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As a rising star among porous solid materials, covalent organic frameworks(COFs) with excellent properties including but not limit to facilely controllable structure, high porosity, and multi-chemical functionality represent significant potential for efficient 127Xe/85Kr capture and separation. In this study, through tuning the length of the organic ligands, two-dimensional(2D) COF materials with identical connection group but different pore properties, denoted as ATFG-COF and TpPa-COF with AA-stacking model and TpBD-COF with AB-stacking model were synthesized and tested for Kr and Xe adsorption for the first time. Adsorption measurements indicate that the narrower pore apertures and higher porosity are conducive for COF materials to capture Xe and Kr. Furthermore, the Henry’s constant, isosteric heat of adsorption(Qst), and ideal adsorbed solution theory(IAST) selectivity of ATFG-COF, the pore size of which is closest to the kinetic diameter of the Xe atom(0.41 nm) among 2D COF materials, were carried out based on the single component sorption isotherms. The results illustrate that the high isosteric heat values of Xe/Kr adsorption on ATFG-COF are 25 and 16 kJ/mol at room temperature, respectively. Henry’s law predicts that the selectivity factor of Xe to Kr is 6.07, consistent with the adsorption selectivity(ca. 6) calculated based on the IAST.

Summary The capture of radioiodine species during nuclear fuel reprocessing and nuclear accidents is crucial for nuclear safety, environmental protection, and public health. Previously reported emerging materials for iodine uptake cannot outperform commercial zeolites and active carbon under the practical dynamic scenario. Herein, we present a new design philosophy aiming at significantly enhanced specific host-guest interactions and obtain a nitrogen-rich covalent organic framework material by introducing a bipyridine group into the building block for the simultaneous capture of both iodine gas through enhanced electron-pair effect and organic iodide via the methylation reaction. These efforts give rise to not only an ultrahigh uptake capacity of 6.0 g g−1 for iodine gas and a record-high value of 1.45 g g−1 for methyl iodide under static sorption conditions but also, more importantly, a record-high iodine loading capability under dynamic conditions demonstrated from the breakthrough experiments.

The pleated filter cartridges are widely used in industrial production to control particulate emissions and recover valuable particulate matter, where pulse jet cleaning is a major method for filter regeneration. However, for strong hygroscopic and adhesive dust such as Polyacrylamides (PAM), during pulse-jet cleaning the compressed air forms a low temperature zone at the nozzle and will release water to the environment, causing the particles to adhere on the filter after absorbing moisture, resulting in ineffective filter regeneration. Therefore, a higher cleaning pressure or other methods are required to clean the filter surface. In this article, we have proposed a method to collect adhesive dust using dry gas injection and verified its feasibility through pilot experiments. The compressed air injection source was replaced with nitrogen, the curve of system pressure drop shows that nitrogen has good performance in the peeling of adhesive dust from the surface of the pleated filter cartridge. This highlights the effect of the moisture content in the cleaning compressed air on the regeneration of filters clogged with adhesive hygroscopic particles. Therefore, the feasibility of the nitrogen injection was validated, which provides a basis for the future systematic research of industry to collect adhesive dust.

Advanced oxidation processes (AOPs) present one of the most promising strategies to deal with the ever-growing water pollution. However, fabricating improved catalysts with large size (meter level or larger), long-term stability, and adequate activity is still a formidable challenge in practical applications. In this study, cobalt ions are covalently linked on the polypropylene nonwoven fabric (P-PFeCo) via irradiation graft polymerization and used as highly efficient and stable reaction sites to degrade highly toxic and difficult biodegradable organics by activating peroxymonosulfate (PMS). The presence of graft chains not only generates a well-defined monometallic reaction microenvironment, but also promotes electron transfer. The as-prepared catalyst combines these exceptional properties for efficient removal of dyes or antibiotics via activating PMS within 8 min and exhibits remarkable durability over a wide pH range and recyclability after five consecutive runs with trace cobalt leaching. The X-ray absorption fine structure (XAFS) spectroscopy and density functional theory (DFT) calculations reveal that the CoN4(H2O)2 site acts as an active site for activating PMS. A device in a flow mode is also constructed to illustrate the potential applications of P-PFeCo. We consider that the catalytic process along with the large-sized substrate will broaden a new horizon in terms of designing high-performance catalysts for PMS activation in wastewater treatment.

Disk I/O is the major performance bottleneck of existing out-of-core graph processing systems. We found that the total I/O amount can be reduced by loading more vertices into memory every time. Although task partitioning of a graph processing system is traditionally considered equivalent to the graph partition problem, this assumption is untrue for many Machine Learning and Data Mining (MLDM) problems: instead of a single value, a vector of data elements is defined as the property for each vertex/edge. By dividing each vertex into multiple sub-vertices, more vertices can be loaded into memory every time, leading to less amount of disk I/O. To explore this new opportunity, we propose a category of 3-D partitioning algorithm that considers the hidden dimension to partition the property vector. The 3-D partitioning algorithm provides a new tradeoff to reduce communication costs, which is adaptive to both distributed and out-of-core scenarios. Based on it, we build a distributed graph processing system Cube and an out-of-core system SingleCube . Since network traffic is significantly reduced, Cube outperforms state-of-the-art graph-parallel system PowerLyra by up to $4.7\times$ 4 . 7 × . By largely reducing the disk I/O amount, the performance of SingleCube is significantly better than state-of-the-art out-of-core system GridGraph (up to $4.5\times$ 4 . 5 × ).

Waste printed circuit boards (WPCBs) contain certain amounts of valuable metals such as gold, and so recycling the gold from WPCBs is necessary. Based on our previous study, gold can be selectively...

