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A size exclusion liquid chromography (HPSEC) method using refractive index (RI) and photodiode array (PDA) detectors and a BASIC calculation program was developed for high molecular weight contaminant determination in the C15 linear paraffin-based cold rolling oil. Eight laboratory standards were analyzed to determine the new HPSEC/RI calibration factor for the C15 linear paraffin rolling oil. Three contaminants and thirteen standard solutions were evaluated to establish calibration curves. The HPSEC/RI/PDA method will quantitatively determine the concentrations of polyisobutylene-based hydrodynamic backup bearing lubricant, mist-applied extreme pressure gear oil for the workroll bearing and antiwear hydraulic oil in the cold rolling oil. Deviations for backup bearing lubricant, workroll bearing lubricant and hydraulic oil are approximately 3%, 4% and 7% of the contaminant concentration, respectively. The BASIC calculation program can assist operators in reducing calculation error and improving s...

A simple processing technology for oxide confined vertical-cavity surface-emitting lasers fabrication is reported in this article. Results of the burn-in test up to the present-day show that the high temperature lifetime of the fabricated devices exceeded 3300 hours. The eye diagrams show that the devices can be modulated up to 10 Gbps.

We report the results of our very large aperture, oxide-confined vertical-cavity surface-emitting lasers (OC-VCSELs). The apertures of the laser-emitting windows are 300 to 500 /spl mu/M in diameter. P-type metal grid lines were also formed within the aperture for better current spreading. A maximum cw optical power of 42.7 mW was measured for a 500 /spl mu/m aperture device.

To understand the functions of a protein, it often requires cloning of the other cellular proteins that interact with it. Several approaches have been used by biologists to clone new genes based on protein-protein interactions, including co-immunoprecipitation, affinity purification, and the yeast two-hybrid system. The yeast two-hybrid cDNA cloning technology is a powerful in vivo protein-protein interaction assay first introduced in 1989 by Fields et al. (Fields and Song 1989; Chien et al. 1991; Chevray and Nathans 1992; Durfee et al. 1993; Zervos et al. 1993; Mendelsohn and Brent 1994). It is based on co-expression of two proteins, X and Y, fused to GAL4 DNA binding domain (GAL4B) and GAL4 transcription activation domain (GAL4A) respectively (Fig. 1 A). If the protein X interacts with the protein Y, the GAL4 transcription activation domain will be brought to the promoter containing the GAL4 DNA binding sites and will activate the transcription of reporter gene HIS3 or lacZ. The two-hybrid system can be used to clone cDNA encoding a novel protein that interacts with a known protein (bait) in yeast. It can also be used to study protein-protein interactions between two known proteins.

Raman spectra have been obtained for the hydrate melts UO 2 (NO 3 ) 2 ·6H 2 O and UO 2 (ClO 4 ) 2 ·7H 2 O and for aqueous solutions of these salts over a wide range of solution composition. There was no evidence of ion-pair formation with uranyl perchlorate but uranyl nitrate formed a weak complex UO 2 NO 3 + with β 1 = 0.15 ± 0.04 at ionic strength 6.25. Complex formation was strongly enhanced by increased ionic strength. Raman depolarization measurements indicated both monodentate and bidentate linkage of nitrate to uranyl. Remarkably large changes in the molar scattering efficiencies of the nitrate modes accompanied the complex formation and suggested that there was considerable electron redistribution in the UO 2 NO 3 + complex.

DuPont ZorbaxTM C8 and NucleosilTM CN columns were used to quantitatively and qualitatively determine ArquadTM 2C-75 additive(1) in the rolling oils and the residual oils extracted from rolled aluminum products using an Indirect Photometric Chromatography (IPC) method. Two negative peaks were shown in the IPC chromatograms for most of the standard samples. The most important thing is that the first negative peak is believed to be an indication of the presence of quaternary ammonium salts. The results obtained from the analyses of several commercial quaternary ammonium salts, amines and a normal paraffin oil in different solvent systems confirm this observation. These standard compounds include dioctadecyldimethylammonium bromide, octadecyltrimethylammonium bromide, cocoamine and dimethylcocoamine. However, the chromatographic condition can only separate quaternary ammonium salts (negative peak #1) from hydrocarbons and amines (negative peak #2). That means the chromatographic condition is unable ...

A Colorado subbituminous coal was reacted with potassium and naphthalene in tetrahydrofuran. This was then alkylated with n-butyl iodide and the solubility in tetrahydrofuran was determined. The solubility was found to be less than in a corresponding reaction with Illinois No. 6 coal. The solubilization of a Colorado subbituminous coal by reacting it with potassium in liquid ammonia, followed by alkylation is discussed. The preliminary results from a reaction of Illinois No. 6 coal with tetrabutylammonium hydroxide and methyl iodide are reported. Reductive acylation of coal is being studied at the present time using trifluoroacetic anhydride as a quenching reagent. /sup 19/F is a candidate for nmr studies and chemical shifts for trifluoroacetyl derivatives of phenols, thiols, and amides indicate that fluorine may be useful as a sensitive probe for reactive species in coal. The effort on donor solvent coal chemistry was directed to the role played by pericyclic reactions in the liquefaction process. The acceptors were reduced by the deuterated donors. The isotopic distribution of the reduction product indicates that free radical processes occur preferentially. Thus, the pericyclic reactions appear to be unimportant at the threshold reaction temperatures of 350 to 425/sup 0/C. The reactions of aromatic ethers withmore » inorganic sulfide at 400/sup 0/C produces thiophenols.« less