快速冷却条件下银的比热及玻璃化过程的分子动力学模拟

本文采用以嵌入原子模型为基础的分子动力学方法对液态银快速冷却条件下的比热及玻璃化过程进行了模拟，得到了银的比热及其与温度的关系．同时，对快速冷却条件下银的结构特性以及动力学特性进行模拟和分析，结果表明在所模拟的冷却速率下，银在从 １２００ Ｋ冷却到 １０００ Ｋ的过程中发生了玻璃化转变，其玻璃化温度在 １０００ Ｋ左右．     

ZnO纳米棒的低温溶液法制备、光电特性研究及其在有机/无机复合电致发光中的应用

利用水热法制备了垂直于衬底的定向生长的ZnO纳米棒,利用扫描电子显微镜及光致发光的方法对其形貌及光学特性进行了表征,利用场发射性能测试装置对ZnO纳米棒的场发射性能进行了测试.结果表明:利用水热法在较低的温度(95 ℃) 下生长了具有较好形貌和结构的ZnO纳米棒,并表现出了较好的场发射特性,当电流密度为1 μA/cm²时,开启电场是2.8 V/μm,当电场为6.4 V/μm时,电流密度可以达到0.67 mA/cm²,场增强因子为3360.稳定性测试表明,在5 h内,4.5 V/μm的电场下,其波动不超过25%.将制备的ZnO纳米棒应用到有机/无机电致发光中,其中ZnO纳米棒为电子传输层,m-MTDATA(4,4',4″-tris{N,(3-methylphenyl)-N-phenylamino}-triphenylamine) 为空穴传输层,得到了ZnO的342 nm的紫外电致发光,此发光较ZnO纳米棒光致发光的紫外发射有约40 nm的蓝移. 关键词： ZnO纳米棒 场发射 水热法 有机/无机复合电致发光     

对以并五苯和酞菁铜为不同有源层的有机薄膜晶体管特性研究

通过扫描电镜和X射线衍射对SiO₂衬底上生长并五苯和酞菁铜薄膜的表面形貌进行表征,并得到在SiO₂衬底上生长的并五苯薄膜是以岛状结构生长,其大小约为100nm,且薄膜有较好的结晶取向,呈多晶态存在. 酞菁铜薄膜则没有表现出明显的生长机理,其呈非晶态存在. 还对通过掩膜的方法制作得以酞菁铜和并五苯为有源层的顶栅极有机薄膜晶体管的特性进行了研究. 有源层的厚度为40nm,绝缘层SiO₂的厚度为250nm,器件的沟道宽长比(W/关键词： 有机薄膜晶体管 并五苯薄膜 酞菁铜薄膜 μ_EF)')" href="#">场效应迁移率(μ_EF)     

Simultaneous determination of phenylglyoxylic acid, mandelic acid, styrene glycol and hippuric acid in primary culture of rat hepatocytes incubate by high-performance liquid chromatography

A simple HPLC method for the simultaneous determination of phenylglyoxylic acid (PGA), mandelic acid (MA), styrene glycol (SG) and hippuric acid (HA) in cell culture medium was developed. Analysis was performed on a C(18) column with a mobile phase composed of methanol-potassium dihydrogen phosphate (pH 2.5; 10 mM; 10:90, v/v) at 220 nm. The flow-rate of mobile phase was set at 0.5 mL/min. The mean absolute recoveries of PGA, MA, SG and HA were 95.9, 98.4, 98.0 and 97.1%, respectively. The inter-day and intra-day precisions, determined at three concentration levels, were less than 10% of RSD. The limits of quantification for PGA, MA, SG and HA were 13.2, 13.1, 14.5 and 11.2 microM with RSD less than 20%. The limits of detection for PGA, MA, SG and HA were 4.6, 4.6, 5.1 and 3.9 microM, respectively. The method was successfully applied to study the stereoselective metabolism of SG and MA in primary culture of rat hepatocytes. The results show that there is stereoselective metabolism for both of MA and SG in primary culture of rat hepatocytes. The extent of biotransformation from S-MA to PGA is significantly greater than that from the R enantiomer and the main metabolites are PGA and HA for S-SG and R-SG, respectively.     

基于形态滤波的心电信号去除基线漂移方法

去除基线漂移是心电信号预处理过程中的重要一步,常见方法具有计算量大、结果不佳等缺陷.本文运用形态学理论,结合心电信号特征,提出了基于形态学的心电信号基线漂移去除方法.该方法采用不同形状及尺寸的结构元素设计了两级形态学滤波器,分别对信号进行开闭、闭开级联组合运算.经验证,提出的方法能很好保持心电信号的特征形态,提高了信噪比,减小了均方差,有效去除了基线漂移噪声.     

