鄂尔多斯高原地下水固碳能力研究

利用不同深度地下水的二氧化碳含量,结合粒子示踪技术确定不同深度地下水的循环量,对鄂尔多斯高原地下水的固碳能力进行了估算。结果表明,浅层地下水二氧化碳含量为0.02～6.45 mg/L,中、深层地下水不含二氧化碳;浅层地下水的循环量占总循环量的82.4%,中、深层地下水的循环量占总循环量的17.6%;鄂尔多斯高原地下水的固碳能力约为2 470 t/a。     

Rheological and micro-Raman time-series characterization of enzyme sol–gel solution toward morphological control of electrospun fibers

Abstract

Rheological and micro-Raman time-series characterizations were used to investigate the chemical evolutionary changes of silica sol–gel mixtures for electrospinning fibers to immobilize an enzyme (tyrosinase). Results of dynamic rheological measurements agreed with the expected structural transitions associated with reacting sol–gel systems. The electrospinning sols exhibited shear-thinning behavior typical of a power law model. Ultrafine (200–300 nm diameter) fibers were produced at early and late times within the reaction window of approximately one hour from initial mixing of sol solutions with and without enzyme; diameter distributions of these fibers showed much smaller deviations than expected. The enzyme markedly increased magnitudes of both elastic and viscous moduli but had no significant impact on final fiber diameters, suggesting that the shear-thinning behavior of both sol–gel mixtures is dominant in the fiber elongation process. The time course and scale for the electrospinning batch fabrication show strong correlations between the magnitudes in rheological property changes over time and the chemical functional group evolution obtained from micro-Raman time-series analysis of the reacting sol–gel systems.     

Chronological Link Between the Abrupt Change of the Loess Grain Size Sequence and the Formation of River Terraces on the Eastern Margin of the Qinghai-Tibetan Plateau Since the Late Early-Pleistocene

Based on the study of magnetostratigraphy, magnetic susceptibility and grain size of Garz(e) A section on the southeastern margin of the Qinghai-Tibetan Plateau since the late early-Pleistocene, the basal age of Garz(e) loess is located at ～1.16 MaBP and a series of abrupt paleoclimatic changes is detected. The times of abrupt changes are of distinct series features, and the interval between each two adjacent abrupt changes is～50 kyr or ～100 kyr. The most significant abrupt changes occur at around 1.06, 0.85, 0.6, 0.46, 0.39 and 0.14 MaBP. There is a chronological link between the abrupt changes of paleoclimate and the formation of river terraces and it is almost simultaneous with a strengthening trend of neotectonic activities. Therefore, maybe the climatic transition contrail the timing of terrace formation, and the tectonic uplift originate potential energy and has a direct effect on channel incision,both the climatic transition and the tectonic uplift are important. Terraces are the products of the interaction of instable climatic variations and tectonic uplift. Like the loess-paleosol sequences, river terrace sequences are also controlled by the climate-tectonic coupling system and are ruled by climate-tectonic gyration with a ～100 kyr paracycle, which may be the short eccentricity period of the earth.     

气候变化对甘肃黄土高原土壤贮水量的影响

利用甘肃省黄土高原16个气象站1971~2000年气象资料、13个农业气象观测站及3个农业气象试验站土壤湿度资料,分析了近50年温度、降水及近30年土壤水分变化特征,用数理统计方法拟合了0~200 cm土壤贮水量动态变化,得出了土壤贮水量随气候变化的规律。研究表明,上世纪80年代以来,甘肃黄土高原土壤含水呈减少之势,0~200 cm土层土壤总贮水量春、秋季减少了40~90mm,夏季减少了20~36mm;土壤贮水适宜农作物生长的时段减少了2~3月,土壤水分匮缺的范围无论从时段及层次上都有所扩展。     

基于MapObjects的区域地质文献管理系统的建立

在进行区域地质研究的过程中,会涉及到大量的参考文献。当研究区域范围比较大、研究方法比较多的情况下,查找文献就会变成一项负担。本文以青藏高原的研究为例,利用VB开发了基于MapObjects的区域地质文献库管理系统。在对文献库进行综合管理的基础上,实现了由文献查找区域、在区域上查找文献等功能,很好地完成了地图与数据库的交互。     

