(Li_(0.5)Fe_(0.5))_(0.7-y)Zn_(0.3)C_(oy)Fe_2O_4铁氧体磁性的研究

在Li－Zn铁氧体（Li0.5Fe0.5）0.7ZnFe2O4基础上,用Co2 离子代换其中的（Li Fe3 ）0.5离子,研究了（Li0.5Fe0．5）0.7－yZn0.3CoyFe2O4（y＝0．00;0．005;0．01;0．02;0．03）铁氧体磁性与Co2 离子代换换量y之间的关系,结果表明：随着Co2 离子代换量的增大,晶格常数增大,而气隙率及居里温度减小,当代换量y＜0．005时,饱和磁性极化强度增大。     

稀土Y2O3和Gd2O3共掺杂对La2 (Zr0.7Ce0.3)2O7陶瓷相结构及热膨胀系数的影响

采用固相合成法制备了(La1-2xYxGdx)2(Zr0.7Ce0.3)2O7(x=0,0.30,0.35,0.40,0.45,0.50)体系陶瓷材料.分别利用XRD、扫描电子显微镜和高温热膨胀仪对陶瓷材料的相组成、微观形貌及热膨胀系数进行测试.结果表明.掺杂量x=0时为立方烧绿石结构,x≥0.30时为立方萤1石结构;晶粒发育良好,晶界清晰;Y2O3和Gd2O3的掺杂可以有效的提高La2 (Zr0.7 Ce0.3)2O7的热膨胀系数.     

Co_(0.5)Zn_(0.5)Fe_2O_4/C复合物的制备及电磁性能研究

采用水热法制备出不同比的Co0.5Zn0.5Fe2O4/C复合物,通过X射线衍射分析仪(XRD)、扫描电镜(SEM)、能谱仪(EDS)、振动样品磁强计(VSM)、网络分析仪对该复合物的形貌、电磁性能进行表征与分析。结果表明:Co0.5Zn0.5Fe2O4被碳包裹程度随碳相对含量的增加而增加;在频率为3~18 GHz范围内,Co0.5Zn0.5Fe2O4/C复合物的介电常数虚部和介电损耗随Co0.5Zn0.5Fe2O4的相对含量增加而增加;与Co0.5Zn0.5Fe2O4相比,Co0.5Zn0.5Fe2O4/C复合物的最大吸收峰有明显提高,且当0.5 g Co0.5Zn0.5Fe2O4与2 g葡萄糖混合时,制备的样品最大吸收峰在频率16 GHz左右可达到7 d B。     

LiNi_(0.5)Mn_(1.5)O_4正极材料的γ-Al_2O_3包覆及其性能

以氢氧化铝溶胶为前驱体在Li Ni0.5Mn1.5O4正极材料表面制备尖晶石结构γ-Al2O3包覆层,借助XRD、SEM、TEM及电化学方法对电极材料的主要性能进行了研究。结果表明:Li Ni0.5Mn1.5O4表面γ-Al2O3包覆层形成条件为600℃下煅烧0.5 h,较佳包覆量约为3%(摩尔比);γ-Al2O3包覆层形貌完整,厚度约为5~10 nm,(311)晶面间距约0.24 nm;γ-Al2O3包覆的Li Ni0.5Mn1.5O4正极材料30周充放电循环(0.2 C)后的比容量为112.1 m Ah/g,4 C倍率下的比容量为82.0 m Ah/g,容量保持率较基体分别提高了约10%和17.2%。因此,γ-Al2O3包覆层减小了Li Ni0.5Mn1.5O4与电解液的接触,有效抑制了基体与电解液之间的副反应,其电化学反应可逆性、循环稳定性及倍率性能得到了提高,有望用作动力锂离子电池正极材料。     

