Electrocatalyst activity and stability demonstrate a“seesaw”relationship.Introducing vacancies(Vo)enhances the activity by improving reactant affinity and increasing accessible active sites.However,deficient or exce...Electrocatalyst activity and stability demonstrate a“seesaw”relationship.Introducing vacancies(Vo)enhances the activity by improving reactant affinity and increasing accessible active sites.However,deficient or excessive Vo reduces polysulfide adsorption and lowers catalytic stability.Herein,a novel“heteroatoms synergistic anchoring vacancies”strategy is proposed to address the trade-off between high activity and stability.Phosphorus-doped CoSe_(2)with remained rich selenium vacancies(P-CS-Vo-0.5)was synthesized by producing abundant selenium Vo followed by controlled P atom doping.Atomic-scale microstructure analysis elucidated a dynamic process of surface vacancy generation and the subsequent partial occupation of these vacancies by P atoms.Density functional theory simulations and in situ Raman tests revealed that the Se vacancies provide highly active catalytic sites,accelerating polysulfide conversion,while P incorporation effectively reduces the surface energy of Se vacancies and suppresses their inward migration,enhancing structural robustness.The battery with the optimal P-CS-Vo-0.5 separator delivers an initial discharge capacity of 1306.7 mAh g^(-1)at 0.2C,and maintain 5.04 mAh cm^(-2)at a high sulfur loading(5.7 mg cm^(-2),5.0μL mg^(-1)),achieving 95.1%capacity retention after 80 cycles.This strategy of modifying local atomic environments offers a new route to designing highly active and stable catalysts.展开更多
Polymeric-inorganic nanocomposite catalysts were synthesized by facile one-pot chemical polymerization of pyrrole in the presence of titanium dioxide nanoparticles. The electrical, optical, photovoltaic performance of...Polymeric-inorganic nanocomposite catalysts were synthesized by facile one-pot chemical polymerization of pyrrole in the presence of titanium dioxide nanoparticles. The electrical, optical, photovoltaic performance of dye sensitized solar cell（DSSC） and visible light driven photocatalytic activities of the nanocomposite were investigated. The prepared nanocomposite displays excellent photo-activity, attaining 100% degradation of methyl orange dye in 60 min under visible light source while 55% for pure TiO_2 under similar experimental conditions. The photovoltaic performance of the polypyrrole-titanium dioxide（PPy-TiO_2） nanocomposite has a 51.4% improvement with a photo-conversion efficiency of 8.07% as compared to pure TiO_2 based DSSC. By comparing the physical mixture of the PPy-TiO_2 nanocomposite and pristine TiO_2, the enhanced activity of the PPy-TiO_2 nanocomposite can be attributed to the reduced charge transfer resistance, outstanding electrical conductance of the PPy, the nano-sized structure of TiO_2 and their synergetic effect. Furthermore, the PPy-TiO_2 nanocomposite shows excellent electrical conductivity and isothermal stability under ambient conditions below 110？C.展开更多
Cobalt-based phosphides show excellent hydrogen evolution reaction(HER)performance,however,improving the intrinsic activity and stability of it in alkaline electrolyte still remains a challenge.Herein,CoRuOH/Co_(2)P/C...Cobalt-based phosphides show excellent hydrogen evolution reaction(HER)performance,however,improving the intrinsic activity and stability of it in alkaline electrolyte still remains a challenge.Herein,CoRuOH/Co_(2)P/CF with heterojunction structure was developed by means of molten salt and rapid hydrolysis(30 s).The OH-from rapid surface hydrolysis of Co_(2)P as a hydrogen adsorption site can facilitate the formation of thin CoRuOH layer as a water dissociation site,which may bring out better synergistic effect for alkaline HER.Moreover,the covering of CoRuOH can improve the stability of Co_(2)P for HER.When drives at 100 mA/cm^(2),it only requires overpotential of 81 mV in 1.0 mol/L KOH(25℃).Even at higher current density(1000 mA/cm^(2)),CoRuOH/Co_(2)P/CF can also operate stability for at least 100 h.When coupling with NiFe-LDH/IF in a two-electrode system,the voltage of NiFe-LDH/IF(+)||CoRuOH/Co_(2)P/CF(-)at 1000 mA/cm^(2)is merely 1.77 V with 100 h,demonstrating great potential for water splitting.The implementation of this work provides a new strategy and reference for the further improvement of transition metal phosphides as HER electrocatalysts.展开更多
The effect of oxygen partial pressure （Po2） during the channel layer deposition on bias stability of amorphous indium-gallium-zinc oxide （a-IGZO） thin film transistors （TFTs） is investigated. As Po2 increases fr...The effect of oxygen partial pressure （Po2） during the channel layer deposition on bias stability of amorphous indium-gallium-zinc oxide （a-IGZO） thin film transistors （TFTs） is investigated. As Po2 increases from 10% to 30%, it is found that the device shows enhanced bias stress stability with significantly reduced threshold voltage drift under positive gate bias stress. Based on the x-ray photoelectron spectroscopy measurement, the concentration of oxygen vacancies （Or） within the a-IGZO layer is suppressed by increasing Po2. Meanwhile, the low-frequency noise analysis indicates that the average trap density near the channel/dielectric interface continuously drops with increasing Po2. Therefore, the improved interface quality with increasing Po2 during the channel layer deposition can be attributed to the reduction of interface Ov-related defects, which agrees with the enhanced bias stress stability of the a-IGZO TFTs.展开更多
