有序熔楔和转捩

本文研究烧蚀表面上的一种尖楔状沟槽,简称熔楔。实验表明,熔楔是边界层转捩区的一种烧蚀现象;在蜂蜡和一些高温材料的球头上,熔楔排列有序,形成规则图象。在所实验的参数范围内,熔楔的条数保持在20条左右,不随来流马赫数、球头半径和烧蚀材料类型不同而改变。在分析研究熔楔内部结构和外流条件的基础上,本文提出熔楔形成机理和内外流动模型的设想,并对熔楔的形态、分布以及由它引导出菱形花纹等现象作了解释。

Free surface vibration in oscillatory convection of half floating zone

Projecting an orthographical grating mask (20pl/mm) on the surface of a small liquid bridge and receiving the reflected distortion image, one can calculate out reversely the shape of free surface of a liquid bridge. In this way we measured the surface shape of a small floating zone and the two-dimensional deformation of its vibration. The mechanism of thermocapillary oscillatory convection and the three-dimensional variation of the free surface are revealed experimentally. The principle for space experiment has been studied in our laboratory.

五轴框架式机器人激光加工系统轨迹算法研究

在集成化智能激光加工系统工作原理的基础上提出了五轴机器人的激光加工轨迹算法。将三维离散数据点集拟合为空间参数曲面，在此参数曲面上规划五轴激光加工的等距轨迹。给出了冲压模具激光强化加工实例，取得了理想的加工效果。

Collecção das Leis do Imperio do Brasil de 1848

Parte 1 - Leis

EQUIVALENT MODEL OF EXPANSION OF CEMENT MORTAR UNDER SULPHATE EROSION

The expansion property of cement mortar under the attack of sulfate ions is studied by experimental and theoretical methods. First, cement mortars are fabricated with the ratio of water to cement of 0.4, 0.6, and 0.8. Secondly, the expansion of specimen immerged in sulphate solution is measured at different times. Thirdly, a theoretical model of expansion of cement mortar under sulphate erosion is suggested by virtue of represent volume element method. In this model, the damage evolution due to the interaction between delayed ettringite and cement mortar is taken into account. Finally, the numerical calculation is performed. The numerical and experimental results indicate that the model perfectly describes the expansion of the cement mortar.

Euskal itzulpengintzaren eta interpretazioaren ikerketa-bideak: laborategi erraldioa

Raquel Merino Álvarez, José Miguel Santamaría, Eterio Pajares (eds.)

Recent changes in the efficiency of vessels fishing for yellowfin tuna in the eastern Pacific Ocean

ENGLISH: Since the inception of the Inter-American Tropical Tuna Commission in 1950, one of the primary tasks of its scientific staff has been the collection and analysis of the statistics of total catch, effort expended in obtaining this catch, and the apparent abundance of yellowfin tuna (Neothunnus macropterus) and the skipjack tuna (Katsuwonus pelamis) in the Eastern Pacific Ocean. A concentrated effort by the staff during 1951 and 1952 resulted in the compilation of a series of historical data on the catch and catch-per-effort of tropical tunas for the years 1934-1950, and in the establishment of a detailed logbook system to monitor the current activities of the tuna fleets. Schaefer (1953) and Shimada and Schaefer (1956) have reviewed in detail the methods of collection and analysis of these data. Further studies, based on these and subsequently collected records, are contained in publications by Schaefer (1957), Shimada (1958), Alverson (1959, 1960), Griffiths (1960) and Calkins (1961). SPANISH: Desde que la Comisión Interamericana del Atún Tropical comenzó sus funciones en 1950, entre las más importantes tareas de su personal científico incluyó la recolección y análisis de las estadísticas de la captura total, del esfuerzo empleado en obtener esta captura y de la abundancia aparente de los atunes aleta amarilla (Neothunnus macropterus) y barriletes (Katsutvonus pelamis) en el Océano Pacífico Oriental. El concentrado esfuerzo del personal científico de la Comisión durante 1951 y 1952 dió como resultado la compilación de una serie de datos históricos sobre la captura de atunes tropicales y sobre la captura según el esfuerzo durante los años 1934 a 1950, así como el establecimiento de un sistema detallado de registro de las anotaciones en los cuadernos de bitácora para vigilar las actividades diarias de las flotas atuneras. Schaefer (1953) y Shimada y Schaefer (1956) han expuesto detalladamente los métodos de recolección y análisis de dichos datos. Otros estudios, basados en estos registros y en los recolectados posteriormente, se encuentran en las publicaciones de Schaefer (1957), Shimada (1958), Alverson (1959, 1960), Griffiths (1960) y Calkins (1961).

Algas verdes en el picoplancton y nanoplancton del estuario del río Nervión (Golfo de Vizcaya)

332 p. : il., gráf.

Synopse dos trabalhos da Camara dos Srs. Deputados : relativos ao anno de 1923 : acompanhados de differentes documentos : organizada na Secretaria da mesma Camara

Sinopse dos trabalhos na Câmara dos Deputados, em 1923.

Deformation Of Pdms Membrane And Microcantilever By A Water Droplet: Comparison Between Mooney-Rivlin And Linear Elastic Constitutive Models

In this paper, we studied the role of vertical component Of Surface tension of a water droplet on the deformation of membranes and microcantilevers (MCLs) widely used in lab-on-a-chip and micro-and nano-electromechanical system (MEMS/NEMS). Firstly, a membrane made of a rubber-like material, poly(dimethylsiloxane) (PDMS), was considered. The deformation was investigated using the Mooney-Rivlin (MR) model and the linear elastic constitutive relation, respectively. By comparison between the numerical solutions with two different models, we found that the simple linear elastic model is accurate enough to describe such kind of problem, which would be quite convenient for engineering applications. Furthermore, based on small-deflection beam theory, the effect of a liquid droplet on the deflection of a MCL was also studied. The free-end deflection of the MCL was investigated by considering different cases like a cylindrical droplet, a spherical droplet centered on the MCL and a spherical droplet arbitrarily positioned on the MCL. Numerical simulations demonstrated that the deflection might not be neglected, and showed good agreement with our theoretical analyses. (C) 2008 Elsevier Inc. All rights reserved.