In the context of climate change, increases in extreme weather have caused a series of problems, severely reduced crop yield, and caused a loss of agricultural cultivation. In addition, because of the high economic benefits, continuous cropping has become more popular but it leads to higher land-use intensity in production systems, aggravating the problems of extreme climate and seriously influencing China’s agricultural production and ecological environment. From this, the importance of improvements to cropping systems’ resilience to climate change is now much clearer than before. Crop rotation is an important tool for improving the climate resilience of the agricultural production system and effectively solving the shortcomings of the current continuous crop methodology. Crop rotation is indispensable in many national strategies, including food security, ecological environment development, and rural revitalization. This study aimed to promote the improvement of the crop rotation system in China and aimed to play a significant role in guiding China towards the large-scale development of crop rotation. This literature review shows that crop rotation can effectively enhance climate resilience and reduce the fragility of agricultural cropping systems. It then delves into the origin and development of crop rotation, and summarizes the characteristics of crop rotation. In view of the neglect of ecological benefits in China’s agricultural development, this article puts forward three suggestions: first, developing crop rotation technology based on local conditions; second, paying attention to the ecological benefits of crop rotation subsidies, followed by implementing appropriate and flexible subsidy policies; and, finally, carrying out rational evaluations and policy adjustment of crop rotation practices.

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Previous studies on orbital angular momentum (OAM) communication mainly considered line-of-sight environments. In this letter, however, it is found that OAM communication with high-order modulation can be achieved in highly reverberant environments by combining the OAM multiplexing with a spatial equalizer. The OAM multiplexing exhibits comparable performance of conventional multiple-input multiple-output (MIMO) system. Index Terms-Multiplexing, orbital angular momentum (OAM), reverberant environment

Students at the Rowan University department of Mechanical Engineering have been assigned a long-term, large-scale design/build project in order to study the effects of integrating the curriculum on subject matter retention and design efficacy. The project, a bench-scale hybrid electric powertrain system, is designed, analyzed and fabricated by students in six modules, starting in their sophomore year and culminating in their final semester as seniors. This complex project has been selected in order to integrate the core mechanical engineering courses: Mechanical Design, Thermodynamics, System Dynamics and Control, and Fluid Mechanics. A bench-scale hybrid-electric vehicle powertrain has sufficient complexity to involve all Mechanical Engineering disciplines and the simplicity to be built by students over the course of five semesters. The research is designed to test two hypotheses:1. A long-term design project that integrates knowledge from multiple courses strengthens student knowledge retention. 2. A large-scale design project requiring tools from many courses improves student problem-solving and design skills.By integrating five semesters of the mechanical engineering curriculum into a cohesive whole, this project has the potential to transform the way undergraduate education is delivered. Before and after testing is being conducted to assess: a) Change in retention between courses and b) Change in student problem-solving and design skills.The centerpiece of the hybrid powertrain is the planetary gearset, which combines power from the air engine and electric motor to produce the desired output speed at the wheels. During the fall semester of their Junior year, the students design and fabricate a small planetary gearset, and conduct tests to assess its performance. The planetary gearset project is conducted in Machine Design, a core mechanical engineering course. This paper describes the planetary gearset assignment only -a description of the full hybrid powertrain project is given the papers listed in the References. Based on student feedback, an overwhelming majority of the students felt that the "hands on" project was valuable in the Machine Design course and enjoyed working on the project.Page 26.994.2

In a grating-coupled high-electron-mobility transistor, weak terahertz emission with wavelength around 400 m was observed by using a Fourier-transform spectrometer. The absolute terahertz emission power was extracted from a strong background blackbody emission by using a modulation technique. The power of terahertz emission is proportional to the drain-source current, while the power of blackbody emission has a distinct relation with the electrical power. The dependence on the drain-source bias and the gate voltage suggests that the terahertz emission is induced by accelerated electrons interacting with the grating.