Introduction:To construct a set of evaluation indicators suitable for the public health system in primary and secondary schools in Beijing,this study aimed to provide a basis for objectively assessing the current stat...Introduction:To construct a set of evaluation indicators suitable for the public health system in primary and secondary schools in Beijing,this study aimed to provide a basis for objectively assessing the current status of system development and identifying future directions for improvement.Methods:An indicator pool was established based on literature reviews and expert consultation.The indicator system was then refined and finalized through two rounds of the Delphi method,and the weights of the indicators were determined using the analytic hierarchy process.Results:The expert participation rate reached 100%,and the average expert authority coefficient was 0.87.The indicator coordination coefficient W was statistically significant(P<0.001).Ultimately,an evaluation system comprising 5 first-level indicators,15 second-level indicators,and 39 third-level indicators was developed.Conclusion:The indicator system constructed in this study shows good expert consistency and credibility.It can effectively pinpoint key components of system development,providing a scientific foundation for optimizing resource allocation and supporting ongoing improvement.展开更多
Transition-metal-based chalcogenides have recently emerged as greatly promising infrared nonlinear optical(IR-NLO)candidates due to their unique structural chemistries and rich optical properties.However,Fe-based IR-N...Transition-metal-based chalcogenides have recently emerged as greatly promising infrared nonlinear optical(IR-NLO)candidates due to their unique structural chemistries and rich optical properties.However,Fe-based IR-NLO chalcogenides with phase-matching(PM)features have not yet been reported.In this work,a new non-centrosymmetric(NCS)melilite oxychalcogenide,Sr_(2)FeGe_(2)OS_(6),has been prepared by an isomorphous substitution method,and the relationships between the microscopic crystal structure and macroscopic NLO activity were systematically investigated.Sr_(2)FeGe_(2)OS_(6) adopts the tetragonal space group of P421m(no.113)and features a unique two-dimensional structure with Cairo pentagonal tiling layers formed by the alternating connection of[Ge_(2)OS_(6)]dimers and[FeS_(4)]tetrahedra via corner-sharing and with the charge-balanced Sr^(2+)cations between these layers.Excitingly,Sr_(2)FeGe_(2)OS_(6) is the first Fe-based example capable of achieving PM in the IR-NLO chalcogenide system and displays an outstanding IR-NLO comprehensive performance,including a wide energy gap(E_(g)=2.24 eV),sufficient second-harmonic-generation(SHG)efficiency(d_(eff)=5.89 pm V^(-1) at 2050 nm)and strong laser-induced damage threshold(LIDT=14.42 MW cm^(-2)).Deeper structural and theoretical analysis suggests that the ordered arrangement of NLO-active motifs,[Ge_(2)OS_(6)]dimers and[FeS_(4)]tetrahedra,makes significant contributions to the strong d_(eff) and large birefringence(Δn).This work not only demonstrates a PM Fe-based NCS material for the first time but also puts forward a new design avenue for high-performance IR-NLO materials.展开更多
Herein,a highly sensitive detection platform for the dual-mode determination of sarcosine by fluorescence and colorimetry was constructed based on zirconium-based metal organic frameworks(Zr-MOFs)with multi-enzyme imm...Herein,a highly sensitive detection platform for the dual-mode determination of sarcosine by fluorescence and colorimetry was constructed based on zirconium-based metal organic frameworks(Zr-MOFs)with multi-enzyme immobilization.Zr-MOFs with peroxidase-mimicking activity were firstly prepared by a solvothermal method,and sarcosine oxidase(SOX)and horseradish peroxidase(HRP)were simultaneously encapsulated in the Zr-MOFs to form the Zr-MOFs@SOX@HRP composite.Oxidation of sarcosine could be catalyzed by the SOX in the Zr-MOFs@SOX@HRP composite to generate hydrogen peroxide(H_(2)O_(2)).The generated H_(2)O_(2)was decomposed through the synergistic catalysis by Zr-MOFs and HRP to generate free radicals that could oxidize the chromogenic substrate p-phenylenediamine(PPD)to produce oxPPD.The oxPPD generated could quench the fluorescence of carbon dots at 510 nm via the internal filtering effect(IFE).The amount of sarcosine could be sensitively detected by monitoring the changes of the colorimetric and fluorescence signals,with detection limits of 0.44μM and 0.21μM,respectively.Thus,the dual-mode detection of sarcosine by fluorescence and colorimetry through a Zr-MOF-mediated cascade reaction system was realized.The method was applied to the determination of sarcosine in the urine of healthy individuals as well as in the urine of prostate cancer patients with satisfactory results,demonstrating its enormous potential for predicting prostate cancer disease.展开更多
