Circuit Transmission Research Articles

Review of Technological Advances in High Temperature Overhead Line Composite Conductors

ACSR (Aluminium Conductor Steel Reinforced) conductors consisting of pure aluminum wires helically stranded around a core of high strength galvanized steel core wires are widely used in overhead transmission line applications. While the steel wires provides the required strength, the outer aluminium serves as electricity conducting member. The thermal rating or ampacity of conductors is the maximum current that a circuit can carry within the temperature limits as dictated by the allowable conductor sag or by the annealing onset temperature of the conductor, whichever is lower. On a continuous basis, ACSR may be operated at temperatures up to 100°C without any significant change in the conductor’s physical properties. Above 100°C, aluminum wires loses tensile strength over time and becomes "fully annealed" giving rise to increased thermal expansion of the conductor; this causes excessive sagging reducing the clearance between the ground and the energized conductors.
 While, the electric utilities are posed with increased challenges of production of additional capacities and building new transmission circuits to meet the ever growing demand and the high cost and environmental restrictions of constructing new lines, methods are being explored to increase their capacity with minimum changes in the existing towers. Replacement of the existing conductor with a advanced high temperature composite (HTC) conductors operating upto temperatures of 200°C with reduced sagging characteristics have been attempted and an increase in capacity of 30-80%, can be achieved through application of these composite conductors.
 The advanced HTC conductors with varied combinations of core material and outer conducting wires are being tried so as to achieve wide ranging properties. In general, HTC conductors features the combinations of either soft aluminum wires with ultra high strength steel or temperature resistant aluminium with or fiber reinforced metal/polymer matrix composites as the core. Both the alumina fiber reinforced temperature resistant aluminium metal matrix composite and the carbon fiber reinforced high temperature polymer resin composite wires as the core material appears to have favorable applications. The comparative performance of the HTC depends on the degree to which both outer aluminum strand and reinforcing core’s physical properties are stable at high temperature and on the elastic, plastic, and thermal elongation of the combined HTC.
 The summary of various developments realized in the area of composite conductors and their relative merits and demerits have been discussed in detail.

Frequency-hopping mechanism and control method for nonlinear parity-time-symmetric wireless power transfer systems

Nonlinear parity-time-symmetric wireless power transfer (NPTS-WPT) is a novel wireless power transfer technology. NPTS-WPT systems exhibit the resonant frequency bifurcation phenomenon in the strong coupling region. However, working frequency selection mechanisms and control methods for use in the bifurcation region remain unclear. In this study, the description function method was used to model and analyze the dynamics of NPTS-WPT systems. The frequency stability, evolution and convergence characteristics of resonant frequency bifurcation were studied for varying distances between the receiver (Rx) and transmitter circuits varies. In addition, the loop detuning characteristics and the mechanism by which the amplification factor of the operational amplifier influences the system’s frequency-hopping behavior were determined. The detuning rate must be greater than the detuning tolerance to cause resonant frequency-hopping. Moreover, we propose a method to induce changes in the natural frequency of the Rx circuit by adding a detuning control circuit at the Rx, thereby allowing the resonant frequency to be selected and controlled. Finally, the conclusions from the theoretical analysis and the feasibility of the proposed frequency control methods were validated using an experimental system. The proposed resonant frequency control methods offer a viable method for directional frequency selection and artificial frequency control in NPTS-WPT systems operating in the strong coupling region.

Fiber-specific white matter alterations in Parkinson’s disease patients with freezing of gait

Freezing of gait (FOG) is a gait disorder that usually occurs in advanced stages of Parkinson's disease (PD). Understanding the underlying mechanism of FOG is important for treatment and prevention. Previous studies have investigated white matter (WM) structure to explore the pathology of FOG. However, the pathology is still unclear, possibly due to the methodological limitation in identifying specific fiber tracts. This study aimed to investigate tract-specific WM structural changes in FOG patients and their relationships with clinical characteristics. We enrolled 19 PD patients with FOG (PD-FOG), 19 without FOG (PD-woFOG) and 21 controls. Fixel-based analysis is a novel framework to avoid the effect of crossing fibers, which provides the metrics to assess WM morphology. By combining a method for segmenting fibers, we identified abnormalities in the specific fiber tracts. Compared to PD-woFOG, PD-FOG showed significant increased fiber-bundle cross-section (FC) in the corpus callosum (CC), fornix (FX), inferior longitudinal fasciculus (ILF), striato-premotor (ST_PREM), superior thalamic radiation (STR), thalamo-premotor (T_PREM), increased fiber density and cross-section (FDC) in the STR, and decreased fiber density (FD) in the CC and ILF. Additionally, the ILF was correlated with motor, cognition and memory, the CC was correlated with anxiety, and the T_PREM was also correlated with cognition. In conclusion, in addition to impairments of WM found in PD-FOG, we found enhancements in WM, which may imply compensatory mechanisms. Furthermore, multiple fiber tracts were correlated with clinical characteristics, especially the ILF, validating the involvement of transmission circuits of multiple distinct information in mechanisms of FOG.

