We provide solutions to Einsteins field equations for a model of a spherically symmetric anisotropic fluid distribution, relevant to the description of compact stars. The central matter-energy density, radial and tang...We provide solutions to Einsteins field equations for a model of a spherically symmetric anisotropic fluid distribution, relevant to the description of compact stars. The central matter-energy density, radial and tangential pressures, red shift and speed of sound are positive definite and are decreasing monotonically with increasing radial distance from the center of matter distribution of astrophysical object. The causality condition is satisfied for complete fluid distribution. The central value of anisotropy is zero and is increasing monotonically with increasing radial distance from the center of the distribution. The adiabatic index is increasing with increasing radius of spherical fluid distribution. The stability conditions in relativistic compact star are also discussed in our investigation. The solution is representing the realistic objects such as SAXJ1808.4-3658, HerX-1, 4U1538-52, LMC X-4, CenX-3, VelaX-1, PSRJ1614-2230 and PSRJ0348+0432 with suitable conditions.展开更多
Star SP320S票据打印机是广泛应用于高速公路收费系统、ECR、电子、CAT、计算机外设,以及餐饮业厨房打印机等领域。Star SP320S票据打印机具有丰富的打印功能,包括扩展字符集、反转字符打印、下划线等,可通过软件编程的方法进行设定,是...Star SP320S票据打印机是广泛应用于高速公路收费系统、ECR、电子、CAT、计算机外设,以及餐饮业厨房打印机等领域。Star SP320S票据打印机具有丰富的打印功能,包括扩展字符集、反转字符打印、下划线等,可通过软件编程的方法进行设定,是一款高效稳定的9针高速双向票据打印机。展开更多
We describe the general structure of the well known S255IR high mass star forming region, as revealed by our recent ALMA observations. The data indicate a physical relation exists between the major clumps SMA1 and SMA...We describe the general structure of the well known S255IR high mass star forming region, as revealed by our recent ALMA observations. The data indicate a physical relation exists between the major clumps SMA1 and SMA2. The driving source of the extended high velocity, well collimated bipolar outflow, is not the most pronounced disk-like SMA1 clump harboring a 20M⊙ young star （S255 NIRS3）, as was assumed earlier. Apparently, it is the less evolved SMA2 clump, which drives the outflow and contains a compact rotating structure （probably a disk）. At the same time, the SMA 1 clump drives another outflow, with a larger opening angle. The molecular line data do not show an outflow from the SMA3 clump （NIRS 1）, which was suggested by IR studies of this region.展开更多
First business: to clean a tea pot. Income: RMB 0.20 (less than 10 US cents at the time). Second business: to clean a boiler. Income: RMB 1, 200. Three months later, incomereached RMB 240, 000. Ten years later, the co...First business: to clean a tea pot. Income: RMB 0.20 (less than 10 US cents at the time). Second business: to clean a boiler. Income: RMB 1, 200. Three months later, incomereached RMB 240, 000. Ten years later, the company had 350 subsidiaries across China and four joint ventures abroad, with an annual output value of more than RMB 300 million. The data are simple but intriguing, recording the history of the Blue展开更多
The concept of local s-countablity is introduced, and the relations between locally s-countable collections and star-countable collections are discussed.
