基于多尺度投入-产出表的中国对外贸易产业结构调整多目标优化

出口贸易引发的资源流失风险是当今研究的热点. 本文动态地分析了出口贸易引起的资源流出变动及其影响因素, 并对2018-2022年中国地区出口贸易进行优化调整. 首先, 本文利用行业间投入-产出表和资源消耗数据计算中国各行业的直接和完全资源消耗系数; 其次, 利用结构分解模型挖掘出口导向的隐含资源流出量变动的主要原因; 随即, 将45个行业进行聚类分析, 探讨未来各行业的节约资源潜力和调整路径; 最后基于情景分析和多目标优化理论, 从出口贸易结构, 贸易额和技术发展视角对中国未来出口贸易进行模拟分析. 实证分析结果表明: (1) 直接消耗强度, 技术进步, 出口总量和出口结构等4个影响因素中, 出口额对资源流失风险的贡献率最大. 直接能源消耗强度有助于降低因出口导致的能源流出, 而完全消耗水资源强度的降低大大减少了资源流失风险, 符合现实； (2) 以2017 年为基准年, 利用多目标优化模型求解2018-2022年出口结构和出口量, 结果表明优化结果有利于降低资源流出量. 通过调整未来各行业资源消耗强度, 优化结果发现技术提升带来的资源节约优势逐渐增强, 本文认为, 为技术改善的资金(人员)投入的边际产出呈现逐渐增强效应.     

基础研究空间网络关联结构及影响因素分析

以我国31个省区市2009—2018年国家自然科学基金面上项目为样本,采用改进的引力模型构建省区市之间的基础研究关联关系,在此基础上利用社会网络分析模型分析我国省区市之间基础研究的空间网络结构演化及影响因素。研究表明:网络整体的空间关联性逐步增强,网络效率呈现出平缓的下降趋势;东部沿海经济发达地区并未利用自身的优势对其他地区产生推动作用。基础科研空间关联网络划分为双向溢出、经纪人、净溢出和净受益4个板块,板块内部的联系要大于板块之间的联系。地理位置临近、申请机构数量、科研人员、正副高职数量对基础科研的空间关联结构有显著性影响。     

膝关节骨性关节炎步态分析特征及3D矫形鞋垫设计应用

 概述了2种步态分析实验系统、实验原理和KOA患者下肢三维步态的改变；由于下肢生物力学的复杂性和研究技术的局限性，3D矫形鞋垫设计目前仍处于初级阶段，产品的治疗效果尚无统一意见并且未大量生产使用，因此对3D矫形鞋垫在KOA中的应用原理及制作过程进行深入探讨，明确KOA患者膝关节周围动力和静力结构变化，将其应用于3D矫形鞋垫的设计和生产，为早期KOA保守治疗提供重要解决方案，既能够患者满足舒适性和功能性的双重需求，又能使制造周期和成本显著降低。     

LINE-SERU转化的评价分析——以某医疗制造企业实施SERU为例

面对日益增加的需求不确定性及激烈的市场竞争,SERU (赛汝)生产方式应运而生,并广泛应用于日本电子装配制造企业.国内一些制造装配业正尝试将传统的流水线转化为SERU装配方式,简称LINE-SERU转化.一些文献报道了日本企业实施LINE-SERU转化的效果,而学术界对国内企业实施SERU装配方式的生产组织与运行效率缺乏理论分析和标杆分析.本文以国内某医疗器械装配企业实施LINE-SERU转化为例,通过理论分析和数据分析,系统地讨论了国内企业实施LINE-SERU转化的背景、过程、影响因素及生产组织形态,从多维度比较分析了改善效果及原因;总结了国内企业与日本企业在SERU系统的构建方式、布局形态和企业文化等方面的差异.研究发现,中国企业处于LINE-SERU转化的初期,SERU系统具有其独特的组织形式,在提高生产效率、缩短生产周期、减少在制品数量、精简作业人数和降低次品率等方面均有显著提升,但改善效果不同于日本企业.建议国内企业依据其人力资源特征构建SERU系统、优化单元布局、培育以人为本的企业文化,以提高系统柔性和改善效率.     

水热法制备不同形貌纳米片状MoS_2的光催化性能

二硫化钼是类似于石墨烯的二维层状材料,其优异的磁学性能、电学性能、催化性能和光学性能受到了科研人员的广泛关注.通过水热法制备出4种不同形貌的二硫化钼纳米片.对二硫化钼样品进行扫描电子显微镜测试,以200 W钨丝灯为光源,在暗箱中进行甲基橙溶液的降解测试.通过紫外可见光分光光度计对测试样品溶液进行吸光度测试,得出纳米片状的二硫化钼光催化降解甲基橙溶液降解率最高.     

