Composition Effects on the Acidity and Properties of Hydraulic Calcium Phosphate Cements

Hydraulic calcium phosphate cements (HCPC) are considered as the potentially useful materials in a great variety of medical and dental applications. They are biocompatible, bioresorbable, and replaced by new bone when implanted in vivo^[l,2]. However, the use of HCPC might impair the biocompatibility due to low or high pH values during setting. Therefore, the importance of composition on the respective pH profiles of the cement samples during setting and mechanical properties of the HCPC was investigated in this study.     

Low Temperature Sintering and Characterization of YSZ/Al Composite Coatings by Electrophoretic Deposition and Reaction Bonding Process

In practice, low temperature sintering is always the most desirable route to fabricate ceramic composites for industrial manufacturers and an economic way to produce ceramics with unique microstructure for technological applications. Normally the sintering temperature for dense YSZ coating is about 1500℃. Recently many studies have experimentally found that dense ceramic composites can be achieved at a sintering temperature lower by several hundred degrees Celsius for nano-sized powders than for coarse powders^[1-2]. Electrochemical processing is an attractive method for making ceramic films and powders because it offers the advantages of low temperature sintering, low cost and good control of the green forms^[3-4].     

A Study on the Anticorrosion of LD-1 Compound Inhibitor on Reinforcing Steel in Seawater

Corrosion of reinforcing steel in concrete is one of major causes of the loss of durability in marine environment and in those environments contained chloride ions. A number of protective measures have been applied for preventing reinforcement corrosion, and corrosion inhibitors have been developed, which is effective and economical for combating the corrosion problem. This paper shows the evaluation of the effect of LD-1 compound inhibitor, which has been developed in our laboratory, on its anticorrosion action on the reinforcing steel in seawater for the sake of preventing reinforcing steel in concrete in marine environment corrosion.     

羟基磷灰石与牛血清白蛋白相互作用的原位红外光谱研究

应用原位(in situ)全反射红外光谱研究牛血清白蛋白在电化学法制备的羟基磷灰石表面的吸附和成键行为, 探索电化学法制备的HA生物材料/生物环境界面过程和生物相容性的微观本质.     

CaP/壳聚糖复合膜层的电化学共沉积研究

用电化学共沉积方法在医用钛合金表面成功制备了CaP/壳聚糖复合膜层,并用XRD,SEM,FTIR漫反射光谱和XPS等对复合膜层化学组成及结构进行表征.结果表明,加入壳聚糖可使钙磷沉积层结构发生显著变化,将壳聚糖掺入钙磷沉积层,形成CaP/壳聚糖复合物和杂化物.力学实验表明,在钛基底表面未进行表面预处理条件下,CaP/壳聚糖复合膜层与钛基底的结合力高达2.6MPa,比单一CaP电化学沉积层与基底的结合力提高约4倍.文中还对壳聚糖参与表面电沉积反应机理进行了讨论.     

电化学合成金属醇盐的研究

纳米材料在生物、电子、能源、化工等各个领域的应用日益广泛 ,已成为当前研究的热点 [1,2 ] ,纳米材料的制备有多种方法 ,其中溶胶 -凝胶 ( Sol- gel) [3 ] 、醇盐热解、化学气相淀积 ( CVD)等方法所使用的前驱体主要为金属醇盐 .传统化学方法合成金属醇盐是用 MXn[X为 Hal,R,H,NR2 ,N( Si Me3 ) 2等 ]与醇进行交换反应 ,过程复杂 ,且原材料不易得到 ,产率低 ,纯度达不到要求 ,后续分离繁琐 ,所以人们一直努力寻找合成金属醇盐的新方法 .有机电解合成一般在常温常压下进行 ,可通过调节电极电位控制电极反应的方向和速度 .据报道 [4] …     

模拟水中白铜B30耐蚀性影响因素的光电化学研究

用动电位伏安法和光电化学方法对模拟水中白铜B30耐蚀性影响因素进行了研究. 白铜B30表面膜显示p-型光响应, 光响应来自电极表面的Cu₂O层, 在模拟水溶液中表面膜的半导体性质会发生转变, 由p-型转为n-型; 在不同 Cl^－, SO₄^2－浓度的模拟水溶液中, 电位正向扫描时呈现阳极光电流, 电位负向扫描时随着Cl^－, SO₄^2－离子浓度的增加, 光响应由p-型向n-型转变, 阳极光电流峰面积与阴极光电流峰面积之比增大, 耐蚀性能降低; 随着温度的升高, 白铜B30的耐蚀性能降低; 在pH＝7～9之间, 其耐蚀性能随着pH的升高而提高, 当pH＞9时, 其耐蚀性能随着pH的升高呈降低趋势.     

Even-parity states of the Sm atom with stepwise excitation

Two-colour stepwise excitation and photoionization schemes are adopted to study the spectra of high-lying states of the Sm atom. These bound even-parity states are excited with three different excitation paths from the 4f66s6p7DJ (J = 1, 2, 3) intermediate states, respectively. They are probed by photoionization process with an extra photon driving them to the continuum states. In this experiment, 270 states are detected in an energy range from 36160 cm-1 to 42250 cm-1, 109 of which are newly discovered, while the rest of them are confirmed to be the energy levels reported previously. Furthermore, based on the J-momentum selection rules of three excitation paths, a unique assignment of J-momentum for all observed states is determined, eliminating all remaining ambiguities in the literature. Finally, 53 single-colour transitions originating from the scanning laser are also identified. For all the relevant transitions, the information about their relative intensities is also given in the paper.     

Ti表面修饰纳米TiO2膜电极的电催化活性

用电化学合成法在Ti表面修饰一层纳米TiO₂膜,TEM和XRD测试表明晶型为锐钛矿型,晶粒平均尺寸为25nm.用循环伏安法、循环方波伏安法和电解合成法研究了纳米TiO₂膜电极在硫酸介质中的氧化还原行为以及对硝基苯还原的电催化活性。结果表明,纳米TiO₂膜电极具有异相氧化还原催化行为,膜中的Ti(Ⅳ)/Ti(Ⅲ)作为媒质间接电还原硝基苯为对氨基苯酚,收率和电流效率分别达91.6%和95.2%.     

GaN layers with different polarities prepared by radio frequency molecular beam epitaxy and characterized by Raman scattering

GaN layers with different polarities have been prepared by radio-frequency molecular beam epitaxy (RF-MBE) and characterized by Raman scattering. Polarity control are realized by controlling Al/N flux ratio during high temperature AlN buffer growth. The Raman results illustrate that the N-polarity GaN films have frequency shifts at $A_{1}$(LO) mode because of their high carrier density; the forbidden $A_{1}$(TO) mode occurs for mixed-polarity GaN films due to the destroyed translation symmetry by inversion domain boundaries (IDBS); Raman spectra for Ga-polarity GaN films show that they have neither frequency shifts mode nor forbidden mode. These results indicate that Ga-polarity GaN films have a better quality, and they are in good agreement with the results obtained from the room temperature Hall mobility. The best values of Ga-polarity GaN films are 1042 cm$^{2}$/Vs with a carrier density of 1.0$\times $10$^{17}$~cm$^{ - 3}$.