Developing electrolyte with high electrochemical stability is the most effective way to improve the energy density of double layer capacitors(DLCs), and ionic liquid is a promising choice. Herein, a novel ionic liquid...Developing electrolyte with high electrochemical stability is the most effective way to improve the energy density of double layer capacitors(DLCs), and ionic liquid is a promising choice. Herein, a novel ionic liquid based high potential electrolyte with a stabilizer, succinonitrile, was proposed to improve the high potential stability of the DLC. The electrolyte with 7.5 wt% succinonitrile added has a high ionic conductivity of 41.1 m S cm^(-1) under ambient temperature, and the DLC adopting this electrolyte could be charged to 3.0 V with stable cycle ability even under a discharge current density of 6 A g^(-1). Moreover, the energy density could be increased by 23.4% when the DLC was charged to 3.0 V compared to that charged to 2.7 V.展开更多
The influences of the time, temperature and atmosphere on the reduction swelling of oxidized pellets were investigated by single factor experiments. The mechanisms of reduction swelling of oxidized pellets were analyz...The influences of the time, temperature and atmosphere on the reduction swelling of oxidized pellets were investigated by single factor experiments. The mechanisms of reduction swelling of oxidized pellets were analyzed and investigated by SEM （scanning electron microscopy） and XRD （X-ray diffractometer） analysis. The results show that the change rules of reduction swelling index of oxidized pellets in different reduction atmospheres are very similar. With the increase of reduction time, the reduction swelling index moves up firstly and then down. When the reduction temperature is above 900 ℃, α-quartz turns into α-tridymite, and the transition generates additional volume expansion effect. The reduction swelling index changes faster in H2 atmosphere than in CO atmosphere. Increasing Ha content in the reduction atmosphere is useful to decrease the reduction swelling index, but it is also easy to cause oxidized pellets cracking.展开更多
Combining a progressive tandem junction design with a unique Si nanowire(SiNW)framework paves the way for the development of high‐onset‐potential photocathodes and enhancement of solar hydrogen production.Herein,a r...Combining a progressive tandem junction design with a unique Si nanowire(SiNW)framework paves the way for the development of high‐onset‐potential photocathodes and enhancement of solar hydrogen production.Herein,a radial tandem junction(RTJ)thin film water‐splitting photo‐cathode has been demonstrated experimentally for the first time.The photocathode is directly fab‐ricated on vapor‐liquid‐solid‐grown SiNWs and consists of two radially stacked p‐i‐n junctions,featuring hydrogenated amorphous silicon(a‐Si:H)as the outer absorber layer,which absorbs short wavelengths,and hydrogenated amorphous silicon germanium(a‐SiGe:H)as the inner layer,which absorbs long wavelengths.The randomly distributed SiNW framework enables highly efficient light‐trapping,which facilitates the use of very thin absorber layers of a‐Si:H(~50 nm)and a‐SiGe:H(~40 nm).In a neutral electrolyte(pH=7),the three‐dimensional(3D)RTJ photocathode delivers a high photocurrent onset of 1.15 V vs.the reversible hydrogen electrode(RHE),accompanied by a photocurrent of 2.98 mA/cm^(2) at 0 V vs.RHE,and an overall applied‐bias photon‐to‐current effi‐ciency of 1.72%.These results emphasize the promising role of 3D radial tandem technology in developing a new generation of durable,low‐cost,high‐onset‐potential photocathodes capable of large‐scale implementation。展开更多
A suitable carburized microstructure with fine granular dispersed carbides in hypereutectoid zone,ultra fine martensite in matrix and recrystallized austenite to be refined to the grain size of 12～14 has been obtaine...A suitable carburized microstructure with fine granular dispersed carbides in hypereutectoid zone,ultra fine martensite in matrix and recrystallized austenite to be refined to the grain size of 12～14 has been obtained by a new process,which is a high carbon concentration carburizing with rare earth element at low temperature(860～880℃)in a discontinuous gas carburization furnace.There was not much difference for the microstructure in eutectic zone between this and conventional process.Forming mechanism of granular carbides has been also studied in this paper.展开更多
