Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale pr...Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale proposed in this work are used to simulate the thermal conductivity behaviors of the 3D C/SiC composites.An entirely new process is introduced to weave the preform with three-dimensional orthogonal architecture.The 3D steady-state analysis step is created for assessing the thermal conductivity behaviors of the composites by applying periodic temperature boundary conditions.Three RVE models of cuboid,hexagonal and fiber random distribution are respectively developed to comparatively study the influence of fiber package pattern on the thermal conductivities at the microscale.Besides,the effect of void morphology on the thermal conductivity of the matrix is analyzed by the void/matrix models.The prediction results at the mesoscale correspond closely to the experimental values.The effect of the porosities and fiber volume fractions on the thermal conductivities is also taken into consideration.The multi-scale models mentioned in this paper can be used to predict the thermal conductivity behaviors of other composites with complex structures.展开更多
Lithium-sulfur battery(LSB)has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems.The widely comme...Lithium-sulfur battery(LSB)has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems.The widely commercial application and development of LSB is mainly hindered by serious“shuttle effect”of lithium polysulfides(Li PSs),slow reaction kinetics,notorious lithium dendrites,etc.In various structures of LSB materials,array structured materials,possessing the composition of ordered micro units with the same or similar characteristics of each unit,present excellent application potential for various secondary cells due to some merits such as immobilization of active substances,high specific surface area,appropriate pore sizes,easy modification of functional material surface,accommodated huge volume change,enough facilitated transportation for electrons/lithium ions,and special functional groups strongly adsorbing Li PSs.Thus many novel array structured materials are applied to battery for tackling thorny problems mentioned above.In this review,recent progresses and developments on array structured materials applied in LSBs including preparation ways,collaborative structural designs based on array structures,and action mechanism analyses in improving electrochemical performance and safety are summarized.Meanwhile,we also have detailed discussion for array structured materials in LSBs and constructed the structure-function relationships between array structured materials and battery performances.Lastly,some directions and prospects about preparation ways,functional modifications,and practical applications of array structured materials in LSBs are generalized.We hope the review can attract more researchers'attention and bring more studying on array structured materials for other secondary batteries including LSB.展开更多
Purpose: The aim of this article is to explore up to seven parameters related to the methodological quality and reproducibility of thematic bibliometric research published in the two most productive journals in biblio...Purpose: The aim of this article is to explore up to seven parameters related to the methodological quality and reproducibility of thematic bibliometric research published in the two most productive journals in bibliometrics, Sustainability(a journal outside the discipline) and Scientometrics, the flagship journal in the field.Design/methodology/approach: The study identifies the need for developing tailored tools for improving the quality of thematic bibliometric analyses, and presents a framework that can guide the development of such tools. A total of 508 papers are analysed, 77% of Sustainability, and 23% published in Scientometrics, for the 2019-2021 period.Findings: An average of 2.6 shortcomings per paper was found for the whole sample, with an almost identical number of flaws in both journals. Sustainability has more flaws than Scientometrics in four of the seven parameters studied, while Scientometrics has more shortcomings in the remaining three variables.Research limitations: The first limitation of this work is that it is a study of two scientific journals, so the results cannot be directly extrapolated to the set of thematic bibliometric analyses published in journals from all fields.Practical implications: We propose the adoption of protocols, guidelines, and other similar tools, adapted to bibliometric practice, which could increase the thoroughness, transparency, and reproducibility of this type of research.Originality/value: These results show considerable room for improvement in terms of the adequate use and breakdown of methodological procedures in thematic bibliometric research, both in journals in the Information Science area and journals outside the discipline.展开更多
In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented.The kinematic relations are developed based on higherorder sinusoi...In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented.The kinematic relations are developed based on higherorder sinusoidal shear deformation theory.Thickness stretching formulation is accounted for more accurate analysis.The total transverse deflection is divided into bending,shear and thickness stretching parts in which the third term is responsible for change of deflection along the thickness direction.The axisymmetric formulations are derived through principle of virtual work.A parametric study is presented to investigate variation of stress and strain components along the thickness and longitudinal directions.To explore effect of thickness stretching model on the static results,a comparison between the present results with the available results of literature is presented.As an important output,effect of micro-scale parameter is studied on the static stress and strain distribution.展开更多
Though prior research has identified that gratitude is associated with benign/malicious envy(BeMaS).The pur-pose of this study was to explore the causal relationship between gratitude and BeMaS among Chinese adoles-cen...Though prior research has identified that gratitude is associated with benign/malicious envy(BeMaS).The pur-pose of this study was to explore the causal relationship between gratitude and BeMaS among Chinese adoles-cents.The two-wave study,in which 906 adolescents participated,includes measurements of gratitude and BeMaS.We employed the structural equation models to test the cross-lagged effect between trait gratitude and BeMaS.The results showed that gratitude could positively predict benign envy and could negatively predict mal-icious envy.Besides,there was no evidence for the reverse or reciprocal relationships between gratitude and BeMaS.Thefindings provide further evidence about the causal relationship between gratitude and BeMaS among adolescents.Moreover,these results have implications for gratitude interventions that promote the constructive meaning of envy and reduce the negative influence of envy.展开更多
