Roll-to-Roll Manufacturing of Robust Superhydrophobic Coating on Metallic Engineering Materials

Creating a robust superhydrophobic surface on the conventional engineering materials at mass production is of great importance for self–cleaning, anti–icing, non–wetting surface and low flow resistance in industrial applications. Herein, we report a roll–to–roll strategy to create durable and robust superhydrophobic surfaces with designed micro–/nano– scale hierarchical structures on many conventional engineering materials by combining electrical discharge machining, coating of carbon nanoparticles, and followed by oil penetration and drying. The treated surface shows good superhydrophobic properties with static water contact angle of 170±2o and slide angle of 3±1o. The treated surface also exhibits good resilience and maintains the performance after tested in various harsh conditions including water flushing for several days, sand abrasion, scratching with sandpapers and corrosive solution. Significantly, the superhydrophobic surfaces also shows a high efficiency of self–cleaning properties even after oil–contamination during applications

Recent progress in noble-metal-free electrocatalysts for alkaline oxygen evolution reaction

The practical application of splitting water to generate hydrogen is to a large extent hindered by an oxygen evolution reaction (OER) process. Electrocatalysts with low-cost, high activity, and durability are essential for the low kinetic threshold of the OER. Despite the high active performances of noble metal compound electrocatalysts like IrO2 and RuO2, they are heavily restricted by the high cost and scarcity of noble metal elements. In this context, noble-metal-free electrocatalysts have acquired increasing significance in recent years. So far, a broad spectrum of noble-metal-free electrocatalysts has been developed for improved OER performance. In this review, three types of electrolysis and some evaluation criteria are introduced, followed by recent progress in designing and synthesizing noble-metal-free alkaline OER electrocatalysts, with the classification of metal oxides/(oxy)hydroxides, carbon-based materials, and metal/carbon hybrids. Finally, perspectives are also provided on the future development of the alkaline OER on active sites and stability of electrocatalysts

The socio-spatial design of community and governance: Interdisciplinary urban design in China

This book proposes a new interdisciplinary understanding of urban design in China based on a study of the transformative effects of socio-spatial design and planning on communities and their governance. This is framed by an examination of the social projects, spaces, and realities that have shaped three contexts critical to the understanding of urban design problems in China: the histories of “collective forms” and “collective spaces”, such as that of the urban danwei (work-unit), which inform current community building and planning; socio-spatial changes in urban and rural development; and disparate practices of “spatialised governmentality”. These contexts and an attendant transformation from planning to design and from government to governance, define the current urban design challenges found in the dominant urban xiaoqu (small district) and shequ (community) development model. Examining the histories, transformations, and practices that have shaped socio-spatial epistemologies and experiences in China – including a specific sense of community and place that is rather based on a concrete “collective” than abstract “public” space and underpinned by socialised governance – this book brings together a diverse range of observations, thoughts, analyses, and projects by urban researchers and practitioners. Thereby discussing emerging interdisciplinary urban design practices in China, this book offers a valuable resource for all academics, practitioners, and stakeholders with an interest in socio-spatial design and development

COF-Based Photocatalysts for Enhanced Synthesis of Hydrogen Peroxide

Covalent Organic Frameworks (COFs), with their intrinsic structural regularity and modifiable chemical functionality, have burgeoned as a pivotal material in the realm of photocatalytic hydrogen peroxide (H2O2) synthesis. This article reviews the recent advancements and multifaceted approaches employed in using the unique properties of COFs for high-efficient photocatalytic H2O2 production. We first introduced COFs and their advantages in the photocatalytic synthesis of H2O2. Subsequently, we spotlight the principles and evaluation of photocatalytic H2O2 generation, followed by various strategies for the incorporation of active sites aiming to optimize the separation and transfer of photoinduced charge carriers. Finally, we explore the challenges and future prospects, emphasizing the necessity for a deeper mechanistic understanding and the development of scalable and economically viable COF-based photocatalysts for sustainable H2O2 production

Thermodynamic investigation on para-alkyl chain-substituted phenylbicyclohexyl-type liquid crystals with difluorooxymethylene bridge

