Using molecular dynamics methods,simulations of collision cascades in polycrystalline tungsten(W)have been conducted in this study,including different primary-knock-on atom(PKA)directions,grain sizes,and PKA energies ...Using molecular dynamics methods,simulations of collision cascades in polycrystalline tungsten(W)have been conducted in this study,including different primary-knock-on atom(PKA)directions,grain sizes,and PKA energies between 1 keV and 150 keV.The results indicate that a smaller grain size leads to more defects forming in grain boundary regions during cascade processes.The impact of high-energy PKA may cause a certain degree of distortion of the grain boundaries,which has a higher probability in systems with smaller grain sizes and becomes more pronounced as the PKA energy increases.The direction of PKA can affect the formation and diffusion pathways of defects.When the PKA direction is perpendicular to the grain boundary,defects preferentially form near the grain boundary regions;by contrast,defects are more inclined to form in the interior of the grains.These results are of great significance for comprehending the changes in the performance of polycrystalline W under the high-energy fusion environments and can provide theoretical guidance for further optimization and application of W-based plasma materials.展开更多
Polynomial Chaos Expansion(PCE)has gained significant popularity among engineers across various engineering disciplines for uncertainty analysis.However,traditional PCE suffers from two major drawbacks.First,the ortho...Polynomial Chaos Expansion(PCE)has gained significant popularity among engineers across various engineering disciplines for uncertainty analysis.However,traditional PCE suffers from two major drawbacks.First,the orthogonality of polynomial basis functions holds only for independent input variables,limiting the model’s ability to propagate uncertainty in dependent variables.Second,PCE encounters the"curse of dimensionality"due to the high computational cost of training the model with numerous polynomial coefficients.In practical manufacturing,compressor blades are subject to machining precision limitations,leading to deviations from their ideal geometric shapes.These deviations require a large number of geometric parameters to describe,and exhibit significant correlations.To efficiently quantify the impact of high-dimensional dependent geometric deviations on the aerodynamic performance of compressor blades,this paper firstly introduces a novel approach called Data-driven Sparse PCE(DSPCE).The proposed method addresses the aforementioned challenges by employing a decorrelation algorithm to directly create multivariate basis functions,accommodating both independent and dependent random variables.Furthermore,the method utilizes an iterative Diffeomorphic Modulation under Observable Response Preserving Homotopy regression algorithm to solve the unknown coefficients,achieving model sparsity while maintaining fitting accuracy.Then,the study investigates the simultaneous effects of seven dependent geometric deviations on the aerodynamics of a high subsonic compressor cascade by using the DSPCE method proposed and sensitivity analysis of covariance.The joint distribution of the dependent geometric deviations is determined using Quantile-Quantile plots and normal copula functions based on finite measurement data.The results demonstrate that the correlations between geometric deviations significantly impact the variance of aerodynamic performance and the flow field.Therefore,it is crucial to consider these correlations for accurately assessing the aerodynamic uncertainty.展开更多
To investigate the design strategy of highly loaded tandem cascades at both the midspan and endwall,the overall performance and flow mechanisms of four typical tandem cascades based on the optimization were analyzed f...To investigate the design strategy of highly loaded tandem cascades at both the midspan and endwall,the overall performance and flow mechanisms of four typical tandem cascades based on the optimization were analyzed from multiple perspectives numerically.The results show that the interference effects on the Front Blade(FB)and Rear Blade(RB)should not be overlooked during the design phase,and the design strategies at the midspan and endwall are completely different.At the midspan,the optimization aims to increase the interference effects and the strength of the gap jet while maintaining the same load on the FB and RB.However,the endwall optimal airfoil exhibits weakening interference effects,advancement of the gap jet location,and load transfer from the FB to RB.Through further analysis of flow characteristics,the midspan optimal airfoil is beneficial for inhibiting the low-energy fluid from interacting with the suction surface of RB under the design condition,but results in earlier occurrence of corner stall.The endwall optimal airfoil helps suppress the development of the secondary flow and delay the onset of corner stall.Furthermore,by combining the benefits of these two design approaches,additional forward sweep effects are achieved,further enhancing the performance of the tandem cascade.展开更多
