Magnesium alloys have been investigated as biodegradable implant materials since the last century. Non-uniform degradation caused by local corrosion limits their application, and no appropriate technology has been use...Magnesium alloys have been investigated as biodegradable implant materials since the last century. Non-uniform degradation caused by local corrosion limits their application, and no appropriate technology has been used in the research. In this study, electrochemical noise has been used to study the pit corrosion on magnesium alloy AZ31 in four types of simulated body solutions, and the data have been analyzed using wavelet analysis and stochastic theory. Combining these with the conventional polarization curves, mass loss tests and scanning electron microscopy, the electrochemical noise results implied that AZ31 alloy in normal saline has the fastest corrosion rate, a high pit initiation rate, and maximum pit growth probability. In Hanks＇ balanced salt solution and phosphate-buffered saline, AZ31 alloy has a high pit initiation rate and larger pit growth probability, while in simulated body fluid, AZ31 alloy has the slowest corrosion rate, lowest pit initiation rate and smallest pit growth probability.展开更多
The symmetry-adapted perturbation theory (SAPT) that has the ability in decompo- sition of the total interaction energy into physically meaningful components is used to provide a more fundamental understanding of inte...The symmetry-adapted perturbation theory (SAPT) that has the ability in decompo- sition of the total interaction energy into physically meaningful components is used to provide a more fundamental understanding of intermolecular forces. This work was motivated by the diffi- culty of standard SAPT in computing the intermolecular interactions for large energetic dimer systems. SAPT based on Kohn-Sham orbitals (SAPT(DFT)) proves computationally efficient for these large systems, but has been shown to perform poorly for interaction energy components. The deficiencies of SAPT(DFT) result from wrong asymptotical behaviors of commonly used exchange-correlation potentials. To remove the deficiencies, two asymptotic corrections by means of van Leeuwen and Baerends (LB) model potential and Fermi-Amaldi (FA) type potential were applied into three small test systems comprising He2, HF2 and (N2)2 and a set of larger ni- tramide dimers at several separations. The results showed that when utilizing newly developed frequency-dependent density susceptibilities (FDDS) technique for computing dispersion energy, the FA asymptotic correction is very effective to circumvent these deficiencies in SAPT(DFT) and yields a good accuracy over the LB correction. The FA corrected SAPT(DFT) approach is capa- ble of correctly predicting all the quantitative trends in binding energies for all test cases and substantially reduces computational cost as compared with the standard SAPT calculations. The successful application of the approach to nitramide dimer demonstrates that it potentially pro- vides a good means to calculate accurately intermolecular forces in larger system such as en- ergetic systems.展开更多
We investigate the baryon number susceptibilities up to fourth order along different freeze-out lines in a holographic QCD model with a critical end point（CEP）, and we propose that the peaked baryon number susceptib...We investigate the baryon number susceptibilities up to fourth order along different freeze-out lines in a holographic QCD model with a critical end point（CEP）, and we propose that the peaked baryon number susceptibilities along the freeze-out line can be used as a clean signature to locate the CEP in the QCD phase diagram.On the temperature and baryon chemical potential plane, the cumulant ratio of the baryon number susceptibilities（up to fourth order） forms a ridge along the phase boundary, and develops a sword-shaped ＂mountain＂ standing upright around the CEP in a narrow and oblate region. The measurement of baryon number susceptibilities from heavy-ion collision experiments is along the freeze-out line. If the freeze-out line crosses the foot of the CEP mountain, then one can observe the peaked baryon number susceptibilities along the freeze-out line, and the kurtosis of the baryon number distributions has the highest magnitude. The data from the first phase of the beam energy scan program at the Relativistic Heavy Ion Collider indicates that there should be a peak of the kurtosis of the baryon number distribution at a collision energy of around 5 Ge V, which suggests that the freeze-out line crosses the foot of the CEP mountain and the summit of the CEP should be located nearby, around a collision energy of 3–7 GeV.展开更多
