The printed circuit heat exchanger(PCHE) is receiving wide attention as a new kind of compact heat exchanger and is considered as a promising vaporizer in the LNG process. In this paper, a PCHE straight channel in the...The printed circuit heat exchanger(PCHE) is receiving wide attention as a new kind of compact heat exchanger and is considered as a promising vaporizer in the LNG process. In this paper, a PCHE straight channel in the length of 500 mm is established, with a semicircular cross section in a diameter of 1.2 mm.Numerical simulation is employed to investigate the flow and heat transfer performance of supercritical methane in the channel. The pseudo-boiling theory is adopted and the liquid-like, two-phase-like, and vapor-like regimes are divided for supercritical methane to analyze the heat transfer and flow features.The results are presented in micro segment to show the local convective heat transfer coefficient and pressure drop. It shows that the convective heat transfer coefficient in segments along the channel has a significant peak feature near the pseudo-critical point and a heat transfer deterioration when the average fluid temperature in the segment is higher than the pseudo-critical point. The reason is explained with the generation of vapor-like film near the channel wall that the peak feature related to a nucleateboiling-like state and heat transfer deterioration related to a film-boiling-like state. The effects of parameters, including mass flow rate, pressure, and wall heat flux on flow and heat transfer were analyzed.In calculating of the averaged heat transfer coefficient of the whole channel, the traditional method shows significant deviation and the micro segment weighted average method is adopted. The pressure drop can mainly be affected by the mass flux and pressure and little affected by the wall heat flux. The peak of the convective heat transfer coefficient can only form at high mass flux, low wall heat flux, and near critical pressure, in which condition the nucleate-boiling-like state is easier to appear. Moreover,heat transfer deterioration will always appear, since the supercritical flow will finally develop into a filmboiling-like state. So heat transfer deterioration should be taken seriously in the design and safe operation of vaporizer PCHE. The study of this work clarified the local heat transfer and flow feature of supercritical methane in microchannel and contributed to the deep understanding of supercritical methane flow of the vaporization process in PCHE.展开更多
Global warming and frequent extreme drought events lead to tree death and extensive forest decline,but the underlying mechanism is not clear.In drought years,cambial development is more sensitive to climate change,but...Global warming and frequent extreme drought events lead to tree death and extensive forest decline,but the underlying mechanism is not clear.In drought years,cambial development is more sensitive to climate change,but in different phenological stages,the response rela-tionship is nonlinear.Therefore,the dynamic relationship between tree radial growth and climatic/environmental fac-tors needs to be studied.We thus continuously monitored radial growth of Qinghai spruce(Picea crassifolia Kom.)and environmental factors from January 2021 to November 2022 using point dendrometers and portable meteorological weather stations in the central area of the Qilian Mountains.The relationship and stability between the radial growth of Qinghai spruce and environmental factors were compared for different levels of drought in 2021 and 2022.The year 2022 had higher temperatures and less precipitation and was drier than 2021.Compared with 2021,the growing period in 2022 for Qinghai spruce was 10 days shorter,maximum growth rate(Grmax)was 4.5μm·d^(-1) slower,and the initiation of growth was 6 days later.Growth of Qinghai spruce was always restricted by drought,and the stem radial increment(SRI)was more sensitive to precipitation and air relative humidity.Seasonal changes in cumulative radial growth were divided into four phenological stages according to the time of growth onset,cessation,and maximum growth rate(Grmax)of Qinghai spruce.Stability responses of SRI to climate change were stronger in Stage 3 and Stage 4 of 2021 and stronger in Stage 1(initiation growth stage)and Stage 3 of 2022.The results provide important information on the growth of the trees in response to drought and for specific managing forests as the climate warms.展开更多
The spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode active materials(CAMs)are considered a promising alternative to commercially available cathodes such as layered and polyanion oxide cathodes,primarily due to their notab...The spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode active materials(CAMs)are considered a promising alternative to commercially available cathodes such as layered and polyanion oxide cathodes,primarily due to their notable safety and high energy density,particularly in their single-crystal type.Nevertheless,the industrial application of the LNMO CAMs is severely inhibited due to the interfacial deterioration and corrosion under proton-rich and high-voltage conditions.This study successfully designed and synthesized two typical types of crystal facets-exposed single-crystal LNMO CAMs.By tracking the electrochemical deterioration and chemical corrosion evolution,this study elucidates the surface degradation mechanisms and intrinsic instability of the LNMO,contingent upon their crystal facets.The(111)facet,due to its elevated surface energy,is found to be more susceptible to external attack compared to the(100)and(110)facets.Our study highlights the electrochemical corrosion stability of crystal plane engineering for spinel LNMO CAMs.展开更多