This article describes the effects of some factors on the tip clearance flow in axial linear turbine cascades. The measurements of the total pressure loss coefficient are made at the cascade outlets by using a five-ho...This article describes the effects of some factors on the tip clearance flow in axial linear turbine cascades. The measurements of the total pressure loss coefficient are made at the cascade outlets by using a five-hole probe at exit Mach numbers of 0.10, 0.14 and 0.19. At each exit Mach number, experiments are performed at the tip clearance heights of 1.0%, 1.5%, 2.0%, 2.5% and 3.0% of the blade height. The effects of the non-uniform tip clearance height of each blade in the pitchwise direction are also studied. The results show that at a given tip clearance height, generally, total pressure loss rises with exit Mach numbers proportionally. At a fixed exit Mach number, the total pressure loss augments nearly proportionally as the tip clearance height increases. The increased tip clearance heights in the tip regions of two adjacent blades are to be blame for the larger clearance loss of the center blade. Compared to the effects of the tip clearance height, the effects of the exit Mach number and the pitchwise variation of the tip clearance height on the cascade total pressure loss are so less significant to be omitted.展开更多
The complex and variable nature of traumatic spinal cord inju- ry （SCI） presents a unique challenge for translational research. SCI is not bound by any demographic nor is it limited to specific injury biomechanics.
Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rul...Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rules are (1) for a rotor cascade without shroud band, the total number of nodal points equals that the saddle points on the skin-friction line vector fields in eachpitch range; (2) for an annular or straight cascade with no-clearances at blade ends, the total number of saddle points is two more than that of nodal points on the skin-friction line fields in a pitch; (3) the total number of saddles in the secondary flow fields on cross-sections in cascade is one less than that of nodes; (4) in the section streamline vector fields on a meridian surface penetrating a flow passage, and on leading and trailing edge sections, the total number of nodes is equal to that of saddles; (5) on the streamline vector fields of a blade-to-blade surface, the total number of nodes is one less than that of saddles.展开更多
Molecular dynamics simulations of the displacement cascades in Fe 10%Cr systems are used to sinmlate the primary knocked-on atom events of the irradiation damage at temperatures 300, 600, and 750 K with primary knocke...Molecular dynamics simulations of the displacement cascades in Fe 10%Cr systems are used to sinmlate the primary knocked-on atom events of the irradiation damage at temperatures 300, 600, and 750 K with primary knockedon atom energies between 1 and 15 keV. The results indicate that the vacancies produced by the cascade are all in the central region of the displacement cascade. During the cascade, all recoil Fe and Cr atoms combine with each other to form Fe Cr or Fe Fe interstitial dumbbells as well as interstitial clusters. The number and the size of interstitial clusters increase with the energy of the primary knocked-on atom and the temperature. A few large clusters consist of a large number of lee interstitials with a few Cr atoms, the rest are lee Cr clusters with small and medium sizes. The interstitial dumbbells of Fe lee and Fe-Cr are in the （111）and （110） series directions, respectively.展开更多
C-glycosylation and C-prenylation are two important C-C-bond forming reactions for preparation,diversification and structural modification of natural/unnatural products with pharmacological activities.Here,we describe...C-glycosylation and C-prenylation are two important C-C-bond forming reactions for preparation,diversification and structural modification of natural/unnatural products with pharmacological activities.Here,we described unprecedented enzymatic cascades to C-glycosylate/prenylate different acyl resorcinol derivatives in stepwise,one-pot reactions by combining two promiscuous enzymes,MiCGT,a C-glycosyltransferase,and AtaPT,a prenyltransferase.Five novel bis-C-alkylated products were obtained and structurally identified by MS and NMR spectroscopic data as well as comparison with the literature.This study provided a potential synthetic strategy for synthesizing structurally novel and diverse compounds bearing both C-glycosyl and C-prenyl moieties by a two-step,enzymatic bis-C-alkylation.展开更多
