Hole Type Research Articles

Aza-anthradithiophene-based conjugated polymers: Synthesis and field-effect transistor application

Acenedithiophenes are classical fused-ring units for constructing conjugated polymers. In this work, a new aza-anthradithiophene unit has been designed and was for the first time employed as building unit to constructing conjugated polymers for organic field-effect transistors. Two conjugated polymers based on thiophthene (P1) and benzothiadiazole (P2) as co-units were synthesized by Stille and Suzuki coupling reactions, respectively. The thermal stability, optical and electrochemical properties, and microstructure were investigated. Organic field-effect transistor devices based on conjugated polymers as semiconductor layer were also fabricated and two polymers exhibited typical hole transport characteristics with the average field-effect mobility up to 7.9 × 10−4 cm2V−1s−1 and Ion/Ioff ratios over 104.

Entropy of black holes coupled to a scalar field

The Hamiltonian approach to black hole entropy, recently proposed in the framework of Poincar\'e gauge theory, is extended by including the scalar matter. The improved approach is used to analyse asymptotic charges and entropy of a typical black hole with scalar hair in two complementary dynamical settings, in GR and in the teleparallel gravity. In both cases, the results confirm the validity of the first law.

Leakage, diffusion and distribution characteristics of refrigerant in a limited space:A comprehensive review

The leakage and direct emission of high GWP HFC refrigerants in refrigeration, air-conditioning and heat pump systems increase the greenhouse effect, which pose huge threats to the ecological environment and the human health. Meanwhile, some alternative refrigerants with excellent environmental performance have different degrees of flammability. When the flammable refrigerants catastrophically leak from the refrigeration system into a limited space, it is easy to cause an explosion accident, the safety of people and property in the space is greatly threatened. In addition, the operating conditions of refrigeration systems, thermophysical properties of the refrigerants, obstacles and ventilation conditions of the space have a great impact on the process of refrigerant leakage and diffusion, the explosion risks formed in the external space have certain differences. To promote the security application of the alternative refrigerants, the leakage, diffusion, and distribution characteristics of the refrigerants from both theoretical and experimental aspects were reviewed in this work. The potential causes of leakages and common types of leakage holes in refrigeration systems were summarized, and the advantages and disadvantages of the existing leakage and diffusion theoretical models were concluded. The impact of the micro-sized leakage of the refrigerant on the internal of the system was discussed. The diffusion and distribution of the refrigerants in the external space after they catastrophically leaked from different types of systems were analyzed, and the influence of different parameters on the refrigerant distribution and the explosion risk based on the catastrophic leakage was also presented. The future work was prospected. The review is expected to provide a valuable reference for the safety risk assessment of the flammable refrigerants.

Hydrodynamics of the projectile entering the water under the ice hole constraint environment

The study of the water entry of the projectile passing through the ice hole can solve the special issue of water entry under marine environmental constraints. We conducted experiments to validate the effect of the ice hole constraint on the dynamics of the water entry cavity and then used the numerical simulations to investigate the cavity dynamics of the projectile passing through ice holes with different sizes and rotation degrees. The results show that the ice hole affects the evolution of the water entry cavity and the motion state of the projectile. The splash crown flows back and then contacts the projectile surface when passing through the small-sized ice hole. Cavity collapses before the pinch-off. The splash crown flows back at the hole as the hole size increases, the cavity morphology is complete, and the projectile's movement is more stable at the initial stage of water entry and after deep cavity pinch-off. Special oblique jets form when passing through irregular holes. The impact of the oblique jet on the cavity increases as the rotation degree increases. The type of hole has little effect on the water entry dynamics of the projectile, but has a significant effect on the cavity morphology and the jet motion near the hole. The size of the hole has a great effect on the motion stability of the projectile.

Numerical stochastic inflation constrained by frozen noise

Stochastic inflation can resolve strong inflationary perturbations, which seed primordial black holes. I present a fast and accurate way to compute these perturbations in typical black hole producing single-field models, treating the short-wavelength Fourier modes beyond the de Sitter approximation. The squeezing and freezing of the modes reduces the problem to one dimension, and the resulting new form of the stochastic equations, dubbed `constrained stochastic inflation,' can be solved efficiently with semi-analytical techniques and numerical importance sampling. In an example case, the perturbation distribution is resolved in seconds deep into its non-Gaussian tail, a speed-up of factor 109 compared to a previous study. Along the way, I comment on the role of the momentum constraint in stochastic inflation.