Boron phosphide(BP)has gained significant research attention due to its unique photoelectric and mechanical properties.In this work,we investigated the stability of BP under high pressure using x-ray diffraction and s...Boron phosphide(BP)has gained significant research attention due to its unique photoelectric and mechanical properties.In this work,we investigated the stability of BP under high pressure using x-ray diffraction and scanning electron microscope.The phase diagram of BP was explored in both B-rich and P-rich environments,revealing crucial insight into its behavior at 5.0 GPa.Additionally,we measured the melting curve of BP from 8.0 GPa to 15.0 GPa.Our findings indicate that the stability of BP under high pressure is improved within B-rich and P-rich environments.Furthermore,we report a remarkable observation of melting curve frustration at 10.0 GPa.This study will enhance our understanding of stability of BP under high pressure,shedding light on its potential application in semiconductor,thermal,and light-transmitting devices.展开更多
Sodium-based storage devices based on conversion-type metal sulfide anodes have attracted great atten-tion due to their multivalent ion redox reaction ability.However,they also suffer from sodium polysul-fides(NaPSs)s...Sodium-based storage devices based on conversion-type metal sulfide anodes have attracted great atten-tion due to their multivalent ion redox reaction ability.However,they also suffer from sodium polysul-fides(NaPSs)shuttling problems during the sluggish Na^(+) redox process,leading to"voltage failure"and rapid capacity decay.Herein,a metal cobalt-doping vanadium disulfide(Co-VS_(2))is proposed to simulta-neously accelerate the electrochemical reaction of VS_(2) and enhance the bidirectional redox of soluble NaPSs.It is found that the strong adsorption of NaPSs by V-Co alloy nanoparticles formed in situ during the conversion reaction of Co-VS_(2) can effectively inhibit the dissolution and shuttle of NaPSs,and ther-modynamically reduce the formation energy barrier of the reaction path to effectively drive the complete conversion reaction,while the metal transition of Co elements enhances reconversion kinetics to achieve high reversibility.Moreover,Co-VS_(2) also produce abundant sulfur vacancies and unsaturated sulfur edge defects,significantly improve ionic/electron diffusion kinetics.Therefore,the Co-VS_(2) anode exhibits ultrahigh rate capability(562 mA h g^(-1) at 5 A g^(-1)),high initial coulombic efficiency(~90%)and 12,000 ultralong cycle life with capacity retention of 90%in sodium-ion batteries(SIBs),as well as impressive energy/power density(118 Wh kg^(-1)/31,250 W kg^(-1))and over 10.000 stable cycles in sodium-ion hybrid capacitors(SIHCs).Moreover,the pouch cell-type SIHC displays a high-energy density of 102 Wh kg^(-1) and exceed 600 stable cycles.This work deepens the understanding of the electrochemical reaction mechanism of conversion-type metal sulfide anodes and provides a valuable solution to the shuttlingofNaPSs inSIBsandSIHCs.展开更多
The stacking and aggregation of graphene nanosheets have been obstacles to their application as electrode materials for microelectronic devices.This study deploys a one-step,scalable,facile electrochemical exfoliation...The stacking and aggregation of graphene nanosheets have been obstacles to their application as electrode materials for microelectronic devices.This study deploys a one-step,scalable,facile electrochemical exfoliation technique to fabricate nitrogen(N)and chlorine(Cl)co-doped graphene nanosheets(i.e.,N-Cl-G)via the application of constant voltage on graphite in a mixture of 0.1 mol/L H_(2)SO_(4)and 0.1 mol/L NH_(4)Cl without using dangerous and exhaustive operation.The introduction of Cl(with its large radius)and N,both with high electrical negativity,facilitates the modulation of the electronic structure of graphene and creation of rich structural defects in it.Consequently,in the as-constructed supercapacitors,N-Cl-G exhibits a high specific capacitance of 77 F/g at 0.2 A/g and remarkable cycling stability with 91.7%retention of initial capacitance after 20,000 cycles at 10 A/g.Furthermore,a symmetrical supercapacitor assembled with N-Cl-G as the positive and negative electrodes(denoted as N-Cl-G//N-Cl-G)exhibits an energy density of 3.38 Wh/kg at a power density of 600 W/kg and superior cycling stability with almost no capacitance loss after 5000 cycles at 5 A/g.This study provides a scalable protocol for the facile fabrication of high-performance co-doped graphene as an electrode material candidate for supercapacitors.展开更多
As we are facing an aging society,anti-aging strategies have been pursued to reduce the negative impacts of aging and increase the health span of human beings.Gut microbiota has become a key factor in the anti-aging p...As we are facing an aging society,anti-aging strategies have been pursued to reduce the negative impacts of aging and increase the health span of human beings.Gut microbiota has become a key factor in the anti-aging process.Modulation of gut microbiota by fecal microbiota transplantation(FMT)to prevent frailty and unhealthy aging has been a hot topic of research.This narrative review summarizes the benefits of FMT for health span and lifespan,brains,eyes,productive systems,bones,and others.The mechanisms of FMT in improving healthy aging are discussed.The increased beneficial bacteria and decreased pathological bacteria decreased gut permeability and systemic inflammation,increased short-chain fatty acid(SCFA)and SCFA-producing bacteria,and other factors are listed as mechanisms of FMT to improve healthy aging.The points that need to be considered to ensure the optimal outcomes of FMT are also discussed,such as recipients’age,sex,genetic background,and gut microbiota after FMT.Although thisfield is still in its infancy,it has shown that FMT has great potential to improve healthy aging.展开更多
