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Long-term soil chronosequences are valuable model systems for investigating pedogenesis and investigating the process of element coupling. Here, we assessed the coupling relationships among C, Fe, and Fe-reducing bacteria (Anaeromyxobacter, Geobacter, and Shewanella) in a paddy soil chronosequence of approximately 50 to 1000 years. Soils of the chronosequence originated from tidal marsh under nearly identical landscape and climate conditions. During 1000 years of rice cultivation, soil organic carbon (SOC) contents in surface horizons (0–20 cm) increased from 10.4 to 21.8 g kg−1. In contrast, total Fe contents declined from 59.6 to 45.1 g kg−1 during the initial 50 years of paddy rice cultivation and then further decreased at a low rate of 0.004 g kg−1 soil year−1 (equivalent to 10 kg ha−1 soil year−1). Organically complexed Fe oxides (Fep) increased from 219 to 642 mg g−1 with increasing time of pedogenesis, but free total Fe oxides (Fed) and amorphous Fe oxides (Feo) declined at early stage of soil development, followed by a slow accumulation at later stages of the chronosequence. Gene copy numbers of Anaeromyxobacter and Geobacter increased from 4.6 × 105 and 3.6 × 106 copies g−1 to 3.8 × 107 and 3.6 × 107 copies g−1 dry soil with continuous paddy rice cultivation, while concurrently Shewanella gene abundance decreased gradually from 4.5 × 105 to 9.3 × 104 copies g−1 dry soil. Using structural equation modeling (SEM), different coupling relationships were observed among C, Fe, and Fe-reducing bacteria for the first 300 years of paddy chronosequence and thereafter. Overall, all Fe-reducing bacteria did not show consistent variation. With the stable microbial community and iron oxide fractions, the microbially mediated dissimilatory coupling relationship between C and Fe becomes simple during 1000 years of paddy soil development.

A porous structure on the surface of the intermetallic NiAl compound was obtained after the fibrous tungsten phase of directionally solidified NiAl-W eutectic alloys was selectively removed by pulsed polarization. Pore shape, diameter, and spacing were dependent on growth rate during directional solidification. Pore diameter and spacing decreased with increasing growth rate. Nanopores with a diameter of 220 nm and an etching depth of 45.56 μm were produced at a pulsed potential of 0.5 V and an etching duration of 72 hours. With prolonged etching, pore diameter remained unchanged and etching depth increased. The Vickers microhardness of the porous intermetallic NiAl compound (0.325 to 0.351 GPa) was lower than that of the directionally solidified NiAl-W eutectic alloys. The microhardness of the porous intermetallic NiAl compound decreased with increasing pore diameter, pore spacing, or etching depth.

The relationship between the cross-sectional shape of W fibers and kinetic undercooling in directionally solidified (DS) NiAl–W eutectic alloys was investigated. When the growth rate was less than 8 µm/s, the cross-sectional shape of W fibers was hexagonal (faceted); conversely, when the growth rate was more than 8 µm/s, their cross-sectional shape was elliptical (nonfaceted). Meanwhile, the NiAl matrix and W fibers in DS NiAl–W eutectic alloys presented a particular crystallographic orientation. The crystallographic orientation between NiAl matrix and W fibers was [ $$ \bar{1} $$ 11]NiAl//[200]W in the growth rate of 6 µm/s, and [ $$ \bar{1} $$ 11]NiAl//[ $$ \bar{1} $$ 11]W in the growth rate of 8 µm/s. A critical kinetic undercooling $$ \Delta T_{k,W}^{c} $$ can be used to predict the transition from the faceted to nonfaceted growth of W fibers in DS NiAl–W eutectic alloys. When the kinetic undercooling $$ \Delta T_{k} $$ of the W phase was less than $$ \Delta T_{k,W}^{c} $$ , the W fibers’ growth was faceted with a hexagonal shape, whereas when $$ \Delta T_{k} > \Delta T_{k,W}^{c} $$ , the W fibers exhibited nonfaceted growth with elliptical shape.

