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Background: Pulmonary arterial hypertension (PAH) is a severe and fatal clinical syndrome characterized by high blood pressure and vascular remodeling in the pulmonary arterioles, which is also a rapidly progressing disease of the lung vasculature with a poor prognosis. Although PAH medication made great advances in recent years, the efficacy and safety of the medication are unsatisfactory. Therefore, we aimed to update and expand previous studies to explore the efficacy and safety of PAH-targeted medications. Methods: Relevant articles were searched and selected from published or publicly available data in PubMed, Cochrane Library, CNKI, PsycInfo, and MEDLINE (from inception until October 1st, 2020). To assess the efficacy and safety of PAH therapies, five efficacy outcomes [6-minute walking distance (6MWD), mean pulmonary arterial pressure (mPAP), WHO functional class (WHO FC) improvement, clinical worsening, death] and two safety outcomes [adverse events (AEs), serious adverse events (SAEs)] were selected. And 6MWD was regarded as the primary efficacy outcome. Results: 50 trials included with 10 996participants were selected. In terms of efficacy, all targeted drugs were more effective than placebo. For 6MWD, Bosentan + Sildenafil, Sildenafil, Bosentan + Iloprost were better than others. Bosentan + Iloprost and Bosentan + Sildenafil were better for mPAP. Bosentan + Iloprost and Ambrisentan + Tadalafil were more effective in improving WHO FC. Bosentan + Tadalafil and Bosentan + Iloprost had the Ambrisentan probability to reduce the incidence of clinical worsening. It is demonstrated that Ambrisentan had clear benefits in reducing all-cause mortality. In terms of safety, no therapies had been shown to reduce the incidence of SAEs significantly, and Ambrisentan + Tadalafil significantly increased the incidence of AEs. Conclusions: Phosphodiesterase 5 inhibitor (PDE5i) + Endothelin Receptor Antagonists (ERA) seems to be better therapy for PAH. Prostacyclin analogs (ProsA) + ERA appear promising, though additional data is warranted. Registration PROSPERO CRD42020218818.

In this study, we consider the classical online scheduling problem with rejection on identical parallel machines. In particular, a series of independent jobs arriving online over time will be scheduled on the identical machines with the flexibility of rejection, which implies that each job is either rejected with a penalty cost or accepted and scheduled on one of the identical machines. In addition, the knowledge of each job Jj, including the processing time pj, release date rj, and penalty cost ej, is disclosed upon arrival of this job. Our goal is to minimize the total completion time of the accepted jobs plus the total penalty cost of the rejected jobs. For this problem, we provide a deterministic polynomial time online algorithm named as Delayed Shortest Processing Time with Rejection, shortly as DSPTR. For the sake of analyzing the competitive ratio of DSPTR, we introduce an interesting and efficient approach entitled as “Peeling Onion”. By means of “Peeling Onion”, we demonstrate that DSPTR is a 2-competitive online algorithm and the bound is tight. We believe that the introduction of the analysis approach “Peeling Onion” could also be applied to other online optimization problems and yield a new perspective on competitive analysis in general.

In this work, we investigate online bicriteria algorithms that consider both coverage and cost in the team formation problem, which selects a set of experts with the objective of maximizing the difference of two set functions f − l , where function f is non-negative normalized monotone approximately submodular, and function l is non-negative linear. By exploiting the problem's combinatorial structure, we present three bicriteria algorithms along with their corresponding competitive analysis. The first two algorithms handle the cases where function f is γ-weakly submodular, and strictly γ-weakly submodular, respectively. The last algorithm is more general by integrating the first two with extra parameters introduced.

This study aims to present a method for matching the stiffness and damping of a magneto-rheological (MR) air suspension system that will ensure optimal ride comfort of a road vehicle traveling on roads with different roughness and speeds. The authors study the matching of the damping coefficient with the damping ratio, and obtain the adjustment range of the damping coefficient. Based on the linearization of the air spring, a suspension model with adjustable stiffness and adjustable damping has been established. To improve the ride comfort of the vehicle and to control the dynamic deflection and dynamic load, the optimal matching of stiffness and damping under different working conditions has been analyzed by using the stepwise optimal solution method. Then, the authors design four stiffness levels and five damping levels, and propose the parameter matching scheme of the MR air suspension system. The theoretical analysis shows that the proposed scheme can improve vehicle vertical dynamic performance. Four levels of adjustment for the width of the orifice between the air spring and auxiliary chamber and six levels of adjustment for the MR damper have been designed respectively. The findings of this study will inform other studies on vibration control.

Light field (LF) imaging enables new possibilities for digital imaging, such as digital refocusing, changing of focus plane, changing of viewpoint, scene-depth estimation, and 3D scene reconstruction, by capturing both spatial and angular information of light rays. However, one main problem in dealing with LF data is its sheer volume. In this context, efficient compression methods are needed for such a particular type of content. In this paper, we propose a content-based LF image-compression method with Gaussian process regression to improve the compression efficiency and accelerate the prediction procedure. First, the LF image is fed to the intra-frame codec of HEVC. In the prediction procedure, the prediction units (PUs) are classified as non-homogenous texture units, homogenous texture units, and visually flat units, based on the content property of the LF image. For each category, we design a corresponding Gaussian process regression (GPR)-based prediction method. Moreover, we propose a classification mechanism to exactly decide to which category the current PU belongs, so as to adjust the trade-off between the computational burden and the LF image coding efficiency. Experimental results demonstrate that the proposed LF image compression method is superior to several other state-of-the-art compression methods in terms of different quality metrics. Furthermore, the proposed method can also achieve a good visual quality of views rendered from decoded LF contents.

Graphitic carbon nitride (g-C3N4), with a moderate band gap (∼2.7 eV), high chemical and thermal stability, has been the hotspot in environmental photocatalysis. However, its performance is still u...

We consider an online stochastic unrelated machines scheduling problem. Specifically, a set of jobs arriving online over time must be randomly scheduled on the unrelated machines, which implies that the information of each job, including the release date and the weight, is not known until it is released. Furthermore, the actual processing time of each job is disclosed upon completion of this job. In addition, we focus on unrelated machines, which means that each job has a processing speed on every machine. Our goal is to minimize the expected total weighted completion time of all jobs. In this paper, we present a randomized selection algorithm for this problem and prove that the competitive ratio is a constant. Moreover, we show that it is asymptotic optimal for the online stochastic uniform machines scheduling problem when some parameters are bounded. Moreover, our proof does not require any probabilistic assumption on the job parameters.

