Tidal stress triggering effects of earthquakes based on various tectonic regions in China and related astronomical characteristics

Dividing the mainland China into different tectonic stress regions, we calculate tidal stress components along the seismic compressive and extensional principal stress axes at every earthquake’s focus in different tectonic stress regions. Tidal stress triggering effect on every earthquake fault is analyzed. Based on this, the lunar-solar location parameters on the occurring times of earthquakes which suffered tidal triggering effects are calculated, and the distribution patterns of the lunar-solar location parameters in different tectonic stress regions are obtained. The results indicate that earthquake tidal triggering effects and related astronomical characteristics are dependent on the properties of regional tectonic stress and the geographic locations of earthquake faults. Supported by the National Natural Science Foundation of China (Grant No. 40764001)     

Chinesisch‐Deutsches Symposium ”Frontiers of Chemistry“

Die Chinesische Chemische Gesellschaft und die Gesellschaft Deutscher Chemikerorganisierten das zweite Symposium ”Frontiers of Chemistry“ vom 5. bis 11. Oktober 2008 in China.     

DDQ-promoted direct C–H amination of ethers with N-alkoxyamides under visible-light irradiation and metal-free conditions

A C(sp³)–N bond forming reaction between N-alkoxyamides and simple ethers has been developed. In the presence of commercially available 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), a variety of N-methoxyamides and ethers undergo this transformation smoothly to deliver the corresponding products in good yields under visible-light irradiation and metal-free conditions at room temperature.     

Iodine-mediated one-pot synthesis of C-3 acylated indolizines from pyridines,aryl methyl ketones and acrylate derivatives

An I₂/CuI-promoted multi-component reaction from pyridines, aryl methyl ketones and electron deficient acrylates has been accomplished in a “one-pot” manner, which provides a straightforward and efficient access to C-3 acylated indolizines. The key intermediate of N-ylides is hypothesized to be generated in situ from pyridines and (hetero)aryl methyl ketones in the presence of iodine. This method has been applied in the synthesis of two molecules with anticonvulsant and anti-inflammatory activities.     

Asymmetric transfer hydrogenations of β-N-substituted enamino esters with ammonia borane

Optically active β-amino acids and their derivatives are very useful building blocks in synthetic and medicinal chemistry. The catalytic asymmetric reduction of β-enamino esters is one of the most efficient approaches for their synthesis. Ammonia borane with low molecular weight, high hydrogen capacity, and good stability, is an ideal hydrogen source for the transfer hydrogenation. However, only a few successful examples have been reported for the asymmetric reduction with ammonia borane. In this work, an asymmetric metal-free transfer hydrogenation of β-N-substituted enamino esters with ammoinia borane was successfully realized by using a frustrated Lewis pair of Piers’ borane and (S)-tert-butylsulfinamide as a chiral catalyst. A variety of β-amino acid derivatives were obtained in 51–90% yields with up to 91% ee.     

Characterization of summer PM2.5 aerosols from four forest areas in Sichuan,SW China

Aerosol samples were collected over 24 and 12 h to represent day/night aerosol characteristics in forest areas at Ya’an Baima Spring Scenic Area (BM), Panzhihua Cycas National Nature Reserve (PZ), Gongga Mountain National Nature Reserve (GG), and Wolong National Nature Reserve (WL), during the summers of 2010–2012. Mass and chemical component concentrations, including organic carbon, elemental carbon, and inorganic ions (F⁻, Cl⁻, NO₂⁻, NO₃⁻, SO₄²⁻, C₂O₄²⁻, PO₄³⁻, K⁺, Na⁺, Ca²⁺, Mg²⁺, and NH₄⁺), of PM_2.5 aerosols were measured. The average PM_2.5 concentrations for 24 h were 72.42, 104.89, 20.55, and 29.19 μg/m³ at BM, PZ, GG, and WL, respectively. Organic matter accounted for 38.0–49.3%, while elemental carbon accounted for 2.0–5.7% of PM_2.5 mass. The sum concentrations of SO₄²⁻, NH₄⁺, and NO₃⁻ accounted for 23.0%, 17.4%, 22.1%, and 30.5% of PM_2.5 mass at BM, PZ, GG, and WL, respectively. Soil dust was also an important source of PM_2.5, accounting for 6.3%, 17.0%, 10.4%, and 19.1% of PM_2.5 mass at BM, PZ, GG, and WL, respectively. These reconstructed masses accounted for 75.9–102.0% of PM_2.5 mass from the four forest areas of SW China.     

乘着MOOCs歌声的翅膀——复旦大学陆昉副校长访谈录

复旦大学陆昉副校长谈MOOCs实践与大学教学质量提高.他指出MOOCs大量优质资源的共享对当前大学教学质量提高具有现实意义,学校、教师、学生三方面都应该积极应对,并讲述了他在教学中运用混合式教学模式的具体教学案例.     

基于幂律尾指数研究中国降水的时空演变特征

基于中国气象局国家气候中心740站点1960—2000a的日降水观测资料，对中国各地区日降水量分等级进行统计分析，揭示了各地区日降水存在的一个共同特征——幂律尾分布，且不同等级的降水量对应不同的幂律尾指数，在一定程度上反映了不同雨型具有不同的气候背景和物理机理.中国华北、华南等七个气候特征区，其幂律尾指数总体自东南向西北呈递增趋势，这与中国降水东多西少，南多北少的空间分布特征相符合.研究各气候特征区日降水的幂律尾指数随时间的演变特征发现：东北、华北和西北地区的幂律尾指数发生突变的年份对应着20世纪70年代末开始的中国北方干旱化进程，导致的可能原因是微量降水，尤其是0—7mm日降水的减少. 关键词： 幂律尾指数 突变 北方干旱化     

Effects of urban morphology on the traffic noise distribution through noise mapping: A comparative study between UK and China

Due to the rapid urban development and massive population increase in many eastern cities, the difference in urban density and morphology between typical western and eastern cities is becoming significant. This consequently makes the noise distribution in the eastern cities rather different from typical low density European cities. In this research, two representative cities with different urban densities, Greater Manchester in the UK and Wuhan in China, were selected, which have low and high average urban density respectively, and also have considerable differences in building form and traffic pattern. In the mean time, these two cities have similar urban scale and traffic amount. In each city, based on the urban morphological analyses considering urban land-use, building and road density, and noise source distribution, a number of typical urban areas, 500 * 500 m² each, were sampled. A noise-mapping software package was then used to generate generic noise maps, based on existing digital vector maps for terrain and building, and traffic data obtained by on-site measurements. The comparison results show that the average and minimum noise level in Greater Manchester samples is generally higher than that in Wuhan samples, while the maximum noise level in Wuhan samples is mostly higher. By developing a Matlab program, correlations have been analysed between noise distributions and the urban characteristics relating to urban density, such as the road and building coverage ratio. Overall, comparisons between these two typical cities have shown significant effects of urban morphology on the traffic noise distribution.     

国内银的分析测定研究进展（一）——国内光度法测定银的研究进展

归纳总结了国内主要刊物上所发表的光度法测定银的研究和应用情况。主要包括普通吸光光度法,催化光度法,共振散射法,和化学发光法,并进一步提出了建议和设想。