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The growing demand for outpatient departments and prolonged waiting time of patients in recent years has made physician scheduling necessary to provide timely medical services. This study focused on the problem of scheduling physicians in an outpatient system with a nonhomogeneous patient arrival and priority queue, which exists in many Asian hospitals. In such a system, both patients with appointments and walk-in patients wait in a priority queue to see physicians, with the patients’ arrivals fluctuating throughout the day. In order to respond to time-related demands while simultaneously respecting physicians’ preferences for being on or off duty in some specific slots, a staffing optimization model was formulated. In addition, a physician rescheduling model was proposed for the case where a physician is unexpectedly absent. To solve the problem, a calibrated waiting time approximation-based genetic algorithm methodology was proposed. Its main contribution is the use of a data-driven analytical method to estimate the average waiting time of the two types of patients in a complex queuing system. The results of a numerical study and real case study in a Shanghai hospital showed that physician scheduling optimization on the basis of the proposed waiting time approximation method was effective and efficient when applied to the proposed outpatient system.

Despite its simplicity and high accuracy, the real-time efficiency of OTSU segmentation is not high. In order to promote the real-timeliness of image segmentation, this paper introduces the fruitfly optimization algorithm (FOA) to OTSU segmentation, creating an FOA-OTSU segmentation algorithm. In the proposed algorithm, the optimal threshold for segmentation is searched for by the FOA. The classic Lena picture, Flower picture and Cameraman picture were used for simulation experiment, and the results were evaluated by signal-to-noise ratio (SNR) and peak signal-to-noise ratio (PSNR). The results show that the segmentation time is reduced by about 50.0% on the premise of the PSNR and SNR evaluation criteria and the segmentation effect basically unchanged. The simulations indicate that our method converges faster and consumes fewer time than traditional OTSU algorithm, without sacrificing the segmentation accuracy. The research provides a desirable tool with high real-time performance of rapid image segmentation.

The urban heat island (UHI) effect in cities and its driving factors have long been investigated. 3-D buildings are key components of urban structures and have notable effect on the UHI effect. However, due to the incomplete 3-D building information in urban database, only a few studies investigated the impact of 3-D building morphology factors on the land surface temperature (LST). In this study, a total set of 14 2-D and 3-D building morphology factors were selected to investigate the correlation between UHI and building morphology across three megacities in China (Beijing, Wuhan, Shanghai) with Landsat-8 LST scenarios in summer and winter of 2018 and 2019, respectively. Both Spearman correlation and partial correlation analysis were applied at block scale after urban functional zone (UFZ) mapping. A number of significant observations were noted based on the multispatial and multitemporal experimental results:1) both 2-D and 3-D building morphology factors influence LST, among them building coverage ratio, building ground area divided by facade area (GA2FA), and sky view factor yield stronger correlations with LST; 2) UFZ mapping scheme and partial correlation method help with controlling the anthropogenic heat release, greenspace, and water bodies coverage variables when targeting at the influence of building morphology factors on LST. This study provides insights for building morphology design in future urban planning and management.

Solvent-free and highly branched water-soluble polyester (WPET) is prepared through self-emulsification methodology, using dimethyl terephthalate (DMT), sodium dimethyl isophthalate-5-sulfonate (SIPM), trimethylolpropane (TMP), and ethylene glycol (EG) by the transesterification and polycondensation. The WPET were first utilized as surface-sizing agents for cellulose fiber paper. The structure, average molecular weights, and physical properties of the water-soluble polyester were characterized by FTIR, 1H NMR, gel permeation chromatography (GPC), dynamic light scattering (DLS), X-ray diffraction (XRD), and dynamic rheometer. The effects of polymer structure and properties, as well as the surface sizing of the paper, were investigated. WPET displayed better surface sizing properties when it was prepared under the following conditions: –COO/–OH molar ratio of 1:2, the SIPM content of 17.98%, and TMP content of 11.10%. The relationships between the WPET structure and sized paper were clearly illustrated. The mechanical properties and water resistance of sized paper did not only depend on multi-branched hydroxyl groups of the WPET chains but also relied on the interactions among polymers and fibers, as well as the high toughness of surface sizing agent. The sizing paper possesses excellent mechanical properties as well as water resistance.

