摘要：磁场触发的催化剂轨道电子自旋排列已成为促进析氧反应的一种有趣而可行的策略.然而,具有强d-d库仑相互作用的高熵合金(HEAs)催化剂中的磁场增强机制尚未得到充分挖掘.在此,我们设计了具有优异软磁性的高熵合金金属片,在微小磁场下表现出显著的磁场增强催化作用,其磁导率可作为评估磁场增强的描述因子.具体地,仅施加50 mT的磁场,(FeCoNi)_(82.5)Cr_(17.5)HEAs的过电位下降就超过了36mV@10 mA cm^(-2).此外,过电位的降低与HEA的磁导率呈线性关系.原位拉曼光谱与理论计算结果表明,施加磁场可显著提高自旋密度,改善催化剂的3d电子与*O自由基的2p轨道之间的自旋相互作用,从而有效降低速率决定步骤(*O→*OOH)的能量障碍,进而促进O-O的形成.

摘要：氢键有机框架材料(HOFs)在催化领域具有巨大的潜力,但其孔道空间在去除溶剂后易塌陷,限制了其在光催化能源转换和存储方面的应用.本研究采用孔道分割策略成功设计并合成了一种稳定孔道结构、高效光催化CO_(2)还原活性的HOF催化剂.H4TBAPy分子通过与HOF孔道中大量的CH…π相互作用锚定自身,并将HOF的大孔道分隔成多个小空间,显著增加了HOF框架的稳定性.同时,富电子属性的H4TBAPy分子提升了HOF体系中电子的传输速率,从而提高了催化活性.这项研究为设计稳定、高性能的HOFs光催化剂提供了新策略.

摘要：单价Ag+或Li+引入到类金刚石结构的MQ22-(M=Ga,In;Q=S,Se)阴离子基团中能合成出良好的二阶非线性光学(NLO)晶体材料.然而,这些晶体分别面临着较低的抗激光损伤阈值(LIDT)或二氧化硅易被腐蚀等缺点,严重限制了其在高功率激光应用中的实用性.在本研究中,基于类金刚石结构的ZnSe,我们采用[Se_(4)Zn_(13)]Se_(2)4→[ClRb_(3)Ba]Se_(24)非常规的聚阳离子取代策略,设计并合成了一种新型的盐包硫属化合物[Rb_(3)BaCl][In_(8)Se_(14)](1).化合物1属于压缩黄铜矿型硒化物并保持了与AgInSe_(2)相同的晶体对称性(I-42d空间群).值得注意的是,由于InSe_(4)四面体结构单元的平行排列,化合物1具有相位匹配的强二次谐波(SHG)响应(2.0倍于AgGaS_(2)@2.90μm).此外,聚阳离子[Rb_(3)BaCl]^(4+)的引入促进了光学带隙(2.02 eV)的增强,有效地避免了对2.09μm激光的双光子吸收;同时结合较低的热膨胀系数,使得化合物1表现出高的LIDT(3.2倍于AgGaS2@2.09μm).本研究验证了在类金刚石结构中进行聚阳离子取代的可行性,并成功获得了性能优异的中远红外NLO材料.

摘要：The H_(∞)control method is an effective approach for attenuating the effect of disturbances on practical systems, but it is difficult to obtain the H_(∞)controller due to the nonlinear Hamilton-Jacobi-Isaacs equation, even for linear systems. This study deals with the design of an H_(∞)controller for linear discrete-time systems. To solve the related game algebraic Riccati equation(GARE), a novel model-free minimax Q-learning method is developed, on the basis of an offline policy iteration algorithm, which is shown to be Newton’s method for solving the GARE. The proposed minimax Q-learning method, which employs off-policy reinforcement learning, learns the optimal control policies for the controller and the disturbance online, using only the state samples generated by the implemented behavior policies. Different from existing Q-learning methods, a novel gradient-based policy improvement scheme is proposed. We prove that the minimax Q-learning method converges to the saddle solution under initially admissible control policies and an appropriate positive learning rate, provided that certain persistence of excitation(PE)conditions are satisfied. In addition, the PE conditions can be easily met by choosing appropriate behavior policies containing certain excitation noises, without causing any excitation noise bias. In the simulation study, we apply the proposed minimax Q-learning method to design an H_(∞)load-frequency controller for an electrical power system generator that suffers from load disturbance, and the simulation results indicate that the obtained H_(∞)load-frequency controller has good disturbance rejection performance.

