Experiment Study on the Influence of TGP Regulate Peak Flood to the Navigational Condition Between Two Dams

The experiment study on influence of TGP regulation the peak flood to the navigational condition between Two Dams shows: The regulation peak has the characteristic with large discharge,widely discharge variation and water level fluctuant and so on.During the adjust peak,the velocity and slope during two dams are higher than low water evidently,and the influence on navigation is obvious.When the released discharge diurnal average is between 10 000 and 15 000 m~(3)/s,the navigation condition can meet the requirement of 10 000 T ship team,but when the discharge exceed 20 000 m~(3)/s,the velocity and slope at important bar between two dams are near or over the allowable value,the upward ship team sail difficultly.     

Analysis on Effects of Constructions Building nearby the River Bank or across the River on Navigation Conditions

In this paper, the effects of construction nearby the river or across the river are analyzed on navigation conditions, such as navigation scales, navigation flow conditions, navigation way, navigation method and navigation aids. Some safety measures during its construction are presented.     

Sediment Aggregation and Regulation for Chongqing Reach of the Fluctuating Backwater District in Three Georges Reservoir

Chongqing downtown river reach lies in the fluctuating backwater district of Three Gorges Reservoir(TGR).After running on the 175M scheme of the TGR,it shows that the deposits increase accumulatively with the TGR running in the downtown reach,the bed sand will be finer,the river bar will be widen and higher,there will be bed evolution and the backwater area upwards.The sediment aggregation brings out important influence on harbor,navigation,the infrastructures and eco-environment along both banks of the reach.Combined with various respects of research achievements,the main engineering measurements are put forward in order to decrease the influence,such as soil conservation and building reservoirs upstream to prevent sand sedimentation,narrowing the flow to wash sand,bank regulation,harbor reconstruction and navigable channel treatment,etc.These measures have very good effect on decreasing deposition and eliminating the negative effects.     

Studies on the Type Selection of the Filling and Emptying System of Yingpan Lock on Wujiang River

Yingpan lock is the highest single level lock at present in China with a working head of 36.5m.This paper presents a regulation tank lock scheme and the water saving lock scheme to settle the valve hydraulics problem caused by high water head.By analyzing and comparing of the general single level lock,the regulation tank lock and the water saving lock,it is concluded that not only the recommended water saving lock can satisfy the design and the correlated operation requirements,reduce the valve work head by a half to simplify value hydraulics problem,but the water saving is possible at least by 48.6% in one ship passage through the lock.     

Influence of the Flood-Control-Projects on the Hydrodynamic State of the Rivers Confluence in Chongqing

Though the Flood-Control-Projects along Yantze River and Jialing River in Chongqing may well improve the urban traffic and construction,it may change the river hydrodynamic characters.There may be two consequences,one is to reduce the size of cross section and the other is to change the river shape,such as the curvature radius.The phenomena of the local backwater and velocity variety are obvious,which result in some problems for the navigation: sediment,transport and so on.In this paper, the study object is the Flood-Control-Projects and Yangtse River and Jialing River,and the aim is to study the influence of the Flood-Control-Projects on the hydrodynamic state of the two rivers.Using the numerical technique,with the two rivers hydrodynamic model the flow field's change of river after completion of Flood-Control-Projects is simulated and the reasons caused by the change are analyzed.     

Study on the Ship Navigation Process after Construction of the Yangtze River Bridge in Sutong City

In this paper, the equations of ship and current motion model are established. The calculation of the ship manipulative capability parameter is consistent with the measured in static stream. Through the ship motion model, the layout of the navigation route and the change of the ship manipulative capability parameter due to the Yangtze River Bridge in Sutong City are studied.     

Study on the Navigation Flow Condition at Entrance Area of the Ship Approach Channel for Jinghong Power Station on the Lancang River

Based on the model test of Jinghong power station on the Lancang river, the unfavorable navigation condition at entrance area of down approach channel of the ship lift is measured and analyzed for original design scheme of the project, and the open -type guide works is applied to greatly improve the bad flow condition, so as to make the navigation condition better at entrance area.     

Investigation on Direct Navigation across Fujian-Taiwan Strait and Ship Type Selection

Based on analysis of the natural conditions of Taiwan Strait and conditions for navigation of Fujian and Taiwan harbors, the direct navigation across Fujian-Taiwan Strait and selection of optimal ship type are investigated.     