Epoxy resin is widely used in metal surface protection, because of corrosion resistance and adhesion. However, it’s water solubility, oxygen, and water impermeability are not enough. In this paper, linoleic acid (LOFA) and epoxy resin (E20) were used to synthesize epoxy ester (EL) and grafted with phosphonate esterified acrylic resin (AR-P) to prepare acrylic grafted epoxy ester (EL@AR-P). After modification, water solubility and film-forming property were improved, and the oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) decreased. At the addition of PM-2 at 2%, the OTR, WVTR, and water-uptake rate decreased by 12.9%, 25.0%, and 12.1%, respectively. Subsequently, the modified material was subjected to electrochemical impedance spectroscopy. The low-frequency impedance of EL@AR-P2 is three times higher than EL@AR-P0. After 16 days of immersion, the low-frequency impedance of EL@AR-P2 is 20 times higher than EL@AR-P. Energy dispersive spectrometer and X-ray photoelectron spectroscopy results showed that the P elements were concentrated on the substrate surface and found the presence of P–O–Fe bonds, demonstrating that the phosphonate groups were migrated to the substrate surface to form a chelate layer with the substrate and enhancing the coating adhesion and corrosion resistance. This paper modifies the molecular structure of epoxy resin, which is expected to be an excellent material for anti-corrosion coatings.

SnS is considered as a promising anode candidate for next-generation Li- and Na-ion batteries due to its high theoretical capacity and large interlayer distance, which provides excessive space for intercalation of Li- and Na-ions. However, the low electronic conductivity and large volumetric changes during charge/discharge process lead to its poor rate capability and severe capacity degradation. Herein, a sandwich-like SnS/N, S co-doped rGO/SnS structure is delicately tailored by using selective vulcanization and in situ decomposition processes. The unique sandwich-like SnS/rGO/SnS structure provides open channels for ion storage and ameliorates the electrical conductivity. RGO substrate and chemical bonds between SnS and rGO improves the electronic conductivity and furnishes additional ions/electrons transport routes. Moreover, the co-doping of N and S renders abundant sites for ions adsorption, inducing a strong pseudocapacitance effect and favoring fast electrochemical kinetics. Therefore, at the current density of at 1 A g−1, the sandwich-like SnS/rGO/SnS electrode delivered a high reversible capacity of 797.9 mAh g−1 and 359.2 mAh g−1 as an anode material in Li- and Na-ion batteries, respectively.

Many vision-based applications rely on logistic regression for embedding classification within a probabilistic context, such as recognition in images and videos or identifying disease-specific image phenotypes from neuroimages. Logistic regression, however, often performs poorly when trained on data that is noisy , has irrelevant features , or when the samples are distributed across the classes in an imbalanced setting ; a common occurrence in visual recognition tasks. To deal with those issues, researchers generally rely on ad-hoc regularization techniques or model a subset of these issues. We instead propose a mathematically sound logistic regression model that selects a subset of (relevant) features and (informative and balanced) set of samples during the training process. The model does so by applying cardinality constraints (via $\ell _0$ l 0 -‘norm’ sparsity) on the features and samples. $\ell _0$ l 0 defines sparsity in mathematical settings but in practice has mostly been approximated (e.g., via $\ell _1$ l 1 or its variations) for computational simplicity. We prove that a local minimum to the non-convex optimization problems induced by cardinality constraints can be computed by combining block coordinate descent with penalty decomposition. On synthetic, image recognition, and neuroimaging datasets, we show that the accuracy of the method is higher than alternative methods and classifiers commonly used in the literature.

Generalized Zero-shot learning (GZSL) for object recognition is to solve the problem of recognizing samples in both seen and unseen classes, while only having seen classes in training. As labeling abundant examples for all kinds of classes in realistic scenarios is costly and impractical, GZSL has become a novel and hot field of research in recent years. Most previous methods tried to learn a fixed one-directional mapping, either from visual to semantic features, or from semantic to visual features. However, recently, cross mapping between visual and semantic features has achieved good results and many methods come up based on this idea. In this paper, we propose a novel model. It is Multi-channel Gaussian Mixture VAE(MCGM-VAE), which introduces Gaussian mixture model to our multi-modal VAE with multiple channels. These channels are of different weight coefficients following with channel-weight layers, so as to produce a Gaussian mixture distribution. Then the latent space could be generated from it. We evaluate our method on several benchmark databases, i.e. CUB, SUN, AWA1, AWA2, aPY and prove our approach outperforms state-of-the-art methods. Through the experimental data analysis, the impact of some hyperparameters on the experimental performance is further analyzed.

