Anomalous Characteristics Research Articles

Electrical conductivity of copper in the low temperature region of warm dense matter

In this study, electrical conductivity of copper in the low temperature part of a warm dense matter regime is investigated utilizing underwater electrical wire explosion. Specifically, for the vapor/plasma region with a density of ∼0.01 normal density, temperature up to 10 kK, and the liquid–vapor two-phase region below the binodal curve, the electrical conductivity of copper is measured as a function of density and temperature by means of shadowgraph imaging, spectroscopy, and electrical measurements. In this region, anomalous temperature dependence and characteristics originated from a phase transition are found. Based on the careful analysis of experiments and model calculations, it is revealed that bound electrons, in addition to free electrons, contribute significantly to the electrical conductivity in the vapor/plasma region, and that the associated phase transition kinetics play a substantial role in adequately describing the behavior in the liquid–vapor two-phase region. An improved electrical conductivity model emerging from our combined experimental and theoretical study that accounts for the characteristics in the low temperature regime of the warm dense matter is presented.

Electromagnetic characteristics analysis of dual-frequency magnetic single negative metamaterials

Abstract With the development of multi-frequency wireless transmission technology, it is necessary to expand the research of single-frequency metamaterials in the multi-frequency field. The dual-frequency metamaterial studied adopts a nested square spiral structure, which can resonate at two frequencies, and the real part of the equivalent permeability of metamaterial changes dramatically at the resonance frequency, and the equivalent electromagnetic parameter exhibits anomalous characteristics in the two frequency bands. Firstly, the effects of the number of turns, the width of the copper wire, the spacing of the copper wire, and the length of the outermost edge of inner and outer helical coils are investigated, respectively, using the HFSS software on the resonance frequency of dual-frequency metamaterials, which improves the study of dual-frequency metamaterials with nested square spiral structure. Then, based on the results of the change rule of resonance frequency with the four types of influencing factors, the dual-frequency metamaterials with the real part of the equivalent permeability close to -1 at 6.78 MHz and 13.56 MHz are designed, which is of certain reference significance for the subsequent practical design of dual-frequency metamaterials to satisfy the needs of the project.

Anomalous Characteristics of Water Vapor Budget on the Tibetan Plateau under the Influence of Tropical Cyclones over the Bay of Bengal during Early Summer

Abstract Early summer is a peak time for tropical cyclone (TC) activities over the Bay of Bengal (BoB) and a period of South Asian monsoon onset, and the TCs during this time have a significant impact on the water vapor transport associated with monsoons. This study investigates the anomalous characteristics of the dynamic–thermal atmospheric circulation structure and water vapor budget over the Tibetan Plateau (TP) under the influence of BoB TCs generated in May from 1979 to 2020 with JTWC best track data and ERA5 data. Results reveal that a significant southerly water vapor channel forms from the BoB to the southeastern TP with a water vapor convergence near the Yarlung Zangbo Grand Canyon. A part of the water vapor is transported directly to the TP by deep southerly jet, while the other part is lifted by TCs and then climbs upward to the TP by two uplift processes occurring on the southern slope of the TP and over the TP respectively, which makes the whole troposphere over the southeastern TP warmer and wetter. It is found that anomalous southeasterly airflow in the northeast of TC circulation turns to anomalous southwesterly airflow forming an abnormal anticyclonic circulation over the southern TP in the middle and upper troposphere due to the diabatic heating effect. In this process, the TP acts as an anomalous water vapor sink with remarkable water vapor inflow through its southern boundary, with the main water vapor outflow through the eastern boundary, but a weak easterly water vapor backflow to the eastern TP in the lower troposphere. Significance Statement This study attempts to investigate the anomalous features of the water vapor budget over the Tibetan Plateau (TP) under the influence of the Bay of Bengal (BoB) tropical cyclones (TCs) during early summer. Results show that a significant southerly water vapor channel forms from the BoB to the southeastern TP with a water vapor convergence near the Yarlung Zangbo Grand Canyon. The TP acts as an anomalous water vapor sink with more and higher water vapor inflows through the southern boundary of the TP. A positive temperature and humidity anomaly can be found over the southeastern TP extending upward into the middle and upper troposphere. The results are helpful to understand how the BoB TCs affect the weather process over the TP.

