Low-Temperature Wearable Strain Sensor Based on a Silver Nanowires/Graphene Composite with a Near-Zero Temperature Coefficient of Resistance.

Currently, the exploration of wearable strain sensors that can work under subzero temperatures while simultaneously possessing anti-interference capability toward temperature is still a grand challenge. Herein, we present a low-temperature wearable strain sensor that is constructed via the incorporation of a Ag nanowires/graphene (Ag NWs/G) composite into the polydimethylsiloxane (PDMS) polymer. The Ag NWs/G/PDMS strain sensor exhibits promising flexibility at a very low temperature (-40 °C), outstanding fatigue resistance with low hysteresis energy, and near-zero temperature coefficient of resistance (TCR). The Ag NWs/G/PDMS strain sensor shows excellent sensing performance under subzero temperatures with a very high gauge factor of 9156 under a strain of >36%, accompanied by a noninterference characteristic to temperature (-40 to 20 °C). The Ag NWs/G/PDMS strain sensor also demonstrates the feasibility of monitoring various human movements such as finger bending, arm waving, wrist rotation, and knee bending under both room temperature and low-temperature conditions. This work initiates a new promising strategy to construct next-generation wearable strain sensors that can work stably and effectively under very low temperatures.

An extremely sensitive aptasensor based on interfacial energy transfer between QDS SAMs and GO.

In this work we designed a fluorescent self-assemblied multilayers, with thrombin aptamers and ssDNA as aptamer fixed onto the outermost layer, respectively. This multilayers can effectively sense biomolecules by interfacial florescence resonance energy transfer from multilayers to graphene oxide. High fluorescence quenching efficiency of graphene oxide and self-assemblied membrane' concentration results in good sensitivity for biosensing. A new interfacial sensing method with extremely high sensitivity for thrombin and DNA sequence was established, and the detection limit for thrombin and DNA was 16.2pM and 72.6 fM, respectively.

Visual and trap emission spectrometric detections of Ag (I) ion with mesoporous ZnO/CdS@SiO2 core/shell nanocomposites.

A new method for the preparation of mesoporous ZnO/CdS@SiO(2) core/shell nanostructure (CSN) has been developed. The mesoporous silica shells allow Ag(+) to enter into the interior of the nanostructures to contact with ZnO/CdS core, accordingly causes the quenching of its band edge emission (475 nm) along with a simultaneous enhancement of red emission at around 595 nm. So, a novel visual fluorescence detection strategy for Ag(+) ion is proposed based on a common core/shell Quantum dots nanostructure. Under optimal conditions, the enhanced fluorescence intensity at 595 nm increased linearly with the concentration of Ag(+) ion ranging from 0.03 µM to 0.24 µM with a detection limit (3σ) of 3.3 nM.

[Determination of the daily changes curve of nitrogen oxides in the atmosphere by digital imaging colorimetry method].

From the digital images of the red complex which resulted in the interaction of nitrite with N-(1-naphthyl) ethylenediamine dihydrochloride and P-Aminobenzene sulfonic acid, it could be seen that the solution colors obviously increased with increasing the concentration of nitrite ion. The JPEG format of the digital images was transformed into gray-scale format by origin 7.0 software, and the gray values were measured with scion image software. It could be seen that the gray values of the digital image obviously increased with increasing the concentration of nitrite ion, too. Thus a novel digital imaging colorimetric (DIC) method to determine nitrogen oxides (NO(x)) contents in air was developed. Based on the red, green and blue (RGB) tricolor theory, the principle of the digital imaging colorimetric method and the influential factors on digital imaging were discussed. The present method was successfully applied to the determination of the daily changes curve of nitrogen oxides in the atmosphere and NO2- in synthetic samples with the recovery of 97.3%-104.0%, and the relative standard deviation (RSD) was less than 5.0%. The results of the determination were consistent with those obtained by spectrophotometric method.