It is important to understand the effects of demineralization on the reactivity of coal pyrolysis for demineralization coal in OCCSS systems.The molecular dynamics of the pyrolysis of ZD-R and ZD-D was investigated us...It is important to understand the effects of demineralization on the reactivity of coal pyrolysis for demineralization coal in OCCSS systems.The molecular dynamics of the pyrolysis of ZD-R and ZD-D was investigated using the ReaxFF MD method.It is indicated that the pyrolysis reactivity of ZD-D is enhanced.Acid demineralization treatment helps to enhance the cross-linking reaction of light tar C5-14 molecules in the main pyrolysis stage,generating light tar fragments with higher molecular mass.In the polycondensation pyrolysis stage,the acid demineralization treatment promotes the polycondensation reaction at high temperatures.The generation of H2 in ZD-R pyrolysis is primarily attributed to the N-H bond breaking in pyrrole at low temperatures.At high temperatures,it is predominantly associated with the hydrogen abstraction reaction between carboxyl functional groups and the dehydrogenation reaction of hydrogen bond breaking in the aliphatic hydrocarbon structures.H2O is primarily attributed to the reaction of the hydroxyl group on the carboxyl group.CO_(2) is always related to the carboxyl group.CO is mainly related to the reduction reaction of carbonyl group,carboxyl group,and CO_(2).During the initial pyrolysis stage of ZD-D after acid demineralization treatment,the hydrogen abstraction reaction of the carboxyl functional group and the generation of CO molecules by the methoxy group are enhanced.The generation of H2 by the aliphatic structure is enhanced in the main pyrolysis stage.The ring-opening reaction of the phenoxy group to generate CO in the polycondensation pyrolysis stage is also facilitated.展开更多
S100 proteins govern cellular proliferation,differentiation,apoptosis,calcium homeostasis,energy metabolism,and inflammation.This heterodimeric calcium-binding protein,consisting of the S100A8 and S100A9 subunits,modu...S100 proteins govern cellular proliferation,differentiation,apoptosis,calcium homeostasis,energy metabolism,and inflammation.This heterodimeric calcium-binding protein,consisting of the S100A8 and S100A9 subunits,modulates myeloid cell development.展开更多
In-situ TEM observation was conducted during Ni^(+)&He^(+)dual-beam irradiation to monitor the evolution of dislocation loops accompanied by He bubbles in the Ni-based alloy GH3535.Two distinct evolutions of dislo...In-situ TEM observation was conducted during Ni^(+)&He^(+)dual-beam irradiation to monitor the evolution of dislocation loops accompanied by He bubbles in the Ni-based alloy GH3535.Two distinct evolutions of dislocation loops,driven by residual stresses,were observed within the monitored grains.Hence,molec-ular dynamics(MD)simulations were employed to reveal the effects of stress magnitude and direction on loop evolution,including size,number density,type and variation.The simulations revealed that the presence of compressive stress reduced the formation energy of perfect dislocation loops,thus promoting their formation.Stress state was found to influence the preferential orientation of the loops,and com-pressive stress resulted in a decreased number density of dislocation loops but an increase in their size.This establishes a clear relationship between stress state and magnitude and the evolution of dislocation loops during ion beam irradiation.Additionally,the nature and characteristics of dislocation loops were quantified to explore the effects of He concentrations on their evolution.The higher He concentration not only promotes the nucleation of dislocation loops,leading to their higher number density,but also facil-itates the unfaulting evolution by increasing the stacking fault energy(SFE).Moreover,the accumulation of He in the lower-He-concentration sample led to the growth of dislocation loops in multiple stages,explaining their nearly identical average sizes when compared to the higher-He-concentration sample.展开更多
