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本文采用氢感应法,测定低温水热条件下Pt 的H2 渗透常数k ,并可根据H2 渗透来计算实验体系的氧逸 度。这种方法无需依赖H2 在氧缓冲体系与实验体系间平衡状态的到达, 但要求有精确的氢渗透常数。本研 究在200 ℃, NNO 及HM氧缓冲的实验条件下,通过测定氢感应体系中淬火溶液Cl - 浓度的变化, 计算求得Pt 的H2 渗透常数k 为10 - 13~10 - 14数量级。并讨论了在实验及数据处理过程中对H2 渗透常数k 可能带来的误 差及影响因素。

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气溶胶对气候和人类的健康都有重要影响。因此,研究大气总悬浮颗粒物(TSP)的化学组成和物理特性对更深入地了解气溶胶对气候和人类健康的影响具有重要意义。贵阳是中国受燃煤污染比较严重的城市之一,大气中高含量的SO2是其最明显的特征。尽管最近几年空气质量有所改善,但是该区的大气污染问题还比较严重,空气质量仍然不容乐观。我们于2005年1月1日到2005年12月31日在中科院地球化学研究所内全年采集总悬浮颗粒物(TSP)样品,分析测试了其主要无机离子(F-、Cl-、SO42-、NO3-、NH4+、K+、Na+、Ca2+和Mg2+)的化学性质,并结合当地的气象参数(温度,风速,降雨量和相对湿度)系统地研究了TSP及其水溶性无机离子的季节变化特征。本论文的主要结论有: 1. TSP的浓度变化范围为36.91~313.44µg/m3,年均值106.60µg/m3;各离子摩尔浓度的大小顺序为:SO42-> NH4+> Ca2+ > NO3-> K+ > Na+ > Cl- > Mg2+ > F-;SO42- (23.04±12.16µg/m3)和NH4+(3.05±2.23µg/m3)是最主要的离子,分别占总离子摩尔数的37%和30%。TSP及其组分都有明显的季节变化,TSP、Cl-、SO42-、NO3-、NH4+、K+、Na+、Ca2+和Mg2+浓度的冬/夏比值分别为:1.29、5.23、1.35、2.37、1.73、1.22、1.84、1.23和1.02。 2. 温度对TSP及其水溶性无机组分的影响呈现一定的季节变化模式,冬天随温度的升高TSP及其水溶无机组分的浓度也升高,夏天随温度的升高TSP及其水溶性无机组分的浓度降低。但是从全年来看,温度与TSP及其水溶性无机组分之间有弱的负相关性,即随温度的升高,TSP及其水溶性无机组分的浓度有不同程度的下降。相对湿度与TSP及其水溶性无机组分之间存在明显的负相关关系,即随大气相对湿度的增加,TSP及其水溶性无机组分的浓度下降。在相对湿度与TSP及其水溶性无机组分浓度的日变化图中表现为相对湿度的波谷与TSP及其水溶无机组分的浓度的波峰相对应。风速与TSP及其水溶无机组分的浓度之间呈现弱的负相关性。在贵阳,风速对TSP及其水溶无机组分的影响主要表现为扩散作用和稀释作用,由风速导致的尘土再悬浮作用并不明显。雨量对TSP及其水溶性无机组分的影响主要是湿清除作用,具体表现为无雨天TSP及其水溶性无机组分的浓度较雨天高。影响TSP、Ca2+、Mg2+和F-的主要气象参数是相对湿度(RH)和风速,影响SO42-、NO3-、NH4+和Cl-的主要气象参数是温度。 3. 贵阳大气总悬浮颗粒物(TSP)总体偏酸性,TSP水溶液pH值的年均值为6.27±0.41,与总阴离子与总阳离子的当量比Q的年平均值为0.82一致;TSP中高含量的SO42-是贵阳的TSP显酸性的主要原因。 4. NH4+与SO42-和NO3-的相关系数(R)分别为0.85和0.65,NH4+与SO42-的摩尔比值为0.8,说明贵阳TSP中的NH4+主要以(NH4)2SO4的形式存在。Ca2+和Mg2+有较好的相关性(R=0.72)和相似的变化特征,说明二者可能有共同的来源。 5. 2005年贵阳TSP中SO42-/ Ca2+的平均值为13.64,几乎是干净大陆SO42-/ Ca2+的本底值的20倍,说明贵阳的大气污染主要是人为因素所致。NO3-/SO42-的平均值为0.15,说明固定源对贵阳气溶胶的贡献比移动源(通常指交通工具所排放的尾气)对气溶胶的贡献大;

