281 resultados para 6 methoxyluteolin 7 o beta dextro allopyranoside
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由于茶树种植,茶园土壤pH略低于茶园外土壤;交换性铝、水溶性氟、交换性氟、有机结合态铝和土壤pH之间显著负相关。茶树体内氟、铝分布表现出很好的一致性。老叶、嫩叶、落叶和茶果中Al/F比值基本保持恒定(2.6~2.7),说明氟和铝是以某种成分固定的化合物形态存在并随叶片的生长而累积。在茶树生长适宜的土壤pH范围内,适当提高土壤的pH值,就可能使土壤中可利用的氟、铝大为降低,从而减少茶树中氟、铝的富集。测定茶叶水溶性氟最佳条件是:1.0g茶叶加250ml 70℃沸过去离子水,浸泡40min后,取样,加入TISAB(Na3Cit 294.0g,KNO3 20.0g/L,pH 6.0),氟离子选择性电极法测定。
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阿哈水库是贵阳市集中式生活饮用水源地一级保护区,具有极为重要的社会和经济功能。长久以来阿哈水库流域内乡镇煤矿、个体煤窑矿采严重,大量酸性矿山废水未经处理直接入库以及近几年来的人工石灰投放使阿哈水库水体成为罕见的高铁锰含量的硫酸盐型水体。本研究于同一水文年的枯水期(2005年3月)和丰水期(2005年8月)分别对水库不同深度分层水体、沉积物间隙水、沉积柱剖面、阿哈水库所有支流水体中不同形态汞的含量、分布特征以及迁移转化规律进行了详细的研究。研究结果发现: 1. 阿哈水库水体中各种形态汞浓度均出现季节性变化。总汞(HgT)浓度变化范围为2.1~19.5 ng̶6;L-1,平均为9.3ng̶6;L-1;溶解态汞(HgD)浓度变化范围为1.7~ 9.0 ng̶6;L-1,平均为4.1ng̶6;L-1;颗粒态汞(HgP)浓度范围为0.3~14.8 ng̶6;L-1,平均5.2 ng̶6;L-1;活性汞(HgR)浓度范围为0.1~ 4.5 ng̶6;L-1,平均1.7 ng̶6;L-1; 2. 阿哈水库水体颗粒态汞与总汞呈极显著相关,说明阿哈水库水体的颗粒态汞强烈影响着总汞迁移和分布。水库水体甲基汞与溶解态汞之间存在极显著正线性相关,证明水库水体中的甲基汞的产生和迁移与溶解态汞有着密切的关系,但是,水体甲基汞与总汞之间并不存在相关性。 3.阿哈水库水体丰水期溶解态汞、活性汞、溶解态甲基汞浓度均远高于枯水期浓度,除了外源径流输入的影响外,很大程度与丰水期水库底部缺氧,氧化还原界面由沉积物-水界面进入水体密不可分。较大表面积铁锰氧化物还原为可溶态的铁锰离子,使沉积物释放大量被吸附的汞进入水体,造成水体溶解态汞、活性汞、溶解态甲基汞的升高。 4. 阿哈水库沉积物间隙水中总汞和甲基汞浓度出现明显的季节性变化,丰水期〉枯水期。间隙水中甲基汞浓度与沉积物中甲基汞含量呈极显著性相关。阿哈水库沉积物间隙水中甲基汞的浓度除了沉积物表层0cm到表层下8cm出现峰值外,在表层10cm以下仍然发现有浓度波动,两者可能归因于汞的甲基化进程受硫酸盐还原菌和铁还原菌的双重影响。 5. 阿哈水库沉积物总汞含量在枯水期和丰水期基本没有变化,变化范围为160-252 ng̶6;g-1,平均为209 ng̶6;g-1,大大高于其他未受污染地区水库沉积物中总汞含量。甲基汞含量变化范围为0.22-7.21 ng̶6;g-1,平均为1.76 ng̶6;g-1。 6. 阿哈水库入库河流pH为7.5-8.5,总汞浓度为7.1-47.9 ng̶6;L-1;甲基汞浓度为0.16-2.50 ng̶6;L-1;活性汞浓度为0.25-2.43ng̶6;L-1,且随季节变化明显,枯水期<丰水期。阿哈水库入库河流汞的主要存在形态为颗粒态汞,总汞与颗粒态汞呈显著正相关。九十年代末期至今,矿山煤窑废水经集中治理,阿哈水库流域的煤窑废水污染状况得到很大改善。目前,阿哈水库汞的主要来源为未经处理直接排入水库中的生活污水和其它工业废水。阿哈水库唯一的出湖河流-小车河中,各种形态的汞均较入湖河流中的汞含量大大减少,这表明水库的沉淀和拦截净化作用相当显著。
