Background： Corneal stromal cells （CSCs） are components of the corneal endothelial microenvironment that can be induced to form a functional tissue-engineered corneal endothelium. Adipose-derived mesenchymal stem c...Background： Corneal stromal cells （CSCs） are components of the corneal endothelial microenvironment that can be induced to form a functional tissue-engineered corneal endothelium. Adipose-derived mesenchymal stem cells （ADSCs） have been reported as an important component of regenerative medicine and cell therapy for corneal stromal damage. We have demonstrated that the treatment with ADSCs leads to phenotypic changes in CSCs in vitro. However, the underlying mechanisms of such ADSC-induced changes in CSCs remain unclear. Methods： ADSCs and CSCs were isolated from New Zealand white rabbits and cultured in vitro. An Exosome Isolation Kit, Western blotting, and nanoparticle tracking analysis （NTA） were used to isolate and confirm the exosomes from ADSC culture medium. Meanwhile, the optimal exosome concentration and treatment time were selected. Cell Counting Kit-8 and annexin V-fluorescein isothiocyanate/ propidium iodide assays were used to assess the effect of ADSC-derived exosomes on the proliferation and apoptosis of CSCs. To evaluate the effects ofADSC-derived exosomes on CSC invasion activity, Western blotting was used to detect the expression of matrix metalloproteinases （MMPs） and collagens. Results： ADSCs and CSCs were successfully isolated from New Zealand rabbits. The optimal concentration and treatment time of exosomes for the following study were 100 μg/ml and 96 h, respectively. NTA revealed that the ADSC-derived exosomes appeared as nanoparticles （40-200 nm）, and Western blotting confirmed positive expression of CD9, CDSI, flotillin-1, and HSP70 versus ADSC cytoplasmic proteins （all P〈 0.01 ）. ADSC-derived exosomes （50μg/ml and 100μg/ml） significantly promoted proliferation and inhibited apoptosis （mainly early apoptosis） of CSCs versus non-exosome-treated CSCs （all P 〈 0.05）. Interestingly, MMPs were downregulated and extracellular matrix （ECM）-related proteins including collagens and fibronectin were upregulated in the exosome-treated CSCs versus展开更多
The interfacial reactions of chalcopyrite in ammonia–ammonium chloride solution were investigated.The chalcopyrite surface was examined by scanning electron microscopy and X-ray photoelectron spectroscopy(XPS)techniq...The interfacial reactions of chalcopyrite in ammonia–ammonium chloride solution were investigated.The chalcopyrite surface was examined by scanning electron microscopy and X-ray photoelectron spectroscopy(XPS)techniques.It was found that interfacial passivation layers of chalcopyrite were formed from an iron oxide layer on top of a copper sulfide layer overlaying the bulk chalcopyrite,whereas CuFe1-xS2 or copper sulfides were formed via the preferential dissolution of Fe.The copper sulfide layer formed a new passivation layer,whereas the iron oxide layer peeled off spontaneously and partially from the chalcopyrite surface.The state of the copper sulfide layer was discussed after being deduced from the appearance of S2-,S22-,Sn2-,S0 and SO42-.A mechanism for the oxidation and passivation of chalcopyrite under different pH values and redox potentials was proposed.Accordingly,a model of the interfacial reaction on the chalcopyrite surface was constructed using a three-step reaction pathway,which demonstrated the formation and transformation of passivation layers under the present experimental conditions.展开更多
The effect of several parameters on the recovery of silicon dioxide from calcined boron mud（CBM）such as stirring speed, temperature, sodium silicate concentration, and carbonation time was studied. The recovery of s...The effect of several parameters on the recovery of silicon dioxide from calcined boron mud（CBM）such as stirring speed, temperature, sodium silicate concentration, and carbonation time was studied. The recovery of silicon dioxide is 88 % when the stirring speed is450 r min-1, temperature is 60 °C, sodium silicate concentration is 1 mol L-1, and the carbonation time is 6 h.The effect of carbonation time on the recovery of silicon dioxide is divided into three kinetic regimes, and the carbonation process of sodium silicate solution follows a second-order reaction based on the double-film theory model. The apparent rate constant of the three kinetic regimes is 0.064, 3.178, and 1.130 L h mol-1, respectively.The amorphous SiO_2 products obtained by carbonating the purified solution have 99.6 % purity and are spherical with diameters of about 100 nm.展开更多
Extreme ultraviolet lithography(EUVL)has been demonstrated to meet the industrial requirements of new-generation semiconductor fabrication.The development of high-power EUV sources is a long-term critical challenge to...Extreme ultraviolet lithography(EUVL)has been demonstrated to meet the industrial requirements of new-generation semiconductor fabrication.The development of high-power EUV sources is a long-term critical challenge to the implementation of EUVL in high-volume manufacturing(HVM),together with other technologies such as photoresist and mask.Historically,both theoretical studies and experiments have clearly indicated that the CO 2 laser-produced plasma(LPP)system is a promising solution for EUVL source,able to realize high conversion efficiency(CE)and output power.Currently,ASML’s NXE:3400B EUV scanner configuring CO_(2) LPP source sys-tem has been installed and operated at chipmaker customers.Mean-while,other research teams have made different progresses in the development of LPP EUV sources.However,in their technologies,some critical areas need to be further improved to meet the requirements of 5 nm node and below.Critically needed improvements include higher laser power,stable droplet generation system and longer collector life-time.In this paper,we describe the performance characteristics of the laser system,droplet generator and mirror collector for different EUV sources,and also the new development results.展开更多