We study the sign distribution of generalized magnetic susceptibilities in the temperature-external magnetic field plane using the three-dimensional three-state Potts model. We find that the sign of odd-order suscepti...We study the sign distribution of generalized magnetic susceptibilities in the temperature-external magnetic field plane using the three-dimensional three-state Potts model. We find that the sign of odd-order susceptibility is opposite in the symmetric（disorder） and broken（order） phases, but that of the even-order one remains positive when it is far away from the phase boundary. When the critical point is approached from the crossover side, negative fourth-order magnetic susceptibility is observable. It is also demonstrated that non-monotonic behavior occurs in the temperature dependence of the generalized susceptibilities of the energy. The finite-size scaling behavior of the specific heat in this model is mainly controlled by the critical exponent of the magnetic susceptibility in the three-dimensional Ising universality class.展开更多
Active metamaterials embedded with nonlinear elements are able to exhibit strong nonlinearity in microwave regime.However, existing S-parameter based parameter retrieval approaches developed for linear metamaterials d...Active metamaterials embedded with nonlinear elements are able to exhibit strong nonlinearity in microwave regime.However, existing S-parameter based parameter retrieval approaches developed for linear metamaterials do not apply in nonlinear cases. In this paper, a retrieval algorithm of high-order susceptibilities for nonlinear metamaterials is derived.Experimental demonstration shows that, by measuring the power level of each harmonic while sweeping the incident power,high-order susceptibilities of a thin-layer nonlinear metamaterial can be effectively retrieved. The proposed approach can be widely used in the research of active metamaterials.展开更多
The determination of nonlinearities near the band edge of organic and polymeric electro-optic(EO)materials is important from the viewpoint of molecular nonlinear optics(NLO)and photonic device applications.Based on tr...The determination of nonlinearities near the band edge of organic and polymeric electro-optic(EO)materials is important from the viewpoint of molecular nonlinear optics(NLO)and photonic device applications.Based on transmission-mode Stark effect electromodulation(EM)spectroscopy,we study the electric-field-induced changes in optical absorption and refraction of newly developed EO polymers from the visible to near-infrared(NIR)wavelengths and report record-high near-band-edge complex EO effects from poled thin films.Values ofΔn andΔk up to 10^(-3) and 10^(-2) are found at an applied electric field of 2.0×10^(5)-3.0×10^(5)V/cm.The study of linear optical properties of poled films by spectroscopic ellipsometry shows large polinginduced birefringence and a nearly two-fold increase in the extinction coefficients at the extraordinary polarization.Through the Kramers-Kronig analysis,we obtained the real and imaginary second-order nonlinear coefficients up to~3,500 and~5,600 pm/V,respectively,which are believed to be the highest NLO coefficients of poled polymers through the resonance enhancement.Our approach goes beyond the previous works,applicable only to several discrete wavelengths,to a full-spectral analysis with independent verification of slab waveguide measurements.By considering both the electroabsorption and electrorefraction effects,our study overcomes the limitation of the classic qualitative two-level model and provides a quantitative understanding of near-resonance optical nonlinearities of organic EO materials.It can inspire the exploration of high-speed,absorptive,or phase-shifting light-modulators using EO polymers for on-chip applications.展开更多
It is commonly accepted that the system undergoes a crossover at high temperature and low chemical potential beyond the chiral limit case, and the properties of the crossover region are important for researchers to un...It is commonly accepted that the system undergoes a crossover at high temperature and low chemical potential beyond the chiral limit case, and the properties of the crossover region are important for researchers to understand the nature of strong interacting matters of quantum chromodynamics （QCD）. Since at present there is no exact order of parameters of the phase transitions beyond the chiral limit, QCD susceptibilities are widely used as indicators. In this work various susceptibilities are discussed in the framework of Dyson-Schwinger equations. The results show that different kinds of susceptibilities give the same critical end point, which is the bifurcation point of the crossover region and the first order phase transition line of QCD. Nevertheless, different pseudo- critical points are found in the temperature axis. We think that defining a critical band is more suitable in the crossover region.展开更多
