21 research outputs found

    The dynamics variation of soil moisture of shelterbelts along the Tarim Desert Highway

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    We studied the variation of soil moisture as well as its regularity over the irrigation cycle at shelterbelts along the Tarim Desert Highway at different site types and different planting years. The results show that: (1) There is an obvious temporal variation of soil moisture within a typical irrigation period in shelterbelts along the Tarim Desert Highway, and the soil water storage varied linearly with the number of days after irrigation. Along the direction perpendicular to the soil top, the soil profile can be divided into four layers and each shows different dynamics of soil moisture variation, including the quickly changing layer (0-20 cm), the active layer (20-60 cm), the weakly layer (60-100 cm), and the regulated layer (under 100 cm). (2) Both the soil moisture and soil water content decreased gradually with the number of planting year, while the soil water deficit increased. It indicates that shelterbelts along the Tarim Desert Highway can retain the water accumulated from previous years. (3) The soil water storage of harden sand is the maximum among all types of sites. Specifically, it is about 1.58 times higher than that of longitudinal dune, 1.15 times higher than clay, and 1.43 times higher than flat sand. Its soil water deficit was over 900 mm

    Preparation and Thermoelectric Properties Study of Bipyridine-Containing Polyfluorene Derivative/SWCNT Composites

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    Polymer/inorganic thermoelectric composites have witnessed rapid progress in recent years, but most of the studies have focused on the traditional conducting polymers. The limited structures of traditional conducting polymers restrain the development of organic thermoelectric composites. Herein, we report the preparation and thermoelectric properties of a series of composites films based on SWCNTs and bipyridine-containing polyfluorene derivatives. The value of the power factor around 12 μW m−1 K−2 was achieved for the composite F8bpy/SWCNTs with a mass ratio of 50/50, and the maximum value of 62.3 μW m−1 K−2 was obtained when the mass ratio reached 10/90. Moreover, taking advantage of the bipyridine unit could chelate various kinds of metal ions to form polymer complexes. The enhanced power factor of 87.3 μW m−1 K−2 was obtained for composite F8bpy-Ni/SWCNTs with a mass ratio of 50/50. Finally, the thermoelectric properties of the bipyridine-containing polyfluorene derivative/SWCNT composites were conveniently tuned by chelating with different metal ions

    One-Chip Isolation of Drug-Resistant Acute Myeloid Leukemia Cells with CXCR4-Targeted Magnetic Fluorescent Nanoprobes

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    Drug resistance and relapse lead to high mortality in acute myeloid leukemia, and studies have shown that CXCR4 overexpression is highly correlated with poor prognosis and drug resistance in leukemia cells. Isolation and detection of AML cells with CXCR4 overexpression will be crucial to the treatment of AML. In this paper, magnetic nanoparticles were firstly prepared successfully by high-temperature thermal decomposition method, and then characterized by TEM, VSM and DLS. Subsequently CXCR4-targeted magnetic fluorescent nanoprobes conjugated with antibody 12G5 were constructed by stepwise coupling. In cell experiments, the obtained probes demonstrated excellent targeting efficacy to CXCR4 overexpressed AML cells HL-60. In addition, HL-60 cells labelled with the magnetic probes can be magnetic isolated successfully in one microfluidics chip, with efficiency of 82.92 ± 7.03%. Overall, this method utilizes the superiority of superparamagnetic nanomaterials and microfluidic technology to achieve the enrichment and capture of drug-resistant cells in a microfluidic chip, providing a new idea for the isolation and detective of drug-resistant acute myeloid leukemia cells

    Recent Developments for Flexible Pressure Sensors: A Review

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    Flexible pressure sensors are attracting great interest from researchers and are widely applied in various new electronic equipment because of their distinct characteristics with high flexibility, high sensitivity, and light weight; examples include electronic skin (E-skin) and wearable flexible sensing devices. This review summarizes the research progress of flexible pressure sensors, including three kinds of transduction mechanisms and their respective research developments, and applications in the fields of E-skin and wearable devices. Furthermore, the challenges and development trends of E-skin and wearable flexible sensors are also briefly discussed. Challenges of developing high extensibility, high sensitivity, and flexible multi-function equipment still exist at present. Exploring new sensing mechanisms, seeking new functional materials, and developing novel integration technology of flexible devices will be the key directions in the sensors field in future

