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Antarctic krill (Euphausia Superba) has a high nutritional value; however, due to its autolysis characteristics and easy deterioration characteristics after heating, which leads to difficulties in processing, canned Antarctic krill is one of the few products that exist. However, canned Antarctic krill have a rough taste, high hardness, and poor palatability. Therefore, there is a need to improve its quality. In recent years, the good performance of basic amino acids as a Phosphate-free additives in improving the product quality of foods has indicated their broad application prospect. The purpose of this study was to evaluate the effect of basic amino acid (L-arginine (Arg), L-lysine (Lys), and L-histidine (His)) pretreatment on enhancing the quality of canned Antarctic krill. Low-field nuclear magnetic resonance, magnetic resonance imaging, and textural profile analyses, color, scanning electron microscopy, thiobarbituric acid reaction substances (TBARS), pH, and sensory evaluation were used to determine the indices of krill meat at different pretreatment conditions and processing stages. The results showed that compared to the sodium tripolyphosphate pretreatment group, krill meat pretreated with Lys had a larger peak area of immobile water, higher pseudo-color image brightness after sterilization of krill meat, a more complete microstructure network. Additionally, it had the best water-holding capacity, lower hardness and TBARS values, and significantly higher a* values, indicating that Lys effectively improved the texture and color of krill, protecting the microstructure, and reducing the degree of oxidation. Sensory evaluation results showed that the Lys-treated canned Antarctic krill had a better flavor and texture compared to other canned products. The results of this study suggest that Lys can provide a regulatory strategy for effectively enhancing the quality of canned Antarctic krill.

Antarctic krill (Euphausia superba) is an important source of biomass and high-quality protein. However, heat treatment of Antarctic krill negatively impacts its quality and compromises its utilization in the food industry. This study aimed to investigate the mechanisms underlying changes in Antarctic krill meat characteristics and physicochemical properties treated at different temperatures and holding times. Findings indicate that at higher temperatures and holding times, hardness and cooking loss of Antarctic krill meat increased dramatically. The low-field nuclear magnetic resonance (LF-NMR) analysis revealed that the loss of immobile water increased, whereas SDS-PAGE analysis showed that the content of myosin heavy chain decreased significantly, and that protein degradation occurred. Fourier transform infrared spectroscopy (FT-IR) and intrinsic fluorescence spectra indicated that α-helix motifs were transformed into β-sheets, and that more hydrophobic groups were exposed. The scanning electron microscopy (SEM) results showed that Antarctic krill meat formed corrugated folded regions after heat treatment without forming a three-dimensional water-entrapped structure, which led to significant water loss, resulting in rapid deterioration Antarctic krill meat. These results provide the basis for a deeper understanding of processing characteristics of Antarctic krill meat.

This study was devoted to an investigation of the effects of the average temperature and dwell on the thermal-mechanical fatigue (TMF) behaviour of P92 steel at elevated temperatures in the range of 350–650 °C. The results revealed that increased average temperature decreased the in-phase TMF (IPTMF), out-of-phase TMF (OPTMF), and isothermal fatigue (IF) life values, and its effect was more significant in the range of 400–450 °C. The effect of a short dwell time on the IPTMF life was dependent on the form of dwell, because tensile dwell decreased the IPTMF life and symmetric dwell increased the IPTMF life. Both creep stress relaxation (CSR) and dynamic strain ageing (DSA) were detected under IPTMF cycling. The application of dwell enhanced the CSR phenomenon. In contrast, the DSA effect was restrained, which was beneficial for fatigue resistance. The appearance of crack tip blunting and crack branching because of symmetric dwell indicated the retardation of crack propagation under the combined effects of enhanced CSR and the disappearance of the DSA phenomenon. In all cases, the transformation of lath structures into substructures was the dominant deformation mechanism. In addition, the equiaxial subgrain grew with increases in the strain amplitude and dwell time. Finally, the application of the current life models to P92 steel fatigue life prediction under both IF and TMF cycling were evaluated. Because of the insufficiency of the current models, a modified Coffin–Manson model is proposed by incorporating the mean stress and temperature into power law forms. Keywords: Thermal-mechanical fatigue, Creep stress relaxation, Dynamic strain ageing, Fatigue life prediction

Four new indole-terpenoids (1–4) named encindolene A, 18-O-methyl-encindolene A, encindolene B, and encindolene C, as well as three known analogs (5–7), were isolated from the fungus Penicillium sp. HFF16 from the rhizosphere soil of Cynanchum bungei Decne. The structures of compounds including absolute configurations were elucidated by spectroscopic data and electronic circular dichroism (ECD) analysis. Anti-inflammatory activity evaluation revealed that compounds 1–7 inhibit the production of nitric oxide with IC50 values of 79.4, 49.7, 81.3, 40.2, 86.7, 90.1, and 54.4 μM, respectively, and decrease the levels of tumor necrosis factor-α, interleukin-6 contents in lipopolysaccharide-induced RAW264.7 macrophages.