Thermodynamic concepts required for the thermodynamic calculation of the potentials of electrodes for high temperature applications are briefly reviewed. A thermodynamic approach to the calculation of half cell potent...Thermodynamic concepts required for the thermodynamic calculation of the potentials of electrodes for high temperature applications are briefly reviewed. A thermodynamic approach to the calculation of half cell potentials and the standard chemical potential of an electron at high temperatures which are related to the Standard Hydrogen Electrode(SHE) is discussed. As examples, an external Ag/AgCl reference electrode and a YSZ(Ag|O_2) pH sensor for high temperature applications are analyzed by using the thermodynamic approach to derive a high temperature pH measurement equation. The two electrodes are employed to measure high temperature pH and the measured pH was compared with the calculated pH by using a solution chemistry method. Concepts and principles for electrode kinetics are also briefly introduced and a modification to the Tafel equations is suggested.展开更多
Low specific capacitances and/or limited working potential(≤4.5 V).of the prevalent carbon-based positive electrodes as the inborn bottleneck seriously hinder practical advancement of lithium-ion capacitors.Thus,brea...Low specific capacitances and/or limited working potential(≤4.5 V).of the prevalent carbon-based positive electrodes as the inborn bottleneck seriously hinder practical advancement of lithium-ion capacitors.Thus,breakthroughs in enhancement of both specific capacitances and upper cutoff potentials are enormously significant for high-energy density lithium-ion capacitors.Herein,we first meticulously design and scalably fabricate a commercializable fluorine-doped porous carbon material with competitive tap density,large active surface,appropriate aperture distribution,and promoted affinity with the electrolyte,rendering its abundant electroactive inter-/surface and rapid PF_(6)^(-)transport.Theoretical calculations authenticate that fluorine-doped porous carbon possesses lower PF_(6)^(-)adsorption energy and stronger interaction with PF_(6)^(-).Thanks to the remarkable structural/compositional superiority,when served as a positive electrode toward lithium-ion capacitors,the commercial-level fluorine-doped porous carbon showcases the record-breaking electrochemical properties within a wider working window of 2.5-5.0 V(vs Li/Li^(+))in terms of high-rate specific capacitances and long-duration stability,much superior to commercial activated carbon.More significantly,the 4.5 V-class graphite//fluorine-doped porous carbon lithium-ion capacitors are first constructed and manifest competitive electrochemical behaviors with long-cycle life,modest polarization,and large energy density.Our work provides a commendable positive paradigm and contributes a major step forward in next-generation lithium-ion capacitors and even other high-energy density metal-ion capacitors.展开更多
The great Wenchuan （汶川） earthquake induced a large quantity of landslides. They are widely distributed and caused tremendous damages. The sliding mechanism and characteristics of these earthquake-induced landslide...The great Wenchuan （汶川） earthquake induced a large quantity of landslides. They are widely distributed and caused tremendous damages. The sliding mechanism and characteristics of these earthquake-induced landslides are different from those of conventional gravity landslides. Their occurrences are apparently controlled by the powerful earthquake, and they are characterized by high potential energy sliding and ejection sliding. In this article, the earthquake-induced landslides are classified, the characteristics of the sliding and destruction of these landslides are described, and the rela- tionship between the earthquake and the landslides is analyzed. The Donghekou （东河口） landslide is used as an example to characterize fast-moving long-distance earthquake-induced ejection slippage and landslide. This research suggests that many phenomena and issues related to earthquake-induced land- slide are beyond current recognition and knowledge, and new methodologies should be adopted to consider the effect of the earthquake as the paramount factor in the development of landslides. Furthermore, the study of fast-moving long-distance earthquake-induced landslides can also shed light on the formation of old and ancient landslides.展开更多
