bluuebunny/crossref_metadata_2025 huggingface dataset:
Ionic wind generation through coplanar discharge: A plasma actuator without exposed electrodes
Authors: Sato Shintaro , Sakurai Mahoro , Ohnishi Naofumi
Published: June 2023

This study demonstrates the successful induction of a unidirectional ionic wind by adding an embedded electrode in a coplanar discharge, thus breaking the generation of a symmetrical electric field. The strategy for the ionic wind generation is based on separating the ionization process and the charged-particle acceleration process. Conventional plasma actuators used to induce an ionic wind typically incorporate exposed electrodes that pose a risk of unexpected airflow disturbance and reduce durability due to oxidation. However, the coplanar discharge-based, exposed-electrodeless plasma actuator developed in this study overcomes these issues. The coplanar discharge generates a diffused and uniform surface discharge, a desirable attribute for plasma actuators. The ionic wind velocity generated by this coplanar discharge plasma actuator is comparable to that generated by conventional plasma actuators when applying a square-waveform bias voltage to the additional electrode. Furthermore, this study emphasizes the significance of the phase difference between the repetitive pulses for generating coplanar discharge and the square-waveform voltage for accelerating the charged particles.
Stefan problem coupled with natural convection: An application to dissolution process
Authors: Nandi Subhankar , Yedida Sanyasiraju VSS
Published: June 2023

This paper investigates the process of dissolution of a solute in a solvent placed in an horizontal concentric cylinder. The theoretical investigation solves a Stefan problem with phase transition due to natural convective flow. To realize the objective, the governing equation for the concentration distribution, stream function–vorticity form of the Navier–Stokes equation for the flow field, and a Stefan condition for calculating the timescale evolution of the front are coupled together with different parameters. These non-linear equations are solved using a stable and second-order accurate boundary-fitted alternating direction implicit scheme with first-order upwind difference approximation for convective terms. The numerical scheme is validated initially by applying it to solve a natural convection problem with no phase transition, for which benchmark solutions are available. The validated scheme is then applied to the chosen problem followed by a refinement study to obtain a reliable solution. The obtained results are used to analyze the effect of physical parameters such as the Stefan number (Ste), geometric aspect ratio of solute to fluid, the Rayleigh number (Ra) and the Schmidt (Sc) number on dissolution rates as well as the flow patterns. It is observed that the solute dissolution, without the temperature influence, mainly depends on the annulus gap width (L) and the convection rate. Additionally, it is also observed that, for the Rayleigh numbers greater than 105, the unit circular-shaped solute initially dissolves uniformly from the outer surface, but as the time progresses, due to the influence of laminar boundary layer flow around the solute, it changes into an egg-shape.
A two-phase density-based solver for simulating wet steam flows with non-equilibrium condensation. II. Effects of 3D surface topography through nozzles
Authors: Luo Mengqiong , Lu Shun , Zhu Qingyong
Published: June 2023

In Paper I, we developed a new two-phase flow solver and assessed its reliability and effectiveness through a series of numerical simulations. In Paper II, we utilized this solver to study the steam flow through nozzles characterized by three-dimensional surface topography. To generate random rough surfaces, we employed a multivariate Weierstrass–Mandelbrot function. Our numerical simulation results exhibited good agreement with the reported experimental data for pressure distribution. Moreover, we examined the changes in pressure, temperature, humidity, Mach number, average Nusselt number, and thrust as the wall surface morphology varied. We observed that the pressure field was prone to fluctuations, the boundary layer structure thickened and changed, the degree of condensation decreased with reduced humidity, three-dimensional Mach waves occurred, and the averaged Nusselt number decreased while thrust deviation increased. These findings contribute to a better understanding of the effects of fractal dimensions and condensation on random roughness in steam flow through nozzles and highlight the significance of incorporating surface topography into numerical simulations to improve accuracy and predictability in engineering applications.
Surface tension of binary and ternary mixtures mapping with ASP and UNIFAC models based on machine learning
Authors: Deng Jiandong , Zhang Yanan , Jia Guozhu
Published: June 2023

Modeling predictions of surface tension for binary and ternary liquid mixtures is difficult. In this work, we propose a machine learning model to accurately predict the surface tension of binary mixtures of organic solvents-ionic liquids and ternary mixtures of organic solvents-ionic liquids–water and analytically characterize the proposed model. In total, 1593 binary mixture data points and 216 ternary mixture data points were collected to develop the machine learning model. The model was developed by combining machine learning algorithms, UNIFAC (UNIversal quasi-chemical Functional group Activity Coefficient) and ASP (Abraham solvation parameter). UNIFAC parameters are used to describe ionic liquids, and ASP is used to describe organic solvents. The effect of each parameter on the surface tension is characterized by SHAP (SHapley Additive exPlanation). We considered support vector regression, artificial neural network, K nearest neighbor regression, random forest regression, LightGBM (light gradient boosting machine), and CatBoost (categorical boosting) algorithms. The results show that the CatBoost algorithm works best, MAE = 0.3338, RMSE = 0.7565, and R2 = 0.9946. The SHAP results show that the surface tension of the liquid decreases as the volume and surface area of the anion increase. This work not only accurately predicts the surface tension of binary and ternary mixtures, but also provides illuminating insight into the microscopic interactions between physical empirical models and physical and chemical properties.
Engineering structural homogeneity and magnetotransport in strained Nd2Ir2O7 films
Authors: Song Jeongkeun , Ko Eun Kyo , Lee Sangmin , Mun Junsik , Jeong Ji Hwan , Lee Jong Hwa , Kim Woo Jin , Kim Miyoung , Li Yangyang , Lee Ji Hye , Noh Tae Won
Published: June 2023

