层状反倾向结构岩质边坡变形机理及稳定性研究

Toppling is a major failure model in anti-dip layered rock slopes. Because of the limited by testing means and experimental apparatus, present research on the deformation mechanism and stability analysis are mainly focus on the 2-Dimensional deformation, and the research really based on 3-Dimension is still limited. Therefore, based on the present research station, the article rely on the important hydroelectric project of typical anti-dip layered rock slopes -- The left bank slope of Long-tan hydropower-station in Guang Xi, China, and focused on the influencing factors, deformation mechanism and stability analysis of anti-dip layered rock slopes, three problems as follows are researched in this paper. (1) Deformation influencing factor analysis on ant-dip layered rock slopes Three influencing factors are included: geological factor, engineering factor and environmental factor. It is concluded that the toppling deformation of anti-dip layered rock slopes are more sensitive to geological and engineering factors, but less sensitive to environmental factor. In addition, the sensitivity of various factors to the rock toppling deformation is also arranged sequentially as follows: construction, gravitation, rainfall (underground water) and rock structure intensity, etc. (2) 3D deformation study on the anti-dip layered toppling rock slopes Used 3D Distinct Element Method (3DEC) analyzed the 3D deformation characteristic of anti-dip layered rock slops. It can be seen that the toppling characteristics are obvious when the inter-angle between slope direction and layer striking direction is under 20o, when the inter-angle is over 20o and equal or less than 40o，the toppling deformation characteristics decrease sharply with increase of inter-angle, when the inter-angle is over 40o , the slope deformation is not controlled by joints but influenced by other failure mode. Therefore, in order to quantify the toppling characteristics, a differential value of displacement vector angle between layered rock slope and block rock slope is proposed as a key index to distinguish failure model for anti-dip layered rock slopes, and it was applied to study the toppling of the rock slopes at Guangxi Long-tan hydropower station, China. The results indicated that the index was effective and instructive for analyzing the anti-dip layered rock slopes. (3) Stability analysis methods Because of the imperfection of some present slope analysis methods, based on slope failure mode and those three influencing factors, “slope stability entropy” method is defined in this paper, which makes good use of the sensitivity of relational matrix to influencing factors on slope stability and the qualification characteristics for information entropy to the irregularity of slope deformation. By this method, not only the randomness of geologic body on the base of dynamic analysis of slope failure mode is fully concerned, but also it makes the analysis time-saving and simple. Finally, the research findings were used to the engineering example successfully, and rational conclusion has been obtained.