    Synthesis and Applications of Silver Nanowires for Transparent Conductive Films

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    Flexible transparent conductive electrodes (TCEs) are widely applied in flexible electronic devices. Among these electrodes, silver (Ag) nanowires (NWs) have gained considerable interests due to their excellent electrical and optical performances. Ag NWs with a one-dimensional nanostructure have unique characteristics from those of bulk Ag. In past 10 years, researchers have proposed various synthesis methods of Ag NWs, such as ultraviolet irradiation, template method, polyol method, etc. These methods are discussed and summarized in this review, and we conclude that the advantages of the polyol method are the most obvious. This review also provides a more comprehensive description of the polyol method for the synthesis of Ag NWs, and the synthetic factors including AgNO3 concentration, addition of other metal salts and polyvinyl pyrrolidone are thoroughly elaborated. Furthermore, several problems in the fabrication of Ag NWs-based TCEs and related devices are reviewed. The prospects for applications of Ag NWs-based TCE in solar cells, electroluminescence, electrochromic devices, flexible energy storage equipment, thin-film heaters and stretchable devices are discussed and summarized in detail

    Pressureā€Temperature Dualā€Parameter Flexible Sensors Based on Conformal Printing of Conducting Polymer PEDOT:PSS on Microstructured Substrate

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    Abstract Flexible sensors play an important role in collecting stimuli information and sending them to a central processing unit or cloud for analysis and decisionā€making. As much information is needed to be collected, the fabrication of multiparameter flexible sensors is becoming increasingly urgent. To this end, conducting polymerā€based composites have been proven as promising materials for developing pressureā€temperature dualā€parameter sensors. However, fabrication of ideal dualā€parameter sensors with fully decoupled pressureā€temperature readings, good sensitivity, and a simple preparation process remain challenges. Here, a strategy of fabricating a pressureā€temperature dualā€parameter sensor based on conformal printing of conducting polymer poly(3,4ā€ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) on the surface of microstructured polydimethylsiloxane (PDMS) substrate is demonstrated. It is found that secondary doped PEDOT:PSS provides temperatureā€independent conductivity. Combined with the seaā€island microstructured PDMS substrate, a screenā€printed flexible sensor demonstrates fully decoupled pressureā€temperature reading ability, competitive sensitivity, and good stability. The excellent sensing properties of the devices, with a maximum pressure sensitivity of 134.25 kPaāˆ’1 and linear response region over 300Ā kPa as well as highly sensitive temperature sensing for finger touch, together with their unique advantages of lowā€cost and largeā€area fabrication, make the printed flexible dualā€parameter sensors promising applications in electricā€skin (eā€skin), humanā€machine interaction, and robotics

    Erratum to ā€œPickering emulsions stabilized by whey protein nanoparticles prepared by thermal cross-linkingā€

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    The publisher regrets that minor errors occurred in the above paper. The errors relate to the Fig. 1C. Below is the correct Fig. 1C.</p

    Pickering emulsions stabilized by whey protein nanoparticles prepared by thermal cross-linking

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    A Pickering (o/w) emulsion was formed and stabilized by whey protein isolate nanoparticles (WPI NPs). Those WPI NPs were prepared by thermal cross-linking of denatured WPI proteins within w/o emulsion droplets at 80. Ā°C for 15. min. During heating of w/o emulsions containing 10% (w/v) WPI proteins in the water phase, the emulsions displayed turbid-transparent-turbid phase transitions, which is ascribed to the change in the size of the protein-containing water droplets caused by thermal cross-linking between denatured protein molecules. The transparent stage indicated the formation of WPI NPs. WPI NPs of different sizes were obtained by varying the mixing speed. WPI NPs of 200-500. nm were selected to prepare o/w Pickering emulsions because of their good stability against coalescence. By Confocal Laser Scanning Microscopy, it was observed that WPI NPs were closely packed and distributed at the surface of the emulsion droplets. By measuring water contact angles of WPI NPs films, it was found that under most conditions WPI NPs present good partial wetting properties, but that at the isoelectric point (p. I) and high ionic strength the particles become more hydrophobic, resulting in less stable Pickering emulsion. Thus, at pH above and below the p. I of WPI NPs and low to moderate ionic strengths (1-10. mM), and with a WPI NPs concentration of 2% (w/v), a stable Pickering emulsion can be obtained. The results may provide useful information for applications of WPI NPs in environmentally friendly and food grade applications, notably in food, pharmaceutical and cosmetic products
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