From Top-Down to Bottom-Up to Hybrid Nanotechnologies: Road to Nanodevices

The current development and future prospects of nanotechnology are discussed with special emphasis on the pros and cons of the “bottom-up” and “top-down” approaches to nanotechnology, and the eventual merging of the two, at the scale of about 30 nm in feature size, to form a new “hybrid” technology. At the scale of about 3 nm in feature size, this “hybrid” technology will be challenged by the emerging “supramolecular” and “molecular” technologies epitomized by large-scale integration of single-molecule devices. Ultimately the “supramolecular” and “molecular” technologies will yield to “atomic” or “nuclear” technologies at the dimension of below 0.3 nm whereby single-atom, single-electron, single-spin, single-photon devices become realities.     

Adhesion to mineralized tissue: Bonding to human dentin

We consider the conditions and demonstrable reactions which promote chemical bonding to human dentin. The desirability of developing durable adhesion to dentin is used as background for a discussion of feasible reactions to the dentin components, for possible use in new formulations. This is followed by a discussion of the demonstrable reactions found in the literature, as well as our own surface-sensitive IR work on the reaction between dentin protein and 2-hydroxyethyl methacrylate, an ingredient found in proprietary tissue replacement formulations.     

从自然到仿生到实际应用的超亲水表面

极端润湿表面一直是表面工程领域的重要研究主题。由于与水具有强烈的吸引力,超亲水表面具有自清洁、防雾等特点,在很多领域都表现出很强的应用潜力。与超疏水表面相比,超亲水表面的研究相对较少,在学术和应用上还存在一些问题。本文介绍了关于超亲水定义的学术争论,分析了超亲水现象的机理,还介绍了超亲水表面的制备方法和实际应用,并指出了超亲水表面存在的问题和研究新动向。本文为超亲水表面的研究提供了一个较为全面/系统的综述。     

Borazine: to be or not to be aromatic

Aromaticity of borazine, which has been subject of controversial discussions, is addressed. Beside a short review on aromaticity of borazine we report a detailed analysis of two molecular fields, the induced magnetic field (B ^ind) and the electron localization function (ELF). The induced magnetic field of borazine shows a long-range shielding cone perpendicular to the molecular plane, as in benzene, but lower in magnitude. Contrary to benzene, borazine shows two weakly paratropic regions, one of them inside the ring, and the second one enveloping the boron atoms. It is necessary to separate σ and π contributions to identify whether borazine exhibits π-aromatic character comparable to benzene. Nucleus-independent chemical shift (NICS) isolines show that the σ electrons are much stronger localized than π electrons, their local paramagnetic contributions generate a short-range response and a paratropic (deshielding) region in the ring center (similar to an anti-aromatic response). Three regions can be identified as chemically meaningful domains exhibiting an internally strong electron delocalization (ELF = 0.823). Borazine may be described as a π aromatic compound, but it is not a globally aromatic species, as the electronic system is not as delocalized as in benzene. Dedicated to the 70th birthday of Prof. Tadeusz Marek Krygowski.     

Pyrones to pyrans: enantioselective radical additions to acyloxy pyrones

This paper describes a highly site-, diastereo-, and enantioselective intermolecular radical addition/hydrogen atom transfer to hydroxypyrone pyromeconic and kojic acids. The methodology can be extended to the formation of chiral quaternary centers. The products obtained are densely functionalized pyran moieties. The products contain structural features amenable for the introduction of additional substituents.     

石墨炔:从合成到应用

正石墨炔是一种新型碳的同素异形体,是由sp和sp~2两种杂化形式的碳原子组成的二维层状材料~1。具有中国自主知识产权的石墨炔自2010年被首次成功合成以来,吸引了全世界来自化学、物理、材料、生物和电子等学科的科学家对其进行探索~2。石墨炔独特的纳米级孔隙、二维层状共轭骨架结构及半导体性质等特性,使之在能源、电化     

Multi-Polymerization: From Simple to Complex

Multi-polymerization in which different polymerization mechanisms are performed together serves as an essential synthetic methodology for the construction of polymers with specific architectures, constitutions, and properties. Compared to single mechanism polymerization, the scope of multi-polymerization is significantly broadened by both the available synthetic methods and the synthesized polymeric materials. In this mini-review, multi-polymerizations are categorized into three major types base...