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 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
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
GC technology was used to study escaping fluorine in calcined process of mixed rare earth concentrate. The mixed rare earth concentrate and it adding assistant of CaO-NaCl-CaCl2 were calcined at 400～750 ℃ for 30～12...GC technology was used to study escaping fluorine in calcined process of mixed rare earth concentrate. The mixed rare earth concentrate and it adding assistant of CaO-NaCl-CaCl2 were calcined at 400～750 ℃ for 30～120 min, and then total amount of fluorine, exhausting ratio of fluorine, decomposition ratio and the component were determined. The results showed that adding CaO-NaCl-CaCl2 the decomposition ratio was up to 90% at 700 ℃ in 1 h, and the escaping ratio of fluorine decreased from 29.52% to 0.948%. The average inhabitation ratio was 98.39%. This method supplied basis for low energy and clean decomposition of mixed rare earth concentrate.展开更多
Novel 6-(5’-fluoro-2’-diphenylphosphorylanilido)-3-hydrazino-1,2,4-trizin-5 (2H) one (3) is achieved from hydrozinolysis of the corresponding 3-thioxo-analoges 2. Compound 2 is also obtained from phosphorylation of ...Novel 6-(5’-fluoro-2’-diphenylphosphorylanilido)-3-hydrazino-1,2,4-trizin-5 (2H) one (3) is achieved from hydrozinolysis of the corresponding 3-thioxo-analoges 2. Compound 2 is also obtained from phosphorylation of 6-(5’-fluoro-2’-aminophenyl)-3-thioxo-1,2,4-triazin-5(2H) one (1). Novel fluorine substituted isolated and/or fused heterobicyclic nitrogen systems bearing and/or containing, 6-phosphoryl anilido-1,2,4-trizin-5 (2H) one moiety (4 - 22) have been synthesized from ring closure reactions of compound 3 with π-acceptors activated carbon compounds in different medium and conditions. Structures of the products are characterized by MS, IR, UV-VIS, CH, N, and 1H/13CNMR spectral data. The new products have been evaluated as potential inhibitors towards HIV-1 activity.展开更多
ZnO nanoparticles are widely used for the electron transport layers(ETLs)of quantum dots light emitting devices(QLEDs).In this work we show that incorporating fluorine(F)into the ZnO ETL results in significant enhance...ZnO nanoparticles are widely used for the electron transport layers(ETLs)of quantum dots light emitting devices(QLEDs).In this work we show that incorporating fluorine(F)into the ZnO ETL results in significant enhancement in device electroluminescence stability,leading to LT50 at 100 cd m^(−2) of 2,370,000 h in red QLED,47X longer than the control devices.X-ray photo-electron spectroscopy,time-of-flight secondary ion mass spectroscopy,photoluminescence and electrical measurements show that the F passivates oxygen vacancies and reduces electron traps in ZnO.Transient photoluminescence versus bias measurements and capacitance-voltage-luminance measurements reveal that the CF4 plasma-treated ETLs lead to increased electron concentration in the QD and the QD/hole transport layer interface,subsequently decreasing hole accumulation,and hence the higher stability.The findings provide new insights into the critical roles that optimizing charge distribution across the layers play in influencing stability and present a novel and simple approach for extending QLED lifetimes.展开更多
This research aims at making a diagnosis of the presence of arsenic, boron, fluorine and vanadium in the waters from the basin of El Divisorio stream, tributary of Paso de las Piedras reservoir, in the southwest of Bu...This research aims at making a diagnosis of the presence of arsenic, boron, fluorine and vanadium in the waters from the basin of El Divisorio stream, tributary of Paso de las Piedras reservoir, in the southwest of Buenos Aires Province. This storage is used to provide water to the cities of Bahía Blanca and Punta Alta with a population of approximately 400,000 inhabitants. A selective and specific sampling of wells, perforations and superficial watercourses was made in 46 points, in an area of nearly 400 km2. Groundwaters had arsenic (max. 0.114 mg/l) exceeding the reference guideline in 97.3% of the samples, boron (max. 1.42 mg/l), vanadium (max. 0.8 mg/l) and fluorine (max. 6.6 mg/l), being respect- tively, 91.9%, 82.9%, and 67.6%. Regarding the superficial flow, while arsenic concentrations were higher than the limit in 100% of the cases (max. 0.072 mg/l), 