In this study,the benign target double terpyridine parts based amphiphilic ionic molecules(AIMs 1,2)and the reference single terpyridine segment included AIMs(AIMs 3,4)were synthesized through a multi-step method,and ...In this study,the benign target double terpyridine parts based amphiphilic ionic molecules(AIMs 1,2)and the reference single terpyridine segment included AIMs(AIMs 3,4)were synthesized through a multi-step method,and the molecular structures were fully characterized.The excellent anticorrosion of the target AIMs for copper surface in H_(2)SO_(4) solution was demonstrated by the electrochemistry analysis,which was more superior over those of the reference AIMs.The standard adsorption free energy changes of the target AIMs calculated by the adsorption isotherms were lower than -40 kJ·mol^(-1),suggesting an intensified chemical adsorption on metal surface.The molecular modeling and molecular dynamic computation of the studied AIMs were performed,demonstrating that the target AIMs exhibited lower highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps and greater adsorption energies than the reference ones.The chemical adsorption of the AIMs on metal surface was revealed by various spectroscopic methods including scanning electron microscopy,atomic force microscopy,Fourier transform infrared spectroscopy,attenuated total reflection infrared spectroscopy,Raman and X-ray diffraction.展开更多
In this study, an approach was proposed to employ new target branched compounds(TBCs) including multiple antibiotic norfloxacin frameworks for intensified adsorption films to achieve super protection of mild steel in ...In this study, an approach was proposed to employ new target branched compounds(TBCs) including multiple antibiotic norfloxacin frameworks for intensified adsorption films to achieve super protection of mild steel in HCl medium. Thus, the TBCs containing bis/tri norfloxacin skeletons were synthesized by multi-step preparation route. In addition, the reference linear compound(RLC) including a single norfloxacin part was also synthesized. The chemical structures of these compounds were confirmed by various means. It was demonstrated that the TBCs could form the tough adsorption films on the surface of mild steel, which could be processed mainly through chemisorption effect. The electrochemical analysis suggested that the TBCs displayed superior corrosion inhibition performance for low carbon steel in1.0 mol·L^(-1) HCl solution over the RLC(RLC, 87.80%;TBC1, 97.63%;TBC2, 98.35%), which was further understood by the molecular modelling. The isotherm adsorption plots were employed to analyze the spontaneous adsorption process of the TBCs on low carbon steel surface, and a prominent chemisorption could be inferred by the standard Gibbs free energy changes of the adsorption.展开更多
The Chang’E-6 mission will first land on the far side of the moon and bring lunar samples back.As a hyperspectral imager aboard the Chang’E-6 lander,the Lunar Mineralogical Spectrometer(LMS),will achieve the goal of...The Chang’E-6 mission will first land on the far side of the moon and bring lunar samples back.As a hyperspectral imager aboard the Chang’E-6 lander,the Lunar Mineralogical Spectrometer(LMS),will achieve the goal of spectral detection and mineral composition analysis in the sampling area,and the data of LMS will also be compared with the results of the returned sample laboratory measurements.Visible and near-infrared hyperspectral remote sensing is an effective tool for lunar minerals identification and quantification.The ground validation experiment can be used to evaluate the detection ability of the LMS.According to the modal abundances of lunar minerals and glasses of APOLLO samples,binary mixed samples,ternary mixed samples,and seven-membered mixed samples were prepared.The samples were ground and stirred homogeneous to about 200 mesh(median particle size about 75μm),to simulate the soil state of the lunar surface.Under the laboratory ambient condition,the 480–3200 nm spectral data of the samples were acquired using the Engineering Qualification Model(EQM)of Chang’E-5 LMS,the performance of which is consistent with the flight model of Chang’E-6 LMS.By fitting the mixed samples’spectral data of the EQM using the Modified Gaussian Methods,the following conclusions can be drawn:The subtle spectral changes of mixed samples can be detected.The modal abundance of low-Ca pyroxene,high-Ca pyroxene,and plagioclase can be derived based on the spectral parameters such as absorption position,depth or width of the mixed samples,and the correlation coefficients R2are better than 82%,indicating that the LMS has good quantitative detection capability.展开更多
