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  • 1
    Electronic Resource
    Electronic Resource
    Effects of reappearance of fixated and attended stimuli upon saccadic reaction time (1990)
    Springer
    Experimental brain research 81 (1990), S. 318-324 
    Details
    ISSN: 1432-1106
    Keywords: Attention ; Fixation ; Saccadic reaction time Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of visual attention and fixation upon the distribution of saccadic latencies: express (E-), fast regular (FR-), and slow regular (SR-) saccades were investigated. Extinguishing a fixation or an attention point 200–300 ms before target onset increases the incidence of E-saccades while concurrently decreasing the proportion of SR-saccades. Since this extinction forces a disengaging of attention, these changes in relative proportions of saccades reflect the elimination of one of the steps involved in programming saccades. It is shown that a previously attended stimulus has a favored status relative to other stimuli in the visual field. If, after being turned off, the previously attended fixation point or a peripheral attention stimulus is turned on near the time of the target's appearance, the occurrence of the E-saccades is greatly reduced. However, the appearance of any other stimulus in the visual field at or near the time of the target onset does not inhibit E-saccades. Contrary to the conclusions reached by Posner and Cohen (1984), a stimulus presented at the formerly attended location can attract attention more efficiently than a stimulus presented at another, new location.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228122
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  • 2
    Electronic Resource
    Electronic Resource
    Relationship between directed visual attention and saccadic reaction times (1988)
    Springer
    Experimental brain research 73 (1988), S. 546-552 
    Details
    ISSN: 1432-1106
    Keywords: Attention ; Fixation ; Saccades ; Saccadic reaction times
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Saslow (1967) and Fischer and Ramsperger (1984) found that saccadic reaction time (SRT) depends on the interval between the fixation point offset and the target onset. Using a continuously visible fixation point, we asked whether a similar function would be obtained if subjects attended to a peripherally viewed point extinguished at variable intervals before or after the target onset. The interval was varied between -500ms (i.e., attention stimulus offset after saccade target onset = overlap trials) and 500ms (i.e., attention stimulus offset before saccade target onset = gap trials). The results show a constant mean SRT of about 240 ms for overlap trials, and a U-shaped function with a minimum of 140 ms, at a gap duration of 200 ms, for gap trials. These findings suggest that saccadic latencies do not depend on the cessation of fixation per se, but rather on the disengagement of attention from any location in the visual field. The time required for subjects to disengage their attention is approximately 100 ms. This disengaged state of attention — during which short latency (express) saccades can be made — can be sustained only for a gap duration of 300 ms. At longer gap durations mean SRTs increase again.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406613
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  • 3
    Electronic Resource
    Electronic Resource
    Alternierende Copolymerisation von Styrol und Benzylmethacrylat in Gegenwart von Ethylaluminiumsesquichlorid (1982)
    Springer
    Colloid & polymer science 260 (1982), S. 995-998 
    Details
    ISSN: 1435-1536
    Keywords: Alternating Copolymerization ; Styrene ; Benzylmethacrylate ; Tacticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Abstract The alternating copolymerization of styrene and benzylmethacrylate shows a different behaviour at the beginning of the reaction and later on. Thus the composition and the intrinsic viscosity of the products as well as the reaction rate become constant only after the initial stage. The1H-NMR-spectra of alternating and statistical copolymers with equal composition show distinct differences. The spectrum of the alternating copolymer confirms the alternating structure as well as an atactic chain configuration.
