Search

• A SLM-assisted ns-laser processing technique is proposed for fabricating large-area, uniform, and well-arranged periodic structures on Cr films. • 2. For 1000-nm thick Cr films, the processed surface exhibits hybrid periodic microstructures comprised by modulated grating (MG) and laser induced periodic surface structures (LIPSS), that is, MG-LIPSS, which displays vivid anisotropic structural colors. • 3. For 200-nm thick Cr films, the processed hybrid structures are a combination of MG and cracks, that is, MGC, which can be utilized as a transmission grating with diffraction effects. An effective technique for preparing different hybrid periodic structures on chromium (Cr) films of different thicknesses using a 1064-nm nanosecond laser assisted by spatial light modulator (SLM) is proposed. For 1000-nm Cr films, by combining periodic modulated grating (MG) patterned by SLM with laser-induced periodic surface structures (LIPSS), regular dual-scale MG-LIPSS can be fabricated, with the morphological characteristics controlled by laser fluence, effective pulse number, and MG period. Due to diffraction effects of MG and LIPSS, MG-LIPSS patterned surfaces exhibit vivid anisotropic structural colors. In contract to MG-LIPSS, complex periodic structures consisting of MG and cracks (MGC) are fabricated on 200-nm Cr films due to the more significant thermal stress of a thinner film. Although the cracks of MGC distributed randomly, MGC show a long-range order characteristic with a certain transmittance, which can be utilized as a transmission grating with diffraction effects. These results demonstrate that optical field modulated laser machining based on SLM offers an efficient, cost-effective, and controllable method for fabricating large-area periodic structures on Cr films. Moreover, variations in film thickness can be employed to explore hybrid microstructures with specific properties, and thus utilized in diverse applications, such as optical components and anti-counterfeiting measures. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of adaptive tracking control for a class of nonlinear multi-input and multi-output (MIMO) state-constrained systems with input delay and saturation. During the process of the control scheme, neural network is employed to approximate the unknown nonlinear uncertainties and the appropriate barrier Lyapunov function is introduced to prevent violation of the constraint. In addition, for the issue of input saturation with time delay, a smooth non-affine approximate function and a novel auxiliary system are utilized, respectively. Moreover, adaptive neural tracking control is developed by combining the command filtering backstepping approach, which effectively avoids the explosion of differentiation and reduces the computation burden. The introduced filtering error compensating system brings a significant improvement for the system tracking performance. Finally, the simulation result is presented to verify the feasibility of the proposed strategy. [ABSTRACT FROM AUTHOR]

Piperine, derived from black pepper (Piper nigrum L.), is responsible for the pungent sensation. The diverse bioactivities of piperine underscores its promising potential as a functional food ingredient. This review presents a comprehensive overview of the research progress in extraction, synthesis, pungency transduction mechanism and bioactivities of piperine. Piperine can be extracted through various methods, such as traditional, modern, and innovative extraction techniques. Its synthesis mainly included both chemical and biosynthetic approaches. It exhibits a diverse range of bioactivities, including anticancer, anticonvulsant, antidepressant, anti-inflammatory, antioxidant, immunomodulatory, anti-obesity, neuroprotective, antidiabetic, hepatoprotective, and cardiovascular protective activities. Piperine can bind to TRPV1 receptor to elicit pungent sensation. Overall, the present review can provide a theoretical reference for advancing the potential application of piperine in the field of food science. [Display omitted] • Piperine can be effectively obtained by extraction and synthesis methods. • Piperine exhibits various bioactivities in vitro and in vivo. • The binding of piperine to TRPV1 receptor elicits a pungent sensation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tensile and fatigue properties of CM and PBF-LB samples are compared. • Integrated characterization approaches are employed to reveal fatigue mechanisms. • The importance of cellular structures on fatigue properties is highlighted. • The difference in fatigue properties between PBF-LB and CM samples is explained. The mechanical properties of ASTM F1684 (Invar 36) alloy manufactured via laser beam powder-bed-fusion (PBF-LB) technique are strongly influenced by the non-equilibrium solidification microstructure. Due to the complexity of printed microstructure, e.g. , the presence of melted pools, nano-precipitates, and high-density dislocations, it is very challenging to disentangle the specific mechanisms responsible for the fatigue properties. Here, a comparative investigation of the fatigue properties between PBF-LB and conventionally manufactured (CM) samples was conducted. Dedicated characterizations, including electron channeling contrast imaging (ECCI), and high-angular resolution EBSD (HR-EBSD), were performed. The mid-cycle (104–105 cycles) fatigue behaviors of both samples are comparable, while the fatigue resistance of PBF-LB sample becomes inferior at high-cycle range (≥ 106 cycles). This disparity can be ascribed to the competing effect between crack nucleation and propagation. PBF-LB samples are more susceptible to fatigue crack initiation due to the printed macro-defects. Whereas, the homogeneous plastic deformation and the grain fragmentation, both triggered by the ultrafine cellular structure, efficiently mitigate crack propagation rates. Based on these findings, the current understanding of the underlying mechanisms governing the fatigue performance of PBF-LB Invar 36 alloy is deepened, emphasizing the significant advantages of non-equilibrium solidification microstructure in retarding fatigue crack propagation. [ABSTRACT FROM AUTHOR]

