In a recent paper, solution-state ^(19)F NMR spectroscopy was used to probe the conformational dynamics of β-arrestin-1, an essential adaptor and signaling component of the G-protein couple receptor (GPCR) signaling ...In a recent paper, solution-state ^(19)F NMR spectroscopy was used to probe the conformational dynamics of β-arrestin-1, an essential adaptor and signaling component of the G-protein couple receptor (GPCR) signaling pathway. This work reveals a highly complex conformational energy landscape of β-arrestin-1, and illuminates the molecular mechanism of the membrane phosphoinositide PIP2-induced β-arrestin-1 activation at residue level.(https://doi.org/10.1038/s41467-023-43694-1).展开更多
Fluorine owing to its inherently high electronegativity exhibits charge delocalization and ion dissociation capabilities;as a result,there has been an influx of research studies focused on the utilization of fluorides...Fluorine owing to its inherently high electronegativity exhibits charge delocalization and ion dissociation capabilities;as a result,there has been an influx of research studies focused on the utilization of fluorides to optimize solid electrolyte interfaces and provide dynamic protection of electrodes to regulate the reaction and function performance of batteries.Nonetheless,the shuttle effect and the sluggish redox reaction kinetics emphasize the potential bottlenecks of lithium-sulfur batteries.Whether fluorine modulation regulate the reaction process of Li-S chemistry?Here,the TiOF/Ti_(3)C_(2)MXene nanoribbons with a tailored F distribution were constructed via an NH4F fluorinated method.Relying on in situ characterizations and electrochemical analysis,the F activates the catalysis function of Ti metal atoms in the consecutive redox reaction.The positive charge of Ti metal sites is increased due to the formation of O-Ti-F bonds based on the Lewis acid-base mechanism,which contributes to the adsorption of polysulfides,provides more nucleation sites and promotes the cleavage of S-S bonds.This facilitates the deposition of Li_(2)S at lower overpotentials.Additionally,fluorine has the capacity to capture electrons originating from Li_(2)S dissolution due to charge compensation mechanisms.The fluorine modulation strategy holds the promise of guiding the construction of fluorine-based catalysts and facilitating the seamless integration of multiple consecutive heterogeneous catalytic processes.展开更多
With the popularity and widespread applications of electronics,higher demands are being placed on the performance of battery materials.Due to the large difference in electronegativity between fluorine and carbon atoms...With the popularity and widespread applications of electronics,higher demands are being placed on the performance of battery materials.Due to the large difference in electronegativity between fluorine and carbon atoms,doping fluorine atoms in nanocarbon-based materials is considered an effective way to improve the performance of used battery.However,there is still a blank in the systematic review of the mechanism and research progress of fluorine-doped nanostructured carbon materials in various batteries.In this review,the synthetic routes of fluorinated/fluorine-doped nanocarbon-based(CF_x)materials under different fluorine sources and the function mechanism of CF_x in various batteries are reviewed in detail.Subsequently,judging from the dependence between the structure and electrochemical performance of nanocarbon sources,the progress of CF_x based on different dimensions(0D–3D)for primary battery applications is reviewed and the balance between energy density and power density is critically discussed.In addition,the roles of CF_x materials in secondary batteries and their current applications in recent years are summarized in detail to illustrate the effect of introducing F atoms.Finally,we envisage the prospect of CF_x materials and offer some insights and recommendations to facilitate the further exploration of CF_x materials for various high-performance battery applications.展开更多
In order to find out the effects of soil fluorine on ecological environment and crop safety in the sorghum cultivation base of Renhuai City, Guizhou Province, the content and the occurrence forms of soil fluorine and ...In order to find out the effects of soil fluorine on ecological environment and crop safety in the sorghum cultivation base of Renhuai City, Guizhou Province, the content and the occurrence forms of soil fluorine and its influencing factors of Maoba Town were investigated and studied. The results showed that the total fluorine content in the soil of the sorghum base ranged from 668.60 to 2 596.80 mg/kg, with an average of 1 483.25 mg/kg, which was 3.10 and 1.85 times of the national soil background value and the average value of the soil in endemic areas, respectively. The spatial distribution of fluorine in the soil of the study area was uneven, and the fluorine content was in the order of Anliang Village>Yangliu Village>Houba Village>Xiongfeng Village. The soil fluorine contents of various forms varied greatly, and the distribution law was as follows: residual state>water soluble state>organically bound state>exchangeable state>Fe/Mn-F state. The residual fluorine content was the highest, accounting for more than 99% of total fluorine content, while the sum of other four forms was less than 1%, with their respective proportions ranging from 0.10% to 0.30%. The content and proportion of available fluorine in water-soluble and exchangeable states were relatively low, which had limited influence on the surrounding water environment and crop safety. The physicochemical properties of soil, such as pH, organic matter, cation exchange capacity and clay particles had a certain influence on the occurrence forms of soil fluorine, thus changing the availability and migration of soil fluorine, which might endanger the ecological environment safety, food safety and human health.展开更多
