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With the rapid development of embroidered electronics, the research on microstrip lines as important connecting devices is crucial. Although the proposed research has explored the influence of embroidery parameters on some electrical properties of embroidered electronics, it is difficult to design and fabricate embroidered microstrip lines (EMLs) with specific transmission performance based on existing research. Therefore, in order to better design and fabricate EMLs with good transmission performance, the effect of embroidery parameters on their transmission performance needs further exploration. In this work, relevant models to simulate their transmission performance was proposed. Firstly, considering the cases where the conductive yarn is only distributed on the fabric surface as well as in both the surface and the thickness direction of the fabric, two geometry models are constructed to simulate the path of the conductive yarn in the embroidered conductor strip. Based on this, the transmission performances of the EML are simulated and analyzed. Then, two different sets of embroidered conductor strips were manufactured to fabricate microstrip line, and their transmission performance was tested to verify the rationality and accuracy of the above simulation model. Finally, based on simulation analysis and experimental testing, the influence of stitch spacing and stitch length on the transmission performance of EMLs are investigated, and the prediction bias of the models is analyzed. It is believed that the proposed model will provide a theoretical basis for the design of EMLs. [ABSTRACT FROM AUTHOR]

The non-circular planetary gear train is a critical component of the hydraulic motor. It consists of internal and external non-circular gears with variable centre distance and several planetary gears. Transmission performance of the planetary gear train is considerable important to the overall structure analysis. In this research, two kinds of design methods are used for 6-8 type non-circular gear hydraulic motor. The high-order ellipse and double circular arc non-circular planetary gear train pitch curves are designed respectively. The influence of different modelling methods on the transmission performance of the whole planetary gear train are discussed. The results show that in the transmission process of the non-circular gear motor planetary gear train, the abrupt change of the planetary gear speed and the abrupt change of the rotational angular velocity of the planetary gear are located at the largest and smallest direction of the inner ring gear. The volume of each closed chamber of the motor changes at different times, resulting in the overall displacement pulsation. Under the same conditions, double arc type non-circular gear hydraulic motor than higher-order ellipse non-circular gear hydraulic motor in the same chamber work cycle can be in and out of more volume of oil, with better transmission smoothness. [ABSTRACT FROM AUTHOR]

The development of high-speed motors has stimulated the demand for high-speed reducers. In response to the lack of research on high-speed reducers and the challenge of developing high-speed transmission systems, this study proposes a novel wedge-loading planetary traction drive (WPTD). First, a more accurate theoretical analysis model is established by considering the combined effects of elastic deformation, loading state, and a elastohydrodynamic lubrication (EHL) traction mechanism. Second, the mixed thermal EHL model is introduced into the performance analysis of traction drive for the first time. The fitting formulas for predicting traction contact behavior are derived, and a performance analysis method for all line-contact traction drives is presented. Third, the loading performance, transmission characteristics, and the influence of different parameters on the transmission characteristics of WPTD are analyzed. Finally, the theoretical model is validated by prototype performance tests. The results show that the loading mechanism demonstrates a good self-adaptive loading effect, and WPTD achieves a peak efficiency of 96%. Additionally, WPTD delivers superior efficiency and vibration and noise performance because of its smooth power-transfer characteristics, thereby providing a possible solution for high-speed and low-vibration transmissions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The short flexspline harmonic drive has the advantages of a small axial size and a compact structure. However, unlike the ordinary cup-shaped flexspline with a long cylinder, a steel flexspline with a short cylinder often leads to concentrated stress and transmission failure due to inaccurate spatial meshing. This paper proposes a harmonic drive made of carbon fiber-reinforced polyetheretherketone (CF/PEEK) composite to solve this problem. The finite element method is employed to calculate and analyze the key technical performance of the composite material and the traditional steel harmonic drive. Results indicate the good vibration characteristics, fatigue life, and excellent load capacity of the new composite harmonic drive despite sacrificing some transmission accuracy. This work provides a new research method for designing a short flexspline harmonic drive using composite materials and a theoretical basis for designing a CF/PEEK short flexspline harmonic drive. [ABSTRACT FROM AUTHOR]

The contact quality between geometric features significantly affects the assembly accuracy and dynamic performance of mechanical products. However, accurate and efficient contact problem solving is currently a common challenge in the fields of tolerance analysis and tooth contact analysis (TCA). In this paper, a tolerance analysis method for gear mechanisms considering form deviations and elastic-plastic contact behaviors is proposed. Specifically, tolerance modeling of systematic and random deviations on tooth surfaces is represented by skin model shapes (SMS). Elastic-plastic contact behaviors including contact deformation, status, and stress distribution are modeled and calculated by a modified boundary element method (BEM). The accuracy and efficiency of this BEM algorithm are verified by comparing with the finite element method (FEM), indicating that the BEM can greatly improve the computational efficiency while maintaining high solution accuracy. A case study for a pair of spur gears demonstrates the significant effects of contact behaviors on transmission performance. This research provides an effective method to introduce mechanical contact behaviors in tolerance analysis of gear mechanisms. In addition, the contact simulation results can also be adopted in the analysis of vibration, reliability, and other aspects. • An accurate and efficient tolerance analysis method for gear mechanisms is proposed. • Real tooth surface topography and elastic-plastic contact behaviors are considered. • Systematic and random tooth surface deviations are represented by skin model shapes. • Elastic-plastic contact behaviors are modeled by a modified boundary element method. [ABSTRACT FROM AUTHOR]

