Abstract The objective of this study was to investigate the effects of combined low-pressure ultraviolet (UV)irradiation and chlorination on the formation of disinfection by-products (DBPs) from different dissolved organic matter (DOM) as DBP precursors. Commercially available humic acid (HA), extracellular organic matter (EOM) from green algae, cyanobacteria, and diatom, namely Scenedesmus quadricauda (SQ), Merismopedia sp. (Msp), and Phaedactylum tricornutum (PT), were used as the sources of DOM. The DBP formation increased with increasing total residual chlorine; EOM from PT presented the highest formation potential followed by HA, Msp, and SQ. The low dosage of 40 mJ/cm2 UV irradiation is insignificant to change the DBP formation from HA and SQ; however, it decreased the DBP formation from bromide-containing EOM of PT and promoted the DBP formation from EOM of Msp at various total residual chlorines. The DBP formation of each DOM correlated well with total residual chlorine. The maximum DBP formation potential (DBPFP) reduction of 42.25 and 13.75% for haloacetic acid formation potential (HAAFP) and trihalomethane formation potential (THMFP) was obtained at the UV irradiation dosage of 300 mJ/cm2 for EOM of PT. However, for the EOM derived from Msp, a maximum increase of 58.1 and 51.1% for HAAFP and THMFP was observed after UV-chlorination.
Abstract In this article, a systematic theory and design approach are presented to achieve bandwidth expansion of the Doherty power amplifier (DPA) by using extended continuous Class‐GF (ECCGF) power amplifiers (PAs) as carrier PAs. The results of the theoretical analysis indicate that compared to conventional DPA, introducing ECCGF PA as carrier PA into the DPA design can establish two larger target impedance spaces with overlapping regions for saturation and output back‐off (OBO) power levels, which can reduce the design complexity of impedance inverter networks (IINs) while achieving DPA bandwidth expansion. Based on this, the proposed design theory is validated in the design and fabrication of a prototype DPA employing the CGH40010F GaN HEMT provided by MACOM. The measured results show that under continuous wave excitation, the designed DPA delivers a saturated output power of 43.1–44.2 dBm in the range of 1.3–2.7 GHz with a relative bandwidth of 70%. The drain efficiencies of 61.2%–73.2% and 42.5%–52.7% are achieved over the entire band at the saturation and 6‐dB OBO power levels, respectively. The measured results also confirmed the theoretical findings.
The insulation structure of oil-immersed paper (OIP) capacitive bushing is usually designed without considering the effect of temperature gradient on material properties during the bushing operating. In this paper, partial discharge inception voltage (PDIV) test, and permittivity test were carried out on the OIP at various temperatures. An electricity-fluid-temperature multi-physics field simulation model was built and analyzed by the finite element analysis (FEA) based on the experimental data. The results show that the electric properties of OIP are changed obviously under the operating conditions. The voltage of each layer is basically unchanged, but the PDIV decreased by 14.8%. In addition, an optimization design of OIP capacitive bushing based on the temperature gradient was proposed, which realized the uniform axial electric field distribution of the bushing during its operation. This study offers a new perspective on the design of OIP capacitive bushing.
Abstract The interactions of six typical antibiotics, including azithromycin, clarithromycin (CLR), ciprofloxacin, sulfathiazole, sulfamethoxazole, and tetracycline (TCY), with Microcystis aeruginosa were investigated, discussing the effects of antibiotics on algal growth in terms of mono‐ and co‐antibiotics, and the removal of six antibiotics by the alga. The results showed that all the antibiotics showed “low‐promoting and high‐inhibiting” effects, except for sulfonamides, which showed a promotion trend on algal cell density and chlorophyll a . The tests of half effective concentrations (EC 50 s) of antibiotics against M. aeruginosa showed that the antibiotics of the same category had similar EC 50 s, and the toxicity effects of co‐antibiotics were higher compared to mono‐antibiotics. The toxic effects of antibiotics against M. aeruginosa were antagonistic in most binary co‐antibiotics, and synergistic and simple additive effects in the ternary co‐antibiotics. For removal tests of antibiotics by the alga, it could be seen that at the same concentration (10 µg L −1 ), M. aeruginosa showed the best removal of TCY with 22.8% and the lowest removal of CLR with only 5.8%. It was found that both antibiotics and M. aeruginosa had mutual influences; therefore, the interaction might be favorable to the permanent removal of antibiotics and reduce the impact on the aquatic ecological environment.
In order to know the effects of micropore oxygen aeration on the water quality and economic output, take each 3 of micropore oxygen aeration (experimental pond) and impeller oxygenation (control pond) to make the comparison, indexs of two different aeration methods water were detected from May, 2012 to October, 2012. Such as water temperature, dissolved oxygen, ammonia nitrogen and nitrite, phytoplankton, chemical oxygen demand (CODMn). Results showed that, (1) the indexes of the dissolved oxygen, ammonia nitrogen, chemical oxygen demand (CODMn) and nitrite of the experimental pond are all superior to that of the control pond, of which the concentration of the dissolved oxygen of the experimental pond is 8.37 mg/L which is higher than that of the control pond (5.7 mg/L). And, CODMn in the experimental pond is 7.54 mg/L, lower than that in the control pond (10.19 mg/L). The difference between the control pond and the experimental pond was statistically significant (p<0.01). The ammonia nitrogen of the experimental pond is 0.1 mg/L, obviously lower than the control pond (0.16 mg/L). Besides, the nitrite is 0.13 mg/L in the experimental pond, lower than that of the control pond (0.21 mg/L). (2) Compared with the control pond, the experimental pond has quite higher general abundance of algae, with about 5.69×108 ind/L. Yet, there is no obvious difference between them. (3) Compared to the impeller oxygenation, the micropore oxygen aeration technology can be better to increase the dissolved oxygen in the aquaculture pond and improve the water quality. However, there is no significant influence to the phytoplankton abundance and diversity.
This paper presents a Doherty power amplifier chip integrated Slot Antenna. To facilitate gold wire bonding, the thickness of the antenna substrate is only 0.127mm. The antenna adopts power division structure. By using double feed points, the slot can superimpose and excite additional resonant modes to expand the bandwidth of the antenna. After gold wire bonding with the previous DPA. The impedance bandwidth of proposed antenna is about 41.92%, and the gain in the maximum radiation direction is about 5.1dBi. The overall link has low loss and good radiation performance, which provides a feasible direction for the integration of antenna and power amplifier.
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