A Number Theoretic Analysis of the Enthalpy, Enthalpy Energy Density, Thermodynamic Volume, and the Equation of State of a Modified White Hole, and the Implications to the Quantum Vacuum Spacetime, Matter Creation and the Planck Frequency

In this paper, we analyze the enthalpy, enthalpy energy density, thermodynamic volume, and the equation of state of a modified white hole. We obtain new possible mathematical connections with some sectors of Number Theory, Ramanujan Recurring Numbers, DN Constant and String Theory, that enable us to extract the quantum geometrical properties of these thermodynamic equations and the implication to the quantum vacuum spacetime geometry of our early universe as they act as the constraints to the nature of quantum gravity of the universe.

Gravity inversion using the frequency characteristics of the density distribution

Three-dimensional gravity inversion based on the mass property model is very popular in recent years. The time and efficiency of inversion algorithms is relative to the magnitude of the target mesh. One approach is to search over the entire solution space for a more refined result. However, the inversion will be difficult with the increased parameters in the large search space and the number of computations increases exponentially. ｜n this paper, we propose a novel approach based on the frequency characteristics of the density distribution over the mesh. The purposes of our study are to reduce the parameters of three- dimensional gravity inversion and to lighten the image quality of the inversion result. The results show that the new method can expedite the inversion processing and get a better geological interpretation than tradition methods.

3D density inversion of gravity gradiometry data with a multilevel hybrid parallel algorithm

The density inversion of gravity gradiometry data has attracted considerable attention;however,in large datasets,the multiplicity and low depth resolution as well as efficiency are constrained by time and computer memory requirements.To solve these problems,we improve the reweighting focusing inversion and probability tomography inversion with joint multiple tensors and prior information constraints,and assess the inversion results,computing efficiency,and dataset size.A Message Passing Interface(MPI)-Open Multi-Processing(OpenMP)-Computed Unified Device Architecture(CUDA)multilevel hybrid parallel inversion,named Hybrinv for short,is proposed.Using model and real data from the Vinton Dome,we confirm that Hybrinv can be used to compute the density distribution.For data size of 100×100×20,the hybrid parallel algorithm is fast and based on the run time and scalability we infer that it can be used to process the large-scale data.

Theoretical simulation of the effect of deformation on local gravity in a density gradient zone

We modeled the effect of the deformation of a Density Gradient Zone （DGZ） on a local gravity field using a cubical model and introduced a new method to simulate a complex DGZ （CDGZ）. Then, we analyzed the features of the model for the influence of the deformation of the DGZ on the local gravity field. We concluded that land-based gravity is not sensitive to the thickness of the DGZ and that the magnitude of the contribution of the DGZ is one order less than that of the volume strain with the same displacement.

Density structure of the crust in the Emeishan large igneous province revealed by the Lijiang-Guiyang gravity profile

The Emeishan large igneous province(hereafter named by its acronym ELIP) is the first accepted large igneous region in China.The current study tries to reconstruct the density structure of the crust in this region. For this purpose, we conducted the gravity survey along an 800-km-long profile, which stretched laterally along the latitude 27°N from Lijiang(Yunnan province) to Guiyang(Guizhou province). The fieldwork included 338 gravity measurements distributed from the inner zone to the outer zone of the mantle plume head.After a series of gravity reductions, we calculated the Bouguer gravity anomaly and then constructed the density model for ELIP by iterative forward modeling from an initial density model tightly constrained by wide-angle seismic reflection data. The topography of the Moho, here physically interpreted as a density discontinuity of ~0.4 g·cm^(–3), gradually rises from the inner zone(~50 km deep) to the outer zone(~40 km), describes a thicker crust in the inner zone than in any other segment of the profile and largely reproduces the shape of the Bouguer gravity anomaly curve. Both the Bouguer gravity and the density structure show significant differences with respect to the inner zone and the other two zones of ELIP according to the commonly accepted partition of the Emeishan area. A thicker and denser middle-lower crust seems to be the main feature of the western section of the profile, which is likely related to its mafic magmatic composition due to magmatic underplating of the Permian mantle plume.

Effi cient modeling of the gravity anomaly caused by a sedimentary basin with lateral variable density contrast and its application in basement relief estimation

The forward calculation of gravity anomalies is a non-negligible aspect contributing to the time consumption of the entire process of basement relief estimation.In this study,we develop a fast hybrid computing scheme to compute the gravity anomaly of a basement.We use the vertical prism source equation in a given region R centered at a certain gravity observation point and the vertical line source equation outside R to derive the gravity anomaly.We observe that the computation with the vertical line source equation is much faster than that of the vertical prism source equation,but the former is slightly inaccurate.Therefore,our method is highly effi cient and able to avoid the errors caused by the low accuracy of the vertical line source equation near the observation point.We then derive the general principle of choosing the size of R via a series of prism model tests.Our tests on the gravity anomaly over the Los Angeles Basin confirm the correctness of our proposed forward strategy.We modify Bott’s method with an accelerating factor to expedite the inversion procedure and presume that the density contrast between the sediments and the basement in a sedimentary basin varies laterally and can be obtained using the equivalent equation.Synthetic data and real data applications in the Weihe Basin illustrate that our proposed method can accurately and effi ciently estimate the basement relief of sedimentary basins.