Structural Performance of Ferrocement Beams Incorporating Longitudinal Hole Filled with Lightweight Concrete

In this study, 10 ferroconcrete concrete (FC) beams with lightweight cores reinforced with welded steel mesh as a shear reinforcement were evaluated under three-point bending tests along with two conventionally normal-weight concrete (NWC) beams. Expanded polystyrene and lightweight aerated autoclaved brick wastes were used to create lightweight core concrete. The main factors include the type of lightweight concrete used for the core, beam concrete type, the form and number of holes, the existing steel mesh fabric, the hollow, and the hole placement. This study was done on the tested beams' ductility index, failure modes, first cracking loads and associated deflections, and ultimate loads besides corresponding deflections. Experimental results showed that the use of FC, various filling materials, and welded steel meshes in place of traditional stirrups enhanced the ultimate load by 36.6–107.3%, the ultimate deflection by 6–272%, and the ductility by 89–1155% when referenced to a control NWC beam. When the holing ratio increased from 10 to 20%, the ductility of FC beams was enhanced by 307.7%. Proposed equations were developed to predict the ultimate load and bending moment capacity of FC beams while taking into account the compressive strength of the beam body and filling material, the holing ratio, the tensile reinforcement ratio, and the volume fraction of the steel mesh.

Comparison of Different Types of Black Holes

With the deeper exploration on black hole, more and more categories of black holes are defined by astronomers and physicists. The article will discuss the differences in detection and process of accretion between the binary black holes and isolated black holes through analysing previous researches on black holes. To search for binary black holes, whose companion may be luminous, classical methods include spectrum test and calculation of the operation of binary star system are applied. On the other hand, the state-or-art facilities HST are used to detect them based on gravitational lens effect. These two different sorts of black holes also have their unique process of accretion. The binary black holes absorb particles from the stellar wind which is given out by their companion, forming two “minidisk”. The process is accompanied with strong emission of X-ray. Meanwhile, the accretion of isolated black hole forms only one ring of gas. The accretion flow is mostly weak and radioactively inefficient. The reason for these differences can be their separate optical features and relationships with environment. It is aimed at distinguishing the two kinds of black holes with different framework, making them easier to identify only with optical evidence or data on radioactive emission. Therefore, it’s easy to tell the infer structure from evidence that astronomers can comparatively easier obtain about black holes, which is beneficial for further studies about black holes internal structure details. These results shed light on guiding further exploration of black holes.

Equations-of-state deduced form different types of black holes

Black holes are seen as thermodynamical systems. They can be characterized by thermodynamic intensive quantities such as temperature, pressure, and extensive quantities such as entropy and energy density. In this paper, we focus on the thermodynamical properties of (a) Schwarzschild, (b) Reissner–Nordström, (c) Kerr, and (d) Kerr–Newman black holes. These allow to estimate the corresponding equations-of-state (EoS) and the squared speed of sound for each of them. The latter helps to calculate the ratio of the bulk viscosity to the shear viscosity for each of the black holes. We conclude that the resulting EoS enhances when moving from Schwarzschild to Reissner–Nordström to Kerr, and to Kerr–Newman black holes.

Numerical study on film cooling effectiveness from spiral-channel hole

Due to producing better film cooling performance, shaped film holes have attracted a lot of attentions and have been extensively studied. A spiral-channel hole, a new shaped film hole, is proposed to improve the film cooling effectiveness. The flow field, including flow structure inside film hole, velocity distribution and development of vortex pairs, of the spiral-channel hole and cylindrical hole are analyzed based on numerical simulation. And film cooling effectiveness of two types of holes is compared. Compared with the cylindrical hole, the averaged film cooling effectiveness of the spiral-channel hole improves by 97% and 667% in the case of M = 0.5 and M = 1.0, respectively. Inside the spiral-channel hole, the flow field appears a smaller separation zone and the streamline swirls and deviates significantly. The momentum of coolant at outlet of the spiral-channel hole is lower and more uniform in vertical direction and the lateral-velocity at outlet of the spiral-channel hole is larger. As a result, the coolant covers larger area in the spanwise distribution and its coverage area is three times larger than that of the cylindrical hole. The distribution and scale of the vortex, which is composed of large-scale vortex and small-scale vortex and distributes in the vertical direction, is completely different from the kidney vortex pair (cylindrical hole). Eventually, the vortex pairs in the vertical direction merge into a large-scale vortex. Since the destruction of the kidney vortex, this swirling structure is of great significance for improving the film cooling effectiveness.