Recent studies have highlighted the potential of plant extracts as therapeutic agents for managing oxidative stress and related disorders.This study aims to elucidate the phenolic composition and antioxidant propertie...Recent studies have highlighted the potential of plant extracts as therapeutic agents for managing oxidative stress and related disorders.This study aims to elucidate the phenolic composition and antioxidant properties of Gymnema sylvestre extracts.Ethanolic reflux extraction followed by column chromatography was employed to isolate phenolic compounds.The total phenolic and flavonoid contents were quantified using the Folin–Ciocalteu and aluminum chloride colorimetric methods,respectively.Antioxidant activities were assessed by DPPH,ABTS scavenging assays and the ferric reducing antioxidant power(FRAP)assay.High-Performance Liquid Chromatography(HPLC)with a C18 column and Thermo TSQ Quantum Access Max(LC-MS)were used to determine the levels of gymnemic acid and identify other potential phenolic compounds.The analysis revealed significant antioxidant activities in the fractions.Fraction A showed the highest DPPH and ABTS scavenging activities,and Fraction C demonstrated the highest ferric reducing power.LC-MS analysis identified several phenolic compounds,indicating that these are major contributors to the antioxidant efficacy of the extract.This study provides a detailed phenolic profile and confirms the strong antioxidant potential of Gymnema sylvestre leaf extract,supporting its therapeutic use and further investigation.展开更多
Objective:To explore the effects of acupuncture and tuina combined with rehabilitation therapy on oxidative stress response and motor function in stroke hemiplegia patients.Methods:Sixty stroke hemiplegia patients wer...Objective:To explore the effects of acupuncture and tuina combined with rehabilitation therapy on oxidative stress response and motor function in stroke hemiplegia patients.Methods:Sixty stroke hemiplegia patients were randomly divided into observation and control groups,with 30 cases each.The control group received conventional rehabilitation therapy,while the observation group also underwent acupuncture and tuina.After 8 weeks of treatment,oxidative stress indicators[malondialdehyde(MDA),superoxide dismutase(SOD),glutathione peroxidase(GSH-Px)],neurological deficit scores(NIHSS),Fugl-Meyer motor function scores(FMA),and activities of daily living(Barthel Index)were compared between the two groups.Results:Before treatment,there were no significant differences in MDA,NIHSS scores,FMA scores,and Barthel Index between the two groups(P>0.05).After 8 weeks,the observation group had lower MDA and NIHSS scores,but higher SOD,GSH-Px,FMA scores,and Barthel Index compared to the control group,with statistically significant differences(P<0.05).Conclusion:Acupuncture and tuina combined with rehabilitation therapy can effectively improve oxidative stress levels,promote neurological recovery,enhance motor function,and improve daily living activities in stroke hemiplegia patients.This combined therapy is recommended for clinical application.展开更多
English is an important course in colleges,and students’proficiency in the language can significantly affect their learning in multiple disciplines.At present,offline classroom teaching is still the primary mode of c...English is an important course in colleges,and students’proficiency in the language can significantly affect their learning in multiple disciplines.At present,offline classroom teaching is still the primary mode of college English teaching,and online teaching has not been widely used.Under the background of new liberal arts,the teaching tasks and objectives of college English have changed,and it is imperative to carry out online-offline hybrid teaching mode.This paper analyzes the feasibility of the online-offline hybrid teaching mode of college English,summarizes its problems,and explores its implementation strategies in the context of the new liberal arts,to provide references for teachers.展开更多
针对传统比例-积分-微分(proportional integral derivative,PID)控制和模型论控制方法难以应对新型电力系统背景下微电网面临的运行场景复杂多变的问题,提出了基于模糊神经网络的微电网荷储协调智能控制方法。首先确定了微电网模糊控...针对传统比例-积分-微分(proportional integral derivative,PID)控制和模型论控制方法难以应对新型电力系统背景下微电网面临的运行场景复杂多变的问题,提出了基于模糊神经网络的微电网荷储协调智能控制方法。首先确定了微电网模糊控制输入及输出变量,以平抑净负荷波动及减少储能充放电频次为目的,将微电网控制经验总结成模糊规则表,采用神经网络深度学习算法修正模糊控制模型的隶属度函数中心、宽度和输出权重来提高模型的自适应能力,从而制定了可调控负荷和储能的功率控制系数;进而针对模糊神经网络控制输出的负荷调控需求量在各可调控负荷间分配的问题,提出了基于灵活性供给指标排序的负荷调控优先级选择方法,最终完成了微电网系统储能单元和可调控负荷控制策略的制定。某典型微电网系统算例仿真结果表明,所提方法制定的各可调控负荷与储能控制策略能在避免储能频繁和过度充放电的同时,在并网状态下有效减弱并网功率对上级电网造成的随机扰动,在孤岛状态下能够有效平抑系统功率波动,提升系统运行稳定性。展开更多