Theoretical study on separation density of gravity beneficiation

Separation density is one of the most concerned operating parameters in gravity beneficiation.Although equal-errors cut point or distribution density is usually used as practical separation density in gravity beneficiation, the gravity separating process complexly affected by many kinds of factors is actually carried out at a fluctuant density; namely, the practical separation density is essentially a random variable.The studied results show that the equal-errors cut point is the mathematical expectation of this random variable, and the distribution density corresponds to the highest separation efficiency in the gravity separation process.This shows that the distribution density is the best working point of the gravity separation equipment under a particular operating condition.Therefore,in order to fully develop the function of the gravity separation equipment, the distribution density should be close to the theoretical separation density unlimitedly in the range of minimum fluctuation.

Gravity effect calculation of threedimensional linear density distribution andits application

An algorithm for calculating gravity effect of three-dimensional (3D) linear density distribution is presented in this paper. The linear continuous density distribution is represented with 3D grid model, which has a resemblance to the velocity model used in some seismic tomography codes. The consensus in representation method of density model and velocity model facilitates the seismic-gravity-integrated interpretation or simultaneous inversion. The numerical test of synthetic data shows that although the analytical gravity formula for linear density distribution is more complex than that for piecewise constant density distribution, it takes less time to calculate the gravity effect with linear density model than that with piecewise constant density model. In addition, this method is used in the integrated interpretation of 3D seismological tomography and gravity data in Dabie Mountain area.

Energy-Momentum Density of Non-Diagonal Bianchi Type Space-Time in General Relativity and Teleparallel Gravity

We calculated the energy-momentum density of non-diagonal Bianchi type space-time in two different theories of gravity, General relativity (GR) and the theory of Teleparallel gravity (TG). Firstly, by applying Einstein, Landau-Lifshitz, Bergmann-Thomson and Møller prescriptions, using double index complexes in GR. Secondly, in the frame work of TG, we used the energy momentum complexes of Einstein, Bergmann-Thomson and Landau-Lifshitz. We also study the spacial cases of non-diagonal Bianchi type space-time BII, BVIII and BIX. We obtained the same energy-momentum density components for Einstein and Bergmann-Thomson prescriptions for the above four mentioned space-times that we considered in our work. Also, we found that the energy density component in Møller prescription is zero for all Bianchi types space-times in GR. Furthermore, we show that if the metric components are functions of time t alone, then the total gravitational energy is identically zero.

Density Structure of the Papua New Guinea-Solomon Arc Subduction System

The Papua New Guinea-Solomon(PN-SL)arc is one of the regions with active crustal motions and strong geological actions.Thus,its complex subduction system makes it an ideal laboratory for studying the initiation mechanism of plate subduction.However,the PN-SL subduction system has not yet been sufficiently studied,and its density structure has yet to be revealed.In this paper,we used the free-air gravity data,Parker-Oldenburg density surface inversion method,and the genetic algorithm density inversion method to obtain the density structure of an approximately 1000-km-long northwest-southeast line crossing the PN-SL subduction system under the constraints of the CRUST1.0 global crustal model,onshore seismic data,and the LLNL-G3Dv3 global P-wave velocity model.The density structure shows that density differences between the plates on the two sides of the trench could play a significant role in plate subduction.

Implications on Gravity Anomaly Measurements Associated with Different Lithologies in Turkana South Subcounty

The use of gravity data has demonstrated capability for monitoring lithological changes on a large scale as a consequence of differentiating basement and sedimentary of buried valleys. Gravity anomalies are associated with lateral contrasts in density and therefore deformation by faulting or folding will be manifested if accompanied by lateral density changes, otherwise, the vice versa is true. The study’s objective is to evaluate the effectiveness of gravity method in establishing different lithologies in an area. The study has revealed that regional anomaly gravity map presents high anomalies in the Northern region in the NW-SE trend and low anomalies in the southern trend in NW-SE, while the residual anomaly gravity map shows different trends for the low and high gravity anomalies. The gravity anomalies are well interpreted in line with the lithologies of the study area rather than the deformation of the same lithologies. There are observed high values of gravity anomaly values (ranging from -880.2 to -501.2 g.u.) where there are eolian unconsolidated rocks overlying the basement compared to low gravity anomaly values (ranging from -1338.9 to -1088.7 g.u.) where the andesites, trachytes and phonolites overly the basement. The different regional gravity anomalies relate well with different rock densities in the study area along the line profile for radially averaged power spectrum. The gravity highs are noted in the eastern point and are associated with andesites, trachytes, basalts and igneous rocks, while the gravity lows are associated with sandstone, greywacke, arkose, and eolian unconsolidated rock. The utilization of the information from the Power spectrum analysis demonstrates that the depth to the deepest basement rock is 12.8 km which is in the eastern flank, while the shallowest to the basement of 1.1 km to the western flank.

