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131.
煤层气井有杆排采系统悬点动载荷计算 总被引:1,自引:0,他引:1
有杆泵排采设备悬点动载荷是正确设计和选择抽油机和抽油杆以及确定电动机功率的重要影响因素。在分析杆柱和液柱受力状态的基础上,建立了惯性载荷的数学模型,基于弹性体振动理论,建立了振动载荷的计算模型,并给出悬点动载荷的计算方法和变化规律。结果表明,煤层气井悬点载荷的计算需同时考虑惯性载荷和振动载荷,且开采初期,动载荷所占比重较大;随着开采的进行,动载荷所占比重迅速减小,稳定生产时,影响已较小;杆管总变形量明显小于油田,且动变形量相对较小。该算法首次较为精确地计算出煤层气井有杆排采系统的悬点载荷并给出示功图,为有杆排采的设计计算提供了依据。 相似文献
132.
介绍了150SBD-12型离心式砂石泵轴端密封的结构原理和相应的技术措施,双浮动密封装置成功地取代了传统的填料密封,并取得了良好的使用效果。 相似文献
133.
治理地下水有机污染抽出处理技术影响因素分析 总被引:7,自引:1,他引:6
吴玉成 《水文地质工程地质》1998,25(1):27-29,42
抽出处理技术是治理地下水有机污染简便易行的方法,文中的简要介绍抽出处理方法去除污染机制之后,着重分析了讨论了导致该方法去除地下水有机污染耗时及运行费用高昂的原因,在此基础上,对地下水有机污染抽出处理技术作出全面详尽的评述。 相似文献
134.
135.
单片机在程控加油机中的开发与应用 总被引:1,自引:0,他引:1
介绍一种以8031为CPU的智能化防爆程控加油机系统,且有计量精度高的特点。可广泛应用于石油、化工等防爆场合。 相似文献
136.
Numerical flow simulation of flush type intake duct of waterjet 总被引:1,自引:0,他引:1
Waterjet propulsion system is widely used to thrust high speed marine vessels in excess of 30–35 knots by virtue of high propulsive efficiency, good maneuverability, and less vibration. Since, however, approximately 7–9% of the total power is lost in intake duct due to flow separation, nonuniformity, etc., detail understanding of flow phenomena occurring within intake duct is essential to reduce the power loss. The present work solved 3D incompressible RANS equations on multiblocked grid system of the flush type intake duct of waterjet. The numerical results of surface pressure distributions, velocity vectors, and streamlines were compared with experiments and good agreements were obtained for three jet velocity ratios. Strong suction flow through the inlet was shown and the vortex induced by the separation along the corner of the side wall was clearly shown. Flow separation on the lip was also observed. The location of stagnation point on the lip was well predicted, in accordance with PIV measurement. 相似文献
137.
Ulf Riebesell 《Journal of Oceanography》2004,60(4):719-729
Rising atmospheric CO2 and deliberate CO2 sequestration in the ocean change seawater carbonate chemistry in a similar way, lowering seawater pH, carbonate ion concentration
and carbonate saturation state and increasing dissolved CO2 concentration. These changes affect marine plankton in various ways. On the organismal level, a moderate increase in CO2 facilitates photosynthetic carbon fixation of some phytoplankton groups. It also enhances the release of dissolved carbohydrates,
most notably during the decline of nutrient-limited phytoplankton blooms. A decrease in the carbonate saturation state represses
biogenic calcification of the predominant marine calcifying organisms, foraminifera and coccolithophorids. On the ecosystem
level these responses influence phytoplankton species composition and succession, favouring algal species which predominantly
rely on CO2 utilization. Increased phytoplankton exudation promotes particle aggregation and marine snow formation, enhancing the vertical
flux of biogenic material. A decrease in calcification may affect the competitive advantage of calcifying organisms, with
possible impacts on their distribution and abundance. On the biogeochemical level, biological responses to CO2 enrichment and the related changes in carbonate chemistry can strongly alter the cycling of carbon and other bio-active elements
in the ocean. Both decreasing calcification and enhanced carbon overproduction due to release of extracellular carbohydrates
have the potential to increase the CO2 storage capacity of the ocean. Although the significance of such biological responses to CO2 enrichment becomes increasingly evident, our ability to make reliable predictions of their future developments and to quantify
their potential ecological and biogeochemical impacts is still in its infancy.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
138.
Atsushi Yamaguchi Yuji Watanabe Hiroshi Ishida Takashi Harimoto Kazushi Furusawa Shinya Suzuki Joji Ishizaka Tsutomu Ikeda Masayuki Mac Takahashi 《Journal of Oceanography》2004,60(4):773-787
As part of the research program WEST-COSMIC Phase I (1997–2001), vertical profiles down to the greater depths (0–2000 m or
5800 m) of the plankton community structure composed of heterotrophic bacteria, phytoplankton, protozooplankton and metazooplankton
were studied at one station in each subarctic (44°N) and in transitional region (39°N), and two stations in subtropical region
(30°N and 25°N); all in 137–155°E in the western North Pacific Ocean. The biomass of all four taxonomic groups decreased rapidly
with increasing depths at all stations, although the magnitude of depth-related decrease differed among the groups. As plankton
community structure, metazooplankton biomass and bacterial biomass occupied >50% of the total in 0–2000 and 2000–4000 or 5000
m strata, respectively, at subarctic and transitional stations, while bacterial biomass contributed to >50% of the total consistently
from 0 through 4800 or 5800 m at subtropical stations. Metazooplankton biomass integrated over the greater depths exhibited
a clear latitudinal pattern (high north and low south), but this was not the case for those of the other taxonomic groups.
As a component of metazooplankton, an appreciable contribution of diapausing copepods to the metazooplankton was noted at
subarctic and transitional stations, but they were few or nil at subtropical stations. As protozooplankton assemblages, heterotrophic
microflagellates (HMF) and dinoflagellates were two major components at subarctic and transitional stations, but were only
HMF predominated at subtropical stations. From biomass ratios between heterotrophic bacteria, HMF and dinoflagellates, “sinking
POC-DOC-heterotrophic bacteria-HMF-heterotrophic dinoflagellates” link was proposed as a microbial food chain operative in
the deep layer of the western North Pacific. All results are discussed in the light of latitudinal differences in the structure
and functioning of plankton community contributing to the ‘biological pump’ in the western North Pacific Ocean.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
139.
断层带中超压流体及其在地震和成矿中的作用 总被引:14,自引:0,他引:14
地震断层带中的局部存在对其力学和化学过程有着重要影响的超压流体,对这种超压流本的证据。超压机制及其在地震活动和成矿中的作用等进行了探讨。流体超压是在断层带中渗透性的构造发生强烈时空变化的前提下产生的,其主要原因是构造加压及深源高压流体的注入,当流体压力升至一临界值时,断层发生灾难性破裂,即地震,增加断层的渗透性,超压流体快速向低压带(室或域)流动,同时因减压流体所携载水溶物各(包括成矿物质)大量沉淀析出,降低断层带的渗透性,地震泵吸和流体超压机制的交替作用使得这一过程得以周期性地进行。 相似文献
140.