Exploring impedance spectrum for lithium-ion batteries diagnosis and prognosis:A comprehensive review

Lithium-ion batteries have extensive usage in various energy storage needs,owing to their notable benefits of high energy density and long lifespan.The monitoring of battery states and failure identification are indispensable for guaranteeing the secure and optimal functionality of the batteries.The impedance spectrum has garnered growing interest due to its ability to provide a valuable understanding of material characteristics and electrochemical processes.To inspire further progress in the investigation and application of the battery impedance spectrum,this paper provides a comprehensive review of the determination and utilization of the impedance spectrum.The sources of impedance inaccuracies are systematically analyzed in terms of frequency response characteristics.The applicability of utilizing diverse impedance features for the diagnosis and prognosis of batteries is further elaborated.Finally,challenges and prospects for future research are discussed.

Understanding the Novel Approach of Nanoferroptosis for Cancer Therapy

As a new form of regulated cell death,ferroptosis has unraveled the unsolicited theory of intrinsic apoptosis resistance by cancer cells.The molecular mechanism of ferroptosis depends on the induction of oxidative stress through excessive reactive oxygen species accumulation and glutathione depletion to damage the structural integrity of cells.Due to their high loading and structural tunability,nanocarriers can escort the delivery of ferro-therapeutics to the desired site through enhanced permeation or retention effect or by active targeting.This review shed light on the necessity of iron in cancer cell growth and the fascinating features of ferroptosis in regulating the cell cycle and metastasis.Additionally,we discussed the effect of ferroptosis-mediated therapy using nanoplatforms and their chemical basis in overcoming the barriers to cancer therapy.

One-step preparation of efficient cuprous chloride catalyst for direct synthesis of trimethoxysilane

CuCl-based catalysts are the most commonly used catalysts for the“direct synthesis”of trimethoxysilane(M3).CuCl species are sensitive to air and water,and are prone to oxidation deactivation.When CuCl is directly used as a catalyst,it needs to be purified before the utilization,and the operating conditions for the catalyst preparation are relatively harsh,requiring the inert gas environment.Considering a high-temperature activation step required for CuCl-based catalysts used for catalyzing synthesis of M3 to form active phase Cu–Si alloys(Cu_(x)Si)with Si powder,in this work,a series of catalysts for the“direct synthesis”of M3 were obtained by a one-step high-temperature activation of the mixture of stable CuCl_(2) precursors,activated carbon-reducing agent,and Si powder,simultaneously achieving the reduction of CuCl_(2) to CuCl and the formation of active phase Cu_(x)Si alloys of CuCl with Si powder.The prepared samples were characterized through various characterization techniques,and investigated for the catalytic performance for the“direct synthesis”of M3.Moreover,the operation conditions were optimized,including the activation temperature,catalyst dosage,Si powder particle size,and reaction temperature.The characterization results indicate that during the one-step activation process,the CuCl_(2) precursor is reduced to CuCl,and the resulting CuCl simultaneously reacts with Si powder to form active phases Cu3Si and Cu15Si4 alloys.The optimal catalyst Sacm(250,0.8:10)exhibits a good catalytic activity with selectivity of 95%and yield of 77%for M3,and shows a good universality for various alcohol substrates.Furthermore,the catalytic mechanism of the prepared catalyst for the“direct synthesis”of M3 was discussed.

Mass transfer enhancement and hydrodynamic performance with wire mesh coupling solid particles in bubble column reactor

It is of vital significance to investigate mass transfer enhancements for chemical engineering processes.This work focuses on investigating the coupling influence of embedding wire mesh and adding solid particles on bubble motion and gas-liquid mass transfer process in a bubble column.Particle image velocimetry(PIV)technology was employed to analyze the flow field and bubble motion behavior,and dynamic oxygen absorption technology was used to measure the gas-liquid volumetric mass transfer coefficient(kLa).The effect of embedding wire mesh,adding solid particles,and wire mesh coupling solid particles on the flow characteristic and kLa were analyzed and compared.The results show that the gas-liquid interface area increases by 33%-72%when using the wire mesh coupling solid particles strategy compared to the gas-liquid two-phase flow,which is superior to the other two strengthening methods.Compared with the system without reinforcement,kLa in the bubble column increased by 0.5-1.8 times with wire mesh coupling solid particles method,which is higher than the sum of kLa increases with inserting wire mesh and adding particles,and the coupling reinforcement mechanism for affecting gas-liquid mass transfer process was discussed to provide a new idea for enhancing gas-liquid mass transfer.