A piecewise potential was constructed with combination of the concentration-dependent EAM(CD-EAM)potential and Ziegler-Biersack-Littmark(ZBL)potential,and the displacement cascades in random Fe-Cr binary alloys with a...A piecewise potential was constructed with combination of the concentration-dependent EAM(CD-EAM)potential and Ziegler-Biersack-Littmark(ZBL)potential,and the displacement cascades in random Fe-Cr binary alloys with a wide range of Cr concentration from 0 to 20%were simulated to evaluate the effect of Cr concentration on defect formation and evolution during the cascades.The Cr concentration has little or no effect on the fraction of vacancy clusters,the number of surviving Frenkel pairs,or the self-interstitial and vacancy cluster sizes and a slight effect on the peak time and peak defect number,but a considerable effect on the Cr enrichment in the peak and surviving defects in the cascaded Fe-Cr alloys.With the increase in Cr concentration,the Cr enrichment in the peak and surviving defects exhibits a downtrend.The higher enrichment degree in the surviving defects than in the peak defects shows more difficult recombination of Cr SIAs with vacancies.展开更多
Porphyromonas gingivalis, is the most prominent member of the bacteria flora associated with pathogenesis of periodontitis, a chronic inflammatory disease resulting in tooth loss. The extent of oral mucosal reaction t...Porphyromonas gingivalis, is the most prominent member of the bacteria flora associated with pathogenesis of periodontitis, a chronic inflammatory disease resulting in tooth loss. The extent of oral mucosal reaction to P. gingivalis invasion relays heavily on Toll-like receptors (TLRs) that recognize structurally common motifs of pathogens and initiate antibacterial responses. Among the virulence factors of P. gingivalis implicated in TLRs activation and triggering inflammatory responses leading to the development of periodontitis is the bacterium cell-wall lipopolysaccharide (LPS). The engagement by the LPS of oral mucosal TLR4 leads to initiation of signaling events characterized by the activation of mitogen-activated protein kinase (MAPK) and IκB-kinase complex (IKK) cascades, induction of phosphoinositide-specific phospholipase C (PLC)/protein kinase C (PKC)/PI3K pathway, up-regulation in TGF-α ectodomain shedding and EGFR transactivation, and the amplification of proinflammatory signals by spleen tyrosine kinase (Syk). These events, in turn, exert their control over transcription factors implicated in the induction of the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) genes that lead to up-regulation in the inflammatory mediators, PGE2 and NO. The systems involved in transcription factors activation, furthermore, remain under additional regulatory control through S-nitrosylation. Moreover, the LPS-induced TLR4 activation provides a docking site for Syk, the activation of which leads to amplification of the inflammatory signals by affecting transcription factors activation and their assembly to transcriptional complexes. Interestingly, the extent of oral mucosal inflammatory response to P. gingivalis remains under modulatory influence by two biologically active peptide hormones, leptin and ghrelin. Therefore, the presence of these multifunctional peptides in oral mucosa and saliva may be of significance in countering the destructive consequences of P. gingivalis—induced chronic mucosal inflammation that characterizes periodontitis.展开更多
This paper briefly describes the basic situation and features of Three Gorges Cascade, discusses the principle,functions, structure of the integrated automation system, and explains advanced techniques and principle a...This paper briefly describes the basic situation and features of Three Gorges Cascade, discusses the principle,functions, structure of the integrated automation system, and explains advanced techniques and principle and associated experiments of its monitoring and control展开更多
To investigate the influence of real leading-edge manufacturing error on aerodynamic performance of high subsonic compressor blades,a family of leading-edge manufacturing error data were obtained from measured compres...To investigate the influence of real leading-edge manufacturing error on aerodynamic performance of high subsonic compressor blades,a family of leading-edge manufacturing error data were obtained from measured compressor cascades.Considering the limited samples,the leadingedge angle and leading-edge radius distribution forms were evaluated by Shapiro-Wilk test and quantile–quantile plot.Their statistical characteristics provided can be introduced to later related researches.The parameterization design method