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Aiming at the problem that there exist lacks of analysis of the elastic properties of screen panel materials and research on the influence of mineral impact on the deflection changes of screen panel in response to the theory of large deflection deformation of flip-flow screen surface. Considering the scalability of the flip-flow screen panel material, a theoretical model of large deflection nonlinear elastic deformation of the screen panel is established. Combining with the external excitation sine displacement function, the time-domain expression of the screen panel with different amplitudes and frequencies is proposed for the first time. A testing platform for the dynamic characteristics of the flip-flow screen panel is built to verify the accuracy of the theoretical model in describing the deflection change process of the screen panel, and the optimal vibration parameters of the large deflection elastic deformation theory in describing the dynamic characteristics of the screen panel is clarified using the response surface optimization method. Based on the theory of large deflection elastic deformation of unloaded screen panel, a deflection variation theory of screen panel when particles collide with screen panel is proposed, and the deflection curve of screen panel with different motion states under particle impact force is calculated. Then the influence of different physical parameters on the local deformation degree of the collision point between the screen panel and mineral particles is revealed, and the accuracy of the theoretical expression of the deflection change of the screen panel under the collision of particles is verified through simulation experiments in describing the dynamic characteristics of the screen panel using different initial constraints. The research results show that the error rate of the experiments and theory of large deflection elastic deformation of screen panel under dynamic conditions is below 6%. The theoretical and experimental error rates of large deflection elastic deformation of the screen panel under dynamic conditions decrease with the increase of amplitude and frequency, but this change is nonlinear. When the amplitude is 7.33 mm and the frequency is 11.75 Hz, the error rate between the theoretical and experimental values at each measuring point reaches the lowest, and the average error rate at the midpoint of the screen panel is less than 3%. The incident angle of particles, the position of the impact point, the installation angle of the screen panel, and the operating state are important factors that affect the degree of local deformation of the screen panel during impact. Theoretical proof is shown that when the inclination angle and particle incidence angle of the screen surface installation are large, and the screen panel near the midpoint position move to the highest point, the collision between particles and the screen panel can obtain the maximum initial kinetic energy, and there is an average error of less than 4 mm between deflection deformation theory of the screen panel after collision in describing the impact point position and simulation results.

The molecular landscape and the intratumor heterogeneity (ITH) architecture of gastric linitis plastica (LP) are poorly understood. We performed whole‐exome sequencing (WES) and T‐cell receptor (TCR) sequencing on 40 tumor regions from four LP patients. The landscape and ITH at the genomic and immunological levels in LP tumors were compared with multiple cancers that have previously been reported. The lymphocyte infiltration was further assessed by immunohistochemistry (IHC) in LP tumors. In total, we identified 6339 non‐silent mutations from multi‐samples, with a median tumor mutation burden (TMB) of 3.30 mutations per Mb, comparable to gastric adenocarcinoma from the Cancer Genome Atlas (TCGA) cohort (P = 0.53). An extremely high level of genomic ITH was observed, with only 12.42%, 5.37%, 5.35%, and 30.67% of mutations detectable across 10 regions within the same tumors of each patient, respectively. TCR sequencing revealed that TCR clonality was substantially lower in LP than in multi‐cancers. IHC using antibodies against CD4, CD8, and PD‐L1 demonstrated scant T‐cell infiltration in the four LP tumors. Furthermore, profound TCR ITH was observed in all LP tumors, with no T‐cell clones shared across tumor regions in any of the patients, while over 94% of T‐cell clones were restricted to individual tumor regions. The Morisita overlap index (MOI) ranged from 0.21 to 0.66 among multi‐regions within the same tumors, significantly lower than that of lung cancer (P = 0.002). Our results show that LP harbored extremely high genomic and TCR ITH and suppressed T‐cell infiltration, suggesting a potential contribution to the frequent recurrence and poor therapeutic response of this adenocarcinoma.

