Thin Portion Research Articles

種々の希土類化合物を用いて粒界拡散処理したＮｄ‐Ｆｅ‐Ｂ系焼結磁石の保磁力

In order to clarify the origin of coercivity enhancement of Nd-Fe-B sintered magnets by the Grain BoundaryDiffusion Process (GBDP), microstructural observations were performed and the coercivities of magnets processed with various rare-earth oxides were investigated. Microstructural analysis using FE-EPMA revealed that Dy supplied from the magnet surface diffused into whole magnets with a thickness of 2 mm. At the center of a magnet, the Dy distribution width around a grain boundary is almost comparable to the width of the Nd-rich grain boundary phase.When rare-earth (R) oxides whose R provide higher anisotropy in R2Fe14B than that of Nd2Fe14B, are used for GBDP, the magnets showed higher coercivity than that of the control, and vice versa. Although the diffusion depth of Dy into the Nd2Fe14B grains was unclear at the center of the magnet, the relationship between the kinds of rare-earth elements used for GBDP and the resultant coercivities strongly suggests that the rare-earth elements supplied from the surface of the magnets and absorbed along the grain boundary phase may diffuse into very thin portions of the Nd2Fe14B grain surface.

Voices of the dead: complex nonlinear vocal signals from the larynx of an ultrasonic frog

Most anurans are highly vocal but their vocalizations are stereotyped and simple with limited repertoire sizes compared with other vocal vertebrates, presumably because of the limited mechanisms for fine vocal motor control. We recently reported that the call of the concaveeared torrent frog (Amolops tormotus Fei) is an exception in its seemingly endless variety, musical warbling quality, extension of call frequency into the ultrasonic range and the prominence of subharmonics, chaos and other nonlinear features. We now show that the major spectral features of its calls, responsible for this frog's vocal diversity, can be generated by forcing pressurized air through the larynx of euthanized males. Laryngeal specializations for ultrasound appear to include very thin portions of the medial vocal ligaments and reverse sexual size dimorphism of the larynx--being smaller in males than in females. The intricate morphology of the vocal cords, which changes along their length, suggests that nonlinear phenomena probably arise from complex nonlinear oscillatory regimes of separate elastically coupled masses. Amolops is thus the first amphibian for which the intrinsic nonlinear dynamics of its larynx--a relatively simple and expedient mechanism--can account for the species' call complexity, without invoking sophisticated neuromuscular control.

Imaging of ungrouted tendon ducts in prestressed concrete by improved SIBIE

The impact-echo method has been extensively applied to nondestructive evaluation of defects in concrete structures. The presence and the location of defects in concrete are estimated by identifying peak frequencies in the frequency spectra. To detect ungrouted tendon ducts, the method is known to be available. However, because post-tensioning prestressed concrete members usually have thin web portions, spectra obtained could include many peak frequencies. As a result, it is often problematic to select appropriate peak frequencies associated with the presence of ungrouted ducts. Stack imaging of spectral amplitudes based on impact-echo (SIBIE) is developed, in order to improve the impact-echo and to visually identify the locations of such reflectors as voids and defects. In the present paper, SIBIE is successfully applied to identify ungrouted metal and plastic sheaths at the hunch portion of a prestressed concrete beam. Two-dimensional dynamic BEM analysis is performed to investigate the relations between peak frequencies and locations of reflectors. At the peak frequencies in the spectra, locations of stress concentration are correlated with the response modes.

Plastic Zone Study by Means of Tri-Dimensional Finite Element Models on Fatigue Crack Closure

This paper focuses on the study of the plastic zone in fatigue crack closure based on the results obtained by means of 3D Finite Element Analysis (FEA). These results show the crack behavior through the thickness. The plastic zone is visualized and quantified. It does not correspond to the classical shape. The plastic zone in the interior surface is similar to those obtained in 2D plane strain conditions and a reduced effect of closure is observed. However, close to the external surface, 2D plane stress results are not reproduced, the plastic zone size is smaller and an important change is observed. This transition is developed in a thin external portion of the specimen and it can only be captured if a fine mesh of the thickness is done.

