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The structure and function of microbial communities in aquaculture water bodies are important in the aquaculture ecosystem. To comprehensively and systematically evaluate the structure and functional composition of the microbial community in the water during Chinese mitten crab (Eriocheir sinensis) cultivation, the water quality indicators in the crab pond in Chongming District, Shanghai were monitored monthly from June to October 2022. The microbial species and functional structural characteristics in the water environment during the breeding period were analyzed based on metagenomics technology, and their relationships with environmental factors were discussed. The results showed that the major water quality indicators that exceeded the standard in the breeding pond were pH, permanganate index, total phosphorus, and total nitrogen. During the breeding period, the diversity of the microbial community in the water body from June to August and the richness of the microbial community from July to August were high, and the dominant microbial phyla in the water body were mainly Proteobacteria, Bacteroidetes, Actinobacteria, Verrucomicrobia, Cyanobacteria, and Uroviricota. At the genus level, the top 10 dominant genera regarding abundance were significantly different among multiple groups. For example, the abundances of Microcystis bacteria in July and unclassified_o_Caudovirales viruses in August–October were significantly higher than those in other months. The primary function of microorganisms is metabolism, including energy metabolism, global and overview maps, and amino acid metabolism. Notable differences are present in the functional composition of different months; particularly, the abundance of metabolic pathways in June–July was significantly higher than that in August–October, and the dominant bacteria (Proteobacteria, Actinobacteria, and Bacteroidetes) were major contributors to the aforementioned functions. The influence trends of environmental factors on the structure and functional composition of microbial communities were consistent. Chlorophyll a and pH had the most significant impact on the structure and functional composition of microbial communities, whereas dissolved oxygen and total phosphorus had a slightly weaker impact. The pathogenic bacteria with a relatively large abundance in aquaculture water bodies are Salmonella enterica, Edwardsiella ictaluri, and Staphylococcus aureus. The research results provide basic data for the study of microbial community structure and functional composition in water bodies of Chinese mitten crab breeding ponds and can provide a theoretical basis for aquaculture water quality control and ecosystem construction.

The sensory quality and metabolite profiles of the fresh and dried buds and leaves of Lycium from 26 cultivars (lines) were analyzed by sensory evaluation and metabolomics combined with multivariate statistical analysis. The results of sensory evaluation showed that the dried buds and leaves of Lycium had a mellow, fresh and sweet taste, and by liquid chromatography-mass spectrometry (LC-MS), 879 metabolites were identified in Lycium buds and leaves, including amino acids and their derivatives, flavonoids, phenolic acids, saccharides, nucleotides and their derivatives, lignans and coumarins, alkaloids, terpenoids, organic acids, and lipids. Using partial least square discriminant analysis (PLS-DA) model and one-way analysis of variance (ANOVA), 211 differential metabolites were selected, which were mainly enriched in the linoleic acid metabolism, flavonoid biosynthesis, flavonoids and flavanols biosynthesis, phenylpropanol biosynthesis, and galactose metabolism pathways. In addition, it was found that amino acids and their derivatives, flavonoids, sugars, and lipids were important components to discriminate the metabolites of different cultivars (lines). Partial least squares regression (PLSR) analysis showed that 26 metabolites including epicatechin, isoquercitrin, and rutin collectively affected the taste of Lycium tea such as mellow, thick, fresh, sweet and bitter. The results of sensory evaluation and PLSR analysis showed that seven cultivars (lines) of Lycium including ‘Ningqicai No. 1’, ‘Ningqi No. 9’, Z90, Z68, Q3, Q6-13, and Z48 had better sensory quality and rich flavor substances.

With the proposal of the "dual carbon”goals，using hydrogen as zero-carbon alternative fuel has become an important trend of the aviation industry in the future. In recent years，the hydrogen-fueled aero-engines have garnered significant attention. Superalloys are the most widely used materials in the hot section components of gas turbine engines. The purpose of this review is to provide reference for the research and development of superalloys for hydrogen-fueled aero-engines future use by understanding the effects of hydrogen-related environment on superalloys currently across various fields. Internal/external hydrogen environments，hydrogen permeation（charging）methods，measurement of hydrogen concentration/distribution or stable existence temperature，the influence of hydrogen on tensile strength，the impact of hydrogen on creep/stress rupture and fatigue properties，and the fracture mechanism of hydrogen embrittlement are described. The degradation factors of mechanical properties of superalloys with different composition，manufacturing process，original microstructure，alloying degree and different application fields under hydrogen-related environment are summarized. In general, mechanical properties tests in the external hydrogen environment exhibit more significant hydrogen-assisted mechanical degradations than that in internal hydrogen environments. Superalloys with higher alloying degree exhibit more pronounced hydrogen embrittlement，while the tendency of properties decrease（creep/rupture，fatigue and tensile）in hydrogen at elevated temperature is much less than that at room temperature. The prospects for the mechanical performance evaluation of current superalloys in hydrogen-related environments for hydrogen-fueled gas turbine and the development of new alloys suitable for hydrogen environments are provided. Hydrogen-fueled gas turbine aero-engines may encounter cryogenic temperature hydrogen environment for liquid hydrogen storage，hydrogen environment for cooling，high-temperature/high-pressure hydrogen environment for gas compression，and the impact of combustion products–water vapor（humid）at elevated temperature. Diffusion or permeation of hydrogen in superalloys，the embrittlement and corrosion of alloys in high-pressure hydrogen environments，oxidation and corrosion behavior in high-temperature humid environments，as well as the degradation and protection mechanism for alloys and coatings in the aforementioned multiple coupling environments shall be concerned. It is necessary to establish hydrogen combustion environment experimental facility that closely simulates service conditions to conduct research on the impact of hydrogen-related environment on superalloys and their components. It is also essential to establish a mechanical performance database and standards for currently used key materials in hot section components such as turbine blades and disks for hydrogen related environments，and properly develop new high-temperature structural materials suitable for hydrogen combustion conditions，which will provide support for the application of hydrogen fueled gas turbine aero-engines.

