硼硅酸盐生物活性玻璃在直流电场下的体外矿化性能（英文）

硼硅酸盐生物活性玻璃具有良好的生物活性和骨传导性,但大多数生物活性玻璃表现出非线性降解和矿化行为,矿化性能会随着时间而减缓。电场作为一种外场辅助调节的方法,能够干预玻璃的离子交换和扩散。本研究利用直流电场干预硼硅酸盐生物活性玻璃的体外矿化,加快降解较慢阶段中硼硅酸盐生物玻璃的生物活性。将熔融法制备的成分为18SiO₂-6Na₂O-8K₂O-8MgO-22CaO-2P₂O₅-36B₂O₃的硼硅酸盐生物活性玻璃浸泡在SBF生理模拟液中,施加0～90 m A的电流,研究直流电场对硼硅酸盐生物玻璃降解及体外矿化性能的影响。研究结果表明,施加电场不仅可以提高硼硅酸盐生物活性玻璃的降解率和离子释放量,而且有利于玻璃网络水解和表面羟基化,加速羟基磷灰石的生成。其中失重率比对照组提高了3%～5%,硼和钙的离子释放量分别较对照组提高了2.3～2.9倍和1.9～2.3倍。对硼硅酸盐生物活性玻璃表面结构分析得出,暴露在电场下的样品表面生成了磷灰石层。应用直...     

硼硅酸盐生物活性玻璃在直流电场下的体外矿化性能

硼硅酸盐生物活性玻璃具有良好的生物活性和骨传导性, 但大多数生物活性玻璃表现出非线性降解和矿化行为, 矿化性能会随着时间而减缓。电场作为一种外场辅助调节的方法, 能够干预玻璃的离子交换和扩散。本研究利用直流电场干预硼硅酸盐生物活性玻璃的体外矿化, 加快降解较慢阶段中硼硅酸盐生物玻璃的生物活性。将熔融法制备的成分为18SiO₂-6Na₂O-8K₂O-8MgO-22CaO-2P₂O₅-36B₂O₃的硼硅酸盐生物活性玻璃浸泡在SBF生理模拟液中, 施加0~90 mA的电流, 研究直流电场对硼硅酸盐生物玻璃降解及体外矿化性能的影响。研究结果表明, 施加电场不仅可以提高硼硅酸盐生物活性玻璃的降解率和离子释放量, 而且有利于玻璃网络水解和表面羟基化, 加速羟基磷灰石的生成。其中失重率比对照组提高了3%~5%, 硼和钙的离子释放量分别较对照组提高了2.3~2.9倍和1.9~2.3倍。对硼硅酸盐生物活性玻璃表面结构分析得出, 暴露在电场下的样品表面生成了磷灰石层。应用直流电场可以提高生物活性玻璃的降解及体外矿化性能, 为提升骨修复效果提供了一种新思路。     

辐照对Tb~(3+)掺杂硅酸盐玻璃结构和发光性能的影响

采用高温熔化工艺制备出Tb3+掺杂硅酸盐玻璃,研究了高能辐照对该玻璃结构和发光性能的影响。结果表明,高能辐照后,Tb3+掺杂硅酸盐玻璃的结构发生变化,表现为两个方面:(1)是部分Tb3+离子被氧化为(Tb3+)+离子;(2)是玻璃体内产生大量色心。辐照对Tb3+掺杂硅酸盐玻璃的发光强度影响较大,发光强度随辐照剂量的增大而降低;然而,辐照对Tb3+掺杂硅酸盐玻璃的发光余辉影响较小,发光余辉基本不随辐照剂量的增加而变化。     

Xe/Pb离子辐照对注碳SiO_2发光特性的影响

先用100keV碳离子注入非晶态SiO_2薄膜,再用高能Xe或Pb离子辐照对样品室温下辐照,然后用光谱仪对样品进行分析。实验结果显示,高能Xe或Pb离子的辐照能显著影响样品的发光特性,发光峰的改变与碳的注入剂量、高能离子的种类和能量以及辐照剂量密切相关,发光强度会随着高能离子的辐照剂量增加而变化,具有较大电子能损值的入射离子能更高效的导致材料的发光特性改变。发光特性的改变与薄膜内部微结构的变化有关,入射离子对应的电子能损大将会造成更大的材料损伤,从而能更显著的影响样品的发光。对离子辐照导致薄膜发光峰演化与薄膜微结构改变的关联进行了简单讨论。     

伽马辐照对掺镱硅酸盐玻璃光学性能的影响

采用传统的高温熔融法熔制了一系列掺镱硅酸盐玻璃, 并测试了这些样品经总剂量为5 kGy的钴-60伽马射线辐射源辐照前后的吸收谱、荧光谱和上转换发光光谱. 实验结果表明: 辐致暗化效应导致玻璃样品在400 nm附近出现一个非常强的宽吸收带, 其尾端可延伸至近红外区.经辐致损耗谱分析可知, 部分Yb³⁺离子在辐照过程中通过俘获电离自由电子转变成了Yb²⁺离子, 导致掺杂样品的辐致损耗明显比基质材料的要大. 在960 nm LD泵浦下辐照过的样品荧光强度、上转换发光强度及荧光寿命均有所下降, 且在476 nm附近出现了氧缺陷ODC(Ⅱ)的荧光.室温下辐照过的样品在荧光测试过程中温度明显升高并出现漂白现象.     