The 5d pyrochlore iridate family (R2Ir2O7, where R is a rare earth ion) has garnered significant attention due to its topological properties, such as Weyl semimetallic phases and axion insulator. However, the investigation of these properties has been impeded by severe iridium loss during growth, which results in the formation of defects and impurities. Herein, we demonstrate a method for controlling impurities and defects in strained Nd2Ir2O7 (NIO-227) films by compensating for iridium loss during growth. By increasing the amount of IrO2 target ablated, we enhance the morphological quality and electrical transport properties of the fabricated films. Furthermore, our results show that the anomalous Hall effects of the films have a strong dependency on the amount of IrO2 target ablated, which is attributed to the structural inhomogeneity in the NIO-227 films. Our work provides a way to control defects and impurities and would promote the investigation of topological phases in the family R2Ir2O7.
A family of two-dimensional conductors comes into bloom
Authors: Miller Johanna L.
Published: June 2023

MXenes, a promising group of atomically thin materials, can now be fabricated without harsh acids and with little waste.
World-leading rare isotope facility is on line in Michigan
Authors: Feder Toni
Published: June 2023

Ion beams from oxygen to uranium contribute to research for applications and fundamental nuclear science at a new DOE user facility.
Nanophotonics for a sustainable future
Authors: Dionne Jennifer A. , Dagli Sahil , Shalaev Vladimir M.
Published: June 2023

As the field matures, its researchers are finding practical applications in solar-energy harvesting, chemical manufacturing, optical refrigeration, and energy-efficient computing.
Making soft and reconfigurable electronics with liquid metals
Authors: Awartani Omar , Dickey Michael D.
Published: June 2023

Gallium-based alloys can change shape when an electric potential reversibly alters its surface tension.
Teaching eco-translation
Authors: Kölling Angela , Lieb Melina
Published: June 2023

The coronavirus pandemic has kept us individually as well as publicly in a state of preoccupation that prohibited
us from staying with the trouble of an ecologically damaged planet. The authors of this contribution are sharing their experience
and reflections upon teaching, as an active intervention to this absent presence in everyday Covid-19 lives, an eco-translation
course. For this we will first offer a short discussion of our scholarly backgrounds and biases. Second, we will describe our
efforts in translating these biases into concrete teaching. The course that serves here as a case study was taught in a project
format in the 2021 winter term 2 at the Faculty for Translation Studies, Linguistics and Cultural Studies at Mainz University. It
was a five-day course which blended localisation and nature writing framed by a holistic approach to scholarship and teaching.
Third, we will discuss the teaching experience in terms of the presences and absences it made apparent.
Improved ferroelectric and endurance properties of Hf0.5Zr0.5O2 thin films by a replacement indium-tin-oxide top electrode process
Authors: Liao Jiajia , Yang Tianyue , Ju Changfan , Yang Qijun , Liao Min , Zeng Binjian , Zhou Yichun
Published: June 2023

The ferroelectricity in HfO2-based thin films offers a potential alternative to non-volatile memories and logic devices. Special top electrodes such as nitride metal serving as a mechanical capping layer are used to induce the ferroelectricity in HfO2, which hinders the extensive application of HfO2 ferroelectrics. Indium-tin-oxide (ITO) is a transparent, highly conductive electrode or semiconductor, widely used in microelectronics. Here, we comprehensively investigated the impact of ITO electrodes on the ferroelectric polarization and endurance properties of Hf0.5Zr0.5O2 (HZO) thin films. The remnant polarization (2P
r) of ∼23.6 μC cm−2 was obtained for the ITO#/HZO/TiN capacitors with an electrode-replacement technique. The relatively enlarged coercive field of ±1.25 MV cm−1 was observed in the ITO/HZO/TiN capacitors compared with TiN/HZO/TiN structures (±0.94 MV cm−1). This might be owing to the work function difference between top ITO and bottom TiN electrodes, as well as the depletion effect of the ITO interface. Furthermore, stable endurance characteristics after 108 cycles were obtained in the ITO#/HZO/TiN capacitors. This work provides a new strategy to obtain excellent ferroelectricity and good reliability in HfO2-based ferroelectric thin film integration with other oxide electrodes.
Numerical simulation of the enhancing effect of micro–nano protrusions on electrostatic fog harvesting
Authors: Zhang Ming , Xiao Menghan , Li Chuan , Li Dingchen , Li Jiawei , Yu Kexun , Pan Yuan
Published: June 2023

