• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.06a
• /
• pp.561-562
• /
• 2008

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.1288-1293
• /
• 2007

The present study covers the design and analysis of a thermionic scanning electron microscope (SEM) column. The SEM column contains an electron optical system in which electrons are emitted and moved to form a focused beam, and this generates secondary electrons from the specimen surfaces, eventually making an image. The electron optical system mainly consists of a thermionic electron gun as the beam source, the lens system, the electron control unit, and the vacuum unit. In the design process, the dimension and capacity of the SEM components need to be optimally determined with the aid of finite element analyses. Considering the geometry of the filament, a three-dimensional (3D) finite element analysis is utilized. Through the analysis, the beam emission characteristics and relevant trajectories are predicted from which a systematic design of the electron optical system is enabled. The validity of the proposed 3D analysis is also discussed by comparing the directional beam spot radius. As a result, a prototype of a thermionic SEM is successfully developed with a relatively short time and low investment costs, which proves the adoptability of the proposed 3D analysis.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.5
• /
• pp.122-128
• /
• 2007

The electric part of thermal SEM(Scanning Electron Microscopy) consists of high voltage generation, lens control, and image processing. Several methodologies for enhancing SEM image are addressed and those results are verified through analyses and experiments. The controller employes a DSP(Digital Signal Processing), making the system more flexible and convenient than the classical analogue based controller. In some parts based the analog circuit, there are inevitable sources of noise and image distortion. The experimental investigation is provided along with analytical proof to enhance the SEM image.

• Laser Solutions
• /
• v.18 no.3
• /
• pp.6-8
• /
• 2015

Finishing process includes deburring, polishing and edge radiusing. It improves the surface profile of specimen and eliminates the alien substance on surface. Deburring is the elimination process for debris of edges. Polishing lubricates surfaces by rubbing or chemical treatment. There are two types for electron finishing. The one is using pulse beam. The other is using the convergent and scanning electron beam. Pulse type device appropriates the large area process. But it does not control the beam dosage. Scanning type device has advantages for dosage control and edge deburring. We design the convergence and scan type. It has magnetic lenses for convergence and scan device for scanning beam. Magnetic lenses consist of convergent and objective lens. The lenses are designed by the specification(beam size and working distance). In this paper, we evaluate the convergence performance by pattern process. Also, we analysis the results and important factors for process. The important factors for process are beam size, pressure, stage speed and vacuum. These results will be utilized into systematizing pattern shape and the factors.

• Applied Microscopy
• /
• v.36 no.3
• /
• pp.227-234
• /
• 2006

To investigate the comparative effect of spherical and aspherical RGP lens were worn during 3 weeks on rabbit's cornea. Four white rabbits were worn right eyes with spherical lens and 4 white rabbits were worn right eyes with aspherical RGP lens. Left eyes were served as control. The rabbits were sacrificed at 3 weeks after fitting and observed morphological changes by scanning electron microscopy and also investigate proliferation rate of the corneal epithelium with RGP wearing. After spherical RGP lens wearing, the epithet layer damaged compared to aspherical lens. The superficial cell layer strip off seriously, cell size significantly changed abnormal. Both spherical and aspherical RGP lens fitting group showed so many bacteria and back surface of lens was found like a fern shape. The aspherical RGP lens original material type was some formal than spherical lens. We thought that these pattern was significantly altered with spherical lens by prohibited transmitter oxygen from atmosphere therefore the epithelium shape was changed. This suggested wearing the aspherical lens might be less physiologic than shperical lens fitting.

• Journal of Korean Ophthalmic Optics Society
• /
• v.15 no.3
• /
• pp.227-234
• /
• 2010

Purpose: The cleaning effect of protein deposit and the change of contact lens parameters by ultrasonic cleaner for eye glasses on the soft contact lenses were investigated. Methods: Etafilcon A contact lenses contaminated with protein, was ultrasonicated by ultrasonic cleaner for eye glasses and for the control group, spoiled contact lenses were cleaned by multi-purpose solution. The remaining protein deposits on the contact lenses were determined after extraction and the changes of overall diameter, base curve, center thickness power, and water contents on contact lenses were measured and surfaces of contact lenses were observed by scanning electron microscope. Results: The cleaning efficacies of multi-purpose solution on protein deposited etafilcon A contact lenses were 6.08%, and 23.73~33.92% in the group of ultrasonic cleaner for eye glasses with multi-purpose solution and 0~12.99% in the group of ultrasonic clear for contact lens with multipurpose solution depending on the treatment time. The changes of parameters and surface on contact lenses by ultrasonication were not observed. Conclusions: Ultrasonic cleaner for eye glasses can be used to eliminate protein deposits for the diagnostic soft contact lens in the office since it was effective to eliminate protein deposits and not caused change of parameters on soft contact lenses.

