几种氢氧化铁对亚砷酸根的吸附及预处理方法的影响   总被引：1，自引：0，他引：1  

叶瑛  季珊珊  邬黛黛  李俊  张维睿 《地质学报》2006,80(4):528

笔者研究了3种铁氧化物(氢氧化物)对亚砷酸根阴离子的吸附作用。三种吸附剂分别是Fe(OH)3凝胶,其真空微波干燥和80℃常规干燥产物。实验结果表明,将氢氧化铁凝胶与亚砷酸钠溶液混合后,六分钟内溶液的pH值从9.71升高至10.36,说明亚砷酸根取代了氢氧化铁中的氢氧根。反应40分钟后,pH值下降,原因很可能是被吸附的亚砷酸根表面络合体从单齿络合转变成为单核—双齿络合体并释放质子。pH值降低并不意味着吸附作用的结束,而是表明了反应类型的转变。温度和溶解空气对这两种反应的影响很小。将吸附剂超声波处理后,亚砷酸根的吸附总量增加了,不过…  相似文献   

Selected aspects of studies of sediments from the Ebro River （Spain） and the Dobczyce drinking water reservoir （Poland） within the frames of the European and national research projects     

Janusz Golas Jerzy Gorecki Mariusz Macherzynski Witold Reczynski Agnieszka Iwanicha Michal Sliwa 《中国地球化学学报》2006,25(B08):191-191

Mineral and organic matter either soluble or suspended are transported by the rivers and when deposited in the bed of the river or in the water reservoir, sediments are formed, whose chemical composition may serve as a fingerprint of the history of the ecosystem. The results of the studies of sediments in water systems （river catchments, reservoirs） can be used not only for the evaluation of the current state of the ecosystem but also to prevent any dangerous environmental changes. Bottom sediments can in many ways accumulate both suspended and soluble components. The process is influenced by several factors like pH, red-ox potential, oxygen content, interactions, etc. The complexity of those phenomena causes that in order to study the accumulation processes of compounds in sediments the application of various analytical techniques is required. The authors participate in two big projects on sediment studies. The AquaTerra Project is the EU funded project on understanding river-sediment-soil-groundwater interactions for support of management of river basins and catchment areas. Our group＇s studies are focused on mercury determination and its speciation in sediments and fish from the Ebro River in Spain. The Dobczyce Project is the national project funded by the Ministry of Education and sciences of Poland which is also a EU member country. The latter covers many aspects of accumulation and fate processes of chemical compounds in sediments of the reservoir which supplies 60% of drinking water to about one million population in the city of Krakow in Poland.  相似文献   

干燥脱水过程中纤维加筋固化淤泥的强度特性     

王玥  唐朝生  吕超  王鹏  荣德政  王宏胜 《地球科学进展》2019,(4):433-438

淤泥是一种天然含水率高且力学性质极差的固体废弃物,采取有效的技术方法进行快速脱水和增强可以实现淤泥资源化和高效利用。选取离散短丝聚丙烯纤维作为加筋材料,水泥和粉煤灰作为固化材料,通过开展无侧限抗压试验,研究了纤维加筋固化淤泥在干燥路径中强度的变化,并分析了干燥过程中不同目标含水率状态(分别为45%,40%,35%,30%,25%,20%,15%,10%和5%)和纤维掺量(0~0.8%)对加筋固化淤泥强度的影响机理。结果表明:①纤维的加入能有效提高固化淤泥的峰值强度和残余强度,且强度值随纤维掺量的增加呈现先上升后下降的趋势,最优纤维掺量为0.1%;②干燥脱水过程中,试样的无侧限抗压强度随含水率的减小近似于线性增加,破坏形式由塑性破坏逐渐向脆性破坏过渡,而纤维的加入可以有效抑制试样的脆性破坏,提升试样的韧性;③纤维加筋对固化淤泥强度的贡献随含水率的减小而逐渐增加,根本原因是纤维—淤泥界面作用力在低含水率条件下能得到更佳的激发。  相似文献   

Observed dryness and wetness variability in Shanghai during 1873–2005     

Zengxin Zhang  Qiang Zhang  Jinchi Zhang  Lanjun Zou  Jianmin Jiang 《地理学报(英文版)》2009,19(2):143-152

Dryness and wetness variations on different time scales in Shanghai were analyzed using the Standardized Precipitation Index (SPI) based on monthly precipitation data for 1873–2005. The SPI on scales of 3, 6, 12 and 24 months has been calculated. The SPI on 3, 6, 12 and 24 months present 4 wet periods prevailed during 1873–1885, 1904–1923, 1938–1960 and 1983–2005, and 3 dry episodes during 1886–1903, 1924–1937 and 1961–1982. Significant periods of higher wavelet power in the SPI-24 months occurred on the time scales of 2–7-year band in around 1880–1890, 1910–1950 and 1970–1990, and at 8–15-year band in 1920–1960 and 1965–2000 respectively. Periodicities in the SOI and ENSO indices are similar to those in SPI-24 months with little difference, namely, in the SPI-24 months, there are significant periods at the 2–7- and 8–15-year bands during 1930–1940. The periodicity components in individual SPI-24 months, SOI and ENSO indices are more complicated, showing the wetness and dryness variability in Shanghai is controlled by more than one physical factors. The research results indicate that the Shanghai area has experienced dryness and wetness variability on different time scales during the past 133 years. Foundation: Frontier Project of Nanjing Institute of Geography and Limnology, CAS, No.CXNIGLAS200814; National Forestry Science and Technique Foundation during the 11th Five-Year Plan Period, No.2006BAD03A1601; Project of Huaihe River Basin, No.HRM200708; National Climate Center, China Meteorological Administration, No.CCSF2007-35 Author: Zhang Zengxin (1977–), Ph.D, specialized in climatic changes.  相似文献   

