Recent progress in thermodynamic and kinetics modification of magnesium hydride hydrogen storage materials

Hydrogen energy has emerged as a pivotal solution to address the global energy crisis and pave the way for a cleaner,low-carbon,secure,and efficient modern energy system.A key imperative in the utilization of hydrogen energy lies in the development of high-performance hydrogen storage materials.Magnesium-based hydrogen storage materials exhibit remarkable advantages,including high hydrogen storage density,cost-effectiveness,and abundant magnesium resources,making them highly promising for the hydrogen energy sector.Nonetheless,practical applications of magnesium hydride for hydrogen storage face significant challenges,primarily due to their slow kinetics and stable thermodynamic properties.Herein,we briefly summarize the thermodynamic and kinetic properties of MgH2,encompassing strategies such as alloying,nanoscaling,catalyst doping,and composite system construction to enhance its hydrogen storage performance.Notably,nanoscaling and catalyst doping have emerged as more effective modification strategies.The discussion focuses on the thermodynamic changes induced by nanoscaling and the kinetic enhancements resulting from catalyst doping.Particular emphasis lies in the synergistic improvement strategy of incorporating nanocatalysts with confinement materials,and we revisit typical works on the multi-strategy optimization of MgH2.In conclusion,we conduct an analysis of outstanding challenges and issues,followed by presenting future research and development prospects for MgH2 as hydrogen storage materials.

Observation on the Nursing Effect of Ginger Moxibustion on Gastrointestinal Symptoms in Patients with Heart Failure Due to Yang Qi Deficiency

Objective:To evaluate the nursing measures and effects of ginger moxibustion in the treatment of heart failure(yang qi deficiency type)with gastrointestinal symptoms.Methods:86 patients with heart failure(yang qi deficiency type)accompanied by gastrointestinal symptoms who were admitted to the hospital between January 2023 and January 2024 were selected and divided into 43 cases in each group by random number table grouping;Group I implemented integrated care,while Group II adopted conventional care.The indicators of care were compared between the two groups.Results:After the nursing care,the digestive symptom scores of Group I were lower than those of Group I,and the psychological scores were lower than those of Group II(P<0.05).Conclusion:Ginger moxibustion can improve gastrointestinal symptoms and enhance the psychological health of patients with heart failure(yang qi deficiency type)with gastrointestinal symptoms.

外源赤霉素GA3对库尔勒香梨抗寒性的影响

以树势健壮、结果正常的库尔勒香梨单株为试验材料,在展叶期(2013年5月6日)第一次喷施不同浓度的 外源GA3 (50, 75, 100 mg/L),每隔20天喷施一次,共喷施三次。在休眠期枝条取样,在人工低温胁迫 条件下测定膜透性、丙二醛、脯氨酸、可溶性蛋白质、可溶性糖和淀粉含量等抗寒性指标,并计算各综 合指标的隶属度。试验结果表明:100 mg/L GA3一次处理的平均隶属度大于0.7,为高抗;50 mg/L GA3 一次处理、75 mg/L GA3一次处理、50 mg/L GA3二次处理、75 mg/L GA3二次处理、100 mg/L GA3二 次处理、100 mg/L GA3三次处理的平均隶属度均大于0.4,因此以上处理均为中抗;50 mg/L GA3三次处 理、75 mg/L GA3三次处理的平均隶属度大于0.3,因此这两种处理为低抗。可初步认为,最佳GA3喷施 浓度为100 mg/L,处理一次,能够抵抗?24℃的低温,但确定最佳喷施时间和外源激素浓度需进一步深 入研究。

Graphene oxide assisted facile hydrothermal synthesis of LiMn_(0.6)Fe_(0.4)PO_4 nanoparticles as cathode material for lithium ion battery

Assisted by graphene oxide（GO）,nano-sized LiMn0.6Fe0.4PO4 with excellent electrochemical performance was prepared by a facile hydrothermal method as cathode material for lithium ion battery.SEM and TEM images indicate that the particle size of LiMn0.6Fe0.4PO4（S2）was about 80 nm in diameter.The discharge capacity of LiMn0.6Fe0.4PO4 nanoparticles was 140.3 mAh-g^1 in the first cycle.It showed that graphene oxide was able to restrict the growth of LiMn0.6Fe0.4PO4 and it in situ reduction of GO could improve the electrical conductivity of LiMn0.6Fe0.4PO4 material.