B-spline and Bezier are adopted to create geometry models with manufacturing error based on leading-edge angle and leading-edge radius.The influence of real manufacturing error is quantified and analyzed by self-developed non-intrusive polynomial chaos and Sobol’indices.The mechanism of leading-edge manufacturing error on aerodynamic performance is discussed.The results show that the total pressure loss coefficient is sensitive to the leading-edge manufacturing error compared with the static pressure ratio,especially at high incidence.Specifically,manufacturing error of the leading edge will influence the local flow acceleration and subsequently cause fluctuation of the downstream flow.The aerodynamic performance is sensitive to the manufacturing error of leading-edge radius at the design and negative incidences,while it is sensitive to the manufacturing error of leading-edge angle under the operation conditions with high incidences.展开更多
The circumferentially averaged equation of the inlet flow radial equilibrium in axial compressor was deduced. It indicates that the blade inlet radial pressure gradient is closely related to the radial component of th...The circumferentially averaged equation of the inlet flow radial equilibrium in axial compressor was deduced. It indicates that the blade inlet radial pressure gradient is closely related to the radial component of the circumferential fluctuation（CF） source item. Several simplified cascades with/without aerodynamic loading were numerically studied to investigate the effects of blade bowing on the inlet flow radial equilibrium. A data reduction program was conducted to obtain the CF source from three-dimensional（3D） simulation results. Flow parameters at the passage inlet were focused on and each term in the radial equilibrium equation was discussed quantitatively. Results indicate that the inviscid blade force is the inducement of the inlet CF due to geometrical asymmetry. Blade bowing induces variation of the inlet CF, thus changes the radial pressure gradient and leads to flow migration before leading edge（LE） in the cascades. Positive bowing drives the inlet flow to migrate from end walls to mid-span and negative bowing turns it to the reverse direction to build a new equilibrium. In addition, comparative studies indicate that the inlet Mach number and blade loading can efficiently impact the effectiveness of blade bowing on radial equilibrium in compressor design.展开更多
In this paper, cascading failure is studied by coupled map lattice （CML） methods in preferential attachment community networks. It is found that external perturbation R is increasing with modularity Q growing by sim...In this paper, cascading failure is studied by coupled map lattice （CML） methods in preferential attachment community networks. It is found that external perturbation R is increasing with modularity Q growing by simulation. In particular, the large modularity Q can hold off the cascading failure dynamic process in community networks. Furthermore, different attack strategies also greatly affect the cascading failure dynamic process. It is particularly significant to control cascading failure process in real community networks.展开更多
基金Project supported by the National MCF Energy Research and Development Program of China(Grant No.2018YFE0308101)the National Key Research and Development Program of China(Grant No.2018YFB0704000)+1 种基金the Suqian Science and Technology Program(Grant No.K202337)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.23KJD490001).
文摘Using molecular dynamics methods,simulations of collision cascades in polycrystalline tungsten(W)have been conducted in this study,including different primary-knock-on atom(PKA)directions,grain sizes,and PKA energies between 1 keV and 150 keV.The results indicate that a smaller grain size leads to more defects forming in grain boundary regions during cascade processes.The impact of high-energy PKA may cause a certain degree of distortion of the grain boundaries,which has a higher probability in systems with smaller grain sizes and becomes more pronounced as the PKA energy increases.The direction of PKA can affect the formation and diffusion pathways of defects.When the PKA direction is perpendicular to the grain boundary,defects preferentially form near the grain boundary regions;by contrast,defects are more inclined to form in the interior of the grains.These results are of great significance for comprehending the changes in the performance of polycrystalline W under the high-energy fusion environments and can provide theoretical guidance for further optimization and application of W-based plasma materials.
基金the National Science and Technology Major Project of China(No.J2019-I-0011)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China(No.CX2023057)for supporting the research work.
