查看更多>>摘要：Highway maintenance mileage reached 5.25 million kilometers in China by 2021.Ultra-thin overlay is one of the most commonly used maintenance technologies,which can significantly enhance the eco-nomic and environmental benefits of pavements.To promote the low-carbon development of ultra-thin overlays,this paper mainly studied the mechanism and influencing factors of several ultra-thin over-lay functions.Firstly,the skid resistance,noise reduction,rutting resistance,and crack resistance of ultra-thin overlays were evaluated.The results indicated that the high-quality aggregates improved the skid and rutting resistance of ultra-thin overlay by 5％-20％.The optimized gradations and modified binders reduced noise of ultra-thin overlay by 0.4-6.0 dB.The high viscosity modified binders improved the rut-ting resistance of ultra-thin overlay by about 10％-130％.Basalt fiber improved the cracking resistance of ultra-thin overlay by more than 20％.Due to the thinner thickness and better road performance,the performance-based engineering cost of ultra-thin overlay was reduced by about 30％-40％compared with conventional overlays.Secondly,several environmentally friendly functions of ultra-thin overlay were investigated,including snow melting and deicing,exhaust gas purification and pavement cooling.The lower thickness of ultra-thin overlay was conducive to the diffusion of chloride-based materials to the pavement surface.Therefore,the snow melting effect of self-ice-melting was better.In addition,the ultra-thin overlay mixture containing photocatalytic materials could decompose 20％-50％of the exhaust gas.The colored ultra-thin overlay was able to reduce the temperature of the pavement by up to 8.1 ℃.The temperature difference between the upper and lower surfaces of the ultra-thin overlay containing thermal resistance materials could reach up to 12.8 ℃.In addition,numerous typical global engineering applications of functional ultra-thin overlay were summarized.This review can help better understand the functionality of ultra-thin overlays and promote the realization of future multi-functional and low-carbon road maintenance.
查看更多>>摘要：Over the past few decades,one of the most significant advances in dam construction has been the inven-tion of the rock-filled concrete(RFC)dam,which is constructed by pouring high-performance self-compacting concrete(HSCC)to fill the voids in preplaced large rocks.The innovative use of large rocks in dam construction provides engineers with a material that requires less cement consumption and hydration heat while enhancing construction efficiency and environmental friendliness.However,two fundamental scientific issues related to RFC need to be addressed:namely,the pouring compactness and the effect of large rocks on the mechanical and physical properties of RFC.This article provides a timely review of fundamental research and innovations in the design,construction,and quality control of RFC dams.Prospects for next-generation concrete dams are discussed from the perspectives of envi-ronmental friendliness,intrinsic safety,and labor savings.
查看更多>>摘要：Understanding the vertical distribution of ozone is crucial when assessing both its horizontal and vertical transport,as well as when analyzing the physical and chemical properties of the atmosphere.One of the most effective ways to obtain high spatial resolution ozone profiles is through satellite observations.The Environmental Trace Gases Monitoring Instrument(EMI)deployed on the Gaofen-5 satellite is the first Chinese ultraviolet-visible hyperspectral spectrometer.However,retrieving ozone profiles using backscattered radiance values measured by the EMI is challenging due to unavailable measurement errors and a low signal-to-noise ratio.The algorithm developed for the Tropospheric Monitoring Instrument did not allow us to retrieve 87％of the EMI pixels.Therefore,we developed an algorithm specific to the characteristics of the EMI.The fitting residuals are smaller than 0.3％in most regions.The retrieved ozone profiles were in good agreement with ozonesonde data,with maximum mean biases of 20％at five latitude bands.By applying EMI averaging kernels to the ozonesonde profiles,the integrated stratospheric column ozone and tropospheric column ozone also showed excellent agreement with ozo-nesonde data.The lower layers(0-7.5 km)of the EMI ozone profiles reflected the seasonal variation in surface ozone derived from the China National Environmental Monitoring Center(CNEMC).However,the upper layers(9.7-16.7 km)of the ozone profiles show different trends,with the ozone peak occurring at an altitude of 9.7-16.7 km in March,2019.A stratospheric intrusion event in central China from August 11 to 15,2019,is captured using the EMI ozone profiles,potential vorticity data,and relative humidity data.The increase in the CNEMC ozone concentration showed that downward transport enhanced surface ozone pollution.