The high concentration electrolytes with specific solvation structure could passivate the electrodes to prolong battery cycle life but at the expense of increased cost,which limits the wide application in commercializ...The high concentration electrolytes with specific solvation structure could passivate the electrodes to prolong battery cycle life but at the expense of increased cost,which limits the wide application in commercialization.The regular concentration(1_(M))electrolytes with suitable properties(viscosity,ionic conductivity,etc.)are cost-guaranteed,but undesired reactions would always occur and lead to battery degradation during long cycles.To promote the long-term cycle stability in a cost-effective way,this work constructs bidirectional fluorine-rich electrode/electrolyte interphase(EEI)by redistribution of solvents and electrochemical induction.The fluorinated effect with reasonable zoning planning restricts morphological disintegration,meanwhile,forms spatial confinement on cathode.In particular,the obtained cathode electrolyte interphase(CEI)gets the ample ability of Na^(+)transport,which benefits from the fluorinated organics arranged in the epitaxy and the hemi-carbonate content acting on the thickness.Thus,the electrochemical long cycling performance of F-NVPOFⅡF-CC full cells is significantly enhanced(the decay rate at 1 C per cycle is as low as 0.01%).Such a fluorine-rich EEI engineering is expected to take transitional layers against the degradation of cells and make ultra-long cycle batteries possible.展开更多
The firing tests with clay blocks were undertaken to study thefluorine expulsion and retention char- acteristics of calcium-basedmaterials during the firing of brick clays. The results indicate thatfluorine expulsion ...The firing tests with clay blocks were undertaken to study thefluorine expulsion and retention char- acteristics of calcium-basedmaterials during the firing of brick clays. The results indicate thatfluorine expulsion begins at approx. 600-700 deg. C, and the mainportion occurs in 800-1000 deg. C. The mode of firing has someeffects on fluorine expulsion. Additives of calcium-based materialcan reduce fluorine expulsion, which is mainly attributed to theincreased formation of CaF_2 during clay firing. In addition, theoptimum addition tests of 6 calcium-based materials with higherefficiency were carried out in a brick kiln. More than 75/100fluorine is retained in the brick body and there is no adverse effecton brick product. This makes it possible for brickyard to achievenon-polluting production.展开更多
Tongshan area,a part of the floodplain of the abandoned Huanghe River, is one of the popular endemic fluorosis areas in East China. One of the reasons is high concentration of fluorine in shallow groundwater. Test res...Tongshan area,a part of the floodplain of the abandoned Huanghe River, is one of the popular endemic fluorosis areas in East China. One of the reasons is high concentration of fluorine in shallow groundwater. Test results of 36 groundwater samples show that fluorine concentration in shallow groundwater is 0.18–6.7 mg/L and 50 % of the samples exceed the Chinese drinking water quality standard. There exists a significant negative correlation in content between Ca2+ and F - . The correlations between fluorine concentration and other cations (for example Na+, K+, Mg2+) are not significant. The content of dissolved fluorine from the flooding sediments of the Huanghe River that varying from 5.6 mg/kg to 15.2 mg/kg plays an important role in forming the high fluorine groundwater. Usually, the dissolved fluorine content in silt is much higher than that in silty clay and clay. According to the geological investigation fluorine content in deep groundwater (over 60 m) is less than 1.0 mg/L and suitable for drinking, so it is an effective measure to prevent endemic fluorosis by extracting deep groundwater in disease areas.展开更多
A detailed comparison was done between the data about the F in coals published at home and abroad, and associated with the special situation in China. An introduction also was made to illuminate the forming, occurrenc...A detailed comparison was done between the data about the F in coals published at home and abroad, and associated with the special situation in China. An introduction also was made to illuminate the forming, occurrence and accumulation of the F in coals and its potential hazard to human and environment. Analytical data of coal samples were referred to study the great difference of the F content between coals and gangue. The results show that the average value of the F in the coal samples collected in different coalfields of China is 304x10^6, while that of gangue samples is surprisingly 1 319x10^6, especially the F content of coal ash from Bangmai in Yunnan Province reaches 4 800x10^6. It has been proved in many provinces of China that burning the coal and clay mixture can produce F contamination.展开更多
In order to determine the mechanism of bacterial tolerance to fluorine,Acidithiobacillus ferrooxidans ATCC 23270 was domesticated and studied under the conditions of different fluorine concentrations and pH values wit...In order to determine the mechanism of bacterial tolerance to fluorine,Acidithiobacillus ferrooxidans ATCC 23270 was domesticated and studied under the conditions of different fluorine concentrations and pH values with or without treatment by Proteinase K.The bacterial activities were observed through measuring the changes of solution potentials by platinum electrode with Ag/AgCl reference electrode and the intracellular fluorine was determined by-uorine ion-selective electrode.The results indicated that the tolerance of Acidithiobacillus ferrooxidans ATCC 23270 to fluorine could be obviously improved by domestication,HF was the effective form of fluorine to affect the bacterial activity,and pH increase or concentration change of ions of strong complex ability with fluorine ions in solution could result in false appearance of high fluorine-resistant strain.Some proteins located in cell wall or cell membrane were intimately relative with the bacterial fluorine tolerance.展开更多
The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the abso...The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the absorption edge of TiO 2 to shift to a lower energy region. The photocatalytic activity of co doped TiO 2 with anatase phases was found to be 2 4 times higher than that of the commercial TiO 2 photocatalyst Degussa P25 for phenol decomposition under visible light irradiation. The co doped TiO 2 powders only contain anatase phases even at 1000℃. Apparently, ammonium fluoride added retarded phase transformation of the TiO 2 powders from anatase to rutile. The substitutional fluorine and interstitial nitrogen atoms in co doped TiO 2 polycrystalline powder were responsible for the vis light response and caused the absorption edge of TiO 2 to shift to a lower energy region.展开更多
