Search

The oxygen discharge process significantly affects the electrochemical performance of a proton exchange membrane water electrolyzer (PEMWE), which requires an optimal structure of the flow field implemented in the bipolar plate (BP) component. In this study, we numerically investigated the two-phase (liquid water and oxygen) flow in the PEMWE's channel region with different outlet manifold structures utilizing the volume of fluid (VOF) model. Then, the oxygen volume fraction at the liquid/gas diffusion layer (L/GDL) surface, i.e., the interface of the channel and L/GDL, obtained by the liquid water and oxygen flow model was incorporated into a three-dimensional (3D) PEMWE model, which made it possible to predict the influence of the outlet manifold structure on the multiple transfers inside the whole electrolyzer as well as the electrochemical performance. The results indicate that the existence of oxygen in the flow field significantly decreased the electrolyzer voltage at a fixed operation current density and deteriorated the uniform distribution of the oxygen amount, current density (corresponding to the electrochemical reaction rate) and temperature in the membrane electrode assembly (MEA), indicating that the rapid oxygen removal from the flow field is preferred in the operation of the electrolyzer. Moreover, slight increases in the width of the outlet manifold were helpful in relieving the oxygen accumulation in the anode CL and, hence, improved the electrolyzer performance with more uniform distribution characteristics. [ABSTRACT FROM AUTHOR]

Nowadays, more and more brands use interesting anime characters to promote and increase brand awareness. However, real-time and interesting promotional materials are also one of the key factors to attract people, so real-time processing of anime characters has also become an effective way to enhance brand awareness. In recent years, with the rapid development of deep learning, image style conversion based on AI technology has become a much-attended artificial intelligence application, but it also suffers from the disadvantages of complex model structure, slow conversion speed, and inconspicuous identity features, which need to be improved. In view of this, this study proposes an anime portrait realization (ARF-GAN) algorithm based on generative adversarial network. This algorithm is based on the Pix2Pix architecture and also uses the U-net network structure with jump connections to connect the encoder’s feature maps directly to the decoder, which in turn enables the network to reconstruct the output data in a better way and the network architecture is more lightweight.This algorithm is based on the Pix2Pix architecture and also uses the U-net network structure with jump connections to connect the encoder’s feature maps directly to the decoder, which in turn enables the network to reconstruct the output data in a better way and the network architecture is more lightweight. It also introduces the CBAM module, which can enhance the model’s expressive and generative capabilities without increasing the model’s complexity, and improve the model’s real-time image processing capability. In addition, this paper also compensates for the problem of image blurring brought by the original architecture by introducing the deblurring module. The experimental results on CartoonFaceAB, DanBooru show that the proposed ARF-GAN has a better generative effect for the task of realizing anime portraits. And comparing with different types of image generating models, it shows better accuracy and lower complexity by using several evaluation indexes such as PSNR and SSIM. This makes it more suitable for brand advertisement promotion, so it has good application value for improving brand awareness. [ABSTRACT FROM AUTHOR]

A series of CaF2-Al2O3-TiO2 welding fluxes with TiO2 content from 20 to 60 wt.% were applied to join EH36 shipbuilding steel under high heat input submerged arc welding. The effect of TiO2 content on Charpy impact energy, inclusion characteristics, microstructure features, and chemical compositions of weld metals were systematically investigated. A maximum Charpy impact energy of 81.67 J was detected for the weld metal treated by the flux with 50 wt.% TiO2. Such unusual behavior was consistent with the initially increased and subsequently decreased changing trend for the faction of acicular ferrite, which is closely related to the formation, number density, and size distribution of significantly populated TiO2-containing inclusions that were largely dictated by the transfer of O and Ti. Current findings may serve as a viable way of tuning weld metal properties enabled by optimized flux designs. [ABSTRACT FROM AUTHOR]

