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Trust is a fundamental condition for secure communication, and the trust evaluation of participating nodes in quantum communication networks is a prerequisite to guarantee the security of various quantum communication protocols. However, existing quantum trust models are based on a trusted third-party central node to complete trust assessment process, once a malicious attacker successfully attacks the third-party central node, the trust mechanism of the whole quantum communication network will no longer be secure. In this paper, a quantum semi-trust evaluation model with graph-based quantum walk teleportation is proposed to enhance the quantum communication node’s security and privacy. The communication nodes do not need to prepare quantum entangled states in advance, and only simple quantum operation are needed to evaluate each other's node trust values. The quantum circuit diagram required for model building is presented, and the security analysis shows that this model has better anti-attack capability and higher particle efficiency. [ABSTRACT FROM AUTHOR]

The northwestern sub-basin of South China Sea (SCS) is a unique tectonic unit formed in the early spreading of the SCS. The northwestern Sub-basin has a series of complex geological structures such as seamounts and fault zones surrounded by the Xisha Trough, the Zhongsha Massif, and the Pearl River Valley. These extensional structures and magmatic activity in the northwestern sub-basin are closely related to the lithospheric structure and its deformation. However, details of the deep lithosphere structure are still poorly known. Here, we obtained detailed data of water and Moho depth using sonar buoys, Extended Spread Profiles (ESP), Ocean Bottom Seismometer (OBS), both Multi-beam and land-sea joint seismic surveys in the northwestern sub-basin and its surrounding areas. Then we adopted a thermal isostasy method to calculate the depth of the Lithosphere-Asthenosphere Boundary (LAB) in the northwestern sub-basin of the SCS and its surrounding regions. Results show that the range of LAB depth is ~25–110 km. The shallowest burial depth is 25–60 km occurring in the ocean basin. The depth increases to 60–110 km toward the continental margin. The lithospheric structure on the north and south sides of the Xisha Trough is symmetrical and shows the deep structure and thermal features of aborted rifts. The LAB depth in the Zhongsha Trough and the Zhongsha Massif increased from 60 to 70 km southwestwards, consistent with the trend of surface morphology. The LAB depth to the west side of the Pearl River Valley is 60–80 km, and the thinning of the lithosphere is related to the distribution of faults, depressions and the magmatic activity. The LAB depth in the northwestern sub-basin and the eastern sub-basin is less than 60 km with the thinnest part being less than 46 km. Combining ocean drilling, seismic investigation, and seafloor topography, we show that the ocean basin of the northwestern sub-basin of the SCS locates within the 46 km isobath of the LAB. The formation of the rifted valleys and discrete blocks surrounding the ocean basins is both controlled by the regional tectonic movement and the deep thermal state, where their lithospheric structures show strong heterogeneity. [ABSTRACT FROM AUTHOR]

A novel molecular model of vulcanized styrene-butadiene rubber (SBR) was developed and experimentally verified to elucidate the enhanced tribological performance of vulcanized SBR over raw SBR. Vulcanization was modeled by cross- or self-linkages of sulfur (S) atoms with carbon (C) atoms in molecular chains. Frictional models were developed for vulcanized and raw styrene-butadiene rubber-ferrum (SBR-Fe) to study the atomic behavior at the frictional interface. The results at the atomic scale show considerable reductions in the coefficient of friction (COF) and the interfacial temperature of approximately 45.8% and 13.27% for the vulcanized SBR matrix, respectively, from those of raw SBR. In addition, the relative concentration (RC), the radial distribution function (RDF) and interaction energy of the vulcanized SBR are 21.61%, 6.68% and 60.12% lower than those of the raw SBR, respectively. The resulting decrease in the real contact area, adhesion and contact temperature at the interface can significantly improve the tribological properties of the vulcanized SBR over those of raw SBR. The results of this research study show how vulcanization can enhance the tribological properties of polymer composites at the atomic scale. [ABSTRACT FROM AUTHOR]

To promote the development of a green environment, it is necessary to build a friendly environment for green travel and increase the use of green resources. Methods based on remote sensing image processing and feature analysis have become one of the main ways to obtain ground information, and have been widely used and promoted. Therefore, ground targets the accuracy of object recognition and features have been significantly improved. In the lightweight image of the city, the terrain occupies almost 80% of the buildings and roads. Urban buildings play an important role in supporting the operation, management and planning of the city. An important technology for the construction of digital towns in the future is the city. Building identification, therefore, the research of building identification is more important in the development of the city. With the widespread application of artificial intelligence deep learning and the popularization of smart technologies, the digital images generated by the Internet and mobile smart terminals have exponentially increased. Image data provides users with a comfortable experience and convenient services, but it also brings many challenges. How to filter out the photos we are interested in from a large amount of image data and find the content we need is a data difficulty. In computer vision research, image search systems can solve the problem of searching for the same content in many digital images. This paper applies deep learning and lightweight images to search systems to promote the development of urban building recognition. [ABSTRACT FROM AUTHOR]