Rosemary extract improves egg quality by altering gut barrier function,intestinal microbiota and oviductal gene expressions in late-phase laying hens

Background Rosemary extract(RE)has been reported to exert antioxidant property.However,the application of RE in late-phase laying hens on egg quality,intestinal barrier and microbiota,and oviductal function has not been systematically studied.This study was investigated to detect the potential effects of RE on performance,egg quality,serum parameters,intestinal heath,cecal microbiota and metabolism,and oviductal gene expressions in late-phase laying hens.A total of 21065-week-old“Jing Tint 6”laying hens were randomly allocated into five treatments with six replicates and seven birds per replicate and fed basal diet(CON)or basal diet supplemented with chlortetracycline at 50 mg/kg(CTC)or RE at 50 mg/kg(RE50),100 mg/kg(RE100),and 200 mg/kg(RE200).Results Our results showed that RE200 improved(P<0.05)Haugh unit and n-6/n-3 of egg yolk,serum superoxide dismutase(SOD)compared with CON.No significant differences were observed for Haugh unit and n-6/n-3 of egg yolk among CTC,RE50,RE100 and RE200 groups.Compared with CTC and RE50 groups,RE200 increased serum SOD activity on d 28 and 56.Compared with CON,RE supplementation decreased(P<0.05)total cholesterol(TC)level.CTC,RE100 and RE200 decreased(P<0.05)serum interleukin-6(IL-6)content compared with CON.CTC and RE200 increased jejunal m RNA expression of ZO-1 and Occludin compared with CON.The biomarkers of cecal microbiota and metabolite induced by RE 200,including Firmicutes,Eisenbergiella,Paraprevotella,Papillibacter,and butyrate,were closely associated with Haugh unit,n-6/n-3,SOD,IL-6,and TC.PICRUSt2 analysis indicated that RE altered carbohydrate and amino acid metabolism of cecal microbiota and increased butyrate synthesizing enzymes,including 3-oxoacid Co A-transferase and butyrate-acetoacetate Co A-transferase.Moreover,transcriptomic analysis revealed that RE200 improved gene expressions and functional pathways related to immunity and albumen formation in the oviductal magnum.Conclusions Dietary supplementation with 200 mg/kg RE could increase egg quality of late-phase laying hens via modulating intestinal barrier,cecal microbiota and metabolism,and oviductal function.Overall,RE could be used as a promising feed additive to improve egg quality of laying hens at late stage of production.

Power transfer efficiency in an air-breathing radio frequency ion thruster

Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.

Quantitative method to predict the energetics of helium-nanocavities interactions in metal systems based on electrophobic interaction

Energetics of helium-nanocavities interactions are crucial for unveiling underlying mechanisms of nanocavity evolution in nuclear materials.Nevertheless,it becomes intractable and even not feasible to obtain these energetics via atomic simulations with increasing nanocavity size and increasing helium content in nanocavities.Herein,a universal scaling law of helium-induced interaction energies in nanocavities in metal systems is proposed based on electrophobic interaction of helium.Based on this scaling law and ab-initio calculations,a predictive method for binding energies of helium and displacement defects to nanocavities of arbitrary sizes and with different helium/vacancy ratios is established for BCC iron as a representative and validated by atomic simulations.This predictive method reveals that the critical helium/vacancy ratio for helium-enhanced vacancy binding to nanocavities in-creases with increasing nanocavity size,and the helium/vacancy ratio giving the highest stability of nanocavities is about 1.6.The Ostwald ripening of nanocavities is delayed by helium to higher temper-atures due to reduced vacancy de-trapping rates from nanocavities.The proposed scaling law can be generalized to many metal systems studied in the nuclear materials community.Being readily coupled into mesoscale models of irradiation damages,this predictive method facilitates clarifying helium role in cavity swelling of metallic nuclear materials.

