External Switch Research Articles

External Oxidant-Dependent Reactivity Switch in Copper-Mediated Intramolecular Carboamination of Alkynes: Access to a Different Class of Fluorescent Ionic Nitrogen-Doped Polycyclic Aromatic Hydrocarbons.

An interesting case of external oxidant-controlled reactivity switch leading to a divergent set of ionic nitrogen-doped polycyclic aromatic hydrocarbons (N-doped PAHs), is presented here, which is quite unrecognized in copper-mediated reactions. In the current scenario, from the same pyridino-alkyne substrates, the use of the external oxidant PhI(OAc)2, in combination with Cu(OTf)2, gave N-doped spiro-PAHs via a dearomative 1,2-carboamination process; whereas, without the use of oxidant, an alkyne/azadiene [4 + 2]-cycloaddition cascade occurred to exclusively afford ionic N-doped PAHs. These newly synthesized N-doped PAHs further exhibit tunable emissions, as well as excellent quantum efficiencies.

IoT-BBMS: Internet of Things-Based Baby Monitoring System for Smart Cradle

The current number of working mothers has greatly increased. Subsequently, baby care has become a daily challenge for many families. Thus, most parents send their babies to their grandparents' house or to baby care houses. However, the parents cannot continuously monitor their babies' conditions either in normal or abnormal situations. Therefore, an Internet of Things-based Baby Monitoring System (IoT-BBMS) is proposed as an efficient and low-cost IoT-based system for monitoring in real time. We also proposed a new algorithm for our system that plays a key role in providing better baby care while parents are away. In the designed system, Node Micro-Controller Unit (NodeMCU) Controller Board is exploited to gather the data read by the sensors and uploaded via Wi-Fi to the AdaFruit MQTT server. The proposed system exploits sensors to monitor the baby's vital parameters, such as ambient temperature, moisture, and crying. A prototype of the proposed baby cradle has been designed using Nx Siemens software, and a red meranti wood is used as the material for the cradle. The system architecture consists of a baby cradle that will automatically swing using a motor when the baby cries. Parents can also monitor their babies' condition through an external web camera and switch on the lullaby toy located on the baby cradle remotely via the MQTT server to entertain the baby. The proposed system prototype is fabricated and tested to prove its effectiveness in terms of cost and simplicity and to ensure safe operation to enable the baby-parenting anywhere and anytime through the network. Finally, the baby monitoring system is proven to work effectively in monitoring the baby's situation and surrounding conditions according to the prototype.

Dual-Mode CMOS Power Amplifier Based on Load-Impedance Modulation

This letter presents a dual-mode CMOS power amplifier (PA) that has an improved efficiency using load-impedance modulation in the low-power mode (LPM) and a fully differential operation in the high-power mode (HPM). For the LPM, the transistor in the negative path of the differential pair is turned ON, as a switch, to appropriately modulate the load impedance for the transistor in the positive path using the output balun. An external switch is deployed to turn $V_{\text {DD}}$ OFF for the negative path. In order to verify the proposed concept, a dual-mode CMOS PA IC was designed using a bulk CMOS process and an off-chip output balun, and it was evaluated using the 920-MHz narrow-band Internet of Things signal with a bandwidth of 200 kHz and a peak-to-average power ratio of 5.7 dB. For the HPM, the implemented PA exhibited a gain of 24.1 dB, a power-added efficiency (PAE) of 44.3%, and an adjacent channel leakage power ratio (ACLR) of −33.9 dBc at an average output power of 27.7 dBm. For the LPM, a gain of 19.3 dB, a PAE of 37.7%, and an ACLR of −34.9 dBc were obtained at an average output power of 21.7 dBm.

Manual control of optical tweezer switching for particle trapping and injection

This work presents an optical switching model that the tweezer probe uses for manually switching the controlled by an external switch, in which the upward and downward switching can be operated and simultaneously switched. By using the microring resonator incorporated with the two non-linear phase modulators, the optical tweezer can be generated and the switching probes controlled. The switching time with the table force of ~2 fs is obtained. The tweezer force and torque are calculated and interpreted for molecule trapping and injecting from and to the trapping and the target surfaces. The relative forces and torques are calculated and plotted. In applications, the specific forces and torques can be controlled to perform the appropriate trapping and injecting. The switching time depends on the external switching module, which may be electronically controlled.

