One-dimensional ZnO nanorods doped with neodymium for enhanced resorcinol degradation under sunlight irradiation

Neodymium-doped ZnO nanorods (Nd/ZNRs) were prepared for the first time by a simple and surfactant-free solvothermal route. The synthesized samples were characterized using different instrumental techniques. The photoluminescence results showed that the Nd(2.0 at%)/ZNRs exhibited the highest separation rate of charge carriers and the highest formation rate of hydroxyl radicals. The photocatalytic activities of synthesized samples were investigated toward the degradation of endocrine disrupting chemical resorcinol under natural sunlight irradiation. Among the samples, Nd(2.0 at%)/ZNRs showed considerable improvement in the photocatalytic activity for the resorcinol degradation as compared to ZNRs and commercial TiO₂. Kinetic studies revealed that the photocatalytic degradation of resorcinol obeyed pseudo-first-order kinetic. The high-performance liquid chromatography and total organic carbon analyses also demonstrated the progressive mineralization of resorcinol into carbon dioxide and water. Furthermore, high stability of Nd/ZNRs in photocatalytic reaction also demonstrated promising potential toward practical applications in purifying environmental pollutants.     

Effect of Eu3+-doping on morphology and fluorescent properties of neodymium vanadate nanorod-arrays

Tetragonal structural (t-NdVO₄) nanorod-arrays were fabricated by simple one-pot hydrothermal method. The phase, morphology and microstructure of NdVO₄ were characterized by X-ray diffractometer, scanning electron microscope (SEM), transmission electron microscope (TEM), dispersive X-ray spectrometer (EDS) and selected area electron diffraction (SAED) techniques. t-NdVO₄ nanorods are single-crystalline with a length of 100 nm and a diameter of 25 nm, which grow orientally along the direction of (112) crystalline plane and self-assemble to form nanorod-arrays. The results show that Eu³⁺-doping interrupts the formation of NdVO₄ nanorod-arrays, and then leads to the red-shift of the strongest luminescence emission of Nd³⁺ transition from ⁴D_3/2 state to ⁴I_11/2 and decreases its intensity of the fluorescence emission at 400 nm sharply. The research results have some reference values to optimize the photoluminescence performance of rare earth vanadates.     

Utilization of bio‐sourced myrcene for efficient preparation of highly cis‐1,4 regular elastomer via a neodymium catalyzed copolymerization strategy

The depletion of fossil based chemicals and the associated pollution have presented huge challenges to sustainability. In this study, we report on bio‐available myrcene participating in copolymerization with isoprene and butadiene by using neodymium catalysts without disruption of the pristine polymer's properties. Efficient incorporation of myrcene into the copolymer was achieved with slightly retarded reactivity compared to the reactivities of butadiene and isoprene. Copolymerization of myrcene with hydroxyl myrcene still remained compatible with the catalyst systems when the cocatalyst was fed in excess, resulting in a novel type of full myrcene based functional elastomer. The high cis‐1,4 selectivity of the system maintained the same level as the homopolymerization. Significant affinity to polar substances was deduced from the remarkably reduced water contact angle, a strong indication of good compatibility with reinforcing fillers. All copolymers displayed over 93.2% cis‐1,4 regularity and high molecular weight with narrow ?. Good resistance to low temperature was also achieved as indicated by the low glass transition temperature for all copolymers. This study verified that myrcene can be used as a sustainable monomer substituent for general diene based elastomer preparation. © 2020 Society of Chemical Industry     

Synergistic effect of polyindole decoration on bismuth neodymium ferrite powder for achieving wideband microwave absorber

Recently, composite materials with outstanding absorption properties, like extraordinary absorbing capability, light weight, and thin in size, are required to solve the challenges of electromagnetic pollution. In addition, most of the work is based on the optimization of absorber material structure, and microstructure. In the current work, we improved the reflection loss feature of Bi_0.5Nd_0.5FeO₃ nanopowders via decoration with polyindole polymer by tuning the filler loading of the nanocomposite in the matrix. XRD, UV–Vis, XPS, and FESEM were used to determine the physicochemical features of the as-prepared nanocomposite. The minimum RL was lowered further with the increasing filler loading at 25 wt%. The lower RL of ?22 dB was noticed for 2.2 mm thickness at 11.5 GHz. The maximum value of the SE_R for a 25 wt% sample was 5.5, whereas 19 dB and 24.5 dB values were recorded for SE_A and SET, respectively. The resonance peak above 11.5 GHz demonstrated the better outcome of the absorber at high frequency. Good impedance matching characteristics, conductive features, dielectrics, and magnetic losses were all credited with the excellent reflection loss and electromagnetic interference shielding efficiency. The as-prepared nanocomposite materials that have been proven are interesting prospects for electromagnetic reflection loss and interference shielding that is lightweight, flexible, and extremely effective.     

