A Review of Artificial Waterfalls in Gardens

When artificial waterfalls are built in gardens,leaves from trees or vegetation often fall into the water storage pool and block the pipelines,requiring regular cleaning of pipelines.This not only increases the manpower needed for maintenance but also disrupts the use of the waterfalls.Therefore,it is necessary to design a new type of artificial waterfall that is suitable for gardens.The waterfall should incorporate features that make cleaning easier,including filter plates and water funnels to prevent clogging caused by fallen leaves and debris.

Huangguoshu Waterfall

Have you ever been to Huangguoshu Waterfall?It is said to be No.1 waterfall in Asia.It lies in Guizhou Province and is one of the most famous place1for sightseeing.Every year,millions of people will come2to visit it.The great waterfall is 77.8 meters high and 101 meters wide.But if you went to the waterfall in spring in 2010,you would find a different water-

Water Self-Softening Processes at Waterfall Sites

Many rivers in tropical and subtropical karst regions are supersaturated with respect to CaCO3 and have high water hardness. After flowing through waterfall sites, river water is usually softened, accompanied by tufa formation, which is simply described as a result of water turbulence in fast-flowing water. In this paper, a series of laboratory experiments are designed to simulate the hydrological conditions at waterfall sites. The influences of air-water interface, water flow velocity, aeration and solid-water interface on water softening are compared and evaluated on a quantitative basis. The results show that the enhanced inorganic CO2 outgassing due to sudden hydrological changes occurring at waterfall sites is the principal cause of water softening at waterfall sites. Both air-water interface area and water flow velocity increase as a result of the 'aeration effect', 'low pressure effect' and 'jet-flow effect' at waterfall sites, which greatly accelerates CO2 outgassing and therefore makes natural waters become highly supersaturated with respect to CaCO3, consequently resulting in much CaCO3 deposition and reduction of water hardness. Aeration, rapidly increasing air-water interface area and water flow velocity, proves to be effective in reducing water hardness. This study may provide a cheap, safe and effective way to soften water.

Regional- to local-scale controls on waterfalls in Rocky Mountain National Park,Colorado

Previous work on the eastern side of Rocky Mountain National Park(RMNP),Colorado indicated correlations among waterfall location,waterfall morphology,and the characteristics of bedrock joints.Characteristics of waterfalls on the western side of the national park do not correlate as strongly with joint geometry.Longitudinal river profiles on the western side are less concave and waterfalls account for a greater proportion of the total elevation loss.We interpret these differences to result from more widely spaced joints,lithological differences,and complex glacial history.These results demonstrate that waterfall shape and typology may change due to both local and regional controls operating in a mountain region.Both regions had alpine valley glaciers,but continued landscape evolution via fluvial erosion has developed waterfalls with diverse locations and morphologies that reflect the influences of glacial deposits,bedrock erosional resistance,and joint geometry.

Fishery and the Tourism Potential of Agbokum Waterfalls, Nigeria

Species richness and human activities in natural environments are among the most important recreational needs. Monthly studies of aquatic fauna, artisanal fisheries and tourism characteristics was conducted during wet and dry seasons, over a two year period in the three landscapes along the 6817.7 m length of Agbokum waterfalls by using a close-ended pre-coded survey instrument. Through MANOVA analysis of the 1780 respondents we found strong positive association between peoples visits to the recreational areas and the type of landscape in which the respondents felt happy. People who felt happier in landscape dominated by waterfalls, visit the middle reaches of the river for outdoor recreation more often while people who feel happy in landscapes dominated by slow water current with an extensive wide area and floodplains, visit downstream reaches of the waterfalls more often. Activities performed more often along downstream reaches include fishing, bathing/swimming, boating and hunting while more frequent activities in the middle reaches (waterfalls) include taking photographs, picnics, enjoying nature, outing with family and friends, looking at view, resting and relaxing. A total of 5484 fish representing 22 species belonging to 16 genera from 9 families were sampled with 10 species being restricted to wet season and only 1 in the dry. The number of taxa and individuals present at upstream, midstream and downstream reaches were 16 (2003), 13 (1034), 17 (2447), respectively. Tilapia zillii, Clarias gariepinus and Labeo coubie dominated overall catch constituting 35.5%. Twenty five operational boats counted during the period of study, were only used downstream by 25 full-time fishermen, 87 part-time, 44 shoreline fishermen and 36 assistant fishermen. Common gears were the hook and line constituting 45.8%, cast and dip net (10.1%) bailing (8.7%), gill nets (7.3%), seine net (6.4%) Traps (5.5%), lift net (4.7%) Dip nets (0.9%), poisoning (2.8%), cutlass (3.3%) and spear (1%). Seasonally occurring aquatic fauna include crustaceans (Atya gaboneensis and Palaemon paucidens) (23.5%) oysters (Etheria elliptica) (15.4%), clams (Galacea paradoxa) (20.8%), Manatee (Trichechus senegalensis) (2.5), Hippopotamus amphibious (1.8%), Otter (Lutra macullicolis) (0.5%), Crocodyles (Crocodylus niloticus, Crocodylus cataphractus (Aligata) and Osteolaemus tetraspsis) (18.8%). The nile monitor (Varanus nilaticus), aquatic snake (Anoscopus sp), and three species of water turtle (Kimxys erosa, Pelumedusa sp and Peliosus sp) (21.6%). Relatively higher faunal densities and species richness in the upstream and downstream reaches coupled with waterfalls in middle reaches can makes Agbokum waterfalls a tourism destination if only management strategies include Legislation to conserve these natural resources.

