采用固相烧结法制备ZrV 2-x P x O 7系列材料,研究了P替代对ZrV 2O 7介电和电导性能的影响。研究发现,ZrV 2-x P x O 7系列材料的高频介电常数随着P含量的增加而降低;材料的离子弛豫极化和晶界极化速率随P含量的增加先变大后变小,其介...采用固相烧结法制备ZrV 2-x P x O 7系列材料,研究了P替代对ZrV 2O 7介电和电导性能的影响。研究发现,ZrV 2-x P x O 7系列材料的高频介电常数随着P含量的增加而降低;材料的离子弛豫极化和晶界极化速率随P含量的增加先变大后变小,其介电弛豫时间随P含量的增加先增大再减小,其中ZrV 1.6 P 0.4 O 7具有最大的介电弛豫时间,为5.63×10-4 s。由于P和V离子半径和电负性的差异,P的加入会导致晶格畸变和散射几率变化。室温下,ZrV 2-x P x O 7系列材料的电导率对P的含量非常敏感,ZrV 1.6 P 0.4 O 7具有最大电导率,为5.83×10-5 S·cm-1。对ZrV 1.6 P 0.4 O 7进行变温特性测试发现,其活化能为0.19 eV。对ZrV 2-x P x O 7系列材料的电导率和介电的研究对拓展此类材料在电子器件方面的应用具有重要意义。展开更多
In this paper, the stability of disclination ring in nematie liquid crystals is studied. In the presence of saddle-splay elasticity （characterized by k24） the disclination ring has a universal equilibrium radius. De...In this paper, the stability of disclination ring in nematie liquid crystals is studied. In the presence of saddle-splay elasticity （characterized by k24） the disclination ring has a universal equilibrium radius. Depending on the values of the saddle-splay constant k24, the universal equilibrium radius is altered. When k24 〉 0.92k （m = 1/2） and k24 〉 0.88k （m =-1/2）, the disclination will be a point rather than a ring, where k is the Frank elastic constant in the one-constant approximation.展开更多
A material with the formula ZrMgMo_(3)O_(12) having negative thermal expansion is presented and characterized.It is shown that ZrMgMo_(3)O_(12) crystallizes in an orthorhombic symmetry with space group Pnma(62)or Pna2...A material with the formula ZrMgMo_(3)O_(12) having negative thermal expansion is presented and characterized.It is shown that ZrMgMo_(3)O_(12) crystallizes in an orthorhombic symmetry with space group Pnma(62)or Pna21(33)and exhibits negative thermal expansion in a large temperature range(αl=-3.8×10^(-6) K^(-1) from 300 K to 1000 K by x-ray diffraction andαl=-3.73×10^(-6) K^(-1) from 295 K to 775 K by dilatometer).ZrMgMo_(3)O_(12) remains the orthorhombic structure without phase transition or decomposition at least from 123 K to 1200 K and is not hygroscopic.These properties make it an excellent material with negative thermal expansion for a variety of applications.展开更多
文摘采用固相烧结法制备ZrV 2-x P x O 7系列材料,研究了P替代对ZrV 2O 7介电和电导性能的影响。研究发现,ZrV 2-x P x O 7系列材料的高频介电常数随着P含量的增加而降低;材料的离子弛豫极化和晶界极化速率随P含量的增加先变大后变小,其介电弛豫时间随P含量的增加先增大再减小,其中ZrV 1.6 P 0.4 O 7具有最大的介电弛豫时间,为5.63×10-4 s。由于P和V离子半径和电负性的差异,P的加入会导致晶格畸变和散射几率变化。室温下,ZrV 2-x P x O 7系列材料的电导率对P的含量非常敏感,ZrV 1.6 P 0.4 O 7具有最大电导率,为5.83×10-5 S·cm-1。对ZrV 1.6 P 0.4 O 7进行变温特性测试发现,其活化能为0.19 eV。对ZrV 2-x P x O 7系列材料的电导率和介电的研究对拓展此类材料在电子器件方面的应用具有重要意义。
基金the Natural Science Foundation of Shanghai Municipal Commission of Science and Technology under Grant No.04ZR14059National Natural Science Foundation of China under Grant No.10575068
文摘In this paper, the stability of disclination ring in nematie liquid crystals is studied. In the presence of saddle-splay elasticity （characterized by k24） the disclination ring has a universal equilibrium radius. Depending on the values of the saddle-splay constant k24, the universal equilibrium radius is altered. When k24 〉 0.92k （m = 1/2） and k24 〉 0.88k （m =-1/2）, the disclination will be a point rather than a ring, where k is the Frank elastic constant in the one-constant approximation.
基金Supported by the National Science Foundation of China(Nos 10974183,11104252)the Ministry of Education of China(No 20114101110003)+1 种基金the Fund for Science&Technology Innovation Team of Zhengzhou(No 112PCXTD337)the Postdoctoral Research Sponsorship in Henan Province(No 2011002).
文摘A material with the formula ZrMgMo_(3)O_(12) having negative thermal expansion is presented and characterized.It is shown that ZrMgMo_(3)O_(12) crystallizes in an orthorhombic symmetry with space group Pnma(62)or Pna21(33)and exhibits negative thermal expansion in a large temperature range(αl=-3.8×10^(-6) K^(-1) from 300 K to 1000 K by x-ray diffraction andαl=-3.73×10^(-6) K^(-1) from 295 K to 775 K by dilatometer).ZrMgMo_(3)O_(12) remains the orthorhombic structure without phase transition or decomposition at least from 123 K to 1200 K and is not hygroscopic.These properties make it an excellent material with negative thermal expansion for a variety of applications.
