分层异重流对香溪河浮游植物叶绿素a空间分布的影响

基于三峡水库香溪河库湾汛期（2017年8月4—10日）水动力、气象和藻类漂移监测数据,运用数理统计方法,分析汛期香溪河浮游植物叶绿素a（Chla）浓度空间分布特征及其影响因素,探究分层异重流背景下藻类的水平输移和垂向掺混作用过程。结果表明：1)汛期香溪河库湾水动力具有明显的分层异重流特性,监测期间雷诺数均大于4 000,水体呈现紊流状态,对藻类的运动输移产生水平输运和垂向掺混2种影响。2)表层藻类水平漂移速度受到风速和水流流速的影响,响应关系式为V_藻=0.035V_风+0.461V_水+0.034 (R²=0.917,P<0.01)。3)分层异重流对高浓度藻细胞库湾原水的稀释作用和环流对高浓度藻细胞的携带作用,导致水柱Chla总浓度呈直线下降趋势,此时干流水体从中上层倒灌进库湾,上游来水以底部顺坡异重流方式流向河口,在中上游相遇形成环流,在库湾中部倒灌水体一分为二,分别从底部和表层输出库湾,Chla浓度分布特征为表层>底层>中层;当倒灌水体与库湾原水形成环流并从底部输出库湾时,Chla浓度分布特征为表层>中层>底层或者中层>底层>表层。因此,Chla浓度的水平分布主要受到风速和异重流的水平流速的影响,而垂向分布受到异重流所形成的水体循环模式的影响。     

卧式电除尘器电晕极优化实验研究

运用粉尘粒子荷电原理,对四种电晕极的主要技术性能进行了试验研究,探讨了卧式电除尘器的最佳极配形式。     

基于BP神经网络不同输入变量的爆破振速预测

以某隧道爆破开挖为实例,利用BP神经网络解决复杂非线性函数逼近问题的能力,以最大段药量、爆心距、爆破分段数、泊松比、岩石基本质量指标作为影响爆破振动速度的主要因素,选取不同维数的输入变量建立BP神经网络模型来预测爆破振动速度。对比分析各组预测值与实测值之间的相对误差,选取合理维数的输入变量建立了爆破振动危害预测的BP神经网络模型。     

分岔隧道火灾火源位置对临界风速影响的数值模拟分析

为探究分岔隧道火灾火源位置对临界风速的影响规律,使用数值模拟方法对火源位于分岔隧道分岔口前和分岔口后的火灾场景下的临界风速进行研究.研究结果表明:火源位于分岔口后的主隧道时,临界风速明显大于火源位于分岔口前的临界风速;在一定范围热释放速率下,分岔隧道临界风速与热释放速率的1/3次方成正比;在分岔隧道模型中,相同热释放速...     

Phosphorus Load Reduction Goals for Feitsui Reservoir Watershed, Taiwan

The present paper describes an effort for developing the total maximum daily load (TMDL) for phosphorus and a load reduction strategy for the Feitsui Reservoir in Northern Taiwan. BASINS model was employed to estimate watershed pollutant loads from nonpoint sources (NPS) in the Feitsui Reservoir watershed. The BASINS model was calibrated using field data collected during a 2-year sampling period and then used to compute watershed pollutant loadings into the Feitsui Reservoir. The simulated results indicate that the average annual total phosphorus (TP) loading into the reservoir is 18,910 kg/year, which consists of non-point source loading of 16,003 kg/year, and point source loading of 2,907 kg/year. The Vollenweider mass balance model was used next to determine the degree of eutrophication under current pollutant loading and the load reduction needed to keep the reservoir from being eutrophic. It was estimated that Feitsui Reservoir can becoming of the oligotrophic state if the average annual TP loading is reduced by 37% or more. The results provide the basis on which an integrated control action plan for both point and nonpoint sources of pollution in the watershed can be developed.     