In this work,one-dimensional(1D)α-MoO_(3)nanobelts and Zr-dopedα-MoO_(3)nanobelts were facilely prepared via a simple hydrothermal method,and the gas sensing performance of the obtained products towards xylene vapor...In this work,one-dimensional(1D)α-MoO_(3)nanobelts and Zr-dopedα-MoO_(3)nanobelts were facilely prepared via a simple hydrothermal method,and the gas sensing performance of the obtained products towards xylene vapor was tested systematically.The characterization results showed that Zr was successfully doped into the lattice of α-MoO_(3)without destroying the unique 1D nanobelt structure and existed as ball-like nanostructures scattered on the nanobelts.The data from the gas sensing test demonstrated that the Zr-doped α-MoO_(3)-based sensor exhibited superior sensing performance with the response towards 100 ppm xylene at the optimum operating temperature of 206℃ reaching 7.99,which was nearly threefold greater compared with that of the pristine α-MoO_(3)-based sensor.Besides,the Zr-doped α-MoO_(3)-based sensor possessed excellent selectivity and a low detection limit.The enhanced sensing performance could be attributed to the 1D nanostructure and the doped Zr.The mechanism of the enhancement of sensing properties induced by the Zr-doping strategy was also demonstrated specifically.展开更多
Herein we successfully synthesized a 3D highly porous NiO film electrode via a simple in situ method,and fabricated an additive-free NiO electrode for battery-type supercapacitor cathodes.The proposed strategy include...Herein we successfully synthesized a 3D highly porous NiO film electrode via a simple in situ method,and fabricated an additive-free NiO electrode for battery-type supercapacitor cathodes.The proposed strategy includes the in situ growth of the precursor film by a hydrothermal method followed by a poremaking step under annealing conditions.The crystallographic properties,morphology and porous structure of the as-made film electrode have been deeply investigated.The results show that the in situ synthesized NiO film possesses integrated advantages of a highly porous inherent structure,high specific surface area,stable framework and enhanced affinity/conductivity with substrates.As for electrochemical investigations,the as-obtained NiO film electrode exhibits enhanced capacity and excellent cycling stability for fast energy storage,and also presents good mechanical flexibility.The assembled asymmetric supercapacitor device exhibits substantially high energy density,and the LED indication test reveales the promising application value of NiO film products.展开更多
Metal-organic frameworks(MOFs),which allow precise control over their porous environment,have attracted extensive research attention in the field of gas adsorption.In this study,an interpenetrating bimetal Cr-based MO...Metal-organic frameworks(MOFs),which allow precise control over their porous environment,have attracted extensive research attention in the field of gas adsorption.In this study,an interpenetrating bimetal Cr-based MOF(termed MIL-126(Cr/Sc))with trigonal-prismatic M_(3)O(M=Cr/Sc,61/39%)secondary building units has been synthesized using a metal metathesis method,and it retains the structure and porosity of the MIL-126(Sc)template and shows by far the highest thermal stability among the Cr-based tricyclic MOFs reported to date.Single component isotherm measurements have revealed that MIL-126(Cr/Sc)displays a higher CO_(2),N_(2)O and C_(2)H_(2) uptake under ambient conditions,and a larger gas uptake at low pressure when compared to pristine MIL-126(Sc).The results of our theoretical calculations indicated that the open Cr(Ⅲ)site had a stronger interaction with gas molecules than an open Sc(Ⅲ)site,thus promoting the gas capture capacity of MIL-126(Cr/Sc).These findings will facilitate further deliberate postsynthetic modifications of MOFs with open metal sites to promote their gas sorption capacity.展开更多
Herein,a BiOCl/Bi_(2)Ti_(2)O_(7)heterojunction was prepared as an efficient visible light-driven photocatalyst through an in situ hydrothermal method,and its photocatalytic properties were investigated via a comparabl...Herein,a BiOCl/Bi_(2)Ti_(2)O_(7)heterojunction was prepared as an efficient visible light-driven photocatalyst through an in situ hydrothermal method,and its photocatalytic properties were investigated via a comparable method.Its structure,morphology and composition were characterized via X-ray diffraction(XRD),field emission scanning electron microscopy(FE-SEM)and X-ray photoelectron spectroscopy(XPS).The formation of a heterojunction between BiOCl and Bi_(2)Ti_(2)O_(7)was also confirmed via transmission electron microscopy(TEM).Moreover,the optical and photocatalytic properties of BiOCl,Bi_(2)Ti_(2)O_(7)and BiOCl/Bi_(2)Ti_(2)O_(7)heterojunction composites with different BiOCl:Bi_(2)Ti_(2)O_(7)mass ratios were investigated.Compared to the case of pure BiOCl,the absorption spectra of the BiOCl/Bi_(2)Ti_(2)O_(7)heterojunction were extended to the visible light region,and the photocatalytic activities were also enhanced.Moreover,the enhancement mechanism of the photocatalytic activity was studied via photocurrent density tests,electrochemical impedance spectroscopy(EIS)and trapping experiments.展开更多
