bluuebunny/crossref_metadata_2025 huggingface dataset:
Eliciting compliance from Warlords: the ECOWAS experience in Liberia, 1990–1997
Authors: Aning Emmanuel
                      Kwesi
Published: July 2007

This article examines the strategies initiated by the Economic Community of West African States (ECOWAS) to elicit compliance with its disarmament policies from belligerents in Liberia's 1989–96 civil conflict. I propose to tackle the task within a linked and holistic four‐fold approach. First, I situate ECOWAS's intervention in Liberia from 1990 to 1997 within the changing context of international perceptions of multilateral organisation involvement in civil wars. ECOWAS's intervention had different diplomatic phases. The first phase under the Standing Mediation Committee lasted from May 1990‐June 1991, The Committee of Five Process from June 1991‐August 1992, and the Committee of Nine Process from September 1993‐July 1997. Second, I analyse the background for the collapse and the dynamics which fuelled the war in Liberia. Third, I make an empirical analysis of ECOWAS's strategies to elicit compliance from faction groups. I conclude by discussing the impact and lessons of ECOWAS's strategies in Liberia. My argument is that ECOWAS's capability to elicit compliance from faction groups as opposed to state actors was limited partly because ECOWAS was not geared towards dealing with these new kinds of actors, that the nature of international relations does not have ‘room’ to consider the interests and demands presented by such actors, and that the normal forms of sanctions and ‘corrective’ measures applied against states in interstate relations are not always effective when applied to faction groups.
Warfare, endemic violence & state collapse in Africa
Authors: Allen Chris
Published: July 2007

African politics in the nineties have been marked by a series of violent breakdowns of order, and in some cases the disappearance of the central state, in a large number of states. Attempts at the analysis of this phenomenon have involved several different but complementary approaches, notably those invoking globalisation, the economics of ‘new’ war, the crisis of the neopatrimonial state, or social and cultural factors as keys to explanation. These either confine themselves to case studies, or treat all instances of endemic violence as open to the same analysis, in part because they treat violence or warfare as themselves the central objects of analysis. An alternative approach does not see ‘war’ as the problem, but is instead concerned with the historical circumstances within which endemic violence occurs and which can be seen as possible causes of that violence.

This approach allows for the simultaneous existence of several different historical sequences involving war and violence, and identifies one key category of cases of endemic violence which covers the great majority of those cases in the nineties: violence associated with the process of state collapse in Africa. It attributes the origins of violence in these cases to the degeneration of their ‘spoils politics’ systems under the impact of their internal dynamics, accelerated by economic decline since 1980 and the end of the Cold War. As spoils systems develop into ‘terminal spoils’, so violence intensifies and takes on new but necessary forms, and a process of state collapse begins, interacting with the growth of violence in ways that accelerate both.
Awareness of Beyondblue: The National Depression Initiative in Australian Young People
Authors: Morgan Amy , Jorm Anthony
Published: July 2007

Objective: To measure awareness of beyondblue: the national depression initiative and Ybblue (the youth program of beyondblue) in Australian young people and associations between awareness and measures of mental health literacy.

Method: A national telephone survey of mental health literacy was conducted with 3746 young people aged 12–25 years. Participants were asked to spontaneously recall organizations related to mental health problems, as well as whether they recognized beyondblue.

Results: Overall, 44% of young people were aware of beyondblue, including 12.1% who spontaneously recalled beyondblue as an organization related to mental health problems. Awareness was lower in males and generally increased with age. Awareness of beyondblue was associated with better recognition of depression and greater exposure to depression in self or family and friends. Participants aware of beyondblue were more likely to rate antidepressants and some professional interventions as helpful for depression, and were less likely to rate dealing with the problem alone or using alcohol as helpful. Awareness was not associated with social distance scores or psychological distress.

Conclusions: beyondblue: the national depression initiative has reached a good proportion of Australian young people, and awareness is associated with better mental health literacy. Males and younger adolescents could be targeted for improvements in awareness.
Expanded Practice Roles for Community Mental Health Nurses: A Qualitative Exploration of Psychiatrists’ Views
Authors: Elsom Stephen , Happell Brenda , Manias Elizabeth , Lambert Tim
Published: July 2007

Objective: The aim of this paper was to explore the perspectives of psychiatrists regarding the potential impact of expanded nursing practice roles on mental health care delivery.

Method: In-depth interviews and a focus group were conducted with psychiatrists from metropolitan and rural Victoria, Australia, using a qualitative exploratory design.

Results: Four main themes emerged: nurses’ preparation to undertake expanded practice; power and autonomy of nurses; final responsibility rests with psychiatrists; and, the future of expanded nursing practice. Participant responses to these themes were varied and diverse.

Conclusions: Participant responses elucidate the complexity of the issues and suggest that a number of factors influence psychiatrists’ opinions of the expanded practice role.
Overview of Psychiatric Ethics III: Principles-Based Ethics
Authors: Robertson Michael , Ryan Christopher , Walter Garry
Published: July 2007

Objective: The aim of this paper is to consider the application of principle-based medical ethics to psychiatry.

Conclusions: Principles-based medical ethics is a useful tool for resolving ethical dilemmas in psychiatryin that clinical aspects of ethical dilemmas can be better articulated then in other methods. The ethical dilemmas unique to psychiatry, such as those related to impairment of autonomy, present a challenge to the method. After considering a case example, we conclude that psychiatrists can best utilise a principles based approach to ethical dilemmas when they combine this with a level of critical reflection in the light of other ethical theories, such as virtue ethics, as well as close consideration of the clinical and social context of the ethical dilemma.
Clinical Supervision in Advanced Training in Child and Adolescent Psychiatry: A Reflective Practice Model
Authors: Senediak Christine , Bowden Michael
Published: July 2007

Objective: This paper aims to provide a model for supervision in advanced training in child and adolescent psychiatry that is in keeping with adult learning principles and that gives supervisors a framework that allows fulfilment of their multiple roles. Guidelines to develop reflective practice in trainees, thus enhancing clinical competence and life-long learning, are presented.

