Unveiling of Terahertz Emission from Ultrafast Demagnetization and the Anomalous Hall Effect in a Single Ferromagnetic Film

Using THz emission spectroscopy,we investigate the elementary spin dynamics in ferromagnetic single-layer Fe on a sub-picosecond timescale.We demonstrate that THz radiation changes its polarity with reversal of the magnetization applied by the external magnetic field.In addition,it is found that the sign of THz polarity excited from different sides is defined by the thickness of the Fe layer and Fe/dielectric interface.Based on the thickness and symmetry dependences of THz emission,we experimentally distinguish between the two major contributions:ultrafast demagnetization and the anomalous Hall effect.Our experimental results not only enrich understanding of THz electromagnetic generation induced by femtosecond laser pulses but also provide a practical way to access laser-induced ultrafast spin dynamics in magnetic structures.

Rolling Decision Model of Thermal Power Retrofit and Generation Expansion Planning Considering Carbon Emissions and Power Balance Risk

With the increasing urgency of the carbon emission reduction task,the generation expansion planning process needs to add carbon emission risk constraints,in addition to considering the level of power adequacy.However,methods for quantifying and assessing carbon emissions and operational risks are lacking.It results in excessive carbon emissions and frequent load-shedding on some days,although meeting annual carbon emission reduction targets.First,in response to the above problems,carbon emission and power balance risk assessment indicators and assessment methods,were proposed to quantify electricity abundance and carbon emission risk level of power planning scenarios,considering power supply regulation and renewable energy fluctuation characteristics.Secondly,building on traditional two-tier models for low-carbon power planning,including investment decisions and operational simulations,considering carbon emissions and power balance risks in lower-tier operational simulations,a two-tier rolling model for thermal power retrofit and generation expansion planning was established.The model includes an investment tier and operation assessment tier and makes year-by-year decisions on the number of thermal power units to be retrofitted and the type and capacity of units to be commissioned.Finally,the rationality and validity of the model were verified through an example analysis,a small-scale power supply system in a certain region is taken as an example.The model can significantly reduce the number of days of carbon emissions risk and ensure that the power balance risk is within the safe limit.

Do They Pose a Danger:Evaluation of the Recidivism Characteristics in China’s Community Corrections?

The modern criminal justice system includes community corrections,which play a preventive role in lowering recidivism among offenders.However,some offenders continue to commit crimes during community corrections.This research focuses on community corrections in Chinese community policing practice,particularly offender recidivism.The study collected a total of 500 questionnaires from offenders in the provincial administrative regions of northern China,which included first offense status,psychological status,and recidivism behavior.The study found that most recidivists are usually arrested for“drunk driving”,which may be related to their ability to exercise self-restraint,and that alcohol may contribute to their deviant behavior.Another important finding relates to young recidivists,who may have difficulty securing employment during community corrections and thus use crime again to gain income.In general,this study explores the offender population in Chinese community corrections practice and discusses the factors within it that influence offender recidivism.This may support law enforcement agencies in further evaluating the effectiveness of community corrections,and may provide new information for understanding community corrections in China.

A workfow to Predict the Present-day in-situ Stress Field in Tectonically Stable Regions

Knowledge of the present-day in-situ stress distribution is greatly import-ant for better understanding of conventional and unconventional hydro-carbon reservoirs in many aspects,e.g,reservoir management,wellbore stability asssment,etc.In tectonically stable regions,the present-day in-situ stress field in terms of stress distribution is 1argely controlled by lithological changes,which can be predicted through|a numerical simulation method incorporating specific mechanical properties of the subsurface reservoir.In this study,a workflow was presented to predict the present-day in-situ stress field based on the finite element method(FEM).Sequentially,it consists of:i)building a three-dimensional(3D)geometric framework,i)creating a 3D petrophysical parameter field,11)integrating the geometric framework with petrophysical parameters,iv)setting up a 3D heterogeneous geomechanical model,and finally,v)calculating the present-day in-situ stress distribution and calibrating the prediction with measured stress data,e.g.,results from the extended leak-off tests(XLOTs).The approach was sucessfully applied to the Block W in Ordos Basin of central China.The results indicated that the workflow and models presented in this study could be used as an effective tool to provide insights into stress perturbations in subsurface reservoirs and geological references for subsequent analysis.

