The paper presents a new and simple printed microstriplinefed self-complementary antenna for the WLAN and WiMAX applications. This antenna is composed of an arrow-shaped self-complementary ...configuration (ASSC) and a simple 50Ω microstrip feedline. The proposed antenna has two
resonant structures, one of which is a half-arrow-shaped radiating monopole with a microstrip feedline, and the other is a complementary counterpart open slot on the extended ground plane. The ASSC mainly excites two resonant modes at 2.6 GHz and 3.8 GHz, respectively, in order to achieve
wideband operation. The measured results show that the impedance bandwidth for 10 dB return loss is 4.11 GHz (2.24-6.35 GHz), which corresponds with a fractional bandwidth of 95%, and it can simultaneously cover WLAN and WiMAX bands. The measured and simulated radiation patterns and
gains exhibit reasonable characteristics. In addition, the proposed antenna has a simple and compact size of 30 × 30 × 1.6 mm
3
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Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
By using polycrystalline Cr2+:ZnS ceramics with different transmissions as saturable absorbers (SAs), the different output performance of passively Q-switched (PQS) Ho:LuAG lasers end-pumped with ...continuous-wave (CW) Tm:YLF laser was demonstrated. When the transmission of the Cr2+:ZnS SA was 86.3%, the pulse duration changed from 50.6 to 46 ns as the absorbed pump power increased from 14.3 to 24 W. The pulse energy and repetition rate were tuned in the range of 2.4-2.9 mJ and 0.36-2.56 kHz, respectively. The output wavelength of the PQS laser shifted from 2100.6 nm (in CW operation) to 2098.3 nm. Using a Cr2+:ZnS SA with transmission of 93.9%, the Ho:LuAG laser achieved a maximum average output power of 5.4 W with slope efficiency of 44.2%.
Gas mixture of H2S and NH3 in this study has been the focus in the research area concerning gases generated from the animal husbandry and the anaerobic wastewater lagoons used for their treatment. A ...specific microflora (mixture of Thiobacillus thioparus CH11 for H2S and Nitrosomonas europaea for NH3) was immobilized with Ca-alginate and packed inside a glass column to decompose H2S and NH3. The biofilter packed with co-immobilized cells was continuously supplied with H2S and NH3 gas mixtures of various ratios, and the removal efficiency, removal kinetics, and pressure drop in the biofilter was monitored. The results showed that the efficiency remained above 95% regardless of the ratios of H2S and NH3 used. The NH3 concentration has little effect on H2S removal efficiency, however, both high NH3 and H2S concentrations significantly suppress the NH3 removal. Through product analysis, we found that controlling the inlet ratio of the H2S/NH3 could prevent the biofilter from acidification, and, therefore, enhance the operational stability. Conclusions from bioaerosol analysis and pressure drop in the biofilter suggest that the immobilized cell technique creates less environmental impact and improves pure culture operational stability. The criteria for the biofilter operation to meet the current H2S and NH3 emission standards were also established. To reach Taiwan's current ambient air standards of H2S and NH3 (0.1 and 1 ppm, respectively), the maximum inlet concentrations should not exceed 58 ppm for H2S and 164 ppm for NH3, and the residence time be kept at 72 s.
We present the first results from an all-sky all-frequency (ASAF) search for an anisotropic stochastic gravitational-wave background using the data from the first three observing runs of the Advanced ...LIGO and Advanced Virgo detectors. Upper limit maps on broadband anisotropies of a persistent stochastic background were published for all observing runs of the LIGO-Virgo detectors. However, a broadband analysis is likely to miss narrowband signals as the signal-to-noise ratio of a narrowband signal can be significantly reduced when combined with detector output from other frequencies. Data folding and the computationally efficient analysis pipeline, {\tt PyStoch}, enable us to perform the radiometer map-making at every frequency bin. We perform the search at 3072 {\tt{HEALPix}} equal area pixels uniformly tiling the sky and in every frequency bin of width $1/32$~Hz in the range $20-1726$~Hz, except for bins that are likely to contain instrumental artefacts and hence are notched. We do not find any statistically significant evidence for the existence of narrowband gravitational-wave signals in the analyzed frequency bins. Therefore, we place $95\%$ confidence upper limits on the gravitational-wave strain for each pixel-frequency pair, the limits are in the range $(0.030 - 9.6) \times10^{-24}$. In addition, we outline a method to identify candidate pixel-frequency pairs that could be followed up by a more sensitive (and potentially computationally expensive) search, e.g., a matched-filtering-based analysis, to look for fainter nearly monochromatic coherent signals. The ASAF analysis is inherently independent of models describing any spectral or spatial distribution of power. We demonstrate that the ASAF results can be appropriately combined over frequencies and sky directions to successfully recover the broadband directional and isotropic results.
