• Current Applied Physics
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• 제18권11호
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• pp.1368-1374
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• 2018

In this paper, forced vibration was used to regulate the droplet migration, fully recording the transient migration of droplets on a micro-textured substrate under the resonance frequency by a high-speed camera. The influence of resonance frequency and dynamic migration characteristics of droplets on the solid micro-texture surface under lateral vibration were researched. The experiment demonstrates that the driving force is caused by the difference between the left and right contact angles made the droplet oscillate and migrate, and as time t increases, the left and right contact points are periodically shifted and the amplitude of migration increases. Therefore, based on the droplet migration behavior and its force balance mechanism, a spring vibration model of migration behavior of the vibrating droplet micro unit was set up to predict the complete trajectory of its migration on a solid surface. The calculation results show that the theoretical displacement is less than the experimental displacement, and the longer the time, the larger the difference. Affected by the vibration, part of the droplet permeates through the micro-texture, resulting in the droplet losing height and the contact angle becoming smaller as well. While the other part of droplet overcomes the internal surface tension to migrate.

• 한국표면공학회지
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• 제47권2호
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• pp.63-67
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• 2014

As the demand for fine-pitch FPCB (Flexible Printed Circuit Board) increases, so do the number of applications of sputtered FCCL (Flexible Copper Clad Laminate). Furthermore, as the width between the circuit patterns decreases, greater defects are observed in the migration phenomenon. In this study we observed changes in ion migration in real circuit-pattern width using sputtered FCCL. We found that as the applied voltage and residue thickness of the NiCr seeds increase, ion migration occurs faster. If the NiCr seed layer thickens due to a high cathode power and long deposition time while being sputtered, the NiCr will form a residue that quickly becomes a factor for incurring ion migration.

• 지구물리와물리탐사
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• 제21권1호
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• pp.41-53
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• 2018

전통적인 탄성파 탐사 자료처리 분야에서 겹반사파(multiple)는 잡음으로 취급되어 제거한 후 자료처리를 수행한다. 그러나 최근 겹반사파를 잡음이 아닌 하나의 신호로 인식하고 이를 영상화에 이용하는 연구가 많이 이루어지고 있다. 겹반사파는 일차 반사파(primary reflection)가 도달하지 못하는 지점까지 도달할 수 있어 적은 수의 송신원과 수신기로도 더 넓은 범위를 영상화 할 수 있다. 이를 검증하기 위해 본 연구에서는 영상화 기법 중 하나인 거꿀시간 참반사 보정(reverse-time migration)을 이용하여 겹반사파 자료를 영상화한 후 일차 반사파를 사용한 전통적인 거꿀시간 참반사 보정 결과와 비교하였다. 겹반사파를 독립적으로 사용하기 위해 자유면 기인 겹반사파 제거(surface-related multiple elimination; SRME)기법을 사용해 탄성파 자료에서 겹반사파를 분리하였다. 수치 예제를 통해 겹반사파를 이용한 참반사 보정 결과가 일차 반사파를 이용한 전통적인 참반사 보정 결과보다 더 넓은 범위를 영상화 할 수 있음을 확인하였고, 특히 천부 지층에서 두드러진 효과가 나타나는 것을 알 수 있었다. 또한 겹반사파를 이용한 참반사 보정은 자료취득 흔적(acquisition footprint)에 의한 영상 왜곡이 제거됨을 확인할 수 있었다.

• Tribology and Lubricants
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• 제15권4호
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• pp.335-342
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• 1999

Corrosion of the disk has been an ongoing concern for the manufacturers of hard disk drives. With the advent of magnetoresistive (MR) head, very low levels of corrosion and contamination become more critical since the raised defects and corrosion products on the disk surface-anything that heats the MR sensor due to the contact-can distort the output signal of the head. This phenomenon is called as thermal asperity. In this paper, the effect of corrosion as a form of Co migration on the occurrence of thermal asperity in MR drives was investigated. The corrosion test at high temperature (60$^{\circ}C$) and high relative humidity (80%) was emphasized in this study and the testing results at ambient condition were compared. The corrosion on the disks was characterized as the amount of Co ion migration using an ion chromatography (IC) and a time-of-flight secondary ion mass spectroscopy (TOF-SIMS). It is proved that corrosion on the disk surface after storage testing is closely correlated to the amount of Co ions migration from the magnetic layer to disk surfaces and higher Co migration causes more thermal asperities in the drive. In order to reduce Co migration, several methods such as burnishing process and structure of the carbon overcoat were investigated. It is found that the hydrogenated carbon overcoat shows the least Co migration among different types of overcoat layer. However, the most effective way to reduce Co migration is the application of Cr layer between the overcoat and the magnetic alloy layer.

• 전자공학회논문지A
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• 제30A권6호
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• pp.1-7
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• 1993

After the 1%S-Al metal is deposited, a thin oxide is formed thereon. Then, a single charged Argon(Ar$^{+}$) is ion implanted into the oxide layer, thereby causing the metal grain in the upper surface of the metal layer to become amorphous. Consequently, the grain size will be reduced and the rough surface of the metal layer flattened. However, the remainder of the metal layer beneath the upper surface thereof will still exhibit large grain size and low resistance, because the Argon ion is only implanted to characterized by a dual-sized grain structure which served to reduce interlayer stress, thereby decreasing the rate of stress migration, and to lower the resistivity of the metal line, thereby enhancing the electromigration characteristic thereof. Experiments have shown that the metal line exhibits a metal migration rate which is approximately 700% less than the control group and a standard deviation which is approximately 200% less than these group.p.

