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In the past years, the issues of energy efficiency and interference are becoming increasingly serious in wireless local area network (WLAN) since lots of access points (AP) are deployed densely to provide high-speed users access. However, current works focus on solving the two issues separately and the influence of each other is rarely considered. To address these problems, we propose a joint optimization scheme of energy efficiency and interference to reduce energy consumption and interference together without sacrificing users’ traffic demands. Firstly, based on energy consumption measurement of AP and network interference analysis, we establish energy efficiency and interference models respectively. Then, the weighting method is introduced to build the joint optimization to quantify the effects of user-AP association, AP switch, AP transmit power and AP channel on energy consumption and interference. Lastly, we formulate the joint optimization as an Mixed Integer Non-Linear Programming (MINLP) problem. Since the MINLP problem is NP-hard, we proposed an Joint Optimization of Energy Efficiency and Interference (JOEI) algorithm based on greedy method to simplify its computational complexity. The evaluation results show that the proposed algorithm can effectively reduce the network energy consumption while improve the capacity of WLANs.

© 2019 John Wiley & Sons, Ltd. The high-bandwidth demands from variety of applications drive a dense wireless local access network (WLAN), which results in a complicated wireless network scene with serious co-channel interference and energy waste. In this paper, to reveal the interactions between interference and energy efficiency, we propose an interference-energy efficiency (IFEE) model to quantify the interference impact on the energy efficiency of 802.11 access point (AP) devices. Firstly, we introduce the channel separation and the difference of received signal strength indication (D-RSSI) as two indicators to extend the classical signal to interference plus noise ratio (SINR) notion and rate adaptive mechanism. Then, these two parameters are integrated into the energy consumption model to establish the IFEE model. Lastly, we conduct extensive measurements with five typical WiFi interference scene in real network to validate the effectiveness of our model. The comparisons between simulation results and real data demonstrate that the proposed IFEE model can quantify the interference and energy efficiency with high accuracy, which can be used for wireless network optimization and protocol design.

Thin-felt NiO-Al2O3/FeCrAl-fiber catalysts engineered from micro- to macro-scales are developed for the high-throughput catalytic oxy-methane reforming to syngas. Crystallization-driven self-assembly process is used to prepare an Al(OH)3/FeCrAl-fiber support (15 wt% Al(OH)3). NiO of ~ 3 wt% is then highly dispersed onto above support via incipient wetness impregnation method followed by a calcination treatment. Such catalyst achieves a high CH4 conversion of 88.6% with 90.7%/93.2% selectivity to H2/CO at 700 °C and a high gas hourly space velocity of 80 L g− 1 h− 1, and is stable for at least 30 h without carbon deposit but a slight sintering. In contrast, a reference catalyst of NiO/FeCrAl-fiber shows a fast deactivation within only 6 h.

© 2018 Elsevier Ltd Aiming to exploit the power of multiple accesses from ubiquitous wireless networks, researchers employed multiple virtualized interfaces connecting to multiple APs for mobile users. However, these schemes require expensive modifications and additional cost on mobile device, which are hard to be implemented. Complementarily, in this paper, we propose a multi-connection virtual access point (MC-VAP) to virtualize and manipulate physical APs to provide multi-path transmission for a user while avoiding any modifications on the user side. As a result, the independent flows from an application can be dispatched to multiple paths separately and transmitted on multiple APs simultaneously, which can improve the throughput obviously. In order to maximize each application's throughput, the flow assignment is formulated as a mixed integer non-linear programming (MINLP) problem. In particular, a low-complexity heuristic algorithm, namely, narrowing search set with cutting-off solution space (NS-CoS) algorithm, is presented to solve the MINLP problem through relaxing it into simple LP problems. Moreover, we implement a prototype of MC-VAP, and the extensive real-world experiments demonstrate that MC-VAP can realize seamless handover and provide faster yet efficient solutions of flow assignment in contrast to the optimal method to achieve multifold throughput improvement for applications over regular WiFi.

Deep dry screening is the key unit in mineral processing. A vibrating flip-flow screen (VFFS) with elastic sieve mats has been widely used for screening fine-grained minerals due to its good performance. The stability of the VFFŚs dynamic response largely affects its screening efficiency and processing capacity, however, it has rarely been investigated in detail. In this paper, aiming at reducing the effect of loading-material for dynamic system through properly operated parameters, stability regions were defined, and for the given working conditions, using performance criteria to evaluate the vibration stability. This was done by theoretical modeling and experimental analysis for the VFFS system. The VFFS can operate in different regions by regulating the shear spring characteristics and the eccentric mass moment. The dynamic response curves were measured and analyzed under different operating conditions; and then, material-loading experiments were carried out to verify the stability of VFFS; furthermore, the method of multistage sampling and multilayer was used to analyze the screening performance of material under three conditions. Results indicated that loading material on VFFS affected its vibration stability and therefore the screening performance. The dynamic response of VFFS was more stable in the near anti-resonance region (a certain distance to the left of anti-resonance frequency) than the other two operating conditions, thus, was not obviously affected by loading material. Screening efficiency for 3 mm material was up to 89.05% with a corresponding total misplaced material of 7.96%.

