This contribution presents a novel wear dependent virtual flow rate sensor for single stage single lobe progressing cavity pumps. We study the wear-induced material loss of the pump components and the impact of this m...This contribution presents a novel wear dependent virtual flow rate sensor for single stage single lobe progressing cavity pumps. We study the wear-induced material loss of the pump components and the impact of this material loss on the volumetric efficiency. The results are combined with an established backflow model to implement a backflow calculation procedure that is adaptive to wear. We use a laboratory test setup with a highly abrasive fluid and operate a pump from new to worn condition to validate our approach. The obtained measurement data show that the presented virtual sensor is capable of calculating the flow rate of a pump being subject to wear during its regular operation.展开更多
In 2021,the Belle collaboration reported the first observation of a new structure in theψ(2S)γfinal state produced in the two-photon fusion process.In the hadronic molecule picture,this new structure can be associat...In 2021,the Belle collaboration reported the first observation of a new structure in theψ(2S)γfinal state produced in the two-photon fusion process.In the hadronic molecule picture,this new structure can be associatedwith the shallow isoscalar D*D* bound state and as such is an excellent candidate for the spin-2 partner of the X(3872)with the quantum numbers J^(PC)=2^(++)conventionally named X_(2).展开更多
Building a covalently connected structure with accelerated photo-induced electrons and charge-carrier separation between semiconductors could enhance the photocatalytic performance.In this work,we report a facile and ...Building a covalently connected structure with accelerated photo-induced electrons and charge-carrier separation between semiconductors could enhance the photocatalytic performance.In this work,we report a facile and novel seed growth method to coat NH2-MIL-125 MOFs with crystalline and porous covalent organic frameworks(COFs)materials and form a range of NH2-MIL-125@TAPB-PDA nanocomposites with different thicknesses of COF shell.The introduction of appropriate content of COF could not only modify the intrinsic electronic and optical properties,but also enhance the photocatalytic activity distinctly.Especially,NH2-MIL-125@TAPB-PDA-3 with COF shell thickness of around 20nm exhibited the highest yield(94.7%)of benzaldehyde which is approximately 2.5 and 15.5 times as that of parental NH2-MIL-125 and COF,respectively.The promoted photocatalytic performance of hybrid materials was mainly owing to the enhanced photo-induced charge carriers transfer between the MOF and COF through the covalent bond.In addition,a possible mechanism to elucidate the process of photocatalysis was explored.Therefore,this kind of MOF-based photocatalysts possesses great potentials in future green organic synthesis.展开更多
Ni-Ti-based shape memory alloys(SMAs)have found widespread use in the last 70 years,but improving their functional stability remains a key quest for more robust and advanced applications.Named for their ability to ret...Ni-Ti-based shape memory alloys(SMAs)have found widespread use in the last 70 years,but improving their functional stability remains a key quest for more robust and advanced applications.Named for their ability to retain their processed shape as a result of a reversible martensitic transformation,SMAs are highly sensitive to compositional variations.Alloying with ternary and quaternary elements to finetune the lattice parameters and the thermal hysteresis of an SMA,therefore,becomes a challenge in materials exploration.Combinatorial materials science allows streamlining of the synthesis process and data management from multiple characterization techniques.In this study,a composition spread of Ni-Ti-Cu-V thin-film library was synthesized by magnetron co-sputtering on a thermally oxidized Si wafer.Composition-dependent phase transformation temperature and microstructure were investigated and determined using high-throughput wavelength dispersive spectroscopy,synchrotron X-ray diffraction,and temperature-dependent resistance measurements.Of the 177 compositions in the materials library,32 were observed to have shape memory effect,of which five had zero or near-zero thermal hysteresis.These compositions provide flexibility in the operating temperature regimes that they can be used in.A phase map for the quaternary system and correlations of functional properties are discussed w让h respect to the local microstructure and composition of the thin-film library.展开更多
