Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-2234
    Keywords: Key words: Adaptive umbrella sampling ; Multicanonical sampling ; Helical peptide ; β-hairpin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract. Adaptive umbrella sampling of the potential energy is used as a search method to determine the structures and thermodynamics of peptides in solution. It leads to uniform sampling of the potential energy, so as to combine sampling of low-energy conformations that dominate the properties of the system at room temperature with sampling of high-energy conformations that are important for transitions between different minima. A modification of the procedure for updating the umbrella potential is introduced to increase the number of transitions between folded and unfolded conformations. The method does not depend on assumptions about the geometry of the native state. Two peptides with 12 and 13 residues, respectively, are studied using the CHARMM polar-hydrogen energy function and the analytical continuum solvent potential for treatment of solvation. In the original adaptive umbrella sampling simulations of the two peptides, two and six transitions occur between folded and unfolded conformations, respectively, over a simulation time of 10 ns. The modification increases the number of transitions to 6 and 12, respectively, in the same simulation time. The precision of estimates of the average effective energy of the system as a function of temperature and of the contributions to the average effective energy of folded conformations obtained with the adaptive methods is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 6 (1989), S. 81-85 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This Committee stood under the banner of joint meetings with the Crystallization Committee. Further it was characterized by two aspects, namely technological innovation in connection with measurement methods and their (on-line) application in engineering processes, whether for the sake of model formation or for process control or quality assurance in industry.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 1-7 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Describing the disperse state is important for quality assurance, operational safety and the design and modelling of processes, especially in solids technology. Starting materials, intermediates and end products have to be characterized. Apart from representative sampling, preparation greatly influences the results of particle characterization. Very fine particles are normally agglomerated unless a highly dispersed state is stabilized by an additive. For a meaningful measurement, they must be preserved in this state or be definitely dispersed, depending on the type of problem.If the point of interest is the present disperse state with regard to the processing characteristics, e.g. for a filtration, the system should not be changed by the preparation method. If it is necessary to determine the property functions, i. e. the functional relationship between technological and physical properties, it is necessary in general to use a high dispersion energy or a long dispersing time in order to obtain the best achievable dispersion. The finer and more unstable a disperse phase is, the more the correct processing is important for the result. The problems of dispersion in gases and liquids are discussed with some examples.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 4 (1987), S. 166-174 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Double pulse holography is, for experimental investigations, an extremely valuable means of measuring transport processes in disperse phases. This method allows the single or two dimensional frequency distributions of particle size, velocity, momentum and energy to be determined for each recorded sub-collective, with the additional possibility of checking the existence of their correlation. Being an imaging method, the distributions of the particles in space can be displayed along with the instantaneous values of the concentration and particle flux density.A complete and very exact evaluation of the holographic images, coupled with the certainty of image pairing, is one of the prerequisites of a successful application. The best evaluation in this sense is, at present, produced by a semi-automatic, interactive system in which the assessment of certain crucial factors is left to an operator.Although the effort incurred by such a total evaluation is by no means insignificant, it is justified by the profusion of information to be obtained.The present report explains the whole concept including a programme system with which the primary data is further processed and with which a variety of results may be called up and displayed.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 4 (1987), S. 1-6 
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A comprehensive description of gas-particle flows requires the knowledge of the distribution states of the particulate phase. To determine these distribution states in the first instance, optical methods are suitable, in particular double pulse holography. It yields a maximum amount of information, because as an imaging method it allows the determination of position, size and velocity of each individual particle of a collective simultaneously. The consequence is that the spatial distribution of the particles can be determined, as well as the frequency distributions of all the relevant quantities, such as diameter, velocity, momentum and energy as well as their local dependence and correlation. In the present case double pulse holography was employed to study different gas-particle flows at the outlet of a vertical tube (length 1 m, diameter 50 mm, mean gas velocity 3 m/s, Re = 10000). The dispersed phases consisted of water droplets with a broad size spectrum from 3 to 100 m̈m, and of glass spheres ranging from 20 to 35 μm.The most important results which are discussed in this paper are: 1the local dependence of concentration, mean size and mean particle velocity,2the frequency distributions of particle size and velocity,3the distributions of energy and momentum as function of particle size,4the correlation of particle velocity with particle size.The results reflect the different behaviour of the two particulate phases used.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 606 (1991), S. 73-78 
    ISSN: 0044-2313
    Keywords: Complexes of tetraselenium-dinitride ; syntheses ; IR-spectra ; 119Sn-Mössbauer spectrum ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Donor-Acceptor Complexes [SnCl4(Se4N2)2] and [TiCl4(Se4N2)]The donor-acceptor complexes [SnCl4(Se4N2)2] and [TiCl4(Se4N2)] have been prepared by the reactions of Se4N2 with SnCl4 and TiCl4, respectively, in CH2Cl2 suspensions, forming red-brown, moisture sensitive crystal powders. The complexes are characterized by i. r. spectroscopy, the tin compound additionally by 119Sn Mössbauer spectroscopy. According to the spectra, in the tin complex both Se4N2 molecules are bonded with one of the nitrogen atoms at the tin atom in transposition (symmetry Ci), whereas in the titanium complex we assume both nitrogen atoms to be bonded in a chelating fashion at the titanium atom.
    Notes: Die Donorakzeptorkomplexe [SnCl4(Se4N2)2] und [TiCl4(Se4N2)] werden aus den Komponenten Se4N2 und SnCl4 bzw. TiCl4 in CH2Cl2-Suspensionen in Form rotbrauner, feuchtigkeitsempfindlicher Kristallpulver hergestellt. Die Komplexe werden durch ihre IR-Spektren, die Zinnverbindung zusätzlich durch das 119Sn-Mößbauer-Spektrum charakterisiert. Danach sind die Se4N2-Moleküle in der Zinnverbindung in trans-Position über je ein N-Atom an das Zinnatom koordiniert (Symmetrie Ci), während in dem Titankomplex vermutlich beide N-Atome des Se4N2-Moleküls chelatartig an das Titanatom gebunden sind.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...