A series of PdCu bimetallic catalysts with low Cu and Pd loadings and different Cu:Pd atomic ratios were prepared by conventionally sequential impregnation(CSD)and modified sequential impregnation(MSI)of Cu and Pd for...A series of PdCu bimetallic catalysts with low Cu and Pd loadings and different Cu:Pd atomic ratios were prepared by conventionally sequential impregnation(CSD)and modified sequential impregnation(MSI)of Cu and Pd for selective hydrogenation of acetylene.Characterization indicates that the supported copper(I)nitrate in the PdCu bimetallic catalysts prepared by MSI can be directly reduced to Cu metal particles due to the hydrogen spillover from Pd to Cu(NO3)2 crystals.In addition,for the catalysts prepared by MSI,Pd atoms can form PdCu alloy on the surface of metal particles,however,for the catalysts prepared by CSI,Pd tends to migrate and exist below the surface layer of Cu.Reaction results indicate that compared with CSI,the MSI method enables samples to possess preferable stability as well as comparable reaction activity.This should be due to the MSI method in favor of the formation of PdCu alloy on the surface of metal particles.Moreover,even Pd loading is super low,<0.045 wt-%in this study,by through adjusting Cu loading to an appropriate value,attractive reactivity and selectivity still can be achieved.展开更多
Extracting the equation of state(EOS) and symmetry energy of dense neutron-rich matter from astrophysical observations is a long-standing goal of nuclear astrophysics. To facilitate the realization of this goal, the f...Extracting the equation of state(EOS) and symmetry energy of dense neutron-rich matter from astrophysical observations is a long-standing goal of nuclear astrophysics. To facilitate the realization of this goal, the feasibility of using an explicitly isospin-dependent parametric EOS for neutron star matter was investigated recently in [1–3]. In this contribution, in addition to outlining the model framework and summarizing the most important findings from [1–3], we report a few new results regarding constraining parameters characterizing the highdensity behavior of nuclear symmetry energy. In particular,the constraints on the pressure of neutron star matter extracted from combining the X-ray observations of the neutron star radius, the minimum–maximum mass M=2:01 M_⊙, and causality condition agree very well with those extracted from analyzing the tidal deformability data by the LIGO ? Virgo Collaborations. The limitations of using the radius and/or tidal deformability of neutron stars to constrain the high-density nuclear symmetry energy are discussed.展开更多
We examine critically how tightly the density dependence of nuclear symmetry energy E_(sym)(q) is constrained by the universal equation of state of the unitary Fermi gas EUG(q) considering currently known uncertaintie...We examine critically how tightly the density dependence of nuclear symmetry energy E_(sym)(q) is constrained by the universal equation of state of the unitary Fermi gas EUG(q) considering currently known uncertainties of higher order parameters describing the density dependence of the equation of state of isospin asymmetric nuclear matter. We found that E_(UG)(q) does provide a useful lower boundary for the E_(sym)(q). However, it doesnot tightly constrain the correlation between the magnitude E_(sym)(q_0) and slope L unless the curvature K_(sym)of the symmetry energy at saturation density q_0 is more precisely known. The large uncertainty in the skewness parameters affects the E_(sym)(q_0) versus L correlation by the same almost as significantly as the uncertainty in K_(sym).展开更多
Galvanic replacement, co-impregnation and sequential impregnation have been employed to prepare Pd-Cu bimetallic catalysts with less than 1 wt-% Cu and ca. 0.03 wt-% Pd for selective hydrogenation of acetylene in exce...Galvanic replacement, co-impregnation and sequential impregnation have been employed to prepare Pd-Cu bimetallic catalysts with less than 1 wt-% Cu and ca. 0.03 wt-% Pd for selective hydrogenation of acetylene in excess ethylene. High angle annular dark field-scanning transmission electron microscopy （HAADF-STEM） and H2 chemisorption results confirmed that Pd-Cu singleatom alloy structures were constructed in all three bimetallic catalysts. Catalytic tests indicated that when the conversion of acetylene was above 99%, the selectivity of ethylene of these three single atom alloy catalysts was still more than 73%. Furthermore, the single atom alloy catalyst prepared by sequential incipient wetness impregnation was found to have the best stability among the three procedures used.展开更多
