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101.
Rebecca L. Agapov Jonathan B. Boreyko Dayrl P. Briggs Bernadeta R. Srijanto Scott T. Retterer C. Patrick Collier Nickolay V. Lavrik 《Advanced Materials Interfaces》2014,1(9)
Directional control of droplet motion at room temperature is of interest for applications such as microfluidic devices, self‐cleaning coatings, and directional adhesives. Here, arrays of tilted pillars ranging in height from the nanoscale to the microscale are used as structural ratchets to directionally transport water at room temperature. Water droplets deposited onto vibrating chips with a nanostructured ratchet move preferentially in the direction of the feature tilt while the opposite directionality is observed in the case of microstructured ratchets. This remarkable switch in directionality is consistent with changes in the contact angle hysteresis. To glean further insights into the length scale dependent asymmetric contact angle hysteresis, the contact lines formed by a nonvolatile room temperature ionic liquid placed onto the tilted pillar arrays were visualized and analyzed in situ in a scanning electron microscope. The ability to tune droplet directionality by merely changing the length scale of surface features all etched at the same tilt angle would be a versatile tool for manipulating multiphase flows and for selecting droplet directionality in other lap‐on‐chip applications. 相似文献
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103.
Qing Tian Pengcheng Liu Yuwei Jiao Aifang Bie Jing Xia Baozhu Li Yang Liu 《International Journal of Hydrogen Energy》2017,42(29):18146-18155
The paper developed a new constant-rate solution for non-planar asymmetric fracture connected to a vertical wellbore in hydrocarbon reservoirs. The non-planar asymmetric fracture has been modeled by combination of two unequal length wings with varied intersection angles. The type curves were drawn in the case of varied fracture conductivities, non-planar angles, and asymmetric factors. The results indicated that fracture conductivity, non-planar angle, and asymmetric factor have coefficient effects on the pressure response, which makes the dimensionless wellbore pressure and pressure derivative curves deviate from the conventional type curves of vertical fractured wells. The dimensionless wellbore pressure and pressure derivative curves are divided into five flow periods. The non-planar angle and asymmetry factor have their unique influences on the shape of type curves during different periods under the different fracture conductivities. The termination of bilinear flow and formation linear flow happened increasingly early with the decrease of non-planar angle or the increase of asymmetry factor. As the fracture conductivity increases, the effect of non-planar angle on the curves moves from the early flow period to the late flow period while the trend of effect of asymmetric factor is quite opposite. The new method lays the foundation of the pressure analysis of the complicated fracture system in developing hydrocarbon reservoirs. 相似文献
104.
时虹 《现代塑料加工应用》2014,26(5):45-48
以不对称薄壳手机注塑件为研究对象,运用Moldflow软件对模具非平衡布置的浇注系统进行优化设计。通过变截面法改变各分流道的截面尺寸和浇口尺寸,得到优化后的流道系统,实现了流动平衡;并通过对填充时间、速度/压力(V/P)转换点压力等的流动分析,验证了流动平衡,为同类产品的模具设计提供了参考依据。 相似文献
105.
《International Journal of Circuit Theory and Applications》2017,45(10):1397-1417
This paper develops a simple design of unit cells to be taken in use in series‐connected multilevel inverters. The proposed structure not only reduces the part counts efficiently but also increases the number of generated levels in the output voltage. By aggregating the cascaded series‐connected units as the basic module, the proposed structure follows one H‐bridge circuit. The basic module acts as the initial stage in direct current/alternative current conversion within which all the positive and zero levels are produced. Afterwards, the H‐bridge circuit affords the production of symmetric sine‐wave by realizing negative levels. To assure the expected operational objectives, we developed three different algorithms to determine the magnitude of input direct current voltage sources. Moreover, to further investigate the proposed structure, different switching algorithms such the fundamental switching frequency and pulse width modulation level shifting approaches are implemented and compared with each other. Extensive numerical and experimental studies are conducted to yield in a suitable evaluation platform. The obtained results demonstrate a superior performance of the proposed structure rather than the conventional topologies. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
106.
郭丰启 《感光科学与光化学》1998,(2):186-190
不对称五氮齿镉和铟大环配合物的合成及其光物理性质研究郭丰启孙文芳谢洁王夺元(中国科学院感光化学研究所,北京100101)关键词不对称五氮齿金属配合物,电子吸收光谱,荧光1997年9月3日收到初稿,1997年12月30日收到修改稿.国家自然科学... 相似文献
107.
Björn V. Adalbjörnsson Helen S. Toogood Dr. Anna Fryszkowska Dr. Christopher R. Pudney Dr. Thomas A. Jowitt Dr. David Leys Dr. Nigel S. Scrutton Prof. 《Chembiochem : a European journal of chemical biology》2010,11(2):197-207
We report the crystal structure of a thermophilic “ene” reductase (TOYE) isolated from Thermoanaerobacter pseudethanolicus E39. The crystal structure reveals a tetrameric enzyme and an active site that is relatively large compared to most other structurally determined and related Old Yellow Enzymes. The enzyme adopts higher order oligomeric states (octamers and dodecamers) in solution, as revealed by sedimentation velocity and multiangle laser light scattering. Bead modelling indicates that the solution structure is consistent with the basic tetrameric structure observed in crystallographic studies and electron microscopy. TOYE is stable at high temperatures (Tm>70 °C) and shows increased resistance to denaturation in water‐miscible organic solvents compared to the mesophilic Old Yellow Enzyme family member, pentaerythritol tetranitrate reductase. TOYE has typical ene‐reductase properties of the Old Yellow Enzyme family. There is currently major interest in using Old Yellow Enzyme family members in the preparative biocatalysis of a number of activated alkenes. The increased stability of TOYE in organic solvents is advantageous for biotransformations in which water‐miscible organic solvents and biphasic reaction conditions are required to both deliver novel substrates and minimize product racemisation. 相似文献
108.
Response of the vortical flow around a slender body of revolution at high incidence to the shift of a single nose perturbation was investigated systematically using numerical methods. A minute geometric bump was employed to act as the nose perturbation, and all computations were performed for subsonic flows at incidence of 50°. The computational results show that the vortical flow is more sensitive to the perturbation located axially closer to the nose apex of a slender body. With perturbation shifting axia... 相似文献
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