Conclusions: Reflective practice in supervision encourages the development of competence in trainees. This model is especially relevant for training in child and adolescent psychiatry, but can also be applied to other subspecialty training areas.
Awareness of risk of osteoporosis may cause uncertainty and worry in menopausal women
Authors: Hvas Lotte , Reventlow Susanne , Jensen Hans L. , Malterud Kirsti
Published: July 2007

Aims: A study was undertaken to explore how menopausal women are affected by awareness of potential risk of osteoporosis. Methods: A qualitative interview study, including analysis of in-depth interviews with 17 women who independently gave views on risk, out of 24 women interviewed about their menopausal symptoms. The women were selected on the basis of a survey including 1261 women chosen at random, to cover a broad spectrum of Danish women, their menopausal experiences, and contact with the healthcare system. The study was part of a larger project targeting menopause. Results: Awareness of osteoporosis risk caused a feeling of uncertainty and worry in some women. Only women reacting in this way seemed to act in order to prevent future fractures. The affected women were puzzled to realize that risk-reducing medication could introduce new hazards. Most of the women had heard about osteoporosis related to menopause as culturally embedded knowledge. Conclusions: Making individual women uncertain and worried must be considered a potentially serious side effect of health promotion. The findings raise the question of whether introducing healthy people to the threat of future diseases is ethically justifiable. As hormonal treatment is no longer recommended for long-term use, it is suggested that the strong link between osteoporosis and menopause should be toned down when counselling menopausal women.
Consultations for injuries by frequent attenders are found to be medically appropriate from general practitioners' perspective
Authors: Bergh Håkan , Baigi Amir , Marklund Bertil
Published: July 2007

Aims: A study was carried out to determine whether frequent attenders' (FAs') consultations for injuries are medically appropriate or not. Methods: A retrospective review was undertaken of medical records in a primary healthcare centre. All injury consultations by frequent attenders and controls during a period of one year were evaluated by two general practitioners (GPs). Outcome variables were: number of injuries, chronic diseases, type of injuries, and their treatments. The GPs made a comprehensive picture of each case and evaluated whether it was medically appropriate to consult a doctor or not. Results: Injuries were 7.2 times more common among frequent attenders compared with the controls. Frequent attenders had significantly more chronic diseases. Mean number of injury consultations was the same for frequent attenders with or without chronic disease. There was no difference concerning medically appropriate consultations between frequent attenders and controls. Conclusions: Consultations for injuries with frequent attenders were considered medically appropriate. Chronic diseases did not explain the higher injury incidence among frequent attenders. These findings are interesting and contradict the opinion that increased healthcare consumption by FAs is a waste of resources. Our findings may suggest that FAs are more vulnerable individuals.
From healthy survivors to sick survivors — implications for the twenty-first century
Authors: Rosen Mans , Haglund Bengt
Published: July 2007

Background: Hypotheses concerning compression of morbidity have gained support, particularly due to improved lifestyles from 1950 to date, but now the increase is largely due to improvements in healthcare. Methods: Survey data from Sweden were used to test whether the older population aged 65—84 years during 1995—2002 had more longstanding illnesses than the older population of 1980—87 or 1988—94. Results: There was an increased prevalence of many longstanding illnesses among the elderly in Sweden between 1988—94 and 1995—2002. The increase was especially pronounced among those with at least three longstanding illnesses. For diabetes, heart disease, and hypertension, the prevalence among elderly men increased by over 20%. However, those reporting these kinds of longstanding illnesses perceive improved health and are less restricted in their daily activities. Conclusions: Results from Sweden indicate that many countries approaching Sweden's life expectancy will have an increased need for care for the oldest population in the future. The compression-of-morbidity hypothesis is being challenged, probably due to improvements in healthcare.
Children Read Normal and Reversed Letters: A Simple Test of Reading Skill
Authors: Staller Joshua , Sekuler Robert
Published: July 2007

Above- and below-average readers in grades 3, 5 and 7 named letters under two conditions. In one condition, letters were presented in normal orientation. In the other condition, letters were presented in left-right mirror image orientation. The ratio of (1) naming time on normal letters to (2) naming time on mirror image letters was calculated for each child. Good readers had lower ratios than poor readers. This was due primarily to the faster naming of normal letters by good readers. Good and poor readers named mirror image letters at similar speeds. Two possible explanations for the results are discussed. One explanation is that the skilled readers have a better memory for the normal orientation of the letter shapes. A second explanation is that skilled readers process more peripheral information, when naming, than their less skilled counterparts, but that this peripheral processing is curtailed when transformed text is presented.
Component Problems in Dichotic Listening
Authors: Dennis Ian
Published: July 2007

The experiments reported examined monitoring for semantically defined targets whilst concurrently shadowing (Experiment I) or listening silently (Experiment II). The word lists for monitoring were either visual or auditory. Monitoring and shadowing accuracy showed less interference when presentation was bimodal than when it was dichotic. However, monitoring latency and recognition memory for shadowed material did not show this effect. It is argued that these data reveal the existence of a number of different sources of potential difficulty in dichotic listening situations and the nature of these is discussed.
Theory and Practice in the National Youth Anti-Drug Media Campaign
Authors: Worden John K. , Slater Michael D.
Published: July 2007

