In vertical channel transistors(VCTs),source/drain ion implantation(I/I)represents a significant technical challenge due to inherent three-dimensional structural constraints,which induce complications such as difficul...In vertical channel transistors(VCTs),source/drain ion implantation(I/I)represents a significant technical challenge due to inherent three-dimensional structural constraints,which induce complications such as difficulties in dummy gate forma-tion and shadowing effects of I/I.This article systematically investigates the impact of different implantation conditions on the performance of VCTs with and without dummy gates through TCAD simulation.It reveals the significant role of the lightly doped regions(LDRs)naturally formed due to ion implantation in source/drain of VCTs.Furthermore,it was found that VCT with-out dummy gates can achieve an approximately 27%increase in on-state current(Ion)under the same implantation conditions,and can greatly simplify the process flow and reduce costs.Finally,N-type and P-type VCTs were successfully fabricated using this implantation method.展开更多
m thin-film fully-depleted SOI CMOS devices with elevated source/drain structure are fabricated by a novel technology.Key process technologies are demonstrated.The devices have quasi-ideal subthreshold properties;the ...m thin-film fully-depleted SOI CMOS devices with elevated source/drain structure are fabricated by a novel technology.Key process technologies are demonstrated.The devices have quasi-ideal subthreshold properties;the subthreshold slope of nMOSFETs is 65mV/decade,while that of pMOSFETs is 69mV/decade.The saturation current of 1.2μm nMOSFETs is increased by 32% with elevated source/drain structure,and that of 1.2μm pMOSFETs is increased by 24%.The per-stage propagation delay of 101-stage fully-depleted SOI CMOS ring oscillator is 75ps with 3V supply voltage.展开更多
Ge complementary tunneling field-effect transistors（TFETs） are fabricated with the NiGe metal source/drain（S/D） structure. The dopant segregation method is employed to form the NiGe/Ge tunneling junctions of suffi...Ge complementary tunneling field-effect transistors（TFETs） are fabricated with the NiGe metal source/drain（S/D） structure. The dopant segregation method is employed to form the NiGe/Ge tunneling junctions of sufficiently high Schottky barrier heights. As a result, the Ge p-and n-TFETs exhibit decent electrical properties of large ON-state current and steep sub-threshold slope（S factor）. Especially, I_d of 0.2 μA/μm is revealed at V_g-V_（th） = V_d = ±0.5 V for Ge pTFETs,with the S factor of 28 mV/dec at 7 K.展开更多
Fin field-effect transistor(FinFET)technology has been introduced to the mainstream complementary metal-oxide semiconductor(CMOS)manufacturing for low-power and highperformance applications.However,advanced FinFET nod...Fin field-effect transistor(FinFET)technology has been introduced to the mainstream complementary metal-oxide semiconductor(CMOS)manufacturing for low-power and highperformance applications.However,advanced FinFET nodes are facing significant challenges to enhance the device performance due to the increasingly prominent parasitic resistance and capacitance.In this study,for the first time,we demonstrate methods of enhancing p-channel FinFET(pFET)performance on a fully integrated advanced FinFET platform via source/drain(S/D)cavity structure optimization.By modulating the cavity depth and proximity around the optimal reference point,we show that the trade-off between the S/D resistance and short channel effect,as well as the impact on the parasitic capacitance must be considered for the S/D cavity structure optimization.An extra process knob of applying cavity implant on the desired cavity structure was also demonstrated to modify the S/D junction profile for device performance enhancement.展开更多
In this paper, we propose a novel Schottky barrier MOSFET structure, in which the silicide source/drain is designed on the buried metal （SSDOM）. The source/drain region consists of two layers of silicide materials. ...In this paper, we propose a novel Schottky barrier MOSFET structure, in which the silicide source/drain is designed on the buried metal （SSDOM）. The source/drain region consists of two layers of silicide materials. Two Schottky barriers are formed between the silicide layers and the silicon channel. In the device design, the top barrier is lower and the bottom is higher. The lower top contact barrier is to provide higher on-state current, and the higher bottom contact barrier to reduce the off-state current. To achieve this, ErSi is proposed for the top silicide and CoSi2 for the bottom in the n-channel ease. The 50 nm n-channel SSDOM is thus simulated to analyse the performance of the SSDOM device. In the simulations, the top contact barrier is 0.2e V （for ErSi） and the bottom barrier is 0.6 eV （for CoSi2）. Compared with the corresponding conventional Schottky barrier MOSFET structures （CSB）, the high on-state current of the SSDOM is maintained, and the off-state current is efficiently reduced. Thus, the high drive ability （1.2 mA/μm at Vds = 1 V, Vgs = 2 V） and the high Ion/Imin ratio （10^6） are both achieved by applying the SSDOM structure.展开更多
In this paper, a surface potential based threshold voltage model of fully-depleted（FD） recessed-source/drain（Re-S/D）silicon-on-insulator（SOI） metal-oxide semiconductor field-effect transistor（MOSFET） is presen...In this paper, a surface potential based threshold voltage model of fully-depleted（FD） recessed-source/drain（Re-S/D）silicon-on-insulator（SOI） metal-oxide semiconductor field-effect transistor（MOSFET） is presented while considering the effects of high-k gate-dielectric material induced fringing-field. The two-dimensional（2D） Poisson＇s equation is solved in a channel region in order to obtain the surface potential under the assumption of the parabolic potential profile in the transverse direction of the channel with appropriate boundary conditions. The accuracy of the model is verified by comparing the model＇s results with the 2D simulation results from ATLAS over a wide range of channel lengths and other parameters,including the dielectric constant of gate-dielectric material.展开更多
We investigate the influence of source and drain bias voltages(V_(DS))on the quantum sub-band transport spectrum in the 10-nm width N-typed junctionless nanowire transistor at the low temperature of 6 K.We demonstrate...We investigate the influence of source and drain bias voltages(V_(DS))on the quantum sub-band transport spectrum in the 10-nm width N-typed junctionless nanowire transistor at the low temperature of 6 K.We demonstrate that the transverse electric field introduced from V_(DS) has a minor influence on the threshold voltage of the device.The transverse electric field plays the role of amplifying the gate restriction effect of the channel.The one-dimensional(1D)-band dominated transport is demonstrated to be modulated by V_(DS) in the saturation region and the linear region,with the sub-band energy levels in the channel(E_(channel))intersecting with Fermi levels of the source(E_(fS))and the drain(E_(fD))in turn as V_(g) increases.The turning points from the linear region to the saturation region shift to higher gate voltages with V_(DS) increase because the higher Fermi energy levels of the channel required to meet the situation of E_(fD)=E_(channel).We also find that the bias electric field has the effect to accelerate the thermally activated electrons in the channel,equivalent to the effect of thermal temperature on the increase of electron energy.Our work provides a detailed description of the bias-modulated quantum electronic properties,which will give a more comprehensive understanding of transport behavior in nanoscale devices.展开更多