A new type of rotary reducer is urgently needed in engineering to improve the low efficiency of single point drive operation for flat single axis photovoltaic tracking brackets, in order to adapt to complex environments and reduce costs. For this purpose, a cylindrical worm helical gear toroidal worm multi-point drive rotary reducer is designed, and performance testing and analysis are conducted. Firstly, analyze and compare the installation position and transmission mechanism of the multi-point drive rotary reducer with that of the single point drive. Secondly, the performance of the rotary reducer under rated output torque and overturning torque is numerically simulated using Romax software, and a comprehensive performance testing platform for the rotary reducer is built to test the transmission performance of the prototype under rated output torque and overturning torque. The results show that multi-point drive can withstand larger loads compared to single point drive, and the overall stability of the tracking bracket is stronger; the larger the rated output torque value, the greater the stress value of the worm gear; the overall stress value and deformation of the secondary transmission mechanism under the overturning torque meet the actual working condition requirements; the experimental test does not cause significant damage inside the reducer, and the simulation and experimental results are in good agreement. The design of the rotary reducer meets the practical working characteristics of the flat single axis photovoltaic tracking bracket under harsh working conditions, and can provide theoretical reference and support for improving the photovoltaic conversion efficiency construction of photovoltaic power stations.

For the commercial wavelength division multiplexing passive optical network (WDM-PON) with standard single-mode fiber SSMF-28 and 1:64 passive fiber branching at its far end (RN) and 100 GHz C-band continuous wavelength (CW) lasers, the maximum coverage and optimal transmission power of STM-16 and STM-64 with external modulators at different speeds and wave numbers (4λ, 8λ and 16λ) are obtained, respectively. The performance parameter of the high data rate WDM-PON system is analyzed with respect to a number of channels and reach. In order to improve the network utilization and receiving efficiency, the influence of different channels and transmission distances on the performance of high data rate WDM-PON system is analyzed. Simulation analysis with Optisystem15.0. The maximum transmission power required to achieve the maximum transmission distance under the condition of nonlinear constraints is obtained. In order to save power consumption, the configuration of each multi-band PON is optimized in terms of transmission power. It is found that WDM-PON system has to compromise between aggregated data rate and system reach. Future software defined access network reconfigure the access network depending on the dynamic demand and the resources available. Hence depending on the distance between the optical line terminal (OLT) and optical network unit (ONU) guaranteed data rate can be estimated. ONU is equipped with a tunable optical filter (TOF) hence future wavelength can be reconfigured by both service provider and user. It makes it possible for software to customize optical access network. [ABSTRACT FROM AUTHOR]

The development of high-speed motors has stimulated the demand for high-speed reducers. In response to the lack of research on high-speed reducers and the challenge of developing high-speed transmission systems, this study proposes a novel wedge-loading planetary traction drive (WPTD). First, a more accurate theoretical analysis model is established by considering the combined effects of elastic deformation, loading state, and a elastohydrodynamic lubrication (EHL) traction mechanism. Second, the mixed thermal EHL model is introduced into the performance analysis of traction drive for the first time. The fitting formulas for predicting traction contact behavior are derived, and a performance analysis method for all line-contact traction drives is presented. Third, the loading performance, transmission characteristics, and the influence of different parameters on the transmission characteristics of WPTD are analyzed. Finally, the theoretical model is validated by prototype performance tests. The results show that the loading mechanism demonstrates a good self-adaptive loading effect, and WPTD achieves a peak efficiency of 96%. Additionally, WPTD delivers superior efficiency and vibration and noise performance because of its smooth power-transfer characteristics, thereby providing a possible solution for high-speed and low-vibration transmissions.