88.9% corresponded to elevated boron (max. 1 mg/l) and vanadium (max. 0.23 mg/l) and only 22.2% to fluorine (max. 3.18 mg/l) ones. In all these cases, concentrations exceed the reference guideline values suggested by the World Health Organization, the Argentine Food Code and the Environmental Protec- tion Agency. The presence of these contaminants that finally could determine the quality of the water resource entering the reservoir is attributed to the natural characteristics of the environment since contributions by anthropic actions have not been detected in the area. The most critical sectors in the basin were identified in order to stress the possible negative influence of consuming these waters on the community’s health, with the purpose of reporting the results to institutions, authorities and the population and applying them to preventive medicine.展开更多
F-doping hard carbon(F–HC)was synthesized through a mild fluorination at temperature at relative low temperature as the potential anode for sodium-ion batteries(SIBs).The F-doping treatment to HC expands interlayer d...F-doping hard carbon(F–HC)was synthesized through a mild fluorination at temperature at relative low temperature as the potential anode for sodium-ion batteries(SIBs).The F-doping treatment to HC expands interlayer distance and creates some defects in the graphitic framework,which has the ability to improve Na+storage capability through the intercalation and pore-filling process a simultaneously.In addition,the electrically conductive semi-ionic C–F bond in F–HC that can be adjusted by the fluorination temperature facilitates electron transport throughout the electrode.Therefore,F–HC exhibits higher specific capability and better cycling stability than pristine HC.Particularly,F–HC fluorinated at 100℃ (F–HC100)delivers the reversible capability of 343 mAh/g at 50 mAh/g,with the Coulombic efficiency of 78.13%,and the capacity retention remains as 95.81%after 100 cycles.Moreover,the specific capacity of F–HC100 returns to 340 mAh/g after the rate capability test demonstrates its stability even at high current density.The enhanced specific capacity of F–HC,especially at low-voltage region,has the great potential as the anode of SIBs with high energy density.展开更多
Certain areas in Senegal have a serious problem of high fluoride and salinity in underground water because of soil properties. This water currently used for drink has a bad taste on consumption and caused diseases lik...Certain areas in Senegal have a serious problem of high fluoride and salinity in underground water because of soil properties. This water currently used for drink has a bad taste on consumption and caused diseases like dental fluorosis and skeletal fluorosis. A membrane filtration plant constructed by Pall Corporation was improved through nanofiltration (NF) and Low Pressure Reverse Osmosis (LPRO). Both NF and LPRO membranes were shown applicable for salinity and fluoride ions removal from brackish and high fluorinated drinking water in a remote community. The NF membrane has given a fluorine retention rate varying between 63.3% and 71% while the LPRO membrane allow to reach 97 to 98.9% for fluorine rejection. Highest salinity rejection rates expressed through conductivity measurements are around 46% and 97% for respectively NF and LPRO.展开更多
The new method for simultaneous determination of the concentrations of fluorine and chlorine in river water with double indicative electrodes is developed, and the quantitative analysis formulas that the inputs of ele...The new method for simultaneous determination of the concentrations of fluorine and chlorine in river water with double indicative electrodes is developed, and the quantitative analysis formulas that the inputs of electrode were exchanged by using self-made joints were induced. With this method,the synthetic water samples and the water samples taken from Majiagou River were analyzed. The results of determinations are satisfactory. The relative errors were<10.0% for F and <3.0%for Cl. The recoveries werc 90-101% for F and 90-110% tbr Cl. The relative standard deviations were < 15.2% for F and < 10.1% for Cl-. The advantages of this method is accurate, rapid and simple.展开更多
