Based on the generalized uncertainty principle with maximum momentum arid minimal length, we discuss the equation of state of ideal ultra-relativistic Fermi gases at zero temperature. Maximum momentum avoids the probl...Based on the generalized uncertainty principle with maximum momentum arid minimal length, we discuss the equation of state of ideal ultra-relativistic Fermi gases at zero temperature. Maximum momentum avoids the problem that the Fermi degenerate pressure blows up since the increase of the Fermi energy is not limited. Applying this equation of state to the Tolman-Oppenheimer Volkoff （TOV） equation, the quantum gravitational effects on the cores of compact stars are discussed. In the center of compact stars, we obtain the singularity-free solution of the metric component, gtt ～-（1 ＋ 0.2185×r^2）. By numerically solving the TOV equation, we find that quantum gravity plays an important role in the region r～10^4α0（△x）min. Current observed masses of neutron stars indicate that the dimensionless parameter α0 cannot exceed 10^19.展开更多
Based on the equations of state from the relativistic mean field theory without and with the inclusion of strangeness-bearing hyperons, we study the dimensionless spin parameter j = cJ/（GM2） of uniformly rotat- ing ...Based on the equations of state from the relativistic mean field theory without and with the inclusion of strangeness-bearing hyperons, we study the dimensionless spin parameter j = cJ/（GM2） of uniformly rotat- ing neutron stars. It is shown that the maximum value of the spin parameter jmax of a neutron star rotating at the Keplerian frequency fK is .jmax - 0.7 when the star mass M 〉 0.SM⊙, which is sustained for various versions of equations of state without and with hyperons. The relationship between j and the scaled rotation frequency f /fK is found to be insensitive to the star mass or the adopted equation of state in the models without hyperons. However, the emergence of byperons in neutron stars will lead to an uncertainty of the spin parameter j, which in turn could generate a complexity in the theoretical study of the quasi-periodic oscillations observed in disk-accreting compact-star systems.展开更多
Perturbation methods are employed to calculate time variation in the orbital elements of a compact binary system. It turns out that the semi-major axis and eccentricity exhibit only periodic variations. The longitude ...Perturbation methods are employed to calculate time variation in the orbital elements of a compact binary system. It turns out that the semi-major axis and eccentricity exhibit only periodic variations. The longitude of periastron and mean longitude of epoch exhibit both secular and periodic variation. In addition, the relativistic effects on the time of periastron passage of binary stars are also given. Four compact binary systems (PSRJ0737-3039, PSR1913+16, PSR1543+12 and M33X-7) are considered. Numerical results for both secular and periodic effects are presented, and the possibility of observing them is discussed.展开更多
The angular acceleration due to the spin effect increases the burning rate of solid propellant and changes the motor performance by increasing the operating pressure and decreasing the burning time. So it is important...The angular acceleration due to the spin effect increases the burning rate of solid propellant and changes the motor performance by increasing the operating pressure and decreasing the burning time. So it is important to know the grain regression taken place in the solid propellant rocket motor in the acceleration field. This study represents the grain regression analysis of two-dimensional axis-symmetric star grain configuration of the solid propellant rocket motor with spin induced acceleration effect and pressure effect on burn rate using geometrical and numerical analysis. While the rocket is spinning, the burn rates on each point of the propellant surface are different with its radial distance, acceleration vector angle and surface slope. With the different burn rates on the propellant surface, we analyze the propellant surface perimeter and port area, and these results are compared with those of constant burn rate and burn rate affected by the chamber pressure.展开更多
Considering the gravitational correction through introduction of weakly interacting light vector U bosons, not only the equation of state （EoS） of the neutron star matter, but also the cooling properties of neutron ...Considering the gravitational correction through introduction of weakly interacting light vector U bosons, not only the equation of state （EoS） of the neutron star matter, but also the cooling properties of neutron stars may be changed. In this work, effects of gravitational correction on neutrino emission and cooling of neutron stars in the matter with neutrons, protons, electrons, muons, △- and △0 are studied by the relativistic mean field theory and the related cooling theory. The results show that the effects are sensitive to the ratio of coupling strength to mass squared of U bosons, defined as gu. With increasing gu, the radial region where direct Urca process of nucleons can be allowed in a neutron star with the fixed mass becomes narrower, while the neutrino emissivity is somewhat higher. Moreover, the gravitational correction suppresses the effects of △- on neutrino emission. The gravitational correction leads the star to cool faster, and the higher the gu is, the faster the star cools.展开更多