To improve the tribological performance of the oil distribution plate of the plunger pump under dry sliding wear and temperature rise conditions during the start–stop stage and reduce its cost, a polyamide imide (PAI)/polyimide (PI)–Polytetrafluoroethylen (PTFE) coating filled by three different content of tungsten carbide (WC)/Tantalum (Ta) were designed. The composite polymer coating was prepared on the surface of 1010 steel and AS20 aluminum substrate by liquid spraying, and its tribological properties under different temperatures and lubrication media were investigated. The results showed that the tribological properties of the coating were influenced by the hardness of the substrate, the content of the filled particles, the ambient temperature, and the lubricating medium. The hardness of the coating increased with substrate hardness and WC content. Under the condition of sliding wear at room temperature, the wear mechanism was mainly abrasive wear and adhesive wear. The wear rate of the coating decreased with an increase in WC content. The coating with 5% WC addition had the lowest wear rate on 1010 steel and AS20 aluminum substrate. Under the same coating condition, the tribological properties of the 1010 alloy steel were lower than those of the AS20 aluminum. The pear groove and adhesion of the coating increased with temperature. Compared with the CuPb24Sn at 100°C, coating on the surface of 1010 steel significantly reduce the coefficient of friction (CoF) and wear rate. The CoF and wear rate under dry sliding wear were reduced by 57.5 and 8.7% and those under oil lubrication were reduced by 45.7 and 11.1%, respectively. The supporting effect of the matrix, the bonding of the internal particles in the coating, the softening degree of polymer materials such as resin, and the lipophilicity of the coating are the main reasons. [ABSTRACT FROM AUTHOR]

A 3D thermal-mechanical elastic-plastic FE wear model for investigating tool wear in cross wedge rolling (CWR) process was developed and validated in this paper, especially considering the influence of temperature on tool parameters under the circumstance of laboratory. Tool wear, contact stress, and contact temperature along tool wedge ridge path under different initial billet temperatures were investigated. To study the influence of initial billet temperature, the tool wear is considered as the combined effects of tool thermal softening behavior and resistance to workpiece plastic deformation. Unit wear is firstly introduced to describe the effect of the material thermal softening behaviors on tool wear. Results show that tool wear occurs severely along the wedge ridge and reaches its maximum as the workpiece is rolled at a half round. The minimum tool wear can be achieved using appropriate initial billet temperature. The proposed methodology may help CWR manufacturers to design and produce tools that exhibit less wear. [ABSTRACT FROM AUTHOR]

Guangdong Province in the central Cathaysian Block has two world-class metallogenic belts, namely, the Nanling and Southeastern Coastal Metallogenic Belts (NLMB and SCMB), which are spatially coincide with the major regional Ganjiang and Zhenghe-Dapu Fault Zones (GJFZ and ZDFZ). However, what roles the faults played in mineral deposition and magmatism is unclear. Using ambient noise tomography, we obtain a 3-D whole-crust shear wave velocity model. By combining available regional geophysical models, we characterize the architecture of the regional shallow lithosphere and infer its possible tectonic connection to magmatic sources, pathways and surface deposition. The results show that the study area is loosely divided by the two major faults, the GJFZ and ZDFZ, into distinct velocity domains. In the north high Vs and low Vp/Vs crust in the NLMB imply crustal remelting, which leads to the general felsic composition. In the coastal area, the lower crustal high Vs anomaly is attributed to upwelling melts associated with Cretaceous magmatic activity. Between mineral belts, a swath of crustal low-velocity zones extend into the uppermost mantle, manifesting partial melting related to upwelling magmas that may hint at a deep origin of magma from subcrustal lithosphere and likely feed surface mineral deposits through major faults. Secondary NW-trending faults coincide with low velocities and facilitated magmatic migration. A correlation between coastward extension of low velocities and younging of the Jurassic and Cretaceous magmatism is suggestive of a combined effect of slab rollback and a change in the direction of the Paleo-Pacific subduction system. We speculate a regional fault-control model in the central Cathaysian Block for the spatial-temporal evolution of regional deformation and magmatism during the middle Mesozoic. [ABSTRACT FROM AUTHOR]