AI、Nb在Nd_2Fe_(14)B晶体中的价态及对其磁性的影响

本文研究了Al、Nb在Nd_2Fe_(14)B晶体中的价态及对其磁性的影响。结果表明:在Nd_2Fe_(14)B晶体中,具有较大结构体积的j_2晶位Fe原子[Fe(j_2)],由于受到近邻Nd的f电子的强烈作用,其d电子可以被“诱发”为磁电子,原子磁矩达3.4μ_B,比纯铁的2.4μ_B大得多;Nb原子在晶体中置换j_2、k_1、k_2晶位上Fe原子时,它的d电子也可能成为磁电子;Al和Nb原子在Nd_2Fe_(14)B晶体价电子结构中,以无晶格电子的价态置换有晶格电子的Fe原子价态,导致硬磁性相各向异性的增强;Nb的两个4d价电子参加晶体的键合,增强了材料的磁温度稳定性。     

Nd变质过共晶Al-17.5%Si合金的微观组织和断口形貌

采用单一稀土元素Nd对过共晶Al-17.5%Si合金进行变质;采用扫描电镜、金相显微镜、电子探针、透射电镜及X射线衍射等方法对变质前后合金的微观组织、成分和相组成进行分析;并对变质前后合金的断口形貌进行分析.结果表明:加入0.3%Nd(质量分数)到过共晶Al-17.5%Si合金中可同时变质初生硅和共晶硅,经过变质处理后,初生硅的形状由星形和不规则形状变为块状,尺寸由40～60 μm减小到10～30 μm,共晶硅由长针状变成球状或短棒状;初生硅区域的主要成分是硅,中心边缘几乎检测不到Nd元素,Nd沿晶界分布;与未变质合金相比,经0.3%Nd变质后的Al-17.5%Si合金硅相上孪晶密度增大,变质后的合金中没有生成新相,a(Al)相和硅相的晶格常数变大;经0.3%Nd变质后,合金的整体性能大幅度提高,抗拉强度提高了35.8%,从120 MPa提高到163 MPa,伸长率从0.8%提高到2.2%,提高了175%.     

添加稀土Nd改善金刚石/铜复合材料界面

目的添加稀土Nd改善金刚石/铜复合材料界面间的缺陷,抑制金刚石与铜之间的弱润湿性,增强复合材料的界面结合。方法采用放电等离子烧结(SPS)技术制备含有不同质量分数Nd的镀钛金刚石/铜复合材料,采用扫描电子显微镜观察界面处的微观形貌,采用X射线衍射仪和X射线能谱仪分析界面处组织,采用排水法测试复合材料的密度和致密度。结果添加稀土Nd后,金刚石-铜两相界面间促生了Cu_5Nd、NdCu_2、Cu_3Ti等相。界面间的Cu_5Nd、NdCu_2、Cu_3Ti、TiC填补了镀钛金刚石/铜复合材料界面处原有的空隙、孔洞等缺陷。未添加稀土Nd的镀钛金刚石/铜复合材料的密度为4.589 g/cm~3,致密度为81%;添加3wt%的Nd元素后,镀钛金刚石/铜复合材料的密度和致密度分别达到了5.569 g/cm~3和98%,密度较未添加Nd的复合材料提升了21%。随着Nd含量的增加,金刚石-铜界面间的缺陷逐渐减少,界面结合效果逐渐转好。结论稀土Nd极大地改善了镀钛金刚石/铜复合材料两相界面处的缺陷,很好地修饰了原本润湿性较差的金刚石-铜两相界面。添加Nd元素后,复合材料两相界面结合紧密。     

热压烧结掺钕钛酸盐组合矿物固化体及其浸出性能

以天然锆英石(ZrSiO4),CaCO3,TiO2,Nd2O3,Al2O3,SiO2为原料,采用真空热压烧结技术制备掺钕钙钛锆石和榍石组合矿物固化体,借助X射线衍射(XRD)、扫描电镜(SEM)、背散射(BSE)、电感耦合等离子体质谱(ICP-MS)等分析手段,研究了组合矿物固化体的热压烧结温度、相结构及浸出性能等。结果表明:组合矿物固化体的较佳热压烧结温度为1130~1170℃,固化体的相对密度≥97.2%,主要物相为钙钛锆石(CaZrTi2O7)和榍石(CaTiSiO5)的组合矿物;固化体具有良好的化学稳定性,在90℃,pH值为5,7,9的水溶液中,Nd3+在42天的归一化浸出率分别为1.9×10-6,1.5×10-6,1.2×10-6g·m-2·d-1;pH值对固化体中Ca2+,Zr4+的浸出率没有明显的影响;在弱碱水溶液(pH=9)中,Ti 4+,Nd3+的浸出率较低,Si 4+,Al 3+的浸出率较高。