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101.
RR Pfister 《Canadian Metallurgical Quarterly》1983,90(6):601-609
Chemical burns of the eye may destroy all of the corneal epithelium and large portions of conjunctival epithelium into the fornices. Restoration of the ocular surface after a chemical burn depends on the centritedal movement of conjunctival epithelial cells and their adherence to the altered corneal stroma. Epithelial movement after a corneal burn is normal for 72 hours after a burn, but persistent epithelial defects thereafter commonly are not resolved until total corneal vascularization occurs. Although this fresh epithelium may be protected by a bandage soft contact lens, more promising and far-reaching approaches may follow epithelial supplementation and even replacement. The link between the health and integrity of the epithelial layer as it relates to the corneal substratum and its cellular constituents remains to be forged. 相似文献
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Zwicker M. Vetro A. Sehoon Yea Matusik W. Pfister H. Durand F. 《Signal Processing Magazine, IEEE》2007,24(6):88-96
Multiview three-dimensional (3-D) displays offer viewing of high-resolution stereoscopic images from arbitrary positions without glasses. This article surveyed different approaches to develop signal processing algorithms for these displays. Such displays consist of view-dependent pixels that reveal a different color according to the viewing angle. Therefore, the left and right eye of an observer sees slightly different images on the screen. This leads to the perception of 3-D depth and parallax effects when the observer moves. Although the basic optical principles of multiview auto-stereoscopy have been known for over a century, only recently displays with increased resolution, or systems based on multiple projectors, have made this approach practical. 相似文献
106.
The 1991 census for England and Wales provides a substantial amount of data on demography, ethnicity, housing tenure, employment status, and other social factors for geographical areas ranging in size from enumeration districts upwards. Many in the health service and in the academic community are making use of the data in the 1991 census. However, users of census data need to be aware of the problems and limitations of these data, which include the format of the data, data modification and suppression, sampling error, and underenumeration. An important innovation of the 1991 census was that the census form included a question on the postcode of respondents; this allowed the Office of Population Censuses and Surveys to produce a postcode-enumeration district look up table which overcomes many of the problems previously encountered in trying to assign postcodes to enumeration districts. The new look up table also includes the grid reference of postcodes, and this will improve the geographical referencing of census data. 相似文献
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H. Sasaki DG K. Yajima N. Yoshida T. Ishida R. Hattori T. Sonoda O. Ishihara S. Takamiya R. Konishi K. Ando 《Journal of Electronic Materials》1996,25(5):559-563
We have investigated the degradation mechanism of Al0.48In0.52As/In0.53Ga0.47As/ InP high electron mobility transistors (HEMTs) using WSi ohmic electrodes. Cross-sectional transmission electron microscopy
(TEM) observation and en-ergy dispersive x-ray (EDX) analysis reveal impurities diffusion of gate electrode (titanium: Ti)
and fluorine (F) in the AlInAs layer after a high temperature (Ta = 170°C operating life test for 500 h. The decrease of drain current (Ids) during life test shows linear dependence on square root of aging time. It suggests that the degradation is controlled by
a diffusion mechanism. Hence, the estimated degradation mechanism of this device is related with decrease of carrier concentration
in the epitaxial layer by these diffused impurities. On the other hand, TEM and EDX show no degradation of WSi/InGaAs interface
after aging. Therefore, the WSi electrode for this type of HEMT demonstrates excellent high stability under the accelerated
operating life test. 相似文献
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