Dynamics of Multi-Stage Bladed Disks Systems

This paper presents a new and original method for dynamical analysis of multistage cyclic structures such as turbomachinery compressors or turbines. Each stage is modeled cyclically by its elementary sector and the interstage coupling is achieved through a cyclic recombination of the interface degrees of freedom. This method is quite simple to set up; it allows us to handle the finite element models of each stage's sector directly and, as in classical cyclic symmetry analysis, to study the nodal diameter problems separately. The method is first validated on a simple case study which shows good agreements with a complete 360 deg reference calculation. An industrial example involving two HP compressor stages is then presented. Then the forced response application is presented in which synchronous engine order type excitations are considered.

Analysis of Saponins from Leaves of Aralia elata by Liquid Chromatography and Multi-stage Tandem Mass Spectrometry

Four saponins were isolated from the leaves of Aralia elata, and established using NMR and other spectroscopic methods, as well as data reported in the literature. Three Aralia saponins from the leaves of Aralia elata sharing the same structures as those isolated from the root bark suggested that the leaves would be a good substitute for the root bark of Aralia elata. These four Aralia saponins were then extensively investigated using complementarily positive and negative electrospray ionization multistage tandem mass spectrometry (ESI-MSn). Two isomers of saponins with different sugar linkages were then successfully differentiated by positive ESI-MSn and verified with different retention times and the collision-induced dissociation (CID) spectra by LC-MS. A simple and effective LC-MS method was thus developed for the rapid identification and screening of these saponins in plant extracts from leaves of Aralia elata.

Analysis of strychnos alkaloids using electrospray ionization Fourier transform ion cyclotron resonance multi-stage tandem mass spectrometry

The fragmentations of four strychnos alkaloids have been investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) in the positive ion mode. Experiments using multi-stage tandem mass spectrometry (ESI-FT-ICR-MSn) allowed us to obtain precise elemental compositions of product ions at high mass resolution. The experimental data demonstrated that the nitrogen bridge and the coordinated oxygen atom on the nitrogen bridge in the alkaloid compounds were the active sites in the MS2 fragmentations. The loss of CH3 or the OCH3 group in those alkaloids, which have an OCH3 substituent, was the dominant fragmentation mode in the MS3 fragmentations. Logical fragmentation schemes for strychnos alkaloids have been proposed and these should be useful for the identification of these compounds.

Rapid identification of saponins in plant extracts by electrospray ionization multi-stage tandem mass spectrometry and liquid chromatography/tandem mass spectrometry

Electrospray ionization multi-stage tandem mass spectrometry (ESI-MSn) and liquid chromatography coupled with on-line mass spectrometry (LC/MS/MS) were applied to characterize saponins in crude extracts from Panax ginseng. The MSn data of the [M - H](-) ions of saponins can provide structural information on the sugar sequences of the saccharide chains and on the sapogins of saponins. By ESI-MSn, non-isomeric saponins and isomeric saponins with different aglycones can be determined rapidly in plant extracts. LC/MS/MS is a good complementary analytical tool for determination of isomeric saponins. These approaches constitute powerful analytical tools far rapid screening and structural assignment of saponins in plant extracts. Copyright (C) 2000 John Wiley & Sons, Ltd.

Metal ion adducts in the structural analysis of ginsenosides by electrospray ionization with multi-stage mass spectrometry

The effect of metal (Li+, Na+, K+, Ag+) cationization on collision-induced dissociation of ginsenosides was investigated by electrospray ionization mass spectrometry combined with multi-stage mass spectrometry (ESI-MSn). The fragments of sodiated and lithiated molecules give valuable structural information regarding the nature of the aglycone and the sequence and linkage information of sugar moieties. However, the number and relative abundances of fragment ions from lithiated ginsenosides are significantly greater than for the sodiated species, The K+ adducts undergo glycosidic cleavages and very limited cross-ring reactions. The silver ion adducts fragment mainly through glycosidic cleavages. Copyright (C) 2001 John Wiley & Sons, Ltd.

Multi-stage mass spectrometric studies of triterpenoid saponins in crude extracts from Acanthopanax senticosus harms

Three triterpenoid saponins in crude extracts from Acanthopanax senticosus Harms have been investigated by use of multi-stage mass spectrometry (MSn) combined with electrospray ionization (ESI), MSn spectra were applied to direct structure elucidation of these saponins in crude plant extracts, in positive and negative ion mode. The characteristic fragmentations of triterpenoid saponins are discussed. The method provides a means of rapid initial screening of crude plant extracts. Copyright (C) 1999 John Wiley & Sons, Ltd.

On the Evolution of Simple Shear in Saturated Soils

Development of shear bands in saturated soils is a multi-stage process based on the theoretical and numerical investigations in this paper. The soil is initially in homogenous shear strain state, and the instability can be characterized by a dimensionless number D. The inhomogenous distribution of shear strains appears when D>1, and the shear band will initiate and develop gradually. Numerical solutions show that only single shear band that is finally formed in the central region of the specimen even several disturbances (distributed along the specimen) appear in the beginning.

