Study on the reduction behavior of CoOOH during the storage of nickel/metal-hydride battery

The storage of nickel/metal-hydride (Ni-MH) battery with co-precipitated cobalt hydroxide and post-added cobalt compound as the additives for pasted Ni(OH)₂ electrode is studied in this paper by using galvanostatic charge–discharge, cyclic voltammetry and X-ray diffraction (XRD). It is shown that (I) capacity loss occurs only on the battery with post-added cobalt compound during the storage; (II) CoOOH derived from co-precipitated cobalt hydroxide has a better stability than the one from post-added cobalt compound and an irreversible reduction of the latter is observed; and (III) an inactive Co + 3O(OH) is obtained from Ni(OH)₂ electrode with post-added cobalt compound after the storage and should be responsible for the property deterioration of Ni-MH battery. Thus, it is important to increase the stability of CoOOH derived from post-added cobalt compound when Ni-MH battery suffers a long-term storage.     

基于局部线性投影的三维旋转人脸识别

本文在基于三维形态学模型的人脸识别研究中,运用局部线性投影算法(ProjectiveLLE,PLLE)取代了普遍使用的经典降维方法PCA,在高维空间中减小了降维过程中的线性失真。有效提高了所构建的三维形态学模型的质量,经实验证明该算法对于提高拟合的精度和大角度旋转人脸的识别率都取得了比较理想的效果。     

Analysis and Reduction of Ultrasonic Pitting Defects on Hard Disk Surfaces

It has become of paramount importance to be able to perform failure analysis of defects on hard disk surfaces quickly and accurately. In this study, ultrasonic pitting defects on hard disk surfaces were investigated. A new electrical tagging pattern system, which directly translated the channel bits to magnetic transitions during writing of the magnetic pattern around a defect, was used in the failure analysis of magnetic recording disks to mark defective sectors. With the help of the Kerr magneto-effect, the defective sectors were effectively located for further failure analysis. Results of the failure analysis revealed that there was 30% to 40% loss of the recorded magnetic bit signal due to an increase in the gap between a recording head and a hard disk surface with ultrasonic pitting defects. The experiments performed indicated that low ultrasonic power for disk cleaning could reduce the ultrasonic pitting defects significantly. The maximum failure rate due to single-type ultrasonic pitting defects was reduced from 33.4% to 16.7%, while the maximum failure rate due to cluster-type ultrasonic pitting defects was reduced from 11.1% to 5%.     

A bandwidth latency tradeoff for broadcast and reduction

The “fractional tree” algorithm for broadcasting and reduction is introduced. Its communication pattern interpolates between two well known patterns—sequential pipeline and pipelined binary tree. The speedup over the best of these simple methods can approach two for large systems and messages of intermediate size. For networks which are not very densely connected the new algorithm seems to be the best known method for the important case that each processor has only a single (possibly bidirectional) channel into the communication network.     

一种基于Rough集的属性值约简算法

文章将Rough集理论应用于不同类型的决策表(一致决策表和不一致决策表)的约简,给出了广义决策、决策规则的一致程度、属性值重要性等定义,在此基础上提出了一种基于Rough集的属性值约简算法。该算法不仅能得到更为简洁的决策规则,而且能保持决策规则的一致程度不变。实例分析表明该算法是可行的。     

知识表达系统函数规则简化的理论基础

0 引言粗集理论是波兰的Z.Pawlak等一批科学家提出来的,被用来研究不完整数据、不精确知识的表达、学习、归纳等。有些学者认为它无论在理论和应用上都是一种新的、最重要的并且是迅速发展的研充领域,为机器学习、知识获取、决策分析、数据库知识发现、专家系统、决策支持系统、归纳推理、模式识别、模糊控制等提供了一种很有效的数学方法。我们的研     

Fe1—xO基氨合成催化剂还原性能的研究

具有维氏体（Ｗｕｓｔｉｔｅ）相结构的Ｆｅ１－ｘＯ基催化剂低温还原性能明显优于传统的Ｆｅ３Ｏ４基催化剂，其还原诱导期短。在干气氛条件下，Ｆｅ１－ｘＯ基催化剂还原动力学可用“壳－核模型”描述。空速和温度明显影响Ｆｅ１－ｘＯ基催化剂的活化，而压力影响不如它们显著。在工业还原过程中宜采用“低温、低压、高空速、高氢”的操作原则     

Are major economies on track to achieve their pledges for 2020? An assessment of domestic climate and energy policies

Many of the major greenhouse gas emitting countries have planned and/or implemented domestic mitigation policies, such as carbon taxes, feed-in tariffs, or standards. This study analyses whether the most effective national climate and energy policies are sufficient to stay on track for meeting the emission reduction proposals (pledges) that countries made for 2020. The analysis shows that domestic policies of India, China and Russia are projected to lead to lower emission levels than the pledged levels. Australia's and the EU's nationally legally binding policy framework is likely to deliver their unconditional pledges, but not the conditional ones. The situation is rather unclear for Japan, South Korea, Brazil and Indonesia. We project that policies of Canada and the USA will reduce 2020 emission levels, but additional policies are probably needed to deliver their pledges in full. The analysis also shows that countries are implementing policies or targets in various areas to a varying degree: all major countries have set renewable energy targets; many have recently implemented efficiency standards for cars, and new emission trading systems are emerging.     

One-photon processes of latent image formation in silver halides

Abstract

A new one-photon process for latent image formation in silver halides is proposed. The model is an extension of the theoretical concepts of Gurney-Mott, Hamilton and Lowe. Hamilton proposed a four-photon mechanism for the photochemical formation of Ag₄ latent image centres. Subsequently, Lowe developed a two-photon mechanism, which includes hole trapping by Ag₂ reduction centres. Mitchell proposed a two-photon mechanism based on the presence of electron trapping Ag₂ centres that act as sublatent image centres. One-photon latent image formation was proposed which relied on gold-containing electron-trapping centres; however, these mechanisms were considered to be fogging mechanisms. From the concepts of the previous mechanisms, a one-photon latent image mechanism is proposed that does not result in fog. This one-photon process is based on the presence of both electron and hole-trapping Ag₂ centres on the same crystal before exposure. Both photoelectron and photohole, which arc formed by light absorption, participate in this mechanism. The required electron-hole energy separation is estimated to be about 1.4 eV and is thus well above the thermal energy at room temperature (about 0.03 eV). Experimental evidence for one-photon processes in silver halide systems supports the proposed one-photon mechanism for Ag₄ latent image formation.     

Solving separable elliptic equations by the block stride reduction algorithm

A comparison of the Buneman version of the block cyclic reduction (BCR) algorithm and Stride Reduction (BSR) based on polynomial factorization for separable elliptic equations with Dirichlet boundary conditions is presented. This study was initiated by an interest in the parallel computing techniques that can be used to increase the computational efficiency of these model problems