137 research outputs found
Cardiac Arrest Due to Tension Pneumoperitoneum Caused by Esophagogastric Perforation and Pyloric Stenosis : A Case Report
Article信州医学雑誌 67(2): 113-119(2019)journal articl
Energy dissipation decrease during adiabatic charging of a capacitor by changing the duty ratio
Adiabatic charging of a capacitor with a step down converter by changing the duty ratio is considered. First, for a profound understanding of the circuit, the general analytical solution of step down converter is considered. It is confirmed that the system can be resolved analytically and that the equilibrium state of current and voltage are consistent with SPICE simulation. Next, adiabatic charging by changing the duty ratio is investigated. From SPICE simulation, it is confirmed that energy dissipation is reduced to one-fourth when four-step charging is used. By increasing the step number, energy dissipation decreases to zero and dissipationless operation is achieved. Adiabatic charging of a capacitor with a step down converter by changing the duty ratio is considered. First, for a profound understanding of the circuit, the general analytical solution of step down converter is considered. It is confirmed that the system can be resolved analytically and that the equilibrium state of current and voltage are consistent with SPICE simulation. Next, adiabatic charging by changing the duty ratio is investigated. From SPICE simulation, it is confirmed that energy dissipation is reduced to one-fourth when four-step charging is used. By increasing the step number, energy dissipation decreases to zero and dissipationless operation is achieved. © 2011 IEEE
Increasing static noise margin of single-bit-line SRAM by lowering bit-line voltage during reading
A 64-kb SRAM circuit with a single bit line (BL) for reading and with two BLs for writing was designed. Single-BL reading is achieved by using a left access transistor and a left shared reading port. We designed the cell layout and confirmed that there is no area penalty for producing two word lines in a memory cell. An analysis of butterfly plots clearly confirms that the single-BL SRAM has the larger static noise margin than the two-BL one. It is confirmed that the static noise margin in the single-BL SRAM is further increased when the BL is precharged to not VDD but to the lower value in the range of VDD/2 to 3VDD/4. In addition, a new sense amplifier circuit without reference voltage is proposed for single-BL reading. We also propose a divided word line architecture for writing to maintain the static noise margin for unwritten blocks. © 2011 IEEE
Simultaneous enlargement of SRAM read/write noise margin by controlling virtual ground lines
金沢大学理工研究域電子情報学系The SRAM operating margin in 65nm technology is analyzed. The peak characteristic in the read margin versus the supply voltage was found to be caused by the channel length modulation effect. Controlling the memory cell virtual ground line proved to be effective in enlarging the operating margin simultaneously in the read and the write operations. A simple o ptimum circuit which does not require any dynamic voltage c ontrol is proposed, realizing an improvement in the operating m argin comparable to conventional circuits requiring dynamic voltage control. © 2010 IEEE
Accelerated evaluation method for the SRAM cell write margin using word line voltage shift
An accelerated evaluation method for the SRAM cell write margin is proposed based on the conventional Write Noise Margin (WNM) definition. The WNM is measured under a lower word line voltage than the power supply voltage VDD. A lower word line voltage is used because the access transistor operates in the saturation mode over a wide range of threshold voltage variation. The final WNM at the VDD word line voltage, the Accelerated Write Noise Margin (AWNM), is obtained by shifting the measured WNM at the lower word line voltage. The amount of WNM shift is determined from the WNM dependence on the word line voltage. As a result, the cumulative frequency of the AWNM displays a normal distribution. A normal distribution of the AWNM drastically improves development efficiency, because the write failure probability can be estimated by a small number of samples. Effectiveness of the proposed method is verified using the Monte Carlo simulation. © 2011 IEEE
Search for Outer Massive Bodies around Transiting Planetary Systems: Candidates of Faint Stellar Companions around HAT-P-7
We present results of direct imaging observations for HAT-P-7 taken with the
Subaru HiCIAO and the Calar Alto AstraLux. Since the close-in transiting planet
HAT-P-7b was reported to have a highly tilted orbit, massive bodies such as
giant planets, brown dwarfs, or a binary star are expected to exist in the
outer region of this system. We show that there are indeed two candidates for
distant faint stellar companions around HAT-P-7. We discuss possible roles
played by such companions on the orbital evolution of HAT-P-7b. We conclude
that as there is a third body in the system as reported by Winn et al. (2009,
ApJL, 763, L99), the Kozai migration is less likely while planet-planet
scattering is possible.Comment: 8 pages, 3 figures, 2 tables, PASJ in pres
A Substellar Companion to Pleiades HII 3441
We find a new substellar companion to the Pleiades member star, Pleiades HII
3441, using the Subaru telescope with adaptive optics. The discovery is made as
part of the high-contrast imaging survey to search for planetary-mass and
substellar companions in the Pleiades and young moving groups. The companion
has a projected separation of 0".49 +/- 0".02 (66 +/- 2 AU) and a mass of 68
+/- 5 M_J based on three observations in the J-, H-, and K_S-band. The spectral
type is estimated to be M7 (~2700 K), and thus no methane absorption is
detected in the H band. Our Pleiades observations result in the detection of
two substellar companions including one previously reported among 20 observed
Pleiades stars, and indicate that the fraction of substellar companions in the
Pleiades is about 10.0 +26.1/-8.8 %. This is consistent with multiplicity
studies of both the Pleiades stars and other open clusters.Comment: Main text (14 pages, 4 figures, 4 tables), and Supplementary data (8
pages, 3 tables). Accepted for Publications of Astronomical Society of Japa
Extreme Asymmetry in the Disk of V1247 Ori
We present the first near-infrared scattered-light detection of the
transitional disk around V1247 Ori, which was obtained using high-resolution
polarimetric differential imaging observations with Subaru/HiCIAO. Our imaging
in the H band reveals the disk morphology at separations of ~0.14"-0.86"
(54-330 au) from the central star. The polarized intensity (PI) image shows a
remarkable arc-like structure toward the southeast of the star, whereas the
fainter northwest region does not exhibit any notable features. The shape of
the arm is consistent with an arc of 0.28" 0.09" in radius (108 au from
the star), although the possibility of a spiral arm with a small pitch angle
cannot be excluded. V1247 Ori features an exceptionally large azimuthal
contrast in scattered, polarized light; the radial peak of the southeastern arc
is about three times brighter than the northwestern disk measured at the same
distance from the star. Combined with the previous indication of an
inhomogeneous density distribution in the gap at 46 au, the notable
asymmetry in the outer disk suggests the presence of unseen companions and/or
planet-forming processes ongoing in the arc.Comment: 21 pages, 5 figures, accepted for publication in PAS
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