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贵州位于世界上连片分布面积最大的中国西南岩溶区的中心,近年来石漠化问题突出,且有不断恶化的趋势,给当地经济发展和人类生存带来了极大障碍。对石漠化的成因机理进行研究,是石漠化治理的前提和理论依据。但目前对石漠化的研究基本以定性分析为主,定量化不足。没有统一的石漠化等级划分标准, 对于石漠化过程土壤、植物的退化本质也不是很清楚,这给石漠化治理带来了极大的障碍。 本文通过在小流域尺度上,以贵州花江峡谷查耳岩小流域为研究区域,对喀斯特石漠化过程土壤、植被退化进行定量分析,以确定土壤-植被系统营养元素协变关系,分析了石漠化演替过程中土壤、植被的变化,土壤、植被间关联退化的关系。还检验了景观上石漠化划分方法是否能体现出退化的本质。取得了以下几点认识: (1) 在研究区土壤pH值在6.9-7.8的中性偏碱性范围,土壤总钙、交换态钙含量高,氮含量丰富,有机质、养分全量较高,有效态含量除了速效K、P在部分样地含量较低外,其它营养元素的有效态养分含量都较高。 (2) 在喀斯特石漠化地区植物灰分含量高,富钙、氮,相对缺铁、锌、钾、磷,植物灰分含量与植物钙含量成显著正相关,即随着植物钙含量的增加植物灰分含量增加。 (3) 通过对四套石漠化序列比较得出,在弃耕地两套石漠化序列中,土壤为棕色石灰岩土,土层较厚,土壤覆盖度、总量相对较高,但是有机质、有效态养分含量相对低,随着演替土壤质量有下降趋势,但是没有明显规律。樵采的两套石漠化序列,土壤为发育较年轻的黑色石灰土,土层很薄,土壤覆盖度低,总量少,零星分布在负地形中,但是土壤有机质、全量养分、速效养分含量都较丰富,随着石漠化演替没有呈现相应的规律变化。 (4) 按照目前景观上石漠化的划分标准,在土壤退化上,没有表现出随石漠化演替土壤质量发生规律退化。这主要由于喀斯特山地的特殊性,在石灰土地区土壤厚度差异很大,分布零星,在土壤很薄的地方只要发生轻微的水土流失可能会出现强度石漠化的景观,而在土壤相对厚的地方要经过较强的水土流失才会出现石漠化景观。尽管开垦和樵采两种不同的人为干扰方式下产生的石漠化景观可能很相似,但是在土壤退化程度上不一致,而景观划分标准不能区分这两种情况,导致了土壤并没有表现出随石漠化演替出现规律退化。要将土壤退化这一本质内容涉及到石漠化等级划分中,应将土壤质量评价方面的因子及其量化标准补充到石漠化划分标准中。 (5) 研究区植被在结构上与石漠化的演替形成很好对应关系,随着石漠化的演替,植被从乔-草灌-灌草-稀疏灌草演化,但是植物营养元素、灰分没有随着石漠化的演替而发生规律变化,表明在景观上的划分标准体现了植被宏观的变化,但是对于植物营养元素、灰分含量的微观变化没有呈现出相应的变化规律。 (6) 土壤元素有效态含量与土壤pH值、机械组成的相关性弱或者不相关,与养分全量、有机质的相关性较强。 (7)石漠化过程中,土壤——植物系统表现出复杂的关系。土壤各项物理性质及元素的全量、有效态含量与植物灰分、元素含量的相关性很弱或者基本不相关,随着石漠化的演替土壤——植物系统营养元素也没有表现出规律变化。
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新疆阿尔泰南缘泥盆纪的构造背景一直存在争论。而且,该地区系统的地球化学工作还很薄弱。对阿尔泰南缘克朗和麦兹盆地内的斜长角闪岩和变流纹岩进行的系统的岩石学和地球化学研究,为阿尔泰南缘泥盆纪的构造背景和地壳演化提供了重要证据。获得的主要结论有: (1)斜长角闪岩的原岩为拉斑玄武岩。克朗盆地样品相对于N-MORB表现为“隆起型”曲线形式,而麦兹盆地样品相对于N-MORB表现为富集大离子亲石元素和轻稀土元素,而亏损高场强元素。另外,克朗盆地样品具有较高的εNd(t)值(+6.4~+7.4),而麦兹盆地样品则具有偏低的、较宽泛的εNd(t)值(+1.7~+7.3)。地球化学和Nd同位素组成表明,麦兹盆地部分样品可能受到了不同程度的陆壳物质混染。克朗盆地地幔源区表现为亏损上地幔和富集地幔组分的相互作用,而麦兹盆地的地幔源区为受俯冲板片流体/熔体交代的地幔楔。研究表明斜长角闪岩的原岩可能形成于具有陆壳基底的岛弧/弧后盆地环境。 (2)克朗和麦兹盆地的变流纹岩具有高SiO2、较高(Na2O+K2O)、低TiO2和CaO含量,属于亚碱性系列。稀土元素配分模式表现为富集轻稀土元素、Eu负异常强烈。变流纹岩的微量元素蛛网图曲线形式类似于智利岛弧花岗岩。在相关判别图上,它们落入火山弧花岗岩区。变流纹岩的εNd(t)值为-2.9~+1.3,它们的两阶段Nd模式年龄(TDM2)为1.04~1.38Ga。其成因与中元古地壳熔融有关,同时有一定量年轻地壳物质的参与。这些结果显示,变流纹岩形成于发育俯冲带的陆缘火山弧环境。 (3)根据本次研究结果并综合区域地质资料和前人研究成果,提出了阿尔泰南缘泥盆纪的构造岩浆模式。