• Laser Solutions
• /
• v.18 no.4
• /
• pp.17-22
• /
• 2015

In this paper, ablation rate of $Al_2O_3$ ceramics by femtosecond laser fluence is derived with experimental method. The automatic three axis linear stage makes laser optics to move with high spatial resolution. With 10 times objective lens, minimal pattern width of $Al_2O_3$ is measured in the focal plane. Ablated surface area is shown as linear tendency increasing number of machining times with various laser power conditions. Machining times is most sensitive condition to control $Al_2O_3$ pattern width. Also, the linear increment of pattern width with laser power change is investigated. In high machining speed, the ablation volume rate is more linear with fluence because pulse overlap is minimized in this condition. Thermal effect to surrounding medium can be minimized and clean laser process without melting zone is possible in high machining speed. Ablation volume rate decelerates as increasing machining times and multiple machining times should be considered to achieve proper ablation width and depth.

• Journal of the Korean institute of surface engineering
• /
• v.37 no.4
• /
• pp.220-225
• /
• 2004

A new ion beam extraction system is designed using a simple ion mass filter and a micro mass balance and a QMS based detecting system. A quadrupole Mass Filter is used for selective ion beam formation from inductively coupled high density plasma sources with appropriate electrostatic lens and final analyzing QMS. Also a quartz crystal microbalance is set between a QMF and a QMS to measure the etching and polymerization rate of the mass selected ion beam. An inductively coupled plasma was used as a ion/radical source which had an electron temperature of 4-8 eV and electron density of $4${\times}$10^{11}$＃/㎤. A computer interfaced system through 12bit AD-DA board can control the pass ion mass of the qmf by setting RF/DC voltage ratio applied to the quadrupoles so that time modulation of pass ion's mass is possible. So the direct measurements of ion - surface chemistry can be possible in a resolution of $1\AA$/sec based on the qcm's sensitivity. A full set of driving software and hardware setting is successfully carried out to get fundamental plasma information of the ICP source and analysed $Ar^{+}$ beam was detected at the $2^{nd}$ QMS.

• Journal of the East Asian Society of Dietary Life
• /
• v.27 no.2
• /
• pp.114-123
• /
• 2017

This study added black lentil ethanol extract to Yakgwa at ratios of 0%, 0.5%, 1.0%, and 2.0%, and its quality characteristics were compared to those of the synthetic antioxidant BHT added to Yakgwa. Yakgwa with black lentil extract had lower moisture content than Yakgwa with BHT (3.98%) but higher content than the control group (5.72%). Higher black lentil extract resulted in less moisture content (p<0.001) as well as a faster expansion rate and oil absorption rate (p<0.001). Scanning Electron Microscopy (SEM) showed that as black lentil extract content increased, pores merged and collapsed, whereas the number of pores decreased and pore size became larger. For chromaticity, all L, a, and b values of the group containing black lentil extract were higher compared to the control group and group with BHT (p<0.001). For texture, as amount of added black lentil extract increased, hardness (p<0.001) and gumminess (p<0.01) increased while cohesiveness (p<0.01) decreased compared to the control group. For sensory characteristics, Yakgwa with 1.0% black lentil extract showed the best preference for all items except for off-flavor. Thus, 1.0% black lentil added to Yakgwa was the best in terms of functionality including preference.

• Journal of Korean Ophthalmic Optics Society
• /
• v.12 no.3
• /
• pp.19-25
• /
• 2007

It was studied how using soft contact lens multi-purpose solution (MPS), often used for medical treatment, effects the inhibition on cell growth, and how using the MPS demages eye cells, on rabbit eye's corneal epithelium and endothelium tissue. $ReNu^{(R)}$ (Baush & Lomb, USA), Opti-free $express^{(R)}$ (Alcon, USA), Free-sol $plus^{(R)}$ (Hanamedicon, Korea) were used as MPS. After culturing Clone 1-5C-4 cell lines (Human conjunctival cell lines), cell growth inhibition rate was measured by MIT assay. By making Hematoxylin and Eosin stain specimen, the morphology was observed by optical microscope. In the In vivo experiment, 9 white rabbit eyes (18 eyes) were classified into 3 groups. The experiment group is left eyes (9 eyes) of rabbit, and MPS were dropped; however the control group, the right eyes (9 eyes), were only used a saline solution without a preservatives. After the dropping within the period, the cornea surface of rabbit endothelium tissue was observed using scanning electron microscopy (SEM).