Atomistic study of vibrational properties of γ-Al2O3

A study of the vibrational density of states (DOS) of γ-Al₂O₃ is presented. Four structural models from the recent literature are considered: vacant spinel model and three nonspinel models. The vacant spinel and one of the nonspinel models have unit cells with 40 atoms, while the other two models have 160 atoms. The interatomic interactions are computed using classical force fields that include Coulomb and van der Waals attractive interactions, short range repulsive interactions, as well as three-body terms. The oxygen polarizability is included via a core-shell potential. The DOS is compared with ab initio calculations recently published for the vacant spinel model. The classical and ab initio DOS show some differences for frequencies higher than 200 cm⁻¹, the ab initio having more peaks and having a frequency cutoff 100 cm⁻¹ lower than the classical DOS. The DOS of all models present some small differences. While the 160-atoms nonspinel models present a rather structureless DOS, 40-atoms models present peaks and dips relative to the 160-atoms models. The elastic constants of polycrystalline γ-Al₂O₃ are also estimated using several force fields. In general, the classical force field predict higher elastic moduli than the ab initio method. The infrared spectra of the four models are calculated.     

利用差示扫描量热法评价可热处理强化铝合金的析出模拟参数

利用差示扫描量热法（DSC）研究不同的固态相变反应。在特定的热处理周期中DSC信号和相的生成与溶解正相关。在基于时间和温度热处理周期中，DSC检测到的试样的热演变结果对于分析相演变和析出动力学极为重要。利用热／动力学模拟预测了6xxx和2xxx铝合金的热演变DSC信号。此模型同时考虑了不同亚稳相、稳定相、淬火残余空位的状态和影响。利用透射电镜和高分辨率电镜验证DSC曲线上特定峰值点析出相的形成、尺寸和密度。     

Dysregulation of Muscle-Specific MicroRNAs as Common Pathogenic Feature Associated with Muscle Atrophy in ALS,SMA and SBMA: Evidence from Animal Models and Human Patients

Motor neuron diseases (MNDs) are neurodegenerative disorders characterized by upper and/or lower MN loss. MNDs include amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), and spinal and bulbar muscular atrophy (SBMA). Despite variability in onset, progression, and genetics, they share a common skeletal muscle involvement, suggesting that it could be a primary site for MND pathogenesis. Due to the key role of muscle-specific microRNAs (myomiRs) in skeletal muscle development, by real-time PCR we investigated the expression of miR-206, miR-133a, miR-133b, and miR-1, and their target genes, in G93A-SOD1 ALS, Δ7SMA, and KI-SBMA mouse muscle during disease progression. Further, we analyzed their expression in serum of SOD1-mutated ALS, SMA, and SBMA patients, to demonstrate myomiR role as noninvasive biomarkers. Our data showed a dysregulation of myomiRs and their targets, in ALS, SMA, and SBMA mice, revealing a common pathogenic feature associated with muscle impairment. A similar myomiR signature was observed in patients’ sera. In particular, an up-regulation of miR-206 was identified in both mouse muscle and serum of human patients. Our overall findings highlight the role of myomiRs as promising biomarkers in ALS, SMA, and SBMA. Further investigations are needed to explore the potential of myomiRs as therapeutic targets for MND treatment.     

"Save angels perhaps": A critical examination of unconscious thought theory and the deliberation-without-attention effect.

Based on Unconscious Thought Theory (UTT) and a series of experimental and correlational studies, Dijksterhuis and his colleagues conclude that when making complex choices/decisions, conscious thought--deliberation while attention is directed at the problem--leads to poorer choices/decisions than "unconscious thought"--deliberation in the absence of conscious attention directed at the problem. UTT comprises six principles said to apply to decision making, impression formation, attitude formation and change, problem solving, and creativity. Because the implications of UTT for psychological research and theory are considerable, the authors critically examined these six principles (and the studies used to support them) in light of the extant scholarship on unconscious processes, memory, attention, and social cognition. Our examination reveals that UTT is a theory of the unconscious that fails to take into account important work in cognitive psychology, particularly in the judgment and decision making area. Moreover, established literatures in social psychology that contradict fundamental tenets of UTT and its empirical basis are ignored. The authors conclude that theoretical and experimental deficiencies undermine the claims of the superiority of unconscious thinking as portrayed by UTT. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analyse von Partikeleigenschaften beim Thermischen Spritzen von Mikropulvern