High specific surface area porous graphene grids carbon as anode materials for sodium ion batteries

Although great accomplishments of functional material synthesis have been achieved in sodium ion batteries(SIBs)recently,there are still numerous challenges and problems in preparing carbon-based materials with porous architectures and enough lattice distance for Na^+insertion.Herein we report a templated strategy to synthesize 3D porous graphene girds(PGGs)consisting of several stacking graphene structure with ultrahigh surface area and hierarchical connected structure by employing Ag nanoparticles(NPs).The Ag NPs will regenerate for decreasing the experimental cost,also in line with principles of green chemistry and environmentally friendly strategy.The PGGs obtain advanced specific capacity of160 m A h g^(-1)at current density of 50 m A h g^(-1).Moreover,112 mA h g^(-1)capacity can be gained at 1 A h g^(-1)during 1000 cycles.Due to their porous architecture,ultrahigh surface area and low amorphous graphited structure,PGGs electrode showed the excellent electrochemical performance in high rate capability.

Intercalation engineering of layered vanadyl phosphates for high performance zinc-ion batteries

Aqueous zinc-ion batteries(ZIBs) have attracted great attention as the candidates for large-scale energy storage system,recently,because of their low cost,environment-friendly,high safety,and high theoretical energy densities.Among the numerous cathode materials,layered structure vanadium based polyanionic compounds,such as VOPO_(4),exhibit high specific capacity for Zn ion storage.However,the low Zn ion diffusion coefficient and limited interlayer spacing make the cathodes low reversible capacity and inferior cycling stability.Herein,K ions were pre-intercalated into the VOPO_(4) layers via ions exchange adopting VOPO_(4)·2 H_(2) O as the precursor.When evaluated as the cathode for ZIBs,an excellent cycle stability of 400 cycles under a current density of 500 mA g^(-1) was achieved by the obtained KVOPO_(4) electrode,verifying the positive effect of intercalation engineering.Furtherly,a solid-solution reaction Zn ion storage mechanism was confirmed.This study provides a new insight to explore high performance cathode materials for ZIBs.

Coupled cobalt-doped molybdenum carbide@N-doped carbon nanosheets/nanotubes supported on nickel foam as a binder-free electrode for overall water splitting

In an attempt to develop low-cost,non-noble-metal bifunctional electrocatalysts for water electrolysis in alkaline media,cobalt-doped molybdenum carbide@N-doped carbon nanosheets/nanotubes were fabricated by using C3N4 as the carbon source on a 3D porous nickel foam substrate.Benefiting from the optimized electronic structure and enhanced mass and charge transport,as well as the 3D conducting pathway,MoxCoy@N-CNSs/CNTs shows superior performance towards both the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in an alkaline medium.The optimal electrocatalyst is Mo2Co1@N-CNSs/CNTs,which reveals a current density of 10 mA cm^-2 at the low overpotentials of 99 mV and 300 mV for the HER and OER,respectively,and a relatively low cell voltage(1.63 V)for the overall water electrolysis.The method of optimizing the composition and nanostructure of a material provides a new avenue for the development and utilization of high-performance electrocatalysts.

Dehydrogenation characteristics of LiAlH4 improved by in-situ formed catalysts

The hydrogen storage properties and catalytic mechanism of FeCl-doped LiAlHwere investigated in minute details. LiAlH-2 mol% FeClsamples start to release hydrogen at 76 °C, which is 64 °C lower than that of as-received LiAlH. Isothermal desorption measurements show that the 2 mol% FeCl-doped sample releases 7.0 wt% of hydrogen within 17 min at 250 °C. At lower temperatures of 110 °C and 80 °C, the sample can release 4.4 wt% and 3 wt% of hydrogen, respectively. The apparent activation energy of LiAlH-2 mol% FeClsamples for R2 is 105.02 k J/mol, which is 67 k J/mol lower than that of pure LiAlH. The reaction between LiAlHand FeClduring ball milling was found by analyzing the X-ray diffraction results,and Fe-Al particles formed in-situ from the reaction act as the real catalyst for the dehydrogenation of LiAlH.

