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Amino acids (AAs) are involved in the global nitrogen cycle and are important components of nitrogenous organic aerosols. Protein and free amino acid (FAA) concentrations in total suspended particulate (TSP) and their major emission sources were investigated in spring and autumn at Mount Tai (Mt. Tai) on the North China Plain and the nearby city named Liaocheng. There were significant spatial and seasonal differences in protein and FAA concentrations, with rainfall producing lower concentrations. For chiral isomers of AAs, there were significant diurnal differences in D/L-Methionine (Met), which was probably due to FAA source differences caused by regional valley winds and background winds. The high D/L-aspartic acid (Asp) and D/L-glutamine (Glu) concentrations may be indicative of the important contributions of chunk and honeycomb coal combustion. Stable nitrogen isotope analyses revealed that plant debris, soil dust, and biomass burning were important sources of glycine (Gly). Biomass burning, as well as chunk and honeycomb coal combustion, produced large amounts of L-arginine (Arg). Soil dust was the dominant source of FAAs for both Mt. Tai and Liaocheng, while biomass burning contributed more in autumn, and the proportional contribution of plant debris increased in spring. [Display omitted] • Molecular compositions and sources of atmospheric free amino acids in mountainous and urban aerosols were compared. • D/L ratio and stable nitrogen isotope analyses were used together to determine the source of particulate free amino acids. • Mechanism of regional transport of particulate free amino acids in mountainous area is proposed. [ABSTRACT FROM AUTHOR]

Recent researchers show that the shell structure and truss structure are emerging categories of light weight structure with unique mechanical properties and high customization potential, but they are difficult to manufacture by traditional methods. Inspired by the diving bell of water spider, the reticulated shell structure designed in this work combines the characteristics of the truss structure and the shell structure, and is fabricated by laser powder bed fusion (LPBF). The effect mechanism of strut angle on the manufacturability, compressive behaviors, energy absorption property, stress distribution, and fracture morphology were studied by experiment and simulation methods. The results showed that the relative densities of reticulated shell structures increased with the increase of strut angle, which was due to the existence of a large proportion of overhang structures in the reticulated shell structures. The compressive load-displacement curves of all reticulated shell structures showed a similar trend, including three stages, which were elasticity, subsidence, and densification. The reticulated shell structure with the strut angle of 75° had the highest specific energy absorption and energy absorption capacity. Finite element simulation results revealed that, with the change of the strut angle, the stress concentration in the reticulated shell structure significantly changed and directly affected the compression behavior of structures. The structure with the strut angle of 75° exhibited the lowest stress concentration level at key locations, leading to the best compressive behavior among structures. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM), also known as 3D printing, has greatly promoted the development of lattice structures with complex configurations. However, these lattice structures usually consist of periodically arranged nodes and struts. Here, inspired by the three-dimensional crystalline microstructure of selective laser melted (SLM) Al–Si alloy, a type of novel cellular structure with irregular nodes and struts was designed and fabricated by the SLM process with Al–Si alloy powder. The as-fabricated cellular structures were multi-scale materials from nano- to macro-scale. Electron backscatter diffraction (EBSD) analysis revealed that compared with the edge region, the central region of the struts had larger grain size, dominant (001) grain orientation, and worse toughness. Most importantly, compared with the regular lattice structures, the novel cellular structures brought about maximum 32.8% and 38.3% improvement in volumetric energy absorption W v and specific energy absorption W s , respectively. Furthermore, the finite element simulation was employed to reveal the stress distribution and energy absorption mechanism of cellular components during compression. Finally, the different fracture modes between the edge and central regions of the struts were investigated. The Al–Si crystalline microstructure inspired cellular structures have potential applications in biomaterials, vibration and thermal insulation. [ABSTRACT FROM AUTHOR]

To examine whether historical fish bones can record the magnitude of heavy metal pollution, we analyzed up to 700 years old fish bone remains extracted from an ornithogenic sediment profile on Nandao Island, South China Sea. Bulk sediments and subfossil fish bones were analyzed for elemental and mineralogical composition, as well as stable carbon and nitrogen isotopes. The results showed that pre-1850 CE fish bones experienced significant diagenesis, and could not be used to reconstruct historical record of heavy metal pollution. Fish bone diagenesis was mainly attributed to the erosion from guano in sediment profile. In contrast, the fish bones from in post-1850 CE time were well preserved and could provide useful information on historical pollution loads over the past 160 years. Since 1850 CE, relatively high concentrations of heavy metals from anthropogenic sources, especially Zn, were recorded in fish bone subfossils on Nandao Island, South China Sea. Unlabelled Image • FT-IR analysis indicated that fish bones before 1850 CE were poorly preserved. • Diagenesis in fish bones possibly led to increase in Cu and Hg concentration. • Diagenesis was affected by the erosion of guano in the ornithogenic sediments. • Anthropogenic pollution especially Zn was detected in fish bones since 1850 CE. [ABSTRACT FROM AUTHOR]

