Search

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 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 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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

Refractory materials are an important part of industrial microwave heating equipment, and their transmission performance has a significant influence on the efficiency and uniformity of microwave heating. In this study, electromagnetic wave power transmission coefficients (PTCs) of alumina refractory ceramics are calculated within the temperature range of 22–1379 °C and the thickness range of 0–0.1 m at 2.45 GHz, and the influences of the complex dielectric constant of the material, the thickness of the medium, the polarisation mode of the electromagnetic waves, and the incident angle of the electromagnetic waves on PTC are analysed. It was found that the transmission performance of alumina ceramics fluctuates with increasing thickness at different temperatures and that there are several transmission peaks. The transmission performance in a transverse electric (TE) field decreases monotonically with increasing incident angle, and the PTC is equal to zero when the incident angle is 90°. The transmission performance in a transverse magnetic (TM) field increases first and then decreases with increasing incident angle, and there is a transmission peak. Transmission peaks at different thicknesses form a 'ridge' at the Brewster's angle, at which the fluctuation amplitude of PTC becomes very small. As the temperature increases, the 'ridge' becomes steeper. Finally, the incident angle range with good transmission performance of alumina ceramics in the temperature range of 22–1379 °C is obtained, and the optimal thickness interval at the optimum incident angle (73.8°) is calculated for reference. This research has important guiding significance for the selection and optimisation of refractory ceramic materials for use in microwave high-temperature heating. [ABSTRACT FROM AUTHOR]

• Transmission performance indices are introduced for planar higher pair mechanisms. • Contact closure index is proposed to identify the contact property. • Singularity of planar higher pair mechanisms is revealed. • Performance mapping onto geometric profiles is provided. • Equivalent higher pair mechanism is presented based on profile synthesis. Comprehensive and accurate evaluation of performance is essential for profile synthesis and profile analysis of higher pair mechanisms. Aiming at the transmission performance of planar higher pair mechanisms, the evaluation indices and methods are proposed from different perspectives. On the one hand, the kinematic performance indices in lower pair mechanisms are extended to higher pair mechanisms, including the mechanical advantage and the generalized pressure angle. On the other hand, novel indices specific to higher pair mechanisms are developed, including the contact closure index and the singularity distance index. Considering the performance of individual elements and that of the overall joint, the transmission performance of higher pairs is subdivided into element-based performance and joint-based performance, and the evaluation indices are classified accordingly. A graphical mapping method based on element-based performance is further proposed for intuitive analysis and qualitative evaluation. Practical examples validate the effectiveness of the proposed indices and methods for evaluating the performance of higher pair mechanisms, as well as their potential to enable optimal profile solution selection and design in the profile synthesis process. [ABSTRACT FROM AUTHOR]

• A low-loss and robust PEEK Ag/AgI hollow optical fiber was proposed and fabricated for delivering mid-infrared CO 2 laser radiation. • Flexible Poly ether ether ketone (PEEK) tubing material was selected as the waveguide structural tube and plasma treatment was used to enhance the laser transmission reliability of the hollow optical fiber. • The as-prepared PEEK Ag/AgI hollow fiber was low-cost, low-loss, flexible and reliable and could be potentially used in practical applications such as CO 2 laser medicine, intelligent manufacturing and sensing. Hollow fiber is a crucial means for delivery of mid-infrared laser radiation and has a wide range of applications in laser surgery and other fields. At present, there is still a lack of low-cost, highly flexible plastic hollow fiber that can reliably transmit mid-infrared laser with low loss. In this study, flexible Poly ether ether ketone (PEEK) tubing material was selected as the structural tube for establishing a robust plastic Ag/AgI mid-infrared hollow fiber. Fiber samples with inner diameters of 1.0, 1.5 and 2.0 mm were prepared using plasma treatment and dynamic chemical liquid deposition processes. The transmission losses for CO 2 laser of the 1.0-, 1.5- and 2.0-mm-bore PEEK Ag/AgI hollow fibers increased from 0.40, 0.18 and 0.10 dB/m to 2.35, 1.60 and 1.05 dB/m, respectively, as they were bent at an angle from 0° to 180° with a radius of 15 cm. The hollow fibers could stably transmit CO 2 laser in high (120 °C) and low (-78.5 °C) temperature environments. After undergoing 100 h of accelerated humidity-heat aging (85 °C, 85 % RH) and 10 cycles of high-low (-40 ∼ 85 °C) temperature cycling treatment, the transmission loss remained almost unchanged. The PEEK Ag/AgI hollow fiber exhibited high energy damage threshold and it could stably deliver a 10 ∼ 20 W CO 2 laser beam for 20 min to 5 h when bent at a 25 cm radius and a 90° angle. The current research provides a possible approach for developing low-cost, highly flexible, low-loss and highly reliable mid-infrared hollow fibers. It is helpful to promote the applications of CO 2 laser in laser medicine, intelligent manufacturing and sensing. [ABSTRACT FROM AUTHOR]

