STCF conceptual design report (Volume 1): Physics & detector

The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics community.It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5×10^(35) cm^(–2)·s^(–1) or higher.The STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory—the BEPCII,providing a unique platform for exploring the asymmetry of matter-antimatter(charge-parity violation),in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions,as well as searching for exotic hadrons and physics beyond the Standard Model.The STCF project in China is under development with an extensive R&D program.This document presents the physics opportunities at the STCF,describes conceptual designs of the STCF detector system,and discusses future plans for detector R&D and physics case studies.

In Situ Wood Delignification toward Sustainable Applications

CONSPECTUS:As one of the most abundant and versatile natural materials on Earth,recently wood has attracted tremendous attention from scientists and engineers due to its outstanding advantages,including hierarchically porous microstructure,high mechanical strength,environmental friendliness,renewability,and biodegradability.Wood’s hierarchically porous structure and chemical components(e.g.,cellulose,hemicelluloses,and lignin)enable its mechanical,ionic,optical,and thermal properties to be tuned via physical,chemical,and/or thermal modifications.Among these various approaches,the chemical delignification of bulk wood is the most fascinating,in which the majority of lignin and hemicelluloses is removed while leaving the cellulose intact,maintaining wood’s physical integrity and hierarchical structure.This delignified structure is unique,composed of hollow,aligned channels made up of cellulose microfibrils,and particularly attractive given its origin from a sustainable and renewable resource.As a result,delignified wood has attracted increasing attention for applications that go far beyond traditional wood utilization,such as lightweight yet strong structural materials,energy storage and conversion,environmental remediation,flexible electronics,and bioengineering.This Account reviews recent developments in bulk wood delignification strategies toward the achievement of such advanced wood technologies for sustainable applications,with a focus on the research in our group.Similar to chemical pulping and bleaching,wood delignification involves a series of nucleophilic reactions based on alkaline Na2SO3 or Na2S systems(i.e.,chemical pulping)or electrophilic,radical,and oxidation reactions based on H2O2,ClO2,or NaClO systems(i.e.,chemical bleaching)to deconstruct,fragment,and promote the hydrophilicity of lignin macromolecules,which finally make lignin easier to be removed.We discuss the structure and properties of partially and near-completely delignified wood,with a focus on process-structure−property relationships.The resulting delignified wood materials,with tunable structure and properties,demonstrate various advanced functions,in a wide range of advanced applications,such as building and construction,green energy,and electronics.Finally,the potential challenges and appealing perspectives of in situ wood delignification are discussed.In situ wood delignification,as a powerful modification strategy,has speeded up the development of advanced wood technologies and wood-based functional materials and products.