Serpentinization is an important phenomenon for understanding the water cycle and geodynamics of subduction zones in the upper mantle. In this study, we evaluate quantitatively the degree of serpentinization using the seismic velocity. The results show that serpentinization mainly occurs in the forearc mantle wedge along the subducted oceanic crust, and the degree of serpentinization in the forearc mantle wedge of Kyushu is strongly heterogeneous and varies from 0 to 12 %, containing about 0-1.8 % water contents. In general, the degree of serpentinization gradually decreases with depth from 40 to 80 km and the largest degree usually occur in about 40-50 km depth. Localized high anomalies of serpentinization are revealed in the northern and southern portions of Kyushu, respectively. We suggest that in the northern portion of the forearc mantle wedge, the water contents are relatively large, which might result from the abundant fractures and cracks with more fluids in the subducting slab because of the subduction of Kyushu-Palau ridge and the sudden change in its subduction angle of Philippine Sea lithosphere. But the high degree of serpentinization in the southern portion is closely associated with the active left-lateral shear zone revealed by global positioning system site velocities and earthquake focal mechanisms. In addition, the present results also display that the low degree of serpentinization in the central domain of the forearc mantle wedge is consistent with the location of anomalous arc volcano. The distribution of water contents is closely associated with the degree of serpentinization in the forearc mantle wedge. [ABSTRACT FROM AUTHOR]

DdCAD-1 is a novel Ca2+-dependent cell adhesion molecule that lacks a hydrophobic signal peptide and a transmembrane domain. DdCAD-1 is expressed by the social amoeba Dictyostelium discoideum at the onset of development. It is synthesized as a soluble protein and then transported to the plasma membrane by contractile vacuoles. Here we describe the novel features of the solution structures of Ca2+-free and Ca2+-bound monomeric DdCAD-1. DdCAD-1 contains two β-sandwich domains, belonging to the βγ-crystallin and immunoglobulin fold classes, respectively. Whereas the N-terminal domain has a major role in homophilic binding, the C-terminal domain tethers the protein to the cell membrane. From structural and mutational analyses, we propose a model for the Ca2+-bound DdCAD-1 dimer as a basis for understanding DdCAD-1–mediated cell-cell adhesion at the molecular level. Our results provide new insights into Ca2+-dependent mechanisms for cell-cell adhesion. [ABSTRACT FROM AUTHOR]

Approaches to reliably predict the developmental potential of embryos and select suitable embryos for blastocyst culture are needed. The development of time-lapse monitoring (TLM) and artificial intelligence (AI) may help solve this problem. Here, we report deep learning models that can accurately predict blastocyst formation and usable blastocysts using TLM videos of the embryo's first three days. The DenseNet201 network, focal loss, long short-term memory (LSTM) network and gradient boosting classifier were mainly employed, and video preparation algorithms, spatial stream and temporal stream models were developed into ensemble prediction models called STEM and STEM+. STEM exhibited 78.2% accuracy and 0.82 AUC in predicting blastocyst formation, and STEM+ achieved 71.9% accuracy and 0.79 AUC in predicting usable blastocysts. We believe the models are beneficial for blastocyst formation prediction and embryo selection in clinical practice, and our modeling methods will provide valuable information for analyzing medical videos with continuous appearance variation. Liao et al. propose a deep learning model to predict blastocyst formation using TLM videos following the first three days of embryogenesis. The authors develop an ensemble prediction model, STEM and STEM+, which were found to exhibit 78.2% and 71.9% accuracy at predicting blastocyst formation and useable blastocysts respectively. [ABSTRACT FROM AUTHOR]