Renormalization group flow to effective quantum mechanics in the IR in an emergent dual holographic description for spontaneous chiral symmetry breaking

Implementing the Wilsonian renormalization group (RG) transformation in a nonperturbative way, we construct an effective holographic dual description with an emergent extradimension identified with an RG scale. Taking the large$-N$ limit, we obtain an equation of motion of an order-parameter field, here the chiral condensate for our explicit demonstration. In particular, an intertwined structure manifests between the first-order RG flow equations of renormalized coupling functions and the second-order differential equation of the order-parameter field, thus referred to as a nonperturbative RG-improved mean-field theory. Assuming translational symmetry as a vacuum state, we solve these nonlinear coupled mean-field equations based on a matching method between UV- and IR-regional solutions. As a result, we find an RG flow from a weakly-coupled chiral-symmetric UV fixed point to a strongly-correlated chiral-symmetry broken IR fixed point, where the renormalized velocity of Dirac fermions vanishes most rapidly and effective quantum mechanics appears at IR. Furthermore, we translate these RG flows of coupling functions into those of emergent metric tensors and extract out geometrical properties of the emergent holographic spacetime constructed from the UV- and IR-regional solutions. Surprisingly, we obtain the volume law of entanglement entropy in the Ryu-Takayanagi formula, which implies appearance of a black hole type solution in the limit of infinite cutoff even at zero temperature. We critically discuss our field theoretic interpretation for this solution in terms of potentially gapless multi-particle excitation spectra.

Salinity-dependent changes in branchial morphometry and Na+ , K+ -ATPase responses of euryhaline Asian sea bass, Lates calcarifer.

Asian sea bass (Lates calcarifer Bloch, 1790) is a euryhaline fish widely cultured in Asia and Australia. Although it is common to culture Asian sea bass at different salinities, osmoregulatory responses of Asian sea bass during acclimation to various salinities have not been fully observed. In this study, we used scanning electron microscopyto observe the morphology of the ionocyte apical membrane of Asian sea bass acclimated to fresh water (FW), 10‰ brackish water (BW10), 20‰ brackish water (BW20), and seawater (SW; 35‰). Three types of ionocytes were identified in FW and BW fish: (I) flat type with microvilli, (II) basin type with microvilli, and (III) small- hole type. Flat type I ionocytes were also observed in the lamellae of the FW fish. In contrast, two types of ionocytes were identified in SW fish: (III) small-hole type and (IV) big-hole type. Furthermore, we observed Na+ , K+ -ATPase (NKA) immunoreactive cells in the gills, which represent the localization of ionocytes. The highest protein abundance was observed in the SW and FW groups, whereas the highest activity was observed in the SW group. In contrast, the BW10 group had the lowest protein abundance and activity. This study demonstrates the effects of osmoregulatory responses on the morphology and density of ionocytes, as well as protein abundance and activity of NKA. In this study, we found that Asian sea bass had the lowest osmoregulatory response in BW10, because the lowest amounts of ionocytes and NKA were required to maintain osmolality at this salinity.

Numerical investigations of the nozzle performance for a rocket-based rotating detonation engine with film cooling

This study numerically investigates the nozzle performance of a rotating detonation engine with film cooling. The premixed stoichiometric hydrogen/air mixture serves as the reactant, and the pure air is pumped into the film cooling holes. The diverging section of the nozzle is designed based on the characteristic method and the maximum thrust theory. The spike truncation ratio is optimized to ΔLspike = 40% Lcowl, reducing the weight and maintaining a high axial thrust coefficient of 0.9456. In contrast with the steady condition, the flow loss of the practically transient condition mainly comes from three parts. The first is the pressure loss of the continuously sweeping shock waves, the second is the viscous effect of the flow passage, and the third is the energy dissipation of the recirculation zone in the base region. When the film cooling strategies are introduced on the inner and outer walls, the hole type a/b < 1.0/1.0 is preferred thanks to a more considerable coolant coverage induced by more violent interactions between the radial jet and the mainstream. The cooling effects and the aerodynamic performance can be further balanced within a moderate injection velocity. The final optimized nozzle configuration with ΔLspike = 40% Lcowl, a/b = 1.0/2.0, and Vsec = 100 m/s corresponds to an axial thrust coefficient of 0.9552, a discharge coefficient of 0.9344, a pressure gain of -16.48%, and a root mean square deviation of the flow deflection angle of 14.42°.

