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原始性创新的外部效应及其控制 总被引:6,自引:2,他引:6
本文在分析原始性创新外部性的性质特征及正、负外部性效应的基础上,提出原始性创新应分门别类分别由国家或企业主导实施,并深入探讨了正外部效应的补偿激励措施和负外部效应的解决途径。 相似文献
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论述了原生资源的概念,分析了高校原生信息资源的特点与类型,以及原生文献从收集、验收登记到加工利用的一些浅见,并对其今后的发展趋势做了简短评述。 相似文献
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介绍了马普学会、弗朗霍夫学会、赫尔姆霍兹协会、莱布尼茨协会等德国科研机构采用同行评议方法评价研究所的实践与经验,探讨了对我院开展研究所综合质量评估的启示。 相似文献
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A modified theory is proposed for extracting cell dielectric properties from the peak frequency measurement of electrorotation (ER) and the crossover frequency measurement of dielectrophoresis (DEP). Current theory in the literature is based on the low frequency (DC) approximations for the equivalent cell permittivity and conductivity, which are valid when the measurements are performed in a medium with conductivity less than 1 mS/m. The present theory extracts the cell properties through optimizing an expression for the medium conductivity in terms of the peak ER, or DEP crossover, frequency according to its definition using full expressions of equivalent cell permittivity and conductivity. Various levels of approximation of the theory are proposed and discussed through a scaling analysis. The present theory can extract both membrane and interior properties from the low and the high peak ER, or DEP crossover, frequencies for any medium conductivity provided the peak ER, or DEP crossover, frequency exists. It can be reduced to the linear theory for the low peak ER and DEP crossover frequencies in the literature when the medium conductivity is less than 10 mS/m. However, we can determine the membrane capacitance and conductance via the slope and intercept, respectively, of the straight line fitting of the ER peak and DEP frequency against medium conductivity data according to the linear theory only when the intercept dominates the experimental uncertainty, which occurs when the medium conductivity is less than 1 mS/m in practice. 相似文献
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基于选择实验法的胶州湾湿地围垦生态效益损失评估 总被引:2,自引:0,他引:2
选择实验法是当前国际上用于评估资源环境价值的前沿方法。本文针对胶州湾湿地围垦生态影响,应用选择实验法,评估湿地围垦造成的生态效益损失,提出生态修复优选方案。在查阅文献和咨询专家的基础上,确定了湿地面积、植被覆盖率、湿地水质和生物多样性4项湿地修复属性。通过对胶州湾地区293名居民进行随机抽样调查,定量评估了湿地修复中不同属性的支付意愿价值,评估结果显示:若将湿地的各项属性修复至基线水平,居民的支付意愿约为321.78元/(年·户),据此测算胶州湾湿地围垦的生态效益损失约为7.67亿元/年。研究结果进一步表明:4个属性中居民对湿地面积变化的关注程度最高,其次是湿地水质,因此政府应当制定以恢复湿地面积为重点的湿地保护和修复政策。 相似文献
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以松脂为原料,酸改性膨润土为催化剂进行松脂直接歧化-裂解制备对伞花烃和松脂基生物柴油的研究。采用三因素四水平正交实验考察了反应温度、催化剂用量(以原料质量分数计)和反应时间对对伞花烃得率和松脂基生物柴油酸值的影响。实验结果表明,反应的优化条件为:反应温度260℃、催化剂用量为10%和反应时间120 min,对伞花烃的得率为47.9897%和松脂基生物柴油酸值为0.46 mgKOH·g-1,反应温度和催化剂用量对产品的收率和品质影响较为显著。松脂基生物柴油与O#柴油调和后低温流动性得到明显改善。 相似文献