GaSb is an attractive candidate for future high-performance Ⅲ-Ⅴ p-channel metal-oxide-semiconductor-field-effect-transistors(pMOSFETs)because of its high hole mobility.The effect of HCl based-chemical cleaning on re...GaSb is an attractive candidate for future high-performance Ⅲ-Ⅴ p-channel metal-oxide-semiconductor-field-effect-transistors(pMOSFETs)because of its high hole mobility.The effect of HCl based-chemical cleaning on removing the non-self limiting and instable native oxide layer of GaSb to obtain a clean and smooth surface has been studied.It is observed that the rms roughness of a GaSb surface is significantly reduced from 2.731 nm to 0.693 nm by using HCl:H_(2)O(1:3)solution.The Ni/Pt/Au ohmic contact exhibits an optimal specific contact resistivity of about 6.89×10^(-7)Ω·cm^(2) with a 60 s rapid thermal anneal(RTA)at 250℃.Based on the chemical cleaning and ohmic contact experimental results,inversion-channel enhancement GaSb pMOSFETs are demonstrated.For a 6μm gate length GaSb pMOSFET,a maximum drain current of about 4.0 mA/mm,a drain current on-off(ION/IOFF)ratio of>10^(3),and a subthreshold swing of~250 mV/decade are achieved.Combined with the split C-V method,a peak hole mobility of about 160 cm^(2)/V·s is obtained for a 24μm gate length GaSb pMOSFET.展开更多
A dual silicide layer structure is proposed for Schottky barrier metal-oxide-semiconductor held effect transistors(MOSFETs)on bulk substrates.The source/drain regions are designed to be composed with dual stacked sili...A dual silicide layer structure is proposed for Schottky barrier metal-oxide-semiconductor held effect transistors(MOSFETs)on bulk substrates.The source/drain regions are designed to be composed with dual stacked silicide layers,forming different barrier heights to silicon channel.Performance comparisons between the dual barrier structure and the single barrier structure are carried out with numerical simulations.It is found that the dual barrier structure has significant advantages over the single barrier structure because the drive current and leakage current of the dual barrier structure can be modulated.Furthermore,the dual barrier structure's performance is nearly insensitive to the total silicide thickness,which can relax the fabrication requirements and even make an SOI substrate unnecessary for planar device design.The formation of ErSix/CoSi2 stacked multilayers has been proved by experiments.展开更多
39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.Ar...39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.ArcGIS inverse distance weight difference method was used to analyze the characteristics of pollution distribution,and single-factor pollution index,Nemerow comprehensive pollution index,ground accumulation index,and potential ecological risk index were selected to evaluate the characteristics of heavy metal pollution.Based on correlation analysis,the absolute principal component-multiple linear regression(APCS-MLR)and positive definite matrix factorization(PMF)models were used to analyze the sources of soil heavy metals.The results showed that the average concentrations of all eight heavy metals exceeded both national and Guangxi soil background values.Hg,Cd,and Zn exhibited high variation(greater than 0.5),indicating significant external disturbances,and their spatial distribution was closely related to mining activity locations.The single-factor pollution index evaluation indicated varying degrees of pollution risk for Cd,Zn,and As,with Cd and Zn being the most severe pollutants,as 69.23%and 30.77%of the samples fell into the moderate pollution or higher category.The geoaccumulation index analysis ranked the mean pollution levels of the eight elements as follows:Zn>Cd>Ni>Pb>Cu>Cr>Hg>As,with Cd and Zn showing the most severe contamination,and 51.28%of the samples exhibiting moderate or higher pollution levels.The Nemerow comprehensive pollution index evaluation showed that 74.35%of soil samples were classified as moderate to heavy pollution.The potential ecological risk index assessment indicated significant ecological risks posed by Cd and Zn,with 82.05%and 5.12%of the samples classified as causing strong to extreme ecological risks,respectively.The source apportionment analysis revealed minor differences between the two models.The APCS-MLR model identified three pollution sources and their contribution rates:anthropogenic mining sources(31.13%),parent material sources(40.38%),and unidentified sources(28.49%).The PMF model identified three pollution sources with contribution rates of anthropogenic mining sources(26.10%),parent material sources(46.96%),and a combined traffic and agricultural source(26.61%).Pb,Hg,Cd,and Zn mainly originated from mining activities;Cr,As,and Ni were primarily derived from the parent material,while Cu was predominantly attributed to traffic and agricultural sources.These findings provide a scientific basis for the prevention and control of heavy metal pollution in mining areas.展开更多
The present study investigated the effects of varying protein source combinations and feeding strategies on the growth,health and organoleptic quality of the large yellow croaker(Larimichthys crocea).Three iso-nitroge...The present study investigated the effects of varying protein source combinations and feeding strategies on the growth,health and organoleptic quality of the large yellow croaker(Larimichthys crocea).Three iso-nitrogenous and iso-lipidic diets were formulated.The control diet was made with 62%fish meal(FM).The other two experimental diets were formulated by replacing 45%FM with 22.5%mealworm(TM)and 22.5%cottonseed protein concentrate(CPC),or with 22.5%TM and 22.5%Clostridium autoethanogenum protein(CAP),respectively.The three kinds of diet were named as A1,A2 and A3,respectively.Five groups of large yellow croaker were fed with two different strategies:the first three groups were continuously fed with A1,A2 and A3 diets,respectively.The fourth group was alternately fed with A1 and A2 diet every 5 days.The fifth group was alternately fed with A1 and A3diet every 5 days.The five groups were named D1,D2,D3,D1-2 and D1-3,respectively.Results showed that D2 and D3 groups exhibited significantly lower weight gain rate(WGR)and higher feed conversion ratios(FCR)compared to the D1 group.The D1-2 and D1-3 groups exhibited improved WGR and significantly reduced FCR compared to the D2 and D3 groups.The A2 and A3 diets significantly suppressed digestive enzymes'activities compared to A1,whereas alternate-feeding groups significantly enhanced the enzyme activities.Compared to the D1 group,D2 and D3 groups significantly downregulated mRNA expression levels of intestinal antiinflammatory cytokines and upregulated the expression of pro-inflammatory mediators.The anti-inflammatory abilities in the D1-2and D1-3 groups were significantly higher than those in the D2 and D3 groups.Additionally,diets containing TM+CAP and TM+CPC protein sources enhanced ventral redness and yellowness indices.Considering the growth,digestion,immunity and organoleptic quality of large yellow croaker,it is recommended to replace up to 45%of FM with TM+CPC and use an alternate-feeding strategy.展开更多