In this paper, a bandpass frequency selective surface (FSS) based on substrate-integrated waveguide (SIW) technology is presented for airborne radome application. The proposed FSS element consists of a tapered cross-slot on either side of the substrate surrounded by metallic vias. The structure selectively allows the impinging electromagnetic (EM) wave through it in the specified frequency band. The element shows very stable frequency response for oblique incidence and the sharp roll-off performance characteristics at the edges of operating region in the rejection band. The −10 dB relative bandwidth (BW) of the element is 12.8% from 9.5 to 10.8 GHz with a very good insertion loss (IL) of 0.1 dB. Furthermore, the spectacular advantages of the FSS element based on SIW have been used for modeling the airborne radome application. The proposed radome structure is operating at 10 GHz with a relative 10 dB BW of 25.0% (8.20–10.6 GHz) with maximum (IL) better than 0.1 dB in its passband. The behavior of the FSS radome has been analyzed at different conformal sectors and thickness is optimized for optimal performance. The key parameters of radome such as transmission performance, radiation efficiency, and radar cross section (RCS) have been studied. Experimental verifications are carried out to prove the validity of the estimated results. The results show promising performance of the proposed FSS based on SIW technology for airborne radome application. [ABSTRACT FROM AUTHOR]

In this study, the authors propose a new precoding‐aided spatial modulation (SM) to improve the transmission performance over significantly high correlated indoor multi‐input multi‐output visible light communication (MIMO‐VLC) channels. Especially, their precoder design relies on the fixed‐sized light‐emitting diode (LED) grouping and transmit beamforming, which plays an important role in enhancing the system performance. First, they propose an approximate discrete‐input continuous‐output memoryless channel capacity based precoder design, which offers better performance at the cost of high‐computational complexity. As far as large‐scale MIMO‐VLC schemes are considered, the proposed precoder design presents to be impractical. Therefore, they develop a spatial correlation measure‐based fast LED grouping algorithm to construct the precoder for large‐scale MIMO‐VLC systems. Their simulation results show that the proposed precoding‐aided SM scheme can outperform the precoding‐aided spatial multiplexing over significantly high correlated large‐scale MIMO‐VLC channels when the proposed fast LED grouping is performed, whereas the latter scheme can perform better than their proposed scheme for less correlated channels. [ABSTRACT FROM AUTHOR]

This Letter proposes a high data rate optical transmission system for data centre interconnects, where the authors employ vertical cavity surface emitting lasers (VCSEL) and graded index few‐mode fibre (GI‐FMF) having modal bandwidth of around 24.3 GHz.km to enhance the link capacity and range. Additionally, they consider PAM‐4 modulated data transmission at the rate of 2 × 100 Gbps using a pair of VCSELs and employing mode group division multiplexing of two linearly polarised (LP) modes LP01 and LP11 of the GI‐FMF. Digital signal processing techniques are applied at the receiver to process the received PAM‐4 signals for equalisation in order to mitigate the channel impairments. Furthermore, standard OM3 and OM4 fibres are considered as a benchmark to compare the transmission performance of the designed GI‐FMF. They observe that the designed GI‐FMF supports longer transmission distance for both LP01 and LP11 modes upto 900 and 450 m at 50 and 100 Gbps data rates, respectively, while achieving lower receiver sensitivities for forward error correction limit of 3.8×10−3. The proposed optical transmission system can be a potential applicant in future data centre networks supporting transmission rates in 800 Gbps to 1.6 Tbps range. [ABSTRACT FROM AUTHOR]