360° Phase Detector Cell for Measurement Systems Based on Switched Dual Multipliers

This letter presents a 360° phase detector cell for performing phase-shift measurements on multiple output systems. An analog phase detector, capable of detecting a maximum range of ±90°, has been used to perform a double multiplication of two signals, both in-phase and phase-shifted. The proposed solution broadens the frequency range beyond other solutions that require to fulfill the quadrature condition. Subsequently, the possibility of reaching the theoretical limit of phase shift within a hybrid coupler ($\varphi$ <;90° ± 90°) is discussed by using four straight-line equations to characterize the phase detector response. The proposed solution allows to extend up to 360° the phase detection range and provide an increased immunity with respect to both impedance mismatching and phase deviations within the hybrid coupler. To demonstrate the feasibility of the proposed design, a phase detector cell prototype has been implemented using a commercial hybrid coupler with a phase shift of 92.5° ± 0.5° at 3.1-5.9 GHz, an external switch and a microcontroller with 2 kB of memory. Measurements show a range of detection of 360° (±180°) across the tested frequency band of 2.7-6 GHz.

An integrated high voltage digital-to-analog converter for a reconfigurable antenna array

This paper presents an integrated high voltage digital-to-analog converter, which is fabricated in a 0.35 $${\upmu }$$ μ m high voltage CMOS technology (AMS H35), and can be applied in high voltage applications up to 115 V. The high voltage output is controlled by 8-bit digital input code. In order to improve the accuracy and decrease the required area, it is implemented by a low voltage DAC and a high voltage amplifier for boosting the controllable output voltage. Since the current consumption from the high voltage power supply is only 80 $${\upmu }$$ μ A, it can be powered by a charge pump which generates 115 V from a battery with 3.7 V DC. Combining with a 8*8 external high voltage switch array, the proposed high voltage digital-to-analog converter can drive up to 64 individual channels of antenna array with a voltage from 0 to 115 V. It will greatly reduce the complexity and cost of mobile applications which use tunable microwave devices and require high voltages. The feasibility is proved by post-simulation result and experimental test result. The proposed concept of the high voltage ASIC is also proved by a demonstrator.

Ambipolar and non-ambipolar diffusion in an rf plasma source containing a magnetic filter

By placing a magnetic filter across a rectangular plasma source (closed at one end with a ceramic plate and an rf antenna, and terminated at the opposite end by a grounded grid), we experimentally investigate the effect of conducting and insulating source walls on the nature of the plasma diffusion phenomena. The use of a magnetic filter creates a unique plasma, characterized by a high upstream electron temperature (Teu∼5 eV) near the rf antenna and a low downstream electron temperature (Ted∼1 eV) near the grid, which more clearly demonstrates the role of the source wall materials. For conducting walls a net ion current to ground is measured on the grid, and the plasma potential is determined by a mean electron temperature within the source. For insulating walls the plasma potential is determined by the downstream electron temperature (i.e., Vp∼5.2Ted in argon), and the net current to the grid is exactly zero. Furthermore, by inserting a small additional upstream conductor (that can be made floating or grounded through an external circuit switch), we demonstrate that the plasma potential can be controlled and set to a low (Vp∼5.2Ted), or high (Vp∼5.2Teu) value.

AMR (Active Magnetic Regenerative) refrigeration for low temperature

This paper reviews AMR (Active Magnetic Regenerative) refrigeration technology for low temperature applications that is a novel cooling method to expand the temperature span of magnetic refrigerator. The key component of the AMR system is a porous magnetic regenerator which allows a heat transfer medium (typically helium gas) to flow through it and therefore obviate intermittently operating an external heat switch. The AMR system alternatingly heats and cools the heat transfer medium by convection when the magneto-caloric effect is created under varying magnetic field. AMR may extend the temperature span for wider range than ADR (Adiabatic Demagnetization Refrigerator) at higher temperatures above 10K because magneto-caloric effects are typically concentrated in a small temperature range in usual magnetic refrigerants. The regenerative concept theoretically enables each magnetic refrigerant to experience a pseudo-Carnot magnetic refrigeration cycle in a wide temperature span if it is properly designed, although adequate thermodynamic matching of strongly temperature-dependent MCE (magneto-caloric effect) of the regenerator material and the heat capacity of fluid flow is often tricky due to inherent characteristics of magnetic materials. This paper covers historical developments, fundamental concepts, key components, applications, and recent research trends of AMR refrigerators for liquid helium or liquid hydrogen temperatures.

