A double-recessed Al0.24GaAs/In0.16GaAspseudomorphic HEMT for Ka- and 𝒬-band power applications

A double-recessed 0.2-μm-gate-length pseudomorphic HEMT (PHEMT) has been demonstrated with 500 mW of output power (833 mW/mm of gate periphery), 6-dB gain, and 35% power-added efficiency (PAE) at 32 GHz. At 44 GHz, the device exhibited 494 mW of output power (823 mW/mm), 4.3-dB gain, and 30% PAE. This level of performance is attributed to excellent MBE material, optimized epitaxial layer design, and the use of individual source vias and of double recess with tight channel dimensions. Excellent 3-in-wafer uniformity was also observed: DC yield was greater than 95% and the interquartile range for all DC parameters was less than 20% of the median value (most are significantly lower)     

Patient and therapy process variables relating to dropout and change in psychotherapy.

Investigated the relationship between pretherapy patients and process variables and change in 91 19–54 yr old adults who received psychotherapy from 26 trainees at a university teaching hospital. Pretherapy measures included Rotter's Internal–External Locus of Control Scale, the Eysenck Personality Inventory, and the SCL-90 (Revised). Upon termination of therapy, Ss completed the SCL-90, the Barrett-Lennard Relationship Inventory—Form OS64, and a personal evaluation form; therapists completed a psychotherapy process inventory and a discharge summary. Results indicate that process variables rather than preexisting S traits were the best predictors of outcome. Therapist ratings of Ss' involvement in therapy were the best single predictor of symptomatic change. Variables differentiating dropouts from remainers were also investigated. Few outcome differences were observed between Ss who remained in and Ss who dropped out of therapy. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Radiation-Induced Hole Trapping and Interface State Characteristics of Al-Gate and Poly-Si Gate MOS Capacitors

Using the techniques of thermally stimulated current and high-frequency C-V measurements, the device processing dependence of radiation-induced hole traps and interface states in MOS capacitors has been investigated. It was found that the fabrication of poly-Si gates caused all investigated gate oxides to resemble those grown by pyrogenic techniques. The role of postoxidation annealing (POA) in hole trap formation and interface state generation was investigated. The measurements imply that POA causes a "weakening" of bonds in SiO2 which can become hole traps, and, in the presence of OH, lead to the annihilation of certain types of hole traps while generating new types of hole traps and interface states. Possible models and interface state distributions are discussed. Midgap voltage shifts were found not to be generally valid measures of hole trapping in these MOS devices.     

Functional outcome of below-knee amputation in peripheral vascular insufficiency. A multicenter review

A retrospective functional outcome study was performed on 299 patients treated with below-knee amputations for peripheral vascular disease during a three-year period in six Veterans Administration special amputee centers. Sixty-one percent of the patients were diabetic, and 25% were previously unilateral amputees. Surgery was performed with a long posterior flap in 92.3%, sagittal flaps in 20%, and guillotine open technique in 5.7%. Wound management was accomplished with rigid plaster dressings in 75.3%, pneumatic compression dressing in 14%, and soft dressings in 10.7%. At follow-up evaluation one to two years later, 36.1% had died. Thirteen percent suffered wound complications, with 6.7% requiring revision to a more proximal amputation level. Eighty-seven percent of community ambulators maintained their ambulatory status. A comparable percentage maintained their ability to walk with a prosthesis.     

Thermally Stimulated Current Measurements on Irradiated MOS Capacitors

Thermally stimulated current and high frequency C-V measurements have been used to study the properties of hole traps near the Si-SiO2 interface in irradiated silicon MOS capacitors. Pre-irradiation bias-temperature (BT) instabilities, both for negative and positive bias, were observed in non-ion-contaminated samples. The activation energy for BT instabilities for both polarities is ~1.0 eV independent of radiation hardness. Distributions of activation energies for trapped holes produced by Co60 irradiation are centered at ~0.85 and ~1.3 eV. The ~0.85 eV distribution occurs only if Na+ was previously present at the Si-SiO2 interface. The ~1.3 eV distribution consists of multiple overlapping distributions. Mechanisms that could lead to these distributions of activation energies are discussed.     

An AlGaAs/InGaAs pseudomorphic high electron mobility transistorwith improved breakdown voltage for X- and Ku-bandpower applications

The authors determined that RF drain current degradation is responsible for the poor power performance of wide-recessed pseudomorphic high-electron-mobility transistors (PHEMTs). A model based on surface states was proposed to explain this phenomenon, which then led to the use of charge-screen layers and a double-recessed gate process to suppress surface effects. Combined, these two modifications increased the device's gate-drain reverse breakdown voltage without causing a degradation in the transistor's RF drain current. This allowed the simultaneous achievement of high power-added efficiency and high power density which established a new performance record for power PHEMTs at X- and Ku-bands. Delay time analysis of single- and double-recessed PHEMTs revealed that the benefit of a larger breakdown voltage in the latter device design came at the cost of a larger drain delay time. Drain delay accounted for 45% of the total delay when the 0.35-μm double-recessed PHEMT was biased at V_ds=6 V     

Client–therapist value similarity and psychotherapy outcome: A microscopic analysis.

Examined the association between patient–therapist pretreatment value similarity and subsequent improvement in 45 nonpsychotic psychiatric outpatients (aged 19–54 yrs) who were randomly assigned to 22 therapists. Pre-assignment assessment of similarity in 36 value dimensions on the Rokeach Value Survey was investigated to determine how the dimensions influenced symptomatic and global changes in the therapy process. Treatment outcome was assessed both by patient and therapist reports, and the SCL-90 was used to evaluate pre- to posttreatment symptom change on 9 symptom dimensions. In addition, therapists were asked to complete a subjective rating of improvement at the end of treatment. The results indicate that a complex pattern of similarity and differences in specific values promoted maximal improvement. Moreover, specific improvement measures were influenced differently by various patient–therapist value patterns. Generally, therapist ratings of outcome were enhanced by pretreatment dissimilarities in value placed on social ascendance and achievement and similar value emphasis being placed on humanistic and philosophical concerns. Patient ratings of outcome were also enhanced if patient and therapist shared philosophical and humanistic concerns, but were further facilitated if values relating to social attachment and independence were ranked differently for patient and therapist. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of schemes for the attribution of multiple psychological causes.

Examined the development of 3 schemes for the attribution of psychological events to multiple causes, using a total of 108 5-, 9-, and 13-yr-olds. Ss were presented with a number of stories which described a behavior and specified the presence or absence of one possible cause for the behavior. For each story the S was asked to infer the presence or absence of another possible cause and the pattern of these inferences was used to assess schematic processing. The scheme for multiple sufficient causes implies that either of 2 facilitory causes is sufficient to produce the effect; this scheme was present in the 9- and 13-yr-olds but not in the 5-yr-olds. When 1 of 2 sufficient causes was inhibitory rather than facilitory, this scheme was complicated to the extent that it appeared only in the 13-yr-olds. The scheme for multiple necessary causes implies that both of 2 causes must be present to produce the effect; this too was present only in the 13-yr-olds. Probable relations between these schematic developments and general characteristics of Piagetian cognitive stages are outlined. Consistencies and discrepancies with previously reported findings are identified. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)