Common due date assignment scheduling for a no-wait flowshop with convex resource allocation and learning effect

This article addresses the no-wait flowshop scheduling problem with simultaneous consideration of common due date assignment, convex resource allocation and learning effect in a two machine setting. The processing time of each job can be controlled by its position in a sequence and also by allocating extra resource, which is a convex function of the amount of a common continuously divisible resource allocated to the job. The objective is to determine the optimal common due date, the resource allocation and the schedule of jobs such that the total earliness, tardiness and common due date cost (the total resource consumption cost) are minimized under the constraint condition that the total resource consumption cost (the total earliness, tardiness and common due date cost) is limited. Polynomial time algorithms are developed for two versions of the problem.     

3-羟基-4-吡啶酮类螯合剂在镓放射性药物中的 研究进展及展望

目前，在肿瘤等重大疾病的早期诊断中，PET/CT（或PET/MRI）是灵敏度最高、分辨率最好的医学影像手段。PET/CT（或PET/MRI）依赖于PET药物，很大程度上依赖于¹⁸F PET药物。然而，随着世界上第一个⁶⁸Ga药物（⁶⁸Ga-DOTATATE）获得美国FDA批准进入市场，⁶⁸Ga及其药物的研究正受到越来越多的关注。本文首先介绍了镓的基本核性质和化学性质，然后提出了金属双功能螯合剂的设计要求，并讨论了一些常用镓螯合剂的优缺点。由于3-羟基-4-吡啶酮基团对三价镓离子具有高的亲和力和选择性，因此，特别重点关注了3-羟基-4-吡啶酮多齿螯合剂在镓放射性药物中的最新研究进展。最后，还对3-羟基-4-吡啶酮多齿螯合剂在镓放射性药物中的应用前景进行了展望。     

Chemoenzymatic Synthesis of Fragrance Compounds from Stearic Acid

Fatty acids are versatile precursors for fuels, fine chemicals, polymers, perfumes, etc. The properties and applications of fatty acid derivatives depend on chain length and on functional groups and their positions. To tailor fatty acids for desired properties, an engineered P450 monooxygenase has been employed here for enhanced selective hydroxylation of fatty acids. After oxidation of the hydroxy groups to the corresponding ketones, Baeyer–Villiger oxidation could be applied to introduce an oxygen atom into the hydrocarbon chains to form esters, which were finally hydrolyzed to afford either hydroxylated fatty acids or dicarboxylic fatty acids. Using this strategy, we have demonstrated that the high-value-added flavors exaltolide and silvanone supra can be synthesized from stearic acid through a hydroxylation/carbonylation/esterification/hydrolysis/lactonization reaction sequence with isolated yields of about 36 % (for ω−1 hydroxylated stearic acid; 100, 60, 80, 75 % yields for the individual reactions, respectively) or 24 % (for ω−2 hydroxylated stearic acid). Ultimately, we obtained 7.91 mg of exaltolide and 13.71 mg of silvanone supra from 284.48 mg stearic acid.     

The 3-dimensional morphology of dendrite during equiaxed solidification of an Al-5 wt.% Cu alloy

In a sample quenched during equiaxed solidification of an Al-5 wt.% Cu alloy, the multi-scales 3-dimensional morphology of equiaxed dendrite was observed. The slim primary stem and secondary branches constitute the frame of dendrite, and rows of dense tertiary branches further divide the 3-dimensional space. In the divided space, the quartic branches grow further. The dendritic branches,which are perpendicular to each other, can change their growth directions and coalesce into a whole. In the tertiary branches and quartic branches, the formation of double branch structures is induced by competitive growth. The branch that wins in the competitive growth will produce a cabbage-like structure by wrapping the failed branches. In addition, the side branch can also wrap the original parent branch to produce cabbage-like structures. Depending on the historical growth direction, the dendritic arms can form vein-like and spicate structures, and the shapes of single dendritic arm may be the cylinder, plate and trapezoid platform. According to the compositions and etching morphology, the single dendritic arm in the final solidification structures should coalesce from a fine porous structure. The porous structures at different length-scales are principally induced by the preferential growth. Based on 3-dimensional morphology of equiaxed dendrite, a new research object for the investigation of microsegregation was suggested.