16 Mg-Al-Zn-Bi quaternary alloys were utilized to measure the phase equilibria and transformation temperatures in the Mg-rich Mg-Al-Zn-Bi quaternary system by means of the X-ray diffraction,electron probe micro-analys...16 Mg-Al-Zn-Bi quaternary alloys were utilized to measure the phase equilibria and transformation temperatures in the Mg-rich Mg-Al-Zn-Bi quaternary system by means of the X-ray diffraction,electron probe micro-analysis and differential scanning calorimetry techniques.The isothermal section at 400℃and three vertical sections along Mg-8 wt%Al-0.75 wt%Zn-vBi,Mg-3.4 wt%Al-0.5 wt%Zn-ABi and Mg-6.9 wt%Al-2.3 wt%Zn-xBi in the Mg-Al-Zn-Bi quaternary system were constructed.Based on the literature data,the ternary Mg-Al-Bi and Mg-Bi-Zn systems were re-assessed using the CALculaiton of PHAse Diagram(CALPHAD)approach.The calculated phase equilibria agree well with the measured data.By directly extrapolating the constituent sub-ternary systems,the thermodynamic database for the Mg-Al-Zn-Bi quaternary system was developed.The remarkable consistency between the predicted phase equilibria and the presently measured data in Mg-Al-Zn-Bi quaternary system further demonstrated the accuracy and reliability of the established thermodynamic database.After that,by using the newly developed thermodynamic database,the growth restrict factors and the solidification curves in Bi-containing AZ series magnesium alloys were calculated and analyzed.It was confirmed that the grain size of AZ alloys can be refined with the addition of Bi,and the comp on ent Al had larger grain refinement effect than Bi.Besides,the amount of Bi had also no ticeable effect on the solidification sequence of the AZ alloys.展开更多
A relatively self-consistent theory of dust-acoustic waves in the strongly coupled dusty plasmas containing variable-charge impurities is given.Relevant physical processes such as dust elastic relaxation and dust char...A relatively self-consistent theory of dust-acoustic waves in the strongly coupled dusty plasmas containing variable-charge impurities is given.Relevant physical processes such as dust elastic relaxation and dust charge relaxation are taken into account.It is shown that the negative dispersion of dust-acoustic waves due to the strong correlation of dusts is enhanced in the presence of dust-neutral collisions.展开更多
Discovery of the remains of belemnites referred to the Hibolithes sp.from the Jurassic–Cretaceous Pedawan Formation in Sarawak,on the island of Borneo(Malaysia)comprises four fragments of belemnite rostra.The specime...Discovery of the remains of belemnites referred to the Hibolithes sp.from the Jurassic–Cretaceous Pedawan Formation in Sarawak,on the island of Borneo(Malaysia)comprises four fragments of belemnite rostra.The specimens are characterized by multiple fractures and vein filling.Two fragments measuring about 130 mm are relatively intact,with only part of the alveolar region missing;a third piece represents the middle part of a rostrum,and the fourth specimen is too fragmentary to be assigned to any specific part of the rostrum.Based on specimen characteristics,a Tithonian–Hauterivian age is plausible.The sedimentary succession that yielded the belemnite material comprises thick shale that reflects the Te division of Bouma sequence.The occurrence of a Hibolithes taxon in the uppermost Jurassic to lowermost Cretaceous Pedawan Formation sediments in Borneo reflects a near to global palaeobiogeographic distribution of this genus.展开更多
Recently,a relativistic chiral nucleon-nucleon interaction was formulated up to leading order,which provides a good description of the phase shifts of J≤1 partial waves[Chin.Phys.C 42(2018)014103].Nevertheless,a sepa...Recently,a relativistic chiral nucleon-nucleon interaction was formulated up to leading order,which provides a good description of the phase shifts of J≤1 partial waves[Chin.Phys.C 42(2018)014103].Nevertheless,a separable regulator function that is not manifestly covariant was used in solving the relativistic scattering equation.In the present work,we first explore a covariant and separable form factor to regularize the kernel potential and then apply it to study the simplest but most challenging ^(1)S_(0) channel which features several lowenergy scales.In addition to being self-consistent,we show that the resulting relativistic potential can describe quite well the unique features of the ^(1)S_(0) channel at leading order,in particular the pole position of the virtual bound state and the zero amplitude at the scattering momentum ~340 MeV,indicating that the relativistic formulation may be more natural from the viewpoint of effective field theories.展开更多
