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当机械设备发生故障时,厌氧螺纹锁固剂便可发挥作用。正如赛车的特滑层有助于确保车辆在赛道的抓地力,螺纹锁固剂有助于保证紧固件螺纹的夹持力。根据厌氧技术,这些金属胶粘剂可以实现机械辅助措施无法实现的功能:它们可完全填满连接螺纹之间的微小间隙。使用螺纹锁固剂固定的螺栓可以提供比机械装置更好的夹紧力。专用螺母或垫圈的价格是液体螺纹锁固剂的5倍以上。采用液体螺纹锁固剂可降低库存成本。在选择螺纹锁固复合物时,有一些关键因素需要考虑:抗剪强度、固化速度、间隙填充能力和工作环境。  相似文献   
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We introduce Noise Spectroscopy (NS) and show the results of an analysis of three data-sets demonstrating the feasibility of this technique. The NS effect is first shown to be present in a set of X-ray radiography images of low- and high-Z materials taken using the 6 MV Rapiscan Eagle P60HP portal cargo inspection system. Image-Based NS is, however, relatively insensitive. Using a data-set obtained using a fast plastic scintillator and photo-multiplier tube (PMT), we demonstrate that NS works very well when using fast detectors, fast electronics and waveform digitization. Another data-set was taken using Lutetium-Yttrium Ortho-Silicate (LYSO), which is suitable for use in X-ray cargo radiography. Although LYSO is slower than plastic scintillator, it was shown that NS also works very well using this material, paving the way for NS to be implemented using the primary imaging array of X-ray cargo inspection systems.  相似文献   
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Discharge Relation for Cutthroat Flume under Free-Flow Condition   总被引:2,自引:0,他引:2  
A cutthroat flume is commonly used as flow measuring device for open-channel flow due to ease of fabrication and installation. In most of the cases it is difficult to calibrate the flume in the field. Therefore, accurate relation between discharge and upstream head applicable for all sizes of cutthroat flume is needed. Seven different sizes of cutthroat flumes, having different length to throat width ratios, are fabricated and tested in the laboratory under free-flow condition. Selecting groups of different variables describing flow through a cutthroat flume number of dimensionless parameters are formed. Regression analysis of experimental data is carried out between all possible combinations of pairs of dimensionless parameters and the pair giving the best correlation is selected. Using the selected pair, relation between dimensionless parameters of discharge and head is developed. The relation is simple and convenient to use and, at the same time, more accurate compared to methods available in literature for prediction of discharge.  相似文献   
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The impurity atoms forming dipoles in the structure of KNbO3 are arranged regularly in the structure. The locations of the dipole sites were observed by etching technique, when dilute HNO3 was used as an etchant. The dipoles along with the domain structure with which they are associated are stable with respect to temperature, and retain the same sites at Curie temperature. Thus the regular cooperative ordering observed at room temperature also exists at the Curie transition. The importance of this ordering is discussed in terms of domain formation and the basic problem of ferroelectricity in crystals.  相似文献   
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Atmospheric InfraRed Sounder images are a type of ultraspectral images that are good candidates to compression as they include several thousand bands that account for well over 40 MB of data per single cube. As part of most prediction based compression schemes, there is a preprocessing stage in which a reversible band ordering process is included to maximize spectral band correlation. In this paper, we analyze, compare, and propose novel improvements to different band ordering and correlation estimation techniques in the context of ultraspectral image compression. In order to measure the performance of these methods, we also introduce a new metric based on comparing a given sequence of spectral bands to the corresponding optimal one. Finally, we apply the techniques presented in this paper to a real compression algorithm in order to obtain compression rates as a function of band ordering and correlation factors while determining the best scenario.  相似文献   
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OBJECTIVE: To analyze the effects of flutamide in patients with physical and/or mental disorders consulting for urinary symptoms secondary to benign prostatic hyperplasia (BPH). METHODS: 50 patients with BPH in whom surgical treatment was contraindicated due to their physical and/or mental condition were treated with flutamide 250 mg/day. Four patients presented with urinary retention and 46 patients had prostatic symptomatology. Patients were evaluated using the symptoms score (I-PSS) and quality of life (QL). Prostate volume was measured by transabdominal US; the maximum flow rate at spontaneous micturition and residual urine were determined. RESULTS: At 12 months, the I-PSS and QL scores decreased by a mean of 7 and 3 points, respectively. The US demonstrated that treatment had reduced prostatic volume by a mean of 10 gms. The maximum flow rate at spontaneous micturition increased 3 ml/sec and residual urine decreased by 15 ml. CONCLUSION: Flutamide is another alternative to surgery in specific patients with BPH.  相似文献   
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