Rapid and stable calcium-looping solar thermochemical energy storage via co-doping binary sulfate and Al–Mn–Fe oxides

Solar thermochemical energy storage based on calcium looping(CaL)process is a promising technology for next-generation concentrated solar power(CSP)systems.However,conventional calcium carbonate(CaCO_(3))pellets suffer from slow reaction kinetics,poor stability,and low solar absorptance.Here,we successfully realized high power density and highly stable solar thermochemical energy storage/release by synergistically accelerating energy storage/release via binary sulfate and promoting cycle stability,mechanical strength,and solar absorptance via Al–Mn–Fe oxides.The energy storage density of proposed CaCO_(3)pellets is still as high as 1455 kJ kg^(-1)with only a slight decay rate of 4.91%over 100 cycles,which is higher than that of state-of-the-art pellets in the literature,in stark contrast to 69.9%of pure CaCO_(3)pellets over 35 cycles.Compared with pure CaCO_(3),the energy storage power density or decomposition rate is improved by 120%due to lower activation energy and promotion of Ca^(2+)diffusion by binary sulfate.The energy release or carbonation rate rises by 10%because of high O^(2-)transport ability of molten binary sulfate.Benefiting from fast energy storage/release rate and high solar absorptance,thermochemical energy storage efficiency is enhanced by more than 50%under direct solar irradiation.This work paves the way for application of direct solar thermochemical energy storage techniques via achieving fast energy storage/release rate,high energy density,good cyclic stability,and high solar absorptance simultaneously.

Mn-doped SrCoO_(3-δ) Perovskite Oxides for Ethylene Production via Chemical Looping Oxidative Dehydrogenation of Ethane

Chemical looping oxidative dehydrogenation (CL-ODH) is an economically promising method for convertingethane into higher value-added ethylene utilizing lattice oxygen in redox catalysts, also known as oxygen carriers. Inthis study, perovskite-type oxide SrCoO_(3-δ) and B-site Mn ion-doped oxygen carriers (SrCo_(1-x)MnxO_(3-δ), x=0.1, 0.2, 0.3)were prepared and tested for the CL-ODH of ethane. The oxygen-deficient perovskite SrCoO_(3-δ) exhibited high ethyleneselectivity of up to 96.7% due to its unique oxygen vacancies and lattice oxygen migration rates. However, its low ethyleneyield limits its application in the CL-ODH of ethane. Mn doping promoted the reducibility of SrCoO_(3-δ) oxygen carriers,thereby improving ethane conversion and ethylene yield, as demonstrated by characterization and evaluation experiments.X-ray diffraction results confirmed the doping of Mn into the lattice of SrCoO_(3-δ), while X-ray photoelectron spectroscopy(XPS) indicated an increase in lattice oxygen ratio upon incorporation of Mn into the SrCoO_(3-δ) lattice. Additionally, H2temperature-programmed reduction (H2-TPR) tests revealed more peaks at lower temperature reduction zones and a declinein peak positions at higher temperatures. Among the four tested oxygen carriers, SrCo0.8Mn0.2O_(3-δ) exhibited satisfactoryperformance with an ethylene yield of 50% at 710 °C and good stability over 20 redox cycles. The synergistic effect of Mnplays a key role in increasing ethylene yields of SrCoO_(3-δ) oxygen carriers. Accordingly, SrCo0.8Mn0.2O_(3-δ) shows promisingpotential for the efficient production of ethylene from ethane via CL-ODH.

