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991.
992.
为了安全生产,矿井或采掘工作面瓦斯涌出量较大、采用通风方法解决瓦斯问题不合理时,应抽放瓦斯。瓦斯的抽放方法多种多样,具体采用哪一种方法或几种方法,应该具体问题具体分析。本文分析了芦岭煤矿Ⅱ1048工作面地面瓦斯抽放钻孔的抽排情况,得出如下结论:对于透气率极低的煤层,施工井下钻孔或地面压裂钻孔抽放效果往往不理想;首先开采适当的保护层,并有在开采之前施工地面钻孔抽放瓦斯是行之有效的。这种方法对于其它类似矿区,具有借鉴意义。 相似文献
993.
烃源岩有限空间温压共控生排烃模拟实验研究 总被引:13,自引:0,他引:13
烃源岩的生烃反应是在其限定的孔隙空间中承受高静岩压力和流体压力下进行的,然而受实验装置和条件的限制,目前大多数的生排烃模拟实验都是在一个低压、相对较大的生烃空间下进行的,与实际地质情况差异较大。通过对同一样品分别进行有限空间和常规高压釜方式加水模拟实验对比研究发现:(1)有限空间热压模拟实验的气态产物更接近地质实际。气体组分中烃气占有更大的比重;重烃气的保存下限大于常规模拟,延迟了重烃气向甲烷的转化;烯烃含量比常规加水模拟条件下更少,基本检测不到。(2)有限空间的限制使水介质参与成烃反应的作用增强,其限定空间内较高的流体压力延迟了油向烃气的转化过程,有利于液态油的生成和保存。(3)有限空间下高压液态水介质条件有利于烃类的排出。 相似文献
994.
《African Journal of Marine Science》2013,35(3):403-414
Seasonal fluctuations in the occurrence of inshore South African Bryde's whales Balaenoptera edeni were investigated between November 2005 and June 2008. Sighting data were collected in Plettenberg Bay on the south-east coast of South Africa. Bryde's whale occurrence was modelled in relation to the following environmental covariates: sea surface temperature, chlorophyll a concentrations and wind speed. Seasonal increases in encounter rates (sightings per day) were observed during summer and autumn, with a peak in April that corresponded to increased feeding activity and above average aggregation sizes. All three environmental covariates were significant factors in terms of explaining variability in the occurrence of whales. Multispecies associations with common dolphins Delphinus capensis and Cape gannets Morus capensis were most common in summer and autumn, when feeding activity was highest. 相似文献
995.
J.A. Moreno-Bedmar M. Company T. Bover-Arnal R. Salas G. Delanoy R. Martínez A. Grauges 《Cretaceous Research》2009,30(4):864-872
It is now generally accepted that the Oceanic Anoxic Event 1a [OAE 1a] correlates with the lower part of the Leupoldina cabri planktonic foraminiferal Zone. Its calibration against the standard ammonite scale, however, seems to be more problematic. This is due, in part, to the fact that ammonites are scarce and/or of little diagnostic value from a biochronological viewpoint in the lower Aptian pelagic successions where the black shale horizons are better developed.We have been able to characterize OAE 1a geochemically in the relatively shallow water deposits of the eastern Iberian Chain (Maestrat Basin, eastern Spain), where ammonite faunas are rich. The interval corresponding to this event is dominated by the genera Roloboceras and Megatyloceras, accompanied by Deshayesites forbesi and Deshayesites gr. euglyphus/spathi. This assemblage is characteristic of the middle/upper part of the Deshayesites weissi Zone. The first occurrence of the species Deshayesites deshayesi (d'Orbigny), which marks the base of the overlying zone, takes place in our sections some metres above the OAE 1a interval.In the historical stratotype region of Cassis-La Bédoule (southern Provence Basin, southeastern France), the OAE 1a interval is also characterized by the presence of Roloboceras and Megatyloceras. Nevertheless, it has usually been correlated with the D. deshayesi Zone. In our opinion, this discrepancy is due to divergences in the taxonomic assignments of the deshayesitids present in these beds. In fact, the specimens attributed by French authors [Ropolo, P., Conte, G., Gonnet, R., Masse, J.P., Moullade, M., 2000. Les faunes d'Ammonites du Barrémien supérieur/Aptien inférieur (Bédoulien) dans la région stratotypique de Cassis-La Bédoule (SE France): état des connaissances et propositions pour une zonation par Ammonites du Bédoulien-type. Géologie Méditerranéenne 25, 167–175; Ropolo, P., Moullade, M., Gonnet, R., Conte, G., Tronchetti, G., 2006. The Deshayesitidae Stoyanov, 1949 (Ammonoidea) of the Aptian historical stratotype region at Cassis-La Bédoule (SE France), Carnets de Géologie / Notebooks on Geology Memoir 2006/01, 1–46.] to D. deshayesi and D. dechyi can be reinterpreted as belonging to D. forbesi.Following this reinterpretation, the Roloboceras beds (equivalent of OAE 1a) of Cassis-La Bédoule would also correspond to the D. weissi Zone. This age is additionally corroborated by data from southern England [Casey, R., 1961a. The stratigraphical palaeontology of the Lower Greensand. Palaeontology 3, 487–621; Casey, R., 1961b. A Monograph of the Ammonoidea of the Lower Greensand, part III. Palaeontographical Society, London, pp. 119–216], and by our recent observations in Le Teil (Ardèche Platform, southeastern France), where the Roloboceras faunas are also associated with Deshayesites consobrinus and Deshayesites gr. euglyphus, taxa that are characteristic of the D. weissi Zone. 相似文献
996.