    Notes: Zusammenfassung Die alternierende Copolymerisation von Styrol und Benzylmethacrylat in Gegenwart von Ethylaluminiumsesquichlorid als Katalysator zeigt im Anfangsstadium der Reaktion ein vom weiteren Verlauf abweichendes Verhalten. So nehmen die Zusammensetzung und die Grenzviskositäten der Produkte sowie die Reaktionsgeschwindigkeit erst nach der Anfangsphase konstante Werte an. Die1H-NMR-Spektren von alternierenden und statistischen Copolymeren gleicher Bruttozusammensetzung zeigen deutliche Unterschiede. Das Spektrum des alternierenden Copolymeren bestätigt die alternierende Struktur und spricht gleichzeitig für einen ataktischen Kettenaufbau.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01451645
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  • 4
    Electronic Resource
    Electronic Resource
    Lösungseigenschaften von äquimolaren statistischen und alternierenden Copolymeren aus Styrol und Benzylmethacrylat (1982)
    Springer
    Colloid & polymer science 260 (1982), S. 1011-1016 
    Details
    ISSN: 1435-1536
    Keywords: Copolymers ; Styrene ; Benzylmethacrylate ; Solution properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Abstract Solution properties of equimolar random and alternating copolymers of styrene and benzyl methacrylate were investigated by means of light scattering and viscosity measurements. The two copolymers showed no distinct difference between each other. A special stiffening effect of the aromatic ring of the benzyl methacrylate could not be found. Light scattering data showed a pronounced influence of the third virial coefficient and the conventional interpretation of the data (linear extrapolation toc=0) produced too high molecular weights.
    Notes: Zusammenfassung Die Lösungseigenschaften von äquimolaren statistischen und alternierenden Copolymeren aus Styrol und Benzylmethacrylat wurden mit Hilfe von Lichtstreuungs- und Viskositätsmessungen untersucht. Es ergaben sich keine gravierenden Unterschiede zwischen den beiden Copolymeren. Ein besonderer kettenversteifender Effekt des aromatischen Rings im Benzylmethacrylat konnte nicht nachgewiesen werden. Bei der Lichtstreuung zeigte sich ein deutlicher Einflu\ des dritten Virialkoeffizienten, wodurch die konventionelle Auswertung (lineare Extrapolation aufc=0) zu hohe Molekulargewichte lieferte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01451647
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  • 5
    Electronic Resource
    Electronic Resource
    Ozoninduzierter Abbau von Polyoxymethylen (1988)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 156 (1988), S. 123-137 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Samples of polyoxymethylene (unstabilized and stabilized with the antiozonants N-isopropyl-N′-phenyl-p-phenylenediamin (IPPD) and bis-(1,2,3,6-tetrahydrobenzaldehyd)pentaerithritylacetal (Vulkazon AFS)) were ozonized under mechanical load in a special climate chamber. Surface damages were determined by IR-spectroscopy and scanning electron microscopy. During the ozonolysis a damaged layer is formed, the thickness of which increases with increasing time of ozonization. During this damaging reaction acetal groups are attacked and oligomers are formed.
    Notes: Proben von unstabilisiertem und mit den Antiozonantien N-Isopropyl-N′-phenyl-p-phenylendiamin (IPPD) und Bis-(1,2,3,6-tetrahydrobenzaldehyd)-pentaerithrityl-acetal (Vulkazon AFS) stabilisiertem Polyoxymethylen wurden unter mechanischer Belastung in einer Klimakammer ozonisiert. Die Schädigungen auf der Oberfläche wurden IR-spektroskopisch und rasterelektronenmikroskopisch untersucht. Während der Ozonisierung von POM bildet sich eine geschädigte Schicht, deren Dicke mit zunehmender Ozonisierungszeit wächst. Hierbei wird das Polymere an den Acetalbindungen angegriffen, wodurch Ketten gespalten werden und Oligomere entstehen.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1988.051560111
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  • 6
    Electronic Resource
    Electronic Resource
