Li2B4O7晶体生长及其二次谐波系数

用恰克拉斯基（Ｃｚｏｃｈｒａｌｓｋｉ）法特殊工艺生长出尺寸为Φ３０×３０ｍｍ的优质Ｌｉ２Ｂ４Ｏ７单晶，讨论了工艺参数对晶体宏观缺陷的影响。用Ｍａｋｅｒ条纹测量了晶体的二次谐波系数ｄ３１和ｄ３３，结果表明，Ｌｉ２Ｂ４Ｏ７的ｄ３３是石英晶体ｄ１１的三倍。     

PZT－95／5压电陶瓷的冲击波活化改性研究

研究了冲击波对ＰＺＴ－９５／５压电陶瓷的活化改性作用，对ＰＺＴ－９５／５粉末及块状材料进行动态冲击波加载。实验表明：在合适的条件下，冲击波作用可提高样品的密度ρ，压电应变常数ｄ３３，介电常数ε，降低介电耗损系数ｔｇδ％。通过对样品进行Ｘ射线衍射，扫描电镜ＳＥＭ、透射电镜ＴＥＭ和Ｘ射线光电子能谱ＸＰＳ等微观测试分析，揭示了冲击波改性的机理主要是：晶粒细化，晶界破坏，孔隙增多，缺陷增多，相变产生等，从而达到对样品改性的作用     

激光干涉法测压电陶瓷的压电常数d31

介绍迈克尔逊干涉仪原理在测微小位移中的应用。确定一种锆钛酸铅镧压电陶瓷的压电常数ｄ３１，得到了一种测ｄ３１的可行可靠的新方法。     

Gd1-xCaxBa2Cu3O7-y高温超导体压力效应的研究

研究了Ｇｄ_1-xＣａ_xＢａ₂Ｃｕ₃Ｏ_7-y（０．０≤Ｘ≤０．２０）高温超导体在常压和高压下的超导电性在１－３００Ｋ温度范围内，利用Ｂｒｉｄｇｍａｎ对顶砧获得压力达９．０ＧＰａ，测量了（Ｘ＝０．１０，０．１５，０．２０）样品的ｄＴ_c／ｄｐ分别为７．６８，７．８和４．４６Ｋ／ＧＰａ。发现Ｔ_c的压力导数随着ｃａ²⁺含量的增加而下降，分析了氧含量对Ｔ_c和ｄＴ_c／ｄＰ的影响．利用常压下晶格参数精修值和阳离子与氧离子间距随压力的改变，说明ＣｕＯ₂面在超导电性上的作用，用ＣｕＯ₂面之间耦合解释Ｔ_c（Ｐ）曲线的非线性关系。 关键词：     

0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3单晶/环氧树脂1-3型复合材料的压电性能研究

模拟了0.7Pb(Mg_1/3Nb_2/3)O₃-0.3PbTiO₃(PMN-0.3PT)单晶1-3型压电复合材料的性能与单晶体积分数的关系,得出性能最优时压电相的体积分数为64%, 在这一体积分数下,采用切割-填充法,并使用了不同类型的环氧树脂填充制备复合材料.系统地研究了聚合物相对复合材料性能的影响,研究表明,减小聚合物相的刚度系数c和密度ρ有利于提高复合材料的性能,且聚合物相与压电相的结合强度对性能的影响非常明显,制备的PMN-0.3 PT单晶1-3型复合材料的厚度伸缩机电耦合系数k_t高达90.1%,压电系数d₃₃大于1000pC/N,机械品质因数Q_m为10.39,声阻抗Z也大大降低,性能明显优于传统的Pb(Zr_xTi_1-x)O₃(PZT)陶瓷及其1-3复合材料,在压电换能器和传感器中显示出广阔的前景. 关键词： PMN-PT单晶 压电复合材料 压电相 聚合物相     

Ⅱ-Ⅵ族稀磁半导体Cd_(1-x)Mn_xTe/Cd_(1-y)Mn_yTe超晶格的光调制反射谱的研究

本文报道用分子束外延（ＭＢＥ）技术生长的Ｃｄ１－ｘＭｎｘＴｅ／Ｃｄ１－ｙＭｎｙＴｅ超晶格样品在８０Ｋ下的光调制反射谱实验结果。观测到１１Ｈ、２２Ｈ、３３Ｈ和１１Ｌ等激子跃迁结构。计及晶格失配导致的应力效应，对子能级结构进行了理论计算。实验结果与理论计算符合较好。     