Extracting B2O3 from calcined boron mud(CBM) was studied. The effect of factors such as reaction temperature and NaO H-to-CBM mass ratio on B2O3 extraction efficiency was investigated. The results show that increasing...Extracting B2O3 from calcined boron mud(CBM) was studied. The effect of factors such as reaction temperature and NaO H-to-CBM mass ratio on B2O3 extraction efficiency was investigated. The results show that increasing reaction temperature and NaO H-to-CBM mass ratio increases B2O3 extraction efficiency. There are two stages for the B2O3 extracting process: 0–20 min is the first stage, which is rapid; 20–50 min is the second stage, which is slower than the first stage. The overall extracting process follows the shrinking core model, and the first and second stages are determined to obey the surface chemical reaction model and the diffusion through the products layer model,respectively. The activation energies of the first and second stages are calculated to be 41.74 and 15.43 kJ·mol-1,respectively. The B2O3 extracting kinetics equations of the first and second stages are also obtained.展开更多
Nickel leaching from low-grade nickel matte(LGNM) using aqueous ferric chloride solution was studied.The influence of factors such as leaching temperature and concentration of ferric chloride on the nickel leaching ra...Nickel leaching from low-grade nickel matte(LGNM) using aqueous ferric chloride solution was studied.The influence of factors such as leaching temperature and concentration of ferric chloride on the nickel leaching ratio was investigated.The results show that increasing leaching temperature and concentration of ferric chloride increases the nickel leaching ratio.The overall nickel leaching process follows the unreacted shrinking core model,and the surface chemical reaction is the rate-controlling step.The activation energy and the reaction order of the nickel leaching process,controlled by the surface chemical reaction,were calculated to be 52.96 kJ mol^(-1)and 0.5,respectively.Therefore,the kinetics equation for the nickel leaching was found to be 1-(1-α)^(1/3)=7.18×10~4C^(0.5)exp[-52,960/(RT)]t.展开更多
NbC-Sn composite powder was successfully prepared from SnO2,Nb2O5and carbon by electrochemical reduction andcarbonization in CaCl2-NaCl molten salt at900°C.The reaction pathway was investigated by terminating ele...NbC-Sn composite powder was successfully prepared from SnO2,Nb2O5and carbon by electrochemical reduction andcarbonization in CaCl2-NaCl molten salt at900°C.The reaction pathway was investigated by terminating electrochemicalexperiments for various durations.The influence of carbon on the final products was considered.NbC particles were obtained byleaching the composite with acid.The results showed that the aggregated NbC-Sn composite powdev contained NbC particles about50-100nm and Sn particles about200nm.SnO2was reduced to Sn in the sintering process.Nb2O5was electrochemically reduced toNb in molten salt,experiencing some intermediate products of calcium niobates and niobium suboxides.Nb metal obtained wasconverted to NbC with assistance of carbon.The reduction of Nb oxides may be incomplete and Nb3Sn would be formed if carbon isinsufficient in the cathodic pellet.NbC with good dispersity is produced by leaching NbC-Sn with HCl.展开更多
The formation of a rust layer on iron and steels surfaces accelerates their degradation and eventually causes material failure.In addition to fabricating a protective layer or using a sacrificial anode, repairing or r...The formation of a rust layer on iron and steels surfaces accelerates their degradation and eventually causes material failure.In addition to fabricating a protective layer or using a sacrificial anode, repairing or removing the rust layer is another way to reduce the corrosion rate and extend the lifespans of iron and steels.Herein, an electrochemical healing approach was employed to repair the rust layer in molten Na_(2)CO_(3)-K_(2)CO_(3).The rusty layers on iron rods and screws were electrochemically converted to iron in only several minutes and a metallic luster appeared.Scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS) analyses showed that the structures of the rust layer after healing were slightly porous and the oxygen content reached a very low level.Thus, high-temperature molten-salt electrolysis may be an effective way to metalize iron rust of various shapes and structures in a short time, and could be used in the repair of cultural relics and even preparing a three-dimensional porous structures for other applications.展开更多
基金This work was supported by grants from the National Natural Science Foundation of China （No. 81700795）, and the Natural Science Foundation of Zhejiang Province （No. LY13H120007）.
