Incorporating metal nanodots(NDs)into heterostructures for high charge separation and transfer capacities is one of the most effective strategies for improving their photocatalytic activities.However,controlling the s...Incorporating metal nanodots(NDs)into heterostructures for high charge separation and transfer capacities is one of the most effective strategies for improving their photocatalytic activities.However,controlling the space distribution of metal NDs for optimizing charge transport pathways remains a significant challenge,particularly in two-dimensional(2D)face-to-face heterostructures.Herein,we develop a simple targeted self-reduction strategy for selectively loading Ru NDs onto the Ti_(3−x)C_(2)T_(y)(TC)surface of 2D TC/g-C_(3)N_(4)(CN)heterojunction based on the reductive Ti vacancy defects creatively increased during the preparation of TC/CN by reducing calcination.Notably,the optimized Ru/TC/CN photocatalyst exhibits an outstanding H_(2)evolution rate of 3.21 mmol·g^(−1)·h^(−1)and a high apparent quantum efficiency of 30.9%at 380 nm,which is contributed by the unidirectional transfer of the photogenerated electrons from CN to Ru active sites(CN→TC→Ru)and the suppressed backflow of electrons from Ru sites to CN,as revealed by comprehensive characterizations and density functional theory(DFT)calculations.This work provides a novel strategy for synthesizing the highly efficient photocatalysts with a controllable charge transfer paths,which will boost the development of photocatalysis.展开更多
KTi_(2)(PO_(4))_(3)is a promising anode material for potassium storage,but suffers from low conductivity and difficult balance between high capacity and good structural stability.Herein,the Ti_(3)C_(2)T_(x)MXene is us...KTi_(2)(PO_(4))_(3)is a promising anode material for potassium storage,but suffers from low conductivity and difficult balance between high capacity and good structural stability.Herein,the Ti_(3)C_(2)T_(x)MXene is used as a multifunctional binder to fabricate the KTi_(2)(PO_(4))_(3)electrode by the traditional homogenizing-coating method.The MXene nanosheets,together with the conductive agent super P nanoparticles,construct a multiple conductive network for fast electron/ion transfer and high electrochemical kinet-ics.Moreover,the network ensures the structural stability of the KTi_(2)(PO_(4))_(3)electrode during the de-intercalation/intercalation of 4 K^(+)ions,which is beneficial for simultaneously achieving high capacity and good cycle performance.Therefore,the MXene-bonded KTi_(2)(PO_(4))_(3)electrode delivers a reversible capacity of 255.2 mAh/g at 50 mA/g,outstanding rate capability with 132.3 mAh/g at 2 A/g,and ex-cellent cycle performance with 151.6 mAh/g at 1 A/g after 2000 cycles.This work not only suggests a high-performance anode material for potassium-ion batteries,but also demonstrates that the MXene is a promising binder material for constructing conductive electrodes in rechargeable batteries.展开更多
Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) composite was easily synthesized via one-step succinct-operated hydrothermal process.The interconnected Co_(3)V_(2)O_(8)/Co_(3)O_(4) nanowires network can in-situ grow and...Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) composite was easily synthesized via one-step succinct-operated hydrothermal process.The interconnected Co_(3)V_(2)O_(8)/Co_(3)O_(4) nanowires network can in-situ grow and anchor on the surface of Ti_(3)C_(2)T_(x) via the strong Co-F bonds and contribute tremendously to depress Ti_(3)C_(2)T_(x) self-restacking.Profiting from the synergistically interplayed effect among the multiple interfaces and high conductivity of Ti_(3)C_(2)T_(x) as well as outstanding stability of the as-designed nanostructure,the optimum Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x)electrode reaches a commendable specific capacitance(up to 3800 mF·cm^(−2)),great rate capability(80%capacitance retention after 20-times current increasing),and preeminent cycling stability(95.4%/85.5%retention at 7000th/20,000th cycle).Moreover,the all-solid-state asymmetric supercapacitor based on Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) and active carbon can deliver a high energy density of 84.0μWh·cm^(−2) at the power energy of 3.2 mW·cm^(−2),and excellent cycling durability with 87.0%of initial capacitance retention upon 20,000 loops.This work provides a practicable pathway to tailor MXene-based composites for high-performance supercapacitor.展开更多
