Effects of calcium,samarium addition on microstructure and mechanical properties of AZ61 magnesium alloy

The microstructure and mechanical properties of AZ61 magnesium alloy with Ca, Sm addition were investigated. The results showed that the addition of 0.5 wt.% Ca reduced the quantity of Mg17Al12 phase, and formed a new Al4 Ca phase which is reticular in AZ61 alloy. With the addition of Ca and Sm, the microstructure was further refined and new Al-Sm rich phases were formed in AZ61 alloy with 0.6 wt.%–1.5 wt.% Sm addition, the TEM analysis confirmed that they were Al2 Sm and Al4 Sm. Tensile tests showed that 1.0 wt.% Sm addition contributed to the formation of the Al2 Sm and Al4 Sm and the improvement in the ambient strength, i.e., an ultimate tensile strength of 327 MPa and an elongation of 10.1%. However, excessive Sm addition led to the coarsening of Al2 Sm and Al4 Sm phases, thus resulted in the decline of strength and plasticity.     

AZ31与AZ61异种镁合金的TIG焊研究

采用TIG焊对AZ31与AZ61镁合金薄板进行连接,分别采用了AZ31和AZ61焊丝,比较焊接效果的影响.通过显微镜、扫描电镜、X-ray物相检测等实验方法,分析了两种焊丝焊接接头的外观形貌、显微组织、焊缝析出相及力学性能等差异.研究结果表明:采用AZ31和AZ61两种焊丝都能完成AZ31与AZ61镁合金薄板的对焊,获...     

Flexible solar cells based on PCBM/P3HT heterojunction

[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) / poly (3-hexylthiophene) (P3HT) heterojunction has not only the absorption in ultraviolet light for PCBM,but also the absorption in visible light for P3HT, which widens the incident light harvest range, improving the photoelectrical response of hybrid solar cell effectively.Using conducting polymers blend heterojunetion consisting of C60 derivatives PCBM and P3HT as charge carrier transferring medium to replace I3-/I- redox electrolyte and dye, a novel flexible solar cell was fabricated in this study.The influence of PCBM/P3HT mass ratio on the photovoltaic performance of the solar cell was also studied.flexible solar cell achieved a light-to-electric energy conversion efficiency of 1.04%, an open circuit voltage fill factor (FF) of 0.46.     

基于轻量级IPv6的互联互通原型系统分析与设计简

异构网络互联互通技术是物联网关键技术之一,主要是为了将有线网络与无线网络技术有效的集成,实现透明的无缝连接,IP网络架构因其可扩展性、通用性、具备成熟的基础设施等优势成为当前物联网异构网互通合的研究热点。本文提出了将61owpan技术应用于异构网络,从而设计出一套基于轻量级IPv6技术的跨网络互联互通系统。系统可实现61owpan节点通过一个运行61owpan协议和标准ip协议的网关与一台运行标准ip协议的远程Pc机进行通信。     

A new view of fuzzy hypernear-rings

In this survey article, we first introduce the concept of quasi-coincidence of a fuzzy interval value with an interval valued fuzzy set. This concept is a generalized concept of quasi-coincidence of a fuzzy point within a fuzzy set. By using this new idea, we consider the interval valued (∈,∈∨q)-fuzzy sub-hypernear-rings (hyperideals) of a hypernear-ring, and hence, a generalization of a fuzzy sub-near-ring (ideal) is given. Some related properties of fuzzy hypernear-rings are described. Finally, we consider the concept of implication-based interval valued fuzzy sub-hypernear-rings (hyperideals) in a hypernear-ring, in particular, the implication operators in Lukasiewicz system of continuous-valued logic are discussed.     

Discounted least squares-improved circular back-propogation neural networks with applications in time series prediction

Summary As a generalization of the multi-layer perceptron (MLP), the circular back-propagation neural network (CBP) possesses better adaptability. An improved version of the CBP (the ICBP) is presented in this paper. Despite having less adjustable weights, the ICBP has better adaptability than the CBP, which quite equals the famous Occams razor principle for model selection. In its application to time series, considering both structural changes and correlations of time series itself, we introduce the principle of the discounted least squares (DLS) in CBP and ICBP, respectively, and investigate their predicting capacity further. Introduction of DLS improves the predicting performance of both on a benchmark time series data set. Finally, the comparison of experimental results shows that ICBP with DLS (DLS-ICBP) has better predicting performance than DLS-CBP.Supported by Natural Science (grant No.BK2002092) and QingLan project foundations of Jiangsu province and Returnee foundation of China.     