Presented in this study is a novel method for estimating the depth of single underwater source in shallow water,utilizing vector sensors.The approach leverages the depth distribution of the broadband Stokes parameters...Presented in this study is a novel method for estimating the depth of single underwater source in shallow water,utilizing vector sensors.The approach leverages the depth distribution of the broadband Stokes parameters to estimate source depth accurately.Unlike traditional matched field processing(MFP)and matched mode processing(MMP),the proposed approach can estimate source depth directly from the data received by sensors without requiring complete environmental information.Firstly,the broadband Stokes parameters(BSP)are established using the normal mode theory.Then the nonstationary phase approximation is used to simplify the theoretical derivation,which is necessary when dealing with broadband integrals.Additionally,range terms of the BSP are eliminated by normalization.By analyzing the depth distribution of the normalized broadband Stokes parameters(NBSP),it is found that the NBSP exhibit extreme values at the source depth,which can be used for source depth estimation.So the proposed depth estimation method is based on searching the peaks of the NBSP.Simulations show that this method is effective in relatively simple shallow water environments.Finally,the effect of source range,frequency bandwidth,sound speed profile(SSP),water depth,and signal-to-noise ratio(SNR)are studied.The findings indicate that the proposed method can accurately estimate the source depth when the SNR is greater than-5 d B and does not need to consider model mismatch issues.Additionally,variations in environmental parameters have minimal impact on estimation accuracy.Compared to MFP,the proposed method requires a higher SNR,but demonstrates superior robustness against fluctuations in environmental parameters.展开更多
The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,...The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,despite the fact that the scenario exists in practice.A series of laboratory-scale experiments were conducted in this study to investigate the smoke back-layering length in a model tunnel with cross-passage.The heat release rate,the velocity of longitudinal air flow,and the location of the fire source were all varied.It was found that the behavior of smoke backflow for the fire source located at the upstream of bifurcation point resembles a single-hole tunnel fire.As the fire source’s position shifts downstream from the bifurcation point,the length of smoke back-layering progressively increases.A competitive interaction exists between airflow diversion and smoke diversion during smoke backflow,significantly affecting the smoke back-layering length in the main tunnel.The dimensionless smoke back-layering length model was formulated in a tunnel featuring a cross-passage,taking into account the positions of longitudinal fire sources.The dimensionless smoke back-layering length exhibits a positive correlation with the 17/18 power of total heat release rate Q and a negative correlation with the 5/2 power of longitudinal ventilation velocity V.展开更多
This study examined a case of ventilator-associated pneumonia caused by Ralstonia mannitolilytica in a neonatal department in order to determine the source of infection and mode of transmission.Symptoms of infection b...This study examined a case of ventilator-associated pneumonia caused by Ralstonia mannitolilytica in a neonatal department in order to determine the source of infection and mode of transmission.Symptoms of infection began to appear on day 16 of admission,and both sputum and catheter tip cultures revealed R.mannitolilytica.The infection control department of the hospital later sampled and identified R.mannitolilytica in the ventilator tube that was used by the patient with the exact gene sequence as the infecting strain.These findings indicate that ventilator tubing is a significant contamination source of this pathogen,and hospitals need to enhance their disinfection methods of ventilator-related devices.展开更多
The complexity of the seismicity pattern for the subduction zone along the oceanic plate triggered the outer rise events and revealed cyclic tectonic deformation conditions along the plate subduction zones.The outer r...The complexity of the seismicity pattern for the subduction zone along the oceanic plate triggered the outer rise events and revealed cyclic tectonic deformation conditions along the plate subduction zones.The outer rise earthquakes have been observed along the Sunda arc,following the estimated rupture area of the 2005 M_(W)8.6 Nias earthquakes.Here,we used kinematic waveform inversion(KIWI)to obtain the source parameters of the 14 May 2021 M_(W)6.6 event off the west coast of northern Sumatra and to define the fault plane that triggered this outer rise event.The KIWI algorithm allows two types of seismic source to be configured:the moment tensor model to describe the type of shear with six moment tensor components and the Eikonal model for the rupture of pure double-couple sources.This method was chosen for its flexibility to be applied for different sources of seismicity and also for the automated full-moment tensor solution with real-time monitoring.We used full waveform traces from 8 broadband seismic stations within 1000 km epicentral distances sourced from the Incorporated Research Institutions for Seismology(IRIS-IDA)and Geofon GFZ seismic record databases.The initial origin time and hypocenter values are obtained from the IRIS-IDA.The synthetic seismograms used in the inversion process are based on the existing regional green function database model and were accessed from the KIWI Tools Green's Function Database.The obtained scalar seismic moment value is 1.18×10^(19)N·m,equivalent to a moment magnitude M_(W)6.6.The source parameters are 140°,44°,and−99°for the strike,dip,and rake values at a centroid depth of 10.2 km,indicating that this event is a normal fault earthquake that occurred in the outer rise area.The outer rise events with normal faults typically occur at the shallow part of the plate,with nodal-plane dips predominantly in the range of 30°-60°on the weak oceanic lithosphere due to hydrothermal alteration.The stress regime around the plate subduction zone varies both temporally and spatially due to the cyclic influences of megathrust earthquakes.Tensional outer rise earthquakes tend to occur after the megathrust events.The relative timing of these events is not known due to the viscous relaxation of the down going slab and poroelastic response in the trench slope region.The occurrence of the 14 May 2021 earthquake shows the seismicity in the outer rise region in the strongly coupled Sunda arc subduction zone due to elastic bending stress within the duration of the seismic cycle.展开更多
Nitrogen(N)and phosphorus(P)are essential nutrients and can significantly impact primary productivity of the ecosystem causing water environmental problems.However,their cycling mechanisms are not well understood in a...Nitrogen(N)and phosphorus(P)are essential nutrients and can significantly impact primary productivity of the ecosystem causing water environmental problems.However,their cycling mechanisms are not well understood in alpine mountains with climate change.Hence,94 samples of river water were collected from 2018 to 2020 in the headwaters of the Shule River Basin to assess the nutrients spatiotemporal distribution and combined ap-proach of water quality index to assess water quality and potential sources.The findings depict that high nutrient concentrations were found to coincide with snowmelt and glacial meltwater and rainfall recharge periods,while total flux peaked from June to September due to increased runoff.Notably,total nitrogen(TN)concentrations were significantly higher near the town,primarily attributed to the replenishment of nitrate(NO_(3)^(‒)-N)from live-stock manure.The high total P(TP)was near the glacier,which was attributed to the transportation of glacial sediments into the river,and pH was another critical factor.N was the primary nutrient limiting factor for the growth of phytoplankton in river water.Although the migration and transport of nutrients have altered with climate change,river water quality is good in alpine mountains based on an overall evaluation.These findings contribute to enriching nutrient datasets and highlight the importance of water resource management and water quality assessment in sensitive and fragile alpine mountains.展开更多