A new multidisciplinary study is being carried out in several localities from Outer Carpathians of Central Europe. Outer Carpathians allow studying the Cretaceous-Paleogene (K-Pg) interval of the oceanic facies, inclu...A new multidisciplinary study is being carried out in several localities from Outer Carpathians of Central Europe. Outer Carpathians allow studying the Cretaceous-Paleogene (K-Pg) interval of the oceanic facies, including lower bathyal-abyssal sub-CCD turbidites. Preliminary results of field-measured magnetic susceptibilities from Uzgruň K-Pg section in the Czech Republic are presented.展开更多
Based on the parameterized fully dressed quark propagator proposed by us, the tensor susceptibilities of QCD vacuum and quark vacuum condensates are investigated. Our predicted values of the tensor susceptibilities ar...Based on the parameterized fully dressed quark propagator proposed by us, the tensor susceptibilities of QCD vacuum and quark vacuum condensates are investigated. Our predicted values of the tensor susceptibilities are in agreement with those predicted by many other theoretical models with QCD feature. The results also show that the tensor susceptibility of QCD vacuum strongly depends on flavor of quark but not sensitive to variation of quark vacuum condensates. However, the quark vacuum condensate is very sensitive to the change of cut-off-parameter μ^2 of the integration, that is, it depends on the separation point of perturbative and non-perturbative QCD region. The successful predictions clearly indicate the extensive validity of our parameterized fully dressed quark propagator used here.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51701221 and 51501201)
文摘Magnesium alloys have been investigated as biodegradable implant materials since the last century. Non-uniform degradation caused by local corrosion limits their application, and no appropriate technology has been used in the research. In this study, electrochemical noise has been used to study the pit corrosion on magnesium alloy AZ31 in four types of simulated body solutions, and the data have been analyzed using wavelet analysis and stochastic theory. Combining these with the conventional polarization curves, mass loss tests and scanning electron microscopy, the electrochemical noise results implied that AZ31 alloy in normal saline has the fastest corrosion rate, a high pit initiation rate, and maximum pit growth probability. In Hanks＇ balanced salt solution and phosphate-buffered saline, AZ31 alloy has a high pit initiation rate and larger pit growth probability, while in simulated body fluid, AZ31 alloy has the slowest corrosion rate, lowest pit initiation rate and smallest pit growth probability.
基金supported by the Institute of Chemical Materials(Grant No.42105080107)the National Natural Science Foundation of China(Grant Nos.10176012 and 20173028)China Academy of Engineering Physics(Grant No.2002z0501).
文摘The symmetry-adapted perturbation theory (SAPT) that has the ability in decompo- sition of the total interaction energy into physically meaningful components is used to provide a more fundamental understanding of intermolecular forces. This work was motivated by the diffi- culty of standard SAPT in computing the intermolecular interactions for large energetic dimer systems. SAPT based on Kohn-Sham orbitals (SAPT(DFT)) proves computationally efficient for these large systems, but has been shown to perform poorly for interaction energy components. The deficiencies of SAPT(DFT) result from wrong asymptotical behaviors of commonly used exchange-correlation potentials. To remove the deficiencies, two asymptotic corrections by means of van Leeuwen and Baerends (LB) model potential and Fermi-Amaldi (FA) type potential were applied into three small test systems comprising He2, HF2 and (N2)2 and a set of larger ni- tramide dimers at several separations. The results showed that when utilizing newly developed frequency-dependent density susceptibilities (FDDS) technique for computing dispersion energy, the FA asymptotic correction is very effective to circumvent these deficiencies in SAPT(DFT) and yields a good accuracy over the LB correction. The FA corrected SAPT(DFT) approach is capa- ble of correctly predicting all the quantitative trends in binding energies for all test cases and substantially reduces computational cost as compared with the standard SAPT calculations. The successful application of the approach to nitramide dimer demonstrates that it potentially pro- vides a good means to calculate accurately intermolecular forces in larger system such as en- ergetic systems.
