bluuebunny/crossref_metadata_2025 huggingface dataset:
A thermal load identification method based on physics-guided neural network for honeycomb sandwich structures
Authors: Du Wenqi , Yang Lekai , Lu Lingling , Le Jie , Yu Mingkai , Song Hongwei , Xing Xiaodong , Huang Chenguang
Published: May 2023

The identification of thermal load/thermal shock of aircraft during service is beneficial for collecting information of the service environment and avoiding risks. In the paper, a method based on multivariate information fusion and physics-guided neural network is developed for the inverse problem of thermal load identification of honeycomb sandwich structures. Two thermal feature parameters: temperature gradient and temperature variation rate are used to build the dataset. A 16-layers physics-guided neural network is presented to achieve the predicted results consistent with physical knowledge. In the work, laser irradiation is used as the thermal load, and two laser parameters are to be identified, i.e. spot diameter, power. Simulations and experiments are conducted to verify the effectiveness of the proposed method. The effects of physics-guided loss function and multivariate information fusion are discussed, and it is found that the results based on the proposed method are much better than the results based on the method without physical model. Besides, results based on multivariate information fusion are better than results based on single temperature response. Then, the effects of network models and hyper parameters on the proposed method are also discussed.
Superfluidity from correlations in driven boson systems
Authors: Mateos Jesús , Creffield Charles E , Sols Fernando
Published: May 2023

We investigate theoretically the superfluidity of a one-dimensional boson system whose hopping energy is periodically modulated with a zero time average, which results in the suppression of first-order single-particle hopping processes. The dynamics of this Floquet-engineered flat-band system is entirely driven by correlations and described by exotic Hamiltonian and current operators. We employ exact diagonalization and compare our results with those of the conventional, undriven Bose–Hubbard system. We focus on the two main manifestations of superfluidity, the Hess-Fairbank effect and the metastability of supercurrents, with explicit inclusion of an impurity when relevant. Among the novel superfluid features, we highlight the presence of a cat-like ground state, with branches that have opposite crystal momentum but carry the same flux-dependent current, and the essential role of the interference between the collective components of the ground-state wave function. Calculation of the dynamic form factor reveals the presence of an acoustic mode that guarantees superfluidity in the thermodynamic limit.
Investigation of stability for Cs2TiBr6 perovskite materials exposed to air environment
Authors: Lapa Havva Elif , Çalık Adnan , Kaleli Murat , Aldemir Durmuş Ali
Published: May 2023

Lead-free all-inorganic Cs2TiBr6 perovskite solar cells have attracted attention with their 3.3% efficiency and stability. However, instability in air ambiance has been reported for Cs2TiBr6 synthesized in powder form. In this work, Cs2TiBr6 perovskite is synthesized using a solution-based method. Time-dependent x-ray diffraction patterns are analyzed for air ambience. Cs2TiBr6 perovskite quickly deteriorates and decomposes in the air. Morphology and optical properties are obtained using a scanning electron microscope and the ultraviolet region, respectively. The average particle size is ∼2.4 μm. The forbidden band gap is found to be 1.82 eV from the Tauc plot. The Hall Effect measurement of the perovskite pellet is taken at room temperature and under vacuum. The pellet has high resistivity (1.1 × 104 ohm·cm) and high Hall mobility (502 cm2V−1s−1). Cs2TiBr6 shows p-type conductivity. Low stability to air and high resistivity are handicaps for the Cs2TiBr6 perovskite absorber layer in solar cell applications.
A receipt-free quantum voting protocol based on quantum public key encryption and quantum key agreement
Authors: Ke Weiyang , Shi Run-hua , Yu Hui , Xu Xiaotong
Published: May 2023

To better protect the privacy of voters, a receipt-free quantum voting protocol is first proposed, which adopts quantum key agreement and quantum public key encryption with single photons. We employ Lagrange interpolation polynomials and random numbers to blind the voting information on the bulletin board, so that it can minimize the public information. Furthermore, our receipt-free quantum voting protocol is information-theoretically secure, i.e., the eavesdropper cannot get any voting information by collecting both the quantum ciphertext and the public information. In addition, compared with the existing quantum voting protocols, our protocol can meet more security attributes, such as anonymity, unrepeatability, verifiability legitimacy and especially, receipt-freeness.
Magnetic impurity inducing local defect of polarization and depletion of magnetization in magnetic cluster: blended ferron formation
Authors: Jipdi M N , Dongmo M Z , Fai L C , Tchoffo M
Published: May 2023

This paper presents a blended ferron in a ferromagnetic cluster where the electric polarization and magnetization tailor the quasi-particle characteristics. The resulting quasi-particle has coupled acoustic-polaron and ferron characteristics. The constant competition between electric polarization and magnetization alters the effective mass thereby reducing the global inertia of the quasi-particle. The impurity significantly affects the environment, and the resulting defects in the polarization and magnetization are soliton-like. It was observed that any gain in electric polarization is conveyed by a drop in magnetization, where the hybridization of magnetization and polarization gives rise to a new quasi-particle concept: a blended ferron. The latter is manifested by the local deformation of the electric polarization and depletion of the magnetization in the cluster’s signature of magnetic reordering.
Relativistic effects in ionization of heavy hydrogen-like ions by short x-ray pulses
Authors: Novak O , Diachenko M , Kholodov R
Published: May 2023

