基于多稳态柔性机构跨尺度微夹钳研究

为了解决传统微夹钳在夹持时存在精度较低、行程较小、不能跨尺度(um-mm)夹持物体的问题,提出了一种基于多稳态柔性机构跨尺度微夹钳结构。将多稳态结构与传统放大机构相结合,微夹钳左侧采用杠杆机构和平行四边形机构,右侧采用三个不同双稳态串联实现八稳态,最后由平行四边形机构保证微夹钳末端输出为单纯平行移动。首先,介绍微夹钳总体结构设计;接着,利用理论计算推导出了放大机构的位移放大比和多稳态特性;最后,运用有限元方法对模型进行分析,证实了微夹钳的性能及其安全性。该微夹钳有效夹持的位移范围大、放大倍率高、结构紧凑、能实现μm-mm的跨尺度平行夹持。     

Internet,Technological Innovation and High-Quality Economic Development

Using the panel data of 29 provinces in China from 2015 to 2018, this paper analyzes the impact of the internet, technological innovation, and their interaction on high-quality economic development. As the results show, the internet and technological innovation promote economic growth efficiency, economic growth stability, industrial structure optimization, and sustainable development level, where technological innovation promotes more significantly but hinders the economic welfare level to some extent; the interaction between the internet and technological innovation has a significant positive correlation with high-quality economic development and strengthens the promotion of technological innovation on high-quality economic development; human capital plays a significant role in promoting all aspects of high-quality economic development, while fiscal expenditure has no significant impact on high-quality economic development. Therefore, the internet should be leveraged to drive technological innovation capacity, and better play the guiding role of the government.     

“同治”还是“同谋”:机构投资者抱团与 企业违约风险

文章以2009—2020年沪深A股非金融上市公司为研究样本,实证检验了机构投资者抱团对企业违约风险的影响及其内在机理。研究发现,机构投资者抱团可以降低企业违约风险。影响机理的检验证实,机构投资者抱团通过降低信息不对称、缓解融资约束和降低经营风险对企业违约风险产生影响。进一步从信息、资源和风险的视角探讨两者关系的异质性发现,机构投资者抱团对企业违约风险的治理效应主要体现在信息不对称程度较高、资源获取较难和风险较高的样本中。文章的发现有助于深化机构投资者抱团的经济后果与企业违约风险影响因素的研究,也为进一步完善机构投资者的制度设计、持续优化公司的内外部治理结构,防范化解企业违约风险提供了参考依据。     

土地资源空间错配的绿色全要素生产率损失效应与作用机制

研究目的：刻画、分析土地资源空间错配对绿色全要素生产率的影响及其作用机制，指出缓解土地资源空间错配促进绿色全要素生产率提升的路径。研究方法：面板中介效应模型。研究结果：（1）土地资源空间错配的绿色全要素生产率损失效应显著存在，土地供给相对短缺城市的损失效应明显大于土地供给相对过剩城市。（2）结构效应、技术效应、规模效应三个维度的作用机制都显著成立。（3）对于全部城市，结构效应、技术效应相当，规模效应相对次要；对于土地供给相对过剩城市，结构效应更为重要；对于土地供给相对短缺城市，技术效应更为重要。研究结论：减缓土地资源空间错配程度，并分别针对性地避免制造业低端锁定效应、创新能力削弱效应在中西部、东部城市的负面作用，有利于提升绿色全要素生产率。     

Cross-border regulatory enforcement and corporate voluntary disclosure

In this study, we find that foreign firms cross-listed in the US issue significantly more and better-quality management earnings forecasts after their home countries sign the Multilateral Memorandum of Understanding Concerning Consultation and Cooperation and the Exchange of Information (MMoU), a nonbinding arrangement established by the International Organization of Securities Commissions to enhance the cross-border enforcement of securities laws. Specifically, we find that after the MMoU, relative to their domestic counterparts in the US, foreign firms cross-listed in the US are not only more likely to issue management earnings forecasts but also issue them more frequently. They also tend to issue better-quality earnings forecasts, as measured by lower surprise, higher precision, greater timeliness, more disaggregation, lower optimism and fewer errors. We find that the observed effects of the MMoU signing are stronger for cross-listed firms from countries with weaker institutional environments, resulting in greater enforcement concerns after the MMoU, and for firms with less foreign institutional ownership before the MMoU. Collectively, our findings support the conjecture that after a US-listed foreign firm's home country enters the MMoU, the firm has more incentives to engage in voluntary disclosure due to greater concerns about regulatory enforcement and increased information demand from investors.     

Search less for a better price

In many markets, sellers must spend resources to learn the costs of providing goods/services. This paper considers consumer searches in such markets. The findings show that: (i) even with ex ante identical consumers and sellers, there is price dispersion in the equilibrium, (ii) despite price dispersion and minimal search costs, it could be optimal to search just two sellers and (iii) the optimal number of searches can increase with sellers' information costs.     

Identifying critical success factors for the agri-food cold chain's sustainable development: When the strategy system comes into play

With serious environmental, cost, and social concerns arising from emerging countries' rapid growth in agricultural food cold chain (AFCC), AFCC firms urgently require a set of comprehensive sustainable strategic solutions. Therefore, this research identified and modeled the critical success factors (CSFs) that support the sustainable development of AFCCs. The study integrated institutional theory, stakeholder theory, and the triple bottom line model; it also surveyed cold chain experts from 16 different organizations in China and applied the adversarial interpretation structure model (AISM). This comprehensive analysis indicates that managing stakeholder pressure is the most motivating CSF of all strategies. This strategy eventually contributes to the sustainability of AFCC in China by driving other CSFs. Additionally, the study determined the degree of interdependence and dominance of different strategies. Thus, this study establishes a theoretical foundation for the sustainable improvement of AFCC organizations' business strategies and environmental policies.     

地方政府“两手”供地策略对产业结构优化的非线性影响——基于合理化与高级化双重视角的考察

研究目的：利用276个地级市2007—2020年的面板数据，分析不同经济发展阶段内，地方政府“两手”供地策略对产业结构合理化、高级化的差别化影响，为调整土地供给策略，推动产业结构优化提供相应的政策启示。研究方法：面板门槛模型。研究结果：（1）对于产业结构合理化，以25 438.02元（2007年价）的人均GDP为门槛，将城市经济发展水平划分为低、高两个阶段，两阶段内地方政府“两手”供地策略对产业结构合理化分别表现为积极与消极影响，消极影响的大小为积极影响的1.78倍。（2）对于产业结构高级化，以23 694.54元（2007年价）的人均GDP为门槛，将城市经济发展水平划分为低、高两个阶段，两阶段内地方政府“两手”供地策略对产业结构高级化分别表现为积极与消极影响，两者大小基本一致。（3）全国层面上，地方政府“两手”供地策略对产业结构合理化与高级化差别化影响的转变出现在2010—2011年间；城市层面上，多数城市积极影响已经转变为消极影响。研究结论：地方政府“两手”供地策略对产业结构合理化、高级化的差别化影响具有同步、同方向的“双同”特征，有序地推进 “两手”供地策略的市场化转型，可以最大程度获取积极影响并避免其消极影响。