镍铁氧体/聚苯胺复合材料的制备及其性能

采用超声场下原位聚合法制备镍铁氧体/聚苯胺复合材料,并采用x射线衍射仪(XRD)和HP8510网络分析仪研究其结构和电磁性能.结果表明:十二烷基苯磺酸(DBSA)掺杂后的聚苯胺是部分结晶的,镍铁氧体与聚苯胺分子链之间存在某些相瓦作用;与聚苯胺相比,镍铁氧体/聚苯胺复合材料的介电损耗角正切值tanδ<,ε>与磁损耗角正切值tanδ<,m>都增大;镍铁氧体含量为5%和15%(质量分数)的复合材料分别具有最大的tanδ<,ε>暝值和最大tanδ<,m>值;镍铁氧体含量为15%的试样在8～18 GHz范围内综合吸波性能最好,具有最大衰减-23.4 dB,-8 dB带宽为5.73 GHz.     

聚苯胺纳米线复合材料的制备与储能性分析

针对软、硬模板法制备纳米线的缺陷,提出一种步骤简单、快速且低成本的方法来获得直径均匀的PANI纳米线复合材料,并对所制备出的PANI纳米线复合材料进行表征和电化学性能研究。首先,采用阳极氧化剥离法,分别在硝酸体系、磷酸还原体系及硫酸体系中对表面光滑的石墨板进行电化学剥离处理。随后,在经过电化学剥离后的粗糙石墨表面上进行电聚合,从而得到PANI纳米线复合材料。表征分析发现,经电化学剥离处理的石墨纸表面分别生成具有大量活性点的石墨烯和氧化石墨烯,与PANI结合显著提高了PANI的导电性。其中硝酸体系制备的聚苯胺复合材料(PANI/GO)微观为纳米线组成的三维网状结构;磷酸还原体系制备的聚苯胺复合材料(PANI/GR1)微观是纳米线和纳米片层混合结构;硫酸体系制备的聚苯胺复合材料(PANI/GR2)的微观结构介于二者之间。以镁合金和上述三种PANI复合材料为电极,制备出简易的海水电池。使其在电流密度为3.75 m A·cm^-2下放电至0.9 V时止。三种电池的比能量分别为540、228和363 m Wh·g^-1,结果表明PANI/GO的储能性最优。...     

高能球磨法制备LiFe_5O_8/PANI纳米复合材料及其吸波特性

利用溶胶-凝胶自蔓延燃烧法制备LiFe5O8铁氧体纳米粉末,采用化学方法合成盐酸(HCl)掺杂的聚苯胺(PANI)粉末,利用高能球磨法制备LiFe5O8/PANI纳米复合材料,用XRD、VSM及微波矢量网络分析仪对样品进行表征。结果表明,制备的LiFe5O8/PANI复合材料生成了某种顺磁性物质和少量的Fe2O3。与单纯的LiFe5O8铁氧体纳米材料相比,LiFe5O8/PANI复合材料的介电损耗和磁损耗均有上升,共振吸收峰也明显展宽和增高。     

多壁碳纳米管/双马来酰亚胺树脂复合材料的制备及其电磁性能

采用化学气相沉积(CVD)法,在1000℃、氮气保护气氛下,制备了铁-钴-镍混合粉末掺杂的多壁碳纳米管(m-MWCNTs,m=Fe-Co-Ni)。再以m-MWCNTs作为吸波剂,双马来酰亚胺(BMI)树脂为基体,制备出m-MWCNTs/BMI复合吸波材料。使用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、矢量网络分析仪等对复合材料的微观结构和电磁性能进行表征和测试分析。结果表明,m-MWCNTs作为吸波剂,对电磁波既有介电损耗,也有较强的磁损耗;在2~18 GHz频率范围内,当m-MWCNTs质量分数为8%时,2 mm厚度复合材料的电磁反射损耗在频率为12.96 GHz处达到–12.63d B,频率带宽(低于–5d B)达到5.2 GHz,表明m-MWCNTs/BMI复合吸波材料具有良好的电磁参数匹配特性。     

纳米铁氧体复合材料制备及吸波性能研究

采用溶胶-凝胶与自蔓延燃烧相结合的方法制备出碳．纳米铁氧体复合材料，应用X射线衍射仪、扫描电镜分别对产物的晶体结构和微观形貌进行了表征分析，着重对比研究了超细碳材料加入前后的变化。利用小型烟箱试验测出产物在军用红外波段质量消光系数大于1．1m^2／g；利用矢量网络分析仪测试其在2～18GHz的电磁参数，并得到损耗角正切值随频率变化的曲线。结果表明：在纳米铁氧体中添加超细碳材料，铁氧体原有的磁损耗不变，介电损耗值有了显著提高，从而增加了电磁波的总损耗。由此证实超细碳-纳米铁氧体复合材料具有宽频吸波特性。     

镧六角晶系铁氧体Ba0.8La0.2(Zn0.5Ni0.5)2-xCoxFe15O27的制备及电磁性能

用柠檬酸溶胶-凝胶法制备了铁氧体Ba0.8La0.2(Zn0.5Ni0.5)2-xCoxFe15O27(x=0.8,1.0,1.2,1.4).采用X射线衍射(XRD)分析,扫描电镜(SEM),热重(TG)和差热分析(DTA)对凝胶及铁氧体的晶型和显微结构进行了研究,并用网络分析仪测试了样品在2～18 GHz范围内的的电磁参数.研究发现制备的铁氧体是片状的W型晶体,随着Co2 含量的增多,铁氧体中M晶型的含量逐渐增多;当x为1.0时,铁氧体的损耗角正切达到最大值0.57.     

