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421.
422.
越冬花椰菜气候适应性研究及灾害防御技术 总被引:1,自引:0,他引:1
2002~2004年试验研究结果表明,越冬花椰菜幼苗期适宜温度为15~25℃,最低温度5~7℃,最高温度25~30℃。莲座期适宜温度为4~20℃,最低-1~-3℃,最高21~22℃。花球形成期适宜温度一般为14~21℃,最低8~10℃,最高21~30℃。花椰菜生育期耗水量在767.2~933.5 mm之间,水分利用效率最高,超过950 mm或低于510 mm水分利用效率均显著降低。花椰菜生育期间低温冷害和高温伤害是造成减产和品质降低的主要气象灾害。 相似文献
423.
Masaho Yoshida Masaru Tonoo Masakatsu Miyajima Masaru Kitaura 《东北亚地学研究》2006,9(2):150-155
The 2004 Niigata-ken Chuetsu earthquake in Japan caused serious damage to sewage facilities such as uplift of manholes and settlement of pavement above backfill soil for pipes.This paper deals with shake table tests in a 1 g gravity field on application of recycled materials for ground improvement to mitigation of liquefaction-induced flotation of manhole during earthquakes.The recycled materials used in tests were tire chips made of waste tires and crushed gravels made of waste reinforced concrete,and they were packed in sandbags.From the test results,it was confirmed that the recycled materials packed in sandbags could be treated as one of the countermeasures to restrain the flotation of manholes and settlement of ground surrounded by sandbags. 相似文献
424.
The aim of this work is to build an EUV-UV spectral catalogue of a prominence. Here we focus on the preparatory work for the final result and we give an example of the results obtained. As a first step, we present the information needed for a full understanding of the results that will form the final entire catalogue. The data are composed of a full SUMER spectrum in the range 800–1250 Å of a prominence observed on 8 October 1999. A quiet-Sun area was also observed in the same spectral range in order to have a reference spectrum. Beside the standard corrections, we give details of the estimated stray light and the wavelength calibration of both datasets. We also present a short list of lines as an example of the results from the line-fitting procedure we applied to the data. For each line we give the measured position, the total intensity and the FWHM in the quiet Sun and at two different spatial positions in the prominence. With a final atlas of the prominence it will be possible to investigate several properties of the feature such as mass motion, differential emission measure, density, and elemental composition. 相似文献
425.
We report results of our optical photometric observations of ten gamma-ray loud blazers, namely: 0219+428 (3C66A), PKS 0420-014 (OA 129), S5 0716+714, 0754+100 (OI 090.4), 0827+243 (OJ248), 1652+398 (Mrk 501), 2200+420 (BL Lacertae), 2230+114 (CTA 102), 2251+158 (3C 454.3) and 2344+514. The observations were carried out in September-October, 2000 using the 70 cm optical telescope at Abstumani Observatory, Georgia. We found intra-day variations in 0420-014, S5 0716+714, BL Lacertae and CTA 102. A variation of 0.3 magnitude over a time scale of about 3 hours was observed in the R passband in BL Lacertae on JD 2451827. We did not detect any variation in 3C 66A, Mrk 501, or 3C 454.3 during our observations. Nor did we detect any clear evidence of variation in 1ES 2344+514 during our two weeks' observing run of the TeV gamma-ray source. 相似文献
426.
在声光频谱仪的中频输入端输入一个梳状讯号,分析输出的频谱,可以测定声光频谱仪的谱分辨率、频谱漂移等重要工作参数.这是进行谱线天文观测前必做的准备工作.我们对紫金山天文台用于13mm星际水脉泽观测的高频率分辨率的AOS-Ⅰ进行了仔细的频谱工作性能测定,结果发现它有良好的性能:平均通道间隔12.10±0.02kHz,平均谱分辨率221±1.8kHz,谱分辨率随时间变化1.0kHz/天,通带内谱分辨率起伏上1.0kHz,总工作带宽12.39MHz. 相似文献
427.
. ]Qi . , r=r. . , . H>2G, — , . , . . .
The exact solutions for the equilibrium of rotating gaseous disk with poloidal magnetic field are obtained. The stability of the disk with respect to uniform expansion and contraction is investigated by means of the variational principle. It is shown that if the equilibrium is determined by gravitational and magnetic forces only, the disk is in neutral equilibrium with respect to perturbations of the form r=r. The instability to short-waves perturbations is studied by the quasi-classical method. The analysis shows that if the magnetic field isH>2G, where is the surface density, then these perturbations are stabilized. The configurations of the electrical field induced by the rotation of magnetized disk are found. In conclusion, the questions of the evolution of the disk are discussed in connection with the quasar model when pulsar-like radiation is taken into account.相似文献
428.
The design of an experiment for the determination of binding parameters in the association between aligand and a macromolecule with two groups of non-interacting binding sites is proposed.In theGauss-Newton non-linear least squares treatment the standard deviation of each parameter is given asthe product of two terms:one depending on the experimental error and the other,the diagonal elementof the dispersion matrix,depending only on the independent variables of the system.In order to reachan optimal experimental design,these diagonal elements of the information matrix have to be minimized.In our approach this is achieved by searching those values of the independent variable which maximizethe determinant of the information matrix.Furthermore,the limits of validity of the model are deducedfrom an analysis of the diagonal elements of the information matrix obtained under optimal conditions. 相似文献
429.
北极海冰数值模拟研究述评 总被引:7,自引:0,他引:7
根据国内外近年发表的主要文献,详细介绍北极海冰数值模拟工作的最新进展。综合评述各种主要动力学模式的特点和不足,指出与数值模式有关的主要物理问题,重点介绍海冰模式所特有的问题以及海冰数值模拟工作的发展方向。对以往的数值工作和海冰数值模拟的主要问题进行了总结,并在理论和实践方面进行了深入探讨,有助于我国相关工作的开展。 相似文献
430.