144 resultados para Modified Direct Analysis Method
Resumo:
The CSAMT method is playing an important role in the exploration of geothermal and the pre-exploration in tunnel construction project recently. In order to instruct the interpretation technique for the field data, the forward method from ID to 3D and inversion method in ID and 2D are developed in this paper for the artificial source magnetotelluric in frequency domain. In general, the artificial source data are inverted only after the near field is corrected on the basis of the assumption of half-homogeneous space; however, this method is not suitable for the complex structure because the assumption is not valid any more. Recently the new idea about inversion scheme without near field correction is published in order to avoid the near field correction error. We try to discuss different inversion scheme in ID and 2D using the data without near field correction.The numerical integration method is used to do the forward modeling in ID CSAMT method o The infinite line source is used in the 2D finite-element forward modeling, where the near-field effect is occurred as in the CSAMT method because of using artificial source. The pseudo-delta function is used to modeling the source distribution, which reduces the singularity when solving the finite-element equations. The effect on the exploration area is discussed when anomalous body exists under the source or between the source and exploration area; A series of digital test show the 2D finite element method are correct, the results of modeling has important significant for CSAMT data interpretation. For 3D finite-element forward modeling, the finite-element equation is derived by Galerkin method and the divergence condition is add forcedly to the forward equation, the forward modeling result of the half homogeneous space model is correct.The new inversion idea without near field correction is followed to develop new inversion methods in ID and 2D in the paper. All of the inversion schemes use the data without near field correction, which avoid introducing errors caused by near field correction. The modified grid parameter method and the layer-by-layer inversion method are joined in the ID inversion scheme. The RRI method with artificial source are developed and finite-element inversion method are used in 2D inversion scheme. The inversion results using digital data and the field data are accordant to the model and the known geology data separately, which means the inversion without near field correction is accessible. The feasibility to invert the data only in exploration area is discussed when the anomalous body exists between the source and the exploration area.
Resumo:
In order to realize fast development of the national economy in a healthy way and coordinate progress with whole society, the country has implemented the strategy of development of the western region. An important action of finishing this strategic task is to accelerate the highway construction in the western region, join the western region and places along the coast, the river, the border with goods and materials, technology, and personnel interchanges, and then drive development of the local economy.The western region was influenced by the Himalaya Tectonization in Cenozoic, and the crust rose and became the plateau. In the course of rising, rivers cut down sharply to form a lot of high mountains and gorges.Because of topography and geomorphology, bridges in the traffic construction in the alpine gorge area are needed. Rivers have characteristics of large flow, fast velocity and high and steep river valley, so building a pier in the river is not only very difficult, but also making the cost increase. At the same time, the impact that the pier is corroded and the bridge base that is drawn to be empty by flow are apt to cause destruction of the pier. For those reasons, suspending bridge and cable-stay bridge are usually adopted with the single and large span. For the large span bridge, the pier foundation could receive ten thousand and more vertical strength, bending moment and near kiloton horizontal thrust.Because bank slope in the alpine gorge district is cut deeply and unsettled big, natural stability is worse under endogenic and exogenic force. When bank slope bears heavy vertical strength, bending moment and horizontal thrust facing the river, it will inevitably make the balance state of rock and soil mass change, bridge bank slope deform, and even destroyed. So the key problem at the time of the large span's bridge construction in the alpine gorge area is how to make it stable.So based on the spot investigation, the Engineering Geology Analysis Method is very important to grasp the bank slope stability. It can provide the bank slope stability macroscopic ally and qualitatively, and reference to the indoor calculation. The Engineering Geology Analysis Method is that by way of analyzing and investigating terms of bank slope instability, stability development trend, the ancient rock slide and devolution in the site, stability comprehensive evaluation primarily, current and future stability of bank slope is gotten, realizing the intention to serving the concrete engineering.After the Engineering Geology Analysis Method is applied to project instances of BeiPan River Bridge and BaLin River Bridge, results are accord with bank slope actual conditions, which proves sites are suited to building bridges from site stability.we often meet bank slope stability issues in the traffic construction in the alpine gorge areao Before the evaluation of the bank slope stability, the engineering geological condition is investigated first. After that, the next exploration target and geology measures are decided. So, the Engineering Geology Analysis Method that the investigation of the engineering geological condition is the main content is quite important in practice. The other evaluations of the bank slope stability are based on it. Because foundation receives very heavy load, for the big span's bridge in the alpine gorge area, a long pile of the large diameter (D^0.8m) is usually selected. In order to reflect rock mass's deformation properties under rock-socketed pile function, the author has used the FLAG30 software for rock and soil mass and done many numerical simulations. By them, the author launches the further investigation on deformation properties of bank slope under different slope angle, pile length, diameter, elastic modulus, load, bank slope's structure, etc. Some conclusion meaningful to the design and produce are obtained.