Agronomically optimizing the timing and rates of nitrogen(N) fertilizer application can increase crop yield and decrease N loss to the environment. Wheat(Triticum aestivum L.)–peanut(Arachis hypogaea L.) relay interc...Agronomically optimizing the timing and rates of nitrogen(N) fertilizer application can increase crop yield and decrease N loss to the environment. Wheat(Triticum aestivum L.)–peanut(Arachis hypogaea L.) relay intercropping systems are a mainstay of economic and food security in China. We performed a field experiment to investigate the effects of N fertilizer on N recovery efficiency, crop yield, and N loss rate in wheat–peanut relay intercropping systems in the Huang-Huai-Hai Plain, China during 2015–2017. The N was applied on the day before sowing, the jointing stage(G30) or the booting stage(G40) of winter wheat, and the anthesis stage(R1) of peanut in the following percentage splits: 50-50-0-0(N1), 35-35-0-30(N2), and 35-0-35-30(N3), using 300 kg N ha-1, with 0 kg N ha-1(N0) as control. ^(15)N-labeled(20.14 atom %) urea was used to trace the fate of N in microplots. The yields of wheat and peanut increased by 12.4% and 15.4% under the N2 and N3 treatments, relative to those under the N1 treatment. The ^(15)N recovery efficiencies( ^(15)NRE) were 64.9% and 58.1% for treatments N2 and N3, significantly greater than that for the N1 treatment(45.3%). The potential N loss rates for the treatments N2 and N3 were23.7% and 7.0%, significantly lower than that for treatment N1(30.1%). Withholding N supply until the booting stage(N3) did not reduce the wheat grain yield; however, it increased the N content derived from ^(15)N-labeled urea in peanuts, promoted the distribution of ^(15)N to pods, and ultimately increased pod yields in comparison with those obtained by topdressing N at jointing stage(N2). In comparison with N2, the N uptake and N recovery efficiency(NRE) of N3 was increased by 12.0% and 24.1%,respectively, while the apparent N loss decreased by 16.7%. In conclusion, applying N fertilizer with three splits and delaying topdressing fertilization until G40 of winter wheat increased total grain yields and NRE and reduced N loss. This practice could be an environment-friendly N management strategy for wheat–peanut relay intercropping systems in China.展开更多
The induction and proliferation of embryogenic callus are key steps for large-scale propagation of somatic embryogenesis pathway and long-term preservation of coniferous germplasm.Callus can be induced from immature e...The induction and proliferation of embryogenic callus are key steps for large-scale propagation of somatic embryogenesis pathway and long-term preservation of coniferous germplasm.Callus can be induced from immature embryos of Korean pine(Pinus koraiensis Sieb.et Zucc.;Pinaceae)as explants,but there are problems,such as low proliferation efficiency,loss of embryogenicity,poor vigor;thus,best conditions for proliferation and culture of immature embryos of Korean pine are not yet clear.To solve the problems with somatic embryogenesis of Korean pine and determine the best culture conditions for callus induction and proliferation,we varied hormone concentration,subculture cycle of proliferation and other plant growth regulators combinations in media to induce callus formation by megagametophytes of three Korean pine families at different developmental stages,then analyzed the effects on embryogenic callus retention and cell proliferation using a quadratic regression orthogonal rotation design.The results showed that the family origin and collection date of explants significantly affected callus induction(induction rate reached 1.67%).Embryogenic maintenance and callus proliferation were best on DCR medium supplemented with 0.25 mg L^(−1)6-benzyl adenine,1 mg L^(−1)naphthaleneacetic acid,30 g L^(−1)sucrose,500 mg L^(−1),L-glutamine,500 mg L^(−1)casein hydrolysis and 6.5 g L^(−1)agar.In addition,the combination of 2,4-dichlorophenoxyacetic acid+6-benzyl adenine also had a better proliferative effect on callus.The effects of different combinations of growth regulators on callus proliferation efficiency were significantly different.Transfer to new medium every 13–15 days not only maintained robust callus vigor,but also yielded a larger proliferation coefficient.The techniques and conditions for embryogenic callus induction and proliferation of Korean determined here will serve as a foundation for establishing a large-scale system for somatic embryogenesis and propagation of Korean pine.展开更多