The Southern Advanced Photon Source(SAPS)is a diffraction-limited synchrotron light source under design,which employs longitudinal injection as its primary injection scheme.This kind of injection scheme requires that ...The Southern Advanced Photon Source(SAPS)is a diffraction-limited synchrotron light source under design,which employs longitudinal injection as its primary injection scheme.This kind of injection scheme requires that the injected beam has a short bunch length and low emittance,and the preferred injector should offer high stability and low cost.Therefore,an injector based on a booster synchrotron was developed.The proposed injector includes a 250 MeV linac,a booster synchrotron that ramps the beam energy to 3.5 GeV,and two beam transport lines to ensure efficient beam delivery and beam quality preservation.The linac utilizes a thermionic high-voltage DC gun for reliable operation and features a bunching system with an advanced focusing system to preserve the emittance.To meet the injection requirements of the SAPS,a comprehensive design for the booster has been conducted.The booster synchrotron employs a threefold lattice structure,incorporating modified theoretical minimum emittance cells with a small momentum compaction factor and a high voltage to achieve an emittance of 3.98 nm rad and a bunch length of 4.8 mm.The injector has the potential to deliver a high charge,reducing the injection period of the storage ring to less than 1 min.Simulations demonstrated the expected performance,with a transmission efficiency of 90%,confirming its capability to meet the injection requirement of the SAPS storage ring.This design offers a stable and efficient solution for the SAPS.展开更多
We present the preparation and measurement of the radioactive isotope^(37)Ar,which was produced using thermal neutrons from a reactor,as a calibration source for liquid xenon time projection chambers.^(37)Ar is a low-...We present the preparation and measurement of the radioactive isotope^(37)Ar,which was produced using thermal neutrons from a reactor,as a calibration source for liquid xenon time projection chambers.^(37)Ar is a low-energy calibration source with a half-life of 35.01 days,making it suitable for calibration in the low-energy region of liquid xenon dark-matter experiments.Radioactive isotope^(37)Ar was produced by irradiating ^(36)Ar with thermal neutrons.It was subsequently measured in a gaseous xenon time projection chamber(GXe TPC)to validate its radioactivity.Our results demonstrate that^(37)Ar is an effective and viable calibration source that offers precise calibration capabilities in the low-energy domain of xenon-based detectors.展开更多
In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly...In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly(effectively imposing a wavelet-spectrum weighting,often akin to an amplitude-squared bias).This redundancy degrades structural fidelity and amplitude balance yet is frequently overlooked.We(i)formalize the mechanism by which cross-correlation duplicates the source-wavelet amplitude effect in both migration and demigration,and(ii)introduce a source-equalized operator that removes the redundancy by deconvolving(or dividing by)the wavelet amplitude spectrum in the imaging condition and its demigration counterpart,while leaving phase/kinematics intact.Using a band-limited Ricker wavelet on a two-layer model and on Marmousi,we show that,if unmanaged,the redundant wavelet spectrum broadens main lobes,introduces ringing,and suppresses vertical resolution in migrated images,and inflates spectrum mismatches between demigrated and observed data even when peak times agree.With our correction,images recover observed-data-consistent bandwidth and sharpened interfaces,and demigrated data also exhibit improved spectrum conformity and reduced amplitude misfit.The results clarify when source amplitudes matter,why cross-correlation makes them redundantly matter,and how a lightweight spectral correction restores physically meaningful amplitude behavior in wave-equation migration/demigration.展开更多
We conducted a field campaign to investigate the chemical composition,sources,and light absorption of submicron aerosols(PM_(1))from early 2022 in Nanjing,China.The average concentration of PM_(1) was 31μg m^(−3),org...We conducted a field campaign to investigate the chemical composition,sources,and light absorption of submicron aerosols(PM_(1))from early 2022 in Nanjing,China.The average concentration of PM_(1) was 31μg m^(−3),organics(33%)constituted the largest fraction,followed by nitrate(30%),sulfate(18%),ammonium(15%),chloride(3%),and rBC(2%).Four organic aerosol(OA)subcomponents were identified,including two primary OA(POA)and two secondary OA(SOA).The less-oxidized SOA(LO-OOA)contributes the most to the total OA mass(59%).LO-OOA is tightly correlated with the tracer ion C_(2)H_(4)O_(2)^(+)from levoglucosan,and another aged biomass-burning derived species,K_(3)SO_(4)^(+),suggesting it was likely influenced by aged biomass-burning OA.Our study also revealed that fireworks during the Spring Festival have a detrimental impact on air quality,contributing to secondary formation and accumulation under static winter meteorological conditions,prolonging the pollution duration.Also,LO-OOA was found to have the strongest light-absorbing ability.Our results highlight that the light absorption of LO-OOA can mainly be attributed to the C_(x)H_(y)N^(+) family,increased with the double-bond equivalent value.The more-oxidized SOA(MO-OOA)exhibited a negligible light absorption and was strongly correlated with daytime photochemical processes,implying a light-bleaching effect.This study enhances our understanding of the regional contribution of biomass combustion and fireworks to PM_(1) pollution in Nanjing,a typical megacity in the Yangtze River Delta region,during winter,aiding in the development of strategies for long-term air quality improvement in the region.展开更多
文摘In vertical channel transistors(VCTs),source/drain ion implantation(I/I)represents a significant technical challenge due to inherent three-dimensional structural constraints,which induce complications such as difficulties in dummy gate forma-tion and shadowing effects of I/I.This article systematically investigates the impact of different implantation conditions on the performance of VCTs with and without dummy gates through TCAD simulation.It reveals the significant role of the lightly doped regions(LDRs)naturally formed due to ion implantation in source/drain of VCTs.Furthermore,it was found that VCT with-out dummy gates can achieve an approximately 27%increase in on-state current(Ion)under the same implantation conditions,and can greatly simplify the process flow and reduce costs.Finally,N-type and P-type VCTs were successfully fabricated using this implantation method.
