On the local behavior of spaces of range image patches

We focus on the quantitative and local topological properties of range images. We consider the spaces M_m of m × m high-contrast patches of range images for m=?3, 5, 7, 9, 11. Using computational topological tools to analyze range image patches, we detect that M₃ (M₉, M₁₁) has core subsets with the topology of a circle, M₃, M₅, M₇, M₉ and that M₁₁ have some subspaces with the topology of a Klein bottle. We also discover that the largest subspace with the Klein bottle’s topology decreases as the measurements of patches increase, which generalizes the results in the paper of H. Adams and G. Carlsson, and demonstrates properties among optical images and range image patches, which are more similar than those established by Lee et al.

     

陕北风沙滩区浅层地下水环境演化和发展趋势

陕北风沙滩区生态脆弱,但在风沙滩区及周边人类大量的活动,使该区域地下水环境发生了很大变化.利用风沙滩区浅层长系列地下水观测数据,结合区域水文地质条件,从内外动力地质和人为活动共同作用来分析浅层地下水赋存空间环境演化规律,预测发展趋势.完成了对浅层地下水环境多角度多层次演化的分析,并从风沙滩区植被、降落漏斗、海子面积、水质等多方面进行了发展趋势预测.得出陕北风沙滩区浅层地下水环境在人为破坏和人为保护双向发力下,向相反的方向演化,并表现出时好时坏.总之在人为破坏没有停止之前,人为保护虽有作用,但不治本.     

属性证书的管理与应用

公钥基础设施PKI很好地解决了身份认证问题,但是无法满足权限管理问题,而属性证书(Attribute Certificate)提供了全新的方法来解决细粒化访问控制问题,将PKI框架扩展到了授权领域。本文就当前有关属性证书的标准和相关文献,针对其技术概貌作了一些综述,并介绍了属性证书的应用。     

Diamino telechelic polybutadienes for solventless styrene-butadiene-styrene (SBS) triblock copolymer formation

High molecular weight, high functionality diamino telechelic polybutadienes (TPBs) were synthesized by ring-opening metathesis polymerization (ROMP) of 1,5-cyclooctadiene (COD) in the presence of a chain transfer agent, 1,8-dicyano-4-octene, followed by lithium aluminum hydride reduction. Melt coupling of diamino TPB with anhydride-terminated polystyrene (PS-anh) resulted in the formation of styrene-butadiene-styrene (SBS) triblock copolymers; ca. 80% maximum conversion of PS-anh was achieved within 30 s. The results from SAXS, TEM, and rheological measurements of the coupling products confirmed the formation of SBS triblock copolymers having lamellar morphology. A fluorescent-labeled PS-anh was used to study the coupling kinetics by diluting the reactants by the addition of non-functional PS.     

精密数显转台研制

光电传感和精密刻划技术 ,是开发精密数显转台的主要技术基础。本文详细介绍基本原理、结构要求、功能特点、工艺试验和精度测试等。样机系列表明 ,其精度和性能基本达到和部分指标超过 (国家 )部颁一级精度的标准。     

A self-learning particle swarm optimizer for global optimization problems

Particle swarm optimization (PSO) has been shown as an effective tool for solving global optimization problems. So far, most PSO algorithms use a single learning pattern for all particles, which means that all particles in a swarm use the same strategy. This monotonic learning pattern may cause the lack of intelligence for a particular particle, which makes it unable to deal with different complex situations. This paper presents a novel algorithm, called self-learning particle swarm optimizer (SLPSO), for global optimization problems. In SLPSO, each particle has a set of four strategies to cope with different situations in the search space. The cooperation of the four strategies is implemented by an adaptive learning framework at the individual level, which can enable a particle to choose the optimal strategy according to its own local fitness landscape. The experimental study on a set of 45 test functions and two real-world problems show that SLPSO has a superior performance in comparison with several other peer algorithms.     

我国不锈钢管市场需求及国内外不锈钢管生产技术发展趋势

介绍了我国不锈钢管市场需求和预测分析,国外不锈钢管生产技术发展趋势。论述了我国不锈钢管生产存在的问题及与世界先进水平的差距。提出了我国不锈钢管技术改造的建议。     

微波介质陶瓷的界面特性及其对介电性能的影响

详细地总结了界面的偏析、扩散和润湿性对微波介电性能的影响机理。并评述了粉末的初始状态、烧结工艺、添加剂(掺杂)和烧结方法等因素对材料界面特性的影响，进而影响到材料介电性能的研究进展。最后指出了在微波介质陶瓷界面研究领域面临的问题及今后的发展方向。     

复合固体超强酸SO42-/ZrO2-TiO2催化合成三醋酸甘油酯

采用复合固体超强酸SO₄^2-/ZrO₂-TiO₂为催化剂，甘油和冰醋酸为原料，结合醋酸精馏回流工艺，合成了三醋酸甘油酯（TCG）。通过对合成工艺改进，免除了有毒带水剂的使用。使TCG合成更安全，更经济和环保。催化剂制备和TCG合成最佳工艺条件为：硫酸浸渍液浓度（0.5～0.55） mol·L^－1，焙烧温度（550～600） ℃，催化剂用量（占总投料量质量分数）2.5％～3.0%。投料比n（甘油）∶n（醋酸）=1∶ 5.5，反应温度130 ℃，反应时间3.0 h，产品收率达92.6%，催化剂可重复使用6次，易于再生。     

Effect of Cr3C2 on Valence-Electron Structure and Plasticity of Rim Phase in Ti(C,N)-Based Cermets

Based on the empirical electron theory of solids and molecules, the valence-electron structure (VES) of the rim phase in Ti(C,N)-based cermets was calculated, and the relationship between the VES and plasticity was determined. The results indicated that the plasticity of the rim phase in a Ti(C,N)-based cermet could be defined using the sum of the n _a values for the covalent bonds, and that chromium dissolution in the rim phase improved the plasticity of the rim phase. Moreover, a series of experiments showed that adding Cr₂C₃ to a typical Ti(C,N)-based cermet strengthened the interface. Based on those results, a Ti(C,N)-based cermet with added Cr₃C₂ was manufactured; the new cermet had more than twice the transverse rupture strength of a typical cermet.