Gastric cancer(GC) is the third leading cause of cancerrelated death worldwide.In areas of high prevalence,such as Japan,South Korea and China,most cases of GC are related to Helicobacter pylori(H.pylori),which involv...Gastric cancer(GC) is the third leading cause of cancerrelated death worldwide.In areas of high prevalence,such as Japan,South Korea and China,most cases of GC are related to Helicobacter pylori(H.pylori),which involves well-characterized sequential stages,including infection,atrophic gastritis,intestinal metaplasia,dysplasia,and GC.Mucins are the most abundant highmolecular-weight glycoproteins in mucus,which is the first line of defense and plays a major role in blocking pathogenic factors.Normal gastric mucosa shows expression of MUC1,MUC5 AC and MUC6 that is specific to cell type.However,the specific pattern of MUC1,MUC5 AC and MUC6 expression is changed in gastric carcinogenesis,accompanied by de novo expression of secreted MUC2.Recent studies have provided evidence that variations in these mucin genes affect many steps of GC development,such as H.pylori infection,and gastric precancerous lesions.In this review,we focus on studies of the association between polymorphisms in mucin genes and development of GC.This information should be helpful for the early detection,surveillance,and treatment of GC.展开更多
Continuum robot is a new type of biomimetic robot,which realizes the motion by bending some parts of its body.So its path planning becomes more difficult even compared with hyper-redundant robots.In this paper a circu...Continuum robot is a new type of biomimetic robot,which realizes the motion by bending some parts of its body.So its path planning becomes more difficult even compared with hyper-redundant robots.In this paper a circular arc spline interpolating method is proposed for the robot shape description,and a new two-stage position-selectable-updating particle swarm optimization(TPPSO)algorithm is put forward to solve this path planning problem.The algorithm decomposes the standard PSO velocity’s single-step updating formula into twostage multi-point updating,specifically adopting three points as candidates and selecting the best one as the updated position in the first half stage,and similarly taking seven points as candidates and selecting the best one as the final position in the last half stage.This scheme refines and widens each particle’s searching trajectory,increases the updating speed of the individual best,and improves the converging speed and precision.Aiming at the optimization objective to minimize the sum of all the motion displacements of every segmental points and all the axial stretching or contracting displacements of every segment,the TPPSO algorithm is used to solve the path planning problem.The detailed solution procedure is presented.Numerical examples of five path planning cases show that the proposed algorithm is simple,robust,and efficient.展开更多
The spectophotometry of charge transfer (CT) complexes of tetrachloro-p-benzoquinone(TCB) with tertiary amine [triethylamine (TEA), triphylamine (TPA), N,N-dimethylphenylamine(DMPA), N-ethylcarbazole (ECZ)] have been ...The spectophotometry of charge transfer (CT) complexes of tetrachloro-p-benzoquinone(TCB) with tertiary amine [triethylamine (TEA), triphylamine (TPA), N,N-dimethylphenylamine(DMPA), N-ethylcarbazole (ECZ)] have been studied in dichloromethane in UV-visible region.The CT complexes parameter, molar ratio of reactAnts in complex, molar extinction coefficient equilibrium constant KCT, free energy G and dissociation energy of the CT complex excited stateE, have also been estimated and discussed.展开更多
This letter presents excited state intramolecular proton transfer (ESIPT) of new conjugated derivatives containing hydroxy and imino groups. ESIPT occurrence in one photon process is confirmed by well-separated emissi...This letter presents excited state intramolecular proton transfer (ESIPT) of new conjugated derivatives containing hydroxy and imino groups. ESIPT occurrence in one photon process is confirmed by well-separated emission band for the derivatives. Two- photon absorption (TPA) induced ESIPT emission has been determined by Ti:sapphire femtosecond laser tuning from 700 nrn to 800 nm at the internals of 20 nm.展开更多
To understand the effect of injected deuterium(D)pellets on background plasma,the ablation of D pellets and the transport of D species in both atomic and ionic states in the EAST device are simulated using a modified ...To understand the effect of injected deuterium(D)pellets on background plasma,the ablation of D pellets and the transport of D species in both atomic and ionic states in the EAST device are simulated using a modified dynamic neutral gas shield model combined with the edge plasma code SOLPS-ITER.The simulation results show that there is a phenomenon of obvious atomic deposition in the scrape-off layer(SOL)after pellet injection,which depends strongly on the injection velocity.With increasing injection velocity,the atomic density in the SOL decreases evidently and the deposition time is relatively shortened.Possible effects for triggering of edge localized modes(ELMs)by D and Li pellets are also discussed.With the same pellet size and injection velocity,the maximum perturbation pressure caused by D pellets is obviously higher.It is found that the resulting maximum perturbed pressure is remarkably enhanced when the injection velocity is reduced from 300 m/s to 100 m/s for a pellet with a cross section of 1.6 mm,which indicates that the injection velocity is important for ELM pacing.This work can provide reasonable guidance for choosing pellet parameters for fueling and ELM triggering.展开更多