Nanolayered CrAlN/CNx multilayer films (MFs) with varying modulation periods (thickness of the CNx layer: LCNx) were deposited by ion beam assisted magnetron sputtering. The morphologies and microstructures of these films were investigated. Results indicated that the CNx layer in the CrAlN/CNx-MFs transferred from an amorphous structure into polycrystalline body-centered cubic C3N4 when its thickness was less than 1.6 nm. The corrosion behavior of these CrAlN/CNx-MFs was investigated by polarization test and electrochemical impedance spectroscopy in a 3.5 wt% NaCl aqueous solution. Results showed that the multilayer structure could effectively increase the corrosion resistance of the alloy in the NaCl solution. The thick CrAlN layer accelerated the growth of perforative columnar defects as LCNx increased, which destroyed the compact structure, accelerated the infiltration of corrosive medium, and increased the probability of pitting corrosion. The CrAlN/CNx-MFs had a 1.6 nm thickness of laminated CNx, and their corrosion resistance was higher than those of the single layer CrAlN and single layer CNx because of the lack of surface cracks and pores.

Organic pollutants’ treatment in wastewater has attracted extensive attention due to its degradation-resistance and potentially hazardous to human health. Some organic matters such as persistent organic pollutants (POPs) could exist in environment and resist to decomposition, which may cause chronic intoxication or even cancers. Because photocatalytic technique is efficient, nontoxic, and cost-effective to degrade organic pollutants, some semiconductors including TiO2 and ZnO as photocatalysts have aroused wide public concern. CeO2 has been reported as an efficient photocatalyst in contrast to TiO2 owing to its high oxygen storage, eco-friendly properties and photostability. But inefficient utilization of solar energy due to its intrinsic wide bandgap restrains its further application in real environmental pollutant treatment. In order to improve photocatalytic performances of CeO2, some modifications have been developed such as doping ions, coupling with semiconductor and construction of CeO2-based solid-solution. The purpose of this review is to introduce these techniques, reveals its fundamental mechanisms and the recent researches about photodegradation of organic pollutants in wastewater over CeO2-based photocatalysts. Besides, this review will evaluate the photocatalytic performance for organic pollutants and outlook the challenges and prospects in the future.

Graphitic carbon nitride (g-C3N4), a conjugated polymer semiconductor, has drawn increasing attention in environmental photocatalysis over the past decade, owing to its highly chemical stability, low cost and suitable electronic structure with a mild energy gap (∼ 2.7 eV). Whereas, its practical applications in wastewater purification are still faced with huge challenges, such as insufficient visible light absorption, low electronic conductivity, poor surface area and fast recombination of photoinduced charge carriers. The modification of g-C3N4 by coupling with other nanomaterials or forming unique nanostructures have been confirmed as valuable strategies. In this review, we give a comprehensive introduction about the recent developments in engineering g-C3N4 by constructing heterostructures or diverse morphologies to improve its photodegradation performance for the photocatalytic degradation of persistent organic pollutants. Such heterojunctions contain metal/g-C3N4, g-C3N4/C-based material and many other binary or ternary composites, and these special morphologies normally include nanorods, nanowires, nanotubes, nanosheets, porous architectures and other different tunable nanostructures. Several enhanced photocatalytic mechanisms for these nanohybrids under visible light irradiation have been explicated in detail, and future perspectives are also concluded in this review.

Despite some efforts have been made in the research of supramolecular hyperbranched polymers (SHPs) self-assemblies, the study which has not been consideration to date is the influence of incoming stimuli-responsive polymer chain on their self-assembly property undergo outer stimuli. The introduction of stimuli-responsive segments which could maintain their hydrophilic property are expected to affect the self-assembly behaviour of SHPs and expand their further biomedical application. In this paper, AB2-type macromolecular monomer, LA-(CD-PDMA)2, which consisted one lithocholic acid (LA) and two β-cyclodextrin terminated poly(2-(dimethylamino)ethyl methacrylate) segments (CD-PDMA) was synthesized. LA-(CD-PDMA)2 based SHP were obtained based on the host-guest inclusion interactions of CD/LA moietes and with PDMA as pH-responsive hydrophilic chains. As a control to study the influence of incoming PDMA chains, both LA-(CD-PDMA)2 based SHPs-1 and LA-CD2 based SHPs-2 self-assemblies were comparatively investiged through 2D 1H NMR ROESY, transmission electron microscopy (TEM) and dynamic light scattering (DLS). The results suggested that except for the higher drug loading efficiency LA-(CD-PDMA)2 based SHPs-1 pocessing, the release rates of SHPs-1 increased notably at pH 5.0 than that of pH 7.4 due to the repulsion and stretch of protonated PDMA chains while the release rates of SHPs-2 showed no obvious difference. Finally, basic cell experiments demonstrated that the SHPs based self-assemblies can be internalized into cancer cells, indicating their potential application in the drug delivery field.

This paper investigates the inter-connectedness between WTI oil price returns and the returns of listed firms in the US energy sector. Specifically, we focus on the issue of whether firm-level idiosyncratic information matters. A generalised dynamic factor model is used to separate common components from idiosyncratic components in these energy stocks. Systemic connectedness is then estimated following Diebold and Yilmaz (2014). Our empirical results demonstrate the important role of industrial-level common information in understanding the oil–stock relationship. A number of interesting points include: the US energy sector is the net contributor to WTI price changes, but the effect is mainly driven by industrial-level common information; the oil and gas industry dominates other industries in the energy sector; the dynamic analysis shows that although idiosyncratic information is mostly independent of oil shocks, individual energy stock returns do respond to WTI price movements.

Photodegradation has been considered as an efficient environmental remediation technology to eliminate organic pollutants from wastewater, and the calling for high-performance photocatalysts is end...