The nitrogen (N) utilization strategy of plants has become a topic of interest within the field of phytoecology. However, few studies have considered N cycling on coral island ecosystems from the perspective of their evolution. The aim of this study was to test the impacts of biological transport by seabirds, on the sources and uses of N by plants, and pathways of N cycling in soil–plant ecosystems on coral islands. A series of eight coral islands were investigated, five of which were affected to a varying extent by seabirds. The total phosphorus (TP) concentration from avian sources and the δ 15 N values of total nitrogen (TN) and inorganic nitrogen (IN: NH 4 + -N, and NO 3 − -N), δ 18 O of NO 3 − -O, in soils were determined, as well as proxies in plant leaves of two dominant plant species, including TN, the carbon/nitrogen ratio (C/N), and δ 13 C and δ 15 N values. The results show that, with an increase of TP, the TN and IN content, and δ 15 N values in soils all increased. Plant C/N and δ 15 N values decreased and increased, respectively, as the soil N content increased. When the TN content of the soil was low, the δ 15 N value in plant leaves was similar to that in soil NO 3 − , but was much lower than that in soil NH 4 + . When the soil TN content was high, the δ 15 N values were similar. Both plants and soil were probably N-limited prior to seabird colonization, with the N source on the barren coral islands originating primarily from atmospheric deposition. With seabird guano input and subsequent pedogenesis, the source of N switched to guano. Under these conditions, most of the N utilized by plants originated from NH 4 + , while nitrate is dominant for non-seabirds islands. Seabird activities have played a key role in the N dynamics of soil–plant ecosystems at coral islands. [ABSTRACT FROM AUTHOR]

Marine sediments have been frequently used to reconstruct the records of environment change and human activities. We collected four sediment cores from Wanquan River estuary and the eastern continental shelf of Hainan Island in the South China Sea, and analyzed the down-core physical and chemical properties of sub-samples. Based on 210 Pb dating, the longest core had a record of the most recent 200 years, while the other three profiles were slightly younger. The results show that both the TOC/TN ratios and fossil fuel-corrected organic δ 13 C of marine sediments for all four cores remained relatively constant before 1950 AD, indicating relatively stable sedimentary material sources. However, after 1950 AD, the TOC/TN ratios and organic δ 13 C in all four sediment cores displayed decreasing and increasing trends, respectively, indicating that the proportion of marine-derived material increased, whereas the land-derived materials that were mainly transported by the Wanquan River decreased. This is consistent with the obvious decrease in runoff and sediment discharges of the Wanquan River due to the increase in human activities, including industrial and agricultural production, and domestic water use in Hainan Island since 1950 AD. Therefore, we suggest that environmental changes on the land were recorded by changes in the source material of marine sediments collected from coasts and estuaries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Massive organic nitrogen excreted by penguin are input into ice-free soils in Antarctica. • Guano-affected soil organic nitrogen tends to be oxidized into relatively stable molecules. • A detailed schematic diagram of the Antarctic nitrogen cycle is proposed. Organic nitrogen (ON) is an important participant in the Earth's N cycle. Previous studies have shown that penguin feces add an abundance of nutrients including N to the soil, significantly changing the eco-environment in ice-free areas in Antarctica. To explore the molecular transformation of ON in penguin guano-affected soil, we collected guano-free weathered soil, modern guano-affected soil from penguin colonies, ancient guano-affected soil from abandoned penguin colonies, and penguin feces from the Ross Sea region, Antarctica, and Fourier transform ion cyclotron mass spectrometry (FT-ICR MS) was used to investigate the chemical composition of water-extractable ON. By comparing the molecular compositions of ON among different samples, we found that the number of ON compounds (>4,000) in weathered soil is minimal, while carboxylic-rich alicyclic-like molecules (CRAM-like) are dominant. Penguin feces adds ON into the soil with > 10,000 CHON, CHONS and CHN compounds, including CRAM-like, lipid-like, aliphatic/ peptide-like molecules and amines in the guano-affected soil. After the input of penguin feces, macromolecules continue to degrade, and other ON compounds tend to be oxidized into relatively stable CRAM-like molecules, this is an important transformation process of ON in guano-affected soils. We conclude the roles of various forms of ON in the N cycle are complex and diverse. Combined with previous studies, ON eventually turns into inorganic N and is lost from the soil. The lost N ultimately returns to the ocean and the food web, thus completing the N cycle. Our study preliminarily reveals the molecular transformation of ON in penguin guano-affected soil and is important for understanding the N cycle in Antarctica. [ABSTRACT FROM AUTHOR]