华南陆块西南缘上地幔顶部三维密度结构及其地质意义

华南陆块自新远古代拼合以来,经历了多期构造-岩浆活动,岩石圈及其深部结构较为复杂,前人对西南缘扬子与华夏地块缝合带位置的厘定仍有不同认识.研究该区域上地幔顶部密度结构,有助于进一步认识扬子—华夏地块拼合对岩石圈的改造,对确定扬子—华夏地块在广西地区的边界位置有重要意义.基于卫星布格重力异常,利用地震波速度-密度转换关系构建的上地幔密度参考模型作为约束,反演剩余的岩石圈和上地幔重力异常,获得了岩石圈至300 km深度的上地幔顶部三维密度结构.密度结构揭示了华南陆块西南部的岩石圈—软流圈界面起伏和上地幔物质密度的不均匀分布.分析结果表明广西中部存在高密度岩石圈物质下沉,南部低密度的软流圈物质上涌,取代已拆沉的岩石圈根并向上侵入地壳,是地表出露花岗岩的来源.结合区内基底特征和碎屑锆石陆缘来源,推断沿广西富川—武宣—隆安—凭祥一线为扬子—华夏地块在华南陆块西南缘(广西段)缝合位置.

下辽河平原区耕地非农化时空演变特征及驱动机制

探索耕地非农化的时空演变特征及其驱动机制是耕地保护的前提,分析下辽河平原区2000—2020年耕地非农化的时空演变特征及驱动机制,可以为该地区耕地保护政策的制定与防止耕地非农化提供理论依据。本文基于2000年、2005年、2010年、2015年和2020年5个时期的土地利用数据,以下辽河平原区为研究区域,结合社会经济数据,运用ArcGIS 10.2空间叠加分析,计算耕地非农化面积,采用重心迁移模型、核密度分析、地理探测器等统计学和地理信息系统的空间分析方法,揭示下辽河平原区耕地非农化特征及其演变趋势,并探讨其耕地非农化的驱动因素。研究结果表明:1)在时间上,下辽河平原区耕地非农化面积和非农化率呈现周期性波动,耕地非农化总面积为2201.52 km^(2),耕地非农化率为7.11%。2)在空间分布上,耕地非农化的重心主要从辽中区向东北方向迁移至于洪区,下辽河平原区耕地非农化东部地区高于西部地区,核密度最大值1657.3,主要在于洪区、浑南区、沈北新区、苏家屯区附近;耕地非农化的次集中区域为新民市和昌图县,其核密度最大值分别为1033.18和1018.49。3)在驱动因素上,耕地非农化驱动因素影响依次为农业机械总动力>户籍人口>城镇人口>固定资产投资>第三产业增加值>GDP>粮食产量>第二产业增加值,交互作用探测器表现为双因子增强或非线性增强关系。综合来看,耕地非农化是社会、经济因素综合作用的复杂结果。鉴于此,本文建议通过严格控制城市建设用地占用耕地的规模、挖掘农村居民点利用潜力、转变经济发展方式、推动农业产业结构调整等措施治理耕地非农化。

秋冬季温度降低对微囊藻衰亡和沉降的作用机制

为明确温度降低对微囊藻衰亡和沉降的影响,对贡湖微囊藻水华的消退过程进行了监测,同时开展了室内低温培养试验。结果表明:室内试验模拟结果与野外秋冬季的现象基本吻合,微囊藻一般在温度低于15℃时衰亡,低于12.5℃大量沉降;温度降低造成群体粒径显著减小,与群体内死亡的藻细胞数量有关,当死亡率达到25%~45%时,大群体普遍开始解体并分散成小群体;微囊藻在低温下重力密度持续增长,最终失去自主上浮能力;秋冬季降温初期微囊藻沉降主要由群体小型化和松散化导致,重力密度增大很可能是降温后期微囊藻沉降的主要原因。

胶东地区重磁场特征及地质解释

本文系统统计了山东胶东地区各地层、岩浆岩的磁化率、剩余磁化强度及密度等物性参数特征,从地质、物性两个角度对区域重磁场特征进行了综合分析。研究结果表明:重、磁场总体走向呈NE—NNE,宏观上反映了胶东地区的地层分布、构造格架和岩浆活动;重力场强度变化较大,跨越(-40~40)×10^(-5)m/s^(2)区间,在胶莱盆地南北两侧表现为重力低,盆地内则反映为重力高;磁场以低缓磁场为主,北、中部场强低、变化小,东南部场强高、变化大。胶东地区重磁场特征反映了该区南部、北部岩浆活动较强烈,中部壳层变薄,基底构造以近EW向、局部构造呈NE向,以及较高密度、较强磁性的古老结晶基底呈带、呈块分布的总体格局。

