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71.
在总结了型钢混凝土(SRC)柱承载力计算一般方法的基础上,针对T形型钢混凝土柱,结合中国现行规范,分析了此种柱的受力特点和破坏模式,提出T形型钢混凝土柱正截面极限承载力的计算方法,并采用该方法对一T形型钢混凝土柱的承载力进行验算. 结果表明与试验数据吻合较好,说明本文方法具有较好的精确度和适用性. 相似文献
72.
In this paper, a solution for the equilibrium configuration of an elastic beam subject to three-point bending is given in terms of Jacobi elliptical functions. General equations are derived, and the domain of the solution is established. Several examples that illustrate a use of the solution are discussed. The obtained numerical results are compared with the results of other authors. An approximation formula by which the beam load is given as a polynomial function of beam deflection is also derived. The range of applicability of the approximation is illustrated by numerical examples. 相似文献
73.
Wim van Aarle Wolfgang Ludwig Andrew King Dayakar Penumadu 《Journal of Applied Crystallography》2015,48(2):334-343
Recently, the concept of X‐ray diffraction contrast tomography (DCT) has been extended to the case of more widely available laboratory source CT systems. Using well known concepts from geometrical ray optics, an exact formulation is derived for the forward and backward projection geometry encountered under polychromatic cone beam illumination, and it is shown how this projection model can be efficiently implemented in practice. The new projection model is subsequently used for iterative tomographic reconstruction of the three‐dimensional shape of a grain from a set of experimentally observed cone beam projections and shows a clear improvement compared to the simplified projection model used previously. 相似文献
74.
Nan Zheng Zhiyong Yi Zhenzhen Li Ran Chen Yuqing Lai Yongfeng Men 《Journal of Applied Crystallography》2015,48(2):608-612
A grazing‐incidence sample stage was designed for realizing grazing‐incidence scattering measurements, especially in the ultra‐small‐angle regime, in a modified Xenocs Xeuss system in the laboratory. The designed sample stage, which is composed of four separate motorized positioning stages, allows the sample to be moved along four different directions to locate it in the proper position for scattering measurement. In an effort to realize grazing‐incidence ultra‐small‐angle scattering (GIUSAXS) measurements, both the separation of the collimation slit systems and the sample‐to‐detector distance have been lengthened. At a separation of the collimation slit systems of 2400 mm and a sample‐to‐detector distance of 6558 mm, the effective smallest scattering vector magnitude qmin reaches 0.01 nm−1. A colloidal crystalline thin film obtained from drying a polystyrene latex dispersion on silicon substrate was measured in the setup in GIUSAXS mode at different beam sizes. The resultant GIUSAXS patterns at smaller beam sizes reveal fine crystalline structures in the film. 相似文献
75.
Romain Moury Klaus Hauschild Wolfgang Kersten Jan Ternieden Michael Felderhoff Claudia Weidenthaler 《Journal of Applied Crystallography》2015,48(1):79-84
An in situ diffraction cell is presented which has been designed and constructed for in‐house powder diffraction experiments under high gas pressures up to 30 MPa. For a proof of principle, the in situ cell has been tested for several hydrogenation experiments under elevated pressures and temperatures. LaNi5 was chosen as an example for hydrogenation, applying simultaneously 5.5 MPa H2 pressure at a temperature of 423 K. For testing the high‐pressure–temperature suitability of the in situ cell, pressure–temperature experiments up to 14 MPa at 373 K were performed, studying the rehydrogenation of NaH and Al to NaAlH4. The experimental setup enables recording of in situ X‐ray diffraction data on laboratory instruments with short data acquisition times at elevated hydrogen pressures and temperatures. 相似文献
76.
77.
Jan W. H. Swanepoel Francois C. Van Graan 《Annals of the Institute of Statistical Mathematics》2002,54(3):531-542
New goodness-of-fit tests, based on bootstrap estimated expectations of probability integral transformed order statistics, are derived for the location-scale model. The resulting test statistics are location and scale invariant, and are sensitive to discrepancies at the tails of the hypothesized distribution. The limiting null distributions of the test statistics are derived in terms of functionals of a certain Gaussian process, and the tests are shown to be consistent against a broad family of alternatives. Critical points for all sample sizes are provided for tests of normality. A simulation study shows that the proposed tests are more powerful than established tests such as Shapiro-Wilk, Cramér-von Mises and Anderson-Darling, for a wide range of alternative distributions. 相似文献
78.
V. Kanišauskas 《Lithuanian Mathematical Journal》2000,40(3):241-247
In this paper, we consider the problem of asymptotically minimax testing ofr≥2 simple hypotheses when a general stochastic process is observed. We establish general conditions for the exponential decrease
of maximal probability errors of minimax tests as the number of observations increases. At the present time, similar results
for testing several multinomial schemes were obtained by Salihov [8]. Similar results for testing two simple hypotheses were
obtained in [5]. In the proofs of the main results, we use the theory of large deviations ([3], [2]). In Sec. 1, the main
result is proved. In Secs. 2–4, we analyze the i.i.d. case, nonhomogeneous Poisson processes, and renewal processes as examples.
Published in Lietuvos Matematikos Rinkinys, Vol. 40, No. 3, pp. 313–320, July–September, 2000. 相似文献
79.
Summary Recently much attention has been directed to the validation of analytical methods. The level of validation will depend on the method application. If a method is developed for general use, for instance by different analysts, instruments or laboratories, then the effect of these changes need evaluation. This is normally referred to as ruggedness testing, where the limitations of the method to changes in the specified conditions are examined.This paper examines the use of Plackett-Burman fractional factorial experiment designs for ruggedness testing in high performance liquid chromatography (HPLC). The ability of these designs to identify confounding effects is applied to the stability indicating analysis of Salbutamol and its major degradation product, AH4045. The results show that confounding effects, proving extremely pertinent to HPLC, can be identified.The assay proved rugged to most tested changes although not to the use of column packing material from different manufacturers. 相似文献
80.