Starch retrogradation is of great importance to the quality of starch-based food. This study investigated the effect of partial gelatinization (PG) synergizing with polyphenol (epicatechin, EC; epigallocatechin gallate, EGCG) on the multi-scale structure and short/long-term retrogradation of corn starch (CS). The PG synergizing with EC/EGCG substantially suppressed the short/long-term retrogradation properties of CS. These could be confirmed by the decreased storage modulus and viscosity, the relative crystallinity (1.54%, 3.56%), and the retrogradation degree (9.99%, 20.18%) of CS during storage for 1, 14 days after PG synergizing with EGCG and EC, respectively. This is because PG treatment promoted the hydrogen bond interaction between disordered starch molecules and EC/EGCG. These were proven by the larger aggregation, more and brighter fluorescents, and the reduced long/short-range order structures in CS after PG synergizing with EC/EGCG. This study is helpful for the development of foods with enhanced nutrition and low-retrogradation. [Display omitted] • PG (partial gelatinization) synergizing with polyphenol effectively delays retrogradation of corn starch. • The synergistic effects of epicatechin and epigallocatechin gallate with PG on starch retrogradation is different. • PG treatment promotes the hydrogen bond interaction between starch and polyphenol. • PG synergizing with polyphenol decreases the formation of crystalline structures. [ABSTRACT FROM AUTHOR]

The corrosion behavior of a well-polished Alloy 690 in deaerated supercritical water at 600 °C was examined. The study found that the weight gain follows a near-cubic rate law. A key observation was that the direct external oxidation and the rapid transition from internal to external oxidation within the initial 24-h exposure are responsible for its superior oxidation resistance. As exposure time increases, the transformation of Cr-rich spinel oxides and Ni-rich networks in the internal oxidation zone into Cr 2 O 3 leads to the expansion of the protective chromia layer, effectively slowing down the oxidation process. Conversely, the Cr 2 O 3 layer at the grain boundaries (GBs) was less effective at preventing oxidation, resulting in a significantly faster oxidation rate in these areas compared to the bulk grains. The extensive GB oxidation exhibits little consequential correlation with carbides. • The oxidation kinetics of Alloy 690's in deaerated supercritical water (SCW) at 600 °C were investigated. • The rapid transition to external oxidation and the expansion of compact chromia layer are responsible for the superior oxidation resistance. • The severe GB oxidation proceeds about six times faster than the bulk matrix due to its faster elemental diffusivity along the migrated GB. • GB carbides does not exhibit any consequential relationship with the depth of Diffusion-induced grain migration or the extent of GB oxidation. [ABSTRACT FROM AUTHOR]

The multi-condition operating characteristics of an organic Rankine cycle (ORC) are crucial to the development of the practical unit. This work developed a steady-state model of a small-scale ORC prototype built and tested in the lab. The influence of heat source/sink parameters, component design, and operation strategies are analyzed. It is found that the optimal output power and thermal efficiency correspond to the similar expander rotating speed but diverse working fluid mass flow rate. The higher mass flow rate is beneficial to the output power whereas deteriorates the thermal efficiency. Heat source temperature and flow rates mainly affect the unit output power while the ambient temperature and humidity influence both the output power and thermal efficiency. The condenser fouling resistance leads to a significant reduction of expander output power and system thermal efficiency. However, the effect of the evaporator fouling resistance could be neglected due to its sufficient redundant area. The long-term climate conditions and operating strategies profoundly impact the unit's off-design performance. The annual constant output power operation can be achieved by adjusting the working fluid mass flow rate. The thermal efficiency of the unit is damaged while pursuing the output power stability in winter and spring. • A small-scale ORC prototype using R245fa is built and tested. • A steady-state model of the ORC prototype is developed and validated. • The influence of heat source/sink parameters, component design is analyzed. • Multi-condition operating characteristics under two control strategies are compared. • Annual performance of the system applied for different scenarios is predicted. [ABSTRACT FROM AUTHOR]

