Preparation and electromagnetic property of Al-doped SnO2 powders by coprecipitation method in the GHz range

Al-doped SnO₂ powders have been prepared by coprecipitation method at 550 °C, using tin chloride (SnCl₄·5H₂O) as the raw material, ammonium hydroxide (NH₃·H₂O) as the precipitator, and aluminum nitrate (Al(NO₃)₃·9H₂O) as the doping source, respectively. The microstructure of the prepared powders has been characterized by X-ray diffraction and scanning electron microscope, respectively. Results show that the prepared powders were Sn_(1?x)Al_xO₂ (x = 0, 0.03, 0.06, and 0.09) solid solution powders and the lattice constant decreased with increasing Al doping content. The electromagnetic property in the frequency range of 8.2–12.4 GHz of prepared powders has been determined. The real part (ε′) and imaginary part (ε″) of permittivity of prepared powders increased with increasing Al doping content. There was little change of real part (μ′) and imaginary part (μ″) of permeability of prepared powders. The electromagnetic loss mechanism has been discussed.     

第一原理研究Zr元素对UO2结构与力学性能的影响

本文采用第一性原理密度泛函理论研究了Zr元素对UO2结构与力学性能的影响。计算结果表明,随着Zr元素含量的增加,UO2的晶格参数、晶胞体积均逐渐减小。其中,掺杂形成能,U-O键,Zr-O键和O-O键的单位键长随着Zr元素的增加而降低。通过计算其弹性模量,发现Zr含量在20wt%前,随着Zr含量的增加,UO2的体模量略微增大,而剪切模量略微降低;当Zr的含量达到40wt%时,UO2体模量随着Zr含量的增加而明显增大,剪切模量反而增大。同时,随着Zr含量的增加,UO2的B/G值不断增加,材料呈脆性向塑性转变的趋势。     

Bimetallic Pd-Ni core-shell nanoparticles as effective catalysts for the Suzuki reaction

A simple and efficient solution-based method for the synthesis of Pd-Ni bimetallic nanoparticles （NPs） has been developed. A series of Pd-Ni bimetallic NPs were readily achieved by reduction of PdC12 and Ni（acac）2 （acac = acetyl- acetonate） in the presence of oleylamine （OAm）, oleic acid （OA） and benzyl alcohol. Furthermore, by using high-resolution transmission electron microscopy （HRTEM）, energy-dispersive spectrometry （EDS） mapping and X-ray diffraction （XRD）, we demonstrate that the as-prepared Pd-Ni bimetallic NPs have core-shell structures with a Pd-rich core and a Ni-rich shell. In addition, the as-obtained Pd-Ni bimetallic NPs with varying compositions show excellent catalytic activities in the Miyaura-Suzuki reaction. When the nickel molar percentage was 0.23 to 0.65, the conversion with the as-obtained Pd-Ni bimetallic catalysts was above 90%. It is believed that this strategy can be employed to produce a variety of other well-defined core-shell type multimetallic nanostructures.     

A Multifunctional Nanoplatform for Imaging,Radiotherapy, and the Prediction of Therapeutic Response

Gold nanoparticles have garnered interest as both radiosensitzers and computed tomography (CT) contrast agents. However, the extremely high concentrations of gold required to generate CT contrast is far beyond that needed for meaningful radiosensitization, which limits their use as combined therapeutic–diagnostic (theranostic) agents. To establish a theranostic nanoplatform with well‐aligned radiotherapeutic and diagnostic properties for better integration into standard radiation therapy practice, a gold‐ and superparamagnetic iron oxide nanoparticle (SPION)‐loaded micelle (GSM) is developed. Intravenous injection of GSMs into tumor‐bearing mice led to selective tumoral accumulation, enabling magnetic resonance (MR) imaging of tumor margins. Subsequent irradiation leads to a 90‐day survival of 71% in GSM‐treated mice, compared with 25% for irradiation‐only mice. Furthermore, measurements of the GSM‐enhanced MR contrast are highly predictive of tumor response. Therefore, GSMs may not only guide and enhance the efficacy of radiation therapy, but may allow patients to be managed more effectively.     