电离层行进式扰动的GPS台网监测研究

In this dissertation, we investigated two types of traveling ionospheric disturbances (TIDs)/gravity waves (GWs) triggered separately by auroral energy input during super geomagnetic storms and solar terminator (ST) under quiet geomagnetic conditions (kp<3+) using TEC measurements from the global network of GPS receivers. Research into the generation and propagation of TIDs/GWs during storms greatly enhance our understandings on the evolution processes of energy transportation from the high-latitude’s magnetosphere to the low-latitude ionosphere and the conjugated effect of TIDs propagation between the northern and southern hemispheres. Our results revealed that the conjugacy of propagation direction between the northern and southern hemispheres was subject to the influence of Coriolis force. We also figure out the evolution processes of ionospheric disturbances at the global scale. These are important topics that had not been well addressed previously. In addition, we also obtained thee wave structures of medium scale TIDs excited by the solar terminator (ST) moving over the northern America and physical mechanisms involved. Our observations confirm that the ST is a stable and repetitive source of ionospheric wave disturbances and the evidence of solar terminator generated disturbances has been demonstrated experimentally via the GPS TEC measurement. The main researches and results of this dissertation are as follows. First, the global traveling ionospheric disturbances (TIDs) during the drastic magnetic storms of October 29–31, 2003 were analyzed using the Global Position System (GPS) total electron content (TEC) data observed in the Asian-Australian, European and North American sectors. We collected the most comprehensive set of the TEC data from more than 900 GPS stations on the International GNSS Services (IGS) website and introduce here a strategy that combines polynomial fitting and multi-channel maximum entropy spectral analysis to obtain TID parameters. Moreover, in collaboration with my thesis advisor, I have developed an imaging technique of 2-dimensional map of TIDs structures to obtain spatial and temporal maps of large scale traveling ionospheric disturbances (LSTIDs). The clear structures of TEC perturbations map during the passage of TIDs were displayed. The results of our study are summarized as follows: (1) Large-scale TIDs (LSTIDs) and medium-scale TIDs (MSTIDs) were detected in all three sectors after the sudden commencement (SC) of the magnetic storm, and their features showed longitudinal and latitudinal dependences. The duration of TIDs was longer at higher latitudes than at middle latitudes, with a maximum of about 16 h. The TEC variation amplitude of LSTIDs was larger in the North American sector than in the two other sectors. At the lower latitudes, the ionospheric perturbations were more complicated, and their duration and amplitude were relatively longer and larger. (2) The periods and phase speeds of TIDs were different in these three sectors. In Europe, the TIDs propagated southward; in North America and Asia, the TIDs propagated southwestward; in the near-equator region, the disturbances propagated with the azimuth (the angle of the propagation direction of the LSTIDs measured clockwise from due north with 0°) of 210° showing the influence of Coriolis force; in the Southern Hemisphere, the LSTIDs propagated conjugatedly northwestward. Both the southwestward and northeastward propagating LSTIDs are found in the equatorial region. These results mean that the Coriolis effect cannot be ignored for the wave propagation of LSTIDs and that the propagation direction is correlated with the polar magnetic activity. (3) The day (day of year: 301) before the SC (sudden commencement) of magnetic storm, we observed a sudden TEC skip disturbances (±10 TECU). It should be a response for the high flux of proton during the solar flare event, but not the magnetic storms. Next, the most comprehensive and dense GPS network’s data from North-America region were used in this paper to analyze the medium scale traveling ionospheric disturbances (MSTIDs) which were generated by the moving solar terminator during the quiet days in 2005. We applied the multi-channel maximum entropy spectral analysis to calculated TID parameters, and found that the occurrence of ST-MSTIDs depends on the seasonal variations. The results of our study are summarized as follows: (1) MSTIDs stimulated by the moving ST (ST-MSTIDs) are detected at mid-latitudes after the passage of the solar terminator with the life time of 2～3 hours and the variation amplitude of 0.2～0.8 TECU. Spectral analysis indicated that the horizontal wavelength, average period, horizontal phase velocity of the MSTIDs are around 300±150 km，150±80 m/s and 25±15 min, respectively. In addition, ST-MSTIDs have wave fronts elongating the moving ST direction and almost parallel to ST. (2) The statistical results demonstrate that the dusk MSTIDs stimulated by ST is more obvious than the dawn MSTIDs in summer. On the contrary, the more-pronounced dawn MSTIDs occurs in winter. (3) Further analysis indicates that the seasonal variations of ST-MSTIDs occurrence frequency are most probably related to the seasonal differences of the variations of EUV flux in the ionosphere region and recombination process during sunrise and sunset period at mid-latitudes. Statistical study of occurrence characteristics of TIDs using the GPS network in North-American and European during solar maximum, In conclusion, statistical studies of the propagation characteristics of TIDs, which excited by the two common origins including geomagnetic storms and moving solar terminator, were involved with global GPS TEC databasein this thesis. We employed the multichannel maximum entropy spectral analysis method to diagnose the characteristics of propagation and evolvement of ionospheric disturbances, also, the characteristics of their regional distribution and climatological variations were revealed by the statistic analysis. The results of these studies can improve our knowledge about the energy transfer in the solar-terrestrial system and the coupling process between upper and lower atmosphere (thermosphere-ionosphere-mesosphere). On the other hand, our results of the investigation on TIDs generated by particular linear origin such as ST are important for developing ionospheric irregularity physics and modeling the transionosphere radio wave propagation. Besides, the GPS TEC representation of the ST-generated ionospheric structure suggests a better possibility for investigating this phenomenon. Subsequently, there are scientific meaning of the result of this dissertation to deeply discuss the energy transfer and coupling in the ionosphere, as well as realistic value to space weather forecast in the ionosphere region.

