Publications by authors named "Yazhen Shen"

Controlled-release fertilizers (CRFs) with long release longevity have been actively sought to match the nutrient demands of crops over the entire growing period. Waterborne polymer is an environmental friendliness coating for CRFs because it neither uses organic solvent nor influences soil property. However, its low hydrophobicity leads to a short controlled-release longevity of CRFs coated with waterborne polymer.

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Soils are crucial trace evidence that can establish or exclude the relationship between a suspect, victim, or an object at a particular scene, which could contribute to building a case. Laser-induced breakdown spectroscopy (LIBS) and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy have been demonstrated to be effective techniques for soil characterization owing to its being rapid, non-destructive, and convenient analysis with little sample preparation requirements. Therefore, the principles of LIBS and FTIR-ATR techniques for soil forensic analysis in typical soil samples were investigated and their practical feasibility was tested by applying the techniques to forensic soil samples in two criminal cases.

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Cuticle is the first barrier for rice to resist blast fungus on the surface of the leaf. Studies on how the rice leaf cuticle responds to rice blast and attempts to perform early detection of rice blast are limited, and these two issues were explored in this study via depth-profiling Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS). Rice leaves with four different scales of injury (healthy leaves as CK, asymptomatic leaves from mildly diseased seedlings as S1, infected leaves with fewer than five lesions as S2, and infected leaves with more than 10 lesions as S3) were scanned by three moving mirror velocities 0.

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Plant cuticle is an important interface on the outmost region of plant and will make the response to environmental changes. However, research about how the variable nutritional status affect plant cuticle is limited. This was the first report about the manners of rice leaf cuticle in answer to different nutritional circumstances of nitrogen detected by the Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) which with a main superiority for in situ and depth-profiling in mid-infrared range.

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Although polymer-coated controlled-release fertilizers have been under development for decades, their high costs, complex production processes, and potential environmental hazards have limited their application. Therefore, it is necessary to design and develop new materials for controlled nutrient release. In this study, two novel MOFs, compounds I and II, were successfully fabricated and optimized using ferric chloride, phosphoric acid, citric acid, and urea under hydrothermal conditions.

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Background: An effective and expeditious approach to assess plant nitrogen status is urgently needed in rice production and management as the conventional chemical methods are laborious and time-consuming.

Results: Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was used to record the spectra of rice leaves for the effective diagnosis of nitrogen nutrition status. The band in the wavenumber range of 1680 to 1630 cm was associated with amide I and that from 1570 to 1510 cm with amide II.

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The behavior of a metal-organic framework (MOF) compound synthesized in hydrothermal reaction conditions and rich in N, P, and Fe nutrients was explored in the field. The attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy and laser induced breakdown spectroscopy (LIBS) characterization results showed that the chemical structures changed during the degradation process in crop field soil. The scanning electron microscope images showed that the micro-rod of the MOF peeled off and degraded in layers.

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Recently, polyacrylates (PA) have been applied in coated controlled-release fertilizer (CRF), but the impacts of the soil on the degradation of PA have not been evaluated. In this study, an outdoor agriculture soil buried test was carried out for 12 months to investigate the degradation of PA films. The residual degraded films were taken regularly from the soil and analyzed by SEM, Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) and laser-induced breakdown spectroscopy (LIBS).

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Development of controlled-release urea (CRU) has attracted research attention because of food scarcity problems and environmental concerns. To slow down the nutrient release of CRU coated with waterborne polyacrylate, conventional emulsion polymerization (CEP), conventional emulsion polymerization containing hexadecane (CEP + HD), and miniemulsion polymerization (MP) were carried out to discern the influence of polymerization technique and hexadecane on the properties of emulsions, films, and on the resultant nutrient release profiles of controlled-release urea. The addition of hexadecane improved water resistance, decreased the glass-transition temperature, and slowed down the nutrient release.

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Detection of pesticide residues is important for ensuring food safety, and it has assumed increased significance. Traditional analytical methods are known for being destructive and cost- and time-intensive. In this study, depth-profiling Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was successfully used as an in situ, nondestructive, and rapid method for detecting tricyclazole residues on three metal surfaces (copper, aluminum, and iron) and subsequently, on the surfaces of fresh rice leaves and ripe husks.

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Acrylic latexes are valuable waterborne materials used in controlled-release fertilizers. Controlled-release urea coated with these latexes releases a large amount of nutrients, making it difficult to meet the requirement of plants. Herein, Fe-tannic acid (TA) complexes were blended with acrylic latex and subsequently reassembled on a surface of polyacrylate particles.

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Understanding nitrogen (N) status in the leaves of Chinese cabbage (Brassica rapa subsp. chinensis) is of significance to both vegetable growth and quality control. Fourier transform infrared photoacoustic spectroscopy was used to perform rapid qualification of N distribution in leaves; a partial least squares algorithm was used to develop a model for prediction of the N content; and N distribution in individual leaves was mapped on the basis of interpolation analysis, which was found to be variable.

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Article Synopsis
  • Raman spectroscopy is less popular in soil analysis compared to infrared spectroscopy due to interference from fluorescence.
  • This study tested the effectiveness of combining Fourier-transform infrared photoacoustic (FTIR-PAS) and Raman spectroscopies with partial least squares regression (PLSR) to predict soil organic matter (SOM) using 194 soil samples.
  • Results indicated that while both techniques individually predicted SOM accurately, the combined approach improved prediction accuracy significantly, suggesting it could be a valuable method for soil characterization.
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Article Synopsis
  • Controlled-release fertilizers (CRF) enhance nutrient efficiency for crops, but the impact of thermal post-treatments on nutrient release is not fully understood.
  • Researchers tested a polyacrylate-coated CRF at various temperatures (30°C, 60°C, 80°C) and durations (2-24 hours) to analyze nutrient release mechanisms using advanced microscopy and spectroscopy techniques.
  • Results showed that higher post-treatment temperatures and longer durations improved nutrient release efficiency by creating a more compact and smoother membrane, ultimately allowing for better optimization of CRF for agricultural use.
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  • Biochar-modified polyacrylate-like polymers are effective as membrane coatings for controlled-release fertilizers but their impact on paddy soil remains unclear.
  • A study utilized advanced techniques to observe the behavior of these polymers in the soil and their influence on soil bacteria.
  • Results indicated that the biochar-modified membranes biodegrade slower and maintain integrity longer, which enhances nutrient release, while initially reducing microbial activity, but allowing recovery over time.
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The acrylate-like materials were used to develop the polymer coated controlled release fertilizer, the nutrients release profiles were determined, meanwhile the Fourier transform mid-infrared photoacoustic spectra of the coatings were recorded and characterized; GRNN model was used to predict the nutrients release profiles using the principal components of the mid-infrared photoacoustic spectra as input. Results showed that the GRNN model could fast and effectively predict the nutrient release profiles, and the predicted calibration coefficients were more than 0.93; on the whole, the prediction errors (RMSE) were influenced by the profiling depth of the spectra, the average prediction error was 10.

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