In the field of dual-pulse laser-induced breakdown spectroscopy(DP-LIBS)research,the pursuit of methods for determining pulse intervals and other parameters quickly and conveniently in order to achieve optimal spectra...In the field of dual-pulse laser-induced breakdown spectroscopy(DP-LIBS)research,the pursuit of methods for determining pulse intervals and other parameters quickly and conveniently in order to achieve optimal spectral signal enhancement is paramount.To aid researchers in identification of optimal signal enhancement conditions and more accurate interpretation of the underlying signal enhancement mechanisms,theoretical simulations of the spatiotemporal processes of coaxial DP-LIBS-induced plasma have been established in this work.Using a model based on laser ablation and two-dimensional axisymmetric fluid dynamics,plasma evolutions during aluminum–magnesium alloy laser ablation under single-pulse and coaxial dualpulse excitations have been simulated.The influences of factors,such as delay time,laser fluence,plasma temperature,and particle number density,on the DP-LIBS spectral signals are investigated.Under pulse intervals ranging from 50 to 1500 ns,the time evolutions of spectral line intensity,dual-pulse emission enhancement relative to the single-pulse results,laser irradiance,spatial distribution of plasma temperature and species number density,as well as laser irradiance shielded by plasma have been obtained.The study indicates that the main reason behind the radiation signal enhancement in coaxial DP-LIBS-induced plasma is attributed to the increased species number density and plasma temperature caused by the second laser,and it is inferred that the shielding effect of the plasma mainly occurs in the boundary layer of the stagnation point flow over the target surface.This research provides a theoretical basis for experimental research,parameter optimization,and signal enhancement tracing in DP-LIBS.展开更多
With the rapid advancement of laser decontamination technology and growing awareness of microbial hazards,it becomes crucial to employ theoretical model to simulate and evaluate decontamination processes by laser-indu...With the rapid advancement of laser decontamination technology and growing awareness of microbial hazards,it becomes crucial to employ theoretical model to simulate and evaluate decontamination processes by laser-induced plasma.This study employs a two-dimensional axisymmetric fluid dynamics model to simulate the power density of plasma bombardment on bacteria and access its decontamination effects.The model considers the transport processes of vapor plasma and background gas molecules.Based on the destructive impact of high-speed moving particles in the plasma on bacteria,we investigate the bombardment power density under various conditions,including different laser spot sizes,wavelengths,plate's tilt angles,and plate-target spacing.The results reveal that the bombardment power density increases with a decrease in laser spot size and wavelength.For instance,when the plate is parallel to the target surface with a 1 mm spacing,the bombardment power density triples as the laser spot size decreases from 0.8 mm to 0.5 mm and quadruples as the wavelength decreases from 1064 nm to 266 nm.Notably,when the plate is parallel to the target with a relatively close spacing of 0.5 mm,the bombardment power density at 0°inclination increases sevenfold compared to 45°.This simulation study is essential for optimizing optical parameters and designing component layouts in decontamination devices using laser-induced plasma.The reduction of laser spot size,wavelength,plate-target spacing and aligning the plate parallel to the target,collectively contribute to achieving precise and effective decontamination.展开更多
Objectives: The existing inflammatory models are concentrated in relatively complex medical fields, and most of them use a single type of cell, and the induction conditions are not uniform, so the current LPS-induced ...Objectives: The existing inflammatory models are concentrated in relatively complex medical fields, and most of them use a single type of cell, and the induction conditions are not uniform, so the current LPS-induced inflammation model is less conducive to the study of skin inflammation. The aim of this research is to enhance the existing LPS-induced inflammation model and establish a skin inflammation model that is suitable for the swift screening of anti-inflammatory agents in the cosmetics industry. Methods: LPS was used to induce inflammatory responses in KC and THP-1 cells. Enzyme-linked immunosorbent assay (ELISA) was employed to assess the levels of IL-1α, IL-8, and TNF-α in the two cell types, while the DCFH-DA probe was utilized to label the levels of reactive oxygen species (ROS) in both cell types. Results: In KC cells, 10 μg/mL of LPS induced a significant upregulation of IL-8 but did not result in elevated expression of IL-1α. However, at 100 μg/mL of LPS, both IL-8 and IL-1α were highly expressed in KC cells. LPS concentrations ranging from 0.01 to 100 μg/mL failed to stimulate TNF-α production in KC cells but induced a gradient increase in ROS levels. In THP-1 cells, LPS concentrations from 0.01 to 100 μg/mL did not induce IL-1α production but significantly elevated IL-8 and led to a gradient increase in TNF-α and ROS. After treatment with 100 μg/mL of LPS, the cosmetic ingredient Rucika KGM mitigated the elevated levels of IL-1α, IL-8, and ROS in LPS-induced KC cells and IL-8 and ROS in THP-1 cells. Conclusion: This study has successfully developed an application-oriented model suitable for investigating skin inflammation, enabling the rapid and comprehensive screening of cosmetic ingredients with anti-inflammatory activity. .展开更多