Experimental studies of H_(2)/Ar plasma in a cylindrical inductive discharge with an expansion region

The electrical parameters of H_(2)/Ar plasma in a cylindrical inductive discharge with an expansion region are investigated by a Langmuir probe,where Ar fractions range from 0%to 100%.The influence of gas composition and pressure on electron density,the effective electron temperature and the electron energy probability functions(EEPFs)at different spatial positions are present.In driver region,with the introduction of a small amount of Ar at 0.3 Pa,there is a rapid increase in electron density accompanied by a decrease in the effective electron temperature.Additionally,the shape of the EEPF transitions from a three-temperature distribution to a bi-Maxwellian distribution due to an increase in electron-electron collision.However,this phenomenon resulting from the changes in gas composition vanishes at 5 Pa due to the prior depletion of energetic electrons caused by the increase in pressure during hydrogen discharge.The EEPFs for the total energy in expansion region is coincident to these in the driver region at 0.3 Pa,as do the patterns of electron density variation between these two regions for differing Ar fractions.At 5 Pa,as the discharge transitions from H_(2)to Ar,the EEPFs evolved from a bi-Maxwellian distribution with pronounced low energy electrons to a Maxwellian distribution in expansion region.This evolve may be attributed to a reduction in molecular vibrational excitation reactions of electrons during transport and the transition from localized electron dynamics in hydrogen discharge to non-localized electron dynamics in argon discharge.In order to validate the experimental results,we use the COMSOL simulation software to calculate electrical parameters under the same conditions.The evolution and spatial distribution of the electrical parameters of the simulation results agree well with the trend of the experimental results.

遗传修饰猪模型在生物医学及农业领域研究进展及应用

猪在解剖结构、代谢、生理生化等特征方面比啮齿类动物更接近人类,因此在模拟某些人类疾病以及提供异种移植器官等方面具有其他动物不可替代的优势,是理想的人类疾病动物模型和异种器官的供体。另外,猪作为我国畜牧业最重要的物种之一,猪的品种改良、疫病防控以及动物福利等问题都与人民生活息息相关。本文主要介绍了遗传修饰猪模型在分子育种、人类疾病模型以及异种器官移植领域的研究进展及未来应用前景,希望增进相关领域研究人员对基因编辑等前沿技术的了解,理解遗传修饰猪模型在生命科学研究中的重要意义。

The MING proposal at SHINE:megahertz cavity enhanced X‑ray generation

The cavity-based X-ray free-electron laser(XFEL)has promise in producing fully coherent pulses with a bandwidth of a few meV and very stable intensity,whereas the currently existing self-amplified spontaneous emission(SASE)XFEL is capable of generating ultra-short pulses with chaotic spectra.In general,a cavity-based XFEL can provide a spectral brightness three orders of magnitude higher than that of the SASE mode,thereby opening a new door for cutting-edge scientific research.With the development of superconducting MHz repetition-rate XFEL facilities such as FLASH,European-XFEL,LCLS-II,and SHINE,practical cavity-based XFEL operations are becoming increasingly achievable.In this study,megahertz cavity enhanced X-ray generation(MING)is proposed based on China’s first hard XFEL facility-SHINE,which we refer to as MING@SHINE.

Eukaryotic food sources analysis in situ of tropical common sea cucumber Holothuria leucospilota based on 18S rRNA gene high-throughput sequencing