In-plane elastic waves in piezoelectric metamaterials with Parity–Time symmetry

The propagation of in-plane waves in piezoelectric metamaterials involves the coupling of longitudinal (i.e. quasi–pressure), transverse (i.e. quasi–shear) and electric potential waves, which can result in different exotic phenomena. In this study, the stiffness matrix method is used to analyze the dispersion relation, which contains anomalous propagation characteristics. With the coupling of electric potential, the frequency spectrum of in–plane wave shows new characteristics. The exceptional point caused by non–Hermitian operator that does not exist before also appears when the vertical wave number is imaginary. The oblique incidence of the in–plane wave at the interface between a homogeneous medium and phononic crystal can excite multiple refraction modes which include the negative refraction. The normal mode decomposition is developed to study the in-plane incidence of piezoelectric metamaterial and then the averaged Poynting vector is applied to obtain the refraction angle. Moreover, the defect layer is introduced into the phononic crystals to study the transmission coefficients with two different symmetrical arrangements. When the balanced gain and loss are considered in the metamaterial, the Parity–Time symmetry appears and brings in pairs of exceptional points to achieve complete transmission with unidirectional zero reflection.

On-Chip Fabrication-Tolerant Exceptional Points Based on Dual-Scatterer Engineering.

The intriguing and anomalous optical characteristics of exceptional points (EPs) in optical resonators have attracted significant attention. While EP-related phenomena have been observed by perturbing resonators with off-chip components, implementing EPs fully on-chip remains challenging due to their extreme susceptibility to fabrication errors. In this Letter, we propose a succinct and compact approach to reach EP in an on-chip integrated silicon microring resonator by manipulating the evolution of backscatterings with two nanocylinders of disparate diameters. The theoretical analysis unveils that the fabrication constraints could be significantly relieved by increasing the difference in diameters of the nanocylinders. The evolution from non-EP to EP is traced experimentally through the step-by-step tuning of the angular and radial positions of nanocylinders. The proposed method opens a pathway toward the on-chip high-density integration of non-Hermitian devices.

Mechanical properties and failure modes of additively-manufactured chiral metamaterials based on Euclidean tessellations: an experimental and finite element study

PurposeThe “chiralisation” of Euclidean polygonal tessellations is a novel, recent method which has been used to design new auxetic metamaterials with complex topologies and improved geometric versatility over traditional chiral honeycombs. This paper aims to design and manufacture chiral honeycombs representative of four distinct classes of 2D Euclidean tessellations with hexagonal rotational symmetry using fused-deposition additive manufacturing and experimentally analysed the mechanical properties and failure modes of these metamaterials.Design/methodology/approachFinite Element simulations were also used to study the high-strain compressive performance of these systems under both periodic boundary conditions and realistic, finite conditions. Experimental uniaxial compressive loading tests were applied to additively manufactured prototypes and digital image correlation was used to measure the Poisson’s ratio and analyse the deformation behaviour of these systems.FindingsThe results obtained demonstrate that these systems have the ability to exhibit a wide range of Poisson’s ratios (positive, quasi-zero and negative values) and stiffnesses as well as unusual failure modes characterised by a sequential layer-by-layer collapse of specific, non-adjacent ligaments. These findings provide useful insights on the mechanical properties and deformation behaviours of this new class of metamaterials and indicate that these chiral honeycombs could potentially possess anomalous characteristics which are not commonly found in traditional chiral metamaterials based on regular monohedral tilings.Originality/valueTo the best of the authors’ knowledge, the authors have analysed for the first time the high strain behaviour and failure modes of chiral metamaterials based on Euclidean multi-polygonal tessellations.

Anomalous Characteristics of Surface Geochemistry Above the Basin Geothermal System: A Case Study of the Shiba Basin in Huizhou, China

As one of the comprehensive exploration techniques for underground geological resources, surface geochemical methods could play an important role in geothermal exploration, which requires detailed and systematic investigations. In this study, we take the Shiba geothermal basin in Huizhou, China, as the research object and apply surface geochemical testing methods to analyze the intrinsic relationship between the geothermal system and the surface soil. The contents of soil gases and elements are mainly determined, among which hydrogen (H2) and radon (Rn) show three obvious negative anomalies, corresponding to three positive anomalies of soil elements (Fe, U, Cr, V, Cu, and As) that are easy to migrate. The largest negative and positive anomalies correspond to the surface above the fault, which is related to the dominant channel from underground to the surface and is caused by the gas loss effect and the dissolution and migration of inorganic ions. However, the effects of the surface environment and organisms cannot be ignored. Only when the geothermal system has a significant impact on a certain geochemical parameter could the anomaly be manifested in the surface soil. Otherwise, most of the geothermal information, including thermal conduction, will be covered by surface factors. After surface geochemical anomalies related to the geothermal system have been identified, anomaly patterns (especially the top anomaly pattern) can be preliminarily established, which can be used for geothermal exploration. Furthermore, based on the empirical regional geothermal formula, the temperature and depth of the Shiba geothermal system are evaluated at 170°C and 4500 m, respectively, indicating that surface geochemical methods have a good practical prospect in the prediction of geothermal resources.