This article will review the role of behavioral theory in the National Youth Anti-Drug Media Campaign and then will identify lessons learned as the Campaign evolved to adjust to new insights and the realities of the mission. It should be noted that the primary dependence on national advertising, as opposed to a more integrated campaign using community-based or other media and social marketing strategies, or a more targeted, segmented campaign, was a premise of the Campaign as authorized by Congress. In other words, the role of social science was limited primarily to identifying desired attitudinal and behavioral outcomes and to helping develop message platforms and briefs that might help achieve those outcomes. Although social science input was not invited with respect to the broader strategic issues in prevention communication strategy, its application in the design and implementation of a major national media campaign has been a unique opportunity worthy of documentation and further consideration.
Individual Preference and Optimal City Size
Authors: Price Colin
Published: July 2007

The desirability of city size can only be judged in relation to the preferences of individuals for production and consumption economies and diseconomies of scale. A model based on plausible utility functions and the free migration of utility-maximising individuals generates a well-spaced city hierarchy, reasonably able to satisfy the population's tastes. It can adjust to population growth or change of taste without serious over-enlargement of cities. Minor interference with it would doubtfully produce net benefit. Rather than externalities in themselves, it is the combination of externalities with inertia that may create suboptimal city hierarchies.
A Study of the Formal Structure of J. W. Forrester's Urban Dynamics Model
Authors: Beumer L. , van Gameren A. , van der Hee B. , Paelinck J.
Published: July 2007

The 118 basic equations of Forrester's urban dynamics model are analysed by forming them into qualitative structural matrices. It is concluded that the endogenous dynamics of the system are determined by only 42 of the 118 stock variables, thus enabling the majority of the equations to be discarded. In the urban dynamics model, city growth behaviour is found to depend essentially upon an attractiveness-mobility base which conditions labour and unemployment change rates and these in turn influence change rates in housing and management and finally new and mature business growth rates.
Industrial Restructuring versus the Cities
Authors: Massey Doreen B. , Meegan Richard A.
Published: July 2007

The paper argues that changes in the national economy are important in an explanation of inner city job changes and focuses upon structural reorganisation in the electrical, electronics and aerospace equipment sectors. In the survey firms, these sectors lost over 36,000 jobs in the study period, most of them in London, Manchester, Merseyside, and Birmingham. The elimination of excess capacity and the need to cut costs are identified as the most important restructuring process. Most of the job losses are caused by closures or contractions with about one quarter due to contraction with relocation and about 10 per cent due to movement from the cities without contraction.
The Evaluation of Urban Change: Equilibrium and Adaptive Approaches
Authors: Vickerman R.W.
Published: July 2007

The paper is concerned with the problem of providing a basis for the evaluation of major changes in urban infrastructure. Recent developments in general equilibrium modelling of urban systems have tackled these interdependencies between sectors which cause problems in the use of traditional partial equilibrium approaches. However, while such models offer valuable insights into the working and dynamic development of urban systems their use in assessing the overall effects of particular projects seems limited. The argument advanced is that these questions can better be answered by moving out of the equilibrium framework and concentrating on the adapative mechanisms linking decisions in the various urban sectors. The framework of a model is outlined and discussed in terms of the current debate on Inner City Areas.
Habitability Laws and the Shrinkage of Substandard Rental Housing Stock
Authors: Hirsch Werner Z. , Law Cheung-Kwok
Published: July 2007

Recent years have seen a great upsurge in the number and types of laws that control the relationship between landlords and tenants. Particularly important among such laws are those which extend the warranty of habitability, often referred to as habitability laws. They award tenants new powers by substituting for the doctrine of caveat emptor the doctrine of caveat venditor. This paper examines the effects which habitability laws have had on the stock of substandard rental housing. Substandard housing is defined in four different ways, and for each a separate equation is estimated for the period 1960 to 1974-75. The most stringent of such laws - receivership laws - are found to have a statistically significant effect on the reduction of substandard housing in SMSAs. Specifically, between 1960 and 1974-75 in the presence of receivership laws the stock of substandard rental housing was found to have decreased on the average between 1.4 and 4.6 per cent, depending on how substandard is defined.
Identification of Industrial Clusters and Complexes: a Comparison of Methods and Findings
Authors: Czamanski Stan , Ablas Luiz Augusto de Q.
Published: July 2007

The paper reviews systematically studies dealing with the identification of clusters and complexes, or of groups of industries linked by flows of goods and services, or showing significant mutual locational attraction. The studies are classified according to the method used for identification, and to their spatial focus. Some 60 types of industrial groupings have been found to exist by the various students of spatial aggregation of industries but many showed only small differences in their sectoral composition. The similarity of results despite the diversity of methods used, degree of sectoral disaggregation, and areas examined was striking. A set of tables comparing the findings is presented along with a detailed analysis of methods and results.
The Effect of Crowding on Behaviour: Empirical Measures for Testing Theoretical Models
Authors: Dunstan John
Published: July 2007

The manner in which density and crowding were measured in Melbourne, Australia, was found to be of crucial importance in explaining the observed relationships between these variables and human pathology measures. The more theoretically relevant measures of density and crowding displayed higher correlations with human pathology measures than less theoretically relevant measures. It was concluded that contradictory findings in the literature regarding the importance of density and crowding as determinants of human behaviour can be attributed in part to the failure of researchers to specify measures of density and crowding appropriate to the theoretical models they are testing.
Macro Evaluations of the Impact of Regional Policy in Britain: a Review of Recent Research1
Authors: Schofield J.A.
Published: July 2007

