Plasma-Assisted ALD of Highly Conductive HfNx: On the Effect of Energetic Ions on Film Microstructure

Plasma Chemistry and Plasma Processing - In this work, we report on the atomic layer deposition (ALD) of HfNx thin films by employing CpHf(NMe2)3 as the Hf(IV) precursor and Ar–H2 plasma in...     

Thin Film Flow of a Second Grade Fluid over a Stretching/Shrinking Sheet with Variable Temperature-Dependent Viscosity

Effects of variable viscosity on the flow and heat transfer in a thin film on a horizontal porous stretching sheet are analyzed. The steady boundary layer equations for momentum and thermal energy are simplified by using similarity transformations. The resulted and coupled nonlinear differential equations are solved by Homotopy analysis method. The results are presented graphically to interpret various physical parameters appearing in the problem.     

P-Al/NaX结构和酸碱性位调控对甲苯甲醇侧链烷基化性能影响

采用水热法原位合成了P-Al/NaX催化剂,然后通过浸渍NaOH对其进行酸碱性调控,并探究了它在甲苯甲醇侧链烷基化反应中的催化性能。结合X射线衍射（XRD）、X射线光电子能谱（XPS）、N₂吸附-脱附等表征及催化活性数据发现,原位负载P、Al后,合成的磷铝硅酸盐（Na₁₃Al₂₄Si₁₃P₁₁O₉₆·H₂O）结构展现出较好的甲苯甲醇侧链烷基催化活性;随着NaOH负载量的增加,乙苯和苯乙烯的选择性呈先上升后下降的趋势,当负载质量分数为9%的NaOH时,苯乙烯选择性为45.84%,乙苯和苯乙烯的收率之和达到63.08%。这可能是由于NaOH的负载有利于催化剂表面碱性的提高和酸性的降低,而高的强碱性位和弱酸性位数量有利于甲苯甲醇侧链烷基化反应的进行。     

保护家电和专业电子系统组件的利器—协同电路保护方案

在各种家电和各种专业设备中的电机、控制器和诸多的电子部件,均可得益于所用的协同电路保护。如今的高分子正温度系数（PPTC）过电流保护部件,能够提供极低的电阻．并且在体积上也能与传统的保险丝解决方案相匹敌。就像传统的保险丝一样,可以限制故障条件下所产生的危险大电流。然而除此之外,这种PPTC部件还能够在故障消除以及为电路供电的电源重新供电后,直接实现自复能力,从而无需更换熔断的保险丝。     

Experimental study on broadband radiofrequency electromagnetic radiations near cellular base stations: a novel perspective of public health

Journal of Thermal Analysis and Calorimetry - The purpose of this study is to measure and document the maximum level of broadband radiofrequency electromagnetic radiations in the vicinity of...     

An adaptive resource management for mobile terminals on vertical handoff

Mobile communications and wireless networks are developing at a fast pace. The increasing number of mobile subscribers and terminals are the real life evidence of the fast growing development in the area of wireless communication. Wireless communication technology is now pursuing 4G (fourth generation) and seeking a scheme to provide quality of service (QoS) to the various applications continuously even moving to another network. In this paper, we proposed a dynamic resource management architecture which considers vertical handoff situation with minimal disruption of service to the users considering seamless provision of QoS. The proposed scheme efficiently manages resources and provides stable services to the mobile terminal. The simulation results show that resource management enabled mobile terminals utilize system resources, CPU and memory, efficiently improved by 40% and 65%, respectively, rather than mobile terminals without resource tuning.     

Structural and physical properties of Mg3−xZnxSb2 (x=0-1.34)

The Mg_3−xZn_xSb₂ phases with x=0-1.34 were prepared by direct reactions of the elements in tantalum tubes. According to the X-ray single crystal and powder diffraction, the Mg_3−xZn_xSb₂ phases crystallize in the same P3¯m1 space group as the parent Mg₃Sb₂ phase. The Mg_3−xZn_xSb₂ structure is different from the other substituted structures of Mg₃Sb₂, such as (Ca, Sr, Ba) Mg₂Sb₂ or Mg_5.23Sm_0.77Sb₄, in a way that in Mg_3−xZn_xSb₂ the Mg atoms on the tetrahedral sites are replaced, while in the other structures Mg on the octahedral sites is replaced. Thermoelectric performance for the two members of the series, Mg₃Sb₂ and Mg_2.36Zn_0.64Sb₂, was evaluated from low to room temperatures through resistivity, Seebeck coefficient and thermal conductivity measurements. In contrast to Mg₃Sb₂ which is a semiconductor, Mg_2.36Zn_0.64Sb₂ is metallic and exhibits an 18-times larger dimensionless figure-of-merit, ZT, at room temperature. However, thermoelectric performance of Mg_2.36Zn_0.64Sb₂ is still poor and it is mostly due to its large electrical resistivity.     

Influence of tungsten doping concentration on the electronic and optical properties of anatase TiO2

The structural, electronic and optical properties of tungsten-doped TiO₂ have been investigated using density functional theory with plane wave basis sets and ultrasoft pseuodopotential. Substitutional W doping at Ti sites create W 5d states just below the conduction band minimum while interstitial W doping gives isolated W 5d states in the middle of forbidden region. Averaged bond lengths show that W doping at Ti sites produce minimum structural distortion as compared to the interstitial W-doped TiO₂. Substitutional W-doped TiO₂ has better visible light absorption compared to interstitial W-doped TiO₂ and has stable configuration which provide reasonable explanation for the experimental findings. Tungsten doping in TiO₂ with different doping concentrations is investigated as an enabling concept for enhancing the visible light absorption. Optical properties show that optimal W doping concentration would improve the visible light absorption. 2.08% W doping concentration gives strong visible and ultraviolet light absorption among all doped models found consistent with experiments.     

因应新兴市场趋势的电路保护方案

电子部件生产商一直面临紧跟着业界发展步伐的挑战,尤其是在汽车、工业、消费电子和电信应用方面,电子部件数量的成长和高密度,更让人眼花缭乱。     

功率电子系统的电路保护考虑

随着家庭、办公室和车辆中高功率电子设备应用的持续成长,推动着走向新材料和更高效率电源部件的发展趋势。电子设备中电源密度的急剧成长,使得不断缩小的体积已经导致了更多的过热问题。简单来说,这些更热、更高密度的电源PCB板需要更强大、更可靠的热管理。