文摘Polynomial Chaos Expansion(PCE)has gained significant popularity among engineers across various engineering disciplines for uncertainty analysis.However,traditional PCE suffers from two major drawbacks.First,the orthogonality of polynomial basis functions holds only for independent input variables,limiting the model’s ability to propagate uncertainty in dependent variables.Second,PCE encounters the"curse of dimensionality"due to the high computational cost of training the model with numerous polynomial coefficients.In practical manufacturing,compressor blades are subject to machining precision limitations,leading to deviations from their ideal geometric shapes.These deviations require a large number of geometric parameters to describe,and exhibit significant correlations.To efficiently quantify the impact of high-dimensional dependent geometric deviations on the aerodynamic performance of compressor blades,this paper firstly introduces a novel approach called Data-driven Sparse PCE(DSPCE).The proposed method addresses the aforementioned challenges by employing a decorrelation algorithm to directly create multivariate basis functions,accommodating both independent and dependent random variables.Furthermore,the method utilizes an iterative Diffeomorphic Modulation under Observable Response Preserving Homotopy regression algorithm to solve the unknown coefficients,achieving model sparsity while maintaining fitting accuracy.Then,the study investigates the simultaneous effects of seven dependent geometric deviations on the aerodynamics of a high subsonic compressor cascade by using the DSPCE method proposed and sensitivity analysis of covariance.The joint distribution of the dependent geometric deviations is determined using Quantile-Quantile plots and normal copula functions based on finite measurement data.The results demonstrate that the correlations between geometric deviations significantly impact the variance of aerodynamic performance and the flow field.Therefore,it is crucial to consider these correlations for accurately assessing the aerodynamic uncertainty.
基金sponsored by the National Natural Science Foundation of China(Nos.52106057 and 92152301)the Fundamental Research Funds for the Central Universities,China(No.D5000210483)+2 种基金the Foundation of State Level Key Laboratory of Airfoil and Cascade Aerodynamics,China(Nos.D5150210006 and D5050220008)the 111 Project,China(No.B17037)the Key Laboratory of Flow Visualization and Measurement Techniques,AVIC Aerodynamics Research Institute,China(No.D5110220177).
文摘To investigate the design strategy of highly loaded tandem cascades at both the midspan and endwall,the overall performance and flow mechanisms of four typical tandem cascades based on the optimization were analyzed from multiple perspectives numerically.The results show that the interference effects on the Front Blade(FB)and Rear Blade(RB)should not be overlooked during the design phase,and the design strategies at the midspan and endwall are completely different.At the midspan,the optimization aims to increase the interference effects and the strength of the gap jet while maintaining the same load on the FB and RB.However,the endwall optimal airfoil exhibits weakening interference effects,advancement of the gap jet location,and load transfer from the FB to RB.Through further analysis of flow characteristics,the midspan optimal airfoil is beneficial for inhibiting the low-energy fluid from interacting with the suction surface of RB under the design condition,but results in earlier occurrence of corner stall.The endwall optimal airfoil helps suppress the development of the secondary flow and delay the onset of corner stall.Furthermore,by combining the benefits of these two design approaches,additional forward sweep effects are achieved,further enhancing the performance of the tandem cascade.
基金National Natural Science Foundation of China (10377011)
文摘This article describes the effects of some factors on the tip clearance flow in axial linear turbine cascades. The measurements of the total pressure loss coefficient are made at the cascade outlets by using a five-hole probe at exit Mach numbers of 0.10, 0.14 and 0.19. At each exit Mach number, experiments are performed at the tip clearance heights of 1.0%, 1.5%, 2.0%, 2.5% and 3.0% of the blade height. The effects of the non-uniform tip clearance height of each blade in the pitchwise direction are also studied. The results show that at a given tip clearance height, generally, total pressure loss rises with exit Mach numbers proportionally. At a fixed exit Mach number, the total pressure loss augments nearly proportionally as the tip clearance height increases. The increased tip clearance heights in the tip regions of two adjacent blades are to be blame for the larger clearance loss of the center blade. Compared to the effects of the tip clearance height, the effects of the exit Mach number and the pitchwise variation of the tip clearance height on the cascade total pressure loss are so less significant to be omitted.
文摘The complex and variable nature of traumatic spinal cord inju- ry （SCI） presents a unique challenge for translational research. SCI is not bound by any demographic nor is it limited to specific injury biomechanics.
文摘Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rules are (1) for a rotor cascade without shroud band, the total number of nodal points equals that the saddle points on the skin-friction line vector fields in eachpitch range; (2) for an annular or straight cascade with no-clearances at blade ends, the total number of saddle points is two more than that of nodal points on the skin-friction line fields in a pitch; (3) the total number of saddles in the secondary flow fields on cross-sections in cascade is one less than that of nodes; (4) in the section streamline vector fields on a meridian surface penetrating a flow passage, and on leading and trailing edge sections, the total number of nodes is equal to that of saddles; (5) on the streamline vector fields of a blade-to-blade surface, the total number of nodes is one less than that of saddles.