Resumo:
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.
Resumo:
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.
Resumo:
In exploration seismology, the geologic target of oil and gas reservoir in complex medium request the high accuracy image of the structure and lithology of the medium. So the study of the prestack image and the elastic inversion of seismic wave in the complex medium come to the leading edge. The seismic response measured at the surface carries two fundamental pieces of information: the propagation effects of the medium and the reflections from the different layer boundaries in the medium. The propagation represent the low-wavenumber component of the medium, it is so-called the trend or macro layering, whereas the reflections represent the high-wavenumber component of the medium, it is called the detailed or fine layering. The result of migration velocity analysis is the resolution of the low-wavenumber component of the medium, but the prestack elastic inversion provided the resolution of the high-wavvenumber component the medium. In the dissertation, the two aspects about the migration velocity estimation and the elastic inversion have been studied.Firstly, any migration velocity analysis methods must include two basic elements: the criterion that tell us how to know whether the model parameters are correct and the updating that tell us how to update the model parameters when they are incorrect, which are effected on the properties and efficiency of the velocity estimation method. In the dissertation, a migration velocity analysis method based on the CFP technology has been presented in which the strategy of the top-down layer stripping approach are adapted to avoid the difficult of the selecting reduce .The proposed method has a advantage that the travel time errors obtained from the DTS panel are defined directly in time which is the difference with the method based on common image gather in which the residual curvature measured in depth should be converted to travel time errors.In the proposed migration velocity analysis method, the four aspects have been improved as follow:? The new parameterization of velocity model is provided in which the boundaries of layers are interpolated with the cubic spline of the control location and the velocity with a layer may change along with lateral position but the value is calculated as a segmented linear function of the velocity of the lateral control points. The proposed parameterization is suitable to updating procedure.? The analytical formulas to represent the travel time errors and the model parameters updates in the t-p domain are derived under local lateral homogeneous. The velocity estimations are iteratively computed as parametric inversion. The zero differential time shift in the DTS panel for each layer show the convergence of the velocity estimation.? The method of building initial model using the priori information is provided to improve the efficiency of velocity