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321.
Taiwanese fishing boats have been hijacked many times this year. Trouble at sea can usually be attributed to communication problems, inappropriate management and an unfair salary system. The majority of boats hijacked are high sea (long-line) fishing boats. Although fishery authorities ask the fishing boats to set up vessel monitoring systems (VMSs), this precaution has not been sufficient. There is a further need for improved management by the fishing boat owner and for an improved employment policy for seamen. The issue of maritime security is not new, but it remains a major concern and continues to be a threat to Taiwan and other countries. To date, there have been many cases of hijacking in the South China Sea. This paper analyzes the reasons for the hijackings and provides potential strategies to prevent future incidents. 相似文献
322.
巷道围岩稳定性的判据及岩石分类 总被引:4,自引:0,他引:4
本文通过套筒致裂法测试巷道围岩应力及力学性质,并以此进行围岩稳定性分析和分类;提出了巷道围岩稳定性判据以及巷道围岩分类的原则;介绍了本稳定性分析方法在若干煤矿巷道围岩及立井井壁应力测试地点的应用。 相似文献
323.
324.
We study the distribution and transport of angular momentum in a self-gravitating accretion disk formed during the collapse of a rotating gas cloud. Using the surface density for the low-viscosity models and minimum-mass models presented by Cassen and Summers, Poisson's equation is solved explicitly to determine the effects of self-gravitation of the protostellar disk. Analytic expressions for the angular momentum of the central star and other relevant quantities of interest during the formation stage are presented.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.On leave from the City College of the City University of New York, U.S.A. 相似文献
325.
Three-dimensional, quasi-static evolutions of coronal magnetic fields driven by photospheric flux emergence are modeled by a class of analytic force-free magnetic fields. Our models relate commonly observed photospheric magnetic phenomena, such as the formation and growth of sunspots, the emergence of an X-type separator, and the collision and merging of sunspots, to the three-dimensional magnetic fields in the corona above. By tracking the evolution in terms of a continuous sequence of force-free states, we show that flux emergence and submergence along magnetic neutral lines in the photosphere are essential processes in all these photospheric phenomena. The analytic solutions we present have a parametric regime within which the magnetic energy attained by an evolving force-free field may be of the order of 1030 ergs to several 1031 ergs, depending on the magnetic environment into which an emerging flux intrudes. The commonly used indicators of magnetic shear in magnetogram interpretation are discussed in terms of field connectivity in our models. It is demonstrated that the crossing angle of the photospheric transverse magnetic field with the neutral line may not be a reliable indicator of the magnetic shear in the coronal field above, due to the complexity of three-dimensionality. The poorly understood constraint of magnetic-helicity conservation on the availability of magnetic free energy for a flare is briefly discussed.The National Center for Atmospheric Research is sponsored by the National Science Foundation. 相似文献
326.
A continuous reactor based on the fluidized bed technique was developed in order to study the kinetics and the mechanisms of the initial stages of weathering of albite. Simultaneous determination of Si, Al and Na and the observed low concentrations of the dissolved elements which were always at levels below saturation with respect to possible secondary precipitates, indicate that formation of a residual layer of a few tens of angstroms occurred at the surface of the feldspar. The composition of this layer, enriched in Si and/or Al, is strongly dependent on the pH of the aqueous solution. The formation of the layer is followed by the establishment of a quasi-steady state during which the dissolution of albite tends to become stoichiometric. 相似文献
327.
Characteristics of hydrolysis of the complex Na2SnF6 in hydrothermal solutions—An experimental study
Characteristics of hydrolysis of the complex Na2SnF6, which is used as the starting material, in hydrothermal solutions have been studied at 200–602°C and 1 kbar. Experimental
results show that intense hydrolysis of Na2SnF6 occurs at high temperatures and that with the rise of temperature the hydrolysis will become more intense. Under the present
experimental conditions the most possible existing form of Sn in the hydrothermal solutions is SnF3(OH) or Na2SnF3(OH). In addition, the hydrolysis constants for Na2SnF6 have also been calculated at 200–602°C, and the relationship between Na2SnF6 hydrolysis and temperature is discussed. 相似文献
328.
329.
Wave reflection and diffraction due to the presence of a detached breakwater are studied with the aid of directional wave fields. At first, experiments were carried out for the case where a breakwater is the sole factor affecting the wave field. It is shown that, estimated directional spectra in front of a detached breakwater can be separated into two parts in the spatial domain. Denoting these as the incident and reflected part of the total energy, an estimate of the reflection coefficient can be obtained. An empirical equation is proposed. This equation relates the reflection coefficients with the distances of the measuring stations away from the breakwater, as well as directionality of the wave field. This equation was then applied to the experiments where the fishing harbour Ba-Do-Zhi (BDZ) was used as model. It is shown that favorable results are obtained. On the other hand, diffraction due to the detached breakwater was also studied in a similar way. It is shown that predictions based on the empirical equation are in quantitative agreements with measurements. It is proposed that these empirical equations can be used in engineering applications. 相似文献
330.
海底光缆故障判定及测试方法 总被引:3,自引:0,他引:3
在海底光缆不可避免的发生故障后,准确、迅速地判断海底光缆故障情况,以及根据所获得的测试数据来确定故障点的位置,成为海底光缆修复流程中极其关键的步骤。介绍了海底光缆故障的几种类型,并针对不同的故障类型,根据其特性给出了相应的测试方法来判定故障点,从而为海底光缆发生故障后,迅速修复奠定了技术基础。 相似文献