具有良好可再生性的新型二氧化硅磁性氧化石墨烯纳米复合材料

Graphene oxide (GO) wrapped Fe₃O₄ nanoparticles (NPs) were prepared by coating the Fe₃O₄ NPs with a SiO₂ layer, and then modifying by amino groups, which interact with the GO nanosheets to form covalent bonding. The SiO₂ coating layer plays a key role in integrating the magnetic nanoparticles with the GO nanosheets. The effect of the amount of SiO₂ on the morphology, structure, adsorption, and regenerability of the composites was studied in detail. An appropriate SiO₂ layer can effectively induce the GO nanosheets to completely wrap the Fe₃O₄ NPs, forming a core-shell Fe₃O₄@SiO₂@GO composite where Fe₃O₄@SiO₂ NPs are firmly encapsulated by GO nanosheets. The optimized Fe₃O₄@SiO₂@GO sample exhibits a high saturated adsorption capacity of 253 mg·g?1 Pb(II) cations from wastewater, and the adsorption process is well fitted by Langmuir adsorption model. Notably, the composite displays excellent regeneration, maintaining a ~90% adsorption capacity for five cycles, while other samples decrease their adsorption capacity rapidly. This work provides a theoretical guidance to improve the regeneration of the GO-based adsorbents.     

微波预处理对复杂铜矿磨矿及浮选动力学的影响

The effect of CaCO₃, Na₂CO₃, and CaF₂ on the reduction roasting and magnetic separation of high-phosphorus iron ore containing phosphorus in the form of Fe₃PO₇ and apatite was investigated. The results revealed that Na₂CO₃ had the most significant effect on iron recovery and dephosphorization, followed by CaCO₃, the effect of CaF₂ was negligible. The mechanisms of CaCO₃, Na₂CO₃, and CaF₂ were investigated using X-ray diffraction (XRD), scanning electron microscopy and energy dispersive spectrometry (SEM–EDS). Without additives, Fe₃PO₇ was reduced to elemental phosphorus and formed an iron–phosphorus alloy with metallic iron. The addition of CaCO₃ reacted with Fe₃PO₇ to generate an enormous amount of Ca₃(PO₄)₂ and promoted the reduction of iron oxides. However, the growth of iron particles was inhibited. With the addition of Na₂CO₃, the phosphorus in Fe₃PO₇ migrated to nepheline and Na₂CO₃ improved the reduction of iron oxides and growth of iron particles. Therefore, the recovery of iron and the separation of iron and phosphorus were the best. In contrast, CaF₂ reacted with Fe₃PO₇ to form fine Ca₃(PO₄)₂ particles scattered around the iron particles, making the separation of iron and phosphorus difficult.     

不同硅饱和系数水榴石的碳酸化分解动力学

Carbonated decomposition of hydrogarnet is one of the vital reactions of the calcification–carbonation method, which is designed to dispose of low-grade bauxite and Bayer red mud and is a novel eco-friendly method. In this study, the effect of the silica saturation coefficient (x) on the carbonation of hydrogarnet was investigated from the kinetic perspective. The results indicated that the carbonation of hydrogarnets with different x values (x = 0.27, 0.36, 0.70, and 0.73) underwent two stages with significantly different rates, and the kinetic mechanisms of the two stages can be described by the kinetic functions R3 and D3. The apparent activation energies at Stages 1 and 2 were 41.96–81.64 and 14.80–34.84 kJ/mol, respectively. Moreover, the corresponding limiting steps of the two stages were interfacial chemical reaction and diffusion.     

一种超重力燃烧合成制备高性能高熵合金的新方法

A new method of high-gravity combustion synthesis (HGCS) followed by post-treatment (PT) is reported for preparing high-performance high-entropy alloys (HEAs), Cr_0.9FeNi_2.5V_0.2Al_0.5 alloy, whereby cheap thermite powder is used as the raw material. In this process, the HEA melt and the ceramic melt are rapidly formed by a strong exothermic combustion synthesis reaction and completely separated under a high-gravity field. Then, the master alloy is obtained after cooling. Subsequently, the master alloy is sequentially subjected to conventional vacuum arc melting (VAM), homogenization treatment, cold rolling, and annealing treatment to realize a tensile strength, yield strength, and elongation of 1250 MPa, 1075 MPa, and 2.9%, respectively. The present method is increasingly attractive due to its low cost of raw materials and the intermediate product obtained without high-temperature heating. Based on the calculation of phase separation kinetics in the high-temperature melt, it is expected that the final alloys with high performance can be prepared directly across master alloys with higher high-gravity coefficients.     

