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Wetland ecosystems can be effectively managed to produce sustainable services and benefits for human beings. Thus, it is considered as an essential component of Earth's life-support system. It has been studied quantitatively, but few studies have focused on exact local characteristics of various wetlands in Greater Bay Area (GBA) to continuously quantify the value of ecological services. Against the background of fast urbanization and wetland degradation in GBA, as a famous ecological core in China, Huiyang is of great importance for its ecological, social, and cultural functions in the whole region. Thus, this study aims to provide decision-making references for wetland protection and development in this area. All the wetlands in Huiyang, including mangroves, inland tidal flats, and coastal tidal flats, were included as research objects. Based on the investigated wetland resources, multiple methods were combined to study their wetland services, including pollution prevention cost, substitution cost, and travel expense calculation. Creatively, five factors were selected by Analytic Hierarchy Process (AHP) method: water purification, carbon fixation, shore protection, biodiversity conservation, and leisure tourism. After a comparison, the results showed that the total value of wetland ecosystem services in Huiyang was nearly 30.47 million dollars in 2020. Among the three types of services, the value of leisure tourism service was dominant, accounting for 95%. Among the five factors, the ranking sequence was: leisure tourism, carbon sequestration, biodiversity conservation, shore protection, and water purification. Based on the results, this paper provides a basis for more cities to scientifically measure the value of their wetlands, further utilize the wetland services in a more balanced way. [ABSTRACT FROM AUTHOR]

The floatable photocatalysts were a new strategy towards real-world applications of photocatalytic degradation, which exhibited high utilization and recovery rate. Expand aple poly ephylene (EPE) was widely known as packaging fill materials, lots of used EPE as rubbish increased environment pollution. As it happens, EPE had the characteristics of light weight, abundant capillaries, which can be used as the carriers to prepare floatable photocatalysts. EPE/SnO2 was prepared through coprecipitation and low-temperature oxidation technique. In addition, the influence of Sn-doping amount, pH value, catalyst loading, the cationic and anionic on the photocatalytic efficiency toward rhodamine B (RhB) was investigated. Almost of the 50 mL RhB (15 mg/L) was decomposed within 50 min under visible-light. Importantly, the removal rate of the floatable photocatalysts EPE/SnO2 was fourteen times higher than pure SnO2 at 50 min. The removal efficiencies of EPE/SnO2 for RhB in tap water, river water and reservoir water were above 98% within 50 min. Moreover, the degradation efficiency of RhB still remained 96.3% after 10 recycling runs. Compared to the catalysts recently reported, the reusability of EPE/SnO2 was the highest. According to the free radical trapping experiment, 1O2, O2• − and h+ were confirmed the main reactive oxygen species participating the photocatalytic degradation over RhB. [ABSTRACT FROM AUTHOR]

CuO/CeO2 microsphere was viewed as an economical and environment-friendly heterogeneous photocatalyst, which was synthesized via a co-precipitation technique. The physicochemical properties of as-prepared samples were characterized by various methods. 20 mg/L of TC-HCl was degraded completely within 20 min at 1 mmol peroxymonosulfate (PMS) under UV-visible light. The scavenging experiments and electron paramagnetic resonance (EPR) technologies revealed that SO4· −, O2· − and ·OH were involved as active species in the CuO/CeO2/PMS system, which were responsible for efficient decomposition of TC-HCl. Moreover, it was applied to treat raw water containing TC-HCl, all the removal efficiencies were more than 89% within 22 min. The possible photocatalytic degradation mechanism for the TC-HCl was investigated. CuO/CeO2 exhibited significant light trapping enhancement after Ce introduced, which lead to enhance the photocatalytic performance. Therefore, the CuO/CeO2 can be utilized as an economical photocatalyst to activate PMS and decompose TC-HCl in aqueous solution. [ABSTRACT FROM AUTHOR]

Liquid helium (LHe) at 4.2 K was electronically excited using a corona discharge for both negative and positive high voltages. The experiments were carried out for different pressures in the range from 0.1 to 10 MPa at constant temperature. The light emitted from the zone close to the tip was spectroscopically analyzed showing features from atoms and excimer helium. The shifts and widths of the observed lines and bands were found to depend on the applied hydrostatic pressure and on the tip polarity. Our analysis showed that classic pressure broadening theory cannot account for the observed widths and shifts rather than the presence of bubbles which surround single excited atoms and molecules. For positive tip polarities red shifted features distinct from pure He and [He.sub.2]* were observed and tentatively assigned to 'red satellites'. Index Terms--Helium spectroscopy, corona discharge, excimer helium.

