电磁场与微波课程“TAKES”教学方法的研究

电磁场与微波是通信工程、电子信息和电气等专业学生的必修课。该课程具有抽象程度高、不易理解和公式复杂等特点。为此提出了一种“TAKES”教学方法,从技术(T)、应用(A)等引入相关知识点(K),进行课程实验(E)与仿真(S),巩固知识点(K);引导学生进行电磁场方面的应用(A)与技术(T)的研究。通过这样的循环,激发学生的学习兴趣,拓展课程知识,对学生科研能力和创新能力的培养具有重要意义。

Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and water, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research were simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in water resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

The Influence of Climate Change and Variability on Aircraft Take-off and Landing Performance;a Case Study of the Abeid Amani Karume International Airport-Zanzibar

Climate change (CC) and variability have been world widely reported to pose number of risks in aviation industry including accidents, astray, and other operational difficulties. The impact of weather on landing and take-off performances has been several times experienced at Abeid Amani Karume International Airport (AAKIA);however, the influence of climate change and variability to the aircraft performance needs to be assessed. Thus, this study investigated the influence of climate change and variability on aircrafts take-off and landing performances. Specifically, the study investigated;i) the influence of climate change on Take-off Distance Required (TODR) and Maximum Take-off Mass (MTOM) for different types of aircraft;ii) the influence of climate variability to the aircraft landing performance on light, medium and heavy aircraft and lastly, iii) the study investigated the seasonal and annual variability on aircraft landing performance due to climate variability. The datasets used in this study include the eight years (2014-2021), aircraft operational records (diversion and missed approach events) and Aviation Routine Weather Reports (METAR) records which were utilized as the indicators for landing performance, the long-term (1990-2020) annual maximum temperatures (Tmax) which was used to determine the TODR and MTOM. Statistical tools including mean, percentage changes, correlations, regression, and the chi-square test were used for analysis and hypotheses testing. The results revealed that light and medium aircraft categories were significantly most affected on diversion events as compared to the heavy categories;however, for the missed approach events the impact was vice versa. Moreover, the seasonal and annual variability on diversion and missed approach events were significantly different (at p ≤ 0.001). As for the take-off performance, results show that the TODR and MTOM were significantly increasing and decreasing (at p ≤ 0.001), based on increasing air temperatures. Therefore, the study concludes that the changing climate has significantly affected aircraft by increasing the TODR and decreasing the MTOM, while the climate variability has significantly affected landing performance by influencing the diversion and missed approach events. Thus, the study recommends (i) further research works including the feasibility study on runway extension for the safety of future aircraft operations at the AAKIA and (ii) proper maintenance and improvement of the Instrumental Landing Systems (ILS) as an adaptation measures to the landing aircraft during bad weather events.

一种高性能CMOS电流模Winner-take-all电路

提出了一种新颖的CMOS电流模Winner-take-all(WTA)电路.该电路利用可再生比较器提高了电路的解析度和速度,没有使用电流镜,而是利用整流电路输出电流,从而改善了电路的精确度,不同于传统的树型WTA电路.还提出了一种新的并行N输入WTA结构.在TSMC 0.18μm CMOS工艺下设计了一个8输入WTA电路,并与已有的WTA电路进行了比较.仿真结果表明,该电路可以达到1nA的解析度和99.99%的精确度,同时面积小,功耗低,非常适合于各种嵌入式智能应用.

Influence of Interrupted Childhood Biographies on Health Development: Evaluation of the Scientific Literature on the Example of Being Taken into Care*

Background: An interrupted family history, as is the case after taking someone into care, can complicate collecting family anamnesis data. In addition, the interrupted family history itself could be considered part of a person’s risk profile. Aim and methods: Literature analysis was conducted to examine whether there are scientific studies on health development after placement in out-of-home-care in order to recognise any existing medical characteristics that may be relevant for internal medical care. Results: There are few scientific publications on the health development of people after being placed in out-of-home-care. Direct reactions to the stress of being taken into custody include nausea and fever. However, effects that go beyond the acute situation and last into adulthood have also been described, such as AD(H)D, asthma, diabetes, cancer, hypertension and cardiovascular diseases (myocardial infarction, stroke), epilepsy and increased overall mortality in adulthood. Studies show that not only previous experience but also the stress of being taken into care is triggers for this. Conclusion: Information about a previous institutionalisation can hence be important for internal medical practice. The available scientific literature shows heterogeneous study methodology and no group of people with experience of out-of-home-placement has yet been scientifically accompanied for a long time period. Further studies on this could help to better weigh up the consequences of omitting and conducting an intervention for child/youth protection as well as to improve the medical care for this group of people.