As a self-centering element in a recoverable functional structure, shape memory alloys (SMAs) usually require a large diameter to provide sufficient bearing capacity, and pre-strain is applied to obtain good self-centering performance and initial stiffness. This study aims to explore the mechanical properties of large-diameter NiTi SMA cables and their potential applications in recoverable functional structures. Through the uniaxial tensile test of 11 SMA cables with 7 × 7 × 1.0 mm, the mechanical properties of SMA cables under different strain amplitudes, cyclic loading effects, loading rates, and different pre-strain modes were evaluated. The results indicate that the energy dissipation capacity of SMA cable increases with the increase of strain amplitude, but at the same time, it will reduce its self-centering capabilities. The equivalent viscous damping ratio decreases after the SMA cable enters the martensitic hardening stage. The residual strain of SMA cable depends on the combined effect of strain amplitude and number of cycles. The larger the strain amplitude and the number of cycles, the more significant the degradation of self-centering performance. After 20 times of constant amplitude loading and unloading, the mechanical properties of SMA cable are relatively stable. The reverse phase transformation stress of the pre-strained SMA cable gradually decreases with the increase of the tensile strain amplitude. The pre-strained SMA cable exhibits a stable restoring force strength in the sub-cycle, and the residual strain is zero. The test results support experimental data for applying large-diameter SMA cables in recoverable functional structures. • The equivalent viscous damping ratio decreases after the SMA cable enters the martensitic hardening stage. • The residual strain of an SMA cable is contingent upon the combined influence of strain amplitude and the number of cycles. • Faster loading raises reverse transformation stress, with little effect on forward transformation levels. • The reverse phase transformation stress in a pre-strained SMA cable decreases as the tensile strain amplitude increases. • In the sub-cycle, the pre-strained SMA cable maintains a stable restoring force strength, and the residual strain is zero. [ABSTRACT FROM AUTHOR]

Von Hippel−Lindau (VHL) syndrome is a rare disease that occurs in an autosomal-dominant genetic pattern. Due to the high genetic variability of VHL diseases, current studies have limited clinical value. Moreover, casual genetic variations in patients with VHL syndrome are still unclear. Here, we performed whole-exome sequencing of 25 individuals to identify reliable disease-related variations. Systemic computational analysis was performed for variant detection, and Sanger sequencing was used to validate detected mutations. Most of the known mutations in the VHL gene were observed in the studied population. In addition, a large fragment deletion in VHL exon 2 in the immediate family members of the last family was detected. This had not been reported earlier. Moreover, we identified 3 novel mutation sites in the MAP2K3 gene that may be involved in the occurrence and development of the VHL disease. These results demonstrated that the heterogeneous nature of VHL syndrome and novel mutational signatures may help to improve the diagnostic ability of VHL syndrome. [ABSTRACT FROM AUTHOR]

The exploration of preparing hierarchically porous carbons with adjustable pore structure from renewable biomass has attracted increasing attention by researchers. In this paper, the hierarchically porous carbon with excellent electrochemical properties is synthesized using renewable sodium alginate as a carbon source by in-situ pyrolysis of 'egg-box' structure with the addition of thiourea. The type/concentration of template resources and the thiourea additive have an important influence on the regulation of pore structure and the content of heteroatom here. More importantly, the doping of graphitic-N is conducive to enhancing the cycle stability of the electrode material. The PCNS–Zn sample has the most outstanding electrochemical performance with the high specific capacitance of 350 F g−1 at 1 A g−1 and the good rate capability of 82% capacitance retention at 50 A g−1. In addition, PCNS–Zn electrode shows a prominent cycle life with the capacitance retention rate of 90.4% at 5 A g−1 after 5000 cycles. From the perspective of sustainability, low cost and easy operation, this scheme has a broad development prospect for preparing porous carbon with controllable pore structure. • Porous carbons have been prepared by assembling of alginate and divalent cationic. • The template sources have an influence on the pore structure and nitrogen species. • Thiourea could regulate the size of template nano particles. • The doping of graphitic-N is conducive to enhance the cycle stability. [ABSTRACT FROM AUTHOR]