We experimentally demonstrate an integrated strictly non-blocking silicon 4 × 4 optical switch chip that can be operated in both thermo-optic (TO) and electro-optic (EO) switching modes. It is based on the double-layer network (DLN) architecture and consists of twelve 2 × 2 Mach-Zehnder interferometer (MZI) switch elements. TO phase shifters based on TiN microheaters and EO phase shifters based on p-i-n diodes are embedded in both waveguide arms of the MZI elements. The power consumption for TO and EO switching is 34 mW/π and 7 mW/π, respectively. The on-chip insertion losses are 1.74 ± 0.59 dB and 3.79 dB ± 1.32 dB for TO and EO switching, respectively. Due to the merits of the DLN architecture and the optimized performance of the switch elements, the chip possesses low crosstalk of -29.1 dB and -19.4 dB for TO and EO switching, respectively. Quadrature phase-shift keying (QPSK) optical signals with a data rate of 64 Gb/s are transmitted through the switch with no observable deteriorations. Such an optical switch is a promising candidate for both optical circuit switching and optical packet switching for a variety of applications.

The natural DNA double helix consists of two strands of nucleotides that are held together by multiple hydrogen bonds. Here we propose to build an artificial double helix from fragments of two strands connected by covalent linkages therein, but with halogen bonding as the driving force for self-assembling the fragments to the double helix. We succeed in building such a double helix in both solution and solid state, by using a bilateral N-(p-iodobenzoyl)alanine based amidothiourea which in its folded cis-form allows double and crossed C−I···S halogen bonds that lead to right- or left-handed double helix when the two alanine residues are of the same L,L- or D,D-configuration. The double helix forms in dilute CH3CN solution of the micromolar concentration level, e.g., 5.6 μM from 2D NOESY experiments and exhibits a high thermal stability in solution up to 75 °C, suggesting cooperative and thereby strong intermolecular double crossed halogen bonding that makes the double helix stable. This is supported by the observed homochiral self-sorting in solution., Building an artificial double helix is a compelling challenge, and most strategies rely on the intertwining of two helical strands. Here, in a very different approach, the authors construct a supramolecular double helix from multiple synthetic small molecules chained together by double crossed halogen bonds.

Phosphorylated graphene oxide (PedGO) was synthesized through the in-situ phosphate esterification method with urea as catalyst and then embed into waterborne acrylate-epoxy resin emulsion (AE) coating to modify the coating. The TEM and AFM indicated that phosphate was uniformly decorated on GO sheets, forming a large phosphorylated graphene oxide sheets. The PedGO improved the water vapor permeability and the coating adhesion strength after 30 days of immersion in 3.5% NaCl of AE coatings, respectively. Electrochemical impedance spectroscopy measurements (EIS) revealed that the PedGO-modified AE (PedGO/AE) was an outstanding barrier against corrosive media compared with AE or GO-modified AE (GO/AE). Scratch tests also showed that the corrosion-promotion effect of PedGO in AE was inhibited. The enhanced corrosion protection performance was observed because on the one hand the PedGO can greatly prolonged the diffusion pathway of corrosive media in the coating matrix; on the other hand the organic p...

Solution-based processing of two-dimensional (2D) materials provides the possibility of allowing these materials to be incorporated into large-area thin films, which can translate the interesting fundamental properties of 2D materials into available devices. Here, we report for the first time a novel chemical-welding method to achieve high-performance flexible n-type thermoelectric films using 2D semimetallic TiS2 nanosheets. We employ chemically exfoliated TiS2 nanosheets bridged with multivalent cationic metal Al3+ to cross-link the nearby sheets during the film deposition process. We find that such a treatment can greatly enhance the stability of the film and can improve the power factor by simultaneously increasing the Seebeck coefficient and electrical conductivity. The resulting TiS2 nanosheet-based flexible film shows a room temperature power factor of ∼216.7 μW m–1 K–2, which is among the highest chemically exfoliated 2D transition-metal dichalcogenide nanosheet-based films and comparable to the b...