文摘Background： Corneal stromal cells （CSCs） are components of the corneal endothelial microenvironment that can be induced to form a functional tissue-engineered corneal endothelium. Adipose-derived mesenchymal stem cells （ADSCs） have been reported as an important component of regenerative medicine and cell therapy for corneal stromal damage. We have demonstrated that the treatment with ADSCs leads to phenotypic changes in CSCs in vitro. However, the underlying mechanisms of such ADSC-induced changes in CSCs remain unclear. Methods： ADSCs and CSCs were isolated from New Zealand white rabbits and cultured in vitro. An Exosome Isolation Kit, Western blotting, and nanoparticle tracking analysis （NTA） were used to isolate and confirm the exosomes from ADSC culture medium. Meanwhile, the optimal exosome concentration and treatment time were selected. Cell Counting Kit-8 and annexin V-fluorescein isothiocyanate/ propidium iodide assays were used to assess the effect of ADSC-derived exosomes on the proliferation and apoptosis of CSCs. To evaluate the effects ofADSC-derived exosomes on CSC invasion activity, Western blotting was used to detect the expression of matrix metalloproteinases （MMPs） and collagens. Results： ADSCs and CSCs were successfully isolated from New Zealand rabbits. The optimal concentration and treatment time of exosomes for the following study were 100 μg/ml and 96 h, respectively. NTA revealed that the ADSC-derived exosomes appeared as nanoparticles （40-200 nm）, and Western blotting confirmed positive expression of CD9, CDSI, flotillin-1, and HSP70 versus ADSC cytoplasmic proteins （all P〈 0.01 ）. ADSC-derived exosomes （50μg/ml and 100μg/ml） significantly promoted proliferation and inhibited apoptosis （mainly early apoptosis） of CSCs versus non-exosome-treated CSCs （all P 〈 0.05）. Interestingly, MMPs were downregulated and extracellular matrix （ECM）-related proteins including collagens and fibronectin were upregulated in the exosome-treated CSCs versus
基金Project(2014CB643405)supported by the National Basic Research Program of China
文摘The interfacial reactions of chalcopyrite in ammonia–ammonium chloride solution were investigated.The chalcopyrite surface was examined by scanning electron microscopy and X-ray photoelectron spectroscopy(XPS)techniques.It was found that interfacial passivation layers of chalcopyrite were formed from an iron oxide layer on top of a copper sulfide layer overlaying the bulk chalcopyrite,whereas CuFe1-xS2 or copper sulfides were formed via the preferential dissolution of Fe.The copper sulfide layer formed a new passivation layer,whereas the iron oxide layer peeled off spontaneously and partially from the chalcopyrite surface.The state of the copper sulfide layer was discussed after being deduced from the appearance of S2-,S22-,Sn2-,S0 and SO42-.A mechanism for the oxidation and passivation of chalcopyrite under different pH values and redox potentials was proposed.Accordingly,a model of the interfacial reaction on the chalcopyrite surface was constructed using a three-step reaction pathway,which demonstrated the formation and transformation of passivation layers under the present experimental conditions.
基金financially supported by the National Natural Science Foundation of China(No.51204037)the Fundamental Research Funds for the Central UniversitiesChina(No.N140204016)
文摘The effect of several parameters on the recovery of silicon dioxide from calcined boron mud（CBM）such as stirring speed, temperature, sodium silicate concentration, and carbonation time was studied. The recovery of silicon dioxide is 88 % when the stirring speed is450 r min-1, temperature is 60 °C, sodium silicate concentration is 1 mol L-1, and the carbonation time is 6 h.The effect of carbonation time on the recovery of silicon dioxide is divided into three kinetic regimes, and the carbonation process of sodium silicate solution follows a second-order reaction based on the double-film theory model. The apparent rate constant of the three kinetic regimes is 0.064, 3.178, and 1.130 L h mol-1, respectively.The amorphous SiO_2 products obtained by carbonating the purified solution have 99.6 % purity and are spherical with diameters of about 100 nm.
基金supported by the National Key R&D Program of China(2019YFB1704600).