ObjectiveIn order to study the distribution of ship ice pressure during the interaction between an icebreaker and pack ice, a numerical simulation analysis is carried out for polar ships in pack ice channels. MethodThe discrete element method (DEM) is used to model the ship and pack ice. It is assumed that the pack ice is composed of an ideal two-dimensional disc, and the effects of the ocean current on the buoyancy, drag and additional mass of the pack ice are taken into account. The numerical model is validated by comparison with the experimental results of an MT Uikku model, and the effects of different speeds and ice conditions on the ship ice pressure in the pack ice area are analyzed. ResultsThe results show that the ice load is mainly concentrated on the bow of the ship when it moves in the pack ice channel. The ice pressure in the bow area increases with the increase in ice thickness, speed and the density of pack ice, among which ice thickness is the most important factor affecting the amplitude of the ice pressure. The ice pressure in the pack ice area has the greatest influence on the ice pressure in the bow area, and the ice pressure in the bow transition area has a significant effect. ConclusionThe numerical analysis method can provide certain references for the safe navigation and structural design of polar ships.

Objective To observe the effect of thunder-fire moxibustion on joint function recovery after surgery for fractures around the knee. Methods Totally 50 patients were divided into 2 groups (control group and observation group) by random number method. The control group was treated with routine treatment and nursing interventions after surgery, and the observation group was treated with thunder-fire moxibustion on the basis of routine treatment. The clinical effect of the two groups was compared. Results A total of 48 patients were followed up with complete results, including 24 cases in the control group and 24 cases in the observation group. The upper and lower diameters of the affected limb in the observation group were smaller than those in the control group after 3 and 7 days of treatment, with a significant difference(P＜0. 05). The Visual Analogue Scale (VAS) score of the observation group was significantly lower than that of the control group after 3, 5 and 7 days of treatment, with a significant difference(P＜0. 05). After 1, 3 and 5 weeks of treatment, the Hospital for Special Surgery (HSS) knee scores in two groups were higher than those before treatment (P＜0. 05), and the HSS knee score in the observation group was higher than that in the control group after 3 and 5 weeks of treatment (P＜0. 05). The range motion of the knee in the observation group was better than that of the control group after 7 days of treatment, with a significant difference(P＜0. 05). Conclusion Postoperative nursing combined with thunder-fire moxibustion can effectively reduce the swelling and pain of the affected limb, improve the range of motion and function of the knee joint, and improve the clinical treatment effect. (目的 观察雷火灸联合护理干预促进膝关节周围骨折术后关节功能恢复的效果。方法 采用随机数字表法将50例患者分为对照组和观察组。对照组给予常规治疗和护理, 观察组在对照组基础上增加雷火灸治疗。比较两组干预效果。结果 随访共得到48例患者完整结果, 对照组及观察组各24例。治疗3 d、7 d后, 观察组患者患侧上、下周径均小于对照组, 差异有统计学意义(P＜0. 05)。治疗3 d、7 d后, 观察组患者患侧VAS评分低于对照组, 差异有统计学意义(P＜0. 05)。治疗1周、3周、5周后, 观察组患者患侧膝HSS评分均较治疗前提高(P＜0. 05); 治疗3周、 5周后, 观察组患者患侧膝HSS评分高于对照组(P＜0. 05)。治疗7 d后, 观察组患者患侧膝关节活动度大于对照组, 差异有统计学意义(P＜0. 05)。结论 膝关节周围骨折术后护理配合实施雷火灸治疗, 能有效减轻患肢肿胀、疼痛, 促进康复, 改善膝关节活动度及功能, 有利于提高临床治疗效果。)

ObjectiveWhen using the circumference crack method to calculate the ice load, the size of the circumference crack is usually determined by an empirical formula, but this can introduce many uncertainties to the selection of input parameters.MethodsTo accurately determine the size of circumference cracks, we propose a method of recognizing ice circumference crack size based on YOLACT, which can identify ice in images taken with ships. We then detect the edge of the mask and obtain the shape of the ice cracks, and the ice breaking radius and angle can be estimated by fitting the cracks.Results The results show that the accuracy of the ice breaking radius and angle estimated by the proposed method can reach up to 96.12% and 96.58% respectively.ConclusionThis method can accurately determine the size of circumference cracks and assist in the initial design of marine structures in cold regions.

ObjectiveTo investigate the characteristics of serum perfluoroalkyl substances （PFASs） exposure and potential influencing factors among community residents in Songjiang District， Shanghai.MethodsIn August 2021， residents who underwent routine health checkups in a community in Songjiang District， Shanghai were recruited as study subjects. The inclusion criteria were adult residents who had lived in the area for more than 3 years， had no occupational exposure history， no underlying diseases， were not pregnant， and were able to complete the questionnaire independently and sign the informed consent form. A questionnaire survey was conducted and venous blood samples were collected. The concentrations of 15 PFASs in serum were determined using ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry （UPLC-MS/MS）. Ordered multi-class logistic regression， interquartile range （IQR）， and odds ratio （OR） were used to explore the influencing factors and risk magnitude of serum PFASs concentrations.ResultsOf the 15 PFASs， 14 were detected， and the detection rates of 7 PFASs were higher than 50%. The highest detected concentrations among the PFASs were PFOS （perfluorooctane sulfonate）， PFOA （perfluorooctanoic acid）， and PFHxS （perfluorohexane sulfonate）， with median concentrations of 48.61 μg∙L-1， 37.29 μg∙L-1， and 36.51 μg∙L-1， respectively. The strongest correlation was between PFDA and PFUnDA （r=0.93， P

In order to use the dock for archaeological work in “Yangtze River Estuary II” ancient shipwreck salvage, the function of the old and disabled dock gate that has been abandoned for many years are restored. In order to resume service, the failure dock gate is tested, and the relevant removal, maintenance, and reinforcement of the dock gate are conducted based on the test results. After repair, the failed dock gate is lifted and opened successfully. After the ancient ship entered the shipyard, the gate closes smoothly, providing a good working environment for archaeological work. The recovery work of the failure dock gate is the first of its kind in the domestic shipbuilding industry. The full life cycle of special equipment such as dock gate is further understood.