Sea cucumber Holothuria leucospilota is one of the most widespread tropical holothurian species.In this study,eukaryotic organism composition in foregut and hindgut contents of H.leucospilota and surrounding sediments was assessed by 18S rRNA gene high-throughput sequencing.Eukaryon richness and diversity in the habitat sediments were significantly higher than those in foregut and hindgut contents of the sea cucumbers(P<0.05).The foregut content group,hindgut content group,and marine sediment group sequences were respectively assigned to 18.20±1.32,19.40±1.03,and 21.80±0.37 phyla.In the foregut contents,Nematoda(20.18%±9.59%),Mollusca(16.12%±10.49%),Chlorophyta(10.04%±4.85%),Annelida(8.72%±10.93%),Streptophyta(8.46%±4.65%),and Diatomea(5.99%±2.01%)were the predominant phyla,which showed the eukaryotic food sources of H.leucospilota were primarily belong to the above phyla.The predominant phyla in the hindgut contents were Streptophyta(45.55%±17.32%),Mollusca(4.93%±4.82%),Arthropoda(5.37%±3.08%),Diatomea(3.88%±2.34%),and Chlorophyta(3.79%±1.59%);and Annelida(37.80%±17.00%),Arthropoda(24.49%±12.53%),Platyhelminthes(7.14%±3.02%),Nematoda(4.14%±0.91%),and Diatomea(5.11%±1.35%)had large contents in the sediments.The comparatively high content of Paris genus in phylum Streptophyta in foregut contents indicated that land plants were one of the primary food sources of H.leucospilota,however the significantly higher contents of Streptophyta in hindgut contents than that in foregut contents might suggest a large part of the terrigenous detritus ingested might not be digested by H.leucospilota.UPGMA and PCoA analysis revealed that eukaryotic organism composition differed significantly between foregut contents of H.leucospilota and ambient sediments,indicating selective feeding feature of H.leucospilota.This study provided useful references for artificial feed of tropical sea cucumbers and enhanced understanding of the ecological roles of detritus-feeding macrobenthos.

Molecular dynamics study of interactions between edge dislocation and irradiation-induced defects in Fe–10Ni–20Cr alloy

Irradiation-induced defects frequently impede the slip of dislocations, resulting in a sharp decline in the performance of nuclear reactor structural materials, particularly core structural materials. In the present work, molecular dynamics method is used to investigate the interactions between edge dislocations and three typical irradiation-induced defects(void,Frank loop, and stacking fault tetrahedron) with the sizes of 3 nm, 5 nm, and 7 nm at different temperatures in Fe–10Ni–20Cr alloy. The critical resolved shear stresses(CRSSs) are compared among different defect types after interacting with edge dislocations. The results show that the CRSS decreases with temperature increasing and defect size decreasing for each defect type during the interaction with edge dislocations, except for the case of 3-nm Frank loops at 900 K. According to a comparison, the CRSS in Frank loop is significantly higher than that of others of the same size, which is due to the occurrence of unfaulting and formation of superjog or stacking-fault complex during the interaction. The atomic evolution of irradiation-induced defects after interacting with dislocations can provide a novel insight into the design of new structural materials.

Acoustic propagation uncertainty in internal wave environments using an ocean-acoustic joint model

An ocean-acoustic joint model is developed for research of acoustic propagation uncertainty in internal wave environments.The internal waves are numerically produced by tidal forcing over a continental slope using an ocean model.Three parameters(i.e.,internal wave,source depth,and water depth)contribute to the dynamic waveguide environments,and result in stochastic sound fields.The sensitivity of the transmission loss(TL)to environment parameters,statistical characteristics of the TL variation,and the associated physical mechanisms are investigated by the Sobol sensitivity analysis method,the Monte Carlo sampling,and the coupled normal mode theory,respectively.The results show that the TL is most sensitive to the source depth in the near field,resulted from the initial amplitudes of higher-order modes;while in middle and far fields,the internal waves are responsible for more than 80%of the total acoustic propagation contribution.In addition,the standard deviation of the TL in the near field and the shallow layer is smaller than those in the middle and far fields and the deep layer.

Concomitant occurrences of pulmonary embolism and acute myocardial infarction in acute coronary syndrome patient undergoing percutaneous coronary intervention:a case report

Pulmonary embolism(PE),a form of venous thromboembolism,is a relatively frequent car-diovascular emergency,and a potentially life-threatening condition that needs prompt identification and treatment.[1]PE is often misdiagnosed or unrecogn-ized with many patients experiencing atypical sympt-oms.[2,3]Early diagnosis and treatment of PE are import-ant.In this case,PE was found in a 73-year-old male pa-tient with three-vessel coronary artery disease who un-derwent percutaneous coronary intervention(PCI)for concomitant acute myocardial infarction(MI).

