Re-delocalization of localized d-electrons in VO_(2)(R)-VS_(4)hetero-structure enables high performance of rechargeable Mg-ion batteries

Rechargeable Mg-ion batteries(MIBs)have attracted much more attentions by virtue of the high capacity from the two electrons chemistry.However,the reversible Mg^(2+)diffusion in cathode materials is restricted by the strong interactions between the high-polarized bivalent Mg^(2+)ions and anionic lattice.Herein,we design and propose a hetero-structural VO_(2)(R)-VS_(4)cathode,in which the re-delocalized d-electrons can effectively shield the polarity of Mg^(2+)ions.Theoretically,the electrons should spontaneously transfer from VS_(4)to VO_(2)(R)through the interfaces of hetero-structure due to the lower work function value of VS_(4).Furthermore,the internal electrons transfer lead to the electronic injection into VO_(2)(R)from VS_(4)and the partially broken V-V dimers,indicating the presence of lone pair electrons and charge re-delocalization.Benefiting from the shield effect of re-delocalized electrons,and the weakened attraction between cations and O/S anions enables more S^(2-)-S_(2)^(2-)redox groups to participate the electrochemical reactions and compensate the double charge of Mg^(2+)ions.Accordingly,VO_(2)(R)-VS_(4)hetero-structure exhibits a high specific capacity of 554 mA h g^(-1)at 50 mA g^(-1).It is believed that the charge re-delocalization of cathode extremely boost the Mg^(2+)ions migration for the high-capacity of MIBs.

Inducing Fe 3d Electron Delocalization and Spin‑State Transition of FeN_(4) Species Boosts Oxygen Reduction Reaction for Wearable Zinc–Air Battery

Transition metal-nitrogen-carbon materials(M-N-Cs),particularly Fe-N-Cs,have been found to be electroactive for accelerating oxygen reduction reaction(ORR)kinetics.Although substantial efforts have been devoted to design Fe-N-Cs with increased active species content,surface area,and electronic conductivity,their performance is still far from satisfactory.Hitherto,there is limited research about regulation on the electronic spin states of Fe centers for Fe-N-Cs electrocatalysts to improve their catalytic performance.Here,we introduce Ti_(3)C_(2) MXene with sulfur terminals to regulate the electronic configuration of FeN_(4) species and dramatically enhance catalytic activity toward ORR.The MXene with sulfur terminals induce the spin-state transition of FeN_(4) species and Fe 3d electron delocalization with d band center upshift,enabling the Fe(II)ions to bind oxygen in the end-on adsorption mode favorable to initiate the reduction of oxygen and boosting oxygen-containing groups adsorption on FeN_(4) species and ORR kinetics.The resulting FeN_(4)-Ti_(3)C_(2)Sx exhibits comparable catalytic performance to those of commercial Pt-C.The developed wearable ZABs using FeN_(4)-Ti_(3)C_(2)Sx also exhibit fast kinetics and excellent stability.This study confirms that regulation of the electronic structure of active species via coupling with their support can be a major contributor to enhance their catalytic activity.

Enhanced charge separation by interchain hole delocalization in nonfullerene acceptor-based bulk heterojunction materials

Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was characterized previously.However,the driving force that leads to this reduction was not clearly understood.In this study,we focus on the decreased carrier recombination loss and its driving force in optimized nonfullerene acceptor-based PTB7-Th:IEICO-4F BHJ composites.We demonstrate that the optimized BHJ shows deactivation in the sub-nanosecond nongeminate carrier recombination process.The driving force for this deactivation was determined to be the improved interchain hole delocalization between the polymers.An enhanced interchain hole delocalization was observed using steady-state photoinduced absorption(PIA)spectroscopy.In particular,increased splitting between the polaron PIA bands was noted.Moreover,improved interchain hole delocalization was observed for other state-of-the-art BHJ materials,including D18:Y6 with optimized morphologies.

“鲶鱼效应”下检察去地方化改革的新思路

检察地方化是我国司法公正的一项顽疾。党的十八大以来,我国采取了一系列保障检察机关依法独立行使检察权的措施,但去地方化的省级以下人财物统管并没有完全落实,跨行政区划检察改革只是从两家试点扩展至全国试点,检察的“省级化”仍有待实现。铁路运输检察机关具有的“鲶鱼”特质使其能在检察去地方化中发挥更为积极的作用,而且其参与的跨行政区划检察改革本身具备法律基础和现实需求。不过,这项改革试点的新增管辖存在正当性疑问,诉讼体系限制了去地方化程度,现实中改革的顶层设计迟缓与基层动力不足并存,亟须解困。最高人民检察院应当借用铁路运输检察机关的“鲶鱼效应”,通过完善其管辖范围,并与地方检察机关在人财物上保持动态平衡,实现检察去地方化改革的有效推进。

