bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the dynamic growth of sugar crystals: A volume diffusion non-steady state model under variable conditions
Authors: Osman Abdelbagi , Rajab Fahd
Published: June 2023

Observing the effect of temperature, concentration, and impurity on the crystal growth rate is accomplished by simulating the growth of sugar crystals. The volume diffusion growth model was used to examine the crystallization process and compare the effect of the three parameters on the growth of sugar crystals. The non-steady-state behavior of the process is examined using MATLAB simulation. A disturbance analysis of temperature, concentration, and impurity has been conducted to demonstrate their impact on the final crystal size of sugar. The findings show that temperature and impurities affect the final sugar crystal size. In addition, the size of crystals can be enhanced by increasing the concentration of sugar solution.
The dynamics of the resonance in a 3:5 external resonant model
Authors: Zhu Di , Zhang Wei , Zuo Hongkun , Zhou Yi
Published: June 2023

Mean motion resonance sometimes ensures the stable motions of the celestial bodies in multi-planetary systems. The resonant orbits provide a stabilizing mechanism for maintaining our solar system and extrasolar planetary systems. This paper focuses on the dynamical effect of eccentricity on the stability of the 3:5 external resonant orbits in the planar circular restricted three body problem (Star–Planet–Asteroid). We computed numerically the Poincaré section of this model. We found that the initial eccentricity of the asteroid has a significant effect on the stability of the resonant orbits. The topology of this Poincaré section changes three times with increasing eccentricity. With the help of the Poincaré section, we obtained some periodic, quasi-periodic, and chaotic orbits. We also plotted the resonant region in (θ, e, a) space. θ is the angular separation of the asteroid pericenter and the planet, and e and a are the eccentricity and semimajor axis of the asteroid, respectively.
Tree tensor network state approach for solving hierarchical equations of motion
Authors: Ke Yaling
Published: June 2023

The hierarchical equations of motion (HEOM) method is a numerically exact open quantum system dynamics approach. The method is rooted in an exponential expansion of the bath correlation function, which in essence strategically reshapes a continuous environment into a set of effective bath modes that allow for more efficient cutoff at finite temperatures. Based on this understanding, one can map the HEOM method into a Schrödinger-like equation, with a non-Hermitian super-Hamiltonian for an extended wave function being the tensor product of the central system wave function and the Fock state of these effective bath modes. In this work, we explore the possibility of representing the extended wave function as a tree tensor network state (TTNS) and the super-Hamiltonian as a tree tensor network operator of the same structure as the TTNS, as well as the application of a time propagation algorithm using the time-dependent variational principle. Our benchmark calculations based on the spin-boson model with a slow-relaxing bath show that the proposed HEOM+TTNS approach yields consistent results with those of the conventional HEOM method, while the computation is considerably sped up. In addition, the simulation with a genuine TTNS is four times faster than a one-dimensional matrix product state decomposition scheme.
Innovative all-organic dielectric composite for dielectric capacitor with great energy storage performance based on thermodynamic compatibility
Authors: Zhang Yue , He Xin , Li Sen , Zhang Changhai , Zhang Yongquan , Zhang Tiandong , Wang Xuan , Chi Qingguo
Published: June 2023

In modern electronics and power systems, good-performance dielectric capacitors have an essential function. Polymer-based dielectrics are widely used in the field of dielectric capacitors because of their large dielectric constant, flexibility, low density, and ease of processing. At present, ferroelectric polymers suffer from low breakdown field strength and high dielectric losses. How to improve the performance of dielectric materials in capacitors is still a promising research. This paper chooses the ferroelectric polymer poly(vinylidene fluoride) (PVDF) that worked as the matrix, and the linear polymers polyimide, cyanoethyl pullulan (CR-S), polyethersulfone, and cyanoethylated cellulose served as fillers. This all-organic dielectric composite produced as films working in electrostatic energy storage devices is prepared by using a casting method. Analyzing the test results, the composite film exhibited excellent electrical properties when the CR-S doping content was 5 wt. %. The organic composite dielectric based on CR-S/PVDF has a breakdown field strength of 450 MV/m, a discharge energy storage density (Ue) of 10.3 J/cm3, a high dielectric constant of 10.9, and a low dielectric loss of 0.004 at 1 kHz, which is a significant improvement compared with other dielectric composites. This all-organic dielectric composite strategy offers a new approach to achieve better-performance dielectric energy storage materials.
Structural, magnetic, mechanical, thermodynamic, and electronic properties of PuAlO3: A first-principles study
Authors: Li Xianqiong , Xie Xingyu , Shi Mingyang , Jiang Gang , Du Jiguang
Published: June 2023

