Analysis of Optimization for Preliminary Design of Multi-Component Mooring Systems

Multi-component mooring systems become widely used in deep water position-keeping of drilling and production platforms. However, versatile materials make it difficult to design appropriate mooring lines made of several segments. Based on catenary equations of a multi-component mooring line at a specific water depth, this paper establishes a minimum model for designing this kind of lines. The model is solved by Genetic Algorithm and Multi-Objective Planning respectively. The model is verified by its application to a practical mooring design assignment—a quasi-static analysis for a large semi-submersible. The optimal result is finally obtained with the aid of design graphs.

Dynamic probabilistic design technique for multi-component system with multi-failure modes

For unacceptable computational efficiency and accuracy on the probabilistic analysis of multi-component system with multi-failure modes,this paper proposed multi-extremum response surface method(MERSM).MERSM model was established based on quadratic polynomial function by taking extremum response surface model as the sub-model of multi-response surface method.The dynamic probabilistic analysis of an aeroengine turbine blisk with two components,and their reliability of deformation and stress failures was obtained,based on thermal-structural coupling technique,by considering the nonlinearity of material parameters and the transients of gas flow,gas temperature and rotational speed.The results show that the comprehensive reliability of structure is 0.9904 when the allowable deformations and stresses of blade and disk are 4.78×10–3 m and 1.41×109 Pa,and 1.64×10–3 m and 1.04×109 Pa,respectively.Besides,gas temperature and rotating speed severely influence the comprehensive reliability of system.Through the comparison of methods,it is shown that the MERSM holds higher computational precision and speed in the probabilistic analysis of turbine blisk,and MERSM computational precision satisfies the requirement of engineering design.The efforts of this study address the difficulties on transients and multiple models coupling for the dynamic probabilistic analysis of multi-component system with multi-failure modes.

Peak earthquake response of structures under multi-component excitations

Accurate estimation of the peak seismic responses of structures is important in earthquake resistant design. The internal force distributions and the seismic responses of structures are quite complex, since ground motions are multidirectional. One key issue is the uncertainty of the incident angle between the directions of ground motion and the reference axes of the structure. Different assumed seismic incidences can result in different peak values within the scope of design spectrum analysis for a given structure and earthquake ground motion record combination. Using time history analysis to determine the maximum structural responses excited by a given earthquake record requires repetitive calculations to determine the critical incident angle. This paper presents a transformation approach for relatively accurate and rapid determination of the maximum peak responses of a linear structure subjected to three-dimensional excitations within all possible seismic incident angles. The responses can be deformations, internal forces, strains and so on. An irregular building structure model is established using SAP2000 program. Several typical earthquake records and an artificial white noise are applied to the structure model to illustrate the variation of the maximum structural responses for different incident angles. Numerical results show that for many structural parameters, the variation can be greater than 100%. This method can be directly applied to time history analysis of structures using existing computer software to determine the peak responses without carrying out the analyses for all possible incident angles. It can also be used to verify and/or modify aseismic designs by using response spectrum analysis.

Reliability analysis for aeroengine turbine disc fatigue life with multiple random variables based on distributed collaborative response surface method

The fatigue life of aeroengine turbine disc presents great dispersion due to the randomness of the basic variables,such as applied load,working temperature,geometrical dimensions and material properties.In order to ameliorate reliability analysis efficiency without loss of reliability,the distributed collaborative response surface method(DCRSM) was proposed,and its basic theories were established in this work.Considering the failure dependency among the failure modes,the distributed response surface was constructed to establish the relationship between the failure mode and the relevant random variables.Then,the failure modes were considered as the random variables of system response to obtain the distributed collaborative response surface model based on structure failure criterion.Finally,the given turbine disc structure was employed to illustrate the feasibility and validity of the presented method.Through the comparison of DCRSM,Monte Carlo method(MCM) and the traditional response surface method(RSM),the results show that the computational precision for DCRSM is more consistent with MCM than RSM,while DCRSM needs far less computing time than MCM and RSM under the same simulation conditions.Thus,DCRSM is demonstrated to be a feasible and valid approach for improving the computational efficiency of reliability analysis for aeroengine turbine disc fatigue life with multiple random variables,and has great potential value for the complicated mechanical structure with multi-component and multi-failure mode.