基金Project supported by the National Basic Research Program of China (Grant No. 2007CB209803)the Applied Basic Research Program of Hebei Province,China (Grant No. 10165401P)
文摘Molecular dynamics simulations of the displacement cascades in Fe 10%Cr systems are used to sinmlate the primary knocked-on atom events of the irradiation damage at temperatures 300, 600, and 750 K with primary knockedon atom energies between 1 and 15 keV. The results indicate that the vacancies produced by the cascade are all in the central region of the displacement cascade. During the cascade, all recoil Fe and Cr atoms combine with each other to form Fe Cr or Fe Fe interstitial dumbbells as well as interstitial clusters. The number and the size of interstitial clusters increase with the energy of the primary knocked-on atom and the temperature. A few large clusters consist of a large number of lee interstitials with a few Cr atoms, the rest are lee Cr clusters with small and medium sizes. The interstitial dumbbells of Fe lee and Fe-Cr are in the （111）and （110） series directions, respectively.
基金National Natural Science Foundation of China(Grant Nos.21572277,81573317 and 81703369)CAMS Innovation Fund for Medical Sciences(CIFMS-2016-I2M-3-012)
文摘C-glycosylation and C-prenylation are two important C-C-bond forming reactions for preparation,diversification and structural modification of natural/unnatural products with pharmacological activities.Here,we described unprecedented enzymatic cascades to C-glycosylate/prenylate different acyl resorcinol derivatives in stepwise,one-pot reactions by combining two promiscuous enzymes,MiCGT,a C-glycosyltransferase,and AtaPT,a prenyltransferase.Five novel bis-C-alkylated products were obtained and structurally identified by MS and NMR spectroscopic data as well as comparison with the literature.This study provided a potential synthetic strategy for synthesizing structurally novel and diverse compounds bearing both C-glycosyl and C-prenyl moieties by a two-step,enzymatic bis-C-alkylation.
基金This work was supported by the National Natural Science Foundation of China(Grant numbers:11572135,11772137).
文摘A piecewise potential was constructed with combination of the concentration-dependent EAM(CD-EAM)potential and Ziegler-Biersack-Littmark(ZBL)potential,and the displacement cascades in random Fe-Cr binary alloys with a wide range of Cr concentration from 0 to 20%were simulated to evaluate the effect of Cr concentration on defect formation and evolution during the cascades.The Cr concentration has little or no effect on the fraction of vacancy clusters,the number of surviving Frenkel pairs,or the self-interstitial and vacancy cluster sizes and a slight effect on the peak time and peak defect number,but a considerable effect on the Cr enrichment in the peak and surviving defects in the cascaded Fe-Cr alloys.With the increase in Cr concentration,the Cr enrichment in the peak and surviving defects exhibits a downtrend.The higher enrichment degree in the surviving defects than in the peak defects shows more difficult recombination of Cr SIAs with vacancies.
文摘Porphyromonas gingivalis, is the most prominent member of the bacteria flora associated with pathogenesis of periodontitis, a chronic inflammatory disease resulting in tooth loss. The extent of oral mucosal reaction to P. gingivalis invasion relays heavily on Toll-like receptors (TLRs) that recognize structurally common motifs of pathogens and initiate antibacterial responses. Among the virulence factors of P. gingivalis implicated in TLRs activation and triggering inflammatory responses leading to the development of periodontitis is the bacterium cell-wall lipopolysaccharide (LPS). The engagement by the LPS of oral mucosal TLR4 leads to initiation of signaling events characterized by the activation of mitogen-activated protein kinase (MAPK) and IκB-kinase complex (IKK) cascades, induction of phosphoinositide-specific phospholipase C (PLC)/protein kinase C (PKC)/PI3K pathway, up-regulation in TGF-α ectodomain shedding and EGFR transactivation, and the amplification of proinflammatory signals by spleen tyrosine kinase (Syk). These events, in turn, exert their control over transcription factors implicated in the induction of the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) genes that lead to up-regulation in the inflammatory mediators, PGE2 and NO. The systems involved in transcription factors activation, furthermore, remain under additional regulatory control through S-nitrosylation. Moreover, the LPS-induced TLR4 activation provides a docking site for Syk, the activation of which leads to amplification of the inflammatory signals by affecting transcription factors activation and their assembly to transcriptional complexes. Interestingly, the extent of oral mucosal inflammatory response to P. gingivalis remains under modulatory influence by two biologically active peptide hormones, leptin and ghrelin. Therefore, the presence of these multifunctional peptides in oral mucosa and saliva may be of significance in countering the destructive consequences of P. gingivalis—induced chronic mucosal inflammation that characterizes periodontitis.
