New Measurement Base De-embedded CPU Load Model for Power Delivery Network Design

Motochika Okano,Koji Watanabe,Masamichi Naitoh,Ichiro Omura 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

CPU load model including on-chip wiring and package interconnection has been required for printed circuit board (PCB) design of digital products according to the improvement in the speed of CPU operation in recent years. Especially, accurate power delivery network (PDN) information inside CPU is indispensable for PCB design according to requirement of low-impedance and the broadband (from DC to GHz) from the inside of CPU to DC-DC converter. While the detailed impedance information inside CPUs is not disclosed to PCB board designers with the complicated back-end and front-end production design for CPU chip and package. This paper aims to establish new methodology to extract CPU load model with combination of measurement and simulation. The method is simple yet powerful for high-end CPU board design.

Dc SQUIDs Made of Intrinsic Josephson Junctions

Shingo Okano,Akinobu Irie,Gin-ichiro Oya 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.5I

We have fabricated and studied a dc superconducting quantum interference device (dc SQUID) based on intrinsic Josephson junctions in Bi2Sr2CaCu2Oy single crystals. The dc SQUIDs with in-plane loop geometry and two stacks of intrinsic Josephson junctions (IJJs) were successfully fabricated using a double-side etching process. Such a layout allowed us to define the SQUID inductance and the number of junctions in the stack independently. At 4.2 K, the SQUIDs showed hysteretic current-voltage characteristics with typical multiple resistive branches. When the operating temperature was elevated in order to reduce the hysteresis, clear periodic and symmetric flux-voltage characteristics due to the quantum interference between the weakest junctions in the stacks were observed. Both the number of junctions and the asymmetry in the critical currents are discussed as important factors in the operation of IJJ-SQUID.

Determinants of Postoperative Spinal Height Change among Adult Spinal Deformity Patients with Long Construct Circumferential Fusion

Rentenberger Colleen,Okano Ichiro,Salzmann Stephan N.,Shirahata Toshiyuki,Reisener Marie-Jacqueline,Shue Jennifer,Sama Andrew A.,Cammisa Frank P.,Girardi Federico P.,Hughes Alexander P. 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.2

Study Design: Retrospective clinical study. Purpose: To describe postoperative height changes and identify the predictive factors of spinal height (SH) changes among patients with adult spinal deformity (ASD) who underwent circumferential lumbar fusion with instrumentation. Overview of Literature: Postoperative height changes remain an important issue after spinal fusion surgery that affects the overall satisfaction with surgery. Previous studies of postoperative height change have focused exclusively on young patients with adolescent idiopathic scoliosis (AIS). Methods: We retrospectively reviewed the clinical and imaging data of ASD patients who underwent lumbar corrective circumferential fusion of ≥3 levels (n=106). SH was defined as the vertical distance between C2 and S1 on a standing lateral image. As potential predictors of postoperative height change, the number of lateral lumbar interbody fusion (LLIF) levels, change in spino-pelvic parameters, total number of levels fused, and pedicle subtraction osteotomies (PSO) were documented. Univariate and multivariate linear regression analyses were performed to identify the predictors of postoperative height change. Results: The mean SH change was −2.39±50.8 mm (range, −160 to 172 mm). The univariate analyses showed that the number of LLIF levels (coefficient=10.9, p =0.03), the absolute coronal vertical axis change (coefficient=0.6, p =0.01), and the absolute Cobb angle change (coefficient=−0.9, p =0.03) were significant predictors for height change. Patients with PSOs (n=14) tended to have a shorter height postoperatively (coefficient=−26.1); however, this difference was not significant (p =0.07). Multivariate analyses conducted with variables of p <0.20 showed that pelvic tilt (PT) change is an independent contributor to SH change (coefficient=−0.99, p =0.04, R2 =0.11). Conclusions: Utilizing a modified definition of SH used in previous AIS studies, we demonstrated that patients with ASD lose SH postoperatively and that PT change was an independent contributor of SH change.

