垂直一体化对企业创新的非线性影响

本文以2000-2012年A股主板制造业上市公司为研究对象,使用价值增值法测算垂直一体化程度,并利用专利引用来衡量企业创新产出,实证分析了垂直一体化对企业创新的影响及其异质性。研究发现,垂直一体化与企业创新之间的关系呈倒U型,即存在先正后负的现象。进一步,该倒U型关系在高科技企业以及非国有企业中更为显著。并且,该倒U型关系仅存在于东部和中部地区。本文对企业合理选择组织边界以及政府制定相关政策均具有参考价值。     

Simman模拟人在心肺复苏临床技能教学中的调查研究

目的:探讨Simman模拟人在心肺复苏技能教学中的应用效果。方法:60名临床医学专业学生参加CPR操作培训,实际操作练习,并对所有学生进行匿名问卷调查,分析Simman模拟人系统在心肺复苏技能教学中的应用效果。结果:90%以上的学生认为Simman模拟人模拟真实,重复性强,89%的学生认为Simman模拟人能充分调动学习积极性,88%的学生认为Simman模拟人操作性强,非常认同Simman模拟人出科考核模式。95%的学生认为Simman模拟人能够全面考核学生的临床思维,91%的学生认为Simman模拟人能够进一步巩固和提高学生的理论知识。结论:Simman模拟人系统在心肺复苏技能实践教学中能明显提高临床技能教学的质量。     

Paving the road toward the use of β-Fe2O3 in solar water splitting: Raman identification,phase transformation and strategies for phase stabilization

Although β-Fe₂O₃ has a high theoretical solar-to-hydrogen efficiency because of its narrow band gap, the study of β-Fe₂O₃ photoanodes for water splitting is elusive as a result of their metastable nature. Raman identification of β-Fe₂O₃ is theoretically and experimentally investigated in this study for the first time, thus clarifying the debate about its Raman spectrum in the literature. Phase transformation of β-Fe₂O₃ to α-Fe₂O₃ was found to potentially take place under laser and electron irradiation as well as annealing. Herein, phase transformation of β-Fe₂O₃ to α-Fe₂O₃ was inhibited by introduction of Zr doping, and β-Fe₂O₃ was found to withstand a higher annealing temperature without any phase transformation. The solar water splitting photocurrent of the Zr-doped β-Fe₂O₃ photoanode was increased by 500% compared to that of the pure β-Fe₂O₃ photoanode. Additionally, Zr-doped β-Fe₂O₃ exhibited very good stability during the process of solar water splitting. These results indicate that by improving its thermal stability, metastable β-Fe₂O₃ film is a promising photoanode for solar water splitting.     

A stage-specific cell-manipulation platform for inducing endothelialization on demand

Endothelialization is of great significance for vascular remodeling, as well as for the success of implanted vascular grafts/stents in cardiovascular disease treatment. However, desirable endothelialization on synthetic biomaterials remains greatly challenging owing to extreme difficulty in offering dynamic guidance on endothelial cell (EC) functions resembling the native extracellular matrix-mediated effects. Here, we demonstrate a bilayer platform with near-infrared-triggered transformable topographies, which can alter the geometries and functions of human ECs by tunable topographical cues in a remote-controlled manner, yet cause no damage to the cell viability. The migration and the adhesion/spreading of human ECs are respectively promoted by the temporary anisotropic and permanent isotropic topographies of the platform in turn, which appropriately meet the requirements of stage-specific EC manipulation for endothelialization. In addition to the potential of promoting the development of a new generation of vascular grafts/stents enabling rapid endothelialization, this stage-specific cell-manipulation platform also holds promise in various biomedical fields, since the needs for stepwise control over different cell functions are common in wound healing and various tissue-regeneration processes.     

Experiments on Cu-isotope fractionation between chlorine-bearing fluid and silicate magma: implications for fluid exsolution and porphyry Cu deposits

Hydrothermal fluid is essential for transporting metals in the crust and mantle. To explore the potential of Cu isotopes as a tracer of hydrothermal-fluid activity, Cu-isotope fractionation factors between Cl-bearing aqueous fluids and silicate magmas (andesite, dacite, rhyolite dacite, rhyolite and haplogranite) were experimentally calibrated. Fluids containing 1.75–14 wt.% Cl were mixed together with rock powders in Au₉₅Cu₅ alloy capsules, which were equilibrated in cold-seal pressure vessels for 5–13 days at 800–850°C and 2 kbar. The elemental and Cu-isotopic compositions of the recovered aqueous fluid and solid phases were analyzed by (LA-) ICP–MS and multi-collector inductively coupled plasma mass spectrometry, respectively. Our experimental results show that the fluid phases are consistently enriched in heavy Cu isotope (⁶⁵Cu) relative to the coexisting silicates. The Cu-isotope fractionation factor (Δ⁶⁵Cu_FLUID-MELT) ranges from 0.08 ± 0.01‰ to 0.69 ± 0.02‰. The experimental results show that the Cu-isotopic fractionation factors between aqueous fluids and silicates strongly depend on the Cu speciation in the fluids (e.g. CuCl(H₂O), CuCl₂^– and CuCl₃²⁻) and silicate melts (CuO_1/2), suggesting that the exsolved fluids may have higher δ⁶⁵Cu than the residual magmas. Our results suggest the elevated δ⁶⁵Cu values in Cu-enriched rocks could be produced by addition of aqueous fluids exsolved from magmas. Together with previous studies on Cu isotopes in the brine and vapor phases of porphyry deposits, our results are helpful for better understanding Cu-mineralization processes.     

漫话藏书票

藏书票是表明藏书持有者的标志,是人们读书、爱书、藏书的信物,它既有装饰图书的实用功能,又有艺术欣赏价值、历史研究价值。介绍了藏书票的形制、内容及在我国的传播。     

北京民办高校发展的现状与特点

本文对目前北京民办高校发展的数量与规模进行了介绍,并对其发展特点、作用、基本经验及改革措施等几个方面进行了分析。     

数字信号处理教学改革与实践探索

本文结合“数字信号处理”这门课程的特点,为使传统的课堂型教学逐渐过渡到探索型教学,从教学内容、教学方法以及教学实践等方面进行了实践和探讨。     

壶关地区的『祭星』习俗

春节是我国最重要的岁时节日之一。春节期间,各地有不同的民俗活动。在笔者生活的晋东南壶关地区的农村,每年正月初八,家庭主妇都要在自家庭院举行“祭星”仪式。有关这一习俗,清潘荣陛的《帝京岁时纪胜》记载。