利用接收函数方位变化研究地壳各向异性

Because of its sensitivity to the velocity discontinuity of the earth, receiver function technique has become a routine procedure used to probe interior structure of the earth. Receiver functions contain anisotropic information of the earth’s interior, however, traditional receiver function techniques such as migration imaging and waveform inversion method, which are based on isotropic media assumption, can not effectively extract the anisotropy information contained in the azimuth variation pattern. Only by using the anisotropic media, e.g. a model with symmetric axis of arbitrary orientation, computing the response, can we obtain the detailed anisotropy information hidden in the radial and transversal receiver function. Focusing on the receiver function variation pattern changing wtih different back azimuths, we introduced different kinds of symmetric systems of seismic anisotropy used often, and summarized some possible causes of anisotropy formation. We show details about how to calculate the response of a stratified anisotropy model with symmetric axis of arbitrary orientation. We also simulated receiver functions among different models and analyzed how the changing of anisotropic parameters influence the azimuth variation pattern of receiver functions. The anisotropy study by receiver function analysis was applied to Taihang Mountain Range (TMR) in North China in this thesis. The maximum entropy spectrum deconvolution technique was used to extract radial and transversal receiver functions from the waveforms of 20 portable seismic stations deployed in TMR. Considering the signal-to-noise ratio and the azimuth coverage, we got the variation pattern of receiver functions for 11 stations. After carefully analyzing the pattern of the receiver functions that we got, we obtained the reliable evidence on the existence of anisotropy in the shallow crust in TMR. Our results show that, although the thickness of the upper crustal layer is only about 1 km, the layer shows a strong anisotropy with magnitude of 8~15%; in the deeper of crust, the magnitudes of anisotropy is about 3%~5%, showing a pattern with fast-symmetric-axis. The crust anisotropy beneath TMR in North China obtained in this study also shows a significant difference in both the lateral and vertical scale, which might imply a regional anisotropy characteristic in the studied region.

岩体力学参数及稳定性能量判据研究

There are two major problems that have been concerned all the times, which are the mechanics characters of joint rock mass and the criterion for stability of engineering rock. Aim at the two problems, several works were conducted as follow: (1) Firstly, the mechanics characters of rock mass was studied by means of the Distinct Element Code. Subsequently, it was studied that the sensibility of joint surface roughness, strength of joint wall, joint stiffness ( i.e. tangential and normal stiffness) on the rock mass strength. (2) Based on the experimental rock mass classification methods of RMR and GSI, the program of “Parameters Calculation of the Rock Mass ” was developed. It has realized the rapid choice of rock mass parameters. (3) The concept of Representive Element Volume was induced based on the study of dimensional effect of rock mass. The Representive Element Volume of the horizontal and vertical pillar (ab. Two Pillars ) in the 2nd zone of Jinchuan mine were gained by the Geology Statistic Method and the Distinct Element Code. And then, the strength and deformatiom parameters of rock mass of the Two Pillars were obtained through numerical experiment. (4) From the confining depressure after thriaxial compression test of rock sample, it was concluded that the failure of rock is caused mainly by the lateral deformation and energy release happened during the confining depressure processure. The criterion of plastic energy catastrophe of rock engineering failure was proposed and validated. Subsquently, the stability of the horizontal pillar and Qianjiangping landslide in Three Gorges was judged by means of above-mentioned method. (5) Based on the fact there is a phenomenon of increasing energy concentration while the rock mass was compressed, rock information entropy (i.e. energy distribution entropy) was proposed. And it was revealed that there was change of energy distribution entropy while the rock mass was compressed to failure.