Siliconated polyurethane （Si-PU） was synthesized using isophorone diisocyanate （IPDI）, hydroxybutyl-terminated polydimethylsiloxane （PDMS）, polytetramethylene ether glycol （PTMG）, polypropylene glycol （PPG）,...Siliconated polyurethane （Si-PU） was synthesized using isophorone diisocyanate （IPDI）, hydroxybutyl-terminated polydimethylsiloxane （PDMS）, polytetramethylene ether glycol （PTMG）, polypropylene glycol （PPG）, 1,6-hexanediol （HDO）, dimethylol propionic acid （DMPA） and triethylamine （TEA）. Based on butyl acrylate （BA）, 2, 2, 2-trifluoroethylmethacrylate （TFEMA） and Si-PU as a seed emulsion, a novel core-shell type acrylic-polyurethane hybrid emulsion, containing siloxane and fluorine （F-Si-PU）, was prepared by seeded emulsion polymerization. The contents of siloxane and fluorine were determined according to the feed ratio. Fourier transform infrared spectroscopy （FTIR） was used to identify the chain structures of Si-PU and F-Si-PU. Investigation of transmission electron microscopy （TEM） confirmed the core-shell structure of F-Si-PU emulsion. Measurement results of water contact angle and the swelling ratio in water and n-octane for cured film showed that the water and the oil resistances for F-Si-PU had been significantly improved at a suitable content of fluorine and siloxane.展开更多
The different forms fluoine in different parts of molting process of krill was analyzed by culture of Antarctic krill (Euphausia superba). The results shaw that fluorine amount in cuticle is up to 90% of total in the ...The different forms fluoine in different parts of molting process of krill was analyzed by culture of Antarctic krill (Euphausia superba). The results shaw that fluorine amount in cuticle is up to 90% of total in the krill. During the krill molting process, the fluorine content in cuticle and muscle varies alternatively. This is to say, the fluorine content in new cuticle and muscle is much lower after molted, the fluorine in krill comes from seawater by biological absorption of the krill, and the fluorine absorbed by krill lost with the old cuticle at the end stage of molting process. Meanwhile, the new molting process starts again. The evidence is proved by the change of different forms fluorine content in cuticle and muscle during krill's molting process. At last the author proposes the fluorine enriching process model of Antarctic krill.展开更多
Ni-rich layered oxide LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(x≥0.8)is the most promising cathodes for future high energy automotive lithium-ion batteries.However,its application is hindered by the undesirable cycle stability,...Ni-rich layered oxide LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(x≥0.8)is the most promising cathodes for future high energy automotive lithium-ion batteries.However,its application is hindered by the undesirable cycle stability,mainly due to the irreversible structure change at high voltage.Herein,we demonstrate that F substitution with the appropriate amount(1 at%)is capable for improve the electrochemical performance of LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2) cathode significantly.It is revealed that F substitution can reduce cation mixing,stabilize the crystal structure and improve Li transport kinetics.The resulted LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(1.99)F_(0.01)cathode can deliver a high capacity of 194.4 mAh g^(-1) with capacity retention of 95.5%after 100 cycles at 2 C and 165.2 mAh g^(-1) at 5 C.In-situ synchrotron X-ray technique proves that F ions in the cathode materials can suppress the irreversible phase transition from H2 phase to H3 phase in high voltage region by preventing oxygen gliding in a-b planes,ensuring a long-term cycle stability.展开更多
Tailoring the microstructure of pristine TiO2 is essential to narrow its band gap and prolong the charge lifetime. In particular, strategies involving fluorine have been used successfully to tune the surface chemistry...Tailoring the microstructure of pristine TiO2 is essential to narrow its band gap and prolong the charge lifetime. In particular, strategies involving fluorine have been used successfully to tune the surface chemistry, electronic structure, and morphology of TiO2 photocatalysts to improve their photocatalytic activity based on the strong complexation between fluoride ions and TiO2 and the high electronegativity of fluorine. In this review, we summarize the strategies involving fluorine to establish highly efficient TiO2 photocatalytic systems or fabricate highly efficient TiO2 photocatalysts. The main fluorine effects(i.e. the effects of fluorine on photocatalysis) include the following four aspects:(1) Surface effects of fluoride on TiO2 photocatalysis,(2) effects of fluorine doping on TiO2 photocatalysis,(3) fluoride-mediated tailoring of the morphology of TiO2 photocatalysts, and(4) the effects of fluorine on non-TiO2 photocatalysis. Additionally, the unique applications of these fluorine effects in photocatalysis, including selective degradation of pollutants, selective oxidation of chemicals, water-splitting to produce H2, reduction of CO2 to produce solar fuels, and improvement of the thermostability of TiO2 photocatalysts, are reviewed.展开更多
A novel compound of 9-[3-oxo-1-（4-bromopheny）-3-phenypropyl]fluorine （3） was synthesized via nucleophilic addition reaction under solvent-free condition. Its structure was determined by IR, 1H NMR, MS, elemental a...A novel compound of 9-[3-oxo-1-（4-bromopheny）-3-phenypropyl]fluorine （3） was synthesized via nucleophilic addition reaction under solvent-free condition. Its structure was determined by IR, 1H NMR, MS, elemental analysis and X-ray diffraction. The crystal of the new compound is of triclinic system, space group P-1 with a=9.7919（16）, b=11.0932（18）, c=11.2534（19） , α=76.927（3）, β=67.452（3）, γ=84.895（3）°, V=1099.7（3） 3, Z=2, Dc=1.369 g/cm3, μ=1.886 mm-1, F（000）=464, R=0.0586 and wR=0.1562 for 3145 observed reflections with Ⅰ 2σ（Ⅰ）. π-π Stacking interactions contribute to the stability of the structure.展开更多
