Standardization Committee for Haematology. External Quality Assurance Program for General Hematology. Evaluation of the 1994 results

Concerns about the cultural competence of child mental health services has led to the examination of racial/ethnic and gender differences in the prevalence of psychiatric symptoms. This study examines racial and gender differences in depressive and substance abuse symptomatology in a high-risk population of adolescents living in five residential group homes in South Carolina. We surveyed 299 youth ages 12 to 17, including 101 African American and 198 Whites. They completed the Centers for Epidemiological Studies-Depression scale (CES-D) and questions on substance abuse, demographics, and psychosocial functioning. No significant differences were found in the percentages of Whites and African Americans scoring above 16+ and 23+ cutoff scores on the CES-D, but significant gender differences were identified. Neither race nor race by age group interactions were found to be significantly correlated in regression analyses with CES-D score nor multiple substance use, whereas gender (p < .001) and school performance were significantly correlated with CES-D score, and poverty was correlated with multiple substance use. Our results indicate that levels of depressive symptomatology as measured by the CES-D are much more sensitive to gender than to race in high-risk populations. Different gender cutoffs are indicated when using systematic instruments in the measurement of depressive symptoms.     

Active Frequency-Tune Beam-Scanning Leaky-Wave Antenna Arrays

X-band active beam-scanning leaky-wave antenna arrays, including 1 × 1,1 × 2 and 1 × 4 prototypes, have been demonstrated. These antennas integrated one or several microstrip leaky-wave antenna elements with a single varactor-tuned HEMT VCO as an active source. Measured results on experimental antennas indicate that the beam scanning angle of the 1 × 1 antenna close to 40° can be achieved and the scanning range of 1 × 2 and 1 × 4 antenna arrays are both close to 32°. Furthermore, reflected wave due to the open end of each leaky-wave antenna element has been suppressed by the symmetric configuration of this antenna array and the antenna efficiency increases. When comparing with the measured radiation pattern of the single element antenna, we found that the 1 × 2 and 1 × 4 antenna arrays can effectively suppress the reflected power by more than 5.5 dB and 10.5 dB, respectively, at 10.2GHz. The power gain are more than 2 dB and 3.16 dB higher than the single element antenna with a measured EIRP of 18.67 dBm.     

Effect of chlorination bulking control on water quality and phosphate release/uptake in an anaerobic-oxic activated sludge system.

This study evaluates the effect of chlorination bulking control on water quality and phosphate release/uptake in an anaerobic-oxic activated sludge system. A series of batch experiments with different specific NaOCl mass dose were conducted to determine the sludge settling properties, supernatant water quality and phosphate metabolism behavior of filamentous bulking sludge. The harvested sludge was from a continuous-flow anaerobic-oxic (A/O) activated sludge pilot-plant, i.e., enhanced biological phosphorus removal (EBPR) system, operated with 15 days of sludge retention time. The filamentous bacteria in the A/O pilot plant were identified to be Thiothrix according to Eikelboom's classification techniques, which was in accordance with the high influent sulfate concentration of this study (50 mg/L sulfate). Increasing NaOCI concentration, as revealed by experimental results, obviously decreased the sludge settling properties (SVI values and zone settling velocities) and meanwhile significantly reduced supernatant water quality (COD, SS, TP) mainly due to higher suspended solids caused by floc disruption. Moreover, the nine-hour batch experiments indicated that high NaOCI dosage (40 mg/gMLSS) completely deteriorated phosphate metabolism of EBPR sludge. Such a high dosage of chlorination further confirmed overdosing through disappearance of intracellular PHB and death of protozoa by microscopic investigation. Still, phosphate release/uptake behavior of EBPR sludge properly functions at low NaOCl dosage (5 mg/g MLSS). Besides, phosphate metabolism worsens rapidly before the SVI value reaches its lowest level. These findings imply that determining NaOCI requirement with merely SVI values can readily result in chlorination overdosing. Proper NaOCI dosage requires a delicately balanced consideration between sludge settling improvement, water quality demand and phosphate metabolism. Batch test of phosphate release/uptake is apparently a prerequisite to conclude an appropriate NaOCl dosage for bulking control.     

