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The HY-2B satellite, equipped with the scanning microwave radiometer (SMR), was launched on 25 October 2018 and began observation on 30 October 2018. With the SMR data, we retrieved the sea surface...

For high wind speeds (7–22 m s−1), a semi-theoretical model for retrieving sea surface salinity (SSS) is derived from the version V3.0 of Aquarius data. In the model, the sea surface bright...

Reactive material projectiles can be an extremely efficient lethality enhancement technology that incorporates the defeat mechanisms of chemical energy and kinetic energy. This paper presents such a research on the enhanced ignition behavior of reactive material projectiles impacting a fuel-filled tank. Firstly, the ignition process description of the fuel-filled tank impacted by inert metal and reactive material projectiles is presented. Secondly, ballistic impact experiments are performed to investigate the ignition effects of the fuel-filled tank impacted by reactive material versus tungsten alloy projectiles with mass matched. The fuel tank used for the experiments is a cylindrical steel casing structure filled with aviation kerosene and sealed with aluminum cover plates on both ends using screw bolts. The experimental results indicate that, compared with impacts from tungsten alloy projectiles, there is dramatically enhanced structural damage to the fuel-filled tank and an enhanced ignition effect caused by reactive material projectile impacts. Finally, an analytical model is developed, by which the effects of the aluminum cover plate thickness on critical structural failure energy of the fuel-filled tank and the total energy of the reactive material projectile deposited into the fuel-filled tank are discussed. The analysis shows a good agreement with the experiments. Keywords: Reactive materials, Fuel-filled tank, Chemical energy release, Ignition mechanism

Spring viremia of carp virus (SVCV) is a highly pathogenic Vesiculovirus in the common carp. The phosphoprotein (P protein) of SVCV is a multifunctional protein that acts as a polymerase cofactor and an antagonist of cellular interferon (IFN) response. Here, we report the 1.5-Å-resolution crystal structure of the P protein central domain (P(CD)) of SVCV (SVCV(PCD)). The P(CD) monomer consists of two β sheets, an α helix, and another two β sheets. Two P(CD) monomers pack together through their hydrophobic surfaces to form a dimer. The mutations of residues on the hydrophobic surfaces of P(CD) disrupt the dimer formation to different degrees and affect the expression of host IFN consistently. Therefore, the oligomeric state formation of the P protein of SVCV is an important mechanism to negatively regulate host IFN response. IMPORTANCE SVCV can cause spring viremia of carp with up to 90% lethality, and it is the homologous virus of the notorious vesicular stomatitis virus (VSV). There are currently no drugs that effectively cure this disease. P proteins of negative-strand RNA viruses (NSVs) play an essential role in many steps during the replication cycle and an additional role in immunosuppression as a cofactor. All P proteins of NSVs are oligomeric, but the studies on the role of this oligomerization mainly focus on the process of virus transcription or replication, and there are few studies on the role of P(CD) in immunosuppression. Here, we present the crystal structure of SVCV(PCD). A new mechanism of immune evasion is clarified by exploring the relationship between SVCV(PCD) and host IFN response from a structural biology point of view. These findings may provide more accurate target sites for drug design against SVCV and provide new insights into the function of NSV(PCD).

Interferon (IFN) production activated by phosphorylated interferon regulatory factor 7 (IRF7) is a pivotal process during host antiviral infection. For viruses, suppressing the host IFN response is beneficial for viral proliferation; in such cases, evoking host-derived IFN negative regulators would be very useful for viruses. Here, we report that the zebrafish rapunzel 5 (RPZ5) protein which activated by virus degraded phosphorylated IRF7 is activated by TANK-binding kinase 1 (TBK1), leading to a reduction in IFN production. Upon viral infection, zebrafish rpz5 was significantly upregulated, as was ifn, in response to the stimulation. Overexpression of RPZ5 blunted the IFN expression induced by both viral and retinoic acid-inducible gene I (RIG-I) like-receptor (RLR) factors. Subsequently, RPZ5 interacted with RLRs but did not affect the stabilization of the proteins in the normal state. Interestingly, RPZ5 degraded the phosphorylated IRF7 under TBK1 activation through K48-linked ubiquitination. Finally, the overexpression of RPZ5 remarkably reduced the host cell antiviral capacity. These findings suggest that zebrafish RPZ5 is a negative regulator of phosphorylated IRF7 and attenuates IFN expression during viral infection, providing insight into the IFN balance mechanism in fish. IMPORTANCE The phosphorylation of IRF7 is helpful for host IFN production to defend against viral infection; thus, it is a potential target for viruses to mitigate the antiviral response. We report that the fish RPZ5 is an IFN negative regulator induced by fish viruses and degrades the phosphorylated IRF7 activated by TBK1, leading to IFN suppression and promotion of viral proliferation. These findings reveal a novel mechanism for interactions between the host cell and viruses in the lower vertebrate.

