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31.
本文在综述了目前稳定流涌水量经验方程建立方法的基础上,根据最小二乘法原理,提出了一种新的方法—最小残差法,并给出了计算实例。计算表明,最小残差法是建立稳定法涌水量经验方程的一种较好方法,计算过程在微机上易于实现。  相似文献   
32.
河北汉诺坝玄武岩中长英质麻粒岩、镁铁质麻粒岩和辉石岩捕虏体的主量元素和微量元素特征,反映了下地壳及壳幔过渡带组成具有高度化学不均一性。不相容元素原始地幔标准化曲线特征的差异表明捕虏体成因复杂。MgO与不相容元素无或仅有很弱的相关性,与相容元素的相关性则相对较明显。这些特征反映了下地壳及壳幔过渡带存在较强和多元的混合作用。捕虏体的加权平均值比基于麻粒岩地体资料估算的下地壳平均组成偏基性,揭示了二者可能的成因差异。  相似文献   
33.
Microbes are believed to play important roles in ecosystem function in many environments. The hot springs of Xiamen Island are close to the Xiamen Sea, and may have some characteristics different from those of inland hot springs. Microbes living in the hot springs of Xiamen may have new characteristics. However, little is known about microbial communities of hot springs close to the Xiamen Sea. A culturedependent survey of microbial population in the Xiamen hot springs was performed by using an approach combining total cellular protein profile identification and 16S rRNA gene sequencing. A total of 328 isolates of bacteria were obtained from liquid and sediment samples from the Xiamen hot springs, including neutrophilic thermophilic bacteria and moderately thermophilic acidophiles. Neutrophilic thermophilic bacteria, which grow at a temperature range of 55—90℃ including Rhodothermus marinus (Strain 1), Thermus thermophilus (Strain 2), Thermus thiopara (Strain 3), Geobacillus stearothermophilus (Strain 4), Geobacillus thermoleovorans (Strain 5), and Pseudomonas pseudoalcaligenes (Strain 6), were recovered by 2216E plates. Moderately thermophilic acidophiles, which can grow at temperatures above 50℃ and a pH range of 1.8—3.5 such as Alicyclobacillus acidoterrestris (Strain 8), Sulfobacillus acidophilus (Strain 9), and Sulfobacillus thermosulfidooxidans (Strain 10), were isolated on selective solid medium containing sulfur and Fe2+. Among these strains, Rhodothermus marinus, Thermus thermophilus and Geobacillus stearothermophilus are not only thermophiles, but also halophiles. One bacterium strain (Strain 6) shared 99% nucleotide sequence homology with Pseudomonas pseudoalcaligenes on the 16S rRNA gene sequence, but was quite different from Pseudomonas pseudoalcaligenes in biological characteristics, suggesting that it may represent a novel thermophilic species. Results indicated that various species of neutrophilic thermophiles and moderately thermophilic acidophiles were widely distributed in the Xiamen hot springs and that Rhodothermus marinus and Thermus thermophilus dominated the cultivable microbial community.  相似文献   
34.
对水中泥沙、气泡群、鱼群等随即分布散射体群的声学回波统计特性进行了研究,建立了一种基于回波能量统计特征的水下散射体数量密度评估模型。对该模型进行了介绍与推导,并通过仿真试验证明了其对水下散射体数量密度评估的有效性。  相似文献   
35.
山西寿阳—阳泉地区石炭—二叠系沉积环境及其沉积特征   总被引:1,自引:0,他引:1  
本区石炭—二叠系是在海湾背景下发育的一套由滨海平原—三角洲平原—冲积平原沉积组成的海退层系。主要沉积环境是三角洲平原,其上部为冲积平原包括网状河和辫状河;下部为海湾(或分支间湾)、潮下碳酸盐岩、潮间介壳滩、碎屑岩潮坪及滨海沼泽湿地等。三角洲为河控浅水三角洲。上述沉积环境,随海水退却在时空上具明显的规律性变化。  相似文献   
36.
