Quantization of reimannian gravity: interaction representation

A Riemann-covariant expression of Schwinger's procedure, leading from a Heisenberg to an interaction representation, completes here our quantization of the coupling of a massive graviton field and a spin-zero Kemmer field.     

Critical mass of bacterial populations and critical temperature of self-gravitating Brownian particles in two dimensions

We show that the critical mass M_c=8π of bacterial populations in two dimensions in the chemotactic problem is the counterpart of the critical temperature T_c=GMm/4k_B of self-gravitating Brownian particles in two-dimensional gravity. We obtain these critical values by using the Virial theorem or by considering stationary solutions of the Keller-Segel model and Smoluchowski-Poisson system. We also consider the case of one-dimensional systems and develop the connection with the Burgers equation. Finally, we discuss the evolution of the system as a function of M or T in bounded and unbounded domains in dimensions d=1, 2 and 3 and show the specificities of each dimension. This paper aims to point out the numerous analogies between bacterial populations, self-gravitating Brownian particles and, occasionally, two-dimensional vortices.     

Maximal proper acceleration and the structure of spacetime

A limiting proper acceleration in nature follows deductively from known physics and compels the union of spacetime and four-velocity space into a maximal-acceleration invariant phase space having an intrinsic Kaluza-Klein-type fiber-bundle structure with manifest gauge properties. The Riemann curvature scalar of the bundle manifold is determined, and a possible action principle is considered to serve as a basis for the generation of field equations.1. This is an expanded version of an invited paper presented at the Fifth Marcel Grossmann Meeting at the University of Western Australia, 8–12 August 1988.     

Proof of perturbative gauge invariance for tree diagrams to all orders

It is proved that classical BRS‐invariance of the Lagrangian implies perturbative gauge invariance for tree diagrams to all orders. The proof applies in particular to the Einstein Hilbert Lagrangian of gravity.     

On the Water Depth in the Breach during a Partial Dam Break

Theoretical and experimental data which make it possible to find the flow-rate, momentum and energy of the fluid that enters the lower pool after a discontinuity breakdown (dam break) in a rectangular channel with an even bottom, a step (sharp downstream rise in the bottom), a shelf (sharp drop in the bottom), and a threshold on the bottom are presented.     

Charged AdS black holes with finite electrodynamics in 4D Einstein-Gauss-Bonnet gravity

Using a modified expression for the electric potential in the context of T-duality [Gaete and Nicolini, Phys. Lett. B, 2022], we obtained an exact charged solution within the 4D Einstein-Gauss-Bonnet (4D EGB) theory of gravity in the presence of a cosmological constant. We show that the solution also exists in the regularized 4D EGB theory. Moreover, we point out a correspondence between the black hole solution in the 4D EGB theory and the solution in the non-relativistic Horava–Lifshitz theory. The black hole solution is regular and free from singularity. As a special case, we derive a class of well known solutions in the literature.     

NORMAL EXPANSION THEORY FOR PENETRATION OF PROJECTILE AGAINST CONCRETE TARGET

Based on the equations which describe the dynamic behavior of material under high-velocity and high-pressure shock, corresponding equations at shock front whose surface is general space curve surface were established. For concrete material, a normal expansion theory was proposed by which some deceleration about time history of the projectile can be analytically given. This normal expansion theory is not only suitable for spherical and cylindrical-nose projectile, but also suitable for other general nose projectile, for example conical nose or ogive-nose. And it is not only suitable for perpendicular shock but also for oblique shock.     

平稳小波在高精度重力仪信号处理中的应用

为有效地消除噪声对重力仪测量数据的影响,提高重力异常测量值的精度,在分析平稳小波多尺度分析原理的基础上,将平稳小波应用到重力仪数据处理中,并与传统小波多尺度分析进行了对比.理论分析和仿真实验表明,平稳小波和传统小波都能在一定程度上抑制噪声对高精度重力仪测量数据的影响,但平稳小波的性能优于传统小波.     

优化设计理论在抗滑桩工程中的应用

采用数学规划方法中的直接最优化方法———复合形法,对已知荷载或内力的抗滑桩,以结构成本为目标函数进行满足工程使用要求的有约束最优化设计,编制了相应的程序,并用VisualBasic6 .0开发了应用程序界面,将优化以后所得结果与使用传统设计方法结果比较,有较大降低结构成本的效果。     

圆形重力式网箱锚碇系统的受力研究

依据Stokes二阶波浪理论和莫里森(Morison)方法,对圆形重力式网箱的浮架结构分别与工程上常用的两种锚碇系统(折线形与直线形)相结合情况下,锚碇系统的受力进行了数值计算及相应的物理模型试验。结果表明相同波况下折线形锚碇系统承受张力较小,在相同波浪周期条件下,波高越大锚碇点受力越大;相同波高下,锚碇点最大受力随周期变化不显著。将计算结果与模型试验对比,结果显示计算数值与试验数据较接近,表明了此计算方法的可行性,为进一步模拟浮架结构的运动变形打下基础。