Optimizing the sulfur-resistance and activity of perovskite oxygen carrier for chemical looping dry reforming of methane

Perovskite oxides has been attracted much attention as high-performance oxygen carriers for chemical looping reforming of methane,but they are easily inactivated by the presence of trace H_(2)S.Here,we propose to modulate both the activity and resistance to sulfur poisoning by dual substitution of Mo and Ni ions with the Fe-sites of LaFeO_(3)perovskite.It is found that partial substitution of Ni for Fe substantially improves the activity of LaFeO_(3)perovskite,while Ni particles prefer to grow and react with H_(2)S during the long-term successive redox process,resulting in the deactivation of oxygen carriers.With the presence of Mo in LaNi_(0.05)Fe_(0.95)O_(3−σ)perovskite,H_(2)S preferentially reacts with Mo to generate MoS_(2),and then the CO_(2)oxidation can regenerate Mo via removing sulfur.In addition,Mo can inhibit the accumulation and growth of Ni,which helps to improve the redox stability of oxygen carriers.The LaNi_(0.05)Mo_(0.07)Fe_(0.88)O_(3−σ)oxygen carrier exhibits stable and excellent performance,with the CH_(4)conversion higher than 90%during the 50 redox cycles in the presence of 50 ppm H_(2)S at 800℃.This work highlights a synergistic effect in the perovskite oxides induced by dual substitution of different cations for the development of high-performance oxygen carriers with excellent sulfur tolerance.

Chemical looping reforming of the micromolecular component from biomass pyrolysis via Fe_(2)O_(3)@SBA-16

To solve the problems of low gasification efficiency and high tar content caused by solid–solid contact between biomass and oxygen carrier in traditional biomass chemical looping gasification process.The decoupling strategy was adopted to decouple the biomass gasification process,and the composite oxygen carrier was prepared by embedding Fe_(2)O_(3) in molecular sieve SBA-16 for the chemical looping reforming process of pyrolysis micromolecular model compound methane,which was expected to realize the directional reforming of pyrolysis volatiles to prepare hydrogen-rich syngas.Thermodynamic analysis of the reaction system was carried out based on the Gibbs free energy minimization method,and the reforming performance was evaluated by a fixed bed reactor,and the kinetic parameters were solved based on the gas–solid reaction model.Thermodynamic analysis verified the feasibility of the reaction and provided theoretical guidance for experimental design.The experimental results showed that the reaction performance of Fe_(2)O_(3)@SBA-16 was compared with that of pure Fe_(2)O_(3) and Fe_(2)O_(3)@SBA-15,and the syngas yield was increased by 55.3%and 20.7%respectively,and it had good cycle stability.Kinetic analysis showed that the kinetic model changed from three-dimensional diffusion to first-order reaction with the increase of temperature.The activation energy was 192.79 kJ/mol by fitting.This paper provides basic data for the directional preparation of hydrogen-rich syngas from biomass and the design of oxygen carriers for pyrolysis of all-component chemical looping reforming.

Ethane Chemical Looping Oxidative Dehydrogenation to Ethylene over Co_(2)O_(3)(Fe_(2)O_(3),NiO)/LaCoO_(3) Oxygen Carriers

Ethane chemical looping oxidative dehydrogenation(CL-ODH)to ethylene is a new technology for converting ethane to ethylene.In the current study MeO/LaCoO_(3)(MeO=Fe_(2)O_(3),NiO or Co_(2)O_(3))composite metal oxides were prepared via citrate gel and impregnation methods,and used as oxygen carriers for CL-ODH.X-ray diffraction results indicated that all oxygen carriers had a perovskite structure even after eight redox cycles.Under a reaction temperature of 650°C,a reaction pressure of 0.1 MPa,and a weight hourly space velocity(WHSV)of 7500 mL/(g·h),ethane conversion over Co_(2)O_(3)/LaCoO_(3) reached 100%and ethylene selectivity reached 60%,both of which were better than corresponding values attained over Fe_(2)O_(3)/LaCoO_(3) and NiO/LaCoO_(3).Ethylene selectivity remained stable for 80 cycles over Co_(2)O_(3)/LaCoO_(3),then decreased gradually after 80 cycles.X-ray photoelectron spectroscopy results and evaluation results indicated that lattice oxygen and O_(2)2-had a direct relationship with ethane conversion and ethylene selectivity.Co_(2)O_(3)/LaCoO_(3) exhibited a strong capacity to release and absorb oxygen,mainly due to interaction between Co_(2)O_(3) and LaCoO_(3).

