Solution of the Nucleon Structure Problem from a Field Theory of Fermions and Bosons and the Origin of the Proton Stability

A bound state formalism derived from a fermion-boson symmetric Lagrangian has been used to calculate the nucleon masses, the charge neutrality of the neutron, the magnetic moments and the electromagnetic form factor ratios μpGEp/GMpand μnGEn/GMn. A quantitative description is obtained, assuming a mixing of a scalar bound state of 3(f f¯)fstructure with its corresponding vector (f f¯)fstate (f indicating massless elementary fermions). Only a few parameters are needed, mainly fixed by energy and momentum conservation. The nucleon stability is explained by an extra binding in the confinement potential, negative for electric and positive for magnetic binding of the proton, and opposite for the neutron. The stronger electric extra binding of the proton allows a decay of the neutron to proton and electron.

美国对华清洁能源产业竞争的态势与前景

With the development of global energy transition and carbon neutrality, the Biden administration attempts to enhance the economic competitiveness of the United States and its leadership in the field of international climate politics by promoting the development of clean energy industries such as solar photovoltaics, electric vehicles, and wind power generation. Toward this end, the Biden administration and the US Congress have increased support for the domestic clean energy industry through industrial policies and leveraged allied resources to achieve their agenda for this industry. A major target of the policies adopted by the Biden administration is competition with China. The approaches include politicizing the clean energy industry, linking investment access policies related to the clean energy industry with so-called national security considerations, and upgrading trade barriers against China. The competition orientation and policy measures of the US government in the field of clean energy industry will pose challenges to the international development of the clean energy industry in China. However, the US competition with China in the clean energy industry will be restricted due to domestic partisan politics and other factors. Thus, the potential exists for cooperation between China and the United States in the clean energy industry, which could create favorable conditions for the two countries to build a mutually beneficial cooperative relationship.

Supercritical carbon dioxide as a new working medium for pneumatic launch:A theoretical study

Compared with the conventionally gaseous or liquid working media,the specific internal energy of supercritical carbon dioxide(SCD)is higher at the same temperature and pressure,and the critical temperature of carbon dioxide is close to room temperature,making SCD a potential new working medium for pneumatic launch.To analyze the feasibility of this conception,an analytical model of a pneumatic catapult is established on basis of the conservations of mass and energy.The model consists of a high-pressure chamber and a low-pressure chamber connected by multiple valves,and there is a movable piston in the low-pressure chamber that can push an aircraft to accelerate.The effects of the launch readiness state of SCD in the high-pressure chamber,the initial volume of the low-pressure chamber and the valve control on the movement of the aircraft are analyzed.It is found that there is a restrictive relation between the temperature and pressure of the launch readiness state of SCD,i.e.,there is a maximum allowable launch readiness pressure when the launch readiness temperature is fixed.If this restrictive relation is not satisfied,the working medium in the low-pressure chamber will drop to its triple point within a few milliseconds,leading to a launch failure.Owing to this restrictive relation,there is an optimal launch readiness state of SCD with the highest working capacity for any allowable launch readiness temperature.The pressure of the low-pressure chamber will decrease significantly as the initial volume increases,leading to a decreased acceleration of the aircraft.The acceleration can be controlled below a critical value by a designed sequential blasting technique of multiple valves.The calculated results show that a 500 kg aircraft can be accelerated from 0 to 58 m/s in 0.9 s with 36 kg of carbon dioxide.This research provides a new technique for the controllable cold launch of an aircraft.

Critical Behavior of the Energy Gap and Its Relation with the Berry Phase Close to the Excited State Quantum Phase Transition in the Lipkin Model

In our previous work [Phys. Rev. A 85 （2012） 044102], we studied the Berry phase of the ground state and exited states in the Lipkin model. In this work, using the Hellmann-Feynman theorem, we derive the relation between the energy gap and the Berry phase closed to the excited state quantum phase transition （ESQPT） in the Lipkin model. It is found that the energy gap is approximately linearly dependent on the Berry phase being closed to the ESQPT for large N. As a result, the critical behavior of the energy gap is similar to that of the Berry phase. In addition, we also perform a semiclassical qualitative analysis about the critical behavior of the energy gap.

