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Unmanned aerial vehicles (UAVs) deployed as a swarm can offer a flexible and cost-efficient solution for surveillance missions in large-scale adversarial environments. UAV swarms possess superior real-time surveillance capabilities in detecting time-sensitive targets with speed and security, surpassing alternative techniques such as satellites and ground-based sensors. However, the area surveillance problem in adversarial scenarios using UAV swarms necessitates careful consideration of factors such as swarm positioning, flight attitudes, antenna directionality, the threat posed by adversary detection systems (ADSs), and swarm network topology. To address this challenge, we propose the Integrated Low Detection Probability (ILDP) deployment method for UAV swarms, which incorporates the Danger Avoidance Distributed Motion control algorithm (DADM) for swarm collaboration and the Low Detection Probability Topology Control algorithm (LDPTC) for swarm networking. The DADM algorithm facilitates swarm cooperation in achieving area coverage and evading ADSs by leveraging neighboring, environmental, and threat information in adversarial scenarios. Furthermore, the LDPTC algorithm establishes a topology optimization model that comprehensively considers swarm distribution and the impact of directional antenna sidelobes to reduce transmitting energy leakage on the ground. Our strategy significantly decreases the detection probability of UAV swarms by ADSs, ensuring the operational effectiveness of UAV swarms in dynamic adversarial scenarios. Extensive simulations validate the superiority of our proposed ILDP method, demonstrating considerably lower detection probabilities compared to other approaches in static and dynamic adversary environments across various swarm scales. Moreover, our method excels in real-time surveillance capabilities with lower computational complexity, freeing up computing resources for UAVs to fulfill additional tasks.

The current research primarily focuses on the impact of full-ring expansion on tunnel safety, but the relationship between local expansion of the surrounding rock and initial water content is rarely studied yet. Therefore, this paper analyzes the mechanics and deformation characteristics of a tunnel passing through an expansive mudstone area in a tunnel project in China. The analysis considers different local expansion areas and the initial water content of the surrounding rock. The research findings indicate that the local expansion of the tunnel’s vault and sidewall has the most significant impact on the deformation range of the surrounding rock. Compared to other expansion conditions, the deformation difference can reach a maximum of 156 mm. The order of expansion conditions leading to the development of plastic zone volume in the surrounding rock is as follows: full-ring expansion > vault expansion > local vault expansion > sidewall expansion > invert expansion. When the initial water content reaches a certain level, the expansion effect becomes less significant due to the upper limit of the surrounding rock’s expansion capacity. However, an increase in water content will cause the surrounding rock to soften and intensify the expansion of the deformation range. The local expansion of the surrounding rock not only increases the bending moments on the preliminary lining at the section directly affected by the expansive force but also significantly impacts other expansion areas. The local expansion of the vault and sidewall greatly influences the stability of the secondary lining, resulting in some areas having a safety factor lower than the allowed value. However, from the perspective of overall tunnel safety, the secondary lining still provides a certain safety margin.

Underwater sound absorption materials with a stable performance at various hydrostatic pressures are important for marine applications. However, most studies about underwater sound absorption materials only focused on the performance at atmospheric hydrostatic pressure, while ignoring the influence of various hydrostatic pressures. Aiming to improve the underwater sound absorption stability of a metamaterial at various hydrostatic pressures, different structures and a Nelder–Mead algorithm with an acoustic-structure fully coupled finite element method (FEM) model are developed to optimize the structure of the metamaterial at various hydrostatic pressures. In this numerical modeling, the metamaterial is a PDMS matrix embedded with periodic cylinders. Firstly, the effect of hydrostatic pressure on the metamaterial is evaluated in the frequency range [0, 8 kHz]. Secondly, different cases are designed to improve the underwater sound absorption stability at various hydrostatic pressures, including different cylinder radii, different distances between the air cylinder and the steel backing, and different void shapes. Then two layers of air and/or steel cylinders are introduced to further improve sound absorption performance under various hydrostatic pressures. The results indicate that PDMS with two layers of air cylinders have the optimal sound absorption stability performance under various hydrostatic pressures, which can be attributed to the top layer of air cylinders absorbing the main deformation. Lastly, the optimization algorithm significantly improves the sound absorption performance of the metamaterials at various hydrostatic pressures. This combination of an optimistic algorithm and FEM can guide the design of underwater sound absorption metamaterials at various hydrostatic pressures.