摘要：一条稳定的基于 Lyapunov 的控制法律在这份报纸为纠纷状态准备被建议。一个二纺纱的系统的数学模型在相互作用图画被构造。看得见的操作员的平均的值作为 Lyapunov 函数被选择。这份报纸设计看得见的操作员保证目标状态在 Lyapunov 感觉是稳定的。然后，作者分析控制系统的集中，并且证明钟状态在设计的控制法律下面是 asymptotically 稳定的。与另外的方法相比，控制方法在这建议纸有容易的设计和集中的优点到目标状态。为贝尔状态的准备的数字模拟实验被实现。

摘要：Cobalt nanoparticles(NPs)catalysts are extensively used in heterogeneous catalytic reactions,and the addition of alkali metal promoters is a common method to modulate the catalytic performance because the catalyst's surface structures and morphologies are sensitive to the addition of ***,the underlying modulation trend remains ***,the adsorption of alkali metal promoters(Na and K)on the surfaces of face-centered-cubic(FCC)and hexagonal-closest packed(HCP)polymorphous cobalt was systematically investigated using density functional ***,the effect of alkali promoters on surface energies and nanoparticle morphologies was revealed on the basis of Wulff *** FCC-Co,the exposed area of the(111)facet in the nanoparticle increases with the adsorption coverage of alkali metal ***,the(311),(110),and(100)facets would disappear under the higher adsorption coverage of alkali *** HCPCo,the Wulff morphology is dominated by the(0001)and(1011)facets and is independent of the alkali metal adsorption *** work provides insights into morphology modulation by alkali metal promoters for the rational design and synthesis of cobalt-based nanomaterials with desired facets and morphologies.

摘要：全球首颗可持续发展科学卫星—SDGSAT-1于2021年11月5日成功发射,由可持续发展大数据国际研究中心(SDG中心)研制并运行.为满足全球可持续发展目标(SDGs)监测、评估和研究的需要,SDGSAT-1通过热红外、微光和多谱段三个载荷的全天时协同观测,旨在实现“人类活动痕迹”的精细刻画,为表征人类活动与自然环境交互作用的SDG指标研究提供支撑,服务全球SDGs的实现.SDGSAT-1拥有全球首创彩色微光设计,10 m全色和40 m彩色微光分辨率;可以30 m分辨率探测地表0.2℃的温度变化;2个深蓝波段和1个红边波段设计,可准确探测不同水体水质变化及植被生长情况.2022年9月启动了“SDGSAT-1开放科学计划”,实现卫星数据全球开放共享,为2030年议程和全球发展倡议实施提供科技支持.

摘要：Recent emergence of diverse services have led to explosive traffic growth in cellular data networks. Understanding the service dynamics in large cellular networks is important for network design, trouble shooting, quality of service(Qo E) support, and resource allocation. In this paper, we present our study to reveal the distributions and temporal patterns of different services in cellular data network from two different perspectives, namely service request times and service duration. Our study is based on big traffic data, which is parsed to readable records by our Hadoop-based packet parsing platform, captured over a week-long period from a tier-1 mobile operator's network in China. We propose a Zipf's ranked model to characterize the distributions of traffic volume, packet, request times and duration of cellular services. Two-stage method(Self-Organizing Map combined with kmeans) is first used to cluster time series of service into four request patterns and three duration patterns. These seven patterns are combined together to better understand the fine-grained temporal patterns of service in cellular network. Results of our distribution models and temporal patterns present cellular network operators with a better understanding of the request and duration characteristics of service, which of great importance in network design, service generation and resource allocation.

摘要：二维Ruddlesden-Popper型杂化钙钛矿(A′)_(2)(A)_(n-1)M_(n)X_(3n+1)表现出独特的物理特性与结构兼容性,已经发展成为光电材料的强有力候选者,其无机组分与有机组分的准确调控为优化材料性能提供了广阔空间.到目前为止,将大尺寸有机基元作为A位离子占据钙钛矿空腔仍是一项挑战,形成此类结构的二维多层钙钛矿材料非常稀少.鉴于此,我们将仲胺和芳香胺作为混合阳离子,利用复合阳离子自组装方法成功制备了结构新颖的Ruddlesden-Popper型钙钛矿(4-TFBMA)_(2)(DMA)Pb_(2)I_(7),其中4-TFBMA为4-(三氟甲基)苄胺,DMA为二甲胺.该化合物具有典型的双层钙钛矿结构,DMA作为A位阳离子处于骨架空腔内,突破容忍因子制约;无机骨架层与间隔阳离子4-TFBMA层交替排列产生量子阱.以高质量晶体为基础组装的阵列探测器表现出优异的面内光电性能,如探测率高、响应度大、暗电流低和响应速率快等,性能参数可以媲美二维无机材料.综上,该工作为设计合成新颖二维钙钛矿化合物及实现高效光电探测性能提供了重要参考.

摘要：We present a novel and simple design of an air-slot mode-gap photonic crystal(PC) nanocavity by introducing a linear air slot to the center of a line-defect waveguide in a two dimensional triangular-lattice silicon PC slab.A high quality factor(Q factor) of 8.42*105 and an ultrasmall mode volume of 0.998 cubic wavelength are achieved in an optimized air-slot nanocavity which is a suitable choice for the strong matter-field interaction in free *** high Q cavities with ultrasmall mode volume are important for applications such as quantum computation and nonlinear optics.