Simultaneous determination of five phenylethanoid glycosides in Cistanches Herba using quantitative analysis of multi-components by single marker

In the present study, a method for the quantitative analysis of multi-components by single marker(QAMS) has been developed and validated for the simultaneous determination of echinacoside(ECH), tubuloside A, acteoside, isoacteoside, and2’-acetylacteoside in Cistanches Herba. ECH was used as the internal standard(IS) to obtain the relative correction factors(RCFs) of the other four phenylethanoid glycosides(PhGs);meanwhile, various influencing factors on RCFs were investigated under different conditions. The content of each component was calculated with RCF. The results were compared with those obtained by the external standard method(ESM) to verify the feasibility and accuracy of the established QAMS method. No significant difference was found in the quantitative results of 10 batches of Cistanches Herba between QAMS and ESM. The proposed QAMS method for simultaneous determination of PhGs in Cistanches Herba is accurate and feasible, providing an efficient and economical approach for the quality control of Cistanches Herba.

Vector semi-rational rogon-solitons and asymptotic analysis for any multi-component Hirota equations with mixed backgrounds

The Hirota equation can be used to describe the wave propagation of an ultrashort optical field.In this paper,the multi-component Hirota(alias n-Hirota,i.e.n-component third-order nonlinear Schrodinger)equations with mixed non-zero and zero boundary conditions are explored.We employ the multiple roots of the characteristic polynomial related to the Lax pair and modified Darboux transform to find vector semi-rational rogon-soliton solutions(i.e.nonlinear combinations of rogon and soliton solutions).The semi-rational rogon-soliton features can be modulated by the polynomial degree.For the larger solution parameters,the first m(m<n)components with non-zero backgrounds can be decomposed into rational rogons and grey-like solitons,and the last n-m components with zero backgrounds can approach bright-like solitons.Moreover,we analyze the accelerations and curvatures of the quasi-characteristic curves,as well as the variations of accelerations with the distances to judge the interaction intensities between rogons and grey-like solitons.We also find the semi-rational rogon-soliton solutions with ultrahigh amplitudes.In particular,we can also deduce vector semi-rational solitons of the ncomponent complex mKdV equation.These results will be useful to further study the related nonlinear wave phenomena of multi-component physical models with mixed background,and even design the related physical experiments.

Enantiodifferentiation of chiral diols and diphenols via recognition-enabled chromatographic^(19)F NMR

A novel and efficient method for distinguishing between chiral diols and diphenols has been established through the use of^(19)F NMR spectroscopy.Central to this system's efficacy is a chiral amine,strategically modified with a CF_(3)group.This amine reacts in-situ with 2-formylphenylboronic acid to create a chiral^(19)F-labeled probe.This probe demonstrates discriminatory capabilities by interacting with hydroxy-containing analytes to form boronic esters.These esters produce distinct^(19)F NMR signals that vary according to their stereoconfiguration,facilitating accurate chiral differentiation.The method's resolution capacity was demonstrated by successfully identifying 12 distinct chiral analytes(six pairs of enantiomers)in complex mixtures,highlighting its extensive potential in diverse chiral analysis applications.

Instantaneous polarization filtering focused on suppression of surface waves

The different characteristics of polarization of body and Rayleigh waves make it possible to separate these two types of waves by their characteristics and suppress the latter.The moving time-window analysis often is used in polarization filtering but it is difficult to determine a suitable time-window length,resulting in some problems,such as complex eigenvalues and non-convergence.For overcoming these disadvantages,in this paper,we introduce the concept of complex-trace analysis and conduct de-noise processing to suppress undesirable surface waves by instantaneous polarization analysis in the case of horizontal and vertical component seismic recordings from the Hauinan coal mine.The performance of the method is illustrated by examples with synthetic and field data and its effectiveness to remove surface waves from multi-component seismic data is demonstrated.

基于构件的钢筋混凝土核心筒结构地震损伤分析

为了研究地震作用下钢筋混凝土核心筒结构的损伤,基于低周反复荷载作用下钢筋混凝土剪力墙及连梁的损伤模型,通过加权系数法合理地考虑局部损伤向整体损伤迁移转化的多尺度效应,建立了能够反映构件损伤、楼层损伤以及整体结构损伤三者之间迁移演化规律的钢筋混凝土核心筒地震损伤模型。结合试验结果,对损伤模型的有效性进行了验证,并给出了钢筋混凝土核心筒的损伤状态及相应的损伤指数范围。结果表明,该损伤模型能够较好地描述钢筋混凝土核心筒结构的地震损伤发展过程与程度,研究结果可为该类结构的地震损伤评估以及基于损伤的抗震设计方法的建立提供理论依据。