“have a V-inf”及“take a V-inf”结构的句法与语义分析

在英语语言中 ,人们可以说 :“Letmehaveatry !” ,却不可以说 :“Letmetakeatry !” ;可以说 :“Hetookalookatherphoto.”却不可以说 :“Hetookalistentotheradio.”有的语言学家认为这类结构是英语语言中的奇特现象 ;而另有一些学者又将其归属于习惯用法。然而 ,经对大量的英语语言事实进行观察和研究后 ,文章认为这类结构是有规律可循的 ,并从句法和语义的角度分析了这类结构的内部机制 ,深入浅出地阐述了这类结构的有关特性。

基于语料库的动词搭配习得研究——以动词‘Take’的惯用搭配为例

相关研究表明中国英语学习者英语习得的较大缺陷在于程式化语言的严重缺乏,从而大大影响了语言习得的效率。通过大型书面语料或是语料群之间的比较,发现母语使用者和中国英语学习者在动词惯用搭配使用上存在差别,从中国英语课堂教学和使用的教材上可以探讨存在差异的可能原因。语料比较发现:中国高级英语学习者在动词惯用搭配使用上与母语使用者没有显著差别,但课堂教学和教材在动词惯用搭配的出现频次上却存在严重不足。这一结果支持了深层次的词汇知识学习可能依靠通过大量阅读的附带习得,而不是完全依赖于有意识指导。

Analysis of the Heroine's Mental Growth in I'll Take You There

This thesis makes an analysis of the heroine's mental growth from the initial phase of the heroine's mental trauma to the struggling phase and to the mature phase. It analyzes the reasons and manifestations for her mental solitariness,expounds her confusion and struggling during her growth from the perspective of psychoanalysis and reveals her mental maturity in the end after a series of setbacks and conflicts during pursuit of affection,friendship and kinship. In some senses,the heroine's mental growth displayed in this thesis is the psychological portrayal of some contemporary college students,which has certain educational significance to the student readers especially those who possess the similar life experience and accesses them to have an incisive understanding of real life.

隐喻映射与情感意义——以英语动词TAKE为例的个案研究

概念性隐喻中的词义发展辐射状延伸是词义范畴延伸的主要手段,其中的情感因素是映射中的加工对象。笔者认为,跟语言相关的情感意义与概念/经验意义并不是同一语言现象:它们具有本质的不同。本文通过分析英语动词TAKE的词义延伸特征,尝试建立一种情感意义模型。研究发现:(1)概念特征与情感特征在隐喻映射中并行发展,后者附着于前者之上,两者共同形成词项意义的辐射模型;(2)积极-消极与褒扬-贬抑属于两个不同情感特征维度,二者虽存在交叉关系,但并不一一对应;(3)这些情感语义特征具有强度上的差别。这一个案研究有待走向深入与系统,从而为语言教学、语文辞书修订以及翻译提供深度支持。

Modeling of Carrier-based Aircraft Ski Jump Take-off Based on Tensor

A general mathematical model of carrier-based aircraft ski jump take-off is derived based on tensor. The carrier, the aircraft body and the movable parts of the landing gears are treated as independent entities. These entities are assembled into a multi-rigid-body system with flexible links. Dynamical equations of each entity are derived on the basis of the Newton law and the Euler transformation. Using the invariance property of the tensor, the dynamical and kinematical equations are converted to tensor forms which are invariant under time-dependent coordinate transformations. Then the tensor-formed equations are expressed by the matrix operation. Differential equation group of the matrix form is formulated for the programming. The closure of the model is discussed, and the simulation results are given.

Design of A Hydraulic Power Take-off System for the Wave Energy Device with An Inverse Pendulum

This paper describes a dual-stroke acting hydraulic power take-off （PTO） system employed in the wave energy converter （WEC） with an inverse pendulum. The hydraulic PTO converts slow irregular reciprocating wave motions to relatively smooth, fast rotation of an electrical generator. The design of the hydraulic PTO system and its control are critical to maximize the generated power. A time domain simulation study and the laboratory experiment of the full-scale beach test are presented. The results of the simulation and laboratory experiments including their comparison at full-scale are also presented, which have validated the rationality of the design and the reliability of some key components of the prototype of the WEC with an inverse pendulum with the dual-stroke acting hydraulic PTO system.

