查询词典 thesis

To solve the exsisting problems in the realization of the LFM/CW radar, the thesis presents a technique for dynamically measuring the LFM/CW signals, which can accomplish the dynamic measurements of FM linearity, FM bandwidth and FM slop of the transmitted signals of LFM/CW radars. This technique creates an effective and accurate means of judging the performance of LFMCW radars. The linearity-correction techniques presented in the thesis successfully make the linearity of the transmitted signals of an actual LFM/CW radar reduce from approximately 25% to 0. 1%(or r. m. s linearity of 0.04%), better than the best results (0.22%) obtained by foreign researchers with complex linearization closed-loop in the same kind of LFM/CW radars, according to the published literatures during the last decade. In order to improve the capability of the real-time processing and range-cells management of LFM/CW radars, the principle of equivalent mixing by lacking-sampling process of band-pass real signals is proposed based on the well-proved improvedversion of sampling theorem of band-pass real signals. This principle is used to configure the range-segments processing of the beat signals of an actual LFM/CW radar. The techniques of system-background interference suppression and the beat signal's dynamic range suppression are proposed, and are realized in an actual LFM/CW radar to demonstrate their effectiveness.

针对线性调频连续波雷达实现中急待解决的技术问题，文中提出并验证了线性调频连续波信号的综合动态测试技术，可以完成对线性调频连续波雷达发射信号的扫频线性度、扫频带宽和扫频斜率的综合动态测试，为衡量实际线性调频连续波雷达的系统性能创立了精确有效的测试手段；文中建立的非实时闭环动态校正技术使一部实际的线性调频连续波雷达的发射信号（时带积3×10〓）的扫频线性度从25%改善为0.1%（方均根线性度0.04%），优于国外已公布的80年代同类雷达中采用复杂的实时闭环动态校正环路所获得的实际结果（0.22%）；为了改善线性调频连续波雷达的实时性和分辨单元数处理能力，文中发展完善了实带通信号的采样定理并给予了严格证明，并在此基础上提出了欠采样等效混频原理，将其应用于实际线性调频连续波雷达的距离分段处理中；针对线性调频连续波雷达中系统背景干扰和回波动态范围问题，创立了系统背景综合抑制技术和频域动态范围压缩技术，并将它应用于实孔线性调频连续波雷达系统中，显示出它们的有效性。

The thesis consists of five chapters: chapter one discusses the correlative theory of Logistics, then dissertates the condition and current of modern Logistics and the problems of Chinese Logistics. Chapter two introduces and analyzes the develop actuality of Chinese railway freight forward enterprises. Chapter three discusses the primary theory of Third Party Logistics. On this basic, it analyzes the actuality of Chinese railway Third Party Logistics, and finds the leading factors that influence the development of Third Party Logistics enterprises. Chapter four offers the concept of modern Logistics reengineer, and then analyzes it with SWOT. On this basic, the thesis brings forward that the way which Chinese railway freight forward enterprises become modern Logistics enterprises. At last, it prospects the future of railway freight forward enterprises developing modern Logistics, including the current of global Logistics and Internet. Chapter five enumerates two representative and successful cases from domestic and overseas of railway Third Party Logistics enterprises.

本文共分五章，第一章从物流的相关理论出发，论述了现代物流的现状和发展趋势以及我国物流发展历史回顾及存在的问题；第二章介绍并分析了中国铁路货运代理企业的发展现状；第三章介绍了第三方物流的基本理论、国内外第三方物流发展现状以及第三方物流市场供需状况，并在此基础上对我国铁路发展第三方物流的现状进行分析，找出了影响第三方物流企业发展的主要因素；第四章给出了现代物流再造的概念界定，然后对其进行了SWOT分析，并在此基础上提出了中国铁路货运代理企业向现代物流转型的对策，最后对铁路货运代理企业发展现代物流进行了展望，主要包括全球物流发展趋势和互联网发展趋势；第五章列举了中外两个比较典型的铁路发展第三方物流的成功的案例，分别是法国铁路公司的公铁联运和汽车物流和中铁联合物流有限责任公司。

In this thesis this author mainly studies the theory and methods of ship wave-making resistance. Detailed analyses of New Slender-Ship Theory are made and corresponding calculation methods are presented . This thesis aims at finding an algorithm of wave-making resistance calculation suitable for various kinds of ships.