Review on detection of critical transition in ecosystems

Ecosystem with alternative stable states would respond abruptly to minor changes in the external conditions and switch into an alternative stable state with different ecosystem structures and functions when the system ap- proaches the transition threshold. This phenomenon is called critical transition. It is often the case that such transi- tion can result in marked changes in ecosystem services, which are much likely to impact the sustainable devel- opment of human being. It is difficult to predict the critical transitions in ecosystems, but the large amount of re- search in this field show that by monitoring some generic properties (i.e. early-warning signals) relating to eco- system status, we are able to discern if the system approaches the transition threshold; this can be used to predict the critical transitions in ecosystems. This paper summarizes the major findings and achievements in the field of detecting critical transitions in ecosystems. It first discusses the mechanism and consequence of critical transi- tions, and then introduces the basic theory behind the early-warning signals. We sum up the methods used to ex- tract early-warning signals both from temporal and spatial dimensions. Finally, challenges confronting the con- temporary research are summarized. In future, the application of early-warning signals should make full use of both temporal and spatial data and combine different indicators to improve our ability to forecast unfavorable en- vironmental events. Also, special attention needs to be paid to the relationship between critical transitions and

UV Light as External Switch and Boost of Molar-Mass Control in Iodine-Mediated Polymerization

UV-initiated iodine-mediated polymerization of n-butyl methacrylate employing an iodo chain-transfer agent and a photoinitiator was studied with respect to its kinetics and mechanism. UV irradiation was found to be a significant boost for molar-mass control compared to thermally initiated systems, drastically lowering dispersities from above 1.5 down to 1.1. The reason for this, as proven by extensive kinetic simulations, is the incessant C–I-bond cleavage and formation of free iodine on the nanomolar scale, which leads to a reversible termination mechanism coexisting to degenerative chain-transfer. In experiments with intermittent irradiation, the system was perfectly dormant with no polymerization occurring during the dark time, illustrating the potential as photoswitchable controlled polymerization system. Photopolymerization at elevated temperatures is presented as a tool for increasing polymerization rate while fully retaining molar-mass control. The presented system is highly robust and proceeds without the use of smelly or toxic additives, offering a cheap and green way to produce externally triggered well-defined polymer and extending the scope of iodine-mediated polymerizations.

Design of a digital controller for an LED driver with a digital dimming

This letter presents a new digital controller (DCL) with a new dimming method for high power-factor LED driver circuits. The core of proposed digital controller is based on a zero-voltage (ZVD) detection and a digital sine generator (DSG). By using the DSG, an effective dimming can be carried out easily. The proposed DCL was simulated and fabricated using the 1μm-650V DMOS process. The results obtained indicate that the inductor current waveform is in phase with the input voltage to gain a high power factor, because the inductor current is synchronized to the zero voltage signal from ZVD as expected. Also, the LED current changes according to the reference voltage, which is controlled by an external switch that adjusts the brightness of the LED.

Study on IGMP for PLC in Intelligent Manufacturing System

This paper discusses a new solution for IGMP (Internet Group Management Protocol) for PLC (Programmable Logic Controller) in intelligent manufacturing system. It is based on the study of a new PLC design with an Ethernet switch device 88E6165 embedded in it. The switch passes IGMP traffic from the external switch ports to the CPU (Central Processing Unit) for snooping and forwarding via the CPU Ethernet interface. The architecture of multi hosts in the intelligent manufacturing system is given in the paper. The use case(s), actors and process are also analyzed to perform the switch operations with IGMP. This process uses a switch manager to perform a manager role to periodically query all devices in the subnet and subsequently. It causes devices to re-join the multicast group of listeners for any stream in which they may be interested.

Fuel Injection System

The invention relates to a fuel-injection system (1) comprising at least one fuel-injection valve (1a) and an adapter that can be heated (1b), which is attached to a fuel rail (1c) and to the fuel-injection valve (1a) of the fuel-injection system (1). The fuel rail (1c) is equipped with a thermal switch (2), which is connected to an external door contact switch (3) and to the heatable adapter (1b). The thermal switch (2) has a thermal sensor to ensure a reliable start from cold. In said system, if the fuel temperature falls below a predefined fuel temperature, a changeover of the thermal switch (2) causes the fuel (8) to be heated.