Ⅱ—Ⅵ族稀磁半导体Cd1—xMnxTe／Cd1—yMnyTe超晶格的光调制反 …

本文报道用分子束外延技术生长的Ｃｄ１－ｘＭｎｘＴｅ／Ｃｄ１－ｙＭｎｙＴｅ超晶格样品在８０Ｋ下的光调制反射谱实验结果，观测到１１Ｈ，２２Ｈ，３３Ｈ和１１Ｌ等激子跃迁结构。计及晶格失配导致的应力效应，对子能级结构进行了理论计算。     

溶胶-凝胶法制备的高压电常数（Bi0.5Na0.5）1－xBaxTiO3系无铅压电陶瓷

测量了使用溶胶-凝胶工艺制备的(Bi0.5Na0.5)1-xBaxTiO3(x=0.00，0.04，0.06，0.08,0.12)系陶瓷的介电、压电、铁电和热释电性能.由于使用了溶胶-凝胶工艺制备的粉料，因此所有样品的压电性能都得到了较大提高.其中(Bi0.5Na0.5)0.94Ba0.06TiO.3系陶瓷具有该系列最大的压电常数，d33=173×10-12C/N，与传统工艺相比，d33提高了近40%.同时，在一定范围内，随Ba含量的增加，材料的剩余极化Pr和矫顽场Ec逐渐减小，退极化温度逐渐降低.对于(Bi0.5Na0.5)0.94Ba0.06TiO.3系陶瓷，剩余极化和矫顽场分别为25μC/cm2和28kV/cm，退极化温度约为80℃. 关键词： 溶胶-凝胶 压电常数 剩余极化 矫顽场     

非化学计量和掺杂对(Na1/2Bi1/2)0.92Ba0.08TiO3陶瓷电性能的影响

研究了非化学计量和掺杂对无铅压电陶瓷(Na_1/2Bi_1/2)_0.92Ba_0.08TiO₃的压电性能及去极化温度的影响.研究发现A位非化学计量可以提高陶瓷的压电性能;B位掺杂对材料电学性能的影响规律类似于Pb(Ti,Zr)O₃系压电陶瓷的相关规律;由于非化学计量和掺杂会影响到A位离子对B位离子与氧离子形成的BO₆八面体的耦合作用,影响到畴的稳定性,从而影响 关键词： 无铅压电陶瓷 非化学计量 掺杂 电性能     

压电调制反射光谱研究GaAs/Al0.29Ga0.71As单量子阱

报道了压电调制反射测量系统的建立，应用该系统获得了势阱宽度分别为5nm和25nm的两个G aAs/Al_0.29Ga_0.71As单量子阱的压电调制反射谱. 从图谱中可以看 出，在室 温下能够较容易地分辨出和轻、重空穴相关联的子带跃迁. 在阱宽25nm的样品中还观察到了 自旋-轨道跃迁. 利用有效质量理论近似计算，对量子阱样品的图谱结构进行了指认，发现 实验值和计算值能够较好地符合. 关键词： 压电调制反射光谱 单量子阱 分子束外延     

聚丙烯蜂窝膜驻极体压电系数的测量及压电性的改善

利用介电谐振谱分析了聚丙烯蜂窝状原生膜(PPCellular,PQ50型)的力学及介电参数，测得其压电系数d33约为18pC/N.经合理的压力膨化工艺处理后，其d33可增加至367pC/N，比久负盛名的铁电聚合物聚偏氟乙烯(PVDF)的d33高20倍以上，也高于压电陶瓷锆钛酸铅(PZT)的相应值.结合扫描电镜照片及根据PP蜂窝膜压电理论模型分析了这类空间电荷型非极性孔洞薄膜驻极体呈现高压电系数的结构和物理根源. 关键词： 聚丙烯蜂窝膜 压电性 介电谐振 压力膨化处理     

