A GIS-Based Evaluation of Environmental Sensitivity for an Urban Expressway in Shenzhen, China

Urban eco-environmental degradation is becoming inevitable due to the extensive urbanization, popula- tion growth, and socioeconomic development in China. One of the traffic arteries in Shenzhen is an urban expressway that is under construction and that runs across environmentally sensitive areas （ESAs）. The environmental pollution from urban expressways is critical, due to the characteristics of expressways such as high runoff coefficients, considerable contaminant accumulation, and complex pollutant ingredi- ents. ESAs are vulnerable to anthropogenic disturbances and hence should be given special attention. In order to evaluate the environmental sensitivity along this urban expressway and minimize the influences of the ongoing road construction and future operation on the surrounding ecosystem, the environmental sensitivity of the relevant area was evaluated based on the application of a geographic information sys- tem （GIS）. A final ESA map was classified into four environmental sensitivity levels; this classification indicates that a large proportion of the expressway passes through areas of high sensitivity, representing 11.93 km or 52.3% of the total expressway, and more than 90% of the total expressway passes through ESAs. This study provides beneficial information for optimal layout schemes of initial rainfall runofftreatment facilities developed from low-impact development （LID） techniques in order to minimize the impact of polluted road runoff on the surrounding ecological environment.

Introduction to the special issue on polarization of light in biomedical applications

Although birefringence was discovered just three years after white light was separated into different colors,polarimetry has lagged behind spectroscopy in characterizing diverse materials,likely due to our naked eyes'limited sensitivity to polarizations.Recent advancements in light sources,polarization optics,detectors,displays,data processing,and feature extraction techniques are rapidly propelling polarimetry as a convenient and potent tool for probing the distinct properties of complex and turbid materials.It is well known now that polarization properties of a material encode rich information on its distinct features,including not only the bulk optical properties related with dispersions and absorptions,but also distribution and microstructural properties of the scattering particles in turbid media such as the size,shape,orientation and alignment,surface morphology and internal structure,etc.All these features can be used for differentiating different materials,sensing ambient environment around scatterers,or monitoring dynamic processes in complex systems.

A short review on natural gas hydrate, kinetic hydrate inhibitors and inhibitor synergists

Gas hydrate-caused pipeline plugging is an industrial nuisance for petroleum flow assurance that calls for technological innovations.Traditional thermodynamic inhibitors such as glycols and inorganic salts suffer from high dosing,environmental unfriendliness,corrosiveness,and economical burden.The development and use of kinetic hydrate inhibitors(KHIs),mostly polymeric compounds,with their inhibiting effects on hydrate nucleation and growth are considered an effective and economically viable chemical treatment for hydrate prevention.However,the actual performance of a KHI candidate is dependent on various factors including its chemical structure,molecular weight,spatial configuration,effective concentration,pressure and temperature,evaluation methods,use of other additives,etc.This review provides a short but systematic overview of the fundamentals of natural gas hydrates,the prevailing categories of polymeric kinetic hydrate inhibitors with proposed inhibition mechanisms,and the various synergists studied for boosting the KHI performance.Further research endeavors are in need to unveil the KHI working modes under different conditions.The conjunctive use of KHIs and synergists may facilitate the commercial application of effective KHIs to tackle the hydrate plugging problem in the oil and gas flow assurance practices.

A review of lithium-ion battery safety concerns:The issues,strategies,and testing standards

Efficient and reliable energy storage systems are crucial for our modern society.Lithium-ion batteries(LIBs)with excellent performance are widely used in portable electronics and electric vehicles(EVs),but frequent fires and explosions limit their further and more widespread applications.This review summarizes aspects of LIB safety and discusses the related issues,strategies,and testing standards.Specifically,it begins with a brief introduction to LIB working principles and cell structures,and then provides an overview of the notorious thermal runaway,with an emphasis on the effects of mechanical,electrical,and thermal abuse.The following sections examine strategies for improving cell safety,including approaches through cell chemistry,cooling,and balancing,afterwards describing current safety standards and corresponding tests.The review concludes with insights into potential future developments and the prospects for safer LIBs.

