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Insight-HXMT observations of Swift J0243.6+6124: the evolution of RMS pulse fractions at super-Eddington luminosity 期刊论文 OAI收割
Monthly Notices of the Royal Astronomical Society, 2020, 卷号: 497, 页码: 5498-5506
作者: HXMT

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stars: neutron pulsars: individual: Swift J0243.6+6124 X-rays: binaries Astrophysics - High Energy Astrophysical Phenomena Abstract: Based on Insight-HXMT data, we report on the pulse fraction evolution during the 2017-2018 outburst of the newly discovered first Galactic ultraluminous X-ray (ULX) source Swift J0243.6+6124. The pulse fractions of 19 observation pairs selected in the rising and fading phases with similar luminosity are investigated. The results show a general trend of the pulse fraction increasing with luminosity and energy at supercritical luminosity. However, the relative strength of the pulsation between each pair evolves strongly with luminosity. The pulse fraction in the rising phase is larger at luminosity below 7.71 × 10³⁸ erg s^-1, but smaller at above. A transition luminosity is found to be energy independent. Such a phenomenon is first confirmed by Insight-HXMT observations and we speculate that it may have relation with the radiation-pressure-dominated accretion disc.

黄海桑沟湾水体及沉积物中微塑料污染特征研究 期刊论文 OAI收割
海洋环境科学, 2019, 卷号: 38, 期号: 2, 页码: 198-204
作者: 熊宽旭; 赵新月; 周倩; 付传城; 涂晨

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桑沟湾微塑料潮滩丰度空间分布 Sanggou bay microplastics tidal flats abundance spatial distribution In recent years,research on microplastics pollution in the marine environment has been increasing,but studies on microplastics in water bodies and sediments of the bay under the influence of high-intensity human activities are still rarely reported. In this study,the pollution characteristics of microplastics in the wayer and sediments of Sanggou bay were investigated in December 2017,after the harvest of large-scale aquaculture,with the aim to study the effects of aquaculture activities and hydrodynamics on pollution characteristics and spatial distribution of microplastics in the bay. The results showed that the types of microplastics in the water and sediments of Sanggou bay were mainly fibers,fragments,films,foams and particles. The microplastic abundances in the water and sediments were 1.8 ~ 31.2 N/L,31.2 ~ 1246.8 N/kg,respectively. The average particle sizes of microplastics in water and sediments were 0.51 0.20 mm and 1.54 1.02 mm,respectively. The results of spatial distribution of microplastics in Sanggou bay showed that the high abundance area mainly appears in the inshore waters,and the abundance of microplastics tends to decrease from the inner areas of estuary to the outshore areas. The heterogeneity of microplastic abundance and spatial distribution in Sanggou bay is mainly affected by human activities such as aquaculture,living and shipping,as well as hydrodynamics. In the future,fine sampling and analysis are needed to fully understand the temporal and spatial distribution of microplastics pollution in the bay areas.

食用蔬菜能吸收和积累微塑料 期刊论文 OAI收割
科学通报, 2019, 卷号: 64, 期号: 9, 页码: 928-934
作者: 李连祯; 周倩; 尹娜; 涂晨; 骆永明

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微塑料生菜聚苯乙烯微球吸收积累健康风险 microplastics lettuce polystyrene microbeads uptake accumulation human health risk Microplastic (MP, 100 nm-5 mm) may present an attributable risk to ecosystem and human health, and its pollution has become a global environmental concern. Despite a wealth of information on the accumulation of MPs in aquatic species, there is no information on the uptake and accumulation of MPs by higher plants. Terrestrial edible plants are directly exposed to MPs when agricultural soil was applied with organic manure, sewage sludge as fertilizer or plastic mulching. In this paper, the uptake of two sizes of polystyrene (PS) microbeads (0.2 and 1.0 mum) and then their distribution and migration in an edible plant lettuce were firstly investigated based on laboratory experiments. We used fluorescent markers to track PS microbeads in plant tissues and found fluorescence to be a sensitive and reliable detection method. Sections from untreated control lettuce showed no autofluorescence. When roots were treated with fluorescently labeled PS microbeads, the microbeads could be identified by its fluorescence. Our main study investigated the uptake of 0.2 mum beads, as few luminescence signals were observed in lettuce roots for 1.0 mum beads in our experiment. We observed that 0.2 mum fluorescent microbeads were extracellularly trapped in the root cap mucilage (which is a highly hydrated polysaccharide) and a dark green tip (which was typical of lettuce roots exposed to label PS beads) was usually visible to the naked eye. Confocal images revealed that the PS luminescence signals were mainly located in the vascular system and on the cell walls of the cortex tissue of the roots, indicated that the beads passed through the intercellular space via the apoplastic transport system. Once inside the central cylinder, the 0.2 mum PS beads were transferred from the roots to the stems and leaves via the vascular system following the transpiration stream. We also observed that the PS beads adhered to one another and self-assembled systematically into grape-like and (chain) string-like clusters in the intercellular space of the root and stem vascular tissue of lettuce plant. In contrast to the root and stem, PS beads were dispersed in the leaf tissue. Here, for the first time we provide evidence of the adherence, uptake, accumulation, and translocation of submicrometer MPs within an edible plant. Our findings highlight the previously underappreciated human exposure pathway to MPs through the consumption of contaminated crops and emphasize the need for new management strategies to control the release of MPs waste products into the terrestrial environment. Ultimately, the potential impacts of low range sized MPs on food safety of crop plants and human health need to be urgently considered.