CO_(2)capture costs of chemical looping combustion of biomass:A comparison of natural and synthetic oxygen carrier

Chemical looping combustion has the potential to be an efficient and low-cost technology capable of contributing to the reduction of the atmospheric concentration of CO_(2) in order to reach the 1.5/2°C goal and mitigate climate change.In this process,a metal oxide is used as oxygen carrier in a dual fluidized bed to generate clean CO_(2) via combustion of biomass.Most commonly,natural ores or synthetic materials are used as oxygen carrier whereas both must meet special requirements for the conversion of solid fuels.Synthetic oxygen carriers are characterized by higher reactivity at the expense of higher costs versus the lower-cost natural ores.To determine the viability of both possibilities,a techno-economic comparison of a synthetic material based on manganese,iron,and copper to the natural ore ilmenite was conducted.The synthetic oxygen carrier was characterized and tested in a pilot plant,where high combustion efficiencies up to 98.4%and carbon capture rates up to 98.5%were reached.The techno-economic assessment resulted in CO_(2) capture costs of 75 and 40€/tCO_(2) for the synthetic and natural ore route respectively,whereas a sensitivity analysis showed the high impact of production costs and attrition rates of the synthetic material.The synthetic oxygen carrier could break even with the natural ore in case of lower production costs and attrition rates,which could be reached by adapting the production process and recycling material.By comparison to state-of-the-art technologies,it is demonstrated that both routes are viable and the capture cost of CO_(2) could be reduced by implementing the chemical looping combustion technology.

Advancements in biomass gasification research utilizing iron-based oxygen carriers in chemical looping:A review

Biomass,recognized as renewable green coal,is pivotal for energy conservation,emission reduction,and dualcarbon objectives.Chemical looping gasification,an innovative technology,aims to enhance biomass utilization efficiency.Using metal oxides as oxygen carriers regulates the oxygen-to-fuel ratio to optimize synthesis product yields.This review examines various oxygen carriers and their roles in chemical looping biomass gasification,including natural iron ore types,industrial by-products,cerium oxide-based carriers,and core-shell structures.The catalytic,kinetic,and phase transfer properties of iron-based oxygen carriers are analyzed,and their catalytic cracking capabilities are explored.Molecular interactions are elucidated and system performance is optimized by providing insights into chemical looping reaction mechanisms and strategies to improve carrier efficiency,along with discussing advanced techniques such as density functional theory(DFT)and reactive force field(ReaxFF)molecular dynamics(MD).This paper serves as a roadmap for advancing chemical looping gasification towards sustainable energy goals.

NiO-Doped Fe_(2)O_(3)/MgO Properties for the Chemical Looping Oxidative Dehydrogenation of Ethane

Ethane chemical looping oxidative dehydrogenation(CL-ODH)to ethylene is a new technology for ethylene preparation.Fe_(2)O_(3)/MgO oxygen carrier was prepared using the co-precipitation method.The influence of added NiO and its different loadings on Fe_(2)O_(3)/MgO were investigated.Then,a series of oxygen carriers were applied in the CL-ODH of the ethane cycle system.Brunauer-Emmett-Teller(BET),X-ray diffractometry(XRD),X-ray photoelection spectroscopy(XPS),and H2-temperature programmed reduction(TPR)were used to characterize the physicochemical properties of these oxygen carriers.It was confirmed that an interaction between NiO and Fe_(2)O_(3) occurred based on the XPS and H2-TPR results.Based on the CL-ODH activity performance tests conducted in a fixed-bed reactor,it was revealed that ethylene selectivity was significantly improved after NiO addition.Fe_(2)O_(3)-10%NiO/MgO showed the best activity performance with 93%ethane conversion and 50%ethylene selectivity at a reaction temperature of 650℃,atmospheric pressure,and space velocity of 7500 mL/(g·h).