基于数学期望的非紧致保正性数值格式

常用的有限差分法、有限元方法和有限体积法等在数值求解偏微分方程时已经非常成功,但在处理各向异性问题时数值格式的保正性还存在一些问题.基于Feynman-Kac公式,可以将抛物方程的解表示为一个条件数学期望,涉及的随机扩散过程对应于抛物方程中的扩散项.不同于常用的紧致Markov链近似,本文用有限个连续分支路径逼近原来的随机过程,在满足相容性精度的条件下计算每个分支的停时(stopping time)、停时发生的概率和停时收益,从而可以逼近条件期望.这样基于数学期望的保正性,对任意的线性抛物型方程设计了一个全新的保正性的线性相容的数值格式,这是一个大时间步长、非紧致的、稳定的显式格式.由于有底层系统的理论支撑,本文的算法能够自适应地区分及处理边界的信息,避免现有算法(如半Lagrange方法)在边界附近精度缺失的问题.

Status and progress of metal-supported solid oxide fuel cell: Towards large-scale manufactory and practical applications

Metal-supported solid oxide fuel cells(MS-SOFCs)own advantages of high performance,fast start-up,thermal cycle stability,easy sealing,and reduced material cost.In recent years,significant progress has been made in the development of MS-SOFCs,particularly with respect to improved electrochemical performance,long-term stability,and industrial production.Previous studies have mainly focused on stainless steel-based MS-SOFCs,with an emphasis on the development of low-temperature preparation processes,antioxidant coatings,stable electrodes,and the direct utilization of hydrocarbon fuels.Notably,Ceres Power and GE have successfully commercialized MS-SOFCs and have constant cooperated with several institutions and companies,such as Jülich Research Center,Weichai and Cummins,to promote the performance and expand the market of MS-SOFC.Looking ahead,this review paper provides an outlook on future research directions in this rapidly evolving field.

Bismuth doped Sr_(2)Fe_(1.5)Mo_(0.5)O_(6-δ) double perovskite as a robust fuel electrode in ceramic oxide cells for direct CO_(2)electrolysis

Electrochemical conversion of CO_(2)to CO is an economically feasible method for mitigating greenhouse gas emissions.Among various electrochemical approaches,solid oxide electrolysis cells(SOECs)show high potential for CO_(2)reduction reaction(CO_(2)-RR)due to their ability to operate at high temperatures,resulting in fast reaction kinetics and increased efficiency.Considering their main energy loss is still associated with the large overpotential at the fuel electrode,the development of the highly efficient and durable cathode for SOECs has been extensively searched after.Here,we propose an A-site doping strategy to enhance the properties of Sr_(2)Fe_(1.5)Mo_(0.5)O_(6−δ)(SFM),which improve its performance as a cathode in SOECs for CO_(2)-RR,demonstrating favorable activity and durability.The structural and physiochemical characterizations,together with DFT calculations,show that the partial replacement of Sr by Bi in the SFM double perovskite not only improves CO_(2) adsorption capability at the catalyst surface but also enhances oxygen ionic conduction inside the bulk oxide,resulting in enhanced CO_(2)electrocatalysis performance in SOECs.Specifically,a La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.2)O_(3−δ) (LSGM)electrolyte-supported single cell with the new Bi-doped SFM cathode demonstrates a large current density of 1620 mA cm^(−2) at a cell potential of 1.6 V at 850°C with good operational stability up to 200 h.Bi-doped SFM thus represents a highly promising cathode for ceramic CO_(2)electrolyzers and could accelerate our transition towards a carbon-neutral society.

