Based on plasma kinetic theory, the instabilities of self-gravitation systems under perturbation with orbital angular momentum(OAM) are investigated, and the concept of twisted Jeans mode is introduced to describe the...Based on plasma kinetic theory, the instabilities of self-gravitation systems under perturbation with orbital angular momentum(OAM) are investigated, and the concept of twisted Jeans mode is introduced to describe the new phenomenon. The result shows that the growth rate of the Jeans instability is enhanced with the OAM parameter increased, while the critical wave number is consistent with the classical Jeans critical value. It is expected that the present results would give more insight into the evolution and dynamics of a self-gravitational system.展开更多
为解决纺织服装产品工业生产阶段碳足迹评价工作量大、传统核算方法较难实现核算精细化等问题,采用基于模块化理论的碳足迹核算方法对三款牛仔裤产品(男式、女式和儿童牛仔裤)的工业碳足迹进行核算与评价,通过工序层级碳足迹单元(模块)...为解决纺织服装产品工业生产阶段碳足迹评价工作量大、传统核算方法较难实现核算精细化等问题,采用基于模块化理论的碳足迹核算方法对三款牛仔裤产品(男式、女式和儿童牛仔裤)的工业碳足迹进行核算与评价,通过工序层级碳足迹单元(模块)的选择调用与积木式拼装实现产品碳足迹的快速和精准核算。结果表明:男式、女式和儿童牛仔裤从纺纱到制衣过程的碳足迹分别为7.30 kg CO_(2)e/件、7.24 kg CO_(2)e/件和4.16 kg CO_(2)e/件;男式和女式牛仔裤缝制工序(制衣工段中)以及儿童牛仔裤染色与上浆工序(织造工段中)的碳足迹最大,装饰唛和蒸汽的耗用是导致上述两个工序碳足迹较大的主要原因,可通过优化装饰唛的设计、选择更加环保的原材料、采用新型染色技术等手段减少两个工序的碳排放量;电力是产品生产过程中最主要的碳排放源,建议采用清洁电力来替代传统火电。展开更多
Jeans mass is regarded as a crucial factor in the study of nebula collapse.Astronomical data shows that Jeans mass is larger in theory than it is in observation.Someone mentioned that Jeans mass can be modified by usi...Jeans mass is regarded as a crucial factor in the study of nebula collapse.Astronomical data shows that Jeans mass is larger in theory than it is in observation.Someone mentioned that Jeans mass can be modified by using the generalized uncertainty principle(GUP).However,different physical backgrounds lead to different forms of GUP expression.In order to make the theoretical values of Jeans mass and its observed values match better,we use three distinct types of GUPs to correct Jeans mass in this paper.We find that the corrected Jeans masses are smaller than the uncorrected ones,where the Pedram corrected Jeans mass is the minimum and is close to the observed value.In addition,we consider the impact of temperature T and the GUP parameters(η,βandγ)for the corrected Jeans mass.展开更多
In this short note we have reconsidered the Jeans criterion for gravitational contraction of a gas nebula at different temperatures, from the present-day background radiation temperature (2.8 K) to those which existed...In this short note we have reconsidered the Jeans criterion for gravitational contraction of a gas nebula at different temperatures, from the present-day background radiation temperature (2.8 K) to those which existed at the early stage of the Universe. We demonstrate that the initial mass of quasars cannot be of the order of single galaxy masses, but rather 106 solar mass only. If they have larger masses, it must be the result of subsequent accretion process. Nevertheless quasars, formed prior to the stars, were the immediate source of the elements heavier than helium.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.11763006 and 11863004)the fund from the Jiangxi Provincial Key Laboratory of Fusion and Information Control (Grant No.20171BCD40005)the Project of Scientific and Technological Innovation Base of Jiangxi Province (Grant No.20203CCD46008)。
文摘Based on plasma kinetic theory, the instabilities of self-gravitation systems under perturbation with orbital angular momentum(OAM) are investigated, and the concept of twisted Jeans mode is introduced to describe the new phenomenon. The result shows that the growth rate of the Jeans instability is enhanced with the OAM parameter increased, while the critical wave number is consistent with the classical Jeans critical value. It is expected that the present results would give more insight into the evolution and dynamics of a self-gravitational system.
文摘为解决纺织服装产品工业生产阶段碳足迹评价工作量大、传统核算方法较难实现核算精细化等问题,采用基于模块化理论的碳足迹核算方法对三款牛仔裤产品(男式、女式和儿童牛仔裤)的工业碳足迹进行核算与评价,通过工序层级碳足迹单元(模块)的选择调用与积木式拼装实现产品碳足迹的快速和精准核算。结果表明:男式、女式和儿童牛仔裤从纺纱到制衣过程的碳足迹分别为7.30 kg CO_(2)e/件、7.24 kg CO_(2)e/件和4.16 kg CO_(2)e/件;男式和女式牛仔裤缝制工序(制衣工段中)以及儿童牛仔裤染色与上浆工序(织造工段中)的碳足迹最大,装饰唛和蒸汽的耗用是导致上述两个工序碳足迹较大的主要原因,可通过优化装饰唛的设计、选择更加环保的原材料、采用新型染色技术等手段减少两个工序的碳排放量;电力是产品生产过程中最主要的碳排放源,建议采用清洁电力来替代传统火电。
基金the National Natural Science Foundation of China(Grant No.12265007)。
文摘Jeans mass is regarded as a crucial factor in the study of nebula collapse.Astronomical data shows that Jeans mass is larger in theory than it is in observation.Someone mentioned that Jeans mass can be modified by using the generalized uncertainty principle(GUP).However,different physical backgrounds lead to different forms of GUP expression.In order to make the theoretical values of Jeans mass and its observed values match better,we use three distinct types of GUPs to correct Jeans mass in this paper.We find that the corrected Jeans masses are smaller than the uncorrected ones,where the Pedram corrected Jeans mass is the minimum and is close to the observed value.In addition,we consider the impact of temperature T and the GUP parameters(η,βandγ)for the corrected Jeans mass.
文摘In this short note we have reconsidered the Jeans criterion for gravitational contraction of a gas nebula at different temperatures, from the present-day background radiation temperature (2.8 K) to those which existed at the early stage of the Universe. We demonstrate that the initial mass of quasars cannot be of the order of single galaxy masses, but rather 106 solar mass only. If they have larger masses, it must be the result of subsequent accretion process. Nevertheless quasars, formed prior to the stars, were the immediate source of the elements heavier than helium.
