bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Solution Word Attributes on Anagram Difficulty: A Regression Analysis
Authors: Gilhooly K. J. , Johnson C. E.
Published: July 2007

A sample of 45 student subjects provided solution scores for 80 five-letter anagrams. These scores were analysed as a function of solution word imagery, con-creteness, familiarity, objective frequency, age-of-acquisition and associative meaningfulness using multiple regression techniques. Two bigram measures together with number of vowels, nature of starting letter (vowel or consonant), anagram pronounceability and anagram-solution similarity scores were also entered into the regression equations. The bigram measures, the starting letter and anagram-solution similarity emerged as having significant associations with the solution scores. Previous reports of imagery effects in anagram are discussed in the light of the present results.
Differential Runway Performance Using Goal Box Placement and Running Trials as Discriminative Stimuli
Authors: Seybert Jeffrey A. , Mays Mary Z. , Littlejohn Ray L. , Mellgren Roger L. , Haddad Nabil F.
Published: July 2007

Two experiments compared the effects of reinforced, partially reinforced and nonreinforced intertrial goal box placements (ITR, ITP, and ITN respectively) on runway performance. In Experiment I differential responding (animals running slower on nonreinforced (N) trials than on reinforced (R) trials) was observed during acquisition for subjects receiving ITP preceding N trials or subjects receiving ITP before R trials, and also for subjects receiving ITR preceding N trials. No differential responding was observed in subjects receiving ITP prior to both N and R trials or ITN prior to N trials. In extinction, the subjects which had responded differentially during acquisition demonstrated reduced resistance to extinction in comparison to the subjects which had not. In Experiment II, a 2 × 2 factorial design was utilized with placement schedule (ITN and ITP) and type of trial predicted by placement (N and R) serving as the factors. Differential responding was observed in all four groups. The apparent contradiction between the results and the discrimination hypothesis proposed by Capaldi and Olivier (1967) to explain the attenuation of ITR and ITN effects on resistance to extinction is discussed.
Apparatus Note: Conducting Experiments with Pencils
Authors: Monk Andrew , Spaven Don , Thomson Neil
Published: July 2007

Apparatus to close a circuit when a subject writes can be assembled using an ordinary wooden pencil and baking foil. Problems encountered in the construction of similar systems using internal contacts are thus avoided.
Rats' Sensitivity to Their Direction of Movement and Spontaneous Alternation Behaviour
Authors: Sherrick Michael F. , Brunner Robert L. , Roth Thomas G. , Dember William N.
Published: July 2007

The response of rats to their prior direction of movement was examined in three spontaneous alternation experiments. In the first, a straight alley run interpolated between two T-maze trials increased goal arm alternation when it was in the same direction as that of the animal's first T-maze goal arm entry and decreased the alternation tendency when it was in the opposite direction. Experiment II found that multiple runs in one direction in a straight alley increased the likelihood that rats would subsequently enter the goal arm of a T-maze which permitted movement in an opposite direction. In the third experiment, rats entered those goal arms of an eight-arm radial maze which permitted movement in any direction which was different from that during a preceding straight alley trial. The results of these experiments indicate that rats are quite sensitive to their direction of movement and use it as a cue in guiding their behaviour in a variety of experimental situations.
Learning and Reminiscence as a Function of Target Predictability in a Two-Dimensional Tracking Task
Authors: Frith Christopher D. , Lang Rudie J.
Published: July 2007

Twenty subjects performed one of two types of a two-dimensional tracking task for two 5-min sessions, separated by a 10-min rest. In task I, both the horizontal and the vertical components of target movement were unpredictable. In task II, the horizontal component of target movement was predictable (sinusoidal), while the vertical movement was unpredictable. There was no change in level of performance throughout the 10 min of practice on task I. For task II's predictable component, there were marked within- and between-session improvements in performance; whereas for the unpredictable component there was only a between-session improvement. It is proposed that, in these tracking tasks, improvement with practice depends on the development of programmed sequences of movement which can only occur for predictable target movements. Only after a rest do these programmed sequences become automatic, releasing spare attentional capacity for improving the performance of any unpredictable components of the task.
Information Processing by Performers and Observers in a Paired Associate Learning Task
Authors: Eelen Paul , D'Ydewalle Géry
Published: July 2007

The effects of two training procedures on learning and performance are compared. Performers select a response alternative for each stimulus on Trial 1 and receive feedback in terms of “Right” or “Wrong”. Observers receive the same information by listening to the experimenter. Experiment I tests the hypothesis that performers and observers are using a different learning strategy when there are only two response alternatives available for each stimulus on Trial 1. A recognition procedure was used on Trial 2; each stimulus was followed by four alternatives, two of them being the same as presented on Trial 1. Subjects have to recognize the two “old” alternatives. Performers are always better at recognizing the chosen alternative, whereas observers are better at recognizing the correct alternative. Experiment II extends the comparison between performers and observers to a task with four response alternatives on Trial 1. There are no longer differences in performance between the two training procedures.
Perception of Numerical Stimuli Felt by Fingers of the Left and Right Hands
Authors: Young Andrew W. , Ellis Andrew W.
Published: July 2007

Three experiments are reported in which blindfolded right-handed adults felt numerical stimuli with the middle fingers of their left or right hands. These stimuli consisted of collections of raised dots in random arrangement to be enumerated (Experiment I), collections of evenly spaced raised dots in a straight line to be enumerated (Experiment II), and raised digits to be identified (Experiment III). Differences between hands were only found in Experiment I. The left hand was faster, apparently reflecting specialisation of the right cerebral hemisphere for the analysis of complex spatial stimuli. A fourth experiment, in which collections of raised dots in random arrangement to be enumerated were felt through a piece of cloth by subjects who were not blindfolded, confirmed the left hand superiority and demonstrated that it had not arisen from loss of sight of the movements of the dominant hand.
Perceiving Surprising Words in an Unattended Auditory Channel
Authors: Yates Jack , Thul Nancy
Published: July 2007