Molecular coordination-doping engineering enables adjustable ion transport channel based on MOFs-derived UIOLiTF-LLZTO ionic conductor

The inferior ionic conductivity of composite polymer electrolytes(CPEs)caused by grain boundary impedance is one of the critical issues.Adjustable ion transport channels at the molecular level can improve ionic conductivity and lithium-ion transference number.Herein,UIO-66-NSO_(2)CF_(3)LiLi_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(UIOLiTF-LLZTO)ionic conductor derived from metal-organic frameworks(MOFs)was designed by a covalent grafted strategy of trifluoromethylsulfonyl(TF)group on UIOLiTF and a doping process of LLZTO,showing two new lithium-ion transfer channels driven by molecular coordinationdoping engineering.The first channel along UIOLiTF-UIOLiTF was constructed due to the existence of the TF group on UIOLiTF.The second channel along UIOLiTF-LLZTO was constructed due to the direct nanometer contact interface between the opened channel of UIOLiTF and LLZTO.Then TF group acts as“claws”to capture and transfer lithium-ion along the different channels,facilitating improving ionic conductivity and reducing grain boundary impedance.Benefiting from the molecular coordination-doping engineering,UIOLiTF-LLZTO exhibits high ionic conductivity of 9.86×10^(-4)S cm^(-1),a large lithium-ion transference number of 0.79,and a wide electrochemical window of 5.35 V.Meanwhile,all-solid-state Li|UIOLiTF-LLZTO|LiFePO4 batteries show a high specific capacity of 164.5 mAh g^(-1)and 155.6 mAh g^(-1)at 0.2 C and 0.5 C,respectively.Therefore,UIOLiTF-LLZTO demonstrates the way towards the development of MOFs-based CPEs for all-solid-state lithium batteries with high performance.

高管团队异质性、税收优惠与技术创新——来自2013~2017年制造业上市央企的证据

技术创新是企业的核心成功因素和永恒追求,对中国企业更具有特殊意义。本文采用2013~2017年沪深A股制造业上市央企的专利和财务数据,研究了高管团队异质性和税收优惠对企业技术创新的影响。研究发现,总体上,高管团队身份异质性、工作职能异质性、隐性薪酬差距和税收优惠都与技术创新负相关。进一步分组分析发现,高管团队身份异质性在轻工业与非高新技术产业领域具有显著负向影响,而工作职能异质性的显著负影响体现在重工业与高新技术产业领域,且仅在东部地区成立,在中、西部地区不成立。行业分组和区域分组后,隐性薪酬差距的影响不再确定。税收优惠与技术创新在行业和区域分组后仍然负相关。影响作用由高到低依次为高管团队身份异质性、工作职能异质性、税收优惠和隐性薪酬差距。前期超额实质性创新对后期实质性创新产出具有决定性促进作用,前期超额策略性创新对后期技术创新总产出和策略性创新产出具有决定性促进作用,但对后期实质性创新产出没有促进作用。

Root microbiota shift in rice correlates with resident time in the field and developmental stage

Land plants in natural soil form intimate relationships with the diverse root bacterial microbiota. A growing body of evidence shows that these microbes are important for plant growth and health. Root microbiota composition has been widely studied in several model plants and crops; however, little is known about how root microbiota vary throughout the plant's life cycle under field conditions. We performed longitudinal dense sampling in field trials to track the time-series shift of the root microbiota from two representative rice cultivars in two separate locations in China. We found that the rice root microbiota varied dramatically during the vegetative stages and stabilized from the beginning of the reproductive stage, after which the root microbiota underwent relatively minor changes until rice ripening. Notably, both rice genotype and geographical location influenced the patterns of root microbiota shift that occurred during plant growth. The relative abundance of Deltaproteobacteria in roots significantly increased overtime throughout the entire life cycle of rice, while that of Betaproteobacteria, Firmicutes, and Gammaproteobacteria decreased. By a machine learning approach, we identified biomarker taxa and established a model to correlate root microbiota with rice resident time in the field(e.g., Nitrospira accumulated from 5 weeks/tillering in field-grown rice). Our work provides insights into the process of rice root microbiota establishment.