Biomechanical and dynamic mechanism of locust take-off

The biomimetic locust robot hopping vehicle has promising applications in planet exploration and reconnaissance. This paper explores the bionic dynamics model of locust jumping by using high-speed video and force analysis. This paper applies hybrid rigid-flexible mechanisms to bionic locust hopping and studies its dynamics with emphasis laid on the relationship between force and jumping performance. The hybrid rigid-flexible model is introduced in the analysis of locust mechanism to address the principles of dynamics that govern locust joints and mechanisms during energy storage and take-off. The dynamic response of the biomimetic mechanism is studied by considering the flexi- bility according to the locust jumping dynamics mechanism. A multi-rigid-body dynamics model of locust jumping is established and analyzed based on Lagrange method; elastic knee and tarsus mechanisms that were proposed in previous works are analyzed alongside the original bionic joint configurations and their machinery principles. This work offers primary theories for take-off dynamics and establishes a theoretical basis for future studies and engineering applications.

An Oscillating Wave Energy Converter with Nonlinear Snap-Through Power-Take-Off Systems in Regular Waves

Floating oscillating bodies constitute a large class of wave energy converters, especially for offshore deployment. Usually the Power-Take-Off（PTO） system is a directly linear electric generator or a hydraulic motor that drives an electric generator. The PTO system is simplified as a linear spring and a linear damper. However the conversion is less powerful with wave periods off resonance. Thus, a nonlinear snap-through mechanism with two symmetrically oblique springs and a linear damper is applied in the PTO system. The nonlinear snap-through mechanism is characteristics of negative stiffness and double-well potential. An important nonlinear parameter γ is defined as the ratio of half of the horizontal distance between the two springs to the original length of both springs. Time domain method is applied to the dynamics of wave energy converter in regular waves. And the state space model is used to replace the convolution terms in the time domain equation. The results show that the energy harvested by the nonlinear PTO system is larger than that by linear system for low frequency input. While the power captured by nonlinear converters is slightly smaller than that by linear converters for high frequency input. The wave amplitude, damping coefficient of PTO systems and the nonlinear parameter γ affect power capture performance of nonlinear converters. The oscillation of nonlinear wave energy converters may be local or periodically inter well for certain values of the incident wave frequency and the nonlinear parameter γ, which is different from linear converters characteristics of sinusoidal response in regular waves.

结合Winner-Take-All的足球机器人控制策略研究

在足球机器人运动过程中,足球机器人处于一个实时对抗的复杂环境中,这就需要机器人有较高的实时运动过程应对能力。需要对每个关键时刻,例如:多机器人抢球过程、单机器人控球过程等,做出合理的应对措施。许多策略的研究都只注重单机器人控球过程的路径规划,没有考虑到多机器人竞争的过程,导致足球机器人整个运动过程中的一些关键步骤的缺失,丧失了完整性,忽略了实时的对抗性。拟采用新的策略解决上述问题:第一步是将采用WTA(Winner Take All)竞争模型去有效的解决多机器人竞争问题;第二步将采用一种改进的APF(Artificial Potential Field)路径规划法来进行避障。解决了传统APF算法的弊端,提高了效率。通过仿真实验,验证了理论的正确性,也验证了所提理论的科学性和实用性,为以后在其他科学领域的实践奠定了基础。

Capture Performance of A Multi-Freedom Wave Energy Converter with Different Power Take-off Systems

Among the wave energy converters (WECs), oscillating buoy is a promising type for wave energy development in offshore area. Conventional single-freedom oscillating buoy WECs with linear power take-off (PTO) system are less efficient under off-resonance conditions and have a narrow power capture bandwidth. Thus, a multi-freedom WEC with a nonlinear PTO system is proposed. This study examines a multi-freedom WEC with 3 degrees of freedom: surge, heave and pitch. Three different PTO systems (velocity-square, snap through, and constant PTO systems) and a traditional linear PTO system are applied to the WEC. A time-domain model is established using linear potential theory and Cummins equation. The kinematic equation is numerically calculated with the fourth-order Runge–Kutta method. The optimal average output power of the PTO systems in all degrees of freedom are obtained and compared. Other parameters of snap through PTO are also discussed in detail. Results show that according to the power capture performance, the order of the PTO systems from the best to worst is snap through PTO, constant PTO, linear PTO and velocity-square PTO. The resonant frequency of the WEC can be adjusted to the incident wave frequency by choosing specific parameters of the snap through PTO. Adding more DOFs can make the WEC get a better power performance in more wave frequencies. Both the above two methods can raise the WEC’s power capture performance significantly.