Sonic black hole duct

The sonic black hole is a type of acoustic black hole that attenuates sound propagation via the acoustic black hole effect. This phenomenon is when an incident acoustic wave propagates through a power-law tapering geometry causing the wavelength to compress, the wave speed to decrease, and the time for the wave packet to reach the exit to extend infinitely. As a result, the wave never reaches the exit, so it cannot be reflected or transmitted. However, this outcome relies on the taper approaching exactly zero, which is impossible to manufacture. Therefore, the taper must be truncated leading to imperfect sound absorption. One method to increase the sound absorption is by applying perforations to the rings. This study explores the effect that varying the perforations on the sonic black hole’s rings has on the absorption coefficient from 1 to 5 kHz.

Algorithms and radiation dynamics for the vicinity of black holes

We present the results of our studies on accretion disks in the proximity of astrophysical black holes. These disks can be of varying degrees of opacity, geometrical shapes, sizes, and volumes. The central compact object is a Schwarzschild or a Kerr black hole of various spin parameters. We describe the environment and the physics of the systems under examination and the disk models considered. We first investigate the effects of the spacetime rotation on photon trajectories. We then examine the radiation forces recorded at various points of the arrangement inside and outside the disk material, and in the inner, outer, and off-equatorial material orbits. We document and explore the radiation effects, which are revealed to be significant and positively consequential. Afterward, we inspect the possible imaging outcome of various types of black hole and accretion disk configurations, and we show our results for plots that could be used to estimate the central black hole spin in a system. Finally, we show results regarding the disk material orbit degradation due to its thermal radiation.

Nest entry shape change may cause nest abandonment in urban cavity-nesting species: a case study of the Tree Sparrow Passer montanus

The threat of predation is the main cause of bird nest abandonment, with such behaviour imposing considerable energetic costs on breeding birds. However, for several species, nest abandonment can be a less costly alternative to complete brood failure. In this study, we examined nest abandonment among Eurasian Tree Sparrows (Passer montanus) by surveying 71 Tree Sparrow nests with various types of entry holes and conducted artificially manipulating some of the entrance shapes. We found that nest abandonment was caused by changes to the nest entry shape in seven cases and by human interference in two cases. Nest abandonments occurred throughout the breeding season, and breeding pairs attempted to breed again immediately after nest abandonment. The results of the artificial nest entry shape manipulation experiment showed that nine of twelve nests (75.0%) were abandoned where the nest entrance holes were widened, and six of eleven nests (54.5%) were abandoned where the nest entrance holes were narrowed. However, none of the nests were abandoned where the entry shape was unchanged. Thus, nest abandonment by Tree Sparrows is correlated with nest entry shape manipulation and is more likely to occur when the energy cost of breeding again is less than that of abandoning the nest.

The State-of-art Theorem and Detection Paradigms of Black Holes

The black hole has been a mystery and a source of detection motivation for the human race ever since our quest of the discovery and research of other space. In general, the black hole can be defined as a special time-space structure where the gravity is strong enough to trap the photons, i.e., the light will be unable to penetrate or escape from it. In this paper, the current theorem and state-of-art detection paradigms are discussed in detail. Primarily, the categories of the black holes are demonstrated. The four different types of black holes all present their unique features. the quest for black hole exploration has never ceased. It has achieved stunning breakthrough with the first ever photo taken of the black hole by NASA in 2019. The future analysis of black hole excavation and research has been brought a bright future, as technology and outer space exploration plans continue to evolve. These results shed light on guiding further exploration of cosmology as well as the astrophysics.

