Estimating the electrical conductivity of cement paste pore solutions from OH, K and Na concentrations

A proposed method for estimating the electrical conductivity of cement paste pore solution at 25 °C is based on the concentrations of OH⁻, K⁺ and Na⁺. The approach uses an equation that is a function of the solution ionic strength, and requires a single coefficient for each ionic species. To test the method, the conductivity of solutions containing mixtures of potassium hydroxide and sodium hydroxide with molar ratios of 4:1, 2:1 and 1:1, and having ionic strengths varying from 0.15 to 2.00 mol/l were measured in the laboratory and compared to predicted values. The proposed equation predicts the conductivity of the solutions to within 8% over the concentration range investigated. By comparison, the dilute electrolyte assumption that conductivity is linearly proportional to concentration is in error by 36% at 1 mol/l and in error by 55% at 2 mol/l. The significance and utility of the proposed equation is discussed in the context of predicting ionic transport in cement-based systems.     

Modeling of batch phenol biodegradation in internal loop airlift bioreactor with gas recirculation by Candida tropicalis

A mathematical model for simulating the dynamic behaviors of batch phenol biodegradation processes in internal loop airlift bioreactor (ILAB) with gas recirculation using free cells of the yeast Candida tropicalis was established by coupling the fluid dynamic model and the mass balance model. Based on the coupling arithmetic, the program for evaluating batch phenol biodegradation processes was achieved. The predicted results of linear liquid velocities, gas holdups, linear gas velocities, cell and phenol concentration profiles in the riser and the downcomer of the ILAB with gas recirculation agreed very well with the corresponding experimental data, and the applicability and reliability of this proposed model were validated.     

基于卷积树核的中文微博情感要素识别

情感要素识别是情感分析的关键子任务之一,其目的是识别出文本情感所作用的情感对象。文本情感要素识别属于最细粒度的情感分析,吸引了大量研究者的关注。中文微博由于其语言简短灵活、文本不规范、噪声较大等特点,给中文微博情感分析研究工作带来了新的挑战。目前大部分情感要素识别方法都是基于规则的方法或者基于扁平化特征的统计学习方法,区分噪声的能力不强,性能提升有限。针对中文微博的特点,提出一种基于卷积树核的情感要素识别算法,即首先对句子进行词性标注与依存关系分析,将句子中的名词作为候选情感要素;然后基于两种不同的修剪策略对依存树进行修剪,以获取每个候选情感要素的结构化信息;最后采用卷积树核计算依存树的相似度,并在此基础上识别句子中的情感要素。NLPCC2012和NLPCC2013中文微博情感分析评测任务中的实验验证了该方法的性能,其准确率相比于传统方法有显著提升。     

覆盖粗糙集的图表示和2-部矩阵

通过图论和矩阵理论研究覆盖粗糙集。首先提出覆盖的关联二部图,一个覆盖的任意两个关联二部图都是同构的,进而从图论的角度给出一类覆盖近似算子的等价描述;然后给出二部图的2-部矩阵的定义,通过一个覆盖的关联二部图的2-部矩阵,既可以判断出这个覆盖是不是一元覆盖,又可以求出这个覆盖中的可约元;最后,研究划分对应的2-部矩阵的特点。     

基于Mexican hat函数的图像特征提取和配准算法

使用Mexican hat函数作为特征检测算子,对图像进行局部区域提取和特征点提取,在此基础上,提出了一种结合局部区域和特征点的图像配准算法。使用Mexican hat检测算子和零交汇点检测的方法获得局部区域特征并进行初步匹配,然后使用基于不同尺度空间的Mexican hat检测算子进行特征点提取。将特征点按照局部区域进行分组,再对每一组内的特征点进行匹配操作。最后使用基于分组的随机采样一致性检验进行变换矩阵求解。算法使用Mexican hat特征检测算子进行两种图像特征的提取,对两种特征分别进行匹配,完成图像配准操作。实验结果表明,给出的Mexican hat特征检测算子在配准精度上不亚于当前主流检测方法,配准算法具有复现率高和运算速度快的优点。     