Geochemical characteristics and genesis of the Ordovician sub-salt natural gas in the Ordos Basin, China

A significant amount of natural gas resources has been discovered in the Ordovician reservoirs under a thick layer of gypsum-salt strata as a result of ongoing research into deep natural gas in China’s Ordos Basin, however, the genetic type and source of the Ordovician sub-salt natural gas remain contentious. These limits understanding how the geochemical properties of the natural gas in Ordos Basin have evolved and how to best guide future exploration and development. Based on the components, carbon and hydrogen isotopic ratios of natural gas from the latest exploration wells, combined with the geological background, this study systematically analyzed the genetic types and sources of sub-salt natural gas of the central and eastern Ordos Basin. The results show that the Ordovician natural gas is mainly composed of hydrocarbon gases with low content of heavy hydrocarbons and dryness (CCH4/CCH4+) above 0.95, belonging to typical dry gas. Non-hydrocarbon gases mainly include N2 and CO2, and some natural gas samples contained H2S. The Ordovician sub-salt natural gas is primarily a self-generating and self-preserving oil-cracking gas with relatively high maturity (Ro ranging from 1.5% to 2.1%) mixed with coal-derived gas generated from upper-Paleozoic coal with relatively low maturity (Ro ranging from 1.1% to 1.5%). Due to the dual-source hydrocarbon supply, the Ordovician sub-salt reservoirs provide favorable gas accumulation conditions and development prospects. This study offers a reasonable explanation for the anomalous geochemical characteristics of the Ordovician sub-salt reservoirs in the Ordos Basin, and also may serve as a guide for future exploration of natural gas in the carbonate gypsum-salt sedimentary system in other basins.

Narrow-angle privacy protection based on anomalous propagation characteristics at epsilon-near-zero threshold frequency of YaBa2Cu3O7 ceramic material

In this paper, an optical privacy protection (OPP) device suitable for the TM wave by taking advantage of the anomalous propagation characteristics (APC) at epsilon-near-zero threshold frequency (ETF) of YaBa2Cu3O7 ceramic material coupled with the anti-reflection structure (AFS) is proposed. The APC at ETF can be used to provide angular transparency windows with highly selective properties in both the frequency and angle domains, while the AFS facilitates improving transmittance. Considering the limitation of temperature regulation, to control the size of the transmission window within a narrow range, prisms are introduced as the background medium. It is displayed that the proposed structure has a transmittance of more than 93 % in the region of −30°–30°, while the transmittance is close to 0 beyond −40° or 40°. The OPP covers 405–790 THz, involving the entire visible light region, and has a rectangle coefficient consistently exceeding 0.97. Taking the current process error into consideration, the thickness errors of ±5 % exert little effect on the result.

GaN vortex metasurface for interference and broadband characteristics.

We experimentally demonstrate a highly efficient metasurface-based optical vortex beam (OVB) composed of high-aspect-ratio gallium nitride (GaN) meta-structures with an exceptional simulated absolute polarization conversion efficiency (APCE) of up to 98%. A flower-like interference pattern emerges at the converging distance of the device with the helicity switching in spiral and dislocation interference patterns beyond this point, as confirmed through meticulous Mach-Zehnder interferometer analysis. The device also performs broadband capabilities across visible wavelengths. Experimentally demonstrated, the annular shape adeptly expands its diameter with increasing incident wavelengths. This phenomenon is rooted in the fascinating anomalous refractive and reflective characteristics inherent to subwavelength-period metasurfaces.