The probability of photoionization of a heavy hydrogen like ion is calculated within the relativistic perturbation theory. The Coulomb potential of a heavy nucleus is taken into account accurately by usage of the corresponding solutions of the Dirac equation. The obtained probability is compared with both nonrelativistic limit and with nonperturbative results based on the numerical solution of the time-dependent Dirac equation. Suppression of ionization is observed in the secondary ionization channel at photon frequency of about ℏ
ω ≈ mc
2.
Optimistic multigranulation roughness of fuzzy bipolar soft sets by soft binary relations and its applications
Authors: Mubarak Asad , Mahmood Waqas , Shabir Muhammad
Published: May 2023

Two important mathematical methods for addressing uncertainty in data processing are multigranulation rough set (MGRS) and fuzzy bipolar soft set (FBSS). This paper describes a certain kind of multigranulation rough set in the context of multiple soft binary relations. We first define the multigranulation roughness of fuzzy bipolar soft sets in the two universes. Moreover, a detailed study of structural properties has been conducted in order to explore this concept. The key characteristics of the traditional MGRS model are completely preserved in this new approach. Following that, we suggest two decision-making algorithms with respect to aftersets and foresets of the soft binary relations over dual universes. This approach appears to be better suited and more adaptable than other available methods, making it a favorable option for addressing decision-making problems. Finally, we provide a practical application of the suggested approach to a real-world problem.
Chirp characteristics and the effect of chirp on the beam quality of laser pulses propagating upwards in the atmosphere
Authors: Zhang Gan , Ji Xiaoling
Published: May 2023

The chirp characteristics and the effect of chirp on the beam quality of laser pulses propagating from the ground through the atmosphere to the space orbit are studied. The analytical expressions of the additional chirp caused by group-velocity dispersion (GVD) and self-focusing effects in the atmosphere are derived, respectively. It is shown that the behavior of the additional chirp caused by GVD effect is quite different from that caused by self-focusing effect. On the other hand, it is found that there exists a minimum of pulse width on the target when a certain negative initial chirp arrives. In particular, it is demonstrated that the beam quality on the target can be optimized (i.e., the target intensity can be improved and the temporal pulse splitting on the target can be avoided) by the preliminary chirp method.
Key technologies of dynamic simulation and design for large caliber truck-mounted artillery
Authors: Shan Chunlai , Gu Bin , Liang Hui , Liu Pengke , Ning Bianfang
Published: May 2023

Large caliber truck-mounted artillery is a popular weapon developed and equipped in recent years because of its advantages of low cost, high mobility and strong firepower. However, in the firing process of vehicle mounted artillery, it is bound to face the problems which traditional towed artillery or tracked self-propelled artillery does not have. Taking a large caliber truck-mounted artillery as object, a whole artillery dynamics virtual prototype is established and three key technologies of dynamics simulation are studied, which are the influence of turret race waggling on the force of elevating equilibrator and other mechanisms, the top-down optimization design method of the spade, and the influence of tire support on firing stability. The results show that the turret race shaking will directly affect the force magnitude and even direction of the elevating mechanism, and the influence of the angular acceleration of the rotating part given by the turret race shaking needs to be considered; In order to achieve lightweight design, the design parameter of the mechanism such as the spade should be taken as the optimal value in combination with the firing stability of the gun. The traditional truck-mounted artillery usually does not take the driving system as the bearing structure during firing, but it is found that when the wheels land and provide a certain proportion of support force, it is helpful to maintain the vehicle body position. The research can provide reference to the dynamic simulation and design technology of related vehicle weapons.
Study on Flame Retardancy of Enamelled Wires Using a Cone Calorimeter
Authors: Wang K , Kong GQ , Shao M , Yu QB , Yang RJ
Published: May 2023

The flame-retardancy of enamelled wires was studied by using a cone calorimeter. The characteristic parameters including time to ignition, heat release rate, total smoke release and so on, were obtained. The effect of heat radiation flux on the flame retardancy was analyzed. The results show that the flame retardancy of enamelled wires is related to the content of different components in the composite insulation layer. Polyimide enamelled wires have good flame retardant performance, followed by corona resistant wire with filler, and ordinary polyamide imide composite polyester imide enamelled wire has poor flame retardant performance. In conclusion, the heat release rate measured by cone calorimeter can be used for evaluate the flame retardancy of enamelled wires and provide a reference for the development and application of flame retardant enamelled wires.
Influence of Rupture Size on Dispersion Characteristics of Propellant Particles During Ignition and Flame Spreading Processes for Modular Charges
Authors: Yang Xuguang , Yu Yonggang
Published: May 2023