Landscape Formation and Protection of the Hukou Waterfall

Establishing geoparks is an effective approach to protect natural resources and promote local tourism industry. The national geopark of the Hukou Waterfall is an important geopark which attracts more than 2 million tourists per year. The Hukou Waterfall is formed by combination of multiple knickpoints due to the longitudinal profile analysis. Like other waterfalls in the world, the Hukou Waterfall will disappear in the future. Considering the mechanisms of waterfall evolution, this paper suggests establishing control engineering, preserving the water and soil in nearby region, and reinforcing the structure of waterfall to preserve the landscape of waterfall.

Basic Characteristics of Waterfalls in the Yarlung Zangbo River

The Great Bent in the lower reaches of the Yarlung Zangbo River in Tibet houses the largest fluvial gorge in the world. On October 18, 1998, the Chinese government named the gorge the Grand Canyon of the Yarlung Zangbo. Later, from October to December, the first trekking exploration through the canyon was successfully conducted by a group of Chinese scientists. In the meantime, the scientists carfled out a multi-disciplinary and comprehensive survey and made many discoveries in the region.

Numerical Prediction and Analysis of Hydraulic Characteristics of Waterfall Scene for Application to Design Control

The hydraulic characteristics of artificial waterfalls constitute an important research area for both academia and industry. As yet, the hydraulic parameters used in the hydraulic design of landscape waterfalls are not well understood for use in qualitative and quantitative analyses. Due to their complicated shapes and appearances, it remains a challenging problem to design or simulate realistic waterfall scenes. In this paper, we present a hybrid model and an efficient numerical method for simulating the hydraulic characteristics of waterfalls and investigate the critical flow in waterfall design and the adherent flow phenomenon. We fit empirical equations to predict the size and shape of different waterfall flow patterns to provide a basis for the design and construction of waterscapes in the real world. We then apply our work to an artificial waterfall in Kraal Jiang River and the results demonstrate that our model achieves desirable control qualities and good agreement in a real-world application. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg.

襄阳东站钢屋盖超多杆连接节点设计与足尺模型试验研究

襄阳东站屋盖南北向长358m,东西向最大跨度86m,采用焊接球钢网架,整体不设变形缝,南端开设瀑布造型大洞口,由于屋盖结构超长、不连续、大悬挑及瀑布造型使得钢屋盖空间受力十分复杂,特在分叉柱柱顶沿南北向设置加强杆以加强屋盖瀑布区洞口两侧边缘约束刚度及改善结构整体受力性能。钢屋盖瀑布区悬挑端分叉柱柱顶节点相连杆件达12根之多,该节点作为屋盖结构的关键节点,其受力状态尤为复杂,创新地采用了半铸造半相贯焊连接形式并采取了构造加强措施,针对该超多杆连接节点进行了足尺模型加载试验验证,详细介绍了试验加载装置、加载方案、试验现象及试验结果,并进行了有限元对比分析。结果表明有限元对比分析结果与加载试验吻合较好;该超多杆半铸造半相贯焊连接节点构造合理、承载力高,薄弱部位出现在与铸造本体相连的接长钢管上,满足强节点弱构件、强连接弱构件的设计要求。