Summary
Aims To evaluate the effect of metformin on glucose metabolism, insulin sensitivity and rate of conversion diabetes in people with impaired glucose tolerance (IGT).
Methods Seventy subjects ...with IGT were randomized under double‐blind conditions to receive either placebo (n = 37) or metformin (n = 33) at a dosage of 250 mg three times daily for a duration of 12 months. Glycaemic control, plasma insulin and other biochemical indexes were assessed before and after 3, 6 and 12 months.
Results At 12 months the conversion rate to diabetes was 16.2% in the placebo group compared to 3.0% for the metformin group (P = 0.011). Of subjects treated with metformin for 12 months, 84.9% became normoglycaemic compared to 51.4% of those receiving the placebo. Significant improvements in fasting glucose, glucose tolerance and insulin sensitivity were found at 12 months and at intermediate clinic assessments.
Conclusions Metformin can improve glucose metabolism in IGT patients and may be a treatment option in their management of IGT subjects.
Low density materials, such as hydrogen silsesquioxane (HSQ), can offer lower dielectric constants. With HSQ, a low value of K can be achieved if the density of Si-H bonding is maintained at a high ...level and the formation of -OH bonds and absorption or creation of water in the film is minimized. In this work, we have studied the use of hydrogen plasma to improve the quality of HSQ. In addition, the effects of N sub(2) and O sub(2) plasma post-treatments on HSQ are investigated. The leakage current of HSQ decreases as the H sub(2) plasma treatment time is increased. However, the leakage current of HSQ increases as the N sub(2) and O sub(2) plasma treatment time is increased. A model is proposed to explain the role of hydrogen in HSQ. The hydrogen passivates the surface of porous HSQ. The H sub(2) plasma treatment provides additional hydrogen passivation of the HSQ. On the other hand, the N sub(2) and O sub(2) plasma treatments reduce the hydrogen passivation of HSQ. As a result, both the leakage current and dielectric constant increase as the N sub(2) and O sub(2) plasma treatment time is increased. Finally, HSQ with H sub(2) plasma treatment is used as the intermetal dielectric in a multilevel interconnection structure. Consistent with our model, the via resistance decreases with increasing H sub(2) plasma treatment time.
For the first time, we present a state-of-the-art energy-efficient 16nm technology integrated with FinFET transistors, 0.07um 2 high density (HD) SRAM, Cu/low-k interconnect and high density MiM for ...mobile SoC and computing applications. This technology provides 2X logic density and >35% speed gain or >55% power reduction over our 28nm HK/MG planar technology. To our knowledge, this is the smallest fully functional 128Mb HD FinFET SRAM (with single fin) test-chip demonstrated with low Vccmin for 16nm node. Low leakage (SVt) FinFET transistors achieve excellent short channel control with DIBL of <;30 mV/V and superior Idsat of 520/525 uA/um at 0.75V and Ioff of 30 pA/um for NMOS and PMOS, respectively.
It has long been problematic to remove the oxide barrier layer between the template nanopores and the aluminum base in the electrochemical deposition of metallic nanorods into the anodic aluminum ...oxide template. A novel method has been developed to solve this problem by simply reducing the voltage in a stepwise method in the anodation process. Using the developed method, we have been able to obtain ordered nickel nanorod arrays with regular rods of controllable sizes. Mechanism of the growth was discussed.
We have systematically studied the effect of the solvent nature on the self-assembly of H-shaped block copolymers with a poly(ethylene glycol) backbone and polystyrene branches, i.e., (PS)2PEG(PS)2. ...Two copolymers with different molecular weights (MW) and compositions, copolymer 1 and copolymer 2, were used, where copolymer 2 has a higher MW and higher PEG fraction than those of copolymer 1. In nominally neutral (nonselective) solvents, it is found that very subtle variation in the solvent affinity can remarkably influence the morphologies of the films spin-coated from the corresponding solutions. For example, as the solvent was changed from PS-affinitive to PEG-affinitive, the films of copolymer 1 changed from a disordered state into PEG cylinders. In contrast, the films of copolymer 2 changed from wormlike patterns into PEG spheres. Besides, the surface morphologies also showed some dependence on the solution concentration: with decreasing concentration, the PEG cylinders were changed into PEG spheres and a disordered state. In PEG-selective solvent (e.g., acetonitrile), copolymer 2 formed typical spherical micelles. In contrast, copolymer 1 formed a mixture of spheres and cylinders, which could be transformed into vesicles and lamellae upon dilution. The polymer−solvent interactions and their effects on the copolymer chain conformation are discussed.
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