The construction of an unprecedented intertwined spiral solvent channel is driven by weak C–Cl…O and C–H…N interactions based on extraordinary parallel spirals which were structured from supramolecular synthon mac...The construction of an unprecedented intertwined spiral solvent channel is driven by weak C–Cl…O and C–H…N interactions based on extraordinary parallel spirals which were structured from supramolecular synthon macrocycle 1（C44H44N4O4） with a propargylamine backbone. The product is characterized by ^1H NMR, ^13C NMR, IR and HRMS, and further confirmed by single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c, with a = 28.922（3）, b = 8.5069（9）, c = 21.687（2）A^°, β = 130.6320（10）°, V = 4049.4（7） A^°3 and Z = 8. A total of 11874 reflections were collected, of which 4942 were independent（Rint = 0.0590） and 2937 were observed with I 〉 2σ（I）. The final full-matrix least-squares refinement gave R（I 〉 2s（I）） = 0.069 and w R = 0.167, S = 1.05,（Δρ）max = 0.20 and（Δρ）min =-0.22 e·A^1-3. The fluorescence of the product is discussed.展开更多
In the thriving fields of thermal management fields,ceramic films with superior thermal insulation and excellent mechanical properties are in high demand.Nevertheless,the fabrication of ceramic films that combine both...In the thriving fields of thermal management fields,ceramic films with superior thermal insulation and excellent mechanical properties are in high demand.Nevertheless,the fabrication of ceramic films that combine both mechanical performance and low thermal conductivity remains highly challenging.Herein,we report a dual-phase Si_(3)N_(4) nanowire-boron nitride(BN)nanosheet(SNB)with an intertwined structure,where BN nanosheets are firmly intertwined on the surface of Si_(3)N_(4) nanowires.The results demonstrate that the SNB film possesses exceptional mechanical properties,with a tensile strength of 5.25 MPa,representing a 127% improvement over the Si_(3)N_(4) nanowire film(SN)without BN nanosheets incorporation.Simultaneously,benefiting from the interface and cross-linking nodes formed between Si_(3)N_(4) nanowires and BN nanosheets,the thermal conductivity of the SNB film is as low as 0.043 W·m^(–1)·K^(–1),marking a 23% reduction compared to the SN film without BN nanosheets.Furthermore,the all-ceramic component characteristic endows the SNB film with high temperature resistance up to 1200℃.The combination of high strength,low thermal conductivity,and high-temperature resistance enables the SNB film a promising candidate for applications in high temperature environments.展开更多
Die Walküre is the most frequently staged and most popular title of the Ring cycle among classical music enthusiasts.It tells a complex story that involves intertwined relationships between father and daughter,hu...Die Walküre is the most frequently staged and most popular title of the Ring cycle among classical music enthusiasts.It tells a complex story that involves intertwined relationships between father and daughter,husband and wife,brother and sister,and lovers in the epic context of the Nordic mythology.展开更多
The year 2024 marks the tenth anniversary of General Secretary Xi Jinping’s proposal for a new energy security strategy and the start of the second decade of the Belt and Road Initiative.During this year,the internat...The year 2024 marks the tenth anniversary of General Secretary Xi Jinping’s proposal for a new energy security strategy and the start of the second decade of the Belt and Road Initiative.During this year,the international situation grew increasingly complex,with intensifying rivalries among major powers and sporadic occurrences of geopolitical conflicts and localized disturbances.CNPC’s international operations focus on maintaining stability while making progress,successfully overcoming various intertwined risks and achieving new milestones in international business development.For six consecutive years,the overseas equity production has maintained an equivalent of 100 million tons.International trade has achieved stable progress,and engineering services have made new breakthroughs in market expansion,contributing new momentum to CNPC’s establishment as a world-class enterprise.展开更多