ObjectivesThis paper aims to analyze the influence of polar low temperature environment and ballast water capacity on the dynamic change process of the temperature field in polar ship's ballast tank. MethodsThe volume of fluid (VOF) model was used to simulate the two phases of gas and liquid, and the standard k-ε turbulence model was used to simulate the fluid movement. The numerical analysis model of heat transfer in the ballast tank of polar ships was established to analyze the dynamic change process of the temperature field of the ballast tank at low temperature, and reveal the influence mechanism of multiple ambient temperatures and multiple loading heights on the temperature field of the ballast tank. ResultsWith the continuous occurrence of heat transfer, the temperature in the area above the waterline of the side ballast tank decreases rapidly, and the cooling area extends laterally to the cabin and downward along the bulkhead respectively. When there is more ballast water, the temperature field in the cabin is relatively stable due to the large heat capacity of water, but the air heat capacity is low and the temperature field changes greatly, which is prone to cyclones and further affects the temperature field distribution in the calculation domain. Under the condition of the same ballast water capacity, the lower the external ambient temperature, the greater the difference between internal and external temperatures, the more intense the heat exchange, and the faster the temperature of the ballast tank changes. ConclusionsThe VOF two-phase flow model and the standard k-ε turbulence model can better reveal the temporal and spatial evolution characteristics of the temperature field in the ballast tank in polar low temperature environment, and analyze the influence of internal and external thermal boundary conditions on the change of the temperature field in the ballast tank, which can provide necessary technical reference for the cold/freeze protection of polar ships' ballast tanks.

The rapid growth of the nuclear industry poses a great challenge for radioactive waste treatment. Volatile radioactive isotopes generated from uranium fission, especially gaseous iodine, attracted great attention due to their environment and health hazards. The widespread species of radioactive iodine are gaseous elemental iodine (I2) and methyl iodide (CH3I). It is difficult to trap the methyl iodide in high humid condition. Activated carbon and derivative materials are widely used as adsorbents to remove volatile iodine. Triethylenediamine (TEDA) is proposed as impregnation via isotope exchange mechanism. In this study, activated carbon fiber (ACF) with high surface area, heat resistant and chemically stable was used as substrate, TEDA-modified viscose-based activated carbon fiber was prepared by hydrothermal reaction. For fiber hydrothermal modified with 5% (mass fraction) TEDA, the surface area and pore volume decrease about 20%. Compared with conventional impregnation, more TEDA impregnation enters into the microporous structure of activated carbon fibers under hydrothermal environment. The gaseous iodine adsorption properties of modified activated carbon fiber were investigated. Static adsorption experiments of elemental iodine and methyl iodide were performed. The adsorption capacity of elemental iodine and methyl iodide increases by 36% and 50% respectively. Methyl iodide adsorption capacity of hydrothermal modified-ACF is 400 mg/g. The dynamic adsorption experiments show that the adsorption performance of modified activated carbon fiber for methyl iodine decreases with the increase of temperature and humidity. The adsorption performance of activated carbon fiber for methyl iodine is greatly affected by environmental humidity. Breakthrough experiment with 5 ppm of gaseous methyl iodide was conducted under high humid conditions (30 ℃, RH 95%), the feed gas flow rate was fixed at 15 L/min for 12 h. Breakthrough curve indicates that hydrothermal modified-ACF has good adsorption performance with respect to methyl iodide. The radioactive CH3131I adsorption experiments under severe conditions were carried out. The removal efficiency of hydrothermal modified-ACF increases from 29.11% to 94.85%. The affinity of methyl iodide is improved by TEDA-modified. The hydrothermal modified-ACF exhibits the high adsorption efficiency of gaseous iodine.

Natural pyrethrin is a green botanical insecticide that extracted from the aboveground tissues of pyrethrum (Tanacetum cinerariifolium). Aldehyde dehydrogenase (TcALDH) and GDSL lipase (TcGLIP) are key rate-limiting enzymes involved in pyrethrin biosynthesis pathway in pyrethrum. The promoters of TcALDH and TcGLIP genes were cloned from the genomic DNA of pyrethrum clone ‘W99’ in order to investigate the regulatory mechanism of these genes. The regulatory elements, activity, hormone specificity and tissue inducibility of the two promoters were analyzed through bioinformatics analysis, histochemical staining (GUS staining), luciferase reporting, and exogenous hormone treatment. The results were as follows: (1) Using pyrethrum genomic DNA as a template, specific primers were used to clone the pTcALDH and pTcGLIP fragments. The sequence lengths of pTcALDH and pTcGLIP were 2 848 and 1 343 bp, respectively, and the promoter analysis software the PlantCARE predicted that they both contained multiple cis-elements related to stress response and hormone signals. (2) The plant expression vectors fused by pTcALDH and pTcGLIP and luciferase report gene were constructed, and were transformed into tobacco (Nicotiana benthamiana) to analyse hormone inducibility by observing the fluorescence imaging in tobacco leaves. The results demonstrated that the pTcALDH displayed typical hormone inducibility of methyl jasmonate (MeJA) and abscisic acid (ABA), whereas the pTcGLIP showed no response. (3) The tissue culture seedlings of pyrethrum ‘W99’ were treated with MeJA and ABA, the expression of TcALDH was up-regulated by ABA within 12 h, and first increased and then decreased under MeJA treatment; the expression of TcGLIP was down-regulated by ABA and MeJA. (4) We constructed the expression vectors of pTcALDH and pTcGLIP fused with GUS reporters and transformed them into tobacco, then the transient transformation of tobacco drived the expression of GUS gene and showed initiating activity. It was found that the pTcALDH expressed in the glands, glandular hair heads and mesophyll of the leaves, while the pTcGLIP was only expressed in the parenchyma cell. These results indicated that the pTcALDH and pTcGLIP were tissue-specific promoters, and the pTcALDH appeared MeJA-inducible and ABA-inducible characteristics. This study provides a new insight into the regulatory mechanism of TcALDH and TcGLIP genes involved in pyrethrin synthesis.