Designing and fabricating environmental friendly adsorbents with more accessible active sites and higher specific surface area for achieving rapid kinetics and high efficiency have become an impending challenge in radionuclides’ pollution remediation. To overcome these issues, we rationally designed the hierarchical structured layered double hydroxides with mesoporous carbon template (CMK-3@LDHs) by in situ hydrothermal method. The adsorption data could be well simulated with pseudo-second-order and Langmuir model, and the results indicated that the CMK-3@LDHs exhibited higher adsorption capacities (171 mg·g−1 for CMK-3@Mg-Al LDHs and 301 mg·g−1 for CMK-3@Ni-Al LDHs at pH = 5.0) and more rapid kinetics (achieved equilibrium within 30 min) than SBA-15@LDHs towards U(VI). The kinetic model simulation demonstrated that the adsorption rate was dominated by intra-particle and film diffusion models simultaneously. In addition, the interaction between U(VI) and LDHs was pH-dependent and weakly related with ionic strength at pH

This paper studies online scheduling of jobs with kind release times on a single machine. Here “kind release time” means that in online setting, no jobs can be released when the machine is busy. Each job J has a kind release time r(J) ≥ 0, a processing time p(J) > 0 and a deadline d(J) > 0. The goal is to determine a schedule which maximizes total processing time (Σp(J)E(J)) or total number (ΣE(J)) of the accepted jobs. For the first objective function Σp(J)E(J), we first present a lower bound \(\sqrt 2 \), and then provide an online algorithm LEJ with a competitive ratio of 3. This is the first deterministic algorithm for the problem with a constant competitive ratio. When p(J) ∈ {1, k}, k > 1 is a real number, we first present a lower bound min{(1+k)/k, 2k/(1+k)}, and then we show that LEJ has a competitive ratio of 1+⌈k⌉/k. In particular, when all the k length jobs have tight deadlines, we first present a lower bound max{4/(2 + k), 1} (for Σp(J)E(J)) and 4/3 (for ΣE(J)). Then we prove that LEJ is ⌈k⌉/k-competitive for Σp(J)E(J) and we provide an online algorithm H with a competitive ratio of 2⌈k⌉/(⌈k⌉ + 1) for the second objective function ΣE(J).

The electrochemical formation mechanism of microdroplets formed around a primary droplet of 3.5% NaCl solution on an iron-plated film was investigated by quartz crystal microbalance (QCM) and concentric three-electrode array (CTEA) measurements. During the initial stage, the microdroplets mainly originate from evaporation owing to cathodic polarization and electric current of the localized corrosion cell under the primary droplet. The maximal electrochemical potential difference between the anode and cathode was measured to be 0.36 V and acted as the driving force for the formation of microdroplets. The maximums of anodic and cathodic electric current density of pure iron under the NaCl droplet are 764 and −152 μA/cm2, respectively. Propagation of microdroplets in the developing stage attributes to horizontal movement of the electrolyte, water evaporation, and recondensation from primary and capillary condensation from moist air. The results of the study suggest that the initiation and propagation of microdroplets could promote and accelerate marine atmospheric corrosion.

The selection of time constant is the key to suppress the fluctuation of wind power output by using the first-order filter. This paper analyzes the relationship between the filtering time constant and the fluctuation smoothing quantity in different time scales according to the wind power fluctuation smoothing index. And proposes a strategy of putting two time-constant filters in series to suppress the fluctuation of wind power on two time scales. Setting the wind power fluctuation threshold of energy storage switching and adjusting the time constant near the threshold smoothly to reduce the impact of energy storage switching on the wind/storage system output fluctuation. Finally, the wind power data measured in a wind field is taken as an example to conduct simulation analysis through MATLAB/Simulink, which shows that the proposed strategy can meet the requirements of wind power index and reduce the energy storage grid operation time and charge and discharge times.

© 2020, Springer Science+Business Media, LLC, part of Springer Nature. Packet loss and error propagation induced by it are significant causes of visual impairments in video applications. Most of the existing video quality assessment models are developed at frame or sequence level, which can not accurately describe the impact of packet loss on the local regions in one frame. In this paper, we propose an error sensitivity model to evaluate the impact of a single packet loss. We also make full use of the spatio-temporal correlation of the video and analyze a set of features that directly impact the perceptual quality of videos, based on the specific situation of video packet loss. With the aid of the support vector regression (SVR), these features are used to predict the error sensitivity of the local region. The proposed model is tested on six video sequences. Experimental results show that the proposed model predicts sensitivity of videos to different packet loss cases with certain reasonable accuracy, and provides good generalization ability, which turns out outperform the state-of-art image and video quality assessment methods.

Halohydrin dehalogenases are usually recognized as strict β-position regioselective enzymes in the nucleophile-mediated ring-opening of epoxides. Here we found the HheG from Ilumatobacter coccineus exhibited excellent α-position regioselectivity in the azide-mediated ring-opening of styrene oxide derivatives 1a–1k, producing the corresponding 2-azido-2-aryl-1-ols 2a–2k with the yields up to 96%.

High-speed camera technology are used in experimental studies for flame propagation of the local dust cloud of low density polyethylene (LDPE) in a semi-open duct, to examine the impacts of dust cloud concentration and particle size on flame propagation. This proves that the dust cloud concentration exerts significant impact on flame propagation. Both the maximum and average flame speeds follow a general trend of increasing at first and then decreasing with concentration. The continuous acceleration distance of the flame increases at first but then levels off with the concentration. The flame developing processes between the fuel-lean and fuel-rich states are completely opposite. The particle size also exerts significant impact on the flame speed and shape. The smaller the particle size and the larger the specific surface area, the larger the total reaction area and the combustion rate, the longer the continuous acceleration distance of the flame, the higher the maximum and average flame speeds, the clearer the flame contour, and the smoother and brighter the front surface. The flame of a larger particle size is likely to segment in the second half of propagation, and the front surface is easily narrowed along the radial direction of the duct. Moreover, the flame propagates far beyond the original dust cloud range in a manner proportional to dust cloud concentration and inversely proportional to particle size. These conclusions can be used as a scientific reference for explosion hazard analysis and process safety design of LDPE powders.