• In-situ observation of the dislocation-scaled and grain-scaled microstructures evolution in the additively manufactured 316L stainless steel. Revealing of emission of abundant stacking faults from cellular structures at the yielding stage, for the first time, in the bulk samples. • Quantification of the total dislocation density (∼1015 m−2), the geometrically necessary dislocation density (1.5–2 × 1014 m−2) and the misorientation angle (0.05–0.1°) of the cellular structures using high-resolution electron backscatter diffraction combined with electron channeling contrast imaging. • Identification of the intrinsic dislocation configurations of cellular structures as faulted dipoles, which significantly modulating the dislocation/twining behaviors of additively manufactured 316L sample. • The extremely fine slip band spacing rising high passing stress, playing a decisive role in the high macroscopic yield strength of additively manufactured 316L sample. • Instead of work hardening capability, the maintained ductility of additively manufactured 316L sample attributed to a complex interplay of several modulated plastic deformation mechanisms regulated by the hierarchical microstructure. The laser beam powder-bed-fusion (PBF-LB) technique offers the possibility to fabricate metallic materials with unparalleled mechanical properties. However, due to the complexity of nonequilibrium solidification structures, untangling the role of specific structural features in influencing mechanical properties through post-mortem analysis remains a significant challenge. Here, we tracked the complete evolution of deformation microstructures in PBF-LB 316L stainless steel (SS) and conventionally manufactured (CM) counterparts using in-situ electron channeling contrast imaging (ECCI) in conjunction with high-angular resolution electron backscatter diffraction (HR-EBSD). Our findings underscore the importance of the intrinsic dislocation configuration, i.e. , faulted dipole, in modulating the plastic deformation behaviors of the PBF-LB sample. The periodic arrangement of faulted dipoles triggers a widespread activation of stacking faults (SFs) with extremely fine spacing at the yielding stage, resulting in a high passing stress (∼433 MPa) that is responsible for the high yield strength. Meanwhile, such configuration facilitates uniform plastic deformation and mediates twinning propensity, thereby alleviating stress concentrations and enhancing ductility. Moreover, by correlating the mechanical response with microstructural evolution, we establish a modified model for multiple strengthening mechanisms in the PBF-LB sample. Additionally, we examine the effect of nonequilibrium solidification structures on the strain rate sensitivity of PBF-LB samples. Taking 316L SS as an exemplar, our results extend the current understanding of the structural origins responsible for the exceptional mechanical properties of metals manufactured by PBF-LB. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The recent research progress on extraction of food proteins by DES is reviewed. • DES can exhibit high extraction efficiency in the extraction of food proteins. • The structure and activity of extracted proteins can completely be retained by DES-based method. • DES with low viscosity, high selectivity and back-extraction efficiency is needed. The constantly improved quality of life leads to increasing demand for high-quality food proteins. Thus, the high-efficiency extraction methods of food proteins are highly needed. However, the traditional alkali-solution and acid-isolation method employs a large amount of corrosive acid/alkaline solution, which not only pollutes the environment, but also causes denaturation of proteins. Therefore, developing a novel green extraction method is of great significance. Deep eutectic solvents (DES), characterized by good biodegradability, sustainability and low toxicity, have become a green solvent in the past years. Extraction of food proteins by DES can overcome the shortcomings of corrosive solvents (e.g. NaOH, HCl and H 2 SO 4) used in traditional methods, making it a promising novel green extraction method. In this work, the information on DES was firstly recapped. Furthermore, the latest research progress on the extraction of food proteins by DES was emphatically reviewed. In addition, the challenges and future perspectives for DES-assisted extraction were discussed. Overall, the DES-based methods exhibit high extraction efficiency in extracting animal and plant proteins, amino acids, and enzymes, while the extracted proteins were non-denatured. However, DES-based protein extraction method still faces some challenges, such as high viscosity, poor extraction selectivity and inefficient back-extraction method. The present work can provide a theoretical reference for applying DES in the green extraction of food proteins. [ABSTRACT FROM AUTHOR]