基金the National Natural Science Foundation of China (21376282,21676035,21878029)Chongqing Science and Technology Commission (cstc2018jcyjAX0668)+2 种基金Shandong Province Natural Science Foundation (ZR2020QB18)China Postdoctoral Science Foundation (22012 T50762&2011 M501388)Graduate Student Research Innovation Project,Chongqing University (CYB18046)。
文摘In this study,the benign target double terpyridine parts based amphiphilic ionic molecules(AIMs 1,2)and the reference single terpyridine segment included AIMs(AIMs 3,4)were synthesized through a multi-step method,and the molecular structures were fully characterized.The excellent anticorrosion of the target AIMs for copper surface in H_(2)SO_(4) solution was demonstrated by the electrochemistry analysis,which was more superior over those of the reference AIMs.The standard adsorption free energy changes of the target AIMs calculated by the adsorption isotherms were lower than -40 kJ·mol^(-1),suggesting an intensified chemical adsorption on metal surface.The molecular modeling and molecular dynamic computation of the studied AIMs were performed,demonstrating that the target AIMs exhibited lower highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps and greater adsorption energies than the reference ones.The chemical adsorption of the AIMs on metal surface was revealed by various spectroscopic methods including scanning electron microscopy,atomic force microscopy,Fourier transform infrared spectroscopy,attenuated total reflection infrared spectroscopy,Raman and X-ray diffraction.
基金the National Natural Science Foundation of China (21376282, 21676035, 21878029)Chongqing Science and Technology Commission (2022NSCQ-MSX1298)+1 种基金China Postdoctoral Science Foundation (22012T50762 & 2011M501388)Graduate Student Research Innovation Project, Chongqing University (CYB18046)。
文摘In this study, an approach was proposed to employ new target branched compounds(TBCs) including multiple antibiotic norfloxacin frameworks for intensified adsorption films to achieve super protection of mild steel in HCl medium. Thus, the TBCs containing bis/tri norfloxacin skeletons were synthesized by multi-step preparation route. In addition, the reference linear compound(RLC) including a single norfloxacin part was also synthesized. The chemical structures of these compounds were confirmed by various means. It was demonstrated that the TBCs could form the tough adsorption films on the surface of mild steel, which could be processed mainly through chemisorption effect. The electrochemical analysis suggested that the TBCs displayed superior corrosion inhibition performance for low carbon steel in1.0 mol·L^(-1) HCl solution over the RLC(RLC, 87.80%;TBC1, 97.63%;TBC2, 98.35%), which was further understood by the molecular modelling. The isotherm adsorption plots were employed to analyze the spontaneous adsorption process of the TBCs on low carbon steel surface, and a prominent chemisorption could be inferred by the standard Gibbs free energy changes of the adsorption.
文摘The Chang’E-6 mission will first land on the far side of the moon and bring lunar samples back.As a hyperspectral imager aboard the Chang’E-6 lander,the Lunar Mineralogical Spectrometer(LMS),will achieve the goal of spectral detection and mineral composition analysis in the sampling area,and the data of LMS will also be compared with the results of the returned sample laboratory measurements.Visible and near-infrared hyperspectral remote sensing is an effective tool for lunar minerals identification and quantification.The ground validation experiment can be used to evaluate the detection ability of the LMS.According to the modal abundances of lunar minerals and glasses of APOLLO samples,binary mixed samples,ternary mixed samples,and seven-membered mixed samples were prepared.The samples were ground and stirred homogeneous to about 200 mesh(median particle size about 75μm),to simulate the soil state of the lunar surface.Under the laboratory ambient condition,the 480–3200 nm spectral data of the samples were acquired using the Engineering Qualification Model(EQM)of Chang’E-5 LMS,the performance of which is consistent with the flight model of Chang’E-6 LMS.By fitting the mixed samples’spectral data of the EQM using the Modified Gaussian Methods,the following conclusions can be drawn:The subtle spectral changes of mixed samples can be detected.The modal abundance of low-Ca pyroxene,high-Ca pyroxene,and plagioclase can be derived based on the spectral parameters such as absorption position,depth or width of the mixed samples,and the correlation coefficients R2are better than 82%,indicating that the LMS has good quantitative detection capability.
