中国钢铁工业空间格局的演化及影响机制

钢铁工业作为基础性原材料工业,对国家或地区的经济社会发展有巨大的支撑作用。工业化和城市化进程会反作用于钢铁工业,促进其持续发展。由于中国不同地区的经济社会发展阶段不同,钢铁工业的空间格局因而呈现出分异。通过计算1985-2006年的钢产量的变异系数,探讨中国钢铁工业空间格局由集中转向扩散然后再次集聚的演化特征。20世纪70年代-80年代早期,中国钢铁工业主要集聚于辽宁、上海和湖北等少数省市;1985-2002年间,中国钢铁工业的空间分布逐渐向华北和华东地区扩散,钢铁工业的非均衡化发展态势有所缓和;2002年以后,这一空间格局逆转为向沿海地区特别是长三角和环渤海两大经济区集聚,中国钢铁工业的非均衡化发展态势再次加剧。其次,通过考察钢铁工业的产业集中度,在企业视角下考察中国钢铁工业空间格局的演化。最后,探讨了引导中国钢铁工业空间格局演化的影响机制,分析了市场需求、投资、原材料以及企业发展战略等因素在这一演化过程中的作用。     

对数比变换在因子分析法提取东亚冬季风敏感粒级中的应用——以南黄海中部泥质区H07孔为例

利用经典统计学分析等传统方法提取东亚季风敏感粒级时,往往因忽视了成分数据的闭合效应而造成对分析结果的误读,所确定的季风替代指标与已有指标的对应效果也不甚理想。以南黄海中部泥质区H07岩心为例,尝试对原始粒度数据做中心化对数比变换以消除闭合效应,再通过因子分析法从中提取出东亚冬季风敏感粒级,进而提出将F2因子得分值作为东亚冬季风强度的替代指标。结合AMS14C年代数据,重建了近6 200 aBP来的东亚冬季风演化历史,并将其划分为5个阶段：(1)6.2~4.99 kaBP,高水平强烈波动期;(2)4.99~3.66 kaBP,高水平小幅波动期;(3)3.66~0.87 kaBP,低水平亚稳定期;(4)0.87~0.14 kaBP,持续增强期;(5)0.14 kaBP至今,大幅减弱期。所提取的替代指标与其他气候指标有很好的对应,证明将中心化对数比变换引入到季风敏感粒级的提取过程中是可行的,能有效地揭示出更接近于真实的中国东部地区东亚冬季风演化历史。     

Resolution of Seamount Geoid Anomalies Achieved by the SARAL/AltiKa and Envisat RA2 Satellite Radar Altimeters

The resolution of seamount geoid anomalies by the SARAL/AltiKa Ka-band radar altimeter is compared with the Envisat RA2 Ku-band altimeter using cross-spectral analysis of exact-repeat profiles. Noise spectra show white noise floors at root-mean-square levels around 8 mm per root-Hz for AltiKa and 19 mm per root-Hz for RA2, and are colored at wavelengths longer than a few km, with a spectral hump similar to that seen in Jason-2 data. The AltiKa noise level is lower than the RA2 noise level by more than one would expect from the ratio of their pulse repetition frequencies. Large outliers are present in data from both altimeters, always of one sign (range too long), and show little correlation with rain or other error flags. Seamount anomaly signal to noise ratios are 30 to 10 dB for AltiKa and 3 to 8 dB less for RA2, decreasing as seamount size decreases. Seamounts as small as 1.35 km tall are resolved by both instruments, with significantly better performance by AltiKa due to its lower noise level. If AltiKa can fly a geodetic mission, it will find many presently unknown seamounts.     

一定厚度的油膜对海浪的抑制模型研究

本文结合海浪谱的作用量平衡方程,给出了一定厚度油膜对海浪的抑制模型,该模型不仅与油膜的物理参数有关,而且与环境参数有关。文中开展了抑制比对这些参数的敏感性分析,数值模拟结果表明:动力学粘性,表面/界面弹性、油膜厚度、油膜覆盖率等参数对抑制比的影响较大,但油膜的其他物理学参数如:密度、表面/界面张力,表面/界面粘度几乎对抑制比不产生影响;而且,文中还发现风速和风向对抑制比的影响较大。一般情况下,油膜对雷达回波信号的抑制,只需考虑油膜对海浪的抑制作用;但对厚乳化溢油而言,还应考虑到介电常数的减小对雷达回波信号的抑制。将本文建立的抑制比模型所得结果与墨西哥湾溢油事故期间的15景ENVISAR ASAR影像所得抑制比结果进行了比较。     