The theoretical framework developed by A.S. Eddington for the study of the inner structure and stability of the stars has been modified by the author and used in this work to show that knowing the effective temperatur...The theoretical framework developed by A.S. Eddington for the study of the inner structure and stability of the stars has been modified by the author and used in this work to show that knowing the effective temperature and the absolute magnitude, the basic parameters of any gaseous star can be calculated. On the other hand, a possible theoretical explanation of the Hertzsprung-Russel Diagram is presented.展开更多
This paper is devoted to binary stars belonging to the class of eclipsing-variable systems.Photometric and spectroscopic analysis of eclipses allows us to determine geometric parameters of the orbit and physical chara...This paper is devoted to binary stars belonging to the class of eclipsing-variable systems.Photometric and spectroscopic analysis of eclipses allows us to determine geometric parameters of the orbit and physical characteristics of stellar components as well as inclinations of stellar equators to the orbital plane. Estimations of inclinations can be obtained from measurement of the Rossiter-McLaughlin effect, which is discussed using examples of some eccentric binaries with an anomalous apsidal effect. Our task is to find the complete spectrum of solutions of the equation of apsidal motion, depending on the inclinations of the polar axes of the components to the orbital one for these systems, based on their individual spectroscopic and photometric observational data. The matrix of solutions allows us to select those pairs of polar inclinations that provide agreement with the observational apsidal period.展开更多
八角茴香(Illicium verum Hook.f.)属于木兰科植物,是中国特有的药食同源植物,目前研究集中于其化学成分与药理作用的开发利用。然而,八角茴香化学成分的系统鉴定和药理作用的定量数据不足,加工及提取技术缺乏统一规范。综述系统梳理了...八角茴香(Illicium verum Hook.f.)属于木兰科植物,是中国特有的药食同源植物,目前研究集中于其化学成分与药理作用的开发利用。然而,八角茴香化学成分的系统鉴定和药理作用的定量数据不足,加工及提取技术缺乏统一规范。综述系统梳理了八角茴香的主要成分,包括挥发油、黄酮类、酚酸类、倍半萜内酯类等,分析了其抗菌、镇痛、抗炎、抗氧化等药理作用,并总结了提取、分析及鲜料加工等方法的工艺要点,以期为完善八角茴香研究方法与工艺标准,提升资源利用效率和产业化应用提供有力支撑。展开更多
以黑芝麻与螺旋藻为主要原料,研究黑芝麻螺旋藻复合营养饮料的稳定性工艺。首先通过单因素试验法分别考察了蔗糖酯、蒸馏单硬脂酸甘油酯、黄原胶、海藻酸丙二醇酯、羧甲基纤维素钠等乳化剂与稳定剂对饮料的感官和稳定性的影响;在此基础...以黑芝麻与螺旋藻为主要原料,研究黑芝麻螺旋藻复合营养饮料的稳定性工艺。首先通过单因素试验法分别考察了蔗糖酯、蒸馏单硬脂酸甘油酯、黄原胶、海藻酸丙二醇酯、羧甲基纤维素钠等乳化剂与稳定剂对饮料的感官和稳定性的影响;在此基础上,采用星点设计-效应面法优选黑芝麻螺旋藻复合营养饮料的最佳稳定性工艺条件。结果表明:蒸馏单硬脂酸甘油酯用量为0.21%,黄原胶用量为0.04%,海藻酸钠丙二醇酯用量为0.09%;与理论预测值0.850的相对标准偏差(relative standard deviation,RSD)为6.59%。所建立的数学模型具有较好的预测性,所选的工艺条件重现性较好。展开更多
基金Supported by the Fundamental Research Funds for the Central Universities under Grant No ZYGX2009X008
文摘Based on the generalized uncertainty principle with maximum momentum arid minimal length, we discuss the equation of state of ideal ultra-relativistic Fermi gases at zero temperature. Maximum momentum avoids the problem that the Fermi degenerate pressure blows up since the increase of the Fermi energy is not limited. Applying this equation of state to the Tolman-Oppenheimer Volkoff （TOV） equation, the quantum gravitational effects on the cores of compact stars are discussed. In the center of compact stars, we obtain the singularity-free solution of the metric component, gtt ～-（1 ＋ 0.2185×r^2）. By numerically solving the TOV equation, we find that quantum gravity plays an important role in the region r～10^4α0（△x）min. Current observed masses of neutron stars indicate that the dimensionless parameter α0 cannot exceed 10^19.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11175108,U1432119,1146114100,11205075,11375076 and 11475104the Shandong Natural Science Foundation under Grant No ZR2014AQ012the Foundation of Shandong University under Grant No 2015WHWLJH01
文摘Based on the equations of state from the relativistic mean field theory without and with the inclusion of strangeness-bearing hyperons, we study the dimensionless spin parameter j = cJ/（GM2） of uniformly rotat- ing neutron stars. It is shown that the maximum value of the spin parameter jmax of a neutron star rotating at the Keplerian frequency fK is .jmax - 0.7 when the star mass M 〉 0.SM⊙, which is sustained for various versions of equations of state without and with hyperons. The relationship between j and the scaled rotation frequency f /fK is found to be insensitive to the star mass or the adopted equation of state in the models without hyperons. However, the emergence of byperons in neutron stars will lead to an uncertainty of the spin parameter j, which in turn could generate a complexity in the theoretical study of the quasi-periodic oscillations observed in disk-accreting compact-star systems.