窄板坯结晶器内连铸工艺参数对钢液流场的影响

Computational simulations and high-temperature measurements of velocities near the surface of a mold were carried out by using the rod deflection method to study the effects of various operating parameters on the flow field in slab continuous casting (CC) molds with narrow widths for the production of automobile exposed panels. Reasonable agreement between the calculated results and measured subsurface velocities of liquid steel was obtained under different operating parameters of the CC process. The simulation results reveal that the flow field in the horizontal plane located 50 mm from the meniscus can be used as the characteristic flow field to optimize the flow field of molten steel in the mold. Increases in casting speed can increase the subsurface velocity of molten steel and shift the position of the vortex core downward in the downward circulation zone. The flow field of liquid steel in a 1040 mm-wide slab CC mold can be improved by an Ar gas flow rate of 7 L·min?1 and casting speed of 1.7 m·min?1. Under the present experimental conditions, the double-roll flow pattern is generally stable at a submerged entry nozzle immersion depth of 170 mm.     

电渣重熔脱硫技术研究进展

Electroslag remelting (ESR) gives a combination of liquid metal refining and solidification structure control. One of the typical aspects of liquid metal refining during ESR for the advanced steel and alloy production is desulfurization. It involves two patterns, i.e., slag–metal reaction and gas–slag reaction (gasifying desulfurization). In this paper, the advances in desulfurization practices of ESR are reviewed. The effects of processing parameters, including the initial sulfur level of consumable electrode, remelting atmosphere, deoxidation schemes of ESR, slag composition, melting rate, and electrical parameters on the desulfurization in ESR are assessed. The interrelation between desulfurization and sulfide inclusion evolution during ESR is discussed, and advancements in the production of sulfur-bearing steel at a high-sulfur level during ESR are described. The remaining challenges for future work are also proposed.     

利用皮秒激光烧蚀制备非球形铝纳米颗粒

We report the picosecond laser ablation of aluminum targets immersed in a polar organic liquid (chloroform, CHCl₃) with ~2 ps laser pulses at an input energy of ~350 μJ. The synthesized aluminum nanoparticles exhibited a surface plasmon resonance peak at ~340 nm. Scanning electron microscopy images of Al nanoparticles demonstrated the spherical morphology with an average size of (27 ± 3.6) nm. The formation of smaller spherical Al nanoparticles and the diminished growth could be from the formation of electric double layers on the Al nanoparticles. In addition to spherical aluminum nanoparticles, triangular/pentagonal/hexagonal nanoparticles were also observed in the colloidal solution. Field emission scanning electron microscopy images of ablated Al targets demonstrated laser induced periodic surface structures (LIPSSs), which were the high spatial frequency LIPSSs (HSF-LIPSSs) since their grating period was ~280 nm. Additionally, coarse structures with a period of ~700 nm were observed.     

Mineral transition and formation mechanism of calcium aluminate compounds in CaO?Al2O3?Na2O system during high-temperature sintering

The mineral transition and formation mechanism of calcium aluminate compounds in CaO?Al₂O₃?Na₂O system during the high-temperature sintering process were systematically investigated using DSC?TG, XRD, SEM?EDS, FTIR, and Raman spectra, and the crystal structure of Na₄Ca₃(AlO₂)₁₀ was also simulated by Material Studio software. The results indicated that the minerals formed during the sintering process included Na₄Ca₃(AlO₂)₁₀, CaO·Al₂O₃, and 12CaO·7Al₂O₃, and the content of Na₄Ca₃(AlO₂)₁₀ could reach 92wt% when sintered at 1200°C for 30 min. The main formation stage of Na₄Ca₃(AlO₂)₁₀ occurred at temperatures from 970 to 1100°C, and the content could reach 82wt% when the reaction temperature increased to 1100°C. The crystal system of Na₄Ca₃(AlO₂)₁₀ was tetragonal, and the cells preferred to grow along crystal planes (110) and (210). The formation of Na₄Ca₃(AlO₂)₁₀ was an exothermic reaction that followed a secondary reaction model, and its activation energy was 223.97 kJ/mol.     

含细夹层的分矿充填层中流动特性的可视化

Ore particles, especially fine interlayers, commonly segregate in heap stacking, leading to undesirable flow paths and changeable flow velocity fields of packed beds. Computed tomography (CT), COMSOL Multiphysics, and MATLAB were utilized to quantify pore structures and visualize flow behavior inside packed beds with segregated fine interlayers. The formation of fine interlayers was accompanied with the segregation of particles in packed beds. Fine particles reached the upper position of the packed beds during stacking. CT revealed that the average porosity of fine interlayers (24.21%) was significantly lower than that of the heap packed by coarse ores (37.42%), which directly affected the formation of flow paths. Specifically, the potential flow paths in the internal regions of fine interlayers were undeveloped. Fluid flowed and bypassed the fine interlayers and along the sides of the packed beds. Flow velocity also indicated that the flow paths easily gathered in the pore throat where flow velocity (1.8 × 10?5 m/s) suddenly increased. Fluid stagnant regions with a flow velocity lower than 0.2 × 10?5 m/s appeared in flow paths with a large diameter.     

