Ni–48.5at%Ti thin films were irradiated in the austenite phase by different energy-level protons at a dose rate of 1.85×1012 p/(cm2·s),and the total dose was 2.0×1016 p/cm2.The microstructures of the t...Ni–48.5at%Ti thin films were irradiated in the austenite phase by different energy-level protons at a dose rate of 1.85×1012 p/(cm2·s),and the total dose was 2.0×1016 p/cm2.The microstructures of the thin films before and after irradiation were evaluated by transmission electron microscopy(TEM)and grazing-incidence X-ray diffraction(GIXRD),which showed that the volume fraction of Ti3Ni4 phase elevated with proton energy level.The influence of proton irradiation on the transformation behavior of the TiNi thin films was investigated by differential scanning calorimetry(DSC).Compared with the unirradiation film,the reverse transformation start temperatures(As)decreased by about 3°C after 120 keV proton-irradiation.The proton irradiation also had a significant effect on the mechanical properties of the TiNi thin films.After 120 keV energy proton-irradiation,the fracture strength increased by 8.44%,and the critical stress increased by 21.1%.In addition,the nanoindenter measurement image showed that the hardness of the thin films increased with the increase of proton-irradiation energy.This may be due to the defects caused by irradiation,which strengthen the matrix.展开更多
In the present study, it is expected to tailor the microstructural features, martensitic transformation temperatures and mechanical properties of Ti-V-Al shape memory alloys through adding Sn alloying elements, which ...In the present study, it is expected to tailor the microstructural features, martensitic transformation temperatures and mechanical properties of Ti-V-Al shape memory alloys through adding Sn alloying elements, which further expands their applications. Sn addition results in the monotonous rising of average valence electron number (e/a). In proportion, the single α″ martensite phase directly evolves into merely β parent phase in present Ti-V-Al-based shape memory alloys, as Sn content increases from 0.5 to 5.0 at.%. Meanwhile, Sn addition causes the reduction in the grain size. Combined with transmission electron microscopy (TEM) observation and d electron theory analysis, it can be speculated that Sn addition can suppress the precipitation of ω phase. With increasing Sn content, fracture strength invariably decreases from 962 to 792 MPa, whereas the yield strength firstly decreases and then increases. The lowest yield stress for the stress-induced martensitic transformation of 220 MPa can be obtained in Ti-V-Al shape memory alloy by adding 3.0 at.% Sn. By optimizing 1.0 at.% Sn, the excellent ductility with a largest elongation of 42.1% can be gained in Ti-V-Al shape memory alloy, which is larger than that of the reported Ti-V-Al-based shape memory alloys. Besides, as a result of solution strengthening and grain refinement, Ti-V-Al-based shape memory alloy with 5.0 at.% Sn possesses the highest yield strength, further contributing to the excellent strain recovery characteristics with 4% fully recoverable strain.展开更多
To the Editor:Alcohol dependence is a severe mental disorder that can have devastating physical and psychological impacts on patients.Alcohol dependence is reported to be one of the leading causes of death among peopl...To the Editor:Alcohol dependence is a severe mental disorder that can have devastating physical and psychological impacts on patients.Alcohol dependence is reported to be one of the leading causes of death among people aged between 15 and 49 years.[1] Thus,comprehensive interventions are important for reducing mortality and disability among patients with alcohol dependence.[2]展开更多