This study addresses two related issues, the degree to which unattended auditory material is interpreted, and the processes by which the direction of attention is controlled. Subjects shadowed a prose passage presented to the right ear while an irrelevant list of names was presented to the left ear. At three points the list of names underwent an abrupt semantic change. When shadowing was stopped and the subjects were asked to recall left-channel material, recall was significantly better after changes than after control material not involving a change. There was a corresponding increase in shadowing errors at each locus of change. These results indicate that unattended material is processed to the semantic level and that change is among the factors which control the deployment of attention.
Modulation of Selective Attention by Sequential Effects in Visual Search Tasks
Authors: Rabbitt Patrick , Cumming Geoffrey , Vyas Subhash
Published: July 2007

In visual search detection of a target on one display facilitates its subsequent recognition on the next (Rabbitt, Cumming and Vyas, 1977). Experiment I shows that facilitation also occurs when a different display intervenes between two displays containing targets. Two further experiments show that detection of target letters among background letters is also facilitated if the same background letters recur on successive displays. Facilitation is greatest if background letters reappear in identical left-to-right spatial locations, but is also evident when the same background letters recur in different locations on successive displays. The results suggest modifications to models for the ways in which selective attention is continuously modulated by successive events during serial search.
Lexical and Grammatical Processing of Unshadowed Messages: A Re-Examination of the Mackay Effect
Authors: Newstead Stephen E. , Dennis Ian
Published: July 2007

Mackay (1973) claimed to have provided evidence that subjects could process the grammatical structure and lexical content of nonshadowed messages. In the present study, it was found impossible to repeat Mackay's findings when controls for several factors that had been ignored in Mackay's study were employed. Subsequent experiments indicated that two major factors contributing to Mackay's results were that he had a gap between sentences in his experiment and that the nonshadowed material came out of a background of silence. Both of these probably enabled subjects to switch attention to the nonshadowed material without disruption of shadowing performance.
Solving Anagrams: Category Priming and the Differential Availability of Category Solutions
Authors: Schuberth Richard E. , Spoehr Kathryn T. , Haertel Robert J.
Published: July 2007

An experiment was performed to test the hypothesis that the effect of category name priming on anagram solving varies with the strength of the relationship between the solution word and the priming category. Subjects solved anagrams of taxonomic category instances under primed or unprimed conditions. In the primed condition, the name of the taxonomic category from which the solution word was chosen was provided on each trial. Priming was shown to facilitate anagram solution and the extent of this facilitation was directly related to the instance dominance of the solution word in the priming category. The results were discussed in terms of current models of semantic memory.
The Effects of Smoking and Urinary pH on a Detection Task
Authors: Taylor Donald H. , Blezard Paul N.
Published: July 2007

Performance was measured in a detection task over a period of 50 min. Subjects were either non-smokers or smoked more than 15 cigarettes per day. No smoking was allowed during the task, but smokers were all asked to smoke a cigarette immediately before doing it. One hour previously, subjects had been given a double-blind dose of a substance which would shift the pH of their urine either upwards or downwards, by small amounts sufficient to affect the rate of renal excretion of nicotine in the smokers. The pH manipulation had no effect on the performance of the non-smokers, who improved steadily throughout the task. After some 40 min of performance, the deprived smokers showed less improvement than the non-smokers, and the smokers whose urine had been made acid improved less than those whose had been made alkaline. The results are interpreted as evidence for a phasic effect on performance of small degrees of nicotine deprivation, which has consequences for theories of nicotine dependence.
Exteroceptive Context in Tasteaversion Conditioning and Extinction: Odour, Cage, and Bottle Stimuli
Authors: Archer Trevor , Sjödén Per-Olow , Nilsson Lars-Göran , Carter Ned
Published: July 2007

Five experiments investigated the extent to which the exteroceptive context, present on a saccharin aversion conditioning trial with rats, controlled the resulting aversion on one-bottle extinction tests and subsequent preference tests. The presence or absence of the specific odour which had been present on the conditioning trial was found not to influence saccharin intake on extinction tests, whereas the presence of the particular compartment in which, and the bottle from which, the saccharin had been consumed greatly suppressed saccharin intake as compared to the absence of these elements. Preference tests, performed in the respective conditioning contexts, showed extinction to be specific to the compartment + bottle context: groups that had extinguished their saccharin aversion in a context different from the conditioning context, retained their aversion in the conditioning context. No such specificity was found for the odour context. However, in the absence of the taste stimulus during the extinction phase, the odour that had been present on the conditioning trial did control the amount of water consumed, whereas the compartment+bottle context did not. Moreover, on preference tests, groups that had consumed water during extinction in the presence of the odour context, evidenced a lesser saccharin aversion than groups not exposed to the odour. The results are interpreted as demonstrating that rats learn about taste, odour, cage and bottle stimuli on a taste-aversion conditioning trial, and that taste and bottle stimuli seem to be the most salient.
Selective Masking and the “Lamp-Phosphor” Problem
Authors: Merikle Philip M.
Published: July 2007

Mollon and Polden (1978) have suggested that selective backward masking, the greater masking of central than peripheral items in briefly-presented letter rows by a patterned stimulus, may be due to an advantage conveyed to the peripheral items by the more rapid onset of the short wavelengths emitted by tachistoscope lamps. This suggestion was evaluated by comparing report accuracy under mask and no mask conditions when the tachistoscope fields were viewed through yellow or red filters that eliminated all wavelengths below 510 and 590 nm, respectively. The results showed similar selective-masking effects with both filters. Since selective masking occurs even when the short wavelength emissions are eliminated, Mollon and Polden's suggested explanation for selective masking must be rejected.
The Effects of Helplessness Manipulations on Perceptual Responding: A Signal Detection Theory Analysis
Authors: Bekerian D. A.
Published: July 2007