The Current State of China's Freshwater Resources and Related Suggestions

China has many lakes, marshlands and rivers. Due to their uneven geographical distribution and varied degrees of salinity, their exploitable freshwater resources are limited. In the wake of the highspeed growth of national economy in recent years, human infringement upon their natural settings has been increasingly intense, leading to the degeneration of China's lacustrine ecosystems and the degradation of their surrounding environments. Lakes are shrinking and becoming more saline. In arid and semi-arid inland areas, some of them have even disappeared. In addition, lake water pollution and eutrophication in densely populated areas are getting worse, resulting in serious water shortages in some places. Silt deposition in lake basins, water surface shrinkage caused by hectic and irrational reclamation for farmland, the prevalence of flooding and water-logging calamities and ecosystem depletion caused by predatory exploitation of fishery resources, all of these have become restrictive factors in regional sustainable development. The author of this article suggests measures for the protection and sustainable exploitation of limnetic settings in China.

A distributed approach for lidar-based relative state estimation of multi-UAV in GPS-denied environments

In this paper,we present a distributed framework for the lidar-based relative state estimator which achieves highly accurate,real-time trajectory estimation of multiple Unmanned Aerial Vehicles(UAVs)in GPS-denied environments.The system builds atop a factor graph,and only on-board sensors and computing power are utilized.Benefiting from the keyframe strategy,each UAV performs relative state estimation individually and broadcasts very partial information without exchanging raw data.The complete system runs in real-time and is evaluated with three experiments in different environments.Experimental results show that the proposed distributed approach offers comparable performance with a centralized method in terms of accuracy and real-time performance.The flight test demonstrates that the proposed relative state estimation framework is able to be used for aggressive flights over 5 m/s.

MOVING MOUNT China and the United States discuss bilateral relations and golbal issues during the first Strategic and Economic Dialogue

"Yes, we can was the mantra of the campaign that made Barack Obama the 44th President of the United States this year. Chinese State Councilor

China and the United States Should Build A New Type of Major Powers Relations——A Study on China’s U.S. Policy Thinking since the New Century

Since the reform and opening-up to the outside world, China has formed a series of guidelines and policies towards the United States, which are the theoretical foundation of China’s U.S. policy thinking in the New Century. Entering the new century, the international situation has undergone profound and complicated changes, the national strength gap between China and the United States has narrowed, their common interests have expanded, differences and contradictions have increased. Therefore, China stands for both countries to adhere to the direction of developing cooperative partnership, respect each other, abide by the promises, seek equal and mutual benefits and win-win cooperation, and mutually respect each others core interests. The future development of China-U.S. relations still face many challenges and China’s U.S. policy thinking needs to keep abreast with the times.

Geopolitics of the energy transition

Geopolitics of energy transition has increasingly become the frontier and hot research area of world energy geography and global political science.Different historical periods are characterised by obvious differences in energy connotations,attributes,and geopolitical characteristics.In the new energy era,energy geopolitics becomes more diversified,complex,and comprehensive.In this paper,we compare the geopolitical characteristics of energy in the fossil fuel and renewable energy periods,and provide an overview of current study trends in new energy geopolitics.Recent research shows that the global energy transition will intensify the reconstruction of geopolitical patterns,change the relationship between geopolitical security and conflict dominated by traditional energy security,alter the role of different countries in global energy geopolitical games,reshape national energy relationships formed in the traditional oil and gas era.In addition,geopolitics will be affected by new energy technologies,availability of key rare materials,and energy cybersecurity measures.Despite considerable attention to this research topic,the likely geopolitical impact of energy transition remains uncertain,and there is still room for the development and improvement of the theoretical framework,technical methods,and research perspective.Looking forward to the future,the research into geopolitics of energy transition urgently needs to strengthen its theoretical basis and rely on the scientific and quantitative methods.The practical conclusions of the research into geopolitics of energy transition should strengthen major national energy security decisions,explore the geographical effect of energy transition,and determine the impact of energy transition on energy security.Research into geopolitics of energy transition should be carried out taking into account international academic frontiers such as climate change,“carbon peak”and“carbon neutral”goals,and global energy governance,to enrich the research perspective of world energy geography.