Vibrating flip-flow screens (VFFSs) provide an effective solution for deeply screening moist and fine-grained minerals, and an accurate dynamic model of VFFSs is critical for its dynamic analysis and optimization, thereby improving the vibration stability and symmetry of VFFSs. In this paper, uniaxial tension, uniaxial compression, plane tension, and shear stress relaxation experiments were conducted on screen panel samples to illustrate that the third-order Ogden model and the generalized Maxwell model can accurately describe the hyperelasticity and viscoelasticity of screen panels. Then, the coupling method of finite element and discrete element was adopted to establish the simulation model of the screen panel and material group coupling system, and the dynamics of the coupling system under different loading conditions were explored. Finally, the dynamic model of the coupling system of VFFSs mass, screen panel, and material group was proposed, and the non-dominated sorting genetic algorithm II was applied to optimize the system’s dynamic response. The results reveal that the use of optimized shear springs can reduce the relative amplitude change rate of the main and floating screen frame by 44.30% while maintaining the periodic motion of the VFFSs under operation conditions, greatly enhancing the stability of the VFFSs system.

In the paper, the modulation effect of rotor-stator interaction subjected to fluctuating rotation speed is investigated numerically. A quasi-bivariate variable mode decomposition method for analyzing non-stationary flow fields is proposed for the first time. Different from the previous studies, this paper emphasizes the local features of the transient flow field at fluctuating rotation speed. The results show that the impact of fluctuating rotation speed on the impeller force is limited, but it significantly impacts the pressure pulsation at fluctuating frequency. The correlation between amplitude and fluctuation ratio is positive. Meanwhile, the fluctuating rotation speed also induces sidebands centered on the blade passing frequency and its harmonics. The periodic changes in rotational speed lead to frequency and amplitude modulation of pressure pulsations. The magnitude of the instantaneous frequency and amplitude increases as the fluctuation ratio grows. The change in pressure field is well synchronized with the rotational speed, while the change in velocity field lags behind the rotational speed. The variation of pressure field with rotational speed is mainly attributed to two aspects. One is the flow structure at the fluctuating frequency, and the other is the instantaneous component of the flow structure at blade passing frequency.

The depth understanding of the organic structure characteristics of coal and its evolution is beneficial to the clean and efficient coal directional conversion. This research probes the evolution path and mechanism of carbon structure of lignite during the hydrothermal transitions dewatering (HTD) and tetralin solvent thermal transitions dewatering (TTD). The structural evolution with these two transitions was explored using 13C NMR and XRD in an autoclave at different temperatures. The moisture content in lignite is effectively decreased during HTD and TTD processes, and this is mainly due to the removal of O-containing functional groups and the decrease of water holding capacity. The TTD process is achieved a higher dehydration and deoxidation for lignite compared with HTD process. This is possibly due to that the dehydrating energy of TTD process not only comes from the thermal energy, but also the tetralin is more likely to form hydrogen bonds with water. The aromaticity is increased during HTD and TTD processes, and this increase is possibly contributed by aromatization while the contribution of aromatic rings condensation was limited because the molar ratio of aromatic bridgehead carbon has changed little. Also, from the XRD data, the stacking of aromatic structural units are significantly promoted and are not obvious for the lateral extended size for crystal structural evolution during HTD and TTD processes. when the pretreatment temperature was at 310 °C, the aromaticity increase from 60.94% to 69.50% and 69.68% during HTD and TTD processes, respectively. The stacking height increase from 8.94 Å to 12.06 Å and 13.27 Å, and the stacking number increase from 2.49 to 3.51 and 3.86, the lateral sizes have changed little. The increase of aromaticity is finally manifested in aromatic units vertical stacking height and stacking layer number. These results indicate that the graphitization and ordering are promoted to some degree during HTD and TTD processes. Compared with the HTD, the TTD had the greater impact on the conversion of lignite carbon structure to high-rank coal. Those results are potentially useful to the clean and efficient utilization of lignite.