通过第一性原理计算研究内地核的结构与成分

The determination of the composition and structure of the Earth’s inner core has long been the major subject in the study of the Earth’s deep interior. It’s widely believed that the Earth’s core is formed by iron with a fraction of nickel. However, light elements must exist in the inner core because the earth core is less dense than pure iron-nickel alloy (~2-3% in the solid inner core and ~6-7% in the liquid outer core). The questions are what and how much light element is there in the iron-nickel alloy. Besides the composition, the crystal structure of the iron with or without light element is also not well known. According to the seismological observations, the sound waves propagate 3-4% faster along the spin axis than in the equatorial plane. That means the inner core is anisotropic. The densest structure of iron-nickel alloy should be h.c.p structure under the very high pressures. However, the h,c,p structure does not propagate waves anisotropic ally. Then what is the structure of the iron-nickel alloy or the iron-nickle-light element alloy. In this study, we tried to predict the composition and the structure of the inner core through ab initio calculation of the Gibbs free energy, which is a function of internal energy, density and entropy. We conclude that the h.c.p structure is more stable than the b.c.c structure under high pressure and 0 K, but with the increase of temperature, the free energy of the b.c.c structure is decreasing much faster than the h.c.p structure caused by the vibration of the atomics, so the b.c.c structure is more stable at high temperatures. With the addition of light elements (S or Si or both), the free energy of b.c.c. decreases even faster, about 3at% of Si not only explains why the inner core is about 2-3 % lighter than the iron-nickle alloy, but also reasons why the inner core is anisotropic, since the b.c.c. structure becomes more stable than the h.c.p structure at 5500-6000K and b.c.c. is anisotropic in propagating seismic waves. Therefore, we infer that the inner core of the earth is formed by b.c.c iron and a fraction of nickel plus ~3at.% Si, with a temperature higher than 5500K, which is consistent with the studies from other approaches.

城市发展与地质环境相互作用机制及数量分析—北海市可持续发展战略研究

Based on a viewpoint of an intricate system demanding high, this thesis advances a new concept that urban sustainable development stratagem is a high harmony and amalgamation among urban economy, geo-environment and tech-capital, and the optimum field of which lies in their mutual matching part, which quantitatively demarcates the optimum value field of urban sustainable development and establishes the academic foundation to describe and analyze sustainable development stratagem. And establishes a series of cause-effect model, a analysissitus model, flux model as well as its recognizing mode for urban system are established by the approach of System Dynamics, which can distinguish urban states by its polarity of entropy flows. At the same time, the matter flow, energy flow and information flow which exist in the course of urban development are analyzed based on the input/output (I/O) relationships of urban economy. And a new type of I/O relationships, namely new resources-environment account, are established, in which both resource and environment factors are considered. All above that settles a theoretic foundation for resource economy and environment economy as well as quantitative relationships of inter-function between urban development and geoenvironment, and gives a new approach to analyze natinal economy and urban sustainable development. Based on an analysis of the connection between resource-environmental construct of geoenvironment and urban economy development, the Geoenvironmental Carrying Capability (GeCC) is analyzed. Further more, a series of definitions and formula about the Gross Carrying Capability (GCC), Structure Carrying Capability (SCC) and Impulse Carrying Capability (ICC) is achieved, which can be applied to evaluate both the quality and capacity of geoenvironment and thereunder to determine the scale and velocity for urban development. A demonstrative study of the above is applied to Beihai city (Guangxi province, PRC), and the numerical value laws between the urban development and its geoenvironment is studied by the I/O relationship in the urban economy as following: · the relationships between the urban economic development and land use as well as consumption of underground water, metal mineral, mineral energy source, metalloid mineral and other geologic resources. · the relationships between urban economy and waste output such as industrial "3 waste", dust, rubbish and living polluted water as well as the restricting impact of both resource-environmental factors and tech-capital on the urban grow. · Optimization and control analysis on the reciprocity between urban economy and its geoenvironment are discussed, and sensitive factors and its order of the urban geoenvironmental resources, wastes and economic sections are fixed, which can be applied to determine the urban industrial structure, scale, grow rate matching with its geoenvironment and tech-capital. · a sustainable development stratagem for the city is suggested.