The temperature stability of supercapacitor（SC） is largely determined by the properties of the electrolyte.Hydrogel electrolytes（HGE）, due to their hydrophilic polymer skeleton, show different temperature stabilit...The temperature stability of supercapacitor（SC） is largely determined by the properties of the electrolyte.Hydrogel electrolytes（HGE）, due to their hydrophilic polymer skeleton, show different temperature stability to that of liquid aqueous electrolytes. In this study, symmetric activated carbon（AC） SCs had been assembled with in situ electrodeposited poly（vinyl alcohol） potassium borate（PVAPB） HGE. The electrochemical performance of the SCs was systematically studied at different temperatures. Results show that the conductivity of PVAPB HGE is comparable with that of liquid aqueous electrolytes at different temperatures. The operating temperature range of PVAPB HGE SCs is -5–60°C, while those of the 1 mol/L Na2SO4SCs and the 0.9 mol/L KClSCs are 20–80°C and 20–40°C, respectively. The specific capacitance of PVAPB HGE SC is higher than those of SCs using liquid aqueous electrolytes at any temperature. The excellent temperature stability of PVAPB HGE makes it possible to build stable aqueous SCs in the wider temperature range.展开更多
This paper puts forward a high-speed train bogie active stability method,based on frame lateral vibration control,for improving the stability and critical speed of railway vehicles at high speeds.Two inertial actuator...This paper puts forward a high-speed train bogie active stability method,based on frame lateral vibration control,for improving the stability and critical speed of railway vehicles at high speeds.Two inertial actuators apply active control forces to the front and rear end beams of the bogie frame.A scale model of bogie lateral dynamics is established,as well as the state space equation of the control system.Also,the multi-objective optimization is used to construct state feedback parameters,which take hunting stability and control effort into account.Furthermore,the effects of time-delay in the control system and suspension parameters on bogie hunting stability are studied.The dynamic behaviors and the stability mechanism of the bogie control system are analyzed.Finally,a 1:5 scale test rig is used to conduct a bogie active stability experiment.The results reveal that active control of frame lateral vibration can effectively improve the bogie system's hunting stability margin at high speeds,but time-delay in the control system cannot be ignored.展开更多
The presynaptic active zone is a dynamic structure that orchestrates regulated release of neurotrans- mitters. Developmental and aging processes, and changes in neuronal network activity can all modulate the number, s...The presynaptic active zone is a dynamic structure that orchestrates regulated release of neurotrans- mitters. Developmental and aging processes, and changes in neuronal network activity can all modulate the number, size and composition of active zone and thereby synaptic efficacy. However, very little is known about the mechanism that controls the structural stability of active zone. By study- ing a model synapse, the Drosophila neuromuscular iunction, our recent work shed light on how two scaffolding proteins at the active zone regulate active zone stability by promoting a localized dephos- phorylation event at the nerve terminal. Here we discuss the major insights from our findings and their implications for future research.展开更多
The multifunctional trans-activator Tat is an essential regulatory protein for HIV-1 replication and is characterized by high sequence diversity. Numerous experimental studies have examined Tat in HIV-1 subtype B, but...The multifunctional trans-activator Tat is an essential regulatory protein for HIV-1 replication and is characterized by high sequence diversity. Numerous experimental studies have examined Tat in HIV-1 subtype B, but research on subtype C Tat is lacking, despite the high prevalence of infections caused by subtype C worldwide. We hypothesized that amino acid differences contribute to functional differences among Tat proteins. In the present study, we found that subtype B NL4-3Tat and subtype C isolate HIV1084 i Tat exhibited differences in stability by overexpressing the fusion protein Tat-Flag. In addition, 1084 i Tat can activate LTR and NF-κB more efficiently than NL4-3 Tat. In analyses of the activities of the truncated forms of Tat, we found that the carboxylterminal region of Tat regulates its stability and transactivity. According to our results, we speculated that the differences in stability between B-Tat and C-Tat result in differences in transactivation ability.展开更多
Active metamaterials incorporating with non-Foster elements have been considered as one of the means of overcoming inherent limitations of the passive counterparts, thus achieving broadband or gain metamaterials. Howe...Active metamaterials incorporating with non-Foster elements have been considered as one of the means of overcoming inherent limitations of the passive counterparts, thus achieving broadband or gain metamaterials. However, realistic active metamaterials, especially non-Foster loaded medium, would face the challenge of the possibility of instability. Moreover,they normally appear to be time-variant and in unsteady states, which leads to the necessity of a stability method to cope with the stability issue considering the system model uncertainty. In this paper, we propose an immittance-based stability method to design a non-Foster loaded metamaterial ensuring robust stability. First, the principle of this stability method is introduced after comparing different stability criteria. Based on the equivalent system model, the stability characterization is used to give the design specifications to achieve an active metamaterial with robust stability. Finally, it is applied to the practical design of active metamaterial with non-Foster loaded loop arrays. By introducing the disturbance into the nonFoster circuit（NFC）, the worst-case model uncertainty is considered during the design, and the reliability of our proposed method is verified. This method can also be applied to other realistic design of active metamaterials.展开更多
Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness o...Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness of OER and the high prices as well as the scarcity of the most active precious metal electrocatalysts are the major bottleneck in these devices. Developing low-cost non-precious metal catalysts with high activity and stability for OER is highly desirable. A facile, in situ template method combining the dodecyl benzene sulfuric acid sodium（SDBS） assisted hydrothermal process with subsequent high-temperature treatment was developed to prepare porous Co3O4 with improved surface area and hierarchical porous structure as precious catalysts alternative for oxygen evolution reaction（OER）. Due to the unique structure, the as-prepared catalyst shows higher electrocatalytic activity than Co3O4 prepared by traditional thermal-decomposition method（noted as Co3O4-T） and commercial IrO2 catalyst for OER in 0.1M KOH aqueous solution. Moreover, it displays improved stability than Co3O4-T. The results demonstrate a highly efficient, scalable, and low cost method for developing highly active and stable OER electrocatalysts in alkaline solutions.展开更多
The Qinghai-Tibet Plateau(QTP)distributes the largest extent of high-altitude mountain permafrost in the world(Zou et al.,2017),which has different characteristics from high-latitude permafrost(Yang et al.,2010)and st...The Qinghai-Tibet Plateau(QTP)distributes the largest extent of high-altitude mountain permafrost in the world(Zou et al.,2017),which has different characteristics from high-latitude permafrost(Yang et al.,2010)and stores massive soil carbon.展开更多
After publication of the research article "Constructing inter diffusive PtCuNi/WOg interface to enhance the catalytic activity and stability in oxygen reduction"(https://doi.org/10.1007/s42864-023-00226-0).T...After publication of the research article "Constructing inter diffusive PtCuNi/WOg interface to enhance the catalytic activity and stability in oxygen reduction"(https://doi.org/10.1007/s42864-023-00226-0).The authors discovered that the"Acknowledgement"is missing from the published online version,due to the unintentional mistake when preparing the manuscript.This could be unfair to the entities/scholars providing meaningful help to this work,as well as the funding agency that provided the financial support to this work.Therefore,an erratum is requested by the authors to acknowledge the following parties.展开更多
A comprehensive understanding of the dynamic processes at the catalyst/electrolyte interfaces is crucial for the development of advanced electrocatalysts for the oxygen evolution reaction(OER).However,the chemical pro...A comprehensive understanding of the dynamic processes at the catalyst/electrolyte interfaces is crucial for the development of advanced electrocatalysts for the oxygen evolution reaction(OER).However,the chemical processes related to surface corrosion and catalyst degradation have not been well understood so far.In this study,we employ LiCoO_(2) as a model catalyst and observe distinct OER activities and surface stabilities in different alkaline solutions.Operando X-ray diffraction(XRD)and online mass spectroscopy(OMS)measurements prove the selective intercalation of alkali cations into the layered structure of LiCoO_(2) during OER.It is proposed that the dynamic cation intercalations facilitate the chemical oxidation process between highly oxidative Co species and adsorbed water molecules,triggering the so-called electrochemical-chemical reaction mechanism(EC-mechanism).The results of this study emphasize the influence of cations on OER and provide insights into new strategies for achieving both high activity and stability in high-performance OER catalysts.展开更多
Proton exchange membrane water electrolysis(PEMWE)technology is widely recognized as a cornerstone for green hydrogen production,offering high operational current densities exceeding 1.0 A cm^(-2),rapid dynamic respon...Proton exchange membrane water electrolysis(PEMWE)technology is widely recognized as a cornerstone for green hydrogen production,offering high operational current densities exceeding 1.0 A cm^(-2),rapid dynamic response capabilities,and zero-carbon emission characteristics[1].However,the sluggish kinetics of oxygen evolution reaction(OER)at the anode presents a critical bottleneck for large-scale commercial deployment(Fig.1(a)).Despite significant advancements through electronic structure modulation[2]and coordination environment optimization[3],the deprotonation energy barrier of oxygen-containing intermediates and the stability of active sites under acidic conditions remain unresolved challenges.展开更多
The performance of the two newly developed bimetallic catalysts based on the precursor, Mo/Al_2O_3, was compared for reverse water gas shift(RWGS) reaction. The structures of the precursor and the catalysts were studi...The performance of the two newly developed bimetallic catalysts based on the precursor, Mo/Al_2O_3, was compared for reverse water gas shift(RWGS) reaction. The structures of the precursor and the catalysts were studied using X-ray diffraction(XRD), Brunauer–Emmett–Teller(BET) analysis, inductively coupled plasma-atomic emission spectrometry(ICP-AES), CO chemisorption, temperature programmed reduction of hydrogen(H_2-TPR) and scanning electron microscopy(SEM) techniques. The activity of Fe-Mo and Co-Mo catalysts was compared in a fixed bed reactor at different temperatures. It is shown that the Co-Mo catalyst has higher CO_2 conversion at all temperature level. The time-on-stream(TOS) analysis of the activity of catalysts for the RWGS reaction was carried out over a continuous period of 60h for both catalysts. The Fe-Mo/Al_2O_3 catalyst exhibits good stability within a period of 60h, however, the Co-Mo/Al_2O_3 is gradually deactivated after 50h of reaction time. Existence of(Fe_2(MoO4_))_3 phase in Fe-Mo/Al_2O_3 catalyst makes this catalyst more stable for RWGS reaction.展开更多
The tumor suppressor p53 is a multifunctional, highly regulated, and promoter-specific transcriptional factor that is uniquely sensitive to DNA damage and cellular stress signaling. The mechanisms by which p53 directs...The tumor suppressor p53 is a multifunctional, highly regulated, and promoter-specific transcriptional factor that is uniquely sensitive to DNA damage and cellular stress signaling. The mechanisms by which p53 directs a damaged cell down either a cell growth arrest or an apoptotic pathway remain poorly understood. Evidence suggests that the in vivo functions of p53 seem to balance the cell-fate choice with the type and severity of damage that occurs. The concept of antirepression, or inhibition of factors that normally keep p53 at bay, may help explain the physiological mechanisms for p53 activation. These factors also provide novel chemotherapeutic targets for the reactivation of p53 in tumors harboring a wild-type copy of the gene.展开更多