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贵州省是我国最重要的汞工业基地,境内分布着大量的汞矿床,汞金属储量88000 t,占全国总储量近80%。汞矿开采、冶炼历史悠久,大规模的汞矿开采冶炼活动都已经停止。但是,由于汞矿区偏僻的自然地理位置、落后的经济水平和近期金属汞价格的攀升,这些地区仍然存在着较大规模的土法炼汞活动。大面积的土法炼汞活动和长期的大规模汞矿开采冶炼活动,给矿区生态环境造成了严重的汞污染。土法炼汞工艺十分落后,冶炼过程向周围大气释放大量的汞,而土法炼汞工人也必然会遭受严重的汞蒸气暴露。释放到大气的汞在进入周围环境后,在自然条件下通过微生物活动,会转化为毒性、生物有效性更强的甲基汞,并通过食物链富集放大,最终对矿区居民的身体健康构成一定的威胁。 本文选择贵州省务川汞矿区、万山汞矿区和铜仁垢溪、老屋场土法炼汞地区,进行了土法炼汞的汞释放量估算、汞矿地区环境汞污染调查及炼汞工人和矿区居民汞暴露调查和健康风险评价,系统阐述了贵州典型土法炼汞地区汞的生物地球化学循环特征及人体汞暴露评价。 1. 务川和铜仁垢溪地区的土法炼汞活动是当地大气的最主要人为释汞源。务川汞矿区土法炼汞的平均释汞因子为18.2%(6.9-32.1%),土法炼汞活动每年向大气排汞3.7-9.6 t;铜仁垢溪地区土法炼汞的平均释汞因子为9.8%(6.6-14.5%),土法炼汞活动每年向大气排汞1.3-2.7 t。 2. 务川汞矿区大面积的土法炼汞活动和长期大规模的汞矿活动以及垢溪、老屋场地区的土法炼汞活动,给当地的大气、地表水体和土壤造成了严重的汞污染,而汞污染程度受汞矿开采冶炼活动的历史和规模的影响显著。务川汞矿区大气汞浓度空间变化很大(7-40000 ng̶6;m-3),受矿业活动影响的区域,大气汞含量明显升高;重污染区大气汞平均浓度为15000 ng̶6;m-3,轻污染区为120 ng̶6;m-3,对照区为24 ng̶6;m-3。务川矿区地表水体的总汞含量的变化范围为43-2100 ng̶6;L-1,总甲基汞含量变化范围为0.30-1.1 ng̶6;L-1;垢溪、老屋场地区地表水体总汞含量的变化范围为92-2300 ng̶6;L-1,总甲基汞含量变化范围为2.6-7.9 ng̶6;L-1,地表水体显示了极强的甲基化能力。颗粒态汞占地表水体总汞含量的绝大部分比例,是矿区地表水体汞迁移的主要方式;而甲基汞则以溶解态为主。务川汞矿区土壤总汞含量的变化范围为1.3-360 mg̶6;kg-1,垢溪、老屋场地区土壤总汞含量的变化范围为0.18-47.5 mg̶6;kg-1,土壤剖面表层土壤汞的富集表明大气汞的沉降是土壤汞的重要来源,而土壤pH、有机质含量和土地利用类型影响着土壤中汞的迁移和富集。 3. 务川汞矿区土法炼汞工人尿汞含量的平均值高达1060 61549;g̶6;g-1 Cr,铜仁垢溪地区炼汞工人尿汞含量的平均值为347 61549;g̶6;g-1 Cr,铜仁老屋场地区炼汞工人尿汞含量的平均值为917 61549;g̶6;g-1 Cr,土法炼汞工人尿汞平均含量远远超过世界卫生组织规定的职业暴露人群的最大允许值-50 61549;g̶6;g-1 Cr,说明土法炼汞工人遭受严重的汞蒸气暴露。部分土法炼汞工人已经表现出轻度慢性汞中毒的症状,其肾脏已经遭受到一定程度的损伤。铜仁垢溪地区一般居民尿汞的平均值为40.0 61549;g̶6;g-1 Cr,铜仁老屋场地区一般居民尿汞含量的平均值为66.2 61549;g̶6;g-1 Cr,万山汞矿区大水溪居民尿汞含量的平均值为56.9 61549;g̶6;g-1 Cr,说明土法炼汞地区一般居民也遭受一定的汞蒸气暴露。