Voices of the dead: Complex nonlinear vocal signals from the larynx of an ultrasonic frog

Most anurans are highly vocal but their vocalizations are stereotyped and simple with limited repertoire sizes compared to other vocal vertebrates, due presumably to the limited mechanisms for fine vocal motor control. We recently reported that the call of the concave-eared torrent frog (Amolops tormotus) is an exception in its seemingly endless variety, musical warbling quality, extension of call frequency into the ultrasonic range, and the prominence of nonlinear features such as period doubling. We now show that the major spectral features of its calls, responsible for this frog’s vocal diversity, can be generated by forcing pressurized air through the larynx of euthanized males. Laryngeal specializations for ultrasound appear to include very thin portions of the medial vocal ligaments and the reverse sexual size dimorphism of the larynx being smaller in males than in females. The intricate morphology of the vocal cords, which changes along their length, suggests that nonlinear phenomena likely arise from complex nonlinear oscillatory regimes of separate elastically coupled masses. Amolops is thus the first amphibian for which the intrinsic nonlinear dynamics of its larynx, a relatively simple and expedient mechanism, can account for the species call complexity, without invoking sophisticated neuromuscular control.

Scanning and transmission electron microscope images of a suspended single-walled carbon nanotube

For the first time we perform simultaneous observations of individual single-walled carbon nanotubes using scanning electron microscope (SEM) and transmission electron microscope modes of a transmission electron microscope equipped with a scanning attachment operating at 100kV. We show that in the SEM mode both individual single-walled carbon nanotubes situated on thin Si3N4 membranes and portions of these tubes projecting far beyond the membranes can be observed. The contrast and width of the nanotube images depend on their diameter and density on a substrate. Possible mechanisms of the observed nanotube contrast are discussed.

Preparation of poly(lactic acid) composite hollow spheres containing calcium carbonates

Poly(lactic acid) composite hollow spheres containing calcium carbonate were prepared by oil-in-water emulsion evaporation to develop injectable bone substitutes incorporated with cells. The spheres were ∼1.2 mm in diameter and had a shell with a thickness in the range of 50–150 μm. The hollow in the spheres was presumed to be formed by CO 2 gas generated by the decomposition of vaterite used as a starting material. An open channel ∼800 μm in diameter was formed in the spheres by chemical etching utilizing the rapid dissolution of poly(lactic acid) at the thin portion of the shell. Cells could migrate into the hollow spheres through the open channel and attach to the inner surface.

The Impact that Hurricane Ivan (September 16, 2004) Made across Dauphin Island, Alabama

Abstract The western eye-wall of Hurricane Ivan (an upper Category 3 hurricane on the Saffir–Simpson scale) passed approximately 21 km east of Dauphin Island as it made an early morning landfall on September 16, 2004. The island experienced Category 1 hurricane (Saffir–Simpson scale) force winds and large storm waves. Ivan affected Dauphin Island in a variety of ways because of the island's morphology and proximity to nearby submerged and emergent features. The eastern end of the barrier island experienced diminished storm wave energy as a result of an emergent offshore sand island (Pelican-Sand Island), which is a portion of the shallow submerged Mobile Bay ebb-tidal delta. These offshore features absorbed most of the energy from Ivan's storm waves. The western end of the island, a thin and low-lying portion of the barrier island platform, received the full impact of the hurricane. Beach-derived sand was transported northward across this portion of the island by the action of storm waves that washed over...

Multiscale modelling in the numerical computation of isothermal non-wetting

A state of permanent, isothermal non-wetting of a solid surface by a normally wetting liquid may be achieved if the surface moves tangentially to a liquid drop that is pressed against it. Surrounding gas is swept into the space between the liquid and solid creating a lubricating film that prevents wetting. The length scales of the drop and the film are typically three or more orders of magnitude different, making numerical simulation difficult from a resolution standpoint. The present paper focuses on a hybrid approach employing lubrication theory for the thinnest portions of the gas film and numerical simulation for the liquid and outer gas phases.