Background： Biotherapy based on human bone marrow-derived mesenchymal stem cells （BMSCs） is currently the focus of research, especially in the field of autologous stem cell transplantation. A novel type of metastas...Background： Biotherapy based on human bone marrow-derived mesenchymal stem cells （BMSCs） is currently the focus of research, especially in the field of autologous stem cell transplantation. A novel type of metastasis-associated magnetic resonance （MR） molecular imaging probe was constructed, and the changes in metastasis and proliferation of hepatocellular carcinoma （HCC） before and after BMSC intervention were observed through MR imaging （MRI）. Methods：Metastasis-associatedMRmolecularimagingprobe,integrin αvβ3 ligandcRGD-PEG-DGL-DTPA-Gd （Gd-RGD）,wereconstructed. After human BMSC intervention was performed for 6weeks, tumor weight inhibition rates were calculated, and the RGD molecular probe was imaged through MRI with molecular imaging agent Gd-DTPAas control.The signal-to-noise ratio （SNR） and contrast-to-noise ratio （CNR） in the MRI experiment were used as semi-quantitative indicators. Polymerase chain reaction method was performed to detect proliferation- and metastasis-associated indicators, transforming growth factor β-1 （TGFβ1）, osteopontin （OPN）, and integrin subunit αv and β3. Results： The highest tumor weight inhibition rates were observed 3 weeks after the BMSC transplantation. The MR Gd-RGD in the HCC tissues after the BMSC intervention showed less enhancement than Gd-DTPA. The Gd-DTPAMRI of control group had higher SNR and CNR than Gd-RGD MRI in the experimental groups （P 〈 0.05）. For high metastatic potential hepatocellular carcinoma （MHCC97-H）, significant differenceswereobservedintheSNRsandCNRsofGd-RGDMRIbeforeandaftertheBMSCintervention（P〈0.05）.Forlowmetastaticpotential hepatocellular carcinoma （MHCC97-L）, the CNRs of Gd-RGD MRI were statistically different before and after BMSC intervention （P 〈 0.05）. With regard to MHCC97-H, OPN, β3, and TGFβ1 expression significantly decreased after BMSC intervention （P 〈 0.05）. In MHCC97-L and OPN, β3, TGFβ1, and αv expression after BMSC intervention decreased, and the difference was statistically significant （P 〈 0.05）. Conclusions： The CNR index of MRI is a good indicator for distinguishing high- and low-metastatic potential HCC tissues.After BMSC transplantation of MRI through the two kinds of tracer, the SNR and CNR indexes can distinguish two kinds of high and low metastatic potential HCC tissues, and Gd-RGD imaging is more suitable in distinguishing the metastatic potential changes through BMSC intervention.展开更多
A bound state formalism derived from a fermion-boson symmetric Lagrangian has been used to calculate the nucleon masses, the charge neutrality of the neutron, the magnetic moments and the electromagnetic form factor r...A bound state formalism derived from a fermion-boson symmetric Lagrangian has been used to calculate the nucleon masses, the charge neutrality of the neutron, the magnetic moments and the electromagnetic form factor ratios μpGEp/GMpand μnGEn/GMn. A quantitative description is obtained, assuming a mixing of a scalar bound state of 3(f f¯)fstructure with its corresponding vector (f f¯)fstate (f indicating massless elementary fermions). Only a few parameters are needed, mainly fixed by energy and momentum conservation. The nucleon stability is explained by an extra binding in the confinement potential, negative for electric and positive for magnetic binding of the proton, and opposite for the neutron. The stronger electric extra binding of the proton allows a decay of the neutron to proton and electron.展开更多
Iron-based sulfates have emerged as promising cathode materials for potassium-ion batteries due to their low cost,high working potential,and environmentally friendly.However,the relatively large ionic radius and slugg...Iron-based sulfates have emerged as promising cathode materials for potassium-ion batteries due to their low cost,high working potential,and environmentally friendly.However,the relatively large ionic radius and sluggish diffusion coefficient of K-ion pose significant challenges to the electrochemical performance and structural stability of cathode materials in potassium-ion batteries(PIBs).In this work,we successfully synthesis a new iron-based sulfate cathode material,potassium sodium iron sulfate(K_(1.66)Na_(1.02)Fe_(1.66)(SO_(4))_(3),KNFS),through an electro-chemical ion exchange method.As a cathode material,it exhibits a reversible specific capacity of 83 mAh·g^(−1) and an average working potential of 3.84 V(vs.K/K^(+))at 0.1 C in PIBs.Even at 2 C,it still demonstrates a reversible specific capacity of 52 mAh·g^(−1) with a capacity retention ratio of 88.2%after 300 cycles.The in-situ X-ray diffraction(XRD)and ex-situ X-ray absorption spectroscopy reveal that the K-ion storage mechanism in KNFS is predominantly governed by the reversible Fe^(3+)/Fe^(2+) redox couple,which provides a theoretical specific capacity of 94 mAh·g^(−1) and involves minimal volume change(2.57%).The first-principles calculations combined with XRD results indicate that the KNFS cathode exhibits a typical alluaudite-type crystal structure with multiple fast K-ion migration channels along the three-dimensional orientation.展开更多