Based on the Coulomb hybrid density functional with spin–orbit coupling (SOC) effect and generalized gradient approximation (GGA) + U method, the structural, magnetic, and electronic properties of PuAlO3 (Pnma and Imma) have been studied. The value of magnetic moment (μs) with the GGA + U method is maximum, the GGA + U + SOC method is minimum, and the GGA method is centered. The phonon curve of the two phases with ferromagnetic (FM) is almost identical to that of the antiferromagnetic (AFM) state. Pu atoms primarily contribute to the low-frequency phonon branches. In contrast, lighter O atoms are mainly responsible for the high-frequency phonon modes, and Al atoms are predominantly distributed in the middle part of the compound. For the mechanical properties, the volume modulus B of the V-R-H scheme agrees with the Birch–Murnaghan equation of state fitting results. Moreover, the bulk modulus is anisotropic, and the remaining parameters are isotropic. According to the electronic calculation, FM has a wider bandgap than AFM. In part of the state density diagram, it can be observed that the main contributors are Pu and O atoms. Bader charge calculation revealed that the charge of Pu and Al atoms transfers to O atoms.
Interference of sterile oat (Avena ludoviciana) and Mexican pricklepoppy (Argemone mexicana) in chickpea
Authors: Mahajan Gulshan , Chauhan Bhagirath Singh
Published: June 2023

Context Knowledge gaps exist for the interference of Avena ludoviciana and Argemone mexicana in chickpea grown in eastern Australia. Aims This research aimed to examine the effect of different interference levels of A. ludoviciana and A. mexicana for their potential to cause yield loss in chickpea. Methods Experiments were conducted in a randomised complete block design with five weed infestation levels of both weeds (none, low, medium, high, and very high) in three replications. Key results Infestations of A. ludoviciana and A. mexicana at 15 and 17 plants m−2 caused an 83 and 48% reduction in chickpea yield, respectively, compared with weed-free situations. Based on the regression model, a 50% yield reduction of chickpea occurred at 10 and 17 plants m−2 of A. ludoviciana and A. mexicana, respectively. Based on the modified hyperbolic model, maximum seed production of A. ludoviciana and A. mexicana in chickpea at an infestation level of 1 plant m−2 was estimated at 366 and 7800 seeds m−2, respectively. At crop harvest, seed retention of A. ludoviciana and A. mexicana was greater than 50 and 90%, respectively. Conclusions A. ludoviciana and A. mexicana infestation in chickpea caused a substantial reduction in crop yield. High seed retention in A. mexicana and A. ludoviciana in chickpea suggests the possibility to manage these two weeds through harvest weed seed control. Implications The information generated from this study could help in strengthening integrated weed management in chickpea.
Neutrophil extracellular traps and extracellular histones potentiate IL-17 inflammation in periodontitis
Authors: Kim Tae Sung , Silva Lakmali M. , Theofilou Vasileios Ionas , Greenwell-Wild Teresa , Li Lu , Williams Drake Winslow , Ikeuchi Tomoko , Brenchley Laurie ,   NIDCD/NIDCR Genomics and Computational Biology Core, Bugge Thomas H. , Diaz Patricia I. , Kaplan Mariana J. , Carmona-Rivera Carmelo , Moutsopoulos Niki M.
Published: June 2023

Neutrophil infiltration is a hallmark of periodontitis, a prevalent oral inflammatory condition in which Th17-driven mucosal inflammation leads to destruction of tooth-supporting bone. Herein, we document that neutrophil extracellular traps (NETs) are early triggers of pathogenic inflammation in periodontitis. In an established animal model, we demonstrate that neutrophils infiltrate the gingival oral mucosa at early time points after disease induction and expel NETs to trigger mucosal inflammation and bone destruction in vivo. Investigating mechanisms by which NETs drive inflammatory bone loss, we find that extracellular histones, a major component of NETs, trigger upregulation of IL-17/Th17 responses, and bone destruction. Importantly, human findings corroborate our experimental work. We document significantly increased levels of NET complexes and extracellular histones bearing classic NET-associated posttranslational modifications, in blood and local lesions of severe periodontitis patients, in the absence of confounding disease. Our findings suggest a feed-forward loop in which NETs trigger IL-17 immunity to promote immunopathology in a prevalent human inflammatory disease.
Shielding design aspects of SR in 3 GeV ILSF
Authors: Salimi Ehsan , Jalali Hamideh Beigzadeh , Esfandi Fatemeh
Published: May 2023

Iranian Light Source Facility (ILSF) is an under-construction synchrotron radiation accelerator consisting of a 150 MeV linac, a booster synchrotron operating from 150 MeV to 3 GeV, and a 3 GeV storage ring that stores a maximum of 400 mA current of electrons. As the stored beam circulates, a fraction of the beam is lost due to interactions with gas molecules, interactions among beam particles, and orbital bending, which produce radiation. The bulk shielding calculation for the ILSF and the input parameters used for this analysis are discussed in this paper. The potential of skyshine neutrons to cause radiation hazards is investigated as well. Moreover, the design and shielding simulation using the FLUKA Monte Carlo code is presented for the linac beam stop and primary and scattered gas bremsstrahlung for the first optics enclosure of the ILSF spectro microscopy beamline. Our designed radiation shielding system guarantees that the annual dose in all areas around the ILSF machine does not exceed the dose limit of 1 mSv.
Analytical model and simulation study of a novel enhancement-mode Ga2O3 MISFET realized by p-GaN gate
Authors: Yi Bo , Zhang Song , Zhang ZhiNing , Cheng JunJi , Huang HaiMeng , Kong MouFu , Yang HongQiang
Published: June 2023