A microwave transmitter/receiver using the low-temperature co-fired ceramic substrate and ball grid array packaging demonstrates superior properties, including high integration, miniaturization, and high electromagnetic shielding. However, it holds limitations of inadequate hermeticity (that is, gas or moist impermeability), high cost, and low reproducibility. In this work, we aim to overcome these difficulties by introducing a new packing technique. The packaging utilizes an electroless plated Ni/Pd/Au surface, resulting in a significant enhancement of the packaging hermeticity by orders of magnitude, approaching the level of <5 × 10−9 Pa·m3/s. Both Sn63Pb37 and Au80Sn20 solder alloys demonstrate exceptional solderability, attributed to Pd atoms diffusing to the Au layer during soldering at 310 °C. A reliability test of the packaging shows that the shear strength of the solder balls drops after thermal shocks but negligibly affects the hermeticity of the packaging. Furthermore, a meticulously designed internal vertical interconnect structure and I/O interconnections were engineered in the ball grid array packaging, showcasing excellent transmission characteristics within the 10–40 GHz frequency range while ensuring effective isolation between ports. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) technology has been popularized due to its convenience, safety, and unmanned nature. To improve the transmission performance of couplers and reduce the magnetic field, the designers of such couplers often adopt a combination of coils and substrates: however, the non-ferromagnetic substrate often leads to the enhancement of coil equivalent resistance and the decrease of the efficiency of a WPT system. In the present work, the effect of a substrate on coil equivalent resistance is evaluated by finite element simulation. The effects of the distance between a substrate and a coil and the number of turns of coil on the equivalent resistance of coils are studied. Based on the calculation method of alternating current resistance for Litz-wire, the equivalent resistance reduction method involving use of a coil with substrates is proposed to significantly reduce equivalent resistance of the coil with its substrate. A high-power-density coupler is designed based on the above method. The power densities of a transmitting coil and a receiving coil are only 0.542 W/cm 3 and 0.81 W/cm 3 respectively. When the transmission distance is 200 mm, a power transmission of 3.61 kW is realized, and the efficiency of the coupler and system reaches 94.61% and 92.56%, respectively. • The more coil turns, the greater effect of non-ferromagnetic substrate on resistance. • The change of substrate size will significantly affect the coil equivalent resistance. • The mutual inductance of coupler with substrate hardly affects the coil equivalent resistance. • Increasing strand number of Litz wire significantly reduce coil resistance with NFMS. • The proposed coupler structure achieves high power density and high efficiency. [ABSTRACT FROM AUTHOR]

Due to the complex material and shape of synchronous belt, it has complex mechanical behavior in normal operation. To solve this problem, propose a matrix model to calculate the tangential pressure of the meshing part between tooth and pulley. In the matrix model, use spring to replace the contact between synchronous belt and pulley, synchronous belt was discretized and separated into independent parts. In order to verify the model correctness, multi-body dynamics software RecurDyn was used to simulate the synchronous belt transmission system. The results show that the calculated results is closed to simulation results at the beginning and the end of the meshing part where the tangential pressure is larger, and there are some difference in the meshing part where the tangential pressure is smaller. Comparing with other methods, the matrix model has less computation, which solves the difficulty of calculating the tangential pressure of the belt, and provides a theoretical basis for the selection and design optimization of synchronous belt.

In order to study the factors affecting the transmission performance of the steering gear used in agricultural intelligent cars, a small steering gear model is established by RecurDyn. Within the allowable range of the circumferential backlash of each gear group, the changes of different circumferential backlash are obtained by adjusting the tooth thickness of the gear group. The simulation of acceleration, deceleration and forward and reverse rotation of the steering gear model shows that when the circumferential backlash is 0.130 mm, the accuracy of the output gear 8 of the steering gear is relatively high and the return error is small. This research provides a theoretical basis for solving the driving accuracy problem of a smart car.

The flexspline (FS) of the harmonic drive (HD) is subjected to thermal load and force load during operation, leading to the deformation difference between the inner and outer surfaces of the FS. As a result, the transmission performance of the HD assembly decreases. To overcome this problem, the thermal–mechanical coupling deformation mechanism of the FS is analyzed, and then the influence of the deformation difference on the transmission accuracy of the HD is studied in this article. On this basis, the structural parameters of the wave generator are optimized to eliminate actual backlash and to improve the actual transmission accuracy. Finally, the effectiveness of the calculation method proposed in this article was proved by the prototype test.