A review on the application of modified continuum models in modeling and simulation of nanostructures

Analysis of the mechanical behavior of nanos- tructures has been very challenging. Surface energy and non- local elasticity of materials have been incorporated into the traditional continuum analysis to create modified continuum mechanics models. This paper reviews recent advancements in the applications of such modified continuum models in nanostructures such as nanotubes, nanowires, nanobeams, graphenes, and nanoplates. A variety of models for these nanostructures under static and dynamic loadings are men- tioned and reviewed. Applications of surface energy and nonlocal elasticity in analysis of piezoelectric nanomateri- als are also mentioned. This paper provides a comprehensive introduction of the development of this area and inspires fur- ther applications of modified continuum models in modeling nanomaterials and nanostructures.

Novel Insights into Energy Storage Mechanism of Aqueous Rechargeable Zn/MnO2 Batteries with Participation of Mn2+

Aqueous rechargeable Zn/MnO2 zinc-ion batteries(ZIBs)are reviving recently due to their low cost,non-toxicity,and natural abundance.However,their energy storage mechanism remains controversial due to their complicated electrochemical reactions.Meanwhile,to achieve satisfactory cyclic stability and rate performance of the Zn/MnO2 ZIBs,Mn2+ is introduced in the electrolyte(e.g.,ZnSO4 solution),which leads to more complicated reactions inside the ZIBs systems.Herein,based on comprehensive analysis methods including electrochemical analysis and Pourbaix diagram,we provide novel insights into the energy storage mechanism of Zn/MnO2 batteries in the presence of Mn2+.A complex series of electrochemical reactions with the coparticipation of Zn2+,H+,Mn2+,SO42-,and OH-were revealed.During the first discharge process,co-insertion of Zn2+ and H+ promotes the transformation of MnO2 into ZnxMnO4,MnOOH,and Mn2O3,accompanying with increased electrolyte pH and the formation of ZnSO4·3 Zn(OH)2-5 H2O.During the subsequent charge process,ZnxMnO4,MnOOH,and Mn2O3 revert to a-MnO2 with the extraction of Zn2+ and H+,while ZnSO4·3Zn(OH)2·5H2O reacts with Mn2+ to form ZnMn3O7·3 H2O.In the following charge/discharge processes,besides aforementioned electrochemical reactions,Zn2+ reversibly insert into/extract from α-MnO2,ZnxMnO4,and ZnMn3O7·3H2O hosts;ZnSO4·3Zn(OH)2·5 H2O,Zn2Mn3O8,and ZnMn2O4 convert mutually with the participation of Mn2+.This work is believed to provide theoretical guidance for further research on high-performance ZIBs.

Review and prospect of NiCo_(2)O_(4)-based composite materials for supercapacitor electrodes

Supercapacitors known as typical electrochemical capacitors have been considered as one of the most promising candidates of energy storage systems owing to their advantages such as high-power density,long life span and lower production cost.The electrode materials play a crucial role on properties of supercapacitors.Hence,many researches have been focused on the development of novel electrode materials for high-performance supercapacitors.NiCo_2O_4as supercapacitor electrode material has drawn more and more attentions in recent years due to its outstanding advantages,such as high theoretical capacity,low cost,natural abundance and easy of synthesis.However,the NiCo_2O_4always suffer from severe capacity deterioration because of the low electrical conductivity and small surface area.Hence,it is necessary to systematically and comprehensively summarize the progress in understanding and modifying NiCo_2O_4-based materials from various aspects.In this review,the structure and synthesis method of NiCo_2O_4-based materials are discussed in detail.And then,the major goal of this review is to highlight new progress in using proposed strategies to improve the cycling stability and rate capacity of NiCo_2O_4-based materials,including synthesis,control of special morphologies and design of composite materials.Finally,an insight into the future research and development of Ni Co_2O_4-based materials for supercapacitors is prospected.