Green sweat peppers are rich in nutrients and diverse in shape and color. Apart from being eaten as a vegetable, it is widely used as seasoning and side dishes. Due to respiration and infection by harmful microorganisms, postharvest green peppers are prone to water loss, wilting and even rot. Appropriate preservation technology can maximize the preservation of nutrients and extend the storage period of green peppers. This paper introduces the techniques used for postharvest preservation of green sweet peppers: physical preservation methods such as refrigeration and packaging, biological preservatives such as microbial, plant and animal extracts, and chemical preservatives such as calcium agents and 1-methylcyclopropene (1-MCP), and compares the advantages and disadvantages of these preservation techniques. It elaborates the effect of chitosan or konjac glucomannan-based composite coatings on preserving the quality of green sweet peppers. Our intention is to provide a reference and guidance for the storage and preservation of postharvest green peppers.

An analysis method for simultaneous determination of 46 kinds of fungicides and insecticides residues in tomatoes by QuEChERS method combined with gas chromatography-mass spectrometry was established. The samples were extracted with acetonitrile, then purified up with PSA, C18 and anhydrous MgSO4, separated by a HP-5MS chromatographic column, analyzed using multiple reflection monitoring (MRM) mode, and quantified by matrix-matched external standard method. The result showed that, the 46 kinds of pesticides showed good linearity when they were in 0.005～0.500 μg/mL (R2>0.999). The limits of detection of the 46 kinds of pesticides were in 0.07～2.63 μg/kg, and the limits of quantitation were in 0.21～8.39 μg/kg. The average recoveries were 70.40%～115.08% with the relative standard deviations of 0.22%～4.89% at the spiked levels of 0.0025, 0.025 and 0.25 mg/kg. Residues of chlorpyrifos and azoxystrobin were detected in 9 of the 50 batches of tomato samples, with the content ranging from 0.0043～0.0365 mg/kg, which did not exceed the limit value specified in GB 2763-2021. The method was rapid, simple, sensitive and accurate, which could meet the detection of multiple pesticide residues in tomato.

Objectives This study aims to investigate the dynamic coupling effect of "hull-fender-dock" during ship berthing.MethodsUsing the nonlinear finite element method, a port side and fender structure finite element model is established to simulate the dynamic evolution of speed, stress and energy during ship berthing. ResultsThe results show that when the fender makes contact with the dock, the ship's speed decreases to zero and the dynamic deformation and interaction force of the fender structure are at their maximum. When the ship is berthing, the fender shows strong energy absorption capacity, accounting for about 70% of the initial total kinetic energy of the ship, and the hull structure is well protected.ConclusionsFurther analysis indicates that, with the improvement of the initial berthing speed, port protection efficiency shows a decreasing trend. The ultimate berthing speed of the target ship of this study is 2.5 kn, and the recommended safe berthing speed is 2 kn. The results of this study can be used as a reference for ship berthing speed limits and hull structure energy absorption design.

With the integration of information technology and traditional industries,it has become a trend to use computer-controlled machines instead of humans to perform repetitive,boring and even dangerous tasks.In order to effectively interact with computers in natural language,human-computer interaction and dialogue systems based on multi-turn dialogue technology have become a research hotspot in the field of artificial intelligence and natural language processing.In the grid control system,the dispatcher needs to do a large number of query operations manually.To reduce the complexity of existing dispatching system and improve the speed of emergency handling of dispatchers,multi-turn dialogue technology can be applied to realize intelligent voice query of power grid data.This paper first describes the basic architecture of the task-oriented multi-turn dialogue system,including functions and related algorithms of its three modules:natural language understanding,dialogue management,and natural language generation.Next,in order to meet the demand of power grid companies for specific scenarios such as intelligent data queries,this paper designs and implements a multi-module task-oriented multi-turn dialogue system which consists of natural language understanding module,dialogue management module,natural language generation module and knowledge base as core mo-dules.The grid dispatcher can ask the system questions and get answers in the form of natural language.This process does not require keyboard or mouse operations,which greatly improves the rapidity and convenience of the grid information query.

Corundum-based (Al2O3) refractory materials prepared by powder metallurgy superalloy powder were heat treated at 950-1350 ℃ for 60 min in order to study the effect of temperature on the microstructure and particle shedding of corundum-based refractory materials. The phase structure of the refractory materials before and after heat treatment was analyzed by XRD. Scanning electron microscopy (SEM) with energy dispersive spectrum (EDS) was used to characterize the microstructure and phase composition of the refractory samples. In addition, the adhesion experiment was used to evaluate the particle shedding of the refractory materials after heat treatment at different temperatures, and explore the mechanism of pre-heating treatment reducing the possibility of particle shedding. Thermal shock test was used to evaluate the thermal shock resistance of refractory materials after heat treatment at different temperatures. The apparent porosity and bulk density were measured. The results show that with the increase of preheating temperature, the composition of calcium aluminate cement binder in refractories is gradually changed from CaAl2O4 (CA) to CaAl4O7 (CA2), and the fine ceramic particles in refractories are sintered together until the interconnected network structure is formed. With the increase of preheating temperature, the fine refractory particles in the refractory are gradually wet and spread on the large particles as aggregated and connected to form a network structure, and finally the large particles are coated. The particle adhesion of refractory gradually increases with the increase of heating temperature. The heat treatment has minor effect on the apparent porosity, bulk density and heat shock resistance of the refractory materials. However, with the increase of heating temperature, the local peeling degree of the refractory surface and mass loss rate in the thermal shock test are significantly improved. The particle shedding is obviously reduced whereas preheating for 60 min at 1150-1350 ℃, and the relative suitable preheating temperature is in the range of 1250-1350 ℃.

