电感耦合等离子体发射光谱法快速测定钼铁合金中的钼

用电感耦合等离子体发射光谱法测定钼铁中的钼,优化了仪器操作条件,克服了常规重量法测定钼铁中钼步骤繁琐、耗时长、工作量大的不足。方法简便易行,快速准确,分析误差在化学分析允许的误差范围内,能替代原有的化学分析方法,基本满足生产和科研的要求。     

父权的衰微——从五·四启蒙运动谈起

在中国十九世纪末二十世纪初的启蒙运动中,启蒙思想家们将启蒙国民性的重点放在了批判儒家思想中的家族制度和家族伦理上。家族制度和家族伦理作为封建父权的安身立命之所,对它们的质疑和瓦解必然导致父权在整体上被瓦解,从此,父权走上了衰微之路。     

水中硫酸盐测定方法研究

对EDTA容量法测定水中硫酸根时，对加入沉淀剂后样品静置时间对测定结果的影响进行了研究。结果表明，在本法规定的浓度范围内，样品静置时间对测定结果无影响。     

Characterization of surface and ground water δ18O seasonal variation and its use for estimating groundwater residence times

¹⁸O is an ideal tracer for characterizing hydrological processes because it can be reliably measured in several watershed hydrological compartments. Here, we present multiyear isotopic data, i.e. ¹⁸O variations (δ¹⁸O), for precipitation inputs, surface water and groundwater in the Shingobee River Headwaters Area (SRHA), a well‐instrumented research catchment in north‐central Minnesota. SRHA surface waters exhibit δ¹⁸O seasonal variations similar to those of groundwaters, and seasonal δ¹⁸O variations plotted versus time fit seasonal sine functions. These seasonal δ¹⁸O variations were interpreted to estimate surface water and groundwater mean residence times (MRTs) at sampling locations near topographically closed‐basin lakes. MRT variations of about 1 to 16 years have been estimated over an area covering about 9 km² from the basin boundary to the most downgradient well. Estimated MRT error (±0·3 to ±0·7 years) is small for short MRTs and is much larger (±10 years) for a well with an MRT (16 years) near the limit of the method. Groundwater transit time estimates based on Darcy's law, tritium content, and the seasonal δ¹⁸O amplitude approach appear to be consistent within the limits of each method. The results from this study suggest that use of the δ¹⁸O seasonal variation method to determine MRTs can help assess groundwater recharge areas in small headwaters catchments. Copyright © 2005 John Wiley & Sons, Ltd.     

WEP的安全技术分析及AES的解决方案

在深入分析IEEE 802.11标准的有线等价私密（WEP）安全漏洞的基础上,提出了用高级加密算法AES代替RC4,AES提供了比RC4更高的加密性能和更加强大的安全保护,因此AES方案必将成为新一代的加密标准.     

基于BF533的基4 FFT算法的DSP实现

首先介绍了基4时域抽取FFT算法的快速高效的原理及实现方法, 然后用MATLAB对该算法进行了仿真,分析了对其优化的几个方向,并提出了一种利用单一倒序表进行多点数位倒序的新方法.最后给出了在ADSP-BF533 DSP 上采用C语言实现FFT 的软件设计方法,并在ADSP-BF533 KZ-KIT LiteTM评估板上成功实现,经过实验验证, 结果正确,各项指标均达到了设计要求.该实现方法具有可移植性好、速度快等优点,具有很好的参考价值和应用前景.