While double perovskites of PrBaCo_(2)O_(6)(PBC)have been extensively developed as the cathodes for proton-conducting solid oxide fuel cells(H-SOFCs),the effects of Sr-or Ca-doping at the A site on the activity and st...While double perovskites of PrBaCo_(2)O_(6)(PBC)have been extensively developed as the cathodes for proton-conducting solid oxide fuel cells(H-SOFCs),the effects of Sr-or Ca-doping at the A site on the activity and stability of the oxygen reduction reaction are yet to be fully studied.Here,the effect of A-site doping on the oxygen reduction reaction activity and stability has been studied by evaluating the performance of both symmetrical and single cells.It is shown that Ca-doped PBC(PrBa_(0.8)Ca_(0.2)Co_(2)O_(6),PBCC)shows a slightly smaller polarization resistance(0.076Ωcm^(2))than that(0.085Ωcm^(2))of Sr-doped PBC(PrBa0.8Sr0.2Co2O6,PBSC)at 700◦C in wet air.Moreover,the degradation rate of PBCC is 0.0003Ωcm^(2)h^(−1)(0.3%h−1)in 100 h,about 1/10 of that of PBSC at 700◦C in wet air.In addition,it is also confirmed that single cells with PBCC cathode show higher peak power density(1.22Wcm^(−2)vs.1.08Wcm^(−2)at 650◦C)and better durability(degradation rate of 0.1%h^(−1)vs.0.13%h^(−1))than those with PBSC cathode.The distribution of relaxation time analyses suggests that the better stability of the PBCC electrode may come from the fast and stable surface oxygen exchange process in the medium frequency range of the electrochemical impedance spectrum.展开更多
A series of N‐CQDs/Ag2CO3composite crystals(where N‐CQDs=Nitrogen doped carbon quantumdots)were prepared by adding different volumes of a solution of N‐CQDs during Ag2CO3crystalgrowth.Under irradiation from a350‐W...A series of N‐CQDs/Ag2CO3composite crystals(where N‐CQDs=Nitrogen doped carbon quantumdots)were prepared by adding different volumes of a solution of N‐CQDs during Ag2CO3crystalgrowth.Under irradiation from a350‐W Xe lamp light(with optical filter,λ≥420nm),the performanceof N‐CQDs/Ag2CO3in photocatalytic degradation of phenol was evaluated.The as‐preparedsamples were analyzed by XRD,SEM,TEM,BET,element mapping,UV‐vis DRS,FT‐IR,XPS,transientphotocurrent response and EIS testing.The results showed that after coupling with trace amountsof N‐CQDs,both the photocatalytic activity and stability of Ag2CO3were greatly boosted.The additionof N‐CQDs solution influenced the crystallization of Ag2CO3,resulting in a distinct decrease inAg2CO3crystal size and an obvious increase in surface area.Moreover,the charge transfer resistancewas greatly reduced,and the separation efficiency of photogenerated electrons and holes wasstrongly promoted.The presence of NCQDs on the surface of the catalysts facilitates the transfer ofphotogenerated electrons,slowing the photocorrosion rate of Ag2CO3,and then resulting in higherstability than bare Ag2CO3in degradation.The synergistic effect of the improvement of morphologyand charge transfer rate thus accounted for the superior photocatalytic performance ofN‐CQDs/Ag2CO3.展开更多
There has been a continuous need for high active, excellently durable and low-cost electrocatalysts for rechargeable zinc-air batteries. Among many low-cost metal based candidates, transition metal oxides with the CNT...There has been a continuous need for high active, excellently durable and low-cost electrocatalysts for rechargeable zinc-air batteries. Among many low-cost metal based candidates, transition metal oxides with the CNTs composite have gained increasing attention. In this paper, the 3-D hollow sphere MnO_2 nanotube-supported Co_3O_4 nanoparticles and its carbon nanotubes hybrid material(Co_3 O_4/MnO_2-CNTs) have been synthesized via a simple co-precipitation method combined with post-heat treatment. The morphology and composition of the catalysts are thoroughly analyzed through SEM, TEM, TEM-mapping, XRD, EDX and XPS. In comparison with the commercial 20% Pt/C, Co_3O_4/MnO_2,bare MnO_2 nanotubes and CNTs, the hybrid Co_3O_4/MnO_2-CNTs-350 exhibits perfect bi-functional catalytic activity toward oxygen reduction reaction and oxygen evolution reaction under alkaline condition(0.1 M KOH). Therefore, high cell performances are achieved which result in an appropriate open circuit voltage(～1.47 V),a high discharge peak power density(340 mW cm^(-2)) and a large specific capacity(775 mAh g^(-1) at 10 mA cm^(-2)) for the primary Zn-air battery, a small charge-discharge voltage gap and a high cycle-life(504 cycles at 10 mA cm^(-2) with 10 min per cycle) for the rechargeable Zn-air battery. In particular, the simple synthesis method is suitable for a large-scale production of this bifunctional material due to a green, cost effective and readily available process.展开更多
In order to discover novel compounds with high-activity to control aphid,a series of novel（E）-β-farnesene analogues containing 1,2,3-thiadiazole were designed and synthesized,and their structures were confirmed by ...In order to discover novel compounds with high-activity to control aphid,a series of novel（E）-β-farnesene analogues containing 1,2,3-thiadiazole were designed and synthesized,and their structures were confirmed by IR,^1H NMR,^13C NMR,and HRMS（ESI）.The stability of representative compounds was studied by HPLC and -1H NMR techniques.Repellent activity results indicated that compounds 8h and 8j displayed 60.3%and 62.0%repellent rates,respectively.The aphicidal bioassay results showed that most analogues exhibited considerable aphicidal activity against Myzus persicae.Especially,analogues 81,8s and 8t exhibited high activity with LC50 values of 33.4 μg/mL,50.2 μg/mL and 61.8 μg/mL,respectively,which were higher than the lead compound（E）-β-farnesene,but lower than commercial insecticide pymetrozine with a LC50 of 7.1 μg/mL展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFA1602700 and 2022YFB2502104)the National Natural Science Foundation of China(22375089)the Key Research and Development Program of Jiangsu Provincial Department of Science and Technology of China(BE2022332).
