GRB Energies and Eγ - Epeak Correlation with the Jet Expanding Laterally at the Sound Speed

A Gamma-ray burst (GRB) is generally believed to be a jet with a small opening angle, this opening angle is usually derived with the afterglow light curve break time using an analytical method. Here we show that the method is not accurate. Using the set of equations of hydrodynamic evolution with the sideways expansion at the local sound speed derived by previous authors and the observed light curve break times, we numerically derive the initial opening angles. Then the collimation-corrected energies (Eγ) for a sample of GRBs are calculated. They are found to show a wide spread, suggesting that the previously declared clustering by some authors may not exist. Also, the Epeak -Eγ relation, claimed by some other authors (Epeak is the spectral peak energy), is found still to hold, with a slightly stronger correlation.     

The Multi-Wavelength Quasar Survey Ⅲ. Quasars in Field 836

This is the third paper in a series connected with our Multiwavelength Quasar Survey. The survey is aimed to provide a quasar sample more complete than any previous survey by using a combined selection technique to reduce selection effects. We present the observational results for the X-ray candidates in field f836. We found 15 X-ray AGNs in this field of which eight are new discoveries. The X-ray data and optical spectra of these AGNs are given. We give the X-ray candidate selection criteria, which proved to be highly efficient in isolating X-ray AGNs.     

青海滩间山金矿床找矿矿物学研究

本文重点讨论了滩间山金矿床主要矿石矿物的标型特征及其地质意义,可用于矿床类比及该类型金矿床的找矿评价和预测。     

日珥线光谱的降维法分析

本文提出了多搜索变量的目标函数直接优化法。该方法不涉及目标函数的导数计算,通用性强;同时该方法可控制搜索变量在值域内取值,这在一定程度上保证了解的可靠性。用此方法,本文分析了1984年2月18日太阳边缘环珥的一些Hα谱线,结果表明,本文方法具有收敛半径大,精度高的特点。     

用惩罚函数法拟合耀斑后环光谱

在光谱拟合分析过程中,由于谱线的不对称,目标函数呈现出较强的非线性;拟合参数增多,需要对拟合参数的定义域进行约束。本文利用完全线性化方法处理非线性目标函数,用惩罚函数法对拟合参数约束。并用这种方法,拟合计算了1984年2月18日环珥的一些不对称谱线。     

Statistic characteristics of thermal structure in the southern Yellow Sea in summer

Based on the temperature data along 34°N, 35°N and 36°N sections in August from 1977 to 2003, the structure and formation of the Southern Yellow Sea Cold Water Mass (SYSCWM) and its responses to El Nino events are analyzed. Results show that: (1) There exist double cold cores under the main thermocline along the 35°N and 36°N sections. Also, double warm cores exist above the main thermocline along the 36°N section. (2) Thermocline dome by upwelling separates the upper warm water into two parts, the eastern and western warm waters. Additionally, the circulation structure caused by upwelling along the cold front and northeastward current along the coast in summer is the main reasons of double warm cores along the 36°N section. The intermediate cold water is formed in early spring and moves eastward slowly, which results in the formation of the western one of double cold cores. (3) Position of the thermocline dome and its intensity vary interannually, which is related to El Nino events. However, the     

Land consolidation and eco-environmental sustainability in Loess Plateau: A study of Baota district,Shaanxi province,China

Journal of Geographical Sciences - Eco-environmental sustainability is the basis for sustainable development in ecologically fragile areas. Land consolidation plays an important role in...     

氯化物中锂离子存在时EDTA质量滴定锶离子含量

锂共存时对EDTA络合滴定Sr2+离子产生较强的干扰,使分析结果偏高。根据被测液中氯化锂的大约含量,通过加入适量混合醇,可消除Li+离子的干扰,质量滴定法相对误差<0.3%。在锂锶质量比为0.100¹4.5范围内,被测样中LiCl质量与加入混合醇体积呈线性关系。混合醇掩蔽体积范围为314.5范围内,被测样中LiCl质量与加入混合醇体积呈线性关系。混合醇掩蔽体积范围为3⁵ mL。根据锂离子与水分子、短链醇形成蔟合物的键能,对消除Li+离子干扰络合滴定的机理进行探讨。