Developing dual functional materials for chlortetracycline hydrochloride(CTC)adsorption and detection is of great importance for wastewater treatment and pollution monitoring.Herein,three novel(Fe-Tb)JLUE-MOGs are syn...Developing dual functional materials for chlortetracycline hydrochloride(CTC)adsorption and detection is of great importance for wastewater treatment and pollution monitoring.Herein,three novel(Fe-Tb)JLUE-MOGs are synthesized through the solvothermal method,and possess hierarchical porous structures,ample active sites and large surface areas.CTC adsorptive removal by the JLUE-MOGs could reach satisfactory results in batch experiments and optimization research due to the joint contributions of pore filling,water affinity,electrostatic interaction,π–πEDA interaction and hydrogen bonding.Additionally,the fluorescence of JLUE-MOG-9 could be turned off by adsorbing CTC due to the inner filter effect(IFE)with a detection limit of 0.079μM by fluorescence spectrometry.More importantly,JLUE-MOG-9@paper are fabricated as portable,handy and cheap detectors for on-site CTC recognition with the help of the corresponding analytical device and a smartphone.The values of the G channel have good linear relationships with the various CTC concentrations regardless of the distilled water,tap water or river water being tested.On the one hand,this study develops efficient and sensitive JLUE-MOGs for CTC removal and detection.On the other hand,the shapeable JLUE-MOG-9@paper detectors and the relevant analytical devices open an avenue for on-site CTC detection by smartphones in real wastewater treatment.展开更多
Due to their environmental friendliness,structural plasticity,and tunable emission,lead-free halide double perovskites offer a broad spectrum of applications in light-emitting diode(LED),photodetectors,infrared imagin...Due to their environmental friendliness,structural plasticity,and tunable emission,lead-free halide double perovskites offer a broad spectrum of applications in light-emitting diode(LED),photodetectors,infrared imaging,and temperature sensing.Herein,we synthesized rare earth-based Cs_(2)NaYCl_(6)double perovskites using a solvothermal method,and Sb^(3+)/Sm^(3+)co-doping can effectively modulate the luminescence by adjusting the band gap structure and channels of energy transfer.With the Sm^(3+)-feeding concentration increasing,the emission could be adjusted from blue to white,attributed to an effective energy transfer from the self-trapped state to Sm^(3+).Temperature-dependent photoluminescence spectra indicate that the double self-trapped exciton emission at low temperatures originated from two minima in the excited state of 3P1.The relative sensitivity of the optical temperature sensor reached 1.08%K^(-1),which was better than that of other rare earth perovskites.The LED device based on Sb^(3+)/Sm^(3+)co-doped Cs_(2)NaYCl_(6)@polymethylmethacrylate displays a chromaticity coordinate of(0.29,0.28),a color rendering index of 87,and the correlated color temperature of 10986 K.Our work explores an in-depth understanding of energy transfer in double self-trapped states and provides new material for advanced applications.展开更多
Crystal structure evolution and temperature-dependent phase transition of solid solutions are much desired for the understanding of the optimization of functional properties.Herein,the NASICON-type NaZr_(2)(PO_(4))_(3...Crystal structure evolution and temperature-dependent phase transition of solid solutions are much desired for the understanding of the optimization of functional properties.Herein,the NASICON-type NaZr_(2)(PO_(4))_(3)–SrZr_(4)(PO_(4))_(6)solid solutions with the formula Na(2−2x)Srx[]xZr_(4)(PO_(4))_(6)(0≤x≤1),where[]represents the vacancy,were prepared by the sol–gel method,and their crystal structures,phase transitions and thermal expansion properties were investigated in detail.In the range of x=0.3–0.35,there is a reversible structural phase transition R3¯c↔R3¯and the different structural models of the R3¯phase and R3¯c phase were built to better understand the phase transition mechanism.We determined the phase transition boundary between the R3¯c and R3¯structures and predicted the phase transition temperature of Na_((2−2x))Srx[]_(x)Zr_(4)(PO_(4))_(6)with any x for further investigation of controlled physical properties.The results indicated that Na_(0.5)Sr_(0.75)[]_(0.75)Zr_(4)(PO_(4))_(6)showed a near zero thermal expansion in the temperature range of 450–600 K,which can find potential applications.展开更多
As nonlinear optical(NLO)materials,phosphates often suffer from weak second harmonic generation(SHG)response and low birefringence.Here,we report the successful synthesis of a new UV NLO ortho-phosphate,β-Li_(2)RbBi(...As nonlinear optical(NLO)materials,phosphates often suffer from weak second harmonic generation(SHG)response and low birefringence.Here,we report the successful synthesis of a new UV NLO ortho-phosphate,β-Li_(2)RbBi(PO_(4))_(2),by the high temperature solution method,and demonstrate that it crystallizes in a polar space group of P2_(1)and is composed of 1D 1[Bi_(4)(PO_(4))_(8)]_(∞)infinite chains that are constructed from 1[Bi_(2)O_(11)]_(∞)chains and[PO_(4)]clusters.The optical functional motifs 1[Bi_(4)(PO_(4))_(8)]_(∞)are arranged in a parallel mode,which greatly improves the polarizability of the phosphate.As a result,β-Li_(2)RbBi(PO_(4))_(2)pre-sents the largest SHG response,5.2×KH_(2)PO_(4)(KDP),at 1064 nm incident radiation among all the Bi-based phosphates.Furthermore,first-principles calculations reveal that the synergistic effect of P-O and Bi-O groups contributes significantly to the optical properties of the title compound.展开更多
