农田排水中氮磷监测规范化技术

在对农业面源污染的调查和研究中,氮磷浓度水平的确定至关重要。阐述了农田排水中氮磷样品采集的方法和注意事项,样品的保存、运输和预处理技术,以及分析方法和实验室质量控制,为农田排水中氮磷监测的规范化技术提供参考。     

Estimate of sediment yield in a basin without sediment data

In this study, three mathematical models for the estimate of sediment yield, due to soil and stream erosion, at the outlet of a basin are presented. Each model consists of three submodels: a rainfall-runoff submodel, a soil erosion submodel and a sediment transport submodel for streams. The rainfall-runoff and the stream sediment transport submodels are identical in the three mathematical models. The rainfall-runoff submodel that is used for the computation of the runoff in a sub-basin is a simplified water balance model for the soil root zone. For the estimate of soil erosion in a sub-basin, three different submodels are used alternatively, owing to the fact that erosion or sediment yield data are not available. The soil erosion submodels are (a) a modified form of the classical Universal Soil Loss Equation (USLE, [Foster, G.R., Meyer, L.D., Onstad, C.A., 1977. A runoff erosivity factor and variable slope length exponents for soil loss estimates. Transactions of the ASAE, 20 (4), 683–687]) taking into account both the rainfall erosion and the runoff erosion, (b) the relationships of Poesen [Poesen, J., 1985. An improved splash transport model. Zeitschrift für Geomorphologie, 29, 193–211] quantifying the splash detachment, as well as the upslope and downslope splash transport, (c) the relationships of Schmidt [Schmidt, J., 1992. Predicting the sediment yield from agricultural land using a new soil erosion model. Proceedings of the 5th International Symposium on River Sedimentation. Karlsruhe, Germany, pp. 1045–1051] including the momentum flux exerted by the droplets and the momentum flux exerted by the runoff. The sediment transport submodel for streams aims to estimate the sediment yield at the outlet of a sub-basin. This quantity results by comparing the available sediment amount in the main stream of a sub-basin with the sediment transport capacity by stream flow, which is computed by the relationships of Yang and Stall [Yang, C.T., Stall, J.B., 1976. Applicability of unit stream power equation. Journal of the Hydraulics Division, ASCE, 102, 559–568]. The mathematical models were applied to the basin of Kompsatos River, in northeastern Greece, with an area of about 565 km². The whole basin was divided into 18 natural sub-basins for more precise calculations. Monthly rainfall data were available for 27 years (1966–1992); therefore, the calculations were performed on a monthly basis. The deviation between the three mean annual values of sediment yield at the basin outlet, for 27 years, resulting from the three mathematical models is relatively small.     

Study on the New Technology of Extracting PD in Strong Noise Environment With Complex Wavelet

Based on existing research, this paper analyzes and compares the phase information characters between partial discharge signal (PD) and its disturbance, and also extracts the feature of Partial Discharge with complex wavelets in noise environment. The research demonstrates that complex wavelets are more superior to original real wavelets in identifying Partial Discharge signal, and those simulated applications and the datum from laboratory can guarantee the effectiveness of the extraction of the feature of Partial Discharge and the restraint of the strong electromagnetic disturbance.     

提水泵站空流段流量配合问题探讨

通过对水泵性能差异引起的水泵出水量的变化分析,提出了调节级间流量差的小机组流量的确定方法,解决了多级提水泵站空流段的级间流量配合问题。     

塔里木河流域水土流失动态变化分析

研究塔里木河流域土地利用变化、年径流量和输沙量变化特征及其相关关系，以期促进水土资源的合理开发和利用，为塔里木河流域的生态环境治理提供科学依据。水文数据为2005-2020年流域焉耆站、同古孜洛克站、卡群站、西大桥站、阿拉尔站年径流量、年输沙量，土地利用数据为1980-2015年土地利用空间分布数据。结果表明：（1）1980-2015年，土地利用面积比例变化为-1.07%~1.16%，耕地面积增幅为1.16%，沙地面积增幅0.30%，草地面积降幅1.07%；（2）流域内各主要河流多年平均径流量为22.99×108~67.46×108 m3，多年平均输沙量63.20×104~3070.00×104t；开都河多年平均含沙量为0.24 kg/m3，其余河流平均含沙量均大于4kg/m3；塔里木河流域年径流量和年输沙量均呈现下降变化趋势，且年输沙量的变异性（40.89%~73.11%）大于年径流量（15.54%~35.37%）；（3）各主要河流的年径流量、年输沙量与耕地和城乡居民用地的占比均呈负相关关系，与林地、草地、沙地等均呈现正相关关系。建议合理进行土地开发，禁止盲目开荒种田，充分运用智能化手段开展在线动态监测，及时掌握水土流失情况，恢复和重建塔里木河流域生态。     

