Synthesis of photoactivated highly fluorescent Mn2+-doped ZnSe quantum dots as effective lead sensor in drinking water

In this article, an impedance debris sensor capable of simultaneously detecting inductance and resistance parameters is presented, which mainly consists of two planar coils in parallel, two excitation silicon steel strips inserted in the inner hole of coils and a built-in silicon steel strip located in the center of channel. The excitation silicon steel strips and the built-in silicon steel strip establish a detection region with a high-gradient magnetic field to improve the sensitivity of the sensor. And the square channel makes full use of the sensitive detection region, thereby further increasing the detection throughput. Experiments have shown that the amplitudes of the inductance and resistance pulses generated by the same particle many times through the detection region are different. The uncertainty of the sensor can be reduced for accurate size information by combining the detection results of the inductance and resistance parameters. By comparing and analyzing the inductance parameter detection result and the resistance parameter detection result, the impedance debris sensor can distinguish and measure 25  μ m iron particle and 85  μ m copper particle. With its high sensitivity, high throughput, and capability of multiparameter detection, this sensor can potentially be used for health monitoring of hydraulic equipment.

An Impedance Debris Sensor Based on a High-Gradient Magnetic Field for High Sensitivity and High Throughput

Foodborne diseases caused by pathogenic bacteria pose a serious threat to human health. Early and rapid detection of foodborne pathogens is an urgent task for preventing disease outbreaks. Microfluidic devices are simple, automatic, and portable miniaturized systems. Compared with traditional techniques, microfluidic devices have attracted much attention because of their high efficiency and convenience in the concentration and detection of foodborne pathogens. This article firstly reviews the bio-recognition elements integrated on microfluidic chips in recent years and the progress of microfluidic chip development for pathogen pretreatment. Furthermore, the research progress of microfluidic technology based on optical and electrochemical sensors for the detection of foodborne pathogenic bacteria is summarized and discussed. Finally, the future prospects for the application and challenges of microfluidic chips based on biosensors are presented. 

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Recent advancements in microfluidic chip biosensor detection of foodborne pathogenic bacteria: a review

This work combines the high-temperature sintering method and atomic layer deposition (ALD) technique, and yields SiO2 /AlOx -sealed γ-CsPbI3 nanocrystals (NCs). The black-phase CsPbI3 NCs, scattered and encapsulated firmly in solid SiO2 sub-micron particles, maintain in black phases against water soaking, ultraviolet irradiation, and heating, exhibiting remarkable phase stability. A new phase-transition route, from γ via β to α phase without transferring into δ phase, has been discovered upon temperature increasing. The phase stability is ascribed to the high pressure exerted by the rigid SiO2 encapsulations, and its condensed amorphous structures that prevent the permeation of H2 O molecules. Nanoscale coating of Al2 O3 thin films, which are deposited on the surface of the CsPbI3 -SiO2 by ALD, enhances the protection against O2 infiltration, greatly elevating the high-temperature stability of CsPbI3 NCs sealed inside, as the samples remain bright after 1-h annealing in air at 400 °C. These fabrication and encapsulation techniques effectively prevent the formation of δ-CsPbI3 under harsh environment, bringing the high-pressure preservation of black-phase CsPbI3 from laboratory to industry toward potential applications in both photovoltaic and fluorescent areas.

Remarkable Black-Phase Robustness of CsPbI3 Nanocrystals Sealed in Solid SiO2 /AlOx Sub-Micron Particles.

The inductive detection of wear debris in lubrication oil is an effective method to monitor the machine status. As the wear debris is usually micro scale, a micro inductive sensor is always used to detect them in research papers or high-tech products. However, the improvement of detection sensitivity for micro inductive sensors is still a great challenge, especially for early wear debris of 20 μm or smaller diameter. This paper proposes a novel method to improve the detection sensitivity of a micro inductive sensor. Regarding the magnetic powder surrounding the sensor, the magnetic field in the core of the sensor where the wear debris pass through would be enhanced due to the increased relative permeability. Thus, the inductive signal would be improved and the detection sensitivity would be increased. It is found that the inductive signal would linearly increase with increasing the concentration of the magnetic powder and this enhancement would also be effective for wear debris of different sizes. In addition, the detection limit of the micro inductive sensor used in our experiment could be extended to 11 μm wear debris by the proposed method.