Geotechnical Investigations at the Dalian Offshore Airport,China

Based on the geotechnical investigation data of artificial island at Dalian Offshore Airport, the spatial distribution of the physical and mechanical properties of deposit soils was statistically analyzed. The field investigation revealed that the deposit soils could be subdivided into three strata, i.e., the top marine deposit stratum, middle marine-continental deposit stratum, and deep continental deposit stratum. Field and laboratory test results demonstrated that the marine deposit soils had high water content (31.2% < w_n < 63.10%), large void ratio (0.88 < e₀ < 1.75), low permeability (k_v < 10^?6 cm/s), flow-plastic state (I_L > 1), under consolidated (OCR < 1), high compressibility (E_s < 4 MPa), low shear strength (11.7 kPa < c_u < 43.7 kPa), and low bearing capacity (0 < f_ak < 120 kPa), they could not be used as natural foundation. The marine-continental and continental deposits were normally consolidated to over-consolidated (OCR ≥ 1), medium compressibility (4 MPa < E_s < 20 MPa), high shear strength (29.7 kPa < c_u < 73.7 kPa), and high bearing capacity (f_ak > 120 kPa). In addition, regression analysis results showed that the compression ratio was positively correlated with the natural water content, the coefficient of vertical consolidation was negatively correlated with the plasticity index, and the coefficient of vertical permeability was positively correlated with the initial void ratio. The results of the field and laboratory tests were synthesized to provide a basis for reclamation design.     

Distinctive stable isotope ratios in important zooplankton species in relation to estuarine salinity gradients: Potential tracer of fish migration

To assess the potential of stable isotope ratios as an indicator of fish migration within estuaries, stable isotope ratios in important zooplankton species were analyzed in relation to estuarine salinity gradients. Gut contents from migratory juveniles of the euryhaline marine fish Lateolabrax japonicus were examined along the Chikugo River estuary of the Ariake Sea, which has the most developed estuarine turbidity maximum (ETM) in Japan. Early juveniles in March and April preyed primarily on two copepod species; Sinocalanus sinensis at lower salinities and Acartia omorii at higher salinities. Late juveniles (standard length > 40 mm) at lower salinities preyed exclusively on the mysid Acanthomysis longirostris until July and complementarily on the decapod Acetes japonicus in August. These prey species were collected along the estuary during the spring–summer seasons of 2003 and 2004, and their carbon and nitrogen stable isotope ratios (δ¹³C and δ¹⁵N) were evaluated. The δ¹³C values of prey species were distinct from each other and were primarily depleted within and in close proximity to the ETM (salinity < 10); S. sinensis (−26.6‰) < Acanthomysis longirostris (−23.3‰) < Acartia omorii (−21.1‰) < Acetes japonicus (−18.5‰). The overall gradient of δ¹³C with salinity occurred for all prey species and showed minor temporal fluctuations, while it was not directly influenced by the δ¹³C values in particulate organic matter along the estuary. In contrast to δ¹³C, the δ¹⁵N values of prey species did not exhibit any clear relationship with salinity. The present study demonstrated that δ¹³C has the potential for application as a tracer of fish migration into lower salinity areas including the ETM.     

Generation characteristics of Mesozoic syn- and post-rift source rocks,Bonaparte Basin,Australia: New insights from compositional kinetic modelling

Potential source rocks on the Laminaria High, a region of the northern Bonaparte Basin on the North West Shelf of Australia, occur within the Middle Jurassic to Lower Cretaceous early to post-rift sequences. Twenty-two representative immature source rock samples from the Jurassic to Lower Cretaceous (Plover, Laminaria, Frigate, Flamingo and Echuca Shoals) sequences were analysed to define the hydrocarbon products that analogous mature source rocks could have generated during thermal maturation and filled the petroleum reservoirs in the Laminaria High region. Rock-Eval pyrolysis data indicate that all the source rocks contain type II–III organic matter and vary in organic richness and quality. Open system pyrolysis-gas chromatography on extracted rock samples show a dominance of aliphatic components in the pyrolysates. The Plover source rocks are the exception which exhibit high phenolic contents due to their predominant land-plant contribution. Most of the kerogens have the potential to generate Paraffinic–Naphthenic–Aromatic oils with low wax contents. Bulk kinetic analyses reveal a relatively broad distribution of activation energies that are directly related to the heterogeneity in the kerogens. These kinetic parameters suggest different degrees of thermal stability, with the predicted commencement of petroleum generation under geological heating conditions covering a relatively broad temperature range from 95 to 135 °C for the Upper Jurassic−Lower Cretaceous source rocks. Both shales and coals of the Middle Jurassic Plover Formation have the potential to generate oil at relatively higher temperatures (140–145 °C) than those measured for crude oils in previous studies. Hence, the Frigate and the Flamingo formations are the main potential sources of oils reservoired in the Laminaria and Corallina fields. Apart from being a reservoir, the Laminaria Formation also contains organic-rich layers, with the potential to generate oil. For the majority of samples analysed, the compositional kinetic model predictions indicate that 80% of the hydrocarbons were generated as oil and 20% as gas. The exception is the Lower Cretaceous Echuca Shoals Formation which shows the potential to generate a greater proportion (40%) of gas despite its marine source affinity, due to inertinite dominating the maceral assemblage.     