A monolithic silicon carbide foam (SiC-foam) structured nickel and lanthanum oxide (Ni-La2O3) nanocomposite catalyst is developed via reducing the nickel oxide and lanthanum oxide (NiO-La2O3) precursor that can be grown onto SiC-foam surface by depositing the needed citric acid gel followed by calcination at 750 °C. By taking the advantages of homogeneous component-distribution and strong Ni-La2O3 interactions in the Ni-La2O3 nanocomposites, this catalyst delivers much enhanced coke-depositing/Ni-sintering resistance than the unmodified counterpart of Ni-La2O3/alumina (Al2O3) in the titled reaction. At 850 °C, a weight hourly space velocity (WSHV) is set as 24,000 mLCH4-CO2 gCat−1 h−1, methane/carbon dioxide (CH4/CO2) conversions of 71/85% are initially achieved on the Ni-La2O3/SiC-foam catalyst followed by progressively decreased to 60/72% within 50 h (h), but remain almost unchanged for the next 50 h. On the contrary, the CH4/CO2 conversions on the Ni-La2O3/Al2O3 catalyst rapidly drop from 49/71% to 24/40% within only 25 h due to its serious Ni-sintering and coke deposition.

Although based on lignite pyrolysis poly-generation technology has become an important research direction, how to increase the yield of pyrolysis tar and decrease the yield of pyrolysis water was still a challenge, and the pretreatment of lignite was essential. Here, we designed a combined process of hydrothermal and swelling pretreatment. Combined with the 13C NMR, thermogravimetric and FT-IR analysis, the effect of combined process on pyrolysis products evolution were investigated. The results showed that the combined process was an effective means to improve quality of lignite and increase the yield of pyrolysis tar. The content of moisture decreased from 27.73% of raw coal to 3.7% when hydrothermal treated temperature was at 310 °C. The oxygen-containing functional groups were effectively removed during the hydrothermal process. Compared with the raw coal and coal sample directly swollen from raw coal, the yield of pyrolysis tar for the coal samples of the combined process at 250 °C reached 10.89%, increased by 47.56% and 34.28%, and the pyrolysis water yield for the coal samples of the combined process at 310 °C decreased to 6.20%, falling by 21.12% and 14.11%. The kinetic analysis of raw coal, hydrothermal treated coal and the swelling treated coal was calculated, and found that the activity energy increased after hydrothermal treatment, and decreased the pyrolysis reactivity. However, the activity energy significantly decreased after swelling process, and improve the pyrolysis reactivity.

A Ni-foam-structured PdNi nanoalloy catalyst engineered from nano- to macro-scales has been successfully fabricated for the catalytic deoxygenation of coalbed methane (CBM). The catalyst was obtainable by embedment of Pd nanoparticles onto Ni-foam substrate via a galvanic exchange reaction method and subsequent in situ activation in the reaction, which was active at low temperature, selective (no CO formation), and oscillation free in this CH4-rich catalytic combustion process. Special Pd@NiO (Pd nanoparticles partially wrapped by tiny NiO fragments) ensembles were formed in the galvanic deposition stage and could merely be transformed into PdNi nanoalloys in the real reaction stream at elevated temperatures (e.g., 450 °C or higher). Density functional theory (DFT) calculations were carried out to reveal the role of Ni decoration at Pd in PdNi nanoalloy catalyst for the CBM deoxygenation. By nature, the Pd–Ni alloying modified the electronic structure of surface Pd and led to a decrease in the O adsorptio...

A high-performance PdNi(alloy)/Ni-foam catalyst to be used for coalbed methane (CBM) deoxygenation via catalytic combustion was developed with the aid of galvanic deposition of Pd nanoparticles onto the monolithic Ni-foam followed by in-situ reaction-induced Pd-Ni alloying. The investigations concerning the preparation/reaction conditions and heat/mass transfer indicated that such PdNi(alloy)/Ni-foam catalyst provided a unique combination of high low-temperature activity/selectivity, oscillation-free, high permeability and enhanced heat transfer. As an example, the catalyst with a low Pd-loading of 1 wt% could deliver a complete O 2 conversion for a simulated feed of CH 4 /O 2 /N 2 (40/3/57, vol%) at 350 °C with a high gas hourly space velocity of 12,000 mL g cat. −1 h −1 , and particularly, this catalyst was stable for at least 500 h without deactivation and reaction oscillation. In-situ reaction-induced Pd-Ni alloying was clearly revealed and by nature was responsible for the low-temperature activity (expressed by turnover frequency) promotion and oscillation suppression. The underlying mechanism for CBM deoxygenation over the PdNi(alloy)/Ni-foam catalyst is proposed to be a Langmuir-Hinshelwood type.

Thin-sheet microfibrous-structured Al-fiber@ns-AlOOH@Pd catalysts with low Pd-loading engineered from micro- to macro-scale are developed for the gas-phase CO coupling to dimethyl oxalate, providing unique combination of high activity/selectivity and good stability with high permeability and high thermal conductivity. The support of Al-fiber@ns-AlOOH is initially prepared via endogenous growth of boehmite nanosheets (ns-AlOOH) on 3D network of 60-μm Al-fiber. The palladium is then placed onto the surface of the ns-AlOOH rooted on the Al-fiber via incipient wetness impregnation method with a toluene solution of palladium acetate. As an example, the catalyst with a low Pd-loading of 0.25 wt% delivers ∼66% CO conversion and ∼94% DMO selectivity for a feed of CH 3 ONO/CO/N 2 (10/14/76, vol%) with a gas hourly space velocity of 3000 L kg −1 h −1 , and particularly, is stable for at least 200 h without deactivation. Our Al-fiber@ns-AlOOH@Pd catalyst demonstrates two times higher intrinsic activity (expressed by turnover frequency) compared to a traditional Pd/α-Al 2 O 3 . The existence of Pd-hydroxyl synergistic interaction is paramount to the enhanced catalytic performance for the CO coupling reaction, by nature, as the result of hydroxyl-promoted adsorption of bridged CO on the Pd surface.