Regional policies may be assessed from at least three separate perspectives: their impact on the regional distribution of economic activity (their primary purpose), their aggregate efficiency effect on the economy (contribution to national output net of resource cost) and their financial impact on the national Treasury (net Exchequer costs). This paper reviews the considerable effort directed since the turn of the 1970s towards evaluation of these effects in Britain. So far as the impact of policy on the regional distribution of economic activity is concerned, the paper classifies studies according to quantitative methods used (simple statistical analysis, shift-share analysis and regression analysis) and emphasises the strengths of the latter over the others, showing that, without as yet being used entirely satisfactorily, models useful for policy assessment are developing. So far as aggregate policy effects (economic and financial) are concerned, there is more ground to be broken, although the outline of a basic model is emerging.
Subjective Assessments of Neighborhood Quality by Size of Place
Authors: Dahmann Donald C.
Published: July 2007

Objective indicators suggest that numerous aspects of the quality of residential environments decline with increasing size of place. As human responses to the environment are based in part on perceptions and evaluations of conditions rather than their objective status, subjective indicators should also be considered in assessing the quality of residential environments in different-sized places. A series of subjective response measures for a full range of urban places in the United States show that (1) the perceived overall quality of neighborhoods declines with increasing size of place, even when controlled for subjective responses to individual local conditions, (2) most of the surveyed local deficiencies are reported to be more widespread in larger cities, (3) the intensity of responses to conditions depicting deterioration of the built environment and public safety increase more rapidly with city size than do responses to traffic-transportation conditions, (4) there appears to be a breakpoint in the general decline of neighborhood quality between large and extremely large urban centers, and the suggestion that residential quality in the smallest urban places is not as good as in places of over 10,000 population.
Increasing Returns to Scale and Location Theory of the Firm Under Price Uncertainty
Authors: Shieh Yeung-nan
Published: July 2007

This paper shows that it is not appropriate to consider increasing returns to scale in the location theory of the firm, when the production function is assumed to be concave. The paper assumes that the production function is quasi-concave. If the marginal revenue curve cuts through the marginal cost curve from above only once, then comparative static analysis can be applied in the case of increasing returns to scale.
Workplace Location, Residential Location, and Urban Commuting
Authors: Simpson Wayne
Published: July 2007

Analysis of urban structure normally involves models of residential location in which workplace location is predetermined, despite the disappointing explanatory power of these models. This paper re-examines a model in which workplace location, based on economic principles of spatial job search, and residential location are simultaneously determined. Empirical results for Toronto support the model and closely resemble earlier results for Greater London. New tests of the model for household heads and homeowners also confirm predictions. The model is then extended to explain urban commuting distances. It is found that the model of workplace and residential location explains urban commuting distances better than models of residential or workplace location alone.
Brazilian Red Propolis—Chemical Composition and Botanical Origin
Authors: Daugsch Andreas , Moraes Cleber S. , Fort Patricia , Park Yong K.
Published: July 2007

Propolis contains resinous substances collected by honey bees from various plant sources and has been used as a traditional folk medicine since ca 300 BC. Nowadays, the use of evidence‐based complementary and alternative medicine (CAM) is increasing rapidly and so is the use of propolis in order to treat or support the treatment of various diseases. Much attention has been focused on propolis from Populus sp. (Salicaceae) and Baccharis dracunculifolia (Asteracea), but scientific information about the numerous other types of propolis is still sparse. We gathered six samples of red propolis in five states of Northeastern Brazil. The beehives were located near woody perennial shrubs along the sea and river shores. The bees were observed to collect red resinous exudates on Dalbergia ecastophyllum (L) Taub. (Leguminosae) to make propolis. The flavonoids of propolis and red resinous exudates were investigated using reversed‐phase high‐performance liquid chromatography and reversed‐phase high‐performance thin‐layer chromatography. We conclude that the botanical origin of the reddish propolis is D. ecastophyllum. In areas where this source (D. ecastophyllum) was scarce or missing, bees were collecting resinous material from other plants. Propolis, which contained the chemical constituents from the main botanical origin, showed higher antimicrobial activity.
Tankyrase-1 mRNA expression in bladder cancer and paired urine sediment: preliminary experience
Authors: Gelmini Stefania , Quattrone Silvia , Malentacchi Francesca , Villari Donata , Travaglini Fabrizio , Giannarini Gianluca , Della Melina Alessandro , Pazzagli Mario , Nicita Giulio , Selli Cesare , Orlando Claudio
Published: July 2007

Clin Chem Lab Med 2007;45:862–6.
Could standard ISO 15189 be useful for the conundrum of CA 19-9/GI Monitor measurement?
Authors: Dorizzi Romolo M. , Meneghelli Sandra , Rocca Maria , Ferrari Anna
Published: July 2007

No Absract available
Tumor necrosis factor-α and oxidant status are essential participating factors in unexplained recurrent spontaneous abortions
Authors: El-Far Mohamed , El-Sayed Ibrahim H. , El-Motwally Abd El-Gawad , Hashem Ikbal Abou , Bakry Nadia
Published: July 2007

Clin Chem Lab Med 2007;45:879–83.
Impact of genetic polymorphisms on the risk of lipid disorders in patients on anti-HIV therapy
Authors: Bonnet Eric , Genoux Annelise , Bernard Jacques , Fauvel Josette , Massip Patrice , Perret Bertrand
Published: July 2007

Active anti-HIV therapy can induce hypertriglyceridemia, low high-density lipoprotein (HDL) and insulin resistance, eventually accompanied by clinical lipodystrophy, associated loss of subcutaneous adipose tissue and an increase in abdominal adiposity. The frequency of these metabolic disorders is approximately 50% and host genetic factors might confer particular susceptibility. Variants of apolipoproteins (apo) A5 and C3, interacting with

Clin Chem Lab Med 2007;45:815–21.
Comparison of the Roche COBAS Amplicor™ Monitor, Roche COBAS Ampliprep™/COBAS Taqman™ and Abbott RealTime™ Test assays for quantification of hepatitis C virus and HIV RNA
Authors: Wolff Dietmar , Gerritzen Andreas
Published: July 2007