G. Baume † G. Carraro ‡ Y. Momany § 《Monthly notices of the Royal Astronomical Society》2009,398(1):221-232
We present optical ( UBVI C ) observations of a rich and complex field in the Galactic plane towards l ∼ 305° and b ∼ 0° . Our analysis reveals a significantly high interstellar absorption ( A V ∼ 10) and an abnormal extinction law in this line of sight. Availing a considerable number of colour combinations, the photometric diagrams allow us to derive new estimates of the fundamental parameters of the two open clusters Danks 1 and Danks 2. Due to the derived abnormal reddening law in this line of sight, both clusters appear much closer (to the Sun) than previously thought. Additionally, we present the optical colours and magnitudes of the WR 48a star, and its main parameters were estimated. The properties of the two embedded clusters, DBS2003 130 and 131, are also addressed. We identify a number of young stellar objects which are probable members of these clusters. This new material is then used to revisit the spiral structure in this sector of the Galaxy showing evidence of populations associated with the inner Galaxy Scutum-Crux arm. 相似文献
997.
B.B. Singh V.R. Chitnis D. Bose M.A. Rahman S.S. Upadhya K.S. Gothe B.K. Nagesh P.N. Purohit Shobha K. Rao Kamesh K. Rao S.K. Sharma P.V. Sudersan B.L. Venkateshmurthy P.R. Vishwanath B.S. Acharya 《Astroparticle Physics》2009,32(2):120-128
We present the results of observation of the Geminga pulsar carried out in the TeV energy band during the 6 year period spanning 2000–2006 using the Pachmarhi Array of Cherenkov Telescopes (PACT). A long stretch of data, new computer codes and the “Tempo” package have been used in the present analysis. We have searched for evidence of pulsed emission of γ-rays from the Geminga pulsar using the post-glitch pulsar elements obtained by Jackson and Halpern from X-ray/γ-ray satellite data. We do not see any significant evidence for pulsed emission from the Geminga pulsar at a threshold energy of 825 GeV. In this paper we present our results on the light curve in the TeV energy band, set an upper limit on the time averaged flux of γ-rays, and compare our results with other ground based observations. 相似文献
998.
M.J. Hwang Y.J. Kwon H.J. Kim J.W. Kwak S.C. Kim S.K. Kim T.Y. Kim S.Y. Kim H.S. Lee M.J. Lee S.S. Myung Y.D. Kim J.I. Lee W.G. Kang I.S. Hahn M.H. Lee KIMS Collaboration 《Astroparticle Physics》2009,31(6):412-416
A search for the neutrinoless double-beta decay of 124Sn was carried out using the tin-loaded liquid scintillator for an active source-detector technique. Tin (32.6%) in weight was successfully loaded into the liquid scintillator, and light output was as high as 57% of the unloaded liquid scintillator. A tin-loaded liquid scintillator with 1.1 ℓ volume was installed at the 700 m underground laboratory in YangYang, and data were taken for 5285 h. No evidence for the 0νββ decay was found and a lower limit on the 124Sn half-life was obtained to be 2.0×1019 year with 90% C.L. The new limit represents a significant improvement with respect to those previously available for 124Sn. 相似文献
999.
This article applies nonstandard analysis to derive jump conditions for one-dimensional, diverging, magnetogasdynamic shock
waves emerging on the surface of a star. It is assumed that the shock thickness occurs on an infinitesimal interval and the
jump functions for the flow parameters occur smoothly across this interval. Predistributions of the Heaviside function and
the Dirac delta measure are used to model the flow variables across a shock wave. The equations of motion expressed in nonconservative
form are then applied to derive unambiguous relationships between the jump functions for the flow parameters. It is shown
here that the equations modeling a family of magnetogasdynamic shock waves yield products of generalized functions that may
be analyzed consistently using nonstandard predistributions. 相似文献
1000.
论以科学发展观统引小康社会与现代化建设--浙江地区率先实现小康社会与现代化的理论与实践 总被引:1,自引:1,他引:0
冯拾松 《地球信息科学学报》2005,7(1):9-15
十六大确定了全面建设小康社会的目标,并提出有条件的地方可以发展得更快一些,在全面建设小康社会的基础上,率先基本实现现代化。作为沿海发达省市的浙江地区,以科学发展观为指导,根据浙江的实际,提出了到2020年全省基本实现现代化的奋斗目标,并为此制定了"八八战略",在全面建设小康社会和率先实现现代化的过程中进行了有益的实践。 相似文献