analysis. In the proposed method, Picking interesting events in the stacked section to define the boundaries of the layers and the results of conventional velocity analysis are used to define the velocity value of the layers? An interactive integrate software environment with the migration velocity analysis and prestack migration is built.The proposed method is firstly used to the synthetic data. The results of velocity estimation show both properties and efficiency of the velocity estimation are very good.The proposed method is also used to the field data which is the marine data set. In this example, the prestack and poststack depth migration of the data are completed using the different velocity models built with different method. The comparison between them shows that the model from the proposed method is better and improves obviously the quality of migration.In terms of the theoretical method of expressing a multi-variable function by products of single-variable functions which is suggested by Song Jian (2001), the separable expression of one-way wave operator has been studied. A optimization approximation with separable expression of the one-way wave operator is presented which easily deal with the lateral change of velocity in space and wave number domain respectively and has good approach accuracy. A new prestack depth migration algorithm based on the optimization approximation separable expression is developed and used to testing the results of velocity estimation.Secondly, according to the theory of the seismic wave reflection and transmission, the change of the amplitude via the incident angle is related to the elasticity of medium in the subsurface two-side. In the conventional inversion with poststack datum, only the information of the reflection operator at the zero incident angles can be used. If the more robust resolutions are requested, the amplitudes of all incident angles should be used.A natural separable expression of the reflection/transmission operator is represented, which is the sum of the products of two group functions. One group function vary with phase space whereas other group function is related to elastic parameters of the medium and geological structure.By employing the natural separable expression of the reflection/transmission operator, the method of seismic wave modeling with the one-way wave equation is developed to model the primary reflected waves, it is adapt to a certain extent heterogeneous media and confirms the accuracy of AVA of the reflections when the incident angle is less than 45'. The computational efficiency of the scheme is greatly high.The natural separable expression of the reflection/transmission operator is also used to construct prestack elastic inversion algorithm. Being different from the AVO analysis and inversion in which the angle gathers formed during the prstack migration are used, the proposed algorithm construct a linear equations during the prestack migration by the separable expression of the reflection/transmission operator. The unknowns of the linear equations are related to the elasticity of the medium, so the resolutions of them provided the elastic information of the medium.The proposed method of inversion is the same as AVO inversion in , the difference between them is only the method processing the amplitude via the incident angle and computational domain.