Vapor Phase Electrochemistry: The Missing Science

Several aspects of physics have been adversely effected by the fact that vapor phase electrochemistry has proved impossible to quantify. By the end of the 19th century, physicists had encountered several strange observations that appeared to involve chemistry. Eventually, it was realized that, in a moist gas, no rate process involving ions is quantifiable since we possess no valid relationship between the concentrations of electrolytes and their thermodynamic activities. There are both technical and societal reasons for this problem. Until both problems have been addressed, no reliable quantitative conclusions can be drawn for any system where ionic electrostriction in a moist gas is important. The most obvious consequences of the missing science are misconceptions concerning naturally contained air plasmas such as ball lightning, tornadic lights, and unpredictable flying objects (UFOs). None of these phenomena violates any known law of physics, but this only becomes clear once the absence of applicable, strictly valid theories is accepted. Fortunately, partial solutions to the problem exist if use is made of qualitative arguments. Using this approach, it can be seen that all the apparently anomalous characteristics of atmospheric plasmas result from a balance between different physical and chemical driving forces. A better understanding of the chemical consequences of electrostriction should have two long-term benefits. One relates to understanding the corrosive properties of high-pressure steam. The other concerns the specific chemical processes that stabilize air plasmas. If stable air plasmas could be simulated, a plentiful supply of carbon-free energy would become available.

A 2D elastic wall model to analyze the hyper‐viscous effects on blood flow across abdominal aortic aneurysm in COVID patients by fluid–structure interaction technique with ALE formulation

The worldwide dissemination of the coronavirus, as well as its dependencies, is being aided by detrimental urbanization. The impact of the viral infection upon an infected person is also thought to be influenced by any pre‐existing medical issues. Recent investigations have demonstrated that COVID‐19 patients have a higher degree of blood viscosity as a result of alterations in morphology in blood cells. Examining the importance of hyper‐viscosity in patients with COVID is crucial in determining the diseases of the arteries since viscosity is a key flow characteristic that affects the flow across a stenosis as well as an aneurysm. In the current study, a patient‐specific instance with an aneurysm across the abdominal aortal walls was taken into consideration. Given that abdominal aneurysms occur frequently in people, the high viscosity values are taken into account while examining the hyper‐viscous impact of fluid on its passage through the affected aorta. The current study is the initial endeavor to use the Arbitrary Lagrangian–Eulerian (ALE) Technique to study the impact of fluid–structure interaction (FSI) on the movement of fluid across an aneurysmal aortal section in conjunction with hyper‐viscous anomalous blood characteristics. The investigation backs up the different medical results that described the negative consequences of blood hyper‐viscosity. The computational findings from employing a finite element method (FEM) solver to resolve the fluid mechanical computations complemented alongside the solid mechanical principles indicate a possibility that the increased stress imposed by the hyper‐viscous propagates on the interior walls of the aneurysmal aorta may prompt the aneurysmal pouch to grow or breakdown. Also, the hyper‐viscous blood in COVID patients destroys the smooth muscle cells of the media layer endangering its normal structure and functions and leading to the development of new aneurysms.

The effects of relative position of anomalous body and topography on the semi-airborne transient electromagnetic survey

The semi-airborne transient electromagnetic method using short-offset has the characteristics of high signal-to-noise ratio and large detection depth, which can adapt to environmental monitoring, groundwater mapping and metal survey in complex terrain. The terrain effects will modulate semi-airborne transient electromagnetic method response. Most terrains effects studies assume that the anomalous body is located below the centre of topography or under the slope, however, in the direction of electromagnetic propagation, several scenarios exist regarding the position of an anomalous body relative to a topography, and different situations will have different anomalous characteristics. In this study, the time-domain finite-element modelling using unstructured mesh is used to investigate the distribution of the electromagnetic response of different time channels of different anomalous bodies in different positions relative to a topography under two conditions: mountains and valleys. The results show that (1) The influence of the relative position of the anomalous body and the topography is similar in the mountain and valley. When the anomalous body is located on the side of the topography far from the transmitter, it is more affected by the topography than when the anomalous body is located on the side of the topography near the transmitter, and (2) in the early stage, the distribution of the electromagnetic response is primarily determined by the topography, in the middle stage, the coupling between anomalous bodies at different locations and the topography results in an extremely complex response distribution, in the late stage, the response distribution primarily originates from the eddy current of the anomalous body, and the effect of the topography is moderate. When using semi-airborne transient electromagnetic method for environmental monitoring and shallow resources survey in complex terrain, data processing and interpretation should be performed based on the position of the anomalous body relative to the topography.

Anomalous stable hydrogen-oxygen isotope characteristics and water vapor sources of autumn precipitation in the Weihe River basin, Northwest China.