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新疆北部地区属于中亚造山带的关键部位,有独特的构造岩浆活动和成矿作用,自二十世纪八十年代早期以来一直是国内外地质研究的热点地区之一。准噶尔盆地两侧大面积出露的A型花岗岩及相关矿床是该区的重要研究对象。尽管已有的研究积累了一定成果,但对一些关键问题,特别是对于A型花岗岩形成时代和成因的认识还存在较大争议。另一方面,传统观点认为锡矿床主要与演化的过铝质S型花岗岩有关,但在东准噶尔卡拉麦里构造带,多个中小型锡矿床产于A型花岗岩体内或岩体与围岩的接触带附近,花岗岩与锡矿的成因联系有待深入研究。 本论文以准噶尔盆地两侧的三条A型花岗岩带(包括东准噶尔的卡拉麦里和乌伦古河A型花岗岩带、西准噶尔的达拉布特A型花岗岩带)为研究对象,对其中的一些A型花岗岩体开展了详细的年代学和地球化学研究,并以这些资料为基础,探讨了A型花岗岩的岩石成因及其构造和成矿意义。概括起来,主要得到以下结论性认识: (1)锆石U-Pb年代学结果显示,卡拉麦里铝质和碱性A型花岗岩都形成于302~310Ma左右;乌伦古河碱性A型花岗岩形成于305~320Ma,而铝质A型花岗岩形成于270~280Ma;西准噶尔达拉布特铝质A型花岗岩形成于295~305Ma。这些高精度的同位素年龄资料进一步确证了准噶尔地区大面积发育的A型花岗岩是该区后碰撞阶段的岩浆作用产物。 (2)三个构造带的碱性花岗岩和碱长花岗岩都具有典型A型花岗岩的矿物学和地球化学特征。在主量元素上它们富硅、富碱、低铝、贫钙镁,在微量元素上它们明显富集Rb、K、Th等大离子亲石元素及Zr、Hf等高场强元素和稀土元素而亏损Ba、Sr、Eu。根据地球化学组成,苏吉泉黑云母碱长花岗岩是典型的铝质A型花岗岩,而不是前人提出的S型花岗岩。 (3)三个构造带的A型花岗岩均有较高的正Nd(T)值和大于成岩年龄的两阶段Nd同位素模式年龄,它们的地质特征和地球化学组成难以用幔源岩浆高度分异的成岩模式解释。这些A型花岗岩的岩浆很可能是花岗闪长质岩浆分异结晶作用的产物,而花岗闪长质岩浆则起源于具亏损地幔同位素组成的玄武质洋壳和少量陆壳物质的部分熔融。 (4)东准噶尔早二叠世A型花岗岩的发育表明该区后碰撞阶段的花岗岩浆作用持续时间较长(约60Ma),这些花岗岩与晚石炭世A型花岗岩在地球化学组成上的差异揭示了东准噶尔乃至新疆北部在早二叠世的陆壳垂向生长。 (5)萨惹什克锡矿石中辉钼矿的Re-Os同位素年龄值(307Ma)与赋矿的萨北碱性花岗岩中锆石的U-Pb年龄值(306Ma)有很好的一致性,而且辉钼矿的Re含量低,表明成矿物质可能主要源于地壳。时间和物源的证据反映该区A型花岗岩与锡矿床具有密切的成因联系。

