Exploring the methods on improving CH_(4) delivery performance to surpass the Advanced Research Project Ageney-Energy target

CH_(4) storage associated with adsorbed natural gas(ANG)technology is an issue attracting great concern.Following the Advanced Research Project Agency-Energy(ARPA-E)targeted deliverable capacity of 315 cm^(3)·cm^(-3)(STP),hundreds of thousands of materials have been experimentally or theoretically evaluated,while the best results still show a 35% gap from the target.Moreover,recent theoretical research reveals that the target is beyond the possibility that real materials can be designed.To get rid of the awkward situation,we make attempts on investigating the CH_(4) delivery performance under other operation conditions.Methods of raising the discharge temperature(to infinite high)or elevating the storage pressure(to 25 MPa)have been proved to show limited effectiveness.In this work,it is found that the ARPA-E target can be achieved by using a decreasing storage temperature strategy.By taking 280 CoRE(computation-ready,experimental)COFs(covalent organic frameworks)as ANG materials,when reduce the storage temperature to 190.6 K,the highest deliverable capacity can reach 392 cm^(3)·cm^(-3)(STP),and 16.1% CoRE COFs can surpass the target.The target is also achievable when storage at 220 K.Structure performance relationships study shows strong correlation between deliverable capacity and void fraction.Hence,120 hypothetical COFs are generated to ascertain the optimum void fraction.In addition,the performance of 2D-COFs can be greatly enhanced by increasing the interlayer spacings,e.g.CH_(4) deliverable capacity(storage at 190.6 K)of ATFG-COF can be improved from 239 to 411 cm^(3)·cm^(-3)(STP)when interlayer spacing is enlarged to 1.65 nm.

Integrated solid-state lidar employing orthogonal polarizations and counterpropagation[Invited]

Light detection and ranging(lidar)has attracted significant interest as a sensing technology for its ability to achieve highresolution imaging and wide-angle perception.However,conventional lidar systems,built with separate components,are often bulky,expensive,complex,and prone to instability.In contrast,solid-state lidar,based on silicon photonics technology,offers a solution with its compact size,less expense,low energy consumption,and improved reliability.However,achieving precise beam steering remains a critical challenge for integrated lidar systems.Various methods have been demonstrated for beam steering,which is one of the simplest and most efficient approaches that utilize wavelength tuning with a grating coupler antenna.In this review,we introduce the fundamental principle of optical phased array for beam steering and provide an overview of the recent advancements in integrated solid-state lidars utilizing orthogonal polarizations and counterpropagation to enhance beam-steering range and angular resolution.