The ultra-supercritical power generation technology with high energy efficiency and low emissions is one of the important ways to solve the current increasingly prominent energy problems in the context of international development requirements for carbon neutrality and the increasingly prominent energy shortage. Because of its excellent resistance to high temperature corrosion and organizational stability, S31042 is commonly employed in the most severe working environment of ultra-supercritical units. Due to its great resistance to high-temperature corrosion and organizational stability, S31042 is commonly employed in the most demanding components of ultra-supercritical units such as high-temperature reheaters and high-temperature superheaters. Various characterisation approaches were employed in this research to reflect the microstructure of S31042 heat-resistant steel in service under various time length conditions, and the hardness of S31042 heat-resistant steel was assessed under the corresponding service conditions. The results showed that the hardness of S31042 increased significantly with increasing service time, from around 160 Hv at the time of non-service to nearly 220 Hv after 75360 hours of service. The continuous distribution of uniformly sized M23C6 phase on the grain boundaries of S31042 developed toward grain coarsening after service, but the precipitation strengthening effect produced by the nanoscale secondary NbCrN phase appearing in the grains was the main reason for the increase of the hardness value of S31042, according to the microstructure of the material.

In this paper, the evolution of microstructure and mechanical properties of Super304H during aging at 650 °C is investigated, and the effect between microstructure evolution and properties change a...

Ultra-supercritical power generation technology is one of the main solutions to the many contradictory problems of carbon emissions and environmental protection in coal-fired power plants. S31042 austenitic heat-resistant steel has become a typical material for high-temperature components used in ultra-supercritical units because of its good high-temperature creep properties and high-temperature corrosion resistance. In this study, typical characterization techniques such as SEM (Scanning Electron Microscopy), TEM (transmission electron microscopy), and EBSD (Electron Backscattered Diffraction) were used to observe the microstructure of S31042 austenitic heat-resistant steel, while the room-temperature tensile and high-temperature tensile properties of the material were tested under the corresponding conditions. The results show that the grain of S31042 heat-resistant steel after service is the same as that of the non-service samples, which is still twinned austenite. The room-temperature tensile properties and high-temperature tensile properties of S31042 after long service were almost unchanged.

Two new thio-compounds named aspergerthinol A and B (1 and 2) and two new monoterpenes named aspergerthinacids A and B (3 and 4) were isolated from the fungus Aspergillus sp. CYH26 from the rhizosphere soil of Cynanchum bungei Decne. The structures of compounds were elucidated by spectroscopic data and quantum NMR and ECD calculations. Compounds 1 and 2 represented a new family of sulfur containing natural products with a 3-methyl-4H-cyclopenta[b]thiophen-4-one skeleton. Compounds 1–4 showed inhibitory activities against nitric oxide (NO) with IC50 values of 38.0, 19.8, 46.3, and 56.6 μM, respectively.

Let Z p be the ring of p-adic integers, λ the Haar measure on p Z p and a n ( x ) the n-th digit of Schneider's p-adic continued fractions of x ∈ p Z p . We prove that a n ( x ) are independent and identically distributed with respect to λ. Moreover, we obtain the Hausdorff dimensions of some sets defined by the growth rate of a n ( x ) and the sum of a n ( x ) respectively. Such dimensional results are different from that in the cases of real numbers and formal series.