Fe-Co合金磁滞性能温度特性研究

2J4合金为Fe-Co磁滞合金,具有较好的磁滞性能,在航空航天上广泛应用磁滞电机和导航陀螺仪以及直流电动机及继电器等部件。研究了2J4合金磁滞性能温度特性,对合金进行回火处理和冷处理。结果表明,试样回火处理后,内部位错降低,磁畴取向度加强,数目增多,合金内有大量富V、Ni析出相,在磁化时,对磁壁钉扎作用增强,导致材料的剩磁、矫顽力、磁滞损耗增加;冷处理后材料体积收缩、致密度增加、内应力增加,导致合金饱和磁感应强度、剩磁、矫顽力、磁滞损耗增加,可为制造高性能磁滞电机选用磁滞合金材料提供参考。     

基于极限学习机的爆破参数综合优选

为了合理选择川口钨矿变更采矿方法后采场的回采爆破参数,运用传统经验公式计算出爆破参数取值范围,根据极限学习机(ELM)理论,以矿岩容重、弹性模量、抗压强度等6个因素作为输入因子,以排距、孔底距、炸药单耗3个指标作为输出因子,并利用国内应用较成功的上向扇形中深孔崩矿的7个矿山情况为学习、训练样本,建立矿山回采爆破参数优化预测模型。综合经验公式和预测模型的结果,确定采区爆破参数:炮孔排距为1.3 m,孔底距为1.8 m,炸药单耗为0.5 kg/t。优选爆破参数适应本采区工程条件,爆破效果好,震动影响小。     

低渗储层PRD钻井液微细固相的絮凝性能优化

以东方某低渗透气田储层为例,分别测试了重晶石粉、超细碳酸钙、膨润土粉、泥岩钻屑(储层段)在液相里的粒径分布情况,评价了他们对储层的损害程度,发现造浆膨润土和水化后泥岩,由于大部分颗粒在微米和亚微米级,对岩心渗流通道造成了堵塞。因此优选出了絮凝剂PL-1,其在加量为0.1%时对微细固相具有好的絮凝能力,并能明显增强钻井液的储层保护能力,被优化后的PRD钻井液污染的岩心,渗透率恢复值由优化前的66.9%提高到79.7%,而且钻井液的滤失造壁性也得到了改善。     

迪那3区块致密砂岩气藏损害机理及储层保护技术

迪那3区块致密砂岩气藏属于典型的低孔、特低渗碎屑岩储层,初始含水饱和度低,非均质性严重,裂缝发育,黏土矿物含量较高,该区块原用钾聚磺体系对迪那区块气藏造成一定的伤害,储层保护效果亟待提高。在分析迪那2及迪那3区块致密砂岩气藏特征及损害机理的基础上,确定钾聚磺体系损害气藏机理为水敏、应力敏感、漏失、毛管力效应及相圈闭损害。通过研制可酸化防漏堵漏材料及防水锁剂,对现用的钾聚磺体系进行改进,形成了一套保护致密砂岩气藏储层的钻井完井液体系,该体系流变性良好,滤失量明显降低,渗透率恢复值大幅提高,储层保护效果明显。     

Advanced Concentration Gradient Cathode Material with Two‐Slope for High‐Energy and Safe Lithium Batteries

Li[Ni_0.65Co_0.13Mn_0.22]O₂ cathode with two‐sloped full concentration gradient (TSFCG), maximizing the Ni content in the inner part of the particle and the Mn content near the particle surface, is synthesized via a specially designed batch‐type reactor. The cathode delivers a discharge capacity of 200 mAh g^?1 (4.3 V cutoff) with excellent capacity retention of 88% after 1500 cycles in a full‐cell configuration. Overall electrochemical performance of the TSFCG cathode is benchmarked against conventional cathode (CC) with same composition and commercially available Li[Ni_0.8Co_0.15Al_0.05]O₂ (NCA). The TSFCG cathode exhibits the best cycling stability, rate capability, and thermal stability of the three electrodes. Transmission electron microscopy analysis of the cycled TSFCG, CC, and NCA cathodes shows that the TSFCG electrode maintains both its mechanical and structural integrity whereas the NCA electrode nearly pulverizes due to the strain during cycling.