The development of heavy oil reservoirs with active edge and bottom water is one of the most challenging problems in petroleum engineering. In response to the limited thermal recovery of these reservoirs, a multi-phase and multi-component numerical simulation model for thermal and chemical recovery is proposed. An edge-water assisted chemical flooding (EAC flooding) is proposed, which can improve oil displacement efficiency and sweep efficiency by rational utilization of edge-water energy when compounding multi-component chemical system. Then, a deep reinforcement learning algorithm is proposed to predict dynamic production parameters and determine the optimal working system to maximize the oil recovery according to the above mathematical model. The deep reinforcement learning (DRL) model can predict the dynamic production curves according to given states with optimal strategy. At the same time, the proposed model can determine the best conversion timing from cyclic steam stimulation to EAC flooding. Finally, the DRL model can automatically obtain the optimal working system, effectively improving the oil recovery while considering the economic benefits. Thus, the DRL model can solve traditional numerical simulation's time-consuming and labor-intensive challenges and accurately give the optimal working system for developing heavy oil reservoirs with edge water in the field. • A deep reinforcement learning-based model is developed to provide an optimal working system. •The DRL model can predict production performance with optimal strategy. •The model can predict the best conversion timing for different production stages. •The model can be used as a screening or decision-making tool for projects in the field. [ABSTRACT FROM AUTHOR]

• The 3D hierarchically porous carbon were synthesized via in-situ template and KOH activation from pectin. • The activation temperature and the addition of urea can adjust the content of heteroatoms and the pore structure. • The in-situ hard template can adjust the micropore/mesopores ratio. • The high specific surface area and its suitable micropore/mesopores ratio are helpful to promote charge storage and ion transfer. Pectin as a functional biopolymer has been successfully exploited to produce N/O co-doped 3D carbon architecture with hierarchical pores. A simple and novel in-situ template combining with KOH activation method is utilized to prepare porous carbon using calcium acetate as the template source and urea as a dopant. The in-situ CaCO 3 template, activation temperature and urea additive have a significant influence on the morphology, pore structure and performance of porous carbon. The high specific surface area of NHPC-700 (2928 m2 g −1) and its suitable micropore/mesopores ratio are helpful to promote specific capacitance and rate performance. The NHPC-700 possesses the high specific capacitance of 338 F g −1 at 1 A g −1 and the excellent capacitance retention of 83% from 1 A g −1 to 50 A g −1. Furthermore, the NHPC-700 symmetric supercapacitor shows an energy density of 22.4 Wh kg−1 at 880 W kg−1 in 1 M Na 2 SO 4. The efficient use of pectin to synthesize functionalized hierarchical porous carbon materials has a broad development prospect. Image, graphical abstract [ABSTRACT FROM AUTHOR]

[Display omitted] • A universal, low-cost technique for fabricating absorbing-coating-assisted laser-induced periodic surface structures (ACA-LIPSS) on various types of solids is developed via nanosecond laser irradiation of ink coating on a solid surface. • An analytical model based on the standing-wave laser field is proposed to elucidate the different effective refractive indexes of ink layers on different substrates. • The ACA-LIPSS technique with the erasable characteristic can be employed to color both handmade artworks and digital scanning patterns. Brilliant iridescent structural color can be realized by micro-/nanostructuring of solid surfaces, but the preparation processes are usually complex and expensive. In the article, a universal, low-cost technique for fabricating absorbing-coating-assisted laser-induced periodic surface structures (ACA-LIPSS) on various types of solids including polymers, dielectrics, semiconductors, and metals, is developed via nanosecond laser irradiation of the ink (Solvent Black 7) coating on a solid surface. Because ink layers on different solid surfaces can be similarly coated manually and removed chemically, the ACA-LIPSS technique with the erasable characteristic can be employed to color both handmade artworks and digital scanning patterns on various solids universally. Moreover, an analytical model based on the standing-wave laser field is proposed to elucidate the different effective refractive indexes of ink layers on different substrates, and thus obtain the corresponding theoretical periods of ACA-LIPSS, which are in good agreement with the experimental ones with error <10%. In short, as a versatile surface micro-/nanostructuring approach, ACA-LIPSS successfully prepared on a variety of solids with high material universality, good durability, and rewritability show great application potentials in artwork creation, encryption, anti-counterfeiting, and deformation sensor. [ABSTRACT FROM AUTHOR]