BACKGROUND Colonization with Helicobacter pylori(H.pylori)has a strong correlation with gastric cancer,and the virulence factor CagA is implicated in carcinogenesis.Studies have been conducted using medicinal plants w...BACKGROUND Colonization with Helicobacter pylori(H.pylori)has a strong correlation with gastric cancer,and the virulence factor CagA is implicated in carcinogenesis.Studies have been conducted using medicinal plants with the aim of eliminating the pathogen;however,the possibility of blocking H.pylori-induced cell differentiation to prevent the onset and/or progression of tumors has not been addressed.This type of study is expensive and time-consuming,requiring in vitro and/or in vivo tests,which can be solved using bioinformatics.Therefore,prospective computational analyses were conducted to assess the feasibility of interaction between phenolic compounds from medicinal plants and the CagA oncoprotein.AIM To perform a computational prospecting of the interactions between phenolic compounds from medicinal plants and the CagA oncoprotein of H.pylori.METHODS In this in silico study,the structures of the phenolic compounds(ligands)kaempferol,myricetin,quercetin,ponciretin(flavonoids),and chlorogenic acid(phenolic acid)were selected from the PubChem database.These phenolic compounds were chosen based on previous studies that suggested medicinal plants as non-drug treatments to eliminate H.pylori infection.The three-dimensional structure model of the CagA oncoprotein of H.pylori(receptor)was obtained through molecular modeling using computational tools from the I-Tasser platform,employing the threading methodology.The primary sequence of CagA was sourced from GenBank(BAK52797.1).A screening was conducted to identify binding sites in the structure of the CagA oncoprotein that could potentially interact with the ligands,utilizing the GRaSP online platform.Both the ligands and receptor were prepared for molecular docking using AutoDock Tools 4(ADT)software,and the simulations were carried out using a combination of ADT and AutoDock Vina v.1.2.0 software.Two sets of simulations were performed:One involving the central region of CagA with phenolic compounds,and another involving the carboxy-terminus region of CagA with phenolic compounds.The receptor-ligand complexes were then analyzed using PyMol and BIOVIA Discovery Studio software.RESULTS The structure model obtained for the CagA oncoprotein exhibited high quality(C-score=0.09)and was validated using parameters from the MolProbity platform.The GRaSP online platform identified 24 residues(phenylalanine and leucine)as potential binding sites on the CagA oncoprotein.Molecular docking simulations were conducted with the three-dimensional model of the CagA oncoprotein.No complexes were observed in the simulations between the carboxy-terminus region of CagA and the phenolic compounds;however,all phenolic compounds interacted with the central region of the oncoprotein.Phenolic compounds and CagA exhibited significant affinity energy(-7.9 to-9.1 kcal/mol):CagA/kaempferol formed 28 chemical bonds,CagA/myricetin formed 18 chemical bonds,CagA/quercetin formed 16 chemical bonds,CagA/ponciretin formed 13 chemical bonds,and CagA/chlorogenic acid formed 17 chemical bonds.Although none of the phenolic compounds directly bound to the amino acid residues of the K-Xn-R-X-R membrane binding motif,all of them bound to residues,mostly positively or negatively charged,located near this region.CONCLUSION In silico,the tested phenolic compounds formed stable complexes with CagA.Therefore,they could be tested in vitro and/or in vivo to validate the findings,and to assess interference in CagA/cellular target interactions and in the oncogenic differentiation of gastric cells.展开更多
This paper deals with the validation and theoretical analyses of a simple method for calculating the intrinsic rate of increase, rm, of aphids and mites. This method does not require a detailed fecundity table data. T...This paper deals with the validation and theoretical analyses of a simple method for calculating the intrinsic rate of increase, rm, of aphids and mites. This method does not require a detailed fecundity table data. The value of rm can be estimated by the simple equation: rm=0.74ln (Md)/d, where d is the time from birth to first reproduction; Md is the number of female offspring produced per original female in 2d. This method was developed by Wyatt and White. We reached the following conclusions from our study: When the parameter, Md is less than 1, this equation is not appropriate for estimating rm of populations; When the parameter, Md is larger than 1 and about 70% or more of the reproductive contribution to the rm is achieved in 2d, the equation is appropriate for calculatng the rm of aphids and mites.As Md decreases, the required reproductive contribution to the rm in 2d corresponding to the constant 0.74 will increase. However, whether 70% or more of reproductive contribution to rm is achieved in 2d still is a problem for whole taxa of aphids and mites. Therefore, further siudy on reproductive distribution will be required for practical application of this method.展开更多
Although tourism marketing has made great progress in recent years,researches on it are far from enough.Current re searches on tourism marketing at home and abroad lack pertinence and mostly provide theoretical basis ...Although tourism marketing has made great progress in recent years,researches on it are far from enough.Current re searches on tourism marketing at home and abroad lack pertinence and mostly provide theoretical basis for tourism development within a wide range.The researches on tourism marketing of Penglai are few and far between.Based on previous studies and the status quo of tourism marketing strategy,the below statements tries to find out existing problems of Penglai's tourism,put for ward countermeasures and propose feasible marketing patterns suitable for its tourism development.It subsequently concludes that it can make contribution to the sustainable development of Penglai's tourism and provide other county-level tourism cities with reference for marketing tourism marketing strategies.展开更多
In this paper, we try to use the entransy theory to analyze the heat–work conversion systems with inner irreversible thermodynamic cycles. First, the inner irreversible thermodynamic cycles are analyzed. The influenc...In this paper, we try to use the entransy theory to analyze the heat–work conversion systems with inner irreversible thermodynamic cycles. First, the inner irreversible thermodynamic cycles are analyzed. The influences of different inner irreversible factors on entransy loss are discussed. We find that the concept of entransy loss can be used to analyze the inner irreversible thermodynamic cycles. Then, we analyze the common heat–work conversion systems with inner irreversible thermodynamic cycles. As an example, the heat–work conversion system in which the working fluid of the thermodynamic cycles is heated and cooled by streams is analyzed. Our analyses show that larger entransy loss leads to larger output work when the total heat flow from the high temperature heat source and the corresponding equivalent temperature are fixed.Some numerical cases are presented, and the results verify the theoretical analyses. On the other hand, it is also found that larger entransy loss does not always lead to larger output work when the preconditions are not satisfied.展开更多
Heat exchangers are widely used in industry, and analyses and optimizations of the performance of heat exchangers are important topics. In this paper, we define the concept of entropy resistance based on the entropy g...Heat exchangers are widely used in industry, and analyses and optimizations of the performance of heat exchangers are important topics. In this paper, we define the concept of entropy resistance based on the entropy generation analyses of a one-dimensional heat transfer process. With this concept, a two-stream parallel flow heat exchanger with viscous heating is analyzed and discussed. It is found that the minimization of entropy resistance always leads to the maximum heat transfer rate for the discussed two-stream parallel flow heat exchanger, while the minimizations of entropy generation rate, entropy generation numbers, and revised entropy generation number do not always.展开更多