In this paper, the authors present the results of a set of measurements carried out to analyze the transmission capabilities of the LoRaWAN technology for underwater to above water transmission in saline water. A theoretical analysis was used to model the link budget of the radio channel in the considered operative conditions and to estimate the electrical permittivity of salt water. Preliminary measurements were performed in the laboratory at different salinity levels to confirm the application boundaries of the technology, then field tests were conducted in the Venice lagoon. While these test are not focused on demonstrating the usability of LoRaWAN to collect data underwater, the achieved results demonstrate that LoRaWAN transmitters can be used in all those conditions when they are expected to be partially or totally submerged below a thin layer of marine water, in accordance with the prediction of the proposed theoretical model. This achievement paves the way for the deployment of superficial marine sensor networks in the Internet of Underwater Things (IoUT) context, as for the monitoring of bridges, harbor structures, water parameters and water sport athletes and for the realization of high-water or fill-level alarm systems. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: In magnetically resonant wireless power transfer (MR‐WPT) systems, transmitter, and receiver usually operate at the same resonant frequency. However, parameters of inductor, capacitor, or other components are susceptible to changes due to environmental factors and cause resonant frequency deviation. This would lead to decrease of transmission performance. To solve the problem, a wireless power transfer system based on a nonlinear compensation network is proposed to suppress frequency offset. The modeling of the nonlinear MR‐WPT system is first established. On this basis, the mathematical equation of the equivalent nonlinear circuit is deduced and the amplitude‐frequency response characteristics are analyzed. The influence of inductance parameter on the nonlinear characteristic is studied. Furthermore, the effects of excitation amplitude, compensation capacitance, load, and magnetic ring turns on the operating characteristics of the nonlinear resonant circuit are analyzed. The proposed nonlinear resonant wireless power transfer system is constructed and is experimentally studied. Compared with the traditional linear MR‐WPT system, the results show that frequency offset can be effectively suppressed, which ensures efficient transmission performance with the proposed method. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In terms of high-speed optical access system, an optical access network system with low-cost and low-complexity based on PAM8 modulated signal is proposed to meet the growing demand of optical access network capacity. Based on the system scheme proposed, an experimental simulation platform of 10 Gbit/s PAM8 modulated signal optical access system is built. In this scheme of the system, the intensity modulation/direct detection (IM/DD) is used to achieve the modulation and demodulation of the signal, and the entire optical access link does not use additional signal amplifier components, reducing the complexity and cost of the system. According to the experimental results, the BER of the received signal has slight changes within a certain transmission distance. And after 20 kilometers of transmission, when the BER of the received signal is close to 1e-4, the receiving sensitivity is lower than - 12 dBm. The proposed optical access system has good sensitivity and has good application prospects for future broadband access network. [ABSTRACT FROM AUTHOR]

To fit with a digital environment in networked control systems, sampled-data event-triggered control (ETC) has been proposed where the event-triggering mechanisms sense and process information only at discrete sampling instants (not necessarily periodically). One deficiency in the previous study on sampled-data ETC is the lack of analysis on transmission performance, which yields the potential occurrence of an undesirable phenomenon that the minimum inter-event time is always equal to the minimum inter-sampling interval, no matter how small the latter is. To overcome this drawback, in this paper, we propose a novel sampled-data ETC scheme such that the lower bounds of inter-event times have sampling-independent positive guarantees. A linear networked control system is considered under observer-based controllers, external disturbances, and multiple communication channels. The improved transmission performance is due to the utilization of dynamic event-triggering conditions and some mean-rate error signals, which are the ratios between network-induced errors and some time-increasing functions. After modeling the closed-loop dynamics into a hybrid system, sufficient conditions on the upper bound of inter-sampling intervals and parameters in ETC are provided to ensure input-to-state stability (rather than its practical version) and sampling-independent positive guarantees simultaneously. Furthermore, a new tradeoff relationship between the sampling and transmission performance is revealed: a faster sampling frequency is conducive to improving inter-event times. Finally, a linearized model of an inverted pendulum is simulated to illustrate the efficiency and feasibility of the obtained results. [ABSTRACT FROM AUTHOR]

In order to solve the electrical performance limitations of horizontal multilayer graphene nanoribbon (H-MLGNR) based interconnect, a new geometric structure of vertical multilayer graphene nanoribbon (V-MLGNR) based interconnect is proposed in this paper. A numerical model for H-MLGNR and V-MLGNR based interconnects is established to investigate the performance in time and frequency domain, where the high-k dielectric materials (HKDM) are introduced for improving their transmission performance. The computation results demonstrate that the delay time for H-MLGNR and V-MLGNR based interconnects with embedded BaTiO 3 –Ni case can be reduced over 89.601 % and 93.723 % in comparison to the original H-MLGNR and V-MLGNR based interconnects, respectively. The corresponding 3-dB bandwidth for them can be expanded over 1.928 and 2.957 times, respectively. Moreover, it is manifested that the delay time of V-MLGNR based interconnect for the original, embedding the HfO 2 , TiO 2 , SrTiO 3 , BaTiO 3 , 6.0 vol% BaTiO 3 –Ni and 12.0 vol% BaTiO 3 –Ni cases can be reduced over 11.644 %, 13.269 %, 16.851 %, 22.311 %, 27.589 %, 33.608 % and 46.556 % as compared with the conventional H-MLGNR based interconnect, respectively. Meanwhile the corresponding 3-dB bandwidth of the former for the original, embedding the HfO 2 , TiO 2 , SrTiO 3 , BaTiO 3 , 6.0 vol% BaTiO 3 –Ni and 12.0 vol% BaTiO 3 –Ni cases can be enhanced over 1.113, 1.126, 1.155, 1.207, 1.266, 1.366 and 1.737 times as compared with the latter, respectively. In addition, the signal integrity of the proposed V-MLGNR based interconnects with embedded HKDM is greater than H-MLGNR based interconnects, while the power consumption of the former is slightly higher than the latter. Therefore, the proposed new interconnect structure concerning the V-MLGNR with embedded HKDM would be rewarding to enhance transmission performance of interconnect system in VLIS circuits. • The equivalent circuit model is established to investigate the transmission performance of H-MLGNR and V-MLGNR based interconnects in time and frequency domain. • The high-k dielectric materials (HKDM) are introduced for reducing propagation delay and expanding 3-dB bandwidth of H-MLGNR and V-MLGNR based interconnects. • The performance advantage of new geometric structure of V-MLGNR based interconnect over the conventional H-MLGNR based interconnect are demonstrated. • The proposed new technology concerning the V-MLGNR with embedded HKDM can effectively improve transmission performance of MLGNR based interconnects. [ABSTRACT FROM AUTHOR]

