摘要：α-Diimide catalysts have attracted widespread attention due to their unique chain walking characteristics.A series ofα-diimide nickel/palladium catalysts with different electronic effects and steric hindrances were designed and synthesized for olefin *** this work,we synthesized a series of asymmetricα-diimide nickel complexes with different steric hindrances and used them for ethylene *** nickel catalysts have high ethylene polymerization activity,up to 6.51×10^(6)g·mol^(−1)·h^(−1),and the prepared polyethylene has a moderate melting point and high molecular weight(up to 38.2×10^(4)g·mol^(−1)),with a branching density distribution between 7 and 94 branches per 1000 *** importantly,the polyethylene prepared by these catalysts exhibits excellent tensile properties,with strain and stress reaching 800%and 30 MPa,respectively.

摘要：高活性MOF基催化剂的设计和合成为促进动力学不利的氧还原反应(ORR)过程开辟了新的途径.本研究通过在ZIF-8前驱体表面涂覆二茂铁甲酸,然后进行两步炭化工艺,设计和制备了一种具有新型结构的高效电催化剂,以提高ORR性能.两步炭化过程对于将热解Fe_(3)C纳米颗粒封装到碳纳米管(CNTs)中以及将Fe单原子隔离到N掺杂碳(NC)基体上至关重要.此外,Fe元素的相对含量对优化催化剂的ORR性能至关重要.所制得Fe_(3)C@CNTs/NC-M催化剂结构先进,在碱性溶液中表现出良好的长期稳定性和电催化ORR性能,其半波电位和极限电流分别达到0.941 V和6.31 mA cm^(-2).此外,该电催化剂在甲醇溶液中具有较强的耐受性和良好的稳定性.Fe_(3)C@CNTs/NC-M锌空气电池(ZAB)具有1.525 V的开路电位,420 mA cm^(-2)时的峰值功率密度为348 mW cm^(-2),10 mA cm^(-2)时的最大容量为843 mA h g_(Zn)^(-1).因此,这种合成策略为构建具有有效和稳定的ORR性能的MOF基电催化材料提供了一条有效途径.

摘要：Cadmium sulfide(CdS)is an n-type semiconductor with excellent electrical conductivity that is widely used as an electron transport material(ETM)in solar *** present,numerous methods for preparing CdS thin films have emerged,among which magnetron sputtering(MS)is one of the most commonly used vacuum *** this type of technique,the substrate temperature is one of the key deposition parameters that affects the interfacial properties between the target film and substrate,determining the specific growth habits of the ***,the effect of substrate temperature on the microstructure and electrical properties of magnetron-sputtered CdS(MS-CdS)films was studied and applied for the first time in hydrothermally deposited antimony selenosulfide(Sb_(2)(S,Se)_(3))solar *** the substrate temperature not only results in the design of the flat and dense film with enhanced crystallinity but also leads to the formation of an energy level arrangement with a Sb_(2)(S,Se)_(3)layer that is more favorable for electron *** addition,we developed an oxygen plasma treatment for CdS,reducing the parasitic absorption of the device and resulting in an increase in the short-circuit current density of the solar *** study demonstrates the feasibility of MS-CdS in the fabrication of hydrothermal Sb_(2)(S,Se)_(3)solar cells and provides interface optimization strategies to improve device performance.

摘要：电催化水分解产生绿色氢气是发展可持续能源体系的重要途径之一。由过渡金属Ni、Mo组成的具有高活性、低成本的非晶态合金被广泛认为是一种有效的制氢催化剂。重点关注以镍钼(NiMo)基非晶合金为代表的催化剂,总结非晶态合金的制备方法及其在催化领域的应用,分别叙述NiMo合金、NiMo基中熵合金和NiMo基高熵合金在电催化析氢反应(HER)中的应用。结果表明,在合理的功能导向设计下,通过对关键科学及技术问题的解决,NiMo基非晶态合金催化剂能够表现出良好的析氢性能,最后提出在制备技术、组分调控、纳米化、电子结构以及活化机理5个方面还有待解决的问题。这对于催化剂的设计、制备、构效关系及催化机理的研究具有一定的参考价值。

摘要：各向同性磁流变弹性体是一种将磁性颗粒随机掺入到聚合物基体中制备而成的智能材料。在磁场作用下,其模量发生快速、可逆、连续变化,在振动控制领域显示出良好的应用前景。实验结果表明,各向同性磁流变弹性体的动态力学行为具有很强的频率、应变幅值和磁场相关性。尽管上述行为对于其潜在应用具有重要的影响,但目前关于各向同性磁流变弹性体磁相关非线性动态力学行为的理论研究则关注不够。为准确评价各向同性磁流变弹性体的动态力磁耦合行为,并指导其相关产品的设计,本文建立了一个基于连续介质力学理论,反映各向同性磁流变弹性体磁相关非线性动态力学行为的本构模型。随后,开发了和本构模型对应的数值实现算法,并对模型的预测能力进行了验证。该模型有助于深入理解各向同性磁流变弹性体磁相关非线性动态力学行为的潜在力学机制。此外,该模型有助于指导基于各向同性磁流变弹性体产品的设计和应用。