A new method for the simultaneous determination of fluorine and iodine in urine by ion chromatography （IC） with electrochemical pretreatment has been developed. The pretreatment was performed in a novel electrochemi...A new method for the simultaneous determination of fluorine and iodine in urine by ion chromatography （IC） with electrochemical pretreatment has been developed. The pretreatment was performed in a novel electrochemical oxidationneutralization device （EOND）, in which iodide of the sample was oxidized to iodate and the alkaline digestion sample solution was neutralized. Under the optimized conditions, the limits of detection （LOD, S/N = 3） were 2.5 μg/L for fluoride and 20 μg/L for iodate, respectively. The recoveries were in the range of 93-102% for fluoride and 86-98% for iodate.展开更多
With the aid of soil column test models,the transport rules of fluorine contaminants in unsaturated stratified soils are discussed. Curves of F-concentrations at different times and sites in the unsaturated stratified...With the aid of soil column test models,the transport rules of fluorine contaminants in unsaturated stratified soils are discussed. Curves of F-concentrations at different times and sites in the unsaturated stratified soil were ob-tained under conditions of continuous injection of fluoride contaminants and water. Based on the analysis of the actual observation data,the values between computed results and observed data were compared. It is shown that the chemical properties of fluorine ions are active. The migration process of fluorine ions in soils is complex. Because of the effect of adsorption and desorption,the curve of the fluorine ion breakthrough curve is not symmetric. Its concentration peak value at each measuring point gradually decays. The tail of the breakthrough curve is long and the process of leaching and purifying using water requires considerable time. Along with the release of OHˉ in the process of fluorine absorp-tion,the pH value of the soil solution changed from neutral to alkalinity during the test process. The first part of the breakthrough curve fitted better than the second part. The main reason is that fluorine does not always exist in the form of fluorinions in groundwater. Given the long test time,fluorinions possibly react with other ions in the soil solution to form complex water-soluble fluorine compounds. Only the retardation factor and source-sink term have been considered in our numerical model,which may leads to errors of computed values. But as a whole the migration rules of fluorine ions are basically correct,which indicates that the established numerical model can be used to simulate the transport rules of fluorine contaminants in unsaturated stratified soils.展开更多
Influence of CaO on thermal decomposition of REFCO3 was studied. The results showed that CaO did not affect significantly the decomposition ratio of REFCO3. The XRD experiment showed that there was a great deal of CaF...Influence of CaO on thermal decomposition of REFCO3 was studied. The results showed that CaO did not affect significantly the decomposition ratio of REFCO3. The XRD experiment showed that there was a great deal of CaF2 in the masting production, the gas chromatographic analysis on the gas of REFCO3 decomposed, and the 70% content of fluorine in the gas of REFCO3 added 15% CaO was reduced. CaO could absorb the fluorine from the decomposition of REFCO3, and the environmental pollution of the fluorine was greatly alleviated,展开更多
New fluorine substituted 6-(5’-fluoro-2’-triphenylphosphiniminophenyl) 3-thioxo-1,2,4-triazin-5 (2H, 4H) one (2) was obtained via Wittig’s reaction of the corresponding 6-(5’-fluoro-2’-amino-phenyl)-3-thioxo-1,2,...New fluorine substituted 6-(5’-fluoro-2’-triphenylphosphiniminophenyl) 3-thioxo-1,2,4-triazin-5 (2H, 4H) one (2) was obtained via Wittig’s reaction of the corresponding 6-(5’-fluoro-2’-amino-phenyl)-3-thioxo-1,2,4-triazinone (1). Behavior of compound 2 towards alkylating agents and/or oxidizing agents was studied were, N-hydroxyl (3), Mannich base (4,5), S-alkyl (6,7,8) and thiazolo [3,2-b][1,2,4] triazinones (10-14) and or 3-disulfide (18), 3-sulfonic acid 19 and 1,2,4-triazin-3,5-Dionne (20) derivatives obtained. Structures of the new products are established by elemental and spectral data. The new targets obtained screened as Molluscicidalagents against Biomophlaria Alexandrina snails responsible for Bilharziasis diseases, in compare with Baylucide as standard drug.展开更多
A series of novel -aminophosphonates containing pyrazole and fluorine moieties was designed and synthesized through ultrasonic-assisted condensation and solvent-free addition reactions. Their structures were verified ...A series of novel -aminophosphonates containing pyrazole and fluorine moieties was designed and synthesized through ultrasonic-assisted condensation and solvent-free addition reactions. Their structures were verified by IR, ^1H NMR, ^13C NMR and elemental analysis. The crystal structure of diethyl[（4-cyano-1H-pyrazol-3-ylamino）（3,5-difluorophenyl）methyl]phosphonate（4a, C15H17F2N4O3P） was determined by single-crystal X-ray diffraction. Compound 4a crystallizes in the triclinic system, space group P1 with a = 8.381（3）, b = 10.103（5）, c = 11.268（3） A, α= 83.772（19）, β= 74.726（19）, γ= 70.964（18）, V = 869.9（6） 3, Mr = 370.30, Dc = 1.414 g/cm^3, Z = 2, F（000） = 384, = 0.200 mm^-1, MoKa radiation（ = 0.71073 ）, the final R = 0.0487 and w R = 0.0823 for 1582 observed reflections with I 〉 2（I）. X-ray diffraction analysis reveals that there are two planes in 4a, and the dihedral angle is 71.51°. Two intermolecular hydrogen bonds and a face-to-face … stacking interaction are observed in the crystal structure. The compounds were evaluated for their antifungal, antiviral and antitumor activities, respectively. Among them, 4b, 4c, 4g and 4h exhibit good activities on Sclerotium rolfsii Sacc at 200 μg/m L, while 4b, 4c, 4f and 4g possess good anti-TMV activities at 500 μg/m L. Unfortunately, all of the compounds showed weak antitumor activities.展开更多
文摘In a recent paper, solution-state ^(19)F NMR spectroscopy was used to probe the conformational dynamics of β-arrestin-1, an essential adaptor and signaling component of the G-protein couple receptor (GPCR) signaling pathway. This work reveals a highly complex conformational energy landscape of β-arrestin-1, and illuminates the molecular mechanism of the membrane phosphoinositide PIP2-induced β-arrestin-1 activation at residue level.(https://doi.org/10.1038/s41467-023-43694-1).