文摘This paper briefly describes the basic situation and features of Three Gorges Cascade, discusses the principle,functions, structure of the integrated automation system, and explains advanced techniques and principle and associated experiments of its monitoring and control
基金the National Natural Science Foundation of China(No.51790512)the 111 Project(No.B17037)the National Key Laboratory Foundation,Industry-Academia-Research Collaboration Project of Aero Engine Corporation of China(No.HFZL2018CXY011-1)and MIIT。
文摘To investigate the influence of real leading-edge manufacturing error on aerodynamic performance of high subsonic compressor blades,a family of leading-edge manufacturing error data were obtained from measured compressor cascades.Considering the limited samples,the leadingedge angle and leading-edge radius distribution forms were evaluated by Shapiro-Wilk test and quantile–quantile plot.Their statistical characteristics provided can be introduced to later related researches.The parameterization design method B-spline and Bezier are adopted to create geometry models with manufacturing error based on leading-edge angle and leading-edge radius.The influence of real manufacturing error is quantified and analyzed by self-developed non-intrusive polynomial chaos and Sobol’indices.The mechanism of leading-edge manufacturing error on aerodynamic performance is discussed.The results show that the total pressure loss coefficient is sensitive to the leading-edge manufacturing error compared with the static pressure ratio,especially at high incidence.Specifically,manufacturing error of the leading edge will influence the local flow acceleration and subsequently cause fluctuation of the downstream flow.The aerodynamic performance is sensitive to the manufacturing error of leading-edge radius at the design and negative incidences,while it is sensitive to the manufacturing error of leading-edge angle under the operation conditions with high incidences.
基金supported by the National Natural Science Foundation of China (Nos.51236001,51006005)the National Basic Research Program of China (No. 2012CB720201)Beijing Natural Science Foundation (No. 3151002)
文摘The circumferentially averaged equation of the inlet flow radial equilibrium in axial compressor was deduced. It indicates that the blade inlet radial pressure gradient is closely related to the radial component of the circumferential fluctuation（CF） source item. Several simplified cascades with/without aerodynamic loading were numerically studied to investigate the effects of blade bowing on the inlet flow radial equilibrium. A data reduction program was conducted to obtain the CF source from three-dimensional（3D） simulation results. Flow parameters at the passage inlet were focused on and each term in the radial equilibrium equation was discussed quantitatively. Results indicate that the inviscid blade force is the inducement of the inlet CF due to geometrical asymmetry. Blade bowing induces variation of the inlet CF, thus changes the radial pressure gradient and leads to flow migration before leading edge（LE） in the cascades. Positive bowing drives the inlet flow to migrate from end walls to mid-span and negative bowing turns it to the reverse direction to build a new equilibrium. In addition, comparative studies indicate that the inlet Mach number and blade loading can efficiently impact the effectiveness of blade bowing on radial equilibrium in compressor design.
基金supported by National Basic Research Program of China (Grant No 2006CB705500)Changjiang Scholars and Innovative Research Team in University (Grant No IRT0605)the National Natural Science Foundation of China (Grant No 70631001)
文摘In this paper, cascading failure is studied by coupled map lattice （CML） methods in preferential attachment community networks. It is found that external perturbation R is increasing with modularity Q growing by simulation. In particular, the large modularity Q can hold off the cascading failure dynamic process in community networks. Furthermore, different attack strategies also greatly affect the cascading failure dynamic process. It is particularly significant to control cascading failure process in real community networks.