In-situ surfactant-free emulsion polymerization was utilized to prepare polyacrylate/polyurethane (PUA) microemulsions in the absence of surfactant and organic solvent. For this purpose, PUA with higher acrylate content was successfully prepared, with the aim to reduce the coating cost. The dynamic light scattering results showed that the particle size of PUA microemulsion displayed a unimodal distribution and the particle size was ranged from 33 to 61 nm. In comparison with PUA prepared with conventional miniemulsion polymerization, the particle size distribution coefficient dropped by one order. Atomic force microscopy, together with thermogravimetric analyzer, demonstrated good compatibility and interaction between PU and acrylic components, and no phase separation was detected even at 58 wt% acrylic content. With the incorporation of acrylic component, the thermal stability and maximum stress were improved. The maximum stress greatly increased from 4.6 to 30.9 MPa, and the maximum stress of in-situ PUA was nearly three times larger than that of PUA prepared by miniemulsion polymerization. The effects of acrylic content on water resistance, pencil hardness, adhesion, and impact strength of wood coating were evaluated. With increasing the acrylic content, the water resistance and pencil hardness increased, though the impact strength of in-situ PUA films was slightly reduced.

Impurities may have a marked effect on crystal nucleation and growth. To further understand the role of impurities, the crystallization (solubility, nucleation, growth) of succinic acid in water in the presence of surfactants such as polyethylene glycol sorbitan monooleate (Tween 80), cetyltrimethylammonium bromide (CTAB) and sodium dodecylbenzenesulfonate (SDBS) was investigated experimentally. The presence of CTAB, SDBS or Tween 80 had little influence on succinic acid solubility but did slow crystallization kinetics. The surfactant monomer in solution, not micelles, proved to play the primary role affecting nucleation. The nucleation inhibition by surfactant was analyzed on the base of a two-step nucleation process: (1) the inhibition on the formation and growth of succinic acid nanodroplets and (2) the influence on succinic acid single nucleus (SASN) in secondary nucleation. SASN may play important role in secondary nucleation, although further work is necessary to conform this. The length of the surfactant hydrocarbon chain was found to affect crystal habit development.

We first prepared an unsaturated epoxy resin ester (EM) by addition–esterification reaction with acrylic acid and then synthesized a series of acrylic ester/epoxy hybrid latexes (AE) with core–shell structure by semicontinuous emulsion polymerization method. The resultant AE emulsions are utilized as anticorrosion coatings of metals. The influences of EM content and crosslinking agent (PEG(400)DA) content on the physicochemical properties of the resultant emulsions and anticorrosion coatings of metals are investigated in detail. The AE emulsion displays better anticorrosion properties when it is prepared under the following conditions: the EM content of 30 wt% and PEG(400)DA content of 2.0 wt%. The relationships between the AE structure and anticorrosion properties of AE coatings are clearly illustrated. The corrosion resistances of AE coatings are not only depend on the crosslinking density, hydrophilic, and polarity among the AE chains, but also rely on the stability of the emulsion and the integrality and homogeneity of the coatings.

Walk-in patients can take a large portion of outpatient visits in comprehensive hospitals. In current common practice, an even number of appointments is assigned to each slot and patients with appointment are given a strictly higher priority than walk-in patients. As a result, walk-in patients usually wait longer and incur noticeable dissatisfaction. To improve their satisfaction, we propose an integrated optimization approach for patient-centred outpatient scheduling. This approach aims to allocate appointments in line with the temporal variation of patient walk-ins, and further develop a time-invariant threshold-based prioritization scheme to balance the service priorities between the two types of patients in real time. To substantiate this approach, we develop a prospect theory-based model to quantify each patient’s real-time satisfaction. We apply discrete-event simulation-based optimization to maximize the average patient satisfaction over the two types of patients. To verify our integrated optimization approach, we conduct a pilot in the endocrine department of Shanghai Sixth People’s Hospital. Our results suggest that our approach substantially decreases the waiting time of walk-in patients without much compromise on the satisfaction of patients who made advance appointment.