CAL模式在营销策划教学中的应用

营销策划课程的教学目标是培养学生的市场营销实战操作能力。传统教学模式并不利于学生分析和解决问题能力的培养,将CAL教学模式的具体实施步骤和课堂设计运用到营销策划课程教学中,有助于培养学生分析问题和解决问题的能力,同时可以体现营销专业课程教学与企业营销实践相结合的理念。

Techno-economic assessment of a chemical looping splitting system for H2 and CO Co-generation

The natural gas(NG)reforming is currently one of the low-cost methods for hydrogen production.However,the mixture of H2 and CO_(2) in the produced gas inevitably includes CO_(2) and necessitates the costly CO_(2) separation.In this work,a novel double chemical looping involving both combustion(CLC)and sorption-enhanced reforming(SE-CLR)was proposed towards the co-production of H2 and CO(CLC-SECLRHC)in two separated streams.CLC provides reactant CO_(2) and energy to feed SECLRHC,which generates hydrogen in a higher purity,as well as the calcium cycle to generate CO in a higher purity.Techno-economic assessment of the proposed system was conducted to evaluate its efficiency and economic competitiveness.Studies revealed that the optimal molar ratios of oxygen carrier(OC)/NG and steam/NG for reforming were recommended to be 1.7 and 1.0,respectively.The heat integration within CLC and SECLRHC units can be achieved by circulating hot OCs.The desired temperatures of fuel reactor(FR)and reforming reactor(RR)should be 850
C and 600
C,respectively.The heat coupling between CLC and SECLRHC units can be realized via a jacket-type reactor,and the NG split ratio for reforming and combustion was 0.53:0.47.Under the optimal conditions,the H2 purity,the H2 yield and the CH4 conversion efficiency were 98.76%,2.31 mol mol-1 and 97.96%,respectively.The carbon and hydrogen utilization efficiency respectively were 58.60% and 72.45%in terms of the total hydrogen in both steam and NG.The exergy efficiency of the overall process reached 70.28%.In terms of the conventional plant capacity(75 × 103 t y^(-1))and current raw materials price(2500$t^(-1)),the payback period can be 6.2 years and the IRR would be 11.5,demonstrating an economically feasible and risk resistant capability.

Chemical looping oxidative propane dehydrogenation controlled by oxygen bulk diffusion over FeVO_(4)oxygen carrier pellets

The oxygen distribution and evolution within the oxygen carrier exert significant influence on chemical looping processes.This paper describes the influence of oxygen bulk diffusion within FeVO4 oxygen carrier pellets on the chemical looping oxidative propane dehydrogenation(CL-ODH).During CL-ODH,the oxygen concentration at the pellet surface initially decreased and then maintained stable before the final decrease.At the stage with the stable surface oxygen concentration,the reaction showed a stable C3H6 formation rate and high C3H6 selectivity.Therefore,based on Fick’s second law,the oxygen distribution and evolution in the oxygen carrier at this stage were further analyzed.It was found that main reactions of selective oxidation and over-oxidation were controlled by the oxygen bulk diffusion.C3H8 conversion rate kept decreasing during this stage due to the decrease of the oxygen flux caused by the decline of oxygen gradient within the oxygen carrier,while C3H6 selectivity increased due to the decrease of overoxidation.In addition,reaction rates could increase with the propane partial pressure due to the increase of the oxygen gradient within the oxygen carrier until the bulk transfer reached its limit at higher propane partial pressure.This study provides fundamental insights for the diffusion-controlled chemical looping reactions.

