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In order to fully understand the inorganic water-soluble ions and their sources in the atmospheric fine particles PM2.5 in Beijing after coal-to-gas conversion, 41 PM2.5 samples were continuously collected in Haidian District of Beijing during the winter heating period in 2017.The concentrations of 10 kinds of water-soluble ions(Na+, NH4+, K+, Ca2+, Mg2+, F-, Cl-, NO2-, NO3-, SO42-)were analyzed by ion chromatography.The results show that the daily average mass concentration of PM2.5 in Beijing during the sampling period is (94.28±52.49) μg/m3.Compared with the winter of 2016, the average daily PM2.5 concentration in Beijing in 2017 decreased by 29 μg/m3, with a decrease of 28.2%, and the number of pollution days decreased significantly.During the pollution period, NO3-, SO42-, and NH4+in the particulate matter were significantly higher than the clean period.The ratio of the concentration of ρ(NO3-)/ρ(SO42-) is greater than 1, and the contribution of the mobile source is relatively large, reflecting that the implementation of the "coal to gas" policy has contributed to the reduction of sulfate emissions from fixed sources such as coal.Time-of-flight secondary ion mass spectrometry(TOF-SIMS) was combined with mass high resolution mode and positive and negative ion imaging mode to characterize PM2.5.The results show that NH4+tends to exist in the form of molecular ammonium sulfate or ammonium hydrogen sulfate during the pollution period.

The disasters of encounter of extreme rainstorm and high tide level will aggravate the flood in coastal cities.In order to explore the impact of the encounter of rainstorm and tide on flood control and drainage in coastal cities,based on the annual maximum 1 day rainfall and its corresponding tide level data of Chiwan Station in Shenzhen from 1967 to 2018,the Copula function is used to construct a joint distribution model of annual maximum 1 day rainfall and its corresponding tide level,and the co-occurrence risk,the flood control risk,the condition risk and the combination risk of rain and tide in Shenzhen are calculated and analyzed.The results show that the risk of the encounter of rain and tide in Shenzhen is small,and the co-occurrence and combination risk probability of rainfall whose return period greater than 100 years and tidal level whose return period greater than 200 years are only 0.12% and 0.09%.The probability of the occurrence of rainfall or tide exceeding the standard magnitude is 1.09%,and its return period is less than 100 years.When the rainfall exceeds the standard magnitude,the probability of encountering an over-standard tide level is greater,with a probability of 12.33%.At the same time,with the increase of rainfall,the risk will also increase.Therefore,in the planning and design of flood and tide prevention and drainage in cities,the focus should be on attention and prevention.

In this paper, a hybrid particle swarm optimization (HPSO) algorithm is proposed to solve the problem of optimal water operation of cascade reservoirs in dry season. Based on the basic particle swarm optimization (PSO) algorithm, chaos algorithm is introduced to traverse the search space to generate the initial population and improve the global searching ability of the algorithm. A self-adaptive inertial weighting method based on optimized inertial weighting coefficient is adopted to improve the ability of particle individual search and avoid local optimum. The proposed algorithm is applied to the optimal water operation in dry season of cascade reservoirs on the mainstream of Xijiang River. The results show that the HPSO algorithm can effectively improve the guarantee degree of ecological flow and suppressing salinity flow in the control reach of Wuzhou station under different typical dry year scenarios.

The river basin cascade development has prominent influence on water ecology for breeding of four major Chinese carps, and the determination of ecological operation objectives is an important basic work to carry out the ecological operation. This study determines the main control indexes of reservoir operation by analysing the relationships between larval population of Xijiang Dongta spawning ground and impact indexes like water temperature, flood process and flow velocity. Taking peak flow, initial discharge, flow rising range, daily increasing rate of flow and duration of water level rising of the spawning ground as the control indexes, the target flow process of reservoir ecological operation can be determined. Furthermore, the drifting velocity of fish eggs is used as the test index to control the section flow in the scheduling river reach. The proposed method is applied to the ecological operation of Dongta spawning ground, and the target flow processes of ecological operation under low, medium and high flow levels are obtained.

Interspecific and intraspecific interactions are integral components of antagonistic and mutualistic networks of all animal species. These interactions are affected by various factors, such as morphological, physiological, and genetic characteristics. However, the impact of personality traits on animal inter- and intraspecific interactions remains unclear. We investigated the role of different personality types (proactive and reactive) in Lasiopodomys brandtii. We examined both intraspecific interactions with Lasiopodomys brandtii and interspecific interactions with Kunming mice. We found that for intraspecific interactions, proactive individuals had higher numbers of contacts with opponents, spent more time in the vicinity of an opponent, and moved greater distances within the vicinity of an opponent. For interspecific interactions, proactive individuals had higher numbers of contacts with opponents than reactive individuals. These results suggest that proactive individuals, especially male voles, tend to occupy dominant positions in both intraspecific and interspecific relationships. Consequently, our study is meaningful in understanding how personality traits affect animal behavior, species niche differentiation, and community dynamics and local biodiversity. [ABSTRACT FROM AUTHOR]