文摘Electrocatalyst activity and stability demonstrate a“seesaw”relationship.Introducing vacancies(Vo)enhances the activity by improving reactant affinity and increasing accessible active sites.However,deficient or excessive Vo reduces polysulfide adsorption and lowers catalytic stability.Herein,a novel“heteroatoms synergistic anchoring vacancies”strategy is proposed to address the trade-off between high activity and stability.Phosphorus-doped CoSe_(2)with remained rich selenium vacancies(P-CS-Vo-0.5)was synthesized by producing abundant selenium Vo followed by controlled P atom doping.Atomic-scale microstructure analysis elucidated a dynamic process of surface vacancy generation and the subsequent partial occupation of these vacancies by P atoms.Density functional theory simulations and in situ Raman tests revealed that the Se vacancies provide highly active catalytic sites,accelerating polysulfide conversion,while P incorporation effectively reduces the surface energy of Se vacancies and suppresses their inward migration,enhancing structural robustness.The battery with the optimal P-CS-Vo-0.5 separator delivers an initial discharge capacity of 1306.7 mAh g^(-1)at 0.2C,and maintain 5.04 mAh cm^(-2)at a high sulfur loading(5.7 mg cm^(-2),5.0μL mg^(-1)),achieving 95.1%capacity retention after 80 cycles.This strategy of modifying local atomic environments offers a new route to designing highly active and stable catalysts.
基金supports of this work by KFUPM through the project # R15-CW-11 (MIT-13103, 13104) under the Center of Excellence for Scientific Research Collaboration with MIT and the project # RG 1311
文摘Polymeric-inorganic nanocomposite catalysts were synthesized by facile one-pot chemical polymerization of pyrrole in the presence of titanium dioxide nanoparticles. The electrical, optical, photovoltaic performance of dye sensitized solar cell（DSSC） and visible light driven photocatalytic activities of the nanocomposite were investigated. The prepared nanocomposite displays excellent photo-activity, attaining 100% degradation of methyl orange dye in 60 min under visible light source while 55% for pure TiO_2 under similar experimental conditions. The photovoltaic performance of the polypyrrole-titanium dioxide（PPy-TiO_2） nanocomposite has a 51.4% improvement with a photo-conversion efficiency of 8.07% as compared to pure TiO_2 based DSSC. By comparing the physical mixture of the PPy-TiO_2 nanocomposite and pristine TiO_2, the enhanced activity of the PPy-TiO_2 nanocomposite can be attributed to the reduced charge transfer resistance, outstanding electrical conductance of the PPy, the nano-sized structure of TiO_2 and their synergetic effect. Furthermore, the PPy-TiO_2 nanocomposite shows excellent electrical conductivity and isothermal stability under ambient conditions below 110？C.
基金financially supported by the National Natural Science Foundation of China(Nos.52174283 and 52274308)。
文摘Cobalt-based phosphides show excellent hydrogen evolution reaction(HER)performance,however,improving the intrinsic activity and stability of it in alkaline electrolyte still remains a challenge.Herein,CoRuOH/Co_(2)P/CF with heterojunction structure was developed by means of molten salt and rapid hydrolysis(30 s).The OH-from rapid surface hydrolysis of Co_(2)P as a hydrogen adsorption site can facilitate the formation of thin CoRuOH layer as a water dissociation site,which may bring out better synergistic effect for alkaline HER.Moreover,the covering of CoRuOH can improve the stability of Co_(2)P for HER.When drives at 100 mA/cm^(2),it only requires overpotential of 81 mV in 1.0 mol/L KOH(25℃).Even at higher current density(1000 mA/cm^(2)),CoRuOH/Co_(2)P/CF can also operate stability for at least 100 h.When coupling with NiFe-LDH/IF in a two-electrode system,the voltage of NiFe-LDH/IF(+)||CoRuOH/Co_(2)P/CF(-)at 1000 mA/cm^(2)is merely 1.77 V with 100 h,demonstrating great potential for water splitting.The implementation of this work provides a new strategy and reference for the further improvement of transition metal phosphides as HER electrocatalysts.
基金Supported by the National Basic Research Program of China under Grant Nos 2010CB327504,2011CB922100 and2011CB301900the National Natural Science Foundation of China under Grant Nos 11104130 and 61322112+2 种基金the Natural Science Foundation of Jiangsu Province under Grant Nos BK2011556 and BK2011050the Priority Academic Program Development of Jiangsu Higher Education Institutionsand the NUPTSF Grant Nos NY213069 and NY214028
文摘The effect of oxygen partial pressure （Po2） during the channel layer deposition on bias stability of amorphous indium-gallium-zinc oxide （a-IGZO） thin film transistors （TFTs） is investigated. As Po2 increases from 10% to 30%, it is found that the device shows enhanced bias stress stability with significantly reduced threshold voltage drift under positive gate bias stress. Based on the x-ray photoelectron spectroscopy measurement, the concentration of oxygen vacancies （Or） within the a-IGZO layer is suppressed by increasing Po2. Meanwhile, the low-frequency noise analysis indicates that the average trap density near the channel/dielectric interface continuously drops with increasing Po2. Therefore, the improved interface quality with increasing Po2 during the channel layer deposition can be attributed to the reduction of interface Ov-related defects, which agrees with the enhanced bias stress stability of the a-IGZO TFTs.