Segmental testicular infarction is a rare clinical condition most often seen as acute unilateral scrotal pain. Segmental testicular infarction should be suspected in patients with scrotal pain; when an ultrasound shows hypoechoic or mixed echogenic lesions within the testicular parenchyma; contrast-enhanced ultrasound shows a little or no contrast filling, along with negative multiple tumor markers. This report presents a 60-year-old male who presented with sudden onset of left testicular pain with no apparent cause. Emergency Doppler ultrasound, contrast-enhanced ultrasound, and laboratory tests showed findings characteristic of Segmental testicular infarction. The patient the final diagnosis was based on a combination of clinical findings (regression or cessation of symptoms, no tumor marker abnormalities, no palpable testicular mass) and ultrasound evidence of improvement (size reduction or shape change from oval to wedge) during a follow-up period of at least 3 months.

Abstract Two-dimensional high-throughput data have become increasingly common in functional genomics studies, which raises new challenges in data analysis. Here, we introduce a new statistic called Zeta, initially developed to identify global splicing regulators from a two-dimensional RNAi screen, a high-throughput screen coupled with high-throughput functional readouts, and ZetaSuite, a software package to facilitate general application of the Zeta statistics. We compare our approach with existing methods using multiple benchmarked datasets and then demonstrate the broad utility of ZetaSuite in processing public data from large-scale cancer dependency screens and single-cell transcriptomics studies to elucidate novel biological insights.

With the development of the national earthquake intensity quick report and early warning project, more and more “earthquake early warning (EEW)” has come into public view. There are more and more questions about “what is EEW” at home and abroad along with a variety of interpretations of EEW techniques. This paper discusses the progress of earthquake early warning in China, the essence and limitation of EEW. The essence of EEW is that the earthquake observation has entered a new stage of intensive observation, and EEW is the alert for application of earthquake quick report from minutes to seconds. Due to the limitations of early warning blind area and inaccurate estimation of earthquake intensity in the practical application of EEW, the understanding of earthquake scientists on the application efficiency of EEW technology has been deepened and changed. They gradually realized the importance of strengthening the alert function of EEW. At the same time, EEW is a complex social engineering. Scientists need to guide the public to understand the limitations of EEW in order to play the role of disaster reduction effectively.

IRIS is an important international academic research institution in the field of seismology，focusing on seismic observation. It has an important contribution and far-reaching influence on the development of seismology，and its development is highly concerned by seismology scholars from all over the world. The author introduces the strategic plan of IRIS （2016—2020） from the aspects of strategic foundation，strategic implementation，strategic priorities，action items，etc.，aiming to provide a useful reference for scholars who formulate our country’s “14th Five-Year Plan” for earthquake disaster prevention and mitigation plan. These strategic priorities of IRIS are clear and feasible，such as ① maintaining the diversity and advancement of observation facilities；② enhancing the ability to deploy instruments in extreme environments；③ developing new technologies for data reception，processing，storage and service，and providing cutting-edge data management and data processing capabilities for maintaining leading capabilities in data management and applications area. These new technologies include data service technology （Dirt-to Desktop，D2D） ，diversity comprehensive observation and deployment technology，and disaster prediction，hazard assessment and response technology，and intensive seismic observation，high-performance computing and data processing technology；④ promoting and disseminating advanced seismic technology，developing high-level data products；⑤ carrying out diversified academic activities for attracting talents from different fields of scientific research to work at IRIS. These strategic priorities of IRIS are worthy of our study and reference.