Dynamic simulation of a parallel robot: Coulomb friction and stick–slip in robot joints

SUMMARYDynamic simulation in robotic systems can be considered as a useful tool not only for the design of both mechanical and control systems, but also for planning the tasks of robotic systems. Usually, the dynamic model suffers from discontinuities in some parts of it, such as the use of Coulomb friction model and the contact problem. These discontinuities could lead to stiff differential equations in the simulation process. In this paper, we present an algorithm that solves the discontinuity problem of the Coulomb friction model without applying any normalization. It consists of the application of an external switch that divides the integration interval into subintervals, the calculation of the friction force in the stick phase, and further improvements that enhance its stability. This algorithm can be implemented directly in the available commercial integration routines with event-detecting capability. Results are shown by a simulation process of a simple 1-DoF oscillator and a 3-DoF parallel robot prototype considering Coulomb friction in its joints. Both simulations show that the stiffness problem has been solved. This algorithm is presented in the form of a flowchart that can be extended to solve other types of discontinuity.

Printed coplanar two‐antenna element for 2.4/5 GHz WLAN operation in a MIMO system

AbstractA printed coplanar two‐antenna element suited for WLAN operation in the 2.4‐ and 5‐GHz bands for dual‐module applications in a MIMO system is proposed. The two‐antenna element is comprised of one planar inverted‐F antenna (PIFA) and one monopole antenna, both printed and integrated in a coplanar configuration on a narrow dielectric substrate with the dimensions 50 mm × 11 mm. The two antennas are excited using two separate feeds with a common ground plane. By utilizing two proposed elements spaced 10‐mm apart in the lateral direction with an optimized arrangement, the four‐antenna MIMO system obtained can achieve optimal isolation between any two of the four antennas. In comparison with the conventional dual‐band antenna with a single feed, the proposed two‐antenna element allows the 2.4‐ and 5‐GHz signals to be simultaneously received or transmitted with no external switch circuit between the antenna and modules required. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1635–1638, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23540

Switching of a TEA CO2laser with its own UV emitting parallel spark channels

The efficient operation of a TEA CO(2) laser wherein the parallel spark channel preioniser of the laser itself functioned as a switch is reported. Simultaneous closure of the parallel gaps without an external switch has been achieved by ballasting them with mutually coupled inductances. The repetitive operation capability of such a laser is also discussed.

An External Switch for Commercial Laser Pointers

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Enhanced Spin Injection into ZnO Semiconductor Measured byMagnetoresistance

We prepare 2×(NiFe/CoZnO)/ZnO/(CoZnO/Co)×2 spin valve structuresused for spin injection by sputtering and photolithography. In thejunctions, the free magnetic layer 2×(NiFe/CoZnO) and the fixedmagnetic layer (CoZnO/Co)×2 are used to realize the spin valvefunctions in the external switch magnetic field. Since the wide gapsemiconductor ZnO layer is located between the two magneticsemiconductor layers CoZnO, the electrical spin injection from themagnetic semiconductor CoZnO into the non-magnetic semiconductor ZnO isrealized. Based on the measured magnetoresistance and the Schmidtmodel, the spin polarization ratio in the ZnO semiconductor is deducedto be 11.7% at 90 K and 7.0% at room temperature, respectively.

Curved Ferroelectric Liquid Crystal Matrix Displays Driven by Field-Sequential-Color and Active-Matrix Techniques

This paper describes a curved field-sequential-color matrix display using fast-response ferroelectric liquid crystal. Black matrix and transparent electrode patterns were formed on a thin plastic substrate by a transfer method from a glass substrate. While a composite film of liquid crystal and micro-polymers of walls and fibers was formed between the flexible substrates by printing, laminating and curing processes of a solution of monomers and liquid crystal, the mechanical stability was enhanced by use of multi-functional monomers to form large display panels. The image pixels of the matrix panel were driven by an active matrix scheme using an external switch transistor array at a frequency of 180 Hz for intermittent three-primary-color backlight illumination. The flexible A4-paper-sized color display with 24 × 16 pixels and 60 Hz field frequency was demonstrated by illuminating it with sequential three-primary-color lights from light-emitting diodes of the backlight. Our display system is useful in various information displays because of its freedom of setting and location.

Switch-less operation of a TEA CO2 laser

We report here the operation of a UV pre-ionised mini-TEA CO2 laser where the use of an external switch has been dispensed with. This was rendered possible by making the preioniser spark array play a dual role- that of a switch as well as of a source of UV photons that pre-conditioned the inter-electrode volume.