Cure Behaviors and Water Up-take Evaluation of a New Waterborne Epoxy Resin

Cure behaviors and water up-take evaluation of a low cost, ecofriendly and water soluble epoxy resin prepared by reaction between epichlorohydrin and PEG400, PEG600 and PEG1000, respectively, were investigated using non-isothermal differential scanning calorimetry （DSC） and gravimetrical method, respectively. Factors affecting the cure behaviors as well as water up-take of waterborne epoxy resins, such as amount of triethylenetetramine （TETA） and triethylene diamine （TEDA）, PEG molecular weight, curing temperature, were systematically investigated. The prepared water soluble epoxy resins can be cured under room temperature with the shape of the curing curves similar to that expected for an autocatalytic reaction.

A Synchronous Electronic Let-off and Take-up Device

A synchronous electronic let-off and take-up device isdesigned.The device is controlled by a single-chipcomputer and driven by two step motors.It has somefunctions such as keeping the warp tension constant dur-ing the weaving instant,releasing the warp tension whenloom is stopping and straining warp when loom is start-ing.By means of these functions,the stop mark of thewoven fabrics is eliminated.In addition,this device canapply to weaving variant-pick-density fabrics.

Problems and Barriers Impeding the Implementation of MagLev Assisted Aircraft Take-Off and Landing Concept

Nowadays, the success of the new technology development and deployment process depends not only on technical, technological solutions, but also on solving the non-technological problems and crossing the societal and psychological barriers. A large international European projects, GABRIEL1 had developed a maglev assisted aircraft take-off and landing, that was applied to conceptual design of aircraft and required on-board and ground systems, had analysed all impacts (effects of concept deployment on effectiveness, safety, security, noise, emissions) and had demonstrated the safe applicability by concept validation. The applied methodology, used methods and the results of the Gabriel projects had been described and discussed by 55 project deliverables. This paper has a special goal: investigating the problems and barriers of possible implementing of the radically new technology, aircraft MagLev assisted take-off and landing. The study was started by identification and classification of the problems and barriers. After it, the problems were systematically analysed by use of special methodology containing the understanding (description) of the problems, investigation of the possible solutions and discussing their applicability (mainly by use of the Gabriel project results). The paper has three major sections: 1) description of the Gabriel concept and project results, 2) introducing some related thoughts on general aspects of new technology developments, and 3) discussion on the problems and their solutions. The major classes of the problems are the 1) technical, technological problems as developing a radically new solution, landing the undercarriage-less aircraft on the magnetic tracks, 2) stakeholders’ problems as decision makers kicking against supporting the developments of so radically new technologies and 3) society barriers like society worrying on and fear of future passengers on flying by aircraft have not conventional undercarriage systems. The paper will show that these problems have safe and cost-effective solutions.

一种改进的winner-take-all模型及在图像中的应用

作为一种广泛存在于各个领域的竞争现象,关于赢者通吃(winner-take-all)的大部分研究太复杂以至于难以很好地理解该现象。为了用简单的方式解释winner-take-all现象,提出了一个改进的winner-take-all模型,由离散时间差分方程表示,该模型的状态空间是一个矩阵并且模型具有多范数可选性,对应的初始输入矩阵中具有最大输入值的元素最终获胜。对提出模型的收敛性和稳定性进行了严格的理论分析,并将该赢者通吃模型应用于图像处理的实验中,分别比较了单层和多层赢家通吃模型的效率。实验正确地生成了winner-take-all现象,表现了多层winner-take-all图像处理的高性能,理论和实验都验证了所提出模型的正确性和有效性。

英语动词take与名词的搭配

take是个非常活跃的动词,它与各类名词连用构成意义各异的短语、成语、俗语或俚语。本文对take与名词的搭配能力、构成形式和表达语义等方面进行探讨。