This paper approaches the transportation of fluorine in the groundwater ofepigene Quarternary aquifer by calculation and laboratory studies.The conclusionthat the enrichment and saturation abilities of fluorite are re...This paper approaches the transportation of fluorine in the groundwater ofepigene Quarternary aquifer by calculation and laboratory studies.The conclusionthat the enrichment and saturation abilities of fluorite are related to the transpor-tation of fluorine in groundwater is reached.They would be conducive to findingthe cause of regional fluorine distribution in the groundwater of North China.展开更多
RE sulfate solution containing fluorine is obtained from bastnasite which is roasted in air and then leached with sulfuric acid. Solvent extraction of Ce4+ with DEHPA in sulphonating kerosene from the solution is inve...RE sulfate solution containing fluorine is obtained from bastnasite which is roasted in air and then leached with sulfuric acid. Solvent extraction of Ce4+ with DEHPA in sulphonating kerosene from the solution is investigated. It is found that fluorine ion is extracted into organic phase with Ce4+. The extraction mechanism is proposed by slope analysis and studying the influence of aqueous acidity, fluorine concentration and DEHPA concentration on CF- /cC4+ in equilibrium organic phase.展开更多
Organic solar cells based on narrow bandgap small-molecule acceptors(SMAs)with highly crystalline characteristics have attracted great attentions for their superiority in obtaining high photovoltaic efficiency.Employi...Organic solar cells based on narrow bandgap small-molecule acceptors(SMAs)with highly crystalline characteristics have attracted great attentions for their superiority in obtaining high photovoltaic efficiency.Employing highly crystalline SMAs to enhance power conversion efficiencies(PCEs)by regulating and controlling morphology and compatibility of donor and acceptor materials has turned out to be an effective approach.In this study,we synthesized three different crystalline SMAs by using fluorine substitution on alkoxyphenyl conjugated side chains to modulate the relationship of crystallinity and morphologies,namely ZY1(zero F atoms),ZY2(two F atoms),and ZY3(four F atoms).The three SMAs show the broad absorption edges and similar frontier orbital energy levels,generating the analogical(over 0.9 V)open circuit voltage(VOC)of the polymer solar cells(PSCs).As a result,the PM6:ZY2-based PSCs yield a PCE of 10.81%with a VOC of 0.95 V,a short-circuit current density(JSC)of 16.154 mA cm^(-2),and a fill factor(FF)of 0.71,which is higher than that of 9.17%(PM6:ZY1)and 6.37%(PM6:ZY3).And the PCE(17.23%)of the PM6:Y6:ZY2 based ternary PSCs is also higher than that of 16.32%PM6:Y6 based binary device.Obviously,the results demonstrate that adding fluorine atoms on the conjugated side chains to construct high crystalline materials is a positive strategy to effectively increase the efficiencies of binary and ternary PSCs.展开更多
The diffusion and the activation of phosphorus in phosphorus and fluorine co-implanted Ge after being annealed by excimer laser are investigated.The results prove that the fluorine element plays an important role in s...The diffusion and the activation of phosphorus in phosphorus and fluorine co-implanted Ge after being annealed by excimer laser are investigated.The results prove that the fluorine element plays an important role in suppressing phosphorus diffusion and enhancing phosphorus activation.Moreover,the rapid thermal annealing process is utilized to evaluate and verify the role of fluorine element.During the initial annealing of co-implanted Ge,it is easier to form high bonding energy FnVm clusters which can stabilize the excess vacancies,resulting in the reduced vacancy-assisted diffusion of phosphorus.The maximum activation concentration of about 4.4 ×10^(20) cm^(-3) with a reduced diffusion length and dopant loss is achieved in co-implanted Ge that is annealed at a tailored laser fluence of 175 mJ/cm^(2).The combination of excimer laser annealing and co-implantation technique provides a reference and guideline for high level n-type doping in Ge and is beneficial to its applications in the scaled Ge MOSFET technology and other devices.展开更多
