The synthetic making test has been widely used in evaluating the break ability of high-voltage circuit breaker. However, the test research and application are still inadequate, especially in the condition of rated vol...The synthetic making test has been widely used in evaluating the break ability of high-voltage circuit breaker. However, the test research and application are still inadequate, especially in the condition of rated voltage. According to the realistic conditions of test stations in China, a control device based on pre-arcing current detection and phase control is proposed in this paper. A sample of the control device made up of DSP TMS320LF2407A is fabricated, in which the CPLD MAX7064 is used to transmit signals for EMC design. It can be applied in full voltage synthetic making test at a level of 126kV/63kA. The test results show that, it is accurate to control the making phase of the applied voltage, whether the closing is demanded at voltage peak or zero.展开更多
It is challenging to cooperatively improve the nonlinear optical(NLO)efficiency and the laser-induced damage threshold(LIDT).This work reports a novel IR NLO materials CsInP_(2)S_(7)(CIPS)designed by combination the s...It is challenging to cooperatively improve the nonlinear optical(NLO)efficiency and the laser-induced damage threshold(LIDT).This work reports a novel IR NLO materials CsInP_(2)S_(7)(CIPS)designed by combination the strategies of alkali metals substitution and microscopic NLO units PS4 introduction based on AgGaS_(2).CIPS was composed of strongly distorted[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers constructed by corner-sharing[PS_(4)]^(3-),which increase the NLO efficiency and decrease thermal expansion anisotropy simultaneously.Compared with AgGaS_(2),CIPS exhibited strong phase matchable NLO response ca.1.1×AGS@2.1μm,high LIDT ca.20.8×AgGaS_(2),and IR transparency up to 15.3μm.Structural analysis and theoretical investigation confirmed that large SHG effect and ultrahigh LIDT of CIPS originated from the synergistic contribution of[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers.These results indicate that CIPS is a promising NLO candidate in the mid-IR region,and this study provides a new approach for developing potential NLO-LIDT compatible materials.展开更多
Air pollution is a major obstacle to future sustainability,and traffic pollution has become a large drag on the sustainable developments of future metropolises.Here,combined with the large volume of real-time monitori...Air pollution is a major obstacle to future sustainability,and traffic pollution has become a large drag on the sustainable developments of future metropolises.Here,combined with the large volume of real-time monitoring data,we propose a deep learning model,iDeepAir,to predict surface-level PM2.5 concentration in Shanghai megacity and link with MEIC emission inventory creatively to decipher urban traffic impacts on air quality.Our model exhibits high-fidelity in reproducing pollutant concentrations and reduces the MAE from 25.355μg/m^(3) to 12.283μg/m^(3) compared with other models.And identifies the ranking of major factors,local meteorological conditions have become a nonnegligible factor.Layer-wise relevance propagation(LRP)is used here to enhance the interpretability of the model and we visualize and analyze the reasons for the different correlation between traffic density and PM_(2.5) concentration in various regions of Shanghai.Meanwhile,As the strict and effective industrial emission reduction measurements implementing in China,the contribution of urban traffic to PM_(2.5) formation calculated by combining MEIC emission inventory and LRP is gradually increasing from 18.03%in 2011 to 24.37% in 2017 in Shanghai,and the impact of traffic emissions would be ever-prominent in 2030 according to our prediction.We also infer that the promotion of vehicular electrification would achieve further alleviation of PM_(2.5) about 8.45% by 2030 gradually.These insights are of great significance to provide the decision-making basis for accurate and high-efficient traffic management and urban pollution control,and eventually benefit people’s lives and high-quality sustainable developments of cities.展开更多
