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.     

改良灌肠方法降低上消化道出血并发症发生率疗效评价

目的 降低上消化道出血肝性脑病的发生率。方法 改进型乳果糖灌肠方法。结果 应用改进型灌肠方法使上消化道出血肝性脑病的发生率由原来的45．5％降至目前的21．2％；肝性脑病病人的苏醒时间由平均11．9h缩短至3．6h。结论 改进型灌肠方法是一种良好的预防和治疗上消化道出血并发肝性脑病的方法。     

消化道大出血急诊剖腹探查术中纤维内镜的应用研究

目的：探讨术中纤维内镜在消化道大出血急诊剖腹探查术中的应用价值．方法：对20例不明原因急性消化道大出血须急诊剖腹探查的患者进行术中内镜检查,总结和评价其应用价值．结果：19例患者通过术中内镜检查明确了出血部位及原因,其阳性检出率达95％．其中十二指肠降部单发腺瘤2例,十二指肠水平部Dieulafoy病1例,十二指肠淋巴瘤1例,空肠间质瘤2例,回肠淋巴瘤2例,小肠海绵状血管瘤5例,小肠动静脉畸形5例,胃空肠吻合口出血1例．检查用时15-20min．患者经术中内镜检查明确出血部位及原因后行相关手术治疗,术后无1例出现消化道再出血．结论：不明原因急性消化道大出血急诊剖腹探查时,术中内镜的应用大大提高病变检出率,及时明确出血部位而采取相应治疗,且定性准确、安全可靠．     

三黄明胶液贯肠在克隆氏病急救止血中的应用

克隆氏病常见于下消化道,为全肠壁非特异性肉芽肿性肠炎,多伴有发热、腹痛、粘膜溃疡和下消化道大出血等症状。用中药黄莲、黄芪、蒲黄粉和明胶液贯肠,治疗克隆氏回、结肠炎广泛溃疡大出血,可起到退热、消炎、排脓、止血、促进溃疡愈合及提高机体免疫功能的等作用。该方法在急性菌痢,伤寒、阿米巴或血吸虫性肠炎的应急治疗中也将有一定的临床参考价值。     

上消化道出血的观察与护理

本文对1996年-1999年我科ICU收治的22例上消化道出血病人的观察与处理作了总结分析.22例中治愈好转18例,死亡4例,好转率为82%.及时发现病情变化,及时正确的处理,提高了抢救成功率,降低了死亡率.     

去甲肾上腺素治疗上消化道出血20例临床观察

用去甲明上腺素治疗上消化道出血20例,治疗时间1－2天,有效率100％。     

三角帆蚌消化系统的组织学研究及其胃肠在饥饿状态下的变化

三角帆蚌消化系统由消化腺－肝脏和消化道－口、食道、胃、肠组成。肝脏为分枝的复管腺，腺细胞呈现出两种细胞，另一种为未成熟细胞。消化道由粘膜层、粘膜下层和外膜构成，无肌层。粘膜上皮均为单层柱状上皮，游离面具纤毛和微绒毛。不同部位的粘膜下层略有区别。     

上消化道动态多生理参数记录分析技术的研究

研制了１种新的用于上消化道功能疾病研究诊断的动态多生理参数记录分析系统．此系统借助置于体内的传感器导管和便携式记录盒，对胃酸、食道酸、心电进行２４ｈ动态连续记录监测，记录结束后，将数据传输给计算机进行分析．文章论述了传感器、记录器、数据分析等关键技术；给出了新研制的多参数集成的传感器导管的原理、结构及性能；介绍了记录器的结构和功能；讨论了数据分析、信号处理的方法和过程．胃液抽取法和动态监测法对照的动物实验证实了技术的可靠性．临床应用研究表明这项研究对非心源性胸痛等上消化道功能性疾病的研究诊断有着重要的意义     

丽纹龙蜥消化管的组织结构观察

利用组织学方法对丽纹龙蜥的消化管进行了观察,结果显示:消化管壁由粘膜层、粘膜下层、肌层和外膜组成。食管粘膜为复层扁平柱状上皮、胃、小肠和直肠上皮为单层柱状上皮。管壁皱襞的形态、腺体分布情况、肌层的相对厚度等在消化道各部存在差异。小肠具有明显的空肠分化。研究表明丽纹龙蜥消化管的结构特征与其食性相适应,与鸟类和哺乳类动物相比,具有一定的不完善性和低等性。     

三种鼠类消化道长度和重量的比较

为了解动物消化道形态可塑性的变化与食性、食物质量之间的关系,对黑线仓鼠、棕色田鼠和小白鼠的消化道形态进行了比较分析.研究结果表明:三种鼠类的消化道形态存在差异;消化道长度不仅仅取决于食性,还受食物质量的影响;食性和食物质量的差异可能会引起不同消化器官形态结构产生适应性反应.胃的形态结构主要与生活习性有关,小肠与食物质量关系紧密,盲肠和大肠与则主要反映食性的差别.     

蛤蚧消化道嗜银细胞的分布及形态学观察

用龙桂开银浸法对蛤蚧消化道嗜银细胞的分布及形态作了观察，结果表明：蛤蚧消化道嗜银细胞在胃贲门部和幽门部分布密度大，胃体部密度小，呈“U”形分布；在十二指肠密度大，从空肠到回肠密度逐渐变稀；在大肠上、下段分布密，中段稀，也呈“U”形分布；从食道中段到下段密度中等，并呈递增分布．细胞颗粒被染成黑色、棕黑色，细胞形态多样，有锥体形、三角形、长梭形等。主要分布在黏膜上皮和腺上皮之间，在结缔组织里发现有少量的嗜银细胞，细胞充满嗜银颗粒，嗜银颗粒在细胞外有时可见到。