Analysis of In‐Flight Particle Properties of Thermal Sprayed Ultrafine Powders Demands on functional coatings with high dimensional accuracy and high surface quality has led to increasing interest in processing of very fine powder grades in a particle size range < 20 μm in past years. Fine powders are not only showing a distinct potential for application of thin and dimensionally accurate coatings, but are also very promising for the production of dense and homogeneous coatings with improved mechanical properties. The large specific surface of fine powders is allowing for relatively low thermal energy levels that are introduced into the process. Nevertheless is also requires a very sensitive temperature control, to prevent overheating of the particles. The reduction of the thermal energy level is resulting in significant advantages particularly for the usability of the HVOF process for coating of inner diameters. Within this work in‐flight particle properties of ultrafine carbide powders were analyzed. The studied HVOF process allows the adjustment of a broad parameter range by utilization of a hydrogen stabilized liquid fuel combustion process. A conventional straight nozzle type as well as a curved nozzle for internal spraying was studied. For a further assessment of the potential of ultrafine carbide powders also spray trials with a plasma spraying system have been made.     

Beständigkeit von Carbamid- und Phenolharzverleimungen bei Holzspanplatten

Zusammenfassung Das Verhalten von Holzspanplatten gegenüber Feuchtigkeitseinwirkung kann durch verschiedene Prüfverfahren erfa?t werden. Im allgemeinen wird hierfür die Dickenquellung nach DIN 52364 angewendet. Es bestehen Zweifel, ob mit einem Wasserlagerungsversuch im Sinne dieser Norm Rückschlüsse auf die Belastbarkeit bestimmter Plattentypen bei ihrer praktischen Anwendung gezogen werden k?nnen, wie es bisweilen geschieht. Die Bedingungen des Wasserlagerungsversuches im Hinblick auf einzelne Verleimungsarten werden er?rtert. Die Prüfung durch Lagerung in kochendem Wasser ist umstritten. Es mu? jedoch festgestellt werden, da? mit diesem Kurzzeitprüfverfahren gute Unterscheidungen zwischen den einzelnen Verleimungsarten und besonders hinsichtlich der Qualit?t von Phenolharzverleimungen getroffen werden k?nnen. Es besteht die Vermutung, da? zwischen der Witterungsbest?ndigkeit und der Best?ndigkeit gegen kochendes Wasser bei phenolharzverleimten Spanplatten ?hnlich wie beim Sperrholz bestimmte Beziehungen vorliegen. Bewitterungsversuche brachten bislang keine eindeutigen Ergebnisse. Dazu sind wahrscheinlich die bisherigen Versuchszeitr?ume zu kurz. Am geeingnetsten erscheinen Lagerungen unter Wechselklimaeinflu?. Hierfür ist die Erarbeitung entsprechender Lagerungsbedingungen im Hinblick auf die unterschiedlichen Kondensationsharze erforderlich.

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Investigations on the durability of gluing with carbamide and phenolic resins for wood particleboard

Summary The behaviour of wood particleboard against moisture can be determined by different test methods. In general, thickness swelling according to the German standard DIN 52364 is applied for this purpose. It is doubled whether a water-storage test according to this standard allows to draw conclusions on the strength of certain types of boards for their practical application, as is sometimes usual. The conditions of the water-storage test in regard to certain types of gluing are being discussed. The method of testing by storage in boiling water is controversional. However, it must be stated that by means of this short-term test method good possibilities of differentiation between the individual types of gluing and particularly with respect to the quality of phenolic-resin gluings are given. It is to be assumed that with phenolic-resin-glued particle-boards, similar to phywood, there are certain relations between the weathering resistance and the resistance against boiling water. Weathering tests sofar yielded no clear results, the past test periods probably having been too short. Storage under the influence of cycling climate appear to be most appropriate. This requires the preparation of corresponding storage conditions with respect to the different resin glues.