Clin Chem Lab Med 2007;45:917–22.
Über die Züchtung strukturreiner Zinksulfid‐Einkristalle
Authors: Hartmann Horst
Published: July 2007

Bei der Züchtung von Zinksulfid‐Einkristallen aus der Dampfphase erwiesen s°Ch Polytypie und eindimensionale Lagenfehlordnung als Wachstumserscheinungen. Eine während der Abkühlung mögliche Strukturumwandlung Wurtzit → Zink blende blieb ohne Einfluß. Als Folge einer Abhängigkeit des röntgenographisch bestimmten Fehlordnungsgrades von der Wachstumstemperatur traten in den Gebieten der Phasentransformation um 1020 und 1240 °C bei Zunahme der entsprechenden Fehlerwahrscheinlichkeiten häufig höherstufige Polytype auf. Kristalle im Anfangsstadium, also Whisker, Nadeln und dünne Tafeln waren immer strukturrein.

— Die Herausbildung der Fehlordnung wurde begünstigt durch: Wachstumstemperaturen in Nähe der Transformationsgebiete Zinkblende — Wurtzit, schlechte Temperaturkonstanz und steile Temperaturgradienten, Überlagerung der Diffusion durch Konvektion beim Materialtransport, spontanes Wachstum bei hohen Übersättigungen, Anreicherung von Kristallbaufehlern im Aufwachsbereich des Kristalls auf der Quarzwand sowie Fremdverunreinigungen.

Durch Einhaltung definierter Züchtungsbedingungen gelang es bei besonderer Berücksichtigung von Wachstumstemperaturen unterhalb 1000 °C oder zwischen 1100 und 1200 °C, relativ große ZnS‐Kristalle mit reiner Zinkblende‐ oder Wurtzitstruktur herzustellen. Höherstufige Polytype bildeten sich nicht strukturrein aus. Mit Hilfe von Temperungen in charakteristischen Temperaturgebieten konnten fehlgeordnete Kristalle nachträglich in kubische oder hexagonale umgewandelt werden. — Die durchgeführten Versuche weisen auf die Möglichkeit hin, die Entstehung von Polytypie und Lagenfehlordnung durch eine Modifizierung der Keimbildungsarbeiten zu erklären.
Die Natriumbikarbonat‐Kristallisation im Ammoniak‐Soda‐Prozeß
Authors: Felbinger Adolf , Neels Hermann
Published: July 2007

Im System NaCl‐NH3‐H2O wurde die durch die Karbonisierung bewirkte Kristallisation von NaHCO3 untersucht.

Es konnte die Abhängigkeit der Keimzahl von der Übersättigung und der Temperatur ermittelt werden. Die Zunahme der Keimzahl mit steigender Übersättigung folgt einer exponentiellen Abhängigkeit. Für die Zunahme der Keime bei fallender Temperatur wird eine Reaktionshemmung an der Phasengrenzfläche erwogen. Die gefundene Abhängigkeit von der Intensität des Rührens entspricht der bekannten Tatsache, daß mit steigender Turbulenz die Zahl der Kristalle zu‐ und ihre Größe abnimmt.

Die Wachstumsgeschwindigkeit der NaHCO3‐Kristalle wurde zunächst mit einer Genauigkeit bestimmt, die für praktische Rechnungen ausreicht.

Die freie Grenzflächenenergie σ wurde für 45 und 60 °C ermittelt.
Verneuil‐Züchtung von Einkristallen mit dem Hochfrequenz‐Plasmabrenner
Authors: Ardenne H. C. Manfred V. , Knebel Ernst Dieter , Wachtel H. , Wiese Peter
Published: July 2007

Das klassische Verneuil‐Verfahren verwendet als Energiequelle für die Züchtung von Einkristallen eine chemische Flamme, und zwar Wasserstoff und Sauerstoff im wechselnden Mengenverhältnis. Nach diesem Verfahren lassen sich alle Verbindungen als Einkristalle herstellen, die bis ca. 2600 °C kongruent schmelzen und gegenüber den Brenngasen unempfindlich sind, d. h. sich nicht leicht oxydieren oder reduzieren lassen. Diese Einschränkung der Anwendung des bekannten Verneuil‐Verfahrens wird durch den Hochfrequenz‐Induktions‐Plasmabrenner aufgehoben. Es lassen sich mit seiner Hilfe auf relativ einfache Art und Weise Temperaturen von 15000 °K und mehr erzeugen, wobei die Arbeitsatmosphäre willkürlich gewählt werden kann. Diese Eigenschaften der HF‐Plasmaflamme erschließen neue Verbindungen zur tiegelfreien Züchtung von Einkristallen. Der Aufbau einer Kristallziehanlage mit Hochfrequenz‐Induktions‐Plasmabrenner und einige erzielte Ergebnisse werden kurz beschrieben.
Die vollständige Bestimmung der Verschwenkung von Subkörnern durch eine röntgentopographische Methode
Authors: Berger H. , Bohm J. , Wadewitz H.
Published: July 2007

Es wird eine Methode beschrieben, mit der die Verschwenkung von Subkörnern in einer Kristalloberfläche vollständig nach Betrag und Richtung bestimmt werden kann. Hierzu werden Aufnahmen nach dem Parallelstrahl‐Verfahren durch Reflexion an zwei verschiedenen Netzebenenscharen des Kristalls benutzt. Für den unsymmetrischen Bragg‐Fall beim Parallelstrahl‐Verfahren wird die Abbildungsgeometrie abgeleitet. Als experimentelle Beispiele werden die Subkornverschwenkungen an einem Rubin‐ und einem Wolframeinkristall mit dieser Methode bestimmt.
Crystal Habits of the Zeolitic Minerals
Authors: Kostov I.
Published: July 2007

Using the anisometricity of the crystal lattice a generalization is put forward about the habit variation of the zeolitic minerals as dependent on some salient factors such as supersaturation, temperature and Al⇌Si substitution.

