Ultrasensitive Detection of Vitamin E by Signal Conversion Combined with Core-satellite Structure-based Plasmon Coupling Effect

Rapidly and sensitively surface-enhanced Raman scattering (SERS) detection of molecular biomarkers from real samples is still a challenge, because the intrinsically trace analytes may have a low molecular affinity for...

Acceleration Anomaly Detection Method for Sensor Axle Box of Unmanned Vehicle

Detecting the anomaly acceleration of the sensor’s axle box of unmanned vehicles is very important for judging the wear condition of vehicle track and evaluating the state of the track. A capacitive accelerometer is connected with acquisition equipment to collect the information of train axle box’s acceleration change when the vehicle is running; instrument amplifier AD8250 with a digitally programmable gain is selected as system signal conversion chip to realize acceleration signal conversion; sliding variance of axle box’s acceleration of the unmanned vehicle is calculated based on sliding variance statistical analysis method, which is confirmed by time window and distance window. Fixing the width of a sliding window according to the response statistics caused by the line excitation link, the acceleration sliding variance is compared with the standard one to determine whether the acceleration is in an anomaly state. The test results show that the anomaly acceleration of the sensor axle box of the unmanned vehicle detected by the proposed method is consistent with the actual results, which provides a reliable basis for vehicle track condition assessment.

Er-Doped Tapered Fiber Amplifier for High Peak Power Sub-ns Pulse Amplification

A tapered Er-doped fiber amplifier for high peak power pulses amplification has been developed and tested. The core diameter changed from 15.8 µm (mode field diameter (MFD) 14.5 µm) to 93 µm (MFD 40 µm) along 3.7 m maintaining single-mode performance at 1555 nm (according to the S2-method, the part of the power of high-order modes does not exceed 1.5%). The amplification of 0.9 ns pulses with spectral width below 0.04 nm up to a peak power above 200 kW (limited by self-phase modulation) with a slope pump-to-signal conversion efficiency of 15.6% was demonstrated.

Discrete-to-analog signal conversion in human pluripotent stem cells

During development, state transitions are coordinated through changes in the identity of molecular regulators in a cell state- and dose specific manner. The ability to rationally engineer such functions in human pluripotent stem cells (hPSC) will enable numerous applications in regenerative medicine. Herein we report the generation of synthetic gene circuits that can detect a discrete cell state, and upon state detection, produce fine-tuned effector proteins in a programmable manner. Effectively, these gene circuits convert a discrete (digital-like) cell state into an analog signal by merging AND-like logic integration of endogenous miRNAs (classifiers) with a miRNA-mediated output fine-tuning technology (miSFITs). Using an automated miRNA identification and model-guided circuit optimization approach, we were able to produce robust cell state specific and graded output production in undifferentiated hPSC. We further finely controlled the levels of endogenous BMP4 secretion, which allowed us to document the effect of endogenous factor secretion in comparison to exogenous factor addition on early tissue development using the hPSC-derived gastruloid system. Our work provides the first demonstration of a discrete-to-analog signal conversion circuit operating in living hPSC, and a platform for customized cell state-specific control of desired physiological factors, laying the foundation for programming cell compositions in hPSC-derived tissues and beyond.

Wireless Passive High-Temperature Sensor Readout System for Rotational-Speed Measurement

Rotational-speed measurement in harsh environments is an important topic. However, the high rotation results in rapid frequency variations in the signals of a sensor and changes in physical properties under extreme thermal circumstances cause significant difficulties in reading signals. To address this problem, we adopt wireless passive measurement methods to design a special characteristic signal circuit module that achieves precise measurement of rotational speed at high temperatures. The sensor and the readout system include a variable frequency source, a readout antenna, and a radio frequency demodulation circuit. Herein, a demodulation detector of the signal conversion circuit is designed and used in the envelope detection module of the single sideband demodulation method. In addition, a conversion circuit test platform for high-temperature environment sensor signal is developed. From the testing, the output signal demodulation of the sensor was observed under a maximum temperature of 700°C with error less than 0.12%. The new sensor and measurement method do not require physical leads and achieve wireless noncontact accurate measurement of rotational speed at high temperature.

Unjuk Kerja GPIO, PWM, ADC dan Timer pada Mikrokontroler STM32F103, ESP32S dan ATMega328