Growth and Repair Potential of Three Species of Bacteria in Reclaimed Wastewater after UV Disinfection

Objective The growth and repair potential of three typical microorganisms in reclaimed water after UV disinfection was investigated to assess the effects of photo-reactivation and dark repair of microorganisms,and the microbial safety of reclaimed water following this procedure.Methods The growth and repair potential of Escherichia coli,a fecal coliform strain and Bacillus subtilis in the effluent of a biological wastewater treatment plant disinfected by a low-pressure UV lamp were investigated.Results Any increase in bacterial numbers in the effluent after UV disinfection was due to damage repair.Exposure to photo-reactivating light for 8-10 h after UV irradiation with a dose of 5 mJ/cm 2,the highest percentage of photo-reactivation observed for E.coli and the fecal coliform strain was 29% and 15% respectively.B.subtilis showed little photo-reactivation under these conditions.The percentage of photo-reactivation was related to the UV dose and the photo-reactivating time,and a function was developed to forecast the final concentrations of E.coli and the fecal coliform strain after UV disinfection with possible photo-reactivation.Conclusion Different species of bacteria displayed different responses to UV light and different repair potentials.The repair of indigenous bacteria in wastewater needs to be investigated in future work.

Precise carbon structure control by salt template for high performance sodium-ion storage

Carbon materials are considered to be one of the most promising anode materials for sodium-ion batteries(SIBs),but the well-ordered graphitic structure limits the intercalation of sodium ions.Besides,the sluggish intercalation kinetics of sodium ions impedes the rate performance.Thus,the precise structure control of carbon materials is important to improve the battery performance.Herein,a 3D porous hard-soft composite carbon(3DHSC)was prepared using the NaCl as the template and phenolic resin and pitch as carbon precursors.The NaCl template restrains the growth of the graphite crystallite during the carbonization process,resulting in small graphitic domains with expanded interlayer spacing which is favorable for the sodium storage.Moreover,the Na Cl templates help to create abundant mesopores and macropores for fast sodium ion diffusion.The porous structure and the graphite crystalline structure can be precisely controlled by simply adjusting the mass ratio of Na Cl,and thus,the suitable structure can be prepared to reach high capacity and rate performance while keeping a relatively high Coulombic efficiency.Typically,a high reversible capacity(215 mA h g^(-1)at 0.05 A g^(-1)),an excellent rate capability(97 mA h g^(-1)at 5 A g^(-1)),and a high initial Coulombic efficiency(60%)are achieved.

An ultrathin and continuous Li_4Ti_5O_(12) coated carbon nanofiber interlayer for high rate lithium sulfur battery

Severe capacity fading and poor high rate performance of lithium sulfur(Li–S) battery caused by "shuttle effect" and low conductivity of sulfur hampers its further developments and applications. Li_4Ti_5O_(12) (LTO)possesses high lithium ion conductivity, and it is also can be used as an active adsorbent for polysulfide. Herein, fine LTO particle coated carbon nanofibers(CNF) were prepared and a conductive network both for electron and lithium ion was built, which can greatly promote the electrochemical conversion of polysulfide and improve the rate performance of Li–S batteries. Meanwhile, a quantity of adsorption sites is constructed by defects of the surface of LTO-CNF membrane to effectively immobilize polysulfide. The multifunctional LTO-CNF interlayer could impede the shuttle effect and enhance comprehensive electrochemical performance of Li–S batteries, especially high rate performance. With such LTO-CNF interlayer,the Li–S battery presents a specific capacity of 641.9 mAh/g at 5 C rate. After 400 cycles at 1 C, a capacity of 618.0 mAh/g is retained. This work provides a feasible strategy to achieve high performance of Li–S battery for practical utilization.