IPD dual-band filter chip with a large frequency ratio for 5G microwave and millimeter-wave applications

In this paper, a dual-band integrated passive device (IPD) filter with an almost arbitrary large frequency ratio is proposed and it has passbands at sub-6GHz and millimeter-wave frequencies. The method to design this kind of filter is summarized. A comprehensive qualitative analysis shows how the coupled lines are used to separate high-frequency (HF) and low-frequency (LF) signals and multiple open stubs as well as LC resonators are involved in this kind of filter. According to the odd- and even-mode analytical methods, the relationship between critical transmission zeros (TZs) and circuit parameters of the dual-band filter is explained. A good selectivity is achieved to suppress intermodulation signals. A prototype of the dual-band filter chip working at 4.80 GHz and 28.29 GHz with 3-dB fractional bandwidths of 53.81% and 24.52% is implemented, indicating that it supports more 5G bands than previous designs and has a good application prospect.

The bonding and intercalation efficacy of polyethyleneimine enhanced BiOBr semiconductor-organic framework degradation and detoxification of bisphenol AF

Photocatalysis is a promising method for water pollution treatment, but it is challenged due to its low efficiency and insufficient understanding of the toxicity after degradation. In this work, we construct a polyethyleneimine-enhanced BiOBr semiconductor organic framework (PEI/BiOBr SOF) by utilizing PEI's bonding and intercalation effects. PEI/BiOBr SOF enhances the photocatalytic degradation of bisphenol AF (BPAF) at a reaction rate 10 times that of BiOBr. Under the dual effects of intercalation and bonding, PEI/BiOBr SOF can realize extended the light absorption, increase the specific surface area and surface-active sites, inhibit carrier complexation, and promote the production of reactive oxygen species. The toxicity changes of the BPAF were evaluated by combining chemical product analysis and biological toxicity experiments. The mutual validation of the toxicity prediction results of the ECOASR product and the zebrafish toxicity experiment confirmed that the toxicity of BPAF decreased after degradation. Furthermore, the mechanism of photocatalytic degradation and detoxification of BPAF with PEI as the circuit of charge transmission of the BiOBr SOF was proposed.

Crosstalk Analysis of Delay-Insensitive Code in High-Speed Package Interconnects.

The development of integrated circuits has increased the size of chip interconnects, which has brought challenges to interconnect design in chip packages. The closer the spacing between interconnects, the higher the space utilization, which can cause severe crosstalk problems in high-speed circuits. In this paper, we applied delay-insensitive coding to the design of high-speed package interconnects. We also analyzed the effect of delay-insensitive coding on crosstalk improvement in package interconnects at 26 GHz for its high crosstalk immunity. Compared to the synchronous transmission circuit, the 1-of-2 and 1-of-4 encoded circuits designed in this paper can reduce crosstalk peaks by 22.9% and 17.5% on average at a wiring spacing of 1-7 μm, which can achieve closer wiring spacing.

Realisation of the reconfigurable pulsed high magnetic field facility and its scientific application at Wuhan National Pulsed High Magnetic Field Centre

AbstractTo generate arbitrary shape magnetic field waveforms for advanced scientific research, a reconfigurable pulsed high magnetic field facility (PHMFF) was developed at Wuhan National Pulsed High Magnetic Field Centre (WHMFC). First, the basic elements of PHMFF are introduced, and a ternary physical model composed of energy storage unit, magnet, transmission circuits and other auxiliary units is summarised to describe various magnetic field systems. Second, in order to realise the reconfiguration of magnetic field systems based on detailed elements, the control system with the ability of dynamic construction and control sequence reconfiguration is designed. On this basis, the PHMFF has been realised and various magnetic field systems are constructed to produce arbitrary shape magnetic field waveforms, such as half‐sine, ultra‐high, flat‐top and repetitive field pulses, which not only enhances the capability and efficiency of PHMFF, but also makes more scientific research possible in pulsed magnetic fields. So far, a peak magnetic field of 94.8 T, a flat‐top magnetic field of 64 T/10 ms and a repetitive magnetic field waveform of 20 T/60 Hz have been achieved, and some experiments and studies on the physical properties of materials have been carried out at WHMFC.