Isolating reductive silver kernel from shell is a challenging task but is quite important to understand the embryonic form during the formation of silver nanoclusters.The intercalation of suitable anionic species may ...Isolating reductive silver kernel from shell is a challenging task but is quite important to understand the embryonic form during the formation of silver nanoclusters.The intercalation of suitable anionic species may be of benefit for passivating then capturing such highly active kernel.Herein,we successfully isolated a novel silver thiolate nanocluster[Ag_(13)@Ag_(76)S_(16)(Cyh S)_(42)(p-NH_(2)-Ph As O_(3))_(4)]^(3+)(SD/Ag89 a,Cyh SH=cyclohexanethiol)that contains a well-isolated icosahedral Ag_(13) kernel passivated by four Ag S_(4)^(7-) tetrahedra and four p-NH_(2) Ph As O_(3)^(2-) piercing from outer Ag_(72) shell.Of note,this Ag_(13) kernel is the largest isolable subvalent silver kernel beneath the silver shell with extremely legible core-shell boundary ever before and represents a precise embryonic model formed in the reducing Ag(I)to Ag(0)followed by aggregating to large silver nanoparticles.The reductive role of DMF and the introduction of anionic passivation layer(APL)synergistically modulate the reduction kinetics,facilitating the capture of ultrasmall subvalent silver kernel.SD/Ag89 a emits in near infrared(NIR)region(λ_(em)=800 nm)at low temperature.The synthetic strategy shown in this work opens up new opportunities for precisely capturing and recognizing diverse reductive silver kernels in different systems.展开更多
Unlike the facile modulation of surface structure through protecting ligands,the core shielded by outer shell of silver nanoclusters is still hard to be controlled.Ligand effects may seep into the incipient growth of ...Unlike the facile modulation of surface structure through protecting ligands,the core shielded by outer shell of silver nanoclusters is still hard to be controlled.Ligand effects may seep into the incipient growth of silver core.However,the comparable cases to validate such hypothesis are currently lacking.Herein,we shed light on two core-shell silver nanoclusters,Ag_(7)S_(6)@Ag_(48)(SD/Ag55b,SD=SunDi)and Ag_(6)S_(6)@Ag_(48)(SD/Ag54b),differing in only one silver atom in the core which varies from a pentagon-bipyramidal Ag_(7)to an octahedral Ag_(6)while keeping the Ag_(48)shielding shell almost the same.Although no direct bonding between alkynes and silver core is observed in them,we propose that the ligand effect still exerts profound influences on the size and geometry of silver core.The solution behaviours and complete ligand-exchange reaction of SD/Ag55b in CH_(2)Cl_(2)are investigated using electrospray ionization mass spectrometry.Due to more and stronger argentophilic interactions,SD/Ag55b exhibits room-temperature phosphorescence with a 40 nm red-shift compared to that of SD/Ag54b in CH_(2)Cl_(2).This work not only presents effective fabrication of silver nanoclusters via synergism of dithiophosphate and alkyne ligands,but also provides us a pair of comparable examples to understand substitution group effect of protecting ligand on the core structures and properties.展开更多
Although inorganic anion templates are highly appreciated in the synthesis of nanosized silver clusters,supramolecular clusters used as templates to mold silver nanoclusters remain as-yet-unknown due to their existenc...Although inorganic anion templates are highly appreciated in the synthesis of nanosized silver clusters,supramolecular clusters used as templates to mold silver nanoclusters remain as-yet-unknown due to their existence as volatile forms in solution.Here,we report the synthesis of a novel silver-thiolate nanocluster(SD/Ag58a),comprising an outer tetrahedral cage of 58 silver atoms and a central supramolecular cluster[CH_(3)OH@(SO_(4))_(4)(H_(2)O)6]8−(hereafter abbreviated as CS_(4)H_(6)).Ternary CS_(4)H_(6) cluster was constructed from an(SO_(4))_(4) tetrahedron encaging one CH_(3)OH molecule inside and six water molecules sitting between paired SO_(4)^(2−)ions to form the[SO_(4)…H_(2)O…SO_(4)]hydrogen bonds(H-bonds).Also,the CS4H6 could coordinate to the inner wall of the Ag58 cage by forming Ag-O bonds,exerting templating effect on the formation of SD/Ag58a.Moreover,SD/Ag58a showed a photocurrent response upon visible light irradiation and emitted luminescence in the near-infrared(NIR)region at a cryogenic temperature.This work exemplifies the ternary supramolecule templating effect in the construction of silver nanocluster and facilitates understanding of the structure of complex solvated anion cluster in atomic precision.展开更多