Based on the modified isospin-dependent quantum molecular dynamics model, the number of emitted nucleons in a photonuclear reaction is studied with different symmetry potentials and different isospin-dependent nucleon...Based on the modified isospin-dependent quantum molecular dynamics model, the number of emitted nucleons in a photonuclear reaction is studied with different symmetry potentials and different isospin-dependent nucleonnucleon （N N） collision cross sections. It is found that the number of emitted nucleons is sensitive to the isospin-dependent nucleon-nucleon cross section when the photon＇s energy is higher than 150 MeV, while it is insensitive to symmetry potential. The number of emitted neutrons is more sensitive to N N collision cross sections than that of protons. It is realized that the number of emitted neutrons can be used as a sensitive probe to extract the information of the isospin-dependent N N cross section at high energy photonuclear reactions.展开更多
This paper reports my recent study[1]on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach.An isospin- and momentum-dependent interaction is used in the study.Dependence of density,temp...This paper reports my recent study[1]on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach.An isospin- and momentum-dependent interaction is used in the study.Dependence of density,temperature,and isospin asymmetry of nuclear matter on its shear viscosity have been discussed.Similar to the symmetry energy,the symmetry shear viscosity is defined and its density and temperature dependence are studied.展开更多
Within the transport model IBUU04, we investigate the double neutron/proton ratio of free nucleons taken from two reaction systems using two Sn isotopes at a beam energy of 50 MeV/nucleon and with impact parameters 2f...Within the transport model IBUU04, we investigate the double neutron/proton ratio of free nucleons taken from two reaction systems using two Sn isotopes at a beam energy of 50 MeV/nucleon and with impact parameters 2fm, 4fm and 8fm, respectively. It is found that the double neutron/proton ratio from peripheral collisions is more sensitive to the density dependence of the symmetry energy than those from mid-central and central collisions.展开更多
It has become evident over the past decade that the lack of PA(physical activity)is a major concern for the population at large CDC(Center for Disease Control).This lack is a major reason for the increase in overweigh...It has become evident over the past decade that the lack of PA(physical activity)is a major concern for the population at large CDC(Center for Disease Control).This lack is a major reason for the increase in overweight and obese children(USDHHS,2014).The CDC and the American Heart Association recommend children need at least 60 minutes of play time that is not scheduled PA.The purpose of this research was to examine whether children’s PA will increase if teacher activity increases during unstructured free play time.Students’PA was determined by using the SOPLAY(system for observing play and leisure activity in youth-children).SOPLAY is a validated tool for directly observing PA and associated environmental characteristics in free play settings(e.g.,recess and lunch at school).SOPLAY provides objective data on the number of participants and their PA levels during play and leisure opportunities in targeted areas.Children and teachers in a West Texas Lab School(mean age=4.3 years)on a university campus were studied.Control group data(males=13,female=15)were analyzed and MVPA(moderate to vigorous physical activity)was calculated.Data showed that children spent only 30%of their free-time in the recommended intensity levels.Teachers’(n=5)overall metabolic equivalents(METs)were recorded at 1.13.The experimental group(males=11,female=13)recorded teachers’(n=6)METs at 2.47 and children MVPA at 44%.Both the MVPA and METs were significantly different(p<0.001).The value and importance of unstructured play time are important for children as well as the teachers.Children need time to be creative and explore during play and teachers use this free time for various activities including cognitive breaks or administrative work.A stronger push to get teachers moving should be made as this slight increase in METs produces a significant increase in children’s PA.展开更多
Our understanding of the observed elemental abundance in the universe,stemming from nuclear reactions during the big bang or from nucleosynthesis within stellar environments,requires theoretical analyses based on mult...Our understanding of the observed elemental abundance in the universe,stemming from nuclear reactions during the big bang or from nucleosynthesis within stellar environments,requires theoretical analyses based on multidimensional nucleosynthesis calculations involving hundreds of nuclei connected via thousands of nuclear processes.Up to recently,full nucleosynthesis network calculations remained computationally expensive and prohibitive.展开更多