Application of a secure data transmission with an effective timing algorithm based on LoRa modulation and chaos

In today's technology, remote control or access is widely used in many platforms. However, the fact that remotely controlled platforms are open to external attacks or not secure enough which can have serious negative consequences. In this paper, a real-time LoRa modulation based data transmission application is achieved. The security of remotely transmitted data is not only provided with a basic encryption structure, but also a confirmation signal based transceiver system is designed in which the required process is performed only with a certain time interval. Firstly, the data to be transmitted is mixed with a secret key using XOR operation then transmitter creates a random period of time that specifies how long after the confirmation signal will be sent relative to the data signal. Hence, the entire system security is enhanced by the timing algorithm running with millisecond precision between the transceiver circuits. Encryption of the confirmation signal in a similar structure as the data signal improves security of the entire system. In this application, a PWM signal containing voltage information has been successfully transmitted in ciphered form using LoRa modulation. The designed algorithm for the receiver and transmitter circuits has been tested and verified in real time application. Experimental results show that the proposed scheme can be applied to any application-based communication system.

Integration of Wireless Power Transfer Technology With Hierarchical Multiwalled Carbon Nanotubes-Polydimethylsiloxane Piezo-Responsive Pressure Sensor for Remote Force Measurement

Integrating sensory devices with wireless power transfer technology for remote sensing (RS) requires the implementation of complex electronic circuitry and communication protocols. To overcome this challenge and remotely monitor mechanical force, we directly integrated piezo-responsive porous multiwalled carbon nanotubes (MWCNTs)/polydimethylsiloxane (PDMS) nanocomposites with a near-field wireless power transfer system. The wireless system transfers power bidirectionally between the transmitter and the sensing receiver at the resonant frequency of 13.56 MHz. The detection principle is based on the mechanical force-induced impedance changes in the receiver circuit. The modulated impedance signal is detected wirelessly at the transmitter circuit via a full-bridge rectifier and a smoothing capacitor. Furthermore, we demonstrate the wireless monitoring of finger bending and applied force using our flexible and disposable sensor without using any energy storage devices. The results suggest a response and recovery time of 400 ± 50 ms, strain sensitivity of 24.73, and pressure sensitivity of 0.98. Our approach adds a new path for disposable haptic-based sensory applications that do not require complex communication protocols in medical, robotics, and other fields.

Whistler‐Mode Transmission Experiments in the Radiation Belts: DSX TNT Circuit Simulation and Data Analysis

AbstractHigh‐power transmission experiments in the very low frequency (VLF) mode have been conducted by the US Air Force Research Laboratory’s Demonstration and Science Experiments (DSX) satellite in the radiation belts using a novel transmitter that automatically tunes to find the resonance frequency of the transmitter circuit including the antenna. The resulting voltage–frequency curves are used to derive antenna impedance at the resonance. The analysis shows that the antenna reactance is far less than that of a dipole antenna in free space. The derived radiation resistance is up to several tens of kilo Ohms. Most interestingly, it is found that the radiation resistance is inversely proportional to the square of transmission wave frequency. The transmitted power can be up to 80 W for the DSX transmitter with an 82‐m long tip‐to‐tip antenna, showing that the high‐power VLF transmission is feasible. Whistler wave transmission inside the higher‐density plasmasphere is more efficient. Data analysis indicates that the antenna impedance does not vary systematically with the antenna orientation angle relative to the ambient magnetic field. The previous dominant theoretical studies yield not only incorrect values of the impedance but a completely different frequency dependence than that derived from DSX experiments. Instead, the recent theories correctly capture both the antenna impedance magnitude and the frequency dependence.

Research on Transmission Line Motion Condition Monitoring Device and Communication Networking

In order to ensure the reliability of transmission line operation, it is necessary to carry out effective monitoring of its motion state, and master the running state of transmission line in real time by means of data analysis and comparison. During this period, transmission line motion state monitoring device is bound to be used. However, in order to ensure the effectiveness of transmission line monitoring, it is necessary to add communication network into the motion state monitoring device, so as to improve the reliability of transmission line data acquisition, transmission and analysis, and ensure the normal and safe operation of transmission circuit.

