极限波浪运动特性的非线性数值模拟

利用时域高阶边界元方法建立了模拟极限波浪运动的完全非线性数值模型,其中自由水面满足完全非线性自由水面条件.采用半混合欧拉-拉格朗日方法追踪流体瞬时水面,运用四阶Runge-Kutta方法更新下一时间步的波面和速度势,同时应用镜像格林函数消除水槽两个侧面和底面上的积分.研究中利用波浪聚焦的方法产生极限波浪,并且在水槽中开展了物理模型实验,将测点试验数据与数值结果进行了对比,两者吻合得很好.对极限波浪运动的非线性和流域内速度分布进行了研究.     

无限水深聚焦波完全非线性数值模拟

基于势流理论提出一种新的高阶边界元方法对无限水深的聚焦波浪进行完全非线性数值模拟.自由水面满足完全非线性边界条件,模拟波浪的非线性效果可以达到更高阶.利用镜像原理,建立一种全新的格林函数应用到无限水深的数值波浪水槽中,以致于两无限深水槽侧壁的积分可以被排除.为了产生相应的入射波和吸收出流波浪,一个由点源组成的造波装置被布置于计算域内,同时人工阻尼层被用来吸引出流波浪,由波浪聚焦的方法得到极限波浪.通过开展线性和完全非线性聚焦波浪的数值实验及与理论解对比,验证本数值模型可以用来模拟无限深水域的极限波浪,且在出流边界没有反射.     

地理信息元数据的管理探讨

对数据仓库、元数据等进行了简单介绍,并针对地理信息系统中元数据的作用、内容进行了阐述,在此基础上,对地理信息系统中元数据的管理方法提出了建议,供同行参考。     

BTEX anomalies used as indicators of submarine oil and gas reservoirs

It is a conventional method for petroleum prospecting to generally use paraffin hydrocarbon as basic indexes of oil and gas. This conventional geochemical technology, however, shows some limits in the prospecting as paraffin is vulnerable to influences from human and biologic activities. Consequently, BTEX (short for benzene, toluene, ethyl benzene and xylem, which are direct biomarkers) among aromatic hydrocarbon series has been taken into account for the oil and gas prediction. Domestic and foreign study results demonstrate that BTEX is hardly disturbed and can well indicate oil and gas reservoirs. Based on measured data from a South China Sea area, the present authors have used self-developed visual assessment software for petroleum prospecting has been used to process data, strip background anomalies, and outline significant BTEX anomalies. By comparison with stratigraphic profiles of the target area, it is confirmed that BTEX is a good indication of marine oil and gas during the petroleum prospecting.     

Study on General Performance of Jack-up Under Elevated Condition

Method of checking for jack-up elevated performance including leg structure strength, fixation system or jacking system bearing capacity, pre-load requirements, spud can bearing capacity and overturning stability is suggested in this paper. As an example, a jack-up with truss legs is analyzed by finite element analysis method. This paper may be helpful to the rig owners, operators and designers.     

壳聚糖硫酸酯金属配合物的抗氧化活性

以吩嗪硫酸甲酯-NADH为超氧阴离子自由基(O_2~(·-))产生、检测体系和EDTANa_2-Fe(Ⅱ)-H_2O_2为羟自由基(~·OH)产生、检测体系,对壳聚糖硫酸酯铜、锌配合物和不同分子质量壳聚糖进行了抗O_2~(·-)和~·OH自由基的活性研究.结果表明,壳聚糖硫酸酯金属配合物对于O_2~(·-)自由基的清除能力明显高于壳聚糖,在质量浓度为0.025 g/L时,壳聚糖硫酸酯铜配合物对O_2~(·-)自由基的清除能力达到94.18%,壳聚糖硫酸酯锌配合物达到93.19%;壳聚糖硫酸酯铜、锌配合物对~·OH自由基的清除能力(67.39%、60.46%)低于相同分子质量的壳聚糖(88.06%),而高于高分子质量壳聚糖761 ku(18.71%);壳聚糖分子质量大小对O_2~(·-)和~·OH自由基的清除能力有较大影响,质量浓度为1.6 g/L壳聚糖分子质量为20 ku时,对O_2~(·-)清除率达54.69%,而分子质量在761 ku时,对O_2~(·-)清除率仅为35.50%;各样品对O_2~(·-)和~·OH自由基的清除能力均随着质量浓度的增加而上升,壳聚糖硫酸酯铜、锌配合物在相当低的浓度下(0.025 g/L)就可以达到明显清除O_2~(·-)自由基的效果(≥90%).     

Application of matter-element model in soil nutrient evaluation of ecological fragile region

On the basis of the soil environment investigation in Da'an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter (SOM), total N (TN), total P (TP), total K (TK), available N (AN), available P (AP) and available K (AK) were chosen as the evaluation factors. A regional soil nutrient evaluation model was developed based on the matter-element model. The results show that the soil samples with nutrient grade Ⅱ-Ⅴ respectively account for 10%, 30%, 32.5% and 27.5%, and those with grade Ⅳ and Ⅴ account for 60% in all samples. The relationship between soil nutrients and land types indicates that the nutrients of farmland are relatively good, with 41.7% of soil samples with the nutrient grade Ⅳ and Ⅴ. The nutrients of saline-alkali land and sandy land are the worst, with 100% of soil samples with the nutrient grade Ⅳ and Ⅴ. And the ratios of soil samples grade Ⅳ and Ⅴ in grassland and wasteland are respectively 62.5 % and 54.55%. Generally speaking, the soil nutrients status in Da'an City is poor, 60% of soil samples are in poor and extremely poor conditions, indicating that the soil has been severely eroded. Being a relatively superior evaluation method with more accurate resuits and spatial distribution consistency, matter-element analysis is more suitable for regional soil nutrient evaluation than previous models.     

冤家和解

6月20日,栾川县国土资源局副局长李苏毅带领有关科室负责人,到庙子乡庄子村调研时,得知村委需配备一批办公设施但资金短缺时,当即捐助现金2000元,这是局年初出资3万元支持村委办公楼建设后,为扶贫村扶贫解困办的又一件实事。     

洛阳市:飓风行动 彻底整改

2008年11月23日,一场声势浩大的集中拆除违法建（构）筑物的“飓风行动”在洛阳全面展开。截至12月25日,洛阳市135宗违法用地全部整改到位,违法建筑拆除率100％。这次“飓风行动”共拆除违法建筑物296714平方米,复耕土地420余亩,收取罚没款1984．03万元,移送司法机关21人,追究刑事责任4人,受党政纪处分21人,其中处级干部1人,科级干部20人。     

Elastic-plastic analysis for pile-anchor supporting system of deep foundation pit

By using numerical analysis methods to simulate the deep excavation, a lot of analyses are established on the basis of two-dimensional plane strain, ignoring the fact that foundation pit possesses three dimensions. For soil constitutive relation, people always take linear and nonlinear model, without considering the plastic behavior of soil. Using plastic-elastic hardening model to simulate constitutive relation of soil characteristics, the authors carried out mechanical analysis for pit excavation and support. The results show that the analysis for the stress state of pile anchor system is an effective way which provides theoretical basis for calculation of soil displacement.