Liquid metal imbalance of the surface tension induces a pressure difference between the rear and the head, which produces a thrust to drive the droplet toward the head; at the same time, the hydrogen produced in the electrochemical reaction process also further raises the thrust. The discovery of this phenomenon laid the technical foundation for the development of intelligent motors, vascular robots, fluid pumping systems, flexible actuators and even more complex liquid metal robots. Liquid metal Liquid metal consists of alloys with very low melting points which form a eutectic that is liquid at room temperature. The standard metal used to be
Common external tariff economic integration. In addition to having the same customs duties, the countries may have other common trade policies, such as having the same quotas, preferences or other non-tariff trade regulations apply to all goods entering the area, regardless of which country, within the area, they are entering. Important examples of common external tariff are that of the Mercosur countries (Brazil, Argentina, Venezuela, Paraguay and Uruguay), the Common Customs Tariff of the Eurasian Economic Community customs union as well as the European Union Customs Union. Common external tariff A common external tariff must be introduced when a group of countries forms