对照区人群尿汞含量的平均值为1.30 61549;g̶6;g-1 Cr,万山下场溪村居民尿汞含量的平均值为2.5 61549;g̶6;g-1 Cr,其尿汞水平与对照组接近。 4. 食用大米是汞矿区居民甲基汞暴露的主要途径。万山汞矿区大水溪、下场溪和报溪3个村庄居民头发总汞含量的几何平均值分别为7.3、1.9和2.3 61549;g̶6;g-1,而头发甲基汞的平均含量分别为2.8、1.3和1.5 61549;g̶6;g-1,说明万山汞矿区居民存在一定程度的汞暴露。3个村庄居民食用大米总汞的平均含量分别为58.5、21.3和33.1 ng̶6;g-1,大米甲基汞的平均含量分别为14.6、5.7和4.0 ng̶6;g-1。居民食用的蔬菜、猪肉和饮水也表现出很高的总汞含量,但是甲基汞含量很低。3个村庄居民食用大米的摄入量占总甲基汞摄入量的平均比例分别为97.5%、94.1%和93.5%,且不同参与者每日通过食用大米的甲基汞摄入量和对应的头发甲基汞含量之间存在显著的相关关系 (r=0.65, p<0.01),这证实了居民头发甲基汞的来源确实是食用大米,食用大米是汞矿区居民甲基汞暴露的主要途径。 5. 铜仁垢溪、老屋场地区炼汞工人头发甲基汞的平均含量分别为5.05 61549;g̶6;g-1(2.35-10.6 61549;g̶6;g-1)和5.63 61549;g̶6;g-1(2.54-9.55 61549;g̶6;g-1),而一般居民头发甲基汞的平均含量分别为3.53 61549;g̶6;g-1(1.87-5.65 61549;g̶6;g-1)和4.01 61549;g̶6;g-1(2.29-9.23 61549;g̶6;g-1)。万山汞矿区大水溪、下场溪和报溪3个村庄居民头发甲基汞的平均含量分别为2.8、1.3和1.5 61549;g̶6;g-1。务川汞矿区土法炼汞工人和居民的头发甲基汞含量的变化范围为0.47-5.69 μg̶6;g-1。对照组头发甲基汞的平均含量为0.65 61549;g̶6;g-1,变化范围为0.26¬-1.38 61549;g̶6;g-1。食用大米甲基汞摄入量的估算表明,铜仁垢溪和老屋场地区部分居民的甲基汞摄入量已经超过世界卫生组织2003年制定的标准-0.23 61549;g̶6;d-1̶6;kg-1,汞矿区大部分人群的甲基汞摄入量超过了美国环保局的推荐值-0.1 61549;g̶6;d-1̶6;kg-1 (USEPA, 1997),而对照区居民的甲基汞摄入量均没有超过这一推荐值,表明铜仁垢溪和老屋场地区居民存在一定的甲基汞暴露风险,而其他汞矿区人群也存在通过食用大米暴露甲基汞的潜在风险。
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丰富的铅锌矿资源为我国经济社会的发展作出了重要贡献,但也不可避免带来严重的环境污染,特别是酸性矿山废水及重金属污染已成为当今世界面临的两大环境难题。最让人们不安的是,即使在矿山关闭数十年、数百年,甚至更长时间,矿山尾矿等浸出液对矿区生态环境的影响依然存在。闪锌矿是铅锌矿中主要矿物之一,也是镉的主要载体矿物,而镉是有毒重金属元素,其毒性仅次于汞。大量含硫化物废石、尾矿暴露于地表环境,发生水-岩-气之间的反应(即氧化淋滤作用)产生酸性矿山废水和释放大量Zn、Cd等重金属元素,进入矿区水体、土壤,影响甚至破坏矿区生态环境,危害人类健康。通过表生环境条件下矿石风化淋滤实验和闪锌矿氧化动力学实验研究,认识铅锌矿石及闪锌矿氧化淋滤过程、速率及其影响因素,揭示Zn、Cd等重金属元素的释放、迁移及富集规律,并建立定量模型,为正确预测、评价和控制铅锌矿山的环境污染提供科学依据。 本文以牛角塘富镉锌矿床为研究对象,主要通过闪锌矿氧化动力学实验、矿石风化淋滤实验及矿区环境调查将闪锌矿氧化-矿石风化淋滤-环境污染有机地联系在一起,主要取得以下几点认识: 1、矿石风化淋滤实验表明,牛角塘铅锌矿石淋滤后淋滤液主要呈碱性,淋滤释放出大量Zn2+、Cd2+、Ca2+、Mg2+等阳离子及SO42-、CO32-等阴离子,淋滤过程中形成大量以石膏为主要成分的沉淀物,淋滤液中Zn、Cd主要以沉淀形式存在(可能被沉淀吸附或包裹),而水溶态Zn、Cd浓度极低。 2、牛角塘矿床中黄铁矿锌矿石中Zn和Cd淋滤率较半氧化锌矿石低得多,表明半氧化或氧化锌矿石的风化淋滤作用更强烈。 