In recent years, many accidents occurred in the operation of pipe corridors at home and abroad. Especially with the entrance of power cables, gas and thermal pipelines, the risk factors of the pipe corridors were greatly increased. Pipeline damage and operators suffered injuries and deaths caused by electromagnetic interference of the pipeline in the corridor were the most important safety hazards for the safe operation of urban underground comprehensive corridors. In order to find out the influencing factors and laws of electromagnetic interference of high voltage transmission lines in the pipe corridor, and to provide technical support for the construction of corridors, the professional analysis software CDEGS was used to simulate the influence of the high voltage transmission lines in the corridor on the electromagnetic interference of the pipeline in the corridor. Results showed that the induced voltage and induced current on the pipeline increased with the increase of high voltage line voltage and soil resistivity, and firstly decreased rapidly and then slowly decreased with the increase of the distance between the pipeline and the high voltage line. The pipeline specifications had little effect on the induced voltage and induced current. As the resistivity of anti-corrosion layer increased, the induced voltage first increased and then tended to be stable, whereas the induced current decreased first and then tended to be stable.

For evaluating the corrosive performance of the soil in Wuhan, the composition of typical soil in Wuhan, Hubei Province was sampled and analyzed.The corrosion behavior of Q235 steel in Wuhan soil was studied by using actual soil buried test and accelerated corrosion test with controlling temperature and humidity and applying super depth of field microscope, focused ion beam scanning electron microscope(FIB-SEM)and electrochemical workstation.Experimental results showed that the soil environment in Wuhan was of “light” corrosion grade, and the Q235 steel had changed from non-uniform corrosion to general corrosion, and its surface showed pitting corrosion and spalling.In addition, the degree of corrosion increased with the extension of time, and its corrosion rate decreased and stabilized with the extension of time.With the progress of corrosion, the self-corrosion potential of Q235 steel increased, and the self-corrosion current density decreased.In summary, Q235 steel had acceptable corrosion resistance in Wuhan soil environment, which was suitable for large-scale use as structural materials.

The purpose of this work was to reveal the effect of phosphating pre-treatment on the protective performance of water-based epoxy varnish coating on surface of aluminum alloy(AA).A phosphating film was firstly prepared on the surface of 2024 aluminum alloy by chemical conversion method for phosphating pre-treatment, and then the surface of aluminum alloy without and after phosphating pre-treatment was coated with water-based epoxy varnish.After the varnish was completely cured into a coating, the protective effect of water-based epoxy coating on aluminum alloy without and after phosphating pre-treatment was evaluated by electrochemical impedance spectroscopy(EIS).Finally, the effect of phosphating pre-treatment on the protective performance of water-based epoxy varnish coating and its mechanism were revealed.Results showed that the phosphating coating on surface of aluminum alloy had a uniform and dense columnar crystal structure, which was mainly composed of Zn3(PO4)2·4H2O.In 3.5%(mass fraction)NaCl solution, both the protective layer resistance(Rc)and the impedance module at low frequency(|Z|0.01)of the epoxy/AA(E/A)system and the epoxy/phosphating coating/AA(E/P/A)system decreased gradually with the extension of immersion time; however, both Rc and|Z|0.01 of the E/P/A system were always greater than those of the E/A system.On the other hand, due to the phosphating pre-treatment, the average adhesive force(Fa)of water-based epoxy coating on the surface of AA increased from 10.47 MPa to 15.58 MPa.Compared with the direct coating of water-based epoxy varnish without phosphating pretreatment on the surface of AA, the coating with phosphating pre-treatment before water-based epoxy varnish treatment changed the whole protective layer on the surface of AA from a single epoxy layer to a composite epoxy layer/phosphating coating, resulting in a significant increase in Rc and|Z|0.01.More importantly, the existence of phosphating film improved the adhesion of water-based epoxy coating on the surface of AA, and even fundamentally changed the fracture form of the whole protective layer.The combined effects of the above two aspects improved the protective effect of water-based epoxy varnish coating on AA substrate.Also, the mechanism of phosphating pre-treatment on improving the protective performance of water-based epoxy varnish coating was revealed.

In order to study the volatile composition of onion, the volatile flavoring substances of the onion were extracted by headspace solid phase microextraction and determined by gas chromatography-mass spectrometry. The effects of extraction fiber head, extraction temperature, extraction time and desorption time on the total peak area and the number of effective compounds were investigated. The optimum extraction conditions were determined as follows: Extraction fiber 50/30 μm DVB/CAR/PDMS, extraction temperature 60 ℃, extraction time 60 min and desorption time 5 min. Under the optimum experimental conditions, the volatile compounds of onion with three different colors were analyzed and identified. The results showed that a total of 61 kinds of volatile flavor compounds were identified. A total of 37, 40 and 49 volatile flavor compounds were detected in the white, red, and yellow onions, respectively, and the peak area content of these volatile flavor compounds accounted for 70.29%, 81.92% and 79.03% of the total volatile components, respectively. In the 61 volatile flavor compounds, 27 were sulfur compounds, 13 were aldehydes, 13 were alcohols, 4 were ketones and 4 were others. There were 22 kinds of volatile components in the three color onions, of which sulfur-containing compounds account for a relatively large proportion, especially the relative content of diisopropyl disulfide and (E)-1-propenyl-2-propenyl disulfide. The sum of the volatile components of the three color onions accounted for more than 20%, which contributed a lot to the formation of the characteristic flavor of onions. The relative content of sulfur compounds in red and yellow onions was much higher than that of white onions. The relative content of 2-methyl-2-pentenoaldehyde in red onions was higher than that of white and yellow onions.