A microwave transmitter/receiver using the low-temperature co-fired ceramic substrate and ball grid array packaging demonstrates superior properties, including high integration, miniaturization, and high electromagnetic shielding. However, it holds limitations of inadequate hermeticity (that is, gas or moist impermeability), high cost, and low reproducibility. In this work, we aim to overcome these difficulties by introducing a new packing technique. The packaging utilizes an electroless plated Ni/Pd/Au surface, resulting in a significant enhancement of the packaging hermeticity by orders of magnitude, approaching the level of −9 Pa·m3/s. Both Sn63Pb37 and Au80Sn20 solder alloys demonstrate exceptional solderability, attributed to Pd atoms diffusing to the Au layer during soldering at 310 °C. A reliability test of the packaging shows that the shear strength of the solder balls drops after thermal shocks but negligibly affects the hermeticity of the packaging. Furthermore, a meticulously designed internal vertical interconnect structure and I/O interconnections were engineered in the ball grid array packaging, showcasing excellent transmission characteristics within the 10–40 GHz frequency range while ensuring effective isolation between ports.

The technology in which low-voltage power lines are used as communication channels is a hot spot in current information transmission research. Signal transmission on 220 V/380 V low-voltage power lines is quite different from high-voltage power line carrier communication. It is characterized by low line impedance, strong signal attenuation, large interference, and large time-varying characteristics. In this paper, we apply the ant colony algorithm to low-voltage power line carrier communication signal transmission, and the characteristics of conventional low-voltage power line channels and the test results based on the ant colony algorithm are analyzed. The research results show that noise interference usually has multiple noise sources, and the power line attenuation is usually above 20 dB. The attenuation increases with the increase of frequency. Because the load presents different properties to the power line, it may attenuate greatly at certain frequencies. The attenuation amplitude is the largest when it is less than 100 kHz, and the attenuation amplitude becomes relatively stable when it is greater than 500 kHz. The longer the signal transmission distance, the more severe the signal attenuation, so the signal transmission distance is usually not higher than 1 000 m. Ant colony algorithm can effectively improve the transmission performance of low-voltage power line carrier communication signals, and it can well overcome different types of noise interference. [ABSTRACT FROM AUTHOR]

Wire bonding is widely used in various radio frequency (RF) devices and is one of the common forms of signal interconnection. In this article, a new geometric model with related physical parameters is used to describe various actual types of the bondwire, and the corresponding calculation method for the total length of the bondwire is obtained. Consequently, a new equivalent circuit modeling method of the single‐bondwire can be developed and the accuracy of model has been improved. On this basis, using the concept of partial inductance, the modeling method of double‐bondwire is proposed, which can be applied to asymmetric double‐bondwire modeling. The model of bondwire obtained by this modeling method is applied to the design of PA, and the special electrical properties of the bondwire are used to verify a novel harmonic control method, which second and third harmonics could be controlled. The results show that in the Sub‐6G, the proposed bondwire model has good accuracy, and its performance is close to the measured results. The designed PA combined with harmonic control network has good performance, achieving drain efficiency of 62.6%–70% and output power of 40–41.5 dBm at 3.2–3.8 GHz. It is proved that the proposed bonding line modeling method can be applied to the design of high‐efficient PA. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To solve the problems of complex structure, poor reliability, and low intelligence of existing fan clutches for large hybrid vehicles, this paper proposes a new adaptive shape memory alloy intelligent fan clutch for large hybrid vehicle motor cooling. Based on the pure shear shape memory alloy thermodynamic effects, the relationship between shape memory alloy spring recovery force and temperature has been established; based on the shape memory alloy spring thermal drive characteristics and clutch construction dimensions, clutch torque transmission equations have been established. The shape memory alloy fan clutch transmission characteristics were quantitatively analyzed in terms of temperature, torque, rotational speed, and slip rate. The results show that the shape memory alloy fan clutch model based on the finite element method (FEM) and the established transmission model can accurately describe the mechanical characteristics of the shape memory alloy phase change process and the clutch torque transmission characteristics. When the clutch input speed is 3000 rad/min and the temperature is 100 °C, the output torque is 19.04 N·m, the speed is 2877.2 rad/min, and the slip rate is 4.3%. Due to the shape memory effect of shape memory alloy, the clutch can intelligently adjust the fan speed by sensing the ambient temperature. A fan clutch can satisfy the heat dissipation requirement of a large hybrid vehicle's transmission system under complicated road conditions. [ABSTRACT FROM AUTHOR]