In this work, structure-deficient mesoporous g-C3N4 (DMCN) was fabricated via a facile hard template approach with water-bath aging pretreatment. The in situ introduced cyano groups (–CN) and hydroxyl groups (–OH) effectively modulated the energy levels, improved visible light absorption, and meanwhile served as strong electron-withdrawing groups, promoting the efficient separation and transfer of photogenerated charge carriers. With the addition of persulfate (PS) as an oxidant, DMCN exhibited superior catalytic activity and stability for bisphenol A (BPA) degradation. 100% BPA could be degraded for optimal DMCN-3.5 with 0.5 g L−1 catalyst and 1.0 g L−1 PS under visible light (420 nm ≤ λ ≤ 780 nm) within 15 min, whose reaction rate (0.317 min−1) was ∼39.6 times higher than that of bulk g-C3N4 (0.008 min−1). Based on EPR and quenching tests, h+ and SO4˙− radicals were determined as major oxidizing species in the DMCN/PS/Vis system. The enhanced catalytic performance was mainly attributed to PS serving as the electron acceptor and transfer of photogenerated e− to PS via –CN and C–OH groups, resulting in the efficient activation of PS for SO4˙− and a high light quantum efficiency. This work gives novel insights into in situ defect engineering for g-C3N4 and offers a new chance for visible-light-induced sulfate radical-based Fenton-like system to govern contaminated water.

Nowadays, more and more researchers pay close attention to the decontamination of radioactive uranium because of its high toxicity and long half-life in the environment. Although many strategies fo...

Titanium alloy Ti-6242 (Ti-6Al-2Sn-4Zr-2Mo) is frequently used in the high-pressure compressor of aero engines. While exhibiting high strength at elevated temperatures, it is susceptible to dwell fatigue at temperatures below ∼473 K due in part to the presence of microtextured regions (MTRs), also known as macrozones. This work investigates the role of forging direction on the mesoscale mechanical response of MTRs. The crystal plasticity finite element (CPFE) method was used to simulate large strain compression of MTRs with different initial crystallographic and morphological orientation with respect to the axial direction of the extruded billet. These simulations included cases where the c-axis of neighboring MTRs were (i) both perpendicular, (ii) one at 45° and one perpendicular, and (iii) one parallel and one perpendicular, to the compression direction. The effectiveness of each processing direction on the breakdown of MTRs is inferred through the extent of lattice rotation and the development of internal misorientations within the MTRs. The calculations reveal that case (i) leads to the most effective MTR breakdown but the c-axis remains similarly aligned; the c-axis is more scattered in case (iii) but the extent is limited by the high critical resolved shear stress of the pyramidal slip systems. Under uniaxial compression, competitive slip system activity correlates with positive divergence of reorientation velocity field in Rodrigues’ space as well as efficient breakdown of MTR.

The hierarchical core-shell and yolk-shell magnetic titanate nanosheets (Fe3O4@TNS) were successfully synthesized by employing magnetic nanoparticles (NPs) as interior core and intercrossed titanate nanostructures (NSs) as exterior shell. The as-prepared magnetic Fe3O4@TNS nanosheets had high specific areas (114.9 m2 g−1 for core-shell Fe3O4@TNS and 130.1 m2 g−1 for yolk-shell Fe3O4@TNS). Taking advantage of the unique multilayer structure, the nanosheets were suitable for eliminating U(VI) from polluted water environment. The sorption was strongly affected by pH values and weakly influenced by ionic strength, suggesting that the sorption of U(VI) on Fe3O4@TNS was mainly dominated by ion exchange and outer-sphere surface complexion. The maximum sorption capacities (Qmax) calculated from the Langmuir model were 68.59, 121.36 and 264.55 mg g−1 for core-shell Fe3O4@TNS and 82.85, 173.01 and 283.29 mg g−1 for yolk-shell Fe3O4@TNS, at 298 K, 313 K and 328 K, respectively. Thermodynamic parameters (ΔH0, ΔS0 and ΔG0) demonstrated that the sorption process was endothermic and spontaneous. Based on X-ray photoelectron spectroscopy (XPS) analyses, the sorption mechanism was confirmed to be cation-exchange between interlayered Na+ and UO22+. The yolk-shell Fe3O4@TNS had more extraordinary sorption efficiency than core-shell Fe3O4@TNS since the yolk-shell structure provided internal void space inside the titanate shell to accommodate more exchangeable active sites. The flexible recollection and high efficient sorption capacity made core-shell and yolk-shell Fe3O4@TNS nanosheets promising materials to eliminate U(VI) or other actinides in wastewater cleanup applications.

Light field imaging can capture both spatial and angular information of a 3D scene and is considered as a prospective acquisition and display solution to supply a more natural and fatigue-free 3D visualization. However, one problem that occupies an important position to deal with the light field data is the sheer size of data volume. In this context, efficient coding schemes for this particular type of image are needed. In this paper, we propose a hybrid linear weighted prediction and intra block copy based light field image codec architecture based on high efficiency video coding screen content coding extensions (HEVC SCC) standard to effectively compress the light field image data. In order to improve the prediction accuracy, a linear weighted prediction method is integrated into HEVC SCC standard, where a locally correction weighted based method is used to derive the weight coefficient vector. However, for the non-homogenous texture area, a best match in linear weighted prediction method does not necessarily lead to a good prediction of the coding block. In order to alleviate such shortcoming, the proposed hybrid codec architecture explores the idea of using the intra block copy scheme to find the best prediction of the coding block based on rate-distortion optimization. For the reason that the used “try all then select best” intra mode decision method is time-consuming, we further propose a fast mode decision scheme for the hybrid codec architecture to reduce the computation complexity. Experimental results demonstrate the advantage of the proposed hybrid codec architecture in terms of different quality metrics as well as the visual quality of views rendered from decompressed light field content, compared to the HEVC intra-prediction method and several other prediction methods in this field.

Fire exposure causes significant mechanical property degradation of metallic materials. This paper investigates the influence of fire exposure on mechanical response of AA5083 through in situ neutron diffraction tensile tests and crystal plasticity finite element simulations. The Mechanical Threshold Stress (MTS) model is utilized, with a focus on the lattice strain response under tensile loading before and after exposure. A rigorous material parameter calibration procedure is proposed for this MTS model directly based on yield stress, plastic flow, hardening and rate dependency as a function of temperature, requiring only the macroscopic stress–strain curve. Material parameters of virgin material and fire-exposed material with full recrystallization are calibrated separately using this procedure. To initiate the investigation of mechanical degradation caused by fire exposure, a fire-exposed specimen with partial recrystallization is simulated by assigning material parameters and texture of recrystallized grains to selected grains in the virgin material according to the recrystallization fraction. Experimentally measured stress–strain curves and lattice strain evolution are employed to validate the simulations. For the first time, the local mechanical response of AA5083 is compared between in situ testing and finite element simulations, and the discrepancies of lattice strain evolution between virgin and fire-exposed material are discussed. Finally, the influence of fire-exposure on stress and lattice strain distribution is investigated to provide insight into mechanical property degradation.

