巴基斯坦恰希玛核电站用 P300 工程核级离心通风机抗震性能计算及试验研究

核电中的结构、设备的安全可靠性是公众所关注的焦点，国内外的研究人员对此做了大量的工作。然而，对于多种不同的荷载组合，针对某一类结构进行细致的分析研究是必要的。本文对巴基斯坦恰希玛核电站中采用的离心通风机在地震动、转子离心力、结构内压及自重等多种荷载组合作用下对结构进行如下几项分析：（１）对结构建立有限元计算模型，并通过大型振动台试验验证模型的合理性与准确性；（２）减振后结构的动力特性研究。     

闪锌矿中杂质Fe存在形式的重新认识

闪锌矿作为一种重要的金属硫化物已得到广泛的研究，但在对闪上矿中杂质Ｆｅ存在形式的认识上却存在许多问题。本文对不同含Ｆｅ量的天然闪锌矿测定并分析了Ｆｅ的Ｋ边ＥＸＡＦＳ谱，同时对低温光吸收谱及穆斯堡尔进行了研究。结果表明，Ｆｅ在闪锌矿中主要以六配位形式存在。     

The NO2 absorption spectrum. II. Absorption cross-sections at low temperatures in the 400–500 nm region

With improved experimental conditions already used for measurements at ambient temperature (Mérienneet al., 1994), new values have been found for the absorption cross-sections of NO₂ at 240 and 220 K in the 400–500 nm spectral region. Using a better resolution than in previous studies we show that the temperature effect is not negligible and should be taken into account for the optical measurements of atmospheric NO₂ amounts by differential absorption methods.Unité de Recherche Associée au CNRS.     

Doppler detection of hydroxyl column abundance in the middle atmosphere

The hydroxyl column abundance in the middle atmosphere is measured with ground-based uv spectroscopy using the sun as a light source. The present method is distinctive in that it utilizes the Doppler shift of the solar spectrum due to the solar rotation to discriminate the slight terrestrial hydroxyl absorption from prominent solar features. By comparing the spectra measured on the east and the west edges of the solar disk, it is possible to cancel out most of the solar structures and to make the terrestrial features much more evident.     

Z-2000偏振塞曼石墨炉原子吸收分光光度计测定地球化学样品中痕量金

用φ=50%的王水分解样品,聚氨酯泡沫塑料吸附富集金,10g/L硫脲为解脱剂,偏振塞曼石墨炉原子吸收分光光度计测定痕量金。对干燥、灰化、原子化、净化温度和时间,以及载气流量和灯电流强度进行了讨论;对影响金吸附效果的泡塑载体和王水浓度等因素进行了研究。通过实验得到了Z-2000偏振塞曼原子吸收分光光度计最佳石墨炉分析测试条件。方法检出限为0.3ng/g,回收率为95.0%~101.0%,精密度(RSD,n=12)低于8.0%,经国家一级标准物质(GBW07243~GBW07245)分析验证,结果与标准值相符。     

火焰原子吸收光谱法测定天青石中锶

将天青石试样经混合熔剂熔融,使锶转化为碳酸盐,水提取,过滤分离硫酸根离子,沉淀用盐酸溶解,加入聚乙醇,加热煮沸,稀释至一定体积。分取部分溶液于0.4mol/L硝酸介质中,加镧盐为释放剂,原子吸收光谱法(空气-乙炔火焰方式)测定氧化锶。方法适用于天青石中w(SrO)≤50%氧化锶的测定。     

快速标准加入无火焰原子吸收光谱法测定人血和动物血中铅和镉

用快速简便的标准加入无火焰原子吸收光谱法测定人血和动物血中有害元素铅和镉.与普通的标准加入法相比,此法在样品前处理、标准曲线绘制及样品结果计算上都有了很大的简化.方法检出限为铅2.00μg/L,镉0.30μg/L;回收率为铅99.5%～101.2%,镉99.7%～101.3%;精密度为铅0.95%,镉2.18%.方法灵敏度高,精密度好,适用于特定人群血液中铅和镉含量的普查.     

Crystal field and covalency of octahedral chromium in natural [8](Mg1?xCax) 3[6] (Al0.67Cr0.33)2Si3O12 garnets from upper mantle rocks

In the course of a thorough study of the influences of the second coordination sphere on the crystal field parameters of the 3d ^N -ions and the character of 3d ^N –O bonds in oxygen based minerals, 19 natural Cr³⁺-bearing (Mg,Ca)-garnets from upper mantle rocks were analysed and studied by electronic absorption spectroscopy, EAS. The garnets had compositions with populations of the ^[8] X-sites by 0.881 ± 0.053 (Ca + Mg) and changing Ca-fractions in the range 0.020 ≤ w _Ca[8] ≤ 0.745, while the ^[6] Y-site fraction was constant with x _Cr³⁺ _[6] = 0.335 ± 0.023. The garnets had colours from deeply violet-red for low Ca-contents (up to x _Ca = 0.28), grey with 0.28 ≤ x _Ca ≤ 0.4 and green with 0.4 ≤ x _Ca. The crystal field parameter of octahedral Cr³⁺ 10Dq decreases strongly on increasing Ca-fraction from 17,850 cm⁻¹ at x _Ca[8] = 0.020 to 16,580 cm⁻¹ at x _Ca[8] = 0.745. The data could be fit with two model which do statistically not differ: (1) two linear functions with a discontinuity close to x _Ca[8] ≈ 0.3,

科尔沁沙地几种常见植物茎叶吸水特征

植物通过茎叶吸水能够极大地改善自身水分条件。为研究科尔沁沙地植被茎叶吸收水分变化特征,于2017年7-8月选取科尔沁沙地常见植物差不嘎蒿（Artemisia halodendron）、小叶锦鸡儿（Caragana microphylla）、猪毛菜（Salsola collina）,通过自然降雨、茎叶隔雨、根部隔雨的控制试验,运用压力室法测定了降雨前后的植物水势（Ψ）变化。结果表明：（1）根部隔雨试验中,差不嘎蒿、小叶锦鸡儿和猪毛菜降雨后的水势值与降雨前相比分别升高了约66.7%、59.5%和87.9%,在降雨后第2天的水势值与降雨前相比分别升高了约73.2%、86.7%和90.6%。（2）差不嘎蒿和猪毛菜在不同部位隔雨试验中的茎叶水势值差异不明显（P>0.05）,小叶锦鸡儿茎叶水势值存在显著差异（P<0.05）。（3）差不嘎蒿、小叶锦鸡儿和猪毛菜都存在茎叶吸水现象。小叶锦鸡儿比差不嘎蒿和猪毛菜更能够适应科尔沁沙地的生存环境。