3、在Fe2(SO4)3为氧化剂时,闪锌矿氧化速率随着Fe3+浓度的增加、温度升高、pH值降低而增加,且闪锌矿氧化过程中Zn、Cd的释放速率大致相同;在有限实验时间内(本文中小于60h)黄铁矿的混入对闪锌矿氧化速率起抑制作用,可能是黄铁矿与闪锌矿与Fe3+反应过程中存在竞争关系;反应的活化能分别为Ea(Zn)41.75 kJ.mol-1、Ea(Cd)42.51 kJ.mol-1,说明闪锌矿氧化速率受矿物表面反应控制。氧气氧化闪锌矿时,随着pH值的变化闪锌矿的氧化机理发生变化,在2<pH≤6范围内,闪锌矿氧化速率随着pH值的增加而降低,而在6<pH≤7.8范围内,随着pH值增加,闪锌矿氧化速率反而增加。Fe3+和氧气均对闪锌矿的氧化起重要作用,但以Fe3+氧化为主。 4、大多数闪锌矿氧化实验中Zn、Cd的溶解曲线非常相似、活化能相近,表明Zn和Cd存在相似的地球化学行为。但在闪锌矿溶解过程中Zn、Cd的释放速率存在差异,在酸性介质条件下Cd的释放速率比Zn略快,而中碱性介质条件,Cd的释放速率比Zn慢。这与Zn、Cd同处元素周期表第ⅡB族,它们之间既存在许多相似的地球化学性质,也存在不少差异有关。 5、利用双对数图法处理实验数据,得出表生环境条件下闪锌矿氧化速率公式为: 或 该公式可用于估算一定时间内闪锌矿氧化所释放的Zn、Cd等重金属元素的总量,为正确预测、评价和控制铅锌矿山的环境影响提供科学依据。 6、牛角塘矿区环境调查结果表明,牛角塘矿山水体主要呈中碱性,水体污染较轻,大多水体中Zn、Cd含量未超过农业灌溉标准及饮用水国家标准,这主要受矿区碳酸盐岩地层的影响。但矿区土壤、河流沉积物及植物中Zn、Cd均超过相关国家标准,遭到不同程度污染。 7、本文研究表明,闪锌矿氧化及铅锌矿风化淋滤过程中,将产生矿山酸性废水和释放Zn、Cd等重金属元素,污染矿区及其下游生态环境,危害人类健康。我们可以采取以下措施进行防范和控制环境污染:第一,提高矿区水体pH值,降低闪锌矿等硫化物矿物氧化速率;第二,尽量减少废石、尾矿直接暴露于空气、Fe3+等氧化剂环境中,如可在废石(渣)、尾矿表面盖上覆土等,也可降低闪锌矿等硫化物矿物的氧化速率。
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中国西南喀斯特地区有突出的地球化学敏感性和生态环境脆弱性等特征,其中水环境污染是喀斯特地区所面临的极其严重的生态与环境问题。水环境生源物质循环过程对于人类生存环境质量的保护和提高有着直接的联系,由于环境体系受多种控制因素影响,利用多同位素方法讨论单一环境体系中物质循环过程和生态环境效应已成为同位素地球化学发展的一个重要趋势。碳、氮同位素已被广泛用于探讨和解决当前的一些重大环境问题,如生源要素生物地球化学对人为污染物的响应、温室气体的来源、湖泊富营养化、地下水硝酸盐污染等。为此本论文利用稳定同位素技术(13C、I5N、18O),以喀斯特城市地下水为主要研究对象,对贵阳雨水中的C、N沉降过程、贵阳/遵义地下水C、N同位素地球化学进行了初步研究。通过以上研究,得到以下的主要认识。1.探讨了贵阳雨水中碳沉降的年变化特征,结果表明贵阳雨水DOC平均值为3.76mg/L,POc平均值为0.54mg/L,含量季节间变化不显著。雨水中DOc与PH呈负相关关系,表明有机碳中酸性成份对酸雨有一定贡献。δ13C-POC取值范围在(-27.0,-24.0‰)之间,季节间差异不大,结合已有研究结果表明雨水中颗粒有机碳主要来源于雨水所冲刷的本地大气颗粒物。2.探讨了贵阳雨水无机氮沉降的年变化特征,结果表明贵阳城区雨水中的NH4+、NO3-、δ15N-NH4+,δ15N-NO3-,δ18O-NO3-,季节性差别都不大。NH4+主要来源于土壤中NH3挥发以及大气颗粒物中按的洗脱,而硝酸盐可能主要来源于燃煤和机动车的排放等,同时气候是影响同位素组成差异性表现的一个重要影响因素。3.初步分析了贵阳与遵义地下水/地表水主要水化学成分,结果证实水体水化学组成主要受研究区水文地质背景控制,即阳离子主要以Ca2+,Mg2+为主,而阴离子以HCO3-,SO42-离子为主。但是有部分水样有较高的人为输入物质K+,Na+,Cl-和NO3-,表明人为活动在研究区内已对地表水/地下水产生一定影响。