烟台夹河口外柱状沉积物还原性无机硫、活性铁的变化特征及其相互关系 期刊论文 OAI收割
海洋科学, 2018, 卷号: 42, 期号: 8, 页码: 90-97
作者: 姜明; 赵国强; 李兆冉; 盛彦清

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还原性无机硫活性铁深层柱状沉积物硫化度矿化度 Reduced inorganic sulfur Reactive iron Deep core sediments Degree of pyritization Degree of sulfidity The distribution characteristics and coupling mechanism of reduced inorganic sulfur (RIS)and reactive iron in marine core sediments are closely related to the evolution of environment quality.In this study,an improved cold diffusion method and hydrochloric acid extraction method were applied to the acid-volatile sulfur (AVS),pyrite sulfur (CRS),elemental sulfur (ES),and reactive iron [Fe (Ⅱ)and Fe (III)] analyses.The distribution characteristics and coupling mechanism of S and Fe were investigated based on a core sediment 4 meters deep collected in the northern sea area of the mouth of Jiahe River,Yantai.The results showed that the RIS in sediments was dominated by CRS,followed by AVS and ES.The content of AVS presented a narrow range with depth,whereas the CRS and ES were higher at the top and bottom layers than the middle layer reactive iron was dominated by Fe (II),which increased with depth,while Fe (Ⅲ)gradually decreased with depth.Most of the Fe (III)was reduced to the disssolved Fe(II),which was combined with the soluble H_2S of the sulfate-reducing bacteria to produce CRS and ES in the deep layer,resulting in their accumulation at the bottom of core sediments.Furthermore,this study showed that reactive iron was not a limiting factor for the accumulation of RIS with lower degree of pyritization and degree of sulfidity.

Correlations between neutrons and protons near the Fermi surface and Q(alpha) of superheavy nuclei 期刊论文 OAI收割
PHYSICAL REVIEW C, 2016, 卷号: 93, 期号: 1, 页码: 14302
作者: Wang, N; Liu, M; Wu, XZ; Meng, J; Wang, N (reprint author), Guangxi Normal Univ, Dept Phys, Guilin 541004, Peoples R China.

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The Shell Corrections And Shell Gaps In Nuclei Are Systematically Studied With The Latest Weizsacker-skyrme (Ws4) Mass Model. We Find That Most Of Asymmetric Nuclei With (Sub) Shell Closures Locate Along The Shell Stability Line (Ssl) n=1.37z+13.5 Which Might Be Due To a Strong Correlation Between Neutrons And proTons Near The Fermi Surface. The Double Magicity Of Nuclei Si-46 And Ni-78 Is Predicted According To The Corresponding Shell Gaps Shell Corrections And Nuclear Deformations. The Unmeasured Superheavy Nuclei (296)118 And (298)120 With Relatively Large Shell Gaps And Shell Corrections Also Locate Along The Ssl Whereas The Traditional Magic Nucleus (298)F1 Evidently Deviates From The Line. The Alpha-decay Energies Of Superheavy Nuclei With Z=113-126 Are Simultaneously Investigated By Using The Ws4 Model togeTher With The Radial Basis Function Corrections. For Superheavy Nuclei With Large Shell Corrections The Smallest Alpha-decay Energy For Elements Z=116 117 And 118 In Their Isotope chaIns LocAtes At N=178 rAther Than 184.