Two-dimensional(2D)materials with reversible phase transformation are appealing for their rich physics and potential applications in information storage.However,up to now,reversible phase transitions in 2D materials t...Two-dimensional(2D)materials with reversible phase transformation are appealing for their rich physics and potential applications in information storage.However,up to now,reversible phase transitions in 2D materials that can be driven by facile nondestructive methods,such as temperature,are still rare.Here,we introduce ultrathin Cu_(9)S_(5)crystals grown by chemical vapor deposition(CVD)as an exemplary case.For the first time,their basic electrical properties were investigated based on Hall measurements,showing a record high hole carrier density of~1022 cm^(-3) among 2D semiconductors.Besides,an unusual and repeatable conductivity switching behavior at~250 K were readily observed in a wide thickness range of CVD-grown Cu_(9)S_(5)(down to 2 unit-cells).Confirmed by in-situ selected area electron diffraction,this unusual behavior can be ascribed to the reversible structural phase transition between the room-temperature hexagonalβphase and low-temperatureβ’phase with a superstructure.Our work provides new insights to understand the physical properties of ultrathin Cu_(9)S_(5)crystals,and brings new blood to the 2D materials family with reversible phase transitions.展开更多
This study reports an efficient method for growing high-quality boron nitride nanotubes(BNNTs)via chemical vapor deposition of low-melting-point precursors—magnesium diboride(MgB_(2)),magnesium nitride(Mg_(3)N_(2)),a...This study reports an efficient method for growing high-quality boron nitride nanotubes(BNNTs)via chemical vapor deposition of low-melting-point precursors—magnesium diboride(MgB_(2)),magnesium nitride(Mg_(3)N_(2)),and diboron trioxide(B_(2)O)at a growth temperature of 1000–1300℃.The strong oxygen-capturing ability of Mg_(3)N_(2)inhibits the formation of high-melting-point Mg_(3)B_(2)O_(6),which helps MgB_(2)to maintain an efficient and stable catalytic capacity,thereby enhancing its growth efficiency and utilization of the boron source.Moreover,polydimethylsiloxane(PDMS)composites formed from these BNNTs demonstrated much greater thermal conductivities than pure PDMS.Thus,this novel strategy for preparing BNNTs is efficient,and they have great potential for application as thermal interface materials.展开更多
Near-infrared(NIR)-II light-excitable photonic agents capable of generating tumor hyperthermia and cytotoxic free radicals are promising for synergistic phototherapy of tumors.However,the lack of NIR-II excitable agen...Near-infrared(NIR)-II light-excitable photonic agents capable of generating tumor hyperthermia and cytotoxic free radicals are promising for synergistic phototherapy of tumors.However,the lack of NIR-II excitable agents makes it challenging to achieve combinational tumor phototherapy.Here,the authors have reported on a tumor-targeting and degradable hybrid copper sulfide(CuS)nanoparticle(AIBA@CuS-FA)via loading a hydrophilic Azo initiator(AIBA)into an amphiphilic lipid-encapsulating CuS nanoparticle.AIBA@CuS-FA shows high photothermal conversion efficiency(PCE≈47.5%)at 1064 nm,enabling heat production to trigger tumor hyperthermia and thermal decomposition of AIBA into cytotoxic free alkyl radicals upon irradiation with a 1064-nm laser under low-power density(0.5 W/cm2).Moreover,alkyl radicals can drive degradation of AIBA@CuS-FA and embedded CuS nanodisks,releasing Cu^(2+)ions that can catalyze a Fenton-like reaction for hydroxyl radical(•OH)production to promote tumor therapy.Findings demonstrate promise for combinational photothermal therapy(PTT),oxygen-independent alkyl radical therapy,and chemodynamic therapy(CDT)of tumors.展开更多
Symmetry breaking of metal cluster-based strongly correlated systems can give rise to collective phenomena.Here,the twodimensional Nb_(3) cluster compound Nb_(3)Cl_(8) is shown to suffer dramatic symmetry breaking and...Symmetry breaking of metal cluster-based strongly correlated systems can give rise to collective phenomena.Here,the twodimensional Nb_(3) cluster compound Nb_(3)Cl_(8) is shown to suffer dramatic symmetry breaking and electron disproportionation under compression.A structural phase transition from trigonal P–3m1 to monoclinic C2/m is observed near 8 GPa with the three-fold symmetry breaking.Electron disproportionation occurs on Nb_(3) clusters from delocalized Nb^(8/3+)Nb^(8/3+)Nb^(8/3+)to localized Nb^(3+)Nb^(3+)Nb^(2+),which results in a subtle bandgap discontinuity,as evidenced by electrical transport and UV-Vis absorption measurements.展开更多
文摘The synthetic making test has been widely used in evaluating the break ability of high-voltage circuit breaker. However, the test research and application are still inadequate, especially in the condition of rated voltage. According to the realistic conditions of test stations in China, a control device based on pre-arcing current detection and phase control is proposed in this paper. A sample of the control device made up of DSP TMS320LF2407A is fabricated, in which the CPLD MAX7064 is used to transmit signals for EMC design. It can be applied in full voltage synthetic making test at a level of 126kV/63kA. The test results show that, it is accurate to control the making phase of the applied voltage, whether the closing is demanded at voltage peak or zero.
