计算机模拟研究UO2+2在人体细胞液的形态分布

建立了由多种金属离子和小分子配体组成的多相细胞液热力学平衡模型.模拟研究了UO2 2在组织液和细胞液的形态分布及CO2-3、氨三乙酸（NTA）和乙二胺四乙酸（EDTA）浓度对细胞液中UO2 2形态分布的影响.在组织液中,正常生理pH下,当各形态UO2 2总摩尔浓度 [U]= 1.0×10-6 mol/L 或[U]=1.0×10-3 mol/L时,UO2 2均主要以[UO2(CO3)3]4-和[UO2(CO3)2]2-形态存在.在细胞液中,当[U]=1.0×10-6 mol/L时,UO2 2主要以[UO2(CO3)3]4-和[UO2(CO3)2]2-存在;当[U]=1.0×10-3 mol/L,pH为6.0～6.8时,细胞液中存在大量的固相(UO2)3(PO4)2·4H2O,当pH为6.8～7.4时,UO2 2主要以[UO2(CO3)3]4-、[UO2(CO3)2]2-和[(UO2)2CO3(OH)3]-存在.细胞液中(UO2)3(PO4)2·4H2O含量随[U]升高而增加.通过调节细胞液pH和增加细胞液CO2-3浓度均能降低其固相UO2 2配合物含量.在细胞液中增加NTA会增加(UO2)3(PO4)2·4H2O含量,当添加EDTA时会显著降低(UO2)3(PO4)2·4H2O含量.     

高矿化度矿井水饮用处理新方案探讨

在分析常规高矿化度矿井水处理方案的基础上提出分质供水和终端除盐两种新方案,以实例进行了经济分析,认为“分质供水,建立矿区小型脱盐段质饮用水站,桶装供应”经济可行,这在其它特殊矿井水饮用处理中同样具有参考价值。     

几种新式太阳能光催化反应器的探讨

本文综述了几种新式的太阳能光催化反应器 ,对其结构和处理效果进行了比较 ,并对该法处理水的经济性进行简单的概述 ,指出光催化法是一种可以充分利用太阳能、具有很大发展潜力的水处理方法     

用灰色关联法分析森林生态系统植被状况对地表径流系数的影响

运用灰色关联法对南亚热带鹤山丘陵试验站４种森林生态系统植被状况影响地表径流系数进行了定量分析,结果表明：对于本文所选取的植被状况参数对地表径流系数影响的大小顺序是：枯落叶层厚度〉草本层盖度〉灌木层盖度〉林分高;４种森林生态系统的植被状况对地表径流系数的影响,马占相思林最大,平权关联度与非平权灰关联度分别为０．７８２和０．７６６;林果苗系统最小,平权关联度与非平权灰关联度分别为０．５３２和０．５３５     

Monitoring nitrogen deposition in typical forest ecosystems along a large transect in China

The nitrogen (N) deposition fluxes were investigated in eight typical forest ecosystems along the North–South Transect of Eastern China (NSTEC; based on the ChinaFLUX network) by ion-exchange resin (IER) columns from May 2008 to April 2009. Our results demonstrated that the method of IER columns was both labor cost saving and reliable for measuring dissolved inorganic nitrogen (DIN) deposition at the remote forest stations. The deposition of DIN in the throughfall ranged from 1.3 to 29.5 kg N ha^?1 a^?1, increasing from north to south along NSTEC. The relatively high average ratio of ammonium to nitrate in deposition (1.83) indicated that the N deposition along the NSTEC in China mostly originated in farming and animal husbandry rather than in industry and vehicle activities. For seasonal variability, the DIN deposition showed a single peak in the growing season in the northern part of NSTEC, while, in the southern part, it exhibited double-peaks in the early spring and the mid-summer, respectively. On the annual scale, the DIN deposition variations of the eight sites could be mainly explained by precipitation and the distances from forest stations to provincial capital cities.     

Estimating nitrate leaching with a transfer function model incorporating net mineralization and uptake of nitrogen

Because of the complex interaction of chemical and biological processes of nitrogen (N) in soils, it is difficult to estimate the leaching of nitrate with various N transformations in porous media. In this study, a transfer function model was developed to simulate the outflow concentration of nitrate in soils during the growth of winter wheat (Triticum aestivum L.), taking into account the main N transformations using source and sink terms. The source and sink terms were treated as inputs to the solute transport volume and incorporated into the transfer function model to characterize their effects on nitrate concentration in the outflow. A field experiment was conducted in three nonweighing lysimeters for 181 d. Nitrate concentrations were measured along the 2-m soil profile of each lysimeter at different times. Comparison between the experimental data and simulated results with the transfer function showed that the model provided reasonable prediction of the nitrate leaching process as well as the total amount leached. Results also indicated that considering the N transformations in the transfer function significantly increased the estimation accuracy. The relative errors of total amount leached were < 7% with the N transformations included, but up to 17% without including the transformation processes.     

森林地表火蔓延边界预测预报图形显示系统

地表火蔓延状况的预测预报是森林防火灭火工作中的一项重要技术。目前，国外在预测火场扩展边界的形状及分布时采用了火场椭圆面假设，当可燃物、地形或气象条件复杂变化时，预测结果偏差较大。本文从地表火蔓延的本质入手，建立起确定复杂地形、气象条件和可燃物分布情形下的火蔓延边界的数学模型，并借助于现代软件编制技术，成功地编制出预测预报地表火蔓延边界的图形显示系统，率先实现了对任意情形下火蔓延边界的合理、准确的估算。     

膨润土对土壤腐殖质特性的影响

砂质土壤腐殖质含量低,影响了土壤肥力.文章通过田间条件下砂滤管试验,利用膨润土的吸附和粘结功能,研究了膨润土不同用量对土壤腐殖质特性的影响.结果表明:膨润土在促进松结态腐殖质分解、加速紧结态腐殖质合成方面发挥了重要作用,有利于增加土壤系统的内稳性.施用膨润土促进了紧结态和稳结态腐殖质中HA的积累,提高了HA/FA比.胡敏酸红外吸收光谱表明,膨润土能使其脂肪族物质增多、芳化度降低.膨润土具有提高土壤腐殖质含量,改善土壤腐殖质特性,从而提高了土壤肥力.     

鼠尾藻提取物对亚历山大藻的化感效应

研究不同浓度的鼠尾藻组织蒸馏水及4种不同极性有机溶剂(甲醇、丙酮、乙醚、氯仿)提取物对亚历山大藻的生长抑制作用.结果表明:鼠尾藻组织甲醇提取物对亚历山大藻的生长抑制活性最强,大于3×10-8 mg kg-1浓度作用下亚历山大藻在1 d内完全死亡;鼠尾藻组织蒸馏水抽提物与对照组相比在各个浓度时均能显著抑制亚历山大藻的生长,但即使在最高浓度1.6×10-6mg kg-1下亦对其无致死效应;其他3种有机溶剂提取物对亚历山大藻的生长无明显影响.表明鼠尾藻组织中含有的对亚历山大藻具有抑制作用的活性物质具有较高的极性.对鼠尾藻甲醇提取物进行液液萃取,将其分离为石油醚相、乙酸乙酯相、正丁醇相和蒸馏水相,并对亚历山大藻进行生物活性检测.结果发现,石油醚相和乙酸乙酯相具有较强的杀藻活性,表明脂肪酸可能是鼠尾藻组织内抑制亚历山大藻生长的克生物质的重要组成成分之一.图3参36