The influence of nitrogen-containing polycyclic aromatic hydrocarbons(NC-PAH)on the formation of carbonaceous mesophase remains enigmatic,despite extensive research on the production of carbonaceous materials from aro...The influence of nitrogen-containing polycyclic aromatic hydrocarbons(NC-PAH)on the formation of carbonaceous mesophase remains enigmatic,despite extensive research on the production of carbonaceous materials from aromatic-rich oils.Molecular dynamics simulation was used to investigate the variations in pyrolysis behavior between PAH and NC-PAH based on the composition analysis.Through adjusting the content of NC-PAH,the influence of NC-PAH on the thermal stability of slurry oils(SOs)was evaluated by thermogravimetry,viscosity,coke value,and quinoline insoluble(QI).The morphology and structure of mesocarbon microbeads(MCMBs)prepared with SOs were measured by a polarized-light microscope,SEM,XRD,and Raman.Simulation results indicate that NC-PAH possesses much higher reactivity and tends to produce highly condensed solid and coke products.It corresponds to the QI and high viscosity in thermal stability experiments.Therefore,high concentrations of NC-PAH result in nonuniform morphology and disordered structures.In a system with low viscosity and few QIs,SO,which has a low nitrogen content(475 ppm),reacts gently to produce MCMBs with a uniform particle size(10-40μm)and an excellent spherical shape.As NC-PAH content decreases,the crystalline size of graphitization elevates,as evidenced by parallel layers(10.472-11.764)and stack height(3.269-3.701 nm).The graphitization degree becomes worse and nonuniform with the increase of the content of NC-PAH,and the best is 20.58%evaluated by Raman spectra area ratio(AG/Aall).Overall,this work suggests a nitrogen content reference and a controlling technology of nitrogen for the preparation of superior MCMB.展开更多
本研究采用文献计量学方法,总结当前土壤质量研究中最小数据集(MDS)选取的方法和指标,定量分析并指出土壤质量评价中最小数据集的热点和前沿,为中国土壤质量评价和农业绿色发展提供科学参考。通过检索1991-2022年CNKI和Web of Science...本研究采用文献计量学方法,总结当前土壤质量研究中最小数据集(MDS)选取的方法和指标,定量分析并指出土壤质量评价中最小数据集的热点和前沿,为中国土壤质量评价和农业绿色发展提供科学参考。通过检索1991-2022年CNKI和Web of Science相关文献,收集了文献中310个最小数据集进行筛选,借助CiteSpace和VOSviewer对年度发文量、国家/地区、机构、期刊进行共现分析,对关键词进行突现词和聚类分析。31年来该领域文献量逐步增加并仍处于快速发展阶段,中国是发文量最多的国家,期刊载文量最多的为《土壤通报》《生态学报》和Ecological Indicators;主要研究热点表现在“农业管理对土壤质量影响、土壤退化与修复、土壤质量对气候变化的响应与应对及最小数据集筛选方法与模型构建”等方面;前期MDS在土壤质量评价中选用较多的主要为物理、化学指标,但随着土壤健康的发展,生物学指标逐步增长。在未来一段时间内MDS发文量仍为快速增长阶段,发展中国家在全球起着重要节点作用;MDS核心指标为土壤有机质/碳(SOM/SOC)、pH、全氮、速效磷和容重;未来研究应注重在基于大数据平台构建不同尺度下静态评价与动态监测相结合的综合反映土壤功能的土壤健康质量评价框架体系,探讨气候变化背景下与土壤质量变化相对应的MDS及其指标体系,构建精准反映土壤质量变化规律的评价模型与最优最小数据集。展开更多
文摘It is important to understand the effects of demineralization on the reactivity of coal pyrolysis for demineralization coal in OCCSS systems.The molecular dynamics of the pyrolysis of ZD-R and ZD-D was investigated using the ReaxFF MD method.It is indicated that the pyrolysis reactivity of ZD-D is enhanced.Acid demineralization treatment helps to enhance the cross-linking reaction of light tar C5-14 molecules in the main pyrolysis stage,generating light tar fragments with higher molecular mass.In the polycondensation pyrolysis stage,the acid demineralization treatment promotes the polycondensation reaction at high temperatures.The generation of H2 in ZD-R pyrolysis is primarily attributed to the N-H bond breaking in pyrrole at low temperatures.At high temperatures,it is predominantly associated with the hydrogen abstraction reaction between carboxyl functional groups and the dehydrogenation reaction of hydrogen bond breaking in the aliphatic hydrocarbon structures.H2O is primarily attributed to the reaction of the hydroxyl group on the carboxyl group.CO_(2) is always related to the carboxyl group.CO is mainly related to the reduction reaction of carbonyl group,carboxyl group,and CO_(2).During the initial pyrolysis stage of ZD-D after acid demineralization treatment,the hydrogen abstraction reaction of the carboxyl functional group and the generation of CO molecules by the methoxy group are enhanced.The generation of H2 by the aliphatic structure is enhanced in the main pyrolysis stage.The ring-opening reaction of the phenoxy group to generate CO in the polycondensation pyrolysis stage is also facilitated.
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.82170160 and 32000604)the Provincial Natural Science Foundation of Hunan(Grant Nos.2021JJ30163 and 2022JJ20021)+3 种基金the Changsha Municipal Natural Science Foundation(Grant No.kq2007053)the Global Research Award from American Society of Hematology to Y.Mpartially supported by the National Natural Science Foundation of China(Grant No.82470145)Mount Taishan Scholar Young Expert of Shandong Province(Grant No.tsqn202103167)to S.X。
文摘S100 proteins govern cellular proliferation,differentiation,apoptosis,calcium homeostasis,energy metabolism,and inflammation.This heterodimeric calcium-binding protein,consisting of the S100A8 and S100A9 subunits,modulates myeloid cell development.