Removal of 99TcO4− from legacy defense nuclear tank waste at Savannah River Site is highly desirable for the purpose of nuclear safety and environmental protection, but currently not achievable given the extreme conditions including high alkalinity, high ionic strength, and strong radiation field. Herein, we present a potential solution to this long-term issue by developing a two-dimensional cationic metal organic framework SCU-103, showing ultrahigh stability in alkaline aqueous media and great resistance to both β and γ radiation. More importantly, it is very effective for 99TcO4− separation from aqueous media as demonstrated by fast exchange kinetics, high sorption capacity, and superior selectivity, leading to the successful removal of 99TcO4− from actual Savannah River Site high level tank waste for the first time, to the best of our knowledge. In addition, the uptake mechanism is comprehensively elucidated by molecular dynamics simulation and density functional theory calculation, showing a unique chemical recognition of anions with low charge density., Separation of 99TcO4− from nuclear waste at the Savannah River Site is hampered by the extreme conditions. Here, the authors propose a solution by developing an alkaline-resistant metal organic framework material featuring unique recognition sites for selective incorporation of 99TcO4− anions.

A new technique is proposed for the in situ printing of fluorescent fabrics with superior fluorescent properties that have the potential for continuous roll-to-roll production in the industry. Nonconjugated chemical moieties were covalently connected to polyethylene/polypropylene nonwoven fabric (PE/PP NWF) to successfully prepare fluorescent PE/PP NWF, which emits a bright blue light and has a high quantum yield (∼83.35%) that can be attributed to a unique aggregation-induced emission effect. The fluorescent PE/PP NWF exhibits excellent fluorescent stability under high shear forces during accelerated laundering and in harsh chemical environments. The fluorescent PE/PP NWF can also be tailored into diverse shapes and printed in situ with high resolution. The versatility of the method was also demonstrated by fabricating fluorescent materials with different polymer matrices such as Nylon 66 fiber and PE terephthalate membrane.

Immobilization of photocatalysts on substrates is an important factor for water purification in practical applications. In this study, an efficient Ag@AgBr photocatalytic coating was attached onto the surface of cotton fabric via radiation-induced graft polymerization and subsequent chemical reactions, and the resultant product was denoted as Cot-Ag@AgBr. The graft chains acted not only as a source of bromine, but also as an intermediate layer to anchor the Ag@AgBr photocatalytic coating via strong electrostatic interactions. The immobilized Ag@AgBr photocatalytic coating exhibited outstanding photocatalytic properties for organic dye degradation under visible light irradiation. Furthermore, Cot-Ag@AgBr presented high stability and robust durability, which conferred its excellent visible-light-driven photocatalytic activity after five rounds of photodegradation. After 10 min of ultrasonication, the amount of Ag@AgBr precipitate that leached from the Cot-Ag@AgBr was

Molecular deposition (MD) filming flooding has proved to be an effective enhanced oil recovery (EOR) method in reservoirs where recovery was relatively difficult. The B425 block with a low permeabi...

In this work, the electronic excited states of hypoxanthine in solution such as water and acetonitrile are investigated by the time-dependent density functional theory (TDDFT) method. We demonstrated for the first time that the intermolecular excited-state electron transfer (ESET) from solvents to the hypoxanthine through excited-state intermolecular hydrogen-bonds cluster exhibits obvious site-selectivity. Excited-state electron transfer could only occur at the N7 site of hypoxanthine molecule in water solution, while that is the N9 site in acetonitrile. Potential energy surfaces for different electronic states of hypoxanthine with and without the influence of the excited-state hydrogen bonding cluster are also discussed. Site-selective ESET is proposed to induce the internal conversion of hypoxanthine from S2 state to S1 at a conical intersection, which is responsible for the ultrashort lifetime of hypoxanthine in excited state in solution. These results pave a novel way to understand the photophysical and photochemical behaviors of DNA bases and their derivatives in solution phase.

Textiles with fire detection will appeal for the interior decoration of houses and play a critical role in public security. Herein, we fabricated a sandwichlike fire alarm fabric (Ag@Fe3O4-MS) base...

Alkyl-PAHs are the predominant form of PAHs in crude oils which are supposed to demonstrate different toxicities compared to non-alkyl PAHs. Little information is available about the toxicity of alkyl-PAHs on marine Artemia. This study addressed and compared the lethal, behavioral, growth and developmental toxicities of three alkyl-PAHs, namely 3-methyl phenanthrene (3-mPhe), retene (Ret) and 2-methyl anthracene (2-mAnt), to their non-alkyl forms, phenanthrene (Phe) and anthracene (Ant) using Artemia parthenogenetica (nauplii

A bifunctional interfacial layer was introduced onto the surface of cotton fabric which not only enhanced the interfacial bonding between Ag@ZnO and organic substrates but also improved the photocatalytic performance simultaneously. In detail, a modified cotton fabric (denoted as Cot-g-Si/Ag@ZnO) was fabricated through radiation-induced graft polymerization of γ-methacryloxypropyl trimethoxysilane and followed the in-situ formation of ZnO and loading of Ag nanoparticles simultaneously. Owing to ZnOSi between the graft chains and Ag@ZnO photocatalyst, the charge carrier concentration increased and Ag was prevented from oxidizing through the partial separation from ZnO, leading to enhanced near-field amplitudes of the localized surface plasmon resonance. Cot-g-Si/Ag@ZnO also exhibited excellent photocorrosion resistance, photostability and laundering durability. Its photocatalytic activity was fully maintained after several photodegradation cycles; moreover, after laundering durability test, the photocatalytic activity was improved compared with the newly prepared one. Credible mechanism for the photocatalytic activity of Cot-g-Si/Ag@ZnO under sunlight irradiation is proposed.

