Effect of nitrogen to phosphorus ratios on cell proliferation in marine micro algae

The ratio of nitrogen/phosphorus (N/P) is known to affect cell proliferation of some marine micro algae. We evaluated the effect of N/P ratios on the proliferation and succession of phytoplankton using five marine micro algae species. We used two sources of nitrogen, NH4Cl (N1) and urea (N2), and a single source of phosphorous, NaH2PO4(P). The optimal N/P ratio that differed among the five species was affected by the source of nitrogen, being as follows (N1/P, N2/P in order): Thalassiosira sp. (30/1, 20/1),...     

微型钢管灌注桩基础托换技术

为解决既有建筑基础加固工程中有限的施工空间和成本控制问题,研究采用了微型钢管灌注桩基础托换技术,实践表明,该技术是一种实用可行的施工方法。介绍了微型钢管灌注桩基础托换技术的机理及施工工艺,并通过工程实例阐明了该技术的可行性和有效性。     

Performance of A Combination Process of UV/H2O2/Micro‐Aeration for Oxidation of Dichloroacetic Acid in Drinking Water

The decomposition of dichloroacetic acid (DCAA) in water using a UV/H₂O₂/micro‐aeration process was investigated in this paper. DCAA cannot be removed by UV radiation, H₂O₂ oxidation or micro‐aeration alone, while UV/H₂O₂/micro‐aeration combination processes have proved effective and can degrade this compound completely. With initial concentrations of about 110 μg/L, more than 95.1% of DCAA can be removed in 180 min under UV intensity of 1048.7 μW/cm², H₂O₂ dosage of 30 mg/L and micro‐aeration flow rate of 2 L/min. However, more than 30 μg/L of DCAA was left after 180 min by UV/H₂O₂ combination process without micro‐aeration with the same UV intensity and H₂O₂ dosage. The effects of applied UV radiation intensity, H₂O₂ dose, initial DCAA concentration and pH on the degradation of DCAA have been examined in this study. Degradation mechanisms of DCAA with hydroxyl radical oxidation have been discussed. The removal rate of DCAA was sensitive to operational parameters. There was a linear relationship between rate constant k and UV intensity and initial H₂O₂ concentration, which indicated that a higher removal capacity can be achieved by improvement of both factors. A newly found nitrogenous disinfection by‐product (N‐DBP)‐DCAcAm, which has the potential to form DCAA, was easier to remove than DCAA by UV/H₂O₂ and UV/H₂O₂/micro‐aeration processes. Finally, a preliminary cost comparison revealed that the UV/H₂O₂/micro‐aeration process was more cost‐effective than the UV/H₂O₂ process in the removal of DCAA from drinking water.     

结构性粘土研究进展

通过对结构性粘土的研究,可以掌握天然土受荷过程中的变形破坏过程,从而为考虑土结构性的结构物的设计、地基加固等提供依据。近年来随着高、深和大型建筑的兴建,结构性粘土的研究变得尤为重要。从结构性粘土的微观变形机理、结构性土样的制备、土工特性和数学模型等几个方面,介绍了国内外学者的研究进展,认为进行原位测试、结构性土样的制备及细观结构参数的量测方法、考虑细观结构的数值方法和建立考虑微观变形机理的宏观本构模型是进行结构性土研究的发展方向。     

松辽盆地徐家围子断陷深层天然气同位素倒转现象研究

天然气的同位素组成受源岩有机质类型、热演化程度和成藏后的次生变化等多种因素的影响, 其单体烃同位素分布特征是区分各种因素影响程度的地球化学指纹.天然气单体烃同位素通常有随碳数增加而变重的趋势, 而徐家围子深层天然气单体烃同位素倒转现象却比较普遍, 高地温和细菌氧化对于造成该区同位素倒转的可能性不大, 浅层油型气或无机气的混合作用没有充分的地质证据, 同层有机质中不同类型气的混合和盖层微渗漏造成的蒸发分馏作用可能是导致徐家围子断陷深层天然气同位素倒转的主要原因.      

微细浸染型金矿深源矿质和流体地球化学示踪研究

在宏观和微观地质特征研究基础上,运用硅同位素动力学分馏原理,结合硅质阴极发光分析,论证了微细浸染型金矿的成矿硅质、矿质和流体主要直接来源于上地幔分异或深部循环的超临界流体,并认为这种深部因素可能对形成大型和超大型矿床发挥了重要作用.这对该类型金矿的成因研究及找矿开辟了新的思路.     

天祝-古浪5.4级地震前震源区应力场的短临变化特征

利用矩张量反演方法反演了 1996年 6月 1日天祝 -古浪 5 .4级地震序列的震源机制 ,并与该区小震综合断层面解进行了比较。在此基础上讨论了该地震前后震源区应力场的变化特征。     

下击暴流实例分析

通过实地灾情调查,本文提供了一个证据较为充分、说服力较强的下击暴流实例,加深了人们对下击暴流的感性认识。实践证明,在观测密度(时间和空间上)远不能满足中小尺度分析要求、探测手段受到很大限制的情况下,用实地灾情调查和地面拍照的办法进行下击暴流这类中小尺度系统的分析是可行的。     

An Economical Consistent Dissipation Operator and Its Applications to the Improvement of AGCM

ＡｎＥｃｏｎｏｍｉｃａｌＣｏｎｓｉｓｔｅｎｔＤｉｓｉｐａｔｉｏｎＯｐｅｒａｔｏｒａｎｄＩｔｓＡｐｐｌｉｃａｔｉｏｎｓｔｏｔｈｅＩｍｐｒｏｖｅｍｅｎｔｏｆＡＧＣＭ①ＷａｎｇＢｉｎ（王斌）ａｎｄＪｉＺｈｏｎｇｚｈｅｎ（季仲贞）ＬＡＳＧ，Ｉｎｓｔｉｔｕｔｅ...     

切变线降水系统微物理特征及隆水机制个例分析

利用机载云粒子探测系统(PMS).对2004年7月1日影响吉林省的一次切变线降水过程进行了探测飞行,利用所获取的宏微观资料对此次降水过程的微物理结构、降水机制进行综合分析.结果表明:此次切变线降水云系主要由高层云、雨层云、碎云构成,高层云和雨层云中间夹有1100m左右的无云区;3类云中平均云滴浓度、平均云滴直径各不相同;云水含量随高度分布不均匀,云的不同部位云水含量起伏较大;冰晶浓度平均为17.3个/L;此次探测的降水云系符合Bergeron提出的催化云一供水云相互作用导致降水的概念.根据云图及其他探测资料综合分析,冰晶主要产生于高层云上部或卷层云的冰晶播撒,供水云为高层云中下部和雨层云.