Explore the vast range of titles available.

In the present study, the analytical strengths and limitations of near-infrared (NIR) spectroscopy to non-invasively characterize organic components in painting materials have been investigated. In spite of the increased amount of information available today from advanced modern analytical instrumentations dedicated to cultural heritage, the non-invasive identification of materials belonging to the wide class of organic compounds historically used in paintings is still a challenging task. Near-infrared spectroscopy offers several attractive features that make this technique particularly suitable to this purpose. In fact, it is non-invasive, allows for non-contact measurements in reflectance mode, gives molecular information on complex macromolecules, and can be performed on-site by means of portable devices. First-derivative transformation of reflectance spectroscopic data has been applied to provide a simple and fast way to deduce more information from NIR spectra. This approach has allowed spectral features to be identified that can be useful to distinguish different compounds belonging to the classes of lipids, proteins, and resins. To this purpose, at first, a spectral database of pure standard has been collected. Our analytical approach was then successfully validated on pictorial models reproducing the typical stratigraphy of an easel painting. As final step, the study of a real painting has been attempted and a drying oil, animal glue, and a terpenic natural resin, as well as an earth pigment were clearly identified, as cross-validated by GC-MS analysis.

Walking and running have fundamentally different biomechanics, which makes developing devices that assist both gaits challenging. We show that a portable exosuit that assists hip extension can reduce the metabolic rate of treadmill walking at 1.5 meters per second by 9.3% and that of running at 2.5 meters per second by 4.0% compared with locomotion without the exosuit. These reduction magnitudes are comparable to the effects of taking off 7.4 and 5.7 kilograms during walking and running, respectively, and are in a range that has shown meaningful athletic performance changes. The exosuit automatically switches between actuation profiles for both gaits, on the basis of estimated potential energy fluctuations of the wearer’s center of mass. Single-participant experiments show that it is possible to reduce metabolic rates of different running speeds and uphill walking, further demonstrating the exosuit’s versatility.

[...]we have worked hard to increase the size and diversity of our Editorial Board, which now includes many more members from beyond the staff of NYBG, representing institutions from elsewhere in the United States and from a range of other countries. [...]we are planning to develop a new, semi-regular feature that will be called The Botanist’s Toolkit. Examples include notes explaining new software, techniques for collecting particular groups of plants, construction of field tools and equipment (such as portable specimen dryers or telescopic pole pruners, or creative use of drones), photography tips, etc.

In the new era of modern flexible and bendable technology, graphene-based materials have attracted great attention. The excellent electrical, mechanical, and optical properties of graphene as well as the ease of functionalization of its derivates have enabled graphene to become an attractive candidate for the construction of flexible devices. This paper provides a comprehensive review about the most recent progress in the synthesis and applications of graphene-based composites. Composite materials based on graphene, graphene oxide (GO), and reduced graphene oxide (rGO), as well as conducting polymers, metal matrices, carbon–carbon matrices, and natural fibers have potential application in energy-harvesting systems, clean-energy storage devices, and wearable and portable electronics owing to their superior mechanical strength, conductivity, and extraordinary thermal stability. Additionally, the difficulties and challenges in the current development of graphene are summarized and indicated. This review provides a comprehensive and useful database for further innovation of graphene-based composite materials.

Flash memory has become a ubiquitous solid-state memory device widely used in portable digital devices, computers and enterprise applications. The development of the information age has demanded improvements in memory speed and retention performance. Here we demonstrate an ultrafast non-volatile flash memory based on MoS 2 /hBN/multilayer graphene van der Waals heterostructures, which achieves an ultrafast writing/erasing speed of 20 ns through two-triangle-barrier modified Fowler–Nordheim tunnelling. Using detailed theoretical analysis and experimental verification, we postulate that a suitable barrier height, gate coupling ratio and clean interface are the main reasons for the breakthrough writing/erasing speed of our flash memory devices. Because of its non-volatility this ultrafast flash memory could provide the foundation for the next generation of high-speed non-volatile memory. MoS 2 /hBN/graphene van der Waals heterostructures with a clean interface and optimized barrier height and gate coupling ratio enable the realization of ultrafast non-volatile flash memory.