Apparent solubility of drugs in partially crystalline systems

Using several griseofulvin samples, representing different solid-state structures, the solubility behavior of drugs in both one-state (totally ordered, semiordered or disordered) and two-state systems was studied. Special attention was directed towards the surface structure of the particles. The partially crystalline samples were obtained by milling the raw material (crystalline standard) or storing the quenched sample (amorphous standard). The solid-state structure of the materials was studied using x-ray diffraction (XRD), differential scanning calorimetry (DSC), isothermal microcalorimetry (IMC), and scanning electron microscopy (SEM). The saturation concentration of the materials was studied in suspensions containing different dispersion concentrations of drug after centrifugation and filtration, using spectrophotometry. In all cases these dispersion concentrations exceeded the solubility of the drug. The solubilities were plotted vs. dispersion concentrations for each sample. Several solubility plateaus were found. The lowest and highest solubility plateaus corresponded to the solubilities of crystalline and amorphous standards. These plateaus were reached at 8 and 44 µg/mL for crystalline and amorphous griseofulvin standards, respectively. An intermediate plateau served as an indication of the existence of a totally semiordered structure. This was reached at 19 µg/mL for griseofulvin. Any deviation from these plateaus was suggested to be indicative of the existence of heterogeneity on the surface structure, which in most cases could be described as a two state system. In such cases, the apparent solubility was a function of dispersion concentration, until at very high dispersion concentrations (4000-20,000 µg/mL) the saturation concentration of the totally disordered (44 µg/mL) or semiordered (19 µg/mL) one-state phase was reached. No reduction in these values was observed during storage for 50 days. It is thus concluded that, in partially crystalline systems, the saturation concentration is an interfacial phenomenon, which depends on the amount, reactivity, and solid-state structure of the exposed solid surfaces in equilibrium with the solution. A simplified solubility model is proposed to qualitatively describe the relationship between established apparent solubilities (saturation concentrations) and different combinations of solid-state structures.     

黄土高原土壤侵蚀的人为影响程度研究综述

人类活动对黄土高原土壤侵蚀的影响程度始终是黄土高原土壤侵蚀和黄河泥沙变化研究中的热门问题。人类活动对黄土高原土壤侵蚀影响研究主要可以分为地质地貌学法,土地利用变化法,气候演变法和水土保持措施法等四类,地质地貌学方法又包括黄河下游冲积扇沉积模式、地貌循环理论、侵蚀的自然脉动、沟谷侵蚀速率、侵蚀期与堆积期轮回等方法。不同研究方法对人类活动的影响评价存在明显异同。通过对现有研究方法、结果和观点的整理与讨论,认为应该提取和组织高时空分辨率的自然与人类活动要素,恢复地史与历史时期侵蚀面貌,探讨人类活动与水土流失变化的过程与机制,评价和预测人类活动对土壤侵蚀的影响。     

基于JSP的藏文古籍著录系统设计研究及实现

本文对藏文古籍著录的内容进行了具体的研究和分析,并对著录系统界面进行了设计和基本功能的实现。本系统包括了四个子系统,分别是书籍著录系统、铭刻著录系统、文书著录系统和讲唱著录系统。最后,本文详细介绍了书籍著录系统的设计和实现。     

黄土高原现状梯田和林草植被的减沙作用分析

2000年以来,黄河来沙明显减少。本文以黄土高原主要产沙区为对象,利用卫星遥感与实地调查相结合方法,获取2012年研究区各支流的梯田面积和质量信息,分析2010—2013年林草植被覆盖率及其较天然时期的变化;提出林草与梯田叠加作用地区的减沙量计算方法。基于流域尺度上构建的黄土丘陵沟壑区林草植被覆盖率与产沙系数、梯田比与减沙幅度之间的响应关系,计算在多年平均降雨条件下黄河龙门、北洛河状头、汾河河津、渭河咸阳和泾河张家山等5站以上现状林草植被和梯田的减沙能力,其值为10.65亿t,占该区天然年均来沙量的60%。     

基于决策树的藏语拉萨话三音子模型

对藏语拉萨话中单音子及三音子分布情况进行了统计,分析了在藏语大词表连续词表连续语音识别中建立上下文相关声学模型的必要性.选择音素为建模单元,根据藏语特点,建立以音节为单位的发音字典.讨论了利用决策树建立三音子模型的几个关键问题和基本算法,结合国际音标分类和经验知识,确定了38个藏语拉萨话音子类别集及相应的决策树问题集.建立了共20个发音人8 170句的训练语料,在HTK平台上建立和训练得到了基于决策树的藏语拉萨话三音子模型,并分析了不同隐马尔可夫模型状态数及高斯混合度下的识别结果,确定了一套藏语大词表连续语音识别的完整方案.