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1.
 用混溶蒸发法制备出一系列高聚物P(EO)n-CuBr2(n=4, 8, 12, 16, 24)薄膜,并详细测量它们在0.1~350 MPa静水压范围内的复阻抗谱、在0.1~2 400 MPa静水压范围内的交流电导率以及介电常数。结果表明:离子电导率对压力的依赖关系(σ-p曲线)是条折线,可分解为四条直线相迭加。进一步做X射线衍射物相分析,它们分别归于PEO非晶相的压力效应、PEO结晶相的压力效应和析出CuBr2新相的压力效应。由此计算出上述三种不同相所对应的激活体积、截止压力各自随高聚物P(EO)n-CuBr2薄膜组分的变化。为减小离子电导率的压力效应提供了物理基础。  相似文献   

2.
选用分子量在500万的聚氧化乙烯和无水溴化铜,通过混溶蒸发法制备出一系列高聚物P(EO)n-CuBr2(n=4,8,12,16,24)薄膜,并在0.1-2443MPa范围不同的静水压下详细测量了它们的相对介电常数。分别探讨了增塑剂(CHH6O3)含量对室温常压下离子电导率和介电常数的影响,及其对高压下离子电导率和介电常数的影响。实验结果表明:P(EO)n-CuBr2薄膜在添加介电常数较高和本体粘度较低的增塑剂C4H6O3后,当其相对浓度npc/ntotal=20%时,不仅使该膜的室坟离子电导率明显提高6.8倍,而且使其在高压力下的离子电导率提高1(0.1-100MPa),至2(350-800MPa)个数量极,非常有利于在高压环境中应用。  相似文献   

3.
谢斌  苏昉  王文楼 《物理学报》1995,44(6):903-910
选用分子量500万的聚氧化乙烯,通过混溶蒸发法制备出一系列高聚物(PEO)_(?)-CuBr_2(n=4,8,12,16,24)薄膜,并在0.1—2443MPa范围不同的流体静压力下测量了它们的相对介电常数,分别探讨了高聚物薄膜在室温常压和高压下离子电导率与介电常数的关系。实验结果证实:添加介电常数较高及本体粘度较低的增塑剂C_4H_6O_3后,当其相对浓度npc/n_c=20%时,不仅该薄膜的室温常压离子电导率明显提高6.8倍,而且其压力下的离子电导率也提高1(0.1—100MPa)至2(350—800 关键词:  相似文献   

4.
 采用惰性气体蒸发和真空原位加压方法,制备了具有清洁界面的平均粒度为14 nm的纳米固体CaF2,并在0.1 MPa~2.2 GPa压力范围内52个不同的静水压下,分别详细测量出其离子电导率σ和相对介电常数随压力变化的规律。讨论指出:(1)离子迁移通道受压后的变化(大于、等于或小于最佳值),是影响离子电导率-压力曲线峰值的主要因素;(2)当压力从0.66 GPa再增加时,lg σ分三段线性下降,可归因于纳米晶体的三种自由体积;(3)界面层空间电荷极化是造成纳米CaF2相对介电常数较大的原因,由此可理解介电常数的压力效应,了提高产品的氟离子电导率,用真空原位加压法制备纳米材料时,应当采用高于0.66 GPa的压力。  相似文献   

5.
 我们用金刚石压砧装置(DAC)高压X射线粉末衍射照相方法,研究了β-BaB2O4晶体的相变。压力从0.1 MPa逐步加至17.6 GPa,发现BBO由室温下的六方相经历了若干次相变后,当压力加至11.5 GPa时,转变为无定形相。在11.5 GPa压力前的相变是可逆的,一旦进入无定形相,则相变是不可逆的。  相似文献   

6.
 利用分子轨道方法MNDO、AM1、PM3等计算了高能炸药RDX(C3H6N6O6)及其中间产物C3H6N5O4 、C3H6N4O2 、(H2C)(N—CH2)(N—CH2)NN、CH2=N—NO2的分子结构与热力学性质。用PM3方法给出了可与实验直接比较的生成热。  相似文献   

7.
 用惰性气体蒸发和真空原位加压方法制备了具有清洁界面的平均粒度16 nm的纳米固体CaF2,并在0.1~2 400 MPa范围不同的静水压下用100 kHz~100 Hz内70种频率,精确测量了纳米CaF2的复平面阻抗谱。分别给出纳米CaF2离子电导率和相对介电常数随流体静压力的变化规律。最后的讨论指出:离子迁移通遭受压后的变化(大于、等于或小于最佳值)是影响离子电导率-压力曲线的主要因素;界面层空间电荷极化是造成纳米CaF2相对介电常数较大的原因,由此界面效应可理解介电常数-压力曲线。  相似文献   