In view of photodegradation of antibiotics based on SnS2, larger specific surface area SnS2 microcubes remain rare. In this paper, shape-controlled SnS2 microcubes with defects were successfully prepared via a simple template-engaged strategy. The obtained microcubes manifested high specific surface area (43.80 m2 g−1). The degradation performance for Rhodamine B (RhB) was investigated in detail, including the effect of parameters, like different photocatalysts, pH, and catalyst dosage. The results indicated that degradation efficiency was 99.90% under visible light within 80 min. Moreover, the degradation efficiency was 79% after the four successive cycles. [ABSTRACT FROM AUTHOR]

Secondary soil salinization causes plant stress, which can be relieved by different ratios of red to far-red light (R:FR). Our study aimed to elucidate the role of low R:FR ratios treatments on photosynthesis and growth of tomato seedlings in salinized soils. Tomato seedlings were treated under three R:FR ratios and calcium nitrate was applied simultaneously. The results showed that the treatments under low R:FR ratios stimulated growth parameters of tomato seedlings under calcium nitrate stress, the best impact being achieved at the R:FR ratio of 0.7 in this experiment. Low R:FR ratios treatments increased proline content as well as PSII maximum efficiency, actual electron transport operating efficiency, and photochemical quenching of tomato seedlings under calcium nitrate stress but decreased the value of nonphotochemical quenching. Moreover, low R:FR ratios treatments promoted net photosynthetic rate and increased the expression of a Rubisco gene. In conclusion, low R:FR ratios treatments could improve the salt resistance of greenhouse tomato plants. [ABSTRACT FROM AUTHOR]

In this paper, the electrical tree growth characteristics of silicone rubber (SiR) are studied under impulse superimposed on DC voltage and a temperature gradient (TG) field. The temperature difference between high voltage (HV) and ground (GD) electrodes varies from -90 to 90 °C resulting in a TG field in the samples. The electrical tree morphology, length and accumulated damage are discussed. Experimental results show that with the increase of absolute value of TG, the electrical tree length and accumulated damage continue to increase, and the tree morphology turns from branch-like tree to bush-branch hybrid tree. The positive TG has a more obvious acceleration effect on the tree growth than does the negative TG. Under the TG, the temperature dependent carrier transport results in space charge accumulation and electric field distortion at low temperature side, which is the main reason for the different growth characteristics of electrical tree. Besides, the accumulated damage of DC superimposed with heteropolar impulse voltage is larger than that under DC superimposed with homopolar impulse voltage. It is concluded that the temperature gradient and impulse superimposed on DC voltage promote the electrical tree growth of HVDC cable accessories insulation. [ABSTRACT FROM AUTHOR]

In this paper, a high-field magnet experimental system is setup to investigate the dielectric properties of epoxy resin in the presence of high magnetic field. An asymmetric ferromagnetic electrode system is used to build gradient magnetic field and investigate its effect on tree characteristics of epoxy resin. Influence mechanisms of gradient magnetic field on dielectric properties and tree characteristics of epoxy resin are discussed through combining experimental results and simulation calculation. Experimental results show that electrical trees are more easily to be initiated and spread more rapidly in gradient magnetic field. The conductivity of the epoxy resin increases with the increase of magnetic field strength due to energy level splitting, which is analyzed through electrodynamics calculation. The relative permittivity decreases, and the dielectric loss tangents increase when high magnetic field is applied. Changes of conductivity and relative permittivity affect the charge behavior and electric field distribution in epoxy resin, resulting in the particular electrical tree. [ABSTRACT FROM AUTHOR]

In this work, nano-titanium oxide (TiO2) is encapsulated into boron nitride nanosheets (BNNS) by the calcination process to fabricate core-shell structured TiO2 @BNNS nanofillers. The effects of TiO2 @BNNS fillers on the DC conductivity, space charge and breakdown strength of polypropylene (PP) composites are investigated. Experimental results show that PP/TiO2 @BNNS composites have a lower temperature-dependent conductivity with an activation energy of 0.64 eV, which is much lower than that of PP, 0.95 eV. The DC breakdown strength of PP/TiO 2 @BNNS samples is 22.2% higher than that of PP at 90 °C. The average space charge density and electric field distortion rate of PP/TiO 2 @BNNS are reduced by 6.6 C/m3 and 23.3%, respectively, compared with PP, under a polarization electric field of 40 kV/mm at 90 °C. It is proven that TiO2 @BNNS nanofillers form numbers of electrical potential wells for charge carriers, thereby, inhibiting the hot electron transport and their damage to polymer molecules. This work provides an effective method to improve the dielectric performance of PP cable insulation. [ABSTRACT FROM AUTHOR]