文摘m thin-film fully-depleted SOI CMOS devices with elevated source/drain structure are fabricated by a novel technology.Key process technologies are demonstrated.The devices have quasi-ideal subthreshold properties;the subthreshold slope of nMOSFETs is 65mV/decade,while that of pMOSFETs is 69mV/decade.The saturation current of 1.2μm nMOSFETs is increased by 32% with elevated source/drain structure,and that of 1.2μm pMOSFETs is increased by 24%.The per-stage propagation delay of 101-stage fully-depleted SOI CMOS ring oscillator is 75ps with 3V supply voltage.
基金Supported by the National Natural Science Foundation of China under Grant No 61504120the Zhejiang Provincial Natural Science Foundation of China under Grant No LR18F040001the Fundamental Research Funds for the Central Universities
文摘Ge complementary tunneling field-effect transistors（TFETs） are fabricated with the NiGe metal source/drain（S/D） structure. The dopant segregation method is employed to form the NiGe/Ge tunneling junctions of sufficiently high Schottky barrier heights. As a result, the Ge p-and n-TFETs exhibit decent electrical properties of large ON-state current and steep sub-threshold slope（S factor）. Especially, I_d of 0.2 μA/μm is revealed at V_g-V_（th） = V_d = ±0.5 V for Ge pTFETs,with the S factor of 28 mV/dec at 7 K.
文摘Fin field-effect transistor(FinFET)technology has been introduced to the mainstream complementary metal-oxide semiconductor(CMOS)manufacturing for low-power and highperformance applications.However,advanced FinFET nodes are facing significant challenges to enhance the device performance due to the increasingly prominent parasitic resistance and capacitance.In this study,for the first time,we demonstrate methods of enhancing p-channel FinFET(pFET)performance on a fully integrated advanced FinFET platform via source/drain(S/D)cavity structure optimization.By modulating the cavity depth and proximity around the optimal reference point,we show that the trade-off between the S/D resistance and short channel effect,as well as the impact on the parasitic capacitance must be considered for the S/D cavity structure optimization.An extra process knob of applying cavity implant on the desired cavity structure was also demonstrated to modify the S/D junction profile for device performance enhancement.
基金Project supported by the National Natural Science Foundation of China （Grant No 60506009）.
文摘In this paper, we propose a novel Schottky barrier MOSFET structure, in which the silicide source/drain is designed on the buried metal （SSDOM）. The source/drain region consists of two layers of silicide materials. Two Schottky barriers are formed between the silicide layers and the silicon channel. In the device design, the top barrier is lower and the bottom is higher. The lower top contact barrier is to provide higher on-state current, and the higher bottom contact barrier to reduce the off-state current. To achieve this, ErSi is proposed for the top silicide and CoSi2 for the bottom in the n-channel ease. The 50 nm n-channel SSDOM is thus simulated to analyse the performance of the SSDOM device. In the simulations, the top contact barrier is 0.2e V （for ErSi） and the bottom barrier is 0.6 eV （for CoSi2）. Compared with the corresponding conventional Schottky barrier MOSFET structures （CSB）, the high on-state current of the SSDOM is maintained, and the off-state current is efficiently reduced. Thus, the high drive ability （1.2 mA/μm at Vds = 1 V, Vgs = 2 V） and the high Ion/Imin ratio （10^6） are both achieved by applying the SSDOM structure.
基金supported by the Science and Engineering Research Board(SERB),Department of Science and Technology,Ministry of Human Resource and Development,Government of India under Young Scientist Research(Grant No.SB/FTP/ETA-415/2012)
文摘In this paper, a surface potential based threshold voltage model of fully-depleted（FD） recessed-source/drain（Re-S/D）silicon-on-insulator（SOI） metal-oxide semiconductor field-effect transistor（MOSFET） is presented while considering the effects of high-k gate-dielectric material induced fringing-field. The two-dimensional（2D） Poisson＇s equation is solved in a channel region in order to obtain the surface potential under the assumption of the parabolic potential profile in the transverse direction of the channel with appropriate boundary conditions. The accuracy of the model is verified by comparing the model＇s results with the 2D simulation results from ATLAS over a wide range of channel lengths and other parameters,including the dielectric constant of gate-dielectric material.
基金the National Key Research and Development Program of China(Grant No.2016YFA0200503).
文摘We investigate the influence of source and drain bias voltages(V_(DS))on the quantum sub-band transport spectrum in the 10-nm width N-typed junctionless nanowire transistor at the low temperature of 6 K.We demonstrate that the transverse electric field introduced from V_(DS) has a minor influence on the threshold voltage of the device.The transverse electric field plays the role of amplifying the gate restriction effect of the channel.The one-dimensional(1D)-band dominated transport is demonstrated to be modulated by V_(DS) in the saturation region and the linear region,with the sub-band energy levels in the channel(E_(channel))intersecting with Fermi levels of the source(E_(fS))and the drain(E_(fD))in turn as V_(g) increases.The turning points from the linear region to the saturation region shift to higher gate voltages with V_(DS) increase because the higher Fermi energy levels of the channel required to meet the situation of E_(fD)=E_(channel).We also find that the bias electric field has the effect to accelerate the thermally activated electrons in the channel,equivalent to the effect of thermal temperature on the increase of electron energy.Our work provides a detailed description of the bias-modulated quantum electronic properties,which will give a more comprehensive understanding of transport behavior in nanoscale devices.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CBA00605,2010CB327501the National Natural Science Foundation of China under Grant No 61106095+1 种基金the National Science&Technology Major Project of China under Grant No 2011ZX02708-003One Hundred Talents Program of Chinese Academy of Sciences,and the Scientific Research Foundation for the Returned Overseas Chinese Scholars,the Ministry of Education of China.
