To develop a finescale dataset for the purpose of analyzing historical climatic change over the Tibet Plateau (TP), a high-resolution regional climate simulation for 1979–2011 was conducted using the ...Weather Research and Forecasting (WRF) Model driven by the ERA-Interim (ERA-Int). This work evaluates the high-resolution (30 km) WRF simulation in terms of annual variation, spatial structure, and 33-yr temporal trends of surface air temperature (Tair) and precipitation (Prec) over the TP, with reference to station observations. Another focus is on the examination of the height–temperature relationship. Inheriting from its forcing, the WRF simulation presents an apparent cold bias in the TP. The cold bias is largely reduced by a lapse rate correction of the simulated surface air temperature with help of the station and model elevations. ERA-Int presents the same sign of Tair and Prec trends as the observations, but with smaller magnitude, especially in the dry season. Compared to its forcing, the WRF simulation improves the simulation of the annual cycles and temporal trends of Tair and Prec in the wet season. In the dry season, however, there is hardly any improvement. The observed Tair presents a downward linear trend in the lapse rate. This feature is examined in the WRF simulation in comparison to ERA-Int. The WRF simulation captures the observed lapse rate and its temporal trend better than ERA-Int. The decreasing lapse rate over time confirms that Tair change in the TP is elevation dependent.
The discovery of the aggregation-induced emission (AIE) phenomenon in the early 2000s not only has overcome persistent challenges caused by traditional aggregation-caused quenching (ACQ), but also ...has brought about new opportunities for the development of useful functional molecules. Through the years, AIE luminogens (AIEgens) have been widely studied for applications in the areas of biomedical and biological sensing, chemosensing, optoelectronics, and stimuli responsive materials. Particularly in the application of chemosensing, a myriad of novel AIE-based sensors has been developed to detect different neutral molecular, cationic and anionic species, with a rapid detection time, high sensitivity and high selectivity by monitoring fluorescence changes. This review thus summarises the recent development of AIE-based chemosensors for the detection of anionic species, including halides and halide-containing anions, cyanides, and sulphur-, phosphorus- and nitrogen- containing anions, as well as a few other anionic species, such as citrate, lactate and anionic surfactants.
Mg–Si alloy was investigated for biomedical application due to the biological function of Si in the human body. However, Mg–Si alloy showed a low ductility due to the presence of coarse Mg
2Si. Ca ...and Zn elements were used to refine and modify the morphology of Mg
2Si in order to improve the corrosion resistance and the mechanical properties. The cell toxicity of Mg, Zn and Ca metals was assessed by an MTT test. The test results indicated that increasing the concentrations of Mg, Zn and Ca ions did not cause cell toxicity, which showed that the release of these three elements would not lead to cell toxicity. Then, microstructure, mechanical properties and bio-corrosion properties of as-cast Mg–Si(–Ca, Zn) alloys were investigated by optical microscopy, scanning electronic microscopy, mechanical properties testing and electrochemical measurement. Ca element can slightly refine the grain size and the morphology Mg
2Si phase in Mg–Si alloy. The bio-corrosion resistance of Mg–Si alloys was improved by the addition of Ca due to the reduction and refinement of Mg
2Si phase; however, no improvement was observed in the strength and elongation. The addition of 1.6% Zn to Mg–0.6Si can modify obviously the morphology of Mg
2Si phase from course eutectic structure to a small dot or short bar shape. As a result, tensile strength, elongation and bio-corrosion resistance were all improved significantly; especially, the elongation improved by 115.7%. It was concluded that Zn element was one of the best alloying elements of Mg–Si alloy for biomedical application.
This paper examines how exchange rate shocks affect intra-industry labor reallocation across firms. Using comprehensive Chinese firm-level data, we examine the employment response to exchange rates ...of firms that are heterogeneous along two dimensions: external orientation and trading partner distribution. Firm-specific effective exchange rates are constructed to accurately measure exchange rate shocks pertinent to individual firms. We find that exchange rate movements induce significant labor reallocation across firms with different degrees of external orientation and with different trading partners. Trading partner distribution is as important as external orientation in explaining firms' heterogeneous employment response to exchange rates. Compared with effective exchange rate measures at more aggregate levels, using firm-specific effective exchange rates generates estimation results more consistent with theory and substantially increases the estimated impact of exchange rates on intra-industry job reallocation.
