.4 km 2 y −1 . Changes to LULC drove a temporal CS reduction 0.223 Tg C/km 2 . Local stakeholders have strong economic interest in converting land to more profitable plantations. Government efforts is required to control land conversion through new policies and incentives to retain natural forest. Assessment of specific potential land use change will be required to avoid promoting the conversion of high carbon storage land uses to low carbon storage land uses.

Lactarius subg. Russularia is a large group of milkcaps occurring almost worldwide and dominant in many ecosystems. In this study we focus on new diversity, evolutionary relationships, divergence time, and origin of the subgenus. Six conifer symbionts are described as new to science: Lactarius atrii, L. aurantionitidus, L. dombangensis, L. flavigalactus, L. lachungensis, and L. sikkimensis. Species delimitation is assessed based on the concordance between morphological characteristics and an ITS phylogeny. Infrageneric relationships were studied using a phylogeny constructed from concatenated ITS-rpb2 data using Maximum Likelihood and Bayesian inference. Results show that species in this subgenus do not cluster together according to their geographic origin. Intercontinental sister relationships between Europe/Asia/North America are common but actual conspecificity is rare. This result suggests that allopatric speciation has played an important role within this subgenus. Only few morphological characteristics tend to be phylogenetically informative, with the most important being presence or absence of true cystidia and the pileipellis structure. Two datasets were generated in order to estimate the age of L. subg. Russularia. The results suggest the origin of L. subg. Russularia to be in the Mid Miocene period.

Four new three-coordinate cuprous complexes with a CuN2P core, 1-QBO, 2-Phen, 3-MePBO, 4-QBI, were designed and synthesized by utilizing a steric hindrance of phosphine ligand o-Anisyl3P [QBO = 2-(2′-quinolyl)benzoxazole, Phen = 1,10-Phenanthroline, MePBO = 5-methyl-2-(2′-pyridyl)-benzoxazole, QBI = 2-(2′-quinolyl)benzimidazole, o-Anisyl3P = tri(2-methoxyphenyl)-phosphine]. As a counterpart to 1-QBO, a four-coordinate complex 5-QBOP2 has also been synthesized with a CuN2P2 core. All complexes were characterized by single-crystal X-ray diffraction, spectroscopic analysis (IR, UV–Vis), elemental analysis, and photoluminescence study. Single-crystal X-ray diffraction revealed that complexes 1–4 all adopt trigonal CuN2P coordination geometry with one phosphine and one diimine ligand. Their UV–Vis absorption spectra exhibit concentration dependences of absorption edge shift. Time-dependent density functional theory (TD-DFT) calculations reveal that their S1 states and the peak transition states can be mainly assigned as ligand–ligand & metal–ligand charge transfer (L′LCT + MLCT) and intra-ligand charge transfer (ILCT) states, respectively. It is noteworthy that all three-coordinate complexes 1–4 do not display obvious photoluminescence (PL), whereas the PL of four-coordinate complex 5 is turned on by an extra coordination of a phosphine ligand to 1. This PL complex has also been synthesized and characterized as 5-QBOP2 from 1-QBO. This model of three-coordinate to four-coordinate change with PL turn-on behavior could be used for sensing volatile organic compounds (VOCs).

Laser scanning is widely used in on-line industrial 3D inspection, cultural heritage conservation and reverse engineering. However, in the traditional laser scanning, the most widely-used approach is based on the projection of a single directional laser stripe over an object. Because the width of the laser stripe is physically difficult to compress enough to be fine at the edge of the object, the traditional measurement method is not accurate for edge measurements. This paper proposes an edge sensitive 3D measurement system which is fast and accurate, using two directional laser stripes scanning with a laser projector. Scanning metal edge steps and complex surface edge with this system only require a single scanning to perform 3D reconstruction. So this scanning method has the advantages of high efficiency, high speed and edges with high precision.

The Fringe Projection System (FPS) and the Laser Stripe Projection System (LSPS) both have the limitations in 3D measurements. For a shiny and diffusive surface with complex shape, neither of the systems could manage it individually at a low cost. To overcome these difficulties, we propose a method combining these two ways of projections together using a laser projector, which could project fringe patterns and scanning-laser-stripes both. In this method, we obtain two disparity maps and two quality maps by FPS and LSPS, respectively. Then combine two disparity maps together by quality maps and reconstruct the surface of the object with the combined disparity map. Real experiments are carried out to verify the proposed method and to evaluate the system performance. The plain, the colored and the metal plastic mixed objects are all reconstructed successfully in the proposed method.

