Wildfire smoke plays a crucial role in climate change,air quality,human health,and the ecosystem.With the warming and drying of the climate,the scope,frequency,and intensity of global wildfire events are increasing ra...Wildfire smoke plays a crucial role in climate change,air quality,human health,and the ecosystem.With the warming and drying of the climate,the scope,frequency,and intensity of global wildfire events are increasing rapidly[1,2].Southeast Asia,South America,Africa,and Australia are the major regions in which wildfires occur[3,4];Southeast Asia is the hotspot of wildfires and neighbors the South China Sea(SCS)[5].Therefore,the air quality and climate in the SCS can be affected by the transport of wildfire smoke in Southeast Asia.Many studies have focused on the transport pathways from Southeast Asia to the SCS,especially studies based on BASE-ASIA(Biomass-burning Aerosols in South-East Asia)and 7-SEAS(7-South-East Asian Studies)experiments[5,6].展开更多
Isolated attosecond pulses(IAPs)are generated via applying amplitude gating on high-order harmonic generation driven by carrier-envelope phase stabilized 5.2 fs pulses with 0.5 mJ pulse energy at 770 nm central wavele...Isolated attosecond pulses(IAPs)are generated via applying amplitude gating on high-order harmonic generation driven by carrier-envelope phase stabilized 5.2 fs pulses with 0.5 mJ pulse energy at 770 nm central wavelength at the Synergetic Extreme Condition User Facility.A continuum ranging from 70 to 100 eV that supports sub-100-attosecond pulse is extracted by Zr foil and Mo/Si multilayer mirror.We demonstrate the characterization of the IAP.The retrieved pulse duration is 86attoseconds.The developed attosecond laser beamline with repetition rate up to 10 kHz is available for users to conduct attosecond photoelectron spectroscopy researches with a capability of coincidence measurement.展开更多
A novel image encryption scheme based on parallel compressive sensing and edge detection embedding technology is proposed to improve visual security. Firstly, the plain image is sparsely represented using the discrete...A novel image encryption scheme based on parallel compressive sensing and edge detection embedding technology is proposed to improve visual security. Firstly, the plain image is sparsely represented using the discrete wavelet transform.Then, the coefficient matrix is scrambled and compressed to obtain a size-reduced image using the Fisher–Yates shuffle and parallel compressive sensing. Subsequently, to increase the security of the proposed algorithm, the compressed image is re-encrypted through permutation and diffusion to obtain a noise-like secret image. Finally, an adaptive embedding method based on edge detection for different carrier images is proposed to generate a visually meaningful cipher image. To improve the plaintext sensitivity of the algorithm, the counter mode is combined with the hash function to generate keys for chaotic systems. Additionally, an effective permutation method is designed to scramble the pixels of the compressed image in the re-encryption stage. The simulation results and analyses demonstrate that the proposed algorithm performs well in terms of visual security and decryption quality.展开更多
Conventional gradient-based full waveform inversion (FWI) is a local optimization, which is highly dependent on the initial model and prone to trapping in local minima. Globally optimal FWI that can overcome this limi...Conventional gradient-based full waveform inversion (FWI) is a local optimization, which is highly dependent on the initial model and prone to trapping in local minima. Globally optimal FWI that can overcome this limitation is particularly attractive, but is currently limited by the huge amount of calculation. In this paper, we propose a globally optimal FWI framework based on GPU parallel computing, which greatly improves the efficiency, and is expected to make globally optimal FWI more widely used. In this framework, we simplify and recombine the model parameters, and optimize the model iteratively. Each iteration contains hundreds of individuals, each individual is independent of the other, and each individual contains forward modeling and cost function calculation. The framework is suitable for a variety of globally optimal algorithms, and we test the framework with particle swarm optimization algorithm for example. Both the synthetic and field examples achieve good results, indicating the effectiveness of the framework. .展开更多