基金supported by the International S&T Cooperation Program of China (2014DFA61670)the Key Program of National Natural Science Foundation of China (91434203)+1 种基金the International Cooperation and Exchange of the National Natural Science Foundation of China (51561145020)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA09010103)
文摘Developing electrolyte with high electrochemical stability is the most effective way to improve the energy density of double layer capacitors(DLCs), and ionic liquid is a promising choice. Herein, a novel ionic liquid based high potential electrolyte with a stabilizer, succinonitrile, was proposed to improve the high potential stability of the DLC. The electrolyte with 7.5 wt% succinonitrile added has a high ionic conductivity of 41.1 m S cm^(-1) under ambient temperature, and the DLC adopting this electrolyte could be charged to 3.0 V with stable cycle ability even under a discharge current density of 6 A g^(-1). Moreover, the energy density could be increased by 23.4% when the DLC was charged to 3.0 V compared to that charged to 2.7 V.
基金Sponsored by National Natural Science Foundation of China(51104014)National Natural Science Foundation of China and Baosteel(51134008)National Basic Research Program(973Program)of China(2012CB720401)
文摘The influences of the time, temperature and atmosphere on the reduction swelling of oxidized pellets were investigated by single factor experiments. The mechanisms of reduction swelling of oxidized pellets were analyzed and investigated by SEM （scanning electron microscopy） and XRD （X-ray diffractometer） analysis. The results show that the change rules of reduction swelling index of oxidized pellets in different reduction atmospheres are very similar. With the increase of reduction time, the reduction swelling index moves up firstly and then down. When the reduction temperature is above 900 ℃, α-quartz turns into α-tridymite, and the transition generates additional volume expansion effect. The reduction swelling index changes faster in H2 atmosphere than in CO atmosphere. Increasing Ha content in the reduction atmosphere is useful to decrease the reduction swelling index, but it is also easy to cause oxidized pellets cracking.
文摘Combining a progressive tandem junction design with a unique Si nanowire(SiNW)framework paves the way for the development of high‐onset‐potential photocathodes and enhancement of solar hydrogen production.Herein,a radial tandem junction(RTJ)thin film water‐splitting photo‐cathode has been demonstrated experimentally for the first time.The photocathode is directly fab‐ricated on vapor‐liquid‐solid‐grown SiNWs and consists of two radially stacked p‐i‐n junctions,featuring hydrogenated amorphous silicon(a‐Si:H)as the outer absorber layer,which absorbs short wavelengths,and hydrogenated amorphous silicon germanium(a‐SiGe:H)as the inner layer,which absorbs long wavelengths.The randomly distributed SiNW framework enables highly efficient light‐trapping,which facilitates the use of very thin absorber layers of a‐Si:H(~50 nm)and a‐SiGe:H(~40 nm).In a neutral electrolyte(pH=7),the three‐dimensional(3D)RTJ photocathode delivers a high photocurrent onset of 1.15 V vs.the reversible hydrogen electrode(RHE),accompanied by a photocurrent of 2.98 mA/cm^(2) at 0 V vs.RHE,and an overall applied‐bias photon‐to‐current effi‐ciency of 1.72%.These results emphasize the promising role of 3D radial tandem technology in developing a new generation of durable,low‐cost,high‐onset‐potential photocathodes capable of large‐scale implementation。
文摘A suitable carburized microstructure with fine granular dispersed carbides in hypereutectoid zone,ultra fine martensite in matrix and recrystallized austenite to be refined to the grain size of 12～14 has been obtained by a new process,which is a high carbon concentration carburizing with rare earth element at low temperature(860～880℃)in a discontinuous gas carburization furnace.There was not much difference for the microstructure in eutectic zone between this and conventional process.Forming mechanism of granular carbides has been also studied in this paper.
