Conventional technology for the purification of organic solvents requires massive energy consumption, and to reduce such expending calls for efficient filtration membranes capable of high retention of large molecular solutes and high permeance for solvents. Herein, we report a surface-initiated polymerization strategy through C-C coupling reactions for preparing conjugated microporous polymer (CMP) membranes. The backbone of the membranes consists of all-rigid conjugated systems and shows high resistance to organic solvents. We show that 42-nm-thick CMP membranes supported on polyacrylonitrile substrates provide excellent retention of solutes and broad-spectrum nanofiltration in both non-polar hexane and polar methanol, the permeance for which reaches 32 and 22 l m h bar, respectively. Both experiments and simulations suggest that the performance of CMP membranes originates from substantially open and interconnected voids formed in the highly rigid networks.

Notched components are commonly used in engineering structures, where stress concentration may easily lead to crack initiation and development. The main goal of this work is to develop a simple numerical method to predict the strength and crack‐growth‐path of U‐notched specimens made of brittle materials. For this purpose, the Fragile Points Method (FPM), as previously proposed by the authors, has been augmented by an interface debonding model at the interfaces of the FPM domains, to simulate crack initiation and development. The formulations of FPM are based on a discontinuous Galerkin weak form where point‐based piece‐wise‐continuous polynomial test and trial functions are used instead of element‐based basis functions. In this work, the numerical fluxes introduced across interior interfaces between subdomains are postulated as the tractions acting on the interface derived from an interface debonding model. The interface damage is triggered when the numerical flux reaches the interface strength, and the process of crack‐surface separation is governed by the fracture energy. In this way, arbitrary crack initiation and propagation can be naturally simulated without the need for knowing the fracture‐patch before‐hand. Additionally, a small penalty parameter is sufficient to enforce the weak‐form continuity condition before damage initiation, without causing problems such as artificial compliance and numerical ill‐conditioning. As validations, the proposed FPM method with the interface debonding model is used to predict fracture strength and crack‐growth trajectories of U‐notched structures made of brittle materials, which is useful but challenging in engineering structural design practices.

Treetop walkways are unique trail constructions. Their support structure suspends a walkway platform several meters from the ground, shuttling among the canopies of trees in the forest. Many countries have built canopy trails for forest recreation, tourism, and other uses. In certain cities, the treetop walkway is no longer a single building unit or forest trail in the narrow sense, and is planned as a multi-functional urban public landscape. This study reviews the development of treetop and elevated forest trails, introduces several representative cases, and provides a comprehensive reference point that fills previous research gaps. We also analyze the Fu Forest Trail, the most representative treetop walkway in China through, inter alia, its modular system, elevated structural, and design appearance. We explore the background and application of treetop trails that connect residents and the environment as a multifunctional urban public landscape in China, and related future research directions. We conclude that treetop walkways have many distinct advantages, and are becoming trendy in forest trail development; there is excellent potential to transform them creatively and innovatively into high-quality forest infrastructure or urban public landscape for public benefit.

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By combining non-equilibrium molecular dynamics(NEMD), umbrella sampling, and weighted histogram analysis method(WHAM), we calculated the potential of mean force of histidine peptide moving over a self-assembly structure. The reaction coordinate is along the main chain direction of the histidine peptide in the self-assembly structure. It is found that the energy needed for the histidine peptide with 3 and 5 residues while moving along the reaction coordinate is around -2.2 kCal/mol and -7.4 kCal/mol, respectively. And the histidine peptide crawls along the reaction coordinate, performing a snake-like movement. This result could illustrate how histidine peptide adjusts its position during self-assembly process.

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