• Bulletin of the Korean Chemical Society
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• 제19권2호
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• pp.170-174
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• 1998

Migration properties of antidegradants to the surface in NR vulcanizates containing carbon black of 30, 50, and 70 phr were studied using the migration-generating equipment with a vacuum technique. The migration was carried out at 60, 80, and 100 ℃ for 20 h. BHT, IPPD, HPPD, and wax were used as migrants. IPPD migrates faster than the other migrants. Amounts of BHT, IPPD, and HPPD that migrated at 60 and 80 ℃ decrease as the content of carbon black in the vulcanizate increases. Migrations of antidegradants in the NR vulcanizate containing carbon black of 50 phr are faster than those containing carbon black of 30 and 70 phr at 100 ℃. Although n-C23H48 is heavier than HPPD, it migrates faster than HPPD and even faster than BHT at 100 ℃. Influencing factors of carbon black on the migrations are its porous structure and polar functional groups on the surface.

• ALGAE
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• 제25권3호
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• pp.133-140
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• 2010

Using chlorophyll fluorescence, the vertical migration of benthic diatoms responding to light intensity and affected by sediment grain size was studied. Minimal fluorescence ($F_o$) of surface sediment was measured by imaging pulse amplitude modulated (Imaging-PAM) fluorometer, and used to monitor diatom biomass variation in surface sediments. The test diatoms, Amphora coffeaeformis (C. Agardh) K$\ddot{u}$tzing and Cylindrotheca closterium (Ehrenberg) Reimann & Lewin, migrated to the sediment surface under irradiance from 50 to 500 ${\mu}mol$ photons $m^{-2}s^{-1}$. However, the diatoms exhibited no evident increase of surface biomass under dark conditions, and even showed slightly decrease of surface biomass under irradiances over 1,000 ${\mu}mol$ photons $m^{-2}s^{-1}$. The light intensity inducing the maximum surface migration of A. coffeaeformis was 100 ${\mu}mol$ photons $m^{-2}s^{-1}$, while the light intensity producing the same effect for C. closterium was 250 ${\mu}mol$ photons $m^{-2}s^{-1}$. C. closterium showed higher motility than A. coffeaeformis. Faster diatom surfacing was observed in larger grain size sediments (125-335 ${\mu}m$) than smaller ones (63-125 ${\mu}m$). This study confirmed the significant influence of light as a main triggering factor behind migration, indicated the distinct effect of different sediment grain size, and highlighted the species-specific migratory ability.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3715-3721
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• 2013

In this study, the behavior of cells on the modified surface, and the correlation between the modified substrates and the response of cells is described. A close-packed layer of nano-sized silica beads was prepared on a coverslip, and the adhesion, proliferation, and migration of BALB/3T3 fibroblast cells on the silica layer was monitered. The 550 nm silica beads were synthesized by the hydrolysis and condensation reaction of tetraethylorthosilicate in basic solution. The amine groups were introduced onto the surfaces of silica particles by treatment with 3-aminopropyltrimethoxysilane. The close-packed layer of silica beads on the coverslip was obtained by the reaction of the amine-functionalized silica beads and the (3-triethoxysilyl)propylsuccinic anhydride treated coverslip. BALB/3T3 fibroblast cells were loaded on bare glass, APTMS coated glass, and silica bead coated glass with the same initial cell density, and the migration and proliferation of cells on the substrates was investigated. The cells were fixed and stained with antibodies in order to analyze the changes in the actin filaments and nuclei after culture on the different surfaces. The motility of cells on the silica bead coated glass was greater than that of the cells cultured on the control substrate. The growth rate of cells on the silica bead coated glass was slower than that of the control. Because the close-packed layer of silica beads gave an embossed surface, the adhesion of cells was very weak compared to the smooth surfaces. These results indicate that the adhesion of cells on the substrates is very important, and the actin filaments might play key roles in the migration and proliferation of cells. The nuclei of the cells were shrunk on the weakly adhered surfaces, and the S1 stage in which DNA is duplicated in the cell dividing processes might be retarded. As a result, the rate of proliferation of cells was decreased compared to the smooth surface of the control. In conclusion, the results described here are very important in the understanding of the interaction between implanted materials and biosystems.

• 멤브레인
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• 제7권3호
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• pp.150-156
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• 1997

입자의 정밀여과에 있어 임계플럭스의 이론치를 계산하기 위해 확산(diffusion), 횡방향이동(lateral migration), 전단유도확산(shear induced diffusion), 그리고 입자의 정전기적 반발력에서 기인하는 상호작용에 의한 상승이동(interation enhanced migration) 등의 입자의 역전달 이동을 고려하였다. 보통의 여과조건에서 제타전위의 절대치가 20~40mV이고 직경이 0.1$\mu{m}$~10$\mu{m}$인 입자의 경우 상호작용에 의한 이동이 가장 중요한 역전달 메카니즘이었다. 입자크기에 따라 계산된 임계플럭스값을 실험적으로 확인하기 위해 다양한 크기를 갖는 구형인 적철광(hematite)입자를 합성하여 여과실험을 수행하였다. 이 실험치는 역전달 이론에 의해 예측된 플럭스의 이론치와 비교적 잘 일치하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.279-279
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• 2012

In order to estimate the average migration lengths of $H_3O^+$ ions in amorphous ice, we conducted experiments of reactive ion scattering (RIS), low energy sputtering (LES), and reflection absorption IR spectroscopy (RAIRS) with an ultra-high vacuum (UHV) chamber. Dopped water-ice films were grown on the clean surface of Ru single crystal and analyzed with RIS, LES and RAIRS methods. The population changes of probe molecules, which were buried at a controlled distance from the surface, were monitored by those methods so that we can mesure the migration efficiencies. From the measured efficiencies, we evaluated the average migration lengths. This result is expected to give the information about the dynamics of proton in water-ice film.