中新世秦安黄土一古土壤序列记录的古气候变化周期

Analysis of periodic oscillations of climate is very important in understanding the behavior of the climate system. Milankovitch hypothesis, which holds that the glacial-interglacial climatic cycles during the Quaternary were primarily driven by variations in orbital parameters, has been supported by substantial geological evidence. Continuous long-term and high-resolution records are crucial to detect how variations of Earth's orbital parameters affected climate before the Quaternary when the boundary conditions were significantly different. Qinan loess formed in the Miocene is nearly continuous aeolian deposit in northern China. Previous study has established a constrained chronology, which provides a basis to examine long-term climatic variations. One of important issues to untangle the mechanisms behind major climate changes is the investigation of climate cycles recorded in Qinan loess. In this paper, two climatic proxies, magnetic susceptibility and redness, are analyzed for QA-I section to evaluate climate cycles using Maximum entropy spectral analysis and Blackman-Tuckey method. Main conclusions are presented as following: Results exhibit significant peaks at periods of 100 ka, 64 ka, 41 ka, 30 ka and 23 ka, but also 1000 ka, 600 ka and 400 ka. These peaks correspond to the dominant periods of the Earth's orbit parameters, which indicates that the formation of the aeolian sediment in northern China might be primarily driven by variations in orbital parameters. Fluctuations with different cycles respectively dominated in different periods. Major shifts in the dominant cycles occurred at 20.3, 19.0, 17.9, 15.2, 12.5 and 11.3 Myr ago. The transition that happened at 17.9 Myr ago was synchronous with the uplift of the Tibetan Plateau, while others at 15.2, 12.5 and 11.3 Myr ago were in good agreement with the timing of the development of Antarctic ice sheet. Therefore we inferred that these shifts might be related to changes in global ice volume and/or the Tibetan uplift. 3. The strong period of 100 ka is observed between 17.9 and 15.2, and 12.5 and 11.3 Myr ago. Ice sheet-climate models that have been used to explain the cause of the 100 ka period since the middle Pleistocene couldn't be responsible for driving the 100 ka climate cycle in the Miocene in Northern China because of the different boundary of climatic conditions between the Quaternary and Miocene. Further investigation is needed to understand how this cycle became dominant in Qinan loess records during these two time segments.

基于信息重建技术的地震信号处理方法研究

The dissertation addressed the problems of signals reconstruction and data restoration in seismic data processing, which takes the representation methods of signal as the main clue, and take the seismic information reconstruction (signals separation and trace interpolation) as the core. On the natural bases signal representation, I present the ICA fundamentals, algorithms and its original applications to nature earth quake signals separation and survey seismic signals separation. On determinative bases signal representation, the paper proposed seismic dada reconstruction least square inversion regularization methods, sparseness constraints, pre-conditioned conjugate gradient methods, and their applications to seismic de-convolution, Radon transformation, et. al. The core contents are about de-alias uneven seismic data reconstruction algorithm and its application to seismic interpolation. Although the dissertation discussed two cases of signal representation, they can be integrated into one frame, because they both deal with the signals or information restoration, the former reconstructing original signals from mixed signals, the later reconstructing whole data from sparse or irregular data. The goal of them is same to provide pre-processing methods and post-processing method for seismic pre-stack depth migration. ICA can separate the original signals from mixed signals by them, or abstract the basic structure from analyzed data. I surveyed the fundamental, algorithms and applications of ICA. Compared with KL transformation, I proposed the independent components transformation concept (ICT). On basis of the ne-entropy measurement of independence, I implemented the FastICA and improved it by covariance matrix. By analyzing the characteristics of the seismic signals, I introduced ICA into seismic signal processing firstly in Geophysical community, and implemented the noise separation from seismic signal. Synthetic and real data examples show the usability of ICA to seismic signal processing and initial effects are achieved. The application of ICA to separation quake conversion wave from multiple in sedimentary area is made, which demonstrates good effects, so more reasonable interpretation of underground un-continuity is got. The results show the perspective of application of ICA to Geophysical signal processing. By virtue of the relationship between ICA and Blind Deconvolution , I surveyed the seismic blind deconvolution, and discussed the perspective of applying ICA to seismic blind deconvolution with two possible solutions. The relationship of PC A, ICA and wavelet transform is claimed. It is proved that reconstruction of wavelet prototype functions is Lie group representation. By the way, over-sampled wavelet transform is proposed to enhance the seismic data resolution, which is validated by numerical examples. The key of pre-stack depth migration is the regularization of pre-stack seismic data. As a main procedure, seismic interpolation and missing data reconstruction are necessary. Firstly, I review the seismic imaging methods in order to argue the critical effect of regularization. By review of the seismic interpolation algorithms, I acclaim that de-alias uneven data reconstruction is still a challenge. The fundamental of seismic reconstruction is discussed firstly. Then sparseness constraint on least square inversion and preconditioned conjugate gradient solver are studied and implemented. Choosing constraint item with Cauchy distribution, I programmed PCG algorithm and implement sparse seismic deconvolution, high resolution Radon Transformation by PCG, which is prepared for seismic data reconstruction. About seismic interpolation, dealias even data interpolation and uneven data reconstruction are very good respectively, however they can not be combined each other. In this paper, a novel Fourier transform based method and a algorithm have been proposed, which could reconstruct both uneven and alias seismic data. I formulated band-limited data reconstruction as minimum norm least squares inversion problem where an adaptive DFT-weighted norm regularization term is used. The inverse problem is solved by pre-conditional conjugate gradient method, which makes the solutions stable and convergent quickly. Based on the assumption that seismic data are consisted of finite linear events, from sampling theorem, alias events can be attenuated via LS weight predicted linearly from low frequency. Three application issues are discussed on even gap trace interpolation, uneven gap filling, high frequency trace reconstruction from low frequency data trace constrained by few high frequency traces. Both synthetic and real data numerical examples show the proposed method is valid, efficient and applicable. The research is valuable to seismic data regularization and cross well seismic. To meet 3D shot profile depth migration request for data, schemes must be taken to make the data even and fitting the velocity dataset. The methods of this paper are used to interpolate and extrapolate the shot gathers instead of simply embedding zero traces. So, the aperture of migration is enlarged and the migration effect is improved. The results show the effectiveness and the practicability.