With increasing research interests in the field of light-matter interactions,various methods have been developed for regulating nonlinear optical(NLO)materials.However,the design and synthesis of organic molecular mat...With increasing research interests in the field of light-matter interactions,various methods have been developed for regulating nonlinear optical(NLO)materials.However,the design and synthesis of organic molecular materials for second-order nonlinear optics remain a great challenge because of the strict requirement of the materials to possess a noncentrosymmetric structure.In this work,two benzothiadiazole(BTD)derivatives referred to as BTD-H and BTD-F were synthesized,and their NLO properties in the crystalline states were studied.It was found that introducing fluorine into the BTD backbone effectively tuned the crystal packing styles of BTD derivatives to a noncentrosymmetric system for effective second-order NLO responses.Such a strategy to induce the noncentrosymmetric structure by introducing the fluorine atoms and halogen interactions may provide guidance for future engineering of organic NLO molecular materials.展开更多
Practical application of a Si anode in a high-energy-density battery cannot be achieved due to the huge volume expansion of these anodes.Researchers have focused on binders of the anode to restrict volume expansion in...Practical application of a Si anode in a high-energy-density battery cannot be achieved due to the huge volume expansion of these anodes.Researchers have focused on binders of the anode to restrict volume expansion in order to address this issue,as the hydrogen bonds and mechanical properties of binders can be used to enhance adhesion and accommodate the volume changes of a Si anode.Herein,we comprehensively consider binders’hydrogen bonds,mechanical properties,stability,and compatibility with the electrolyte solution,and design an ether-/ester-/fluorine-rich composite polymer,named P(TFEMAco-IBVE).The proposed binder formula possesses outstanding stability,adhesion,and mechanical strength;moreover,it can accommodate the dramatic volume changes of a Si electrode and exhibits excellent electrochemical performance,achieving a high areal capacity of about 5.4 mA·h·cm^(-2).This novel polymer design may be applied to other electrode materials in the next generation of lithium-ion batteries.展开更多
Hydrogen-bonded polar nematic liquid crystal series with the general formula n OBAF(n = 7-12) is studied. The mesomorphic characterization is demonstrated through differential scanning calorimetry(DSC) and polarized o...Hydrogen-bonded polar nematic liquid crystal series with the general formula n OBAF(n = 7-12) is studied. The mesomorphic characterization is demonstrated through differential scanning calorimetry(DSC) and polarized optical microscopy(POM). The complexes with short alkyl chains(n = 7, 8) present a wide nematic range and monotropic smectic F mesophase, whereas the longer alkyl chain(n = 10-12) analogues show high melting and low clearing mesomorphic liquid crystals. The thermal range of the mesophase and the birefringence increase with chain length decreasing. Furthermore, the effect of the nanoparticles(LiNbO_(3)) on the thermal and the electrical behavior of 8OBAF are investigated. The presence of LiNbO_(3) nanoparticles increases the conductivity and reduces the resistivity of the complex.展开更多
The physical and electrical properties of BF<sub>2</sub><sup>+</sup> implanted polysilicon films subjectedto rapid thermal annealing（RTA）are presented.It is found that the out diffusion of F ...The physical and electrical properties of BF<sub>2</sub><sup>+</sup> implanted polysilicon films subjectedto rapid thermal annealing（RTA）are presented.It is found that the out diffusion of F and itssegregation at polysilicon/silicon oxide interface during RTA are the major causes of F anomalousmigration.Fluorine bubbles were observed in BF<sub>2</sub><sup>+</sup> implanted samples at doses of 1×10<sup>15</sup> and5×10<sup>15</sup>cm<sup>-2</sup> after RTA.展开更多
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National Natural Science Foundation of China (50574031)
文摘GC technology was used to study escaping fluorine in calcined process of mixed rare earth concentrate. The mixed rare earth concentrate and it adding assistant of CaO-NaCl-CaCl2 were calcined at 400～750 ℃ for 30～120 min, and then total amount of fluorine, exhausting ratio of fluorine, decomposition ratio and the component were determined. The results showed that adding CaO-NaCl-CaCl2 the decomposition ratio was up to 90% at 700 ℃ in 1 h, and the escaping ratio of fluorine decreased from 29.52% to 0.948%. The average inhabitation ratio was 98.39%. This method supplied basis for low energy and clean decomposition of mixed rare earth concentrate.