Remote Direct Memory Access (RDMA) devices are widely deployed in modern data centers. However, existing RDMA usages lead to a dilemma between performance and redesign cost. Server-reply mode directly replaces socket-based send/receive primitives with corresponding RDMA counterparts. It can not fully harness the power of RDMA devices. Server-bypass is distinct mode provided by RDMA for reaching the hardware limits. This mode can totally bypass the server by using one-sided RDMA operations but at the cost of redesigning software. This paper provides a different approach, called RF-RPC (Remote Fetching RPC Paradigm). Different from server-reply, RF-RPC makes client fetch the results from server using one-sided RDMA instead of waiting the results pushed by server. Different from server-bypass, RF-RPC demands server to process client's requests for supporting programming paradigm like RPC. Thus, RF-RPC can achieve high performance without abandoning traditional programming models. An RF-RPC supported in-memory key-value store shows that the performance can be improved by 1.6× comparing to server-reply paradigm and 4× comparing to server-bypass paradigm.

The convective heat transfer of the plume of a 120-N thruster is investigated experimentally and numerically. Numerical results agree well with experimental results in that there is a nonlinear decrease in convective heat transfer with an increasing cone angle. It is also found that convective heat transfer decreases with increasing distance from the thruster outlet. Furthermore, the convective heat transfer of the plume mainly concentrates within a 35° cone angle and the heat flux decreases to the same order as solar radiation at the Earth’s surface when the cone angle exceeds 60°. The results of the study will help improve spacecraft design.

Maximum likelihood (ML) method for direction of arrival (DOA) estimation achieves an excellent performance in array signal processing, but the complexity and computational load of searching the multidimensional nonlinear function prevented it from practical application. Based on squirrel search algorithm (SSA), an improved SSA (ISSA) for ML DOA estimation is proposed in this paper, which can reduces the computational complexity. The idea of spatial variation and diffuse inspired by the invasive weed optimization(IWO) algorithm is applied to ISSA. The simulation experiments compared ISSA with SSA, IWO, seeker optimization algorithm(SOA), sine cosine algorithm (SCA), genetic algorithm (GA), particle swarm optimization (PSO) and differential evolution (DE) method for ML DOA estimator show that the proposed algorithm has faster convergence speed, fewer iterations and lower root mean square error(RMSE) under different number of signal sources, different signal to noise ratio(SNR) and different population size. Therefor the proposed algorithm does not only ensure the estimation accuracy, but also greatly reduce the computation complexity of multidimensional nonlinear optimization for the ML method. Finally, the test experiment using Micro Electronic Mechanical Systems(MEMS) vector hydrophone array in Fenhe lake show the engineering practicability of proposed ML DOA estimator with ISSA.The results obtained will be valuable in the application of engineering.

A new kind of highly durable, electrically conductive UHMWPE fibers coated with copper was fabricated through a novel, simple, and universal process in this paper. Poly(acrylic acid) was anchored o...

The byte-addressable non-volatile memory (NVM) is a promising technology since it simultaneously provides DRAM-like performance, disk-like capacity, and persistency. The current NVM deployment with byte-addressability is \em symmetric, where NVM devices are directly attached to servers. Due to the higher density, NVM provides much larger capacity and should be shared among servers. Unfortunately, in the symmetric setting, the availability of NVM devices is affected by the specific machine it is attached to. High availability can be achieved by replicating data to NVM on a remote machine. However, it requires full replication of data structure in local memory --- limiting the size of the working set. This paper rethinks NVM deployment and makes a case for the \em asymmetric byte-addressable non-volatile memory architecture, which decouples servers from persistent data storage. In the proposed \em \anvm architecture, NVM devices (i.e., back-end nodes) can be shared by multiple servers (i.e., front-end nodes) and provide recoverable persistent data structures. The asymmetric architecture, which follows the industry trend of \em resource disaggregation, is made possible due to the high-performance network (e.g., RDMA). At the same time, \anvm leads to a number of key problems such as, still relatively long network latency, persistency bottleneck, and simple interface of the back-end NVM nodes. We build \em \anvm framework based on \anvm architecture that implements: 1) high performance persistent data structure update; 2) NVM data management; 3) concurrency control; and 4) crash-consistency and replication. The key idea to remove persistency bottleneck is the use of \em operation log that reduces stall time due to RDMA writes and enables efficient batching and caching in front-end nodes. To evaluate performance, we construct eight widely used data structures and two transaction applications based on \anvm framework. In a 10-node cluster equipped with real NVM devices, results show that \anvm achieves similar or better performance compared to the best possible symmetric architecture while enjoying the benefits of disaggregation. We found the speedup brought by the proposed optimizations is drastic, --- 5$\sim$12× among all benchmarks.

The in situ growth of one-dimensional magnetite (Fe3O4) nanowire (NW) arrays with deterministic and tunable control over their orientation and morphology on a wide range of flexible and low heat resistance substrates is still a challenge. Herein, a facile method of controlling the orientation of Fe3O4 NW arrays on a polypropylene (PP) nonwoven fabric surface (PP-g-PAO/Fe3O4) through simultaneous radiation induced graft polymerization and coprecipitation processes was realized. We demonstrated a control over the orientation and geometric properties of coprecipitated Fe3O4 NWs via complex iron ion using amidoxime groups, which not only endow the material with high durability but also lead to the oriented growth of Fe3O4 NWs. The results showed that Fe3O4 NWs were only grown on the surface of the PP nonwoven fabric (length:diameter ratio ≈ 10), whereas the Fe3O4 produced in the solution exhibited a spherical structure under identical conditions. The PP-g-PAO/Fe3O4 composite presented a good saturated magneti...

A new approach of finely tuning multinuclear clusters of metal–organic frameworks (MOFs) through symmetry-upgradingly isoreticular transformation was first presented and a bcu-type MOF, {[Cu4(μ4-O)Cl2(IN)4][CuCl2]}∞ (NJU-Bai35; NJU-Bai for Nanjing University Bai group), with cluster [Cu4(μ4-O)Cl2(COO)4N4] of higher symmetry compared to the pristine MOF, was successfully synthesized. The symmetry upgrading implemented on the inorganic part triggers the adjustment of channels in NJU-Bai35 to fit CO2 molecules, leading to a high CO2 adsorption capacity (7.20 wt % at ∼0.15 bar and 298 K) and high selectivity of CO2 over N2 and CH4 (275.8 for CO2/N2 and 11.6 for CO2/CH4) in NJU-Bai35. Breakthrough experiments further confirmed that NJU-Bai35 might be an excellent candidate for CO2 capture and natural gas purification.