甘肃西峰晚第三纪红粘土地层中的蜗牛化石记录及其古环境意义

In this study, 260 mollusk fossil samples from a Red Clay sequence at Xifeng, Gansu province, in the northern China were analyzed quantitatively. 12 fossil species and four fossil zones have been identified. Three main ecological groups were determined based on ecological requirement of each mollusk taxon. According to fossil composition and succession of three ecological groups, the author discussed the origin and sedimentary environment of the red clay deposits, and the process of ecological environmental changes as well as the variations of the East Asia monsoons during 6.2-2.4 Ma in the Loess Plateau. A preliminary study on periodicity of paleoclimatic changes was also conducted by using spectral analysis method. The main results and conclusions are presented as follows:A continuous land mollusk fossil sequence of 6.2-2.4 Ma from Xifeng Red Clay Formation has been established, which provided a basic data for studying the environmental changes during late Miocene to Pliocene.The study of composition and preservation condition of mollusk fossils reveals a terrestrial in situ ecological population in the Red Clay Formation. All of identifiable mollusk species are composed of terrestrial taxa, which support the view that the Red Clay is an eolian origin, similar to the overlying Quaternary loess deposits.The mollusk record reveals the processes of ecological and environmental changes during 6.2-2.4 Ma in the Loess Plateau. Climatic changes experienced cold and dry from 6.2-5.4 Ma, warm and wet during 5.4-4.5 Ma, mild and moderate from 4.5-3-4 Ma, to rapid cooling and drying after 3.4 Ma. From '5.4- 2.4 Ma, climate was stepwise cooling. The cooling trend is in good agreement with a general1 0global cooling trend during this period, as documented by marine 5 0 records.4. Three remarked ecological shifts took place in mollusk assemblages from 6.2-2.4 Ma, focused on about 5.4, 4.5 and 3.4 Ma. The warming shift around 5.4 Ma was probably related to the rising of the global temperature. The cooling shifts around 4,5 and 3.4 Ma however might be closely linked to the uplift of Tibet Plateau and the development of Northern Hemisphere ice sheet.The succession in mollusk ecological groups also recorded the variability of the East Asian winter and summer monsoon. The winter monsoon dominated two periods from 6.2-5.4 Ma and from 3.4-2.4 Ma, while the summer monsoon was strong during 5.4-4.5 Ma. The variations in winter and summer monsoons were in phase during 4.5-3.4 Ma. Monsoon regimes changed with the duration about 1 Ma, which roughly corresponds to the cycle driven by tectonic activity on the time scales of ICP-IO7 years. In addition, mollusk fossils recorded the large amplitude and high frequency fluctuations overlapped on 105-107 years climate cycle.The maximum entropy spectral analysis and filter-band analysis of total mollusk individuals and three typical ecological groups suggest that the climate changes controlled mainly by solar insolation had periods about 70 ka and 40 ka on the time scales of 105 during late Miocene-Pliocene. Climatic periodicity intensified from 4.0 Ma, which reflected strengthened forcing by high latitude ice volume.