A modified LC-MS/MS method for determination of tetramethylpyrazine in microdialysis samples and calibration of home-made linear probes

Tetramethylpyrazine (TMP) is one of the most important active ingredients of a Chinese herb Ligusticum wallichii Franchat, which is widely used for the treatment of cardiovascular diseases. Several factors may affect TMP exposure after topical administration, resulting in large variability and demanding further elucidation of drug distribution. This paper describes a new efficient reliable LC‐MS/MS assay for the determination of TMP in dermal microdialysate, where TMP was separated on an Agilent C₁₈ column (3.5 µm, 100 mm × 2.1 mm i.d.) using a mixture of methanol, water and acetic acid (50:50:0.6, v/v/v) at a flow‐rate of 0.3 mL/min. The retention time was 1.89 min for TMP and 1.17 min for the internal standard (caffeine). Histological analysis confirmed an inflammatory response to the microdialysis probes and the presence of a collagen capsule. The membrane extraction efficiency (percentage delivered to the tissue space) for TMP was not altered through the implant lifetime. The validation and sample analysis results showed that the method is precise, accurate and well suited to support dermal microdialysis experiments. Copyright © 2012 John Wiley & Sons, Ltd.     

Confirmation on origin of primary electron in solid state cathodoluminescence

This paper utilizes the brightness-voltage waveform curve to investigate the primary electron in solid state cathodoluminescence. The results indicate that the primary electron is from the interface state of SiO₂/MEH-PPV (Poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]) under the lower electric field which contributes to the 580-nm emission. With increasing the electric field, the 405-nm emission is obtained, and under this condition, the origin of the primary electron is mainly from tunneling.     

共价键合多层肝素薄膜修饰涂有硅橡胶的人工血管

报道一种采用医用硅橡胶涂层作软支撑共价键合多层肝素薄膜修饰人工血管等生物医学装置使其表面具有抗凝血性能的方法. 该项技术首先在人工血管的表面上涂上医用硅橡胶作为软支撑, 再在硅橡胶涂层的表面上涂上全氟磺酸(Nafion), 为接下来的层层静电组装提供活性基团. 然后将带正电荷的二苯胺重氮树脂(PA)和带负电荷的肝素分子(Hep)通过静电吸引作用交替沉积到全氟磺酸涂层的表面上. 紫外可见吸收光谱和傅立叶红外光谱数据表明, 在紫外光照射下, 重氮树脂的重氮基团与肝素的硫酸基团之间发生光化学反应, 生成硫酸酯, 使膜内层间离子键转变成共价键, 从而使肝素多层膜的稳定性大大提高. 研究表明经层层自组装和光化学反应后肝素分子呈现良好的抗凝血性能. 人工血管肝素化表面中的肝素分子以壁面结合的方式存在, 在人工血管表面固化肝素和抗凝血酶-III (AT-III)形成的络合物显示出较好的抗凝血性. 硅橡胶涂层使肝素分子与人工血管表面有一定距离, 有利于提高抗凝血性能. 在四个双层之内, 肝素对凝血酶失活的影响随着PA/Hep双层数目增加而增加, 说明了只有最外层的肝素才对凝血酶失活有直接影响. 该方法操作工艺简单, 重复性好, 可较广泛地适用于在多种生物医用装置和多孔组织工程支架材料的表面制备稳定的抗凝血涂层, 具有良好的应用前景.     

The effect of annealing temperature and film thickness on the phase of pentacene on the p+-Si substrate

This paper investigates the morphology and crystallization properties of the two crystalline phases of pentacene grown by thermal evaporation on p^＋-Si substrates at room temperature by the methods of atomic force microscopy and x-ray diffraction. This kind of substrate induces a thin film phase and a triclinic phase which are formed directly onto p^＋-Si substrates and constitute a layer consisting of faceted grains with a step height between terraces of 15.8A（1A=0.1 nm） and 14.9A, respectively. Above the critical thickness of the thin film phase, lamellar structures are found with an increasing fraction with the increase of the film thickness. When the film thickness is fixed, the fraction of lamellar structures increases with the increase of annealing temperature. These lamellar structures are identified as the second phase with a interplanar distance of 14.9A corresponding to the pentacene triclinic phase. Furthermore, the thin film phase consisting of several micrometre sized uniformly oriented grains at an annealing temperature of less than 80℃ and a deposition rate of 0.6A/s is observed.     

PZ等添加剂对氨法脱碳影响的实验研究

本文在湿壁塔实验台上,针对2.67 mol/L氨水溶液分别混入0.1 mol/L的PZ(哌嗪)、AMP(2-氨基-2-甲基-1-丙醇)、AMPD(2-氨基-2-甲基-1,3-丙二醇)和THAM(2-氨基-2-羟甲基-1,3-丙二醇)等有机胺添加剂吸收CO_2的过程,进行了20℃下的气液传质和反应动力学实验研究。实验结果表明,混入PZ可以最有效地提高氨水的吸收速率。本文还在20℃下分别进行了2.67 mol/L氨水和0.1 mol/L PZ单独吸收CO_2的吸收速率实验,研究发现,氨水和PZ的混合溶液吸收CO_2的速率强于两者单独吸收的简单加合,二者在吸收过程中相互促进。研究还发现,氨水和PZ混合溶液吸收CO_2的相互促进率最大可达近50%。