Improved response time of laser etched polymer optical fiber Bragg grating humidity sensor

The humidity sensor made of polymer optical fiber Bragg grating (POFBG) responds to the water content change in fiber induced by the change of environmental condition. The response time strongly depends on fiber size as the water change is a diffusion process. The ultra short laser pulses have been providing an effective micro fabrication method to achieve spatial localized modification in materials. In this work we used the excimer laser to create different microstructures (slot, D-shape) in POFBG to improve its performance. A significant improvement in the response time has been achieved in a laser etched D-shaped POFBG humidity sensor

Sintering Temperature Induced Evolution of Microstructures and Enhanced Electrochemical Performances: Sol-Gel Derived LiFe(MoO4)2 Microcrystals as a Promising Anode Material for Lithium-Ion Batteries

A facile sol-gel process was used for synthesis of LiFe(MoO4)2 microcrystals. The effects of sintering temperature on the microstructures and electrochemical performances of the as-synthesized samples were systematically investigated through XRD, SEM and electrochemical performance characterization. When sintered at 650°C, the obtained LiFe(MoO4)2 microcrystals show regular shape and uniform size distribution with mean size of 1–2 μm. At the lower temperature (600°C), the obtained LiFe(MoO4)2 microcrystals possess relative inferior crystallinity, irregular morphology and vague grain boundary. At the higher temperatures (680 and 700°C), the obtained LiFe(MoO4)2 microcrystals are larger and thicker particles. The electrochemical results demonstrate that the optimized LiFe(MoO4)2 microcrystals (650°C) can deliver a high discharge specific capacity of 925 mAh g−1 even at a current rate of 1 C (1,050 mA g−1) after 500 cycles. Our work can provide a good guidance for the controllable synthesis of other transition metal NASICON-type electrode materials

Synthesis of a Dual Functional Anti-MDR Tumor Agent PH II-7 with Elucidations of Anti-Tumor Effects and Mechanisms

Multidrug resistance mediated by P-glycoprotein in cancer cells has been a major issue that cripples the efficacy of chemotherapy agents. Aimed for improved efficacy against resistant cancer cells, we designed and synthesized 25 oxindole derivatives based on indirubin by structure-activity relationship analysis. The most potent one was named PH II-7, which was effective against 18 cancer cell lines and 5 resistant cell lines in MTT assay. It also significantly inhibited the resistant xenograft tumor growth in mouse model. In cell cycle assay and apoptosis assay conducted with flow cytometry, PH II-7 induced S phase cell cycle arrest and apoptosis even in resistant cells. Consistently revealed by real-time PCR, it modulates the expression of genes related to the cell cycle and apoptosis in these cells, which may contributes to its efficacy against them. By side-chain modification and FITC-labeling of PH II-7, we were able to show with confocal microscopy that not only it was not pumped by P-glycoprotein, it also attenuated the efflux of Adriamycin by P-glycoprotein in MDR tumor cells. Real-time PCR and western blot analysis showed that PH II-7 down-regulated MDR1 gene via protein kinase C alpha (PKCA) pathway, with c-FOS and c-JUN as possible mediators. Taken together, PH II-7 is a dual-functional compound that features both the cytotoxicity against cancer cells and the inhibitory effect on P-gp mediated drug efflux

MOF-derived Cobalt Sulfide Grown on 3D Graphene Foam as an Efficient Sulfur Host for Long-Life Lithium-Sulfur Batteries

Summary: Lithium-sulfur (Li-S) batteries are an appealing candidate for advanced energy storage systems because of their high theoretical energy density and low cost. However, rapid capacity decay and short cycle life, mainly resulting from polysulfide dissolution, remains a great challenge for practical applications. Herein, we present a metal-organic framework (MOF)-derived Co9S8 array anchored onto a chemical vapor deposition (CVD)-grown three-dimensional graphene foam (Co9S8-3DGF) as an efficient sulfur host for long-life Li-S batteries with good performance. Without polymeric binders, conductive additives, or metallic current collectors, the free-standing Co9S8-3DGF/S cathode achieves a high areal capacity of 10.9 mA hr cm−2 even at a very high sulfur loading (10.4 mg cm−2) and sulfur content (86.9 wt%). These results are attributed to the unique hierarchical nanoarchitecture of Co9S8-3DGF/S. This work is expected to open up a promising direction for the practical viability of high-energy Li-S batteries. : Inorganic Chemistry; Energy Materials; Porous Material Subject Areas: Inorganic Chemistry, Energy Materials, Porous Materia