In the framework of the isospin-dependent quantum molecular dynamics transport model （QMD）, the effects of symmetry potential on the collision number and the neutron-proton bremsstrahlung photon in the reactions of ...In the framework of the isospin-dependent quantum molecular dynamics transport model （QMD）, the effects of symmetry potential on the collision number and the neutron-proton bremsstrahlung photon in the reactions of 40Ca＋40Ca, 124Sn＋124Sn, 40Ca＋64Zn, 40Ca＋124Sn at different incident beam energies are studied. It is found that the collision number shows moderate sensitivity to the stiffness of the symmetry potential and the number of hard photons calculated with stiff symmetry potential is obviously smaller than that with soft symmetry potential. Thus, the neutron-proton bremsstrahlung photons produced in heavy-ion collisions may be a useful probe for the high-density behavior of the nuclear symmetry potential.展开更多
Network application identification is one of the core elements in network operations and management to provide enhanced network service and security. For accurate identification, an approach using common patterns call...Network application identification is one of the core elements in network operations and management to provide enhanced network service and security. For accurate identification, an approach using common patterns called "signatures" is widely used to compensate the limitations of the traditional transport-layer port-based classification. However, our simulation results indicate that using the signatures generated from a set of well known algorithms may lead to very poor identification performance, with less than 60% of true positives even in an optimal case. To improve the quality of signatures, we present a technique in this paper, which consists of two steps:(i) pairwise merging to consider every possible combination of the initially collected signatures to reduce their specificity that causes the signatures to be less common;and (ii) signature reduction to identify effective signatures with greater importance from a large set of signatures produced in the merging step, so as to manage the space/time complexity in the identification process for greater scalability. Our experimental results show that the proposed technique can dramatically improve the performance, even with a small number of signatures (e.g., 95% true positives rate with 30 signatures per application) which is more compact than the initial signature set.展开更多
The impact of long-memory on the Before-After-Control-Impact (BACI) design and a commonly used nonparametric alternative, Randomized Intervention Analysis (RIA), is examined. It is shown the corrections used based on ...The impact of long-memory on the Before-After-Control-Impact (BACI) design and a commonly used nonparametric alternative, Randomized Intervention Analysis (RIA), is examined. It is shown the corrections used based on short-memory processes are not adequate. Long-memory series are also known to exhibit spurious structural breaks that can be mistakenly attributed to an intervention. Two examples from the literature are used as illustrations.展开更多
In this talk,we first briefly review the isospin dependence of the total nucleon effective mass M Jinferred from analyzing nucleon-nucleus scattering data within an isospin-dependent non-relativistic optical potential...In this talk,we first briefly review the isospin dependence of the total nucleon effective mass M Jinferred from analyzing nucleon-nucleus scattering data within an isospin-dependent non-relativistic optical potential model,and the isospin dependence of the nucleon E-mass M;E J obtained from applying the Migdal–Luttinger theorem to a phenomenological single-nucleon momentum distribution in nuclei constrained by recent electron-nucleus scatteringexperiments.Combining information about the isospin dependence of both the nucleon total effective mass and E-mass,we then infer the isospin dependence of nucleon k-mass using the well-known relation M_J~*=M_ J^(*1E).Implications of the results on the nucleon mean free path in neutron-rich matter are discussed.展开更多
Biharmonic maps are generalizations of harmonic maps. A well-known result on harmonic maps between surfaces shows that there exists no harmonic map from a torus into a sphere(whatever the metrics chosen) in the homoto...Biharmonic maps are generalizations of harmonic maps. A well-known result on harmonic maps between surfaces shows that there exists no harmonic map from a torus into a sphere(whatever the metrics chosen) in the homotopy class of maps of Brower degree±1. It would be interesting to know if there exists any biharmonic map in that homotopy class of maps. The authors obtain some classifications on biharmonic maps from a torus into a sphere, where the torus is provided with a flat or a class of non-flat metrics whilst the sphere is provided with the standard metric. The results in this paper show that there exists no proper biharmonic maps of degree±1 in a large family of maps from a torus into a sphere.展开更多