8.
 以(C2H5)2O·BF3和Li3N为原料,于苯热条件下合成氮化硼并研究其相变机理。X射线粉末衍射和傅立叶变换红外吸收光谱分析证明,产物中不仅有hBN和cBN物相存在,而且还发现了正交氮化硼(oBN)和锂硼氮的常压相Li3BN2(O)及高压相Li3BN2(T)存在。分析了Li3BN2在高温高压条件下和在苯热条件下对合成cBN催化机制的差异,探讨了Li3BN2在以Li3N和(C2H5)2O·BF3为原料合成BN的催化机制,提出常压相Li3BN2(O)和高压相Li3BN2(T)分别对生成cBN和oBN起催化作用的观点。  相似文献   

9.
 本文准确测量了0~2.21 GPa流体静压力下整体片状非晶B2O3-0.7Li2O-0.7LiCl-0.10Al2O3及其粉末样品的离子电导率和激活体积。对整片非晶锂离子电导率的压力效应应用离子迁移通道的物理图象给出初步的微观解释。对非晶粉末样品离子电导率的压力效应,则发现是由体电导率、接触电导率及同相界面电导率变化的综合结果。高压实验表明,同相界面效应可使离子电导率提高2.5~16倍,该非晶材料还有潜力可进一步提高其离子电导率。  相似文献   

10.
壬基酚聚氧乙烯醚的冲击压缩实验研究   总被引:1,自引:0,他引:1       下载免费PDF全文
 利用二级轻气炮对有机大分子乳化剂壬基酚聚氧乙烯醚(C35H64O11)进行了系列动高压加载实验。在11~42 GPa冲击压力范围内测量了7个Hugoniot数据。结果表明,在17.8 GPa处,该物质的Hugoniot曲线出现拐折。这一现象意味着在高温高压条件下,壬基酚聚氧乙烯醚体系的分子基团发生了结构性相变。  相似文献   

11.
苏昉  王文楼  谢斌  蒋宗驷  林枫凉 《物理学报》1994,43(10):1648-1657
用混溶蒸发法制备出高聚物(PEO)n-CuBr2(n=4,8,12,16,24)薄膜。并详细测量它们在0.1-350MPa静水压范围的复阻抗谱,以及在0.1-2400MPa静水压范围的交流电导率。结果表明:离子电导率与压力的依赖关系可分解为四段相迭加的线性关系。根据X射线衍射物相分析,它们分别归于PEO非晶相的压力效应,PEO结晶相的压力效应和析出新相CuBr2的压力效应。最后给出克服办法——添加少量增塑剂碳酸乙烯酯可增加(PEO)n-CuBr2薄膜的弹性,使压力下的离子电导率提高一至两个数量级。 关键词:  相似文献   

12.
The effects of annealing on the chemical states of N dopant, electrical, and optical properties of N-doped ZnO film grown by molecular beam epitaxy (MBE) are investigated. Both the as-grown ZnO:N film and the film annealed in N2 are of n-type conductivity, whereas the conductivity converts into p-type conductivity for the film annealed in O2. We suggest that the transformation of conductivity is ascribed to the change in ratio of the N molecular number on O site (N2)O to the N atom number on O site (NO) in ZnO:N films under the various annealed atmosphere. For the ZnO:N film annealed in N2, the percentage content of (N2)O is larger than that of NO, i.e.the ratio >1, resulting in the n-type conductivity. However, in the case of the ZnO:N film annealed in O2, the percentage content of (N2)O is fewer than that of NO, i.e., the ratio <1, giving rise to the p-type conductivity. There is an obvious difference between low-temperature (80K) PL spectra of ZnO:N film annealed in N2 and that of ZnO:N film annealed in O2. An emission band located at 3.358eV is observed in the spectra of the ZnO:N film after annealed in N2, this emission band is due to donor-bound exciton (D0X). After annealed in O2, the PL of the donor-bound exciton disappeared, an emission band located at 3.348eV is observed, this emission band is assigned to acceptor-bound exciton (A0X).  相似文献   

13.
Indium tin oxide (ITO) thin films (200-400 nm in thickness) have been grown by pulsed laser deposition (PLD) on glass substrates without a post-deposition anneal. The electrical and optical properties of these films have been investigated as a function of substrate temperature and oxygen partial pressure during deposition. Films were deposited at substrate temperatures ranging from room temperature to 300 °C in O2 partial pressures ranging from 0.1 to 100 mTorr. For 300 nm thick ITO films grown at room temperature in oxygen pressure of 10 mTorr, the electrical conductivity was 2.6᎒-3 Q-1cm-1 and the average optical transmittance was 83% in the visible range (400-700 nm). For 300 nm thick ITO films deposited at 300 °C in 10 mTorr of oxygen, the conductivity was 5.2᎒-3 Q-1cm-1 and the average transmittance in the visible range was 87%. Atomic force microscopy (AFM) measurements showed that the RMS surface roughness for the ITO films grown at room temperature was ~7 Å, which is the lowest reported value for the ITO films grown by any film growth technique at room temperature.  相似文献   