This study was concerned with examining the effects of helplessness pre-treatment on performance in a perceptual task. Predictions from two different classes of helplessness hypothesis were considered. Cognitive hypotheses, such as the learned helplessness theory (Abramson, Seligman and Teasdale, 1978; Alloy and Seligman, 1979) suggest that the locus of helplessness effects is found in biases of perceptual and/or expectational mechanisms involved in analysing response-outcome events. These concepts were related to signal detection theory (SDT) and the predictions were that d’ and/or beta would vary as a function of helplessness exposure. In contrast, noncognitive hypotheses (Costello, 1978; Roth, 1975) do not predict that any differences would be reflected in either parameter. They merely stipulate that response factors are influenced by helplessness pre-treatment and do not require that any cognitive mechanisms be involved in producing the effects. Performance on a post-treatment orientation task was assessed using a SDT analysis following different helplessness pre-treatment. The analyses showed that neither d’ nor beta were affected by helplessness pre-treatment in the orientation task, even though the helplessness pre-treatment induced typical helplessness deficits in a parallel study using anagram solving as the post-treatment task. The only significant effects on the perceptual task were found in analyses of reaction times, with helpless individuals having faster responses. The results were most compatible with hypotheses suggesting that induced helplessness effects are the result of increasing levels of anxiety or arousal which affect performance factors such as responding time.
The Influence of Logic on Conditional Reasoning Performance
Authors: Pollard P. , Evans J. St. B. T.
Published: July 2007

Two experiments are reported, in each of which subjects were asked to decide whether or not a number of statements, including the inverse, converse and contra-positive, followed logically from a given conditional rule of the form “if P then Q”. Rules referred to letter, number relationships, the linguistic form being manipulated by systematic negation of the antecedent and consequent components.

The influence of logical validity on responses was investigated by examining differential frequencies with which inferences were drawn and by testing for consistent behaviour across inferences which depend upon the same logical principle. These analyses revealed little evidence for an influence of logic. Responses were found to be substantially influenced by a response bias, such that subjects showed a preference for agreeing with statements having affirmative antecedents and negative consequents. This finding was in part a replication of parallel findings on other inference tasks. In addition, correlational evidence suggested that subjects’ susceptibility to these biases was consistent across problems.

A possible explanation of the non-logical biases, in terms of a “caution” effect, was proposed and it was argued that these, and other, findings indicate that logical validity plays little role in mediating behaviour regarding the consequent of a conditional rule.
Social Informatics: A New Perspective on Social Research about Information and Communication Technologies
Authors: Kling Rob
Published: July 2007

Social informatics is the body of research that examines the design, uses and consequences of information and communication technologies in ways that take into account their interaction with institutional and cultural contexts. This article draws upon some 25 years of systematic, analytical and critical research about information and communication technologies (ICTs) and social change to illustrate key ideas from social informatics research.
Summit Diplomacy: High-Level Meeting or Courtesy Call? A Response to John Young
Authors: Dunn David Hastings
Published: July 2007

This essay is written in response to John Young's article in issue 1:3 of this journal, 'A Case Study in Summitry: The Experience of Britain's Edward Heath, 1979-1974', which chronicles the period's face-to-face meetings between heads of government. In his analysis, Young uses the definition of summitry that I set out in my 1996 book Diplomacy at the Highest Level: The Evolution of International Summitry. And yet in applying this definition of summitry as he does, he demonstrates the limitations of both this definition and indeed this approach to the study of diplomatic history in general.This article presents a critique of Young's use of summitry as a tool for understanding the diplomacy of the Heath administration in particular and diplomatic studies in general. It argues that the use of summitry in this way is a distorting lens through which to approach such an analysis. The article argues that Young's approach both overprivileges actual meetings as opposed to other executive involvement in diplomacy and downplays more significant activities, which fall outside this definition. If casual courtesy visits are to be included as summits, there is clearly something wrong with the definition being used. If this definition were to stand, then the term 'summit' and the use of summitry as a device for understanding diplomatic activity would be rendered meaningless. The article ends by suggesting new ways of defining summitry and pointing to the need for new research in this area.
Identification, Assessment, and Intervention Strategies for Deaf and Hard of Hearing Students With Learning Disabilities
Authors: Soukup Monica , Feinstein Sheryl
Published: July 2007

The purpose of the study was to ascertain methods of identification used by teachers of the deaf and hard of hearing who were working with students with learning disabilities, the training these teachers had received, and the accommodations and modifications they had implemented for their students. A 10-item survey was designed to solicit opinions and implementation procedures. Surveys went to teachers in a four-state region of the Midwest; 91 responded. Teachers indicated the use of various criteria to identify deaf and hard of hearing students with learning disabilities, and indicted that they incorporated a variety of accommodations to meet these students' needs. The survey showed that 50% of respondents did not feel adequately prepared to teach deaf and hard of hearing students with learning disabilities. Teachers expressed a desire for more training in identification, assessment, and intervention.
"Not Knowing What I Should Think:" The Landscape of Postmemory in W. G. Sebald's The Emigrants
Authors: Baumgarten Murray
Published: July 2007

