$C_{x}F_{y}$ Polymer Film Deposition in rf and dc $C_{7}F_{16}$ Vapor Plasmas

Sakai, Y.,Akazawa, M.,Sakai, Yosuke,Sugawara, H.,Tabata, M.,Lungu, C.P.,Lungu, A.M. The Korean Institute of Electrical and Electronic 2001 Transactions on Electrical and Electronic Material Vol.2 No.1

$C_{x}F_{y}$ polymer film was deposited in rf and dc Fluorinert vapor ($C_{7}F_{16}$) plasmas. In the plasma phase, the spatial distribution of optical emission spectra and the temporal concentration of decomposed species were monitored, and kinetics of the $C_{7}F_{16}$ decomposition process was discussed. Deposition of $C_{x}F_{y}$ film has been tried on substrates of stainless steel, glass, molybdenum and silicon wafers at room temperature in the vapor pressures of 40 and 100 Pa. The films deposited in the rf plasma showed excellent electrical properties as an insulator for multi-layered interconnection of deep-submicron LSI, i.e. the low dielectric constant ∼2.0, the dielectric strength ∼2 MV/cm and the high deposition rate ∼100nm/min at 100W input power.

Computational fluid dynamics simulations of interphase heat transfer in a bubbling fluidized bed

Jingdai Wang,Musango Lungu,Jingyuan Sun,Zichuan Zhu,Yongrong Yang 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.7

Numerical simulations based on the Eulerian-Eulerian approach have been performed in the study of interphaseheat transfer in a gas solid fluidized bed. The kinetic theory of granular flow (KTGF) has been used to describethe solid phase rheology. An assessment of drag models in the prediction of heat transfer coefficients shows that nomajor difference is observed in the choice of the drag model used. Fluctuations of the interphase heat transfer coefficienthave been found to be closely related to the bubble motion in the bed. Effects of the wall boundary condition, inletgas velocity, initial bed height and particle size on the predicted heat transfer coefficient have also been investigated. Typical temperature profiles in the bed show that thermal saturation is attained instantaneously close to the gas distributor. Simulated results of the coefficients are in fair agreement with those reported in literature.

Electronics Cooling Using the Porous Metallic Materials

Lucaci Mariana,Orban Radu L.,Lungu Magdalena,Enescu Elena,Gavriliu Stefania 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

The paper presents some results regarding the obtaining of some copper heat pipes with a porous copper internal layer for electronic components cooling. The heat pipes were realized by sintering of spherical copper powders of size directly on the internal side of a copper pipe of 18 mm in diameter. The obtained pipes were then brazed in order to obtain a heat pipe of 0.5 m in length. After that, the heat pipe was sealed and filled with a small quantity of distilled water as working fluid. To establish the total heat transport coefficient and the thermal flow transferred at the evaporator, some external devices were realized to allow the heating of the evaporator and the cooling of the condenser. Water heat pipes are explored in the intermediate temperature range of 303 up to 500 K. Test data are reported for copper water heat pipe, which was tested under different orientations. The obtained results show that the water heat pipe has a good thermal transfer performance in the temperatures range between 345 and 463 K.

Sintering of Alloyed Starting from Mechano-composites Powders

Lucaci Mariana,Orban Radu L.,Lungu Magdalena,Enescu Elena,Gavriliu Stefania 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Considering the idea that some properties, especially the mechanical properties of at ambient temperature can be improved by adding of some substitutional/interstitial elements, our goal was to obtain these materials starting from mechano-composites powders. In this aim, using mechanical alloying techniques three type of mechano-composite powders starting from elemental powders were obtained. Then, by reactive sintering in argon atmosphere at temperature over , alloyed materials were realized. This paper presents our research results regarding the microstructural aspects and phase formation in obtained materials.

High repetition rate laser ablation for vaporeliquidesolid nanowire growth

A. Marcu,F. Stokker,R.R. Zamani,C.P. Lungu,C. Grigoriu 한국물리학회 2014 Current Applied Physics Vol.14 No.4

A high repetition rate (500 kHz) solid state laser was used for the ablation process in a Pulsed Laser Deposition (PLD)/VaporeLiquideSolid (VLS) growing. A ZnO target was ablated with laser powers between 0.6 Wand 1.2 W, and a variable number of pulses per train and trains frequencies. ZnO structures were grown on gold patterned and unpatterned substrates surfaces. Enhanced growth of the nanostructures could be noticed on the catalyst patterned surfaces. Better nanowire morphologies were also observed for bigger number of laser pulses per train. The enhancements are more evident for low laser powers. Based on plume expansion investigations, by using a high speed camera and a Particle-In-Cell (PIC) Monte-Carlo based simulations, the nanostructure morphology variations could be understood on the basis of the plume particles diffusion process and thin film versus VLS growing competition.

Applicability of Industrial Sisal Fiber Waste Derived Activated Carbon for the Adsorption of Volatile Organic Compounds (VOCs)

Melike Dizbay-Onat,Evan Floyd,Uday K. Vaidya,Claudiu T. Lungu 한국섬유공학회 2018 Fibers and polymers Vol.19 No.4

Agricultural waste produced by the industry is a huge threat for the global environment. Utilization of agricultural waste is necessary and there is an urgent need to develop new techniques to solve this important problem. The main objective of this research was to evaluate the applicability of the activated carbon (AC) derived from industrial sisal fiber waste as passive samplers in monitoring toluene by comparing them to industry standard wafer and granular activated carbon (GAC). Carbonization time and ball milling effect on sisal fiber derived AC sample adsorption properties were investigated. Toluene adsorption isotherms were used to predict toluene adsorption capacities. Surface characteristics including surface area and pore volume were used to determine the relationships between them and adsorption capacity. Even though prepared AC samples have mesoporous structure, commercial samples have microporous structure. Surface area from 1245 m2/g to 1297 m2/g and toluene adsorption capacity from 21.4 % to 26.6 % was improved by increasing carbonization time from 1 h to 3 h at 650 oC carbonization temperature and 94.4 ml/min flow rate. Conversely, ball milling technique had negative effect by decreasing the surface area (674 m2/g) and the adsorption capacity of toluene (12.27 %). It is concluded that industrial sisal fiber waste have great potential as a precursor of AC for application in passive monitoring against toluene, particularly the produced mesoporous AC with 3 h carbonization time performs higher adsorption capacity (26.6 %) than commercially available microporous passive sampler (24.1 %) and GAC (22.8 %).

The Relationship Between Saccades And Locomotion

Anshul Srivastava,Omar F. Ahmad,Christopher Pham Pacia,Mark Hallett,Codrin Lungu 대한파킨슨병및이상운동질환학회 2018 Journal Of Movement Disorders Vol.11 No.3

Human locomotion involves a complex interplay among multiple brain regions and depends on constant feedback from the visual system. We summarize here the current understanding of the relationship among fixations, saccades, and gait as observed in studies sampling eye movements during locomotion, through a review of the literature and a synthesis of the relevant knowledge on the topic. A significant overlap in locomotor and saccadic neural circuitry exists that may support this relationship. Several animal studies have identified potential integration nodes between these overlapping circuitries. Behavioral studies that explored the relationship of saccadic and gait-related impairments in normal conditions and in various disease states are also discussed. Eye movements and locomotion share many underlying neural circuits, and further studies can leverage this interplay for diagnostic and therapeutic purposes.