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21.
The present paper focuses for the first time on the trace fossils present in carbonate tests of the famous Egyptian middle Eocene larger foraminifer Nummulites gizehensis group. Bioerosion is represented by a unique diversified assemblage of seven ichnospecies belonging to four ichnogenera. Diagnostic drilling holes of the ichnogenus Oichnus are represented by the three ichnospecies O. simplex, O. paraboloides and O. asperus. Rare spiral galleries of Trypanites helicus and sinuous tunnels of Maeandropolydora sulcans were identified. Simple U-shaped borings of Caulostrepsis taeniola and Caulostrepsis isp. were also recognized within the studied nummulites. The reported drilling holes are attributed essentially to the predation of gastropods, whereas the other recognized galleries are assigned mainly to boring activities of the polychaete worms. Well-preserved tests with rare bioerosion and encrustation indicate deposition under a high rate of sedimentation and no prolonged transportation. Conversely, taphonomic characteristics of the bioeroded and encrusted nummulites can be used as good palaeoecological indictors of a deposition under low to fair rate of sedimentation. Coexistence of non-bioeroded and bioeroded/encrusted tests, common thick-bedded nummulite wackestone and packestone, predominated larger and flat Nummulites spp., and non-preferred imbrications are taken altogether with the reported ichnological assemblage to suggest that the nummulites were accumulated in situ and/or under weak influence of physical processes (storm and waves) in a shallow-marine environment, possibly middle to inner carbonate ramps.  相似文献   
22.
Forty-three samples of (1) Sirban Limestone of Riasi, Jammu and Kashmir State, India, based on six mineralogic and petrographic presence-absence variables, and (2) 36 samples of Bilaspur Limestone based on 11 presence-absence mineralogic and petrographic variables, were numerically classified by Q-mode cluster analysis using Sokal and Michner's Simple Matching Coefficient. Sirban Limestone of Riasi yielded 10 clusters or groups indicating four depositional environments: (1) intertidal, (2) intertidal to subtidal, (3) subtidal, and (4) deep-water basinal. Similarly, Bilaspur Limestone yielded nine clusters indicative of the same four environments. A Q-mode ordination of the Riasi samples and of Bilaspur Limestone shows a generalized shelf-to-basin carbonate deposition profile. Results of this study substantiate earlier conclusions of Rao (1979) based on field, mineralogic, and petrographic study of the above-mentioned carbonates.  相似文献   
23.
In the Abu Rusheid area, Southeastern Desert of Egypt, polymineralized (HREEs, U, Zn and Pb) lam-prophyre dykes are recently recorded. The lamprophyre dykes cut cataclastic rocks along share zones in NNW-SSE trends. The secondary U-minerals are essentially represented by uranophane, kasolite, torbernite and autunite. Ex-perimental work was carried out on the lamprophyre dykes for the recovery of uranium and other valuable elements (e.g. Zn, Pb and Al) from 50 kg of technological sample. The optimum conditions were: 100 g/L sulfuric acid con-centration, 1:5 S/L (solid/liquid) and soaking for 15 days at room temperature. The leaching efficiencies for the re-covery of uranium and other elements like Al, Zn and Pb were 40, 33.6, 98.8 and 78, respectively.  相似文献   
24.
Nowadays many continuously operating reference stations (CORS) network were established in Middle East to improve the surveying tasks. Establishing such geodetic control networks can be a costly business where multiple stations should be occupied simultaneously and post-processed with scientific software. Recently, precise point positioning (PPP) provides precise positioning values that may be an alternative to precise relative processing. The current research aims to investigate that PPP has a potential as a reliable absolute positioning technique operational simplicity as well as to investigate the capability of PPP approach to be a low cost alternative to the conventional positioning methods used in position determination of core networks stations. In comparison with common relative GPS techniques, the costs are reduced; because no base stations and no simultaneous observations are necessary, no need for control network maintenance which could be the most defective factors that Egypt HARN network suffered from. To see the feasibility study of using PPP for precise determination of the CORS, 14 days of GNSS data for the 14 Kuwait integrated with 27 IGS stations were processed by Bernese software to calculate the precise coordinates of Kuwaiti CORS network in the latest terrestrial geodetic frame. Three days of these data were processed by Trimble business center software and using PPP approach to calculate the precise coordinates of Kuwait network. In the current research, a comparable investigation was carried out between the coordinates obtained from Bernese software, Trimble business center, and PPP approach. The comparison proved high level of agreement between the coordinates which confirm that PPP approach can be applied for establishment of CORS network.  相似文献   
25.
The use of antifouling paints to the boats and ships is one among the threats facing coastal resources including coral reefs in recent decades. This study reports the current contamination status of diuron and its behaviour in the coastal waters of Malaysia. The maximum concentration of diuron was 285 ng/L detected at Johor port. All samples from Redang and Bidong coral reef islands were contaminated with diuron. Temporal variation showed relatively high concentrations but no significant difference (P > 0.05) during November and January (North-East monsoon) in Klang ports (North, South and West), while higher levels of diuron were detected during April, 2012 (Inter monsoon) in Kemaman, and Johor port. Although no site has shown concentration above maximum permissible concentration (430 ng/L) as restricted by the Dutch Authorities, however, long term exposure studies for environmental relevance levels of diuron around coastal areas should be given a priority in the future.  相似文献   
26.
