Satellite communications is not only a key technical for students who major in information subject must know well, but also a satellite cultural background course at the information age. Based on the current situation...Satellite communications is not only a key technical for students who major in information subject must know well, but also a satellite cultural background course at the information age. Based on the current situation and characteristics of Universities of 211 Project, such as teaching objectives, course settings, and too much categories of professional courses but class hour reduced. From the point of view of teaching contents and methods, the reform contents and the characteristic requirements of the satellite communications course are presented, especially, the proposed reform to satellite communications materials and experimental content can meet the needs of the new times.展开更多
Olefin polymerization is one of the most im portant chemical reactions in industry.This work presents a strategy that emphasizes the synergistic meta/poro-steric hindrance of N-aryl groups and electronic effects in ne...Olefin polymerization is one of the most im portant chemical reactions in industry.This work presents a strategy that emphasizes the synergistic meta/poro-steric hindrance of N-aryl groups and electronic effects in newly synthesized neutral salicylaldiminato nickel catalysts.These nickel(Ⅱ)catalysts exhibit exceptional thermostability,ranging from 30℃to 130℃,demonstrating enhanced catalytic activities and broadly regulated polyethylene molecular weights(3-341 kg·mol^(-1))and controlled polymer branch density(2-102 brs/1000C).The preferred catalyst Ni3 with concerted steric and electronic effects enables the production of solid-state semi-crystalline polyethylene materials at temperatures below 90℃.Notably,Ni3 exhibits an impressive tolerance of 110℃and can withstand even the challenging polymerization temperature of 130℃,leading to the production of polyethylene wax and oil.Also,functionalized polyethylene is produced.展开更多
Tumor-induced osteomalacia(TIO)is a rare paraneoplastic syndrome caused by excessive fibroblast growth factor 23(FGF23)production by a tumor,which often arises from a mesenchymal origin.[1-3]Most clinical symptoms of ...Tumor-induced osteomalacia(TIO)is a rare paraneoplastic syndrome caused by excessive fibroblast growth factor 23(FGF23)production by a tumor,which often arises from a mesenchymal origin.[1-3]Most clinical symptoms of TIO are the consequences of prolonged FGF23-mediated hypophosphatemia as muscle weakness,bone pain,impaired mobility,and fractures.[4]Clinical diagnosis and management of TIO are challenging because knowledge about this condition is still restricted to a few specialized centers,leading to delay in diagnosis and appropriate treatment.The scope of the present consensus is to provide up-to-date guidance on the assessment and treatment of TIO.展开更多
Four experimental FGH96 alloys with various contents of Hf and Zr （0 and 0.04%, 0.3% and 0.04%, 0.6% and 0. 04%, 0. 3% and 0.06%, respectively） were produced using PREP （plasma rotating electrode process）＋ HIP （...Four experimental FGH96 alloys with various contents of Hf and Zr （0 and 0.04%, 0.3% and 0.04%, 0.6% and 0. 04%, 0. 3% and 0.06%, respectively） were produced using PREP （plasma rotating electrode process）＋ HIP （hot isostatic pressing） route. The unnotched and notched stress-rupture properties and fatigue crack growth rate （FCGR） of all the experimental alloys were investigated to study the effect of Hf and Zr. Relevant fracture morphol ogy and microstructure were observed by scanning electron microscopy and transmission electron microscopy. The results revealed that appropriate content of Hf could lengthen stress-rupture life, eliminate notch sensitivity and slo wer FCGR. Microstructure analysis showed that the amount of ＂f phase should be increased or decreased by adjusting Hf and Zr contents, and MC carbide and oxide coupled growth should be increased by adding Hf content, which caused oxycarbide to precipitate along grain boundary and strengthen the alloy. It was found that excessive Zr in Hf- containing FGH96 alloy had certain deleterious effects on stress-rupture property because there was strong Zr segre- gation at prior particle boundary, leaving a long chain of large-size oxides along the boundary. The optimal content of Hf and Zr in FGH96 alloy was 0.6% and 0. 04%, respectively.展开更多