In W.G. Sebald's The Emigrants the oblique relationship between narrative and image \-\- despite their interplay they are not synthesized – is associated with the workings of postmemory. In the fourth section of the novel the pictures of a German Jewish family that has emigrated to England and whose experience of the holocaust the narrator seeks to reconstruct are juxtaposed to the landscape which represses that history, generating a reiteration of that repression. The haunting presence of the images is paralleled by the paintings of a descendant of this family. The painter intentionally creates pentimento effects in his work: layers of paint hide and reveal the layers below. The methods of both painter and narrator involve a demonstration of the continued presence of loss. And when the narrator finally reaches the Lanzburg family gravesite he finds three empty gravestones and the only occupied grave, that of the painter's mother who committed suicide. This becomes the thematic center of the novel whose narrator is left "no knowing what he should think." His inability to turn self-reflection into resolution is contrasted with a Turkish woman's observation of Germany that the country is characterized by a refusal to reflect. The experience of disturbed self-reflection extends to the reader who must not only bear witness to the inconclusiveness of the narrator's discourse but take part in it, thus revealing the traces of the destruction and murder that the landscape through which he is traveling has tried to erase.
Paraoxonase and platelet-activating factor acetylhydrolase activities in lipoproteins of β-thalassemia/hemoglobin E patients
Authors: Phumala Morales Noppawan , Cherlermchoung Chalermkhwan , Fucharoen Suthat , Chantharaksri Udom
Published: July 2007

Clin Chem Lab Med 2007;45:884–9.
Unified model of necking and shear banding in amorphous and semicrystalline polymers
Authors: Sweeney J. , Caton‐Rose P. , Spares R. , Coates P. D.
Published: July 2007

In tensile stretching, many polymers undergo strain localization. The geometrical form of the localization can take the form of either a shear band or an approximately symmetric neck. We present a constitutive model of the early stages of deformation that predicts which form the localization will take. The model consists of an Eyring process acting with a Gaussian network that is implemented numerically. A Levy–Mises flow rule associated with the Eyring process has a tendency to produce shear bands. A relatively stiff Gaussian network is used in a model of polycarbonate that ensures that most of the strain is taken up by the Eyring process, resulting in shear banding. In contrast, a relatively soft Gaussian network is used in a model of polyethylene, which takes up the greater part of the strain, resulting in a neck. The predictions are compared with experiments. For polyethylene, a two‐Eyring‐process model is introduced for better accuracy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Novel technique for crosslinking and reinforcing high‐cis polybutadiene rubber using a silanized silica nanofiller
Authors: Ansarifar A. , Wang L. , Ellis R. J. , Haile‐Meskel Y.
Published: July 2007

A large amount of a precipitated amorphous white silica nanofiller was mixed with a high‐cis polybutadiene rubber. The silica surfaces were pretreated with bis(3‐triethoxysilylpropyl)tetrasulfide (TESPT). TESPT is a sulfur‐containing bifunctional organosilane that chemically adheres silica to rubber. The rubber was cured primarily with sulfur in TESPT, and the cure was optimized by the addition of a sulfenamide accelerator, which helped to form sulfur chemical bonds between the rubber and the filler. The hardness, tensile properties, tear strength, abrasion resistance, modulus, and cyclic fatigue life of the cured rubber improved substantially when the filler was added. Interestingly, this new technique produced a rubber with good mechanical properties, and only one accelerator was needed to optimize the chemical bonding between the rubber and the filler and fully cure the rubber. As a result, a substantial reduction in the use of the curing chemicals was achieved. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Preparation of antimicrobial poly(ϵ‐caprolactone) electrospun nanofibers containing silver‐loaded zirconium phosphate nanoparticles
Authors: Duan Yuan‐yuan , Jia Jun , Wang Shao‐hai , Yan Wei , Jin Lei , Wang Zhong‐yi
Published: July 2007

Antimicrobial nanofibers of poly(ϵ‐caprolactone) (PCL) were prepared by electrospinning of a PCL solution with small amounts of silver‐loaded zirconium phosphate nanoparticles (nanoAgZ) for potential use in wound dressing applications. The electrospun nanoAgZ‐containing PCL nanofibers were characterized using field emission scanning electron microscopy, energy dispersive X‐ray spectrum (EDX), X‐ray diffraction analysis (XRD), antimicrobial tests, and biocompatibility tests. The SEM, EDX, and XRD investigations of the electrospun fibers confirmed that silver‐containing nanoparticles were incorporated and well dispersed in smooth and beadless PCL nanofibers. The results of the antimicrobial tests showed that these fibers have maintained the strong killing abilities of Ag+ existed in the nanoAgZ against the tested bacteria strains and discoloration has not been observed for the nanofibers. To test the biocompatibility of nanofibers as potential wound dressings, primary human dermal fibroblasts (HDFs) were cultured on the nanofibrous mats. The cultured cells were evaluated in terms of cell proliferation and morphology. The results indicated that the cells attached and proliferated as continuous layers on the nanoAgZ‐containing nanofibers and maintained the healthy morphology of HDFs. The earlier results suggested that nanoAgZ‐containing fibers may be expected to be a novel material for potential wound dressing applications because of the significant bacteriostatic activities and good biocompatibility. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
[Russian Text Ignored]
Authors: Borščevski A. S. , Gorjunova N. A. , Kaljužnaja G. A. , Smirnova A. D. , Tachtareva N. K.
Published: July 2007

[Russian Text Ignored].
Der Einfluß von Kaliumfluoridschmelzen auf die chemische Zusammensetzung von BaTiO3‐Einkristallen
Authors: Arend H. , Novák J.
Published: July 2007

Der Einfluß von Kaliumfluorid als Lösungsmittel bei der Darstellung von BaTiO3‐Einkristallen auf ihre chemische Zusammensetzung wurde untersucht. Es wurde festgestellt, daß in das Kristallgitter ein kleiner Anteil von K‐ und F‐Ionen eingebaut wird. Weiterhin gelangen aus dem verwendeten Lösungsmittel kleinere Fe‐ und Pt‐Mengen in die Kristalle.
Erfahrungen bei der Züchtung von Eisen‐Yttrium‐Granat‐Einkristallen. Vortrag, gehalten auf dem Symposium „Kristallisation aus Schmelzlösungen”︁, 15.–17. 3. 1965 in Berlin
Authors: Kvapil Josef
Published: July 2007