Cord fabric is a critical material used in the manufacture of tyres and various composite materials to increase durability and strength. The tyre consists of many layers of cord fabric, with each layer being referred ...Cord fabric is a critical material used in the manufacture of tyres and various composite materials to increase durability and strength. The tyre consists of many layers of cord fabric, with each layer being referred to as a cord ply. These layers are strategically positioned within the tyre’s internal structure, particularly in the tread and sidewall areas, to improve handling, durability and impact resistance. The cord fabric also serves a critical role in maintaining the structural integrity of the tyre, ensuring that it retains its contour and resists deformations under different operating conditions. This study discusses the advantages and disadvantages of using Nylon 6 (NY6) and Nylon 66 (NY66) cord fabrics in scooter tire production, with a focus on their mechanical behavior under varying curing temperatures and pressures. It was observed that while the curing time for both NY6 and NY66 remained consistent across different platen temperatures and pressures, their mechanical properties showed significant differences. NY6, known for its flexibility and impact resistance, exhibited greater changes in cord-breaking strength and elongation with increasing temperature, showing a marked decrease in breaking strength at higher temperatures. In contrast, NY66 maintained better stability and performance under similar conditions.展开更多
Antiozonants and antioxidants are additives commonly used in the rubber industry to enhance the durability and performance of rubber products. Ozone, present in the atmosphere, can cause rubber to degrade over time th...Antiozonants and antioxidants are additives commonly used in the rubber industry to enhance the durability and performance of rubber products. Ozone, present in the atmosphere, can cause rubber to degrade over time through a process known as ozone cracking. These rubber additives are added to rubber compounds to protect against this degradation. They work by reacting with ozone, preventing it from attacking and breaking the molecular chains in the rubber, helping to maintain the structural integrity of the rubber product. It is now well known that 6PPD contributes to the extension of the service life of rubber products. However, recent studies have shown that 6PPD can be harmful to the environment, especially when end-of-life tyres (ELTs) are contaminated with the water. With the effect of ozone, 6PPD is converted to 6PPD quinone, which is toxic enough to kill some sensitive fish species such as Coho Salmon (Oncorhynchus kisutch). This study drew attention to new chemical compounds and natural products that can be used as antiozonants and antioxidants in the rubber industry instead of 6PPD. Although the scientific studies are promising, the fact that 6PPD is still used in production shows that more scientific studies and social awareness need to be developed in this area.展开更多
基金supported by the National Key R&D Program of China (No. 2017YFA0304203)the National Energy R&D Center of Petroleum Refining Technology (RIPP, SINOPEC)+3 种基金Changjiang Scholars and Innovative Research Team at the University of the Ministry of Education of China (No. IRT_17R70)National Natural Science Foundation of China (NSFC) (Nos. 61975103, 61875108 and 627010407)111 Project (No. D18001)Fund for Shanxi (No. 1331KSC)
文摘In the field of dual-pulse laser-induced breakdown spectroscopy(DP-LIBS)research,the pursuit of methods for determining pulse intervals and other parameters quickly and conveniently in order to achieve optimal spectral signal enhancement is paramount.To aid researchers in identification of optimal signal enhancement conditions and more accurate interpretation of the underlying signal enhancement mechanisms,theoretical simulations of the spatiotemporal processes of coaxial DP-LIBS-induced plasma have been established in this work.Using a model based on laser ablation and two-dimensional axisymmetric fluid dynamics,plasma evolutions during aluminum–magnesium alloy laser ablation under single-pulse and coaxial dualpulse excitations have been simulated.The influences of factors,such as delay time,laser fluence,plasma temperature,and particle number density,on the DP-LIBS spectral signals are investigated.Under pulse intervals ranging from 50 to 1500 ns,the time evolutions of spectral line intensity,dual-pulse emission enhancement relative to the single-pulse results,laser irradiance,spatial distribution of plasma temperature and species number density,as well as laser irradiance shielded by plasma have been obtained.The study indicates that the main reason behind the radiation signal enhancement in coaxial DP-LIBS-induced plasma is attributed to the increased species number density and plasma temperature caused by the second laser,and it is inferred that the shielding effect of the plasma mainly occurs in the boundary layer of the stagnation point flow over the target surface.This research provides a theoretical basis for experimental research,parameter optimization,and signal enhancement tracing in DP-LIBS.