The hysteresis loop and Mdssbauer spectrum of the heat treated Nd_(3)Fe_(81)B_(16) alloy ribbons annealing at 660℃ for lOmin.have been measured.A coercive field of about 2kOe and an energy product of about 8MGOe are ...The hysteresis loop and Mdssbauer spectrum of the heat treated Nd_(3)Fe_(81)B_(16) alloy ribbons annealing at 660℃ for lOmin.have been measured.A coercive field of about 2kOe and an energy product of about 8MGOe are obtained at room temperature.X-ray diffraction and Mdssbauer spectrum analyses show that the high coercivity may originate from the Fe_(3)B phase containing Nd.The value of remanence and energy product in this alloy are much higher than those of anisotropic BaFe_(12)O_(19) ferrite.It may be used as a cheap permanent magnet.展开更多
Applying the classical Lie symmetry approach to the barotropic and quasi-geostrophic potential vorticity equation without forcing and dissipation on a β-plane channel, we find a new symmetry, which is not presented i...Applying the classical Lie symmetry approach to the barotropic and quasi-geostrophic potential vorticity equation without forcing and dissipation on a β-plane channel, we find a new symmetry, which is not presented in a previous work [F. Huang, Commun. Theor. Phys. （Beijing, China） 42 （2004） 903]. A general finite transformation group is obtained based on the full Lie point symmetry, Furthermore, two new types of similarity reduction solutions are obtained.展开更多
Rams spectra of the internal modes of ND^(+)_(4)-ion in (ND_(4))_(2)PbCl_(6) crystal have been recorded in the temperature range of 5-300 K.A new structural phase tratisition was observed at 34 K be-ca-use of deuteriu...Rams spectra of the internal modes of ND^(+)_(4)-ion in (ND_(4))_(2)PbCl_(6) crystal have been recorded in the temperature range of 5-300 K.A new structural phase tratisition was observed at 34 K be-ca-use of deuterium effect.Discontinuous behaviours of the internal modes of the ND 4-ion at this temperature show that the structural transition is one of first order.展开更多
The magnetization curves at 1.5K and Curie temperature of amorphow (Fe_(100-x)B_(x))_(88)Nd_(12±ε) alloys were measured.Their spontaneous magnetizations is explained by a noncollinear structure.The average magne...The magnetization curves at 1.5K and Curie temperature of amorphow (Fe_(100-x)B_(x))_(88)Nd_(12±ε) alloys were measured.Their spontaneous magnetizations is explained by a noncollinear structure.The average magnetic moment μ_(Fe) per Fe atom decreases monotonically with increasing x,and becomes more rapid when x>24.The B content dependence of Curie temperature shows a mazimum at x=15.At x<15,the increase of T_(c) with x may be attributed to the indirect exchange interactions between Fe-Fe atoms.展开更多
Sphere unfolding relationships are revisited with a specific focus on the analysis of segmented digital images of microstructures. Since the features of such images are most easily quantified by counting pixels, the r...Sphere unfolding relationships are revisited with a specific focus on the analysis of segmented digital images of microstructures. Since the features of such images are most easily quantified by counting pixels, the required equations are re-derived in terms of the histogram of areas (instead of diameters or radii) as inputs and it is shown that a substitution can be made that simplifies the calculation. A practical method is presented for utilizing negative number fraction bins (which sometimes arise from erroneous assumptions and/or insufficient numbers of observations) for the creation of error bars. The complete algorithm can be implemented in a spreadsheet. The derived unfolding equations are explored using both linear and logarithmic binning schemes, and the pros and cons of both binning schemes are illustrated using simulated data. The effects of the binning schemes on the stereological results are demonstrated and discussed with reference to their consequences for practical materials characterization situations, allowing for the suggestion of guidelines for proper application of this, and other, distribution-free stereological methods.展开更多