Rhenium is one of the most valuable elements found in nature, and its capture and recycle are highly desirable for resource recovery. However, the effective and efficient collection of this material from industrial waste remains quite challenging. Herein, a tetraphenylmethane-based cationic polymeric network (CPN-tpm) nanotrap is designed, synthesized, and evaluated for ReO4 - recovery. 3D building units are used to construct imidazolium salt-based polymers with positive charges, which yields a record maximum uptake capacity of 1133 mg g-1 for ReO4 - collection as well as fast kinetics ReO4 - uptake. The sorption equilibrium is reached within 20 min and a kd value of 8.5 × 105 mL g-1 is obtained. The sorption capacity of CPN-tpm remains stable over a wide range of pH values and the removal efficiency exceeds 60% for pH levels below 2. Moreover, CPN-tpm exhibits good recyclability for at least five cycles of the sorption-desorption process. This work provides a new route for constructing a kind of new high-performance polymeric material for rhenium recovery and rhenium-contained industrial wastewater treatment.

The objective of digital broadcasting has evolved from providing a plain video service to offering a realistic visual experience. Technologies such as 3DTV and UHDTV have been suggested to achieve this new objective by providing an immersive and stereoscopic visual experience. However, owing to the high bandwidth requirements of such services, the broadcasting industry has faced a challenge to find a new transport mechanism for overcoming the bandwidth limitation. The standardization organizations, the Advanced Television Systems Committee, Digital Video Broadcasting, and Telecommunications Technology Association, have been working on the integration of broadcasting and a broadband network (IP) to resolve the bandwidth issue of realistic video services. This paper introduces a frame-level timeline synchronization and transport system target decoder model for providing a stable 3DTV service over a hybrid network. The experimental results indicate that the proposed technologies can be successfully adopted as a reference model in a broadcast-broadband hybrid 3DTV service and other IP-associated hybrid broadcasting services.

A directly coating method, controlled double-jet precipitation (CDJP), was developed for synthesizing magnetic Fe3O4@Cu(OH)2 composites in combination of advantages of magnetic rapid separation and satisfactory adsorption performance. The morphology and structure of the composites were analyzed by SEM, TEM, XRD, FTIR, XPS and VSM techniques. Through controlling the reaction on Fe3O4 particles, directly coating of Cu(OH)2 was successfully realized without the extra complicated procedures. The obtained Fe3O4@Cu(OH)2 consists of micro particles of size around 250 nm coated with special leaflike nanomorphologies, possessing high saturation magnetization (from 56.5 to 98.84 emu g−1). As the amount of loaded Cu increased, As(V) removal of the composites augmented from 11.11 to 35.71 mg g−1 far beyond that of reported traditional magnetic adsorbents. The adsorption isotherm was best fitted by Langmuir adsorption mode and the mechanism was mainly ascribed to the OH functionality of the Fe3O4@Cu(OH)2 composites and electrostatic attraction between As(V) species and Fe3O4@Cu(OH)2 composites. The Fe3O4@Cu(OH)2 composites is a promising candidate for treating arsenic contaminated water.

Individual tree segmentation is essential for many applications in city management and urban ecology. Light Detection and Ranging (LiDAR) system acquires accurate point clouds in a fast and environmentally-friendly manner, which enables single tree detection. However, the large number of object categories and occlusion from nearby objects in complex environment pose great challenges in urban tree inventory, resulting in omission or commission errors. Therefore, this paper addresses these challenges and increases the accuracy of individual tree segmentation by proposing an automated method for instance recognition urban roadside trees. The proposed algorithm was implemented of unmanned aerial vehicles laser scanning (UAV-LS) data. First, an improved filtering algorithm was developed to identify ground and non-ground points. Second, we extracted tree-like objects via labeling on non-ground points using a deep learning model with a few smaller modifications. Unlike only concentrating on the global features in previous method, the proposed method revises a pointwise semantic learning network to capture both the global and local information at multiple scales, significantly avoiding the information loss in local neighborhoods and reducing useless convolutional computations. Afterwards, the semantic representation is fed into a graph-structured optimization model, which obtains globally optimal classification results by constructing a weighted indirect graph and solving the optimization problem with graph-cuts. The segmented tree points were extracted and consolidated through a series of operations, and they were finally recognized by combining graph embedding learning with a structure-aware loss function and a supervoxel-based normalized cut segmentation method. Experimental results on two public datasets demonstrated that our framework achieved better performance in terms of classification accuracy and recognition ratio of tree.

