Difference of histology and elemental composition of the cervical enamels among human permanent teeth

The purpose of this study is to clarify the difference of histology and elemental composition of the cervical enamels among the human permanent teeth. The re-ground surfaces at the cervical enamels of them were observed under scanning electron microscopy (SEM). The contents of seven elements were analyzed quantitatively with electron probe microanalyzer (EPMA). The widths of the rod sections at the cervical enamels were larger than those at the cuspal enamels. The rod sections at the mesial cervical enamels in the incisors were more obscure and more decayed by acid solution than those in the premolars and molars. The calcium and phosphorus contents of the cervical enamels were significantly lower than those of the cuspal enamels. The carbon content of the cervical enamels was significantly higher than that of the cuspal enamels. The calcium and phosphorus contents of the cervical enamels were the significantly highest in the premolars. The carbon and sodium contents of the cervical enamels were significantly highest in the premolars. It is thought that the calcification level is lower, while the content of organic matter is higher at the cervical enamels than those at the cuspal enamels. It is considered that the sodium causes high calcification.     

Note on the existence regions for eigenvalues of the solution to the discrete Lyapunov matrix equation

Upper and lower bounds for each eigenvalue of the solution to the discrete Lyapunov matrix equation have been reported (Mori et al. 1982 b). A generalization of this result will be presented in this note.     

Bound for radius of stability-preserving hypersphere in parameter space for Schur polynomials

For Schur polynomials with perturbed coefficients, a lower bound is derived for the radius of the hypersphere in the parameter space, within which the perturbed polynomials retain the Schur property. The result is obtained via the Lyapunov matrix equation and is expressed in terms of the size of the solution lo the equation This enables us to estimate the allowable size of the perturbation simply by solving the equation.     

Gelation Mechanism of Soybean 11S Globulin: Formation of Soluble Aggregates as Transient Intermediates

Thermal association-dissociation behavior of soybean 11S globulin was investigated by sucrose density gradient centrifugation and polyacrylamide gel electrophoresis. Soluble aggregates with a molecular weight of 8 × 10⁶ were formed when 0.5% and 5% protein solutions were heated for 1 min at 100°C. At the lower protein concentration, subsequent heating caused disappearance of the soluble aggregate followed by complete dissociation into acidic and basic subunits. At the higher concentration, however, subsequent heating caused formation of highly polymerized aggregates, and gel was formed after 5 min of heating. The soluble aggregates appear to be transient intermediates in the course of gel formation of 11S globulin.     

配煤对降低高灰熔融性煤的三元相图分析

采用2种低灰熔融性温度煤对一种高灰熔融性温度煤进行配煤降低煤灰熔融性温度的研究。依据相平衡理论分析了配煤降低高灰熔融性温度煤的熔融特性。研究表明:配煤可以有效的降低高灰熔融性温度煤的灰熔融性温度,其灰熔融性温度变化并不与配煤比例成线性关系,而与相应的三元相图液相线温度具有很好的相似性,三元相图同样适用于混煤灰的熔融特性研究。在相图的三元低温共晶点和二元共晶线附近灰的熔融温度随灰成分的变化比较显著,且低于周围灰成分的灰熔融性温度,相图理论可以很好的对配煤降低高灰熔融性温度煤的灰熔融性温度进行理论分析。     

Deformation behaviors of magnesium alloy AZ31 sheet in cold deep drawing

To investigate how the popular magnesium alloy AZ31 sheet （aluminum 3%, zinc 1%） behaves in cold working, deep drawing experiments at room temperature, along with finite element（FE） simulation, were performed on the cold forming sheet of the AZ31 alloy after being annealed under various conditions. The activities were focused on the fracture pattern, limit drawing ratio（LDR）, deformation load, thickness distribution, anisotropic effect, as well as the influences of the annealing conditions and tool configuration on them. The results display that punch shoulder radius instead of die clearance, has much influence on the thickness distribution. The anisotropy is remarkable in cold working, which adversely impacts the LDR. The fracture often happens on the side wall at an angle to axis of the deformed specimen. The results also imply that the LDR for the material under present experimental conditions is 1.72, and annealing the material at 450 ℃ for 1 h may be preferable for the cold deep drawing.     

Observation by TEM of spontaneous alloying in nanometre-sized atom clusters in the Au-Al system

Cluster-size dependence of alloying behaviour in nanometre-sized atom clusters has been studied by transmission electron microscopy, using clusters in the Au-Al system, which forms several intermetallic compounds in the phase diagram. In gold clusters of approximately 6–12 nm mean size, rapid dissolution of aluminium atoms took place and Au₂Al or AuAl₂ clusters were formed. When the size of gold clusters was increased to approximately 40 nm, no such rapid spontaneous alloying occurred. These observations suggest that there exists a critical size of initial gold clusters below which aluminide clusters are successfully formed by spontaneous alloying.     

Analysis of bonding state in pure and gold-implanted amorphous SiC by a combination of UHVEM and AES

Single crystalline α-SiC films and Au(target metal)/α-SiC(substrate) bilayer films were irradiated with 2-MeV electrons in an ultrahigh-voltage electron microscope (UHVEM) to form, in situ, pure amorphous SiC (a-SiC) and gold-implanted a-SiC. respectively. In the latter case, sample films were set so that the electron beam was incident on the gold layer. Differences in the bonding state between pure a-SiC and gold-implanted a-SiC were studied by Auger valence electron spectroscopy (AES). In pure a-SiC. the carbon valence state was markedly different from that of α-SiC but the silicon valence state was similar to that of α-SiC. In gold-implanted α-SiC. both the carbon and the silicon valence states were different from those of α-SiC. It is suggested that a high density of molecularized carbon clusters are formed in the amorphous matrix in gold-enriched a-SiC.     

An Electricity Price Forecasting Model with Fuzzy Clustering Preconditioned ANN

In this paper, a hybrid model of fuzzy clustering and ANN (Artificial Neural Network) is proposed for electricity price forecasting. Due to the complicated behavior of electricity price in power markets, market players are interested in maximizing profits while minimizing risks. As a result, more accurate models are required to deal with electricity price forecasting. This paper proposes a new method that makes use of fuzzy clustering preconditioned GRBFN (Generalized Radial Basis Function Network) to provide more accurate predicted prices. Fuzzy clustering plays a key role to prevent the number of learning data from decreasing at each cluster. GRBFN is one of efficient ANNs to approximate nonlinear systems. Furthermore, a modified GRBFN model is developed to improve the performance of GRBFN with the use of DA (Deterministic Annealing) clustering for the parameters initialization and EPSO (Evolutionary Particle Swarm Optimization) for optimizing the parameters of GRBFN. The proposed method is successfully applied to real data of ISO New England, USA.     

Window functions obtained by convolution integrals of rectangular windows

The rectangular, triangular, and Parzen windows, which have been defined independently of each other, are obtained by repeating convolution integrals of the rectangular window with itself. They are extended to make a series of window functions. This series has the advantage that the sidelobe fall-off is variable though it has the disadvantage that the mainlobe band-width for the same highest sidelobe level is 1–1·3 times those of the gaussian, Kaiser, Dolph–Chebyshev or Blackman–Harris windows. Moreover, this series has a desirable mainlobe bandwidth of 0·85–1 times that of cos^x x windows for the same highest sidelobe level and sidelobe fall-off. Thus, this series is useful in designing window functions whose mainlobe bandwidth is in between that of the gaussian or Kaiser windows and that of cos^x x windows and whose sidelobe fall-off is as good as that of the cos^x x windows.