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A study of polymer photonic crystal fiber (PCF) sensor coated with smart composite materials for measurements of refractive index of analyte is presented in this paper. The proposed sensor combines the characteristics of polymer P...
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A study of polymer photonic crystal fiber (PCF) sensor coated with smart composite materials for measurements of refractive index of analyte is presented in this paper. The proposed sensor combines the characteristics of polymer PCF and composite material, which can make the confinement loss lower than the silica PCF duo to the double interaction of the polymer and silver film. The results obtained in this study demonstrate that polymer PCF sensors coated with composite material and with the polymer PCF's advantages, the sensor's feasibility can be improved further and it can be applied in a broad field, especially in biosensing platforms.
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A hollow-core photonic crystal fiber (HC-PCF)-based gas sensor is proposed and numerically investigated through the finite element method. To obtain higher relative sensitivity coefficient γ and the better sensing properties of t...
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A hollow-core photonic crystal fiber (HC-PCF)-based gas sensor is proposed and numerically investigated through the finite element method. To obtain higher relative sensitivity coefficient γ and the better sensing properties of the gas sensor, the floriated structure of the central hole of HC-PCF is optimized. Numerical investigation shows that γ is high and relatively stable to changes of the diameter of air holes in a wide range of wavelength of 1.5-1.7μm, which is very beneficial for sensor fabrication. A lower confinement loss and the flatness are also exhibited with the HC-PCF. And the highest γ of 0.9998 of the floriated structure of the central hole can be obtained than the circular ones of 0.9435 at the wavelength of 1.56μm.
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It is introduced in this paper employing electromagnetic technique to detect and to locate leakage in cofferdams of a hydropower station construction recently. After fulfillment of high-pressure grouting walls, serious leakage was...
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It is introduced in this paper employing electromagnetic technique to detect and to locate leakage in cofferdams of a hydropower station construction recently. After fulfillment of high-pressure grouting walls, serious leakage was found in both upstream and downstream cofferdams. In order to locate the correct leakage position in the high-pressure grouting walls and foundation, Type GDP-32II Instrument based on transient (time domain) electromagnetic technique and EM34-3 Ground Conductivity Meter based on frequency domain electromagnetic technique were employed. The detecting results were satisfied and were validated by drilling and underwater TV. The principle of the instruments and detecting techniques are also introduced here.
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Laser shock processing (LSP) is a surface hardening technology by using plasma shock waves, which can improve the mechanical properties of material and extend the service life significantly. This work introduced the mechanism of L...
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Laser shock processing (LSP) is a surface hardening technology by using plasma shock waves, which can improve the mechanical properties of material and extend the service life significantly. This work introduced the mechanism of LSP briefly, the analysis of the effect of LSP on the surface morphology, microstructure of material and its related laws are summarized with the aspect from aluminum alloy, titanium alloy and superalloy. The results show that the strong plastic deformation would be appeared in the near-surface of material due to the laser-generated stress effect, resulting the change of surface roughness and the microstructure evolution. At the same time, high-density dislocation walls, dislocation tangles and mechanical twins are generated on the surface, which are accompanied by changes in grain refinement and increased grain boundaries, thereby significantly improve the mechanical properties of material. The convex structure can be found on different material surfaces after LSP, which is micro-scale reverse deformation caused by the free plastic flow of materials under laser shock. And the high pressure of shock waves can lead to destructive dimples on the material surface, and affect its service performance. Aiming at the characteristics of different material, this work comprehensively compares the differences in the surface morphology and microstructure changes of the alloys caused by LSP, and makes a detailed analysis and discussion. This work is helpful for researchers to further understand the high strain rate dynamic plastic deformation mechanism of material treated by LSP, and promote the development of LSP.
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摘要 :
Laser shock processing (LSP) is a surface hardening technology by using plasma shock waves, which can improve the mechanical properties of material and extend the service life significantly. This work introduced the mechanism of L...
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Laser shock processing (LSP) is a surface hardening technology by using plasma shock waves, which can improve the mechanical properties of material and extend the service life significantly. This work introduced the mechanism of LSP briefly, the analysis of the effect of LSP on the surface morphology, microstructure of material and its related laws are summarized with the aspect from aluminum alloy, titanium alloy and superalloy. The results show that the strong plastic deformation would be appeared in the near-surface of material due to the laser-generated stress effect, resulting the change of surface roughness and the microstructure evolution. At the same time, high-density dislocation walls, dislocation tangles and mechanical twins are generated on the surface, which are accompanied by changes in grain refinement and increased grain boundaries, thereby significantly improve the mechanical properties of material. The convex structure can be found on different material surfaces after LSP, which is micro-scale reverse deformation caused by the free plastic flow of materials under laser shock. And the high pressure of shock waves can lead to destructive dimples on the material surface, and affect its service performance. Aiming at the characteristics of different material, this work comprehensively compares the differences in the surface morphology and microstructure changes of the alloys caused by LSP, and makes a detailed analysis and discussion. This work is helpful for researchers to further understand the high strain rate dynamic plastic deformation mechanism of material treated by LSP, and promote the development of LSP.
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Battlefield situational awareness is the core condition that determines the success or failure of the battlefield, and it is also an important application direction of photodetectors. The rapid development of AI technology in rece...