The aim of this study was to look for high efficient bioflocculant-producing microorganisms. Among 36 bacterial colonies isolated from a crude petroleum oil sample, three of them as Bacillus subtilis and Pseudomonas spp. exhibited flocculation activity exceeding 90 % after 3 days of cultivation. They were identified by 16 S rDNA sequence analysis as Bacillus subtilis and Pseudomonas sp. Spectroscopic analysis of the polymers by nuclear magnetic resonance and fourier-transform infrared revealed that the polymers were glycoproteins. These polymers were soluble in water and insoluble in any organic solvents tested. The effects of bioflocculant dosage, temperature and pH on the flocculation activity were evaluated. The maximum bioflocculation activities were observed at an optimum bioflocculant dosage of 3.5 mg/L (strains Bacillus subtilis and Pseudomonas) and 5.0 mg/L (strain CPO14), respectively. In addition, these biopolymers were able to flocculate kaolin suspension (5 g/L) over a wide range of pH (pH 3–9) and temperature (5–50 °C) tested in the presence of CaCl2. The highest flocculation activities of strains CPO8, CPO13 and CPO14 were 96.03 %, 92.17 % and 97.59 %, respectively in the early stationary phase (at 24 h), while the cell production reached its maximum in the stationary phase (at 72 h). Their efficient flocculation capabilities suggest potential applications in industries.  相似文献   
27.
GPS Solutions - The surveillance function of air traffic management is critical to aviation safety. It determines the identity of an aircraft, its state and intent to support air traffic...  相似文献   
28.
The determination of high-resolution geoid for marine regions requires the integration of gravity data provided by different sources, e.g. global geopotential models, satellite altimetry, and shipborne gravimetric observations. Shipborne gravity data, acquired over a long time, comprises the short-wavelengths gravitation signal. This paper aims to produce a consistent gravity field over the Red Sea region to be used for geoid modelling. Both, the leave-one-out cross-validation and Kriging prediction techniques were chosen to ensure that the observed shipborne gravity data are consistent as well as free of gross-errors. A confidence level equivalent to 95.4% was decided to filter the observed shipborne data, while the cross-validation algorithm was repeatedly applied until the standard deviation of the residuals between the observed and estimated values are less than 1.5 mGal, which led to the elimination of about 17.7% of the shipborne gravity dataset. A comparison between the shipborne gravity data with DTU13 and SSv23.1 satellite altimetry-derived gravity models is done and reported. The corresponding results revealed that altimetry models almost have identical data content when compared one another, where the DTU13 gave better results with a mean and standard deviation of ?2.40 and 8.71 mGal, respectively. A statistical comparison has been made between different global geopotential models (GGMs) and shipborne gravity data. The Spectral Enhancement Method was applied to overcome the existing spectral gap between the GGMs and shipborne gravity data. EGM2008 manifested the best results with differences characterised with a mean of 1.35 mGal and a standard deviation of 11.11 mGal. Finally, the least-squares collocation (LSC) was implemented to combine the shipborne gravity data with DTU13 in order to create a unique and consistent gravity field over the Red Sea with no data voids. The combined data were independently tested using a total number of 95 randomly chosen shipborne gravity stations. The comparison between the extracted shipborne gravity data and DTU13 altimetry anomalies before and after applying the LSC revealed that a significant improvement is procurable from the combined dataset, in which the mean and standard deviation of the differences dropped from ?3.60 and 9.31 mGal to ?0.39 and 2.04 mGal, respectively.  相似文献   
29.
30.
In the recent decade, biosynthesis of the degradable biopolymers polyhydroxyalkanotes in transgenic yeasts became an important research task. Most research strategies depend on either metabolic engineering or molecular approaches. In the present work, research compared PHA biosynthesis in two types of yeasts; Saccharomyces cerevisiae and a non-convenient Kloeckera spp. Yeast strains were equipped in their cytoplasm with the phaABCRe operon containing genes phbA, phbB and phbC of the PHA biosynthetic pathway of Ralstonia eutropha, which encode β-ketothiolase, NADPH-linked acetoacetyl-CoA reductase and PHA synthase, respectively. The transgenic strains Saccharomyces cerevisiae and Kloeckera sp. were able to produce PHA. The maximum content of the polymer detected in the recombinant strain INVSc1/PHA1 was 2.68 % and only poly-3-hydroxybutyrate (PHB) accumulated. However, the non-conventional transgenic strain KY1/PHA was able to accumulate as maximum of 7.06 % of the copolymer poly-(3-hydroxybutyrate-co-poly-3-hydroxyvalerate) (PHV). Western blot analysis confirmed expression of the phaABCRe operon in the transgenic yeast strains. The nature of the PHA thus produced by all tested strains was analyzed by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy.  相似文献   
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