With the rapid progress of natural language processing techniques and the massive accessible conversational data on Internet,non-tasked oriented dialogue systems,also referred to as Chatbots,have achieved great success,and drawn attention from both academia and industry.Currently,there are two lines in chatbots research,retrieval-based chatbots and generation-based chatbots.Due to the fluent responses and low latency,retrieval-based chatbots is a common method in practice.This paperfirst briefly introduces the research background, basic structure and component modules of retrieval-based chatbots,and then illustrates the constraints of the response selection module and related data set in details.Subsequently,we summarize recent popular techniques for response selection problem,including:statistic method,representation-based neural network method,interaction-based neural network method,and pre-training-based method.Finally,we pose the challenges of chatbots and outline promising directions as future work.

Objective To study the neuroprotective effect of levetiracetam (LEV) with hypoxia ischemia brain-damage (HIBD) model of neonatal rats. Methods The rats were randomly divided into three groups: model group, LEV low, medium and high concentration groups [gavage with 10, 30, 50 mg/(kg·d) LEV], with 10 rats in each, and another 10 rats in sham operation group. Twenty four hours after the last administration, HE staining was used to observe the pathological changes of rat brain, TUNEL method was used to detect the apoptosis of neurons, the expression of inflammatory factors interleukin-6 (IL-6), tumor necrosis factor α(TNF-α), and oxidative stress factors malondialdehyde(MDA), the content and activity of superoxide dismutas (SOD) in serum were detected by ELISA, and the protein expression of caspase-3, B-cell lymphoma-2(Bcl-2), nuclear factor erythroid 2-related factor 2(Nrf2), heme oxygenase(HO-1) in rat brain tissue were detected by Western blot. Results Compared with the sham operation group, the morphology of brain tissue cell in the model group were disordered, showed diffuse distribution, increased vacuolation and inflammatory infiltration, the apoptosis rate of neurons, the expression of IL-6, TNF-α, MDA in serum and caspase-3 in brain tissue were significantly higher(P＜0.05), and the expression of SOD in serum, Bcl-2, Nrf2 and HO-1 in brain tissue were significantly lower(P＜0.05); Compared with the model group, the above changes of LEV in low, medium and high concentration groups were significantly reduced(P＜0.05). Conclusions LEV can alleviate inflammatory reaction and oxidative stress, and play a neuroprotective role in HIBD newborn rats.

Based on the daily precipitation data in Hunan Province from 1986 to 2015, reanalysis data of NCEP and NCAR in the same period, the prediction index of heavy precipitation in extended period of flood season in Hunan Province is established by analyzing the characteristics of heavy precipitation in flood season in strong low frequency oscillation year and the influence of low frequency circulation flow field evolution on heavy precipitation. The results are as follows. (1) 33% of the heavy rainfall in the flood season occurs in the years with significant 30-60 d low-frequency oscillation, and most of them are in the peak stage of low-frequency precipitation. (2) It is found that in the active phase, the South Asia high is strong to the East and the subtropical high is strong to the West. This circulation configuration leads to the divergence of the high-level circulation and the convergence of the bottom circulation in most areas of South China, which is conducive to the generation of precipitation. In the phase of interruption, the South Asia high is in the east-west zonal distribution, and its location is to the west and intensity is weak. The subtropical high is to the east and weak, which makes the southwest air flow of water vapor to Hunan area weaken and enter the period of precipitation interruption. (3) Based on the characteristics of different phases of low-frequency divergence field, two key areas related to low-frequency precipitation are selected to establish the extended period forecast index, which can achieve an accuracy of 73% for the return of heavy precipitation in the significant years of low-frequency precipitation. (4) The SSTA of Kuroshio in early April can be used as a prediction index of strong and low frequency oscillation years in Hunan Province.

Glioma is the most common primary tumor of central nervous system (CNS), about 50% of which is extremely malignant glioblastoma (GBM). GBM is the most common primary malignant brain tumors in adults. Surgery, radiotherapy and chemotherapy (most with temozolomide) are regarded as the conventional treatments, but they failed to significantly prolong the survival of GBM patients. The standard treatment of GBM lacks of specificity, and tumor cells are resistant to radiotherapy or alkylating agents, thus recurrence of GBM is inevitably and the overall prognosis is quite poor. Currently, tumor immunotherapy is emerging and booming, which provides more treating options for GBM. This study, hence, reviews the current status of immunotherapy among the comprehensive treatments of glioma, at the same time indicates the potential targets of immunotherapy, further to update treatment strategies and explain the potential for the resistance of immunotherapy. DOI：10.3969/j.issn.1672⁃6731.2019.11.003

The large-sized (?300 mm) nickel based superalloy GH738 billet was fabricated by spray forming followed by hot isostatic press (HIP) and hot extrusion (HEX) within varied deformation temperatures. The micro-defect, carbonitride distribution, γ/γ′ evolution during the hot processes were investigated by the relevant approaches including XRD, SEM, TEM, EBSD and phase analysis technique respectively. The results show that the porosities in γ matrix of spray deposited billet are welded up to closure after HIP process. The difference of characteristic microstructure after dynamic recrystallization obtained after the hot extrusion is mainly based on the varied deformation conditions including temperature and strain-stress state. The grain-boundary-distributed carbonitrides in HIPed billiet are transformed into extrusion-direction-along distribution after hot extrusion. The effects of temperature field delivered and cooling condition on elements constitution, mass fraction, morphology, size and distribution of γ′ in GH738 are validated during different hot processes as well.