基金supported by the National Key Technology R&D Program of China (2014BAD11B04-2)the National Natural Science Foundation of China (30840056, 31171496)Shandong Modern Agricultural Technology and Industry System (SDAIT-04-01)
文摘Agronomically optimizing the timing and rates of nitrogen(N) fertilizer application can increase crop yield and decrease N loss to the environment. Wheat(Triticum aestivum L.)–peanut(Arachis hypogaea L.) relay intercropping systems are a mainstay of economic and food security in China. We performed a field experiment to investigate the effects of N fertilizer on N recovery efficiency, crop yield, and N loss rate in wheat–peanut relay intercropping systems in the Huang-Huai-Hai Plain, China during 2015–2017. The N was applied on the day before sowing, the jointing stage(G30) or the booting stage(G40) of winter wheat, and the anthesis stage(R1) of peanut in the following percentage splits: 50-50-0-0(N1), 35-35-0-30(N2), and 35-0-35-30(N3), using 300 kg N ha-1, with 0 kg N ha-1(N0) as control. ^(15)N-labeled(20.14 atom %) urea was used to trace the fate of N in microplots. The yields of wheat and peanut increased by 12.4% and 15.4% under the N2 and N3 treatments, relative to those under the N1 treatment. The ^(15)N recovery efficiencies( ^(15)NRE) were 64.9% and 58.1% for treatments N2 and N3, significantly greater than that for the N1 treatment(45.3%). The potential N loss rates for the treatments N2 and N3 were23.7% and 7.0%, significantly lower than that for treatment N1(30.1%). Withholding N supply until the booting stage(N3) did not reduce the wheat grain yield; however, it increased the N content derived from ^(15)N-labeled urea in peanuts, promoted the distribution of ^(15)N to pods, and ultimately increased pod yields in comparison with those obtained by topdressing N at jointing stage(N2). In comparison with N2, the N uptake and N recovery efficiency(NRE) of N3 was increased by 12.0% and 24.1%,respectively, while the apparent N loss decreased by 16.7%. In conclusion, applying N fertilizer with three splits and delaying topdressing fertilization until G40 of winter wheat increased total grain yields and NRE and reduced N loss. This practice could be an environment-friendly N management strategy for wheat–peanut relay intercropping systems in China.
基金supported by the National Key R&D Program of China(2017YFD0600600).
文摘The induction and proliferation of embryogenic callus are key steps for large-scale propagation of somatic embryogenesis pathway and long-term preservation of coniferous germplasm.Callus can be induced from immature embryos of Korean pine(Pinus koraiensis Sieb.et Zucc.;Pinaceae)as explants,but there are problems,such as low proliferation efficiency,loss of embryogenicity,poor vigor;thus,best conditions for proliferation and culture of immature embryos of Korean pine are not yet clear.To solve the problems with somatic embryogenesis of Korean pine and determine the best culture conditions for callus induction and proliferation,we varied hormone concentration,subculture cycle of proliferation and other plant growth regulators combinations in media to induce callus formation by megagametophytes of three Korean pine families at different developmental stages,then analyzed the effects on embryogenic callus retention and cell proliferation using a quadratic regression orthogonal rotation design.The results showed that the family origin and collection date of explants significantly affected callus induction(induction rate reached 1.67%).Embryogenic maintenance and callus proliferation were best on DCR medium supplemented with 0.25 mg L^(−1)6-benzyl adenine,1 mg L^(−1)naphthaleneacetic acid,30 g L^(−1)sucrose,500 mg L^(−1),L-glutamine,500 mg L^(−1)casein hydrolysis and 6.5 g L^(−1)agar.In addition,the combination of 2,4-dichlorophenoxyacetic acid+6-benzyl adenine also had a better proliferative effect on callus.The effects of different combinations of growth regulators on callus proliferation efficiency were significantly different.Transfer to new medium every 13–15 days not only maintained robust callus vigor,but also yielded a larger proliferation coefficient.The techniques and conditions for embryogenic callus induction and proliferation of Korean determined here will serve as a foundation for establishing a large-scale system for somatic embryogenesis and propagation of Korean pine.