Climate exerts a dominant control over the distribution of species.Generally,species migrate to higher elevations to track thermal niches,but variations in morphological traits can result in trait-specific responses t...Climate exerts a dominant control over the distribution of species.Generally,species migrate to higher elevations to track thermal niches,but variations in morphological traits can result in trait-specific responses to climate change.Here we attempted to explore how three sympatrically distributed raptor species(the Upland Buzzard Buteo hemilasius,UB;the Common Kestrel,also called Eurasian Kestrel Falco tinnunculus,EK;and the Saker Falcon Falco cherrug,SF)would respond to climate change over time,and whether their responses would bias by different morphology.We tested the alternative hypotheses for Allen’s rule for UB,EK,and SF in Qinghai Province,China,by modeling their current and future habitat suitability and confirming whether a consistent pattern exists between climate-induced range shifts and morphological differences among species.The extent of the projected distribution range within protected areas was also calculated for each species.We identified the future downward elevation shift for all the species,but with the notable northeastward shifting of the suitable climate space for UB and SF.Climate change would induce range contraction in the future,and the most acute influence is always the result of the pessimistic SSP585 scenario.No obvious pattern in climate-induced range shift was found for EK,for whom the morphological traits were significantly smaller all the time.More seriously,the ratios of highly suitable habitats being protected for our three raptor species were almost at a deficient level(below 1%).This study firstly tested the alternative hypothesis of Allen’s rule among raptors in Qinghai Province unprecedently,confirmed the morphological basis for different responses to changing climate across species,and demonstrated the protection deficiency under the current protected area design.We advocate more related studies in the future to verify our findings across more taxa.展开更多
Objective Cardiac fibroblasts(CFs)proliferation and extracellular matrix deposition are important features of cardiac fibrosis.Various studies have indicated that vitamin D displays an anti-fibrotic property in chroni...Objective Cardiac fibroblasts(CFs)proliferation and extracellular matrix deposition are important features of cardiac fibrosis.Various studies have indicated that vitamin D displays an anti-fibrotic property in chronic heart diseases.This study explored the role of vitamin D in the growth of CFs via an integrin signaling pathway.Methods MTT and 5-ethynyl-2′-deoxyuridine assays were performed to determine cell viability.Western blotting was performed to detect the expression of proliferating cell nuclear antigen(PCNA)and integrin signaling pathway.The fibronectin was observed by ELISA.Immunohistochemical staining was employed to evaluate the expression of integrinβ3.Results The PCNA expression in the CFs was enhanced after isoproterenol(ISO)stimulation accompanied by an elevated expression of integrin beta-3(β3).The blockade of the integrinβ3 with a specific integrinβ3 antibody reduced the PCNA expression induced by the ISO.Decreasing the integrinβ3 by siRNA reduced the ISO-triggered phosphorylation of FAK and Akt.Both the FAK inhibitor and Akt inhibitor suppressed the PCNA expression induced by the ISO in the CFs.Calcitriol(CAL),an active form of vitamin D,attenuated the ISO-induced CFs proliferation by downregulating the integrinβ3 expression,and phosphorylation of FAK and Akt.Moreover,CAL reduced the increased levels of fibronectin and hydroxyproline in the CFs culture medium triggered by the ISO.The administration of calcitriol decreased the integrinβ3 expression in the ISO-induced myocardial injury model.Conclusion These findings revealed a novel role for CAL in suppressing the CFs growth by the downregulation of the integrinβ3/FAK/Akt pathway.展开更多
Developing efficient,low-cost non-noble metal-based bifunctional catalysts to achieve excellent hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)kinetics in alkaline media is challenging but very mean...Developing efficient,low-cost non-noble metal-based bifunctional catalysts to achieve excellent hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)kinetics in alkaline media is challenging but very meaningful.However,improving the electronic structure of the catalyst to optimize the adsorption of intermediates and reduce the reaction energy barrier is the key to improve the reaction efficiency.Herein,a V-doped Co_(2)P coupled with high-entropy MXene heterostructure catalyst(V-Co_(2)P@HE)was prepared by a two-step electrodeposition and controlled phosphorization process.The analyses of X-ray absorption spectroscopy,X-ray photoelectron spectroscopy and theoretical calculations jointly show that the introduction of V and the strong electron coupling between the two components optimize the adsorption energy of water molecules and reaction intermediates.Benefiting from the abundant active sites and optimizing intermediate adsorption energy and heterogeneous interface electronic structure,V-Co_(2)P@HE has excellent HER and OER activity and long-term stability under alkaline condition.In particular,when assembled as cathode and anode,the bifunctional V-Co_(2)P@HE catalyst can drive a current density of 10 mA cm^(-2)with only 1.53 V.This work provides new strategies for the application of highentropy MXene and the design of novel non-noble metal-based bifunctional electrolytic water catalysts.展开更多
基金provided by Science and Technology Development Project of Jilin Province(No.20230101338JC)。
