Design and fabrication of lutetium aluminum silicate glass and nanostructured glass for radiation detection

Flexible scintillating fiber plays an important role in X-ray radiation monitoring and high-resolution medical imaging, while construction of scintillating fiber derived from the commercial material system meet with limited success. Here, we report the design and successful fabrication of the Ce-activated lutetium aluminum silicate glass, nanostructured glass, and fiber, and explore their scintillating properties. The scintillating glass with optimized composition and optical properties is determined. The crystallization behavior of lutetium aluminum silicate glass is studied and the nanostructured glass embedded with orthorhombic Lu₂Si₂O₇ phase is successfully constructed for the first time. Importantly, the crystalline layer thickness of the nanostructured glass can be finely tuned and ~172.89% enhancement in the scintillating performance can be achieved. Furthermore, the fiber with large sized core is fabricated and its radiation response properties are tested. The results show that it exhibits high sensitivity and its scintillating emission is lineally dependent on the X-ray power, indicating the potential application for radiation detection.     

人工智能赋能在线实验教学行为分析

教学行为分析作是教学质量分析的重要组成部分，也是教学引导与反馈机制的重要依据。文章阐述了人工智能（AI）的含义及发展历程，重点分析总结了教学行为分析方法及AI在教学行为分析上的应用。文章以东南大学电工电子在线实验为研究平台，探索分析了AI技术在实验教学行为分析上的可行性，梳理了基于专家系统的在线实验分析系统的设计思路，充分探讨了“智能”教育在实验教学中的深刻内涵。     

Understanding the asymmetric perceptions of smartphone security from security feature perspective: A comparative study

Smartphones are being used and relied on by people more than ever before. The open connectivity brings with it great convenience and leads to a variety of risks that cannot be overlooked. Smartphone vendors, security policy designers, and security application providers have put a variety of practical efforts to secure smartphones, and researchers have conducted extensive research on threat sources, security techniques, and user security behaviors. Regrettably, smartphone users do not pay enough attention to mobile security, making many efforts futile. This study identifies this gap between technology affordance and user requirements, and attempts to investigate the asymmetric perceptions toward security features between developers and users, between users and users, as well as between different security features. These asymmetric perceptions include perceptions of quality, perceptions of importance, and perceptions of satisfaction. After scoping the range of smartphone security features, this study conducts an improved Kano-based method and exhaustively analyzes the 245 collected samples using correspondence analysis and importance satisfaction analysis. The 14 security features of the smartphone are divided into four Kano quality types and the perceived quality differences between developers and users are compared. Correspondence analysis is utilized to capture the relationship between the perceived importance of security features across different groups of respondents, and results of importance-satisfaction analysis provide the basis for the developmental path and resource reallocation strategy of security features. This article offers new insights for researchers as well as practitioners of smartphone security.     

Suppressed Lattice Disorder for Large Emission Enhancement and Structural Robustness in Hybrid Lead Iodide Perovskite Discovered by High-Pressure Isotope Effect

The soft nature of organic–inorganic halide perovskites renders their lattice particularly tunable to external stimuli such as pressure, undoubtedly offering an effective way to modify their structure for extraordinary optoelectronic properties. Here, using the methylammonium lead iodide as a representative exploratory platform, it is observed that the pressure-driven lattice disorder can be significantly suppressed via hydrogen isotope effect, which is crucial for better optical and mechanical properties previously unattainable. By a comprehensive in situ neutron/synchrotron-based analysis and optical characterizations, a remarkable photoluminescence (PL) enhancement by threefold is convinced in deuterated CD₃ND₃PbI₃, which also shows much greater structural robustness with retainable PL after high peak-pressure compression–decompression cycle. With the first-principles calculations, an atomic level understanding of the strong correlation among the organic sublattice and lead iodide octahedral framework and structural photonics is proposed, where the less dynamic CD₃ND₃⁺ cations are vital to maintain the long-range crystalline order through steric and Coulombic interactions. These results also show that CD₃ND₃PbI₃-based solar cell has comparable photovoltaic performance as CH₃NH₃PbI₃-based device but exhibits considerably slower degradation behavior, thus representing a paradigm by suggesting isotope-functionalized perovskite materials for better materials-by-design and more stable photovoltaic application.     

