• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.220-220
• /
• 1999

In plasma source ion implantation, the target is immersed in the plasma and repetitively biased by negative high voltage pulses to implant the extracted ions from plasma into the surface of the target material. In this way, the problems of line-of-sight implantation in ion-beam ion implantation technique can be effectively solved. In addition, the high dose rate and simplicity of the equipment enable the ion implantation a commercially affordable process. In this work, plasma source ion implantation technique was used to improve the wear resistance of Co-cemented WC. which has been extensively used for high speed tools. Nitrogen and carbon ions were implanted using the pulse bias of -602kV, 25 sec and at various implantation conditions. The implanted samples were examined using scanning Auger electron spectroscopy and XPS to investigate the depth distributions of implanted ions and to reveal the chemical state change due to the ion implantation. The implanted ions were found to have penetrated to the depth of 3000$\AA$. The wear resistance of the implanted samples was measured using pin-on-disc wear tester and the wear tracks were examined with alpha-step profilometer.

• Journal of Veterinary Clinics
• /
• v.18 no.1
• /
• pp.48-54
• /
• 2001

The effects of PMSG and/or prostaglandin analogue, cloprostenol, on the prevention of implantation, termination of pregnancy, concentration of plasma progesterone, and Na and K contents of the plasma and uterine fluid were studied in pregnant rats. PMSG 50 or 100 IU concomitant with cloprostenol 90 or 180 mg were administered once on day 3 or 9 of gestation. Rats were autopsied on days 8, 10 or 21 gestation. A single administration of PMSG resulted in increasing the number of corpora lutea, preventing implantation and terminating pregnancy. A single administration of cloprostenol had no effect on the prevention of implantation and termination of pregnancy but was able to induce the termination of pregnancy administering at large doses on day 9. A single administration of PMSG concomitant with cloprostenol ws found to be very increased the number of corpora lutea and to be 100% effective in preventing implantation and to be nearly 100% effective in terminating pregnancy. It is uncommon that a single dose of PMSG 50 IU concomitant with cloprostenol 90 or 180 mg on day 9 was able to maintain the pregnancy at very low rates of 0.3∼5.3%. Concentration of plasma progesterone and Na and K contents of the plasma and uterine fluid were increased or decreased administering PMSG and/or cloprostenol, but had no effect on preventing implantation and terminating pregnancy.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.151-151
• /
• 2012

A new plasma process, i.e., the combination of PIII&D and HIPIMS, was developed to implant non-gaseous ions into materials surface. HIPIMS is a special mode of operation of pulsed-DC magnetron sputtering, in which high pulsed DC power exceeding ~1 kW/$cm^2$ of its peak power density is applied to the magnetron sputtering target while the average power density remains manageable to the cooling capacity of the equipment by using a very small duty ratio of operation. Due to the high peak power density applied to the sputtering target, a large fraction of sputtered atoms is ionized. If the negative high voltage pulse applied to the sample stage in PIII&D system is synchronized with the pulsed plasma of sputtered target material by HIPIMS operation, the implantation of non-gaseous ions can be successfully accomplished. The new process has great advantage that thin film deposition and non-gaseous ion implantation along with in-situ film modification can be achieved in a single plasma chamber. Even broader application areas of PIII&D technology are believed to be envisaged by this newly developed process. In one application of non-gaseous plasma immersion ion implantation, Ge ions were implanted into SiO2 thin film at 60 keV to form Ge quantum dots embedded in SiO2 dielectric material. The crystalline Ge quantum dots were shown to be 5~10 nm in size and well dispersed in SiO2 matrix. In another application, Ag ions were implanted into SS-304 substrate to endow the anti-microbial property of the surface. Yet another bio-application was Mg ion implantation into Ti to improve its osteointegration property for bone implants. Catalyst is another promising application field of nongaseous plasma immersion ion implantation because ion implantation results in atomically dispersed catalytic agents with high surface to volume ratio. Pt ions were implanted into the surface of Al2O3 catalytic supporter and its H2 generation property was measured for DME reforming catalyst. In this talk, a newly developed, non-gaseous plasma immersion ion implantation technique and its applications would be shown and discussed.