We implement the so-called “complex-plane strategy” for computing general-relativistic polytropic models of uniformly rotating neutron stars. This method manages the problem by performing all numerical integrations,...We implement the so-called “complex-plane strategy” for computing general-relativistic polytropic models of uniformly rotating neutron stars. This method manages the problem by performing all numerical integrations, required within the framework of Hartle’s perturbation method, in the complex plane. We give emphasis on computing corrections up to third order in the angular velocity, and the mass-shedding limit. We also compute the angular momentum, moment of inertia, rotational kinetic energy, and gravitational potential energy of the models considered.展开更多
In this paper we compute general-relativistic polytropic models simulating rigidly rotating, pulsating neutron stars. These relativistic compact objects, with a radius of ~10 km and mass between ~1.4 and 3.2 solar mas...In this paper we compute general-relativistic polytropic models simulating rigidly rotating, pulsating neutron stars. These relativistic compact objects, with a radius of ~10 km and mass between ~1.4 and 3.2 solar masses, are closely related to pulsars. We emphasize on computing the change in the pulsation eigenfrequencies owing to a rigid rotation, which, in turn, is a decisive issue for studying stability of such objects. In our computations, we keep rotational perturbation terms of up to second order in the angular velocity.展开更多
The attempt has been taken to calculate the density of stars possessing quark matter core using sphere packing concept of crystallography. The quark matter has been taken as solid in nature as predicted in references ...The attempt has been taken to calculate the density of stars possessing quark matter core using sphere packing concept of crystallography. The quark matter has been taken as solid in nature as predicted in references 36 and 37, and due to immense gravitational pressure at the core of the star the densest packing of quarks as spheres has been assumed to calculate the packing fraction Φ, thus the density ρ of the matter. Three possible types of pickings—mono-sized sphere packing, binary sphere packing and ternary sphere packing, have been worked out using three possible types of quark matter. It has been concluded that no value about the ρ of quark matter can be calculated using binary and ternary packing conditions and for mono-sized packing condition different flavor quark matters of different values in the density have been calculated using results from the experiments done by HI, ZEUS, L3 and CDF Collaborations about the radius limit of quark. For example, for u quark matter ρ ranges from 4.0587 × 1048 - 7.40038 × 1048 MeV/c2 cm3 using results of L3 Collaboration, for s quark matter 15.91794 × 1048 - 17.6866 × 1048 MeV/c2 cm3, etc.展开更多
The mass limit of neutron star has still remained a mystery. The existing Tolman-Oppenheimer-Volkoff (TOV) equation for calculating the limit always gives different values, by introducing different assumptions and hav...The mass limit of neutron star has still remained a mystery. The existing Tolman-Oppenheimer-Volkoff (TOV) equation for calculating the limit always gives different values, by introducing different assumptions and having been predicted like 0.7 Mo, 3.2 Mo, 3.6 Mo, where Mo = 1.98 × 1030 Kg. There is a need of some better technique to adopt other than TOV relation to seek out the value. In this paper, a new relation between the mass of the collapsing star and its average density ρ′ has been derived and used to calculate the limit of neutron star. The conditions in radii between Schwarz Child’s radius and the actual radius of the collapsing star have been introduced to calculate the mass of star above which it will transform into a black hole and below it to a neutron star. A new constant, JN = 8.53707554 × 1039 N-3/2s-3Kg3 has been proposed with which if we introduce the average density of the collapsing neutron star, its mass limit can be calculated very easily. By putting the most possible mass density, which is the minimum required density for a collapsing star to transform into the black hole, it has been found that the mass limit of neutron star is quite higher than it has been assumed. The definition for black hole has also been re-defined on the basis of said radii conditions.展开更多
Prof. Zhou Peiyuan (P.Y.Chou) was a celebrated scientist, educationalist and social activist well-known both at home and abroad. He was an outstanding leader in the Chinese science and technology community, a founder ...Prof. Zhou Peiyuan (P.Y.Chou) was a celebrated scientist, educationalist and social activist well-known both at home and abroad. He was an outstanding leader in the Chinese science and technology community, a founder of modern mechanics in China, a fighter dedicated to world peace and an international envoy of peace and goodwill sent by the Chinese people as well as a peopleto-people diplomat for the promotion ofinternational exchange and cooperation in science and technology.展开更多
In 2011, Jun Ni published the solution of the Tolman-Oppenheimer-Volkoff equations describing the structure of stable neutron stars, which implies that 1) there is no upper mass limit of these objects, 2) their outer ...In 2011, Jun Ni published the solution of the Tolman-Oppenheimer-Volkoff equations describing the structure of stable neutron stars, which implies that 1) there is no upper mass limit of these objects, 2) their outer physical surface is always situated above the corresponding event horizon, and 3) the object is a hollow sphere with the inner physical surface and cavity inside. In our paper, we propose to “purify” the general relativity, as the geometrical theory, from the concept of mass. If we get rid of the concept of mass and Newtonian-type potential, then we obtain such the behavior of gravity which results in the above mentioned stable Ni’s object. It is farther pointed out that the distribution of matter, which is observed as spherically symmetric by the observer in its center, is not longer observed as spherically symmetric by an observer aside the center in a curved spacetime of general relativity. This fact implies, in contrast to the Newtonian physics, the non-zero and outward oriented gravitational attraction of upper layers of star. Ni considered positive energy density and pressure. In addition, gravity had everywhere attractive character. No “exotic” assumption was made. Hence, there is no reason why his concept of hollow sphere should not be applicable to the models of real objects.展开更多
