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研究了Yb3 掺杂铝氟磷酸盐 (AFP)玻璃的吸收光谱、荧光光谱 ,测量了Yb3 离子的荧光有效线宽 (Δλeff>5 5nm)以及2 F5 2 能级的荧光寿命 (τmax=2ms)及随掺杂浓度的变化 .应用倒易法计算了Yb3 的发射截面 ,其发射截面可达 0 6 6 82 3pm2 ,且激光增益系数τfσemi达 1 2 89ms.pm2 .评估了Yb3 在AFP玻璃中的激光性能 ,发现其具有较理想的激发态最小粒子数 (0 15 )、饱和抽运强度 (8 3kW cm2 )和最小抽运强度 (1 2 4 5kW cm2 )值及良好的热稳定性 .研究结果表明掺Yb3 氟磷酸盐玻璃是实现高功率超短可调谐激光器的理想增益介质 . 相似文献
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Fluorination of Dioxa- and Oxazaphospholanes The fluoridolysis of cyclic esters and esteramides of phosphorous acid ( 1 , 2 , 4 , 5 , 7 , 11 , and 12 ,) using the acid fluorination reagent Et3N · nHF (n > 1) or an excess of a basic composed agent (n < 1) yields in all cases HPF5? ( 3 ,). With stoichiometric amounts of fluoride, however, the fluorophospholanes ( 4 ,) and ( 5 ,) as well as fac.- and mer.-o- ( 6a, 6b ,) and the spirocyclic fluorohydridophosphate ( 8 ,) are obtained. ( 13 ,) reacts to ( 14 ,) and the spirocyclic compound ( 15 ,) gives ( 16 ,). The fluorophosphoranes ( 18 ,), ( 19 ,), and ( 21 ,) are obtained by oxidative fluorination of the spiro- or bicyclic P? H compounds 11, 12 , and 20 , with CCl4/Et3N · nHF (n < 1). The oxidative fluorination of the cyclic triesters of phosphorous acid 7 , and 23 , leads to the cyclic fluorophosphates ( 22 ,) and 16 , as well as 6. , The compounds 18, 19 , and 22 , are also formed by oxidative fluorination of elemental phosphorus, P4, in the presence of the corresponding bifunctional nucleophile. 相似文献
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添加适量的葡萄糖并用高温固相法合成钠离子电池正极材料NaVPO4F。用X射线衍射仪、扫描电镜等对NaVPO4F进行结构表征,采用循环伏安、交流阻抗技术等对其进行电化学性能测试,探讨了不同掺碳量对NaVPO4F结构和电化学性能的影响。恒流充放电测试结果显示,掺碳10wt%的NaVPO4F在0.1C倍率下首次充、放电容量分别达到151.5 mAh·g-1和113 mAh·g-1,充、放电平台分别为3.8 V和3.6 V,经过20次循环,放电比容量的保持率为初始的91.6%。循环伏安曲线出现明显的氧化还原峰,并分别与充、放电电位平台相对应。交流阻抗图谱显示,掺碳10wt%的NaVPO4F样品充放电阻抗较小,可逆性较好。 相似文献
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Ruthenium‐Oxide‐Coated Sodium Vanadium Fluorophosphate Nanowires as High‐Power Cathode Materials for Sodium‐Ion Batteries
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Manhua Peng Biao Li Huijun Yan Dongtang Zhang Prof. Xiayan Wang Prof. Dingguo Xia Prof. Guangsheng Guo 《Angewandte Chemie (International ed. in English)》2015,54(22):6452-6456
Sodium‐ion batteries are a very promising alternative to lithium‐ion batteries because of their reliance on an abundant supply of sodium salts, environmental benignity, and low cost. However, the low rate capability and poor long‐term stability still hinder their practical application. A cathode material, formed of RuO2‐coated Na3V2O2(PO4)2F nanowires, has a 50 nm diameter with the space group of I4/mmm. When used as a cathode material for Na‐ion batteries, a reversible capacity of 120 mAh g?1 at 1 C and 95 mAh g?1 at 20 C can be achieved after 1000 charge–discharge cycles. The ultrahigh rate capability and enhanced cycling stability are comparable with high performance lithium cathodes. Combining first principles computational investigation with experimental observations, the excellent performance can be attributed to the uniform and highly conductive RuO2 coating and the preferred growth of the (002) plane in the Na3V2O2(PO4)2F nanowires. 相似文献
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A new one-dimensional aluminum fluorophosphate, AlP2O5(OH)3F·0.5[H2dien] (dien=diethylenetriamine), was solvothermally synthesized by using organic amine as the structure directing agent, and its structure was determined by single-crystal X-ray diffraction. The complex inorganic architecture consists of trans-corner-sharing AlO4F2 octahedra chain decorated by phosphate tetrahedra along both sides of the -F-Al-F-Al-F- backbone displaying a series of Al2P three-membered rings, which will represent a new fundamental structural type in metal phosphates. The results of CHN elemental analysis, EDS, and TGA are also presented. Crystal data: C4H18Al2F2N3O16P4, monoclinic, space group P21/c with a=6.9107(14), b=15.749(3), c=8.9741(18) , β=109.829(2)o, V=918.8(3) 3, Z=2, Mr=580.05, Dc=2.097 g/cm3, μ=0.618 mm-1, S=1.022, F(000)=590, the final R=0.0510 and wR=0.1284 for 1607 observed reflections (I > 2σ(I)). 相似文献
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Dr. Stefan Wagner Matteo Accorsi Prof. Dr. Jörg Rademann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2017,23(61):15387-15395
α,α-Difluoro-benzyl phosphonates are currently the most popular class of phosphotyrosine mimetics. Structurally derived from the natural substrate phosphotyrosine, they constitute classical bioisosteres and have enabled the development of potent inhibitors of protein tyrosine phosphatases (PTP) and phosphotyrosine recognition sites such as SH2 domains. Being dianions bearing two negative charges, phosphonates, however, do not permeate membranes and thus are often inactive in cells and have not been a successful starting point toward therapeutics, yet. In this work, benzyl phosphonates were modified by replacing phosphorus-bound oxygen atoms with phosphorus-bound fluorine atoms. Surprisingly, mono-P-fluorophosphonates were fully stable under physiological conditions, thus enabling the investigation of their mode of action toward PTP. Three alternative scenarios were tested and mono-P-fluorophosphonates were identified as stable reversible PTP1B inhibitors, despite of the loss of one negative charge and the replacement of one oxygen atom as an H-bond donor by fluorine. In extending this replacement strategy, α,α-difluorobenzyl penta-P-fluorophosphates were synthesized and found to be novel phosphotyrosine mimetics with improved affinity to the phosphotyrosine binding site of PTP1B. 相似文献
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A.K. Gupta 《Tetrahedron letters》2008,49(14):2232-2235
The use of trichloroacetonitrile and KF mixture is described as an efficient reagent for the direct conversion of dialkylphosphites to their corresponding dialkyl fluorophosphates via in situ formation of dialkyl chlorophosphates in one-pot. 相似文献
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Difluorodioxophosphates may be used as ceramic phosphate precursor, and their thermal behaviours are very important. In this paper we study by TG and DTA the thermal stability for iron(II) salt. In argon atmosphere, we obtain in a first time the melting of salt at 240°C then the classical breaking up into solid orthophosphate and POF3 exhaust. If the sample of iron(II) difluorodioxophosphate is heating in air, we do not obtain the melting phenomena, but at the same temperature an exothermic phenomenon that conducts to the formation of iron(III). We observe a mass increase. By IR analysis, we can show that this oxidation is obtained without change of difluorodioxophosphate structure. 相似文献
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