Flexible Grid Graphene Electrothermal Films for Real-Time Monitoring Applications.

Flexible electrothermal films are crucial for protecting equipment and systems in cold weather, such as ice blockages in natural gas pipelines and icing on aircraft wings. Therefore, a flexible electric heater is one of the essential devices in industrial operations. One of the main challenges is to develop flexible electrothermal films with low operating voltage, high steady-state temperature, and good mechanical stability. In this study, a flexible electrothermal film based on graphene-patterned structures was manufactured by combining the laser induction method and the transfer printing process. The grid structure design provides accurate real-time monitoring for the application of electrothermal films and shows potential in solving problems related to deicing and clearing ice blockages in pipelines. The flexible electrothermal film can reach a high heating temperature of 165 °C at 15 V and exhibits sufficient heating stability. By employing a simple and efficient method to create a flexible, high-performance electrothermal film, we provide a reliable solution for deicing and monitoring applications.

3D Printing of Individualized Microfluidic Chips with DLP-Based Printer.

Microfluidic chips have shown their potential for applications in fields such as chemistry and biology, and 3D printing is increasingly utilized as the fabrication method for microfluidic chips. To address key issues such as the long printing time for conventional 3D printing of a single chip and the demand for rapid response in individualized microfluidic chip customization, we have optimized the use of DLP (digital light processing) technology, which offers faster printing speeds due to its surface exposure method. In this study, we specifically focused on developing a fast-manufacturing process for directly printing microfluidic chips, addressing the high cost of traditional microfabrication processes and the lengthy production times associated with other 3D printing methods for microfluidic chips. Based on the designed three-dimensional chip model, we utilized a DLP-based printer to directly print two-dimensional and three-dimensional microfluidic chips with photosensitive resin. To overcome the challenge of clogging in printing microchannels, we proposed a printing method that combined an open-channel design with transparent adhesive tape sealing. This method enables the rapid printing of microfluidic chips with complex and intricate microstructures. This research provides a crucial foundation for the development of microfluidic chips in biomedical research.

Three dimensional high-performance micro-supercapacitors with switchable high power density and high energy density.

In the field of microscale energy storage, the fabrication of micro-supercapacitors (MSCs) with high power density and high energy density has always been a focus of research. In this work, laser-induced porous graphene and chemically deposited manganese dioxide nanoparticles are used as electrode materials, and a switchable MSC with two energy storage principles is obtained by designing symmetric interdigitated and square electrode structures. The aim is to overcome the preparation challenge of supercapacitors with high energy density and high power density by switching between two modes. In this MSC, the energy density of the high energy density mode (5.89 µW h cm-2) is 3.36 times that of the high power density mode (1.75 µW h cm-2), while the power density of the high power density mode (43.06 µW cm-2) is 1.44 times that of the high energy density mode (29.96 µW cm-2). In addition, under the drive of five serially connected MSCs, 27 LED lights can be continuously lit for 5 minutes. Therefore, this work provides a facile and novel method for the development of MSCs with high power density and high energy density, suggesting a great practical application value in the development of MSCs.

A flexible metal nano-mesh strain sensor with the characteristic of spontaneous functional recovery after fracture damage.

Developing flexible sensors with high sensitivity, a wide sensing range, and good stability is a challenge. By replicating the anodic aluminum oxide (AAO) hole structure, we proposed new strain sensors with Pt nano-mesh films embedded in polydimethylsiloxane (PDMS) films. The nano-mesh strain sensor exhibited high sensitivity (a gauge factor of 4500) and a sensing range as high as 90%. The resistance remained almost completely unchanged after 1500 loading/unloading cycles of 15% strain, demonstrating the high repeatability and stability of the sensor. In addition, even if the nano-mesh experienced an open circuit by overstraining, the sensor can still measure strain within 45% after recovery. The capability of spontaneous functional recovery after fractural damage considerably extends its service life. Finally, the nano-mesh strain sensors were worn on the wrist and neck to monitor wrist movement and throat vibration, respectively. Signals corresponding to swallowing, throat clearing, and letter pronunciation were clearly distinguished from the peak value and signal patterns. These results indicate that the metal nano-mesh strain sensors have great potential for applications in wearable devices, electronic skin, and flexible robotics.

Compound-Specific Chlorine Isotope Analysis of Organochlorine Pesticides by Gas Chromatography-Negative Chemical Ionization Mass Spectrometry.

Compound-specific stable chlorine isotope analysis (CSIA-Cl) is an important method for identifying sources of organochlorine contaminants and helping assess their quantification of transformation processes. However, the present CSIA-Cl is challenged by either redundant conversion pretreatment or complicated mathematical correction. To overcome the mentioned problems, a novel method has been developed for the CSIA-Cl of eight organochlorine pesticides using gas chromatography-negative chemical ionization mass spectrometry (GC-NCI-qMS) in this study. The instrument parameters, acquisition mode, and required injection amounts were optimized in terms of the precision of GC-NCI-qMS. An ionization energy of 90 eV and emission current of 90 µA were selected, and the precisions for eight organochlorine pesticides were in the range of 0.37‰-2.15‰ in single ion monitoring (SIM) mode when the injected amount was 0.50 mg L-1 (viz. 0.5 ng on column). Furthermore, when standards from Supelco and O2si were calibrated using standards from AccuStandard regarded as external isotope standard, chlorine isotope composition of α-hexachlorocyclohexane (α-HCH) and 2, 2-dichloro-1, 1-bis (4-chlorophenyl) ethylene (p, p'-DDE) in Supelco and O2si was confidently differentiated. The provenance identification method was validated by three organochlorine contaminated groundwater samples and showed a prospect in identifying the source of organochlorine pesticides.

Numerical Simulations and the Design of Magnetic Field-Enhanced Electron Impact Ion Source with Hollow Cylinder Structure.

An electron impact ion source-adopted magnetic field-enhanced technology has been designed for enhancing the electron intensity and the ionization efficiency. Based on the ion optic focus mechanism, an electron impact ionization source was designed, and the electron entrance into the ionization chamber was designed with a hollow cylinder structure to improve the ion extraction efficiency. Numerical simulation and optimal geometry were optimized by SIMION 8.0 to provide higher electron intensity and ion transmission efficiency. To improve the electron intensity, the influence of the filament potential and magnetic intensity was investigated, and the values of 70 eV and 150 Gs were chosen in our apparatus. Based on the optimal parameters, the air in the lab and oxygen gas was detected by the homemade apparatus, and the ion intensity was detected in the positive and negative ion modes, respectively. The homemade electron impact ion source apparatus has the potential to enhance ionization efficiency applied in the mass spectrometer ionization source.