论文工作是研究船舶兴波阻力理论与方法，对新细长船理论进行了较详细的分析，对其具体的计算方法做了深入的研究，目的是探讨可适用于多种船型的有效的兴波阻力算法。

This thesis presents the studies of U-shape gantry structure of container gantry crane, and dynamic simulation and fatigue life estimation of its rigid anti-sway. The main contends are as follows: Supposed that trolley frame is composed of spring structure, due to larger trolley gauge of U-shape gantry structure. For the gantry crane, a series spring dynamic vibrating model with three masses, three freedoms of degrees is built in this thesis and vibrating calculus equations are precisely resolved by mode analyses rule.

本文研究集装箱门式起重机U型门架结构及其刚性减摇系统的动态仿真和疲劳寿命估算，主要内容如下：由于U型门架结构小车轨距较大，本文建立了考虑小车架为弹性结构时门式起重机的三质量三自由度串联弹性动力学振动模型，用模态分析法求解振动系统微分方程组的数值精确解。

In the last new years , as the demands of wireless communication system grows rapidly , the bands of microwave frequency had been saturated with various communication applications . To achieve wider spectrum for high-speed and high-capacity transmission , bands of millimeter-wave frequency are the solution of this problem . The advantage of MMW wireless communication systems is wider bandwidth comparing with microwave communication systems . To utilize the spectrum efficiently , many methods of complexly digital modulation is proposed . The more complex modulation , the higher linearity is required , and more various phase of signals are required to accomplish process of modulation . Therefore high-linearity and quadrature-phase modulator and demodulator are the emphasis of this thesis . For high level of integration , high performance and low cost , this chip is fabricated by the complementary oxide semi-conductor 0.13um process . A compact size of direct down-conversion and direct up conversion circuits will be presented in this thesis .

近年来随著无线通讯产业的蓬勃发展，微波频带已经趋近於饱和，为了追求更宽的频谱来达到更快传输速率及高资料容量的传输，宽频的毫米波频段提供了解决此问题的途径，毫米波无线通讯系统提供了相对於微波通讯系统宽频的优点，且为了更有效的使用频谱，各种不同且复杂的数位调变方式及方法被发表出来，越复杂的调变方式其所需的线性度越高，且需要更多不同的相位讯号来完成调变的过程，因此高线性度及四相位的调变及解调器将是此篇论文的研究重点，为了达到高整合性，高效能，及低成本的电路设计，我门利用互补式金氧半导体制程来完成此电路设计，因此一小面积的直接降频(Direct down-conversion)及直接升频(direct up-conversion)电路将在文中介绍。

The research subject in this thesis is the part of the research project in advance of National Defence of the Tenth Five-year Plan.The primary coverage of this thesis includes nuclear power equipment steam turbine and condenser system.

本研究是十五国防预研项目核动力装置动态仿真中的子课题，其主要内容是围绕着核动力装置汽轮机和冷凝器系统来展开的。

In China, there is no research in the field previously. This thesis supported by the Ministry Advanced Research Foundation of China, make a basic study of the instrument. Its achievements read as follows:(1) A new analytic method based on the concept of an equivalent volume force presented in this thesis, which solve the problem of piezoelectric beam, is simple, clear and reliable. By means of it, the design parameters for QRS have been calculated and analyzed serially, i. e., optimum electrode configurations are chosen, the side ratio of beam is determined, and the formula of electrode location efficiency is derived.