During ignition and flame spreading processes, the difference in initial rupture size for the end cover of cartridge may affect the final accumulation form of propellant particles. A 3D unsteady state gas -solid two-phase flow model was established based on the gas phase-grain phase coupling method to simulate the final distribution of propellant particles in the chamber under different initial rupture sizes for end cover. The simulation results showed that at the fan-shaped initial perforation area for end cover of modular cartridge, under the 6 simulated working conditions of central angles 0, 30, 60, 90, 120 and 150 degrees, the propellant particles in the chamber presented a combined form of gentle slope accumulation, horizontal accumulation, and steep slope accumulation from the primer side to the pressure control diaphragm side. When the central angle corresponding to the fan-shaped initial perforation area increased from 0 ° to 150 °, the axial length for gentle slope accumulation and horizontal accumulation increased from 269 mm to 331 mm, and for the part of horizontal accumulation, the average thickness of propellant particles increased from 18.1 mm to 23.5 mm, and the proportion of steep slope accumulation of propellant particles decreased from 70.3% to 63.8%. The larger the initial rupture size for the end cover, the longer the axial length of gentle slope and horizontal accumulation, the thicker the average grain thickness for the part of horizontal accumulation, and the lower the proportion of steep slope accumulation of propellant particles.
Key Technology Research of Autonomous Attack Tactical Missile
Authors: Jiao Y J , Zhao J M , Zhou J , Wang S Q , Nie C , Nan X M
Published: May 2023

The autonomous attack tactical missile is not only an important development direction of the army’s precision strike equipment in the future, but also the only way to achieve spanning development of the army’s anti-tank missiles. With the advancement of technological progress, the technical breakthroughs made in the fields of multi-source information fusion, autonomous identification, autonomous guidance and controllable damage will be directly applied to the autonomous attack tactical missile to realize autonomous attack. They will lead the army’s equipment to develop from informatization to autonomy and intelligence. Through the combat capacity design for autonomous attack tactical missiles, we put forward the three-ring design method, constructed the combat capacity support elements, sort out the main technical characteristics of autonomous attack level by level, summarized the key technologies from “reconnaissance-strike-evaluation”, the all-element kill chain of autonomous attack, and proposed solutions that may represent the future development direction based on the current research status at home and abroad.
Numerical study on the propagation characteristics of rotating detonation waves in a ramjet engine
Authors: Feng W K , Zheng Q , Xiao Q , Weng C S
Published: May 2023

The rotating detonation ramjet engine (RDRE) is a new-generation aero-engine with tremendous potential. In order to reveal the characteristics of the wave system in RDRE and study the propagation characteristics of the rotating detonation wave (RDW), a three dimensional numerical simulation on a simplified model of RDRE was performed with premixed ethylene/air mixture. The results show that an upstream oblique shock wave (UOSW) is induced by the RDW. It then weakens gradually as propagating upstream and merges with the circumferential tilted normal shock wave (NSW). The UOSW near the outer wall propagates faster upstream, whereas the position of the NSW on the inner and outer walls is almost coincident during the process of propagating downstream. The periodic fluctuations of the pressure peaks and the propagation speed of the RDW were observed, and the irregular pre-combustion occurs near the contact surface. The results also indicate that a sustainable dynamic balance of the periodic fluctuation in the intensity of RDW is formed in the RDRE. The irregular pre-combustion causes the irregular fluctuation of the pressure peaks near the contact surface. The UOSW propagates upstream much faster than the NSW propagating downstream, and the estimated ratio of the circumferential range effected by UOSW to the circumferential range effected by NSW is about 1: 5.
Technical Research on Testing Content of Welded Column on Projectile
Authors: Li Qian , Wang Zhiping , Yang Qian , Liu Lin , Li Wenhao , Xi Xiaowen , Qi Xiaobin
Published: May 2023

Based on the assembly and inspection process of projectiles and rockets, this paper studies and analyzes the inspection link and content setting of welding and assembly on the projectile. Combined with the characteristics of the components, it proposes three aspects: inspection of the components, inspection before power-on screening, and pre-delivery inspection after final assembly. The research results of this paper can effectively verify the state of the projectiles and rockets after welding and assembly and improve the assembly quality of the productss.
Research on the sealed launching technology of underwater gun
Authors: Gu Yutao , Chen Xuejun , Wang Jiawen
Published: May 2023

With the progress of military technology, the underwater combat capability of the world’s major naval powers has developed rapidly. In order to effectively deal with the underwater threat, the related technology research of underwater gun is carried out based on supercavitation technology. Due to the particularity of underwater launch environment, the research of underwater gun launch technology still faces many problems. In this paper, the sealed launching technology of underwater gun is taken as the research object. By comparing with submerged launching and air curtain launching, the advantages of sealed launching technology of underwater gun are analyzed, and the muzzle sealing technology, sealed launching interior ballistic technology and continuous stable water entry technology of underwater gun are preliminarily studied. Opinions and suggestions are put forward for related technologies, which can provide reference for underwater gun launch technology research and engineering practice in the future.
Research on reverse design method of special shaped composite structure
Authors: Guo Jianfen , Xu Jingli , Luo Changhong , Zhang Haiyun , Zhang Jianqin , Qin Zhenming , Li Shuhu , Wang Danyong
Published: May 2023