This study presented a composite biomaterial ink consisting of GelMA, decellularized extracellular matrix (DECM) and nanoclay for printing 3D scaffolds for primary hepatocytes cultivation. In this biomaterial ink, the proportion of DECM was 75%, which is the highest value ever reported. The high proportion of DECM resulted in high activity of primary hepatocytes, and enabled better organ-specific biomaterial ink.

Sulfur (S) application in pakchoi (Brassica chinensis L.) cultivation is vital for reducing cadmium (Cd) accumulation in the plants. However, the mechanism of S application on Cd uptake and translocation in pakchoi is unclear. In this study, a hydroponic experiment was performed to investigate the effects of S application on Cd accumulation in pakchoi at one Cd concentration (50 μM, in comparison to the control condition, 0 μM) and three S levels (0, 2, 4 mM). The results showed that excessive S application (4 mM) reduced Cd accumulation and alleviated pakchoi growth inhibition caused by Cd stress in shoots and roots. With increased S application, the proportion of Cd in the vacuolar fraction and the proportion of NaCl-extractable Cd increased in roots. Additionally, S application increased the content of glutathione (GSH) and phytochelatins (PCs). The reduced Cd uptake and accumulation in pakchoi shoots could have been due to increased Cd chelation and vacuolar sequestration in roots. In addition, sufficient S application (2 mM) increased the expression of γ-glutamylcysteine synthetase (GSH1) and nicotinamide synthase (NAS) in roots, and excessive S application upregulated the expression of ATP sulfurylase (ATPS) and phytochelatin synthase (PCs). This study provides evidence for the mechanism of mitigating Cd toxicity in pakchoi and will be helpful for developing strategies to reduce Cd accumulation in the edible parts of pakchoi through S fertilizer application.

Fully oriented-intermetallic interconnects (FOI) of high melting point and service performance have highly considerable potential application in the current generation of 3D electronic packaging. The primary process of fabrication of this structure is the Cu6Sn5 preferred nucleation. In this article, the orientations of 59 successive Cu6Sn5 grains along the radius of (0 0 1)Cu/Sn-3.0Ag solder interface were investigated. Finally, an analysis and control model of Cu6Sn5 preferred nucleation determined by chemical potential gradient of Cu migration was established and applied to address and manage the orientation growth of Cu6Sn5 under different reflow temperatures and solder compositions. The results pave the way for orientation controlling of interfacial intermetallics in 3D packaging technologies.

Cu-N-C electrocatalyst was successfully prepared with Cu-BTC and polyacrylonitrile as templates by electrospinning and in-situ growth method. The effect of various [Formula: see text]-doped content on the electrochemical performance of the catalyst were investigated and the Cu-N-C-0.25 exhibited the best OER/ORR catalytic activities. When it was applied to the cathode of the zinc-air batteries, the power density of Cu-N-C-0.25 was 209.1[Formula: see text]mW[Formula: see text]cm[Formula: see text], which exceeded that of the commercial Pt/C[Formula: see text]IrO2 hybrid catalyst (157[Formula: see text]mW[Formula: see text]cm[Formula: see text]). The excellent electrochemical performance may be attributed to large number of active sites and high specific surface area on Cu-N-C electrocatalyst. It will be a promising alternative to precious metal catalysts containing Pt, Ir or Ru and their oxides.

Cationic poly(urethane-acrylate) emulsifier-free microemulsions are prepared by seeded emulsion polymerization (SPUA) or in-situ emulsion polymerization (IPUA) with (a) or without (b) crosslinking agent hydroxyethyl acrylate (HEA). Furthermore, no surfactant is introduced into the reaction system. The effect of continuous phase and HEA on the rheological behavior and properties of microemulsions are studied. The results show that IPUA using vinylmonomers as the continuous phase and with HEA (IPUAMB-b) has the highest ζ value, lowest coagulation ratio, smallest particle size of 48 nm and apparent core–shell structures. Rheological research has concluded that the zero-shear viscosity of IPUAB-b and IPUAM-b emulsion is 6.03×102 and 7.89 Pa·s, respectively, and presents pseudoplastic behavior. However, IPUAMB-b and SPUA-b display Newtonian behavior with η0 of 0.136 Pa·s and 0.0823 Pa·s, respectively. PUA emulsions display similar rheological behavior when NMP is replaced by the mixture of MMA and BA.