文摘GaSb is an attractive candidate for future high-performance Ⅲ-Ⅴ p-channel metal-oxide-semiconductor-field-effect-transistors(pMOSFETs)because of its high hole mobility.The effect of HCl based-chemical cleaning on removing the non-self limiting and instable native oxide layer of GaSb to obtain a clean and smooth surface has been studied.It is observed that the rms roughness of a GaSb surface is significantly reduced from 2.731 nm to 0.693 nm by using HCl:H_(2)O(1:3)solution.The Ni/Pt/Au ohmic contact exhibits an optimal specific contact resistivity of about 6.89×10^(-7)Ω·cm^(2) with a 60 s rapid thermal anneal(RTA)at 250℃.Based on the chemical cleaning and ohmic contact experimental results,inversion-channel enhancement GaSb pMOSFETs are demonstrated.For a 6μm gate length GaSb pMOSFET,a maximum drain current of about 4.0 mA/mm,a drain current on-off(ION/IOFF)ratio of>10^(3),and a subthreshold swing of~250 mV/decade are achieved.Combined with the split C-V method,a peak hole mobility of about 160 cm^(2)/V·s is obtained for a 24μm gate length GaSb pMOSFET.
基金Supported by the National Natural Science Foundation of China(No.61474005)the Beijing Natural Science Foundation(No.4182025)。
文摘A dual silicide layer structure is proposed for Schottky barrier metal-oxide-semiconductor held effect transistors(MOSFETs)on bulk substrates.The source/drain regions are designed to be composed with dual stacked silicide layers,forming different barrier heights to silicon channel.Performance comparisons between the dual barrier structure and the single barrier structure are carried out with numerical simulations.It is found that the dual barrier structure has significant advantages over the single barrier structure because the drive current and leakage current of the dual barrier structure can be modulated.Furthermore,the dual barrier structure's performance is nearly insensitive to the total silicide thickness,which can relax the fabrication requirements and even make an SOI substrate unnecessary for planar device design.The formation of ErSix/CoSi2 stacked multilayers has been proved by experiments.
文摘39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.ArcGIS inverse distance weight difference method was used to analyze the characteristics of pollution distribution,and single-factor pollution index,Nemerow comprehensive pollution index,ground accumulation index,and potential ecological risk index were selected to evaluate the characteristics of heavy metal pollution.Based on correlation analysis,the absolute principal component-multiple linear regression(APCS-MLR)and positive definite matrix factorization(PMF)models were used to analyze the sources of soil heavy metals.The results showed that the average concentrations of all eight heavy metals exceeded both national and Guangxi soil background values.Hg,Cd,and Zn exhibited high variation(greater than 0.5),indicating significant external disturbances,and their spatial distribution was closely related to mining activity locations.The single-factor pollution index evaluation indicated varying degrees of pollution risk for Cd,Zn,and As,with Cd and Zn being the most severe pollutants,as 69.23%and 30.77%of the samples fell into the moderate pollution or higher category.The geoaccumulation index analysis ranked the mean pollution levels of the eight elements as follows:Zn>Cd>Ni>Pb>Cu>Cr>Hg>As,with Cd and Zn showing the most severe contamination,and 51.28%of the samples exhibiting moderate or higher pollution levels.The Nemerow comprehensive pollution index evaluation showed that 74.35%of soil samples were classified as moderate to heavy pollution.The potential ecological risk index assessment indicated significant ecological risks posed by Cd and Zn,with 82.05%and 5.12%of the samples classified as causing strong to extreme ecological risks,respectively.The source apportionment analysis revealed minor differences between the two models.The APCS-MLR model identified three pollution sources and their contribution rates:anthropogenic mining sources(31.13%),parent material sources(40.38%),and unidentified sources(28.49%).The PMF model identified three pollution sources with contribution rates of anthropogenic mining sources(26.10%),parent material sources(46.96%),and a combined traffic and agricultural source(26.61%).Pb,Hg,Cd,and Zn mainly originated from mining activities;Cr,As,and Ni were primarily derived from the parent material,while Cu was predominantly attributed to traffic and agricultural sources.These findings provide a scientific basis for the prevention and control of heavy metal pollution in mining areas.
基金financially supported by the Key Research and Development Program of Shandong,China(No.2021SFGC0701)。
文摘The present study investigated the effects of varying protein source combinations and feeding strategies on the growth,health and organoleptic quality of the large yellow croaker(Larimichthys crocea).Three iso-nitrogenous and iso-lipidic diets were formulated.The control diet was made with 62%fish meal(FM).The other two experimental diets were formulated by replacing 45%FM with 22.5%mealworm(TM)and 22.5%cottonseed protein concentrate(CPC),or with 22.5%TM and 22.5%Clostridium autoethanogenum protein(CAP),respectively.The three kinds of diet were named as A1,A2 and A3,respectively.Five groups of large yellow croaker were fed with two different strategies:the first three groups were continuously fed with A1,A2 and A3 diets,respectively.The fourth group was alternately fed with A1 and A2 diet every 5 days.The fifth group was alternately fed with A1 and A3diet every 5 days.The five groups were named D1,D2,D3,D1-2 and D1-3,respectively.Results showed that D2 and D3 groups exhibited significantly lower weight gain rate(WGR)and higher feed conversion ratios(FCR)compared to the D1 group.The D1-2 and D1-3 groups exhibited improved WGR and significantly reduced FCR compared to the D2 and D3 groups.The A2 and A3 diets significantly suppressed digestive enzymes'activities compared to A1,whereas alternate-feeding groups significantly enhanced the enzyme activities.Compared to the D1 group,D2 and D3 groups significantly downregulated mRNA expression levels of intestinal antiinflammatory cytokines and upregulated the expression of pro-inflammatory mediators.The anti-inflammatory abilities in the D1-2and D1-3 groups were significantly higher than those in the D2 and D3 groups.Additionally,diets containing TM+CAP and TM+CPC protein sources enhanced ventral redness and yellowness indices.Considering the growth,digestion,immunity and organoleptic quality of large yellow croaker,it is recommended to replace up to 45%of FM with TM+CPC and use an alternate-feeding strategy.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12274348 and 12004335)the National Key Research and Development Program of China(Grant No.2024YFC2813800)。
文摘Presented in this study is a novel method for estimating the depth of single underwater source in shallow water,utilizing vector sensors.The approach leverages the depth distribution of the broadband Stokes parameters to estimate source depth accurately.Unlike traditional matched field processing(MFP)and matched mode processing(MMP),the proposed approach can estimate source depth directly from the data received by sensors without requiring complete environmental information.Firstly,the broadband Stokes parameters(BSP)are established using the normal mode theory.Then the nonstationary phase approximation is used to simplify the theoretical derivation,which is necessary when dealing with broadband integrals.Additionally,range terms of the BSP are eliminated by normalization.By analyzing the depth distribution of the normalized broadband Stokes parameters(NBSP),it is found that the NBSP exhibit extreme values at the source depth,which can be used for source depth estimation.So the proposed depth estimation method is based on searching the peaks of the NBSP.Simulations show that this method is effective in relatively simple shallow water environments.Finally,the effect of source range,frequency bandwidth,sound speed profile(SSP),water depth,and signal-to-noise ratio(SNR)are studied.The findings indicate that the proposed method can accurately estimate the source depth when the SNR is greater than-5 d B and does not need to consider model mismatch issues.Additionally,variations in environmental parameters have minimal impact on estimation accuracy.Compared to MFP,the proposed method requires a higher SNR,but demonstrates superior robustness against fluctuations in environmental parameters.
