Ultrasonic evaluation of interlayer interfacial stiffness of multilayered structures

A procedure for the ultrasonic evaluation of the interlayer interfacial stiffness of multilayered structures is proposed. As a theoretical background to this proposal, the elastic wave propagation in a multilayered structure, in which the layers are bonded with spring-type interfaces, is analyzed theoretically based on the transfer-matrix method. Using the notion of the Bloch phase which characterizes wave transmission in the corresponding infinite periodic structure, some explicit relations are derived for the reflection coefficient of the multilayered structure. Based on the features clarified theoretically, the interlayer interfacial stiffness of the multilayered structure can be evaluated from the locations of local minima and maxima of the amplitude reflection spectrum. By numerical analysis, the proposed procedure is shown to apply even when the viscous property of the layers is not known precisely, and when a transient waveform of a limited length is used. Using the proposed procedure, the stiffness of interlayer resin-rich regions in a carbon-epoxy cross-ply composite laminate is identified from the experimental reflection spectrum. The identified stiffness is shown to lie within the range as expected from the micrographic observation and a simple estimate for a thin resin layer

日本史への封建制概念の適用について

Man wender ohne Zweifel auf die Geschichtsbeschreibung Japans den Begriff Feudelismus an. Aber betreffs diese Anwendung wäre es zu bemerken, daß der Begriff einerseits aus dem europäischen Mittelalter stammt, und daß er andererseits die Übersetzung des in der chinesischen Geschichte wurzelnden Wortes hokensei ist. Diese Übersetzung ergab sich aus den folgenden Varhältnissen: erstens fand eine Reihe von Intellektuellen des Tokugawa-Japans zwischen dem zeitgenössischen Regime und dem in der chinesischen Literatur geschilderten hokensei gemeinsame Züge, und zweitens die persönlich das Tokugawa-Japan kennenlernten, in ihm eine Reihe von an den europäischen Feudalismus erinnernden Zügen.Noch weiter fanden einige Historiker des Meiji-Japans zwischen dem japanischen und europäischen Mittelalter "auffallend ähnliche Züge". Daraus ergab sich, daß das Wort hokensei als der geschichtswissenschaftliche Terminus galt, dessen Modell selbstverständlich der europäische Feudalismus war.Im Bezug auf die Feudalismus (hokensei)- Auffassung in Japan ist zugleich nicht überzusehen, daß die Intellektuellen des TokugawaßJapans die Anfangszeit des hokensei Japans mit der Entstehung der SamuraißRegierung identifizierten. Diese Identifizierung blieb anch im Kopf der Historiker des modernen Japans--bewußt oder unbewußt, mehr oder weniger--dauerhaft, so daß man dazu neigte, Frühneuzeit (des Tokugawa-Japans), die zu ihm in verfassunggeschichtlicher Hinsicht ganz unterschiedlich war, unter den einen Begriff hokensei gewaltsam zu subsumieren.Zwar gab es auch Historiker, die den Unterschied zwischen den beiden Zeiten erkannten, aber sie denteten ihn als die Verschiedenheit auf den Entwicklungsstufen des hokensei an; sie sahen das Mittelalter als die ungereifte Stufe der Feudalität an.Der Gewinn der positiv-geschichtswissesnschagtlichen Forschungen deutet aber die Schwierigkeit an, zwischendem somit als die gereifte Stufe des hokensei angesehenen Tokugawa-Japan und dem feudalen Europa ähnliche Züge zu finden. Eben aus dieser Schwierigkeit ergibt sich in der zu lassen, um das wenig feudale Tokugawa-Japan unter ihn zu subsumieren.Die Beseitigug der Identifizierung der Zeit des hokensei mit der Samurai-Regierung wäre unentbehrilich, um die der Meiji Restauration vorangegangenen Zeit "aus dem internationalen Gesichtspunkt" richtig zu erkennen und zu beschreiben

Studies on the Fluorine Generation by Fused Salt Electrolysis of KF·2HF at about 100°C

Fluorine generation by fused salt electrolysis of KF・2HF at medium temperature of about 100°C was studied from view points of anodic polarization and anode effect. At first, equipment for manufacturing anhydrous HF and a 100 Amp fluorine cell were designed and operated. Various anodic materials (carbons with different grades of graphitization, nickel, C-Cu alloy etc.) were used and the suitable materials for the fluorine generation were selected. Some additional agents (LiF, AlF₃, NiF₂ etc.) were added to the electrolyte and their effects to anodic polarization were considered from various points. Anodic polarization (or the degree of anode effect) have been proved to have the relation with the wettability of anode by electrolyte. Wettabilities of each electrode were measured by the measurement of sizes, forms and contact angles of bubbles on the anode surface by microphotographic observation. The relation between the wettability and limiting current densities at which anode effect starts, was discussed

Anomalous Change of y\u27 and z in Na_x(H?O)_zCoO?・y\u27H?O at x ? 0.33

Abstract: We prepared some Nax(H?O)zC0O?・yH?O with BLH single phase and examined the Na content (x), H?O content (z)and H?O content (y). Nax(H?O)zC0O?・yH?O with BLH single phase and 0.28≦x≦0.36 were prepared by changing the amount of Br? used. The drastical changes in the c-axis length and z, Co valence, y around x=0.33 were observed, strongly suggesting that there exists a phase transition here