Using relativistic mean field theory, the neutron and the proton density distribution of 56Ni nuclei could be obtained in the ground state and the excited state. Based on the framework of the quantum molecular dynamic...Using relativistic mean field theory, the neutron and the proton density distribution of 56Ni nuclei could be obtained in the ground state and the excited state. Based on the framework of the quantum molecular dynamics model, the 56Ni nuclei have been simulated in ground state and in the neutron or proton excited state. We then used the three different states of 56Ni to collide with the 56Ni in the ground state. To discuss the evolution of the nuclear stopping in different reactions, two kinds of different excited nuclear reactions were studied at different reaction energies and at different impact parameters. Studies have shown that the nuclear stopping of an excited nuclear reaction is sensitive to the isospin-dependent in-medium nucleon-nucleon cross section, compared with the response value of the ground state nuclear reaction. So, it is better for the excited nuclei to extract the isospin dependence of nucleon-nucleon cross section information.展开更多
Nuclear clusters or voids in the inner crust of neutron stars were predicted to have various shapes collectively nicknamed nuclear pasta.The recent review in Ref.[1]by Lopez,Dorso and Frank summarized their systematic...Nuclear clusters or voids in the inner crust of neutron stars were predicted to have various shapes collectively nicknamed nuclear pasta.The recent review in Ref.[1]by Lopez,Dorso and Frank summarized their systematic investigations into properties especially the mor-phological and thermodynamical phase transitions of the nuclear pasta within a Classical Molecular Dynamics model,providing further stimuli to find more observational evidences of the predicted nuclear pasta in neutron stars.展开更多
Turkey and the Kurdistan Regional Government (KRG) of Iraq built a strategic partnership since 2007 based on shared economic and political interests which included energy deals that bypassed Bagdad. Why does Turkey en...Turkey and the Kurdistan Regional Government (KRG) of Iraq built a strategic partnership since 2007 based on shared economic and political interests which included energy deals that bypassed Bagdad. Why does Turkey engage in economic cooperation with the KRG that facilitates Iraqi Kurds’secession from Iraq, when the Turkish preference is against an independent Kurdish state? The chapter focuses on three key factors to explain the enduring Ankara-Erbil relationship:mutual economic interests, containment of the Kurdistan Workers’Party, and regional power politics. The chapter also investigates the question'How will the recent Kurdish referendum for independence impact the strategic partnership between Turkey and the KRG?'Despite Ankara’s harsh reaction towards the referendum, the chapter argues that the recent crisis will not derail the Turkey-KRG ties. Rather, economic, realpolitik and geographical considerations will continue to push the two actors together in the foreseeable future.展开更多
基金support of the National Natural Science Foundation of China(Grant No.1263094)Welch Foundation(No.T-0014)+1 种基金Key Scientific and Technological Projcct of Henan province,China(No.182102410072)Shanxi International Cooperation Project(No.201703D421037)。
文摘A series of PdCu bimetallic catalysts with low Cu and Pd loadings and different Cu:Pd atomic ratios were prepared by conventionally sequential impregnation(CSD)and modified sequential impregnation(MSI)of Cu and Pd for selective hydrogenation of acetylene.Characterization indicates that the supported copper(I)nitrate in the PdCu bimetallic catalysts prepared by MSI can be directly reduced to Cu metal particles due to the hydrogen spillover from Pd to Cu(NO3)2 crystals.In addition,for the catalysts prepared by MSI,Pd atoms can form PdCu alloy on the surface of metal particles,however,for the catalysts prepared by CSI,Pd tends to migrate and exist below the surface layer of Cu.Reaction results indicate that compared with CSI,the MSI method enables samples to possess preferable stability as well as comparable reaction activity.This should be due to the MSI method in favor of the formation of PdCu alloy on the surface of metal particles.Moreover,even Pd loading is super low,<0.045 wt-%in this study,by through adjusting Cu loading to an appropriate value,attractive reactivity and selectivity still can be achieved.