Highlights: [•] RE addition in the alloys causes the formation of Al2RE/Al3RE. [•] RE addition can improve the RT tensile properties of the alloys. [•] The mechanical properties of the alloys after homogenization become worse. [Copyright &y& Elsevier]

Abstract: The aim of this study is to investigate the influence of extractives on the yield and composition of oil obtained from biomass samples (Artemisia ordosica, corn stalk and wheat straw). Direct deoxy-liquefaction experiments of original and extracted biomass were performed at certain temperature in a stainless steel tubular reactor. Benzene–alcohol solvent extraction had significant effect on the product distribution of biomass, especially on the yield and composition of the product oils. The oil yield of original biomass and alkane content in the oil were in the range of 5.44–9.27% and 8.23–23.64%, while decreased to 3.83–4.45% and 1.07–6.03% for the extracted biomass. This study concludes that most of alkanes in the oil mainly derive from the decomposition of triglyceride and hydrocarbon existed in the extractives of biomass. The results might be helpful to study the origin of alkanes and benzene derivatives in the oil obtained from biomass via direct deoxy-liquefaction. [Copyright &y& Elsevier]

Poplar leaves, poplar bark and poplar wood were deoxy-liquefied directly in an air-proof stainless steel reactor at different temperatures. The oils from leaves at 350°C, from bark at 400°C and from wood at 450°C, at which the liquid product yields were the maximum, were analyzed by GC–MS. The oils obtained from three parts of poplar tree were quite different from each other in the relative contents of their compositions. The oil from leaves was rich in hydrocarbons (alkanes: C7–C29; aromatics) and poor in phenolics, while oil from wood was rich in phenolics and poor in hydrocarbons. The oil from bark was moderate. Relative contents of hydrocarbons in the leaves oil were as high as 60.01% but decreased to 29.71% in bark oil and 11.43% in wood oil. GC analysis of gases and FT-IR, GC–MS and elemental analysis of oils were performed in this study. [Copyright &y& Elsevier]

Lipids are important biogenic markers to indicate the sources and chemical process of aerosol particles in the atmosphere. To better understand the influences of biogenic and anthropogenic sources on forest aerosols, total suspended particles (TSP) were collected at Mt. Changbai, Shennongjia, and Xishuangbanna that are located at different climatic zones in northeastern, central and southwestern China. n- Alkanes, fatty acids and n- alcohols were detected in the forest aerosols based on gas chromatography-mass spectrometry. The total concentrations of aliphatic compounds ranged from 15.3 ng m−3 to 566 ng m−3, and fatty acids were the most abundant (44–95%) followed by n- alkanes and n- alcohols. Low molecular weight- (LFAs) and unsaturated fatty acids (UnFAs) showed diurnal variation with higher concentrations during the nighttime in summer, indicating the potential impact from microbial activities on forest aerosols. The differences of oleic acid (C 18:1) and linoleic acid (C 18:2) concentrations between daytime and nighttime increased at lower latitude, indicating more intense photochemical degradation occurred at lower latitude regions. High levels of n- alkanes during daytime in summer with higher values of carbon preference indexes, combining the strong odd carbon number predominance with a maximum at C 27 or C 29 , implied the high contributions of biogenic sources, e.g., higher plant waxes. In contrast, higher concentrations of low molecular weight n- alkanes were detected in winter forest aerosols. Levoglucosan showed a positive correlation (R2 > 0.57) with high- and low molecular weight aliphatic compounds in Mt. Changbai, but such a correlation was not observed in Shennongjia and Xishuangbanna. These results suggest the significant influence of biomass burning in Mt. Changbai, and fossil fuel combustion might be another important anthropogenic source of forest aerosols. This study adds useful information to the current understanding of forest organic aerosols at different geographical locations in China. [Display omitted] • Seasonal differences in impact of biogenic/anthropogenic sources on forest aerosols. • The photodegradation of unsaturated fatty acids was more severe in lower latitudes. • Both biomass burning and fossil fuel combustion contributed to the Mt. Changbai aerosols. • Different patterns of lipids in forest aerosols at different locations in China. [ABSTRACT FROM AUTHOR]

