Mechanochemical reactions on poly(vynilchloride)

The creep of a rigid material based on poly(vinylchloride) modified with benzidine is studied under tensile stress conditions. Based on the proposed rheological model, the creep equation is derived. The modifications induced by the mechanical stress on some physical properties of the material are studied. The analysis of the facture surfaces shows a brittle character of the fracture, especially in the final stage of the process.     

Mechanochemischer Abbau bei der Schwingmahlung von Poly(8-caprolactam) in Gegewart von Sebacoyl-chlorid und nachfolgende Polykondesation mit aromatischen diaminen

Ohne Zusammenfassung     

Of possible cheminformatics futures

For over a decade, cheminformatics has contributed to a wide array of scientific tasks from analytical chemistry and biochemistry to pharmacology and drug discovery; and although its contributions to decision making are recognized, the challenge is how it would contribute to faster development of novel, better products. Here we address the future of cheminformatics with primary focus on innovation. Cheminformatics developers often need to choose between “mainstream” (i.e., accepted, expected) and novel, leading-edge tools, with an increasing trend for open science. Possible futures for cheminformatics include the worst case scenario (lack of funding, no creative usage), as well as the best case scenario (complete integration, from systems biology to virtual physiology). As “-omics” technologies advance, and computer hardware improves, compounds will no longer be profiled at the molecular level, but also in terms of genetic and clinical effects. Among potentially novel tools, we anticipate machine learning models based on free text processing, an increased performance in environmental cheminformatics, significant decision-making support, as well as the emergence of robot scientists conducting automated drug discovery research. Furthermore, cheminformatics is anticipated to expand the frontiers of knowledge and evolve in an open-ended, extensible manner, allowing us to explore multiple research scenarios in order to avoid epistemological “local information minimum trap”.     

Distant collaboration in drug discovery: the LINK3D project

The work describes the development of novel software supporting synchronous distant collaboration between scientists involved in drug discovery and development projects. The program allows to visualize and share data as well as to interact in real time using standard intranets and Internet resources. Direct visualization of 2D and 3D molecular structures is supported and original tools for facilitating remote discussion have been integrated. The software is multiplatform (MS-Windows, SGI-IRIX, Linux), allowing for a seamless integration of heterogeneous working environments. The project aims to support collaboration both within and between academic and industrial institutions. Since confidentiality is very important in some scenarios, special attention has been paid to security aspects. The article presents the research carried out to gather the requirements of collaborative software in the field of drug discovery and development and describes the features of the first fully functional prototype obtained. Real-world testing activities carried out on this prototype in order to guarantee its adequacy in diverse environments are also described and discussed.In addition to the mentioned institutions the LINK3D Consortium is constituted by     

Spectroellipsometric Characterization of Multilayer Sol-Gel Fe2O3 Films

Multilayer Fe₂O₃ films were deposited by the sol-gel method on glass substrates using three successive deposition procedures. The films were thermally treated for 1 h at 300°C.The optical and microstructural properties of these films were investigated by spectroscopic ellipsometry (SE) in the 500–1000 nm range. The optical gap was found by fitting the dispersion of the film refractive index (n) with the Wemple-DiDomenico (WDD) formula.The ellipsometric measurements showed also that the Fe₂O₃ films are anisotropic. The birefringence values (n) of the sol-gel films (0.05–0.08) are smaller than the large values of the Fe₂O₃ (which are around 0.28) but increase with the crystalization of the films. AFM mesurements showed that the films treated at 300°C start to crystallize.     

“神光”装置的激光能量测量

本文叙述了在神光装置中测量激光能量的体吸收能量计的特点,给出了其工作参数。实测了神光装置中激光系统末级输出能量、激光系统前部和中部定点发射能量及激光系统放大的自发辐射能量。并作了分析和讨论。     

Mechanochemical reactions on poly (vinyl chloride)

This paper is concerned with molecular phenomena appearing during deformation of poly(vinyl chloride) under tensile stress conditions. By using indirect techniques (reactions with radical acceptors, with vinylic monomers, electron microscopy) the formation of free radicals, appearing as a consequence of splitting of chemical bonds, is evidenced. The amount of reacted radical acceptor or monomer was proved to be related to solution concentration and to the duration of mechanical stress.     

Reactivity of acrylic monomers

Summary The copolymerization of N,N-diethylacrylamide (M_l) with methyl acrylate (M₂) was investigated and reactivity ratiosr ₁= 0.41 andr ₂ = 0.52 obtained. Also the distribution of diad fractions was calculated and the results were interpreted in terms of the product of reactivity ratios. The tendency of the two monomers to alternate was explained on the basis of differences in polatities between the double bonds, this explanation being supported both by the values ofe parameter and NMR spectroscopy data. A copolymerization mechanism was suggested.With 5 figures and 2 tables