A physical model for the correlation between holding voltage andholding current in epitaxial CMOS latch-up

A new physical model concerning the holding points for latch-up in epitaxial CMOS structures is established by combining the lateral p-i-n high level injection and the vertical BJT base push-out formula. The model matches adequately the correlation between holding voltage and holding current extensively measured from different combinations of temperatures, epitaxial layer thicknesses, and anode-to-cathode spacings. This is also the case for the two-dimensional device simulations. A quantitative analysis based on the model consistently judges the crucial role of the vertical BJT base push-out width in producing the observed correlation. The potential merits of the model in extended applications are outlined     

Thermal,mechanical and chemical effects in the degradation of the plasma-deposited α-SiC:H passivation layer in a multilayer thin-film device

Amorphous, hydrogenated silicon carbide (-SiC:H) deposited by a plasma-enhanced-chemical-vapour-deposition (PECVD) process has been used as the topmost passivation layer in a multilayer thin-film device, namely, a thermal ink-jet printhead. Normal operations of the device involve rapid heating of the multilayer structure at several kHz, repetitively forming vapour bubbles that grow and collapse in an otherwise liquid environment. During such operations, the -SiC:H layer is subjected to a variety of thermal, mechanical and chemical stresses that are detrimental to its integrity. It is found that thermally activated failures may occur when the multilayer structure is driven for extended periods of time or by pulses of excessive magnitude or duration, or when the -SiC:H film is so thick as to store excessive elastic energy due to large differential thermal expansion effects. It is also found that severe mechanical (namely, cavitation) effects associated with bubble collapse cause early device failures if the surface of the device is exposed to an unlimited liquid reservoir; however, such adverse effects are greatly mitigated by the presence of a nozzle plate in the vicinity of the top surface. Finally, it is shown that high pH and various chemicals tend to etch the -SiC:H thin film through an oxidation-dissolution process, removing the passivating material rapidly and leading to device failures.     

General formula for bending beam determination of case II diffusion in polymer-containing bilayer structures

An exact formula has been presented to correlate the bending curvature cariation ratio, Ω, of any given bilayer structure comprising a solvent-swellable polymer layer with diffusion time, t, under case II diffusion. The formula can be used to determine the diffusion front velocity, v, for layered structures comprising a thick polymer film on a thin substrate or vice versa when subjected to solvent diffusion. According to this formula, there is little effect from plasticization or swelling in the transverse direction on the diffusion curve of Ω vs. t if the polymer layer to be investigated is relatively thin and its intrinsic hygroscopic strain ratio is less than unity. By using this model, the diffusion of N-methyl pyrollidinone (NMP) in a 18-μm rodlike pyromellitic dianhydride p-phenylene-diamine (PMDA-PDA) polymide film, coated on a 75-μm silicon substrate, is found to be case II with a diffusion front velocity of 1.84 × 10^-7 cm/s. © 1995 John Wiley & Sons, Inc.     

Branched diphenylsilane derivatives containing electronically isolated indolyl moieties as host materials for blue organic light emitting diodes

Branched diphenylsilane derivatives with pendent indolyl fragments were synthesized and characterized. The compounds show high thermal stability with thermal decomposition starting at temperatures above 367 °C and ability to form glasses with glass-transition temperatures of 53-58 °C. The electron photoemission spectra of the layers of the synthesized compounds showed ionization potentials of ca. 5.85 eV. The derivatives were tested as host materials in phosphorescent OLEDs with iridium(III)[bis(4,6-difluorophenyl)-pyridinato-N,C2′]picolinate as the guest. The device with the host derivative containing four electronically isolated indolyl fragments exhibited the best overall performance with maximum current efficiency of about 12 cd/A.     

An automatic controller extractor for HDL descriptions at the RTL

Extracting controlling finite-state machines can significantly reduce state space and thereby speed functional verification. The controller extraction algorithm uses an approach that frees it from restrictions on HDL code writing style     

Design and analysis of digital data recovery circuits using oversampling

A performance evaluation and circuit architecture for all-digital data recovery using an oversampling method is proposed. The architecture is very regular and hence very suitable for standard-cell implementation flow. Due to its feedforward architecture, the required bit-rate can be achieved through proper pipelining. These properties make the proposed architecture very suitable as soft silicon intellectual property. Analysis of BER due to the combined effects of the key design parameters like data jitter, clock jitter and oversampling ratio in the oversampling technique are carried out. Thus different specifications of data recovery can be designed with different design parameters. A module generator that can estimate the design parameters automatically is established. Design implementation shows the proposed all-digital data recovery circuit can achieve 3.07 Gbit/s (post-layout) with 0.25 mum 2.5 V CMOS technology standard-cell design and occupies 380times390 mum² chip area