It analysis and discuss the main procedures and their relativity of reverse design. Due to loss of original design data of a composite special-shaped structure, we start from the analysis of reverse design. According to the inner surface forming characteristics, we use the three-coordinate contact measurement to take the points and reverse design the shape, analyze and adjust the design surface to meet the requirements. The surface and solid of composite laminate are formed, and the production data is provided meeting the needs of rapid product development. We should reverse design the product from model analysis, and consider the processes of analysis-measurement-forming as a whole.
Numerical Simulation of the Influence of Interfacial Characteristics of Bulletproof Plates on Ballistic Protection Performance
Authors: Gao B , Peng G , Wang XC , Zhao H , Feng JC , Chen CX , Zhang B
Published: May 2023

The influence of three interfacial characteristics on the ballistic protection performance of double-layer steel plates is concluded through a numerical simulation of penetration of armor-piercing projectiles into double-layer steel plates with different interfacial characteristics. The research results show that the gap between double layers of steel plates has an adverse effect on the ballistic protection performance. The larger the gap is, the worse the ballistic protection performance is; appropriate interlaminar stress on double-layer steel plates can improve the ballistic protection of target plates; when the joint or fixed point of double-layer steel plates is too close to the impact point, the ballistic protection performance will demonstrate a downward trend.
Analysis Model for Damage of PBO Composite Laminate Target by High-Velocity Projectile Penetration
Authors: Chen CX , Wang XC , Peng G , Wang W , Gao B , Feng JC , Zhang B
Published: May 2023

Poly-p-phenylene benzobisoxazole (PBO) fiber is a new fiber with high ballistic performance, such as excellent heat and flame resistance and super mechanical properties. Consequently, increasing attention has been paid to its applications in the field of ballistic resistance. To identify the damage mechanism of PBO composite target caused by the high-velocity penetration of cylindrical projectiles and the energy conversion mode involved in the penetration process, this paper constructs a target damage engineering analysis model using the energy method in combination with stress wave propagation and projectile motion analysis. The residual velocity of the steel cylindrical projectile after perforating a PBO composite laminate is measured through ballistic tests, and it is compared with the value predicted by the analysis model. Comparison results show that the predicted value by the model is in good agreement with the measurement, with an error of less than 2.6%, thereby proving the validity of the constructed analysis model.
Research on The Damage Law of Reinforced Concrete Beams Caused by Cuboid Explosives under Contact Explosion
Authors: Yao H W , Jia X , Huang Z X , Yang C Z , Shang W
Published: May 2023

In order to study the damage law of cuboid explosives to reinforced concrete beams under contact explosion, the damage effect of reinforced concrete beams under the action of different length-to-width ratios, explosive heights and explosive equivalents of cuboid explosives is studied by LS-DYNA numerical simulation.The results show that when the amount of explosives and the height of explosives remain unchanged, and the ratio of length to width is 1:1, the volume of concrete damage is the largest. When the amount of explosives and the length-to-width ratio remain unchanged, the volume of concrete damage decreases with the increase in height. When the length-width-height ratio of the explosive is constant, the damage volume increases linearly with the increase of the explosive equivalent. The damage degree of beam is divided into three grades: Reinforced concrete beam is slightly damaged when the damage volume ratio is η <3%. Reinforced concrete beam is moderately damaged when the damage volume ratio is 3%< η <7%. Reinforced concrete beam is serious damaged when the damage volume ratio is η>7%.
Study of the Influence Factors for Ballistic Performance of Glass Fiber Reinforced Composites
Authors: Xu HM , Wang XB , Wang BC , Xue YJ , Qi YN , Kong LM
Published: May 2023

The study prepares glass fiber reinforced composites through Vacuum Assisted Resin Infusion (VARI) process, selects glass fibers of different specifications, and studies the effects of lay-up mode, thickness, simulated normal incident angle, and temperature of fiber composites s on their ballistic performance. Results show that with slimmer fiber monofilament, reinforced materials perform better in ballistics; the lay-up mode has limited influence on ballistic performance; the relationship between thickness and ballistic performance is positively linear; and the relationship between normal incident angle and ballistic performance is parabolic. Compared with room temperature conditions, the ballistic performance of composites does not decrease and even increases slightly under low temperatures. Yet, the performance decreases sharply at high temperatures.
Finite Element Analysis on the Anisotropic Characteristics of 3D Woven Resin Matrix Composites under Lateral Compression
Authors: Feng GY , Qu FZ , Wang XB , Wang BC , Xue YJ , Fu WQ
Published: May 2023

3D meso-structural composites with three layers were constructed using 3D modeling software Pro/E, and the static anisotropic characteristics of the composites under lateral compression in warp and weft directions were simulated by using finite element analysis software ANSYS. The mechanical properties of the composites under lateral compression were predicted by analyzing the stress and strain distribution of fiber and resin in the composites under lateral compression load. The anisotropic characteristics of composites were then analyzed. Results showed that the lateral compression property of the composites was anisotropic, and the lateral compression performance in weft direction was better than that in warp direction. In the composite, fiber bears more load, and the resin undergoes greater deformation. Fibers whose axial direction is parallel to the lateral compression direction bears greater load, while fibers whose axial direction is perpendicular to the lateral compression direction bears less load.
A Detection Method for Defects in Gun Barrel Made of Carbon Fiber/Ti Alloy Composites
Authors: Tang ZH , Sun LW , Jiang ZQ , Dong FX , Fan LM , Duan J , Sun Y , Zhao FB , Wang CK , Zheng SP , Chen Y
Published: May 2023