摘要：将不同金属元素通过合金化形成二维材料(金属烯)对基础研究和纳米电子器件的实际应用具有重要意义,但目前鲜有金属烯材料是具有本征带隙的半导体.受离子晶体成键特征的启发,通过结构搜索、成键分析和高通量第一性原理计算,本文从2500多个双金属烯中筛选出一系列具有晶格动力学稳定和碱金属-金离子键的二维碱金属金化物双金属烯半导体.由于碱金属和金之间的大电负性差,其中32个碱金属金化物双金属烯是带隙范围为0.97~5.20 eV的半导体材料,而锂金双金属烯由于电负性差减小呈现出金属性.Bohn-Oppenheimer分子动力学模拟表明19个双金属烯在室温下结构稳定有利于实际应用.这项研究为设计双金属烯半导体提供了指导,并揭示了二维金属合金中成键行为和电子结构性质间的关联.

摘要：电催化二氧化碳还原反应(CO_(2)RR)能够利用可再生电能将CO_(2)转化为高附加值化学品和燃料,是一项有望缓解当下环境挑战的技术方案.本文总结了CO_(2)RR稳足性下降的根本原因,并探讨了解决这一问题的有效策略以及最新的研究进展.首先,在外加电位的作用下,催化剂会发生结构转变,且碳沉积或气体杂质引起的催化剂中毒都会降低CO_(2)RR的稳定性.其次,气体扩散层(GDL)附近发生水淹和盐沉淀会阻碍反应物/生成物的传输,三相界面会受到破坏.在长时间服役时,液压和电流的作用会导致GDL开裂.在电解质方面,碱性电解质会与CO_(2)中和,形成碳酸盐沉淀;而酸性介质腐蚀催化剂,并伴随严重的析氢副反应.另外,电解质中的金属离子杂质的优先还原进一步加剧了稳定性的衰减.深入理解CO_(2)RR中各类失活现象对设计稳定、高效的CO_(2)电催化系统具有指导意义.针对CO_(2)RR稳定性研究目前所面临的困境,本文最后展望了该领域未来的研究方向.

摘要：线性霍尔传感器被广泛用于测量磁场强度,但针对霍尔传感器动态响应特性的研究却很少。为此,设计并搭建了一种线性霍尔传感器的频率响应特性测试平台。该平台由可控恒流源、线圈、线性霍尔传感器、低噪声放大器和数据采集装置组成,通过构建系统传递函数并提出动态更新的传递函数的方法,实现了霍尔传感器动态响应特性的精确测量。利用该平台分别测试了NHE520F和P3A两款芯片的动态特性性能。结果显示,在2.5 kHz-2 MHz范围内,这两款霍尔传感器在幅频特性和相频特性方面的性能差异在测试平台上被充分显现,而且霍尔传感器的动态特性参数与静态特性参数并非必然一致,动态特性分布也不相同。此外,根据多种温湿度条件下测得的霍尔传感器幅频特性与相频特性,绘制了霍尔传感器的平均动态特性曲线和3个标准差包络曲线。基于该测试平台获得的实验数据对研究霍尔传感器动态响应特性具有重要意义。

摘要：层状无机材料的弱层间耦合和大面积表面为构建低导热性无机固体材料提供了基本框架.合成具有足够散射和非谐波性的稳定层状材料,从而降低热导率,仍是一项挑战.本文在层状无机FeOCl材料体系中,通过一步氧化还原反应成功获得了一种结构稳定的富含Fe^(2+)的层状材料,实现了表面和界面的同步改性,并实现了超低的热导率.具体而言,系统的X射线吸收精细结构(XAFS)分析和电子能量损失光谱(EELS)分析表明,碱金属原子的层间插层和表面缺陷的引入诱导了大量Fe^(2+)的存在,从而增强了其非谐波性和声子散射.此外,声子态密度(PDOS)分布也提供了确凿的证据,证明了散射概率的提高和声子模式整体的软化.所制得的层状无机材料Fe(III)_(1−n)Fe(II)_(n)O_(1−x)Cl[K^(+)]_(m)不仅结构稳定,而且在298 K时的热导率比原始FeOCl降低了近60%,低至0.29 W m^(−1) K^(−1),这在层状无机材料中是极低的.这项研究为低导热层状材料的设计提供了新的视角.

摘要：Lightweight and efficient carbon-based microwave absorbents are significant in addressing the increasing severity of electromagnetic *** this study,hierarchical NiO/Ni nanosheets with a tuneable phase and morphology supported on a carbon fiber substrate(CF@NiO/Ni)were fabricated using a hydrothermal approach and post-annealing *** the annealing temperature increases,more metallic Ni is formed,and an apparent porosity appears on the sheet *** from the advantages of a three-dimensional(3D)conducting network,hierarchical porous structure,reinforced dipole/interface polarization,multiple scattering,and good impedance matching,the CF@NiO/Ni-500 composite exhibits an excellent microwave absorption performance even at a filling rate of only 3wt%.Specifically,its minimal reflection loss is-43.92 dB,and the qualified bandwidth is up to 5.64 *** addition,the low radar cross-section area of the CF@NiO/Ni composite coating confirms its strong ability to suppress electromagnetic wave *** expect that this work could contribute to a deeper understanding of the phase and morphology evolution in enhancing microwave absorption.