This work investigated the amounts of dust residual of a rectangular flat pleated filter for collecting corn straw particles during pulse cleaning and attempted to explore the causes of incomplete cleaning. In this study, dust residual, filter’s pressure drops and static peak pressures were obtained across flat pleated filter during the pulse cleaning. The optimum parameters were obtained that the pulse electromagnetic valve size was one inch, the pulse pressure was 0.2–0.3 MPa, and the filtration velocity was 0.6 m/min for the nozzle type with 7 holes with a diameter of 7 mm (7 × Ф7 mm). Under this condition, the experimental results show that the dust residuals were 198.4 (64%), 52.7 (17%), 58.9 (19%) g for initial collected dust residual 310 g at top, middle and bottom areas of the filter panel, respectively. The dust residuals were major on the top area of the filter panel, especially on the gap locations between the two-adjacent pulse airflows. Meanwhile, the more pulse interval or dust concentration was increased the dust residuals of the filter panel and the pressure drops of the filter were increased. Moreover, the static peak pressure distribution can give guidance to the dust residual distribution.

Self-resonating cavitation waterjets (SRCW) offer the advantages of both cavitation jets and pulsed jets, and thus have been used in a broad array of practical and industrial applications. Pressure oscillations in the SRCW chamber are closely related to the resonating mechanism and the cavitation inception, and experiments focusing on the chamber pressure were conducted under various pressure drops and inspiratory methods. Hilbert-Huang transform (HHT) combined with empirical mode decomposition (EMD) were able to filter the undesired signals and provide a better frequency definition. Based on the experimental results, the bubble cluster accounts for the energy fluctuation and should be considered in frequency prediction. A modified model was proposed based on the combination of fluidic networks and the Gas-Spring Theory and in accordance with the frequency variation under various pressure drops. When air was introduced, the frequency characteristics is attributed to the unsteady motion of the mixture flow, in which the water and the bubble cluster appeared alternately.

In this work, the time-dependent density functional theory (TDDFT) method was performed to investigate the electronic spectra and charge transfer in excited states of firefly luciferin anion (NRO - ) in aqueous solution. A novel electronic spectral blue-shift (usually red-shift) phenomenon of NRO - was observed due to the significant influence of intermolecular hydrogen bonds between firefly luciferin anion and water molecules. We theoretically demonstrated that the excited-state intermolecular hydrogen bond weakening is confirmed by the increase of hydrogen bond length and decrease of hydrogen bond binding energy from our optimized ground-state and excited-state geometric conformations of the hydrogen-bonded NRO - –H 2 O complex. The hydrogen bond weakening behavior could also be indicated by photoinduced charge transfer from the carboxyl group to the planar part of NRO - in the excited state. Furthermore, we pointed out that the electronic spectral blue-shift should be ascribed to the intermolecular hydrogen bond weakening in this electronic excited state. The weakened hydrogen bonding interaction in the excited state would induce smaller downshift for the excited-state energy level than that for ground-state energy level. As a result, the energy gap between the excited state and ground state becomes larger, which means that the spectral peak corresponding to the electronic excited state will shift to the blue induced by the excited-state hydrogen bond weakening dynamics.

An innovative ultrahigh molecular weight polyethylene (UHMWPE) fibrous adsorbent was successfully synthesized via radiation grafting and applied to the selective capture of palladium ions from dilute aqueous solutions. The influence of the pH, initial Pd(II) concentration, and temperature on the adsorption performance was examined in a batch adsorption experiment. Pd K-edge extended X-ray absorption fine structure (EXAFS) spectra indicated that Pd(II) was immobilized on the adsorbent surface via a ligand exchange reaction that formed a stable UHMWPE-PMDA-Pd complex. Although the concentrations of coexisting ions (Cu(II), Zn(II), Cr(VI), Fe(III), and Ni(II)) in the solution were much higher than that of Pd(II), the adsorption capacity for Pd(II) of the as-prepared absorbent was significantly greater than that for other metal ions. Kinetic studies showed good correlation with the pseudo-second-order model. The maximum capacity for Pd(II) adsorption was approximately 221.8 mg·g −1 at 298 K. The adsorption behavior conformed to the Langmuir isotherm model. Thermodynamic studies revealed that the adsorption of Pd(II) was a feasible, spontaneous, and endothermic process.

Emerging non-volatile memory (NVM) offers non-volatility, byte-addressability, and fast access at the same time. It is suggested that programs should access NVM directly through CPU load and store instructions. To guarantee crash consistency, durable transactions are regarded as a common choice of applications for accessing persistent memory data. However, existing durable transaction systems employ either undo logging , which requires a fence for every memory write, or redo logging , which requires intercepting all memory reads within transactions. Both approaches incur significant overhead. This article presents D ude T x , a crash-consistent durable transaction system that avoids the drawbacks of both undo and redo logging. D ude T x uses shadow DRAM to decouple the execution of a durable transaction into three fully asynchronous steps. The advantage is that only minimal fences and no memory read instrumentation are required. This design enables an out-of-the-box concurrency control mechanism, transactional memory or fine-grained locks, to be used as an independent component. The evaluation results show that D ude T x adds durability to a software transactional memory system with only 7.4%--24.6% throughput degradation. Compared to typical existing durable transaction systems, D ude T x provides 1.7× --4.4× higher throughput. Moreover, D ude T x can be implemented with hardware transactional memory or lock-based concurrency control, leading to a further 1.7× and 3.3× speedup, respectively.