In this paper, the authors present the results of a set of measurements carried out to analyze the transmission capabilities of the LoRaWAN technology for underwater to above water transmission in saline water. A theoretical analysis was used to model the link budget of the radio channel in the considered operative conditions and to estimate the electrical permittivity of salt water. Preliminary measurements were performed in the laboratory at different salinity levels to confirm the application boundaries of the technology, then field tests were conducted in the Venice lagoon. While these test are not focused on demonstrating the usability of LoRaWAN to collect data underwater, the achieved results demonstrate that LoRaWAN transmitters can be used in all those conditions when they are expected to be partially or totally submerged below a thin layer of marine water, in accordance with the prediction of the proposed theoretical model. This achievement paves the way for the deployment of superficial marine sensor networks in the Internet of Underwater Things (IoUT) context, as for the monitoring of bridges, harbor structures, water parameters and water sport athletes and for the realization of high-water or fill-level alarm systems.

This communication presents a theoretical study that establishes the performance limits for a multilayer transmitarray unit cell. This is the first study to be applicable to unit cells in which the conducting resonators, on the different layers, are shaped differently. A theoretical calculation is derived at the beginning. The theoretical calculations predict that, for an S21 amplitude of −1 dB, unit cells having two and three conducting layers provide a phase shifting range of 170° and 360°, respectively. In addition, for a given phase shifting range of S21, a new methodology for analyzing the maximum S21 amplitude, based on different substrates, is proposed. For the first time, we prove that it is efficient to attain the maximum S21 amplitudes by employing a smaller substrate permittivity or a quarter-of-wavelength substrate electrical thickness. Finally, the theoretical calculations have been validated through computer simulation. [ABSTRACT FROM AUTHOR]

Copyright of Railway Signalling & Communication Engineering is the property of Railway Signalling & Communication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taking the reducer for robot as the research object，a reducer test device composed of drive system，mechanical system，control system and data acquisition system is developed to test its mechanical transmission performance. In the process of testing，because of the traditional test method is difficult to capture the instantaneous change of the data，this is not conducive to the study of precision gear reducer. In order to solve this problem，the solving method is put forward. The software system based on JUCE libraries is designed，combined with the movement control cards of data transmission，the performance test of speed reducer is finished. The results show that the test system can quickly and accurately measure the transmission performance of the reducer，and it is expected to analyze and optimize to improve the overall performance of the reducer.

In order to improve transmission performance of Wireless Power Transfer (WPT) system, this paper proposes the concept of optimal receiver radius. The planar square transmitter coil WPT system is studied to explore the variation rule of optimal receiver radius with the parameters of WPT system. The key parameters that affect optimal radius are transmitter coil turns, turn spacing, side length and transmission distance. On this basis, by introducing BP neural network to learn the variation rule, the accurate prediction of optimal receiver radius under different parameters is realized. Finally, the finite element simulation proves the existence of optimal receiver radius and the accuracy of the prediction value.

In this article, a dual-loop active shielding coil directly connected in series with the primary coil is proposed to reduce the leakage magnetic field while eliminating the additional coupling between the shielding coil and the receiving coil of a wireless electric vehicle (EV) charging system. Parameter design strategy featuring system efficiency improvement and shielding coil cost reduction using multi-objective optimization algorithm is proposed. Finally, a 1.5 kW with 19 cm air gap prototype is fabricated to verify the analytical results and investigate the influence of the shielding coil over the system parameters. The results prove that the proposed active shielding coil shows its advantage on the system transmission performance and the shielding effectiveness on the target surface comparing to conventional aluminum shielding. [ABSTRACT FROM AUTHOR]

Transmission networks are ubiquitous in modern society and play critical roles in facilitating the delivery and movement of information, power, and people between various locations. Robustness and transmission capacity are two pivotal and universal properties of practical networks, and much research effort has been devoted to investigating these two properties in the past decade. In this article, we consider a heterogeneous transmission network consisting of hosts and routers and aim to optimize both transmission capacity and robustness of this network simultaneously. To solve this problem, we propose a multiobjective evolutionary algorithm (MOEA) for optimizing transmission capacity and robustness. Moreover, in order to achieve optimized transmission performance and robustness at reasonable and balanced computational cost, the proposed MOEA adopts a two-phase design, i.e., a sampling phase and an optimization phase. Simulation results on scale-free and realistic transmission networks demonstrate the effectiveness of the proposed algorithm. Moreover, comprehensive analysis of the solutions from different parts of the obtained Pareto fronts shows distinct characteristics and provides various choices for optimizing transmission functionality and robustness of networks. [ABSTRACT FROM AUTHOR]

Aiming at the shortcomings of the traditional contact power supply mode, a low-power magnetic coupling resonant wireless power supply system was designed to study the transmission characteristics of the system. The circuit coupling theory is mainly used to establish the equivalent circuit model of the system. The influence of system parameters on the transmission characteristics, including the resonant frequency, load resistance and coupling coefficient, is simulated by MATLAB. Finally, a low-power wireless power supply system test platform is built. The transmission characteristics of the system were tested and verified. The transmission characteristic test results are in good agreement with the MATLAB simulation analysis results, indicating that the designed low-power magnetic coupling resonant wireless power supply system can perform good wireless energy transmission, and also provide new ideas for the development of low-power wireless charging equipment.