在我国这方面的研究尚属空白，本文在兵器部预研基金项目的支持下，对这种器件进行了基础性研究，从而填补了国内空白，具体包括如下内容：(1)提出了等效体力概念，以此为基础建立了一种分析压电振梁问题的新方法——等效体力分析法，该方法物理图象清晰、计算简明、结果可靠，它可以对QRS的设计参数进行系统的理论分析。

Main points of the thesis are as follows:(1) The main function models and information relations between these models in the CAPP system in the integrated CAD/CAM project are explained, a new process plan design method is mentioned based on analyses of process plan design. This method is based on the process plan prototype, and develops the prototype little by little until the perfect process plan is completed, the prospect of this method is discussed;(2) The feature abstracting rules and methods are studied, a feature coding system is developed based on GT, all the defined feature models are described by the mathematical methods;(3) The integrated method of CAD/CAPP based on features is mentioned, this method defines a feature exchanging model, and develops an interface software to exchange design data into technology data base, this technology data base includes the design and technology information of the parts;(4) The process plan reasoning method based on features is created, this method uses Mycin algorithm to solve the reasoning of the feature process plan. A process plan making system is developed. In this system part process plan is made by the semi-intelligent method, this method uses the feature reasoning, feature process chain searching and man-computer talking together;(5) The main structure of the HOPE system is introduced, a shaft drawing and its process plan made by this system are shown, the data process problem in process drawing making is also discussed;(6) A new method of describing process rule is introduced, this method uses IfThen rules and neural nets weight values together to describe process rules, the BP algorithm is adopted in this method;(7) The optimal machining sequence problem of the process steps on the same fixturing is discussed, optimal algorithms SA is applied to solve this problem, the result shows that this method is more efficient than the traditional method;(8) All jobs in the thesis are summarized. In order to carry out the research in the future, some rational proposals are given.

全文论述的内容主要有下列几个方面：(1)较为系统地阐述了CAD／CAM一体化工程项目中CAPP系统的主要功能模块及其信息流程，在分析工艺设计过程的基础上，提出了基于特征原型的渐进式工艺设计方法，并探讨了该方法的应用前景；(2)研究了零件特征提取的原则和方法，在成组技术的基础上，开发了一套基于特征的分类编码系统，并在提取零件特征的基础上，定义了零件特征的数据模型，开发了基于轴类零件特征的参数化设计系统；(3)研究了基于特征的CAD／CAPP集成的方法，通过定义零件特征数据模型的存储结构，开发了将设计数据转换到工艺数据库中的接口程序，为后续的CAPP系统提供必要的零件形状和工艺信息；(4)研究了基于特征的工艺推理方法，将Mycin算法应用到工艺决策中，开发了基于特征的工艺推理及工艺方案生成系统，在系统中综合运用特征推理、特征加工工艺链查询及人机对话相结合的半智能化方法确定零件加工工艺；(5)介绍了整个HOPE系统的总体结构，通过运行HOPE系统绘出了一轴类零件的零件图，并生成了该零件的加工工艺方案，初步探讨了基于特征的工序图生成技术中数据处理问题；(6)研究了工艺设计过程中知识如何有效表示的问题，提出了将显式的IF-THEN规则表示与隐式神经网络权值表示相结合的工艺知识表示方法，并利用BP算法进行了工艺知识表示的初步研究；(7)研究了工艺设计过程中同一安装下工步优化排序问题，利用神经网络中基于模拟退火的理论来解决该工步优化排序问题，实践证明该方法较传统的算法具有更高的效率；(8)总结了本文所进行的研究工作，为今后进一步开展工作提出了较为合理的建议。

Depending on the history of Zhuang , my thesis attempts to investigate the ethnic memory of Zhuang in an all-round way. The memory is very useful, because they contribute to forming the self-representation of the ethnicity. Have investigated the transmittance process in Zhuang society of ethnic memory in my thesis, which have offered comparatively rational exposition for history of Zhuang and current situation .

论文试图通过对壮族族群现存的为族群或族群中的大多数所共享的记忆形态的历史性考察，以壮族族群的起源、发展、形成与延续为背景，探讨在几千年的历史时空变幻中，壮族族群的集体记忆经历了怎样的传递过程，以及这一过程对族群的自我表象施加了怎样的影响，从而为壮族族群自我认同的历史现状提供较为合理的解释。

And Cohen's criticism of the principle of self-ownership is refutation of the thesis of self-ownership because the principle of self-ownership is supported by the thesis of self-ownership.

柯亨注意到，从直觉出发，这一命题似乎具有不可抗拒的道德吸引力。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。