文摘The printed circuit heat exchanger(PCHE) is receiving wide attention as a new kind of compact heat exchanger and is considered as a promising vaporizer in the LNG process. In this paper, a PCHE straight channel in the length of 500 mm is established, with a semicircular cross section in a diameter of 1.2 mm.Numerical simulation is employed to investigate the flow and heat transfer performance of supercritical methane in the channel. The pseudo-boiling theory is adopted and the liquid-like, two-phase-like, and vapor-like regimes are divided for supercritical methane to analyze the heat transfer and flow features.The results are presented in micro segment to show the local convective heat transfer coefficient and pressure drop. It shows that the convective heat transfer coefficient in segments along the channel has a significant peak feature near the pseudo-critical point and a heat transfer deterioration when the average fluid temperature in the segment is higher than the pseudo-critical point. The reason is explained with the generation of vapor-like film near the channel wall that the peak feature related to a nucleateboiling-like state and heat transfer deterioration related to a film-boiling-like state. The effects of parameters, including mass flow rate, pressure, and wall heat flux on flow and heat transfer were analyzed.In calculating of the averaged heat transfer coefficient of the whole channel, the traditional method shows significant deviation and the micro segment weighted average method is adopted. The pressure drop can mainly be affected by the mass flux and pressure and little affected by the wall heat flux. The peak of the convective heat transfer coefficient can only form at high mass flux, low wall heat flux, and near critical pressure, in which condition the nucleate-boiling-like state is easier to appear. Moreover,heat transfer deterioration will always appear, since the supercritical flow will finally develop into a filmboiling-like state. So heat transfer deterioration should be taken seriously in the design and safe operation of vaporizer PCHE. The study of this work clarified the local heat transfer and flow feature of supercritical methane in microchannel and contributed to the deep understanding of supercritical methane flow of the vaporization process in PCHE.
基金supported by Natural Science Foundation of Gansu (No.21JR7RA111)CAS Light of West China Program (2020XBZG-XBQNXZ-A)the 2022 Major scientific Research Project Cultivation Plan of Northwest Normal University (WNU-LKZD2022-04).
文摘Global warming and frequent extreme drought events lead to tree death and extensive forest decline,but the underlying mechanism is not clear.In drought years,cambial development is more sensitive to climate change,but in different phenological stages,the response rela-tionship is nonlinear.Therefore,the dynamic relationship between tree radial growth and climatic/environmental fac-tors needs to be studied.We thus continuously monitored radial growth of Qinghai spruce(Picea crassifolia Kom.)and environmental factors from January 2021 to November 2022 using point dendrometers and portable meteorological weather stations in the central area of the Qilian Mountains.The relationship and stability between the radial growth of Qinghai spruce and environmental factors were compared for different levels of drought in 2021 and 2022.The year 2022 had higher temperatures and less precipitation and was drier than 2021.Compared with 2021,the growing period in 2022 for Qinghai spruce was 10 days shorter,maximum growth rate(Grmax)was 4.5μm·d^(-1) slower,and the initiation of growth was 6 days later.Growth of Qinghai spruce was always restricted by drought,and the stem radial increment(SRI)was more sensitive to precipitation and air relative humidity.Seasonal changes in cumulative radial growth were divided into four phenological stages according to the time of growth onset,cessation,and maximum growth rate(Grmax)of Qinghai spruce.Stability responses of SRI to climate change were stronger in Stage 3 and Stage 4 of 2021 and stronger in Stage 1(initiation growth stage)and Stage 3 of 2022.The results provide important information on the growth of the trees in response to drought and for specific managing forests as the climate warms.
基金supported by the National Natural Science Foundation of China (52374311)the National Natural Science Foundation of Shaanxi (2022KXJ-146)+3 种基金the Fundamental Research Funds for the Central Universities (D5000230091)Open project of Shaanxi Laboratory of Aerospace Power (2022ZY2-JCYJ-01-09)full-depth-sea battery project (No.2020-XXXX-XX-246-00)the Youth Innovation Team of Shaanxi Universities。
文摘The spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode active materials(CAMs)are considered a promising alternative to commercially available cathodes such as layered and polyanion oxide cathodes,primarily due to their notable safety and high energy density,particularly in their single-crystal type.Nevertheless,the industrial application of the LNMO CAMs is severely inhibited due to the interfacial deterioration and corrosion under proton-rich and high-voltage conditions.This study successfully designed and synthesized two typical types of crystal facets-exposed single-crystal LNMO CAMs.By tracking the electrochemical deterioration and chemical corrosion evolution,this study elucidates the surface degradation mechanisms and intrinsic instability of the LNMO,contingent upon their crystal facets.The(111)facet,due to its elevated surface energy,is found to be more susceptible to external attack compared to the(100)and(110)facets.Our study highlights the electrochemical corrosion stability of crystal plane engineering for spinel LNMO CAMs.