The water cooled ceramic breeder(WCCB) blanket employing pressurized water as a coolant is one of the breeding blanket candidates for the China Fusion Engineering Test Reactor(CFETR).Some updating of neutronics an...The water cooled ceramic breeder(WCCB) blanket employing pressurized water as a coolant is one of the breeding blanket candidates for the China Fusion Engineering Test Reactor(CFETR).Some updating of neutronics analyses was needed, because there were changes in the neutronics performance of the blanket as several significant modifications and improvements have been adopted for the WCCB blanket, including the optimization of radial build-up and customized structure for each blanket module. A 22.5 degree toroidal symmetrical torus sector 3 D neutronics model containing the updated design of the WCCB blanket modules was developed for the neutronics analyses. The tritium breeding capability, nuclear heating power, radiation damage,and decay heat were calculated by the MCNP and FISPACT code. The results show that the packing factor and^6 Li enrichment of the breeder should both be no less than 0.8 to ensure tritium self-sufficiency. The nuclear heating power of the blanket under 200 MW fusion power reaches201.23 MW. The displacement per atom per full power year(FPY) of the plasma-facing component and first wall reach 0.90 and 2.60, respectively. The peak H production rate reaches150.79 appm/FPY and the peak He production reaches 29.09 appm/FPY in blanket module #3.The total decay heat of the blanket modules is 2.64 MW at 1 s after shutdown and the average decay heat density can reach 11.09 kW m^(-3) at that time. The decay heat density of the blanket modules slowly decreases to lower than 10 W m^(-3) in more than ten years.展开更多
Kanas is a National Nature Reserve and National 5A Scenic Area,and it is also high on China’s National Natural Heritage List. In this paper,with an integrated analysis and comparative geo-graphical approach,the genes...Kanas is a National Nature Reserve and National 5A Scenic Area,and it is also high on China’s National Natural Heritage List. In this paper,with an integrated analysis and comparative geo-graphical approach,the genesis and current features of the Kanas landscape are analyzed systematically according to the criteria for outstanding universal values that must be met for designation by the United Nations as World Natural Heritage. It is concluded that Kanas has outstanding universal values in geosciences,biology and aesthetics. Through comparison with other World Natural Heritage sites of the same geological types,in the same biogeographic zone and in the same latitude,it is concluded that Kanas meets criteria vii,viii,ix and x for designation as World Natural Heritage. Thus,this work establishes a scientific foundation for nomination of Kanas for such a status.展开更多
Crack propagation processes in specially prepared concrete discs and rectangular specimens containing a single cylindrical hole or multiple holes of varying diameters have been studied both experimentally and numerica...Crack propagation processes in specially prepared concrete discs and rectangular specimens containing a single cylindrical hole or multiple holes of varying diameters have been studied both experimentally and numerically. In this research, the cracks coalescence paths in Brazilian disc and rectangular specimens made from rock-like material containing multi-holes are investigated. These concrete specimens are specially prepared from an appropriate mixture of Portland Pozzolana Cement (PPC), fine sands, and water. The pre-holed Brazilian discs and rectangular specimens are experimentally tested under compression. The breakage load in the ring type disc specimens containing an axial hole with varying diameters is measured and the distribution of the induced lateral stress is obtained. The mechanism of cracks propagation in the wall of the ring type specimens is also stud- ied. In the case of multi-hole Brazilian disc and rectangular specimens, the cracks propagation and cracks coalescence are also investigated. These experiments are numerically modeled by a modified higher order displacement discontinuity method. It has been shown that the corresponding experimental and numerical results are in good agreement with each other. The results presented in this research vali date the accuracy and applicability of these crack analyses procedures.展开更多
Oral squamous cell carcinoma(OSCC) is the most prevalent and most commonly studied oral cancer. However, there is a void regarding the role that the oral microbiome may play in OSCC. Although the relationship between ...Oral squamous cell carcinoma(OSCC) is the most prevalent and most commonly studied oral cancer. However, there is a void regarding the role that the oral microbiome may play in OSCC. Although the relationship between microbial community composition and OSCC has been thoroughly investigated, microbial profiles of the human microbiome in cancer are understudied. Here we performed a small pilot study of community-wide metatranscriptome analysis to profile mRNA expression in the entire oral microbiome in OSCC to reveal molecular functions associated with this disease. Fusobacteria showed a statistically significantly higher number of transcripts at tumour sites and tumour-adjacent sites of cancer patients compared to the healthy controls analysed. Regardless of the community composition, specific metabolic signatures were consistently found in disease. Activities such as iron ion transport, tryptophanase activity, peptidase activities and superoxide dismutase were over-represented in tumour and tumour-adjacent samples when compared to the healthy controls. The expression of putative virulence factors in the oral communities associated with OSCC showed that activities related to capsule biosynthesis, flagellum synthesis and assembly, chemotaxis, iron transport, haemolysins and adhesins were upregulated at tumour sites. Moreover, activities associated with protection against reactive nitrogen intermediates, chemotaxis, flagellar and capsule biosynthesis were also upregulated in non-tumour sites of cancer patients. Although they are preliminary, our results further suggest that Fusobacteria may be the leading phylogenetic group responsible for the increase in expression of virulence factors in the oral microbiome of OSCC patients.展开更多
In this paper,based on the generalized heat transfer law,an air conditioning system is analyzed with the entropy generation minimization and the entransy theory.Taking the coefficient of performance(denoted as COP) ...In this paper,based on the generalized heat transfer law,an air conditioning system is analyzed with the entropy generation minimization and the entransy theory.Taking the coefficient of performance(denoted as COP) and heat flow rate Qout which is released into the room as the optimization objectives,we discuss the applicabilities of the entropy generation minimization and entransy theory to the optimizations.Five numerical cases are presented.Combining the numerical results and theoretical analyses,we can conclude that the optimization applicabilities of the two theories are conditional.If Qout is the optimization objective,larger entransy increase rate always leads to larger Qout,while smaller entropy generation rate does not.If we take COP as the optimization objective,neither the entropy generation minimization nor the concept of entransy increase is always applicable.Furthermore,we find that the concept of entransy dissipation is not applicable for the discussed cases.展开更多