Free-standing NiO–MgO composite nanosheet catalysts to be used for catalytic oxy-methane reforming (COMR) have been developed by in-situ growing onto the Ni-foam struts under hydrothermal condition followed by calcination treatment. Among them, the NiO–MgO/Ni-foam consisting of 1.0% MgO, 18.7% NiO and nickel-foam-strut balance is the best structured catalyst engineered from nano- to macro-scale, being capable of converting 82.9% CH4 into syngas at selectivity of 94.7% to H2 and of 89.9% to CO for a feed of CH4/O2=2/1 (vol/vol), at 700 °C and a high gas hourly space velocity of 100 L g−1 h−1. Nevertheless, improvement of their carbon resistance and textural stability is particularly desirable.

For the methanol-to-propylene process, a lumped kinetic model was developed on the basis of dual-cycle reaction mechanism, which attempted to reflect the main reaction paths with a combination to show the evolution of mole fraction of individual light olefins ( C 2 , C 3 and C 4 ) with space time. The experiments were performed in a continuous flow fixed-bed reactor at 0.1 MPa as well as varied reaction temperature from 400 to 480 °C and space time from 0.3 to 32.0 gcatalyst h mol−1, and the experimental data obtained on the structured SS-fiber@HZSM-5 and powdered HZSM-5 catalysts were fitted by MATLAB software based on the established model. The fitted results show that the lumped kinetic model well describes the product distribution and is identified to be suitable by model identification. Compared to the powdered HZSM-5, the SS-fiber@HZSM-5 shows higher diffusion efficiency and narrower residence time distribution, not only promoting the propylene formation but also improving the utilization efficiency of the structured HZSM-5.

Structured Pd–Au–CuOx/Cu-fiber obtainable by a galvanic co-deposition method is post-modified by La2O3 and consequently shows promising low-temperature activity and stability for the titled reaction, due to the in situ formation of a La2O3–PdAu(alloy)–Cu nanocomposite in the reaction thereby leading to enhanced ability for H2 activation and H-spillover associated with the La2O3-assisted activation of CO and C–O groups of dimethyl oxalate.

Promising microfibrous-structured Al-fiber@ns-Al2O3@Fe–Mn–K catalysts are developed for the mass/heat-transfer limited Fischer–Tropsch synthesis of light olefins. The Al-fiber@ns-Al2O3 core–shell composites, engineered on the nano- to macro-scale, are first prepared by endogenously growing thin shell (∼0.5 μm) nanosheet γ-Al2O3 (ns-Al2O3) onto the 3-dimentional microfibrous-structured network consisting of 10 vol% 60 μm Al-fiber and 90 vol% voidage. After modification by K through an impregnation method, the Al-fiber@ns-Al2O3 composites are functionalized with nano-structured Fe and Mn active components via a surface impregnation combustion method. The effect of combustion atmospheres (air, N2, and N2 followed by air (N2–air)) on the catalyst performance is investigated. The as-burnt catalyst obtained under air delivers the highest iron time yield of 206.0 μmolCO gFe−1 s−1 at 89.6% CO conversion with 42.1%C selectivity to C2–C4 olefins (350 °C, 4.0 MPa, 10 000 mL (g−1 h−1)), while the other two as-burnt catalysts under N2 and N2–air yield relatively low CO conversions of 58–67%. Combustion under air is helpful to form 6 nm Fe–Mn–K oxide particles with better reducibility and carbonization properties thereby leading to high performance. In contrast, under either N2 or N2–air atmosphere, smaller oxide particles (3–4 nm) are formed but suffer from deteriorated reducibility and carbonization properties due to the strong support–metal interaction. Such as-burnt catalysts obtained under air also demonstrate promising stability.

A self-supported SS-fiber@meso-HZSM-5 core–shell catalyst was essentially designed and engineered from micro- to macro-scale by caramel-assistant hydrothermal synthesis. The significant role of caramel during the crystallization process was revealed in detail. Caramel not only created the mesoporosity in the ZSM-5 crystals, but also released acid under hydrothermal synthesis conditions which lowered the zeolite crystallinity. By taking advantage of the mesopore development in a hierarchical micro–meso–macropore structure with favourably-tuned acidic properties, such a catalyst provided a dramatically prolonged lifetime of 845 h (>90% conv.) with high propylene selectivity (e.g., 48%) in the MTP reaction. The hierarchical pore structure development mainly increased the accommodation capacity of the zeolite shell for receiving formed coke thereby leading to a dramatically prolonged lifetime in the MTP reaction.

Production of substitute natural gas (SNG) by methanation of syngas generated from various carbon sources provides a promising route towards coal clean utilization and sustainable energy future. Monolithic Ni (or Cu, NiCu-alloy)-foam-structured Ni–Al2O3 catalysts were developed by a facile modified wet chemical etching method. The as-prepared catalysts were characterized by X-ray diffraction, scanning electron microscopy, inductively coupled plasma atomic emission spectrometry and H2-temperature programmed reduction. Among these catalysts, Ni–Al2O3/Ni-foam has the most surface active Ni atoms and exhibits the best catalytic methanation performance, achieving 99.9% CO conversion with 90.0% methane selectivity and being stable for at least 1000 h for a feed gas of H2/CO (3/1) at 330 °C and gas hourly space velocity (GHSV) of 5000 h−1. Effects of reaction temperature, reaction pressure and GHSV are also investigated on the catalytic performance of Ni–Al2O3/Ni-foam for CO methanation. Computational fluid dynamics calculation and experimental measurement consistently show that such monolithic Ni–Al2O3/Ni-foam can dramatically reduce the “hotspot” temperature due to its high thermal conductivity. Moreover, the feasibility of our Ni–Al2O3/Ni-foam catalyst for co-methanation of a simulated feed gas from coal gasification is studied as well as CO2 methanation in the presence of high CH4 concentration. We anticipate that our present work might stimulate commercial exploitation of the new-generation structured catalyst and reactor technology for the strongly exothermic syngas methanation toward energy-efficient process for SNG production.