大泵肘形进水流道过水断面的分析与应用

分析了大型立式轴流泵站时形进水流道实际过水断面的空间形状。用介于实际过水断面和平均过水断面之间的一种过水断面─—柱面论证了《泵站技术规范》中肘形进水流道使用平均过水断面的可行性。从工程实用性角度提出“近似过水断面”的设计思想，用解析的方法给出其数学模型；同ＡｕｔｏＣＡＤ绘图软件接口给出其输出结果。为证明其可行性，又将其与规范规定的平均过水断面的变化规律作了比较，结果令人满意。     

塔克拉玛干沙漠北缘荒漠过渡带风沙流结构特征分析

利用多种集沙仪,通过野外实时输沙观测,对塔克拉玛干沙漠北缘荒漠过渡带的地表风沙流特征进行了分析,结果表明：① 100 cm高度范围内,总输沙量的47.3%分布在30 cm高度内,这一比例小于前人的研究结果;输沙量随高度的变化比较符合幂函数分布。② 风沙流输沙的粒径以细砂、极细砂与粉砂为主,各高度层所占比例均达99%以上;风沙流输沙平均粒径随高度增加而减小,沙尘的含量随高度增加呈现“象鼻”状分布。③ 风沙流中贴地层风速廓线受风沙相互作用的影响,不再符合对数分布,更加符合幂函数u=az^b分布。     

策勒绿洲-荒漠过渡带风沙前沿近地面不同方向的输沙特征

利用策勒绿洲-荒漠过渡带风沙前沿输沙资料及风速风向资料,分析这一区域近地面输沙的方向分布特征。结果表明：① 风沙前沿起沙风风向以W、WNW为主,风向变化比较单一;② 观测点输沙量集中于NW、WNW、W、SW、WSW 5个方位,合计占总输沙量的68.3%;0～40 cm高度年输沙量为96.0 kg,年合成输沙量为45.9 kg,合成输沙方向为102.5°;③ 观测点年输沙势为43.2 VU,年合成输沙势为31.04 VU,输沙势的方向分布与实测输沙量存在较大差异。     

高压静电灭虫器的设计与试验

【目的】研制高压静电灭虫器,为实现高压静电杀灭农作物害虫提供新的装置。【方法】研制10～60 kV可调高压静电灭虫器,以茶树害虫茶尺蠖和茶小绿叶蝉为杀灭对象,对其杀虫效果进行检测,并对高压静电灭虫器的放电特性及不同电压下其对植物的影响进行分析。【结果】当电极直径为0.5 mm、电极间距为40 mm、使用电压为30～50 kV、击穿距离取25～30 mm时,研制出的高压静电灭虫器对茶小绿叶蝉的防治效果为2.3%～12.8%,对茶尺蠖的防治效果为64.3%～71.1%。高压静电灭虫器的放电电压上升至30 kV以上时,在设定距离内能稳定持续放电,且随着电压上升,放电强度增强。高压静电灭虫器的电压设定为30 kV时,扫过茶树植株幼芽2～3 s,对茶树植株幼芽叶片杀伤无明显影响;当高压静电灭虫器的电压上升至40 kV时,对幼芽有轻微影响,有枯萎但能恢复;当电压上升至50 kV时,幼芽枯萎,不能恢复。当高压静电灭虫器扫过茶树植株幼芽的时间降为1～2 s时,50 kV电压下其对幼芽造成的枯萎可恢复。【结论】成功研制了一种高压静电灭虫器,其对茶树植株害虫茶尺蠖有明显的杀灭作用。     

浅谈无缝线路施工工艺

采用无缝线路技术在地铁中施工,能够使轨道的几何形态更加平顺,大大的增加了列车的行车速度,也减少了轨道对列车的磨损和轨道自身的磨损,为正式营运后的维修和保养节约大量的资金,由于此优势,乘客的乘车舒适感大大增加,也解决了有缝线路轨道间错台大,导致噪音大及列车出轨事故的技术难题,因此,无缝线路轨道以其低噪声、低维修率、高平顺性成为城市轨道交通中轨道结构的首选。