The influence of phase angle varying from 0° (in-phase, IP), 90° (clockwise diamond, CD) and 180° (out-of-phase, OP) on thermal-mechanical fatigue behavior and lifetime of P92 steel has been investigated in present paper. Thermal-mechanical fatigue (TMF) tests were conducted under mechanical strain control whose amplitudes were 0.4%, 0.6% and 0.8% with thermal cycles between 550 °C and 650 °C. For comparison, isothermal fatigue (IF) tests also have been achieved at maximum circular temperature of 650 °C under the three mechanical strain amplitudes. Both thermal-mechanical and isothermal fatigue tests were finished with the equal mechanical strain ratio of Re = −1 and cycle period of 120 s. Results show that the sequence of failure lifetime is N f OP N f IP N f CD N f IF for a given mechanical strain amplitude. Fractographic and microstructural investigations show that cracks initiate and propagate transgranularly for both TMF and IF tests and the creep relaxation and oxidation phenomenon contribute a lot in the process of microstructural damage. Three life prediction models were selected and compared to predict failure lifetime, in which the Ostergren model related to phase angle was modified to achieve a better predictive precision.

In the present work, thermomechanical fatigue behavior and life prediction of P92 steel welded joints under various mechanical strain amplitudes and phase angles are investigated. Results demonstrate that the welded joints exhibit significant cyclic softening during fatigue process and the thermomechanical fatigue life is strain amplitude and phase angle dependent. The decrease in strain amplitude and the increase in phase angle induce the increase in fatigue life. Fracture analysis indicates that the fracture position changes significantly with the strain amplitude and phase angle. Finally, a modified energy-based life prediction model is proposed by considering the effects of phase angle and mean stress.

The attitude control of staring-imaging satellite using permanent magnet momentum exchange sphere (PMMES) is studied in this paper. The desired attitude and desired angular velocity of the satellite are analyzed firstly. The PMMES is applied to meet the requirement of miniaturization for staring-imaging satellite. In order to overcome the drawbacks of the control law based on the Lagrange dynamics model, the Kane method is applied to the PMMES for the first time, and the relationship between the control torque and generalized angular velocity of the PMMES is established directly. Then the dynamic model of staring-imaging satellite with the PMMES is established, and the kinematics model of satellite attitude is deduced. In addition, a PD controller based on disturbance observer is designed to achieve satellite staring task, and the sliding mode controller of the PMMES is designed to suppress the parameter perturbation and the external disturbance. Finally, the simulation results show the validity of the designed control law.

Fine particulate matter (PM2.5) has been an important environmental issue because it can seriously harm human health and can adversely affect the economy. It poses a problem worldwide and especially in China. Based on data of PM2.5 concentration and night light data, both collected from satellite remote sensing during 1998&ndash, 2013 in China, we identify the socio-economic determinants of PM2.5 pollution by taking into account the spatial flow and diffusion of regional pollutants. Our results show PM2.5 pollution displays the remarkable feature of spatial agglomeration. High concentrations of PM2.5 are mainly found in Eastern China (including Shandong, Jiangsu, and Anhui provinces) and the Jing-Jin-Ji Area region in the north of China (including Beijing, Tianjin, and Hebei provinces) as well as in the Henan provinces in central China. There is a significant positive spatial spillover effect of PM2.5 pollution, so that an increase in PM2.5 concentration in one region contributes to an increase in neighboring regions. Whether using per capita GDP or nighttime lighting indicators, there is a significant N-shaped curve that relates PM2.5 concentration and economic growth. Population density, industrial structure, and energy consumption have distinct impacts on PM2.5 pollution, while urbanization is negative correlated with PM2.5 emissions. As a result, policies to strengthen regional joint prevention and control, implement cleaner manufacturing techniques, and reduce dependence on fossil fuels should be considered by policy makers for mitigating PM2.5 pollution.

Let [Formula: see text] be a real number. For any [Formula: see text], let [Formula: see text] be the maximal length of consecutive zero digits between the first [Formula: see text] digits of [Formula: see text]’s [Formula: see text]-expansion. We prove that for Lebesgue almost all [Formula: see text], [Formula: see text]. Also the Hausdorff dimensions of the related exceptional sets are determined.

Grade 92 heat-resistant steel is an important material for ultra-supercritical units. The degradation of the P92 properties affects the safety of structural components during long-term service. In this paper, the microstructural evolution of P92 depending on different service times was quantitatively studied using scanning electron microscopy and transmission electron microscopy. The effect of each strengthening mechanism on the strength of P92 is discussed. The results show that the dimensions of M23C6 and Laves phases increase with increasing service time, but the growth rate of the Laves phase is higher than that of M23C6 and the size of MX carbonitrides remains almost unchanged. The width of the martensite lath increases from the initial 350 nm–750 nm after 70,000 h of service. The dislocation density significantly decreases and then stabilizes with increasing service time. The high- and room temperature tensile properties worsen and then stabilize during long-term service. The thermal yield stress of P92 during service was calculated. The results show that the high-temperature strength of P92 steel is mainly affected by lath and dislocation hardening during the initial service time; as the service time increases, the strengthening mechanism transforms into lath and precipitate hardening.