基金the financial support provided by the National Natural Science Foundation of China(Nos.51932005,22072164)Liaoning Revitalization Talents Program(No.XLYC1807175)the Research Fund of Shenyang National Laboratory for Materials Science,the Natural Science Foundation of Jilin Province(Nos.YDZJ202301ZYTS280,YDZJ202201ZYTS305,YDZJ202401316ZYTS).
文摘Fluorine owing to its inherently high electronegativity exhibits charge delocalization and ion dissociation capabilities;as a result,there has been an influx of research studies focused on the utilization of fluorides to optimize solid electrolyte interfaces and provide dynamic protection of electrodes to regulate the reaction and function performance of batteries.Nonetheless,the shuttle effect and the sluggish redox reaction kinetics emphasize the potential bottlenecks of lithium-sulfur batteries.Whether fluorine modulation regulate the reaction process of Li-S chemistry?Here,the TiOF/Ti_(3)C_(2)MXene nanoribbons with a tailored F distribution were constructed via an NH4F fluorinated method.Relying on in situ characterizations and electrochemical analysis,the F activates the catalysis function of Ti metal atoms in the consecutive redox reaction.The positive charge of Ti metal sites is increased due to the formation of O-Ti-F bonds based on the Lewis acid-base mechanism,which contributes to the adsorption of polysulfides,provides more nucleation sites and promotes the cleavage of S-S bonds.This facilitates the deposition of Li_(2)S at lower overpotentials.Additionally,fluorine has the capacity to capture electrons originating from Li_(2)S dissolution due to charge compensation mechanisms.The fluorine modulation strategy holds the promise of guiding the construction of fluorine-based catalysts and facilitating the seamless integration of multiple consecutive heterogeneous catalytic processes.
基金supported by the National Natural Science Foundation of China(51973157,61904123,52103061,52203066)the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(2018KJ196)+3 种基金the project funded by China Postdoctoral Science Foundation(2021T140419)Tianjin Municipal College Student’Innovation and Entrepreneurship Training Program(202110058052)the National Innovation and Entrepreneurship Training Program for College Students(202110058017)the State Key Laboratory of Membrane and Membrane Separation,Tiangong University。
文摘With the popularity and widespread applications of electronics,higher demands are being placed on the performance of battery materials.Due to the large difference in electronegativity between fluorine and carbon atoms,doping fluorine atoms in nanocarbon-based materials is considered an effective way to improve the performance of used battery.However,there is still a blank in the systematic review of the mechanism and research progress of fluorine-doped nanostructured carbon materials in various batteries.In this review,the synthetic routes of fluorinated/fluorine-doped nanocarbon-based(CF_x)materials under different fluorine sources and the function mechanism of CF_x in various batteries are reviewed in detail.Subsequently,judging from the dependence between the structure and electrochemical performance of nanocarbon sources,the progress of CF_x based on different dimensions(0D–3D)for primary battery applications is reviewed and the balance between energy density and power density is critically discussed.In addition,the roles of CF_x materials in secondary batteries and their current applications in recent years are summarized in detail to illustrate the effect of introducing F atoms.Finally,we envisage the prospect of CF_x materials and offer some insights and recommendations to facilitate the further exploration of CF_x materials for various high-performance battery applications.
基金Supported by Guizhou Provincial Science and Technology Projects (QKHJC(2019)1294)Innovation Group Project of Guizhou Provincial Department of Education (QJH-KY-Z[2020]023)+1 种基金Moutai Institute High-level Talents Research Project (MYGCCRC[2022]064)Innovation and Entrepreneurship Training Program for College Students of Moutai Institute (X202214625040)。
文摘In order to find out the effects of soil fluorine on ecological environment and crop safety in the sorghum cultivation base of Renhuai City, Guizhou Province, the content and the occurrence forms of soil fluorine and its influencing factors of Maoba Town were investigated and studied. The results showed that the total fluorine content in the soil of the sorghum base ranged from 668.60 to 2 596.80 mg/kg, with an average of 1 483.25 mg/kg, which was 3.10 and 1.85 times of the national soil background value and the average value of the soil in endemic areas, respectively. The spatial distribution of fluorine in the soil of the study area was uneven, and the fluorine content was in the order of Anliang Village>Yangliu Village>Houba Village>Xiongfeng Village. The soil fluorine contents of various forms varied greatly, and the distribution law was as follows: residual state>water soluble state>organically bound state>exchangeable state>Fe/Mn-F state. The residual fluorine content was the highest, accounting for more than 99% of total fluorine content, while the sum of other four forms was less than 1%, with their respective proportions ranging from 0.10% to 0.30%. The content and proportion of available fluorine in water-soluble and exchangeable states were relatively low, which had limited influence on the surrounding water environment and crop safety. The physicochemical properties of soil, such as pH, organic matter, cation exchange capacity and clay particles had a certain influence on the occurrence forms of soil fluorine, thus changing the availability and migration of soil fluorine, which might endanger the ecological environment safety, food safety and human health.
