nitial Potential" Effect on the Dissociative Adsorption of Methanol on A Roughened Platinum Electrode in Acidic Solution

The research of electrocatalytic oxidation of small organic molecules such as methanol, formaldehyde and formic acid has been fascinating electrochemists for more than thirty years, owing to its significance in energy conversion and reaction mechanisms. The surface adsorbed species involved in these electrocatalytic reactions, especially reactive and poisoning intermediates, have been investigated by electrochemical, spectroscopic and other physicochemical methods1. However, Raman spectrosco…     

减阻工况下壁面周期扰动对湍流边界层多尺度的影响

通过在平板壁面施加不同频率振幅的压电陶瓷振子周期性扰动,进行了湍流边界层主动控制减阻的实验研究.在压电陶瓷振子最大减阻工况下(80 V和160Hz),使用单丝边界层探针对压电振子自由端下游2mm处进行测量,得到不同法向位置流向速度信号的时间序列.通过对比施加控制前后的多尺度分析,发现压电振子产生的扰动只对近壁区产生影响,使得近壁区大尺度脉动降低,小尺度脉动强度增大,而对边界层的外区则基本没有影响.进一步对大尺度和小尺度的脉动信号进行条件平均,发现压电振子产生的扰动对小尺度脉动的影响在时间相位上并不均匀,小尺度脉动强度在大尺度脉动为正时比在大尺度脉动为负时具有更明显的增加.这表明壁面周期扰动主要通过使大尺度高速扫掠流体破碎为小尺度结构,来影响相应的高壁面摩擦事件,从而达到减阻效果.      

Crystal Structure of Tris(2,2'-bipyridine)nickel(II) Tetrachlorozincate

1　INTRODUCTIONThe coordination chemistry oftransition metalcomplexeshasbecomeofremark able interestin recentyears.Sotoftetal.reported the structure of Ni( CH3CN) 6·Zn Cl4 〔1〕.Recently,Shyu etal.reported the structure of〔 Ni( bipy) 3〕〔 Fe( CN) 5 ( NO)〕· 3 H2 O〔2〕.Herein we reportthe structure oftitle complex〔 Ni( bipy) 3〕〔 Zn Cl4 〕 which issimilarto theformertwo complexes.Itisvery interesting to synthesizebimetallic compoundsfor both theoreticalstudy and practicalapp…     

壁湍流多尺度湍涡结构推广的自相似标度律

在水槽中测量了中等雷诺数下平板湍流边界层中的瞬时流向速度的时间序列,验证了Benzi提出的推广的自相似标度律,用子波变换将壁湍流脉动速度分解为多尺度湍涡结构的速度,研究了每一个尺度的湍涡速度结构函数的推广的自相似标度律。主要结论如下:湍流的统计性质是自相似的,这不仅适用于充分发展湍流,而且适用于中等雷诺数和低雷诺数湍流,而且具有相同的标度指数;推广的自相似标度律的适用的尺度范围远远大于惯性子区的范围,可以一直延伸至耗散区的尺度范围;推广的自相似标度律不仅适用于均匀各向同性湍流,也适用于剪切湍流如边界层湍流。     

三甲川菁染料敏化TiO2纳米 结构电极的光电化学

The photoelectrochemical behaviors of the TiO₂ nanostructured porous film sensitized by cyanine dye were investigated in this paper.The results showed that the excitaed state level matched the conduction band edge of TiO₂ nanoparticle.Therefore the sensitization of the dye can increase the photocurrent intensity of the TiO₂ nanostructured electrode obviously and results in a red-shift of optical absorption from the ultra-violet region to the visible.As a result,the light-to-electricity conversion efficiency was improved evidently,the maximum value of IPCE has reached 12.1%.     

Synthesis and Crystal Structure of Dicesium trans Dicarbonatotetraaquomagnesium, Cs_2[Mg(CO_3)_2(H_2O)_4]

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Synthesis and Crystal Structure of α-( N-Protected a mino)β- lactam Derivative of 1 ,5-Benzothiazepine

１　ＩＮＴＲＯＤＵＣＴＩＯＮＲｅｃｅｎｔｌｙ,ａｎｕｍｂｅｒｏｆｄｅｒｉｖａｔｉｖｅｓｏｆｂｅｎｚｏｔｈｉａｚｅｐｉｎｅｈａｖｅｂｅｅｎｐｒｅｐａｒｅｄａｎｄｓｔｕｄｉｅｄｆｏｒｔｈｅｉｒｐｈａｒｍａｃｏｌｏｇｉｃａｌａｃｔｉｖｉｔｉｅｓ〔１５〕．Ｉｎｏｕｒｐｒｅｖｉｏｕｓｗｏｒｋ,ｗｅｈａｖｅｉｎｃｏｒｐｏｒａｔｅｄｔｈｅβｌａｃｔａｍｒｉｎｇｉｎｔｏ１,５ｂｅｎｚｏｔｈｉａｚｅｐｉｎｅｂｙｒｅａｃｔｉｏｎｏｆ１,５ｂｅｎｚｏｔｈｉａｚｅｐｉｎｅｗｉｔｈｓｏｍｅａｃｙｌｃｈｌｏｒｉｄ…     

Novel Silicon Nanotubes

The preparation of silicon nanotubes is a subject of great importance for both the theoretical and experimental work in the nanotube research field since it could lead to a wealth of new physics and chemistry because of the unique properties of silicon as compared with its carbon analogue. Some structures of nanoscale silicon and silicon composites, such as silicon nanowire1, silicon nano-clusters2 and SiC nanorods3 have been discovered and investigated. The silicon nanotubes, however, have …     

Determination the Hydrogen Stored in Carbon Nanotubes by NO Titration Method

With the diminution of fossil fuel resources and the increase in pollution, energy and environment have become a public concern. Mankind is in need of a new but clean energy resource. The use of hydrogen appears to be the answer. One of the technical challenges in hydrogen utilization is H2-storage. At present, materials for storing hydrogen are alloys such as LaNi5 and FeTi; the storage capacity is around 1.4 wt%, too low for practical application. Another problem with these alloys is…     

Ethylene Oligomerization by (dppe)MCl_2 [M = Fe(II), Co(II),Ni(II)] Complexes/EAO

Transition-metal-catalyzed oligomerzation of ethylene is an important process to provide a-olefins in the C6~C20 range. In recent years, the catalytic behavior of late transition metal complexes containing bi- and tri-dentate ligands for oligomerization of ethylene to a-olefins has attracted much attention. When oligomerization of ethylene catalyzed by nickel diimine and Fe(II), Co(II) 2,6-bis(imino)pyridine catalysts, the oligomers with high average molecular weight were obtained1-5. Eth…