Multifunctional binder designs for lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries are promising next-generation high energy density batteries but their practical application is hindered by several key problems,such as the intermediate polysulfide shuttling and the electrode degradation caused by the sulfur volume changes.Binder acts as one of the most essential components to build the electrodes of Li-S batteries,playing vital roles in improving the performance and maintaining the integrity of the cathode structure during cycling,especially those with high sulfur loadings.To date,tremendous efforts have been devoted to improving the properties of binders,in terms of the viscosity,elasticity,stability,toughness and conductivity,by optimizing the composition and structure of polymer binders.Moreover,the binder modification endows them strong polysulfide trapping ability to suppress the shuttling and decreases the swelling to maintain the porous structure of cathode.In this review,we summarize the recent progress on the binders for Li-S batteries and discuss the various routes,including the binder combination use,functionalization,in-situ polymerization and ion cross-linking,etc.,to enhance their performance in stabilizing the cathode,building the high sulfur loading electrode and improving the cyclic stability.At last,the design principles and the problems in further applications are also highlighted.

Progress and perspective of the cathode/electrolyte interface construction in all-solid-state lithium batteries

Security risks of flammability and explosion represent major problems with the use of conventional lithium rechargeable batteries using a liquid electrolyte.The application of solid-state electrolytes could effectively help to avoid these safety concerns.However,integrating the solid-state electrolytes into the all-solid-state lithium batteries is still a huge challenge mainly due to the high interfacial resistance present in the entire battery,especially at the interface between the cathode and the solid-state electrolyte pellet and the interfaces inside the cathode.Herein,recent progress made from investigations of cathode/solid-state electrolyte interfacial behaviors including the contact problem,the interlayer diffusion issue,the space-charge layer effect,and electrochemical compatibility is presented according to the classification of oxide-,sulfide-,and polymer-based solid-state electrolytes.We also propose strategies for the construction of ideal next-generation cathode/solid-state electrolyte interfaces with high room-temperature ionic conductivity,stable interfacial contact during long cycling,free formation of the space-charge region,and good compatibility with high-voltage cathodes.

Study on Internal Waves Generated by Tidal Flow over Critical Topography

Resonance due to critical slope makes the internal wave generation more effectively than that due to supercritical or subcritical slopes(Zhang et al., 2008). Submarine ridges make a greater contribution to ocean mixing than continental margins in global oceans(Müller, 1977; Bell, 1975; Baines, 1982; Morozov, 1995). In this paper, internal wave generation driven by tidal flow over critical topography is examined in laboratory using Particle Image Velocimetry(PIV) and synthetic schlieren methods in synchrony. Non-tidal baroclinic velocities and vertical isopycnal displacements are observed in three representative regions, i.e., critical, outward-propagating, and reflection regions. Temporal and spatial distributions of internal wave rays are analyzed using the time variations of baroclinic velocities and vertical isopycnal displacement, and the results are consistent with those by the linear internal wave theory. Besides, the width of wave beam changes with the outward propagation of internal waves. Finally, through monitoring the uniformly-spaced 14 vertical profiles in the x-z plane, the internal wave fields of density and velocity fields are constructed. Thus, available potential energy, kinetic energy and energy fluxes are determined quantitatively. The distributions of baroclinic energy and energy fluxes are confined along the internal wave rays. The total depth averaged energy and energy flux of vertical profiles away from a ridge are both larger than those near the ridge.