Catalytic distillation (CD) offers a unique integration of distillation and catalysis to selectively separate products in situ while making a positive shift of chemical equilibrium and has therefore been well received as an inviting avenue to green chemical processing. Rendering novel structured catalytic packings is particularly desirable but remains challenging. Herein, we present a microfibrous-structured Nafion–SiO2/SS-fiber solid acid catalyst and demonstrate its separation and reaction efficiency as CD packings for esterification to produce ethyl acetate from acetic acid and ethanol. A thin-sheet microfibrous structure with 15 vol% 20 μm stainless steel fibers (SS-fiber) and 85 vol% void volume was shaped into θ-ring analogues. Nafion was then firmly locked into the SiO2 layer that was anchored onto the SS-fiber surface by a dip-coating method using self-crosslinking Nafion–SiO2 sol–gel prepared by Nafion-catalyzed hydrolysis of tetraethylorthosilicate (TEOS). Such micro-structured Nafion catalysts worked effectively and efficiently in the CD for esterification of acetic acid with ethanol as the result of a unique combination of high catalyst performance (stability, adequate acidic sites and high mass/heat transfer) and instantaneous distillation. For instance, high total (93.6%) and actual (91.6%) yields of ethyl acetate with 96.2% purity were achievable at a high space-time yield (4.3 g mmol−1 h−1) while the high CD efficiency was maintained for 40 h over 5 consecutive batch runs.

Monolithic microstructured Al-fiber@HZSM-5 core-shell catalysts have been synthesized by directly growing the shell of HZSM-5 with varied SiO 2 /Al 2 O 3 molar ratio on the core of sinter-locked aluminum microfibers. Such monolithic catalysts are examined in the methanol-to-propylene reaction, and the best microstructured catalyst of HZSM-5 with SiO 2 /Al 2 O 3 molar ratio of 200 delivers a C 2 –C 4 selectivity of 62% (~ 36% to C 3 ) as well as a single-run lifetime of 160 h under industrial relevant conditions.

Thin-sheet sinter-locked Ti-microfiber-supported binary-oxide-nanocomposite catalysts engineered on the micro- to macroscales were developed for the gas-phase aerobic oxidation of benzyl alcohol to benzaldehyde. The catalysts demonstrated higher activity than single-oxide and noble-metal catalysts with good stability and regenerability. The catalysts were obtained by placing transient metal (e.g., Ni, Co, Cu, Mn) nitrates onto a Ti-microfiber surface by impregnation, and the supported nitrates were subsequently in situ transformed into the binary-oxide composites in the real reaction stream at 300 °C. Among them, CoO-2.5–CuOx-2.5/Ti-fiber was found to be the best catalyst; it delivered 93.5 % conversion of benzyl alcohol (b.p. 210 °C) with 99.2 % selectivity to benzaldehyde at 230 °C. In situ induced formation of “CoO@Cu2O” ensembles (i.e., larger CoO nanoparticles partially covered with smaller Cu2O clusters and/or nanoparticles) was identified, which by nature resulted in a large Cu2O–CoO interface and led to a significant improvement in the low-temperature activity.

Although poly-generation technology based on lignite pyrolysis has become an important research direction, how to increase the yield of pyrolysis tar and decrease the yield of pyrolysis water is still a challenge, and the pretreatment of lignite is essential. Here, we proposed to improve the quality of lignite though hydrothermal treatment dewatering (HTD) and then change the pyrolysis products distribution. A series of HTD and pyrolysis experiments as well as measurements of lignite and HTD samples were conducted in this paper, and the results indicated that HTD is an effective means to improve the quality of lignite. The moisture (air dried basis) decreased from 26.55% to 5.27% and O/C atomic ratio reduced from 0.26 to 0.17 as the temperature increased to 310 °C. The atomic ratio of H/C increase from 0.85 to 0.90 of HTD-250 and decrease subsequently. HTD caused great changes in its physical and chemical structure, promoting the conversion of aliphatic structural unit to the aromatic structure followed by aromatization of this organic structure, and thus increased coal rank for HTD samples. The pyrolysis tar yield increased from 7.27% of raw coal to 8.49% of HTD-250 and subsequently decreased. The yield of CO2 components and pyrolysis water continued to decrease as the temperature increased, and the amount of decrease reached 24.9% and 39.5%, respectively. The degree of cross-linking reaction of upgraded coal is lower that of raw coal, leading to a reduction in the yield of pyrolysis water and an increase in the yield of tar.

A high-performance Ni-foam-structured FeNi3-FeOx nanocomposite catalyst is developed for the ethanol (EtOH) synthesis from syngas via gas-phase dimethyl oxalate (DMO) hydrogenation. The hydrothermally-synthesized Ni(OH)2/Ni-foam was impregnated with aqueous solution of iron(III) nitrate, from which the preferred FeNi3-FeOx/Ni-foam-(550/350) catalyst was obtainable by calcining preferably at 550 °C (to adequately form NiFe2O4-NiO composites) and subsequently reducing in H2. Such catalyst is capable of fully converting DMO with 98 % ethanol selectivity at 230 °C and 2.5 MPa using a WHSVDMO of 0.44 h−1 and a H2/DMO molar ratio of 90, and particularly, being stable for at least 700 h. A high turnover frequency of 88.8 h−1 is achieved at 180 °C. Exactly, our NiFe2O4-NiO derivation strategy endows the catalyst with plentiful interface between FeNi3 nanoalloy (∼16 nm) and FeOx fragments (acting as acid sites), achieving synergistic catalysis to ester groups in DMO and as-formed hydroxyl groups, thereby markedly improving its hydrogenation to EtOH.