Effects of tourmaline on nitrogen removal performance and biofilm structures in the sequencing batch biofilm reactor

The effects of tourmaline on nitrogen removal performance and biofilm structures were comparatively investigated in two identical laboratory-scale sequencing batch biofilm reactors（SBBRs）（denoted SBBR1 and SBBR2） at different nitrogen loading rates（NLRs） varying from（0.24 ± 0.01） to（1.26 ± 0.02） g N/（L·day）. SBBR1 was operated in parallel with SBBR2, but SBBR1 was filled with polyurethane foam loaded tourmaline（TPU） carriers and another（SBBR2） filled with polyurethane foam（PU） carriers. Results obtained from this study showed that the excellent and stable performance of SBBR1 was obtained. Ammonia nitrogen removal and total nitrogen removal were higher in SBBR1 than that in SBBR2 with increase of NLR. At an NLR of（0.24 ± 0.01） g N/（L·day）, the majority of the spherical and elliptical bacteria were surrounded by the extracellular polymeric substance（EPS） and bacillus or filamentous bacteria in two SBBRs biofilms. When NLR increased to（1.26 ± 0.02） g N/（L·day）, the clusters were more obvious in the SBBR1 biofilm than that in the SBBR2 biofilm. Bacteria in SBBR1 were inclined to synthesis more EPS, and the formed EPS could protect the bacteria from free ammonia（FA） under extreme condition NLR（1.26 ± 0.02） g N/（L·day）. The results of polymerase chain reaction-denaturing gradient gel electrophoresis analysis showed that the microbial community similarity in SBBR2 decreased more obviously than that in SBBR1 with the increase of NLR, which the microbial community in SBBR1 was relatively stable.

The rice histone methylation regulates hub species of the root microbiota

Plants have a close relationship with their root microbiota,which comprises a complex microbial network.Histone methylation is an important epigenetic modification influencing multiple plant traits;however,little is known about the role of plant histone methylation in the assembly and network structure of the root microbiota.In this study,we established that the rice(Oryza sativa)histone methylation regulates the structure and composition of the root microbiota,especially the hub species in the microbial network.DJjmj703(defective in histone H3K4 demethylation)and ZH11-sdg714(defective in H3K9 methylation)showed significant different root microbiota compared with the corresponding wild types at the phylum and family levels,with a consistent increase in the abundance of Betaproteobacteria and a decrease in the Firmicutes.In the root microbial network,35 of 44 hub species in the top 10 modules in the tested field were regulated by at least one histone methylation-related gene.These observations establish that the rice histone methylation plays a pivotal role in regulating the assembly of the root microbiota,providing insights into the links between plant epigenetic regulation and root microbiota.

Modelling of finger-like channelled anode support for SOFCs application

This paper established a numerical model for a solid oxide fuel cell(SOFC) button cell,focusing on the effects of finger-like channels on the gas transport process in the anode support.The current densities of channelled button cell and un-channelled button cell are compared at different operating temperature and voltage with H_2 as the fuel.The H_2 transport is discussed in detail,such as the mole fraction distribution of H_2 in the porous layer,the diffusion flux and convective flux of H_2.It is found that the performance of SOFC can be improved by 2.60%at 800℃,0.5 V,compared with un-channelled SOFC due to the improved gas transport by the finger-like channels.Then,the model is further extended to study 2D-planar SOFC fuelled with syngas.The mole fraction gradients of Hv2,CO,CH_4 and CO are all substantially reduced by the finger-like channels compared to un-channelled planar cell.It is found that the SOFC performance is improved by 5.93%at 800 ℃,0.5 V,when syngas fuel is used.The present study clearly demonstrated that the use of finger-like channels in the anode support is effective in improving the gas transport and the SOFC performance.The present model can be employed for subsequent optimization of the channel configuration for further performance improvement.