Fibroblast growth factor receptor (FGFR) 3 is one of the four distinct membrane-spanning tyrosine kinases required for proper skeletal development. In fish, the role of FGFR3 is still unclear. In this article, we reveal that zebrafish FGFR3 is a negative regulator of interferon (IFN) production in the innate immune response by suppressing the activity of TANK-binding kinase 1 (TBK1) in the process of virus infection. qPCR experiments demonstrate that the transcriptional level of cellular FGFR3 was upregulated by infection with spring viremia of carp virus (SVCV), indicating that FGFR3 might be involved in the process of host cell response to viral infection. Then, overexpression of FGFR3 significantly impeded the IFN promoter activity induced by a stimulator. In addition, the capabilities of a retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) system to activate IFN promoter were decreased during the overexpression of FGFR3. Subsequently, FGFR3 decreased the phosphorylation of interferon regulatory factor 3 (IRF3) and mediator of IRF3 activation (MITA) by TBK1. These findings suggest that zebrafish FGFR3 is a negative regulator of IFN by attenuating the kinase activity of TBK1, leading to the suppression of IFN expression.

Viral infection activates the transcription factor IFN regulatory factor 7 (IRF7), which plays a critical role in the induction of IFNs and innate antiviral immune response. How virus-induced IFN signaling is controlled in fish is not fully understood. In this study, we demonstrate that N-myc downstream-regulated gene 1a (NDRG1a) in zebrafish plays a role as a negative regulator for virus-triggered IFN induction. First, the activation of the IFN promoter stimulated by the polyinosinic-polycytidylic acid or spring viremia of carp virus was decreased by the overexpression of NDRG1a. Second, NDRG1a interacted with IRF7 and blocked the IFN transcription activated by IRF7. Furthermore, NDRG1a was phosphorylated by TANK-binding kinase 1 (TBK1) and promoted the K48-linked ubiquitination and degradation of IRF7. Finally, the overexpression of NDRG1a blunted the transcription of several IFN-stimulated genes, resulting in the host cells becoming susceptible to spring viremia of carp virus infection. Our findings suggest that fish NDRG1a negatively regulates the cellular antiviral response by targeting IRF7 for ubiquitination and degradation, providing insights into the novel role of NDRG1a on the innate antiviral immune response in fish.

The air volume fraction (AVF) of a sea foam layer is a key parameter that affects the microwave emissivity and brightness temperature of the sea surface. To extract AVF of a sea foam layer from the measured emissivity data at microwave frequencies, a novel retrieval method is developed based on the spectral representation of effective dielectric constant of sea foam composites media, with the volume fraction of constituents and the geometry of foam microstructure included in the spectral function. In the retrieval method, the cost function of emissivity is constructed with two constraints: one is the first two moments of the spectral function and the other is derived from the spectral representation of coated spherical composites. We tested the inverse method using the simulation data of a known emissivity model with Gaussian noise. Good agreement is obtained between the inverse results and the known AVF of sea foam from the simulated emissivity data with varying sea surface temperature, salinity, and incident angle. Finally, the proposed method was used to estimate the AVF of the sea foam layer from the measured emissivity data at frequencies 1.4, 6.8, 10.8, 35, and 36.5 GHz. Generally, the retrieved values of the AVF fall in the range of 0.85–0.98. This study implies that our method can be extended to retrieve the volume fraction of constituents of other composites media from the passive microwave remote-sensing data.

Permittivity of a sea foam layer is very important in investigating ocean brightness temperature model. At microwave frequency, the Rayleigh method is developed to estimate the effective permittivity of the sea foam layer. To simplify the tedious calculation of sea foam effective permittivity at L band (1.4 GHz), Pade’ approximation is adopted to fit the sea foam effective permittivity computed by the Rayleigh method. With this fitting formula, a new brightness temperature model of sea foam layer defined by certain geophysical parameters, such as air volume fraction (AVF), sea surface temperature (SST), sea surface salinity (SSS) and thickness of foam layer d, is given. Furthermore, the sensitivities of the brightness temperature model to SST, SSS, d and AVF of a sea foam layer at L band are discussed. The sensitivities are ranked from most to least in the order: (1) d; (2) AVF; (3) SSS; (4) SST. This result indicates that the measurement errors of d and AVF have significant impacts on the retrievals of SSS and SST. With the experimental brightness temperature data, the SSS and AFV are retrieved by cost function.

