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11.
Takeshi Kikuchi Yoshizo Kitami Masato Yokoyama Hiroshi Sakai 《Journal of Materials Science》1989,24(12):4275-4278
The phase equilibria in the pseudo-binary system Bi2O3-TeO2 at 600° 950° C in air were examined by solid-state reaction techniques and X-ray powder diffraction method. Four pseudo-binary compounds appeared, i.e., -Bi2O3 type solid solution having a compositional range of (1-x)Bi2O3·xTeO2 wherex=0 0.4 a new compound Bi6Te2O15 which has an orthorhombic cell of a=2.27(4) nm, b=1.06(1) nm and c = 0.539(8) nm, 2Bi2O3 · 3TeO2, and an unidentified phase Bi2O3·2TeO2. The formation of the phase Bi6Te2O15, in which all the Te ions are hexavalent, was confirmed by the thermogravimetry and by the Mössbauer spectra. The liquidus curves for whole system were determined by DTA method. 相似文献
12.
Summary Inside a microporous polyethylene film, 2-acrylamido-2-methylpropane sulfonic acid was graft polymerized by ultraviolet irradiation. A humidity sensor was fabricated by depositing gold electrodes on both sides of the grafted film. The impedance was measured as a function of humidity for the acid and alkali salts of sulfonate. The sensor has long term stability and is resistant to water. 相似文献
13.
Polytetramethylene glycol (molecular weight range 1000–8000) was prepared by the polymerization of tetrahydrofuran (THF) using a binary catalyst system of fuming sulfuric acid and perchloric acid. When 28% fuming sulfuric acid alone was used as the catalyst, the average molecular weight of polymer was low, the maximum value being 1000–1100. By the combination of fuming sulfuric acid with a small amount of perchloric acid, the average molecular weight of the polymer was increased to about 8000. Furthermore, the molecular weight was readily controlled in the range of 1000 to 8000 by varying the amount of the binary catalyst. 相似文献
14.
Requirements and microstructural design criteria for employing silicon nitride in long-term structural applications at elevated temperatures are discussed according to fracture mechanics concepts. Three least engineering parameters are considered: lifetime, flaw-tolerance and deformation under stress. “Ductile” materials are found by exploitation of small-scale crack-tip yielding which arises from the softening of their grain-boundary phase. These materials, however, are likely to exhibit poor deformation resistance. Materials with a “strong” grain boundary generally show a superior deformation behaviour but are liable to brittle fracture and static-fatigue strength degradation unless shielding mechanisms in the crack-wake be operative. The present analysis evaluates and compares these two classes of materials and the respective approaches commonly followed for their densification. 相似文献
15.
Foam-breaking with a rotating disk mechanical foam-breaker (MFRD) was studied for a foaming system containing a diluted detergent solution in a laboratory sparged agitated vessel. The change of the foam-breaking capacity of the MFRD by varying the air sparge rate, the working volume and the impeller speed or the disk diameter was measured. Based on these measurements, empirical equations are presented for predicting the critical foam-breaking regions of the MFRD fitted with the agitated vessel. The operational range where foam-breaking with the MFRD can be carried out effectively and economically is also discussed. 相似文献
16.
17.
Hideaki Adachi Toshifumi Satoh Masahiro Sakai Koichi Mizuno Kentaro Setsune 《Journal of Superconductivity》1994,7(4):737-741
Epitaxial multilayer thin films of infinite-layer (Sr, Ca)CuO2 and perovskite (Sr, Ca)RuO3 have been prepared on (100) SrTiO3 substrates by multitarget rf magnetron sputtering. X-ray diffraction analyses revealed that the multilayer structure of (Sr, Ca)CuO3/(Sr, Ca)RuO3 was successfully fabricated with a minimum layer thickness of 20 Å. Transmission electron microscopy measurements of the multilayers indicated that there was no dislocation which normally exists in single-layer films with an infinite-layer structure. Resistivities of multilayer films at room temperature ranged from 1 to 10 m cm and showed semiconductor-like dependence against the temperature. 相似文献
18.
A data-driven design method for a cascade control system is proposed. The cascade control system consists of inner and outer loops, where the control interval of the outer loop is an integer multiple of the inner loop; hence, the system is a dual-rate system. In the proposed method, controllers in the inner and outer loops are designed based on one-shot data. In such a dual-rate cascade system, since the controllers are designed using different data-rate signals, the lifting technique is applied to align the dual-rate data. To show its effectiveness, the proposed method is compared with a conventional single-rate cascade control method, and numerical simulations and experiments are presented to examine servo and regulation performance. 相似文献
19.
MD Dake DC Miller RS Mitchell CP Semba KA Moore T Sakai 《Canadian Metallurgical Quarterly》1998,116(5):689-703; discussion 703-4
OBJECTIVE: Our goal was to determine whether endovascular stent-grafting is feasible and effective for patients with aneurysms of the descending thoracic aorta. METHODS: Starting in July 1992, we conducted a prospective, uncontrolled clinical trial in 103 patients (mean age 69 years [range 34-89 years]) who underwent endovascular treatment of aneurysms of the descending thoracic aorta using a custom-fabricated, self-expanding stent-graft device. Follow-up was 100% complete and averaged 22 months. Sixty-two patients (60%) were judged not to be reasonable candidates for a conventional "open" surgical procedure. RESULTS: Complete thrombosis of the aneurysm was ultimately achieved in 86 (83%) patients. The early mortality rate was 9% +/- 3% (+/- 70% CL). Multivariable analysis revealed that myocardial infarction or stroke was linked with a higher likelihood of early death (P = .001). Early serious complications included paraplegia in 3% +/- 2% and stroke in 7% +/- 3%. Actuarial survival estimates at 1 year and 2 years were 81% +/- 4% and 73% +/- 5% (+/- 1 SE), respectively; being judged not to be a surgical candidate portended a higher probability of death (P = .003). According to the intent-to-treat principle, "treatment failure" (including all late sudden unexplained deaths) occurred in 38 patients; 53% +/- 10% of patients were free from treatment failure at 3.7 years. Stent-graft related complications occurred commonly and were linked with several anatomic, technical, and patient-related risk factors. CONCLUSIONS: This 5-year clinical trial involving use of a "first generation" device indicates that endovascular stent-grafting of descending thoracic aortic aneurysms is feasible with acceptable medium-term results. More refined, commercially developed devices available today offer less traumatic and more precise stent-graft deployment; these major technical advantages, coupled with important lessons we have learned over time and better patient selection, should be associated with more salutary clinical results in the future. 相似文献
20.
I Ozaki K Yamamoto T Mizuta S Kajihara N Fukushima Y Setoguchi F Morito T Sakai 《Canadian Metallurgical Quarterly》1998,43(6):837-842
Distortion-product otoacoustic emissions (DPOAEs) have been shown to be ideally sensitive to interruptions of the cochlear blood flow. However, a 15- to 30-second latency typically occurs between cessation of circulation and measurable DPOAE level changes. DPOAEs can also be characterized by phase measures. The aim of the present study was to determine in 10 rabbits the effects on DPOAE phase of repetitively compressing the internal auditory artery. In contrast to the delays measured by DPOAE level, phase changes were detected 1 to 5 seconds after internal auditory artery compression. These data suggest that the essentially "real time" monitoring of cochlear function with DPOAE phase can be used to ensure hearing preservation during surgery involving the porus acousticus and skull base. 相似文献