Void formation mechanism in VLSI aluminum metallization

Void formation is aluminum lines caused by high-temperature heat treatment has been investigated, particularly from the aspect of mechanical interaction between the passivation layer and aluminum lines. It is found that there are two effects causing voids in aluminum lines: the deformation of the passivation layer and the so-called thermal expansion mismatch between aluminum lines and their surrounding layers. While the thermal expansion effect is independent of aluminum line dimensions, the passivation deformation effect dominates preferentially in wide aluminum lines. Bulge deformation of the passivation layer is caused by its own compressive stress, forcing the encapsulated aluminum to expand. In fine lines, void formation is controlled by the volume difference caused by the thermal expansion mismatch and aluminum diffusion     

Au-Fe-Ni permanent magnet alloys

A gold permanent magnet for an ornamental material is developed in the Au-Fe-Ni system. It is found that the magnetic properties of the An-12.5 wt% Fe-12.5 wt% Ni alloy aged at 450°C for seven hours and cold-swaged by 92 percent are Br = 0.53 T (5300 G), iHc = 40.8 kA/m (510 Oe), and (BH)max = 9.1 kJ/m³(1.1 MGOe). The Au-12.5 wt% Fe-10 wt% Ni-2.5 wt% Co alloy aged at 450°C for 2.5 h and swaged by 86 percent attained Br = 0.54 T (5400 G), iHc = 42.4 kA/m (530 Oe), and (BH)max = 9.6 kJ/m3(1.2 MGOe). In these alloys, the magnetic hardening is due to the fine Fe-Ni rich ferromagnetic particles precipitated in the Au matrix.     

Temperature dependence of the effective permeability of heat treated Sendust alloys

The temperature dependence (-10°C-70°C) of the effective permeability (μeff) of Sendust alloys (Fe-9-10 wt% Si-5-7 wt% Al) quenched at a room temperature from the various temperatures (400°C-700°C) was investigated at every 2°C in the temperature range of -10°C to 70°C. Most of the studied alloys gave a peak of μeffin the studied temperature range. The peak temperature (Tp) giving the peak μeffvaried with different alloy composition. The alloys of Tp = 20°C are supposed to correspond to the alloys of the zero magnetocrystalline anisotropy constant (K1= 0) at 20°C. The deduced K1= 0 lines at various temperatures (-10°C-50°C) were obtained for an Fe-Si-Al ternary system. The values of peak μeffat the same Tp were different, depending on alloy composition, This difference is due to the difference in the polycrystalline magnetostriction constant (λ s) of the alloys. The peak temperatures of the studied alloys vary with the different heat treatments. This variation is due to the variation of K1, induced by the change in microstructures of the alloys. The variation of the values of peak μeffwith heat treatments was small compared to the difference of those in the alloys of different composition. It seems that the variation of the λ s with heat treatments would be small. Both the compositional dependence of μeffat 20°C and the temperature sensitivity (Δμeff/ΔT) were obtained for both the alloys cooled continuously to room temperature and those quenched at room temperature from 400°C.     

Cloning and some properties of Japanese pear (Pyrus pyrifolia) polyphenol oxidase,and changes in browning potential during fruit maturation

A PCR‐amplified genomic DNA fragment encoding Japanese pear (Pyrus pyrifolia) polyphenol oxidase (PPO) was cloned and sequenced. The DNA appears to encode a 66 kDa precursor protein consisting of a 56 kDa mature protein and a 9.5 kDa N‐terminal transit peptide. The amino acid sequence showed high homology with apple PPO. The PPO mainly existed as a soluble fraction in cells and was limitedly proteolysed, while the mature form (56 kDa) was detected in plastids. Immature fruits showing high browning potential had high PPO activity and a high level of phenolics, while mature fruits showing little browning had high PPO activity but a low level of phenolics. Copyright © 2003 Society of Chemical Industry     

Power reduction techniques for a 1-Mb ECL-CMOS SRAM with an accesstime of 550 ps and an operating frequency of 900 MHz

