Design for 2-D error feedback networks with identical coefficient sets

In realization of recursive digital filters with fixed point arithmetic, an error caused by roundoff arises. It is known that the level of the roundoff noise of an IIR filter tends to be high when the poles are close to the unit circle. Error feedback (EF) is an effective method to reduce the roundoff noise. It is desirable to design an EF network using as few parameters as possible in order to keep computational costs low. In this paper, we propose a method for designing a 2D EF network with identical coefficient sets. That is, the EF coefficients are divided into several subsets such that all the elements within each set have the same absolute value. In order to optimize the coefficient sets, we propose an algorithm by using the genetic algorithm. In the numerical example, we demonstrate the effectiveness of the proposed method.     

Marginal adaptation of resin-bonded light-cured glass ionomers in dentin cavities

PURPOSE: To investigate the marginal adaptation of resin-modified glass ionomer cements in dentin cavities placed with or without additional application of resin bonding systems. MATERIALS AND METHODS: Three resin-modified materials (Fuji II LC, Photac-Fil, Vitremer), one compomer (Dyract) and as reference an adhesively bonded resin composite system (Gluma CPS-Pekafill) were used. Flat peripheral dentin surfaces on human molar teeth were produced by wet grinding on SiC paper. Cylindrical cavities, 3.5 mm wide, were prepared in these dentin areas and restored with the individual materials. Sixty cavities were pretreated and restored as requested by the respective manufacturers. Following water storage of the specimens for 15 minutes or 24 hours, excess was gently removed by wet grinding for microscopic inspection of the marginal area. Additionally, in 30 cavities an experimental one-component adhesive resin system, a proprietary dimethacrylate and HEMA mixture dissolved in acetone, was combined with each of the restoratives for evaluation after 15-minutes water storage. Finally, in six cavities each, Dyract was combined with Prime and Bond 2.0, and Vitremer with Scotchbond Multi-Purpose Plus for assessment after 15 minutes. Maximum marginal gap widths (MGW) were measured. One-way ANOVA by ranks (Kruskal-Wallis-Test) followed by Wilcoxon's Two-Sample test were used to study the statistical difference of MGW among the treatment groups at a rejection level P = 0.05. RESULTS: Neither the conventionally placed material systems nor the restorations in combination with adhesives showed consistently gap-free margins after 15-minute water storage. After 24-hour storage with Vitremer 4 of the 6 restorations were gap-free, whereas with all other materials only perfect margins were registered. There was, however, no significant difference between the groups. Application of the experimental and/or the specific resin bonding agents had no effect on early MGW except for the Photac-Fil group, which was significantly reduced.     

爱知县淑德大学8号楼

在有较大高差台地的校园园区内排列鳞次栉比的校舍,建筑物之间诸多大小不等的室外围合空间是整个校园空间的主要特征。将教室、食堂之间的空间为活泼好动的学生营造成最具活力的“舞台”,在这个“舞台”上由室内外一体化的缓坡、大台阶、廊桥等各要素从一层到三层构成连续的断面,不管哪一层的人们都能感受到其他各层活动的情况,是充满“动感”的空间。建筑物宽18m,长92m,形状非常细长,横向由6m和12m两种柱距组成,长向由4m的柱距均分构成连续的架构,这个模数使不同用途和大小的空间(24～336m2)都能获得良好的开间一进深比例,4m跨度的构架单元…     

A mathematical model for the solute drag effect on recrystallization

The model for the solute drag effect in phase transformations has been applied to recrystallization, i.e., moving grain boundaries. In this model, the total driving force is dissipated by the interfacial energy, the finite interfacial mobility, the solute drag in boundaries, and diffusion in the matrix ahead of the interface, of which all are taken into account consistently. The effects of the Gibbs energy of segregation and the diffusivity of impurity atoms in boundaries were investigated. The results show that the Gibbs energy of segregation mainly affects the critical composition at which the drastic change in the boundary velocity appears, and the diffusivity of impurity atoms in boundaries mainly affects the velocity reduced by the solute drag effect. In other words, the Gibbs energy of segregation and the diffusivity of impurity atoms in boundaries can be evaluated from experimental data by means of the present model. This model was applied to the Al−Mg system, and the Gibbs energy of segregation and the diffusivity of Mg in boundaries were evaluated from experimental data. The evaluated Gibbs energy of segregation agrees with the estimate based on elastic energy considerations. The diffusivity estimated from this model is smaller than that measured along the grain boundary. ZI-KUI LIU, formerly with the Department of Materials Science and Engineering, Royal Institute of Technology     

