城市区域近地表灰尘及重金属沉降垂向季节变化

随着城市高层建筑的出现,人类日常生活的垂向空间范围逐渐向上延伸,近地表灰尘及重金属沉降垂向分布的季节特征值得关注.本研究分别在春、夏、秋、冬四季采集贵阳市某生活-文教区近地表不同空间高度平台上的灰尘样品,分析灰尘沉降通量及灰尘中Ca、Fe、Cd、Cr、Cu、Ni、Pb和Zn含量,探讨灰尘沉降通量及元素含量随空间高度的变化,揭示区域近地表灰尘及重金属沉降垂向分布的季节变化特征.结果表明,空间高度灰尘沉降通量季节变化总体上表现为冬季灰尘沉降通量最大,春季次之,夏季最低;冬季灰尘沉降通量沿垂向空间高度的分布差异最大,其次是夏季,春秋两季灰尘沉降通量垂向空间差异较小;季节变化对低层空间平台灰尘沉降通量影响大于高层空间;春季灰尘中元素含量最高,秋季灰尘重元素含量相对较低;元素含量随时空变化最大的是Zn,变化较小的是Ca.冬、春季节大气逆温层可能是灰尘沉降量和Pb、Zn等元素含量升高的原因之一.     

南京夏季城市冠层大气 CO2浓度时空分布规律的观测

城市是CO2重要排放源,直接观测城市中大气CO2浓度对于研究人类活动对大气温室气体的贡献至关重要,而在城市中多个站点、多个高度上观测大气CO2浓度则有助于认识城市CO2浓度的时空变化规律,确定其影响机制.本研究于2014年7月18日至7月25日在南京主城区东、西、南、北和中共5个方位(100 m左右高度),2014年8月3日至2014年8月9日在南京主城区中部站点的3个高度(30、65和110 m)观测CO2浓度.结果表明:1南京主城区垂直方向上CO2浓度存在明显梯度,近地面30 m处CO2浓度受人为活动影响明显,平均值达427.3×10-6(±18.2×10-6)(摩尔分数,下同),高层65m、110 m处CO2浓度混合均匀,平均值分别为411.8×10-6(±15.0×10-6)和410.9×10-6(±14.6×10-6).大气层结越稳定,CO2浓度越高,垂直梯度越大.2南京主城区CO2浓度的水平分布受风和大气稳定度的控制.观测期间盛行东北风向,导致CO2浓度分布整体呈现西南高,东北低的格局,城市主城区上下风向CO2浓度差为7.8×10-6.而且水平风速越大,越有助于将上风向的CO2传输至城市的下风向,CO2浓度差就越小.大气层结越稳定,整体CO2浓度越高.3南京主城区5个站点CO2浓度均有明显的日变化,日最高值出现在交通早高峰期间,谷值在17:00左右,在19:00左右有时会因交通晚高峰而出现次高值.     

水库岸坡变形体灾害的信息评价和预测

较真实地评价水库岸坡的稳定性是工程界普遍关注的问题,本文将工程地质逻辑定性分析和信息法定量分析方法结合起来,对丹江口水库库岸岸坡变形体灾害的信息进行评价和预测,分析结果可供工程设计人员参考。     

常熟定点形变对江苏及南黄海中强震映震能力及预报效能分析

采用地形变前兆特征研究中的多种方法,利用常熟台定点形变观测资料,对自1985 年以来发生在江苏省及南黄海海域的中强地震进行了研究及观测手段的映震能力检验,得出:(1) 常熟地倾斜对其周围200 km 范围内MS≥4-5 地震有较好的中、短期前兆异常显示;(2) 归纳总结各分析方法判别获得的异常表明,常熟地倾斜单台信度较高,具有较强的映震能力。     