Preparation of conducting In-based copper oxide by annealing under high pressure

By annealing InBa_2CuO_4.44 in oxygen at a pressure of 60MPa, a new conducting cuprate InBa_2CuO_4.54 with having a- and c-axis lengths of 4.190A and 8.363A was formed. Its crystal structure was refined by the X-ray Rietveld analysis method. The factors R_wp, R_e, and S were 9.11%, 9.12%, and 1.0, respectively, indicating that the refined structure is an appropriate one. There were four distinct differences between InBa_2CuO_4.44 and InBa_2CuO_4.54. The first was an increase in the oxygen occupancy in the CuO_2 plane; the oxygen occupancy in the CuO_2 plane increased from 26.5% to 27%. The second was a drastic increase in the c-axis length from 8.09A to 8.36A . The third was the inter-substitution of In and Cu. About 35% of In and Cu atoms were substituted each other in the InBa_2CuO_4.54. The fourth was a drastic decrease in the electrical resistivity; the resistivity at room temperature decreased from 28.8MΩcm to 90.3kΩcm. These differences are discussed in connection with the oxygen content in the InBa_2CuO_y.　PACS 74.72.Jt　　key words: CuO_2 layer, Cu valence, high pressure synthesis, nBa_2CuO_y, oxygen content, tetragonal phase, orthorhombic phase

Ultrasonic wave transmission and bandgap in multidirectional composite laminates with spring-type interlayer interfaces

The ultrasonic wave transmission through multidirectional composite laminates is studied theoretically by accounting for the effect of thin interlayer resin-rich regions based on the spring-type interface model. Using the stiffness-matrix method, the energy transmission spectrum of the longitudinal wave impinging obliquely on cross-ply and quasi-isotropic laminates immersed in water is calculated. The location and bandwidth of the frequency ranges where the transmissivity becomes vanishingly small are shown to be significantly influenced by the incident angle, the laminate lay-up, and the interlayer interfacial stiffnesses. By examining the energy flux density of partial waves inside the laminate, these frequency ranges are shown to be the bandgaps due to the constructive interference of scattered waves from the interlayer interfaces. The mode combination causing the interference is found to vary remarkably with the bandgap location. Furthermore, the interference in the finite laminate structure is shown to occur in almost the same manner as the Floquet wave does in the infinitely extended laminate structure. The energy transmission spectrum is experimentally measured for 16-ply carbon/epoxy cross-ply and quasi-isotropic composite laminates using the through-transmission technique. The transmission and bandgap characteristics observed in the experimental results are reasonably reproduced by the present theory incorporating the interlayer resin-rich regions

Acute Exacerbation of Pulmonary Fibrosis in Syndrome of Combined Pulmonary Fibrosis and Emphysema Following Lung Surgery : A Report of Two Cases

We herein report two cases of an acute exacerbation of pulmonary fibrosis in the syndrome of combined pulmonary fibrosis and emphysema (CPFE) following lung surgery, and also review the relevant literature. One is a 76-year-old man, who had been diagnosed with CPFE and lung cancer and undergone lobectomy. He was admitted to our hospital because of aggravation of dyspnea 50 days after lung surgery. The other is a 69-yearold man who had been diagnosed with pulmonary bulla, pulmonary emphysema and idiopathic interstitial pneumonia at 53 years old and was complicated by lung cancer. He underwent right lower lobectomy and presented with slight fever and desaturation 18 days after lung surgery. In both cases, chest computed tomography showed diffuse bilateral ground-glass opacities superimposed on preceding reticular opacities in the lower lung field. They were diagnosed as acute exacerbation of pulmonary fibrosis in CPFE.A strict followup is required, because the prevalence of lung cancer may be higher, and acute exacerbation may occur following lung surgery in CPFE patients. HRCT plays an important role in evaluating the occurrence of lung cancer at an early stage and for determining whether there is an acute exacerbation of pulmonary fibrosis in CPFE patients.Article信州医学雑誌 60(3): 149-156(2012)journal articl

Cancer Stem Cell Microenvironment Models with Biomaterial Scaffolds In Vitro

Defined by its potential for self-renewal, differentiation and tumorigenicity, cancer stem cells (CSCs) are considered responsible for drug resistance and relapse. To understand the behavior of CSC, the effects of the microenvironment in each tissue are a matter of great concerns for scientists in cancer biology. However, there are many complicated obstacles in the mimicking the microenvironment of CSCs even with current advanced technology. In this context, novel biomaterials have widely been assessed as in vitro platforms for their ability to mimic cancer microenvironment. These efforts should be successful to identify and characterize various CSCs specific in each type of cancer. Therefore, extracellular matrix scaffolds made of biomaterial will modulate the interactions and facilitate the investigation of CSC associated with biological phenomena simplifying the complexity of the microenvironment. In this review, we summarize latest advances in biomaterial scaffolds, which are exploited to mimic CSC microenvironment, and their chemical and biological requirements with discussion. The discussion includes the possible effects on both cells in tumors and microenvironment to propose what the critical factors are in controlling the CSC microenvironment focusing the future investigation. Our insights on their availability in drug screening will also follow the discussion