1873-2005年上海干湿变化     

张增信  张强  张金池  邹兰军  江剑民 《地理学报(英文版)》2009,19(2)

Dryness and wetness variations on different time scales in Shanghai were analyzed using the Standardized Precipitation Index (SPI) based on monthly precipitation data for 1873-2005. The SPI on scales of 3, 6, 12 and 24 months has been calculated. The SPI on 3, 6, 12 and 24 months present 4 wet periods prevailed during 1873-1885, 1904-1923, 1938-1960 and 1983-2005, and 3 dry episodes during 1888-1903, 1924-1937 and 1961-1982. Significant periods of higher wavelet power in the SPI-24 months occurred on the time scales of 2-7-year band in around 1880-1890, 1910-1950 and 1970-1990, and at 8-15-year band in 1920-1960 and 1965-2000 respectively. Periodicities in the SOI and ENSO indices are similar to those in SPI-24 months with little difference, namely, in the SPI-24 months, there are significant periods at the 2-7- and 8-15-year bands during 1930-1940. The periodicity components in individual SPI-24 months, SOI and ENSO indices are more complicated, showing the wetness and dryness variability in Shanghai is controlled by more than one physical factors. The research results indicate that the Shanghai area has experienced dryness and wetness variability on different time scales during the past 133 years.  相似文献   

名贵中草药——牛膝     

《中国地名》2009,(2):57-57

牛膝为常用中草药,2000年版《中国药典》收载品种有牛膝和川牛膝。牛膝（怀牛膝）始载于《神农本草经》,历代本草均有记载,为苋科怀牛膝（栽培）的干燥根。川牛膝始见于唐代《理伤续断方》,20世纪60年代初,《四川中草孝勤才记载其来源为苋科川牛膝的干燥根。二者均有逐瘀通经,引血下行,补肝肾．强筋骨的功效。临床认为怀牛膝以补肝肾、强筋骨为长。川牛膝以通利关节、活血通经为长。除怀牛膝和川牛膝外,市售品尚有味牛膝、红牛膝、土牛膝、杜牛膝等多种。牛膝主要分为怀牛膝和川牛膝两种。  相似文献   

中国西北地区的干旱气候及水热资源的调节   总被引：2，自引：0，他引：2  

陈仲全  何友松  严江平 《中国沙漠》1984,4(4):33-40

本文用干燥度(K')和干燥率(D)表征西北干旱气候、干燥程度并进行了干旱气候区划,有助于了解西北干旱气候的的结构与分布。用月干燥度和湿润指数距平百分率(S%)分析年内干湿动态及干旱年变动的韵律性,有利于把握干旱动态的总趋势。为了合理利用西北干旱区水热资源,从调节水热资源的观点提出了计算合理蒸散(E_0.4)、合理灌溉深度(g_0.4)和合理灌溉定额(Q_0.4)的公式,并以西北干旱区为例作了计算与论证。  相似文献   

四逆散加减治疗干燥综合征验案1则          下载免费PDF全文

邓玉甲  周明爱 《应用海洋学学报》2019,35(8):83-84

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Analyses of dry intrusion and instability during heavy rainfall event occurred in Northern China          下载免费PDF全文

YANG Shuai  CUI Xiaopeng  RAN Lingkun 《大气和海洋科学快报》2009,2(2):108-112

The 1°×1° National Center for Environmental Prediction/National Center for Atmospheric Research （NCEP/NCAR） data and mesoscale numerical simulation data are analyzed to reveal a mechanism for the formation of heavy rainfall in Northern China; this mechanism is the non-uniformly saturated instability induced by a dry intrusion. The dry intrusion and the accompanying downward transport of air with a high value of potential vorticity （PV） are maintained during the precipitation event. As the dry air intrudes down into the warm and moist sector in the lower troposphere, the cold, dry air and the warm, moist air mix with each other, and, as a result, the atmosphere becomes non-uniformly saturated. On the basis of this non-uniform saturation, a new Brunt-Vaisaila frequency （BVF） formula is derived and applied to the precipitation event. It is shown that, compared to the conditions of either a dry or a saturated atmosphere, the BVF in a non-uniformly saturated, moist atmosphere （BVF） may be more appropriate for depicting the atmospheric instability in rainy regions.  相似文献   

勉略地区寒武纪含碳岩系稀土元素地球化学特征及成因意义     

乔耿彪  杨钟堂  李智明  杨晓勇  蓝翔华 《吉林大学学报(地球科学版)》2011,41(4):1067-1076

采用等离子质谱仪(ICP-MS)测试方法对岩石的稀土元素含量进行了测定,探讨了勉略地区寒武纪含碳岩系的稀土元素地球化学特征及其成因。研究表明:含碳岩系岩石的稀土元素总量(∑REE)总体变化不大,质量分数为(167.88~210.50)×10-6,平均为192.20×10-6;轻重稀土比值(LREE/HREE)为6.64~16.25,平均为11.52,显示轻稀土富集而重稀土亏损;含碳岩系岩石具明显的Ce负异常,δCeN值为0.58~0.90(平均为0.78),表明其主要形成于干燥气候条件下的缺氧还原沉积环境,且为近陆边缘海(即浅海)沉积位置;本区含碳岩系岩石具明显的Eu负异常,δEuN值为0.47~0.83(平均为0.62),说明其形成于被动大陆边缘,为低温成岩作用(<250℃)下的正常海水及其沉积物;含碳岩系岩石的La/Yb-REE图解及La/Yb-Ce/La图解也表明其非热水沉积特征,为正常的海洋沉积环境,其物质可能主要来自正常海相沉积环境下较高石英含量的陆壳。  相似文献