Microwave dielectric ceramics(MWDCs)with low dielectric constant and low dielectric loss are desired in contemporary society,where the communication frequency is developing to high frequency(sub-6G).Herein,Nd_(2)(Zr_(...Microwave dielectric ceramics(MWDCs)with low dielectric constant and low dielectric loss are desired in contemporary society,where the communication frequency is developing to high frequency(sub-6G).Herein,Nd_(2)(Zr_(1−x)Ti_(x))_(3)(MoO_(4))_(9)(NZ_(1−x)T_(x)M,x=0.02-0.10)ceramics were prepared through a solid-phase process.According to X-ray diffraction(XRD)patterns,the ceramics could form a pure crystal structure with the R3c(167)space group.The internal parameters affecting the properties of the ceramics were calculated and analyzed by employing Clausius-Mossotti relationship,Shannon’s rule,and Phillips-van Vechten-Levine(P-V-L)theory.Furthermore,theoretical dielectric loss of the ceramics was measured and analyzed by a Fourier transform infrared(IR)radiation spectrometer.Notably,when x=0.08 and sintered at 700℃,optimal microwave dielectric properties of the ceramics were obtained,including a dielectric constant(ε_(r))=10.94,Q·f=82,525 GHz(at 9.62 GHz),and near-zero resonant frequency temperature coefficient(τ_(f))=−12.99 ppm/℃.This study not only obtained an MWDC with excellent properties but also deeply analyzed the effects of Ti^(4+)on the microwave dielectric properties and chemical bond characteristics of Nd_(2)Zr_(3)(MoO_(4))_(9)(NZM),which laid a solid foundation for the development of rare-earth molybdate MWDC system.展开更多
Flexible multifunctional polymer-based electromagnetic interference(EMI)shielding composite films have important application values in the fields of 5G communication technology,wearable electronic devices and artifici...Flexible multifunctional polymer-based electromagnetic interference(EMI)shielding composite films have important application values in the fields of 5G communication technology,wearable electronic devices and artificial intelligence.In this work,Fe_(3)O_(4)/polyamic acid(PAA)nanofiber films are prepared by in-situ polymerization and electrospinning technology,and Ti_(3)C_(2)T_(x)nanosheets are deposited on the surface of the Fe_(3)O_(4)/PAA nanofiber films via vacuum-assisted filtration.Then,Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/polyimide(PI))composite films are obtained by thermal imidization.The two sides of the Janus films exhibit completely different properties.The Fe_(3)O_(4)/PI side has excellent hydrophobicity and insulation property,and the Ti_(3)C_(2)T_(x)side has hydrophilicity and terrific conductivity.When the mass fraction of Ti_(3)C_(2)T_(x)is 80 wt.%,the Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/PI)composite film has excellent EMI shielding performances and mechanical properties,with EMI shielding effectiveness,tensile strength and Young’s modulus reaching 66 dB,114.5 MPa and 5.8 GPa,respectively.At the same time,electromagnetic waves show different absorption shielding effectiveness(SEA)when incident from two sides of the Janus films.When the electromagnetic waves are incident from the Fe_(3)O_(4)/PI side,the SEA of the Janus film is 58 dB,much higher than that when the electromagnetic waves are incident from the Ti_(3)C_(2)T_(x)side(39 dB).In addition,the Ti_(3)C_(2)T_(x)side of the Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/PI)composite films also has excellent electrothermal and photothermal conversion performances.When the applied voltage is 4 V,the stable surface temperature reaches 108°C;when it is irradiated by simulated sunlight with power density of 200 mW/cm2,the stable surface temperature reaches 95℃.展开更多
