共查询到20条相似文献，搜索用时 15 毫秒
1.
CsNiCl3晶体光谱、EPR谱和x散射实验的理论研究 总被引：4，自引：0，他引：4
采用半自洽场(semi-SCF)d轨道模型和完全对角化方法，对CsNiCl3晶体的吸收光谱，EPRg因子和零场分裂D和x散射实验作出了新的统一解释，计算结果与实验值符合得很好．在此基础上，进一步对CsNiCl3在低温下顺磁共振g因子随温度的漂移作了半定量的解释． 相似文献
2.
Abdul Aziz E. Ahme Muhammad Naeem Ashiq Muhammad Azhar Khan Nazia Karamat Irshad Ali 《自然科学进展(英文版)》2016,26(4):325-333
A series of Mn x Co_(1-x) Fe_(1-y) Nd_yO_3(where x=0.0–1.0 y=0.0–0.1) multiferroic nanocrystals was synthesized via sol-gel auto-combustion technique. The structure was confirmed by X-ray diffraction(XRD)while morphology was investigated by scanning electron microscopy(SEM). The electrical resistivity was observed to increase from 2.14 * 10~7 to 8.77 * 10~9 Ω-cm and activation energy was found to increase from 0.64 to 0.75 e V, while the drift mobility decreased from 4.75 * 10~(-13) to 1.27 * 10~(-15)cm~2V~(-1)S~(-1) by the substitution of Mn and Nd contents. The dielectric constant, dielectric loss and dielectric loss factor decrease with frequency and Mn-Nd contents. The saturation magnetization was increased from 34 to 70 emu g~(-1) while the coercivity decreased from 705 to 262 Oe with the increase of substituents.The increase in electrical resistivity and saturation magnetization while decrease in dielectric parameters and coercivity make these nanomaterials suitable for applications in microwave devices and longitudinal magnetic recording media. 相似文献
3.
A. Marikani V. Selvamurugan G. Mangamm S. Ravi R. Krishnasharm P.V. Chandrasekar M. Kamruddin D. Madhavan 《自然科学进展(英文版)》2016,26(6):528-532
This paper reports the synthesis of neodymium substituted bismuth titanate nanoparticles(BNdT) for ferroelectric random access memory(Fe RAM) based applications using sol-gel route. X-ray diffraction pattern showed that the BNdT nanoparticles exhibited perovskite structure with orthorhombic phase. The microstructure of the BNdT nanoparticles showed that the grains were in spherical structure with a bi-modal distribution of spheres. Dielectric constant and dielectric loss of BNdT nanoparticles were measured in the frequency range 100 Hz to 100 kHz. Nd-substituted BNdT nanoparticles showed the high remanent polarization(P_r=33.2 μC/cm~2, Ec=62.5 kV/cm) than pure bismuth titanate(BT)(P_r=14.6 μC/cm~2, Ec=182.8 kV/cm) ideal for FeRAM based applications. The occurrence of red shift in photoluminescence(PL) spectrum is considered to be due to the isomerisation that may occur from the heating of samples. 相似文献
4.
本文全面介绍了电流变材料的发展，包括电流变液、磁流变液和电磁流变液；此外还详细讨论了固相化学性质和添加剂与电流交响应的关系；指出了电流变材料的研究方向。作为这篇评论的结语概括介绍了电流变应用研究的最新成就。 相似文献
5.
Direct conversion of heat into electricity through advanced thermoelectric(TE)materials has been one of the most attractive solutions to the severe environmental and energy issues facing humanity.In recent years,great progress has been made in improving their dimensionless figure of merit(ZT),which determines the conversion efficiency of TE devices.ZT is related to three‘‘interlocked’’factors—the Seebeck coefficient,electrical conductivity,and thermal conductivity.These three factors are interdependent in bulk TE materials,and altering one changes the other two.The difficulty in simultaneously optimizing them caused TE research to stagnate,until great reductions in thermal conductivity were both theoretically and experimentally proven in nanomaterials in 1993.In this review,we first introduce some TE fundamentals and then review the most recently improvements in ZT in different kinds of inorganic and organic TE materials,which is followed by an investigation of the outlook for new directions in TE technology. 相似文献
6.
Controllable synthesis of Ni-catalyzed tetragonal tungstennanowires via chemical vapor deposition 相似文献
7.
SnO_2 NPs were successfully prepared via a hydrothermal method. X-ray diffraction analysis con fi rmed the rutile tetragonal structure of SnO_2 NPs. The crystallite size increased from 1.18 to 5.06 nm with increasing the preparation temperature from 100 to 180 °C. The SEM photography of the products exhibited the agglomeration of the SnO_2 nanocrystals to large view particles, while TEM images con fi rmed the polycrystalline phase and crystallite size those analyzed from XRD. The UV–vis absorption of ethanol suspended SnO_2 NPs was measured. The optical band-gap energies(Eg) were signi fi cantly blue-shifted due to quantum con fi nement. Fluorescence spectra came to con fi rm this shift, where a clear shift in the maximum emission peak was observed. Stokes shift of SnO_2 nanocrystals was found to be crystallite size dependent. 相似文献
8.
林玄鹤 《福州大学学报(自然科学版)》1987,(3):117-123
本文讨论两种气体在同一反应剂中同时进行化学吸收的过程,介绍以双膜模型作为分析问题 的基础,导出化学反应影响气体吸收速率的数学模型。同时指出该吸收过程的传质系数可用关联式 或直接取自实验数据。 相似文献
9.