Microscopic mechanism study and process optimization of dimethyl carbonate production coupled biomass chemical looping gasification system

Biomass chemical looping gasification technology is one of the essential ways to utilize abundant biomass resources.At the same time,dimethyl carbonate can replace phosgene as an environmentfriendly organic material for the synthesis of polycarbonate.In this paper,a novel system coupling biomass chemical looping gasification with dimethyl carbonate synthesis with methanol as an intermediate is designed through microscopic mechanism analysis and process optimization.Firstly,reactive force field molecular dynamics simulation is performed to explore the reaction mechanism of biomass chemical looping gasification to determine the optimal gasification temperature range.Secondly,steady-state simulations of the process based on molecular dynamics simulation results are carried out to investigate the effects of temperature,steam to biomass ratio,and oxygen carrier to biomass ratio on the syngas yield and compositions.In addition,the main energy indicators of biomass chemical looping gasification process including lower heating value and cold gas efficiency are analyzed based on the above optimum parameters.Then,two synthesis stages are simulated and optimized with the following results obtained:the optimal temperature and pressure of methanol synthesis stage are 150℃ and 4 MPa;the optimal temperature and pressure of dimethyl carbonate synthesis stage are 140℃ and 0.3 MPa.Finally,the pre-separation-extraction-decantation process separates the mixture of dimethyl carbonate and methanol generated in the synthesis stage with 99.11%purity of dimethyl carbonate.Above results verify the feasibility of producing dimethyl carbonate from the perspective of multi-scale simulation and realize the multi-level utilization of biomass resources.

基于单原子铁纳米催化剂的纳米催化疗法对 口腔鳞癌细胞Cal27的作用

目的:制备单原子铁纳米催化剂(single-atom Fe nanocatalysts,SAF NCs),探讨其体外治疗口腔鳞癌的疗效,为口腔鳞癌治疗提供新策略。方法:用隔离与热解结合方法制备SAF NCs,利用透射电镜和球差电镜观察微观形态,X射线衍射图和元素分布能谱分析其结构和成分,溶液层面采用TMB显色实验和电子自旋共振试验检测催化性能,最后通过CCK-8和流式细胞技术、共聚焦显微镜观察体外处理口腔鳞癌Cal27细胞后的活性变化。采用GraphPad Prism 9软件包对数据进行统计学分析。结果:成功合成和表征SAF NCs,在溶液层面显示出优异的催化特性。细胞实验中,SAF NCs显示出良好的生物相容性,在模拟肿瘤微环境特性的条件下,进行体外催化治疗,Cal27细胞活性低至32.08%。结论:初步实验证明,SAF NCs具有良好的生物催化性能,在体外可有效抑制口腔鳞癌细胞增殖,为口腔鳞癌治疗提供了新策略。

大麦芒型突变基因cal-d的遗传定位

芒是麦类作物穂部器官的重要组成部分,在提高籽粒产量、促进种子传播和防御虫害等方面具有重要作用。大麦具有丰富的芒型突变体,加之其二倍体的特性,成为麦类作物芒器官形态建成研究的理想作物。本研究报道了一个大麦芒型突变体材料calcaroides,表现为外稃顶端或是稃芒基部异形凸起,形成呈钩状不完全花器结构,属基部钩芒类型。突变体芒较短并伴随抽穗期推迟,株高、穗长和穗粒数显著降低等表型。遗传分析表明,突变体的芒型突变性状受单隐性基因cal-d控制。前期利用cal-d导入系BW106×Bowman的F_(2)群体,结合简化基因组测序(GBS,genotyping by sequencing)分析,将cal-d基因初步定位于3H染色体。进一步利用来自F_(2)的杂合单株,包括13000株单株的F_(2:3)群体进行精细定位,最终将cal-d基因定位于3H染色体153~329 Mb区间的近着丝粒区域。通过转录组混池测序分析结合大麦基因组和表达谱资源数据库,初步筛选了9个候选基因。本研究结果为大麦芒型突变基因cal-d的克隆与功能验证奠定了基础,对于解析麦类作物芒的遗传发育机制具有重要的意义。

Towards carbon neutrality of calcium carbide-based acetylene production with sustainable biomass resources