Rapid changes in the performance-related parameters of a pump during its startup operation lead to large pressure fluctuations and structural vibrations in it. In view of these problems, this study investigates the evolution of cavitation and the characteristics of fluctuations under pressure in a centrifugal pump during startup. We use the finite volume method to simulate this dynamic process. To characterize the acceleration, we assume that the rotational speed and rate of flow of the pump are not constant but vary with time. A steady-state numerical simulation is performed to examine the external characteristics of the pump to verify the accuracy of the numerical procedure. The evolution of fluctuations in the cavity and pressure over time is then analyzed in detail. We use the short-term Fourier transform for post-processing in light of its advantage in treating non-stationary signals. The results indicate that both the frequency and the amplitude of the fluctuations in pressure increase with the speed of the impeller. The transient operation causes the average pressure at the inlet of the impeller to decrease to the evaporation pressure, and this leads to an increase in the volume fraction of vapor. Moreover, both the impeller–tongue interaction and the impeller–diffuser interaction influence the fluctuations in cavitation.

Summary: Large-scale shale gas exploitation greatly enriches ethane resources, making the oxidative dehydrogenation of ethane to ethylene quite fascinating, but the qualified catalyst with unique combination of enhanced activity/selectivity, enhanced heat transfer, and low pressure drop presents a grand challenge. Herein, a high-performance Nb2O5-NiO/Ni-foam catalyst engineered from nano- to macroscale for this reaction is tailored by finely tuning the performance-relevant Nb2O5-NiO interaction that is strongly dependent on NiO-precursor morphology. Three NiO-precursors of different morphologies (clump, rod, and nanosheet) were directly grown onto Ni-foam followed by Nb2O5 modification to obtain the catalyst products. Notably, the one from the NiO-precursor of nanosheet achieves the highest ethylene yield, in nature, because of markedly diminished unselective oxygen species due to enhanced interaction between Nb2O5 and NiO nanosheet. An advanced catalyst is developed by further thinning the NiO-precursor nanosheet, which achieves 60% conversion with 80% selectivity and is stable for at least 240 h. : Catalysis; Organic Reaction; Nanomaterials; Nanostructure Subject Areas: Catalysis, Organic Reaction, Nanomaterials, Nanostructure

Summary: CO2 circular economy is urgently calling for the effective large-scale CO2 reutilization technologies. The reverse water-gas shift (RWGS) reaction is the most techno-economically viable candidate for dealing with massive-volume CO2 via downstream mature Fischer-Tropsch and methanol syntheses, but the desired groundbreaking catalyst represents a grand challenge. Here, we report the discovery of a nano-intermetallic InNi3C0.5 catalyst, for example, being particularly active, selective, and stable for the RWGS reaction. The InNi3C0.5(111) surface is dominantly exposed and gifted with dual active sites (3Ni-In and 3Ni-C), which in synergy efficiently dissociate CO2 into CO* (on 3Ni-C) and O* (on 3Ni-In). O* can facilely react with 3Ni-C-offered H* to form H2O. Interestingly, CO* is mainly desorbed at and above 400°C, whereas alternatively hydrogenated to CH3OH highly selectively below 300°C. Moreover, this nano-intermetallic can also fully hydrogenate CO-derived dimethyl oxalate to ethylene glycol (commodity chemical) with high selectivity (above 96%) and favorable stability. : Chemical Reaction; Catalysis; Nanomaterials Subject Areas: Chemical Reaction, Catalysis, Nanomaterials

The selfishness and randomness of users in the mobile crowd sensing network could cause them unwilling to participate in sensing activities and lead to lower completion rates of sensing tasks. In order to deal with these problems, this paper proposes a novel incentive mechanism based on a new auction model for mobile crowd sensing, which consists of two consecutive stages. In the first stage, a novel Incentive Method based on Reverse Auction for Location-aware sensing (IMRAL) is proposed to maximize user utility. By introducing a task-centric method to determine the winning bids, it can provide higher user utility and higher task coverage ratio. To ensure the truthfulness of IMRAL, we design a unique payment determination algorithm based on critical payment for the incentive platform. In the second stage, we propose a user-interaction incentive model (UIBIM) to cover the situation that a user may drop out of the sensing activity. This new incentive model includes a dynamic double auction framework prompting users' interaction and a user matching algorithm based on a bipartite graph. The proposed new mechanism achieves the goal of improving task completion rates without increasing the cost of the incentive platform. The simulation results show that comparing with other solutions, such as a truthful auction for location-aware collaborative sensing in mobile crowdsourcing and incentive mechanism for crowdsourcing in the single-requester single-bid-model, IMRAL can achieve better performance in terms of average user utility and tasks coverage ratio, and the UIBIM can significantly improve task completion rates.