Novel application of LiCoO_2 as a high-performance candidate material for supercapacitor

Electrochemical performances of LiCoO_2 as a candidate material for supercapacitor are systematically investigated. LiCoO_2 nanomaterials are synthesized via hydrothermal reaction with consequent calcination process. And the particle size increases as the calcination temperature rises. LCO-650 sample with the largest particle size displays the maximum capacitances of 817.5 F·g^-1 with the most outstanding capacity retention rate of 96.8% after 2000 cycles. It is shown that large particle size is beneficial to the electrochemical and structural stability of LiCoO_2 materials. We speculate that the micron-sized waste LiCoO_2 materials have great potential for supercapacitor application. It may provide a novel recovered approach for spent LIBs and effectively relieve the burdens on the resource waste and environment pollution.

Synergetic effects of NaAlH_4-TiF_3 co-additive on dehydriding reaction of Mg(AlH_4)_2

The effects of NaA1H4, TiF3 and NaA1H4-TiF3 co-additive on dehydriding reaction of Mg（A1H4）2 are systematically investigated. The on- set dehydrogenation temperature of the co-doped Mg（A1H4）2 composites decreased to 74 ℃, which is about 59 ℃ lower than that of pure Mg（A1H4）2. The dehydrogenation kinetics of NaA1H4-TiF3 co-doped Mg（A1H4）2 sample was also improved, which released about 94% hydrogen within 48 min, but no visible hydrogen was released from pure Mg（A1H4）2 under the same conditions. The activation energy of co-doped Mg（A1H4）2 was 85.6 kJ.mol-t, which was significantly lower than that of additive-free Mg（A1H4）2 sample. The synergetic effects of NaA1H4 and TiF3 on the dehydrogenation performance of Mg（A1H4）2 were confirmed. In addition, a possible catalytic mechanism is discussed, regarding the different roles of NaA1H4 and TiF3 on Mg（A1H4）2.

Reproductive health in Southeast Asian women:current situation and the influence factors

Background:The reproductive health addresses the reproductive processes,functions and system at all stages of life.Enhancing the level of global reproductive health is the goal of sustained attention and struggle by the international community.The social and economic development in Southeast Asia is lagging behind,and its female reproductive health is worrying,while the differences of female reproductive health among different regions are significant.Objective:To obtains the necessity and urgency of strengthening the reproductive health level of Southeast Asian countries,so as to provide the basis for the priorities and target to policy-makers and health administrators to improve reproductive health.Methods:Literature review were searched in PubMed,Web of Science databases,Google scholar database,and WHO's webpages.Maternal mortality ratio,contraceptive rates,unmet need for family planning,antenatal and postnatal care coverage,and sexually transmitted disease were the five key indicators and the influence factors for female reproductive health status in Southeast Asian countries.Results:The reproductive health of Southeast Asian women were still at a lower level overall and varied in different regions and conntries.Women's education and attitude,accessibility of service,socioeconomic and cultural factors,etc.were the potential influencing factors.Conclusion:There is left quite large space for improvement to the reproductive health in Southeast Asian countries and efficient interventions can be achieved for the key and easier-improved risk factors such as education and in high-risk areas.

State-of-charge Balance Control and Safe Region Analysis for Distributed Energy Storage Systems with Constant Power Loads

This paper presents a fully distributed state-of-charge balance control (DSBC) strategy for a distributed energy storage system (DESS). In this framework, each energy storage unit (ESU) processes the state-of-charge (SoC) information from its neighbors locally and adjusts the virtual impedance of the droop controller in real-time to change the current sharing. It is shown that the SoC balance of all ESUs can be achieved. Due to virtual impedance, voltage deviation of the bus occurs inevitably and increases with load power. Meanwhile, widespread of the constant power load (CPL) in the power system may cause instability. To ensure reliable operation of DESS under the proposed DSBC, the concept of the safe region is put forward. Within the safe region, DESS is stable and voltage deviation is acceptable. The boundary conditions of the safe region are derived from the equivalent model of DESS, in which stability is analyzed in terms of modified Brayton-Moser's criterion. Both simulations and hardware experiments verify the accuracy of the safe region and effectiveness of the proposed DSBC strategy.