For the rational design of metal catalyst in olefin polymerization catalysis,various strategies were applied to suppress the chain transfer by bulking up the axial positions of the metal center,among which the"sa...For the rational design of metal catalyst in olefin polymerization catalysis,various strategies were applied to suppress the chain transfer by bulking up the axial positions of the metal center,among which the"sandwich"type turned out to be an eficient category in achieving high molecular weight polyolefin.In the a-dimine system,the"sandwich"type catalysts were built using the typical 8-aryl-naphthyI framework.In this contribution,by introducing the rotationally restrained benzosuberyl substituent into the ortho-position of N-aryl rings,a new class of "sandwich-like"a-diimine nickel catalysts was constructed and fully identified.The rotationally restrained benzosuberyl substituents played a"sandwich-like"function by capping the nickel center from two axial sites.Compared to the nickel catalyst Ni1 bearing freely rotated benzhydryl substituent,Ni2 featuring benzosubery|substituent enabled the increase(8 times)of polymer molecular weights from 8 kDa to 65 kDa in the polymerization of ethylene.By further increasing the steric bulk of another ortho-site of the N-aryl ring,the polymer molecular weight even reached an ultrahigh level of 833 kDa(Mw=1857 kDa)using the optimized Ni3.Notably,these nickel catalysts could also mediate the copolymerization of ethylene with methyl 10-undecenoate,with Ni3 giving the highest copolymer molecular weight(88 kDa)and the highest incorporation of comonmer(2.0 mol1%),along with high activity of up to 10^(5)g·mol^(-1)·h^(-1).展开更多
In this work,we use commercial powder particulates(a cosmetic fixing powder)as triboelectric materials for constructing a triboelectric nanogenerator(CFP-TENG).Through finger pressing,the CFP-TENG generated approximat...In this work,we use commercial powder particulates(a cosmetic fixing powder)as triboelectric materials for constructing a triboelectric nanogenerator(CFP-TENG).Through finger pressing,the CFP-TENG generated approximate open-circuit voltage,short-circuit current,and maximum power density values of 1141 V,521μA,and 570.96μW/cm^(2),respectively.Thirty-seven commercial blue LEDs can be easily lit up by the CFP-TENG.Moreover,this TENG,which was designed as a novel palette structure for harvesting mechanical energy from bicycle motion,serves as a self-powered bicycle speed sensor.In addition,the cosmetic fixing powder can be used as an effective material to enhance the triboelectric property of skin.This study provides an effective method for developing a cost-effective TENG without the use of complex surface micro-/nano-texturing.展开更多
文摘Satellite communications is not only a key technical for students who major in information subject must know well, but also a satellite cultural background course at the information age. Based on the current situation and characteristics of Universities of 211 Project, such as teaching objectives, course settings, and too much categories of professional courses but class hour reduced. From the point of view of teaching contents and methods, the reform contents and the characteristic requirements of the satellite communications course are presented, especially, the proposed reform to satellite communications materials and experimental content can meet the needs of the new times.
基金financially supported by the National Natural Science Foundation of China(Nos.22122110 and U23B6011 for Z.J.)the Jilin Provincial Science and Technology Department Program(No.20210101070JC for Y.C.)。
文摘Olefin polymerization is one of the most im portant chemical reactions in industry.This work presents a strategy that emphasizes the synergistic meta/poro-steric hindrance of N-aryl groups and electronic effects in newly synthesized neutral salicylaldiminato nickel catalysts.These nickel(Ⅱ)catalysts exhibit exceptional thermostability,ranging from 30℃to 130℃,demonstrating enhanced catalytic activities and broadly regulated polyethylene molecular weights(3-341 kg·mol^(-1))and controlled polymer branch density(2-102 brs/1000C).The preferred catalyst Ni3 with concerted steric and electronic effects enables the production of solid-state semi-crystalline polyethylene materials at temperatures below 90℃.Notably,Ni3 exhibits an impressive tolerance of 110℃and can withstand even the challenging polymerization temperature of 130℃,leading to the production of polyethylene wax and oil.Also,functionalized polyethylene is produced.
基金by grants from the CAMS Innovation Fund for Medical Science(No.2016-I2M-3-003)the National Natural Science Foundation of China(No.81970757 and No.81670714).
