利用遗传算法优化透明质酸发酵培养基

运用遗传算法对透明质酸(HA)产生菌--马链球菌兽瘟亚种ATCC 39920发酵培养基的6种组份进行了优化研究.每个长度为36位的染色体编码一种培养基配方,以HA产量为适应度函数值对其进行评价.经过4代的进化,各参数的取值范围收敛于最优区域.最终以40个实验样本完成了6种培养基成分、64个浓度水平的优化选择.优化后的培养基的构成为:葡萄糖44.0g/L,酵母膏5.2g/L,蛋白胨8.4g/L,牛肉膏9.8g/L,KH2PO41.45g/L,MgSO42.8g/L.采用优化培养基的HA产量达0.395g/L,较原培养基提高了31.2%,生产成本也大幅度降低.     

一种国产新型反应性增容剂在PA6与ABS合金中的应用

以国产苯乙烯-丙烯腈-顺丁烯二酸酐共聚物(SAM)为原位反应性增容剂,制备了超韧PA6/ABS合金.在m(PA6)/m(ABS)为50/50～70/30和SAM加入量为3%～4%时,23 ℃的合金悬臂梁缺口冲击强度达900 J/m以上;-18 ℃的合金悬臂梁缺口冲击强度达270 J/m.电镜和力学性能测试表明原位反应性增容使PA6和ABS两相界面张力降低,并使ABS分散颗粒变小及更均匀地分散于PA6中.另外,过多的SAM用量将导致PA6与SAM间的深度反应,使体系粘度上升和ABS相难于被分散.总之,SAM用量、相界面张力和ABS分散颗粒大小是影响该合金力学性能的关键因素.     

束带状WO3的水热法制备及其吸附性能

采用D/L型甲硫氨酸作为添加剂,使用一步水热法制备了微米级束带状六方相WO 3,考察了甲硫氨酸添加量对WO 3晶体结构、微观形貌和吸附性能的影响.研究结果表明,D/L型甲硫氨酸对六方相WO3起结构导向剂的作用.当甲硫氨酸添加量为0.05 g时,WO3纳米棒沿[001]方向定向生长,并相互附着形成均一的微米级束带状形貌.在吸附测试中,WO 3样品对亚甲基蓝表现出优秀的吸附性能,25 mg样品在3 min内对亚甲基蓝(20 mg/L)的吸附量为37.1 mg/g,在废水处理等领域中有广阔的应用前景.     

广东经济社会核算矩阵研究

在探讨建立区域经济社会核算矩阵可行性的基础上,构造了广东经济社会核算矩阵(G—SAM),并利用现有的统计数据编制了1998年度G—SAM。G—SAM为基于可持续发展的广东经济可计算一般均衡模型提供基础数据支持。     

一种增强的谱幅值调制方法及其在复杂干扰下滚动轴承故障诊断中的应用

谱幅值调制（Spectral Amplitude Modulation,SAM）作为一个经验的和自动的非线性滤波方法,可以有效地识别滚动轴承故障信息。然而,当滚动轴承故障信号中含有复杂干扰成分时,SAM 中的故障特征频率会变得模糊,甚至难以识别。针对上述问题,提出了一种增强谱幅值调制方法（Enhanced Spectral Amplitude Modulation,eSAM）,通过修正信号平方包络的无偏自相关代替修正信号的平方包络来生成 SAM。通过自相关处理,进一步降低由于非线性滤波过程产生的不相关随机噪声干扰,从而提高了 SAM 方法的稳定性。通过一组仿真信号、一组齿轮箱轴承实验信号和不同运行工况下的高速列车轴箱轴承实验信号进行了验证,结果表明该方法可以有效降低复杂干扰的影响,提取出的故障特征更加明显,通过与 SAM 方法和传统峭度图方法对比,证明了该方法的优越性。     

