When a high-powered laser beam is focused onto a small area or spot of a solid surface, the temperature of the locally heated region rises rapidly to the vaporization temperature of the solid material and an optically induced plasma, frequently called a laser-induced plasma (LIP) or laser-ablated plasma (LAP) or laser spark is formed at the surface. The plasma will be formed when the laser power density exceeds the breakdown threshold value of the solid surface. Although different materials have different breakdown thresholds, an optical plasma is produced when the laser power density exceeds several megawatts per centimeter squared (10⁶ - 10⁹ W/cm²). This plasma has been used for sampling, atomization, excitation, and ionization in analyhcal atomic spectroscopy. It has also been frequently used and proposed as a source for atomic emission spectrometry (AES). In this case the technique is most ofien referred to as laser microprobe optical emission spectrometry (LM-OES) developed by Brech and Cross [1] in early nineteen-sixties or more recently called laser-induced breakdown spectrometry (LIBS) [2,3]. Generally, this analyhcal technique involves two steps; the pulsed focused laser beam directed into a gaseous sample or the surface of a solid or liquid, to produce a transient LIP, followed by the measurement of a characteristic atomic emission signal related to some species present in the plasma. The LIP formed is tightly focused and consists of vaporized atoms, ions, electrons, and molecular fragments. The application of LIBS for direct spectrochemical analysis is a rapidly growing field ranging from the detection of atmospheric pollutants to monitoring of material production processes, and even to “clean-room” technology. Laser ablation techniques have also been applied for solid sample introduction into other plasma sources [4–9]. In recent years, the powerful technique of LIBS as an analytical tool has been recognized by a number of research groups, and has led to an increasing number of publications on the applications of LIBS both in the laboratory and in industry. This growing success of LIBS is a result of thorough research carried out to understand the related plasma physical processes, aided by marked improvements in laser systems and photodetector technology.

Highly sensitive hydrogen sulfide (H₂S) gas sensors were developed from CuO-decorated ZnO semiconducting hierarchical nanostructures. The ZnO hierarchical nanostructure was fabricated by an electrospinning method following hydrothermal and heat treatment. CuO decoration of ZnO hierarchical structures was carried out by a wet method. The H₂S gas-sensing properties were examined at different working temperatures using various quantities of CuO as the variable. CuO decoration of the ZnO hierarchical structure was observed to promote sensitivity for H₂S gas higher than 30 times at low working temperature (200 °C) compared with that in the nondecorated hierarchical structure. The sensing mechanism of the hybrid sensor structure is also discussed. The morphology and characteristics of the samples were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis absorption, photoluminescence (PL), and electrical measurements.

The use of laser‐induced breakdown spectrometry (LIBS) has grown steadily, and it has proven to be a relatively dynamic research activity for performing direct spectrochemical elemental or metal analysis of a variety of materials, solids, liquids, and gases, with none or little sample pretreatment procedures. Significant progress has been made during the last several years on the diverse and versatile applications of LIBS including remote material analysis in nuclear power stations, space exploration, diagnostics of archaeological objects, and metal diffusion in solar cells, etc. This review presents the more recent applications of LIBS based on the development of fiber‐optic (FO) technology and portable instrumentation. The characteristics of matrices, object of analysis, laser system used, and analytical performances are tabulated for metallurgical samples, liquid and colloid samples, aerosol and gases, environmental samples, non‐metallic solids, advanced materials, and miscellaneous applications.

The efficient and selective delivery of therapeutic drugs to the target site remains the main obstacle in the development of new drugs and therapeutic interventions. Up until today, nanomicelles have shown their prospective as nanocarriers for drug delivery owing to their small size, good biocompatibility, and capacity to effectively entrap lipophilic drugs in their core. Nanomicelles are formed via self-assembly in aqueous media of amphiphilic molecules into well-organized supramolecular structures. Molecular weights and structure of the core and corona forming blocks are important properties that will determine the size of nanomicelles and their shape. Selective delivery is achieved via novel design of various stimuli-responsive nanomicelles that release drugs based on endogenous or exogenous stimulations such as pH, temperature, ultrasound, light, redox potential, and others. This review summarizes the emerging micellar nanocarriers developed with various designs, their outstanding properties, and underlying principles that grant targeted and continuous drug delivery. Finally, future perspectives, and challenges for nanomicelles are discussed based on the current achievements and remaining issues.