To overcome the limitations of traditional experimental“trial and error”methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular me...To overcome the limitations of traditional experimental“trial and error”methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular mechanism of the antioxidant reaction of hindered phenol,diphenylamine,and alkyl sulfide are studied via molecular simulations.Calculation results show that the strong electron-donating ability and high hydrogen-donating activity of the antioxidant molecule and the low hydrogen-abstracting activity of free radicals formed after dehydrogenation are the internal molecular causes of the shielding of phenol and diphenylamine from scavenging peroxy free radicals,and the strong electron-donating ability is the internal molecular cause of the high activity of thioether in decomposing alkyl hydrogen peroxide.Based on this antioxidant molecular mechanism,a molecular design rule of antioxidant is proposed,namely“high EHOMO,large Q(S),low bond dissociation energy BDE(O—H)and BDE(N—H)”.Two new antioxidants,PAS-I and PAS-II,are designed and prepared by chemical bonding of hindered phenol,diphenylamine,and sulfur atoms.Experimental results show that these antioxidants both have excellent antioxidant effects in lubricating oil,and that PAS-II is the superior antioxidant,consistent with theoretical predictions.展开更多
IgA肾病(immunoglobulin A nephropathy,IgAN)属于常见的原发性肾小球肾炎之一,也是终末期肾病(end-stage renal disease,ESRD)的主要病因之一。IgAN的治疗仍然存在挑战,干预相关的危险因素,可延缓疾病的进展。近年发现,高尿酸血症是IgA...IgA肾病(immunoglobulin A nephropathy,IgAN)属于常见的原发性肾小球肾炎之一,也是终末期肾病(end-stage renal disease,ESRD)的主要病因之一。IgAN的治疗仍然存在挑战,干预相关的危险因素,可延缓疾病的进展。近年发现,高尿酸血症是IgAN患者常见的临床特点,也是疾病进展的危险因素之一,但高尿酸血症与IgAN病理改变及疾病进展的关系仍不明确。因此,明确高尿酸血症与IgAN的关系具有重要的临床意义。本文从高尿酸血症在IgAN中的患病率、相关的发病机制与IgAN进展的关系及治疗靶点等方面进行了较为详尽的综述。展开更多
Based on existing triaxial compression experimental data,a new empirical failure criterion with wide applicability was proposed considering hydrostatic pressure,second stress invariance,and maximum shear stress.Four f...Based on existing triaxial compression experimental data,a new empirical failure criterion with wide applicability was proposed considering hydrostatic pressure,second stress invariance,and maximum shear stress.Four fitting evaluation indicators were used to verify the consistency of the new failure criterion,and the differences with the other 6 failure criteria were discussed.The characteristics of the new failure criteria in the principal stress space were finally analyzed.The results indicate that(1)the new failure criterion exhibits strong predictive ability for triaxial experiments and has good applicability for both intact and jointed rocks;(2)the influence of hydrostatic pressure on the failure surface exhibits a non-linear trend,and different hydrostatic pressure also exhibits different distribution patterns on the deviatoric stress plane,with a distribution characteristic pattern of hexagonal snowflake-regular hexagon.The maximum shear stress has a torsional effect on the new criterion,in the three-dimensional failure surface.The parameters a and b of the rock have an impact on the failure surface morphology of the new criterion function on the offset surface.展开更多
文摘To overcome the limitations of traditional experimental“trial and error”methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular mechanism of the antioxidant reaction of hindered phenol,diphenylamine,and alkyl sulfide are studied via molecular simulations.Calculation results show that the strong electron-donating ability and high hydrogen-donating activity of the antioxidant molecule and the low hydrogen-abstracting activity of free radicals formed after dehydrogenation are the internal molecular causes of the shielding of phenol and diphenylamine from scavenging peroxy free radicals,and the strong electron-donating ability is the internal molecular cause of the high activity of thioether in decomposing alkyl hydrogen peroxide.Based on this antioxidant molecular mechanism,a molecular design rule of antioxidant is proposed,namely“high EHOMO,large Q(S),low bond dissociation energy BDE(O—H)and BDE(N—H)”.Two new antioxidants,PAS-I and PAS-II,are designed and prepared by chemical bonding of hindered phenol,diphenylamine,and sulfur atoms.Experimental results show that these antioxidants both have excellent antioxidant effects in lubricating oil,and that PAS-II is the superior antioxidant,consistent with theoretical predictions.
文摘IgA肾病(immunoglobulin A nephropathy,IgAN)属于常见的原发性肾小球肾炎之一,也是终末期肾病(end-stage renal disease,ESRD)的主要病因之一。IgAN的治疗仍然存在挑战,干预相关的危险因素,可延缓疾病的进展。近年发现,高尿酸血症是IgAN患者常见的临床特点,也是疾病进展的危险因素之一,但高尿酸血症与IgAN病理改变及疾病进展的关系仍不明确。因此,明确高尿酸血症与IgAN的关系具有重要的临床意义。本文从高尿酸血症在IgAN中的患病率、相关的发病机制与IgAN进展的关系及治疗靶点等方面进行了较为详尽的综述。
基金supported by the National Natural Science Foundation of China(Nos.52004289 and U22A20165)the Fundamental Research Funds for the Central Universities(No.2022XJNY01)。
文摘Based on existing triaxial compression experimental data,a new empirical failure criterion with wide applicability was proposed considering hydrostatic pressure,second stress invariance,and maximum shear stress.Four fitting evaluation indicators were used to verify the consistency of the new failure criterion,and the differences with the other 6 failure criteria were discussed.The characteristics of the new failure criteria in the principal stress space were finally analyzed.The results indicate that(1)the new failure criterion exhibits strong predictive ability for triaxial experiments and has good applicability for both intact and jointed rocks;(2)the influence of hydrostatic pressure on the failure surface exhibits a non-linear trend,and different hydrostatic pressure also exhibits different distribution patterns on the deviatoric stress plane,with a distribution characteristic pattern of hexagonal snowflake-regular hexagon.The maximum shear stress has a torsional effect on the new criterion,in the three-dimensional failure surface.The parameters a and b of the rock have an impact on the failure surface morphology of the new criterion function on the offset surface.