    Strain-induced crystallisation and miscibility behaviour of hydrogenated nitrile rubbersPaper presented at the meeting of the GDCh-Fachgruppe “Makromolekulare Chemie” on “Kautschukelastische Polymersysteme” in Bad Nauheim (Germany), March 30-31, 1992. (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 202 (1992), S. 143-158 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: HNBR rubbers, which are made by selective hydrogenation of the olefinic bonds of NBR rubbers, have been developed, because they show improved resistance towards heat and chemicals. In this study, two other properties are discussed that arise from the fact that HNBR rubbers are fairly alternating copolymers of unpolar butylene and polar acrylonitrile units: At intermediate compostions, HNBR rubbers form homogeneous blends with PVC, and near the symmetric composition they exhibit strain-induced crystallisation. The thermal transitions of the HNBR rubbers and their miscibility with PVC were analyzed, as well as the crystallisation and the stress-strain behaviour of a HNBR of symmetric composition.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.052020109
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  • 7
    Electronic Resource
    Electronic Resource
    Mutual miscibility of chlorinated hydrocarbon polymers derived from polyethylene and polyvinylchlorideDedicated to Prof. Dr. Dr. h. c. H. Hellmann on the occasion of his 75th birthday (1989)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 171 (1989), S. 53-63 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Untersucht wurde die Verträglichkeit von polymeren Chlorkohlenwasserstoffen mit verschiedener Comonomersequenzordnung. Eine erste Copolymerenserie (“PVCx”) wurde durch Reduktion von Polyvinylchorid hergestellt, eine zweite Serie (“PECx”) durch Chlorieren von Polyethylen. Die Polymer-Legierungen PECx/PECy, PVCx/PVCy und PVCx/PECy wurden bei 30°C und 110°C mit einer Lösungsfilmmethode analysiert. Im System PECx/PECy nimmt die Mischbarkeit mit steigendem Chlorgehalt der Copolymeren stetig zu. Bei den Systemen PVCx/PVCy und PVCx/PECy zeigt sich im Bereich um x = 1 eine erhöhte Tendenz zur Phasenseparation, die auf die bessere Comonomersequenzordnung der Copolymeren PVCx zurückzuführen ist. Im letzteren System ist diese Tendenz so stark, daß Polyvinylchlorid (PVCx=1) sogar mit dem chlorierten Polyethylen PECx=1, das die gleiche Bruttozusammensetzung hat, nicht mischbar ist.
    Notes: The compatibility of chlorinated hydrocarbon polymers of two different comonomer sequence orders was investigated. One series of copolymers (“PVCx”) was prepared via reduction of polyvinylchloride, the other (“PECx”) via chlorination of polyethylene in solution. The blends PECx/PECy, PVCx/PVCy and PVCx/PECy were analyzed with a film casting method at 30°C and 110°C. Miscibility increases in the system PECx/PECy steadily in the direction of increasing chlorine content. Due to the comonomer sequence order in the copolymers PVCx the systems PVCx/PVCy and PVCx/PECy show in the range around x = 1 an extra effect favouring phase separation. In the latter system this effect is so strong that polyvinylchloride (PVCx = 1) is even incompatible with the chlorinated polyethylene PECx=1 although both have the same overall composition.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1989.051710104
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  • 8
    Electronic Resource
    Electronic Resource
    Polyesters with 1.4:3.6-dianhydrosorbitol as polymeric plasticizers for PVCDedicated to Professor Dr. W. Heitz on the accasion of his 60th birthday (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 199 (1992), S. 191-205 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Gesättigte aliphatische Polyester mit dem aus Stärke erhältlichen 1.4:3.6-Dianhydrosorbit wurden mit PVC gemischt. Die mechanischen Eigenschaften dieser Mischungen wurden mittels Differentialkalorimetrie, Spannungs-Dehnungs-Experimenten und Torsionspendelmessungen untersucht. Polyester mit mehr als vier Methylengruppen in der Säurekomponente sind mit PVC mischbar. Mischungen aus PVC und Poly(1.4:3.6-dianhydrosorbitadipat) sind dagegen unverträglich; sie zeigen für jedes Mischungsverhältnis zwei Glastemperaturen, die bei denen der Reinkomponenten liegen.