Abstract: The relationships between morphology and proton conduction for Nafion membranes and hydrocarbon-type proton exchange membranes, namely, sulfonated poly(arylene ether ether ketone) (S-PEEK) and sulfonated poly(arylene ether sulfone) (S-PES), were investigated by small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM). The direct simultaneous observation of surface morphology and active regions of proton conduction on membranes by combined high-resolution AFM phase imaging and an electrochemical technique at controlled humidity provided significant morphological information, particularly for the hydrocarbon-type membranes that exhibit few or no features on SAXS profiles. For the Nafion membranes, the active proton paths became denser and congregated with each other at over 60% RH, resulting in the formation of well-connected networks. For the hydrocarbon-type membranes, however, only the relatively small and dispersed proton paths were observed, which showed no significant change even as water content increased. We have demonstrated that the differences in microscopic morphology between the Nafion and hydrocarbon-type membranes are associated with the differences between their macroscopic proton conductivities. [Copyright &y& Elsevier]

Low molecular weight organic compounds are ubiquitous in the atmosphere. However, knowledge on their concentrations and molecular distribution in fresh snow remains limited. Here, twelve fresh snow samples collected at eight sites in China were investigated for dicarboxylic acids and related compounds (DCRCs) including oxocarboxylic acids and α-dicarbonyls. Dissolved organic carbon (DOC) concentrations in the snow samples ranged from 0.99 to 14.6 mg C L−1. Concentrations of total dicarboxylic acids were from 225 to 1970 μg L−1 (av. 650 μg L−1), while oxoacids (28.3–173, av. 68.1 μg L−1) and dicarbonyls (12.6–69.2, av. 31.3 μg L−1) were less abundant, accounting for 4.6–8.5% (6.2%), 0.45–1.4% (0.73%), and 0.12–0.88% (0.46%) of DOC, respectively. Molecular patterns of dicarboxylic acids are characterized by a predominance of oxalic acid (C 2) (95.0–1030, av. 310 μg L−1), followed by phthalic (Ph) (9.69–244, av. 69.9 μg L−1) or succinic (C 4) (23.8–163, av. 63.7 μg L−1) acid. Higher concentrations of Ph in snow from Beijing and Tianjin than other urban and rural regions suggest significant emissions from vehicular exhausts and other fossil fuel combustion sources in megacities. C 2 constituted 40–54% of total diacids, corresponding to 1.5–2.6% of snow DOC. The total measured DCRCs represent 5.5–10% of snow DOC, which suggests that there are large amounts of unknown organics requiring further investigations. The spatial distributions of diacids exhibited higher loadings in megacities than rural and island sites. Molecular distributions of diacids indicated that the photochemical modification was restrained under the weak solar radiation during the snow events, while anthropogenic primary sources had a more significant influence in megacities than rural areas and islands. • Dicarboxylic acids and related compounds were analyzed in urban, rural and island snow samples. • Total measured dicarboxylic acids and related compounds represent 5.5–10% of snow DOC. • High abundance of phthalic acid in urban snow suggests strong emission from fossil fuel combustion. [ABSTRACT FROM AUTHOR]

In current work, we have used fiber laser welding (FLW) technology to manufacturing the Ti–6Al–4V (TC4) and Inconel 718 (IN718) bimetallic structure and to prevent the formation of brittle phases via Cu/Ta multi-interlayer. The results of this study showed that Cu/Ta multi-interlayer was very effective in preventing the formation of continuous brittle intermetallic layers of Ti–Ni and Ti–Cu. The good metallurgical bonds were presented at these interfaces between TC4 and IN718. As a result, the joints with gradational structure, i.e. TC4| (α+β Ti, Ta) ss | (β Ti, Ta) ss | Ta(s, s)+ (Cu(s, s)+ Ta(s, s)+ Ti 3 Ni 4)| Cu(s, s)+ (Cu(s, s)+ Ta(s, s))| Ni(Ta, Fe, Cr) ss | IN718 can be formed, which can contribute high tensile strength of joints with the value of 396 MPa. •In this paper, we use a new Cu/Ta multi-interlayer layer for fiber laser welding TC4 and IN 718. •The formation of continuous brittle intermetallic layers of Ti–Ni and Ti–Cu is effectively prevented. The tensile strength of the bimetallic structure with the Cu/Ta multi-interlayer was 396 MPa, which reached that of the 42.6% and 45.8% of the tensile strength of TC4and IN718, respectively. •In the present work, defect-free, dissimilar FLW of the bimetallic structure was successfully achieved by using Cu/Ta multi-interlayer. The typical microstructure of joint is TC4| (α+β Ti, Ta)ss| (β Ti, Ta)ss| Ta(s, s)+ (Cu(s, s)+ Ta(s, s)+ Ti3Ni4)| Cu(s, s)+ (Cu(s, s)+ Ta(s, s))| Ni(Ta, Fe, Cr)ss| IN718. [ABSTRACT FROM AUTHOR]