查看更多>>摘要：Mechanical pretreatment is an indispensable process in biological treatment plants that remove plastics and other impurities from household biogenic waste(HBW).However,the imperfect separation of plas-tics in these pretreatment methods has raised concerns that they pose a secondary formation risk for microplastics(MPs).To validate this presumption,herein,quantities and properties of plastic debris and MPs larger than 50 pm were examined in the full chain of three different pretreatment methods in six plants.These facilities received HBW with or without prior depackaging at the source.The key points in the secondary formation of MPs were identified.Moreover,flux estimates of MPs were released,and an analysis of MPs sources was provided to develop an overview of their fate in HBW pretreatment.Pretreated output can contain a maximum of(1673±279)to(3198±263)MP particles per kilogram of wet weight(particles·kg-1 ww)for those undepackaged at source,and secondary MPs formation is pri-marily attributed to biomass crushers,biohydrolysis reactors,and rough shredders.Comparatively,HBW depackaged at the source can greatly reduce MPs by 8％-72％,regardless of pretreatment processes.Before pretreatment,4.6-205.6 million MP particles were present in 100 tonnes of HBW.MPs are pro-duced at a rate of 741.11-33124.22 billion MP particles annually in anaerobic digester feedstock(ADF).This study demonstrated that HBW pretreatment is a competitive source of MPs and emphasized the importance of implementing municipal solid waste segregation at the source.Furthermore,depack-aging biogenic waste at the source is recommended to substantially alleviate the negative effect of pre-treatment on MPs formation.
Jun Hwan MoonTaesoon KimYoungmin LeeSeunghyun Kim...
127-137页
查看更多>>摘要：Achieving historically anticipated improvement in the performance of integrated circuits is challenging,due to the increasing cost and complexity of the required technologies with each new generation.To overcome this limitation,the exploration and development of novel interconnect materials and processes are highly desirable in the microelectronics field.Molybdenum(Mo)is attracting attention as an advanced interconnect material due to its small resistivity size effect and high cohesive energy;however,effective processing methods for such materials have not been widely investigated.Here,we investigate the electrochemical behavior of ions in the confined nanopores that affect the electrical properties and microstructures of nanoscale Mo and Mo-Co alloys prepared via template-assisted electrodeposition.Additives in an electrolyte allow the deposition of extremely pure metal materials,due to their interac-tion with metal ions and nanopores.In this study,boric acid and tetrabutylammonium bisulfate(TBA)were added to an acetate bath to inhibit the hydrogen evolution reaction.TBA accelerated the reduction of Mo at the surface by inducing surface conduction on the nanopores.Metallic Mo nanowires with a 130 nm diameter synthesized through high-aspect-ratio nanopore engineering exhibited a resistivity of(63.0±17.9)μΩ·cm.We also evaluated the resistivities of Mo-Co alloy nanowires at various compo-sitions toward replacing irreducible conventional barrier/liner layers.An intermetallic compound formed at a Mo composition of 28.6 at％,the resistivity of the Mo-Co nanowire was(58.0±10.6)μΩ.cm,indicat-ing its superior electrical and adhesive properties in comparison with those of conventional barriers such as TaN and TiN.Furthermore,density functional theory and non-equilibrium Green's function calcula-tions confirmed that the vertical resistance of the via structure constructed from Mo-based materials was 21％lower than that of a conventional Cu/Ta/TaN structure.
查看更多>>摘要：Fluid flow at nanoscale is closely related to many areas in nature and technology(e.g.,unconventional hydrocarbon recovery,carbon dioxide geo-storage,underground hydrocarbon storage,fuel cells,ocean desalination,and biomedicine).At nanoscale,interfacial forces dominate over bulk forces,and nonlinear effects are important,which significantly deviate from conventional theory.During the past decades,a series of experiments,theories,and simulations have been performed to investigate fluid flow at nanos-cale,which has advanced our fundamental knowledge of this topic.However,a critical review is still lack-ing,which has seriously limited the basic understanding of this area.Therefore herein,we systematically review experimental,theoretical,and simulation works on single-and multi-phases fluid flow at nanos-cale.We also clearly point out the current research gaps and future outlook.These insights will promote the significant development of nonlinear flow physics at nanoscale and will provide crucial guidance on the relevant areas.
查看更多>>摘要：In recent years,a great deal of attention has been focused on the environmental impact of plastics,includ-ing the carbon emissions related to plastics,which has promoted the application of biodegradable plas-tics.Countries worldwide have shown high interest in replacing traditional plastics with biodegradable plastics.However,no systematic comparison has been conducted on the carbon emissions of biodegrad-able versus traditional plastic products.This study evaluates the carbon emissions of traditional and biodegradable plastic products(BPPs)over four stages and briefly discusses environmental and economic perspectives.Four scenarios-namely,the traditional method,chemical recycling,industrial composting,and anaerobic digestion-are considered for the disposal of waste BPPs(WBPPs).The analysis takes China as a case study.The results show that the carbon emissions of 1000 traditional plastic products(plastic bags,lunch boxes,cups,etc.)were 52.09-150.36 carbon emissions equivalent of per kilogram(kg CO2eq),with the stage of plastic production contributing 50.71％-50.77％.In comparison,1000 similar BPPs topped out at 21.06-56.86 kg CO2eq,approximately 13.53％-62.19％lower than traditional plastic prod-ucts.The difference was mainly at the stages of plastic production and waste disposal,and the BPPs showed significant carbon reduction potential at the raw material acquisition stage.Waste disposal plays an important role in environmental impact,and composting and anaerobic digestion are considered to be preferable disposal methods for WBPPs.However,the high cost of biodegradable plastics is a challenge for their widespread use.This study has important reference significance for the sustainable development of the biodegradable plastics industry.