The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco...The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco-planting soils are still lacking systematic research. In this study, three different tillage depths of 15 cm (T1), 20 cm (T2), and 30 cm (T3) were set up for field experiments in Liupanshui, Guizhou Province, to explore the effects of tillage depth on tobacco-planting soil nutrients and bacterial and fungal communities based on 16S rRNA and ITS sequencing and figure out the key factors affecting soil microbial communities. The results showed that T2 and T3 increased the contents of organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium in tobacco-planting soil, and increased the diversity of bacterial communities compared with T1. There was no significant difference in the structure of bacterial and fungal communities in different tillage depth treatments, but some dominant genera were significantly enriched in T2 and T3. Desulfobacter, Setophoma, Humicola, and Acremonium were significantly enriched in T2. Chthonomonas and Fusarium were significantly enriched in T3. These genera favor the decomposition of organic matter and the cycling of nutrients, and control soil pests and diseases. Redundancy analysis indicated that TP and AK were the key factors influencing the dominant genera of bacteria and fungi. This study provides a scientific basis for the selection of soil tillage depth for tobacco production in this region.展开更多
建立一种采用分散液液微萃取-高效液相色谱法(dispersive liquid-liquid microextraction coupled with high performance liquid chromatography,DLLME-HPLC)联用对豆浆中的双酚A进行萃取和检测的新方法,并考察不同因素对萃取回收率和...建立一种采用分散液液微萃取-高效液相色谱法(dispersive liquid-liquid microextraction coupled with high performance liquid chromatography,DLLME-HPLC)联用对豆浆中的双酚A进行萃取和检测的新方法,并考察不同因素对萃取回收率和富集倍数的影响.实验结果表明,在最优化的萃取条件下,在1～100μg/L质量浓度范围内,双酚A的质量浓度与色谱峰面积呈良好的线性关系,检出限为0.3μg/L,加标回收率在91.6%～97.5%之间,相对标准偏差小于6%.这说明该方法的准确度和重现性较好,具有可行性,适用于对市售豆浆饮品中双酚A质量含量的测定.展开更多
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)the National Key Research and Development Program of China(2023YFC3709201,2023YFC3706103,2023YFC3710900)+4 种基金the National Natural Science Foundation of China(42175111)the Fundamental Research Funds for the Central UniversitiesSun Yat-sen University(23lgbj002)the specific research fund of The Innovation Platform for Academicians of Hainan Province(YSPTZX202143)the Guangdong Science and Technology Plan Project(2019B121201002)。
文摘Wildfire smoke plays a crucial role in climate change,air quality,human health,and the ecosystem.With the warming and drying of the climate,the scope,frequency,and intensity of global wildfire events are increasing rapidly[1,2].Southeast Asia,South America,Africa,and Australia are the major regions in which wildfires occur[3,4];Southeast Asia is the hotspot of wildfires and neighbors the South China Sea(SCS)[5].Therefore,the air quality and climate in the SCS can be affected by the transport of wildfire smoke in Southeast Asia.Many studies have focused on the transport pathways from Southeast Asia to the SCS,especially studies based on BASE-ASIA(Biomass-burning Aerosols in South-East Asia)and 7-SEAS(7-South-East Asian Studies)experiments[5,6].
基金supported by the Synergic Extreme Condition User Facility(SECUF),the National Natural Science Foundation of China(Nos.91850209,12034020,92150103,61690221,and 12174435)the National Key R&D Program of China(Nos.2022YFA1604200 and 2017YFB0405202)。
文摘Isolated attosecond pulses(IAPs)are generated via applying amplitude gating on high-order harmonic generation driven by carrier-envelope phase stabilized 5.2 fs pulses with 0.5 mJ pulse energy at 770 nm central wavelength at the Synergetic Extreme Condition User Facility.A continuum ranging from 70 to 100 eV that supports sub-100-attosecond pulse is extracted by Zr foil and Mo/Si multilayer mirror.We demonstrate the characterization of the IAP.The retrieved pulse duration is 86attoseconds.The developed attosecond laser beamline with repetition rate up to 10 kHz is available for users to conduct attosecond photoelectron spectroscopy researches with a capability of coincidence measurement.