In dense Wireless Local Area Networks (WLANs), high-density Access Points (APs) bring severe interference that seriously affects the experience of users, resulting in lower throughput and poor connection quality. Due to the heavy computation workload raised by the sizable networking systems and the difficulty in estimating instantaneous Channel State Information (CSI), existing works are hard to solve interference problem. In this paper, we propose a Joint Power control and Channel allocation based on Reinforcement Learning (JPCRL) algorithm combining with statistical CSI to reduce interference adaptively. Firstly, we analyze the correlation between transmit power and channel, and formulate the interference optimization as a Mixed Integer Nonlinear Programming (MINLP) problem. Secondly, we use the statistical CSI method to take the power and channel state as the state and action space, the overall throughput increment as the reward function of Q-learning, and obtain the optimal joint optimization strategy through off-line training. Moreover, for the periodic reinforcement learning process leading to resource consumption, we design an event-driven mechanism of Q-learning, which triggers online learning to refresh the optimal policy by event-driven condition and the consumption of computing resources can be reduced. The evaluation results show that the proposed algorithm can effectively improve the throughput compared with the existing scheme.

As the sensor layer of Internet of Things (IOT), enormous amount of sensor nodes are densely deployed in a hostile environment to monitor and sense the changes in the physical space. Since sensor nodes are driven with limited power batteries, it is very difficult and expensive for wireless sensor networks (WSNs) to extend network lifetime. In order to achieve reliable data transmission in WSNs, energy efficient routing protocol is a crucial issue in extending the network lifetime of a network. However, traditional routing protocols usually propagate throughout the whole network to discover a reliable route or employ some cluster heads to undertake data transmission for other nodes, which both require large amount energy consumption. In this paper, to maximize the network lifetime of the WSN, we propose a novel energy efficient region source routing protocol (referred to ER-SR). In ER-SR, a distributed energy region algorithm is proposed to select the nodes with high residual energy in the network as source routing node dynamically. Then, the source routing nodes calculate the optimal source routing path for each common node, which enables partial nodes to participate in the routing process and balances the energy consumption of sensor nodes. Furthermore, to minimize the energy consumption of data transmission, we propose an effective distance-based ant colony optimization algorithm to search the global optimal transmission path for each node. Simulation results demonstrate that ER-SR exhibits higher energy efficiency, and has moderate performance improvements on network lifetime, packet delivery ratio, and delivery delay, compared with other routing protocols in WSNs.

Deep dry screening is the key unit in mineral processing. A vibrating flip-flow screen (VFFS) can provide effective solutions for screening fine-grained minerals, and it has been extensively used in many industrial fields. An accurate dynamic model of VFFS considering the influence of materials is significant for its dynamic analysis and screening process research, but it has rarely been studied in detail. In this paper, an improved dynamic model of VFFS is proposed and its dynamic equations are solved to find the reasonable operating condition, and experiments are carried out to verify the reasonability of the proposed model under no-load and loading materials conditions. Furthermore, the method of multistage sampling and multilayer screening is also applied to evaluate the screening performance of iron ore at 3 mm cut size on VFFS. Results show that when the mass of materials, relative amplitude, and operating frequency have values of 107 kg, about 6 mm and 80.79 rad/s, respectively, the screening efficiency gradually increases with an increase of screening length, reaching 89.05%; however, it does not change much when the screening length exceeds 1900.8 mm. Additionally, the misplaced materials of coarse particles will continue to increase as the screening length increases. This provides theoretical and technical support for the optimization of the length of the VFFS.