Surface-enhanced Raman scattering(SERS)spectroscopy has been employed as a rapid analysis technology for food security inspection recently.Nowadays,it is still a great challenge to rapidly quantify multiple trace anti...Surface-enhanced Raman scattering(SERS)spectroscopy has been employed as a rapid analysis technology for food security inspection recently.Nowadays,it is still a great challenge to rapidly quantify multiple trace antibiotics potentially abused in aquaculture industry.In this work,a magnetic Ti_(3)C_(2)T_(x)/Fe_(3)O_(4)/Ag substrate was prepared for the development of a reliable rapid SERS quantification method for multiple trace sulfonamides in aquatic products.This magnetic substrate had good uniformity,reproducibility,stability and SERS activity.Moreover,this substrate could integrate the magnetic separation-enrichment and matrix clean-up without cross contamination,which endowed it with good selectivity and antiinterference capability during real sample analysis.The electromagnetic enhancement and chemical enhancement mechanism of this magnetic substrate were studied in detail to reveal its good separationenrichment performance and SERS activity.Finally,a rapid SERS quantification method was established and practically applied for trace phthalic sulfathiazole(PST)and silver sulfadiazine(SSD)in aquatic products by using Ti_(3)C_(2)T_(x)/Fe_(3)O_(4)/Ag magnetic substrates.Trace PST and SSD could be actually detected and quantified as 55.9μg/kg and 64.0μg/kg in aquatic products,respectively.Good recoveries of 83.9%-116%with relative standard deviations(RSDs)of 0.5%-3.2%for PST and 80.2%-102%with RSDs of 1.3%-5.8%for SSD were obtained.This work proposed an efficient and reliable method for rapid quantification of trace multiple sulfonamides in complex aquatic samples during food security inspection.展开更多
The structural and electrophysical characteristics of a number of solid solutions of layered oxides of the perovskite-type Bi_(7)Ti_(4+x)WxNb_(1-2x-0.1)V_(0.1)O_(21)(x=0.1-0.4)are studied.According to X-ray powder dif...The structural and electrophysical characteristics of a number of solid solutions of layered oxides of the perovskite-type Bi_(7)Ti_(4+x)WxNb_(1-2x-0.1)V_(0.1)O_(21)(x=0.1-0.4)are studied.According to X-ray powder diffraction data,all the compounds studied are single-phase and have the structure of Aurivillius phases(m=2.5)with a rhombic crystal lattice(space group I2 cm,Z=2).Changes in tetragonal and rhombic distortions of perovskite-like layers in compounds were considered depending on their chemical composition.The temperature dependences of the relative permittivityε(T)were measured.It was shown that the Curie temperature T_(C) of the perovskite-type oxides Bi_(7)Ti_(4+x)WxNb_(1-2x-0.1)V_(0.1)O_(21)(x=0.1-0.4)linearly decreases with increasing parameter x.The activation energies of charge carriers were obtained in different temperature ranges.It was found that there are three temperature regions with very different activation energies due to the different nature of the charge carriers in the studied compounds.The effect of substitution of Nb^(5+) ions by V^(5+) ions is investigated.It was found that for a number of compounds,the substitution of niobium ions by vanadium ions led to an increase in the dielectric constant and a decrease in the dielectric loss tangent.展开更多
By means of improved ligand-field theory, the 'pure electronic'presure-induced shifts (PS's) and the PS's due to electron-phonon interaction (EPI) of the R_1, R_2,B_1, B_2, B_3, and R′_3 lines and the...By means of improved ligand-field theory, the 'pure electronic'presure-induced shifts (PS's) and the PS's due to electron-phonon interaction (EPI) of the R_1, R_2,B_1, B_2, B_3, and R′_3 lines and the ground-state zero-Geld-splitting of ruby have been uniformlycalculated. The calculation results are in very good agreement with all the experimental data. Atnormal pressure, ruby is a crystal with very strong crystal field. Thus, the admixture of ∣t_2~2(~3T_1)e~4T_2 】 and ∣t_2~(32)E＞ bases in the wavefunction of R_1 level of ruby is small at normalpressure, and it gradually decreases with increasing pressure, which causes the R_1-line PS of rubyto monotonously red shift with approximate linearity. The combined effect of the pure electronic PSof R_1 line and the PS of R_1 line due to EPI gives rise to the total PS of R_1 line. The analysesand comparisons among the features of R_1-line PS's of three laser crystals (ruby, GSGG:Cr~(3+) andGGG:Cr~(3+)) have been made, and the origin of their difference has been revealed.展开更多
基金the National Natural Science Foundation of China(No.22002142)China Postdoctoral Science Foundation(No.2020T130605)+2 种基金Natural Science Foundation of Henan Province(No.202300410436)Support Plan for College Science and Technology Innovation Team of Henan Province(No.16IRTSTHN001)the Science&Technology Innovation Talent Plan of Henan Province(No.174200510018).