As nonlinear thermal devices, thermal regulators can intelligently respond to temperature and control heat flow through changes in heat transfer capacities, which allows them to reduce energy consumption without external intervention. However, current thermal regulators generally based on high‐quality crystalline‐structure transitions are intrinsically rigid, which may cause structural damage and functional failure under mechanical strain; moreover, they are difficult to integrate into emerging soft electronic platforms. In this study, we develop a flexible, elastic thermal regulator based on the reversible thermally induced deformation of a liquid crystal elastomer/liquid metal (LCE/LM) composite foam. By adjusting the crosslinking densities, the LCE foam exhibits a high actuation strain of 121% with flexibility below the nematic–isotropic phase transition temperature (TNI) and hyperelasticity above TNI. The incorporation of LM results in a high thermal resistance switching ratio of 3.8 over a wide working temperature window of 60°C with good cycling stability. This feature originates from the synergistic effect of fragmentation and recombination of the internal LM network and lengthening and shortening of the bond line thickness. Furthermore, we fabricate a "grid window" utilizing photic‐thermal integrated thermal control, achieving a superior heat supply of 13.7°C at a light intensity of 180 mW/cm2 and a thermal protection of 43.4°C at 1200 mW/cm2. The proposed method meets the mechanical softness requirements of thermal regulator materials with multimode intelligent temperature control. [ABSTRACT FROM AUTHOR]

At extreme deep-sea pressure, the assessment of the electroacoustic conversion performance of transducers is a major problem, particularly in the acoustic exploration of seabed sediment in 11,000-m abysses. To address this problem, an online measurement method was proposed for the electroacoustic performance under extreme pressure. The method utilized the 11,000-m transceiver with the high-frequency and narrow-beam characteristics. In the full-depth pressure profile, the transceiver signal was measured online by an extreme pressure simulation device. At different extreme pressure sites, characteristics of the transceiver signal were analyzed using the transceiver signal at atmospheric pressure as the reference. The characteristics included amplitude response characteristics, frequency response characteristics and time-frequency characteristics. The 11,000-m transceiver has verified the stability and reliability of its electro-acoustic conversion performance. It was also analysed the effect of the transducer on the calculation of seabed sediment parameters in a pressure environment. [ABSTRACT FROM AUTHOR]

Capacitive deionization is an electrochemical ion removal technique that has broad application prospects for the efficient desalination of brackish water. The current research mainly focuses on the improvement of the electrode material performance and device structure for capacitive deionization. However, the capacitive deionization process is subject to the coupling effect of multiple physical parameters inside the porous electrode, the dominant order and optimization of multiple physical parameters in the capacitive deionization process are needed to be further investigated. In this study, the ion transport in porous electrode of the capacitive deionization is investigated via numerical simulation and physical similarity analysis. Fourteen dimensional physical parameters involved in ion transport are unified into eight dimensionless parameters based on the nondimensionalization of Navier–Stokes and Poisson–Nernst–Planck equations, and the dimensionless parameters are summarized into four categories, including ion adsorption capability, ion transport characteristics, ion motion driving force, and ion adsorption equilibrium time. Analysis based on the numerical models with an irregular porous electrode structure shows that the dimensionless parameters can explain a series of similar physical phenomena in the capacitive deionization processes. Moreover, a parametric sensibility analysis is performed to reveal that the concentration and velocity of inlet solution are dominant factors for optimizing the salt adsorption capacity per unit area and the average salt removal rate. In addition, the inlet solution concentration and electrode potential are critical factors for improving the removal efficiency. The physical similarity and parametric sensitivity analysis in this study provide theoretical guidance for performance improvement in the practical application of capacitive deionization. [ABSTRACT FROM AUTHOR]

We developed a high-frequency submersible sub-bottom profiler (HF-SSBP) instrument for taking deep-sea sediment measurement. In order to evaluate the reliability of profile data, a laboratory calibration method (LCM) was developed using illuminated acrylic standard boards in anechoic tank to form multi-layer reflections and evaluate the errors of the HF-SSBP. Two layer reflections induced by single boards in different thicknesses and ranges were performed and recorded, after which four layer reflections induced by two boards with an adjusted water crack were set and logged. The results showed that the HF-SSBP resolution was 44.9 mm in acrylic and its equivalent in the sediment was 28.5 mm. The absolute measure error was 7 mm with an acrylic board thickness of 100 mm, and the maximum measure error was 3.5 mm in different water thicknesses. As a test and application, deep-sea sediment measurement of the HF-SSBP was launched and compared with in situ sampling cores in the same site. The measurement thickness for sections A and B are 39.4 cm and 23.2 cm, respectively, corresponding to the sampling core of 39.8 cm and 23.7 cm. The two results are close as we expected. This work demonstrates the reliability and accuracy of the HF-SSBP measurement, thus providing a good choice for deep-sea submergence vehicles to carry this sonar instrument to obtain high-resolution stratum in deep-sea surficial sediments. [ABSTRACT FROM AUTHOR]