基金Supported by NSFC(11275213,and 11261130311)(CRC 110 by DFG and NSFC)CAS key project KJCX2-EW-N01Youth Innovation Promotion Association of CAS
文摘We investigate the baryon number susceptibilities up to fourth order along different freeze-out lines in a holographic QCD model with a critical end point（CEP）, and we propose that the peaked baryon number susceptibilities along the freeze-out line can be used as a clean signature to locate the CEP in the QCD phase diagram.On the temperature and baryon chemical potential plane, the cumulant ratio of the baryon number susceptibilities（up to fourth order） forms a ridge along the phase boundary, and develops a sword-shaped ＂mountain＂ standing upright around the CEP in a narrow and oblate region. The measurement of baryon number susceptibilities from heavy-ion collision experiments is along the freeze-out line. If the freeze-out line crosses the foot of the CEP mountain, then one can observe the peaked baryon number susceptibilities along the freeze-out line, and the kurtosis of the baryon number distributions has the highest magnitude. The data from the first phase of the beam energy scan program at the Relativistic Heavy Ion Collider indicates that there should be a peak of the kurtosis of the baryon number distribution at a collision energy of around 5 Ge V, which suggests that the freeze-out line crosses the foot of the CEP mountain and the summit of the CEP should be located nearby, around a collision energy of 3–7 GeV.
基金Supported by Fund Project of National Natural Science Foundation of China(11647093,11405088,11521064)Fund Project of Sichuan Provincial Department of Education(16ZB0339)+1 种基金Fund Project of Chengdu Technological University(2016RC004)the Major State Basic Research Development Program of China(2014CB845402)
文摘We study the sign distribution of generalized magnetic susceptibilities in the temperature-external magnetic field plane using the three-dimensional three-state Potts model. We find that the sign of odd-order susceptibility is opposite in the symmetric（disorder） and broken（order） phases, but that of the even-order one remains positive when it is far away from the phase boundary. When the critical point is approached from the crossover side, negative fourth-order magnetic susceptibility is observable. It is also demonstrated that non-monotonic behavior occurs in the temperature dependence of the generalized susceptibilities of the energy. The finite-size scaling behavior of the specific heat in this model is mainly controlled by the critical exponent of the magnetic susceptibility in the three-dimensional Ising universality class.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61401395 and 61604128)the Scientific Research Fund of Zhejiang Provincial Education Department,China(Grant No.Y201533913)the Fundamental Research Funds for the Central Universities,China(Grant Nos.2016QNA4025 and 2016QN81002)
文摘Active metamaterials embedded with nonlinear elements are able to exhibit strong nonlinearity in microwave regime.However, existing S-parameter based parameter retrieval approaches developed for linear metamaterials do not apply in nonlinear cases. In this paper, a retrieval algorithm of high-order susceptibilities for nonlinear metamaterials is derived.Experimental demonstration shows that, by measuring the power level of each harmonic while sweeping the incident power,high-order susceptibilities of a thin-layer nonlinear metamaterial can be effectively retrieved. The proposed approach can be widely used in the research of active metamaterials.
