基于BP算法的金刚石钻头设计专家中的配方设计子系统     

张绍和  赵显富  刘琛  鲁凡  张泰山 《地质与勘探》1999,35(3):54-56,65

介绍金刚石钻头设计专家系统中的配方设计子系统,包括多层感知机数学模型和ＢＰ算法,专家子系统的设计,钻头配方参数样本的网络训练,给出了钻头配方设计的典型数据。实践表明ＢＰＦＥＳ用于钻头配方设计是可行的,具有人工智能的特性。  相似文献   

淘汰一字形钎头          下载免费PDF全文

张国榉  饶建华 《探矿工程》1999,(5):38-40

因一字形钎头破岩效率低和几何形状结构缺陷等问题,瑞典从７０年代中期就用锥体连接的十字和球齿钎头取代了一字形犴头。现在,我们建议用更具优势的复合片齿钎头逐步更新一字形钎头,新系列钎头寿命为一字,球齿钎头寿命的２－４倍,而价格仅比同直径一字,球齿钎头高１／５－１／３。  相似文献   

冲击回转挤压成孔方法及凸轮型挤压钻头   总被引：1，自引：0，他引：1       下载免费PDF全文

郑治川  邓洪超  卢文阁 《探矿工程》1999,(4):8-10

在冲击回转挤压成孔的钻进中通常采用圆锥型的挤压钻头,这种钻头在松软地层中的钻进效率很高,但在高围压下的中、硬塑性地导中的钻进效率明显降低。针对这一问题,分析了地层因素对钻进效率的影响及其原因,针对圆锥型挤压钻头存在的问题,设计了凸轮型挤压钻头。并指出了冲击回转挤压成孔钻进方法的适用范围。  相似文献   

复杂地层钻进中贯通式潜孔锤的应用及反循环钻头的改进   总被引：7，自引：0，他引：7  

王茂森殷琨  陈宝义贾林 《煤田地质与勘探》2005,33(5):79-80

针对贯通式潜孔锤在复杂地层钻进中遇到的问题,对反循环钻头进行了改进:在钻头上部增加喷射孔,使气流只有一少部分进入孔底,大部分经喷射孔直接进入内管,排至地面。生产试验证明,改进后的反循环钻头更有利于形成反循环,使用效果良好。   相似文献   

GPS BINARY数据向RINEX数据转换方法     

李为乔  程鹏飞  蔡艳辉  徐彦田  徐寿志 《全球定位系统》2010,35(4):21-25

将GPS接收机接收到的二进制原始数据流转换成十进制数据,可以用于实时导航定位或者进行标准RINEX格式用于后处理及验证。针对Hemisphere GPS接收机二进制格式数据,进行了程序设计,定义了位段结构体,并结合位运算程序实现二进制数据到十进制数据或标准的RINEX文件数据实时转换,并给出了程序实现中设计的类与相应的结构体。最后结合实例分析验证了该方法的可靠性。  相似文献   

温度或盐度对水下量子密钥分配影响的研究     

沈园  赵士成  于永河  马晓平  肖芽  李文东  顾永建 《中国海洋大学学报(自然科学版)》2021,51(5)

水下量子密钥分配对保障水下通信安全具有十分重要的意义。本文研究不同温度或盐度的海水对光传输以及水下量子密钥分配的影响。本文在有限的范围内改变水槽中水的温度或盐度,在温盐均匀和有温盐差的海水信道中对出射光进行偏振测试,并进行了基于偏振编码的BB84协议水下量子密钥分配实验研究。研究表明:偏振光经过温盐均匀或有温盐差的模拟海水后其偏振态几乎不发生变化;在温盐均匀的海水中,温度或盐度的变化几乎不改变误码率,但在温盐不均匀的海水中,误码率随温盐差的增大呈增加趋势。  相似文献   

煤田泡沫绳钻应用与问题探讨   总被引：1，自引：0，他引：1  

张晓宏 《煤田地质与勘探》1994,22(2):55-60

采用国产设备及自行设计配套的灌排系统首次在国内进行了金刚石泡沫绳钻试验,达到了217.74m的最大应用孔深;分析了试验中获得的钻进时效、纯钻进时间率两项主要效果指标;探讨了影响压降的几个关系问题;基本明确了煤田泡沫金刚石绳钻风量、气压等关键参数的变化规律和泡沫稳定运行的重要性。   相似文献   

新型针状硬质合金-金刚石复合型钻头     

杨展  段隆臣  兰桥昌 《地质科技情报》2006,25(4):101-104

介绍了针状硬质合金-金刚石复合型钻头的设计与制造工艺以及在孕镶针状硬质合金钻头基础上复合金刚石的研究方法。对针状硬质合金规格、性能以及排列方式提出了有实用价值的设计,并对金刚石的品级、浓度、粒度及钻头的烧结工艺进行了较深入的试验研究。生产性试验表明,该类型钻头对于钻进硬而破碎地层、软硬夹层以及卵砾石地层均具有很好的使用效果。  相似文献   

Trends in annual discharge from the Yangtze River to the sea (1865–2004) / Tendances et épisodes extrêmes dans les débits annuels du Fleuve Yangtze débouchant dans la mer (1865–2004)     

《水文科学杂志》2013,58(5)

Abstract

Uninterrupted records of annual discharge from the Yangtze River to the sea (at Datong Hydrographical Station) began in the 1950s. This series shows no significant trend. However, at Hankou, a station upstream from Datong, annual discharges have been observed since 1865 almost without gaps. The annual discharges at Datong and Hankou were found to be closely correlated. Based on the regression equation, the missing annual discharges at Datong were estimated and a time series from 1865 to 2004 was established. Although the annual discharge has varied greatly, it shows a significant decreasing trend. The trendline revealed an 8.2% decrease from 1865 to 2004. The decrease in discharge was attributed to increases in water consumption and reservoir construction, while the interannual variations were related to climate variability. The decreasing trend in discharge is expected to continue in the coming decades due to human activities. This decreasing trend should be taken into account in the decision making on the South-to-North-Water Diversion projects.  相似文献   

Precipitation,temperature and runoff analysis from 1950 to 2002 in the Yangtze basin,China / Analyse des précipitations,températures et débits de 1950 à 2002 dans le bassin du Yangtze,en Chine     

《水文科学杂志》2013,58(1)

Abstract

Abstract Monthly precipitation and temperature trends of 51 stations in the Yangtze basin from 1950–2002 were analysed and interpolated. The Mann-Kendall trend test was applied to examine the monthly precipitation and temperature data. Significant positive and negative trends at the 90, 95 and 99% significance levels were detected. The monthly mean temperature, precipitation, summer precipitation and monthly mean runoff at Yichang, Hankou and Datong stations were analysed. The results indicate that spatial distribution of precipitation and temperature trends is different. The middle and lower Yangtze basin is dominated by upward precipitation trend but by somewhat downward temperature trend; while downward precipitation trend and upward temperature trend occur in the upper Yangtze basin. This is because increasing precipitation leads to increasing cloud coverage and, hence, results in decreasing ground surface temperature. Average monthly precipitation and temperature analysis for the upper, middle and lower Yangtze basin, respectively, further corroborate this viewpoint. Analysis of precipitation trend for these three regions and of runoff trends for the Yichang, Hankou and Datong stations indicated that runoff trends respond well to the precipitation trends. Historical flood trend analysis also shows that floods in the middle and lower Yangtze basin are in upward trend. The above findings indicate that the middle and lower Yangtze basin is likely to face more serious flood disasters. The research results help in further understanding the influence of climatic changes on floods in the Yangtze basin, providing scientific background for the flood control activities in large catchments in Asia.  相似文献