Suburbs began to appear in the 18th century as the privilege of wealthy people. But due to various factors, the United States became the first suburban society within two centuries. The U.S. Census confirmed this fact in 2000 when it reported that over 50 percent of Americans lived in the suburbs. While suburbia defines great swaths of American landscape, its impact has been much more physical and geographic. Suburbanization is a process that has shaped crucial historical developments in America. The rise of suburbs was inextricably linked to the changes in Americanand cultural life. It symbolizes the fullest embodiment of contemporary culture and manifests such fundamental characteristics of American society as mass consumption, a reliance on the automobile and family value. So, in order to understand suburbanization of America, it is of great importance to look into the history of suburbanization from the and cultural perspective.The topic of suburbanization is an important part of urbanization, which can be interpreted from many perspectives. American historians and sociologists were pioneers in the study of the historical and aspects of American suburbanization, followed by economists, geographers, and architects. In recent years, with the integration of different disciplines, the study of suburbs in America has become a heated topic for research. Although much light has been shed on this field, studies on this topic are far from systematic and comprehensive. Moreover, most academic papers focused their attention on the consequences brought about by suburbanization, with only a few on its creation. Different from other works, this thesis endeavors to analyze the factors that drove the suburbanization in America by adopting interdisciplinary approach—the theories and methods that have been used in sociology, geography, and demography.The factors contributing to the suburbanization of America were multitude and diversified. In this thesis, three major factors, namely, technological advancement, prosperity and social believes, are discussed and analyzed in details It was exactly spurred by these three key factors that America witnessed the simultaneous decline of the industrial cities and the rise of the suburbs. In the process of disengaging from industrial past, manual work was becoming less valued, commercial buildings replaced factories, and production was surpassed by consumption. The urban landscape receded from view as people abandoned the central cities and small towns for new suburban communities, embraced middle-class lifestyles, and rearranged their daily existence around a status-conscious consumption.More significantly, these various factors influenced and interwove into each other, driving the development of suburbs in different ways. A reinvented America, now anchored in the suburbs, was projected. There, on the peripheries of the older cities, Americans created a unique way of life, one independent of the constraints but not devoid of the opportunities of large cities. This thesis is devoted to analyzing the major factors for the suburbanization of America, arguing that, as a result of suburbanization process, American society started to assume many new characteristics, which, by now, have become part and parcel of modern American life.
Model selection is an extremely important part of the statistical modeling . The traditional methods which generally use stepwise regression with AIC and BIC criteria for the choice of the optimal model exsit some limitaions. Tibshirani, R. (1996) proposed a new model selection method called Lasso which overcome the limitaions. Efron, etc. (2004) proposed that an effective algorithm to solve Lasso. There are also some limitaions in Lasso method.Many scholars put forword the improved Lasso methods, such as:(Fan 2001 )、Adaptive lasso (Zou 2006 and Wang 2007)、 (Zou and Hastie 2005) and (Nicolai Meinshausen 2007).The main job of this paper are following:(1) We give a comprehensive comparative study of Lasso、 、 、 and based on linear model and point out the relationship of them.(2) We study Lasso and related methods of some differences in Logistic regression methods used the real data ,and systemetically introduce the unified approach to Lasso model selection on the basis of generalized linear model.(3) Finally, we point out some problems to further study.