Analytical and Experimental Study on Performances of MR Fluid Dampers Employing Plates Channel Model

The numerical model,which combines the two-dimensional river model and ship maneuvering mathematical model,is built.The influence of Nanjing Fourth Bridge to be built across the Changjiang River on river's condition is studied.The change of river conditions around the Bridge pier is analyzed and the tracks of ship transit along the reach of the Changjiang River are simulated for the cases of before and after building the Nanjing Fourth Bridge.The parameters of navigation in sail course have been obtained.The result shows that the influence on rivers condition of the Nanjing Fourth Bridge on Changjiang River is very small,and its influence on navigation is not significant.     

Soil erosion in catchments and experimental plots on Java (Indonesia) and Luzon (the Philippines)

Soil erosion was studied in the Serayu (Indonesia) and Bicol (The Philippines) catchment areas as there was a need to reduce sediment discharge. Water is diverted at Gambarsari (Indonesia) for rice irrigation; deposition in the feeder canal requires costly dredging maintenance. Erratic deposition in the Bicol plain impedes rice cultivation.Monitoring sediment discharge at gauging stations showed that in both cases a limited heavily eroded (450 t/ha/year) area supplied most of the material. Monitoring erosion rates on experimental plots showed that, as a general rule, soil loss was minimal (5–25 t t/ha/year) and of the same order of magnitude as pyroclastic deposition (5 t/ha/year).Soil conservation methods are ineffective when soil losses are either very high or very low. In both cases preliminary standard watershed management attempts failed as they were the result of technical inadequacy based on the incorrect assumption that there was generalized sheet and rill erosion.Sediment deposition at the Gambarsari intake would be strongly reduced by proper dam design and sediment flushing. Sediment deposition in the Bicol plain should be directed to warping enclosures.     

Discussion on 2-D Math Model of Sediment in Gravel Dominantly Riverbed

The present paper gives a discussion about transport coefficient of suspended sediment, coefficient of saturation recovery, riverbed sediment grading, deposition/scour thickness and normalization of the sediment composition in gravel dominantly riverbed. The math model above mentioned has been tested in two rivers with different riverbed sediment composition and a rather good agreement has been obtained.     

Suspended-sediment transport in the Dollard estuary

For an analysis of suspended-sediment transport in the Dollard estuary, water samples were taken and current velocities and directions measured on the tidal flats and in the channels. Measurements carried out during fair-weather conditions in summer were compared with measurements carried out during a heavy gale in winter. During the onset of the flood, high suspended-sediment concentrations occurred as a result of resuspension of the top layer of the bottom sediment. Measurements carried out in the channels pointed to sediment transport from the estuary seaward, but inward transport over the flats during fair weather apparently compensates for the outflow during ebb and storms: the result is a net deposition in the order of 1 to 2 mm (up to 8 mm) per year, as previously observed in this area.     

洪泽湖输沙淤积、底泥理化特性及重金属污染变化特征分析

基于洪泽湖近20年来的相关研究,对洪泽湖输沙量和底泥的分布特征及理化性质各指标的含量等数据进行了搜集处理和分析。统计和分析了相关理化性质的空间特征分布与变化趋势,洪泽湖入湖输沙量大于出湖输沙量,呈淤积状态;对洪泽湖底泥中的总氮、总磷、重金属等进行了评价,重金属大部分元素达到土壤评价二级标准,重金属污染属于重污染,与镉浓度含量超标有关。提出了防治洪泽湖底泥污染的措施。     

Job Lock in Rural versus Urban Labor Markets

While the possible negative effect of employer‐sponsored health insurance on labor mobility (job lock) has spawned substantial research, little research has considered differences in job lock between rural and urban areas. Job lock might differ in rural areas because of specific features of rural economies, in particular, the thinness of rural labor markets. This paper estimates measures of job lock for rural and urban areas. Parameter estimates suggest that it is larger in rural areas. The results also indicate that nonwage benefits such as retirement plans, paid vacation, and sick pay are more important factors in married rural workers decisions to change jobs while wages are a more important factor in the transition decisions of single urban workers.     

