This paper presents a novel micromachining process to fabricate a 140 GHz planar antenna based on gap waveguide technology to be used in the next-generation backhauling links. The 140 GHz planar array antenna consists of three layers, all of which have been fabricated using polymer-based microfabrication and injection molding. The 140 GHz antenna has the potential to be used as an element in a bigger 3D array in a line-of-sight (LOS) multiple input multiple output (MIMO) configuration to boost the network capacity. In this work, we focus on the fabrication of a single antenna array element based on gap waveguide technology. Depending on the complexity of each antenna layer’s design, three different micromachining techniques, SU8 fabrication, polydimethylsiloxane (PDMS) molding, and injection molding of the polymer (OSTEMER), together with gold (Au) coating, have been utilized to fabricate a single 140 GHz planar array antenna. The input reflection coefficient was measured to be below???11 dB over a 14% bandwidth from 132 to 152 GHz, and the antenna gain was measured to be 31 dBi at 140 GHz, both of which are in good agreement with the simulations.
Water Resources Management - Continuous and accurate drought monitoring has an important role in early warning drought mitigation policies. This study aims to provide an accurate standardized... 相似文献
An automated FTIR method for the determination of the base content (BC(pKa)) of oils at rates of > 120 samples/h has been developed. The method uses a 5% solution of trifluoroacetic acid in 1-propanol (TFA/P) added to heptane-diluted oil to react with the base present and measures the ν(COO(-)) absorption of the TFA anion produced, with calibrations devised by gravimetrically adding 1-methylimidazole to a heptane-TFA/P mixture. To minimize spectral interferences, all spectra are transformed to 2(nd) derivative spectra using a gap-segment algorithm. Any solvent displacement effects resulting from sample miscibility are spectrally accounted for by measurement of the changes in the 1-propanol overtone band at 1936 cm(-1). A variety of oils were analyzed for BC(0.5), expressed as mEq base/g oil as well as converted to base number (BN) units (mg KOH/g oil) to facilitate direct comparison with ASTM D2896 and ASTM D974 results for the same samples. Linear relationships were obtained between FTIR and D2896 and D974, with the ASTM methods producing higher BN values by factors of ~1.5 and ~1.3, respectively. Thus, the FTIR BC method correlates well with ASTM potentiometric procedures and, with its much higher throughput, promises to be a useful alternative means of rapidly determining reserve alkalinity in commercial oil condition monitoring laboratories. 相似文献
The current research project has been devoted to isolating new low cost and eco-friendly phenolic compounds from fruit seeds, peels and vegetables to reduce the atmospheric pollution. Natural phenolic compounds were extracted from different fruit seeds and agriculture waste: P. armeniaca, P. persica, P. domestica and Triticum aesativum. The total phenolic content was quantified, and the maximum value (1 mL extract having 1,933 μg) was found in P. armeniaca seed extract. Phytochemical screening showed that P. armeniaca seeds contain higher amount of alkaloid, tannins, saponins and flavonoid. P. armeniaca seeds enhanced the biotransformation of reactive yellow dye up to 69.89% with maximum laccase (322.45 IU/mL) production. Biodegradation of reactive yellow was only 23.34% without natural redox mediator at sixth day of incubation. Use of P. armeniaca seed stimulators resulted in maximum laccase activity (894.4 IU/mL) with 99.5% rate of removal. UV-Vis, HPLC & FTIR analysis confirmed the transformation of parent dye into various new products. Phytotoxicity study indicated 0% germination index of Avena sativa seeds with reactive yellow, whereas 83% germination index having 100% seed germination while 83% root elongation with treated sample. Thus, the study revealed that the natural phenolic compounds could serve as high potential redox mediators for enhanced laccase-mediated decolorization of reactive yellow dye. 相似文献
Ischemic heart disease can lead to myocardial infarction (MI), a major cause of morbidity and mortality worldwide. Multiple stem cell types have been safely transferred into failing human hearts, but the overall clinical cardiovascular benefits have been modest. Therefore, there is a dire need to understand the basic biology of stem cells to enhance therapeutic effects. Bmi1 is part of the polycomb repressive complex 1 (PRC1) that is involved in different processes including proliferation, survival and differentiation of stem cells. We isolated cortical bones stem cells (CBSCs) from bone stroma, and they express significantly high levels of Bmi1 compared to mesenchymal stem cells (MSCs) and cardiac-derived stem cells (CDCs). Using lentiviral transduction, Bmi1 was knocked down in the CBSCs to determine the effect of loss of Bmi1 on proliferation and survival potential with or without Bmi1 in CBSCs. Our data show that with the loss of Bmi1, there is a decrease in CBSC ability to proliferate and survive during stress. This loss of functionality is attributed to changes in histone modification, specifically histone 3 lysine 27 (H3K27). Without the proper epigenetic regulation, due to the loss of the polycomb protein in CBSCs, there is a significant decrease in cell cycle proteins, including Cyclin B, E2F, and WEE as well as an increase in DNA damage genes, including ataxia-telangiectasia mutated (ATM) and ATM and Rad3-related (ATR). In conclusion, in the absence of Bmi1, CBSCs lose their proliferative potential, have increased DNA damage and apoptosis, and more cell cycle arrest due to changes in epigenetic modifications. Consequently, Bmi1 plays a critical role in stem cell proliferation and survival through cell cycle regulation, specifically in the CBSCs. This regulation is associated with the histone modification and regulation of Bmi1, therefore indicating a novel mechanism of Bmi1 and the epigenetic regulation of stem cells. 相似文献