文摘Thermodynamic concepts required for the thermodynamic calculation of the potentials of electrodes for high temperature applications are briefly reviewed. A thermodynamic approach to the calculation of half cell potentials and the standard chemical potential of an electron at high temperatures which are related to the Standard Hydrogen Electrode(SHE) is discussed. As examples, an external Ag/AgCl reference electrode and a YSZ(Ag|O_2) pH sensor for high temperature applications are analyzed by using the thermodynamic approach to derive a high temperature pH measurement equation. The two electrodes are employed to measure high temperature pH and the measured pH was compared with the calculated pH by using a solution chemistry method. Concepts and principles for electrode kinetics are also briefly introduced and a modification to the Tafel equations is suggested.
基金support from the National Natural Science Foundation of China(Grant No.U22A20145,51904115,52072151,52171211,52102253,and 52271218)Jinan Independent Innovative Team(2020GXRC015)Major Program of Shandong Province Natural Science Foundation(ZR2023ZD43,ZR2021ZD05).
文摘Low specific capacitances and/or limited working potential(≤4.5 V).of the prevalent carbon-based positive electrodes as the inborn bottleneck seriously hinder practical advancement of lithium-ion capacitors.Thus,breakthroughs in enhancement of both specific capacitances and upper cutoff potentials are enormously significant for high-energy density lithium-ion capacitors.Herein,we first meticulously design and scalably fabricate a commercializable fluorine-doped porous carbon material with competitive tap density,large active surface,appropriate aperture distribution,and promoted affinity with the electrolyte,rendering its abundant electroactive inter-/surface and rapid PF_(6)^(-)transport.Theoretical calculations authenticate that fluorine-doped porous carbon possesses lower PF_(6)^(-)adsorption energy and stronger interaction with PF_(6)^(-).Thanks to the remarkable structural/compositional superiority,when served as a positive electrode toward lithium-ion capacitors,the commercial-level fluorine-doped porous carbon showcases the record-breaking electrochemical properties within a wider working window of 2.5-5.0 V(vs Li/Li^(+))in terms of high-rate specific capacitances and long-duration stability,much superior to commercial activated carbon.More significantly,the 4.5 V-class graphite//fluorine-doped porous carbon lithium-ion capacitors are first constructed and manifest competitive electrochemical behaviors with long-cycle life,modest polarization,and large energy density.Our work provides a commendable positive paradigm and contributes a major step forward in next-generation lithium-ion capacitors and even other high-energy density metal-ion capacitors.
文摘The great Wenchuan （汶川） earthquake induced a large quantity of landslides. They are widely distributed and caused tremendous damages. The sliding mechanism and characteristics of these earthquake-induced landslides are different from those of conventional gravity landslides. Their occurrences are apparently controlled by the powerful earthquake, and they are characterized by high potential energy sliding and ejection sliding. In this article, the earthquake-induced landslides are classified, the characteristics of the sliding and destruction of these landslides are described, and the rela- tionship between the earthquake and the landslides is analyzed. The Donghekou （东河口） landslide is used as an example to characterize fast-moving long-distance earthquake-induced ejection slippage and landslide. This research suggests that many phenomena and issues related to earthquake-induced land- slide are beyond current recognition and knowledge, and new methodologies should be adopted to consider the effect of the earthquake as the paramount factor in the development of landslides. Furthermore, the study of fast-moving long-distance earthquake-induced landslides can also shed light on the formation of old and ancient landslides.