基金Supported by National Natural Science Foundation of China,No.30960169 and No.81250024Natural Science Foundation of Inner Mongolia,No.2011MS1103Inner Mongolian Committee of Science and Technology,China,No.20110501
文摘Gastric cancer(GC) is the third leading cause of cancerrelated death worldwide.In areas of high prevalence,such as Japan,South Korea and China,most cases of GC are related to Helicobacter pylori(H.pylori),which involves well-characterized sequential stages,including infection,atrophic gastritis,intestinal metaplasia,dysplasia,and GC.Mucins are the most abundant highmolecular-weight glycoproteins in mucus,which is the first line of defense and plays a major role in blocking pathogenic factors.Normal gastric mucosa shows expression of MUC1,MUC5 AC and MUC6 that is specific to cell type.However,the specific pattern of MUC1,MUC5 AC and MUC6 expression is changed in gastric carcinogenesis,accompanied by de novo expression of secreted MUC2.Recent studies have provided evidence that variations in these mucin genes affect many steps of GC development,such as H.pylori infection,and gastric precancerous lesions.In this review,we focus on studies of the association between polymorphisms in mucin genes and development of GC.This information should be helpful for the early detection,surveillance,and treatment of GC.
基金Supported by the Fundamental Research Funds for the Central Universities(Grant No.DL09CB02)the Heilongjiang Province Natural Science Fund(Grant No.E201013)
文摘Continuum robot is a new type of biomimetic robot,which realizes the motion by bending some parts of its body.So its path planning becomes more difficult even compared with hyper-redundant robots.In this paper a circular arc spline interpolating method is proposed for the robot shape description,and a new two-stage position-selectable-updating particle swarm optimization(TPPSO)algorithm is put forward to solve this path planning problem.The algorithm decomposes the standard PSO velocity’s single-step updating formula into twostage multi-point updating,specifically adopting three points as candidates and selecting the best one as the updated position in the first half stage,and similarly taking seven points as candidates and selecting the best one as the final position in the last half stage.This scheme refines and widens each particle’s searching trajectory,increases the updating speed of the individual best,and improves the converging speed and precision.Aiming at the optimization objective to minimize the sum of all the motion displacements of every segmental points and all the axial stretching or contracting displacements of every segment,the TPPSO algorithm is used to solve the path planning problem.The detailed solution procedure is presented.Numerical examples of five path planning cases show that the proposed algorithm is simple,robust,and efficient.
文摘The spectophotometry of charge transfer (CT) complexes of tetrachloro-p-benzoquinone(TCB) with tertiary amine [triethylamine (TEA), triphylamine (TPA), N,N-dimethylphenylamine(DMPA), N-ethylcarbazole (ECZ)] have been studied in dichloromethane in UV-visible region.The CT complexes parameter, molar ratio of reactAnts in complex, molar extinction coefficient equilibrium constant KCT, free energy G and dissociation energy of the CT complex excited stateE, have also been estimated and discussed.
基金financial support from National Natural Science Foundation of China(Nos.20776165, 20702065,20872184)We would thank"the Foundation of Chongqing Science and Technology Commission"(Nos. CSTC2008BA4020,CSTC2009BB4216)
文摘This letter presents excited state intramolecular proton transfer (ESIPT) of new conjugated derivatives containing hydroxy and imino groups. ESIPT occurrence in one photon process is confirmed by well-separated emission band for the derivatives. Two- photon absorption (TPA) induced ESIPT emission has been determined by Ti:sapphire femtosecond laser tuning from 700 nrn to 800 nm at the internals of 20 nm.
基金the National Key R&D Program of China under Grant Nos.2017YFE0301100 and 2019YFE03030004the National Natural Science Foundation of China under Grant No.11575039Users with Excellence Program of Hefei Science Center CAS(2020HSCUE010)。
文摘To understand the effect of injected deuterium(D)pellets on background plasma,the ablation of D pellets and the transport of D species in both atomic and ionic states in the EAST device are simulated using a modified dynamic neutral gas shield model combined with the edge plasma code SOLPS-ITER.The simulation results show that there is a phenomenon of obvious atomic deposition in the scrape-off layer(SOL)after pellet injection,which depends strongly on the injection velocity.With increasing injection velocity,the atomic density in the SOL decreases evidently and the deposition time is relatively shortened.Possible effects for triggering of edge localized modes(ELMs)by D and Li pellets are also discussed.With the same pellet size and injection velocity,the maximum perturbation pressure caused by D pellets is obviously higher.It is found that the resulting maximum perturbed pressure is remarkably enhanced when the injection velocity is reduced from 300 m/s to 100 m/s for a pellet with a cross section of 1.6 mm,which indicates that the injection velocity is important for ELM pacing.This work can provide reasonable guidance for choosing pellet parameters for fueling and ELM triggering.