新能源汽车产业创新能力如何影响财务绩效——基于中国上市公司的实证分析

本文基于中国第十四个五年规划和2035年远景目标纲要,以2016-2020年中国沪深A股上市公司为研究样本,检验新能源汽车产业创新能力对财务绩效的影响。研究发现,新能源汽车产业上市公司在技术、管理、知识三个维度上显著提升财务绩效,且经过一系列稳健性检验和内生性处理后该结论仍然稳健。进一步分析发现,较高的风险承担能力有助于研发创新进而提升企业绩效,创新能力对企业财务绩效的激励作用在国有和非国有车企中并无差异,但国企背景下新能源汽车产业上市公司的管理创新能力对财务绩效的正效应更显著,而在非国企背景下技术创新能力和知识创新能力的提升对财务绩效的促进作用更强。机制检验表明,创新能力可以通过提升企业核心竞争力对财务绩效产生促进作用。经济后果检验表明,财务绩效在创新能力与企业生产效率间有正向经济作用。本文从企业创新能力的新维度,为提升新能源汽车产业公司财务绩效、推进创新能力发展提供了理论支持和经验证据。

Multi-branched AgAuPt nanoparticles for efficient electrocatalytic hydrogen evolution:Synergism of tip-enhanced electric field effect and local electric field effect

High-curvature multi-noble metallic heterostructures can effectively enhance the electrocatalytic hydrogen evolution performance by utilizing the synergism of tip-enhanced electric field effect and local electric field effect.Herein,we report a two-step synthesis strategy to obtain multi-branched high-curvature Ag Au Pt heterostructure,firstly amino acids-induced growth of Au branches on Ag nanocubes,and secondly L-AA reduction of H_(2)PtCl_(6) to incorporate tiny Pt nanoparticles on Au branches.The D-CAgAuPt results in a low overpotential of 38 m V to deliver a cathodic current density of 10 m A cm^(-2),which is superior to commercial 20%Pt/C(46 m V).The strong electronic interactions between multi-noble metals intrinsically enhance the durability and stability of the catalysts.The intrinsic mechanism of promoting HER performance is investigated and revealed in-depth via the FDTD simulations and DFT calculations.In addition,D-CAg Au Pt can also achieve efficient and stable hydrogen evolution in a proton exchange membrane electrolyzer,which has the potential for commercial practical application.This work designs a novel multi-branched high-curvature multi-noble metallic heterostructure,and fully provides insights into the generical and efficient enhancement of electrocatalytic HER performance of multi-noble metallic heterostructures.

High efficient Raman sideband cooling and strong three-body recombination of atoms

We report a highly efficient three-dimensional degenerated Raman sideband cooling(3D dRSC)that enhances the loading of a magnetically levitated optical dipole trap,and observe the strong atom loss due to the three-body recombination.The 3D dRSC is implemented to obtain 5×10^(7)Cs atoms with the temperature of~480 nK.The cold temperature enables 1.8×10^(7)atoms loaded into a crossed dipole trap with an optimized excessive levitation magnetic gradient.Compared to the loading of atoms from a bare magneto-optical trap or the gray-molasses cooling,there is a significant increase in the number of atoms loaded into the optical dipole trap.We derive for the three-body recombination coefficient of L_(3)=7.73×10^(-25)cm^(6)/s by analyzing the strong atom loss at a large scattering length of 1418 Bohr radius,and discover the transition from the strong three-body loss to the dominant one-body loss.Our result indicates that the lifetime of atoms in the optical dipole trap is finally decided by the one-body loss after the initial strong three-body loss.

Improved design of online fault diagnoser for partially observed Petri nets with generalized mutual exclusion constraints

This paper investigates the fault detection problem for discrete event systems (DESs) which can be modeled by partially observed Petri nets (POPNs). To overcome the problem of low diagnosability in the POPN online fault diagnoser in current use, an improved online fault diagnosis algorithm that integrates generalized mutual exclusion constraints (GMECs) and integer linear programming (ILP) is proposed. Assume that the POPN structure and its initial markings are known, and the faults are modeled as unobservable transitions. First, the event sequence is observed and recorded. GMEC is used for elementary diagnosis of the system behavior, then the ILP problem of POPN is solved for further diagnosis. Finally, an example of a real DES to test the new fault diagnoser is analyzed. The proposed algorithm increases the diagnosability of the DES remarkably, and the effectiveness of the new algorithm integrating GMEC and ILP is verified.