Microstructural evolution roadmap in the weld metal of EH420 shipbuilding steel subjected to various reheating inputs has been investigated. As reheating inputs increase, major microstructures transform from lath bainites, to granular bainites, to acicular ferrite, and to polygonal ferrite. Corresponding frequencies of high-angle grain boundaries increase from 30 to 57.7 pct as reheating inputs increase from 50 to 150 kJ/cm, while a changeover occurs, leading to an appreciable reduction to 45.5 pct, at 200 kJ/cm. [ABSTRACT FROM AUTHOR]

Next‐generation ultrahigh power density proton exchange membrane fuel cells rely not only on high‐performance membrane electrode assembly (MEA) but also on an optimal cell structure. To this end, this work comprehensively investigates the cell performance under various structures, and it is revealed that there is unexploited performance improvement in structure design because its positive effect enhancing gas supply is often inhibited by worse proton/electron conduction. Utilizing fine channel/rib or the porous flow field is feasible to eliminate the gas diffusion layer (GDL) and hence increase the power density significantly due to the decrease of cell thickness and gas/electron transfer resistances. The cell structure combining fine channel/rib, GDL elimination and double‐cell structure is believed to increase the power density from 4.4 to 6.52 kW L−1 with the existing MEA, showing nearly equal importance with the new MEA development in achieving the target of 9.0 kW L−1. [ABSTRACT FROM AUTHOR]

In the study of sedimentary acoustics, measuring sound speed in the first layer sediment is a key issue. To solve this problem, we proposed a method for measuring the sound speed in the deep-sea first-layer sediment using a high-frequency submersible sub-bottom profiler. In this method, we obtained the reflection data of deep-sea sediments near the bottom using a wide-band narrow-beam single transducer and obtained the profile of deep-sea sediments using the reflection compression method. The first sediment layer was extracted according to the layer structure information, and the sound speed of the first sediment layer was directly measured. The transducer feasibility of the high-frequency submersible sub-bottom profiler operating at high pressure in deep sea was verified through high hydrostatic pressure tests in the laboratory. We designed a laboratory reflection compression measurement device to simulate the first layer of deep-sea sediments and verified the effectiveness of the measurement method. This method also was used to process deep-sea sediment data acquired by the Deep-Sea Warrior manned submersible. [ABSTRACT FROM AUTHOR]

Precise prediction of the hindered diffusion behavior of electroneutral particles in fibrous media plays a critical role in the development of drugs, polymer membranes, and porous electrodes. However, the random microstructure and unknown coupling relationship of multiple resistance mechanisms lead to the lack of a universal prediction model. In this work, a dual-resistance model is proposed by reconstructed pore-scale simulations, which presents the coexistence of steric and hydrodynamic resistances in the multiplication form. The simulation results show that the relationship between steric resistance and structural parameters (porosity, fiber radius, and particle radius) is exponential, while that for hydrodynamic resistance is polynomial. The dominant diffusion resistance is found to change from hydrodynamic to steric resistance with a decrease in porosity. The fluorescent polystyrene microsphere diffusivity in a series of SiO2 fibrous media is determined by single-particle tracking experiments, quantitatively confirming the dual-resistance model. The present model can be used for rapid diffusivity prediction and fibrous membrane and drug design. [ABSTRACT FROM AUTHOR]

As a computing service platform closer to users, fog computing has many advantages such as extremely low latency, good mobility, accurate location perception and wide distribution. It has developed rapidly in recent years. However, due to the wide distribution of fog nodes, complex network environments, and limited resources, the security of fog nodes is vulnerable to a variety of attacks, such as denial of service and abuse of resources. In order to effectively deal with these attacks, this paper proposes a quantum fog computing model based on blind quantum computation and verifiable quantum secret sharing. The model mainly relies on blind quantum computation to realize the security joint operation characteristics of multiple fog nodes, and the identity verifiable and channel detection protection features provided by the quantum secret sharing protocol, which can not only efficiently perform the functions of the classic fog computing, but also guarantee the security of information transmission and data calculation. Through the complete security analysis, the new quantum fog computing model proposed in this paper can effectively resist on a variety of fog computing attacks, thus achieving information security protection in both the content and process of fog computing. [ABSTRACT FROM AUTHOR]