文摘Perturbation methods are employed to calculate time variation in the orbital elements of a compact binary system. It turns out that the semi-major axis and eccentricity exhibit only periodic variations. The longitude of periastron and mean longitude of epoch exhibit both secular and periodic variation. In addition, the relativistic effects on the time of periastron passage of binary stars are also given. Four compact binary systems (PSRJ0737-3039, PSR1913+16, PSR1543+12 and M33X-7) are considered. Numerical results for both secular and periodic effects are presented, and the possibility of observing them is discussed.
文摘The angular acceleration due to the spin effect increases the burning rate of solid propellant and changes the motor performance by increasing the operating pressure and decreasing the burning time. So it is important to know the grain regression taken place in the solid propellant rocket motor in the acceleration field. This study represents the grain regression analysis of two-dimensional axis-symmetric star grain configuration of the solid propellant rocket motor with spin induced acceleration effect and pressure effect on burn rate using geometrical and numerical analysis. While the rocket is spinning, the burn rates on each point of the propellant surface are different with its radial distance, acceleration vector angle and surface slope. With the different burn rates on the propellant surface, we analyze the propellant surface perimeter and port area, and these results are compared with those of constant burn rate and burn rate affected by the chamber pressure.
文摘Considering the gravitational correction through introduction of weakly interacting light vector U bosons, not only the equation of state （EoS） of the neutron star matter, but also the cooling properties of neutron stars may be changed. In this work, effects of gravitational correction on neutrino emission and cooling of neutron stars in the matter with neutrons, protons, electrons, muons, △- and △0 are studied by the relativistic mean field theory and the related cooling theory. The results show that the effects are sensitive to the ratio of coupling strength to mass squared of U bosons, defined as gu. With increasing gu, the radial region where direct Urca process of nucleons can be allowed in a neutron star with the fixed mass becomes narrower, while the neutrino emissivity is somewhat higher. Moreover, the gravitational correction suppresses the effects of △- on neutrino emission. The gravitational correction leads the star to cool faster, and the higher the gu is, the faster the star cools.
文摘The theoretical framework developed by A.S. Eddington for the study of the inner structure and stability of the stars has been modified by the author and used in this work to show that knowing the effective temperature and the absolute magnitude, the basic parameters of any gaseous star can be calculated. On the other hand, a possible theoretical explanation of the Hertzsprung-Russel Diagram is presented.
文摘This paper is devoted to binary stars belonging to the class of eclipsing-variable systems.Photometric and spectroscopic analysis of eclipses allows us to determine geometric parameters of the orbit and physical characteristics of stellar components as well as inclinations of stellar equators to the orbital plane. Estimations of inclinations can be obtained from measurement of the Rossiter-McLaughlin effect, which is discussed using examples of some eccentric binaries with an anomalous apsidal effect. Our task is to find the complete spectrum of solutions of the equation of apsidal motion, depending on the inclinations of the polar axes of the components to the orbital one for these systems, based on their individual spectroscopic and photometric observational data. The matrix of solutions allows us to select those pairs of polar inclinations that provide agreement with the observational apsidal period.
文摘八角茴香(Illicium verum Hook.f.)属于木兰科植物,是中国特有的药食同源植物,目前研究集中于其化学成分与药理作用的开发利用。然而,八角茴香化学成分的系统鉴定和药理作用的定量数据不足,加工及提取技术缺乏统一规范。综述系统梳理了八角茴香的主要成分,包括挥发油、黄酮类、酚酸类、倍半萜内酯类等,分析了其抗菌、镇痛、抗炎、抗氧化等药理作用,并总结了提取、分析及鲜料加工等方法的工艺要点,以期为完善八角茴香研究方法与工艺标准,提升资源利用效率和产业化应用提供有力支撑。
文摘以黑芝麻与螺旋藻为主要原料,研究黑芝麻螺旋藻复合营养饮料的稳定性工艺。首先通过单因素试验法分别考察了蔗糖酯、蒸馏单硬脂酸甘油酯、黄原胶、海藻酸丙二醇酯、羧甲基纤维素钠等乳化剂与稳定剂对饮料的感官和稳定性的影响;在此基础上,采用星点设计-效应面法优选黑芝麻螺旋藻复合营养饮料的最佳稳定性工艺条件。结果表明:蒸馏单硬脂酸甘油酯用量为0.21%,黄原胶用量为0.04%,海藻酸钠丙二醇酯用量为0.09%;与理论预测值0.850的相对标准偏差(relative standard deviation,RSD)为6.59%。所建立的数学模型具有较好的预测性,所选的工艺条件重现性较好。