Acetylene is produced from the reaction between calcium carbide(CaC_(2))and water,while the production of CaC_(2) generates significant amount of carbon dioxide not only because it is an energy-intensive process but also the raw material for CaC_(2) synthesis is from coal.Here,a comprehensive biomass-to-acetylene process was constructed that integrated several units including biomass pyrolysis,oxygen-thermal CaC_(2) fabrication and calcium looping.For comparison,a coal-to-acetylene process was also established by using coal as feedstock.The carbon efficiency,energy efficiency and environmental impacts of the bio-based calcium carbide acetylene(BCCA)and coal-based calcium carbide acetylene(CCCA)processes were systematically analyzed.Moreover,the environmental impacts were further evaluated by applying thermal integration at system level and energy substitution in CaC_(2) furnace.Even though the BCCA process showed lower carbon efficiency and energy efficiency than that of the CCCA process,life cycle assessment demonstrated the BCCA(1.873 kgCO_(2eq) kg-prod^(-1))a lower carbon footprint process which is 0.366 kgCO_(2eq) kg-prod^(-1) lower compared to the CCCA process.With sustainable energy(biomass power)substitution in CaC_(2) furnace,an even lower GWP value of 1.377 kgCO_(2eq) kg-prod^(-1) can be achieved in BCCA process.This work performed a systematic analysis on integrating biomass into industrial acetylene production,and revealed the positive role of biomass as raw material(carbon)and energy supplier.

新藤黄酸对CAL27细胞裸鼠移植瘤增殖及凋亡作用的研究

目的:探讨新藤黄酸(GNA)对CAL27细胞裸鼠移植瘤增殖及凋亡的影响。方法:将18只SPF级裸鼠随机分为对照组、GNA低剂量组及GNA高剂量组(n=6)。通过接种对数生长期的舌鳞癌CAL27细胞建立皮下裸鼠移植瘤模型,低及高剂量组裸鼠分别隔日静脉注射新藤黄酸8.0 mg/kg与16.0 mg/kg干预,对照组给予等量生理盐水。给药期间绘制肿瘤生长曲线,2周后处死裸鼠并取出肿瘤组织,计算抑瘤率。TUNEL法检测各组裸鼠移植瘤细胞凋亡;免疫组化法检测瘤体组织的AKT、Bcl-2与PI3K蛋白的表达水平;HE染色法检测新藤黄酸对正常组织器官的毒副作用。结果:GNA低及高剂量组裸鼠移植瘤生长缓慢,瘤重及瘤体积明显低于对照组(P<0.05),低和高剂量组抑瘤率分别为57.58%和83.68%。TUNEL结果表明,GNA低及高剂量组凋亡指数高于对照组;免疫组织化学结果表明,GNA低及高剂量组裸鼠肿瘤组织的AKT、Bcl-2及PI3K的表达显著低于对照组(P<0.05)。HE结果显示,GNA对正常组织器官无明显改变。结论:GNA可能通过调控肿瘤组织AKT、Bcl-2及PI3K等蛋白的表达,诱导CAL27细胞凋亡,抑制人舌鳞癌的发生发展,对正常组织器官无明显毒副作用。

斑蝥酸钠对人舌鳞癌CAL27细胞的抑制作用及机制研究

目的:探讨斑蝥酸钠(sodium cantharidate,SCA)对人舌鳞癌CAL27细胞的抑制作用及相关机制。方法:利用不同浓度SCA预处理CAL27细胞后,采用CCK-8法分析细胞活力,划痕实验和Transwell法检测细胞迁移和侵袭能力,流式细胞仪检测细胞凋亡率,Western印迹法检测SCA对CAL27细胞p53及其磷酸化位点Ser33、Ser37、Ser46蛋白、抑凋亡蛋白B淋巴细胞瘤2(BCL-2)、促凋亡蛋白BCL-2相关X蛋白(BAX)和活化半胱氨酸天冬氨酸蛋白酶3(cleaved caspase 3)蛋白表达的影响。采用Graphpad Prism 9.0软件包对数据进行统计学分析。结果:与空白对照组相比,斑蝥酸钠组CAL27细胞增殖、迁移和侵袭能力显著降低,细胞凋亡率显著升高(P<0.01),呈剂量依赖性。随着SCA浓度增加,p53及其磷酸化位点Ser33、37、46蛋白表达显著上调(P<0.05或P<0.01),BCL-2蛋白表达下调,BAX蛋白表达显著上调,BCL-2/BAX比值显著降低,cleaved caspase 3蛋白表达显著上调(P<0.05或P<0.01)。结论:SCA能抑制人舌鳞癌CAL27细胞增殖、迁移和侵袭,并可能通过调控p53蛋白的磷酸化修饰,经BCL-2/BAX-caspase-3信号通路,诱导细胞凋亡。

