Induction heat treatment(IHT)is inherently an efficient,clean,economical and easy-operated rapid thermal oxide technology,which is well appliedto surface modification of titanium and its alloys in medical field in the...Induction heat treatment(IHT)is inherently an efficient,clean,economical and easy-operated rapid thermal oxide technology,which is well appliedto surface modification of titanium and its alloys in medical field in the research.This method produces titanium dioxide coatings with a micro-and nano-展开更多
Exploitable or potentially exploitable deposits of critical metals,such as rare-earth(REE)and high-field-strength elements(HFSE),are commonly associated with alkaline or peralkaline igneous rocks.However,the origin,tr...Exploitable or potentially exploitable deposits of critical metals,such as rare-earth(REE)and high-field-strength elements(HFSE),are commonly associated with alkaline or peralkaline igneous rocks.However,the origin,transport and concentration of these metals in peralkaline systems remains poorly understood.This study presents the results of a mineralogical and geochemical investigation of the Na-metasomatism of alkali amphiboles and clinopyroxenes from a barren peralkaline granite pluton in NE China,to assess the remobilization and redistribution of REE and HFSE during magmatic-hydrothermal evolution.Alkali amphiboles and aegirine-augites from the peralkaline granites show evolutionary trends from sodic-calcic to sodic compositions,with increasing REE and HFSE concentrations as a function of increasing Na-index[Na^(#),defined as molar Na/(Na+Ca)ratios].The Na-amphiboles(i.e.,arfvedsonite)and aegirine-augites can be subsequently altered,or breakdown,to form hydrothermal aegirine during late-or post-magmatic alteration.Representative compositions analyzed by insitu LA-ICPMS show that the primary aegirine-augites have high and variable REE(2194-3627 ppm)and HFSE(4194-16,862 ppm)contents,suggesting that these critical metals can be scavenged by alkali amphiboles and aegirine-augites.Compared to the primary aegirine-augites,the presentative early replacement aegirine(Aeg-I,Na^(#)=0.91-0.94)has notably lower REE(1484-1972)and HFSE(4351-5621)contents.In contrast,the late hydrothermal aegirine(Aeg-II,Na^(#)=0.92-0.96)has significantly lower REE(317-456 ppm)and HFSE(6.44-72.2 ppm)contents.Given that the increasing Na^(#)from aegirine-augites to hydrothermal aegirines likely resulted from Na-metasomatism,a scavenging-release model can explain the remobilization of REE and HFSE in peralkaline granitic systems.The scavenging and release of REE and HFSE by Na-metasomatism provides key insights into the genesis of globally significant REE and HFSE deposits.The high Na-index of the hydrothermal aegirine might be useful as a geochemical indicator in the exploration for these critical-metals.展开更多
In the presence of a catalytic amount of cesium hydroxide, the corresponding S-aryl phosphorothioates can he obtained by the reactions of dialkyl phosphites with diaryldisulfides in excellent yields at room temperatur...In the presence of a catalytic amount of cesium hydroxide, the corresponding S-aryl phosphorothioates can he obtained by the reactions of dialkyl phosphites with diaryldisulfides in excellent yields at room temperature, using DMSO as a solvent. The reaction mechanism was discussed. The method provides a new and expedient path for the preparation of $-aryl phosphorothioates.展开更多
文摘Induction heat treatment(IHT)is inherently an efficient,clean,economical and easy-operated rapid thermal oxide technology,which is well appliedto surface modification of titanium and its alloys in medical field in the research.This method produces titanium dioxide coatings with a micro-and nano-
基金financially supported by the National Natural Science Foundation of China(42122023 and 41930424)Key Research Program of the Innovation Academy for Earth Science,CAS(IGGCAS201901)+1 种基金Youth Innovation Promotion Association CAS(Y2021095)the Science and Technology Planning Project of Guangdong Province,China(2020B1212060055).
文摘Exploitable or potentially exploitable deposits of critical metals,such as rare-earth(REE)and high-field-strength elements(HFSE),are commonly associated with alkaline or peralkaline igneous rocks.However,the origin,transport and concentration of these metals in peralkaline systems remains poorly understood.This study presents the results of a mineralogical and geochemical investigation of the Na-metasomatism of alkali amphiboles and clinopyroxenes from a barren peralkaline granite pluton in NE China,to assess the remobilization and redistribution of REE and HFSE during magmatic-hydrothermal evolution.Alkali amphiboles and aegirine-augites from the peralkaline granites show evolutionary trends from sodic-calcic to sodic compositions,with increasing REE and HFSE concentrations as a function of increasing Na-index[Na^(#),defined as molar Na/(Na+Ca)ratios].The Na-amphiboles(i.e.,arfvedsonite)and aegirine-augites can be subsequently altered,or breakdown,to form hydrothermal aegirine during late-or post-magmatic alteration.Representative compositions analyzed by insitu LA-ICPMS show that the primary aegirine-augites have high and variable REE(2194-3627 ppm)and HFSE(4194-16,862 ppm)contents,suggesting that these critical metals can be scavenged by alkali amphiboles and aegirine-augites.Compared to the primary aegirine-augites,the presentative early replacement aegirine(Aeg-I,Na^(#)=0.91-0.94)has notably lower REE(1484-1972)and HFSE(4351-5621)contents.In contrast,the late hydrothermal aegirine(Aeg-II,Na^(#)=0.92-0.96)has significantly lower REE(317-456 ppm)and HFSE(6.44-72.2 ppm)contents.Given that the increasing Na^(#)from aegirine-augites to hydrothermal aegirines likely resulted from Na-metasomatism,a scavenging-release model can explain the remobilization of REE and HFSE in peralkaline granitic systems.The scavenging and release of REE and HFSE by Na-metasomatism provides key insights into the genesis of globally significant REE and HFSE deposits.The high Na-index of the hydrothermal aegirine might be useful as a geochemical indicator in the exploration for these critical-metals.
基金supported by the National Nature Science Foundation of China (Nos. 21273068, 21172061, J1210040)
文摘In the presence of a catalytic amount of cesium hydroxide, the corresponding S-aryl phosphorothioates can he obtained by the reactions of dialkyl phosphites with diaryldisulfides in excellent yields at room temperature, using DMSO as a solvent. The reaction mechanism was discussed. The method provides a new and expedient path for the preparation of $-aryl phosphorothioates.