中国OFDI对“一带一路”国家GTFP的门槛效应研究

在可持续发展的背景中,以资源节约、环境友好为导向的绿色发展备受世界各国关注。提高绿色全要素生产率（GTFP）成为了绿色发展的重点。GTFP不仅体现了经济增长的效率,同时将资源消耗与环境污染囊括其中。在“一带一路”建设的过程中,中国对沿线国家的投资力度不断增加。为探索中国对外直接投资（OFDI）对“一带一路”东道国GTFP的作用,在考虑到中国与东道国政治制度环境和经济制度环境差异的前提下,本文运用面板门槛模型分析中国OFDI对东道国GTFP的门槛效应。实证结果表明中国OFDI能够对“一带一路”东道国GTFP产生正向作用,然而这种正向作用受到政治制度距离和经济制度距离的制约,随着制度距离的增大,中国OFDI对东道国GTFP的正向作用减弱。具体来说：1）当政治制度距离低于1.986时,中国OFDI对东道国GTFP的回归系数为0.072;当政治制度距离处于1.986至2.513之间时,回归系数为0.058;当政治制度距离大于2513时,回归系数为0.012。2）当经济制度距离低于1.440时,中国OFDI对东道国GTFP的回归系数为0.102;当经济制度距离处于1.440至2.575之间时,回归系数为0.085;当经济制度距离大于2.575时,回归系数为0.023。3）扩大对外直接投资规模能够减少双边制度差异带来的影响,提升中国OFDI对东道国GTFP的正向作用,随着对外直接投资规模由3.899提升至4.15,中国OFDI对东道国GTFP的正向作用由0.028增至0.122。     

中国与“一带一路”沿线国家农产品贸易的虚拟水流动研究

随着商品贸易,商品中所隐含的虚拟水也随之发生了转移。基于中国与“一带一路”沿线国家农产品贸易数据,测算2001、2007、2013、及2019年农产品贸易虚拟水量,分析中国与“一带一路”沿线地区虚拟水流动格局,通过位序-规模法及分形理论对各伙伴国贸易规模及空间分布发展进行研究以此来探究其垄断性及依赖性。结果表明：2001—2019年期间中国净进口“一带一路”沿线国家虚拟水量由83亿m3增至875亿m3,净出口国家数量由7个增加至27个,空间分布向均衡发展,位居前列的国家对中国的垄断性有所减弱;净出口量由33亿m3增至45亿m3,净进口国家数量由58个减少到47个,空间分布向集中发展,位居前列的国家对中国的依赖性增强;中国净进口的虚拟水类型以绿水为主,平均每年占比85.93%,主要来自于东南亚、南亚和东欧等地区;中国净出口的虚拟水类型以绿水和灰水为主,平均每年占比65.03%和24.07%,主要出口至非洲、西亚等地区;南亚、东欧、中亚、非洲及南欧由净进口区转变为净出口区;东亚仍为净进口地区。     

基于“两个细则”的一次调频影响因素分析与对策研究

并网机组的一次调频功能对于电网的稳定性来说至关重要。随着“两个细则”的发布,电网对一次调频功能的考核越来越严格。在此背景下,本文总结了影响一次调频的11个因素并给出了相应的解决措施,具有一定的借鉴意义。     

Premixed hydrogen-air flame front dynamics in channels with central and peripheral ignition

Experimental and analytical study of burning hydrogen-air mixtures with 12, 13, and 15 vol% hydrogen concentrations in channels with central and peripheral ignition was performed. Flame propagation speeds were determined by shadow and infrared high-speed imaging in the transverse and longitudinal directions, respectively. It was found that the increase in the flame front speed during the peripheral ignition reaches up to 1.7 times compared to the central ignition depending on mixture content. The pressure growth rate was examined in a closed channel. It was estimated that the time to reach a maximum pressure is 1.1 times less in the case or peripheral ignition than the central one. An analytical model was formed to describe the dynamics of the flame front in both cases. The model of a “reversed finger-flame” generated by a peripheral ignition was presented. The obtained results could be used in designing hydrogen-fueled combustible engines with the reduced knock-effect.     