Transverse correlations and plasticity in the CDW conductor NbSe3studied by X-ray microbeam diffraction

In whisker-like samples of the quasi-1D conductor NbSe 3 , the presence of longitudinal steps causes shearing of the CDW, and leads to a loss of transverse correlations. We use a microdiffraction setup with a spatial resolution of 300 nm and an angular sensitivity of 5 mdeg to image the resulting CDW contrast between thick and thin portions of the sample. Microdiffraction in the b* - c* plane shows that depinning on the thick, weakly pinned side is accompanied by the loss of diffraction intensity, demonstrating a loss of correlations in qualitative agreement with previous X-ray diffraction topography measurements 1 , but with an order-of-magnitude improvement in spatial resolution. Microdiffraction images in the a* - b* plane reveal a sharp increase in the full width at half maximum in an approximately 1 micron thick region near the step edge and a rotation of the CDW wavevector that varies with applied field. We use the extremal value of the CDW wavevector rotation to estimate the shear modulus of this electronic crystal.

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I also think that cutting balloon angioplasty is a choice only for lesions that cannot be dilated by conventional angioplasty. Incisions by the blades of the cutting balloon potentially cause side effects, including dissection and perforation of arterial wall, as we have discussed previously. To prevent these side effects, we think that the following points should be considered for the use of a cutting balloon: (1) Cutting balloons relatively undersized to the arterial diameter should be used to make the initial incisions, followed by conventional balloon dilation. (2) Considering the rigidity of the blades of the cutting balloon, a sufficient length of the renal artery for the size of the balloon should be relatively straight around the lesion. (3) The balloon should not be moved during the inflation. Especially for point (3), movement of the kidney by respiration should be avoided during the inflation of balloon. We think that intravascular ultrasonography could be beneficial for cutting balloon angioplasty. By using intravascular ultrasonography, the fibrous stricture of the resistant stenosis and the irregular vascular wall thickness of fibromuscular dysplasia could be seen before the angioplasty.1Hoshino Y. Nakamura T. Nakano A. Isobe Z. Suguta M. Tomita T. et al.Successful treatment of renovascular hypertension due to fibromuscular dysplasia by intravascular ultrasound-guided atherectomy.Nephron. 2002; 91: 521-525Crossref PubMed Scopus (4) Google Scholar The recognition of the condition of the vascular wall before the angioplasty would make it possible to place the blades of the cutting balloon on the fibrous stricture but not on the thin wall portion of the fibromuscular dysplasia. Regarding “Cutting balloon angioplasty of renal fibromuscular dysplasia: A word of caution”Journal of Vascular SurgeryVol. 42Issue 5PreviewWe read with interest the article by Tanemoto et al (J Vasc Surg 2005;41:898-901) regarding cutting balloon angioplasty of resistant renal artery stenosis caused by fibromuscular dysplasia. Cutting balloon angioplasty is being increasingly used for tight stenosis as an alternative treatment to conventional angioplasty, particularly in coronaries and arteriovenous dialysis fistulas.1 However, its use has been also described with successful results in other districts such as renal, popliteal, and supra-aortic vessels. Full-Text PDF Open Archive

WETTING PHENOMENA AND CONSTANT MEAN CURVATURE SURFACES WITH BOUNDARY

In a microscopic scale or microgravity environment, interfaces in wetting phenomena are usually modeled by surfaces with constant mean curvature (CMC surfaces). Usually, the condition regarding the constancy of the contact angle along the line of separation between different phases is assumed. Although the classical capillary boundary condition is the angle made at the contact line, configurations also occur in which a Dirichlet condition is appropriate. In this article, we discuss those with vanishing boundary conditions, such as those that occur on a thin flat portion of a plate of general shape covered with water. In this paper, we review recent works on the existence of CMC surfaces with non-empty boundary, with a special focus on the Dirichlet problem for the constant mean curvature equation.