Fog harvesting is one potential approach to provide supplementary water resources in arid areas. Considerable research has been devoted to electrostatic fog harvesting technology, but there are still some problems, such as high voltage, complex structures and expensive cost. Decorating micro–nano protrusions on the electrode is an effective method to lower the operating voltage and improve fog harvesting efficiency, and the enhancement effect of protrusions has already been experimentally demonstrated. However, the enhancement mechanism at the microscopic level is less reported. This manuscript tries to explain why micro–nano protrusions can enhance the discharge and electrostatic fog harvesting, via numerical simulation. Three key processes of corona discharge, fog droplet migration and fog harvesting efficiency are discussed in detail, especially the influence of droplet size, the tip radius of the protrusion, the protrusion–protrusion angle and so on. The numerical simulation results show that the inception voltage of the barbed electrode decreases from 7 kV to 3 kV (a decrease of 57%), and the current increases significantly (e.g. by 68% at 15 kV). At 15 kV, the fog harvesting efficiency of the barbed electrode is higher (29.8%) than that of the smooth wire (25.7%), even with a less-effective collection area. The collection efficiency increases with the droplet size, and there is an optimized ratio (∼1‰) of the protrusion tip radius and wire radius to gain high collection efficiency. These research results are beneficial for understanding the microscopic mechanism of protrusions that enhance electrostatic fog harvesting, and provide guidance for further fog harvesting equipment improvement.
Investigation of the dual-frequency bias effect on inductively coupled Cl2 plasmas by hybrid simulation
Authors: Tong Lei , Zhao Ming-Liang , Zhang Yu-Ru , Song Yuan-Hong , Wang You-Nian
Published: June 2023

In the etching process, a bias source is usually applied to the bottom electrode in inductively coupled plasmas (ICPs) to achieve independent control of the ion flux and ion energy. In this work, a hybrid model, which consists of a global model combined bi-directionally with a fluid sheath model, is employed to investigate the dual-frequency (DF) bias effect on the inductively coupled Cl2 plasmas under different pressures. The results indicate that the DC self-bias voltage developed on the biased electrode is approximately a linear function of the phase shift between the fundamental frequency and its second harmonic, and the value only varies slightly with pressure. Therefore, the ion energy on the bottom electrode can be modulated efficiently by the bias voltage waveform, i.e. the fluctuation of the ion energy with phase shift is about 40% for all pressures investigated. Besides, the ion energy and angular distribution functions (IEADFs) in DF biased inductive discharges is complicated, i.e. the IEADFs exhibits a four-peak structure under certain phase shift values. Although the species densities and ion fluxes also evolve with phase shift, the fluctuations are less obvious, especially for Cl2
+ ions at low pressure. In conclusion, the independent control of the ion energy and ion flux are realized in DF biased ICPs, and the results obtained in this work are of significant importance for improving the etching process.
Electronic structures and Aharonov–Bohm effect in higher-order topological Dirac Semimetal nanoribbons with strong confinements
Authors: Du Yan , Tang Shunxi , Tan Han , Liu Zhengfang , Wu Qingping , Zhou Xiaoying , Xiao Xianbo
Published: June 2023

Electronic structures and magnetotransport properties of topological Dirac semimetal (TDSM) nanoribbons are studied by adopting the tight-binding lattice model and the Landauer–Büttiker formula based on the non-equilibrium Green’s function. For concreteness, the TDSM material Cd3As2 grown along the experimentally accessible [110] crystallographic direction is taken as an example. We found that the electronic structures of the TDSM nanoribbon depend on both the strength and direction of the magnetic field (MF). The transversal local charge density (LCD) distribution of the electronic states in the TDSM nanoribbon is moved gradually from the center toward the hinge of each surface as a [010] direction MF strength is increased, forming the two-sided hinge states. However, one-sided surface states are generated in the TDSM nanoribbon when a [001] direction MF is applied. As a result, one-sided hinge states can be achieved once a tilted MF is placed to the TDSM nanoribbon. The underlying physical mechanism of the desired one-sided hinge states is attributed to both the orbital and Zeeman effects of the MF, which is given by analytical analyses. In addition, typical Aharonov–Bohm interference patterns are observed in the charge conductance of the two-terminal TDSM nanoribbon with a tilted MF. This conductance behaviour originates from the unique interfering loop shaped by the one-sided hinge states. These findings may not only further our understanding on the external-field-induced higher-order (HO) topological phases but also provide an alternative method to probe the HO boundary states.
Minimal port-based teleportation
Authors: Strelchuk Sergii , Studziński Michał
Published: June 2023

There are two types of port-based teleportation (PBT) protocols: deterministic—when the state always arrives to the receiver but is imperfectly transmitted and probabilistic—when the state reaches the receiver intact with high probability. We introduce the minimal set of requirements that define a feasible PBT protocol and construct a simple PBT protocol that satisfies these requirements: it teleports an unknown state of a qubit with success probability

p

succ

=
1
−

N
+
2

2

N
+
1

and fidelity

1
−
O
(

1
N

)

with the resource state consisting of N maximally entangled states. This protocol is not reducible from either the deterministic or probabilistic PBT protocol. We define the corresponding efficient superdense coding protocols which transmit more classical bits with fewer maximally entangled states. Furthermore, we introduce rigorous methods for comparing and converting between different PBT protocols.
Potential for Constraining Propagation Parameters of Galactic Cosmic Rays with the High Energy Cosmic-radiation Detection Facility on Board China’s Space Station
Authors: Xu Zhi-Hui , Yuan Qiang , Tang Zhi-Cheng , Bi Xiao-Jun
Published: June 2023