Construction of Spatial Pattern of Garden Plant Landscape in Urban Waterfront

The spatial pattern of urban waterfront landscape is an important factor affecting the quality of urban culture and improving the recognition of the city. As the core material of urban landscape design, garden plants play a very important role in the construction of spatial pattern of urban waterfront landscape. The spatial pattern of garden plant landscape can be divided into three types: two-dimensional, vertical and special. The two-dimensional spatial pattern focuses on the construction of "meaning and form". The vertical spatial pattern focuses on the construction of "image". The special spatial pattern of garden plants focuses on the construction of "artistic conception". The three types are used to create a spatial pattern of urban waterfront landscape with rich spatial and temporal changes and artistic connotation

Dynamical analysis and optimal harvesting of a stochastic three-species cooperative system with delays and Lévy jumps

Abstract A three-species cooperative system with time delays and Lévy jumps is proposed in this paper. Firstly, by comparison method and inequality techniques, we discuss the stability in mean and extinction of species, and the stochastic permanence of this system. Secondly, by applying asymptotic method, we investigate the stability in distribution of solutions. Thirdly, utilizing ergodic method, we obtain the optimal harvesting policy of this system. Finally, some numerical examples are given to illustrate our main results

Recent advances in Mn-based oxides as anode materials for lithium ion batteries

The development of new electrode materials for lithium-ion batteries (LIBs) is of great interest because available electrode materials may not meet the high-energy demands for electronic devices, especially the demands for good cyclic and rate performance. Mn-based oxides have received substantial attention as promising anode materials for LIBs due to their high theoretical specific capacities, low charge potential vs. Li/Li+, environmental benignity and natural abundance. Herein, the preparation of Mn-based oxide nanomaterials with various nanostructures and chemical compositions along with their applications as negative electrodes for LIBs are reviewed. The review covers MnO, Mn3O4, Mn2O3, MnO2, CoMn2O4, ZnMn2O4 and their carbonaceous composite/oxide supports with different morphologies and compositions. The aim of this review is to provide an in-depth and rational understanding of the relationships among the chemical compositions, morphologies and electrochemical properties of Mn-based anode materials and, to understand how electrochemical performance can be improved using materials engineering strategies. Special attention has been paid to the discussion of challenges in the practical applications of Mn-based oxides in LIB full cells

Hierarchical Ultrathin Layered GO-ZnO@CeO2 Nanohybrids for Highly Efficient Methylene Blue Dye Degradation

Highly efficient interfacial contact between components in nanohybrids is a key to achieving great photocatalytic activity in photocatalysts and degradation of organic model pollutants under visible light irradiation. Herein, we report the synthesis of nano-assembly of graphene oxide, zinc oxide and cerium oxide (GO-ZnO@CeO2) nanohybrids constructed by the hydrothermal method and subsequently annealed at 300 °C for 4 h. The unique graphene oxide sheets, which are anchored with semiconducting materials (ZnO and CeO2 nanoparticles), act with a significant role in realizing sufficient interfacial contact in the new GO-ZnO@CeO2 nanohybrids. Consequently, the nano-assembled structure of GO-ZnO@CeO2 exhibits a greater level (96.66%) of MB dye degradation activity than GO-ZnO nanostructures and CeO2 nanoparticles on their own. This is due to the thin layers of GO-ZnO@CeO2 nanohybrids with interfacial contact, suitable band-gap matching and high surface area, preferred for the improvement of photocatalytic performance. Furthermore, this work offers a facile building and cost-effective construction strategy to synthesize the GO-ZnO@CeO2 nanocatalyst for photocatalytic degradation of organic pollutants with long-term stability and higher efficiency