Particulate Amines in the Background Atmosphere of the Yangtze River Delta,China:Concentration,Size Distribution,and Sources

Amines are important for new particle formation and subsequent growth in the atmosphere.Consequently,the processes involved are receiving more attention in recent years.Here,we conduct a field observation in order to investigate the atmospheric particulate amines at a background site in the Yangtze River Delta(YRD)during the summer of 2018.Four amines in PM_(2.5),i.e.,methylamine(MA),dimethylamine(DMA),diethylamine(DEA),and trimethylamine(TMA),were collected,twice daily and analyzed.During the campaign,our measurements found the concentrations of MA,DMA,DEA,and TMA of 15.0±15.0,6.3±6.9,20.4±30.1,and 4.0±5.9 ng m^-(3),respectively,and the four amines correlated well with each other.The concentration of amines appear to be independent of whether they were collected during the day or night.Both MA and DMA exhibited a bimodal size distribution that had peaks at 0.67 and 1.1μm,suggesting amines preferably distribute on submicron particles.Boundary layer height(BLH),relative humidity,and pH of aerosols were found have a negative relationship with amines,while aerosol liquid water content(ALWC)was found to have a positive relationship with amines.The PMF(positive matrix factorization)source apportionment results showed that the main source of amines in Chongming Island was of anthropogenic origin such as industrial and biomass emission,followed by marine sources including sea salt and marine biogenic sources.Given that the YRD region is still suffering from complex atmospheric pollution and that the knowledge on aerosol amines is still limited,more field studies are in urgent need for a better understanding of the pollution characteristics of amines.

Superfluid to Mott-insulator transition in a one-dimensional optical lattice

Bose–Einstein condensates(BEC)of sodium atoms are transferred into one-dimensional(1D)optical lattice potentials,formed by two laser beams with a wavelength of 1064 nm,in a shallow optical trap.The phase coherence of the condensate in the lattice potential is studied by changing the lattice depth.A qualitative change in behavior of the BEC is observed at a lattice depth of~13.7Er,where the quantum gas undergoes a transition from a superfluid state to a state that lacks well-to-well phase coherence.

Spin current in a spinor Bose–Einstein condensate induced by a gradient magnetic field

We develop a research of spin currents in a^(23)Na spinor Bose–Einstein condensate(BEC)by applying a magnetic field gradient.The spin current is successfully induced by the spin-dependent force arising from the magnetic field gradient.The dynamics of the spin components under the magnetic force is investigated.The study is promising to be extended to produce a longer spin-coherence and to enhance the sensitivity of the spin-mixing interferometry in a spinor BEC.

手性等离子体核壳纳米结构的设计及应用

手性描述了一个物体不能与其镜像重叠的几何性质,自19世纪以来一直是化学和生物学中的一个关键概念。随着纳米技术的发展,手性等离子体纳米材料凭借其特殊的手性光学性质和良好的生物相容性已经成为科学家们的研究重点和手性功能材料开发的热点。然而,较弱的手性响应信号限制了其应用和发展。将手性等离子体纳米材料和核壳结构结合得到的手性等离子体核壳纳米结构是一种放大手性响应信号的有效策略。核壳纳米结构整合了内外两种材料的性质,互相补充各自的不足,能够进一步改善材料的物理化学性质,提升材料在各个领域的性能。本文依据手性分子的空间分布对手性等离子体核壳纳米结构的设计策略进行了总结,并综述了其在超灵敏传感和手性催化领域的应用,分析了目前尚存在的问题和可能的解决方式,对其未来的发展作了进一步展望。