机器人软体材料分为软体驱动材料和软体感知材料,在仿生机器人中分别起到效应器与感受器的作用。故在制造仿生机器人时,软体材料的开发越发重要。本文概述了机器人软体材料与软体机器人概念上的差异,按照软体驱动材料和软体感知材料分别综述了机器人软体材料的发展动态,并探讨了这两类重要的机器人软体材料研发方面挑战及趋势。 相似文献
10.
二氧化锡（SnO2）作为一种n型宽禁带半导体氧化物材料,广泛用于有机物催化、固态电子器件和锂离子电池电极材料领域。介孔SnO2具有较大的比表面积和纳米级有序孔道,与周围介质之间存在更强的相互作用力,可提高其在气敏传感器、催化反应中的应用效率。本文以SnCl4·5H2O为锡源,P123为模板剂,采用络合水热法合成了具有金红石结构的介孔二氧化锡,并考察了pH值、表面活性剂和添加剂等因素对介孔结构形成的影响;采用X射线衍射、透射电镜、荧光光谱等手段综合分析了产物的结构、形貌、成分及光学性质。结果表明所制备的介孔SnO2具有蠕虫状孔结构,表面积大,孔径集中分布在2～8 nm。合成的样品具有良好的光学性能,在光学材料领域具有应用前景。 相似文献
11.
吴俊杰;张颖;向斌 《中国科学技术大学学报》2023,53(10):1002-1-1002-12
Since topological quantum materials may possess interesting properties and promote the application of electronic devices, the search for new topological quantum materials has become the focus and frontier of condensed matter physics. Currently, it has been found that there are two interesting systems in topological quantum materials: topological superconducting materials and topological magnetic materials. Although research on these materials has made rapid progress, a systematic review of their synthesis, properties, and applications, particularly their synthesis, is still lacking. In this paper, we emphasize the experimental preparation of two typical topological quantum materials and then briefly introduce their potential physical properties and applications. Finally, we provide insights into current and future issues in the study of topological quantum material systems. 相似文献
12.
本文介绍了微波电子回旋共振等离子体气相沉积装置的磁场设计原理和计算方法,给出了几种电流强度、线圈间距等主要参量下的磁场形态. 相似文献
13.
使用水蒸气蒸馏法对＂三子汤＂中的挥发油进行提取,通过气相色谱-质谱联用技术对＂三子汤＂化学成分进行分离鉴定,采用色谱峰面积归一化法确定各成分的相对含量.分析结果表明,共检测出60种个组分,鉴定了其中的27个组分.主要成分是3-呋喃甲醛、己酸、左旋樟脑、β-环柠檬醛、2,3-二氢-2,2,6-三甲基苯甲醛、己醛. 相似文献
14.
Bi_(2/3)Cu_3Ti_4O_(12)(BCTO) ceramic was synthesized by the semi-wet route using metal nitrate solutions and solid TiO_2 powder in a stoichiometric ratio. Fourier transform infrared(FTIR) study of BCTO precursor powder and calcined ceramic showed the presence of alcoholic functional groups and the stretching band of Ti-O and Cu-O respectively. X-ray diffraction(XRD), scanning electron microscope(SEM) and energy dispersive x-ray spectroscopy(EDX) were employed to characterize the structure, surface morphology and purity of the sintered BCTO ceramic respectively. X-ray diffraction study confirmed the single phase formation of BCTO ceramic at1073 K. The average dimension of grains calculated by SEM and AFM was found to be in the range of 0.73 ±0.2 μm with clear grain boundaries. Magnetic property was investigated over a wide temperature range 2–300 K at a magnetic field of 7 tesla. The Curie temperature was calculated by zero field cooled(M~(ZFC)) and field cooled(M~(FC)) magnetization at 100 Oe applied field which was found to be 125 K. The sintered BCTO ceramic shows high dielectric constant(ε'=2.9×10~4) at 323 K and 100 Hz. 相似文献
15.
16.
多孔性甲基丙烯酸树脂的合成及葡萄糖淀粉酶的固定化 总被引：1，自引：0，他引：1
用悬浮聚合法合成了多孔性甲基丙烯酸树脂。用此载体比较了保护戊二醛法，重氮化法和叠氮法固定化葡萄糖淀粉酶的效果，并研究了二乙醇胺保护戊二醛活化载体，树脂多孔结构多数及不同悬臂长度等方面对固定化葡萄糖淀粉酶活力的影响。结果表明，用保护戊二醛法活化的树脂固定化酶效果较好。当戊二醛与二乙醇胺为４∶１（摩尔比），树脂孔径为５５２．１，比表面为２８．３ｍ￣２／ｇ孔容为０．６３５ｃｍ￣３／ｇ时，固定化酶的相对活力为５５．６％，而酶活回收率为２４．７％。 相似文献
17.
18.
由于社会需求紧迫,金属氧化物半导体纳米气敏材料成为当今研究的热点。本文综述了从材料元素的组成、形貌及尺寸的控制以及制备方法等方面来提高金属氧化物半导体纳米材料气敏性能的研究进展。 相似文献
19.
综述了近年来常用荧光素类荧光材料的合成方法,包括傅克酰基化反应、缩合反应和利用格氏试剂的合成反应,对目前研究比较活跃和应用比较广泛的几种荧光素类荧光材料的性质进行了系统分析. 相似文献
20.
本文研究了磁处理对油体系流变性质和结蜡性质的影响。实验证实磁处理可以使油体系的流性指数增加和稠度系数减少,说明磁处理有利于改善油体系的流动性能,最佳的磁感应强度为30～60mT。研究表明,磁处理虽然能加强含蜡煤油的结蜡倾向,但可减少原油的结蜡倾向。影响结蜡倾向的最强的磁感应强度为100mT。本文首次提出用温度指数对比油体系的结蜡倾向。 相似文献