基于SVR的多股簧机床张力控制

针对多股螺旋弹簧加工机床张力控制系统的非线性特性及存在干扰的问题,提出了基于支持向量回归(Support Vector Regression, 简称SVR)的有效抑制噪声的控制算法;即在基于SVR的逆动力学建模中采取非线性松弛因子替代线性松弛因子,抑制噪声在建模过程中的影响,提高建模精度;把系统逆模型作为前馈控制器,构成伪线性系统,PID控制器作为反馈控制,组成有效抑制噪声的复合控制算法;实验结果表明,这种改进基于SVR的复合控制方式在多股螺旋弹簧张力控制系统中具有较好的控制精度和鲁棒性。     

经济微降解读

A股最近期的这一波反弹颇不寻常—不论在频率上、持续时问上,还是它们所针对的目标上（主要是对于指数攻击性而言）,都是如此。     

判别分析法对增发股投资价值的分析及预测

本文通过增发股相关指标数据的特别处理 ,对增发股投资价值进行了判别分析 ,求得了判别函数 ,并应用于增发股的投资预测     

多股流换热器优化运行和控制研究

本文针对板翅式平行流多股流换热器,从最小能耗运行方面进行了优化研究,获得了在不同目标函数下的最优运行工况。并且,结合对流换热场协同理论,提出了多股流换热器运行和控制优化方法:当被控制的目标流体入口发生工况变动后,为了保证其出口工艺条件,调节不同的辅助流体所需的能量投入是不同的,其中有一种最佳的调节组合可以实现能量投入量最小。     

风险企业的一种激励安排

风险资本家对企业管理层的增股激励是风险投资的一种常用的激励模式 .本文建立一个增股激励模型以及参数估计的方法 ,给出最佳的增股比例     

场协同下F的多股流换热器换热性能研究

本文在建立了多股流换热器的通用数值求解程序的基础上,综合考虑了多股流换热器由于通道排列效应和旁通效应产生的温度场、速度场和温差场的相互协同作用,重点分析了不同流体组织结构对多股流换热器性能的影响.最后,从场协同的角度,本文提出了流场组织协变温差场的多股流换热器性能优化方法.     

β-发夹多肽的全新设计和构象研究

引入跨股氨基酸队的方法进行β-发夹结构的设计,序列[R1G2T3F4W5V6d-p7S8V9N10Y11F12,β2]中包含二个氨基酸对V6V9和F4Y11,并以d-p7S8作转角来稳定结构.多肽合成采用Fmoc/Bu4固相合成方法.圆二色谱研究显示,β2在202 nm呈现正峰,在217.5 nm处呈负峰,为β转角和β折叠共同贡献的叠加,是典型的β-发夹结构圆二色谱特征.红外光谱研究进一步验证了圆二色谱的结果,表明β2在溶液中主要以β-发夹结构存在.     

异氰酸苯酯诱导的类胶原多肽自组装

Synthetic matrices provide powerful tools for dissecting molecular interactions involved in the organization of the extracellular matrix (ECM), establishment of cell axis polarity, and suppression of neoplasticity in pre-cancerous endothelial cells. Collagen is the most abundant protein in extracellular matrix. A de novo approach is essential for the synthesis of collagen matrices which can have a broad impact on the understanding of matrix biology and our capacity to construct safe and medically useful biomaterials. Conventionally, the ECM has been studied by an analytical "top-down" approach, where the individual components of the matrix are first isolated and then characterized to explore their biochemical and functional properties. Since native collagen is difficult to modify and can engender pathogenic and immunological side effects, its application on tissue regeneration is limited. Therefore, we attempted to synthesize artificial collagen directly through small organic molecule recognition. The collagen-like peptides possess various benefits such as being clean, programmable, and easy to modify; therefore, in recent years, they have been used as ideal substrates for the synthesis of collagen nanomaterials. The self-assembly of collagen-like peptides is mainly driven by various non-covalent interactions such as electrostatic attraction, π-π stacking, and metal coordination. This renders a difficulty in the rational design of uniform nanostructures from short synthesized peptides and demands a novel strategy. To date, small organic molecules have been rarely used for the self-assembly of collagen-like peptides. In the present study, we attempted to use the small organic molecules for the combined supramolecular self-assembly of collagen-like peptides. Initially, the collagen-like peptides, (POG)₆ and (POG)₈, synthesized by the solid-phase synthesis technique, were both modified chemically using 4, 4'-methylene bis(phenyl isocyanate) to obtain the collagen-like hybrid peptides, AP₆ and AP₈, respectively. Phenyl isocyanate contributes to the formation of potential weak forces, such as hydrogen bonds and π-π stacking at the N-terminal regions of the collagen-like hybrid peptides. The purity and molecular weight of the collagen-like hybrid peptides were analyzed using analytical high-performance liquid chromatography (HPLC) and matrix-assisted laser desorption ionization time of flight (MALDI-TOF), respectively. The stability of AP₆ and AP₈ triple helices was analyzed by circular dichroism (CD) spectroscopy. The small organic molecule 4, 4'-methylene bis(phenyl isocyanate) promoted the unfolding of (POG)₆ and increased the melting temperature (T_m) of (POG)₈ from 37.7 to 58.8 ℃to form a triple helix. The hydrodynamic radii of collagen-like hybrid peptides were measured by dynamic light scattering (DLS). Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to analyze the morphology of the aggregation states. AFM results showed that the collagen-like hybrid peptides, AP₆ and AP₈, formed nanofibers spontaneously. Consistent with the AFM results, TEM showed that the AP₆ and AP₈ collagen-like hybrid peptides also formed nanofiber structures. The formation of stable complexes was attributed to the presence of multiple weak interactions such as hydrogen bonding, π-π stacking, and hydrophobic interactions. In the present study, we demonstrated that the chemical modification of collagen-like polypeptides at the N-terminus via the small organic molecule, 4, 4'-methylene bis(phenyl isocyanate), promoted the intramolecular and intermolecular assembly of collagen-like peptides. A simple and effective strategy has been developed in this study to promote the self-assembly of collagen-like peptides.     

基于虚拟分配混合的(?)分析方法

在工业生产和日常生活中的换热网络大多属于多股流换热,为了将煨分析拓展到该类型换热过程的优化分析中,本文提出了基于虚拟分配和混合的(火积)耗散热阻定义与方法,将多股流换热网络等效为两股流换热网络。对两类典型的三股流换热网络进行分析表明,利用虚拟分配混合计算得到的(火积)耗散热阻与换热量一一对应,最小热阻原理成立。     

高效液相色谱-电喷雾质谱联用分析亚硝基脲导致的DNA股间交联

为了探讨亚硝基脲类抗癌药物对DNA的股间交联作用,以合成的1-[N-(2′-脱氧胞基)]-2-[N-(2′-脱氧鸟基)]乙烷(dG-dC)为标准品,使用高效液相色谱-电喷雾串联质谱(HPLC-ESI-MS/MS)方法测定了小牛胸腺DNA中1,3-双(2-氯乙基)-1-亚硝基脲(BCNU)导致的DNA股间交联物。DNA样品经过变性、酶解和离心过滤后,以乙酸铵溶液和乙腈为流动相,经C18反向色谱柱分离。样品经电喷雾离子源(ESI)正离子化后,采用质谱一级和二级全扫描进行定性分析;采用选择反应扫描(SRM)方式,以m/z521→289作为检测的离子碎片,测定DNA样品中dG-dC的含量。本研究为DNA股间交联的定性和定量分析提供了有效的方法。