This study aims to explore the non-destructive detection method for such defects as debonding and delamination in carbon fiber/Ti alloy composite gun barrels during the preparation process. In this paper, the preparation method of composite barrel defective specimens is first introduced. Then water immersion ultrasonic testing and computed tomography (CT) scan are conducted for the specimens prepared. The results show that water immersion ultrasonic testing can identify the defects between the carbon fiber/Ti alloy layers, but CT scan fails to identify them. Therefore, immersion ultrasonic testing can be applied to the detection of defects between the carbon fiber/Ti alloy layers in composite gun barrels.
Properties of Special Polypropylene Fiber Grade Materials/Propylene-ethylene Copolymer Blends
Authors: Guo C , Liu W , Meng XY , Liu ZF , Zhang FB , Dai Y
Published: May 2023

Special propylene-ethylene copolymer (PEC) and polypropylene (PP) fiber grade materials were blended through the melt-compounding method to prepare the PP/PEC blends in varying proportions. Subsequently, further analysis was carried out on the crystallinity, dispersibility, mechanical properties and flexibility of the PP/PEC blends. The results haven shown that PEC is uniformly dispersed in the PP matrix, whereas the size of the PEC particle is relatively smaller. Moreover, as the content of PEC increases, the crystallization temperature of the PP/PEC blends (T
cp) would experience increases accordingly. In addition, the Young’s modulus and the tensile strength of the PP/PEC blends would experience decreases with evident increases in the impact strength. Last but not least, the softness of PP would experience increases to a certain extent with the addition of PEC.
Preparation and Properties of Broadband Terahertz Absorbing Coatings
Authors: Qiu GH , Wang W , Han JL , Zhang RR , Han L , Wang YK , Yu MX
Published: May 2023

This study designs and prepares broadband terahertz absorbing coatings. The electromagnetic simulation software is used to simulate and analyze the influence of permittivity, thickness of the coatings and incident angle of terahertz wave on the reflectivity of the absorption coatings within the range of 0.25 THz ~ 3 THz. Results show that as the real part of the dielectric constant and thickness increase, the low-reflection peak moves to lower frequencies. When the imaginary part of the dielectric constant and incident angle change, the intensity of the reflectivity peak changes relatively vastly. Terahertz absorption coatings with different thicknesses are prepared, and the reflectivity test results are consistent with the simulation results. The coatings have excellent absorption performance within the range of 0.25 THz ~ 3 THz, and the absorption exceeds 2.5 THz when the bandwidth is lower than -10dB.
Effect of Bubble and Void Defects on Properties of Structural Armor Composites
Authors: Wang BC , Wang XB , Xu HM , Fu WQ , Kong LM
Published: May 2023

The effect of bubbles and void defects on the properties of structural armor composite was investigated, and the properties of the composites repaired following the secondary infusion scheme were characterized. The results showed that bubbles could significantly decrease the mechanical properties of composites, the tensile strength and bending strength of the composites with bubbles were decreased by about 11% and 5% respectively, and the bending modulus of elasticity was 9% less. The ballistic performance of the composites with void defects was decreased. For V50, it was decreased by about 6%, and the specific energy absorption was reduced by about 9%. The void defect has little effect on the static mechanical properties of the composites, but will significantly reduce the anti-aging ability of the composites in hygrothermal environment. The mechanical properties and ballistic performance of the composites do not decrease significantly after the secondary infusion in the dry spot area.
Preparation and Performance of Carbon Nanotubes Reinforced Ultra-high Molecular Weight Polyethylene Fibre-based Composites
Authors: Liu FB , Li H , Wang RH , Xu JL , Li SH , Wang DY , Zhang HY , Zhang JQ , Jia HM , Liu Y , Gao YY
Published: May 2023

This study treated the surface of ultra-high molecular weight polyethylene (UHMWPE) fibres with plasma and optimized the parameters of plasma treatment. On this basis, UHMWPE fibre composites reinforced with carbon nanotubes (CNTs) were prepared, and the changes of UHMWPE fibres before and after modification in the chemical composition, surface morphology, and mechanical properties were studied. The results showed that oxygen-containing functional groups and active free radicals on the surface of plasma treated UHMWPE fibres increased. Tensile strength and modulus of UHMWPE fibre composites reinforced with CNTs increased by 16.3% and 21%.
Swarm Operation System and Its Intelligent Development
Authors: Zeyu Xu , Feng Hao , Yongzhou Wang , Yutong Bai
Published: May 2023

As a new operational pattern for the intelligent, unmanned, and networked battlefield in the future, swarm operation has become a research focus of all countries for its unique strengths and has been playing an increasingly important role in warfare. The origin and development trend of swarm operations are reviewed in this paper, to lay a foundation for future studies in this realm. Domestic and foreign development progress are summarized; representative swarm operation projects in the United States are introduced; and key technologies for intelligent swarm operations are analyzed for different operational missions.
Multidisciplinary design optimization for rapid revisit missile early warning constellation system
Authors: Mao Nengfeng , Long Teng , Shi Renhe , Wu Yufei , Ye Nianhui
Published: May 2023