In this paper, we propose a novel junction-less Ga2O3 metal–insulator–semiconductor field effect transistor (MISFET) with a p-GaN gate, named p-GaN Ga2O3-MISFET. A heavily doped thin layer p-GaN is set in the trench gate region to deeply deplete the n-Ga2O3 channel region owing to the high work function of the p-GaN. Thus, a high threshold voltage (V
TH) and breakdown voltage (BV) can be obtained even with a wide-fin design and low interface charge density (n
int), which ensures easy fabrication and a stable V
TH. Analytical modeling and experimentally calibrated technology computer aided design (TCAD) simulations confirm that with the increase of fin width (W
Fin) from 0.1 μm to 0.5 μm, the V
TH of the p-GaN Ga2O3-MISFET varies from 3.2 V to 2.4 V with n
int = −1 × 1011 cm−2, which is always about 2.2 V higher than those of conventional junction-less Ga2O3 MISFETs (CJL-MISFET). In addition, the BV of the CJL-MISFET decreases from ∼3400 V to ∼45 V with increasing W
Fin due to soft breakdown, while the BV of the p-GaN MISFET only decreases to 2800 V due to the enhanced electric field at the corner of the trench gate. Moreover, the activation energy and doping concentration (when larger than 3 × 1019 cm−3) of p-GaN barely affect the V
TH. Even so, a high V
TH remained in a common range of interface charge (from 1 × 1013 cm−2 to 2 × 1013 cm−2) at the p-GaN/Al2O3 interface.
PeV neutrinos of IceCube with very heavy fermion and very light scalar
Authors: Fan Zhao-Xing , Li Qin-Ze , Liu Chun , Reyimuaji Yakefu
Published: June 2023

A new physics scenario to explain PeV neutrinos observed in the IceCube experiment is introduced, with dark matter and dark energy considered. A slowly decaying very heavy fermion with a PeV mass as the dark matter particle is the origin of the PeV neutrinos. They couple to an extremely light field and this light field constitutes the dark energy.
Ultrafast antiferromagnet rearrangement in Co/IrMn/CoGd trilayers
Authors: Guo Zongxia , Malinowski Gregory , Vallobra Pierre , Peng Yi , Xu Yong , Mangin Stéphane , Zhao Weisheng , Hehn Michel , Zhang Boyu
Published: June 2023

Antiferromagnets offer great potential for high-speed data processing applications, as they can expend spintronic devices from a static storage and gigahertz frequency range to the terahertz range. However, their zero net magnetization makes them difficult to manipulate and detect. In recent years, there has been a lot of attention given to the ultrafast manipulation of magnetic order using ultra-short single laser pulses, but it remains unknown whether a similar scenario can be observed in antiferromagnets. In this work, we demonstrate the manipulation of antiferromagnets with a single femtosecond laser pulse in perpendicular exchange-biased Co/IrMn/CoGd trilayers. We study the dual exchange bias interlayer interaction in quasi-static conditions and competition in ultrafast antiferromagnet rearrangement. Our results show that, compared to conventional ferromagnetic/antiferromagnetic systems, the IrMn antiferromagnet can be ultrafast and efficiently manipulated by the coupled CoGd ferrimagnetic layer, which paves the way for potential energy-efficient spintronic devices.
Interannual and decadal variations of the Kuroshio axis in the East China Sea
Authors: Zhang Xiaoshuang , Wang Bin , Wang Xidong , Zhu Xiande , Wu Baoqin , Sun Chunjian
Published: June 2023

Much work has been focused on the variability and climatic effect of the Kuroshio Extension, but little focus on the Kuroshio variation in the East China Sea(ECS). This study, investigates the interannual and decadal migrations of Kuroshio axis(KA) in the ECS and its relationships to large-scale climate signals. On interannual timescale, variability of the KA in the ECS is closely related to El Niño-Southern Oscillation (ENSO) cycle. The shifting of the main axis in ECS presents a dipolar pattern with the offshore (onshore) shift of the south (north) part KA in ECS under the El Niño events and onshore (offshore) shift under the La Niña events. The interannual variation (IVAR) is modulated dominantly by wind stress curl (WSC) and surface relative vorticity advection associated with the ENSO. On the decadal timescale, the Pacific Decadal Oscillation (PDO) and North Pacific Gyre Oscillation (NPGO) could cause the WSC and relative vorticity (RV) anomalies, and in turn modulates the fluctuation of KA. The PDO is the main factor and the NPGO is secondary factor for the decadal variation (DVAR) of the KA in ECS.
Climatology of Tropical Cyclone Intensity Landfalling on Luzon Island and China
Authors: Zhang Shuqin , Huang Zhefan , Zheng Yanzhu , Xue Yufeng , Tang Ruoying , Shi Yifan , Yang Wanqiong , Wang Zongyang
Published: June 2023

