有机化合物结构与生物降解性的定量关系研究

采用量子化学MOPAC -AM 1法计算了 2 3种有机物的生成热ΔHf、分子最高占有轨道能EHOMO、分子最低空轨道能ELUMO、分子总表面积STSA及偶极矩 μ .结合辛醇 -水分配系数logKOW对生物降解速率常数lnK进行了定量结构 -生物降解性关系 (QSBR)分析 .对 1 1种取代苯和 1 2种脂肪族化合物分别做出如下多元回归方程 :-lnK =1 .82 + 0 .0 1 53STSA+ 1 2 4× 1 0 - 3ΔHf+ 0 .0 981 μ ,n =1 1 ,R2 =0 .73 9,s=0 .1 45,F =6.62 ,p =0 .0 1 9;-lnK =3 .0 6+ 0 .0 2 64STSA+ 3 0 8× 1 0 - 3ΔHf-0 .1 1 9μ ,n =1 2 ,R2 =0 .867,s=0 .2 1 2 ,F =1 7.3 8,p =0 .0 0 1 .应用所得QSBR模式预测了 2 3种有机物的生物降解性 ,方程对大多数化合物拟和很好 .结果表明 ,所研究有机物的生物降解性主要与分子大小、稳定性及分子极性有关 ,化合物与酶的活性点结合或反应是影响微生物降解的主要因素 .     

苯甲酸、苯酚及苯胺类在自然水体中的生物降解速率

以天然水中的混合细菌为降解微生物,通过实验测定,得到取代苯甲酸、苯酚及苯胺类化合物生化需氧量随时间的变化曲线,数据符合生物降解一级反应动力学方程.采用基团贡献法进行化合物的结构与生物降解速率常数之间的定量关系研究,各基团对生物降解性的贡献依次为:苯基、羧基、甲氧基/甲基、羟基、氨基、硝基.所得线性预测模型稳健性和预测性很好,大多数化合物的预测误差在±0 1之间,预测值与实测值的相关系数达0 929.     

邻苯二甲酸酯分子结构与厌氧生物降解相关性研究

以产气量为指标测试了10种邻苯二甲酸酯的厌氧生物降解性状,发现随分子结构的变化,其厌氧终极降解速率和降解半衰期表现出较大差异,厌氧生物降解难易程度依次为：DMP：DEP〉DnPP〉DnBP〉DnAP〉〉DiHP〈DnOP=DINP〉DUP;将分子结构参数与降解速率、半衰期用SPSS进行多元回归分析表明邻苯二甲酸酯的分子结构是决定其厌氧生物降解性的关键因素,高分子量的化合物不利于厌氧生物降解．研究结果对其厌氧生物处理、生物修复具有一定的理论指导意义．     

普通小球藻对DEHP的富集和降解动力学

微藻具有富集和降解有机污染物的能力.邻苯二甲酸二异辛酯(DEHP)是最重要且用量最大的一种酞酸酯类化合物,为此选择普通小球藻,研究它对DEHP的富集和降解动力学.实验在250mL三角瓶中进行,温度为(25±1)℃,光强为(4000±100)lx,DEHP的初始浓度约为0.4mg/L.实验结果表明,普通小球藻对DEHP有较明显的富集与生物降解作用,8d的藻富集率为28.100,藻降解率为25.700,藻对DEHP富集量在0.5h达最大为107.4mg/g(干重),富集系数在6h达最大为3.67×105.藻对DEHP的降解符合一级动力学过程,降解速率常数为0.0021h-1.     

含盐条件下偶氮染料兼厌氧性生物的降解性能

研究活性染料与不同浓度葡萄糖共基质条件下的兼厌氧性生物降解性能和K-2BP在不同盐浓度条件下的兼厌氧性生物降解性能.选择K-2BP作为目标污染物进行静态反应器生物降解实验.结果表明,兼厌氧性微生物在只有K-2BP作为基质时对染料的降解率较低,葡萄糖存在时,能提高兼厌氧性生物对染料的降解能力;葡萄糖为800mg/L时6h染料降解率为64.1%,而葡萄糖浓度为1 000mg/L时,不利于染料降解,6h染料降解率为46%,与不投加葡萄糖情况的降解率接近.葡萄糖浓度为800mg/L,盐浓度分别为2g/L,5g/L,10g/L和20g/L,其一级降解动力常数分别为0.105 78mg/L.h,0.049 47mg/L.h,0.028 69mg/L.h,0.022 75mg/L.h;半衰期分别为6.99h,14.15h,22.55h,30.21h.随盐浓度梯度升高,染料的兼厌氧性降解动力学常数逐渐降低,高盐浓度会抑制兼厌氧性微生物对染料的降解.     