Precise measurements of the spectra of secondary and primary cosmic rays are crucial for understanding the origin and propagation of those energetic particles. The High Energy Cosmic-radiation Detection (HERD) facility on board China’s Space Station, which is expected to operate in 2027, will push the direct and precise measurements of cosmic-ray fluxes up to PeV energies. In this work, we investigate the potential of HERD for studying the propagation of cosmic rays using measurements of boron, carbon, and oxygen spectra. We find that, compared with the current results, the new HERD measurements can improve the accuracy of the propagation parameters by 8%–40%. The constraints on the injection spectra at high energies will also be improved.
Observation of the Semidiurnal Internal Tides in the Northwest Pacific Ocean
Authors: Xie Sihang , Jiang Yifei , Zhou Yong
Published: June 2023

Internal tides are internal waves occurring in the tidal frequency bands of stable stratified oceans, which are formed by the interaction between barotropic tides and different submarine topographical features such as ridges, sills, trough, trench and continental shelf break. In-depth study of tidal energy and tidal dynamics in this area is of great significance for understanding the multi-scale energy cascade structure in this ocean. Based on the 16-day mooring observation data of a set of high spatial and temporal resolution in the Northwest Pacific Ocean from 21°N to 22°N,124°E to 126°E, this paper reveals the amplitude distribution characteristics of the semidiurnal tidal wave in the northwest Pacific Ocean. The results show that the amplitude of the semidiurnal internal tides increases first and then decreases during the change of the depth from small to large. The amplitude is small at the surface and bottom of the ocean, and reaches the maximum at the middle of the ocean, with the maximum value of 40m
Analysis on Causes of the “4·21” Indonesian Submarine “Nanggala” Crash Based on Satellite Images
Authors: Chen J. , Bao S. L. , Wang H. Z. , Jin B. G. , Bai C. Z. , Kong X. J. , Li M. G.
Published: June 2023

In view of the “4·21” Indonesian submarine “Nanggala” crash event, an analysis of the marine environmental factors that may lead to the crash is carried out. The results show that the ocean internal wave is one possible cause of the disappearance of Indonesian submarines. The event is most likely that the submarine was subject to the so called “sea cliff” when encountering large-amplitude ocean internal waves, and at the same time, the officers and soldiers on board failed to take reasonable evasive measures in time, resulting in the submarine losing control and falling below the maximum safe diving depth, making the submarine crack under the pressure of the huge sea, resulting in a submarine accident. This conclusion is obtained based on the analysis of integrated ocean internal wave satellite images and numerical simulations.
The temporal and spatial distribution of sea fog in offshore of China based on FY-4A satellite data
Authors: Kong Xiaojuan , Jiang Zhuhui , Ma Ming , Chen Nan , Chen Jian , Shen Xiaojing , Bai Chengzu
Published: June 2023

Satellite remote sensing is an important instrument of sea fog monitoring. In order to study the temporal and spatial distribution characteristics of sea fog and the influence of sea surface temperature (SST) on the sea fog, based on sea fog monitoring and SST products from FY-4A satellite, the monthly variation of sea fog and monthly average SST in five typical sea areas (including Bohai Sea, Yellow Sea, East China Sea, Taiwan Strait and South China Sea) are statistically analyzed. The results show that the sea fog in offshore has strong regional and seasonal characteristics. From winter to autumn, the sea fog first appears in the Beibu Gulf of the South China Sea, the sea fog extends from South China Sea to East China Sea, and then to Yellow Sea, finally to Bohai Sea. Sea fog is related to sea surface temperature. By comparing the sea fog with the SST distribution, the optimal SST is from 7 °C to 25 °C when the sea fog happens.
Short-term Forecasting of Sea Ice Thickness Based on PredRNN++
Authors: Liu Quanhong , Zhang Ren , Wang Yangjun , Yan Hengqian , Xu Jing , Guo Yutong
Published: June 2023

The navigational potential of the Arctic shipping routes is gradually emerging under the trend of melting Arctic sea ice. However, the opening of the Arctic shipping routes still faces many difficulties, especially the complexity of sea ice changes and the navigational safety risks caused by the uncertainty of the sea ice forecast. In recent years, the deep learning method has emerged in sea ice forecasting due to its powerful non-linear fitting capability. In this paper, from the perspective of combining deep learning methods with expertise in meteorology and oceanography, an improved predictive recurrent neural network (PredRNN++) model is applied to sea ice thickness (SIT) forecasting for the first time. In this study, the short-term forecast (1-3 days) of SIT was realized, and the predictability was tested, confirming the effect of reasonable factor selection and screening on SIT forecasting.
Numerical Study on the Genesis of Incipient Vortex of a Tropical Storm over the South China Sea. Part I Control Simulation
Authors: Liu X , Yin T N , Hao S , Yao Z Y , Zhang Y
Published: June 2023