混合模式识别系统研究

讨论基于多种分类方法的模块组合实现的混合模式识别系统，它不同于利用多分类器输出结果表决的集成系统．提出两个系统：一个面向印刷体汉字文本识别，另一个面向自由手写体数字识别．利用多种特征和多种分类方法的组合、部分识别信息控制混淆字判别策略以及提出的动态模板库匹配后处理方法，使系统的性能与传统单一分类器系统比较，获得明显改善．实验表明：多方法多策略混合是解决复杂和增强系统鲁棒性的一条途径

中祁连花岗岩年代学、地球化学及其构造意义

The Qilian Orogenic Belts had undergone very complicated evolutional histories and play an important role in understanding the tectonic evolutions of old terrains in northwestern China, in which granitiods formed during Proterozoic-early Mesozoic are widely outcropped. Detailed studies of these granitiods can shed some light on the tectonic evolution of this region. In this thesis, we have conducted geochronological and geochemical studies on eight selected granitic plutons to unravel their emplacement ages and petrogenesis. Furthermore, their tectonic implications were also discussed based on these results. In Neo-Proterozoic, our results suggest that two stages of magmatic activities were taken place in Central Qilian Block, GroupⅠ(750-790Ma) and Group Ⅱ(845－ 930Ma). In Neo-Paleozoic, most granitic plutons were emplaced from Ordovician to Devonian, whereas granitiods with Triassic ages have also been discovered in South Qilian Belt. Inherited zircons with old ages of 1.7Ga, 2.1Ga and 2.7Ga have also been obtained in our study. Geochemical studies suggest that the Proterzoic granites were produced under high pressures and low temperatures from metamorphosed protolith rocks with compostions from basic to intermediate. This implies that some hot sources were underplated beneath lithosophere via mantle-derived magmatism. In combination with regional geological data, we propose that the Cental Qilian block was an old arc terrene during Precambrian, and two stage granitoids were formed under a back-arc extensional setting. Granitic rocks emplaced in early Paleozoic belong to strong peraluminous S-type granites, which were derived from metagreywacke having strong relationships with collisional process. Together with previous data, our results indicate that granitoids in Qilian Orogenic Belt formed during early Paleozoic have different petrogenesis and emplaced ages, which reflect that Qilian Orogenic Belt had underwent complicated multi-stage subduction-collusional processes in early Paleozoic. On the other hand, granitic rocks in South Qilian Belt with Triassic ages were formed by subduction of East Kulun during early Paleozoic-Late Mesozoic, which represent another orogenic episode in the northern margin of Tibetan Plateau.