Multivariate rare-earth co-doped zirconia is one of the candidate materials for ultra-high-temperature thermal barrier coatings. GdYb-8YSZ (90ZrO2-4Y2O3-3Gd2O3-3Yb2O3, mol.%) nanopowder and its bulk ceramic were successfully fabricated. Microstructure, thermal conductivity and sintering behavior of GdYb-8YSZ ceramic at 1400 °C were investigated. The results showed that GdYb-8YSZ nanopowder was composed of a single c-ZrO2 phase with the particle size in the range of 20-40 nm. The thermal conductivity of GdYb-8YSZ does not change much with temperature, in the range of 1.31-1.74 W m−1 K−1 from room temperature to 1400 °C. This is mainly due to the coupling effect of oxygen vacancy defects, lattice distortion and photon heat conduction. However, the grain size of GdYb-8YSZ ceramic gradually increased from 1.43 in the as-prepared state to 3.44 μm after 96 h sintering, and GdYb-8YSZ had good high-temperature phase stability and poor sintering resistance at 1400 °C. [ABSTRACT FROM AUTHOR]

Coastal macroalgae may be subjected to global and local environmental stressors, such as ocean acidification and heavy-metal pollution. We investigated the growth, photosynthetic characteristics, and biochemical compositions of juvenile sporophytes of Saccharina japonica cultivated at two pCO2 levels (400 and 1000 ppmv) and four copper concentrations (natural seawater, control; 0.2 μM, low level; 0.5 μM, medium level; and 1 μM, high level) to better understand how macroalgae respond to ongoing environmental changes. The results showed that the responses of juvenile S. japonica to copper concentrations depended on the pCO2 level. Under the 400 ppmv condition, medium and high copper concentrations significantly decreased the relative growth rate (RGR) and non-photochemical quenching (NPQ) but increased the relative electron transfer rate (rETR) and chlorophyll a (Chl a), chlorophyll c (Chl c), carotenoid (Car), and soluble carbohydrate contents. At 1000 ppmv, however, none of the parameters had significant differences between the different copper concentrations. Our data suggest that excess copper may inhibit the growth of juvenile sporophytes of S. japonica, but this negative effect could be alleviated by CO2-induced ocean acidification. [ABSTRACT FROM AUTHOR]

The combined effect of elevated pCO2 (Partial Pressure of Carbon Dioxide) and decreased salinity, which is mainly caused by freshwater input, on the growth and physiological traits of algae has been poorly assessed. In order to investigate their individual and interactive effects on the development of commercially farmed algae, the juvenile sporophytes of Saccharina japonica were cultivated under different levels of salinity (30, 25 and 20 psu) and pCO2 (400 and 1000 µatm). Individually, decreased salinity significantly reduced the growth rate and pigments of S. japonica, indicating that the alga was low-salinity stressed. The maximum quantum yield, Fv/Fm, declined at low salinities independent of pCO2, suggesting that the hyposalinity showed the main effect. Unexpectedly, the higher pCO2 enhanced the maximum relative electron transport rate (rETRmax) but decreased the growth rate, pigments and soluble carbohydrates contents. This implies a decoupling between the photosynthesis and growth of this alga, which may be linked to an energetic reallocation among the different metabolic processes. Interactively and previously untested, the decreased salinity offset the improvement of rETRmax and aggravated the declines of growth rate and pigment content caused by the elevated pCO2. These behaviors could be associated with the additionally decreased pH that was induced by the low salinity. Our data, therefore, unveils that the decreased salinity may increase the risks of future CO2-induced ocean acidification on the production of S. japonica. [ABSTRACT FROM AUTHOR]

In this study, the blend of polycarbonate (PC)/poly(L-lactide) (PLLA) (70/30) was prepared through the conventional extrusion-injection-molding process. The morphology of the blend was characterized using scanning electron microscope. Both differential scanning calorimetry and wide angle X-ray diffraction were used to investigate the crystallization behavior of PLLA component in the blend. The mechanical and thermal properties of the blend were comparatively investigated, and the hydrolytic degradation ability of the material was also evaluated. The results show that the dispersed-PLLA particles are in the amorphous state in the PC matrix. Although the blend is immiscible, the rigid PLLA particles exhibit the toughening and reinforcement effects on PC simultaneously. Specifically, the heat-distortion temperature of the blend is comparable to that of pure PC. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