In order to solve the problem of hidden key leakage in traditional high-level message authentication and passive eavesdropping in physical layer message authentication,a message encryption and authentication mechanism based on the characteristics of wireless physical layer was proposed.By extracting the characteristics of the wireless channel,the physical layer key was generated and the seed key was generated by combining the identity key.The key stream generator then generated the key stream to decrypt the message according to the extracted seed,protects the privacy of the transmitted data,and the final receiver authenticated the authenticity and integrity of the received message through the CRC verification result.Simulation results show that the proposed method has better performance in preventing passive eavesdropping and active attack,and the randomness of key stream is greatly improved and the rate of authentication leak detection is reduced by half.

With the extensive use of gastroscopy as well as colonoscopy, the detectable rate of gastroenteropancreatic neuroendocrine neoplasm(GEP-NEN) has increased substantially. In recent years, the nomination, diagnosis and management of GEP-NEN have changed tremendously. Nowadays, the single-mode treatment is unable to bring the greatest benefit to patients. Instead, multidisciplinary comprehensive treatment model for the promotion and regulation of GEP-NEN diagnosis and treatment is of great significance. This paper is an overview of the related articles and latest clinical consensus(2017) both at home and abroad, which improves the identification of these rare tumors. Additionally, it lays the foundation for clinical diagnosis, treatment as well as prognosis of large sample in future.

Moyamoya disease (MMD) is a chronic progressive obstructive cerebrovascular disease. At present, the etiology and pathogenesis of MMD are still not clear. Recently, many studies confirmed the genetic susceptibility of MMD and reported that the genetic factors are more important than acquired causes. We summarize the domestic and foreign studies on the genetics of MMD, and expect to provide a guidance for early diagnosis and precise treatment. DOI: 10.3969/j.issn.1672-6731.2017.12.012

DOI: 10.3969/j.issn.1672-6731.2017.04.012

Forsterite raw material for ceramic proppant was synthesized by solid-phase sintering method with magnesite tailings and silica as raw materials, which is not only beneficial to the secondary resource utilization of magnesite tailings, but also can replace natural forsterite as raw material for ceramic proppant, providing a new direction for the preparation of raw material for ceramide proppant. The effects of different firing temperatures on the properties of synthetic forsterite were investigated by characterization of phase composition, microstructure and cold physical properties. The acid solubility of samples at different firing temperatures was compared. The results show that when the firing temperature are 1 400 ~1 550 °C for 3 h, the main phase of samples is forsterite. With the firing temperature increases, the grain size of forsterite increases continuously, which improves the cold physical properties and acid resistance of samples. However, an excessively high firing temperature lead to an increase of glassy phase content in samples, affecting its performance. When the firing temperature is 1 500 °C, cold mechanical properties of samples reach the maximum value, and acid solubility is the lowest. [ABSTRACT FROM AUTHOR]

It is of great theoretical and practical significance to study the dry matter accumulation and translocation properties of ratoon rice for further understanding the physiological mechanism of yield formation and exploring the potential of yield increase. In this study, two rice varieties, Jiafuzhan (conventional indica rice) and Yongyou 2640 (indica-japonica hybrid rice), popularly planted in Southeast China, were used as the test materials. The ratooning and main rice crops of the two cultivars were regulated to be heading and ripening in the similar temperature condition of late autumn. Differences of photosynthetic physiology, hormone content, dry matter production, NSC translocation, and 13C assimilate in aboveground and underground parts of ratooning rice and its main crop synchronized heading in late season were compared. The results showed that, compared with main crop (late season) synchronized in rice heading time, the growth period of ratooning rice of the two varieties was 50% shorter, but they had 50% increase of effective panicles and 10% increase of harvest indexes, so the final yield could still reach 55%-65% of the control yield; the photosynthetic rate and SPAD value of the ratooning rice at the early stage of grain filling were significantly higher, but they turned to be significantly lower from 20 days after full heading to maturity; the content of ZR and IAA in ratooning rice were higher at the full heading stage, but lower later; the content of ABA in ratooning rice was 10%-20% higher from full heading stage to 10 days or 20 days after full heading, while the content of GA3 in ratooning rice was generally lower; NSC translocation rates of stubble, leaf and stem-sheath of the two tested varieties were as high as 67%-78%, 59%-67%, and 52%-61%, respectively, and the contribution rate of NSC translocation to yield was also as high as 10%-18%, respectively. The distribution rate of 13C photochemical compounds in panicle of ratooning rice at maturity stage was up to 20.83%, and the translocation of 13C assimilates to underground part of ratooning rice was reduced by 5%, resulting in more effective panicles and higher harvest index. Therefore, ratooning rice can reduce translocation and allocation of photoassimilates to rhizosphere soil, improve harvest index, lessen CH4, and other greenhouse gas emissions, which is a high-benefit and environment-friendly rice cropping pattern. [ABSTRACT FROM AUTHOR]

It is of great significance to study the uplift bearing characteristics of suction caisson foundations for the safe service performance of offshore tension leg platform (TLP) and multi-leg wind turbine. Based on the secondary development of ABAQUS, a numerical model of suction caisson foundations considering strain softening and rate effect of soft clay is established. The numerical results are compared with the theoretical and experimental results to verify the reliability of the numerical model. The simulation results show that the change of soft clay strain softening parameters has less than five percent influence on the peak of uplift load, while the rate effect has obvious influence on the peak of uplift load and the difference caused by the change of rate effect parameters is more than forty percent. The peak of uplift load increases linearly with the caisson outer wall roughness, and the effect of strain softening and rate effect on the uplift load caused by the caisson outer wall roughness can be ignored. For the caisson groups foundation, the caisson group effect becomes obvious with the decrease of caisson spacing, and the bearing capacity can be reduced by up to ten percent. When the caissons spacing is more than one and a half times of the caisson diameter, the caisson groups effect can be ignored. [ABSTRACT FROM AUTHOR]

