历史查询   



 为了更好的帮助您理解掌握查询词或其译词在地道英语中的实际用法，我们为您准备了出自英文原文的大量英语例句，供您参考。 
The law of the iterated logarithm for wavelet series


Precise rate in the law of iterated logarithm for ρmixing sequence


Furthermore, the precise asymptotics in the law of iterated logarithm of μ* is proved.


Precise rates in the law of the iterated logarithm for R/S statistics


The law of mechanical property indexes of the wire is presented.

 更多 


 In this article it is pointed out that the semiempirical van der Waals' equation of state for gases is particularly unsatisfactory in the neighborhood of the critical point, as indicated by the fact that the experimental values of the critical ratio (?) seldom agree with the theoretical constant value 8/3. It is also noted that this τ value may serve as a satisfactory measure (at least to a first approximation) of the deviation of the law of corresponding states when applied to gases at high densities.... In this article it is pointed out that the semiempirical van der Waals' equation of state for gases is particularly unsatisfactory in the neighborhood of the critical point, as indicated by the fact that the experimental values of the critical ratio (?) seldom agree with the theoretical constant value 8/3. It is also noted that this τ value may serve as a satisfactory measure (at least to a first approximation) of the deviation of the law of corresponding states when applied to gases at high densities. We have therefore proposed in this communication a rather straightforward modification of the van der Waals' equation which leads to an empirical threeconstant equation of state for gases involving this τ value as an adjustable parameter and thus requiring only critical data for the determination of the three constants. This equation is made to fit the pVT data at the critical point, but reduces itself to the simpler forms of the van der Waals' equation and the ideal gas equation for lower values of gas densities. Numerical calculations made for gases of widely different τ values show that this rather simple equation of state is fairly satisfactory even at high densities. The plausibility of using the τ value as an adjustable parameter both for the equation of state and for the law of corresponding states is also briefly discussed.  本文指出任何僅含兩個常數的氣態方程,在臨界點附近的缺點是特別顯著的。同時也指出,對應態定律應用到高密度氣體的偏差,可以相當滿意地用臨界係數(?)來衡量。因此我們建議將van der Waals方程,修改爲三常數的經驗方程,它的優點是這三個常數可以直接從氣體的臨界點數據計算出來;而且實例計算(包括極性很強和τ值很大的甲醇)說明它在相當大的温度和密度範圍內可以適用。將這個經驗式,寫成對比方程顯然含有臨界係數τ,就離開臨界點不太遠的氣體來說,這個函數關係可以相當满意地用本文方程總結出來。  The study of the distribution of hydrogen in steel ingots, despite its practical importance, has not received due attention from previous workers. Available experimental results are mainly fragmentary and nonsystematic, and therefore many disputable opinions exist. Desirous of investigating this problem in greater details, the authors employed several annealed ingots of high chromium steels which were considered to be particularly suitable because they evolved little gas at room temperature and consequently... The study of the distribution of hydrogen in steel ingots, despite its practical importance, has not received due attention from previous workers. Available experimental results are mainly fragmentary and nonsystematic, and therefore many disputable opinions exist. Desirous of investigating this problem in greater details, the authors employed several annealed ingots of high chromium steels which were considered to be particularly suitable because they evolved little gas at room temperature and consequently the inherent difficulty to avoid the loss of hydrogen during sampling was, to a very large extent, overcome. For this purpose also, suitable apparatus capable of determining relatively small amount of hydrogen was constructed. The results obtained show that the hydrogen distribution in the annealed ingots follows a significant and regular pattern, thus dismissing certain misgiving conclusions based on contradictory results given by previous workers. Although the average hydrogen content of the anealed ingots amounted to not more than half that of the liquid stael, yet in certain parts of their interior the local hydrogen content was found to be higher than that of the liquid steal. This affirms the existence of hydrogen segregation in steel ingots. Moreover, from maps of hydrogen contour lines drawn for the ingots it can be seen that the regions of the highest hydrogen content roughly coincide with the last solification. Indeed, the effect due to certain external irregularities encountered in the course of solification is detectable rather from the hydrogen maps than by the usual method of macroetching.In the longitudinal or the transverse direction of the annealed ingots, the general trend of hydrogen variation based on average hydrogen content is shown to be governed by the law of hydrogen diffusion. Further examinations reveal that the ingot structure and its internal porosity exert considerable influence upon the distribution. It is likely that hydrogen diffusion may be faster in columnar crystals than in equiaxed crystal regions. The presence of porosities in ingots seems to retard the removal of hydrogen. Such implications have not been sufficiently realized in the past.Based on the discussion of the experimental results, certain immunizing treatment suitable for preventing hairline cracks in certain types of steel is explained.  氢在鋼锭中的分佈是一个具有重要实际意义的问题,但在过去未得到研究工作者足够的重视.本文利用高铬型合金鋼在常温下不损失氢的特点,并建立了適宜的半微量定氢装置,对退火后的鋼锭中各个部位进行了定氢试验。结果证明,氢在鋼锭中的分佈是具有规律性的,指出了前人根据不全面的实验结果所提出的错误结论. 经过退火处理后的鋼锭,其平均含氢量虽然只及原来钢液含氢量的一半,伹在某些局部其含氢量反而高於钢液.这说明钢锭中确有氢的偏析现象存在.根据等氢曲线的分布情况来看,钢锭中氢偏析严重之处大致与最后凝固的部分相符.凝固过程中钢锭一面受到中注管散热的影响,也能从等氢曲线的分佈情况反映出来,而这种影响从低倍检验结果来看是没有能够觉察到的. 从氢含量变化的平均趋势来看,退火钢锭中的氢分佈不管是沿横方向抑是沿縱方向都服从於扩散规律,伹必须考虑到结晶构造和内部缺陷的影响.