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Circularly Polarized Wideband Uniplanar Crossed-Dipole Antenna With Folded Striplines and Rectangular Stubs
No full textA circularly polarized (CP) wideband uniplanar crossed-dipole antenna is presented in this paper. The antenna constitutes a pair of identical crossed-dipole arms printed on the same plane of a dielectric substrate. Each crossed-dipole component is a pair of thin dipole arms that are perpendicular to each other and connected with a folded stripline for generating CP radiations. A pair of thin rectangular stubs are introduced on one dipole arm at the center of the antenna to improve impedance-matching bandwidth. Another set of rectangular stubs is attached at the sides of the dipole arms to broaden the axial ratio (AR) bandwidth. The antenna in free space is excited via a coaxial probe with a balun. It generates two adjacent AR bands that are merged into a wide AR bandwidth with bidirectional radiation patterns. Full-wave electromagnetic simulations are performed in the design process, and experiments are performed to validate the antenna design. The proposed antenna sized 42.4 mm x 42.4 mm x 0.2032 mm (0.57 lambda(o) x 0.57 lambda(o) x 0.0027 lambda(o) at 4.05 GHz) has an |S11| < -10 dB impedance bandwidth of 2.92-5.15 GHz (55.26%) and a 3 dB AR bandwidth of 2.96-5.12 GHz (53.5%)
Electron Beam Loss Monitor of Areal Accelerator Based on Pin-Photodiodes
No full textA prototype PIN-photodiode-based electron system for flux measurement of the AREAL accelerator electron beam (energy up to 5 MeV) was developed and tested. The system can be eventually used to measure beam losses from the vacuum chamber of the SASE100 undulator, which is intended for the generation of radiation in the terahertz range and will be installed in the AREAL accelerator tract during its modernization. The method of using the PIN-photodiodes as a beam loss monitor is based on the effect of electron-hole pairs formation when ionizing particles pass through the photodiode barrier layer. Calculations of the interaction of electrons with the substance of the barrier layer are performed using the PCLab program. The experiments carried out on the accelerator electron beam showed that the developed system can effectively register the electron fluxes of both the main beam of the AREAL accelerator and its dark current
Tuning the Coordination Environment of Carbon-Based Single-Atom Catalysts via Doping with Multiple Heteroatoms and Their Applications in Electrocatalysis
No full textCarbon-based single-atom catalysts (SACs) are considered to be a perfect platform for studying the structure-activity relationship of different reactions due to the adjustability of their coordination environment. Multi-heteroatom doping has been demonstrated as an effective strategy for tuning the coordination environment of carbon-based SACs and enhancing catalytic performance in electrochemical reactions. Herein, recently developed strategies for multi-heteroatom doping, focusing on the regulation of single-atom active sites by heteroatoms in different coordination shells, are summarized. In addition, the correlation between the coordination environment and the catalytic activity of carbon-based SACs are investigated through representative experiments and theoretical calculations for various electrochemical reactions. Finally, concerning certain shortcomings of the current strategies of doping multi-heteroatoms, some suggestions are put forward to promote the development of carbon-based SACs in the field of electrocatalysis
Study on Biological Function of Saccharomyces Cerevisiae Bromodomain-containing AAA+ ATPase Yta7 Using Single-molecule Imaging
No full textBrand Exploration in Metaverse: Effects of Self-Avatar Resemblance on Brand Attitude and Purchase Intention, and Moderated Mediation of Copresence
No full textDevelopment of recombinant secondary antibody mimics (rSAMs) for immunoassays through genetic fusion of monomeric alkaline phosphatase with antibody binders
No full textIn conventional immunoassays, a secondary antibody is used to amplify the signal generated by the binding of the primary antibody to the target analyte. Due to concerns regarding animal use and cost-inefficiency of secondary antibody productions, there is a significant demand for the development of recombinant secondary antibody mimics (rSAMs). Here, we developed rSAMs using a signal-generating enzyme, monomeric alkaline phosphatase (mALP), and antibody-binders, including monomeric streptavidin (mSA2) and mouse IgG1- or rabbit IgG-binding nanobodies (MG1Nb or RNb). The mALP-MG1Nb, mALP-RNb, and mALP-mSA2 were genetically constructed and produced in large quantities using bacterial overexpression systems, which reduced manufacturing costs and time without the use of animals. Each rSAM exhibited high and selective binding to its respective primary antibody, generating linear band signals corresponding to the amounts of target analytes in western blots. The rSAMs also successfully generated sigmoidal signal curves that increased as the sample concentration increased. Moreover, they generated stronger signals than conventional ALP-conjugated secondary antibodies and SA, particularly in the medium to high sample concentration range, in both indirect and sandwich-type indirect ELISAs at the same sample concentration. The rSAMs we developed here may provide new insights to develop novel immunoassay-based analytical and diagnostic tools
Rechargeable Na-MnO2 battery with modified cell chemistry
