a—TCP／TTCP牙根管充填材料

a－TCP／TTCP骨水泥具有良好的水化硬化特性，符合临床需要的凝结时间和抗压强度，其水化产物主要为羟基磷灰石（HAP），以a－TCP／TTCP骨水泥作为牙根管充填材料，通过体外实验、动物实验，结合组织形态学及扫描电镜观察，检测a－TCP／TTCP牙根管充填材料的组织相容性，并动态观察根尖闭合情况及根尖周组织修复过程。结果表明，材料优良的生物相容性，在牙根管内可继续水化硬化，而且能引导根尖钙化组织沉积，封闭根尖孔，形成骨性结合，并促进根尖周组织愈合。     

α -TCP/TTCP牙根管充填材料

α TCP/TTCP骨水泥具有良好的水化硬化特性 ,符合临床需要的凝结时间和抗压强度 ,其水化产物主要为羟基磷灰石 (HAP)。以α TCP/TTCP骨水泥作为牙根管充填材料 ,通过体外实验、动物实验 ,结合组织形态学及扫描电镜观察 ,检测α TCP/TTCP牙根管充填材料的组织相容性 ,并动态观察根尖闭合情况及根尖周组织修复过程。结果表明 ,材料具有优良的生物相容性 ,在牙根管内可继续水化硬化 ,而且能引导根尖钙化组织沉积 ,封闭根尖孔 ,形成骨性结合 ,并促进根尖周组织愈合     

多巴胺载入对磷酸钙骨水泥性能的影响及体外生物学评价

本实验利用具有良好生物相容性和强黏附性能的多巴胺(dopamine,DA)提高磷酸钙骨水泥(calcium phosphate cement,CPC)的抗压强度,采用X射线衍射仪、X射线光电子能谱仪、万能材料力学试验机和场发射扫描电镜研究载多巴胺磷酸钙骨水泥(DA-CPC)的理化性能;将DA-CPC与成骨细胞(MC3T3-E1)体外共培养,以荧光显微镜观察细胞形貌,并进行Alamar Blue和碱性磷酸酶检测,研究DA载入后对成骨细胞增殖和分化的影响。结果表明:DA载入CPC中可发生自聚合形成聚多巴胺,促进CPC中的α-TCP和DCPD的溶解与转化,并不改变最终水化相成分;显著地提高CPC的抗压强度;DA的载入有利于成骨细胞的早期粘附和增殖,并不影响其分化。本实验表明载入DA的CPC具有良好的生物相容性,载入DA为提高CPC的抗压强度提供了一条可能的途径。     

HA／β-TCP双相磷酸钙陶瓷材料的生物学性能研究

研究了双相磷酸钙陶瓷在SBF中类骨磷灰石的形成，采用小鼠骨骼肌母细胞C2C12细胞系和HA／β-TCP复合培养，通过细胞增殖实验，电镜和荧光染色法观察并实施动物肌肉内植入实验，得出：材料在SBF中浸泡后有利于类骨磷灰石的沉积。细胞在HA／β-TCP支架材料上生长良好。对HA／β-TCP进行细胞毒性评价，与阴性对照组比较，样品不抑制细胞增殖，表现出良好的生物相容性。HA／β-TCP支架材料能促进细胞的增殖。动物实验表明，在体内HA／β-TCP有很好的骨形成能力。因此，实验制备的HA／β-TCP支架材料有良好的生物学性能。     

PHBV微球／磷酸钙骨水泥复合材料研究

采用在磷酸钙骨水泥中添加一定量的PHBV微球来制备在初期有较高的抗压强度，而后随着PHBV微球的降解，在磷酸钙骨水泥基体中形成三维孔隙结构的PHBV微球／磷酸钙骨水泥复合材料。选用的骨水泥的固相成分以α-TCP为主，液相成分为NaH2PO4／Na2HPO4、KH2PO4/K2HPO4缓冲溶液，PHBV微球直径为100μm～300μm，主要研究不同的固化液，固液比以及PHBV微球添加量对PHBV／磷酸钙骨水泥复合材料抗压强度等性能的影响，制备出凝固时间在15min-30min，具备一定可注射性，抗压强度达到10MPa～30MPa的PHBV微球／磷酸钙骨水泥复合材料。最终制备的PHBV微球／磷酸钙骨水泥复合材料能够满足骨修复材料的要求。     