EVERY year, the legendary Shaolin Temple in central China＇s Henan Province welcomes scores of visi- tors eager to master the skills of kungfu, ancient Chinese martial arts. Among them is Guillaume Babila, a young man...EVERY year, the legendary Shaolin Temple in central China＇s Henan Province welcomes scores of visi- tors eager to master the skills of kungfu, ancient Chinese martial arts. Among them is Guillaume Babila, a young man from Cameroon, whose desire to learn kungfu goes back to his childhood, when he first got hold of a martial arts magazine. In the magazine was a photograph of an African man wearing a white robe and holding a sword.展开更多
It＇s not every day you happen to see a dead wolf, an elephant and a horse just lying around. But then this is no ordinary location. The animals are just some of the weird and wonderful props used at a special effects...It＇s not every day you happen to see a dead wolf, an elephant and a horse just lying around. But then this is no ordinary location. The animals are just some of the weird and wonderful props used at a special effects makeup studio located in the Dachang Movie Town, Dachang Hui Autonomous County in Langfang City. north of China＇s Hebei Province.展开更多
ON the evening of August 12, the 30th London Summer Olympic Games came to a close when the flame at the Olympic Stadium was extinguished as each country received one of the cauldrons 204 copper petals. In this year＇s...ON the evening of August 12, the 30th London Summer Olympic Games came to a close when the flame at the Olympic Stadium was extinguished as each country received one of the cauldrons 204 copper petals. In this year＇s Olympics, 10,500 athletes, including nearly 900 African athletes, participated in 302 medal events in all 26 sports.展开更多
文摘We provide solutions to Einsteins field equations for a model of a spherically symmetric anisotropic fluid distribution, relevant to the description of compact stars. The central matter-energy density, radial and tangential pressures, red shift and speed of sound are positive definite and are decreasing monotonically with increasing radial distance from the center of matter distribution of astrophysical object. The causality condition is satisfied for complete fluid distribution. The central value of anisotropy is zero and is increasing monotonically with increasing radial distance from the center of the distribution. The adiabatic index is increasing with increasing radius of spherical fluid distribution. The stability conditions in relativistic compact star are also discussed in our investigation. The solution is representing the realistic objects such as SAXJ1808.4-3658, HerX-1, 4U1538-52, LMC X-4, CenX-3, VelaX-1, PSRJ1614-2230 and PSRJ0348+0432 with suitable conditions.
基金supported by the Russian Foundation for Basic Research(Grant No.15–02–06098)during the preparation of the observations and initial data reductionthe Russian Science Foundation(Grant No.17–12–01256)during the spectral data analysissupport from the European Research Council under the Horizon 2020 Framework Program via the ERC Consolidator Grant CSF-648505
文摘We describe the general structure of the well known S255IR high mass star forming region, as revealed by our recent ALMA observations. The data indicate a physical relation exists between the major clumps SMA1 and SMA2. The driving source of the extended high velocity, well collimated bipolar outflow, is not the most pronounced disk-like SMA1 clump harboring a 20M⊙ young star （S255 NIRS3）, as was assumed earlier. Apparently, it is the less evolved SMA2 clump, which drives the outflow and contains a compact rotating structure （probably a disk）. At the same time, the SMA 1 clump drives another outflow, with a larger opening angle. The molecular line data do not show an outflow from the SMA3 clump （NIRS 1）, which was suggested by IR studies of this region.
文摘First business: to clean a tea pot. Income: RMB 0.20 (less than 10 US cents at the time). Second business: to clean a boiler. Income: RMB 1, 200. Three months later, incomereached RMB 240, 000. Ten years later, the company had 350 subsidiaries across China and four joint ventures abroad, with an annual output value of more than RMB 300 million. The data are simple but intriguing, recording the history of the Blue
基金Foundation item:The NSF(10171043,10271026)of China
文摘The concept of local s-countablity is introduced, and the relations between locally s-countable collections and star-countable collections are discussed.
文摘We implement the so-called “complex-plane strategy” for computing general-relativistic polytropic models of uniformly rotating neutron stars. This method manages the problem by performing all numerical integrations, required within the framework of Hartle’s perturbation method, in the complex plane. We give emphasis on computing corrections up to third order in the angular velocity, and the mass-shedding limit. We also compute the angular momentum, moment of inertia, rotational kinetic energy, and gravitational potential energy of the models considered.
文摘In this paper we compute general-relativistic polytropic models simulating rigidly rotating, pulsating neutron stars. These relativistic compact objects, with a radius of ~10 km and mass between ~1.4 and 3.2 solar masses, are closely related to pulsars. We emphasize on computing the change in the pulsation eigenfrequencies owing to a rigid rotation, which, in turn, is a decisive issue for studying stability of such objects. In our computations, we keep rotational perturbation terms of up to second order in the angular velocity.
