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1.
Irvine WM Friberg P Hjalmarson A Ishikawa S Kaifu N Kawaguchi K Madden SC Matthews HE Ohishi M Saito S Suzuki H Thaddeus P Turner BE Yamamoto S Ziurys LM 《The Astrophysical journal》1988,334(2):L107-L111
We report the astronomical identification of the cyanomethyl radical, CH2CN, the heaviest nonlinear molecular radical to be identified in interstellar clouds. The complex fine and hyperfine structures of the lowest rotational transitions at about 20.12 and 40.24 GHz are resolved in TMC-1, where the abundance appears to be about 5 x 10(-9) relative to that of H2. This is significantly greater than the observed abundance of CH3CN (methyl cyanide) in TMC-1. In Sgr B2 the hyperfine structure is blended in the higher frequency transitions at 40, 80, and 100 GHz, although the spin-rotation doubling is clearly evident. Preliminary searches in other sources indicate that the distribution of CH2CN is similar to that for such carbon chain species as HC3N or C4H. 相似文献
2.
Using the National Center for Enviromental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data and NOAA satellite-obser ved outgoing long-wave radiation (OLR) data, the development of the South China Sea (SCS) summer monsoon and intraseasonal (30-60 d) oscillation (ISO) have been examined. The results show that there exists obvious interannual variability of intraseasonal oscillaiton. Using the 16 a time series of filtered OLR averaged over the SCS, an index is defined to define ““onset events““ over the SCS on the ISO time scales. Of the 16 a examined here, 10 shows a strong ISO signal in the onset of monsoon convection over the SCS. In these cases, the ISO initially suppresses the seasonal development of southwesterly and cyclonic circulation over the SCS before the ISO onset. As the ISO propagates northeastward, the low frequency cyclonic circulation anomaly occurs in the SCS and the low frequency southwesterly wind and convection over here dramatically intensify. The northeast progression of the ISO anomaleis plays a role in the initial suppression and then acceleration of the seasonal cycle of the SCS summer monsoon. 相似文献
3.
Gene specific primers and DNA probe were designed based on the sequence of 18S rDNA cloned from the red tide alga Thalassiosira rotula. A real-time fluorescent quantitative PCR (RFQ-PCR) method was developed for quantitative detection of T.rotula. The RFQ-PCR assay data showed that the results obtained with the RFQ-PCR quite good agreement with those with the light microscope (LM) counting method, which suggested that the RFQ-PCR could be a useful method for red tide alga detection. 相似文献
4.
Kun HE Yuming DONG Lin YIN Aiming ZHANG Zhen LI 《中国地球化学学报》2006,25(B08):101-101
Catalytic ozonation has attracted much attention in treatment of wastewater for its mild conditions. Phenol and its ramifications are common components in a wide variety of wastewaters including those from coal conversion processes, coking plants, petroleum refineries and several chemical industries. In this paper, natural brucite and magnesia have been successfully used in catalytic ozonation of phenol. And the mechanisms of catalysis were also investigated. From Figs. 1 and 2, it can be found that both brucite and magnesia have remarkable catalysis on degradation of phenol and removal of Chemical Oxygen Demand (COD). The pH of solutions on the process of ozonation alone, catalytic ozonation with brucites and with magnesia were 6.35-2.76, 10.18-8.52 and 10.58-10.83, respectively. It can be concluded that alkali environment plays a critical role for catalytic ozonation of phenol. We also found that the alkaline minerals reacted on the surface with oxalic acid and other low molecular-weight acids which are intermediate products in ozonation, but those intermediate products could be mineralized into carbon dioxide completely with enough ozonation time. 相似文献
5.
Chunye LIN Mengchang HE Baixing YAN Xiangchun QUAN Yuxiang ZHOU Wei GUO Zhifeng YANG 《中国地球化学学报》2006,25(B08):118-119
The Second Songhua River was subjected to a large amount of untreated effluent from petrochemical industries in Jilin City in the 1960s to the 1970s. The objectives of this study were to investigate the mercury and other heavy metal contamination in the sediment of the river. The river bottom sediment was sampled from the river segment between Jilin City to Haerbin City in 2005. Total concentrations of Hg, Cd, Cu, Cr, Pb, Zn, Ni, As, Sc, and major cations (A1, Fe, Mg, Ca, K, Na) in the sediment were measured by atomic fluorescence spectrometer, ICP-MS, and ICP-OES, respectively, following digestion with various acids. We found the concentrations of most elements in the uncontaminated sediment were significantly correlated to those of Sc. 相似文献
6.