The development of new stimuli-responsive materials with controllable properties has been highly desirable in the past decade owing to their increasing application demand in various areas.In this work,two tripyridyl-t...The development of new stimuli-responsive materials with controllable properties has been highly desirable in the past decade owing to their increasing application demand in various areas.In this work,two tripyridyl-triazine-based zinc bromide complexes,[ZnBr_(2)(2-TPT)](1)and[ZnBr_(2)(2-TPT)]·C_(6)H_(5)CH_(2)OH(2)(2-TPT=2,4,6-tri(2-pyridyl)-1,3,5-triazine),have been prepared through the solvent evaporation method,and exhibit lattice solvent controlled photochromic performance in the crystalline state as well as solvent-induced photochromism in the solution state.Furthermore,the two complexes display tunable photochromic and photoluminescence properties in the crystalline state through the reversible desorption-adsorption of lattice benzyl alcohol molecules.Crystalline 1 and 2 are very sensitive to triple photostimulation(sunlight,ultraviolet light and X-ray irradiation)and exhibit excellent photochromic behaviors with distinct coloration contrast(light blue for 1vs.deep blue for 2),which is ascribed to different supramolecular frameworks via weak interactions(lone pair-πandπ⋯πinteractions).Meanwhile,crystalline 1 and 2 also exhibit completely different quenching efficiency during the coloration-decoloration processes,which is a typical example of a photo-stimuli dual-output responsive system and could be potentially applied in optical switches.The photochromic mechanism of photoinduced intermolecular electron transfer(PIET)has been carefully verified by the combination of experimental and theoretical investigations.展开更多
Benzene and formaldehyde are representatives of volatile organic compounds(VOCs),which are harmful to human beings due to their highly toxic and carcinogenic nature.So exploring efficient gas sensing materials to dete...Benzene and formaldehyde are representatives of volatile organic compounds(VOCs),which are harmful to human beings due to their highly toxic and carcinogenic nature.So exploring efficient gas sensing materials to detect ultra-low concentration benzene is of utmost significance.In this paper,an organic-inorganic layered perovskite(C_(4)H_(9)NH_(3))_(2)PbI_(2)Br_(2)was synthesized through a facile solution method.And it was employed as a resistive gas sensing candidate to benzene,exhibiting ultrahigh response,fast response-recovery,good selectivity and repeatability for parts per trillion(ppt)level benzene detection at the optimum operation temperature(OOT)of 160°C,with a response of 90.7 for 1 ppt benzene.In situ infrared analysis confirmed that the gas sensing mechanism is originated from the physical adsorption-desorption of benzene molecules onto the(C_(4)H_(9)NH_(3))_(2)PbI_(2)Br_(2)surface,the charge transfer model of which is different from that of conventional metal oxides.A promising application using such organic-inorganic hybrid perovskites for monitoring ultra-low concentration benzene might be interesting to researchers in the gas sensor field.展开更多
The dynamical effects of a cylindrically symmetric moving shock wave in a self-gravitating and rotating ideal gas medium influenced by a magnetic field and radiation heat flux are investigated.The dynamics of the shoc...The dynamical effects of a cylindrically symmetric moving shock wave in a self-gravitating and rotating ideal gas medium influenced by a magnetic field and radiation heat flux are investigated.The dynamics of the shock wave are governed by the one-dimensional motion of the gas,and the energy equation contains the effect of thermal radiation in the setting of an optically thick limit.A mathematical model is established using the Lie symmetry method,and all possible cases of similarity solutions are obtained by choosing different subalgebras from the optimal system.The numerical computations are performed using a fourth-order Runge-Kutta method.For a power law shock path,the contour plots of flow variables such as density and velocity are presented for convenient visualization.The variations of the shock strength and the flow variables in the physical flow field region behind the shock front with changes in the values of the gravitational parameter,rotational parameter,adiabatic index,ambient magnetic field strength,similarity exponent,and radiative heat transfer parameter are investigated.It is found that increases in the ambient magnetic field strength and the radiative heat transfer parameter lead to decay of the shock wave.For a power law shock path,it is found that increases in the gravitational parameter and adiabatic index cause decay of the shock wave,whereas for an exponential law shock path,the shock strength is increased by increases in the values of these parameters.展开更多
基金Supported by an open research project of the Capital Institute of Health Management and Policy(2023JD05).