本文分析了30例肺癌的 MRI 及手术病理分期的结果。结果表明:MRI 能够比较准确地显示肿块的大小、范围、部位及叶以上支气管的受累情况;容易显示胸壁、纵隔、隔肌及远处转移,对胸壁受侵犯诊断准确率为86.7%;无需使用造影剂能直接显示肺门及纵隔区大血管的受累与否、诊断准确率为83.3%;对肺门及纵隔淋巴结转移诊断准确率为90%,敏感性为91.3%,特异性为85.7%;与手术病理分期结果比较,MRI 对肺癌分期准确率为80%。故认为 MRI 是对肺癌分期癌一种准确的无创性新方法。  相似文献   
37.
Geoeffective Analysis of CMEs Under Current Sheet Magnetic Coordinates   总被引:1,自引:0,他引:1  
Using 100 CME–ICME events during 1997.01–2002.11, based on the eruptive source locations of CMEs and solar magnetic field observations at the photosphere, a current sheet magnetic coordinate (CMC) system is established in order to statistically study the characteristics of the CME–ICME events and the corresponding geomagnetic storm intensity. The transit times of CMEs from the Sun to the Earth are also investigated, by taking into account of the angle between the CME eruption normal (defined as the vector from the Sun center to the CME eruption source) and the Sun-Earth line. Our preliminary conclusions are: 1. The distribution of the CME sources in our CMC system is obviously different from that in the ordinary heliographic coordinate system. The sources of CMEs are mainly centralized near the heliospheric current sheet (HCS), and the number of events decreases with the increment of the angular distance from the CME source to the HCS on the solar surface; 2. A large portion of the total events belong to the same–side events (referring to the CME source located on the same side of the HCS as the Earth), while only a small portion belong to the opposite–side events (the CME source located on the opposite side of the HCS as the Earth). 3. The intense geomagnetic storms are usually induced by the same–side events, while the opposite side events are commonly associated with relatively weak geomagnetic storms; 4. The angle between the CME normal and the Sun–Earth line is used to estimate the transit time of the CME in order to reflect the influence of propagation characteristic of the CME along the Sun–Earth direction. With our new prediction method in context of the CMC coordinate, the averaged absolute error for these 100 events is 10.33 hours and the resulting relative error is not larger than 30% for 91% of all the events.  相似文献   
38.
梭鱼标准代谢、内源氮排泄与体重和温度的关系   总被引:5,自引:0,他引:5  
在 13.5 ,18,2 1.5 ,2 4和 2 7℃ 5个温度条件下测定了梭鱼 (体重范围 1.88~ 14.0 2 g)的标准代谢率和内源氮排泄率。梭鱼标准代谢率随体重的增加而增加 ,二者的关系为幂函数关系 ;随温度的升高而增加 ,二者的关系为指数关系 ;标准代谢率与体重和温度的关系可用如下方程表示 :RS=0 .12 4 6 W0 .9954 e0 .0 84 1T(r2 =0 .92 2 0 )。梭鱼的氨氮、尿素、总氮及能量的排泄率随体重和温度的增加而增加 ,与体重为幂函数关系 ,与温度的关系为多项式形式。梭鱼氨氮和尿素日排泄率的变幅分别为 0 .15~ 0 .88mg N/d和 0 .0 3~ 0 .2 9mg N/d。不同温度下 ,尿素排泄量占总氮比例在 9.9%~2 2 .4 9%之间 ,随温度升高该值有逐渐增大的趋势。  相似文献   
39.
The numerical fracture analysis of non‐homogeneous rock or concrete dowels subjected to shear and compression is described in detail. The method of analysis allows the consideration of scale and rate effects due to material non‐homogeneity and fracture. The proposed approach is verified by comparing numerical predictions with experimental results reported in the literature for a series of small rock samples, since experimental evidence for large bodies is not yet available (2007). Results generated by Monte Carlo simulation using the so‐called discrete element method to model the dowels suggest that a simple three parameters law can be used to predict the relationship between tangential stress at the base and lateral distortion. It is observed that the larger the size of the cubes, the smaller both the peak tangential stress and the rupture distortion. Size effects are also evaluated in samples with vertical restraint. The influence of loading rate is likewise numerically assessed for two sample sizes. The effect is compatible with experimental evidence available for concrete using small samples. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
40.
提出了一种基于可信度操作的从灰度变化信息获取表面形状的方法,并结合在频率域的强制可积约束,把对表面梯度空间(p,q)的处理经过高斯球变换到(f,g)空间处理,不仅较好地保证了算法的收敛性和可靠性,而且有利于边界条件的确定。  相似文献   
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