It’s inevitably to effect onbecause of highway construction, especially thecontinuity and integrity of natural were changed and the balance of naturalprotect environment was destroyed. So, it’s necessary to propose some efficient low carbonmeasures and immensely reduce the effect on surroundings in order to harmonize the highwayconstruction with environment protecting, adhere to the road of sustainable development,guide for the subsequent highway construction.By paying attention to the chemical-physical characteristic of flyash, gangue,polystyrene, foam,slag,aeolianite, discussing the feasibility of roadbed materials andapplication in , in addition, in response to the material of protective railings, PP、PE、glass fiber reinforced plastics、PVC guardrail recycle and green, reduce the emission rateof CO2apparently and can be used widely.There is a dominant position on the highway construction and index andecology; thus, the ecological swales which had the advantage of enormous soil erosion,Steady performance and pollution reduction can be used widely relative to masonry.In the end, evaluating the impact of environment, water environment, aerosolenvironment in order to reduce the emission of carbon in the period of construction bydiscussing the of highway construction, it will reduce the impact efficiently. construction as the hotpot of , energy and more and more people payattention to it, and it use new idea, The new material, new methods, new techniques and so onto reduce the emission of carbon. Low carbon design concept is from planning design,construction of the construction of the overall consideration, connecting with the practice, payattention to study design index rationality and low carbon energy saving effect of the mutualrelations, and finally the scientific and reasonable measures, to determine the design scheme.
Huabei plain is relatively shortage of water resource area in china. Tianjin islocated on the lower basin of the Haihe river, due to its special nature geographicalfeature, Tianjin is lack of water resources supply. Agriculture is threatened by floodand lack of water. Tianjin is one of the areas, which are sufficient in water resource,whose average amount per person is 160m3. The problem of the lacking in waterresource is very serious in Tianjin. Since 1980s, the increase shortage of waterresources has seriously restricted by the rapiddevelopment of the world.In order to supply water safety to the city, Tianjin government has established thepolicy that water for cities and towns domestic is priority to water for industry, waterfor industry is priority to water for agriculture.To overcome the problems of lack of water resources and need of developing ofwater-saving agriculture situation, the exploitation of shallow slight salt water andsalt water and reuse of wastewater are new agriculture resource at present and in thefuture in Tianjin. This technique is reusing the slight salt water and salt water of3-5g/L content for irrigation in heavy clay soil, in order to achieve the objective ofthe water saving, high production and low-cost. Research in different clay soil, wellstructure and drilling well technology, enlarge well water quantity supplying,achieve to get high production, reusing salt water for irrigation, and realize theagriculture sustainable development. Establish a guideline for using slight salt water(less than 5g/L content) for farm irrigation. Develop a new technique for slightsaltwater irrigation construction system, shallow well (30m depth) constructiontechnique and well structure.Technique for slight salt-water reusing irrigation overcomes the problem ofshallow clay soil, extending slight salt-water content level of EPA for irrigation.Research indicates, slight salt water can flow into depth salt water in naturecondition;deep salt water can flow into shallow slight salt water by exploitation.Research test proved, the technique for digging well by pumping slurry can protectwall of well, is suitable for exploitation shallow slight salt water.
China’s traditional virtue is the special and unceasing moral theory and ideological concept in China’s traditional culture which occupies the important status in Chinese history and even in the history of the whole human civilization development. It is the fruit of Chinese 5000-years’ civilization history and gives birth to the national spirit with grand、 deep and full contents. As a spiritual force with comprehensive influence and powerful cohesion, the national spirit plays an essential and unreplaceable role in the development of our nation. The promotion and development of Chinese national spirit are beneficial to form the commom ideal and scientific belief of our whole nation, totally implement and fulfill the view of scientific development, fresh the mentle attitude of the whole society and cultivate modem personality with national spirit, to build Xiaokang Society and achieve the prosperity of Chinese nations at length.Jiang Ze-min once said : A nation without its own morel suppots equals to it has no soul which will make it lose cohesive force and life .Whether it has national spirit or not is an important actor to judge the complex national strength of a nation.Complex national strength refers to material force, such asforce、 technical force, etc.but it also include national spirit which is the important part of the national strength.Owing to the traditional virtue and national spirit, China can stand in the world as a giant. We should have not only material culture but also moral culture because a superior nation should has excellent and special culture as its basis.From this point the development of our nation lies in the of national spirit in some extent.The thesis deeply analyses the background of promoting&developing China’s traditional virtue and cultivating the national spiri, mainly states the scientific connotation of China’s traditional virtue and the national spirit, points out the internal and important relationship between them and at length constructively puts forward the practiceable ways of promoting&developing China’s traditional virtue and cultivating the national spirit.