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矿物PVT状态方程是研究矿物在一定温压条件下的晶胞体积与温度、压力之间的关系,依据这个基本关系,可以了解矿物在高温高压下的密度、弹性、热膨胀等性质。矿物PVT状态方程的研究可以了解矿物在地球深部存在的结构状态,为进一步的理论计算提供基础的数据,其结果也可以与天然和人工地震的地震波反演的结果对比,对地球深部的地质作用过程、物质结构状态和组成进行限制。然而,目前矿物PVT状态方程的研究主要集中在氧化物矿物和上地幔主要矿物(橄榄石和辉石)及其高压相(瓦兹利石、林伍德石、方镁铁矿、Majorite、Mg-Perovskite、Ca-Perovskite)的研究上,对石榴石、尖晶石等地幔常见副矿物和硫化物矿物的PVT状态方程的研究很少。 作者在参与搭建并完善金刚石压腔外加温系统的基础上,利用北京同步辐射X射线衍射实验技术结合金刚石压腔外加温技术对天然铁铝榴石、锰铝榴石、铬尖晶石进行了PVT状态方程的研究,同时对闪锌矿、辰砂、方铅矿、辉钼矿、辉锑矿等硫化物矿物进行了相变及状态方程的研究。结合前人研究成果,讨论了类质同象置换对镁铝-铁铝系列石榴石、锰铝-铁铝系列石榴石、尖晶石和硫化物矿物相变及状态方程的影响。获得了以下研究结果: 1)镁铝-铁铝系列石榴石和锰铝-铁铝系列石榴石的体弹模量都随着铁铝榴石组分的增加而增大。其主要原因是在二价阳离子位置上Fe2+取代了Mg2+、Mn2+。在镁铝-铁铝榴石系列中Mg2+的共价键半径(1.36Å)要大于Fe2+的共价键半径(1.17Å),而Mg2+-O键长(2.270Å)与铁铝榴石中的Fe2+-O(2.299Å)键长基本相当。在锰铝-铁铝榴石系列中, 尽管Mn2+的共价键半径(1.17Å)与铁铝榴石中的Fe2+共价键半径(1.17Å)相等,但是Mn2+-O键长(2.326Å)大于Fe2+-O键长(2.299Å)。较小的键长和共价键半径将会增强离子间的结合力,从而具有较强的抗压缩能力,因此随铁铝榴石组分的增加,镁铝-铁铝榴石系列和锰铝-铁铝榴石系列具有较大的体弹模量。 2)首次获得了铬尖晶石((Mg0.6766Fe0.2808Na0.0073Ti0.0014)0.9661(Cr1.4874Al0.5367)2.0241O4)的体弹模量的温度导数。结合前人关于其他组分尖晶石的实验结果发现,尖晶石中在四面体位置上发生Fe2+-Mg2+置换对体弹模量的影响要大于在八面体位置上发生Cr3+-Al3+置换对体弹模量的影响。而造成铬尖晶石的体弹模量值比其他组分尖晶石的体弹模量值大的主要原因也是四面体位置上的Fe2+-Mg2+的类质置换。 3)依据获得的尖晶石和石榴石的状态方程计算了不同地幔岩模型(橄榄岩和榴辉岩模型)的密度值在上地幔温压条件下的变化情况。结果表明,在尖晶石二辉橄榄岩模型中尖晶石含量的改变(2%-10%)会引起较大的密度变化(2.2%);在石榴石二辉橄榄岩(石榴石含量14%-20%)和榴辉岩(石榴石含量37%-45%)模型中石榴石含量的变化几乎未引起其密度值的变化,但石榴石是这两种地幔岩模型中的重要组成矿物。 4)首次获得了辰砂的Cinnabar相、方铅矿的B33相、辉钼矿、辉锑矿体弹模量的温度导数和热膨胀系数。讨论了闪锌矿、辰砂、方铅矿的相变情况。 5)总结了锌的、汞的、铅的硫族化合物发生结构相变的规律。认为造成锌的、汞的、铅的硫族化合物的相变压力随阴离子原子序数的增加(S→Se→Te)而逐渐减小的原因是:元素周期表中相对较大原子序数的原子具有更多的核内电子,引起价电子及导带电子的有效位能相对变弱,引起电离能降低,因此在相对较低的压力下就容易发生结构相变。 6)分析了ZnS中Fe2+替代Zn2+、Sb2S3-Bi2S3、MoS2-WS2以及同族相同结构不同组分的简单硫化物矿物的阴、阳离子对体弹模量值的影响。认为简单硫化物矿物的体弹模量值取决于阴、阳离子的离子半径、电负性以及键长。

