异质性“通道”与跨国公司地方化结网——以苏州工业园为例     

艾少伟  苗长虹 《地理研究》2011,30(8):1483-1498

在经济全球化时代,跨国公司是开发区形成、发展和演进的关键驱动力量。在多种异质性行为主体交互作用所形成的＂学习场＂中,跨国公司要实现其全球化和本土化战略,就必须与开发区政府和本土企业之间建立有效的地方化结网＂通道＂。其中,＂政策通道＂首先为其提供了最基本的＂通道＂保障,成为跨国公司进驻开发区的初始动因。通过技术、市场等各...  相似文献   

Fine‐grained bed sediment storage within the main channel systems of the Frome and Piddle catchments,Dorset, UK     

A. L. Collins  D. E. Walling 《水文研究》2007,21(11):1448-1459

Lowland permeable catchments in the UK are particularly prone to sedimentation problems, on account of the increased fine sediment loadings generated by recent land‐use change and their stable seasonal hydrological regimes, which are frequently depleted by groundwater abstraction. Fine‐grained sediment storage on the bed of the main channel systems of the Frome (437 km²) and Piddle (183 km²) catchments, Dorset, UK, has been examined at 29 sites using a sediment remobilization technique. Measurements encompassed the period February 2003–July 2004. At individual sites in the Frome, average values ranged between 410 and 2630 g m^?2, with an overall mean of 918 g m^?2. In the Piddle, the average values for individual sites varied between 260 and 4340 g m^?2, with an overall mean of 1580 g m^?2. Temporal variations in fine bed sediment storage at each site were appreciable, with the coefficients of variation ranging between 43 and 155% in the Frome and between 33 and 160% in the Piddle. Average reach‐scale specific bed sediment storage increased markedly downstream along each main stem from 2 to 29 t km^?1 (Frome) and from 4 to 19 t km^?1 (Piddle). Total fine sediment storage on the channel bed of the Frome varied between 479 t (5 t km^?1) and 1694 t (17 t km^?1), with a mean of 795 t (7 t km^?1), compared with between 371 t (5 t km^?1) and 1238 t (14 t km^?1) with a mean of 730 t (9 t km^?1) in the Piddle. During the study period, fine bed sediment storage was typically equivalent to 18% (Frome) and 57% (Piddle) of the mean annual suspended sediment flux at the study catchment outlets. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

STUDY ON ANTI-NOISE SCHEME FOR DETECTING PPM INFORMATION IN SHALLOW WATER CHANNELS     

粘宝卿  黄衍镇  蒋志迪 《中国海洋湖沼学报》1999,17(3):278-283

INTRODUCTIONThemultipatheffect,signalfluctuation (Huangetal.,1 998a,b) ,andnoiselevelinshallowwaterchannelshinderdetectionofpulsepositionmodulation (PPM)information .Thispaperdis cussesmarinenoisehindrancetoprecisedetectionofPPMinformation ,andpresentssomefeasiblecountermeasurestosuppressnoiseinterferenceeffectively .Itiswellknowneffectivedetectionofinformationbyareceivingsystemiscruciallydependentonthesignal to noiseratio(SNR) .Asrelativelyhighnoiselevelexistsinshallowwateracousticch…  相似文献   

Estimation of suspended sediment loads and delivery in an incised upland headwater catchment,south‐eastern Australia     

Hugh G. Smith 《水文研究》2008,22(16):3135-3148

Historically upland headwater catchments in south‐eastern Australia have undergone extensive gully erosion that has removed large amounts of sediment to lowlands. Recent research suggests these upland areas may continue to dominate fine sediment loads in lowland rivers. Improved understanding of sediment transfer through upland headwater catchments may have implications for interpreting downstream sediment supply. In this study a nested catchment design was utilized to examine suspended sediment yields and delivery from a small tributary sub‐catchment (1·64 km²) to the study catchment outlet (53·5 km²). Monitoring of suspended sediment concentration and discharge was undertaken for a period of nearly two years and used to estimate suspended sediment loads. Estimated total suspended sediment exports over the period of monitoring were 24·16 t from the sub‐catchment and 550·3 t from the catchment, which are generally less than previous reported small catchment yields in south‐eastern Australia. The extent of sediment delivery was examined using between‐site ratios of specific sediment yield per unit area and incised channel length. Sediment delivery was high under average rainfall conditions, but seasonally dependent. Both suspended sediment yields and the extent of delivery peaked over spring months, supplemented by remobilization of sediment stored during summer months in the main catchment channel. The findings of this study suggest much of the suspended sediment exported from small incised upland sub‐catchments (1–2 km²) may be delivered to downstream reaches under average rainfall conditions, which, in conjunction with the findings of previous research supports the potential importance of contributions from these areas to suspended sediment loads in lowland rivers during high flow periods. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