Resumo:
Fluvial Sedimentation of alluvial facies prevailed during the Late Jrassic in the Minhe Basin.On the basis of the study of sedimentary facies of the Upper Jurassic series.this paper focuses on the river types suing the "Architecture Element" analysis method proposed by Miall,and calculated all the quantitative parameters to reflect the characteristics of the stream channel geometry and hydrodynamic conditions of paleo-rivers with the equations of ethrideg,schumm et al.Finally,we discussed the characteristics of environmental evolution of palsorivers on the quantitative basis.Our conclusion indicates that the evolution of paleo-rivers during the Late Jurassic,from early to late,shows such a tendency as alluvial fan river→ braid river→alluvial fan river→mid-sinuoisty river→ high-sinuosity river.
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生物有机酸是大气对流层中重要的微量挥发性有机碳组分,它广泛存在于对流层大气中,对气候、环境、生态系统以及人类健康产生了重要影响。探索有机酸碳同位素(δ13C值)的分析测试方法,能够为大气有机酸生物地球化学循环研究开辟一片新的天地,从而使该领域研究向前推进一步。本研究初步建立了以甲酸、乙酸为代表的大气中低分子有机酸的碳同位素测试分析方法,为研究“已知有机酸来源中,不同来源对大气有机酸含量的贡献大小问题”、“人类污染对大气中有机酸的贡献比例问题”以及“是否存在尚未认知的有机酸来源问题”等奠定了方法学基础。 研究工作围绕如下五个方面内容而展开:首先是回顾和总结大气中低分子有机酸的研究沿革,详细摘录了国内外不同站点不同形式的大气样品中有机酸含量水平及其分布情况;其次是回顾和总结了大气中低分子有机酸的含量分析方法,并从中获取适宜于气相色谱/燃烧炉/同位素比值质谱(GC/C/IRMS)接口的样品富集、分离技术;第三是对水溶液中低分子有机酸的固相微萃取研究;第四是对实际大气样品中微量甲酸、乙酸的固相微萃取研究及其碳同位素分析结果的初步分析;第五是对其它天然产物或人为活动排放源所释放的甲酸、乙酸碳同位素进行研究。研究内容的重点是:应用目前对水溶液中痕量有机酸而言最恰当的针阱捕集固相微萃取技术建立有机酸分子碳同位素组成分析方法。在方法建立过程中主要获得了如下成果: 1. 建立了以甲酸、乙酸为代表的液态挥发性有机化合物标准样品的碳同位素组成分析测试方法。 法兰静密封技术与石英管的连接技术可以有效地获得较高真空度的石英管,这使得向低CO2污染的石英管内无损耗地注入挥发性有机物的标准样品成为可能。进一步使用炬枪密闭-石英管燃烧法制备挥发性有机化合物标准同位素样品,可有效避免制备过程中因挥发所导致的同位素分馏和环境CO2对测定值的影响。以市售高纯度的甲酸、乙酸为标准同位素样品,重复制备它们的同位素分析样各5次,并在Finnigan MAT-252气体同位素比值质谱仪上测定其δ13C值。结果显示此法具有极高的重现性,所测δ13C值相对标准偏差仅为0.07%(甲酸,n=5)、0.04%(乙酸,n=5)。与之对比,另一套同位素测定系统GC/C/IRMS对同一标准物质的同位素测定结果并无显著差别,但在精度上却明显不及前者。由于避免了样品制备过程中可能因挥发而导致的同位素分馏以及可能因环境中CO2造成污染等问题,使得该方法可推广应用于其它挥发性有机化合物标准的δ13C标定,为准确测定实际样品中对应挥发性有机化合物δ13C值的准确测定提供基础条件,也为同类物质标准的碳同位素测定提供了准确、廉价、方便的分析手段。 2. 确立了甲酸、乙酸在线分离的气相色谱条件以及同位素分析所需的同位素比值质谱条件。 为了能对非衍生化处理的甲酸、乙酸进行有效分离,我们选取了低吸附性、高样品容量,可直接分析未衍生化游离酸的Stabilwax-DA色谱柱作为分离甲酸、乙酸的分析柱。气相色谱分离过程中He载气均处于恒流模式,进样口施行不分流进样,并进样口温度设置为200℃,采用两阶段程序升温,在此条件下乙酸、甲酸的出峰时间先后相隔了0.79分钟,且多次测定甲、乙酸出峰时间的相对标准偏差不大于0.05分钟,据此可认为甲、乙酸获得了良好的分离。 气相色谱分离出的甲酸、乙酸通过串联接口与燃烧炉 (串联接口与燃烧炉都是加热装置,温度分别设置成350 C和 850C)相接,随后有机物在燃烧炉中被高温焚烧转变为CO2和H2O,再经Nafion半透膜祛除H2O,从而获取纯化干燥的CO2以适宜于同位素比值质谱分析。 3. 确立了水相中甲酸、乙酸的微萃取条件,设计制作了与萃取工作配套固相微萃取装置。 NeedlEx针阱捕集的固相微萃取技术可解决水溶液中低分子有机酸的分离萃取问题,并能与气相色谱接口的兼容,还有集采样、富集、保存、分析为一体的优点。因此探索利用脂肪酸型NeedlEx完成对水溶液相中有机酸的萃取是本文研究的关键所在。为了提高分析效率,降低环境污染,我们设计了一整套吹扫-捕集的动态固相微萃取装置,并对甲酸、乙酸的水溶液实施了萃取研究。 