The seismotectonically induced changes in groundwater radon (Rn) are considered to be strong imputes for the surveillance of imminent major earthquakes. Groundwater facilitates the migration of soil gases as a result of tectonic stresses. In this regard, a radon time series is statistically analysed to identify the radon anomalies possibly induced by Wenchuan earthquake. The statistical analysis mainly involves the deterministic analysis of the Rn data and residual Rn analysis using a criterion x¯±2σ of anomaly selection having a confidence interval of 95%. The deterministic analysis reveals that the Rn time series follows a persistent trend 0.5≤H≤1 which confirms the absence of a chaotic regime. On the other hand, the residual Rn shows a notable upsurge straddling the time of the Wenchuan earthquake in the form of pre- and post earthquake changes at monitoring stations having RE/RD≤0.3. The residual Rn level passes the anomaly selection criterion x¯±2σ and is declared as a tectonically induced Rn anomaly. Contrary to this, the response of distant monitoring stations (RE/RD>0.3) to this particular earthquake further validates the link between Rn and earthquake activity. In a nutshell, the present study highlights the potential implications of earthquake-induced radon anomalies for earthquake prediction research.

Inspired by the concept of software-defined network and network function virtualization, vast virtual networks are generated to isolate and share wireless resources for different network operators. To achieve fine-grained resource control and scheduling among virtual networks (VNs), network performance monitoring is essential. However, due to limitation of hardware, real-time performance monitoring is impossible for a complete virtual network. In this paper, taking advantage of the low-rank characteristic of 90 virtual access points (VAPs) measurement data, we propose an intelligent measurement scheme, namely, adaptive and sequential sampling based on matrix completion (MC), which exploits from the MC to construct the complete data of VN performance from a partial direct monitoring data. First, to construct the initial measurement matrix, we propose a sampling correction model based on dispersion and coverage. Second, a stopping condition for the sequential sampling is introduced, based on the stopping condition, the sampling process for a period can stop without waiting for the matrix reconstruction to reach certain of accuracy level. Finally, the sampled VAPs are determined by referring the backforth completed matrixes' normalized mean absolute error. The experiments show that our approach can achieve a constant network perception and maintain a relatively low error rate with a small sampling rate.

As a promising future Internet architecture, information-centric networking (ICN) takes the content as the focal point while shifting away from the traditional host-centric paradigm. The content-oriented feature and in-network caching from ICN enable new economic or pricing models among Internet service provider (ISP), content provider (CP), and users. The current pricing models in ICN usually focus on that users directly pay the content price to the CP, which leaves the ISPs out of the payment processes, resulting in ISP's reluctance to deploy ICN. Furthermore, the existing models largely ignore the interaction between the pricing strategy and user consumption behaviors, such as choosing cheaper ISPs or giving up the acquisition of the content with high prices. In order to design a collaborative pricing framework to prompt ISP's deploying ICN, we first develop a content acquisition scheme in conjunction with the lump-sum and retail strategies for ICN. Within this scheme, a user consumption model to characterize the user's behaviors in using the Internet and the utility function for all ICN entities, including the CP, access ICN, and transit ICN, are formulated to maximize the revenues of all entities. Our extensive analysis and numerical results show that the proposed collaborative pricing framework significantly outperforms the existing scheme in joint caching and pricing strategies.

To solve the problem of high energy consumption caused by the large initial material pressure of the feeding system, the macroscopic and mesoscopic laws of the effect of the movement of the feeder on the material pressure were studied, and an optimization method of changing the initial position of the feeder to reduce the initial material pressure is proposed. First, the influence of the movement direction of the feeder on the material pressure was studied based on the discrete element method and verified by experiments. A single-factor experiment was designed to analyze the influence of particle size, material repose angle, and bin slope on material pressure, drawing the applicable conditions of the proposed method. On this basis, the influence of the movement state of the feeder on the change of material pressure during the descent process was studied. Then, the motion parameters of the selected feeder descending process were optimized by the response surface method. Finally, case analyses of the vibrating feeding system and the scraper feeding system were carried out. The Discrete Element Method (DEM) calculation results show that the movement of the feeder will cause different distributions and evolution of the force chain on the mesoscale, which will result in different changes in the macroscopic material pressure. The initial material pressure and the material resistance were reduced in the optimized feeding system.

