溶胶-凝胶法制备生物活性玻璃陶瓷的研究

采用溶胶-凝胶法制备前驱体粉体,经高温煅烧制备了名义化学组成为MgO4．6,CaO44．9,SiO234．2,P2O516．3,CaF20．5(质量分数)的磷灰石-硅灰石生物活性玻璃陶瓷。用造孔工艺制备了其多孔型材料。通过实验观察、差热和热重分析。体积密度和气孔率的测量,粒度测试、X射线衍射分析。扫描电镜观测,FTIR转换红外光谱分析等方法。研究了玻璃陶瓷前驱体粉末的溶胶-凝胶制备工艺条件,玻璃陶瓷的烧结工艺条件;分析了材料的晶相结构和显微结构。实验结果表明：溶胶-凝胶法可制备出微细的非晶态前驱体粉末,经烧结后玻璃陶瓷主晶相为磷灰石及β-硅灰石。造孔后。多孔型材料具有良好的贯通孔隙结构：微观孔隙约2～3 μm,宏观孔隙约300～400 μm。鉴于其晶相组成及良好的微观结构,通过新型溶胶-凝胶工艺开发的生物活性玻璃陶瓷材料可望被用于骨修复材料及骨组织工程支架材料。     

玻璃基生物水泥的结构研究

利用X射线衍射和扫描电镜研究了玻璃基生物水泥在生理模拟 中羟基磷灰石晶相的形成和长大。应用溶解－析晶理论,阐述了玻璃粉末与调和液,表面活性剂反应,形成HAP的动力学观点,实验结果表明,玻璃基生物水泥在调和液作用下,会形成HAP晶相,在生理模拟液中,随时间的延长,晶体逐渐长大。     

磷灰石晶体化学性质及其环境属性应用

本文在综合评述磷灰石晶体化学特征的基础上,阐述了磷灰石的环境属性.包括孔道效应、表面吸附、离子交换、化学活性、纳米效应、生物相容性等,并简要介绍了磷灰石在核废料处置、水体污染治理、土壤污染治理中的研究情况.     

Ca2Na2La6(SiO4)4(PO4)2O: Eu2+/Eu3+: A visual dual-emitting fluorescent ratiometric temperature sensor

A novel apatite-based UV-excited dual-emitting Ca₂Na₂La₆(SiO₄)₄(PO₄)₂O: Eu²⁺/Eu³⁺ phosphor (CNL: Eu²⁺/Eu³⁺) was designed and successfully synthesized by a solid-state reaction. Compared with previous reports on this family of materials, a structural study based on DFT calculation exhibited a new consequence that the monovalent ions in this system are more inclined to occupy the seven-coordinate cationic sites rather than the nine-coordinate sites. This result was confirmed by the structural refinement and high-resolution transmission electron microscopy (HRTEM) data. Due to the coexistence of Eu²⁺ and Eu³⁺ dopants in the material, under 345 or 392 nm excitation, CNL: 0.02Eu²⁺/Eu³⁺ exhibited a green Eu²⁺ emission band (528 nm) and red Eu³⁺ emission peaks (around 618 nm). The application potential of CNL:0.02Eu²⁺/Eu³⁺ in luminescent thermometry was studied by exploiting the temperature sensitivity of the fluorescent intensity ratio (green/red) at different temperatures. It was found that, under 345 nm excitation, the fluorescent intensity ratio of CNL: 0.02Eu²⁺/Eu³⁺ displayed linear correlation over the temperature range of 298 to 473 K with a high sensitivity of 2.82%K⁻¹. Additionally, the emission color of the CNL: 0.02Eu²⁺/Eu³⁺ sample under UV lamp (254 and 365 nm) excitation showed an obvious change (from green to red) as the temperature increased from 298 to 473 K (from green to red). These results indicated that CNL: Eu²⁺/Eu³⁺ can serve as an excellent visual luminescent ratiometric thermometer. Furthermore, this work provides a novel reference for developing high-performance luminescence temperature-sensing materials.     