多层金属复合材料的应变局部化延迟和抗断裂失稳机理

多层金属复合材料在航天航空、汽车、船舶、核能电力领域中起着非常重要的作用。相比于传统单一金属,多层金属复合材料具有超高的塑性变形能力和断裂韧性。综述了多层金属复合材料在塑性变形过程中的应变局域化延迟和抗断裂失稳的特征和机理,归纳出周期性颈缩、脱层断裂、隧道裂纹、弥散剪切带对抑制多层金属复合材料塑性失稳的作用机理,并阐明脱层断裂、裂纹分叉、隧道裂纹对多层金属复合材料的增韧机理,和对韧脆转变行为的作用规律,可为金属材料强韧化提供新的设计思路和技术支撑。

Electronic structure and ultraviolet spectra of p-C_(6)H_(4)-C_(20)

Geometry optimization of p-C_(6)H_(4)-connected cyclo[20]carbon(p-C_(6)H_(4)-C_(20))was carried out at M062X/6-311G(d,p)level,three kinds of bond orders(Mayer,Laplacian,and Wiberg),electron-hole distributions,localized orbital locators(LOL),and infrared(IR)spectrum were also performed at the same level.Based on TD-DFT M062X/6-311G(d,p)method,the first 20 excited states and ultraviolet(UV)spectra of p-C_(6)H_(4)-C_(20) were calculated.Calculation results of π-electron delocalization analyses prove thatπ-electron delocalization of p-C_(6)H_(4)-C_(20) is more likely to occur on shorter C-C bonds rather than longer C-C bonds,and inside/outside of the ring plane rather than above/below the ring plane.Two absorption peaks of p-C_(6)H_(4)-C_(20) locate at about 319 nm and 236 nm,respectively.

凯库勒烯芳香性及光诱导电荷转移物理机制研究

芳香性是芳香族化合物的重要化学性质之一,明确环状共轭体系的芳香性对了解体系的化学反应性能和稳定性至关重要。通过量子化学计算和波函数分析对凯库勒烯(Kekulene)的芳香性、单光子吸收(OPA)和双光子吸收(TPA)光谱及电子转移特性进行了详细的研究;通过多中心键级和AV1245指数对分子中不同苯环的芳香性进行了定量分析;通过电子定域化函数(ELF)、定域化轨道定位函数(LOL)、磁感生电流和等化学屏蔽表面(ICSS)等多种方法,对Kekulene的芳香性进行了研究;通过电荷差分密度(CDD)对OPA和TPA跃迁过程的电子转移进行了可视化分析。结果表明,1、2环的芳香性明显强于3、4环;ELF和LOL的π电子可以在1环两侧高度离域并形成回路;OPA光谱具有较高跃迁偶极矩的激发态,更易成为TPA过程中的中间态。研究结果可为不同体系的芳香性提供有效的理论方法和应用途径。

近红外荧光探针增强共轭DDAO衍生物荧光团的理论设计及结构、电子和光谱性质研究

为提升1,3-二氯-7-羟基-9,9-二甲基-2(9H)-吖啶酮(1,3-dichloro-7-hydroxy-9,9-dimethly-2(9H)-acridinone,DDAO)的荧光成像效果,从理论上设计了5种增强共轭DDAO衍生物,引入双氰基异佛尔酮,增强受体能力及DDAO衍生物的共轭程度。采用密度泛函理论(density functional theory,DFT)探讨了强共轭DDAO衍生物的荧光响应机制和特性,并分析DDAO及其衍生物优化后的结构变化、激发和发射过程中的电子转移及跃迁性质等。结果表明,DDAO衍生物的供体-π-受体(donor-π-acceptor,D-π-A)结构存在增强的分子内电荷转移(intramolecular charge transfer,ICT)效应,导致荧光发射波长最大移至1295.01 nm。该研究证实了引入取代基能产生强共轭,使激发前后产生较大的斯托克斯(Stokes)位移。

三维碳球的物理性质研究

利用密度泛函理论(DFT)和波函数分析方法,从理论上探讨了三维碳球的光学性质。研究了紫外-可见光(Ultraviolet-visible, UV-vis)吸收光谱中的电子跃迁机制;通过跃迁密度矩阵图(Transition Density Matrix,TDM)和电荷差分密度图(Charge Density Difference, CDD),研究了三维碳球的电子激发特性;对拉曼(Raman)光谱进行了计算,并进一步解释了三维碳球的振动模式;利用静电势(Electrostatic Potential,ESP),研究了三维碳球与外界环境的相互作用;基于外加磁场下的磁感应电流,研究了三维碳球的电子离域程度。结果表明,三维碳球的吸收光谱主要在紫外光区域,并且有较强的电子离域能力。研究结果可为其他三维π共轭分子结构在线性光学和非线性光学中的应用提供理论基础。

