As the electronics industry is integrating more and more new molecules to utilize them in logic circuits and memories to achieve ultra-high efficiency and device density, many organic structures emerged as promising candidates either in conjunction with or as an alternative to conventional semiconducting materials such as but not limited to silicon. Owing to rotaxane's mechanically interlocked molecular structure consisting of a dumbbell-shaped molecule threaded through a macrocycle, they could be excellent nanomachines in molecular switches and memory applications. As a nanomachine, the macrocycle of rotaxane can move reversibly between two stations along its axis under external stimuli, resulting in two stable molecular configurations known as “ON” and “OFF” states of the controllable switch with distinct resistance. There are excellent reports on rotaxane's structure, properties, and function relationship and its application to molecular electronics (Ogino, et al., 1984; Wu, et al., 1991; Bissell, et al., 1994; Collier, et al., 1999; Pease, et al., 2001; Chen, et al., 2003; Green, et al., 2007; Jia, et al., 2016). This comprehensive review summarizes [2]rotaxane and its application to molecular electronics. This review sorts the major research work into a multi-level pyramid structure and presents the challenges of [2]rotaxane's application to molecular electronics at three levels in developing molecular circuits and systems. First, we investigate [2]rotaxane's electrical characteristics with different driving methods and discuss the design considerations and roles based on voltage-driven [2]rotaxane switches that promise the best performance and compatibility with existing solid-state circuits. Second, we examine the solutions for integrating [2]rotaxane molecules into circuits and the limitations learned from these devices keep [2]rotaxane active as a molecular switch. Finally, applying a sandwiched crossbar structure and architecture to [2]rotaxane circuits reduces the fabrication difficulty and extends the possibility of reprogrammable [2]rotaxane arrays, especially at a system level, which eventually promotes the further realization of [2]rotaxane circuits.

Due to rapid development in mobile communication technology in recent years, the demand for high quality and high capacity networks with thorough coverage has become a major necessity. Several models have been developed for predicting wireless signal coverage in urban areas, but these models suffer from inadequately calculating certain conditions, such as weather and building materials, especially window size. In this paper, we propose a new path loss prediction model based on the measurement of new indicators, such as window size, temperature, and humidity conditions, after which an extensive statistical analysis using a linear regression technique was implemented in order to validate the new indicators. As the new indicators were incorporated into the Okumura model to derive a new path loss model, the results showed that the proposed model provides an accurate prediction of the received signal strength in a given propagation environment. Our model enhanced the prediction of path loss by 10% when compared to the Okumura and by 15% when compared to the COST-Hata.

In the not-too-distant future, humans will return to the Moon and step foot for the first time on Mars. Eventually, humanity will colonize these celestial bodies, where living and working will be commonplace. Energy is fundamental to all life. The energy that people use to sustain themselves on Earth, and in particular on these other worlds, is the integrated, safe production of electrical power, day and night. This paper proposes a radically new solution to this problem: Solar Tracking by day and a Solar Rechargeable Calcium Oxide Chemical Thermoelectric Reactor by night. Called the “Robotic End Effector for Lunar and Martian Geological Exploration of Space” (REEGES) Day/Night Power Generator Station, this form of thermoelectric power generation is mathematically modeled, simulation is performed, and a concept model design is demonstrated in this paper. The results of the presented simulation show the maximum total system output capability is 9.89 V, 6.66 A, and 65.9 W, with an operating time of up to 12 h, through a scalable design. This research provides instructions to the Space Research Community on a complete and novel development methodology for creating fully customized, configurable, safe, and reliable solar/thermoelectric day/night power generators, specifically meant for use on the Moon and Mars, using the Proportional-Integral-Derivative++ (PID++) Humanoid Motion Control Algorithm for its operation on a computationally lightweight microcontroller.