Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1990-1994  (4)
  • 1991  (4)
Source
Material
Years
  • 1990-1994  (4)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Excimer laser ablation of ferrites (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 2072-2075 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Laser etching of ferrites was previously done by scanning a focused continuous-wave laser beam on a ferrite sample in a chemical environment. We study the phenomenon of photo-ablation of Ni-Zn or Mn-Zn ferrites by pulsed 248-nm KrF excimer laser irradiation. A transfer lens system is used to project a grating pattern of a mask irradiated by the pulsed KrF laser onto the ferrite sample. The threshold fluence for ablation at the ferrite surface is about 0.3 J/cm2. A typical fluence of 1 J/cm2 is used. The etched grooves produced are typically 20–50 μm wide, with depths achieved as deep as 70 μm . Groove straightness is good as long as a sharp image is projected onto the sample surface. The wall angle is steeper than 60 degrees. Scanning electron microscopy of the etched area shows a "glassy'' skin with extensive microcracks and solidified droplets being ejected that is frozen in action. We found that this skin can be entirely removed by ultrasonic cleaning. A fairly efficient etching rate of about 10 nm/pulse for a patterned area of about 2 mm×2 mm is obtained at a fluence of 1 J/cm2. This study shows that projection excimer laser ablation is useful for micromachining of ferrite ceramics, and indicates that a hydrodynamic sputtering mechanism involving droplet emission is a cause of material removal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348915
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Efficient pulsed laser removal of 0.2 μm sized particles from a solid surface (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 2217-2219 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Laser cleaning with pulsed ultraviolet and infrared lasers is successfully employed to remove particulate contamination from silicon wafer surfaces and from delicate lithography membrane masks. Particulate material investigated include latex, alumina, silicon, and gold. Gold particles as small as 0.2 μm can be effectively removed. This new and highly efficient laser cleaning is achieved by choosing a pulsed laser with short pulse duration (without causing substrate damage), and a wavelength that is strongly absorbed by the surface; the removal efficiency is further enhanced by depositing a liquid film of thickness on the order of micron on the surface just before the pulsed laser irradiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.104931
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Transient absorption and fluorescence spectroscopy in fused silica induced by pulsed KrF excimer laser irradiation (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 3369-3371 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have carried out in situ transient absorption and fluorescence spectroscopy measurements in two "wet''(OH content ∼0.1%) fused silica samples (Suprasil II from Heraeus Amersil and P-30 from Shin-Etsu Quartz Product) during KrF laser irradiation. Both samples exhibit an absorption peak at 210 nm corresponding to the E' center. For Suprasil II, there is also a 265 nm absorption peak, and both peaks increase with the number of irradiated pulses showing little relaxation after the laser was turned off. The region irradiated with three million pulses at 400 mJ/cm2 fluence ten months ago has a residual absorption of about 10%/cm at 210 nm. On the other hand, the P-30 shows a rapid increase in the 210 nm absorption in both the unirradiated and previously irradiated regions during the initial irradiation and levels off after a few thousand pulses. There is no residual absorption at the spot irradiated for 63 million pulses ten months ago. However, the initial rate of increase in the previously irradiated spot is twice as high as compared to the unirradiated spot. This suggests the density of the precursor state for the E' center is higher in the previously irradiated region. The fluorescence intensity at 650 nm increases with the induced absorption for Suprasil II, but is almost independent of the number of irradiation pulses in P-30. The quasilinear repetition-rate dependence suggests the fluorescence is transient in nature and relaxes partially between successive laser pulses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.105703
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Modulation of clonal progression in B16F1 melanoma cells (1991)
    Springer
    Clinical & experimental metastasis 9 (1991), S. 151-162 
    Details
    ISSN: 1573-7276
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have examined the effects of the microenvironment on the frequency and generation of metastatic variant cells in both parental B16F1 melanoma cells and nascent clones. The metastatic abilities of cultured B16F1 cells were tested after a period of growth in the presence or absence of a second cell population separated from each other by a transwell membrane (0.45μm pore size). The first population is defined as the ‘responder’ cells and the second as the ‘stimulator’ cells. We found that the presence of 105 B16F1 stimulator cells during the growth of responder B16F1 cells from ∼104 to ∼106 cells resulted in cells with an increased metastatic phenotype (〉 8-fold increase in median number of lung tumors relative to untreated B16F1 parental cells). The presence of stimulator cells also increased the metastatic phenotype of nascent clones, which were grown to a population size of 〈106 cells, suggesting that the rate of generation of metastatic variants of the responder B16F1 clones was affected by the stimulator cells. Other cell lines, including highly metastatic B16F10 and BL6 melanoma cells, and KHT35-L1 fibrosarcoma cells, were effective stimulator cells when as few as 104 cells were added to transwells. In addition, normal immortalized NIH 3T3 cells were effective stimulator cells only at 105 cells/transwell. The cell density at which untreated parental B16F1 cells were harvested (3×103−3 × 105 cells/cm2) did not affect the median number of lung tumors significantly. These results suggest that factors released from both tumor and immortalized normal cells can modulate epigenetic changes in the metastatic phenotype of B16F1 melanoma cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01756386
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...