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Battlefield situational awareness is the core condition that determines the success or failure of the battlefield, and it is also an important application direction of photodetectors. The rapid development of AI technology in recent years is about to cause major changes in future wars. The new AI battlefield will also put forward new urgent needs for situational awareness. This article summarizes the current main modes of collaborative detection of battlefield situation awareness and its research status, including radar / infrared composite detection, multi-source data fusion of radar / infrared detection, cooperative target recognition, target tracking, etc. On this basis, combined with the current development trend of the intelligence level of the main battlefield equipment, we get the development needs of future intelligent battlefield situational awareness for new types of collaborative detection, including requirements for its style, angle, speed, and detection targets of distributed collaborative detection. Based on this, the key development directions and core issues to be solved for intelligent battlefield situational awareness in the future are proposed.
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This article summarizes the reports and researches on detection system of STSS published in domestic and foreign literature, summarizes the development process of STSS detection system from a single geostationary orbit to a combin...
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This article summarizes the reports and researches on detection system of STSS published in domestic and foreign literature, summarizes the development process of STSS detection system from a single geostationary orbit to a combined large elliptical orbit, then to the development process of the high-track network and the low-track network cooperate with each other. It also summarizes the development process of infrared detectors from single-band to multi-band, from line scan with less detection pixels to line scan with more detection pixels and large-area staring array The application scenarios, overall scheme, and overall parameters of the STSS detection system are sorted out, and the core technical indicators are analyzed for the overall parameters. From the perspective of the development process of the US early warning satellite system and the technical characteristics of the space-based infrared system, US early warning satellite technology is of great significance to research on US defense programs, equipment, and system capabilities.
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摘要 :
This article summarizes the reports and researches on detection system of STSS published in domestic and foreign literature, summarizes the development process of STSS detection system from a single geostationary orbit to a combin...
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This article summarizes the reports and researches on detection system of STSS published in domestic and foreign literature, summarizes the development process of STSS detection system from a single geostationary orbit to a combined large elliptical orbit, then to the development process of the high-track network and the low-track network cooperate with each other. It also summarizes the development process of infrared detectors from single-band to multi-band, from line scan with less detection pixels to line scan with more detection pixels and large-area staring array The application scenarios, overall scheme, and overall parameters of the STSS detection system are sorted out, and the core technical indicators are analyzed for the overall parameters. From the perspective of the development process of the US early warning satellite system and the technical characteristics of the space-based infrared system, US early warning satellite technology is of great significance to research on US defense programs, equipment, and system capabilities.
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Non-viral vector has been widely used to deliver siRNA and pDNA. MicroRNA (miRNA) was a single-stranded RNA and unstable in vivo. The aim of this work was to investigate PEG grafted chitosan as a potential non-viral vector for miR...
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Non-viral vector has been widely used to deliver siRNA and pDNA. MicroRNA (miRNA) was a single-stranded RNA and unstable in vivo. The aim of this work was to investigate PEG grafted chitosan as a potential non-viral vector for miRNA delivery. In our study, chitosan was modified with mPEG and nanoparticles (NPs) were fabricated by ionic gelation method. The degree of substitution (DS) of mPEG moiety was 6.12%. The particle size and zeta potential were 167.6±4.5 nm and +23.5±0.4 mV, respectively. Gel retardation assay indicated that hsa-miR-15a was encapsulated completely by mPEG-g-Chitosan. NPs protected miRNA from nucleases degradation. Cytotoxicity studies indicated that mPEG-g-CS polymer was a safe carrier with low cytotoxicity compared with PEI and Hiperfect Transfection Reagent. The result of in vitro experiment showed that the fluorescence encapsulated in NPs was accumulated in the cells and the cellular uptake efficiency in vitro was 5.98±0.95% after 48 h incubation, and it was increased about 2.31±0.25% and 4.45±0.25% when compared with the free miR-15a group and blank NPs respectively. The in vitro cellular uptake efficiency of NPs encapsulated has-miRNA was increasing from 1.87±0.15% to 45.27±3.67% as the hsa-miR-15a concentration was increasing from 36.25 nM to 580 nM. These data suggest that the PEG grafted chitosan NPs are efficient vector for miRNA delivery.
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摘要 :
Non-viral vector has been widely used to deliver siRNA and pDNA. MicroRNA (miRNA) was a single-stranded RNA and unstable in vivo. The aim of this work was to investigate PEG grafted chitosan as a potential non-viral vector for miR...
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Non-viral vector has been widely used to deliver siRNA and pDNA. MicroRNA (miRNA) was a single-stranded RNA and unstable in vivo. The aim of this work was to investigate PEG grafted chitosan as a potential non-viral vector for miRNA delivery. In our study, chitosan was modified with mPEG and nanoparticles (NPs) were fabricated by ionic gelation method. The degree of substitution (DS) of mPEG moiety was 6.12%. The particle size and zeta potential were 167.6±4.5 nm and +23.5±0.4 mV, respectively. Gel retardation assay indicated that hsa-miR-15a was encapsulated completely by mPEG-g-Chitosan. NPs protected miRNA from nucleases degradation. Cytotoxicity studies indicated that mPEG-g-CS polymer was a safe carrier with low cytotoxicity compared with PEI and Hiperfect Transfection Reagent. The result of in vitro experiment showed that the fluorescence encapsulated in NPs was accumulated in the cells and the cellular uptake efficiency in vitro was 5.98±0.95% after 48 h incubation, and it was increased about 2.31±0.25% and 4.45±0.25% when compared with the free miR-15a group and blank NPs respectively. The in vitro cellular uptake efficiency of NPs encapsulated has-miRNA was increasing from 1.87±0.15% to 45.27±3.67% as the hsa-miR-15a concentration was increasing from 36.25 nM to 580 nM. These data suggest that the PEG grafted chitosan NPs are efficient vector for miRNA delivery.
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