烃族组成对柴油储存安定性影响研究

针对柴油储存过程中质量衰变问题，利用典型柴油样品，开展烃化合物对中国成品柴油储存安定性影响规律研究。烃组成分析测定结果表明，柴油中总芳烃和链烷烃之间存在很强的相关性（相关系数为0.90）。综合采用相关分析、逐步线性回归等方法，建立了安定性指标与烃组成的关联模型，拟合验证表明模型可靠，可以直接用于柴油储存安定性预测；研究确定了柴油储存安定性的主要影响物质，按照对储存安定性指标影响的严重程度将烃类物质分为三个等级，其中苊烯和三环芳烃对柴油质量衰变影响最大，链烷烃对十六烷值和热值影响最大。     

Forecasting the duration of short‐term deflation episodes

The paper proposes a simulation‐based approach to multistep probabilistic forecasting, applied for predicting the probability and duration of negative inflation. The essence of this approach is in counting runs simulated from a multivariate distribution representing the probabilistic forecasts, which enters the negative inflation regime. The marginal distributions of forecasts are estimated using the series of past forecast errors, and the joint distribution is obtained by a multivariate copula approach. This technique is applied for estimating the probability of negative inflation in China and its expected duration, with the marginal distributions computed by fitting weighted skew‐normal and two‐piece normal distributions to autoregressive moving average ex post forecast errors and using the multivariate Student t copula.     

大尺寸工程模型试验中的相似材料配比试验研究

大型物理模型试验是研究复杂工程问题的重要方法，如何快速、准确地确定相似材料配比是试验中至关重要的一环.为降低试验成本、简化试验步骤、充分调用原料性能，采用河砂、水泥和石膏这三种最普通的原料，以骨胶比(河砂与水泥石膏的质量比)和水膏比(水泥与石膏的质量比)为变量，进行了45组对比试验，对相似材料的物理及动、静力学参数进行了研究.获得了以河砂、水泥和石膏为原料配制的相似材料各物理量的变化区间；探讨了骨胶比和水膏比对相似材料各物理量的控制作用，并对比了其敏感性；基于多元线性回归分析建立了各因素与物理量间的定量关系，得到的拟合公式能较好地描述相似材料的性质.     

Coral reef tanaidacean assemblages along the SW and SE Gulf of Mexico: biodiversity,geographic distribution and community structure

The biodiversity, geographic distribution, and community parameters of the benthic tanaidaceans associated with three coral reefs along the SW and SE Gulf of Mexico were analysed. A total of 15,525 specimens were grouped in 36 species. The highest value of abundance was found in the PNSAV with 6382 tanaidaceans. The PNSAV presented 30 species, the ANPT-L 16 species, and the SABS 17 species. The species with the widest distribution were Pseudonototanais sp., Condrochelia dubia, Leptochelia forresti, Synapseudes sp., Haplopolemius propinquus, Alloleptochelia longimana, and Paradoxapseudes bermudeus. In the Veracruz System Reef, the highest abundance was recorded for Condrochelia dubia and Pseudonototanais sp. The highest value of diversity was obtained in the SABS (3.08 bits/ind in the reef Bajo Diez), and the lowest value was found in the PNSAV (0.07 bits/ind in the reef Isla de Enmedio). The highest value of abundance was found in coral rubble and macroalgae. A significant relationship between depth and specific richness was found in the three reef systems. Using cluster analysis, three groups were found in each system, mainly related to the proximity to the coast and to urban areas. This is one of the first studies to show the specific substrate and attributes of three communities of tanaidaceans along the SE–SW coast of the Gulf of Mexico.     

Redescription of Retilaskeya horrida (di Monterosato, 1874) comb. nov. and a re-evaluation of the taxonomic affinity of the genus Retilaskeya (Caenogastropoda: Triphoroidea)

The family Cerithiopsidae H. Adams and A. Adams, 1853 is distributed worldwide, and comprises around 800 extant species divided into ~40 genera. The most speciose genus within the family is Cerithiopsis Forbes and Hanley, 1850, a taxon currently used as a general receptacle rather than as a proper phylogenetic lineage. We hereby redescribe the rare species Cerithiopsis horrida di Monterosato, 1874, review its nomenclature, known material, and distribution as well as figure the entire protoconch, operculum, and radula for the first time. Our results highlight extreme differences between ‘Cerithiopsis’ horrida and the Cerithiopsis type species Cerithiopsis tubercularis (Montagu, 1803) and strong morphological and radular similarities with species belonging to the genus Retilaskeya Marshall, 1978. A wide discussion lists several taxa that might be ascribed to the same group of species, which presumably constitute a different worldwide lineage. Pending relevant molecular phylogenetic studies of the Triphoroidea Gray, 1847, for morphological conformity we suggest transferring ‘Cerithiopsis’ horrida to the genus Retilaskeya, and the same action is presumably appropriate for its possible sister species ‘Cerithiopsis’ leopardus Rolán and Gori, 2013. Finally, Retilaskeya better conforms to Newtoniellidae Korobkov, 1955 than Cerithiopsidae.