甲硫氨酸铈的合成及其对橡胶硫化性能的研究

使用复分解法,用甲硫氨酸和氯化铈合成了甲硫氨酸铈。经过元素分析、ICP-OES分析、傅里叶红外光谱分析和热重表征,确定配合物的分子式为CeCl_3(C_5H_(10)NO_2S)_3·2H_2O,研究了其对天然橡胶的硫化促进作用。甲硫氨酸铈作为硫化促进剂加入天然橡胶中相比于空白胶料,模量、焦烧时间得到延长;溶胀指数由5.5872下降至5.1395,交联密度由8.11×10~(-5) mol/cm~3提升至9.90×10~(-5) mol/cm~3;对添加甲硫氨酸铈的胶料进行硫化动力学拟合,得到各阶段的硫化反应速率常数k,进而求得硫化反应活化能为E_1=73.85 kJ/mol;E_2=91.05 kJ/mol;E_3=127.00 kJ/mol。相对于空白胶料,硫化反应活化能降低,甲硫氨酸铈具有硫化促进作用。     

淀粉酶产色链霉菌1628发酵培养基及发酵条件的优化

淀粉酶产色链霉菌1628(Streptomyces diastatochromogenes)是一株具有广阔应用前景的生防菌株,其合成的主要活性物质为核苷类抗生素——丰加霉素.为了提高淀粉酶产色链霉菌的发酵水平,本研究采用单因素和正交实验设计,对菌株1628的发酵培养基和发酵条件进行了优化,优化后的最佳培养基配方为:可溶性淀粉1.5%、黄豆粉5%、FeSO40.1%、CaCO30.5%、NH4NO3 0.3%、KH2PO4 0.3%,最适初始pH7.0.在供试的发酵条件内,装液量60mL/250mL,发酵温度28℃,摇床转速180r/min,发酵时间为92h.活性物质丰加霉素的产量最高156.17mg·L-1,比优化前提高了3.3倍.     

碳纤维碳化特征的SAM微观分析

本文应用SAM方法检测了由不同工艺条件造成的碳纤维的污染和产生的缺陷。对任意一根碳纤维,其表面和内部的碳俄歇峰、峰高和峰形都有差异,这一差异导致碳沿径向分布不均匀,并影响到碳纤维的力学性能。采用SAM的方法可监测予氧化和碳化过程中的工艺参数以便提高碳纤维的质量。      

马来酸酐共聚方式对PA6/ABS共混物性能的影响

分别制备了马来酸酐与苯乙烯-丙烯腈无规共聚物(SAM)增容的尼龙6(PA6)/ABS/SAM共混物、马来酸酐接枝共聚的丙烯腈-丁二烯-苯乙烯共聚物(ABS-g-MA)增容增韧的PA6/ABS-g-MA共混物。结果表明,两个体系中ABS都可以均匀分散;冲击测试发现样条厚度为6.35 mm时,PA6/ABS-g-MA共混物出现明显的脆韧转变,PA6/ABS/SAM共混物为脆性断裂;样条厚度为3.18 mm时,两个体系都有明显脆韧转变;Vu-Khanh方程表明,PA6/ABS-g-MA共混物具有更高的裂纹扩展能(Gi)和撕裂模量(Ta),性能更好。     

微图案BiFeO_3薄膜的光刻自组装制备与表征(英文)

利用光刻自组装技术在玻璃基板上成功制备出图案化的BiFeO3薄膜.AFM和接触角测试表明,紫外光照射引起十八烷基三氯硅烷(OTS)单层膜改性,形成憎水的自组装单分子(SAM)区域和亲水的硅烷醇区域;XRD和XPS结果显示,OTS单层膜和紫外照射处理的玻璃基板表面诱导吸附的薄膜为纯相六方扭曲钙钛矿结构的BiFeO3薄膜;SEM和EDS表明,SAM区域沉积的BiFeO3薄膜不连续,在超声波震荡下容易脱落,而硅烷醇区域沉积的BiFeO3薄膜致密均一,与基底结合牢固,边缘轮廓清晰.     