Optimal design parameter combination and transmission optimization for plane-generated enveloping toroid hourglass worm drive are proposed. The modeling frame and mathematical model of the worm were constructed first to provide a perfect transmission. Then, the mathematical representations of transmission performance, including lubrication angle, induced normal curvature, and length of meshing line for worm drive, were derived according to differential geometry and coordinate transformation approach. In addition, the influence of various design parameters on transmission performance was associated with main parameters, and the influence of the main parameters on transmission was evaluated. Next, a multivariate transmission optimization considering lubrication effect, bearing capacity and contact strength was conducted in view of the whole meshing cycle. The optimal global solution of the multivariate optimization model was also evaluated using a genetic algorithm. Calculation and experimental results indicated the optimization study was in good agreement with experimental results. Finally, the comprehensive transmission performance of the worm drive has an increase of 9.2 %. [ABSTRACT FROM AUTHOR]

To solve the problems of complex structure, poor reliability, and low intelligence of existing fan clutches for large hybrid vehicles, this paper proposes a new adaptive shape memory alloy intelligent fan clutch for large hybrid vehicle motor cooling. Based on the pure shear shape memory alloy thermodynamic effects, the relationship between shape memory alloy spring recovery force and temperature has been established; based on the shape memory alloy spring thermal drive characteristics and clutch construction dimensions, clutch torque transmission equations have been established. The shape memory alloy fan clutch transmission characteristics were quantitatively analyzed in terms of temperature, torque, rotational speed, and slip rate. The results show that the shape memory alloy fan clutch model based on the finite element method (FEM) and the established transmission model can accurately describe the mechanical characteristics of the shape memory alloy phase change process and the clutch torque transmission characteristics. When the clutch input speed is 3000 rad/min and the temperature is 100 °C, the output torque is 19.04 N·m, the speed is 2877.2 rad/min, and the slip rate is 4.3%. Due to the shape memory effect of shape memory alloy, the clutch can intelligently adjust the fan speed by sensing the ambient temperature. A fan clutch can satisfy the heat dissipation requirement of a large hybrid vehicle’s transmission system under complicated road conditions.

Automatic transmission has been widely used in the automotive industry, and novel automatic transmissions with simple structure and reliable operation are a research hotspot. This paper proposes an automatic transmission with multi-stage gears to simplify its working process. The automatic transmission comprises a case and a driving transmission shaft and driven shaft which are mounted on the case. The transmission gear pairs are superimposed on the driving and driven shafts similar to a tower. The gear pairs on the driving and driven shafts are always engaged. All the driving gears are connected to the driven shaft via a flat key, and the driven gear and the driven shaft are connected by a join key, which is used to connect or disconnect the gear and the driven shaft, and are controlled by a hydraulic shifting mechanism and have been designed in detail. Numerical simulation is adopted to verify the strength of the core components. In addition, the transmission performance of the gearbox is experimentally tested. The results indicate that the novel gearbox can achieve variable speed and work smoothly. The gearbox has a novel structure, the driving and driven shafts are simple and installed friendly, and the transmission gear meshes are reliable. [ABSTRACT FROM AUTHOR]

In order to study the transmission performance and performance comparison of two kinds of structure squirrel-cage and compound solid type of drum-type adjustable speed permanent magnetic asynchronous couplers,the aim is to improve the transmission efficiency and power of permanent magnetic asynchronous couplers in different applications. Firstly,through finite element calculation,the effects of squirrel cage rotor slot parameters on transmission torque and starting torque of squirrel cage permanent magnetic asynchronous couplers and the effects of copper thickness on transmission torque and efficiency of compound solid type permanent magnetic asynchronous couplers are respectively discussed. Then,contrastive analyses of mechanical characteristics,temperature and adjustable speed characteristics for two magnetic coupling with the same structure parameters are carried out. The results indicate that the squirrel-cage permanent magnetic asynchronous couplers can provide higher output torque at high speed and can operate in higher output speed and transmit higher output power.

