数字经济、人力资本流动与企业自主创新——基于中国创新调查企业的证据

本文选取2011—2014年全国创新调查企业数据,基于人力资本流动视角,考察了数字经济对制造业企业自主创新的影响。研究发现,数字经济发展能够有效推动企业自主创新。其中,数字经济通过引发人力资本流动,提升了硕士及以上学历员工、技术员工在企业内部的占比,是推动企业自主创新的重要途径,但这种机制可能会强化中国“西低东高”的区域创新格局,并进一步拉大制造业内部创新差距,形成以“熊彼特效应”占优为主导的产业结构。此外,数字经济发展对企业自主创新的影响在处于不同市场化水平和政务化水平的分位区间内表现出显著差异性。

“结构-行为-绩效”范式的动态演化与研究进展

20世纪50年代开始的市场“结构-行为-绩效”研究从“势力说”与“效率说”的争论到如今多维度的实证分析已历经60余年,计量经济学的方法创新使原有范式的实证结果更加精确,并衍生加入了经济周期、行业周期等动态变量.此外,新近理论进展主要体现为两大方面的演化,一是方法论的演进,博弈论的介入增加了原范式的理论逻辑性,使市场行为更多体现为企业策略行为,而产业模块化的分析改变了原有范式的微观基础;二是在新经济背景下,政府规制和经济全球化的影响使原有研究范式的宏观环境有所变化,结构有所拓展.通过梳理目前结构-行为-绩效研究范式的动态演化和最新进展,可以为未来的产业组织研究提供更加完整的理论视角和实证方针.

要素替代、有偏技术进步与中国火电产业升级

火力发电产业升级的关键是依托技术进步实现资本对能源的替代。在CD生产函数框架下，本文研究火电产业通过有偏技术进步实施要素替代，从而实现产业升级的可行性。基于中国火电产业2000—2015年数据，本文估计了包含有偏技术进步的超越对数成本函数，以计算要素问的MES、AES替代弹性，进而估算出技术进步的偏向性。结果表明，中国火电行业的资本与能源呈现替代关系，且技术进步能够节约能源。因此，必须促进对研发、技术改造和引进先进机组、环保设备的投入，以减少能源消耗。

Broad temperature adaptability of vanadium redox flow battery-part4:Unraveling wide temperature promotion mechanism of bismuth for V^(2+)/V^(3+) couple

Vanadium flow battery （VFB） is a fast going and promising system for large-scale stationary energy stor- age. However, drawbacks such as low power density and narrow temperature window caused by poor catalytic activity of graphite felt （GF） electrodes limit its worldwide application. In this paper, bismuth, as a low-cost, no-toxic and high-activity electrocatalyst, is used to modify the thermal activated GF （TGF） via a facile hydrothermal method. Bismuth can effectively inhibit the side reaction of hydrogen evolution in wide temperature range, while promoting the V2＋/V3＋ redox reaction. As a result, the VFB assembled with Bi/TGF as negative electrode demonstrates outstanding rate performance under the current density up to 400 mAcm-2, as well as a long-term stability over 600 charging/discharging cycles at a high cur- rent density of 150mA cm-2. Moreover, it also shows excellent temperature adaptability from -10 ℃ to 50 ℃ and high durability for life test at the temperature of 50 ℃.

P-doped electrode for vanadium flow battery with high-rate capability and all-climate adaptability

A phosphorous-doped graphite felt(PGF) is fabricated and examined as electrode for vanadium flow battery(VFB). P doping improves the electrolyte wettability of GF and induces more defect sites on its surface, resulting in significantly enhanced activity and reversibility towards VO2^+/VO2^+ and V^2+/V3^+couples. VFB with PGF electrode demonstrates outstanding performance such as high-rate capability under 50–400 mA cm^-2, wide-temperature tolerance at-20 °C–60 °C, and excellent durability over 1000 charge–discharge cycles. These merits enable PGF a promising electrode for the next-generation VFB,which can operate at high-power and all-climate conditions.

ZIF-derived holey electrode with enhanced mass transfer and N-rich catalytic sites for high-power and long-life vanadium flow batteries

Electrode materials with good redox kinetics,excellent mass transfer characteristics and ultra-high stability play a crucial role in reducing the life-cycle cost and prolonging the maintenance-free time of the vanadium flow batteries(VFB).Herein,a nitrogen-doped porous graphite felt electrode(N-PGF)is proposed by growing ZIF-67 nanoparticles on carbon fibers and then calcinating and acid etching.The multi-scale structure of“carbon fiber gap(electrolyte flow),micro/nano pore(active species diffusion)and Nitrogen active center(reaction site)”in N-PGF electrode effectively increases the catalytic sites and promotes mass transfer characteristics.Reasonable electrode design makes the battery show excellent rate performance and ultra-high cycling stability.The peak power density of the battery reaches 1006 mW cm^(-2).During 1000 cycles at 150 mA cm^(-2),the average discharge capacity and average discharge energy of N-PGF increase substantially by 11.6%and 23.4%compared with the benchmark thermal activated graphite felt,respectively.More excitingly,after ultra-long term(5000 cycles)operation at an ultra-high current density(300 mA cm^(-2)),N-PGF exhibits an unprecedented energy efficiency retention(99.79%)and electrochemical performance stability.

Application Effects of Stabilized Fertilizer with Reduced Amount and Frequency on Rice

The activity of microorganisms in the soil can be adjusted through the application of stabilized fertilizer.Using biochemical means,the transformation of nitrogen in the soil is controlled,synchronizing the peak of nutrient released from soil and the peak of nutrient absorption by rice.With the application of stabilized fertilizer,the fertilizer utilization rate and the income of farmers can be improved and the environmental pollution can be cut down by reducing the amount of nitrogen fertilizer and decreasing the frequency of fertilization.This paper summarizes the application effects of stabilized fertilizer on different cultivars of rice in different regions for many years,and puts forward the issues to be concerned in the application of stabilized fertilizer with reduced amount and frequency and efficiency improvement techniques.