文摘Introduction:To construct a set of evaluation indicators suitable for the public health system in primary and secondary schools in Beijing,this study aimed to provide a basis for objectively assessing the current status of system development and identifying future directions for improvement.Methods:An indicator pool was established based on literature reviews and expert consultation.The indicator system was then refined and finalized through two rounds of the Delphi method,and the weights of the indicators were determined using the analytic hierarchy process.Results:The expert participation rate reached 100%,and the average expert authority coefficient was 0.87.The indicator coordination coefficient W was statistically significant(P<0.001).Ultimately,an evaluation system comprising 5 first-level indicators,15 second-level indicators,and 39 third-level indicators was developed.Conclusion:The indicator system constructed in this study shows good expert consistency and credibility.It can effectively pinpoint key components of system development,providing a scientific foundation for optimizing resource allocation and supporting ongoing improvement.
基金supported by the National Natural Science Foundation of China(22175175,22193043)the Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR118)+1 种基金the Natural Science Foundation of Fujian Province(2022L3092)the Youth Innovation Promotion Association CAS(2022303).
文摘Transition-metal-based chalcogenides have recently emerged as greatly promising infrared nonlinear optical(IR-NLO)candidates due to their unique structural chemistries and rich optical properties.However,Fe-based IR-NLO chalcogenides with phase-matching(PM)features have not yet been reported.In this work,a new non-centrosymmetric(NCS)melilite oxychalcogenide,Sr_(2)FeGe_(2)OS_(6),has been prepared by an isomorphous substitution method,and the relationships between the microscopic crystal structure and macroscopic NLO activity were systematically investigated.Sr_(2)FeGe_(2)OS_(6) adopts the tetragonal space group of P421m(no.113)and features a unique two-dimensional structure with Cairo pentagonal tiling layers formed by the alternating connection of[Ge_(2)OS_(6)]dimers and[FeS_(4)]tetrahedra via corner-sharing and with the charge-balanced Sr^(2+)cations between these layers.Excitingly,Sr_(2)FeGe_(2)OS_(6) is the first Fe-based example capable of achieving PM in the IR-NLO chalcogenide system and displays an outstanding IR-NLO comprehensive performance,including a wide energy gap(E_(g)=2.24 eV),sufficient second-harmonic-generation(SHG)efficiency(d_(eff)=5.89 pm V^(-1) at 2050 nm)and strong laser-induced damage threshold(LIDT=14.42 MW cm^(-2)).Deeper structural and theoretical analysis suggests that the ordered arrangement of NLO-active motifs,[Ge_(2)OS_(6)]dimers and[FeS_(4)]tetrahedra,makes significant contributions to the strong d_(eff) and large birefringence(Δn).This work not only demonstrates a PM Fe-based NCS material for the first time but also puts forward a new design avenue for high-performance IR-NLO materials.
基金supported by the National Natural Science Foundation of China(No.22374058,21775052)the Open Funds of the State Key Laboratory of Electroanalytical Chemistry,China(No.SKLEAC202201).
文摘Herein,a highly sensitive detection platform for the dual-mode determination of sarcosine by fluorescence and colorimetry was constructed based on zirconium-based metal organic frameworks(Zr-MOFs)with multi-enzyme immobilization.Zr-MOFs with peroxidase-mimicking activity were firstly prepared by a solvothermal method,and sarcosine oxidase(SOX)and horseradish peroxidase(HRP)were simultaneously encapsulated in the Zr-MOFs to form the Zr-MOFs@SOX@HRP composite.Oxidation of sarcosine could be catalyzed by the SOX in the Zr-MOFs@SOX@HRP composite to generate hydrogen peroxide(H_(2)O_(2)).The generated H_(2)O_(2)was decomposed through the synergistic catalysis by Zr-MOFs and HRP to generate free radicals that could oxidize the chromogenic substrate p-phenylenediamine(PPD)to produce oxPPD.The oxPPD generated could quench the fluorescence of carbon dots at 510 nm via the internal filtering effect(IFE).The amount of sarcosine could be sensitively detected by monitoring the changes of the colorimetric and fluorescence signals,with detection limits of 0.44μM and 0.21μM,respectively.Thus,the dual-mode detection of sarcosine by fluorescence and colorimetry through a Zr-MOF-mediated cascade reaction system was realized.The method was applied to the determination of sarcosine in the urine of healthy individuals as well as in the urine of prostate cancer patients with satisfactory results,demonstrating its enormous potential for predicting prostate cancer disease.
基金National Natural Science Foundation of China(Grant No.61874048,11874348,U1831113,61974055)Project of Science and Technology Plan of Jilin Province(Grant No.20180414020GH)for the support to this work.