Despite the simple structure of male conifer cones, there is an enormous variability in cone properties observed upon more careful examination. The diversity ranges from simple cones to compound cones. Moreover, cones...Despite the simple structure of male conifer cones, there is an enormous variability in cone properties observed upon more careful examination. The diversity ranges from simple cones to compound cones. Moreover, cones can be distinguished according to different spatial distributions on the tree. Simple cones are distributed either as solitary cones or as fascicular or clustered aggregations, while compound cones only exhibit fascicular or clustered aggregations. Here, we demonstrate that these different spatial distribution patterns correlate with distinct leaf types and variable branching frequencies. Furthermore, we provide new insights into the evolution of the sporangiophore, particularly in Taxaceae. Two notably important and fast-evolving characters of conifers are the number of sporangia per sporangiophore and the number of sporangiophores per cone. We demonstrate, across many species and types of cones, how these characters are able to adjust according to the optimal amount of pollen.展开更多
Sexual morph of didymellaceous taxa are characterized by their ascomata with relatively thin peridium,cylindric-clavate to clavate,short-pedicellate or apedicellate asci,hyaline to brown,1-septate to muriform ascospor...Sexual morph of didymellaceous taxa are characterized by their ascomata with relatively thin peridium,cylindric-clavate to clavate,short-pedicellate or apedicellate asci,hyaline to brown,1-septate to muriform ascospores.Its asexual morphs are coelomycetous and comprising pycnidial or acervulus conidiomata,phialidic,hyaline conidiogenous cells and hyaline or pale brown,septate or aseptate conidia.The majority of these cosmopolitan species are plant associated fungi which can be pathogens on a wide range of hosts and some species are of particular relevance for quarantine measures.Recent studies have significantly improved the taxonomy and systematics of didymellaceous taxa based on molecular phylogenetics.In contrast to the accurate and detailed studies on the asexual morphs which are common obligate pathogens,information on their usually saprobic sexual morphs is still limited.Among these phenotypically diverse species,spore characteristics are quite unique as most have hyaline spores with 0-1 septum,while only Neomicrosphaeropsis and Didymellocamarosporium are reported as producing pigmented,muriform spores.These dematiaceous muriform spores are characteristic of a considerable number of species that may be quite divergent in other characters.During taxonomic investigations on the diversity of didymellaceous taxa,we have isolated species from Alhagi pseudalhagi,Coronilla emerus,Cytisus sp.,Elaeagnus angustifolia and Spartium junceum in Italy,Russia and Uzbekistan.A comprehensive phylogeny,based on four loci(ITS,LSU,rpb2 and tub2)is used to infer species relationships.Comprehensive morphological descriptions and in-depth phylogenetic investigations of five new species viz.Ascochyta coronillae-emeri,Microsphaeropsis spartii-juncei,Neomicrosphaeropsis alhagi-pseudalhagi,N.cytisicola and N.elaeagni are presented.展开更多
基金Funding by Ministerium für Wirtschaft,Innovation,Digitalisierung und Energie des Landes Nordrhein-Westfalen。
文摘This contribution presents a novel wear dependent virtual flow rate sensor for single stage single lobe progressing cavity pumps. We study the wear-induced material loss of the pump components and the impact of this material loss on the volumetric efficiency. The results are combined with an established backflow model to implement a backflow calculation procedure that is adaptive to wear. We use a laboratory test setup with a highly abrasive fluid and operate a pump from new to worn condition to validate our approach. The obtained measurement data show that the presented virtual sensor is capable of calculating the flow rate of a pump being subject to wear during its regular operation.
基金supported in part by the National Natural Science Foundation of China(Grant Nos.12070131001,12125507,11835015,and 12047503)the Deutsche Forschungsgemeinschaft(DFG)through the funds provided to the Sino-German Collaborative Research Center TRR110“Symmetries and the Emergence of Structure in QCD”(Project-ID 196253076)+4 种基金the Chinese Academy of Sciences(CAS)(Grant Nos.YSBR-101 and XDB34030000)the EU STRONG-2020 project under the program H2020-INFRAIA-2018-1(Grant No.824093)the Generalitat valenciana(GVA)for the project with ref.CIDEGENT/2019/015supported by the Slovenian Research Agency(research core Funding No.P1-0035)by CAS President’s International Fellowship Initiative(PIFI)(Grant No.2024PVA0004)。
文摘In 2021,the Belle collaboration reported the first observation of a new structure in theψ(2S)γfinal state produced in the two-photon fusion process.In the hadronic molecule picture,this new structure can be associatedwith the shallow isoscalar D*D* bound state and as such is an excellent candidate for the spin-2 partner of the X(3872)with the quantum numbers J^(PC)=2^(++)conventionally named X_(2).