The Development of Solid-state Pulse Generator based on Marx Circuit with Chopping Switch

A solid-state pulse source is mainly formed by replacing the spark switch in a traditional pulse source with semiconductor switch device. Compared with conventional gas switch devices such as spark switches, semiconductor switch devices have the advantages of high work repetition frequency, long service life, small size, high efficiency, high reliability, easy control, and active shutdown. However, there are still problems, such as the solid-state switch being easily broken down by high voltage, the rising and falling edges of the pulse being slow, and the loss is enormous. In this paper, a solid-state pulse generator based on Marx with a chopping switch circuit is developed, which effectively solves the above problems. The pulse generator comprises DC power, a switching power circuit, a Marx circuit with a chopping switch, a serial port touch screen, and an optical fiber transmission circuit.

Perspectives of vector management in the control and elimination of vector-borne zoonoses.

The complex transmission profiles of vector-borne zoonoses (VZB) and vector-borne infections with animal reservoirs (VBIAR) complicate efforts to break the transmission circuit of these infections. To control and eliminate VZB and VBIAR, insecticide application may not be conducted easily in all circumstances, particularly for infections with sylvatic transmission cycle. As a result, alternative approaches have been considered in the vector management against these infections. In this review, we highlighted differences among the environmental, chemical, and biological control approaches in vector management, from the perspectives of VZB and VBIAR. Concerns and knowledge gaps pertaining to the available control approaches were discussed to better understand the prospects of integrating these vector control approaches to synergistically break the transmission of VZB and VBIAR in humans, in line with the integrated vector management (IVM) developed by the World Health Organization (WHO) since 2004.

Partially underground transmission circuits: safety issue for current and future power systems

An underground cable is often used as the interface between an overhead line and a substation where it is impractical to obtain an overhead right of way or to avoid environmentally sensitive areas. The transition from an overhead line to the underground cable usually takes place at cable sealing end compounds or transition stations. At the moment there is not adequate information in the national as well international standards on safety at these installations. This paper describes the earthing assessment of a 132 kV cable sealing end compound. A fault transfer phenomenon at the cable sealing end compound is discussed and simulated using the computer method. It is demonstrated that cable sealing end compounds can exhibit higher earth potential rise (EPR) for either end substation fault instead transitions points fault when such faults are fed by a combination of overhead line and underground cable. The analysis steps presented in this paper can be used as a guide for future works within this area.

Investigation of temperature variations on a Class-E inverter and proposing a compensation circuit to prevent harmful effects on biomedical implants

In this paper, a Class-E inverter and a thermal compensation circuit for wireless power transmission in biomedical implants are designed, simulated, and fabricated. In the analysis of the Class-E inverter, the voltage-dependent non-linearities of Cds, Cgd, and RON as well as temperature-dependent non-linearity of RON of the transistor are considered simultaneously. Close agreement of theoretical, simulated and experimental results confirmed the validity of the proposed approach in taking into account these nonlinear effects. The paper investigated the effect of temperature variations on the characteristics of the inverter. Since both the output power and efficiency decrease with increasing temperature, a compensation circuit is proposed to keep them constant within a wide temperature range to enable its application as a reliable power source for medical implants in harsh environments. Simulations were performed and the results confirmed that the compensator enables significant improvements by maintaining the power and efficiency almost constant (8.46 ± 0.14 W and 90.4 ± 0.2%) within the temperature range of − 60 to 100 °C. Measurements performed at 25 °C and 80 °C with and without the compensation circuit were in good agreement with the theoretical and simulation results. The obtained measured output power and efficiency at 25 °C are equal to 7.42 W and 89.9%.

Multiparallel and Flexible Expansion of Single-Switch WPT Inverter by Magnetic Integration

Aiming at the problem that the single-switch inverter for wireless power transmission circuit cannot realize the parallel connection of three or more inverters, a scheme that can arbitrarily expand the number of parallel inverters by changing the circuit structure is proposed. In this article, the current sharing coil (InterCell Transformer) is used to share the current between the branches to improve the system's stability. By adding a current-increasing <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> resonant network, the output voltage can be adjusted more flexibly, and the system volume can be reduced by applying the principle of magnetic integration. Then, the complex frequency-domain model is innovatively used to accurately express the single-switch inverter circuit, which is conducive to the equivalent analysis of its various derived circuits. Finally, a parallel experimental prototype is built. When the output voltage is 164 V and the current is 11 A, the maximum efficiency is 92.1%. The experimental results show that the scheme is reasonable, feasible, and reliable.