The geometry of classical groups over finite fields is a kind of important algebra and geometry structure.Many mathematicians constructed some graphs using geometry spaces.For example,dual polar graph,symplectic graph,（isotropic） orthogonal graph and so on.In this paper, we further generalize the construction of dual polar graph and（isotropic） orthogonal graph. We construct a graph using all the m-dimensional totally isotropic subspaces in theover finite fields of odd characteristic.We call the graph to be and denote it to be GOm（2v+δ,q）.We use algebraic method to discuss the geometry spaces.Moreover,we get some conclusions about GOm（2v+δ,q）.In this paper,we obtain the valency,diameter and formula of the distance between any two vertices of GOm（2v+δ,q）.When m=2,we discuss the of GO2（2v+δ,q） and show that the of GO2（2v+δ,q） has q+1 connected components which are isomorphic each other.Whenδ=0,v≥3,we prove that each connected component is and get its parameters and diameter.When m=1,GO1（2v+δ,q） is（isotropic） orthogonal graph.When m=v,GOv（2v+δ,q） is dual polar graph.Therefore,GOm（2v+δ,q） is the generalization of（isotropic） orthogonal graph and dual polar graph.
Digitaland are very important in the precondition of remote sensing. Digital means jointing two or more digital images ( maybe these images had been obtained under different Photographic condition) and making them as one picture. Image mosaic has great importance in the application of remote sensing.How to joint images in geometrics is the first problem of mosaic technique. The core issue of Geometric mosaic is image correction. How to avoid the obvious gap in gray or color is the second problem. So, it has important meanings to set up the system of image mosaic and in the later processing of remote sensing.The paper mainly studied on the image mosaic and . On the base of drawing lessons from the research results of predecessors the paper discussed the processing methods of image mosaic, and mainly focused on study the color equalization approach and the problem of smooth transition of images.
Fiber grating is a new kind of all-fiber passive device thatresults from that the refractive index of optical fiber core isperiodicity microperturbation. Because of the excellent propertiessuch as compatible with optical fiber, easy fabrication, littleinsert loss, small volume and low price, fiber gratings have wideapplication in optical fiber communication and sensor field. Thus,since the successful fabrication of first fiber grating, thefabrication and application of fiber gratings is central issue ofinterest all along.Fiber Bragg grating (FBG) is one type of reflection gratingswhose reflective wavelength depends on the product of grating’seffective refractive index and grating’s period, and grating’sreflectivity and bandwidth depend on the change in refractive indexalong grating and grating’s length. Then, designing grating’speriod and modulating the change in index can fabricate Bragg fibergrating with different reflective wavelength and reflectivity;inaddition, Bragg fiber grating has especially sensitivity to thetemperature and strain. It is these unique properties that makeBragg fiber gratings have unique applications both in opticalcommunication and sensor field, such as filters and sensors.This article is mainly about chemical sensing characteristicsof fiber Bragg gratings.We have explained the reason of chemicalsensing characteristic of FBG in the theory, and we have done lotsof experiments to test our theory.At the same time, we haveintroduced some advanced research in the FBG’s chemical sensingcharacteristic in the world, and brought forward the realisticvalue of our research.Firstly, We deduced waveguide modes of single and multimodefibers by use of Maxwell equation.We deduced briefly fielddistribution of fiber gratings using couple mode theory.We strictlydeduced couple mode theory of FBGs using weak waveguideapproximation, and the relation of wavelength and grating periodwas obtained, which is the useful tool for analyzing optical spectraof FBGs.Secondly, based on all the theories described above, we designand fabricate some FBG with different period.Through a series ofexperimental fabrications, we summarized factors of affectingspectra of FBGs including the length of FBGs, grating period, orderof couple modes, refractive-index changes of fiber and the quittingof Hydrogen.FBG cannot be directly used as gas or liquids sensors, becauseit is not sensitive to external refractive index. By a wet chemicaletch-erosion procedure, the cladding layer of FBG can be reducedto several micrometers. The