In this paper, novel mathematical expressions are derived for the Global Positioning System (GPS) receiver interference tolerance in the presence of different types of interference signals such as: continuous wave int...In this paper, novel mathematical expressions are derived for the Global Positioning System (GPS) receiver interference tolerance in the presence of different types of interference signals such as: continuous wave interference, narrowband interference, partial band interference, broadband interference, match spectrum interference and pulse interference. Also, in this paper the mean time to loss lock is determined in order to analyse the mentioned interferences effect on the GPS receiver. These derived analytical expressions are validated with the aid of extensive simulation experiments.展开更多
Ultrasonic welding is an effective ways to achieve a non-reactive/immiscible heterogeneous metal connection, such as the connection of magnesium alloy and titanium alloy. But the thermal mechanism of magnesium alloy/t...Ultrasonic welding is an effective ways to achieve a non-reactive/immiscible heterogeneous metal connection, such as the connection of magnesium alloy and titanium alloy. But the thermal mechanism of magnesium alloy/titanium alloy ultrasonic welding has not been defined clearly. In this paper, the experimental and the finite element analysis were adopted to study the thermal mechanism during welding. Through the test, the temperature variation law during the welding process is obtained, and the accuracy of the finite element model is verified. The microscopic analysis indicates that at the welding time of 0.5 s, the magnesium alloy in the center of the solder joint is partially melted and generates the liquid phase. Through the finite element analysis, the friction coefficient of the magnesium–titanium ultrasonic welding interface can be considered as an average constant value of 0.28. The maximum temperature at the interface can exceed 600 ℃ to reach the melting point temperature of the magnesium alloy. The plastic deformation begins after 0.35 s and occurs at the magnesium side at the center of the interface.展开更多
Aluminum ablation by multiple femtosecond laser pulses is investigated via time-resolved shadowgraphs and scanning electron microscope (SEM) images of the ablation spot. The spatial distribution of the ejected mater...Aluminum ablation by multiple femtosecond laser pulses is investigated via time-resolved shadowgraphs and scanning electron microscope (SEM) images of the ablation spot. The spatial distribution of the ejected material and the radius of the shock wave generated during the ablation are found to vary with the increase in the number of pulses. In the initial two pulses, nearly concentric and semicircular stripes within the shock wave front are observed, unlike in subsequent pulses. Ablation by multiple femtosecond pulses exhibits different characteristics compared with the case induced by single femtosecond pulse because of the changes to the aluminum target surface induced by the preceding pulses.展开更多
A series of scaled-model shaking table tests and its simulation analyses using dynamic finite element method were performed to clarify the dynamic behaviors and the seismic stability of embedded corrugated steel culve...A series of scaled-model shaking table tests and its simulation analyses using dynamic finite element method were performed to clarify the dynamic behaviors and the seismic stability of embedded corrugated steel culverts due to strong earth-quakes like the 1995 Hyogoken-nanbu earthquake. The dynamic strains of the embedded culvert models and the seismic soil pressure acting on the models due to sinusoidal and random strong motions were investigated. This study verified that the cor-rugated culvert model was subjected to dynamic horizontal forces (lateral seismic soil pressure) from the surrounding ground, which caused the large bending strains on the structure; and that the structures do not exceed the allowable plastic deformation and do not collapse completely during strong earthquake like Hyogoken-nanbu earthquake. The results obtained are useful for design and construction of embedded long span corrugated steel culverts in seismic regions.展开更多
Zokors in the genus Eospalax,which are endemic to northern and western China,are subterranean rodents that inhabit various niches,including grasslands,high-altitude meadows,forests,and farmlands.Six species in Eospala...Zokors in the genus Eospalax,which are endemic to northern and western China,are subterranean rodents that inhabit various niches,including grasslands,high-altitude meadows,forests,and farmlands.Six species in Eospalax were described a century ago but their taxonomy and phylogeny remain controversial.In this study,we performed high-depth whole-genome sequencing of 47 zokor samples,comprising all six previously described species.Genomic analyses revealed a reliable and robust phylogeny of Eospalax and supported the validity of the six named species.According to the inferred phylogenetic relationships,Eospalax first divergent into two clades in the early Pliocene(ca.4.68 million years ago(Ma)),one inhabiting the highaltitude Qinghai-Xizang(Tibet)Plateau(QTP)and adjacent regions,and the another inhabiting the lowaltitude Loess Plateau and Qinling-Daba Mountains.The most recent divergences occurred between E.baileyi and E.smithii and between E.rufescens and E.rothschildi in the late Pliocene(ca.2.09 and 2.19 Ma,respectively).We also collected specimens of zokors in the southern Hengduan Mountains(Muli County,Sichuan Province),far from the known distributions of all other zokors.Morphological and molecular analyses strongly suggested that the specimens represent a new species,formally described here as Eospalax muliensis sp.nov.The new species belongs to the high-altitude clade and diverged from closely related species(ca.4.22 Ma)shortly after the first divergence in Eospalax.Interestingly,Eospalax muliensis sp.nov.possesses more supposedly plesiomorphic characters,suggesting a possible origin of the genus in the Hengduan Mountains.展开更多
基金Supported by Science Center for Gas Turbine Project of China (Grant No.P2022-B-IV-014-001)Frontier Leading Technology Basic Research Special Project of Jiangsu Province of China (Grant No.BK20212007)the BIT Research and Innovation Promoting Project of China (Grant No.2022YCXZ019)。
文摘Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale proposed in this work are used to simulate the thermal conductivity behaviors of the 3D C/SiC composites.An entirely new process is introduced to weave the preform with three-dimensional orthogonal architecture.The 3D steady-state analysis step is created for assessing the thermal conductivity behaviors of the composites by applying periodic temperature boundary conditions.Three RVE models of cuboid,hexagonal and fiber random distribution are respectively developed to comparatively study the influence of fiber package pattern on the thermal conductivities at the microscale.Besides,the effect of void morphology on the thermal conductivity of the matrix is analyzed by the void/matrix models.The prediction results at the mesoscale correspond closely to the experimental values.The effect of the porosities and fiber volume fractions on the thermal conductivities is also taken into consideration.The multi-scale models mentioned in this paper can be used to predict the thermal conductivity behaviors of other composites with complex structures.