Using the TC best path data and the ERA5 reanalysis data, the statistical characteristics and environmental conditions for three types of TCs landfalling on Luzon Island and China during 1949-2020 (72 years) are investigated in this work. According to the intensity change before and after landing on Luzon Island, it can be divided into three types of TCs: “Weakening” TCs (40.0 %), and “Unchanging” TCs (33.6 %), and “Enhancing” TCs (26.4 %). The “Weakening” TCs had similar landing frequency in summer and autumn, stronger strength, longer lifespan and most of that landfalled on China with the northwest or westward track. The “Enhancing” TCs and “Unchanging” TCs occurred mostly in summer, their track were most of the westward track. The “Enhancing” TCs had the weakest strength and the shortest lifespan. It is found that the weakening effect of topography of Luzon Island to the TCs was greater than the strengthening effect. The precipitation of “Weakening” TCs was much greater than that of the other two types of TCs. And lower SST, the “Ventilation Flow” effect caused by topography of Luzon Island and abated water vapor transport were not conducive to the development of “Weakening” TCs. On the contrary, the higher SST and more weaken central VWS of “Enhancing” TCs provides favorable thermal and dynamic conditions for their development, moreover water vapor transport strengthen provided favorable moisture conditions. Affected by the convergence of topography of Luzon Island arose in three types of TCs were the greatest precipitation during landing on Luzon Island.
Experimental and observational analysis of vertical characteristics of internal solitary waves
Authors: Peng Pai , Du Hui , Wei Gang , Wang Shaodong , Xuan Pu , Xu Junnan , Cai Shuqun
Published: June 2023

The basic elements of internal solitary waves (ISWs) were obtained by vertically placed sensors in the laboratory experiment and in-situ observation. The vertical characteristics of the amplitude and waveform are analysed experimentally and observationally. Then the experimental and observational results were compared with the theoretical model. The study shows that the experimental amplitude-frequency relationship is closer to that in the two-layer model while the observational amplitude-frequency relationship is more approaching to that in the continuously stratified model. Experimental and observational results reveal that the amplitude of ISWs increase first and then decrease with an increasing depth. The sech2 function of the KdV theory can describe the waveforms of ISWs at different depths well.
Temporal and Spatial Variation Characteristics of SST in the North Pacific Ocean in Summer
Authors: Zhang Yun-xiang , Hong Mei , Shi Jian , Wu Xin-jie , Guo Zi-long
Published: June 2023

Using Hadley Centre Sea Sea Surface Temperature data in the North Pacific region (0°N~60°N, 120°E~80°W) from 1950 to 2017, based on Empirical orthogonal function(EOF) analysis, the multi-year spatio-temporal field of SST in the North Pacific Ocean in summer into three main modes is decomposed into three modes. The temporal and spatial variation characteristics of SST in the North Pacific summer (June to August) are discussed in detail. The results show that the spatial distribution and time series of the first mode can reflect ENSO signal well. Compared with the first mode, the spatial field of the second mode has an inverse phase distribution. The spatial field distribution of the third mode is similar to the zonal distribution, and the whole sea area presents an oscillating structure of alternating cold and warm regions from south to north.
A modified sea ice area empirical prediction model based on multi-source satellite remote sensing data for Liaodong Bay of the Bohai Sea, China
Authors: Chen Xiaoyu , Wei Dongni , Wang Xifeng
Published: June 2023

Liaodong Bay is located in the north of the Bohai Sea, China. It experiences ice conditions of different degrees every year for about 3 months. Accurate prediction of sea ice area is of great significance for various marine activities. An empirical models based on the cumulative freezing temperature and cumulative melting temperature have been proposed in the past studies. This model can well describe the freezing and melting trend during each ice age, but it lost its accuracy for the prediction of short-term drastic change of sea ice area. In the present study, a modified empirical model considering sea surface temperature and wind besides cumulative freezing temperature and cumulative melting temperature is proposed. The coefficients of the modified model are fitted by the matched sea ice area of Liaodong Bay extracted from the multivariate satellite remote sensing images and the hydro-meteorological data from 2015, 2016, 2018 and 2019, while the data of 2020 are used for verification. Results show that the modified model can better adapt to the dramatic changes of sea ice area caused by short-term weather processes. The average absolute error is 685.71 km2 and the relative error is 23%. Finally, the influence of sea ice area on the time lag of temperature response and other factors such as water depth are discussed.
Spatio-temporal characteristics of global maritime ship casualties
Authors: Li Jian , Liu Haiyang , Zhang Wei , Huang Quanyi
Published: June 2023

Maritime transportation safety of ships is important for international trade. Analyzing the spatio-temporal characteristics of global maritime ship casualties is the basis for maritime ship traffic planning, risk assessment and prevention. Based on the global maritime ship casualty data from 2000 to 2019, the number of the ship casualties were count by detailed event type, year, and month. Kernel density estimation of four periods were carried out. Sea areas around the English Channel, and the Aegean Sea were the hotspots from 2000 to 2019. The Korea Strait, Gulf of Saint Lawrence, Gulf of Alaska, Malacca Strait, and sea areas near Shanghai were also the hotspots in some of the four periods from 2000 to 2019.
A High Precision Tidal Model Based on Multisource Tidal Harmonic Constants for Offshore China
Authors: He Weiwei , Wang Qijie , Zhang Huayi , Wang Mengrui
Published: June 2023