The previous work has found that strong sensible heating (SH) over the South China Sea (SCS) and western Pacific and related condensation latent heating (LH) are of great significance for the genesis and growth of the initial disturbance of Mindulle (2010). The Weather Research and Forecasting (WRF) model is used to simulate the genesis process of the storm Mindulle using grids nested to high resolution without bogusing. The numerical simulations are executed to determine the impact of the anomalous SH from the SCS on the incipient vortex of the storm formation, including the control-run with and the sensitivity-run without such heating. In the control simulation, the genesis process of the incipient vortex of Mindulle was reproduced along with the reasonable simulated SH over the SCS compared with the observations, which shows that the WRF model has an ability to simulate the formation process of tropical cyclones at the pre-WISHE stage without bogusing over the SCS basin.
Preliminary validation for an eddy-resolving Global Ocean Forecasting System –NMEFC-NEMO
Authors: Zhang Y , Mo H E , Zu Z Q , Qin Y H
Published: June 2023

This paper details the dynamical framework of the National Marine Environmental Forecasting Centre high-resolution global numerical ocean forecasting system (hereinafter referred to as NMEFC-NEMO) and provides a preliminary assessment of its simulation capability in the ocean climatic state. NMEFC-NEMO is developed based on the NEMO version 3.6 and the LIM version 3, and the Local Error Subspace Transform Kalman Filter (LESTKF) ensemble assimilation method is used. The preliminary climatic state assessment shows that the model can reproduce the temperature, salinity and current structure in the observational and reanalysis well, and the results of sea surface temperature and sea surface salinity are 0.05°C and 0.29 PSU colder and saltier, respectively, compared to WOA09. The difference of standard deviation for sea surface height is 0.027 compared to AVISO. We also find that the global mean salinity and kinetic energy of the NMEFC-NEMO are slightly larger in the upper layer relative to the other dataset, which could related to the model parameters setting or insufficient dynamic adjustment.
Three-Dimensional Thermohaline Structure Reconstruction in the Northwest Pacific Ocean from HY-2 Satellite Data Based on a Variational Method
Authors: He Zikang , Wu Xiangyu , Jin Baogang , Chen Zhiqiang , Liu Juan , Wang Zhaoyi
Published: June 2023

In this study, a variational method was used to reconstruct three-dimensional thermohaline fields in the Northwest Pacific Ocean. First, we evaluate the applicability of HY-2 satellite data in three-dimensional thermohaline fields reconstructions, and it confirms that the HY-2 data are reliable. A comparison with the forecast products of operational system shows the reconstructions can describe the structural characteristics of the ocean three-dimensional thermohaline fields and reflect the mesoscale change process of the ocean.
Anthropogenic Influences on the Hydrodynamic and Tidal Discharge in Tongzhou Bay, Nantong, China
Authors: Chen F. , Zhou G. H. , Kong J.
Published: June 2023

In this study, we determined the variations of tidal flow field and tidal prism caused by human activities in Tongzhou bay and using MIKE 21 hydrodynamic model as analyzing tool. After the human activities, the hydrodynamic in sea area alongshore engineering is changed, the most obvious changes can reach over 0.1m/s; the tidal discharge decreases caused by the land accretion leading to the shrink of the area of Nantong near-shore waters, there is up to 12% reduction after planned reclamation during one spring tide period.
A Marine Magnetometer Based on TMR
Authors: Li Z. B. , Du Q. F. , Zhang R. , Luo H. H. , Pan M. C. , Chen D. X. , Zhang Q. , Hu J. F. , Zhang J. S.
Published: June 2023

TMR (tunneling magnetoresistance) has the characteristics of high sensitivity, large linear range, low power consumption, and easy miniaturization, and has received great attention in the field of miniaturized and high-performance magnetic sensors. Widely used in marine magnetic field detection, earthquake monitoring, industrial control, and other fields. In this paper, A TMR marine magnetometer with AC modulation and magnetic field feedback compensation is proposed, designed, and manufactured, which can be used for the measurement of weak marine magnetic fields. After testing, its measurement range is ±100,000nT, the noise fluctuation level is 0.27nT, and nonlinearity level reaches 0.07%. It works by means of ac modulation and real-time compensation of feedback magnetic field, which greatly reduces magnetic hysteresis and increases the linearity. Compared with the nonlinearity of TMR material (more than 20% within ±1Oe, more than 7% within ±0.3Oe), it has been significantly improved.
Analysis of Influence of the Seamount in the South China Sea on Sound Propagation
Authors: Liu Yuyao , Li Lifan , Chen Yu , Chen Wei
Published: June 2023

The influence of seamounts on sound propagation is very important, and it is also a research hotspot for hydroacoustic. This paper uses the BELLHOP ray model to analyze the influence of seamounts in the South China Sea on sound propagation, it is found that the blocking of seamounts has a greater impact on the spatial distribution of the transmission loss. When forward propagation, the distribution of the transmission loss is mainly influenced by seamounts, and its temporal variation is not obvious. When the sound source is relatively far away from the first seamount, the first seamount does not have a great influence on the distribution of the transmission loss. When backward propagation, the transmission loss increases rapidly after passing through the first seamount. Most of the sound energy is blocked due to the higher height of the first seamount. In addition, the impact of the undulating bottom on the front of seamounts on sound propagation should also not be ignored during backward propagation. The seamount determines the most important characteristics of the transmission loss distribution, while the undulating bottom has a certain degree of influence on the distribution characteristics of some specific regions. The above results have important applications for target detection and hydroacoustic communication in the area of seamounts.
Research on magnetic anomaly detection method assisted by geomagnetic map
Authors: Yu Ziqiang , Pan Mengchun , Liu Zhongyan , Xu Yujing , You Guanjie , Zhang Qi
Published: June 2023

