吉林金川西大甸子泥炭沉积中火山物质的发现及其意义附：泥炭中胡敏酸的稳定碳同位素值（δ<'13>C）作为古气候代用指标可行性研究

泥炭以发育广泛、连续沉积好、沉积速率大（可达1mm/a甚至更大）、记录丰富等特点,正成为过去全球变化研究的良好综合地质档案.参考冰芯、黄土、深海沉积物等中矿物固体的研究思路和方法,希望能对泥炭中可能存在的火山物质和其它风粉尘进行研究.在对吉林金川西大甸子泥炭样品的处理过程中,摸索出一套泥炭样品中固体物质（如火山物质）初步的处理、分析方法;并对金川西大甸子干玛珥泥炭沉积中部一段泥砂状物质进行鉴定,首次发现火山玻璃,判断这些泥砂物为火山灰砂.目前研究表明,泥炭纤维素的δ<'13>C序列能较好地反映古气候变化,那么泥炭中胡敏酸的δ<'13>C序列可否也能反映古气候变化,该文对此作了初步研究.用碱溶酸沉淀方法从泥炭中提取出所谓的胡敏酸,用燃烧法将胡敏酸、纤维素中的碳转化为CO<,2>气体,测定它们的稳定碳同位素组成（δ<'13>C）.与能较好地反映气候变化的纤维素δ<'13>C序列相比,胡敏酸的δ<'13>C序列反映气候变化不明显.

13万年以来洛川黄土剖面中营养元素的分布及演化规律

洛川剖面以其厚度大，沉积连续，并完整地记录了第四纪以来陆相环境、气候变化的信息而举世闻名，是陆相沉积序列中研究最为成熟的黄土剖面，被定为国际标准的黄土剖面。学者们对黄土剖面经过多年的研究，获得了许多宝贵的成果，例如，磁化率、粒度、地球化学等指标的建立，黄土物质来源问题的探讨，东亚季风变迁的研究，及大气环流模型的建立等等。这些成果在解释全球性尺度上的古气候变化以及在预测未来气候变化趋势上具有重要的理论指导意义。上述成果着重从物理和化学的角度来展开研究的，而如何从生物地球化学的角度来研究局部的气候环境变化及其对全球变化的响应问题，以便更好地弄清楚气候变化的机制、周期性及影响因素，预测未来气候的变化，科学防治环境污染，合理利用自然环境，促进人类社会进步呢。这是目前黄土研究中较薄弱的地方。因此，本文在前人工作的基础上，首次将营养元素的概念较系统地引入到黄土古气候的研究中来，初步讨论了营养元素（C，N，P，K）在洛川黄土剖面中的分布和演化规律，获得了如下凡点新的认识：1．13万年来洛川黄土剖面中有机碳的含量在0.14％-0.54％之间变化，平均含量为0.26％。在时间上，有机碳高一低值的变化特征对应不同的气候时期。干冷气候条件下形成的黄土L1有较低的有机碳含量，湿热气候条件下发育的古土壤有较高的有”机碳含量。在马兰黄土中，间冰阶形成的L1SS1中有机碳含量高于始冰阶和盛冰阶形成的L1LL1、L1LL2中的有机碳含量，表现出低的有机碳含量对应于冷期，高的有机碳含量对应于暖期。有机碳的这种变化特征，与磁化率的变化趋势一致，在一定程度上反映了不同时期植被的发育程度。通过洛川剖面（109°25′E，35°45·N）与段家坡剖面（109°12′E，34°25′N）有机碳的对比可知，在空间上，从黄土高原的西北到东南，同一时期黄土剖面中有机碳的含量呈逐渐增加的变化趋势，这与地理上的气候变化是一致的。因此，时空上有机碳的变化特征反映黄土高原地区东亚夏季风强弱周期性变化的特点。2．洛川黄土剖面中的氮由有机氮、固定钱态氮和速效态氮组成，其中前两者为主要部分，占总氮的95％以上。有机氮占总氮的55％-76％，在181μg·g-15689μg-1之，间变化平均值为299μg-1彭，其在剖面中的分布与有机碳极为相似，在黄土LI中有较低的有机氮，在古土壤S1中有较高的有机氮，并且在马兰黄土中，间冰阶形成的L1SS1中有机氮含量高于始冰阶和盛冰阶形成的L1LL1、L1LL2中的有机氮，其高一低值的分布与黄土一古土壤中冷一暖变化相互对应。有机氮的含量变化在一定程度上也反映了植被的生长发育程度，同样揭示了东亚夏季风对黄土高原的影响。速效性氮（交换性钱态氮和水溶性钱态氮）在洛川黄土剖面中的含量低，主要在Oμg·g-1-11.5μg·-1之间变化，在古土壤51和间冰阶时期形成的弱土壤化黄土LISSI中有较高的值，反映了速效性氮与土壤湿度和粘粒的含量有关。由于速效性氮和固定按态氮在黄土剖面中的振荡幅度不大，总氮的分布基本与有机氮一致，其在黄土剖面中的变化主要受有机氮变化的制约。3．黄土一古土壤层位中固定钱态氮占总氮的24％-43％，其含量在140μg·210μg·g-1之间变化。黄土层中的固定钱态氮含量低于相邻的古土壤。