Low-salinity water (LSW) flooding has become a quite simple, effective, and economically feasible enhanced oil recovery (EOR) technology under the background of low oil price. The B425 block with a low permeability in Shengli oilfield, China, has achieved an excellent LSW flooding performance, but the main EOR mechanisms in the block are still not clear. Therefore, in order to investigate the LSW flooding mechanisms in the B425 block, a set of core-flooding experiments were conducted. The water contact angle on core slice and the zeta potential of rock particle were also measured. Then the main EOR mechanisms of LSW flooding in the block were discussed. The experimental results show that the LSW injection can indeed enhance the oil recovery in the low-permeability oil reservoir. Compared with the direct high salinity water (HSW) injection, direct LSW injection and HSW–MSW (medium salinity water)–LSW successive injection can increase the oil recovery factor by 10% and 29.52%, respectively (when the core pe...

Self-sustained oscillations resulting from a sudden expansion in geometry, as encountered in cavities, occur in a broad array of engineering applications. In the present study, the turbulent flow past a 120°-impinging edge Helmholtz nozzle was investigated. A modified theoretical model accompanied by numerical simulation was proposed to obtain the range of the oscillation frequency and was verified using experimental results. It was found that the cavitation clouds in the chamber dominate the oscillating frequency under the low pressure-high flowrate condition. Based on the simulation results, the details of cavitation development, the motion of vortex structures, and the fluid injection and reinjection were investigated in one typical cycle. The interaction between the cavitation and the vortex formation was analyzed with the vortex transport equation. The dilatation term, which is related to the mass transfer rate through the linkage of velocity divergence, has a high value only around the bulk flow; while the baroclinic torque is predominant due to the unremitting collapse and coalescence of the cavitation clouds.

A blend of isotactic polypropylene (PP) with high-density polyethylene (HDPE) in different PP/HDPE ratios was irradiated by γ-ray to induce cross-linking and then foamed using supercritical carbon dioxide (scCO 2 ) as a blowing agent. Radiation effect on the melting point and crystallinity were analyzed in detail. The average cell diameter and cell density were compared for PP/HDPE foams prepared under different conditions. The optimum absorbed dose for the scCO 2 foaming of PP/HDPE in terms of foaming ability and cell structure was 20 kGy. Tensile measurements showed that the elongation at break and tensile strength at break of the crosslinked PP/HDPE foams were higher than the non-crosslinked ones. Of particular interest was the increase in the foaming temperature window from 4 ℃ for pristine PP to 8–12 ℃ for the radiation crosslinked PP/HDPE blends. This implies much easier handling of scCO 2 foaming of crosslinked PP with the addition of HDPE.

A highly effective antimicrobial nylon 66 fiber doped with permanganate ions was prepared via a simultaneous irradiation induced graft polymerization. The physicochemical properties of the fibers were carefully characterized by various techniques, including Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy, revealing that permanganate ions (about 1.48 mmol/g) have been successfully loaded onto the surface of the nylon 66 fibers. The antimicrobial activity of the modified nylon 66 fibers against Staphylococcus aureus and Candida albicans were investigated. Accelerated laundering tests and tensile tests were conducted to access the effect of laundering on the antimicrobial activity and the mechanical property of the modified nylon 66 fibers, respectively. All results indicate that we have prepared a new highly effective antimicrobial nylon 66 fiber (almost a 100% reduction in the number of S. aureus and C. albicans colonies). Furthermore, the modified nylon 66 fibers are durable, maintaining antimicrobial resistance after 100 commercial or domestic launderings and retaining its excellent mechanical property during preparation and laundering.

In this work, the excited-state intermolecular hydrogen bonding interactions, photoinduced charge transfer, and vibrational spectroscopic properties of deprotonated deoxyadenosine monophosphate [dAMP-H]− anion in aqueous solution were investigated by the DFT/TDDFT method. The intermolecular hydrogen-bonded model complexes [dAMP-H]−–nH2O (n = 0, 1, 2, 3, 4) in both the ground state and electronic excited state were first discussed. Analysis of frontier molecular orbitals reveals an intramolecular charge transfer (ICT) state for [dAMP-H]−–nH2O (n = 0, 1, 2) complexes in which charge transfer occurs from the phosphate group to the base. However, it becomes a locally excited (LE) state for [dAMP-H]−–nH2O (n = 3, 4) complexes, which only locates on the adenine moiety. The excited energies of the first excited state of [dAMP-H]−–nH2O (n = 0, 1, 2, 3) increase gradually during the introduction of water molecules, but decreases with the fourth water molecule at adenine site. The fourth water molecule has little influence on the structure but significant to the photoexcitation. Upon electronic excitation, stretching vibration frequencies of N H and O H of hydrogen bonds: N5 H10 ⋯ O9, O9 H19 ⋯ O10 and O10 H21 ⋯ O3 are red-shifted. The excited-state bond lengths of these hydrogen bonds are also shortened. Therefore, the total intermolecular hydrogen bonding interaction at the base moiety is significantly strengthened in the electronic excited state.

The halogen-substituted derivatives and the parent aniline tetramer as organic semiconductors have been theoretically investigated with a focus on the electronic properties and charge transport properties through density functional theory and Marcus–Hush theory methods. The study on the transport properties of holes and electrons can obtain insight into the effect of halogenation substitution on injection of charge carriers and transport character. The equilibrium geometries, reorganization energies, frontier molecular orbitals, intermolecular electronic couplings, electrostatic potential isosurfaces, and angular resolution anisotropic mobilities were calculated. The calculated results revealed that perfluorination and perchlorination can induce stronger structure relaxation and effectively lower the highest occupied molecular orbital and lowest unoccupied molecular orbital levels. The angle dependence mobilities of the three crystals show remarkable anisotropic character. The carrier mobility curves for ...