Flexible reduced graphene oxide (rGO) sheets are being considered for applications in portable electrical devices and flexible energy storage systems. However, the poor mechanical properties and electrical conductivities of rGO sheets are limiting factors for the development of such devices. Here we use MXene (M) nanosheets to functionalize graphene oxide platelets through Ti-O-C covalent bonding to obtain MrGO sheets. A MrGO sheet was crosslinked by a conjugated molecule (1-aminopyrene-disuccinimidyl suberate, AD). The incorporation of MXene nanosheets and AD molecules reduces the voids within the graphene sheet and improves the alignment of graphene platelets, resulting in much higher compactness and high toughness. In situ Raman spectroscopy and molecular dynamics simulations reveal the synergistic interfacial interaction mechanisms of Ti-O-C covalent bonding, sliding of MXene nanosheets, and π-π bridging. Furthermore, a supercapacitor based on our super-tough MXene-functionalized graphene sheets provides a combination of energy and power densities that are high for flexible supercapacitors. Poor mechanical properties of reduced graphene oxide sheets hinder development of flexible energy storage systems. MXene functionalised graphene oxide with Ti-O-C bonding and additional crosslinking is here reported to dramatically increase toughness for flexible supercapacitors.

Electrochemical biosensors incorporate a recognition element and an electronic transducer for the highly sensitive detection of analytes in body fluids. Importantly, they can provide rapid readouts and they can be integrated into portable, wearable and implantable devices for point-of-care diagnostics; for example, the personal glucose meter enables at-home assessment of blood glucose levels, greatly improving the management of diabetes. In this Review, we discuss the principles of electrochemical biosensing and the design of electrochemical biosensor devices for health monitoring and disease diagnostics, with a particular focus on device integration into wearable, portable and implantable systems. Finally, we outline the key engineering challenges that need to be addressed to improve sensing accuracy, enable multiplexing and one-step processes, and integrate electrochemical biosensing devices in digital health-care pathways.Electrochemical biosensors can be integrated into wearable, portable and implantable devices for health monitoring and disease diagnosis. This Review discusses the design and integration of different types of electrochemical biosensors for the detection of analytes related to health and disease, and outlines engineering challenges that need to be addressed to enable clinical translation of electrochemical biosensor-based point-of-care devices.

Lithium cobalt oxide, as a popular cathode in portable devices, delivers only half of its theoretical capacity in commercial lithium-ion batteries. When increasing the cut-off voltage to release more capacity, solubilization of cobalt in the electrolyte and structural disorders of lithium cobalt oxide particles are severe, leading to rapid capacity fading and limited cycle life. Here, we show a class of ternary lithium, aluminum, fluorine-modified lithium cobalt oxide with a stable and conductive layer using a facile and scalable hydrothermal-assisted, hybrid surface treatment. Such surface treatment hinders direct contact between liquid electrolytes and lithium cobalt oxide particles, which reduces the loss of active cobalt. It also forms a thin doping layer that consists of a lithium-aluminum-cobalt-oxide-fluorine solid solution, which suppresses the phase transition of lithium cobalt oxide when operated at voltages >4.55 V. LiCoO 2 is a cathode material widely used in lithium-ion batteries but suffers from solubilization of cobalt and structural disorder when the voltage is increased to release more capacity. Here the authors show a ternary Li, Al and F-modified LiCoO 2 and battery cells with stable cycling behavior over 4.55 V.

Due to inherently poor healable and stretchable features, the most explored polyvinyl alcohol-based gel electrolytes cannot well meet the requirements of stretchable, healable and multifunctional supercapacitors. Here, we report a hydrogel of a copolymer cross-linked by double linkers of Laponite (synthetic hectorite-type clay) and graphene oxide. The resultant hydrogel shows high mechanical stretchability, excellent ionic conductivity, and superior healable performance. Along with designing wrinkled-structure electrodes, supercapacitors fabricated by using this hydrogel as a gel electrolyte not only exhibit ultrahigh mechanical stretchability of 1000%, but also achieve repeated healable performance under treatments of both infrared light irradiation and heating. More significantly, a broken/healed supercapacitor also possesses an ultrahigh stretchability up to 900% with slight performance decay. This hydrogel electrolyte could be easily functionalized by introducing other functional components, and extended for use in other portable and wearable energy related devices with multifunction. Healable and stretchable energy storage devices are gaining interest for wearable electronics and smart textiles. Here the authors report a nanocomposite hydrogel with high stretchability, ionic conductivity, and healing capability for use in a supercapacitor that can stretch 900% after healing.

Due to the use of the new line and the new station area, the existing tower naming plate has not met the requirements of the latest specification, and it is urgent to replace it in batches, but the traditional naming plate pasting work must be carried out manually throughout the whole process, which is time-consuming and laborious, and the efficiency is low. In order to solve the above problems, a portable retractable tower naming plate pasting device was developed to improve the on-site pasting working mode, and the device integrates a fixed fixture, a cleaning brush, and a retractable insulating rod in one, and has the characteristics of portability and high efficiency. It has been proved in practice that the developed device can effectively reduce the unqualified rate of pasting and improve work efficiency, and effectively improve quality and efficiency.