文摘In this work,one-dimensional(1D)α-MoO_(3)nanobelts and Zr-dopedα-MoO_(3)nanobelts were facilely prepared via a simple hydrothermal method,and the gas sensing performance of the obtained products towards xylene vapor was tested systematically.The characterization results showed that Zr was successfully doped into the lattice of α-MoO_(3)without destroying the unique 1D nanobelt structure and existed as ball-like nanostructures scattered on the nanobelts.The data from the gas sensing test demonstrated that the Zr-doped α-MoO_(3)-based sensor exhibited superior sensing performance with the response towards 100 ppm xylene at the optimum operating temperature of 206℃ reaching 7.99,which was nearly threefold greater compared with that of the pristine α-MoO_(3)-based sensor.Besides,the Zr-doped α-MoO_(3)-based sensor possessed excellent selectivity and a low detection limit.The enhanced sensing performance could be attributed to the 1D nanostructure and the doped Zr.The mechanism of the enhancement of sensing properties induced by the Zr-doping strategy was also demonstrated specifically.
基金supported by the Natural Science Foundation of Hebei Province(No.B2015203350 and B2019203487)the National Science Foundation of China(No.21403187 and 21875206)+1 种基金the China Postdoctoral Science Foundation(No.2015M581314 and 2015T80229)the Research Foundation of Yanshan University(No.14LGA016 and B772).
文摘Herein we successfully synthesized a 3D highly porous NiO film electrode via a simple in situ method,and fabricated an additive-free NiO electrode for battery-type supercapacitor cathodes.The proposed strategy includes the in situ growth of the precursor film by a hydrothermal method followed by a poremaking step under annealing conditions.The crystallographic properties,morphology and porous structure of the as-made film electrode have been deeply investigated.The results show that the in situ synthesized NiO film possesses integrated advantages of a highly porous inherent structure,high specific surface area,stable framework and enhanced affinity/conductivity with substrates.As for electrochemical investigations,the as-obtained NiO film electrode exhibits enhanced capacity and excellent cycling stability for fast energy storage,and also presents good mechanical flexibility.The assembled asymmetric supercapacitor device exhibits substantially high energy density,and the LED indication test reveales the promising application value of NiO film products.
基金the National Natural Science Foundation of China(No.21908153,U20B6004 and 22090062)the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering[2021SX-TD003].
文摘Metal-organic frameworks(MOFs),which allow precise control over their porous environment,have attracted extensive research attention in the field of gas adsorption.In this study,an interpenetrating bimetal Cr-based MOF(termed MIL-126(Cr/Sc))with trigonal-prismatic M_(3)O(M=Cr/Sc,61/39%)secondary building units has been synthesized using a metal metathesis method,and it retains the structure and porosity of the MIL-126(Sc)template and shows by far the highest thermal stability among the Cr-based tricyclic MOFs reported to date.Single component isotherm measurements have revealed that MIL-126(Cr/Sc)displays a higher CO_(2),N_(2)O and C_(2)H_(2) uptake under ambient conditions,and a larger gas uptake at low pressure when compared to pristine MIL-126(Sc).The results of our theoretical calculations indicated that the open Cr(Ⅲ)site had a stronger interaction with gas molecules than an open Sc(Ⅲ)site,thus promoting the gas capture capacity of MIL-126(Cr/Sc).These findings will facilitate further deliberate postsynthetic modifications of MOFs with open metal sites to promote their gas sorption capacity.
基金National Natural Science Foundation of China(No.51672215,11274251)Research Fund for the Doctoral Program of Higher Education of China(RFDP)(No.20136101110017)+2 种基金Natural Science Foundation of Shaanxi Province(No.2014JM1004)Graduate independent innovation project(No.YZZ17098)Excellent doctoral dissertation training project(No.YYB17004)。
文摘Herein,a BiOCl/Bi_(2)Ti_(2)O_(7)heterojunction was prepared as an efficient visible light-driven photocatalyst through an in situ hydrothermal method,and its photocatalytic properties were investigated via a comparable method.Its structure,morphology and composition were characterized via X-ray diffraction(XRD),field emission scanning electron microscopy(FE-SEM)and X-ray photoelectron spectroscopy(XPS).The formation of a heterojunction between BiOCl and Bi_(2)Ti_(2)O_(7)was also confirmed via transmission electron microscopy(TEM).Moreover,the optical and photocatalytic properties of BiOCl,Bi_(2)Ti_(2)O_(7)and BiOCl/Bi_(2)Ti_(2)O_(7)heterojunction composites with different BiOCl:Bi_(2)Ti_(2)O_(7)mass ratios were investigated.Compared to the case of pure BiOCl,the absorption spectra of the BiOCl/Bi_(2)Ti_(2)O_(7)heterojunction were extended to the visible light region,and the photocatalytic activities were also enhanced.Moreover,the enhancement mechanism of the photocatalytic activity was studied via photocurrent density tests,electrochemical impedance spectroscopy(EIS)and trapping experiments.