基金the National Key Research and Development Program of China(No.2016YFB0701100)the National Natural Science Foundation of China(Nos.51802015 and 51890893)Fundamental Research Funds for the Central Universities(FRFTP-16-028A1)。
文摘Building a covalently connected structure with accelerated photo-induced electrons and charge-carrier separation between semiconductors could enhance the photocatalytic performance.In this work,we report a facile and novel seed growth method to coat NH2-MIL-125 MOFs with crystalline and porous covalent organic frameworks(COFs)materials and form a range of NH2-MIL-125@TAPB-PDA nanocomposites with different thicknesses of COF shell.The introduction of appropriate content of COF could not only modify the intrinsic electronic and optical properties,but also enhance the photocatalytic activity distinctly.Especially,NH2-MIL-125@TAPB-PDA-3 with COF shell thickness of around 20nm exhibited the highest yield(94.7%)of benzaldehyde which is approximately 2.5 and 15.5 times as that of parental NH2-MIL-125 and COF,respectively.The promoted photocatalytic performance of hybrid materials was mainly owing to the enhanced photo-induced charge carriers transfer between the MOF and COF through the covalent bond.In addition,a possible mechanism to elucidate the process of photocatalysis was explored.Therefore,this kind of MOF-based photocatalysts possesses great potentials in future green organic synthesis.
基金The author thanks Tieren Gao,Peer Decker,Alan Savan,and Manfred Wuttig for fruitful discussions.The authors gratefully acknowledge funding support by the National Science Foundation Graduate Research Fellowship Program(DGE 1322106).
文摘Ni-Ti-based shape memory alloys(SMAs)have found widespread use in the last 70 years,but improving their functional stability remains a key quest for more robust and advanced applications.Named for their ability to retain their processed shape as a result of a reversible martensitic transformation,SMAs are highly sensitive to compositional variations.Alloying with ternary and quaternary elements to finetune the lattice parameters and the thermal hysteresis of an SMA,therefore,becomes a challenge in materials exploration.Combinatorial materials science allows streamlining of the synthesis process and data management from multiple characterization techniques.In this study,a composition spread of Ni-Ti-Cu-V thin-film library was synthesized by magnetron co-sputtering on a thermally oxidized Si wafer.Composition-dependent phase transformation temperature and microstructure were investigated and determined using high-throughput wavelength dispersive spectroscopy,synchrotron X-ray diffraction,and temperature-dependent resistance measurements.Of the 177 compositions in the materials library,32 were observed to have shape memory effect,of which five had zero or near-zero thermal hysteresis.These compositions provide flexibility in the operating temperature regimes that they can be used in.A phase map for the quaternary system and correlations of functional properties are discussed w让h respect to the local microstructure and composition of the thin-film library.
基金The financial support from Hebei Provincial Science and Technology Program of China(Grant no.E2019202234)Research Foundation from Education Department of Hebei Province(Grant no.BJ2018026)-Outstanding Young Talents Plan is acknowledged.
文摘16 Mg-Al-Zn-Bi quaternary alloys were utilized to measure the phase equilibria and transformation temperatures in the Mg-rich Mg-Al-Zn-Bi quaternary system by means of the X-ray diffraction,electron probe micro-analysis and differential scanning calorimetry techniques.The isothermal section at 400℃and three vertical sections along Mg-8 wt%Al-0.75 wt%Zn-vBi,Mg-3.4 wt%Al-0.5 wt%Zn-ABi and Mg-6.9 wt%Al-2.3 wt%Zn-xBi in the Mg-Al-Zn-Bi quaternary system were constructed.Based on the literature data,the ternary Mg-Al-Bi and Mg-Bi-Zn systems were re-assessed using the CALculaiton of PHAse Diagram(CALPHAD)approach.The calculated phase equilibria agree well with the measured data.By directly extrapolating the constituent sub-ternary systems,the thermodynamic database for the Mg-Al-Zn-Bi quaternary system was developed.The remarkable consistency between the predicted phase equilibria and the presently measured data in Mg-Al-Zn-Bi quaternary system further demonstrated the accuracy and reliability of the established thermodynamic database.After that,by using the newly developed thermodynamic database,the growth restrict factors and the solidification curves in Bi-containing AZ series magnesium alloys were calculated and analyzed.It was confirmed that the grain size of AZ alloys can be refined with the addition of Bi,and the comp on ent Al had larger grain refinement effect than Bi.Besides,the amount of Bi had also no ticeable effect on the solidification sequence of the AZ alloys.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19905001 and 19975006partially by the Research Fund for the Doctoral Program of Higher Education of Chinathe Sonderforschungsbereich 191 Niedertemperatur Plasmen(Germany)。
文摘A relatively self-consistent theory of dust-acoustic waves in the strongly coupled dusty plasmas containing variable-charge impurities is given.Relevant physical processes such as dust elastic relaxation and dust charge relaxation are taken into account.It is shown that the negative dispersion of dust-acoustic waves due to the strong correlation of dusts is enhanced in the presence of dust-neutral collisions.
