使用四乙基氢氧化铵作为有机模板剂和常规硅铝源直接合成SSZ-13沸石分子筛

使用四乙基氢氧化铵作为有机模板剂,利用常规铝源和硅源而不需要高硅Y沸石作为起始原料,同时加入适量的沸石晶种直接合成了SSZ-13沸石分子筛.所合成的沸石产物结晶度好,具有良好的水热稳定性,并在氨选择性催化还原(NH₃-SCR)反应中显示出优异的催化性能,为其在工业上广泛应用提供了可能.     

O-GlcNAcylation mapping of single living cells by in situ quantitative SERS imaging

O-GlcNAcylation is involved in many biological processes including cancerization. Nevertheless, its in situ quantification in single living cells is still a bottleneck. Here we develop a quantitative SERS imaging strategy for mapping the O-GlcNAcylation distribution of single living cells. O-GlcNAcylated compounds (OGCs) can be quantified through their in situ azide labeling and then a click reaction competing with azide and Raman reporter labeled 15 nm-gold nanoparticles (AuNPs) for linking to dibenzocyclooctyne labeled 40 nm-AuNPs to produce OGC-negatively correlated SERS signals. The calibration curve obtained in vitro can be conveniently used for detecting OGCs in different areas of single living cells due to the negligible effect of cell medium on the click linkage and Raman signal. This method has been successfully applied in mapping O-GlcNAcylation distribution in different cell lines and monitoring O-GlcNAcylation variation during cell cycling, which demonstrate its great practicability and expansibility in glycosylation related analysis.

A quantitative SERS imaging strategy is developed for O-GlcNAcylation mapping of single living cells through a competitive click reaction.     

Bioimaging agents based on redox-active transition metal complexes

Detecting the fluctuation and distribution of various bioactive species in biological systems is of great importance in determining diseases at their early stages. Metal complex-based probes have attracted considerable attention in bioimaging applications owing to their unique advantages, such as high luminescence, good photostability, large Stokes shifts, low toxicity, and good biocompatibility. In this review, we summarized the development of redox-active transition metal complex-based probes in recent five years with the metal ions of iron, manganese, and copper, which play essential roles in life and can avoid the introduction of exogenous metals into biological systems. The designing principles that afford these complexes with optical or magnetic resonance (MR) imaging properties are elucidated. The applications of the complexes for bioimaging applications of different bioactive species are demonstrated. The current challenges and potential future directions of these probes for applications in biological systems are also discussed.

This review summarizes transition metal complexes as bioimaging agents in optical and magnetic resonance imaging.     

Fixed-Time Leader-Following Consensus Tracking Control for Nonliear Multi-Agent Systems under Jointly Connected Graph

This paper researches the fixed-time leader-following consensus problem for nonlinear multi-agent systems (MASs) affected by unknown disturbances under the jointly connected graph. In order to achieve control goal, this paper designs a fixed-time consensus protocol, which can offset the unknown disturbances and the nonlinear item under the jointly connected graph, simultaneously. In this paper, the states of multiple followers can converge to the state of the leader within a fixed time regardless of the initial conditions rather than just converging to a small neighborhood near the leader state. Finally, a simulation example is given to illustrate the theoretical result.     

Subcomponent self-assembly of circular helical Dy6(L)6 and bipyramid Dy12(L)8 architectures directed via second-order template effects

In situ metal-templated (hydrazone) condensation also called subcomponent self-assembly of 4,6-dihydrazino-pyrimidine, o-vanillin and dysprosium ions resulted in the formation of discrete hexa- or dodecanuclear metallosupramolecular Dy₆(L)₆ or Dy₁₂(L)₈ aggregates resulting from second-order template effects of the base and the lanthanide counterions used in these processes. XRD analysis revealed unique circular helical or tetragonal bipyramid architectures in which the bis(hydrazone) ligand L adopts different conformations and shows remarkable differences in its mode of metal coordination. While a molecule of trimethylamine acts as a secondary template that fills the void of the Dy₆(L)₆ assembly, sodium ions take on this role for the formation of heterobimetallic Dy₁₂(L)₈ by occupying vacant coordination sites, thus demonstrating that these processes can be steered in different directions upon subtle changes of reaction conditions. Furthermore, Dy₆(L)₆ shows an interesting spin-relaxation energy barrier of 435 K, which is amongst the largest values within multinuclear lanthanide single-molecular magnets.

Subcomponent self-assembly gave access to Dy₁₂(L)₈ and Dy₆(L)₆ architectures via second-order template effects. The Dy₆(L)₆ assembly behaves as a single-molecule magnet exhibiting a high anisotropy barrier and butterfly-shaped magnetic hysteresis.     