In order to study the effect of different high heat input on the microstructure and properties of coarse-grained heat-affected zone (CGHAZ) of 500 MPa high-strength low-alloy steel, the welding thermal simulation experiments under different welding heat input conditions were carried out. The results show that as the heat input increases from 50 kJ·cm−1 to 400 kJ·cm−1, the acicular ferrite (AF) appeared to increase firstly and then gradually decreased. However, the grain boundary ferrite (GBF) and the granular bainite (GB) gradually decreased. The impact toughness of CGHAZ with 100 kJ·cm−1 showed the highest value, about 154 J, and the microhardness decreased slightly with the increase in heat input. The fracture mechanism changed from ductile fracture to cleavage fracture. Under the condition of 100 kJ·cm−1 heat input, the Mn–S–Al–Ti–Ca–O complex inclusions formed in the matrix can effectively induce the nucleation of AF in the CGHAZ, and the secondary AF can be induced by the primary AF sympathetically, thus improving the welding impact toughness. [ABSTRACT FROM AUTHOR]

With the development of the Augmented and Virtual Reality (AR/VR) technologies, massive biometric data are collected by different organizations. These data have great significance but also worsen the privacy risks. Electro-CardioGram (ECG)-based Identity Recognition (EIR) is a popular Biometric technology. An ECG record is an internal Biology feature of a person and has time continuity. Thus, compared with traditional Biometric methods like face recognition, EIR may be less vulnerable to attack. We propose an Autoencoder-based EIR system, called Personalized AutoEncoder (PerAE). PerAE maintains a small autoencoder model (called Attention-MemAE) for each registered user of a system. The Attention-MemAE enhances the autoencoder by using a memory module and two attention mechanisms. A user’s Attention-MemAE classifies the hearbeats of other users as anomalies. An Attention-MemAE can be updated when the distribution of the user’s ECG data is changed. By using personalized autoencoder, PerAE can improve the time efficiency and reduce the memory overhead. It improves the adaptability, scalability, and maintainability of EIR systems. Experiment results show that to train an Attention-MemAE with 90 $\%$ identification accuracy for a user, we can just take five minutes to collect the user’s ECG data (around 500 heartbeat samples). [ABSTRACT FROM AUTHOR]

In this paper, two efficient quantum image steganography protocols based on double-layer matrix coding are proposed. The first protocol is based on the high embedding efficiency of the classic Zhang Weiming, Zhang Xinpeng and Wang Shuozhong's steganography framework and matrix coding, combined with quantum image carrier, so that the new protocol not only has very high embedding efficiency but also has high security. The second protocol further proposes a more efficient quantum image steganography protocol, which not only achieves a higher embedding efficiency than the first protocol but also doubles the capacity of the first protocol. To reflect the practicality of these two protocols, we also designed dedicated quantum circuits to embed and extract secret information. Based on the IBMQ quantum experiment platform, we successfully ran the core circuits of the protocol and gave the corresponding results. The simulation results based on MATLAB and the mathematical analysis also show that the two new protocols not only have good imperceptibility but also have high embedding efficiency. [ABSTRACT FROM AUTHOR]

Self-humidification is becoming a popular strategy for water management in proton exchange membrane fuel cells (PEMFCs), owing to the advantages of decreased volume, cost, and parasitic power of the hydrogen fuel cell engine. Membrane dehydration is one of the key issues that seriously affect the performance and lifespan of PEMFCs under low humidity conditions. In this work, an electrospinning approach was employed to fabricate gas diffusion layers (e-GDLs) composed of nanosized carbon fibers with a nanoscale pore structure. Further, a vapor deposition of Dow Corning Sylgard 184 was utilized to apply a hydrophobic coating to enhance the hydrophobicity of the e-GDL. The fabricated e-GDL can help alleviate the dehydration of the catalyst-coated membrane by increasing the breakthrough pressure. The breakthrough pressure of the e-GDL is five folds higher than that of the current commercial GDL, owing to the combined effects of the nanostructure and enhanced hydrophobicity. This superior characteristic is expected to effectively alleviate membrane dehydration under low humidity conditions. In addition, the e-GDL has excellent elastic deformability, which can effectively alleviate the irreversible damage caused by the pre-tightening force in the stack assembly process, thus enhancing the durability and lifetime of PEMFCs. [ABSTRACT FROM AUTHOR]

