雾化进样石墨炉原子吸收光谱法的研究 Ⅰ.直接雾化进样装置及其性能

介绍一种自行设计和加工的直接雾化石墨炉进样装置的结构、工作原理和操作方法。该装置由微机控制与石墨炉加热程序同步工作,可以实现自动控制和自动测量。对雾化进样石墨炉分析的仪器参数和实验条件进行了研究和选择。结果表明,该装置与石墨炉结合具有自动化程度高、重现性好、样品利用率高和分析速度快等特点。     

Fast iterative solution of large undrained soil‐structure interaction problems

In view of rapid developments in iterative solvers, it is timely to re‐examine the merits of using mixed formulation for incompressible problems. This paper presents extensive numerical studies to compare the accuracy of undrained solutions resulting from the standard displacement formulation with a penalty term and the two‐field mixed formulation. The standard displacement and two‐field mixed formulations are solved using both direct and iterative approaches to assess if it is cost‐effective to achieve more accurate solutions. Numerical studies of a simple footing problem show that the mixed formulation is able to solve the incompressible problem ‘exactly’, does not create pressure and stress instabilities, and obviate the need for an ad hoc penalty number. In addition, for large‐scale problems where it is not possible to perform direct solutions entirely within available random access memory, it turns out that the larger system of equations from mixed formulation also can be solved much more efficiently than the smaller system of equations arising from standard formulation by using the symmetric quasi‐minimal residual (SQMR) method with the generalized Jacobi (GJ) preconditioner. Iterative solution by SQMR with GJ preconditioning also is more elegant, faster, and more accurate than the popular Uzawa method. Copyright © 2003 John Wiley & Sons, Ltd.     

Ammonium regeneration in intertidal sediments of the Yangtze estuary during air-exposure

The influences of exposure to the atmosphere on ammonium cycle in the intertidal surface sediments were in situ studied with a geochemical approach at a typical station in the Yangtze Estuary during three tidal cycles in September 2003. During an about 8-h emersion period of each diurnal tide, six high-resolution vertical profiles of adsorbed and dissolved ammonium were measured. It was observed that both adsorbed and dissolved ammonium generally had an increasing trend in sediment cores during the exposure. The rate of ammonium regeneration in sediments was estimated using the accumulation amount of ammonium including adsorbed and soluble fractions during the daytime emersion. The calculation result showed that there was relatively high ammonification rate (˜500 nmol N cm⁻³ day⁻¹), which reflected that organic nitrogen in sediments was quickly decomposed with a residence time of ˜52.7 days. Due to the dramatic temperature difference observed in sediment profiles, free convection was considered an important mechanism of regulating the efflux of produced ammonium into overlying waters. The total estimated amount of regenerated ammonium was ˜1.35×10⁵ t N year⁻¹ in the intertidal flat of the Yangtze Estuary, which occupied 7.6% of the total inorganic nitrogen annually transported to the estuarine ecosystem.     

中国和日本梅雨锋区（个例）结构的比较

通过１９８２年梅雨期的个例分析，研究和比较了中国和日本梅雨我的结构。分析表明：１．梅雨锋区系统对流层上部宽广的斜压区和对流层低层较狭窄的弱斜压区共同组成；２．在两个个例中，中国剖面上锋区均呈“椅”型结构。日本剖面上，６月呈均匀倾斜结构，７月略呈“椅型”，涡度场上中国剖面为相当正压结构，日本剖面为斜压结构；３．梅雨锋区系统可民是均匀斜压区在不均匀和加热情况下结构改变结果；４．中国大陆雨区高层大量潜热     

Properties of wave velocity for two types of granitoids at high pressure and temperature and their geological meaning

The wave velocity for two types of granitoids was measured using the analytic method of full-wave vibration at high pressure and high temperature. The laws of velocity changes for them differ with the pressure boost and temperature rise, and the velocity change of S-type is more violent than that of I-type. The “softening point” of compressional wave velocity (V μ) is also revealed during the measurement for two types of granitoids imitating the pressure and temperature at a certain depth. But the depth of “softening”, V_p after “softening” and the percentage of V_p’s drop around the “sofrening point” for two types of granitoids are obviously different. The depth of “softening” is 15 km approximately and V_p after “softening” is 5.62 km/s for S-type granitoid. But for I-type granitoid the depth of “softening” is 26 km approximately and V_p after “softening” is 6. 08 km/s. Through careful analysis of rock slices after the experiment, it was found that the “softening” of elastic-wave velocity is caused by the partial melting of granite. Combined with the results of geophysical prospecting, these results suggest that the low-velocity layers developing in the interior of Earth crust are related to thc partial melting of different types of granitoids. The formation of the low-velocity layer in the upper-middle Earth crust is closely related to the development of S-type granitoid, but that in the lower Earth crust is closely related to the development of I-type granitoid.     

Budd—Chiari综合征的CT评价

回顾性分析了５２例Ｂｕｄｄ－Ｃｈｉａｒｉ综合征的ＣＴ表现，ＣＴ显示肝尾叶增大５０例（９６％），肝脏呈低度密度或密度不均，４２例（８１％）肝静脉未明显，２２例（４２％）见有肝内侧枝血管，４９例（９４％）有肝外侧枝血管，作者认为ＣＴ检查对Ｂｕｄｄ－Ｃｈｉａｒｉ综合征有较高的诊断价值。     

中国地质统计学（空间信息统计学）发展的回顾与前景

讨论了地质统计学（空间信息统计学）发展的若干问题，其内容包括４部分：１．地质统计学的理论及方法；２．关于软件系统的现状；３．关于实际应用；４．地质统计学发展前景的若干看法。     

平和县灵通山旅游开发策略

闽南漳州市的平和县灵通山，是福建省第三批省级风景名胜区，但目前仍处于旅游地的参与阶段。要进入发展阶段，实现景区开发的经济、社会和环境效益，必须在明确旅游开发主体的前提下，挖掘旅游资源潜力、科学规划与设计景点、塑造鲜明的旅游形象并有针对性地进行旅游市场营销。此外，改善交通状况、完善景区解说系统、营造良好的旅游社会环境也是必不可少的重要策略。     

基于学籍地址和地理编码的乡村小学教育资源空间可达性分析

基于“学籍信息中的家庭地址承载了学生空间位置”这一假设,通过学籍信息收集了湖南省株洲县小学生的家庭地址,借助高德开放平台提供的地理编码和POI搜索服务,获得到了株洲县小学生的空间位置和分布,并基于最短路径分析和高斯型两步移动搜索法分析了株洲县小学教育资源的空间可达性及其特征,尝试为区域教育资源的空间均衡性分析与规划配置提供新的数据源和方法借鉴。结果表明：① 基于学籍地址和地理编码技术能够较准确地获取株洲县小学生的空间分布。② 株洲县小学生就近入学距离的最大值、平均值和中位数分别为11.83 km、2.10 km和1.81 km,就近入学距离小于2.0 km的学生仅占55.46%,为株洲县兼顾公平和效率的教育资源配置工作带来了挑战。③ 株洲县北部城镇地区因学校数量较多,平均就近入学距离较小,教育资源的空间可达性普遍较高,且空间差异小,均衡性好;而东南部的乡村地区,平均就近入学距离较大,教育资源的空间可达性普遍较低,且空间差异大。④ 基于情景分析,在不造成局地生源稳定性问题的前提下,新增3所学校后,东南部地区的平均就近入学距离和教育资源的空间可达性有很大的改善,龙潭镇和龙门镇的平均入学距离由3784 m和3520 m降低到3116 m和2636 m,教育资源的空间可达性分别由0.0492和0.0982提高到0.0762和0.1496。