文摘The temperature stability of supercapacitor（SC） is largely determined by the properties of the electrolyte.Hydrogel electrolytes（HGE）, due to their hydrophilic polymer skeleton, show different temperature stability to that of liquid aqueous electrolytes. In this study, symmetric activated carbon（AC） SCs had been assembled with in situ electrodeposited poly（vinyl alcohol） potassium borate（PVAPB） HGE. The electrochemical performance of the SCs was systematically studied at different temperatures. Results show that the conductivity of PVAPB HGE is comparable with that of liquid aqueous electrolytes at different temperatures. The operating temperature range of PVAPB HGE SCs is -5–60°C, while those of the 1 mol/L Na2SO4SCs and the 0.9 mol/L KClSCs are 20–80°C and 20–40°C, respectively. The specific capacitance of PVAPB HGE SC is higher than those of SCs using liquid aqueous electrolytes at any temperature. The excellent temperature stability of PVAPB HGE makes it possible to build stable aqueous SCs in the wider temperature range.
基金supported by the National Railway Group Science and Technology Program(Nos.N2020J026 and N2021J028)the Independent Research and Development Projects of Traction Power State Key Laboratory(No.2022TPL-T02),China。
文摘This paper puts forward a high-speed train bogie active stability method,based on frame lateral vibration control,for improving the stability and critical speed of railway vehicles at high speeds.Two inertial actuators apply active control forces to the front and rear end beams of the bogie frame.A scale model of bogie lateral dynamics is established,as well as the state space equation of the control system.Also,the multi-objective optimization is used to construct state feedback parameters,which take hunting stability and control effort into account.Furthermore,the effects of time-delay in the control system and suspension parameters on bogie hunting stability are studied.The dynamic behaviors and the stability mechanism of the bogie control system are analyzed.Finally,a 1:5 scale test rig is used to conduct a bogie active stability experiment.The results reveal that active control of frame lateral vibration can effectively improve the bogie system's hunting stability margin at high speeds,but time-delay in the control system cannot be ignored.
文摘The presynaptic active zone is a dynamic structure that orchestrates regulated release of neurotrans- mitters. Developmental and aging processes, and changes in neuronal network activity can all modulate the number, size and composition of active zone and thereby synaptic efficacy. However, very little is known about the mechanism that controls the structural stability of active zone. By study- ing a model synapse, the Drosophila neuromuscular iunction, our recent work shed light on how two scaffolding proteins at the active zone regulate active zone stability by promoting a localized dephos- phorylation event at the nerve terminal. Here we discuss the major insights from our findings and their implications for future research.
基金supported by grants from the National Natural Science Foundation of China (No.81571987 and 81371820)the Ph.D. Candidate Research Innovation Fund of Nankai University (2015) (No.68150003)
文摘The multifunctional trans-activator Tat is an essential regulatory protein for HIV-1 replication and is characterized by high sequence diversity. Numerous experimental studies have examined Tat in HIV-1 subtype B, but research on subtype C Tat is lacking, despite the high prevalence of infections caused by subtype C worldwide. We hypothesized that amino acid differences contribute to functional differences among Tat proteins. In the present study, we found that subtype B NL4-3Tat and subtype C isolate HIV1084 i Tat exhibited differences in stability by overexpressing the fusion protein Tat-Flag. In addition, 1084 i Tat can activate LTR and NF-κB more efficiently than NL4-3 Tat. In analyses of the activities of the truncated forms of Tat, we found that the carboxylterminal region of Tat regulates its stability and transactivity. According to our results, we speculated that the differences in stability between B-Tat and C-Tat result in differences in transactivation ability.
基金Project supported by the National Natural Science Foundation of China(Grant No.61701349)the Natural Science Foundation of Shandong Province,China(Grant Nos.ZR2017QF012 and ZR2017MF042)the Program for the Top Young Innovative Talents,China(Grant No.Q1313-03)
文摘Active metamaterials incorporating with non-Foster elements have been considered as one of the means of overcoming inherent limitations of the passive counterparts, thus achieving broadband or gain metamaterials. However, realistic active metamaterials, especially non-Foster loaded medium, would face the challenge of the possibility of instability. Moreover,they normally appear to be time-variant and in unsteady states, which leads to the necessity of a stability method to cope with the stability issue considering the system model uncertainty. In this paper, we propose an immittance-based stability method to design a non-Foster loaded metamaterial ensuring robust stability. First, the principle of this stability method is introduced after comparing different stability criteria. Based on the equivalent system model, the stability characterization is used to give the design specifications to achieve an active metamaterial with robust stability. Finally, it is applied to the practical design of active metamaterial with non-Foster loaded loop arrays. By introducing the disturbance into the nonFoster circuit（NFC）, the worst-case model uncertainty is considered during the design, and the reliability of our proposed method is verified. This method can also be applied to other realistic design of active metamaterials.
基金supported by the Youth Innovation Promotion Association(no.2015147)CAS and National Program on Key Basic Research Project(973 Program,2012CB215500)+1 种基金the Outstanding Youngest Scientist FoundationChinese Academy of Sciences(CAS)
文摘Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness of OER and the high prices as well as the scarcity of the most active precious metal electrocatalysts are the major bottleneck in these devices. Developing low-cost non-precious metal catalysts with high activity and stability for OER is highly desirable. A facile, in situ template method combining the dodecyl benzene sulfuric acid sodium（SDBS） assisted hydrothermal process with subsequent high-temperature treatment was developed to prepare porous Co3O4 with improved surface area and hierarchical porous structure as precious catalysts alternative for oxygen evolution reaction（OER）. Due to the unique structure, the as-prepared catalyst shows higher electrocatalytic activity than Co3O4 prepared by traditional thermal-decomposition method（noted as Co3O4-T） and commercial IrO2 catalyst for OER in 0.1M KOH aqueous solution. Moreover, it displays improved stability than Co3O4-T. The results demonstrate a highly efficient, scalable, and low cost method for developing highly active and stable OER electrocatalysts in alkaline solutions.
