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.     

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.     

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.     

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.     

工科数学教学改革探讨

工科数学教学既要教思想、教方法，又要教做人；既面向全体学生、面向大多数，又要面向两头；要引导学生转变学习观念；同时应加强针对性，注重启发性，提高积极性等，以达到提高学生素质、培养学生能力的目的．     

增强高校网络德育实效性的立体考察

提高高校网络德育的实效性是一项综合性工程,需要开设网络德育课、创新网站德育内容以充分吸引大学生的注意力、创新德育教育手段和途径、建立开放式的互联德育立体网络、加强网络德育队伍的建设、建立和完善网络文化建设,特别是校园网络文化建设的维护机制、引导和鼓励大学生参加实践和加强制度建设,最终形成促进网络德育生态发展的机制。     

模因论与大学英语写作能力的提升和创新

模因论是近年来语用学界的新兴理论,为使大学英语专业学生的英语写作能力不断提升,必须最大限度地开发新的知识资源,注重模因的复制和传播,做到激励多读多记加大语言模因的储量;营造不同的情景提高模因变异与复合能力;扩展英语写作空间强化模因传播;精心设计课堂教学传播最大信息量.     

路径排序问题基于表面的DNA算法

提出了路径排序问题表面DNA算法三步骤：a．找出两端点的所有链,b．筛选出所有的路,c．得到路序．指出编码问题在DNA计算中的重要性．在算法实现过程中,用保护两端点对应的DNA片段3’端或5’端的办法得到所有的链,并用电泳的方法对链进行排序以及去掉链长大于图权值总和的链;对探针进行生物素标记并且采用观察、记录亮点强度的办法筛选出所有的路;分析实验记录得到路序．将算法推广到最短（长）路问题的不同之处在第三步,即只需分析在表面上排在最前（最后）的DNA链的实验记录就得到最短（长）路．     

党在西藏实行民族区域自治的理论与实践特色

党在西藏实行民族区域自治中，从过程到内容，从理论到实践，都有一些特点。“以特别真诚和尊重西藏民族的感情对待西藏民族”、“根据西藏人民觉悟意愿实际，稳步推进民族区域自治”、“民族、宗教界上层爱国人士发挥了特殊历史作用”、“十分强调给西藏经济发展以支持帮助”、“特别注意保护发展西藏的民族化”、“突出强调维护祖国统一与民族团结”就是其主要表现。     

设备管理与资产效益

实现企业经济效益的重要手段是合理配置设施设备，要从4个方面进行设备管理，一要谨慎投资，规避风险，二要抓好维护，确保效能，三要提高装置适应性，增加资产效益；四要搞好设备的价值管理。     

庐山地质地貌分析及其实习路线设计

庐山综合自然地理实习是很多高校地理专业学生的必修课。本文从理论上分析了庐山的地质、构造地貌、河谷地貌和冰川地貌,结合实地考察,提出了庐山地貌实习的三条路线与内容:莲牯路—剪刀峡—小天池—王家坡—莲花谷—大月山—大校厂—东谷;如琴湖—锦锈谷—龙首崖—石门涧—电站大坝—黄龙潭—芦林桥;犁头尖—太乙峰—含鄱口—五老峰—三叠泉。     

水泥稳定碎石基层水泥用量的研究

作为＂重载交通长寿命沥青路面关键技术研究＂的依托工程,对其基层主要有三个方面的要求：增加基层厚度以降低其应力水平;提出适宜的级配设计及级配检验方法优化级配,适当增加水泥用量提高基层强度,使其承载能力能满足七天无侧限抗压强度达到6MPa,同时减小其承载能力的变异性以保持路面承载能力稳定性;加强施工质量控制,提出合适的施工工艺以提高混合料的均匀性、厚度的均匀性以及压实度的均匀性。     

民事审判事实认定中经验法则的运用初探

民事审判以事实为根据包括三类事实:当事人无需举证证明的事实;需要当事人举证证明达到事实清楚或者高度盖然性的事实;介于两者之间的需要当事人举出一定的证据但又达不到高度盖然性的标准根据经验法则可以认定的事实。民事审判中运用经验法则认定事实容易造成对案件事实的误认且比较混乱。正确运用经验法则认定案件事实需要立法和司法解释,也需要进行广泛宣传达成共识。     

清刚粹美:王夫之教化思想探析

从宇宙进化、人性生成、伦理追求和教育规律等方面对王夫之的教化思想进行了分析和阐释,并指出了其现实意义:人类的优秀文化是天地间清刚粹美之气的凝聚,以之教化社会,社会便可日生而新,和谐安宁而又充满活力。中华民族要有一个光明的未来,就必须致力于优秀文化,特别是优秀审美文化的教化,弘扬清刚粹美、止争一线的天地正气。