Gradient Structure-Induced Temperature Responsiveness in Styrene/Methyl Methacrylate Gradient Copolymers Micelles 期刊论文 OAI收割
macromolecular rapid communications, 2014, 卷号: 35, 期号: 3, 页码: 309-316
Zheng,Chao; Huang,Haiying; He,Tianbai

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In this work micelles are formed by gradient copolymer of styrene and methyl methacrylate in acetone-water mixture and their temperature responsiveness is investigated in a narrow range near room temperature. Three different kinds of structural transitions could be induced by temperature: unimers to micelle transition shrinkage/stretching of micelles and morphological transition from spherical micelles to vesicles. In addition a model analysis on the interface of gradient copolymer micelle is made to better understand these phenomena. It is found that both position and composition of the interface could alter in response to the change in temperature. According to the experiments and model analysis it is proposed that temperature responsiveness might be an intrinsic and universal property of gradient copolymer micelles which only originates from the gradient structure.

Silica nanospheres for filtering higher-order optical fiber modes (EI CONFERENCE) 会议论文 OAI收割
作者: Hao P.; Li K.; Liu G.

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Tapered optical fibers (TOFs) modified by 400 nm-diameter silica nanospheres have been experimentally and theoretically investigated. Responses of the modified TOFs (MTOFs) to methylene blue (MB) solution and surrounding refractive index (RI) have been compared. The higher-order modes are effectively filtered by the silica nanospheres which is visualized by the interferometric output spectrum of the MTOF. The higher-order mode filtering makes the MTOF respond to MB solution with reduced sensitivity which endows the MTOF with the potential for distinguishing the RI property from the absorption property of the molecules under detection. 2013 Optical Society of America.

Structure and magnetic properties of (Al, Co) Co-doped ZnO thin films (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Materials Science and Nanotechnology, ICMSN 2012, November 16, 2012 - November 18, 2012, Guangzhou, China
Cao P.; Bai Y.

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In this study Zn0.99Co0.01Al0.015O thin film has been prepared by sol-gel method. The structural and magnetic properties of the sample were investigated. X-ray diffraction spectroscopy analyses indicate that the Co and Al codoping can not disturb the structure of ZnO. No additional peaks are observed in the Zn0.99Co0.01Al xO and Al3+ and Co2+ substitute for Zn 2+ without changing the wurtzite structure. The resistance measurements confirm that Al ions increase the free carriers concentration. Based on the above experiments we think the ferromagnetic behavior of the sample could not originate from Co nanoclusters. The presence of free carriers and localized d spins is a prerequisite for the appearance of ferromagnetism. As the result the carriers generated by Al doping is considered a main factor to induce the ferromagnetic phenomenon. (2013) Trans Tech Publications Switzerland.

Tribological properties of Mos2 thin coatings under liquid lubricating (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Innovation Manufacturing and Engineering Management, IMEM 2012, December 14, 2012 - December 16, 2012, Chongqing, China
Bai Y.; Cao P.

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The objective of this study is to investigate the effect of solid and liquid lubrication on friction and wear performance of selected solid lubricating coatings comparative experiments have been carried out on magnetron sputtered MoS2 coatings against Si3N4 ball using a ball-on-disk tribo-tester under the conditions of room temperature and different lubrication. Surface morphology of coatings were investigated by atom force microscope (AFM) and friction coefficient (COF) and wear rate of solid films were also be analyzed. It was shown that the friction is greatly reduced when the solid film is lubricated with oil and grease simultaneously in comparison with single-lubricant lubrication at the start-up or under boundary lubrication conditions. Liquid lubrication causes a dramatic decrease of the wear-ability of the MoS2 coatings. The effect of oil lubrication to the deterioration of wear resistance of MoS2 film was even worse than lubrication grease. (2013) Trans Tech Publications Switzerland.

Laser cleaning of neutral attenuator plate based on low power laser diode (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Energy, Environment and Sustainable Development, EESD 2012, October 12, 2012 - October 14, 2012, Jilin, China
作者: Chen Y.; Li L.

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Laser cleaning is a non-contact green and environmental cleaning method which can effectively remove particulate contaminations of sizes as small as 0.1 m without damage to the optics. But most laser cleaning devices are large and heavy also expensive due to using large lasers such as CO2 laser YAG Laser etc. In this work a low power LD was tried to clean fingerprint and dust contaminated on the surface of the attenuator glasses plates. In the laser cleaning experiment with low power diode the fingerprint grease can be efficient to be cleaned but there is no evident effect for cleaning inorganic dust. The cleaning different degree of fingerprint contaminations was investigated at the variable laser parameters including laser power and irradiation time. An optical microscope was used to analyze the cleaning effect. The results show that low power LD can effectively remove the fingerprint on the surface of absorptive-type attenuator glass plates. On the premise that the attenuator optics glasses are not damaged the cleaning area increases with the increase of radiation time and laser power. The cleaning area doesn't change much with the variation of laser frequency when the other parameters are the same. (2013) Trans Tech Publications Switzerland.