This paper describes power reduction circuit techniques in an ultra-high-speed emitter-coupled logic (ECL)-CMOS SRAM. Introduction of a 0.25-μm MOS transistor allows a Y decoder and a bit-line driver to be composed of CMOS circuits, resulting in a power reduction of 34%. Moreover, a variable-impedance load has been proposed to reduce cycle time. A 1-Mb ECL-CMOS SRAM was developed by using these circuit techniques and 0.2-μm BiCMOS technology. The fabricated SRAM has an ultrafast access time of 550 ps and a high operating frequency of 900 MHz with a power dissipation of 43 W     

Superstructure-based design and operation for biomass utilization networks

This paper is providing a design and evaluation methodology for biomass utilization networks (B-NETs) planning in local areas. The methodology is an effort to integrate various exertions of many researchers as well as stakeholders in the biomass field including process technologies, local area classification and renewable energy mechanisms to design and evaluate B-NETs. The proposed design methodology has three steps: classification, problem formulation and suggesting solution methods. The core part of planning the B-NETs utilization methodology is the superstructure that is a super class model for the processes of biomass utilization networks that has to be built for the local area. The biomass utilization superstructure (BUSS) relates the biomass resources to their products, available processes, and possible future processes of utilization in static manner. Although the local area BUSS is static in nature, it shows the decision makers what kinds of B-NETs are, or can be, available in their area. It is important to note that for each super class process there exists a number of elemental technologies, or what we call unit process (UP), that can perform the job under the same condition with different processing constraint. To support the design and operation process a technological information infrastructure (TII) needs to be built to work as an information pool and simulation tool. With the support of TII and the BUSS different scenarios can be synthesized, analyzed and compared. Scenarios development enables the designer to check processing alternatives as well as biomass promotion mechanisms that fit the concerns of various stakeholders. The results of the methodology application can be given in the form of suggestions of a specific network class(es) or scenarios that can be applied in a class of localities with the same characteristics. Following to methodology configuration, a proposal for optimization methods is discussed and a case study for comparing biomass network scenarios in mountainous city is introduced.     

Optimal conditions to induce rat adrenal medullary changes, such as pheochromocytoma, by nicotine

AIMS: Dihydrocodeine is metabolized to dihydromorphine via the isoenzyme cytochrome P450 2D6, whose activity is determined by genetic polymorphism. The importance of the dihydromorphine metabolites for analgesia in poor metabolizers is unclear. The aim of this study was to assess the importance of the dihydromorphine metabolites of dihydrocodeine in analgesia by investigating the effects of dihydrocodeine on somatic and visceral pain thresholds in extensive and quinidine-induced poor metabolizers. METHODS: Eleven healthy subjects participated in a double-blind, randomized, placebo-controlled, four-way cross-over study comparing the effects of single doses of placebo and slow-release dihydrocodeine 60 mg with and without premedication with quinidine sulphate 50 mg on electrical, heat and rectal distension pain tolerance thresholds. Plasma concentrations and urinary excretion of dihydrocodeine and dihydromorphine were measured. RESULTS: In quinidine-induced poor metabolizers the plasma concentrations of dihydromorphine were reduced between 3 and 4 fold from 1.5 h to 13.5 h after dosing (P < 0.005) and urinary excretion of dihydromorphine in the first 12 h was decreased from 0.91% to 0.28% of the dihydrocodeine dose (P < 0.001). Dihydrocodeine significantly raised the heat pain tolerance thresholds (at 3.3 h and 5 h postdosing, P < 0.05) and the rectal distension defaecatory urge (at 3.3 h and 10 h postdosing, P < 0.02) and pain tolerance thresholds (at 3.3 h and 5 h postdosing, P < 0.05) compared with placebo. Premedication with quinidine did not change the effects of dihydrocodeine on pain thresholds, but decreased the effect of dihydrocodeine on defaecatory urge thresholds (at 1.5 h, 3.3 h and 10 h postdosing, P < 0.05). CONCLUSIONS: In quinidine-induced poor metabolizers significant reduction in dihydromorphine metabolite production did not result in diminished analgesic effects of a single dose of dihydrocodeine. The metabolism of dihydrocodeine to dihydromorphine may therefore not be of clinical importance for analgesia. This conclusion must however, be confirmed with repeated dosing in patients with pain.