Solvothermal synthesis of zirconia nanomaterials: Latest developments and future

Due to excellent mechanical properties, thermal stability and catalytic characteristics, zirconia is considered as the most important ceramic materials. Different crystal forms make zirconia play a huge role in solid electrolyte fuel cells, catalysts, thermal barrier coatings, denture materials, mobile phone backplanes, etc. The purpose of this paper is to provide a comprehensive review about solvothermal synthesis of nano-zirconia. Firstly, the reactors and systems of solvothermal synthesis in recent years are introduced. Especially, the advancement of continuously flowing microreactors and field-coupled systems are analyzed. Secondly, influencing factors of zirconia solvothermal synthesis are discussed. In addition, solvent effects on the synthesis of nano-zirconia products are clarified, and suggestions for solvent selection are given. Furthermore, the design and mechanism of solvothermal synthesis of zero-, one-, two-and three-dimensional zirconia nanostructures are revealed. Simultaneously, experimental methods and kinetic studies are summarized. Finally, potential applications and challenges are presented for future research directions.     

A tool for mass transfer evaluation in packed-bed columns for chemical engineering students

This paper presents a Microsoft Excel tool to calculate liquid-gas mass transfer coefficients in packed towers to support numerical design activities in the courses of Unit Operations for Industrial Process and Sustainable Process Design for the Master’s degree in Chemical Engineering of the University of Naples Federico II (Italy).The Mass Transfer Solver Tool (MT Solver Tool) uses several available models to estimate, separately, the values of liquid and gas mass-transfer coefficients and the wet surface area for 144 random and structured packings of interest for absorption/stripping and distillation processes. In addition, a separate spreadsheet can be used in a user-defined mode, to evaluate the mass transfer coefficients with new packing types or to interpret experimental data when the geometrical and physical characteristics of the packing are known. Eventually, the tool is supplied with a data library, where packing geometry and model fitting parameters can be retrieved.The software is aimed to support students and educators in the Unit Operations for Industrial Process and Sustainable Process Design courses. In particular, this is meant to be an example on how the accuracy of design algorithms adopted in unit operation processes is affected by the use of the underpinning correlations for mass transfer rate or pressure drops. Besides, this is aimed to encourage comparison of different correlations when exact field data are not available. Besides, chemical engineers and researchers interested in packed columns design and modelling data may also benefit from the utilization of the software. The MT Solver Tool was introduced to students in a dedicated tutorial lesson after lecturers on packed column design algorithms for distillation, absorption and stripping. Most of the students of the course participated to a group training aimed to simulate the design of an absorption column supported by the MT Solver Tool providing feedback on its application.After the training, an anonymous survey was proposed to the students to monitor the approval rating of the proposed activity and the use of the MT Solver Tool software to support numerical calculations.     

Soluble network polymers based on trifluoropropyl-substituted open-cage silsesquioxane: Synthesis,properties, and application for surface modifiers

Fluorinated completely condensed polyhedral oligomeric silsesquioxanes (F-CC-POSSs) are widely utilized as surface modifiers for polymeric materials because of their polyhedral and fluorine-rich structures, which generate polymers with lower surface energies under molecular-level control. In contrast, their derivatives, fluorinated incompletely condensed or open-cage POSSs (F-IC-POSSs), have similarly intriguing structures, but their utilization for polymer synthesis remains undeveloped. Herein, fluorinated network polymers were prepared based on a 3,3,3-trifluoropropyl-substituted IC-POSSs via hydrosilylation polymerization with isobutyl- and phenyl-substituted IC-POSS under optimized conditions. In addition to their good thermal stability and tunable refractive indices, these polymers exhibited solution processability and their casting films showed excellent optical transparency, indicating their potential for constructing fluorinated polymers. Their utilization as surface modifiers was examined by addition to poly(methylmethacrylate) (PMMA) films. Intriguingly, modified PMMA films with 2.0 and 0.5 wt% addition showed similar hydrophobicity and surface energies to the films prepared with only fluorinated network polymers.     

Piezoelectric properties of PVDF-conjugated polymer nanofibers

This study presents the development and characterization of PVDF-conjugated polymer nanofiber-based systems. Five different conducting polymers (CPs) were synthesized successfully and used to create the nanofiber systems. The CPs used are polyaniline (PANI), polypyrrole (PPY), polyindole (PIN), polyanthranilic acid (PANA), and polycarbazole (PCZ). Nanofiber systems were produced utilizing the Forcespinning® technique. The nanofiber systems were developed by mechanical stretching. No electrical field or post-process poling was used in the nanofiber systems. The morphology, structure, electrochemical and piezoelectric performance was characterized. All of the nanofiber PVDF/CP systems displayed higher piezoelectric performance than the fine fiber PVDF systems. The PVDF/PPY nanofiber system displays the highest piezoelectric performance of 15.56 V. The piezoelectric performance of the PVDF/CP nanofiber systems favors potential for an attractive source of energy where highly flexible membranes could be used in power actuators, sensors and portable, and wireless devices to mention some.