文摘Incorporating metal nanodots(NDs)into heterostructures for high charge separation and transfer capacities is one of the most effective strategies for improving their photocatalytic activities.However,controlling the space distribution of metal NDs for optimizing charge transport pathways remains a significant challenge,particularly in two-dimensional(2D)face-to-face heterostructures.Herein,we develop a simple targeted self-reduction strategy for selectively loading Ru NDs onto the Ti_(3−x)C_(2)T_(y)(TC)surface of 2D TC/g-C_(3)N_(4)(CN)heterojunction based on the reductive Ti vacancy defects creatively increased during the preparation of TC/CN by reducing calcination.Notably,the optimized Ru/TC/CN photocatalyst exhibits an outstanding H_(2)evolution rate of 3.21 mmol·g^(−1)·h^(−1)and a high apparent quantum efficiency of 30.9%at 380 nm,which is contributed by the unidirectional transfer of the photogenerated electrons from CN to Ru active sites(CN→TC→Ru)and the suppressed backflow of electrons from Ru sites to CN,as revealed by comprehensive characterizations and density functional theory(DFT)calculations.This work provides a novel strategy for synthesizing the highly efficient photocatalysts with a controllable charge transfer paths,which will boost the development of photocatalysis.
基金support by National Natural Science Foundation of China(No.U2004212).
文摘KTi_(2)(PO_(4))_(3)is a promising anode material for potassium storage,but suffers from low conductivity and difficult balance between high capacity and good structural stability.Herein,the Ti_(3)C_(2)T_(x)MXene is used as a multifunctional binder to fabricate the KTi_(2)(PO_(4))_(3)electrode by the traditional homogenizing-coating method.The MXene nanosheets,together with the conductive agent super P nanoparticles,construct a multiple conductive network for fast electron/ion transfer and high electrochemical kinet-ics.Moreover,the network ensures the structural stability of the KTi_(2)(PO_(4))_(3)electrode during the de-intercalation/intercalation of 4 K^(+)ions,which is beneficial for simultaneously achieving high capacity and good cycle performance.Therefore,the MXene-bonded KTi_(2)(PO_(4))_(3)electrode delivers a reversible capacity of 255.2 mAh/g at 50 mA/g,outstanding rate capability with 132.3 mAh/g at 2 A/g,and ex-cellent cycle performance with 151.6 mAh/g at 1 A/g after 2000 cycles.This work not only suggests a high-performance anode material for potassium-ion batteries,but also demonstrates that the MXene is a promising binder material for constructing conductive electrodes in rechargeable batteries.
基金This study was financially supported by the National Science Foundation of China(No.52201254)the National Science Foundation of Shandong Province(Nos.ZR2020MB090 and ZR2020QE012)+1 种基金the Project of“20 Items of University”of Jinan(No.202228046)Taishan Scholar Project of Shandong Province.
文摘Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) composite was easily synthesized via one-step succinct-operated hydrothermal process.The interconnected Co_(3)V_(2)O_(8)/Co_(3)O_(4) nanowires network can in-situ grow and anchor on the surface of Ti_(3)C_(2)T_(x) via the strong Co-F bonds and contribute tremendously to depress Ti_(3)C_(2)T_(x) self-restacking.Profiting from the synergistically interplayed effect among the multiple interfaces and high conductivity of Ti_(3)C_(2)T_(x) as well as outstanding stability of the as-designed nanostructure,the optimum Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x)electrode reaches a commendable specific capacitance(up to 3800 mF·cm^(−2)),great rate capability(80%capacitance retention after 20-times current increasing),and preeminent cycling stability(95.4%/85.5%retention at 7000th/20,000th cycle).Moreover,the all-solid-state asymmetric supercapacitor based on Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) and active carbon can deliver a high energy density of 84.0μWh·cm^(−2) at the power energy of 3.2 mW·cm^(−2),and excellent cycling durability with 87.0%of initial capacitance retention upon 20,000 loops.This work provides a practicable pathway to tailor MXene-based composites for high-performance supercapacitor.