基于UNet++卷积神经网络的重力异常三维密度反演

三维密度反演是地球物理领域的研究热点,而在大数据及人工智能发展的时代背景下如何快速高效地实现重力数据反演显得更为重要.传统反演方法通常需要存储大型系数矩阵,内存占用大,耗费时间长,同时为约束反演结果而加入的正则化约束项参数难以确定;深度学习可以不依赖先验信息,也不需要计算及存储系数矩阵,使得计算效率大大提高.基于此,本文提出了一种基于UNet++网络的重力异常反演方法.首先将UNet++网络中部分参数进行更改:选择在输入数据绝对值较大时梯度更稳定的LeakyReLU作为激活函数;加入了Batch Normalization层,增强了网络的收敛速度及稳定性.然后为了提高网络的全局最优化能力,引入了基于余弦退火的学习率更新策略,使用梯度的一阶以及二阶矩估计的Adam最优化算法,利用数据集与标签集进行网络训练,实现了重力异常的三维密度反演.通过实验验证了UNet++、LeakyReLU更快速稳定的收敛能力,而余弦退火学习率更新策略具有更强的全局寻优能力.含噪模型实验及实际数据反演结果进一步证明该方法的正确性和有效性,及其良好的泛化能力与抗噪能力.

蓟县地震台gPhone、DZW和GS-15重力仪重力噪声水平对比

选取蓟县地震台同址观测的3台不同型号重力仪(gPhone、DZW和GS-15)2022年全年的连续观测数据,研究不同类型仪器对环境噪声的响应,计算3种重力仪的重力噪声水平,同时计算地震频段(200~600 s)的地震噪声等级,并与全国gPhone重力仪的地震噪声等级进行对比。结果表明:1)在频率低于10-3 Hz时,扣除固体潮和气压改正可以明显改进重力噪声水平;2)相同台站不同仪器重力噪声水平不同,gPhone型重力仪的背景噪声水平低于DZW型重力仪和GS-15型重力仪,其SNM值为3.355;3)2022年全国gPhone重力仪的地震频段噪声水平均值为5.418,蓟县台的噪声水平平均值为3.465,低于全国的噪声水平。研究结果可为3类重力仪观测数据的研究应用提供参考。

一种基于谱分析的重力场统计特征建模方法

重力场的统计特征主要包括协方差(相关函数)、功率谱密度、球谐阶方差等参量,是从空域、频域和球谐域描述重力场变化规律的主要依据.本文以扰动位的距离倒数协方差模型为核函数,研究了一种能在不同重力场元之间自洽解析转换的统计特征建模方法.分别利用高分辨率的地面重力异常和实测航空重力梯度数据进行功率谱分析,结合EGM2008模型构建了3组重力场统计特征模型,分析了本文模型与经典模型的差异,并用于高频重力场随机模拟,验证了本文方法在不同频率区间建模的可行性和实用性.本文模型可用于重力梯度探测、高频重力场随机模拟、重力场推估等方面的定量分析,相关算法和思路也可为构建更精细的统计特征模型提供借鉴.

重力数据探测地下目标的贝叶斯方法研究

针对地下目标空间位置和形状均未知的情况,基于重力数据,分别以区域测量和线测量2种场景进行建模分析,研究贝叶斯推断用于地下目标探测的效果。结果表明,将贝叶斯推断用于重力梯度探测,比微重力探测更具优势,能有效反演出目标的未知参数。

类地行星低阶重力场、自转与内部圈层结构研究进展

低阶重力场和自转参数是类地行星内部结构的函数且指示着其物质成分与演化,一直是深空探测的首要目标.行星自转状态能够直接揭示行星核的密度和大小.随着深空探测数据的逐渐积累和精度的不断提高,低阶重力场和自转观测在行星内部结构,尤其是行星核方面的研究取得了一系列重要进展.本文首先介绍行星主惯性矩张量的基本理论与计算方法,接着介绍行星自转动力学基本理论以及与行星内部结构密切相关的行星自转简正模,并介绍利用低阶重力位系数求解行星主惯性矩张量的方法.本文还总结了利用有限的自转观测和低阶重力场观测确定行星平均密度和平均惯性矩的研究现状,以及反演行星内部结构的基本方法.最后,本文对目前利用低阶重力场、自转观测反演行星和小行星等内部结构方面存在的问题进行了总结与展望,希望为我国未来的深空探测计划提供科学参考与理论支持.