The extreme changes in autumn rain have significant impacts on the ecological environment of Weihe River basin. Based on 117 autumn rain samples and corresponding meteorological data from 2015 to 2021 at Yangling located in the middle of Weihe River basin, we investigated the stable hydrogen and oxygen isotope composition and water vapor sources of precipitation. The results showed that, (1) extreme changes in autumn rainfall in the study area occurred frequently in recent years, which could be divided into extreme-high autumn precipitation year (HAP, 2021), general autumn precipitation year (GAP, 2015-2017, 2019-2020) and extreme-low autumn precipitation year (LAP, 2018) based on the autumn rain index (ARI); (2) the stable isotopes of different types of precipitation differed significantly, with a pattern of LAP>GAP>HAP for both δ2H and δ18O values. the variations of d-excess values and the slopes and intercepts of the meteoric water lines of autumn rain showed opposite trends. The main factor controlling autumn rain anomaly was not the local meteorological parameters, but the El Nino-Southern Oscillation and the Indian Ocean dipole events, which could explain 99% and 93% of the autumn rain isotopic variations, respectively. These coupling phenomena affected water vapor transport intensity of the marine air mass to the northwest inland, which determined autumn rainfall amount and the stable hydrogen-oxygen isotope composition. Our results would be helpful for improving the understanding of autumn rain anomalies in West China, and provide basic data and theoretical support for regional hydrological model building, would thereby better serve water resources management and disaster prevention and reduction.

Study on co-seismic ionospheric disturbance of Alaska earthquake on July 29, 2021 based on GPS TEC

With the rapid development of space geodetic information technology, the Global Positioning System (GPS) has been widely used in seismology and space environmental research. Typically, the occurrence of a large earthquake will lead to some changes in the ionosphere, this phenomenon is called coseismic ionospheric disturbances (CIDs). In this contribution, differential slant total electron content (dSTEC) is used to study the anomalous characteristics of the ionosphere. First, based on the ionospheric dSTEC time series and two-dimensional disturbance detection, the temporal and spatial characteristics of ionospheric disturbances can be accurately analysed. Secondly, using wavelet transform spectrum analysis and disturbance propagation velocity, it can be determined that the disturbance sources of this earthquake can be identified as acoustic wave, gravity wave and Rayleigh wave. Finally, in order to further clarify the direction of the earthquake disturbance, this study focuses on proposing an innovative method for the disturbance propagation direction, and determines that there are two directions of the propagation of the CIDs of the Alaski earthquake.

Extreme Summer Precipitation Characteristics and Associated Water Vapor Transport in Southern Xinjiang

In this study, we analyzed the spatial and temporal characteristics of extreme precipitation in summer in southern Xinjiang (SXJ) using CN05.1 daily precipitation data, the National Centers for Environmental Prediction (NCEP) monthly average data, and ERA5 four-times-daily reanalysis data from 1961 to 2020, determined the interdecadal variation in extreme precipitation, and further explored the circulation mechanisms and anomalous water vapor transport characteristics associated with changes in extreme precipitation. The results showed that extreme precipitation, extreme precipitation days, and extreme precipitation contribution in SXJ all increased significantly, with the turnaround occurring in 1986. Enhanced vertical upward motion, greater convergence of water vapor at lower levels, and a more unstable atmospheric convection led to an increase in extreme precipitation along the southern border region. The eastward Pacific Ocean and southward Indian Ocean provided anomalous water vapor transport, and the boundary water vapor flux trend and its correlated distribution with extreme precipitation showed that southern boundary water vapor transport played an important role in the increase in extreme precipitation. At vertical heights, the dominant longitudinal water vapor transport fluxes were concentrated in the middle and upper layers, whereas the latitudinal water vapor transport fluxes were concentrated in the middle and lower layers.

Comment: A Solution to the Pioneer Anomalous Annual and Diurnal Residuals by E. D. Greaves, et al., 2021 Progress in Physics, vol. 17, 2, p. 168

A comparison is made between Greaves, E. D., Bracho, C., Gift, S., and Rodrigues, A. N., 2021. A Solution to the Pioneer Anomalous Annual and Diurnal Residuals, Progress in Physics, vol. 17, 2, p. 168. and Hodge, J. C. 2006. Scalar potential model of the Pioneer Anomaly.arXiv: astro-ph/0612567v1. Both papers suggest the Pioneer Anomaly obser- vation is due to the signal being modified by a characteristic of space that is influenced by the Sun and Earth. The papers differ by what that characteristic is and how it influences the signal. The former paper uses “energy density” (a scalar) which is proportional to distance (r-4) from bodies. All the characteristics of the former paper were accounted in the original calculation of the Pioneer Anomaly. The latter paper used a vector proportional to r-2, a gravitational force exerted on photons that was not accounted. The different treatment of r by the latter provides a more accurate treatment of the periodicities and all 10 anomalous characteristics of the Pioneer Anomaly. The conclusions of the former that the velocity of light is Galilean additive and the use of the “gravitational density” are not supported.