基金Project supported by the National Natural Science Foundation of China (Grant No.12074273)the Sichuan Science and Technology Program (Grant No.2022NSFSC1810)。
文摘Boron phosphide(BP)has gained significant research attention due to its unique photoelectric and mechanical properties.In this work,we investigated the stability of BP under high pressure using x-ray diffraction and scanning electron microscope.The phase diagram of BP was explored in both B-rich and P-rich environments,revealing crucial insight into its behavior at 5.0 GPa.Additionally,we measured the melting curve of BP from 8.0 GPa to 15.0 GPa.Our findings indicate that the stability of BP under high pressure is improved within B-rich and P-rich environments.Furthermore,we report a remarkable observation of melting curve frustration at 10.0 GPa.This study will enhance our understanding of stability of BP under high pressure,shedding light on its potential application in semiconductor,thermal,and light-transmitting devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.52072322,22209137,51604250)the Department of Science and Technology of Sichuan Province(CN)(GrantNos.2022YFG0294,23GJHZ0147,23ZDYF0262)Production-Education Integration Demonstration Project of Sichuan Province"Photovoltaic Industry Production-Education Integration Comprehensive Demonstration Base of Sichuan Province"(Sichuan Financial Education[2022]No.106.n)。
文摘Sodium-based storage devices based on conversion-type metal sulfide anodes have attracted great atten-tion due to their multivalent ion redox reaction ability.However,they also suffer from sodium polysul-fides(NaPSs)shuttling problems during the sluggish Na^(+) redox process,leading to"voltage failure"and rapid capacity decay.Herein,a metal cobalt-doping vanadium disulfide(Co-VS_(2))is proposed to simulta-neously accelerate the electrochemical reaction of VS_(2) and enhance the bidirectional redox of soluble NaPSs.It is found that the strong adsorption of NaPSs by V-Co alloy nanoparticles formed in situ during the conversion reaction of Co-VS_(2) can effectively inhibit the dissolution and shuttle of NaPSs,and ther-modynamically reduce the formation energy barrier of the reaction path to effectively drive the complete conversion reaction,while the metal transition of Co elements enhances reconversion kinetics to achieve high reversibility.Moreover,Co-VS_(2) also produce abundant sulfur vacancies and unsaturated sulfur edge defects,significantly improve ionic/electron diffusion kinetics.Therefore,the Co-VS_(2) anode exhibits ultrahigh rate capability(562 mA h g^(-1) at 5 A g^(-1)),high initial coulombic efficiency(~90%)and 12,000 ultralong cycle life with capacity retention of 90%in sodium-ion batteries(SIBs),as well as impressive energy/power density(118 Wh kg^(-1)/31,250 W kg^(-1))and over 10.000 stable cycles in sodium-ion hybrid capacitors(SIHCs).Moreover,the pouch cell-type SIHC displays a high-energy density of 102 Wh kg^(-1) and exceed 600 stable cycles.This work deepens the understanding of the electrochemical reaction mechanism of conversion-type metal sulfide anodes and provides a valuable solution to the shuttlingofNaPSs inSIBsandSIHCs.
基金supported by National Science Foundation of China(No.52201254)Natural Science Foundation of Shandong Province(Nos.ZR2020MB090,ZR2020MB027,and ZR2020QE012)+1 种基金the project of“20 Items of University”of Jinan(No.202228046)the Taishan Scholar Project of Shandong Province(No.tsqn202306226)。
文摘The stacking and aggregation of graphene nanosheets have been obstacles to their application as electrode materials for microelectronic devices.This study deploys a one-step,scalable,facile electrochemical exfoliation technique to fabricate nitrogen(N)and chlorine(Cl)co-doped graphene nanosheets(i.e.,N-Cl-G)via the application of constant voltage on graphite in a mixture of 0.1 mol/L H_(2)SO_(4)and 0.1 mol/L NH_(4)Cl without using dangerous and exhaustive operation.The introduction of Cl(with its large radius)and N,both with high electrical negativity,facilitates the modulation of the electronic structure of graphene and creation of rich structural defects in it.Consequently,in the as-constructed supercapacitors,N-Cl-G exhibits a high specific capacitance of 77 F/g at 0.2 A/g and remarkable cycling stability with 91.7%retention of initial capacitance after 20,000 cycles at 10 A/g.Furthermore,a symmetrical supercapacitor assembled with N-Cl-G as the positive and negative electrodes(denoted as N-Cl-G//N-Cl-G)exhibits an energy density of 3.38 Wh/kg at a power density of 600 W/kg and superior cycling stability with almost no capacitance loss after 5000 cycles at 5 A/g.This study provides a scalable protocol for the facile fabrication of high-performance co-doped graphene as an electrode material candidate for supercapacitors.
基金This work was sponsored by Natural Science Foundation of Chongqing,China(cstc2021jcyjbshX0176 to Ting Gong)National Natural Science Foundation of China(81900980 to Huifen Ding).