Rotary transformer has gradually become used in rotary ultrasonic machining device for power transmission. Compared with contact power transmission, such as slip ring, the contactless power transfer system makes it possible to transmit power without friction, abrasion, vibration and heat. However, in rotary ultrasonic grinding, the varieties of temperature and mechanical load will greatly impact the transmission performance of the contactless energy transfer circuit. This study presents a simple mathematical model of four circuit compensation topologies, which is applicable for non‐ideal condition, and explores the transmission efficiency, output power, and voltage of compensation elements under different temperature and mechanical loads based on this model. The optimal compensation method for the rotary ultrasonic grinding is determined by comparison. [ABSTRACT FROM AUTHOR]

• Study the influence of mode selection. It was shown that when LP 12 mode was multiplexed with LP 01 , LP 11 and LP 02 , the Q factor of the signal carried by LP 12 was 5-higher than that of LP 21 multiplexed with the three modes in the same system. • Study the influence of MMF core radius, the simulation results show that the optimum value of the GI-MMF core radius was 21 μm ∼ 22 μm. • The designed HMWDM system is scalable for both wavelengths and modes. The choice of linear polarization modes in optical fiber is a key factor affecting performance of mode division multiplexing system (MDM). Firstly, an intensity modulation and direct detection (IM-DD) optical fiber transmission system based on hybrid mode division and wavelength division multiplexing (HMWDM) is designed. Secondly, the transmission characteristics of LP 01 , LP 11 , LP 02 , LP 12 and LP 21 five modes in the HMWDM system are simulated by Optisystem15.0 software. It was shown that when LP 12 mode was multiplexed with LP 01 , LP 11 and LP 02 , the Q factor of the signal carried by LP 12 was 5-higher than that of LP 21 multiplexed with the three modes in the same system. Then, four modes of LP 01 , LP 11 , LP 02 and LP 12 are multiplexed, and the simulation results show that the optimum value of the Graded-index multimode fiber (GI-MMF) core radius was 21 μm ∼ 22 μm with the Q factor above 7 when the core radius changed from 19 μm to 25 μm. Furthermore, the optimal value does not change with the transmission distance and the bandwidth of de-multiplexer. Finally, in the HMWDM system with a 21 μm-optimal-value core radius, the IM-DD method was used to realize the short distance transmission at 2.0 km with bit error rate (BER) below 10−9 and a rate of 80Gbit/s. The extension of the HMWDM system also be proposed. [ABSTRACT FROM AUTHOR]

Empty substrate integrated waveguide (ESIW) is a hollow SIW with its inner dielectric removed to achieve a reduced insertion loss. One of the drawbacks is the top and bottom covers need to be soldered to the middle substrate. Gap waveguide (GW) technology solves the contact issue utilising contactless electromagnetic band‐gap (EBG) structures. Therefore, empty substrate integrated GW (ESIGW) is a transmission line having both advantages of ESIW and GW. In this Letter, a wideband transition from rectangular waveguide (RW) to ESIGW is presented. RW is firstly matched to reduced‐height RW using E‐plane stepped waveguides. Then, a short substrate integrated GW (SIGW) section is introduced between the reduced‐height RW and the ESIGW. This section not only serves as an impedance matching component, it also connects the two sides of the ESIGW and maintains the integrity of the substrate. To broaden the bandwidth of the transition, a triangular dielectric is added at the end of the ESIGW. A Ka‐band back‐to‐back prototype of the transition is designed and fabricated. In addition, TRL calibration is used to measure the transmission performance of the ESIGW. The measured results show that the transition works well over the entire Ka‐band. [ABSTRACT FROM AUTHOR]