For a foam-covered sea surface, it is difficult to retrieve sea surface salinity (SSS) with L-band brightness temperature (1.4 GHz) because of the effect of a foam layer with wind speeds stronger than 7 m/s, especially at low sea surface temperature (SST). With foam-controlled experiments, emissivities of a foam-covered water surface at low SST (-1.4 degrees C to 1.7 degrees C) are measured for varying SSS, foam thickness, incidence angle, and polarization. Furthermore, a theoretical model of emissivity is introduced by combining wave approach theory with the effective medium approximation method. Good agreement is obtained upon comparing theoretical emissivities with those of experiments. The results indicate that foam parameters have a strong influence on increasing emissivity of a foam-covered water surface. Increments of experimental emissivities caused by foam thickness of 1 cm increase from about 0.014 to 0.131 for horizontal polarization and 0.022 to 0.150 for vertical polarization with SSS increase and SST decrease. Contributions of the interface between the foam layer and water surface to the foam layer emissivity increments are discussed for frequencies between 1 and 37 GHz.

This paper considers a new H2/GH2sliding mode control in controlling active suspension system subject to mismatched disturbance, without requiring a prior knowledge of disturbance. A quarter-car model is used in the study and the performance of the controller is compared with the existing passive suspension system. A simulation study is presented to prove the effectiveness and robustness of the proposed control method.

Educational robot is a platform of new educational technology. Student could study new knowledge in execution, and discover new things in exploration. It can enhance the ability of analyzing and solving problems. Orchestic robotic vehicle is designed to give the arrangement and innovation in educational robot platform. With the sensor, dance movements of each vehicle can run according to the route and coordinated motion. There is a major hardware platform which is Arduino, with ATmega328 chip of AVR microcontroller. A QTI line sensor and SHARP-GP2D12 infrared distance sensor are used in the design. Xbee wireless communication module is based on ZigBee technology which is low power network protocol of EEE802.15.4 standard. By researching and comparing several methods of control, this paper analyzes characteristics of them and the advantage and potential of development of synthetic control are testified. Choreography and coordinated control is realized for the dancing wheeled mobile robot scheme.

To investigate the effects of sea foam or whitecaps on the emissivity of sea surface, microwave radiometric experiments of foam-covered sea surface at C-band 6.8 GHz were conducted by artificial foam during September 2012 at Tangdao bay of Qingdao. The sea surface temperatures SST were from 22°C to 26.4°C, and the thickness and the air bubble size of the foam layer were controlled by a compressed air pump and monitored with a video recorder. The emissivities were obtained with the measured brightness temperatures. Furthermore, based on the experimental data, a theoretical model of sea foam emissivity is proposed by the wave approach method of two-layer medium, where the foam complex permittivity is estimated by an effective medium approximation. Experimental results show that the averaged emissivity increments of both horizontal and vertical polarizations are approximately from 0.25 to 0.35 for 1 cm of foam thickness with different SST and air volume fractions AVF. For a given thickness of the foam layer, although both AVF and SST play important roles in increasing the sea surface emissivity, the influence of AVF on the emissivity is much stronger than that of SST. The brightness temperature increases by about 113K compared to that of the foam-free surface. Moreover, the theoretical model implies that the emissivity is increased during the initial aggregation process of foam, and then fluctuates on increasing the foam thickness up to a larger saturation value. The effect of the meniscus at the foam–water boundary on foam emissivity is also discussed.

p53, which regulates cell-cycle arrest and apoptosis, is a crucial target for viruses to release cells from cell-cycle checkpoints or to protect cells from apoptosis for their own benefit. Viral evasion mechanisms of aquatic viruses remain mysterious. Here, we report the spring viremia of carp virus (SVCV) degrading and stabilizing p53 in the ubiquitin-proteasome pathway by the N and P proteins, respectively. Early in an SVCV infection, significant induction was observed in the S phase and p53 was decreased in the protein level. Further experiments demonstrated that p53 interacted with SVCV N protein and was degraded by suppressing the K63-linked ubiquitination. However, the increase of p53 was observed late in the infection and experiments suggested that p53 was bound to SVCV P protein and stabilized by enhancing the K63-linked ubiquitination. Finally, lysine residue 358 was the key site for p53 K63-linked ubiquitination by the N and P proteins. Thus, our findings suggest that fish p53 is modulated by SVCV N and P protein in two distinct mechanisms, which uncovers the strategy for the subversion of p53-mediated host innate immune responses by aquatic viruses.