e16518 Background: Gastric linitis plastica (LP) is a rare and aggressive type of gastric cancer (GC) for which the genomic landscape and architecture have gone largely undescribed. Methods: 4 LP patients were enrolled. 10 region tumor samples of each LP patient and matched peripheral blood were collected. Matched blood cells of each patient were also collected for removing germline background Whole-exome sequencing(WES), TCR sequencing, TCGA gastric cancer and several WES articles data were used to investigate intra and inter patient genomic and immune heterogeneity. Results: All 4 LP patients were female and were in stage III. LP biopsies were sequenced with median 290.6x effective depth. A total of 11,504 somatic mutations including 6,339 non-silent mutations were identified. The median non-silent tumor mutation burden (TMB) of biopsy samples was 3.23 mutations/Mb (range from 1.36 to 4.88), which was comparable to gastric adenocarcinoma(p = 0.3). Phylogenetic trees of 4 LP patients demonstrated clear evidence of branched evolution, and the phylogenetic trees varied extensively across the four cases. The percentages of trunk mutations of 4 LP were 12.8%, 5.4%, 5.4% and 30.7%, respectively, while the proportions of trunk neoantigens were 6.2%, 2.2%, 12% and 12.4, respectivelyWhen comparing LP to other multiregion WES studies, e.g., lung adenocarcinoma, renal cell carcinoma, and esophageal squamous cell carcinoma, LP was one of the most heterogeneous tumor types. The top mutational signatures in this cohort associated with spontaneous deamination, DNA mismatch repair (MMR), and small indels at repeats etc. Furthermore, profound TCR ITH was observed in all 4 LP patients. None of the T cell clones were shared among all tumor regions and 94.23-94.41% T cells were restricted to individual tumor regions. To quantify the TCR ITH, we utilized the Morisita overlap index (MOI), which ranged from 0.34 to 0.56 across different regions within the same tumors suggesting marked inter-individual TCR repertoire heterogeneity and profound intratumor TCR heterogeneity. Conclusions: Based on whole-exome sequencing and TCR sequencing, we demonstrate that LP is highly heterogeneous for mutations, neoantigens and T cells, which contributes to its poor prognosis.

In this work, two types of novel photoinitiaors containing phototrigger were prepared to overcome oxygen inhibition in the UV- curing system in the absence of hydrogen donor. The structures of prepared novel photoinitiators were determined by nuclear magnetic resonance (NMR) and high resolution MS (HR MS) spectra data. The photo chemical behavior and photo-reactivity were also evaluated by ultraviolet-visible (UV–vis) spectroscopy and real-time Fourier transform infrared spectroscopy (RT-FTIR), respectively. The results show the prepared photoinitiators exhibit remarkable redshift compared to the commercial BP (benzophenone) and Irgacure 907 (2-methyl-1-(4-methylsulfanylphenyl)-2-morpholin-4-ylpropan-1-one), fast photolysis by C S bond, good photo initiation and significant overcoming oxygen inhibition for some compounds, which can be used as one-component photoinitiator candidates.

Paper mulberry (Broussonetia papyrifera) is a well-known woody tree historically used for Cai Lun papermaking, one of the four great inventions of ancient China. More recently, Paper mulberry has also been used as forage to address the shortage of feedstuff because of its digestible crude fiber and high protein contents. In this study, we obtained a chromosome-scale genome assembly for Paper mulberry using integrated approaches, including Illumina and PacBio sequencing platform as well as Hi-C, optical, and genetic maps. The assembled Paper mulberry genome consists of 386.83 Mb, which is close to the estimated size, and 99.25% (383.93 Mb) of the assembly was assigned to 13 pseudochromosomes. Comparative genomic analysis revealed the expansion and contraction in the flavonoid and lignin biosynthetic gene families, respectively, accounting for the enhanced flavonoid and decreased lignin biosynthesis in Paper mulberry. Moreover, the increased ratio of syringyl-lignin to guaiacyl-lignin in Paper mulberry underscores its suitability for use in medicine, forage, papermaking, and barkcloth making. We also identified the root-associated microbiota of Paper mulberry and found that Pseudomonas and Rhizobia were enriched in its roots and may provide the source of nitrogen for its stems and leaves via symbiotic nitrogen fixation. Collectively, these results suggest that Paper mulberry might have undergone adaptive evolution and recruited nitrogen-fixing microbes to promote growth by enhancing flavonoid production and altering lignin monomer composition. Our study provides significant insights into genetic basis of the usefulness of Paper mulberry in papermaking and barkcloth making, and as forage. These insights will facilitate further domestication and selection as well as industrial utilization of Paper mulberry worldwide.

A thin-sheet Ni-CeAlO3-Al2O3/FeCrAl-fiber to be used in the COMR process was fabricated by thermally decomposing the catalyst precursor of NiAl-LDHs/FeCrAl-fiber to form the NiO-Al2O3/FeCrAl-fiber, followed by CeO2-modification and H2-reduction. Pre-mounting a γ-Al2O3 layer onto the FeCrAl-fiber is particularly critical for the hydrothermal growth of LDHs along with the fiber surface. The most promising catalyst, with 5 wt% Al2O3, 5 wt% Ni, and 2 wt% CeO2, exhibits high activity, high selectivity, and particularly prolonged stability. At a gas hourly space velocity of 100 L g−1 h−1 and 700 °C, CH4 conversion and H2/CO selectivity can be stably maintained at ~86% and ~96.1/~91.5% for a feed gas with CH4/O2 molar ratio of 2.0/1.0 during 350 h test, in nature, due to the enhanced Ni-sintering and improved carbon resistance. The existence of “CeAlO3-CeO2” cycle enables the catalyst with high carbon resistance because of the intensified C-elimination to inhibit filaments growth.