基金supported by the Key Area R&D Program of Guangdong Province (Grant No.2022B0701180001)the National Natural Science Foundation of China (Grant No.61801127)+1 种基金the Science Technology Planning Project of Guangdong Province,China (Grant Nos.2019B010140002 and 2020B111110002)the Guangdong-Hong Kong-Macao Joint Innovation Field Project (Grant No.2021A0505080006)。
文摘A novel image encryption scheme based on parallel compressive sensing and edge detection embedding technology is proposed to improve visual security. Firstly, the plain image is sparsely represented using the discrete wavelet transform.Then, the coefficient matrix is scrambled and compressed to obtain a size-reduced image using the Fisher–Yates shuffle and parallel compressive sensing. Subsequently, to increase the security of the proposed algorithm, the compressed image is re-encrypted through permutation and diffusion to obtain a noise-like secret image. Finally, an adaptive embedding method based on edge detection for different carrier images is proposed to generate a visually meaningful cipher image. To improve the plaintext sensitivity of the algorithm, the counter mode is combined with the hash function to generate keys for chaotic systems. Additionally, an effective permutation method is designed to scramble the pixels of the compressed image in the re-encryption stage. The simulation results and analyses demonstrate that the proposed algorithm performs well in terms of visual security and decryption quality.
文摘Conventional gradient-based full waveform inversion (FWI) is a local optimization, which is highly dependent on the initial model and prone to trapping in local minima. Globally optimal FWI that can overcome this limitation is particularly attractive, but is currently limited by the huge amount of calculation. In this paper, we propose a globally optimal FWI framework based on GPU parallel computing, which greatly improves the efficiency, and is expected to make globally optimal FWI more widely used. In this framework, we simplify and recombine the model parameters, and optimize the model iteratively. Each iteration contains hundreds of individuals, each individual is independent of the other, and each individual contains forward modeling and cost function calculation. The framework is suitable for a variety of globally optimal algorithms, and we test the framework with particle swarm optimization algorithm for example. Both the synthetic and field examples achieve good results, indicating the effectiveness of the framework. .
文摘The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco-planting soils are still lacking systematic research. In this study, three different tillage depths of 15 cm (T1), 20 cm (T2), and 30 cm (T3) were set up for field experiments in Liupanshui, Guizhou Province, to explore the effects of tillage depth on tobacco-planting soil nutrients and bacterial and fungal communities based on 16S rRNA and ITS sequencing and figure out the key factors affecting soil microbial communities. The results showed that T2 and T3 increased the contents of organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium in tobacco-planting soil, and increased the diversity of bacterial communities compared with T1. There was no significant difference in the structure of bacterial and fungal communities in different tillage depth treatments, but some dominant genera were significantly enriched in T2 and T3. Desulfobacter, Setophoma, Humicola, and Acremonium were significantly enriched in T2. Chthonomonas and Fusarium were significantly enriched in T3. These genera favor the decomposition of organic matter and the cycling of nutrients, and control soil pests and diseases. Redundancy analysis indicated that TP and AK were the key factors influencing the dominant genera of bacteria and fungi. This study provides a scientific basis for the selection of soil tillage depth for tobacco production in this region.
文摘建立一种采用分散液液微萃取-高效液相色谱法(dispersive liquid-liquid microextraction coupled with high performance liquid chromatography,DLLME-HPLC)联用对豆浆中的双酚A进行萃取和检测的新方法,并考察不同因素对萃取回收率和富集倍数的影响.实验结果表明,在最优化的萃取条件下,在1～100μg/L质量浓度范围内,双酚A的质量浓度与色谱峰面积呈良好的线性关系,检出限为0.3μg/L,加标回收率在91.6%～97.5%之间,相对标准偏差小于6%.这说明该方法的准确度和重现性较好,具有可行性,适用于对市售豆浆饮品中双酚A质量含量的测定.
