随机扰动下的库存投资决策模型

本文讨论的是库存投资的最优决策问题.不同于确定性q理论,对于引入了市场不确定性扰动的库存控制系统,文章建立了库存投资随机优化决策模型.从市场利率波动的角度对库存决策模型进行分析,得出的结论是:小的市场利率的扰动能够提高企业折现利润的预期,进而导致公司库存投资的上升.     

六铝酸盐结构及其在高温反应中的应用

六铝酸盐因其特殊的层状结构具有高温热稳定性;晶格中Al³⁺可被不同过渡金属和贵金属离子取代,具有活性组分可镶嵌性;镜面层排列疏松,为氧的优先扩散通道;以上结构特质为六铝酸盐在高温涉氧方面的应用奠定了坚实的基础。本综述从六铝酸盐的结构出发,详细讨论了六铝酸盐的结构类型（磁铅石型和β-Al₂O₃型）和金属取代对其微观结构（尤其是金属化学状态）的影响,并介绍了近年来六铝酸盐在高温涉氧反应,如CH₄催化燃烧、环保领域N₂O消除、航天推进级N₂O分解、甲烷化学链燃烧和重整中的应用,重点关注了六铝酸盐结构与性能的关联,最后对六铝酸盐未来研究方向作出展望。     

Rhodium-catalyzed carbonylation of 3-acyloxy-1,4-enynes for the synthesis of cyclopentenones

Functionalized cyclopentenones were synthesized by a Rh-catalyzed carbonylation of 3-acyloxy-1,4-enynes, derived from alkynes and α,β-unsaturated aldehydes. The reaction involved a Saucy-Marbet 1,3-acyloxy migration of propargyl esters and a [4 + 1] cycloaddition of the resulting acyloxy substituted vinylallene with CO.     

Adamantyl‐ and Furanyl‐Protected Nanoscale Silver Sulfide Clusters

The silver salts of 1‐adamantanethiol (AdSH) and furan‐2‐ylmethanethiol (FurCH₂SH) were successfully applied as building blocks for ligand‐protected Ag₂S nanoclusters. The reaction of the silver thiolates [AgSAd]_x and [AgSCH₂Fur]_x with S(SiMe₃)₂ and 1,5‐bis(diphenylphosphino)pentane (dpppt) afforded three different clusters with 58, 94 and, 190 silver atoms. The intensely colored compounds [Ag₅₈S₁₃(SAd)₃₂] ( 1 ), [Ag₉₄S₃₄(SAd)₂₆(dpppt)₆] ( 2 ), and [Ag₁₉₀S₅₈(SCH₂Fur)₇₄(dpppt)₈] ( 3 ) were structurally characterized by single‐crystal X‐ray diffraction and exhibit different cluster core geometries and ligand shells. The diameters of the well‐defined sphere‐shaped nanoclusters range from 2.2 nm to 3.5 nm.     

Fluorescent blood glucose monitor by hemin-functionalized graphene quantum dots based sensing system

In the present work, a highly sensitive and specific fluorescent biosensor for blood glucose monitoring is developed based on hemin-functionalized graphene quantum dots (GQDs) and glucose oxidase (GOx) system. The GQDs which are simply prepared by pyrolyzing citric acid exhibit strong fluorescence and good water-solubility. Due to the noncovalent assembly between hemin and GQDs, the addition of hemin can make hydrogen peroxide (H₂O₂) to destroy the passivated surface of GQDs, leading to significant fluorescence quenching of GQDs. Based on this effect, a novel fluorescent platform is proposed for the sensing of glucose. Under the optimized conditions, the linear range of glucose is from 9 to 300 μM, and the limit of detection is 0.1 μM. As unique properties of GQDs, the proposed biosensor is green, simple, cost-efficient, and it is successfully applied to the determination of glucose in human serum. In addition, the proposed method provides a new pathway to further design the biosensors based on the assembly of GQDs with hemin for detection of biomolecules.     

Rhodium(I)‐Catalyzed Benzannulation of Heteroaryl Propargylic Esters: Synthesis of Indoles and Related Heterocycles

A de novo synthesis of a benzene ring allows for the preparation of a diverse range of heterocycles including indoles, benzofurans, benzothiophenes, carbazoles, and dibenzofurans from simple heteroaryl propargylic esters using a unified carbonylative benzannulation strategy. Multiple substituents can be easily introduced to the C4–C7 positions of indoles and related heterocycles.     

Rhodium‐Catalyzed Intramolecular [5+2] Cycloaddition of Inverted 3‐Acyloxy‐1,4‐enyne and Alkyne: Experimental and Theoretical Studies

By switching the position of the alkene and alkyne, a new type of 3‐acyloxy‐1,4‐enyne (ACE) five‐carbon building block was developed for Rh‐catalyzed intramolecular [5+2] cycloaddition. An electron‐withdrawing acyl group on the alkyne termini of the ACE was essential for a regioselective 1,2‐acyloxy migration. This new method provided bicyclic [5.3.0]decatrienes that are different from previous methods because of the positions of the alkenes and the acyloxy group. Multiple mechanistic pathways become possible for this new [5+2] cycloaddition and they are investigated by computational studies.