Ni10+离子辐照Ni-Mo-Cr合金微观结构演变和硬化的研究

室温下对钍基熔盐堆(TMSR)中候选合金结构材料Ni-Mo-Cr合金进行了能量为132MeV的Ni 10+离子辐照研究,辐照剂量分别为1dpa、3dpa和9dpa。X射线衍射仪(XRD)分析显示离子辐照后Ni-Mo-Cr合金发生晶格畸变,维氏显微硬度的测量结果表明高剂量的离子辐照造成Ni-Mo-Cr合金的硬化,这主要归因于辐照导致材料内部形成大量缺陷。当辐照剂量为9dpa时,维氏硬度测试结果表明损伤的峰值出现的深度介于8.1~12.3μm之间,此结果与理论计算相吻合。     

低介电高硼硅酸盐玻璃的性能研究

以硼硅酸盐玻璃为基础玻璃系统,研究了超高硼含量区间,硼硅酸盐玻璃结构和性能的变化规律。通过红外光谱分析了硼硅酸盐玻璃在不同B2O3含量的情况下的结构变化,测试了玻璃的热膨胀系数、转变温度、软化温度和高温粘度。研究结果表明,高硼玻璃难以析晶;随着B2O3含量的增加,玻璃结构中[BO4]、[BO3]数量增多,其中以[BO3]为主;玻璃的热膨胀系数呈现出S型变化,转变温度和软化温度都逐渐减小;介电常数与介电损耗都出现极小值,过量的B2O3会起到反作用;此外B2O3起到降低高温粘度的作用,但降低作用有限。     

含锶硼硅酸盐生物玻璃的降解性能及体外生物活性

研究了含锶硼硅酸盐玻璃的体外生物活性和降解性。采用熔融法制备不同锶含量(SrO含量为0、2%、4%、6%、8%、10%、12%(摩尔分数))的硼硅酸盐生物玻璃粉末,粒径范围为150～300μm。将各组玻璃样品浸泡在0.02mol/L的K2HPO4溶液中,置于37℃恒温条件下,进行体外生物矿化反应。通过对反应样品的质量损失以及浸泡液pH值进行测定,并用XRD、FTIR以及SEM对反应过程和反应后产物进行表征。结果表明,含锶的硼硅酸盐玻璃在体外生物矿化反应中被生物降解,并转化为含锶羟基磷灰石,具有很好的生物活性和降解性;同时也观察到玻璃中引入锶元素后,在一定程度上控制玻璃的降解速度,进而控制硼的溶出速度,从一定程度上避免硼溶出速度过高可能带来的风险;ICP的结构也表明,当SrO为6%(摩尔分数),样品中硼元素溶出的速度最低。因此,用锶的含量可控制硼硅酸盐玻璃的降解速度,这种方法将在组织工程领域具有广阔的应用前景。     

含锶硼酸盐基生物玻璃经晶化处理后对其溶解性能及体外生物活性的影响

通过对含锶硼酸盐基玻璃进行微晶化处理,以考察该玻璃由玻璃态转化为晶态时体外生物活性和降解性的改变。采用熔融法制备不同锶含量(n(SrO)=0、2%、6%)的硼硅酸盐生物玻璃,然后在700℃/4h条件下微晶化处理,分别获得微晶化前后的试样。将各组玻璃及微晶化的样品浸泡在类似于生理模拟液的0.02mol/L的K2HPO4溶液中(以1g玻璃对应100mL浸泡液的比例),置于37℃恒温条件下,进行体外生物矿化反应。用XRD和FT-IR对反应后产物进行表征,并测定不同浸泡时间下样品的质量损失率以及浸泡液的pH值。结果表明,微晶化处理前后的含锶的硼硅酸盐玻璃试样在浸泡实验中都可以转化成含锶羟基磷灰石,即微晶化后的试样仍然具有体外生物活性;并且微晶化后试样的离子溶出速度能够减缓,降低了原玻璃相对骨组织生长来说的较高的降解速度,可以更加匹配骨组织生长的周期。因此,微晶化处理硼硅酸盐玻璃可实现对降解速度的调控,使该微晶化的生物玻璃有可能在骨组织修复中得到临床应用。     

