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991.
该文采用天气动力学分析方法,重点探讨北部湾低压向北部湾热带风暴发展的时空手物理机制,文章着重讨论了这类过程的高低层形势特征和空间结构,并通过诊断场计算分析揭示了这类过程的空间动力场插手玫各层的水汽分布特征,归纳出了北部湾低压向热带风暴发展的短期预报着眼点。 相似文献
992.
993.
微波诱导等离子体原子发射光谱法测定汞的研究 总被引:1,自引:0,他引:1
研究了以常压低功率氩微波诱导等离子体为激发源的原子发射光谱测定Hg的方法。采用超声雾化、水冷凝、浓H_2SO_4吸收去溶的进样方法,考察了微波前向功率、载气流速、KCl和NH_4Cl浓度、酸度等因素对Hg发射强度的影响。方法已用于试样分析。 相似文献
994.
Based on an asymmetric multistorey frame building model, this paper investigates the influence of a building's higher vibration modes on its inelastic torsional response and evaluates the adequacy of the provisions of current seismic building codes and the modal analysis procedure in accounting for increased ductility demand in frames situated at or near the stiff edge of such buildings. It is concluded that the influence of higher vibration modes on the response of the upper-storey columns of stiff-edge frames increases significantly with the building's fundamental uncoupled lateral period and the magnitude of the stiffness eccentricity. The application of the equivalent static torsional provisions of certain building codes may lead to non-conservative estimates of the peak ductility demand, particularly for structures with large stiffness eccentricity. In these cases, the critical elements are vulnerable to excessive additional ductility demand and, hence, may be subject to significantly more severe structural damage than in corresponding symmetric buildings. It is found that regularly asymmetric buildings excited well into the inelastic range may not be conservatively designed using linear elastic modal analysis theory. Particular caution is required when applying this method to the design of stiff-edge frame elements in highly asymmetric structures. 相似文献
995.
In this paper, the main meteorological and meteorologically induced marine disasters in Shanghai are climatologically investigated on the basis of historical qualitative documentary records and quantitative data. Statistics show that disasters may be classified into six different kinds, of which three are fundamental, i.e. floods, winds, and storm surges. Emphasis is placed on the detailed analysis and discussion of floods, tropical cyclones, and Mei-yu which affect Shanghai and cause destructive calamities.Firstly, the classification of floods, their frequencies, and geographical distribution characteristics are described and the regulation of the climatic variation of floods is revealed. Secondly, the frequency, source regions, seasonal variations, tracks, and translatory speeds of tropical cyclones affecting Shanghai, and their induced strong winds, storm rainfalls, and storm surges are systematically studied. Many meaningful conclusions have been reached for providing the climatological background of Shanghai.The climatic change and its regulation of these main disasters in Shanghai have been basically clarified throughout this study. 相似文献
996.
997.
微波诱导等离子体原子发射光谱法测定铍铬钼钒锆锗的研究 总被引:1,自引:0,他引:1
研究了用微波诱导等离子体原子发射光谱法(MIP-AES)测定Be、Cr、Mo、V、Zr和Ge。确定了最佳实验条件,其检出限分别为:0.038,0.030,0.015,0.030,0.024和0.11μg/ml。对实际样品进行了测定,结果令人满意。 相似文献
998.
CHARACTERISTICS OF ATMOSPHERIC HEATING AND ATMOSPHERIC CIRCULATION DURING ACTIVE PERIOD OF 500 hPa HIGH OVER THE TIBETAN PLATEAU IN SUMMER
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段廷扬 《Acta Meteorologica Sinica》1994,(1)
In correspondence with the establishment of the“upper high and lower high”pressure pattern due to the activitiesof 500 hPa high over the Tibetan Plateau in summer,a series of changes of the East Asia atmospheric circulation willtake place.In this paper,the distributions of divergence and vertical velocity of 500 hPa high,the evolutions of atmos-pheric heat source,the variations of vorticity and zonal wind at 100 hPa level and vertical meridional cell over theTibetan Plateau etc.are statistically analyzed.Thus,we can see that the ascending motion and the convective heatingover the Tibetan Plateau,the South Asia high and the westerly jet on the north of the Plateau at 100 hPa level are weak-ened.The northern branch and the southern branch of the easterly jet on the south of the Plateau merge into a singlewhole and situate on the south of the former northern branch.In the meantime,thermodynamic land-sea discrepancy inSouth Asia and the convective heating over the Bay of Bengal is enhanced.It will play an important role in the mainte-nance of the easterly jet and the South Asia monsoon. 相似文献
999.
山西地区分区近震走时表的编制与检验 总被引:1,自引:0,他引:1
主要以山西太原、大同、临汾3个遥测台网的记录,结合山西省内及邻省部分台站的地震观测资料,用勘探、爆破与测震方法得出山西地区地壳模型结构。用观测走时与理论走时对比,划分出6个区域,计算出"山西地区近震走时表"及"山西南部地区近震走时表"。检验结果表明,发震时刻、震中位置及深度等各项参数较J-B走时表均有极大的提高。经试用确认其适用于山西地区。 相似文献
1000.
1999年9月21日台湾省南投县发生了7.6级的强烈地震,当时正好我当班,在地动房摇的情况下,加上这次地震的特殊性,将S波分的较向后,使地震“三要素”中的震中位置有误差,现将这次主震的分析过程做一总结。 相似文献