4.利用碳同位素较好地示踪了地下水溶解无机碳季节变化的主要规律,地下水夏季的DIC含量明显低于冬季DIC含量,这是由于大量降水的稀释作用引起的。地下水DIC夏季一般比冬季更富集12C,表明夏季地下水中生物成因无机碳贡献增加。经计算表明贵阳/遵义地下水来源于碳酸盐风化的无机碳比重大多数大于50%,表明硫酸可能参与风化过程。5.较为系统地探讨了地下水/地表水中有机碳的冬季/夏季演化规律以及受影响因素,地下水大多数样品DOC和POC含量不高,个别受污染样品明显具有较高有机碳含量。大部分夏季地下水δ13C-POC明显大于冬季,表明夏季地下水颗粒有机碳受外源(C4植物碎屑)输入影响。地表水TOC(DOC+POC)与人为输入离子[K+Na++Cl-]呈一定的正相关关系,表明有机碳主要受人为污染影响。6.以贵阳为例,根据δ13CDIC等势图、结合主要水化学特征在空间上的分布可知,贵阳市区中部,东北部及西郊农业区地下水受污染较为严重。表明一定条件下,碳同位素组成可以用来指示区域地下水受人为活动影响范围。7.通过对地下水三氮分析初步掌握了地下水氮污染的基本特征,地下水中NO3-是最主要的无机氮形态,NH4+和NO2-含量大多较低,地下水中具有高NO2-与NH4+的水样比较分散,表明点源污染是主要的。8.利用氮氧同位素示踪了贵阳地下水硝酸盐污染来源的季节变化,同时证实了部分地下水发生反硝化。冬季硝酸盐相对夏季含量较低,并且目SN与夕80的平均值都相对较高,表明夏季受外源氮污染明显,郊区地下水硝酸盐主要受硝态氮肥污染影响,城区地下水硝酸盐污染严重,城市生活排泄物是主要的氮污染源;硝酸盐氮氧同位素联同按氮同位素等可以得知部分地下水中存在明显的反硝化作用。9.利用氮同位素取值分布和季节间频度分布变化初步讨论了遵义地下水硝酸盐污染来源的季节变化。遵义含NO3-较高的地下水主要分布在市区、茅草铺(市东北郊)和新店子一忠庄一带(市东南郊)。夏季地下水硝酸盐δ15N的平均值明显低于冬季,一表明夏季地下水受农业化肥等低δ15N值氮污染源污染。10.两城区地下水受点源污染为主,在局部区域有向含水层面源污染转化的趋势。喀斯特城区地下水中C、N物质的循环对环境变化响应较快,同时受不同区域降雨过程和土壤营养物质过程影响而表现出一定的差异性。
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Orthogonal design and uniform design were used for the optimization of separation of enantiomers using 2,6-di-O-methyl-beta-cyclodextrin (DM-beta-CD) as a chiral selector by capillary zone electrophoresis, The concentration of DM-beta-CD, buffer pH, running voltage, and capillary temperature were selected as variable parameters, their different effects on peak resolution were studied by the design methods. It was concluded that orthogonal design offers a rapid and efficient means for testing the importance of individual parameters and for determining the optimum operating conditions. However, for a large number of both factors and levels, uniform design is more efficient, The effect of addition of methanol and citric acid buffer on the separation of enantiomers was also examined.