• Adsorption capacities of Fe/S-BC are improved after Fe/S co-doping. • Fe/S-BC has a high adsorption capacity for As(III) and Pb(II). • The presence of Pb(II) decreased the adsorption capacity of As(III). • The synergistic effects on Pb adsorption were observed in combined pollutants. Simultaneous elimination of As(III) and Pb(II) from wastewater is still a great challenge. In this work, an iron-sulfur codoped biochar (Fe/S-BC) was successfully fabricated in a simplified way and was applied to the remediate the co-pollution of As(III) and Pb(II). The positive enthalpy indicated that the adsorption in As-Pb co-pollution was an endothermic reaction. The mechanism of As(III) removal could be illustrated by surface complexation, oxidation and precipitation. In addition to precipitation and complexation, the elimination mechanism of Pb(II) also contained ion exchange and electrostatic interactions. Competitive and synergistic effects existed simultaneously in the co-contamination system. The suppression of As(III) was ascribed to competitive complexation of the two metals on Fe/S-BC, while the synergy of Pb(II) was attributed to the formation of the PbFe 2 (AsO 4) 2 (OH) 2. Batch experiments revealed that Fe/S-BC had outstanding ability to remove As(III) and Pb(II), regardless of pH dependency and interference by various coexisting ions. The maximum adsorption capacities of the Fe/S-BC for As(III) and Pb(II) were 91.2 mg/g and 631.7 mg/g, respectively. Fe/S-BC could be treated as a novel candidate for the elimination of As(III)-Pb(II) combined pollution. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Co-deoxy-liquefaction of biomass and vegetable oil was investigated under the conditions of different temperatures (350–500°C) and residence time as well as catalyst using HZSM-5. Results suggested low temperature was favorable for the formation of diesel-like products, while high temperature caused more gasoline-like products. By the addition of HZSM-5, at 450°C alkanes content of the obtained oil with low oxygen content of 2.28%, reached a maximum of 56.27%, resulting in the highest HHV of 43.8MJkg−1. High temperature favored cracking activity of HZSM-5 which reduced the char formation and contributed to the removal of carbonyl. Compared to temperature, the effect of residence time on products was relatively less; experiments indicated the optimum residence time was 15min at which obtained oil with the highest yield of 17.78%, had better properties. Preliminary analysis of mechanisms showed biomass provided hydrogen for vegetable oil, facilitating hydrogenation of Cf vegetable oil. [ABSTRACT FROM AUTHOR]

Black carbon (BC) plays a vital role in atmospheric environment and climate change. Temporal variations and transport pathways of BC in Xiamen, China with the impacts of synoptic circulation were investigated in 2014 with Aethalometer. Annual mean BC concentration was 4270 ng m−3. BC exhibited clear diurnal (seasonal) variations, with the maximum of 6182 (4755) ng m−3 at 6:00 (in spring) and minimum of 2847 (3774) ng m−3 at 13:00 (in summer). Conditional probability function analysis indicated that high BC concentrations were associated with northwesterly winds with low wind speed. Air masses originating from the East China Sea and passing along with East China Coast had the highest BC concentrations. Potential source contribution function and concentration weighted trajectory analysis suggested that major sources for BC included the surrounding region, southwestern Fujian and eastern Guangdong to the southwest, Hubei, Hunan and Jiangxi to the northwest, the East China Sea and the South China Sea. Of the nine synoptic circulation patterns, three cyclone-related patterns were associated with low BC concentrations and small biomass burning (BC bb) contributions. Of the six anticyclone-related patterns, the three cold-high circulations around winter were associated with moderate BC concentrations and large BC bb contributions. The two cold-high patterns in spring and autumn were associated with high BC concentrations and small BC bb contributions, while the warm-high pattern was associated with moderate BC concentration and small BC bb contribution. The findings provide insights into the transport mechanisms of BC with the impacts of synoptic pattern in China. • One year on-line observation of BC was conducted in Western Taiwan Strait in China. • Originations and transport pathways of BC were investigated with CPF, PSCF and CWT. • Impacts of synoptic circulations on BC from different source sectors were analyzed. [ABSTRACT FROM AUTHOR]