Sub-bottom profiling traditionally uses low-frequency signals (less than 20 kHz) to examine layered structures of the bottom sediment in large depth, but it has some limitations in deep-sea surveying. The surficial sediment within several meters under the water–sediment boundary in the deep sea cannot be distinguished clearly. In this study, a high-frequency sub-bottom profiler (HFSBP) was developed and applied to a manned deep-submergence vehicle (DSV), named Deep-Sea Warrior, to obtain a centimeter-level resolution stratum of several meters in the deep-sea surficial sediment. Twelve diving tests were carried out, the diversity of surficial benthic profiles on the northern slopes of the South China Sea was shown up for the first time and as many as four layers profiles were obtained in the low bending canyon region, rock surface profiles, discontinuous stratum structures and thick surficial sediment in the deeper region. Continuous and clear stratum structures within a range of about 2 m on the seabed surface sediment were obtained in 11 of the 12 dives. As the dive sites took a certain dispersive distribution, it reflected that the stratum structure of surficial sediment was prevalent in the northern slopes area of the South China Sea for the most part. To verify the effectiveness of HFSBP, a laboratory test in an anechoic tank was performed, and the experiment results verified the layered ability and the thickness measurement stability of it. The comparison was performed with shipboard data of deep-sea sub-bottom profiler (SBP) Bathy-2010, and the HFSBP results were obviously better than those of Bathy-2010 measurement. The clear and continuous fine layered data obtained by HFSBP may help scientists in new area research in marine geophysics. [ABSTRACT FROM AUTHOR]

This paper proposes an efficiency quantum image steganography protocol based on improved exploiting modification direction algorithm (QIS-IEMD). The new methods of expanding modification range and dynamically sharing between subgroups are introduced in the new protocol. Compared with the quantum image steganography protocol based on EMD algorithm (QIS-EMD), secret information can be embedded on multiple bit planes after expanding pixel's modification range, and the carrier pixel groups can be dynamically shared to achieve higher embedding efficiency, embedding rate and larger capacity. In addition, in order to reflect the feasibility and practicability of QIS-IEMD, dedicated quantum circuits for embedding and extracting secret information are designed for it. Finally, the experimental results and detailed mathematical analysis prove that, compared with QIS-EMD, QIS-IEMD not only performs well in imperceptibility, but also significantly increases embedding efficiency, embedding rate and capacity. [ABSTRACT FROM AUTHOR]

A novel controlled flexible representation for quantum image(CFRQI) is firstly proposed in this paper based on flexible representation for quantum image (FRQI). The proposed CFRQI is able to effectively help the sender control the whole process of information transmission for better information security. Next, a novel secure controlled quantum image steganography algorithm is proposed by making full use of controlled access mechanism that comes with CFRQI. Compared with the previous quantum steganography algorithms, the new algorithm can make the sender control whether the receiver is enabled to correctly receive secret information or not for better imperceptibility. And it also can achieve better security by introducing the controlled access mechanism as an identity authentication system without the need of auxiliary information. Good applicability of the new algorithm is proved by the quantum circuits of embedding and extracting processes that are designed to implement. Furthermore, the new algorithm can effectively resist the phase-damping and amplitude-damping noises in quantum channel through theoretical analysis. Finally, the simulation experiment results are presented to prove our conclusions. [ABSTRACT FROM AUTHOR]

The quantum steganalysis faces more challenges than classical steganalysis owing to the support of quantum mechanical principles such as Heisenberg uncertainty principle and non-cloning theorem. In this paper, a novel quantum steganalysis protocol based on pure state is proposed, which adheres to the fundamental fact that classical steganography tends to change the probability distribution of the carrier, and the physical properties that the unknown quantum state discrimination process is sensitive to the distribution in quantum state discrimination. After utilizing accurate calculation on the geometric coherence and 1/2-affinity coherence to obtain the probability that the transmitted quantum states can be correctly discriminated, effective detection on covert communication can be achieved by comparing the detected distribution with theoretical distribution. Meanwhile, steganographic detection rate and false alarm rate are introduced as two significant performance evaluation parameters of quantum steganalysis. In this paper, the quantum steganalysis and performance evaluation targeting the BB84-based quantum steganography proposed by Martin are given in detail. The geometric coherence and 1/2-affinity coherence change substantially when the steganographic embedding rate is above 0.2, and a high steganographic detection rate and a low false alarm rate can be obtained according to the proposed protocol. Besides, the impact on QKD efficiency can be controlled by adjusting the detection rate or adopting sampling detection strategy. It proves that the proposed protocol has a satisfactory quantum steganalysis performance. [ABSTRACT FROM AUTHOR]