14.
 利用X射线衍射和Eu2+发射光谱方法研究了非晶玻璃SrB4O7在高温高压下的晶化。结果表明:在5.0 GPa压力下,200 ℃仍为玻璃态,只有几个强度极低的小峰,表明有晶化的迹象;600 ℃时已基本晶化,但为SrB4O7正交相与SrB4O7高压立方相二相共存;当温度提高到1 000 ℃时,晶化成了近单相的与常压SrB4O7粉末晶体相同的正交结构。伴随晶化度的加强,Eu2+发射强度增强,与X射线衍射结果相一致。  相似文献   

15.
 本文研究了冷压(2.2~5.2 GPa)与热压(2.2 GPa,2.50~950 ℃)对YBa2Cu3O7-δ的正交→四方相转变区和超导电性的影响。冷压保持其正交结构,但破坏了超导性,在98 K(失超点)到室温呈半导体特性,再在空气中烧结,可恢复液氮温区的零电阻状态。以Cu锅密封样品,热压处理至950 ℃,不发生Cu的析出。热压处理后,98 K(失超点)到室温呈半导体特性,再经通氧烧结,于86 K出现零电阻。热压处理过程,从450~950 ℃为正交→四方转变区。950 ℃为转变结束温度,大大高于氧气、空气、氮气、真空状态的温度。400 ℃附近为起始转变温度,低于氮气、氧气气氛的温度。因此相变区加宽。T0-t结束温度升高,与Cu锅的抑制还原作用有密切关系。如降低高压淬火速率(<<102 ℃/s),或随后辅以氧气氛中的后处理,将有利于获得既有高密度又有高Tc的YBa2Cu3O7-δ超导体。  相似文献   

16.
High pressure behavior of sodium titanate nanotubes (Na2Ti2O5) is investigated by Raman spectroscopy in a diamond anvil cell (DAC) at room temperature. The two pressure-induced irreversible phase transitions are observed under the given pressure. One occurs at about 4.2 GPa accompanied with a new Raman peak emerging at 834 cm-1 which results from the lattice distortion of the Ti-O network in titanate nanotubes. It can be can be assigned to Ti-O lattice vibrations within lepidocrocite-type (H0.7Ti1.825V0.175O4&#12539;H2O)TiO6 octahedral host layers with V being vacancy. The structure of the nanotubes transforms to orthorhombic lepidocrocite structure. Another amorphous phase transition occurs at 16.7 GPa. This phase transition is induced by the collapse of titanate nanotubes. All the Raman bands shift toward higher wavenumbers with a pressure dependence ranging from 1.58-5.6 cm-1/GPa.  相似文献   

17.
孟祥国  范洪义  王继锁 《中国物理 B》2010,19(7):70303-070303
Noticing that the equation ((d~2O_n)/(d_t~2)={H_c,{H_c,O_n }}=λO_n with double-Poisson bracket,where O_n is normal coordinate,H_c is classical Hamiltonian,is the classical correspondence of the invariant eigen-operator equation (2004 Phys.Lett.A.321 75),we can find normal coordinates in harmonic crystal by virtue of the invariant eigen-operator method.  相似文献   

18.
High quality Co-doped ZnO thin films are grown on single crystalline Al2O3(0001) and ZnO(0001) substrates by oxygen plasma assisted molecular beam epitaxy at a relatively lower substrate temperature of 450℃. The epitaxial conditions are examined with in-situ reflection high energy electron diffraction (RHEED) and ex-situ high resolution x-ray diffraction (HRXRD). The epitaxial thin films are single crystal at film thickness smaller than 500nm and nominal concentration of Co dopant up to 20%. It is indicated that the Co cation is incorporated into the ZnO matrix as Co^2+ substituting Zn^2+ ions. Atomic force microscopy shows smooth surfaces with rms roughness of 1.9 nm. Room-temperature magnetization measurements reveal that the Co-doped ZnO thin films are ferromagnetic with Curie temperatures Tc above room temperature.  相似文献   

19.
Films of La0.5Sr0.5CoO3 (LSCO) have been deposited on specially treated TiO2-terminated (001) SrTiO3 substrate surfaces and on macroporous polycrystalline !-Al2O3 substrates, having a mean pore diameter of 80 nm, by pulsed laser deposition. The films deposited on SrTiO3 are good conducting, (001) textured, and exceptionally smooth (1-2 Å for 100 nm thick films). LSCO films deposited on porous !-Al2O3 are polycrystalline and exhibit good crystallographic and electrical properties despite the large substrate roughness and the differences in lattice parameters and crystal structure between the film and the substrate. Different growth modes have been observed on the porous !-Al2O3 substrates depending on the oxygen pressure during film deposition. Films grown at an oxygen pressure of 10-1 mbar are macroporous, whereas films grown at 10-2 mbar completely cover the substrate pores. In the latter case, strain effects lead to film cracking.  相似文献   

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