Magnetic anomaly detection is a detection technology for underwater/underground ferromagnetic targets. In the geomagnetic anomaly area, the change of magnetic feld is very complicated, and the detection ability of traditional detection methods will decline sharply. To solve this problem, we construct a high-precision local geomagnetic map, which turns geomagnetic anomalies into known prior information to assist detection. Firstly, the accuracy of local geomagnetic map is improved by the optimized variation function of interpolation algorithm and an efficient mapping strategy. Secondly, the magnetic target detector assisted by geomagnetic map is designed on basis of BP neural network and its internal structure is optimized. Finally, simulation and experiment were carried out. The results show that the method improves the detection performance in the geomagnetic anomaly area by 75%–80%, and well-adapted to low SNR situations. This proposed method makes the detection of geomagnetic anomaly are effective.
Vertical array signal recovery method based on normalized virtual time reversal mirror
Authors: Li P , Zhang X G , Zhang X Y , Liu Y
Published: June 2023

Focusing on the vertical array source signal recovery method, aiming at the estimation deviation caused by environment mismatch in the engineering application of virtual time reversal mirror technology, this paper proposes the normalized virtual time reversal technology through theoretical derivation and analyzes the performance of the virtual time reversal technology under the change of environment and signal-to-noise ratio through simulation. Finally, the practicability of the normalized virtual time reversal method and the effectiveness of model correction are verified through experimental data. The data processing results show that the source level estimation error of vertical array based on normalized virtual time reversal algorithm is less than 5.2dB. In the experimental environment of this paper, the correlation of signal spectral structure recovered by this method is about 5% higher than that by the traditional method.
Investigation on low-frequency sound propagation characteristics of fluid-filled steel pipeline
Authors: Song J , Li Q , Shang D
Published: June 2023

With the development of vibration reduction and noise reduction technology, the propeller noise, hydrodynamic noise and equipment base noise in submarines have been effectively suppressed. The sea pipeline system contains mechanical noise and fluid pulsation noise, which is one of the main noise sources of submarines. The fluid-filled steel pipeline is the basic component of the sea pipeline system. It is of great significance to study the low-frequency sound propagation characteristics of the fluid-filled steel pipeline system to effectively suppress the low-frequency noise of the pipeline system to the sea and achieve quiet submarines. At present, there are few studies on the sound propagation of fluid-filled steel pipeline, and most of them refer to gas-filled pipes. It is believed that there are low-frequency plane waves in the pipeline, which leads to the design of muffling devices only for liquids, the role of the pipe wall in the propagation of low-frequency sound is ignored. In this paper, according to the relationship between normal waves and medium wave velocity, a sound propagation model of fluid-filled steel pipeline is proposed, which is verified by experimental research. Through this model, the propagation path of low-frequency sound in the fluid-filled steel pipeline is clarified, which has an important guiding role in the vibration and noise reduction of the fluid-filled pipeline system.
Successive Interference Cancellation for Orthogonal Chirp Division Multiplexing
Authors: Liu Haoyang , He Chuanlin , Bai Yiqi , Liang Zhanyuan , Yin Jiawei , Sun Zhaocheng
Published: June 2023

In this paper, we propose a communication receivers’ architecture to simplify the Orthogonal Chirp Division Multiplexing (OCDM) channel equalization and to subtract multi-carrier interference followed by a successive interference cancellation (SIC) scheme in order to cancel the remaining interference. The interference introduced by underwater acoustic channel is estimated using a pre-acknowledged pilot symbol sequence, and then the interference can be optimally estimated and subtracted from the received signal. This process is repeated simultaneously for all OCDM carriers until a stationary point or a threshold is reached. Simulation results from Watermark are applied to illustrate the performance of the OCDM scheme with the presented successive interference cancellation algorithm. Results shows that the Bit Error Rate (BER) enhancement can reaches 102 in BCH1 channel. As expected, the combination of OCDM and presented SIC algorithm is shown to increase the output SNR over OCDM alone in multi-path shall water acoustic channel.
Effects of non-ideal seabed topography on low frequency sound propagation in shallow sea
Authors: Chai Z G , Wang Q L , Zhu H H , Cui Z Q , Tu H W
Published: June 2023

In order to study the influence of seabed topography on sound propagation under non-ideal conditions, a simulation model of low frequency sound propagation of whole waveguide is established by using finite element method (FEM). The action mechanism of the topography with seamounts on the components of the seismic wave field is studied in time domain. The simulation results show that the propagation of various seismic wave components can be seen intuitively from the time domain. Scholte waves can be excited easily in a suitable range from the seabed, and can propagate along the seabed for a long distance with small attenuation and strong stability. The presence of a seamount allows Scholte waves to scatter, and Scholte waves can travel along the surface of the seamount to the back of the seamount. The path and energy intensity of sound wave change with the change of terrain.
Directivity Research of Sensing Channels in a Distributed Fiber Optic Hydrophone
Authors: Li Wenmin , Lu Yang , Chen Yu , Liang Yan , Meng Zhou
Published: June 2023