一测多评技术在鼻咽解毒胶囊质量评价中的应用

目的建立鼻咽解毒胶囊一测多评的含量测定方法 ,验证该方法在鼻咽解毒胶囊质量控制中应用的可行性和准确性。方法以盐酸小檗碱为内参物,建立盐酸小檗碱与黄芩苷的相对校正因子,同时根据盐酸小檗碱与巴马汀、黄连碱、表小檗碱的内在函数关系,应用于含量测定,建立其一测多评法的多指标质量控制方法。结果建立了鼻咽解毒胶囊中多种成分一测多评法方法学的考察模式。结论以盐酸小檗碱、巴马汀、黄连碱、表小檗碱和黄芩苷为指标,采用一测多评法控制鼻咽解毒胶囊质量可行。

高墩大跨连续刚构桥梁的地震经济风险分析

在基于性能的地震工程风险评估框架基础上,针对某高墩大跨连续刚构桥,选用一组地震记录,利用增量动力分析(IDA)方法,借助桥墩损伤状态研究成果,建立解析损伤脆弱性函数,通过假定损失比,将桥梁结构的地震经济风险表达为年预期损失(EAL)形式.实例分析结果表明:在设定地震下,由于中小级别地震所造成的年预期损失约占总损失的72%.对于地震多发地区,高墩大跨连续刚构桥的地震经济风险主要来自于中小地震的危险性,决策者应采取适当措施减小地震经济风险.

基于改进IMK恢复力模型的填充墙RC框架结构地震易损性分析

为了对填充墙RC框架结构在设防大震下的抗震能力进行评估,采用OpenSees有限元软件,建立了填充墙RC框架结构的数值模型,其中,梁柱构件采用基于改进IMK恢复力模型的集中塑性铰单元进行建模,填充墙用双对角斜撑受压杆模拟,并采用基于Clough模型的桁架单元建模。以填充墙的不同布置方式作为参数,设计了4种模型,对模型进行了44条地震波下的增量动力时程分析和倒塌易损性分析。结果表明,底层不布置填充墙的模型和底部两层各有一跨布置填充墙的模型不满足我国规范中"大震不倒"的性能要求,在实际工程中应尽量避免运用此类型的框架结构,需要对已有的此类结构进行加固处理。

Characterization and mapping of the multi-component release kinetics of a Traditional Chinese Medicine dosage form using a modified LC/MS/MS method and chemomic release kinetic theory

It is essential to develop effective methods for the quality control of the traditional medicine with multiple components.However,few researches on the quality control have been conducted to interpret the holistic characteristics of the traditional medicine in terms of dissolution/release.In this study,the multi-component release kinetics of Traditional Chinese Medicine(TCM)dosage forms was characterized and mapped by multivariate analysis techniques in the field of‘‘-omics’’.The Liuweidihuang pill was used as a model formulation.The multi-component release kinetics of the concentrated and water-honeyed Liuweidihuang pills at rotation speeds of 50 and 100 rpm were analyzed by chemomic release kinetic theory and modified LC/MS/MS method.Mass features of 103(concentrated pills)and 101(water-honeyed pills)were selected with a linear correlation coefficient Z0.99 between mass responses and concentrations.To compose the chemomic standard spectrum,the relative abundance of both mass features was no less than 1%as compared with an internal standard.The correlation coefficients between six samples of various solutions were in line with analytical requirements of precision(rZ0.985).The score plots of principal component analysis showed that the concentrated Liuweidihuang pills presented better chemomic release reproducibility than the water-honeyed pills.Conversely,the impact of rotation speed on the chemomic release was less obvious.The heat maps of hierarchical clustering analysis did not show significant changes in individual clusters of mass features along different time intervals,reflecting the release integrity of the mass features.Therefore,both multivariate analysis methods,the principal component analysis and the hierarchical clustering analysis,seemed to be effective techniques to demonstrate the multiple component release performance of TCM.The research provided the basis of a new strategy for the quality control procedures of the dissolution/release for the traditional medicine and multi-component natural products to address increasing regulatory requirements and scrutiny across the world.

