White‐Light Emission Strategy of a Single Organic Compound with Aggregation‐Induced Emission and Delayed Fluorescence Properties

A novel white‐light‐emitting organic molecule, which consists of carbazolyl‐ and phenothiazinyl‐substituted benzophenone (OPC) and exhibits aggregation‐induced emission‐delayed fluorescence (AIE‐DF) and mechanofluorochromic properties was synthesized. The CIE color coordinates of OPC were directly measured with a non‐doped powder, which presented white‐emission coordinates (0.33, 0.33) at 244 K to 252 K and (0.35, 0.35) at 298 K. The asymmetric donor–acceptor–donor′ (D‐A‐D′) type of OPC exhibits an accurate inherited relationship from dicarbazolyl‐substituted benzophenone (O2C, D‐A‐D) and diphenothiazinyl‐substituted benzophenone (O2P, D′‐A‐D′). By purposefully selecting the two parent molecules, that is, O2C (blue) and O2P (yellow), the white‐light emission of OPC can be achieved in a single molecule. This finding provides a feasible molecular strategy to design new AIE‐DF white‐light‐emitting organic molecules.     

A Porous Tricyclooxacalixarene Cage Based on Tetraphenylethylene

A quadrangular prismatic tricyclooxacalixarene cage 1 based on tetraphenylethylene (TPE) was efficiently synthesized by a one‐pot S_NAr condensation reaction. As a result of the porous internal structure in the solid state, cage 1 exhibited a good CO₂ uptake capacity of 12.5 wt % and a high selectivity for CO₂ over N₂ adsorption of 80 (273 K, 1 bar) with a BET surface area of 432 m² g^?1. Formation of cage 1 led to the fluorescence of TPE being switched on in solution. The system was employed as a single‐molecule platform to study the mechanism of aggregation‐induced emission (AIE) by examining the restriction of intramolecular rotation (RIR).     

Organic Crystals with Near‐Infrared Amplified Spontaneous Emissions Based on 2′‐Hydroxychalcone Derivatives: Subtle Structure Modification but Great Property Change

A series of highly efficient deep red to near‐infrared (NIR) emissive organic crystals 1 – 3 based on the structurally simple 2′‐hydroxychalcone derivatives were synthesized through a simple one‐step condensation reaction. Crystal 1 displays the highest quantum yield (Φ_f) of 0.32 among the reported organic single crystals with an emission maximum (λ_em) over 710 nm. Comparison between the bright emissive crystals 1 – 3 and the nearly nonluminous compounds 4 – 7 clearly gives evidence that a subtle structure modification can arouse great property changes, which is instructive in designing new high‐efficiency organic luminescent materials. Notably, crystals 1 – 3 exhibit amplified spontaneous emissions (ASE) with extremely low thresholds. Thus, organic deep red to NIR emissive crystals with very high Φ_f have been obtained and are found to display the first example of NIR fluorescent crystal ASE.     

Synthesis and Design of Aggregation‐Induced Emission Surfactants: Direct Observation of Micelle Transitions and Microemulsion Droplets

The direct visualization of micelle transitions is a long‐standing challenge owing to the intractable aggregation‐caused quenching of light emission in the micelle solution. Herein, we report the synthesis of a surfactant with a tetraphenylethene (TPE) core and aggregation‐induced emission (AIE) characteristics. The transition processes of surfactant micelles and the microemulsion droplets (MEDs) formed by the surfactant with a TPE core were clearly visualized by a high‐contrast fluorescence imaging method. The fluorescence intensity of the MEDs decreased as the size of MEDs increased as a result of weakening of the restriction of intramolecular rotation (RIR). The results of this study deepen our understanding of micelle‐transition processes and provide solid evidence in favor of the hypothesis that the AIE phenomenon has its origin in the RIR of fluorophores in the aggregate state.     

Analytical potential of a laser ablation–glow discharge–optical emission spectrometry system for the analysis of conducting and insulating materials

The analytical capabilities of a glow discharge (GD) as a secondary source for excitation/ionization of the material provided by laser ablation (LA) have been compared to conventional laser induced breakdown spectroscopy (LIBS). In LA–GD both sources can be independently adjusted to optimize the sampling process and then its subsequent excitation. This could involve a number of analytical performance advantages, such as reduced matrix dependence, greater precision and sensitivity than those encountered in LIBS. For such purpose, an ablation chamber design including two electrodes to generate the GD discharge has been built and assayed. A comparison between LIBS and LA–GD–OES has been carried out, both, under reduced argon and helium atmospheres. Different sets of samples (conducting reference materials, glass and fluorine pellets) have been used to evaluate the novel coupled technique. The LA–GD coupled system has shown to provide lower detection limits. In addition, best linear correlations between intensities and concentrations and lower matrix effects have also been found using the coupled system. Moreover, special advantages of the LA–GD–OES have also been demonstrated for the analysis of fluorine.     

