Correction:Monodomain Liquid Crystals of Two‑Dimensional Sheets by Boundary‑Free Sheargraphy

In this article Florian Puchtler at affiliation‘University of Bayreuth’,Josef Breu at affiliation‘University of Bayreuth’,and Ziliang Wu at affiliation‘Zhejiang University’was missing from the author Min Cao,Senping Liu,Qingli Zhu,Ya Wang,Jingyu Ma,Zeshen Li,Dan Chang,Enhui Zhu,Xin Ming,Florian Puchtler,Josef Breu,Ziliang Wu,Yingjun Liu,Yanqiu Jiang,Zhen Xu,Chao Gao list.

Review of the influence of freeze-thaw cycles on the physical and mechanical properties of soil

Seasonally frozen soil is a four-phase material and its physical-mechanical properties are more complex compared to the unfrozen soil. Its physical properties changes during the freeze-thaw process; repeated fieeze-thaw cycles change the characteristics of soil, which can render the soil from an unstable state to a new dynamic equilibrium state. The freezing process changes the structttre coupled between the soil particle arrangements, which will change the mechanical properties of the soil. The method of significance and interaction between different fac tors should be considered to measure the influence on the propties of soil under freeze-thaw cycles.

Monodomain Liquid Crystals of Two-Dimensional Sheets by Boundary-Free Sheargraphy

Eliminating topological defects to achieve monodomain liquid crystals is highly significant for the fundamental studies of soft matter and building long-range ordered materials.However,liquid crystals are metastable and sensitive to external stimuli,such as flow,confinement,and electromagnetic fields,which cause their intrinsic polycrystallinity and topological defects.Here,we achieve the monodomain liquid crystals of graphene oxide over 30 cm through boundary-free sheargraphy.The obtained monodomain liquid crystals exhibit large-area uniform alignment of sheets,which has the same optical polarized angle and intensity.The monodomain liquid crystals provide bidirectionally ordered skeletons,which can be applied as lightweight thermal management materials with bidirectionally high thermal and electrical conductivity.Furthermore,we extend the controllable topology of two-dimensional colloids by introducing singularities and disclinations in monodomain liquid crystals.Topological structures with defect strength from−2 to+2 were realized.This work provides a facile methodology to study the structural order of soft matter at a macroscopic level,facilitating the fabrication of metamaterials with tunable and highly anisotropic architectures.

Precise Thermoplastic Processing of Graphene Oxide Layered Solid by Polymer Intercalation

The processing capability is vital for the wide applications of materials to forge structures as-demand.Graphene-based macroscopic materials have shown excellent mechanical and functional properties.However,different from usual polymers and metals,graphene solids exhibit limited deformability and processibility for precise forming.Here,we present a precise thermoplastic forming of graphene materials by polymer intercalation from graphene oxide(GO)precursor.The intercalated polymer enables the thermoplasticity of GO solids by thermally activated motion of polymer chains.We detect a critical minimum containing of intercalated polymer that can expand the interlayer spacing exceeding 1.4 nm to activate thermoplasticity,which becomes the criteria for thermal plastic forming of GO solids.By thermoplastic forming,the flat GO-composite films are forged to Gaussian curved shapes and imprinted to have surface relief patterns with size precision down to 360 nm.The plastic-formed structures maintain the structural integration with outstanding electrical(3.07×10^(5) S m^(−1))and thermal conductivity(745.65 W m^(−1) K^(−1))after removal of polymers.The thermoplastic strategy greatly extends the forming capability of GO materials and other layered materials and promises versatile structural designs for more broad applications.

Numerical simulation of frost jacking response of a single pile considering hydro-thermo-mechanical coupling

Permafrost is widely distributed in China and around the world.In permafrost regions,soil frost heave and thawing are severe and frequent,and can destabilize pile foundations.To this end,a finite element model of a single pile in frozen soil is established to investigate the frost heave and frost jacking response to ensure its safety in the Qinghai-Tibet Plateau.Firstly,a hydro-thermal coupling model of a single pile in frozen soil is established based on coupling parameters and initial and boundary conditions.Then the temperature and moisture distributions are analyzed through the established coupling model.A hydro-thermo-mechanical coupling model is developed by importing the ice content and temperature results.Simulation results indicate that the amount of frost heave is greater at locations closer to the ground surface,and the displacement is smaller for frozen soil that is closer to the side of the pile.The results on frost jacking behavior of piles from this study can serve as a reference for the design,construction and maintenance of foundations.

Key progresses of MOE key laboratory of macromolecular synthesis and functionalization in 2021

In 2021,The MOE Key Laboratory of Macromolecular Synthesis and Functionalization in Zhejiang University had achieved several important results.First,a series of versatile organoboron catalysts were synthesized for ring-opening(co)polymerizations.Second,a catalyst-free polycondensation mechanism was proposed for the production of polyesters with high molecular weights.Third,a co-assembly method that can fabricate films and coatings with controllable structures and properties on various substrates was demonstrated,providing a platform for the construction of novel surface coatings.Forth,facile methods for producing high-productivity poly(propylene carbonate)and semicrystalline polyester have been discovered.And linear non-conjugated polyesters exhibiting yellow-green clusteroluminescence were developed for the first time.Fifth,a supramolecular prodrug nano-assembly strategy has been developed for reactive nitrogen species potentiated chemotherapy.Sixth,a series of tough and stiff supramolecular hydrogels with shape memory properties have been used for information encryption.Seventh,reversible fusion and fission of wet-spun graphene oxide fibers has been successfully achieved.Eighth,three non-conjugated polypeptides were synthesized and the mechanism of clusteroluminescence was studied.Ninth,a series of conducting covalent organic frameworks with high electrical conductivity and carrier mobility have been used as high-performance chemiresistor,electrocatalyst,and organic field-effect transistor.Tenth,the exploration of non-fused electron acceptors,and their photostable mechanism are exemplified for developing high-performance,low-cost and eco-friendly polymer solar cells.Finally,gel-grown long-range ordering bulk-heterojunctions has achieved improved X-ray detector performance.