Climatic fluctuations during the Quaternary significantly affect many species in their intraspecific divergence and population structure across northwest China. In order to investigate the impact of climate change on herbaceous plants, we studied Panzerina lanata (Lamiaceae), a widely distributed species. Sequences of two chloroplast DNA (cpDNA) intergenic spacers (trnH-psbA and rpoB-trnC) and a nuclear ribosomal region (nrDNA, ITS) were generated from 27 populations of Panzerina lanata and resulted in the identification of seven chloroplast haplotypes and thirty-two nuclear haplotypes. We applied AMOVA, neutrality test and mismatch distribution analysis to estimate genetic differentiation and demographic characteristics. The divergence times of the seven cpDNA haplotypes were estimated using BEAST. Our results revealed high levels of genetic diversity (cpDNA: Hcp = 0.6691, HT = 0.673; nrDNA: Hnr = 0.5668, HT = 0.577). High level of genetic differentiation (GST = 0.950) among populations was observed in the cpDNA sequences, while the genetic differentiation values (GST = 0.348) were low in nuclear sequences. AMOVA results revealed major genetic variation among the three groups: northern, central, and eastern group. However, the genetic differentiation in ITS data was not found. The species distribution modeling and demographic analysis indicated that P. lanata had not experienced recent range expansion. The occurrence of divergence between seven cpDNA haplotypes, probably during Pleistocene, coincides with aridification and expansion of the desert across northwest China that resulted in species diversification and habitat fragmentation. In addition, we discovered that the deserts and the Helan Mountains acted as effective geographic barriers that promoting the intraspecific diversity of P. lanata.

Climatic fluctuations during the Quaternary significantly affect many species in their intraspecific divergence and population structure across northwest China. In order to investigate the impact of climate change on herbaceous plants, we studiedPanzerina lanata(Lamiaceae), a widely distributed species. Sequences of two chloroplast DNA (cpDNA) intergenic spacers (trnH-psbAandrpoB-trnC) and a nuclear ribosomal region (nrDNA, ITS) were generated from 27 populations ofPanzerina lanataand resulted in the identification of seven chloroplast haplotypes and thirty-two nuclear haplotypes. We applied AMOVA, neutrality test and mismatch distribution analysis to estimate genetic differentiation and demographic characteristics. The divergence times of the seven cpDNA haplotypes were estimated using BEAST. Our results revealed high levels of genetic diversity (cpDNA:Hcp = 0.6691,HT= 0.673; nrDNA:Hnr = 0.5668, HT= 0.577). High level of genetic differentiation (GST= 0.950) among populations was observed in the cpDNA sequences, while the genetic differentiation values (GST= 0.348) were low in nuclear sequences. AMOVA results revealed major genetic variation among the three groups: northern, central, and eastern group. However, the genetic differentiation in ITS data was not found. The species distribution modeling and demographic analysis indicated thatP. lanatahad not experienced recent range expansion. The occurrence of divergence between seven cpDNA haplotypes, probably during Pleistocene, coincides with aridification and expansion of the desert across northwest China that resulted in species diversification and habitat fragmentation. In addition, we discovered that the deserts and the Helan Mountains acted as effective geographic barriers that promoting the intraspecific diversity ofP. lanata.

A model to calculate the welding temperature and residual stress was built using finite element code ABAQUS, and a subroutine of creep damage was also developed. Based on the coupling of welding residual stress and creep damage, the welding residual stress and creep damage of a tube made of Cr5Mo steel were simulated. This method can obtain the distributions of complex residual stress, creep damage and stress relaxation, which provide a reference for discussing the effect of residual stress on creep damage. The results show that the welding residual stress is very large at initial stage, then it is relaxed in a short time at high temperature. The distribution of creep and damage is mainly decided by the as-welding residual stress. Welding residual stress has a great effect on the creep and damage, which provides a reference for the design and life prediction of high temperature component.

