On the role of climate in desertification of the Sahel Belt

Ｉｎｔｈｅｐａｓｔ20ｏｄｄｙｅａｒｓ,ｔｈｅｒｅｈａｓｃｏｍｅｕｐａｗｏｒｌｄｗｉｄｅ,ｂｒｏａｄｓｃａｌｅｍｏｖｅｍｅｎｔｔｏｃｏｍｂａｔｄｅｓｅｒｔｉｆｉｃａｔｉｏｎ.ＴｈｅｐｒｏｂｌｅｍｏｆｄｅｓｅｒｔｉｆｉｃａｔｉｏｎｈａｓｂｅｅｎｌｉｓｔｅｄｂｙｔｈｅＵＮａｓｏｎｅｏｆｔｈｅｇｌｏｂａｌｐｒｏｂｌｅｍｓｏｆｇｒｅａｔｓｉｇｎｉｆｉｃａｎｃｅｔｈａｔ“ａｌｍｏｓｔａｌｌｔｈｅｃｏｕｎｔｒｉｅｓｉｎｔｈｅｗｏｒｌｄａｒｅｉｎｖｏｌｖｅｄｉｎ.“Ａｌｌｔｈｅｓｅａｒｅｒｅｌｅｖａｎｔｔｏａｎｏｒ…     

水土合算法土压力计算时的强度指标

提出了水土合算时接近其实际固结状态和应力路径的强度指标公式,据此分析了常规三轴压缩指标应用时可能引起的误差.     

中国断裂构造的分形特征及其大地构造意义

中国大陆壳体中深大断裂的分布具有分形结构特征。大陆全境的分维值为1．493,各构造区的分维值为0．827～1．624。活动区特别是地洼区中断裂构造分维值（1．236～1．624）显著大于稳定区即地台区的分维值（0．827～1．074）,并且壳体结合部位的分维值大于壳内部位。断裂构造的分维值反映了区域大地构造演化、运动历史的复杂性和构造活动的强弱性,因而可作为大地构造研究的一个定量参数。     

硅胶—TBP萃取层析连续分离和测定铁（Ⅲ）,铬（Ⅵ）的研究及应用

研究以ＣＨＣｌ＝３ｍｏｌ／Ｌ作移动相,以硅胶球负荷的ＴＢＰ作固定相,反相萃取层析铁,铬,使与多种离子分离,留于柱上的铁,铬分别用ＣＨＣｌ＝０．８ｍｏｌ／Ｌ及水洗脱进行连续分离与测定,方法应用于矿物岩类复杂物质中铁,铬的连续分离与测定,简便,快速,准确。     

A Brief Discussion on the High-Impact Cold-Season Tornado Outbreak During 10-11 December 2021 in the United States

An outbreak of powerful tornadoes tore through multiple states in the central and southern United States from 10 to 11 December 2021. It is claimed the deadliest tornado outbreak that has taken place on December days. The National Oceanic and Atmospheric Administration had confirmed 66 tornadoes as of 21 December, producing at least 90 fatalities. Most tornadoes occurred at night and thus they were difficult to be visually located, which directly increases the risk for local residents. Two violent nighttime tornadoes were rated category 4 on the enhanced Fujita scale (EF4). Although a high death toll was caused during this event, the operational service actually presented an excellent performance. This tornado outbreak has aroused extensive discussion from both the public and the research community in China. This paper presents a brief discussion on the formation environment and warning services of the tornado outbreak. Recall the deadliest violent tornado in the past 45 years in China, the radar-based tornadic vortex signatures at the locations with EF4 damages show a comparable strength with those in the current cases. Some views on the tornado warning issuance and receiving and damage surveys in China are also presented.     

Spatio-temporal distribution and characteristics of PAHs in sediments from Masan Bay, Korea

The distribution of polycyclic aromatic hydrocarbons (PAHs) has been investigated in the surface and core sediments from Masan Bay, Korea. Total PAHs in the surface sediments ranged from 207 to 2670 ng/g dry weight with a mean value of 680 ng/g. Qualitative similarity and quantitative difference between inner and outer bay indicate that the main sources of PAHs are located in the inner bay and outer bay is also affected by the same sources. Vertical distribution of PAHs revealed that three distinctive stages could be differentiated with the help of PCA analysis. The highest concentration (industrialization stage) appeared between late 1950s and 1980, which was 10 years later than other developed countries. A strong pyrolytic source fingerprint has been detected with slight influence of petrogenic sources, and diagenetic PAH, perylene also contributed. Total organic carbon normalized PAHs (sum of 13 PAHs, 8.85-88.0 microg/g OC) were under the threshold effects concentration (TEC, 290 microg/g OC).     

Bioavailability of dissolved organic phosphorus compounds to typical harmful dinoflagellate Prorocentrum donghaiense Lu

The bioavailability of dissolved organic phosphorus (DOP) compounds to harmful alga Prorocentrum donghaiense Lu and its alkaline phosphatase activity (APA) were studied. Results showed that P. donghaiense could utilize the test DOP compounds such as glucose-6-phosphate (G-6-P), adenosine triphosphate (ATP) and ribonucleic acid (RNA) to sustain its growth. Nutrition between the test DOP compounds and orthophosphate was comparable. P. donghaiense could utilize intracellular phosphorus to sustain growth under depletion of dissolved phosphorus. Variation of APA in different test DOP compounds was addressed; the controlling mechanism of APA in different DOP media was discussed.     

Assessment of butyl- and phenyltin pollution in the coastal environment of Korea using mussels and oysters

Butyl- and phenyltin residues in bivalves were quantified around the coast of Korean peninsula in 1995–1998 and 2001. Butyltin compounds were detected at all the sites surveyed, whereas phenyltins were detected at 41 out of 67 sites in 1995–1998. Tributyltin (TBT) concentrations in bivalves ranged 48–2800 ng Sn/g on dry weight basis. Triphenyltin (TPT) concentrations ranged <3–1820. The mean TPT concentration was 3.5 times less than that of TBT. Spatial distribution of TBT was closely related to boating and dry-docking activities. TPT concentration in bivalves showed significant correlation with TBT. Concentrations of TBT in bivalves, 2001 are not significantly changed compared to those in 1995–1998. However, TPT concentrations in bivalves steeply decreased in 2001. High concentration of TBT and lesser extent TPT and their nation-wide distribution indicate that organotins are one of major organic pollutants in the marine environment of Korea.     

Magnetic properties of Jiaxian red clay sequences from northern Chinese Loess Plateau and its paleoclimatic significance

Rock magnetism research on eolian deposits from the Chinese Loess Plateau shows that magnetite, maghe- mite and hematite are the main magnetic minerals in loess-paleosol sequences and red clay se-quences[1―8], and finds that the magnetic susceptibility increase is positively correlated to the content of ultra-fine minerals and relatively strong pedogene- sis[7―15]. This offers significant information in studying the Late Cenozoic paleoclimatic history of Chinese Loess Plateau[1,5―8,10―22…