Fast Quantification of the Mixture of Polycyclic Aromatic Hydrocarbons Using Surface-Enhanced Raman Spectroscopy Combined with PLS-GA-BP Network

To realize the fast and accurate quantitative analysis of the mixture of polycyclic aromatic hydrocarbons(PAHs),surface-enhanced Raman spectroscopy(SERS)coupled with multivariate calibrations were employed.In this study,three kinds of calibration algorithms were used to quantitative analysis of the mixture of naphthalene(Nap),phenanthrene(Phe),and pyrene(Pyr).Firstly,partial least squares(PLS)algorithm was used to select characteristic variables,then the global search capability of genetic algorithm(GA)was used for the determining of the initial weights and thresholds of back propagation(BP)neural network so that local minima was avoided.The PLS-GA-BP model exhibited superiority to quantify PAHs mixture,which achieved R2=0.9975,0.9710,0.9643,ARE=10.07%,19.28%,16.72%and RMSE=13.10,5.40,5.10 nmol L−1 for Nap,Phe,Pyr(in the PAHs mixture)concentration prediction respectively.The forecast error,ARE and RMSE have been reduced more than 50%and 60%respectively compared with the whole spectral BP model.The study indicates that accurate quantitative spectroscopic analysis of the mixture of PAHs samples can be achieved through the combination of SERS technique and PLS-GA-BP algorithm.

Application of Fingerprint Combined with QAMS in Quality Evaluation of Zhenrongdan Mixture

[Objectives] The research aimed to evaluate the quality of Zhenrongdan mixture by fingerprint combining QAMS. [Methods] The quality evaluation method was established and validated with echinacoside as internal reference to determine the contents of other components(ferulic acid, salvianolic acid B, and icariin) according to the relative correction factor. The accuracy and feasibility of QAMS were evaluated by comparison on the results between the measured value and calculation value by external standard method and QAMS. [Results] A common pattern of characteristic fingerprint of Zhenrongdan mixture by HPLC was established. Thirteen common peaks were identified, and they account for 91% of the total peak area, and four components were verified in five batches of Zhenrongdan mixture. Good similarities with correlation coefficients higher than 0.99 were found in the fingerprints. There was no significant difference between the quantitative results of the four ingredients in the five batches by external standard method and QAMS. [Conclusions] The method of fingerprint combined with QAMS could be used for the quality control of multiple components determination and fingerprint chromatography for Zhenrongdan mixture.

Simultaneous Determination of Five Components in Operculina turpethum

[Objectives]This study was conducted to establish a method for the simultaneous determination of caffeic acid, rutin, ononin, luteolin, and apigenin in Operculina turpethum(L.) S. Manso. [Methods]With ononin from O. turpethum as the internal reference, the five components were separated by HPLC, and the contents of various components were calculated according to the relative correction factors of ononin with caffeic acid, rutin, luteolin, and apigenin. Meanwhile, the calculated results of quantitative analysis of multi-components by single marker(QAMS) were compared with the determined values of the external standard method. [Results] The linear relationship of the five components in their respective ranges was good(r=0.999 9). The average recovery was in the range of 97.48%-101.05%, and the RSD values were in the range of 1.04%-2.71%. The results obtained by QAMS were close to those obtained by the external standard method. [Conclusions] The method is accurate, stable and adaptable, and can be used for the determination of five flavonoids in O. turpethum.

A Quantitative Method for Simultaneous Determination of Four Anthraquinones with One Marker in Rhei Radix et Rhizoma

Objective To develop a quantitative method for simultaneously determining multi-components in Rhei Radix et Rhizoma using one chemical reference substance.Methods The contents of multi-components were calculated by the UV relative correction factors(RCFs)of chrysophanol,physcion,and rhein to emodin.Results The values of RCFs at 274 nm for rhein,chrysophanol,and physcion to emodin were 0.712,0.674,and 1.051.The calibration curves were linear over the ranges of 0.02-4.08,0.02-4.12,0.07-12.92,and 0.02-3.68μg/mL for rhein,emodin, chrysophanol,and physcion,respectively.The contents of emodin in 18 samples were determined by the external standard method,and the contents of the other three anthraquinone aglycones were calculated according to their RCFs. Conclusion No significant difference is found in comparison with the classical method,indicating that the RCFs have high reliability within their linear ranges and could be used in quality control of Rhei Radix et Rhizoma.The quantitative analysis of multi-component with a single marker is especially suitable for herbal medicines containing unstable or hard to be purified components as quality control markers.

Overview of the quality standard research of traditional Chinese medicine

Traditional Chinese medicine(TCM)has been widely used for the prevention and treatment of various diseases for a long time in China.Due to its proven efficacy,wide applications,and low side effect,TCM has increasingly attracted worldwide attention.However,one of the biggest challenges facing the clinical practice of TCM is the uncontrollable quality.In this review,the progress of the development and the current status of quality standard as well as new quality control techniques introduced in Chinese Pharmacopoeia(2010 edition),such as liquid chromatography hyphenated mass spectrometry(LC-MS),fingerprint,quantitative analysis of multi-components by single-marker(QAMS),thin layer chromatography bio-autographic assay(TLC-BAA),and DNA molecular marker technique,are briefly overviewed.