Creep–fatigue interaction damage evolution of the nuclear engineering materials modified 9Cr–1Mo steel is studied with Continuum Damage Mechanics (CDM) theory. Based on the Norton creep damage and fatigue dissipate potential theory, an effective stress controlled creep–fatigue interaction damage model has been developed in this paper, in which the creep and fatigue damage function are both considered as nonlinear variables. The damage evolution function consists of the stress amplitude and the range of mean strain. The damage parameters in the model have clear physical meaning and can be determined easily. A stress controlled creep–fatigue interaction experiment has been performed with the P91 steel to obtain the damage model. The experimental results indicated that the damage model is applicable to describe the damage evolution for creep–fatigue interaction.

Creep-fatigue interaction is a principal cause of failures of many engineering components under high temperature and cyclic loading. In this work, stress controlled creep-fatigue interaction tests are carried out for modified 9Cr-1Mo (P91) steel. In order to study the damage mechanism of P91 steel under creep-fatigue interaction, Scanning Electron Microscopy (SEM) of specimen fracture morphology and in-situ observation experiments were conducted. Based on the ductility exhaustion theory and creep-fatigue interaction tests data, the modified ductility exhaustion life prediction model was developed. The predicted results are in a good agreement with the experiment. By comparison with frequency separation model, the life predicted by ductility exhaustion model is better than frequency separation model obviously. The results show that different stress amplitude and mean stress have great effect on the fracture damage mechanism when the hold time is invariable. By the SEM analysis of fracture morphology, the damage characters of creep, creep-fatigue interaction and fatigue can be partitioned. The specimen crack initiation source is the modified 9Cr-1Mo steel inclusion. Therefore, this work can provide a reference of life prediction and design for high temperature materials and components.

This paper introduces a method combining 2D discrete wavelet transform (2-DWT) with energy threshold method to solve the data compression of power quality detection data. In this paper the high frequency signals and noise signals are decomposed into three different directions by making use of 2D db wavelet transform to process matrix data with row convolution and line convolution, and the energy of signals are concentrated on a few wavelet coefficients. Through improving energy threshold method, the thresholds are set up by energy correction coefficient. It assures the remainder energy over 99%. Thus, the distortion ratio of reconstructed signals is smaller and the eliminating noise of disturbing signals is adaptive. Results of simulations with six disturbing signals indicate this method has a higher compression ratio and a better ability to eliminate noise compared to compressive results of wavelet packet. (6 pages)

One of the major problems in knowledge discovery is producing too many trivial and uninteresting patterns. The measurement of interestingness is divided into subjective and objective measures and used to address the problem. In this paper, we propose a novel method to discover interesting patterns by incorporating the domain user’s preconceived knowledge. The prior knowledge constitutes a set of hypothesis about the domain. A new parameter called the distance is proposed to measure the gap between the user’s existing hypothesis and system-generated knowledge. To evaluate the practicality of our approach, we apply the proposed approach through some real-life data sets and present our findings.

A mutation in coagulant factor V gene, a substitution in the 3' untranslated region of prothrombin gene, and a variant in 5,10-methylenetetrahydrofolate reductase (MTHFR) gene have been reported to be related to venous thromboembolism in Caucasians, but this relationship remains in debate in other populations. In this case-control study, we aimed to determine the prevalence of these three mutations in the Chinese population and investigate whether they are associated with pulmonary thromboembolism. The subjects consisted of 90 patients with pulmonary thromboembolism and 143 age- and sex-matched healthy controls. Traditional risk factors for venous thrombosis and pulmonary thromboembolism were investigated as well. We found that the frequencies of varicose vein, phlebitis, trauma, and surgery were significantly higher in cases than in controls. Of all subjects, none was a carrier of coagulant factor V gene G1691A mutation or prothrombin gene G 20210A mutation, which are common point mutations in Caucasians, while the frequency of MTHFR gene 677T allele exceeded 55% in cases (56.7%), controls (55.2%), and all subjects (55.8%) studied. The homozygous mutation rate of MTHFR gene was over 30% in both cases (33.3%) and controls (32.2%), but no significant difference was found in genotype distribution (chi(2)=0.100, P=0.951). Model fitting using logistic regression did not find that MTHFR gene C677T mutation was associated with pulmonary thromboembolism, consistent with the results of stratification analysis. In conclusion, coagulant factor V gene G1691A mutation and prothrombin G20210A mutation are very rare, while MTHFR C677T mutation is very common, and all of them are not associated with pulmonary thromboembolism in the Chinese population.