In der vorliegenden Abhandlung werden die Erfahrungen zusammengefaßt, die bei der Züchtung von Eisen‐Yttrium‐Granateinkristallen gesammelt wurden. Es werden die Technik und die benutzten Schmelzen PbO, PbO+B2O3, PbO+PbF2 beschrieben. Für die günstigste Schmelze (PbO+PbF2) wurde eine Überschlagsrechnung der Temperaturerniedrigung während der Züchtung ausgeführt, die eine gleichmäßige, lineare Geschwindigkeit zuläßt. Die Ergebnisse für die gegebenen Züchtungsbedingungen sind in einem Nomogramm dargestellt.
Die Synthese faseriger Silikate unter thermischen Bedingungen
Authors: Fedoseev A. D. , Grigor'eva L. F. , Čigareva O. G.
Published: July 2007

Fluoramphibole der Richterit‐, Tremolit‐ und Arfvedsonitreihe sowie vom Holmquistit‐Typ wurden durch Kristallisation aus Schmelzlösungen synthetisiert. Der Einfluß der Zusammensetzung des Ausgangsmaterials, des Fluorgehaltes der Beschickung, der Erhitzungsdauer und der Abkühlungsgeschwindigkeit auf den Phasenbestand der Syntheseprodukte und auf Ausbildung und Habitus der entstehenden Amphibolkristalle wurde untersucht. Die optimalen Bedingungen für die Herstellung langfaseriger Amphibolkristalle werden mitgeteilt. Aus den Versuchsergebnissen werden Schlußfolgerungen auf den Mechanismus der Kristallisation der Fluoramphibole gezogen.
Der Einfluß der Zirkulation auf die Geschwindigkeit der Saccharose‐Kristallisation
Authors: Zagrodzki S. , Marczýnski J.
Published: July 2007

Die Kristallisation der Saccharose wurde in Lösungen verschiedener Reinheit und konstanter Übersättigung (1,15) bei verschiedenen Umdrehungsgeschwindigkeiten der kristallisierenden Lösungen untersucht. Die Experimente wurden in Thermostaten bei 65 °C ausgeführt.

Mit zunehmender Umdrehungsgeschwindigkeit der Kristallisiergefäße nahm die Menge der kristallisierten Saccharose zu.

Die Beziehungen zwischen den Umdrehungsgeschwindigkeiten und den Kristallisationsgeschwindigkeiten in Lösungen unterschiedlichen Reinheitsgrades werden mitgeteilt.
Wechselwirkungen zwischen Kristallmorphologie und permanenten Störungen während des Wachstums von Kristallen
Authors: Gülzow Hj.
Published: July 2007

Tracht und Habitus der Kristalle unterliegen während des Wachstums weitgehend dem Einfluß des Milieus, jedoch müssen unterschiedliche morphologische Entwicklungen nicht ausschließlich eine Folge veränderter Umweltfaktoren sein. In vielen Fällen ist als eine der wesentlichsten Ursachen für Abweichungen im morphologischen Verhalten die Existenz innerer gerichteter Störungen anzunehmen. In der vorliegenden Arbeit wird nachgewiesen, daß die Kausalität von Kristallstörungen und erhöhter Wachstumsgeschwindigkeit als ein Grund für die Entstehung von Kristallverzerrungen zu betrachten ist. Die unter dem Einfluß der Störungen vollzogene Habitusänderung führt dazu, daß die Störungen im Kristall zugunsten weniger gestörter Gebiete eliminiert werden können. An Hand einiger Beispiele natürlicher und künstlicher Kristalle wird die Rolle der Flächenkombination für den Bestand der Störungen nachgewiesen, soweit diese Störungen im Anfangsstadium des Wachstums entstanden sind. Für die Züchtung künstlicher Kristalle ergeben sich hieraus grundsätzliche Schlußfolgerungen.
Untergruppen der Raumgruppen
Authors: Neubüser Joachim , Wondratschek Hans
Published: July 2007

Die Gruppe—Untergruppen‐Relationen zwischen Raumgruppen sind bisher erst teilweise bekannt. In dieser Arbeit wird über Untersuchungen zu diesem Thema berichtet. Zur Ableitung der Untergruppen einer Raumgruppe und zur besseren Übersicht ist die Unterscheidung verschiedener Typen zweckmäßig. Es werden Wege besprochen, auf denen diese Ableitung von Untergruppen mit Rechenmaschinen oder von Hand relativ einfach möglich ist.

Die an anderer Stelle in Tabellen und Diagrammen erfaßten Gruppe—Untergruppe‐Relationen werden an Beispielen diskutiert. Anwendungen auf einige Fragen der Strukturkristallographie zeigen die Nützlichkeit der gewonnenen Beziehungen auch für andere Gebiete der Kristallographie.
Untersuchungen über die Tribolumineszenz in Abhängigkeit von den Zerkleinerungsvorgängen
Authors: Kürten H. , Rumpf H.
Published: July 2007

An Einzelteilchen aus Mangan‐aktiviertem Zinksulfid wird zunächst nachgewiesen, daß die Lichtemission an einen Zerkleinerungsvorgang gebunden ist. Die Leuchtdauer stimmt bei vielen Stoffen mit der Zeit überein, in der die Zerkleinerungsvorgänge ablaufen. Bei einer Prall‐ oder Druckzerkleinerung tribolumineszierender Stoffe beobachtet man so Lichtimpulse, die sich durch eine Integration über viele primäre Lichtblitze mit einer Zeitdauer von 2 – 7 · 10−8 s ergeben. Bei einer Kollektivzerkleinerung von ZnS:Mn und Zucker ist die emittierte Lichtmenge der neugeschaffenen Oberfläche proportional.
Beobachtung von Strömungen bei der Züchtung von Einkristallen aus Lösungen
Authors: Mýl J. , Šolc Z.
Published: July 2007

Es wurde eine neue Methode zur Beobachtung von Flüssigkeitsströmungen ausgearbeitet, bei der die Lumineszenz von reinen Anthrazenteilchen im UV‐Licht ausgenützt wird. Die Lichtspuren der Suspension dieser Teilchen beim Rühren in einem Kristallisator werden photographisch aufgenommen. Aus der Länge der Lichtspuren wird die Strömungsgeschwindigkeit ermittelt.

