Synthesis of a foam ceramic based on ceramic tile polishing waste using SiC as foaming agent

Due to the large amount of ceramic tile polishing waste generated in China, the recycling of this waste residue becomes important. Herein a foam ceramic was successfully produced by using ceramic tile polishing waste as main raw material. In this research, SiC was added as the foam agent, and the foaming mechanism was also investigated. The results showed that the best dosage of SiC was 1%. Furthermore, in order to obtain a foam ceramic with better structure, the sodium phosphate was added in raw materials as foam stabilizer. The influence of this addition on the microstructure and properties of foam ceramic was investigated. It was found that the optimum additive amount of sodium phosphate is 2–3%.     

Quantitative analysis of toughening effect of crack deflection on Si3N4/Si2N2O composites through improved indentation method

In this study, Si₃N₄/Si₂N₂O composite ceramics prepared by hot pressing were used as an example, and the material fracture morphology and fracture mechanism were analyzed. Based on the formula of fracture toughness measured by an indentation method, a quantitative computation method was proposed to determine the toughened effect of ceramic materials resulting from the crack deflection by the second phase. The grain size and sintering density are increased with the increase of sintering temperature. The toughening effects resulting from the crack deflection is increased, and the main mode of fracture is transformed into the transgranular fracture. The Si₂N₂O grains can play a role in the toughening process because these grains can hinder the cracks extending along the radial direction. However, when the cracks extend in the axial direction, the toughening effect of Si₂N₂O grains is not obvious because of the internal stacking faults in the axial direction. The improved indentation method can quantitatively analyze the toughening effect of the second phase of composite ceramics, and the validity of this method are verified by comparing the fracture toughness of Si₃N4/Si₂N₂O and fine grained β- Si₃N₄ ceramics.     

Ti3C2Tx-foam as free-standing electrode for supercapacitor with improved electrochemical performance

To prevent restacking of the Ti₃C₂T_x layers, the Ti₃C₂T_x-foam has been successfully synthesized through thermal treatment of Ti₃C₂T_x-film with the hydrazine monohydrate. The interconnected porous structure of Ti₃C₂T_x-foam could effectively reduce the restacking of the Ti₃C₂T_x sheets and shorten the diffusion path of ions and accelerate the intercalation/de-intercalation of ions. The Ti₃C₂T_x-foam-80 used as free-standing electrode achieves a high areal capacitance of 271.2 mF/cm² (122.7?F/g) at a scan rate of 5?mV/s in 1?M KOH electrolyte. It also exhibited a high capability rate of 65.5% from 5?mV/s to 100?mV/s and good cycle life with 88.7% retention of its initial after 10,000 cycles at a scan rate of 50?mV/s.     

附加外场力对锌锅表层锌液流动和锌渣分布的影响

实测了热镀锌锌锅表层锌液的流速,并分析了锌锅浮渣的分布特点,提出了一种在锌锅锌液上方主动加载外场力作用以驱动锌液流动进而改变锌渣分布的新方法,称为锌渣流动管理方法(DFMS-Dross Flowing Management System)。通过源力加载的方式修正了流体动量守恒方程,建立了锌液流场数值计算模型,模拟了不同外场力加载布局下锌锅表层锌液的流场。结果表明,附加外场力作用可有效促进锌锅表层锌液的切向流动,最大切向流速可达0.8 m/s;表层锌液的切向流动可拖动锌渣跟随流动,进而改变锌渣分布,促进锌锅排渣,证实了DFMS的有效性。模拟结果还表明,锌锅表层锌液的切向流速受外场力加载时间的影响较小,而随加载外场力的增大而增大,但加载外场力的大小对100~200 mm深锌液的流速影响较小。最后,通过定义锌锅表层锌液的排渣时间因子讨论了不同外场力加载方式的排渣效率。     

靶向CD93分子探针制备及其生物学实验研究

CD93分子作为一种新型新生血管生成激活剂,有可能成为肿瘤监测的重要分子靶点,因此制备125I标记抗CD93单抗(125I-anti-CD93 mAb),研究其在荷瘤鼠体内生物学分布及磷屏显像特点,探讨其对A549肺癌靶向性及CD93阳性肿瘤监测的可行性。本文制备125I-anti-CD93 mAb及125I-IgG并进行鉴定;建立A549肺癌荷瘤小鼠模型,经尾静脉注射125I标记抗CD93单抗,并设125I-IgG为对照组,注药后不同时间进行生物学分布及磷屏放射自显影;肿瘤组织行HE染色及CD93免疫组织化学染色;采用统计软件对定量数据(x+s)进行统计学处理,组间数据用t检验,P<0.05为差异有统计学意义。结果表明,125I-anti-CD93 mAb及125I-IgG标记率、放射性比活度、放化纯度分别为91.37%和90.24%,1096.44 MBq/mg和1082.88 MBq/mg,96.49%和94.82%,放置72 h后两标记物的稳定性仍>90%,两者间无统计学差异(生理盐水组P=0.93,t=0.09,血清组P=0.13,t=1.90)。荷瘤鼠生物学分布结果显示125I-anti-CD93 mAb主要经肝肾代谢,注射后48 h时肿瘤组织放射性摄取率为(6.42±0.71)%ID/g,T/NT(瘤/对侧肌肉)摄取比值为4.45±0.86,显著高于对照组125I-IgG组(2.45±0.33/1.71±0.24),P<0.05,t=3.07和P<0.01,t=5.10。动态全身磷屏自显影结果可见,24 h两组小鼠轮廓清楚,48 h时实验组肿瘤显像最清晰,肿瘤放射性摄取比(肿瘤/对侧肌肉)为3.34±0.18,明显高于对照组(1.62±0.19),P<0.01,t=6.52。免疫组化染色结果证实肿瘤高表达CD93。125I-anti-CD93 mAb制备简便,对A549肺癌组织靶向性好,有望成为CD93阳性肿瘤监测的新型分子探针。     