Pb2+对掺杂硼硅酸盐玻璃中CsPbBr3钙钛矿量子点发光性能的影响(英文)

硼硅酸盐玻璃包覆钙钛矿CsPbBr₃量子点(PQDs@glass)能够大幅提高PQDs的稳定性,使其在LED照明和显示技术中拥有广泛的应用空间。然而,玻璃包覆的同时也导致了PQDs发光强度与量子产率降低。本工作为提高其发光强度探讨了热诱导温度及Pb²⁺的含量对PQDs@glass结构的影响,当热诱导温度为460℃,Pb²⁺浓度为6 mol时,其发光强度最高。研究发现,Pb²⁺浓度的增加会导致玻璃网状结构的致密化,改变玻璃组分的扩散行为,影响PQDs的析晶过程,导致PQDs@glass发光强度的变化。本工作得到量子产率高达95.6%的PQDs@glass,并实现了硼硅酸盐玻璃基质内PQDs的尺寸可控制备。结果表明,PQDs尺寸分布在10nm左右,超过86%的颗粒尺寸在6～14 nm内,且具有优越的稳定性,经历10次室温至200℃热循环后,发光强度仍能保持初始强度的98.9%。最后,为了验证其在LED照明及显示领域的应用,将制备的量子点微晶玻璃粉料与二甲基硅氧烷(PDMS)混合,得到的LED器件性能优异...     

Radiation hardness of the electrical properties of carbon nanotube network field effect transistors under high-energy proton irradiation

The effect of high-energy proton irradiation on the physical properties of carbon nanotubes (CNTs) was investigated. The focus of the study was on the electrical properties of single-walled carbon nanotube (SWNT) network devices exposed to proton beams. Field-effect transistors (FETs) of network type were fabricated using SWNTs and were then irradiated by high-energy proton beams of 10-35?MeV with a fluence of 4 × 10(10)-4 × 10(12)?cm(-2) that are comparable to the aerospace radiation environment. The electrical properties of both metallic and semiconducting CNT network FET devices underwent no significant change after the high-energy proton irradiation, indicating that the CNT network devices are very tolerant in proton beams. Raman spectra confirm the proton-radiation hardness of CNT network FET devices. The radiation hardness of CNT network FET devices promises therefore the potential usefulness of CNT-based electronics for future space application.     

Effects of proton irradiation on the microstructure and mechanical properties of Amosic-3 silicon carbide minicomposites

One dimensional Amosic-3 silicon carbide fiber reinforced silicon carbide matrix composites (SiC_f/SiC minicomposites) prepared by chemical vapor infiltration were irradiated with 2.8 MeV proton ions. The ion fluences were 1.0 × 10¹⁷ and 1.5 × 10¹⁷ cm⁻² at room temperature and 300 °C, respectively. The microstructure and mechanical properties were investigated before and after proton irradiation. Raman spectra showed no evident change in Amosic-3 fibers regardless of irradiation temperature, which is confirmed by high resolution transmission electron microscopy observation. Pyrolytic carbon interphase showed slightly expansion after 300 °C irradiation, however, no microstructure changes were observed in SiC matrix. Moreover, it can be deduced that no irradiation induced changes in mechanical properties were observed after present proton irradiation.     

Mössbauer studies of iron doped poly(methyl methacrylate) before and after ion beam modification

High-energy MeV ions from accelerators are known to produce drastic modifications in polymers. The typical effects include chain scissions, crosslinks, molecular emission and double bond formation. Poly(methyl methacrylate) was doped with Fe(III) and irradiated with 95 MeV O⁷⁺ ions.⁵⁷Fe-Mössbauer studies were done on the doped samples before and after irradiation. Before irradiation, no Mössbauer absorption was observed. The irradiated samples showed a good Mössbauer absorption, which seems to indicate that there is a significant interaction between the metal ion and the polymer matrix. Two possibilities exist at these doses (～ 22 × 10¹² ions/cm): Fe(III) ions may be bridging the various polymer segments through crosslinking or amorphization of the sample leading to Fe-C bonding. Studies of FTIR, conductivity and glass transition temperatures on these samples support these observations.     

Proton and alpha particle induced changes in thermal and mechanical properties of Lexan polycarbonate

The thermal and mechanical properties of Lexan polycarbonate (PC) irradiated by 15 MeV proton and 40 MeV alpha particles with different fluencies have been investigated. The thermal decomposition temperature, thermal activation energy of decomposition, tensile strength, fracture strain, Young's modulus and average molecular weight of PC decreased after irradiation. The infrared spectroscopic results showed breakage of the carbonate site in PC after irradiation. The average surface roughness value of PC increased and it showed pores formation after irradiation. These changes in thermal and mechanical parameters were due to chain scission of C–O bond in PC after irradiation which is confirmed from infrared spectroscopic results. It was also showed that 40 MeV alpha particles induce more changes in thermal and mechanical properties of PC when compared to that of 15 MeV proton.     