Side-channel analysis concerns cryptanalytic attacks that exploit the physical environment of cryptographic modules by analyzing leaking emanations and obtaining the encryption key. We propose a multiple-input, multilayer-perceptron-based method for classifying power traces, in which a probability is assigned to each class, indicating the likelihood that each trace corresponds to the label for further recovering the key. [ABSTRACT FROM AUTHOR]

With an increase of service users' demands on high quality of services (QoS), more and more efficient service computing models are proposed. The development of cloud computing, fog computing, and edge computing brings a number of challenges, e.g., QoS optimization and energy saving. We do a comprehensive survey on QoS optimization and energy saving in cloud computing, fog computing, edge computing, and IoT environments. We summarize the main challenges and analyze corresponding solutions proposed by existing works. This survey aims to help readers have a deeper understanding on the concepts of different computing models and study the techniques of QoS optimization and energy saving in these models. [ABSTRACT FROM AUTHOR]

With an increase of service users' demands on high quality of services (QoS), more and more efficient service computing models are proposed. The development of cloud computing, fog computing, and edge computing brings a number of challenges, e.g., QoS optimization and energy saving. We do a comprehensive survey on QoS optimization and energy saving in cloud computing, fog computing, edge computing, and IoT environments. We summarize the main challenges and analyze corresponding solutions proposed by existing works. This survey aims to help readers have a deeper understanding on the concepts of different computing models and study the techniques of QoS optimization and energy saving in these models. [ABSTRACT FROM AUTHOR]

Maneuver models are dedicated to accurate representation of unknown motion pattern. However, for near space hypersonic jump gliding targets of high speed, diverse movement pattern, and mobility, the conventional maneuver models are difficult to describe the complex movement characteristics, and then leading to high and unstable tracking error. In order to solve this problem, a new model is proposed based on the attenuation of oscillation function. The core of the model is to consider the target acceleration as a zero mean random process with attenuation oscillation. With the model, the equations of the maneuvering target are constructed and the system dynamic error of this model was deduced taking Kalman filter as the filtering algorithm. Moreover, the corresponding relations among parameters are discussed, and an adaptive method is proposed for setting parameters appropriately in the situations when a priori information is unknown. In this way, the parameters can be adjusted online through jumping point identification. Theoretical analysis and simulation experiments are conducted to demonstrate the effectiveness of the proposed model. Comparing to commonly used models, it shows lower filtering errors tracking near space hypersonic jump gliding targets. Finally, the rationality and validity of the parameters adaptive method are explained. [ABSTRACT FROM AUTHOR]

Arsenic (As) is a carcinogenic metalloid that poses serious health and environmental threats to human. We explored the potential of Dahlia pinnata Cav., which is a known ornamental plant, for phytoremediation of As. Impacts of increasing As concentrations (0–120 µM) on growth and biochemical parameters of D. pinnata were evaluated. At lower As stress (5 µM—a concentration which is toxic for many plants species), growth performance of D. pinnata remained stable, whereas higher As concentration lead to an obvious deleterious effect, with no growth after 4 weeks of As exposure (at concentration higher than 80 µM As). Roots were found to accumulate high levels of As. Chlorophyll a, b and carotenoids contents were enhanced at low concentration and at higher As concentration significant decrease was observed. Activities of antioxidant enzymes like catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and glutathione S-transferase (GST) were found to be affected variably by As exposure, in D. pinnata. In conclusion, D. pinnata is a nonaccumulator however, the As tolerance limit (5 µM = 370 µg L−1), growth performance and tendency of the plant to keep most of absorbed As in its root make it a potential candidate for the phytostabilization purposes of As-contaminated sites. [ABSTRACT FROM AUTHOR]