Double-deck vibrating flip-flow screens have been widely used for the repurposing of decoration waste; however, the influence of shear spring stiffness on the screen’s vibration characteristics is under-researched. The shear spring stiffness affects the amplitude–frequency characteristics, phase–frequency characteristics, screening performance and processing capacity of the screen. In this paper, a mathematical model of the double-deck vibrating flip-flow screen is proposed based on a vibrating system with three degrees of freedom. Based on the experiments of the industrial screen, the amplitude–frequency and phase–frequency characteristics of the double-deck vibrating flip-flow screen were studied. Within the range of 25 to 75 rad/s, the amplitude of the main screen frame decreased gradually, the floating screen frames decreased at first and then increased and the amplitudes of the main and floating screen frames were dependent on the stiffness of the isolation springs and shear springs. When the frequency was 75 rad/s, the stiffness of the upper and lower shear springs was 11,440 kN/m, respectively, and the screening efficiency reached 97.09%.

Abstract IEEE 802.11 wireless LAN is proliferating since the increased trend in the wireless network utilization on mobile devices. Accuracy, fast content delivery, and reliable mobility support are essential features of any network to support the changing trend in a wireless network. However, traditional architectures in wireless LAN (WLANs or WiFi) always endured from challenges such as the provision of consistent mobility, real-time packet flow, and seamless handoff. Generally, most of the WLAN only relies on signal strength for handoff which is not sufficient enough for fair selection of an access point (AP) and therefore causes imperfect performance of the network. We present a novel mobility management scheme for WLANs to deal with the mobility management issues, and load balancing by software-defined network (SDN) and network function virtualization (NFV) technologies. The proposed scheme is based on logical AP (LAP) that keeps a connection with the user/mobile terminal (MT) during handoff triggered by either the user or the SDN controller for seamless mobility. It also involves the current state of each AP in addition to traditional parameters of WLAN. We implemented the proposed scheme on a real testbed in a WLAN environment. The evaluation results authenticate that our proposed scheme provides robust handover without throughput degradation and load imbalance among adjacent APs, and allocates the best AP in the neighboring region. Moreover, our proposed scheme is feasible to implement since it did not require any modification at the mobile terminal.

The inflexible management and operation of today's wireless access networks cannot meet the increasingly growing specific requirements, such as high mobility and throughput, service differentiation, and high-level programmability. In this paper, we put forward a novel multipath-transmission supported software-defined wireless network architecture (MP-SDWN), with the aim of achieving seamless handover, throughput enhancement, and flow-level wireless transmission control as well as programmable interfaces. In particular, this research addresses the following issues: 1) for high mobility and throughput, multi-connection virtual access point is proposed to enable multiple transmission paths simultaneously over a set of access points for users and 2) wireless flow transmission rules and programmable interfaces are implemented into mac80211 subsystem to enable service differentiation and flow-level wireless transmission control. Moreover, the efficiency and flexibility of MP-SDWN are demonstrated in the performance evaluations conducted on a 802.11 based-testbed, and the experimental results show that compared to regular WiFi, our proposed MP-SDWN architecture achieves seamless handover and multifold throughput improvement, and supports flow-level wireless transmission control for different applications.

Metals supported on metal oxides are common heterogeneous catalysts. Here the authors show that metal/oxide interfacial sites are highly active for alcohol oxidation—independent of the particle sizes—and use this information to design inverse oxide-on-metal particles with high activity and stability.