文摘Tumor-induced osteomalacia(TIO)is a rare paraneoplastic syndrome caused by excessive fibroblast growth factor 23(FGF23)production by a tumor,which often arises from a mesenchymal origin.[1-3]Most clinical symptoms of TIO are the consequences of prolonged FGF23-mediated hypophosphatemia as muscle weakness,bone pain,impaired mobility,and fractures.[4]Clinical diagnosis and management of TIO are challenging because knowledge about this condition is still restricted to a few specialized centers,leading to delay in diagnosis and appropriate treatment.The scope of the present consensus is to provide up-to-date guidance on the assessment and treatment of TIO.
基金Sponsored by National Basic Research Program of China(2010CB631204)
文摘Four experimental FGH96 alloys with various contents of Hf and Zr （0 and 0.04%, 0.3% and 0.04%, 0.6% and 0. 04%, 0. 3% and 0.06%, respectively） were produced using PREP （plasma rotating electrode process）＋ HIP （hot isostatic pressing） route. The unnotched and notched stress-rupture properties and fatigue crack growth rate （FCGR） of all the experimental alloys were investigated to study the effect of Hf and Zr. Relevant fracture morphol ogy and microstructure were observed by scanning electron microscopy and transmission electron microscopy. The results revealed that appropriate content of Hf could lengthen stress-rupture life, eliminate notch sensitivity and slo wer FCGR. Microstructure analysis showed that the amount of ＂f phase should be increased or decreased by adjusting Hf and Zr contents, and MC carbide and oxide coupled growth should be increased by adding Hf content, which caused oxycarbide to precipitate along grain boundary and strengthen the alloy. It was found that excessive Zr in Hf- containing FGH96 alloy had certain deleterious effects on stress-rupture property because there was strong Zr segre- gation at prior particle boundary, leaving a long chain of large-size oxides along the boundary. The optimal content of Hf and Zr in FGH96 alloy was 0.6% and 0. 04%, respectively.
基金the National Natural Science Foundation of China(Nos.21871250 and 22001244)the Jilin Provincial Science and Technology Department Program(No.20200801009GH).
文摘For the rational design of metal catalyst in olefin polymerization catalysis,various strategies were applied to suppress the chain transfer by bulking up the axial positions of the metal center,among which the"sandwich"type turned out to be an eficient category in achieving high molecular weight polyolefin.In the a-dimine system,the"sandwich"type catalysts were built using the typical 8-aryl-naphthyI framework.In this contribution,by introducing the rotationally restrained benzosuberyl substituent into the ortho-position of N-aryl rings,a new class of "sandwich-like"a-diimine nickel catalysts was constructed and fully identified.The rotationally restrained benzosuberyl substituents played a"sandwich-like"function by capping the nickel center from two axial sites.Compared to the nickel catalyst Ni1 bearing freely rotated benzhydryl substituent,Ni2 featuring benzosubery|substituent enabled the increase(8 times)of polymer molecular weights from 8 kDa to 65 kDa in the polymerization of ethylene.By further increasing the steric bulk of another ortho-site of the N-aryl ring,the polymer molecular weight even reached an ultrahigh level of 833 kDa(Mw=1857 kDa)using the optimized Ni3.Notably,these nickel catalysts could also mediate the copolymerization of ethylene with methyl 10-undecenoate,with Ni3 giving the highest copolymer molecular weight(88 kDa)and the highest incorporation of comonmer(2.0 mol1%),along with high activity of up to 10^(5)g·mol^(-1)·h^(-1).
基金This work was supported by the National Natural Science Foundation of China(Grant No.61804132,Grant No.61674128,Grant No.61731019)the Aeronautical Science Foundation of China(Grant No.ASFC-2017ZC76002).
文摘In this work,we use commercial powder particulates(a cosmetic fixing powder)as triboelectric materials for constructing a triboelectric nanogenerator(CFP-TENG).Through finger pressing,the CFP-TENG generated approximate open-circuit voltage,short-circuit current,and maximum power density values of 1141 V,521μA,and 570.96μW/cm^(2),respectively.Thirty-seven commercial blue LEDs can be easily lit up by the CFP-TENG.Moreover,this TENG,which was designed as a novel palette structure for harvesting mechanical energy from bicycle motion,serves as a self-powered bicycle speed sensor.In addition,the cosmetic fixing powder can be used as an effective material to enhance the triboelectric property of skin.This study provides an effective method for developing a cost-effective TENG without the use of complex surface micro-/nano-texturing.
