全球化下地方综合服务型物流企业的空间网络组织——以腾邦物流为案例

全球化与地方发展理论是当前经济地理学研究的热点领域。地方综合服务型物流企业作为现代物流业的主体,参与到全球生产网络中,但学术界对基于企业层面的空间网络组织研究较薄弱。采用案例分析研究方法,通过实地调研获取数据资料,对综合服务型物流企业的空间网络组织进行深入分析。研究发现:地方综合服务型物流企业空间网络一般由总部—分公司—办事处(或营业部)三级构成,各级机构设置影响因素存在差异;企业空间网络呈"核心—边缘"模式;空间网络扩张呈现"先地方,后国际"的时间特征和"接触式扩散+跳跃式扩散"的空间特征;地方部分物流企业空间网络受到国际化和全球化的影响。     

浅层折射波数据处理软件的开发

在简要阐述浅层折射波法的原理和t0法基础上,通过折射波数据处理软件的开发,提高了浅层地震勘探的工作效率,并运用t0折射波法的原理,实现计算机的自动成图,联合剖面有助于更好的观察地下构造。同时也提出一些更好的计算机实现方法和算法,通过它在丹东艾河水利枢纽工程勘察中的应用,证明了该软件解释精度高,操作简便。     

Prediction of the tunnel displacement induced by laterally adjacent excavations using multivariate adaptive regression splines

Excavations may cause excessive ground movements, resulting in potential damage to laterally adjacent tunnels. The aim of this investigation is to present a simple assessment technique using a multivariate adaptive regression splines (MARS) model, which can map the nonlinear interactions between the influencing factors and the maximum horizontal deformation of tunnels. A high-quality case history in Tianjin, China, is presented to illustrate the effect of excavation on the tunnel deformation and to validate the FEM. The hypothetical data produced by the FEM provide a basis for developing the proposed MARS model. Based on the proposed model, the independent and coupled effects of the input variables (i.e. the normalized buried depth of tunnels H_t/H_e, the normalized horizontal distance between tunnels and retaining structures L_t/H_e, and the maximum horizontal displacement of retaining structures, δ_Rmax) on the tunnel response are analysed. The prediction precision and accuracy of the MARS model are validated via the artificial data and the collected case histories.

     

转型期广州市居住迁移的分阶段比较

将住房制度改革划分为起步、房改售房和住房市场化3个阶段,利用大规模的入户调查资料,分析不同阶段城市居民的居住迁移影响因素差异.研究发现,住房制度改革以来广州市年均居住迁移率呈波动上升趋势,1998年货币分房政策的实施引发大规模的居住迁移,导致城市空间大规模重构;利用事件史分析方法分析发现家庭生命周期、工作单位变动、住房产权和住房性质选择等都显著影响居住迁移,但不同阶段其作用机制和影响程度存在明显差异.起步阶段的居住迁移仍是制度安排下的被动迁移;市场化阶段的居住迁移自发性增强;房改售房阶段两种体制并存,居住迁移行为相对更复杂.随着住房市场化程度的进一步增强,家庭生命周期因素和社会经济地位的变化对居住迁移的影响将会增强.     

Contributions of the Bering Strait throughflow to oceanic meridional heat transport under modern and Last Glacial Maximum climate conditions

Paleo reconstructions and model simulations have suggested the Bering Strait plays a pivotal role in climate change. However, the contribution of the Bering Strait throughflow to oceanic meridional heat transport(OMHT) is about 100 times smaller than the OMHT at low latitudes in the modern climate and it is generally ignored. Based on model simulations under modern and Last Glacial Maximum(LGM,～21 ka; ka=thousand years ago) climate conditions, this study highlights the importance of the Bering Strait throughflow to OMHT. The interbasin OMHT induced by the Bering Strait throughflow is estimated by interbasin-intrabasin decomposition. Similar to barotropic-baroclinic-horizontal decomposition, we assume the nonzero net mass transport induced by interbasin throughflows is uniform across the entire section, and the interbasin term is separated to force zero net mass transport for the intrabasin term. Based on interbasinintrabasin decomposition, the contribution of the Bering Strait throughflow is determined as ～0.02 PW(1 PW=10 15 W) under the modern climate, and zero under the LGM climate because the closed Bering Strait blocked interbasin throughflows. The contribution of the Bering Strait throughflow to OMHT is rather small, consistent with previous studies. However, comparisons of OMHT under modern and LGM climate conditions indicate the mean absolute changes are typically 0.05 and 0.20 PW in the North Atlantic and North Pacific, respectively. Thus, the contribution of the Bering Strait throughflow should not be ignored when comparing OMHT under dif ferent climate conditions.     

