激光脉冲能量对四面体非晶碳薄膜的结构及血液相容性的影响

采用脉冲激光方法制备了sp3/sp2不同比率的四面体非晶碳薄膜.利用拉曼光谱、紫外可见光谱等材料表征方法, 研究了脉冲激光能量对四面体非晶碳薄膜的微结构及血液相容性的影响.结果表明:脉冲激光能量显著影响四面体非晶碳薄膜中sp3/sp2的比率,调控单脉冲激光能量范围为150～250mJ,可使薄膜的光学带隙从1.41～2.44eV发生变化.血小板粘附实验和动态凝血实验表明制得的薄膜具有优良的血液相容性.分析了四面体非晶碳薄膜的抗凝血机理.     

a—C：H薄膜组成及结构

含氢非晶碳(a-CH)薄膜主要由SP3C、SP2C和H 3种"元素"组成,在它们的三元相图中,a-CH薄膜具有特定的组成区域.由于IR分析法对SP3C/SP2C分析存在着系统误差,因而导致所得结构偏离该组成域.通过对IR法的结果分析发现,SP3C含量偏高,SP2C含量偏低;a-CH薄膜中SP2C主要以非质子化形式存在,其含量可高达67%;质子化的SP2C仅占Sp2C总量的10%左右.a-CH薄膜是受到较高约束的空间立体网络结构.     

稀土铈掺杂的非晶碳薄膜的微结构及其抗凝血性能的影响

采用射频磁控溅射方法制备了稀土元素铈掺杂的非晶碳薄膜．通过改变稀土铈的掺杂量，利用拉曼光谱，紫外可见光谱等方法，研究了稀土元素铈掺杂的非晶碳薄膜的微结构、成分、形貌及亲水性的影响。结果表明：在非晶碳薄膜中掺入稀土元素铈后，薄膜中sp^3／sp^2的比率显著发生变化，薄膜的疏水性明显提高。血小板粘附实验表明掺杂稀土铈有利于改变非晶碳薄膜的抗凝血性能，适当的掺杂量能使薄膜的血液相容性得到优化。分析了稀土元素铈对材料的血容性能的影响机制．     

Ti(Ta)O2薄膜的表面形貌对血管内皮细胞生长量影响的研究

采用磁控溅射合成不同Ta含量的系列Ti(Ta)O2薄膜.利用扫描电子显微镜(SEM)、原子力显微镜(AFM)对薄膜的表面形貌进行表征.并对薄膜表面进行人脐静脉内皮细胞(HUVEC)种植试验以评价薄膜材料的表面形貌对细胞组织相容性的影响.结果表明,细胞在不同Ta含量的Ti(Ta)O2薄膜表面因表面形貌的不同具有明显不同的粘附、增殖和生长行为.薄膜表面适当的粗糙度有利于细胞的贴附、生长和增殖.该研究指出,通过控制材料表面改性层的特征,可改善其表面细胞生物学行为,并可提高薄膜材料表面生物相容性.     

非晶金刚石膜在口腔医学材料中的应用

采用带过滤的阴极真空等离子电弧镀膜技术,对口腔牙用聚甲基丙烯酸甲酯(PMMA)树脂及纯钛材料进行了表面镀覆非晶金刚石膜的改性处理,获得了镀覆非晶金刚石膜的PMMA树脂和镀覆非晶金刚石膜的纯钛口腔牙用材料。通过细胞培养和动物实验,考察了非晶金刚石膜的生物相容性。采用HA-1型涂层附着力划痕试验仪研究了非晶金刚石膜与PMMA树脂和与纯钛的结合力及镀覆非晶金刚石膜PMMA树脂和镀覆非晶金刚石膜纯钛的耐磨性能。在人工唾液中模拟口腔环境进行电化学分析测试了镀覆非晶金刚石膜纯钛材料的耐腐蚀性能。借助SEM观察了镀覆非晶金刚石膜纯钛材料的表面形貌。实验结果显示:非晶金刚石膜细胞毒性评级为0级,溶血率为3.08%,短期全身毒性试验为阴性;PMMA树脂经极化预处理后可镀覆结合力为(10.86±0.79)N的非晶金刚石膜;镀覆非晶金刚石膜纯钛表面自腐蚀电位和过钝化电位正移。表明非晶金刚石膜作为生物材料,其生物安全性、耐腐蚀性及镀膜结合强度达到口腔医用材料的要求。     