基金Yayasan Universiti Teknologi PETRONAS(UTP)for financial support(YUTP Project#0153AA-H10)。
文摘Discovery of the remains of belemnites referred to the Hibolithes sp.from the Jurassic–Cretaceous Pedawan Formation in Sarawak,on the island of Borneo(Malaysia)comprises four fragments of belemnite rostra.The specimens are characterized by multiple fractures and vein filling.Two fragments measuring about 130 mm are relatively intact,with only part of the alveolar region missing;a third piece represents the middle part of a rostrum,and the fourth specimen is too fragmentary to be assigned to any specific part of the rostrum.Based on specimen characteristics,a Tithonian–Hauterivian age is plausible.The sedimentary succession that yielded the belemnite material comprises thick shale that reflects the Te division of Bouma sequence.The occurrence of a Hibolithes taxon in the uppermost Jurassic to lowermost Cretaceous Pedawan Formation sediments in Borneo reflects a near to global palaeobiogeographic distribution of this genus.
基金Supported by the China Scholarship Council,the National Natural Science Foundation of China(Grant Nos.11375024,11522539,11735003,11335002,and 11775099)NSFC and DFG through funds provided to the Sino-German CRC 110“Symmetries and the Emergence of Structure in QCD”(NSFC Grant No.11621131001,DFG Grant No.TRR110)+2 种基金the China Postdoctoral Science Foundation(Grant Nos.2016M600845 and 2017T100008)the Major State 973 Program of China(Grant No.2013CB834400)the Fundamental Research Funds for the Central Universities。
文摘Recently,a relativistic chiral nucleon-nucleon interaction was formulated up to leading order,which provides a good description of the phase shifts of J≤1 partial waves[Chin.Phys.C 42(2018)014103].Nevertheless,a separable regulator function that is not manifestly covariant was used in solving the relativistic scattering equation.In the present work,we first explore a covariant and separable form factor to regularize the kernel potential and then apply it to study the simplest but most challenging ^(1)S_(0) channel which features several lowenergy scales.In addition to being self-consistent,we show that the resulting relativistic potential can describe quite well the unique features of the ^(1)S_(0) channel at leading order,in particular the pole position of the virtual bound state and the zero amplitude at the scattering momentum ~340 MeV,indicating that the relativistic formulation may be more natural from the viewpoint of effective field theories.
文摘The hysteresis loop and Mdssbauer spectrum of the heat treated Nd_(3)Fe_(81)B_(16) alloy ribbons annealing at 660℃ for lOmin.have been measured.A coercive field of about 2kOe and an energy product of about 8MGOe are obtained at room temperature.X-ray diffraction and Mdssbauer spectrum analyses show that the high coercivity may originate from the Fe_(3)B phase containing Nd.The value of remanence and energy product in this alloy are much higher than those of anisotropic BaFe_(12)O_(19) ferrite.It may be used as a cheap permanent magnet.
基金The project supported by the Alexander von Humboldt Foundationthe Youth Foundation of Shanghai Jiao Tong UniversityNational Natural Science Foundation of China under Grant No.10475055
文摘Applying the classical Lie symmetry approach to the barotropic and quasi-geostrophic potential vorticity equation without forcing and dissipation on a β-plane channel, we find a new symmetry, which is not presented in a previous work [F. Huang, Commun. Theor. Phys. （Beijing, China） 42 （2004） 903]. A general finite transformation group is obtained based on the full Lie point symmetry, Furthermore, two new types of similarity reduction solutions are obtained.
