正确认识立体声,杜比环绕声,THX及AC—3——发烧纵横谈之三

正确认识李瑞麟立体声、杜比环绕声、ＴＨＸ及ＡＣ３———发烧纵横谈之三一些朋友常常问我，现在杜比环绕、ＴＨＸ和ＡＣ３一个接一个出来了，是否立体声（包括ＨｉＦｉ立体声）落后了或者应该被淘汰了？我告诉他们，立体声是声学处理的基础，立体声、杜比环绕、Ｔ...     

Determination of calibration constants for the hole-drilling residual stress measurement technique applied to orthotropic composites—Part I: Theoretical considerations

The hole-drilling technique for the measurement of residual stresses using electrical resistance strain gages has been widely used for isotropic materials and has been adopted by the ASTM as a standard method. A few attempts have been made to extend the technique to orthotropic composite materials. For thin isotropic plates, with a hole drilled through the thickness, the idealized hole-drilling calibration constants are obtained by making use of the well known Kirsch's solution. In this paper, an analogous attempt is made to theoretically determine the three idealized hole-drilling calibration constants for thin orthotropic materials by employing Savin's complex stress function approach. In Part II (to appear in the next issue), test results for a graphite-polyimide composite, with a very high degree of orthotropy, are given and compared with the theoretical results.     

Determination of calibration constants for the hole-drilling residual stress measurement technique applied to orthotropic composites—Part II: Experimental evaluations

The semi-destructive hole-drilling technique for measuring residual stresses is well established for isotropic materials and a few attempts have been made to extend this method to orthotropic composite materials. The first step in such an extension is the determination of the three calibration constants. In Part I of this investigation (pp. 105–118 of the previous issue) a theoretical determination of the calibration constants based on Savin's analysis, analogous to the procedure for isotropic materials based on Kirsch's solution, was described. Here, an experimental determination of these calibration constants for a highly orthotropic unidirectionally reinforced graphite-polyimide composite is described. The experimentally determined values are compared with the theoretical values.     

Renewable energy research 1995–2009: a case study of wind power research in EU, Spain, Germany and Denmark

The paper reports the developments and citation patterns over three time periods of research on Renewable Energy generation and Wind Power 1995–2011 in EU, Spain, Germany and Denmark. Analyses are based on Web of Science and incorporate journal articles as well as conference proceeding papers. Scientometric indicators include publication collaboration ratios, top-player distribution as well as citedness and correspondence analyses of citing publications, relative citation impact, distributions of top-cited as well as top-citing institutions and publication sources and cluster analysis of citing title terms to map knowledge export areas. Findings show an increase in citation impact for Renewable Energy and Wind Power research albeit hampered by scarcely cited conference papers. Although EU maintains its global top position in producing Renewable Energy and Wind Power research the developments of EU and German world shares as well as citation impact are negative during the most recent 7 year period. During the same time the citation impact of Spain and Denmark increase and place both nations among the top-ranking countries in Wind Power research. Spain is the only EU country that increases its world production share from 2000. China is currently ranked three after EU and USA in research output, however with a very low citation impact. Spain, Denmark and Germany each demonstrates distinct collaboration patterns and publication source and citation distribution profiles. More than half the citations to EU Wind Power research are EU-self citations. An expected intensified EU collaboration in the Wind Energy field does not come about. The most productive research institutions in Denmark and Spain are also the most cited ones.     

The zeta-potential measurement for concentrated aqueous suspension by improved electrophoretic mass transport apparatus — application to Al2O3, ZrO3 and SiC suspensions

The zeta-potentials for Al₂O₃, ZrO₂ and SiC particles in concentrated suspensions were determined by an improved mass transport apparatus in order to obtain reliable and reproducible data on particle dispersion in the slip casting process. The values of isoelectric point for each particle were as follows: pH 8 for Al₂O₃, 5 for monoclinic ZrO₂, 6.5 for tetragonal ZrO₂, 4 for -SiC and 5.5 for -SiC. It was suggested that the values of zetapotentials for those particles were affected by the chemical and physical state of the particle surfaces, i.e. crystal structure, comtamination and hydration, etc. The apparatus used in this experiment will be also available for use with suspensions containing surfactants in practical slip casting.