Diese Methode wurde zur Beobachtung von Strömungen in einem Kristallisator der üblichen Konstruktion angewendet. Es zeigt sich, daß die relative Geschwindigkeit des Kristalls gegenüber der Mutterlösung nicht nur durch die Rotationsgeschwindigkeit, sondern auch von anderen Faktoren bestimmt wird. Einen großen Einfluß darauf hat der Durchmesser des wachsenden Kristalls, so daß die Strömung im Kristallisator während der Kristallzüchtung ihren Charakter verändert.

Die Bedingungen der Züchtung bei konstanten hydrodynamischen Verhältnissen werden erörtert.
Einige Gedanken über die Entwicklung und den Einsatz künstlicher Kristalle
Authors: Görlich P. , Karras H. , Lüdke W.
Published: July 2007

Es wird ein Überblick gegeben über die Entwicklung der Herstellung synthetischer Einkristalle im VEB Carl Zeiss Jena sowie über Bedeutung und Perspektive ihrer Anwendung.
Influence of Growth Conditions and Thermal History on the Constitution of NaNO3 Single Crystals
Authors: Eckstein J. , Perřinová M. , Rubinová E. , Urusovskaja A. A.
Published: July 2007

NaNO3 single crystals are prepared from melt by the method of lowering crucible using epitaxial growth of NaNO3 on mica. The suitable heat treatment preventing the cracking of single crystals is found, and the distribution of dislocations in annealed crystals has been studied. It is shown that the growth conditions have great influence on the perfection of crystals. The quality of crystals grown from melt can be improved so that it equals the quality of crystals grown from solution by preventing the melt from thermal decomposition of NaNO3 into NaNO2 by growing the crystals under oxygen pressure.
Bestimmung der optimalen Erstarrungsbedingungen bei der Einkristallzüchtung von Aluminium‐Zink‐Legierungen
Authors: Šíma V. , Jankovská L.
Published: July 2007

Bei der Einkristallzüchtung von Aluminium‐Zink‐Legierungen (Zingkehalt bis zu 30 Gew.‐%) nach der Bridgman‐Methode lassen sich aus den errechneten Erstarrungsbedingungen zur Verhinderung der Konzentrationsunterkühlung auch die Angaben für die Herstellung relativ homogener Einkristalle entnehmen.
Strukturdefekte in stark mit Antimon dotierten Siliziumeinkristallen
Authors: Mohr U.
Published: July 2007

Es wird über Untersuchungen berichtet, die an stark mit Antimon dotierten Si‐Kristallen durchgeführt wurden. Die Baufehler wurden mit Hilfe der röntgenographischen Lang‐Technik und der UR‐Mikroskopie identifiziert. Das Ausscheidungsverhalten des Antimons wurde ermittelt. Es wurden folgende Erscheinungsformen festgestellt:

Ausgedehnte Einzelausscheidungen an Versetzungen, die in geringer Dichte vor‐handen sind.

Vielzahl von kleinen Einzelausscheidungen an Versetzungen, die in geringer Dichte vorhanden sind.

Einzelne „punktförmige”︁ Ausscheidungen innerhalb cines dichten Netzes meist gekrümmt verlaufender Versetzungslinien.

Im wesentlichen durch gerade, parallel [110] verlaufende Versetzungen gebildetes dichtes Netzwerk von Versetzungslinien ohne Ausscheidungen.
Kinetik und Morphologie der Gitterumwandlung kubisch‐flächenzentriert → hexagonal
Authors: Schumann H.
Published: July 2007

An einer Legierung aus Eisen mit, 26,12% Mangan wurden die Kinetik und Morphologic der Umwandlung von kub.‐flz. Austenit in die hexagonale ε‐Phase metallographisch untersucht. Im Austenitkorn entsteht zunächst auf einer Oktaederfläche ein Stapelfehler, der sich vergrößert, eine linsenförmige Gestalt annimmt und schließlich zu einer dünnen Platte anwächst. Dieser Vorgang stimmt mit dem Seegerschen Versetzungsmodell überein. Beim Auftreffen auf ein Hindernis wird ein mechanischer Druck erzeugt, der zu einer plastischen Verformung führt. Das Dickenwachstum der ε‐Platten ist wegen der beträchtlichen Umwandlungskontraktion begrenzt. Trotz des plättchenförmigen Aufbaus kann die hexagonale Phase jedes beliebige Volumen erfüllen, da durch einen besonderen, bisher noch nicht ganz geklärten Mechanismus eine Art Paketbildung erfolgt. Auf Beziehungen zwischen Zwillingsbildung und ε‐Phase wird hingewiesen.
Synthetische faserige Fluoramphibole mit isomorph substituierten Kationen und ihre Haupteigenschaften
Authors: Fedoseev A. D. , Grigorjeva L. F. , Chigareva O. G. , Krupenikova Z. V. , Romanov D. P.
Published: July 2007

Ausgehend von der allgemeinen Formel der Fluoramphibole X2‐3 Y5Z8O22F2 wurden, in einer Versuchsserie mit Mg2+ auf der Y = Position auf die X‐Position Na+, K+, Rb+, Sr2+ und Ba2+ substituiert, in einer zweiten Versuchsserie wurde mit Na+ auf der X‐Position das Mg2+ der Y‐Position teilweise durch Cu2+, Mn2+, Fe2+, Co2+, Ni2+ Fe3+ und Cr3+ ersetzt.