Large-scale shale gas exploitation greatly enriches ethane resources, making the oxidative dehydrogenation of ethane (ODE) to ethylene quite fascinating, but the qualified catalyst presents a grand challenge. A series of Ni-foam-structured MOx-NiO (M = Li, Mg, Ga, Ce, Zr, Mo, W, Nb) composite oxide catalysts (denoted as MOx-NiO/Ni-foam) have been developed for the oxidative dehydrogenation of ethane to ethylene (ODE). The catalysts were obtained by hydrothermal growth of NiC2O4 onto a Ni-foam (110 PPI) and subsequent impregnation with an M-containing salt aqueous solution and calcination treatment. Among them, the Nb2O5–NiO/Ni-foam showed superior catalytic ODE performance over the others. Both Nb2O5 loading and calcination temperature showed remarkable impact on the catalytic performance. The modification with suitable amount of Nb2O5 was responsible for the significant elimination of non-selective oxygen species thereby leading to remarkable improvement of the ethylene selectivity. The activity and selectivity of the Nb2O5–NiO/Ni-foam catalysts are also sensitive to the calcination temperature that can modulate the desorption properties of their lattice oxygen species to a great extent. The most promising Nb2O5–NiO/Ni-foam catalyst is the one modified with 5 wt% Nb2O5 and calcined at 450 °C, being capable of converting 60% ethane with a 68% ethylene selectivity for a feed of C2H6/O2/N2 = 1/1/8 at 410 °C and GHSV of 9000 cm3 g−1 h−1 (corresponding to a high ethylene productivity of 0.423 gC2H4 gcat−1 h−1).

© 2018 IEEE. The demands for high-bandwidth drives a dense wireless local access network (WLAN), which may result in severe co-channel interference and energy consumption increasing. To clearly quantify the effect of interference on energy consumption of 802.11 access devices, it is crucial to measure and model the effect of interference. This paper takes extensive measurements for five different WiFi interference types for downstream UDP transmission in actual environment. Based on experimental measurements, we establish a physical interference-energy efficiency (IFEE) model by reconstructing the signal to interference plus noise ratio (SINR) notion and the modulation and coding scheme (MCS) rate adaptive mechanism to accurately predict the interference impaction. Our experimental measurements demonstrate that interference leads to a decrease in energy efficiency and throughput. Compared with the transmit power, channel separation interference dominates. It is worth noting that the impact of interference with multiple interferers is less than single interferer scene. The simulation experiments verify that our IFEE model can achieve high accuracy of interference and energy efficiency modeling.

This paper aims at defending the data traffic against an attack in Software Defined Networks (SDNs) by leveraging the flexibility to collect traffic information and control traffic routing in SDN. We first model the interaction between an attacker and a defender as a two-player variable sum game model, and analyze the Nash equilibrium of the proposed game model. By further analyzing the Nash equilibrium, we propose some guidelines to control the traffic routing which can help enhance the traffic security under attacking. Based on these guidelines, we design an online algorithm and an offline algorithm to control the traffic routing. By applying our algorithms to the scenario that the attacker intends to destroy a node to break the traffic, our algorithms can greatly reduce the traffic loss when the network is under attacking.

In mobile crowd sensing (MCS), incentive mechanism is one of the most critical issues, and plays an important role on ensuring the quantity of participants and the coverage rate of sensing task. In this paper, we tackle the problem of stimulating enough smartphone users to join in MCS activities with their smartphones. Moreover, the scenario that the selected users drop out of the sensing tasks with random probability during their sensing processes is also taken into account. Therefore, we propose a novel incentive mechanism called IMRAL - an Incentive Mechanism based on Reverse Auction for Location-aware sensing. IMRAL aims to enhance the participants' enthusiasm by maximizing their expected profits. It consists of two parts: winner selection algorithm and payment determination scheme. In the first part, we formulate a winner selection problem by considering the service coverage of mobile users. Due to the NP-hardness of the problem, we introduce a task-centric method to determine the winning bids with polynomial time complexity. The second part is a payment scheme, which determines the payment to winners by a time proportional share rule to ensure the truthful of IMRAL and consider the effects of the randomness of the selected users, and the winners can obtain the maximum utility. Through rigid theoretical analysis, we demonstrate that the proposed mechanism satisfies the properties of computational efficiency, individual rationality, budget feasibility and truthfulness. Simulation results show that, compared with TRAC (truthful auction for location-aware collaborative sensing in mobile crowdsourcing) and IMC-SS (incentive mechanism for crowdsourcing in the single-requester single-bid-model), the IMRAL can achieve better performance in terms of average user utility and tasks coverage ratio.

© 1997-2012 IEEE. Recently, network function virtualization (NFV) has been widely used in 5G innovation. However, with the implementation of NFV, virtualized wireless access point has suffered a significant performance degradation. In this letter, we propose an efficient packet processing scheme (Tuna) to improve the performance of wireless network virtualization. Specifically, we locate management frame into user space for virtualization, and place control and data frame in kernel space to reduce packet processing delay. Moreover, hostapd and network address translation are modified to accelerate packet processing. We implemented the prototype of the proposed scheme, and the experimental results demonstrate that Tuna can improve both delay and throughput dramatically.

© 2013 IEEE. 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 back-forth 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.