Electromagnetic transients in the control system of output parameters of a solar power plant in Tajikistan Central Asia region

At present, as the demand for electricity increases in all sectors, there is an urgent need to introduce alternative renewable energy sources into modern energy systems. Renewable energy sources, which consist of solar (photovoltaic, PV), wind and hydro power, are key alternative sources of “green energy’’ energies, but it can also be used to produce “green” hydrogen. Thanks to scientific and technological progress, the cost of photovoltaic solar radiation converters is constantly decreasing at a high rate, which makes it possible to build solar power plants of sufficiently large capacity. In the coming decades, solar energy will become an incentive for the economic development of countries that have the maximum “solar” resource. The Republic of Tajikistan is one of these countries with a high potential for solar energy.The article presents an analysis of the resources and potential of solar energy in the Republic of Tajikistan. The study of electromagnetic transients in networks with photovoltaic solar power plants is performed. The main equations, simulation model and calculations of transients are presented, taking into account changes in voltage on DC buses. An algorithm for controlling the system of automatic control of output parameters is proposed. The analysis of dynamic and static modes in parallel operation of a solar power plant with the grid is carried out. A block diagram and computer model is constructed in the MATLAB package together with Simulink and Power System Blockset.     

Asymmetric “Janus” Biogel for Human-Machine Interfaces

Human-machine interfaces (HMIs) are essential for effective communication between machines and tissues. However, mechanical and biological mismatches, along with weak adhesion between rigid electronic devices and soft tissue, often cause unreliable responses and affect the signal recording of HMIs. In this study, an asymmetrical “Janus” biogel patch with one side firmly adhering to tissues, and the other surface having little adhesion and minimal interactions with surrounding environments has been developed. A series of analytical, mechanical, and electrical tests are performed to investigate the “Janus” biogel patch as a functional and biocompatible HMI. It is found that the gallic acid-modified gelatin adhesive surface on one side exhibits body temperature-dependent tissue adhesion, enabling low modulus and seamless skin contact. The other side is a tough gelatin/glycerol gel layer, which is thermally welded into the adhesive layer and functions as an encapsulant to prevent external interference due to adhesion. The encapsulation layer also exhibits a low friction coefficient when wet and proves to be a reliable alternative barrier to conventional encapsulation materials. The scientific insights and engineering principles revealed in this type of “Janus” biogel will be applicable to a broad range of biomedical applications, such as epidermal adhesive electrodes or skin-adhesive wearable devices.     

基于“微生物-肠-脑”轴的肠道菌群参与抑郁症相关研究进展

抑郁症是现代社会较为普遍的精神障碍类疾病之一。抑郁症不仅严重危害人们的生活质量,还因为其高自杀率及致残率给家庭和社会带来巨大负担。近年来国内外的研究表明,肠道菌群在抑郁症的发生和发展中扮演着重要角色,肠-脑通信功能紊乱可能是抑郁症的重要病理机制,“微生物-肠-脑”轴是肠道菌群参与的肠道和大脑双向信息交流的通道。目前相关研究主要集中在抑郁症个体菌群特征和肠道菌群与抑郁症发病关系的探索方面,提示维护健康的肠道菌群可能是抑郁症预防和治疗的新思路。本文对相关方面的研究进展进行总结,以期从“微生物-肠-脑”轴角度为抗抑郁活性物质作用机理研究提供深入解释,也为益生菌在新的抑郁症治疗手段方面的应用提供参考与借鉴。     

Source Choice Perception and Sustainable Rural Water Supply Development: A Case Study of Ban Thadindam,Lopburi, Thailand

Abstract

This study seeks to examine source choice perception and sustainable rural water supply development in Ban Thadindam, a Thai village situated about 220 km north of Bangkok. It makes use of an elementary schematic matrix that was initially developed for the valuation of water sources as perceived by water users in East Africa. In applying the elementary choice scheme, the author interviewed the village Kamnan (district officer) and a few villagers. The results of this study show that a wide range of water supply sources was perceived by the Kamnan. Out of a practical range of six sources, four were perceived and accepted, roof (rain water), river, spring, and pond; and two were perceived but not accepted: well and canal. The reason why well and canal water sources were rejected was because of their hardness and turbidity. Of the four sources accepted, roof (rain water) was rated very favorably as the preferred choice while river, spring, and pond sources were judged equally favorable. Awareness of source choice and the conditions under which choice is made is crucial for the understanding and development of sustainable rural water supply. By adopting a wide combination of sources and integrating them to provide a rich water supply for treatment, and by taking advantage of filtration technology given by the Asian Institute of Technology, Environmental Engineering Division, the villagers, with the help of the Project Managing Committee, transformed the demonstration filtration facility into a sustainable rural water supply system. The latter succeeded not only in providing adequate filtered water for the majority of the households in Ban Thadindam but also in satisfying the water requirements for the whole village for two decades. The success of the rural water supply system has been attributable to many factors, but most important was the awareness the villagers have in the understanding of the interrelations between landscape, range of choice and the interaction between community participation, technology, and environment.