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萨瓦亚尔顿金矿床是我国90年代金矿地质工作者在新疆西南天山地区寻找穆龙套型金矿床的一个突破。本文通过对新疆萨瓦亚尔顿金矿床的矿石矿物组成、稀土元素地球化学、同位素地球化学以及流体包裹体特征等方面的研究,探讨了萨瓦亚尔顿金矿床地质地球化学特征、金的赋存状态及成矿流体特征、成矿流体来源,提出了该矿床的成矿机制,取得如下认识:1.流体包裹体岩相学研究表明,萨瓦亚尔顿金矿床的流体包裹体主要为V+L相和富CO_2相包裹体,前者为NaCl-H_2O体系,后者主要有L_(CO2)、L_(CO2)+L、V_(CO2)+L、V_(CO2)+L_(CO2)+L相包裹体;并发现极少量含子晶流体包裹体。2.通过流体包裹体显微测温学研究,表明金矿床的均一温度成矿早阶段为270~320 ℃,成矿主阶段为170~250 ℃,成矿晚阶段为110-250 ℃,呈逐渐降低的趋势,低温成矿作用明显。3.单个流体包裹体的激光拉曼分析表明,流体包裹体中除含有CO2之外,还含有一定量的N_2和CH_4。4.成矿物质来源的复杂性。萨瓦亚尔顿金矿床矿石中微量元素组成、稀土配分模式大都反映了成矿金属物质主要来自赋矿地层本身。金属硫化物的6345:-3.4‰~+2.6‰,西南天山地区下古生界地层中广泛存在各类火山岩可能是该矿床的主要硫源,部分可能有深部物质的参与。矿石中主要脉石矿物石英和菱铁矿 中包裹体水的氢氧同位素组成为δD = -72%~-62‰,δ~(18)O = -11.6‰~+5.4‰。成矿流体主要为大气降水补给的地下卤水,并有少量岩浆水的混合。5.Ar-Ar同位素地球化学研究表明,萨瓦亚尔顿金矿床的主要成矿时代为印支晚期,210 Ma。6. 对矿石中的流体包裹体进行了温度、压力、成分、pH、含盐度等的分要的,并系统的进行了矿床形成时的物理化学条件的理论计算,基中包括EH、PH、f_(O_2)、f_(S_2)等及金在矿液运移中的搬运形式。指出减压过程或伴生沸腾的减压过程,是矿床形成过程中矿质卸载的基本机制,此外,酸蚀变过程(如绢云母化等)中由于H~+的消耗促进了溶液中pH值的升高;含高炭质的围岩,降低了矿液的氧逸度以及含矿热液与地表下渗冷水的混合等诸多因素,则是矿订形成的辅助机制。

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在开放(P_水270-5.806 * (1000/T) (11.26M) 20%: 1np = 14.580 - 5.831 * (1000/T) (16.9M) 30%: 1np = 14.412 - 5.519 * (1000/T)根据这些等式求出了在不同压力、温度下各种浓度的CaCl_2-H_2O流体的水逸度系数(£)。由于至目前为止在文献中还没有这方面的实验研究报道,因而无法评价这一新方法所获得的数据的准确性。利用求得的£值,在本篇论文中建立起了不同浓度的CaCl_2-H_2O流体影响钙蒙脱石脱水温度的热力学模式:TD' = [T_1*T_D*(ΔH_(tw) + ΔH_(sv)~盐)/[T_1*(ΔG + ΔH_(dn)~水)-T_D~* (ΔH_(av)~水-ΔH_(sv)~盐)在0-1M浓度范围内,可以认为ΔH_(dh)~水≈H_(dh)~盐,等式变为:TD' = (TD*ΔH_(dh))/(ΔG + ΔH_(dh))根据这个模式,能推导出在实验浓度范围内,钙蒙脱石在盐水体系中的脱水温度。通过本次论文的实验研究知道在一般沉积盆地的埋芷条件下,钙蒙脱石矿物不会发生简单的脱水作用。在缺乏K~+和低盐度的环境中,含水相蒙脱石可稳定地存在在一定深度的地壳中因而不可忽略蒙脱石在海洋化学和俯冲带水来源中的作用。在选择处理簇射性废料的回填料(backfill)时,如其它条件相同,则应优先选择钙蒙脱石,而不是蛭石。在石油采矿和勘探工程中,因压力释放所造成的蒙脱石的脱水作用可能是使钻井变大和塌方的可能性原因之一。

