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Emerging artificial Bouligand-type structural materials

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National Science Review 2018年第6期5卷 786-787页

作者： helmut clfen Department of chemistry University of Konstanz

Until now, the demand for lighter,stronger, tougher and more wearresistant materials has remained unmet for diverse applications, as many structural materials prepared by traditional engineering manufacturing techniqu... 详细信息

关键词： Emerging artificial Bouligand-type structural materials

Bivalve hinge reveals the structural design of fatigue-resistant deformable ceramic materials

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Science china Materials 2023年第10期66卷 4141-4142页

作者： helmut colfen Physical chemistry University of KonstanzUniversitätsstraße 10Box 714 D-78457 KonstanzGermany

关键词： composites ceramic structural

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Surface nanocrystallization of wood particles from biomass waste for regenerated isotropic wood with excellent properties

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National Science Review 2021年第8期8卷 134-135页

作者： helmut c?lfen Department of chemistry University of Konstanz

Materials are the cornerstone of human society. Environmentally friendly and sustainable bio-based materials are the key to achieving sustainable development, which is urgently needed to meet global challenges [1–4]. Different from petroleum-based materials, bio-based plant materials are derived from carbon dioxide in the atmosphere, which is fixed by the photosynthesis of plants to form biomaterials like wood. The use of these materials by humans can be traced back to ancient times. However,

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Bamboo nodes show nature's wisdom

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National Science Review 2023年第2期10卷 86-87页

作者： helmut c?lfen Department of chemistry University of Konstanz

Bamboo(Phyllostachys edulis) is a biological structural material featuring tall stalks and excellent mechanical properties [1].It has been applied to many engineering areas such as construction,transportation and energy [2].Laminates are the main material processing and application forms,where the tubular bamboo internodes with unidirectionally arranged fibrous vascular bundles play key roles [1,2].

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Two Types of Liquid Phase Separation Induced by Soft centrifugation in Aqueous Ethyl Acetate Using Ethanol as cosolvent

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Research 2023年第3期6卷 451-460页

作者： helmut cölfen Rose Rosenberg Dirk Haffke Simon Stemplinger Thomas Zemb Dominik Horinek Physical chemistry Department of ChemistryUniversity of KonstanzUniversitätsstr.10D-78457 KonstanzGermany Institute for Separation chemistry IcSM U Montpellier/cEA/cNRS/ENScM MarcouleFrance Institute of Physical and Theoretical chemistry University of RegensburgD-93040 RegensburgGermany

Water/ethyl acetate/ethanol is widely used as a“green”extractant *** show that 2 different types of phase separation can be induced upon centrifugation in this ternary system using ethanol as a cosolvent of water and ethyl acetate:centrifuge-induced criticality and centrifuge-induced *** expected composition profiles of samples after centrifugation can be represented by bent lines in a ternary phase diagram when gravitational energy is added to the free energy of *** experimental equilibrium composition profiles behave qualitatively as expected and can be predicted using a phenomenological theory of *** concentration gradients are small except near the critical point,as expected for small ***,they are usable when accompanied by temperature *** findings open new possibilities of centrifugal separation,even if control is delicate during temperature *** schemes are accessible even at relatively low centrifugation speed for molecules that float and sediment with apparent molar masses several hundred times larger than the molecular mass.

关键词： separation ternary apparent

chirality communications between inorganic and organic compounds

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SmartMat 2021年第1期2卷 17-32页

作者： Bing Ni helmut cölfen Physical chemistry Department of ChemistryUniversity of KonstanzKonstanzGermany

1|INTRODUcTION chirality spans over almost every size range,from mole-cules to biological systems and even to *** is one of the fascinating geometrical properties with a lot of amazing manifestations in the material *** chemi-cal researchers,we are more interested in chirality at the molecular scale and *** molecules are found important in life science,agrochemicals,pharma-ceutical industries,biosensing,display materials,and so forth.1–5 chirality stems from a structure lacking sym-metry elements of inversion symmetry and mirror‐plane,which makes the structure not superimposable with its mirror *** these two kinds of symmetries,any structure is chiral,besides conventional chiral organics or spiral inorganic *** essence of chirality is the stereochemistry of molecules or nanostructures.