Experimental study on the fiber pull-out of composites using digital gradient sensing technique

A method to measure the stress field at the fiber tip in the fiber pull out test was proposed by using a digital gradient sensing technique. First, the principle of digital gradient sensing is introduced, and the non-contact optical system of digital gradient sensing developed. Then, a fiber reinforced composite model specimen, where a nail was inserted in epoxy resin to act as a fiber, was performed, and a pull out test was conducted on the specimen using the digital gradient sensing technique. Finally, the angular deflections contour at the fiber tip was obtained, and the stress intensity factor was extracted from the angular deflections. The results show that the stress intensity factor at the fiber tip extracted from the angular deflections agreed with the results calculated by the finite element method.     

新型核素~(64)Cu标记硝基咪唑类肿瘤乏氧显像剂及正电子发射断层扫描显像研究

采用新型核素64Cu标记了含丙烯胺肟[Pn AO(3,3,9,9-Tetramethyl-4,8-diazaundecane-2,10-dione Dioxime)]结构的硝基咪唑类乏氧显像剂Pn AO-1-(2-nitroimidazole)[BMS181321],通过优化反应条件,于室温下反应10 min后即得到高放化纯度和高比活度的标记化合物64Cu-BMS181321.目标产物经放射性高效液相色谱检测验证和体外稳定性实验确认后,通过尾静脉注射到人源胰腺癌(PANC-1细胞系)裸鼠体内,分别于注射显像剂4和8 h后进行小动物正电子发射断层扫描显像(Micro-PET).结果表明,4 h左右肿瘤乏氧区域有良好的放射性浓聚.64Cu-BMS181321的合成及其分子显像研究开创了64Cu标记硝基咪唑类乏氧显像剂进行乏氧显像的先例,经进一步药物临床实验评价后,64Cu-BMS181321有望成为具有良好前景的PET乏氧显像药物.     

大气压下甲烷火花放电制乙炔和合成气

用大气压下火花放电方法和发射光谱原位诊断技术, 对CH₄直接转化制乙炔和间接转化制合成气进行了研究, 并与介质阻挡放电进行了比较。结果表明, 火花放电具有能量效率高的突出优点, 能够高效地将CH₄活化成C原子、H原子和C₂等活泼物种。当CH₄单独进料时, 能得到以C₂H₂为主的烃类产物。当CH₄与CO₂和O₂共进料时, 能得到H₂/CO比值可调的合成气产物。在用火花放电转化CH₄和CO₂制合成气时, 添加O₂能够避免反应器的结炭问题, 反应温度只需225 ℃, 与常规催化法相比具有明显的低温优势。     

Sonochemical Synthesis of Gold Nanoparticles by Using High Intensity Focused Ultrasound

The sonochemical synthesis of gold nanoparticles (GNPs) with different shapes and size distributions by using high‐intensity focused ultrasound (HIFU) operating at 463 kHz is reported. GNP formation proceeds through the reduction of Au³⁺ to Au⁰ by radicals generated by acoustic cavitation. TEM images reveal that GNPs show irregular shapes at 30 W, are primarily icosahedral at 50 W and form a significant amount of nanorods at 70 W. The size of GNPs decreases with increasing acoustic power with a narrower size distribution. Sonochemiluminescence images help in the understanding of the effect of HIFU in controlling the size and shapes of GNPs. The number of radicals that form and the mechanical forces that are generated control the shape and size of the GNPs. UV/Vis spectra and TEM images are used to propose a possible mechanism for the observed effects. The results presented demonstrate, for the first time, that the HIFU system can be used to synthesise size‐ and shape‐controlled metal nanoparticles.     

Tuning the Upconversion Luminescence Lifetimes of KYb2F7:Ho3+ Nanocrystals for Optical Multiplexing

Conventional luminescent color coding is limited by spectral overlap and the interference of background fluorescence, thus restricting the number of distinguishable identities that can be used in practice. Here, we demonstrate the possibility of generating diverse time‐domain codes, specially designed for a single emission band, using lanthanide‐doped upconversion nanocrystals. Based on the knowledge of concentration quenching, the upconversion luminescence kinetics of KYb₂F₇: Ho³⁺ nanocrystals can be precisely controlled by modifying the dopant concentration of Ho³⁺ ions, resulting in a tunable emission lifetime from 75.8 to 1944.5 μs, which suggests the practicality of these time‐domain codes for optical multiplexing.