Room-Temperature Ionic Liquids with High Conductivities and Wide Electrochemical Windows

Room-temperature ionic liquids (RTILs), N-alkyl-N-methylpyrrolidinium (RMPyr⁺) and N-alkyl-N-methylpiperidinium (RMPip⁺) fluorohydrogenates formulated by RMPyr( HF )₂.₃F and RMPip( HF )₂.₃F ( R = ethyl, propyl, and butyl), have been synthesized by the reactions of the corresponding chlorides and anhydrous hydrogen fluoride. These RTILs exhibit relatively low viscosities (11.5-34.4 cP), high conductivities (12.3-74.6 mS cm⁻¹), and wide electrochemical widows around 5 V using glassy carbon electrodes. The fluorohydrogenate salts of symmetric cations, N, N-dimethylpyrrolidinium (DMPyr⁺) and N, N-dimethylpiperidinium (DMPip⁺) obtained by evacuation at room temperature are solids, exhibiting the composition of DMPyrF-2HF and DMPipF-2HF

Mixed Lubrication Analysis of Vane Sliding Surface in Rotary Compressor Mechanisms

In the compression mechanisms of a rotary compressor for air conditioners, a vane and a rolling piston are provided to separate the suction chamber and the compression chamber. The rolling piston is driven by the crank, and revolves on the axis of the shaft eccentrically, and also rotates on its own axis. The vane undergoes reciprocating motion, and its top usually comes into contact with the rolling piston by the spring force and the discharge pressure. The lubricating condition between the vane top and the rolling piston is severe because the contact pressure is high owing to the line contact of the vane top. For the prevention of scuffing, abnormal wear and so on, it is important to clarify the lubricating characteristics between the vane top and the rolling piston. Because the normal force acting on piston at vane contact is greatly influenced by the friction of vane sliding surface between the vane and the vane-slot, a mixed lubrication analysis of the vane sliding surface between the vane and the vane-slot is required to obtain the normal force acting on piston at vane contact accurately. In order to investigate the lubricating characteristics between the vane top and the rolling piston, a numerical analysis of the motion of the rolling piston and the motion of the vane considering the mixed lubrication of the vane sliding surface has been performed. The cases of different friction coefficient of the vane sliding surface at solid contact were calculated, and the results were compared. As a result, the effects of the friction of the vane sliding surface on the lubricating characteristics between the vane top and the rolling piston have been made clear

The Effect of the Anion Fraction on the Physicochemical Properties of EMIm(HF)nF (n= 1.0−2.6)

A series of molten salts EMIm(HF)nF's with different n values has been synthesized by the reaction of EMImHF2 and anhydrous hydrogen fluoride. The salts contain EMIm cation and some oligomeric fluorohydrogenate anions, (HF)nF-, of which the fraction changes with the change of n. A phase diagram of EMIm(HF)nF's (n = 1.0−2.6) has been constructed which suggests the presence of the stoichiometric compounds, EMIm(HF)1.5F and EMIm(HF)2F, in this range. Compared to the EMIm(HF)2.3F previously reported, EMIm(HF)nF's (n = 1.8−2.0) possess wider liquid temperature ranges because of their similar melting points and superior thermal stabilities at elevated temperatures. The electrochemical windows of EMIm(HF)nF's (n = 1.0−2.6) falls in the range of 2.9−3.4 V. The conductivity of EMIm(HF)nF's (n = 1.0−2.6) increases with the increase of n

A New Find of a Prboscidean Fossil from Nagano Prefecture, Central Japan

Article信州大学理学部紀要 6(1): 37-44(1971)departmental bulletin pape

A combined navigation strategy by a steering wheel and a mouse for a tank rescue robot