As the accuracy of analytical instruments improve, the accuracy of ocean tide load displacement (OTLD) in geodesy and ocean dynamics is becoming increasingly demanding. The method of integrating through the load Green’s function using the ocean tide model is the main means of OTLD correction. However, although different tidal models have high accuracy in open ocean regions, they are less precise and less practical in the offshore areas of China, making it difficult to correct OTLDs accurately in complicated coastline areas of China. In this work, we evaluate the accuracy of 13 different tidal models in offshore China, and construct a new tidal model, new.chinasea.2022, based on the combination of high-precision tidal harmonic parameters. The OTLD correction efficiency of new.chinasea.2022 and conventional tidal models was assessed by wRMS analysis of GPS coordinate time series from the Crustal Movement Observation Network of China (CMONOC). It turns out that (1) the newly released tidal model performs better than the old model in offshore China, and there are differences in the performance of different models for each tidal constituent in different seas; (2) The OTLD correction of new.chinasea.2022 performed better in the offshore region of China, improving the correction of FES2004 by 1%-12% and osu.chinasea.2010 by 1%-6.5%.
Evaluation of the global ocean forecast system in NMEFC with the IV-TT class4 metrics
Authors: Mo H E , Qin Y H , Zu Z Q , Zhang Y
Published: June 2023

Based on the IV-TT Class4 metrics, this paper comprehensively evaluates the forecasting performance of the National Marine Environment Forecast Center High-resolution Global Ocean Forecasting System (hereinafter referred to as NMEFC-NEMO) on sea surface temperature (SST), sea level anomaly (SLA) and temperature-salinity profiles. The RMSE of NMEFC-NEMO for SST and SLA over forecast length has the smallest error among the international operational systems, which are 0.45°C and 0.07m, respectively. The forecast accuracy of NMEFC-NEMO temperature and salt profile RMSE is in the middle among the operational systems, with the values of 0.69°C and 0.24 PSU. In the profile forecast, the error of NMEFC-NEMO is slightly larger than other systems at 50-100 m depth, which is related to the fact that NMEFC-NEMO does not assimilate ARGO temperature and salinity directly. In addition, with respect to the forecast skill scores, NMEFC-NEMO has a positive climatology skill scores for both SST and SLA, and the persistence skill scores for SST is better than that for SLA.
Inter-comparison of global ice sea coupling model based on NEMO and MITgcm
Authors: Liu Xin , Zeng Chongji , Yin Tienan , Wang Zhaoyi , Li Zhijie , Yao Zhongyuan , Zhang Yu , Yan Qihui
Published: June 2023

Two global high-resolution ice sea coupling model established on basis of NEMO and MITgcm were systematically evaluated, by comparing the climatology simulation results of their sea surface temperature, sea surface salinity, sea surface current and sea ice area with SODA3, EN4, and NSIDC. The simulation accuracy of each element in the global and typical sea areas are quantitatively evaluated. The global RMSE of SST modeled by NEMO and MITgcm are 0.38°C and 0.46°C, respectively. NEMO had lower SST RMSE in strong current areas, especially in Kuroshio and Antarctic circumpolar currents, while MITgcm had better SST simulations in low-middle latitudes and most of Arctic Ocean. The global RMSE of SSS of NEMO and MITgcm is 0.47psu and 0.69psu, and the highest RMSE of SSS of the two models are in the Arctic Ocean. The RMSE of NEMO and MITgcm on surface current simulations are 0.0465m/s and 0.0474m/s, and both NEMO and MITgcm have high RMSE in their simulations of strong currents. The sea ice area simulated by NEMO and MITgcm are basically the same as that of NSIDC in spatial morphology, and the absolute value of the relative error of sea ice area in the Antarctic and Arctic of the two models are within 25%. The inter-comparison and evaluation results provide a reference for the product application and the model improvement of the two high-resolution ice sea coupling models.
Development of the Operational Oceanography Forecasting System in the Northwest Pacific
Authors: Wang Zhaoyi , Liu Guimei , Li Wei , Wang Hui , Wang Dakui
Published: June 2023

An operational oceanography forecasting system is established on the base of ROMS and data assimilation method to provide operational predictions and maritime safety applications for the Northwest Pacific. After 10 years spun up through integration, the system reaches a stable field of annual circulation. The model was then integrated from 1990 to 2012 to obtain the assimilation background. After the evaluation of observation data, the ocean forecasting system has been put into operation since 2013 and has been updated for several times. Through the validation of 2018, the system can accurately simulate the main marine environmental characteristics of the northwest pacific. The system can provide high-resolution marine environment fields for red tide, green tide drift and diffusion, oil spill, marine fishery, marine resources development, marine search and rescue, etc.
Numerical simulations on waves in the Northwest Pacific Ocean based on SWAN models
Authors: Jialei Lv , Jian Shi , Wenjing Zhang , Jingmin Xia , Qianhui Wang
Published: June 2023

Waves are one of the most important dynamic phenomena in the ocean, and thus numerical simulations of ocean wave is of great importance. Based on SWAN wave numerical model, this paper simulates the waves in the Northwest Pacific Ocean and analyzes the wave height field in the sea area. Moreover, A new wave period parameterization scheme is proposed according to the relationship between the wave height and wave period, in addition, the simulation mode of wave period elements in the Northwest Pacific Ocean is optimized by analyzing the difference of wave period under the proposed parameterization scheme.
Impact of Hydrodynamic and Suspended Sediment on Liyashan Oyster Reef
Authors: Yang H. B. , Wu H. B. , Chen F. , Chen Z. P.
Published: June 2023