    Notes: Saturated aliphatic polyesters with 1.4:3.6-dianhydrosorbitol units were mixed with poly(vinylchloride) (PVC). The mechanical properties of these mixtures were examined by differential scanning calorimetry, stress-strain experiments, and torsion pendulum measurements. Polyesters containing more than four methylene groups in the acid component are compatible with PVC. These polyesters can serve as plasticizers for PVC. On the contrary, mixtures of PVC with poly(1.4:3.6-dianhydrosorbitol adipate) are incompatible; in this case, at any blend composition, the two glass transition temperatures of the pure components are observed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.051990115
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  • 9
    Electronic Resource
    Electronic Resource
    Grafting of polyesters by free-radical chain transfer (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 210 (1993), S. 173-196 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch radikalische Kettenübertragung ausgelöste Pfropfcopolymerisationen von Polyestern rnit Styrol wurden untersucht. Als Rückgratkette diente ein Modellpolyester aus trans- 1,4-Cyclohexandiol und Sebacinsäuredichlorid. Ferner wurden flüssigkristalline Polyester rnit 1,4 : 3,6-Dianhydrosorbit und 1,4-Anhydroerythrit als Diolkomponenten hergestellt und zur Pfropfcopolymerisation mit Styrol eingesetzt. Polymerblends aus Tetramethylbisphenol A-Polycarbonat und den ungepfropften sowie mit Styrol gepfropften flüssigkristallinen Polyestern wurden durch gemeinsame Fällung von Polymerlösungen erhalten; ihr Verhalten wurde mit Torsionspendelmessungen, dynamisch-mechanischer Thermoanalyse und Elektronenmikroskopie untersucht. Der gepfropfte Polyester erwies sich dabei als wirksamer Phasenvermittler.
    Notes: Graft copolymerizations of polyesters with styrene by free-radical chain transfer reactions were investigated. A model polyester of trans-l,4-cyclohexanediol and sebacoy1 dichloride was used as backbone chain. The graft products were characterized. Furthermore, liquid crystalline polyesters with 1,4 : 3,6-dianhydrosorbitol and 1,4-anhydroerythritol as diol components were synthesized and used in graft copolymerizations with styrene. Polymer blends of tetramethylbisphenol A polycarbonate and the LC-polyester with and without polystyrene grafts were prepared by common precipitation of polymer solutions and their behaviour was examined by torsion pendulum, dynamic-mechanical thermoanalysis and scanning electron microscopy. The grafted polyester turned out to be an efficient phase compatibilizer.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052100114
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  • 10
    Electronic Resource
    Electronic Resource
    Triazine-based polymers, 2. Synthesis and characterization of polyethers (1994)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 221 (1994), S. 187-205 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Polyether auf Triazinbasis können mittels phasentransferkatalysierter Polykondensation bei Raumtemperatur und Reaktionszeiten von 1 bis 3 h hergestellt werden. Von mehr als 20 Polyethern wurden Löslichkeiten, Glasübergangstemperaturen, thermogravimetrische Daten, Reißdehnungen, Reißfestigkeiten, Elastizitätsmoduli und Schlagzähigkeiten bestimmt. Von den Polymeren aus 2,4-Dichlor-6-diethylamino-s-triazin und Bisphenol A wurde zusätzlich der Kristallisationsgrad mittels Röntgenweitwinkelstreuung ermittelt. Das Inkrement des 1,3,5-Triazintriylrings wurde bestimmt, so daß die Glastemperaturen einiger Polyether nach van Krevelen berechnet werden konnten.
    Notes: Triazine-based polyethers can be synthesized by phase transfer catalysed interfacial polycondensation at room temperature and reaction times of about 1 to 3 h. In this way, more than 20 polyethers were synthesized and solubilities, glass transition temperatures, thermogravimetric data, elongations at break, tensil strengths, elasticity moduli and impact strengths were determined. In addition, the degree of crystallinity was investigated for the polymer obtained from of 2,4-dichloro-6-diethylamino-s-triazine and bisphenol A by wide angle X-ray diffraction. The increment of the 1,3,5-triazinetriyl ring was determined, which made it possible to calculate the glass transition temperatures of some polyethers according to van Krevelen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1994.052210116
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