The planting of salt-tolerant plants is regarded as the one of important measurements to improve the saline–alkali lands. The outstanding biological properties of JUNCAOs have made them candidates to improve and utilize saline–alkali lands. At present, little attention has been paid to developing a non-destructive and high throughput approach to evaluate the salt tolerance of JUNCAO. To close the gaps, three typical JUNCAOs (A.donax. No.1, A.donax. No.5 and A.donax. No.10) were evaluated by combining prompt chlorophyll a fluorescence (ChlF) with hyperspectral spectroscopy (HS). The results showed that salt stress reduced relative stem growth, water content, and total chlorophyll content but enhanced the malondialdehyde (MDA) content. It caused a significant change in chlorophyll a fluorescence kinetics with an appearance of L-, K- and J-band, implying damaging energetic connectivity between PSII units, uncoupling of the oxygen evolving complex (OEC) and inhibition of the Q A −reoxidation. The negative impact of salt stress on JUNCAOs increased with the increasing level of salt concentration. Effect on spectral reflectance in the in the visible region with shifts on red edge position (REP) and blue edge position (BEP) to shorter wavelength was also found in salt stress plants. Combining principal component analysis (PCA) with the membership function method based on spectral indices and JIP-test parameters could well screen JUNCAOs salt tolerant ability with the highest for A.donax. NO.10 but lowest for A.donax. NO.1, which was the same as that of using conventional approach. The results demonstrate that prompt ChlF coupling with HS could provide potentials for non-invasively and high-throughput phenotyping salt tolerance in JUNCAOs. • Salt damaged energetic connectivity, oxygen evolving complex and Q A − reoxidation. • Salt induced shifts on red and blue edge positions to shorter wavelength. • Prompt ChlF and HS have potentials for high-throughput phenotyping salt tolerance. [ABSTRACT FROM AUTHOR]

Ornithogenic sediments are rich in toxic As (arsenic) compounds, posing a potential threat to local ecosystems. Here we analyzed the distribution of As speciation in three ornithogenic sediment profiles (MB6, BI and CC) collected from the Ross Sea region, East Antarctica. The distributions of total As and total P (phosphorus) concentrations were highly consistent in all three profiles, indicating that guano input is a major factor controlling total As distribution in the ornithogenic sediments. The As found in MB6 and CC is principally As(V) (arsenate), in BI As(III) (arsenite) predominates, but the As in fresh guano is largely composed of DMA (dimethylarsinate). The significant difference of As species between fresh guano and ornithogenic sediment samples may be related to diagenetic processes after deposition by seabirds. Based on analysis of the sedimentary environment in the studied sediments, we found that the redox conditions have an obvious influence on the As speciation distribution. Moreover, the distributions of As(III) and chlorophyll a in the MB6 and BI profiles are highly consistent, demonstrating that aquatic algae abundance may also influence the distribution patterns of As speciation in the ornithogenic sediments. [ABSTRACT FROM AUTHOR]

• Rainwater DOM along the yangtze river were characterized by optical properties and FT-ICR MS. • Natural and anthropogenic emissions and climatic conditions shaped the chemodiversity of rainwater DOM. • Biogenic secondary organic compounds widely contributed to rainwater DOM along the Yangtze River Basin. Rainwater dissolved organic matter (DOM) plays an important role in the biogeochemical cycle and evolution of organic matter in the land-atmosphere interface. To better understand their sources and molecular composition in the atmosphere, rainwater samples were collected at six different locations along the Yangtze River Basin. Based on the application of a combined approach including excitation-emission matrix (EEM) fluorescence and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), various sources (terrestrial, anthropogenic, and autochthonous sources) of rainwater DOM were revealed. Results show that the derivatives of biogenic volatile organic compounds were widely distributed and contributed to rainwater DOM along the Yangtze River Basin. In the up-river city Batang, rainwater DOM was affected by the long-range atmospheric transport due to the Indian summer monsoon. Lijiang, a city on the southeastern edge of Tibetan plateau, was related to strong local biomass burning. The industrial cities of Panzhihua and Luzhou showed large differences in organic composition due to distinct industrial types. Fuling, a district in Chongqing Municipality, was significantly contributed by aged organics from biomass burning. While rainwater DOM in Shanghai, a coastal megacity, contained a high fraction of sea spray organics. Further, more than 70% of rainwater DOM molecules are associated with 36 typical transformation mechanisms during rainwater-scavenging processes, e.g., oxidation reactions, dealkylation and decarboxylation. Our study demonstrates that local natural and anthropogenic emissions and climatic conditions strongly shaped the chemodiversity and possible precursor-product pairs of rainwater DOM along the Yangtze River Basin, which helps to better understand the biogeochemical cycles of organic matter in a large-scale watershed under the influence of human activities. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Since the post-casting treatments influence the water entrapped in polymeric matrix and consequently its proton conductivity, an evaluation of annealing at 200°C and acid treatments was conducted on previously developed composite s-PEEK (1.55mequiv.g−1) membranes, containing a commercial aminopropyl-functionalised silica. DSC, WAXS, SEM–EDX and laser microscope measurements carried out on membranes swollen at different temperatures highlighted different membrane properties depending on post-casting treatments. It was found that composite membranes have different structural and morphological characteristics than pristine polymer membranes. The silica distribution was modified when different treatments are used. The state of water changed when silica was inserted into the membranes. Actually, contrary to the pristine membranes the presence of freezable water was revealed at temperature lower than 80°C. The proton conductivity was also affected by the presence and the amount of water trapped into the membranes and was particularly influenced by the post-casting treatments. The silica introduction reduced the swelling effect and improved the robustness of the membranes even if a higher water content in the freezable state was observed. Acid treatment leads to significant improvement in membrane properties, but the present work shows that annealing before acid treatment can affect the membrane morphology more strongly than other treatments resulting in a much better fuel cell performance. [Copyright &y& Elsevier]