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To explore the presence of depression, anxiety and cardiac events after coronary artery bypass grafting (CABG) prospectively and comparably. To analysis influential factors of depression and anxiety ( peri-operation and 1 year after operation ), and the effection on cardiac events in the year after operation. We followed the patients who underwent scheduled consecutive CABG. We interviewed patients to assess depression, anxiety symptoms using self-rating depression scale( SDS) and self-rating anxiety scale(SAS)before operation , before discharge and 1 year after operation. And cardiac events were also identified. All patients were divided into the group with depression and/or anxiety symptoms or the other group without depression and/or anxiety symptoms 3 times according to depression and anxiety symptoms before operation , before discharge and 1 year after operation. 69 patients completed the follow-up.24 patients (34.8%) had depression and/or anxiety symptoms before CABG, 31 patients (44.9%) had depression and/or anxiety symptoms before discharge, and 10 patients (14.5%) had depression and/or anxiety symptoms 1 year after operation. 6 patients(8.7%) had cardiac events, and 5 patients were re-admitted. Arhythmia before and after operation, the quantity of blood vessel grafted, length of stay , depression and anxiety symptoms before operation, cardiac events may lead to depression and anxiety symptoms 1 year after operation. The use of cardiopulmonary bypass grafting (CPB), Arhythmia after operation, the prolonged length of stay are influential factors of cardiac events. Though the incidence of depression and/or anxiety symptoms 1 year after operation is lower than before operation and before discharge, it is high still. Arhythmia before and after operation, the more blood vessels grafted, the prolonged length of stay , depression and anxiety symptoms before operation and cardiac events could be risk factors of depression and anxiety symptoms 1 year after operation. Much attention must be paid to this phenomenon. Heavy patient's condition, complicated surgery are risk factors of cardiac events, and bad emotion before operation and before discharge are independent to cardiac events. Key words: perspective research; depression;anxiety; coronary artery bypass grafting; follow up
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This study is aimed at examining the degree of the basic scales (validity scales and clinical scales) between The Chinese MMPI and MMPI-2. Four samples (include schizophrenia, affective disorder, neuroses and normal subjects) of 236 subjects completed MMPI/MMPI-2 Combined Questionnaires in groups. The concordance rate for total code types was 90.1%. For 1-point, 2-point, 3-point and elevated code types, they were separately 81.6%, 65.8%, 49.2%, 64%. Only 56.8% of men compared to 73.8% of the women showed concordance in 2-ponit code types between MMPI and MMPI-2. And 58% of normal subjects compared to 48% of the schizophrenia subjects showed concordance in 3-point code types. Of the 236 cases, 156 (66.1%) had code types that were "well-defined" (1-, 2- or 3-point). 1-point, 2-point, 3-point well-defined code types respectively were 38.6%, 29.7%, 21.6%. For 2-point code types which were well-defined, the concordances was 84.3%, 82.8%, 85.7% (all the cases, men, women), higher than 64.4%, 56.8%, 72.9% when they were free-defined. 96.4% of subjects with incongruent 2-point code types had one of the scales in their MMPI code types with MMPI-2 code types. When deference caused by the use of uniform T-scores and new norms in MMPI-2 were found, the differences typically in code types congruence were not very great. Comparison of mean scores for the validity and clinical scales, 7 raw scores and 12 T-scores showed significant difference for MMPI versus MMPI-2 (Form). In spite of significant mean differences, correlational analyses show correlations above 0.92 for the raw scores and T-scores for each gender. All these results showed the good consistence between MMPI and MMPI-2 in basic scales, and showed MMPI-2 should be studied deeply.