Na2SO4·0.5H2O2·H2O的热分解动力学研究

采用程序升温法研究Na2SO4.0.5H2O2.H2O在氮气中的热分解动力学,测定Na2SO4.0.5H2O2.H2O分解的TG-DTG和TG-DSC曲线.在8.0 K.min-1、6.1 K.min-1、4.1 K.min-1和2.0 K.min-14个升温速率下,Na2SO4.0.5H2O2.H2O的热分解是简单的一步反应,热分解温度为339.5 K.采用多元非线性回归对Na2SO4.0.5H2O2.H2O在氮气中的热分解动力学模型进行筛选,并利用主曲线法对其分解模型进行判别.Na2SO4.0.5H2O2.H2O的热分解过程受三维相界面控制,分解机理为R3机理.Na2SO4.0.5H2O2.H2O的热分解活化能为70.83 KJ.mol-1,指前因子1.96×103.     

Pt负载Li2Co2O4的合成及其析氧性能研究

氢气作为清洁燃料在未来的能源版图中将发挥重要作用。电解水制氢反应只生成氢气和氧气,具有成本低、效率高、环境友好、安全性好等优点,而析氧反应是电解水制氢中的一个关键控速反应步骤。介绍了一种简单的Pt负载Li₂Co₂O₄合成方法,并对其析氧性能进行了表征。调控不同的Pt负载量（质量分数）,比较对电催化性能的影响,最后得到Pt负载量5%为最优负载量。通过X射线衍射（XRD）、透射电子显微镜（TEM）对材料的结构进行表征,结果表明,得到了一种在保持催化剂的活性与耐久性的同时能够减少Pt消耗的高效催化剂。     

2-(2-羟基-4-氨基苯基)氢化苯并三唑的合成研究

2－（2－羟基－4－氨基苯基）氢化苯并三唑是新型活性紫外线吸收剂的一个重要中间体。以邻硝基苯胺和间氨基酚为原料，经重氮化、偶合、还原制备了2－（2－羟基－4－氨基苯基）氢化苯并三唑，产率为89％。研究重氮化反应及偶合反应的影响因素，得出适宜的反应条件。     

Single-negative properties of Ba2Co1.8Cuo.2Fe12O22 and Ba3Co2Fe23.4Zn0.6O41 hexagonal ferrites

The electromagnetic properties of Ba2Co1.8Cu0.2Fe12O22 (Co2Y) and Ba3Co2Fe23.4Zn0.6O41 (Co2Z) were studied by measuring microwave scattering parameters.In the transmission spectra of Ba2Co1.8Cu0.2Fe12O22,a forbidden band emerges due to ferromagnetic resonance,and the permeability will turn to negative in the vicinity of the ferromagnetic resonance frequency.In the complex permittivity spectra of Ba3Co2Fe23.4Zn0.6O41,the negative permittivity can be obtained due to dielectric resonance.Therefore,Co2Y and Co2Z can be used to construct left-handed materials possessing negative permeability and negative permittivity simultaneously.     

Single-negative properties of Ba_2Co_（1.8）Cu_（0.2）Fe_（12）O_（22） and Ba_3Co_2Fe_（23.4）Zn_（0.6）O_（41） hexagonal ferrites

The electromagnetic properties of Ba2Co1.8Cu0.2Fe12O22 (Co2Y) and Ba3Co2Fe23.4Zn0.6O41 (Co2Z) were studied by measuring microwave scattering parameters.In the transmission spectra of Ba2Co1.8Cu0.2Fe12O22,a forbidden band emerges due to ferromagnetic resonance,and the permeability will turn to negative in the vicinity of the ferromagnetic resonance frequency.In the complex permittivity spectra of Ba3Co2Fe23.4Zn0.6O41,the negative permittivity can be obtained due to dielectric resonance.Therefore,Co2Y and Co2...     