Die Isomorphiebeziehungen der auf diese Weise synthetisierten Amphibole werden diskutiert. Gitterparameter, Brechungsindizes, Erhitzungskurven, chemische Beständigkeit, einige mechanische Eigenschaften (insbesondere die Zugfestigkeit der Faserkristalle in Abhängigkeit von ihrem Durchmesser) sowie Ergebnisse elektrischer Messungen werden mitgeteilt.
Zur Darstellung von WO2‐ und W20O58‐ Kristallen durch chemische Transportreaktionen
Authors: Kleber W. , Raidt H. , Dehlwes U.
Published: July 2007

Es wurde die Darstellung von WO2‐ und W20O58‐Einkristallen durch chemische Transportreaktionen untersucht. Die Experimente erfolgten in abgeschlossenen Quarzglasampullen nach dem Diffusionsverfahren mit Chlorwasserstoff und Chlor als Transportgase und im Temperaturgebiet zwischen 650°C und 1000°C. Die gewonnenen Kristalle werden beschrieben, und die Abhängigkeit der Kristallgröße von Ampullenquerschnitt, Temperaturgradient und Transportdauer wurde geprüft. Die Identifizierung der gezüchteten Kristalle erfolgte röntgenographisch.
Growth of zinc single crystals from the vapour phase in a hydrogen atmosphere
Authors: Nanev Chr. , Iwanov D. , Nenow D.
Published: July 2007

The formation of cavities on the crystal surface was observed during the growth of zinc (and cadmium) single crystals from the vapour phase in the presence of hydrogen. This effect which is most pronounced on the {0001}‐face is a result of the diffusion of zinc vapour in hydrogen and is considered to be due, according to the kinematic theory of the growth forms of crystals, to the inhomogeneous supersaturation over the crystal surface. The experimental results are in accord with CHERNOV'S theoretical considerations concerning the critical size above which the formation of a cavity occurs.
Growth of alkali halide crystals with a lowered concentration of oxygenous anions using SiX4 as a removing agent
Authors: Eckstein J. , Gross U. , Rubinová E.
Published: July 2007

Three variants of a procedure for treatment of alkali halide melts by means of SiX4 are described. Each of these ways succeeded the solidified melt no more sticking to the walls of the quartz crucible. Thus prepared barrels are convenient to further adaptation by zonal refining or for crystal growing, e.g. by the crucible lowering method.

Chemistry of SiX4 effect on the hydrolysis products and some other oxygenous anions in alkali halides melts is dicussed.
Preparation of Non‐Wedge‐Shaped KDP and DKDP Crystals
Authors: Mareček V. , Dobiášová L. , Novák J.
Published: July 2007

Optimum conditions for the preparation of non wedge‐shaped KDP and DKDP crystals have been studied. The effect of pH of the crystallisation solution, cation admixtures and speed of agitation on the quality of crystals is presented. The working procedures for the preparation of non wedge‐shaped crystals of both species are given.
Innere Spannungen in Korundeinkristallen (I) Die Messung der Spannung
Authors: Kvapil Jiří
Published: July 2007

Es wurde das Verhältnis zwischen den Werten der Spannung ermittelt, die aus der Spannungsdoppelbrechung und dem optischen Achsenwinkel der Kristallkuppe von Korundbirnen berechnet wurden. Dabei wurde experimentell der folgende Zusammenhang gefunden:

.
Investigation of the Concentration Ratios at the Solid‐Liquid Interface
Authors: Krumnacker Maja , Lange Werner
Published: July 2007

A method for studying experimentally the concentration ratios at the interface has been developed, the tracer technique being applied for detecting the solute concentration. The studies refer to the system Sn–Zn. For concentrations of 0.1 down to 0.03% Zn and for different growth rates, curves are plotted representing the concentration distribution in quenched speciments. These curves, within the region of interface, are based on measuring points arranged at intervals of about 50 microns, which ensure to determine accurately the concentration ratios. The width of the diffusion boundary layer was found to be equal to 100 up to 300 microns. Thus it is of the same order as the value calculated form theory using distribution coefficients found by experiments.

The concentration distribution characterized by two parameters, viz., by the quotient of C/CL corresponding to the ratio of keff/k0 and by the quotient of CS/C = k0. For low initial concentrations and growth rates, correspondence of the values found by experiments with those to be expected from theory could beattained. The deviations occurring with higher concentrations and growth rates are explained by microsegregation phenomena.
Beitrag zum lichtmikroskopischen Nachweis von Versetzungsnetzwerken nach thermischen Behandlungsschritten im Silizium
Authors: Fricke P.
Published: July 2007

Es wird über ein Ätzverfahren berichtet, bei dem es unter Verwendung des Chromätzers mit gleichzeitiger Erhöhung der Bildkontraste bei der mikroskopischen Betrachtung der Ätzstrukturen möglich ist, Einzelversetzungen und Versetzungsnetze darzustellen, die einen geringen Winkel mit der Probenoberfläche bilden und direkt unter ihr angeordnet sind. An einigen typischen Beispielen von verschieden thermisch behandelten Siliziumscheiben werden die entstehenden Ätzstrukturen beschrieben und gedeutet.
Die Kristallisation von Polyphosphaten und Polysilicaten
Authors: Jost K.‐H. , Wolf H. , Worzala H. , Thilo E.
Published: July 2007