The fibrous zeolites natrolite, scolecite, thomsonite, and edingtonite have 2 c/(a + b) ratios 0.30, 0.35, 0.51 and 0.68 respectively, that accounts for a tendency edingtonite to crystallize in short prismatic habits, natrolite invariably as acicular crystals. Higher supersaturations are considered favourable for the development of longer prismatic habits, whereas higher temperature and substitution of aluminium for silicium cause shortening of the habits. Laumontite displays a similar habit variation.

The foliated zeolites stilbite, epistilbite, heulandite, and brewsterite have 2 b/(a + c) ratios 1.46, 1.85, 2.20, and 2.41 respectively, hence results their tendency of variation from prismatic to thin tabular along the b‐axis, the first habit indicative for higher, the second for lower supersaturations. Al⇌Si substitution here again might play a habit modifying role.

The pseudoisometric zeolites gmelinite, chabasite, and levyne have c/a ratios 0.725, 1.086, and 1.686 respectively, and are in certain respects intermediate between the first two groups, here, however, the rhombohedron and basal pinacoid being the two main habit forms. Once again here Al⇌Si substitution should have to be considered as habit modifying factor, might be the case as also for change of the habit of analcime from icositetrahedron to cube.
Untersuchungen an Mikroeinkristallen aus Fällungen I Die Sulfate von Strontium, Barium und Blei
Authors: Espig H. , Neels H.
Published: July 2007

Die bei Zimmertemperaturen gefällten Sulfate von Strontium, Blei und Barium ändern Tracht und Habitus mit der Anfangsübersättigung. {001}, {210}, {101} sind wie bei den entsprechenden Mineralien neben {011}, {100} und {010} die Hauptformen. Aus der Bildung von Stufen auf {100} läßt sich schließen, daß es sich bei dieser möglicherweise nicht um eine F‐, sondern um eine S1‐Fläche handelt. Ähnliches deutet gelegentlich auch die Krümmung der Fläche {010} an.

Aus der Beziehung der mittleren Korngröße zur Anfangsübersättigung läßt sich auf ein optimales Fällungsgebiet schließen. Ebenso lassen sich daraus die günstigsten Bedingungen für ein periodisches Wachstum in Fällungen ableiten.
Die Synthese von CdSiP2 aus der Gasphase durch chemische Transportreaktionen
Authors: Valov Ju. A. , Plečko R. L.
Published: July 2007

In der vorliegenden Arbeit wird eine Methode zur Züchtung von Halbleiterkristallen der Verbindung CdSiP2 aus den Komponenten angegeben. Diese Methode ähnelt in einigen Punkten der Synthese von Verbindungen in einem Temperaturgradienten, unterscheidet sich jedoch von ihr dadurch, daß das Silizium durch eine chemische Transportreaktion in die Reaktionszone befördert wird. Auf der Grundlage der thermodynamischen Bewertung einiger Gleichgewichte in dem System, das sich beim Erhitzen von Cadmium, Silizium, Phosphor und eines Halogens in einer geschlossenen Ampulle bildet, wurde Chlor als das geeignete Halogen ausgewählt. Es wird gezeigt, daß im Chloridsystem SiCl4 bei erhöhten Temperaturen neben Cadmium beständig ist und infolgedessen am Transport des Siliziums teilnehmen kann. Außerdem kann das Silizium auch mit Hilfe des Cadmiumchlorids transportiert werden.

Die beschriebene Methode wurde verwendet, um bei Wahl geeigneter Versuchsparameter CdSiP2‐Einkristalle von maximal 12 × 3 × 1 mm3 Größe zu züchten.
Komplexe Zwillinge und Sphärolithe von Nahcolith (NaHCO3)
Authors: Aslanian S. , Kostov I. , Neels H.
Published: July 2007

In der Arbeit wird die Habitusänderung von Nahcolith‐Einkristallen in einem großen Übersättigungsbereich mit Hilfe einer Zirkulationsapparatur untersucht. Die Übersättigung erfolgte durch Abkühlung.

Bei niedrigen Übersättigungen entstanden Einkristalle. Höhere Übersättigung bewirkte größere Längen in der [001]‐Richtung. Bei mittleren Übersättigungen zeigen die Einkristalle allmähliche Übergänge in Kontaktzwillinge, später in Penetrationszwillinge und tafelige „Verwachsungszwillinge”︁. Bei hohen Übersättigungen verwachsen die tafeligen Zwillinge gegenseitig derart, daß sie Sphärolithe bilden. Dabei enthält jede neue Zwillingskombination die vorhergehenden.
The Preparation of Crystalline Lithium Fluoride by Controlled Precipitation
Authors: Jindra J.
Published: July 2007

By controlled precipitation from dilute aqueous solution of LiCl (resp. HF‐solution) a precipitate of lithium fluoride with perfect and homogeneous crystals was prepared. The growth of cubic grains with edge length about 50 μm and more was observed visually and microscopically. The supersaturation of the solution during precipitation was detected conductometrically. The growth of larger crystals forming clusters of LiF, occurs during slow cooling of solutions prepared by adding hot LiCl‐solution to hydrofluoric acid solution.
Untersuchung der gesetzmäßigen Verteilung Kleinster Fremdsubstanzmengen zwischen wachsenden KCl‐Kristallen und der Lösung (Bildung echter Mischkristalle)
Authors: Steinike U.
Published: July 2007

