Flexible temperature sensor with high sensitivity ranging from liquid nitrogen temperature to 1200℃

Flexible temperature sensors have been extensively investigated due to their prospect of wide application in various flexible electronic products.However,most of the current flexible temperature sensors only work well in a narrow temperature range,with their application at high or low temperatures still being a big challenge.This work proposes a flexible thermocouple temperature sensor based on aerogel blanket substrate,the temperature-sensitive layer of which uses the screen-printing technology to prepare indium oxide and indium tin oxide.It has good temperature sensitivity,with the test sensitivity reaching 226.7μV℃^(−1).Most importantly,it can work in a wide temperature range,from extremely low temperatures down to liquid nitrogen temperature to high temperatures up to 1200℃,which is difficult to be achieved by other existing flexible temperature sensors.This temperature sensor has huge application potential in biomedicine,aerospace and other fields.

AGO2a but not AGO2b mediates antiviral defense against infection of wild-type cucumber mosaic virus in tomato

Evolutionarily conserved antiviral RNA interference(RNAi)mediates a primary antiviral innate immunity preventing infection of broad-spectrum viruses in plants.However,the detailed mechanism in plants is still largely unknown,especially in important agricultural crops,including tomato.Varieties of pathogenic viruses evolve to possess viral suppressors of RNA silencing(VSRs)to suppress antiviral RNAi in the host.Due to the prevalence of VSRs,it is still unknown whether antiviral RNAi truly functions to prevent invasion by natural wild-type viruses in plants and animals.In this research,for the first time we applied CRISPR-Cas9 to generate ago2a,ago2b,or ago2ab mutants for two differentiated Solanum lycopersicum AGO2s,key effectors in antiviral RNAi.We found that AGO2a but not AGO2b was significantly induced to inhibit the propagation of not only VSR-deficient Cucumber mosaic virus(CMV)but also wild-type CMV-Fny in tomato;however,neither AGO2a nor AGO2b regulated disease induction after infection with either virus.Our findings firstly reveal a prominent role of AGO2a in antiviral RNAi innate immunity in tomato and demonstrate that antiviral RNAi evolves to defend against infection of natural wild-type CMV-Fny in tomato.However,AGO2a-mediated antiviral RNAi does not play major roles in promoting tolerance of tomato plants to CMV infection for maintaining health.

Design and fabrication of a full elastic sub-micron-Newton scale thrust measurement system for plasma micro thrusters

In this work,a force measurement system is proposed to measure the thrust of plasma microthruster with thrust magnitude ranging from sub-micro-Newtons to hundreds micro-Newtons.The thrust measurement system uses an elastic torsional pendulum structure with a capacitance sensor to measure the displacement,which can reflect the position change caused by the applied force perpendicular to the pendulum axis.In the open-loop mode,the steady-state thrust or the impulse of the plasma micro-thruster can be obtained from the swing of the pendulum,and in the closed-loop mode the steady-state thrust can be obtained from the feedback force that keeps the pendulum at a specific position.The thrust respond of the system was calibrated using an electrostatic weak force generation device.Experimental results show that the system can measure a thrust range from 0 to 200μN in both open-loop mode and closed-loop mode with a thrust resolution of 0.1μN,and the system can response to a pulse bit at the magnitude of 0.1 m N s generated by a micro cathode arc thruster.The background noise of the closed-loop mode is lower than that of the open-loop mode,both less than 0.1 m N/Hz in the range of 10 mHz to 5 Hz.

Effect of Sb composition on the band alignment of InAs/GaAsSb quantum dots

Aiming to achieve InAs quantum dots(QDs) with a long carrier lifetime,the effects of Sb component in cap layers on the band alignment of the InAs/GaAsSb QDs have been studied.InAs QDs with high density and uniformity have been grown by molecular beam epitaxy.With increasing Sb composition,the InAs/GaAsSb QDs exhibit a significant redshift and broadening photoluminescence(PL).With a high Sb component of 22%,the longest wavelength emission of the InAs/GaAs_(0.78)Sb_(0.22) QDs occurs at 1.5 μm at room temperature.The power-dependence PL measurements indicate that with a low Sb component of 14%,the InAs/GaAs_(0.86)Sb_(0.14) QDs have a type-Ⅰ and a type-Ⅱ carrier recombination processes,respectively.With a high Sb component of 22%,the InAs/GaAs_(0.78)Sb_(0.22) QDs have a pure type-Ⅱ band alignment,with three type-Ⅱ carrier recombination processes.Extracted from time-resolved PL decay traces,the carrier lifetime of the InAs/GaAs_(0.78)Sb_(0.22) QDs reaches 16.86 ns,which is much longer than that of the InAs/GaAs_(0.86)Sb_(0.14) QDs(2.07 ns).These results obtained here are meaningful to realize high conversion efficiency intermediate-band QD solar cells and other opto-electronic device.