基金the Natural Science Foundation of China(No.22105218).
文摘It is challenging to cooperatively improve the nonlinear optical(NLO)efficiency and the laser-induced damage threshold(LIDT).This work reports a novel IR NLO materials CsInP_(2)S_(7)(CIPS)designed by combination the strategies of alkali metals substitution and microscopic NLO units PS4 introduction based on AgGaS_(2).CIPS was composed of strongly distorted[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers constructed by corner-sharing[PS_(4)]^(3-),which increase the NLO efficiency and decrease thermal expansion anisotropy simultaneously.Compared with AgGaS_(2),CIPS exhibited strong phase matchable NLO response ca.1.1×AGS@2.1μm,high LIDT ca.20.8×AgGaS_(2),and IR transparency up to 15.3μm.Structural analysis and theoretical investigation confirmed that large SHG effect and ultrahigh LIDT of CIPS originated from the synergistic contribution of[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers.These results indicate that CIPS is a promising NLO candidate in the mid-IR region,and this study provides a new approach for developing potential NLO-LIDT compatible materials.
基金supported by the Anhui Science Foundation for Distinguished Young Scholars (No.1908085J24)the Natural Science Foundation of China (No.62072427)the Jiangsu Natural Science Foundation (No. BK20191193)
文摘Air pollution is a major obstacle to future sustainability,and traffic pollution has become a large drag on the sustainable developments of future metropolises.Here,combined with the large volume of real-time monitoring data,we propose a deep learning model,iDeepAir,to predict surface-level PM2.5 concentration in Shanghai megacity and link with MEIC emission inventory creatively to decipher urban traffic impacts on air quality.Our model exhibits high-fidelity in reproducing pollutant concentrations and reduces the MAE from 25.355μg/m^(3) to 12.283μg/m^(3) compared with other models.And identifies the ranking of major factors,local meteorological conditions have become a nonnegligible factor.Layer-wise relevance propagation(LRP)is used here to enhance the interpretability of the model and we visualize and analyze the reasons for the different correlation between traffic density and PM_(2.5) concentration in various regions of Shanghai.Meanwhile,As the strict and effective industrial emission reduction measurements implementing in China,the contribution of urban traffic to PM_(2.5) formation calculated by combining MEIC emission inventory and LRP is gradually increasing from 18.03%in 2011 to 24.37% in 2017 in Shanghai,and the impact of traffic emissions would be ever-prominent in 2030 according to our prediction.We also infer that the promotion of vehicular electrification would achieve further alleviation of PM_(2.5) about 8.45% by 2030 gradually.These insights are of great significance to provide the decision-making basis for accurate and high-efficient traffic management and urban pollution control,and eventually benefit people’s lives and high-quality sustainable developments of cities.
基金J.X.W.acknowledges financial support from the National Natural Science Foundation of China(NSFC)(No.92064005)Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure(No.SKL202211SIC)+6 种基金H.T.Y.acknowledges the support from the NSFC(Nos.51861145201,52072168,and 21733001)the National Key Research and Development Program of China(No.2018YFA0306200)J.W.H.acknowledges the support from the National Key Research and Development Program of China(No.2021YFA1202901)X.W.F.acknowledges financial support from the NSFC at grant(Nos.11974191 and 2217830)the National Key Research and Development Program of China at grant(No.2020YFA0309300)the Natural Science Foundation of Tianjin at grant(Nos.20JCZDJC00560 and 20JCJQJC00210)the 111 Project(No.B23045).
文摘Two-dimensional(2D)materials with reversible phase transformation are appealing for their rich physics and potential applications in information storage.However,up to now,reversible phase transitions in 2D materials that can be driven by facile nondestructive methods,such as temperature,are still rare.Here,we introduce ultrathin Cu_(9)S_(5)crystals grown by chemical vapor deposition(CVD)as an exemplary case.For the first time,their basic electrical properties were investigated based on Hall measurements,showing a record high hole carrier density of~1022 cm^(-3) among 2D semiconductors.Besides,an unusual and repeatable conductivity switching behavior at~250 K were readily observed in a wide thickness range of CVD-grown Cu_(9)S_(5)(down to 2 unit-cells).Confirmed by in-situ selected area electron diffraction,this unusual behavior can be ascribed to the reversible structural phase transition between the room-temperature hexagonalβphase and low-temperatureβ’phase with a superstructure.Our work provides new insights to understand the physical properties of ultrathin Cu_(9)S_(5)crystals,and brings new blood to the 2D materials family with reversible phase transitions.