Based on the sensitivity of oysters to water environmental factors, a hydrodynamic model in Tongzhou Bay, southwest of China’s Yellow Sea, is set up to analyse the impact of the hydrodynamic and suspended sediment on the Liyashan Oyster Reef. The results show that the hydrodynamic characteristics of the waters near the oyster reef will not be significantly affected by the implementation of the project. The diffusion range of suspended sediment concentration greater than 10mg/L caused by channel dredging will not reach and affect oyster reef area, and the growth of oysters will not be significantly affected by Tongzhou Bay Channel Construction.
Analysis of Characteristics of Tide and Tidal Current in the east China Seas
Authors: Wang Ning , Gao Yuan , Guo Hailong , Lu Jiaqing
Published: June 2023

The features of tide and tidal current in the east China seas were studied by the FES2014 tide data and tide gauge station data. It is found that FES2014 data is in well agreement with the observation. Among the four major tidal components (M2, S2, K1, and O1), M2 is the strongest tidal component with the maximum amplitude (tidal current) exceeds 100 cm (100 cm/s), followed by S2 tide with its maximum amplitude (tidal current) reaches 60 cm (50 cm/s). The results indicate the east China seas are dominated by semi-diurnal tides. There are four amphidromic points for semi-diurnal tides, and two amphidromic points for diurnal tides. Rotating tidal current dominates the areas far from the coast, and rectilinear current dominates the coastal sea area. The strong tidal currents are often distributed in some places with special topography such as bays and estuaries.
The Effect of Storm Surge on Three-dimensional Tidal Current Characteristics: A Case Study of “Lekima”
Authors: Wang Y. , Luo F. , Zhang Y. F.
Published: June 2023

This study simulated the process of storm surge in the Eastern China Sea (ECS) during typhoon Lekima, based on the MIKE3 wind-surge model driven by the reconstructed typhoon wind field, which was calculated by the Holland empirical formula. The results show that, affected by shoreline and topography, the storm surge in the Hangzhou Bay and the Taizhou Bay can be more than 3.0 m during typhoon Lekima. During the typhoon, the maximum storm surge on the right side of the track was relatively larger than that on the left side, especially along the coast. And the value of maximum current speed was more than 2.5 m/s, which can be obtained in the coast of Zhejiang. The storm current speed at stations presented logarithmic distribution along the depth generally, either the astronomical tide or storm tide. The vertical structure of current velocity responded to typhoon Lekima presented obvious layered distribution. The value of current speed inner the layers was more than that in the side of the layer.
Numerical model for interactions between shallow water wave and continuous submerged porous structures
Authors: Wang Guangsheng , Yang Yunhan , Zhang Hongyan , Sun Chaoyang , Tao Aifeng , Sui Titi
Published: June 2023

Submerged porous breakwater in shallow estuarine environments is considered to have the potential to provide shoreline protection as well as offshore structures. The research aims to address how submerged porous structures can effectively attenuate wave energy in shallow waters. In this paper, the wave generation library waves2Foam is used to generate waves. A series of numerical experiments are conducted taking into account different physical parameters of porous structures and wave factors.
A Shifted Double Wavelet Iteration Algorithm for Detecting the Gross Errors in Shipborne Gravity
Authors: Wang X. , Fan J. Y. , Deng K. L. , Chen X.
Published: June 2023

Detecting the discrete gross error and regional gross error in shipborne gravity is a key step for improving the measurement quality. The traditional wavelet threshold shrinkage (WTS) method misidentifies discrete gross errors and cannot detect regional gross errors. Here we propose a shifted double wavelet iteration (SDWI) method. This method decomposes the measurement sequence by shifted double wavelet to obtain wavelet coefficients, and then apply threshold processing to the obtained coefficients to accurately detect gross errors. After that, we reconstruct the identified gross errors, and perform iterative processing to the regional gross errors. Finally, the difference of the gravity before and after gross error detection is used for gross error positioning. In the simulation experiment, we use the proposed SDWI method to detect the discrete gross error, the regional gross error and discrete-region gross error in the shipborne gravity, separately. The results show that the detection success rate is 100% and failure rate is 0 for all three kinds of gross errors, better than that of the traditional WTS method. The real data experiment also confirms that the proposed method is effective in detecting gross errors.
Compensation of UUV magnetic field interference based on ridge estimation
Authors: Zhang R , Zhang Q , Hu J , Pan M , Luo H , Li Z , Ding Z , Liu J , Du Q
Published: June 2023

The ocean magnetic anomaly detection based on unmanned underwater vehicles has great significance in military field, such as anti-submarine, anti-mine, and ship magnetic property evaluation. But it is easy for magnetometer fixed on vehicles to be affected by the magnetic interference of vehicles ferromagnetic equipment and electronic equipment. The magnetic interferential field seriously affects the measurement accuracy of the magnetometer. In this paper, ridge estimation method is proposed to estimate magnetic field interference coefficient and compensate magnetic field. A simulation is conducted to verify the validity of the method. And an experiment is designed and implemented on a vehicle. This method can reduce the measurement error of the magnetometer from 11000.0nT to 155.6nT and compensate 98.55% of the magnetic field interference. Both of simulation and experimental results show that ridge estimation method can effectively overcome the influence of complex collinearity of data and better compensate the interference magnetic field.
Impact of Evaporation Duct on Line-of-sight Propagation of Electromagnetic Waves
Authors: Yang F , Yang K-D , Shi Y , Wang S-W , Zhang H , Zhao Y-M , Hu D-W , Dong G-Y
Published: June 2023