Thermal constraints on the respiration and excretion rates of krill,Euphausia hanseni and Nematoscelis megalops,in the northern Benguela upwelling system off Namibia

Rates of respiration and ammonia excretion of Euphausia hanseni and Nematoscelis megalops were determined experimentally at four temperatures representative of conditions encountered by these euphausiid species in the northern Benguela upwelling environment. The respiration rate increased from 7.7 µmol O₂ h^?1 g_ww ^?1 at 5 °C to 18.1 µmol O₂ h^?1 g_ww ^?1 at 20 °C in E. hanseni and from 7.0 µmol O₂ h^?1 g_ww ^?1 (5 °C) to 23.4 µmol O₂ h^?1 g_ww ^?1 (20 °C) in N. megalops. The impact of temperature on oxygen uptake of the two species differed significantly. Nematoscelis megalops showed thermal adaptations to temperatures between 5 °C and 10 °C (Q₁₀ = 1.9) and metabolic constraint was evident at higher temperatures (Q₁₀ = 2.6). In contrast, E. hanseni showed adaptations to temperatures of 10–20 °C (Q₁₀ = 1.5) and experienced metabolic depression below 10 °C (Q₁₀ = 2.6). Proteins were predominantly metabolised by E. hanseni in contrast to lipids by N. megalops. Carbon demand of N. megalops between 5 and 15 °C was lower than in E. hanseni versus equal food requirements at 20 °C. It is concluded that the two species display different physiological adaptations, based on their respective temperature adaptations, which are mirrored in their differential vertical positioning in the water column.     

Predictions of the OCR from Piezocone Tests in Quaternary Clays

As indicated by the profile of overconsolidation ratio (OCR), the stress history of a soil deposit is one of the dominant factors that influence the engineering behavior of soils. A commonly used method to obtain the parameter is the laboratory oedometer test, which is of low accuracy and time consuming because of inevitable sample disturbance. These difficulties can be overcome by in situ pizeocone penetration test, which provides continuous measurement of cone resistance, sleeve friction, and pore water pressure induced during the penetration. Though many methods have been proposed to estimate the preconsolidation pressure and overconsolidation ratio of clay deposits, their validity still needs to be proved. In this study, existing empirical methods for interpreting stress history of clays through piezocone tests are briefly reviewed. It is shown that regional correlations are valid. Piezocone tests utilizing a Vertek-Hogentogler CPTU truck that have been completed at different sites in the Jiangsu province of China. Existing correlations are compared with these field test data. It is shown that the correlation based on normalized net tip resistance is pretty accurate for determining the overconsolidation ratio of Quaternary clay deposits.     

Active diapirism and slope steepening,northern gulf of Mexico continental slope

Abstract

Large diapiric and nondiapiric masses of Jurassic salt and Tertiary shale underlie the northern Gulf of Mexico continental slope and adjacent outer continental shelf. These masses show evidence of being structurally active at present and in the very recent geologic past. Local steepening of the sea floor in response to the vertical growth of these structures is a serious concern to those involved in the site selection and the construction of future oil and gas production and transportation facilities in this frontier petroleum province.

The seabed of the northern Gulf slope is hummocky and consists of many hillocks, knolls, and ridges interspersed by topographic depressions and canyon systems. Topographic highs and lows relate respectively to vertical diapiric growth and to withdrawal of large volumes of salt and shale. Topographic highs vary considerably in shape and size, but all have very limited areas of nearly flat sea floor. Intraslope topographic lows consist of three principal types: (1) remnants of submarine canyons blocked by diapiric uplift that terminated active downslope sediment transport common during stages of low sea level; (2) closed depressions formed by subsidence in response to salt and shale withdrawal and flow into surrounding diapiric uplifts; and (3) small collapse basins formed by faulting in strata arched over structural crests of diapirs.

Distribution patterns of both diapiric features and sediment accumulations on the slope are the result of the complex relationship that exists between sediment loading and diapirism. Diapiric activity is proportional to the thickness of salt or underconsolidated shale available for mobilization, and to the sedimentary load distribution on these highly plastic deposits. Variations in overburden load, in turn, are dependent on rates, volumes, and bulk densities of depo‐sitional influx; proximity to sources of supply, erosion, and distribution of sediments; and topographic control of sediment accumulation. Sediment capture in diapirically controlled interdomal basins and canyon systems localizes overburden load, thus inducing further diapiric growth, and complex structural and stratigraphic patterns are induced throughout the continental slope region.

Drill cores in the slope province indicate that most of the slope sediments are fine‐grained muds; appreciable quantities of sand‐size sediment are present principally in canyon axes. Turbidite sand layers drilled on a topographic high adjacent to the Gyre Basin reflect uplift far above their original deposition level, and calculations yield rates of uplift that average 2 to 4 m per 100 years. Seismic reflection profiles provide considerable evidence of “fresh”; slumps and ero‐sional surfaces on the flanks of many topographic highs not yet blanketed by a veneer of young sediments. This evidence thus supports our conclusion that the present continental slope region of the northern Gulf of Mexico is undergoing active diapirism and consequent slope steepening. Because most of the sediment on the flanks of diapiric structures consists of underconsolidated muds, slumping will take place regularly in response to further diapiric movement.