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We developed 3.3 kV-class silicon carbide superjunction (SJ) MOSFETs and demonstrated their excellent static and dynamic properties. The full-SJ device exhibited ultra-low R on A of 3.3 mΩcm2 at room temperature (RT) and 6.2 mΩcm2 at 175 °C. The small reverse recovery charge of SJ devices at RT and 175 °C was realized by injection level suppression. Owing to these advantages, superior total power loss was estimated when the SJ-devices were operated as a half-bridge synchronous rectifier. more...

This study demonstrated the short-circuit performance of 1.2 kV-class silicon carbide (SiC) trench-gate superjunction MOSFET (SJ-UMOSFET) through experiments and numerical simulation. The SJ structure showed a substantially improved trade-off between specific on-resistance and short-circuit capability when compared with a conventional UMOSFET, especially at a high temperature (175°C), owing to the low temperature coefficient of the specific on-resistance. Furthermore, the electro-thermal simulation showed that the SJ-UMOSFET exhibited a larger distance from an internal hot spot to the source metal contact than the UMOSFET; this increase in distance contributed to the improved short-circuit capability demonstrated in the experiment. more...

SiC SJ MOSFETs had exhibited soft recovery characteristics at room temperature in comparison with that of non-SJ MOSFETs. In this study, the static and dynamic characteristics of the SiC SJ MOSFET at high temperature have been first demonstrated to clarify the mechanism of the soft recovery of the body-diode. The $\boldsymbol{R_{onA}}$ at high temperature was drastically decreased by the SJ structure due to small drift resistance with suppressed injection level. The hard recovery characteristics are suppressed by the low injection level and large output capacitance ( $\boldsymbol{C_{oss}}$ ) compared with those in the Si SJ MOSFETs, indicating the great potential of SiC SJ MOSFET in various applications. more...

A 1.2 kV-class superjunction (SJ) UMOSFET was realized using a multi-epitaxial growth method. The dynamic characteristics were characterized, and the potential of a product level device was identified for the first time. The switching characteristics with Schottky barrier diode showed no degradation in spite of the large drain-source capacitance (C DS ). The reverse recovery characteristics of the body diode exhibited a soft recovery which may originate from the large C DS and the short lifetime of minority carrier. A high short circuit capability comparable to a non-SJ device was demonstrated. more...

Integration of SBD into SiC-MOSFET is promising to solve body-PiN-diode related problems known such as forward degradation and reverse recovery loss. Particularly in lower breakdown-voltage-class SBD-integrated MOSFET, cell pitch reduction has a greater impact on inactivating the body-PiN-diode. Here, we developed a novel device called an SBD-wall-integrated trench MOSFET (SWITCH-MOS), in which small cell pitch of 5p.m was realized by utilizing trench side walls both for SBD and MOS channel with buried p+ layer. The fabricated 1.2 kV SWITCH-MOS successfully suppressed the forward degradation under extremely high current density condition with low switching loss, low specific on-resistance, and low leakage current. more...

To understand the mechanisms linking platelets to the risk of coronary artery disease, we investigated the relation between coronary angiographic morphology and platelet indexes – platelet count, mean platelet volume (MPV), platelet-large cell ratio (P-LCR) and platelet distribution width (PDW) – in patients with ischemic heart disease. Eighty-four patients with ischemic heart disease and 120 aged controls (AC) were enrolled in the study. The patients without any signs of acute myocardial infarction and acute coronary syndromes who underwent coronary angiography were divided into two groups, an ‘angiographically negative group’ (group 0) and an ‘angiographically positive group’ (group 1), with positive coronary obstruction depending on the diagnostic criteria in our hospital. Platelet indexes were measured in peripheral venous blood. The mean platelet counts were significantly lower in groups 1 and 0 than in AC (p = 0.0128 and p = 0.0041, respectively). MPV, P-LCR and the PDW were significantly higher in group 0 than in group 1 and AC (p = 0.0352 and 0.0433, p = 0.0059 and 0.0052, p = 0.00461 and 0.0146, respectively). The indexes of group 1 were almost the same compared with AC with respect to MPV, P-LCR and PDW. In conclusion, these findings suggest that the measurement of platelet indexes may reflect the underlying pathophysiological state and subsequent clinical events in the patients. In particular, lower P-LCR seems to identify patients with positive coronary angiography. more...

A three-dimensional (3-D) vertical chain-cell-type phase-change memory (VCCPCM) for next-generation large-capacity storage was developed. The VCCPCM features formation of memory holes in multi-layered stacked gates by using a single mask and a memory array without a selection transistor. As a result of this configuration, the number of process steps for fabricating the VCCPCM is reduced. The excellent scalability of the VCCPCM's new phase-change material makes it possible to reduce the cell size beyond the scaling limit of flash memory. In addition, a poly-silicon selection diode makes it possible to reduce the cell factor to 4F2. Consequently, relative cost of the VCCPCM compared to 3-D flash memory is reduced to 0.2. more...