东海陆架盆地西南部烟囱构造与油气运聚关系研究

In recent years, chimney structure has been proved one of important indicators and a useful guide to major petroleum fields exploration through their exploration history both at home and abroad. Chimney structure, which has been called "gas chimney" or "seismic chimney", is the special fluid-filled fracture swarm, which results from the boiling of active thermal fluid caused by abruptly decreasing of high pressure and high temperature in sedimentary layers of upper lithosphere. Chimney structure is well developed in continental shelf basin of East China Sea, which indicates the great perspectives of petroleum resources there. However, the chimney structure also complicated the petroleum accumulation. So the study of chimney structure on its formation, its effect on occurrence and distribution of petroleum fields is very important not only on theoretical, but also on its applied research. It is for the first time to make a clear definition of chimney structure in this paper, and the existence and practical meaning of chimney structure are illustrated. Firstly, on the viewpoint of exploration, this will amplify exploration area or field, not only in marine, but also on continent. Secondly, this is very important to step-by-step exploration and development of petroleum fields with overpressure. Thirdly, this will provide reference for the study on complex petroleum system with multi-sources, commingled sources and accumulation, multi-stage accumulations, and multi-suits petroleum system in the overlay basin. Fourthly, when the thermal fluid enters the oceanic shallow layer, it can help form gas hydrate under favorable low-temperature and high-pressure conditions. Meanwhile, the thermal fluid with its particular component and thermal content will affect the physical, chemical and ecological environments, which will help solving the problem of global resources and environment. Beginning from the regional tectonic evolution characteristics, this paper discussed the tectonic evolution history of the Taibei depression, then made an dynamical analysis of the tectonic-sedimentary evolution during the Mesozoic and Cenozoic for the East China Sea basin. A numerical model of the tectonic-thermal evolution of the basin via the Basin-Mod technique was carried out and the subsidence-buried history and thermal history of the Taibei depression were inverse calculated: it had undergone a early rapid rift and sag, then three times of uplift and erosion, and finally depressed and been buried. The Taibei depression contains a huge thick clastic sedimentary rock of marine facies, transitional facies and continental facies on the complex basement of ante-Jurassic. It is a part of the back-arc rifting basins occurred during the Mesozoic and Cenozoic. The author analyzed the diagenesis and thermal fluid evolution of this area via the observation of cathodoluminescence, scanning electron microscope and thin section, taking advantage of the evidences of magma activities, paleo-geothermics and structural movement, the author concluded that there were at least three tectonic-thermal events and three epochs of thermal-fluid activities; and the three epochs of thermal-fluid activities were directly relative to the first two tectonic-thermal events and were controlled by the generation and expulsion of hydrocarbon in the source rock simultaneously. Based on these, this paper established the corresponding model between the tectonic-thermal events and the thermal-fluid evolution of the Taibei Depression, which becomes the base for the study on the chimney structures. According to the analyses of the gas-isotope, LAM spectrum component of fluid inclusion, geneses of CO_2 components and geneses of hydrocarbon gases, the author preliminarily verified four sources of the thermal fluid in the Taibei Depression: ① dehydration of mud shale compaction, ② expulsion of hydrocarbon in the source rock; ③ CO_2 gas hydro-thermal decomposition of carbonatite; ④magma-derived thermal fluid including the mantle magma water and volatile components (such as H_2O, CO_2, H_2S, SO_2, N_2 and He etc.). On the basis of the vitrinite reflectance (Ro), homogenization temperature of fluid inclusion, interval transit time of major well-logging, mud density of the wells, measured pressure data and the results of previous studies, this paper analyzed the characteristics of the geothermal fields and geo-pressure fields for the various parts in this area, and discussed the transversal distribution of fluid pressure. The Taibei depression on the whole underwent a temperature-loss process from hot basin to cold basin; and locally high thermal anomalies occurred on the regional background of moderate thermal structure. The seal was primarily formed during the middle and late Paleocene. The overpressured system was formed during the middle and late Eocene. The formation of overpressured system in Lishui Sag underwent such an evolutionary process as "form-weaken-strengthen-weaken". Namely, it was formed during the middle and late Eocene, then was weakened in the Oligocene, even partly broken, then strengthened after the Miocene, and finally weakened. The existence of the thermal fluid rich in volatile gas is a physical foundation for the boiling of the fluid, and sharply pressure depletion was the major cause for the boiling of the fluid, which suggests that there exists the condition for thermal fluid to boil. According to the results of the photoelastic simulation and similarity physical experiments, the geological condition and the formation mechanism of chimnestructures are summarized: well compartment is the prerequisite for chimney formation; the boiling of active thermal fluid is the original physical condition for chimney formation; The local place with low stress by tension fault is easy for chimney formation; The way that thermal fluid migrates is one of the important factors which control the types of chimney structures. Based on where the thermal fluid come from and geometrical characteristics of the chimney structures, this paper classified the genetic types of chimney structures, and concluded that there existed three types and six subtypes chimney structures: organic chimney structures generated by the hydrocarbon-bearing thermal fluid in middle-shallow layers, inorganic and commingling-genetic chimney structures generated by thermal fluid in middle-deep layers. According to the seismic profiles interpretations, well logging response analysis and mineralogical and petrological characteristics in the study area, the author summarized the comprehensive identification marks for chimney structures. Especially the horizon velocity analysis method that is established in this paper and takes advantage of interval velocity anomaly is a semi-quantitative and reliable method of chimney structure s identification. It was pointed out in this paper that the occurrence of the chimney structures in the Taibei depression made the mechanism of accumulation complicated. The author provided proof of episodic accumulation of hydrocarbon in this area: The organic component in the boiling inclusion is the trail of petroleum migration, showing the causality between the boiling of thermal fluid and the chimney structures, meanwhile showing the paroxysmal accumulation is an important petroleum accumulation model. Based on the evolutionary characteristics of various types of chimney structures, this paper discussed their relationships with the migration-accumulation of petroleum respectively. At the same time, the author summarized the accumulating-dynamical models associated with chimney structures. The author analyzed such accumulation mechanisms as the facies state, direction, power of petroleum migration, the conditions of trap, the accumulation, leakage and reservation of petroleum, and the distribution rule of petroleum. The author also provides explanation for such practical problems the existence of a lot of mantle-derived CO_2, and its heterogeneous distribution on plane. By study on and recognition for chimney structure, the existence and distribution of much mantle-derived CO_2 found in this area are explained. Caused by tectonic thermal activities, the deep magma with much CO_2-bearing thermal fluid migrate upward along deep fault and chimney structures, which makes two wells within relatively short distance different gas composition, such as in well LF-1 and well LS36-1-1. Meanwhile, the author predicted the distribution of petroleum accumulation belt in middle-shallow layer for this area, pointed out the three favorable exploration areas in future, and provided the scientific and deciding references for future study on the commingling-genetic accumulation of petroleum in middle-deep layer and the new energy-gas hydrate.