This paper applies our developed novice users oriented force feedback steering wheel interface and mouse interface to navigating a tank type rescue robot. By analyzing merits and limitation of operating each interface, we propose a combined navigation strategy by the two interfaces. The steering wheel interface consists of a force feedback steering control and a six monitors’ wall. Through this interface, users can navigate the tank robot like driving cars, while watching incoming videos. It provides a daily life operation method for novice users to navigate the tank rescue robot. The steering wheel interface is efficient in exploring open areas. For complex disaster fields, this interface requires users have skillful operation experiences, which take them more attention. The mouse-screen interface consists of a mouse and a camera’s view displayed in a computer screen. Through this interface, users can navigate the tank robot just by mouse clicking. Path planning and low-level controlling are realized by system automatically. The mouse-screen interface can realize exact navigation, especially needed in complex structures, without taking much attention. It gives users more time to care incoming information. The two interfaces can shift into each other at any time. The combined navigation strategy adopts merits of the two interfaces and compensates limitation of each of them. It provides an efficient operation method for novice users to navigate rescue robots.</p

A mechanical intelligence in assisting the navigation by a force feedback steering wheel for a snake rescue robot

We developed a snake rescue robot basing on the proposed mechanical intelligence. The mechanical intelligence is designed to avoid obstacles and to realize desired motions when the robot is navigated by a remote force feedback steering wheel interface. We use free joints to connect modules of the snake robot. Modules can freely turn according to their neighbors. An obstacle-avoiding wheel is mounted on the head of the snake robot. When the head encounters an obstacle, the wheel touches it first to transfer the sliding friction between the wheel and the obstacle into rolling friction, so that the head avoid the obstacle easily. A metal wire is used to link gears mounted on both sides of each module. When any part of the snake robot's body encounters an obstacle, the wire length of each side varies automatically to change the robot's body shape, so that the snake robot avoids the obstacle. The wire length of each side can also be adjusted by a motor. By adjusting the wire length of each side, the snake robot can move in the desired direction. The mechanical intelligence based snake rescue robot has light body, low cost and low computation cost. Experiment results show that the designed mechanical intelligence is effective in realizing desired robot motions together with the force feedback steering wheel interface.</p

A combined navigation strategy by a steering

This paper applies our developed novice users oriented force feedback steering wheel interface and mouse interface to navigating a tank type rescue robot. By analyzing merits and limitation of operating each interface, we propose a combined navigation strategy by the two interfaces. The steering wheel interface consists of a force feedback steering control and a six monitors’ wall. Through this interface, users can navigate the tank robot like driving cars, while watching incoming videos. It provides a daily life operation method for novice users to navigate the tank rescue robot. The steering wheel interface is efficient in exploring open areas. For complex disaster fields, this interface requires users have skillful operation experiences, which take them more attention. The mouse-screen interface consists of a mouse and a camera’s view displayed in a computer screen. Through this interface, users can navigate the tank robot just by mouse clicking. Path planning and low-level controlling are realized by system automatically. The mouse-screen interface can realize exact navigation, especially needed in complex structures, without taking much attention. It gives users more time to care incoming information. The two interfaces can shift into each other at any time. The combined navigation strategy adopts merits of the two interfaces and compensates limitation of each of them. It provides an efficient operation method for novice users to navigate rescue robots. </p

Security Analysis of SFrame

As people become more and more privacy conscious, the need for end-to-end encryption (E2EE) has become widely recognized. We study herein the security of SFrame, an E2EE mechanism recently proposed to the Internet Engineering Task Force for video/audio group communications over the Internet. Despite being a quite recent project, SFrame is going to be adopted by a number of real-world applications. We inspect the original specification of SFrame and find critical issues that will lead to impersonation (forgery) attacks with a practical complexity by a malicious group member. We also investigate the several publicly available SFrame implementations and confirm that this issue is present in these implementations

Polarization envelope helicity dependent photovoltage in GaAs/Al03Ga07As modulation-doped quantum well

In this study, we demonstrate the switching of the direction of the photocurrent in an n-type GaAs/Al0.3Ga0.7As modulation-doped quantum well using a polarization pulse-shaping apparatus containing a 4f setup. The right- and left-polarization-twisting pulses with a polarization rotation frequency in the THz-regime are incident on a modulation-doped quantum well. The results show that the sign of the photovoltage is dependent on the direction of rotation of the polarization-twisting pulses, which can be explained by the circular photogalvanic effect combined with the production of a classical edge photocurrent from the acceleration of free electrons in the vicinity of the sample edge by the incident optical electric field. The wide range over which the polarization-rotation frequency may be tuned makes this method a powerful tool to investigate the response of an extensive variety of materials in the THz-regime