Based on the materials of relevant strategies and research plans, this article analyzes the Arctic research related layouts of the United States, Russia, Canada and the five nordic countries. The characteristics of the Arctic strategies of these countries are summarized as follows:the United States, with its strong observation and research capabilities, plays an important role in the future research and development of the Arctic; Russia actively conducts research and deployment around territories and resources; Canada focuses on management and utilization of polar resources; the five nordic countries seek to stabilize and expand their Arctic interests. Finally, through comprehensive research and analysis, we put forward some suggestions for future Arctic research and cooperation.

Aeronautical materials' and products' demand for data, data resources sharing and data presenting style is analyzed from the perspectives of designing, planning, testing, applying and repairing department of industry and military, and discussed in the following aspects. 1) Systematic accumulation of environmental data, environmental effect data related to hotspot issues such as severe natural environment and induced environment, aeronautical microclimatic environment, operational environment, co-effect of environment and working condition, where environmental damaging rule, properties degradation rule, failure mechanism of the materials, coatings, component and products should be studied. 2) Establishment of a framework for environmental testing digital management and supporting scheme for data sharing & information exchange, so that an information platform is provided for environment testing application. 3) Reinforcement of analysis and secondary exploration of environmental testing data and acquirement of hidden knowledge. Finally, achievements from environmental testing should be engaged to the whole process of aeronautical products designing, manufacturing, application and maintenance, so that the technical mode route of "prediction-protection" can be realized.

This paper describes the application progress of American fifth-generation fighter's cockpit transparency technology. The US first three generations fighters' cockpit transparency front windshield uses the reinforced inorganic glass/film/inorganic glass reinforced material structure, the front side is curved plexiglass windshield, and the rear part of the plexiglass has bubble canopy, and it only provides bulletproof function of the pilot-field observation without any feature film. The US fourth-generation fighter cockpit transparency plexiglass uses pieces/film/polycarbonate material laminate structure, with early version using wear resistant functional coating and the latter version using stealth features film. The US fifth-generation fighter cockpit transparency uses polycarbonate structure and plexiglass pieces/polycarbonate material laminate structure, and uses stealth features film. Stealth technology is developing in the direction of all-weather, omni-direction, ultra-wide stealth frequency band, and intelligence. Future fighters will have ultra-wideband electromagnetic, infrared, acoustic, laser, video and other omni-directional super stealth performance. It is of great significance to learn from the failure and successful experience of the United States in the field of fightercockpit transparent parts. To study the cockpit transparent parts technology suitable for Chinese fighters will help to improve the overall technical level of Chinese fighters.

Residual stress, always existing in additive manufactured AlSi10Mg alloy, has negative effects on its application. Therefore, it is needed to be controlled or even eliminated by heat treatment. The microstructure, properties and residual stress of as built and annealed alloys are investigated using X ray diffraction, optical microscope, field emission scanning electron microscope, transmission electron microscope, electron backscattered diffraction, microhardness and Raman spectrum tests. The results show that as built alloy consists of supersaturated Al solid solution and Si phase. Additionally, the Si phase exists in the forms of cellular eutectic silicon and dispersed silicon nanoparticles. Meanwhile, the grain size of as built alloy is relatively fine, and the d₅₀ value of grain size distribution is about 10.4 μm. Annealing treatments lead to the depositions of alloying elements from supersaturated Al solid solution, and formations of equilibrium phase Mg₂Si and Si phase as the annealing temperature ranging from 250℃ to 300℃. With the increase of annealing temperature, the alloying elements precipitate out more thoroughly. Furthermore, the coarsening of cellular eutectic silicon and silicon nanoparticles, grain growth and recrystallization also occur owing to annealing treatment. Because of the decline of fine grain strengthening, solid solution strengthening and dispersion strengthening after annealing treatment, the microhardness decreases. The residual stress, however, can be significantly reduced by annealing process with a reduction of 60%~80%. Consequently, it is necessary to develop new heat treatment system according to the characteristic of additive manufactured aluminum alloy, in order to regulate and control the microstructure and properties.