A series of strongly phosphorescent copper(I) halide complexes, namely [Cu(μ-X)POP]2 (X = Cl (1), Br (2), I (3), Br0.5Cl0.5 (4), POP = bis[2-(diphenylphosphino)phenyl]ether), have been synthesized by reacting CuX with the diphosphine ligand in 1:1 molar ratio. All complexes were characterized by spectroscopic analysis (IR, UV–Vis), elemental analysis, and photoluminescence study. Single-crystal X-ray diffraction revealed that complex 2 is a dinuclear structure which is constructed by two μ-X bridges and two POP ligands as μ2 bridges. Other complexes were determined as isologues of complex 2 by powder X-ray diffraction and elemental analysis. All complexes exhibit intense blue-green phosphorescence with a lifetime of ~1 μs in the solid state. The halogen-mixed complex presents a lightly change in the luminescence comparing to that of parent complexes. The excited states of all complexes have been assigned as halide-to-ligand charge transfer state mixed metal-to-ligand charge transfer character based on the time-dependent density functional theory calculations. All complexes are thermally stable according to thermogravimetric analysis so that they are suitable for applying in luminescent devices.

A flexible polycarboxyl ligand of tetrahydrofuran-2,3,4,5-tetracarboxylic acid (H4THFTCA) and a common rigid aromatic ligand of 1,10-phenanthroline (phen) have been successfully co-assembled with Cu(NO3)2·3H2O to give out a novel 3D supramolecular metal–organic framework (MOF) compound, [Cu2(THFTCA)(phen)(H2O)2·CH3CH2OH·3H2O] n (1), by a solution self-assembly process. Compound 1 has been characterized as a 2D layered coordination polymer constructed by THFTCA4− and Cu2+ ions, and the layer present a novel (3.52)(32.53.64.7) topological network. Interestingly, the layers are fused each other via strong π–π stacking interactions among adjacent ligands of the terminal phen, so that a 3D supramolecular MOF with 1D rhomboidal tunnels array is formed. The thermogravimetric analysis and corresponding powder X-ray diffraction analysis have revealed that the tunnels structure of 1 could be retained after all guest molecules are removed, and the framework could resist the collapse even heating up to 210 °C. An opinion has also been proposed that the larger accessible volume of the guests means the larger stress on the backbone of the MOF after the guests are removed, and the stress is harmful to the stability of the supramolecular porous structure. Finally, the application properties based on the porous structure have also been primarily evaluated.

s During the course of reinvestigating the reactions of iodate anion and lanthanide cations under different conditions, the single-crystal structure of Eu(IO 3 ) 3 (H 2 O)·H 2 O ( 1 ) and a series of corresponding nanoplate materials were obtained. X-ray single-crystal diffraction reveals that 1 is characterized as a two-dimensional inorganic layered structure with an unprecedented binodal (3, 5)-connected net of (3·4·5)(3 2 ·4 2 ·5·6 3 ·7 2 ) topology. A simple solution reaction method has also been founded for synthesizing corresponding Ln(IO 3 ) 3 (H 2 O)·H 2 O (Ln = Nd, Eu, Gd, Tb, Dy) nanoplate materials. PXRD measurements have shown that the size of the particles increases along with the raise of the adopted synthesis temperature. Their thermogravimetric analyses (TGA) and luminescence properties have also been discussed. The strong red/yellow emission for materials of Eu III /Tb III was observed, respectively.

The LaBr3:Ce crystal is difficult to grow although it has very excellent scintillation properties. In this paper, the LaBr3:Ce crystals have been grown by the self-seeding Bridgman technique, and the ⌀ 38 mm × 50 mm LaBr3:Ce single crystal ingot has been achieved. It is found that the orientation of the crystal growth has a close relationship with the lowering velocity and the quartz ampule shape. The 1 mm/h lowering velocity is very helpful for the [001] direction to dominate the crystal growth under the certain ampule shape, thus avoiding the crystal crack effectively, and the 0.5 mm/h lowering velocity is helpful for the [100] direction to dominate the crystal growth under the same ampule shape. On this basis, the mechanism of the nuclei competition is discussed. The UV luminescence and the X-ray excited emission spectra of the LaBr3:Ce crystal have also been investigated.