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The time-courses of orthographic, phonological and semantic processing of Chinese characters were investigated systematically with multi-channel event-related potentials (ERPs). New evidences concerning whether phonology or semantics is processed first and whether phonology mediates semantic access were obtained, supporting and developing the new concept of repetition, overlapping, and alternating processing in Chinese character recognition. Statistic parameter mapping based on physiological double dissociation has been developed. Seven experiments were conducted: I) deciding which type of structure, left-right or non-left-right, the character displayed on the screen was; 2) deciding whether or not there was a vowel/a/in the pronunciation of the character; 3) deciding which classification, natural object or non-natural object, the character was; 4) deciding which color, red or green, the character was; 5) deciding which color, red or green, the non-character was; 6) fixing on the non-character; 7) fixing on the crosslet. The main results are: 1. N240 and P240:N240 and P240 localized at occipital and prefrontal respectively were found in experiments 1, 2, 3, and 4, but not in experiments 5, 6, or 7. The difference between the former 4 and the latter 3 experiments was only their stimuli: the former's were true Chinese characters while the latter's were non-characters or crosslet. Thus Chinese characters were related to these two components, which reflected unique processing of Chinese characters peaking at about 240 msec. 2. Basic visual feature analysis: In comparison with experiment 7 there was a common cognitive process in experiments 1, 2, 4, and 6 - basic visual feature analysis. The corresponding ERP amplitude increase in most sites started from about 60 msec. 3. Orthography: The ERP differences located at the main processing area of orthography (occipital) between experiments 1, 2, 3, 4 and experiment 5 started from about 130 msec. This was the category difference between Chinese characters and non-characters, which revealed that orthographic processing started from about 130 msec. The ERP differences between the experiments 1, 2, 3 and the experiment 4 occurred in 210-250, 230-240, and 190-250 msec respectively, suggesting orthography was processed again. These were the differences between language and non-language tasks, which revealed a higher level processing than that in the above mentioned 130 msec. All the phenomena imply that the orthographic processing does not finished in one time of processing; the second time of processing is not a simple repetition, but a higher level one. 4. Phonology: The ERPs of experiment 2 (phonological task) were significantly stronger than those of experiment 3 (semantic task) at the main processing areas of phonology (temporal and left prefrontal) starting from about 270 msec, which revealed phonologic processing. The ERP differences at left frontal between experiment 2 and experiment 1 (orthographic task) started from about 250 msec. When comparing phonological task with experiment 4 (character color decision), the ERP differences at left temporal and prefrontal started from about 220 msec. Thus phonological processing may start before 220 msec. 5. Semantic: The ERPs of experiment 3 (semantic task) were significantly stronger than those of experiment 2 (phonological task) at the main processing areas of semantics (parietal and occipital) starting from about 290 msec, which revealed semantic processing. The ERP differences at these areas between experiment 3 and experiment 4 (character color decision) started from about 270 msec. The ERP differences between experiment 3 and experiment 1 (orthographic task) started from about 260 msec. Thus semantic processing may start before 260 msec. 6. Overlapping of phonological and semantic processing: From about 270 to 350 msec, the ERPs of experiment 2 (phonological task) were significantly larger than those of experiment 3 (semantic task) at the main processing areas of phonology (temporal and left prefrontal); while from about 290-360 msec, the ERPs of experiment 3 were significantly larger than those of experiment 2 at the main processing areas of semantics (frontal, parietal, and occipital). Thus phonological processing may start earlier than semantic and their time-courses may alternate, which reveals parallel processing. 7. Semantic processing needs part phonology: When experiment 1 (orthographic task) served as baseline, the ERPs of experiment 2 and 3 (phonological and semantic tasks) significantly increased at the main processing areas of phonology (left temporal and frontal) starting from about 250 msec. The ERPs of experiment 3, besides, increased significantly at the main processing areas of semantics (parietal and frontal) starting from about 260 msec. When experiment 4 (character color decision) served as baseline, the ERPs of experiment 2 and 3 significantly increased at phonological areas (left temporal and frontal) starting from about 220 msec. The ERPs of experiment 3, similarly, increased significantly at semantic areas (parietal and frontal) starting from about270 msec. Hence, before semantic processing, a part of phonological information may be required. The conclusion could be got from above results in the present experimental conditions: 1. The basic visual feature processing starts from about 60 msec; 2. Orthographic processing starts from about 130 msec, and repeats at about 240 msec. The second processing is not simple repetition of the first one, but a higher level processing; 3. Phonological processing begins earlier than semantic, and their time-courses overlap; 4. Before semantic processing, a part of phonological information may be required; 5. The repetition, overlapping, and alternating of the orthographic, phonological and semantic processing of Chinese characters could exist in cognition. Thus the problem of whether phonology mediates semantics access is not a simple, but a complicated issue.