https://www.mdpi.com/2072-666X/10/7/440/pdf

Improving Sensitivity of a Micro Inductive Sensor for Wear Debris Detection with Magnetic Powder Surrounded

Fluorescence-enhanced microfluidic sensor for highly sensitive in-situ detection of copper ions in lubricating oil

Inductive wear debris sensor has been widely used in real time machine lubricant oil condition monitoring and fault forecasting. However, the small sensing zone, which is designed for high sensitivity, of the existing sensors leads to low throughput. In order to improve the throughput, a novel multichannel wear debris sensor that is based on phase division multiplexing is presented. By introducing the phase shift circuit into the system, multiple sensing coils could work at different initial phases. Multiple signals of sensing coils could be combined into one output without information loss. Synchronized sampling is used for data recording, and output signals of multiple sensing coils are extracted from the recorded data. A four-channel wear debris sensor system was designed to demonstrate our method. Subsequently, crosstalk analysis, pseudo-dynamic testing and dynamic testing were conducted to check the sensing system. Results show that signals of four sensing coils could be simultaneously detected and the detection limit for ferrous wear debris is 33 μm. Using the presented method, real time wear debris detection in multiple channels could be achieved without increasing the number of excitation source and data acquisition equipment.

https://www.mdpi.com/2072-666X/10/4/246/pdf

Multichannel Inductive Sensor Based on Phase Division Multiplexing for Wear Debris Detection.

Fluorescence enhanced microfluidic sensor with CsPbI3 probe for lubricant copper ions on-site rapid detection based on SiO2 inverse opal photonic crystals

It is urgent that a convenient and sensitive technique of detecting Hg2+ be developed because of its toxicity. Conventional fluorescence analysis works with a single fluorescence probe, and it often suffers from signal fluctuations which are influenced by external factors. In this research, a novel dual-emission probe assembled through utilizing CdTe quantum dots (QDs) and rhodamine B was designed to detect Hg2+ visually. Only the emission of CdTe QDs was quenched after adding Hg2+ in the dual-emission probe, which caused an intensity ratio change of the two different emission wavelengths and hence facilitated the visual detection of Hg2+. Compared to single emission QDs-based probe, a better linear relationship was shown between the variation of fluorescence intensity and the concentration of Hg2+, and the limit of detection (LOD) was found to be11.4 nM in the range of 0–2.6 μM. Interestingly, the intensity of the probe containing Hg2+ could be recovered in presence of glutathione (GSH) due to the stronger binding affinity of Hg2+ towards GSH than that towards CdTe QDs. Based on this phenomenon, an IMPLICATION logic gate using Hg2+/GSH as inputs and the fluorescence signal of QDs as an output was constructed.

https://www.mdpi.com/2072-666X/12/6/713/pdf

Dual-Emission Fluorescence Probe Based on CdTe Quantum Dots and Rhodamine B for Visual Detection of Mercury and Its Logic Gate Behavior

The utility model relates to the technical field of lubricating oil analysis and detection, in particular to a separation device and a separation system for abrasive particles in lubricating oil basedon surface acoustic waves. According to the utility model, the advantages of high energy density, easiness in integration and the like of surface acoustic waves are fully utilized, and the surface acoustic waves are combined with a microfluidic channel with a specific geometrical shape processed by a soft lithography technology, so that online continuous separation of the abrasive particles in the lubricating oil is realized, and a foundation is laid for accurate detection of the abrasive particles. According to the separation device and the separation system, structures such as a physical filter screen are omitted, filth blockage is avoided, the integration degree of the device and the separation system is high, and the online separation effect is good.

Gao Yuefeng

Papers

Fluorescence-enhanced microfluidic sensor for highly sensitive in-situ detection of copper ions in lubricating oil

Multichannel Inductive Sensor Based on Phase Division Multiplexing for Wear Debris Detection.

Fluorescence enhanced microfluidic sensor with CsPbI3 probe for lubricant copper ions on-site rapid detection based on SiO2 inverse opal photonic crystals

Dual-Emission Fluorescence Probe Based on CdTe Quantum Dots and Rhodamine B for Visual Detection of Mercury and Its Logic Gate Behavior

Device and method for separating abrasive particles in lubricating oil based on surface acoustic waves