A 1 × 16 capacitive micro-machined ultrasonic transducer linear array was designed, fabricated, and tested for underwater imaging in the low frequency range. The linear array was fabricated using Si-SOI bonding techniques. Underwater transmission performance was tested in a water tank, and the array has a resonant frequency of 700 kHz, with pressure amplitude 182 dB (μPa·m/V) at 1 m. The -3 dB main beam width of the designed dense linear array is approximately 5 degrees. Synthetic aperture focusing technique was applied to improve the resolution of reconstructed images, with promising results. Thus, the proposed array was shown to be suitable for underwater imaging applications. [ABSTRACT FROM AUTHOR]

As a typical surface strengthening method, shot peening can effectively enhance the bending fatigue resistance of spiral bevel gears by improving the surface integrity parameters. Due to the complex geometry of spiral bevel gears, one group of shot-peening parameters can hardly satisfy the performance requirements of concave and convex surfaces. Thus, the effect mechanism of shot peening on both surfaces needs a thorough understanding. Meanwhile, the effect of shot peening on the transmission performance of gears is still somewhat cloudy and controversial, which confuses the optimization of shot-peening parameters. To address this issue, the effect of shot peening on the surface integrity and transmission performance of spiral bevel gears is systematically investigated by experiments. The results show that due to the smaller curvature radius, the surface integrity of the concave surface is better than that of the convex surface before and after shot peening. Specifically, for the shot-peened gears, the dislocation density at the concave surface is 9.1 % higher than that at the convex surface; the intergranular oxidation (IGO) layer for the concave surface is 2.1 % shallower than that for the convex surface; the maximum compressive residual stress for the concave surface in the profile direction is 6.9 % higher than that for the convex surface; the peak value of hardness for the concave surface is 3.5 % higher than that for the convex surface. Furthermore, smoother tooth flanks can lead to better transmission performance of gears, and shot peening has side effects on it. The transmission performance in the drive condition is better than that in the coast condition before and after shot peening. • The concave surface of the spiral bevel gear with a smaller curvature radius exhibits better microstructural characteristics. • The concave surface of the spiral bevel gear with a smaller curvature radius shows better mechanical properties. • The transmission performance of spiral bevel gears in the drive condition is better due to the smoother drive surfaces. [ABSTRACT FROM AUTHOR]

Absolute added correlative coding with eight levels has been proposed and demonstrated numerically at bit rates of 30 and 60 Gbps back‐to‐back, and up to 75 Gbps over 2000 and 3000 m standard single‐mode fibre using a single‐drive multiple quantum‐well Mach–Zehnder modulator. The transmission performance is compared with the conventional eight‐level pulse amplitude modulation. [ABSTRACT FROM AUTHOR]

The forwarding ability of encountering node has not been considered by spray and wait mechanism. This paper proposed an adaptive routing algorithm based on nodes’ transmission performance, named TP-ASW, to overcome the blindness and random of relay nodes selecting. TP-ASW thought over synthetically the factors of node’s energy and neighbors’ changing and adaptively controlled the data forwarding condition due to the similarity of encountering nodes’ neighbors list. The simulation results show that TP-ASW achieves higher delivery probability and prominently lower overhead. [ABSTRACT FROM AUTHOR]

Highlights: [•] An integrated sunlight transferring model formed by a dish and a window is set up. [•] The transmissivity of the windows was predicted by a Monte Carlo ray-tracing method. [•] The transmissivity of sapphire windows is 12.0% lower than that of quartz glass window. [•] Improving the dish performances can increase the transmissivity of the windows. [•] Influences of the window geometries on the transmissivity are slight. [Copyright &y& Elsevier]

Abstract: We studied both numerically and experimentally electromagnetic behaviors of a bilayered metal helical structure in the microwave-frequency. Two resonances are found in the transmission spectrum of the circularly polarized wave which has the same handedness with the helices. The resonance frequencies are almost independent on the distance between the two layers. In addition, the center frequency of full width at half-maximum (FWHM) in the transmission spectrum is approximately inversely proportional to the distance between the two layers. [Copyright &y& Elsevier]

With the rapid development of MEMS fabrication technology, the function of transferring motion and force for micro transmission mechanism has been basically implemented. The micro transmission mechanism could mainly be driven by micro actuators, through several transmission parts such as micro link, micro hinge and micro gear, to transfer motion and force. Research status and working principle of micro transmission mechanism in the recent twenty years are summarized in detail. Research status and research achievements about design and transferring motion are introduced. In addition, the key technology, existing problems and application prospect of micro transmission mechanism are analyzed. [ABSTRACT FROM AUTHOR]

