Growth of Dense Single Crystals of Potassium Sodium Niobate by a Combination of Solid-State Crystal Growth and Hot Pressing

(K_0.5Na_0.5)NbO₃ (KNN) is a potential lead-free replacement for Pb(Zr, Ti)O₃ (PZT) piezoceramics, but its piezoelectric properties are inferior to those of PZT. By growing single crystals of KNN, it may be possible to improve the piezoelectric properties. Recently, single crystals of KNN were grown by the solid-state crystal growth (SSCG) method, but the crystals were very porous. In this paper, a method of growing dense single crystals by SSCG in a hot press will be described. (110)-oriented single seed crystals of KTaO₃ were buried in KNN powder, with 0.5 mol% of K₄CuNb₈O₂₃ added as a sintering aid. After consolidation by uniaxial and isostatic pressing, the tablets were hot pressed in a two-stage treatment. During hot pressing, dense single crystals of KNN grew using the KTaO₃ seed crystal as a template. The effect of hot pressing on single crystal growth will be discussed.     

Are biomarkers of chronic alcohol misuse useful in the assessment of DWI recidivism status?

A first driving while impaired by alcohol (DWI) conviction is a key opportunity to identify offenders who are at high risk for recidivism. Detection of alcohol use disorder (AUD) is a major target of current DWI assessments. However, offenders frequently underreport their alcohol consumption, and use of biomarkers has been proposed as a more objective indicator. Among the best established are aspartate aminotranferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), mean corpuscular red blood cell volume (MCV), carbohydrate-deficient transferrin (CDT), and thiamine. To our knowledge, no research has directly verified whether AUD biomarkers predict DWI recidivism status. Using a cross-sectional design, this study tested three hypotheses related to the utility of biomarkers in DWI assessment.

Hypotheses

(1) DWI recidivists possess biomarkers indicative of greater prevalence of AUD compared to first-time offenders; (2) multiple biomarkers better differentiate first-time offenders from recidivists compared to individual biomarkers; and (3) biomarkers add significantly to the prediction of recidivism over and above psychosocial questionnaires.

Methods

First-time offenders (n = 49) and recidivists (n = 95) participated in the study. In addition to self-reported information on sociodemographic and driving characteristics, data from several AUD questionnaires were gathered: Michigan Alcoholism Screening Test, Alcohol Use Disorders Identification Test, Composite International Diagnostic Interview, and Timeline Follow-Back. Blood samples were collected to measure AST, ALT, GGT, MCV, CDT, and thiamine.

Results

AUD biomarkers, taken individually or in combination, did not indicate that recidivists had more frequent AUD compared to first-time offenders. Also, they failed to significantly differentiate first-time offenders from recidivists or predict recidivism status. Finally, the superiority of biomarkers over psychosocial AUD questionnaires was not supported in the laboratory setting.

Conclusion

The present findings suggest that biomarkers of chronic patterns of heavy drinking may not be adequate to capture the multiple processes that appear to promote recidivism (e.g., binge drinking, other risky behavioural and personality features). Despite their objectivity, caution is warranted in the interpretation of a positive score on these biomarkers in DWI assessment. Longitudinal research is needed to more comprehensively explore the relationship between positive biomarkers in first-time offenders and their risk of becoming recidivists.     

A Taxonomy of Spatial Data Integrity Constraints

Spatial data quality has become an issue of increasing concern to researchers and practitioners in the field of Spatial Information Systems (SIS). Clearly the results of any spatial analysis are only as good as the data on which it is based. There are a number of significant areas for data quality research in SIS. These include topological consistency; consistency between spatial and attribute data; and consistency between spatial objects representation and their true representation on the ground. The last category may be subdivided into spatial accuracy and attribute accuracy. One approach to improving data quality is the imposition of constraints upon data entered into the database. This paper presents a taxonomy of integrity constraints as they apply to spatial database systems. Taking a cross disciplinary approach it aims to clarify some of the terms used in the database and SIS fields for data integrity management. An overview of spatial data quality concerns is given and each type of constraint is assessed regarding its approach to addressing these concerns. Some indication of an implementation method is also given for each.     

State feedback design for input-saturating quadratic systems

This paper proposes a method to design stabilizing state feedback control laws for nonlinear quadratic systems subject to input saturation. Based on a quadratic Lyapunov function, a modified sector condition and a particular representation for the quadratic terms, synthesis conditions in a “quasi”-LMI form are stated in a regional (local) context. An LMI-based optimization problem is then derived for computing the state feedback gains maximizing the estimate of the stability region of the closed-loop system.     

Kolmogorov complexity and combinatorial methods in communication complexity

We introduce a method based on Kolmogorov complexity to prove lower bounds on communication complexity. The intuition behind our technique is close to information theoretic methods.We use Kolmogorov complexity for three different things: first, to give a general lower bound in terms of Kolmogorov mutual information; second, to prove an alternative to Yao’s minmax principle based on Kolmogorov complexity; and finally, to identify hard inputs.We show that our method implies the rectangle and corruption bounds, known to be closely related to the subdistribution bound. We apply our method to the hidden matching problem, a relation introduced to prove an exponential gap between quantum and classical communication. We then show that our method generalizes the VC dimension and shatter coefficient lower bounds. Finally, we compare one-way communication and simultaneous communication in the case of distributional communication complexity and improve the previous known result.     

StarPro 2000型DSP的体系结构和特性

随着无线和有线网络逐步从话音和低速数据领域转移到高速多媒体应用,以及电路交换网络和分组交换网络的融合,OEM设计者发现自己面临着一些令人困惑、互相冲突的约束.一方面要求他们能够迅速捕捉越来越细化的市场机会,与此同时还要使其设计同时满足目前和未来的需求.     

Mixed Lubrication with C18 Fatty Acids: Effect of Unsaturation

In this paper, the lubrication mechanism of fatty acids is revisited with a new approach combining experimental and computational chemistry studies. The lubricating properties of single and mixtures of stearic, oleic and linoleic acids in a synthetic Poly-Alpha-Olefin base oil (PAO4) on iron oxide surface are investigated under mixed boundary regime with temperatures from 50 °C up to 150 °C. Low friction coefficient (about 0.055) with no visible wear is reported in the presence of single stearic acid at high temperature. This lubricating behavior is inhibited in the presence of unsaturated fatty acids highlighting an anti-synergic effect of a saturated/unsaturated mixture, especially at 150 °C. To understand the anti-synergic effect and the adsorption mechanism of these molecules, molecular dynamic (MD) and quantum chemistry simulations are performed to evaluate their diffusion coefficient in PAO4 and their adsorption mechanism on iron oxide at different temperatures. MD simulation results show a faster diffusion toward the surface for unsaturated fatty acids than for saturated fatty acid at all the studied temperatures. This means that unsaturated molecules arrive and mainly adsorb before stearic acid on the surface leading to a tribological behavior of the mixture characteristic of the unsaturated molecule. Computational chemistry suggests that all fatty acids (saturated and unsaturated) adsorption mechanism is due to the chemisorption of the carboxylic group on iron oxide surface with no desorption up to 150 °C.