Naturally occurring spike mutations influence the infectivity and immunogenicity of SARS-CoV-2

Mutations in SARS-CoV-2 variants of concern(VOCs)have enhanced transmissibility and immune evasion with respect to current vaccines and neutralizing antibodies(NAbs).How naturally occurring spike mutations affect the infectivity and antigenicity of VOCs remains to be investigated.The entry efficiency of individual spike mutations was determined in vitro using pseudotyped viruses.BALB/c mice were immunized with 2-dose DNA vaccines encoding B.1.1.7,B.1.351,B.1.1.529 and their single mutations.Cellular and humoral immune responses were then compared to determine the impact of individual mutations on immunogenicity.In the B.1.1.7 lineage,Del69–70 and Del 144 in NTD,A570D and P681H in SD1 and S982A and D1118H in S2 significantly increased viral entry,whereas T716I resulted in a decrease.In the B.1.351 lineage,L18F and Del 242–244 in the NTD,K417N in the RBD and A701V in S2 also increased viral entry.S982A weakened the generation of binding antibodies.All sera showed reduced cross-neutralization activity against B.1.351,B.1.617.2(Delta)and B.1.1.529(Omicron BA.1).S982A,L18F,and Del 242–244 hindered the induction of cross-NAbs,whereas Del 69–70,Del144,R246I,and K417N showed the opposite effects.B.1.351 elicited adequate broad cross-NAbs against both B.1.351 and B.1.617.2.All immunogens tested,however,showed low neutralization against circulating B.1.1.529.In addition,T-cell responses were unlikely affected by mutations tested in the spike.We conclude that individual spike mutations influence viral infectivity and vaccine immunogenicity.Designing VOC-targeted vaccines is likely necessary to overcome immune evasion from current vaccines and neutralizing antibodies.

In-situ deposition of Pd/Pd_(4)S heterostructure on hollow carbon spheres as efficient electrocatalysts for rechargeable Li-O_(2)batteries

The sluggish kinetics of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)have always restricted the development of lithium oxygen batteries(LOBs).Herein,hollow carbon spheres loaded with Pd/Pd_(4)S heterostructure(Pd/Pd_(4)S@HCS)were successfully prepared via the in-situ deposition to improve the electrocatalytic activities for both ORR and OER in LOBs.With the welldispersed Pd/Pd_(4)S nanoparticles,the hierarchical composite with large specific surface area offers favorable transport channels for ions,electron and oxygen.Especially,the Pd/Pd_(4)S nanoparticles could exhibit excellent electrochemical performance for ORR and OER due to their intrinsic catalytic property and interfacial effect from the heterostructure.Therefore,the LOBs with Pd/Pd_(4)S@HCS as cathode catalyst show improved specific capacities,good rate ability and stable cycling performance.

Co-delivery of luteolin and TGF-β1 plasmids with ROS-responsive virus-inspired nanoparticles for microenvironment regulation and chemo-gene therapy of intervertebral disc degeneration

Intervertebral disc degeneration(IDD)is closely related to inflammation and imbalance of synthesis/catabolism of extracellular matrix(ECM)in intervertebral disc(IVD).Considering this,luteolin(LUT),a kind of natural flavonoid with good anti-inflammatory effect and TGF-β1(a gene that promotes the regeneration of ECM)plasmid was co-loaded and co-delivered to nucleus pulposus cells(NPCs).Reactive oxygen species(ROS)responsive cationic copolymer,poly(β-amino ester)-poly(ε-caprolactone)(PBC),with high plasmid DNA(pDNA)compression affinity was synthesized.It can self-assemble into nano-sized polyplexes(pDNA@PBC)with virus-inspired structure and function through which it can transfect pDNA into NPCs with very high efficiency and negligible cytotoxicity.LUT was encapsulated in the hydrophobic core of pDNA@PBC.The co-delivery system,LUT-pTGFβ1@PBC,could enhance the cellular uptake of NPCs and manifest excellent sustained drug release in IVD.Real time quantitative polymerase chain reaction(RT-qPCR)and Western blot experiments reveal that the co-delivery system could inhibit inflammation in NPCs and restore the balance of anabolism and catabolism in vitro by activating TGF/SMAD3 and inhibiting NFkB/p65.Moreover,LUT-pTGF-β1@PBC retards IDD in vivo as detected by radiological and histological methods with good biosafety in rats.LUT-pTGF-β1@PBC may be a promising option for the treatment of IDD.

