A Tentative Expression of the Károlyházy Uncertainty of the Space-Time Structure Through Vacuum Spreads in Quantum Gravity

In the existing expositions of the Károlyházy model, quantum mechanical uncertainties are mimicked by classical spreads. It is shown how to express those uncertainties through entities of the future unified theory of general relativity and quantum theory.     

Causality Principle for a Reissner–Nordstrom Field in the RTG: The Small-Charge Case q2≤m2

We analyze the validity of the causality principle for the external electrovac solution generated by a static spherically symmetric and electrically charged body in the relativistic theory of gravity with a vanishing graviton mass, i.e., the Reissner–Nordstrom solution. We show that this principle restricts values of the constant in the external solution and also sets a lower bound for the source radius. We demonstrate that the external field of superdense star configurations satisfies the causality principle.     

Issue of the spherically symmetric static vacuum metric in the relativistic theory of gravity

The spherically symmetric vacuum metric in the relativistic theory of gravity is analyzed numerically. It is found that there is no deviation of the numerical solution from that of general relativity except in the near-horizon range. The solution obtained has the well-established analytical asymptotics for both the near-and far-horizon limits. It satisfies the causality principle and does not impose a lower limit on the graviton mass.      

The simplest black holes

A relativistic gravitational theory in (1 + 1) dimensions is presented which exhibits many of the qualitative features of (3 + 1)-dimensional general relativity. The field equations are simple enough for undergraduates to solve yet rich enough in structure to form a useful pedagogical example for exploring the qualitative features of relativistic gravitation. Black hole solutions to the field equations of the theory are derived and its relationship to Newtonian gravity is discussed in detail.     

A conformai,symmetry broken model for gravity

Starting from Padmanabhan's fully conformally invariant action, we obtain gravity as a spontaneously broken theory. Newton's constant and the cosmological constant follow from the breakdown of the conformal symmetry at the tree approximation. For small oscillation of the scalar field about the fundamental state, the matter field degenerates into two decoupled fields.     

Dual nature of Ricci scalar and creation of spinless particles

Manifestation of Ricci scalar like a matter field as well as a geometrical field, at high energy, has been noted earlier [9]. Here, its interaction with another scalar field is considered in four-dimensional curved space-time. This interaction leads to the production of a large number of pairs of spinless particle-antiparticle due to expansion of the early universe in the vacuum state (provided by temperature dependent Coleman-Weinberg like potential for Ricci field), where spontaneous symmetry breaking takes place.     

Melt-casting of Si-Al-Y-O glasses and glass-ceramics by combustion synthesis under high gravity

Si-Al-Y-O glasses and glass-ceramics were prepared via melt-casting by combustion synthesis under high gravity. The phase assemblage and microstructure of the cast products strongly depended on the content of SiO₂ and the additive ZrO₂ or La₂O₃ in the starting compositions. With increasing content of SiO₂, the glass-forming ability of the melt was enhanced. The additive ZrO₂ was not dissolved into the glass and inclined to crystallize, but La₂O₃ was inclined to remain in the glass matrix instead of precipitation. With a short processing period and lower energy consumption, combustion synthesis under high gravity can offer a new approach to fast fabrication of glass and glass-ceramic materials.     

热重分析技术研究聚-α-甲基苯乙烯降解温度

采用热重分析技术研究了4种聚-α-甲基苯乙烯原料和其它微球壳层材料的热降解温度。研究表明,聚-α-甲基苯乙烯原料主要失重温度范围为220～340℃,等离子体辉光放电涂层材料的降解温度为350～450℃。升温速率在20℃/min和30℃/min时,降解温度基本相同,升温速率不影响降解的温度范围,低于20℃/min时,随着升温速率升高,降解温度升高。     

再循环重力供液蒸发器管内换热性能预测

为了找出适用于再循环重力供液蒸发器管内强制对流沸腾换热系数的关系式,通过对以R404A为制冷剂的重力供液实验台的研究,编程计算出J.Chawla关系式及Shah关联式对重力供液沸腾换热系数进行预测值。与实验结果比较可知:J.Chawla关系式在较低温度下较接近于实验值,Shah关联式在较高的温度下可以对实验值进行预测,两种关系式相结合的方法就可以较好对重力供液蒸发器管内沸腾换热进行预测。     

LAMOST光纤单元定位参数研究

大天区多目标光纤光谱天文望远镜LAMOST是世界上光谱获取量最大的望远镜,4000个双回转光纤单元的精确定位是关键因素之一。根据对星像观测的要求以及单元的定位方式,确立了所需的7个定位参数,研究了在复杂现场环境下获取定位参数的具体流程和可行性算法,包括光重心法、摄像机快速标定算法、基于最小二乘拟合圆算法、空间坐标旋转算法等。通过模拟星像观测仿真测试和现场星像试观测证明,定位参数精度能很好地满足观测需求。目前LAMOST望远镜观测光谱获取率已达到90%以上。