Es wurde die Verteilung zweiwertiger Schwermetallionen zwischen wachsenden KCl‐Kristallen und den gesättigten Lösungen untersucht. Die Schwermetallionen werden unter gleichzeitiger Bildung einer Kationenleerstelle auf K+‐Gitterplätze eingebaut. Der von den experimentellen Bedingungen abhängige Verteilungskoeffizient ist bei der Bildung echter Mischkristalle im allgemeinen konstant. Gefundene Abweichungen bei KCl: Cd2+‐Kristallen werden diskutiert. Die Größe des Verteilungskoeffizienten und damit die Tendenz zum Einbau nimmt mit steigender Abweichung der Ionenradien vom K+‐Radius ab. Für den Einbau ins Gitter ist nicht allein ausschlaggebend die Kationengröße. Die Art des Anions des zugesetzten Schwermetallsalzes ist von Bedeutung.
Beiträge zum Ätzen von Galliumarsenid (I) Strukturtheoretische Diskussion der erzeugten Ätzmorphologien
Authors: Neels H. , Voigt R.
Published: July 2007

{111}‐, {110}‐ und {100}‐Scheiben von GaAs wurden in verschiedenen Ätzmedien geätzt und die entstandenen Ätzstrukturen untereinander verglichen. Grundlage der Diskussion hierbei war die bestehende Korrelation zwischen Ätzgrubenmorphologie und Kristallstruktur. Wie sich zeigen läßt, finden unter Einbeziehung des Vorhandenseins primärer Baufehler als konstitutive Eigenschaft der Realkristalle sowie unter der Beachtung erfaßbarer Milieufaktoren die beobachteten mannigfaltigen Ätzerscheinungen auf {111}, {100} und {110} in der für GaAs charakteristischen Struktur ihre qualitative Deutung.
Zur Textur von Aufdampfschichten des Kupferphthalocyanins
Authors: Hamann C. , Wagner H.
Published: July 2007

α‐CuPc‐Aufdampfschichten von einigen μm Dicke und daraus durch thermische Umlagerung hergestellte β‐CuPc‐Schichten werden röntgenographisch und elektronenmikroskopisch untersucht. Aus den Polfiguren ergibt sich für die α‐Schichten eine bürstenartige Struktur mit einem Winkel von ca. 20° zwischen kristallographischer b‐Achse und der Substratnormalen. Daneben wird, offenbar als Anfangsstadium der Schichtbildung, eine höchstens 0,1 μm dicke Schicht mit parallel zur Substratebene orientierter b‐Achse beobachtet. Bei schonender Umlagerung zur β‐Modifikation bleibt die Struktur der α‐Schicht qualitativ erhalten; rasche Umlagerung führt zum Verlust der Textur. Die elektronenmikroskopischen Untersuchungen bestätigen diese Ergebnisse.
Einfluß der Substruktur auf die optische Homogenität von Rubin‐Laserstäben
Authors: Kvapil Jiří , Súlovský Jugaj
Published: July 2007

Es wird die Beziehung zwischen der Substruktur und der optischen Homogenität von aus 90°‐Einkristallen herausgeschliffenen Rubin‐Laserstäben beschrieben. Die optische Homogenität wurde interferometrisch und die Verschwenkung von Subkörnern mit der Parallelstrahlmethode und mit dem oszillierenden Spektrographen bestimmt.

Dabei wurde festgestellt: Die Komponente der Verschwenkung, welche die Drehung von Subkörnern um die zur Wachstumsachse und zur kristallographischen c‐Achse senkrechte Achse verursacht, ist der Zahl der Interferenzlinien proportional.
Bestimmung der Scheibenorientierung und Schichtdicke an epitaktischen Siliziumschichten auf Silizium
Authors: Fricke P.
Published: July 2007

Durch fehlerhaftes epitaktisches Wachstum entstehen in der epitaktischen Schicht Stapelfehler. Beim Wachstum an gestörten Substratstellen durchsetzen die Stapelfehler die gesamte Epitaxieschicht. Form und Größe der Stapelfehler sind abhängig von Schichtdicke und Scheibenorientierung. Für verschiedene Scheibenorientierungen (hk0), (hll) und (hhl) für h, k, l von 1 bis 10 bezogen auf die Ebenen (100), (110) und (111) werden die Stapelfehlerwinkel und die Seitenlängen der Stapelfehler für eine normierte Schichtdicke ermittelt und in Diagrammen aufgetragen. An Hand einiger Beispiele wird dieses Verfahren geprüft und mit herkömmlichen Methoden zur Bestimmung der Epitaxieschichtdicke und Scheibenorientierung verglichen.
Einsatz der Elektronenstrahl‐Mikrosonde bei der Lösung metallurgischer Werkstoffprobleme
Authors: Siegel U. , Schimmangk K. , Wulf K.
Published: July 2007

Die Elektronenstrahl‐Mikrosonde liefert über die Beschaffenheit metallischer Proben im Mikrobereich eine Vielzahl von Informationen, die in Verbindung mit einer geeigneten Meßmethode zahlreiche Aussagen zu wichtigen metallkundlichen Werkstoffproblemen ermöglichen. Aus der betrieblichen Praxis eines Edelstahlwerkes werden dazu als Beispiele die Identifizierung von Gefügebestandteilen, Bestimmung der Mikroseigerung, Untersuchung von Korngrenzen und Materialfehlern in Stählen erläutert.
Zur anisotropen Dilatation von Fe3S4‐Kristallen im elektrostatischen Feld
Authors: Yamaguchi S. , Wada H.
Published: July 2007