In order to improve the comprehensive design performance of the missile early warning constellation system (MEWCS), the multidisciplinary design optimization (MDO) for rapid revisit MEWCS is studied. The MDO problem consists of orbit, coverage, attitude and orbit control, payload, power, and structure disciplines, which is formulated to minimize the revisit time subject to the constraints such as eclipse time, signal to noise ratio, and entire mass of satellite. To efficiently and effectively solve the studied MDO problem, a filter-based mode pursuing sampling intelligent exploring method using discriminative coordinate perturbation (FMPS-DCP) is used to obtain the optimized configuration of constellation and optimized parameters of satellite system. The engineering example shows that the revisit time of MEWCS for the target area is significantly reduced after optimization, which illustrates the effectiveness and practicality of the work in this paper.
Development and Application of Intelligent Test Data Management Platform of Military Product Model Project
Authors: Yang K , Peng Y L , He Y , Xu Y
Published: May 2023

This paper first introduces the composition of the intelligent test data management platform of military product model project, which has the functions of data file management, acquisition, tagging, pre-processing, archiving, intelligent analysis and judgement, etc. Then the software module design of the platform and the main functions of each module are described. Finally, the advantages of the platform, such as easy operation, practicability, expansibility, easy management, easy maintenance and intelligentization, and the problems that need to be optimized are discussed.
Development and Prospect of Intelligent Air-to-Ground Precision Strike Munition
Authors: Wenyuan Zhang , Sheng Luo , Jun Wang , Jian Zhou , Yanfang Cai
Published: May 2023

Intelligent munition, which integrates networking, big data, deep learning and other artificial intelligence (AI) technologies, is increasingly become the key to military reforms and combats in the future. Therefore, this study defines the connotations and features of intelligent air-to-ground precision strike munition, and provides an analysis on the development status and trend of such munition at home and abroad from the aspects of single intelligence and swarm intelligence. By drawing experience from the development of the U.S. army, this paper elaborates on the ways of establishing the technological system of intelligent air-to-ground precision strike munition from three aspects, namely, single intelligent technology, system integration and operational application. The study is expected to promote the research and development of the next generation of air-to-ground precision strike munition with intelligent features including perception, learning, decision-making and collaboration.
Discussion forum for the learning of Modern Physics in high school Mexico
Authors: Ramírez Díaz M. , Ávila García G. , Escobar Moreno F.
Published: May 2023

This research refers to the B-Learning educational model using the Moodle platform in the learning of Relativistic Physics as a complement to face-to-face classes in the high school modality, seeking mainly to stimulate the construction of the student’s own knowledge, oriented towards the autonomy of the student The activity was carried out through the implementation of a discussion forum with a sample of 20 high school students. The methodology is of a qualitative nature, which refers to the analysis of the data with the Atlas.ti platform, considering the nuclear variable of communication and the associated codes of significant interaction namely, guided didactic conversation, social interaction, open communication, simulated communication and discussion. The platform allows us to recognize the relevance of communication towards student learning through a discussion forum, that is confirmed through the correlations found between the codes. The results obtained through this analysis indicate the type of communication that students have when they participate in a forum for understanding the topic of Relativity, categorized with the codes, and that reveals the exchange that may or may not be significant about the content that is proposed in the discussion. Although more solid arguments are lacking among the students, the importance of communication as one of the competences of the 21st century is developed, and, above all, the close accompaniment of the teacher with recommendations and proposals for searching for information. In addition, the proposed evaluation allows the teacher to recognize the points where his contribution should be reinforced and, above all, lead to a self-assessment of the students.
Enhanced beam shifts mediated by bound states in continuum
Authors: Sinha Biswas Sounak , Remesh Ghanasyam , Achanta Venu Gopal , Banerjee Ayan , Ghosh Nirmalya , Dutta Gupta Subhasish
Published: May 2023

The interaction of light beams with resonant structures has led to the development of various optical platforms for sensing, particle manipulation, and strong light–matter interaction. In the current study, we investigate the manifestations of the bound states in continuum (BIC) on the in plane and out of plane shifts (referred to as Goos–Hänchen (GH) and Imbert–Fedorov (IF) shifts, respectively) of a finite beam with specific polarization incident at an arbitrary angle. Based on the angular spectrum decomposition, we develop a generic formalism for understanding the interaction of the finite beam with an arbitrary stratified medium with isotropic and homogeneous components. It is applied to the case of a Gaussian beam with p and circularly polarized light incident on a symmetric structure containing two polar dielectric layers separated by a spacer layer. For p-polarized plane wave incidence one of the coupled Berreman modes of the structure was recently shown to evolve to the bound state with infinite localization and diverging quality factor coexisting with the other mode with large radiation leakage (Remesh et al 2021 Opt. Commun.
498 127223). A small deviation from the ideal BIC resonance still offers resonances with very high quality factors and these are exploited in this study to report giant GH shifts. A notable enhancement in the IF shift for circularly polarized light is also shown. Moreover, the reflected beam is shown to undergo distortion leading to a satellite spot. The origin of such a splitting of the reflected beam is traced to a destructive interference due to the left and right halves of the corresponding spectra.
Fluid flow analysis of the lattice-based ceramic filters in molten metal filter application
Authors: Chouhan Ganesh , Bidare Prveen , Murali Gunji Bala , Pradhan Jitenjaya
Published: May 2023