基金funded by the National Natural Science Foundation of China(NSFC)under Grant No.52278415the National Key Research and Development Program of China under Grant No.2022YFC3801104+2 种基金Hebei Provincial Department of Education Project under Grant No.QN2025304the Innovation Fund Project of Hebei University of Engineering under Grant No.SJ2401002066the Sichuan Science and Technology Program under Grant No.2023YFS0407。
文摘The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,despite the fact that the scenario exists in practice.A series of laboratory-scale experiments were conducted in this study to investigate the smoke back-layering length in a model tunnel with cross-passage.The heat release rate,the velocity of longitudinal air flow,and the location of the fire source were all varied.It was found that the behavior of smoke backflow for the fire source located at the upstream of bifurcation point resembles a single-hole tunnel fire.As the fire source’s position shifts downstream from the bifurcation point,the length of smoke back-layering progressively increases.A competitive interaction exists between airflow diversion and smoke diversion during smoke backflow,significantly affecting the smoke back-layering length in the main tunnel.The dimensionless smoke back-layering length model was formulated in a tunnel featuring a cross-passage,taking into account the positions of longitudinal fire sources.The dimensionless smoke back-layering length exhibits a positive correlation with the 17/18 power of total heat release rate Q and a negative correlation with the 5/2 power of longitudinal ventilation velocity V.
文摘This study examined a case of ventilator-associated pneumonia caused by Ralstonia mannitolilytica in a neonatal department in order to determine the source of infection and mode of transmission.Symptoms of infection began to appear on day 16 of admission,and both sputum and catheter tip cultures revealed R.mannitolilytica.The infection control department of the hospital later sampled and identified R.mannitolilytica in the ventilator tube that was used by the patient with the exact gene sequence as the infecting strain.These findings indicate that ventilator tubing is a significant contamination source of this pathogen,and hospitals need to enhance their disinfection methods of ventilator-related devices.
基金supported by the National Natural Science Foundation of China(Grant No.42130312)。
文摘The complexity of the seismicity pattern for the subduction zone along the oceanic plate triggered the outer rise events and revealed cyclic tectonic deformation conditions along the plate subduction zones.The outer rise earthquakes have been observed along the Sunda arc,following the estimated rupture area of the 2005 M_(W)8.6 Nias earthquakes.Here,we used kinematic waveform inversion(KIWI)to obtain the source parameters of the 14 May 2021 M_(W)6.6 event off the west coast of northern Sumatra and to define the fault plane that triggered this outer rise event.The KIWI algorithm allows two types of seismic source to be configured:the moment tensor model to describe the type of shear with six moment tensor components and the Eikonal model for the rupture of pure double-couple sources.This method was chosen for its flexibility to be applied for different sources of seismicity and also for the automated full-moment tensor solution with real-time monitoring.We used full waveform traces from 8 broadband seismic stations within 1000 km epicentral distances sourced from the Incorporated Research Institutions for Seismology(IRIS-IDA)and Geofon GFZ seismic record databases.The initial origin time and hypocenter values are obtained from the IRIS-IDA.The synthetic seismograms used in the inversion process are based on the existing regional green function database model and were accessed from the KIWI Tools Green's Function Database.The obtained scalar seismic moment value is 1.18×10^(19)N·m,equivalent to a moment magnitude M_(W)6.6.The source parameters are 140°,44°,and−99°for the strike,dip,and rake values at a centroid depth of 10.2 km,indicating that this event is a normal fault earthquake that occurred in the outer rise area.The outer rise events with normal faults typically occur at the shallow part of the plate,with nodal-plane dips predominantly in the range of 30°-60°on the weak oceanic lithosphere due to hydrothermal alteration.The stress regime around the plate subduction zone varies both temporally and spatially due to the cyclic influences of megathrust earthquakes.Tensional outer rise earthquakes tend to occur after the megathrust events.The relative timing of these events is not known due to the viscous relaxation of the down going slab and poroelastic response in the trench slope region.The occurrence of the 14 May 2021 earthquake shows the seismicity in the outer rise region in the strongly coupled Sunda arc subduction zone due to elastic bending stress within the duration of the seismic cycle.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0208)the National Natural Science Foundation of China(Nos.42171148 and 42330512)the Key R&D Project from the Science and Technology Department of Tibet(No.XZ202501ZY0030).
