摘要：The subthalamic nucleus(STN)is considered the best target for deep brain stimulation treatments of Parkinson’s disease(PD).It is difficult to localize the STN due to its small size and deep *** microelectrode arrays(MEAs)can rapidly and precisely locate the STN,which is important for precise *** this paper,16-channel MEAs modified with multiwalled carbon nanotube/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(MWCNT/PEDOT:PSS)nanocomposites were designed and fabricated,and the accurate and rapid identification of the STN in PD rats was performed using detection sites distributed at different brain *** results showed that nuclei in 6-hydroxydopamine hydrobromide(6-OHDA)-lesioned brains discharged more intensely than those in unlesioned *** addition,the MEA simultaneously acquired neural signals from both the STN and the upper or lower boundary nuclei of the ***,higher values of spike firing rate,spike amplitude,local field potential(LFP)power,and beta oscillations were detected in the STN of the 6-OHDA-lesioned brain,and may therefore be biomarkers of STN *** with the STNs of unlesioned brains,the power spectral density of spikes and LFPs synchronously decreased in the delta band and increased in the beta band of 6-OHDA-lesioned *** may be a cause of sleep and motor disorders associated with ***,this work describes a new cellular-level localization and detection method and provides a tool for future studies of deep brain nuclei.

摘要：以著名的LiB_(3)O_(5)为模板,通过增强其结构中B_(2)O_(5)的夹角使双折射更小,在封闭体系中通过高温溶液法获得了两种新的用于制造零级波片的双折射晶体Li_(2)MLaB_(18)O_(30)(M=Rb,Cs).有趣的是,相邻的B_(2)O_(5)接近垂直排列,使得它们表现出比商用石英晶体(Δn~0.0092在可见光区域)小得多的双折射率(分别为0.0032@532 nm和0.0027@532 nm).此外,Li_(2)MLaB_(18)O_(30)(M=Rb,Cs)晶体的紫外截止边均低于200 nm,表明它们可用作深紫外区域的零级波片材料.

摘要：过渡金属氧化物具有丰富的功能性,但其错综复杂的内部自由度对相图绘制和结构设计提出了挑战.本文中,我们引入了描述相图物理起源的轨道能级序(ELO),并通过对La_(0.67)Sr_(0.33)MnO_(3)(LSMO)氧化物的研究证明了其在相图预测中的有效性.结合DFT计算和实验,我们构建了氧含量和应变关联的LSMO相图,结果表明LSMO结构稳定性与ELO密切相关.据此发现了一种由ELO演化而产生的四倍氧有序相.最后,我们提出了描述轨道分裂程度的轨道弹性定律,阐明了ELO演化的起源,助力功能氧化物的设计.这项研究拓宽了材料科学领域的性能调控手段,并为从轨道角度预测相图提供了思路.

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：流感病毒和新型冠状病毒(SARS-CoV-2)是近年来频繁引发呼吸道疾病的主要病原,其引起的黏膜免疫应答对于病毒的控制和清除至关重要.目前对于SARS-CoV-2感染后肺部黏膜免疫应答的具体调控机制及其与流感感染的区别尚不清楚我们通过原位杂交-多重免疫荧光染色技术及空间转录组学揭示了流感病毒和SARS-CoV-2感染过程中局部免疫应答的动态变化过程,并发现相比于流感病毒感染,SARS-CoV-2感染早期肺部黏膜会更加快速地形成诱导性支气管相关淋巴组织(iBALT)结构并活化B1细胞产生较高水平IgM和IgA,可能在抗病毒感染及iBALT的形成中发挥重要作用.同时,SARS-CoV-2及表达其S蛋白的假病毒感染均能够促进小鼠和人的B1细胞的活化.将表达S蛋白的腺病毒疫苗AdC7-S对小鼠进行免疫后,可以成功诱导出包含B1细胞的iBALT,并在病毒感染中发挥保护作用.本研究揭示了呼吸道病毒引起的肺脏黏膜免疫动态应答过程,并阐明了SARS-CoV-2感染早期B1细胞的活化特点及免疫保护作用,为揭示新发呼吸道传染病的保护性应答机制及疫苗设计提供了理论基础.

摘要：Since LiOsO_3 was discovered, obtaining easy-accessible polar metals for research and applications has been challenging. In this paper, we present a multilayer design strategy, which is configured as ferroelectric layer/carrier reservoir layer/isolation layer/substrate, for obtaining polar metals by electrostatically doping a strained ferroelectric material in a more effective way. In the proposed configuration, both 1 unit-cell thick BaTiO_3 and PbTiO_3 exhibited considerable Ti off-centering with various strains,which should extend the applicability of ferroelectric-based polar metals in ultra-thin devices. Moreover, engineered by the compressive strain and the BaTiO_3 thickness, the design strategy effectively achieved polar metallicity and dimensionalitytunable electronic states associated with the modulation of highly anisotropic properties such as electrical and electronic thermal conductivity, which may be helpful for designing ultra-thin, ultrafast, and low-power switch devices.