基金supported by the Fundamental Research Project Funding from Shenzhen Science & Technology Innovation Committee (JCYJ20180507181718203)the National Natural Science Foundation of China (21975213)+2 种基金the Research Grants Council (RGC) of Hong Kong (11306320, 11303618, 11210218)the City University of Hong Kong (9610389, 9680263, 9610454)the Innovation and Technology Commission of Hong Kong (ITS/461/18)。
文摘The determination of nonlinearities near the band edge of organic and polymeric electro-optic(EO)materials is important from the viewpoint of molecular nonlinear optics(NLO)and photonic device applications.Based on transmission-mode Stark effect electromodulation(EM)spectroscopy,we study the electric-field-induced changes in optical absorption and refraction of newly developed EO polymers from the visible to near-infrared(NIR)wavelengths and report record-high near-band-edge complex EO effects from poled thin films.Values ofΔn andΔk up to 10^(-3) and 10^(-2) are found at an applied electric field of 2.0×10^(5)-3.0×10^(5)V/cm.The study of linear optical properties of poled films by spectroscopic ellipsometry shows large polinginduced birefringence and a nearly two-fold increase in the extinction coefficients at the extraordinary polarization.Through the Kramers-Kronig analysis,we obtained the real and imaginary second-order nonlinear coefficients up to~3,500 and~5,600 pm/V,respectively,which are believed to be the highest NLO coefficients of poled polymers through the resonance enhancement.Our approach goes beyond the previous works,applicable only to several discrete wavelengths,to a full-spectral analysis with independent verification of slab waveguide measurements.By considering both the electroabsorption and electrorefraction effects,our study overcomes the limitation of the classic qualitative two-level model and provides a quantitative understanding of near-resonance optical nonlinearities of organic EO materials.It can inspire the exploration of high-speed,absorptive,or phase-shifting light-modulators using EO polymers for on-chip applications.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11275097,11475085,11535005,and 11265017the Jiangsu Planned Projects for Postdoctoral Research Funds under Grant No 1402006C+2 种基金the China Postdoctoral Science Foundation under Grant No 2015M571728the Natural Science Foundation of Jiangsu Province under Grant No BK20130078the Guizhou-Provincial Outstanding Youth Science and Technology Talent Cultivation Object Special Funds under Grant No QKHRZ(2013)28
文摘It is commonly accepted that the system undergoes a crossover at high temperature and low chemical potential beyond the chiral limit case, and the properties of the crossover region are important for researchers to understand the nature of strong interacting matters of quantum chromodynamics （QCD）. Since at present there is no exact order of parameters of the phase transitions beyond the chiral limit, QCD susceptibilities are widely used as indicators. In this work various susceptibilities are discussed in the framework of Dyson-Schwinger equations. The results show that different kinds of susceptibilities give the same critical end point, which is the bifurcation point of the crossover region and the first order phase transition line of QCD. Nevertheless, different pseudo- critical points are found in the temperature axis. We think that defining a critical band is more suitable in the crossover region.
基金funded by Czech Science Foundation project no.19-07516S and is in accordance of research plan no.RVO67985831UNESCO/IUGS/IGCP 679 project.
文摘A new multidisciplinary study is being carried out in several localities from Outer Carpathians of Central Europe. Outer Carpathians allow studying the Cretaceous-Paleogene (K-Pg) interval of the oceanic facies, including lower bathyal-abyssal sub-CCD turbidites. Preliminary results of field-measured magnetic susceptibilities from Uzgruň K-Pg section in the Czech Republic are presented.
基金supported by National Natural Science Foundation of China under Grant Nos.10647002 and 10565001the Natural Science Foundation of Guangxi under Grant Nos.0542042,0481030,and 0575020Guangxi University of Technology under Grant No.05006
文摘Based on the parameterized fully dressed quark propagator proposed by us, the tensor susceptibilities of QCD vacuum and quark vacuum condensates are investigated. Our predicted values of the tensor susceptibilities are in agreement with those predicted by many other theoretical models with QCD feature. The results also show that the tensor susceptibility of QCD vacuum strongly depends on flavor of quark but not sensitive to variation of quark vacuum condensates. However, the quark vacuum condensate is very sensitive to the change of cut-off-parameter μ^2 of the integration, that is, it depends on the separation point of perturbative and non-perturbative QCD region. The successful predictions clearly indicate the extensive validity of our parameterized fully dressed quark propagator used here.