Inhibition of the retinal orexin receptors affects the hypothalamic-pituitary-gonadal axis through retinal pituitary adenylate cyclase activating polypeptide (PACAP) in male Wistar rats

Orexins A and B (OXA and OXB) and their receptors are expressed in the retina of both human and rodents and play a vital role in regulating signal transmission circuits in the retina. There is an anatomical-physiological relationship between the retinal ganglion cells and suprachiasmatic nucleus (SCN) through glutamate as a neurotransmitter and retinal pituitary adenylate cyclase-activating polypeptide (PACAP) as a co-transmitter. SCN is the main brain center for regulating the circadian rhythm, which governs the reproductive axis. The impact of retinal orexin receptors on the hypothalamic-pituitary-gonadal axis has not been investigated. Retinal OX1R or/and OX2R in adult male rats by 3 µl of SB-334867 (1 µg) or/and 3 µl of JNJ-10397049 (2 µg) were antagonized via intravitreal injection (IVI). Four time-periods were considered (3, 6, 12, and 24 h) for the controls without any treatment, SB-334867, JNJ-10397049, and SB-334867 + JNJ-10397049 groups. Antagonizing retinal OX1R or/and OX2R resulted in a significant elevation of retinal PACAP expression compared to control animals. In addition, expression of GnRH increased non-significantly in the hypothalamus over the 6 h of the study, and the serum concentration of LH decreased significantly in the SB-334867 group after 3 h of injection. Furthermore, testosterone serum levels declined significantly, especially within 3 h of injection; serum levels of progesterone were also exposed to a significant rise at least within 3 h of injection. However, the retinal PACAP expression changes were mediated by OX1R more effectively than by OX2R. In this study, we report the retinal orexins and their receptors as light-independent factors by which the retina affects the hypothalamic-pituitary-gonadal axis.

Emerging role of microglia and astrocyte in the affective-motivational response induced by a rat model of persistent orofacial pain

Few studies are approaching the neural basis underlying the aggregation of emotional disorders in orofacial pain despite the stress, depression, and anxiety are some of the most commonly reported risk factors. Using a persistent orofacial pain rat model induced by complete Freund's adjuvant (CFA) injection into the temporomandibular joint, we have investigated the plasticity astrocytes and microglia key brain regions for the affective-emotional component of pain. We measured the expression and morphologic pattern of reactivation of glial fibrillary acidic protein (GFAP, astrocyte marker) and Iba-1 (microglial marker) by western blotting and immunohistochemistry analysis. The results showed no alterations on motor activity during inflammatory pain, indicating an exclusive effect of nociceptive behavior on the plasticity of limbic regions. CFA-induced temporomandibular inflammation changed GFAP and Iba-1 expression in distinct regions related to emotional behavior in a time-dependent manner. A significant increase in GFAP and Iba-1 expression was observed in the central nucleus of the amygdala, hippocampus and periaqueductal grey matter from day 3 to day 10 post-CFA injection. Moreover, a positive correlation between GFAP and Iba-1 upregulation and an increased mechanical hypersensitivity was observed. Conversely, no change on GFAP and Iba-1 expression was observed in the hypothalamus and colliculus during orofacial inflammatory pain. Our data suggest an important role for glial cells in the affective-motivational dimension of orofacial pain beyond their well-explored role in the traditional nociceptive transmission circuits.

A novel QCA circuit-switched network with power dissipation analysis for nano communication applications

Today, communication links and networks are essential in transmitting data and information. Moreover, information sharing in communication devices and networks has become necessary, routine, and unavoidable. Consequently, designing and manufacturing high-speed nano-scale devices with ultra-low power consumption is very important. Among the emerging paradigms in nanotechnologies, quantum-dot cellular automata (QCA) is very popular in communication sciences. In the present study, we optimize the design and implementation of a QCA crossbar switch and use it in transmitter and receiver circuits. Subsequently, a circuit-switched network in QCA technology is implemented using these devices. All the designed circuits are coplanar with the minimum number of cells, optimal area and latency, and low power consumptions, which employ standard QCA design rules and show superiority and advantages compared to the previous designs.

Li-Fi Based V2V Communication Technology

This paper presents the latest technology called as LI-FI which has been developing a lot in few years. Using the concept of LI-FI two vehicle are communicated with the help of LEDs bulbs with the help of transmitter and receiver circuit. With the help of this technology the road accident can be controlled and much human life can be saved. A very chip device called as ultrasonic sensor which is used to measure the distance is used here just to communicate the two vehicles when they come in the contact in some range which is preferred for the ultrasonic sensor. Using this LI-FI the data are transmitted from one vehicle to another the data that is transmitted through LIFI can be any data like audio, video or text. This concept can be implemented at very low cost and with higher efficiency. The data that is transmitted through LIFI can be any data like audio, video or text. This technology was introduced few years back, which needs more systematic enquiry on its sustain ability for traffic control purpose. This concept can be implemented at very low cost and with higher efficiency.