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1.
储氢特性的模拟可以加深对现有储氢系统的认识,促进新材料的设计,并预测新材料的性能;模拟可以提供定量数据,作为一些困难及昂贵实验的替代选择。采用巨正则蒙特卡罗方法模拟了氢气在沸石中的吸附行为,并采用SF微孔分析方法,分析了沸石结构对储氢量大小的影响,总结了影响储氢量大小的物理因素。  相似文献   

2.
采用分子动力学(MD)方法对3种含有缺陷的椅式(5,5)、椅式(6,6)和齿式(10,0)碳纳米管储氢能力进行了模拟研究,考查了缺陷大小、缺陷位置、碳纳米管直径和螺旋性以及温度对碳纳米管储氢性能的影响.模拟结果表明;碳纳米管在80K时的储氢能力明显高于298K时的储氢能力;在相同条件下,直径较大的碳纳米管储氢性能优于直径较小的;当碳纳米管上的缺陷孔较小时,碳纳米管在室温下即可达到较高的储氢量,且缺陷位于碳纳米管端部时的储氢量大于缺陷位于管壁时的储氢量,而碳纳米管的螺旋性对储氢量影响较小;当缺陷孔的尺寸变大时,碳纳米管的储氢量明显下降,与此同时,碳纳米管的螺旋性对碳纳米管储氢量的影响趋于明显,而缺陷所在位置对储氢量的影响则相应减弱.  相似文献   

3.
采用蒙特卡罗方法模拟常温、中等压强下单壁氮化硼纳米管的储氢,重点研究了单壁氮化硼纳米管的管径、管长和手性以及压强对其物理吸附储氢的影响.与单壁碳纳米管的物理吸附储氢相比较,氮化硼纳米管的储氢性能明显优于碳纳米管.计算结果显示,在常温、中等压强下单壁氮化硼纳米管的物理吸附储氢量(质量百分数)可以达到美国能源部提出的商业标准.  相似文献   

4.
采用分子动力学方法,模拟了常温和不同压强下,氢在不同管径和管间距的单壁碳纳米管阵列(SWCNTA—S ingle-walled Carbon Nanotube Arrays)中的物理吸附过程.重点研究了压强、管径和管间距对SWCNTA(管内和管间隙)物理吸附储氢的影响.发现氢分子主要储存在SWCNTA的管壁附近,适当地增大管径和管间距可有效增加SWCNTA的物理吸附储氢量,使其在常温下具有较高的储氢能力,并给出了相应的理论解释.计算结果表明,在常温和中等压强下,SWCNTA的物理吸附总储氢量(重量百分比)可达4.2%,从而为同等条件下SWCNTA具有较高储氢能力的实验结果提供了直接的理论支持.  相似文献   

5.
通过实验考察了沸石粒径、投加量、废水pH和吸附时间对NaCl改性沸石去除废水中氨氮的影响,结合单因子实验和正交实验获得优化条件组合,并在优化组合条件下,将NaCl改性沸石去除氨氮效果在实际废水中进行验证.结果表明,粒径越小越利于NaCl改性沸石对废水中氨氮的去除,而投加量、废水pH和吸附时间亦对改性沸石去除氨氮产生影响,通过正交优化实验分析得出,最主要影响因素为沸石投加量,结合单因子实验,筛选出改性沸石去除废水中氨氮的最佳工艺组合条件为沸石粒径60目、沸石投加量70g/L、废水pH=6、吸附时间1h,废水中氨氮去除率达到90.5%.在最佳工艺组合条件下,NaCl改性沸石对生活污水、养猪废水和化工工业废水中氨氮的去除率分别为91.67%、91.65%和89.31%,与在模拟废水中的去除率基本一致.这为改性沸石的进一步实际应用奠定了基础.  相似文献   

6.
采用巨正则蒙特卡罗方法,研究了锂掺杂对单壁氮化硼纳米管阵列(SWBNNTA-SingleWalled Boron Nitride Nanotube Array)物理吸附储氢的影响.揭示了锂掺杂是提高SWBNNTA储氢能力的有效手段,并给出了最佳的掺杂方案.计算结果表明,选择最佳的掺杂方案,并合理控制SWBNNTA的结构与尺寸,可使锂掺杂SWBNNTA在常温、中等压强下的物理吸附储氢量达到和超过美国能源部提出的2015年研究目标.  相似文献   

7.
对计算化学势的Widom测试粒子方法进行了改进.采用改进后的Widom测试粒子方法和周期边界流体系统的压力算法,研究开放系统的化学势随压强的变化,给出了具体的函数关系,并证明了其正确性.在此基础上,通过巨正则蒙特卡罗模拟,仔细地分析了化学势对模拟计算单壁碳纳米管储氢的影响.计算结果表明,化学势的偏差对模拟计算单壁碳纳米管储氢有着非常显著的影响.  相似文献   

8.
为寻求具有直接吸附缓释效应的环境材料,首先通过对比三种沸石对氨氮的吸附动力学行为,研究沸石吸附解吸机理,然后应用等温吸附研究沸石等温吸附特征,再结合电镜扫描、比表面积和孔径分析,采用动力吸附和等温吸附实验,研究人造沸石吸附氨氮机理以及沸石结构对其吸附性能的影响.结果表明,沸石对NH_4~+的吸附动力学行为符合伪二级动力学方程,NH_4~+浓度为400 mg·L~(-1)时,三种沸石吸附量相差倍数最大,AZ吸附量分别是MO和CL的2.83倍和4.07倍;Freundlich方程能很好地模拟人造沸石对氨氮的吸附过程,吸附强度值大于天然沸石.  相似文献   

9.
研究了建筑外墙隔热保温涂料的制备及隔热性能的测试,采用太阳热反射模拟试验方法,研究不同功能填料(粉煤灰漂珠、硅藻土以及沸石分子筛)的添加量及涂膜厚度对涂料隔热性能的影响,并通过对功能填料进行SEM表征及导热系数的测定,分析比较以上几种功能填料的隔热效果。结果表明:制备的涂料均符合国家标准;涂层厚度对涂料的隔热性能影响相对较小;粉煤灰漂珠、硅藻土和沸石分子筛对涂料的隔热性能都有一定影响,其中沸石分子筛添加量为9%的隔热效果最好,其平衡温度比空白降低了12℃。  相似文献   

10.
两种沸石吸附废水中磷污染物的研究   总被引:1,自引:0,他引:1  
采用人造沸石和4A沸石对含磷50 mg·L-1模拟废水进行吸附实验,研究了沸石用量、含磷浓度、吸附时间、反应温度和pH值对两种沸石吸附性能的影响.结果表明,室温,pH=2~3,P2.5 mg/g(沸石),吸附100 min的条件下,两种沸石对磷的去除率均在90%以上,4A沸石对磷的吸附效果优于人造沸石.  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
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.  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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-  相似文献   

19.
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-  相似文献   

20.
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  相似文献   

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