基金This work was supported by the National Natural Science Foundation of China(52203066,51973157,61904123)the Tianjin Natural Science Foundation(18JCQNJC02900)+3 种基金the National innovation and entrepreneurship training program for college students(202310058007)the Tianjin Municipal college students’innovation and entrepreneurship training program(202310058088)the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(Grant No.2018KJ196)the State Key Laboratory of Membrane and Membrane Separation,Tiangong University.
文摘Lithium-sulfur battery(LSB)has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems.The widely commercial application and development of LSB is mainly hindered by serious“shuttle effect”of lithium polysulfides(Li PSs),slow reaction kinetics,notorious lithium dendrites,etc.In various structures of LSB materials,array structured materials,possessing the composition of ordered micro units with the same or similar characteristics of each unit,present excellent application potential for various secondary cells due to some merits such as immobilization of active substances,high specific surface area,appropriate pore sizes,easy modification of functional material surface,accommodated huge volume change,enough facilitated transportation for electrons/lithium ions,and special functional groups strongly adsorbing Li PSs.Thus many novel array structured materials are applied to battery for tackling thorny problems mentioned above.In this review,recent progresses and developments on array structured materials applied in LSBs including preparation ways,collaborative structural designs based on array structures,and action mechanism analyses in improving electrochemical performance and safety are summarized.Meanwhile,we also have detailed discussion for array structured materials in LSBs and constructed the structure-function relationships between array structured materials and battery performances.Lastly,some directions and prospects about preparation ways,functional modifications,and practical applications of array structured materials in LSBs are generalized.We hope the review can attract more researchers'attention and bring more studying on array structured materials for other secondary batteries including LSB.
文摘Purpose: The aim of this article is to explore up to seven parameters related to the methodological quality and reproducibility of thematic bibliometric research published in the two most productive journals in bibliometrics, Sustainability(a journal outside the discipline) and Scientometrics, the flagship journal in the field.Design/methodology/approach: The study identifies the need for developing tailored tools for improving the quality of thematic bibliometric analyses, and presents a framework that can guide the development of such tools. A total of 508 papers are analysed, 77% of Sustainability, and 23% published in Scientometrics, for the 2019-2021 period.Findings: An average of 2.6 shortcomings per paper was found for the whole sample, with an almost identical number of flaws in both journals. Sustainability has more flaws than Scientometrics in four of the seven parameters studied, while Scientometrics has more shortcomings in the remaining three variables.Research limitations: The first limitation of this work is that it is a study of two scientific journals, so the results cannot be directly extrapolated to the set of thematic bibliometric analyses published in journals from all fields.Practical implications: We propose the adoption of protocols, guidelines, and other similar tools, adapted to bibliometric practice, which could increase the thoroughness, transparency, and reproducibility of this type of research.Originality/value: These results show considerable room for improvement in terms of the adequate use and breakdown of methodological procedures in thematic bibliometric research, both in journals in the Information Science area and journals outside the discipline.
文摘In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented.The kinematic relations are developed based on higherorder sinusoidal shear deformation theory.Thickness stretching formulation is accounted for more accurate analysis.The total transverse deflection is divided into bending,shear and thickness stretching parts in which the third term is responsible for change of deflection along the thickness direction.The axisymmetric formulations are derived through principle of virtual work.A parametric study is presented to investigate variation of stress and strain components along the thickness and longitudinal directions.To explore effect of thickness stretching model on the static results,a comparison between the present results with the available results of literature is presented.As an important output,effect of micro-scale parameter is studied on the static stress and strain distribution.
基金supported by Department of Education Project of Hunan Province of China(Grant No.2019291174).
文摘Though prior research has identified that gratitude is associated with benign/malicious envy(BeMaS).The pur-pose of this study was to explore the causal relationship between gratitude and BeMaS among Chinese adoles-cents.The two-wave study,in which 906 adolescents participated,includes measurements of gratitude and BeMaS.We employed the structural equation models to test the cross-lagged effect between trait gratitude and BeMaS.The results showed that gratitude could positively predict benign envy and could negatively predict mal-icious envy.Besides,there was no evidence for the reverse or reciprocal relationships between gratitude and BeMaS.Thefindings provide further evidence about the causal relationship between gratitude and BeMaS among adolescents.Moreover,these results have implications for gratitude interventions that promote the constructive meaning of envy and reduce the negative influence of envy.