基金financially supported by the National Natural Science Foundation of China(41871064)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0304)。
文摘The Qinghai-Tibet Plateau(QTP)distributes the largest extent of high-altitude mountain permafrost in the world(Zou et al.,2017),which has different characteristics from high-latitude permafrost(Yang et al.,2010)and stores massive soil carbon.
文摘After publication of the research article "Constructing inter diffusive PtCuNi/WOg interface to enhance the catalytic activity and stability in oxygen reduction"(https://doi.org/10.1007/s42864-023-00226-0).The authors discovered that the"Acknowledgement"is missing from the published online version,due to the unintentional mistake when preparing the manuscript.This could be unfair to the entities/scholars providing meaningful help to this work,as well as the funding agency that provided the financial support to this work.Therefore,an erratum is requested by the authors to acknowledge the following parties.
基金financially supported by the Shenzhen Science and Technology Innovation Program(Grant No.JCYJ20220530150011024)。
文摘A comprehensive understanding of the dynamic processes at the catalyst/electrolyte interfaces is crucial for the development of advanced electrocatalysts for the oxygen evolution reaction(OER).However,the chemical processes related to surface corrosion and catalyst degradation have not been well understood so far.In this study,we employ LiCoO_(2) as a model catalyst and observe distinct OER activities and surface stabilities in different alkaline solutions.Operando X-ray diffraction(XRD)and online mass spectroscopy(OMS)measurements prove the selective intercalation of alkali cations into the layered structure of LiCoO_(2) during OER.It is proposed that the dynamic cation intercalations facilitate the chemical oxidation process between highly oxidative Co species and adsorbed water molecules,triggering the so-called electrochemical-chemical reaction mechanism(EC-mechanism).The results of this study emphasize the influence of cations on OER and provide insights into new strategies for achieving both high activity and stability in high-performance OER catalysts.
基金financially supported by the Natural Science Foundation of Hunan Province(2023JJ40608,2024JJ6413)the Majoy Project of the Education Department of Hunan Province(24A0610).
文摘Proton exchange membrane water electrolysis(PEMWE)technology is widely recognized as a cornerstone for green hydrogen production,offering high operational current densities exceeding 1.0 A cm^(-2),rapid dynamic response capabilities,and zero-carbon emission characteristics[1].However,the sluggish kinetics of oxygen evolution reaction(OER)at the anode presents a critical bottleneck for large-scale commercial deployment(Fig.1(a)).Despite significant advancements through electronic structure modulation[2]and coordination environment optimization[3],the deprotonation energy barrier of oxygen-containing intermediates and the stability of active sites under acidic conditions remain unresolved challenges.
基金the Iranian Nano Technology Initiative Council and the Petroleum University of Technology for financial support
文摘The performance of the two newly developed bimetallic catalysts based on the precursor, Mo/Al_2O_3, was compared for reverse water gas shift(RWGS) reaction. The structures of the precursor and the catalysts were studied using X-ray diffraction(XRD), Brunauer–Emmett–Teller(BET) analysis, inductively coupled plasma-atomic emission spectrometry(ICP-AES), CO chemisorption, temperature programmed reduction of hydrogen(H_2-TPR) and scanning electron microscopy(SEM) techniques. The activity of Fe-Mo and Co-Mo catalysts was compared in a fixed bed reactor at different temperatures. It is shown that the Co-Mo catalyst has higher CO_2 conversion at all temperature level. The time-on-stream(TOS) analysis of the activity of catalysts for the RWGS reaction was carried out over a continuous period of 60h for both catalysts. The Fe-Mo/Al_2O_3 catalyst exhibits good stability within a period of 60h, however, the Co-Mo/Al_2O_3 is gradually deactivated after 50h of reaction time. Existence of(Fe_2(MoO4_))_3 phase in Fe-Mo/Al_2O_3 catalyst makes this catalyst more stable for RWGS reaction.
文摘The tumor suppressor p53 is a multifunctional, highly regulated, and promoter-specific transcriptional factor that is uniquely sensitive to DNA damage and cellular stress signaling. The mechanisms by which p53 directs a damaged cell down either a cell growth arrest or an apoptotic pathway remain poorly understood. Evidence suggests that the in vivo functions of p53 seem to balance the cell-fate choice with the type and severity of damage that occurs. The concept of antirepression, or inhibition of factors that normally keep p53 at bay, may help explain the physiological mechanisms for p53 activation. These factors also provide novel chemotherapeutic targets for the reactivation of p53 in tumors harboring a wild-type copy of the gene.