文摘The attempt has been taken to calculate the density of stars possessing quark matter core using sphere packing concept of crystallography. The quark matter has been taken as solid in nature as predicted in references 36 and 37, and due to immense gravitational pressure at the core of the star the densest packing of quarks as spheres has been assumed to calculate the packing fraction Φ, thus the density ρ of the matter. Three possible types of pickings—mono-sized sphere packing, binary sphere packing and ternary sphere packing, have been worked out using three possible types of quark matter. It has been concluded that no value about the ρ of quark matter can be calculated using binary and ternary packing conditions and for mono-sized packing condition different flavor quark matters of different values in the density have been calculated using results from the experiments done by HI, ZEUS, L3 and CDF Collaborations about the radius limit of quark. For example, for u quark matter ρ ranges from 4.0587 × 1048 - 7.40038 × 1048 MeV/c2 cm3 using results of L3 Collaboration, for s quark matter 15.91794 × 1048 - 17.6866 × 1048 MeV/c2 cm3, etc.
文摘The mass limit of neutron star has still remained a mystery. The existing Tolman-Oppenheimer-Volkoff (TOV) equation for calculating the limit always gives different values, by introducing different assumptions and having been predicted like 0.7 Mo, 3.2 Mo, 3.6 Mo, where Mo = 1.98 × 1030 Kg. There is a need of some better technique to adopt other than TOV relation to seek out the value. In this paper, a new relation between the mass of the collapsing star and its average density ρ′ has been derived and used to calculate the limit of neutron star. The conditions in radii between Schwarz Child’s radius and the actual radius of the collapsing star have been introduced to calculate the mass of star above which it will transform into a black hole and below it to a neutron star. A new constant, JN = 8.53707554 × 1039 N-3/2s-3Kg3 has been proposed with which if we introduce the average density of the collapsing neutron star, its mass limit can be calculated very easily. By putting the most possible mass density, which is the minimum required density for a collapsing star to transform into the black hole, it has been found that the mass limit of neutron star is quite higher than it has been assumed. The definition for black hole has also been re-defined on the basis of said radii conditions.
文摘Prof. Zhou Peiyuan (P.Y.Chou) was a celebrated scientist, educationalist and social activist well-known both at home and abroad. He was an outstanding leader in the Chinese science and technology community, a founder of modern mechanics in China, a fighter dedicated to world peace and an international envoy of peace and goodwill sent by the Chinese people as well as a peopleto-people diplomat for the promotion ofinternational exchange and cooperation in science and technology.
基金supported,in part,by the VEGA—the Slovak Grant Agency for Science,grant No.2/0031/14by the Slovak Research and Development Agency under the contract No.APVV-0158-11.
文摘In 2011, Jun Ni published the solution of the Tolman-Oppenheimer-Volkoff equations describing the structure of stable neutron stars, which implies that 1) there is no upper mass limit of these objects, 2) their outer physical surface is always situated above the corresponding event horizon, and 3) the object is a hollow sphere with the inner physical surface and cavity inside. In our paper, we propose to “purify” the general relativity, as the geometrical theory, from the concept of mass. If we get rid of the concept of mass and Newtonian-type potential, then we obtain such the behavior of gravity which results in the above mentioned stable Ni’s object. It is farther pointed out that the distribution of matter, which is observed as spherically symmetric by the observer in its center, is not longer observed as spherically symmetric by an observer aside the center in a curved spacetime of general relativity. This fact implies, in contrast to the Newtonian physics, the non-zero and outward oriented gravitational attraction of upper layers of star. Ni considered positive energy density and pressure. In addition, gravity had everywhere attractive character. No “exotic” assumption was made. Hence, there is no reason why his concept of hollow sphere should not be applicable to the models of real objects.
文摘EVERY year, the legendary Shaolin Temple in central China＇s Henan Province welcomes scores of visi- tors eager to master the skills of kungfu, ancient Chinese martial arts. Among them is Guillaume Babila, a young man from Cameroon, whose desire to learn kungfu goes back to his childhood, when he first got hold of a martial arts magazine. In the magazine was a photograph of an African man wearing a white robe and holding a sword.
文摘It＇s not every day you happen to see a dead wolf, an elephant and a horse just lying around. But then this is no ordinary location. The animals are just some of the weird and wonderful props used at a special effects makeup studio located in the Dachang Movie Town, Dachang Hui Autonomous County in Langfang City. north of China＇s Hebei Province.
文摘ON the evening of August 12, the 30th London Summer Olympic Games came to a close when the flame at the Olympic Stadium was extinguished as each country received one of the cauldrons 204 copper petals. In this year＇s Olympics, 10,500 athletes, including nearly 900 African athletes, participated in 302 medal events in all 26 sports.
