Spectral filtering method for improvement of detection accuracy of Mg, Cu, Mn and Cr elements in aluminum alloys using femtosecond LIBS.

In this work, magnesium (Mg), copper (Cu), manganese (Mn) and chromium (Cr) in aluminum alloy samples were quantified by femtosecond laser-induced breakdown spectroscopy (fs-LIBS). The different parameters affecting the experimental results, including the laser pulse energy, moving speed of the 2D platform and spectral average number were optimized. The background signal preprocessing methods of median filtering (MF corrected) and Savitzky-Golay filtering (SG corrected) algorithms were used and the effect of the LIBS spectral analysis in the experiment investigated.

Feasibility Analysis and Implementation of Head-Mounted Electrical Impedance Respiratory Monitoring.

The respiratory rate is one of the crucial indicators for monitoring human physiological health. The purpose of this paper was to introduce a head-mounted respiratory monitoring solution based on electrical impedance sensing. Firstly, we constructed a finite element model to analyze the feasibility of using head impedance for respiratory sensing based on the physiological changes in the pharynx.

A novel indicator for defining plain urban river network cyanobacterial blooms: resource use efficiency.

Increasing eutrophication and climate change have led to heavy cyanobacterial blooms in water diversion sources (e.g., lakes, reservoirs), which can potentially cause algae-bearing water to spread to downstream to an urban river network via diversion channels.

[Ten-year Trend Analysis of Eutrophication Status and the Related Causes in Lake Hongze].

In order to propose pertinent suggestions regarding eutrophication control for Lake Hongze, we used monthly monitoring data from 2011 to 2020 to elucidate the spatiotemporal changing characteristics of eutrophic status and the relevant driving factors. As the main river entering Lake Hongze, River Huaihe experienced an increase in permanganate index and a decrease in TN in the last 10 years. Meanwhile, Secchi depth, TP, and permanganate index increased, whereas TN and Chl-a concentration decreased significantly in Lake Hongze.

Lake ecosystem health assessment using a novel hybrid decision-making framework in the Nam Co, Qinghai-Tibet Plateau.

Lake health assessment (LHA), a powerful tool for lake ecological protection, provides the foundation for sustainable water environment management. However, existing methods have not yet considered the effects of fuzziness and randomness on LHA. In addition, most of the current studies on LHA focus on the plain areas, lack of quantitative studies in mountain areas, such as the Qinghai-Tibet Plateau.

Splicing point tapered fiber Mach-Zehnder interferometer for simultaneous measurement of temperature and salinity in seawater.

Combined with non-adiabatic tapering and mode field mismatch between two different fibers, a splicing point tapered fiber Mach-Zehnder interferometer is proposed. Theoretically, two sensing units are carefully designed for dual-parameter sensing, and mode exciting and evolution in fibers are analyzed and shown dynamically. In experiment, transmission spectrum is obtained with two sets of clear interference as designed.

Ultrasensitive optical sensing in aqueous solution based on microfiber modal interferometer.

In this paper, an ultrahigh sensitivity sensing in aqueous solution for microfiber modal interferometer (MMI) is realized. The group refractive index (RI) difference between HE and HE mode will come down to 0 at a certain wavelength, resulting in ultrahigh sensitivity near this wavelength. MMI with different diameters have their individual ultrasensitive wavelength band, which indicates the broad range of optional probing wavelength and more liberal diameter condition on fiber fabrication.

Prenatal Perfluorooctyl Sulfonate Exposure and Alu DNA Hypomethylation in Cord Blood.

Background: Perfluoroalkyl substances (PFASs) are stable and persistent in the environment, animals, and humans. PFASs can penetrate placenta and affect fetal growth. We investigated associations between prenatal exposure to perfluorooctanoic acid (PFOA), perfluorooctyl sulfonate (PFOS), perfluorononanoic acid (PFNA), and perfluoroundecanoic acid (PFUA) and global methylation levels.

All-fiber Mach-Zehnder interferometer for tunable two quasi-continuous points' temperature sensing in seawater.

An all-fiber Mach-Zehnder interferometer (MZI) for two quasi-continuous points' temperature sensing in seawater is proposed. Based on the beam propagation theory, transmission spectrum is designed to present two sets of clear and independent interferences. Following this design, MZI is fabricated and two points' temperature sensing in seawater are demonstrated with sensitivities of 42.

[Analysis of Microfiber Knot Resonator Spectrum for Seawater Temperature].

As a sensing device, microfiber knot resonator (MKR) has been widely used in sensing field due to its advantages of high sensitivity and fast response. It is important to analyze the spectrum of MKR for detecting environmental parameters in that the spectrum can reflect the change of ambient environment. In this paper, the relationship between spectrum of MKR and seawater temperature has been studied theoretically and experimentally.

Modeling seawater salinity and temperature sensing based on directional coupler assembled by polyimide-coated micro/nanofibers.

The salinity and temperature of seawater are important parameters in oceanography. Based on the directional coupler assembled by polyimide-coated micro/nanofibers, optical sensors with high sensitivity for simultaneous salinity and temperature sensing in seawater are proposed. Dependences of sensitivities on wavelength, salinity, and temperature are investigated theoretically, with which performances of such sensor under general sea conditions can be evaluated.

[Near Infrared Spectroscopy of the Cretaceous Red Beds in Inner Mongolia Dongshengmiao].

Take the cores and surface weathered soil from the Cretaceous red beds in the western of Dongshengmiao mine of Inner Mongolia and analysis with near-infrared spectroscopy. The result shows that near-infrared spectroscopy can identify mineral quickly through the characteristic absorption peaks of each group. The Cretaceous red beds in the western of Dongshengmiao mine is argillaceous cementation, it is mainly composed of quartz, feldspar, montmorillonite, illite, chlorite, muscovite etc, the mineral composition is mainly affected by the upstream source area.

[Near infrared spectrum analysis and meaning of the soil in 512 earthquake surface rupture zone in Pingtong, Sichuan].

Through modern near infrared spectrum, the authors analyzed the yellow soil from the rupture zone located in Ping- tong town,Pingwu, Sichuan province. By rapid identification of the characteristic of peak absorption of mineral particles, the result shows that the soil samples mainly composed of calcite, dolomite, muscovite, sericite, illite, smectite; talc, tremolite, actinolite, chlorite, etc. And the mineral compositions of the soil is basically the same with the yellow soil in Sichuan region.

Temperature sensing in seawater based on microfiber knot resonator.

Ocean internal-wave phenomena occur with the variation in seawater vertical temperature, and most internal-wave detections are dependent on the measurement of seawater vertical temperature. A seawater temperature sensor based on a microfiber knot resonator (MKR) is designed theoretically and demonstrated experimentally in this paper. Especially, the dependences of sensing sensitivity on fiber diameter and probing wavelength are studied.

[X-ray diffraction and infrared spectrum analysis of fault gouge in Wenchuan seismic belt].

Wenchuan earthquake produced a series of co-seismic surface ruptures in Leigu and Zhaojiagou, and we collected samples of co-seismic fault gouge in the surface ruptures as well as the old gouge in the fault of Nanba. Testing The new and old fault gouge was tested with X-ray diffraction and infrared absorption spectra, and its characteristics such as mineral compositions, clay mineral contents and combinations were comprehensively analyzed. The results display obvious differences between the new and old fault gouge, showing that the old fault gouge is mainly composed of wall rock debris or milled powders, while the main components of new fault gouge are clay minerals.