文摘Extreme ultraviolet lithography(EUVL)has been demonstrated to meet the industrial requirements of new-generation semiconductor fabrication.The development of high-power EUV sources is a long-term critical challenge to the implementation of EUVL in high-volume manufacturing(HVM),together with other technologies such as photoresist and mask.Historically,both theoretical studies and experiments have clearly indicated that the CO 2 laser-produced plasma(LPP)system is a promising solution for EUVL source,able to realize high conversion efficiency(CE)and output power.Currently,ASML’s NXE:3400B EUV scanner configuring CO_(2) LPP source sys-tem has been installed and operated at chipmaker customers.Mean-while,other research teams have made different progresses in the development of LPP EUV sources.However,in their technologies,some critical areas need to be further improved to meet the requirements of 5 nm node and below.Critically needed improvements include higher laser power,stable droplet generation system and longer collector life-time.In this paper,we describe the performance characteristics of the laser system,droplet generator and mirror collector for different EUV sources,and also the new development results.
基金financially supported by the National Natural Science Foundation of China(No.51204037)
文摘Extracting B2O3 from calcined boron mud(CBM) was studied. The effect of factors such as reaction temperature and NaO H-to-CBM mass ratio on B2O3 extraction efficiency was investigated. The results show that increasing reaction temperature and NaO H-to-CBM mass ratio increases B2O3 extraction efficiency. There are two stages for the B2O3 extracting process: 0–20 min is the first stage, which is rapid; 20–50 min is the second stage, which is slower than the first stage. The overall extracting process follows the shrinking core model, and the first and second stages are determined to obey the surface chemical reaction model and the diffusion through the products layer model,respectively. The activation energies of the first and second stages are calculated to be 41.74 and 15.43 kJ·mol-1,respectively. The B2O3 extracting kinetics equations of the first and second stages are also obtained.
基金financially supported by the National Basic Research Program of China (No.2014CB6434085)
文摘Nickel leaching from low-grade nickel matte(LGNM) using aqueous ferric chloride solution was studied.The influence of factors such as leaching temperature and concentration of ferric chloride on the nickel leaching ratio was investigated.The results show that increasing leaching temperature and concentration of ferric chloride increases the nickel leaching ratio.The overall nickel leaching process follows the unreacted shrinking core model,and the surface chemical reaction is the rate-controlling step.The activation energy and the reaction order of the nickel leaching process,controlled by the surface chemical reaction,were calculated to be 52.96 kJ mol^(-1)and 0.5,respectively.Therefore,the kinetics equation for the nickel leaching was found to be 1-(1-α)^(1/3)=7.18×10~4C^(0.5)exp[-52,960/(RT)]t.
基金Projects(51404057,50874026)supported by the National Natural Science Foundation of ChinaProject(N150204014)supported by Fundamental Research Funds for the Central Universities,China
文摘NbC-Sn composite powder was successfully prepared from SnO2,Nb2O5and carbon by electrochemical reduction andcarbonization in CaCl2-NaCl molten salt at900°C.The reaction pathway was investigated by terminating electrochemicalexperiments for various durations.The influence of carbon on the final products was considered.NbC particles were obtained byleaching the composite with acid.The results showed that the aggregated NbC-Sn composite powdev contained NbC particles about50-100nm and Sn particles about200nm.SnO2was reduced to Sn in the sintering process.Nb2O5was electrochemically reduced toNb in molten salt,experiencing some intermediate products of calcium niobates and niobium suboxides.Nb metal obtained wasconverted to NbC with assistance of carbon.The reduction of Nb oxides may be incomplete and Nb3Sn would be formed if carbon isinsufficient in the cathodic pellet.NbC with good dispersity is produced by leaching NbC-Sn with HCl.
基金financially supported by the Fundamental Research Funds for the Central Universities (No.N172505002)the National Natural Science Foundation of China (No.51704060)+1 种基金the National Thousand Youth Talent Program of Chinathe 111 Project (No.B16009)。
文摘The formation of a rust layer on iron and steels surfaces accelerates their degradation and eventually causes material failure.In addition to fabricating a protective layer or using a sacrificial anode, repairing or removing the rust layer is another way to reduce the corrosion rate and extend the lifespans of iron and steels.Herein, an electrochemical healing approach was employed to repair the rust layer in molten Na_(2)CO_(3)-K_(2)CO_(3).The rusty layers on iron rods and screws were electrochemically converted to iron in only several minutes and a metallic luster appeared.Scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS) analyses showed that the structures of the rust layer after healing were slightly porous and the oxygen content reached a very low level.Thus, high-temperature molten-salt electrolysis may be an effective way to metalize iron rust of various shapes and structures in a short time, and could be used in the repair of cultural relics and even preparing a three-dimensional porous structures for other applications.