Analyzing the cellular and molecular atlas of ovarian mesenchymal cells provides a strategy against female reproductive aging

Ovarian mesenchymal cells(oMCs)constitute a distinct microenvironment that supports folliculogenesis under physiological conditions.Supplementation of exogenous non-ovarian mesenchymal-related cells has been reported to be an efficient approach to improve ovarian functions.However,the development and cellular and molecular characteristics of endogenous oMCs remain largely unexplored.In this study,we surveyed the single-cell transcriptomic landscape to dissect the cellular and molecular changes associated with the aging of oMCs in mice.Our results showed that the oMCs were composed of five ovarian differentiatedMC(odMC)populations and one ovarian mesenchymal progenitor(oMP)cell population.These cells could differentiate into various odMCs via an oMP-derived route to construct the ovarian stroma structures.Comparative analysis revealed that ovarian aging was associated with decreased quantity of oMP cells and reduced quality of odMCs.Based on the findings of bioinformatics analysis,we designed different strategies involving supplementation with young oMCs to examine their effects on female fertility and health.Our functional investigations revealed that oMCs supplementation prior to ovarian senescence was the optimal method to improve female fertility and extend the reproductive lifespan of aged females in the longterm.

Performance Comparison of Computational Methods for the Prediction of the Function and Pathogenicity of Non-coding Variants

Non-coding variants in the human genome significantly influence human traits and complex diseases via their regulation and modification effects.Hence,an increasing number of computational methods are developed to predict the effects of variants in human non-coding sequences.However,it is difficult for inexperienced users to select appropriate computational methods from dozens of available methods.To solve this issue,we assessed 12 performance metrics of 24 methods on four independent non-coding variant benchmark datasets:(1)rare germline variants from clinical relevant sequence variants(ClinVar),(2)rare somatic variants from Catalogue Of Somatic Mutations In Cancer(COSMIC),(3)common regulatory variants from curated expression quantitative trait locus(eQTL)data,and(4)disease-associated common variants from curated genomewide association studies(GWAS).All 24 tested methods performed differently under various conditions,indicating varying strengths and weaknesses under different scenarios.Importantly,the performance of existing methods was acceptable for rare germline variants from ClinVar with the area under the receiver operating characteristic curve(AUROC)of 0.4481–0.8033 and poor for rare somatic variants from COSMIC(AUROC=0.4984–0.7131),common regulatory variants from curated eQTL data(AUROC=0.4837–0.6472),and disease-associated common variants from curated GWAS(AUROC=0.4766–0.5188).We also compared the prediction performance of 24 methods for non-coding de novo mutations in autism spectrum disorder,and found that the combined annotation-dependent depletion(CADD)and context-dependent tolerance score(CDTS)methods showed better performance.Summarily,we assessed the performance of 24 computational methods under diverse scenarios,providing preliminary advice for proper tool selection and guiding the development of new techniques in interpreting non-coding variants.

Bicriteria Algorithms for Approximately Submodular Cover Under Streaming Model

In this paper,we mainly investigate the optimization model that minimizes the cost function such that the cover function exceeds a required threshold in the set cover problem,where the cost function is additive linear,and the cover function is non-monotone approximately submodular.We study the problem under streaming model and propose three bicriteria approximation algorithms.Firstly,we provide an intuitive streaming algorithm under the assumption of known optimal objective value.The intuitive streaming algorithm returns a solution such that its cover function value is no less thanα(1−ϵ)times threshold,and the cost function is no more than(2+ϵ)^(2)/(ϵ^(2)ω^(2))⋅κ,whereκis a value that we suppose for the optimal solution andαis the approximation ratio of an algorithm for unconstrained maximization problem that we can call directly.Next we present a bicriteria streaming algorithm scanning the ground set multi-pass to weak the assumption that we guess the optimal objective value in advance,and maintain the same bicriteria approximation ratio.Finally we modify the multi-pass streaming algorithm to a single-pass one without compromising the performance ratio.Additionally,we also propose some numerical experiments to test our algorithm’s performance comparing with some existing methods.