In order to attain high-quality Ti-Ni-Cu film,the surface morphologies,chemical compositions and mechanical properties of Ti-Ni-Cu thin films prepared by direct current(DC)magnetron sputtering at various processes wer...In order to attain high-quality Ti-Ni-Cu film,the surface morphologies,chemical compositions and mechanical properties of Ti-Ni-Cu thin films prepared by direct current(DC)magnetron sputtering at various processes were characterized by scanning electron microscopy(SEM),X-ray diffractometer(XRD)and tensile tests.The type of substrates,Ar pressure and sputtering power had significant effects on the quality and chemical composition of Ti-Ni-Cu thin film.Compared with Si and SiO_(2) slides,it was easier to obtain freestanding films by adopting glass or piezoid slide as substrates.The Ti-Ni-Cu thin film deposited at lower pressure(0.10 Pa)had a better density.The surface was featured with porous structure in the Ti-Ni-Cu thin film prepared by higher Ar pressure of 0.36 Pa.In addition,both the tensile strength and strain of annealed Ti-Ni-Cu thin film continuously increased with Ar pressure decreasing.Higher density contributed to the superior mechanical properties.The deposition rate firstly increased and then decreased with Ar pressure and sputtering power increasing.The composition of deposited Ti-Ni-Cu film can be tailored by changing sputter power.The deposited Ti-Ni-Cu thin films at different processing parameters were in amorphous state.In short,the present study offered the important theoretical basis for the preparation of Ti-Ni-Cu thin film with higher quality and performance.展开更多
基金the National Key Research and Development Program of China(No.2018YFC1903400)the Key Program for International S&T Cooperation Projects of China(No.2021YFE0106800)+1 种基金the National Natural Science Foundation of China(Nos.52164020,52174248)the Science and Technology Research Project of Education Department of Jiangxi Province,China(No.GJJ190442).
基金partial financial support from the National Natural Science Foundation of China (No. 52101231)the Science Fund of Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing,China (No. AMGM2021F09)the Natural Science Foundation of Shandong Province,China (No. ZR2021QE044)。
基金financial supports from the National Natural Science Foundation of China(Nos.U2067201,51774328)the Key Program for International S&T Cooperation Projects of China(No.2021YFE0106800)+2 种基金the Science Fund for Distinguished Young Scholars of Hunan Province,China(No.2020JJ2044)the Young Elite Scientists Sponsorship Program by Hunan province of China(No.2018RS3011)the National 111 Project of China(No.B14034)。
基金the National Natural Science Foundation of China(Nos.51571074 and 51731005)the Industrial Transformation and Upgrading of Strong Base Project of China(No.TC150B5C0/03).
文摘Ni–48.5at%Ti thin films were irradiated in the austenite phase by different energy-level protons at a dose rate of 1.85×1012 p/(cm2·s),and the total dose was 2.0×1016 p/cm2.The microstructures of the thin films before and after irradiation were evaluated by transmission electron microscopy(TEM)and grazing-incidence X-ray diffraction(GIXRD),which showed that the volume fraction of Ti3Ni4 phase elevated with proton energy level.The influence of proton irradiation on the transformation behavior of the TiNi thin films was investigated by differential scanning calorimetry(DSC).Compared with the unirradiation film,the reverse transformation start temperatures(As)decreased by about 3°C after 120 keV proton-irradiation.The proton irradiation also had a significant effect on the mechanical properties of the TiNi thin films.After 120 keV energy proton-irradiation,the fracture strength increased by 8.44%,and the critical stress increased by 21.1%.In addition,the nanoindenter measurement image showed that the hardness of the thin films increased with the increase of proton-irradiation energy.This may be due to the defects caused by irradiation,which strengthen the matrix.
基金financial support from the National Natural Science Foundation of China(Nos.52101231,52101232 and 51871079)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing(Yantai)(No.AMGM2021F09)+1 种基金the Natural Science Foundation of Shandong Province,China(No.ZR2021QE044)the Gansu Province Science and Technology Foundation for Youths(No.21JR7RA088).