由于实验装置是在吹扫捕集原理的基础上建立起来的,因此随着吹扫捕集气体体积的增加有机酸在萃取针上的对富集量也呈现出一定增长趋势,尤其是在最初的几次循环中,有机酸在萃取针中的总量得到迅速的增加,在萃取气体体积达到400mL后,萃取针中的有机酸含量增加趋于缓慢。为了获得更多物质量的有机酸,实验中我们分别尝试了1000和2000mL的气体吹扫体积,分别对有机酸在色谱上的响应值以及同位素分析结果的统计显示这两种萃取体积并无显著差异,为兼顾工作量我们拟定1000mL吹扫气体体积作为实验条。 由于离子态的有机酸具极强的亲水性,因而很难挥发至顶空或吹扫气体中,只有自由的分子态有机酸方可被萃取针中疏水的固定相所富集。为使的解离反应方向朝着有利于分子态有机酸形成方向发展,我们评估了不同酸化条件对萃取效果的影响。实验中我们普遍采用了500μL 4mol/L的磷酸溶液对样品进行了酸化,结果表明,酸化对提高待测物质的分析量十分有利,以10μg/mL的甲酸、乙酸标准溶液为例,酸化后甲酸萃取率提高了30.12%,乙酸的萃取效率也提高了14.46%。酸化、不酸化处理以及不同浓度有机酸溶液所测定的甲、乙酸碳同位素值在总体上不具备显著性的差异。但是,由于有机酸碳同位素测定精度与待测物物质量具有一定正相关关系,因此酸化后样品中有机酸同位素的分析精度要优于未经酸化样品的同位素的分析精度。 温度的增加可以适量地提高部分有机酸的萃取效率,但温度增加导致水汽进入萃取针,中从阻碍了有机酸的有效萃取,因此本文建议在25℃室温的下进行萃取。此外,在传统的固相微萃取过程,搅动样品溶液常常是作为缩短萃取时间,提高的萃取效率的重要措施。原则上搅拌速度越快越好,但为了不使溅起水花影响到萃取针头,因而选择2000r/min搅拌速度比较适宜。 基于上述实验条件,本文考察了浓度为10~300μg/mL的甲酸、乙酸标准溶液的色谱响应值及其同位素分析结果。结果显示对不低于浓度为10μg/mL标准溶液,其中甲酸、乙酸的δ13C值都可被检测出。只不过浓度过低则响应值信号弱,不能准确计算出各质荷比信号峰面积是低浓度条件下同位素测不准的主要原因。要想使得甲、乙酸同位素测定值的相对标准偏差控制在1以内,则对应有机酸浓度则需达到85μg/mL以上。 4. 克服了实际水相样品中有机酸浓度低,不能直接对其实施NeedlEx萃取的难题,初步实现了对降水中甲酸、乙酸的碳同位素分析。 除了某些有机酸含量水平较高的降雨可以直接运用动态针阱捕集固相微萃取与GC/C/IRMS联用技术直接进行甲酸、乙酸碳同位素的分析外,普通含量水平的有机酸碳同位素测定尚具有一定的难度。研究中我们使用了阴离子交换型固相萃取小柱LC-SAX(规格:500mg/3mL;交换容量:0.2meq/g)对1L浓度为50~2000μg/L甲酸、乙酸标准混合溶液进行了萃取,并对所属浓度条件下δ13C测定值与理论值之间的差异性进行了T检验统计分析,结果表明绝大多数情况(200μg/L乙酸同位素测定值除外)下甲、乙酸的相伴概率分别伴概率大于了显著性水平0.05,表现出有机酸碳同位素测定的均值与离线法测定的甲酸同位素理论值无显著差异。 然而,降水中普遍具有有机酸含量低,其它阴离子含量高,组分复杂特点,严重影响阴离子交换型萃取小柱对有机酸的萃取。为此我们先用离子色谱对降水中阴离子组成及其含量进行分析,了解降水中主要的阴离子构成及其含量,再根据所测定结果再安排对应交换容量萃取小柱实施萃取,而后再进行针阱捕集的萃取及其碳同位素分析。 5. 对以甲酸、乙酸为代表的大气中低分子有机酸碳同位素分析结果的初步研究。 以贵阳为代表的西南城市地区大气中有机酸浓度较高,这为使用本方法研究该地区有机酸的碳同位素分析创造了有利条件。经离子色谱测定,2008年8月下旬至2008年10月中旬贵阳地区6次降水中甲、乙酸浓度范围分别为5.75~22.43μmol/L和5.43~13.09μmol/L。与之对应,六次降水中甲酸δ13C值的范围为-25.72‰至-29.08‰之间,乙酸δ13C值的最大值则为-26.23‰,最小值则为-30.40‰。6次降水中甲酸、乙酸的δ13C值将它们的来源指向了直接或间接的陆源特征。结合离子色谱对降水中甲酸、乙酸浓度分析,利用亨利系数判定法可知,六次降水中间接来源是大气中低分子有机酸的主要来源,通过δ13C值的初步判断,可以看出这些二次来源应该主要由生物质燃烧,C3植物以及人类活动向大气释放的不饱和有机物经二次氧化而形成。 以往甲酸、乙酸同源的依据皆以降水中甲、乙酸浓度具有显著线性相关做为判断指标,本研究中6次降中的甲酸、乙酸浓度亦然呈现出良好的相关性(R2=0.87)而降水中甲、乙酸具有相似的δ13C值,这充分说明降水中甲、乙酸的同源特征。 针阱捕集萃取方式还适宜于对大气中自由有机酸的直接富集。利用这一特性,我们分别对贵阳市市郊森林公园、城市居民区以及交通要塞等三个不同地方大气中的自由有机酸进行了同位素分析,结果发现贵阳市大气中乙酸δ13C值介于-31.03‰至-26.37‰之间,乙酸δ13C值的总体均值等于-28.74‰,与之对应,甲酸的δ13C值范围为-29.42‰至-22.97‰,均值为-27.12‰。贵阳市大气中自由甲酸、乙酸的同位素值与降水中的甲、乙酸同位素值具有类似的变化范围,这表明大气气相中自由有机酸与降水中的甲、乙酸具有大致相同的来源构成。 我们还利用此法对汽车尾气以及蚁酸蚁所释放的甲酸、乙酸δ13C值进行了分析,其中汽车尾气中所含甲酸δ13C值等于-23.25±1.25‰,乙酸δ13C值为-24.55±0.85‰,而蚁酸蚁所释放的甲酸δ13C值则为-22.43±0.43‰。由于汽车尾气以及乙酸蚁释放有机酸的δ13C值要低于大气样品对应有机酸的δ13C值,据此认为汽车尾气和蚁酸蚁不是大气有机酸的主要来源。 6. 有机酸碳同位素分析技术在检验食品参假行为时的扩展应用研究。 由于C3和C4循环会导致植物及其产品的δ13C值不同,因此碳同位素技术在食品控制方面发挥了特别作用,能够解决一些常规分析解决不了的问题。经分析发现,食醋中醋酸的δ13C值与其原材料密切相关,如以麦麸、大米为原材料所生食醋醋酸δ13C值在-27‰左右。而以高粱、大麦、黄豆为生产原料的食醋醋酸δ13C值在-19‰左右,明显高于了以大米、麦麸等为原料所生产的食醋醋酸δ13C值。此外,单纯以大米发酵生产的食醋醋酸δ13C值为-29‰左右。食醋中醋酸δ13C值与生产工艺、原材料高度相关的特征为质检部门更好的识别食醋参假行为提供了良好的解决办法。