This paper describes mainly about using the technology of DLL to realize merging programming , integrating the visual interface of VB and the wavelet analytical function of Matlab. Design of simulation software shows the implementation approach provides a novel idea for the application of wavelet analysis.

This paper puts forward a neural network algorithm in pile integrity test on the basis of field data and the strengths of genetic algorithm and neural network algorithm. The result proves that it has faster convergence speed than simple BP algorithm, which can avert the artificial intervention during the data handling procedure and improve the reliability of the test result.

This paper applies differential evolution (DE) algorithm to realize the output tracking control and synchronization of continuous chaotic systems. The output tracking control of single-input single-output (SISO) and multi-input multi-output (MIMO) chaotic system is investigated. Moreover, synchronization of chaotic systems with parameter mismatch or structure difference is also under discussion. Numerical simulations based on the well-known models such as Lorenz and Chen systems are used to illustrate the validity of this theoretical method.

Quasi-static compression experiments are performed on two kinds of the PTFE/Al/W reactive material specimens, fabricated by means of the cold isostatic pressing but not sintering or the pressing followed by sintering, respectively. The results show that, compared with the pressed specimens, the sintered specimens show higher failure stress and greater fracture toughness. Moreover, the mesoscale failure behaviors are significantly influenced by the sintering technique and the component ratios. There are significantly different bonding and dispersion type of the PTFE matrix between the pressed specimen and the sintered specimen, resulting in the differences of mechanical properties and failure behavior between the two kinds of specimens.

On the basis of introducing and discussing the wavelet decomposition, Principal Component Analysis and Support Vector Machine, an approach to face recognition is proposed in this paper. Firstly, wavelet decomposition is used to reduce facial image dimension. Secondly, under the premise of not increasing the number of images, Symmetric Principal Component Analysis is employed to expand the sample size. Finally, the Support Vector Machine is used for face classification and recognition. Experimental results show that, compared to traditional face recognition algorithms, the proposed approach can not only increase the recognition rate, but also can improve the efficiency of algorithms.

H.264/AVC media stream transmission is an important application in wireless network, but wireless network is an open network, the media security must be considered. The encryption approach which is used commonly for encryption of H.263/MPEG-4 stream can not be used for H.264/AVC's directly, because the H.264/AVC stream data format is different from H.263/MPEG-4. Base on residual block spatial scrambling, a format-compliant, real-time and keep-length algorithm for H.264/AVC stream encryption is proposed. In the algorithm, the residual blocks are categorized into different groups and each residual block group uses different random shuffling table. The experimental results show that H.264/AVC video stream could be encrypted in real-time while the format is kept compliant, and the length of ciphertext is as same as the plaintext. So the proposed scheme is suitable for transmitting encrypted H.264/AVC stream through wireless network and can guarantee the security of the network.

For secure stream media applications, block spatial scrambling can be used as a practice video encryption approach. The scrambling approaches commonly used for encryption of H.263/MPEG-4 stream can not be used for H.264/AVC's directly because the neighboring MacroBlocks, residual blocks and codewords of H.264/AVC stream data are context-sensitive. A novel format-compliant residual block spatial scrambling algorithm for H.264/AVC stream encryption is proposed in this article. In the algorithm, the residual blocks are categorized into different groups and each residual block group uses different random shuffling table, which is generated by the chaotic cryptosystem respectively. The experimental results show that H.264/AVC video stream could be encrypted in real-time while the format is kept compliant.

To estimate microwave emissivity of sea foam consisting of dense seawater-coated air bubbles, the effective medium approximation is applied by regarding the foam layer as an isotropic dielectric medium. The Rayleigh method is developed to calculate effective permittivity of the sea foam layer at different microwave frequencies, air volume fraction, and seawater coating thickness. With a periodic lattice model of coated bubbles and multilayered structures of effective foam media, microwave emissivities of sea foam layers with different effective permittivities obtained by the Rayleigh method are calculated. Good agreement is obtained by comparing model results with experimental data at 1.4, 10.8, and 36.5 GHz. Furthermore, sea foam microwave emissivities calculated by well-known effective permittivity formulas are investigated, such as the Silberstein, refractive model, and Maxwell-Garnett formulas. Their results are compared with those of our model. It is shown that the Rayleigh method gives more reasonable results. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JRS.7.073598]