譬如,沿柱状晶轴方向的氢扩散似乎比等轴晶区域内的氢扩散速度大,而钢锭中心疏松对於去氢则起阻碍作用,过去对於这些方面的了解是不够的. 根据上述结果的分析讨论,本文还为某种防止钢中白点的热处理方法提供了理论上的解释.  This paper attempts to answer the following two questions: (1) Is it possible to derive the law of distribution of hydrological frequency theoretically(2) What type of distribution curve should be adopted as the model of hydrological frequency curve and how to determine their parameters? The results obtained may be summarized as follows: 1. Hydrological phenomena are time series with concealed periodic fluctuations. The results from statistical analysis based upon the current assumption that hydrological... This paper attempts to answer the following two questions: (1) Is it possible to derive the law of distribution of hydrological frequency theoretically(2) What type of distribution curve should be adopted as the model of hydrological frequency curve and how to determine their parameters? The results obtained may be summarized as follows: 1. Hydrological phenomena are time series with concealed periodic fluctuations. The results from statistical analysis based upon the current assumption that hydrological phenomena are independent stochastic variables should be accepted with due considerations. 2. In view of the regional nature of hydrological phenomena, the current parctice of analyzing samples taking from a single station only is, in effect, to narrow the sampling field arbitrarily from a larger area to a point, thus reducing the accuracy of the statistical results. Hence, the synthetic utilization of the data of all stations within the hydrologically homo geneous region is an important measure to increase the accuracy of statistical analysis. 3. The belief that the flood frequency obeys the binomial theorem or Poisson's theorem is but to mix up the priori with the empirical probability problem. The binomial theorem, being a powerful weapon to deal with the problems of priori probability, has not been adquately and properly utilized in the hydrologieal frequency analysis. 4. Analyses have been made of the nature of distribution of shydrologieal series on the basis of Kaptyen's derivation of the skew distribution, which indicate: (1) That the theoretical interpretation of the logprobability law of the hydrologic phenomena by V. T. Chow is not sound; (2) that hydrologic phenomena being results of very complicated meteorological and hydrological processes, it is impossible to derive theoretically the law of distribution for the hydrological series. 5. The view that the flood frequency obeys the Gumbel's distribution is theoretically not sound and also not verified by actual data. 6. According to the nature of the mathematical treatments applied, the method of description of the empirical probability can be classified into three systems: (1) The methods of the generalization of the characteristic factors of the distributions, such as Pearson's curves, Goodrich's curves, etc.; (2) The methods of the modification of a fundamental distribution by series and polynomials, such as GramCharlier curves. curves, etc.; (3) The methods of transformed functions, such as the logprobability law, curves, etc. It should be remarked that not only Pearson's and Goodrich's curves are frequency curves of empirical nature, but even the theoretical laws, such as the normal law and the logprobability law, will be aceepted as curves of empirical nature, when used as models for empirical probability problem. 7. Hydrological frequency analysis should not be mystified and made absolute. Instead of free selections, the models of hydrological frequency curve should be uniquely selected and specified. Statistical parameters should be determined not solely by the short period data of single station, but also by the synthetic utilization of the data of possible more stations. 8. It is recommended that one of the two types of distribution, i.e. the lognormal frequency curve with both sides limited and the Pearson's type Ⅲ curve, may be selected as unified models. The author suggests that the Kvalue corresponding to recurrence intervals of say 10~4, 10~5, or 10~6 years may be selected as the upper and lower limits for the lognormal curve. For Pearson's type III curves, C_s should be treated not as independent but as dependent variables of C_v. 9. The proper way to select and determine the model frequency curve is to see whether it fits well with the actual data of grouped stations (stations to be grouped by regions for rainfall data and by C_v for runoff data) and the reasonableness of the extrapolating part. 10. Suggestions on the method of determination of x and C_v: For point rainfall, isox map may be utilized, and the mean C_v for each hydrologicregion may be adopted in order to minimize the errors from single stations and to avoid the discrepancies in results obtained from the same region. With regard to flood frequency analysis, flood mark reconnaissance must be utilized to determine the magnitude and the recurrence interval of the unusual flood. The x and C_v values of the floods and runoffs of hydrologically similiar river basins may be compared. Besides, the reasonableness of the results of frequency calculations as well as of the statistical parameters adopted therein may be checked by comparing runoffs and pointrainfall values of the same frequency.  我国近期水文频率计算方法的研究工作在选择方法,经验频率公式,参数的误差和利用我国水文资料检验各种频率线型等方面有了一定的成果和实用的结论[1],但是下面两个问题还没有获得解决: (1)能否从机率理论证明水文频率属于何种分布律? (2)水文频率曲线应当采用什么线型?如何确定参数?本文试图解答以上两个问题。本文分析了水文系列的时序性质和区域性质,把机率问题按先验、极限和后验三种基本性质对水文频率问题进行了分析;利用开布屯推导偏态分布的方法分析了水文系列的分布性质,并从而批判了有关水文频率肯定属于对数正态律,耿贝尔极限律或二项式定理等等说法。认为属于后验机率性质的水文频率,不能从机率理论证明它属于何种分布律。最后提出联合利用各站水文资料来选择线型和确定参数的方法,并建议在两端有限对数正态和皮尔逊Ⅲ型两种线型中选择一种作为统一采用的线型,对两端有限曲线提出了简易可行的确定上下极限的方法,对皮尔逊Ⅲ型曲线认为应该把Cs作Cv的倚变参数。   << 更多相关文摘 
相关查询  