Effect of ion irradiation in an Al90Fe2Ce8 metallic glass

Here the irradiation effect of an AlFeCe metallic glass under nitrogen ions was investigated. Ion irradiation induced crystallization can be observed in the studied metallic glass. The surface morphologies have been also examined by atomic force microscopy prior to and after ion irradiation. It is found that the surfaces have been smoothened after ion irradiation. The nanohardness and Young’s modulus of metallic glass increase after ion irradiation, which can be attributed to the formation of crystalline phases. The results obtained here clearly suggest that ion irradiation can be a useful method to tailor the microstructure and mechanical properties of metallic glasses.     

Ion irradiation hardening of C60 thin films

The nanoindentation technique is used to measure the hardness and the Young’s modulus of ion irradiated C₆₀ films, 70 nm thick, deposited on a Silicon substrate. An increase of hardness from 1.3 GPa for the pristine sample to 10 GPa after irradiation with 800 keV Bi⁺ and N²⁺ ions was observed. The Young’s modulus also increases from 60–150 GPa after the irradiation. The results are discussed in terms of the damage and amorphization produced as consequences of the electronic and nuclear energy transference due to the irradiation.     

Microstructuring of UV-transparent functionalised films on glass by excimer laser irradiation

KrF excimer laser irradiation was used to remove organic moieties from UV-transparent films of organosilanes on borosilicate glass. High-resolution patterns with different functional groups on glass were obtained by a combination of laser modification and silanisation steps. The local material modification near the ablation threshold of glass was investigated by white light interference microscopy. Change in chemical properties of irradiated surface areas were studied by fluorescence microscopy after an appropriate dying of exposed samples. From the results, the domination of thermo-chemical effects induced by the laser irradiation is derived. Finally, an example is given how the patterned organosilane films can be applied to influence cell growth on glass.     

Synthesis of nanoscale copper nitride thin film and modification of the surface under high electronic excitation

Nanoscale (approximately 90 nm) Copper nitride (Cu3N) films are deposited on borosilicate glass and Si substrates by RF sputtering technique in the reactive environment of nitrogen gas. These films are irradiated with 200 MeV Au15+ ions from Pelletron accelerator in order to modify the surface by high electronic energy deposition of heavy ions. Due to irradiation (i) at incident ion fluence of 1 x 10(12) ions/cm2 enhancement of grains, (ii) at 5 x 10912) ions/cm2 mass transport on the films surface, (iii) at 2 x 10(13) ions/cm2 line-like features on Cu3N/glass and nanometallic structures on Cu3N/Si surface are observed. The surface morphology is examined by atomic force microscope (AFM). All results are explained on the basis of a thermal spike model of ion-solid interaction.     

Study of microhardness and electrical properties of proton irradiated polyethersulfone (PES)

Polyethersulfone (PES) films were irradiated with 3 MeV proton beams in the fluence range 10¹³–10¹⁵ ions/cm². The radiation induced changes in microhardness was investigated by a Vickers’ microhardness tester in the load range 100–1000 mN and electrical properties in the frequency range 100 Hz-1 MHz by an LCR meter. It is observed that microhardness of the film increases significantly as fluence increases up to 10¹⁴ ions/cm². The bulk hardness of the films is obtained at a load of 400 mN. The increase in hardness may be attributed to the cross linking effect. There is an exponential increase in conductivity with log frequency and the effect of irradiation is significant at higher fluences. The dielectric constant/loss is observed to change significantly due to irradiation. It has been found that dielectric response in both pristine and irradiated samples obey the Universal law and is given by ɛ ∝ f ⁿ⁻¹. These results were corroborated with structural changes observed in FTIR spectra of irradiated samples.     

Analysis of organometallics dispersed polymer composite irradiated with oxygen ions

Thin films of polymethyl methacrylate (PMMA) were synthesized. Ferric oxalate was dispersed in PMMA films. These films were irradiated with 80 MeV O⁶⁺ ions at a fluence of 1×10¹¹ ions/cm². The radiation induced changes in electrical conductivity, Mössbauer parameter, microhardness and surface roughness were investigated. It is observed that hardness and electrical conductivity of the film increases with the concentration of dispersed ferric oxalate and also with the fluence. It indicates that ion beam irradiation promotes (i) the metal to polymer bonding and (ii) convert the polymeric structure into hydrogen depleted carbon network. Thus irradiation makes the polymer harder and more conductive. Before irradiation, no Mössbauer absorption was observed. The irradiated sample showed Mössbauer absorption, which seems to indicate that there is significant interaction between the metalion and polymer matrix. Atomic force microscopy shows that the average roughness (R _a) of the irradiated film is lower than the unirradiated one.