基金supported by the National Natural Science Foundation of China(No.51972162).
文摘This study reports an efficient method for growing high-quality boron nitride nanotubes(BNNTs)via chemical vapor deposition of low-melting-point precursors—magnesium diboride(MgB_(2)),magnesium nitride(Mg_(3)N_(2)),and diboron trioxide(B_(2)O)at a growth temperature of 1000–1300℃.The strong oxygen-capturing ability of Mg_(3)N_(2)inhibits the formation of high-melting-point Mg_(3)B_(2)O_(6),which helps MgB_(2)to maintain an efficient and stable catalytic capacity,thereby enhancing its growth efficiency and utilization of the boron source.Moreover,polydimethylsiloxane(PDMS)composites formed from these BNNTs demonstrated much greater thermal conductivities than pure PDMS.Thus,this novel strategy for preparing BNNTs is efficient,and they have great potential for application as thermal interface materials.
基金Financial supports from the National Key R&D Program of China(no.2017YFA0701301)the National Natural Science Foundation of China(nos.21922406,21775071,and 21632008)+2 种基金the Natural Science Foundation of Jiangsu Province(no.BK20190055)the Fundamental Research Funds for the Central Universities(no.020514380185)the Excellent Research Program of Nanjing University(no.ZYJH004)are acknowledged.
文摘Near-infrared(NIR)-II light-excitable photonic agents capable of generating tumor hyperthermia and cytotoxic free radicals are promising for synergistic phototherapy of tumors.However,the lack of NIR-II excitable agents makes it challenging to achieve combinational tumor phototherapy.Here,the authors have reported on a tumor-targeting and degradable hybrid copper sulfide(CuS)nanoparticle(AIBA@CuS-FA)via loading a hydrophilic Azo initiator(AIBA)into an amphiphilic lipid-encapsulating CuS nanoparticle.AIBA@CuS-FA shows high photothermal conversion efficiency(PCE≈47.5%)at 1064 nm,enabling heat production to trigger tumor hyperthermia and thermal decomposition of AIBA into cytotoxic free alkyl radicals upon irradiation with a 1064-nm laser under low-power density(0.5 W/cm2).Moreover,alkyl radicals can drive degradation of AIBA@CuS-FA and embedded CuS nanodisks,releasing Cu^(2+)ions that can catalyze a Fenton-like reaction for hydroxyl radical(•OH)production to promote tumor therapy.Findings demonstrate promise for combinational photothermal therapy(PTT),oxygen-independent alkyl radical therapy,and chemodynamic therapy(CDT)of tumors.
基金supported by the National Basic Research Program of China (2020YFA0210700 and 2016YFA0301004)the National Natural Science Foundation of China (21871009, 21527803, 22125102, and 22105218)Shanghai Sailing Program (21YF1454400)。
基金supported by the National Natural Science Foundation of China(Grant No.52073003)the Major Program of National Natural Science Foundation of China(Grant No.22090041)+1 种基金the National Key R&D Program of China(Grant No.2018YFA0305900)the Shanghai Sailing Program(Grant No.21YF1454400)。
文摘Symmetry breaking of metal cluster-based strongly correlated systems can give rise to collective phenomena.Here,the twodimensional Nb_(3) cluster compound Nb_(3)Cl_(8) is shown to suffer dramatic symmetry breaking and electron disproportionation under compression.A structural phase transition from trigonal P–3m1 to monoclinic C2/m is observed near 8 GPa with the three-fold symmetry breaking.Electron disproportionation occurs on Nb_(3) clusters from delocalized Nb^(8/3+)Nb^(8/3+)Nb^(8/3+)to localized Nb^(3+)Nb^(3+)Nb^(2+),which results in a subtle bandgap discontinuity,as evidenced by electrical transport and UV-Vis absorption measurements.