文摘Nitrogen(N)and phosphorus(P)are essential nutrients and can significantly impact primary productivity of the ecosystem causing water environmental problems.However,their cycling mechanisms are not well understood in alpine mountains with climate change.Hence,94 samples of river water were collected from 2018 to 2020 in the headwaters of the Shule River Basin to assess the nutrients spatiotemporal distribution and combined ap-proach of water quality index to assess water quality and potential sources.The findings depict that high nutrient concentrations were found to coincide with snowmelt and glacial meltwater and rainfall recharge periods,while total flux peaked from June to September due to increased runoff.Notably,total nitrogen(TN)concentrations were significantly higher near the town,primarily attributed to the replenishment of nitrate(NO_(3)^(‒)-N)from live-stock manure.The high total P(TP)was near the glacier,which was attributed to the transportation of glacial sediments into the river,and pH was another critical factor.N was the primary nutrient limiting factor for the growth of phytoplankton in river water.Although the migration and transport of nutrients have altered with climate change,river water quality is good in alpine mountains based on an overall evaluation.These findings contribute to enriching nutrient datasets and highlight the importance of water resource management and water quality assessment in sensitive and fragile alpine mountains.
基金supported by the Guangdong Basic and Applied Basic Research Foundation,China(No.2021B1515140007).
文摘The Southern Advanced Photon Source(SAPS)is a diffraction-limited synchrotron light source under design,which employs longitudinal injection as its primary injection scheme.This kind of injection scheme requires that the injected beam has a short bunch length and low emittance,and the preferred injector should offer high stability and low cost.Therefore,an injector based on a booster synchrotron was developed.The proposed injector includes a 250 MeV linac,a booster synchrotron that ramps the beam energy to 3.5 GeV,and two beam transport lines to ensure efficient beam delivery and beam quality preservation.The linac utilizes a thermionic high-voltage DC gun for reliable operation and features a bunching system with an advanced focusing system to preserve the emittance.To meet the injection requirements of the SAPS,a comprehensive design for the booster has been conducted.The booster synchrotron employs a threefold lattice structure,incorporating modified theoretical minimum emittance cells with a small momentum compaction factor and a high voltage to achieve an emittance of 3.98 nm rad and a bunch length of 4.8 mm.The injector has the potential to deliver a high charge,reducing the injection period of the storage ring to less than 1 min.Simulations demonstrated the expected performance,with a transmission efficiency of 90%,confirming its capability to meet the injection requirement of the SAPS storage ring.This design offers a stable and efficient solution for the SAPS.
基金supported by National Key R&D grant from the Ministry of Science and Technology of China(Nos.2021YFA1601600,2023YFA1606200)National Science Foundation of China(Nos.12090062,12105008)the Major State Basic Research Development Program of China.
文摘We present the preparation and measurement of the radioactive isotope^(37)Ar,which was produced using thermal neutrons from a reactor,as a calibration source for liquid xenon time projection chambers.^(37)Ar is a low-energy calibration source with a half-life of 35.01 days,making it suitable for calibration in the low-energy region of liquid xenon dark-matter experiments.Radioactive isotope^(37)Ar was produced by irradiating ^(36)Ar with thermal neutrons.It was subsequently measured in a gaseous xenon time projection chamber(GXe TPC)to validate its radioactivity.Our results demonstrate that^(37)Ar is an effective and viable calibration source that offers precise calibration capabilities in the low-energy domain of xenon-based detectors.
基金supported by the National Natural Science Foundation of China(42430303)Strategy Priority Research Program(Category B)of the Chinese Academy of Sciences(XDB0710000)+2 种基金National Natural Science Foundation of China(42288201)the National Key R&D Program of China(2023YFF0803203)the IGGCAS start-up funding(Grant No.E251510101).
文摘In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly(effectively imposing a wavelet-spectrum weighting,often akin to an amplitude-squared bias).This redundancy degrades structural fidelity and amplitude balance yet is frequently overlooked.We(i)formalize the mechanism by which cross-correlation duplicates the source-wavelet amplitude effect in both migration and demigration,and(ii)introduce a source-equalized operator that removes the redundancy by deconvolving(or dividing by)the wavelet amplitude spectrum in the imaging condition and its demigration counterpart,while leaving phase/kinematics intact.Using a band-limited Ricker wavelet on a two-layer model and on Marmousi,we show that,if unmanaged,the redundant wavelet spectrum broadens main lobes,introduces ringing,and suppresses vertical resolution in migrated images,and inflates spectrum mismatches between demigrated and observed data even when peak times agree.With our correction,images recover observed-data-consistent bandwidth and sharpened interfaces,and demigrated data also exhibit improved spectrum conformity and reduced amplitude misfit.The results clarify when source amplitudes matter,why cross-correlation makes them redundantly matter,and how a lightweight spectral correction restores physically meaningful amplitude behavior in wave-equation migration/demigration.
基金support from the Natural Science Foundation of Jiangsu Province(Grant No.BK20240036)the National Natural Science Foundation of China(Grant Nos.U24A20515,22276099,and 22361162668)Guangxi Key Research and Development Program,China(Grant No.Guike AB24010074)。
文摘We conducted a field campaign to investigate the chemical composition,sources,and light absorption of submicron aerosols(PM_(1))from early 2022 in Nanjing,China.The average concentration of PM_(1) was 31μg m^(−3),organics(33%)constituted the largest fraction,followed by nitrate(30%),sulfate(18%),ammonium(15%),chloride(3%),and rBC(2%).Four organic aerosol(OA)subcomponents were identified,including two primary OA(POA)and two secondary OA(SOA).The less-oxidized SOA(LO-OOA)contributes the most to the total OA mass(59%).LO-OOA is tightly correlated with the tracer ion C_(2)H_(4)O_(2)^(+)from levoglucosan,and another aged biomass-burning derived species,K_(3)SO_(4)^(+),suggesting it was likely influenced by aged biomass-burning OA.Our study also revealed that fireworks during the Spring Festival have a detrimental impact on air quality,contributing to secondary formation and accumulation under static winter meteorological conditions,prolonging the pollution duration.Also,LO-OOA was found to have the strongest light-absorbing ability.Our results highlight that the light absorption of LO-OOA can mainly be attributed to the C_(x)H_(y)N^(+) family,increased with the double-bond equivalent value.The more-oxidized SOA(MO-OOA)exhibited a negligible light absorption and was strongly correlated with daytime photochemical processes,implying a light-bleaching effect.This study enhances our understanding of the regional contribution of biomass combustion and fireworks to PM_(1) pollution in Nanjing,a typical megacity in the Yangtze River Delta region,during winter,aiding in the development of strategies for long-term air quality improvement in the region.
