30-GHz bandwidth 1.55-/spl mu/m strain-compensated InGaAlAs-InGaAsP MQW laser

High-speed 1.55 /spl mu/m laser diodes with a 3-dB modulation bandwidths of 30 GHz were fabricated by using short-cavity mushroom structures with undoped, strain-compensated InGaAlAs-InGaAsP twenty-quantum-well active regions. The bandwidths were achieved at low bias current of 100 mA. The laser exhibited a high differential gain of 1.54/spl times/10/sup -15/ cm/sup 2/ and a small K factor of 0.135 ns. These results were achieved by using an In/sub 0.386/Ga/sub 0.465/AlAs barrier with 0.83% tensile strain to reduce the thermal emission time of holes from wells and hence the hole transport time.     

Clinical analysis of elderly patients with malignant lymphoma

An epidemiological study on 173 consecutive elderly malignant lymphoma patients age 65 years or over was performed and the clinical outcome of chemotherapy is reported. Of there, 131 patients (75.7%) had non-Hodgkin's lymphoma (NHL) and 21 patients had Hodgkin's disease (HD). As for clinical staging, 58.9% of patients were in stage 3 or 4. The initial sites were nodal in 61.8% of the patients the most common sites of involvement in superficial lymph nodes being cervical, inguinal and axillar. The most frequent site of extranodal involvement was the gastrointestinal tract. The cases were treated with CHOP/COPP, BACOP or COP-BLAM combination chemotherapy. The clinical efficacy of these modalities was similar, with complete remission rates being about 50%. However, the total response rate (CR+partial remission) by the COP-BLAM regimen were 88.1%. The median survival time of cases achieving CR, was longer than 47 months. The most frequent cause of death was infection, especially pneumonia and septicemia. Many elderly ML patients were found and diagnosed when the disease developed to an advanced stage. Therefore it is necessary to make efforts to find early ML patients by screening apparently healthy elderly people. Improvement of the complete remission rate should be obtained if vigorous and intensive chemotherapy is carried out with careful supportive therapy concerning the general condition and complications in patients.     

Current forging technology for integrated type steel forgings for nuclear steam supply system components

This brief review concerns the trend in using large size, integrated type steel forgings for nuclear steam supply system components as intended for easier in-service inspection (ISI).To achieve this trend, unique forging techniques have been developed.The forging techniques corresponding to each integrated type steel forging product together with a brief explanation of the development of forging facilities as well as a future aspects are introduced.     

New Ink Jet Recording for Generating a Plurality of Ink Jet Streams

A new solid-state scanning ink jet recording technique, called slit jet recording, is proposed. This technique uses a recording head with one slitlike ink-issuing opening having a number of recording electrodes arrayed along a horizontal scanning direction. The ink is emitted from the ink-issuing opening due to the electrical potential difference between a driven recording electrode and a counterelectrode located behind the recording paper. The ink strikes the paper and forms a recording dot. Many recording electrodes can be driven simultaneously by video signals which enhance the total copy recording speed over that for conventional techniques using a single nozzle. The head of this ink jet recording apparatus is remarkably simple in construction and can be fabricated without difficulty. Improvements in reliability and maintainability can also be expected, as the simple structure of the ink-issuing opening reduces clogging and facilitates easy cleaning as compared with other equipment having a large number of nozzles. The recording principle and characteristics and ink-issuing characteristics are described, and the results of a trial recording are presented. The results show that an ISO A4 size (210 mm x 297 mm) full-color copy can be recorded in about 30 s at an 8-dot/ mm rate.     

An experimental 1.5-V 64-Mb DRAM

Low-voltage circuit technologies for higher-density dynamic RAMs (DRAMs) and their application to an experimental 64-Mb DRAM with a 1.5-V internal operating voltage are presented. A complementary current sensing scheme is proposed to reduce data transmission delay. A speed improvement of 20 ns was achieved when utilizing a 1.5-V power supply. An accurate and speed-enhanced half-V_CC voltage generator with a current-mirror amplifier and tri-state buffer is proposed. With it, a response time reduction of about 1.5 decades was realized. A word-line driver with a charge-pump circuit was developed to achieve a high boost ratio. A ratio of about 1.8 was obtained from a power supply voltage as low as 1.0 V. A 1.28 μm² crown-shaped stacked-capacitor (CROWN) cell was also made to ensure a sufficient storage charge and to minimize data-line interference noise. An experimental 1.5 V 64 Mb DRAM was designed and fabricated with these technologies and 0.3 μm electron-beam lithography. A typical access time of 70 ns was obtained, and a further reduction of 50 ns is expected based on simulation results. Thus, a high-speed performance, comparable to that of 16-Mb DRAMs, can be achieved with a typical power dissipation of 44 mW, one tenth that of 16-Mb DRAMs. This indicates that a low-voltage battery operation is a promising target for future DRAMs     

Effects of bioabsorbable and non-resorbable barrier membranes on bone augmentation in rabbit calvaria