混合排名映射概率和混沌搜索的ABC算法

针对由于人工蜂群算法(Artificial Bee Colony algorithm,ABC)采用直接映射概率选择食物源而引起收敛速度慢、陷入局部最优等问题,提出一种混合排名映射概率和混沌搜索的人工蜂群算法((Artificial Bee Colony algorithm based on Hybrid rank mapping probability and Chaotic search,ABC-HC))。首先,利用目标函数值的排名来获取选择食物源的排名映射概率,并提出计算排名映射概率的两种方法;然后,在观察蜂阶段,融合这两种计算概率的方法,即不同的搜索阶段采用不同的排名映射方法计算食物源选择概率,构造基于混合排名映射概率的人工蜂群算法,以便能够维持种群的多样性避免陷于局部最优;最后,在侦查蜂阶段,使用混沌搜索替代随机搜索以便进一步提高收敛速度,最终获得较好的全局最优解。对10个标准测试函数进行仿真,结果表明,ABC-HC算法不仅提高了收敛速度,而且更能跳出局部最优,有效地找到全局最优解,优于标准的ABC算法和进化算法。     

室温超快速制备HKUST-1及其对甲苯的吸附性能

以硝酸铜和均苯三甲酸为原料,通过水滑石法室温10 s快速制备了一种金属有机骨架材料HKUST-1,对其进行了XRD、SEM和N_2吸附表征,测定了甲苯在HKUST-1上的吸附等温线、动力学和吸附-脱附循环性能。结果表明,水滑石的添加使HKUST-1可在室温10 s内快速合成,HKUST-1的BET比表面积达到2170.7 m~2/g,总孔容为0.97 cm~3/g。HKUST-1在25℃时对甲苯的饱和吸附量达到6.67 mmol/g,在低相对分压(p/p_0≈0.029)下,HKUST-1对甲苯的吸附量高于其他材料约10倍。经5次吸附-脱附循环后,HKUST-1的甲苯饱和吸附量几乎不变,具有很好的再生性能。     

Diterpene resin acids: Major active principles in tall oil against Variegated cutworm,Peridroma saucia (Lepidoptera: Noctuidae)

Tall oil, a by-product of the kraft process for pulping softwood, has been shown to have insecticidal properties. In the present study, the active principles in tall oil against the variegated cutworm,Peridroma saucia Hübner, were investigated. GC-MS analysis showed that abietic, dehydroabietic, and isopimaric acids were major resin acid components of crude tall oil and depitched tall oil. When crude tall oil samples of differing resin acid composition were incorporated into artificial diet at a concentration of 2.0% fresh weight, they suppressed larval growth by 45–60% compared to controls. This suppression was significantly (P0.05) correlated with the equivalent contents of abietic, dehydroabietic, isopimaric, and total resin acids. These results were also evident from a diet choice test, showing that the second-instar larvae obviously selected diets with low levels of resin acids when different diets were randomly arranged in a Petri dish. Bioassays with pure resin acids (abietic, dehydroabietic, and isopimaric acids) demonstrated that all individual chemicals have similar bioactivity against this insect. Comparison of the bioactivities of depitched tall oil and an equivalent mixture of pure resin acids in thePeridroma chronic growth bioassay indicated that pure resin acids and depitched tall oil share a common mode of action to this insect. This study confirms that resin acids are major active principles in tall oil against the variegated cutworm, but other chemicals likely also contribute to the bioactivity of tall oil.     

过程工程所流化床直接还原技术研究进展

“双碳”背景下，钢铁工业亟待低碳重塑，氢气直接还原(常称为“氢冶金”)是国内外竞相研发的重要方向。流态化直接还原是过程工程所六十多年来一直坚持的研究方向。值此叶渚沛先生诞辰120周年之际，本综述回顾并概述了过程工程所在流态化直接还原基础理论和工业应用两方面所取得的一系列重要成果。基础理论方面包括颗粒间黏着力与分离力相互竞争黏结机制、聚团流化和慢速失流的发现、不同铁形貌析出机理和黏结特性，以及降低颗粒间黏结力(颗粒包覆改性、调控铁析出形貌)和增大颗粒间分离力(增强颗粒运动、增大颗粒尺寸、施加外场力)等一系列抑制黏结失流方法；工业应用方面包括100公斤/天流化床氢气直接还原、1吨/天钒钛磁铁矿流化床直接还原和千吨级钒钛磁铁矿直接还原-电炉熔分等中间试验，目前正在与鞍钢集团等单位合作开展全球首套1万吨直接还原铁/年流化床绿氢直接还原工程示范。谨以此文缅怀叶渚沛先生、郭慕孙先生等老一辈科学家，以期推动流化床直接还原基础理论和技术研发的进步，为钢铁工业低碳重塑贡献智慧和力量。     

包覆式超细复合粒子的制备

综述了包覆式超细复合粒子的制备技术，包括机械法，异相凝聚法，种子异相聚合法，微乳液和沉积法等，主要介绍了每种制备技术的原理及过程中应注意的问题，并介绍了它们的新发展。