基金supported by the National Natural Science Foundation of China (Nos.51972143 and 52272126)State Key Laboratory of New Ceramics and Fine Processing,Tsinghua University (No.KFZD202101).
文摘Microwave dielectric ceramics(MWDCs)with low dielectric constant and low dielectric loss are desired in contemporary society,where the communication frequency is developing to high frequency(sub-6G).Herein,Nd_(2)(Zr_(1−x)Ti_(x))_(3)(MoO_(4))_(9)(NZ_(1−x)T_(x)M,x=0.02-0.10)ceramics were prepared through a solid-phase process.According to X-ray diffraction(XRD)patterns,the ceramics could form a pure crystal structure with the R3c(167)space group.The internal parameters affecting the properties of the ceramics were calculated and analyzed by employing Clausius-Mossotti relationship,Shannon’s rule,and Phillips-van Vechten-Levine(P-V-L)theory.Furthermore,theoretical dielectric loss of the ceramics was measured and analyzed by a Fourier transform infrared(IR)radiation spectrometer.Notably,when x=0.08 and sintered at 700℃,optimal microwave dielectric properties of the ceramics were obtained,including a dielectric constant(ε_(r))=10.94,Q·f=82,525 GHz(at 9.62 GHz),and near-zero resonant frequency temperature coefficient(τ_(f))=−12.99 ppm/℃.This study not only obtained an MWDC with excellent properties but also deeply analyzed the effects of Ti^(4+)on the microwave dielectric properties and chemical bond characteristics of Nd_(2)Zr_(3)(MoO_(4))_(9)(NZM),which laid a solid foundation for the development of rare-earth molybdate MWDC system.
基金supports from the National Natural Science Foundation of China(Nos.U21A2093 and 51903145)Fundamental Research Funds for the Central Universities(No.D5000210627)+1 种基金Y.L.Z.would like to thank the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(No.CX2021107)This work is also financially supported by Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars.
文摘Flexible multifunctional polymer-based electromagnetic interference(EMI)shielding composite films have important application values in the fields of 5G communication technology,wearable electronic devices and artificial intelligence.In this work,Fe_(3)O_(4)/polyamic acid(PAA)nanofiber films are prepared by in-situ polymerization and electrospinning technology,and Ti_(3)C_(2)T_(x)nanosheets are deposited on the surface of the Fe_(3)O_(4)/PAA nanofiber films via vacuum-assisted filtration.Then,Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/polyimide(PI))composite films are obtained by thermal imidization.The two sides of the Janus films exhibit completely different properties.The Fe_(3)O_(4)/PI side has excellent hydrophobicity and insulation property,and the Ti_(3)C_(2)T_(x)side has hydrophilicity and terrific conductivity.When the mass fraction of Ti_(3)C_(2)T_(x)is 80 wt.%,the Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/PI)composite film has excellent EMI shielding performances and mechanical properties,with EMI shielding effectiveness,tensile strength and Young’s modulus reaching 66 dB,114.5 MPa and 5.8 GPa,respectively.At the same time,electromagnetic waves show different absorption shielding effectiveness(SEA)when incident from two sides of the Janus films.When the electromagnetic waves are incident from the Fe_(3)O_(4)/PI side,the SEA of the Janus film is 58 dB,much higher than that when the electromagnetic waves are incident from the Ti_(3)C_(2)T_(x)side(39 dB).In addition,the Ti_(3)C_(2)T_(x)side of the Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/PI)composite films also has excellent electrothermal and photothermal conversion performances.When the applied voltage is 4 V,the stable surface temperature reaches 108°C;when it is irradiated by simulated sunlight with power density of 200 mW/cm2,the stable surface temperature reaches 95℃.
