纳米科学和技术的二次浪潮

在过去的十年里纳米科学的首次浪潮澎湃而过。在此期间,国际、国内以及香港的学者已向世人证实他们可以采用“build-up”或“build-down”的办法制造大量的纳米管,纳米线以及纳米团簇,这些努力已经表明,如果纳米结构能够低廉地制造,那我们就会有更丰硕的收获。尺度小于20纳米的结构会展现非经典的性质,这提供给我们一个用全新的想法来制造功能器件的基础。在半导体工业,制造结构尺寸小于70纳米器件的能力允许器件的持续微型化。在下一个10年中,纳米科学和技术的另一次浪潮将可能来临,在这个新时期,科学家和工程师需要展示人们对纳米结构的期待功能以及证实他们的进一步的潜力,拥有在纳米结构实际器件的尺寸、组份,有序和纯度上的良好控制能力将实现人们期望的功能,在本文中,我们将讨论纳米科学和技术在新时期里发展所面对的困难和挑战。一系列新的方法将被讨论。我们还将讨论倘若这些困难能够被克服我们可能会有的收获。     

高强度聚焦超声(HIFU)的声场检测

针对高强度聚焦超声（HIFU）声场的特点，对高强度聚焦超声（HIFU）声场检测的方法如，辐射压力法、水听器测量法、光纤检测和光学检测进行了综述，并对上述检测方法进行了比较。     

After Boyle and the Leviathan: the Second Generation of British Air Pumps

This paper examines the second generation of British air pumps, covering the period 1700–1750. The air pump originated in the 1650s and 1660s thanks to the work of Otto von Guericke in Magdeburg, Robert Boyle in Oxford and London, and Accademia del Cimento in Florence. While these first models were often seen as unreliable and temperamental, and available to a small group only, the next period saw the air pump transformed into a publicly accessible device for use in public and private demonstrations, in practical applications, as well as in the production of new knowledge. In England, the instrument maker Francis Hauksbee and his followers played a decisive role in this process, which was connected, among other things, to popular medicine, anatomy and health. In this period, pneumatics (the field of air pumps and air-pump practice) reached a state where the pump came to be regarded as an unproblematic tool; and where a ‘vacuum’ came to be thought of and handled as an object.     

ATP determination with the Tricarb scintillation counter

Zusammenfassung Die Arbeit beschreibt eine neue Technik zur Bestimmung geringster Mengen von ATP (10–11 Mol und weniger) mit der Luciferin-Luciferase-Methode. Die dabei erzeugten Impulse werden mit einem Scintillationszähler gemessen.

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Aided by a generous donation from Mrs.D. Teperman, Canada, in memory of her late husband,Joseph Teperman.     

Forecasting the federal budget with time-series models

The stochastic properties of conventionally denned federal expenditures and revenues are examined, and cointegration is found. Alternative time-series models-univariate ARIMA models, vector autoregressions in levels and differences, and an error correction model-are specified and estimated using quarterly data from 1955:1 through 1979:4. Updated forecasts for up to three years beyond the sample period are evaluated against actual expenditures, revenues and the deficit. The vector autoregression in levels shows evidence of nonstationarity, which leads to strong biases in the forecasts. The remaining models produce forecasts that are satisfactory by the mean squared error criterion, and the magnitudes of biases at the longer horizons are significantly smaller than those of the official forecasts.     

Investigation of the circulation with fluorescent substances

Zusammenfassung Es wird eine neuartige Methode zum Studium der Blutzirkulation in derbem und weichem Gewebe beschrieben. Ein fluoreszierender Stoff wurde intravenös injiziert, das Präparat tiefgefroren, mit einem Hobel geglättet und dann photographiert.