MPCVD法在镍基底上低温沉积石墨烯的研究

石墨烯是具有优异性能的二维碳材料。采用微波等离子体化学气相沉积法（MPCVD）,以甲烷和氢气为气源,在镍基底上生长石墨烯薄膜,沉积温度在650℃附近。对制备石墨烯薄膜用金相显微镜、原子力显微镜观察其覆盖率和表面形貌,用拉曼光谱仪对沉积薄膜的层数、质量和非晶碳含量进行表征。研究结果表明氢等离子体对表面碳键有明显刻蚀,产生空隙和晶界缺陷;甲烷含量的升高提高了膜层的覆盖率,也促进非晶碳的生成;气压较低时膜层覆盖率较低,较高时膜层厚度明显增加。     

氧化钛薄膜表面羟基活化能力及对生物相容性的影响

采用非平衡磁控溅射法制备了3种不同结构的TiO2薄膜,对所得TiO2薄膜运用碱处理方法进行表面处理,期望在材料表面获得羟基活性基团.运用X射线衍射(XRD)研究了薄膜的表面结构.利用傅里叶红外技术(FTIR)和X射线光电子能谱仪(XPS)等手段对活化处理前后样品表面的羟基基团进行检测,并对活化前后样品进行了内皮细胞培养和血小板黏附实验.结果表明,运用碱处理方法,可以在锐钛矿型以及金红石与锐钛矿的混晶结构TiO2薄膜表面形成活性羟基基团;相比于金红石型TiO2薄膜,混晶结构和锐钛矿型具有较好的羟基活化能力.生物相容性实验表明,碱活化处理后样品表面细胞生长数目多于活化前样品,血小板黏附数量少于活化前样品,表面活性基团的存在有利于提高TiO2薄膜材料的生物相容性.此外,影响TiO2薄膜表面生物活化性能的因素进行了初步探讨.     

炭纤维生物膜的形成机制Ⅰ. 炭纤维表面特性对微生物固着化的影响

采用对比方法,借助化学分析、表面形态分析及生物相容性表征技术等系统地研究了以活性炭纤维、表面改性活性炭纤维作为细胞固着化载体的表面特性及对微生物固着的影响.重点考察了纤维表面官能团、比表面积、润湿性等表面特性对微生物固着化的影响.研究结果表明:(1)炭纤维表面的吸附特性对微生物的初期固着起着重要的作用,具有高比表面积的活性炭纤维更易于微生物固着并挂膜.(2)炭纤维表面润湿性与某些酸性官能团的适量增加,有益于载体表面微生物的固着.(3)炭纤维尤其是活性炭纤维较市售有机高分子材料具有更加优异的生物相容性,前者的微生物固着化速率是后者的4倍～16倍.     

宁波材料所金属掺杂DLC复合薄膜材料体系研究取得系列进展

正类金刚石薄膜材料(diamond-like carbon,简称DLC)作为一类非晶碳膜材料的统称,主要由sp3键(金刚石相)和sp2键(石墨相)的三维交叉网络混合而成,依制备方法不同可含有一定量氢,具有高硬度、低摩擦系数、高红外透光性、良好化学惰性和生物相容性等诸多优异性能,在海洋、航空航天、生物医用、微机电、汽车等领域具有广阔应用前景。     

Ti-O/Ti-N复合薄膜的离子束合成及人工心脏瓣膜材料表面改性研究

采用离子束增强沉积（ＩＢＥＤ）等方法在热解碳、钛及钴合金等人工心脏瓣膜材料表面制备Ｔｉ－Ｏ、Ｔｉ－Ｎ及其复合薄膜。对薄膜的成分、结构进行了研究，测定了材料的电阻率，对薄膜材料的血液相容性和力学性能进行了系统的研究。结果表明：合成薄膜具有优于热解碳的血液相容性和力学性能，提出了材料的血液相容性机理模型。     

Phase Formation During Nonisothermal Decomposition of the Freeze-Dried Bi:Pb:Sr:Ba:Ca:Cu = 1.8:0.4:1.8:0.2:1.2:2.0 Complex Nitrate Powder

Nitrate powder with cation composition Bi:Pb:Sr:Ba:Ca:Cu = 1.8:0.4:1.8:0.2:1.2:2.0 was obtained by spray-frozen, freeze-drying technique. Samples of the nitrate precursor powder were placed in a heated furnace (heating rate 100°C/min) and extracted in air when temperature of the powdered samples attained values of 439, 495, 550, 600, 640, 647, 717, 766, 814, and 850°C. Samples have been investigated by X-ray diffraction analysis. The obtained data allow us to propose and discuss phase formation and decomposition processes and reactions that occur in non-isothermal conditions at different temperatures during thermal decomposition of the nitrate powder.     