基金financially supported by the National Natural Science Foundation of China(Nos.22074161 and 21976213)Guangdong Basic and Applied Basic Research Foundation(No.2019A1515010107)+3 种基金the Science and Technology Planning Project of Guangzhou City(No.202102080167)the Research and Development Plan for Key Areas of Food Safety in Guangdong Province of China(No.2019B020211001)the National Key Research and Development Program of China(No.2019YFC1606101)the State Key Program of National Natural Science of China(No.22134007)。
文摘Surface-enhanced Raman scattering(SERS)spectroscopy has been employed as a rapid analysis technology for food security inspection recently.Nowadays,it is still a great challenge to rapidly quantify multiple trace antibiotics potentially abused in aquaculture industry.In this work,a magnetic Ti_(3)C_(2)T_(x)/Fe_(3)O_(4)/Ag substrate was prepared for the development of a reliable rapid SERS quantification method for multiple trace sulfonamides in aquatic products.This magnetic substrate had good uniformity,reproducibility,stability and SERS activity.Moreover,this substrate could integrate the magnetic separation-enrichment and matrix clean-up without cross contamination,which endowed it with good selectivity and antiinterference capability during real sample analysis.The electromagnetic enhancement and chemical enhancement mechanism of this magnetic substrate were studied in detail to reveal its good separationenrichment performance and SERS activity.Finally,a rapid SERS quantification method was established and practically applied for trace phthalic sulfathiazole(PST)and silver sulfadiazine(SSD)in aquatic products by using Ti_(3)C_(2)T_(x)/Fe_(3)O_(4)/Ag magnetic substrates.Trace PST and SSD could be actually detected and quantified as 55.9μg/kg and 64.0μg/kg in aquatic products,respectively.Good recoveries of 83.9%-116%with relative standard deviations(RSDs)of 0.5%-3.2%for PST and 80.2%-102%with RSDs of 1.3%-5.8%for SSD were obtained.This work proposed an efficient and reliable method for rapid quantification of trace multiple sulfonamides in complex aquatic samples during food security inspection.
基金This work was supported by the Ministry of Science and Higher Education of the Russian Federation(State assignment in the field of scientific activity,Southern Federal University,2020).
文摘The structural and electrophysical characteristics of a number of solid solutions of layered oxides of the perovskite-type Bi_(7)Ti_(4+x)WxNb_(1-2x-0.1)V_(0.1)O_(21)(x=0.1-0.4)are studied.According to X-ray powder diffraction data,all the compounds studied are single-phase and have the structure of Aurivillius phases(m=2.5)with a rhombic crystal lattice(space group I2 cm,Z=2).Changes in tetragonal and rhombic distortions of perovskite-like layers in compounds were considered depending on their chemical composition.The temperature dependences of the relative permittivityε(T)were measured.It was shown that the Curie temperature T_(C) of the perovskite-type oxides Bi_(7)Ti_(4+x)WxNb_(1-2x-0.1)V_(0.1)O_(21)(x=0.1-0.4)linearly decreases with increasing parameter x.The activation energies of charge carriers were obtained in different temperature ranges.It was found that there are three temperature regions with very different activation energies due to the different nature of the charge carriers in the studied compounds.The effect of substitution of Nb^(5+) ions by V^(5+) ions is investigated.It was found that for a number of compounds,the substitution of niobium ions by vanadium ions led to an increase in the dielectric constant and a decrease in the dielectric loss tangent.
文摘By means of improved ligand-field theory, the 'pure electronic'presure-induced shifts (PS's) and the PS's due to electron-phonon interaction (EPI) of the R_1, R_2,B_1, B_2, B_3, and R′_3 lines and the ground-state zero-Geld-splitting of ruby have been uniformlycalculated. The calculation results are in very good agreement with all the experimental data. Atnormal pressure, ruby is a crystal with very strong crystal field. Thus, the admixture of ∣t_2~2(~3T_1)e~4T_2 】 and ∣t_2~(32)E＞ bases in the wavefunction of R_1 level of ruby is small at normalpressure, and it gradually decreases with increasing pressure, which causes the R_1-line PS of rubyto monotonously red shift with approximate linearity. The combined effect of the pure electronic PSof R_1 line and the PS of R_1 line due to EPI gives rise to the total PS of R_1 line. The analysesand comparisons among the features of R_1-line PS's of three laser crystals (ruby, GSGG:Cr~(3+) andGGG:Cr~(3+)) have been made, and the origin of their difference has been revealed.