Al薄膜对玻璃纤维增强树脂基复合材料电磁性能的影响

利用高频电磁场计算软件FEKO对Al薄膜与玻璃纤维增强树脂基复合材料的电磁波反射率进行了仿真计算。研究了复合材料介电常数实部er、电损耗角正切tande、磁导率mr及磁损耗角正切tandm对反射率的影响,并通过仿真计算与实际测试结果对比,确定了仿真模型中玻璃纤维增强树脂基复合材料的等效电磁参数。研究了Al薄膜与玻璃纤维增强树脂基复合材料结构中Al薄膜厚度对反射率的影响,仿真计算与测试结果表明,Al薄膜厚度对复合材料的反射率影响较大,Al薄膜与玻璃纤维增强树脂基复合材料结构中存在一个最佳电阻值,使该结构谐振反射最小。根据传输线理论,利用MATLAB对谐振最强时对应电阻的大小进行了求解。通过计算不同结构的Al薄膜与玻璃纤维增强树脂基复合材料,得到了仿真模型中Al薄膜与磁控溅射制备Al薄膜的厚度关系。确定了仿真模型中各材料的等效电磁参数,仿真计算结果与测试结果吻合较好。     

镍铜铁氧体纳米粉的磁性与介电性能

用溶胶-凝胶制备了系列Ni_(0.5)Cu_(0.5)Fe_2O_4铁氧体微粉。采用扫描电子显微镜、X射线衍射仪、振动样品磁强计和网络矢量分析仪对粉末的形貌、结构、磁性以及介电性能进行了表征。结构表明,反应温度为40℃,前驱体在1000℃煅烧转变成纯尖晶石结构。三粉末样品在室温和低温都具有铁磁特性,而且出现交换偏置效应。纯尖晶石结构样品3的电磁损耗角正切值tanδ在2~6.5 GHz范围内随频率的增大而增大,以后逐渐减小。     

纺锤状ZnO/还原氧化石墨烯异质结构及其微波吸收性能

目的调节石墨烯的电磁匹配,以实现最优的微波吸收性能。方法通过改进的Hummers法制备氧化石墨烯GO,以六水合硝酸锌、双六甲撑三胺、氧化石墨烯为原料,采用水热法在140℃获得了具有异质结构的包裹r-GO的纺锤状ZnO棒(S-ZnO/r-GO)。通过X射线衍射分析仪(XRD)、扫描电子显微镜(SEM)以及透射电子显微镜(TEM)测试,分别对S-ZnO/r-GO的组成成分、形貌特征以及微观结构进行了表征,同时采用同轴法,通过矢量网络分析仪测试分析了不同填充浓度下S-ZnO/r-GO复合材料在2~18 GHz范围内的电磁特性,并通过计算得到了材料的微波反射率损耗。结果尺寸均匀且相互交织的纺锤状ZnO棒被大量褶皱的还原氧化石墨烯所包覆,构建了一种相互连接的三维交织结构。纺锤状ZnO的引入以及三维结构的建立,明显改善了S-ZnO/r-GO异质结构在2~18 GHz频率范围内的电磁特性和微波响应。在厚度为2.0 mm,频率为14.8 GHz处,最大反射率损耗值达到−40 dB,有效吸收带宽几乎覆盖整个Ku波段。结论纺锤状ZnO/r-GO复合材料表现出优异的微波吸收性能和较宽的有效吸收频段,具有一定的应用前景。     

PANI/Ag-TiO2纳米纤维复合材料的制备及其抗菌性能研究

采用水热法制备Ag掺杂量不同的Ag/TiO2纳米复合材料,通过原位聚合法制备PANI/Ag-TiO2纳米纤维复合材料,利用XRD、SEM、FT-IR等检测技术对复合材料的结构进行了表征。研究了光源、Ag掺杂量、不同实验菌种等因素对PANI/Ag-TiO2纳米纤维复合材料抗菌性能的影响。结果表明：在无光照射情况下,PANI/Ag-TiO2纳米纤维复合材料具有良好的抗菌性能,在长波紫外光照射情况下,抗菌性能进一步增强。在浓度1 mg/mL时,在无需光照的情况下对4种实验菌种杀菌率均达到99.99%。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.