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要素市场扭曲与企业出口产品质量——理论机制与实证检验
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作者 范爱军 郑志强 马永健 《产业经济评论(山东)》 2021年第4期119-143,共25页
通过合并匹配中国工业企业数据库、中国海关数据库和中国专利数据库,从理论和实证两个层面研究了要素市场扭曲对企业出口产品质量的影响及其作用机制。结果发现:要素市场扭曲显著抑制企业出口产品质量升级,使用工具变量法和变换代理变量... 通过合并匹配中国工业企业数据库、中国海关数据库和中国专利数据库,从理论和实证两个层面研究了要素市场扭曲对企业出口产品质量的影响及其作用机制。结果发现:要素市场扭曲显著抑制企业出口产品质量升级,使用工具变量法和变换代理变量后,结论依然成立;考虑企业特征、行业特征和地区特征的异质性分析结果表明,要素市场扭曲对一般贸易企业、民营企业、中西部企业的抑制作用更大,对资本密集型行业和劳动密集型行业的影响大于技术密集型行业;中介效应模型结果显示,企业生产率和固定成本投入效率是要素市场扭曲影响企业出口产品质量升级的重要途径。基于以上研究结论,本文提出完善要素市场资源配置机制、构建高质量生产体系以提高企业生产率和固定成本投入效率的政策建议。 展开更多
关键词 要素市场扭曲 出口产品质量 企业生产率 固定成本投入效率
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Global dynamics of a viral infection model with full logistic terms and antivirus treatments 被引量:1
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作者 Lijuan Song Cui Ma +2 位作者 Qiang Li aijun fan Kaifa Wang 《International Journal of Biomathematics》 2017年第1期209-232,共24页
In this paper, mathematical analysis of the global dynamics of a viral infection model in vivo is carried out. Though the model is originally to study hepatitis C virus (HCV) dynamics in patients with high baseline ... In this paper, mathematical analysis of the global dynamics of a viral infection model in vivo is carried out. Though the model is originally to study hepatitis C virus (HCV) dynamics in patients with high baseline viral loads or advanced liver disease, similar models still hold significance for other viral infection, such as hepatitis B virus (HBV) or human immunodeficiency virus (HIV) infection. By means of Volterra-type Lyapunov functions, we know that the basic reproduction number R0 is a sharp threshold para- meter for the outcomes of viral infections. If R0 ~ 1, the virus-free equilibrium is globally asymptotically stable. If R0 ~ 1, the system is uniformly persistent, the unique endemic equilibrium appears and is globally asymptotically stable under a sufficient condition. Other than that, for the global stability of the unique endemic equilibrium, another suffi- cient condition is obtained by Li-Muldowney global-stability criterion. Using numerical simulation techniques, we further find that sustained oscillations can exist and different maximum de novo hepatocyte influx rate can induce different global dynamics along with the change of overall drug effectiveness. Finally, some biological implications of our findings are given. 展开更多
关键词 Virus dynamics model Volterra-type Lyapunov function Li-Muldowneyglobal-stability criterion uniform persistence sustained oscillation.
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DYNAMICS BEHAVIOR OF MUTATION DURING REPRODUCTION ON HIV-1 DRUG RESISTANCE
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作者 GUANGYU HUANG aijun fan 《International Journal of Biomathematics》 2013年第3期109-120,共12页
To study the transition dynamics of resistant-type human immunodeficiency virus 1 (HIV-1) in highly active antiretroviral therapy (HAART) and the affect of neutral mutation in the evolution of HIV-1, a mathematica... To study the transition dynamics of resistant-type human immunodeficiency virus 1 (HIV-1) in highly active antiretroviral therapy (HAART) and the affect of neutral mutation in the evolution of HIV-1, a mathematical model is proposed when mutation occurs mainly during reproduction. The derived results show that the resistant-type will certainly colonize in patients once mutation occurs. Furthermore, a neutral mutation is closely related to the colonized pattern of resistant-type HIV-1 quasispecies and there are some changes in the pattern of transmission dynamics when mutation occurs mainly during reproduction or in the absence of reproduction, which may lead to significant strategies for predicting or checking HIV-1 drug resistance in HAART. 展开更多
关键词 Human immunodeficiency virus 1 mutation during reproduction drug resistance highly active antiretroviral therapy stability.
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