南宁市推广非晶合金变压器初探

我国输配电损耗占电力产量的比重高达7％,降低变压器损耗是我国电力节能工作的一项重要任务。对非晶合金变压器的节能潜力进行了分析。通过对南宁市六区六县变压器的使用情况调查,采用理论分析法和动态投资比较分析方法进行了节能诊断,为政府大面积推广非晶合金变压器提供了决策依据。     

Correlation of increased antioxidation with the phenolic compound and amino acids contents of Camellia sinensis leaf extracts following ultra high pressure extraction

Antioxidants are indispensable for protecting skin cell membranes against oxidative injury caused by reactive oxygen species and other free radicals. Likewise, phenolic compounds are also important barriers to such oxidative injury. In this study, we examined the correlation between increased antioxidation and the contents of phenolic compounds and amino acids in Camellia sinensis leaf extracts obtained by ultra-high pressure extraction. Compared with extracts obtained by leaching and ultrasonic extraction, to evaluate whether this method can improve the pharmacologic effects of C. sinensis leaves. The ultra-high pressure (50 and 100 MPa) extracts had tremendous enhancement of their extraction yield, 1,1-diphenyl-2-picrylhydrazyl (free radical)-scavenging activity and superoxide anion radical scavenging activity, as well as the total phenolic, amino acid, and caffeine contents. The antioxidative effects were promoted not only by the phenolic compounds contents but also by other factors such as the amino acids content in the C. sinensis leaf extracts. These effects showed pressure-dependent increase with the enhanced phenolic compound and amino acid contents of the ultra high pressure extracts. Taken together, ultra high pressure extraction is a potentially useful method for the pharmaceutical, cosmetic, and food industries, because it improves the antioxidative effects of C. sinensis leaves.     

Physical properties of metal-doped zinc oxide films for surface acoustic wave application

Metal-doped ZnO [MZO] thin films show changes of the following properties by a dopant. First, group III element (Al, In, Ga)-doped ZnO thin films have a high conductivity having an n-type semiconductor characteristic. Second, group I element (Li, Na, K)-doped ZnO thin films have high resistivity due to a dopant that accepts a carrier. The metal-doped ZnO (M = Li, Ag) films were prepared by radio frequency magnetron sputtering on glass substrates with the MZO targets. We investigated on the optical and electrical properties of the as-sputtered MZO films as dependences on the doping contents in the targets. All the MZO films had shown a preferred orientation in the [002] direction. As the quantity and the variety of metal dopants were changed, the crystallinity and the transmittance, as well as optical band gap were changed. The electrical resistivity was also changed with changing metal doping amounts and kinds of dopants. An epitaxial Li-doped ZnO film has a high resistivity and very smooth surface; it will have the most optimum conditions which can be used for the piezoelectric devices.     

Hafnium metallocene compounds used as cathode interfacial layers for enhanced electron transfer in organic solar cells

We have used hafnium metallocene compounds as cathode interfacial layers for organic solar cells [OSCs]. A metallocene compound consists of a transition metal and two cyclopentadienyl ligands coordinated in a sandwich structure. For the fabrication of the OSCs, poly[3,4-ethylenedioxythiophene]:poly(styrene sulfonate), poly(3-hexylthiophene-2,5-diyl) + [6, 6]-phenyl C₆₁ butyric acid methyl ester, bis-(ethylcyclopentadienyl)hafnium(IV) dichloride, and aluminum were deposited as a hole transport layer, an active layer, a cathode interfacial layer, and a cathode, respectively. The hafnium metallocene compound cathode interfacial layer improved the performance of OSCs compared to that of OSCs without the interfacial layer. The current density-voltage characteristics of OSCs with an interfacial layer thickness of 0.7 nm and of those without an interfacial layer showed power conversion efficiency [PCE] values of 2.96% and 2.34%, respectively, under an illumination condition of 100 mW/cm² (AM 1.5). It is thought that a cathode interfacial layer of an appropriate thickness enhances the electron transfer between the active layer and the cathode, and thus increases the PCE of the OSCs.     

离心铸造LGJW20钢结硬质合金热疲性能研究

在自约束型热疲劳试验机上对LGJW20钢结硬质合金进行了热疲劳试验,借助金相分析、扫描电镜(SEM)、能谱分析(EDS)等方法观察了合金的显微组织,重点研究了LGJW20的热疲劳性能表现,分析了热处理工艺对合金热疲劳性能的影响。结果表明:合金中硬质相主要由鱼骨状共晶碳化物、网状二次碳化物及大块状碳化物组成;合金的热疲劳裂纹在缺口根部萌生,以一条主裂纹形式沿碳化物扩展;合适的热处理工艺能提高基体的高温屈服强度,改善合金的组织结构,提高了合金的热疲劳性能。LGJW20经过980℃淬火、200℃回火处理后热疲劳性能最佳。     

Health locus of control in late life: A study of genetic and environmental influences in twins aged 80 years and older.

The factor structure of health locus of control (Form A; K. A. Wallston, B. S. Wallston, & R. DeVellis, 1978) was examined in 420 octogenarians (M age?=?83.2 years), and the contributions of genetic and environmental factors to health-control beliefs in 141 octogenarian twin pairs (71 identical, 70 same-sex fraternal) were estimated. Factor analyses reproduced previously proposed factors (Internal, Chance, and Powerful Others). Associations between health-control beliefs and life satisfaction, depression, and other health-related measures (e.g., self-rated health, outpatient contacts, and hospitalization), were modest. Quantitative genetic analyses revealed significant shared environmental influence on the Chance subscale, and significant familiarity (attributable to a combination of genetic and shared environmental influences) on the Powerful Others subscale; there was no evidence of familiarity on the Internal subscale. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Algorithm for wavelet transform of Toeplitz matrices

An algorithm is presented for calculating the 2D wavelet transform of a Toeplitz matrix. The algorithm exploits the special form of the Toeplitz matrix in order to reduce the number of operations required. More specifically. It is shown that the number of 1D wavelet transformations that are necessary to carry out a sub-band decomposition can be reduced to eight     

An architecture of scalable ATM switching system and its performance

In this paper, we present the basic idea and some concepts for the architecture of the ATM switching system being developed in ETRI of KOREA, and also describe its performance. RSE (Reference Service Entity) concept is introduced to define the characteristics of user’s traffic. This concept is useful to represent the demand of CPE (Customer Premise Equipment) user sets and one of point‐to‐multipoint connections. We also propose RUCA (Reference Units for Connection Attempts) concept with which we can illustrate the call/connection level performance of the ATM switching system. This concept can be applied for measuring the call processing capability in both point‐to‐multipoint connections and multipoint‐to‐multipoint connections when call set‐up between users is performed by a sequence of point‐to‐point connections basis. From the basic concepts and the recommendations of ITU‐T, the design objective of the system performance is specified. We represent the methodologies for dimensioning the system to achieve the design objectives, and estimate the system performances. Then we show that our developing system has suitable performance to accommodate the future B‐ISDN. This revised version was published online in August 2006 with corrections to the Cover Date.