Increasing Wet Green Strength of Alumina Body During Microfabrication by Colloidal Isopressing

Colloidal Isopressing involves formulating a slurry with a weakly attractive particle network that can be pre‐consolidated to a high relative density by pressure filtration and still retain fluid‐like characteristics. The pre‐consolidated slurry is injected into an elastomeric mold and isopressed. Isopressing rapidly converts the slurry into an elastic body that can be removed from the mold without shape distortion. Not only is this process rapid, but since the water saturated compact produced by this method does not shrink during drying, it can also be converted into a green body without a long drying period. It is demonstrated that micron‐size surface features, such as 5 μm wide channels with a depth/width ratio of 2, can be rapidly produced on the surface of alumina powder compacts. The fracturing of thin vertical portions of a micro‐patterned surface during pressure release and demolding has been an obstacle to obtaining micron‐sized features with high aspect ratios. A method is shown here that enables the fabrication of such features by strengthening the saturated isopressed body. It is shown that concentration controlled gelation of a poly(vinyl alcohol)–Tyzor® Triethanolamine Tritanate (TE) additive effectively increases the strength of the elastic, isopressed body, saturated with water, while maintaining the low viscosity of the pre‐consolidated slurry, which is required for transferring the pre‐consolidated slurry into a rubber mold prior to isopressing.

Flow-Through Anterior Thigh Flaps with a Short Pedicle for Reconstruction of Lower Leg and Foot Defects

New flow-through perforator flaps with a large, short vascular pedicle are proposed because of their clinical significance and a high success rate for reconstruction of the lower legs. Of 13 consecutive cases, the authors describe two cases of successful transfer of a new short-pedicle anterolateral or anteromedial thigh flow-through flap for coverage of soft-tissue defects in the legs. This new flap has a thin fatty layer and a small fascial component, and is vascularized with a perforator originating from a short segment of the descending branch of the lateral circumflex femoral system. The advantages of this flap are as follows: flow-through anastomosis ensures a high success rate for free flaps and preserves the recipient arterial flow; there is no need for dissecting throughout the lateral circumflex femoral system as the pedicle vessel; minimal time is required for flap elevation; there is minimal donor-site morbidity; and the flap is obtained from a thin portion of the thigh. Even in obese patients, thinning of the flap with primary defatting is possible, and the donor scar is concealed. This flap is suitable for coverage of defects in legs where a single arterial flow remains. It is also suitable for chronic lower leg ulcers, osteomyelitis, and plantar coverage.

The Thickness of the Temporal Squama and Its Implication for Transcranial Sonography

The difficult transtemporal ultrasound window is a relatively frequent occurrence. The authors assessed if the thickness of the temporal bone squama as measured in the "bone window" of the head computerized tomography (CT) scan can predict the transtemporal acoustic window. The authors retrospectively reviewed the head CTs on their bone window setting of patients in which nonimaging transcranial Dopplers (TCDs) had been performed. The thickness of the temporal squama in its thinnest portion was measured. The temporal TCD windows were graded in three classes: class 1 as good, class 2 when only a partial study is possible, and class 3 as an impossible ultrasonic window. In a case-control design, for every patient with any class 2 and 3 TCD temporal window, a patient with a class 1 window was randomly included from the same time period. Fifty-five temporal bones (56%) were class 1, 17 (17%) were class 2, and 27 (27%) were class 3. Bone thicknesses (in mm, mean +/- SD) were greater in those with poorer windows: class 1 = 2.67 +/- 0.70, class 2 = 4.06 +/- 0.56, and class 3 = 5.04 +/- 1.06, P < or = .0001 by Cusick's nonparametric test of trend. Temporal squama thickness of > or = 5 mm portends 86% sensitivity, 90% specificity, 70% positive predictive value, and a positive likelihood ratio of 8.6 for a class 3 transtemporal ultrasound window. Measurement of temporal bone thickness on the bone window setting of the head CT scan may be useful in identifying patients who are poor candidates for transcranial ultrasound.