Haiyang-2A (HY-2A) is China’s first ocean dynamic environment satellite and the radar altimeter is one of its main payloads. One of the main purposes of the radar altimeter is to measure the sea surface height (SSH). The SSH determined from the altimeter range measurements includes some range and geophysical corrections. These corrections largely affect the accuracy of the SSH measurements. The range and the geophysical corrections are reprocessed and the altimeter waveforms in HY-2A sensor interim geophysical data set records (S-IGDR) are retracked from June 1, 2014 to June 14, 2014, and the accuracy of the reprocessed SSH measurements is evaluated. The methods of the range and geophysical corrections used to reprocess HY-2A altimeter data are validated by using these methods to reprocess the Jason-2 range and geophysical corrections and comparing the results with the range and geophysical corrections in Jason-2 geophysical dataset records (GDR) product. A crossover analysis is used to evaluate the accuracy of the reprocessed HY-2A SSH measurements. The standard deviation (STD) of the crossover SSH differences for HY-2A is around 4.53 cm while the STD of the SSH differences between HY-2A and Jason-2 is around 5.22 cm. The performance of the reprocessed HY-2A SSH measurements is significantly improved with respect to the SSH measurements derived from HY-2A interim geophysical dataset records (IGDR) product. The 2015–2016 El Nino has been the strongest El Nino event since 1997–1998. The range and the geophysical corrections in HY-2A IGDR are reprocessed and sea level anomalies are used to monitor the 2015–2016 El Nino. The results show that the HY-2A altimeter can well observe the 2015–2016 El Nino.

Typical up-conversion materials of NaYF4:Yb3+,Er3+ microcrystals were synthesized by a hydrothermal route using different surfactants (ethylene diamine tetraacetic acid (EDTA) and citric acid (CA)) as chelating agents. The results and analysis reveal that surfactant as a shape modifier introduced into the reaction system plays an important role in altering the crystalline structures, morphologies, and up-conversion luminescence properties of target crystals. A possible growth mechanism for NaYF4:Yb3+,Er3+ microcrystals to confirm the influence of surfactant on morphology and size was proposed on the basis of the growth rate of different crystal facets and the difference in the type of organic ligand. The luminescence mechanisms for NaYF4:Yb3+,Er3+ microcrystals as well as the correlation between the grain size, defects, morphologies and up-conversion luminescence were thoroughly analyzed.

This study examines the geomorphic evolution of Dingzi Bay, East China in response to human activity and variations in fluvial input since the 1950s. The analysis is based on data from multiple mathematical methods, along with information obtained from Remote Sensing, Geographic Information System and Global Position System technology. The results show that the annual runoff and sediment load discharged into Dingzi Bay display significant decreasing trends overall, and marked downward steps were observed in 1966 and 1980. Around 60%–80% of the decline is attributed to decreasing precipitation in the Wulong River Basin. The landform types in Dingzi Bay have changed significantly since the 1950s, especially over the period between 1981 and 1995. Large areas of tidal flats, swamp, salt fields, and paddy fields have been reclaimed, and aquaculture ponds have been constructed. Consequently, the patterns of erosion and deposition in the bay have changed substantially. Despite a reduction in sediment input of 65.68% after 1966, low rates of sediment deposition continued in the bay. However, deposition rates changed significantly after 1981 owing to large-scale development in the bay, with a net depositional area approximately 10 times larger than that during 1961–1981. This geomorphic evolution stabilized following the termination of large-scale human activity in the bay after 1995. Overall, Dingzi Bay has shown a tendency towards silting-up during 1952–2010, with the bay head migrating seaward, the number of channels in the tidal creek system decreasing, and the tidal inlet becoming narrower and shorter. In conclusion, large-scale development and human activity in Dingzi Bay have controlled the geomorphic evolution of the bay since the 1950s.

Rice paddy soils undergo pedogenesis driven by periodic flooding and drainage cycles that lead to accumulation of organic matter and the stratification of nutrients and oxygen in the soil profile. Here, we examined the effects of continuous rice cultivation on microbial community structures, enzyme activities, and chemical properties for paddy soils along a chronosequence representing 0–700 years of rice cropping in China. Changes in the abundance and composition of bacterial and fungal communities were characterized at three depths (0–5, 5–10, and 10–20 cm) in relation to organic carbon, total nitrogen, dissolved organic carbon, microbial biomass carbon/nitrogen, and activities of acid phosphatase, invertase, and urease. Both soil organic carbon and total nitrogen increased over time at all three depths, while pH generally decreased. Microbial abundance (bacteria and fungi) and invertase and urease activity significantly increased with the duration of rice cultivation, especially in the surface layer. Fungal abundance and acid phosphatase activity declined with depth, whereas bacterial abundance was highest at the 5–10-cm soil depth. Profiles of the microbial community based on PCR-DGGE of 16S rRNA indicated that the composition of fungal communities was strongly influenced by soil depth, whereas soil bacterial community structures were similar throughout the profile. Soil bioactivity (microbial abundance and soil enzymes) gradually increased with organic carbon and total nitrogen accumulation under prolonged rice cultivation. Microbial activity decreased with depth, and soil microbial communities were stratified with soil depth. The fungal community was more sensitive than the bacterial community to cultivation age and soil depth. However, the mechanism of fungal community succession with rice cultivation needs further research.