文摘BACKGROUND Colonization with Helicobacter pylori(H.pylori)has a strong correlation with gastric cancer,and the virulence factor CagA is implicated in carcinogenesis.Studies have been conducted using medicinal plants with the aim of eliminating the pathogen;however,the possibility of blocking H.pylori-induced cell differentiation to prevent the onset and/or progression of tumors has not been addressed.This type of study is expensive and time-consuming,requiring in vitro and/or in vivo tests,which can be solved using bioinformatics.Therefore,prospective computational analyses were conducted to assess the feasibility of interaction between phenolic compounds from medicinal plants and the CagA oncoprotein.AIM To perform a computational prospecting of the interactions between phenolic compounds from medicinal plants and the CagA oncoprotein of H.pylori.METHODS In this in silico study,the structures of the phenolic compounds(ligands)kaempferol,myricetin,quercetin,ponciretin(flavonoids),and chlorogenic acid(phenolic acid)were selected from the PubChem database.These phenolic compounds were chosen based on previous studies that suggested medicinal plants as non-drug treatments to eliminate H.pylori infection.The three-dimensional structure model of the CagA oncoprotein of H.pylori(receptor)was obtained through molecular modeling using computational tools from the I-Tasser platform,employing the threading methodology.The primary sequence of CagA was sourced from GenBank(BAK52797.1).A screening was conducted to identify binding sites in the structure of the CagA oncoprotein that could potentially interact with the ligands,utilizing the GRaSP online platform.Both the ligands and receptor were prepared for molecular docking using AutoDock Tools 4(ADT)software,and the simulations were carried out using a combination of ADT and AutoDock Vina v.1.2.0 software.Two sets of simulations were performed:One involving the central region of CagA with phenolic compounds,and another involving the carboxy-terminus region of CagA with phenolic compounds.The receptor-ligand complexes were then analyzed using PyMol and BIOVIA Discovery Studio software.RESULTS The structure model obtained for the CagA oncoprotein exhibited high quality(C-score=0.09)and was validated using parameters from the MolProbity platform.The GRaSP online platform identified 24 residues(phenylalanine and leucine)as potential binding sites on the CagA oncoprotein.Molecular docking simulations were conducted with the three-dimensional model of the CagA oncoprotein.No complexes were observed in the simulations between the carboxy-terminus region of CagA and the phenolic compounds;however,all phenolic compounds interacted with the central region of the oncoprotein.Phenolic compounds and CagA exhibited significant affinity energy(-7.9 to-9.1 kcal/mol):CagA/kaempferol formed 28 chemical bonds,CagA/myricetin formed 18 chemical bonds,CagA/quercetin formed 16 chemical bonds,CagA/ponciretin formed 13 chemical bonds,and CagA/chlorogenic acid formed 17 chemical bonds.Although none of the phenolic compounds directly bound to the amino acid residues of the K-Xn-R-X-R membrane binding motif,all of them bound to residues,mostly positively or negatively charged,located near this region.CONCLUSION In silico,the tested phenolic compounds formed stable complexes with CagA.Therefore,they could be tested in vitro and/or in vivo to validate the findings,and to assess interference in CagA/cellular target interactions and in the oncogenic differentiation of gastric cells.
文摘This paper deals with the validation and theoretical analyses of a simple method for calculating the intrinsic rate of increase, rm, of aphids and mites. This method does not require a detailed fecundity table data. The value of rm can be estimated by the simple equation: rm=0.74ln (Md)/d, where d is the time from birth to first reproduction; Md is the number of female offspring produced per original female in 2d. This method was developed by Wyatt and White. We reached the following conclusions from our study: When the parameter, Md is less than 1, this equation is not appropriate for estimating rm of populations; When the parameter, Md is larger than 1 and about 70% or more of the reproductive contribution to the rm is achieved in 2d, the equation is appropriate for calculatng the rm of aphids and mites.As Md decreases, the required reproductive contribution to the rm in 2d corresponding to the constant 0.74 will increase. However, whether 70% or more of reproductive contribution to rm is achieved in 2d still is a problem for whole taxa of aphids and mites. Therefore, further siudy on reproductive distribution will be required for practical application of this method.
文摘Although tourism marketing has made great progress in recent years,researches on it are far from enough.Current re searches on tourism marketing at home and abroad lack pertinence and mostly provide theoretical basis for tourism development within a wide range.The researches on tourism marketing of Penglai are few and far between.Based on previous studies and the status quo of tourism marketing strategy,the below statements tries to find out existing problems of Penglai's tourism,put for ward countermeasures and propose feasible marketing patterns suitable for its tourism development.It subsequently concludes that it can make contribution to the sustainable development of Penglai's tourism and provide other county-level tourism cities with reference for marketing tourism marketing strategies.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51376101 and 51356001)
文摘In this paper, we try to use the entransy theory to analyze the heat–work conversion systems with inner irreversible thermodynamic cycles. First, the inner irreversible thermodynamic cycles are analyzed. The influences of different inner irreversible factors on entransy loss are discussed. We find that the concept of entransy loss can be used to analyze the inner irreversible thermodynamic cycles. Then, we analyze the common heat–work conversion systems with inner irreversible thermodynamic cycles. As an example, the heat–work conversion system in which the working fluid of the thermodynamic cycles is heated and cooled by streams is analyzed. Our analyses show that larger entransy loss leads to larger output work when the total heat flow from the high temperature heat source and the corresponding equivalent temperature are fixed.Some numerical cases are presented, and the results verify the theoretical analyses. On the other hand, it is also found that larger entransy loss does not always lead to larger output work when the preconditions are not satisfied.