Generated by the evaporation of seawater, evaporation duct (ED) is an air-sea interaction that occurs over the sea surface. The electromagnetic (EM) waves will be trapped in ED when propagating beyond line-of-sight. However, the impact of ED on line-of-sight propagation is rarely reported. The path loss (PL) oscillates within the first few kilometers when the EM wave propagating in line-of-sight and then greatly reduced. Simulation results shown that the PL in ED layer can be reduced by more than 40 dB on line-of-sight propagation. The experiment PL selected from the South China Sea in March 2022 is 28.2 dB lower than the simulation PL in standard atmosphere, which verifies the conclusions. The conclusions contribute to the design and use of marine radar and communication systems.
Magnetic Field Feature Fusion of Underwater Vehicle Model Based on Principal Component Analysis
Authors: Hu Ping , Chen Sidi , Jiao Dawen , Qi Jiahui
Published: June 2023

Aiming at the model of underwater vehicle, a magnetic field feature fusion method based on principal component analysis (PCA) is proposed, focusing on: Non-stationary, nonlinear and non-Gaussian magnetic field time domain of underwater vehicle model based on genetic algorithm optimization neural network Feature extraction technology, underwater vehicle model fusion technology based on principal component analysis of magnetic field time-domain features, constructs effective PCA fusion features with low dimension, and finally uses the model sample recording data to conduct experiments on the main methods of this paper Verification and experimental simulation results show that PCA fusion features can reduce the feature dimension on the basis of maintaining a sufficient amount of effective information, and improve the target recognition efficiency. The results confirm the effectiveness of the related algorithms.
Comparing the spatial domain and frequency domain algorithms for upward continuation of marine magnetic anomaly
Authors: Xiong X , Deng K L , Wu T Q
Published: June 2023

Space potential field continuation is a method frequently used for the spatial transformation of magnetic anomaly in the sea area, and is the key technology for constructing three-dimensional marine magnetic field model and the application of marine magnetic survey data. In this study, we analyze the principle of upward continuation of potential field from plane to plane, demonstrate the spatial domain algorithm and frequency domain algorithm, and propose the standards for evaluating the accuracy of the two algorithms. Using the theoretical data of the multi-dipole sphere model, we employ the two algorithms to continue the magnetic anomaly of the observation plane at the height 0 m to 100 m, 200 m, and 300 m, for noisy and noise-free conditions. The results show that the continuation error of the two methods is extremely small at the plane center, but large on the edge; the spatial domain algorithm has obviously better accuracy than the frequency domain algorithm, so it should be preferentially selected in high-precision applications, such as magnetic anomaly detection in the sea area.
Research on the Architecture of Underwater Acoustic Environment Common Operational Picture in Joint Operation
Authors: Li Y Y , Zhou Y X
Published: June 2023

With developing of information warfare, the environmental services make more and more significant effect for situational awareness and decision superiority in Integrated Joint Operation. As the mainly environmental factor of sea battlefield, the underwater acoustic environment has an important influence for the capability of sonar detecting and undersea weapon attacking. In this paper, a serving architecture of Underwater Acoustics Environment Common Operational Picture (UAE-COP) in Joint Operation for underwater acoustic environment is proposed, which includes systematic frame, information content, simulating models, technologies, and so on. Computer simulation and typical application shows that the proposed structure will be a valuable mode for underwater acoustic environment tactical decision support.
Passive Velocity Estimation of a Distant Harmonic Source in a Pekeris Waveguide Based on Modal Doppler Shifts
Authors: Cui Hongxu , Li Xiaolei , Gao Wei
Published: June 2023

The acoustic field generated by a moving point source in terms of normal modes predicts that each mode has a different Doppler shift, i.e., modal Doppler shifts, which contains the velocity information of the moving source. This paper presents a method to estimate the velocity of a distant harmonic source in a Pekeris waveguide passively based on modal Doppler shifts. Combined with the fact that the modal depth function varies slowly with frequency, a cost function is designed to realize the velocity estimation of a distant harmonic source with a single hydrophone when the bottom parameters are unknown. The effectiveness of the method is validated by simulations.
Deep-sea explosion sound signal propagation loss measurement and model verification
Authors: Tian He , Chen Jiandong
Published: June 2023

This paper researched the low-frequency sound field propagation characteristics in the continental slope sea area, the sound field propagation loss is calculated by using the radiated sound field data of the deep-fixed explosive sound sources with 50 m and 200 m depth in the continental slope sea area, and the experimental results are verified by combining with the Kraken normal wave model. The model verification results are in good agreement with the experimental measurement data.
Track Detection of Underwater Moving Targets Based on CFAR
Authors: Zhang Haoting , Tian Mei , Ouyang Qicheng , Liu Jingjing , Shao Gaoping , Cheng Juan
Published: June 2023