A double blind study was conducted to objectively evaluate the usefulness of Cefuzonam (CZON) in the treatment of bacterial pneumonia and lung abscess. Cefotiam (CTM) was used as a control drug. Each drug was administered by intravenous drip infusion at 1 g at a time, twice daily, for 14 days as a rule. The results are as follows: 1. Enrolled in this study were 145 cases in total, comprising 72 of CZON group and 73 of CTM group. Of the total cases, 109 (53 of CZON group and 56 CTM group) were evaluated for clinical efficacy by the evaluation committee. Exclusion rate and background of patients were not significantly different between the two groups. 2. Clinical effectiveness assessed by the committee showed the efficacy rates of 84.9% (45 cases out of 53) for the CZON group and 83.3% (47 cases out of 56) for the CTM group, with no significant difference between the two groups. 3. The bacteriological eradication rates were 89.5% (17 strains out of 19) for the CZON group and 78.3% (18 strains out of 23) for the CTM group, with no significant difference between the two groups. 4. The incidence of side effects was 5 cases (7.5%) for the CZON group and 3 cases (4.2%) for the CTM group. The incidence rate of laboratory test abnormality was 28.4% (19 cases out of 67) for the CZON group and 31.3% (12 cases out of 67) for the CTM group. There was no significant difference between the two groups. 5. Usefulness rates calculated by the committee were 79.2% (42 cases out of 53) for the CZON group and 76.8% (43 cases out of 56) for the CTM group. There was no significant difference between the two groups. These results show that CZON is a useful drug in the treatment of bacterial pneumonia and lung abscess. more...

To understand the heterogeneity of platelets, we investigated the correlation between hemostatic factors and the platelet index [platelet count, mean platelet volume (MPV), platelet-large cell ratio (P-LCR) and platelet distribution width (PDW)] in patients with ischemic heart disease (IHD). Ninety-seven patients with IHD and 120 aged controls (AC) were enrolled in the study. D-dimer, thrombin-antithrombin III complex (TAT), von Willebrand factor antigen (VWF:Ag) and platelet indexes were measured in the peripheral venous blood. The D-dimer and TAT levels in the patients were significantly elevated compared to the AC. VWF:Ag was also elevated, but not significantly so. However, no differences were observed in the platelet index between the patients and the AC. In the patients, the level of VWF:Ag was significantly inversely correlated with the platelet count, but such correlations were not observed in the D-dimer and TAT. TAT was significantly positively correlated with MPV, P-LCR and PDW. VWF:Ag was also correlated, though not significantly, with MPV, P-LCR and PDW. The D-dimer was not correlated with the platelet index. In the AC, the platelet count was inversely correlated with VWF:Ag, but not significantly so. VWF:Ag showed significant positive correlations with MPV, P-LCR and PDW. However, the D-dimer and TAT were not correlated with the platelet index in AC. These findings suggest that VWF:Ag and TAT seem to be profoundly related to platelet volume. more...

✓ A patient with subarachnoid hemorrhage was found to have electrocardiographic abnormalities resembling an acute myocardial infarction as well as left ventriculographic findings of cardiac dysfunction. These cardiac abnormalities resolved following surgical clipping of the aneurysm and the patient recovered well from the operation. She died 2 months later from cancer and a postmortem examination at that time revealed no evidence of myocardial necrosis. In this report, the authors discuss coronary vasospasm and reversible postischemic “stunned myocardium,” a condition that has not been considered previously in relation to subarachnoid hemorrhage. more...

We report a case of sporadic amyotrophic lateral sclerosis (ALS) characterized by a marked accumulation of neurofilaments in the cytoplasm of neurons. The neurofilament was identified by immunohistochemical and electron microscopic studies. The distribution of the accumulation in this case was unique, not only in the motoneurons of the anterior horn but also in the neurons of the other areas of the spinal gray matter, some nuclei in the brain stem, pontine reticular formation, substantia nigra, dentate nucleus in the cerebellum and pyramidal cells in the motor cortex. These observations shed light on the pathogenesis of ALS. more...

The plasma levels of von Willebrand factor (vWF), protein C (PC) and antithrombin III (AT III) were examined in 32 patiens with cerebrovascular disease (CVD).The mean vWF activity in 17 patients with cerebral infarction of acute phase was significantly higher (p more...

The plasma levels of von Willebrand factor (vWF), factor VIII procoagulant activity (factor VIII) and protin C (PC), were followed in 39 patients with myocardial infarction (MI).The mean vWF activity in the acute stage of MI was significantly higher (p more...