As one of the most important applications in peer-to-peer (P2P) networks, the video-on-demand (VoD) system freely supports video cassette recorder (VCR) operation for users. However, the users may experience significant playback delay after frequent VCR operations in the VoD system, which will affect the quality of experience (QoE) of the users. Hence, selecting an appropriate data-prefetching strategy to support better VCR operation is an important approach to improve the QoE. This paper proposes a data-prefetching strategy (DSA) to determine the most suitable anchor interval by considering the playback delay and positioning satisfaction. According to the DSA, we use the multiple-attribute decision-making (MADM) theory to model the selection of intervals of prefetching data blocks (i.e., anchor interval) and the technique for ordering preference by similarity to an ideal solution (TOPSIS) algorithm to solve the MADM. The simulation results show that the DSA strategy obtains higher positioning satisfaction than the existing schemes, which is approximately 60% higher than the anchor points, popular parts of video, and user interests (API)-based method. Moreover, with the increase in network bandwidth, the DSA strategy can minimize the playback delay after VCR operation using relative few extra bandwidths.

Here, we demonstrate a phosphorodiamidate morpholino oligos (PMO)-functionalized nanochannel biosensor for label-free detection of microRNAs (miRNAs) with ultrasensitivity and high sequence specificity. PMO, as a capture probe, was covalently anchored on the nanochannel surface. Because of the neutral character and high sequence-specific affinity of PMO, hybridization efficiency between PMO and miRNAs was enhanced, thus largely decreasing background signals and highly improving the detection specificity and sensitivity. The miRNAs detection was realized through observing the change of surface charge density when PMO/miRNAs hybridization occurred. Not only could the developed biosensor specifically discriminate complementary miRNAs (Let-7b) from noncomplementary miRNAs (miR-21) and one-base mismatched miRNAs (Let-7c), but also it could detect target miRNAs in serum samples. In addition, this nanochannel-based biosensor attained a reliable limit of detection down to 1 fM in PBS and 10 fM in serum sample, respectively. It is expected that such a new method will benefit miRNA detection in clinical diagnosis.

Highly flexible and porous films with the ability to load various nanoscale adsorbents are of particular importance in the purification field. Herein, we report the sustainable and large-scale fabrication of a porous and flexible hybrid film based on the graphene oxide/hyphae interaction at a relatively low temperature of 130 °C. Under identical conditions, such films cannot be constructed with solely graphene oxide or hyphae. Moreover, through the addition of nanoscale building blocks [e.g., nanoscale poly(m-phenylenediamine) (PmPD) adsorbents] in the interaction process, the nanoparticles can be in situ loaded into the film. According to FTIR and XPS analyses, the film formation mechanisms mainly involve redox and cross-linking reactions between graphene oxide and fungus hyphae. In a proof-of-concept study, a PmPD nanoparticle-loaded hybrid film was used as a superior key component to build a flow-through adsorption device that displayed a promising adsorption performance toward dye pollutants.

To achieve the flexible and efficient transmission of files in the video on demand system, this paper proposed a three-tier fragmentation strategy which provided a unfiled method of fragmentation for video of HTTP Live Streaming and large file. In order to prove the rationality of the three-tier fragmentation strategy, we compared it with the two layers fragmentation strategy and the fragmentation strategy of equal time. And the comparisons proved the superiority of three-tier fragmentation strategy.

A type of water dispersible graphene (PG) has been synthesized by nucleophilic ring-opening reaction of the primary amine group in 3-(1-(2-aminopropoxy) propan-2-ylamino) propane-1-sulfonate sodium (PPS) with epoxy groups on the basal plane of graphene oxide (GO), followed by in situ reduction with hydrazine hydrate. The PG is employed as nanoscale reinforcement fillers in waterborne acrylic modified alkyd resin (AMAR) coatings. The stability and corrosion resistance of the waterborne PG/AMAR nanocomposite coatings are investigated. SEM and stability of nanocomposite indicated that the PG sheet is uniformly distributed in AMAR nano-emulsion. Potentiodynamic polarization and electrochemical impedance spectroscopy studies indicated that the PG/AMAR composite coatings exhibit higher corrosion resistance in simulated body fluid (SBF) compared with pure AMAR coatings and GO/AMAR coatings. In addition, the stability and corrosion resistance of the composite materials reach optimum when the PG content is 1%. PPS functionalized graphene (PG) displays prospective application in anticorrosion field. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44445.