To improve the fatigue performance of aircraft rotor of TB6 titanium alloy, the effects of laser shock peening (LSP), shot peening (SP) and their combination processing methods on surface integrity and axial fatigue property of the titanium alloy are investigated. The surface topography, residual stress distribution and microstructure are characterized by white light interferometer, X-ray diffraction stress tester and scanning electron microscope. The axial fatigue life and limit are investigated by fatigue tester. Results show that compared with the grinding (GD) specimen under the same test conditions, the fatigue life of LSP specimens is improved by 32.2 times, while the fatigue lifes of SP and the combination processing specimens are both increased by at least 126.4 times. The combination processing method exhibits better improvement for fatigue limit than the SP method.

Dehydrogenated curing fluorosilicone sealant is prepared at room temperature by mixing fluorosilicone liquid rubber, fumed silica, and metal oxide. Then heat resistance performance is investigated by thermal aging experiment at different temperatures (250 ℃ and 300 ℃). It is revealed that the heat resistance performance of rare earth metal oxide based fluorosilicone sealant is better than that of iron oxide at 250 ℃. However, when the temperature goes up to 300℃, the iron oxide based fluorosilicone sealant's heat resistance performance is better than the rare earth metal oxide's. Concerning the universality and economy of sealant, the iron oxide based fluorosilicone sealant possesses a wider application area.

Optical titanium dioxide film is deposited with the ion beam assistant twin magnetron MF reactive sputtering equipment. The variation of reactive plasma is monitored by Langmuir probe and the I-V curve is also tested simultaneously. The results demonstrate that the assistant ion beam plays an important role in enhancement of electrical charge density in the plasma region. With the increase of ion beam power assistance, the electron density increases and both minus floating potential and reactive sputtering voltage decrease. The plus potential on the surface of the substrate increases during the variation from electron-rich to ion-rich state. The substrate steps into the plasma electric neutrality state when the ion beam assistance power supply is 109 W.

Different from the phased array in which the beam direction is controlled by phase difference between array elements, the frequency diversity array (FDA) radar can realize beam control with higher degree of freedom by introducing frequency difference between array elements. This paper summarizes the research progress of FDA radar at home and abroad, and analyzes its current research status from aspects of array structure and orientation graphic coupling technology, electronic countermeasure technology application, electronic countermeasure technology application and so on. On this basis, some key technical problems to be solved, such as uncoupled FDA time-varying beam control, FDA-based electronic warfare technology and FDA-based radar practical research, are analyzed. For actual combat application of FDA, it is needed to develop a feasible time-invariant FDA distance-angle decoupling method of the beam and carry out integrated application research concerning FDA based structural analysis, launch waveform and frequency control function design, so as to speed up the process of FDA radar from conceptual stage to combat application.

By June 19, 2020, there had been 84940 COVID-19 confirmed cases in China, in which 83% of the clustered infections occurred within families. Thus, exploring the relative contributions of different transmission routes is significant for developing efficient intervention strategies in household. In this study, we build a mathematical model to quantify the relative degrees of importance of airborne, droplet and contact route in COVID-19 transmission in household environments. We find that the droplet and contact routes play the dominant role in COVID-19 transmission in household. Keeping a 1.5-2 m distance when communicating with the infector is the key intervention to control droplet transmission. Hand hygiene and surface cleaning are significant for controlling contact transmission. The infection risk by airborne route is relatively small, however, when the virus concentration in the droplets exhaled by the infector is high (possibly super-spreader), e. g. 107 mRNA copy/mL, the infection risk via the airborne route can be as high as 26%. This study may provide a theoretical guidance for developing targeted interventions in household environments.

Genome editing is the technology using sequence specific nucleases to modify the target genes of organisms. In recent years, genome editing technology represented by the CRISPR/Cas system has been rapidly developed due to its accurate, efficient and easy handling. Genome editing provides important tools for research of gene function, disease treatment and plant molecular breeding. At the same time, genome-edited products appeared in large numbers would have higher demands for the supervision of government departments. In this review, we summarize three types of genome editing technology and products. We also introduce regulations of some countries and economies in genome-edited plants and corresponding products. Several detection technologies for genome-edited plants and products are also introduced. This review can provide suggestions for supervision department of GM plant products and technical reserve for testing organizations.