未冻结和冻结粗砂的本构模型研究

在寒区进行基础设施建设,需要了解土体在未冻结和冻结状态下的力学特性.为研究粗砂在未冻结和冻结状态下的本构行为,本文首先将颗粒破碎率引入砂土的弹性定律和硬化规律中,建立砂土的临界状态模型,对加载过程中的变形和破碎情况进行了研究.同时,采用广义双曲线模型描述了冰夹杂相的力学行为.在基质体和夹杂体本构方程基础上,通过在细观应力和宏观应力之间引入简化的应力集中张量,建立了基于细观力学的冻结砂土模型.通过与不同温度和不同应力路径下的三轴试验结果对比,验证了本文所建立的冻结粗砂宏细观本构模型.

基于环己酮氧化脱氢构建碳-碳与碳-杂键

环己酮是一种廉价易得的大宗有机化工产品,被广泛用作有机合成反应的原料和中间体。脱氢芳构化是合成功能化芳烃的有效途径,使用环己酮作为反应底物,经过亲核加成、脱水和催化脱氢可以将非芳香的有机分子转化为芳香化合物。与传统的芳基化反应相比,该策略避免了苛刻的反应条件和含卤化合物的生产,克服了化学和区域选择性难以控制的难题,为功能化芳烃的合成提供了一条温和、环保的途径。本文就近年来以环己酮为原料,进行氧化脱氢、直接构建碳-碳和碳-杂键,及通过碳-杂键的形成合成杂环化合物的研究现状进行介绍。

Dynamic dispersion stability of graphene oxide with metal ions

Graphene oxide(GO),an important chemical precursor of graphene,can stably disperse in aqueous surrounding and undergo aggregation as metal cations introduced.The usual instability of GO with ions is caused by the shielding effect of ions and crosslinking between GO and ions.However,the dynamic stability of GO under ions exchange still remains unclear.Here,we investigated the dynamic dispersion stability of GO with metal ions and observed a redispersion behavior in concentrated Fe3+solution,other than permanent aggregation.The exchange with Fe3+ions drives the reversion of zeta(ζ)potential and enables the redispersion to individual GO-Fe3+complex sheets,following a dynamic electric double layer(EDL)mechanism.It is found that the specifically strong electrostatic shielding effect and coordination attraction between Fe3+and functional oxygen groups allows the selective redispersion of GO in concentrated Fe3+solution.The revealed dynamic dispersion stability complements our understanding on the dispersive stability of GO and can be utilized to fabricate graphene-metal hybrids for rich applications.

Liquid Crystalline Microdroplets of Graphene Oxide via Microfluidics

Study of stable liquid crystal(LC)microdroplets is of great significance for LC dynamics in con fined space or at topological surface.However,the fabrication of LC microdroplets with diverse shape without ionic gelati on agents still remai ns challe nging due to the fluid instability.Here,we utilize the microfluidic tech no logy to prepare graphe ne oxide(GO)LC microdroplets with various morphologies based on the anomalous rheological property of GO aqueous dispersion.Different from LC of one-dimensional polymer,LC containing two-dimensional GO sheets exhibits considerable viscoelasticity and weak extensibility,resulting from the planar molecular conformation and the absence of intermolecular entangleme nts.The low exte risibility ensures that GO aqueous suspension is discretized into mono dispersed microdroplets rather than thin thread in the microfluidic channels.The large viscoelasticity and ultra-1 ong relaxation time of GO LC enable the diverse stable morphologies of microdroplets.The droplet morphology is well con trolled from sphere to teardrop by modulati ng the competition between GO viscoelasticity and in terfacial ten sion.The two-dimensional GO LC featuri ng unique rheological property provides a novel system for the microfluidic field,and corresponding topological stability enriches the LC dyn amics and ope ns a new pathway for desig ning graphe ne-based materials.

Yield-height correlation and QTL localization for plant height in two lowland switchgrass populations

Switchgrass(Panicum virgatum L.), as a model herbaceous crop species for bioenergy production,is targeted to improve biomass yield and feedstock quality.Plant height is a major component contributing to biomass yield. Accordingly, the objectives of this research were to analyze phenotypic variation for biomass and plant height and the association between them and to localize associated plant height QTLs. Two lowland switchgrass mapping populations, one selfed and another hybrid population established in the field at Perkins and Stillwater,Oklahoma, were deployed in the experiment for two years post establishment. Large genetic variation existed for plant biomass and height within the two populations. Plant height was positively correlated with biomass yield in the selfed population(r = 0.39, P < 0.0001) and the hybrid population(r = 0.41, P < 0.0001). In the selfed population,a joint analysis across all environments revealed 10 QTLs and separate analysis for each environment, collectively revealed 39 QTLs related to plant height. In the hybrid population, the joint analysis across overall environments revealed 35 QTLs and the separate analysis for each environment revealed 38 QTLs. The findings of this research contribute new information about the genetic control for plant height and will be useful for future plant breeding and genetic improvement programs in lowland switchgrass.