坡面尺度土地利用空间配置的产沙效应——以陕北黄土丘陵沟壑区为例

为了研究黄土丘陵沟壑区缓坡地土地利用与水土流失的作用机理,选取中科院安塞水土保持综合试验站9个缓坡试验小区为研究对象,分析了2009—2011年不同土地利用配置方式(谷子地、柳枝稷地、撂荒地、2/3谷子-1/3柳枝稷地、2/3谷子-1/3撂荒地)的侵蚀产沙特征及其与降雨、植被覆盖度的关系以及减沙效益。结果表明:缓坡不同土地利用配置方式的次降雨产沙量大小为谷子地>2/3谷子-1/3柳枝稷地>2/3谷子-1/3撂荒地>柳枝稷地>撂荒地,与短历时高强度降雨关系密切;7月可能是泥沙量产生的敏感时期;短历时高强度暴雨往往是年产沙量变化的主要原因;与谷子地相比,柳枝稷地、撂荒地、2/3谷子-1/3柳枝稷地、2/3谷子-1/3撂荒地均表现出不同程度的减沙效应,减沙效应大小为:撂荒地>柳枝稷地>2/3谷子-1/3撂荒地>2/3谷子-1/3柳枝稷地;植被覆盖度的提高能有效地减少产沙量。研究结果可以为缓坡土地利用对水土流失的影响评价提供一定的参考依据。     

华东地区典型县域近20年土地利用动态变化分析 —以宜兴市为例

摘要：以1987年和2007年的TM遥感图像为主要数据源,利用人工解译和监督分类相结合的方法提取宜兴市土地利用类型数据,采用GIS空间分析方法和数理统计方法分析了土地利用的数量、比例和结构变化,得到宜兴市近20年来土地利用时空变化特征。结果表明,近20年来宜兴市的土地利用总体变化趋势是耕地面积急剧下降、建设用地和水域面积都有大幅度增加、林地和园地的面积变化不大;土地利用类型之间的转移主要是水田向建设用地和水域转移,林地向园地和建设用地转移,旱地和未利用地主要是向其它地类单向转出;宜兴市20年来耕地的平均年降幅为1.76%,建设用地增长幅度的平均年增幅为4.05%,变化幅度均远超过全国平均水平。     

Accumulation rates of estuarine sediment in the dollard area: comparison of 210Pb and pollen influx methods

Profiles of excess ²¹⁰Pb activity in sediment cores collected on the muddy tidal flats of the Dollard indicate deposition rates ranging from 0.14 to 0.27 cm·y⁻¹. One profile was also analysed for pollen: the pollen profile in the core provided a record of the sedimentation rate because two independent historical events were found recorded in the profile. The first, a sudden abundance of an Aster-type pollen, reflected, at a depth of 33 cm in the sediment, the large land reclamation of 1862 A.D. The second, the appearance of Zea mays (corn) at a depth of 6 cm, reflected the increase of the area in which corn was cultivated: from 44 ha in 1970 up to 552 ha in 1973. The pollen data gave an estimated sedimentation rate of 0.25 cm·y⁻¹. Excess ²¹⁰Pb analysis of the same core yielded a sedimentation rate of 0.27 cm·y⁻¹.     

Denitrification and nitrous oxide in the North Sea

In situ sediment denitrification rates were determined in the major areas of deposition of the North Sea, using the acetylene block technique. In addition, nitrous oxide profiles of the water column were determined. Nitrous oxide production generally occurred in the photic zone possibly due to nitrification; and throughout the water column in the German Bight region. Consumption at depth was possibly due to reduction in the anoxic microzones of faecal pellets, concentrated at the thermocline. Saturation of surface waters was 102.2% compared to 130.3% in the German Bight region. Calculated flux of nitrous oxide to the atmosphere was 9.5 × 10⁶ kg yr⁻¹, over half of which was produced in the German Bight.Sediment denitrification rates varied through three orders of magnitude; the highest value of 150 μmol m⁻² d⁻¹ was recorded in the Norwegian Trench. Nitrous oxide production by the sediments was low (1.1 μmol m⁻² d⁻¹ max.), and was undetectable at half of the sites. Sediment nutrient profiles exhibited porewater nitrate concentrations exceeding that of the overlying water suggesting that denitrification was fuelled by nitrification, which, in turn was related to other environmental variables. A significant positive relationship existed between in situ denitrification rate and the nitrate content of the upper sediment. Extrapolation of the rate to the total area of deposition in the North Sea suggests that denitrification is responsible for a minimum loss of 7.5–12% of the total annual nitrogen contaminant input.     

A Shared Resource Mutually Exclusive Operation in Parallel Processing System--The Application Model of Lock Control Thechnology

It is one of the pivotal technology that mutually exclusive operation is in the system structural design of the parallel processing to solve resource conflict.Traditionally,the sharer resource mutually exclusive operation is managed by single-computer operation system time-sharing mode for multitask condition,but all of parallel nodes possess renovate right in multi-mode OS,so high-grade lock mechanism is a pivotal technology to solve share resource confilict in parallel process to prevent share resource accessing conflict.This article describes lock control arithmetic of mutually exclusive operation from system structure and puts forward mutually exclusive operation model based on NODS.