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21.
Infrared vibrational spectroscopy in an attenuated total reflection (ATR) geometry has been employed to investigate the presence of organic thin layers on Si-wafer surfaces. The phenomena have been simulated to show there can be a field enhancement with the presented single-reflection ATR (SR-ATR) approach which is substantially larger than for conventional ATR or specular reflection. In SR-ATR, a discontinuity of the field normal to the film contributes a field enhancement in the lower index thin film causing a two order of magnitude increase in sensitivity. SR-ATR was employed to characterize a single monolayer of undecylenic acid self-assembled on Si(1 1 1) and to investigate a two monolayer system obtained by adding a monolayer of bovine serum albumin protein. 相似文献
22.
On the use of fuzzy inference techniques in assessment models: part I—theoretical properties 总被引:2,自引:0,他引:2
An assessment model is a mathematical model that produces a measuring index, either in the form of a numerical score or a
category to a situation/object, with respect to the subject of measure. From the numerical score, decision can be made and
action can be taken. To allow valid and useful comparisons among various situations/objects according to their associated
numerical scores to be made, the monotone output property and the output resolution property are essential in fuzzy inference-based
assessment problems. We investigate the conditions for a fuzzy assessment model to fulfill the monotone output property using
a derivative approach. A guideline on how the input membership functions should be tuned is also provided. Besides, the output
resolution property is defined as the derivative of the output of the assessment model with respect to its input. This derivative
should be greater than the minimum resolution required. From the derivative, we suggest improvements to the output resolution
property by refining the fuzzy production rules. 相似文献
23.
24.
An integral equation formulation for buoyancy-driven convection problems is developed and illustrated. Buoyancy-driven convection in a bounded cylindrical geometry with a free surface is studied for a range of aspect ratios and Nusselt numbers. The critical Rayleigh number, the nature of the cellular motion, and the heat transfer enhancement are computed using linear theory. Green's functions are used to convert the linear problem into linear Fredholm integral equations. Theorems are proved which establish the properties of the eigenvalues and eigenfunctions of the linear integral operator which appears in these equations. 相似文献
25.
Yew Hoong Leong Jaguthsing Dindyal Tin Lam Toh Khiok Seng Quek Eng Guan Tay Sieu Tee Lou 《ZDM》2011,43(6-7):819-831
Problem solving is at the heart of the Singapore Mathematics curriculum. However, it remains a challenge for teachers to realise this curricular goal in practice. Here, we review the efforts of Singapore mathematics teacher educators in incorporating problem-solving (teaching) competency in teacher education and PD programmes. We discuss conceptual and practical issues, actions taken and changes made in building teachers?? capacity to enact a problem-solving curriculum in a school-based design experiment project. In the project, teachers learnt problem solving, observed and then carried out lessons, using the ??Mathematics Practical????akin to the science practical??as key to instruction and assessment. 相似文献
26.
Green emission can be identified as either a structured or a structureless emission. In the downward surface band bending region, the influence of defects on the continuous change in the 0-0 electronic transition was found to be a dominating factor that differentiates the characteristics of green emission. Such a change in the 0-0 electronic transition gives rise to the structureless green emission at higher energy, while the 0-0 electronic transition in the bulk of ZnO plays an important role resulting in structured green emission with lower energy. 相似文献
27.
Yew Hoong Leong Eng Guan Tay Tin Lam Toh Khiok Seng Quek Jaguthsing Dindyal 《The Journal of Mathematical Behavior》2011,30(3):181-193
This study is based on the stance that Pólya's “Look Back,” though understudied, remains relevant to Mathematics curricula that place emphasis on problem solving. Although the Singapore Mathematics curriculum adopts the goal of teaching Look Back, research about how it is carried out in actual classroom practice is rare. In our project, we focus on a redesign of a teacher development programme that is targeted to help teachers realize Pólya's original vision of Look Back in the classroom. We report the cases of two teachers who have participated in the teacher development programme: their thinking about Look Back (through interview records) and their interpretation of Look Back in their classroom practice (through video records). By bringing these two spheres of data together, we discuss their degree of ‘buy-in’ to Look Back in the overall problem solving enterprise. 相似文献
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29.
Myint MT Kitsomboonloha R Baruah S Dutta J 《Journal of colloid and interface science》2011,354(2):810-815
The synthesis and properties of superhydrophobic surfaces based on binary surface topography made of zinc oxide (ZnO) microrod-decorated micropatterns are reported. ZnO is intrinsically hydrophilic but can be utilized to create hydrophobic surfaces by creating artificial roughness via microstructuring. Micron scale patterns consisting of nanocrystalline ZnO seed particles were applied to glass substrates with a modified ink-jet printer. Microrods were then grown on the patterns by a hydrothermal process without any further chemical modification. Water contact angle (WCA)(1) up to 153° was achieved. Different micro array patterned surfaces with varying response of static contact angle or sessile droplet analysis are reported. 相似文献
30.
Liu Zhaolin Tay Siok Wei Hong Liang Lee Jim Yang 《Journal of Solid State Electrochemistry》2011,15(1):205-209
Olivine-type LiFePO4 composite materials for cathode material of the lithium-ion batteries were synthesized by using a sol-gel method and were
coated by a chemical deposition of silver particles. As-obtained LiFePO4/C-Ag (2.1 wt.%) composites were characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD),
conductivity measurements, cyclic voltammetry, as well as galvanostatic measurements. The results revealed that the discharge
capacity of the LiFePO4/C-Ag electrode is 136.6 mAh/g, which is 7.6% higher than that of uncoated LiFePO4/C electrode (126.9 mAh/g). The LiFePO4/C coated by silver nanoparticles enhances the electrode conductivity and specific capacity at high discharge rates. The improved
capacity at high discharge rates may be attributed to increased electrode conductivity and the synergistic effect on electron
and Li+ transport after silver incorporation. 相似文献