钛酸钡掺杂镧陶瓷的电学性质研究

许多文献报道,在钛酸钡陶瓷中掺入稀土多酸微量元素（0.1-0.3%）,会使钛酸钡陶瓷的电阻率降低[1][2][3]。将钛酸钡掺杂镧陶瓷阻抗谱和纯钛酸钡陶瓷阻抗谱相比较,发现掺入量为0.02%时的阻抗谱和钛酸钡陶瓷阻抗谱形状大体一致,可以认为具有相同的物理过程。而当掺入量为0.01%时,图谱的形状发生了变化。据此,我们采用溶胶-凝胶法制备钛酸钡及掺杂镧的钛酸钡纳米晶;利用交流阻抗谱测试其电学性质;主要对钛酸钡系电子陶瓷的晶粒电阻进行了更深的研究和探讨,分析掺镧0.01%碳酸钡陶瓷阻抗谱,得出样品阻抗谱所对应的最佳等效电路和参数值。     

PTC在现代家用电器中的应用

PTC（Positive Temperature Coefficient）元件是以钛酸钡（BaTio_s）为主体材料掺合微量的稀土元素经研磨、压型、高温烧结而成的一种N型半导体敏感器件。它的基本特性如图1所示。     

水热合成镍掺杂钛酸钡及应用研究

钛酸钡作为典型的铁电材料，在光催化剂降解水中有害物领域有较大的应用潜力。本课题以镍掺杂钛酸钡为研究体系，探究镍掺杂对光催化性能的影响。实验结果表明，以钛酸四丁酯为钛源，氯化钡为钡源，钡镍比7∶3、加入12 mL NaOH和4 mL乙醇，反应24 h为最优条件，其光催化降解率为88.84%。并通过XRD、固体荧光、紫外可见漫反射谱图，分析镍掺杂钛酸钡光催化性能的原理。     

BaTiO3/聚氨酯纳米复合物弹性体的制备与电致伸缩性能

以聚酯二元醇、甲苯二异氰酸酯、1,4丁二醇、1,1,1三羟甲基丙烷和纳米钛酸钡粉体为原料,采用一步法制备了一系列BaTiO3/聚氨酯复合物弹性体.BaTiO3/聚氨酯复合物弹性体的密度、硬度和介电常数随钛酸钡含量的增加而增加.采用数字散斑相关测量方法研究了复合物弹性体在电场诱导下的应变与复合物中钛酸钡含量的关系.结果表明BaTiO3/聚氨酯复合物弹性体在外加高压电场的作用下,随着高压电源的开合,其应变也随之呈现出相应的收缩与回复.复合物的电致伸缩系数高于相应的聚氨酯弹性体,但复合物的电致伸缩系数随复合物中钛酸钡含量的增加而逐渐减小.     

浅谈电热灭蚊器的原理

题目 家用电热灭蚊器中电热部分的主要元件是PTC．PTC元件是由钛酸钡等半导体材料制成的电阻器，其电阻率与温度的关系如图1所示，由于这种特性，因此，PTC元件具有发热、控温双重功能．对此，以下判断中正确的是[ ]     

钛酸钡纳米晶的Sol-gel法制备及其表征

采用溶胶－凝胶工艺制备了立方相钙钛酸钡纳米晶，用TG－DTA对凝胶进行热分析，用XRD，TEM，DSC及Raman研究了样品的晶粒大小及结构。结果显示：钙钛矿钛酸钡晶化温度为750℃，平均粒径21nm，形状近似球型，Raman光谱中软模E（TO2＋LO）对应的拉曼峰消失，在室温下以立方相为主要存在相，结构相变具有有序－－无序特征。     

BaTiO3铁电相变的拉曼光谱研究

通过对近几年来钛酸钡(BaTiO3)的高温、高压、尺寸效应以及掺杂体系的Raman光谱的研究成果的总结，章对铁电相变的有序-无序相变的理论模型给与肯定。认为尽管引起钛酸钡铁电相变的机制各不相同，但均与应力有关，应力的作用致使有序度降低，从而导致软模解冻，发生铁电相变。     

相对介电常数测试与模拟计算结合研究

采用频率谐振实验和第一性原理计算方法分别测试和计算了钛酸钡相对介电常数随频率的变化关系。谐振法测试结果表明,在100Hz~10kHz频率范围内,钛酸钡相对介电常数随频率从1 250下降到150。第一性原理计算结果显示,光频下该材料相对介电常数数值较小且存在色散现象。两种方式对比研究有助于学生深入理解电介质相关极化理论。     

兔儿伞染色体的核型分析

对兔儿伞体细胞染色体计数。并对其棱型进行分析,结果表明：兔儿伞的染色体数目为2n：52;棱型公式为2n=2x=52=34m＋18sm;棱型不对称系数为59．10％;属于2B型．     

高纯超细钛化合物醇——碳酸盐法联产工艺探讨

高纯超细二氧化钛、钛酸铅、钛酸钡、钛酸锶等是生产高性能电子元件的重要原料,其被广泛用于高温敏感电子元件(高温PTC)、压电陶瓷、结构陶瓷的生产上。在现阶段．钛化合物生产厂家几乎都是生产单一品。笔把醇盐法和碳酸盐法结合起来以对多种钛化合物的生产进行实验性研究。并对多种钛化合物的生产工艺进行探讨。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.