基于建构主义的高校教学展示空间研究

文章重新定义高校校园公共空间和非正式学习空间,将其转化为教学展示空间。以建构主义学习方式为依托,把以往常规的独立的教学展示呈现到校园生活中的方方面面,融入学生的学习和生活过程中,将教学展示和学习行为高度结合。通过展示性学习环境提供可支持的空间从而促进学生学习,深入研究主动学习和高阶学习所需的空间,形成具有探究性的学习场所,呈现校园教学研究深度展示空间,进而提升文化品牌形象。

Localization and delocalization of a one-dimensional system coupled with the environment

We investigate several models of a one-dimensional chain coupling with surrounding atoms to elucidate disorder- induced delocalization in quantum wires, a peculiar behaviour against common wisdom. We show that the localization length is enhanced by disorder of side sites in the case of strong disorder, but in the case of weak disorder there is a plateau in this dependence. The above behaviour is the conjunct influence of the coupling to the surrounding atoms and the antiresonant effect. We also discuss different effects and their physical origin of different types of disorder in such systems. The numerical results show that coupling with the surrounding atoms can induce either the localization or delocalization effect depending on the values of parameters.

Intraparticle Charge Delocalization through Conjugated Metal-Ligand Interfacial Bonds:Effects of Metal d Electrons

Intraparticle charge delocalization occurs when metal nanoparticles are functionalized with organic capping ligands through conjugated rnetal-ligand interfacial bonds. In this study, metal nanoparticles of 5d metals （Ir, Pt, and Au） and 4d metals （Ru, Rh, and Pd） were prepared and capped with ethynylphenylacetylene and the impacts of the number of metal d electrons on the nanoparticle optoelectronic properties were examined. Both FTIR and photoluminescence measurements indicate that intraparticle charge delocalization was en- hanced with the increase of the number of d electrons in the same period with palladium being an exception.

Electron delocalization enhances the thermoelectric performance of misfit layer compound(Sn_(1-x)Bi_(x)S)_(1.2)(TiS_(2))_(2)

The misfit layer compound(SnS)_(1.2)(TiS_(2))_(2)is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure.However,the strong covalent bonds within each constituent layer highly localize the electrons thereby it is highly challenging to optimize the power factor by doping or alloying.Here,we show that Bi doping at the Sn site markedly breaks the covalent bonds networks and highly delocalizes the electrons.This results in a high charge carrier concentration and enhanced power factor throughout the whole temperature range.It is highly remarkable that Bi doping also significantly reduces the thermal conductivity by suppressing the heat conduction carried by phonons,indicating that it independently modulates phonon and charge transport properties.These effects collectively give rise to a maximum ZT of 0.3 at 720 K.In addition,we apply the single Kane band model and the Debye–Callaway model to clarify the electron and phonon transport mechanisms in the misfit layer compound(SnS)_(1.2)(TiS_(2))_(2).

THE SPIN DELOCALIZATION SUBSTITUENT PARAMETER σ 10. SYNTHESIS OF SUBSTITUTED α, β, β-TRIFLUOROSTYRENES BY THE Pd-CATALYZED CROSS-COUPLING OF TRIFLUOROVINYLZINC BROMIDE WITH ARYL HALIDES

Palladium-catalyzed coupling of trifluorovinylzinc reagent with substituted aryl halides Y-C_6H_4-X (Y=p-NO_2, p-and m-COOMe, p-COOH, p-CONH_2, p- and m-CN; X=Br, I, Cl) provides a synthetic method for α, β, β-trifluorostyrenes(Y-TFS's). A series of previously unavailable Y-TFS's were thus obtained.

Entanglement-Enhanced Two-Photon Delocalization in a Coupled-Cavity Array

We study the transport properties of two entangled photons which are initially injected into two nearest-neighbor coupling cavities in an one-dimensional coupled-cavity array （CCA）. It is found that photonic transport dynamics in the two-photon CCA exhibits the entanglement-enhanced two-photon delocalization phenomenon. It is shown that the CCA can realize the localization-to-delocalization transition for two entangled photons.