Experimental evaluation of a kinetic method for the study of non-catalysed heterogeneous reactions in solid–liquid systems: Leaching of apatite by dilute nitric acid

A method for evaluating the formal reaction order n of a chemical reaction is proposed, based on a kinetic equation describing chemical dissolution of solid particles in a batch reactor. The evaluation is based on the fact that the function expressing the dependence of the conversion, X_B, on the term c_A0ⁿt has the same course for different initial concentrations of the liquid reactant, c_A0 (t denotes time), at constant temperature and ratio of reactants. The measured dependences of the conversion on the time give a function, f_s(X_B), characterizing changes of the solid surface area during the reaction. Minimization of deviations of this function permits the influence of mass transfer between the bulk of the liquid and the solid surface on the measured formal reaction order to be corrected. Knowledge of the value of n and the function f_s(X_B) enables the derived kinetic equation to be integrated numerically and the dependence of the conversion on time to be calculated. A set of experimental data measured during dissolution of natural apatite in dilute nitric acid (0.1–1.5 mol dm⁻³) at 20°C was used for demonstration of the proposed method. © 1998 SCI     

微生物脱除锰矿石中磷的机理研究

以生尘芽杆菌为试验菌种，进行了微生物脱除锰矿石中磷的机理研究。结果表明：锰矿石中磷主要以磷灰石形态赋存；细菌过量摄磷和细胞代谢产酸溶解作用是微生物脱除矿石中磷的根本原因和基本途径。     

用X射线衍射外推法对几种磷矿微结构的测定与研究

采用Ｘ射线衍射仪测定了我国具有代表性的三种品位磷矿的微结构，利用新的外推函数以获得较精确的晶胞参数，同时采用动力学的方法研究了磷矿的反应活性和这些物理特性之间的关系。     

Novel Approach to Tooth Chemistry. Quantification of the Dental-Enamel Junction

The dentin-enamel junction (DEJ) is known for its special role in teeth. Several techniques were applied for the investigation of the DEJ in human sound molar teeth. The electron (EPMA) and proton (PIXE) microprobes gave consistent indications about the variability of elemental concentrations on this boundary. The locally increased and oscillating concentrations of Mg and Na were observed in the junction, in the layer adhering to the enamel and covering roughly half of the DEJ width. The chemical results were compared with the optical profiles of the junction. Our chemical and optical results were next compared with the micromechanical results (hardness, elastic modulus, friction coefficient) available in the world literature. A strong correlation of both result sets was proven, which testifies to the self-affinity of the junction structures for different locations and even for different kinds of teeth and techniques applied for studies. Energetic changes in tooth strictly connected with crystallographic transformations were calculated, and the minimum energetic status was discovered for DEJ zone. Modeling of both walls of the DEJ from optical data was demonstrated. Comparing the DEJ in human teeth with the same structure found in dinosaur, shark, and alligator teeth evidences the universality of dentin enamel junction in animal world. The paper makes a contribution to better understanding the joining of the different hard tissues.     

磷灰石裂变径迹分析法在临清坳陷油气资源评价中的应用

使用磷灰石裂变径迹分析法研究临清坳陷地石油井的地热史,测得了磷灰石裂变径迹年龄和自发裂变投影长度分布随井深的变化,并分析了井的古地温史。     

Lanthanide (=Ce,Pr, Nd and Tb) ions substitution at calcium sites of hydroxyl apatite nanoparticles as fluorescent bio probes: Experimental and density functional theory study

An interesting property of hydroxyl apatite is the ability to undergo cationic and anionic substitution. In this study, nano hydroxyl apatite(nHAp) substituted with four different lanthanide ions(LnO)(Cerium,Praseodymium,Neodymium and Terbium) is prepared by co-precipitation method and characterized by X-Ray Diffraction, Fourier Transform Infrared, Fluorescence and UV‐Visible Spectroscopy and Transmission Electron Microscopy, and Magic Angle Nuclear Magnetic Resonance techniques. Rietveld refinement and computational study using Density Functional Theory has provided information about the effect of LnO substitution on nHAp phase. These studies reveal changes in lattice parameters and preferential calcium sites for LnO substitution in apatite structure. Experimental results have shown that LnO substituted particles have shown an intense fluorescent emission under UV‐Visible excitation. The ability of prepared LnO substituted nHAp particles to inhibit oxidative stress in terms of reduction of hydrogen peroxide is also demonstrated. In- vitro biocompatibility has been assessed via adsorption of human plasma/serum proteins on the surface of nHAp. Adsorption of the protein on nHAp also leads to passivation against corrosion. Particles have shown excellent cell viability and better proliferation of MG-63 cell lines. These results may open new avenues for the development of bioactive materials for bone regeneration and smart fluorescent probes for bio imaging applications.