The ceramic lattice filters are ideal for various technical applications, including filtration, flow stability, and heat transfer, that could alter the transport characteristics like pressure, permeability, and velocity. The authors presented a computational study based on the fluid flow parameters for four struts-based lattice structures in this work. This study includes seven designs of four struts-based lattice structures systematically created with 30 pores per inch (PPI) and 80% porosity while varying the unit cell sizes and strut diameter. The present computational study has been carried out using the turbulent k-epsilon (k-ε) model with the chosen metal alloy, IN718. The efficacy of the lattice filters has been determined by visualizing the physical parameters like pressure drop and velocity distribution patterns inside the filters. This study concludes that the BCC and the Diamond lattice structures have outperformed the other designs. Moreover, the effects of the variation in the unit cell and strut size have been evaluated for different structures and discussed.
Public and private transportation in Chinese cities: impacts of population size, city wealth, urban typology, the built environment, and fuel price
Authors: Fu Xiangwen , Mauzerall Denise L , Ramaswami Anu
Published: May 2023

The development of urban transportation is affected by city population size, wealth, urban typology, the built environment, and fuel price, and has significant implications for urban sustainability. We analyze data of 297 Chinese cities between 2017 and 2019 using both simple regressions to examine the relationships between metrics of public and private transportation and city size, and multiple regressions to examine the impacts of the above urban factors on public transit use and private vehicle number. Both public transit use and private vehicle number scale super-linearly with population and sub-linearly with gross regional product. We find that the impacts of population size, city wealth, the built environment, and fuel price on transportation vary across city groups (industrial, mixed-economy, and commercial cities). We find that the relationships between urban transportation metrics and their factors extracted from intra-city variations over time are different from those derived from pooling data of multiple cities over time, indicating the importance of choosing appropriate analyses to inform local policymaking. A key finding is that to reduce private vehicle ownership, enhancing land use diversity, increasing rail transit, and expanding taxi fleets are more effective than increasing density in already dense Chinese cities. Our findings improve understanding of the drivers of public and private transportation in urban China which are needed to promote sustainable growth of Chinese cities.
Corrigendum to “On Lau’s conjecture”
Authors: Salame Khadime
Published: May 2023

This corrigendum makes a correction to K. Salame, “On Lau’s conjecture”, Proc. Amer. Math. Soc. 148 (2020), no. 1, pp. 343–350.
Boundaries of dense subgroups of totally disconnected groups
Authors: Björklund Michael , Hartman Yair , Oppelmayer Hanna
Published: May 2023

Let

Γ
\Gamma

be a countable discrete group and let

H
H

be a lcsc totally disconnected group,

L
L

a compact open subgroup of

H
H

, and

ρ
:
Γ
→
H

\rho : \Gamma \rightarrow H

a homomorphism with dense image. In this paper we construct, for every bi-

L
L

-invariant probability measure

θ
\theta

on

H
H

, an explicit Furstenberg discretization

τ
\tau

of

θ
\theta

such that the Poisson boundary

(

B
θ

,

ν
θ

)

(B_\theta ,\nu _\theta )

of

(
H
,
θ
)

(H,\theta )

is a

τ
\tau

-boundary, where

Γ
\Gamma

acts on

B
θ

B_\theta

via the homomorphism

ρ
\rho

. We also provide several criteria for when this

τ
\tau

-boundary is maximal.

Our technique can for instance be used to construct examples of finitely supported random walks on certain lamplighter groups and solvable Baumslag-Solitar groups, whose Poisson boundaries are prime, but not

L
p

L^p

-irreducible for any

p
≥
1

p \geq 1

, answering a conjecture of Bader-Muchnik in the negative.

Furthermore, we provide the first example of a countable discrete group

Γ
\Gamma

and two spread-out probability measures

τ
1

\tau _1

and

τ
2

\tau _2

on

Γ
\Gamma

such that the boundary entropy spectrum of

(
Γ
,

τ
1

)

(\Gamma ,\tau _1)

is an interval, while the boundary entropy spectrum of

(
Γ
,

τ
2

)

(\Gamma ,\tau _2)

is a Cantor set.
Static Injection, Migration, and Equalization (SIME): A New Paradigm for Safe Ultrasound-Guided Brazilian Butt Lift: Safer, Faster, Better
Authors: Pazmiño Pat , Del Vecchio Daniel
Published: May 2023

Background

Although the Brazilian butt lift (BBL) is one of the most popular procedures in body contouring, it has been associated with the risk of pulmonary fat embolism when fat graft is injected into the gluteal muscles. The subcutaneous plane has been identified as a safe site for fat graft injection, but deaths from fat embolism continue to occur because there is no mechanism to confirm consistent subcutaneous placement.

Objectives

The aim of this paper was to determine if real-time intraoperative ultrasound could accurately identify the subcutaneous gluteal anatomic landmarks and permit a single surgeon to consistently target fat graft placement in the subcutaneous space.