文摘Background： Biotherapy based on human bone marrow-derived mesenchymal stem cells （BMSCs） is currently the focus of research, especially in the field of autologous stem cell transplantation. A novel type of metastasis-associated magnetic resonance （MR） molecular imaging probe was constructed, and the changes in metastasis and proliferation of hepatocellular carcinoma （HCC） before and after BMSC intervention were observed through MR imaging （MRI）. Methods：Metastasis-associatedMRmolecularimagingprobe,integrin αvβ3 ligandcRGD-PEG-DGL-DTPA-Gd （Gd-RGD）,wereconstructed. After human BMSC intervention was performed for 6weeks, tumor weight inhibition rates were calculated, and the RGD molecular probe was imaged through MRI with molecular imaging agent Gd-DTPAas control.The signal-to-noise ratio （SNR） and contrast-to-noise ratio （CNR） in the MRI experiment were used as semi-quantitative indicators. Polymerase chain reaction method was performed to detect proliferation- and metastasis-associated indicators, transforming growth factor β-1 （TGFβ1）, osteopontin （OPN）, and integrin subunit αv and β3. Results： The highest tumor weight inhibition rates were observed 3 weeks after the BMSC transplantation. The MR Gd-RGD in the HCC tissues after the BMSC intervention showed less enhancement than Gd-DTPA. The Gd-DTPAMRI of control group had higher SNR and CNR than Gd-RGD MRI in the experimental groups （P 〈 0.05）. For high metastatic potential hepatocellular carcinoma （MHCC97-H）, significant differenceswereobservedintheSNRsandCNRsofGd-RGDMRIbeforeandaftertheBMSCintervention（P〈0.05）.Forlowmetastaticpotential hepatocellular carcinoma （MHCC97-L）, the CNRs of Gd-RGD MRI were statistically different before and after BMSC intervention （P 〈 0.05）. With regard to MHCC97-H, OPN, β3, and TGFβ1 expression significantly decreased after BMSC intervention （P 〈 0.05）. In MHCC97-L and OPN, β3, TGFβ1, and αv expression after BMSC intervention decreased, and the difference was statistically significant （P 〈 0.05）. Conclusions： The CNR index of MRI is a good indicator for distinguishing high- and low-metastatic potential HCC tissues.After BMSC transplantation of MRI through the two kinds of tracer, the SNR and CNR indexes can distinguish two kinds of high and low metastatic potential HCC tissues, and Gd-RGD imaging is more suitable in distinguishing the metastatic potential changes through BMSC intervention.
文摘A bound state formalism derived from a fermion-boson symmetric Lagrangian has been used to calculate the nucleon masses, the charge neutrality of the neutron, the magnetic moments and the electromagnetic form factor ratios μpGEp/GMpand μnGEn/GMn. A quantitative description is obtained, assuming a mixing of a scalar bound state of 3(f f¯)fstructure with its corresponding vector (f f¯)fstate (f indicating massless elementary fermions). Only a few parameters are needed, mainly fixed by energy and momentum conservation. The nucleon stability is explained by an extra binding in the confinement potential, negative for electric and positive for magnetic binding of the proton, and opposite for the neutron. The stronger electric extra binding of the proton allows a decay of the neutron to proton and electron.
基金funded by the Science and Technology Commission of Shanghai Municipality(No.19D.Z.2271100)the China Postdoctoral Science Foundation(No.2024M750490)The authors would like to express their sincere gratitude to Ms.Li from Scientific Compass(www.shiyanjia.com)for her valuable assistance in XPS testing.
文摘Iron-based sulfates have emerged as promising cathode materials for potassium-ion batteries due to their low cost,high working potential,and environmentally friendly.However,the relatively large ionic radius and sluggish diffusion coefficient of K-ion pose significant challenges to the electrochemical performance and structural stability of cathode materials in potassium-ion batteries(PIBs).In this work,we successfully synthesis a new iron-based sulfate cathode material,potassium sodium iron sulfate(K_(1.66)Na_(1.02)Fe_(1.66)(SO_(4))_(3),KNFS),through an electro-chemical ion exchange method.As a cathode material,it exhibits a reversible specific capacity of 83 mAh·g^(−1) and an average working potential of 3.84 V(vs.K/K^(+))at 0.1 C in PIBs.Even at 2 C,it still demonstrates a reversible specific capacity of 52 mAh·g^(−1) with a capacity retention ratio of 88.2%after 300 cycles.The in-situ X-ray diffraction(XRD)and ex-situ X-ray absorption spectroscopy reveal that the K-ion storage mechanism in KNFS is predominantly governed by the reversible Fe^(3+)/Fe^(2+) redox couple,which provides a theoretical specific capacity of 94 mAh·g^(−1) and involves minimal volume change(2.57%).The first-principles calculations combined with XRD results indicate that the KNFS cathode exhibits a typical alluaudite-type crystal structure with multiple fast K-ion migration channels along the three-dimensional orientation.