基金supported by the National Natural Science Foundation of China(Grant No.51106082)the Tsinghua University Initiative Scientific Research Program
文摘Heat exchangers are widely used in industry, and analyses and optimizations of the performance of heat exchangers are important topics. In this paper, we define the concept of entropy resistance based on the entropy generation analyses of a one-dimensional heat transfer process. With this concept, a two-stream parallel flow heat exchanger with viscous heating is analyzed and discussed. It is found that the minimization of entropy resistance always leads to the maximum heat transfer rate for the discussed two-stream parallel flow heat exchanger, while the minimizations of entropy generation rate, entropy generation numbers, and revised entropy generation number do not always.
基金supported by the National Special Project for Magnetic Confined Nuclear Fusion Energy(Grant Nos 2013GB108004,2014GB119000,and 2015BG108002)
文摘The water cooled ceramic breeder(WCCB) blanket employing pressurized water as a coolant is one of the breeding blanket candidates for the China Fusion Engineering Test Reactor(CFETR).Some updating of neutronics analyses was needed, because there were changes in the neutronics performance of the blanket as several significant modifications and improvements have been adopted for the WCCB blanket, including the optimization of radial build-up and customized structure for each blanket module. A 22.5 degree toroidal symmetrical torus sector 3 D neutronics model containing the updated design of the WCCB blanket modules was developed for the neutronics analyses. The tritium breeding capability, nuclear heating power, radiation damage,and decay heat were calculated by the MCNP and FISPACT code. The results show that the packing factor and^6 Li enrichment of the breeder should both be no less than 0.8 to ensure tritium self-sufficiency. The nuclear heating power of the blanket under 200 MW fusion power reaches201.23 MW. The displacement per atom per full power year(FPY) of the plasma-facing component and first wall reach 0.90 and 2.60, respectively. The peak H production rate reaches150.79 appm/FPY and the peak He production reaches 29.09 appm/FPY in blanket module #3.The total decay heat of the blanket modules is 2.64 MW at 1 s after shutdown and the average decay heat density can reach 11.09 kW m^(-3) at that time. The decay heat density of the blanket modules slowly decreases to lower than 10 W m^(-3) in more than ten years.
基金funded by the Project of Science and Tech-nology Plan of Xinjiang Uygur Autonomous Region (200933128)the National Natural Science Foundation of China (40671057)the Chinese Academy of Sciences Visiting Professorship for Senior International Scientists (2009S1-35)
文摘Kanas is a National Nature Reserve and National 5A Scenic Area,and it is also high on China’s National Natural Heritage List. In this paper,with an integrated analysis and comparative geo-graphical approach,the genesis and current features of the Kanas landscape are analyzed systematically according to the criteria for outstanding universal values that must be met for designation by the United Nations as World Natural Heritage. It is concluded that Kanas has outstanding universal values in geosciences,biology and aesthetics. Through comparison with other World Natural Heritage sites of the same geological types,in the same biogeographic zone and in the same latitude,it is concluded that Kanas meets criteria vii,viii,ix and x for designation as World Natural Heritage. Thus,this work establishes a scientific foundation for nomination of Kanas for such a status.
基金sponsored by Iran’s National Elites Foundation (INEF)
文摘Crack propagation processes in specially prepared concrete discs and rectangular specimens containing a single cylindrical hole or multiple holes of varying diameters have been studied both experimentally and numerically. In this research, the cracks coalescence paths in Brazilian disc and rectangular specimens made from rock-like material containing multi-holes are investigated. These concrete specimens are specially prepared from an appropriate mixture of Portland Pozzolana Cement (PPC), fine sands, and water. The pre-holed Brazilian discs and rectangular specimens are experimentally tested under compression. The breakage load in the ring type disc specimens containing an axial hole with varying diameters is measured and the distribution of the induced lateral stress is obtained. The mechanism of cracks propagation in the wall of the ring type specimens is also stud- ied. In the case of multi-hole Brazilian disc and rectangular specimens, the cracks propagation and cracks coalescence are also investigated. These experiments are numerically modeled by a modified higher order displacement discontinuity method. It has been shown that the corresponding experimental and numerical results are in good agreement with each other. The results presented in this research vali date the accuracy and applicability of these crack analyses procedures.
基金supported by the Evans Center for Interdisciplinary Biomedical Research ARC on ‘Oral microbiome in AhR activation and oral cancer development and progression’ at Boston University (http://www.bumc.bu.edu/evanscenteribr/)the Forsyth Institute pilot grant programme
文摘Oral squamous cell carcinoma(OSCC) is the most prevalent and most commonly studied oral cancer. However, there is a void regarding the role that the oral microbiome may play in OSCC. Although the relationship between microbial community composition and OSCC has been thoroughly investigated, microbial profiles of the human microbiome in cancer are understudied. Here we performed a small pilot study of community-wide metatranscriptome analysis to profile mRNA expression in the entire oral microbiome in OSCC to reveal molecular functions associated with this disease. Fusobacteria showed a statistically significantly higher number of transcripts at tumour sites and tumour-adjacent sites of cancer patients compared to the healthy controls analysed. Regardless of the community composition, specific metabolic signatures were consistently found in disease. Activities such as iron ion transport, tryptophanase activity, peptidase activities and superoxide dismutase were over-represented in tumour and tumour-adjacent samples when compared to the healthy controls. The expression of putative virulence factors in the oral communities associated with OSCC showed that activities related to capsule biosynthesis, flagellum synthesis and assembly, chemotaxis, iron transport, haemolysins and adhesins were upregulated at tumour sites. Moreover, activities associated with protection against reactive nitrogen intermediates, chemotaxis, flagellar and capsule biosynthesis were also upregulated in non-tumour sites of cancer patients. Although they are preliminary, our results further suggest that Fusobacteria may be the leading phylogenetic group responsible for the increase in expression of virulence factors in the oral microbiome of OSCC patients.
