Understanding silica-supported metal catalysts: Pd/silica as a case study

Supported metal catalysts, particularly noble metals supported on SiO₂, have attracted considerable attention due to the importance of the silica–metal interface in heterogeneous catalysis and in electronic device fabrication. Several important issues, e.g., the stability of the metal–oxide interface at working temperatures and pressures, are not well-understood. In this review, the present status of our understanding of the metal–silica interface is reviewed. Recent results of model studies in our laboratories on Pd/SiO₂/Mo(1 1 2) using LEED, AES and STM are reported. In this work, epitaxial, ultrathin, well-ordered SiO₂ films were grown on a Mo(1 1 2) substrate to circumvent complications that frequently arise from the silica–silicon interface present in silica thin films grown on silicon.     

Self-aligned offset gated poly-Si TFTs with a floating sub-gate

We have fabricated a self-aligned offset-gated poly-Si thin film transistor (TFT) by employing a novel photoresist reflow process. The gate structure of the new device is consisted of two unique patterns: A main-gate and a sub-gate. The new fabrication method extends the gate-oxide over the offset region. With the assistance of the sub-gate and reflowed photoresist a self-aligned offset region is successfully obtained due to the offset oxide acting as an implantation mask. The poly-Si TFT with symmetrical offsets is easily fabricated and the new method does not require any additional offset mask step. Compared with the misaligned offset gated poly-Si TFTs, excellent symmetric electrical characteristics are obtained     

Total transfer capability computation for multi-area power systems

This paper presents a method for multi-area power system total transfer capability (TTC) computation. This computation takes into account the limits on the line flows, bus voltage magnitude, generator reactive power, voltage stability, as well as the loss of line contingencies. The multi-area TTC problem is solved by using a network decomposition approach based on REI-type network equivalents. Each area uses REI equivalents of external areas to compute its TTC via the continuation power flow (CPF). The choice and updating procedure for the continuation parameter employed by the CPF is implemented in a distributed but coordinated manner. The proposed method leads to potential gains in the computational efficiency with limited data exchanges between areas. The developed procedure is successfully applied to the three-area IEEE 118-bus test system. Numerical comparisons between the integrated and the proposed multi-area solutions are presented for validation.     

A new alloy design concept for austenitic stainless steel with tungsten modification for bipolar plate application in PEMFC

The feasibility of a new alloy design concept utilizing the principle of ‘tungsten bronze effect’ is critically evaluated for the development of metallic bipolar plates for proton exchange membrane fuel cell (PEMFC). An austenitic stainless steel (ASS) is modified with W and La to improve the stability of the passive film in an acidic environment as well as to reduce the contact resistance by the tungsten bronze effect. The experimental ASS containing W and La was evaluated in a simulated PEMFC environment of H₃PO₄ and H₂SO₄ solutions at 80 °C, and the electrical property was evaluated by performing a contact resistance test. The test results show that the ASS modified with W and La has good passive film stability for corrosion resistance and low contact resistance. The X-ray photoelectron spectroscopy (XPS) analysis clearly suggests the possibility of the tungsten bronze effect from the change in valency state of W⁶⁺ to W⁵⁺ in the passive film formed on the modified ASS. The feasibility of a new alloy design concept utilizing the ‘tungsten bronze effect’ is well demonstrated; however, more study is highly required for the development of metallic bipolar plates of PEMFC.     

网络媒介影响下建筑相关问题初探

自工业革命以来形成的社会生活方式,在信息数字技术的影响下发生着悄无声息的变化.从原子到比特,数字化生存是必然的趋势.网络媒介的出现使得人们在交流和机会等方面获得平等的权利.随之产生的人们的生活方式、行为的改变已经为艺术领域带来了新的变化.通过对艺术创作的考察,为建筑领域的相关问题提供了参照、借鉴.在建筑创作中,＂图＂与＂底＂的关系正在模糊化,信息交流方式更多样化并具有一定的阶段性,动态的模数将导致更具个性化的设计,空间界面更为柔化,设计成果的生成也具有了更多的不可预见性.     

图像阈值自动选取算法的C＋＋实现

图像分割是运动目标检测与跟踪技术必须要解决的问题,在很多时候它涉及到图像阈值的选取。文章采用的算法首先计算图像中不同区域的灰度均值,结合最小差值条件,反复修订由计算所得的阈值,从而达到自动选优的目的。在此基础上,文章进一步给出了用C＋＋语言实现算法的关键代码。测试表明此方法选择阈值简便实用,图像的二值化效果良好。