Integrated service of "sector+meteorology" has played an important role in production, daily life, and various sectors of the society, and already gained outstanding achievements. By means of literature review, questionnaire survey, field visit, communications and discussions, a database of China's typical integrated service cases is established. Combining big data analysis and case study, this work constructs a framework of China's integrated service in terms of operational and administrative protocols, core content and procedure of integrated service. Meanwhile, it points out the existing problems of integrated service and proposes its development tendency in the new era. The core of the development of integrated services is to dig deeper industry demand for meteorological service and to promote vertical integration of meteorology and industrial chain. Then, multisector and cross-industry integration of core technologies is an important guarantee for the development of integrated services. Finally, for future reform direction, to develop "meteorology relevant" technology and product development closely integrated with industry and to adhere to refinement, individuation, diversification and wisdom of integrated services are highly concerned.

The long-short term memory model (LSTM) is a special recurrent neural network structure, which is widely used in system failure, traffic flow, stock index, emergency event, carbon emission, water table depth, and other fields, showing excellent prediction performance. This paper introduces the LSTM model into forecasting cultivated land area to enrich predicting methods and improve prediction accuracy. To verify the validity of the LSTM model in cultivated land area prediction, TE, GM, ES, ARIMA, SVM and NARNET models are selected for comparison, in which Heilongjiang, Jilin and Liaoning provinces are taken as case areas for revealing evaluation effects of different time series models. The results indicate that the prediction effect of LSTM is better than other models in terms of the comprehensive evaluation of RMSE and MAPE. Finally, according to LSTM forecast, the cultivated land areas of Heilongjiang, Jilin and Liaoning provinces will continue to decrease from 2018 to 2030 and the decrease rate will slow down.

Aimed at the requirements of central control and joint debugging and joint testing of warehouse intelligent prevention and control system under complex environment, an overall framework of the software system is presented. Using data flow and object-oriented methods, functional requirements of the software system are analyzed and the functional structure and network composition of the system are designed. Finally, corresponding software optimization suggestions are put forward.

Potassium is one of the three essential nutrients for crop growth. In 2020 the population of Asia reached 4.641 billion, accounting for 59.54% of the global population. Asia has long relied on importing potash fertilizer from Europe and the US. Thailand-Laos Mesozoic potash giant metallogenic belt has a predicted KCl prospect resource of more than 57 billion tons, of which Thailand's predicted KCl prospect resource is more than 43 billion tons. This article analyzes the Thailand's potash resource endowment, geography, infrastructure and other aspects, and believes that Thailand has the material condition for rapid development of a large potash base in Asia. With the in-depth development of the "Belt and Road", the promulgation of Thailand's new mineral law and the development of companies such as International Petroleum Corporation have shown the prospect for Thailand-Laos to establish a strategic potassium base in Asia. It is suggested that relevant countries and enterprises should plan to build a large-scale potash base in Thailand-Laos Asia as soon as possible, establish a large-scale potash base for Asia, and make contributions to the well-being of Asian people.

As a kind of weapon with super massive destructive power, genetic weapon can be miraculously effective in modern wars, but it also would be facing several dilemmas on war ethics. Military application of genetic weapons will threaten the civilian exemption, make the war an even more inhumane tool, make it difficult to control the aftermath of wars, and induce serious ecological disasters. In view of this, in the current era, human beings, as the subject of war, should strengthen the management and evaluation of gene technology, enhance moral restraints on and ethical awareness of scientists, and improve the supervisory and disciplinary mechanisms of genetic weapons, so as to effectively contain the research and use of genetic weapons and impose ethical constraints on modern wars.

From a perspective of history and philosophy of science, the study done by Chinese scholars on historical contributions of Francis Crick is interpreted in the paper. First of all, through literature research, the Chinese understanding and interpretation of Crick's scientific research achievements is revealed. A series of commemorative articles and DNA activities in science and technology museums reflect the academic community's memory of "Crick and Watson's intelligence contributions to humankind" and enhance Crick's recognition and popularity from the academic circle to the public's vision. It is pointed out that the Chinese versions of Crick's monographs, especially the translated versions of "Amazing Hypothesis", show the degree of Chinese scholars' preference for Crick's works, and the Crick's interactions with China demonstrate the cosmopolitan style of his scientific research.