We present a crystal engineering strategy to fine tune the pore chemistry and CH4-storage performance of a family of isomorphic MOFs based upon PCN-14. These MOFs exhibit similar pore size, pore surface, and surface area (around 3000 m2 g−1) and were prepared with the goal to enhance CH4 working capacity. [Cu2(L2)(H2O)2]n (NJU-Bai 41: NJU-Bai for Nanjing University Bai's group), [Cu2(L3)(H2O)2]n (NJU-Bai 42), and [Cu2(L4)(DMF)2]n (NJU-Bai 43) were prepared and we observed that the CH4 volumetric working capacity and volumetric uptake values are influenced by subtle changes in structure and chemistry. In particular, the CH4 working capacity of NJU-Bai 43 reaches 198 cm3 (STP: 273.15 K, 1 atm) cm−3 at 298 K and 65 bar, which is amongst the highest reported for MOFs under these conditions and is much higher than the corresponding value for PCN-14 (157 cm3 (STP) cm−3).

Many distributed graph processing frameworks have emerged for helping doing large scale data analysis for many applications including social network and data mining. The existing frameworks usually focus on the system scalability without consideration of local computing performance. We have observed two locality issues which greatly influence the local computing performance in existing systems. One is the locality of the data associated with each vertex/edge. The data are often considered as a logical undividable unit and put into continuous memory. However, it is quite common that for some computing steps, only some portions of data (called as some properties) are needed. The current data layout incurs large amount of interleaved memory access. The other issue is their execution engine applies computation at a granularity of vertex. Making optimization for the locality of source vertex of each edge will often hurt the locality of target vertex or vice versa. We have built a distributed graph processing framework called Photon to address the above issues. Photon employs Property View to store the same type of property for all vertices and edges together. This will improve the locality while doing computation with a portion of properties. Photon also employs an edge-centric execution engine with Hilbert-Order that improve the locality during computation. We have evaluated Photon with five graph applications using five real-world graphs and compared it with four existing systems. The results show that Property View and edge-centric execution design improve graph processing by 2.4X.

Atactic polypropylene (PP) samples with melt flow indices (MFI) of 7.0 g/10 min were irradiated and then foamed with supercritical carbon dioxide (scCO2). A detailed investigation was carried out to understand the effect of radiation on the scCO2 foaming of polypropylene. Variations in the molecular weight, branching degree, crystallinity, and melting and crystallization temperatures of irradiated PP were investigated. The cell diameter, cell density, volume expansion ratio and foaming rate were analyzed in detail under different conditions. It was found that the cell structure of PP foam became more uniform and the foaming temperature window increased to 10 °C. This compares favorably to the 4 °C observed with pristine atactic PP. The best cell morphology was observed at a dose of 30 kGy. The corresponding average diameter and cell density were 16.4 μ m and 5.7×107 cells/cm3, respectively.

A novel fibrous adsorbent containing amine and quaternary ammonium groups was prepared by radiation-induced graft of glycidyl methacrylate (GMA) onto ultra-high molecular weight polyethylene (UHMWPE) fiber and further modifying with triethylenetetramine (TETA) and glycidyl trimethylammonium chloride (GTA). The ATR-IR spectra and SEM observation demonstrated that amine and quaternary ammonium groups were immobilized onto the surface of UHMWPE fiber. The principal factors affecting the adsorption of Cr(VI) ions have been investigated including pH of the aqueous solution, contact time, temperature and coexisting anions. This novel fibrous adsorbent could effectively adsorb Cr(VI) in the range of pH 1–9, and the maximum adsorption capacity reached 295 mg/g at pH 3 and 25 °C based on the Langmuir isotherm. It was found that adsorption equilibrium could be achieved within 2 h for initial Cr(VI) of 100 mg/L, following the pseudo-second order model. The effect of coexisting anions (including SO42−, H2PO4−, NO3−and Cl−) on the uptake of Cr(VI) was investigated in detail. Additionally, the adsorption saturated fiber could be regenerated by soaking in 0.5 mol/L NaOH solution, and the adsorption performance of this adsorbent could be maintained at 90% after eight cycles of adsorption-desorption. ATR-IR and XPS analysis revealed that Cr(VI) ions were adsorbed on the fiber adsorbent through ion exchange mechanism.

Herein, the promotion effects of thionation and isomerization on the carrier mobility properties of naphthalene diimide and thionated naphthalene diimide crystals were investigated in detail based on the Marcus-Hush theory and quantum-chemical calculations. The thionation of NDIs will improve the charge mobility of both electrons and holes, which is similar to the thionation of PDIs. The compound P only behaves as an n-type organic semiconductor (OSC), whereas the three other thionation structures have higher mobility values and can behave as p-type OSCs. For the cis/trans isomers of the two double-thionation structures, trans-S2 has a larger hole and electron carrier mobility than cis-S2; this is consistent with the experimental results obtained for cis-trans-isomers. A potential strategy for the development of high performance ambipolar OSCs is the substitution of O atoms by S atoms. These results will provide a guide for the design and optimization of OSCs via analysis of the relationship between carrier mobility and molecular crystal structures.

Along with the fast development of society, the demand for energy continually increases. Shale gas, a type of unconventional natural gas trapped within shale formations, is considered to be one of the best clean alternative fuels with the most potential because of large reserves all over the world. However, hydraulic fracturing, a widely used technology in shale gas exploitation, may cause serious environment issues. Therefore, the application of supercritical carbon dioxide (SC-CO 2 ) instead of water to fracture shale has been mentioned. This novel approach could enhance shale gas recovery with no harm to the environment. To investigate the use of a SC-CO 2 jet on the wellbore pressure and temperature, a series of experiments based on impinging theory have been conducted in the present study. In the first experiment, a specially designed apparatus with four visual windows was used to intuitively observe the jet's structure and character with a high speed video system recording the entire experimental process. In the second experiment, a high precision sensor was assembled in the vessel to measure the impinging pressure. The result shows that: (1) a SC-CO 2 jet has a similar structure as a water jet, while a SC-CO 2 jet dissipates slowly due to its low viscosity; (2) the impinging pressure increases with the increasing jet pressure, but the increasing rate is different because dissipation ratio decreases; (3) the ambient pressure affects the jet energy transfer rate though flow resistance and the ambient density. Under present experimental conditions, the critical pressure is 14.5 MPa; (4) a predictive equation is listed to calculate the impinging pressure based on the jet pressure and ambient pressure. Considering the application, the minimum jet pressure should be chosen to be more than 1.5 times the ambient pressure, and a suitable target distance for a SC-CO 2 jet is no more than 7.5 nozzle diameters. These results help optimize the parameters of the SC-CO 2 jet and promote the application of SC-CO 2 in shale gas exploitation.