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Glioma is the most common primary tumor of central nervous system (CNS), about 50% of which is extremely malignant glioblastoma (GBM). GBM is the most common primary malignant brain tumors in adults. Surgery, radiotherapy and chemotherapy (most with temozolomide) are regarded as the conventional treatments, but they failed to significantly prolong the survival of GBM patients. The standard treatment of GBM lacks of specificity, and tumor cells are resistant to radiotherapy or alkylating agents, thus recurrence of GBM is inevitably and the overall prognosis is quite poor. Currently, tumor immunotherapy is emerging and booming, which provides more treating options for GBM. This study, hence, reviews the current status of immunotherapy among the comprehensive treatments of glioma, at the same time indicates the potential targets of immunotherapy, further to update treatment strategies and explain the potential for the resistance of immunotherapy. [ABSTRACT FROM AUTHOR]

There exist some problems such that the user spending order is fixed in the transferable E-cash system, and the transferable number is restricted. Using the Groth-Sahai proof system. Ghadafi group blind signature and commitment to commitment, a transferable E-cash system of equal length with optimal anonymity and arbitrarily spending order was designed in a standard model. It was arranged that, based on the commitment to commitment, the users could compress the transferable serial number, and the length of the E-cash could be constant in the spending protocol, based on the Ghadafi group blind signature, the arbitrarily spending order could be achieved. Finally, the security of the transferable E-cash system was verified in the standard model. Results show its unforgeability, anonymity, identification of double spender and exculpability. [ABSTRACT FROM AUTHOR]

Objective To investigate the relationship between beta enolase gene two point rs121918403 (G/A), rs121918404 (G/A) polymorphism with skeletal muscle Atrophy in the patient with chronic obstructive pulmonary disease (COPD). Method Beta enolase genes were assayed by polymerase chain and one-way directed sequencing methods between 120 COPD patients and 60 age-matched controls in Kunming. Result There was no mutation in rs121918403 (G/A) and rs121918404 (G/A) of beta enolase gene in COPD patients and healthy subjects. Conclusion SNPs of two mutational sites of beta enolase are not correlated to skeletal muscle atrophy in COPD patients in Kunming. [ABSTRACT FROM AUTHOR]

It was difficult to measure the dynamic position for large rotary parts accurately and the cost of measurement was high. However, to avoid these problems, according to the law of actual motion of large rotary parts, this paper presented a novel real-time detection method, which built constant velocity model and "current" statistical model, and then established interacting multiple model (IMM) algorithm based on the two models. Every dynamic position variable detected by multi-grating sensors was computed by the IMM algorithm to get the final fusion value, and the final fusion values were weighted estimated by using filtering error covariance matrix. The method based on IMM algorithm and optimal weighted estimation algorithm had a small position error, which was demonstrated by Monte Carlo simulation. And the method was also used to measure the angular position of the hollow shaft of a rocket fairing horizontal riveting apparatus. The experimental result shows that the method has a high position detection accuracy and robustness. [ABSTRACT FROM AUTHOR]

Taking the drought-sensitive Dactylis glomerata line 01998"and drought-tolerant cultivar "Baoxing" as test materials, a pot experiment was conducted to study the effects of drought stress on the seedlings root growth, physiological characteristics, and leaf photosynthesis, aimed to approach the differences in the drought-tolerance mechanism of different D. glomerata lines (cultivars). Under drought stress, the root vitality and root number of "01998" and "Baoxing" presented a trend of increased first and decreased then. When the soil relative moisture content decreased to 30%, the root vitality and root number of "01998" and "Baoxing" increased significantly and reached the maximum. Drought stress decreased the relative water content, leaf chlorophyll content, net photosynthesis, transpiration, and stomatal conductance, but increased the electric conductivity and intercellular CO2 concentration of "01998" and "Baoxing". Under drought stress, the leaf area per plant of both "01998" and "Baoxing" decreased, and the underground and aboveground plant biomass of "01998" decreased while that of "Baoxing" had less change. [ABSTRACT FROM AUTHOR]

The stamping forming and crash simulations of vehicle body panels have different requirements on the mesh of finite element analysis model. For achieving the transfer of variables between different types of mesh model, a new mesh variables mapping technique based on inverse isoparametric mapping algorithm is proposed, in which the real state variables (such as thickness, stress and strain) of panel after the change in material properties during sheet metal forming process are accurately mapped into the model for crash simulation by accurately locating the nodes of crash simulation model in stamping model and the interpolation of node variables between mesh models. This method is applied to the crash simulation for a car front bumper and the results show that the method can well realize the mesh preprocessing in finite element analysis and accurately transfer mesh variables, while introducing stamping effects into crash simulation and hence improve the efficiency and accuracy of vehicle crash simulation. [ABSTRACT FROM AUTHOR]

Pot experiments were carried out to study the effects of NaCl stress on growth, ion distribution and chlorophyll fluorescence characteristics of Euphorbia lathyris L. The concentration gradient of NaCl was 0, 25, 50, 75, 100, 150, 200 and 250mmol • L-1. Results showed that plant fresh weights, dry weights and heights of seedlings decreased slightly at 25mmol • L-1 NaCl, but decreased significantly when NaCl concentration > 50mmol • L-1 High concentration of NaCl led to decrease of plant ions of K+, Mg2+ and Ca2+, and especially sharp decrease of the ratios of K+/ Na+, Ca / Na+, and Mg2+ / Na+. High concentration of NaCl also led to decrease of minimal fluorescence (Fo), maximum fluorescence (Fm), and PS II actual fluorescence efficiency. Significant Fo and Fm changes happened at higher salt stress (e. g. >25mmol • L-1 NaCl). It could be concluded that E. lathyris damaged photo - inhibition by NaCl stress. [ABSTRACT FROM AUTHOR]