聚苯胺/碳纳米管/Ni0.5Zn0.5Fe2O4制备及其磁性能

利用原位聚合法制备纳米电磁复合材料聚苯胺包覆碳纳米管(MWNT)/Ni0.5Zn0.5Fe2O4.采用XRD、TEM、HRTEM、FTIR、TG-DSC和VSM等方法对复合材料进行表征,XRD结果表明,聚苯胺、碳纳米管和Ni0.5Zn0.5Fe2O4共存于复合材料;TEM结果表明,PAn包覆在MWNT/Ni0.5Zn0.5Fe2O4外表面,包覆厚度为15～30 nm;TG-DSC及磁性研究表明,复合材料的矫顽力为21 687.02 A/m,饱和磁化强度为2.27 T,是一种具有较好磁性能的软磁材料.     

Zr1-xHfxW2O8 (x=0,0.3,0.5,0.7,0.8,1.0)的合成及负热膨胀特性的研究

采用固相化学反应的方法 ,成功合成了立方结构的Zr1 -xHfxW2 O8(x =0 ,0 .3,0 .5 ,0 .7,0 .8,1 .0 )系列材料 .高、低温X射线衍射分析表明 ,Hf4+替代Zr4+对Zr1 -xHfxW2 O8的负热膨胀系数影响不大 .在 373K～ 973K温度范围 ,Zr1 -xHfxW2 O8线膨胀系数αl 约为 - 6× 1 0 - 6K- 1 ;在83K～ 2 98K温度范围Zr0 .5Hf0 .5W2 O8的αl =- 9.6× 1 0 - 6K- 1 .     

Microwave Synthesis of Cathode Material LixMn2O4 for Lithium-ion Battery

LixMn2O4 was synthesized rapidly by microwa heaing,the product phases of the microwave synthesis and comventional solid-solid-state synthesis were comparatively inesitigated,The capacity of microwave synthesis product decreases relatively slow,The lithium ion can be inserted into and extracted from the spinel framework structure fluently after cycling .But the capacity of the conventional solid-state synthesis product is more remarkably lowered.The spinel framework structure was destroyed which hindered the lithium ion from inserting and extracting,Tehe influential factors of the process parameters are discussed such as heat preservation time,pre-heating at 400℃ for 24 h and coupled agent.     

Direct Synthesis of Al_2O_3-modified Li(Ni_(0.5)Co_(0.2)Mn_(0.3))O_2 Cathode Materials for Lithium Ion Batteries

To improve the cyclic stability at high temperature and thermal stability, the spherical Al_2O_3-modified Li(Ni_(0.5)Co_(0.2)Mn_(0.3))O_2 was synthesized by a modified co-precipitation method, and the physical and electrochemical properties were studied. The TEM images showed that Li(Ni_(0.5)Co_(0.2)Mn_(0.3))O_2 was modified successfully with nano-Al_2O_3. The discharge capacity retention of Al_2O_3-modified Li(Ni_(0.5)Co_(0.2)Mn_(0.3))O_2 maintained about 99% after 200 cycles at high temperature(55 ℃), while that of the bare one was only 86%. Also, unlike bare Li(Ni_(0.5)Co_(0.2)Mn_(0.3))O_2, the Al_2O_3-modified material cathode exhibited good thermal stability.     

超声珩磨复杂声学系统的局部共振机理研究(Ⅱ)

将超声珩磨复杂声学系统中的各元件作为 1个整体来分析其振动的频率方程 ,是十分困难的 .根据局部共振原理 ,对超声珩磨复杂声学系统中的挠性杆 -油石座振动子系统的振动特性进行了理论与试验研究 ,研究结果对超声珩磨声学系统各元件的设计与制造及提高缸筒类零件表面质量有一定的参考价值     

钨磷杂多阴离子〔(P_4W_(30)Cu_4(H_2O)_2O_(112))~(16-)〕合成方法的改进及其配位水的取代反应

介绍了标题杂多阴离子改进的实验方法及其配位水的取代反应。通过控制溶液ｐＨ值的方法得到的标题杂多阴离子产品转化率增加，纯度高。配体取代配位水的反应在水溶液中不能发生，而在非极性有机溶剂中配位水分子易脱去形成配位不饱和态〔１〕，此反应却容易发生。