重金属污染土壤回转窑协同处置和资源化利用

在中国，土壤中的重金属污染问题形势严峻，本文探索了一条采用先将重金属污染土壤中铅、镉、铜、锌固定再利用回转窑协同处置并资源化利用的技术途径。实验发现：添加适量的凹土及稳定化试剂并经稳定化处理以后，可以实现污染土壤由危险废物向一般固废的转变；进一步将稳定化处理后的土壤采用回转窑深度加工、能生产得到安全指标和产品性能合格的陶粒。经过优化实验方案后的结果显示，在铅、镉、铜、锌等重金属初始含量（上限）为2280mg/kg、592mg/kg、2000mg/kg、93400mg/kg的污染土壤添加4%的凹土（质量分数）及其他辅助材料后稳定化48h，上述重金属的可溶态检出量分别降低了50%、66%、59%、52%，经治理后的土壤可以转变为一般固废。用这种固定化处理后的土壤可以生产出合格的陶粒，而且在陶粒生产过程中逸散排放的铅、镉含量均低于大气污染物排放限制要求。     

稀土含量对Ti6Al4V钛合金等离子渗氮层组织和摩擦学性能的影响

目的研究稀土含量对Ti6Al4V钛合金表面等离子体渗氮层结构和性能的影响。方法运用等离子表面改性技术对Ti6Al4V(TC4)钛合金进行等离子渗氮处理,渗氮过程中通入不同含量的稀土作为催渗剂,以获得钛合金表面强化层。利用金相显微镜和扫描电子显微镜(SEM)观察渗氮层组织,用X射线衍射仪(XRD)分析渗层相组成,用能谱仪(EDS)检测渗层的化学成分,用维氏显微硬度计测量渗层的显微硬度,用球-盘式摩擦磨损试验机和三维轮廓仪检测渗层的摩擦磨损性能。结果TC4钛合金表面等离子渗氮层结构包括表面化合物层(主要成分为δ-TiN)和扩散层(主要为N原子扩散形成的N-Ti固溶体),加入稀土可以促进N原子向基体的扩散,提高渗氮速度。渗层厚度增加,硬度和耐磨性能提高,扩散层使钛合金基体与化合物层之间的硬度梯度更加平缓。当稀土通入速率为60 mL/min时,渗层厚度可达155μm,表面硬度为1275HV0.05,摩擦系数降到0.27,磨损率明显降低。结论钛合金等离子渗氮过程中加入稀土可以有效提高渗速,改善渗氮层硬度,提高材料表面的耐磨性能。     

Enhancing General Corrosion Resistance of Biomedical High Nitrogen Nickel-Free Stainless Steel by Nitric Acid Passivation

A systematic study of nitric acid passivation was investigated to enhance the general corrosion resistance of biomedical high-nitrogen nickel-free stainless steels(HNSs).After passivation,the corrosion rate of HNS could dramatically reduce to 1/20 of the untreated in 37℃0.9 wt% NaCl solutions.Then,the passive film on HNS was analyzed by X-ray photoelectron spectroscopy.It was found that chromium enrichment in the passive film and nitrogen enrichment in the film/metal interface contributed to the improvement in general corrosion resistance of HNS.     

Effect of B2O3 addition on structure and properties of Yb3+/Al3+/B3+-co-doped silica glasses

The homogeneous Yb³⁺/Al³⁺/B³⁺-co-doped silica glasses were prepared via a sol-gel method. The impact of B₂O₃ addition on the physical and optical properties and network structure was systematically studied. The network structure was investigated by the Fourier Transform Infrared (FT-IR), Raman spectra, and Solid State Nuclear Magnetic Resonance (SSNMR). Herein, B₂O₃ addition can continuously decrease the refractive index and density. When B₂O₃ is lower than 2 mol%, B₂O₃ addition can obviously decrease the scalar crystal field parameters, Yb³⁺ asymmetry degree, Yb³⁺ cross-sections, due to the generation of Yb–O–B bonds at the cost of partial Yb–O–Al/Si ones. When B₂O₃ is more than 2 mol%, FT-IR, Raman spectra, and SSNMR results indicate that further increased B atoms prefer to connect with Si and Al rather than Yb. Consequently, the above parameters are basically unchanged. Based on the results, an intuitive model of structure and properties evolution during the substitution of SiO₂ by B₂O₃ has been established.