文摘Novel 6-(5’-fluoro-2’-diphenylphosphorylanilido)-3-hydrazino-1,2,4-trizin-5 (2H) one (3) is achieved from hydrozinolysis of the corresponding 3-thioxo-analoges 2. Compound 2 is also obtained from phosphorylation of 6-(5’-fluoro-2’-aminophenyl)-3-thioxo-1,2,4-triazin-5(2H) one (1). Novel fluorine substituted isolated and/or fused heterobicyclic nitrogen systems bearing and/or containing, 6-phosphoryl anilido-1,2,4-trizin-5 (2H) one moiety (4 - 22) have been synthesized from ring closure reactions of compound 3 with π-acceptors activated carbon compounds in different medium and conditions. Structures of the products are characterized by MS, IR, UV-VIS, CH, N, and 1H/13CNMR spectral data. The new products have been evaluated as potential inhibitors towards HIV-1 activity.
基金Partial support to this work by the Natural Sciences & Engineering Research Council of Canada (NSERC) is gratefully acknowledged
文摘ZnO nanoparticles are widely used for the electron transport layers(ETLs)of quantum dots light emitting devices(QLEDs).In this work we show that incorporating fluorine(F)into the ZnO ETL results in significant enhancement in device electroluminescence stability,leading to LT50 at 100 cd m^(−2) of 2,370,000 h in red QLED,47X longer than the control devices.X-ray photo-electron spectroscopy,time-of-flight secondary ion mass spectroscopy,photoluminescence and electrical measurements show that the F passivates oxygen vacancies and reduces electron traps in ZnO.Transient photoluminescence versus bias measurements and capacitance-voltage-luminance measurements reveal that the CF4 plasma-treated ETLs lead to increased electron concentration in the QD and the QD/hole transport layer interface,subsequently decreasing hole accumulation,and hence the higher stability.The findings provide new insights into the critical roles that optimizing charge distribution across the layers play in influencing stability and present a novel and simple approach for extending QLED lifetimes.
文摘This research aims at making a diagnosis of the presence of arsenic, boron, fluorine and vanadium in the waters from the basin of El Divisorio stream, tributary of Paso de las Piedras reservoir, in the southwest of Buenos Aires Province. This storage is used to provide water to the cities of Bahía Blanca and Punta Alta with a population of approximately 400,000 inhabitants. A selective and specific sampling of wells, perforations and superficial watercourses was made in 46 points, in an area of nearly 400 km2. Groundwaters had arsenic (max. 0.114 mg/l) exceeding the reference guideline in 97.3% of the samples, boron (max. 1.42 mg/l), vanadium (max. 0.8 mg/l) and fluorine (max. 6.6 mg/l), being respect- tively, 91.9%, 82.9%, and 67.6%. Regarding the superficial flow, while arsenic concentrations were higher than the limit in 100% of the cases (max. 0.072 mg/l), 88.9% corresponded to elevated boron (max. 1 mg/l) and vanadium (max. 0.23 mg/l) and only 22.2% to fluorine (max. 3.18 mg/l) ones. In all these cases, concentrations exceed the reference guideline values suggested by the World Health Organization, the Argentine Food Code and the Environmental Protec- tion Agency. The presence of these contaminants that finally could determine the quality of the water resource entering the reservoir is attributed to the natural characteristics of the environment since contributions by anthropic actions have not been detected in the area. The most critical sectors in the basin were identified in order to stress the possible negative influence of consuming these waters on the community’s health, with the purpose of reporting the results to institutions, authorities and the population and applying them to preventive medicine.
基金financially supported by the State Grid Headquarters Science and Technology Project(No.5455DW190009)。
文摘F-doping hard carbon(F–HC)was synthesized through a mild fluorination at temperature at relative low temperature as the potential anode for sodium-ion batteries(SIBs).The F-doping treatment to HC expands interlayer distance and creates some defects in the graphitic framework,which has the ability to improve Na+storage capability through the intercalation and pore-filling process a simultaneously.In addition,the electrically conductive semi-ionic C–F bond in F–HC that can be adjusted by the fluorination temperature facilitates electron transport throughout the electrode.Therefore,F–HC exhibits higher specific capability and better cycling stability than pristine HC.Particularly,F–HC fluorinated at 100℃ (F–HC100)delivers the reversible capability of 343 mAh/g at 50 mAh/g,with the Coulombic efficiency of 78.13%,and the capacity retention remains as 95.81%after 100 cycles.Moreover,the specific capacity of F–HC100 returns to 340 mAh/g after the rate capability test demonstrates its stability even at high current density.The enhanced specific capacity of F–HC,especially at low-voltage region,has the great potential as the anode of SIBs with high energy density.