关键词： chiral inorganic mirror

Synthesis of hierarchical transition metal oxyhydroxides in aqueous solution at ambient temperature and their application as OER electrocatalysts

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Journal of Energy chemistry 2022年第8期31卷 89-97,I0003页

作者： Zongkun chen Xingkun Wang Sascha Keßler Qiqi Fan Minghua Huang helmut cölfen University of Konstanz Physical ChemistryUniversitätsstraße 10Konstanz D-78457Germany School of Materials Science and Engineering Ocean University of ChinaQingdao 266100ShandongChina

First-row(3 d)transition metal oxyhydroxides have attracted increasing attention due to their various *** investigating the oxidation mechanism and processing such materials into hierarchical architectures are greatly desired for their further development,it remains unclear how the oxidation state change occurs,and efforts to produce hierarchical oxyhydroxides in compliance with high ecological and economic standards have progressed ***,we describe a facile one-step coprecipitation route for the preparation of hierarchical coOOH,NiOOH and MnOOH,which involves the diffusion of NH_(3)originating from ammonium hydroxide solution into an aqueous solution containing metal ion salts and K_(2)S_(2)O_(8).comprehensive characterizations by scanning electron microscope,transmission electron microscopy,X-ray diffraction analysis,X-ray photoelectron spectroscopy,ultraviolet-visible spectroscopy and in situ p H measurement demonstrated that K_(2)S_(2)O_(8)induces the oxidation state change of metal ion species after the start of ***,it was found that,benefiting from the OH–concentration gradient created by the NH_(3)diffusion method and the suitable growth environment provided by the presence of K_(2)S_(2)O_(8)(high nucleation rate and secondary nucleation),the formation of hierarchical oxyhydroxide structures can be realized in aqueous solution at ambient temperature without the use of heat energy and additional structure-directing *** hierarchical coOOH structures are performed as the electrocatalysts for the oxygen evolution reaction in alkaline media,which exhibit good activity with an overpotential of 320 m V at 10 m A cm^(-2)and a low Tafel slope of 59.6 m V dec^(–1),outperforming many congeneric ***,our study not only provides important insights to understand the formation mechanism of hierarchical oxyhydroxides,but also opens up new opportunities for the preparation of hierarchical oxyhydroxides via a f

关键词： Formation mechanism Hierarchical transition metal oxyhydroxides Aqueous solution Ambient temperature Oxygen evolution reaction

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Bivalve hinge reveals the structural design of fatigue-resistant deformable ceramic materials

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Science china Materials 2023年

作者： helmut c?lfen Physical chemistry University of Konstanz Universit?tsstra?e 10

Sophisticated principles of design and material integration of biomaterials have long been a major source of inspiration for the development of artificial materials [1,2]. In recent years, inspired by the multi-level architecture of biomineral materials such as shell nacre [3,4], tooth enamel [5], and bone [6], several strong and tough bioinspired structural materials like advanced ceramic composites and metallic alloys have been reported. Therefore, the practice of learning from nature is continuing [7]. The development of artificial intelligence, flexible electronic wearables, and other fields has led to increasing demands for highperformance and fatigue-resistant functional flexible composite materials with inorganic nano-elements [8,9]. This poses the challenge to ensure that these deformable materials function consistently and stably over a long period of time.

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A Stellar Life

Research in Astronomy and Astrophysics 2022年第11期22卷 1-13页

作者： helmut A.Abt Kitt Peak National Observatory Box 26732TucsonAZUnited States of America

In this autobiography of 70+yr of publishing astronomical papers,I summarize some of my major fields of research,such as(1)hfs in the solar spectrum,(2)the atmospheres of supergiants,(3)shock waves in cepheids,(4)the crab Nebula,(5)frequencies of binaries,(6)exoplanets,(7)starting Kitt Peak National Observatory,(8)catalogs,(9)china,(10)editing the Astrophysical Journal,(11)blue stragglers,(12)the Local Interstellar Bubble,and(13)publication studies.

关键词： biographies stars:general ISM:supernova remnants

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