我国医疗器械产业集中度影响因素的实证研究

文章首先对我国医疗器械产业集中度进行测算,发现产业集中度呈持续上升态势.之后,采用线性回归分析和灰色关联分析对我国医疗器械产业集中度的影响因素进行分析.回归分析显示规模经济、生产企业进入率和股权投资有助于提高产业集中度,而产品差异率则阻碍了产业集中度的提高.灰色关联分析显示上述4种因素均对产业集中度具有重要影响,我国医疗器械产业集中度的变化是4种因素共同作用的结果.     

长征国家文化公园沿线红色旅游经典景区网络关注格局及影响因素

以长征国家文化公园沿线15个省区的红色旅游经典景区为研究对象,运用季节集中度指数、地理集中度、变差异系数等方法探讨2015—2022年沿线红色旅游经典景区网络关注度的时空特征及影响因素。结果表明：(1)从时序上看,2015—2022年景区网络关注度整体特征呈现波浪式增长的稳定演变趋势,且季节性差异较小,全年分布较为均匀;(2)从空间上看,东-中-西部地区关注度差异性呈明显下降趋势,集聚程度较低,省域间网络关注度的地域空间格局相对稳定,均衡性逐渐增强;(3)景区层面,根据季节差异性来划分,景区数量呈“金字塔”结构,单峰型景区季节差异性特征显著,多峰型景区季节差异较小;(4)教育发展水平、区域人口量级水平、交通发展状况、经济发展水平、互联网发展水平综合作用促成了长征国家文化公园沿线红色旅游经典景区网络关注度的关注格局,而红色旅游发展水平对其影响效果不显著。     

安徽省承接产业转移与创新产出的非均衡格局研究

优化承接产业转移和创新产出空间布局对充分发挥产业转移的创新效应具有重要意义.采用地理集中度、不一致指数、不均衡指数及回归分析等方法对2010—2016年安徽省承接产业转移与创新产出的空间格局及影响因素进行研究.结果表明:1)安徽省承接产业转移和创新产出地理集中度具有较强的一致性,皖江城市带的集中度都高,而皖西、皖北、皖南的大部分地区集中度低;2)安徽省大部分地市的产业转移集中度超前于创新产出集中度,皖江城市带除了合肥市、安庆市外以及皖西北大部分地区的不一致指数都呈上升趋势,皖西以及皖南大部分地区的不一致指数呈下降趋势;3)安徽省承接产业转移与创新产出的不均衡指数呈波动-稳定-明显上升的阶段特征;4)安徽省创新能力的提升主要依靠科技投入,但产业转移的溢出效应作用同样较显著.FDI、传统基础设施条件、科技人才、经济发展和科技政策的作用也相对较大,通讯基础设施水平和创新联系的作用较小.     

基于SSM-GIS的山西省资源型县域经济发展时空演变及发展机制研究

改革开放以来,资源型县域凭借资源优势和市场机遇,使得以煤炭资源为主要生产对象的第二产业迅速成为主导产业.本文运用变异系数、人均产值系数和偏离—份额分析等方法,对2005年~2015年山西省17个资源型县域总体经济和第二产业发展的时空演变格局进行分析.结果表明:(1)资源型县域经济呈现发展差异在波动中逐步扩大的趋势;(2)第二产业在山西省和全国产业发展水平中具有较高地位,相对优势明显;(3)空间上,第二产业专业化程度和产业集中度呈"火"字布局;(4)第二产业发展机制类型主要分为结构优化且竞争力增强型、结构优化但竞争力减弱型.     