5-13岁儿童对惯性运动的认知发展

Research on naïve physics investigates children’s intuitive understanding of physical objects, phenomena and processes. Children, and also many adults, were found to have a misconception of inertia, called impetus theory. In order to investigate the development of this naïve concept and the mechanism underlying it, four age groups (5-year-olds, 2nd graders, 5th graders, and 8th graders) were included in this research. Modified experimental tasks were used to explore the effects of daily experience, perceptual cues and general information-processing ability on children’s understanding of inertia. The results of this research are: 1) Five- to thirteen-year-olds’ understanding of inertia problems which were constituted by two ogjects moving at the same spped undergoes an L-shaped developmental trend; Children’s performance became worse as they got older, and their performance in the experiment did not necessarily ascend with the improvement of their cognitive abilities. 2) The L-shaped developmental curve suggests that children in different ages used different strategies to solve inertia problems: Five- to eight-year-olds only used heuristic strategy, while eleven- to thirteen-year-olds solved problems by analyzing the details of inertia motion. 3) The different performance between familiar and unfamiliar problems showed that older children were not able to spontaneously transfer their knowledge and experience from daily action and observation of inertia to unfamiliar, abstract inertia problems. 4) Five- to eight-year-olds showed straight and fragmented pattern, while more eleven- to thirteen-year-olds showed standard impetus theory and revised impetus theory pattern, which showed that younger children were influenced by perceptual cues and their understanding of inertia was fragmented, while older children had coherent impetus theory. 5) When the perceptual cues were controlled, even 40 percent 5 years olds showed the information-processing ability to analyze the distance, speed and time of two objects traveling in two different directions at the same time, demonstrating that they have achieved a necessary level to theorize their naïve concept of inertia.

Acid catalyzed synthesis of ordered bifunctionalized mesoporous organosilicas with large pore

Thiol-functionalized mesoporous ethane-silicas with large pore were synthesized by co-condensation of 1,2-bis(trimethoxy-sily)ethane (BTME) with 3-mercaptopropyltrimethoxysilane (MPTMS) using nonionic oligomeric polymer C1H (OCH(2)-CH(2))(10)OH (Brij-76) or poly(alkylene oxide) block copolymer (P123) as surfactant in acidic medium. The results of powder X-ray diffraction (XRD), nitrogen gas adsorption, and transmission electron microscopy (TEM) show that the resultant materials have well-ordered hexagonal mesoscopic structure with uniform pore size distributions. (29)Si MAS NNR, (13)C CP-MAS NMR. FT-IR, and UV Raman spectroscopies confirm the attachment of thiol functionalities in the mesoporous ethane-sificas. The maximum content of the attached thiol group (-SH) in the mesoporous framework is 2.48mmol/g. The ordered mesoporous materials are efficient Hg(2+) adsorbents with almost every -SH site accessible to Hg(2+). In the presence of various kinds of heavy metal ions such as Hg(2+), Cd(2+), Zn(2+), Cu(2+) and Cr(3+), the materials synthesized using poly(alkylene oxide) block cooollxmier (Pluronic 123) g(2+), as surfactant show almost similar affinity to Hg(2+), Cd(2+), and Cr(3+), while the materials synthesized using ofigomeric polymer C(18)H(37)(OCH(2)CH(2))(10)OH (Brij-76) as surfactant exhibit high selectivity to Hg(2+). (C) 2004 Elsevier Inc. All rights reserved.