Marine fouling can cause a series of hazards in the marine industrial field, and the traditional antifouling methods do not fulfill the green antifouling requirement. Herein, a novel DA/PEI/SiO2/antibacterial peptide antifouling coating was prepared by a multi-modification approach. Initially, the nanocoatings were prepared by depositing DA, PEI, and SiO2on the dopamine (DA)-modified 304 stainless steel (SS) surface, and finally, the DA/PEI/SiO2/AMPs composite coatings were prepared by grafting antimicrobial peptides (AMPs). The surfaces of SS before and after modification were characterized by Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectrometer (XPS), field emission scanning electron microscopy (SEM), contact angle measurement, and 3D optical profilometer. SSN-1 cells were used to evaluate the cytocompatibility of the modified surface. The results revealed that the cells cultured on the modified surface still maintained a good adhesion morphology, demonstrating the superior cytocompatibility of the composite coating. The anti-biofilm and antimicrobial properties of the modified samples were evaluated using Vibrio natriegens. The antibacterial efficiency of SS-DA/PEI/SiO2surfaces before and after AMPs modification reached 78.39 and 95.90%, and anti-biofilm efficiency of AMPs modified surface achieved 72.87% corresponding to 44.19% of SS-DA/PEI/SiO2. The successful grafting of AMPs improved the antibacterial and anti-biofilm properties of the modified sample surfaces. Electrochemical and stability tests indicated that the modified sample surfaces exhibited excellent corrosion resistance and antifouling stability properties. This research could provide a novel green anti-fouling and anti-corrosion strategy for the marine industry and other related fields.

With the development of artificial intelligence technology in various fields, the traditional accounting method is no longer applicable to the personalized development of e-commerce industry; Therefore, it is essential to improve the accounting method and construct a personalized recommendation model for e-commerce. Based on this background, this study firstly reconstructs the steps of accounting element recognition in the traditional accounting system and constructs an automated accounting recognition mechanism using BP neural network algorithm, aiming to improve the accuracy and efficiency of accounting element recognition; Secondly, a personalized e-commerce recommendation model based on multiple intelligence is built, which uses intelligent Q-learning algorithm to optimize the recommendation module, aiming to improve the accuracy of personalized recommendation. By comparing the performance of different accounting models under different personalized e-commerce systems, the accounting model proposed in this paper can predict the accounting entries well under the three-layer BP neural network, and the error between the maximum predicted value and the actual value is 0.23%. The recommendation model proposed in the study outperforms the traditional recommendation model and the recommendation model under collaborative filtering algorithm in predicting customers' personal preferences, whose predicted value is closer to the real situation. In summary, both the accounting method and the personalized recommendation model for e-commerce proposed in this study can achieve better application results, thus providing a new idea for the development of the e-commerce industry.

Differences of cyanide leaching between the calcine and the dust from a refractory gold concentrate were investigated by comparative method. Results showed that gold leaching efficiencies of the calcine and the dust were 85.31% and 54.30%, respectively, with direct cyanidation. Contents and existing forms of arsenic and carbon were the main reasons for those differences. The maximum gold leaching efficiencies of the calcine and the dust were 87.70% and 58.60%, respectively, with cyanidation after NaOH pre-leaching. Harmful elements removal, gold loss in NaOH pre-leaching and iron oxides hindrance codetermined gold leaching efficiencies of the calcine and the dust. After H2SO4pre-leaching, the maximum gold leaching efficiencies of the calcine and the dust achieved 94.96% and 80.40%, respectively. The effect of carbonaceous matter was the main reason for differences for leaching efficiencies of the calcine and the dust. Based on those differences, two proper gold extraction processes were put forward, and gold leaching efficiencies for the calcine and the dust achieved 94.91% and 91.90%, respectively.

A reagent combination of sodium oleate (NaOl) and salicyl hydroximic acid was employed as the roughing and scavenging collectors, whereas styryl phosphoric acid (SPA) and octanol were employed as the cleaning collectors. Results of bench-scale flotation demonstrate that the dosage of SPA can be reduced by about 80%, and that a better flotation index can be obtained using the proposed reagent system. The results of adsorption amount and contact angle measurements indicate that the rutile surface adsorbed not only a large amount of residual NaOl but also SPA and a small amount of NaOl remained on the amphibole surface in strong acidic solution. The hydrophobic difference between rutile and amphibole surfaces was therefore amplified in cleaning, and their further separation became much easier consequently.

ABSTRACTStyryl phosphoric acid (SPA) is considered to be one of the best selective collectors for rutile flotation. Yet high consumption and considerable environmental pressure have limited its wide applications. In this study, n-nonyl alcohol (NNA) was used as the auxiliary collector to reduce SPA dosage. The experimental results indicated that when SPA was used as the single collector, the rutile flotation presented an optimum index of recovery being 52.26% and the grade being about 45% with a SPA concentration of 0.4 × 10−4 mol L−1. But when 0.4 × 10−4 mol L−1SPA and 0.4 × 10−4 mol L−1NNA were used as the mixture collectors, the resulting recovery increases to 82%, and the grade reached 47%. The synergistic adsorption mechanism was investigated by foam properties measurements, zeta potential measurements and FT-IR analysis. NNA increased the foam amount and improved its stability, and quickly reduced the surface tension of the solutions. On the other hand, SPA was first adsorbed on the rutile surface, and then NNA chemically reacted with SPA in the form of hydrogen bond.