产品市场竞争对资本结构的双维度影响机制研究——基于微观和中观视角

随着产品市场竞争会对资本结构产生影响这一观点逐渐被学术界所肯定,学者们发现企业自身具有的竞争优势与所处的行业环境都会对企业的资本结构决策行为产生影响。从微观(企业)层面和中观(产业)层面入手,分析企业市场势力、产业集中度以及二者的共同作用对资本结构决策的影响机理。研究发现:在垄断型行业,企业市场势力与负债水平呈负相关;在竞争型行业,企业市场势力与负债水平呈正相关。即产业集中度负向调节企业市场势力与资本结构的负向相关关系。因此,处于不同行业环境、竞争优势不同的企业要选择适合自己的负债水平,实施合理的竞争战略。     

环境能源约束下的中国石化产业全要素生产率Malmquist指数分析

在环境和能源因素约束的视角下,运用Malmquist指数法对中国石化产业的全要素生产率进行测算,探讨了中国石化产业全要素生产率,结果表明,在考虑了环境和能源因素后,2001-2010年我国石化产业全要素生产率的平均增长率为10.2％,主要原因是技术进步水平的提高;如不考虑能源和环境因素,石化产业的全要素生产率呈下降趋势,属于能源消耗和污染物排放较大的行业.     

1960—2011年秦岭南北地表干湿变化时空特征

运用P-M模型、气候倾向率及相关分析等方法,分析秦岭南北近52年地表干湿变化特征及其影响因素.结果表明:(1)潜在蒸散量(ET0)和干燥度指数(I)均呈现由南向北逐渐增加的空间分布型式;(2)ET0呈下降趋势,降速为-0.314mm/a(P0.05),其中1993年之前下降趋势显著,为-2.699mm/a(P0.01);(3)I呈缓慢上升趋势,增速为0.022/10a,在空间上呈现中部下降、两侧上升的分布型式,上升和下降趋势区域分别占62.62%和37.38%;(4)各年代干湿分界线变化显著,20世纪90年代最干旱,21世纪干燥程度有所缓解;(5)秦岭南北地表干湿状况及干湿分界线的变化主要归因于相对湿度、日照时数及降水量的变化.     

中国沿海集装箱港口集中度研究

利用行业集中度对我国沿海集装箱港口行业的市场结构演化过程进行分析.分析发现,近30年来,我国集装箱港口行业的市场结构由最初的寡占Ⅰ型发展到如今的寡占Ⅲ型,并且集中度有进一步下降的趋势,市场结构向寡占Ⅳ型发展.对比美国集装箱港口集中度发现,近10年来,我国集装箱港口集中度略高于美国,两国同属于寡占Ⅲ型的市场结构.但我国集装箱吞吐量是美国的3.59倍,我国前4位港口的平均集装箱吞吐量是美国的4倍,港口运输压力明显大于美国.过大的运输压力会给港口及其所在城市带来相应的负面影响.因此,在边缘挑战机制的作用下,我国沿海集装箱港口集中度有进一步下降的空间.     

中国煤炭产业集中度影响因素分析

在产业组织理论经典的SCP(结构-行为-绩效)分析范式中,市场结构通过影响市场行为,进而可以影响市场绩效.调整和改善不合理的市场结构是提高目标市场绩效的重要手段.产业集中度是重要的市场结构指标,它的变化的影响因素一直是产业经济学研究的重要内容.文章将产业组织理论和计量经济方法相结合,运用统计学相关方法及统计软件,对我国煤炭产业集中度的主要影响因素进行定量的实证分析,最终确立期初集中度、进入壁垒、市场容量、扩张能力等指标与煤炭产业集中度之间的数量关系,为制定我国煤炭产业又好又快发展的产业政策提供参考.     

边疆省区旅游经济系统脆弱性评价、影响因素及其应对策略——以云南省为例

以云南省16个市州为研究单元,运用综合指数法及障碍度模型探究2004-2016年云南省各市州旅游经济系统脆弱性的时空格局演变特征及其影响因素.结果表明:(1)2004-2016年云南省各市州旅游经济系统脆弱性总体呈下降趋势,其绝对差异与相对差异均呈波动下降态势;(2)旅游经济系统脆弱性空间分布格局日益均衡,高脆弱性市州空间集聚态势明显,"核心—边缘"式空间结构逐渐形成,低脆弱性市州呈现"趋同俱乐部"空间态势,边境市州脆弱性低于内陆市州;(3)云南省六大旅游区旅游经济系统脆弱性均呈下降趋势,其中以滇西北下降幅度最大,滇东北与滇东南下降幅度较小;(4)敏感性对旅游经济系统脆弱性发挥主导作用,其应对能力的主要制约因素是基础设施建设滞后与区域经济对外开放程度偏低.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with