The author constructs unitary intertwiners for degenerate C*-algebraic universal principal series of SL(n + 1) over a local field by explicitely normalizing standard intertwining integrals at the level of Hilbert modu...The author constructs unitary intertwiners for degenerate C*-algebraic universal principal series of SL(n + 1) over a local field by explicitely normalizing standard intertwining integrals at the level of Hilbert modules.展开更多
基金supported by the Natural Science Foundation of Anhui Province Education Department(No.KJ2014A141,No.KJ2015A243,No.KJ2016A862)
文摘The construction of an unprecedented intertwined spiral solvent channel is driven by weak C–Cl…O and C–H…N interactions based on extraordinary parallel spirals which were structured from supramolecular synthon macrocycle 1（C44H44N4O4） with a propargylamine backbone. The product is characterized by ^1H NMR, ^13C NMR, IR and HRMS, and further confirmed by single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c, with a = 28.922（3）, b = 8.5069（9）, c = 21.687（2）A^°, β = 130.6320（10）°, V = 4049.4（7） A^°3 and Z = 8. A total of 11874 reflections were collected, of which 4942 were independent（Rint = 0.0590） and 2937 were observed with I 〉 2σ（I）. The final full-matrix least-squares refinement gave R（I 〉 2s（I）） = 0.069 and w R = 0.167, S = 1.05,（Δρ）max = 0.20 and（Δρ）min =-0.22 e·A^1-3. The fluorescence of the product is discussed.
基金This work was supported by the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China(No.136 QP-2015)the Key Scientific and Technological Innovation Research Team of Shaanxi Province(No.2022TD-31)+2 种基金the Key R&D Program of Shaanxi Province(No.2021ZDLGY14-04)the National Training Program of Innovation and Entrepreneurship for Undergraduates(No.XN2022023)the Joint Funds of the National Natural Science Foundation of China(No.U21B2067).
文摘In the thriving fields of thermal management fields,ceramic films with superior thermal insulation and excellent mechanical properties are in high demand.Nevertheless,the fabrication of ceramic films that combine both mechanical performance and low thermal conductivity remains highly challenging.Herein,we report a dual-phase Si_(3)N_(4) nanowire-boron nitride(BN)nanosheet(SNB)with an intertwined structure,where BN nanosheets are firmly intertwined on the surface of Si_(3)N_(4) nanowires.The results demonstrate that the SNB film possesses exceptional mechanical properties,with a tensile strength of 5.25 MPa,representing a 127% improvement over the Si_(3)N_(4) nanowire film(SN)without BN nanosheets incorporation.Simultaneously,benefiting from the interface and cross-linking nodes formed between Si_(3)N_(4) nanowires and BN nanosheets,the thermal conductivity of the SNB film is as low as 0.043 W·m^(–1)·K^(–1),marking a 23% reduction compared to the SN film without BN nanosheets.Furthermore,the all-ceramic component characteristic endows the SNB film with high temperature resistance up to 1200℃.The combination of high strength,low thermal conductivity,and high-temperature resistance enables the SNB film a promising candidate for applications in high temperature environments.
文摘Die Walküre is the most frequently staged and most popular title of the Ring cycle among classical music enthusiasts.It tells a complex story that involves intertwined relationships between father and daughter,husband and wife,brother and sister,and lovers in the epic context of the Nordic mythology.
文摘The year 2024 marks the tenth anniversary of General Secretary Xi Jinping’s proposal for a new energy security strategy and the start of the second decade of the Belt and Road Initiative.During this year,the international situation grew increasingly complex,with intensifying rivalries among major powers and sporadic occurrences of geopolitical conflicts and localized disturbances.CNPC’s international operations focus on maintaining stability while making progress,successfully overcoming various intertwined risks and achieving new milestones in international business development.For six consecutive years,the overseas equity production has maintained an equivalent of 100 million tons.International trade has achieved stable progress,and engineering services have made new breakthroughs in market expansion,contributing new momentum to CNPC’s establishment as a world-class enterprise.
文摘The author constructs unitary intertwiners for degenerate C*-algebraic universal principal series of SL(n + 1) over a local field by explicitely normalizing standard intertwining integrals at the level of Hilbert modules.
