人工智能能否赋能区域技术创新——创新环境的中介效应

为探究人工智能是否对提升技术创新水平具有赋能效应,基于2011—2020年30个省级行政区面板数据,运用双向固定效应模型和中介效应模型,实证分析人工智能对技术创新的影响以及创新环境的中介效应。基准回归结果表明,人工智能能够显著赋能技术创新水平提升。中介效应检验结果表明,创新环境在人工智能赋能技术创新的过程中发挥部分中介作用,人工智能有助于优化创新环境,聚集人才并吸引投资,从而促进技术创新水平提升。异质性分析结果表明,对于经济发展水平越高、技术越密集的地区,人工智能赋能技术创新水平提升的作用越明显,区域间发展差距较大;对于3种不同创新类型,人工智能均表现出显著促进效应,对发明专利、实用新型专利和外观设计专利的促进作用呈现由低到高的特点。非线性分析结果表明,人工智能赋能技术创新整体呈现边际效应递减趋势。

黏粒含量及含水比对红黏土强度特性的影响

【目的】为了研究不同黏粒含量及不同含水比对红黏土强度特性的影响,【方法】以桂林市红黏土为研究对象,根据净水沉降原理从所取红黏土中提取黏粒,以制备不同黏粒掺量的红黏土试样,进行固结不排水三轴试验,对不同黏粒含量及不同含水比红黏土强度指标、应力-应变关系进行分析。【结果】结果显示:随着黏粒掺量的增加,红黏土的黏聚力从30.57~37.71 kPa增加至43.36~59.66 kPa,而内摩擦角从18.0°~22.0°减少至14.5°~15.5°;随着含水比的增加,红黏土的黏聚力从37.71~59.66 kPa减少至30.57~43.36 kPa,而内摩擦角从14.5°~18.0°增加至15.5°~22.0°。【结论】结果表明:黏粒含量和含水比对红黏土的黏聚力和内摩擦角的影响明显,随着黏粒的不断添加,黏聚力会不断上升,内摩擦角会不断减小,但随着含水比的增大,黏聚力呈线性减小,内摩擦角呈线性增加,黏粒含量较含水比对黏聚力和内摩擦角的影响更为显著;黏粒含量和含水比对红黏土应力-应变关系曲线的影响基本属于硬化型,黏粒含量越大,硬化性越好,含水比越大,土体的主应力差越小,但土体的硬化性保存不变。可见,红黏土的抗剪强度指标受黏粒含量和含水比的影响明显。

Internal electric field modulation by copper vacancy concentration of cuprous sulfide nanosheets for enhanced selective CO_(2) photoreduction

Although the internal electric field(IEF)of photocatalysts is acknowledged as a potent driving force for photocharge separation,modulating the IEF intensity to achieve enhanced photocatalytic performances remains a challenge.Herein,cuprous sulfide nanosheets with different Cu vacancy concentration were employed to study IEF modulation and corresponding direct charge transfer.Among the samples,Cu_(1.8)S nanosheets possessed intensified IEF intensity compared with those of Cu_(2)S and Cu_(1.95)S nanosheets,suggesting that an enhanced IEF intensity could be achieved by introducing more Cu vacancies.This intensified IEF of Cu_(1.8)S nanosheets induced numerous photogenerated electrons to migrate to its surface,and the dissociative electrons were then captured by Cu vacancies,resulting in efficient charge separation spatially.In addition,the Cu vacancies on Cu_(1.8)S nanosheets accumulated electrons as active sites to lower the energy barrier of rate-determining step of CO_(2)photoreduction,leading to the selective conversion of CO_(2)to CO.Herein,the manipulation of IEF intensity through Cu vacancy concentration regulation of cuprous sulfide photocatalysts for efficient charge separation has been discussed,providing a scientific strategy to rationally improve photocata lytic performances for solar energy conversion.