The vibrating flip-flow screen (VFFS) is a high-efficiency device currently used for deep screening of moist fine-grained materials. During VFFS operation, the normal operation of the screen is affected by fatigue damage to the shear springs arranged symmetrically on both sides of the screen, leading to equipment failures and disruption production. In this paper, the shear spring’s static and dynamic characteristics in different operation conditions were studied using the INSTRON 8801 fatigue test system and Dynacell dynamic sensors. Using an experimental test of shear spring stiffness and damping coefficients, the effects of some factors, i.e., temperature, hardness, amplitude and frequency, were studied. The results show that the temperature of the shear spring on the left side of the flip-flow screen was higher than that of the right side (driving side). With an increase in temperature, the stiffness of the shear spring decreased. With the increase in amplitude, the dynamic stiffness decreased and the damping coefficients did not change; with the increase in frequency, the dynamic stiffness increased and the damping coefficient decreased. At the same amplitude, with the increase in hardness of the shear spring, the dynamic stiffness increased. Finally, the stiffness and damping coefficients of the shear spring before and after tearing were obviously reduced. These research results reveal the relationship of the characteristics of a shear spring with operational conditions, and could provide a theoretical reference for the design of the VFFS and the selection of the shear spring.

Many recent researches focus on ICN (Information-Centric Network), in which named content becomes the first citizen instead of end-host. In ICN, Named content can be further divided into many small sized chunks, and chunk-based communication has merits over content-based communication. The universal in-network cache is one of the fundamental infrastructures for ICN. In this work, a chunk-level cache mechanism based on pre-fetch operation is proposed. The main idea is that, routers with cache store should pre-fetch and cache the next chunks which may be accessed in the near future according to received requests and cache policy for reducing the users' perceived latency. Two pre-fetch driven modes are present to answer when and how to pre-fetch. The LRU (Least Recently Used) is employed for the cache replacement. Simulation results show that the average user perceived latency and hops can be decreased by employed this cache mechanism based on pre-fetch operation. Furthermore, we also demonstrate that the results are influenced by many factors, such as the cache capacity, Zipf parameters and pre-fetch window size.

The past years have witnessed the significant development of the Internet. Numerous emerging network architectures and protocols have triggered the demand for traffic generators which stand in stark contrast to previous schemes. Namely, fixed test content is inefficient in the presence of such a dynamic and realistic demand. Moreover, the requirement of high-performance has raised the stakes on developing a new concurrent system. In this paper, we present a hierarchical parallel design for a Web traffic generator on a TILERAGX36 processor, called TGMP. We discuss the challenges in developing its hierarchical architectural design, and elaborate on its implementation details. Specifically, in order to generate a realistic network workload over a long and large time scale, we propose a user-control scheme based on cubic spline interpolation. To better improve the scalability of the system and satisfy the required flow rate, we adopt techniques, including optimization of parameters under the Linux kernel, event-driven concurrency, and parallel architectures of a TILERAGX36 processor. The experimental results demonstrate that TGMP is able to create real traffic and simulate 50,000 users accessing the Web server simultaneously.

Hydrogen peroxide (H2O2) is a versatile oxidant, and its eco-friendly synthesis via visible light and air oxygen is crucial. Anthraquinone compounds were employed as homogeneous photocatalysts for alcohol oxidation, yielding H2O2 under visible light. Instead of using traditional catalyst library screening, a model based on density functional theory was proposed to structurally optimize anthraquinone photocatalysts, resulting in the discovery of a novel catalyst significantly boosting H2O2 generation (up to 621.2 mM h-1 intermittently). Continuous flow reactor design improvements can enhance chemical transformation efficiency, as demonstrated by continuous H2O2 production using 2,6-di-tert-butyl anthraquinone. When isopropanol was used as the hydrogen atom donor, H2O2 production rates reached 3950.6 mM h-1 in a 7-minute reaction, with a space--time yield of 7.90 mol (L h) -1, showcasing promising advancements in green H2O2 synthesis. [ABSTRACT FROM AUTHOR]