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In the present study, 520 questionnaires about general self–efficacy, achievement goal orientation, learning motivation and time management were delivered to university students. The students were randomly chosen from Communication University of China, Central University of Finance and Economics, Capital University of Business and Economics and Shanxi University. 495 responses were valid , in which 225 majoring in liberal arts and 270 majoring in natural sciences. The influences of these four factors on students’ academic achievements were explored. And the gender differences in General self-efficacy, achievement goal orientation, learning motivation and time management were analyzed in the present study too. It was found that: 1) There were gender difference on academic achievements. The scores’ of female students were higher than males’. 2) Significant gender differences were found in four considered factors which indicated that female students got higher scores than male students; 3) There were close relations between the four considered factors and students’ academic achievements. There were also obvious relations among the four factors. 4) University students’ academic achievements could be well predicted by their general self-efficacy, achievement goal orientation, learning motivation and time management.

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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.

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After revising Russell Motives for Smoking Questionnaire(RMSQ,1974), 317 smoking students and 270 non-smoking students in Beijing are studied. Factor analysis on RMSQ showed that there are four factors: Indulgent, Stimulant/Sedative, Addictive and Social, which cause students to smoke. All the four motives are positively correlated to Psychoticism, and excluding Stimulant /Sedative, the other motives have a negative correlation with the scores on the EPQ Lie sclae. The revised RMSQ has a high reliability and validity in China.

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The titanium species existing in titanium silicalite TS-1, which is prepared by hydrothermal method, were investigated using chemical analysis, XRD, FT-IR, Si-29 MAS NMR, UV-VIS, ESR. It has been observed that several kinds of titanium species may exist in titanium silicalite. The form that titanium atoms incorporate into the framework of titanium silicalite synthesized using tetrapropylammonium bromide (TPABr) as template differs from that using the classical method. But, the symmetry of titanium silicalite, changes from monoclinic to orthorhombic with the increase of titanium content in both methods. The Ti-O-2(-) originated from framework titanium and H2O2 has the moderate stability and may be active site in oxidation reaction. TS-1 synthesized using TPABr as template does not contain anatase, but contains a kind of partly condensed titanium species with six-fold coordination. The titanium species may correspond to 270-280 mn band in UV-VIS spectra and also can form Ti-O-2(-). But, this kind of Ti-O-2(-) is very stable and cannot be catalytic active site. So, the six-fold coordination titanium species may be inactive in both the oxidation reaction and the decomposition of H2O2. The hypothesis has been further proved by the phenomena that the titanium species is easily washed off using acid, and acid treating will not influence the catalytic performance of TS-1. (C) 2001 Elsevier Science B.V. All rights reserved.

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A method with carbon nanotubes functioning both as the adsorbent of solid-phase extraction (SPE) and the matrix for matrix assisted laser desorption/ ionization mass spectrometry (MALDI-MS) to analyze small molecules in solution has been developed. In this method, 10 muL suspensions of carbon nanotubes in 50% (vol/vol) methanol were added to the sample solution to extract analytes onto surface of carbon nanotubes because of their dramatic hydrophobicity. Carbon nanotubes in solution are deposited onto the bottom of tube with centrifugation. After removing the supernatant fluid, carbon nanotubes are suspended again with dispersant and pipetted directly onto the sample target of the MALDI-MS to perform a mass spectrometric analysis. It was demonstrated by analysis of a variety of small molecules that the resolution of peaks and the efficiency of desorption/ ionization on the carbon nanotubes are better than those on the activated carbon. It is found that with the addition of glycerol and sucrose to the dispersant, the intensity, the ratio of signal to noise (S/N), and the resolution of peaks for analytes by mass spectrometry increased greatly. Compared with the previously reported method by depositing sample solution onto thin layer of carbon nanotubes, it is observed that the detection limit for analytes can be enhanced about 10 to 100 times due to solid-phase extraction of analytes in solution by carbon nanotubes. An acceptable result of simultaneously quantitative analysis of three analytes in solution has been achieved. The application in determining drugs spiked into urine has also been realized. (C) 2004 American Society for Mass Spectrometry.