Study of bonding methods for flip chip and beam leaded devices

The results are presented of a comprehensive study and evaluation for the bonding of flip chip and beam leaded devices onto hybrid microcircuit substrates used in high reliability space applications. The program included the evaluation of aluminum flip chips, solder (silver/tin) bump chips, gold beam leaded devices, and aluminum beam leaded devices

Examining the Impact of Parental Socialization on the Coping Styles of Black Graduate Students Faced with Microaggressions

This article explores case examples of two graduate students who endure microaggressions from their math professor at a predominantly White university. The role that parental socialization plays in how these students developed their racial identities and the coping strategies they employed, is analyzed through the lens of Triple Quandary theory (Boykin and Toms 1 985). Findings from this investigation suggest that parental socialization is critical in preparing these students to cope with and respond to microaggressions in protective and adaptive ways. This paper illuminates coping styles, although divergent, that served these graduate students\u27 needs and protected their individual racial identities. Further, the support these students received from their faculty advisor who is also Black, exemplifies the importance of mentorship and advocacy from faculty of color to Black college students\u27 success. Direction for continuity in parental teachings for K-12 and university level educators are discussed

NASA micromin computer Monthly progress letter, Jan. 1967

Microminiature circuit development for flight control computer

Soft X-ray Emission from the Spiral Galaxy NGC 1313

The nearby barred spiral galaxy NGC 1313 has been observed with the PSPC instr- ument on board the ROSAT X-ray satellite. Ten individual sources are found. Three sources (X-1, X-2 and X-3 [SN~1978K]) are very bright (~10^40 erg/s) and are unusual in that analogous objects do not exist in our Galaxy. We present an X-ray image of NGC~1313 and \xray spectra for the three bright sources. The emission from the nuclear region (R ~< 2 kpc) is dominated by source X-1, which is located ~1 kpc north of the photometric (and dynamical) center of NGC~1313. Optical, far-infrared and radio images do not indicate the presence of an active galactic nucleus at that position; however, the compact nature of the \xray source (X-1) suggests that it is an accretion-powered object with central mass M >~ 10^3 Msun. Additional emission (L_X ~ 10^39 erg/s) in the nuclear region extends out to ~2.6 kpc and roughly follows the spiral arms. This emission is from 4 sources with luminosity of several x 10^38 erg/s, two of which are consistent with emission from population I sources (e.g., supernova remnants, and hot interstellar gas which has been heated by supernova remnants). The other two sources could be emission from population II sources (e.g., low-mass \xray binaries). The bright sources X-2 and SN~1978K are positioned in the southern disk of NGC~1313. X-2 is variable and has no optical counterpart brighter than 20.8 mag (V-band). It is likely that it is an accretion-powered object in NGC~1313. The type-II supernova SN~1978K (Ryder \etal 1993) has become extra- ordinarily luminous in X-rays $\sim$13 years after optical maximum.Comment: to appear in 10 Jun 1995 ApJ, 30 pgs uuencoded compressed postscript, 25 pgs of figures available upon request from colbert, whole preprint available upon request from Sandy Shrader ([email protected]), hopefully fixed unknown problem with postscript fil

Citation searching and bibliometric measures: Resources for ranking and tracking

The avenues to evaluate citation tracking and journal ranking have greatly increased in the past six years. Bibliometrics, the application of mathematical and statistical analysis to books, journals, and other publications, 1 allows us to choose journal collections, assist with applications for research funding, evaluate journal status, and find significant contributors in a subject area. Most importantly, the expertise librarians have in this area can be used to help our faculty prove their scholarly contribution and achieve success in their tenure process. \u

HST NICMOS imaging of z~2, 24 micron-selected Ultraluminous Infrared Galaxies

We present Hubble Space Telescope NICMOS H-band imaging of 33 Ultraluminous Infrared Galaxies (ULIRGs) at z~2 that were selected from the 24 micron catalog of the Spitzer Extragalactic First Look Survey. The images reveal that at least 17 of the 33 objects are associated with interactions. Up to one fifth of the sources in our sample could be minor mergers whereas only 2 systems are merging binaries with luminosity ratio <=3:1, which is characteristic of local ULIRGs. The rest-frame optical luminosities of the sources are of the order 10^10-10^11 L_sun and their effective radii range from 1.4 to 4.9 kpc. The most compact sources are either those with a strong active nucleus continuum or those with a heavy obscuration in the mid-infrared regime, as determined from Spitzer Infra-Red Spectrograph data. The luminosity of the 7.7 micron feature produced by polycyclic aromatic hydrocarbon molecules varies significantly among compact systems whereas it is typically large for extended systems. A bulge-to-disk decomposition performed for the 6 brightest (m_H<20) sources in our sample indicates that they are best fit by disk-like profiles with small or negligible bulges, unlike the bulge-dominated remnants of local ULIRGs. Our results provide evidence that the interactions associated with ultraluminous infrared activity at z~2 can differ from those at z~0.Comment: ApJ, in press. Document revised to match the journal versio

Cancer Immune Evasion Through Loss of MHC Class I Antigen Presentation

Major histocompatibility class I (MHC I) molecules bind peptides derived from a cell\u27s expressed genes and then transport and display this antigenic information on the cell surface. This allows CD8 T cells to identify pathological cells that are synthesizing abnormal proteins, such as cancers that are expressing mutated proteins. In order for many cancers to arise and progress, they need to evolve mechanisms to avoid elimination by CD8 T cells. MHC I molecules are not essential for cell survival and therefore one mechanism by which cancers can evade immune control is by losing MHC I antigen presentation machinery (APM). Not only will this impair the ability of natural immune responses to control cancers, but also frustrate immunotherapies that work by re-invigorating anti-tumor CD8 T cells, such as checkpoint blockade. Here we review the evidence that loss of MHC I antigen presentation is a frequent occurrence in many cancers. We discuss new insights into some common underlying mechanisms through which some cancers inactivate the MHC I pathway and consider some possible strategies to overcome this limitation in ways that could restore immune control of tumors and improve immunotherapy

Hydrogen adsorption and cohesive energy of single-walled carbon nanotubes

Hydrogen adsorption on crystalline ropes of carbon single-walled nanotubes (SWNT) was found to exceed 8 wt.%, which is the highest capacity of any carbon material. Hydrogen is first adsorbed on the outer surfaces of the crystalline ropes. At pressures higher than about 40 bar at 80 K, however, a phase transition occurs where there is a separation of the individual SWNTs, and hydrogen is physisorbed on their exposed surfaces. The pressure of this phase transition provides a tube-tube cohesive energy for much of the material of 5 meV/C atom. This small cohesive energy is affected strongly by the quality of crystalline order in the ropes