基于虚拟响应信号的结构参数时域辨识研究

在充分考虑线性动力系统的时域响应特性以及小波包分析的频率空间剖分特性的基础上,提出了一种基于虚拟响应信息提取的信号去噪新方法.虚拟响应虽然没有在结构动力检测过程中真实发生,但却是在某种激励下可以实现的一个响应,因此,根据虚拟响应信息同样可以进行结构系统的动力识别.数值研究表明,对于地脉动响应这种有效信号频带与噪声频带相互覆盖的低信噪比信号而言,小波阈值去噪法已无能为力,而基于虚拟响应信息提取的信号去噪方法则有较好的去噪效果.     

应用可视芯片技术高通量鉴别8种鱼成分

为探索鱼肉品种快速鉴别方法,以鱼类小清蛋白基因为靶标,设计了多宝鱼、银鲳鱼、金枪鱼、暗纹东方鲀、青石斑鱼、带鱼、大黄鱼以及东星斑鱼8种鱼的通用引物以及特异性探针,利用可视芯片技术,建立了一种鱼肉品种的高通量快速检测方法。该方法特异性好、灵敏、通量高,可同时准确鉴别8种鱼成分,检测灵敏度均可达0.1ng/μL,且结果肉眼可见。该方法在鱼肉及其制品掺假现场快速筛查方面具有较大应用潜力。     

飞行器气动参数辨识进展

飞行器气动参数辨识研究的主题,是应用系统辨识技术从飞行试验数据求取气动力,从而建立飞行器动力学系统的数学模型.它研究的对象是飞行器;解决的是空气动力学问题;采用的基本方程是飞行动力学的运动方程组;应用的研究手段是现代控制论的滤波、预测和估计理论.它是处于空气动力学、飞行力学、弹性力学和现代控制论之间的应用性研究课题. 本文综述了国内外公开发表的飞行器参数辨识研究的理论结果和实践经验,分八个专题——模型辨识,参数估计,数据预处理和相容性检验,试验设计与最佳输入,弹性与非定常效应,频域辨识,闭环辨识,辨识准度与系统验证——评述其研究进展和现状.     

绕旋转圆柱流动涡尾流结构和临界状态特性

采用作者提出的基于区域分解、有限差分法与涡法杂交的数值方法,结合高阶隐式差分格式,和以修正的不完全ＬＵ分解为预处理器的共轭梯度法作求解器．系统地研究了雷诺数Ｒｅ＝１０００,旋转速度比ａ∈（０．５,３．２５）范围内,绕旋转圆柱从突然起动到充分发展,长时间内尾流旋涡结构和阻力、升力系数的变化规律．计算所得流动图案与实验流场显示符合很好．数值试验证实了临界状态的存在,并首次给出了临界状态时的旋涡结构特性,指出最佳升阻比也在该状态附近得到     

Photolysis of 2-dialkylamino-3-amino(or alkylamino)-1,4-naphthoquinones

Using¹H and¹³C NMR spectroscopy, naphthodihydroimidazolediols were identified as the primary products of photolysis of 2-dialkylamino-3-amino(alkylamino)-1,4-naphthoquinones. Their further non-photochemical (thermal) transformations depend on their structure and on the photolysis conditions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 358–362, February, 1993.     

In vitro antiproliferative activity of glabridin derivatives and their in silico target identification

Abstract

Novel Mannich base derivatives of glabridin were synthesized and their antiproliferative activity were performed along with our previously reported glabridin-chalcone hybrids molecules (GCHMs) against various human cell lines MDA-MB-231 (breast adenocarcinoma), HEK-293 (embryonic kidney cell line), K562 (leukemia), MCF-7 (breast adenocarcinoma), HeLa (cervix adenocarcinoma), HepG2 (hepatocellular carcinoma) and WRL-68 (hepatic carcinoma). The result showed that the glabridin significantly reduced cell proliferation with IC₅₀ ranges from 3.67 to 58.30?µM against all the tested cell lines. The remarkable reduction in antiproliferative activity 2’,4’-dimethoxyglabridin and GCHMs compounds with phenolic OH groups protected by methoxy (OCH₃) groups suggested that the free OH groups are essential factor for the antiproliferative activity of glabridin and its derivatives. The Mannich base derivatives of glabridin showed moderate activity IC₅₀ (2.20–>95.78?µM). Furthermore, in silico target identification analysis revealed that AKT1, DECR1 and NOS1 are the potential targets for glabridin and their derivatives.     

Structure-activity relationship of Ca2+ channel blockers: A study using conformational analysis and chemometric methods

Summary A structure-activity relationship study has been done on 8 compounds with the activity known as Ca²⁺ channel blockers. Conformational analysis was carried out using a molecular mechanics method. The 3D-QSAR approach was used and the most polar functional groups present in all the molecules were considered. Eight interatomic distances are necessary to define the relative spatial disposition of these relevant molecular fragments. The structure-activity relationship between interatomic distances and biological activity was performed using statistic and chemometric methods. In particular, with Principal Component Analysis, it was possible to reduce the number of interatomic distances: only six of the eight distances are sufficient to describe the system in a useful way. A classification method was iteratively used to select the most probable conformations linked to the biological activity and to build a model able to classify conformations according to their biological behaviour. Cluster analysis on the active selected conformations subsequently allowed the identification of two different geometrical patterns for the active compounds. Finally the validity of the model was verified by correctly predicting the activity of other molecules not used in the construction of the model but possessing known activity.     

Individual determination of ortho and non-ortho substituted polychlorobiphenyls (PCBs) in sediments by high performance liquid chromatographic pre-separation and gas chromatography/ECD detection

Summary An analytical procedure for the individual determination of ortho and non-ortho PCB congeners in sediments, using high performance liquid chromatography (HPLC) preseparation and gas chromatography/ECD detection, is described. Gas chromatography/FTIR spectrometry (GC/FTIR) and gas chromatography/mass spectrometry (GC/MS) were employed for individual congener identification and determination. Sample extraction, clean-up of extract and selective elution procedures were optimized by using reference certified marine sediment samples. Recovery and precision were typically 83% and 16% respectively at 2 ng/g of total PCB content. The proposed procedure, tested by analyzing real sediment samples, showed a reproducibility better than 20% at 13 ng/g PCB level.     

食用香料甲基2-甲基-3-呋喃基二硫醚的分离提纯及结构鉴定

 用气相色谱法分离提纯食用香料甲基 2 甲基 3 呋喃基二硫醚 ,纯度 (质量分数 )达到 99.5%。分离柱为4%FFAP +1 %H3PO4ChromosorbW /AW DMCS(80目～ 1 0 0目 )不锈钢柱。用红外光谱、气相色谱 /质谱和核磁共振谱进行了结构鉴定。