钛酸钡单晶沿垂直解理面方向的超高压电响应的研究

研究了钛酸钡单晶沿着解理面的压电响应. 首先发现在钛酸钡单晶中存在着解理面，当垂直 这一解理面方向施加电场时，得到了超过2000pC/N的超高压电常量d33. 而这一d 33值比沿着自发极化方向〈001〉方向施加电场得到的压电常量（d33〈001 〉=87pC/N）高20多倍. 而且，沿此方向在很低电场强度（低于1kV/mm）下得到了高达0 6%的应变值，这一应变值是同等场强下PMN_PT单晶的10倍之多. 这一结果无疑对发展无铅压 电材料驱动器提供了一种新可能. 关键词： 压电响应 解理面 钛酸钡单晶     

Effects of Li Substitution and Sintering Temperature on Properties of Bi0.5（Na,K）0.5TiO3 Lead-Free Piezoelectric Ceramics

Bi0.5 （Na0.72K0.28- x Lix ）0.5 TiO3 （BNKLT- 100x） lead-free piezoelectric ceramics are synthesized by conventional solid state sintering techniques. The dielectric and piezoelectric properties of the BNKLT-100x ceramics as a function of Li content are systematically investigated. It is found that not only Li content but also the sintering temperature has a strong effect on the piezoelectric properties of BNKLT. The piezoelectric constant d33 Of BNKLT varies from 120 to 252pC/N in the Li content range from 0.03 to 0.16. In the sintering temperature range from 1080 to 1130℃, the d33 value of BNKLT-6 changes from 200pC/N to 252pC/N. The BNKLT-6 sample sintered at 1100℃ has the highest piezoelectric constant d33 of 252pC/N, with the electromechanical coupling factors kp of 0.32 and kt of 0.44.     

热膨胀处理的聚丙烯蜂窝膜驻极体的压电性

研究了两种商用聚丙烯蜂窝膜(PPCellular)(EUH75和SHD50)的压电性.通过热膨胀技术处理测得上述两种商品膜的压电d33系数分别可达219pC／N和196pC／N.它们比未经处理的样品提高了约两个数量级，而比著名的铁电聚合物PVDF高出一个数量级以上.在强介电气体六氟化硫(SF6)中用高达60kV的电晕电压对EUH75和SHD50样品充电后，讨论了对其压电d33系数的影响的明显差异及其差异的结构根源. 关键词： PP蜂窝膜 压电性 热膨胀技术 介电气体     

Study of 1-3 PZT fibre/epoxy composite force sensor

Lead zirconate titanate (PZT) fibres were prepared by a powder-based extrusion method. Pre-sintered PZT powder mixed with poly(acrylic acid) was spun in a spinnerette to produce fibres. The fibre of ∼400 μm diameter was used to fabricate 1-3 PZT fibre/epoxy composite discs with different volume fractions (ϕ) of PZT. Since the ceramic fibres are rather brittle, their elastic properties cannot be measured directly. In order to determine the properties of the ceramic fibres, effective properties of the fibres/epoxy 1-3 composite were measured. By using a modified series and parallel model, the properties of 1-3 composites can be calculated. Then, the elastic coefficient s_33,fibre^E, relative permittivity ε_33,fibre^T and piezoelectric strain coefficient d_33,fibre of the ceramic fibre could be found. Ring-shaped PZT fibre/epoxy materials composites with different ϕ were fabricated to be used as the sensing material in force sensor applications. The ring-shape composite with ϕ=0.5 was installed into a housing and the sensor was calibrated by different methods and its sensitivity was found to be 144 pC/N within the frequency range of 0.5–6.4 kHz which is much higher than that of a quartz force sensor with a similar structure. PACS 07.07.Df; 72.80.Tm; 77.84.Dy     

有序结构氟聚合物压电驻极体的制备和压电性研究

描述了一种有序微孔结构压电聚合物功能膜的制备方法,利用模板的高度有序实现薄膜微孔结构的精确控制.将此制备方法用于氟聚合物压电驻极体薄膜的制备,通过扫描电子显微镜(SEM)对其微观结构的观察表明薄膜具有理想的有序结构.对氟聚合物压电驻极体压电性的研究则是利用正压电效应测量准静态压电系数d₃₃,通过等温衰减和压强依赖性的测量考察其压电性能.结果表明:有序结构氟聚合物压电驻极体的准静态压电系数d₃₃可高达300 pC/N;与无序结构氟聚合物     