Ni[(C_4H_9O)_2PS_2]_2与氮碱加合反应的研究

用光谱法研究了Ni[(C4H9O) 2 PS2 ]2 与咪唑、邻菲咯啉在乙醇溶液中的加合反应 ,测定了反应的平衡常数lgβn 及加合分子数n ,在 32℃时 ,与咪唑反应lgK1 =2 .85± 0 .0 7,lgβ2 =5.69± 0 .0 9;与邻菲咯啉反应lgβ2 =7.68± 0 .1 1 比较了咪唑与吡啶类化合物的平衡常数值的大小 ,得到了平衡常数值不仅与氮碱的 pKa值有关 ,而且和其空间效应有关的重要结论     

三氮烯类化合物作为酸碱指示剂的研究及应用

本文报道了三氮烯类化合物作为酸碱指示剂的研究及应用.以我们新近合成的此类试剂之一——2-氯一4一硝基苯基重氮氨基偶氮苯为研究主要对象,分别讨论了有无表面活性剂存在、以及不同类型表面活性剂存在下,试剂的离解常数及变色区域.在TritonX-100存在下,其试剂的pKa=9.25±0.01,变色区域为pH8.40(黄)～10.0(紫);在CTMAB存在下,pKa=7.35士0.03,变色区域pH6.85～7.90;在混合表面活性剂TritonX-100-CTMAB存在下,pKa=8.20±0.05,变色域pH7.45～9.00(黄～紫).特别是在阳离子表面活性剂存在下,滴定终点颜色变化十分敏锐清晰,是一种优于酚酞和甲基橙的指示剂.最后并对此类试剂与表面活性剂的相互作用作了简单探讨.     

苯砜基羧酸酯类化合物急性毒性的QSAR研究

采用密度泛函理论方法,在B3LYP/6-31G(d)水平下,计算了35种苯砜基羧酸酯化合物的量子化学参数.采用统计学软件Statistic 6.0进行多元线性回归,得到描述此类化合物对发光菌急性毒性的预测模型-lgEC50=-0.01×P+1.92×q1-5.63×q10-0.087×μ+2.34,模型的相关性分析如下R=0.92,r2adj=0.82,F=40.96,q2=0.837.得到以下结论苯砜基羧酸酯类化合物急性毒性随着亲水性的增强而减弱;分子越大,毒性越小;取代基的电负性越大,毒性越小.该研究为探讨化合物急性毒性的机理起到借鉴作用.     

抗生素磺胺甲恶唑在模拟太阳光下的光解

为了弄清磺胺类药物在水体中的环境行为,以磺胺甲恶唑为模型化合物,研究其在模拟太阳光下的光解特征,考察不同因素对降解行为的影响。实验结果表明,磺胺甲恶唑在模拟太阳光下发生光解,光解速率随着质量浓度的升高而下降,最高降解速率达到0.36 h?1;同时,在酸性条件下(尤其p H值小于5),其降解半衰期显著低于碱性条件下(p H值为8)的降解半衰期,最小为2.10 h;并且在不同质量浓度NO3?下磺胺甲恶唑的降解速率会发生变化,低质量浓度促进降解,而高质量浓度抑制降解。     

氟尿嘧啶植剂皮下植入的药代动力学

目的:研究5-氟尿嘧啶植入剂(5-Fuimplant5Ful)犬皮下植入的药代动力学。方法:用高效液相色谱法(HPLC)测定血浆5-Fu浓度。结果:犬皮下植入5-FuI20mg/kg后血药浓度—时间变化过程符合具有缓释的一房室模型,缓释半衰期T0.5r=52.7±10.9h,在体内维持有效浓度(≥1ug/mL)时间长达216～240h。结论:5-FuI皮下植入确具缓释作用和维持有效浓度时间长的优点。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that