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We describe the design and operation of a critically phase-matched femtosecond optical parametric oscillator based on KTA. By employing a small pump-signal noncollinear angle, tuning of the idler to beyond 4 μm is achieved using a Ti:sapphire pump laser. A Gaussian-beam model is described which can be used to identify the optimal noncollinear phase-matching geometry. Idler and signal pulses are characterized fully both temporally and spectrally and interferometric autocorrelation data at 3.5 μm showing idler pulses of only eight optical cycles duration are presented  相似文献   
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The results of a retrospective study of routine measurement of haemoglobin at the examination of one-year-old children at Gr?land mother and child clinic during 1989-91 showed that 37% of the children had anaemia. There was no difference between immigrants and the European population. There was no correlation between anaemia and sex in either of the population groups. This may imply that routine haemoglobin measurement should be generally introduced as part of the regular control of one-year-old children.  相似文献   
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Forensic psychology has made important gains in professional recognition and stature in the courts, resulting in increasing demands for mobility of expertise. Current regulations regarding the interjurisdictional temporary forensic practice of psychology, however, are characterized by variability of regulations, ambiguity and inaccessibility, and continuing total barriers. A uniform, well-reasoned policy is needed. A conceptual basis for such a policy is provided by a discussion of licensing rationales and the application of these to forensic practice. Uniformity, public and professional protection, and practicability are identified as fundamental regulatory criteria. A Model Rule Regarding the Temporary Forensic Practice of Psychology is proposed for adoption by state licensing boards on a nationwide basis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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RoryReid 《个人电脑》2004,10(11):73-73
如果问一位资深的游戏玩家:图像和游戏本身哪个更重要?他们一般会选后者。既然这样.为什么整个图形行业还在步调一致地开发新的图形技术。  相似文献   
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Analytical ultracentrifugation is commonly used for the determination of molecular weights (sedimentation equilibrium) and sedimentation coefficients (sedimentation rate) of biological macromolecules in solution. A Turbo Pascal program for the analysis of sedimentation equilibrium centrifugation data produced by absorbance optical systems is described. The user may enter data from a scan of absorbance versus distance from the centre of rotation, via a graphics tablet (or ASCII file). This is subsequently manipulated to yield an apparent weight average molecular weight for the given sample. Plots of ln (absorbance) versus (radius2) may also be produced. The method described uses readily available computational equipment requiring only a graphics tablet in addition to an IBM PC compatible computer. This technique and the software developed have been used to investigate the molecular weight range of two International Humic Substances Society (IHSS) reference samples from the Suwannee River.  相似文献   
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As a step towards the construction of a comprehensive model for damaged composites, the deformation of transversely cracked laminates is analysed. The approach is based on a generalised plane strain approach and uses the finite strip method which allows general lay-ups of laminates rather than just cross-ply to be considered. General loading is treated. In addition, the method permits a more flexible control to be exercised between accuracy and the extensiveness of the calculations than can be achieved using existing analyses. This method could be integrated with the finite element analysis of structures to allow for changes in the effective material properties of locally damaged regions. Results produced by the approach are compared with those available in the literature and good agreement is demonstrated.  相似文献   
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Rates of poor psychological adjustment of children with sickle cell disease remained relatively constant over initial and follow-up assessment points. 50 children (aged 7–12 yrs) and their mothers completed the initial protocol. 30 children completed the follow-up plus 5 additional children and their mothers. These Ss were aged 7–24 yrs at follow-up. With initial levels of adjustment controlled, children's strategies for coping with pain accounted for a significant increment in child-reported symptoms and mother-reported internalizing behavior problems at follow-up beyond the contribution of illness and demographic parameters and follow-up interval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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