Lateral flow assays (LFAs) are promising candidates in biomedical diagnosis fields due to their rapid, low-cost, and portable features. However, improving their sensitivity remains challenging due to the unclear roles of capture probes with different distribution formats on the particle transfer and capturing in the test line. Therefore, we designed experiments and observed an asymmetrical U-shaped distribution of control probes throughout the NC membrane thickness. Based on this outcome, a two-dimensional mathematical model based on the Langmuir surface reaction kinetics was developed to investigate the effect of capture probe distributions on LFA performance. A two-dimensional model was qualitatively validated by comparing with the experimental results and the simulations of the reported one-dimensional model. Then, a higher detection signal was achieved by using the U-shaped distribution of capture probes throughout the NC membrane thickness instead of a uniform distribution. Furthermore, when the NC membrane thickness was less than 110 μm, the ratio of the detection signal in the visible region to the signal in the total section at the test line was above 13%. A thin NC membrane will produce a strong detection signal in the visible region at the test line. The developed model is capable of providing direct predictions in designing highly sensitive LFAs. [ABSTRACT FROM AUTHOR]

Quantum image steganography is the art and science of hiding secret information into quantum carrier images. This paper proposes a novel quantum image steganography algorithm based on an efficient embedding technique of exploiting modification direction. For convenience, this embedding technique is referred to the EMD embedding. In the EMD embedding, it is clear that each carrier pixel-group of the carrier image contains N pixels and each secret digit of secret information belongs to the (2N + 1)-ary notational system, where N is a system parameter. The embedding process is that at most only one pixel of the carrier pixel-group will be either increased by 1 or decreased by 1. The new algorithm takes advantage of the EMD embedding owning high embedding efficiency that the (2N + 1) different modifications to N carrier pixels represent the value of the secret digit. In addition, designing the dedicated quantum circuit for the EMD embedding contributes to better understanding the process of the new algorithm. Experimental simulation based on MATLAB shows that the new algorithm has good performance on imperceptibility, security, embedding efficiency and embedding capacity. [ABSTRACT FROM AUTHOR]

Shale gas is becoming an increasingly promising alternative energy resource because of its high efficiency and environment-friendly characteristic. The amount of adsorbed gas on the shale matrix surfaces and dissolved gas in the shale matrix bulk is the dominant factor in the long-term productivity of shale reservoir. Although experimental measurements have been extensively carried out to investigate the gas adsorption and diffusion properties in the shale matrix, they cannot provide the detailed information on the microscopic transport mechanism of shale gas during the gas production process. Molecular simulation can accurately visualize the gas adsorption/desorption and diffusion processes in the shale matrix. In the present study, the recent research advances of molecular simulation on gas adsorption/desorption and diffusion in the shale matrix are reviewed. Firstly, the density functional theory (DFT) for shale gas molecule desorption/adsorption on the surface of the matrix crystal is illustrated. Then, the grand canonical Monte Carlo (GCMC) method predicting the amount of shale gas desorption/adsorption in the shale matrix crystal is introduced. Finally, molecular dynamics simulation (MD) for gas diffusion in the shale matrix is elucidated. Further developments of the molecular simulation method in shale gas production are also discussed. [ABSTRACT FROM AUTHOR]

This paper proposed a secure authenticated quantum video steganography protocol with large capacity. The new protocol can embed secret quantum information into carrier quantum video, and expand the embedding capacity to a large extent. It also manages to accomplish quantum information steganography process based on unique features of video as well as authentication mechanism for better security. Finally, the simulation experiment proves that the new protocol not only has good performance on imperceptibility and security, but also owns a large capacity. [ABSTRACT FROM AUTHOR]

Lateral flow assays (LFAs) have attracted considerable attention in biomedical diagnostics. However, it's still challenging to achieve a high detection sensitivity and extensive working range, mainly because the underlying mechanism of complex reaction processes in LFAs remains unclear. Many mathematical models have been developed to analyze the complex reaction processes, which are only qualitative with limited guidance for LFA design. Now, a semi-quantitative convection-diffusion-reaction model is developed by considering the kinetics of renaturation of nucleic acids and the model is validated by our experiments. We established a method to convert the LFA design parameters between the simulation and experiment (i.e., inlet reporter particle concentration, initial capture probe concentration, and association rate constant), with which we achieved a semi-quantitative comparison of the detection limit and working range between simulations and experiments. Based on our model, we have improved the detection sensitivity and working range by using high concentrations of the inlet reporter particles and initial capture probe. Besides, we also found that target nucleic acid sequences with a high association rate constant are beneficial to improve the LFA performance. The developed model can predict the detection limit and working range and would be helpful to optimize the design of LFAs. [ABSTRACT FROM AUTHOR]