文摘In the present study, it is expected to tailor the microstructural features, martensitic transformation temperatures and mechanical properties of Ti-V-Al shape memory alloys through adding Sn alloying elements, which further expands their applications. Sn addition results in the monotonous rising of average valence electron number (e/a). In proportion, the single α″ martensite phase directly evolves into merely β parent phase in present Ti-V-Al-based shape memory alloys, as Sn content increases from 0.5 to 5.0 at.%. Meanwhile, Sn addition causes the reduction in the grain size. Combined with transmission electron microscopy (TEM) observation and d electron theory analysis, it can be speculated that Sn addition can suppress the precipitation of ω phase. With increasing Sn content, fracture strength invariably decreases from 962 to 792 MPa, whereas the yield strength firstly decreases and then increases. The lowest yield stress for the stress-induced martensitic transformation of 220 MPa can be obtained in Ti-V-Al shape memory alloy by adding 3.0 at.% Sn. By optimizing 1.0 at.% Sn, the excellent ductility with a largest elongation of 42.1% can be gained in Ti-V-Al shape memory alloy, which is larger than that of the reported Ti-V-Al-based shape memory alloys. Besides, as a result of solution strengthening and grain refinement, Ti-V-Al-based shape memory alloy with 5.0 at.% Sn possesses the highest yield strength, further contributing to the excellent strain recovery characteristics with 4% fully recoverable strain.
文摘To the Editor:Alcohol dependence is a severe mental disorder that can have devastating physical and psychological impacts on patients.Alcohol dependence is reported to be one of the leading causes of death among people aged between 15 and 49 years.[1] Thus,comprehensive interventions are important for reducing mortality and disability among patients with alcohol dependence.[2]
基金supported by the National Natural Science Foundation of China(91961105,21822107,21827801)the Fok Ying Tong Education Foundation(171009)+3 种基金the Natural Science Foundation of Shandong Province(ZR2019ZD45,JQ201803,ZR2020ZD35)the Taishan Scholar Project of Shandong Province of China(tsqn201812003,ts20190908)the Qilu Youth Scholar Funding of Shandong UniversityProject for Scientific Research Innovation Team of Young Scholar in Colleges and Universities of Shandong Province(2019KJC028)。
文摘Isolating reductive silver kernel from shell is a challenging task but is quite important to understand the embryonic form during the formation of silver nanoclusters.The intercalation of suitable anionic species may be of benefit for passivating then capturing such highly active kernel.Herein,we successfully isolated a novel silver thiolate nanocluster[Ag_(13)@Ag_(76)S_(16)(Cyh S)_(42)(p-NH_(2)-Ph As O_(3))_(4)]^(3+)(SD/Ag89 a,Cyh SH=cyclohexanethiol)that contains a well-isolated icosahedral Ag_(13) kernel passivated by four Ag S_(4)^(7-) tetrahedra and four p-NH_(2) Ph As O_(3)^(2-) piercing from outer Ag_(72) shell.Of note,this Ag_(13) kernel is the largest isolable subvalent silver kernel beneath the silver shell with extremely legible core-shell boundary ever before and represents a precise embryonic model formed in the reducing Ag(I)to Ag(0)followed by aggregating to large silver nanoparticles.The reductive role of DMF and the introduction of anionic passivation layer(APL)synergistically modulate the reduction kinetics,facilitating the capture of ultrasmall subvalent silver kernel.SD/Ag89 a emits in near infrared(NIR)region(λ_(em)=800 nm)at low temperature.The synthetic strategy shown in this work opens up new opportunities for precisely capturing and recognizing diverse reductive silver kernels in different systems.
基金supported by the National Natural Science Foundation of China(91961105,21822107)the Fok Ying Tong Education Foundation(171009)+3 种基金the Natural Science Foundation of Shandong Province(ZR2019ZD45,ZR2020ZD35,JQ201803,ZR2017MB061)the Taishan Scholar Project of Shandong Province of China(tsqn201812003,ts20190908)the Qilu Youth Scholar Funding of Shandong UniversityProject for Scientific Research Innovation Team of Young Scholar in Colleges and Universities of Shandong Province(2019KJC028)。
文摘Unlike the facile modulation of surface structure through protecting ligands,the core shielded by outer shell of silver nanoclusters is still hard to be controlled.Ligand effects may seep into the incipient growth of silver core.However,the comparable cases to validate such hypothesis are currently lacking.Herein,we shed light on two core-shell silver nanoclusters,Ag_(7)S_(6)@Ag_(48)(SD/Ag55b,SD=SunDi)and Ag_(6)S_(6)@Ag_(48)(SD/Ag54b),differing in only one silver atom in the core which varies from a pentagon-bipyramidal Ag_(7)to an octahedral Ag_(6)while keeping the Ag_(48)shielding shell almost the same.Although no direct bonding between alkynes and silver core is observed in them,we propose that the ligand effect still exerts profound influences on the size and geometry of silver core.The solution behaviours and complete ligand-exchange reaction of SD/Ag55b in CH_(2)Cl_(2)are investigated using electrospray ionization mass spectrometry.Due to more and stronger argentophilic interactions,SD/Ag55b exhibits room-temperature phosphorescence with a 40 nm red-shift compared to that of SD/Ag54b in CH_(2)Cl_(2).This work not only presents effective fabrication of silver nanoclusters via synergism of dithiophosphate and alkyne ligands,but also provides us a pair of comparable examples to understand substitution group effect of protecting ligand on the core structures and properties.