A thin-sheet Al-fiber@meso-Al2O3@Fe-Mn-K catalyst is developed for the mass/heat-transfer limited Fischer–Tropsch synthesis to lower olefins (FTO), delivering a high iron time yield of 206.9 µmolCO gFe−1 s−1 at 90% CO conversion with 40% selectivity to C2-C4 olefins under optimal reaction conditions (350°C, 4.0 MPa, 10,000 mL/(g·h)). A microfibrous structure consisting of 10 vol % 60-µm Al-fiber and 90 vol % voidage undergoes a steam-only-oxidation and calcination to create 0.6 µm mesoporous γ-Al2O3 shell along with the Al-fiber core. Active components of Fe and Mn as well as additives (K, Mg, or Zr) are then placed into the pore surface of γ-Al2O3 shell of the Al-fiber@meso-Al2O3 composite by incipient wetness impregnation method. Neither Mg-modified nor Zr-modified structured catalyst yields better FTO results than K-modified one, because of their lower reducibility, poorer carbonization property, and fewer basicity. The favorable heat/mass-transfer characteristics of this new approach are also discussed. © 2015 American Institute of Chemical Engineers AIChE J, 2015

A series of monolithic nickel-foam-structured Ni–MO x (M = Al, Zr or Y) binary catalysts to be used in the catalytic oxy-methane reforming have been developed, of which the Ni–MO x catalysts are formed in-situ and embedded onto the Ni-foam struts by chemically etching Ni-foam using solution containing Al (or Zr, Y) nitrate. Among these catalysts, Ni–Al 2 O 3 /Ni-foam possesses the largest specific surface area and the highest amount of NiO species (i.e., Ni active site precursors), and as a result, exhibits the best catalytic performance with promising stability. Over this catalyst, CH 4 conversion of 86.4% can be obtained with H 2 selectivity of 96.6% and CO selectivity of 91.2% for a fed of CH 4 /O 2 (2/1) at 700 °C and a high gas hourly space velocity of 100 L g − 1 h − 1 . We anticipate our assay to be a new point which might stimulate commercial exploitation of the new-generation structured catalyst technology for the high-throughput catalytic oxy-methane reforming reaction.

Porous Pt-Fe bimetallic nanocrystals have been synthesized via self-assembly and can effectively facilitate the synthesis of 2-propanol from acetone. The bimetallic catalyst has three-dimensional channels and shows turnover frequencies (TOFs) of up to 972 h−1 for a continuous process more than 50 h. Preliminary mechanistic studies suggest that the high reactivity is related to the interface consisting of a bimetallic Pt-Fe alloy and Fe2O3−x . An understanding of real catalytic behavior and the catalytic mechanism based on model systems has been shown to help fabricate an improved Pt/Fe3O4 catalyst with increased activity and lifetime which has great potential for large-scale industrial applications.

Monolithic Ni-Al2O3/Ni-foam catalyst is developed by modified wet chemical etching of Ni-foam, being highly active/selective and stable in strongly exothermic CO2 methanation process. The as-prepared catalysts are characterized by x-ray diffraction scanning electron microscopy, inductively coupled plasma atomic emission spectrometry, and H2-temperature programmed reduction-mass spectrometry. The results indicate that modified wet chemical etching method is working efficiently for one-step creating and firmly embedding NiO-Al2O3 composite catalyst layer (∼2 μm) into the Ni-foam struts. High CO2 conversion of 90% and high CH4 selectivity of >99.9% can be obtained and maintained for a feed of H2/CO2 (molar ratio of 4/1) at 320°C and 0.1 MPa with a gas hourly space velocity of 5000 h−1, throughout entire 1200 h test over 10.2 mL such monolithic catalysts. Computational fluid dynamics calculation and experimental measurement consistently confirm a dramatic reduction of “hotspot” temperature due to enhanced heat transfer. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4323–4331, 2015

Modern society has an ever-increasing demand for environmentally friendly catalytic processes. Catalysis research is working towards a solution through the development of effective heterogeneous catalysts for environment-related applications. Nanotechnologies have provided effective strategies for the preparation of nanocrystals (NCs) with well-defined sizes, shapes and compositions. Precise control of these NCs provides an important foundation for the studies of structure-performance relationships in catalysis, which is critical to the design of NCs with optimized catalytic performances for practical applications. We focus on recent advances in the development of bottom-up strategies to control NCs structures for some key catalytic applications, including CO oxidation, selective oxidation of alcohols, semihydrogenation of alkynes, and selective hydrogenation of unsaturated aldehydes and nitrobenzene. These key applications have been a popular research focus because of their significance in green chemistry. Herein we also discuss the scientific understandings of the active species and active structures of these systems to gain an insight for rational design of efficient catalytic systems for these catalytic reactions.

Concerns about the clean utilization of coal and the development of sustainable energy have provided a particular impetus for the exploration into the production of substitute natural gas (SNG) by syngas methanation in some parts of world. Owing to heat-transfer limitations, current SNG technology based on a series of fixed-bed reactors packed with oxide-supported Ni catalysts suffers from issues such as high costs, low efficiency, and catalyst sintering. We report a monolithic Ni-Ce-Al2O3/Ni-foam catalyst obtainable by modified wet-chemical etching of Ni foam. Such a catalyst, with significantly enhanced heat transfer, is highly active, highly selective, and very stable for syngas methanation. Computational fluid dynamics calculations and experimental measurements consistently show a large reduction in the “hotspot” temperature in the Ni-foam-structured catalyst bed owing to high thermal conductivity. We anticipate that our approach will open a new opportunity for next-generation SNG plant design.

A monolithic Ni-foam@PdNi(alloy) catalyst is tailored for coalbed methane deoxygenation via galvanically depositing Pd nanoparticles on a Ni-foam surface followed by in situ activation. Experimental and theoretical studies unanimously reveal that the in situ formed PdNi alloy contributes to high activity/selectivity, good stability and oscillation elimination.

