Ultrasonography of benign vulvar lesions

Vincent Y. T. Cheung 대한초음파의학회 2018 ULTRASONOGRAPHY Vol.37 No.4

With the increasing applications of ultrasonography in the field of dermatology, this imagingmodality can be extended to identify and characterize common vulvar lesions, with a particularfocus on their location, size, vascularity, and content. This pictorial essay provides an introductionto vulvar ultrasonography, including technical considerations, ultrasonographic anatomy, and theultrasonographic appearances of some vulvar conditions.

Current status of high-intensity focused ultrasound for the management of uterine adenomyosis

Vincent Y. T. Cheung 대한초음파의학회 2017 ULTRASONOGRAPHY Vol.36 No.2

While high-intensity focused ultrasound has been used for some time in the management of uterine fibroids, its effectiveness and safety in managing adenomyosis is less well established. A literature review was performed of all eligible reports using this modality as a treatment for adenomyosis. Relevant publications were obtained from the PubMed electronic database from inception through March 2016. Eleven articles, including information from 1,150 treatments and follow-up data from 990 patients, were reviewed. High-intensity focused ultrasound appears to be effective and safe in the management of symptomatic adenomyosis, and can be considered as an alternative uterine-sparing option for women with this condition.

EffECTIVE PARTICULATES REDUCTION IN DIESEL ENGINES THROUGH THE USE OF FUEL CATALYSED PARTICULATE FILTERS

Vincent, M.-W.,Richards, P.-J.,Rogers, T.-J. The Korean Society of Automotive Engineers 2002 International journal of automotive technology Vol.3 No.1

There is Increasing world-wide interest in diesel particulate filters (DPF) because of their proven effectiveness in reducing exhaust smoke and particulate emissions. Fine particulates have been linked to human health . DPF use requires a means to secure the bum-out of the accumulated soot, a process called regeneration. If this is not achieved, the engine cannot continue to operate. A number of techniques are available, but most are complex, expensive or have a high electrical demand. The use of fuel additives to catalyse soot bum-out potentially solves the problem of securing regeneration reliably and at low cost. Work on organo-metallic fuel additives has shown that certain metals combine to glove exceptional regeneration performance. Best performance was achieved with a combination of iron and strontium based compounds. Tests were carried out un a bed engine and on road vehicles, which demonstrated effective and reliable regeneration from a tow dose fuel additive, using a single passive DPF. No control valves, flow diverters. heaters or other devices were employed to assist regeneration. Independent particle size measurements showed that there were no harmful side effects from the use of the iron-strontium fuel additive.

Effect of the Pressure Ratio on the Starting-Up Process of a Vacuum Ejector-Diffuser System

Vincent Lijo,김희동(Heuy-Dong Kim),T. Setoguchi 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5

The objective of the present study is to analyze the effect of pressure ratio on the start-up process of an ejector with finite volume secondary chamber. The present study is also intended to identify the evacuation performance of vacuum ejector-diffuser systems under different pressure ratios and to identify an optimum pressure ratio which will give the lowest possible vacuum inside the secondary chamber with minimum time required to reach steady state operation. Commercial software Fluent 6 is used to perform the analysis. The results obtained show that the there exists an optimal pressure ratio for the maximum evacuation performance and ejector performance is increased for this pressure ratio by the prevention of back-flow into the secondary chamber. The one and only condition in which a back-flow into the secondary chamber is eliminated in such types of ejectors is the diffuser starting mode. It is also shown that in the diffuser un-starting mode there is always circulation into the secondary chamber which was detrimental to the ejector performance particularly when it is used in HAT facilities as it can lead to resonating vibration when the natural frequency of the test nozzle coincides with the pressure fluctuation inside the secondary chamber caused by recirculation.

Influence of AVS on the Partitioning of Bioavailable Zn to Various Binding Phases in Sediments

송기훈,Vincent T. Breslin 한국해양과학기술원 2004 Ocean science journal Vol.39 No.4

Sediment microcosm experiments were conducted for 14 and 28 days using Zn spiked sediment to examine the changing distribution of bioavailable sediment-bound Zn at different SEM (simultaneously extracted metal)-Zn/ AVS (acid volatile sulfide) mole ratios as a function of time and amphipod density. In surficial sediments (0-1 cm), AVS concentrations significantly decreased due to bioturbation and oxidation, while SEM-Zn concentrations remained unchanged. As a result, SEM-Zn/AVS ratios in the surface sediment were greater one although the ratios were designed as less than one initially. With increasing SEM-Zn/AVS ratios in surficial sediments, concentrations of potentially bioavailable MgCl2 extractable-Zn, NaOAc extractable-Zn and pore water-Zn significantly increased, while concentrations of SEM-Zn were not significantly varied. Results suggested that as AVS concentrations decreased, AVS bound Zn was partitioned to other sediment fractions (i.e. MgCl2 and NaOAc extractable) and the pore water, resulting in changes in Zn bioavailability in surficial sediments. Concentrations of AVS, SEM-Zn and pore water-Zn remained unchanged in the deeper layers (>1 cm) of the sediment.