Highly Efficient Broadband Achromatic Microlens Design Based on Low-Dispersion Materials

Metalenses with achromatic performance offer a new opportunity for high-quality imaging with an ultracompact configuration;however,they suffer from complex fabrication processes and low focusing efficiency.In this study,we propose an efficient design method for achromatic microlenses on a wavelength scale using materials with low dispersion,an adequately designed convex surface,and a thickness profile distribution.By taking into account the absolute chromatic aberration,relative focal length shift(FLS),and numerical aperture(NA),microlens with a certain focal length can be realized through our realized map of geometric features.Accordingly,the designed achromatic microlenses with low-dispersion fused silica were fabricated using a focused ion beam,and precise surface profiles were obtained.The fabricated microlenses exhibited a high average focusing efficiency of 65%at visible wavelengths of 410-680 nm and excellent achromatic capability via white light imaging.Moreover,the design exhibited the advantages of being polarization-insensitive and near-diffraction-limited.These results demonstrate the effectiveness of our proposed achromatic microlens design approach,which expands the prospects of miniaturized optics such as virtual and augmented reality,ultracompact microscopes,and biological endoscopy.

Dynamic Multi-Physics Behaviors and Performance Loss of Cylindrical Batteries Upon Low-Velocity Impact Loading

In challenging operational environments,Lithium-ion batteries(LIBs)inevitably experience mechanical stresses,including impacts and extrusion,which can lead to battery damage,failure,and even the occurrence of fire and explosion incidents.Consequently,it is imperative to investigate the safety performance of LIBs under mechanical loads.This study is grounded in a more realistic coupling scenario consisting of electrochemical cycling and low-velocity impact.We systematically and experimentally uncovered the mechanical,electrochemical,and thermal responses,damage behavior,and corresponding mechanisms under various conditions.Our study demonstrates that higher impact energy results in increased structural stiffness,maximum temperature,and maximum voltage drop.Furthermore,heightened impact energy significantly influences the electrical resistance parameters within the internal resistance.We also examined the effects of State of Charge(SOC)and C-rates.The methodology and experimental findings will offer insights for enhancing the safety design,conducting risk assessments,and enabling the cascading utilization of energy storage systems based on LIBs.

A Review on Engineering Transition Metal Compound Catalysts to Accelerate the Redox Kinetics of Sulfur Cathodes for Lithium–Sulfur Batteries

Engineering transition metal compounds(TMCs)catalysts with excellent adsorption-catalytic ability has been one of the most effec-tive strategies to accelerate the redox kinetics of sulfur cathodes.Herein,this review focuses on engineering TMCs catalysts by cation doping/anion doping/dual doping,bimetallic/bi-anionic TMCs,and TMCs-based heterostructure composites.It is obvious that introducing cations/anions to TMCs or constructing heterostructure can boost adsorption-catalytic capacity by regulating the electronic structure including energy band,d/p-band center,electron filling,and valence state.Moreover,the elec-tronic structure of doped/dual-ionic TMCs are adjusted by inducing ions with different electronegativity,electron filling,and ion radius,resulting in electron redistribution,bonds reconstruction,induced vacancies due to the electronic interaction and changed crystal structure such as lat-tice spacing and lattice distortion.Different from the aforementioned two strategies,heterostructures are constructed by two types of TMCs with different Fermi energy levels,which causes built-in electric field and electrons transfer through the interface,and induces electron redistribution and arranged local atoms to regulate the electronic structure.Additionally,the lacking studies of the three strategies to comprehensively regulate electronic structure for improving catalytic performance are pointed out.It is believed that this review can guide the design of advanced TMCs catalysts for boosting redox of lithium sulfur batteries.

Nonreciprocal thermal metamaterials:Methods and applications

Nonreciprocity of thermal metamaterials has significant application prospects in isolation protection,unidirectional transmission,and energy harvesting.However,due to the inherent isotropic diffusion law of heat flow,it is extremely difficult to achieve nonreciprocity of heat transfer.This review presents the recent developments in thermal nonreciprocity and explores the fundamental theories,which underpin the design of nonreciprocal thermal metamaterials,i.e.,the Onsager reciprocity theorem.Next,three methods for achieving nonreciprocal metamaterials in the thermal field are elucidated,namely,nonlinearity,spatiotemporal modulation,and angular momentum bias,and the applications of nonreciprocal thermal metamaterials are outlined.We also discuss nonreciprocal thermal radiation.Moreover,the potential applications of nonreciprocity to other Laplacian physical fields are discussed.Finally,the prospects for advancing nonreciprocal thermal metamaterials are highlighted,including developments in device design and manufacturing techniques and machine learning-assisted material design.