Effect of clenbuterol on sulfur dioxide-induced acute bronchitis in guinea pigs

When guinea pigs were exposed to sulfur dioxide (SO2) gas (800 ppm, 2 h), they showed hyperresponsiveness to intravenously administered serotonin (5-hydroxytryptamine (5-HT)). This hyperresponsiveness continued for over 24 h after the exposure to the gas. The degeneration, desquamation of epithelium, and edema of the lamina propria of the trachea and bronchi were observed in animals after a 2-h exposure of SO2 histopathologically. These changes seemed to be the early phase of acute bronchitis. Then, we examined the effect of clenbuterol, a selective beta-2 adrenoceptor agonist, on the SO2-induced bronchial hyperresponsiveness in these animals. Orally administered clenbuterol (1-10 micrograms/kg) suppressed the hyperresponsiveness to 5-HT in a dose-dependent manner. These results suggest that clenbuterol might inhibit the hyperresponsiveness that accompanies acute bronchitis and that this agent may be useful for remission of broncho-spasm.     

Unilateral labyrinthectomy downregulates glutamate receptor delta-2 expression in the rat vestibulocerebellum

Subcortical damage in neonates often has more severe consequences than in adults. Unilateral electrolytic hippocampal lesions in adult rats typically result in transient memory deficits, whereas neonatal lesions cause lasting memory impairments. We hypothesized that unilateral lesions made at birth may affect synaptic physiology in the contralateral hippocampus. Consequently, the ability to sustain long-term potentiation (LTP), a form of synaptic plasticity believed to underlie certain forms of memory, was compared between slices from the remaining hippocampus of rats lesioned as newborns and as adults. Initial studies showed that a train of 10 stimulation bursts patterned after the hippocampal theta rhythm produced robust and stable LTP both in slices from controls and rats lesioned at birth. However, a theta burst pattern of stimulation closer to intrinsic physiology (five burst pairs separated by 30 s each), induced significantly less LTP in slices from rats lesioned at birth compared to those from controls and rats lesioned as adults. To investigate possible mechanisms underlying the deficit, the degree of paired-pulse facilitation (PPF) as well as the amount of depolarization occurring between two successive theta bursts were analyzed. The lesion did not detectably change PPF characteristics, suggesting that presynaptic mechanisms are normal. However, the extent to which a burst response was increased by a prior burst was significantly diminished in slices from rats lesioned at birth compared to those from controls and rats lesioned as adults, indicating that postsynaptic factors involved in the initial triggering events of LTP are affected by the lesion. Reduced ability to sustain LTP in the remaining hippocampus may contribute to impaired memory function after unilateral neonatal hippocampal lesion.     

爱知县淑德大学9号楼

这座建筑是大学的语言教育中心,设有500台计算机、影像和音响系统,主要用于语言教学、留学生教学及国际交流活动。作为建筑“外皮”的性能,设计满足以下三点要求:①充分考虑减少计算机显示器的光反射,营造照度对比小的均质柔和的光环境。②在影像放映时,光环境可渐变调节。③适度的外墙散热功能。教室分别布置在南北两侧,南面的波纹玻璃和合成树脂板材形成双层表皮,中间设计有可调控百叶,能根据日照的入射角度调节;夏季可排热,冬季则可让阳光照射进室内,从而既可获得柔和均质的采光效果又可对热负载进行有效的控制。在建筑北侧满铺的玻璃砖…     

Structural analysis of β-form poly(p-xylyene) starting from a high-resolution image

The crystal structure of β-form poly(p-xylylene) is analysed starting from a high-resolution image of a single crystal of this polymer. The high-resolution image corresponding to the projection of molecules onto the ab-plane along the chain axis shows clearly the mutual position of each molecule in a unit cell. The molecules are aligned wavily in the direction along the a-axis and the rough positions of their centres in a unit cell can be determined from the image. The refinement of the structure is carried out by the usual least-squares method using the intensities of electron and X-ray diffractions. The space group of the β-form is trigonal, P3, and the lattice dimensions are a=2.052 nm, c=0.655 nm and γ=120°. The unit cell contains 16 molecules and one of them is considered to occupy statistically one of three equivalent orientations so as to satisfy the P3 symmetry.