The effects of the evolution of the lamellar alpha microstructure on the impact toughness of Ti-17 alloy are investigated. For this purpose, the beta-processed material is isothermally forged at ...820°C and subsequently heat treated using the combination of solid solution and aging treatment. Then the impact tests are carried out at room temperature. The corresponding microstructure and fracture surface are examined by scanning electron microscope (SEM). Microstructural observations reveal that globularization behavior is the main feature of microstructure evolution and the globularization fraction increases with the increasing of prestrain. However, globularization behavior has a negative influence on the impact toughness of Ti-17 alloy. In this work, the impact toughness have been obtained in the range of 29–55J/cm2 via varying globularization fraction of alpha phase. A linear relationship between the impact toughness and globularization fraction can be observed though the quantitative analysis. The linear equation is expressed as A=−0.3232f+59.885. The two major reasons can be used to explain the effect of globularization fraction on the impact property of Ti-17 alloy. One explanation is that the lamellar structure can provide excellent interfacial strengthening effect, which can improve the toughness of material, and makes it not easy to fracture. On the other hand, the fracture surface of specimen with the lamellar structure has larger amplitude of ups and downs. A long crack path length will be generated during fracture process. By contrast, the fracture of specimen with the equiaxed structure presents more flat surface and shorter crack path.
Compared to traditional methods, three/four-dimensional (3D/4D) printing technologies allow rapid prototyping and mass customization, which are ideal for preparing nano/microstructures of soft ...polymer materials. Poly (lactic acid) (PLA) is a biopolymer material widely used in additive manufacturing (AM) because of its biocompatibility and biodegradability. Unfortunately, owing to its intrinsically poor nucleation ability, a PLA product is usually in an amorphous state after industrial processing, leading to some undesirable properties such as a barrier property and low thermal resistance. Crystallization mediation offers a most practical way to improve the properties of PLA products. Herein, we summarize and discuss 3D/4D printing technologies in the processing of PLA nano/microstructures, focusing on crystallization principles and practical applications including bio-inspired structures, flexible electronics and biomedical engineering mainly reported in the last five years. Moreover, the challenges and prospects of 3D/4D printing technologies in the fabrication of high-performance PLA materials nano/microstructures will also be discussed.
Nanotechnology has been materialized as a proficient technology for the development of anticancer nanoparticles all the way through an environment-friendly approach. Conventionally, nanoparticles ...have been assembled by dissimilar methods, but regrettably rely on the negative impact on the natural environment. Amalgamation of nanoparticles by means of plant extract is alternate conservative methods. Scutellaria barbata species was used majorly as food or as medicines against various diseases, and extensive research was conducted for their therapeutic properties. The present research was mainly focused on the synthesis of gold nanoparticles from the Scutellaria barbata by green route method and evaluation of its anticancer activity against pancreatic cancer cell lines (PANC-1). The gold nanoparticles have been characterized by UV-visible spectroscopy, TEM, SAED, AFM, and FTIR analysis. The synthesized gold nanoparticles (AuNPs) possessed effective anticancer activity against pancreatic cancer cell lines (PANC-1). Hence, further research on this plant may lead to the development of novel anticancer drugs which can be used to combat pancreatic cancer.
Organic materials have gained considerable attention for electrochromic (EC) applications owing to improved EC performance and good processability. As a class of well-recognized organic EC materials, ...viologens have received persistent attention due to the structural versatility and property tunability, and are major active EC components for most of the marketed EC devices. Over the past two decades, extensive efforts have been made to design and synthesize different types of viologen-based materials with enhanced EC properties. This review summarizes chemical structures, preparation and EC properties of various latest viologen-based electrochromes, including small viologen derivatives, main-chain viologen-based polymers, conjugated polymers with viologen side-chains and viologen-based organic/inorganic composites. The performance enhancement mechanisms are concisely discussed. The current marketed viologens-based electrochromic devices (ECDs) are briefly introduced and an outlook on the challenges and future exploration directions for viologen-based materials and their ECDs are also proposed.
Recent progress in the currently available methods of producing black phosphorus bulk and phosphorene are presented. The effective passivation approaches toward improving the air stability of ...phosphorene are also discussed. Furthermore, the research efforts on the phosphorene and phosphorene‐based materials for potential applications in lithium ion batteries, sodium ion batteries, and thermoelectric devices are summarized and highlighted. Finally, the outlook including challenges and opportunities in these research fields are discussed.
Phosphorene and phosphorene‐based materials receive extensive attention for potential applications in energy storage and conversion devices. In this Review, the state‐of‐the‐art progress of phosphorene and phosphorene‐based materials for lithium ion batteries, sodium ion batteries, thermoelectric devices, and other energy storage devices are presented.
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