The present study targets four representative GNBs (Geometrically Necessary Boundaries) in terms of their unified and quantitative evaluations based on the field theory of multiscale plasticity ...(FTMP). Discrete dislocation dynamics simulations on GNBs 2, 3, 4 and 7, whose details about the consisting dislocations have been experimentally identified and theoretically evaluated by Hong, Winther, et al., are conducted. Applying the FTMP-based duality diagram representation scheme to the formation processes reveals a systematic interrelationship that further governs the stability of the GNBs, i.e., all the GNBs exhibit a common tendency to converge ultimately to a single master curve. This leads us to propose a postulate about the stability/instability criterion that involves their dynamic interactions with external disturbances.
This study attempts to quantitatively evaluate the apparent reduction in elastic moduli, generally observed in metallic materials during unloading and/or cyclic elasto-plastic deformation, based on ...Field Theory of Multiscale Plasticity (FTMP). Two typical arrangements of bowing-out dislocation segments that yield mutually-distinct trends are examined by utilizing the FTMP-based duality diagram representation scheme. It is demonstrated that not only the scheme allows us to visualize the associated energy flow but also to correlate the resultant apparent shear modulus reduction rate in a unified manner by the duality coefficient measured on the duality diagrams. The scheme is demonstrated to be effective also for more complex cases accompanied by pinning/unpinning and the following relaxation processes.
Diamond-like carbon (DLC) can be effectively coated on polymer surfaces in order to modify polymers for highly functionalized materials. DLC films have been widely used for many industrial ...applications due to their outstanding physical properties such as high hardness, wear resistance and biological compatibility. Polymers, on the other hand, can create soft, flexible, highly absorbent and cost-effective materials by selecting or controlling their molecular structures. The DLC films coated on such polymer substrates have been investigated and extensively used because recently, quite a few applications of the polymer–DLC composites to e.g. gas barrier films and biocompatible medical devices have been proposed. In this article, we discussed the barrier properties, especially the gas barrier properties and the biocompatibility of DLC-coated polymers, after summarizing the fundamentals of DLC and polymers, followed by the explanation as to the adhesion and fracture behavior of DLC and polymers, which is crucial for the creation of a new polymer–DLC composite.
► This review article deals with the properties and applications of DLC films coated on polymers. ► Fundamental properties of DLC, polymers, and polymer-DLC were discussed. ► Polymer–DLC composites for gas barrier films and biocompatible medical devices were proposed. ► A new drug-eluting system utilizing DLC-coated polymers was introduced.
Retrocaval ureter is a rare congenital anomaly resulting from anomalous development of inferior vena cava (IVC) and not from anomalous of the ureter. The anomaly always occurs on the right side due ...to regression of right supracardinal vein and persistence of right posterior cardinal vein. Retrocaval ureter tends to be associated with various vena cava anomalies because of the embryogenesis. We aimed to identify the prevalence of associated congenital venous anomalies (CVA) resulting from cardinal vein development in adults with retrocaval ureter using computed tomography (CT) images.
The study included 22 adults with retrocaval ureter. We evaluated CT findings and determined the incidence of associated CVA using thin slice data sets from CT scanner with 64 or more detectors. We compared the prevalence of CVA in the retrocaval ureter group (mean age: 57 ± 19 years) and in the control group of 6189 adults with normal ureter (mean age: 66 ± 14 years).
In the retrocaval ureter group, 4 (18.2%) adults had CVA including double IVC, right double IVC, preisthmic IVC with horseshoe kidney, and preaortic iliac confluence. One of 2 adults with preaortic iliac confluence had right double right IVC. In the control group, 49 (0.79%) adults had CVA including 37 double IVC, 11 left IVC, and 1 IVC interruption azygos continuation. Fifteen horseshow kidneys were found. The prevalence of associated CVA in the retrocaval ureter group was higher than that in the control group (p < 0.001).
Retrocaval ureter is frequently associated with CVA. Various CVA with retrocaval ureter could happen because of abnormal development of not only the right posterior or supra cardinal vein but also other cardinal veins.