A plasma equilibrium model for rapid estimation of SF-MPDT performance

In this work, a zero-dimensional plasma model for self-field magnetoplasmadynamic thrusters(SF-MPDTs) is proposed, which is based on the ion-number balance equation and energy balance equation, and can calculate the average electron temperature and the average ion temperature inside the discharge chamber conveniently. At the same time, the model can also predict the thruster performance, and the thruster performance predicted by the model is compared with experimental results, which proved the reliability of the model.

Silicon photonic transceivers for application in data centers

Global data traffic is growing rapidly,and the demand for optoelectronic transceivers applied in data centers(DCs)is also increasing correspondingly.In this review,we first briefly introduce the development of optoelectronics transceivers in DCs,as well as the advantages of silicon photonic chips fabricated by complementary metal oxide semiconductor process.We also summarize the research on the main components in silicon photonic transceivers.In particular,quantum dot lasers have shown great potential as light sources for silicon photonic integration—whether to adopt bonding method or monolithic integration—thanks to their unique advantages over the conventional quantum-well counterparts.Some of the solutions for highspeed optical interconnection in DCs are then discussed.Among them,wavelength division multiplexing and four-level pulseamplitude modulation have been widely studied and applied.At present,the application of coherent optical communication technology has moved from the backbone network,to the metro network,and then to DCs.

Inflation analyses of a circular elastomeric membrane with hydrostatic pressure

Composite diaphragm inflation （CDI） experiment is a useful methodology for exploring the mechanics relation of cell-cell junctions within a living epithelial sheet. In this paper, a new methodology of CDI experiment has been put forward. The finite deformation of a circular polydimezhylsiloxane elastomeric membrane, which is used as the substrate for the culture of epithelial cells, under hydrostatic pressure is explored by the theory of non-linear continuum mechanics. The simplified governing equations with minimum amount of differential equations and boundary conditions are obtained and solved by multiple shooting method. The influences on the membrane by hydrostatic pressure have been discussed.

Investigations of Thermal Deformation Based on the Monitoring System of Tianma 13.2 m VGOS Telescope

The thermal expansion of radio telescopes has been recognized as a significant systematic error in Very Long Baseline Interferometry(VLBI) data analysis. Although the thermal expansion model recommended by International Earth Rotation Service(IERS) Conventions 2010 can achieve millimeter accuracy for the International VLBI Service for Geodesy and Astrometry(IVS) routine telescopes, both the International Terrestrial Reference Frame 2020(ITRF2020) in preparation and the VLBI2010 project encourage the scientific community to reconsider its modeling. To this end, we developed a monitoring system for the Tianma 13.2 m VLBI Global Observing System(VGOS) telescope. Based on the observed data, we refined the IERS expansion model, with results showing that the accuracy of our modified model was improved by 1.9 times. It suggested that the IERS thermal expansion model can achieve the declared millimeter accuracy, and refining its modeling can meet the requirement of 0.3 mm rms stability of the VGOS antenna reference point for the VLBI2010 project.

A 16-parameter GEO Broadcast Ephemeris

Currently,the broadcast ephemerides used in GEOs are same as those of the MEOs and IGSOs in the BeiDou navigation constellation.However,a trade-off strategy,i.e.an orbital inclination of 5°rotation,is needed in the fitting algorithm to solve the ephemeris parameters as well as the user satellite position computation for GEOs.Based on the standard broadcast ephemerides,the representations of both the orbit and its perturbation were revised according to the second class of nonsingular orbital elements.In this research,a 16-parameter broadcast ephemeris is presented specifically for GEOs,and user satellite position computation formulas were derived correspondingly.Fit simulations show that the root of mean squares(RMS)of user range error(URE)with two hour and three hour data sets are better than 0.05 m and 0.1 m,respectively.