The Guangxi Gulf of Tonkin (GXGT) is rich in mineral, oceanic energy, and biological resources; however, it has not attracted much attention. Based on ECOMSED, a high-resolution three-dimensional numerical model is constructed in this study, and the accuracy is validated using long-term observational data. The results showed that the GXGT is dominated by regular diurnal tide and mixed mainly diurnal tidal currents and some regions to the northwest and south of Weizhou Island are dominant by mixed mainly semi-diurnal tidal currents. Furthermore, the rotation direction of O1 is found to be counter-clockwise and clockwise in the western and eastern domains, respectively, whereas the rotation directions of the other three tidal constituents are clockwise and counter-clockwise in the open sea and coastal bays, respectively. Similarly, the propagation direction of the tidal energy flux of O1 (northwestward) is different from them of the other three tidal constituents (northeastward) in the western GXGT. On the other hand, the propagation directions of the four tidal constituents are all northeastward in the eastern GXGT. A comparison of the reference run with the summed-up effect of six runs, where each of the tidal constituents has been considered separately, revealed that the nonlinear effect due to the interaction of the six tidal constituents cannot be neglected in the GXGT, especially in the western GXGT. Interestingly, energy input from wind to O1 is larger than that to M2 whereas the tidal dissipation of O1 is less than that of M2 at BBL. Additionally, tidally induced residual currents mostly flow westward in the GXGT, with clockwise eddies present outside the Qinzhou Bay and Tieshan Port. Driven by the monsoon wind, the current structure and strength in the GXGT have obvious seasonal variation. And sensitive experiments show that the residual currents in the GXGT are deeply influenced by the monsoon wind and bottom topography. [ABSTRACT FROM AUTHOR]

Cocoa fermentation is an essential step for chocolate production whereby flavor potential is generated and bitterness and astringency are moderated. To facilitate fermentation research in laboratories geographically distant from cocoa-growing regions, and to simplify and control the fermentation system, a laboratory fermentation model system was developed. The model system consisted of dried unfermented beans, artificial pulp medium, and laboratory incubator to control temperature and aeration. The model system developed in this study showed a succession of key microorganisms including Saccharomyces cerevisiae, Lactobacillus plantarum, Lactobacillus fermentum, Acetobacter pasteurianus, and Acetobacter tropicalis. The pH of cocoa beans decreased to an acceptable final pH (4.8). Sugars were well consumed and acetic acid and ethanol were produced during fermentation. Desirable volatile compounds including phenylethyl alcohol, acetoin, 2-phenylethyl acetate, and 3-methylbutyl acetate increased in the cocoa beans during fermentation. In addition, the concentration of polyphenols decreased with fermentation. These results lead to the conclusion that the model system developed in this study was able to simulate the microbial and chemical changes occurring in in situ cocoa fermentation. This laboratory-scale model system will enable systematic examination of the effects of process parameters on fermented bean quality. [ABSTRACT FROM AUTHOR]

A method of path planning based on laser cladding process characteristics was proposed, which can improve the machining efficiency and the quality of surface parts. The effective defocusing amount range of the laser cladding process is determined by the coaxial model of laser and powder interaction and the coaxial powder feeding experiments. The points cloud data of the cladding surface was obtained by the 3D scanner and the point set on the cladding path was obtained by the point clouds slicing method, utilizing equal bow height sparse trajectory point set. And then the NURBS (non-uniform rational B-splines) surface was fitted to the cladding surface and its differential geometrical characteristics were analyzed to determine the vector processing point and biased it to a certain distance to obtain the trajectory point of the gun head. The complex movement of laser gun head with continuous variable altitude is determined by the robot flexible processing characteristics, meanwhile, keeping the laser gun head and the cladding surface processing point normal vector on the same line. From the cladding experiments and the quantitative analysis of the experimental samples, good quality of the cladding layer on the curved surface was achieved. Also, the reliability and practicability of the method were verified, thus providing a good reference for remanufacturing of other surface parts. [ABSTRACT FROM AUTHOR]

Long-term passive source ocean bottom seismograph (OBS) observatory is challenging due to various technical difficulties. In order to gain experience in this field, and to reveal the lithospheric structure beneath the extinct ridge in the central South China Sea (SCS), we carried out a passive source OBS array experiment, which includes 18 OBSs, in the deep portion of SCS. Here we present the instrumentation, the OBS deployment and recovery of this experiment, and more importantly, the data quality evaluated by a number of approaches. Through processing and inspecting waveforms from global, regional and local earthquakes, we find that most of recovered OBSs have good data quality with discernible main phases. The ambient noise analyses of OBS recordings show that their noise is higher than the global average, and the horizontal component is noisier than the vertical, indicating current impacts on horizontal components are more severe. In the period range of 5 -10 s, there is a noise notch for the SCS OBSs, and noise levels of horizontal components are comparable to the vertical. This feature, which is not seen at OBS stations in open ocean, suggests the distant sources for double frequency microseism in this marginal sea are not significant. In addition, we successfully determined the orientations for 7 OBSs by investigating their Rayleigh wave polarizations; and we demonstrated the dispersion feature of Rayleigh waves through the frequency-time analysis. Finally, we summarized lessons learned from this experiment regarding the passive source OBS investigations in SCS. [ABSTRACT FROM AUTHOR]