Massive recent investigations from both industry and academia have been poured into autostereoscopic display. One of the emerging techniques, light field image (LFI), can provide more immersive perception by increasing the number of views and the spatial resolution. However, these advantages restrict the storage and transmission due to such dense-view image simultaneously. To solve this problem, we propose to compress the LFI using multiview video plus depth (MVD) coding architecture. In this paper, we preliminarily estimate the depth based on the concept of epipolar plane image. To achieve a depth value, we design an optimal slope decision algorithm to determine the best slope with the minimal cost. While this rough estimation produces some error points within initial depth map, therefore, we present a depth optimization algorithm using the characteristic of the associated texture image. Ultimately, a small number of selected viewpoint images are encoded with their corresponding depth maps using the MVD framework, and then, the unselected viewpoint images are synthesized by depth image-based rendering technique. To verify the validity of the proposed LFI compression scheme, extensive experiments are conducted. The simulated results demonstrate that the proposed depth map estimation algorithm is superior to other state-of-the-art methods for the LFI. Meanwhile, our LFI compression method outperforms other LFI compression algorithms significantly.

Virtual reality (VR) can provide users an immersive and realistic visual experience, which leads to the widely use of VR in many fields. However, transmission of the ultrahigh resolution omnidirectional video requires huge bandwidth, which brings great challenges for real-time VR application. In this paper, we propose a scalable omnidirectional video coding method to improve the coding efficiency with the help of the viewer's point of view (POV) and provide three-layer scalability as well. Based on the equirectangular projection (ERP), a down-sampling procedure of ERP video with corresponding super-resolution method is proposed to save bandwidth and provide spatial resolution scalability. With the super-resolution version of the reconstructed down-sampled video as the inter-view reference, the viewer's POV within sphere is mapped and encoded in high quality, while the non POV areas are compressed in low quality to further improve the coding efficiency and provide quality scalability. The correlation of the ERP and cube map projection is utilized in the POV mapping procedure. The proposed scalable coding method is achieved based on the multiview extension of high efficiency video coding, where only a few modifications are operated in the encoder side. Experiments results demonstrate that the proposed method can save approximately 75% average bit rate with no significant decrease in quality of the viewer's POV region compared with HEVC standard.

We revisit the classical online scheduling problem on parallel machines for minimizing total weighted completion time. In the problem, a set of independent jobs arriving online over time has to be scheduled on identical machines, where the information of each job including its processing time and weight is not known in advance. The goal is to minimize the total weighted completion time of the jobs. For this problem, we propose an improved 2.11-competitive online algorithm based on a kind of waiting strategy.

Development of a more cost-effective radiation source for use in plant-growing facilities would be of significant benefit for commercial crop production applications. A series of co-doped B3+ and Na+ ions Sr4Al14O25:Mn4+ inorganic luminescence materials which can be used for plant growth were successfully synthesized through a conventional high-temperature solid-state reaction. Powder X-ray diffraction was used to confirm the crystal structure and phase purity of the obtained samples. Then scanning electron microscopy elemental mapping was undertaken to characterize the distribution of the doped ions. Detail investigations on the photoluminescence emission and excitation spectra revealed that emission intensity of tetravalent manganese ions can be well enhanced by monovalent sodium ions and trivalent boron ions under near-ultraviolet and blue excitation. Additionally, crystal field parameters and energies of states are calculated and discussed in detail. Particularly we achieve a photoluminescence internal quantum yield as high as 60.8% under 450 nm blue light excitation for Sr4Al14O25:Mn4+, Na+, B3+. Therefore, satisfactory luminescence properties make these phosphors available to LEDs for plant growth.

A new fluorescent probe (MBT) for the detection of 4-methylbenzenethiol (p-MePhSH) was developed by using 4-(benzo[d]thiazol-2-yl)-3-methoxyphenol as the fluorophore and 2,4-dinitrophenyl ether as the sensing moiety. Probe MBT displayed good selectivity toward p-MePhSH in DMSO/PBS buffer (5/5, v/v) solution and anti-interference over other competitive species via nucleophilic aromatic substitution. The fluorescence intensities of the probe responded p-MePhSH showed a 22-fold enhancement and good linearity with p-MePhSH concentration collected in the range of 0–15 μM. Moreover, the probe is sensitive to p-MePhSH and the limit of detection is 45 nM. The sensing mechanism of probe MBT was verified by high-resolution mass spectrometry and fluorescence lifetime. Furthermore, the probe was used to the detection of p-MePhSH in real water samples.

Two series of phosphors of Ca8MgSc(PO4)7:Dy3+ and Sr8MgSc(PO4)7:Dy3+ single-phase white-emitting phosphors with high thermal emission stability are synthesized by the high-temperature solid-state reaction. The crystal structure, photoluminescence (PL), PL excitation (PLE), and thermal PL quenching spectra of Ca8MgSc(PO4)7:xDy3+ and Sr8MgSc(PO4)7:xDy3+ were investigated and compared in detail. Upon excitation at 387 nm, M8MgSc(PO4)7:xDy3+ (M = Ca/Sr) showed white emission centered at 480, 571, 660, and 754 nm. The white-emitting Dy-phosphor Ca8MgSc(PO4)7:Dy3+ (CMSP:Dy) had good terminal stability. The emission intensity of Ca8MgSc(PO4)7:Dy3+ still remained 95.2% of that at room temperature at 160 °C, and remained 77.3% at 300 °C under 387 nm excitation.

We report the CW laser operation and wavelength tunability of 10 at%, 15 at% and 20 at% Yb 3+ -doping LuAG ceramics pumped at 970 nm. The absorption saturation effects were taken into account herein. For 10 at% Yb 3+ -doping sample, the maximum slop efficiency and output power was 60.7% and 1.8 W, respectively. Furthermore, the slop efficiencies of 52.3% (15 at%) and 46.5% (20 at%) were reported. What's more, the maximum optical-to-optical efficiency for our samples was determined to be 40.1%, 36.8%, and 33.1% at the incident pump power of 4 W, respectively. The round-trip cavity loss of the laser system based on our Yb 3+ :LuAG ceramics were evaluated. The tuning curve of a 20 at% Yb 3+ :LuAG ceramic extended from 1018 nm up to 1062 nm, and that of 10 at% and 15 at% samples became much more broader, making Yb 3+ :LuAG ceramics possible candidates for ultrashort pulse generation.