基金Project supported by the Youth Programs of Chongqing Three Gorges University,China(Grant No.13QN18)
文摘In this paper,based on the generalized heat transfer law,an air conditioning system is analyzed with the entropy generation minimization and the entransy theory.Taking the coefficient of performance(denoted as COP) and heat flow rate Qout which is released into the room as the optimization objectives,we discuss the applicabilities of the entropy generation minimization and entransy theory to the optimizations.Five numerical cases are presented.Combining the numerical results and theoretical analyses,we can conclude that the optimization applicabilities of the two theories are conditional.If Qout is the optimization objective,larger entransy increase rate always leads to larger Qout,while smaller entropy generation rate does not.If we take COP as the optimization objective,neither the entropy generation minimization nor the concept of entransy increase is always applicable.Furthermore,we find that the concept of entransy dissipation is not applicable for the discussed cases.
文摘In this paper, novel mathematical expressions are derived for the Global Positioning System (GPS) receiver interference tolerance in the presence of different types of interference signals such as: continuous wave interference, narrowband interference, partial band interference, broadband interference, match spectrum interference and pulse interference. Also, in this paper the mean time to loss lock is determined in order to analyse the mentioned interferences effect on the GPS receiver. These derived analytical expressions are validated with the aid of extensive simulation experiments.
基金Supported by National Natural Science Foundation of China(Grant Nos.U1764251,51775160)Fundamental Research Funds for the Central Universities of China(Grant No.DUT19LAB24)
文摘Ultrasonic welding is an effective ways to achieve a non-reactive/immiscible heterogeneous metal connection, such as the connection of magnesium alloy and titanium alloy. But the thermal mechanism of magnesium alloy/titanium alloy ultrasonic welding has not been defined clearly. In this paper, the experimental and the finite element analysis were adopted to study the thermal mechanism during welding. Through the test, the temperature variation law during the welding process is obtained, and the accuracy of the finite element model is verified. The microscopic analysis indicates that at the welding time of 0.5 s, the magnesium alloy in the center of the solder joint is partially melted and generates the liquid phase. Through the finite element analysis, the friction coefficient of the magnesium–titanium ultrasonic welding interface can be considered as an average constant value of 0.28. The maximum temperature at the interface can exceed 600 ℃ to reach the melting point temperature of the magnesium alloy. The plastic deformation begins after 0.35 s and occurs at the magnesium side at the center of the interface.
基金Project supported by the Science and Technology Development Fund Planning Project for the Universities of Tianjin,China(Grant No.20140902)the Natural Science Foundation of Tianjin City,China(Grant No.16JCQNJC01900)+1 种基金the National Natural Science Foundation of China(Grant Nos.51376136and 61474082)the Science and Technology Achievement Award Project for the Universities of Tianjin,China
文摘Aluminum ablation by multiple femtosecond laser pulses is investigated via time-resolved shadowgraphs and scanning electron microscope (SEM) images of the ablation spot. The spatial distribution of the ejected material and the radius of the shock wave generated during the ablation are found to vary with the increase in the number of pulses. In the initial two pulses, nearly concentric and semicircular stripes within the shock wave front are observed, unlike in subsequent pulses. Ablation by multiple femtosecond pulses exhibits different characteristics compared with the case induced by single femtosecond pulse because of the changes to the aluminum target surface induced by the preceding pulses.
文摘A series of scaled-model shaking table tests and its simulation analyses using dynamic finite element method were performed to clarify the dynamic behaviors and the seismic stability of embedded corrugated steel culverts due to strong earth-quakes like the 1995 Hyogoken-nanbu earthquake. The dynamic strains of the embedded culvert models and the seismic soil pressure acting on the models due to sinusoidal and random strong motions were investigated. This study verified that the cor-rugated culvert model was subjected to dynamic horizontal forces (lateral seismic soil pressure) from the surrounding ground, which caused the large bending strains on the structure; and that the structures do not exceed the allowable plastic deformation and do not collapse completely during strong earthquake like Hyogoken-nanbu earthquake. The results obtained are useful for design and construction of embedded long span corrugated steel culverts in seismic regions.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(2019QZKK05010218,2019QZKK05010110)National Natural Science Foundation of China(32100339,31871277)+2 种基金supported by the Yunling Scholar ProjectTen-Thousand Talents Plan of Yunnan Provincesupported by the Youth Innovation Promotion Association,Chinese Academy of Sciences。
文摘Zokors in the genus Eospalax,which are endemic to northern and western China,are subterranean rodents that inhabit various niches,including grasslands,high-altitude meadows,forests,and farmlands.Six species in Eospalax were described a century ago but their taxonomy and phylogeny remain controversial.In this study,we performed high-depth whole-genome sequencing of 47 zokor samples,comprising all six previously described species.Genomic analyses revealed a reliable and robust phylogeny of Eospalax and supported the validity of the six named species.According to the inferred phylogenetic relationships,Eospalax first divergent into two clades in the early Pliocene(ca.4.68 million years ago(Ma)),one inhabiting the highaltitude Qinghai-Xizang(Tibet)Plateau(QTP)and adjacent regions,and the another inhabiting the lowaltitude Loess Plateau and Qinling-Daba Mountains.The most recent divergences occurred between E.baileyi and E.smithii and between E.rufescens and E.rothschildi in the late Pliocene(ca.2.09 and 2.19 Ma,respectively).We also collected specimens of zokors in the southern Hengduan Mountains(Muli County,Sichuan Province),far from the known distributions of all other zokors.Morphological and molecular analyses strongly suggested that the specimens represent a new species,formally described here as Eospalax muliensis sp.nov.The new species belongs to the high-altitude clade and diverged from closely related species(ca.4.22 Ma)shortly after the first divergence in Eospalax.Interestingly,Eospalax muliensis sp.nov.possesses more supposedly plesiomorphic characters,suggesting a possible origin of the genus in the Hengduan Mountains.