Atomic layer deposition on biological macromolecules: metal oxide coating of tobacco mosaic virus and ferritin

Decoration of nanoparticles, in particular biomolecules, gathered high attention in recent years.(1-7) Of special interest is the potential use of biomolecules as templates for the fabrication of semiconducting or metallic nanostructures.(1-7,26) In this work we show the application of atomic layer deposition, a gas-phase thin film deposition process, to biological macromolecules, which are frequently used as templates in nanoscale science, and the possibility to fabricate metal oxide nanotubes and thin films with embedded biomolecules.(1-13).     

一种小型化频率综合器的设计

小型化是现代电子系统的一个重要的发展方向,频率综合器的小型化设计是射频系统小型化设计的重点之一。本文介绍了频率综合器小型化设计中的关键技术,难点以及解决的几种方法。     

Influence of laser wavelength on the critical energy density for initiation of energetic materials

Critical densities of the energy of laser initiation of PETN containing nanoscale aluminum inclusions at radiation wavelengths of 1064 and 532 nm were measured experimentally. The critical initiation-energy density that corresponds to a 50%th probability of explosion was 1.15 J/cm² for the first harmonic of a neodymium laser and 0.7 J/cm² for the second. The dependence of the efficiency of radiation absorption by aluminum on the size of metal nanoparticles for the first and second harmonics of a neodymium laser is calculated. It is shown that the particle diameter corresponding to the absorption efficiency maximum and the amplitude of the maximum depend on the radiation wavelength. The absorption efficiency maximum for the first harmonic is observed in an inclusion 204 nm in diameter, and for the second, in an inclusion 96 nm in diameter. The amplitude of the maximum increases from 0.351 at a wavelength of 1064 nm to 0.490 at a wavelength of 532 nm. Dependences of the critical initiation energy density for energetic materials on the radius of metallic nanoparticles are calculated. Qualitative agreement between theoretical and experimental results is shown.     

Control of substrate surface temperature in millisecond annealing technique using thermal plasma jet

Temporal variations of substrate surface temperature in scanning Ar thermal plasma jet has been investigated based on an analysis of transient changes in optical reflectivity. The accuracy of the temperature measurement has been evaluated to be 30 K at temperature around 1760 K. The maximum surface temperature (T_max) is controlled in the range from ∼ 960 to ∼ 1780 K with keeping the annealing duration (t_a) around ∼ 3 ms by changing the Ar gas flow rate (f) and distance between the plasma jet and the substrate (d) under a constant scanning speed (ν) of 500 mm/s.     

Structure and properties of orption-active nanocomposites from ultrahigh-molecular-weight polyethylene

The pore structure of filled films of ultrahigh-molecular-weight polyethylene fabricated by gel technology was investigated by IR spectroscopy and optical microscopy. The sorption capacity of films containing nanoparticles of zeolite and montmorillonite with respect to alkali and alkaline-earth metals was determined as a function of the degree of filling. __________ Translated from Khimicheskie Volokna, No. 2, pp. 33–37, March–April, 2007.     

The performance of the adaptive EWMA median chart in the presence of measurement error

In quality control applications, the control chart is a powerful tool but its performance is adversely affected by the contamination from either the inspector or the measuring device leading to measurement errors. In this paper, we investigate the performance of the AEWMA median chart with measurement errors, and a methodology is proposed to obtain the optimal parameters by considering a linearly covariate error model. Several figures and tables show that, with the existence of measurement errors, the efficiency of the AEWMA median chart can be strongly affected, but this negative effect can be compensated by taking multiple measurements at each sample point. Comparisons with the Shewhart and the classical EWMA schemes confirm the superiority of the AEWMA scheme for detecting a wide range of shifts in the case of precise and imprecise data. An example is provided to illustrate the use of the AEWMA median chart with measurement errors.     

Scenario-based requirements analysis techniques for real-time software systems: a comparative evaluation

One of the most critical phases of software engineering is requirements elicitation and analysis. Success in a software project is influenced by the quality of requirements and their associated analysis since their outputs contribute to higher level design and verification decisions. Real-time software systems are event driven and contain temporal and resource limitation constraints. Natural-language-based specification and analysis of such systems are then limited to identifying functional and non-functional elements only. In order to design an architecture, or to be able to test and verify these systems, a comprehensive understanding of dependencies, concurrency, response times, and resource usage are necessary. Scenario-based analysis techniques provide a way to decompose requirements to understand the said attributes of real-time systems. However they are in themselves inadequate for providing support for all real-time attributes. This paper discusses and evaluates the suitability of certain scenario-based models in a real-time software environment and then proposes an approach, called timed automata, that constructs a formalised view of scenarios that generate timed specifications. This approach represents the operational view of scenarios with the support of a formal representation that is needed for real-time systems. Our results indicate that models with notations and semantic support for representing temporal and resource usage of scenario provide a better analysis domain.H. Saiedian is a member of the Information & Telecommunication Technology Center at the University of Kansas. His research was partially supported by a grant from the National Science Foundation (NSF).     

Fibre materials based on ultrahigh-molecular-weight polyethylene and montmorillonite nanoparticles

The effect of the thermodynamic quality of the solvent on the properties of polymer solutions was determined. Thermal annealing affects formation of the structure and the mechanical properties of UHMPE. Fourier transform IR spectroscopy revealed the effect of the filler on the structure of the polymer matrix. The morphology of filled UHMPE fibres was characterized by optical microscopy; the fibres have a longitudinally oriented structure and the filler aggregates in particles up to 50 μm in size, which does not allow classifying the materials obtained as nanocomposites. Translated from Khimicheskie Volokna, No. 3, pp. 4–8, May–June, 2008.     

Suspension "hypokinesia/hypodynamia" may decrease bone mass by stimulating osteoclast production in ovariectomized mice

The factorial structure of the Beck Hopelessness Scale (BHS; A. T. Beck, A. Weissman, D. Lester, & L. Trexler, 1974) was examined in a nonclinical sample (N = 154) in Japan, and the relationships between dimensions of hopelessness and psychosocial variables were analyzed. A semistructured interview was used, as well as a questionnaire consisting of the BHS, the Eysenck Personality Questionnaire (EPQ; H. J. Eysenck & S. B. Eysenck, 1975), and the Parental Bonding Instrument (PBI; G. Parker, H. Tupling, & L. B. Brown, 1979). A factor analysis with principal components solution after oblimin rotation yielded 2 factors--Doubt About a Hopeful Future (Factor 1) and Belief About a Hopeless Future (Factor 2). Significant, positive correlations were found between Factor 2 and (a) the number of emotional symptoms of depression in a 4-day depressive episode and (b) scores on the Neuroticism subscale of the EPQ. The Factor 1 score was significantly and negatively correlated with the Extraversion subscale of the EPQ and the Paternal Care subscale of the PBI.     

在纯镁上激光熔覆镁铝合金层提高表面的耐蚀性

研究了在纯镁基底上用激光熔覆的镁铝合金A的显微组织,物相结构及腐蚀行为,表明该合金的组成相为α-Al和β-Mg_2Al_3,在界面上则生成了共晶层;合金内生成了多晶结构;合金的腐蚀速率比纯镁低两个数量级。