An improved absolute calibration technology based on indirect measurements was developed through two probative experiments, the performance of which was evaluated by applying the approach to in situ sea surface height (SSH) at the Tianheng Island (tidal gauge) and the satellite nadir (GPS buoy). Using Geoid/MSS (mean sea surface) data, which accounted for a constant offset between nadir and onshore tidal gauge water levels, and TMD (tidal model driver), which canceled out the time-varying offsets, nadir SSH (sea surface height) could be indirectly acquired at an onshore tidal gauge instead of from direct offshore observation. The approach extrapolated the onshore SSH out to the offshore nadir with an accuracy of (1.88±0.20) cm and a standard deviation of 3.3 cm, which suggested that the approach presented was feasible in absolute altimeter calibration/validation (Cal/Val), and the approach enormously facilitated the obtaining SSH from the offshore nadir.

A bacterial strain, designated J6(T), was isolated from activated sludge, collected from a chemical wastewater treatment system in Zhejiang Province of China. The cells stained Gram-negative, were aerobic, pale-yellow, and non-motile short rods. Phylogenetic analysis of the 16S rRNA gene sequence indicated that the closest relative of this organism was Paracoccus aminophilus KACC 12262(T) = JCM 7686(T) (97.4 % sequence similarity). Strain J6(T) grew at 10-37 °C (optimum 30 °C), at pH 6.0-8.0 (optimum pH 7.0) and with 0-5 % NaCl (optimum 3 %, w/v). The predominant cellular fatty acid found was summed feature 8(C18:1 ω7c and/or C18:1 ω6c; 82.8 %). The major respiratory quinone-detected was Q-10 and the DNA G+C content was 61.9 mol %. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine and several unknown polar lipids. Strain J6(T) showed low DNA-DNA relatedness values with P. aminophilus KACC 12262(T) (28 ± 3 %). The phylogenetic analysis, DNA-DNA hybridization, whole-cell fatty acid composition as well as biochemical characteristics allowed clear differentiation of the isolate from the other type strains of already described Paracoccus species. It is evident from the genotypic, phenotypic and chemotaxonomic analyses that strain J6(T) should be classified as a novel species of the genus Paracoccus, for which the name P. zhejiangensis sp. nov. is proposed. The type strain is J6(T) (KACC 16703(T) = CCTCC AB 2012031(T)).

A bacterial strain Pseudomonas sp. a3 capable of degrading nitrobenzene, phenol, aniline, and other aromatics was isolated and characterized. When nitrobenzene was degraded, the release of NH4 + was detected, but not of NO2 −. This result implied that nitrobenzene might have a partial reductive metabolic pathway in strain a3. However, aniline appeared as one of the metabolites during the aerobic degradation of nitrobenzene. Moreover, the appearance of 2-aminophenol during aniline degradation by strain a3 indicated that novel initial reactions existed during the degradation of nitrobenzene and aniline by strain a3. Strain a3 was immobilized in the mixed carrier of polyvinyl alcohol and sodium alginate to improve its degrading efficiency. The optimal concentrations of polyvinyl alcohol and sodium alginate in the mixed carrier were 9 and 3 %, respectively. The immobilized cells had stable degradation activity and good mechanical properties in the recycling tests. The immobilized cells also exhibited higher tolerances in acidic (pH 4–5) and highly saline (10 % NaCl) environments than those of free cells. The biodegradation of nitrobenzene mixed with aniline and phenol using immobilized cells of Pseudomonas sp. a3 was also greatly improved compared with those of free cells. The immobilized cells could completely degrade 300 mg L−1 nitrobenzene within 10 h with 150 mg L−1 aniline and 150 mg L−1 phenol. This result revealed that the immobilized cells of Pseudomonas sp. a3 could be a potential candidate for treating nitrobenzene wastewater mixed with other aromatics.