Vacancy healing for stable perovskite solar cells via bifunctional potassium tartrate

Perovskite solar cell has gained widespread attention as a promising technology for renewable energy.However, their commercial viability has been hampered by their long-term stability and potential Pb leakage. Herein, we demonstrate a bifunctional passivator of the potassium tartrate(PT) to address both challenges. PT minimizes the Pb leakage in perovskites and also heals cationic vacancy defects, resulting in improved device performance and stability. Benefiting from PT modification, the power conversion efficiency(PCE) is improved to 23.26% and the Pb leakage in unencapsulated films is significantly reduced to 9.79 ppm. Furthermore, the corresponding device exhibits no significant decay in PCE after tracking at the maximum power point(MPP) for 2000 h under illumination(LED source, 100 mW cm^(-2)).

黏粒含量对红黏土强度、崩解性及渗透性的影响研究

为了研究黏粒含量对红黏土强度、崩解及渗透性质的影响,以桂林红黏土为研究对象,分别进行不同黏粒含量红黏土(黏粒含量分别为42.37%,47.37%,52.37%和57.37%)的三轴压缩试验、崩解试验和变水头渗透试验,对不同黏粒含量红黏土的应力-应变曲线、抗剪强度指标、崩解现象、渗透系数进行分析。试验结果表明:不同黏粒含量红黏土的应力-应变曲线均为应变软化型;随着黏粒含量的增加,红黏土的黏聚力不断增大,内摩擦角不断减小;不同黏粒含量红黏土崩解时间-崩解量曲线均表现为“S”型特征;随着黏粒含量的增加,红黏土的崩解时间逐渐增长,而渗透系数逐渐减小。分析认为土中的黏粒增加会增强土颗粒之间的黏结作用,黏粒以不同的形式填充土体内部的孔隙和裂隙,减小土体颗粒之间的摩擦,一定程度上堵塞水体流动通道,降低水体在土中的渗透作用。整体来看,黏粒可以增强红黏土的水稳定性和抗渗能力,对抗剪强度指标影响显著。上述研究成果可以为红黏土地区的工程建设和红黏土改良提供参考。

Design and application of an autonomous Master Control System for a multi-layer magnetic and helioseismic telescope

With the growing significance of space weather forecasting,multi-layer magnetic and helioseismic telescopes are emerging as a key area of research.However,owing to the diverse operational processes and sophisticated hardware configurations of these devices,there is an urgent need for efficient autonomous observation capabilities.An autonomous Master Control System(MCS)can ensure efficient performance,data consistency,and stability,and the prototype presented here adopts a microservices architecture,breaking down the hardware into multiple subsystems and converting their functions into individual services.A central decision-making system leads the operations,supported by three auxiliary systems and three device control systems.Through inter-subsystem service calls,it achieves rapid imaging and spectroscopic monitoring.To verify system stability and observation efficiency,the system was tested on the Solar Full-disk Multi-layer Magnetograph.Experimental results verify this system can operate automatically for 4 consecutive months,acquire photospheric vector magnetic and Doppler velocity fields within a 15-minute interval,and measure chromospheric longitudinal magnetic and Doppler velocity fields in under 180 s.This ensures consistent and stable solar monitoring and serves as a practical methodological benchmark for the development of similar devices.

Research on Teaching Reform of Landscape Engineering Course based on the Concept of CDIO

With the advancement of new engineering construction,it is urgent to explore the teaching reform of professional courses in the cultivation of landscape architecture professionals in combination with industry needs.In order to solve the problems existing in the current Landscape Engineering course,such as traditional teaching methods,insufficient student interest,lack of practical links,and the disconnection between teaching content and industry demand.This study discusses the teaching reform of the Landscape Engineering course based on the CDIO(Conceive-Design-Implement-Operate)concept,aiming at solving the problems mentioned.Through the integration of CDIO mode,the core competencies that students should have are defined,including environmental landscape design and planning,innovative thinking,project management,and so on.The research emphasizes project-driven learning,interdisciplinary knowledge integration,and practical skill training,and puts forward strategies such as teacher training and professional development support to ensure the implementation of the reform.The purpose of the reform was to improve students’professional ability and employment competitiveness,promote the improvement of education quality and the sustainable development of the industry,and exert a positive impact on landscape engineering education and industry progress.