文摘As we are facing an aging society,anti-aging strategies have been pursued to reduce the negative impacts of aging and increase the health span of human beings.Gut microbiota has become a key factor in the anti-aging process.Modulation of gut microbiota by fecal microbiota transplantation(FMT)to prevent frailty and unhealthy aging has been a hot topic of research.This narrative review summarizes the benefits of FMT for health span and lifespan,brains,eyes,productive systems,bones,and others.The mechanisms of FMT in improving healthy aging are discussed.The increased beneficial bacteria and decreased pathological bacteria decreased gut permeability and systemic inflammation,increased short-chain fatty acid(SCFA)and SCFA-producing bacteria,and other factors are listed as mechanisms of FMT to improve healthy aging.The points that need to be considered to ensure the optimal outcomes of FMT are also discussed,such as recipients’age,sex,genetic background,and gut microbiota after FMT.Although thisfield is still in its infancy,it has shown that FMT has great potential to improve healthy aging.
文摘Recent studies have highlighted the potential of plant extracts as therapeutic agents for managing oxidative stress and related disorders.This study aims to elucidate the phenolic composition and antioxidant properties of Gymnema sylvestre extracts.Ethanolic reflux extraction followed by column chromatography was employed to isolate phenolic compounds.The total phenolic and flavonoid contents were quantified using the Folin–Ciocalteu and aluminum chloride colorimetric methods,respectively.Antioxidant activities were assessed by DPPH,ABTS scavenging assays and the ferric reducing antioxidant power(FRAP)assay.High-Performance Liquid Chromatography(HPLC)with a C18 column and Thermo TSQ Quantum Access Max(LC-MS)were used to determine the levels of gymnemic acid and identify other potential phenolic compounds.The analysis revealed significant antioxidant activities in the fractions.Fraction A showed the highest DPPH and ABTS scavenging activities,and Fraction C demonstrated the highest ferric reducing power.LC-MS analysis identified several phenolic compounds,indicating that these are major contributors to the antioxidant efficacy of the extract.This study provides a detailed phenolic profile and confirms the strong antioxidant potential of Gymnema sylvestre leaf extract,supporting its therapeutic use and further investigation.
文摘Objective:To explore the effects of acupuncture and tuina combined with rehabilitation therapy on oxidative stress response and motor function in stroke hemiplegia patients.Methods:Sixty stroke hemiplegia patients were randomly divided into observation and control groups,with 30 cases each.The control group received conventional rehabilitation therapy,while the observation group also underwent acupuncture and tuina.After 8 weeks of treatment,oxidative stress indicators[malondialdehyde(MDA),superoxide dismutase(SOD),glutathione peroxidase(GSH-Px)],neurological deficit scores(NIHSS),Fugl-Meyer motor function scores(FMA),and activities of daily living(Barthel Index)were compared between the two groups.Results:Before treatment,there were no significant differences in MDA,NIHSS scores,FMA scores,and Barthel Index between the two groups(P>0.05).After 8 weeks,the observation group had lower MDA and NIHSS scores,but higher SOD,GSH-Px,FMA scores,and Barthel Index compared to the control group,with statistically significant differences(P<0.05).Conclusion:Acupuncture and tuina combined with rehabilitation therapy can effectively improve oxidative stress levels,promote neurological recovery,enhance motor function,and improve daily living activities in stroke hemiplegia patients.This combined therapy is recommended for clinical application.
基金Research and Practice of College English Writing Mixed Teaching Model Under the Guidance of OBE Concept of Education Reform Project of Guangdong Technology College(Project number:JXGG2024089)。
文摘English is an important course in colleges,and students’proficiency in the language can significantly affect their learning in multiple disciplines.At present,offline classroom teaching is still the primary mode of college English teaching,and online teaching has not been widely used.Under the background of new liberal arts,the teaching tasks and objectives of college English have changed,and it is imperative to carry out online-offline hybrid teaching mode.This paper analyzes the feasibility of the online-offline hybrid teaching mode of college English,summarizes its problems,and explores its implementation strategies in the context of the new liberal arts,to provide references for teachers.