Nowadays, major commercial w-LEDs fabricated by the traditionally gold-wire-welding packaging technology have undergone considerable development as indoor/outdoor lighting sources due to its high-energy utilization efficiency, long service life, environmental friendliness, and excellent chromatic stability. While, new generation applications in projections, automotive lighting, street lighting, plaza lighting, and high-end general lighting need further improvements in power handling and light extraction. Herein, transparent Ce:YAG glass-ceramics (GCs) phosphor was prepared by low-temperature co-sintering polycrystalline Ce:YAG phosphor powder and home-made PbO-B2O3-ZnO-SiO2 glass powder. Thereafter, the flip-chip (FC) w-LEDs were fabricated with the GCs phosphor plates and FC blue chips. The GCs-based FC w-LEDs show not only excellent heat- and humidity-resistance characteristics, but also superior optical performances with an LE of 112.8 lm/W, a CRI of 71.2, a CCT of 6103 K as well as a chromaticity coordinate of (0.3202, 0.3298), under a high operation current of 400 mA. The technology route will open a practically commercial feasible approach to achieve excellent performances for advanced high-power FC w-LEDs.

In this paper, the degradation of mechanical properties of marine structural aluminum alloy AA5083 and onset of lattice plastic anisotropy subsequent to fire exposure is investigated. For virgin and fire-exposed samples, microstructural characterization is carried out for the first time and changes in lattice specific strain responses under step and continuous axial deformation are studied using novel bulk neutron diffraction. Peak fitting of raw data yields d-spacing values of reflections of interest and allows for lattice specific strain calculations. A reduction in yield stress from 260 MPa in the virgin material to 120 MPa in the fire-exposed sample is observed. Virgin material exhibits dynamic strain aging during plastic deformation; this is captured in neutron diffraction measurements. Larger peak broadening for virgin material indicates possible presence of Type II and III residual stresses due to intergranular stress or dislocation stress fields. Stress vs. lattice strain plots show large deviations from linearity post-yield for fire-exposed samples. This is due to strain redistribution among grains as well as grain reorientation. After fire exposure dynamic strain aging does not occur, but individual lattice planes reveal plastic anisotropy in their response to plastic deformation. Results from neutron diffraction, combined with electron backscatter diffraction characterization, provide insight into the yielding mechanisms of AA5083 and effects of fire exposure.

In order to understand the onset of Rayleigh-Benard convection of cold water near its density maximum in a vertical annular container heated from below and cooled from above, the instability of the static diffusive state was investigated by linear stability analysis. Two kinds of thermal boundary conditions, perfect insulating and conducting sidewalls, were used. The aspect ratio and radius ratio of the annular container varied from 0.5 to 4.5 and 0.1 to 0.8, respectively. Results indicate that the critical Rayleigh number and the critical wave number increase with the increase of density inversion parameter. There are some new flow modes with large azimuthal wave number near the convection onset for cold water with density maximum, which are not observed in Rayleigh-Benard convection of the Boussinesq fluids. The stratified flow phenomenon in cold water with density maximum is certified. The larger the density inversion parameter is, the more obvious the stratified flow phenomenon becomes. With the increase of the aspect ratio, the critical Rayleigh number decreases, but the critical wave number increases. However, with the increase of the radius ratio, both the critical Rayleigh number and the critical wave number increase continuously. Furthermore, the effect of thermal boundary conditions at the sidewalls on the convection stability is also validated.

Industrial control systems (ICSs) are widely used in critical infrastructures, making them popular targets for attacks to cause catastrophic physical damage. As one of the most critical components in ICSs, the programmable logic controller (PLC) controls the actuators directly. A PLC executing a malicious program can cause significant property loss or even casualties. The number of attacks targeted at PLCs has increased noticeably over the last few years, exposing the vulnerability of the PLC and the importance of PLC protection. Unfortunately, PLCs cannot be protected by traditional intrusion detection systems or antivirus software. Thus, an effective method for PLC protection is yet to be designed. Motivated by these concerns, we propose a non-invasive powerbased anomaly detection scheme for PLCs. The basic idea is to detect malicious software execution in a PLC through analyzing its power consumption, which is measured by inserting a shunt resistor in series with the CPU in a PLC while it is executing instructions. To analyze the power measurements, we extract a discriminative feature set from the power trace, and then train a long short-term memory (LSTM) neural network with the features of normal samples to predict the next time step of a normal sample. Finally, an abnormal sample is identified through comparing the predicted sample and the actual sample. The advantages of our method are that it requires no software modification on the original system and is able to detect unknown attacks effectively. The method is evaluated on a lab testbed, and for a trojan attack whose difference from the normal program is around 0.63%, the detection accuracy reaches 99.83%.

A novel red-emitting Lu3Al5O12:Mn4+ (LuAG:Mn4+) phosphor was synthesized by a solid-state reaction. The emission-band position is shifted to red region by gradually increasing the amount of substitution of Lu3+ for Y3+, eventually yielding fully Y3Al5O12:Mn4+ (YAG:Mn4+). The compared structural and optical properties of the phosphors were investigated. From the experimentally measured spectroscopic data, crystal field parameter Dq and Racah parameters B and C are calculated to be 2127, 1464, and 3620 cm–1 in LuAG:Mn4+, respectively. In YAG:Mn4+, Dq, B, and C are calculated to be 2082, 1524, and 3740 cm–1, respectively. Impressively, Ca2+/Li+/Mg2+/Sr2+/Sc3+/Na+ dopants were found to be beneficial for enhancing Mn4+ luminescence, and the related mechanisms were systematically discussed.