• We propose a method to evaluate the overall achievement of scientists. • We measure the achievement of a scientist by comparing him with other scholars active in the same period. • We assess the resulting ranking method using the American Physical Society citation data and four prestigious physics awards. • Our results show that the new method significantly outperforms other ranking methods in identifying the prize laureates. Evaluating scholars' achievements is an important problem in the science of science with applications in the evaluation of grant proposals and promotion applications. Since the number of scholars and the number of scholarly outputs grow exponentially with time, well-designed ranking metrics that have the potential to assist in these tasks are of prime importance. To rank scholars, it is important to put their achievements in perspective by comparing them with the achievements of other scholars active in the same period. We propose here a particular way of doing so: by computing the evaluated scholar's share on each year's citations which quantifies how the scholar fares in competition with the others. We assess the resulting ranking method using the American Physical Society citation data and four prestigious physics awards. Our results show that the new method significantly outperforms other ranking methods in identifying the prize laureates. [ABSTRACT FROM AUTHOR]

• The petal-like NiFeCo-S@NiFeCo-TH ultrathin nanosheets were in situ synthesized on NIF. • The Co2+ exchange reaction plays a vital role in fabricating the ultrathin nanosheets. • The NiFeCo-S@NiFeCo-TH displays rich active sites and short mass diffusion path. • The self-supporting NiFeCo-S@NiFeCo-TH nanosheets show a high energy density. Rationally designing self-supporting heterogeneous nanostructured electrode materials is an effective strategy to enhance electrochemical performance and mechanical strength for asymmetric supercapacitors. Herein, we report a facile synthesis of the self-supporting petal-like NiFeCo-S (Sulfides) @NiFeCo-TH (Ternary Hydroxides) heterogeneous ultrathin nanosheets on nickel iron foam (NIF) using an innovative electro-oxidation, sulfuration and controllable Co2+ exchange process. Petal-like NiFeCo-S@NiFeCo-TH ultrathin nanosheets with the thickness of only 1.8 nm consist of Ni 2 S 3 , FeS, CoNi 2 S 4 , FeCoS 2 and NiFeCo hydroxides nanocrystallines to provide rich interfaces. The unique nanostructured NiFeCo-S@NiFeCo-TH lamellar hybrid delivers the high areal capacity (mass capacity) of 973 µAh cm−2 (174 mAh g−1) at a current density of 10 mA cm−2 and excellent rate capability of 68.3% at a high current density of 100 mA cm−2. More importantly, the assembled NiFeCo-S@NiFeCo-TH/NIF//AC all-solid-state ASC device exhibits a high energy density of 56.3 Wh kg−1 at a power density of 543 W kg−1 and the outstanding cycling stability of 90.1% capacity retention after 4000 charge-discharge cycles. This synthesis strategy exhibits wide application prospect in fabrication of the self-supporting transition metal nanostructured electrodes for energy storage and conversion. [ABSTRACT FROM AUTHOR]

Bacteria involved with ecosystem N cycling in the rhizosphere of submerged macrophytes are abundant and diverse. Any declines of submerged macrophytes can have a great influence on the abundance and diversity of denitrifying bacteria and anammox bacteria. Natural decline, tardy decline, and sudden decline methods were applied to cultivated Potamogeton crispus. The abundance of anammox bacteria and nirS denitrifying bacteria in rhizosphere sediment were detected using real-time fluorescent quantitative PCR of 16S rRNA, and phylogenetic trees were constructed to analyze the diversities of these two microbes. The results indicated that the concentration of NH 4 + in pore water gradually increased with increasing distances from the roots, whereas, the concentration of NO 3 − showed a reverse trend. The abundance of anammox bacteria and nirS denitrifying bacteria in sediment of declined P. crispus populations decreased significantly over time. The abundance of these two microbes in the sudden decline group were significantly higher (P > 0.05) than the other decline treatment groups. Furthermore, the abundances of these two microbes were positively correlated, with RDA analyses finding the mole ratio of NH 4 +/NO 3 − being the most important positive factor affecting microbe abundance. Phylogenetic analysis indicated that the anammox bacteria Brocadia fuigida and Scalindua wagneri , and nirS denitrifying bacteria Herbaspirillum and Pseudomonas , were the dominant species in declined P. crispus sediment. We suggest the sudden decline of submerged macrophytes would increase the abundance of anammox bacteria and denitrifying bacteria in a relatively short time. • P. crispus decline significantly decreased the abundance of anammox bacteria and nirS. • Abundance of two microbes in sediment were significantly difference in each group. • Two microbe abundances were positively correlated in the sediment of the sudden decline group. • NH 4 +/NO 3 − was significantly positive related with the abundances of these two microbe types. [ABSTRACT FROM AUTHOR]