Perangkat embedded system pada masa sekarang memiliki banyak pilihan terhadap jenis mikrokontroler yang sesuai dengan kebutuhan. Hal ini menjadi tantangan tersendiri bagi pengguna ketika diharuskan untuk memilih salah satu jenis mikrokontroler tersebut. Sebagai contoh permasalahan apakah mikrokontroler yang telah dipilih tersebut memiliki sejumlah pin GPIO yang diinginkan, dengan frekuensi switching yang tinggi, berapakah jumlah kanal, resolusi, linieritas dan durasi konversi ADC, bagaimana kemampuan peripheral internal DAC, Timer dan PWM yang bisa dibangkitkan dari mikrokontroler tersebut. Penelitian ini telah membandingkan setidaknya 4 peripheral internal utama yang dimiliki oleh 3 jenis mikrokontroler. Metode yang dilakukan adalah dengan menguji karakteristik GPIO, PWM, TIMER dan ADC pada 3 jenis mikrokontroler yaitu Arduino ATMega328, STM32F103C8 dan ESP32. Eksperiment dilakukan dengan mengevaluasi frekuensi switching digital ouput, mengevaluasi resolusi sinyal hasil konversi ADC, mengevaluasi ketepatan hasil instruksi delay berkaitan dengan timer program dan waktu konversi sinyal DAC semuanya dilakukan pada masing-masing mikrokontroler. Hasil akhir dari penelitian ini menunjukkan, mikrokontroler ESP32 memiliki unjuk kerja GPIO, PWM, TIMER dan ADC terbaik apabila dibandingkan dengan jenis lainnya. Penelitian ini juga membuktikan integrasi FreeRTOS pada Framework Arduino bisa berfungsi dengan optimal meskipun mikrokontroler berjalan pada 2 task yang berbeda di 2 core CPU yang bekerja secara pararel. Frekuensi switching digital output pada ESP32 mampu mencapai 3MHz, waktu konversi ADC hanya 5,7us dan DAC hanya 3,7us. Today's embedded systems have many choices for the type of microcontroller that suits the needs. This is a challenge in itself for users when required to choose one type of microcontroller. For example, the problem of whether the selected microcontroller has the desired number of GPIO pins, with a high switching frequency, what is the number of channels, resolution, linearity, and duration of the ADC conversion, what is the ability of the internal DAC, Timer and PWM peripherals that can be generated from the microcontroller. This study has compared at least 4 main internal peripherals owned by 3 types of microcontrollers. The method used is to test the characteristics of the GPIO, PWM, TIMER, and ADC on 3 types of microcontrollers, namely Arduino ATMega328, STM32F103C8, and ESP32. The experiment was carried out by evaluating the digital output switching frequency, evaluating the signal resolution of the ADC conversion result, evaluating the accuracy of the delay instruction results related to the program timer and DAC signal conversion time, all of which were carried out on each microcontroller. The final results of this study indicate that the ESP32 microcontroller has the best GPIO, PWM, TIMER, and ADC performance when compared to other types. This research also proves that the FreeRTOS integration on the Arduino Framework can function optimally even though the microcontroller runs on 2 different tasks on 2 CPU cores that work in parallel. The digital output switching frequency on the ESP32 is capable of reaching 3MHz, the ADC conversion time is only 5.7us and the DAC is the only 3.7us.

Plant Gravitropism and Signal Conversion under a Stress Environment of Altered Gravity

Humans have been committed to space exploration and to find the next planet suitable for human survival. The construction of an ecosystem that adapts to the long-term survival of human beings in space stations or other planets would be the first step. The space plant cultivation system is the key component of an ecosystem, which will produce food, fiber, edible oil and oxygen for future space inhabitants. Many plant experiments have been carried out under a stimulated or real environment of altered gravity, including at microgravity (0 g), Moon gravity (0.17 g) and Mars gravity (0.38 g). How plants sense gravity and change under stress environment of altered gravity were summarized in this review. However, many challenges remain regarding human missions to the Moon or Mars. Our group conducted the first plant experiment under real Moon gravity (0.17 g) in 2019. One of the cotton seeds successfully germinated and produced a green seedling, which represents the first green leaf produced by mankind on the Moon.

Copper Oxide Nanoparticle-Based Immunosensor for Zearalenone Analysis by Combining Automated Sample Pre-Processing and High-Throughput Terminal Detection

A rapid and high-throughput fluorescence detection method for zearalenone (ZEN) based on a CuO nanoparticle (NP)-assisted signal amplification immunosensor was developed using an automated sample pretreatment and signal conversion system. CuO NPs with high stability and biocompatibility were used as carriers to immobilize anti-ZEN antibodies. The obtained CuO NP-anti-ZEN can maintain the ability to recognize target toxins and act as both a signal source and carrier to achieve signal conversion using automated equipment. In this process, target toxin detection is indirectly transformed to Cu2+ detection because of the large number of Cu2+ ions released from CuO NPs under acidic conditions. Finally, a simple and high-throughput fluorescence assay based on a fluorescent tripeptide molecule was employed to detect Cu2+, using a multifunctional microporous plate detector. A good linear relationship was observed between the fluorescence signal and the logarithm of ZEN concentration in the range of 16.0–1600.0 μg/kg. Additionally, excellent accuracy with a high recovery yield of 99.2–104.9% was obtained, which was concordant with the results obtained from LC-MS/MS of naturally contaminated samples. The CuO NP-based assay is a powerful and efficient screening tool for ZEN detection and can easily be modified to detect other mycotoxins.

Study on Modulation Strategy of Electronic Converters Based on Improved D-NPC Topology for Full Electric Vehicle

The battery is the only power source of full electric vehicles, and the converter plays a key role in power and signal conversion; therefore, the stability and reliability of the converter determine the performance of the whole vehicle system. In order to improve the overall performance of the converter and optimize the function of the ID-NPC (improved diode neutral-point-clamped) topology with power allocation, the two-level topology is improved, and it is also a part of the ID-NPC topology. Based on the ID-NPC topology, the converter level can switch according to the proposed three-level and two-level modulation conversion strategies, which extends the fault-tolerant function of the converter. Finally, a simulation and experimental platform is built to verify the function of the improved topology and the feasibility of the proposed modulation strategy.