In this paper, we propose a 2D-Weibull-Constant False Alarm Rate (2D-Weibull-CFAR) detection algorithm to solve the problem that detecting current underwater targets is difficult due to the influence of reverberation noise. Specifically, referring to the idea that CFAR uses the probability distribution of reference units to detect objects, this paper introduces the pixel distribution of reverberation noise into the CFAR detector. After that, the probability distribution of the extracted reference units is estimated, and then the adaptive detection threshold is obtained to achieve reliable detection of underwater targets. Finally, the Hough transform extracts the trajectory of the detection results. The experimental test shows that the algorithm in this paper can solve the problem of false alarms and missed alarms in detecting targets hidden in the reverberation noise. The algorithm in this paper can effectively detect the target in the reverberation noise. The detection results show that the algorithm in this paper has higher accuracy and lower false alarm rate than the comparison algorithm.
Interference-LOFIX: A Passive Localization Method for a Target Near the Water Surface
Authors: Zong Shutong , Li Xiaolei , Gao Wei
Published: June 2023

Low Frequency Analysis and Recording Fixing (LOFIX) is a conventional method for localization of underwater target using multiple omnidirectional passive sonobuoys. The key of LOFIX is the relationship between the received signal strength of each sonobuoy and the target-sonobuoys distance. However, the fluctuation of the sound field deduced by the ocean environment often degrades the performance of LOFIX significantly. To solve this problem, a new localization method based on the interference characteristics of the sound field excited by the sound source near the water surface is presented in this paper. Numerical simulations and lake experiment verify the effectiveness of our presented method.
Fast Track Smoothing Algorithm for Underwater Target Tracking Based on KD Tree
Authors: Qi Bin , Tian Jin , Wang Jinjin , Liang Guolong
Published: June 2023

A fast-track smoothing algorithm based on the KD Tree is proposed to address the problem of state estimation in underwater multi-target tracking. For multi-target tracking, the multi-Bernoulli filter becomes intractable due to the high-dimensional nature of the posterior. This problem can be overcome by the particle filter (PF), which approximates the posterior by a set of weighted samples (“particles”). The probability distribution of the multi-Bernoulli algorithm based on this algorithm contains a series of particles with weights. Therefore, while smoothing it, the state transfer probability of each particle must be computed, and the state transfer function must be calculated, which is related to the difference in states between the k-1 moment and the k moment, we refer to this difference as the state distance. However, the KD Tree can be used to divide the particle set into different state spaces according to the particle states, and thus calculate the state distances more efficiently. The remarkable feature of this algorithm is that the time complexity is greatly reduced from that O(N2) of the traditional algorithm to O(NlogN). This paper implements the proposed method using particles, the improved algorithm based on KD tree effectively mitigates the disadvantages of previous forward-backward smoothing algorithms, and significantly reduces the computation time while improving the system state estimation precision. Experimental results of simulation analysis and the optimal sub-patten assignment distance is employed as an assessment criterion to validate the algorithm’s performance.
Frequency Estimation with Co-prime DFT Filter Bank and Half Nyquist Frequency Shift
Authors: Zhang Xueyan , Qu Libin , Niu Shuai
Published: June 2023

When processing wide sense stationary (WSS) signals, the sampled data rate of conventional MN bands DFT filter bank is at least MN, while the co-prime DFT filter bank (co-prime DFTFB) only needs M+N, that sharply lowers the sampling rate. Here, M and N are co-prime pair of integers. However, practical FIR filter imperfections and correlation detection mode arouse spurious peaks in signal power spectrogram, that greatly limits the application of co-prime DFTFB. In this paper, we propose a modified co-prime DFTFB by adding a real valued multiplier to the original one, where M and N are both odd numbers. Together with original co-prime DFTFB, we get a 2MN bands filter bank. In the simulation section, two BPSK signals with random carrier frequencies are employed. The results of detection probability versus SNR curves through 500 Monte Carlo experiments verify the effectiveness of our method.
A Scaled Tank Experiment for the Stochastic Rough Interface Scattering
Authors: Zhou Zhen , Gao Bo , Pang Jie
Published: June 2023

Bottom reverberation is an important limitation that affects the detection performance of active sonar in shallow water. The stochastic rough seafloor surface scattering is one of the main scattering sources of the bottom reverberation. Since there are much uncertainties, such as propagation fluctuation, unstable station of transmit and receive equipment, it is difficult to investigate the quantitative relationship between the random rough interface parameters and the statistical property by processing the experimental reverberation data collected in the ocean In this paper, the statistical characteristics of the irregular 3D printed interface scattering field are studied by a scaled tank experiment, and the detailed results are presented by the comparison between the COMSOL simulations and the recorded data, the feasibility of the random rough interfaces experiment is verified well. Because the relationship between parameters is precisely controllable, it lays a foundation for the subsequent experimental research of target extraction under the background of interface scattering.
Study on the method of passive ranging for the moving target underwater without prior knowledge of the marine environment
Authors: Tang W L , Han K F
Published: June 2023

The waveguide invariant is used to describe the relationship between the slope of interference fringes, the frequency and the distance of the source in the frequency-distance acoustic intensity diagram. The waveguide invariant method considers the influence of the channel environment on sound propagation and reduces the dependence on environmental parameters, which makes its robustness stronger. In this paper, the ranging algorithm using a single element is discussed without considering the information of waveguide environment parameters. Based on the horizontal hydrophone array, the array signal processing method is used to improve the accuracy of ranging compared to a single element. The experimental results show that the ranging accuracy of this method is improved to less than 2% at a long distance after the conventional beamforming (CBF) processing. The above results show that the array signal processing method used improves the accuracy of the distance measurement obviously.