New Solution Approaches to the General Single- Machine Earliness-Tardiness Problem

This paper addresses the general single-machine earliness-tardiness problem with distinct release dates, due dates, and unit costs. The aim of this research is to obtain an exact nonpreemptive solution in which machine idle time is allowed. In a hybrid approach, we formulate and then solve the problem using dynamic programming (DP), while incorporating techniques from branch-and-bound (BB). This approach (DP-BB) has been proven to be effective in solving certain types of scheduling problems. We further propose a new adaptation of the approach to a general problem with a nonregular objective function. To address some shortcomings of DP-BB, we also apply a BB approach in which partial dynamic programming dominance (BB-PDP) is exploited. Computational experiments were conducted with randomly generated test instances in order to evaluate the effectiveness of the two approaches. The results clearly showed that our new approaches can solve all the instances with up to 40 jobs and most of the instances with 50 jobs, which outperforms those frequently used approaches in scheduling research.     

A New Algorithm for Stochastic Discrete Resource Allocation Optimization

Stochastic discrete resource allocation problems are difficult to solve. In this paper, we propose a new algorithm designed specifically to tackle them. The algorithm combines with the Nested Partitions method, the Ordinal Optimization techniques, and an efficient simulation control technique. The resulting hybrid algorithm retains the global perspective of the Nested Partitions method and the fast convergence properties of the Ordinal Optimization. Numerical results demonstrate that the hybrid algorithm can be effectively used for many large-scale stochastic discrete optimization problems.     

Integrated optimisation on flow-shop production with cutting stock

This paper addresses the integrated scheduling optimisation on flow-shop production with one-dimensional cutting stock in make-to-order environments. The upstream cutting-stock process provides the items for the downstream production, while the flow-shop production can be executed only when the required items are released. The efficient schedules on cutting plan and the production sequence should be determined in a coordinated manner to improve the overall efficiency. This study aims to find an integrated schedule to minimise the makespan of the entire manufacturing process. We develop a hybrid algorithm by integrating a local search method and some efficient strategies under the nested partitions framework. Numerical experiments show that the proposed approach is capable of achieving high-quality solutions within a reasonable time.     

Micro/nanocellular polyprolene/trans-1,4-polyisomprene (PP/TPI) blend foams by using supercritical nitrogen as blowing agent

Toughed polypropylene (PP) foams, with the combination of blending with trans-1,4-polyisoprene (TPI) and micro/nanocellular structure in the matrix, were prepared using a batch foaming process and N₂ as the blowing agent. The incorporation of TPI in the PP matrix induces the enhanced formability and the slightly improved ductility and toughness compared to the neat PP. The simultaneous existence of the TPI phase and micro/nanocellular structure makes the fracture behavior follow the shear yielding of a bundle of fibrils in the tensile load direction. The results of mechanical properties measurements show that the notched Izod impact strengths of foamed PP/TPI blend are two to three times larger than those of the unfoamed counterparts. The PP/TPI blend foam with 5phr TPI content shows the highest impact strength when the foaming temperature is 140°C, which is fivefold increase over that of the neat PP. The enhanced ductility and toughness of PP/TPI foams were found with the increasing foaming temperature. The insert of micro−/nanocellular in PP/TPI blends simultaneously makes the notched impact strength increase significantly, tensile strength decrease, and elongation at break increase obviously, which provides the possibility to combine the higher impact strength and toughness with the advantage of microcellular foaming. POLYM. ENG. SCI., 60:211–217, 2020. © 2019 Society of Plastics Engineers     

栀子油对小鼠急性酒精性肝损伤的保护作用

研究栀子油对酒精所致小鼠急性肝损伤的保护作用。将72只小鼠随机分为正常组,模型组,栀子油低、中、高剂量组(0.3、0.6、1.2 g/kg)和阳性对照组(联苯双酯滴丸,200 mg/kg),每组12只,正常组和模型组灌胃等量的0.5%吐温-80溶液。采用改良后的造模方法(连续给药10 d后灌胃56%乙醇,15 m L/kg,连续灌胃2次)建立小鼠急性肝损伤模型,测定小鼠血清中AST、ALT、γ-GT和TG水平,检测肝组织匀浆中ADH、SOD、MDA、GSH和GSH-Px的含量,RT-PCR检测肝组织中TNF-αmRNA的表达量,HE染色光学显微镜分析小鼠肝损伤程度。结果表明:与模型组相比,栀子油各剂量组均能降低血清ALT、AST、γ-GT和TG的含量,提高ADH、GSH、GSH-Px、SOD活性,降低肝组织MDA的产生,下调TNF-αmRNA的相对表达量,肝组织变性及坏死等病理症状明显改善,尤以栀子油高剂量组效果最佳。栀子油对酒精所致小鼠急性肝损伤有保护作用,其保护机制可能与增强肝组织脂质代谢水平、提高抗氧化酶体系活力、抑制氧化应激反应及炎性因子表达相关。     

高温超导量子干涉磁强计的发展现状及其应用

本文介绍了高温超导量子干涉磁强计的发展现状及其在生物磁测量、地磁测量、无损探伤及扫描SQUID显微镜等方面的应用。     

Ce2Mg17及其氢化物添加剂对LiBH4的放氢作用机理研究

为改善LiBH4体系的可逆吸放氢性能,将Ce2Mg17合金(简称为CM)及其氢化物(CeH2.51和MgH2,简称为CMH)分别与LiBH4球磨4 h制得LiBH4-0.02CM和LiBH4-0.02CMH复合储氢体系,采用MS、TPD、XRD和FT-IR等测试手段研究了不同状态Ce-Mg添加剂对复合储氢体系可逆吸放氢性能的影响及其作用机制。结果表明:Ce2Mg17合金本身对改善LiBH4吸放氢性能没有明显作用;而Ce2Mg17氢化物(即MgH2和CeH2.51)可降低复合体系中LiBH4的放氢温度和提高LiBH4的放氢速率,并可明显改善体系的可逆吸放氢性能。进一步分析表明,MgH2和CeH2.51对LiBH4的协同改性作用是有效降低LiBH4热力学稳定性、提高LiBH4-Ce-Mg复合体系可逆吸放氢性能的主要原因。     

利用地层测试压力资料估算油层动用程度和剩余油饱和度

利用电缆地层测试器（FMT）资料估算油藏无水采油期剩余油饱和度,是其在油田开发阶段的重要应用之一。在引入油层动用程度和油层采出程度的概念之后,笔者提出一种确定无水采油期当前油层剩余油饱和度的新方法,即利用油层压力资料来估算剩余油饱和度。当油层处于无水采油期时,油层不含水,此时油层电阻率与原始油层电阻率变化不大,由常规电阻率计算的剩余油饱和度与原始含油饱和度差别不大,易得出油层“没有被动用”的假象。因此,应当利用FMT资料来估算剩余油饱和度。对于开发生产井,常规电阻率测井资料和FMT资料综合估计剩余油饱和度的方法是互为补充,缺一不可的。     

关于地质灾害村庄搬迁规划的思考

文章以长治市地质灾害村庄搬迁为实例．分析了地质灾害村庄的现状布局、生产生活等状况。主要探索了岭上、龙塘两个搬迁治理村庄的土地治理方法和措施,以及村庄搬迁的规划编制等问题,为类似村庄的治理和搬迁提供参考范例。     

浅析高校院系学生思想政治教育评估指标体系构建中的问题

高校院系学生思想政治教育评估指标体系是一个多角度、多侧面、高难度的体系,构建这一体系要清晰界定院系学生思想政治教育评估及其指标体系的内涵,要遵循一定的准则和指导思想,要讲究实施的方式方法.