Molecular dynamic simulation and characterization of self-assembled monolayer under sliding friction

The frictional mechanisms of a self-assembled monolayer (SAM) during nano-scale sliding are studied using molecular dynamics (MD) simulation. The MD model consists of a gold slider and gold substrate with n-hexadecanethiol SAM chemisorbed to the substrate. The trajectory, tilt angles, normal forces, frictional forces, friction coefficients and potential energies per molecular chain of the SAM molecules are evaluated during the frictional process for various parameters including as sliding height, sliding direction (i.e. pro- or anti- the SAM tilt angle), sliding velocity and system temperature. The various parameters are discussed with regard to frictional forces, mechanisms and SAM structural transition. Results show that stick-slip occurs and is related to the sliding period and tilt angle of the SAM molecules. Amplitude of the stick-slip cycle increases with decreasing sliding height until reaching a critical sliding height, which is characterized such that sliding below the critical height causes irreversible changes in the SAM molecular organization and cumulative loss of SAM lubricating efficiency. Different SAM recovery mechanisms were found for different sliding directions relative to SAM tilt angle (pro- or anti-tilt). In both cases, minimum friction occurred during the SAM tilt-angle recovery phase. The friction force curves for these two cases also showed a regular phase shift above the critical height. For stick-slip sliding above the critical height, anti-tilt sliding had significantly lower average friction, but this trend inverted below the critical height. Sliding lower than the critical height cause progressive disorder of the SAM structure and the characteristic differences between pro- and anti-tilt sliding were progressively lost.     

高性能陶瓷材料的俄歇能谱分析

降低陶瓷材料表面电荷的积累一直是俄歇分析技术能否成功应用于该类材料必须解决的首要问题. 通过实验认为：陶瓷材料试样减薄法可以用来降低表面电荷.采用这种方法,样品可分析区域大小仅依赖于电子束斑尺寸. 因而,用Microlab 310--F热场发射扫描俄歇微探针分析仪能在几十纳米的微区内,获取结构信息和除氢氦外的化学成分信息,突破了陶瓷材料在低电压、低电流下约几十微米的分析范围. 在此基础上,挑选了掺Dy的α-Sialon ,掺Y、La的α-Si₃N₄与以Al₂O₃为基体加入SiC晶须, 并通氮气氛处理的三种高性能陶瓷作为实验对象,分析和研究它们的晶粒、界面的成份、化学态和结构.发现α-Si₃N₄和α-Sialon陶瓷中的Si(LVV, KLL)峰位都会向低能端漂移,峰位分别为: 84eV 和1613eV. Si--N--O的结合态又使Si(LVV)峰继续漂移到80eV左右. 掺Y、La的α-Si₃N₄的玻璃相区, Si至少以两种或者两种以上的化学态存在.掺Dy的α-Sialon陶瓷的局部区域内有四种组分不同的固溶相及三种组分不同的晶间相. 另外, 在SiC与SiC-BN-C纤维补强复合陶瓷材料的断裂面,观察到从SiC基体拔出的纤维表面的大部分是残留的C层与C-BN交界层.     

声学显微镜用于碳纤维复合材料钻孔分层检测的研究

本文利用声学显微镜对多向碳纤维复合材料钻孔后不同深度的分层进行了检测研究。根据检测试验结果及分析, 总结出了立体分层模型, 并对分层形成机理进行了探讨。     

Use of ultra-thin organic silane films for the improvement of gold adhesion to the silicon dioxide wafers for (bio)sensor applications

A mono-functional silane reagent, 3-mercaptopropyltrimethoxysilane (MPS) was used to modify the surface of silicon wafers. The structure of the SAMs formed with the MPS was investigated by contact angle measurements, ellipsometry, AFM, and X-ray photoelectron spectroscopy (XPS). The deposition of a metallic gold layer via ultra-high vacuum (UHV) evaporation reveals good adhesion properties on Au/MPS/SiO₂/Si structure. The “chemisorption” between the SAM and the gold evaporated layer is confirmed by adhesion tests and optimum curing treatment is found 1 h at 100 °C). This very simple methodology, avoiding the usage of Cr and other metals as undercoating layers and could be proposed further for (bio)sensors applications.     