No full textHigh voltage, high energy density, nominal cycle life, and low cost are the most critical requirements of rechargeable batteries for their widespread energy storage applications in electric vehicles and renewable energy technologies. Na-MnO2 battery could be a low-cost contender, but it suffers extensively from its low cell voltage and poor rechargeability. In this study, we modified the conventional cell structure of Na-MnO2 battery and established altered cell chemistry through a hybrid electrochemical process consisting of Na striping/plating at the anode and Zn2+ insertion/de-insertion along with MnO2 dissolution/deposition at the cathode. After the modification, Na-MnO2 battery exhibits a discharge capacity of 267.10 mA h/g and a cell voltage of 3.30 V (vs. Na/Na+), resulting in a high specific energy density of 881.43 Wh/kg. After 300 cycles, the battery retains 98% of its first-cycle discharge capacity with 100% coulombic efficiency. Besides, Na metal-free battery assembled using sodium biphenyl as a safer anode also delivers an excellent energy density of 810.0 Wh/kg. This work could provide a feasible method to develop an advanced Na-MnO2 battery for real-time energy storage applications.& COPY; 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved
Deep learning-based label-free hematology analysis framework using optical diffraction tomography
No full textHematology analysis, a common clinical test for screening various diseases, has conventionally required a chemical staining process that is time-consuming and labor-intensive. To reduce the costs of chemical staining, label-free imaging can be utilized in hematology analysis. In this work, we exploit optical diffraction tomography and the fully convolutional one-stage object detector or FCOS, a deep learning architecture for object detection, to develop a label-free hematology analysis framework. Detected cells are classified into four groups: red blood cell, abnormal red blood cell, platelet, and white blood cell. In the results, the trained object detection model showed superior detection performance for blood cells in refractive index tomograms (0.977 mAP) and also showed high accuracy in the four-class classification of blood cells (0.9708 weighted F1 score, 0.9712 total accuracy). For further verification, mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) were compared with values obtained from reference hematology equipment, with our results showing reasonable correlation in both MCV (0.905) and MCH (0.889). This study provides a successful demonstration of the proposed framework in detecting and classifying blood cells using optical diffraction tomography for label free hematology analysis
Potential of Carbon Nanotube Chemiresistor Array in Detecting Gas-Phase Mixtures of Toxic Chemical Compounds
No full textToxic industrial chemicals (TICs), when accidentally released into the workplace or environment, often form a gaseous mixture that complicates detection and mitigation measures. However, most of the existing gas sensors are unsuitable for detecting such mixtures. In this study, we demonstrated the detection and identification of gaseous mixtures of TICs using a chemiresistor array of single-walled carbon nanotubes (SWCNTs). The array consists of three SWCNT chemiresistors coated with different molecular/ionic species, achieving a limit of detection (LOD) of 2.2 ppb for ammonia (NH3), 820 ppb for sulfur dioxide (SO2), and 2.4 ppm for ethylene oxide (EtO). By fitting the concentration-dependent sensor responses to an adsorption isotherm, we extracted parameters that characterize each analyte-coating combination, including the proportionality and equilibrium constants for adsorption. Principal component analysis confirmed that the sensor array detected and identified mixtures of two TIC gases: NH3/SO2, NH3/EtO, and SO2/EtO. Exposing the sensor array to three TIC mixtures with various EtO/SO2 ratios at a fixed NH3 concentration showed an excellent correlation between the sensor response and the mixture composition. Additionally, we proposed concentration ranges within which the sensor array can effectively detect the gaseous mixtures. Being highly sensitive and capable of analyzing both individual and mixed TICs, our gas sensor array has great potential for monitoring the safety and environmental effects of industrial chemical processes
Development of Textured 0.37PMN-0.29PIN-0.34PT Ceramics-Based Multilayered Actuator for Cost-Effective Replacement of Single Crystal-Based Actuators
No full textMultilayered actuators using Pb(Mg1/3Nb2/3)O3-Pb(In1/2Nb1/2)O3-PbTiO3 (PMN-PIN-PT) crystals have demonstrated excellent properties, but are costly and lack mechanical strength. Textured PMN-PIN-PT ceramics exhibit robust mechanical strength and comparable properties to their single crystals form. However, the development of multilayered actuators using textured PMN-PIN-PT ceramics has not been achieved until now. This study presents the development of a multilayered actuator using textured 0.37PMN-0.29PIN-0.34PT ceramics with an Ag0.9/Pd0.1 inner electrode, co-fired at 950???. A random 0.37PMN-0.29PIN-0.34PT ceramics multilayered actuator was also developed for comparison. The multilayered actuator consisted of 9 ceramic layers (36 ??m thickness) with an overall actuator thickness of 0.401 mm. The textured and random 0.37PMN-0.29PIN-0.34PT ceramics-based multilayered actuators achieved displacements of 0.61 ??m (0.15% strain) and 0.23 ??m (0.057% strain) at a low applied peak voltage of 100 V. These results suggest that the developed multilayered actuator using high-performance textured 0.37PMN-0.29PIN-0.34PT ceramics has the potential to replace expensive single crystal-based actuators costeffectively