Selective Heating of Transition Metal Usings Hydrogen Plasma and Its Application to Formation of Nickel Silicide Electrodes for Silicon Ultralarge-Scale Integration Devices

We developed an apparatus for producing high-density hydrogen plasma. The atomic hydrogen density was 3.1 × 1021 m?3 at a pressure of 30 Pa, a microwave power of 1000 W, and a hydrogen gas flow rate of 10 sccm. We confirmed that the temperatures of transition-metal films increased to above 800。C within 5 s when they were exposed to hydrogen plasma formed using the apparatus. We applied this phenomenon to the selective heat treatment of nickel films deposited on silicon wafers and formed nickel silicide electrodes. We found that this heat phenomenon automatically stopped after the nickel slicidation reaction finished. To utilize this method, we can perform the nickel silicidation process without heating the other areas such as channel regions and improve the reliability of silicon ultralarge-scale integration devices.

Incorporating metal nanoparticles in porous materials via selective heating effect using microwave

Metal nanoparticle@porous material composites have attracted increasing attention due to their excellent synergistic catalytic performance.However,it is a challenge to introduce metal nanoparticles into cavities of porous materials without agglomeration on the exterior.Despite the progress achieved,a universal approach that can integrate different kinds of metal nanoparticles and porous materials is still highly desirable.Here we report a facile and general approach to fabricating metal nanoparticle@porous materials by microwave-triggered selective heating.The microwave can pass through the non-polar solvent and act on the polar solvent in the porous materials,causing the polar solvent to be heated,vaporized,and away from the pores of porous materials.The local void produced by the escape of polar solvent facilitates non-polar solvent containing metallic precursor to be dragged into the narrow pores,followed by further reduction,resulting in the complete encapsulation of nanoparticles.A series of metal nanoparticles@porous materials,ranging from metal-organic frameworks(MOFs)to zeolites,are successfully prepared by this method and show excellent size selectivity in catalytic reactions.

Roles of rare earth oxide additives in millimeter-wave sintering of AlN

Roles of rare earth oxide （RE2O3） additives in millimeter-wave（MM） sintering of AIN were investigated from the standpoints of phase diagram, heating characteristics of rare earth oxides, and morphology of intergranular oxide phase. In the millimeter-wave sintering of AIN, densification temperature decreased with the decrease of the ionic radius of rare earth ion and was closely related with the eutectic temperature in the RE2Oa-Al2O3 binary system. The lowest densification temperature in the millimeter-wave sintering of AIN with Yb2O3 additive was attributed to the largest heating rate of Yb2O3-Al2O3 binary oxide under millimeter-wave radiation. Furthermore, the lowest densification temperature could be attained while selecting the Yb2O3 content so as to form the intergranular phase with the eutectic composition in the Yb2O3-Al2O3 binary system. The result showed good agreement with the above mentioned during the sintering of Si3N4 with Yb2O3-Al2O3 additive. From TEM observation, it was verified that film-like intergranular oxide phase formed under millimeter-wave radiation was favorable for attaining high thermal conductivity in the Yb2O3 added AINs.

The Capacitive Coupling Modalities for Oncological Hyperthermia

The local-regional oncological hyperthermia has various electromagnetic methods for energy-transfer. The differences involve conceptual considerations and technical solutions. The most frequently applied energy transfer is capacitive coupling, concentrating the electric field to be the active heating component. The realization of the capacitive coupling set-up is divided into two different categories based on their goals for heating: 1) the homogeneous (conventional) heating, using isothermal conditions for dosing, and 2) the selective heterogeneous heating, using cellularly absorbed energy for dosing. The homogeneous heating utilizes plane-wave matching, absorbing the wave for energy transfer. The heterogenic heating uses impedance matching, selecting the malignant cells by their electromagnetic specialties, like their heterogenic impedance, higher membrane-raft density, and different spatio-temporal (pathologic pattern) arrangements. This article’s objective is to compare and discuss the details of the two kinds of capacitive coupling techniques.

Additive manufacturing of composite materials and functionally graded structures using selective heat melting technique

The feasibility of using selective heat melting(SHM) to fabricate composite materials and functionally graded structures was investigated.We report,for the first time,the successful 3 D printing of copper(Cu)-polyethylene(PE) composite,iron(Fe)-polyethylene(PE) composite and functionally graded CuO foams using the SHM technique.It was found that a low feed rate,high airflow rate and high airflow temperature were required for efficient delivery of heat from the emitted hot air to the powder bed,so that the PE binder particles can melt and form dense composites with smooth surfaces.The best mechanical properties were exhibited by composites with 80 vol.% PE,as lower PE concentrations led to deficient binding of the metal particles,while higher PE concentrations meant that very few metal particles were available to strengthen the composite.The strength exhibited by Cu-PE composites was comparable to engineering plastics such as polycarbonate,with the added advantage of being electrically conductive.The average conductivity of the samples,0.152±0.28 S/m,was on par with physically crosslinked graphene assemblies.By subjecting a Cu-PE composite,with Cu concentration graded from 10 vol.% to 30 vol.%,to a high temperature debinding and sintering treatment in air,CuO foam with graded porosity can be obtained.This CuO foam was observed to fail in a layer-by-layer manner under mechanical compression,which is a characteristic of functionally graded materials.Our study shows that,compared to existing 3 D printing techniques,SHM can be cheaper,have wider material compatibility,occupy a smaller footprint and potentially induce less residual stresses in the fabricated parts.Therefore,it could be a valuable complement to current additive manufacturing techniques for fabricating mechanically strong composite materials and functionally graded structures.