A series of waterborne polyurethane (WPU) microemulsions were synthesized through self-emulsification methodology, using toluene-2,6-diisocyanate, polytetramethylene glycol (PTMG), poly-caprolactonediol (PCL), and dimethylol propionic acid (DMPA) as monomers; isophorone diamine (IPDA) as chain extender; and aziridine as cross-linking agent. The resultant WPU microemulsions were utilized as surface-sizing agents for cellulose fiber paper. The influences of IPDA content, PTMG/PCL molar ratio, and aziridine content on the physicochemical properties of the resultant emulsions and sized paper have been investigated in detail. The WPU microemulsion displayed better surface sizing properties when it was prepared under the following conditions: the IPDA content of 2.96%, PTMG/PCL molar ratio of 0:4, and aziridine content of 2.0 wt %. The relationships between the WPU structure and properties of WPU films and sized paper were clearly illustrated. The mechanical properties and water resistance of sized paper were not only depended on the interactions, chain entanglements, and cross-linking density among the WPU chains, but also relied on the interactions among polymers and fibers, as well as the polarity and stiffness of surface sizing agent. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43211.

A fully hydraulic variable valve system based on spark-ignition engine BJ486EQ is introduced in this article, which can provide fully variable valve lifts, valve timing, and valve opening duration. A simulation model of fully hydraulic variable valve system is established, which is verified through experimental intake valve lift and hydraulic pressure. It is found that pressure fluctuation in hydraulic system of fully hydraulic variable valve system becomes greater with the increase in engine speed, which even leads to “lift distortion.” The cam profile of fully hydraulic variable valve system and the structure of the throttling valve which is used to reduce valve seating speed are optimized by simulation. The lift distortion and rebound do not occur in the optimized fully hydraulic variable valve system, which is indicated by the results of simulation and experiments when the engine speed is 5000 r/min, and valve seating characteristics become stable and soft.

In the context of sparse recovery, it is known that most of existing regularizers such as $\ell_1$ suffer from some bias incurred by some leading entries (in magnitude) of the associated vector. To neutralize this bias, we propose a class of models with partial regularizers for recovering a sparse solution of a linear system. We show that every local minimizer of these models is sufficiently sparse or the magnitude of all its nonzero entries is above a uniform constant depending only on the data of the linear system. Moreover, for a class of partial regularizers, any global minimizer of these models is a sparsest solution to the linear system. We also establish some sufficient conditions for local or global recovery of the sparsest solution to the linear system, among which one of the conditions is weaker than the best known restricted isometry property (RIP) condition for sparse recovery by $\ell_1$. In addition, a first-order feasible augmented Lagrangian (FAL) method is proposed for solving these models, in which each subproblem is solved by a nonmonotone proximal gradient (NPG) method. Despite the complication of the partial regularizers, we show that each proximal subproblem in NPG can be solved as a certain number of one-dimensional optimization problems, which usually have a closed-form solution. We also show that any accumulation point of the sequence generated by FAL is a first-order stationary point of the models. Numerical results on compressed sensing and sparse logistic regression demonstrate that the proposed models substantially outperform the widely used ones in the literature in terms of solution quality., Comment: 35 pages, 4 figures

With the rapid development of modern communication technology, all kinds of radio technologies emerge endlessly. As different wireless networks share the same spectrum, coexistence of the heterogeneous networks becomes a challenging problem, especially the coexistence between ZigBee and WiFi. Much research has been done to solve this problem, and some coexistence methods have been proposed, such as the spectrum allocation, power control and so on. However, the proposed methods are either too complex to implement or need additional hardware cost. This paper proposes an easy and feasible method called AHA for ZigBee. The method modifies the current FEC coding method and additionally colligates energy sensing and adaptive retransmission. By implementing the method on ZigBee using USRP N210 devices, it is demonstrated that AHA effectively improves the communication performance of ZigBee under WiFi interference.