基金国家自然科学基金资助项目(1057507110575119+9 种基金1067508210710172)上海启明星计划基金资助项目(06QA14024)国家重点基础研究发展规划资助项目(2007CB815004)教育部新世纪优秀人才支持计划(NCET-05-0392)教育部留学回国人员基金资助项目US National Science Foundation Awards(PHY-0652548PHY-0757839)Research Corporation under Award(7123)Texas Coordinating Board of Higher Education Award(003565-0004-2007)~~
基金NBZ was supported in part by the China Scholarship Councilthe U.S.Department of Energy,Office of Science,under Award Number DE-SC0013702,the CUSTIPEN(China-U.S.Theory Institute for Physics with Exotic Nuclei)under the U.S.Department of Energy Grant No.DE-SC0009971the National Natural Science Foundation of China under Grant No.11320101004
文摘Extracting the equation of state(EOS) and symmetry energy of dense neutron-rich matter from astrophysical observations is a long-standing goal of nuclear astrophysics. To facilitate the realization of this goal, the feasibility of using an explicitly isospin-dependent parametric EOS for neutron star matter was investigated recently in [1–3]. In this contribution, in addition to outlining the model framework and summarizing the most important findings from [1–3], we report a few new results regarding constraining parameters characterizing the highdensity behavior of nuclear symmetry energy. In particular,the constraints on the pressure of neutron star matter extracted from combining the X-ray observations of the neutron star radius, the minimum–maximum mass M=2:01 M_⊙, and causality condition agree very well with those extracted from analyzing the tidal deformability data by the LIGO ? Virgo Collaborations. The limitations of using the radius and/or tidal deformability of neutron stars to constrain the high-density nuclear symmetry energy are discussed.
基金supported in part by the China Scholarship Councilthe U.S.Department of Energy,Office of Science,under Award Number DE-SC0013702+7 种基金the CUSTIPEN(China-U.S.Theory Institute for Physics with Exotic Nuclei) under the US Department of Energy Grant No.DE-SC0009971the National Natural Science Foundation of China under Grant No.11320101004the Texas Advanced Computing Centersupported in part by the Major State Basic Research Development Program(973Program) of China under Contract Nos.2015CB856904 and 2014CB845401the National Natural Science Foundation of China under Grant Nos.11475243 and 11421505the ‘‘100-talent plan’’ of Shanghai Institute of Applied Physics under Grant Nos.Y290061011and Y526011011 from the Chinese Academy of Sciencesthe Shanghai Key Laboratory of Particle Physics and Cosmology under Grant No.15DZ2272100the Shanghai Pujiang Program under Grant No.13PJ1410600
文摘We examine critically how tightly the density dependence of nuclear symmetry energy E_(sym)(q) is constrained by the universal equation of state of the unitary Fermi gas EUG(q) considering currently known uncertainties of higher order parameters describing the density dependence of the equation of state of isospin asymmetric nuclear matter. We found that E_(UG)(q) does provide a useful lower boundary for the E_(sym)(q). However, it doesnot tightly constrain the correlation between the magnitude E_(sym)(q_0) and slope L unless the curvature K_(sym)of the symmetry energy at saturation density q_0 is more precisely known. The large uncertainty in the skewness parameters affects the E_(sym)(q_0) versus L correlation by the same almost as significantly as the uncertainty in K_(sym).