We report the results of the study of thermodynamic properties for two difluorooxymethylene-bridged fluorinated liquid crystals. Isobaric heat capacities of the compounds were measured using a Quantum Design Physical Properties Measurement System with heat capacity measurement in the range of 1.9-300 K. Heat capacities of two compounds increased with the temperature increment, and no any thermal anomalies were observed in the whole temperature region, and also the heat capacity values of 5-CCXB(F,F)-F are larger than that of 3-CCXB(F,F)-F due to molecular weight difference even though they are homologs. Standard thermodynamic properties of the liquid crystals were evaluated from the experimental heat capacity temperature dependencies. From the heat capacity results, the standard molar entropies and enthalpies at 298.15 K were determined to be (657.32 +/- 6.57), (741.81 +/- 7.42) J K-1 mol(-1) and (97.17 +/- 0.97), (108.89 +/- 1.09) kJ K-1 mol(-1) for n-CCXB(F,F)-F (n = 3, 5), respectively. Finally, the phase transition sequences and thermodynamical stability of these two fluorinated liquid crystals were performed by differential scanning calorimetry measurements in the temperature range of 253-373 K

Recent progress in noble-metal-free electrocatalysts for alkaline oxygen evolution reaction

The practical application of splitting water to generate hydrogen is to a large extent hindered by an oxygen evolution reaction (OER) process. Electrocatalysts with low-cost, high activity, and durability are essential for the low kinetic threshold of the OER. Despite the high active performances of noble metal compound electrocatalysts like IrO2 and RuO2, they are heavily restricted by the high cost and scarcity of noble metal elements. In this context, noble-metal-free electrocatalysts have acquired increasing significance in recent years. So far, a broad spectrum of noble-metal-free electrocatalysts has been developed for improved OER performance. In this review, three types of electrolysis and some evaluation criteria are introduced, followed by recent progress in designing and synthesizing noble-metal-free alkaline OER electrocatalysts, with the classification of metal oxides/(oxy)hydroxides, carbon-based materials, and metal/carbon hybrids. Finally, perspectives are also provided on the future development of the alkaline OER on active sites and stability of electrocatalysts

Recent progress in noble-metal-free electrocatalysts for alkaline oxygen evolution reaction

The practical application of splitting water to generate hydrogen is to a large extent hindered by an oxygen evolution reaction (OER) process. Electrocatalysts with low-cost, high activity, and durability are essential for the low kinetic threshold of the OER. Despite the high active performances of noble metal compound electrocatalysts like IrO2 and RuO2, they are heavily restricted by the high cost and scarcity of noble metal elements. In this context, noble-metal-free electrocatalysts have acquired increasing significance in recent years. So far, a broad spectrum of noble-metal-free electrocatalysts has been developed for improved OER performance. In this review, three types of electrolysis and some evaluation criteria are introduced, followed by recent progress in designing and synthesizing noble-metal-free alkaline OER electrocatalysts, with the classification of metal oxides/(oxy)hydroxides, carbon-based materials, and metal/carbon hybrids. Finally, perspectives are also provided on the future development of the alkaline OER on active sites and stability of electrocatalysts

An Optoelectronic Equivalent Narrowband Filter for High Resolution Optical Spectrum Analysis

To achieve a narrow bandwidth optical filter with a wide swept range for new generation optical spectrum analysis (OSA) of high performance optical sensors, an optoelectronic equivalent narrowband filter (OENF) was investigated and a swept optical filter with bandwidth of several MHz and sweep range of several tens of nanometers was built using electric filters and a sweep laser as local oscillator (LO). The principle of OENF is introduced and analysis of the OENF system is presented. Two electric filters are optimized to be RBW filters for high and medium spectral resolution applications. Both simulations and experiments are conducted to verify the OENF principle and the results show that the power uncertainty is less than 1.2% and the spectral resolution can reach 6 MHz. Then, a real-time wavelength calibration system consisting of a HCN gas cell and Fabry–Pérot etalon is proposed to guarantee a wavelength accuracy of ±0.4 pm in the C-band and to reduce the influence of phase noise and nonlinear velocity of the LO sweep. Finally, OSA experiments on actual spectra of various optical sensors are conducted using the OENF system. These experimental results indicate that OENF system has an excellent capacity for the analysis of fine spectrum structures