Weiyang BAI Xinbin FENG Xuewu FU Tianrong HE Guangle QIU 《中国地球化学学报》2006,25(B08):154-154
In order to find out whether Aha Lake was polluted by the acid mining waste water or not, the concentration and distribution of different mercuryspecies in the water columns and sediment profile collected from Aha Lake were investigated. It was found that discernible seasonal variation of different mercury species in water body were obtained in the Aha Reservoir. With regards to the whole sampling periods, the concentrations of HgP in the Aha Reservoir water body were evidently correlated to the concentrations of total mercury, showing that total mercury was mostly associated with particle mercury. The concentrations of methylmercury in water body were also evidently correlated to the concentrations of dissolved mercury. The dissolved mercury evidently affects the distribution and transportation of methylmercury. However, there is no correlation between methylmercury and total mercury. The dissolved mercury, reactive mercury, dissolved methylmercury levels in the water body of high flow period were much higher than those in low flow period. The distribution, speciation and levels of mercury within the Aha Reservoir water body were governed by several factors, such as the output of river, the release of sediment . Discernible seasonal variation of total mercury and methylmercury in porewater was described during the sampling periods, with the concentrations in high flow period generally higher than those in low flow period. The methylmercury in pore water column was evidently correlated to that of the sediment. The results indicated that highly elevated MeHgD concentrations in the porewater were produced at the depths from 2 to 5 cm in the sediment profile, and decreased sharply with depth. A positive correlation has been found between MeHgD formation and sulfate reducing bacterial activity. These highly elevated concentrations of MeHgD at the intersurface between waters and sediments suggest a favorable methylation condition. Moreover, 相似文献
7.
Treatment of high fluoride concentration wastewater by layered double hydroxides: Mechanism studies 总被引:1,自引:0,他引:1
Liang LU Jing HE 《中国地球化学学报》2006,25(B08):160-161
An appropriate concentration of fluoride in drinking water is required to prevent dental cavities, but long-term ingestion of water that contains more than a suitable level of fluoride can cause bone disease and mottling of the teeth. Fluoride ions can be found in wastewater from the fluoride chemical industry, as well as the semiconductor, metal processing, fertilizer, and glass-manufacturing industries. The discharge standard for fluoride in industrial wastewater in China is 10 mg/L. Efficient treatment of fluoride-containing wastewater is therefore of major concern in China, following the rapid development of the fluoride chemical industry. Several methods have been used to remove fluoride from water, such as adsorption, chemical precipitation, electrodialysis, ion exchange and electrochemical processes. Layered double hydroxides (LDHs) are anionic clays with high anion exchange capacities which are effective adsorbents for removal of a variety of anionic pollutants. LDHs have been studied as potential adsorbents for removing toxic anionic species such as CrO4^2-, TcO4^-, SeO3^2-, pesticides, and anionic surfactants from aqueous systems. One of the main attractions of using LDHs for fluoride removal, is that unlike other chemical treatment methods, no chemical sludge should be produced. In the present study, an attempt was made to investigate the mechanism of fluoride removal by LDHs under different conditions using batch methods. In addition, the release of fluoride adsorbed on LDHs by treatment with an aqueous solution of Na2CO3 was studied. The residual fluoride was found to be 10 mg/L in a solution with an initial concentration of 1000 mg/L, which meets the discharge standard for fluoride in industrial wastewater in China. 相似文献
8.
土壤干湿交替促进硒酸盐的还原作用 总被引:3,自引:0,他引:3
采集不同类型的新鲜土壤,经处理获得其风干、烘干的样品,重新潮湿后,加入一定量的Na2SeO4溶液,进行了培育实验(incubationexperiments)。实验结果表明,随着土壤干燥程度的增加,硒酸盐还原作用的速度也随之加快。这进一步证实,作为一种地球化学营力的土壤干湿交替,通过对土壤水势(soilwaterpotential)、微生物群落等的影响,间接地促进了硒酸盐还原作用,因而成为硒生物地球化学循环的驱动力之一。 相似文献
9.
10.
1. IntroductionAccording to the reconstruction of paleo-temperature based on δ18 O data of ice core in theGreenland (see Jouzel et al., 1987; Grootes et al.,1993; Blunier and Brook, 2001), the current inter-glacial epoch, the Holocene, began at ca. 11.5 thou-sand years before present (ka BP). Multiple sources(pollen data, macrofossils) reveal that the summer cli-mate in the Northern Hemisphere was warmer in theearly to middle Holocene (MH) (ca. 8-6ka BP) relativeto the present climate. … 相似文献