Random walk on graphs has recently gained immense popularity as a tool for graph data analytics and machine learning. Currently, random walk algorithms are developed as individual implementations and suffer significant performance and scalability problems, especially with the dynamic nature of sophisticated walk strategies. We present KnightKing, the first general-purpose, distributed graph random walk engine. To address the unique interaction between a static graph and many dynamic walkers, it adopts an intuitive walker-centric computation model. The corresponding programming model allows users to easily specify existing or new random walk algorithms, facilitated by a new unified edge transition probability definition that applies across popular known algorithms. With KnightKing, these diverse algorithms benefit from its common distributed random walk execution engine, centered around an innovative rejection-based sampling mechanism that dramatically reduces the cost of higher-order random walk algorithms. Our evaluation confirms that KnightKing brings up to 4 orders of magnitude improvement in executing algorithms that currently can only be afforded with approximation solutions on large graphs.

Processing-In-Memory (PIM) architectures based on recent technology advances (e.g., Hybrid Memory Cube) demonstrate great potential for graph processing. However, existing solutions did not address the key challenge of graph processing---irregular data movements. This paper proposes GraphQ, an improved PIM-based graph processing architecture over recent architecture Tesseract, that fundamentally eliminates irregular data movements. GraphQ is inspired by ideas from distributed graph processing and irregular applications to enable static and structured communication with runtime and architecture co-design. Specifically, GraphQ realizes: 1) batched and overlapped inter-cube communication by reordering vertex processing order; 2) streamlined inter-cube communication by using heterogeneous cores for different access types. Moreover, to tackle the discrepancy between inter-cube and inter-node bandwidth, we propose a hybrid execution model that performs additional local computation during the inter-node communication. This model is general enough and applicable to asynchronous iterative algorithms that can tolerate bounded stale values. Putting all together, GraphQ simultaneously maximizes intra-cube, inter-cube, and inter-node communication throughput. In a zSim-based simulator with five real-world graphs and four algorithms, GraphQ achieves on average 3.3× and maximum 13.9× speedup, 81% energy saving compared with Tesseract. We show that increasing memory size in PIM also proportionally increases compute capability: a 4-node GraphQ achieves 98.34× speedup compared with a single node with the same memory size and conventional memory hierarchy.

The partial-period autocorrelation of sequences is an important performance measure of communication systems employing them, but it is notoriously difficult to be analyzed. In this paper, we propose an algorithm to design unimodular sequences with low partial-period autocorrelations via directly minimizing the partial-period integrated sidelobe level (PISL). The proposed algorithm is inspired by the monotonic minimizer for integrated sidelobe level (MISL) algorithm. Numerical experiments show that the proposed algorithm can effectively generate sequences with lower partial-period peak sidelobe level (PPSL) than the well-known Zadoff-Chu sequences.

Bacterial biofilm segmentation poses significant challenges due to lack of apparent structure, poor imaging resolution, limited contrast between conterminous cells and high density of cells that overlap. Although there exist bacterial segmentation algorithms in the existing art, they fail to delineate cells in dense biofilms, especially in 3D imaging scenarios in which the cells are growing and subdividing in a complex manner. A graph-based data clustering method, LCuts, is presented with the application on bacterial cell segmentation. By constructing a weighted graph with node features in locations and principal orientations, the proposed method can automatically classify and detect differently oriented aggregations of linear structures (represent by bacteria in the application). The method assists in the assessment of several facets, such as bacterium tracking, cluster growth, and mapping of migration patterns of bacterial biofilms. Quantitative and qualitative measures for 2D data demonstrate the superiority of proposed method over the state of the art. Preliminary 3D results exhibit reliable classification of the cells with 97% accuracy., v1: Submitted to IEEE International Conference on Image Processing (ICIP) 2019; v2: Minor edits, updated reference and co-authors; v3: Accepted to be published in 2019 IEEE International Conference on Image Processing, Sep 22-25, 2019, Taipei. IEEE Copyright notice added. Minor changes for camera-ready version. (updated May. 6, 2019)

The production of industrial process is the key factor of evaluating the national industry production level. Therefore, this paper proposes total factor productivity analysis method based on Malmquist model to analyze the production efficiency statically and dynamically. Based on the input and output data of ethylene production plants in China, the total factor production index of ethylene production plants in industrial processes is decomposed into technical efficiency, technical progress, pure technical efficiency and scale efficiency through the Malmquist model based on the data envelopment analysis (DEA). Moreover, the energy efficiency of ethylene production plants can be improved.

Industrial oily wastewater with dye-pollution is a critical environmental issue for water purification. However, the fabrication of effective and stable materials for oil-water separation and simultaneous degradation of organic contaminants remains a critical challenge. Herein, we report a new process for in-situ formation of akaganeite (β-FeOOH) nanorods layer on the surface of poly(ethylene terephthalate) (PET) fabric via radiation-induced graft polymerization of glycidyl methacrylate, which is then sulfonated and mineralized. The resultant product is labeled as β-FeOOH@PET, which exhibits dual purification by demonstrating an effective oil-water separation and organic dyes photodegradation under the illumination of visible light. It provides stable performance even after 1000 wash cycles. The sulfonated layer acts as not only an electronic transport layer to prevent electron-hole recombination, but also as an anchored interface for immobilizing β-FeOOH nanorods on the sulfonated layer via strong covalent bonds. Overall, the superhydrophilicity and underwater superoleophobicity of β-FeOOH@PET fabric, along with its robustness with a flexible organic substrate and its dual purification function, provide a new insight toward oily wastewater remediation and water purification in large-scale applications.