The mechanism of biomaterial-associated thrombosis has not been fully elucidated. It is believed that surface roughness of biomaterials is a key factor in influencing thrombogenicity. Diamond-like ...carbon (DLC) is being considered for widespread clinical use as a surface coating for cardiovascular devices. We previously reported that fluorine doping in DLC films (F-DLC) markedly inhibits platelet adhesion and activation in human blood. To evaluate the effects of surface roughness of coatings on thrombus formation, DLC and F-DLC films were deposited on the three different roughness-controlled polycarbonate (PC) substrates, and platelet adhesion and activation was investigated on each substrate. The surface roughness of DLC-coated PC and F-DLC-coated PC ranged from 4.1 nm to 97 nm. In this range, there were no significant differences in the platelet-covered area among the three grades of differing surface roughness for each coated surface. However, evaluation of the F-DLC films showed significant reductions in platelet adhesion and activation when compared with DLC films for every grade of roughness, suggesting that the inherent chemical characteristics of the surface, such as wettability, interfacial free energy and higher ratios of albumin/fibrinogen adsorption, might be more important in the mechanism of F-DLC non-thrombogenicity.
A search for sub-eV scalar fields coupling to two photons has been performed via four-wave mixing at a quasi-parallel laser collider for the first time. The experiment demonstrates the novel approach ...of searching for resonantly produced sub-eV scalar fields by combining two-color laser fields in the vacuum. The aim of this paper is to provide the concrete experimental setup and the analysis method based on specific combinations of polarization states between incoming and outgoing photons, which is extendable to higher-intensity laser systems operated at high repetition rates. No significant signal of four-wave mixing was observed by combining a 0.2
$\mu $
J/0.75 ns pulse laser and a 2 mW CW laser on the same optical axis. Based on the prescription developed for this particular experimental approach, we obtained the upper limit at a confidence level of 95% on the coupling–mass relation.
Effects of doping with fluorine to diamond-like carbon (DLC) films on the antithrombogenicity were investigated by changing its content. Fluorinated DLC (F-DLC) films were prepared on silicon (Si) ...substrates using radio frequency (RF) plasma enhanced chemical vapour deposition (CVD) by changing the ratio of hexafluoroethane (C
2F
6) and acetylene (C
2H
2). The contact angle measurements of human whole blood droplet on Si, DLC and F-DLC were 24.2°, 60.8° and 95.3°, respectively. Furthermore, the static evaluation of F-DLC films incubated with platelet-rich plasma (PRP) showed dramatic reduction of platelet adhesion and activation on the surface. It was found that the addition of fluorine into DLC films much improved antithrombogenicity, which was clearly shown by scanning electron microscopy (SEM) with statistical analysis. F-DLC coating can be a great candidate for developing antithrombogenic surfaces in blood contacting materials.
Pyramid-type antireflective subwavelength structures for large-diameter (
>
30
cm
) silicon lenses are promising for broadband astronomical observations. The refractive index and dielectric loss ...tangent of the lens material, columnar crystal silicon which is manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd., were measured at around 30 K using a Martin–Puplett-type Fourier transform spectrometer. The measured refractive index and dielectric loss tangent between 200 GHz and 1.6 THz were
∼
3.42 and 1–
5
×
10
-
4
, respectively. Three different pyramid-type structures with a period of
265
μ
m
and depth of
600
μ
m
were simulated to obtain their reflectance using an electromagnetic field simulator, HFSS. The structures were fabricated on both sides of a 100-mm-diameter plane-convex lens made of columnar crystal silicon with a 150-mm radius of curvature using a metal-bonded V-shaped blade and a dedicated three-axis machine. The fabrication errors in the period and depth were less than
10
μ
m
. The reflectance of the lens flat surface was measured using a vector network analyzer to be between
-
8
and
-
17
dB in the range of 110–170 GHz, which was consistent with the result from the simulation.
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