Numerical modeling of low-frequency distributed acoustic sensing signals for mixed-mode reactivation

In recent years, the development of distributed acoustic sensing (DAS) technology has enabled direct monitoring of subsurface strain during hydraulic fracturing (HF) operations. Most low-frequency (<1 Hz) DAS (LFDAS) signals exhibit strain or strain-rate patterns that are characteristic of propagating tensile hydraulic fractures. However, mixed-mode fault reactivation, consisting of shear slip (mode II) with tensile opening (mode I), can occur in cases where propagating hydraulic fractures intersect preexisting natural fractures or faults. In this study, we show an anomalous LFDAS signal that was observed during an HF operation, with characteristics that differ from typical signals from tensile hydraulic fractures. Anomalous characteristics include the onset of an asymmetric compression-extension doublet after pumping was terminated. The location of the signals, coupled with the image log and seismic data, suggests that mixed-mode reactivation occurred on a preexisting fault. We use a simplified numerical model based on the displacement discontinuity method (DDM) to simulate the anomalous LFDAS signal. Results find that the first-order characteristics of the anomalous signal can be approximated as an initial tensile fault opening (mode I) followed by a shear slip (mode II) on a fault. Therefore, we demostrate the approach of using DDM to investigate mixed-mode fault reactivation during HF operations.

Direct Observation of Contact Reaction Induced Ion Migration and its Effect on Non-Ideal Charge Transport in Lead Triiodide Perovskite Field-Effect Transistors.

The migration of ionic defects and electrochemical reactions with metal electrodes remains one of the most important research challenges for organometal halide perovskite optoelectronic devices. There is still a lack of understanding of how the formation of mobile ionic defects impact charge carrier transport and operational device stability, particularly in perovskite field-effect transistors (FETs), which tend to exhibit anomalous device characteristics. Here, the evolution of the n-type FET characteristics of one of the most widely studied materials, Cs0.05 FA0.17 MA0.78 PbI3, is investigated during repeated measurement cycles as a function of different metal source-drain contacts and precursor stoichiometry. The channel current increases for high work function metals and decreases for low work function metals when multiple cycles of transfer characteristics are measured. The cycling behavior is also sensitive to the precursor stoichiometry. These metal/stoichiometry-dependent device non-idealities are correlated with the quenching of photoluminescence near the positively biased electrode. Based on elemental analysis using electron microscopy the observations can be understood by an n-type doping effect of metallic ions that are created by an electrochemical interaction at the metal-semiconductor interface and migrate into the channel. The findings improve the understanding of ion migration, contact reactions, and the origin of non-idealities in lead triiodide perovskite FETs.

Flight Characteristics of UAP (Unidentified Aerial Phenomena) From The Perspective of Propulsion Principle–Flight Performance Derived from Propulsion Principle

This paper elucidates the entity of UAP (Unidentified Aerial Phenomena) and its unique flight performance from the viewpoint of propulsion theory. Unidentified Aerial Phenomena (UAP) partially identified as being unknown anomalous aircraft, referred to as Unidentified Anomalous Vehicles (UAVs) or Unidentified Flying Objects (UFOs), have been observed globally. These unidentified craft typically exhibit anomalous flight characteristics, such as traveling at extremely high speeds, changing direction or accelerating at extremely high rates, and hovering motionless for long periods of time. UAP is a manned spacecraft capable of interstellar travel, and an aircraft that flies freely within the planet's atmosphere when it reaches the planet. The flight mechanism is the same principle as the gravity generation mechanism, and is derived from the acceleration generated by the curvature of space, that is, the curved space, which comes from the nature of space as a continuum. From the perspective of space propulsion physics, this paper clarifies the substance of the UAP, including its propulsion principle, propulsion mechanism, and the characteristic flight performance of the UAP that is inevitably obtained therefrom.