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.     

以人为本——科学发展观的基石

“以人为本”科学地揭示了发展的本质,认为人的全面发展是发展的本质、发展的目的、发展的动力、发展的标志。“以人为本”全面规定了发展的内容。认为实现人的全面发展,必须坚持以经济建设为中心,推进物质文明建设、政治文明建设、精神文明建设的全面发展。“以人为本”确立了协调发展的原则。认为实现人的全面发展,必须在全面发展的基础上作到协调发展。没有协调发展,就难以实现人的全面发展和社会的全面进步。“以人为本”指明了可持续发展的道路。     

基于人文关怀视角的高校教师发展本质研究

现代高校教师被视为高等教育改革的中心和核心要素。人文关怀视角的高校教师发展本质研究,能够有效促进高校教师的发展。其构成表现为生存发展、学术发展、自由发展、独立发展、创新发展及精神发展,其价值体现为生命本体价值、学术操守价值及精神信仰价值,并从人文精神、人文文化、人文制度及人文环境等方面进行建构。     

对发展代价的反思是科学发展观产生的重要原由

在新世纪新阶段，中国共产党之所以提出科学发展观，其重要原由之一是基于对发展代价的反思。科学发展观对当代世界的发展代价进行了深刻反思，反映了当代最新的发展理念；同时也对我国改革开放以来的发展代价进行了深刻反思，是与时俱进的发展观。贯彻和落实科学发展观，可以防范和化解发展带来的风险，控制和减少发展的代价，更好地实现经济社会又好又快地发展。     

发展中国家社会经济发展观的历史演进

二战后,发展中国家对社会经济发展的认识经历了从单纯经济发展到追求经济社会全面发展,从短期发展到谋求可持续发展,从以物为中心的发展到以人为中心的发展这样一个发展变迁过程。中国作为最大的发展中国家,在新的历史时期提出科学发展观,丰富了发展中国家的社会经济发展理论。     

简论发展哲学的基本问题

发展哲学的基本问题也就是发展过程的基本问题,任何发展实践都自始至终存在着发展主体与发展客体、发展理想与生存现实、发展理论与发展实践的矛盾运动,发展哲学的基本问题也必然是这三对矛盾.发展哲学的核心内容和基本矛盾就是这三对矛盾的相互作用.只有发展哲学才能实现当代哲学的转型与飞跃,才能实现中、西、马在当代中国社会发展语境下的综合创新与辩证统一,凝聚和形成当代中国社会发展的时代精神.     

秦皇岛城乡体育一体化发展模式及对策研究

本文提出构建秦皇岛城乡体育的一体化发展模式,从制定本地区城乡体育一体化发展目标出发,围绕政策制定、经费投入、场地设施、组织管理和活动开展等五个重点发展方向规划城乡体育的一体化发展,提出了促进秦皇岛城乡体育一体化发展的对策建议。     

高性能混凝土技术可持续发展概念的研究

就高性能混凝土技术的可持续发展问题进行了论述，进一步阐明了高性能混凝土在可持续发展意义下的概念。指出高性能混凝土技术的发展，要协调资料消耗与人类生存环境及人类发展长远利益的关系。应用可持续发展的基本原理，论述了对高性能混凝土技术基要求和其本必须遵循的发展规律。提出了在可持续发展的前提下，高性能混凝土技术的发展要求和具体措施，绿色混凝土技术发展已经纳入发展进程。指出可持续发展是高性能混凝土技术的必由之路。     

西部大开发以来内蒙古可持续发展系统评价研究

基于区域人口、资源、环境与经济系统的协调发展的层面,探讨了内蒙古可持续系统协调发展问题.在对内蒙古可持续发展系统要素构成及西部开发以来内蒙古可持续发展系统状态进行分析的基础上,建立内蒙古可持续发展系统评价指标体系,采用相对比较成熟的主成分分析与回归分析相结合的综合评价方法来分析西部大开发以来内蒙古可持续发展水平及协调发...     

山东省能源经济环境系统协调发展评价研究

山东省能源经济环境系统协调发展评价有助于山东省把握能源经济环境系统发展的规律,寻求存在的不足及原因,为山东省科学持续发展提供决策依据.构建了包含三个目标、11个准则和22个具体指标的山东省能源经济环境系统协调发展评价指标体系.基于主成分TOPSIS价值函数和离差函数,构建了子系统发展度、子系统两两协调度、子系统两两协调发展度以及系统总体协调度等能源经济环境系统协调发展评价模型.运用其对山东省1995—2010年的能源经济环境系统协调发展进行评价,进而提出了促进山东省能源经济环境系统协调发展的相关对策.     

学校发展的终极境界是实现人的全面发展

实现人的全面、和谐发展,是以人为本的科学发展观的核心内容,也是学校发展的根本目的。高校落实科学发展观,就必须为促进和实现人的全面发展而不懈努力,因此,要切实把促进和实现培养目标（人）的全面发展放在首要位置,同时高度重视培养人的人（教职工）的全面发展。此外,还要进一步更新观念,创新思维,把对学校发展终极目标的追求内化为全校上下的共同行为,并且在“服务社会作贡献”过程中,提升促进实现学校发展终极目标的层次和水平。