An acoustic orientation method using the directivity of sensing channels in distributed fiber optic hydrophone (DFOH) is presented and demonstrated. Theoretical analysis shows that the sensing channel of DFOH is directional. Based on the directivity function of the channel, the direction of the acoustic signal can be obtained by scanning the length of the sensing channel, which is confirmed by experiments.
A Track-before-Detect Strategy for Multi-sensor Passive Acoustic Localization
Authors: Wang Yan , Li Xiang , Qi Bin , Li Shuo , Gao Yongshuai
Published: June 2023

This paper focuses on the multi-sensor passive acoustic localization problem. The traditional solution for the problem is to estimate the parameter of the received signal, such as the time difference of arrival (TDOA). Then the position of the target is solved by the estimated parameter. This solution is suboptimal because estimations are carried out at each sensor separately, and the fact that the received signals of different sensors originate from the same target is ignored. In this paper, we propose a track-before-detect (TBD) method. The proposed method adopts a particle filter that defines its likelihood function as the product of the output of the cross-correlation (CC) between the signal of different sensors conditioned on the particle’s state. This likelihood function is designed to ensure that the processing gain of multi-sensors can be fully obtained. Moreover, the proposed method circumvents the challenging measurement-to-track association problem faced by the method based on the estimated parameter.
A Low-cost Inertial Rail Track Positioning Technology Based on Distributed Optical System Assistance
Authors: Ge Mingming , Chen Xiyuan , Jiang Xuyang , Zhou Yunchuan
Published: June 2023

The low-cost MEMS inertial system is difficult to achieve high-precision measurement for path track, which decreases accuracy of output. Aiming at this problem, a distributed optical track assisted the low-cost inertial system scheme is proposed in this paper. Firstly, the positional relationship of the sub-modules is pre-calibrated on the test track. Secondly, the position and speed are calculated by processing the time difference of the photoelectric interruption. In this system, the low-cost MEMS inertial system is used to measure the attitude, speed, and position information. Subsequently, the data of the inertial system and the optical system are fused by the extended Kalman filter algorithm. To verify the feasibility of the scheme, a short rail speed measurement experimental platform is built in an indoor environment. Compared with the low-cost gyroscope, the result shows that the error divergence assisted by the optical system can be effectively suppressed. The positioning accuracy can reach the centimeter level in the results of the experiment.
A Method for Preparing Superparamagnetic Nanomaterial
Authors: Zhu Xiaobing , Zhang Yi , Ye Jian , Wang Lei
Published: June 2023

Substances with superparamagnetism, a special magnetic effect, are magnetized under external magnetic field. When the applied magnetic field disappears, superparamagnetic substances have almost zero magnetization intensity, with quite small coercivity. The performance of magnetic powder or magnetic suspension used in magnetic particle detection greatly affects detection sensitivity. This paper studies a new method for preparing nano-superparamagnetic non-destructive testing materials by combing membrane technology and chemical co-precipitation method. Magnetic nano-ferroferric oxide particles were prepared by preparing membrane reactor based on chemical co-precipitation method to find the optimal synthesis conditions for nano-ferroferric oxide particles. Polymer nano-magnetic materials with good dispersibility, superparamagnetism, high dispersibility, uniform particle size distribution were obtained, which can well detect cracks, especially small cracks. It is a good magnetic nondestructive testing material.
A Learning Sentiment Database for Machine Learning
Authors: Zhang Jing , Hu Siquan , Shi Zhiguo , Han Shumin
Published: June 2023

Learners’ affective states play a crucial role in learning evaluation, and the external expressions that can directly reflect affect are facial expressions. However, the sample size of the database for the learning process of learners is limited, and most of the existing expression databases are the expressions of ordinary people, which is difficult to support an in-depth study of the emotional states of learners in learning scenarios. In order to better study the influence of learners’ emotion on the learning state, we built a learning expression database for machine learning, and at the same time labeled the data with expression-emotion state, and finally formed a database of 8,000 expression images containing 36 learners, which is important for studying learners’ emotion state under learning scenarios.
A tensile property measuring system for miniaturized samples from 300 K to 70 K based on pulse tube cryocooler
Authors: Qi H.Y. , Shen F.Z. , Zhang H.C. , Huang C.J. , Han Y.M. , Zhao Y.C. , Xin J.J. , Geng Z. , Wang W. , Li L.F. , Zhou Y.
Published: June 2023

With the rapid development and wide application of cryogenic, superconducting and space technologies in engineering fields, measurements of the mechanical properties especially the tensile properties of small-sized samples at cryogenic temperatures are more and more important. In this study, a tensile property measuring system for miniaturized samples was designed and built, where the samples can be measured from 300 K to 70 K with a resolution of 0.1 K. The cryogenic environment was provided by a pulse tube cryocooler. The force load applied to the sample was up to 10 N with a resolution of 0.001 N. The structure of the cryogenic system and sample holders were specially designed for miniaturized samples. A control and automatic data acquisition system was used to control and acquire data from all devices of the instrument. The simulations of the stretching part under load at cryogenic temperature were performed to ensure the measurement accuracy and reliability. To verify the performance and accuracy of the system, the tensile properties of two kinds of fine high-purity copper wires were measured at both 77 K and 300 K. The tensile measurement results were discussed and the measurement uncertainty of the system was analyzed. With different clamps more kinds of mechanical measurements of miniaturized samples can be carried out on this system.
Liquefaction Mitigation of Ramp On Kretek 2 Bridge
Authors: Galag C T S A , Faris F , Adi A D
Published: June 2023