文摘Rams spectra of the internal modes of ND^(+)_(4)-ion in (ND_(4))_(2)PbCl_(6) crystal have been recorded in the temperature range of 5-300 K.A new structural phase tratisition was observed at 34 K be-ca-use of deuterium effect.Discontinuous behaviours of the internal modes of the ND 4-ion at this temperature show that the structural transition is one of first order.
文摘The magnetization curves at 1.5K and Curie temperature of amorphow (Fe_(100-x)B_(x))_(88)Nd_(12±ε) alloys were measured.Their spontaneous magnetizations is explained by a noncollinear structure.The average magnetic moment μ_(Fe) per Fe atom decreases monotonically with increasing x,and becomes more rapid when x>24.The B content dependence of Curie temperature shows a mazimum at x=15.At x<15,the increase of T_(c) with x may be attributed to the indirect exchange interactions between Fe-Fe atoms.
文摘Sphere unfolding relationships are revisited with a specific focus on the analysis of segmented digital images of microstructures. Since the features of such images are most easily quantified by counting pixels, the required equations are re-derived in terms of the histogram of areas (instead of diameters or radii) as inputs and it is shown that a substitution can be made that simplifies the calculation. A practical method is presented for utilizing negative number fraction bins (which sometimes arise from erroneous assumptions and/or insufficient numbers of observations) for the creation of error bars. The complete algorithm can be implemented in a spreadsheet. The derived unfolding equations are explored using both linear and logarithmic binning schemes, and the pros and cons of both binning schemes are illustrated using simulated data. The effects of the binning schemes on the stereological results are demonstrated and discussed with reference to their consequences for practical materials characterization situations, allowing for the suggestion of guidelines for proper application of this, and other, distribution-free stereological methods.
文摘Despite the simple structure of male conifer cones, there is an enormous variability in cone properties observed upon more careful examination. The diversity ranges from simple cones to compound cones. Moreover, cones can be distinguished according to different spatial distributions on the tree. Simple cones are distributed either as solitary cones or as fascicular or clustered aggregations, while compound cones only exhibit fascicular or clustered aggregations. Here, we demonstrate that these different spatial distribution patterns correlate with distinct leaf types and variable branching frequencies. Furthermore, we provide new insights into the evolution of the sporangiophore, particularly in Taxaceae. Two notably important and fast-evolving characters of conifers are the number of sporangia per sporangiophore and the number of sporangiophores per cone. We demonstrate, across many species and types of cones, how these characters are able to adjust according to the optimal amount of pollen.
基金the Committee for Coordination Science and Technology Development under the Cabinet of Ministers of Uzbekistan for research support(#P3-2014-0830174425).
文摘Sexual morph of didymellaceous taxa are characterized by their ascomata with relatively thin peridium,cylindric-clavate to clavate,short-pedicellate or apedicellate asci,hyaline to brown,1-septate to muriform ascospores.Its asexual morphs are coelomycetous and comprising pycnidial or acervulus conidiomata,phialidic,hyaline conidiogenous cells and hyaline or pale brown,septate or aseptate conidia.The majority of these cosmopolitan species are plant associated fungi which can be pathogens on a wide range of hosts and some species are of particular relevance for quarantine measures.Recent studies have significantly improved the taxonomy and systematics of didymellaceous taxa based on molecular phylogenetics.In contrast to the accurate and detailed studies on the asexual morphs which are common obligate pathogens,information on their usually saprobic sexual morphs is still limited.Among these phenotypically diverse species,spore characteristics are quite unique as most have hyaline spores with 0-1 septum,while only Neomicrosphaeropsis and Didymellocamarosporium are reported as producing pigmented,muriform spores.These dematiaceous muriform spores are characteristic of a considerable number of species that may be quite divergent in other characters.During taxonomic investigations on the diversity of didymellaceous taxa,we have isolated species from Alhagi pseudalhagi,Coronilla emerus,Cytisus sp.,Elaeagnus angustifolia and Spartium junceum in Italy,Russia and Uzbekistan.A comprehensive phylogeny,based on four loci(ITS,LSU,rpb2 and tub2)is used to infer species relationships.Comprehensive morphological descriptions and in-depth phylogenetic investigations of five new species viz.Ascochyta coronillae-emeri,Microsphaeropsis spartii-juncei,Neomicrosphaeropsis alhagi-pseudalhagi,N.cytisicola and N.elaeagni are presented.