Coordinated transcriptional and post-transcriptional epigenetic regulation during skeletal muscle development and growth in pigs

Background:N6-methyladenosine(m^(6)A)and DNA 5-methylcytosine(5mC)methylation plays crucial roles in diverse biological processes,including skeletal muscle development and growth.Recent studies unveiled a potential link between these two systems,implicating the potential mechanism of coordinated transcriptional and post-transcrip-tional regulation in porcine prenatal myogenesis and postnatal skeletal muscle growth.Methods:Immunofluorescence and co-IP assays were carried out between the 5mC writers and m^(6)A writers to investigate the molecular basis underneath.Large-scale in-house transcriptomic data were compiled for applying weighted correlation network analysis(WGCNA)to identify the co-expression patterns of m^(6)A and 5mC regulators and their potential role in pig myogenesis.Whole-genome bisulfite sequencing(WGBS)and methylated RNA immu-noprecipitation sequencing(MeRIP-seq)were performed on the skeletal muscle samples from Landrace pigs at four postnatal growth stages(days 30,60,120 and 180).Results:Significantly correlated expression between 5mC writers and m^(6)A writers and co-occurrence of 5mC and m^(6)A modification were revealed from public datasets of C2C12 myoblasts.The protein-protein interactions between the DNA methylase and the m^(6)A methylase were observed in mouse myoblast cells.Further,by analyzing tran-scriptome data comprising 81 pig skeletal muscle samples across 27 developmental stages,we identified a 5mC/m^(6)A epigenetic module eigengene and decoded its potential functions in pre-or post-transcriptional regulation in postnatal skeletal muscle development and growth of pigs.Following integrative multi-omics analyses on the WGBS methylome data and MeRIP-seq data for both m^(6)A and gene expression profiles revealed a genome/transcriptome-wide correlated dynamics and co-occurrence of 5mC and m^(6)A modifications as a consequence of 5mC/m^(6)A crosstalk in the postnatal myogenesis progress of pigs.Last,we identified a group of myogenesis-related genes collaboratively regulated by both 5mC and m^(6)A modifications in postnatal skeletal muscle growth in pigs.Conclusions:Our study discloses a potential epigenetic mechanism in skeletal muscle development and provides a novel direction for animal breeding and drug development of related human muscle-related diseases.

Whole‑genome transcriptome and DNA methylation dynamics of pre‑implantation embryos reveal progression of embryonic genome activation in buffaloes

Background During mammalian pre-implantation embryonic development(PED),the process of maternal-to-zygote transition(MZT)is well orchestrated by epigenetic modification and gene sequential expression,and it is related to the embryonic genome activation(EGA).During MZT,the embryos are sensitive to the environment and easy to arrest at this stage in vitro.However,the timing and regulation mechanism of EGA in buffaloes remain obscure.Results Buffalo pre-implantation embryos were subjected to trace cell based RNA-seq and whole-genome bisulfite sequencing(WGBS)to draw landscapes of transcription and DNA-methylation.Four typical developmental steps were classified during buffalo PED.Buffalo major EGA was identified at the 16-cell stage by the comprehensive analy-sis of gene expression and DNA methylation dynamics.By weighted gene co-expression network analysis,stage-spe-cific modules were identified during buffalo maternal-to-zygotic transition,and key signaling pathways and biological process events were further revealed.Programmed and continuous activation of these pathways was necessary for success of buffalo EGA.In addition,the hub gene,CDK1,was identified to play a critical role in buffalo EGA.Conclusions Our study provides a landscape of transcription and DNA methylation in buffalo PED and reveals deeply the molecular mechanism of the buffalo EGA and genetic programming during buffalo MZT.It will lay a foundation for improving the in vitro development of buffalo embryos.

Mitigating thermal runaway hazard of high-energy lithium-ion batteries by poison agent

Lithium-ion batteries with high-energy density are extensively commercialized in long-range electric vehicles. However, they are poor in thermal stability and pose fire or explosion, which has attracted the global attention. This study describes a new route to mitigate the battery thermal runaway(TR) hazard by poison agents. First, the self-destructive cell is built using the embedded poison layer. Then, the poisoning mechanism and paths are experimentally investigated at the material, electrode, and cell levels. Finally, the proposed route is verified by TR tests. The results show the TR hazard can be significantly reduced in the self-destructive cell based on a new reaction sequence regulation. Specifically, the maximum temperature of the self-destructive cell is more than 300℃ lower than that of the normal cell during TR. The drop in maximum temperature can reduce total heat release and the probability of TR propagation in the battery system, significantly improving battery safety.