The aim of this study was to compare the effects of bioabsorbable and non-resorbable membranes on experimental guided bone augmentation in 8 Japanese white rabbits. A cutaneous flap was demarcated and raised from the forehead of each animal, the periosteum was lifted, and the calvarial bone on both sides of the midline was exposed. A titanium screw was inserted into the bone on each side of the midline and one screw was covered with a bioabsorbable (polylactic acid) membrane and the other with a non-resorbable (expanded polytetrafluoroethylene) membrane. The implanted screws and membranes were then covered with the periosteum and cutaneous flap. After healing for 6 months, the animals were euthanized and the experimental area was prepared for histological investigation. New bone had formed under both membranes with no sign of infection or membrane exposure. The amount of newly generated bone (89.0 +/- 17.3% versus 54.7 +/- 14.0%, P <0.05) and the percentage of newly generated bone height (81.5 +/- 6.3% versus 58.9 +/- 7.8%, P <0.05) in the space beneath the non-resorbable membrane was greater than that beneath the bioabsorbable membrane. However, there were no statistically significant differences between the bioabsorbable and non-resorbable membranes with respect to the percentage areas of mineralized bone (52.3 +/- 11.3% versus 47.1 +/- 6.7%, P = 0.8658) and bone marrow (47.7 +/- 11.3% versus 52.9 +/- 6.7%, P = 0.4838) and bone contact with the screw (88.3 +/- 6.9% versus 89.2 +/- 7.3%, P = 0.9999). In conclusion, at least within the limitations of this rabbit model, we suggest that non-resorbable membranes with sufficient stiffness should be used to obtain greater bone volume and height instead of bioabsorbable membranes for the GBR procedure, and that this will facilitate predictable bone augmentation in spaces beyond the bone surface. Therefore, the bioabsorbable membrane could not replace the non-resorbable membrane used in this model.     

Far-infrared laser oscillations from H2CO

Lasting laser oscillation was obtained from H2CO vapor with a longitudinal-flow tube. Ten lasing lines, including six new lines, have been observed in the pressure range of 0.18-0.35 torr. The optimum conditions were 2.5-7.1 kV and 2.5 Hz for excitation voltage and pulse repetition rate, respectively. The pulse shape of the lines was observed by an Ni-W diode.     

BCL-2 overexpression attenuates cortical cell loss after traumatic brain injury in transgenic mice

The proto-oncogene, BCL-2, has been suggested to participate in cell survival during development of, and after injury to, the CNS. Transgenic (TG) mice overexpressing human Bcl-2 (n = 21) and their wild-type (WT) littermates (n = 18) were subjected to lateral controlled cortical impact brain injury. Lateral controlled cortical impact brain injury resulted in the formation of a contusion in the injured cortex at 2 days, which developed into a well-defined cavity by 7 days in both WT and TG mice. At 7 days after injury, brain-injured TG mice had a significantly reduced cortical lesion (volume = 1.99 mm3) compared with that of the injured WT mice (volume = 5.1 mm3, P < 0.01). In contrast, overexpression of BCL-2 did not affect the extent of hippocampal cell death after lateral controlled cortical impact brain injury. Analysis of motor function revealed that both brain-injured WT and TG mice exhibited significant right-sided deficits at 2 and 7 days after injury (P < 0.05 compared with the uninjured controls). Although composite neuroscores (sum of scores from forelimb and hind limb flexion, lateral pulsion, and inclined plane tests) were not different between WT and TG brain-injured mice, TG mice had a slightly but significantly reduced deficit in the inclined plane test (P < 0.05 compared to the WT mice). These data suggest that the cell death regulatory gene, BCL-2, may play a protective role in the pathophysiology of traumatic brain injury.     

Impact of Al in Cu alloy interconnects on electro and stress migration reliabilities

The reliability of Cu interconnects was successfully improved by applying a CuAl alloy seed. However, the effect of additive Al on the reliability is not fully understood. In order to reveal the reliability improvement mechanism, Cu films using CuAl alloy seed were investigated in detail. As stress induced voiding (SIV) as well as electromigration is caused by migration of vacancies and/or Cu atoms, the measured activation energy value of electromigration using CuAl indicates that the fast diffusion paths are Cu grain boundaries. The analysis using high lateral resolution scanning type secondary ion mass spectrometry (nano-SIMS) clarifies that additive Al in ECP-Cu film is mainly localized at grain boundaries. Furthermore, positron annihilation was used to probe vacancy-type defects in Cu films. The CuAl films before recrystallization contain larger and higher density vacancy-type defects. Whereas, the recrystallized CuAl films after annealing above 250 °C contain smaller and lower density defects. Furthermore, CuAl films with annealing above 350 °C contain less Al inside the grains. These results represent that Al atoms in Cu films with annealing above 350 °C are exhausted from inside grains to the grain boundaries, and the spewed Al atoms existing at Cu grain boundary effectively prevents the diffusion of Cu and/or vacancies.     

The study on change of mechanical properties of NBR due to deterioration

Rubber is an important industrial material. However, mechanical properties and deformation of the high polymer including rubber are not clear. A method of estimating the mechanical properties which can be used for the deteriorated rubber is demanded to improve the reliability of it. Improved VBO (Viscoplasticity theory based on overstress) model is a constitutive equation. We applied it for the compression stress-strain behavior of deteriorated NBR (acryloNitrile-Butadiene rubber). Furthermore, we proposed a method of estimating the mechanical properties of deteriorated NBR. In this paper, deterioration tests in water and in air were conducted. To confirm the validity of the proposed improved VBO model and estimated mechanical properties, simulations of the stress-strain curves obtained in the tests were conducted.