The design and optimization of high-performance, double-polyself-aligned p-n-p technology

The device design and performance of double-poly self-aligned p-n-p technology, featuring a low-resistivity p⁺ subcollector, thin p-epi, and boron-doped poly-emitter are described. Device isolation is provided by deep and shallow trenches which reduce the collector-to-substrate capacitance while maintaining a high breakdown voltage (⩾40 V). By utilizing a shallow emitter process in conjunction with an optimized arsenic-base implant, devices with emitter-base junction depths as shallow as 20 nm and base widths of less than 100 nm were obtained. Cutoff frequencies of up to 27 GHz were obtained, and the AC performance was demonstrated by an NTL-gate delay of 36 ps and an active-pull-down (APD) ECL-gate delay of 20 ps. This high-performance p-n-p technology was developed to be compatible with existing double-poly n-p-n technologies. The matching speed of p-n-p devices opens up new opportunities for high-performance complementary bipolar circuits     

Multilevel-spiral inductors using VLSI interconnect technology

A multilevel-spiral (MLS) inductor structure for implementation in VLSI interconnect technology is presented. Inductances of 8.8 and 32 nH and maximum quality-factors (Q) of ~6.8 and 3.0, respectively, are achieved in a four-level metal BiCMOS technology, with four turns at each of the two or four stacked spiral coils and with an area of 226×226 μm². The comparison of the MLS inductors to different single-level-spiral (SLS) control devices shows that a MLS inductor provides the same inductance at ~50% dc resistance, but the maximum Q is typically measured at a lower frequency and the self-resonance frequency is reduced due to a high inter-wire capacitance     

Influence of Tower Shadow and Wind Turbulence on the Performance of Power System Stabilizers for DFIG-Based Wind Farms

The aim of the paper is to demonstrate the way in which mechanical power variations, due to tower shadow and wind turbulence, influence control performance of power system stabilizer (PSS) loops for doubly-fed induction generators (DFIGs). The PSS auxiliary loops are applied on a specific DFIG control scheme, the flux magnitude and angle controller (FMAC). However, since the PSS signal is applied at the output of the basic controller, the PSS performance characteristics displayed are deemed typical for DFIG control schemes in general. The relative capabilities of PSS controllers based on stator power, rotor speed, and network frequency, when the DFIG turbine is subjected to aerodynamic torque variations, are investigated via simulation studies. A two-generator aggregate model of a wind farm is introduced, which enables the influence of tower shadow and wind turbulence on both an individual turbine and on the overall wind farm itself to be assessed.     

Lipid compositional changes in calves fed excess iodine

Calves were fed milk replacer containing .57, 10, or 200 ppm iodine (from ethylenediaminedihydriodide) to determine the effects of excess dietary iodine on composition of lipids in blood plasma, liver, and heart. High iodine intakes had no effect on plasma total lipids or lipid classes, but caused lipid class concentration changes in liver and heart. Both 10 and 200 ppm iodine increased concentration of liver phosphatidylethanolamine and heart phosphatidylcholine, cholesterol, and total lipids, and the 200 ppm intake also increased concentration of liver phosphatidylcholine, total lipids, and heart phosphatidylethanolamine. Both iodine treatments tended to increase all the other minor lipid classes in liver and heart as well. Both 10 and 200 ppm iodine treatments increased some of the n-3 polyunsaturated fatty acids in the major phospholipids of plasma, liver, and heart. For the preruminant calf, liver and heart may be more useful than blood plasma for indicating excess iodine effects on lipid metabolism.     

Verifying SRAM designs

Verifying the design and simulation of 256 K SRAM relies on measurements of waveforms on internal nodes along a critical path. A technique for producing accurate measurements of these waveforms using electron-beam probing is described. Comparisons of measured and simulated waveforms at several points on a chip are presented. It is shown that the measured signals agree with the simulation in regard to risetime, amplitude, and time delay along the path, thereby verifying the correctness of the device and circuit models used in the simulation. Slight deviations from the predicted time delay are the result of circuit design and process variations     

Radiology in primary hyperaldosteronism

Autonomous hypersecretion of aldosterone (primary hyperaldosteronism) is caused by either hyperplasia (usually bilateral) or an adenoma (frequently unilateral) of the adrenal cortex. Systemic hypertension due to an aldosteronoma is a potentially curable condition through surgical extirpation of the offending organ. In our experience with 37 patients clinically suspected to have primary hyperaldosteronism, radiological methods contributed significantly in preoperative diagnosis. These included (1) selective bilateral adrenal vein catheterization and blood sample collection, (2) adrenal venography, and (3) radioisotope adrenal scan. Unilateral hyperfunction could be accurately detected by the aldosterone assays from the collected samples. When adrenal venography was technically satisfactory, a nodule or aggregate of nodules measuring at least 7 mm and located on the margin of the gland or 1.5 cm or more in diameter when located in the center of the gland were readily identified. Enlarged adrenal gland on venography, in itself, was not a dependable index of a hyperfunctioning gland. Presence of a higher uptake on one side on the radioisotope adrenal scan did not always indicate the hyperfunctioning gland, but lack of lateralization of adrenal hyperfunction was more accurately predicted on the radioisotope scan than by venography. Four histopathological patterns were recognized in the surgically removed adrenal glands, but no correlation between these patterns and clinical behavior or postoperative course was found.     

The specificity of split renal membranes in hereditary nephritis

This study was undertaken to assess the specificity of split renal basement membranes in hereditary nephritis (HN). Thirteen specimens from eight patients with HN were mixed in a random fashion with specimens from control patients with either idiopathic nephrotic syndrome or various forms of glomerulonephritis and with specimens from patients with benign recurrent hematuria (BRH). Each biopsy specimen was scored for splitting of glomerular basement membranes (GBMs). Control and BRH specimens contained focal splitting in the GBMs; the biopsy specimens from HN patients had widespread lesions. Evaluation of split GBMs is useful in differentiating patients with HN from those with BRH and other renal diseases that may be confused with HN.     

Systemic methotrexate toxicity. A pharmacological study of its occurrence after intrathecal administration in a patient with renal failure

Methotrexate pharmacokinetic studies, performed on a patient with renal impairment who had toxic effects following 20 mg/sq m of intrathecally administered methotrexate, demonstrated prolonged serum concentrations of the drug, which accounted for the condition. After the return of normal renal function, pharmacokinetic studies were repeated following the same dose and route of administration of methotrexate. On this occasion there was a rapid clearance of serum methotrexate below toxic levels.     

The significance of focal glomerular sclerosis in children who have nephrotic syndrome

This study was undertaken to learn the significance of focal glomerular sclerosis in children who have nephrotic syndrome. Tissue obtained by percutaneous renal biopsy 10-15 years previously was re-examined. Initially, two of the 29 biopsy specimens contained focal segmental hyalinosis or sclerosis and five of the 29 had focal glomerular obsolescence. The paraffin blocks were serially sectioned and examined. Following this procedure, seven of the 29 biopsies had focal segmented hyalinosis and 16 of the 29 had focal glomerular obsolescence. The percentages of focal segmental hyalinosis and focal glomerular obsolescence were recorded. Only those patients whose focal segmental hyalinosis exceeded 2% progressed to renal failure. Age-matched autopsy material from patients dying without renal dysfunction was used as a control. Focal glomerular sclerosis was seen in 75.8% of the control specimens, although few glomeruli within each specimen were involved. Focal glomerular sclerosis may be found normally; it may be found in nephrotic children who do not develop renal failure. The quantification of sclerotic lesions may be of prognostic significance in childhood nephrosis.