Linked color imaging vs Lugol chromoendoscopy for esophageal squamous cell cancer and precancerous lesion screening: A noninferiority study

BACKGROUND Lugol chromoendoscopy(LCE)has served as a standard screening technique in high-risk patients with esophageal cancer.Nevertheless,LCE is not suitable for general population screening given its side effects.Linked color imaging(LCI)is a novel image-enhanced endoscopic technique that can distinguish subtle differences in mucosal color.AIM To compare the diagnostic performance of LCI with LCE in detecting esophageal squamous cell cancer and precancerous lesions and to evaluate whether LCE can be replaced by LCI in detecting esophageal neoplastic lesions.METHODS In this prospective study,we enrolled 543 patients who underwent white light imaging(WLI),LCI and LCE successively.We compared the sensitivity and specificity of LCI and LCE in the detection of esophageal neoplastic lesions.Clinicopathological features and color analysis of lesions were assessed.RESULTS In total,43 patients(45 neoplastic lesions)were analyzed.Among them,36 patients(38 neoplastic lesions)were diagnosed with LCI,and 39 patients(41 neoplastic lesions)were diagnosed with LCE.The sensitivity of LCI was similar to that of LCE(83.7%vs 90.7%,P=0.520),whereas the specificity of LCI was greater than that of LCE(92.4%vs 87.0%,P=0.007).The LCI procedure time in the esophageal examination was significantly shorter than that of LCE[42(34,50)s vs 160(130,189)s,P<0.001].The color difference between the lesion and surrounding mucosa in LCI was significantly greater than that observed with WLI.However,the color difference in LCI was similar in different pathological types of esophageal squamous cell cancer.CONCLUSION LCI offers greater specificity than LCE in the detection of esophageal squamous cell cancer and precancerous lesions,and LCI represents a promising screening strategy for general populations.

3D fluid model analysis on the generation of negative hydrogen ions for negative ion source of NBI

A radio-frequency(RF) inductively coupled negative hydrogen ion source(NHIS) has been adopted in the China Fusion Engineering Test Reactor(CFETR) to generate negative hydrogen ions.By incorporating the level-lumping method into a three-dimensional fluid model,the volume production and transportation of H^(-) in the NHIS,which consists of a cylindrical driver region and a rectangular expansion chamber,are investigated self-consistently at a large input power(40 k W) and different pressures(0.3–2.0 Pa).The results indicate that with the increase of pressure,the H^(-) density at the bottom of the expansion region first increases and then decreases.In addition,the effect of the magnetic filter is examined.It is noteworthy that a significant increase in the H^(-) density is observed when the magnetic filter is introduced.As the permanent magnets move towards the driver region,the H^(-) density decreases monotonically and the asymmetry is enhanced.This study contributes to the understanding of H-distribution under various conditions and facilitates the optimization of volume production of negative hydrogen ions in the NHIS.

A fast hybrid simulation approach of ion energy and angular distributions in biased inductively coupled Ar plasmas

In this work,a two-dimensional hybrid model,which consists of a bulk fluid module,a sheath module and an ion Monte-Carlo module,is developed to investigate the modulation of ion energy and angular distributions at different radial positions in a biased argon inductively coupled plasma.The results indicate that when the bias voltage amplitude increases or the bias frequency decreases,the ion energy peak separation width becomes wider.Besides,the widths of the ion energy peaks at the edge of the substrate are smaller than those at the center due to the lower plasma density there,indicating the nonuniformity of the ion energy distribution function(IEDF)along the radial direction.As the pressure increases from 1 to 10 Pa,the discrepancy of the IEDFs at different radial positions becomes more obvious,i.e.the IEDF at the radial edge is characterized by multiple low energy peaks.When a dual frequency bias source is applied,the IEDF exhibits three or four peaks,and it could be modulated efficiently by the relative phase between the two bias frequencies.The results obtained in this work could help to improve the radial uniformity of the IEDF and thus the etching process.