Cu掺杂对有序Sr3YCo4-xCuxO10.5+δ多晶的结构与物理性能的影响

采用固相反应法制备了四方Sr3YCo4-xCuxO10.5+δ(x=0~1.0)多晶。用热重-差示扫描量热分析,X射线衍射研究了多晶的有序化相变及结构。在固溶范围内(x=0~0.4),观察到有序峰(103)和(215),说明四方Sr3YCo4-xCuxO10.5+δ多晶为超结构,这是由于合成时在1000℃以上发生了吸氧(δ)有序化相变；当x=0.6~1.0时,978℃时在晶界处形成了单斜杂相,破坏了Sr3YCo4-xCuxO10.5+δ多晶的有序。当x=0~0.4时,多晶呈半导体输运行为。随着Cu掺杂量的增加,Co4+提供的空穴载流子浓度增大,电阻率明显下降；由于Cu的固溶,自旋熵增加,载流子浓度和自旋熵的共同作用使x=0~0.2多晶的热电势不变,x=0.4的热电势降低。并且Cu掺杂导致的晶格畸变使Co3+离子由高自旋态转变为高/低自旋混合态,磁化强度和铁磁转变温度(Tc)降低,磁结构由G-型反铁磁转变为铁磁。在进行二次烧结后,300K时电阻率明显降低,热电势为一次烧结的2倍,可能是二次烧结使多晶的有序化程度增大,提高了铁磁有序排列。     

A high-throughput chaotic advection microreactor for preparation of uniform and aggregated barium sulfate nanoparticles

A high-throughput (105.5 g/h) passive four-stage asymmetric oscillating feedback microreactor using chaotic mixing mechanism was developed to prepare aggregated Barium sulfate (BaSO₄) particles of high primary nanoparticle size uniformity. Three-dimensional unsteady simulations showed that chaotic mixing could be induced by three unique secondary flows (i.e., vortex, recirculation, and oscillation), and the fluid oscillation mechanism was examined in detail. Simulations and Villermaux–Dushman experiments indicate that almost complete mixing down to molecular level can be achieved and the prepared BaSO₄ nanoparticles were with narrow primary particle size distribution (PSD) having geometric standard deviation, σ_g, less than 1.43 when the total volumetric flow rate Q_total was larger than 10 ml/min. By selecting Q_total and reactant concentrations, average primary particle size can be controlled from 23 to 109 nm as determined by microscopy. An average size of 26 nm with narrow primary PSD (σ_g = 1.22) could be achieved at Q_total of 160 ml/min.     

行李箱外板浮动整形模设计

介绍了某轿车行李箱外板的翻边侧整形模设计过程,行李箱外板的侧法兰翻边上存在凹包,其翻边方向和凹包成形方向不同,常规需要2道工序分别完成翻边和凹包成形。该模具突破了传统的设计结构,在翻边机构中设置了凹包成形机构,将2个不同方向的成形复合到1道工序中,减少了模具数量,降低了冲压成本和工装成本。     

CFETR水冷陶瓷增殖剂包层模块产氚率实验验证

水冷陶瓷增殖剂（WCCB）包层作为中国聚变工程试验堆（CFETR）候选包层之一，承担着氚增殖、核热提取、屏蔽等重要涉核功能，其中子学设计的可靠性直接影响CFETR氚自持目标的实现。为验证中子学设计工具，即MCNP和FNEDL3.0数据库，在WCCB包层中子学设计中的可靠性，基于研制出的WCCB包层模块，在DT中子环境下开展中子学实验，对以产氚率（TPR）为代表的中子学参数进行了模拟值（C）和实验值（E）对比分析。结果表明，模块中轴线位置处TPR的C/E为0.97?1.08，而模块边缘位置处TPR的C/E为0.65?0.82；模块钛酸锂层边缘区197Au（n，γ）198Au反应率的C/E为0.72?0.90，表明模块边缘区存在非期望的散射中子，导致该区TPR模拟值和实验值偏离较大。     

草原石林：东北亚早白垩世花岗岩伸展穹隆和岩浆成矿爆发的地质遗迹及其形成过程

东北亚地区至少发育9个大型草原石林,属花岗岩石林的一种,是东北亚早白垩世巨量伸展和第四系冰川、风化作用的共同产物,主要特点是发育密集的近水平节理。本文通过整理岩浆岩专题填图和构造研究发现,这些石林的主体是早白垩世东北亚地区巨量伸展过程中形成众多的不对称花岗岩穹隆或同减薄岩体,岩体边部发育韧性剪切带,核部发布近水平岩浆流动面理,伸展和岩浆多期侵位导致与成矿密切相关的岩浆热液大量上涌,岩体抬升至地表,沿岩浆面理发育密集的近水平节理和部分垂直节理,后期沿这些构造面理发生的物理风化和化学作用(包括风蚀、冰川以及盐风化等)造就了千奇百怪的形态。草原石林是花岗岩地貌中的“另类”,不仅具有指示东北亚地区花岗岩形成时代(早白垩世)的特点,也是寻找晚中生代中国北方大规模成矿的良好标志体,而且风化形成的千姿百态的景色极具观赏价值,可以作为整个蒙古草原地区和大兴安岭南段地区特色的地学科普和生态旅游资源。     

有机元素检测仪器在石油化工行业的需求和应用现状

本文通过对国内外石油及石化产品分析检测相关标准技术的调研与收集,以及相关检测仪器特点的分析,对目前包括润滑油、汽油、柴油、煤油、石蜡、石化聚合物、原油等样品类型,共计80个样品在现有仪器上进行测试,使用标准方法对样品中碳、氢、氮、硫元素进行检测,获取样品的检测时间、含量结果、仪器条件等参数,为相关仪器检测提供数据基础.     

Nb2O5-doped NiZnCo ferrite ceramics with ultra-high magnetic quality factor and low coercivity for high-frequency electronic devices

This work investigates the influence of niobium pentoxide (Nb₂O₅) as dopant, on the structural, magnetic, and dielectric properties of NiZnCo ferrites. The results showed that Nb₂O₅ was an effective dopant, and the Nb⁵⁺ ions entered the B site to replace Fe³⁺ ions, which altered the electromagnetic properties of the NiZnCo ferrite. In particular, the coercivity (H_c) was 20～24 Oe, and the magnetic quality factor (Q), was more than 200 at x = 0 and x = 0.1 wt%, which is 4～5 times higher than that of NiZn and NiCuZn ferrites. Excellent electromagnetic properties were obtained for 0.1 wt% Nb₂O₅-doped NiZnCo ferrite, i.e., M_s = 88.3 emu/g, H_c =20.4 Oe, ρ = 2.4 × 10⁵ Ω m and Q = 202 @20 MHz. These excellent electromagnetic properties of Nb₂O₅-doped NiZnCo ferrites could be potentially applied to resonators and capacitors at high frequency.