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851.
中国金红石矿床成矿地质条件及成矿远景 总被引:1,自引:0,他引:1
中国金红石矿床成因类型不一,控矿因素各异。通过对地层、构造(包括大地构造环境及褶皱)等控矿因素,区域变质作用、岩浆作用、热液作用、风化及沉积作用等成矿地质条件及矿床分布等规律的归纳与研究,提出了陕西石泉-镇坪、陕西丹凤-西峡、河南南召-方城、湖北枣阳-河南新县、湖北英山-潜山、江苏徐州-东海、山东栖霞-荣城、山西代县-河北涞水、四川会东9个金红石成矿远景区。并圈定出山东省荣城曲家、安徽凤阳板桥、湖北郧西土门—涧池、湖北七里坪大悟仙山、山西代县义成沟—羊廷寺、河北涞源司各庄、河北丰宁黄土梁等7个找矿靶区。 相似文献
852.
Contents of heavy metals, polycyclic aromatic hydrocarbons (PA Hs), dichlorodiphenyltrichloroethanes (DDTs) and hexachlorcy- clohexanes (HCHs) in surface sediments from mangrove areas of the Leizhou Peninsula were analyzed in July and November 2005. Risk assessment criteria applied by Long E R et al. (1995) and Long E D et al. (1995) (effects range low, ERL; effects range mean, ERM) of chemicals in sediments from the gulf or estuary were used to assess the potential ecological risks of heavy metals, PAHs, DDTs and HCHs to aquatic organisms in the studied area. The results indicated that the average contents of zinc, nickel, chromium, lead, copper, arsenic and mercury were (61.97 ± 55.87), (59.99 ± 39.01 ), (47.93 ± 28.37), (26.64± 13.00) , (23.45 ± 41.96), (9.32 ± 3.62), (0.14 ± 0.18) mg/kg in dry weight in the sediment samples col- lected from five studied sites in the Leizhou Peninsula, respectively. Cadmium was not calculated due to its content being below the detection limit ( 〈 0.3 mg,/kg). The average levels of Cr, Cu, Ni, Pb, Zn and Hg exceed their background values. The average contents of Ni were higher than ERM. The contents of PAHs in the sediments from the five studied sites were (79.78 ± 43.70) ng/g in dry weight, far lower than ERL(4 022 ng/g). The contents of DDE, DDD and DDTs in the sediments from five studied sites were (2.60 ± 4.68), ( 17.52 ± 27.25 ), (27.78 ± 46.64) ng/g in dry weight respectively, clearly higher than ERL, and the average contents of DDT were (7.66 ± 15.93) ng/g in dry weight, much higher than ERM. HCHs could be detected in the sediments only from Gaoqiao sampling site, with the average contents (0.07 ± 0.08) ng/g in dry weight. 相似文献
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Aim to linking the variability of drought in northwest China to the oceanic influence of North Atlantic SSTs at the background of global warming and at the regional climate change shifting stages, year aridity index variations in northwest China and summer North Atlantic sea surface temperature (SST) variations are examined for the 44 a period of 1961-2004 using singular value decomposition (SVD) analysis. Results show that the SST anomalies (SSTA)in the North Atlantic in summer reflected three basic models. The first SVD mode of SST pattern shows a dipole - like variation with the positive center located at southwest and negative center at northeast of extratropical North Atlantic. And it strongly relates to the positive trend in AI variation in northwest China. The second coupled modes display the coherent positive anomalies in extratropical North Atlantic SST and the marked opposite trend of AI variability between north and south of Xinjiang. In addition, the lag correlation analysis of the first mode of SSTA and geopotential heights at 500 hPa variations also shows that the indication of the former influencing the latter configuration, which result in higher air temperature and less precipitation when the SSTA in the North Atlantic Ocean in summer motivated Eurasian circulation of EA pattern, further to influence the wet - dry variations in northwest China by the ocean-to - atmosphere forcing. 相似文献
855.
Dissolved and particulate concentrations of silver in Tokyo Bay estuarine waters and Japanese rivers were determined in this
study. The dissolved silver concentrations in the surface water of Tokyo Bay range from 5.9 to 15.1 pmol kg−1, which is comparable to those in the surface water of the Japan Sea, but two or three times higher than those in the surface
water of the open ocean. However, elevated concentrations of dissolved silver are not found in Tokyo Bay compared with those
in other highly urbanized estuaries, such as San Francisco Bay (20∼243 pmol kg−1). In the Tokyo Bay estuary, silver typically exhibits non-conservative mixing behavior, which is a common feature in the
other estuaries reported previously. Dissolved silver concentrations decrease with salinity from the rivers to the mouth of
Tokyo Bay. Silver is efficiently scavenged by suspended particulates, as evidenced by the high conditional distribution coefficients
for silver throughout the estuary (log Kd > 5.0 ± 0.6). The silver fluxes into Tokyo Bay via inflowing rivers and atmospheric deposition were estimated as 83 kg y−1 and 15 kg y−1, respectively. A simple budget calculation shows that the silver supplied from rivers and atmosphere must be rapidly scavenged
within the Tokyo Bay estuary. 相似文献
856.
溶藻弧菌asp基因在大肠杆菌中表达活性研究及条件优化 总被引:1,自引:0,他引:1
为进一步研究溶藻弧菌碱性丝氨酸蛋白酶(ASP)蛋白生物学活性和功能,将构建的pET23d-asp在大肠杆菌BL21(DE3)中表达,对表达产物进行纯化分析,并优化表达条件。结果表明:在咪唑洗脱缓冲液浓度为100 mmol/L时,表达的可溶性ASP被大量洗脱,纯化的ASP相对分子质量约为42 000,具有蛋白活性;在诱导温度28℃、异丙基-β-D硫代半乳糖苷(Isopropyl-β-D-thiogalactopyranoside,IPTG)浓度1 mmol/L及诱导时间16 h时,表达的活性ASP蛋白最多。 相似文献
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