摘要：二氧化锡(SnO_(2))具有高的理论比容量,有望作为下一代锂离子电池负极材料.然而,Sn向SnO_(2)的不可逆转化以及充放电过程中巨大的体积变化限制了其实际的应用.本文基于三维互连多孔氧化铝模板,设计合成了一种由内腔同时填充NiO和SnO_(2)纳米颗粒的碳管基元相互连接组成的三维碳管网格膜,可以直接作为自支撑的高性能锂离子电池负极.该复合框架利用了NiO和SnO_(2)纳米颗粒的协同作用,不仅能够促进Sn向SnO_(2)的可逆转变,提高首次库伦效率,而且还可以缓释充放电过程中SnO_(2)剧烈的体积变化.此外,相互连接的三维碳管框架可以负载大量NiO和SnO_(2)纳米颗粒,缩短Li+的扩散距离,并作为快速的电子传输通道.因此,这种独特的结构赋予了该电极超高的储锂容量和倍率性能在1 A g^(-1)循环200次后,比容量达到928.5 mA h g^(-1),并且在4 A g^(-1)的高电流密度下仍然具有633.5 mA h g^(-1)的比容量.总之,这种独特的一体化结构在锂离子电池等储能领域具有广阔的应用前景.

摘要：探索具有深紫外相位匹配能力的新型非线性光学材料是当前研究热点.本文从硼氧阴离子框架出发,发现由π共轭BO_(3)基团组成一维(BO_(2))∞链的电子离域导致了极化特性增强,可实现非线性光学性能的优化.据此,本文预测了以(BO_(2))∞链为阴离子框架的CaBO_(2)F体系.重点研究了三种能量最低的结构CaBO_(2)F-Ⅰ,CaBO_(2)F-Ⅱ和CaBO_(2)F-Ⅲ,设计了热力学上可进行的反应路径.第一原理计算表明,CaBO_(2)F-Ⅰ,CaBO_(2)-F-Ⅱ和CaBO_(2)F-Ⅲ具有较宽的带隙,合适的双折射(0.076–0.108@1064 nm)和较大的倍频系数(2.1–2.7×KDP).其中,计算得到CaBO_(2)F-Ⅰ的最短相位匹配波长在约为195 nm(基于HSE06带隙修正剪刀算符),证明了含有定向电子离域的(BO_(2))∞链是深紫外非线性光学材料的潜在阴离子框架.本文通过将机理研究与验证性的结构预测相结合实现了自上而下设计深紫外非线性光学结构模板,该研究为探索新型非线性光学材料提供了新的策略.

摘要：The formations of desiccation cracks and their patterns in drying droplets of protein solutions are studied experimentally. The solvent evaporation causes the dehydration self-organization phenomenon in colloidal droplets, followed by the formations of desiccation cracks. Two categories of highly ordered crack patterns, which we name "daisy" and "wavy-ring", are identified in the drying droplets. We explore the shifting of crack patterns from the "daisy" to the "wavy-ring" by varying the concentration of protein droplets. The results show that the concentration correlates with the pattern of deposition film directly, and modulates the periodicity of the crack pattern. We investigate the formations and periodicities of these two kinds of crack patterns, and obtain the scaling law of periodicity of the "wavy-ring" crack pattern. The relationship between the deposition pattern and the highly ordered crack patterns is also examined. This study will help in understanding the formation mechanisms of crack patterns in drying droplets of protein solutions and assist the future design of crack patterns in practical applications.

摘要：3 m多长的伸杆机构是天问一号火星磁强计的一个重要组成部分,用于将磁通门磁强计探头伸离卫星本体以减小卫星对磁场测量的影响。火星磁强计伸杆机构是一种多关节、铰链转轴驱动的一次性展开机构。在设计时充分考虑到了其功能性、可靠性和系统约束要求等因素。力学分析和地面验证试验表明火星磁强计伸杆机构足以承受最坏情况下的在轨环境。在经历了漫长的地火转移旅程后,火星磁强计伸杆机构于2021年5月25日成功展开。展开过程耗时约4.6 s,两个探头被送至远离环绕器本体位置,其中外侧探头距离环绕器3.19 m,内侧探头距离环绕器2.29 m。展开到位后,外侧探头处所测得的磁场大小由1250 nT减弱至不到6 nT。火星磁强计伸杆机构为后续探测任务中需在低温环境下长期贮存的空间展开机构的研制提供了宝贵的工程经验。