In this work, a novel nucleating agent (NA) based on substituted-aryl phosphate salts was introduced into poly(L-Lactide) (PLLA). The nonisothermal and isothermal crystallization behaviors of nucleated PLLA samples were investigated through differential scanning calorimetry (DSC), wide angle X-ray diffraction, and polarized optical microscope (POM). Furthermore, the effect of annealing treatment on the cold crystallization behaviors of nucleated samples was also investigated. The results show that the crystallization of PLLA, whether for the melt crystallization (including nonisothermal and isothermal crystallization process) or for the cold crystallization (including the cold crystallization occurring during the DSC heating process and during the annealing process), is greatly dependent upon the content of NA. At relatively lower NA content (≤0.1 wt%), the nucleation effect of NA is inconspicuous, however, at higher NA content (≥0.2 wt%), it exhibits great nucleation effect for the crystallization of PLLA. Further results show that the double endothermic peak of PLLA depends on the temperature applied for the crystallization. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Toughening of poly( L-lactide) (PLLA) by elastomer attracts much attention in recent years; however, it is usually associated with the deterioration of modulus and/or strength, resulting in limitation in many applications of the material. In this work, functionalized multiwalled carbon nanotubes (FMWCNTs) were introduced into ethylene- co-vinyl acetate toughened PLLA blends. The effects of FMWCNTs content on crystalline structure of PLLA matrix and the morphology of the blends, as well as the selective distribution of FMWCNTs in the ternary nanocomposites were investigated using differential scanning calorimetry (DSC), wide angle X-ray diffraction, scanning electron microscope, and transmission electron microscope. The results show that FMWCNTs exhibit excellent nucleation role in improving the cold crystallization behaviors of PLLA during the annealing and/or DSC heating processes. The results of mechanical property measurements demonstrate that the modulus, strength, and ductility of the blends can be further improved simultaneously through introducing FMWCNTs. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Poly( L-lactide)/multiwalled carbon nanotubes (PLLA/MWCNTs) nanocomposite recently attracts much attention because of its excellent comprehensive properties including improved thermostability, tensile strength, and conductivity. However, the nanocomposite exhibits similar brittleness compared with unmodified PLLA. In this work, a polar elastomer, that is, ethylene- co-vinyl acetate (EVA), was introduced into PLLA/MWCNTs nanocomposite. The selective distribution of MWCNTs and the effects of EVA on crystalline structure of PLLA were investigated using scanning electron microscope, transmission electron microscope, differential scanning calorimetry, and wide angle X-ray diffraction. The results show that the presence of EVA induces the change of the distribution of MWCNTs in the nanocomposites, and consequently, the cold crystallization of PLLA is prevented. With the increase of EVA content, both the ductility and the impact resistance of PLLA/FMWCNTs are improved greatly, indicating the toughening effect of EVA on PLLA/MWCNTs nanocomposite. The decreased tensile strength and modulus can be compensated through annealing treatment. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 [ABSTRACT FROM AUTHOR]

Hydrogels prepared from natural polysaccharide, such as chitosan, have attracted much attention owing to their advantageous physicochemical properties and functions. Therefore, it is of great significance to develop novel crosslinking and preparation methods for hydrogels. Here, a class of multifunctional chitosan-based (CBT) hydrogels were prepared from 3-carboxy-5-nitrophenylboronic acid (PBA) modified carboxymethyl chitosan (CMCS) and tannic acid (TA) by double crosslinking of borate ester and hydrogen bonds. They could rapidly gel within 1 min through physical blending under physiological conditions. They had good physicochemical properties such as injectability, plasticity, self-healing, swelling and biodegradability. They also exhibited the inherent viscoelastic behavior of hydrogels and had a maximum compressive strength of up to 0.31 Mpa. Moreover, they had excellent biocompatibility, hemostatic ability and antioxidant ability. Their maximum antibacterial rate against S. aureus and E.coli were up to 85.22 ± 2.73 % and 48.50 ± 1.04 %, respectively. They could be loaded with the model drug curcumin through borate ester bond and achieve glucose-sensitive controlled release. Preliminary in vivo experiments also showed good biosafety and degradability. Therefore, the multifunctional hydrogels provided a new approach for the design of polysaccharide-based hydrogels, and could potentially be applied in wound repair, drug delivery and other biomedical fields., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025. Published by Elsevier B.V.)

Following the implementation of "coal-to-gas conversion" policy in the Haidian District of Beijing during summer, the present comparative study was performed employing 41 PM 2.5 samples as precursors to analyze the characteristics of water-soluble inorganic ions. The concentrations of water-soluble inorganic ions in PM 2.5 were analyzed by ion chromatography, and the occurrence form of ions was characterized via time-of-flight secondary ion mass spectrometry (TOF-SIMS). Results revealed that the daily average mass concentration of PM 2.5 in Beijing during the sampling period was 94.28 ± 52.49 μg/m 3 . As compared to the winter of 2016, the average daily PM 2.5 concentration in Beijing decreased by 29 μg/m 3 in 2017 (28.2% decrease), with a remarkable decline in the number of days with pollution. During the pollution period, the concentrations of NO 3 - , SO 4 2- , and NH 4 + were significantly higher in PM 2.5 as compared to the cleaning period. The ratio of the concentrations of [NO 3 - ]/[SO 4 2- ] was greater than 1, and the contribution from mobile sources was relatively large, indicating that the implementation of the "coal-to-gas conversion" policy in Beijing has led to the reduction of SO 4 2- emissions from fixed sources, such as coal. Furthermore, TOF-SIMS analysis results showed that NH 4 + tended to exist in the form of molecular ammonium sulfate or ammonium hydrogen sulfate during the period of pollution., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)