A remote Laser Induced Breakdown Spectroscopy (LIBS) detection system is developed which enables scanning of a 2-dimensional area with a maximum distance of 30 meters. We applied it on leaves in-situ ...elemental analysis.
Carbonate rocks, mainly limestone and dolostone, have made up 10% to 15% of sedimentary rocks in the Earth. Geochemical contents of carbonate rocks could reflect a series of key geological ...information of ancient environment, such as temperature, precipitation, salinity and geologic event. Stand-off LIBS provides an approach to rapidly, accurately and nondestructively determine the elemental concentrations in difficult carbonate rock samples, such as cliff rocks, small reefs and karst caves. In this study, we have determined Mg/Ca ratio and Sr/Ca ratio in either limestones from Xinjiang, Guangdong, Hunan or dolostones from Yunnan at a distance of 15 meters. 2D Mapping data of Mg/Ca and Sr/Ca ratios of rocks from Yunnan clearly exhibit spatial variation of geochemical contents. These variations are correlated to the temperature changes along the geologic times, which has been proved to influence the Magnesium incorporation of rocks.
The authors have developed an integrated remote laser-induced breakdown spectroscopy (LIBS) and Raman spectroscopy system for measuring both LIBS and Raman spectra. The system has been used for ...analyzing both Raman and LIBS spectra of minerals in air. These experiments demonstrate that by focusing a 532nm Nd:YAG pulsed laser beam with a 5× beam expander to a 1.5 mm diameter spot on a sample surface located at 15 meters away, it is possible to identify the compositions of the sample by using this remote LIBS and Raman spectrum detection system.
In this study, a particle swarm optimization (PSO) algorithm was implemented to quantitatively analyze the Lead (Pb) concentration in water. Thirty-five samples with different concentrations of Pb(NO ...3 ) 2 were detected by laser-induced breakdown spectroscopy (LIBS). The strong spectral line of 405.78 nm was selected as the analytical line. The PSO algorithm was created, trained and tested by I Pb . The results have shown that PSO algorithm has many advantages. The Mean Relative Error Percentage (MREP) and the Relative Standard Deviation (RSD) of the test results obtained by PSO algorithm are better than those obtained by Genetic Algorithms (GA) and Ant Colony Optimization algorithm (ACO).
A single atomic slice of {\alpha}-tin-stanene-has been predicted to host quantum spin Hall effect at room temperature, offering an ideal platform to study low-dimensional and topological physics. ...While recent research has intensively focused on monolayer stanene, the quantum size effect in few-layer stanene could profoundly change material properties, but remains unexplored. By exploring the layer degree of freedom, we unexpectedly discover superconductivity in few-layer stanene down to a bilayer grown on PbTe, while bulk {\alpha}-tin is not superconductive. Through substrate engineering, we further realize a transition from a single-band to a two-band superconductor with a doubling of the transition temperature. In-situ angle resolved photoemission spectroscopy (ARPES) together with first-principles calculations elucidate the corresponding band structure. Interestingly, the theory also indicates the existence of a topologically nontrivial band. Our experimental findings open up novel strategies for constructing two-dimensional topological superconductors.
In the experimental condition, Pteridium aquilinum Net photosynthetic rate increase by Photosynthetic active Radiation increasing before it reach Light saturation point, Light compensation points and ...Light saturation point are even lower, that is partly 50μmol·m -2 ·s -1 and 400μmol·m -2 ·s -1 . It tells Pteridium aquilinum has character of shade plants. Some measures should be considered in the practical production.
Complex activity recognition is a valuable issue in mobile and wearable computing. Since complex activities are strongly relevant to users' locations, location data can be used in complex activity ...recognition. Current activity recognition methods utilizing location data either do not make the most of location data or have a "cold-start" problem. In this paper, we propose CAROLINA (complex activity recognition using acceleration, vital sign, and location data) to recognize complex activities from wearable sensors. CAROLINA divides a map into grid cells and builds a grid cell-activity matrix by integrating check-in and ATUS (American Time Use Survey) datasets. Since some grid cells do not have check-in records, there are some null entries in the matrix, and all the entries are reconstructed by matrix factorization. Meanwhile, a POI (point of interest) category dataset is exploited to build a grid cell-grid cell similarity matrix, which is used to reduce the loss of matrix factorization. The results of experiments show that CAROLINA can effectively utilize location data to improve complex activity recognition performance.
Quantum computers are based on the theory of quantum mechanics, and their powerful parallel data processing capability is expected to solve many mathematical problems that too are difficult to be ...handled by classical computers. Especially with the increase of data processing volume, the quantum advantage is more obvious. Among the many physical systems for quantum computers, superconducting quantum circuit and semiconductor quantum dot computers show amazing potential due to their compatibility with traditional integrated circuit process technology and ultrashort gating time of nanoseconds. Superconducting qubits consisting of Josephson junctions and superconducting coplanar capacitors are easily integrated into a large scale for their simple circuit structure and conventional semiconductor process compatibility. Semiconductor qubits made from isotopically purified silicon (Si)-based materials greatly suppress nuclear spin noise, and decoherence times of ultralong milliseconds can be achieved. In this article, we systematically describe the challenges faced by superconducting qubits and semiconductor qubits in hot issues such as error correction and decoherence and look into the future development of superconducting quantum computers and Si-based semiconductor quantum computers.
