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.     

论体育课程的内部关系

从7个方面论述了体育课程的内部关系:生活性动作技能与运动性动作技能的关系、学校体育课程内容与竞技体育运动项目的关系、本土体育与外来体育的关系、知识与技能的关系、运动知识和技能与健康知识和技能的关系、课程内容与体质健康标准测试内容的关系、体育学科课程与体育活动课程的关系.     

英汉句法差异及其转换翻译浅议

语言是思维的外壳，思维是语言的脊梁。英汉两民族思维习惯的不同，造就了英汉两种语言句法上的根本差异。这些差异具体表现为形态语和无形态语、树型结构与线型结构、形合与意合、有主句和无主句、人称主语句式与非人称主语句式以及句首重心与句尾重心之间的差异。充分认识这些差异，并在翻译过程中进行相应转换和调整，才能使译自如圆润。     

思政课教材体系向教学体系转化需处理好的若干重要关系

认为在思政课教学中需要处理好以下六个关系:一是要正确处理好各门课程之间的关系,二是正确处理好每门课程各个部分之间的关系,三是正确处理好教材内容与教学内容的关系,四是正确处理好教师主导作用与学生主体地位的关系,五是正确处理好理论教学与实践教学的关系,六是正确处理好标准化教学与差异化教学的关系。     

断-砂配置油气聚集条件及油气富集主控因素分析

为了研究断-砂配置在油气藏形成与分布中的作用,在断-砂配置所形成油气藏类型及特征研究的基础上,采用断-砂配置与油气分布之间空间配置关系分析的方法,对断-砂配置的油气聚集条件及油气富集的主控因素进行了研究。结果表明:油气运移条件不同,断-砂配置油气聚集条件也不同。油气沿砂体侧向运移条件下断-砂配置油气聚集条件是断层侧向封闭,而油气沿断裂垂向运移条件下断-砂配置油气聚集条件是上覆存在区域性盖层阻挡。断-砂配置油气富集主要受到3个因素的控制:1反向断裂有利于断-砂配置油气聚集成藏;2交叉断裂有利于断-砂配置油气聚集成藏;3断层侧向封闭性控制着断-砂配置油气富集程度。     

杂交水稻品质性状与农艺性状的相关性分析

通过对杂交水稻品质性状与农艺性状进行相关分析,结果表明:小区产量和穗着粒数对各品质性状具有一定相关,但未达到显著水平,其它农艺性状均对不同品质性状相关达到显著或极显著,其中穗实粒数对整精米率、直链淀粉含量、长宽比正相关达显著水平以上,结识率对整精米率、蛋白质含量、胶稠度、长宽比正相关达显著水平以上,株高对整精米率和蛋白质呈负相关达显著水平以上,播始历期对垩白米率、垩白度、蛋白质含量负相关达极显著水平,千粒重对整精米率负相关达极显著水平.通过对外观品质与其它品质性状相关分析,结果表明:长宽比与蛋白质含量、整精米率呈极显著负相关,与直链淀粉含量呈负相关,垩白米率与直链淀粉含量呈极显著正相关,与蛋白质含量呈显著正相关,与胶稠度呈负相关,垩白度与与蛋白质含量、直链淀粉含量呈正相关,与胶稠度呈负相关.     

上下级沟通、组织承诺与大学生就业稳定性的关系

为研究上下级沟通、组织承诺与大学生就业稳定性这三者之间的关系，采用因子分析与回归分析方法构建上下级沟通、组织承诺与大学生就业稳定性的关系模型，采用多阶段抽样法，对456名大学毕业生进行问卷调查。研究结果表明：上下级沟通和组织承诺均能正向影响大学生就业稳定性，越是良好的上下级沟通和组织承诺，大学生就业稳定性越强；同时，上下级沟通还正向作用于组织承诺，组织承诺在上下级沟通对大学生就业稳定性的正向影响中起中介作用。     

金融创新要正确认识和处理好几对关系

金融创新需要正确认识并处理好几对关系，主要是：吸纳外国经验与确认国情现状的关系；金融改革与金融创新的关系；内在因素与金融环境的关系；科学预见与金融热点的关系；内部管理与外部调适的关系。     

粤北大学生心理健康状况调查分析

采用“心理卫生自评量表”(SCL-90)，对粤北大学生进行问卷调查，并用SPSS10．0软件对问卷进行数据统计分析，发现粤北大学生的SCL-90各因子均分与国内青年组常模相比，存在明显差异，同时还存在年级、城乡、理科、性别及独生子女与非独生子女之间的差异。     

论农民专业合作社法人治理结构的冲突与完善

我国农民专业合作社特殊的产权结构使其在治理结构上存在着社员民主控制与管理层专业化经营的冲突、平权式治理结构与少数人控制的冲突、劳动控制资本与成员利益诉求异质性的冲突。这些冲突实质上是农民专业合作社发展过程中守成与创新的冲突。如何权衡合作社发展过程的守成与创新是解决农民专业合作社治理结构冲突的突破口。     

社会互动与青少年成长环境中的几个关系

社会互动影响青少年的成长，其中具有重要意义的有家庭中的互动、学校中的互动、社会大环境中的互动和网络互动等。要处理好青少年成长环境中的几个关系：家庭——养和育的关系、学校一一传道和授业的关系、网络传媒——经济效益和社会效益的关系、社会——管和教的关系。