Two-stage submodular maximization problems have been recently applied in machine learning, economics and engineering. In this paper, we consider a two-stage submodular problem subject to cardinality constraint and matroid constraint. Previous work for this problem usually assume that the objective functions are non-negative and monotone. Our focus in this work relaxes these assumptions by considering an objective function which is the expected difference of a non-negative monotone submodular function and a non-negative monotone modular function, and hence neither non-negative nor monotone. We present strong approximation guarantees by offering two bi-factor approximation algorithms for this problem. The first is a deterministic \(\left( \frac{1}{2}\left( 1-e^{-2}\right) , 1\right) \)-approximation algorithm, and the second is a randomized \(\left( \frac{1}{2}\left( 1-e^{-2}\right) -\epsilon , 1\right) \)-approximation algorithm with improved time efficiency. Moreover, we generalize the matroid constraint to k-matroid constraint and also give the corresponding approximation algorithms.

Carbon-and diamond-like-carbon coated Ti alloys hold great promise for tissue engineering applications. Unfortunately, their strong intrinsic stress leads to the adhesion failure of the films. Herein, a series of a-C films with different Ca content were prepared on Ti6Al4V via co-sputtering deposition technology. Homogeneous spherical Ca nanoclusters, with an inner diameter of 2-6 nm, were formed in an amorphous carbon matrix. The addition of Ca induced indistinctive variation in either phase composition or topography. However, the introduction of Ca not only improved the mechanical properties of a-C film but also significantly strengthened its adhesion to osteoblasts. The bio-tribological properties of Ca/a-C films were also assessed using a tribometer in FBS solution. The Ca/a-C films exhibited a low friction coefficient of 0.083 and a low wear rate of 1.02-1.24×10-6 mm3/Nm. The low coefficient of friction (COF) of the Ca/a-C films indicates their superior mechanical properties, making them the promising target of nanocomposite films used in bio-tribological applications. Well-stretched cells and the developed actin filaments were distinctly observed on the Ca/a-C films in the osteoblast cell adhesion experiments. In addition, the Ca/a-C films promoted cell proliferation and showed high cell viability. After being implanted for 4 weeks, the Ca/a-C implant material still adhered well to the muscle tissue, without inducing hyperergic or inflammatory reactions. Collectively, our results suggest that the Ca/a-C film is an ideal mounting material for bone tissue engineering.

The 18O/16O of lignin at bulk, molecular and positional levels can be used to extract valuable information about climate, plant growth environment, plant physiology, and plant metabolism. Access to the individual oxygen isotope compositions (δ18O) in the lignin monomeric units is, however, challenging as depolymerization of lignin to release the monomeric units may cause isotope fractionation. We have developed a novel method to measure the δ18O of the three oxygens (O-3, O-4 and O-5) attached to the aromatic ring of the monomeric units (bearing no oxygen in their side chains) releasable by highly selective W2C/AC (tungsten carbide supported by activated carbon)-catalyzed hydrogenolysis of lignin. O-4 is obtained by measuring the δ18O of H-type monomeric unit, while O-3 and O-5 can be calculated following isotope mass balance between H, G and S-type monomeric units measurable simultaneously with GC/Py/IRMS (gas chromatography-pyrolysis-isotope ratio mass spectrometry). The measurement precisions are better than 1.15 mUr and 4.15 mUr at molecular and positional levels, respectively. It was shown that there were a δ18OH > δ18OG > δ18OS isotopic order in the herbaceous plant lignin and an (inclusive) opposite order in woody plant lignin. Such differences in isotopic order is likely to be caused by the fact that both L-tyrosine, which carries an 18O-enriched leaf water signal, and L-phenylalanine, which carries mainly a molecular O2 isotopic signal, serve as the precursors for lignin biosynthesis in herbaceous plants while only the latter serves as precursor for lignin biosynthesis in woody plants. We have highlighted the potential application of such molecular and positional levels isotopic signals in plant physiological, metabolic, lignin biosynthetic and climate studies.

In the absence of an intermediate layer, ODS-W (W–2%Y2O3) and copper (Cu) powders were successfully combined by spark plasma sintering (SPS) in the temperature range of 850 °C-980 °C. In this paper, the microstructure of the joints at different temperatures was investigated by SEM, EDS, and TEM, and the phase composition of the bonded joints was studied by XRD. The effects of sintering temperature on diffusion distance and physical mechanical properties were analyzed. The diffusion distances of Cu and W increased as the bonding temperature increased. At 980 °C, no microcracks and pores were formed at the joint of ODS-W/Cu, and the mutual diffusion distance between W and Cu was the longest, reaching 1.3 μm. When yttrium oxide started to emerge near the ODS-W/Cu joint, the diffusion distance between W and Cu increased. In addition, at 980 °C, the ODS-W/Cu connector has a great difference compared with other temperatures, with the tensile strength up to 312 MPa and hardness up to 200 H V.

Explosion flame propagation characteristics and overpressure distribution of low density polyethylene (LDPE) dust and ethylene hybrid mixture were investigated under N2 inerting conditions using a custom-designed 12 L cylindrical explosion tank. The results showed that a small amount of ethylene could promote the explosion characteristics of LDPE dust. N2 inerting had different inhibitory effects on the explosion flame of LDPE dust and its mixture with ethylene. The explosion overpressure strength of the LDPE dust/ethylene hybrid mixture decreased with increasing N2 concentration. The overall suppression effect of N2 on the explosion overpressure of the LDPE dust was better than that of the LDPE dust/ethylene hybrid mixture explosion. As the ethylene concentration increased from 0% to 2.5%, the limiting oxygen concentration decreased by 13% oxygen. This small amount of ethylene restricted the traditional inerting process. The study conclusions can provide further scientific basis for the inerting and explosion proofing design of production process equipment involving LDPE dust.

The explosion characteristic parameters of polyethylene dust were systematically investigated. The variations in the maximum explosion pressure (Pmax), explosion index (Kst), minimum ignition energy (MIE), minimum ignition temperature (MIT), and minimum explosion concentration (MEC) of dust samples with different particle sizes were obtained. Using experimental data, a two-dimensional matrix analysis method was applied to classify the dust explosion severity based on Pmax and Kst. Then, a three-dimensional matrix was used to categorize the dust explosion sensitivity based on three factors: MIE, MIT, and MEC. Finally, a two-dimensional matrix model of dust explosion risk assessment was established considering the severity and sensitivity. The model was used to evaluate the explosion risk of polyethylene dust samples with different particle sizes. It was found that the risk level of dust explosion increased with decreasing particle size, which was consistent with the actual results. The risk assessment method can provide a scientific basis for dust explosion prevention in the production of polyethylene.