An anti-noise bidirectional quantum steganography protocol with large payload protocol is proposed in this paper. In the new protocol, Alice and Bob enable to transmit classical information bits to each other while teleporting secret quantum states covertly. The new protocol introduces the bidirectional quantum remote state preparation into the bidirectional quantum secure communication, not only to expand secret information from classical bits to quantum state, but also extract the phase and amplitude values of secret quantum state for greatly enlarging the capacity of secret information. The new protocol can also achieve better imperceptibility, since the eavesdropper can hardly detect the hidden channel or even obtain effective secret quantum states. Comparing with the previous quantum steganography achievements, due to its unique bidirectional quantum steganography, the new protocol can obtain higher transmission efficiency and better availability. Furthermore, the new algorithm can effectively resist quantum noises through theoretical analysis. Finally, the performance analysis proves the conclusion that the new protocol not only has good imperceptibility, high security, but also large payload. [ABSTRACT FROM AUTHOR]

The traditional image authentication technique generally determines the image attribution by extracting specific features and combining the similarity calculation algorithm. Because of the selected features dimensions, characterization and other factors, the accuracy and speed of image authentication have been restricted. In this paper, Recog-Net, an end-to-end image authentication model based on convolution neural network has been proposed. Deep residual network is chosen as the features extractor. Mahalanobis distance and threshold method are used to complete the image authentication. Experiments show that the performance of the extractor's features, compared with the traditional features and the features of other convolution neural network architectures, is more excellent, with a high degree of generality, recognition rate and robustness, still having these advantages even after a substantial compression. The Recog-Net for image authentication is able to accurately authenticate the images tampered with certain range. [ABSTRACT FROM AUTHOR]

The Internet has become an increasingly appealing medium for telecare medicine information systems (TMISs). However, the open nature of the Internet poses serious security threats and vulnerabilities to TMISs and privacy concerns to the patients and medical personnel. This work proposes a hybrid quantum key distribution protocol to provide security in TMISs, leveraging the key agreement of classical and quantum key distribution. Our protocol induces low energy and computation overheads to achieve privacy and trusted operations for TMISs. This is because quantum key distribution employs the principles of quantum mechanics rather than computational complexity, to avoid various attacks such as the man-in-the-middle attacks, the replay attacks and the passive attacks. Meanwhile, classical cryptography can be used to achieve user authentication efficiently. Therefore, our protocol may be available with the rapid developments of extensive experiments for quantum key distribution. [ABSTRACT FROM AUTHOR]

Copyright protection for quantum image is an important research branch of quantum information technology. In this paper, based on quantum log-polar image (QUALPI), a new quantum watermark algorithm is proposed to better protect copyright of quantum image. In order to realize quantum watermark embedding, the least significant qubit (LSQb) of quantum carrier image is replaced by quantum watermark image. The new algorithm has good practicability for designing quantum circuits of embedding and extracting watermark image respectively. Compared to previous quantum watermark algorithms, the new algorithm effectively utilizes two important properties of log-polar sampling, i.e., rotation and scale invariances. These invariances make quantum watermark image extracted have a good robustness when stego image was subjected to various geometric attacks, such as rotation, flip, scaling and translation. Experimental simulation based on MATLAB shows that the new algorithm has a good performance on robustness, transparency and capacity. [ABSTRACT FROM AUTHOR]

As one of important multimedia forms in quantum network, quantum video attracts more and more attention of experts and scholars in the world. A secure quantum video steganography protocol with large payload based on the video strip encoding method called as MCQI (Multi-Channel Quantum Images) is proposed in this paper. The new protocol randomly embeds the secret information with the form of quantum video into quantum carrier video on the basis of unique features of video frames. It exploits to embed quantum video as secret information for covert communication. As a result, its capacity are greatly expanded compared with the previous quantum steganography achievements. Meanwhile, the new protocol also achieves good security and imperceptibility by virtue of the randomization of embedding positions and efficient use of redundant frames. Furthermore, the receiver enables to extract secret information from stego video without retaining the original carrier video, and restore the original quantum video as a follow. The simulation and experiment results prove that the algorithm not only has good imperceptibility, high security, but also has large payload. [ABSTRACT FROM AUTHOR]