查看更多>>摘要：The emergence and spread of the mobile colistin-resistance gene,mcr-1,and its variants pose a challenge to the use of colistin,a last-resort antibiotic used to treat severe infections caused by extensively drug-resistant(XDR)Gram-negative pathogens.Antibiotic adjuvants are a promising strategy to enhance the efficacy of colistin against colistin-resistant pathogens;however,few studies have considered the effects of adjuvants on limiting resistance-gene transmission.We found that chelerythrine(4 mg·L-1)derived from Macleaya cordata extract,which is used as an animal feed additive,reduced the minimal inhibitory concentration(MIC)of colistin against an mcr-1 positive Escherichia coli(E.coli)strain by 16-fold(from 2.000 to 0.125 mg·L-1),eliminated approximately 104 colony-forming units(CFUs)of an mcr-1-carrying strain in a murine intestinal infection model,and inhibited the conjugation of an mcr-1-bearing plasmid in vitro(by＞100-fold)and in a mouse model(by up to 5-fold).A detailed analysis revealed that chelery-thrine binds to phospholipids on bacterial membranes and increases cytoplasmic membrane fluidity,thereby impairing respiration,disrupting proton motive force(PMF),generating reactive oxygen species(ROS),and decreasing intracellular adenosine triphosphate(ATP)levels,which subsequently downregu-lates mcr-1 and conjugation-associated genes.These dual effects of chelerythrine can expand the use of antibiotic adjuvants and may provide a new strategy for circumventing mobile colistin resistance.
查看更多>>摘要：Chronic hepatitis B virus(HBV)infection,which threatens global public health,is a major contributor to liver-related morbidity and mortality.Examinations for liver diseases related to chronic HBV infection-including laboratory tests,ultrasounds,computed tomography(CT),and liver biopsies-may take up medical resources,particularly since they overlap in most instances.Thus,there is an urgent need to establish an economical and effective diagnosis method in order to streamline the medical process for HBV-related diseases.Using complex network models constructed based on clinical blood tests,we pro-vide such a method by defining the novel measure of functional resilience to assess patients'liver condi-tions.By combining network models and dynamics,we discovered the pivotal items and their corresponding thresholds,which can guide further research on preventing disease deterioration in crit-ical states of these diseases.The macro-averaged precision of our method,functional resilience,is 84.74％,whereas the macro-averaged precision of physicians'experience without assistance from imag-ing or biopsy is 55.63％.From an economic perspective,our approach could save the equivalent of at least 30 USD per visit for most Chinese patients and at least 400 USD per visit for most US patients,compared with general diagnostic methods.Globally,this will add to savings of at least 10.5 billion USD annually.Our method can comprehensively evaluate the condition of patients'livers and help avert the waste of medical resources during the diagnosis of liver disease by reducing excessive imaging exams.
查看更多>>摘要：Industrial robots are becoming increasingly vulnerable to cyber incidents and attacks,particularly with the dawn of the Industrial Internet-of-Things(IIoT).To gain a comprehensive understanding of these cyber risks,vulnerabilities of industrial robots were analyzed empirically,using more than three million communication packets collected with testbeds of two ABB IRB120 robots and five other robots from var-ious original equipment manufacturers(OEMs).This analysis,guided by the confidentiality-integrity-availability(CIA)triad,uncovers robot vulnerabilities in three dimensions:confidentiality,integrity,and availability.These vulnerabilities were used to design Covering Robot Manipulation via Data Deception(CORMAND2),an automated cyber-physical attack against industrial robots.CORMAND2 manipulates robot operation while deceiving the Supervisory Control and Data Acquisition(SCADA)system that the robot is operating normally by modifying the robot's movement data and data deception.CORMAND2 and its capability of degrading the manufacturing was validated experimentally using the aforementioned seven robots from six different OEMs.CORMAND2 unveils the limitations of existing anomaly detection systems,more specifically the assumption of the authenticity of SCADA-received movement data,to which we propose mitigations for.
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