Endometriosis-related pneumothorax: clinicopathologic observations from a newly diagnosed case

thymic masses by indium-111-DTPA-D-pentetreotide scintigraphy. J Nucl Med. 1998;39:634-9. 22. Reisiene T, Bell GI. Molecular biology of somatostatin receptors. Endocr Rev. 1995;16:427-42. 23. Patel YC, Srikant CB. Subtype selectivity of peptide analogs for all five cloned human somatostatin receptors (hsstr 1-5). Endocrinolgy. 1994;135:2814-7. 24. Filosso PL, Ruffini E, Oliaro A, Papalia E, Donati G, Rena O. Long-term survival of atypical bronchial carcinoids with liver metastases, treated with octreotide. Eur J Cardiothorac Surg. 2002;21: 913-7.

Shock absorbing construction for motorcycles

The invention provides a shock absorbing construction for motorcycles that has a dimensional standard suitable for practical use and can absorb the impact sufficiently. A shock absorbing member(21)comprises a plurality of cavities(35...)and reinforcing ribs(30...)for dividing adjacent cavities (35, 35), and all or some(30a-30g)of these reinforcing ribs(30...)are formed with thinner portions (35a-35g)respectively. A shock absorbing member(21) projecting forward from the front wheel(13)is provided so that the shock absorbing member(21)absorbs the impact by being collapsed.

The standard maze-III procedure

The standard maze-III procedure

Glomeruli and renal tubules are restricted to the cranial kidney of the adult estuarine Sphoeroides testudineus

The kidney of the pufferfish Sphoeroides testudineus, an abundant tropical euryhaline estuarine species of the western Atlantic Ocean found in southern Brazil (in salinities ranging from 0 to 34) has a large and laterally spread cranial red portion, and a very thin and pale caudal portion. When studied under light and transmission electron microscopy, the cranial kidney displayed glomeruli and renal tubules surrounded by haematopoietic tissue. These tubules appeared to drain into a single large convoluted collecting duct with a wide lumen and thick pseudostratified epithelium, the mesonephric duct, which constituted the sole structure of the caudal kidney. Apical microvillae were viewed in the renal tubules, as well as in the mesonephric duct. Basal mitochondria and membrane infoldings were observed in the renal tubules. Abundant more basally‐located mitochondria and electron‐dense vesicles, mainly in the apical cytoplasm, were observed along the entire length of the mesonephric duct. Aposomes (blebs) were frequently observed in the mesonephric duct, both by light‐ and electron‐microscopy. This euryhaline estuarine pufferfish has thus been revealed to possess a rare type of kidney.

Dynamic observation of dislocation-free plastic deformation in gold thin foils

Ductile fracture of metals produces a thin foil portion, which is observable by transmission electron microscopy, at the fractured edge. The thin foil portion shows unusual deformation microstructure, which contains no dislocations, but contains vacancy-type point defect clusters at extraordinarily high density. Dynamic observation of the deformation process revealed that these defect clusters are produced in the portion of local heavy deformation; however, no dislocation motion was observed during the course of the heavy plastic deformation, constituting direct evidence that the unusual deformation microstructure is produced by plastic deformation without dislocations. Also, the deformation was found to involve 14% elastic deformation, indicating that the dislocation-free plastic deformation occurs under an extraordinarily high internal stress level of more than 10 GPa, which is comparable to the ideal strength of metals. Furthermore, during the dislocation-free plastic deformation, equal-thickness fringes were found to disappear temporarily, suggesting that instability of crystalline state under extraordinarily high internal stress level is a key factor for the mechanism of dislocation-free plastic deformation.