改进原子吸收分光光度计的输出显示

采用7107A/D转换器,将原子吸收分光光度计指针式显示改为数字化显示,给出了改进方法,介绍了7107A/D转换器及显示电路原理.通过改进提高了仪器输出读数的分辨率和灵敏度.     

悬浮进样石墨炉原子吸收法测定纳米氧化锆粉体中的微量铝

采用水介质直接分散纳米氧化锆粉体悬浮进样，以水标准溶液绘制校正曲线，石墨炉原子吸收法测定其中的微量Al。系统研究了Al的原子化和灰化行为，不同分散介质及基体元素对测定Al的影响，获得了测定Al的优化条件。方法对Al的检测限为0．5ng／g，Al的线性范围为0～2．5mg／L，基体ZrO2的质量浓度小于2g／L时，对Al的测定无干扰，悬浮进样直接测定的RSD(n=5)为6．0％。样品的测定结果与其他方法对比基本一致。     

复合地基垫层的减振作用分析

从垫层桩基的减振机理出发，分析了垫层桩基和复合地基的等效性，提出了复合地基的减振机理和减振动力模型。复合地基的减振性能主要体现在减小振幅、粘滞阻尼耗能和摩擦耗能上。根据复合地基的减振机理，可把基础和垫层简化为多自由度的质、阻、弹振动体系，同时考虑滑动摩擦作用。最后，提出了按减振思想设计和施工复合地基的要求。     

DOAS Zenith Sky Observations: 1. BrO Measurements over Bremen (53°N) 1993–1994

Observations of stratospheric BrO over Bremen (53°N) are reported for winter and early spring periods of 1993 and 1993/94. The BrO was observed by ground-based near-UV absorption spectroscopy of sunlight scattered in the zenith. Differential slant column densities for solar zenith angles 90°/80° in the range of9× 10¹³ (detection limit) to 4.5×10¹⁴ molecules/cm² having a high day-to-day variability were found. For the majority of the measurements no significant difference was observed between the morning and evening behaviour of BrO. Exceptions are the morning measurements from the winter of 1992/93 where an accelerated production of BrO was observed. We believe the latter best to be explained by the early morning rapid photolysis of elevated amounts of photo-labile Br-reservoirs formed during the night. The largest differential slant column densities of BrO were measured in December 1993 when the temperatures at 30 hPa dropped below 205 K. This might be an indication of heterogeneous conversion of bromine compounds on sulfate and other aerosols.     

光谱增感染料的结构与其光谱吸收

增感染料在摄影、印刷制版等领域中的应用是十分广泛的，增感染料可以使感光材料的感光度提高，可以改善和扩大其感色性和画面层次等。增感染料的增感效率与其光吸收有着直接的关系，而增感染料的光吸收作用又受到其结构的影响。本文分析了增感染料的结构对其光谱吸收的影响。     

Simulating Experiments on Enrichment of Gold by Bacteria and Their Geochemical Significance

The experiments on the enrichment of gold by bacteria indicate that bacteria have a very intense capacity of enriching gold and act as an arrester of trace gold in sea water,Bacteria enrich gold in two forms:absorption and adsorption.Absorption means that gold finds its way into organisms and it is combined with the mercapto group of protein,whereas adsorption means that gold is adsorbed on organisma by amino acid secreted by cell walls,Bacteria are organisms with very high vitality and reproductive capacity and huge productivity in nature Bacteria,which are important geolgical agents for gold enrichment and can exert effects on geological environments by their metabolism,are of important geochemical significance for the formation of gold-bearing black rock series.     

Research on coda Q distribution in Beijing and its surrounding regions

Based on the single scattering model of seismic coda waves, we have calculated theQ-factor in Beijing and its surrounding regions by means of calculating the power density spectrum in frequency domain with a fixed time window. The digital seismic data of 69 earthquakes from Beijing Telemetered Seismographic Network are used. These earthquakes were recorded from January 1, 1989 to December 31, 1990 at 20 stations. This paper shows the variations of the codaQ-factors in the studied region with different sites, frequency and lapse time, and the temporal change of the codaQ-factors in these two years. The results indicate that codaQ-factor depends strongly on the lapse time and frequency. It is assumed that whenQ _C=Q ₀f^η, for the three time windows of 15–30s, 30–60s and 60–90s, the average values ofQ ₀ are 48, 115 and 217; and the average values ofη are 0. 89, 0.91 and 0.74, respectively. Contribution No. 95A0009, Institute of Geophysics, SSB, China. This work is a contract subject 85-04-01-02 of the State Seismological Bureau, China.     

中国地区近地面太阳紫外辐射的分布及其对大气臭氧层破坏的响应

本文在充分考虑太阳紫外辐射在大气中传输的物理过程的基础上,引入局地地面气压、臭氧和地表反照率的时空变化,利用Delta-Eddington近似法计算了中国地区冬季(1月)和夏季(7月)晴天时地面太阳紫外辐射(0.290—0.400μm)和紫外B辐射(0.290—0.325μm)的分布,并进一步计算出臭氧总量减少5％、15％时紫外B的变化.结果指出,由于臭氧总量的减少,中国北部地区紫外B的增加比南部地区显著.平均而言,臭氧总量减少1％时,冬季紫外B将增加1％左右,夏季紫外B将增加0.6％—0.7％.