In this paper, we focus on a semi-online scheduling problem with rejection on identical parallel machines, where “semi-online” means that the ratio of the longest processing time among all jobs to the shortest one is no more than γ with γ ≥ 1. In particular, in this setting, there are a coupling of independent jobs arriving online over time with the flexibility of rejection, which implies that each job will be either accepted and scheduled on one of identical machines or rejected at the cost of penalty cost. Our objective is minimizing the total completion time of the accepted jobs plus the total penalty cost of the rejected jobs. For this problem, we design a deterministic polynomial time semi-online algorithm entitled as α Delayed Shortest Processing Time with Rejection (ADSPTR). In competitive analysis, by adopting the approach “Improved Instance Reduction”, we obtain the competitive ratio of ADSPTR is at most 1 + 1 + γ ( γ − 1 ) − 1 γ .

3D holoscopic imaging, also known as integral imaging, light field imaging or plenoptic imaging, can provide natural and fatigue-free 3D visualization. Holoscopic contents captured by the plenoptic camera contain both spatial and angular information of a 3D scene. Therefore, view images with different perspectives can be rendered from the holoscopic contents. A coding scheme to compress the 3D holoscopic image by exploiting the high spatial correlation among the rendered view images will be advantageous. Therefore, in this paper, an efficient scalable coding scheme is proposed to compress the 3D holoscopic image by utilizing such high spatial correlation. We firstly re-arrange the holoscopic contents to form an interlaced view image. A sparse format is then proposed to express the interlaced view image. With the reconstructed image derived by disparity map based sifting and interpolation, the full interlaced view image is coded by using the reconstructed image as a reference frame. As an outcome of the representation, a scalable structure with three layers can be provided by the proposed scheme. Experimental results demonstrate that the 3D holoscopic image can be compressed efficiently with over 44 percent bit rate reduction compared with HEVC. Meanwhile, the proposed scheme can also surpass several other prediction schemes in this field.

TiO 2−x MgO: 0.1 at% Mn 4+ (1 ≤ x ≤ 2) red phosphors are synthesized through a traditional high temperature solid-state reaction method. The excitation and emission spectra indicate that 700 nm and 660 nm red emission peaks are ascribed to Mn 4+ ions doped in MgTiO 3 and Mg 2 TiO 4 , respectively. The Ti 4+ octahedron is connected in MgTiO 3 by O 2− ions of the octahedrons, while the Ti 4+ octahedron is separated in Mg 2 TiO 4 by Mg 2+ tetrahedron and Mg 2+ octahedron. This results that the quenching concentration is higher in Mg 2 TiO 4 than in MgTiO 3 leading the less luminous centers in MgTiO 3 . Detailed spectroscopic and crystal-field studies of the Mg 2 TiO 4 : Mn 4+ and MgTiO 3 : Mn 4+ is described in the present paper.

Purpose. With the development of digital X-ray imaging and processing methods, the categorization and analysis of massive digital radiographic images need to be automatically finished. What is crucial in this processing is the automatic retrieval and recognition of radiographic position. To address these concerns, we developed an automatic method to identify a patient’s position and body region using only frequency curve classification and gray matching. Methods. Our new method is combined with frequency analysis and gray image matching. The radiographic position was determined from frequency similarity and amplitude classification. The body region recognition was performed by image matching in the whole-body phantom image with prior knowledge of templates. The whole-body phantom image was stitched by radiological images of different parts. Results. The proposed method can automatically retrieve and recognize the radiographic position and body region using frequency and intensity information. It replaces 2D image retrieval with 1D frequency curve classification, with higher speed and accuracy up to 93.78%. Conclusion. The proposed method is able to outperform the digital X-ray image’s position recognition with a limited time cost and a simple algorithm. The frequency information of radiography can make image classification quicker and more accurate.

Two series of novel phosphors of green-yellow emitting Ca8−xSrxMgGd(PO4)7:Eu2+ and yellow-orange emitting Sr8MgGd(PO4)7:Eu2+,yMn2+ were successfully synthesized by a solid-state reaction. The crystal structures, photoluminescence (PL), PL excitation (PLE) spectra and decay times were investigated in detail. Upon excitation at 350 nm, the Ca4Sr4MgGd(PO4)7:Eu2+ phosphor showed strong green emission centered at 513 nm, and the Sr8MgGd(PO4)7:Eu2+ phosphor showed strong yellow emission centered at 513 nm and 593 nm, and Sr8MgGd(PO4)7:Eu2+,Mn2+ showed strong orange emission centered at 510 nm and 616 nm. In addition, a standard warm white-light emitting single-phased phosphor of Sr8MgGd(PO4)7:Eu2+,Mn2+ with chromaticity coordinates (x, y), correlated color temperature (CCT) and Commission Internationale de l'Eclairage (CIE) coordinates of (0.4497, 0.3929), 2705 K, and 89.7 was realized via energy transfer between Eu2+ and Mn2+. The energy transfer was demonstrated to be a resonant type dipole–quadrupole mechanism. Moreover, the obtained LED device exhibits an excellent color-rendering index (Ra = 97) at a correlated color temperature of 5651 K with the CIE coordinates (0.3290, 0.3410).

Fog and haze represent the most hazardous type of weather affecting the life and health of residents in China since 2009; as a result, many policymakers and economists have focussed on this issue. This study analyses the driving factors of fog and haze in 152 cities in China from the perspective of the economic effect. Considering the spatial attributes of fog and haze alongside the regional economic association, a spatial economic weight matrix is constructed and introduced into a spatial autoregressive model to analyse the spatial diffusion effect of PM 2.5 pollution. The results show that PM 2.5 pollution has significant spatial aggregation and diffusion effects that are significantly influenced by geospatial attributes and regional economic association in China. Furthermore, the effects of economic, social, and technological factors exhibit significant differences in relation to PM 2.5 in different cities, and all of these factors present regional spillover effects. Specifically, the relationship between PM 2.5 and economic development in China is consistent with the Environmental Kuznets Curve (EKC) hypothesis, in which different regions are located at different positions on the EKC curve due to the different situations related to economic development. As a result, the regional coordination of environmental policies and pollution-intensive industry transfer are needed to hold China's air pollution in check.