Abstract: Pyrolysis of a mixture of Fe phthalocyanine and phenolic resin (FePc/PhRs) was studied to clarify the details of the preparation protocol of nitrogen-doped carbon-based materials for cathode catalysts in polymer electrolyte membrane fuel cells. TEM images show that nanoshell carbon is formed by the pyrolysis of FePc/PhRs in the temperature range of 600–800°C. The optimum pyrolysis temperature for the FePc/PhRs mixture was 600°C, where moderate conductivity and high nitrogen content of the prepared carbon were both satisfied. This catalyst showed a promising fuel cell performance with 1.01V open-circuit voltage and 0.33Wcm−2 maximum output, at 0.2MPa absolute pressure and 80°C. A detailed study of the carbonization process suggests that the presence of Fe species during carbonization process contributes to higher nitrogen content and growth of nanoshell structure of the resulting carbon. [Copyright &y& Elsevier]

The variations in physicochemical properties of airborne particles collected during a typical transition from haze to dust were investigated using single particle analysis with transmission and scanning electron microscopes combined with online measurement of chemical compositions of airborne particles in Beijing in February 2013. The transition was divided into three phases based on the weather condition. During haze pollution (Phase 1), gaseous and particle pollutants enhanced gradually. Results from single particle analysis showed that more coatings and more anthropogenic elements (e.g., S) appeared on the surface of fine and coarse particles, which was probably caused by efficient aqueous-phase reactions under high humidity (70%) condition. Phase 2 was dust intrusion episode. PM 10 reached over 1000 μg m−3. Larger fractions of mineral particles and bare-like soot particles were observed in fine particles, while the fraction of secondary particles with coatings decreased. The proportion of black carbon in submicron particles also increased. Photochemical oxidation in gas phase likely dominated in secondary formation under high O 3 concentration. After the dust episode (Phase 3), secondary formation enhanced obviously. Soot aged quickly and had a larger mode of 0.45 μm than the other phases. The size modes of airborne fine particles during Phases 1 and 3 were 0.35 μm, which were a bit larger than that during Phase 2 (0.24 μm). These results indicate that dust plumes accompanied with strong wind brought mineral particles in both fine and coarse modes and freshly emitted particles with smaller sizes, and swept away pre-presence air pollutants. This study could provide detailed information on the physicochemical properties of airborne particles during typical severe pollution processes in a short time. Such short-term change should be taken into account in order to more accurately assess the environmental, climatic and health-related effects of airborne particles. Unlabelled Image • A typical transition from haze to dust was observed in Beijing. • Airborne particles were analyzed by single particle analysis combined with online aerosol mass spectrometry. • The dust plume brought mineral particles and freshly emitted particles and swept away secondary particles. • Photooxidation contributed secondary formation in dust episode while aqueous reaction dominated in haze episode. • The dust plume and local polluted air mixed slightly in the transition period. [ABSTRACT FROM AUTHOR]

• The inducing ligand strategy with high protein affinity have been used in protein assembly. • Hierarchical self-assembly of ConA with inducing ligand. • Kinetic study of the self-assembly process by tuning the protein/ligand ratio. Proteins self-assemble into kinds of sophisticated architectures is ubiquitous in nature. Construction of these nanostructures in laboratory is helpful for understanding this physiological process and obtaining new functional materials. Although current state-of-the-art strategies have been developed, effective methods to regulate the process are still deficient. Herein, hierarchical self-assembly of Con A induced by a new designed oligosaccharide inducing ligand (RhB- tri Man) was reported. The self-assembly of Con A can be regulated in the presence of transition metal ion Mn2+ due to the opening of spirolactone of RhB, and the assembly process can be further regulated by changing the molar ratio of ligands to proteins. [ABSTRACT FROM AUTHOR]