基金supported by the National Natural Science Foundation of China(Nos.U2341261 and 12375280)the Young Potential Program of Shanghai Institute of Applied Physics,Chinese Academy of Sciences(No.YXJH-2022002)the National MCF Energy R&D Program(No.2022YFE03110000).
文摘In-situ TEM observation was conducted during Ni^(+)&He^(+)dual-beam irradiation to monitor the evolution of dislocation loops accompanied by He bubbles in the Ni-based alloy GH3535.Two distinct evolutions of dislocation loops,driven by residual stresses,were observed within the monitored grains.Hence,molec-ular dynamics(MD)simulations were employed to reveal the effects of stress magnitude and direction on loop evolution,including size,number density,type and variation.The simulations revealed that the presence of compressive stress reduced the formation energy of perfect dislocation loops,thus promoting their formation.Stress state was found to influence the preferential orientation of the loops,and com-pressive stress resulted in a decreased number density of dislocation loops but an increase in their size.This establishes a clear relationship between stress state and magnitude and the evolution of dislocation loops during ion beam irradiation.Additionally,the nature and characteristics of dislocation loops were quantified to explore the effects of He concentrations on their evolution.The higher He concentration not only promotes the nucleation of dislocation loops,leading to their higher number density,but also facil-itates the unfaulting evolution by increasing the stacking fault energy(SFE).Moreover,the accumulation of He in the lower-He-concentration sample led to the growth of dislocation loops in multiple stages,explaining their nearly identical average sizes when compared to the higher-He-concentration sample.
基金support of National Natural Science Foundation of P.R.China(22308104).
文摘The influence of nitrogen-containing polycyclic aromatic hydrocarbons(NC-PAH)on the formation of carbonaceous mesophase remains enigmatic,despite extensive research on the production of carbonaceous materials from aromatic-rich oils.Molecular dynamics simulation was used to investigate the variations in pyrolysis behavior between PAH and NC-PAH based on the composition analysis.Through adjusting the content of NC-PAH,the influence of NC-PAH on the thermal stability of slurry oils(SOs)was evaluated by thermogravimetry,viscosity,coke value,and quinoline insoluble(QI).The morphology and structure of mesocarbon microbeads(MCMBs)prepared with SOs were measured by a polarized-light microscope,SEM,XRD,and Raman.Simulation results indicate that NC-PAH possesses much higher reactivity and tends to produce highly condensed solid and coke products.It corresponds to the QI and high viscosity in thermal stability experiments.Therefore,high concentrations of NC-PAH result in nonuniform morphology and disordered structures.In a system with low viscosity and few QIs,SO,which has a low nitrogen content(475 ppm),reacts gently to produce MCMBs with a uniform particle size(10-40μm)and an excellent spherical shape.As NC-PAH content decreases,the crystalline size of graphitization elevates,as evidenced by parallel layers(10.472-11.764)and stack height(3.269-3.701 nm).The graphitization degree becomes worse and nonuniform with the increase of the content of NC-PAH,and the best is 20.58%evaluated by Raman spectra area ratio(AG/Aall).Overall,this work suggests a nitrogen content reference and a controlling technology of nitrogen for the preparation of superior MCMB.
文摘本研究采用文献计量学方法,总结当前土壤质量研究中最小数据集(MDS)选取的方法和指标,定量分析并指出土壤质量评价中最小数据集的热点和前沿,为中国土壤质量评价和农业绿色发展提供科学参考。通过检索1991-2022年CNKI和Web of Science相关文献,收集了文献中310个最小数据集进行筛选,借助CiteSpace和VOSviewer对年度发文量、国家/地区、机构、期刊进行共现分析,对关键词进行突现词和聚类分析。31年来该领域文献量逐步增加并仍处于快速发展阶段,中国是发文量最多的国家,期刊载文量最多的为《土壤通报》《生态学报》和Ecological Indicators;主要研究热点表现在“农业管理对土壤质量影响、土壤退化与修复、土壤质量对气候变化的响应与应对及最小数据集筛选方法与模型构建”等方面;前期MDS在土壤质量评价中选用较多的主要为物理、化学指标,但随着土壤健康的发展,生物学指标逐步增长。在未来一段时间内MDS发文量仍为快速增长阶段,发展中国家在全球起着重要节点作用;MDS核心指标为土壤有机质/碳(SOM/SOC)、pH、全氮、速效磷和容重;未来研究应注重在基于大数据平台构建不同尺度下静态评价与动态监测相结合的综合反映土壤功能的土壤健康质量评价框架体系,探讨气候变化背景下与土壤质量变化相对应的MDS及其指标体系,构建精准反映土壤质量变化规律的评价模型与最优最小数据集。
