Search

Advanced silicon photonic technologies enable integrated optical sensing and communication (IOSAC) in real time for the emerging application requirements of simultaneous sensing and communication for next-generation networks. Here, we propose and demonstrate the IOSAC system on the silicon nitride (SiN) photonics platform. The IOSAC devices based on microring resonators are capable of monitoring the variation of analytes, transmitting the information to the terminal along with the modulated optical signal in real-time, and replacing bulk optics in high-precision and high-speed applications. By directly integrating SiN ring resonators with optical communication networks, simultaneous sensing and optical communication are demonstrated by an optical signal transmission experimental system using especially filtering amplified spontaneous emission spectra. The refractive index (RI) sensing ring with a sensitivity of 172 nm/RIU, a figure of merit (FOM) of 1220, and a detection limit (DL) of 8.2*10-6 RIU is demonstrated. Simultaneously, the 1.25 Gbps optical on-off-keying (OOK) signal is transmitted at the concentration of different NaCl solutions, which indicates the bit-error-ratio (BER) decreases with the increase in concentration. The novel IOSAC technology shows the potential to realize high-performance simultaneous biosensing and communication in real time and further accelerate the development of IoT and 6G networks., Comment: 11pages, 5 figutres

In this paper, a kind of fuel cell voltage monitoring (CVM) system with negative voltage direct detection function is proposed for the reverse polarity phenomenon of fuel cell stack. This system uses optocoupler relays array to realize sampling channel switching and negative voltage conversion. The CVM prototype shows that the voltage measurement range of the proposed system is larger than that of the superimposed bias voltage method, and the sampling accuracy of cell voltage is 3mV.

Based on the requirements of power processing unit(PPU), this paper proposes a converter suitable for its wide input and wide output voltage range applications. The first stage adopts a four-switch Buck-Boost converter, which operates in two-mode state and can meet the request of wide input and wide output voltage range. At the same time, the interleaved parallel technology is used to reduce the inductor volume, so that the power density can be increased. The circuit topology of the second stage employs an LLC resonant converter. The LLC resonant converter operates in fixed frequency mode to obtain a stable voltage transfer ratio, which is similar to the DC transformer; the LLC resonant converter can achieve zero voltage turn-on of the primary side switches and zero current turn-off of the secondary side diodes, which can contribute to the increase of efficiency.

It is known that the peak current in start-up process would affect the operation of the power supply system in Hall thrusters. Experimental testing shows that the peak current on the power supply side is elusive with different operating conditions. This causes the setting of over-current value of power supply into dilemma. The formation mechanism of the peak current on the power supply side is discussed and the theoretical boundary is deduced through the measurement of pressures in discharge channel, a given ionization rate and parameters of a Hall thruster. Results show that the analysis and predictions are in reasonable agreement with experimental results.

With the rapid development of hall electric propulsion, higher requirement for improving power and efficiency of power processing units was created. We introduce a kind of phase-shifted full-bridge soft switch technology, which is applied in anode-supply of hall electric propulsion. In the paper, the advantages of phase-shift full bridge converter in high voltage and high power anode-supply area are illustrated, as well as the working principle of this converter. This paper focuses on the problem of duty cycle loss and the condition of leading and lagging leg to achieve ZVS in the high power situation. Also the condition of the achievement for soft switch is verified by simulation analysis and the experiment results. Finally the demands of parameter selection for phase-shifted full-bridge converter in high power situation are presented.

A new photovoltaic MPPT system has been developed using an integrated transformerless Buck-Boost power converter to improve the efficiency. The paper describes the analysis, modeling and control of the Buck-boost power inverter. The transformerless Buck-boost power inverter includes a superboost converter and a buck converter though a variable mode controller to optimize the PV energy extraction. Finally, experiment research is proceeded to the MPPT system with battery chargers and DC load. Experiment results show that output power increases obviously under different solar radiation.

Silver nanowires with diameter around 100 nanometers were synthesized by a simple polyol method through the mediation of ferrum and tin species. The obtained Ag nanowires were uniform with diameter around 100nm and length up to 50μm. The formation mechanism of the Ag nanowires mediated by Fe and Sn ions was that the metal ions could prevent the oxide etching of seeds.

Fault identification aims to identify key variables most relevant to diagnose a specific fault. A new fault identification approach based on the partial F-value with the cumulative percent variation (CPV) is proposed. Although the partial F-value provides the better way to interpret the single discriminant function than the fault direction and the standardized fault direction, it still suffers from the irrelevant information and low computation efficiency. To improve its identification performance and reduce the computational complexity, the CPV based on each variable's maximum variation is proposed to determine candidate variables. These candidate variables are sufficient to express all change information of the abnormal behavior. Applying the proposed method to the Tennessee Eastman process (TEP), the results show more reliable fault identification than the fault direction, the standardized fault direction, and more efficient computation than the partial F -values.