基于深度学习的互联网接收机中特定信号识别

随着软件无线电技术和互联网技术的发展,有大量的互联网接收机接入互联网,并可任意访问其频谱瀑布图数据。频谱瀑布图是信号频域和时域特性的一种展示方式,将不同频率的信号以图像的方式直观地进行展示,为了更好地监测到频谱瀑布图中的特定信号,需要对频谱瀑布图中的特定信号进行智能识别。通过深度学习技术实现了对频谱瀑布图中特定信号识别,在信噪比大于5 dB时,识别准确率大于90%。

ST-T段改变患者心电瀑布图形态特征及其对心血管疾病的预测价值

目的探讨究ST-T段改变患者心电瀑布图形态特征及其对心血管疾病的预测价值。方法选择2020年6月1日至2022年6月1日在该院进行心电瀑布图及传统心电图检查的疑似心脏病患者970例作为研究对象,根据24 h动态心电图分为ST-T段改变216例及正常心电图754例。分析心电图ST段下降、ST段抬高、T波低平、T波负向、T波正向、T波双向波长中心电瀑布图形态特征;采用一致性检验法检测心电瀑布图、常规心电图与24 h动态心电图诊断ST-T段改变的一致性;采用四格表法检测心电瀑布图、常规心电图诊断ST-T段改变的灵敏度、特异度。结果正常心电图受检者心电图波及波群TP带、P峰带、PR峰、QPS带、ST带、T峰带、TP带心电瀑布图特征主要表现浅蓝色、亮蓝色、蓝色、红色/黄色/橙色、蓝色、蓝色/亮蓝色、浅蓝色。216例ST-T段改变患者中,156例患者心电图显示为ST段下降,其中68例患者为T波负向,心电瀑布图表现为深蓝色62例(91.18%)、蓝黑色6例(8.82%);73例患者为T波正向,心电瀑布图表现为蓝黑色66例(90.41%)、深蓝色7例(9.59%)。60例患者心电图显示为ST段抬高,其中51例患者为T波正向,心电瀑布图表现为亮蓝色43例(84.31%)、深蓝色6例(11.76%)、淡黄色2例(3.92%)。74例患者存在T波负向,心电瀑布图表现为蓝黑色;124例患者存在T波正向,心电瀑布图随T波幅度呈浅蓝-亮蓝-黄-红改变;12例存在T波低平,心电瀑布图上方随T波幅度呈浅蓝-亮蓝-黄-红改变,下方主要表现为蓝黑色。心电瀑布图诊断ST-T段改变的灵敏度、特异度、准确度分别为96.30%、88.73%、90.41%,常规心电图诊断ST-T段改变的灵敏度、特异度、准确度分别为83.33%、72.68%、75.05%。一致性检验结果显示,心电瀑布图与24 h动态心电图诊断ST-T段改变的一致性极强,常规心电图与24 h动态心电图诊断ST-T段改变的一致性较好。结论ST-T改变患者心电瀑布图具有明显特征性改变,其在诊断心血管疾病方面的价值优于常规心电图,可推广应用。

可信软件混合开发模型

为满足可信软件开发的效率和质量要求,同时保证可信软件的安全性和可靠性,提出混合开发模型。该模型将瀑布模型和敏捷模型结合,在短时间内交付软件,同时满足特定的安全级别要求。相关案例验证了该模型能够有效满足开发需求。

心电瀑布图在快速识别病态窦房结综合征各种逸搏心律中的应用

目的探讨房性、室性、交界性逸搏心律的心电瀑布图特征,为快速分析病态窦房结综合征(sick sinus syndrome,SSS)等缓慢性心律失常的动态心电图奠定基础。方法选择合并有上述三种逸搏心律的SSS病例,在常规观察其心电散点图的基础上,进一步分析其心电瀑布图特征;结合心电瀑布图的逆向技术,分析和总结三种逸搏心律的心电瀑布图特征及其与相应心电图的对应关系。结果SSS患者在窦房阻滞或窦性停搏的背景下出现的这三种保护性逸搏心律(房性、室性、交界性逸搏心律)的频率接近,相互竞争、反复交替,其心电散点图、RR间期直方图等常用分析工具揭示的特征不明显,但各种心律的心电瀑布图却特征各异,为快速分析此类病例提供了捷径。正常窦性心律的R峰带水平居中,宽度小于120 ms,色谱代表QRS波群的高度;P峰带、T峰带平行分居于R峰带上下,宽度与色谱分别代表P波、T波的时限和极性。窦性心律的三峰带心电瀑布图宽度、色谱若有变化,则意味着节律变换,其中房性逸搏心律的心电瀑布图特征为P峰带变色,R峰带、T峰带正常;室性逸搏心律的心电瀑布图特征为P峰带消失,R峰带变宽变色、T峰带变色;交界性逸搏心律的心电瀑布图特征为P峰带消失,R峰带、T峰带正常。结论心电瀑布图可用于快速识别SSS患者中的各类逸搏心律,在心电大据分析中能弥补心电散点图及RR间期直方图的不足。