For the requirement of broadband transmission with low attenuation within the radio frequency band, a topology optimization model of microstructure configuration design of patch-typed left-handed metamaterials is established, with the objective function defined by the ratio of the mean attenuation to the absolute left-handed bandwidth; then a genetic algorithm based solution method and flow chart of the topology optimization are presented. An improved electromagnetic simulation analysis method is used to obtain accurate equivalent electromagnetic parameters from the S-parameter retrieval process. Three patch-typed microstructure configurations are given according to the results of topology optimization designs for different lattice sizes, and the transmission performance indicators of these creative configurations are computed and analyzed by numerical simulation. The contrast of the design results shows that a U-shaped-like structure of half a unit cell height exists among all these optimum configurations. It is found through a further analysis that the distribution of conduction currents of U-shaped-like structures is the key to broadband transmission with low attenuation. Finally, a new topology optimization design with the perimeter constraint is proposed to solve the problem in the manufacturing process for checkerboard-typed lattices from these configurations. [ABSTRACT FROM AUTHOR]

Abstract: A novel radio-over-fiber (ROF) scheme simultaneously to modulate and transmit 10-Gb/s baseband and 60-GHz microwave signals on a single wavelength using single-sideband (SSB) modulation technique is proposed and verified by simulation. The scheme is based on a Dual-Parallel Mach-Zehnder Modulator (DPMZM). The scheme can carry the microwave signals on either the upper sideband (USB) or the lower sideband (LSB) only and the baseband signals on the other sideband. The optical 60-GHz millimeter wave (mm-wave) carrier is generated by means of subcarrier-multiplexing (SCM) technique to carry 155-Mb/s baseband signals while 10-Gb/s baseband signals are imposed on the original optical carrier via SSB modulation. The signals with dual services are successfully transmitted over 50-km single-mode fiber. [ABSTRACT FROM AUTHOR]

Abstract: Performance evaluation is one of most important issues in the analysis and design of parallel manipulators. As the counterparts of serial robots, parallel manipulators are mostly good at motion/force transmission but not dexterous manipulation. In this study, a generalized transmission index that can evaluate the motion/force transmissibility of fully parallel manipulators is proposed based on the virtual coefficient. The transmission index defined here is frame-free and is relative to singularity. By giving a specified and significant value, the index can be used to identify a good transmission workspace (GTW), where the parallel manipulator is not only good at motion/force transmission, but is also far away from its singularity. To introduce the analysis method and the frame-free index, the transmission performance analysis of two parallel manipulators is presented. The analysis method of motion/force transmissibility and the proposed index are expected to be applied to the analysis and kinematic optimal design of fully parallel manipulators. [Copyright &y& Elsevier]

The trade‐off between transmission performance and hardware implementation in application‐specific integrated circuits of digital backpropagation (DBP) in coherent 32 GBd polarisation‐division multiplexing 16 quadrature amplitude modulation is analysed. The reach is optimised for different DBP implementations under constraints of 16 and 28 nm complementary metal–oxide–semiconductor (CMOS) technology digital signal processing (DSP) area. [ABSTRACT FROM AUTHOR]

The design and experimental characterisation of a depolarised light source for feeding a remote transceiver based on silicon photonics are presented. Since the transceiver only works in TE mode, the source is designed to deliver, over up to 10 km standard single‐mode fibre links, a continuous‐wave light with almost constant power along this polarisation direction, whatever be the random polarisation rotation because of the fibre link. The depolarised light source is realised by combining the output of two independent distributed feedback lasers, having orthogonal polarisation and controlled frequency difference. The transmission performance and stability of the remote light source are successfully tested. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new scheme of digital frequency modulation that jointly utilizes a Nyquist III filter and a Gaussian filter for a premodulation filter. In this scheme, the phase transition and the phase trajectory during the symbol interval are settled independently of each other by setting the parameters of the two filters, and it is thus possible to improve the transmission performance by controlling the parameters of these filters appropriately. Furthermore, this scheme has an additional merit of increasing the minimum signal-space distance d2min above 2.0, and it has the possibility of improving BER performance. When the bandwidth of the signal widens with the increase of d2min, it is possible to adjust the signal spectrum by utilizing the Gaussian filter. Thus, it is possible to obtain superior transmission performance by setting the parameters of the two filters appropriately and employing a suitable detection method. Furthermore, we show that the transmission performance of this scheme is as good as GMSK in an AWGN environment. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 3, 80(9): 1–10, 1997 [ABSTRACT FROM AUTHOR]

