2-甲基-1,8-萘啶衍生物的甲基溴代反应

报道了2-甲基-1,8-萘啶衍生物的甲基溴化反应,以N-溴代琥珀酰亚胺(NBS)为溴化剂、红外光为引发剂,得到单溴代产物2-溴甲基-1,8-萘啶衍生物及其二溴代副产物2-二溴甲基-1,8-萘啶衍生物,对比了两种不同的反应条件,通过对影响甲基溴化产物产率的反应条件进行优化改进,得到单溴代产物的较优合成条件为：NBS的用量为原料的1.2倍,500 W红外灯为光源,反应时间为2 h。 该反应条件下,单溴代产物的产率可达到54.6%。     

高过载下桥丝式电雷管损伤和性能变化规律研究

采用空气炮在6万g、8万g、10万g和12万g高过载环境下对制式桥丝式独角和双脚线电雷管进行实验,讨论了加速度峰值、加载方向和产品结构对损伤和性能的影响,获得了高过载下的损伤规律和损伤模式,结合产品结构用动力学理论进行了分析。研究表明：损伤模式有局部塑性变形、相对位移和结构脆性破坏,表现为撞击端变形、电极塞内陷、电极和脚线倾斜、电极塞裂纹、电阻增大、桥丝断裂、输出威力散布增大。输出端加载时长度变化率随加速度增加而增大,独角雷管长度减小由电极塞内陷引起,双脚线雷管长度减小由撞击端变形导致;独角雷管横向加载时电阻变化显著,发生断桥和爆炸;过载后输出威力散布增大。     

Investigation of sulfur speciation in particles from small coal-burning boiler by XANES spectroscop

Sulfur K-edge X-ray absorption near-edge structure （XANES） spectroscopy was employed to study the speciation of sulfur in raw coal, ash by-product and fine particulate matter from a small coal-burning boiler. By means of least square analysis of the XANES spectra, the major organic and inorganic sulfur forms were quantitatively determined. The results show that about 70% of the sulfur in raw coal is present as organic and a minor fraction of the sulfur occurs as other forms： 17% of pyrite and 13% of sulfate. While in bottom ash, fly ash, and PM2.5, the dominant form of sulfur is sulfate, with the percentage of 80,79 and 94, respectively. Moreover, a number of other reduced sulfur including thiophenic sulfur, element sulfur and pyrrhotite are also present. During coal combustion, most of organic sulfur and pyrite were oxidized and released into the atmosphere as SO2 gas, part of them was converted to sulfate existing in coal combustion by-products, and a small part of pyrite was probably reduced to elemental sulfur and pyrrhotite. The results may provide information for assessing the pollution caused by small boiler and developing new methods for the control of SO2 pollution.     

Characteristics of element concentration of daytime and nighttime PM2.5 in the suburbs of Shanghai using Synchrotron XRF

The characteristics of daytime and nighttime suburbs PM_2.5 in Shanghai were analyzed by synchrotron based X-ray fluorescence during the period of October, 2006 and November, 2007. The mass concentrations of nighttime PM_2.5 was approximately two times that of daytime PM_2.5. Some elements, such as Zn, Cu, Mn, Cl were found enriched at night. The local sources might have significant contribution to the nighttime PM_2.5 pollutions.     

Transfer characterization of sulfur from coal-burning emission to plant leaves by PIXE and XANES

The impact of coal-burning emission on sulfur in camphor leaves was investigated using Proton Induced X-ray Emission (PIXE) and synchrotron radiation technique X-ray Absorption Near-Edge Structure (XANES) spectroscopy. The PIXE results show that the sulfur concentrations in the leaves collected at the polluted site are significantly higher than those in controls. The Sulfur XANES spectra show the presence of organic (disulfides, thiols, thioethers, sulfonates and sulfoxides) and inorganic sulfur (sulfates) in the leaves. The inorganic sulfur in the leaves of camphor tree polluted by coal combustion is 15% more than that of the control site. The results suggest that the long-term coal-burning pollution resulted in an enhanced content of the total sulfur and sulfate in the leaves, and the uptake of sulfur by leaves had exceeded the metabolic requirement of plants and the excess of sulfur was stored as SO₄^2－. It can monitor the sulfur pollution in atmosphere.     

2D NMR技术在石油测井中的应用

近几年,2D NMR技术得到迅速发展,特别是在核磁共振测井领域. 该文将主要介绍2D NMR技术的脉冲序列、弛豫原理以及2D NMR技术在石油测井中应用. 2D NMR技术是在梯度场的作用下,利用一系列回波时间间隔不同的CPMG脉冲进行测量,利用二维的数学反演得到2D NMR. 2D NMR技术可以直接测量自扩散系数、弛豫时间、原油粘度、含油饱和度、可动水饱和度、孔隙度、渗透率等地层流体性质和岩石物性参数. 从2D NMR谱上,可以直观的区分油、气、水,判断储层润湿性,确定内部磁场梯度等. 2D NMR技术为识别流体类型提供了新方法.     

GdBaCo2O5+δ体系的滞弹性内耗研究

GdBaCo2O5+δ体系的低频内耗研究表明:体系中存在一个由额外氧运动引起的弛豫内耗峰;额外氧δ对这个弛豫内耗峰的大小、峰形及峰位有较大影响,反映了额外氧状态随δ而变化.当δ=0.005,体系中额外氧含量很少而接近零时,相应的内耗峰消失;δ达到一定数量后,出现弛豫内耗峰.由δ=0.278,0.407,0.421,0.515样品的弛豫内耗峰分析可得到体系随δ不同存在着三种不同的额外氧形态.此外,δ=0.421及0.515的样品在360K附近存在一个相变内耗峰,它对应着体系中的金属-绝缘体转变.     

高频溅射法制备Bi—Sr—Ca—Cu—O超导薄膜

以单晶 YSZ、YAG 为衬底,用高频溅射法制备了 Bi-Sr-Ca-Cu-O 超导薄膜,膜厚为0.5—1μm,其中两个样品的超导性能为 T_c(onset)=92K,T_c(mid)=78K,T_(ce)=42K 和T_c(onset)=95K,T_c(mid)=78K,T_(ce)=36.5K,经分析,后者的组成近似地为Bi_2Sr_2Ca_1Cu_2O_x.对靶组分、溅射和热处理条件与生成的膜成分、物相、形貌以及超导电性的关系做了讨论.     

国家自然科学基金项目选题论证中的几个原则

本文论述了基础研究选题中的创新性、需要性和协作性等三个原则．这也是提高申请质量的三个措施．     

冷原子荧光光谱法测定3种中药材中的痕量汞

采用硝酸-双氧水体系及高压消解法处理样品,建立了氢化物发生-冷原子荧光光谱法测定中药材中的痕量汞的测定方法,研究了仪器工作条件、介质酸及浓度、还原剂硼氢化钾浓度对测量结果的影响并进行了优化,在最佳实验条件下对3种云南产地中药材进行了测试,汞的校准曲线在0—10μg.L-1范围内线性良好,相关系数为0.9999,方法的检出限为2.9ng.L-1,RSD为1.8%,测定的3种中药材中的汞含量为5.62—17.29ng.-g 1,加标回收率为90.3%—105.2%。