乡村教育政策执行者能动参与乡村教育振兴的协同机制分析

随着经济发展和社会转型,乡村教育政策执行研究由关注政府行为的决策者作用转向强调执行者在政策执行中的适应性,再到关注执行者参与政策过程的复杂性与动态性。在乡村振兴背景下,基于四川省县域内乡村教育振兴的案例,发现乡村教育政策执行者作为有自身优势潜能的能动者,通过政府部门统筹学校教育、家庭教育、社会教育协调发展,加强乡村学校、家庭和社会的有机衔接与有效合作,形成乡村教育政策协同育人机制,激发乡村教育振兴政策宣传的积极性、多层次协商规划乡村教育振兴活动、乡村需求与乡村教育政策实施协调搭配、扩大乡村教育政策实施效力,使乡村教育振兴初步呈现出积极效果,进一步突破政策效果不理想的问题。展望未来,乡村教育政策执行者能动参与乡村振兴的研究应立足我国乡村教育改革与发展的实际,借鉴国外研究实践体系,更好地服务于巩固拓展脱贫攻坚成果同乡村振兴的有效衔接。

不同黏粒含量红黏土失水与开裂关联性分析

为了研究不同黏粒含量对红黏土裂隙性的影响,制备4种含水率的试样,分别观察试样在20℃和60℃2种温度条件下裂隙的发展规律,并使用Image J图像处理软件对裂隙面积、裂隙率、裂隙长度进行测量和计算,对失水过程与开裂过程进行关联性分析。结果表明:当含水率相同时,相同黏粒含量红黏土的裂隙面积和裂隙长度发育的起止失水率随温度的升高而增大;当失水温度相同时,相同黏粒含量红黏土裂隙面积和裂隙长度发育的起止失水率随初始含水率的增大先下降后上升;当温度和含水率相同时,红黏土的表面收缩率随黏粒含量的增加逐渐减小;黏粒含量的变化与试样裂隙面积、裂隙长度发育的起止失水率之间未呈现出明显关联。

基于三维数字地质的深基坑排桩支护渗流耦合稳定性数值分析

建筑深基坑支护工程中地下水渗流作用是影响支护稳定的重要因素,准确进行渗流应力耦合计算是解决深基坑排桩支护稳定性的关键。以某商业综合楼建筑深基坑为研究对象,设计双排桩加3排预应力锚索复合支护试验方案,筛选有效数字地质参数,利用PLAXIS有限元软件构建基于渗流应力耦合作用的有限元模型,研究在不同开挖深度与不同支护参数下深基坑支护稳定性。结果表明:在不同开挖深度下,深基坑支护水平位移受渗流应力、开挖深度影响较大,开挖深度越深,支护水平位移和承受弯矩越大,基坑稳定性也随之变差;在不同支护参数下,通过增加支护桩嵌固深度、增加支护桩桩径,可减小支护的水平位移与弯矩,提升支护的稳定性。综合考虑开挖深度与支护参数,采用渗流应力耦合有限元模型数值模拟结果表明,当支护桩嵌固深度为10m,桩径为1.1m,双排桩加3排预应力锚索复合支护结构稳定性最优,支护最大水平位移与最大弯矩,均满足上限值要求;当支护双排桩最大排距超过4.0m,前后排桩的连接性变差,支护整体性能及稳定性降低。

纤维素纳米晶的空间受限自组装:从胶体液晶到功能材料

作为最有前途的生物衍生材料之一,纤维素纳米晶体(CNCs)具有来源广泛、生物相容性好和可形成光子结构等优点,在能源、生物医学和光子材料领域具有重要的应用价值.本文总结了CNCs的制备、CNCs形成的胆甾型胶体液晶及CNCs衍生的光子材料的研究进展,重点评述了CNCs在液滴和毛细管中的自组装和基于CNCs空间受限组装的功能材料研究进展,并讨论了空间受限CNCs自组装研究面临的挑战和未来的发展方向.

