Current Issue : October - December Volume : 2018 Issue Number : 4 Articles : 5 Articles
Waveguides formed by etching, proton-exchange (PE), and strip-loaded on single-crystal\nlithium niobate (LN) thin film were designed and simulated by a full-vectorial finite difference method.\nThe single-mode condition, optical power distribution, and bending loss of these kinds of waveguides\nwere studied and compared systematically. For the PE waveguide, the optical power distributed in\nLN layer had negligible change with the increase of PE thickness. For the strip-loaded waveguide,\nthe relationships between optical power distribution in LN layer and waveguide thickness were\ndifferent for quasi-TE (q-TE) and quasi-TM (q-TM) modes. The bending loss would decrease with\nthe increase of bending radius. There was a bending loss caused by the electromagnetic field leakage\nwhen the neff of q-TM waveguide was smaller than that of nearby TE planar waveguide. LN ridge\nwaveguides possessed a low bending loss even at a relatively small bending radius. This study is\nhelpful for the understanding of waveguide structures as well as for the optimization and the fabrication\nof high-density integrated optical components....
This study compares wind speeds derived from five satellite microwave radiometers with\nthose directly observed by buoy-mounted anemometers and the global analyses produced by the\nEuropean Center for Medium-RangeWeather Forecasts (ECMWF) model. Buoy comparisons yield\nwind speed root mean square errors of 0.82 m/s forWindSat, 1.45 m/s for SSMIS F16, 1.39 m/s for\nSSMIS F17, 1.43 m/s for AMSR-E, and 1.45 m/s for AMSR2. The overall mean bias for each satellite is\ntypically <0.25 m/s when averaged over all selected buoys for a given study time. The satellite wind\nspeeds are underestimated with respect to the buoy observations at a band of the tropical Pacific\nOcean from âË?â??8ââ??¦S to 4ââ??¦N. The mean buoyââ?¬â??satellite difference as a function of year is always <0.4 m/s,\nexcept for SSMIS F16. The selected satellite wind speeds show an obvious seasonal characteristic at\nhigh latitudes. In comparison with the ECMWF data, some obviously positive differences exist at\nhigh southern latitudes in January and at high northern latitudes in July....
The interfacial adhesion of recycled carbon fiber (CF) reinforced epoxy composite heated\nby microwave (MW) irradiation were investigated by changing the curing state of the epoxy resin.\nThe recycled CF was recovered from the composite, which was prepared by vacuum-assisted resin\ntransfer molding, by thermal degradation at 500 or 600 ââ??¦C. Thermogravimetric analysis showed\nthat the heating at 600 ââ??¦C caused rough damage to the CF surface, whereas recycled CF recovered\nat 500 ââ??¦C have few defects. The interfacial shear strength (IFSS) between recycled CF and epoxy\nresin was measured by a single-fiber fragmentation test. The test specimen was heated by MW after\nmixing the epoxy resin with a curing agent or pre-curing, in order to investigate the curing effects\non the matrix resin. The IFSSs of the MW-irradiated samples were significantly varied by the curing\nstate of the epoxy resin and the surface condition of recycled CF, resulting that they were 99.5 to\n131.7% of oven heated samples Furthermore, rheological measurements showed that the viscosity\nand shrinking behaviors of epoxy resin were affected based on the curing state of epoxy resin before\nMW irradiation....
Breast cancer is the leading cause of death among females, early diagnostic methods with\nsuitable treatments improve the 5-year survival rates significantly. Microwave breast imaging has\nbeen reported as the most potential to become the alternative or additional tool to the current gold\nstandard X-ray mammography for detecting breast cancer. The microwave breast image quality is\naffected by the microwave sensor, sensor array, the number of sensors in the array and the size of the\nsensor. In fact, microwave sensor array and sensor play an important role in the microwave breast\nimaging system. Numerous microwave biosensors have been developed for biomedical applications,\nwith particular focus on breast tumor detection. Compared to the conventional medical imaging and\nbiosensor techniques, these microwave sensors not only enable better cancer detection and improve\nthe image resolution, but also provide attractive features such as label-free detection. This paper\naims to provide an overview of recent important achievements in microwave sensors for biomedical\nimaging applications, with particular focus on breast cancer detection. The electric properties of\nbiological tissues at microwave spectrum, microwave imaging approaches, microwave biosensors,\ncurrent challenges and future works are also discussed in the manuscript....
Recent developments in photonics-based microwave image-reject mixers (IRMs) are reviewed\nwith an emphasis on the pre-filtering method, which applies an optical or electrical filter to remove the\nundesired image, and the phase cancellation method, which is realized by introducing an additional\nphase to the converted image and cancelling it through coherent combination without phase shift.\nApplications of photonics-based microwave IRM in electronic warfare, radar systems and satellite\npayloads are described. The inherent challenges of implementing photonics-based microwave IRM to\nmeet specific requirements of the radio frequency (RF) system are discussed. Developmental trends of\nthe photonics-based microwave IRM are also discussed....
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