This paper considers a function to improve the efficiency of the operation administration and maintenance (OAM) of the virtual path (VP) in the AIM network. A VP test method is proposed which can test the connectivity and performance at new VP establishment and locate the fault point at VP failure. The implementation of the method is discussed. The feature of proposed method is that the number of error bits, the number of lost cells, and the number of misdelivered cells can be measured by transmitting and receiving the test OAM cell in any test section of VP. In this piper, the purpose and requirements for the VP test system are described first. Then the mechanisms in the proposed system and the allocation of test functions are considered. A transmission performance measurement algorithm is proposed for the test OAM receiver so that the bit error, the cell loss, and the cell misdelivery can accurately be counted. The structure of the VP test OAM cell to realize the proposed algorithm is presented. Finally, the system parameters of the proposed method are evaluated quantitatively. [ABSTRACT FROM AUTHOR]

• A tolerance analysis method considering contact behavior for spur gears is proposed. • Both machining and assembly errors are considered based on skin model shapes. • Contact behavior is calculated using the boundary element method. • Notable effects of contact behavior on transmission performance are demonstrated. Tolerance analysis is an important approach for evaluating the accuracy and function of mechanical products. Research on tolerance analysis has mainly focused on the transfer and accumulation of geometric deviations during assembly, while the effects of contact behavior have not been considered in detail. Therefore, this paper presents a tolerance analysis approach to spur gears that takes into account the effects of contact behavior between mating tooth surfaces on transmission performance. Machining and assembly errors are represented based on the concept of skin model shapes. The contact behavior between mating tooth surfaces is calculated using the boundary element method (BEM) to perform tooth contact analysis (TCA). The proposed tolerance analysis approach is applied to a pair of spur gears as an example. The manner in which the transmission error, tooth contact pattern and contact pressure distribution are affected by machining and assembly errors is discussed. This research demonstrates the notable effects of contact behavior between mating tooth surfaces on transmission performance and provides a potential method for the tolerance analysis of other mechanisms. [ABSTRACT FROM AUTHOR]

A new type of tapered single capillary X-ray lens, which is manufactured by using the nesting method, is proposed to generate a small focal spot with high power density gain for micro X-ray analysis. Experimentally, it was found that the nested tapered single capillary has a good geometric shape, and the tubes nest well. The experimental results verify that the nested manufacture process is feasible. Moreover, the transmission performance of the nested tapered single capillary was measured in the laboratory. At a distance 1.5 mm from the exit of the nested tapered single capillary, a beam spot of 9.1 μ m was obtained. The transmission efficiency of the nested tapered single capillary was 55%, and the gain in power density measured with or without the nested tapered single capillary was 16. [ABSTRACT FROM AUTHOR]

By using the GeO2-NaOH precursor solution, the hexagonal structural GeO2 reflective films with high flatness were grown on the inner wall of stainless steel (SUS) capillary tubes by liquid phase deposition method. XRD and SEM were measured to investigate the structure and surface roughness of GeO2 films prepared with different precursor solution. Subsequently, the transmission losses were measured and calculated which revealed the transmission loss was only one third of previous value in the sample using the glass tube. Considering the processing technology limit of 1 mm-bore hollow waveguide, the output energy distribution of the 1.5 mm-bore sample approximates to Gaussian distribution which may excite the less high-order modes. Furthermore, the full divergence angles, bending loss and output power were further investigated. These results demonstrate that the transmission performance of the GeO2 SUS tube-based hollow waveguide can meet the requirements for laser surgery and material processing. [ABSTRACT FROM AUTHOR]