Corrosion behaviors of arc spraying single and double layer coatings in simulated Dagang soil solution

Three kinds of single layer coatings of Zn,Zn15Al,316L stainless steel and two kinds of double layer coatings with inner layer of Zn or Zn15Al and outer layer of 316L stainless steel by arc spraying were developed to protect the metal ends of prestressed high-strength concrete(PHC)pipe piles against soil corrosion.The corrosion behaviors of the coated Q235 steel samples in the simulated Dagang soil solution were investigated by potentiodynamic polarization,electrochemical impedance spectroscopy(EIS) and natural immersion tests.The results show that the corrosion of the matrix Q235 steel is effectively inhibited by Zn,Zn15Al, Zn+316L and Zn15Al+316L coatings.The corrosion rate value of Zn15Al coated samples is negative.The corrosion products on Zn and Zn15Al coated samples are compact and firm.The corrosion resistance indexes of both Zn and Zn15Al coated samples are improved significantly with corrosion time,and the latter are more outstanding than the former.But the corrosion resistance of 316L coated samples is decreased quickly with the increase in immersion time.When the coatings are sealed with epoxy resin,the corrosion resistance of the coatings will be enhanced significantly.

Seasonal and spatial variation in species diversity, abundance, and element accumulation capacities of macroalgae in mangrove forests of Zhanjiang, China

The objective of this study was to investigate whether there was distinctive seasonal and zonal variation in the species diversity, biomass, and element accumulation capacities of macroalgae in two major intertidal mangrove stand types （Avicennia marina assemblage andSonneratia apetala assemblage） in the Zhanjiang region of southern China. Over a year, 31 species in 15 genera were identified in both mangrove assem-blages, of which the dominant species wereCladophoropsis zollingeriand Enteromorpha clathrat.Macroal-gal species were significantly most abundant in spring （p〈0.05）, followed by summer, winter, and autumn. Variation in the zonal distribution of macroalgal species was conspicuous in both intertidal mangrove as-semblages, with the greatest abundance in the middle zone, and the least in the front zone. Patterns in the seasonal and zonal variation in macroalgal biomass in theS. apetalaassemblage were similar to those of macroalgal species diversity in both mangrove assemblages. The seasonal patterns in tissue concentrations of 15 analyzed elements were not uniform among the macroalgaeC. zollingeri,E. clathrata, andGracilaria salicornia in theA. marina assemblage. All three species exhibited variation in their responses to ambient concentrations of different elements, implying their differential ability to absorb and selectively accumulate certain elements.

Vibration analysis of piezoelectric sandwich nanobeam with flexoelectricity based on nonlocal strain gradient theory

A nonlocal strain gradient theory(NSGT) accounts for not only the nongradient nonlocal elastic stress but also the nonlocality of higher-order strain gradients,which makes it benefit from both hardening and softening effects in small-scale structures.In this study, based on the NSGT, an analytical model for the vibration behavior of a piezoelectric sandwich nanobeam is developed with consideration of flexoelectricity. The sandwich nanobeam consists of two piezoelectric sheets and a non-piezoelectric core. The governing equation of vibration of the sandwich beam is obtained by the Hamiltonian principle. The natural vibration frequency of the nanobeam is calculated for the simply supported(SS) boundary, the clamped-clamped(CC) boundary, the clamped-free(CF)boundary, and the clamped-simply supported(CS) boundary. The effects of geometric dimensions, length scale parameters, nonlocal parameters, piezoelectric constants, as well as the flexoelectric constants are discussed. The results demonstrate that both the flexoelectric and piezoelectric constants enhance the vibration frequency of the nanobeam.The nonlocal stress decreases the natural vibration frequency, while the strain gradient increases the natural vibration frequency. The natural vibration frequency based on the NSGT can be increased or decreased, depending on the value of the nonlocal parameter to length scale parameter ratio.