基金supported by the National Natural Science Foundation of China(No.91963118 and 52102213)Science Technology Program of Jilin Province(No.20200201066JC)the 111 Project(No.B13013).
文摘The high concentration electrolytes with specific solvation structure could passivate the electrodes to prolong battery cycle life but at the expense of increased cost,which limits the wide application in commercialization.The regular concentration(1_(M))electrolytes with suitable properties(viscosity,ionic conductivity,etc.)are cost-guaranteed,but undesired reactions would always occur and lead to battery degradation during long cycles.To promote the long-term cycle stability in a cost-effective way,this work constructs bidirectional fluorine-rich electrode/electrolyte interphase(EEI)by redistribution of solvents and electrochemical induction.The fluorinated effect with reasonable zoning planning restricts morphological disintegration,meanwhile,forms spatial confinement on cathode.In particular,the obtained cathode electrolyte interphase(CEI)gets the ample ability of Na^(+)transport,which benefits from the fluorinated organics arranged in the epitaxy and the hemi-carbonate content acting on the thickness.Thus,the electrochemical long cycling performance of F-NVPOFⅡF-CC full cells is significantly enhanced(the decay rate at 1 C per cycle is as low as 0.01%).Such a fluorine-rich EEI engineering is expected to take transitional layers against the degradation of cells and make ultra-long cycle batteries possible.
文摘The firing tests with clay blocks were undertaken to study thefluorine expulsion and retention char- acteristics of calcium-basedmaterials during the firing of brick clays. The results indicate thatfluorine expulsion begins at approx. 600-700 deg. C, and the mainportion occurs in 800-1000 deg. C. The mode of firing has someeffects on fluorine expulsion. Additives of calcium-based materialcan reduce fluorine expulsion, which is mainly attributed to theincreased formation of CaF_2 during clay firing. In addition, theoptimum addition tests of 6 calcium-based materials with higherefficiency were carried out in a brick kiln. More than 75/100fluorine is retained in the brick body and there is no adverse effecton brick product. This makes it possible for brickyard to achievenon-polluting production.
基金Project 2001KJ11 supported by National investigation of land and resources
文摘Tongshan area,a part of the floodplain of the abandoned Huanghe River, is one of the popular endemic fluorosis areas in East China. One of the reasons is high concentration of fluorine in shallow groundwater. Test results of 36 groundwater samples show that fluorine concentration in shallow groundwater is 0.18–6.7 mg/L and 50 % of the samples exceed the Chinese drinking water quality standard. There exists a significant negative correlation in content between Ca2+ and F - . The correlations between fluorine concentration and other cations (for example Na+, K+, Mg2+) are not significant. The content of dissolved fluorine from the flooding sediments of the Huanghe River that varying from 5.6 mg/kg to 15.2 mg/kg plays an important role in forming the high fluorine groundwater. Usually, the dissolved fluorine content in silt is much higher than that in silty clay and clay. According to the geological investigation fluorine content in deep groundwater (over 60 m) is less than 1.0 mg/L and suitable for drinking, so it is an effective measure to prevent endemic fluorosis by extracting deep groundwater in disease areas.
基金"973 Program"(2006CB202202)The National Natural Science Foundation of China(40572090,40272124)
文摘A detailed comparison was done between the data about the F in coals published at home and abroad, and associated with the special situation in China. An introduction also was made to illuminate the forming, occurrence and accumulation of the F in coals and its potential hazard to human and environment. Analytical data of coal samples were referred to study the great difference of the F content between coals and gangue. The results show that the average value of the F in the coal samples collected in different coalfields of China is 304x10^6, while that of gangue samples is surprisingly 1 319x10^6, especially the F content of coal ash from Bangmai in Yunnan Province reaches 4 800x10^6. It has been proved in many provinces of China that burning the coal and clay mixture can produce F contamination.
基金Project(2010CB630903) supported by the National Basic Research Program of China
文摘In order to determine the mechanism of bacterial tolerance to fluorine,Acidithiobacillus ferrooxidans ATCC 23270 was domesticated and studied under the conditions of different fluorine concentrations and pH values with or without treatment by Proteinase K.The bacterial activities were observed through measuring the changes of solution potentials by platinum electrode with Ag/AgCl reference electrode and the intracellular fluorine was determined by-uorine ion-selective electrode.The results indicated that the tolerance of Acidithiobacillus ferrooxidans ATCC 23270 to fluorine could be obviously improved by domestication,HF was the effective form of fluorine to affect the bacterial activity,and pH increase or concentration change of ions of strong complex ability with fluorine ions in solution could result in false appearance of high fluorine-resistant strain.Some proteins located in cell wall or cell membrane were intimately relative with the bacterial fluorine tolerance.