碳交易制度下绿色供应链不同成本分担合同选择

研究由一个制造商和一个零售商组成的绿色供应链中,不同成本分担合同选择问题.在碳交易制度下构建零售商不分担制造商成本(记为NC)和分担制造商绿色技术研发成本(记为RC)、生产成本(记为MC)、碳交易成本(记为TC)四种博弈模型.结果表明,相对于NC情形,RC总能提高制造商碳减排水平和零售商订购数量,而另外两种博弈模型不改变这两个决策.RC总能提高制造商利润,但是只有当零售商成本分担固定比例较低时,RC才能提高零售商利润.MC不改变参与各方利润.TC会降低制造商利润,但会提高零售商利润.当零售商成本分担固定比例较低时,RC能同时实现最高制造商碳减排水平和最高参与各方利润.

Improved interfacial adhesion for stable flexible inverted perovskite solar cells

Flexible perovskite solar cells have attracted widespread attention due to their unique advantages in lightweight,high flexibility,and easy deformation,which are suitable for portable electronics.However,the inverted(p-i-n)structured devices suffer from poor stability largely due to the low adhesion at the brittle interface(the hole transport layer/perovskite).Herein,zeolitic imidazolate framework-67(ZIF-67)is applied to inverted structured cells to optimize the interface and prolong the device lifetime.As a result,the flexible devices based on ZIF-67 obtain the champion power conversion efficiency of 20.16%.Over 1000 h under continuous light irradiation,the device retains 96%and 80%of its original efficiency without and with bias,respectively.Notably,devices show mechanical endurance with over 78%efficiency retention after 10,000 cycles of consecutive bending cycles(R=6 mm).The introduction of ZIF-67 suppresses the cracking in device bending,which results in improved environmental stability and bending durability.

Measurements of Majorana transition frequency shift in caesium atomic fountain clocks

The caesium atomic fountain clock is a primary frequency standard.During its operation,a Majorana transition frequency shift will occur once a magnetic field at some special locations along the atomic trajectory is singular.In this study,by developing a physical model,we analyzed the magnetic field requirements for atomic adiabatic transition and calculated the influence of the Majorana atomic transition on the atomic state via a quantum method.Based on the simulation results for the magnetic field in the fountain clock,we applied the Monte Carlo method to simulate the relationship between the Majorana transition frequency shift and the magnetic field at the entrance of the magnetic shielding,as well as the initial atomic population.Measurement of the Majorana transition frequency shift was realized by state-selecting asymmetrically populated atoms.The relationship between the Majorana transition frequency shift and the axial magnetic field at the entrance of the magnetic shielding was obtained.The measured results were essentially consistent with the calculated results.Thus,the magnetic field at the entrance of the magnetic shielding was configured,and the Majorana transition frequency shift of the fountain clock was calculated to be 4.57×10^(-18).

Fabrication and Modification Strategies of Metal Halide Perovskite Absorbers

Due to the long carrier lifetime,high carrier mobility,and high absorption coefficient of perovskite materials,the power conversion efficiency(PCE)of perovskite solar cells(PSCs)has increased from 3.8%in 2009 to 25.7%in 2021,which have already surpassed the PCE of thin-film solar cells and closes to the efficiency of Si-based photovoltaics(26.7%).Therefore,PSCs have become a promising clean energy technology for commercialization.However,the low defect formation energy of perovskite leads to a higher defect density than other conventional photovoltaic materials.It results in severe non-radiative recombination,limiting its further development and the commercialization.In this review,we summarize the mechanism and strategies for high-quality perovskite absorber fabrications to minimize the bulk and surface/interface defects of halide perovskite,including film quality development and interface modification.Strategies are proposed for further promoting the film quality and the corresponding device performance.Finally,we highlight the challenges that need to be overcome to control over the defect properties of halide perovskite.

Dark matter is darker

New results for directly searching for dark matter electromagnetic interactions have been reported by the PandaX Collaboration.The study reveals the most stringent upper limits on dark matter charge radius,millicharge,magnetic dipole moment,electric dipole moment,and anapole moment to date.These findings demonstrate that dark matter is significantly darker than previously anticipated.