Prediction of natural fracture in shale oil reservoir based on R/S analysis and conventional logs

Investigation into natural fractures is extremely important for the exploration and development of low-permeability reservoirs.Previous studies have proven that abundant oil resources are present in the Upper Triassic Yanchang Formation Chang 7 oil-bearing layer of the Ordos Basin,which are accumulated in typical low-permeability shale reservoirs.Natural fractures are important storage spaces and flow pathways for shale oil.In this study,characteristics of natural fractures in the Chang 7 oil-bearing layer are first analyzed.The results indicate that most fractures are shear fractures in the Heshui region,which are characterized by high-angle,unfilled,and ENE-WSW-trending strike.Subsequently,natural fracture distributions in the Yanchang Formation Chang 7 oil-bearing layer of the study area are predicted based on the R/S analysis approach.Logs of AC,CAL,ILD,LL8,and DEN are selected and used for fracture prediction in this study,and the R(n)/S(n)curves of each log are calculated.The quadratic derivatives are calculated to identify the concave points in the R(n)/S(n)curve,indicating the location where natural fracture develops.Considering the difference in sensitivity of each log to natural fracture,gray prediction analysis is used to construct a new parameter,fracture prediction indicator K,to quantitatively predict fracture development.In addition,fracture development among different wells is compared.The results show that parameter K responds well to fracture development.Some minor errors may probably be caused by the heterogeneity of the reservoir,limitation of core range and fracture size,dip angle,filling minerals,etc.

Towards online optimisation of solid oxide fuel cell performance: Combining deep learning with multi-physics simulation

The use of solid oxide fuel cells(SOFCs)is a promising approach towards achieving sustainable electricity pro-duction from fuel.The utilisation of the hydrocarbons and biomass in SOFCs is particularly attractive owing to their wide distribution,high energy density,and low price.The long-term operation of SOFCs using such fuels remains difficult owing to a lack of an effective diagnosis and optimisation system,which requires not only a precise analysis but also a fast response.In this study,we developed a hybrid model for an on-line analysis of SOFCs at the cell level.The model combines a multi-physics simulation(MPS)and deep learning,overcoming the complexity of MPS for a model-based control system,and reducing the cost of building a database(compared with the experiments)for the training of a deep neural network.The maximum temperature gradient and heat generation are two target parameters for an efficient operation of SOFCs.The results show that a precise predic-tion can be achieved from a trained AI algorithm,in which the relative error between the MPS and AI models is less than 1%.Moreover,an online optimisation is realised using a genetic algorithm,achieving the maximum power density within the limitations of the temperature gradient and operating conditions.This method can also be applied to the prediction and optimisation of other non-liner,dynamic systems.

国际贸易摩擦与审计师行为——来自审计费用的证据

近年来,国际贸易摩擦频繁发生,对经济发展和企业进出口都产生了重大影响。本文将研究视角聚焦于审计师行为,探讨国际贸易摩擦是否以及如何影响上市公司的审计费用水平。研究发现,企业遭受贸易摩擦冲击以后,审计费用水平明显提高。在采用平行趋势检验、PSM配对、安慰剂测试等一系列稳健性检验后,这一结论依然成立。进一步的机制检验发现,贸易摩擦增大了企业的经营风险,提高了企业的盈余管理程度,并且促使审计师在工作时付出更多努力,进而提高了审计费用水平。最后,异质性检验发现,对于国际四大会计师事务所,贸易摩擦对审计费用的影响明显强化;但是当上市公司是会计师事务所的重要客户时,贸易摩擦对审计费用的影响显著弱化。本文从审计师行为视角揭示了国际贸易摩擦的微观经济后果,相关结论对于企业和有关部门均具有重要的借鉴意义。