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The research objectives were to investigate the psychological structure of employees' organizational commitments(OCs), and its antecedents, and to examine the relative effects of employees' OCs to their performances. In order to deeply uncover the nature of OCs, some standard methods, such as in-depth interview, focus-group, semi-open questionnaire, standard questionnaire etc., were employed. In data analysis, not only some common statistical methods, such as multivariate analysis of variance, cross-table analysis, factor analysis, but also some forefront ones, such as confirmatory factor analysis and path analysis of SEM, were used. The paper covers six chapters: 1) In the first chapter, Firstly some previous empirical studies, which examined structures, antecedents, correlates, and/or consequences of organizational commitment in China and Western countries, were summarized. This summary covers most of the respectable researchers' works of this field, such as H.S.Becker, B.Buchanan, L.W.Porter, G. Ritzer, H.M.Trice, J.A.Alutto, L.G.Hrebiniak, R.T.Mowday, J.P.Meyer, N.J.Allen, G.W.McGee, R.C.Ford, R.Eisenberger, etc. Then three theoretical hypothesis were put forward as following: ① In China, OCs should be multidimensional psychological structures, which means there should exist more than one type of OCs; ② There should be some different antecedents to different OCs; ③ Employees with different types of OC should perform differently in their works. Finally the theoretical and practical significance were discussed. 2) In the second chapter, great efforts were made to investigate the OC types. Firstly, in-depth interview with managers and employees, semi-open questionnaire, and some other methods were used in the pilot research to gather much qualitative material. Then OC questionnaire was designed to get quantitative data in about 20 enterprises, including state-owned, collective-owned, wholly foreign-funded, and joint-ventures. During revising of this questionnaire, there were about 5000 samples surveyed. after factor analysis, the data shows that there should be 5 types of OCs in China, which were respectively named as Affective Commitment, Normative commitment, Ideal Commitment, Economic Commitment, Choice Commitment. Thirdly, confirmatory factor analysis method was used to successfully confirm this 5-factor model. Finally, Cronbach a and test-retest correlate indicate that this questionnaire is reliable. Since factor analysis result has show its construct validity, a simple criterion-related validity research was conducted. 3) In order to investigate the correlation between different OC and employee performance and different antecedents of OC, 5 other questionnaires, such as Employee Satisfaction Questionnaire, Perceived Organizational Support Questionnaire, Social Exchange Questionnaire, Altruism Scale, and Leader Confidence Scale were revised in the third chapter. 4)In the fourth chapter, a lot of correlates, cross-table analysis were conducted to show the correlation between different OCs and 10 performances, which indicate employees with different OCs will show different performance in 10 variables, such as altruism, etc. 5) In the fifth chapter, correlate analysis, multivariate of analysis, and path analysis of SEM were used to investigate the antecedents of OC. A satisfactory model showing the correlation between OC and their antecedents was confirmed. 6) In the last chapter, all researches about OC, and its limitations were summarized.