Intramolecular Donor–Acceptor Regioregular Poly(3‐hexylthiophene)s Presenting Octylphenanthrenyl‐Imidazole Moieties Exhibit Enhanced Charge Transfer for Heterojunction Solar Cell Applications

Intramolecular donor–acceptor structures prepared by covalently binding conjugated octylphenanthrenyl‐imidazole moieties onto the side chains of regioregular poly(3‐hexylthiophene)s exhibit lowered bandgaps and enhanced electron transfer compared to the parent polymer, e.g., conjugation of 90 mol% octylphenanthrenyl‐imidazole moieties onto poly(3‐hexylthiophene) chains reduces the optical bandgap from 1.91 to 1.80 eV, and the electron transfer probability is at least twice as high as that of pure poly(3‐hexylthiophene) when blended with [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester. The lowered bandgap and the fast charge transfer both contribute to much higher external quantum efficiencies, thus much higher short‐circuit current densities for copolymers presenting octylphenanthrenyl‐imidazole moieties, relative to those of pure poly(3‐hexylthiophene)s. The short‐circuit current density of a device prepared from a copolymer presenting 90 mol% octylphenanthrenyl‐imidazole moieties is 13.7 mA · cm^?2 which is an increase of 65% compared to the 8.3 mA · cm^?2 observable for a device containing pure poly(3‐hexylthiophene). The maximum power conversion efficiency of this particular copolymer is 3.45% which suggest that such copolymers are promising polymeric photovoltaic materials.     

鄂尔多斯盆地胡尖山地区长61致密砂岩储层成岩特征与孔隙度定量恢复

在对大量岩心和薄片分析的基础上,运用扫描电镜、阴极发光、高压压汞等实验手段,系统分析了鄂尔多斯盆地胡尖山地区长6₁储层的成岩作用特征及其对储层物性的影响,并进一步对孔隙演化进行了定量恢复。结果表明：胡尖山地区长6₁储层整体处于中成岩阶段A期,主要经历了压实—压溶、胶结、溶蚀等成岩作用,且不同成岩作用对储层的孔隙发育造成了不同程度的影响。压实作用破坏了大量原生粒间孔,是导致研究区储层致密最主要的因素,孔隙度平均减少了18.41%,孔隙空间损失率达56.62%;胶结作用次之,在堵塞了孔隙空间的同时也一定程度地增强了颗粒的抗压实强度,孔隙度平均降低了10.38%,孔隙空间损失率达19.78%;溶蚀作用使碎屑颗粒及填隙物等不稳定组分溶解而产生大量的次生孔隙,从而改善了储层物性,增加的孔隙度平均为2.26%。根据成岩作用对物性的影响,结合测井响应特征,将该区长6₁致密砂岩储层划分出绿泥石膜剩余粒间孔相、剩余粒间孔相、长石溶蚀相、黏土矿物胶结相、碳酸盐胶结相及压实相等6种成岩相带,绿泥石膜剩余粒间孔相是研究区最有利的油气储集相带,剩余粒间孔相次之。     

ZK61S镁合金微弧氧化膜层的结构及耐腐蚀性能

为了提高ZK61S镁合金的耐腐蚀性能,采用微弧氧化方法以不同电压(300,380,450 V)在ZK61S镁合金表面制备氧化膜并进行封孔处理。利用金相显微镜、扫描电镜、X射线衍射仪分析膜层的形貌、结构和组成;通过腐蚀电位试验、中性盐雾腐蚀试验及抗剥落腐蚀试验进行耐腐蚀性能考核。结果表明:微弧氧化呈现疏松多孔形态且均匀覆盖于基材表面,主要由Mg、MgO和Al_2Si_2O_5(OH)4相组成;微弧氧化处理后试样的腐蚀电位显著提升,且380 V所得微弧氧化试板的腐蚀电位达到-881.53 m V,经过408 h的中性盐雾腐蚀试验后的腐蚀速率为0.012g/(m~2·h),耐蚀性能比未进行表面处理的基材提高了88倍;经封孔处理的微弧氧化试板经过456 h的中性盐雾腐蚀试验后腐蚀速率降低到0.003 g/(m~2·h);封孔处理使微弧氧化膜的抗剥落腐蚀性能由微弧氧化后的EB级提升到EA级。