Methods

In total, 4150 BBLs were performed with real-time intraoperative ultrasound being used to confirm the subcutaneous position of a static cannula during fat graft injection. Serial deposits of fat graft were performed in each buttock. Ultrasound confirmed that fat graft consistently remained above the deep gluteal fascia and migrated through the deep subcutaneous space. These fat graft deposits were then equalized with a moving cannula to correct any contour deformities. Operative times were recorded and compared with BBL performed by expansion vibration lipofilling without ultrasound.

Results

Real-time intraoperative ultrasound allowed for the visual confirmation of consistent subcutaneous fat graft deposition and the targeting of fat graft into specific gluteal subcutaneous compartments.

Conclusions

Real-time intraoperative ultrasound allows the surgeon to confirm a subcutaneous-only fat graft injection, target specific gluteal subcutaneous compartments, and take advantage of the unique architecture of the deep subcutaneous space to create gluteal projection and correct contour deformities.
Prognostic value of right ventricular global longitudinal strain in patients with immunoglobulin light-chain cardiac amyloidosis
Authors: Usuku Hiroki , Yamamoto Eiichiro , Sueta Daisuke , Noguchi Momoko , Fujisaki Tomohiro , Egashira Koichi , Oike Fumi , Fujisue Koichiro , Hanatani Shinsuke , Arima Yuichiro , Takashio Seiji , Kawano Yawara , Oda Seitaro , Kawano Hiroaki , Matsushita Kenichi , Ueda Mitsuharu , Matsui Hirotaka , Matsuoka Masao , Tsujita Kenichi
Published: May 2023

Aims

Left ventricular (LV) global longitudinal strain (GLS) (LV-GLS) is a strong and independent predictor of outcomes in patients with immunoglobulin light-chain (AL) cardiac amyloidosis. This study was performed to investigate whether right ventricular (RV) GLS (RV-GLS) provides prognostic information in patients with AL amyloidosis.

Methods and results

Among 74 patients who were diagnosed with AL cardiac amyloidosis at Kumamoto University Hospital from December 2005 to December 2022, 65 patients who had enough information for two-dimensional speckle tracking imaging and did not receive chemotherapy before the diagnosis of cardiac amyloidosis were retrospectively analysed. During a median follow-up of 359 days, 29 deaths occurred. In two-dimensional echocardiographic findings, LV-GLS, left atrium reservoir strain (LASr), and RV-GLS were significantly lower in the all-cause death group than in the survival group (LV-GLS: 8.9 ± 4.2 vs. 11.7 ± 3.9, P < 0.01; LASr: 9.06 ± 7.28 vs. 14.09 ± 8.32, P < 0.05; RV-GLS: 12.0 ± 5.1 vs. 16.8 ± 4.0, P < 0.01). Multivariable Cox proportional hazard analysis showed RV-GLS was significantly and independently associated with all-cause death in patients with AL cardiac amyloidosis (hazard ratio 0.85; 95% confidence interval, 0.77–0.94; P < 0.01). Receiver operating characteristic analysis showed that the area under the curve of RV-GLS for all-cause death was 0.774 and that the best cut-off value of RV-GLS was 14.5% (sensitivity, 75%; specificity, 72%). In the Kaplan–Meier analysis, patients with AL cardiac amyloidosis who had low RV-GLS (<14.5%) had a significantly higher probability of all-cause death (P < 0.01).

Conclusion

RV-GLS has prognostic value in patients with AL cardiac amyloidosis and provides greater prognostic power than LV-GLS and LASr.
Congenital heart defects caused by FOXJ1
Authors: Padua Maria B , Helm Benjamin M , Wells John R , Smith Amanda M , Bellchambers Helen M , Sridhar Arthi , Ware Stephanie M
Published: May 2023

FOXJ1 is expressed in ciliated cells of the airways, testis, oviduct, central nervous system and the embryonic left–right organizer. Ablation or targeted mutation of Foxj1 in mice, zebrafish and frogs results in loss of ciliary motility and/or reduced length and number of motile cilia, affecting the establishment of the left–right axis. In humans, heterozygous pathogenic variants in FOXJ1 cause ciliopathy leading to situs inversus, obstructive hydrocephalus and chronic airway disease. Here, we report a novel truncating FOXJ1 variant (c.784_799dup; p.Glu267Glyfs*12) identified by clinical exome sequencing from a patient with isolated congenital heart defects (CHD) which included atrial and ventricular septal defects, double outlet right ventricle (DORV) and transposition of the great arteries. Functional experiments show that FOXJ1 c.784_799dup; p.Glu267Glyfs*12, unlike FOXJ1, fails to induce ectopic cilia in frog epidermis in vivo or to activate the ADGB promoter, a downstream target of FOXJ1 in cilia, in transactivation assays in vitro. Variant analysis of patients with heterotaxy or heterotaxy-related CHD indicates that pathogenic variants in FOXJ1 are an infrequent cause of heterotaxy. Finally, we characterize embryonic-stage CHD in Foxj1 loss-of-function mice, demonstrating randomized heart looping. Abnormal heart looping includes reversed looping (dextrocardia), ventral looping and no looping/single ventricle hearts. Complex CHDs revealed by histological analysis include atrioventricular septal defects, DORV, single ventricle defects as well as abnormal position of the great arteries. These results indicate that pathogenic variants in FOXJ1 can cause isolated CHD.