Cementless Bipolar Hemiarthroplasty for Low-energy Intracapsular Proximal Femoral Fracture in Elderly East-Asian Patients: A Longitudinal 10-year Follow-up Study

Masanori Nishi,Ichiro Okano,Takatoshi Sawada,Natsuki Midorikawa,Katsunori Inagaki 대한고관절학회 2019 Hip and Pelvis Vol.31 No.4

Purpose: Short-term outcomes following cemented and cementless hemiarthroplasties (HAs) are reported to be comparable, however, long-term outcomes of cementless HA–especially among Asian patients–is limited. We aimed to assess long-term outcomes in elderly East-Asian patients with intracapsular proximal femoral fractures treated with cementless HA. Materials and Methods: We enrolled 135 patients treated with cementless HA who met our inclusion criteria. We documented bone/implant-related complications (e.g., incidences of revision hip surgery, femoral stem subsidence, dislocation, intraoperative and postoperative periprosthetic fractures, contralateral hip fractures). We included those patients who are still alive 10 years after the index surgery in the final functional analysis of the existence of pain, ambulatory status, and residential status. Results: The mean age at injury was 78.3 years (range: 60-85 years). At the 10-year follow-up, 26 of the original patients (19.3%) had survived. During follow-up, revision hip surgery was conducted in two patients (1.5%). We recorded the incidence of intraoperative fractures, postoperative periprosthetic fractures, and contralateral fractures in two (1.5%), eight (5.9%), and six patients (4.4%), respectively. Among the 10-year survivors, six patients (23.1% of the survivors) complained of groin pain, but generally reported the pain to be tolerable. Conclusion: Among elderly East-Asian patients, the incidence of revision surgery after cementless HA may be lower than that in their European counterparts, whereas the incidence of periprosthetic fractures can still be considerably higher. For patients undergoing cementless HA, prevention of such secondary fractures is of critical importance.

Mechanical properties of ABS resin reinforced with recycled CFRP

Ogi, Keiji,Nishikawa, Takashi,Okano, Yasutaka,Taketa, Ichiro The Korean Society for Composite Materials 2007 Advanced composite materials Vol.16 No.2

This paper presents the mechanical properties of a composite consisting of acrylonitrile-butadiene-styrene (ABS) resin mixed with carbon fiber reinforced plastics (CFRP) pieces (CFRP/ABS). CFRP pieces made by crushing CFRP wastes were utilized in this material. Nine kinds of CFRP/ABS compounds with different weight fraction and size of CFRP pieces were prepared. Firstly, tensile and flexural tests were performed for the specimens with various CFRP content. Next, fracture surfaces of the specimens were microscopically observed to investigate fracture behavior and fiber/resin interface. Finally, the tensile modulus and strength were discussed based on the macromechanical model. It is found that the elastic modulus increases linearly with increasing CFRP content while the strength changes nonlinearly. Microscopic observation revealed that most carbon fibers are separated individually and dispersed homogeneously in ABS resin. Epoxy resin particles originally from CFRP are dispersed in ABS resin and seem to be in good contact with surrounding resin. The modulus and strength can be expressed using a macromechanical model taking account of fiber orientation, length and interfacial bonding in short fiber composites.

Electrical properties of ABS resin reinforced with recycled CFRP

Nishikawa, Takashi,Ogi, Keiji,Tanaka, Toshiro,Okano, Yasutaka,Taketa, Ichiro The Korean Society for Composite Materials 2007 Advanced composite materials Vol.16 No.1

Composite materials consisting of crushed carbon fiber reinforced plastics (CFRP) pieces and acrylonitrile-butadiene-styrene (ABS) resin were prepared by an injection mold method to solve the problem of recycling of CFRP. The electrical properties, such as electrical resistivity, alternating current impedance and electromagnetic interference (EMI) shielding effect, were measured for the composites. The electrical resistivity of the composites showed a percolation type of conduction behavior and no difference between parallel and perpendicular to the injection direction was observed for CFRP content higher than the critical value. Measurement of alternating current impedance revealed that the conduction mechanism is attributed to the direct conductive paths generated by distributed carbon fibers; however, strong frequency dependence of the impedance was observed for the CFRP content near the critical one. The frequency dependence of the impedance is caused by the inter-fiber connection and can be expressed as a simple equivalent circuit. The absorption component of shielding effect (SE) was smaller than the expected value estimated from its resistivity. The decline of SE is thought to be caused by the decrease in effective thickness due to fiber orientation.