Research on Interest Rate Transmission Mechanism of China’s Bond Market:Empirical Analysis Based on Granger Causality Complex Network

The bond market is an important market for investment and financing in China’s economic sectors,and also an important part of the monetary policy framework.The internal transmission of bond market is an important part of market interest rate transmission,which iscritical to the effectiveness of monetary policy.However,few scholars have studied the characteristics of interest rate transmission in China.An in-depth study of the interest rate transmission mechanism and its dynamic evolution between different bond markets is conducive to clarify the pulse of transmission within Chinese bond market and to further unblock the transmission mechanism of monetary policy.From the perspective of system theory and based on the analysis method of Granger causality complex network,this paper finds that the interest rate transmission among various varieties in China’s bond market is relatively significant.Treasury bonds and CDB bonds are the two core bond varieties of interest rate transmission in the bond market.Simultaneously,this study concludes that the medium and long-term interest rate played a dominant role in the transmission of market interest rate during the easing phase of monetary policy,while the short-term interest rate played a dominant role in the transmission of market interest rate during the tightening phase of monetary policy.This paper also gives enlightenment and suggestions.

钢箱梁竖向温度梯度规范条文的对比与实测

钢结构桥梁处于复杂自然环境中,其温度将随太阳辐射和气温的影响而变化。这种温度变化不仅有均匀的整体温升温降,也有沿横桥向和主梁竖向的不均匀分布。桥梁结构温度的变化和不均匀分布将导致结构热胀冷缩,使得结构发生位移或形变,当这种位移或形变受到约束时,将在结构中产生较大的次内力和温度次应力。在某些不利条件下,结构某些部位产生的温度次应力可能大于车辆或其他活载产生的应力。桥梁设计如忽略或未能正确估计温度荷载效应可能会导致桥梁损坏甚至发生倒塌。为研究太阳辐射下闭口钢箱梁的竖向温度梯度大小和分布特征,首先比较了国内外四个主要规范对主梁或钢箱梁竖向温度梯度的规定,其中,仅欧洲规范1明确规定了钢箱梁的竖向温度梯度模式。然后以长沙湘江三汊矶大桥钢箱梁内的温度实测为研究对象,通过在钢箱梁同一个横隔板上横桥向布设两个温度测试断面,在夏季强太阳辐射和高环境温度的天气条件下,对两个断面上的测点温度进行了多次测量,获得了24 h内铺装层顶面、钢箱梁面板、箱内空气、钢箱底板和环境温度,分析了横隔板上不同测点的竖向温度随时间的变化规律。研究表明:在高温天气和强烈太阳辐射作用下,铺装层顶面、钢箱梁顶板、箱内空气、钢箱底板和环境温度表现出相同的变化趋势;太阳辐射使得桥面铺装快速升温并在14:00左右达到最大值;钢箱梁面板温度在16:00左右达到最高值;面板和底板在14:00—18:00之间存在较大的温差,记录的最大正温差在14:30左右达到最大值(16.8℃);竖向正温度梯度分布为非线性,观测到的梁顶正温差大,但其负温差明显偏小。基于获得的顶底板最大温差,采用四折线拟合了横隔板竖向温度梯度,5个参考点离开顶板的距离分别是0,100,300,650 mm和梁高h,对应的5个温度梯度值分别是ΔT_(1)=17℃、ΔT_(2)=13℃、ΔT_(3)=8℃、ΔT_(4)=4.5℃和0℃。研究表明,欧洲规范1的四折线模式能用于描述该钢桥钢箱梁竖向温度梯度。

High-entropy(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2))_(2)Ce_(2)O_(7):A potential thermal barrier material with improved thermo-physical properties