基金Natural Science Foundation of Guangdong Province,Grant/Award Number:2021A1515010395Fundamental Research Funds for the Central Universities,Grant/Award Number:2022ZYGXZR002+2 种基金National Natural Science Foundation of China,Grant/Award Numbers:22179039,22005105Pearl River Talent Recruitment Program,Grant/Award Number:2019QN01C693Guangdong Innovative and Entrepreneurial Research Team Program,Grant/Award Number:2021ZT09L392。
文摘While double perovskites of PrBaCo_(2)O_(6)(PBC)have been extensively developed as the cathodes for proton-conducting solid oxide fuel cells(H-SOFCs),the effects of Sr-or Ca-doping at the A site on the activity and stability of the oxygen reduction reaction are yet to be fully studied.Here,the effect of A-site doping on the oxygen reduction reaction activity and stability has been studied by evaluating the performance of both symmetrical and single cells.It is shown that Ca-doped PBC(PrBa_(0.8)Ca_(0.2)Co_(2)O_(6),PBCC)shows a slightly smaller polarization resistance(0.076Ωcm^(2))than that(0.085Ωcm^(2))of Sr-doped PBC(PrBa0.8Sr0.2Co2O6,PBSC)at 700◦C in wet air.Moreover,the degradation rate of PBCC is 0.0003Ωcm^(2)h^(−1)(0.3%h−1)in 100 h,about 1/10 of that of PBSC at 700◦C in wet air.In addition,it is also confirmed that single cells with PBCC cathode show higher peak power density(1.22Wcm^(−2)vs.1.08Wcm^(−2)at 650◦C)and better durability(degradation rate of 0.1%h^(−1)vs.0.13%h^(−1))than those with PBSC cathode.The distribution of relaxation time analyses suggests that the better stability of the PBCC electrode may come from the fast and stable surface oxygen exchange process in the medium frequency range of the electrochemical impedance spectrum.
基金supported by the National Natural Science Foundation of China(21567008,21607064,21707055)Program of Qingjiang Excellent Young Talents,Jiangxi University of Science and Technology+2 种基金Program of 5511 Talents in Scientific and Technological Innovation of Jiangxi Province(20165BCB18014)Academic and Technical Leaders of the Main Disciplines in Jiangxi Province(20172BCB22018)Jiangxi Province Natural Science Foundation(20161BAB203090)~~
文摘A series of N‐CQDs/Ag2CO3composite crystals(where N‐CQDs=Nitrogen doped carbon quantumdots)were prepared by adding different volumes of a solution of N‐CQDs during Ag2CO3crystalgrowth.Under irradiation from a350‐W Xe lamp light(with optical filter,λ≥420nm),the performanceof N‐CQDs/Ag2CO3in photocatalytic degradation of phenol was evaluated.The as‐preparedsamples were analyzed by XRD,SEM,TEM,BET,element mapping,UV‐vis DRS,FT‐IR,XPS,transientphotocurrent response and EIS testing.The results showed that after coupling with trace amountsof N‐CQDs,both the photocatalytic activity and stability of Ag2CO3were greatly boosted.The additionof N‐CQDs solution influenced the crystallization of Ag2CO3,resulting in a distinct decrease inAg2CO3crystal size and an obvious increase in surface area.Moreover,the charge transfer resistancewas greatly reduced,and the separation efficiency of photogenerated electrons and holes wasstrongly promoted.The presence of NCQDs on the surface of the catalysts facilitates the transfer ofphotogenerated electrons,slowing the photocorrosion rate of Ag2CO3,and then resulting in higherstability than bare Ag2CO3in degradation.The synergistic effect of the improvement of morphologyand charge transfer rate thus accounted for the superior photocatalytic performance ofN‐CQDs/Ag2CO3.
基金financial support from the National Natural Science Foundation of China (U1510120, 91645110)the Project of Introducing Overseas Intelligence High Education of China (2017-2018)+1 种基金the Graduate Thesis Innovation Foundation of Donghua University (EG2016034)the College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University
文摘There has been a continuous need for high active, excellently durable and low-cost electrocatalysts for rechargeable zinc-air batteries. Among many low-cost metal based candidates, transition metal oxides with the CNTs composite have gained increasing attention. In this paper, the 3-D hollow sphere MnO_2 nanotube-supported Co_3O_4 nanoparticles and its carbon nanotubes hybrid material(Co_3 O_4/MnO_2-CNTs) have been synthesized via a simple co-precipitation method combined with post-heat treatment. The morphology and composition of the catalysts are thoroughly analyzed through SEM, TEM, TEM-mapping, XRD, EDX and XPS. In comparison with the commercial 20% Pt/C, Co_3O_4/MnO_2,bare MnO_2 nanotubes and CNTs, the hybrid Co_3O_4/MnO_2-CNTs-350 exhibits perfect bi-functional catalytic activity toward oxygen reduction reaction and oxygen evolution reaction under alkaline condition(0.1 M KOH). Therefore, high cell performances are achieved which result in an appropriate open circuit voltage(～1.47 V),a high discharge peak power density(340 mW cm^(-2)) and a large specific capacity(775 mAh g^(-1) at 10 mA cm^(-2)) for the primary Zn-air battery, a small charge-discharge voltage gap and a high cycle-life(504 cycles at 10 mA cm^(-2) with 10 min per cycle) for the rechargeable Zn-air battery. In particular, the simple synthesis method is suitable for a large-scale production of this bifunctional material due to a green, cost effective and readily available process.
基金the financial support from the National Natural Science Foundation of China (No. 21132003)
文摘In order to discover novel compounds with high-activity to control aphid,a series of novel（E）-β-farnesene analogues containing 1,2,3-thiadiazole were designed and synthesized,and their structures were confirmed by IR,^1H NMR,^13C NMR,and HRMS（ESI）.The stability of representative compounds was studied by HPLC and -1H NMR techniques.Repellent activity results indicated that compounds 8h and 8j displayed 60.3%and 62.0%repellent rates,respectively.The aphicidal bioassay results showed that most analogues exhibited considerable aphicidal activity against Myzus persicae.Especially,analogues 81,8s and 8t exhibited high activity with LC50 values of 33.4 μg/mL,50.2 μg/mL and 61.8 μg/mL,respectively,which were higher than the lead compound（E）-β-farnesene,but lower than commercial insecticide pymetrozine with a LC50 of 7.1 μg/mL