Co-variation of the surface wind speed and the sea surface temperature over mesoscale eddies in the Gulf Stream region:momentum vertical mixing aspect

The co-variation of surface wind speed and sea surface temperature(SST)over the Gulf Stream frontal region is investigated using high-resolution satellite measurements and atmospheric reanalysis data.Results show that the pattern of positive SST-surface wind speed correlations is anchored by strong SST gradient and marine atmospheric boundary layer(MABL)height front,with active warm and cold-ocean eddies around.The MABL has an obvious transitional structure along the strong SST front,with greater(lesser)heights over the north(south)side.The significant positive SST-surface wind-speed perturbation correlations are mostly found over both strong warm and cold eddies.The surface wind speed increases(decreases)about 0.32(0.41)m/s and the MABL elevates(drops)approximate 55(54)m per 1℃ of SST perturbation induced by warm(cold)eddies.The response of the surface wind speed to SST perturbations over the mesoscale eddies is mainly attributed to the momentum vertical mixing in the MABL,which is confirmed by the linear relationships between the downwind(cro sswind)SST gradient and wind divergence(curl).     

Seasonal response of surface wind to SST perturbation in the Northern Hemisphere

The seasonal response of surface wind speed to sea surface temperature (SST) change in the Northern Hemisphere was investigated using 10 years (2002-2011) high-resolution satellite observations and reanalysis data. The results showed that correlation between surface wind speed perturbations and SST perturbations exhibits remarkable seasonal variation, with more positive correlation is stronger in the cold seasons than in the warm seasons. This seasonality in a positive correlation between SST and surface wind speed is attributable primarily to seasonal changes of oceanic and atmospheric background conditions in frontal regions. The mean SST gradient and the prevailing surface winds are strong in winter and weak in summer. Additionally, the eddy-induced response of surface wind speed is stronger in winter than in summer, although the locations and numbers of mesoscale eddies do not show obvious seasonal features. The response of surface wind speed is apparently due to stability and mixing within the marine atmospheric boundary layer (MABL), modulated by SST perturbations. In the cold seasons, the stronger positive (negative) SST perturbations are easier to increase (decrease) the MABL height and trigger (suppress) momentum vertical mixing, contributing to the positive correlation between SST and surface wind speed. In comparison, SST perturbations are relatively weak in the warm seasons, resulting in a weak response of surface wind speed to SST changes. This result holds for each individual region with energetic eddy activity in the Northern Hemisphere.     

上海地下工程的技术问题

进入９０年代以来,上海的建（构）筑物迅速向高、大、深、重的方向发展,从而使地下工程的试验、研究、设计、施工和监测,成为上海岩土工程界的主攻方向。在软土地基上进行桩基旋工、开挖深基坑和沉井工程,都会对软弱土体产生扰动和破坏,推动稳定性的土体所表现的应用应变复杂过程,随时都会给工程带来危害。上海岩土工程界从众多工程事故实例中取得经验教训,摸索到一套行之有效的办法,对于常见的上海地下工程技术问题,从原理     

The inter-annual variability of the Yellow Sea Warm Current surface axis and its influencing factors

Based on the Pathfinder sea surface temperature(PFSST),the surface axis and its pattern of the Yellow Sea Warm Current(YSWC) are discussed.A structure of double-warm-tongue is found in February and it varies in different years.Two indexes are calculated to represent the westward shift(WSI) and northward extension(NEI) of the warm water in the Yellow Sea(YS).Wavelet analysis illustrates that the WSI and NEI have prominent periods of 3-6 years and 3-4 years,respectively.The Empirical Orthogonal Function(EOF) ...