진공 이젝터-디퓨져 시스템내의 비정상 유동 과정에 관한 연구

Lijo Vincent,김희동(Heuydong Kim),T.Setoguchi 한국추진공학회 2009 한국추진공학회 학술대회논문집 Vol.2009 No.5

The objective of the present study is to analyze the transient flow through theejector system with the help of a computational fluid dynamics (CFD) method. An attempt is made to investigate the interesting and conflicting phenomenon of the infinite entrainment into the primary stream without an infinite mass supply from the secondary chamber. The results obtained show that the one and only condition in which an infinite mass entrainment can be possible in such types of ejectors is the generation of a re-circulation zone near the primary nozzle exit. The flow in the secondary chamber attains a state of dynamic equilibrium of pressures at the onset of the recirculation zone. A steady flow in the ejector system is valid only after this point.

Diffusion of Mn in ZnO nanowires annealed in air.

Phan, T L,Sun, Y K,Vincent, R,Cherns, D,Yu, S C American Scientific Publishers 2009 Journal of Nanoscience and Nanotechnology Vol.9 No.2

<P>We studied diffusion of Mn in ZnO nanowires by means of field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, photoluminescence and Raman scattering spectroscopy. The Mn-diffused samples were prepared by covering synthesized ZnO nanowires with a Mn chip and then annealing at temperatures between 200 and 1000 degrees C for 1 h in air. Microstructural analyses, and photoluminescence and Raman studies revealed that Mn atoms started diffusing in ZnO nanowires at 800 degrees C. The annealing-temperature increase up to 1000 degrees C led to a strong diffusion of Mn in the ZnO host lattice, which caused the blueshift of the ultra-violet emission. Concurrently, recored Raman scattering spectra showed some additional Mn-related modes. The origin of these lines was discussed in detail.</P>

EFFECTIVE PARTICULATES REDUCTION IN DIESEL ENGINES THROUGH THE USE OF FUEL CATALYSED PARTICULATE FILTERS

M. W. Vincent",P. J. Richards,T. J. Rogers 한국자동차공학회 2002 International journal of automotive technology Vol.3 No.1

There is increasing world-wide interest in diesel particulate filters (DPF) because of their proven effectiveness in reducing exhaust smoke and particulate emissions. Fine particulates have been linked to human health. DPF use requires a means to secure the burn-out of the accumulated soot, a process called regeneration. If this is not achieved, the engine cannot continue to operate. A number of techniques are available, but most are complex. expensive<br/> or have a high electrical demand. The use of fuel additives to catalyse soot bum-out potentially solves the problem of securing regeneration reliably and at low cost. Work on organo-metallic fuel additives has shown that certain metals combine to give exceptional regeneration performance. Best performance was achieved with a combination of iron and strontium based compounds. Tests were carried out on a bed engine and on road vehicles, which demonstrated effective and reliable regeneration from a low dose fuel additive. using a single passive DPF. No control valves, flow diverters, heaters or other devices were employed to assist regeneration. Independent particle size measurements showed that there were no harmful side effects from the use of the iron-strontium fuel additive.<br/>

Fabrication and Characterization of Hybrid Natural Fibre-Reinforced Sandwich Composite Radar Wave Absorbing Structure for Stealth Radomes

V. Antony Vincent,C. Kailasanathan,G. Ramesh,T. Maridurai,V. R. Arun Prakash 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.6

Natural fibre based sandwich composite wave absorbing structures were prepared and characterized for stealth and radome applications. The principal aim of this research was to develop a novel sandwich radar wave absorbing composite structure and evaluating their wave transmission and flexural properties. Fibres such as wool, silk, E-glass, aramid and wave absorbing foams like balsa wood, PVC and PMI were used for making wave absorbing sandwich composites. The composites were prepared using autoclave vacuum bag degassing method followed by post curing at 120 °C. The radar wave transmission characteristics were investigated using stealth radomes by partially replacing the traditional E-glass and aramid fi bre structure with a frequency selective surface (FSS) with standard parameters. The free space measurement technique was used to examine the radar wave transmission characteristics in the X-band frequency range (8.2–12.4 GHz). Three point bending test also performed to identify the fl exural strength of sandwich composite setup to ensure the bending rigidity. A highest wave transmission of 87.7% at bandwidth 0.83 GHz in − 1 dB with flexural strength of 44.2 MPa was observed for sandwich composite type 3c, which contains aramid/epoxy composite + balsa wood + silk/epoxy structure. The SEM micrographs showed highly reacted and toughness improved matrix phase for type 3c composite sandwich.

Effect of Counter-doping Thickness on Double-gate MOSFET Characteristics

George James T,Saji Joseph,Vincent Mathew 대한전자공학회 2010 Journal of semiconductor technology and science Vol.10 No.2

This paper presents a study of the influence of variation of counter doping thickness on short channel effect in symmetric double-gate (DG) nano MOSFETs. Short channel effects are estimated from the computed values of current-voltage (I-V) characteristics. Two dimensional Quantum transport equations and Poisson equations are used to compute DG MOSFET characteristics. We found that the transconductance (gm) and the drain conductance (gd) increase with an increase in p-type counter-doping thickness (Tc). Very high value of transconductance (gm= 38 mS/㎛) is observed at 2.2 ㎚ channel thickness. We have established that the threshold voltage of DG MOSFETs can be tuned by selecting the thickness of counter-doping in such device.