A soft landing directly influences the safety of devices and the follow-on work of a lander. Therefore, research on the interaction between the lander and the lunar regolith is of great significance. Different from the regular test experiments and finite element simulation, the landing impact is studied in a manner that combines a theoretical method and a discrete element simulation based on EDEM, which is more suitable for the simulation of the discrete particles due to the discontinuous properties of lunar regolith. Based on the properties of the lunar regolith and discrete element theory, this paper establishes the theoretical model and the discrete element model of the interaction between the lander and the lunar regolith. The influence of the lander structure and the lunar terrain on this interaction is analyzed through contrastive analysis of different work conditions.

The adsorption behavior and mechanism of Bi(III) ions on the rutile–water interface were investigated through micro-flotation, Zeta potential measurement, adsorption amount measurement and X-ray photoelectron spectroscopy (XPS). According to the results of micro-flotation, Bi(III) ions could largely improve the rutile flotation recovery (from 62% to 91%), and they could increase the activating sites and reduce the competitive adsorption between nonyl hydroxamic acid negative ions and OH−ions, which determined that Bi(III) ions were capable of activating rutile flotation. The adsorption of Bi(III) ions onto the rutile surface led to the shift of Zeta potential into the positive direction, which was good for the adsorption of nonyl hydroxamic acid anions. In addition, the results of XPS indicated that the chemical environment around Ti atom had not changed before and after the adsorption of Bi(III) ions. Based on the adsorption mechanism of Bi(III) ions, it was deduced that firstly Bi(III) ions occupied the vacancies of the original Ca2+, Mg2+and Fe2+ions on the rutile surface; secondly Bi(III) ions covered on the rutile surface in the form of hydroxides.

Acute liver failure (ALF) is an unpredictable and life-threatening critical illness. The pathological characteristic of ALF is massive necrosis of hepatocytes and lots of inflammatory cells infiltration which may lead to multiple organ failure.

Customer Relationship Management (CRM) is becoming the focus of enterprise and an active research field of computer science. The ariticle introduces some basic concepts about CRM and data mining, and some benefits brought by data mining in CRM. At the end it points out how to apply data mining applications in CRM.

In this paper, we propose a novel and flexible 16-quadrature amplitude modulation (16QAM) transmitter based on cascaded dual-parallel Mach-Zehnder modulator (DPMZM) and phase modulator (PM). The proposed transmitter is able to generate three types of 16QAM signals: square 16QAM, star 16QAM and four-amplitude-four-phase-16-QAM (FAFP-16QAM). The feasibility of the transmitter is verified through experiment, 20-Gb/s eye diagrams of the 16QAM signals are obtained. In order to evaluate the performances of the 16QAM signals, simulations are also conducted using VPI Transmission Maker, clear constellations of 40-Gb/s 16QAM signals are achieved by coherent detection.

We propose and experimentally demonstrate a WDM-PON architecture supporting point-to-point, broadcast, and multicast services based on hybrid modulation format. Wireless access for multicast data is provided using optical carrier suppression (OCS) technology.

We propose and experimentally demonstrate a simple and cost-effective bi-directional RoF system for simultaneous transmission of downstream baseband, MW and MMW signals based on a single-drive Mach-Zehnder modulator (MZM). Upstream data transmission is realized by re-modulation of downstream signals.

We propose and experimentally demonstrate a reconfigurable all-optical VPN scheme enabling intercommunications among different ONUs in a WDM PON. Reconfiguration is realized by dynamically setting wavelength conversion of optical VPN signal using a SOA in the OLT.

Acid leaching wastewater, produced in the acid pre-leaching process of gold-bearing dust, contains a lot of iron (Fe) and arsenic (As). If these wastewater are discharged directly without proper treatment, massive destruction on the environment will be caused, and a large amount of arsenic and iron resources will be wasted. In this study, Fe(III) reduction by pyrite, recovery and purification of crude green-vitriol and crude As2O3, and disposal of arsenic-bearing solid waste were studied. Based on those studies, a novel process containing Fe(III) reduction with pyrite, iron recovery after Fe(III) reduction, and arsenic recovery from the solution after iron recovery was proposed to separate and recover Fe and As from an acid leaching wastewater. Results showed that reduction efficiency of Fe(III) in acid leaching wastewater achieved 96.43% under the optimal conditions (80 °C, L S−15:1, 3 h). Recovery efficiency of iron in crude green-vitriol achieved 82.37%; moreover, 73.32% As remained in the solution after iron recovery. Through purification, purified green-vitriol reached the national standard of class-I green-vitriol (GB 10531-2006), and the direct recovery efficiency of iron was 51.46%. Through neutralization, SO2reduction, recovery and purification of crude As2O3, purified As2O3reached the national standard of As2O3-3 (GB 26721-2011), and the direct recovery efficiency of arsenic achieved 74.89%. This process realized the efficient recovery of iron and arsenic from acid leaching wastewater, and also realized the harmless disposal of arsenic-containing solid waste.