A Volume of Fluid Based Method for Fluid Flows with Phase Change

This paper presents a numerical method directed towards the simulation of flows with mass transfer due to changes of phase. We use a volume of fluid (VOF) based interface tracking method in conjunction with a mass transfer model and a model for surface tension. The bulk fluids are viscous, conducting, and incompressible. A one-dimensional test problem is developed with the feature that a thin thermal layer propagates with the moving phase interface. This test problem isolates the ability of a method to accurately calculate the thermal layers responsible for driving the mass transfer in boiling flows. The numerical method is tested on this problem and then is used in simulations of horizontal film boiling.     

AC floating body effects and the resultant analog circuit issues insubmicron floating body and body-grounded SOI MOSFET's

We report the extensive study on ac floating body effects of different SOI MOSFET technologies. Besides the severe kink and resultant noise overshoot and degraded-distortion in partially depleted (PD) floating body SOI MOSFET's, we have investigated the residue ac floating body effects in fully depleted (FD) floating body SOI MOSFET's, and the different body contacts on PD SOI technologies. It is important to note that there is a universal correlation between ac kink effect and Lorentzian-like noise overshoot regardless of whether the body is floating or grounded. In addition, it was found that third-order harmonic distortion is very sensitive to floating body induced kink or deviation on output conductance due to the finite voltage drop of body resistance. These results provide device design guidelines for SOI MOSFET technologies to achieve comparable low-frequency noise and linearity with Bulk MOSFET's     

Synthetic Studies Toward Bryostatin 1: Preparation of a C(1)-C(16) Fragment by Pyran Annulation

An expeditious assembly of a C₁-C₁₆ subunit of bryostatin 1 is described. A pyran annulation reaction was utilized to form the B-ring by reaction of a hydroxy-allylsilane with a fully elaborated A-ring subunit. This annulation process proceeded with complete diastereoselectivity and in excellent isolated yield despite the presence of potentially sensitive functionality in the A-ring segment.     

Ultrahigh-efficiency power amplifier for space radar applications

This paper describes a broad-band switch mode power amplifier based on the indium phosphide (InP) double heterojunction bipolar transistor (DHBT) technology. The amplifier combines the alternative Class-E mode of operation with a harmonic termination technique that minimizes the insertion loss of matching circuitry to obtain ultrahigh-efficiency operation at X-band. For broad-band Class-E performance, the amplifiers output network employs a transmission line topology to achieve broad-band harmonic terminations while providing the optimal fundamental impedance to shape the output current and voltage waveforms of the device for maximum efficiency performance. As a result, 65% power-added efficiency (PAE) was achieved at 10 GHz. Over the frequency band of 9-11 GHz, the power amplifier achieved 49%-65% PAE, 18-22 dBm of output power, and 8-11 dB gain at 4 V supply. The reported power amplifier achieved what is believed to be the best PAE performance at 10 GHz and the widest bandwidth for a switch-mode design at X-band.     

Certification of morphine-3-β-D-glucuronide in a human urine standard reference material

 The U.S. National Institute of Standards and Technology (NIST) has developed and certified a standard reference material, SRM 2382, for use in testing for bias in the determination of morphine present as a glucuronide in human urine. This SRM consists of three levels of morphine-3-β-D-glucuronide (M-3-G) in lyophilized urine. Two independent hydrolysis procedures, enzymatic and acidic, for quantitative release of morphine were investigated. The results of hydrolysis efficiency from these two procedures agreed well. These two hydrolysis procedures along with two analytical methods developed previously for measurement of free morphine [1] were used to certify M-3-G in SRM 2382. Enzymatic hydrolysis was used with the GC/MS method and acidic hydrolysis was used with LC/MS. The results from these two pairs of methods were in good agreement, and were statistically combined to yield certified values of 209±20, 437±21, and 853±39 ng/mL for morphine, as the free base. Round-robin studies on this material among ten military laboratories demonstrated the suitability of the SRM for its intended purpose. Received: 6 February 1996/Accepted: 29 April 1996     

Measurement and prediction of thermal injury in the retina of the rhesus monkey

The authors measured temperature rises with specially designed microthermocouples in over 60 retinae for various image sizes, wavelengths, and exposure durations. Measured temperatures varied with a standard error of 6 percent, and agreed well with a mathematical model for temperature-time response. Observed injury also compared favorably to that predicted by a rate process model for thermal injury. Suggested rate constants for the eye are A = 1.3 ×1099 1/s, and E = 150 000 cal/M. With these coefficients, predicted threshold injury agreed within a factor of two with experimentally determined injury from 10?8 to 103 s. No difference in threshold temperatures was evident between either macular and paramacular exposures or between wavelengths of 488-647 nm. The model can be used to predict injury in the human eye by substituting absorption coefficients and thickness for the human PE and Ch in the thermal portion of the model.     

Tellurium-implanted N+ layers in GaAs

Ion implantation of Te was investigated as a doping process for the fabrication of submicron n-type layers in GaAs. The implantation was performed with substrates held at 350°C. After implantation, a protective overcoat of AIN or Si₃N₄ was sputtered on the samples to prevent the GaAs from disassociating during anneal (900°C). The electrical characteristics of the n-type implants were then measured. Current-voltage and capacitance-voltage characteristics of implanted diodes indicated that the junctions were linearly graded and that there was no intrinsic layer present after anneal. Sheet resistivity and Hall effect measurements were used to determine the surface carrier concentration and effective mobility in the implanted layers. Ionized impurity profiles extending beyond the implanted junction depth were calculated by matching differential Hall effect data with junction capacitance-voltage data. A peak electron concentration of 7 × 10¹⁸ electrons/cm³ was observed. However, the profiles exhibited penetrating tails that resulted in junction depths being much deeper than the LSS range theory would predict.     

High-power, 4 W pulsed, grating-coupled surface-emitting laser

AlGaAs surface-emitting lasers fabricated with second-order grating, distributed Bragg reflector regions for output coupling and feedback are demonstrated to operate at high output powers. Powers of 1.75 and 4 W pulsed are reported for single gain section and three gain section lasers.<>