High-entropy oxides(HEOs)are widely researched as potential materials for thermal barrier coatings(TBCs).However,the relatively low thermal expansion coefficient(TEC)of those materials severely restricts their practical application.In order to improve the poor thermal expansion property and further reduce the thermal conductivity,high-entropy(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2))_(2)Ce_(2)O_(7) is designed and synthesized in this work.The as-prepared multicomponent material is formed in a simple disordered fluorite structure due to the high-entropy stabilization effect.Notably,it exhibits a much higher TEC of approximately 12.0×10^(−6) K^(−1) compared with those of other high-entropy oxides reported in the field of TBCs.Besides,it presents prominent thermal insulation behavior with a low intrinsic thermal conductivity of 0.92 W·m^(−1)·K^(−1) at 1400℃,which can be explained by the existence of high concentration oxygen vacancies and highly disordered arrangement of multicomponent cations in the unique high-entropy configuration.Through high-temperature in-situ X-ray diffraction(XRD)measurement,this material shows excellent phase stability up to 1400℃.Benefiting from the solid solution strengthening effect,it shows a higher hardness of 8.72 GPa than the corresponding single component compounds.The superior thermo-physical performance above enables(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2))_(2)Ce_(2)O_(7) a promising TBC material.

Lightweight hydrides nanocomposites for hydrogen storage: Challenges, progress and prospects

As typical high-capacity complex hydrides,lightweight hydrides have attracted intensive attention due to their high gravimetric and volumetric energy densities of hydrogen storage.However,lightweight hydrides also have high thermodynamic stability and poor kinetics,so they ususally require high hydrogen desorption temperature and show inferior reversibility under mild conditions.This review summarizes recent progresses on the endeavor of overcoming thermodynamic and kinetic challenges for Mg based hydrides,lightweight metal borohydrides and alanates.First,the current state,advantages and challenges for Mg-based hydrides and lightweight metal hydrides are introduced.Then,alloying,nanoscaling and appropriate doping techniques are demonstrated to decrease the hydrogen desorption temperature and promote the reversibility behavior in lightweight hydrides.Selected scaffolds materials,approaches for synthesis of nanoconfined systems and hydriding-dehydriding properties are reviewed.In addition,the evolution of various dopants and their effects on the hydrogen storage properties of lightweight hydrides are investigated,and the relevant catalytic mechanisms are summarized.Finally,the remaining challenges and the sustainable research efforts are discussed.

Ethylenediurea（EDU） pretreatment alleviated the adverse effects of elevated O3 on Populus alba "Berolinensis" in an urban area

Ethylenediurea(EDU)has been used as a chemical protectant against ozone(O3).However,its protective effect and physiological mechanisms are still uncertain.The present study aimed to investigate the changes of foliar visible injury,physiological characteristics and emission rates of volatile organic compounds(VOCs)in one-year-old Populus alba"Berolinensis"saplings pretreated with EDU and exposed to elevated O3(EO,120μg/m3).The results showed that foliar visible injury symptoms under EO were significantly alleviated in plants with EDU application(p<0.05).Under EO,net photosynthetic rate,the maximum photochemical efficiency of PSII and the photochemical efficiency of PSII of plants pretreated with 300 and600 mg/L EDU were similar to unexposed controls and significantly higher compared to EOstressed plants without EDU pretreatment,respectively.Malondialdehyde content was highest in EO without EDU and decreased significantly by 14.9%and 21.3%with 300 and600 mg/L EDU pretreatment,respectively.EDU pretreatment alone increased superoxide dismutase activity by 10-fold in unexposed plants with further increases of 88.4%and 37.5%in EO plants pretreated with 300 and 600 mg/L EDU pretreatment,respectively(p<0.05).Abscisic acid content declined under EO relative to unexposed controls with the effect partially reversed by EDU pretreatments.Similarly,VOCs emission rate declined under EO relative to unexposed plants with a recovery of emission rate observed with 300 and 600 mg/L EDU pretreatment.These findings provided significant evidence that EDU exerted a beneficial effect and protection on the tested plants against O3 stress.