滑坡和泥石流致灾条件叠合技术及风险分析-以川藏公路然乌至鲁朗段为例

As one part of national road No. 318, Sichuan-Tibet (Chengdu-Lasha) Highway is one of traffic life lines connecting Tibet municipality to the inland, which is very important to the economic development of Tibet. In addition, it is still an important national defence routeway, with extremely important strategic position on maintaining the stability and solidarity of Tibet municipality and consolidating national defence. Particular geological condition, terrain and landform condition and hydrometeorological condition induce large-scale debris flows and landslides (including landslips) and the like geological hazards frequently occur along the highway. High frequency geological hazards not only result in high casualties and a great property loss, but also block traffic at every turn, obstructing the Sichuan-Tibet highway seriously. On the basis of considerable engineering geological investigation and analysis to the relative studying achievements of predecessors, it is found that one of the dominating reason incurring landslides or debris flows again and again in a place is that abundant loose materials are accumulated in valleys and slopes along the highway. Taking landslides' and debris flows along Ranwu-Lulang section of Sichuan-Tibet highway as studying objects, the sources and cause of formation of loose accumulation materials in the studying area are analyzed in detail, the major hazard-inducing conditions, hazard, dynamic risk, prediction of susceptibility degree of landslides and debris flows, and the relations between landslides and debris flows and various hazard-inducing conditions are systematically researched in this paper. All of these will provide scientific foundation for the future highway renovating and reducing and preventing geological hazards. For the purpose of quantitatively analyzing landslide and debris flow hazards, the conception of entropy and information entropy are extended, the conception of geological hazard entropy is brought forward, and relevant mathematics model is built. Additionally, a new approach for the dynamic risk analysis of landslide and debris flow is put forward based on the dynamic characteristics of the hazard of hazard-inducings and the vulnerability of hazard-bearings. The formation of landslide and debris flow is a non-linear process, which is synthetically affected by various factors, and whose formation mechanics is extremely complex. Aiming at this question, a muli-factors classifying and overlapping technique is brought forward on the basis of engineering geomechanics meta-synthesis (EGMS) thought and approach, and relevant mathematics model is also built to predict the susceptibility degree of landslide or debris flow. The example analysis result proves the validity of this thought and approach. To studying the problem that whether the formation and space distribution of landslides and debris flows are controlled by one or several hazard-inducing conditions, the theme graphics of landslides and debris flows hazard and various hazard-inducing conditions are overlapped to determine the relationship between hazard and hazard-inducing conditions. On this basis, the semi-quantitative engineering zonation of the studying area is carried out. In addition, the overlapping analysis method of the hazard-indue ing conditions of landslides and debris flows based on "digital graphics system" is advanced to orderly organize and effectively manage the spatial and attributive data of hazard and hazard-inducing conditions theme graphics, and to realize the effectively combination of graphics, images and figures.

Heat capacity enhancement and thermodynamic properties of nanostructured amorphous SiO2

The heat capacity of nanostructured amorphous SiO2 (na-SiO2) has been measured by adiabatic calorimetric method over the temperature range 9-354 K. TG and differential scanning calorimeter (DSC) were also employed to determine the thermal stability. Glass transition temperature (T-g) for the two same grain sizes with different specific surface of naSiO(2) samples and one coarse-grained amorphous SiO2 (ca-SiO2) sample were determined to be 1377, 1397 and 1320 K, respectively. The low temperature experimental results show that there are significant heat capacity (C-P) enhancements among na-SiO2 samples and ca-SiO2. Entropy, enthalpy, Gibbs free energy and Debye temperature (theta (D)) were obtained based on the low temperature heat capacity measurement of na-SiO2. The Cp enhancements of na-SiO2 were discussed in terms of configurational and vibrational entropy. (C) 2001 Elsevier Science B.V. All rights reserved.

Calorimetric study of Wood alloy

The heat capacities of Wood alloy have been measured with an automatic adiabatic calorimeter over the temperature range of 80 similar to 360 K. The thermodynamic data of solid-liquid phase transition have been obtained from the heat capacity measurements. The melting temperature, enthalpy and entropy of fusion of the substance are 345.662 K, 18.47 J.g(-1) and 0.05343 J.g(-1).K-1, respectively. The necessary thermal data are provided for the low temperature thermodynamic study of the alloy.

