Circular Degree Research Articles

Influence of Ce, K, and Na on spheroidization of eutectic carbides in low-tungsten white cast iron

AbstractTungsten alloy white cast iron (TAWCI) exhibits strong brittleness and a narrow application scope. The influences of Ce, K and Na on the microstructure and performance of TAWCI have been studied, and the idea to estimate the spheroidization effect of carbides using circular degree (C.D.) is put forward. The results show that eutectic carbides turn from network into sphericity after the modification. Carbide is refined and uniformly distributed and theC.D. of eutectic carbides increases. The mechanism of carbide spheroidization has been analyzed. The impact toughness and wear resistance of TAWCI obviously improves with the rise ofC.D. of carbides. The service life of a modified TAWCI roll is 35 % higher than that of high-chromium cast-iron roll, its production cost is reduced by 25 %.

Chiral recognition via a stereodynamic vanadium probe using the electronic circular dichroism effect in differential Raman scattering.

Intermolecular interactions sensitive to chirality occur in many biological events. We report a complex formation between a versatile vanadium-based probe and a chiral co-ligand monitored via the combination of electronic circular dichroism (ECD) and Raman scattering. This "ECD-Raman" effect was discovered relatively recently and can be measured using a Raman optical activity (ROA) spectrometer. Simulated spectra based on experimental ECD and degree of circularity (DOC) values agree with the observed ones. Sensitive recognition of the chiral enantiopure co-ligand is thus enabled by a combination of resonance of the excitation light with the diastereoisomeric complex, co-ligand complexation, circular dichroism, and polarized Raman scattering from the achiral solvent. Relatively dilute solutions could be detected (10-4 mol dm-3), about 1000× less than is necessary for conventional ROA detection of the pure co-ligand and comparable to concentrations needed for conventional ECD spectroscopy. The results thus show that differential ECD-Raman measurements can be conveniently used to monitor molecular interactions and molecular spectroscopic properties.

Influence of Ce, K, and Na on spheroidization of eutectic carbides in low-tungsten white cast iron

Tungsten alloy white cast iron (TAWCI) exhibits strong brittleness and a narrow application scope. The influences of Ce, K and Na on the microstructure and performance of TAWCI have been studied, and the idea to estimate the spheroidization effect of carbides using circular degree (C.D.) is put forward. The results show that eutectic carbides turn from network into sphericity after the modification. Carbide is refined and uniformly distributed and the C.D. of eutectic carbides increases. The mechanism of carbide spheroidization has been analyzed. The impact toughness and wear resistance of TAWCI obviously improves with the rise of C.D. of carbides. The service life of a modified TAWCI roll is 35 % higher than that of high-chromium cast-iron roll, its production cost is reduced by 25 %.

Synergistic Tenotomy-related Changes in Circumference of Rat Soleus Muscle Fibers

2326 We hypothesized that sarcolemmal area of a muscle fiber, as well as myo-tendious junction, would relate force output and that it would increase after continuous overload. PURPOSE: The purpose of this study was to examine the change of sarcolemmal area of soleus muscle fibers following tenotomy of plantaris and gastrocnemius muscles using a staining method with anti-dystrophin antibody. METHODS: Male Wistar rats were randomly assigned into tenotomy (A) group and control (B) group. In the A group, the gastrocnemius and plantaris muscles of left hind limbs were surgically tenotomized. After 10 days, the soleus muscles of both legs were rapidly dissected. The mean cross sectional area (CSA) and circular degree (CD) of muscle fibers were measured on the cross section stained with anti-dystrophin antibody. The CD represents the perimeter per CSA of a muscle fiber. RESULTS: The CSA was significantly larger in the A group than in the B group (2945 ± 348μm2 vs. 2460 ± 236μm2, p<0.05). The CD was not significantly changed between both groups (0.691 ± 0.010 vs. 0.685 ± 0.020, p>0.05). CONCLUSIONS: The soleus muscle fibers hypertrophied with continuous overload due to tenotomy of synergistic muscles. However their mean CD did not changed. The results suggest that sarcolemmal area of a muscle fiber would not be a determinant to force transmission.

IS POLYGONAL PATTERN OF CROSS-SECTIONAL MUSCLE FIBER RELATED TO METABOLIC AND CONTRACTILE PROPERTIES WITH AGING?

When a skeletal muscle is viewed in cross-section, various polygonal fibers make a geometrical pattern, called Dirichlet domain. However, little has been done with distribution and changes in polygonal patt erns of cross-sectional muscle fibers with aging. PURPOSE The purpose of this study was to examine polygonal patterns of cross-sectional muscle dominated in soleus muscle with aging. METHODS In six young (6 wk old, Y group) and six young adult □@(10 wk old, YA group) male Wistar Kyoto rats, fiber type was histochemically classified in soleus muscle. The cross-sectional area of muscle fiber (CSA) was morphometrically determined. The polygon of cross-sectional muscle fibers was calculated as a circular degree (C.D.) by using the formula: C.D. = 4fIS/l 2, where 1 is peri meter and S is cross-sectional area of fiber (circle=1.0, hexagon=0.9, square=0.8, triangle=0.6). RESULTS The C.D. for slow twitch fiber (SO) was in greater in Y group than YA group (0.724 ±0.067 vs. 0.680 ±0.072, P □ f > 0.001), whereas CSA was smaller in Y group than YA group (1681 ±379fEm vs. 2321 ±665fEm2, P □f > 0.001). In the FOG (fast twitch fiber, oxidative and glycolytic) fibers, Y group also demonstrated a greater circular degree than YA group (0.717 ±0.067 vs. 0.669 ±0.082, P □f > 0.001), while CSA for FOG fibers was also smaller in Y group than YA group (1350 ±224fEm 2vs. 2126 ±590fEm2, P □ f > 0.001). Growth decreased C.D. in SO and FOG fibers and became more polygonal, whereas both muscle fiber sizes increased with age. CONCLUSION These data suggest that the growth-related shift to more polygonal pattern s increased metabolic surface areas of fibers. For contractile property, more polygonal pattern may decrease a balanced tension in a bundle of microfilaments due to mo re irregular polygons, wh ereas muscle fibers might enhance functional diversity.

The geometric effect of scattering space on the critical degree of circularity for Xe fluid

The geometric effect of scattering space are numerically discussed on the degree of circularity (DC) for Xe fluid in the critical region. The results show that the effect becomes very important, as the system approaches to the critical point and the DC can be another tool to study the critical scattering of a fluid.

On the scattering phenomena for various kinds of polarized light in a nonpolar fluid composed of chiral molecules

The explicit result of the coefficients of the Mueller matrices, which express the Stokes parameters of single and double scattered lights in term of the parameters of the corresponding incident light, are obtained for a nonpolar fluid composed of chiral molecules with the aid of the Ornstein–Zernike form for the correlation function of density fluctuations. The explicit results show that any higher order multiple scattering satisfies the principle of symmetry and law of reciprocity. From the matrices some scattering phenomena for six kinds of completely polarized light in a nonpolar achiral fluid are discussed in the cases of far from and near the critical point. While the degrees of circularity (DCs) give identical information with the circular intensity differences (CIDs) in the region far from the critical point, the critical DCs for circularly polarized lights is quite different from the critical CIDs. The theoretical result of DCs for the circularly polarized lights indicates that the DCs can be other effective experimental tools to measure the critical scattering of a fluid.