Microplastics are a ubiquitous contaminant of marine ecosystems that have received considerable global attention. The effects of microplastic ingestion on some marine biota have been evaluated, but the uptake, elimination, and histopathological impacts of microplastics remain under-investigated especially for zooplankton larvae. Here, we show that 10 μm polystyrene microspheres can be ingested and egested by Artemia parthenogenetica larvae, which impact their health. The results indicate that A. parthenogenetica larvae have a varying capacity to consume 10 μm polystyrene microspheres that is dependent on microplastic exposure concentrations, exposure times, and the availability of food. The lowest level of microplastics that was ingested by A. parthenogenetica was 0.15 particles/individual when exposed to 10 particles/mL and 0.05 particles/individual when exposed to 1 particle/mL over 24 h and 14 d, respectively. A. parthenogenetica larvae were able to egest feces with microplastics within 3 h of ingestion. However, ingested microplastics persisted in individuals for up to 14 days. Furthermore, microalgal feeding was significantly reduced by 27.2% in the presence of 102 particles/mL microplastics over 24 h. Histological analyses indicated that a greater abundance of lipid droplets was present among epithelia after 24 h of exposure at a concentration of 10 particles/mL. Moreover, intestinal epithelia were deformed and disorderedly arranged after 14 d of exposure. Overall, these results indicate that marine microplastic pollution could pose a threat to A. parthenogenetica health, especially that of larvae. Consequently, further research is required to evaluate the potential physiological and histopathological effects of microplastics for other marine invertebrate species.

In this paper, the errors of acoustic vector sensor array are classified, the impact factor of each error for the array signal model is derived, and the influence of each type of error on the direction-of-arrival (DOA) estimation performance of the array is compared by Monte Carlo experiments. Converting the directional error and location error to amplitude and phase errors, the optimization model and error self-calibration algorithm for acoustic vector sensor array are proposed. The simulation experiments and field experiment data processing of MEMS vector sensor array show that the proposed self-calibration algorithm has good parameter estimation performance and certain engineering practicability.

3D single-molecule localization microscopy relies on fitting the shape of point-spread-functions (PSFs) recorded on a wide-field detector. However, optical aberrations distort those shapes, which compromise the accuracy and precision of single-molecule localization microscopy. Here we employ a computational phase retrieval based on a vectorial PSF model to quantify the spatially-variance of optical aberrations in a two-channel ultrawide-field single-molecule localization microscope. The use of a spatially-variant PSF model enables accurate and precise emitter localization in x, y- and z- directions throughout the entire field-of-view.

Short-term load forecasting in power grids is a necessary part of designing larger power systems and its accuracy can affect real-time control and security functions. So, this paper proposes a new method, which have better performance by using cluster analysis. For the purposed of reducing the redundancy of the training samples and making the training more targeted, this paper proposes the PSO-AFCM clustering algorithm to select similar days. We use an adaptive function that can determine the number of clusters, and optimize the adaptive FCM clustering algorithm with PSO to avoid falling into local convergence. Therefore, the PSO-AFCM clustering algorithm can improve the accuracy of clustering and make the selection of similar days more precise. Finally, the LMBP-Elman-LSSVM combined prediction model is used for load forecasting. The example shows that the proposed method improves the prediction performance and improves the accuracy of load prediction by comparing with the traditional LMBP neural network, Elman neural network and LSSVM.

LiCoO2 is still the most extensively used cathode material in Li-ion battery for portable electronics currently. The increasing usage of electronics has resulted in the growing discard of LiCoO2 with the stream of its spent battery. Current recycling approaches for LiCoO2 from spent batteries are dominantly based on hydrometallurgy and pyrometallurgy, which usually require multiple complicated steps and involve the use of high temperature or harmful chemicals, like acids and alkalis. There remains an urgent need for green and simple processes. Here we report a single step approach based on suspension electrolysis to directly recycle LiCoO2 in one reactor at atmospheric condition without any usage of acid and alkalis. The electrolyte of the suspension electrolysis system is only comprised of NH4HCO3, [Formula: see text] and NaF. The reaction system of LiCoO2 leaching in the anode region and simultaneously re-synthesizing in the cathode region in the electrochemical system is established. Mechanism analysis indicates that NH4+ only serves as a provider for complexing agent of NH3 and is virtually not consumed. This work provides potentially meaningful strategies for recovering LiCoO2 in a shorter procedure and an environmentally friendly manner.

Elemental alloying has been demonstrated to be an effective method to improve the strength of additively manufactured Ti-6Al-4V alloys by inhibiting the formation of coarse columnar primary β grains. However, it is still a challenge to obtain a high-strength titanium alloy with high plasticity. To balance the strength and plasticity, TiB whiskers with cyclic gradient distribution were synthesized in situ as the reinforcement phase in Ti-6Al-4V alloy fabricated by wire arc additive manufacturing (WAAM) based on cold metal transfer (CMT) technology. The ultimate tensile strength of the deposited Ti-6Al-4V alloy with 0.05 wt% boron addition reached 1089 MPa, which was 17% higher than that of directly deposited Ti-6Al-4V alloy, and the elongation remained at 8% without significant reduction. The synergistic balance of strength and ductility was attributed to the grain refinement and cyclic gradient distribution of TiB whiskers. When the boron content was 0.15 wt%, the elongation of the deposited alloy was reduced to 5.2% though tensile strength reached 1178 MPa due to the formation of quasi-continuous TiB whiskers distributed along the prior β grain boundaries. Furthermore, the formation of heat-affected bands between the two adjacent layers of TiB-reinforced Ti-6Al-4V alloy was discussed based on the measurement of the thermal history during the additive manufacturing process and the part’s microstructure evolution.