文摘Galvanic replacement, co-impregnation and sequential impregnation have been employed to prepare Pd-Cu bimetallic catalysts with less than 1 wt-% Cu and ca. 0.03 wt-% Pd for selective hydrogenation of acetylene in excess ethylene. High angle annular dark field-scanning transmission electron microscopy （HAADF-STEM） and H2 chemisorption results confirmed that Pd-Cu singleatom alloy structures were constructed in all three bimetallic catalysts. Catalytic tests indicated that when the conversion of acetylene was above 99%, the selectivity of ethylene of these three single atom alloy catalysts was still more than 73%. Furthermore, the single atom alloy catalyst prepared by sequential incipient wetness impregnation was found to have the best stability among the three procedures used.
基金Supported by the China Scholarship Council Foundation under Grant No 201208310156, and the National Natural Science Foundation of China under Grant No 10905041.
文摘Based on the modified isospin-dependent quantum molecular dynamics model, the number of emitted nucleons in a photonuclear reaction is studied with different symmetry potentials and different isospin-dependent nucleonnucleon （N N） collision cross sections. It is found that the number of emitted nucleons is sensitive to the isospin-dependent nucleon-nucleon cross section when the photon＇s energy is higher than 150 MeV, while it is insensitive to symmetry potential. The number of emitted neutrons is more sensitive to N N collision cross sections than that of protons. It is realized that the number of emitted neutrons can be used as a sensitive probe to extract the information of the isospin-dependent N N cross section at high energy photonuclear reactions.
基金Suppprted by "100-talent plan" of Shanghai Institute of Applied Physics from the Chinese Academy of Sciences(No.Y290061011)
文摘This paper reports my recent study[1]on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach.An isospin- and momentum-dependent interaction is used in the study.Dependence of density,temperature,and isospin asymmetry of nuclear matter on its shear viscosity have been discussed.Similar to the symmetry energy,the symmetry shear viscosity is defined and its density and temperature dependence are studied.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10710172, 10675082 and 10575071, the New Century Excellent Talent Project （NCET） of the Ministry of Education of China under Grant No NCET-05-0392, the Shanghai Rising-Star Program under Grant No 06QA14024, the SRF for ROCS, SEM of China, and the National Basic Research Program of China under Contract No 2007CB815004, the US National Science Foundation Awards PHY-0652548 and PHY-0757839, the Research Corporation under Award No 7123, and the Texas Coordinating Board of Higher Education Award No 003565-0004-2007.
文摘Within the transport model IBUU04, we investigate the double neutron/proton ratio of free nucleons taken from two reaction systems using two Sn isotopes at a beam energy of 50 MeV/nucleon and with impact parameters 2fm, 4fm and 8fm, respectively. It is found that the double neutron/proton ratio from peripheral collisions is more sensitive to the density dependence of the symmetry energy than those from mid-central and central collisions.
文摘It has become evident over the past decade that the lack of PA(physical activity)is a major concern for the population at large CDC(Center for Disease Control).This lack is a major reason for the increase in overweight and obese children(USDHHS,2014).The CDC and the American Heart Association recommend children need at least 60 minutes of play time that is not scheduled PA.The purpose of this research was to examine whether children’s PA will increase if teacher activity increases during unstructured free play time.Students’PA was determined by using the SOPLAY(system for observing play and leisure activity in youth-children).SOPLAY is a validated tool for directly observing PA and associated environmental characteristics in free play settings(e.g.,recess and lunch at school).SOPLAY provides objective data on the number of participants and their PA levels during play and leisure opportunities in targeted areas.Children and teachers in a West Texas Lab School(mean age=4.3 years)on a university campus were studied.Control group data(males=13,female=15)were analyzed and MVPA(moderate to vigorous physical activity)was calculated.Data showed that children spent only 30%of their free-time in the recommended intensity levels.Teachers’(n=5)overall metabolic equivalents(METs)were recorded at 1.13.The experimental group(males=11,female=13)recorded teachers’(n=6)METs at 2.47 and children MVPA at 44%.Both the MVPA and METs were significantly different(p<0.001).The value and importance of unstructured play time are important for children as well as the teachers.Children need time to be creative and explore during play and teachers use this free time for various activities including cognitive breaks or administrative work.A stronger push to get teachers moving should be made as this slight increase in METs produces a significant increase in children’s PA.