Preparation and tribological characteristics of sulfonated self-assembled monolayer of 3-mercaptopropyl trimethoxysilane TiO2 films

Silane coupling reagent (3-mercaptopropyl trimethoxysilane (MPTS)) was prepared on silicon substrate to form two-dimensional self-assembled monolayer (SAM) and the terminal–SH group in the film was in situ oxidised to–SO₃H group to endow the film with good chemisorption ability. Thus, TiO₂ thin films were deposited on the oxidised MPTS-SAM to form composite thin films, making use of the chemisorption ability of the–SO₃H group. Atomic force microscope (AFM), and contact angle measurements were used to characterise TiO₂ films. Adhesive force and friction force of TiO₂ thin films and silicon substrate were measured under various applied normal loads and scanning speed of AFM tip. Results showed that the friction force increased with applied normal loads and scanning speed of AFM tip. In order to study the effect of capillary force, tests were performed in various relative humidity (RH). Results showed that the adhesive force of silicon substrate increases with RH and the adhesive force of TiO₂ thin films only increases slightly with RH. Research showed that surfaces with more hydrophobic property revealed the lower adhesive and friction forces.     

不同沉积工艺下Au/P-CdZnTe接触界面的研究

采用超声波扫描(SAM)、俄歇电子能谱分析技术(AES)、电极粘附力测试和I-V特性测试等方法研究了化学沉积、溅射和真空蒸发三种不同沉积工艺条件下Au/p-CdZnTe接触界面的各种特性.通过实验结果可以看出,化学法沉积的Au电极能形成较好的欧姆接触特性,但其操作工艺不容易控制,电极接触层均匀性较差,在器件使用过程中,容易引起电极的退化;溅射沉积的Au电极有着较好的附着力,但对CdZnTe表面的损伤较大,欧姆接触特性较差;真空蒸发法沉积的Au电极,有着较好的欧姆接触特性,且其电极接触层也较为均匀,只是电极附着力相对较小,但可以通过合适的退火工艺进行改善.     

微孔聚合物皮层厚度测量的扫描声显微方法

微孔发泡是一种有广泛应用前景的聚合物改性方法。皮层的存在对微孔结构材料的性能有很大的影响,皮层厚度的测量、工艺控制和理论计算是微孔材料加工中的主要问题。文章介绍了一种测量微孔聚合物皮层厚度的新的有效方法——扫描声显微(SAM)方法,并测量了微孔聚苯乙烯和微孔聚碳酸酯的皮层厚度。     

Modified method time measurements for ergonomic planning of production systems in the manufacturing industry

The paper reports on an evaluation of a method called ErgoSAM. This method is based on SAM, a higher-level method-time-measurement (MTM) system, and is for use by production planners, e.g. production engineers. In addition to the SAM information, the ErgoSAM method considers information on weight handled or forces applied and work zone. The method is designed to predict the physical demands of work postures, force and repetitivity, according to a scientific model, the Cube model. In co-operation with the Volvo Car Corporation, six work-stations of an assembly line were analysed by a production engineer using ErgoSAM. The total assembly time analysed was about 17 minutes. The results were compared to results from ergonomic analyses made by an ergonomist using the Volvo Car Corporation's standards. The results showed that ErgoSAM predicts work situations of high physical stress for the workers. However, the method does not consider stressful positions for the hand, wrist and neck or mental stress. The production engineer judged the ErgoSAM analyses to require about 5% more time than SAM analyses alone. It is concluded that the method shows considerable promise for predicting physically stressful work situations, but needs to be further evaluated and refined.     

辅以波谱分析的高分辨率影像面向对象分类研究

随着遥感影像空间分辨率的提高,地物的空间信息更加丰富,地物尺寸、形状以及相邻地物的关系得到更好的反映,因此目前高分辨率影像分类方法更侧重于利用地物的空间信息,分类过程中参与较多的人为主观因素,在地物类型未知的地区很难进行解译工作。另外,分割过于细碎导致操作数据量太大也是高分辨率影像分类的难题之一。论文提出了辅以波普分析的高分辨率影像面向对象分类方法,即在传统面向对象分类方法的基础上结合影像波谱分析,先对影像光谱角制图粗分类、掩膜操作,再面向对象精分类,较好解决了以往面向对象分类方法地物类型的不确定性和分割细碎等问题。试验以空间分辨率为0.5米的八波段WorldView2影像为研究数据提取西部那曲地区道路和河流,精度达到96.36%。