Durch Röntgeneinkristall‐Untersuchungen wurde nachgewiesen, daß sich die Anionenketten kristalliner Polyphosphate und ‐silicate durch Anlagerung von PO3‐ bzw. SiO32‐Gruppen aus der Schmelze an den wachsenden Kristall bilden.
Zur Züchtung von Kupfer(II)‐oxid über chemische Transportreaktionen
Authors: Kleber W. , Raidt H. , Klein R.
Published: July 2007

Es wird über Versuche berichtet, mit Hilfe von chemischen Transportreaktionen mit HBr als Transportmittel CuO‐Einkristalle herzustellen. Die Abhängigkeit des Habitus, der Größe und der Perfektion der Kristalle von verschiedenen Versuchsparametern, insbesondere von der Temperaturdifferenz und vom Füllgasdruck wurde untersucht.
Emissionselektronenmikroskopische Untersuchungen zur selektiven Materialabtragung durch Ionenätzen an intermetallischen Verbindungen
Authors: Wetzig K. , Wittig H.
Published: July 2007

In einem Emissionselektronenmikroskop wurden an verschiedenen intermetallischen Verbindungen Untersuchungen zur Materialabtragung beim Ionenätzen durchgeführt. Da die Abbildungselektronen durch den Ionenbeschuß ausgelöst wurden, konnte das zeitliche Fortschreiten der Ionenätzung unmittelbar beobachtet werden. Bei dem untersuchten Probenmaterial handelte es sich um die Lavesphasen NbFe2 und TaFe2 mit Einlagerungen der μ‐Phasen NbFe bzw. TaFe.

Für verschiedene Beschußionen und Probentemperaturen wurden die in Abhängigkeit von der Beschußdauer beobachteten Ätzstrukturen photographisch festgehalten. Anhand eines einfachen Modells für die durch Ionenbeschuß hervorgerufene Materialabtragung polykristalliner zweiphasiger Objekte wurde eine quantitative Auswertung des Bildmaterials versucht. In allen untersuchten Fällen wurden die Lavesphasen stärker abgetragen als die eingeschlossenen μ‐Phasen. Die Materialabtragung nahm außerdem mit steigender Objekttemperatur und wachsender Massenzahl der Beschußionen zu.
Probleme und Erfahrungen beim Betrieb von Pulverzuführungen
Authors: Müller R. , Ouart H. , Warm R.
Published: July 2007

Es werden verschiedene Pulverzuführeinrichtungen bezüglich des gleichmäßigen Pulverfalls miteinander verglichen. Des weiteren wird eine verbesserte Pulverzuführeinrichtung beschrieben, und es werden die Einflüsse des Pulvers als auch des apparativen Aufbaus auf den Pulverfall sowie die Abhängigkeit der Pulverfallrate von der Spulenspannung und der Erregerfrequenz des Schwingmagmagneten sowie der Niveauhöhe im Pulverbehälter der Dosiereinrichtung diskutiert.
A study of the rate‐controlling stage of the process of crystal growth in solutions
Authors: Bliznakov G. , Kirkova E. , Nikolayeva R.
Published: July 2007

The effective activation energies of crystal growth on the faces (100) of KCl, KBr, and KI crystals in water solutions have been determined. The values obtained have been compared with the respective crystal lattice energies according to Sletter and Mayer, as well as with the experimental ones. The activation energies of crystal growth are in strictest linear dependence on the heats of dehydration of the ions. This shows that the dehydration of the ions is most probably the rate‐controlling stage of the process of crystal growth in solutions. This concept is supported by the results of an experimental study of the rates of growth on the faces (111) and (100) of NaClO3 crystals.
Relative stability of zincblende and wurtzite structure in AIIBVI‐compounds
Authors: Däweritz L.
Published: July 2007

Zur Abschätzung der relativen Stabilität der kubischen und hexagonalen Phase der Sulfide, Selenide und Telluride von Zink und Cadmium werden die Gitterenergien nach der Born‐Landé‐Gleichung berechnet. Aus den erhaltenen Werten ergibt sich eine Zunahme der Beständigkeit der Zinkblendestruktur in der Reihenfolge CdS‐ZnS‐CdSe‐ZnSe‐(CdTe)‐ZnTe. Das steht in Übereinstimmung mit der Abschätzung der Stabilität aus den Elektronegativitätsdifferenzen der Komponenten, den experimentellen Erfahrungen aus der Kristallzüchtung und der Kristallisation dünner Schichten sowie den Polytypieerscheinungen an AIIBVI‐Verbindungen. Die relative Stabilität der Zinkblende‐ und Wurtzitstruktur kann durch Abweichungen von der Stöchiometrie beeinflußt werden.
Erfahrungen mit der Funkenerosiven Bearbeitung von Antimoneinkristallen
Authors: Doerschel J. , Fischer G.
Published: July 2007

Es wird ein einfaches Gerät für die funkenerosive Bearbeitung von Einkristallen beschrieben, das besonders für Antimon verwendet wurde. Diese Einrichtung gestattet die Herstellung von Proben unterschiedlicher Formen und Abmessungen sowie verschiedener kristallographischer Orientierungen.

Die funkenerosiv getrennten Antimonkristalle wurden in Hinsicht auf Oberflächenbeschaffenheit (Rauhtiefe) und Ausdehnung des plastisch deformierten Bereiches (Deformationszwillinge und Versetzungen) in Abhängigkeit von der maximalen Speicherenergie des Kondensators untersucht. Entstehung und Verteilung der Vorformungsstrukturen kann auf Basis der wirksamen Schubspannung (Schmid‐Faktor) im Gleit‐ bzw. Zwillingssystem gedeutet werden.
Herstellung von Rubin‐Saphir‐Übergängen
Authors: Müller R.
Published: July 2007

Es werden die Herstellung von Rubin‐Saphir‐Übergängen beschrieben und Angaben über die optische Qualität der Übergänge gemacht.