Electrochemical Corrosion Behavior of Arc Sprayed Zn and Zn15Al Coatings in Simulated Salina Soil and Neutral Meadow Soil Solutions

Arc sprayed Zn and Zn15Al coatings were chosen to protect the metal ends of prestressed high-strength concrete （PHC） pipe piles against corrosion of salina soil in northern china and neutral meadow soil in northeast China. The corrosion behavior of the coated Q235 steel samples in two simulated soil solutions were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy （EIS） methods. The experimental results show that the corrosion of the matrix Q235 steel in both simulated solutions is remarkably inhibited by Zn and Zn15Al coatings. The corrosion products on Zn and Zn15Al are thick, compact, firm and protective. The corrosion current density icorr of both Zn and Zn15Al-coated samples is decreased evidently with corrosion time, and the charge transfer resistance Rct is increased greatly. The corrosion resistance indexes of Zn and Zn15Al in simulated neutral meadow soil solution are more outstanding than those in salina soil. The corrosion resistance of Zn15Al in salina soil is slightly superior to that of Zn. When the sprayed coatings are sealed with epoxy resin, the corrosion resistance of the coatings is further enhanced markedly.

Neural network approach to blindestimation of PN spreading sequence in lower SNR DS/SS signals

An approach based on discrete Karhunen-Loeve transformation of the DS/SS signals is proposed to estimate PN sequence in lower S/N ratio DS/SS signals. Characteristics of self-organization and principle components extraction of unsupervised neural networks are exploited adequately. Theoretical analysis and experimental results are provided to show that this approach can work well on the lower S/N ratio input signals.

A Silicon Monoxide Lithium-Ion Battery Anode with Ultrahigh Areal Capacity

Silicon monoxide(SiO)is an attractive anode material for next-generation lithium-ion batteries for its ultra-high theoretical capacity of 2680 mAh g−1.The studies to date have been limited to electrodes with a rela-tively low mass loading(<3.5 mg cm^(−2)),which has seriously restricted the areal capacity and its potential in practical devices.Maximizing areal capacity with such high-capacity materials is critical for capitalizing their potential in practi-cal technologies.Herein,we report a monolithic three-dimensional(3D)large-sheet holey gra-phene framework/SiO(LHGF/SiO)composite for high-mass-loading electrode.By specifically using large-sheet holey graphene building blocks,we construct LHGF with super-elasticity and exceptional mechanical robustness,which is essential for accommodating the large volume change of SiO and ensuring the structure integrity even at ultrahigh mass loading.Additionally,the 3D porous graphene network structure in LHGF ensures excellent electron and ion transport.By systematically tailoring microstructure design,we show the LHGF/SiO anode with a mass loading of 44 mg cm^(−2)delivers a high areal capacity of 35.4 mAh cm^(−2)at a current of 8.8 mA cm^(−2)and retains a capacity of 10.6 mAh cm^(−2)at 17.6 mA cm^(−2),greatly exceeding those of the state-of-the-art commercial or research devices.Furthermore,we show an LHGF/SiO anode with an ultra-high mass loading of 94 mg cm^(−2)delivers an unprecedented areal capacity up to 140.8 mAh cm^(−2).The achievement of such high areal capacities marks a critical step toward realizing the full potential of high-capacity alloy-type electrode materials in practical lithium-ion batteries.

Nanostructured Anode Materials for Non-aqueous Lithium Ion Hybrid Capacitors

The rapid advancement in electronic devices,electric vehicles,and grid storage stations have lead to a high demand for energy storage devices with enhanced power and energy densities as well as extended lifespans.Lithium ion hybrid capacitors are constructed with battery-type anodes and capacitor-type cathodes,which enables the direct integration of the high energy from lithium ion batteries and high power and long lifetime from supercapacitors,making lithium ion hybrid capacitor one of the most promising energy storage devices.In the past two decades,tremendous efforts have been put into the search for suitable battery-type anode materials with improved Faradaic reaction kinetics so that it can match with the fast non-Faradaic charging rate of the capacitive cathodes.This review aims to provide an up-to-date and comprehensive summary of the battery-type anode materials for high-performance lithium ion hybrid capacitors.To date,a large variety of battery-type anode materials have been explored with smart material design strategies,such as carbonaceous materials,metal oxides,alloys,sulfides,nitirdes,and Mxenes,etc.,which will be discussed in detail.A perspective to the challenges and future developing trends of lithium ion hybrid capacitors is proposed to close.