文摘The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the absorption edge of TiO 2 to shift to a lower energy region. The photocatalytic activity of co doped TiO 2 with anatase phases was found to be 2 4 times higher than that of the commercial TiO 2 photocatalyst Degussa P25 for phenol decomposition under visible light irradiation. The co doped TiO 2 powders only contain anatase phases even at 1000℃. Apparently, ammonium fluoride added retarded phase transformation of the TiO 2 powders from anatase to rutile. The substitutional fluorine and interstitial nitrogen atoms in co doped TiO 2 polycrystalline powder were responsible for the vis light response and caused the absorption edge of TiO 2 to shift to a lower energy region.
基金Financial supports from the National Natural Science Foundation of China(No.50273035)Hangzhou Zhijiang Silicone Chemical Industry Co.,Ltd.are acknowledged.
文摘Siliconated polyurethane （Si-PU） was synthesized using isophorone diisocyanate （IPDI）, hydroxybutyl-terminated polydimethylsiloxane （PDMS）, polytetramethylene ether glycol （PTMG）, polypropylene glycol （PPG）, 1,6-hexanediol （HDO）, dimethylol propionic acid （DMPA） and triethylamine （TEA）. Based on butyl acrylate （BA）, 2, 2, 2-trifluoroethylmethacrylate （TFEMA） and Si-PU as a seed emulsion, a novel core-shell type acrylic-polyurethane hybrid emulsion, containing siloxane and fluorine （F-Si-PU）, was prepared by seeded emulsion polymerization. The contents of siloxane and fluorine were determined according to the feed ratio. Fourier transform infrared spectroscopy （FTIR） was used to identify the chain structures of Si-PU and F-Si-PU. Investigation of transmission electron microscopy （TEM） confirmed the core-shell structure of F-Si-PU emulsion. Measurement results of water contact angle and the swelling ratio in water and n-octane for cured film showed that the water and the oil resistances for F-Si-PU had been significantly improved at a suitable content of fluorine and siloxane.
基金National Natural Science Foundation of China under contract No. 0487013 and Office ofPolar Expedtion of China.
文摘The different forms fluoine in different parts of molting process of krill was analyzed by culture of Antarctic krill (Euphausia superba). The results shaw that fluorine amount in cuticle is up to 90% of total in the krill. During the krill molting process, the fluorine content in cuticle and muscle varies alternatively. This is to say, the fluorine content in new cuticle and muscle is much lower after molted, the fluorine in krill comes from seawater by biological absorption of the krill, and the fluorine absorbed by krill lost with the old cuticle at the end stage of molting process. Meanwhile, the new molting process starts again. The evidence is proved by the change of different forms fluorine content in cuticle and muscle during krill's molting process. At last the author proposes the fluorine enriching process model of Antarctic krill.
基金financially supported by the National Natural Science Foundation of China(No.52071085,51671058)the Science and Technology Commission of Shanghai Municipality(No.19ZR1404200)。
文摘Ni-rich layered oxide LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(x≥0.8)is the most promising cathodes for future high energy automotive lithium-ion batteries.However,its application is hindered by the undesirable cycle stability,mainly due to the irreversible structure change at high voltage.Herein,we demonstrate that F substitution with the appropriate amount(1 at%)is capable for improve the electrochemical performance of LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2) cathode significantly.It is revealed that F substitution can reduce cation mixing,stabilize the crystal structure and improve Li transport kinetics.The resulted LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(1.99)F_(0.01)cathode can deliver a high capacity of 194.4 mAh g^(-1) with capacity retention of 95.5%after 100 cycles at 2 C and 165.2 mAh g^(-1) at 5 C.In-situ synchrotron X-ray technique proves that F ions in the cathode materials can suppress the irreversible phase transition from H2 phase to H3 phase in high voltage region by preventing oxygen gliding in a-b planes,ensuring a long-term cycle stability.
文摘Tailoring the microstructure of pristine TiO2 is essential to narrow its band gap and prolong the charge lifetime. In particular, strategies involving fluorine have been used successfully to tune the surface chemistry, electronic structure, and morphology of TiO2 photocatalysts to improve their photocatalytic activity based on the strong complexation between fluoride ions and TiO2 and the high electronegativity of fluorine. In this review, we summarize the strategies involving fluorine to establish highly efficient TiO2 photocatalytic systems or fabricate highly efficient TiO2 photocatalysts. The main fluorine effects(i.e. the effects of fluorine on photocatalysis) include the following four aspects:(1) Surface effects of fluoride on TiO2 photocatalysis,(2) effects of fluorine doping on TiO2 photocatalysis,(3) fluoride-mediated tailoring of the morphology of TiO2 photocatalysts, and(4) the effects of fluorine on non-TiO2 photocatalysis. Additionally, the unique applications of these fluorine effects in photocatalysis, including selective degradation of pollutants, selective oxidation of chemicals, water-splitting to produce H2, reduction of CO2 to produce solar fuels, and improvement of the thermostability of TiO2 photocatalysts, are reviewed.
基金Supported by the Team Research for Excellent Mid-aged and Young Teachers of Higher Education of Hubei Province (T200707)
文摘A novel compound of 9-[3-oxo-1-（4-bromopheny）-3-phenypropyl]fluorine （3） was synthesized via nucleophilic addition reaction under solvent-free condition. Its structure was determined by IR, 1H NMR, MS, elemental analysis and X-ray diffraction. The crystal of the new compound is of triclinic system, space group P-1 with a=9.7919（16）, b=11.0932（18）, c=11.2534（19） , α=76.927（3）, β=67.452（3）, γ=84.895（3）°, V=1099.7（3） 3, Z=2, Dc=1.369 g/cm3, μ=1.886 mm-1, F（000）=464, R=0.0586 and wR=0.1562 for 3145 observed reflections with Ⅰ 2σ（Ⅰ）. π-π Stacking interactions contribute to the stability of the structure.