The FT pin-cycloid reducer and RV reducer are new type of pin-cycloid transmission reducer with closed two stage transmission. The both type of reducer has the advantages of more compact structure,high rigidity,low vibration,high efficiency of low speed operation zone and so on. The structure of the two is similar in transmission mode,and the transmission performance is greatly improved compared with the previous generations of reducer and the transmission efficiency is also greatly higher. The FT455-81 prototype and RV-160 E-81-B-B prototype are taken as examples to compare the performance,price and other aspects.The 3D model of the FT and RV reducers is built. Its transmission principle,transmission characteristics and structure are analyzed and compared. The advantages and disadvantages of RV reducer and FT reducer are expounded. The suitable for application of the two reducer is found.

With the growing study on the active distribution network, an objective and efficient reliability evaluation method for such cyber-physical systems (CPS) is urgently needed. In this paper, first considering the cyber transmission performance, a new method is proposed for efficient evaluation of cyber link validity based on frequency-time domain transformation. In order to quantify the indirect interdependencies of cyber failures, an unresponsiveness probability model for switches is established. Then, an innovative method is proposed by combining the equivalent method and the minimal path method. Finally, a test system is established to verify the effectiveness of the proposed method. This study is instrumental in informing the efficient planning of contemporary CPS-based distribution networks. [ABSTRACT FROM AUTHOR]

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Although expendable conductivity–temperature–depth (XCTD) profiler has been extensively studied, there are relatively few studies on the transmission performance of XCTD channel, which makes it unclear that the signal is affected by the channel in the long-distance transmission process. First, the structure of the XCTD is analyzed. Then, according to the working mode and channel structure characteristics of XCTD, the circuit model of the transmission channel is established. In order to better study the channel compensation method, a laboratory transmission system of XCTD is built. By analyzing the influence of channel impedance parameters on the transmission signal, the channel model of XCTD is optimized, and the compensation channel is determined to be series inductance. Finally, the bit error rate (BER) of unoptimized and optimized channels is compared based on ASK and differential phase-shift keying (DPSK) modulation. It is verified that the optimized channel model of XCTD has a certain significance in reducing the BER of the transmission signal. This article has important theoretical significance and practical application value for the research of transmission signal transmission performance of expendable profiler. [ABSTRACT FROM AUTHOR]

Refractory lining is an indispensable part of high temperature microwave heating equipment, and its wave transmission performance exerts an important impact on the mode and efficiency of microwave heating, while the complex dielectric constant (dielectric constant and dielectric loss) of the material is the decisive factor in determining the wave transmission performance of the material. In this work, we measured the complex dielectric constant of polycrystalline mullite fiber board (PMF) in the temperature range of 25–1000 °C, and the effect of temperature on dielectric constant and dielectric loss was analyzed; The wave-transmission properties of the material were calculated according to the theory of electromagnetic wave transmission line, and the effects of temperature, material thickness, polarization modes of electromagnetic wave and incident angle on the wave transmission performance were analyzed. The results reveal that the dielectric constant of PMF does not change much with the increase of temperature, which is about 1.6; The dielectric loss does not change much within 200 °C, but when the temperature is higher than 200 °C, the change presents approximately exponential increase with the rise of temperature. The wave transmission performance fluctuates with the increase of the thickness, and there are maximum value and minimum value, and the overall wave transmission performance decreases with the increase of the material thickness. In a transverse electric (TE) field, the overall wave transmission performance decreases with the increase of the incident angle, and better wave transmission performance can be obtained by priority selection of vertical incidence of electromagnetic wave. In a transverse magnetic (TM) field, with the increase in the incident angle, the wave transmission performance firstly climbs up then declines, and there is an optimal incident angle where total transmission can occur. Finally, this work selected the thickness corresponding to different temperature as the preferred thickness. This work is of important theoretical significance for understanding the mechanism of the dynamic change of the wave transmission performance of the thermal insulation materials in microwave heating, and provides important practical guidance for the design and optimization of microwave heating equipment. [ABSTRACT FROM AUTHOR]

To solve the problem of static pressure transmission performance of electronic hydraulic brake system, the mathematical models of main cylinder, solenoid valve, accumulator, and motor hydraulic pump of electronic hydraulic brake system are established. Based on the mathematical model, the static pressure transmission performance of electronic hydraulic brake system is analyzed. Then the standard normal state model of static pressure transmission performance of electronic hydraulic brake system is established by statistical method. The threshold correlation degree between the vibration signal of the static pressure drive and the normal state mode obtained by the vibration acceleration sensor are calculated. If the threshold correlation degree is greater than or equal to 0.5, the precision pressure transmission state of the electronic hydraulic brake system to be tested belongs to the standard normal state, and the threshold correlation degree is less than 0.5, indicating that the precision pressure transmission state of the electronic hydraulic brake system to be tested does not belong to the standard normal state. The test results show that the proposed method can effectively detect the boost response of the static pressure transmission of the electronic hydraulic brake system under high and low strength conditions under normal conditions and accumulator failure conditions. The method can effectively detect the static pressure transmission state of the electronic hydraulic brake system belongs to the fault state according to the threshold correlation degree, which is consistent with the simulation results. [ABSTRACT FROM AUTHOR]