Long term results of central hole type posterior chamber intraocular lens in the correction of moderate to high myopia

Objective: To evaluate the long-term safety,effectiveness,predictability and stability of ICL V4c implantation for moderate to high myopia. Methods: In this retrospective case series study, 95 eyes from 50 patients with moderate to severe myopia who were treated in 2015 underwent central hole type posterior chamber intraocular lens (ICL V4c) implantation at Eye & ENT Hospital of Fudan University. The patients were followed up for a period of five years, during which we assessed various parameters including uncorrected visual acuity (UDVA), corrected visual acuity (CDVA), refractive error, axial length, intraocular pressure, endothelial cell density (ECD), vault, and complications. We used the paired t-test and repeated measures one-way ANOVA in SPSS statistical software to analyze the data. Results: The mean spherical equivalent refraction (SE) decreased significantly from (-12.16±3.04) D preoperatively to (-0.19±0.55) D at one month and (-1.14±0.84) D at five years postoperatively. The safety indices (postoperative CDVA/preoperative CDVA) were 1.24±0.27 and 1.13±0.27, respectively, and the efficacy indices (postoperative UDVA/preoperative CDVA) were 1.14±0.25 and 0.87±0.26 at one month and five years postoperatively. At one month after surgery, 80.00% of the eyes were within ±0.50 D of the expected correction, and 96.84% were within ±1.00 D. There was no significant difference in IOP between preoperative and postoperative measurements. The rate of ECD was 3.87%, and the vault decreased by 106.32 μm at five years postoperatively. Conclusion: ICL V4c implantation is safe and effective with good predictability and stability for long term.

Effects on the glassy phase and electronic structure of [formula omitted] through Mg and Bi substitution

We did a comparative study of non-magnetic ions (N = Mg2+ and Bi3+) substitution effects in the net magnetism of 1D Ca3Co1.85N0.15O6, focusing on the two aspects: hole-type doping and chemical disorder effects. We have also provided a theoretical framework using first-principles-based density functional theory calculations to describe the magnetic structure and electronic properties. The Mg substitution does not influence the overall magnetic scenario of the system but directly strikes the electronic properties, while the Bi substitution brings bond randomness induced enhancement of glassy feature. These effects are distinctly apparent from the Curie–Weiss fit, magnetic relaxation measurements, and density functional theory calculations. Out of the experimentally proposed magnetic structure, the density functional theory calculations suggested that the ferromagnetic state to be the ground state in which the system shows insulator/semiconductor behavior for Bi substitution while shifting of Fermi level towards valence band and band crossing at Fermi level confirms hole type substitution of Mg.

Experimental evaluation of Luneburg lens using radial holes for relative permittivity distribution

In this paper, we describe a novel 3-D Luneburg lens using radial holes. A Luneburg lens can suppress the side lobe of the antenna and increase the gain. The prototype Luneburg lens was fabricated using a 30mm radius dielectric sphere with uniform permittivity by 2.1 and many holes by 1mm radius, called radial holes drilled vertically on the sphere surface. The relative permittivity distribution of the Luneburg lens is realized by changing the number and depth of five types of holes. To confirm the effectiveness of the fabricated Luneburg lens, the far-field radiation pattern at 25GHz was measured using a flanged rectangular waveguide as a wave source. It achieved a high gain of 22.4dBi. The measured radiation pattern generally agreed well with the theoretical radiation pattern of the Luneburg lens, and the validity of the Luneburg lens with radial holes at the quasi-millimeter wave was confirmed. It can be used for beam steering in 5G/6G base stations.

Hole Inpainting Algorithm for Half-Organized Point Cloud Obtained by Structured-Light Section System

The advances in sensors and data processing technologies enrich the types of 3D point clouds acquirement, empowering numerous extensive and novel applications such as 3D reconstruction in various scenarios. However, the hole defects affect the accuracy and fidelity of the acquired point clouds, hindering further development and application of 3D point clouds. Aiming at the hole defects in point clouds, a Bayesian hole inpainting algorithm for the half-organized point cloud is proposed, where the point cloud is obtained by a structured-light section system. The algorithm establishes a Bayesian probability model in the hole region, which adopts specific distributions of the point cloud to estimate the maximum likelihood parameter. Simulation and experimental results show that the proposed approach outperforms other competing algorithms significantly in repairing various types of holes, both in objective and subjective qualities. In addition, the proposed algorithm has better scalabilities in the cases of wrong topology definition and self-intersection confusion. This is the first algorithm specially designed for hole inpainting in half-organized point clouds, which maximizes the comprehensive consideration of local features and global optimization, supplemented by targeted prior knowledge of density, Riemannian manifold, and discrete attributes.