Chiral separation of enantiomers of amino acid derivatives by high-performance liquid chromatography on a norvancomycin-bonded chiral stationary phase

A novel norvancomycin-bonded chiral stationary phase (NVC-CSP) was synthesized by using the chiral selector of norvancomycin. The chiral separation of enantiomers of several dansyl-amino acids by high-performance liquid chromatography (HPLC) in the reversed-phase mode is described. The effects of some parameters, such as organic modifier concentration, column temperature, pH and flow rate of the mobile phase, on the retention and enantioselectivity were investigated. The study showed that ionic, as well as hydrophobic interactions were engaged between the analyte and macrocycle in this chromatographic system. Increasing pH of buffers usually improved the chiral resolution for dansyl-alpha-amino-n-butyric acid (Dns-But), dansyl-methionine (Dns-Met) and dansyl-threonine (Dns-Thr), but not for dansyl-glutamic acid (Dns-Glu) which contains two carboxylic groups in its molecular structure. The natural logarithms of selectivity factors (In alpha) of all the investigated compounds depended linearly on the reciprocal of temperature (1/T), most processes of enantioseparation were controlled enthalpically. Interestingly, the process of enantioseparation for dansyl-threonine was enthalpy-controlled at pH of 3.5, while at pH of 7.0, it was entropy-controlled according to thermodynamic parameters Delta(R,S)DeltaHdegrees and Delta(R,S)DeltaSdegrees afforded by Van't Hoff plots. In order to get baseline separation for all the solutes researched, norvancomycin was also used as a chiral mobile phase additive. In combination with the NVC-CSP remarkable increases in enanselectivity were observed for all the compounds, as the result of a "synergistic" effect. (C) 2003 Elsevier B.V. All rights reserved.

Heat capacity and thermodynamic properties of N-(2-cyanoethyl) aniline (C9H10N2)

The low temperature heat capacities of N-(2-cyanoethyl)aniline were measured with an automated adiabatic calorimeter over the temperature range from 83 to 353 K. The temperature corresponding to the maximum value of the apparent heat capacity in the fusion interval, molar enthalpy and entropy of fusion of this compound were determined to be 323.33 +/- 0.13 K, 19.4 +/- 0.1 kJ mol(-1) and 60.1 +/- 0.1 J K-1 mol(-1), respectively. Using the fractional melting technique, the purity of the sample was determined to be 99.0 mol% and the melting temperature for the tested sample and the absolutely pure compound were determined to be 323.50 and 323.99 K, respectively. A solid-to-solid phase transition occurred at 310.63 +/- 0.15 K. The molar enthalpy and molar entropy of the transition were determined to be 980 +/- 5 J mol(-1) and 3.16 +/- 0.02 J K-1 mol(-1), respectively. The thermodynamic functions of the compound [H-T - H-298.15] and [S-T - S-298.(15)] were calculated based on the heat capacity measurements in the temperature range of 83-353 K with an interval of 5 K. (c) 2004 Elsevier B.V. All rights reserved.

Low temperature heat capacity of (S)-ibuprofen

Molar heat capacities of ( S)-ibuprofen were precisely measured with a small sample precision automated adiabatic calorimeter over the temperature range from 80 to 370 K. Experimental heat capacities were fitted into a polynomial equation of heat capacities ( C-p,C- m) with reduced temperature ( X), [ X = f(T)]. The polynomial equations for ( S)-ibuprofen were C-p,C- m(s) = - 39.483 X-4 - 66. 649 X-3 + 95. 196 X-2 + 210. 84 X + 172. 98 in solid state and C-p,C- m(L) = 7. 191X(3) + 4. 2774 X-2 + 56. 365 X + 498. 5 in liquid state. The thermodynamic functions relative to the reference temperature of 298. 15 K, H-T - H-298.15 and S-T - S-298.15, were derived for the( S)-ibuprofen. A fusion transition at T-m = (324. 15 +/- 0. 02) K was found from the C-p - T curve. The molar enthalpy and entropy of the fusion transition were determined to be (18. 05 +/- 0. 31) kJ.mol(-1) and (55. 71 +/- 0. 95) J.mol(-1).K-1, respectively. The purity of the ( S)-ibuprofen was determined to be 99. 44% on the basis of the heat capacity measurement. Finally, the heat capacities of ( S)-ibuprofen and racemic ibuprofen were compared.