跨越城乡的媒介空间:城乡融合的媒介社会学研究

基于嵌入-连接视角,探究了作为“中介景观”的媒介空间将城市性和乡村性纳入流动化网络情景之中的过程机制:脱域与再嵌入。借助流动性媒介空间中的交往实践,城乡居民在异质性的生活观念、情感价值、身份认同和地理感知等维度建立起对彼此的想象与认知。媒介空间对距离、认同、价值等不可见价值的描述和阐释,意味着现实语境下作为一种生产力量的城乡多元主体已经全面参与到城乡关系重构、要素聚合与空间关系的“流动化生产”之中。作为承载情景建构和关系再生产的“第三场域”,媒介空间也将为乡土公共性的重建和乡村振兴提供新的现代性路径。

元宇宙赋能政府数字治理的三维释读:逻辑理路、总体方略与关键问题

元宇宙的形成标志着社会数字化发展进入高级阶段,也势必会引致对当前政府数字治理体系的进一步创制。技术叙事中有关未来治理的想象,以及现实中基于商业资本运作下的“游戏”超域效应揭示了元宇宙赋能政府数字治理的可能性以及前景。以顶层设计与底层创新的上下衔接为基础,提出了以“原理-模式-载体-效能”为线索的逻辑理路。其中,元宇宙支撑构建的数字技术—经济混合规律体系作为治理原理为政府数字治理创新提供了原动力,而发展出的新型数字情境治理模式以“置换”和“仿拟”逻辑赋予了主体“在场”能力,并构建“自由人联合体空间”作为载体强化数字治理中人的主体性地位,最终实现以秩序正义为核心的治理效能。从当前政府数字治理的现实困境出发,构筑元宇宙赋能政府数字治理的总体方略:包括锚定真实治理需求、优化政府组织结构以及耦合数字平台建设3条赋能路径,并形成以重点项目牵引、多元主体联动、多样智能治理连接、复杂智慧体系融入为特征的行动策略。未来,元宇宙赋能政府数字治理的关键还在于重视“脱域”视界下政府数字治理制度的逻辑转换,强化“游戏”情境下政务平台公共性的保障,以及警惕“超真实”符号世界的内生风险等问题。在此基础上,反思并追问元宇宙如何在可预见的未来延续和复兴技术治理的辉煌。

1-茚满基A^(2)A′′-X^(2)A′′电子跃迁0_(0)^(0)谱带的高分辨光谱

本文利用激光诱导荧光技术在473 nm波段研究1-茚满基A^(2)A′′-X^(2)A′′电子跃迁0_(0)^(0)谱带的高分辨转动光谱,实验光谱分辨率为0.014 cm^(-1).通过对实验光谱的转动分析,获得了基态A^(2)A′′和激发态X^(2)A′′的光谱常数,并检验了理论计算的1-茚满基平衡构型的准确性.结合理论计算分析了1-茚满基的分子轨道和自旋密度分布,揭示了1-茚满基中未成对p_(π)电子的离域特性及其和自由基稳定能之间的关联.

电子定域策略在实现平面四配位结构中的适用性:氮与碳的对比研究

本文通过对含有平面四配位氮团簇NLi_(3)E^(+)(E=N,P,As)和它们的平面四配位碳等电子体CLi_(3)E(E=N,P,As)进行详细地对比,研究了电子定域策略在设计含平面四配位氮团簇时的适应性.结果表明,NLi_(3)E^(+)团簇具有类似于CLi_(3)E的平面结构,且其平面性都是由一个定域的π键决定的.然而,与CLi_(3)E相比,NLi_(3)E^(+)明显具有更高的电子结构稳定性、热力学稳定性和动力学稳定性,这可以从更宽的HOMO-LUMO能隙(4.58~4.68 eV vs.2.10~2.74 eV)在CCSD(T)/aug-cc-pVTZ水平下较低的能量和DFT水平下的分子动力学模拟中表现出的更好刚性得到验证.结果表明,电子定域策略可能更适合设计中心原子为较高电负性且更倾向于形成定域键的平面多配位分子.在这些团簇中,NLi_(3)E^(+)的稳定性最好,更适合进行气相合成及后续的质谱选择和光谱表征.

脱域与重塑:传统武术传承场域的变迁研究

运用文献资料法,对我国传统武术传承场域的脱域现象和作用机制进行分析,研究认为,重塑传统武术传承场域具有文化、教育、经济等方面价值。并提出了建构传统武术文化符号,回归武术本源;创新传承场域内容理念,打造威望域区;构建三位一体传承场域,鼓励民众参与等重塑传统武术传承场域的路径选择,旨在为我国传统武术传承场域重塑提出可行性建议。