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1.
Kunde Yang Yuanliang Ma Chao Sun Miller J.H. Potty G.R. 《Oceanic Engineering, IEEE Journal of》2004,29(4):964-972
This paper discusses the results of geoacoustic inversion carried out using explosive charge data from the Asian Seas International Acoustic Experiment (ASIAEX) East China Sea (ECS) Experiment. A multifrequency incoherent matched-field inversion processor and a genetic algorithm (GA) are used for the inversion. A multistep matched field inversion approach is presented, which makes use of the varying sensitivities of wave fields at various frequencies to reduce the inversion problem into a sequence of smaller inversions with fewer unknowns to estimate at each stage. Different parameters are estimated using data at different frequencies according to their sensitivities. Inversion results for different areas in the ECS region are summarized and compared with core data. 相似文献
2.
3.
On September 14–18, 2000, a medium-small solar active region was observed at Ganyu Station of Purple Mountain Observatory. Its spots were not large, but it had a peculiar active filament. On Sep.16, a flare of importance IIIb with rather intense geophysical effects was produced. Our computation of the magnetic structure of the active region reveals that the rope-shaped filament was concerned with a low magnetic arc close to magnetic neutral line. An intense shear of magnetic field occurred near magnetic rope. The QSL analysis shows that a 3-D magnetic reconnection might appear in the vicinity of filament, and this can be used to interpret the formation of a large flare. 相似文献
4.
5.
L. Moreno J. J. Durán M. A. Casermeiro J. R. Quintana Ma A. Fernández 《Environmental Geology》2008,54(3):465-477
Over a period of 4 years and 4 months, the geopurification installations at Dehesas de Guadix (Granada, Spain) were monitored
to determine the impact on soil and groundwater of the controlled discharge of urban wastewater, and also to identify the
best indicators of the entry of the recharged water into the aquifer. The installations are located in an area where the climate
is Mediterranean sub-arid, with an average precipitation of less than 287 mm/year, and a rate of evapotranspiration that is
almost three times greater. The system was controlled by determining the balance of majority nutrients and boron in the soil
and in the groundwater, both at the points affected directly by the wastewater discharge and at others. The quantity of mass
discharged was relatively large (COD 14,656 g/m2, NO3 85 g/m2, NO2 4 g/m2, NH4 2,425 g/m2, PO4 1,143 g/m2, K 1,531 g/m2, B 63 g/m2). It was observed that the elimination of nutrients within the soil (COD 97.5%, PO4 94.4%, K 59.17%, N
total 18.8%, B 12.69%) was very efficient except for the nitrogen, which nevertheless did not reach the groundwater, as it was
eliminated at deep levels of the unsaturated zone. Only 12.69% of the boron was removed, and appreciable, increasing amounts
of this element did reach the groundwater. Unexpectedly, none of the majority nutrients behaved as a reliable indicator of
the impact on groundwater; despite this, the boron and the bicarbonate did clearly reflect the arrival of the recharged water,
and are proposed as the best indicators. 相似文献
6.
Qisheng Ma 《Geochimica et cosmochimica acta》2008,72(22):5446-5456
Formation of the Carbon-13 (13C) and deuterium (D) doubly-substituted methane isotopologues (13CH3D) in natural gases is studied utilizing both first-principle quantum mechanism molecular calculation and direct FTIR laboratorial measurements of specifically synthesized high isotope concentration methane gas. For 13CH3D, the symmetrically breathing mode A0 emerges as IR-detectable attributed to the molecular symmetry lowering to C3v from Td of the non-isotopic methane (CH4), along with a large vibrational frequency shift from ∼3000 to ∼2250 cm−1. Our studies also indicate that the concentration of 13CH3D is dependent on the environmental temperature through isotope exchanges among methane isotopologues; and the Gibbs’ Free Energy difference due to Quantum Mechanics Zero-Point vibrational motions has the major contribution to this temperature dependency. Potential geologic applications of the 13CH3D measurement to natural gas exploration and assessments are also discussed. In order to detect the 13CH3D concentration change of each 50 °C in the natural gas system, a 10−9 resolution is desirable. Such a measurement could provide important add-on information to distinguish natural gas origin and distribution. 相似文献
7.
Identifying China’s leading world city: a network approach 总被引:3,自引:0,他引:3
This paper reports our research on China’s world cities. Formal network analysis of air passenger linkages for recent years
among China’s most populous cities and among many of the world’s largest cities allows us to identify the country’s leading
world city from among the leading Mainland candidates, Beijing, Shanghai and Guangzhou. We theorize our findings about China’s
world cities in relation to both global forces (and China’s increasing entanglement with them) and the policies and actions
of the national state. We examine the national and global urban network through a longitudinal, two-level analysis of airline
passenger travel for four time points between about 1990 and 2005. We show that Beijing was China’s leading world city at
the beginning of the time period, a status it lost nationally in as early as 1995, and then globally 10 years later. On the
other hand Shanghai became China’s leading world city, and it acquired this status first nationally in 2000, and then globally
in 2005. The changing status of the Chinese capital corresponds to the country’s increasing involvement with the capitalist
world economy. Shanghai’s ascendance as the leading world city in China may indicate that global forces have come to play
an increasingly important role relative to that of the developmental state.
相似文献
Michael F. TimberlakeEmail: |
8.
固定式海洋平台利用TLD的减震研究 总被引:7,自引:0,他引:7
本文研究固定式海洋平台利用调谐液体阻尼器(TunedLiquidDamper,简称TLD)减小地震反应的方法。首先探讨了调谐频率比、激磁频率比对减震效果的影响,在此基础上建立了TLD——平台系统的力学模型和运动方程,通过数值计算验证了该方法的有效性 相似文献
9.
10.
SubunitcompositionandchromophorecontentofR-phycocyaninandallophycocyaninfromPorphyrahaitanensis¥GaoHongfeng;CaoWendaandJiMing... 相似文献