Coordinating production and recycling decisions with stochastic demand and return

In this paper, the joint production and recycling problem is investigated for a hybrid manufacturing and remanufacturing system where brand-new products are produced in the manufacturing plant and recycled products are remanufactured into as-new products in the remanufacturing facility. Both the brand-new products and remanufactured products are used to satisfy customer demands. Returns of used products that are recycled from customers are assumed to be stochastic and nonlinearly price-dependent. A mathematical model is proposed to maximize the overall profit of the system through simultaneously optimizing the production and recycling decisions, subject to two capacity constraints — the manufacturing capacity and the remanufacturing capacity. Based on Lagrangian relaxation method, subgradient algorithm and heuristic algorithm, a solution approach is developed to solve the problem. A representative example is presented to illustrate the system, and managerial analysis indicates that the uncertainties in demand and return have much influence on the production and recycling policy. In addition, twenty randomly produced examples are solved, and computational results show that the solution approach can obtain very good solutions for all examples in reasonable time.     

假颗粒现象及其对再生铝镁碳制品性能的影响

对用后铝镁碳砖再生颗粒料的组成和结构特点进行显微分析,并通过改变混料方式以及不同粒度再生料的加入量研究假颗粒对再生铝镁碳制品结构与性能的影响.结果表明:用后铝镁碳砖再生料中含有约40%与废砖相组成和结构相似、骨料与基质并存于同一颗粒的二次颗粒,即所谓的"假颗粒",假颗粒的组成、结构及外形的均匀程度均远不如一次骨料颗粒;混碾可使用后铝镁碳砖再生料中假颗粒发生二次破碎,且粒度越大,发生二次破碎的颗粒数量越多;假颗粒二次破碎导致再生制品的粒度组成发生改变,进而影响其密度和耐压强度.     

钱谦益唐宋兼宗的祈向与清代诗风新变

“诗必盛唐”是明代具有强势传播力的诗学观念 ,其消极影响是法唐而赝 ,自狭诗道。当时虽有接纳宋诗的呼唤 ,但难以形成趋势。明末清初 ,钱谦益以唐宋兼宗为新的诗学选择 ,具体途辙是以崇尚杜诗为由唐向宋的起点 ,在诗坛大力导入宋代诗风 ,融铸异质 ,求变创新。以沉潜深厚改变浮薄肤浅 ,以性情为本取代唯务格调 ,从而形成宏衍阔大的气局 ,使诗歌创作具有多元组合的美质。钱氏的这一诗学选择开启了清代新诗风     

Preparation of superhydrophobic silver nano coatings with feather-like structures by electroless galvanic deposition

Superhydrophobic silver nanocoatings with feather-like morphology are fabricated on copper substrates by electroless galvanic deposition. The coating exhibit superhydrophobicity with a contact angle of 156.4° and glide angle of 4° without any further surface modification. Scanning electron microscope (SEM), X-ray diffraction (XRD) and contact angle measurements are used to investigate the morphology, crystal structure and superhydrophobicity, respectively, of the coatings. The coatings exhibit high thermal stability; their water contact angle did not change when the coatings were heated to 200°C for 2 h. The mechanism of superhydrophobicity of the silver coating is discussed based on the work of Amirfazli, Wenzel and Cassie.     

中国现代毒理学的形成与发展

毒理学是关系人类健康的一门学科,人类与毒物斗争的历史是人类文明史中重要的篇章.生物学研究的每一次进展都使得毒理学产生新飞跃,从五四运动至今的90多年内,我国现代毒理学发展经历了起步、取得阶段性成果和开拓创新三个不同的发展阶段.     

关于机器证明

本文简介机器证明的理论与实践．并附一篇关于用模型论方法证明无限地图的四色定理．     

提高水泥粉磨能效的探索

水泥粉磨系统是水泥生产过程中的重要环节.在保证水泥质量的情况下,最大限度地降低粉磨系统的能耗对于节约能源及提高企业经济效益具有重要的现实意义.本文介绍了目前水泥粉磨设备的选型情况,并提出选用立磨终粉磨系统将成为水泥粉磨的发展趋势.     

Comparison study of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin microspheres

To compare two microspheres of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin loaded theophylline as pulmonary sustained drug delivery carriers, the characteristics and ciliotoxicity were studied. The drug loadings of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin microspheres were 21.09% and 21.42%, and the encapsulation efficiencies were 91.40% and 92.80%. The distributions of 50% (d _0.5) of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin microspheres were 4.89 and 5.83 μm, respectively. Both microspheres showed spherical shape with smooth or wrinkled surfaces. FT-IR of chitosan/β-cyclodextrin microspheres demonstrated that theophylline had formed hydrogen bonds with chitosan and β-cyclodextrin, while for the carboxymethyl chitosan/β-cyclodextrin microspheres theophylline had interaction with carboxymethyl chitosan. The moisture absorption showed that an equilibrium was reached within 24 h. The two microspheres possessed better adaptability. In vitro release of theophylline from chitosan/β-cyclodextrin microspheres was slower than that from carboxymethyl chitosan/β-cyclodextrin microspheres at pH 6.8. Biography: LI Ruobao(1968–), male, Associate professor, research direction: foundation research of respiratory system.     

《三字经》思想中的当代价值论略

《三字经》高度浓缩着中国传统文化的和谐价值思想,通过辩证逻辑的方法,具体分析了其中蕴含的生态伦理因素,独创性的探索《三字经》中人与自然的和谐环境、和谐的社会环境、"诚信"的人际环境的内涵,其目的在于突破传统启蒙读物的伦理水平,更好地促进社会主义和谐社会的建设,对文化的支撑、道德的修养、学习的提升起到了有益的借鉴。     

“范畴”与“概念”之辩:一个认知问题的探讨

作为认知研究的工具,西方经典哲学中的"范畴"和"概念"体现了哲学家们探索世界、语言、心智的视角和方法,相对容易把握;现代认知科学中的"范畴"和"概念"既反映了学者们的各自取向,也掺杂着研究中的思维混乱,情况非常复杂。从认知本身的多个维度,在同一平面内对"范畴"和"概念"进行考察是个新的思路,也呈现出了一幅较为清晰的图景。