文摘A new method for the simultaneous determination of fluorine and iodine in urine by ion chromatography （IC） with electrochemical pretreatment has been developed. The pretreatment was performed in a novel electrochemical oxidationneutralization device （EOND）, in which iodide of the sample was oxidized to iodate and the alkaline digestion sample solution was neutralized. Under the optimized conditions, the limits of detection （LOD, S/N = 3） were 2.5 μg/L for fluoride and 20 μg/L for iodate, respectively. The recoveries were in the range of 93-102% for fluoride and 86-98% for iodate.
基金Project 50239010 supported by the National Natural Science Foundation of China
文摘With the aid of soil column test models,the transport rules of fluorine contaminants in unsaturated stratified soils are discussed. Curves of F-concentrations at different times and sites in the unsaturated stratified soil were ob-tained under conditions of continuous injection of fluoride contaminants and water. Based on the analysis of the actual observation data,the values between computed results and observed data were compared. It is shown that the chemical properties of fluorine ions are active. The migration process of fluorine ions in soils is complex. Because of the effect of adsorption and desorption,the curve of the fluorine ion breakthrough curve is not symmetric. Its concentration peak value at each measuring point gradually decays. The tail of the breakthrough curve is long and the process of leaching and purifying using water requires considerable time. Along with the release of OHˉ in the process of fluorine absorp-tion,the pH value of the soil solution changed from neutral to alkalinity during the test process. The first part of the breakthrough curve fitted better than the second part. The main reason is that fluorine does not always exist in the form of fluorinions in groundwater. Given the long test time,fluorinions possibly react with other ions in the soil solution to form complex water-soluble fluorine compounds. Only the retardation factor and source-sink term have been considered in our numerical model,which may leads to errors of computed values. But as a whole the migration rules of fluorine ions are basically correct,which indicates that the established numerical model can be used to simulate the transport rules of fluorine contaminants in unsaturated stratified soils.
基金Project supported by the National Natural Science Foundation of China (50574031)
文摘Influence of CaO on thermal decomposition of REFCO3 was studied. The results showed that CaO did not affect significantly the decomposition ratio of REFCO3. The XRD experiment showed that there was a great deal of CaF2 in the masting production, the gas chromatographic analysis on the gas of REFCO3 decomposed, and the 70% content of fluorine in the gas of REFCO3 added 15% CaO was reduced. CaO could absorb the fluorine from the decomposition of REFCO3, and the environmental pollution of the fluorine was greatly alleviated,
文摘New fluorine substituted 6-(5’-fluoro-2’-triphenylphosphiniminophenyl) 3-thioxo-1,2,4-triazin-5 (2H, 4H) one (2) was obtained via Wittig’s reaction of the corresponding 6-(5’-fluoro-2’-amino-phenyl)-3-thioxo-1,2,4-triazinone (1). Behavior of compound 2 towards alkylating agents and/or oxidizing agents was studied were, N-hydroxyl (3), Mannich base (4,5), S-alkyl (6,7,8) and thiazolo [3,2-b][1,2,4] triazinones (10-14) and or 3-disulfide (18), 3-sulfonic acid 19 and 1,2,4-triazin-3,5-Dionne (20) derivatives obtained. Structures of the new products are established by elemental and spectral data. The new targets obtained screened as Molluscicidalagents against Biomophlaria Alexandrina snails responsible for Bilharziasis diseases, in compare with Baylucide as standard drug.
基金supported by the Future Talent Project of JXAU(No.09003444)the Doctoral Research Foundation of JXAU(No.09004065)
文摘A series of novel -aminophosphonates containing pyrazole and fluorine moieties was designed and synthesized through ultrasonic-assisted condensation and solvent-free addition reactions. Their structures were verified by IR, ^1H NMR, ^13C NMR and elemental analysis. The crystal structure of diethyl[（4-cyano-1H-pyrazol-3-ylamino）（3,5-difluorophenyl）methyl]phosphonate（4a, C15H17F2N4O3P） was determined by single-crystal X-ray diffraction. Compound 4a crystallizes in the triclinic system, space group P1 with a = 8.381（3）, b = 10.103（5）, c = 11.268（3） A, α= 83.772（19）, β= 74.726（19）, γ= 70.964（18）, V = 869.9（6） 3, Mr = 370.30, Dc = 1.414 g/cm^3, Z = 2, F（000） = 384, = 0.200 mm^-1, MoKa radiation（ = 0.71073 ）, the final R = 0.0487 and w R = 0.0823 for 1582 observed reflections with I 〉 2（I）. X-ray diffraction analysis reveals that there are two planes in 4a, and the dihedral angle is 71.51°. Two intermolecular hydrogen bonds and a face-to-face … stacking interaction are observed in the crystal structure. The compounds were evaluated for their antifungal, antiviral and antitumor activities, respectively. Among them, 4b, 4c, 4g and 4h exhibit good activities on Sclerotium rolfsii Sacc at 200 μg/m L, while 4b, 4c, 4f and 4g possess good anti-TMV activities at 500 μg/m L. Unfortunately, all of the compounds showed weak antitumor activities.