壳聚糖微球/磷酸钙骨水泥复合材料动物体内植入实验研究

将壳聚糖微球/磷酸钙骨水泥复合材料植入兔股骨髁内,进行大体观察和X光片观察,并分别在植入兔股骨髁内8、16和24周,取出样本进行组织学观察和环境扫描电镜观察,研究植入材料与骨组织界面的结合状况和材料在动物体内的降解过程及新骨重建生成状况,探索材料在体内的降解机制和成骨机制.结果表明:壳聚糖微球/磷酸钙骨水泥在骨组织内具有良好的生物相容、组织相容性和和骨结合性,能够与自然骨组织形成紧密的骨性结合.材料在体内具有较快的降解速度,植入24周后,80%以上材料降解,被新生骨组织替代,该材料还具有良好的可塑性和临床操作性,是一种很有临床应用前景的骨修复材料.     

组织工程化三维仿骨支架重建股骨头坏死区研究

首先研制出具有取向性类骨结构的β-TCP三维仿骨支架,经过仿生类骨处理和组织工程化后,植入犬的股骨头坏死区,30周后取出股骨头进行分析研究.与此同时开展了几种支架材料重建股骨头坏死区的力学性能分析和模拟.结果显示,具有取向性类骨结构的β-TCP三维仿骨支架具有很好的生物相容性和力学相容性.动物实验研究表明:组织工程化三维仿骨支架诱导生长出新的骨小梁,并伴有β-TCP降解,这为修复或重建股骨头局部坏死区提供了一种有希望的新途径.     

外科植入物用TC20(Ti-6Al-7Nb)钛合金研究与应用

对TC20合金力学性能、生物学性能和临床应用进行了研究.合金棒材成分、组织与性能满足国际标准ISO5832要求;材料的生物学性能实验证明合金具有良好生物相容性,并能和骨组织形成良好的骨整合;近40例的临床应用表明疗效良好.     

二水硫酸钙/β-磷酸三钙/聚乳酸复合材料的制备及性能研究

本实验主要研究二水硫酸钙(CS)/β-磷酸三钙(β-TCP)/聚乳酸(PLA)复合材料的制备和性能。先将CS和β-TCP共混球磨,然后用溶液共混法制得CS和β-TCP总的质量分数为20%的聚乳酸三相复合材料,并制成2 mm×5mm×5 mm的片状颗粒。复合材料的抗拉强度测试结果表明,在CS与β-TCP总的质量分数不变的条件下,随着CS添加量的增多和β-TCP添加量的的减少,复合材料的抗拉强度呈下降趋势。经Tris溶液浸泡后,其质量由于降解而缓慢减少,并随着CS相对含量的增加,复合材料的质量减少速率逐渐减小。SEM结果显示,浸泡后的材料表面出现蚀孔与沉积现象。体外细胞培养结果表明,细胞可以在复合材料表面粘附和增殖,其细胞相容性与聚乳酸相当。实验结果表明,所得到的复合材料力学性能能够达到骨内固定材料使用的要求,具有良好的生物相容性,并且降解速度可调,具有作为新型可降解骨内固定材料使用的潜在可能。     

多孔镁表面生物活性β-TCP涂层的制备及其细胞相容性研究

采用化学沉积法在镁支架表面制备生物活性的β-TcP(磷酸三钙陶瓷)涂层,利用X射线衍射,扫描电子显微镜研究β-TCP涂层的相结构和表面形貌.并对表面改性的镁支架与类成骨细胞UMR106的体外生物相容性进行了详细研究.结果表明,表面改性后的镁支架浸提液细胞毒性为1级,即无细胞毒性;材料浸提液无细胞DNA毒性,对细胞周期无改变,也无异倍体细胞出现.实验结果证明,表面改性后的多孔镁具有良好的细胞相容性,是一种很有前景的新型骨组织工程支架材料.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.