文摘Our understanding of the observed elemental abundance in the universe,stemming from nuclear reactions during the big bang or from nucleosynthesis within stellar environments,requires theoretical analyses based on multidimensional nucleosynthesis calculations involving hundreds of nuclei connected via thousands of nuclear processes.Up to recently,full nucleosynthesis network calculations remained computationally expensive and prohibitive.
基金Supported by National Natural Science Foundation of China(10905041,11005157)China Scholarship Council Foundation(201208310156)the Innovation Fund and Project For Graduate Student of Shanghai(JWCXSL1202)
文摘In the framework of the isospin-dependent quantum molecular dynamics transport model （QMD）, the effects of symmetry potential on the collision number and the neutron-proton bremsstrahlung photon in the reactions of 40Ca＋40Ca, 124Sn＋124Sn, 40Ca＋64Zn, 40Ca＋124Sn at different incident beam energies are studied. It is found that the collision number shows moderate sensitivity to the stiffness of the symmetry potential and the number of hard photons calculated with stiff symmetry potential is obviously smaller than that with soft symmetry potential. Thus, the neutron-proton bremsstrahlung photons produced in heavy-ion collisions may be a useful probe for the high-density behavior of the nuclear symmetry potential.
文摘Network application identification is one of the core elements in network operations and management to provide enhanced network service and security. For accurate identification, an approach using common patterns called "signatures" is widely used to compensate the limitations of the traditional transport-layer port-based classification. However, our simulation results indicate that using the signatures generated from a set of well known algorithms may lead to very poor identification performance, with less than 60% of true positives even in an optimal case. To improve the quality of signatures, we present a technique in this paper, which consists of two steps:(i) pairwise merging to consider every possible combination of the initially collected signatures to reduce their specificity that causes the signatures to be less common;and (ii) signature reduction to identify effective signatures with greater importance from a large set of signatures produced in the merging step, so as to manage the space/time complexity in the identification process for greater scalability. Our experimental results show that the proposed technique can dramatically improve the performance, even with a small number of signatures (e.g., 95% true positives rate with 30 signatures per application) which is more compact than the initial signature set.
文摘The impact of long-memory on the Before-After-Control-Impact (BACI) design and a commonly used nonparametric alternative, Randomized Intervention Analysis (RIA), is examined. It is shown the corrections used based on short-memory processes are not adequate. Long-memory series are also known to exhibit spurious structural breaks that can be mistakenly attributed to an intervention. Two examples from the literature are used as illustrations.
基金supported in part by the US Department of Energy’s Office of Science under Award Number DE-SC0013702the CUSTIPEN(China-US Theory Institute for Physics with Exotic Nuclei)under the US Department of Energy Grant No.DESC0009971+6 种基金the National Natural Science Foundation of China Under Grant Nos.11320101004,11275125,11205083 and 11135011the Major State Basic Research Development Program(973 Program)in China under Contract Nos.2013CB834405 and 2015CB856904the‘‘Shu Guang’’project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundationthe Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning,the Science and Technology Commission of Shanghai Municipality(11DZ2260700)the construct program of the key discipline in Hunan province,the Research Foundation of Education Bureau of Hunan Province,China(Grant No.15A159)the Natural Science Foundation of Hunan Province,China(Grant No.2015JJ3103)the Innovation Group of Nuclear and Particle Physics in USC
文摘In this talk,we first briefly review the isospin dependence of the total nucleon effective mass M Jinferred from analyzing nucleon-nucleus scattering data within an isospin-dependent non-relativistic optical potential model,and the isospin dependence of the nucleon E-mass M;E J obtained from applying the Migdal–Luttinger theorem to a phenomenological single-nucleon momentum distribution in nuclei constrained by recent electron-nucleus scatteringexperiments.Combining information about the isospin dependence of both the nucleon total effective mass and E-mass,we then infer the isospin dependence of nucleon k-mass using the well-known relation M_J~*=M_ J^(*1E).Implications of the results on the nucleon mean free path in neutron-rich matter are discussed.