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Brand image is the attributes set and the related associations of a brand in consumers mind, and it is the subjective reflections of brands. The paper explored the factors of brand image system and their weight. As the traditional means to evaluate weight coefficients are not perfect, a new method, conjoint analysis, was attempted. The factors of brand image were explored through questionnaire. Sports sneaker, toothpaste, and personal stereo were chosen as product sample, and four hundred and twenty university students from Tangshan city and Beijing as subjects(each person evaluated two kinds of products). The first two kinds of products were requisites of students, and sports sneaker belonged to High conspicuous products and toothpaste was low conspicuous product. On the other hand, personal stereo was the sample of development and entertainment products. Several factors of three products brand were taken out with factor analysis. In order to explore the weight of the brand image factors, a contrast of factor contribution ratio method, holistic quartation method and conjoint analysis is made here. Twenty university students evaluated the weight of the image factors of three kinds of brand with holistic quartation method, then they gave the weight of personal stereo with conjoint analysis method. Product function, advertising and propaganda, symbolic meaning, market orientation, brand appetency, consuming experience are the factors of sports sneaker brand image. Product function, advertising and propaganda, market orientation, product grade, corporation image are the factors of toothpaste brand image. Corporation image and product function, advertising and propaganda, consuming experience, symbolic meaning, price and function ratio are the factors of personal stereo brand image. So the hypothesis was proved that brand image is an ordinal and organical system, "ordinal" means the weight of factors are different, "organical" means that brand image can be deposed into several factors and the factors belonged to function components and meaning components (function components are the factors about physical characteristics and function, which are called "hard factors"); meaning factors are those that can show the personality、value and lifestyle of consumers, which are called "soft factors". The research also gave evidence of the hypothesis below: the factor structures of brand image of different product category have commonness and individuality; the function components of low conspicuous products are more important than the high conspicuous products. The exploration of conjoint analysis is what the paper seeks to be some creative in some degree.