Controllable amorphization and morphology engineering on mixed-valence MOFs for ultra-fast and high-stability near-pseudocapacitance Li+ storage.

Coulombic efficiency (CE) and rate capability are crucial parameters for advanced secondary batteries. Herein, for the first time, we report controllable amorphization and morphology engineering on mixed-valence Fe(II,III)-MOFs from the crystalline to amorphous state and micro-clustered to hollow nano-spherical geometry through valence manipulation by a dissolved oxygen-mediated pathway. The disordered structure and the hollow nanostructure can endow the MOFs with the highest initial CE (>80%) to date for MOF electrodes, and ultrafast and super-stable near-pseudocapacitance lithium storage. These findings can provide new ideas for the engineering of MOF systems for application in LIBs.

Defluorinative Haloalkylation of Unactivated Alkenes Enabled by Dual Photoredox and Copper Catalysis.

A three-component defluorinative haloalkylation of alkenes with trifluoromethyl compounds and TBAX (X = Cl, Br) via dual photoredox/copper catalysis is reported. The mild conditions are compatible with a wide array of activated trifluoromethyl aromatics bearing diverse substituents, and various nonactivated terminal and internal alkenes, enabling straightforward access to synthetically valuable γ-gem-difluoroalkyl halides with high efficiency. Mechanistic studies indicate that the [Cu] complexes not only serve as XAT catalysts but also facilitate the SET reduction of trifluoromethyl groups by photocatalysts. Additionally, the resulting alkyl halide products can serve as versatile conversion intermediates for the synthesis of a diverse range of γ-gem-difluoroalkyl compounds.

A multi-objective optimization model of urban passenger transportation structure under low-carbon orientation considering participating subjects.

The optimization of urban passenger transport structure can effectively save energy and reduce the carbon emission of transport. However, the carbon emission and energy consumption generated by the construction of transport projects are worthy of attention. In this paper, a multi-objective optimization model of urban passenger transport structure oriented to low carbon is proposed considering passenger, operator, and construction. The optimal solution of the model is obtained based on the NSGA-II algorithm, and the validity of the model is verified with a case of Qingdao. The optimal ratio of Qingdao passenger traffic structure considering only the passenger perspective (PS), considering the passenger and operator (POS), and considering the three parties together (POCS) is obtained, respectively. The results show that the optimal structures obtained by the PS, POS, and POCS models increase the public transport passenger share by 12.74%, 20.74%, and 23.70%, compared with the actual values. From both the supply and demand sides, there has been an increase in the passenger share of public transport. The POS model is more suitable for solving structural optimization problems that do not involve construction carbon emissions in the short term. The POCS model is more suitable for long-term comprehensive structural optimization problems. The results of the study provide a reference basis for optimizing the urban passenger transport structure.

Multi-objective cold chain logistic distribution center location based on carbon emission.

The issues of food safety and environmental protection are attracting more and more attention. Everyday, a large number of cold chain products are delivered from suppliers to customers. The cold chain products require refrigeration equipment in delivery and should be delivered to customers as soon as possible. Therefore, the challenge of reducing carbon emission and improving the customer satisfaction should be solved. This study presents the impact of carbon emission, customer satisfaction, construction cost, and operation cost on the location of cold chain logistics distribution center. A multi-objective location model for cold chain logistics distribution center considering carbon emission is established. The carbon emission equivalent cost model considers the dynamic carbon emission during transportation and the static carbon emission of the distribution center. The penalty cost under the time window is introduced into the penalty cost model of customer satisfaction, which represents a multi-objective mixed-integer linear programming problem. A non-dominated sorting genetic algorithm II (NSGA-II) is used to design the program through double-layer composite coding. NSGA-II uses a fast non-dominated sorting approach to reduce the computational complexity of non-dominated sorting. This algorithm uses the elitist control strategy, which does not need to share parameters and is more efficient in the multi-objective optimization process. The numerical results show that the proposed algorithm can generate appropriate Pareto solutions for all objectives.

A Collaborative Data Collection Scheme Based on Optimal Clustering for Wireless Sensor Networks.

In recent years, energy-efficient data collection has evolved into the core problem in the resource-constrained Wireless Sensor Networks (WSNs). Different from existing data collection models in WSNs, we propose a collaborative data collection scheme based on optimal clustering to collect the sensed data in an energy-efficient and load-balanced manner. After dividing the data collection process into the intra-cluster data collection step and the inter-cluster data collection step, we model the optimal clustering problem as a separable convex optimization problem and solve it to obtain the analytical solutions of the optimal clustering size and the optimal data transmission radius. Then, we design a Cluster Heads (CHs)-linking algorithm based on the pseudo Hilbert curve to build a CH chain with the goal of collecting the compressed sensed data among CHs in an accumulative way. Furthermore, we also design a distributed cluster-constructing algorithm to construct the clusters around the virtual CHs in a distributed manner. The experimental results show that the proposed method not only reduces the total energy consumption and prolongs the network lifetime, but also effectively balances the distribution of energy consumption among CHs. By comparing it o the existing compression-based and non-compression-based data collection schemes, the average reductions of energy consumption are 17.9% and 67.9%, respectively. Furthermore, the average network lifetime extends no less than 20-times under the same comparison.

The presence of genogroup II norovirus in retail shellfish from seven coastal cities in China.

Noroviruses (NoVs) are commonly occurring pathogens that cause gastroenteritis. Outbreaks of viral diseases have often been ascribed to the consumption of contaminated shellfish. Our objective was to evaluate the presence and contamination levels of NoV in shellfish sold at seafood markets in China. We tested 840 shellfish samples (Crassostrea gigas, Mytilus edulis, Azumapecten farreri, SinoNoVacula constricta, Scapharca subcrenata, Ruditapes philippinarum) that were collected from seven cities around the Yellow and Bohai Seas in China between December 2009 and November 2011. We used real-time RT-PCR to detect NoV in purified concentrates from the stomach and digestive diverticula of these shellfish. NoV was detected in 19.35 % (N = 155), 16.67 % (N = 114), 5.70 % (N = 158), 8.82 % (N = 136), 13.74 % (N = 131), and 16.44 % (N = 146) of oyster, mussel, scallop, razor clam, ark shell, and clam samples, respectively. The average detection rate was 13.33 % (112/840). Nucleotide sequencing of the NoV RT-PCR products demonstrated that all strains belonged to NoV genotype GII.12, except two that belonged to GI.3. More than 10² copies of the NoV genome were detected in 69 of 112 positive shellfish samples. Our results suggest that ~13 % of shellfish harbor NoV, and GII.12 NoV is the primary strain in shellfish purchased at markets in seven coastal cities in China.