基金supported by National Key R&D Program of China(No.2017YFA0304203)National Energy R&D Center of Petroleum Refining Technology(RIPP,SINOPEC),Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China(No.IRT_17R70)+2 种基金National Natural Science Foundation of China(Nos.12374377,61975103 and 627010407)111 Project(No.D18001)Fund for Shanxi‘1331KSC’。
文摘With the rapid advancement of laser decontamination technology and growing awareness of microbial hazards,it becomes crucial to employ theoretical model to simulate and evaluate decontamination processes by laser-induced plasma.This study employs a two-dimensional axisymmetric fluid dynamics model to simulate the power density of plasma bombardment on bacteria and access its decontamination effects.The model considers the transport processes of vapor plasma and background gas molecules.Based on the destructive impact of high-speed moving particles in the plasma on bacteria,we investigate the bombardment power density under various conditions,including different laser spot sizes,wavelengths,plate's tilt angles,and plate-target spacing.The results reveal that the bombardment power density increases with a decrease in laser spot size and wavelength.For instance,when the plate is parallel to the target surface with a 1 mm spacing,the bombardment power density triples as the laser spot size decreases from 0.8 mm to 0.5 mm and quadruples as the wavelength decreases from 1064 nm to 266 nm.Notably,when the plate is parallel to the target with a relatively close spacing of 0.5 mm,the bombardment power density at 0°inclination increases sevenfold compared to 45°.This simulation study is essential for optimizing optical parameters and designing component layouts in decontamination devices using laser-induced plasma.The reduction of laser spot size,wavelength,plate-target spacing and aligning the plate parallel to the target,collectively contribute to achieving precise and effective decontamination.
文摘Objectives: The existing inflammatory models are concentrated in relatively complex medical fields, and most of them use a single type of cell, and the induction conditions are not uniform, so the current LPS-induced inflammation model is less conducive to the study of skin inflammation. The aim of this research is to enhance the existing LPS-induced inflammation model and establish a skin inflammation model that is suitable for the swift screening of anti-inflammatory agents in the cosmetics industry. Methods: LPS was used to induce inflammatory responses in KC and THP-1 cells. Enzyme-linked immunosorbent assay (ELISA) was employed to assess the levels of IL-1α, IL-8, and TNF-α in the two cell types, while the DCFH-DA probe was utilized to label the levels of reactive oxygen species (ROS) in both cell types. Results: In KC cells, 10 μg/mL of LPS induced a significant upregulation of IL-8 but did not result in elevated expression of IL-1α. However, at 100 μg/mL of LPS, both IL-8 and IL-1α were highly expressed in KC cells. LPS concentrations ranging from 0.01 to 100 μg/mL failed to stimulate TNF-α production in KC cells but induced a gradient increase in ROS levels. In THP-1 cells, LPS concentrations from 0.01 to 100 μg/mL did not induce IL-1α production but significantly elevated IL-8 and led to a gradient increase in TNF-α and ROS. After treatment with 100 μg/mL of LPS, the cosmetic ingredient Rucika KGM mitigated the elevated levels of IL-1α, IL-8, and ROS in LPS-induced KC cells and IL-8 and ROS in THP-1 cells. Conclusion: This study has successfully developed an application-oriented model suitable for investigating skin inflammation, enabling the rapid and comprehensive screening of cosmetic ingredients with anti-inflammatory activity. .
文摘Cord fabric is a critical material used in the manufacture of tyres and various composite materials to increase durability and strength. The tyre consists of many layers of cord fabric, with each layer being referred to as a cord ply. These layers are strategically positioned within the tyre’s internal structure, particularly in the tread and sidewall areas, to improve handling, durability and impact resistance. The cord fabric also serves a critical role in maintaining the structural integrity of the tyre, ensuring that it retains its contour and resists deformations under different operating conditions. This study discusses the advantages and disadvantages of using Nylon 6 (NY6) and Nylon 66 (NY66) cord fabrics in scooter tire production, with a focus on their mechanical behavior under varying curing temperatures and pressures. It was observed that while the curing time for both NY6 and NY66 remained consistent across different platen temperatures and pressures, their mechanical properties showed significant differences. NY6, known for its flexibility and impact resistance, exhibited greater changes in cord-breaking strength and elongation with increasing temperature, showing a marked decrease in breaking strength at higher temperatures. In contrast, NY66 maintained better stability and performance under similar conditions.
文摘Antiozonants and antioxidants are additives commonly used in the rubber industry to enhance the durability and performance of rubber products. Ozone, present in the atmosphere, can cause rubber to degrade over time through a process known as ozone cracking. These rubber additives are added to rubber compounds to protect against this degradation. They work by reacting with ozone, preventing it from attacking and breaking the molecular chains in the rubber, helping to maintain the structural integrity of the rubber product. It is now well known that 6PPD contributes to the extension of the service life of rubber products. However, recent studies have shown that 6PPD can be harmful to the environment, especially when end-of-life tyres (ELTs) are contaminated with the water. With the effect of ozone, 6PPD is converted to 6PPD quinone, which is toxic enough to kill some sensitive fish species such as Coho Salmon (Oncorhynchus kisutch). This study drew attention to new chemical compounds and natural products that can be used as antiozonants and antioxidants in the rubber industry instead of 6PPD. Although the scientific studies are promising, the fact that 6PPD is still used in production shows that more scientific studies and social awareness need to be developed in this area.