基金supported by the Natural Science Foundation from the Department of Science&Technology of Jilin Province of China(Project No.20210101383JC)Major Project of Jilin Province Department of Science and Technology(Project No.20200503003SF)+3 种基金Natural Science Foundation of Chongqing of China(Project No.cstc2021jcyj-msxmX1029)Technology Plan Project of Jilin Province Department(Project No.20200403007SF)the 111 Project(Project No.B16020)Graduate Innovation Fund of Jilin University(Project No.419100201159).
文摘Developing dual functional materials for chlortetracycline hydrochloride(CTC)adsorption and detection is of great importance for wastewater treatment and pollution monitoring.Herein,three novel(Fe-Tb)JLUE-MOGs are synthesized through the solvothermal method,and possess hierarchical porous structures,ample active sites and large surface areas.CTC adsorptive removal by the JLUE-MOGs could reach satisfactory results in batch experiments and optimization research due to the joint contributions of pore filling,water affinity,electrostatic interaction,π–πEDA interaction and hydrogen bonding.Additionally,the fluorescence of JLUE-MOG-9 could be turned off by adsorbing CTC due to the inner filter effect(IFE)with a detection limit of 0.079μM by fluorescence spectrometry.More importantly,JLUE-MOG-9@paper are fabricated as portable,handy and cheap detectors for on-site CTC recognition with the help of the corresponding analytical device and a smartphone.The values of the G channel have good linear relationships with the various CTC concentrations regardless of the distilled water,tap water or river water being tested.On the one hand,this study develops efficient and sensitive JLUE-MOGs for CTC removal and detection.On the other hand,the shapeable JLUE-MOG-9@paper detectors and the relevant analytical devices open an avenue for on-site CTC detection by smartphones in real wastewater treatment.
基金supported by the National Natural Science Foundation of China(Grant No.52162021 and 22175043)Open Foundation of State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures(Grant No.MMCS2023OF05)Guangxi Science and Technology Plan Project(Guike AA23073018).
文摘Due to their environmental friendliness,structural plasticity,and tunable emission,lead-free halide double perovskites offer a broad spectrum of applications in light-emitting diode(LED),photodetectors,infrared imaging,and temperature sensing.Herein,we synthesized rare earth-based Cs_(2)NaYCl_(6)double perovskites using a solvothermal method,and Sb^(3+)/Sm^(3+)co-doping can effectively modulate the luminescence by adjusting the band gap structure and channels of energy transfer.With the Sm^(3+)-feeding concentration increasing,the emission could be adjusted from blue to white,attributed to an effective energy transfer from the self-trapped state to Sm^(3+).Temperature-dependent photoluminescence spectra indicate that the double self-trapped exciton emission at low temperatures originated from two minima in the excited state of 3P1.The relative sensitivity of the optical temperature sensor reached 1.08%K^(-1),which was better than that of other rare earth perovskites.The LED device based on Sb^(3+)/Sm^(3+)co-doped Cs_(2)NaYCl_(6)@polymethylmethacrylate displays a chromaticity coordinate of(0.29,0.28),a color rendering index of 87,and the correlated color temperature of 10986 K.Our work explores an in-depth understanding of energy transfer in double self-trapped states and provides new material for advanced applications.
基金supported by the National Natural Science Foundation of China(Grants 91622125,51722202 and 51572023)the Natural Science Foundations of Beijing(2172036)support of the Russian Foundation for Basic Research(17-52-53031).
文摘Crystal structure evolution and temperature-dependent phase transition of solid solutions are much desired for the understanding of the optimization of functional properties.Herein,the NASICON-type NaZr_(2)(PO_(4))_(3)–SrZr_(4)(PO_(4))_(6)solid solutions with the formula Na(2−2x)Srx[]xZr_(4)(PO_(4))_(6)(0≤x≤1),where[]represents the vacancy,were prepared by the sol–gel method,and their crystal structures,phase transitions and thermal expansion properties were investigated in detail.In the range of x=0.3–0.35,there is a reversible structural phase transition R3¯c↔R3¯and the different structural models of the R3¯phase and R3¯c phase were built to better understand the phase transition mechanism.We determined the phase transition boundary between the R3¯c and R3¯structures and predicted the phase transition temperature of Na_((2−2x))Srx[]_(x)Zr_(4)(PO_(4))_(6)with any x for further investigation of controlled physical properties.The results indicated that Na_(0.5)Sr_(0.75)[]_(0.75)Zr_(4)(PO_(4))_(6)showed a near zero thermal expansion in the temperature range of 450–600 K,which can find potential applications.
基金supported by the National Natural Science Foundation of China(51962033)the Tianshan Talent Project of Xinjiang Uygur Autonomous Region of China(2022TSYCJU0004)the Xinjiang Major Science and Technology Project(2021A01001-3).