高温条件下高速碰撞试验技术研究

目的建立高温条件下结构的高速碰撞试验技术。方法基于理论和试验方法,研究影响试样加热/保温、碰靶速度和姿态的关键因素,利用次口径发射技术和电炉技术实现试样的加热、保温和加速。采用间接方法测试试样碰靶时的温度,联合应用次口径发射技术和靶体,控制试样的碰靶姿态,并利用高速摄影技术对其进行测试。通过薄壁圆柱筒的高温高速碰靶验证高温试验技术的有效性。结果建立了加热、加速和姿态控制一体化的高温高速碰撞试验技术,获得了不同尺寸薄壁圆柱筒不同姿态碰靶时的高温冲击动力学响应。正碰时,撞击端镦粗,尾端收缩,尾端的凹陷大于碰撞端的变形;侧碰时,圆筒呈马鞍状;角碰时的变形为楔形。随着圆筒的强度和刚度的降低,圆筒的变形增加,整体发生坍塌,出现大量的皱褶。结论建立的试验技术切实有效,可以用于高温条件下结构高速碰撞效应的研究。     

柱型水力旋流器对硅切割废砂浆分离性能的研究

为了研究废砂浆中碳化硅粉和硅粉的分离情况,选用混合模型对柱型水力旋流器多相流流场进行数值模拟。模拟结果表明:柱型水力旋流器的分离效率与入口速度、进口浓度等因素有关,并分析出一定条件下当主、次相的入口速度均为1.1m/s时颗粒分离效果较好,分离效率较高,实验检测分离性能较好,为进一步实验研究提供一定的指导。     

一种富稀土型三效催化剂的性能考察

对一种富烯土型三效催化剂的性能进行了考察，结果表明：该催化剂具有较好的三效活性和较好的启燃温度特性，具有较宛的空速适应范围，在空速为84000h^-1时，CO,NOx的转化率仍在90％以上，HC转化率仍在70％以上，该催化剂具有较好的耐老化性能，经实验室快速老化实验，即相当于实车行驶8万km,CO劣化系数，1.09,HC劣化系1．05，NOx劣化系数1．06，该催化剂经桑塔纳轿车整车28工况测试，其交化效果与该车配置的美国Engelherd公司的催化剂相当。     

Dry deposition velocity of total suspended particles and meteorological influence in four locations in Guangzhou, China

Dry deposition velocity of total suspended particles (TSP) is an effective parameter that describes the speed of atmospheric particulate matter deposit to the natural surface. It is also an important indicator to the capacity of atmosphere self-depuration. However, the spatial and temporal variations in dry deposition velocity of TSP at different urban landscapes and the relationship between dry deposition velocity and the meteorological parameters are subject to large uncertainties. We concurrently investigated this relationship at four different landscapes of Guangzhou, from October to December of 2009. The result of the average dry deposition velocity is (1.49 ± 0.77), (1.44 ± 0.77), (1.13 ± 0.53) and (1.82 ± 0.82) cm/sec for urban commercial landscape, urban forest landscape, urban residential landscape and country landscape, respectively. This spatial variation can be explained by the difference of both particle size composition of TSP and meteorological parameters of sampling sites. Dry deposition velocity of TSP has a positive correlation with wind speed, and a negative correlation with temperature and relative humidity. Wind speed is the strongest factor that affects the magnitude of TSP dry deposition velocity, and the temperature is another considerable strong meteorological factor.We also find out that the relative humidity brings less impact, especially during the dry season. It is thus implied that the current global warming and urban heat island effect may lead to correlative changes in TSP dry deposition velocity, especially in the urban areas.     

深度平均的应力-通量代数全场模型及其验证

提出了深度平均的应力—通量代数全场模型，用来模拟热水侧向排入大水体的各向异性的输移扩散规律。应用有限体积法对控制方程进行离散，利用ＳＩＭＰＬＥ法进行数值模拟。通过该模式的模拟计算给出了速度场、温度场的分布。所得的回流区形状及温度场分布与深度平均的ｋ－ε模型及实验资料对比，本文的计算结果与实测值符合得较好