基金supported by the Natural Science Foundation of China(No.11361073)supported by the Natural Science Foundation of Guangxi Province of China(No.2011GXNSFA018127)
文摘Biharmonic maps are generalizations of harmonic maps. A well-known result on harmonic maps between surfaces shows that there exists no harmonic map from a torus into a sphere(whatever the metrics chosen) in the homotopy class of maps of Brower degree±1. It would be interesting to know if there exists any biharmonic map in that homotopy class of maps. The authors obtain some classifications on biharmonic maps from a torus into a sphere, where the torus is provided with a flat or a class of non-flat metrics whilst the sphere is provided with the standard metric. The results in this paper show that there exists no proper biharmonic maps of degree±1 in a large family of maps from a torus into a sphere.
基金Supported by National Natural Science Foundation of China(10905041)Innovation Fund Project for Graduate Students of Shanghai(JWCXSL1202)China Scholarship Council Foundation(201208310156)
文摘Using relativistic mean field theory, the neutron and the proton density distribution of 56Ni nuclei could be obtained in the ground state and the excited state. Based on the framework of the quantum molecular dynamics model, the 56Ni nuclei have been simulated in ground state and in the neutron or proton excited state. We then used the three different states of 56Ni to collide with the 56Ni in the ground state. To discuss the evolution of the nuclear stopping in different reactions, two kinds of different excited nuclear reactions were studied at different reaction energies and at different impact parameters. Studies have shown that the nuclear stopping of an excited nuclear reaction is sensitive to the isospin-dependent in-medium nucleon-nucleon cross section, compared with the response value of the ground state nuclear reaction. So, it is better for the excited nuclei to extract the isospin dependence of nucleon-nucleon cross section information.
基金B. A. Li is supported in part by the U.S.D epartm ent of Energy, Office of Science, under Award Number DESC0013702the CUSTIPEN (China-U.S. Theory Institute for Physics with Exotic Nuclei) under the US D epartment of Energy Grant No. DE-SC0009971.
文摘Nuclear clusters or voids in the inner crust of neutron stars were predicted to have various shapes collectively nicknamed nuclear pasta.The recent review in Ref.[1]by Lopez,Dorso and Frank summarized their systematic investigations into properties especially the mor-phological and thermodynamical phase transitions of the nuclear pasta within a Classical Molecular Dynamics model,providing further stimuli to find more observational evidences of the predicted nuclear pasta in neutron stars.
文摘Turkey and the Kurdistan Regional Government (KRG) of Iraq built a strategic partnership since 2007 based on shared economic and political interests which included energy deals that bypassed Bagdad. Why does Turkey engage in economic cooperation with the KRG that facilitates Iraqi Kurds’secession from Iraq, when the Turkish preference is against an independent Kurdish state? The chapter focuses on three key factors to explain the enduring Ankara-Erbil relationship:mutual economic interests, containment of the Kurdistan Workers’Party, and regional power politics. The chapter also investigates the question'How will the recent Kurdish referendum for independence impact the strategic partnership between Turkey and the KRG?'Despite Ankara’s harsh reaction towards the referendum, the chapter argues that the recent crisis will not derail the Turkey-KRG ties. Rather, economic, realpolitik and geographical considerations will continue to push the two actors together in the foreseeable future.