DESALTING SALINE WATER FOR IRRIGATION A CASE STUDY,COACHELLA AREA,CALIFORNIA1

ABSTRACT .A case study was performed to evaluate potential applications of desalted saline water for agriculture using 2 distillation type processes and 2 membrane type processes. The investigation determined the costs and benefits associated with desalting saline water at concentrations of 1,500, 900, 400, 200, and 50 ppm. Benefits from desalting are generated by shifts to more profitable crops, reduced costs for drainage, and reduction in fertilizer and labor requirements with better quality water. Costs are based on the project features such as desalting plants, raw water diversion facilities, storage reservoirs, conveyance and distribution systems, brine disposal, blending facilities, and gypsum addition systems. Hydrologic studies determined the crop irrigation requirements, water demand schedules, desalted water storage requirements, brine disposal requirements, and size of facilities required. Reconnaissance design layouts were made for producing desalted water using a combination of 14 schemes. The study also included a review of irrigation practices. The benefit-cost ratios range from 0.4 to 1.0 for 1,500 ppm irrigation water to 0.8 to 1.0 for 50 and 200 ppm water. Investment costs per acre are high, ranging from $12,900 to $20,900. Irrigation benefits are based on the increase in production from a desert condition with no water supply to the irrigation conditions studied.     

川东平行岭谷区自然景观垂直分异规律及综合分区--以重庆北碚区为例

以重庆市北碚区为代表,论述了川东平行岭谷区自然景观的垂直分异特征,并在此基础上对该区域进行了综合分区,再结合各分区内土地的自然特征采取不同的措施,从而做到因地制宜地发展各项生产.     

Heterogeneous Traffic Induced Effects on Vertical Dispersion Parameter in the Near Field of Roadways - a Wind Tunnel Study

The varying traffic parameters such as traffic volume, speed, shape and size, and terrain roughness conditions play a vital role on dispersion of pollutants in the near field of roadways. Simulation experiments were carried out in the Environmental Wind Tunnel (EWT) to evaluate the traffic induced effects on vertical dispersion parameter (σ _z ) for heterogeneous traffic conditions in the near field of roadways for evaluating the effect of variations in traffic volume, terrain roughness condition and approaching wind direction. The model vehicle movement system was fabricated and made operational in the EWT, which allowed the variation in traffic volume, speed and wind road inclination. Sixty-six hydrocarbon tracer experiments were performed to evaluate σ _z in the near field of roadways for variable traffic volume, three terrain roughness conditions and two approaching wind directions (i.e., 90° and 60°). The values of σ _z for heterogeneous traffic conditions were found to be higher for low roughness conditions in comparison to other two higher roughness conditions for various traffic volumes and approaching wind directions. This revised version was published online in July 2006 with corrections to the Cover Date.     

长乐—南澳变质带显微构造和岩组特征及应力场分析

通过光学显微镜和高压电子显微镜对带内的变形石英进行显微构造超微构造观测和估算变形参数(σ_1-σ_3=85.0MPa,ε_s=10~(-9)～10~(-10)/S),认为该区变质岩形成于深层环境,是长期缓慢变形的结果。变形石英位错构造为变形阶段和恢复阶段的混合体,其变形机制为塑性形变。采用石英光轴干涉图法,在偏光显微镜下对水平定向薄片进行岩组测量,绘制成该区的石英光轴方位图,探讨其构造变形的演化历史。首次划分出S(或S+S)和B+S构造岩岩组类型及Ⅰ型、Ⅳ型和Ⅴ型石英定向类型。应力场随着构造变形的演化作逆时针旋转。山南北挤压应力场逐渐变为单向推挤的应力场,从而认为构造变形是多期次的叠加。     

钢轨接头轨缝值和行车速度对轮轨垂向振动的影响

为了分析轨缝值与行车速度对车辆通过钢轨接头时产生的振动与噪声的影响程度,利用有限元方法,建立了车辆—轨道垂向耦合动力计算模型;该模型的车辆采用整车模型,共10个自由度;轨道结构采用3层弹性点支承有限长欧拉梁模型,共402个自由度;系统的激励大小可由轨缝值和行车速度推导出来,并运用赫兹非线性接触理论计算轮轨之间的相互作用力。采用该模型,结合快速显式迭代积分法和MATLAB6.5强大的矩阵分析功能,对不同轨缝值和车辆行驶速度条件下钢轨接头的动力响应进行了计算,为减振降噪提供理论依据。     

锅炉水冷壁大面积变形原因分析

分析了锦山电厂2^#锅炉水冷壁管大面积变形的原因，介绍了水冷壁变形的处理办法及留下的思考。