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Design stage plays a decisive role in safety risk management of the whole life cycle for construction projects. However, existing research mostly pay attention to post-accident management and lack pre-management consciousness. Based on the concept of design for safety (DFS), this paper explains how design optimization can enhance the safety performance for construction projects. Firstly, use accident causality theory and trajectory crossing theory to clarify the logical relationship between safety accidents and design process. Then, identify risk sources of safety accidents in deep foundation pit of subway projects and form a safety management knowledge base. Thirdly, based on design and review rules in the knowledge base and improved FEC risk quantification method, quantify the design oriented subway construction safety risks. Finally, use BIM secondary development technology to realize automatic examination and visualization of safety risks. A case study was conducted to verify this research framework. This paper can be a supplement to the existing risk management theoretical research.

Displays play an extremely important role in modern information society, which creates a never-ending demand for the new and better products and technologies. The latest requirements for novel display technologies focus on high resolution and high color gamut. Among emerging technologies that include organic light-emitting diode (OLED), micro light-emitting diode (micro-LED), quantum dot light-emitting diode (QLED), laser display, holographic display and others, QLED is promising owing to its intrinsic high color gamut and the possibility to achieve high resolution with photolithography approach. However, previously demonstrated photolithography techniques suffer from reduced device performance and color impurities in subpixels from the process. In this study, we demonstrated a sacrificial layer assisted patterning (SLAP) approach, which can be applied in conjunction with photolithography to fabricate high-resolution, full-color quantum dot (QD) patterns. In this approach, the negative photoresist (PR) and sacrificial layer (SL) were utilized to determine the pixels for QD deposition, while at the same time the SL helps protect the QD layer and keep it intact (named PR-SL approach). To prove this method’s viability for QLED display manufacture, a 500-ppi, full-color passive matrix (PM)-QLED prototype was fabricated via this process. Results show that there were no color impurities in the subpixels, and the PM-QLED has a high color gamut of 114% National Television Standards Committee (NTSC). To the best of our knowledge, this is the first full-color QLED prototype with such a high resolution. We anticipate that this innovative patterning technique will open a new horizon for future display technologies and may lead to a disruptive and innovative change in display industry.

A series of aldehyde-functionalized dithienylethenes 1b, 1c, 2b and 2c with extended π-conjugated systems have been synthesized by Wittig reaction. Their structures are confirmed by 1H NMR, 13C NMR and HRMS (ESI). As expected, investigation on their photochromic properties indicates that dithienylethenes 1b, 1c, 2b and 2c have good photochromic behaviors with excellent fatigue resistance upon irradiation with UV or visible light. The DFT calculations further validate the differences in their photochromic properties in solution. Furthermore, they can be utilized as versatile building blocks to construct novel near-infrared photochromic materials.

A 6-(4-bromophenoxy)hexyl group linked to carbazole gives crystals that exhibit strong white photoluminescence with an efficiency of 72.6%, a Φ P of 39.5%, and a phosphorescence lifetime of 200 ms., Generally, strong phosphorescence always implies a short luminescence lifetime. So, pure organic molecules with strong persistent phosphorescence at room temperature are rarely explored. Here, a new strategy is used to explore strong persistent phosphorescence of carbazole derivatives through an intermolecular moderate heavy atom effect. Flexible alkyl chains were inserted between the heavy atom and carbazole moieties so as to avoid a strong internal heavy atom affect. The results indicate that the photoluminescence properties of crystals strongly depend on molecular stacking in crystal states. Moreover, seven molecules among eight carbazole derivatives exhibit persistent room-temperature phosphorescence in their crystals and the Φ P values of three compounds exceed 9.5%. Notably, when a 6-(4-bromophenoxy)hexyl group is linked to carbazole, the ambient phosphorescent quantum yield reaches 39.5% and the lifetime is as long as 200 ms. Moreover, it emitted white light with a luminescent efficiency of 72.6% owing to the coexistence of strong fluorescence and phosphorescence.

Ethylene-octene copolymer (POE) samples exposed to I³-radiation under a series of absorbed doses have been investigated using thermal analysis, sol–gel analysis and solid state 13 C nuclear magnetic Resonance (NMR). The chemical shift of POE was assigned and peak evolution as a function of radiation dose was discussed. An obviously evolution is that the peak area of 33.6 ppm decreases as a function of the increase of radiation dose, and at the same time, the peak shape broadens gradually. This indicates that the chain scission occurred between I±-C and branch chain C (methine) or between C1 (the sidegroup hexyl) and branch chain C (methane) after radiation. The chain scission is severer with the increase of absorbed dose.The 13 C NMR spectra of the corresponding gels confirmed the result. The variation in linewidth of the resonance at 33.6 ppm in samples of POE irradiated to different doses was attributed to information of chain, scission, new cross linking, and crystalline components.