We report a facile, green and generalized method of endogenous growth of 2D boehmite nanosheets (ns) on a 3D network using Al-fibers through oxidation reaction between the Al metal and H2O (2Al + 4H2O = 2AlOOH + 3H2). Such Al-fiber@ns-AlOOH composites have substantial potential applications for microfibrous-structured catalysts and catalytic reactors, being verified by several hot-topic reactions such as CO oxidative coupling to dimethyl oxalate.

Software-Defined Wireless Network (SDWN) aims to build a flexible wireless network infrastructure that can support future Internet services. In this paper, we present WLAN architecture to take advantage of OpenFlow that provides the global view of the entire network including wireless network configuration, resource allocation, and flow control policies to make the load balanced network environment. We build simulation environment through Mininet-WiFi to analysis throughput and jitter values of associated stations. The results demonstrate that proposed architecture can divide the load between APs that increase the average throughput of associated stations.

Traditional WLAN typically relied on signal strength for handoff that is not sufficient for fair selection of physical access point (PAP) and also causes the poor performance of network and load imbalance. To deal with these issues, we proposed a mobility management scheme on the basis of logical AP (LAP) that keeps a connection with the mobile terminal (MT) during handoff either triggered by the user or software-defined network (SDN) controller for seamless mobility. The proposed scheme was implemented on a real testbed in WLAN environment, and the evaluation results demonstrated that it could provide a rather good seamless handover without throughput degradation and load imbalancing between PAPs, with an efficient handoff procedure to allocate the best AP in the neighbor region.

The purpose of this study is to investigate the safety and 9-month effectiveness of transcatheter left gastric artery embolization (LGAE) for treating patients with obesity. The protocol of this study was approved by the Institutional Ethics Review Board. Five obese patients (3 men and 2 women) with mean weight of 102.0 ± 16.19 kg (range, 82.1–125.5 kg) and mean body mass index (BMI) of 38.1 kg/m2 ± 3.8 (range, 32.9–42.4 kg/m2) underwent LGAE with polyvinyl alcohol (PVA) particles in diameter of 500–710 μm. The primary endpoint was the safety by grading the adverse events (AEs) according to the Common Terminology Criteria for Adverse Events (CTCAE v4.0) within 30 days after LGAE. The secondary endpoints were measured with serum ghrelin and leptin levels, body weight, waist circumference, waist-to-height ratio, and abdominal fat quantity on MRI at the day immediately before LGAE and every 3 months after LGAE. LGAE was successfully performed in all patients. A superficial linear ulceration below the cardia was seen in 1 patient 3 days after LGAE and healed within 30 days. No other serious AEs (grade III or above) occurred. Average body weight loss at 3, 6, and 9 months was 8.28 ± 7.3 kg (p = 0.074), 10.42 ± 8.21 kg (p = 0.047), and 12.9 ± 14.66 kg (p = 0.121), respectively. The level of serum ghrelin decreased by 40.83% (p = 0.009), 31.94% (p = 0.107), and 24.82% (p = 0.151) at 3, 6, and 9 months after LGAE, respectively. There was minimal reduction of leptin levels at 3 and 6 months following LGAE (decreased by 0.26%, p = 0.929, and 4.33%, p = 0.427, respectively), but it declined obviously 9 months after LGAE (decreased by 11.22%, p = 0.295). Both waist circumference and waist-to-height ratio decreased after LGAE. MRI showed the area of subcutaneous adipose tissue decreased from the baseline of 400.90 ± 79.25 to 320.36 ± 68.06 cm2 (decreased by 20.09%, p = 0.006) at 3 months, to 328.31 ± 52.67 cm2 (decreased by 18.11%, p = 0.020) at 6 months, and to 286.40 ± 55.72 cm2 (decreased by 28.52%, p = 0.101) at 9 months after LGAE, respectively. But the decrease of abdominal fat loss at 9 months after LGAE was largely due to the reduction in visceral adipose tissue. Our study with 9-month data in 5 patients indicates that bariatric embolization of the LGA is a safe and may be a promising strategy to suppress the production of ghrelin and results in weight loss and abdominal fat reduction. ClinicalTrials.gov (NCT02786108).

The wireless access networks have witnessed an explosive growth in home and enterprise applications. However, to meet the tough performance requirements, such as seamless handover, higher throughput, and agile programing, there still exists many challenges in WiFi networks. In this paper, we propose a novel MP-SDWN (multipath-supported Software Defined Wireless Network), to provide mobility handover, throughput enhancement, and flow-level transmission control as well as programmable system control interfaces. Furthermore, the effectiveness and efficiency of MP-SDWN is evaluated on an experimental prototype.

The cellular networks in China are growing rapidly, thus various radio complex technologies, from 2G to 4G are deployed to support billions of mobile users. In this paper, we take a first attempt to analyze cellular network latency in China. A mobile app NetSense (The application is available at: https://github.com/lovesick/NetSense/) was scattered up on several hundred mobile terminals to measure the latency at large. Based on the measured results of 4 months, we find out that: (i) China’s cellular network adopts hierarchical structure, with more gateways deployed in capital or major cities for each province; (ii) the latency varies largely across geographical locations, ISPs and is also dependent on the deployed cellular technologies; (iii) Considering end-to-end latency, the last mile delay contributes over 70 percentage for the whole transmission latency.

In this letter, we propose an access point (AP) sleeping and user offloading optimization scheme to improve energy efficiency in densely deployed WLANs. Through real trace analysis, we investigate AP energy efficiency to obtain the sleep-awake threshold, which is used to select sleep or awake APs according to real-time status information monitored on controller. Moreover, we formulate the user offloading problem as a reverse auction process to optimize energy efficiency of APs involved in offloading. Simulation results demonstrate that, comparing to traditional methods, our scheme can achieve up to 20% energy saving while maintaining effective system coverage and throughput.