一种面向在轨服务卫星地面应用系统的软件开发方法

为解决现有在轨服务卫星地面应用系统瀑布式软件开发模型灵活性差,难以适应用户需求变化等不足,通过利用敏捷开发模型的思路,设计了一种迭代式在轨服务卫星地面应用系统软件开发方法,将用户纳入到软件开发过程中,在各个研制阶段持续与用户进行需求迭代,完成业务软件的功能升级。结果表明:该方法可提升业务软件功能与用户需求的匹配程度,并为后续在轨服务卫星地面应用系统的建设提供参考。

基于改进高分辨率网络的人体姿态估计

为实现更精准的人体关键点定位,以高分辨率检测网络(HRNet)为基线引入瀑布式空洞空间卷积模块与Transformer的人体姿态估计模型和算法。首先,构建瀑布式空洞空间卷积模块替换HRNet的第4阶段,减少不同尺度特征相互融合导致参数量过大的问题,并更高效地提取多尺度特征;其次,引入基于自注意力机制的Transformer对提取的高层特征进行处理,通过捕获全局空间中关键点的非局部交互关系以获取全局信息实现特征增强。实验表明,当输入图像分辨率为256×192时,所提模型相较于HRNet-W32和HRNet-W48基线模型,在参数量下降的情况下AP分别提升2.4%、2.3%。

污水处理厂反硝化深床滤池跌水复氧控制措施的工程实践

反硝化深床滤池一般为露天池体,污水在跌落过程中,与大气充分接触,会使滤池中溶解氧增加,而溶解氧是导致反硝化深床滤池碳源利用率低的一个主因。选取大清河流域某污水厂为研究对象,开展反硝化深床滤池跌水复氧控制的工程研究。通过检测反硝化深床滤池溶解氧、水温、碳源利用效率等变化情况,发现反硝化深床滤池全年溶解氧均处于较高值,且夏季溶解氧、碳源投加量均低于冬季。通过对反硝化深床滤池顶部加盖密封进行复氧控制的工程改造实践,冬季运行结果表明,密封良好的加盖措施能有效控制滤池跌水复氧,滤池上层进水溶解氧由8.90 mg/L降至4.80 mg/L,且还具有一定的保温效果。污水厂在冬季运行时碳源投加量由191 mg/L减少至170 mg/L,平均每去除1 mg/L的总氮需投加碳源23.68 mg/L,碳源利用效率提高了约10%。

心电瀑布图结合散点图在诊断房性心律失常中的应用

目的探讨心电瀑布图结合散点图诊断房性心律失常的应用价值及优势。方法分析动态心电图中典型房性心律失常的心电瀑布图及散点图的变化特征,并总结其应用优势。结果不同类型房性心律失常的心电瀑布图和散点图具有不同的表现特征。(1)频发房性早搏:瀑布图特征为间歇性P峰带出现断裂,R、T峰带不变;散点图特征为早搏点位于快加速区。(2)房性自主节律:瀑布图特征为P峰带断裂,PR间期出现变化;散点图特征为该节律可融合于窦性节律集落中,与窦性节律难以区分。(3)间歇性短阵房性心动过速:瀑布图特征为P峰带断裂,出现两个或两个以上的R峰带;散点图特征为集落点可位于快加速区或45°线上,心率范围可与窦性心率区分,但发作时间无法确定。(4)持续性心房颤动:瀑布图特征为P峰带的消失和紊乱,R、T峰带不变;散点图特征为呈扇形图形。(5)心房扑动:瀑布图特征为P峰带断层,出现两个或两个以上的P峰带,并出现相应的PR间期;散点图特征为呈网格状图形。结论通过选择动态心电图上P-QRS-T波群变化明显的导联,并观察心电瀑布图上P、QRS、T峰带的变化特征,再结合心电散点图的变化,就可以准确、快速地判断房性心律失常的类型。