水流流量计的设计与开发     

王杰  文斌  高瑜翔 《成都信息工程学院学报》2006,21(Z1):26-29

采用水压传感器、流速传感器、 STC89C58RD MCU等器件的明渠流量测量仪表能自动完成流态判别、流量公式和流量参数选择,实时获得明渠流量.具有成本低、精度高、安装使用简便、可广泛应用等优点.  相似文献   

试析制约港口航道测绘发展的若干因素     

偶卫军 《地理信息世界》2000,(4)

海事系统港口航道测绘在市场竞争中面临严峻的挑战，这就需要领导干部具有创新意识，职工具有竞争意识，依靠科技力量壮大队伍，同时加强内部管理，建立良好的海测服务机制，使港口航道测绘事业健康发展。从沿海港口航道测绘发展需求的角度探讨正在和可能制约海事系统港口航道测绘进一步发展的几大因素。  相似文献   

TTC模式下的集群系统在局域移动通信网中的应用     

王春圃 《成都信息工程学院学报》2000,15(3):255-260

介绍了一种成本低、见效快 ,适用于建立专用局域网的美国最新无线移动通信模式———TTC模式下的集群系统的结构、工作流程、特点及建网的几点建议。  相似文献   

Using a fluctuating tracer to estimate hyporheic exchange in restored and unrestored reaches of the Truckee River,Nevada, USA     

Andrew E. Knust  John J. Warwick 《水文研究》2009,23(8):1119-1130

The goal of this research was to compare hyporheic activity in recently restored and adjacent un‐restored reaches of the Truckee River downstream from the Reno/Sparks metropolitan area. The installation of rocky riffles and raised channel bed elevations in the restored reaches may have increased the degree of surface–subsurface interaction. A fluctuating chloride concentration signal served as the tracer, induced by the variable influx of higher salinity water several miles upstream from the study reach. The solute transport model, OTIS, was used in conjunction with the hydrodynamic model, DYNHYD5, to estimate transient storage parameters under unsteady flow conditions. The model was calibrated to chloride concentrations measured over a period of three days at six in‐stream locations representing restored and un‐restored reaches. An automated parameter estimation algorithm (SCE‐UA) was used to optimize parameters for multiple reaches simultaneously and generate a distribution of parameter estimates. Results suggest that the transient storage zone cross‐sectional area (A_s) is larger in the restored reaches than in the unrestored reaches, but the exchange coefficient (α) is smaller, leading to increased hyporheic residence time and hydrologic retention in the vicinity of channel reconstructions. Scenarios were used to simulate the potential effects of increased subsurface residence time on denitrification and in‐stream NO₃‐N concentrations. Monte Carlo analysis was performed to assess uncertainty in the simulation results and show the potential for greater nutrient retention in the lower Truckee River as a result of channel restoration. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

隔河岩遥测地震台网无线信道计算及测试     

倪焕明  宁积艮 《大地测量与地球动力学》1997,(4)

隔河岩遥测地震台网是由７个遥测地震台、２个中继站和１个接收记录中心组成的地方性遥测台网，其目的是监测隔河岩水库诱发地震活动。台网的合理布局保证了在台网检测范围内地震定位的精度优于Ⅰ类，重要地段的地震监测能力为ＭＬ≥０．５级。台网采用了２２３ＭＨｚ频段的无线传输地震遥测设备。测试结果表明，无线信道功率裕量均在３０ｄＢ以上，信道可靠性优于９９．９９％，各道信号实际连续率在９９．６７％以上，超过规范规定的要求。自１９９３年运行以来，获得了高质量的产出。  相似文献   

直流电源故障的微机检测     

韩玉英 《成都信息工程学院学报》2002,17(3):188-191

介绍了利用IMB－PC 8088CPU的单板机控制检测多路直流电源过压、欠压。在出现此类故障时能发出报警声，并在显示器上显示故障电源编号，同时切断故障电源，启动同类备用电源，以便维修。  相似文献