文摘As nonlinear optical(NLO)materials,phosphates often suffer from weak second harmonic generation(SHG)response and low birefringence.Here,we report the successful synthesis of a new UV NLO ortho-phosphate,β-Li_(2)RbBi(PO_(4))_(2),by the high temperature solution method,and demonstrate that it crystallizes in a polar space group of P2_(1)and is composed of 1D 1[Bi_(4)(PO_(4))_(8)]_(∞)infinite chains that are constructed from 1[Bi_(2)O_(11)]_(∞)chains and[PO_(4)]clusters.The optical functional motifs 1[Bi_(4)(PO_(4))_(8)]_(∞)are arranged in a parallel mode,which greatly improves the polarizability of the phosphate.As a result,β-Li_(2)RbBi(PO_(4))_(2)pre-sents the largest SHG response,5.2×KH_(2)PO_(4)(KDP),at 1064 nm incident radiation among all the Bi-based phosphates.Furthermore,first-principles calculations reveal that the synergistic effect of P-O and Bi-O groups contributes significantly to the optical properties of the title compound.
基金National Natural Science Foundation of China(NSFC-21171110)Natural Science Foundation of Science and Technology Agency of Shanxi Province(201901D111275)+1 种基金Transformation of Scientific and Technological Achievements Programs of Higher Education Institutions in Shanxi(2020CG032)1331 Project of Shanxi Province.
文摘The development of new stimuli-responsive materials with controllable properties has been highly desirable in the past decade owing to their increasing application demand in various areas.In this work,two tripyridyl-triazine-based zinc bromide complexes,[ZnBr_(2)(2-TPT)](1)and[ZnBr_(2)(2-TPT)]·C_(6)H_(5)CH_(2)OH(2)(2-TPT=2,4,6-tri(2-pyridyl)-1,3,5-triazine),have been prepared through the solvent evaporation method,and exhibit lattice solvent controlled photochromic performance in the crystalline state as well as solvent-induced photochromism in the solution state.Furthermore,the two complexes display tunable photochromic and photoluminescence properties in the crystalline state through the reversible desorption-adsorption of lattice benzyl alcohol molecules.Crystalline 1 and 2 are very sensitive to triple photostimulation(sunlight,ultraviolet light and X-ray irradiation)and exhibit excellent photochromic behaviors with distinct coloration contrast(light blue for 1vs.deep blue for 2),which is ascribed to different supramolecular frameworks via weak interactions(lone pair-πandπ⋯πinteractions).Meanwhile,crystalline 1 and 2 also exhibit completely different quenching efficiency during the coloration-decoloration processes,which is a typical example of a photo-stimuli dual-output responsive system and could be potentially applied in optical switches.The photochromic mechanism of photoinduced intermolecular electron transfer(PIET)has been carefully verified by the combination of experimental and theoretical investigations.
基金National Natural Science Foundation of China(NSFC Grant No.21401139 and No.21271139)Tianjin Natural Science Council(Grant No.15JCQNJC02900)111 Project(B12015)。
文摘Benzene and formaldehyde are representatives of volatile organic compounds(VOCs),which are harmful to human beings due to their highly toxic and carcinogenic nature.So exploring efficient gas sensing materials to detect ultra-low concentration benzene is of utmost significance.In this paper,an organic-inorganic layered perovskite(C_(4)H_(9)NH_(3))_(2)PbI_(2)Br_(2)was synthesized through a facile solution method.And it was employed as a resistive gas sensing candidate to benzene,exhibiting ultrahigh response,fast response-recovery,good selectivity and repeatability for parts per trillion(ppt)level benzene detection at the optimum operation temperature(OOT)of 160°C,with a response of 90.7 for 1 ppt benzene.In situ infrared analysis confirmed that the gas sensing mechanism is originated from the physical adsorption-desorption of benzene molecules onto the(C_(4)H_(9)NH_(3))_(2)PbI_(2)Br_(2)surface,the charge transfer model of which is different from that of conventional metal oxides.A promising application using such organic-inorganic hybrid perovskites for monitoring ultra-low concentration benzene might be interesting to researchers in the gas sensor field.
文摘The dynamical effects of a cylindrically symmetric moving shock wave in a self-gravitating and rotating ideal gas medium influenced by a magnetic field and radiation heat flux are investigated.The dynamics of the shock wave are governed by the one-dimensional motion of the gas,and the energy equation contains the effect of thermal radiation in the setting of an optically thick limit.A mathematical model is established using the Lie symmetry method,and all possible cases of similarity solutions are obtained by choosing different subalgebras from the optimal system.The numerical computations are performed using a fourth-order Runge-Kutta method.For a power law shock path,the contour plots of flow variables such as density and velocity are presented for convenient visualization.The variations of the shock strength and the flow variables in the physical flow field region behind the shock front with changes in the values of the gravitational parameter,rotational parameter,adiabatic index,ambient magnetic field strength,similarity exponent,and radiative heat transfer parameter are investigated.It is found that increases in the ambient magnetic field strength and the radiative heat transfer parameter lead to decay of the shock wave.For a power law shock path,it is found that increases in the gravitational parameter and adiabatic index cause decay of the shock wave,whereas for an exponential law shock path,the shock strength is increased by increases in the values of these parameters.