网络环境下高等学校院系资料室的重新定位

分析了目前我国高等学校院系资料室的现状以及存在的主要问题,重点探讨了网络环境下高等学校资料室的重新定位问题.院系资料室应该把书刊文献移交图书馆管理,建议高校的院系资料室着重灰色文献的管理利用,直接服务于本院系的教学和科研工作.     

以人为本的哲学意蕴

以人为本是合乎哲学发展史逻辑的科学命题，这一命题的形成经历了以物为本——以神为本——以人为本（以自然的人为本——以理性的人为本——以现实的人为本）的圆圈运动；以人为本的理论基础是科学的实践观；观人为本是马克思主义哲学的精蕴所在，它同精髓——实事求是、精华——社会发展规律学说一起构成马克思主义哲学理论体系的三个基本点；以人为本原则是中国共产党的根本指导原则。     

钝顶螺旋藻的混合营养分批和流加培养

在４Ｌ小型发酵罐对钝顶螺旋藻混合舂批和流加培养进行研究,在混合营养流加２中获得１０．２ｇ／Ｌ的最大细胞浓度,在这个浓度分别是混合营养分批的营养的３．８ ,光合自养分批培养的７．２倍,而细胞们率则分别为混合营养分批２的２．８倍,光合自养分批２的４．９倍。     

基于粗糙集的车牌字符识别方法

提出了一种基于粗糙集理论的车牌字符识别的方法，通过粗糙集的属性约简，有效地压缩了图像的特征数目，提高了运行效率，并且采用基于影响因子的图像判别算法，有效地提高了识别的准确率．以在高速公路收费站实地拍摄的车牌图像为样本，经过车牌的定位、分割，以及字符的分割，选取其中的300幅字符图像作为训练集，100幅字符图像作为测试集，实验结果表明：将训练集图像作为输入，正确识别率为100％；将测试集作为输入，正确识别率为86％。     

应用型人才培养中大学生创新平台的建立

通过机械类学生创新能力与实践能力的培养事例,阐述了以学生为中心,以兴趣为导向,以CAD协会为平台,以创新设计为手段,以校内外竞赛为激励机制的课外培养体系,构建集教学、训练和创新活动为一体的新型教育平台,达到应用型创新人才培养目标.     

20世纪90年代党领导意识形态工作的历史经验

既要坚持主流意识形态的价值导向，又要繁荣文化市场；既要吸收外来文化又要以我为主，为我所用；既坚持精神产品的社会效益第一，又要处理好与文化“商品”的经济效益的关系；既要弘扬主旋律文化又要坚持百花齐放。     

高校青年体育教师的可持续发展研究

青年体育教师必须以理论为先导，以能力为本位，以人格为力量才能实现白身可持续发展的目标。本文从理论、能力和人格三方面，阐述其对青年体育教师发展的意义。     

洛丽塔：沉默的镜像与缺场的主角——论纳博科夫“洛丽塔”形象的多重共构

纳博科夫因《洛丽塔》的出版畅销而改变了经济窘境并进而奠定了其后现代主义大师的地位。洛丽塔这一形象在小说中是沉默而缺场的,她由小说男主人公亨伯特、小说创作者纳博科夫和小说阅读者三方共同参与建构。亨伯特之洛丽塔是其童年记忆投射的镜像,是幻象之物;纳博科夫之洛丽塔是他独特的艺术创造,是制谜之物;读者之洛丽塔则是视域融合后镜像与谜底的再生成,是共构之物。     

汉越语与中古汉语的舌面音韵尾比较

在汉越语中鼻音韵尾、塞音韵尾分布十分整齐.汉越语中的对应,暗示着中古汉语语音系统对应性.有一些证据表明,中古汉语"梗摄"和"宕摄"的阳声韵以舌面鼻音收尾,入声韵以舌面塞音收尾,这样中古汉语的鼻音、塞音分布也十分整齐对称.     

保温砌筑砂浆的制配与性能试验

以P.O.42.5级水泥为主要胶凝材料,碎渣砂、陶砂为骨料,并加入适量的粉煤灰、硅灰辅助胶凝材料和复合外加剂及聚丙烯纤维,以增加砂浆的流动性、匀质性、稳定性、保水性和减少收缩性,研制出具有一定强度和保温性能的保温砌筑砂浆,完全满足蒸压加气混凝土砌块自保温承重或非承重墙体砌筑要求.