Flash-lamp-pumped Ho:Tm:Cr:YAG and Ho:Tm:Er:YLF lasers: modeling of a single, long pulse length comparison

Two methods of producing the long pulse lengths that promote efficient extraction of energy from low-gain, quasi-four-level lasers are analyzed. A long pulse length output can mitigate laser-induced damage effects and can be generated in quasi-four-level lasers by two disparate methods. One method utilizes Q-switching techniques in resonators designed to extend the pulse length and another utilizes the first pulse in a relaxation oscillation pulse train. Models for quasi-four-level lasers are derived here taking into account the nonnegligible thermal population of the lower laser level. Closed-form expressions are derived for both modes of operation of quasi-four-level laser systems so the parametric dependencies of both forms of operation become obvious, allowing facile comparison. In addition, a combined absorption and quantum efficiency, germane for flash-lamp pumping, is calculated for both Cr and Er sensitizers. Although the former has the advantage of broad absorption bands, the latter has the advantage of a quantum efficiency approaching 3.     

Flash-lamp-pumped Ho:Tm:Cr:YAG and Ho:Tm:Er:YLF lasers: experimental results of a single, long pulse length comparison

Flash-lamp-pumped, room-temperature Ho:Tm:Cr:YAG and Ho:Tm:Er:YLF are compared for single but long pulse operation, with pulse lengths of approximately 1.0 mus. Under similar operating conditions in normal-mode operation, a slope efficiency of 0.0331 was observed for Ho:Tm:Er:YLF compared with 0.0047 for Ho:Tm:Cr:YAG. For Q-switched operation, Ho:Tm:Er:YLF yielded a slope efficiency of 0.0075. In comparison, a slope efficiency of 0.0012 was obtained for Ho:Tm:Cr:YAG. Two methods of producing long pulse lengths are compared: pulse selection of normal-mode relaxation oscillations and Q-switching in a long resonator. Theoretical models developed in a companion paper for normal-mode relaxation oscillations and Q-switching in quasi-four-level solid-state lasers are in agreement with the experimental results.     

Electroluminescence of (Zn:Cd)S:Mn:Sm:Cl phosphors

The effect of field strength and frequency on electroluminescence brightness has been investigated for the binary systems (Zn:Cd)S:Mn:Cl and (Zn:Cd)S:Mn:Sm:Cl. The voltage dependence of the time averaged electroluminescent brightness shows the relation B = B_o exp ($\text{?}\text{C}\text{√}\text{v}$ and holds good over a wide range of frequencies, thus indicating that the mechanism of excitation is acceleration collision. The dependence of constants B_o and C on frequency of the applied field shows that the brightness of the electroluminescence is found to saturate at higher frequencies. It has been observed that EL peak emissions for these phosphors were found to be at 560 nm and 580 nm.     

Optical and EPR spectroscopy of Zn:Cr:ZnSe and Zn:Fe:ZnSe crystals

Optical and EPR characterization of Cr and Fe doped ZnSe crystals annealed in Zn vapor revealed a strong bleaching of the divalent state of transition metal ions. Photo induced EPR kinetics were studied in 20–80 K temperature range. Analysis of time-dependent data reveals Cr¹⁺ signal rise time decreases with increasing temperature. The non-exponential decay of Cr¹⁺ concentration were analyzed using Auger-type recombination process. The photoluminescence quantum yield of Cr²⁺ ions at ⁵E(D) → ⁵T₂(D) mid-IR transition excited via chromium ionization process was measured to be close to 100%.     

Growth of YLF:Yb:Tm:Nd for optical applications

The focus of this study is the behavior of Tm, Yb and Nd ions in the LiYF₄ (YLF) crystal. One YLF crystal was successfully grown by the Czochralski method; it was doped with 20 mol% Yb, 1.3 mol% Nd and 0.05 mol% Tm. The segregation coefficients of the dopants and lattice parameters were determined. The spectroscopic properties of samples with different amounts of Nd were obtained from absorption and emission studies.