文摘Certain areas in Senegal have a serious problem of high fluoride and salinity in underground water because of soil properties. This water currently used for drink has a bad taste on consumption and caused diseases like dental fluorosis and skeletal fluorosis. A membrane filtration plant constructed by Pall Corporation was improved through nanofiltration (NF) and Low Pressure Reverse Osmosis (LPRO). Both NF and LPRO membranes were shown applicable for salinity and fluoride ions removal from brackish and high fluorinated drinking water in a remote community. The NF membrane has given a fluorine retention rate varying between 63.3% and 71% while the LPRO membrane allow to reach 97 to 98.9% for fluorine rejection. Highest salinity rejection rates expressed through conductivity measurements are around 46% and 97% for respectively NF and LPRO.
文摘The new method for simultaneous determination of the concentrations of fluorine and chlorine in river water with double indicative electrodes is developed, and the quantitative analysis formulas that the inputs of electrode were exchanged by using self-made joints were induced. With this method,the synthetic water samples and the water samples taken from Majiagou River were analyzed. The results of determinations are satisfactory. The relative errors were<10.0% for F and <3.0%for Cl. The recoveries werc 90-101% for F and 90-110% tbr Cl. The relative standard deviations were < 15.2% for F and < 10.1% for Cl-. The advantages of this method is accurate, rapid and simple.
文摘This paper approaches the transportation of fluorine in the groundwater ofepigene Quarternary aquifer by calculation and laboratory studies.The conclusionthat the enrichment and saturation abilities of fluorite are related to the transpor-tation of fluorine in groundwater is reached.They would be conducive to findingthe cause of regional fluorine distribution in the groundwater of North China.
文摘RE sulfate solution containing fluorine is obtained from bastnasite which is roasted in air and then leached with sulfuric acid. Solvent extraction of Ce4+ with DEHPA in sulphonating kerosene from the solution is investigated. It is found that fluorine ion is extracted into organic phase with Ce4+. The extraction mechanism is proposed by slope analysis and studying the influence of aqueous acidity, fluorine concentration and DEHPA concentration on CF- /cC4+ in equilibrium organic phase.
基金the National Natural Science Foundation of China(Nos.51763017,21602150).
文摘Organic solar cells based on narrow bandgap small-molecule acceptors(SMAs)with highly crystalline characteristics have attracted great attentions for their superiority in obtaining high photovoltaic efficiency.Employing highly crystalline SMAs to enhance power conversion efficiencies(PCEs)by regulating and controlling morphology and compatibility of donor and acceptor materials has turned out to be an effective approach.In this study,we synthesized three different crystalline SMAs by using fluorine substitution on alkoxyphenyl conjugated side chains to modulate the relationship of crystallinity and morphologies,namely ZY1(zero F atoms),ZY2(two F atoms),and ZY3(four F atoms).The three SMAs show the broad absorption edges and similar frontier orbital energy levels,generating the analogical(over 0.9 V)open circuit voltage(VOC)of the polymer solar cells(PSCs).As a result,the PM6:ZY2-based PSCs yield a PCE of 10.81%with a VOC of 0.95 V,a short-circuit current density(JSC)of 16.154 mA cm^(-2),and a fill factor(FF)of 0.71,which is higher than that of 9.17%(PM6:ZY1)and 6.37%(PM6:ZY3).And the PCE(17.23%)of the PM6:Y6:ZY2 based ternary PSCs is also higher than that of 16.32%PM6:Y6 based binary device.Obviously,the results demonstrate that adding fluorine atoms on the conjugated side chains to construct high crystalline materials is a positive strategy to effectively increase the efficiencies of binary and ternary PSCs.
基金Project supported by the National Natural Science Foundation of China(Grant No.61904155)the Science and technology Project of Fujian Provincial Department of Education,China(Grant No.JAT200484)+1 种基金the Natural Science Foundation of Fujian Province,China(Grant No.2018J05115)the Scientific Research Projects of Xiamen University of Technology,China(Grant No.YKJCX2020078).