Ein synthetischer Kristall von Fe3S4 (Greigit, Spinelltyp, Gitterkonstante 9,87 ÅE) dehnt sich etwa 0,05 ÅE im elektrostatischen Feld (Feldstärke 860 Volt · cm−1) längs der [111]‐Achse bevorzugt (gegenüber anderen Richtungen) aus. Diese Eigenschaft, sich leicht zu deformieren, erschwert das Wachsen des Kristallits (Korngröße 300 ÅE) zum größeren Einkristall. Er wandelt sich bei der Präparation für das Wachstum in den hexagonalen Magnetkies um.
Elektrisch aktive Zentren in thermisch behandelten p‐Si‐Substraten und Si‐Homoepitaxieschichten
Authors: Kuschnerus S.
Published: July 2007

P‐Si‐Substrate mit und ohne darauf abgeschiedenen Si‐Homo‐Epitaxieschichten wurden im Vakuum bei 800 < T < 1000°C getempert und einer anschließenden schnellen Abkühlung auf Raumtemperatur unterworfen. Die dabei gebildeten elektrisch aktiven Zentren wurden bezüglich der Lage ihrer Energieniveaus, ihrer räumlichen Verteilung und ihres Ausheilverhaltens untersucht. Die beobachteten Zentren werden als atomare Fehlordnungskomplexe unter Beteiligung von Gitterlücken gedeutet.
Autoradiographic Investigations on the Incorporation of Ca Ions in KCl Crystals during Kyropoulos Growth
Authors: Beleites H. , Fröhlich F.
Published: July 2007

Ca doped KCl crystals were grown by the Kyropoulos method. 10−5 to 10−3 mole fractions of Ca (as CaCl2 with a small amount of Ca‐45 (β‐emitter)) were added to the melt. By autoradiography of suitable cleavage planes the incorporation of the Ca ions was found to take place preferentially in a periodic manner parallel to the solid liquid interface. In the case of a rotating seed there is a segregation process in which only one zone of maximum Ca content is built up like a helix throughout the whole crystal, the axis being identical with the growth axis of the crystal and the slope of the helix corresponding to the growth rate per seed rotation, this leading to striations of long range periodicity on vertical cleavage planes. In the case of a non‐rotating seed there is a different segregation process including a periodical incorporation too, but in discrete layers of relatively small separation parallel to the solid liquid interface in short range periodicity.

Explanations for the segregation phenomena are given in terms of periodically varying effective growth rates related to periodic temperature fluctuations in the neighbourhood of the solid liquid interface.
On certain dependences of the crystallization rate of supersaturation of a solution
Authors: Khamskij E. V.
Published: July 2007

A formula describing maximal precipitation rate of solutions in dependence on supersaturation is given. Experimental data of precipitation of barium nitrate are in good agreement with the results of calculation.
Die Kristall‐ und Molekülstruktur des 3,3′‐Diäthylthiacarbocyanin‐dichloroaurats
Authors: Falkenberg W. , Höhne E. , Sieler J. , Wagener R.
Published: July 2007

Die Kristall‐ und Molekülstruktur von C21H21N2S2AuCl2wurde mit Hilfe der Röntgenkristallstrukturanalyse bestimmt. Die Kristalle sind monoklin, Raumgruppe P 21/c mit 4 Molekülen in der Elementarzelle mita= 15,97 Å,b= 8,17 Å,c= 17,09 Å, β = 89,4°. Die Intensitätsdaten wurden nach der Filmmethode aus „equiinclination”︁‐Weissenbergaufnahmen gewonnen. Die Struktur wurde durch Schweratom‐Technik gesichert und durch least‐squares‐Methode bis zu einemR‐Wert vonR= 0,18 verfeinert. Das Farbstoffkation ist nicht ganz planar, die beiden Benzthiazolringe sind um einen Winkel von etwa 7° verdrillt. Im Kristall ordnen sich die Kationen zu zentrosymmetrischen Paaren an, die sich entlang derb‐Achse stapeln. Zwischen diesen Stapeln liegen die AuCl2‐Anionen in Abständen, die nur als van der Waalssche Kontakte zu interpretieren sind. Es wird ein intramolekularer AuS‐Abstand von 3.50 Å beobachtet.
The nucleation and precipitation of nickel ammonium sulphate crystals from aqueous solution
Authors: Mullin J. W. , Osman M. M.
Published: July 2007

A precipitation study has been made with nickel ammonium sulphate produced by mixing aqueous solutions of its constituent salts. Rates of nucleation, as indicated by the induction period, were measured for both agitated and non‐agitated systems over the temperature range 0–35 °C. The nucleation rate increases with increases in agitation and temperature but supersaturation has the dominant effect, as predicted by classical nucleation theory. However, attempts to analyse the results in accordance with classical theory were not entirely successful, but it is shown how the assumption of (a) a variation of crystal surface energy with temperature and (b) the influence of heterogeneous nucleation can account for the discrepancies.
Electron microscope study of cellular precipitation in ferritic iron‐zinc alloys
Authors: Budurov St. , Russev Kr. , Zlateva G.
Published: July 2007

Cellular precipitation in Fe/Zn system was studied by electron microscope methods.

Experimental results, obtained by Speich, Predel and Frebel and the present authors were used to test equation (3) of Cahn's theory.

The value of the specific surface energy σ of the Γ‐ferrite interface was determined to be about 2960 erg. cm−2.
Über die Flächenverteilung von Dekorationskeimen in der Umgebung von Versetzungen
Authors: Malicskó L.
Published: July 2007

Spalt‐ und Abdampfflächen von KCl: Me2+‐Einkristallen wurden mit Gold dekoriert. Die Flächenverteilung der Dekorationskeime wurde elektronenmikroskopisch untersucht. In der Umgebung von Versetzungsdurchstoßpunkten konnten charakteristische Veränderungen in der Dichteverteilung der Goldkeime beobachtet werden. Sie werden beschrieben und diskutiert.