文摘针对传统比例-积分-微分(proportional integral derivative,PID)控制和模型论控制方法难以应对新型电力系统背景下微电网面临的运行场景复杂多变的问题,提出了基于模糊神经网络的微电网荷储协调智能控制方法。首先确定了微电网模糊控制输入及输出变量,以平抑净负荷波动及减少储能充放电频次为目的,将微电网控制经验总结成模糊规则表,采用神经网络深度学习算法修正模糊控制模型的隶属度函数中心、宽度和输出权重来提高模型的自适应能力,从而制定了可调控负荷和储能的功率控制系数;进而针对模糊神经网络控制输出的负荷调控需求量在各可调控负荷间分配的问题,提出了基于灵活性供给指标排序的负荷调控优先级选择方法,最终完成了微电网系统储能单元和可调控负荷控制策略的制定。某典型微电网系统算例仿真结果表明,所提方法制定的各可调控负荷与储能控制策略能在避免储能频繁和过度充放电的同时,在并网状态下有效减弱并网功率对上级电网造成的随机扰动,在孤岛状态下能够有效平抑系统功率波动,提升系统运行稳定性。
基金financial support and the invaluable field assistance from the Forestry and Grassland Bureau of local counties in Qinghai ProvinceNational Natural Science Foundation of China(Grant No.32101237 and Grant No.41871294)Tibet Major Science and Technology Project(Grant No.XZ201901-GA-06)supported this work。
文摘Climate exerts a dominant control over the distribution of species.Generally,species migrate to higher elevations to track thermal niches,but variations in morphological traits can result in trait-specific responses to climate change.Here we attempted to explore how three sympatrically distributed raptor species(the Upland Buzzard Buteo hemilasius,UB;the Common Kestrel,also called Eurasian Kestrel Falco tinnunculus,EK;and the Saker Falcon Falco cherrug,SF)would respond to climate change over time,and whether their responses would bias by different morphology.We tested the alternative hypotheses for Allen’s rule for UB,EK,and SF in Qinghai Province,China,by modeling their current and future habitat suitability and confirming whether a consistent pattern exists between climate-induced range shifts and morphological differences among species.The extent of the projected distribution range within protected areas was also calculated for each species.We identified the future downward elevation shift for all the species,but with the notable northeastward shifting of the suitable climate space for UB and SF.Climate change would induce range contraction in the future,and the most acute influence is always the result of the pessimistic SSP585 scenario.No obvious pattern in climate-induced range shift was found for EK,for whom the morphological traits were significantly smaller all the time.More seriously,the ratios of highly suitable habitats being protected for our three raptor species were almost at a deficient level(below 1%).This study firstly tested the alternative hypothesis of Allen’s rule among raptors in Qinghai Province unprecedently,confirmed the morphological basis for different responses to changing climate across species,and demonstrated the protection deficiency under the current protected area design.We advocate more related studies in the future to verify our findings across more taxa.
基金supported by grants from the National Natural Science Foundation of China(No.81441016)and Key R&D Plan in Shaanxi Province of China(No.2020SF-262 and No.2019SF-200).
文摘Objective Cardiac fibroblasts(CFs)proliferation and extracellular matrix deposition are important features of cardiac fibrosis.Various studies have indicated that vitamin D displays an anti-fibrotic property in chronic heart diseases.This study explored the role of vitamin D in the growth of CFs via an integrin signaling pathway.Methods MTT and 5-ethynyl-2′-deoxyuridine assays were performed to determine cell viability.Western blotting was performed to detect the expression of proliferating cell nuclear antigen(PCNA)and integrin signaling pathway.The fibronectin was observed by ELISA.Immunohistochemical staining was employed to evaluate the expression of integrinβ3.Results The PCNA expression in the CFs was enhanced after isoproterenol(ISO)stimulation accompanied by an elevated expression of integrin beta-3(β3).The blockade of the integrinβ3 with a specific integrinβ3 antibody reduced the PCNA expression induced by the ISO.Decreasing the integrinβ3 by siRNA reduced the ISO-triggered phosphorylation of FAK and Akt.Both the FAK inhibitor and Akt inhibitor suppressed the PCNA expression induced by the ISO in the CFs.Calcitriol(CAL),an active form of vitamin D,attenuated the ISO-induced CFs proliferation by downregulating the integrinβ3 expression,and phosphorylation of FAK and Akt.Moreover,CAL reduced the increased levels of fibronectin and hydroxyproline in the CFs culture medium triggered by the ISO.The administration of calcitriol decreased the integrinβ3 expression in the ISO-induced myocardial injury model.Conclusion These findings revealed a novel role for CAL in suppressing the CFs growth by the downregulation of the integrinβ3/FAK/Akt pathway.
基金the financial supports from the National Natural Science Foundation of China(52222408)。
文摘Developing efficient,low-cost non-noble metal-based bifunctional catalysts to achieve excellent hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)kinetics in alkaline media is challenging but very meaningful.However,improving the electronic structure of the catalyst to optimize the adsorption of intermediates and reduce the reaction energy barrier is the key to improve the reaction efficiency.Herein,a V-doped Co_(2)P coupled with high-entropy MXene heterostructure catalyst(V-Co_(2)P@HE)was prepared by a two-step electrodeposition and controlled phosphorization process.The analyses of X-ray absorption spectroscopy,X-ray photoelectron spectroscopy and theoretical calculations jointly show that the introduction of V and the strong electron coupling between the two components optimize the adsorption energy of water molecules and reaction intermediates.Benefiting from the abundant active sites and optimizing intermediate adsorption energy and heterogeneous interface electronic structure,V-Co_(2)P@HE has excellent HER and OER activity and long-term stability under alkaline condition.In particular,when assembled as cathode and anode,the bifunctional V-Co_(2)P@HE catalyst can drive a current density of 10 mA cm^(-2)with only 1.53 V.This work provides new strategies for the application of highentropy MXene and the design of novel non-noble metal-based bifunctional electrolytic water catalysts.
