Development of an Evolutionary Three-Dimensional Scroll Compressor

A novel three-dimensional scroll compressor was developed. The authors have produced 3D scroll compressor since 2004. The 3D scroll is able to compress refrigerant in axial direction as well as in existing radial direction by employing steps at the bottom and the tip of the scroll which change the height of compression chamber on the middle of the compression process. For the purpose of further performance improvement, the authors developed an evolutionary three-dimensional compression mechanism, named e-3D scroll . The e-3D scroll is equipped with a sloped tip and a sloped end plate in each scroll instead of the steps in the conventional 3D scroll. The height of compression chamber decreases continuously with progression of compression by the sloped shape. The e-3D scroll achieved considerable efficiency improvement compared to the conventional 3D scroll since there is no leakage loss in the steps while keeping the advantages of high compression ratio, large capacity and small size by the sloped tip and end plate. In addition, the noise and vibration of the e-3D scroll compressor reduced significantly since the rate of change of cylinder volume throughout the compression process and the torque variation in the rotation became smaller than the conventional 3D scroll. This article describes the compression mechanism and the performance improvement technology in the e-3D scroll

Spectroscopic Observation of the Interface States at the SiO₂/4H-SiC(0001) Interface

We obtained the energy distribution of the interface states at the SiO2/4H-SiC(0001) interface using operando hard x-ray photoelectron spectroscopy. Two types of interface states were observed: one with continuous interface states in the entire SiC band-gap and the other with sharp interface states formed below the conduction band minimum (CBM). The continuous interface states in the whole gap were attributed to carbon clusters while the sharp interface states observed near the CBM were due to the Si2—C=O state and/or the Si2—C=C—Si2 state at the SiO2/SiC interface

Low-Capture-Power Test Generation for Scan-Based At-Speed Testing

Scan-based at-speed testing is a key technology to guarantee timing-related test quality in the deep submicron era. However, its applicability is being severely challenged since significant yield loss may occur from circuit malfunction due to excessive IR drop caused by high power dissipation when a test response is captured. This paper addresses this critical problem with a novel low-capture-power X-filling method of assigning 0\u27s and 1\u27s to unspecified (X) bits in a test cube obtained during ATPG. This method reduces the circuit switching activity in capture mode and can be easily incorporated into any test generation flow to achieve capture power reduction without any area, timing, or fault coverage impact. Test vectors generated with this practical method greatly improve the applicability of scan-based at-speed testing by reducing the risk of test yield lossIEEE International Conference on Test, 2005, 8 November 2005, Austin, TX, US

SIRT1 negatively regulates the expression of Prl2C3,a senescence-associated protein

SIRT1 is a mammalian homologue of yeast longevity protein Sir2. SIRT1 deacetylates transcription factors, cofactors, and histones in an NAD+-dependent manner, and promotes cell survival, anti-oxidative function, and DNA repair. Although some studies have indicated that SIRT1 is involved in longevity, the function of SIRT1 for preventing aging and senescence is still unclear. In mouse embryonic fibroblasts (MEFs), we found that SIRT1 expression decreased by aging and IRT1 reciprocally regulated the expression level of Prl2C3, one of the prolactin-like peptides. In young MEFs, purified Prl2C3 inhibited the growth and increased the number of senescence-associated β galactosidase-positive cells with enlarged and flattened shapes. Moreover, immunostaining of human skin sections showed the expression of Prl2C3 in the basal cells of the epidermis. These results indicate that SIRT1 negatively regulates a senescence-associated protein rl2C3