文摘The diffusion and the activation of phosphorus in phosphorus and fluorine co-implanted Ge after being annealed by excimer laser are investigated.The results prove that the fluorine element plays an important role in suppressing phosphorus diffusion and enhancing phosphorus activation.Moreover,the rapid thermal annealing process is utilized to evaluate and verify the role of fluorine element.During the initial annealing of co-implanted Ge,it is easier to form high bonding energy FnVm clusters which can stabilize the excess vacancies,resulting in the reduced vacancy-assisted diffusion of phosphorus.The maximum activation concentration of about 4.4 ×10^(20) cm^(-3) with a reduced diffusion length and dopant loss is achieved in co-implanted Ge that is annealed at a tailored laser fluence of 175 mJ/cm^(2).The combination of excimer laser annealing and co-implantation technique provides a reference and guideline for high level n-type doping in Ge and is beneficial to its applications in the scaled Ge MOSFET technology and other devices.
基金supported by China International Science and Technology Project (No. 2016YFE0114900)National Natural Science Foundation of China (No. 21761132007)
文摘With increasing research interests in the field of light-matter interactions,various methods have been developed for regulating nonlinear optical(NLO)materials.However,the design and synthesis of organic molecular materials for second-order nonlinear optics remain a great challenge because of the strict requirement of the materials to possess a noncentrosymmetric structure.In this work,two benzothiadiazole(BTD)derivatives referred to as BTD-H and BTD-F were synthesized,and their NLO properties in the crystalline states were studied.It was found that introducing fluorine into the BTD backbone effectively tuned the crystal packing styles of BTD derivatives to a noncentrosymmetric system for effective second-order NLO responses.Such a strategy to induce the noncentrosymmetric structure by introducing the fluorine atoms and halogen interactions may provide guidance for future engineering of organic NLO molecular materials.
基金This study was supported by funding from the National Key Research and Development Program of China(2018YFB0104300)the Key Project of the Sichuan Science and Technology Department(2018GZ0546).
文摘Practical application of a Si anode in a high-energy-density battery cannot be achieved due to the huge volume expansion of these anodes.Researchers have focused on binders of the anode to restrict volume expansion in order to address this issue,as the hydrogen bonds and mechanical properties of binders can be used to enhance adhesion and accommodate the volume changes of a Si anode.Herein,we comprehensively consider binders’hydrogen bonds,mechanical properties,stability,and compatibility with the electrolyte solution,and design an ether-/ester-/fluorine-rich composite polymer,named P(TFEMAco-IBVE).The proposed binder formula possesses outstanding stability,adhesion,and mechanical strength;moreover,it can accommodate the dramatic volume changes of a Si electrode and exhibits excellent electrochemical performance,achieving a high areal capacity of about 5.4 mA·h·cm^(-2).This novel polymer design may be applied to other electrode materials in the next generation of lithium-ion batteries.
文摘Hydrogen-bonded polar nematic liquid crystal series with the general formula n OBAF(n = 7-12) is studied. The mesomorphic characterization is demonstrated through differential scanning calorimetry(DSC) and polarized optical microscopy(POM). The complexes with short alkyl chains(n = 7, 8) present a wide nematic range and monotropic smectic F mesophase, whereas the longer alkyl chain(n = 10-12) analogues show high melting and low clearing mesomorphic liquid crystals. The thermal range of the mesophase and the birefringence increase with chain length decreasing. Furthermore, the effect of the nanoparticles(LiNbO_(3)) on the thermal and the electrical behavior of 8OBAF are investigated. The presence of LiNbO_(3) nanoparticles increases the conductivity and reduces the resistivity of the complex.
文摘The physical and electrical properties of BF<sub>2</sub><sup>+</sup> implanted polysilicon films subjectedto rapid thermal annealing（RTA）are presented.It is found that the out diffusion of F and itssegregation at polysilicon/silicon oxide interface during RTA are the major causes of F anomalousmigration.Fluorine bubbles were observed in BF<sub>2</sub><sup>+</sup> implanted samples at doses of 1×10<sup>15</sup> and5×10<sup>15</sup>cm<sup>-2</sup> after RTA.