ADAMTS-7基因rs3825807及rs1994016位点多态性与KD发病及CAL的关联性分析

目的分析ADAMTS-7基因rs3825807、rs1994016位点多态性与川崎病(KD)发病及其冠状动脉损伤(CAL)是否存在关联性。方法选取KD患儿100例为KD组,健康体检儿童100例为健康组。提取两组外周血DNA进行基因测序,比较两组ADAMTS-7基因rs3825807位点及rs1994016位点的多态性差异。KD组根据是否存在冠状动脉损伤分为冠状动脉损伤组(KD-CAL组)和无冠状动脉损伤组(KD-NCAL组),比较两组ADAMTS-7基因rs3825807位点及rs1994016位点的多态性差异。结果KD组与健康组比较,KD-NCAL组与KD-CAL组比较,ADAMTS-7基因rs3825807位点A、G等位基因频率和AA、AG、GG基因型频率以及rs1994016位点C、T等位基因频率和CC、CT、TT基因型频率差异均无统计学意义(P>0.05)。结论ADAMTS-7基因rs3825807、rs1994016位点多态性与KD的发病及CAL不存在明显关联性。

Chemical looping conversion of methane via Fe_(2)O_(3)-LaFeO_(3)calcined from LaFe-MOF precursor

The effective utilization of natural gas resources is a promising option for the implementation of the"dual carbon"strategy.However,the capture of carbon dioxide with relatively lower concentration after the combustion of natural gas is the crucial step.Fortunately,the lattice oxygen is used for chemical cycle conversion of methane to overcome the shortcomings mentioned above.A method was proposed to synthesize perovskite for methane cycle conversion using metal organic framework as a precursor.Morphology and pore structure of Fe_(2)O_(3)-LaFeO_(3)composite oxides were regulated by precursor synthesis conditions and calcination process.Moreover,the chemical looping conversion performance of methane was evaluated.The results showed that the pure phase precursor of La[Fe(CN)_(6)]·5H_(2)O was synthesized with the specific surface area of 23.91 m^(2)·g^(-1)under the crystallization of 10 h and the pH value of10.5.Fe_(2)O_(3)-LaFeO_(3)was obtained by controlled calcination of La[Fe(CN)_(6)]·5H_(2)O and Fe_(2)O_(3)with variable mass ratio.The selectivity of CO_(2)can reach more than 99%under the optimal parameters of methane chemical looping conversion:m(Fe_(2)O_(3)):m(LaFeO_(3))=2:1,the reaction temperature is 900℃,the lattice oxygen conversion is less than 40%.Fe_(2)O_(3)-LaFeO_(3)still has good phase and structure stability after five redox reaction and regeneration cycles.

Gigahertz frequency hopping in an optical phase-locked loop for Raman lasers

Raman lasers are essential in atomic physics,and the development of portable devices has posed requirements for time-division multiplexing of Raman lasers.We demonstrate an innovative gigahertz frequency hopping approach of a slave Raman laser within an optical phase-locked loop(OPLL),which finds practical application in an atomic gravimeter,where the OPLL frequently switches between near-resonance lasers and significantly detuned Raman lasers.The method merges the advantages of rapid and extensive frequency hopping with the OPLL’s inherent low phase noise,and exhibits a versatile range of applications in compact laser systems,promising advancements in portable instruments.