基金supported financially by the National Natural Science Foundation of China(grant nos.91961105,21822107,21571115,and 21827801)the Fok Ying Tong Education Foundation(grant no.171009)+3 种基金the Natural Science Foundation of Shandong Province(grant nos.ZR2020ZD35,ZR2019ZD45,JQ201803,and ZR2017MB061)the Taishan Scholar Project of Shandong Province of China(grant nos.tsqn201812003 and ts20190908)the Qilu Youth Scholar Funding of Shandong UniversityProject for Scientific Research Innovation Team of Young Scholar in Colleges and Universities of Shandong Province(grant no.2019KJC028).
文摘Although inorganic anion templates are highly appreciated in the synthesis of nanosized silver clusters,supramolecular clusters used as templates to mold silver nanoclusters remain as-yet-unknown due to their existence as volatile forms in solution.Here,we report the synthesis of a novel silver-thiolate nanocluster(SD/Ag58a),comprising an outer tetrahedral cage of 58 silver atoms and a central supramolecular cluster[CH_(3)OH@(SO_(4))_(4)(H_(2)O)6]8−(hereafter abbreviated as CS_(4)H_(6)).Ternary CS_(4)H_(6) cluster was constructed from an(SO_(4))_(4) tetrahedron encaging one CH_(3)OH molecule inside and six water molecules sitting between paired SO_(4)^(2−)ions to form the[SO_(4)…H_(2)O…SO_(4)]hydrogen bonds(H-bonds).Also,the CS4H6 could coordinate to the inner wall of the Ag58 cage by forming Ag-O bonds,exerting templating effect on the formation of SD/Ag58a.Moreover,SD/Ag58a showed a photocurrent response upon visible light irradiation and emitted luminescence in the near-infrared(NIR)region at a cryogenic temperature.This work exemplifies the ternary supramolecule templating effect in the construction of silver nanocluster and facilitates understanding of the structure of complex solvated anion cluster in atomic precision.
基金financially supported by the National Natural Science Foundation of China(Nos.51801023,51871080 and 51571073)the Industrial Transformation&Upgrading of Strong Base Project of China(No.TC150B5C0/03)。
文摘In order to attain high-quality Ti-Ni-Cu film,the surface morphologies,chemical compositions and mechanical properties of Ti-Ni-Cu thin films prepared by direct current(DC)magnetron sputtering at various processes were characterized by scanning electron microscopy(SEM),X-ray diffractometer(XRD)and tensile tests.The type of substrates,Ar pressure and sputtering power had significant effects on the quality and chemical composition of Ti-Ni-Cu thin film.Compared with Si and SiO_(2) slides,it was easier to obtain freestanding films by adopting glass or piezoid slide as substrates.The Ti-Ni-Cu thin film deposited at lower pressure(0.10 Pa)had a better density.The surface was featured with porous structure in the Ti-Ni-Cu thin film prepared by higher Ar pressure of 0.36 Pa.In addition,both the tensile strength and strain of annealed Ti-Ni-Cu thin film continuously increased with Ar pressure decreasing.Higher density contributed to the superior mechanical properties.The deposition rate firstly increased and then decreased with Ar pressure and sputtering power increasing.The composition of deposited Ti-Ni-Cu film can be tailored by changing sputter power.The deposited Ti-Ni-Cu thin films at different processing parameters were in amorphous state.In short,the present study offered the important theoretical basis for the preparation of Ti-Ni-Cu thin film with higher quality and performance.