Primary biological particles are an important subset of atmospheric aerosols. They have significant impacts on climate change and public health. Tianjin is a coastal megacity in the North China Plain, which is affected by both anthropogenic activities and marine air masses. To study the abundance and dynamic change of bioaerosols in Tianjin, fluorescent biological aerosol particles (FBAPs) in Tianjin were investigated by a wideband integrated bioaerosol sensor (WIBS-4A) in terms of number concentrations and size distributions in summer (11th –25th August 2018). Meanwhile, total suspended particles were collected and analyzed for chemical compounds to identify potential sources of bioaerosols. WIBS data showed that fluorescent biological particles exhibited two peaks at sunrise (~7:00) and in the evening (~20:00), which were probably caused by the enhancement of fungal spores and bacteria. Three rain events occurred during the observation period. Precipitation enhanced the abundance of biological particles, which were likely released from vegetation leaves, resuspended from soil surfaces, and/or carried by raindrops from high altitudes. The abundance of biological particles showed no significant correlation with Na+ (r = −0.17), indicating the air masses from marine areas carried limited biological particles compared to those from continental areas. Unlabelled Image • Real-time fluorescent aerosol particles (FAPs) were characterized in the coastal megacity Tianjin in summer. • Abundance of FAPs increased during precipitation, while that of non-FAPs decreased. • The size distribution of FAPs was dominant in 1–3 μm while non-FAPs peaked at 1 μm during precipitation. [ABSTRACT FROM AUTHOR]

• We investigated organic marker compounds in PM 2.5 over Mt. Emei at a molecular level. • Higher concentrations of primary organic aerosols in the daytime were influenced by the valley breezes. • The contribution of biomass burning enhanced in the daytime during the pollution episodes. Organic molecular composition of fine aerosols in the free troposphere is poorly understood. Here, PM 2.5 (particles with aerodynamic diameters ≤ 2.5 μm) samples were collected at the summit of Mt. Emei (3080 m a.s.l.) in the Southwestern China on a daytime and nighttime basis during summer 2016 (June–July). The samples were analyzed by solvent-extraction followed by derivatization and gas chromatography/mass spectrometry (GC/MS). Four classes of organic compounds, i.e. n -alkanes, fatty acids, saccharides and lignin/resin acids were measured quantitatively. Fatty acids were found to be the most abundant species with an average concentration of 401 ± 419 ng m−3 (range 25.7–1490 ng m−3) in the daytime, similar to the average concentration at night (399 ± 447 ng m−3, 19.6–1970 ng m−3). However, the concentrations of biomass burning tracers (e.g., levoglucosan), primary biological aerosol tracers (e.g., mannitol and arabitol) and low molecular weight n -alkanes derived from fossil fuel combustion in daytime samples were obviously higher than those in nighttime samples. The results suggest that valley breezes transported a large number of aerosols and their precursors from the ground surface to the summit of Mt. Emei in the daytime. Estimated with tracer-based methods, the contributions of biogenic primary sources (plant debris, fungal spore, and biomass burning) to organic carbon was in the range of 3.28–83.5% (22.0 ± 17.5%) in the daytime and 3.45–37.4% (10.9 ± 8.97%) at night. As the largest contributor, biomass burning was an important anthropogenic/natural source of aerosol particles in the free troposphere over Mt. Emei. Valley/mountain breeze is an important constraint to the temporal variations in organic aerosols over Mt. Emei. [ABSTRACT FROM AUTHOR]

Silicon-based anode for lithium-ion batteries (LIBs) has attracted much attention due to its high theoretical capacity, low operating potential and abundant resources. However, the large volume expansion/shrink during the lithiation/delithiation process induces extreme damage to the electrode microstructure. The resulting failure of electrical contact between silicon and current collector will severely deteriorate the cycling stability. Herein, a three-dimensional nano-Si/N-doped carbon network was obtained by a facile approach with NaCl templates. The N-doped carbon network not only significantly improves the electronic conductivity, but also ensures a valid electrode microstructure through a highly elastic carbon framework. Additionally, a two-dimensional nano-Si/N-doped carbon sheet was prepared without NaCl templates, revealing the boosting action of NaCl templates in the microstructure adjustment from low dimension to spatial crosslinking. The optimal three-dimensional nano-Si/N-doped carbon composite can deliver a high specific capacity of 1396 mAh g−1 with a capacity retention of 84.3% after 100 cycles at 200 mA g−1. This study provides effective guidance for novel Si-based anode design to achieve high-energy LIBs with excellent cycling stability. Image 1 [ABSTRACT FROM AUTHOR]