radiation field can reach the externalmedium. When the external refractive index changes, the effectiverefractive index of fiber changes and the center wavelength of theetch-eroded FBG shifts accordingly. Thus,the fiber Bragg gratingcan be used as the chemical sensor to measure solution concentrationor index.Then we focused on the experiments of chemical sensingcharacteristic of fiber Bragg gratings.According to the experimentresults, we drew pictures of wavelength and index.At the same timewe put the same fiber Bragg grating in different solution, andobserved the shift of resonance peaks. In the experiment ,the NaClsolution with different concent ration is used to change theexternal refractive index of FBG. The center wavelength ofetch-eroded FBG shifts when the concent ration of NaCl solutionchanges. The relationship between the off set of wavelength and theconcent ration of NaCl solution is approximately linear. Inaddition , the relationship between the transmit ting power and theconcent ration of NaCl solution is al so approximately linear.In industry, sometimes people need measure concentration ofsome dangerous solution.Fiber Bragg gratings sensor are verysuitable to this measurement.Along with development of study offiber gratings, the application field of fiber Bragg gratings willbe broader. The properties of fiber Bragg gratings will be usedbetter.
Study on Relative Fitness and Resistant Inheritance Mode for R-fenpropathrin and R-spirodiclofen Populations of Tetranychus Urticae Koch
This article through indoor resistant selection for Tetranychus urticae to fenpropathrin and spirodiclofen, studying on biological characteristics,and resistant of resistant populations under different temperature provided the reliable theory basis for pesticides scientificly and reasonably used and the comprehensive governance of the and got the following main research results:1.Study on the biological characteristics of - fenpropathrin (R-fen) and -spirodiclofen (R-spi) populations under different temperature The state developmental time,female sex ratio,female life and fecundity of R-fen、R-spi and sensitive population (S) of T.urticae were studied on the effect of the temperature in conditions with17℃,20℃,25℃,28℃,32℃,36℃six temperature gradients, illumination of 14h, relative humidity(70±5)%. The results indicated that each T.urticae population’s state developmental time, whole generation time and female life were shorten with the temperature risen;And the female sex ratio with temperature changed but not present regularity, and had nothing to do with resistance; There was a relationship rose at first and then decreased between each population of fecundity and temperature, and in 28℃reached the maximum value when a fecundity: S﹥R-spi﹥R-fen.2.Study on the of R-fen and R-spi populations under different temperatureConstructing resistance and sensitive experimental population life tables under different temperature analysed the temperature on the effects of experimental population parameters. The results showed that the relations were a second-degree parabola for the net reproductive rate (R0), the intrinsic growth rate (rm), the finite increase rate (λ) with the temperature, respectively,and population double time (t) and temperature were tending to pour parabola relation, while the mean generation time (T) and temperature in a linear relationship.T.urticae population growth exsisted a low and high temperature inhibition phenomenon. With the net reproductive rate (R0) to determine the relative fitness of two resistant populations (R-fen and R-spi),the results indicated that the relative fitness of resistant populations were less than 1 under different temperature, and existed different degree of biological fitness defects.Among them in low temperature (17℃) or high temperature (36℃), the relative fitness of two resistant populations were closed to 1, namely the adaptation of low and high temperature was consistent between T.urticae resistant and sensitive populations.3.Study on the resistant of R-fen and R-spi populations Under 28℃the cross breeding and back cross to T.urticae resistant population with sensitive population of parental and filial generations concluded that the resistant inheritance mode of T.urticae to fenpropathrin was monogentic and non-complete dominant in autosomal,and its cross F1 hybrids dominant degrees D were 0.4325 and 0.4379,respectively;While the resistant inheritance mode of T.urticae to spirodiclofen was polygentic and non-complete dominant in autosomal, and its cross F1 hybrids dominant degrees D were 0.3515 and 0.3401,respectively.