A large-area bionic skin for high-temperature energy harvesting applications

For the large amount of waste heat wasted in daily life and industrial production,we propose a new type of flexible thermoelectric generators(F-TEGs)which can be used as a large area bionic skin to achieve energy harvesting of thermal energy.With reference to biological structures such as pinecone,succulent,and feathers,we have designed and fabricated a biomimetic flexible TEG that can be applied in a wide temperature range which has the highest temperature energy harvesting capability currently.The laminated free structure of the bionic F-TEG dramatically increases the efficiency and density of energy harvesting.The F-TEGs(single TEG only 101.2 mg in weight),without an additional heat sink,demonstrates the highest output voltage density of 286.1 mV/cm^(2)and the maximum power density is 66.5 mW/m^(2) at a temperature difference of nearly 1000℃.The flexible characteristics of F-TEGs make it possible to collect the diffused thermal energy by flexible attachment to the outer walls of high-temperature pipes and vessels of different diameters and shapes.This work shows a new design and application concept for flexible thermal energy collectors,which fills the gap of flexible energy harvesting in high-temperature environment.

Highly sensitive flexible heat flux sensor based on a microhole array for ultralow to high temperatures

With the growing demand for thermal management of electronic devices,cooling of high-precision instruments,and biological cryopreservation,heat flux measurement of complex surfaces and at ultralow temperatures has become highly imperative.However,current heat flux sensors(HFSs)are commonly used in high-temperature scenarios and have problems when applied in low-temperature conditions,such as low sensitivity and embrittlement.In this study,we developed a flexible and highly sensitive HFS that can operate at ultralow to high temperatures,ranging from−196°C to 273°C.The sensitivities of HFSs with thicknesses of 0.2 mm and 0.3 mm,which are efficiently manufactured by the screen-printing method,reach 11.21μV/(W/m2)and 13.43μV/(W/m2),respectively.The experimental results show that there is a less than 3%resistance change from bending to stretching.Additionally,the HFS can measure heat flux in both exothermic and absorptive cases and can measure heat flux up to 25 kW/m2.Additionally,we demonstrate the application of the HFS to the measurement of minuscule heat flux,such as heat dissipation of human skin and cold water.This technology is expected to be used in heat flux measurements at ultralow temperatures or on complex surfaces,which has great importance in the superconductor and cryobiology field.

Purification and Characterization of a New Ribosome Inactivating Protein from Cinchonaglycoside C-treated Tobacco Leaves

A new ribosome-inactivating protein （RIP） with a molecular weight of 31 kDa induced by Cinchonaglycoside C （1） designated CIP31, was isolated from tobacco leaves. Analysis of this protein sequence indicated that it belongs to the RIP family and it was distinct from the other plant RIPs reported previously at its N-terminal amino acid sequence. CIP31 can directly impair synthesis of coat protein （CP） of tobacco mosaic virus （TMV）, which resulted in inhibition of TMV long distance movement and multiplication in tobacco plants at concentrations of ng/mL. Furthermore, no toxicity was shown to the growth and fertility of the plants. CIP31 was synthesized only in the presence of Cinchonaglycoside C （1） and was independent of the salicylic acid （SA） signal pathway. We provided evidence for the SA-independent biological induction of resistance.

25 Gb/s directly modulated ground-state operation of 1.3 μm InAs/GaAs quantum dot lasers up to 75℃

We report 25 Gb/s high-speed directly modulated ground-state operation of 1.3 μm In As/Ga As quantum dot(QD) lasers grown by molecular beam epitaxy. The active region of the lasers consists of eight layers of p-doped In As QDs with high uniformity and density. Ridge-waveguide lasers with a 3-μm-wide and 300-μm-long cavity show a low threshold current of 14.4 m A at 20°C and high temperature stability with a high characteristic temperature of 1208 K between 20°C and 70°C. Dynamic response measurements demonstrate that the laser has a 3 d B bandwidth of 7.7 GHz at 20°C and clearly opened eye diagrams even at high temperatures up to 75°C under a 25 Gb/s direct modulation rate.

A thin-film temperature sensor based on a flexible electrode and substrate

Accurate temperature measurements can efficiently solve numerous critical problems and provide key information.Herein,a flexible micro-three-dimensional sensor,with a combination of platinum and indium oxide to form thermocouples,is designed and fabricated by a microfabrication process to achieve in situ real-time temperature measurements.The stability and reliability of the sensor are greatly improved by optimizing the process parameters,structural design,and preparation methods.A novel micro-three-dimensional structure with better malleability is designed,which also takes advantage of the fast response of a two-dimensional thin film.The as-obtained flexible temperature sensor with excellent stability and reliability is expected to greatly contribute to the development of essential components in various emerging research fields,including bio-robot and healthcare systems.The model of the application sensor in a mask is further proposed and designed to realize the collection of health information,reducing the number of deaths caused by the lack of timely detection and treatment of patients.