A Chemical History of Polycyclic Musks

Musk odorants are ubiquitous in fine perfumery as well as household products, and are divided into four main families, the nitromusks, the macrocyclic musks, the polycyclic aromatic musks, and the alicyclic musks, following their order of appearance on the perfumery market. This article presents the scientific and industrial adventures during the discovery of the seven commercial polycyclic musks, which invigorated the aroma chemistry corporations during the second half of the 20th century, resulting in relentless competition. Research and development strategies are exposed, and reactivity, analytical, mechanistic, and structure–activity relationships aspects are discussed as well as some biographical elements of the main scientific actors, and some fine perfumery examples are given as illustrations of their use.     

Synthetic Strategies for (−)‐Cannabidiol and Its Structural Analogs

(?)‐Cannabidiol ((?)‐CBD), a non‐psychoactive phytocannabinoid from Cannabis, and its structural analogs have received growing attention in recent years because of their potential therapeutic benefits, including neuroprotective, anti‐epileptic, anti‐inflammatory, anxiolytic, and anti‐cancer properties. (?)‐CBD and its analogs have been obtained mainly based on extraction from the natural source; however, the conventional extraction‐based methods have some drawbacks, such as poor quality control along with purification difficulty. Chemical‐synthetic strategies for (?)‐CBD could tackle these issues, and, additionally, generate novel (?)‐CBD analogs that exhibit advanced biological activities. This review concisely summarizes the historic and recent milestones in the synthetic strategies for (?)‐CBD and its analogs.     

Getting Ring‐Closing Metathesis off the Bench: Reaction‐Reactor Matching Transforms Metathesis Efficiency in the Assembly of Large Rings

Reported is the first study of the influence of reactor configuration on the efficiency of a challenging ring‐closing metathesis (RCM) reaction. With the intention of increasing the generality of RCM scaleup and reducing its dependence on substrate modification, macrocyclization of an unmodified, low effective‐molarity diene was explored using different reactor types, in conjunction with a commercial, homogeneous Grubbs catalyst. Optimized performance is compared for a conventional batch reactor (BR), a continuous plug‐flow reactor (PFR), and a continuous stirred‐tank reactor (CSTR). In the PFR, maximum conversion is achieved most rapidly, but product yields and selectivity are adversely affected by co‐entrapment of ethylene with the catalyst, substrate, and product in the traveling “plug”. Use of the CSTR, in which ethylene is efficiently swept out, affords an order‐of‐magnitude increase in total turnover numbers, and reduces the required catalyst loadings by 25× relative to the BR (to 0.2 mol %), while improving RCM yields and selectivity to quantitative levels. Continuous‐flow methodologies that support liberation of the ethylene co‐product thus show great promise for industrial uptake of RCM.     

外商直接投资对安徽产业结构影响的实证分析

外商直接投资不仅为安徽带来了经济建设所急需的资金、技术和管理经验,创造了就业机会,增加了财政收入,还促进了安徽产业结构的升级。本文通过分布滞后模型分析了外商直接投资对安徽三大产业生产总值的效应,从而说明外商直接投资会对安徽产业结构产生影响。     

轨道交通产业全产业链的韧性-脆弱性研究

首先,论述了韧性-脆弱性理论,界定了韧性-脆弱性的内涵．其次,分析了全产业链的产业韧性-脆弱性的形成机理,包括全产业链韧性-脆弱性和轨道交通产业全产业链韧性-脆弱性两个概念的界定．第三,构建了轨道交通产业全产业链韧性-脆弱性评价指标,内部评价指标来自于企业管理水平等5个影响因子,外部评价指标来自于资源禀赋等3个影响因子．第四,实证分析了轨道交通产业全产业链韧性-脆弱性评价,得出8个指标分别影响该产业全产业链韧性-脆弱性的情况是：企业规模、技术密集度、交通成本和对外开发程度这4个指标的影响显著,劳动力成本对产业影响程度不大,消费购买力和专利申请数及政策支持影响不显著．最后,从提高产业技术创新能力等5个方面,提出缓解轨道交通产业全产业链韧性-脆弱性的对策建议．     

产业集群协同创新知识共享策略的微分博弈研究

针对产业集群协同创新中核心企业和配套企业的知识共享问题, 通过构建微分博弈模型, 运用HJB方程分别考察三种知识共享博弈情形下核心企业和配套企业的最优知识共享策略。通过三种博弈结果的比较分析发现:Stackelberg主从博弈情形下, 知识共享投入补贴作为一种激励策略可促进配套企业知识共享意愿、双方各自知识共享收益以及双方知识共享总收益均优于Nash非合作情形;协同合作博弈情形下双方各自知识共享意愿、各自知识共享收益和双方知识共享总收益均优于非合作情形, 且收益分配系数α存在一个阈值, 可实现双方个体收益的帕累托最优。最后, 通过数值算例分析验证了理论推导的结果。     

中国高技术产业的技术创新影响因素:基于面板数据模型的实证检验

利用中国16个高技术行业的面板数据,对高技术行业的技术创新影响因素进行了实证分析,不仅研究了R&D投入对高技术行业技术创新的影响,还考虑了行业融资结构、外资企业研发的技术溢出效应、产权结构、企业规模以及市场集中度等因素的影响作用.     

四川产业结构与就业结构变动关系的实证研究

四川省是农业人口大省,而在西部十二省中四川的经济发展水平处于前列。因此,对四川省产业结构和就业结构的研究对西部乃至全国经济的发展有着重要的意义。为了使四川省产业结构和就业结构之间的关系更加明确,本文运用Granger因果关系检验得出,四川省产业结构变动是引起就业结构变动的原因。在此基础上利用Johansen协整关系检验、线性回归等方法测算出产业结构对就业结构影响程度、做出各产业对就业贡献率的折线图并分析了产业结构与就业结构的偏离度。最后得出结论:第一产业产值的增长不仅无法拉动就业而且对业已存在的剩余劳动力还具有一定的挤出效应,第三产业具有较大的发展空间和吸纳就业的能力,第二产业次之。     

固定资产投资对产业结构变动的影响分析

产业结构提升是一国或地区经济素质的重要表现,在产业结构演变的过程中,固定资产投资起着推动和促进的作用。本文运用成分分析的基本原理,对1980年以来我国产业结构的变化以及与固定资产投资活动的关系进行了测算分析。主要内容包括:产业结构成分变动的描述,产业结构成分变动检验,产业结构与固定资产投资之间关系的成分回归模拟等。     

基于主成分分析的广东省邮电业发展状况研究

通过主成分分析方法,选取2006、2011和2016年广东省各市邮电业务数据,对广东省21个地级市的邮政和通信事业发展状况进行分析和发展水平层次划分,从时间和地域空间两个维度对广东省各地区邮电业发展情况进行排名分组.结果表明,当前广东省各地区邮电业发展状况存在显著的地区差异.