Physical foaming of fluorinated ethylene-propylene (FEP) copolymers in supercritical carbon dioxide: single-film fluoropolymer piezoelectrets

Cellular polymer foams with significant piezoelectric activity were prepared from fluorinated ethylene-propylene (FEP) copolymers. The required void structure is obtained by saturation of FEP films with supercritical carbon dioxide and a subsequent heat treatment for controlled inflation. After bipolar electric charging of the voids and evaporation of electrodes, the FEP films show piezoelectric d₃₃ coefficients up to 50 pC/N. The present physical foaming process generates cellular fluoropolymer piezoelectret films with usually only one single void across the film thickness. PACS 81.05.Rm; 77.65.-j; 77.84.Jd; 61.41.+e     

Effects of （LiCe） co-substitution on the structural and electrical properties of CaBi2Nb209 ceramics

The piezoelectric,dielectric,and ferroelectric properties of the(LiCe) co-substituted calcium bismuth niobate(CaBi2Nb2O9,CBNO) are investigated.The piezoelectric properties of CBNO ceramics are significantly enhanced and the dielectric loss tan δ decreased.This makes poling using(LiCe) co-substitution easier.The ceramics(where represents A-site Ca2+ vacancies,possess a pure layered structure phase and no other phases can be found.The Ca0.88(LiCe)0.04 0.04Bi2Nb2O9 ceramics possess optimal piezoelectric properties,with piezoelectric coefficient(d 33) and Curie temperature(TC) found to be 13.3 pC/N and 960 C,respectively.The dielectric and piezoelectric properties of the(LiCe) co-substituted CBNO ceramics exhibit very stable temperature behaviours.This demonstrates that the CBNO ceramics are a promising candidate for ultrahigh temperature applications.     

Properties of non-stoichiometric 0.935(K0.5+xNa0.5+x)NbO3-0.065LiSbO3 lead-free piezoelectric ceramics

0.935(K_0.5+xNa_0.5+x)NbO₃-0.065LiSbO₃ lead-free piezoelectric ceramics were prepared by normal sintering, and their piezoelectric and dielectric properties were investigated by varying the compensating amount x of alkaline elements (Na and K) addition. It was found that the crystal structure changed from tetragonal to orthorhombic with increasing x from −0.010 to 0.010. An MPB was tailored by optimizing the alkaline elements contents. Enhanced electrical and electromechanical responses of d₃₃=253 pC/N, k_p=0.47, k_t=0.45 and tanδ=0.027 were obtained in the ceramics with x=0.005. These excellent piezoelectric and electromechanical properties indicate that this system may be an attractive lead-free material for a wide range of electro-mechanical transducer applications.     

K0.5Na0.5NbO3-LiSbO3-BiFeO3/CuFe2O4复合陶瓷的制备与磁电性能研究

采用传统的固相法制备了(1-x)(K_0.5Na_0.5NbO₃-LiSbO₃-BiFeO₃)-xCuFe₂O₄ (x=0.1, 0.2, 0.3, 0.4) 磁电复合陶瓷, 并借助X射线衍射仪、扫描电镜和磁电耦合系数测试仪等对复合陶瓷的微结构和性能进行了分析. 结果表明, 复合陶瓷的K_0.5Na_0.5NbO₃-LiSbO₃-BiFeO₃和CuFe₂O₄物相之间发生了一定的离子相互扩散作用, 且两相的颗粒大小匹配性较好. 随着CuFe₂O₄含量增加, 复合陶瓷的压电系数从130 pC/N减小到30 pC/N, 饱和磁致伸缩系数从4.5×10^-6增加到12.4×10^-6左右, 磁电耦合系数表现出先增加后减小, 在x=0.3时获得最大的磁电耦合系数9.4 mV·cm^-1·Oe^-1. 关键词： 0.5Na_0.5NbO₃-LiSbO₃-BiFeO₃')" href="#">K_0.5Na_0.5NbO₃-LiSbO₃-BiFeO₃ 2O₄')" href="#">CuFe₂O₄ 磁电耦合