HL-2A装置上边界间歇性事件与湍流粒子输运的统计学研究

通过对粒子概率分布函数的计算,发现在高等离子体密度下边界间歇性事件的爆发频率有所增加。通过条件平均的手段,正负间歇性事件得以区分,并发现了二者在空间上的不同特征。不同密度梯度下的湍流粒子输运计算表明,间歇性事件与湍流粒子输运之间存在密切联系,间歇性事件的存在能够大大增加湍流粒子输运的大小。在高等离子体密度时,间歇性事件的强度有所增加,而与之相应地,湍流粒子输运的大小也有所增强。     

三段加热系统对大尺寸MPOF预制棒一步拉伸工艺

采用自行设计的微结构聚合物光纤专用拉丝系统对大尺寸微结构聚合物光纤预制棒的一步拉伸工艺进行了研究.该微结构聚合物光纤加热系统采用三段式梯度加热,可保持炉内温度的控制准确度在±2℃以内.在保持送料速度与牵引速度恒定、协调的条件下,通过对温度场温度梯度控制优化,确定了最佳拉丝温度组合,并得到了直径规格310 μm、标准偏差为±20 μm的较高质量的微结构聚合物光纤.     

描述复合型疲劳裂纹扩展路径的等效模型

复合型裂纹的扩展路径不同于Ⅰ型裂纹,会沿着与初始裂纹面不同的方向扩展,扩展路径的准确预测对扩展速率的评估具有重要的作用.采用最大周向应力准则和最小应变能密度准则进行扩展路径的预测时,开裂角的误差会使裂纹不断偏离实际路径,造成最终结果的较大偏差.论文将复合裂纹在扩展过程中的弯折裂纹简化为直线裂纹,对简化过程中所产生的误差进行定量分析,并在此基础上提出了一种描述复合型裂纹扩展路径的等效修正模型.将此模型写入ABAQUS扩展有限元模块,实现了基于等效修正模型的疲劳裂纹扩展程序.通过对含中心斜裂纹板的疲劳裂纹扩展试验,验证了该模型的有效性,预测的开裂角与试验结果基本一致,所得到的载荷循环次数低于试验值,对含裂纹结构的寿命评估偏于保守.     

In原子在GaAs(001)表面的成核与扩散研究

近年来,半导体量子点特别是InAs量子点的基本物理性质和潜在应用得到了广泛研究。许多研究者利用InAs量子点结构的改变以调制其光电特性。本文采用液滴外延法在GaAs(001)表面沉积了不同沉积量的In(3 ML、4 ML、5 ML),以研究In的成核机制和表面扩散。实验发现,随着In沉积量的增加,液滴尺寸(包括直径、高度)明显增大。不仅如此,在相同的衬底温度下,沉积量越大,液滴密度越大。利用经典成核理论,计算了GaAs(001)表面In液滴形成的临界厚度为0.57 ML,计算的结果与已报道的实验一致。从In原子在表面的迁移和扩散,以及衬底中Ga和液滴中的In之间的原子互混原理解释了In液滴形成和形貌演化的机理。实验中得到的In液滴临界厚度以及In液滴在GaAs(001)上成核机理,可以为制备InAs量子点提供实验指导。     

Thermally Activated Delayed Fluorescence Triplet State Excitons for High-Performance Organic Photodetectors: A Novel Strategy

Photoinduced charge-trapping is a promising strategy for boosting the photosensitivity of organic photodetectors at the expense of their response time. In addition, they have a low carrier extraction yield due to the formation of low-energy triplet excitons through the recombination of a photogenerated hole–electron pair. Materials with thermally activated delayed fluorescence (TADF) exhibit a long-lived (≈µs) excited spin-triplet nearly iso-energetically aligned with that of an excited spin-singlet, which results in suppressed exciton losses and is widely used in organic light-emitting diodes. The extraction and population of triplet state excitons in TADFs is a sought-after but underexplored aspect of photoinduced gating in photodetectors. A 1,2,3,5-tetrakis(carbazol-9-yl)4,6-Dicyanobenzene (4CzIPN) TADF blend with a high-mobility Poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT-C₁₄) polymer via bulk type-II offset can increase free carrier extraction yield (fast response) and retain trapped electrons in TADF triplet states (high gain). The PBTTT-C₁₄/4CzIPN ultraviolet photodetector device maintains a trade-off between high photogain (≈10³) and fast response time (79 ms) at 300 nm while operating at a shallow dark current (≈pA). Furthermore, the device shows high external quantum efficiency (≈10⁴ %) and detectivity (≈10¹¹ Jones) for low light power (<pW). The innovative application of TADF material can lead to exciting new developments in organic-based high-performance photodetection.