Generation of coherent blue light via bichromatic pumping in cesium vapor

Diode-pumped alkali lasers,possessing high efficiency and narrow linewidth,can provide feasible solutions for wavelength ranges difficult to reach by commercial lasers.In this study,we investigate a generation of coherent blue light(CBL)via four-wave mixing(FWM)-based up-conversion processes in cesium(Cs)vapor.A bichromatic pumping scheme with 852-and 917-nm lasers drives the Cs atoms to the 6D5/2 excited level,followed by cascaded decay of 6D5/2→7 P3/2→6 S1/2,producing 456-nm CBL under phase matching conditions.The fluorescence in multiple bands from blue to near-and far-infrared in the FWM process is demonstrated under different experimental conditions.To optimize the experimental parameters,we investigate the dependence of 456-nm CBL on the vapor temperature,frequency,and intensity of the two pump lasers.A maximum power of 2.94 mW is achieved with pump powers of 430 mW(for 852 nm)and 470 mW(for 917 nm).The corresponding conversion efficiency is 1.5%/W,three-fold higher than those in previous studies.Our results can contribute to fundamental research on atom–photon interactions and quantum metrology.

Object-based image analysis of suburban landscapes using Landsat-8 imagery

Many experiments of object-based image analysis have been conducted in remote sensing classification.However,they commonly used highresolution imagery and rarely focused on suburban area.In this research,with the Landsat-8 imagery,classification of a suburban area via the object-based approach is achieved using four classifiers,including decision tree(DT),support vector machine(SVM),random trees(RT),and naive Bayes(NB).We performed feature selection at different sizes of segmentation scale and evaluated the effects of segmentation and tuning parameters within each classifier on classification accuracy.The results showed that the influence of shape on overall accuracy was greater than that of compactness,and a relatively low value of shape should be set with increasing scale size.For DT,the optimal maximum depth usually varied from 5 to 8.For SVM,the optimal gamma was less than or equal to 10^(-2),and its optimal C was greater than or equal to 10^(2).For RT,the optimal active variables was less than or equal to 4,and the optimal maximum tree number was greater than or equal to 30.Furthermore,although there was no statistically significant difference between some classification results produced using different classifiers,SVM has a slightly better performance.

Atom-optically synthetic gauge fields for a noninteracting Bose gas

Synthetic gauge fields in synthetic dimensions are now of great interest.This concept provides a convenient manner for exploring topological phases of matter.Here,we report on the first experimental realization of an atom-optically synthetic gauge field based on the synthetic momentum-state lattice of a Bose gas of ^(133)Cs atoms,where magnetically controlled Feshbach resonance is used to tune the interacting lattice into noninteracting regime.Specifically,we engineer a noninteracting one-dimensional lattice into a two-leg ladder with tunable synthetic gauge fields.We observe the flux-dependent populations of atoms and measure the gauge field-induced chiral currents in the two legs.We also show that an inhomogeneous gauge field could control the atomic transport in the ladder.Our results lay the groundwork for using a clean noninteracting synthetic momentum-state lattice to study the gauge field-induced topological physics.

Wide and fast-frequency tuning for a stabilized diode laser

External-cavity diode laser(ECDL)has important applications in many fundamental and applied researches.Here we report a method to fast and widely tune the frequency of a stabilized ECDL.The beat frequency between the ECDL and a frequency-locked reference laser is identified by the voltagecontrolled oscillator contained in a phase detector,whose output voltage is subtracted from the flexibly controlled PC signal to generate an error signal for stabilizing the ECDL.The output frequency of the stabilized ECDL can be shifted at a short characteristic time of∼150µs within a range of∼620 MHz.The wide and fast-frequency tuning achieved by our method is compared with other previous works.We demonstrated the performance of our method by the efficient sub-Doppler cooling of Cs atoms with the temperature as low as 6µK.

IL4I1-driven AHR signature: a new avenue for cancer therapy

Aryl hydrocarbon receptor(AHR)was considered to be an important pan-tumor therapeutic target,but small molecule inhibitors targeting AHR target gene ID01 have failed in clinical trials.The recent paper published in Cell by Opitz et al.explained the failure of previous clinical trials and identified new therapeutic targets(Fig.1).