• Journal of the Korean Vacuum Society
• /
• v.12 no.S1
• /
• pp.46-48
• /
• 2003

The modification of metal surface by ion implantation with MEVVA ion implanter and thin film deposition with filtered vacuum arc plasma device is introduced in this paper. The combination of ion implantation and thin film deposition is proved as a better method to improve properties of metal surface.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.21 no.5
• /
• pp.34-39
• /
• 2022

The ion implantation technology changes the chemical state of the surface of a material by implanting ions on the surface. It improves the wear resistance, friction characteristics, etc. Plasma ion implantation can effectively reinforce a surface by implanting a sufficient amount of plasma nitrogen ions and using the injection depth instead of an ion beam. As plasma ion implantation is a three-dimensional process, it can be applied even when the surface area is large and the surface shape is complicated. Furthermore, it is less expensive than competing PVD and CVD technologies. and the material is The accommodation range for the shape and size of the plasma is extremely large. In this study, we improved wear resistance by implanting plasma nitrogen ions into a carbide end mill tool, which is frequently used in high-speed machining

• Clinical and Experimental Reproductive Medicine
• /
• v.49 no.3
• /
• pp.168-174
• /
• 2022

Refractory thin endometrium and recurrent implantation failure are among the most challenging infertility-related factors hindering successful pregnancy. Several adjuvant therapies have been investigated to increase endometrial thickness and the pregnancy rate, but the treatment effect is still minimal, and for many patients, these treatment methods can be quite costly and difficult to approach. Platelet-rich plasma (PRP) is an autologous concentration of platelets in plasma and has recently been elucidated as a better treatment option for these patients. PRP is rich in cytokines and growth factors, which are suggested to exert a regenerative effect at the level of the injured tissue. Another advantage of PRP is that it is easily obtained from the patient's own blood. We aimed to review the recent findings of PRP therapy used for patients with refractory thin endometrium and recurrent implantation failure.

• Journal of Korean Vacuum Science & Technology
• /
• v.7 no.2
• /
• pp.45-56
• /
• 2003

A high flux metal plasma pulse ion source, which can simultaneously perform ion implantation and deposition, was developed and tested to evaluate its performance using the prototype. Flux of ion source was measured to be 5 A and bi-polar pulse power supply with a peak voltage of 250 V, repetition of 20 Hz and width of 100 ${\mu}\textrm{s}$ has an output current of 2 kA and average power of 2 kW. Trigger power supply is a high voltage pulse generator producing a peak voltage of 12 kV, peak current of 50 A and repetition rate of 20 Hz. The acceleration column for providing target energy up to ion implantation is carefully designed and compatible with UHV (ultra high vacuum) application. Prototype systems including various ion sources are fabricated for the performance test in the vacuum and evaluated to be more competitive than the existing equipments through repeated deposition experiments.

• Korean Journal of Metals and Materials
• /
• v.46 no.1
• /
• pp.39-43
• /
• 2008

PSII (Plasma Source Ion Implantation) using high density pulsed ICP source was employed to implant oxygen ions in Si wafer. The PSII technique can achieve a nominal oxygen dose of $3 {\times}10^{17}atoms/cm^2$ in implantation time of about 20min. In order to prevent oxidation of SOI layer during high temperature annealing, the wafer was capped with $2,000{\AA}$ $Si_3N_4 $ by PECVD. Cross-sectional TEM showed that continuous $500{\AA}$ thick buried oxide layer was formed with $300{\AA}$ thick top silicon layer in the sample. This study showed the possibility of SOI fabrication using the plasma source ion implantation with pulsed ICP source.

• Journal of the Korean Vacuum Society
• /
• v.4 no.S2
• /
• pp.100-105
• /
• 1995

Nitrogen implantation process has been applied for improvement of wear resistance of Zircaloy-4 fuel cladding materials. Nitrogen was implanted at 120keV to a total dose range of $1\times 10^{17}$ions/$\textrm{cm}^2$ to $1\times 10^{18}$ions/$\textrm{cm}^2$ at various temperatures between $270^{\circ}C$ and $671^{\circ}C$. The microstructure changes by nitrogen implantation were analyzed by XRD and AES and wear behavior was evaluated by performing ball-on-disc type wear testing at various loads and sliding velocities under unlubricated condition. Nitrogen implantation produced ZrNx nitride above $3\times 10^{17}$ions/$\textrm{cm}^2$ as well as heavy dislocations, which resluted in an increase in microhardness of the implanted surface of up to 1400 $H_k$ from 200 $H_k$ of unimplanted substrate. Hardness was also found to be increased with increasing implantation temperature up to 1760 $H_k$ at $620^{\circ}C$. The wear resistance was greatly improved as total ion dose and implantation temperature increased. The effective enhancement of wear resistance at high dose and temperature is believed to be due to the significant hardening associated with high degree of precipitation of Zr nitrides and generation of prismatic dislocation loops.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.06a
• /
• pp.409-410
• /
• 2008