The Kretek 2 Bridge was built over the Opak River where there is an active fault. According to bore log data and embankment site analysis, there is potential for liquefaction at a depth of 0 - 3 meters. Due to space limitations, ramp of bridge must be able to stand upright. An alternative treatment that can be implemented in this condition is to reinforce the embankment at the bridge ramp with the Mechanically Stabilized Earth Wall system. Analysis of liquefaction potential using the method of Idriss and Boulanger. Analysis of the application of the planned MSE wall was carried out based on the external, internal, and global stability in dynamic conditions in the subgrade after replacing the subgrade in the detected layer of liquefaction potential. The method for calculating the lateral pressure caused by an earthquake uses the pseudostatic method. The MSE wall with soil replacement meets the requirements for external, internal, and global stability under dynamic conditions to be an alternative solution to mitigate liquefaction potential and increase soil bearing capacity and limitation area problems. Reinforcement of friction tie using granular embankment gets good results in the calculation of safety factor breaking, pull out, overturning, and sliding.
Axial and lateral bearing capacity assessment of bored piles on medium-dense sand and liquefiable potential based on numerical simulation
Authors: Zakariya A , Rifa’i A , Ismanti S , Hidayat M. S.
Published: June 2023

Liquefaction on bridges can cause structural failure due to loss of soil strength. The Showa Bridge that collapsed in 1964 Niigata earthquake was caused by buckling in piles as the soil layer liquefied and friction losses. In addition, there was a case of Palu IV bridge collapse in Indonesia during the recent 2018 Palu earthquake, which indicated have been affected by earthquakes and liquefaction. This study examines the reliability of the bored pile foundation of the Kretek 2 Bridge in Bantul Regency, Yogyakarta Special Region Province, for axial and lateral bearing capacity. This research method uses the soil structure interaction and 3D numerical simulation by Midas Civil and Midas GTS NX pile modeling. The pile driving analysis and lateral static loading test were also conducted, which can be compared to MIDAS results. For the foundation modeling result, there is an increase in axial and moment forces but a decrease in shear forces during liquefaction. While the lateral displacement increases significantly in the liquefaction state, foundation performance is still stable. Therefore, the foundation of the kretek 2 bridge is sufficient to support axial and lateral load both in a static state and a liquefaction state.
The Effect of High Pore Water Pressure on Liquefaction Potential in Sidoarjo Mud Volcanoes (LUSI)
Authors: Wijanarko D , Adi A D , Rifa’i A
Published: June 2023

LUSI until now is still active and holds the potential for subsequent disasters due to the influence of high pore water pressure in the affected area. The presence of high pore water pressure will cause a decrease in effective stress and decrease in soil / rock strength. This type of subsequent disaster is closely related to the process of liquefaction which has the potential to occur with the addition of earthquake events. Analysis of liquefaction potential with empirical analysis on standard penetration test (SPT) based evaluation, with input of soil properties parameters, seismicity, and groundwater level parameters. The groundwater level parameter in the calculation will show a normal pore water pressure value in accordance with the depth of the water-saturated layer. Input of high pore water pressure parameters so far has not been done. CPT-u measurement data for pore pressure value input consists of 13 points of measurements was on the northern embankment, with the lowest level of stability. The input of these parameters will provide variations in the differences in the level of potential liquefaction in the study area. The result is changes occur in the decrease in the safety factor value ranging from 0.1-0.4 and the change in the liquefaction potential index (LPI) value from originally low to high, and originally high to very high. The anomaly input of pore pressure in CPT-u measurement results ranges from 40%-70% higher than normal pore pressure in the sand layer. Analysis of the potential for liquefaction in the study area showed that the results of the high-very high liquefaction potential in the northern and eastern research areas, and the low Liquefaction potential was in the southern and western areas.
The Potential of Bentonite and Chitosan Mixtures as Clay Liner Base Material
Authors: Hidayat T , Arifin Y F
Published: June 2023

A polymer-enhanced bentonite-sand mixture has been widely used as a clay liner. This research focuses on the potential use of chitosan as a natural polymer mixed with bentonite as a clay liner base material. The bentonite used is a type of calcium bentonite, which is easily obtained in the market. Meanwhile, chitosan is produced from shrimp shell waste and is also easily available in the market. The process of mixing chitosan with a percentage of 2–6% of bentonite was carried out using a certain method, which is described in detail in the article. The materials’ physical, chemical, and engineering characteristics, such as Atterberg limits, permeability, and compressive strength, were examined after mixing. The results show that the mixing process was successful for the finding of minerals and functional groups based on the XRD and FTIR results. Promising results of the study include larger clusters, higher plasticity, decreased permeability, and higher compressive strengths of the mixtures after chitosan was added to bentonite.